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Sample records for suez au rapport

  1. Gulf of Suez, Egypt

    SciTech Connect

    Schuetz, K.I. )

    1988-08-01

    The Gulf of Suez is an intracratonic rift basin which originated in the early Miocene on the once-continuous Arabo-African plate. The Precambrian crystalline basement is overlain by a platform cover of Early Cambrian to Eocene age. There is no evidence of tectonic precursors to the Miocene breakup. Marine transgressions, for example during the Carboniferous and Cretaceous, followed wide embayments caused by long-wavelength oscillations trending northwest-southeast on the North African craton. This article discusses the geologic history of the Gulf.

  2. ASTER Suez Canal

    NASA Technical Reports Server (NTRS)

    2000-01-01

    One of the most important waterways in the world, the Suez Canal runs north to south across the Isthmus of Suez in northeastern Egypt. This image of the canal covers an area 36 kilometers (22 miles) wide and 60 kilometers (47 miles) long in three bands of the reflected visible and infrared wavelength region. It shows the northern part of the canal, with the Mediterranean Sea just visible in the upper right corner. The Suez Canal connects the Mediterranean Sea with the Gulf of Suez, an arm of the Red Sea. The artificial canal provides an important shortcut for ships operating between both European and American ports and ports located in southern Asia, eastern Africa, and Oceania. With a length of about 195 kilometers (121 miles) and a minimum channel width of 60 meters (197 feet), the Suez Canal is able to accommodate ships as large as 150,000 tons fully loaded. Because no locks interrupt traffic on this sea level waterway, the transit time only averages about 15 hours. ASTER acquired this scene on May 19, 2000.

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five

  3. Suez Canal, Gulf of Suez, Sinai Peninsula, Egypt, as seen from the Apollo 7

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Suez Canal, Gulf of Suez, Sinai Peninsula, United Arab Republic (Egypt), Mediterranean Sea, as seen from the Apollo 7 spacecraft during its 13th revolution of the earth. Photographed from an altitude of 126 nautical miles, at ground elapsed time of 19 hours and 42 minutes.

  4. Rapport in Distance Education

    ERIC Educational Resources Information Center

    Murphy, Elizabeth; Rodriguez-Manzanares, Maria A.

    2012-01-01

    Rapport has been recognized as important in learning in general but little is known about its importance in distance education (DE). The study we report on in this paper provides insights into the importance of rapport in DE as well as challenges to and indicators of rapport-building in DE. The study relied on interviews with 42 Canadian…

  5. Oil potential of western Gulf of Suez

    SciTech Connect

    Hargras, M.; Hunter, G.; Nairn, A.E.M.

    1983-03-01

    Since 1886, Egyptian and foreign companies have explored the Gulf of Suez by classical mapping and geophysical techniques. During that time 13 oil and as fields have been discovered. Average daily production currently is of the order of 50,000 BOPD. Structurally, the western Gulf of Suez is divided into two major provinces: West Bakr and West Zeit. Within each province, fields are located over structural traps. As a result of drilling it is apparent that the structures resulted from major movement during the early Miocene. A major unconformity occurs at the top of the lower Miocene Nukhul Formation; and the beds of the overlying middle Miocene Belayim Formation transgress on to rocks as old as Precambrian. The Nubia Sandstone, one of the best reservoirs, is a blanket deposit over the whole gulf ranging in thickness from 130 m (425 ft) to in excess of 660 m (2150 ft). The Miocene sands are more sporadic in their distribution and thickness. Three depocenters are known in West Bakr, Shukheir, and Wacdi Dib areas. Further reservoirs of lesser importance are Cretaceous sands, 6.5 m (21 ft) to 32 m (105 ft) thick throughout the area, Eocene carbonates, and Miocene reefs. Production up to the present has been from structural traps; future expansion of production will depend upon our ability to locate stratigraphic traps. Sands sourced by the shales have seldom given high yields. The hope is that through the generation of depositional environment models it will be possible to define prospects where the optimum sand/shale ratio of 1/4 to 1/6 can be found.

  6. Games of Rapport.

    ERIC Educational Resources Information Center

    Corbin, Sandra J.

    1980-01-01

    Board games called Games of Rapport are being developed at the University of Alberta. The first, "Angels and Devils," is designed for play by nursing home residents. Results of a study involving "Angels and Devils" show that board games are useful in communicating rehabilitative objectives and sources of conflict. (Author/BEF)

  7. Geology of the Warda discovery, Gulf of Suez, Egypt

    SciTech Connect

    Vargo, J.N.; Greet, M.J.; Collings, B.P.; Davis, C.B.; Miller, M.H. )

    1991-08-01

    British Gas, as operator for its partners, Yukong Ltd., and Union Pacific Petroleum Suez Ltd., recently discovered the Warda field in the Gulf of Suez in November 1990. Discovery well Hb78-2, located 4 km off the mouth of the Wadi Araba on the west side of the north-central Gulf of Suez, reached a total depth of 8,400 ft in Nubia clastics. Oil was tested in the Hb78-2 from five separate clastic intervals at a cumulative flow rate of approximately 7,000 BOPD of 20-24{degree} API with no water. Currently, an appraisal well program is underway to extend the limits of the field. This significant new-field discovery is located in a part of the Suez basin that previously considered to have limited oil potential. Geophysical assessment of the structure used exploration 3-D seismic coverage and concurrently acquired potential-fields datasets. The Warda structure at Kareen-Rudeis levels is a broad four-way closure, trending northwest-southeast, which drapes over older pre-Miocene tilted fault blocks. The Warda structure lies downthrown to a major Clysmic shoulder fault and is bounded on the northeast by another Clysmic down-to-the-basin normal fault. Cross faulting is noted at the deeper levels, and particularly influences the rift boundary faults. According to burial-history modeling, oil generation occurred within 4-5 million years after the Eocene-Senonian carbonate source rocks achieved onset of oil generation at a birthline of 10,000-11,000 ft subsea. The Cretaceous-Carboniferous Nubia sandstones apparently have acted as a conduit for oil migration from the adjacent Lagia hydrocarbon kitchen a few kilometers to the northeast.

  8. 46 CFR 69.7 - Vessels transiting the Panama and Suez Canals.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) All vessels intending to transit the Panama Canal, other than vessels of war, must be measured and certificated under the system prescribed in 35 CFR part 135. (b) All vessels intending to transit the Suez... Navigation, part IV. (c) Panama Canal and Suez Canal tonnage certificates are in addition to...

  9. 46 CFR 69.7 - Vessels transiting the Panama and Suez Canals.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) All vessels intending to transit the Panama Canal, other than vessels of war, must be measured and certificated under the system prescribed in 35 CFR part 135. (b) All vessels intending to transit the Suez... Navigation, part IV. (c) Panama Canal and Suez Canal tonnage certificates are in addition to...

  10. 46 CFR 69.7 - Vessels transiting the Panama and Suez Canals.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) All vessels intending to transit the Panama Canal, other than vessels of war, must be measured and certificated under the system prescribed in 35 CFR part 135. (b) All vessels intending to transit the Suez... Navigation, part IV. (c) Panama Canal and Suez Canal tonnage certificates are in addition to...

  11. 46 CFR 69.7 - Vessels transiting the Panama and Suez Canals.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) All vessels intending to transit the Panama Canal, other than vessels of war, must be measured and certificated under the system prescribed in 35 CFR part 135. (b) All vessels intending to transit the Suez... Navigation, part IV. (c) Panama Canal and Suez Canal tonnage certificates are in addition to...

  12. 46 CFR 69.7 - Vessels transiting the Panama and Suez Canals.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) All vessels intending to transit the Panama Canal, other than vessels of war, must be measured and certificated under the system prescribed in 35 CFR part 135. (b) All vessels intending to transit the Suez... Navigation, part IV. (c) Panama Canal and Suez Canal tonnage certificates are in addition to...

  13. 75 FR 57911 - Application To Export Electric Energy; GDF SUEZ Energy Marketing NA, Inc.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-23

    ... Application To Export Electric Energy; GDF SUEZ Energy Marketing NA, Inc. AGENCY: Office of Electricity Delivery and Energy Reliability, DOE. ACTION: Notice of application. SUMMARY: GDF SUEZ Energy Marketing NA... utilities, Federal power marketing agencies and other entities within the United States. The...

  14. Intentionally Building Rapport with Students

    ERIC Educational Resources Information Center

    Starcher, Keith

    2011-01-01

    Developing rapport with students is important. Carson (1996) found that when alumni reflected on professors they had encountered 30 years ago, the quality most frequently associated with effective teachers was this: their attitude toward and relationship with students. In this article, the author shares the positive consequences of intentionally…

  15. Extensional hard linkages, eastern Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    McClay, Ken; Khalil, Samir

    1998-06-01

    The Araba Abu Durba area on the eastern margin of the Gulf of Suez exhibits two superb outcrop examples of extensional hard linkages in a rift basin. Here, three large, domino-style, basement-cored, northeast-dipping fault blocks are formed by a series of major northwest-trending normal faults. These are offset by two north-northeast trending sinistral oblique-slip transfer faults that terminate in horsetail normal fault splays. The transfer faults do not extend across the entire rift basin. Detailed mapping and structural analysis show that they developed by breakage of initial low-strain relay ramps along reactivated north-northeast trending basement fabrics between overlapping northwest-trending normal fault segments. Paleostrain analysis of fault-slip indicators shows that both the normal and the sinistral oblique-slip transfer faults were formed synchronously in response to northeast-southwest extension, perpendicular to the main northwest rift trend.

  16. Miocene platform-margin reefs, Gulf of Suez, Egypt

    SciTech Connect

    James, N.P.; Rosen, B.; Coniglio, M.

    1988-02-01

    Jebel Abu Shaar is a completely dolomitized carbonate platform atop a crystalline basement horst on the western side of the Gulf of Suez. Margins of the platform, where not removed by synsedimentary faulting, are formed by well-developed coral reefs. The massive reef carbonates consistently illustrate two stages of growth: a basal paucispecific unit of branching coral bafflestone, mostly Stylophora and a thicker upper unit of diverse coral framestone, dominated by faviids. A deep-water, slope-parallel biostrome of ahermatypic corals, dominated by Dendrophyllia and containing numerous Balanophyllia and Madracis, is present 10 km north of Abu Shaar. Corals are well cemented by numerous rinds of marine cement which is overlain by geopetal internal sediment containing planktonic foraminifers and pteropods.

  17. Extensional tectonics and collapse structures in the Suez Rift (Egypt)

    NASA Technical Reports Server (NTRS)

    Chenet, P. Y.; Colletta, B.; Desforges, G.; Ousset, E.; Zaghloul, E. A.

    1985-01-01

    The Suez Rift is a 300 km long and 50 to 80 km wide basin which cuts a granitic and metamorphic shield of Precambrian age, covered by sediments of Paleozoic to Paleogene age. The rift structure is dominated by tilted blocks bounded by NW-SE normal faults. The reconstruction of the paleostresses indicates a N 050 extension during the whole stage of rifting. Rifting began 24 My ago with dikes intrusions; main faulting and subsidence occurred during Early Miocene producing a 80 km wide basin (Clysmic Gulf). During Pliocene and Quaternary times, faulting is still active but subsidence is restricted to a narrower area (Present Gulf). On the Eastern margin of the gulf, two sets of fault trends are predominant: (1) N 140 to 150 E faults parallel to the gulf trend with pure dip-slip displacement; and (2) cross faults, oriented NOO to N 30 E that have a strike-slip component consistent with the N 050 E distensive stress regime. The mean dip cross fault is steeper (70 to 80 deg) than the dip of the faults parallel to the Gulf (30 to 70 deg). These two sets of fault define diamond shaped tilted block. The difference of mechanical behavior between the basement rocks and the overlying sedimentary cover caused structural disharmony and distinct fault geometries.

  18. Cost estimate for a proposed GDF Suez LNG testing program

    SciTech Connect

    Blanchat, Thomas K.; Brady, Patrick Dennis; Jernigan, Dann A.; Luketa, Anay Josephine; Nissen, Mark R.; Lopez, Carlos; Vermillion, Nancy; Hightower, Marion Michael

    2014-02-01

    At the request of GDF Suez, a Rough Order of Magnitude (ROM) cost estimate was prepared for the design, construction, testing, and data analysis for an experimental series of large-scale (Liquefied Natural Gas) LNG spills on land and water that would result in the largest pool fires and vapor dispersion events ever conducted. Due to the expected cost of this large, multi-year program, the authors utilized Sandia's structured cost estimating methodology. This methodology insures that the efforts identified can be performed for the cost proposed at a plus or minus 30 percent confidence. The scale of the LNG spill, fire, and vapor dispersion tests proposed by GDF could produce hazard distances and testing safety issues that need to be fully explored. Based on our evaluations, Sandia can utilize much of our existing fire testing infrastructure for the large fire tests and some small dispersion tests (with some modifications) in Albuquerque, but we propose to develop a new dispersion testing site at our remote test area in Nevada because of the large hazard distances. While this might impact some testing logistics, the safety aspects warrant this approach. In addition, we have included a proposal to study cryogenic liquid spills on water and subsequent vaporization in the presence of waves. Sandia is working with DOE on applications that provide infrastructure pertinent to wave production. We present an approach to conduct repeatable wave/spill interaction testing that could utilize such infrastructure.

  19. Miocene platform-margin reefs, Gulf of Suez, Egypt

    SciTech Connect

    Noel, J.P.; Rosen, B.; Coniglio, M.

    1988-01-01

    Jebel Abu Shaar is a completely dolomitized carbonate platform atop a crystalline basement horst on the western side of the Gulf of Suez. Margins of the platform, where not removed by synsedimentary faulting, are formed by well-developed coral reefs. The massive reef carbonates consistently illustrate two stages of growth: a basal paucispecific unit of branching coral bafflestone, mostly Stylophora and a thicker upper unit of diverse coral framestone, dominated by faviids. In the upper unit, the reef crest is massive columnar Porites and less common Caulastrea framestone. The back-reef is a framestone of diverse faviids, mainly Montastrea Favites, and Tarbellastrea, and interbedded reef-flat rhodolite rudstones. The back-reef and reef-flat facies grade onshelf into Stylophora bafflestone biostromers and faviid bioherms. The reef front is a shallow to intermediate depth zone of numerous and diverse faviids, dominated by Montastrea and Acanthastrea framestones, bioclastic sands, and hardgrounds. Deeper zones are mostly small Acanthastrea mounds or rhodolite/bivalve rudstones with scattered faviids and Acanthastrea. Synsedimentary lithification, internal sedimentationm, and bioerosion prevail throughout. A deep-water, slope-parallel biostrome of ahermatypic corals, dominated by Dendrophyllia and containing numerous Balanophyllia and Madracis, is present 10 km north of Abu Shaar. Corals are well cemented by numerous rinds of marine cement which is overlain by geopetal internal sediment containing planktonic foraminifers and pteropods.

  20. Carbonate diagenesis and rifting in the Gulf of Suez

    SciTech Connect

    Purser, B.H.; Orszag-Sperber, F.; Aissaoui, D.M. )

    1988-08-01

    Lower Miocene carbonates of the northwest Red Sea and Gulf of Suez have been deposited on a series of structural blocks where bathymetric relief, created by early rift tectonics, has strongly influenced both sedimentation and early diagenesis. Initial submarine cementation by fibrous calcite and aragonite strongly affects slope deposits, destroying most primary porosity. It was followed by several phases of regional dolomitization whose isotopic signatures suggest nonmarine influence. Undolomitized sediments are the exception. An intense dissolution is the principal agent determining petrophysical qualities of the series. Nonmarine sparitic cements are not important, indicating the dissolved carbonate has been flushed out of the system. Finally, large-scale sulfate replacement affects dolomites adjacent to the middle Miocene primary evaporites. These secondary sulfates are associated with a zone of calcitized dolomite (dedolomite). This diagenetic activity obviously reflects repeated changes in the composition of interstitial waters. Its exceptional intensity is explained by the contemporaneous basin relief; the presence of numerous subparallel blocks has resulted in the development of separate bodies of water relating to both meteoric influx and evaporation. Together with normal marine waters, these fluids of variable density have penetrated the intervening sedimentary platforms via the numerous slopes. It is clear that multiphased carbonate diagenesis is one of the many expressions of early rifting.

  1. Oil window in the Gulf of Suez basin, Egypt

    SciTech Connect

    Shahin, A.N. )

    1988-08-01

    Petroleum in the Gulf of Suez is multisourced mainly by restricted marine Cretaceous to Eocene beds. The Campanian carbonates of the Sudr Formation and the Turonian shales of the Abu Qada Formation are high-quality sources. Other proven sources are carbonate and shale intervals within other sub-Miocene formations. Geothermal modeling calibrated by maturation measurements suggests that the organic-rich lower Miocene marls may not be mature enough to expel hydrocarbons north of the Morgan-Amal fields area but are mature to the south. This could be related mainly to a gradual increase in thermal gradient from north to south (20-55{degree}C/km). A few anomalies do exist, however. Thermal gradients are generally higher in areas where oil accumulated. The depth of peak generation ranges between 5,200 m to the north and 3,300 m to the south. The geographic variations in heat flow, maturation depths, and age of source rocks are not reflected in the timing of hydrocarbon migration. During the middle Miocene, a short-lived salinity crisis resulted in the deposition of massive thick evaporites that form the ultimate seal in the Gulf. The accompanying rapid burial of the underlying sub-Miocene potential source intervals caused them all to sequentially enter the oil window, within a very short time, soon after the evaporites accumulated. This timing was perfect for hydrocarbon preservation: after seal deposition and major disturbing regional tectonic events. The almost simultaneous migration from all the source beds resulted in mixed multisourced hydrocarbon accumulations.

  2. Interpretation of multispectral and infrared thermal surveys of the Suez Canal Zone, Egypt

    NASA Technical Reports Server (NTRS)

    Elshazly, E. M.; Hady, M. A. A. H.; Hafez, M. A. A.; Salman, A. B.; Morsy, M. A.; Elrakaiby, M. M.; Alaassy, I. E. E.; Kamel, A. F.

    1977-01-01

    Remote sensing airborne surveys were conducted, as part of the plan of rehabilitation, of the Suez Canal Zone using I2S multispectral camera and Bendix LN-3 infrared passive scanner. The multispectral camera gives four separate photographs for the same scene in the blue, green, red, and near infrared bands. The scanner was operated in the microwave bands of 8 to 14 microns and the thermal surveying was carried out both at night and in the day time. The surveys, coupled with intensive ground investigations, were utilized in the construction of new geological, structural lineation and drainage maps for the Suez Canal Zone on a scale of approximately 1:20,000, which are superior to the maps made by normal aerial photography. A considerable number of anomalies belonging to various types were revealed through the interpretation of the executed multispectral and infrared thermal surveys.

  3. Evaluation of poly-aromatic hydrocarbons (PAHs) in the aquatic species of Suez Gulf water along El-Sokhna area to the Suez refineries.

    PubMed

    Ali, Nabila A; Ahmed, Omayma E; Doheim, Mamdouh M

    2014-02-01

    The Egyptian Red Sea environment especially along El-Sokhna area to the Suez refineries (Suez) is severely contaminated with organic compounds, as well as overfishing. This may be well contributory to recent serious declines in fish stocks. Fish embryos are also particularly vulnerable to oil exposure, even at extremely low concentrations of less than one part per billion. Consequently, even traces of oil pollution at levels often considered safe for wildlife can cause severe damage to fish. Sixteen polycyclic aromatic hydrocarbons (PAHs) were investigated in ten fish species of aquatic species by high performance liquid chromatography (HPLC). The compositions of PAHs determined in all samples were measured in order to use them as chemical markers for identifying different sources of PAH pollutants in the studied region. The total content of these16 PAHs ranged from 399.616 up to 67,631.779 ng/g wet weight. The data show that these values are considered to be alarmingly high enough to cause lethal toxicity effect by accumulation. All studied aquatic species samples are characterized by relatively high concentrations of the six-membered ring PAHs. The origin of PAHs in the collected samples is either petrogenic, biogenic, or mixed petrogenic and biogenic. PMID:24092254

  4. Now It's Personal: Antecedents and Outcomes of Rapport between Business Faculty and Their Students

    ERIC Educational Resources Information Center

    Granitz, Neil A.; Koernig, Stephen K.; Harich, Katrin R.

    2009-01-01

    "Rapport" refers to when two people "click." Although business education researchers have begun to study rapport, past research has principally focused on students' perceptions of rapport, whereas faculty's perceptions of rapport have never been studied or contrasted with those of students. Understanding this is critical as rapport between faculty…

  5. Examining the positive effects of rapport building: when and why does rapport building benefit adult eyewitness memory?

    PubMed

    Kieckhaefer, Jenna Mitchell; Vallano, Jonathan Patrick; Schreiber Compo, Nadja

    2014-01-01

    Most investigative interviewing protocols recommend building rapport with cooperative adult witnesses to increase the accuracy of their reports. Although a few recent studies support the benefits of rapport building on adult witness recall, no study has examined whether the timing of rapport in relation to post-event misinformation affects recall accuracy, and whether these effects are related to witness anxiety levels throughout the interview. The present study provided two hundred and thirty-three undergraduates with a videotaped mock crime followed by building high or low rapport either before or after they received post-event misinformation. All witnesses were then interviewed about the mock crime. Results indicated that high rapport before misinformation increased the amount of accurate information reported in a subsequent witness interview compared to low rapport. However, these recall benefits were not due to a reduction in anxiety. Theoretical implications and practical recommendations for police interviewing practices are discussed. PMID:24304449

  6. October field: The latest giant under development in Egypt's Gulf of Suez

    SciTech Connect

    Lelek, J.J.; Abdine, A.S. )

    1990-09-01

    October field, the third largest oil field in Egypt, produced 378 MMBO from its discovery in 1977 until January 1990. It is the northernmost giant oil field in the Gulf of Suez Rift basin. Twenty wells from five platforms in approximately 190 ft (58 m) of water currently drain over 3,238 ha. Recent successful field extensions demonstrate the viability of continuing exploration in this oil-rich area. This structurally trapped field is a complex of rotated fault blocks typical of rift basins worldwide. A northwest-trending normal fault with an approximate throw of 1,220 m has trapped an 335-m oil column on the upthrown eastern side. On the upthrown side, the Carboniferous through Oligocene prerift section dips gently to the northeast and is unconformably overlain by generally flat Miocene to Holocene clastics, carbonates, and evaporites. Severe multiple problems result from thick Miocene evaporites hampering seismic definition of the highly productive prerift section. These same evaporites serve as the ultimate seal in October field and throughout the Gulf of Suez. Although four layers are productive, approximately 95% of field reserves are within Carboniferous to Lower Cretaceous massive Nubia Sandstones. The remaining reserves are in more stratified Upper Cretaceous sandstones, basal Miocene rift-fill Nukhul Formation clastics, and a Lower Miocene clastic in the upper Rudeis Formation. Several distinct reservoir accumulations exist, with the deepest and most significant original oil-water contact at {minus}10,670 ft subsea. October field oil gravities range from 14 to 34{degree} API, with an initial solution GOR of 134 to 474 SCF/STB. The hydrocarbon source for all October field oil as well as most Gulf of Suez oil is believed to be the Campanian Brown Limestone Member of the Sudr Formation. Average reservoir parameters for the Nubia Formation are 16% porosity, 236 md permeability, 137 m net pay thickness, and 5,506 psi original reservoir pressure.

  7. Pattern of Blood Stream Infections within Neonatal Intensive Care Unit, Suez Canal University Hospital, Ismailia, Egypt

    PubMed Central

    Kishk, Rania Mohammed; Mandour, Mohamed Fouad; Farghaly, Rasha Mohamed; Ibrahim, Ahmed; Nemr, Nader Attia

    2014-01-01

    Introduction. Blood stream infection (BSI) is a common problem of newborn in neonatal intensive care units (NICUs). Monitoring neonatal infections is increasingly regarded as an important contributor to safe and high-quality healthcare. It results in high mortality rate and serious complications. So, our aim was to determine the incidence and the pattern of BSIs in the NICU of Suez Canal University Hospital, Egypt, and to determine its impact on hospitalization, mortality, and morbidity. Methods. This study was a prospective one in which all neonates admitted to the NICUs in Suez Canal University hospital between January, 2013 and June 2013 were enrolled. Blood stream infections were monitored prospectively. The health care associated infection rate, mortality rate, causative organism, and risk factors were studied. Results. A total of 317 neonates were admitted to the NICU with a mortality rate of 36.0%. During this study period, 115/317 (36.3%) developed clinical signs of sepsis and were confirmed as BSIs by blood culture in only 90 neonates with 97 isolates. The total mean length of stay was significantly longer among infected than noninfected neonates (34.5 ± 18.3 and 10.8 ± 9.9 days, resp., P value < 0.001). The overall mortality rates among infected and noninfected neonates were 38.9% and 34.8%, respectively, with a significant difference. Klebsiella spp. were the most common pathogen (27.8%) followed by Pseudomonas (21.6%) and Staphylococcus aureus (15.4%). Conclusion. The rate of BSIs in NICU at Suez Canal University Hospital was relatively high with high mortality rate (36.0%). PMID:25389439

  8. Pattern of Blood Stream Infections within Neonatal Intensive Care Unit, Suez Canal University Hospital, Ismailia, Egypt.

    PubMed

    Kishk, Rania Mohammed; Mandour, Mohamed Fouad; Farghaly, Rasha Mohamed; Ibrahim, Ahmed; Nemr, Nader Attia

    2014-01-01

    Introduction. Blood stream infection (BSI) is a common problem of newborn in neonatal intensive care units (NICUs). Monitoring neonatal infections is increasingly regarded as an important contributor to safe and high-quality healthcare. It results in high mortality rate and serious complications. So, our aim was to determine the incidence and the pattern of BSIs in the NICU of Suez Canal University Hospital, Egypt, and to determine its impact on hospitalization, mortality, and morbidity. Methods. This study was a prospective one in which all neonates admitted to the NICUs in Suez Canal University hospital between January, 2013 and June 2013 were enrolled. Blood stream infections were monitored prospectively. The health care associated infection rate, mortality rate, causative organism, and risk factors were studied. Results. A total of 317 neonates were admitted to the NICU with a mortality rate of 36.0%. During this study period, 115/317 (36.3%) developed clinical signs of sepsis and were confirmed as BSIs by blood culture in only 90 neonates with 97 isolates. The total mean length of stay was significantly longer among infected than noninfected neonates (34.5 ± 18.3 and 10.8 ± 9.9 days, resp., P value < 0.001). The overall mortality rates among infected and noninfected neonates were 38.9% and 34.8%, respectively, with a significant difference. Klebsiella spp. were the most common pathogen (27.8%) followed by Pseudomonas (21.6%) and Staphylococcus aureus (15.4%). Conclusion. The rate of BSIs in NICU at Suez Canal University Hospital was relatively high with high mortality rate (36.0%). PMID:25389439

  9. Neogene tectono-stratigraphic events in Gulf of Suez rift area, Egypt

    SciTech Connect

    Evans, A.L.

    1987-05-01

    Micropaleontologic and sedimentologic studies of Miocene outcrop and borehole sections from the flanks and axial trough of the Suez rift have documented five major tectono-stratigraphic events, or hiatuses, during the Neogene. The first Neogene hiatus spans the late(.) Oligocene to earliest Miocene and separates Miocene from pre-Miocene strata throughout the Gulf of Suez. This erosional event resulted from both low global sea levels in the Oligocene and the initiation of Suez rifting. A second hiatus, from 21 to 19(.) Ma, separates the poorly dated shallow marine Nukhul formation from overlying middle Burdigalian and younger (NN3-NN5) upper bathyal shales of the Rudeis Formation. This hiatus resulted from both low early Burdigalian sea levels and increased rift-related tectonism. A third major event occurs within the Rudeis around 16 Ma (N7, NN4). This mid-Clysmic event of Garfunkel and Bartove is characterized by accelerated uplift of the rift margins and subsidence of the axial trough. Local unconformities are seen over paleohighs, while coarse clastics are deposited in more basinal areas in submarine fans and turbidites. A fourth hiatus at 14 to 13 Ma (N10-N11) separates the middle Miocene (N9) Kareem Formation from the overlying Belayim Formation evaporites. This hiatus may correlate with the initiation of rifting along the Dead Sea-Aqaba system. The fifth Neogene event is a tectonic pulse in the early (.) Pliocene that further rotated many tilted fault blocks. This event is roughly synchronous with the initiation of Red Sea sea-floor spreading and accelerated sinistral motion along the Dead Sea transform at approx. 5 Ma.

  10. Phytoplankton variability in relation to some environmental factors in the eastern coast of Suez Gulf, Egypt.

    PubMed

    Nassar, Mohamed Z; El-Din, Nihal G Shams; Gharib, Samiha M

    2015-10-01

    Water samples were seasonally collected from 12 stations of the eastern coast of Suez Gulf during autumn of 2012 and winter, spring, and summer of 2013 in order to investigate phytoplankton community structure in relation to some physicochemical parameters. The study area harbored a diversified phytoplankton community (138 species), belonging to 67 genera. Four algal groups were represented and classified as Bacillariophyceae (90 species), Dinophyceae (28 species), Cyanophyceae (16 species), and Chlorophyceae (4 species). The results indicated a relative high occurrence of some species namely.; Pleurotaenium trabecula of green algae; Chaetoceros lorenzianus, Proboscia alata var. gracillima, Pseudosolenia calcar-avis, and Pseudo-nitzschia pungens of diatoms; Trichodesmium erythraeum and Pseudoanabaena limnetica of cyanophytes. Most of other algal species were fairly distributed at the selected stations of the study area. The total abundance of phytoplankton was relatively low (average of 2989 unit/L) in the eastern coast of Suez Gulf, as compared its western coast and the northern part of the Red Sea. The diversity of phytoplankton species was relatively high (2.35-3.82 nats) with an annual average of 3.22 nats in the present study. The results concluded that most of eastern coast of Suez Gulf is still healthy, relatively unpolluted, and oligotrophic area, which is clearly achieved by the low values of dissolved phosphate (0.025-0.3 μM), nitrate (0.18-1.26 μM), and dissolved ammonium (0.81-5.36 μM). Even if the occurrence of potentially harmful algae species was low, the study area should be monitored continuously. The dissolved oxygen ranged between 1.77 and 8.41 mg/L and pH values between 7.6 and 8.41. The multiple regression analysis showed that the dissolved nitrate and pH values were the most effective factors that controlled the seasonal fluctuations of phytoplankton along the eastern coast of Suez Gulf during 2012-2013. PMID:26407862

  11. Structural evolution of the southern transfer zone of the Gulf of Suez rift, Egypt

    NASA Astrophysics Data System (ADS)

    Abd-Allah, Ali M. A.; Abdel Aal, Mohamed H.; El-Said, Mohamed M.; Abd El-Naby, Ahmed

    2014-08-01

    We present a detailed study about the initiation and reactivations of Zeit-El Tor transfer zone, south Gulf of Suez rift, and its structural setting and tectonic evolution with respect to the Cretaceous-Cenozoic tectonic movements in North Egyptian margin. NE trending zone of opposed-dipping faults (22 km wide) has transferred the NE and SW rotations of the sub-basins in central and south Gulf of Suez rift, respectively. The evolution of this zone started by reactivation of the NE oriented late Neoproterozoic fractures that controlled the occurrence of Dokhan Volcanics in the rift shoulders. Later, the Syrian Arc contraction reactivated these fractures by a sinistral transpression during the Late Cretaceous-Eocene time. N64°E extension of the Oligo-Miocene rift reactivated the NE fractures by a sinistral transtension. During this rifting, the NE trending faults forming the transfer zone were more active than the rift-bounding faults; the Upper Cretaceous reverse faults in the blocks lying between these NE trending faults were rotated; and drape-related reverse faults and the positive flower structures were formed. Tectonic inversion from contraction to extension controlled the distribution and thickness of the Upper Cretaceous-Miocene rocks.

  12. Relationship between sediment morphology and oil pollution along the Suez Canal beaches, Egypt

    SciTech Connect

    Barakat, M.A.K.; Shimy, T.M.; Mostafa, Y.M.

    1996-10-01

    In this study, marine surface sediments are collected from nine locations along the Suez Canal in order to investigate the relationship between the morphology of sands in the studied beaches and pollution by oil. Basically, the studied samples were analyzed by three techniques: grains-size analysis, microscopic examination, and gas chromatographic (GC) analysis. This study concluded that medium sand is the major class represented in the studied marine sediments. Pollution in these sand grains increases in the irregular grains more so than in the more rounded grains. Also, deep surface points, pitting, and fissures are considered to be good sites to precipitate oil contamination. Also, the presence of iron oxides may be taken as evidence for tanker ballast washings. The heavy fraction (zircon) shows more contamination than the light fraction (quartz) in these samples. Finally, GC profiles have shown two types of samples: one typical of weathered or highly weathered crude oil patterns and the other for samples with very highly weathered profiles. The relationship obtained between morphology studies and both oil content and GC chromatogram profiles indicates that all of the studied locations are suffering from pollution of oil that is spilled while shipping petroleum through the Suez Canal.

  13. Structures and sequence stratigraphy of the Miocene successions, southwestern Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    Abd El Naby, Ahmed; Abdel-Rahman, Ahmed; Abd El-Aal, Mohamed; Alhamshry, Asmaa

    2016-05-01

    The subsurface structural evolution, facies changes and sequence stratigraphic interpretations of the Miocene successions of the southwestern part of the Gulf of Suez, Egypt, were studied by seismic reflection data of Twenty seven 3D seismic sections supported by the composite, velocity and vertical seismic profiles (VSP) logs of eight wells. Among them five sections and two geoseismic cross sections were selected to reveal the structural framework and depositional history of the study area. The analysis of depth-structure contour maps revealed that the Miocene strata are dissected by two major faults trends: The NW-SE trending faults (Clysmic trend) and the NE-SW trending cross faults running nearly perpendicular to the Clysmic faults. The facies changes of the syn-depositional Miocene units are controlled by the structural framework of the southern part of the Gulf of Suez being evolving diapiric structure of South Gharib Formation. The Miocene units are subdivided into two major 3rd order depositional sequences: S1 and S2.

  14. [The corvette "Nordstjernen's" voyage to the opening of the Suez Canal--naval medicine in 1869].

    PubMed

    Ongre, Aksel; Pettersen, Jan Sommerfelt; Munch, Johan Storm

    2002-06-30

    When the Norwegian corvette Nordstjernen was in the North Sea bound for Port Said to be present at the opening of the Suez Canal on 17 November 1869, an officer suffered a rupture of m. triceps brachii when he was drawn into the machinery during a storm. He was put ashore in Harwich; four days after the injury he was hospitalized in Colchester. The voyage was eventful in other ways too. Another officer died from typhoid fever in Ismailia. On the Swedish frigate Vanadis, also present at the opening of the Suez Canal, one of the doctors died from lung infection and was buried in Smyrna; a twelve-feet high column of white marble was taken from the ruins of Aesculap's temple and put on his grave. Denmark was represented by the frigate Sjaelland. During a storm in the North Sea, one seaman fell down on the deck from the foresail yard and suffered contusions and a fracture of the left clavicle. These cases illustrate challenges that faced our ancestors. The accident happened when the ship was in the Netherlands sector of the North Sea as we know it today. Today the Coast Guard could have arranged transport by helicopter and hospitalized the patient in about two hours. PMID:12555606

  15. Psychometric Characteristics of the Professor-Student Rapport Scale

    ERIC Educational Resources Information Center

    Ryan, Rebecca G.; Wilson, Janie H.; Pugh, James L.

    2011-01-01

    In this study, the authors assessed the psychometric properties of the Professor-Student Rapport Scale, the first scale to measure professor-student rapport. The scale was found to have adequate test-retest and internal-consistency reliability. In addition to these findings, measures used to determine convergent validity included the Working…

  16. Neuro-Linguistic Programming, Matching Sensory Predicates, and Rapport.

    ERIC Educational Resources Information Center

    Schmedlen, George W.; And Others

    A key task for the therapist in psychotherapy is to build trust and rapport with the client. Neuro-Linguistic Programming (NLP) practitioners believe that matching the sensory modality (representational system) of a client's predicates (verbs, adverbs, and adjectives) improves rapport. In this study, 16 volunteer subjects participated in two…

  17. Professor-Student Rapport Scale: Six Items Predict Student Outcomes

    ERIC Educational Resources Information Center

    Wilson, Janie H.; Ryan, Rebecca G.

    2013-01-01

    Rapport between students and teachers leads to numerous positive student outcomes, including attitudes toward the teacher and course, student motivation, and perceived learning. The recent development of a Professor-Student Rapport scale offers assessment of this construct. However, a Cronbach's [alpha] of 0.96 indicated item redundancy, and the…

  18. Rapport in Negotiation: The Contribution of the Verbal Channel

    ERIC Educational Resources Information Center

    Bronstein, Ilan; Nelson, Noa; Livnat, Zohar; Ben-Ari, Rachel

    2012-01-01

    This study examined the contribution of verbal behavior to the creation of rapport in negotiation, while methodologically addressing the issue of dependence between dyadic measures, which is inherent to the concept of rapport, with the Actor-Partner Interdependence model. The approach adopted is substantially different from that of past research,…

  19. 77 FR 39689 - Application To Export Electric Energy; IPR-GDF SUEZ Energy Marketing North America, Inc.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-05

    ... Application To Export Electric Energy; IPR-GDF SUEZ Energy Marketing North America, Inc. AGENCY: Office of... Marketing North America, Inc. (GSEMNA) has applied for authority to transmit electric energy from the United..., Federal power marketing agencies, and other entities within the United States. The existing...

  20. Crustal and uppermost mantle structure beneath the continental rifting area of the Gulf of Suez from earthquake tomography

    NASA Astrophysics Data System (ADS)

    El Khrepy, Sami; Koulakov, Ivan; Al-Arifi, Nassir

    2016-02-01

    Suez rift is one of the active seismic zones in the northward continuation of the Red Sea, as indicated by recent earthquake records from the Egyptian National Seismological Network (ENSN). We present a new model of P and S wave velocities in the crust and uppermost mantle beneath the Gulf of Suez and surrounding areas, including the northern portion of the Red Sea. Using the records from 94 seismic stations, we analyzed ~ 66,000 P and ~ 17,000 S wave arrival times from 9700 events. The travel time tomography inversion was performed using the iterative LOTOS code. The spatial resolutions of the derived models were assessed using several synthetic tests. The most prominent anomaly is a sharp high-velocity anomaly beneath the Red Sea, which is observed in both the P and S models at all depth intervals. We interpret this anomaly to be oceanic crust that was formed through extension associated with a dispersed system of spreading centers. Beneath the Gulf of Suez, the upper and middle crusts appear to be strongly heterogeneous and are dominated by low-velocity anomalies, indicative of the continental nature of the crusts. In contrast, at a depth of 30 km, we observe a prominent high-velocity anomaly along Gulf of Suez, which is interpreted to be the result of crustal thinning associated with extension between the Sinai block and the African Plate. The thickness of the crust beneath the rift is estimated to be approximately 25 km, whereas that in the surrounding areas appears to be 30-35 km. In the northwestern part of the area, we observe a low-velocity zone in the middle and lower crusts that coincide with intense seismicity and a well-developed system of recent faults on the surface. This region may mark a possible area of northward propagation of the Suez Rift zone.

  1. Oligocene lacustrine tuff facies, Abu Treifeya, Cairo-Suez Road, Egypt

    NASA Astrophysics Data System (ADS)

    Abdel-Motelib, Ali; Kabesh, Mona; El Manawi, Abdel Hamid; Said, Amir

    2015-02-01

    Field investigations in the Abu Treifeya area, Cairo-Suez District, revealed the presence of Oligocene lacustrine volcaniclastic deposits of lacustrine sequences associated with an Oligocene rift regime. The present study represents a new record of lacustrine zeolite deposits associated with saponite clay minerals contained within reworked clastic vitric tuffs. The different lithofacies associations of these clastic sequences are identified and described: volcaniclastic sedimentary facies represent episodic volcaniclastic reworking, redistribution and redeposition in a lacustrine environment and these deposits are subdivided into proximal and medial facies. Zeolite and smectite minerals are mainly found as authigenic crystals formed in vugs or crusts due to the reaction of volcanic glasses with saline-alkaline water or as alteration products of feldspars. The presence of abundant smectite (saponite) may be attributed to a warm climate, with alternating humid and dry conditions characterised by the existence of kaolinite. Reddish iron-rich paleosols record periods of non-deposition intercalated with the volcaniclastic tuff sequence.

  2. Geology and habitat of oil in Ras Budran field, Gulf of Suez, Egypt

    SciTech Connect

    Chowdhary, L.R.; Taha, S.

    1987-10-01

    The Ras Budran structure at the deepest mappable seismic reflector, the top of the Kareem Formation (middle Miocene), is a broad northeast-southwest-trending anticlinal feature with an anomalous strike nearly at right angles to the main Gulf of Suez trend. Oil is produced from three units of Nubian Formation sandstone from a depth of 11,000-12,000 ft (3352-3657 m). The lower unit of Paleozoic age averages 10% porosity and has up to 200 md in-situ permeability. Wells completed in this unit produce up to 2000 BOPD. In contrast, the sands to the upper two units of the Early Cretaceous have 15-20% porosity and up to 700 md permeability. Wells completed in this unit produce 6000-8000 BOPD. The Ras Budran structure was formed primarily during an intra-Rudeis tectonic phase (lower Miocene). Oil migration for accumulation in the structure started in the late Miocene or Pliocene when the Santonian Brown Limestone and the Eocene Thebes Formation, the main source beds in the Gulf of Suez, reached the threshold of oil generation at a burial depth of approximately 10,000 ft (3048 m). At this depth, the organic matter in the source beds had a high transformation ratio (0.10 to 0.15), high yields of C/sub 15+/ soluble organic matter and C/sub 15+/ saturated hydrocarbons, vitrinite reflectance (R/sub 0/) of 0.62%, and a time-temperature index (TTI) value of 15. Oil migration from mature source beds in adjoining lows into low-potential Nubian reservoirs is easily explained by fault planes that acted as conduits for oil migration. 16 figures, 3 tables.

  3. Reproductive biology of the Suez Canal spider crab Schizophrys aspera (H. Milne Edwards, 1834: Crustacea: Brachyura: Majidae).

    PubMed

    El-Serehy, Hamed A; Al-Rasheid, Khaled A; Ibrahim, Nesreen K; Al-Misned, Fahad A

    2015-11-01

    A reproductive biology study of the spider crab Schizophrys aspera (H. Milne Edwards, 1834) was conducted in the Suez Canal from July 2012 to June 2013. The annual sex ratio (Male:Female) of S. aspera was female biased with values of 1:1.25. Out of the four ovarian development stages of this crab, two stages were observed in the Suez Canal throughout the whole year. The ovigerous crab's carapace width varied from 28 to 52 mm. This crab species can spawn during most of the year in the canal water, with a peak during late spring and early winter. The fecundity of ovigerous females ranged between 2349 and 13600 eggs with a mean of 5494 ± 1486 eggs. Female crabs that reached sexual maturity exhibited a minimum carapace width varying between 22 and 46 mm, and fifty percentage of all ovigerous females showed a carapace width of 36 mm. PMID:26587008

  4. Geology and habitat of oil in Ras Budran field, Gulf of Suez, Egypt

    SciTech Connect

    Chowdhary, L.R.; Taha, S.

    1987-05-01

    Deminex discovered the Ras Budran oil field in 1978. Discovery well EE 85-1 was drilled in about 140 ft of water, 4 km off the Sinai coast of the Gulf of Suez. Appraisal drilling (EE 85-2, 3, and 4 wells) confirmed the presence of a major field with an estimated 700 million bbl oil in place. The field, developed from three wellhead platforms, went on production in April 1983. To date, 20 development wells have been drilled. The Ras Budran structure at the deepest mappable seismic reflector, top Kareem (middle Miocene), is a broad northeast-southwest-trending anticlinal feature striking nearly at right angles to the main Gulf of Suez trend. At pre-Miocene producing horizons, the structure is complex and consists of a northeast-dipping flank (14-15) broken into several blocks by faults and limited to the south and west by major bounding faults. Oil is produced from three units of Nubian sandstone at a depth of 11,000 to 12,000 ft. The lower unit of Paleozoic age averages 10% porosity and up to 200 md in -situ permeability. The wells completed in this unit produce up to 2000 BOPD. In contrast, the sands of the upper two units of Lower Cretaceous age have a 15-20% porosity and up to 700 md permeability. The wells completed in these units produce 6000-8000 BOPD. The Ras Budran structure was primarily formed during the intra-Rudeis tectonic phase (lower Miocene). Migration of oil for accumulation in Ras Budran started late in the upper Miocene or Pliocene when the Santonian Brown Limestone and the Eocene Thebes Formation, the main source beds in the Gulf, reached the threshold of oil generation at a burial depth of about 10,000 ft (3000 m). At these depths, the organic matter in the source beds have a transformation ratio (0.10 to 0.15), increased yields of C15 + soluble organic matter and C15 + saturated hydrocarbons, a vitrinite reflectance of 0.62%, and a TTI value of 15.

  5. Tectonic and structural setting of the northeastern central Gulf of Suez area using aeromagnetic data

    NASA Astrophysics Data System (ADS)

    Zahra, Hesham Shaker; Nakhla, Adel Mokhles

    2016-03-01

    Cumulative qualitative and quantitative analysis of the filtered regional and residual magnetic components of the northeastern central area of the Gulf of Suez, as well as images of the second vertical derivatives of the reduced to the northern magnetic pole map of the total magnetic intensity field images, supplemented with the available geologic information, enabled the precise delineation of the detailed structural configuration of the basement complex, which consequently illustrated the structural deformational pattern of the overlying sedimentary succession. The basement tectonic map reflects a series of N-S to NNW-SSE oriented belts of high and low basement structures. These structures are interrupted by a set of NE-SW crossing diagonal faults having varying throws and creating promising blocks for exploration. An often remarkable correlation between the reduced to the magnetic pole map and the basement relief map is noted, in particular the outline of various oil fields. A larger number of the tilted fault blocks and basement culminations have been outlined and numerous interesting exploration prospects are indicated, which appear to warrant further follow up investigation.

  6. Facies and sequence stratigraphy of some Miocene sediments in the Cairo-Suez District, Egypt

    NASA Astrophysics Data System (ADS)

    Tawfik, Mohamed; El-Sorogy, Abdelbaset; Mowafi, Ahmed; Al-Malky, Mazen

    2015-01-01

    The shallow-water siliciclastics and carbonates of the Miocene sediments in the Cairo-Suez District, Egypt represent an epiric ramp. The facies are characterized by stacked high-frequency cycles with restricted ramp to shoal margin sequences. Based on an extensive micro- and biofacies documentation, six lithofacies associations were defined and their respective depositional environments were interpreted. A sequence-stratigraphic analysis was carried out by integrating lithostratigraphic marker beds, facies relationships, stratigraphic cycles, and biostratigraphy. The investigated sections were subdivided into three third-order sequences, named S1, S2 and S3. S1, is interpreted to correspond to the Late Burdigalian stage (18-16.38 My), S2 corresponds to the Late Burdigalian-Early Langhian stage (16.38-14.78 My), and S3 represents the Late Langhain-Early Serravallian stage (14.78-13.66 My). Each of the three sequences was further subdivided into fourth order cycle sets and fifth-order cycles.

  7. Mechanical stratigraphy of sedimentary section - implications for petroleum exploration, Gulf of Suez, Egypt

    SciTech Connect

    Gawarecki, S.L.; Coffield, D.Q.; Schamel, S.

    1987-05-01

    Mechanical response of sedimentary units to extension varies, depending on their rheology. In the Gulf of Suez, knowledge of the mechanical stratigraphy assures better control for seismic interpretation, structural analysis, and delineation of possible hydrocarbon traps. Recent field studies and seismic analysis allow delineation of the structural response of a range of prerift and synrift lithologies. The prerift section is divided into three major mechanical/stratigraphic units: Precambrian basement, Nubian sandstone, and Cenomanian through Eocene shallow marine platform rocks. Single fault planes in the basement are expressed in the overlying Nubian sandstone as closely spaced parallel faults and fractures. In contrast, the inhomogeneous Late Cretaceous-Paleogene section of alternating brittle and ductile beds drapes over the underlying normal faults. The synrift section may comprise three mechanical/stratigraphic units: (1) early Miocene carbonates and clastics; (2) middle-late Miocene evaporites; and (3) Pliocene-Recent clastics. The lower synrift rocks respond to faulting much like the Cenomanian-Eocene units. The evaporite section acts as a major detachment zone, with underlying faults dying out upward. Onshore, faults in the more brittle passive cover rocks sole into the underlying evaporites. Thus, faults at the surface may be entirely decoupled from master faults in the early synrift and prerift strata. Mechanical response in the synrift section is complicated by syntectonic processes such as growth faulting, compaction, and lateral facies changes.

  8. Timing of structural development of oil traps in Gulf of Suez, Egypt

    SciTech Connect

    Chowdhary, L.R.; Shaheen, S.

    1988-01-01

    To date, more than 40 oil fields with an estimated 25billion bbl of oil in place have been discovered in the Gulf of Suez, Egypt. These oil accumulations are present both in the pre-graben and graben-fill cycles which are separated by Oligocene tectonic phase, hitherto considered to be responsible for differentiation and formation of oil traps. In the present study, the structural development of many oil traps is related to intra-Rudeis tectonic phase of late early Miocene age. Presence of an a

  9. Hydrocarbon potential, structural setting and depositional environments of Hammam Faraun Member of the Belayim Formation, Southern Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    Nabawy, Bassem S.; El Sharawy, Mohamed S.

    2015-12-01

    The Middle Miocene Belayim Formation is one of the most prolific formations in the Southern Gulf of Suez. It consists of four members; two members are evaporitic (Baba and Feiran) and the other two members are prospective, mostly clastics (Hammam Faraun and Sidri). The hydrocarbon potential and depositional environment of Hammam Faraun Member, the target of the present study, have been studied in 11 wells distributed in the southern province of the Gulf of Suez. The traditional well log data, as well as the Spectral Gamma-Ray logs 'SGR' and dipmeter data were used to evaluate the petrophysical properties and distribution of the Hammam Faraun Member in the Southern Gulf of Suez. It varies greatly in thickness with the greatest thicknesses in GS 365 (372 ft) and GS 373 (430 ft) fields in the central parts and the thinnest at the basin margins of the studied area at GH376 (65 ft) and Ras El Bahar (67.5 ft) fields. It is composed of clastic rocks, mainly shales and sometimes reef carbonates. The very good petrophysical properties of the studied sequence indicate a good reservoir in some fields with good to very good porosity (13.5 ≤ ∅ ≤ 25.0%). The shale volume of this reservoir sequence is less than 33% and the water saturation is less than 42.3%, while the net-pay thickness is up to 58 ft. The SGR and Pe logs indicate that, the studied rocks were deposited mostly in lagoonal to shallow marine environments, with illite and montmorillonite as dominant clay minerals. The dipmeter data obtained in some wells indicate slightly tilted beds, mostly less than 20° with an overall dip direction towards the SW, which represents the regional dip in the Southern Gulf of Suez. Based on dipmeter data, two major angular unconformities can be detected; one at the top of the sequence, separating it from the overlying South Gharib evaporates, and another one at the base of the sequence, separating it from the underlying Feiran Member.

  10. Master's and doctoral theses in family medicine and their publication output, Suez Canal University, Egypt

    PubMed Central

    Nour-Eldein, Hebatallah; Mansour, Nadia M.; Abdulmajeed, Abdulmajeed A.

    2015-01-01

    Background: The completion of a thesis is a significant requirement for both a Master's and a doctorate degree in general practice/family medicine (GP/FM). A postgraduate thesis is a well-planned, time-intensive activity carried out over several years. The quality of the theses can be judged by the proportion of published papers. Objective: This study aimed to describe Master's and doctoral theses in family medicine and their publications between 1982 and 2014. Materials and Methods: GP/FM degree theses were reviewed at the Faculty of Medicine and central Suez Canal libraries. Several characteristics were extracted from each thesis relating to the main researcher, supervisors, themes, and study methods according to predefined criteria. Publications from the theses were described. Results: Over 33 years, 208 theses were completed by 173 GP/FM researchers. The majority of the theses were for Master's degrees (84.1%). Regarding the study design, most of the degree theses were cross-sectional studies (76.9%). The adult population was targeted in 33.7% of research theses. Nonprobability sampling was used in 51%. Rural communities were the setting of research in 43.8%, and primary health center (PHC)-based studies in 59.1%. The “Patient” category exceeded the other categories (28.4%). Publication from theses started in the second decade of research production. Of the degree theses, 21.6% original articles were published. Only 13.3% of articles from theses were published in PubMed-indexed journals. The researcher was first author in 62.2% of published articles. Conclusion: The production of GP/FM theses and their publications are going to increase. Continuous assessment and planning for GP/FM studies are recommended. PMID:25949959

  11. Marine molluscs as biomonitors for heavy metal levels in the Gulf of Suez, Red Sea

    NASA Astrophysics Data System (ADS)

    Hamed, Mohamed A.; Emara, Ahmed M.

    2006-05-01

    Levels of the heavy metals Copper (Cu), Zinc (Zn), Lead (Pb), Cadmium (Cd), Chromium (Cr), Nickel (Ni), Iron (Fe) and Manganese (Mn) were determined in coastal water, sediments and soft tissues of the gastropod limpet, Patella caerulea, and the bivalve, Barbatus barbatus, from seven different stations in the western coast of the Gulf of Suez. The concentrations of heavy metals in water ranged between 3.37-4.78, 18.83-21.46, 2.75-3.17, 0.22-0.27, 0.99-1.21, 2.69-3.65, 3.75-4.56 μg L - 1 and 23.82-32.78 mg g - 1 for Cu, Zn, Pb, Cd, Cr, Ni, Mn and Fe, respectively. The corresponding concentration values in the sediments were 8.65-12.16, 51.78-58.06, 36.52-42.15, 3.23-3.98, 9.03-12.75, 34.31-49.63, 3.28-4.56 and 64.20-70.22 μg g - 1 for Cu, Zn, Pb, Cd, Cr, Ni, Mn and Fe, respectively. The highest accumulated metals were Fe, Zn and Mn in both P. caerulea and B. barbatus, while the lowest one was Cd. The accumulation of metals was more pronounced in P. caerulea than B. barbatus. The highest concentrations of all metals in water, sediments and mollusca were recorded at Adabiya harbour north of the Gulf, while the lowest concentrations were recorded at Gabal El-Zeit and Hurghada. Land based activities and ships awaiting berth are the main source of metal pollution in the northern part of the Gulf.

  12. The Stitches Stayed: Creating Rapport around Women's Work

    ERIC Educational Resources Information Center

    Wall, Mary Clementine; Stasz, Bird

    2010-01-01

    Establishing rapport between researcher and participants when conducting ethnography is essential to the successful outcome of the research. However, when participants are unwilling to engage, a different approach must be adopted. This article is an examination of the appropriation of a situated learning model during fieldwork with a group of…

  13. Peak Alert Time and Rapport between Residence Hall Roommates.

    ERIC Educational Resources Information Center

    Carey, John C.; And Others

    1988-01-01

    Examined whether peak alert time is related to compatibility for college roommates. Data from 66 male pairs and from 55 female pairs of roommates revealed that pairs who were similar on self-reported peak circadian alertness had higher levels of rapport. (Author/NB)

  14. Using Courthouse Portfolios to Establish Rapport and Motivate College Students

    ERIC Educational Resources Information Center

    Gentry, Ruben

    2013-01-01

    Motivation enhances student learning (Wang, 2012). One means for an instructor to stimulate students and get them actively involved is to establish good rapport with them (Cottringer & Sloan, 2003). For this study, county courthouse portfolios were developed and used to build relationships and motivate college students. The strategy was…

  15. Spatial distribution of radioisotopes in the coast of Suez Gulf, southwestern Sinai and the impact of hot springs.

    PubMed

    Ramadan, Kh A; Seddeek, M K; Elnimr, T; Sharshar, T; Badran, H M

    2011-06-01

    This work describes the concentrations of radioisotopes in soil, sediment, wild plants and groundwater in southwestern Sinai. The study area extends from Suez to Abu Rudies along the eastern part of the Suez Gulf. It included two hot springs: Ayun Musa and Hammam Faraoun. No dependence of ¹³⁷Cs concentrations on any of the measured sand characteristics was found, including calcium carbonate. The enrichment of ²²⁶Ra in Hammam Faraoun hot spring was the most prominent feature. The ²²⁶Ra concentration in hot springs of Ayun Musa and Hammam Faraoun were 68 and 2377 Bq kg⁻¹ for sediments, 3.5 and 54.0 Bq kg⁻¹ for wild plants and 205 and 1945 mBq l⁻¹ for the groundwater, respectively. In addition, ²²⁶Ra activity concentration in local sand in the area of Hammam Faraoun was ∼14 times that of Ayun Musa. On the other hand, the ²³²Th concentrations were comparable in the two hot springs, while ¹³⁷Cs concentrations were relatively higher in Ayun Musa. The characteristics and radioelements studies support possible suggestions that the waters in the two hot springs have different contributions of sea and groundwaters crossing different geological layers where the water-rock interaction takes place. PMID:21148168

  16. Multiphase flowmeter successfully measures three-phase flow at extremely high gas-volume fractions -- Gulf of Suez, Egypt

    SciTech Connect

    Leggett, R.B.; Borling, D.C.; Powers, B.S.; Shehata, K.; Halvorsen, M.

    1998-02-01

    A multiphase flowmeter (MPFM) installed in offshore Egypt has accurately measured three-phase flow in extremely gassy flow conditions. The meter is completely nonintrusive, with no moving parts, requires no flow mixing before measurement, and has no bypass loop to remove gas before multiphase measurement. Flow regimes observed during the field test of this meter ranged from severe slugging to annular flow caused by the dynamics of gas-lift gas in the production stream. Average gas-volume fraction ranged from 93 to 98% during tests conducted on seven wells. The meter was installed in the Gulf of Suez on a well protector platform in the Gulf of Suez Petroleum Co. (Gupco) October field, and was placed in series with a test separator located on a nearby production platform. Wells were individually tested with flow conditions ranging from 1,300 to 4,700 B/D fluid, 2.4 to 3.9 MMscf/D of gas, and water cuts from 1 to 52%. The meter is capable of measuring water cuts up to 100%. Production was routed through both the MPFM and the test separator simultaneously as wells flowed with the assistance of gas-lift gas. The MPFM measured gas and liquid rates to within {+-} 10% of test-separator reference measurement flow rates, and accomplished this at gas-volume fractions from 93 to 96%. At higher gas-volume fractions up to 98%, accuracy deteriorated but the meter continued to provide repeatable results.

  17. Reproductive biology of the Suez Canal spider crab Schizophrys aspera (H. Milne Edwards, 1834: Crustacea: Brachyura: Majidae)

    PubMed Central

    El-Serehy, Hamed A.; Al-Rasheid, Khaled A.; Ibrahim, Nesreen K.; Al-Misned, Fahad A.

    2015-01-01

    A reproductive biology study of the spider crab Schizophrys aspera (H. Milne Edwards, 1834) was conducted in the Suez Canal from July 2012 to June 2013. The annual sex ratio (Male:Female) of S. aspera was female biased with values of 1:1.25. Out of the four ovarian development stages of this crab, two stages were observed in the Suez Canal throughout the whole year. The ovigerous crab’s carapace width varied from 28 to 52 mm. This crab species can spawn during most of the year in the canal water, with a peak during late spring and early winter. The fecundity of ovigerous females ranged between 2349 and 13600 eggs with a mean of 5494 ± 1486 eggs. Female crabs that reached sexual maturity exhibited a minimum carapace width varying between 22 and 46 mm, and fifty percentage of all ovigerous females showed a carapace width of 36 mm. PMID:26587008

  18. Structural evolution and Cenozoic tectonostratigraphy of the Cairo-Suez district, north Eastern Desert of Egypt: Field-structural data from Gebel Qattamiya-Gebel Um Reheiat area

    NASA Astrophysics Data System (ADS)

    Hagag, Wael

    2016-06-01

    Detailed field mapping reveals that continental rifting is strongly deforming the Gebel Qattamiya-Gebel Um Reheiat area and the entire Cairo-Suez district, in north Eastern Desert of Egypt. Rift-related structures are predominantly represented by E to WNW, NNW and NW oriented faults. The E to WNW oriented faults are small and build up the Gebel Qattamiya en echelon fault belt, whereas the faults trending NNW and NW establish a pervasive horst and graben structural style involving some rhomb-shape horsts as Gebel Qattamiya (GQRH), Gebel Um Reheiat (GURRH) and south Gebel Um Reheiat (SGURRH). Rock units of the Eocene succession and Oligocene sediments are well exposed and highly controlled by rift-related structures. Rifting was developed through two rift-phases; initial and major ones. The initial phase (a newly recognized phase in this contribution) has been occurred in Late Eocene (Priabonian), while the main phase was prevailing during Late Oligocene-Early Miocene time and is characterized by hydrothermal veins and basaltic eruptions. Continental transtension in the Cairo-Suez district, including the study area, was probably synchronous with a major tectonic stage (Pyrenean-Atlasic movement) of continental collision between African-Arabian and Eurasian plates in Late Eocene-Oligocene time. Field investigation suggests that the transfer of displacement (slip) from the Gulf of Suez proto-rift into the E-W oriented faults ''relays'' is an important mechanism, which helps to explain the current structural framework and tectonic evolution of the Cairo-Suez district. Reactivation of such faults with right-lateral divergent wrenching with NE-SW oriented extension deformed the Cairo-Suez district with several E-W oriented en echelon fault belts (e.g. Gebel Qattamiya fault belt in the study area). Thus the Cairo-Suez district represents an accommodation or transfer zone in northeastern Egypt, intercepting the ''far-field stresses'' from the Arabian-Nubian Shield, the Red

  19. Low-angle normal faulting and isostatic response in the Gulf of Suez: Evidence from seismic interpretation and geometric reconstruction

    NASA Technical Reports Server (NTRS)

    Perry, S. K.; Schamel, S.

    1985-01-01

    Tectonic extension within continental crust creates a variety of major features best classed as extensional orogens. These features have come under increasing attention in recent years, with the welding of field observation and theoretical concepts. Most recent advances have come from the Basin and Range Province of the southwestern United States and from the North Sea. Application of these geometric and isostatic concepts, in combination with seismic interpretation, to the southern Gulf of Suez, an active extensional orogen, allows generation of detailed structural maps and geometrically balanced sections which suggest a regional structural model. Geometric models which should prove to be a valuable adjunct to numerical and thermal models for the rifting process are discussed.

  20. Carcinome basocellulaire de la face: à propos de quatre cas rapportés à Madagascar

    PubMed Central

    Razafindrakoto, Rex Mario; Razafindranaivo, Mananjara Nandrianina; Schammirah, Mahamad Rojovolaarivony; Randriamboavonjy, Rado

    2015-01-01

    Les carcinomes basocellulaires, fréquemment rencontrés dans la race blanche, sont plus rares chez les sujets de race noire. Les zones exposées de la tête sont des sites préférentiels, et une intense exposition aux rayons solaires ultraviolets a été évoquée dans leur étiopathogénie. Les métastases sont exceptionnelles. Les objectifs ont été de démontrer l'existence de carcinomes basocellulaires à Madagascar et d'en évaluer la prise en charge. Les auteurs ont rapporté quatre cas de carcinomes basocellulaires faciaux vus au service d'Oto-rhino-laryngologie du Centre Hospitalier Universitaire d'Antananarivo, avec deux hommes et deux femmes, âgés entre 46 et 70 ans (âge moyen= 53,5 ans). Une exérèse chirurgicale a été pratiquée chez trois patients tandis qu'un patient albinos a été traité par radiothérapie. L’épidémiologie, l’étiologie, l'anatomie pathologique et le traitement des carcinomes basocellulaires de la face ont été discutées à travers une revue de la littérature. PMID:26848344

  1. Rift-related active fault-system and a direction of maximum horizontal stress in the Cairo-Suez district, northeastern Egypt: A new approach from EMR-Technique and Cerescope data

    NASA Astrophysics Data System (ADS)

    Hagag, Wael; Obermeyer, Hennes

    2016-09-01

    An active fault system has been detected along the Cairo-Suez district in northeastern Egypt, applying the EMR-Technique using Cerescope. The E-W (old Mediterranean) and NW-SE (Red Sea-Gulf of Suez) fault-trends are estimated to have ongoing activity. Horizontal EMR-measurements indicate a NW to NNW orientation as a maximum horizontal stress direction (σ1), whereas an E-W orientation to has a secondary tendency. A simplified stress map for the Cairo-Suez district is constructed from the horizontal stress data measured at about 20 locations within the district. The mapped stresses will contribute to the stress data of the Cairo-Suez region on the world stress map (WSM). The present study results indicate rejuvenation of the inherited Mesozoic E-W oriented and Oligocene-Miocene rift-related NW-SE oriented faults. The transfer of rift-related deformation from Red Sea-Gulf of Suez region, which is currently undergoing an extensional stress regime in NE to NNE direction, would explain a seismotectonic activity of the Cairo-Suez district. These results are consistent with a present day NNW oriented compressional stresses attributed to a convergence between the African and Eurasian plates.

  2. Student Views of Instructor-Student Rapport in the College Classroom

    ERIC Educational Resources Information Center

    Webb, Nathan G.; Barrett, Laura Obrycki

    2014-01-01

    Building upon past research on the positive learning outcomes associated with rapport building in the classroom, this study examines the specific behaviors instructors utilize in college classrooms to build rapport with undergraduate students. Participants (N = 230) answered open-ended survey questions about their instructors'…

  3. Instructor-Student and Student-Student Rapport in the Classroom

    ERIC Educational Resources Information Center

    Frisby, Brandi N.; Martin, Matthew M.

    2010-01-01

    This study examined the relationships between instructors and their students, and between students, to determine their roles in building positive relationships and an overall positive classroom environment. Of particular interest was the examination of instructor rapport with students and rapport between students. Students (N = 232) reported on…

  4. Caprellidae (Crustacea: Peracarida: Amphipoda) from the Red Sea and Suez Canal, with the redescription of Metaprotella africana and Paradeutella multispinosa.

    PubMed

    Zeina, Amr F; Guerra-García, José M

    2016-01-01

    The Caprellidae from the Red Sea are reviewed based on the literature data and new collections from the Hurghada coasts. So far, only six valid species has been reported from the Red Sea and Suez Canal: Caprella equilibra Say, 1818, Hemiaegina minuta Mayer, 1890, Metaprotella africana Mayer, 1903, Paracaprella pusilla Mayer, 1890 and Paradeutella multispinosa Schellenberg, 1928 and Pseudocaprellina pambanensis Sundara Raj, 1927. The type material of M. africana (deposited in the Muséum nacional d'Histoire naturelle, Paris) and Paradeutella multispinosa (deposited in the Museum für Naturkunde, Berlin) are redescribed and illustrated in detail. P. pambanensis and H. minuta were the most abundant species in the collections along the northern coast. Most of the sampling effort has been focused on algae from shallow waters; additional substrates such as sediments, hydroids and coral rubble, especially from areas deeper than 15 meters should be explored. The number of caprellid species in the Red Sea is low compared to adjacent waters, as the Mediterranean Sea. However, further research and more extensive caprellid collections should be conducted along the coasts of Saudi Arabia, Yemen, Sudan and Eritrea, which are still unexplored. PMID:27394584

  5. Trace metals in water, sediments and marine organisms from the northern part of the Gulf of Suez, Red Sea

    NASA Astrophysics Data System (ADS)

    El-Moselhy, Khalid Mohamed; Gabal, Mahmoud Nageib

    2004-05-01

    Concentrations of Cd, Pb, Cu and Zn were determined in water, sediments, gastropod ( Bulla umpulla) and green algae ( Ulva lactuca) collected from five stations in the western side of the northern part of the Gulf of Suez during the period February 1993-January 1994. Sediments recorded the highest concentrations of Cd (2.26-4.40 μg/g) and Pb (13.90-28.34 μg/g), While the highest concentrations of the essential metals Cu and Zn were found in B. umpulla (28.19-72.04 and 60.24-108.74 μg/g, respectively). Water and sediments showed similar spatial distribution patterns for the highest mean values of the different metals. Highest values of the studied metals were found at stations influenced by various pollution sources such as harbours, and sewage and industrial drains. In contrast, the lowest concentrations were observed faraway from any pollution source. Calculations of concentration factors (C.F.) for gastropod and algae showed highest C.F. of Cd (4312.5-8705.9) and Pb (2103.3-8317.9) in algae, and highest C.F. of Cu (5288.9-42376.5) and Zn (3686.7-9631.5) in gastropod.

  6. Organic tracers in sediments from the coastal zone of Ras Abu el-Darag, Gulf of Suez

    NASA Astrophysics Data System (ADS)

    Rushdi, Ahmed I.; Kassim, Tarek A. T. A.; Simoneit, Bernd R. T.

    2009-10-01

    Sediment samples from the coastal zone of the Gulf of Suez contain a variety of organic compounds from anthropogenic and natural sources. A total of 12 surface samples of bottom sediments were collected with an Ekman grab sampler along an off-shore transect south of Ras Abu el-Darag. The samples were extracted with a mixture of dichloromethane and methanol (3:1 v/v) after drying and sieving through 250 μm mesh. The extracts were derivatized and analyzed by gas chromatography-mass spectrometry in order to characterize the chemical composition and sources of the organic components. Marine with minor terrestrial biota were the major natural sources of organic tracers and included n-alkanoic acids, sterols and saccharides (5.7-76.7%). Anthropogenic sources, from petroleum related activities, detergent usage for spill cleaning and littering, are indicated by the presence of n-alkanes with carbon preference index ≤1.0, hopanes, steranes, unresolved complex mixture of branched and cyclic hydrocarbons, alkyl nitriles, alkamides and plasticizers. Their total relative concentrations ranged from 23.3 to 97.3% of the total extracts. Petroleum residues from natural seepage may also be part of these hydrocarbons. The levels of anthropogenic inputs decrease from about 94% in coastal zone sediments to about 20% in sediments from the reef front.

  7. Q-values for P and S waves in Southern Sinai and Southern Gulf of Suez Region, Egypt

    NASA Astrophysics Data System (ADS)

    Mohamed, Gad-Elkareem A.

    2014-05-01

    The quality factor Q has been estimated using spectral amplitudes of P and S waves from earthquakes recorded by the seismic network of the Egyptian National Seismological Network (ENSN) in southern Sinai and southern Gulf of Suez region. The earthquakes recorded at nine stations - DHA, NUB, TR1, TR2, KAT, SH2, GRB, HRG and SFG have been used in this study. The spectral amplitude ratios have been calculated between 2 - 20 Hz and single station spectral ratio method has been applied for this purpose. The results show that the quality factors for both P and S waves (Qp and Qs) increase as a function of frequency according to law the Q = Q0fn. By averaging the estimated Q- Value obtained at all stations we calculated the average attenuation laws: Qp = (13.15± 0.76) f0.95± 0.19 and Qs = (20.05± 0.79) f1.03±0.04 for P and S waves respectively. These relations are useful for the estimation of source parameters of earthquakes and simulation of earthquake strong ground motions. The QS /QP ratio for KAT station is less than 1 at lower frequencies, whereas at HRG and SH2 stations QS /QP ratio is are greater than 1.

  8. Training in Compensatory Strategies Enhances Rapport in Interactions Involving People with Möbius Syndrome.

    PubMed

    Michael, John; Bogart, Kathleen; Tylén, Kristian; Krueger, Joel; Bech, Morten; Østergaard, John Rosendahl; Fusaroli, Riccardo

    2015-01-01

    In the exploratory study reported here, we tested the efficacy of an intervention designed to train teenagers with Möbius syndrome (MS) to increase the use of alternative communication strategies (e.g., gestures) to compensate for their lack of facial expressivity. Specifically, we expected the intervention to increase the level of rapport experienced in social interactions by our participants. In addition, we aimed to identify the mechanisms responsible for any such increase in rapport. In the study, five teenagers with MS interacted with three naïve participants without MS before the intervention, and with three different naïve participants without MS after the intervention. Rapport was assessed by self-report and by behavioral coders who rated videos of the interactions. Individual non-verbal behavior was assessed via behavioral coders, whereas verbal behavior was automatically extracted from the sound files. Alignment was assessed using cross recurrence quantification analysis and mixed-effects models. The results showed that observer-coded rapport was greater after the intervention, whereas self-reported rapport did not change significantly. Observer-coded gesture and expressivity increased in participants with and without MS, whereas overall linguistic alignment decreased. Fidgeting and repetitiveness of verbal behavior also decreased in both groups. In sum, the intervention may impact non-verbal and verbal behavior in participants with and without MS, increasing rapport as well as overall gesturing, while decreasing alignment. PMID:26500605

  9. Training in Compensatory Strategies Enhances Rapport in Interactions Involving People with Möbius Syndrome

    PubMed Central

    Michael, John; Bogart, Kathleen; Tylén, Kristian; Krueger, Joel; Bech, Morten; Østergaard, John Rosendahl; Fusaroli, Riccardo

    2015-01-01

    In the exploratory study reported here, we tested the efficacy of an intervention designed to train teenagers with Möbius syndrome (MS) to increase the use of alternative communication strategies (e.g., gestures) to compensate for their lack of facial expressivity. Specifically, we expected the intervention to increase the level of rapport experienced in social interactions by our participants. In addition, we aimed to identify the mechanisms responsible for any such increase in rapport. In the study, five teenagers with MS interacted with three naïve participants without MS before the intervention, and with three different naïve participants without MS after the intervention. Rapport was assessed by self-report and by behavioral coders who rated videos of the interactions. Individual non-verbal behavior was assessed via behavioral coders, whereas verbal behavior was automatically extracted from the sound files. Alignment was assessed using cross recurrence quantification analysis and mixed-effects models. The results showed that observer-coded rapport was greater after the intervention, whereas self-reported rapport did not change significantly. Observer-coded gesture and expressivity increased in participants with and without MS, whereas overall linguistic alignment decreased. Fidgeting and repetitiveness of verbal behavior also decreased in both groups. In sum, the intervention may impact non-verbal and verbal behavior in participants with and without MS, increasing rapport as well as overall gesturing, while decreasing alignment. PMID:26500605

  10. Analysis of the similar epicenter earthquakes on 22 January 2013 and 01 June 2013, Central Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    Toni, Mostafa; Barth, Andreas; Ali, Sherif M.; Wenzel, Friedemann

    2016-09-01

    On 22 January 2013 an earthquake with local magnitude ML 4.1 occurred in the central part of the Gulf of Suez. Six months later on 1 June 2013 another earthquake with local magnitude ML 5.1 took place at the same epicenter and different depths. These two perceptible events were recorded and localized by the Egyptian National Seismological Network (ENSN) and additional networks in the region. The purpose of this study is to determine focal mechanisms and source parameters of both earthquakes to analyze their tectonic relation. We determine the focal mechanisms by applying moment tensor inversion and first motion analysis of P- and S-waves. Both sources reveal oblique focal mechanisms with normal faulting and strike-slip components on differently oriented faults. The source mechanism of the larger event on 1 June in combination with the location of aftershock sequence indicates a left-lateral slip on N-S striking fault structure in 21 km depth that is in conformity with the NE-SW extensional Shmin (orientation of minimum horizontal compressional stress) and the local fault pattern. On the other hand, the smaller earthquake on 22 January with a shallower hypocenter in 16 km depth seems to have happened on a NE-SW striking fault plane sub-parallel to Shmin. Thus, here an energy release on a transfer fault connecting dominant rift-parallel structures might have resulted in a stress transfer, triggering the later ML 5.1 earthquake. Following Brune's model and using displacement spectra, we calculate the dynamic source parameters for the two events. The estimated source parameters for the 22 January 2013 and 1 June 2013 earthquakes are fault length (470 and 830 m), stress drop (1.40 and 2.13 MPa), and seismic moment (5.47E+21 and 6.30E+22 dyn cm) corresponding to moment magnitudes of MW 3.8 and 4.6, respectively.

  11. Provenance, diagenesis, tectonic setting and geochemistry of Rudies sandstone (Lower Miocene), Warda Field, Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    Zaid, Samir M.

    2012-05-01

    The Lower Miocene Rudies sandstones are important oil reservoirs in the southeastern part, Gulf of Suez basin, Egypt. However, their provenance and diagenesis and their impact in reservoir quality, are virtually unknown. Samples from the Warda field, representing the Lower and Middle Rudies, were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower Rudies sandstones have an average framework composition of Q85F7.2R7.8, and 83% of the quartz grains are monocrystalline. By contrast, the Middle Rudies sandstones are only slightly more quartzose with an average framework composition of Q90F7R3 and 86% of the quartz grains are monocrystalline. Rudies sandstones are mostly quartz arenite with subordinate subarkose and sublithic arenites and their bulk-rock geochemistry support the petrographic results. The modal analysis data of studied samples suggest influence of granitic and metamorphic terrains as the main source rock with a subordinate quartzose recycled sedimentary rocks. The geochemical data interpretation on the basis of discriminate function diagrams reveal the source material was deposited on a passive margin. Textural attributes possibly suggest long-distance transport of grains from the source region and indicates a cratonic or a recycled source. Tectonic setting of Rudies Formation reveals that the lower Rudies sandstones are typically rift sandstone and their deposition constrained the beginning of the faulting, while the middle Rudies sandstones were transported from the far along the rift. Diagenetic features include compaction; dolomite, silica and anhydrite cementation with minor iron-oxide, illite, kaolinite and pyrite cements; dissolution of feldspars, rock fragments. Silica dissolution, grain replacement and carbonate dissolution greatly enhance the petrophysical properties of many sandstone samples.

  12. Provenance, diagenesis, tectonic setting and reservoir quality of the sandstones of the Kareem Formation, Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    Zaid, Samir M.

    2013-09-01

    The Middle Miocene Kareem sandstones are important oil reservoirs in the southwestern part of the Gulf of Suez basin, Egypt. However, their diagenesis and provenance and their impact on reservoir quality, are virtually unknown. Samples from the Zeit Bay Oil Field, and the East Zeit Oil Field represent the Lower Kareem (Rahmi Member) and the Upper Kareem (Shagar Member), were studied using a combination of petrographic, mineralogical and geochemical techniques. The Lower Rahmi sandstones have an average framework composition of Q95F3.4R1.6, and 90% of the quartz grains are monocrystalline. By contrast, the Upper Shagar sandstones are only slightly less quartzose with an average framework composition of Q76F21R3 and 82% of the quartz grains are monocrystalline. The Kareem sandstones are mostly quartzarenite with subordinate subarkose and arkose. Petrographical and geochemical data of sandstones indicate that they were derived from granitic and metamorphic terrains as the main source rock with a subordinate quartzose recycled sedimentary rocks and deposited in a passive continental margin of a syn rift basin. The sandstones of the Kareem Formation show upward decrease in maturity. Petrographic study revealed that dolomite is the dominant cement and generally occurs as fine to medium rhombs pore occluding phase and locally as a grain replacive phase. Authigenic quartz occurs as small euhedral crystals, locally as large pyramidal crystals in the primary pores. Authigenic anhydrites typically occur as poikilotopic rhombs or elongate laths infilling pores but also as vein filling cement. The kaolinite is a by-product of feldspar leaching in the presence of acidic fluid produced during the maturation of organic matter in the adjacent Miocene rocks. Diagenetic features include compaction; dolomite, silica and anhydrite cementation with minor iron-oxide, illite, kaolinite and pyrite cements; dissolution of feldspars, rock fragments. Silica dissolution, grain replacement and

  13. Do Prosecutors Use Interview Instructions or Build Rapport with Child Witnesses?

    PubMed

    Ahern, Elizabeth C; Stolzenberg, Stacia N; Lyon, Thomas D

    2015-08-01

    This study examined the quality of interview instructions and rapport-building provided by prosecutors to 168 children aged 5-12 years testifying in child sexual abuse cases, preceding explicit questions about abuse allegations. Prosecutors failed to effectively administer key interview instructions, build rapport, or rely on open-ended narrative producing prompts during this early stage of questioning. Moreover, prosecutors often directed children's attention to the defendant early in the testimony. The productivity of different types of wh- questions varied, with what/how questions focusing on actions being particularly productive. The lack of instructions, poor quality rapport-building, and closed-ended questioning suggest that children may not be adequately prepared during trial to provide lengthy and reliable reports to their full ability. PMID:26206485

  14. Do Prosecutors Use Interview Instructions or Build Rapport with Child Witnesses?

    PubMed Central

    Ahern, Elizabeth C.; Stolzenberg, Stacia N.; Lyon, Thomas D.

    2015-01-01

    This study examined the quality of interview instructions and rapport-building provided by prosecutors to 168 children aged 5–12 years testifying in child sexual abuse cases, preceding explicit questions about abuse allegations. Prosecutors failed to effectively administer key interview instructions, build rapport, or rely on open-ended narrative producing prompts during this early stage of questioning. Moreover, prosecutors often directed children's attention to the defendant early in the testimony. The productivity of different types of wh- questions varied, with what/how questions focusing on actions being particularly productive. The lack of instructions, poor quality rapport-building, and closed-ended questioning suggest that children may not be adequately prepared during trial to provide lengthy and reliable reports to their full ability. PMID:26206485

  15. Ultra-relativistic Au+Au and d+Au collisions:

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    In this talk I will review PHOBOS data on charged particle multiplicities, obtained in Au+Au and d+Au collisions at RHIC. The general features of the Au+Au pseudorapidity distributions results will be discussed and compared to those of /line{p}p collisions. The total charged particle multiplicity, scaled by the number of participant pairs, is observed to be about 40% higher in Au+Au collisions than in /line{p}p and d+Au systems, but, surprisingly at the same level of e+e- collisions. Limiting fragmentation scaling is seen to be obeyed in Au+Au collisions.

  16. Deducing the subsurface geological conditions and structural framework of the NE Gulf of Suez area, using 2-D and 3-D seismic data

    NASA Astrophysics Data System (ADS)

    Zahra, Hesham Shaker; Nakhla, Adel Mokhles

    2015-06-01

    An interpretation of the seismic data of Ras Budran and Abu Zenima oil fields, northern central Gulf of Suez, is carried out to evaluate its subsurface tectonic setting. The structural configuration, as well as the tectonic features of the concerned area is criticized through the study of 2D and 3D seismic data interpretation with the available geological data, in which the geo-seismic depth maps for the main interesting levels (Kareem, Nukhul, Matulla, Raha and Nubia Formations) are depicted. Such maps reflect that, the Miocene structure of Ras Budran area is a nearly NE-SW trending anticlinal feature, which broken into several panels by a set of NWSE and NE-SW trending faults. The Pre-Miocene structure of the studied area is very complex, where Ras Budran area consists of step faults down stepping to the south and southwest, which have been subjected to cross faults of NE-SW trend with lateral and vertical displacements.

  17. Assessment of genetic diversity and relationships among Egyptian mango (Mangifera indica L.) cultivers grown in Suez Canal and Sinai region using RAPD markers.

    PubMed

    Mansour, Hassan; Mekki, Laila E; Hussein, Mohammed A

    2014-01-01

    DNA-based RAPD (Random Amplification of Polymorphic DNA) markers have been used extensively to study genetic diversity and relationships in a number of fruit crops. In this study, 10 (7 commercial mango cultivars and 3 accessions) mango genotypes traditionally grown in Suez Canal and Sinai region of Egypt, were selected to assess genetic diversity and relatedness. Total genomic DNA was extracted and subjected to RAPD analysis using 30 arbitrary 10-mer primers. Of these, eleven primers were selected which gave 92 clear and bright fragments. A total of 72 polymorphic RAPD bands were detected out of 92 bands, generating 78% polymorphisms. The mean PIC values scores for all loci were of 0.85. This reflects a high level of discriminatory power of a marker and most of these primers produced unique band pattern for each cultivar. A dendrogram based on Nei's Genetic distance co-efficient implied a moderate degree of genetic diversity among the cultivars used for experimentation, with some differences. The hybrid which had derived from cultivar as female parent was placed together. In the cluster, the cultivars and accessions formed separate groups according to bearing habit and type of embryo and the members in each group were very closely linked. Cluster analysis clearly showed two main groups, the first consisting of indigenous to the Delta of Egypt cultivars and the second consisting of indigenous to the Suez Canal and Sinai region. From the analysis of results, it appears the majority of mango cultivars originated from a local mango genepool and were domesticated later. The results indicated the potential of RAPD markers for the identification and management of mango germplasm for breeding purposes. PMID:24783778

  18. Accouchement de jumeaux conjoints de découverte fortuite au cours du travail au CHU de Dakar

    PubMed Central

    Guèye, Mamour; Guèye, Serigne Modou Kane; Guèye, Mame Diarra Ndiaye; Diouf, Abdoul Aziz; Niang, Mouhamadou Mansour; Diallo, Moussa; Cissé, Mamadou Lamine; Moreau, Jean Charles

    2012-01-01

    L'objectif de cette étude était de rapporter 3 cas de jumeaux conjoints, discuter de l'importance du diagnostic anténatal et de décrire les particularités diagnostiques, thérapeutiques et évolutives. Sur 45700 accouchements du 1er Février 2009 au 31 Décembre 2011, 3 cas de jumeaux conjoints ont été enregistrés, soit 1 cas pour 15000 accouchements. Ces cas ont été diagnostiqués au cours du travail au décours d'une dystocie mécanique ou d'une césarienne réalisée pour une autre indication. Il s'agissait d'un cas de jumeaux conjoints thoraco-omphalopages, un cas de diprosopes et un cas de dicéphales. L'accouchement dans les trois cas était fait par voie haute permettant d'extraire des mort-nés frais. Nous insistons sur l'intérêt d'un diagnostic anténatal précoce par le recours à l’échographie afin d’éviter les accidents mécaniques d'un accouchement qui ne saurait s'accomplir par voie basse. PMID:23133702

  19. Collective flow in Au + Au collisions

    SciTech Connect

    Ritter, H.G.; EOS Collaboration

    1994-05-01

    Based on a preliminary sample of Au + Au collisions in the EOS time projection chamber at the Bevalac, we study sideward flow as a function of bombarding energy between 0.25A GeV and 1.2A GeV. We focus on the increase in in-plane transverse momentum per nucleon with fragment mass. We also find event shapes to be close to spherical in the most central collisions, independent of bombarding energy and fragment mass up to {sup 4}He.

  20. Preservice Music Teachers' and Therapists' Nonverbal Behaviors and Their Relationship to Perceived Rapport

    ERIC Educational Resources Information Center

    Darrow, Alice-Ann; Johnson, Christopher

    2009-01-01

    The purpose of the two studies reported in the article was to determine whether or not a relationship exists between preservice music therapists' and teachers' nonverbal behaviors and their perceived rapport. In study 1, evaluators (N = 56) viewed a stimulus tape consisting of 15 45-second segments of 15 preservice music therapists leading songs…

  1. Managing Rapport in Lingua Franca Sales Negotiations: A Comparison of Professional and Aspiring Negotiators

    ERIC Educational Resources Information Center

    Planken, B.

    2005-01-01

    This article presents selective findings from a study that investigated how facework is used to achieve interpersonal goals in intercultural sales negotiations. The article reports on linguistic analyses of what Spencer-Oatey has termed ''rapport management'' which, in a negotiation context, is aimed primarily, but not exclusively, at building a…

  2. Reconsidering Rapport with Urban Teachers: Negotiating Shifting Boundaries and Legitimizing Support

    ERIC Educational Resources Information Center

    Rinke, Carol R.; Mawhinney, Lynnette

    2014-01-01

    This paper addresses Lincoln's [2010. "'What a long, strange trip it's been …': Twenty-five years of qualitative and new paradigm research." "Qualitative Inquiry" 16, no. 1: 3-9] call for greater attention to the question of rapport in qualitative research through a reflexive examination of…

  3. Saving Face: Managing Rapport in a Problem-Based Learning Group

    ERIC Educational Resources Information Center

    Robinson, Leslie; Harris, Ann; Burton, Rob

    2015-01-01

    This qualitative study investigated the complex social aspects of communication required for students to participate effectively in Problem-Based Learning and explored how these dynamics are managed. The longitudinal study of a group of first-year undergraduates examined interactions using Rapport Management as a framework to analyse communication…

  4. Who Is Controlling the Interaction? The Effect of Nonverbal Mirroring on Teacher-Student Rapport

    ERIC Educational Resources Information Center

    Jiang-yuan, Zhou; Wei, Guo

    2012-01-01

    This study investigated the effect of nonverbal mirroring on teacher-student rapport in one-on-one interactions. Nonverbal mirroring refers to the unconscious mimicry of the postures, mannerisms, facial expressions, and other behaviors of one's interaction partner in social interactions. In a within-subjects paradigm, students had four…

  5. Humor, Rapport, and Uncomfortable Moments in Interactions with Adults with Traumatic Brain Injury

    ERIC Educational Resources Information Center

    Kovarsky, Dana; Schiemer, Christine; Murray, Allison

    2011-01-01

    We examined uncomfortable moments that damaged rapport during group interactions between college students in training to become speech-language pathologists and adults with traumatic brain injury. The students worked as staff in a community-based program affiliated with a university training program that functioned as a recreational gathering…

  6. L'engelure causée par le butane commercial au cours d’un accident industriel

    PubMed Central

    Assi-Dje Bi Dje, V.; Abhe, C.M.; Sie-Essoh, J.B.; Kouamé, K.; Vilasco, B.

    2014-01-01

    Summary Les engelures sont encore exceptionnelles en Afrique sub-saharienne, mais l’essor des industries pétrochimiques en rapport avec la promotion d’une large utilisation du gaz domestique (butane commercial) expose au risque de survenue de ce type de brûlures abusivement dites gelures. Nous rapportons un cas de brûlures au froid par gaz de pétrole liquéfié (GPL) en milieu professionnel dont le diagnostic de gravité et la prise en charge tardifs ont défavorisé l’évolution locale. Le respect des mesures de sécurité au sein des usines reste néanmoins le principal moyen de prévention de ce type de brûlures méconnues. PMID:26170791

  7. Facteurs associes au port de charge céphalique chez des enfants au Bénin: étude transversale

    PubMed Central

    Akplogan, Barnabé; Hounmenou, Alain Mahoutin; Aze, Oscar; Alegbeh, Sakibou Essofa; Azondekon, Alain

    2016-01-01

    Introduction Le port de charge céphalique par les enfants est une méthode de manutention courante au Bénin. Peu d’étude sont investigué sur le port de charge céphalique chez les enfants. Méthodes Cette étude transversale vise à faire l’état des lieux et à identifier les facteurs associés au port de charge céphalique chez des enfants au Bénin. Au total,300 enfants âgés de 13,7 ± 2,6 ans ont participé à l’étude dans les 12 départements du Bénin. La méthode non probabiliste et la technique accidentelle ont été utilisées pour déterminer la taille de l’échantillon. La masse portée par les enfants constitue la variable dépendante. L’âge, la taille, les sites corporels des douleurs, l'ancienneté dans le port de charge etla fréquence hebdomadaire du port céphalique de charge constituent les variables indépendantes. Résultats Le rapport de la masse portée sur le poids corporel est évalué en moyenne à 66%. Pendant et après le port de charge, les douleurs ressenties sont localisées essentiellement au cou, au dos et au bas du dos. Le test de corrélation entre charge portée et la taille indique r = 0,58 (p < 0,001). Conclusion Cette étude indique que les enfants surchargent leur rachis lors du port de charge céphalique. PMID:27279962

  8. Palynology, palynofacies and petroleum potential of the Upper Cretaceous-Eocene Matulla, Brown Limestone and Thebes formations, Belayim oilfields, central Gulf of Suez, Egypt

    NASA Astrophysics Data System (ADS)

    El Diasty, W. Sh.; El Beialy, S. Y.; Abo Ghonaim, A. A.; Mostafa, A. R.; El Atfy, H.

    2014-07-01

    Palynological, palynofacies and organic geochemical results of 46 samples retrieved from the Upper Cretaceous - Eocene Matulla, Brown Limestone and Thebes formations, Belayim oilfields, central Gulf of Suez, Egypt are presented. The two latter formations are not dated palynologically as their lithology is not promising for palynological yield. However the Matulla Formation is dated as Turonian-Santonian age, based on the combined evidence of pollen and dinocysts. Palynofacies analysis carried out under both transmitted and fluorescent microscopy indicated that both the Thebes and Brown Limestone formations are deposited under a distal suboxic-anoxic environment. On the other hand, the Turonian-Santonian Matulla Formation supported the existence of a marginal marine deposition under dysoxic-anoxic basin to proximal suboxic-anoxic shelf environments. Rock-Eval pyrolysis and TOC results indicated that most of the studied formations are thermally immature to marginally mature and have a good petroleum potential. They are organically-rich in both oil- and gas-prone kerogen Type-II and II/III, deposited under marine reducing conditions favorable for hydrocarbon generation and expulsion.

  9. Establishing rapport: Physicians’ practice and attendees’ satisfaction at a Primary Health Care Center, Dammam, Saudi Arabia, 2013

    PubMed Central

    Al Ali, Ayat A.; Elzubair, Ahmed G.

    2016-01-01

    Background: Establishing rapport is an important step in physician–patient communication resulting in a positive effect on patient satisfaction and overall clinical outcomes. However, there is a dearth of studies on the condition of doctor–patient relations in Saudi Arabia. This study was performed to estimate the proportion of physicians who have a good rapport with patients in their practice and the proportion of satisfied attendees. Materials and Methods: A cross-sectional study was conducted at a Primary Health Care Center, Dammam, KSA. The data were collected through a structured self-administered questionnaire given to samples of attendees and physicians to estimate patient satisfaction and the practice of rapport by physicians. Results: A total of 374 attendees and 27 physicians participated in the study. The percentage of physicians who had good rapport was 51.9%. Factors that showed significant relationship with rapport practice were: Physician's age (p = 0.016), physician's experience (p = 0.043), and professional status (p = 0.031). The attendees satisfied with their physician's rapport with them were 50.5%. Factors that showed significant relationship with satisfaction were: Attendee's age (p < 0.0001), educational level (p < 0.0001), having a chronic illness (p < 0.0001), having appointment (p < 0.0001), physicians' professional status (p < 0.0001), and a nonsurgical specialty (p < 0.0001). Conclusion and Recommendation: Physicians' rapport with patients and patients' satisfaction with physicians' empathy is not high. Training is required to optimize physician–patient communication. PMID:26929724

  10. Carcinome cutané de Merkel: apport de la TEP-TDM au18FDG

    PubMed Central

    Amal, Guensi; Sara, Taleb; Ghofrane, Cherkaoui Salhi; Malika, Ait Idir; Majdouline, Houjami; Souha, Sahraoui; Abdelatif, Benider; Najoua, Touil; Ghita, Benmoussa; Zineb, Baroudi; Nabil, Chikhaoui

    2016-01-01

    Le carcinome à cellules de Merkel (CCM) est une tumeur cutanée neuroendocrinerare d’évolution imprévisible et à grand potentiel métastatique. Ce néoplasme survient habituellement chez le sujet âgé au niveau des zones photo exposées. L'avidité constante du CCM au 18 fluorodésoxyglucose (FDG) justifie l'intérêt de la tomographie par émission de positon (TEP) au cours de cette pathologie. Toutefois, aucun consensus n'est établi à ce jour. Cette étude rapporte le cas d'une patiente de 25 ans suivie pour CCM métastatique, afin d'attirer l'attention sur cette tumeur particulière et d'illustrer l'intérêt de la TEP au 18 FDG dans la prise en charge de cette entité rare. PMID:27303574

  11. Magnetic susceptibilities of liquid Cr-Au, Mn-Au and Fe-Au alloys

    SciTech Connect

    Ohno, S.; Shimakura, H.; Tahara, S.; Okada, T.

    2015-08-17

    The magnetic susceptibility of liquid Cr-Au, Mn-Au, Fe-Au and Cu-Au alloys was investigated as a function of temperature and composition. Liquid Cr{sub 1-c}Au{sub c} with 0.5 ≤ c and Mn{sub 1-c}Au{sub c} with 0.3≤c obeyed the Curie-Weiss law with regard to their dependence of χ on temperature. The magnetic susceptibilities of liquid Fe-Au alloys also exhibited Curie-Weiss behavior with a reasonable value for the effective number of Bohr magneton. On the Au-rich side, the composition dependence of χ for liquid TM-Au (TM=Cr, Mn, Fe) alloys increased rapidly with increasing TM content, respectively. Additionally, the composition dependences of χ for liquid Cr-Au, Mn-Au, and Fe-Au alloys had maxima at compositions of 50 at% Cr, 70 at% Mn, and 85 at% Fe, respectively. We compared the composition dependences of χ{sub 3d} due to 3d electrons for liquid binary TM-M (M=Au, Al, Si, Sb), and investigated the relationship between χ{sub 3d} and E{sub F} in liquid binary TM-M alloys at a composition of 50 at% TM.

  12. Electrochemistry of Au(II) and Au(III) pincer complexes: determination of the Au(II)-Au(II) bond energy.

    PubMed

    Dann, Thomas; Roşca, Dragoş-Adrian; Wright, Joseph A; Wildgoose, Gregory G; Bochmann, Manfred

    2013-10-01

    The bond energy of the unsupported Au-Au bond in the Au(ii) dimer [(C(∧)N(∧)C)Au]2 and the difference between Au(III)-OH and Au(III)-H bond enthalpies have been determined experimentally by electrochemical methods, with Au-OH and Au-H complexes showing unexpected differences in their reduction pathways, supported by DFT modelling. PMID:24051607

  13. Statistical methods and errors in family medicine articles between 2010 and 2014-Suez Canal University, Egypt: A cross-sectional study

    PubMed Central

    Nour-Eldein, Hebatallah

    2016-01-01

    Background: With limited statistical knowledge of most physicians it is not uncommon to find statistical errors in research articles. Objectives: To determine the statistical methods and to assess the statistical errors in family medicine (FM) research articles that were published between 2010 and 2014. Methods: This was a cross-sectional study. All 66 FM research articles that were published over 5 years by FM authors with affiliation to Suez Canal University were screened by the researcher between May and August 2015. Types and frequencies of statistical methods were reviewed in all 66 FM articles. All 60 articles with identified inferential statistics were examined for statistical errors and deficiencies. A comprehensive 58-item checklist based on statistical guidelines was used to evaluate the statistical quality of FM articles. Results: Inferential methods were recorded in 62/66 (93.9%) of FM articles. Advanced analyses were used in 29/66 (43.9%). Contingency tables 38/66 (57.6%), regression (logistic, linear) 26/66 (39.4%), and t-test 17/66 (25.8%) were the most commonly used inferential tests. Within 60 FM articles with identified inferential statistics, no prior sample size 19/60 (31.7%), application of wrong statistical tests 17/60 (28.3%), incomplete documentation of statistics 59/60 (98.3%), reporting P value without test statistics 32/60 (53.3%), no reporting confidence interval with effect size measures 12/60 (20.0%), use of mean (standard deviation) to describe ordinal/nonnormal data 8/60 (13.3%), and errors related to interpretation were mainly for conclusions without support by the study data 5/60 (8.3%). Conclusion: Inferential statistics were used in the majority of FM articles. Data analysis and reporting statistics are areas for improvement in FM research articles. PMID:27453839

  14. Geophysical Constraints on the Hydrogeologic and Structural Settings of the Gulf of Suez Rift-Related Basins: Case Study from the El Qaa Plain, Sinai, Egypt

    NASA Astrophysics Data System (ADS)

    Ahmed, Mohamed; Sauck, William; Sultan, Mohamed; Yan, Eugene; Soliman, Farouk; Rashed, Mohamed

    2013-11-01

    Groundwater has been identified as one of the major freshwater sources that can potentially meet the growing demands of Egypt's population. Gravity data (from 381 ground gravity stations) were collected, processed, and analyzed together with the available aeromagnetic (800 line-km) data to investigate the hydrogeologic and structural settings, areal distribution, geometry, and water storage of the aquifers in El Qaa coastal plain in the southwest Sinai Peninsula, and to assess their longevity given projected extraction rates. Findings include (1) complete Bouguer anomaly and total magnetic intensity maps show two connected sub-basins separated by a narrow saddle with an average basin length of 43 km and an average width of 12 km; (2) two-dimensional modeling of both gravity and magnetic data indicates basin fill with a maximum thickness of 3.5 km; (3) using anomalous residual gravity, the volume of water in storage was estimated at 40-56 km3; and (4) progressive increases in extraction rates over time will deplete up to 40 % of the aquifers' volume in 200-230 years and will cause the water quality to deteriorate due to seawater intrusion in 45 years. Similar geophysical exploration campaigns, if conducted over the entire coastal plains of the Red Sea and the Gulfs of Suez and Aqaba, could assist in the development of sound and sustainable management schemes for the freshwater resources in these areas. The adopted techniques could pave the way toward the establishment of sustainable utilization schemes for a much larger suite of similar aquifers worldwide.

  15. Eliciting Maltreated and Non-maltreated Children's Transgression Disclosures: Narrative Practice Rapport Building and a Putative Confession

    PubMed Central

    Lyon, Thomas D.; Wandrey, Lindsay; Ahern, Elizabeth; Licht, Robyn; Sim, Megan; Quas, Jodi A.

    2014-01-01

    This study tested the effects of narrative practice rapport building (asking open-ended questions about a neutral event) and a putative confession (telling the child an adult “told me everything that happened and he wants you to tell the truth”) on 4- to 9-year-old maltreated and nonmaltreated children's reports of an interaction with a stranger who asked them to keep toy breakage a secret (N = 264). Only one-third of children who received no interview manipulations disclosed breakage; in response to a putative confession, one-half disclosed. Narrative practice rapport building did not affect the likelihood of disclosure. Maltreated children and nonmaltreated children responded similarly to the manipulations. Neither narrative practice rapport building nor a putative confession increased false reports. PMID:24467688

  16. Magnetoresistance of Au films

    SciTech Connect

    Zhang, D. L.; Song, X. H.; Zhang, X; Zhang, Xiaoguang

    2014-01-01

    Measurement of the magnetoresistance (MR) of Au films as a function of temperature and film thickness reveals a strong dependence on grain size distribution and clear violation of the Kohler s rule. Using a model of random resistor network, we show that this result can be explained if the MR arises entirely from inhomogeneity due to grain boundary scattering and thermal activation of grain boundary atoms.

  17. Magnetoresistance of Au films

    DOE PAGESBeta

    Zhang, D. L.; Song, X. H.; Zhang, X.; Zhang, Xiaoguang

    2014-12-10

    Measurement of the magnetoresistance (MR) of Au films as a function of temperature and film thickness reveals a strong dependence on grain size distribution and clear violation of the Kohler s rule. Using a model of random resistor network, we show that this result can be explained if the MR arises entirely from inhomogeneity due to grain boundary scattering and thermal activation of grain boundary atoms.

  18. Antibacterial Au nanostructured surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-01-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies.We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It

  19. Winning Their Hearts. Members Speak Out: In performances, How do You Establish Rapport between Your Choir and Young Audiences?

    ERIC Educational Resources Information Center

    Montague, Matthew G.

    2005-01-01

    The author discusses techniques on how to establish rapport between the choir and young audiences. According to him, one of the choir's most important assets just might be something he calls access-ability. One of Webster's definitions of "access "is" permission, liberty, or ability to enter, approach, or communicate with." When it comes to…

  20. Surface morphology and optical properties of porphyrin/Au and Au/porphyrin/Au systems

    NASA Astrophysics Data System (ADS)

    Kalachyova, Yevgeniya; Lyutakov, Oleksiy; Solovyev, Andrey; Slepička, Petr; Švorčík, Vaclav

    2013-12-01

    Porphyrin/Au and Au/porphyrin/Au systems were prepared by vacuum evaporation and vacuum sputtering onto glass substrate. The surface morphology of as-prepared systems and those subjected to annealing at 160°C was studied by optical microscopy, atomic force microscopy, and scanning electron microscopy techniques. Absorption and luminescence spectra of as-prepared and annealed samples were measured. Annealing leads to disintegration of the initially continuous gold layer and formation of gold nanoclusters. An amplification of Soret band magnitude was observed on the Au/meso-tetraphenyl porphyrin (TPP) system in comparison with mere TPP. Additional enhancement of luminescence was observed after the sample annealing. In the case of sandwich Au/porphyrin/Au structure, suppression of one of the two porphyrins' luminescence maxima and sufficient enhancement of the second one were observed.

  1. Antibacterial Au nanostructured surfaces.

    PubMed

    Wu, Songmei; Zuber, Flavia; Brugger, Juergen; Maniura-Weber, Katharina; Ren, Qun

    2016-02-01

    We present here a technological platform for engineering Au nanotopographies by templated electrodeposition on antibacterial surfaces. Three different types of nanostructures were fabricated: nanopillars, nanorings and nanonuggets. The nanopillars are the basic structures and are 50 nm in diameter and 100 nm in height. Particular arrangement of the nanopillars in various geometries formed nanorings and nanonuggets. Flat surfaces, rough substrate surfaces, and various nanostructured surfaces were compared for their abilities to attach and kill bacterial cells. Methicillin-resistant Staphylococcus aureus, a Gram-positive bacterial strain responsible for many infections in health care system, was used as the model bacterial strain. It was found that all the Au nanostructures, regardless their shapes, exhibited similar excellent antibacterial properties. A comparison of live cells attached to nanotopographic surfaces showed that the number of live S. aureus cells was <1% of that from flat and rough reference surfaces. Our micro/nanofabrication process is a scalable approach based on cost-efficient self-organization and provides potential for further developing functional surfaces to study the behavior of microbes on nanoscale topographies. PMID:26648134

  2. La stigmatisation des PVVIH en Afrique: analyse de ses formes et manifestations au Burkina Faso

    PubMed Central

    Ky-Zerbo, Odette; Desclaux, Alice; Asmar, Khalil El; Makhlouf-Obermeyer, Carla; Msellati, Philippe; Somé, Jean-François

    2014-01-01

    Résumé Introduction l’impact négatif de la stigmatisation sur la prévention du VIH et la prise en charge a été documenté. La stigmatisation a été analysée au plan qualitatif au Burkina Faso, où la prévalence VIH est faible (1 %). Des mesures quantitatives sont encore nécessaires pour identifier les formes et manifestations majeures de la stigmatisation. Méthodologie dans le cadre de l’étude MATCH (Multi-country African Study on Testing and Counselling for HIV), une étude transversale a été conduite auprès de personnes ayant déjà fait le test VIH. Les personnes séropositives ont été interrogées sur les conséquences du résultat VIH+. Leur vécu de la stigmatisation a été évalué à travers 20 indicateurs de manifestations de la stigmatisation, regroupés en trois formes de stigmatisation/discrimination. Résultats au total 219 PVVIH ont été recrutées. L’autostigmatisation est la forme majeure de stigmatisation. Elle est estimée dans cette étude à 46 % comparativement à la stigmatisation dans les relations interpersonnelles évaluée à 40 % et la stigmatisation dans les services de santé qui est de 11 %. L’expérience de la stigmatisation dans les relations interpersonnelles est davantage rapportée par les PVVIH qui ont partagé leur résultat, celles qui ont un faible niveau de scolarisation, les veufs/veuves ou séparés, et les membres d’association. La stigmatisation dans les services de santé est rapportée plus souvent par les membres d’associations. Conclusion les programmes de prise en charge doivent, parallèlement à l’extension des antirétroviraux, intégrer un volet psychologique plus adapté aux besoins. Les activités d’appui psychosocial ciblant davantage l’individu doivent être développées, surtout au sein des associations. PMID:25291886

  3. Au20: A Tetrahedral Cluster

    SciTech Connect

    Li, Jun; Li, Xi; Zhai, Hua Jin; Wang, Lai S.

    2003-02-07

    Photoelectron spectroscopy revealed that a 20 atom gold cluster has an extremely large energy gap, which is even greater than that of C60, and an electron affinity comparable with that of C60. This observation suggests that the Au20 cluster must be extremely stable and chemically inert. Using relativistic density functional calculations, we found that Au20 possesses a remarkable tetrahedral structure, which is a fragment of the bulk face-centered cubic lattice of gold with a small structural relaxation. Au20 is thus a true cluster molecule, while at the same time it is exactly part of the bulk, but with very different properties. The tetrahedral Au20 may possess interesting catalytic properties and may be synthesized in bulk quantity or assembled on non-interacting surfaces.

  4. When students from different professions are co-located: the importance of interprofessional rapport for learning to work together.

    PubMed

    Croker, Anne; Fisher, Karin; Smith, Tony

    2015-01-01

    With increasing interest and research into interprofessional learning, there is scope to more deeply understand what happens when students from different professions live and study in the same location. This study aimed to explore the issue of co-location and its effects on how students learn to work with other professions. The setting for this study was a rural health education facility in Australia with close links to local health care and community services. Philosophical hermeneutics informed the research method. Interviews were undertaken with 29 participants, including students, academic educators and clinical supervisors in diagnostic radiography, medicine, nursing, nutrition and dietetics, pharmacy, physiotherapy, occupational therapy, and speech pathology. Photo-elicitation was used to facilitate participant engagement with the topic. The findings foreground the value of interprofessional rapport building opportunities for students learning to work together. Enabled by the proximity of different professions in shared educational, clinical and social spaces, interprofessional rapport building was contingent on contextual conditions (balance of professions, shared spaces and adequate time) and individual's interpersonal capabilities (being interested, being inclusive, developing interpersonal bonds, giving and receiving respect, bringing a sense of own profession and being patient-centred). In the absence of these conditions and capabilities, negative professional stereotypes may be inadvertently re-enforced. From these findings suggestions are made for nurturing interprofessional rapport building opportunities to enable students of different professions to learn to work together. PMID:25010631

  5. Perceptions of rapport across the life span: Gaze patterns and judgment accuracy.

    PubMed

    Vicaria, Ishabel M; Bernieri, Frank J; Isaacowitz, Derek M

    2015-06-01

    Although age-related deficits in emotion perception have been established using photographs of individuals, the extension of these findings to dynamic displays and dyads is just beginning. Similarly, most eye-tracking research in the person perception literature, including those that study age differences, have focused on individual attributes gleaned from static images; to our knowledge, no previous research has considered cue use in dyadic judgments with eye-tracking. The current study employed a Brunswikian lens model analysis in conjunction with eye-tracking measurements to study age differences in the judgment of rapport, a social construct comprised of mutual attentiveness, positive feelings, and coordination between interacting partners. Judgment accuracy and cue utilization of younger (n = 47) and older (n = 46) adults were operationalized as correlations between a perceiver's judgments and criterion values within a set of 34 brief interaction videos in which 2 opposite sex college students discussed a controversial topic. No age differences emerged in the accuracy of judgments; however, pathways to accuracy differed by age: Younger adults' judgments relied on some behavioral cues more than older adults. In addition, eye-tracking analyses revealed that older adults spent more time looking at the bodies of the targets in the videos, whereas younger adults spent more time looking at the targets' heads. The contributions from both the lens model and eye-tracking findings provide distinct but complementary insights to our understanding of age-related continuities and shifts in social perceptual processing. PMID:25894485

  6. Interfacial nanodroplets guided construction of hierarchical Au, Au-Pt, and Au-Pd particles as excellent catalysts

    PubMed Central

    Ma, Aijing; Xu, Jie; Zhang, Xuehua; Zhang, Bin; Wang, Dayang; Xu, Haolan

    2014-01-01

    Interfacial nanodroplets were grafted to the surfaces of self-sacrificed template particles in a galvanic reaction system to assist the construction of 3D Au porous structures. The interfacial nanodroplets were formed via direct adsorption of surfactant-free emulsions onto the particle surfaces. The interfacial nanodroplets discretely distributed at the template particle surfaces and served as soft templates to guide the formation of porous Au structures. The self-variation of footprint sizes of interfacial nanodroplets during Au growth gave rise to a hierarchical pore size distribution of the obtained Au porous particles. This strategy could be easily extended to synthesize bimetal porous particles such as Au-Pt and Au-Pd. The obtained porous Au, Au-Pt, and Au-Pd particles showed excellent catalytic activity in catalytic reduction of 4-nitrophenol. PMID:24797697

  7. Interfacial nanodroplets guided construction of hierarchical Au, Au-Pt, and Au-Pd particles as excellent catalysts.

    PubMed

    Ma, Aijing; Xu, Jie; Zhang, Xuehua; Zhang, Bin; Wang, Dayang; Xu, Haolan

    2014-01-01

    Interfacial nanodroplets were grafted to the surfaces of self-sacrificed template particles in a galvanic reaction system to assist the construction of 3D Au porous structures. The interfacial nanodroplets were formed via direct adsorption of surfactant-free emulsions onto the particle surfaces. The interfacial nanodroplets discretely distributed at the template particle surfaces and served as soft templates to guide the formation of porous Au structures. The self-variation of footprint sizes of interfacial nanodroplets during Au growth gave rise to a hierarchical pore size distribution of the obtained Au porous particles. This strategy could be easily extended to synthesize bimetal porous particles such as Au-Pt and Au-Pd. The obtained porous Au, Au-Pt, and Au-Pd particles showed excellent catalytic activity in catalytic reduction of 4-nitrophenol. PMID:24797697

  8. Impact du traitement antirétroviral sur le profil biologique des enfants VIH positifs suivis au Centre Hospitalier et Universitaire de Yaoundé au Cameroun

    PubMed Central

    Kalla, Ginette Claude Mireille; Assoumou, Marie-Claire Okomo; Kamgaing, Nelly; Monebenimp, Francisca; Mbopi-Keou, Francois-Xavier

    2015-01-01

    Introduction L'objectif de ce travail était d’évaluer l'impact du traitement antirétroviral sur le profil biologique des enfants VIH positifs suivis au Centre Hospitalier et Universitaire de Yaoundé au Cameroun. Méthodes Il s'agissait d'une étude rétrospective réalisée de Mai 2003 à Décembre 2012 au CHU de Yaoundé au Cameroun. Pour cette étude, nous avons obtenu une clairance éthique. Résultats L’âge moyen était de 54.02±46.34 mois. The sexe ratio était de 0.96 en faveur des garçons. Le diagnostic s’était fait tardivement (74.2%) ainsi que la mise sous traitement (83.3%). Seuls 36 des 116 enfants (31%) avait pu avoir un bilan biologique à l'initiation du traitement antirétroviral et six mois après l'initiation du traitement antirétroviral. Après six mois de traitement, nous avons enregistrés une augmentation significative des paramètres biologiques suivants: taux de glycémie de 0.09g/L (0.75-0.84; p= 0.007), pourcentage de CD4 chez les enfants de moins de 5 ans de 4.62% (20.12-24.75; p = 0.022), valeur absolue de CD4 chez les enfants de plus de 5 ans de 294 cellules/mm3 (151.18-445.18; p = 0.011), le rapport CD4/CD8 de 0.35 (0.55-0.90; p = 0.000). Enfin, après six mois de traitement, on enregistrait une baisse significative de la charge virale du VIH de 3.90 log (5.85-1.95; p = 0.006). Conclusion Il ressort de cette étude que la restauration immunitaire et la suppression virologique peuvent être obtenus après six mois de traitement antirétroviral. Cependant, des efforts doivent encore être faits en ce qui concerne la prise en charge du suivi biologique, gage d'un bon suivi thérapeutique au Cameroun. PMID:26113902

  9. Symmetry energy from elliptic flow in 197Au + 197Au

    NASA Astrophysics Data System (ADS)

    Russotto, P.; Wu, P. Z.; Zoric, M.; Chartier, M.; Leifels, Y.; Lemmon, R. C.; Li, Q.; Łukasik, J.; Pagano, A.; Pawłowski, P.; Trautmann, W.

    2011-03-01

    The elliptic-flow ratio of neutrons with respect to protons or light complex particles in reactions of neutron-rich systems at relativistic energies is proposed as an observable sensitive to the strength of the symmetry term in the equation of state at supra-normal densities. The results obtained from the existing FOPI/LAND data for 197Au + 197Au collisions at 400 MeV/nucleon in comparison with the UrQMD model favor a moderately soft symmetry term with a density dependence of the potential term proportional to (ρ /ρ0) γ with γ = 0.9 ± 0.4.

  10. Flow in Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Belt Tonjes, Marguerite; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wyslouch, B.

    2004-08-01

    The study of flow can provide information on the initial state dynamics and the degree of equilibration attained in heavy-ion collisions. This contribution presents results for both elliptic and directed flow as determined from data recorded by the PHOBOS experiment in Au+Au runs at RHIC at \\sqrt{s_{{\\rm NN}}} = 19.6, 130 and 200 GeV. The PHOBOS detector provides a unique coverage in pseudorapidity for measuring flow at RHIC. The systematic dependence of flow on pseudorapidity, transverse momentum, centrality and energy is discussed.

  11. Two new Myxidium species (Myxosporea: Myxidiidae) infecting the gallbladder of African flying fish, Cheilopogon nigricans and Suez fusilier, Caesio suevicus from the Red Sea, Egypt: a morphological and morphometric study.

    PubMed

    Abdel-Baki, Abdel-Azeem Sh

    2009-08-01

    Myxidium maamouni sp. n. and Myxidium aydai sp. n. were described from the gallbladder of the African flying fish Cheilopogon nigricans and Suez fusilier Caesio suevicus, respectively. Fishes were collected from the Red Sea at Al-Quseir, Egypt. M. maamouni have irregular to mostly rounded polysporous plasmodia with diameter of 27 microm. Spores were sigmoid or S-shaped and sometimes spindle-shaped in the frontal view with smooth valves. They measured 13.5 x 8.0 x 8.2 microm in size. Their polar capsules were equal pyriform and measured 7.0 x 3.2 microm in size with nine to 12 coils. Spores of M. aydai were spindle-shaped in the frontal view with thin smooth valves. They measured 23.0 x 5.6 x 5.5 microm in size. Their polar capsules were pyriform and measured 7.2 x 3.4 microm in size with eight to nine coils. PMID:19347364

  12. Universality in fragment inclusive yields from Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Insolia, A.; Tuvè, C.; Albergo, S.; Bieser, F.; Brady, F. P.; Caccia, Z.; Cebra, D.; Chacon, A. D.; Chance, J. L.; Choi, Y.; Costa, S.; Elliott, J. B.; Gilkes, M.; Hauger, J. A.; Hirsch, A. S.; Hjort, E. L.; Justice, M.; Keane, D.; Kintner, J.; Lisa, M.; Matis, H. S.; McMahan, M.; McParland, C.; Olson, D. L.; Partlan, M. D.; Porile, N. T.; Potenza, R.; Rai, G.; Rasmussen, J.; Ritter, H. G.; Romero, J. L.; Russo, G. V.; Scharenberg, R.; Scott, A.; Shao, Y.; Srivastava, B. K.; Symons, T. J. M.; Tincknell, M. L.; Wang, S.; Warren, P. G.; Wieman, H. H.; Wolf, K. L.

    2001-11-01

    The inclusive light fragment (Z⩽7) yield data in Au+Au reactions, measured by the EOS Collaboration at the LBNL Bevalac, are presented and discussed. For peripheral collisions the measured charge distributions develop progressively according to a power law which can be fitted by a single τ exponent independently of the bombarding energy in the range 250-1200 A MeV. In addition to this universal feature, we observe that the location of the maximum in the individual yields of different charged fragments shift towards lower multiplicity as the fragment charge increases from Z=3 to Z=7. This trend is common to all six measured beam energies. Moments of charge distributions and correlations among different moments are reported. Finally, the THe,DT thermometer has been constructed for central and peripheral collisions using the double yield ratios of He and D, T projectile fragments. The measured nuclear temperatures are in agreement with experimental findings in other fragmentation reactions.

  13. Global polarization measurement in Au+Au collisions

    SciTech Connect

    Abelev, B.I.; Adams, J.; Aggarwal, M.M.; Ahammed, Z.; Amonett,J.; Anderson, B.D.; Anderson, M.; Arkhipkin, D.; Averichev, G.S.; Bai,Y.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Bhardwaj, S.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L.C.; Blyth, S.-L.; Bonner, B.E.; Botje, M.; Bouchet, J.; Brandin, A.V.; Bravar, A.; Bystersky, M.; Cadman, R.V.; Cai,X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Castillo, J.; Catu,O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen,H.F.; Chen, J.H.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cosentino, M.R.; Cramer, J.G.; Crawford,H.J.; Das, D.; Das, S.; Daugherity, M.; de Moura, M.M.; Dedovich, T.G.; DePhillips, M.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Djawotho,P.; Dogra, S.M.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dunin, V.B.; Dunlop, J.C.; Dutta Mazumdar, M.R.; Eckardt, V.; Edwards, W.R.; Efimov,L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Filimonov, K.; Filip, P.; Finch,E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C.A.; Gaillard, L.; Ganti,M.S.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.S.; Gorbunov, Y.G.; Gos,H.; Grebenyuk, O.; Grosnick, D.; Guertin, S.M.; Guimaraes, K.S.F.F.; Guo,Y.; Gupta, N.; Gutierrez, T.D.; Haag, B.; Hallman, T.J.; Hamed, A.; Harris, J.W.; He, W.; Heinz, M.; Henry, T.W.; Hepplemann, S.; Hippolyte,B.; Hirsch, A.; Hjort, E.; Hoffman, A.M.; Hoffmann, G.W.; Horner, M.J.; Huang, H.Z.; Huang, S.L.; Hughes, E.W.; Humanic, T.J.; Igo, G.; Jacobs,P.; Jacobs, W.W.; Jakl, P.; Jia, F.; Jiang, H.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Khodyrev,V.Yu.; Kim, B.C.; Kiryluk, J.; Kisiel, A.; Kislov, E.M.; Klein,S.R.; Kocoloski, A.; Koetke, D.D.; et al.

    2007-08-02

    The system created in non-central relativisticnucleus-nucleus collisions possesses large orbital angular momentum. Dueto spin-orbit coupling, particles produced in such a system could becomeglobally polarized along the direction of the system angular momentum. Wepresent the results of Lambda and anti-Lambda hyperon global polarizationmeasurements in Au+Au collisions at sqrt sNN=62.4 GeV and 200 GeVperformed with the STAR detector at RHIC. The observed globalpolarization of Lambda and anti-Lambda hyperons in the STAR acceptance isconsistent with zero within the precision of the measurements. Theobtained upper limit, lbar P Lambda, anti-Lambda rbar<= 0.02, iscompared to the theoretical values discussed recently in theliterature.

  14. Nuclear Modification of Jet Fragmentation in Au+Au Collisions

    NASA Astrophysics Data System (ADS)

    Rowan, Zachary; Phenix Collaboration

    2015-10-01

    The characterization of energy in the quark gluon plasma is facilitated by measurements of modifications to the observed jet fragmentation. A favorable channel of study relies on direct photons created in the initial parton interactions of heavy ion collisions. Such a photon traverses the created medium unscathed and grants us a proxy for the transverse momentum of an away side jet. PHENIX Au+Au data recorded at √{sNN} = 200 GeV during RHIC run 14 benefit from the background rejection capability of the silicon vertex detector, enabling the extraction of a higher purity hadron signal. This advantage, combined with a larger integrated luminosity, allows previous PHENIX measurements of fragmentation functions to be extended to greater jet energies. In this talk, the status of the analysis of direct photon hadron correlations with the new data set will be discussed.

  15. Global polarization measurement in Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Belaga, V. V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Blyth, S.-L.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Brandin, A. V.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Moura, M. M. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; Didenko, L.; Dietel, T.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunin, V. B.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C. A.; Gaillard, L.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gos, H.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Henry, T. W.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Horner, M. J.; Huang, H. Z.; Hughes, E. W.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kiryluk, J.; Kisiel, A.; Kislov, E. M.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kowalik, K. L.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Kuhn, C.; Kulikov, A. I.; Kumar, A.; Kurnadi, P.; Kuznetsov, A. A.; Lamont, M. A. C.; Landgraf, J. M.; Lange, S.; Lapointe, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lehocka, S.; Levine, M. J.; Li, C.; Li, Q.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, J. G.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Martin, L.; Matis, H. S.; Matulenko, Yu. A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mitchell, J.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Olson, D.; Pachr, M.; Pal, S. K.; Panebratsev, Y.; Pavlinov, A. I.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Porile, N.; Poskanzer, A. M.; Potekhin, M.; Potrebenikova, E.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Qattan, I. A.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Relyea, D.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Sazhin, P. S.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shen, W. Q.; Shimanskiy, S. S.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Z.; Surrow, B.; Symons, T. J. M.; Toledo, A. Szanto De; Takahashi, J.; Tang, A. H.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Timoshenko, S.; Tokarev, M.; Trainor, T. A.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; Kolk, N. Van Der; Leeuwen, M. Van; Molen, A. M. Vander; Varma, R.; Vasilevski, I. M.; Vasiliev, A. N.; Vernet, R.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, X. L.; Wang, Y.; Webb, J. C.; Westfall, G. D.; , C. Whitten, Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, J.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Yurevich, V. I.; Zawisza, M.; Zhan, W.; Zhang, H.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zubarev, A. N.; Zuo, J. X.

    2007-08-01

    The system created in noncentral relativistic nucleus-nucleus collisions possesses large orbital angular momentum. Because of spin-orbit coupling, particles produced in such a system could become globally polarized along the direction of the system angular momentum. We present the results of Λ and Λ¯ hyperon global polarization measurements in Au+Au collisions at sNN=62.4 and 200 GeV performed with the STAR detector at the BNL Relativistic Heavy Ion Collider (RHIC). The observed global polarization of Λ and Λ¯ hyperons in the STAR acceptance is consistent with zero within the precision of the measurements. The obtained upper limit, |PΛ,Λ¯|⩽0.02, is compared with the theoretical values discussed recently in the literature.

  16. d + Au hadron correlation measurements at PHENIX

    SciTech Connect

    Anne M. Sickles

    2014-05-13

    In these proceedings, we discuss recent results from d + Au collisions in PHENIX ridge related measurements and their possible hydrodynamic origin. We present the v2 at midrapidity and measurements of the pseudorapidity dependence of the ridge, distinguishing between the d-going and Au-going directions. We investigate the possible geometrical origin by comparing v2 in d + Au to that in p + Pb, Au + Au and Pb + Pb collisions. Future plans to clarify the role of geometry in small collision systems at RHIC are discussed.

  17. Cometary Activity Beyond 4 AU

    NASA Astrophysics Data System (ADS)

    Womack, M.

    2000-10-01

    Recent observations of the distantly active comets 29 P/Schwassmann-Wachmann 1, 2060 Chiron, and C/1995 O1 (Hale-Bopp) are consistent with models that predict that the activity beyond 4 AU is dominated by outgassing of CO and CO2 molecules trapped in an amorphous water ice surface undergoing crystallization. The nominal CO production rates in Hale-Bopp, SW 1 and Chiron over the range of r = 4 to 9 AU are consistent with Q(CO) = (2.9+/-0.5)x1030r{(-2.5 +/- 0.1)}, with sporadic outbursts superimposed. The data indicate that the gas production rates in distant comets are primarily determined by the composition, and not the size, of the nucleus. The dust production rates, however, are very different among these comets and are not well-correlated with heliocentric distance. Thus, the gas and dust mixtures may not be uniform amongst these comets, nor in an individual comet. Development and sublimation of an icy grain coma at ~ 5 AU appears to be a common feature in distantly active comets. Sublimation of such icy grains is probably the main source of emission of OH, CH3OH, HCN, and H2S in comets beyond 4 AU. Studying the energetics of these phenomena provides an excellent opportunity to learn more about the composition and physical behavior of comet nuclei, as well as other icy bodies in the outer solar system, such as moons and Kuiper Belt Objects. This work was funded by the NSF CAREER Program.

  18. Synthesis and optical property characterization of elongated AuPt and Pt@Au metal nanoframes

    NASA Astrophysics Data System (ADS)

    Lee, Sangji; Jang, Hee-Jeong; Jang, Ho Young; Hong, Soonchang; Moh, Sang Hyun; Park, Sungho

    2016-02-01

    We report a facile method to synthesize elongated nanoframes consisting of Pt and Au in solution. Pentagonal Au nanorods served as templates and successfully led to an elongated AuPt nanoframe after etching the core Au. Subsequently, the coating of Au around Pt ridges resulted in Pt@Au metal nanoframes. The resulting elongated nanostructure exhibited 5 well-defined ridges continuously connected along the long axis. During the shape evolution from pure Au nanorods to elongated Pt@Au metal nanoframes, their corresponding localized surface plasmon resonance bands were monitored. Especially, unique surface plasmon features were observed for elongated Pt@Au nanoframes where the short-axis oscillation of surface free electrons is strongly coupled but the long-axis oscillation is not coupled among the ridges.We report a facile method to synthesize elongated nanoframes consisting of Pt and Au in solution. Pentagonal Au nanorods served as templates and successfully led to an elongated AuPt nanoframe after etching the core Au. Subsequently, the coating of Au around Pt ridges resulted in Pt@Au metal nanoframes. The resulting elongated nanostructure exhibited 5 well-defined ridges continuously connected along the long axis. During the shape evolution from pure Au nanorods to elongated Pt@Au metal nanoframes, their corresponding localized surface plasmon resonance bands were monitored. Especially, unique surface plasmon features were observed for elongated Pt@Au nanoframes where the short-axis oscillation of surface free electrons is strongly coupled but the long-axis oscillation is not coupled among the ridges. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08200e

  19. Errorless Embedding for Children with On-Task and Conduct Difficulties: Rapport-Based, Success-Focused Intervention in the Classroom

    ERIC Educational Resources Information Center

    Ducharme, Joseph M.; Harris, Kimberly E.

    2005-01-01

    Children exposed to psychosocial stressors often develop behavior disorders that include off-task responding in the classroom. We used errorless embedding, a rapport-based, nonpunitive intervention, to improve on-task behavior in such children. In a multiple-baseline across subjects design, we observed 5 children with severe behavioral…

  20. A + (B[subscript 1]) Professor--student Rapport + (B[subscript 2]) Humor + (B[subscript 3]) Student Engagement = (Y) Student Ratings of Instructors

    ERIC Educational Resources Information Center

    Richmond, Aaron S.; Berglund, Majken B.; Epelbaum, Vadim B.; Klein, Eric M.

    2015-01-01

    Teaching effectiveness is often evaluated through student ratings of instruction (SRI). Research suggests that there are many potential factors that can predict student's perceptions of teaching effectiveness such as professor-student rapport, student engagement, and perceived humor of the instructor. Therefore, we sought to assess whether…

  1. Etude séro-épidémiologique de la leishmaniose canine au centre du Maroc

    PubMed Central

    Fellah, Hajiba; Doughmi, Oursula; Maniar, Saâd; Lalami, Abdelhakim El Ouali

    2014-01-01

    Dans le monde, la leishmaniose viscérale humaine est connue pour avoir comme principale source d'infection les Canidés domestiques et sauvages. Au centre du Maroc, les données épidémiologiques, cliniques et parasitologiques sur la leishmaniose canine, sont quasiment inexistantes. Ce travail traite une étude prospective au cours de laquelle 61 sérums canins ont été analysés par un test rapide et par l'immunofluorescence indirecte. La sensibilité du test rapide par rapport à celle de l'immunofluorescence indirecte (IFI) est de 33,33%. La fréquence de la maladie chez les chiens s’élève à 9,83% (Test Rapide) et 24,59% (IFI). 73,33% des cas canins positifs à la sérologie sont asymptomatiques. Ce sont les jeunes chiens de moins de 5 ans qui sont les plus fréquemment atteints avec une sensibilité de la race Berger Allmand à l'infection. Cette étude a permis de mettre en évidence la présence de chiens leishmaniens (15 chiens séropositifs parmi 61) et de prouver l'existence du réservoir canin. Une stratégie de prévention active doit être mise en place. PMID:25852791

  2. Arthropathie destructrice des épaules au cours d'une acromégalie

    PubMed Central

    Akasbi, Nessrine; Tahiri, Latifa; Lyhyaoui, Ouafae; Elidrissi, Mohammed; Sqalli Houssaini, Ghita; Elmrini, Abdelmajid; Ajdi, Farida; Taoufik, Harzy

    2011-01-01

    L'acromégalie est une maladie endocrinienne rare, en rapport avec une hypersécrétion d'hormone de croissance. Elle a des conséquences rhumatologiques: l'arthropathie périphérique, l'atteinte rachidienne et les syndromes canalaires. L'atteinte articulaire accompagne une acromégalie active, sa survenue après un traitement radical et une rémission complète est rare. Nous présentons le cas d'une patiente de 70 ans ayant un antécédent d'acromégalie sur adénome hypophysaire il y a 25 ans, traitée chirurgicalement et déclarée en rémission complète, a développé une arthropathie destructrice des deux épaules. Le but de notre observation est de mettre le point sur la possibilité d'une atteinte articulaire au cours de l'acromégalie et de son retentissement fonctionnelle. PMID:22187594

  3. New Strategies To Combat Long-Term Unemployment in Belgium, Denmark and the United Kingdom. Synthesis Report = Nouvelles strategies de lutte contre le chomage de longue duree en Belgigue, au Danemark, et au Royaume-Uni. Rapport de synthese.

    ERIC Educational Resources Information Center

    Geers, Frederik; And Others

    This synthesis report provides information to policy makers, practitioners, and researchers on the new strategies and measures adopted in Belgium, Denmark, and the United Kingdom to combat long-term unemployment. It begins with a summary of strategies and measures adopted in each of the three countries. Each country report highlights the following…

  4. Wetting and energetics of solid Au and Au-Ge/SiC interfaces

    SciTech Connect

    Wang, Z.; Wynblatt, P.

    1998-09-01

    A solid state wetting technique has been used to investigate the effects of alloying Au with Ge on the wetting and energetics of Au/SiC interfaces at 1123 K. Germanium was found to segregate to the Au/SiC interface, thereby lowering the contact angle of Au on SiC from 133 to 110, and doubling the work of adhesion of Au on SiC. Calculations based on a monolayer model predict a segregation of 0.89 monolayers of Ge at the Au/SiC interface for Au containing 2.3 at.% Ge. This agrees reasonably well with a coverage of 0.6 monolayers Ge at the Au/SiC interface obtained by direct measurements based on the crater edge profiling technique. The work also demonstrates that simple models of interfacial composition can be combined with the Gibbs adsorption isotherm to provide reliable estimates of interfacial composition at complex four-component interfaces.

  5. Gold nanowired: a linear (Au25)(n) polymer from Au25 molecular clusters.

    PubMed

    De Nardi, Marco; Antonello, Sabrina; Jiang, De-en; Pan, Fangfang; Rissanen, Kari; Ruzzi, Marco; Venzo, Alfonso; Zoleo, Alfonso; Maran, Flavio

    2014-08-26

    Au25(SR)18 has provided fundamental insights into the properties of clusters protected by monolayers of thiolated ligands (SR). Because of its ultrasmall core, 1 nm, Au25(SR)18 displays molecular behavior. We prepared a Au25 cluster capped by n-butanethiolates (SBu), obtained its structure by single-crystal X-ray crystallography, and studied its properties both experimentally and theoretically. Whereas in solution Au25(SBu)18(0) is a paramagnetic molecule, in the crystal it becomes a linear polymer of Au25 clusters connected via single Au-Au bonds and stabilized by proper orientation of clusters and interdigitation of ligands. At low temperature, [Au25(SBu)18(0)]n has a nonmagnetic ground state and can be described as a one-dimensional antiferromagnetic system. These findings provide a breakthrough into the properties and possible solid-state applications of molecular gold nanowires. PMID:25088331

  6. Pt{sub 3}Au and PtAu clusters: Electronic states and potential energy surfaces

    SciTech Connect

    Dai, D.; Balasubramanian, K.

    1994-03-15

    We carried out complete active space multiconfiguration self-consistent-field calculations followed by multireference singles+doubles configuration interaction with the Davidson correction which included up to 3.55 million configurations employing relativistic effective core potentials on Pt{sub 3}+Au and PtAu clusters. Four low-lying electronic states were identified for Pt{sub 3}+Au. The {sup 2}{ital A}{sub 2} electronic state ({ital C}{sub 3{ital v}}) was found to be the ground state of Pt{sub 3}Au. Spin--orbit effects were found to be significant. We also computed six low-lying electronic states of PtAu and four low-lying electronic states of PtAu{sup +}. The 5/2 ({sup 2}{Delta}) and 0{sup +}({sup 1}{Sigma}{sup +}) states were found to be the ground states of PtAu and PtAu{sup +}, respectively.

  7. Interplanetary dust between 1 and 5 AU

    NASA Technical Reports Server (NTRS)

    Stanley, J. E.; Singer, S. F.; Alvarez, J. M.

    1979-01-01

    Analyses of data from the Meteoroid Detection Experiment (MDE) and the Imaging Photopolarimeter (IPP) aboard Pioneer 10 and 11 have led to contradictory conclusions. While the MDE indicates a significant particle environment in the outer solar system (out to at least 5 AU), the IPP sees no zodiacal light (therefore implying no small particles) past 3.3 AU. These two results are reconciled by noting that the spectral index p (relating particle radius and particle concentration) is not a constant in the solar system but changes from less than 2 near 1 AU to more than 2.5 at 5 AU for particles in the range of 10 microns.

  8. Bright, NIR-emitting Au23 from Au25: characterization and applications including biolabeling.

    PubMed

    Muhammed, Madathumpady Abubaker Habeeb; Verma, Pramod Kumar; Pal, Samir Kumar; Kumar, R C Arun; Paul, Soumya; Omkumar, Ramakrishnapillai Vyomakesannair; Pradeep, Thalappil

    2009-10-01

    A novel interfacial route has been developed for the synthesis of a bright-red-emitting new subnanocluster, Au(23), by the core etching of a widely explored and more stable cluster, Au(25)SG(18) (in which SG is glutathione thiolate). A slight modification of this procedure results in the formation of two other known subnanoclusters, Au(22) and Au(33). Whereas Au(22) and Au(23) are water soluble and brightly fluorescent with quantum yields of 2.5 and 1.3 %, respectively, Au(33) is organic soluble and less fluorescent, with a quantum yield of 0.1 %. Au(23) exhibits quenching of fluorescence selectively in the presence of Cu(2+) ions and it can therefore be used as a metal-ion sensor. Aqueous- to organic-phase transfer of Au(23) has been carried out with fluorescence enhancement. Solvent dependency on the fluorescence of Au(23) before and after phase transfer has been studied extensively and the quantum yield of the cluster varies with the solvent used. The temperature response of Au(23) emission has been demonstrated. The inherent fluorescence of Au(23) was used for imaging human hepatoma cells by employing the avidin-biotin interaction. PMID:19711391

  9. The Electronic Properties and L3 XANES of Au and Nano-Au

    SciTech Connect

    Yiu, Y.M.; Zhang, P.; Sham, T.K.

    2004-04-20

    The electronic properties of Au crystal and nano Au have been investigated by theory and experiment. Molecularly capped nano-Au was synthesized using the two-phase method. Au nano-particles have been characterized by X-Ray Diffraction (XRD) and Transmission Electron Microscopy (TEM). They retain the fcc crystal structure. Their sizes have been determined to be in a range from 5.5 nm to 1.7 nm. The L3 X-ray Absorption Near Edge Structure (XANES) of nano-Au and Au foil have been recorded using synchrotron radiation, and examined by theoretical calculation based on the first principles. Both theory and experiment show that the nano-Au particles have essentially all the Au L3 XANES features of bulk Au in the near edge region with less pronounced resonance peaks. It is also shown that nano Au exhibits lower 4f binding energy than bulk Au in good agreement with quantum confined Au systems reported previously.

  10. Au nanorod helical superstructures with designed chirality.

    PubMed

    Lan, Xiang; Lu, Xuxing; Shen, Chenqi; Ke, Yonggang; Ni, Weihai; Wang, Qiangbin

    2015-01-14

    A great challenge for nanotechnology is to controllably organize anisotropic nanomaterials into well-defined three-dimensional superstructures with customized properties. Here we successfully constructed anisotropic Au nanorod (AuNR) helical superstructures (helices) with tailored chirality in a programmable manner. By designing the 'X' pattern of the arrangement of DNA capturing strands (15nt) on both sides of a two-dimensional DNA origami template, AuNRs functionalized with the complementary DNA sequences were positioned on the origami and were assembled into AuNR helices with the origami intercalated between neighboring AuNRs. Left-handed (LH) and right-handed (RH) AuNR helices were conveniently accomplished by solely tuning the mirrored-symmetric 'X' patterns of capturing strands on the origami. The inter-rod distance was precisely defined as 14 nm and inter-rod angle as 45°, thus a full helix contains 9 AuNRs with its length up to about 220 nm. By changing the AuNR/origami molar ratio in the assembly system, the average number of AuNR in the helices was tuned from 2 to 4 and 9. Intense chiroptical activities arose from the longest AuNR helices with a maximum anisotropy factor of ∼0.02, which is highly comparable to the reported macroscopic AuNR assemblies. We expect that our strategy of origami templated assembly of anisotropic chiral superstructures would inspire the bottom-up fabrication of optically active nanostructures and shed light on a variety of applications, such as chiral fluids, chiral signal amplification, and fluorescence combined chiral spectroscopy. PMID:25516475

  11. Oxygen-assisted reduction of Au species on Au/SiO2 catalyst in room temperature CO oxidation

    SciTech Connect

    Wu, Zili; Zhou, Shenghu; Zhu, Haoguo; Dai, Sheng; Overbury, Steven {Steve} H

    2008-01-01

    An unexpected oxygen-assisted reduction of cationic Au species by CO was found on a Au/SiO2 catalyst at room temperature; CO oxidation activity increases simultaneously with the reduction of Au species, suggesting the key role of metallic Au played in CO oxidation on Au/SiO2.

  12. Facteurs de risque de l'infection par le VIH dans le district de santé de Meyomessala au Cameroun

    PubMed Central

    Mbopi-Keou, Francois-Xavier; Nguefack-Tsague, Georges; Kalla, Ginette Claude Mireille; Abessolo, Stéphanie Abo'o; Angwafo, Fru; Muna, Walinjom

    2014-01-01

    Introduction L'objectif de ce travail était de déterminer les facteurs de risque de l'infection par le VIH dans le district de santé de Meyomessala (Région du Sud) au Cameroun. Méthodes Il s'agissait d'une étude transversale, descriptive et analytique qui s'est déroulée de Février à Mai 2011. Pour cette étude, nous avons obtenu une clairance éthique. Résultats L’échantillon était constitué de 315 participants dont 181 (57,46%) hommes et 134 (42,54%) femmes. L’âge moyen était de 24,5±8ans (extrême: 15-45ans). Quarante personnes (40) étaient séropositifs, soit une prévalence de l'infection par le VIH de 12,7%. Cette prévalence augmentait significativement (p = 0) avec le nombre de partenaires occasionnels au cours des douze derniers mois, allant de 2,7% chez ceux n'ayant eu aucun partenaire occasionnel à 21,25% chez ceux ayant plus de trois partenaires occasionnels (RC = 9,72; IC = 1,27-74,14; P = 0,03). le fait d’être âgé entre 20 et 24 ans (RC = 4,88; IC = 1,74-13,67; p = 0), avoir plus de trois partenaires sexuels au cours des douze derniers mois (RC = 9,72; IC = 1,27-74,14; p = 0,03), avoir les rapports sexuels avec les prostitués (RC = 2,86; IC = 1,42-5,76; p = 0), avoir eu le chlamydia (RC = 3,00; IC = 1,07-8,39; p = 0,04), avoir eu la syphilis (RC = 3,35; IC = 1,57-7,14; p = 0), avoir des avantages sociaux lors du premier rapport sexuel (RC = 2,57; IC = 1,03-6,43; p = 0,04) constituaient des potentiels facteurs de risque du VIH. Conclusion Il apparait urgent d'intensifier les campagnes de sensibilisation au risque d'infection par le VIH et les maladies sexuellement transmissibles dans le district de santé de Meyomessala PMID:25419299

  13. [(CF3)4Au2(C5H5N)2]--a new alkyl gold(II) derivative with a very short Au-Au bond.

    PubMed

    Zopes, David; Hegemann, Corinna; Tyrra, Wieland; Mathur, Sanjay

    2012-09-11

    A new gold(II) species [(CF(3))(4)Au(2)(C(5)H(5)N)(2)] with a very short unsupported Au-Au bond (250.62(9) pm) was generated by photo irradiation of a silver aurate, [Ag(Py)(2)][Au(CF(3))(2)], unambiguously characterized by (19)F and (109)Ag NMR studies. PMID:22836874

  14. Thermal and photoinduced reduction of ionic Au(III) to elemental Au nanoparticles by dissolved organic matter in water: possible source of naturally occurring Au nanoparticles.

    PubMed

    Yin, Yongguang; Yu, Sujuan; Liu, Jingfu; Jiang, Guibin

    2014-01-01

    Naturally occurring Au nanoparticles (AuNPs) have been widely observed in ore deposits, coal, soil, and environmental water. Identifying the source of these naturally occurring AuNPs could be helpful for not only the discovery of Au deposits through advanced exploration methods, but also the elucidation of the biogeochemical cycle and environmental toxicity of ionic Au and engineered AuNPs. Here, we investigated the effect of natural/simulated sunlight and heating on the reduction of ionic Au by ubiquitous dissolved organic matter (DOM) in river water. The reductive process probed by X-ray photoelectron spectroscopy revealed that phenolic, alcoholic, and aldehyde groups in DOM act as reductive sites. Long-time exposure with thermal and photoirradiation induced the further fusion and growth of AuNPs to branched Au nanostructure as precipitation. The formation processes and kinetics of AuNPs were further investigated using humic acid (HA) as the DOM model, with comprehensive characterizing methods. We have observed that HA can reduce ionic Au(III) complex (as chloride or hydroxyl complex) to elemental Au nanoparticles under sunlight or heating. In this process, nearly all of the Au(III) could be reduced to AuNPs, in which HA serves as not only the reductive agent, but also the coating agent to stabilize and disperse AuNPs. The size and stability of AuNPs were highly dependent on the concentration ratio of Au(III) to HA. These results imply that, besides biological processes, this thermal or photochemical reduction process is another possible source of naturally occurring AuNPs in natural environments, which possibly has critical impacts on the transport and transformation of Au and engineered AuNPs. PMID:24471802

  15. Self-assembly of thiolated cyanine aggregates on Au(111) and Au nanoparticle surfaces

    NASA Astrophysics Data System (ADS)

    Menéndez, Guillermo O.; Cortés, Emiliano; Grumelli, Doris; Méndez de Leo, Lucila P.; Williams, Federico J.; Tognalli, Nicolás G.; Fainstein, Alejandro; Vela, María Elena; Jares-Erijman, Elizabeth A.; Salvarezza, Roberto C.

    2012-01-01

    Heptamethinecyanine J-aggregates display sharp, intense fluorescence emission making them attractive candidates for developing a variety of chem-bio-sensing applications. They have been immobilized on planar thiol-covered Au surfaces and thiol-capped Au nanoparticles by weak molecular interactions. In this work the self-assembly of novel thiolated cyanine (CNN) on Au(111) and citrate-capped AuNPs from solutions containing monomers and J-aggregates has been studied by using STM, XPS, PM-IRRAS, electrochemical techniques and Raman spectroscopy. Data show that CNN species adsorb on the Au surfaces by forming thiolate-Au bonds. We found that the J-aggregates are preferentially adsorbed on the Au(111) surface directly from the solution while adsorbed CNN monomers cannot organize into aggregates on the substrate surface. These results indicate that the CNN-Au interaction is not able to disorganize the large J-aggregates stabilized by π-π stacking to optimize the S-Au binding site but it is strong enough to hinder the π-π stacking when CNNs are chemisorbed as monomers. The optical properties of the J-aggregates remain active after adsorption. The possibility of covalently bonding CNN J-aggregates to Au planar surfaces and Au nanoparticles controlling the J-aggregate/Au distance opens a new path regarding their improved stability and the wide range of biological applications of both CNN and AuNP biocompatible systems.Heptamethinecyanine J-aggregates display sharp, intense fluorescence emission making them attractive candidates for developing a variety of chem-bio-sensing applications. They have been immobilized on planar thiol-covered Au surfaces and thiol-capped Au nanoparticles by weak molecular interactions. In this work the self-assembly of novel thiolated cyanine (CNN) on Au(111) and citrate-capped AuNPs from solutions containing monomers and J-aggregates has been studied by using STM, XPS, PM-IRRAS, electrochemical techniques and Raman spectroscopy. Data show

  16. Photoionization of Au+, Au2+, and Au3+ ions and developments in the synthesis of the metallofullerene Au@C60

    NASA Astrophysics Data System (ADS)

    Kilcoyne, A. L. David; Muller, Alfred; Schippers, Stefan; Hellhund, Jonas; Borovik, Alexander; Mueller, Allison; Gross, Dylan; Johnson, Andrea; Macaluso, David; A. L. D. Kilcoyne Collaboration

    2015-05-01

    Absolute single photoionization of Au+, Au2+, and Au3+ ions was investigated via the merged-beams technique at AMO Beamline 10.0.1.2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. The absolute single photoionization yield was measured as a function of photon energy for each species from the metastable state ionization threshold region to well above the ground state ionization potential. Additional high-resolution measurements were performed for Au+ and Au2+ ions in the region of the ground and metastable state ionization thresholds to better resolve the detailed resonant structure found therein. This structure was used, along with the reported excited state energy levels of Au+, to preliminarily identify previously unreported excitation levels in all three ions. In addition and as a component of the same program, photoionization studies of the endohedral metallofullerene Au@C60+were performed using endohedral fullerene samples synthesized on-site at Beamline 10.0.1.2 of the ALS.

  17. Volcano-sedimentary characteristics in the Abu Treifiya Basin, Cairo-Suez District, Egypt: Example of dynamics and fluidization over sedimentary and volcaniclastic beds by emplacement of syn-volcanic basaltic rocks

    NASA Astrophysics Data System (ADS)

    Khalaf, E. A.; Abdel Motelib, A.; Hammed, M. S.; El Manawi, A. H.

    2015-12-01

    This paper describes the Neogene lava-sediment mingling from the Abu Treifiya Basin, Cairo-Suez district, Egypt. The lava-sediment interactions as peperites have been identified for the first time at the study area and can be used as paleoenvironmental indicators. The identification of peperite reflects contemporaneous time relationship between volcanism and sedimentation and this finding is of primary importance to address the evolutional reconstruction of the Abu Treifiya Basin. Characterization of the facies architecture and textural framework of peperites was carried out through detailed description and interpretation of their outcrops. The peperites and sedimentary rocks are up to 350 m thick and form a distinct stratigraphic framework of diverse lithology that is widespread over several kilometers at the study area. Lateral and vertical facies of the peperites vary from sediment intercalated with the extrusive/intrusive basaltic rocks forming peperitic breccias to lava-sediment contacts at a large to small scales, respectively. Peperites encompass five main facies types ascribed to: (i) carbonate sediments-hosted fluidal and blocky peperites, (ii) lava flow-hosted blocky peperites, (iii) volcaniclastics-hosted fluidal and blocky peperites, (iv) sandstone/siltstone rocks-hosted blocky peperites, and (iv) debris-flows-hosted blocky peperites. Soft sediment deformation structures, vesiculated sediments, sediments filled-vesicles, and fractures in lava flows indicate that lava flows mingled with unconsolidated wet sediments. All the peperites in this study could be described as blocky or fluidal, but mixtures of different clast shapes occur regardless of the host sediment. The presence of fluidal and blocky juvenile clasts elucidates different eruptive styles, reflecting a ductile and brittle fragmentation. The gradual variation from fluidal to blocky peperite texture, producing the vertical grading is affected by influencing factors, e.g., the viscosity, magma

  18. Controlled Synthesis of Au@AgAu Yolk-Shell Cuboctahedra with Well-Defined Facets.

    PubMed

    Londono-Calderon, Alejandra; Bahena, Daniel; Yacaman, Miguel J

    2016-08-01

    The synthesis of Au@AgAu yolk-shell cuboctahedra nanoparticles formed by galvanic replacement in a seed-mediated method is described. Initially, single-crystal Au seeds are used for the formation of Au@Ag core-shell nanocubes, which serve as the template material for the deposition of an external Au layer. The well-controlled synthesis yields the formation of cuboctahedra nanoparticles with smooth inner and outer Au/Ag surfaces. The deposition/oxidation process is described to understand the formation of cuboctahedra and octahedra nanoparticles. The Au core maintains the initial morphology of the seed and remains static at the center of the yolk-shell because of residual Ag. Structural analysis of the shell indicates intrinsic stacking faults (SFs) near the surface. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) compositional analysis show an Au-Ag nonordered alloy forming the shell. The three-dimensional structure of the nanoparticles presented open facets on the [111] as observed by electron tomography SIRT reconstruction over a stack of high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images. The geometrical model was validated by analyzing the direction of streaks in coherent nanobeam diffraction (NBD). The catalytic activity was evaluated using a model reaction based on the reduction of 4-nitrophenol (4-NTP) by NaBH4 in the presence of Au@AgAu yolk-shell nanoparticles. PMID:27385583

  19. Au40: A large tetrahedral magic cluster

    NASA Astrophysics Data System (ADS)

    Jiang, De-En; Walter, Michael

    2011-11-01

    40 is a magic number for tetrahedral symmetry predicted in both nuclear physics and the electronic jellium model. We show that Au40 could be such a a magic cluster from density functional theory-based basin hopping for global minimization. The putative global minimum found for Au40 has a twisted pyramid structure, reminiscent of the famous tetrahedral Au20, and a sizable HOMO-LUMO gap of 0.69 eV, indicating its molecular nature. Analysis of the electronic states reveals that the gap is related to shell closings of the metallic electrons in a tetrahedrally distorted effective potential.

  20. Au40: A Large Tetrahedral Magic Cluster

    SciTech Connect

    Jiang, Deen; Walter, Michael

    2011-01-01

    40 is a magic number for tetrahedral symmetry predicted in both nuclear physics and the electronic jellium model. We show that Au{sub 40} could be such a magic cluster from density functional theory-based basin hopping for global minimization. The putative global minimum found for Au{sub 40} has a twisted pyramid structure, reminiscent of the famous tetrahedral Au{sub 20}, and a sizable HOMO-LUMO gap of 0.69 eV, indicating its molecular nature. Analysis of the electronic states reveals that the gap is related to shell closings of the metallic electrons in a tetrahedrally distorted effective potential.

  1. d + Au hadron correlation measurements from PHENIX

    NASA Astrophysics Data System (ADS)

    Sickles, Anne M.

    2015-01-01

    Recent observations of extended pseudorapidity correlations at the LHC in p+p and p+Pb collisions are of great interest. Here we present related results from d+Au collisions at PHENIX. We present the observed v2 and discuss the possible origin in the geometry of the collision region. We also present new measurements of the pseudorapidity dependence of the ridge in d+Au collision. Future plans to clarify the role of geometry in small collision systems using 3 He + Au collisions are discussed.

  2. Au, Ge and AuGe Nanoparticles Fabricated by Laser Ablation

    SciTech Connect

    Musaev, O.R.; Sutter, E.; Wrobel, J.M.; Kruger, M.B.

    2012-02-01

    A eutectic AuGe target immersed in distilled water was ablated by pulsed ultraviolet laser light. The structure of the ablated material was investigated by high-resolution transmission electron microscopy (HRTEM). The images show formation of nanowire structures of AuGe up to 100 nm in length, with widths of 5-10 nm. These nanostructures have Ge content significantly lower than the target material. Electron diffraction demonstrates that they crystallize in the {alpha}-AuGe structure. For comparison, laser ablation of pure Au and pure Ge targets was also performed under the same conditions. HRTEM shows that Ge forms spherical nanoparticles with a characteristic size of {approx}30 nm. Au forms spherical nanoparticles with diameters of {approx}10 nm. Similar to AuGe, it also forms chainlike structures with substantially lower aspect ratio.

  3. Ir-induced activation of Au towards CO adsorption: Ir films deposited on Au{111}

    NASA Astrophysics Data System (ADS)

    Zhang, Tianfu; Driver, Stephen M.; Pratt, Stephanie J.; Jenkins, Stephen J.; King, David A.

    2016-06-01

    We have investigated the interaction of CO with Ir/Au{111} bimetallic surfaces, and the influence of morphology changes as Ir moves sub-surface into the Au bulk, using reflection-absorption infrared spectroscopy (RAIRS). The presence of Ir stabilises CO on exposed regions of the Au surface at temperatures up to around 200 K: we attribute this to low-coordinated Au sites, probably associated with lifting of the clean-surface 'herringbone' reconstruction by Ir deposition. The highest density of active Au sites is obtained after annealing the bimetallic surface to 500-600 K: we attribute this to morphology changes associated with the movement of Ir into bulk Au.

  4. Charged hadron transverse momentum distributions in Au+Au collisions at S=200 GeV

    NASA Astrophysics Data System (ADS)

    Roland, Christof; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt(s_NN) = 200 GeV. The evolution of the spectra for transverse momenta p_T from 0.25 to 5GeV/c is studied as a function of collision centrality over a range from 65 to 344 participating nucleons. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. Comparing peripheral to central Au+Au collisions, we find that the yields at the highest p_T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  5. RHIC Au beam in Run 2014

    SciTech Connect

    Zhang, S. Y.

    2014-09-15

    Au beam at the RHIC ramp in run 2014 is reviewed together with the run 2011 and run 2012. Observed bunch length and longitudinal emittance are compared with the IBS simulations. The IBS growth rate of the longitudinal emittance in run 2014 is similar to run 2011, and both are larger than run 2012. This is explained by the large transverse emittance at high intensity observed in run 2012, but not in run 2014. The big improvement of the AGS ramping in run 2014 might be related to this change. The importance of the injector intensity improvement in run 2014 is emphasized, which gives rise to the initial luminosity improvement of 50% in run 2014, compared with the previous Au-Au run 2011. In addition, a modified IBS model, which is calibrated using the RHIC Au runs from 9.8 GeV/n to 100 GeV/n, is presented and used in the study.

  6. Counterion-Mediated Assembly of Spherical Nucleic Acid-Au Nanoparticle Conjugates (SNA-AuNPs)

    NASA Astrophysics Data System (ADS)

    Kewalramani, Sumit; Moreau, Liane; Guerrero-García, Guillermo; Mirkin, Chad; Olvera de La Cruz, Monica; Bedzyk, Michael; Afosr Muri Team

    2015-03-01

    Controlled crystallization of colloids from solution has been a goal of material scientists for decades. Recently, nucleic acid functionalized spherical Au nanoparticles (SNA-AuNPs) have been programmed to assemble in a wide variety of crystal structures. In this approach, the assembly is driven by Watson-Crick hybridization between DNAs coating the AuNPs. Here, we show that counterions can induce ordered assembly of SNA-AuNPs in bulk solutions, even in the absence of base pairing interactions. The electrostatics-driven assembly of spherical nucleic acid-Au nanoparticle conjugates (SNA-AuNPs) is probed as a function of counterion concentration and counterion valency [ +1 (Na+) or +2 (Ca2+) ] by in situ solution X-ray scattering. Assemblies of AuNPs capped with single-stranded (ss-) or double-stranded (ds-) DNA are examined. SAXS reveals disordered (gas-like) --> face-centered-cubic (FCC) --> glass-like phase transitions with increasing solution ionic strength. These studies demonstrate how non-base-pairing interactions can be tuned to create crystalline assemblies of SNA-AuNPs. The dependence of the inter-SNA-AuNP interactions on counterion valency and stiffness of the DNA corona will be discussed.

  7. Sclerometric study of galvanic AuNi and AuCo coatings

    NASA Astrophysics Data System (ADS)

    Shugurov, A. R.; Panin, A. V.; Shesterikov, E. V.

    2011-03-01

    Mechanisms of wear in galvanic AuNi and AuCo coatings have been studied using the methods of sclerometry and atomic force microscopy. It is demonstrated that the scratch test at a small load can be used for a comparative analysis of the resistance of metal coatings to abrasive wear. It is established that a developed surface relief related to the formation of grain agglomerates provides for a higher wear resistance of AuCo coatings as compared to that of smooth AuNi films, which is explained by dissipation of the elastic energy of the contact interaction of the sclerometric indenter with the sample surface.

  8. DFT study on cysteine adsorption mechanism on Au(111) and Au(110)

    SciTech Connect

    Buimaga-Iarinca, Luiza; Floare, Calin G.; Calborean, Adrian; Turcu, Ioan

    2013-11-13

    Periodic density functional theory calculations were used to investigate relevant aspects of adsorption mechanisms of cysteine dimers in protonated form on Au(111) and Au(110) surfaces. The projected densities of states are explicitly discussed for all main chemical groups of cysteine, i.e. the amino group (NH2), the thiol group (SH) and the carboxylic group (COOH) to identify differences in adsorption mechanism. Special emphasis is put on the analysis of changes in the electronic structure of molecules adsorbed on Au(111) and Au(110) surfaces as well as the accompanying charge transfer mechanisms at molecule-substrate interaction.

  9. Systematic Measurements of Identified Particle Spectra in pp, d+Au and Au+Au Collisions from STAR

    SciTech Connect

    STAR Coll

    2009-04-11

    Identified charged particle spectra of {pi}{sup {+-}}, K{sup {+-}}, p and {bar p} at mid-rapidity (|y| < 0.1) measured by the dE/dx method in the STAR-TPC are reported for pp and d + Au collisions at {radical}s{sub NN} = 200 GeV and for Au + Au collisions at 62.4 GeV, 130 GeV, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm{sub 3} for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au + Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au + Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters due to the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close to the predicted phase

  10. Systematic measurements of identified particle spectra in pp, d+Au, and Au+Au collisions at the star detector.

    SciTech Connect

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Krueger, K.; Spinka, H. M.; Underwood, D. G.; High Energy Physics; Univ. of Illinois; Panjab Univ.; Variable Energy Cyclotron Centre; Kent State Univ.; Particle Physic Lab.; STAR Collaboration

    2009-01-01

    Identified charged-particle spectra of {pi}{sup {+-}}, K{sup {+-}}, p, and {bar p} at midrapidity (|y|<0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d+Au collisions at {radical}s{sub NN} = 200 GeV and for Au+Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm{sup 3} for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au+Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au+Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of

  11. Systematic measurements of identified particle spectra in pp, d+Au, and Au+Au collisions at the STAR detector

    NASA Astrophysics Data System (ADS)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bruna, E.; Bueltmann, S.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Chung, S. U.; Clarke, R. F.; Codrington, M. J. M.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Silva, C. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; de Souza, R. Derradi; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Edwards, W. R.; Efimov, L. G.; Elhalhuli, E.; Elnimr, M.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gaillard, L.; Gangadharan, D. R.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jin, F.; Jones, P. G.; Joseph, J.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; Lapointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Levine, M. J.; Li, C.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Matis, H. S.; Matulenko, Yu. A.; McShane, T. S.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mitchell, J.; Mohanty, B.; Molnar, L.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, C.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Reed, R.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Rykov, V.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X.-H.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T. J. M.; de Toledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tlusty, D.; Tokarev, M.; Tram, V. N.; Trattner, A. L.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; van Leeuwen, M.; Molen, A. M. Vander; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasilevski, I. M.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, Q.; Wang, X.; Wang, X. L.; Wang, Y.; Webb, J. C.; Westfall, G. D.; Whitten, C., Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, H.; Zhang, S.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zuo, J. X.

    2009-03-01

    Identified charged-particle spectra of π±, K±, p, and pmacr at midrapidity (|y|<0.1) measured by the dE/dx method in the STAR (solenoidal tracker at the BNL Relativistic Heavy Ion Collider) time projection chamber are reported for pp and d+Au collisions at sNN=200 GeV and for Au+Au collisions at 62.4, 130, and 200 GeV. Average transverse momenta, total particle production, particle yield ratios, strangeness, and baryon production rates are investigated as a function of the collision system and centrality. The transverse momentum spectra are found to be flatter for heavy particles than for light particles in all collision systems; the effect is more prominent for more central collisions. The extracted average transverse momentum of each particle species follows a trend determined by the total charged-particle multiplicity density. The Bjorken energy density estimate is at least several GeV/fm3 for a formation time less than 1 fm/c. A significantly larger net-baryon density and a stronger increase of the net-baryon density with centrality are found in Au+Au collisions at 62.4 GeV than at the two higher energies. Antibaryon production relative to total particle multiplicity is found to be constant over centrality, but increases with the collision energy. Strangeness production relative to total particle multiplicity is similar at the three measured RHIC energies. Relative strangeness production increases quickly with centrality in peripheral Au+Au collisions, to a value about 50% above the pp value, and remains rather constant in more central collisions. Bulk freeze-out properties are extracted from thermal equilibrium model and hydrodynamics-motivated blast-wave model fits to the data. Resonance decays are found to have little effect on the extracted kinetic freeze-out parameters because of the transverse momentum range of our measurements. The extracted chemical freeze-out temperature is constant, independent of collision system or centrality; its value is close

  12. Aspects épidémiologiques des fractures de membres liées à l'exercice de la fonction militaire au Togo

    PubMed Central

    Akpoto, Yao Messanvi; Abalo, Anani; Gnandi-pio, Faré; Sonhaye, Lantam; Tchaou, Mazamaesso; Sama, Hamza Doles; Assenouwe, Sarakawabalo; Lamboni, Damessane; Amavi, Kossigan Adodossi; Adam, Saliou; Kpelao, Essossinam; Tengue, Kodjo; Songne-Gnamkoulamba, Badjona

    2015-01-01

    Le but de notre étude était de déterminer la fréquence des fractures de membres liées à l'exercice de la fonction militaire au sein des Forces de Défense et de Sécurité en milieu africain en vue de ressortir l'impact des différentes circonstances de survenue. Nous avons entrepris une étude rétrospective descriptive allant du 1er janvier 2004 au 31 décembre 2013. Elle a concerné les agents des forces de défense et de sécurité traités pour des fractures de membres au cours de cette période. Sept cent quatre (704) cas de fractures de membres ont été dénombrés. L’âge moyen des patients était de 30,57 ans avec des extrêmes de 19 et 55 ans. La prédominance masculine était nette (95,71%). L'Armée de Terre (51,05%) et la Gendarmerie Nationale (38,86%) étaient les plus représentées. Les hommes du rang étaient majoritaires (43,08%), suivis des sous-officiers (32,59%). La fréquence annuelle des fractures de membres en rapport avec la profession militaire était de 63 cas. Les fractures de jambe étaient les lésions les plus recensées (32,96%). Les Formations et les stages militaires ont été les circonstances de survenue les plus rencontrées (42,60%), suivies des accidents de la circulation (39,43%). La perte des journées de service liée à ces lésions était estimée à 14009 jours par an. Les fractures de jambes occupent le premier rang des fractures de membres en rapport avec l'exercice de la profession militaire. Les formations-stages militaires et les accidents de la voie publique en sont les deux grandes circonstances de survenue. PMID:27081434

  13. 100-MeV proton beam intensity measurement by Au activation analysis using 197Au(p, pn)196Au and 197Au(p, p3n)194Au reactions

    NASA Astrophysics Data System (ADS)

    Mokhtari Oranj, Leila; Jung, Nam-Suk; Oh, Joo-Hee; Lee, Hee-Seock

    2016-05-01

    The proton beam intensity of a 100-MeV proton linac at the Korea Multi-purpose Accelerator Complex (KOMAC) was measured by an Au activation analysis using 197Au(p, pn)196Au and 197Au(p, p3n)194Au reactions to determine the accuracy and precision of beam intensity measurement using Gafchromic film dosimetry method. The target, irradiated by 100-MeV protons, was arranged in a stack consisting of Au, Al foils and Pb plates. The yields of produced radio-nuclei in Au foils were obtained by gamma-ray spectroscopy. The FLUKA code was employed to calculate the energy spectrum of protons onto the front surface of Au foils located at three different depth points of the target and also to investigate the condition of incident beam on the target. A good agreement was found between the beam intensity measurements using the activation analysis method at three different depth points of the target. An excellent agreement was also observed between the beam intensity measurements using the Au activation analysis method and the dosimetry method using Gafchromic film.

  14. Coinfection pulmonaire par pneumocystis jirovecii et pseudomonas aeruginosa au cours du SIDA: à propos de deux cas

    PubMed Central

    Mamoudou, Savadogo; Bellaud, Guillaume; Ana, Canestri; Gilles, Pialoux

    2015-01-01

    Rapporter deux cas cliniques de coinfections pulmonaires par Pneumocystis jirovecii et par Pseudomonas aeruginosa chez des patients vivant avec le VIH. Les deux patients étaient âgés respectivement de 32 ans et 46 ans. Un patient a été pris en charge à l'hôpital Yalgado Ouédraogo de Ouagadougou au Burkina Faso et l'autre a été pris en charge à l'hôpital Ténon de Paris, en France. Les deux souffraient de pneumopathie confirmée à la radiographie et à la tomodensitométrie. L'un des patients était sévèrement immuno déprimé, contrairement à l'autre. L'examen bactériologique dans les crachats avait permis d'isoler Pseudomonas aeruginosa et Pneumocystis jirovecii chez les deux patients. Sous traitement, l’évolution a été favorable. Les coinfections morbides sont relativement fréquentes chez les patients vivant avec le VIH. Devant une symptomatologie respiratoire du sujet vivant avec le VIH, il faut savoir rechercher en plus du Bacille de Koch, Pneumocystis jirovecii et Pseudomonas aeruginosa par un lavage broncho alvéolaire. PMID:26516396

  15. EVENT STRUCTURE AT RHIC FROM P-P TO AU-AU.

    SciTech Connect

    TRAINOR,T.A.

    2004-03-15

    Several correlation analysis techniques are applied to p-p and Au-Au collisions at RHIC. Strong large-momentum-scale correlations are observed which can be related to local charge and momentum conservation during hadronization and to minijet (minimum-bias parton fragment) correlations.

  16. Using supported Au nanoparticles as starting material for preparing uniform Au/Pd bimetallic catalysts

    SciTech Connect

    Villa, Alberto; Prati, Laura; Su, Dangshen; Wang, Di; Veith, Gabriel M

    2010-01-01

    One of the best methods for producing bulk homogeneous (composition) supported bimetallic AuPd clusters involves the immobilization of a protected Au seed followed by the addition of Pd. This paper investigates the importance of this gold seed in controlling the resulting bimetallic AuPd clusters structures, sizes and catalytic activities by investigating three different gold seeds. Uniform Au-Pd alloy were obtained when a steric/electrostatic protecting group, poly(vinyl alcohol) (PVA), was used to form the gold clusters on activated carbon (AC). In contrast Au/AC precursors prepared using Au nanoparticles with only electrostatic stabilization (tetrakis(hydroxypropyl)phosphonium chloride (THPC)), or no stabilization (magnetron sputtering) produced inhomogeneous alloys and segregation of the gold and palladium. The uniform alloyed catalyst (Pd{at}Au{sub PVA}/AC) is the most active and selective catalyst, while the inhomogenous catalysts are less active and selective. Further study of the PVA protected Au clusters revealed that the amount of PVA used is also critical for the preparation of uniform alloyed catalyst, their stability, and their catalytic activity.

  17. Electrochemical Characterization of Protein Adsorption onto YNGRT-Au and VLGXE-Au Surfaces.

    PubMed

    Trzeciakiewicz, Hanna; Esteves-Villanueva, Jose; Soudy, Rania; Kaur, Kamaljit; Martic-Milne, Sanela

    2015-01-01

    The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6](3-/4-). The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in Rct for all three proteins. Furthermore, an increase in Rct was observed with CD13 (an aminopeptidase overexpressed in certain cancers) in comparison to the other proteins when the VLGXE-Au surface was modified with n-butylamine as a blocking agent. The electrochemical data indicated that protein adsorption may be modulated by tailoring the peptide sequence on Au surfaces and that blocking agents and diluents play a key role in promoting or preventing protein adsorption. The peptide-Au platform may also be used for targeting cancer biomarkers with designer peptides. PMID:26262621

  18. The extraction characteristic of Au-Ag from Au concentrate by thiourea solution

    NASA Astrophysics Data System (ADS)

    Kim, Bongju; Cho, Kanghee; On, Hyunsung; Choi, Nagchoul; Park, Cheonyoung

    2013-04-01

    The cyanidation process has been used commercially for the past 100 years, there are ores that are not amenable to treatment by cyanide. Interest in alternative lixiviants, such as thiourea, halogens, thiosulfate and malononitrile, has been revived as a result of a major increase in gold price, which has stimulated new developments in extraction technology, combined with environmental concern. The Au extraction process using the thiourea solvent has many advantages over the cyanidation process, including higher leaching rates, faster extraction time and less than toxicity. The purpose of this study was investigated to the extraction characteristic of Au-Ag from two different Au concentrate (sulfuric acid washing and roasting) under various experiment conditions (thiourea concentration, pH of solvent, temperature) by thiourea solvent. The result of extraction experiment showed that the Au-Ag extraction was a fast extraction process, reaching equilibrium (maximum extraction rate) within 30 min. The Au-Ag extraction rate was higher in the roasted concentrate than in the sulfuric acid washing. The higher the Au-Ag extraction rate (Au - 70.87%, Ag - 98.12%) from roasted concentrate was found when the more concentration of thiourea increased, pH decreased and extraction temperature increased. This study informs extraction method basic knowledge when thiourea was a possibility to eco-/economic resources of Au-Ag utilization studies including the hydrometallurgy.

  19. Electrochemical Characterization of Protein Adsorption onto YNGRT-Au and VLGXE-Au Surfaces

    PubMed Central

    Trzeciakiewicz, Hanna; Esteves-Villanueva, Jose; Soudy, Rania; Kaur, Kamaljit; Martic-Milne, Sanela

    2015-01-01

    The adsorption of the proteins CD13, mucin and bovine serum albumin on VLGXE-Au and YNGRT-Au interfaces was monitored by electrochemical impedance spectroscopy in the presence of [Fe(CN)6]3−/4−. The hydrophobicity of the Au surface was tailored using specific peptides, blocking agents and diluents. The combination of blocking agents (ethanolamine or n-butylamine) and diluents (hexanethiol or 2-mercaptoethanol) was used to prepare various peptide-modified Au surfaces. Protein adsorption onto the peptide-Au surfaces modified with the combination of n-butylamine and hexanethiol produced a dramatic decrease in the charge transfer resistance, Rct, for all three proteins. In contrast, polar peptide-surfaces induced a minimal change in Rct for all three proteins. Furthermore, an increase in Rct was observed with CD13 (an aminopeptidase overexpressed in certain cancers) in comparison to the other proteins when the VLGXE-Au surface was modified with n-butylamine as a blocking agent. The electrochemical data indicated that protein adsorption may be modulated by tailoring the peptide sequence on Au surfaces and that blocking agents and diluents play a key role in promoting or preventing protein adsorption. The peptide-Au platform may also be used for targeting cancer biomarkers with designer peptides. PMID:26262621

  20. Identified particles in Au+Au collisions at S=200 GeV

    NASA Astrophysics Data System (ADS)

    Phobos Collaboration; Wosiek, Barbara; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    The yields of identified particles have been measured at RHIC for Au+Au collisions at S=200 GeV using the PHOBOS spectrometer. The ratios of antiparticle to particle yields near mid-rapidity are presented. The first measurements of the invariant yields of charged pions, kaons and protons at very low transverse momenta are also shown.

  1. Observation of anisotropic event shapes and transverse flow in ultrarelativistic Au+Au collisions

    SciTech Connect

    Barrette, J.; Bellwied, R.; Bennett, S.; Braun-Munzinger, P.; Cleland, W.E.; Clemen, M.; Cole, J.; Cormier, T.M.; David, G.; Dee, J.; Dietzsch, O.; Drigert, M.; Gilbert, S.; Hall, J.R.; Hemmick, T.K.; Herrmann, N.; Hong, B.; Jiang, C.L.; Kwon, Y.; Lacasse, R.; Lukaszew, A.; Li, Q.; Ludlam, T.W.; McCorkle, S.; Mark, S.K.; Matheus, R.; O'Brien, E.; Panitkin, S.; Piazza, T.; Pruneau, C.; Rao, M.N.; Rosati, M.; daSilva, N.C.; Sedykh, S.; Sonnadara, U.; Stachel, J.; Takai, H.; Takagui, E.M.; Voloshin, S.; Wang, G.; Wessels, J.P.; Woody, C.L.; Xu, N.; Zhang, Y.; Zhang, Z.; Zou, C. Gesellschaft fuer Schwerionenforschung, Darmstadt Idaho National Engineering Laboratory, Idaho Falls, Idaho 83402 McGill Univesity, Montreal, H3A 2T8 University of Pittsburgh, Pittsburgh, Pennsylvania 15260 SUNY, Stony Brook, New York, 11794 University of Sao Paulo, Sao Paulo

    1994-11-07

    Event shapes for Au + Au collisions at 11.4 GeV/[ital c] per nucleon were studied over nearly the full solid angle with the E877 apparatus. The analysis was performed by Fourier expansion of azimuthal distributions of the transverse energy ([ital E][sub [ital T

  2. Surpoids et obésité dans la population au-dessus de 20 ans en milieu urbain bamakois (Mali)

    PubMed Central

    Oumar Bâ, Hamidou; Menta, Ichaka; Camara, Youssouf; Sangaré, Ibrahima; Sidibé, Noumou; Doumbia, Seydou; Diarra, Mamadou Bocary

    2014-01-01

    Introduction Il est question dans notre travail d’étudier le SP et l'OB et les facteurs associés dans la population âgée de 20 ans ou plus. Méthodes Notre échantillon a été obtenu à partir d'une enquête sur les pathologies cardiovasculaires dans le District de Bamako et impliquant 2199 sujets de 5-104 ans, en sélectionnant tous les sujets âgés d'au moins 20 ans (1162). Pour chaque sujet, l'IMC, rapport taille / hanche et le tour de taille ont été déterminées. Les données ont été analysées avec SPSS 12. Résultats L’âge moyen était de 36,86 années, 61,4% étaient des femmes, 49,7% dans le secteur informel et 38,0% avaient réalisé l'enseignement primaire. Facteurs de risque cardiovasculaires étaient l'inactivité physique (72,4%), le tabagisme (12,2%) et hypertension (26,7%). La prévalence de l'obésité était de 8,8 et 14,7% respectivement sur la base de l'indice de masse et le tour de taille. Conclusion Le SP et l'OB sont à prendre en compte dans les mesures de politique sanitaire que dans la pratique quotidienne des professionnels de santé, il est peut-être plus utile d'utiliser plusieurs paramètres pour être à même de bien stratifier nos patients par rapport à leur risque. PMID:25932065

  3. The role of plasmons and interband transitions in the color of AuAl2, AuIn2, and AuGa2

    NASA Astrophysics Data System (ADS)

    Keast, V. J.; Birt, K.; Koch, C. T.; Supansomboon, S.; Cortie, M. B.

    2011-09-01

    First principles calculations of the optical properties of the intermetallic compounds AuAl2, AuIn2, and AuGa2 have been performed. Analysis of the dielectric functions showed that AuAl2 is unique because a bulk plasmon is seen in the optical region and contributes to the purple color of this material. An experimental electron energy-loss spectrum showed excellent agreement with the theoretical prediction and confirmed the presence of the bulk plasmon.

  4. Jets and dijets in Au+Au and p+p collisions at RHIC

    SciTech Connect

    Hardtke, D.; STAR Collaboration

    2002-12-09

    Recent data from RHIC suggest novel nuclear effects in the production of high p{sub T} hadrons. We present results from the STAR detector on high p{sub T} angular correlations in Au+Au and p+p collisions at {radical}S = 200 GeV/c. These two-particle angular correlation measurements verify the presence of a partonic hard scattering and fragmentation component at high p{sub T} in both central and peripheral Au+Au collisions. When triggering on a leading hadron with p{sub T}>4 GeV, we observe a quantitative agreement between the jet cone properties in p+p and all centralities of Au+Au collisions. This quantitative agreement indicates that nearly all hadrons with p{sub T}>4 GeV/c come from jet fragmentation and that jet fragmentation properties are not substantially modified in Au+Au collisions. STAR has also measured the strength of back-to-back high p{sub T} charged hadron correlations, and observes a small suppression of the back-to-back correlation strength in peripheral collisions, and a nearly complete disappearance o f back-to-back correlations in central Au+Au events. These phenomena, together with the observed strong suppression of inclusive yields and large value of elliptic flow at high p{sub T}, are consistent with a model where high p{sub T} hadrons come from partons created near the surface of the collision region, and where partons that originate or propagate towards the center of the collision region are substantially slowed or completely absorbed.

  5. Interaction of HNCO with Au(111) surfaces

    NASA Astrophysics Data System (ADS)

    Farkas, A. P.; Berkó, A.; Solymosi, F.

    2012-08-01

    The surface chemistry of isocyanic acid, HNCO, and its dissociation product, NCO, was studied on clean, O-dosed and Ar ion bombarded Au(111) surfaces. The techniques used are high resolution energy loss spectroscopy (HREELS) and temperature-programmed desorption (TPD). The structure of Ar ion etched surface is explored by scanning tunneling microscopy (STM). HNCO adsorbs molecularly on Au(111) surface at 100 K yielding strong losses at 1390, 2270 and 3230 cm- 1. The weakly adsorbed HNCO desorbs in two peaks characterized by Tp = 130 and 145 K. The dissociation of the chemisorbed HNCO occurs at 150 K to give NCO species characterized by a vibration at 2185 cm- 1. The dissociation process is facilitated by the presence of preadsorbed O and by defect sites on Au(111) produced by Ar ion bombardment. In the latter case the loss feature of NCO appeared at 2130 cm- 1. Isocyanate on Au(111) surface was found to be more stable than on the single crystal surfaces of Pt-group metals. Results are compared with those obtained on supported Au catalysts.

  6. Synthesis and characterization in AuCu–Si nanostructures

    SciTech Connect

    Novelo, T.E.; Amézaga-Madrid, P.; Maldonado, R.D.; Oliva, A.I.; Alonzo-Medina, G.M.

    2015-03-15

    Au/Cu bilayers with different Au:Cu concentrations (25:75, 50:50 and 75:25 at.%) were deposited on Si(100) substrates by thermal evaporation. The thicknesses of all Au/Cu bilayers were 150 nm. The alloys were prepared by thermal diffusion into a vacuum oven with argon atmosphere at 690 K during 1 h. X-ray diffraction analysis revealed different phases of AuCu and CuSi alloys in the samples after annealing process. CuSi alloys were mainly obtained for 25:75 at.% samples, meanwhile the AuCuII phase dominates for samples prepared with 50:50 at.%. Additionally, the Au:Cu alloys with 75:25 at.%, produce Au{sub 2}Cu{sub 3} and Au{sub 3}Cu phases. The formed alloys were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) to study the morphology and the elemental concentration of the formed alloys. - Highlights: • AuCu/Si alloy thin films were prepared by thermal diffusion. • Alloys prepared with 50 at.% of Au produce the AuCuII phase. • Alloys prepared with 75 at.% of Au produce Au{sub 3}Cu and Au{sub 2}Cu{sub 3} phases. • All alloys present diffusion of Si and Cu through the CuSi alloy formation.

  7. Au nanoparticles films used in biological sensing

    NASA Astrophysics Data System (ADS)

    Rosales Pérez, M.; Delgado Macuil, R.; Rojas López, M.; Gayou, V. L.; Sánchez Ramírez, J. F.

    2009-05-01

    Lactobacillus para paracasei are used commonly as functional food and probiotic substances. In this work Au nanoparticles self-assembled films were used for Lactobacillus para paracasei determination at five different concentrations. Functionalized substrates were immersed in a colloidal solution for one and a half hour at room temperature and dried at room temperature during four hours. After that, drops of Lactobacillus para paracasei in aqueous solution were put into the Au nanoparticles film and let dry at room temperature for another two hours. Infrared spectroscopy in attenuated total reflectance sampling mode was used to observe generation peaks due to substrate silanization, enhancement of Si-O band intensity due to the Au colloids added to silanized substrate and also to observe the enhancement of Lactobacillus para paracasei infrared intensity of the characteristic frequencies at 1650, 1534 and 1450 cm-1 due to surface enhancement infrared absorption.

  8. Au-Ag@Au Hollow Nanostructure with Enhanced Chemical Stability and Improved Photothermal Transduction Efficiency for Cancer Treatment.

    PubMed

    Jiang, Tongtong; Song, Jiangluqi; Zhang, Wenting; Wang, Hao; Li, Xiaodong; Xia, Ruixiang; Zhu, Lixin; Xu, Xiaoliang

    2015-10-01

    Despite the fact that Au-Ag hollow nanoparticles (HNPs) have gained much attention as ablation agents for photothermal therapy, the instability of the Ag element limits their applications. Herein, excess Au atoms were deposited on the surface of a Au-Ag HNP by improving the reduction power of l-ascorbic acid (AA) and thereby preventing the reaction between HAuCl4 and the Ag element in the Au-Ag alloy nanostructure. Significantly, the obtained Au-Ag@Au HNPs show excellent chemical stability in an oxidative environment, together with remarkable increase in extinction peak intensity and obvious narrowing in peak width. Moreover, finite-difference time-domain (FDTD) was used to simulate the optical properties and electric field distribution of HNPs. The calculated results show that the proportion of absorption cross section in total extinction cross section increases with the improvement of Au content in HNP. As predicted by the theoretical calculation results, Au-Ag@Au nanocages (NCs) exhibit a photothermal transduction efficiency (η) as high as 36.5% at 808 nm, which is higher than that of Au-Ag NCs (31.2%). Irradiated by 808 nm laser at power densities of 1 W/cm(2), MCF-7 breast cancer cells incubated with PEGylated Au-Ag@Au NCs were seriously destroyed. Combined together, Au-Ag@Au HNPs with enhanced chemical stability and improved photothermal transduction efficiency show superior competitiveness as photothermal agents. PMID:26371629

  9. The role of interfaces in the magnetoresistance of Au/Fe/Au/Fe/GaAs(001)

    SciTech Connect

    Enders, A.; Monchesky, T. L.; Myrtle, K.; Urban, R.; Heinrich, B.; Kirschner, J.; Zhang, X.-G.; Butler, W. H.

    2001-06-01

    The electron transport and magnetoresistance (MR) were investigated in high quality crystalline epitaxial Fe(001) and Au(001) films and exchange coupled Au/Fe/Au/Fe/GaAs(001) trilayer structures. Fits to the experimental data were based on the semiclassical Boltzmann equation, which incorporates the electronic properties obtained from first-principles local density functional calculations. The fits require a surprisingly high asymmetry for the spin dependent electron lifetimes in Fe, {tau}{sup {down_arrow}}/{tau}{sup {up_arrow}}=10 at room temperature. Despite the large atomic terraces at the Au/vacuum and Fe/GaAs interfaces the scattering at the outer interfaces was found to be diffuse. The origin of MR in Au/Fe/Au/Fe/GaAs(001) structures is due to electron channeling in the Au spacer layer. The measured MR is consistent with the diffusivity parameters s{sup {up_arrow}}=0.55, s{sup {down_arrow}}=0.77 at the metal{endash}metal interfaces. {copyright} 2001 American Institute of Physics.

  10. Plasmonic Fano resonance and dip of Au-SiO2-Au nanomatryoshka.

    PubMed

    Liaw, Jiunn-Woei; Chen, Huang-Chih; Kuo, Mao-Kuen

    2013-01-01

    This study theoretically investigates Fano resonances and dips of an Au-SiO2-Au nanomatryoshka that is excited by a nearby electric dipole. An analytical solution of dyadic Green's functions is used to analyze the radiative and nonradiative power spectra of a radial dipole in the proximity of a nanomatryoshka. From these spectra, the plasmon modes and Fano resonances that accompany the Fano dips are identified. In addition, the scattering and absorption spectra of a nanomatryoshka that is illuminated by a plane wave are investigated to confirm these modes and Fano dips. Our results reveal that a Fano dip splits each of the dipole and quadrupole modes into bonding and anti-bonding modes. The Fano dip and resonance result from the destructive interference of the plasmon modes of the Au shell and the Au core. The Fano factors that are obtained from the nonradiative power spectra of the Au shell and the Au core of a nanomatryoshka are in accordance with those obtained from the absorption cross section spectra. Moreover, these Fano factors increase as the plasmonic coupling of the Au shell with the core increases for both dipole and quadrupole modes. PMID:24206789

  11. Plasmonic Fano resonance and dip of Au-SiO2-Au nanomatryoshka

    PubMed Central

    2013-01-01

    This study theoretically investigates Fano resonances and dips of an Au-SiO2-Au nanomatryoshka that is excited by a nearby electric dipole. An analytical solution of dyadic Green's functions is used to analyze the radiative and nonradiative power spectra of a radial dipole in the proximity of a nanomatryoshka. From these spectra, the plasmon modes and Fano resonances that accompany the Fano dips are identified. In addition, the scattering and absorption spectra of a nanomatryoshka that is illuminated by a plane wave are investigated to confirm these modes and Fano dips. Our results reveal that a Fano dip splits each of the dipole and quadrupole modes into bonding and anti-bonding modes. The Fano dip and resonance result from the destructive interference of the plasmon modes of the Au shell and the Au core. The Fano factors that are obtained from the nonradiative power spectra of the Au shell and the Au core of a nanomatryoshka are in accordance with those obtained from the absorption cross section spectra. Moreover, these Fano factors increase as the plasmonic coupling of the Au shell with the core increases for both dipole and quadrupole modes. PMID:24206789

  12. Fabrication of segmented Au/Co/Au nanowires: insights in the quality of Co/Au junctions.

    PubMed

    Jang, Bumjin; Pellicer, Eva; Guerrero, Miguel; Chen, Xiangzhong; Choi, Hongsoo; Nelson, Bradley J; Sort, Jordi; Pané, Salvador

    2014-08-27

    Electrodeposition is a versatile method, which enables the fabrication of a variety of wire-like nanoarchitectures such as nanowires, nanorods, and nanotubes. By means of template-assisted electrodeposition, segmented Au/Co/Au nanowires are grown in anodic aluminum oxide templates from two different electrolytes. To tailor the properties of the cobalt segments, several electrochemical conditions are studied as a function of current density, pulse deposition, and pH. The morphology, crystal structure, and magnetic properties are accordingly investigated. Changes in the deposition conditions affect the cobalt electrocrystallization process directly. Cobalt tends to crystallize mainly in the hexagonal close-packed structure, which is the reason cobalt might not accommodate satisfactorily on the face-centered cubic Au surface or vice versa. We demonstrate that by modifying the electrolyte and the applied current densities, changes in the texture and the crystalline structure of cobalt lead to a good quality connection between dissimilar segments. In particular, lowering the bath pH, or using pulse plating at a high overpotential, produces polycrystalline fcc Co and thus well-connected Co/Au bimetallic junctions with smooth interface. These are crucial factors to be carefully considered taking into account that nanowires are potential building blocks in micro- and nanoelectromechanical systems. PMID:25025496

  13. Evidence of final-state suppression of high-p{_ T} hadrons in Au + Au collisions using d + Au measurements at RHIC

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.; Zhang, J.

    Transverse momentum spectra of charged hadrons with pT < 6 GeV/c have been measured near mid-rapidity (0.2 < ɛ < 1.4) by the PHOBOS experiment at RHIC in Au + Au and d + Au collisions at {√ {s{NN}} = {200 GeV}}. The spectra for different collision centralities are compared to {p + ¯ {p}} collisions at the same energy. The resulting nuclear modification factor for central Au + Au collisions shows evidence of strong suppression of charged hadrons in the high-pT region (>2 GeV/c). In contrast, the d + Au nuclear modification factor exhibits no suppression of the high-pT yields. These measurements suggest a large energy loss of the high-pT particles in the highly interacting medium created in the central Au + Au collisions. The lack of suppression in d + Au collisions suggests that it is unlikely that initial state effects can explain the suppression in the central Au + Au collisions. PACS: 25.75.-q

  14. Revisiting the S-Au(111) interaction: Static or Dynamic?

    SciTech Connect

    Biener, M M; Biener, J; Friend, C M

    2004-08-17

    The chemical inertness typically observed for Au does not imply a general inability to form stable bonds with non-metals but is rather a consequence of high reaction barriers. The Au-S interaction is probably the most intensively studied interaction of Au surfaces with non-metals as, for example, it plays an important role in Au ore formation, and controls the structure and dynamics of thiol-based self-assembled-monolayers (SAMs). In recent years a quite complex picture of the interaction of sulfur with Au(111) surfaces emerged, and a variety of S-induced surface structures was reported under different conditions. The majority of these structures were interpreted in terms of a static Au surface, where the positions of the Au atoms remain essentially unperturbed. Here we demonstrate that the Au(111) surface exhibits a very dynamic character upon interaction with adsorbed sulfur: low sulfur coverages modify the surface stress of the Au surface leading to lateral expansion of the surface layer; large-scale surface restructuring and incorporation of Au atoms into a growing two-dimensional AuS phase were observed with increasing sulfur coverage. These results provide new insight into the Au-S surface chemistry, and reveal the dynamic character of the Au(111) surface.

  15. Thrombose de la veine porte au cours d'une hépatite auto immune type 1

    PubMed Central

    Salem, Bouomrani; Afef, Farah; Nadia, Bouassida; Nabil, Ayadi; Maher, Béji

    2013-01-01

    Notre but est de rapporter une observation particulière de thrombose de la veine porte survenant au décours d'une hépatite auto-immune type 1 non compliquée qui, à notre connaissance, n'a pas été rapportée auparavant. Il s'agit d'une patiente de 35 ans connue ayant une dermatose bulleuse auto immune (DBAI) type pemphigus confirmée histologiquement et immunologiquement qui fut explorée pour des coliques hépatiques avec élévations des transaminases et un épisode d'ictère spontanément résolutif. Les explorations ont permis de retenir le diagnostic d'une hépatite auto immune de type 1. Traitée par corticothérapie systémique à la dose de 1 mg/kg/j pour sa DBAI, l'évolution était favorable avec stabilisation simultanée de l'atteinte hépatique durant 19 ans. On découvre sur l'échographie abdominale de contrôle une thrombose partielle du tronc porte confirmée par le scanner X abdominal. Le bilan étiologique de cette thrombose est resté négatif. De même il n'y avait pas de signes cliniques, biologiques, endoscopiques ou radiologiques de cirrhose ni de dégénérescence maligne. Elle était efficacement antigoagulée par les antagonistes de la vitamine K. Dans notre observation le bilan étiologique; aussi exhaustif que possible, de cette thrombose est resté négatif, éliminant en particulier une cirrhose, une dégénérescence maligne et un syndrome des anti phospholipides associé et permettant de la rattacher directement à l'hépatopathie chronique auto immune. PMID:23734275

  16. Controlled deposition of Au on (BiO)2CO3 microspheres: the size and content of Au nanoparticles matter.

    PubMed

    Li, Qiuyan; Hao, Xiaodong; Guo, Xiaolong; Dong, Fan; Zhang, Yuxin

    2015-05-21

    Novel 3D Au/(BiO)2CO3 (Au/BOC) heterostructures with size-controlled Au nanoparticles (NPs) (2-10 nm) were first synthesized and used in photocatalytic removal of ppb-level NO for air cleaning. The photocatalytic performance of Au/BOC heterostructures was enhanced by fine-tuning the content of Au and the size of Au NPs. A new photocatalysis mechanism of surface scattering and reflecting (SSR) coupled with surface plasmon resonance (SPR) was proposed to understand the enhanced photocatalytic activity. PMID:25906416

  17. Charged hadron transverse momentum distributions in Au+Au collisions at √ SNN = 200 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; van Nieuwenhuizen, Gerrit; PHOBOS Collaboration

    2003-04-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at √ SNN = 200 GeV. The evolution of the spectra for transverse momenta p T from 0.25 to 5 GeV/C is studied as a function of collision centrality. We find a significant change of the spectral shape between proton-antiproton and peripheral Au+Au collisions. When comparing peripheral to central Au+Au collisions, we find that the yields at the highest p T exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  18. La tuberculose cutanée: observation de six cas confirmés au CHU Souro SANOU (CHUSS) de Bobo-Dioulasso (Burkina Faso)

    PubMed Central

    Andonaba, Jean Baptiste; Barro-Traoré, Fatou; Yaméogo, Téné; Diallo, Boukary; Korsaga-Somé, Nina; Traoré, Adama

    2013-01-01

    La localisation cutanée de la maladie tuberculeuse demeure une forme rare et représente seulement 2,1% des localisations. L'objet de cette étude est de rapporter le profil épidémiologique, anatomoclinique et évolutif des cas de tuberculose ganglio-cutanée diagnostiqués dans un CHU au Burkina Faso. La fréquence de la tuberculose cutanée est très faible au CHUSS. Six cas ont été diagnostiqués entre 2004 et 2010, soit une fréquence de un cas par an. La durée d’évolution des cas allait de deux jusqu’à dix ans avant leur diagnostic. Les lésions observées étaient: trois scrofulodermes, trois gommes, une tuberculose testiculaire associée à un mal de Pott, un cas de polyadénopathies et des cicatrices atropho-rétractiles dans la plupart des cas. Sur le plan anatomopathologique, des granulomes tuberculoïdes ont été mis en évidence dans tous les cas avec une forte réaction tuberculinique à l'IDR. Sous antituberculeux pendant six mois, l’évolution a été bonne dans tous les cas mais au prix de séquelles cutanées cicatricielles inesthétiques. Son ampleur reste peut-être encore méconnue. Le renforcement du plateau technique du CHU et une bonne collaboration interdisciplinaire contribuerait à un meilleur diagnostic et prise en charge de cette affection. PMID:24648863

  19. Suppression of Upsilon production in d + Au and Au + Au collisions at root s(NN) = 200 GeV (vol 735, pg 127, 2014)

    SciTech Connect

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Gliske, S.; Krueger, K.; Spinka, H. M.; Underwood, D. G.

    2014-07-30

    We report measurements of Υ meson production in p + p, d +Au, and Au+Aucollisions using the STAR detector at RHIC. We compare the Υ yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d +Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p +p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Υ (1S + 2S + 3S) in the rapidity range |y| < 1 in d + Aucollisions of RdAu = 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R AA = 0.49 ±0.1(stat.) ±0.02(syst.) ±0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Υ mesons in Au + Aucollisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.

  20. Nanoporous Au: an unsupported pure gold catalyst?

    SciTech Connect

    Wittstock, A; Neumann, B; Schaefer, A; Dumbuya, K; Kuebel, C; Biener, M; Zielasek, V; Steinrueck, H; Gottfried, M; Biener, J; Hamza, A; B?umer, M

    2008-09-04

    The unique properties of gold especially in low temperature CO oxidation have been ascribed to a combination of various effects. In particular, particle sizes below a few nm and specific particle-support interactions have been shown to play important roles. On the contrary, recent reports revealed that monolithic nanoporous gold (npAu) prepared by leaching a less noble metal, such as Ag, out of the corresponding alloy can also exhibit remarkably high catalytic activity for CO oxidation, even though no support is present. Therefore, it was claimed to be a pure and unsupported gold catalyst. We investigated npAu with respect to its morphology, surface composition and catalytic properties. In particular, we studied the reaction kinetics for low temperature CO oxidation in detail taking mass transport limitation due to the porous structure of the material into account. Our results reveal that Ag, even if removed almost completely from the bulk, segregates to the surface resulting in surface concentrations of up to 10 at%. Our data suggest that this Ag plays a significant role in activation of molecular oxygen. Therefore, npAu should be considered as a bimetallic catalyst rather than a pure Au catalyst.

  1. Characterization of Au and Bimetallic PtAu Nanoparticles on PDDA-Graphene Sheets as Electrocatalysts for Formic Acid Oxidation

    NASA Astrophysics Data System (ADS)

    Yung, Tung-Yuan; Liu, Ting-Yu; Huang, Li-Ying; Wang, Kuan-Syun; Tzou, Huei-Ming; Chen, Po-Tuan; Chao, Chi-Yang; Liu, Ling-Kang

    2015-09-01

    Nanocomposite materials of the Au nanoparticles (Au/PDDA-G) and the bimetallic PtAu nanoparticles on poly-(diallyldimethylammonium chloride) (PDDA)-modified graphene sheets (PtAu/PDDA-G) were prepared with hydrothermal method at 90 °C for 24 h. The composite materials Au/PDDA-G and PtAu/PDDA-G were evaluated by transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA) for exploring the structural characterization for the electrochemical catalysis. According to TEM results, the diameter of Au and bimetallic PtAu nanoparticles is about 20-50 and 5-10 nm, respectively. X-ray diffraction (XRD) results indicate that both of PtAu and Au nanoparticles exhibit the crystalline plane of (111), (200), (210), and (311). Furthermore, XRD data also show the 2°-3° difference between pristine graphene sheets and the PDDA-modified graphene sheets. For the catalytic activity tests of Au/PDDA-G and PtAu/PDDA-G, the mixture of 0.5 M aqueous H2SO4 and 0.5 M aqueous formic acid was used as model to evaluate the electrochemical characterizations. The catalytic activities of the novel bimetallic PtAu/graphene electrocatalyst would be anticipated to be superior to the previous electrocatalyst of the cubic Pt/graphene.

  2. Strangelet search in Au+Au collisions at sNN=200 GeV

    NASA Astrophysics Data System (ADS)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Belaga, V. V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Benedosso, F.; Betts, R. R.; Bhardwaj, S.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Blyth, S.-L.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Brandin, A. V.; Bravar, A.; Burton, T. P.; Bystersky, M.; Cadman, R. V.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Callner, J.; Catu, O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chung, S. U.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Moura, M. M. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; Didenko, L.; Dietel, T.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, F.; Dunin, V. B.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Eckardt, V.; Edwards, W. R.; Efimov, L. G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Fu, J.; Gagliardi, C. A.; Gaillard, L.; Ganti, M. S.; Garcia-Solis, E.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. G.; Gos, H.; Grebenyuk, O.; Grosnick, D.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, N.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Henry, T. W.; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D.; Hollis, R.; Horner, M. J.; Huang, H. Z.; Hughes, E. W.; Humanic, T. J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jia, F.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kang, K.; Kapitan, J.; Kaplan, M.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kim, B. C.; Kiryluk, J.; Kisiel, A.; Kislov, E. M.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kouchpil, V.; Kowalik, K. L.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Kuhn, C.; Kulikov, A. I.; Kumar, A.; Kurnadi, P.; Kuznetsov, A. A.; Lamont, M. A. C.; Landgraf, J. M.; Lange, S.; Lapointe, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lehocka, S.; Levine, M. J.; Li, C.; Li, Q.; Li, Y.; Lin, G.; Lin, X.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, J. G.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Martin, L.; Matis, H. S.; Matulenko, Yu. A.; McClain, C. J.; McShane, T. S.; Melnick, Yu.; Meschanin, A.; Millane, J.; Miller, M. L.; Minaev, N. G.; Mioduszewski, S.; Mironov, C.; Mischke, A.; Mitchell, J.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Nepali, N. S.; Netrakanti, P. K.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldenburg, M.; Olson, D.; Pachr, M.; Pal, S. K.; Panebratsev, Y.; Pavlinov, A. I.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Planinic, M.; Pluta, J.; Poljak, N.; Porile, N.; Poskanzer, A. M.; Potekhin, M.; Potrebenikova, E.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Putschke, J.; Qattan, I. A.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Relyea, D.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Sazhin, P. S.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shen, W. Q.; Shimanskiy, S. S.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Staszak, D.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Z.; Surrow, B.; Symons, T. J. M.; Toledo, A. Szanto De; Szeliga, B.; Takahashi, J.; Tang, A. H.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Timoshenko, S.; Tokarev, M.; Trainor, T. A.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; Kolk, N. Van Der; Leeuwen, M. Van; Molen, A. M. Vander; Varma, R.; Vasilevski, I. M.; Vasiliev, A. N.; Vernet, R.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, J. S.; Wang, X. L.; Wang, Y.; Watson, J. W.; Webb, J. C.; Westfall, G. D.; Wetzler, A.; , C. Whitten, Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, J.; Wu, Y.; Xu, N.; Xu, Q. H.; Xu, Z.; Yepes, P.; Yoo, I.-K.; Yue, Q.; Yurevich, V. I.; Zhan, W.; Zhang, H.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zubarev, A. N.; Zuo, J. X.

    2007-07-01

    We have searched for strangelets in a triggered sample of 61 million central (top 4%) Au+Au collisions at sNN=200 GeV near beam rapidities at the STAR solenoidal tracker detector at the BNL Relativistic Heavy Ion Collider. We have sensitivity to metastable strangelets with lifetimes of order ⩾0.1 ns, in contrast to limits over ten times longer in BNL Alternating Gradient Synchrotron (AGS) studies and longer still at the CERN Super Proton Synchrotron (SPS). Upper limits of a few 10-6 to 10-7 per central Au+Au collision are set for strangelets with mass ≳30 GeV/c2.

  3. Watchfully checking rapport with the Primary Child Health Care nurses - a theoretical model from the perspective of parents of foreign origin

    PubMed Central

    2010-01-01

    Background Worldwide, multicultural interaction within health care seems to be challenging and problematic. This is also true among Primary Child Health Care nurses (PCHC nurses) in the Swedish Primary Child Health Care services (PCHC services). Therefore, there was a need to investigate the parents' perspective in-depth. Aim The aim of the study was to construct a theoretical model that could promote further understanding of the variety of experiences of parents of foreign origin regarding their interaction with the PCHC nurses at PCHC services. Method The study used Grounded Theory Methodology. Twenty-one parents of foreign origin in contact with PCHC servicies were interviewed. Results In our study parents were watchfully checking rapport, i.e. if they could perceive sympathy and understanding from the PCHC nurses. This was done by checking the nurse's demeanour and signs of judgement. From these interviews we created a theoretical model illustrating the interactive process between parents and PCHC nurses. Conclusion We found it to be of utmost importance for parents to be certain that it was possible to establish rapport with the PCHC nurse. If not, disruptions in the child's attendance at PCHC services could result. PCHC nurses can use the theoretical model resulting from this study as a basis for understanding parents, avoiding a demeanour and judgements that may cause misunderstandings thus promoting high-quality interaction in PCHC services. PMID:20646287

  4. Directed Flow of Charged Kaons in Au+Au Collisions from the BES Program at RHIC

    NASA Astrophysics Data System (ADS)

    Pandit, Yadav; STAR Collaboration

    2015-08-01

    We report the measurement of the directed flow (v1) for charged kaons in Au+Au collisions at =7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV as a function of rapidity and compare these results for pions, protons and antiprotons. These new kaon results may help to constrain the medium properties and collision dynamics including the in-medium kaon potential and baryon number transport in these collisions.

  5. Flow and bose-einstein correlations in Au-Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Phobos Collaboration; Manly, Steven; Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hofman, D.; Hollis, R. S.; Hołyinski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2003-03-01

    Argonne flow and Bose-Einstein correlations have been measured in Au-Au collisions at S=130 and 200 GeV using the PHOBOS detector at RHIC. The systematic dependencies of the flow signal on the transverse momentum, pseudorapidity, and centrality of the collision, as well as the beam energy are shown. In addition, results of a 3-dimensional analysis of two-pion correlations in the 200 GeV data are presented.

  6. Photoinduced drug release from thermosensitive AuNPs-liposome using a AuNPs-switch.

    PubMed

    An, Xueqin; Zhang, Fan; Zhu, Yinyan; Shen, Weiguo

    2010-10-14

    A thermosensitive liposome with embedded AuNPs in a bilayer was prepared using supercritical CO(2). The AuNPs-liposome can absorb a certain wavelength light, convert optical energy into heat, induce phase transition, and release drug. The results show that drug release from the liposome is due to the photothermic effects inducing phase transition of the liposome rather than destruction of the liposome structure. PMID:20820547

  7. Enhanced Second Harmonic Generation in AU/AI2O3/AU absorber

    NASA Astrophysics Data System (ADS)

    Huang, Fenglun; Bai, Songang; Li, Qiang; Qu, Yurui; Min, Qiu

    2016-01-01

    A kind of metal-insulator-metal (MIM) metamaterial absorber for generating second harmonic signal is investigated. The absorbers exhibit high absorption efficiency at the dip and notably enhance the generated second harmonic signal by a factor of over 30, in contrast to an Au/alumina double-layer without Au disk on the top. This study demonstrates the potential of metamaterial absorber for nonlinear photonics.

  8. Fabrication of High Sensitive Immunochromato Kit Using Au Colloid

    NASA Astrophysics Data System (ADS)

    Okamoto, Koji

    Au colloid have characteristics of surface plasmon resonance with absorption at 500 nm~600 nm wavelength. Surface on the citric acid Au colloid can be conjugated with protein eg. antibody. Various particle size of Au colloid makes it high sensitive immunochromato as diagnostics. High sensitive immunochromato will be useful for application of cancer marker eg. prostate specific antigen and influenza early diagnosis.

  9. Bonding, Luminescence, Metallophilicity in Linear Au3 and Au2Ag Chains Stabilized by Rigid Diphosphanyl NHC Ligands.

    PubMed

    Ai, Pengfei; Mauro, Matteo; Gourlaouen, Christophe; Carrara, Serena; De Cola, Luisa; Tobon, Yeny; Giovanella, Umberto; Botta, Chiara; Danopoulos, Andreas A; Braunstein, Pierre

    2016-09-01

    The heterofunctional and rigid ligand N,N'-diphosphanyl-imidazol-2-ylidene (PCNHCP; P = P(t-Bu)2), through its phosphorus and two N-heterocyclic carbene (NHC) donors, stabilizes trinuclear chain complexes, with either Au3 or AgAu2 cores, and dinuclear Au2 complexes. The two oppositely situated PCNHCP (L) ligands that "sandwich" the metal chain can support linear and rigid structures, as found in the known tricationic Au(I) complex [Au3(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 (OTf = CF3SO3; [Au3L2](OTf)3; Chem. Commun. 2014, 50, 103-105) now also obtained by transmetalation from [Ag3(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 ([Ag3L2](OTf)3), or in the mixed-metal tricationic [Au2Ag(μ3-PCNHCP,κP,κCNHC,κP)2](OTf)3 ([Au2AgL2](OTf)3). The latter was obtained stepwise by the addition of AgOTf to the digold(I) complex [Au2(μ2-PCNHCP,κP,κCNHC)2](OTf)2 ([Au2L2](OTf)2). The latter contains two dangling P donors and displays fluxional behavior in solution, and the Au···Au separation of 2.8320(6) Å in the solid state is consistent with metallophilic interactions. In the solvento complex [Au3Cl2(tht)(μ3-PCNHCP,κP,κCNHC,κP)](OTf)·MeCN ([Au3Cl2(tht)L](OTf)·MeCN), which contains only one L and one tht ligand (tht = tetrahydrothiophene), the metal chain is bent (148.94(2)°), and the longer Au···Au separation (2.9710(4) Å) is in line with relaxation of the rigidity due to a more "open" structure. Similar features were observed in [Au3Cl2(SMe2)L](OTf)·2MeCN. A detailed study of the emission properties of [Au3L2](OTf)3, [Au3Cl2(tht)L](OTf)·MeCN, [Au2L2](OTf)2, and [Au2AgL2](OTf)3 was performed by means of steady state and time-resolved photophysical techniques. The complex [Au3L2](OTf)3 displays a bright (photoluminescence quantum yield = 80%) and narrow emission band centered at 446 nm with a relatively small Stokes' shift and long-lived excited-state lifetime on the microsecond timescale, both in solution and in the solid state. In line with the very narrow emission

  10. Experimental and Theoretical Studies on Oxidation of Cu-Au Alloy Surfaces: Effect of Bulk Au Concentration

    PubMed Central

    Okada, Michio; Tsuda, Yasutaka; Oka, Kohei; Kojima, Kazuki; Diño, Wilson Agerico; Yoshigoe, Akitaka; Kasai, Hideaki

    2016-01-01

    We report results of our experimental and theoretical studies on the oxidation of Cu-Au alloy surfaces, viz., Cu3Au(111), CuAu(111), and Au3Cu(111), using hyperthermal O2 molecular beam (HOMB). We observed strong Au segregation to the top layer of the corresponding clean (111) surfaces. This forms a protective layer that hinders further oxidation into the bulk. The higher the concentration of Au in the protective layer formed, the higher the protective efficacy. As a result, of the three Cu-Au surfaces studied, Au3Cu(111) is the most stable against dissociative adsorption of O2, even with HOMB. We also found that this protective property breaks down for oxidations occurring at temperatures above 300 K. PMID:27516137

  11. Identified particle distributions in pp and Au+Au collisions atsqrt sNN=200 GeV

    SciTech Connect

    Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Anderson, M; Arkhipkin, D.; Averichev, G.S.; Badyal,S.K.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele,S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bezverkhny, B.I.; Bhardwaj,S.; Bhaskar, P.; Bhati, A.K.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Botje, M.; Boucham, A.; Brandin, A.; Bravar,A.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez,M.; Carroll, J.; Castillo, J.; Castro, M.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Choi, B.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Dong, X.; Draper, J.E.; Du, F.; Dubey, A.K.; Dunin, V.B.; Dunlop, J.C.; Dutta Majumdar, M.R.; Eckardt, V.; Efimov,L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Filip, P.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Ganti, M.S.; Gutierrez, T.D.; Gagunashvili, N.; Gans, J.; Gaudichet, L.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Grachov, O.; Grigoriev, V.; Cronstal, S.; Grosnick, D.; Guedon, M.; Guertin, S.M.; Gupta, A.; Gushin, E.; Hallman, T.J.; Hardtke, D.; Harris,J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Herston, T.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Huang,S.L.; Humanic, T.J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kaneta, M.; Kaplan, M.; Keane, D.; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Koetke, D.D.; Kollegger, T.; Konstantinov, A.S.; Kopytine,S.M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, P.; Krueger,K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; et al.

    2003-10-06

    Transverse mass and rapidity distributions for charged pions, charged kaons, protons and antiprotons are reported for {radical}sNN = 200 GeV pp and Au+Au collisions at RHIC. The transverse mass distributions are rapidity independent within |y| < 0.5, consistent with a boost-invariant system in this rapidity interval. Spectral shapes and relative particle yields are similar in pp and peripheral Au+Au collisions and change smoothly to central Au+Au collisions. No centrality dependence was observed in the kaon and antiproton production rates relative to the pion production rate from medium-central to central collisions. Chemical and kinetic equilibrium model fits to our data reveal strong radial flow and relatively long duration from chemical to kinetic freeze-out in central Au+Au collisions. The chemical freeze-out temperature appears to be independent of initial conditions at RHIC energies.

  12. Experimental and Theoretical Studies on Oxidation of Cu-Au Alloy Surfaces: Effect of Bulk Au Concentration.

    PubMed

    Okada, Michio; Tsuda, Yasutaka; Oka, Kohei; Kojima, Kazuki; Diño, Wilson Agerico; Yoshigoe, Akitaka; Kasai, Hideaki

    2016-01-01

    We report results of our experimental and theoretical studies on the oxidation of Cu-Au alloy surfaces, viz., Cu3Au(111), CuAu(111), and Au3Cu(111), using hyperthermal O2 molecular beam (HOMB). We observed strong Au segregation to the top layer of the corresponding clean (111) surfaces. This forms a protective layer that hinders further oxidation into the bulk. The higher the concentration of Au in the protective layer formed, the higher the protective efficacy. As a result, of the three Cu-Au surfaces studied, Au3Cu(111) is the most stable against dissociative adsorption of O2, even with HOMB. We also found that this protective property breaks down for oxidations occurring at temperatures above 300 K. PMID:27516137

  13. Charged hadron transverse momentum distributions in Au+Au collisions at √sNN=200 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Ballintijn, M.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Lee, J. W.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2004-01-01

    We present transverse momentum distributions of charged hadrons produced in Au+Au collisions at sNN=200 GeV. The spectra were measured for transverse momenta pT from 0.25 to 4.5 GeV/c in a pseudorapidity range of 0.2<η<1.4. The evolution of the spectra is studied as a function of collision centrality, from 65 to 344 participating nucleons. The results are compared to data from proton-antiproton collisions and Au+Au collisions at lower RHIC energies. We find a significant change of the spectral shape between proton-antiproton and semi-peripheral Au+Au collisions. Comparing semi-peripheral to central Au+Au collisions, we find that the yields at high pT exhibit approximate scaling with the number of participating nucleons, rather than scaling with the number of binary collisions.

  14. The effect of Au amount on size uniformity of self-assembled Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Chen, S.-H.; Wang, D.-C.; Chen, G.-Y.; Chen, K.-Y.

    2008-03-01

    The self-assembled fabrication of nanostructure, a dreaming approach in the area of fabrication engineering, is the ultimate goal of this research. A finding was proved through previous research that the size of the self-assembled gold nanoparticles could be controlled with the mole ratio between AuCl4- and thiol. In this study, the moles of Au were fixed, only the moles of thiol were adjusted. Five different mole ratios of Au/S with their effect on size uniformity were investigated. The mole ratios were 1:1/16, 1:1/8, 1:1, 1:8, 1:16, respectively. The size distributions of the gold nanoparticles were analyzed by Mac-View analysis software. HR-TEM was used to derive images of self-assembled gold nanoparticles. The result reached was also the higher the mole ratio between AuCl4- and thiol the bigger the self-assembled gold nanoparticles. Under the condition of moles of Au fixed, the most homogeneous nanoparticles in size distribution derived with the mole ratio of 1:1/8 between AuCl4- and thiol. The obtained nanoparticles could be used, for example, in uniform surface nanofabrication, leading to the fabrication of ordered array of quantum dots.

  15. Azimuthal anisotropy of ϕ meson in U+U and Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Bairathi, Vipul

    2016-01-01

    The measurements of the azimuthal anisotropy of φ meson in the U+U and Au+Au collisions at the Relativistic Heavy-Ion Collider (RHIC) are reported. The centrality dependence of the Fourier coefficients v2, v3, v4 and v5 is presented for φ meson at midrapidity (|ƞ| < 1.0), in U+U and Au+Au collisions at -√8NN = 193 and 200 GeV, respectively. The ƞ-sub event plane method is used with a n gap of 0.1 to suppress the non-flow effects. A strong centrality dependence is observed for the φ meson elliptic flow (v2), whereas no clear centrality dependence is observed for v3, v4 and v5. Ratios of the Fourier coefficients, v3/v2 and v4/v22 as a function of transverse momentum (pT) are also presented. A systematic comparison of the Fourier coefficients for the two systems U+U and Au+Au is discussed.

  16. From the Ternary Eu(Au/In)2 and EuAu4(Au/In)2 with Remarkable Au/In Distributions to a New Structure Type: The Gold-Rich Eu5Au16(Au/In)6 Structure.

    PubMed

    Steinberg, Simon; Card, Nathan; Mudring, Anja-Verena

    2015-09-01

    The ternary Eu(Au/In)2 (EuAu(0.46)In(1.54(2))) (I), EuAu4(Au/In)2 (EuAu(4+x)In(2-x) with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu5Au16(Au/In)6 (Eu5Au(17.29)In(4.71(3))) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl4Mo2-type (tI14; I4/mmm; Z = 2; a = 7.1612(7) Å; c = 5.5268(7) Å) and exhibit significant Au/In disorder. I is composed of an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squared Au8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu5Au16(Au/In)6 (Eu5Au(17.29)In(4.71(3))) (oS108; Cmcm; Z = 4; a = 7.2283(4) Å; b = 9.0499(6) Å; c = 34.619(2) Å), which formally represents a one-dimensional intergrowth of the series EuAu2-"EuAu4In2". The site preferences of the disordered Au/In positions in II were investigated for different hypothetical "EuAu4(Au/In)2" models using the projector-augmented wave method and indicate that these structures attempt to optimize the frequencies of the heteroatomic Au-In contacts. A chemical bonding analysis on two "EuAu5In" and "EuAu4In2" models employed the TB-LMTO-ASA method and reveals that the subtle interplay between the local atomic environments and the bond energies determines the structural and site preferences for these systems. PMID:26270622

  17. Centrality dependence of direct photon production in (square root)S(NN) = 200 GeV Au + Au collisions.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Perdekamp, M Grosse; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2005-06-17

    The first measurement of direct photons in Au + Au collisions at (square root)S(NN) = 200 GeV is presented. The direct photon signal is extracted as a function of the Au + Au collision centrality and compared to next-to-leading order perturbative quantum chromodynamics calculations. The direct photon yield is shown to scale with the number of nucleon-nucleon collisions for all centralities. PMID:16090462

  18. Spectra and elliptic flow for Λ, Ξ, and Ω in 200 A GeV Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Zhu, Xiangrong; Song, Huichao

    2016-01-01

    Using VISHNU hybrid model, we calculate the pT-spectra and elliptic flow of Λ, Ξ, and Ω in 200 A GeV Au+Au collisions. Comparisons with the STAR measurements show that the model generally describes these soft hadron data. We also briefly study and discuss the mass ordering of elliptic flow among π, K, p, Λ, Ξ, and Ω in minimum bias Au+Au collisions.

  19. AU-FREDI - AUTONOMOUS FREQUENCY DOMAIN IDENTIFICATION

    NASA Technical Reports Server (NTRS)

    Yam, Y.

    1994-01-01

    The Autonomous Frequency Domain Identification program, AU-FREDI, is a system of methods, algorithms and software that was developed for the identification of structural dynamic parameters and system transfer function characterization for control of large space platforms and flexible spacecraft. It was validated in the CALTECH/Jet Propulsion Laboratory's Large Spacecraft Control Laboratory. Due to the unique characteristics of this laboratory environment, and the environment-specific nature of many of the software's routines, AU-FREDI should be considered to be a collection of routines which can be modified and reassembled to suit system identification and control experiments on large flexible structures. The AU-FREDI software was originally designed to command plant excitation and handle subsequent input/output data transfer, and to conduct system identification based on the I/O data. Key features of the AU-FREDI methodology are as follows: 1. AU-FREDI has on-line digital filter design to support on-orbit optimal input design and data composition. 2. Data composition of experimental data in overlapping frequency bands overcomes finite actuator power constraints. 3. Recursive least squares sine-dwell estimation accurately handles digitized sinusoids and low frequency modes. 4. The system also includes automated estimation of model order using a product moment matrix. 5. A sample-data transfer function parametrization supports digital control design. 6. Minimum variance estimation is assured with a curve fitting algorithm with iterative reweighting. 7. Robust root solvers accurately factorize high order polynomials to determine frequency and damping estimates. 8. Output error characterization of model additive uncertainty supports robustness analysis. The research objectives associated with AU-FREDI were particularly useful in focusing the identification methodology for realistic on-orbit testing conditions. Rather than estimating the entire structure, as is

  20. Three views of two giant streams: Aligned observations at 1 AU, 4.6 AU, and 5.9 AU

    NASA Technical Reports Server (NTRS)

    Siscoe, George; Intriligator, Devrie

    1993-01-01

    A close radial alignment of the Interplanetary Monitoring Platform (IMP) and Pioneers 10 and 11 spacecraft in 1974 allows a nearly unambiguous, empirical study of the radial evolution of the interaction regions of two contrasting weak and strong, giant streams. The study confirms the main aspects of the standard model of corotating interaction regions: an expanding and strengthening pair of forward-reverse shocks sandwich a stream interface. It adds the follwoing concepts: stream group speed--the speed at the stream interface tends to remain constant with distance; corotating stream complexes--interaction regions can include features like noncompressive density enhancements and streamer belts; secondary interfaces--a possible precursor to the reverse shock; and emerging stream interfaces--one emerged between 1 AU and 4.6 AU. The study uses the conservation specific entropy to correlate features between spacecraft.

  1. Di-hadron correlations with identified leading hadrons in 200 GeV Au + Au and d + Au collisions at STAR

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Bai, X.; Bairathi, V.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, X.; Chen, J. H.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, T.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jia, J.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, W.; Li, Z. M.; Li, Y.; Li, C.; Li, X.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Ma, R.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, Y.; Sun, Z.; Sun, X. M.; Sun, X.; Surrow, B.; Svirida, D. N.; Szelezniak, M. A.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Tawfik, A.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, J. S.; Wang, F.; Wang, H.; Wang, G.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Wu; Xiao, Z. G.; Xie, W.; Xin, K.; Xu, H.; Xu, Z.; Xu, Q. H.; Xu, Y. F.; Xu, N.; Yang, S.; Yang, Y.; Yang, Q.; Yang, Y.; Yang, C.; Yang, Y.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, Y.; Zhang, Z.; Zhang, J. B.; Zhang, J.; Zhang, X. P.; Zhang, S.; Zhang, J.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.

    2015-12-01

    The STAR Collaboration presents for the first time two-dimensional di-hadron correlations with identified leading hadrons in 200 GeV central Au + Au and minimum-bias d + Au collisions to explore hadronization mechanisms in the quark gluon plasma. The enhancement of the jet-like yield for leading pions in Au + Au data with respect to the d + Au reference and the absence of such an enhancement for leading non-pions (protons and kaons) are discussed within the context of a quark recombination scenario. The correlated yield at large angles, specifically in the ridge region, is found to be significantly higher for leading non-pions than pions. The consistencies of the constituent quark scaling, azimuthal harmonic model and a mini-jet modification model description of the data are tested, providing further constraints on hadronization.

  2. From the ternary Eu(Au/In)2 and EuAu4(Au/In)2 with remarkable Au/In distributions to a new structure type: The gold-rich Eu5Au16(Au/In)6 structure

    DOE PAGESBeta

    Steinberg, Simon; Card, Nathan; Mudring, Anja -Verena

    2015-08-13

    The ternary Eu(Au/In)2 (EuAu0.46In1.54(2)) (I), EuAu4(Au/In)2 (EuAu4+xIn2–x with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu5Au16(Au/In)6 (Eu5Au17.29In4.71(3)) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl4Mo2-type (tI14; I4/mmm; Z = 2; a = 7.1612(7) Å; c = 5.5268(7) Å) and exhibit significant Au/In disorder. I is composed of an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squaredmore » Au8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu5Au16(Au/In)6 (Eu5Au17.29In4.71(3)) (oS108; Cmcm; Z = 4; a = 7.2283(4) Å; b = 9.0499(6) Å; c = 34.619(2) Å), which formally represents a one-dimensional intergrowth of the series EuAu2–“EuAu4In2”. The site preferences of the disordered Au/In positions in II were investigated for different hypothetical “EuAu4(Au/In)2” models using the projector-augmented wave method and indicate that these structures attempt to optimize the frequencies of the heteroatomic Au–In contacts. Furthermore, a chemical bonding analysis on two “EuAu5In” and “EuAu4In2” models employed the TB-LMTO-ASA method and reveals that the subtle interplay between the local atomic environments and the bond energies determines the structural and site preferences for these systems.« less

  3. Enhanced spin pumping at yttrium iron garnet/Au interfaces

    SciTech Connect

    Burrowes, C.; Heinrich, B.; Kardasz, B.; Montoya, E. A.; Girt, E.; Sun Yiyan; Song, Young-Yeal; Wu Mingzhong

    2012-02-27

    Spin injection across the ferrimagnetic insulator yttrium iron garnet (YIG)/normal metal Au interface was studied using ferromagnetic resonance. The spin mixing conductance was determined by comparing the Gilbert damping parameter {alpha} in YIG/Au and YIG/Au/Fe heterostructures. The main purpose of this study was to correlate the spin pumping efficiency with chemical modifications of the YIG film surface using in situ etching and deposition techniques. By means of Ar{sup +} ion beam etching, one is able to increase the spin mixing conductance at the YIG/Au interface by a factor of 5 compared to the untreated YIG/Au interface.

  4. Thermal Desorption of Au from W(001) Surface

    NASA Astrophysics Data System (ADS)

    Błaszczyszyn, R.; Chrzanowski, J.; Godowski, P. J.

    2000-12-01

    Adsorption of Au on W(001) at 450 K up to multilayer structures was investigated. Temperature programmed desorption technique was used in determination of coverage dependent desorption energy (region up to one monolayer). Results were discussed in terms of competitive interactions of Au--Au and Au--W atoms. Simple procedure for prediction of faceting behavior on the interface, basing on the desorption data, was postulated. It was deduced that the Au/W(001) interface should not show faceting tendency after thermal treatment.

  5. First results on d+Au collisions from PHOBOS

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Becker, B.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harrington, A. S.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lee, J. W.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Noell, A.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Roland, C.; Roland, G.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Teng, R.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.; Zhang, J.

    2004-02-01

    We have measured transverse momentum distributions of charged hadrons produced in d+Au collisions at √SNN = 200 GeV, in the range 0.25 < pT < 6.0 GeV/c. With increasing collision centrality, the yield at high transverse momenta increases more rapidly than the overall particle density, leading to a strong modification of the spectral shape. This change in spectral shape is qualitatively different from observations in Au+Au collisions at the same energy. The results provide important information for discriminating between different models for the suppression of high-pT hadrons observed in Au+Au collisions.

  6. Surface effects on the radiation response of nanoporous Au foams

    SciTech Connect

    Fu, E. G.; Caro, M.; Wang, Y. Q.; Baldwin, K.; Caro, A.; Zepeda-Ruiz, L. A.; Bringa, E.; Nastasi, M.

    2012-11-05

    We report on an experimental and simulation campaign aimed at exploring the radiation response of nanoporous Au (np-Au) foams. We find different defect accumulation behavior by varying radiation dose-rate in ion-irradiated np-Au foams. Stacking fault tetrahedra are formed when np-Au foams are irradiated at high dose-rate, but they do not seem to be formed in np-Au at low dose-rate irradiation. A model is proposed to explain the dose-rate dependent defect accumulation based on these results.

  7. Synthesis, structure, and bonding in K12Au21Sn4. A polar intermetallic compound with dense Au20 and open AuSn4 layers

    SciTech Connect

    Li, Bin; Kim, Sung-Jin; Miller, Gordon J.; and Corbett, John D.

    2009-10-29

    The new phase K{sub 12}Au{sub 21}Sn{sub 4} has been synthesized by direct reaction of the elements at elevated temperatures. Single crystal X-ray diffraction established its orthorhombic structure, space group Pmmn (No. 59), a = 12.162(2); b = 18.058(4); c = 8.657(2) {angstrom}, V = 1901.3(7) {angstrom}{sup 3}, and Z = 2. The structure consists of infinite puckered sheets of vertex-sharing gold tetrahedra (Au{sub 20}) that are tied together by thin layers of alternating four-bonded-Sn and -Au atoms (AuSn{sub 4}). Remarkably, the dense but electron-poorer blocks of Au tetrahedra coexist with more open and saturated Au-Sn layers, which are fragments of a zinc blende type structure that maximize tetrahedral heteroatomic bonding outside of the network of gold tetrahedra. LMTO band structure calculations reveal metallic properties and a pseudogap at 256 valence electrons per formula unit, only three electrons fewer than in the title compound and at a point at which strong Au-Sn bonding is optimized. Additionally, the tight coordination of the Au framework atoms by K plays an important bonding role: each Au tetrahedra has 10 K neighbors and each K atom has 8-12 Au contacts. The appreciably different role of the p element Sn in this structure from that in the triel members in K{sub 3}Au{sub 5}In and Rb{sub 2}Au{sub 3}Tl appears to arise from its higher electron count which leads to better p-bonding (valence electron concentrations = 1.32 versus 1.22).

  8. Isomorphism and solid solutions among Ag- and Au-selenides

    NASA Astrophysics Data System (ADS)

    Palyanova, Galina A.; Seryotkin, Yurii V.; Kokh, Konstantin A.; Bakakin, Vladimir V.

    2016-09-01

    Au-Ag selenides were synthesized by heating stoichiometric mixtures of elementary substances of initial compositions Ag2-xAuxSe with a step of x=0.25 (0≤x≤2) to 1050 °C and annealing at 500 °C. Scanning electron microscopy, optical microscopy, electron microprobe analysis and X-ray powder diffraction methods have been applied to study synthesized samples. Results of studies of synthesized products revealed the existence of three solid solutions with limited isomorphism Ag↔Au: naumannite Ag2Se - Ag1.94Au0.06Se, fischesserite Ag3AuSe2 - Ag3.2Au0.8Se2 and gold selenide AuSe - Au0.94Ag0.06Se. Solid solutions and AgAuSe phases were added to the phase diagram of Ag-Au-Se system. Crystal-chemical interpretation of Ag-Au isomorphism in selenides was made on the basis of structural features of fischesserite, naumannite, and AuSe.

  9. Direct Observation of Au Nanoclusters at Au/Si Interface and Enhanced SiO2 Growth Due to Catalytic Action by Au in Thermally Oxidized Au-Precipitated n-Type Si(001) Surfaces

    NASA Astrophysics Data System (ADS)

    Shimizu, Hirofumi; Kumamoto, Akihito; Imamura, Senji

    2013-04-01

    The behavior of Au nanoclusters at a Au/n-Si interface was investigated. In particular, SiO2 growth in thermally oxidized Au-precipitated n-type Si(001) surfaces was enhanced by the catalytic action of Au. When the Au-precipitated Si wafer was exposed to air for 30 d at room temperature (RT), a SiO2 film layer grew over Au nanoclusters on the Si surface. This is possibly because Si atoms may diffuse in an as-deposited Au layer and are oxidized in air at RT. In the case of oxidation at higher temperatures (850 °C for 30 min), Au nanoclusters were found to exist at the Au/n-Si interface. Moreover, the origin of protuberances observed by atomic force microscopy was found to be a bulge in the SiO2 film formed over the Au nanocluster, proving that the growth of the SiO2 film layer was enhanced by the catalytic action of Au.

  10. [Gold antirheumatic drug: desired and adverse effects of Au(I) and Au(III) [corrected] on the immune system.

    PubMed

    Griem, P; Gleichmann, E

    1996-01-01

    Three new findings are reviewed that help to understand the mechanisms of action of anti-rheumatic gold drugs, such as disodium aurothiomalate (Na2Au(I)TM): i) We found that Na2Au(I)TM selectively inhibits T-cell receptor-mediated antigen recognition by murine CD4+ T-cell hybridomas specific for antigenic peptides containing at least two cysteine residues. Presumably, Au(I) acts as a chelating agent forming linear complexes (Cys-Au(I)-Cys) which prevents correct antigen-processing and/or peptide recognition by the T-cell receptor, ii) We were able to show that Au(I) is oxidized to Au(III) in mononuclear phagocytes, such as macrophages. Because Au(III) rapidly oxidizes protein and itself is re-reduced to Au(I), this may introduce an Au(I)/Au(III) redox system into phagocytes which scavenges reactive oxygen species, such as hypochlorous acid (HOCl) and inactivates lysosomal enzymes, iii) Pretreatment with Au(III) of a model protein antigen, bovine ribonuclease A (RNase A), induced novel antigenic determinants recognized by CD4+ T lymphocytes. Analysis of the fine specificity of these "Au(III)-specific" T-cells revealed that they react to RNase peptides that are not presented to T-cells when the native protein, i.e., not treated with Au(III), is used as antigen. The T-cell recognition of these cryptic peptides did not require the presence of gold. This finding has important implications for understanding the pathogenesis of allergic and autoimmune responses induced by gold drugs. Taken together, our findings indicate that Au(I) and Au(III) each exert specific effects on several distinct functions of macrophages and the activation of T-cells. These effects may explain both the desired anti-inflammatory and the adverse effects of antirheumatic gold drugs. PMID:9036720

  11. Au-nanoparticles grafted on plasma treated PE

    NASA Astrophysics Data System (ADS)

    Švorčík, V.; Chaloupka, A.; Řezanka, P.; Slepička, P.; Kolská, Z.; Kasálková, N.; Hubáček, T.; Siegel, J.

    2010-03-01

    Polyethylene (PE) surface was treated with Ar plasma. Activated surface was grafted from methanol solution of 1,2-ethanedithiol. Then the sample was immersed into freshly prepared colloid solution of Au-nanoparticles. Finally Au layer was sputtered on the samples. Properties of the modified PE were studied using various methods: AFM, EPR, RBS and nanoindentation. It was shown that the plasma treatment results in degradation of polymer chain (AFM) and creation of free radicals by EPR. After grafting with dithiol, the concentration of free radicals declines. The presence of Au and S in the surface layer after the coating with Au-nanoparticles was proved by RBS. Plasma treatment changes PE surface morphology and increases surface roughness, too. Another significant change in surface morphology and roughness was observed after deposition of Au-nanoparticles. Nanoindentation measurements show that the grafting with Au-nanoparticles increases adhesion of subsequently sputtered Au layer.

  12. Collision-spike Sputtering of Au Nanoparticles.

    PubMed

    Sandoval, Luis; Urbassek, Herbert M

    2015-12-01

    Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For the particular case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31 % of the impact energy remains in the nanoparticles after impact; the remainder is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80 % of that of free nanoparticles due to the suppression of forward sputtering. PMID:26245857

  13. Collision-spike sputtering of Au nanoparticles

    SciTech Connect

    Sandoval, Luis; Urbassek, Herbert M.

    2015-08-06

    Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For this specific case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31% of the impact energy remains in the nanoparticles after impact; the remainder is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80% of that of free nanoparticles due to the suppression of forward sputtering.

  14. Collision-spike sputtering of Au nanoparticles

    DOE PAGESBeta

    Sandoval, Luis; Urbassek, Herbert M.

    2015-08-06

    Ion irradiation of nanoparticles leads to enhanced sputter yields if the nanoparticle size is of the order of the ion penetration depth. While this feature is reasonably well understood for collision-cascade sputtering, we explore it in the regime of collision-spike sputtering using molecular-dynamics simulation. For this specific case of 200-keV Xe bombardment of Au particles, we show that collision spikes lead to abundant sputtering with an average yield of 397 ± 121 atoms compared to only 116 ± 48 atoms for a bulk Au target. Only around 31% of the impact energy remains in the nanoparticles after impact; the remaindermore » is transported away by the transmitted projectile and the ejecta. The sputter yield of supported nanoparticles is estimated to be around 80% of that of free nanoparticles due to the suppression of forward sputtering.« less

  15. Tunable VO2/Au hyperbolic metamaterial

    NASA Astrophysics Data System (ADS)

    Prayakarao, S.; Mendoza, B.; Devine, A.; Kyaw, C.; van Dover, R. B.; Liberman, V.; Noginov, M. A.

    2016-08-01

    Vanadium dioxide (VO2) is known to have a semiconductor-to-metal phase transition at ˜68 °C. Therefore, it can be used as a tunable component of an active metamaterial. The lamellar metamaterial studied in this work is composed of subwavelength VO2 and Au layers and is designed to undergo a temperature controlled transition from the optical hyperbolic phase to the metallic phase. VO2 films and VO2/Au lamellar metamaterial stacks have been fabricated and studied in electrical conductivity and optical (transmission and reflection) experiments. The observed temperature-dependent changes in the reflection and transmission spectra of the metamaterials and VO2 thin films are in a good qualitative agreement with theoretical predictions. The demonstrated optical hyperbolic-to-metallic phase transition is a unique physical phenomenon with the potential to enable advanced control of light-matter interactions.

  16. Analysis of the residual linewidth in electron-paramagnetic resonance of AuEr and AuYb

    NASA Astrophysics Data System (ADS)

    Spalden, Y. von; Baberschke, K.

    1981-04-01

    For single crystals of AuEr and polycrystalline AuYb the residual EPR linewidth due to inhomogeneous broadening is analyzed. Angular dependent experiments show uniquely that the main contribution is due to internal strain rather than to dipolar interaction. The independent experiments for AuEr and AuYb yield a consistent set of parameters but show a dipolar contribution two to three times smaller than calculated. An explanation for this is given. The very precise determination of Hres yields |Δg | = |ρJ1| < 0.005 for AuEr, a vanishing g-shift.

  17. Thermal stability of sputtered intermetallic Al-Au coatings

    SciTech Connect

    Moser, M.; Mayrhofer, P. H.; Ross, I. M.; Rainforth, W. M.

    2007-09-15

    Recently, the authors have shown that single-phase Al{sub 2}Au coatings, prepared by unbalanced magnetron sputtering, exhibit a dense columnar structure and highest hardness and indentation moduli of 8 and 144 GPa, respectively, within the Al-Au films investigated. This study focuses on the thermal stability of Al{sub 2}Au with respect to films containing more Al and Au having Al/Au at. % ratios of 4.32 and 1.85, respectively. Single-phase Al{sub 2}Au has the highest onset temperature for recovery of 475 deg. C and recrystallization of 575 deg. C. Upon annealing Au- and Al-rich films, their stresses deviate from the linear thermoelastic behavior at temperatures (T) above 200 and 450 deg. C, respectively, due to pores and metallic phases present. Metastable Au within the as-deposited Au-rich film is consumed by the growing intermetallic AlAu and AlAu{sub 2} phases at T{>=}450 deg. C, which themselves melt at {approx}625 deg. C. Due to nanometer scale segregations of Al, encapsulated by Al{sub 2}Au in Al-rich coatings, their melting point is reduced by {approx}85 deg. C to 575 deg. C. Dynamic thermal analyses up to 1100 deg. C in synthetic air reveal the single-phase Al{sub 2}Au films with a superior thermal stability and only negligible oxidation. At 750 deg. C, the mass gain is {approx}1.5 mg/cm{sup 2} after 50 h isothermal exposure. Based on the investigations, the authors can conclude that single-phase intermetallic Al{sub 2}Au films have a high potential for oxidation protection of sensitive materials.

  18. Assembly of hybrid oligonucleotide modified gold (Au) and alloy nanoparticles building blocks.

    PubMed

    Kuo, Yu-Ching; Jen, Chun-Ping; Chen, Yu-Hung; Su, Chia-Hao; Tsai, Shu-Hui; Yeh, Chen-Sheng

    2006-01-01

    The alloy-based hybrid materials with macroscopic network arrays were developed by AuAg/Au and AuAgPd/Au nanoparticle composites through oligonucleotides hybridization. AuAg/Au and AuAgPd/Au exhibited distinct organization. The morphology of AuAg/Au conjugation assembled mainly as compact aggregates while AuAgPd/Au hybrid conjugated into the loosen network assemblies. The dehybridization temperatures were studied as a function of molar ratio of alloy/Au. It was found that higher alloy/gold molar ratio led to stronger hybridization for alloy/gold composite, accompanied with increased melting temperature. These results could be interpreted in terms of more alloy nanoparticles bound to a Au particle when the molar ratio of alloy/gold increased. The thermal analysis also showed that AuAg/Au exhibited higher dehybridization temperature. A modified model describing the dehybridization probability of an intact Au/alloy aggregate was performed to support the dehybridization temperature increased with increasing alloy/Au molar ratio. As to more oligonucleotides carried by AuAg (4.9 +/- 1.9 nm) than by AuAgPd (4.4 +/- 1.5 nm) due to larger size in AuAg, the efficient hybridization could result in higher dehybridization temperature in AuAg/Au. PMID:16573077

  19. Analyse des facteurs histo-pronostiques du cancer du rectum non métastatique dans une série ouest Algérienne de 58 cas au CHU-Tlemcen

    PubMed Central

    Mesli, Smain Nabil; Regagba, Derbali; Tidjane, Anisse; Benkalfat, Mokhtar; Abi-Ayad, Chakib

    2016-01-01

    Introduction L'objectif de notre travail est d'analyser les facteurs histo-pronostiques des cancers du rectum non métastatique opérés au service de chirurgie «A» de Tlemcen à ouest Algérien durant une période de six ans. Méthodes Etude rétrospective de 58 patients qui avait un adénocarcinome rectal. Le critère de jugement était la survie. Les paramètres étudiés, le sexe, l’âge, stade tumoral, et les récidives tumorales. Résultats L’âge moyen était de 58 ans. Avec 52% d'hommes contre 48% femmes avec sex-ratio (1,08). Le siège tumoral était: moyen rectum avec 41,37%, 34,48% au bas rectum et dans 24,13% au haut rectum. La classification TNM avec 17,65% au stade I, 18,61% au stade II, 53, 44% au stade III et 7,84% au stade IV. La survie médiane globale était de 40 mois ±2,937 mois. La survie en fonction du stade tumoral, le stade III et IV avait un faible taux de survie (19%) a 3 ans contre le stade I, II avait un taux de survie de (75%) (P = 0,000) (IC 95%). Les patients avec récidives tumorales avaient un taux de survie faible à 3 ans par rapport à ceux n'ayant pas eu de récidive (30,85% Vs 64,30% P = 0,043). Conclusion Dans cette série, l’étude uni varié des différents facteurs pronostiques conditionnant la survie n'a permis de retenir que trois facteurs influençant la survie, à savoir la taille tumorale, le stade, et les récidives tumorales. En analyse multi variée en utilisant le modèle Cox un seul facteur été retenu la récidive tumorale.

  20. Unwinding Au(+)···Au(+) Bonded Filaments in Ligand-Supported Gold(I) Polymer under Pressure.

    PubMed

    Paliwoda, Damian; Wawrzyniak, Paulina; Katrusiak, Andrzej

    2014-07-01

    The ultimately thin single-strand gold filaments, of Au(+)···Au(+) bonded gold(I) diethyldithiocarbamate polymer, AuEt2DTC, can be transformed depending on pressure and solvate contents. When synthesized in the presence of CH2Cl2, it crystallizes into a tetragonal AuEt2DTC·xCH2Cl2 phase α with ligand-supported and unsupported Au(+)···Au(+) bonded filaments modulated into molecular Au8-pitch helices. Low contents of CH2Cl2 favors the β phase of significantly reduced volume and orthorhombic space group Fddd. The α-AuEt2DTC·xCH2Cl2 crystal exhibits a highly unusual negative-area compressibility, due to the spring-like compression of helices. Above 0.05 GPa, the crystal transforms to phase β, where the Au16-pitch helices partly unwind their turns, which relaxes the tension generated by external pressure between neighboring helices of the opposite handedness. This is a unique observation of atomic-scale helical filaments transformation, which otherwise is a universal process analogous to the helix reversal between DNA forms B and Z, and in macroscopic world it is similar to nonperiodic unwind kinks in grapevine tendrils and telephone cords. Pressure also reduces the differences between the ligand-supported and unsupported Au(+)···Au(+) bonds. PMID:26279531

  1. Virus-templated Au and Au/Pt Core/shell Nanowires and Their Electrocatalytic Activitives for Fuel Cell Applications

    PubMed Central

    LEE, YOUJIN; KIM, JUNHYUNG; YUN, DONG SOO; NAM, YOON SUNG; SHAO-HORN, YANG; BELCHER, ANGELA M.

    2014-01-01

    A facile synthetic route was developed to make Au nanowires (NWs) from surfactant-mediated bio-mineralization of a genetically engineered M13 phage with specific Au binding peptides. From the selective interaction between Au binding M13 phage and Au ions in aqueous solution, Au NWs with uniform diameter were synthesized at room temperature with yields greater than 98 % without the need for size selection. The diameters of Au NWs were controlled from 10 nm to 50 nm. The Au NWs were found to be active for electrocatalytic oxidation of CO molecules for all sizes, where the activity was highly dependent on the surface facets of Au NWs. This low-temperature high yield method of preparing Au NWs was further extended to the synthesis of Au/Pt core/shell NWs with controlled coverage of Pt shell layers. Electro-catalytic studies of ethanol oxidation with different Pt loading showed enhanced activity relative to a commercial supported Pt catalyst, indicative of the dual functionality of Pt for the ethanol oxidation and Au for the anti-poisoning component of Pt. These new one-dimensional noble metal NWs with controlled compositions could facilitate the design of new alloy materials with tunable properties. PMID:24910712

  2. Simulation of Electric Field in Semi Insulating Au/CdTe/Au Detector under Flux

    SciTech Connect

    Franc, J.; James, R.; Grill, R.; Kubat, J.; Belas, E.; Hoschl, P.; Moravec, P.; Praus, P.

    2009-08-02

    We report our simulations on the profile of the electric field in semi insulating CdTe and CdZnTe with Au contacts under radiation flux. The type of the space charge and electric field distribution in the Au/CdTe/Au structure is at high fluxes result of a combined influence of charge formed due to band bending at the electrodes and from photo generated carriers, which are trapped at deep levels. Simultaneous solution of drift-diffusion and Poisson equations is used for the calculation. We show, that the space charge originating from trapped photo-carriers starts to dominate at fluxes 10{sup 15}-10{sup 16}cm{sup -2}s{sup -1}, when the influence of contacts starts to be negligible.

  3. Admittance of Au/1,4-benzenedithiol/Au single-molecule junctions

    NASA Astrophysics Data System (ADS)

    Yamauchi, Kazumasa; Kurokawa, Shu; Sakai, Akira

    2012-12-01

    Employing the admittance formula for double-barrier junctions [Fu and Dudley, Phys. Rev. Lett. 70, 65 (1993)], we have estimated an ac susceptance (imaginary part of admittance) of Au/1,4-benzenedithiol/Au single-molecule junctions from their current-voltage characteristics. In the MHz regime, we find that the junction susceptance shows a very small (˜0.1 aF) capacitive component that can be entirely masked by a larger electrode capacitance. Direct ac signal transmission measurements up to 1 GHz reveal no molecular signals and confirm the smallness of the molecular capacitance in the MHz regime.

  4. Net charge fluctuations in Au + Au interactions at sqrt[s(NN)]=130 GeV.

    PubMed

    Adcox, K; Adler, S S; Ajitanand, N N; Akiba, Y; Alexander, J; Aphecetche, L; Arai, Y; Aronson, S H; Averbeck, R; Awes, T C; Barish, K N; Barnes, P D; Barrette, J; Bassalleck, B; Bathe, S; Baublis, V; Bazilevsky, A; Belikov, S; Bellaiche, F G; Belyaev, S T; Bennett, M J; Berdnikov, Y; Botelho, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J; Butsyk, S; Carey, T A; Chand, P; Chang, J; Chang, W C; Chavez, L L; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choudhury, R K; Christ, T; Chujo, T; Chung, M S; Chung, P; Cianciolo, V; Cole, B A; D'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Dinesh, B V; Drees, A; Durum, A; Dutta, D; Ebisu, K; Efremenko, Y V; El Chenawi, K; En'yo, H; Esumi, S; Ewell, L; Ferdousi, T; Fields, D E; Fokin, S L; Fraenkel, Z; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Godoi, A L; Goto, Y; Greene, S V; Grosse Perdekamp, M; Gupta, S K; Guryn, W; Gustafsson, H-A; Haggerty, J S; Hamagaki, H; Hansen, A G; Hara, H; Hartouni, E P; Hayano, R; Hayashi, N; He, X; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Ho, D S; Homma, K; Hong, B; Hoover, A; Ichihara, T; Imai, K; Ippolitov, M S; Ishihara, M; Jacak, B V; Jang, W Y; Jia, J; Johnson, B M; Johnson, S C; Joo, K S; Kametani, S; Kang, J H; Kann, M; Kapoor, S S; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D J; Kim, H J; Kim, S Y; Kim, Y G; Kinnison, W W; Kistenev, E; Kiyomichi, A; Klein-Boesing, C; Klinksiek, S; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kotchetkov, D; Kozlov, A; Kroon, P J; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lajoie, J G; Lauret, J; Lebedev, A; Lee, D M; Leitch, M J; Li, X H; Li, Z; Lim, D J; Liu, M X; Liu, X; Liu, Z; Maguire, C F; Mahon, J; Makdisi, Y I; Manko, V I; Mao, Y; Mark, S K; Markacs, S; Martinez, G; Marx, M D; Masaike, A; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Merschmeyer, M; Messer, F; Messer, M; Miake, Y; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagasaka, Y; Nagle, J L; Nakada, Y; Nandi, B K; Newby, J; Nikkinen, L; Nilsson, P; Nishimura, S; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Ono, M; Onuchin, V; Oskarsson, A; Osterman, L; Otterlund, I; Oyama, K; Paffrath, L; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Pate, S F; Peitzmann, T; Petridis, A N; Pinkenburg, C; Pisani, R P; Pitukhin, P; Plasil, F; Pollack, M; Pope, K; Purschke, M L; Ravinovich, I; Read, K F; Reygers, K; Riabov, V; Riabov, Y; Rosati, M; Rose, A A; Ryu, S S; Saito, N; Sakaguchi, A; Sakaguchi, T; Sako, H; Sakuma, T; Samsonov, V; Sangster, T C; Santo, R; Sato, H D; Sato, S; Sawada, S; Schlei, B R; Schutz, Y; Semenov, V; Seto, R; Shea, T K; Shein, I; Shibata, T-A; Shigaki, K; Shiina, T; Shin, Y H; Sibiriak, I G; Silvermyr, D; Sim, K S; Simon-Gillo, J; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sorensen, S; Stankus, P W; Starinsky, N; Steinberg, P; Stenlund, E; Ster, A; Stoll, S P; Sugioka, M; Sugitate, T; Sullivan, J P; Sumi, Y; Sun, Z; Suzuki, M; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Taniguchi, E; Tannenbaum, M J; Thomas, J; Thomas, J H; Thomas, T L; Tian, W; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tsvetkov, A A; Tuli, S K; Tydesjö, H; Tyurin, N; Ushiroda, T; van Hecke, H W; Velissaris, C; Velkovska, J; Velkovsky, M; Vinogradov, A A; Volkov, M A; Vorobyov, A; Vznuzdaev, E; Wang, H; Watanabe, Y; White, S N; Witzig, C; Wohn, F K; Woody, C L; Xie, W; Yagi, K; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, Z; Zhou, S

    2002-08-19

    Data from Au + Au interactions at sqrt[s(NN)]=130 GeV, obtained with the PHENIX detector at the Relativistic Heavy-Ion Collider, are used to investigate local net charge fluctuations among particles produced near midrapidity. According to recent suggestions, such fluctuations may carry information from the quark-gluon plasma. This analysis shows that the fluctuations are dominated by a stochastic distribution of particles, but are also sensitive to other effects, like global charge conservation and resonance decays. PMID:12190459

  5. Domain wall dynamics in a spin-reorientation transition system Au/Co/Au

    SciTech Connect

    Roy, Sujoy; Seu, Keoki; Turner, Joshua J.; Park, Sungkyun; Kevan, Steve; Falco, Charles M.

    2009-05-14

    We report measurements of domain wall dynamics in an ultrathin Au/Co/Au system that exhibits a spin reorientation phase transition as a function of temperature.The domain walls exhibit cooperative motion throughout the temperature range of 150 - 300 K. The decay times were found to exhibit a maximum at the transition temperature. The slowdown has been explained as due to formation of a double well in the energy landscape by the different competing interactions. Our results show that the complex, slow dynamics can provide a more fundamental understanding of magnetic phase transitions.

  6. Measuring away-side jet modifications in Au+Au collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Jiang, Kun; STAR Collaboration

    2015-08-01

    We report measurements of jet correlations in Au+Au collisions at = 200 GeV by the STAR experiment. In this analysis we devise a novel method to subtract flow background using data itself. The correlation width is studied as a function of centrality and associated particle pTT. The width is found to increase with centrality at modest to high associated particle pTT. The increase can arise from jet modification by medium and/or event averaging of away-side jets deflected by medium flow. The discrimination of the physics mechanisms requires further study by three-particle correlations.

  7. Energy Dependence of Particle Multiplicities in Central Au+Au Collisions

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Corbo, J.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Henderson, C.; Hicks, D.; Hofman, D.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Rafelski, M.; Rbeiz, M.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2002-01-01

    We present the first measurement of the pseudorapidity density of primary charged particles in Au+Au collisions at (sNN) = 200 GeV. For the 6% most central collisions, we obtain dNch/dη\\|\\|η\\|<1 = 650+/-35(syst). Compared to collisions at (sNN) = 130 GeV, the highest energy studied previously, an increase by a factor of 1.14+/-0.05 at 90% confidence level, is found. The energy dependence of the pseudorapidity density is discussed in comparison with data from proton-induced collisions and theoretical predictions.

  8. Beam Energy Scan a Case for the Chiral Magnetic Effect in Au-Au Collisions

    SciTech Connect

    Longacre, R.

    2014-01-05

    The Chiral Magnetic Effect (CME) is predicted for Au-Au collisions at RHIC. However, many backgrounds can give signals that make the measurement hard to interpret. The STAR experiment has made measurements at different collisions energy ranging from √(sNN)=7.7 GeV to 62.4 GeV. In the analysis that is presented we show that the CME turns on with energy and is not present in central collisions where the induced magnetic is small.

  9. Two-Particle Interferometry of 200 GeV Au+Au Collisions at PHENIX

    SciTech Connect

    Heffner, M

    2004-04-19

    The PHENIX experiment has measured pion-pion, kaon-kaon, and proton-proton correlations in Au+Au collisions at {radical}S{sub NN} = 200GeV. The correlations are fit to extract radii using both the Bowler Coulomb correction and full calculation of the two-particle wave function. The resulting radii are similar for all three species and decrease with increasing k{sub t} as expected for collective flow. The R{sub out} and R{sub side} radii are approximately equal indicating a short emission duration.

  10. Onset of nuclear vaporization in [sup 197]Au+[sup 197]Au collisions

    SciTech Connect

    Tsang, M.B.; Hsi, W.C.; Lynch, W.G.; Bowman, D.R.; Gelbke, C.K.; Lisa, M.A.; Peaslee, G.F. ); Kunde, G.J.; Begemann-Blaich, M.L.; Hofmann, T.; Hubele, J.; Kempter, J.; Kreutz, P.; Kunze, W.D.; Lindenstruth, V.; Lynen, U.; Mang, M.; Mueller, W.F.J.; Neumann, M.; Ocker, B.; Ogilvie, C.A.; Pochodzalla, J.; Rosenberger, F.; Sann, H.; Schuettauf, A.; Serfling, V.; Stroth, J.; Trautmann, W.; Tucholski, A.; Woerner, A.; Zude, E.; Zwieglinski, B. ); Aiello, S.; Imme, G.; Pappalardo, V.; Raciti, G. ); Charity, R.J.; Sobotka, L.G. ); Iori, I.; Moroni, A.; Scardoni, R.; Ferr

    1993-09-06

    Multifragmentation has been measured for [sup 197]Au+[sup 197]Au collisions at [ital E]/[ital A]=100, 250, and 400 MeV. The mean fragment multiplicity increases monotonically with the charged particle multiplicity at [ital E]/[ital A]=100 MeV, but decreases for central collisions with incident energy, consistent with the onset of nuclear vaporization. Molecular dynamics calculations follow some trends but underpredict the observed fragment multiplicities. Including the statistical decay of excited residues improves the agreement for peripheral collisions but worsens it for central collisions.

  11. Relativistic multireference many-body perturbation theory calculations on Au64+ - Au69+ ions

    SciTech Connect

    Vilkas, M J; Ishikawa, Y; Trabert, E

    2006-03-31

    Many-body perturbation theory (MBPT) calculations are an adequate tool for the description of the structure of highly charged multi-electron ions and for the analysis of their spectra. They demonstrate this by way of a re-investigation of n=3, {Delta}n=0 transitions in the EUV spectra of Na-, Mg-, Al-like, and Si-like ions of Au that have been obtained previously by heavy-ion accelerator based beam-foil spectroscopy. They discuss the evidence and propose several revisions on the basis of the multi-reference many-body perturbation theory calculations of Ne- through P-like ions of Au.

  12. Initial-state geometry and fluctuations in Au + Au, Cu + Au, and U + U collisions at energies available at the BNL Relativistic Heavy Ion Collider

    NASA Astrophysics Data System (ADS)

    Schenke, Björn; Tribedy, Prithwish; Venugopalan, Raju

    2014-06-01

    We study within the IP-Glasma and two-component MC-Glauber models the effects of initial-state geometry and fluctuations on multiplicities and eccentricities for several collision species at the Relativistic Heavy Ion Collider (RHIC). These include copper-gold (Cu + Au), gold-gold (Au + Au), and uranium-uranium (U + U) collisions. The multiplicity densities per participant pair are very similar in all systems studied. Ellipticities vary strongly between collision systems, most significantly for central collisions, while fluctuation driven odd moments vary little between systems. Event-by-event distributions of eccentricities in mid-central collisions are wider in Cu + Au relative to Au + Au and U + U systems. An anticorrelation between multiplicity and eccentricity is observed in ultracentral U + U collisions which is weaker in the IP-Glasma model than the two-component MC-Glauber model. In ultracentral Au + Au collisions the two models predict opposite signs for the slope of this correlation. Measurements of elliptic flow as a function of multiplicity in such central events can therefore be used to discriminate between models with qualitatively different particle production mechanisms.

  13. Bridging gold in electron-deficient Al2Au(n)(0/-) and BAlAu(n)(0/-) (n = 1-3) clusters.

    PubMed

    Yao, Wen-Zhi; Liu, Bing-Tao; Lu, Zhang-Hui; Li, Si-Dian

    2013-06-20

    The geometrical and electronic structures of the electron-deficient dialuminum aurides Al2Aun(0/-) and hybrid boron-aluminum aurides BAlAun(0/-) (n = 1-3) are systematically investigated based on the density and wave function theories. Ab initio theoretical evidence strongly suggests that bridging gold atoms exist in the ground states of C2v Al2Au(-) ((3)B1), C2v Al2Au ((2)B1), C2v Al2Au2(-) ((2)A1), C2v Al2Au2 ((1)A1), Cs Al2Au3(-) ((1)A'), and D3h Al2Au3 ((2)A1), which prove to possess an Al-Au-Al τ bond. For BAlAun(0/-) (n = 1-3) mixed clusters, bridging B-Au-Al units only exist in Cs BAlAu3(-) ((1)A') and Cs BAlAu3 ((2)A'), whereas Cs BAlAu(-) ((3)A''), Cs BAlAu ((2)A''), Cs BAlAu2(-) ((2)A'), and Cs BAlAu2 ((1)A') do not possess a bridging gold, as demonstrated by the fact that B-Al and B-Au exhibit significantly stronger electronic interaction than Al-Au in the same clusters. Orbital analyses indicate that Au 6s contributes approximately 98%-99% to the Au-based orbital in these Al-Au-Al/B-Au-Al interactions, whereas Au 5d contributes 1%-2%. The adiabatic and vertical detachment energies of Al2Aun(-) (n = 1-3) are calculated to facilitate future experimental characterizations. The results obtained in this work establish an interesting τ bonding model (Al-Au-Al/B-Au-Al) for electron-deficient systems in which Au 6s plays a major factor. PMID:23718624

  14. Cu-Au, Ag-Au, Cu-Ag, and Ni-Au intermetallics: First-principles study of temperature-composition phase diagrams and structures

    NASA Astrophysics Data System (ADS)

    Ozoliņš, V.; Wolverton, C.; Zunger, Alex

    1998-03-01

    The classic metallurgical systems-noble-metal alloys-that have formed the benchmark for various alloy theories are revisited. First-principles fully relaxed general-potential linearized augmented plane-wave (LAPW) total energies of a few ordered structures are used as input to a mixed-space cluster expansion calculation to study the phase stability, thermodynamic properties, and bond lengths in Cu-Au, Ag-Au, Cu-Ag, and Ni-Au alloys. (i) Our theoretical calculations correctly reproduce the tendencies of Ag-Au and Cu-Au to form compounds and Ni-Au and Cu-Ag to phase separate at T=0 K. (ii) Of all possible structures, Cu3Au (L12) and CuAu (L10) are found to be the most stable low-temperature phases of Cu1-xAux with transition temperatures of 530 K and 660 K, respectively, compared to the experimental values 663 K and ~670 K. The significant improvement over previous first-principles studies is attributed to the more accurate treatment of atomic relaxations in the present work. (iii) LAPW formation enthalpies demonstrate that L12, the commonly assumed stable phase of CuAu3, is not the ground state for Au-rich alloys, but rather that ordered (100) superlattices are stabilized. (iv) We extract the nonconfigurational (e.g., vibrational) entropies of formation and obtain large values for the size-mismatched systems: 0.48 kB/atom in Ni0.5Au0.5 (T=1100 K), 0.37 kB/atom in Cu0.141Ag0.859 (T=1052 K), and 0.16 kB/atom in Cu0.5Au0.5 (T=800 K). (v) Using 8 atom/cell special quasirandom structures we study the bond lengths in disordered Cu-Au and Ni-Au alloys and obtain good qualitative agreement with recent extended x-ray-absorption fine-structure measurements.

  15. Electrostatic assembles and optical properties of Au CdTe QDs and Ag/Au CdTe QDs

    NASA Astrophysics Data System (ADS)

    Yang, Dongzhi; Wang, Wenxing; Chen, Qifan; Huang, Yuping; Xu, Shukun

    2008-09-01

    Au-CdTe and Ag/Au-CdTe assembles were firstly investigated through the static interaction between positively charged cysteamine-stabilized CdTe quantum dots (QDs) and negatively charged Au or core/shell Ag/Au nano-particles (NCs). The CdTe QDs synthesized in aqueous solution were capped with cysteamine which endowed them positive charges on the surface. Both Au and Ag/Au NCs were prepared through reducing precursors with gallic acid obtained from the hydrolysis of natural plant poly-phenols and favored negative charges on the surface of NCs. The fluorescence spectra of CdTe QDs exhibited strong quenching with the increase of added Au or Ag/Au NCs. Railey resonance scattering spectra of Au or Ag/Au NCs increased firstly and decreased latter with the concentration of CdTe QDs, accompanied with the solution color changing from red to purple and colorless at last. Experimental results on the effects of gallic acid, chloroauric acid tetrahydrate and other reagents demonstrated the static interaction occurred between QDs and NCs. This finding reveals the possibilities to design and control optical process and electromagnetic coupling in hybrid structures.

  16. Au/Pd core-shell nanoparticles with varied hollow Au cores for enhanced formic acid oxidation

    NASA Astrophysics Data System (ADS)

    Hsu, Chiajen; Huang, Chienwen; Hao, Yaowu; Liu, Fuqiang

    2013-03-01

    A facile method has been developed to synthesize Au/Pd core-shell nanoparticles via galvanic replacement of Cu by Pd on hollow Au nanospheres. The unique nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, ultraviolet-visible spectroscopy, and electrochemical measurements. When the concentration of the Au solution was decreased, grain size of the polycrystalline hollow Au nanospheres was reduced, and the structures became highly porous. After the Pd shell formed on these Au nanospheres, the morphology and structure of the Au/Pd nanoparticles varied and hence significantly affected the catalytic properties. The Au/Pd nanoparticles synthesized with reduced Au concentrations showed higher formic acid oxidation activity (0.93 mA cm-2 at 0.3 V) than the commercial Pd black (0.85 mA cm-2 at 0.3 V), suggesting a promising candidate as fuel cell catalysts. In addition, the Au/Pd nanoparticles displayed lower CO-stripping potential, improved stability, and higher durability compared to the Pd black due to their unique core-shell structures tuned by Au core morphologies.

  17. Au/Pd core-shell nanoparticles with varied hollow Au cores for enhanced formic acid oxidation

    PubMed Central

    2013-01-01

    A facile method has been developed to synthesize Au/Pd core-shell nanoparticles via galvanic replacement of Cu by Pd on hollow Au nanospheres. The unique nanoparticles were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, ultraviolet–visible spectroscopy, and electrochemical measurements. When the concentration of the Au solution was decreased, grain size of the polycrystalline hollow Au nanospheres was reduced, and the structures became highly porous. After the Pd shell formed on these Au nanospheres, the morphology and structure of the Au/Pd nanoparticles varied and hence significantly affected the catalytic properties. The Au/Pd nanoparticles synthesized with reduced Au concentrations showed higher formic acid oxidation activity (0.93 mA cm-2 at 0.3 V) than the commercial Pd black (0.85 mA cm-2 at 0.3 V), suggesting a promising candidate as fuel cell catalysts. In addition, the Au/Pd nanoparticles displayed lower CO-stripping potential, improved stability, and higher durability compared to the Pd black due to their unique core-shell structures tuned by Au core morphologies. PMID:23452438

  18. Le don après un décès d'origine cardiocirculatoire au Canada

    PubMed Central

    Shemie, Sam D.; Baker, Andrew J.; Knoll, Greg; Wall, William; Rocker, Graeme; Howes, Daniel; Davidson, Janet; Pagliarello, Joe; Chambers-Evans, Jane; Cockfield, Sandra; Farrell, Catherine; Glannon, Walter; Gourlay, William; Grant, David; Langevin, Stéphan; Wheelock, Brian; Young, Kimberly; Dossetor, John

    2006-01-01

    Résumé Ces recommandations sont le fruit d'un processus multidisciplinaire national ayant duré un an et visant à déterminer si et comment l'on pourrait procéder au don d'organes après un décès d'origine cardiocirculatoire («don après le décès cardiocirculatoire», ou DDC) au Canada. Le forum national organisé en février 2005 a permis aux participants de discuter et d'élaborer des recommandations sur les principes, interventions et pratiques se rapportant au DDC. Les aspects éthiques et juridiques ont été abordés dans les discussions. À la fin du Forum, la majorité des participants ont été favorables à l'implantation de programmes de DDC au Canada. Les participants du Forum ont également convenu qu'il fallait formuler et prôner des valeurs fondamentales pour orienter l'élaboration de programmes et de protocoles basés sur le cadre médical, éthique et juridique établi lors de cette réunion. Même si la possibilité d'un don d'organes et de tissus doit faire partie intégrante des soins de fin de vie, il faut insister sur le fait que le devoir de diligence envers les patients mourants et leurs familles doit demeurer la priorité des équipes soignantes. La complexité et les répercussions profondes du décès sont reconnues et doivent être respectées, de même que les différences personnelles, ethnoculturelles et religieuses face à la mort et au don d'organes. Les décisions d'arrêter le traitement de maintien des fonctions vitales, la prise en charge des derniers moments de la vie et le diagnostic de décès selon des critères cardiocirculatoires doivent être distincts et indépendants des processus de don et transplantation. Ce rapport contient des recommandations destinées aux gestionnaires de program, aux autorités sanitaires régionales et aux instances appelés à élaborer les protocoles de DDC. Les programmes doivent être conçus en fonction des éléments suivants : direction et planification locales, éducation et

  19. Découverte fortuite de quadruplets au cours d'un accouchement: illustration d'un cas à l'Hôpital Central de Yaoundé (Cameroun)

    PubMed Central

    Fouelifack, Florent Ymele; Fouedjio, Jeanne Hortence; Dingom, Madye Ange Ngo; Fouogue, Jovanny Tsuala; Enow, Robinson Mbu

    2014-01-01

    Les auteurs rapportent une grossesse de haut rang (quadruplés) dont le nombre de fœtus n'a été découvert que pendant l'accouchement par voie vaginale. Faute de moyens, la parturiente reçue en phase active du travail n'a pas pu bénéficier de la césarienne d'urgence indiquée pour présentation en siège du premier jumeau. Ce n'est qu'après l'accouchement du deuxième fœtus que les deux derniers quadruplés ont été successivement découverts. Les difficultés et les pièges contextuels de la prise en charge des grossesses multiples sont passés en revue. Ce cas rappelle au personnel des salles d'accouchement la possibilité d'erreur de diagnostique sur les résultats d'échographies présentés par les parturientes. PMID:25419323

  20. Myélome multiple survenant au cours d'une Fièvre Méditerranéenne Familiale

    PubMed Central

    Salem, Bouomrani; Afef, Farah; Nadia, Bouassida; Nabil, Ayadi; Zouhir, Bahloul; Maher, Béji

    2013-01-01

    L'objectif de ce travail est de rapporter une observation particulière de myélome multiple survenant au cours d'une maladie périodique. Il s'agit d'un patient tunisien de 53 ans suivi depuis le jeune âge pour maladie périodique dont le diagnostic était confirmé par l’étude génétique montrant l'homozygotie pour la mutation M694V du gène MEFV, fut admis pour exploration d'une douleur avec tuméfaction fessière droite récente. Les explorations biologiques et radiologiques ont permis de retenir le diagnostic d'un myélome multiple de type IgA à chaînes légères kappa stade III B, associé à une volumineuse localisation plasmocytaire très agressive de l'aile iliaque droite envahissant les structures musculaires avoisinantes. Notre observation, qui à notre connaissance est la deuxième signalant une telle association, se distingue par sa survenue brutale, sa progression rapide et le caractère très agressif de l'hémopathie. PMID:24255729

  1. Doppler transcranien au cours de la drépanocytose chez l'enfant Malagasy

    PubMed Central

    Herinirina, Nicolas Fanantenana; Rajaonarison, Lova Hasina Ny Ony Narindra; Herijoelison, Andry Roussel; Rakoto, Olivat Aimée Alson; Ahmad, Ahmad

    2016-01-01

    Introduction Le doppler transcrânien est un outil efficace permettant de dépister les enfants drépanocytaires à risque d'AVC. Méthodes Nous avons réalisé une étude descriptive transversale sur des enfants Malagasy âgés entre 24 mois et 15 ans (groupe 1: 57 drépanocytaires, groupe 2: 43 témoins) afin d’évaluer le profil vélocimétrique des artères cérébrales chez les drépanocytaires. Un examen Doppler transcrânien a été réalisé avec étude des flux sanguins cérébraux chez les enfants des deux groupes. Résultats Pour les sujets drépanocytaires, la vitesse moyenne (VM) de l'artère cérébrale moyenne était de 100,9 ± 26,8 cm/s, l'indice de pulsatilité (IP) de 0,73 ± 0,20, la différence entre les artères cérébrales moyennes droite et gauche (ACMr) de 19,8 ± 21,5 cm/s, le rapport des vitesses de l'artère cérébrale antérieure/artère cérébrale moyenne (ACA/ACM) de 0,7 ± 0,2. Pour les enfants non drépanocytaires, VM: 80,6 ± 19,3 cm/s, IP: 0,79 ± 0,14, ACMr: 17 ± 20,1 cm/s, ACA/ACM: 0,8 ± 0,2. La vélocité des enfants drépanocytaires était supérieure au groupe contrôle. Les vitesses ont été corrélées avec le taux d'hémoglobine et l’âge et non pas avec le sexe et le volume globulaire moyen. Conclusion Les vitesses circulatoires cérébrales sont élevées chez les drépanocytaires que les enfants non drépanocytaires et sont influencées par le taux d'hémoglobine et l’âge.

  2. Lateral spreading of Au contacts on InP

    NASA Technical Reports Server (NTRS)

    Fatemi, Navid S.; Weizer, Victor G.

    1990-01-01

    The contact spreading phenomenon observed when small area Au contacts on InP are annealed at temperatures above about 400 C was investigated. It was found that the rapid lateral expansion of the contact metallization which consumes large quantities of InP during growth is closely related to the third stage in the series of solid state reactions that occur between InP and Au, i.e., to the Au3In-to-Au9In4 transition. Detailed descriptions are presented of both the spreading process and the Au3In-to-Au9In4 transition along with arguments that the two processes are manifestations of the same basic phenomenon.

  3. Structural and electronic properties of AuIr nanoalloys

    NASA Astrophysics Data System (ADS)

    Jiménez-Díaz, Laura M.; Pérez, Luis A.

    2013-01-01

    The lowest-energy structures of binary (AuIr) n , (AuIr3) s , and (Au3Ir) s clusters, with n = 2-20, and s = 5, modeled by the many-body Gupta potential, were obtained by using a genetic-symbiotic algorithm. These structures were further relaxed within the density functional theory to obtain the most stable structures for each composition. Segregation is observed in all the AuIr clusters, where the Ir atoms occupy the cluster core and the Au atoms are situated on the cluster surface. On the other hand, there is experimental evidence that the (AuIr) n nanoalloys could have an enhanced catalytic activity for CO oxidation. In order to study this phenomenon, we also performed first-principles density functional calculations of the CO and O2 adsorption on these bimetallic nanoclusters, considering three different compositions and a fixed cluster size of 20 atoms.

  4. Atomic and molecular adsorption on Au(111)

    SciTech Connect

    Santiago-Rodríguez, Yohaselly; Herron, Jeffrey A.; Curet-Arana, María C.; Mavrikakis, Manos

    2014-09-01

    Periodic self-consistent density functional theory (DFT-GGA) calculations were used to study the adsorption of several atomic species, molecular species and molecular fragments on the Au(111) surface with a coverage of 1/4 monolayer (ML). Binding geometries, binding energies, and diffusion barriers were calculated for 27 species. Furthermore, we calculated the surface deformation energy associated with the binding events. The binding strength for all the analyzed species can be ordered as follows: NH3 < NO < CO < CH3 < HCO < NH2 < COOH < OH < HCOO < CNH2 < H < N < NH < NOH < COH < Cl,< HCO3 < CH2 < CN b HNO < O < F < S < C < CH. Although the atomic species preferred to bind at the three-fold fcc site, no tendency was observed in site preference for the molecular species and fragments. The intramolecular and adsorbate-surface vibrational frequencies were calculated for all the adsorbates on their most energetically stable adsorption site. Most of the theoretical binding energies and frequencies agreed with experimental values reported in the literature. In general, the values obtained with the PW91 functional are more accurate than RPBE in reproducing these experimental binding energies. The energies of the adsorbed species were used to calculate the thermochemical potential energy surfaces for decomposition of CO, NO, N2, NH3 and CH4, oxidation of CO, and hydrogenation of CO, CO2 and NO, giving insight into the thermochemistry of these reactions on gold nanoparticles. These potential energy surfaces demonstrated that: the decomposition of species is not energetically favorable on Au(111); the desorption of NH3, NO and CO are more favorable than their decomposition; the oxidation of CO and hydrogenation of CO and NO on Au(111) to form HCO and HNO, respectively, are also thermodynamically favorable.

  5. Photosynthetic electron transport system promotes synthesis of Au-nanoparticles.

    PubMed

    Shabnam, Nisha; Pardha-Saradhi, P

    2013-01-01

    In this communication, a novel, green, efficient and economically viable light mediated protocol for generation of Au-nanoparticles using most vital organelle, chloroplasts, of the plant system is portrayed. Thylakoids/chloroplasts isolated from Potamogeton nodosus (an aquatic plant) and Spinacia oleracea (a terrestrial plant) turned Au³⁺ solutions purple in presence of light of 600 µmol m⁻² s⁻¹ photon flux density (PFD) and the purple coloration intensified with time. UV-Vis spectra of these purple colored solutions showed absorption peak at ∼545 nm which is known to arise due to surface plasmon oscillations specific to Au-nanoparticles. However, thylakoids/chloroplasts did not alter color of Au³⁺ solutions in dark. These results clearly demonstrated that photosynthetic electron transport can reduce Au³⁺ to Au⁰ which nucleate to form Au-nanoparticles in presence of light. Transmission electron microscopic studies revealed that Au-nanoparticles generated by light driven photosynthetic electron transport system of thylakoids/chloroplasts were in range of 5-20 nm. Selected area electron diffraction and powder X-ray diffraction indicated crystalline nature of these nanoparticles. Energy dispersive X-ray confirmed that these nanoparticles were composed of Au. To confirm the potential of light driven photosynthetic electron transport in generation of Au-nanoparticles, thylakoids/chloroplasts were tested for their efficacy to generate Au-nanoparticles in presence of light of PFD ranging from 60 to 600 µmol m⁻² s⁻¹. The capacity of thylakoids/chloroplasts to generate Au-nanoparticles increased remarkably with increase in PFD, which further clearly demonstrated potential of light driven photosynthetic electron transport in reduction of Au³⁺ to Au⁰ to form nanoparticles. The light driven donation of electrons to metal ions by thylakoids/chloroplasts can be exploited for large scale production of nanoparticles. PMID:23976990

  6. African Regional Symposium on Telematics for Development. Report and Recommendations = Colloque regional africain la telematique au service du developpement. Rapport et recommandations (Addis Ababa, Ethiopia, April 3-7, 1995).

    ERIC Educational Resources Information Center

    International Telecommunication Union, Geneva (Switzerland).

    The African Regional Symposium on Telematics for Development was organized in view of the special educational and communication needs of Africa in a time of accelerating change and development of information technologies. The symposium brought together more than 150 African specialists, and over 40 participants from other regions and development…

  7. A Cappella: A Report on the Realities, Concerns, Expectations and Barriers Experienced by Adolescent Women in Canada = A Cappella: Rapport sur les realites, preoccupations, attentes et obstacles que connaissent les adolescentes au Canada.

    ERIC Educational Resources Information Center

    Canadian Teachers' Federation, Ottawa (Ontario).

    In the spring of 1990 a project was undertaken in Canada to document the major concerns and perceptions of adolescent women; to supplement the words of adolescent women with brief summaries of current knowledge; to use the words of adolescent women and the additional knowledge gathered to provide information to young women on issues which are of…

  8. Systematic studies of the centrality dependence of soft photon production in Au + Au collision with PHENIX

    NASA Astrophysics Data System (ADS)

    Bannier, Benjamin

    2014-11-01

    Since the earliest days of Heavy Ion Physics thermal soft photon radiation emitted during the reaction had been theorized as a smoking gun signal for formation of a quark-gluon plasma and as a tool to characterize its properties. In recent years the existence of excess photon radiation in heavy ion collisions over the expectation from initial hard interactions has been confirmed at both RHIC and LHC energies by PHENIX and ALICE respectively. There the radiation has been found to exhibit elliptic flow v2 well above what can currently be reconciled with a picture of early emission from a plasma phase. During the 2007 and 2010 Au + Au runs PHENIX has measured a high purity sample of soft photons down to pT > 0.4 GeV / c using an external conversion method. We present recent systematic studies by PHENIX from that sample on the centrality dependence of the soft photon yield, and elliptic and triangular flow v2 and v3 in Au + Au collisions which fill in the experimental picture and enable discrimination of competing soft photon production scenarios.

  9. Photoionization of Au+ ions and developments in the synthesis of the metallofullerene Au@C60

    NASA Astrophysics Data System (ADS)

    Bogolub, Kyren; Macaluso, David; Mueller, Allison; Johnson, Andrea; Müller, Alfred; Schippers, Stefan; Hellhund, Jonas; Borovik, Alexander; Anders, Andre; Aguilar, Alex; Kilcoyne, A. L. David

    2014-05-01

    Single photoionization of Au+ ions was investigated via the merged-beams technique at AMO Beamline 10.0.1.2 of the Advanced Light Source at Lawrence Berkeley National Laboratory. The relative single photoionization yield was measured as a function of photon energy in the 45 eV to 120 eV energy range. These measurements were made in preparation for future photoionization studies of the endohedral metallofullerene Au@C60, the production of which was also investigated. In proof-of-principle measurements a mass-resolved beam of Au@C60+was produced with a primary ion beam current in the single picoamp range without optimization of the ion source or synthesis parameters. Plans are presented for improved metallofullere production yield to be used in photoionization measurements of the endohedral fullerene ions in conjunction with the continuing study of pure Au. We would like to acknowledge the generous sharing of equipment vital to this work by Andre Anders, the Plasma Applications group leader at the Advanced Light Source, LBNL.

  10. Preparations for p-Au run in 2015

    SciTech Connect

    Liu, C.

    2014-12-31

    The p-Au particle collision is a unique category of collision runs. This is resulted from the different charge mass ratio of the proton and fully stripped Au ion (1 vs.79/197). The p-Au run requires a special acceleration ramp, and movement of a number of beam components as required by the beam trajectories. The DX magnets will be moved for the first time in the history of RHIC. In this note, the planning and preparations for p-Au run will be presented.

  11. An Exploration of Catalytic Chemistry on Au/Ni(111)

    SciTech Connect

    Sylvia T. Ceyer

    2011-12-09

    This project explored the catalytic oxidation chemistry that can be effected on a Au/Ni(111) surface alloy. A Au/Ni(111) surface alloy is a Ni(111) surface on which less than 60% of the Ni atoms are replaced at random positions by Au atoms. The alloy is produced by vapor deposition of a small amount of Au onto Ni single crystals. The Au atoms do not result in an epitaxial Au overlayer or in the condensation of the Au into droplets. Instead, Au atoms displace and then replace Ni atoms on a Ni(111) surface, even though Au is immiscible in bulk Ni. The two dimensional structure of the clean Ni surface is preserved. This alloy is found to stabilize an adsorbed peroxo-like O2 species that is shown to be the critical reactant in the low temperature catalytic oxidation of CO and that is suspected to be the critical reactant in other oxidation reactions. This investigation revealed a new, practically important catalyst for CO oxidation that has since been patented.

  12. Heatless synthesis of well dispersible Au nanoparticles using pectin biopolymer.

    PubMed

    Ahmed, Hanan B; Zahran, M K; Emam, Hossam E

    2016-10-01

    Due to its potency to utilize in enormous applications, preparation of nanogold is of interest. Moreover, getting of highly dispersed nanogold with small size is extremely needful in specific fields. Herein, Au nanocolloid was prepared using alkali catalyzed pectin biopolymer. Pectin was concurrently used as reductant for Au ions and stabilizer for the produced Au nanoparticles (AuNPs). Reducing sugars were evaluated in the colloidal solution reflecting the role alkali in catalytic degradation of pectin to produce much powerful reducing moieties. The obtained Au nanocolloid was monitored via changing in color, UV-visible spectral and transmission electron microscopy. Using of NaOH as strong alkali achieving rapid rate of degradation reaction, resulted in 0.45g/L reducing sugars from 0.2g/L pectin which produced AuNPs with mean size of 6.5nm. In case of Na2CO3 which attained slow degradation rate led to, slightly low reducing sugar content (0.41g/L), fabricated comparatively size of AuNPs (7.5nm). In both cases, well distributed AuNPs was obtained with suitable stabilization up to 5 months and Na2CO3 exhibited higher stability. The current successful method used to produce small sized AuNPs with high dispersion is an innovative, one-step, easily, costless, energy saving and eco-friendly method. PMID:27212212

  13. Local anodic oxidation patterning of Au deposited Si surfaces.

    PubMed

    Vijaykumar, T; Kulkarni, G U

    2009-09-01

    Nanopatterning of Si(100) surfaces deposited with Au films from physical and chemical methods, has been carried out using a AFM set up mounted with a conducting tip. At a tip bias of -12 V, the LAO patterns drawn on various Au/SiOx surfaces have been compared with those on bare Si. The height of the oxide patterns is several times higher in the case of Au covered Si surfaces compared to patterns on bare Si surface. The enhancement in LAO is related to the catalytic activity of Au nanoparticulates at SiOx interface. PMID:19928226

  14. Prolonged reorganization of thiol-capped Au nanoparticles layered structures

    NASA Astrophysics Data System (ADS)

    Kundu, Sarathi; Das, Kaushik; Konovalov, Oleg

    2013-09-01

    Prolonged reorganization behaviour of mono-, di-, tri- and multi-layer films of Au nanoparticles prepared by Langmuir-Blodgett method on hydrophobic Si(001) substrates have been studied by using X-ray scattering techniques. Out-of-plane study shows that although at the initial stage the reorganization occurs through the compaction of the films keeping the layered structure unchanged but finally all layered structures modify to monolayer structure. Due to this reorganization the Au density increases within the nanometer thick films. In-plane study shows that inside the reorganized films Au nanoparticles are distributed randomly and the particle size modifies as the metallic core of Au nanoparticles coalesces.

  15. Layer growth in Au-Pb/In solder joints

    SciTech Connect

    Yost, F.G.; Ganyard, F.P.; Karnowsky, M.M.

    1986-01-01

    The solid state reaction between a Pb-In solder alloy and thin film Au has been investigated at ten aging temperatures ranging from 70 to 170/sup 0/C. Also, bulk Au-solder samples were aged at 150/sup 0/C for metallographic analysis. No significant difference was found between the aging behavior of thin and bulk Au specimens. A thin single phase layer of Au/sub 9/In/sub 4/ was found adjacent to Au while a thick two-phase layer of AuIn/sub 2/ and Pb was found between Au/sub 9/In/sub 4/ and solder. The Pb phase was shown to have considerable mobility and able to ripen at room temperature. Peculiar planar interface instabilities and voids in the Au-Au/sub 9/In/sub 4/ interface were found. The total layer thickness was found to vary linearly with aging time, indicating an interface-controlled reaction. An activation energy of 14,000 calories per mole was found by regression analysis of the kinetic data.

  16. Do Methanethiol Adsorbates on the Au(111) Surface Dissociate?

    NASA Astrophysics Data System (ADS)

    Zhou, Jian-Ge; Hagelberg, Frank

    2006-07-01

    The interaction of methanethiol molecules CH3SH with the Au(111) surface is investigated, and it is found for the first time that the S-H bond remains intact when the methanethiol molecules are adsorbed on the regular Au(111) surface. However, it breaks if defects are present in the Au(111) surface. At low coverage, the fcc region is favored for S atom adsorption, but at saturated coverage the adsorption energies at various sites are almost isoenergetic. The presented calculations show that a methanethiol layer on the regular Au(111) surface does not dimerize.

  17. Density functional study of the cysteine adsorption on Au nanoclusters

    NASA Astrophysics Data System (ADS)

    Pérez, L. A.; López-Lozano, X.; Garzón, I. L.

    2009-04-01

    The adsorption of the cysteine amino acid (H-SCβH2-CαH-NH2-COOH) on the Au55 cluster is investigated through density functional theory calculations. Two isomers, with icosahedral (Ih) and chiral (C1) geometries, of the Au55 cluster are used to calculate the adsorption energy of the cysteine on different facets of these isomers. Results, only involving the S(thiolate)-Au bonding show that the higher adsorption energies are obtained when the sulfur atom is bonded to an asymmetrical bridge site at the facet containing Au atoms with the lowest coordination of the C1 cluster isomer.

  18. Electron paramagnetic resonance in positively charged Au25 molecular nanoclusters.

    PubMed

    Akbari-Sharbaf, Arash; Hesari, Mahdi; Workentin, Mark S; Fanchini, Giovanni

    2013-01-14

    In this study, we investigated the unpaired electrons and singly occupied molecular orbitals (SOMO) of positively charged Au(25) molecular clusters using solid-state electron paramagnetic resonance (EPR). The EPR powder spectra of the positively charged (Au(25) (+)) and neutral (Au(25) (0)) species of Au(25) are discussed and compared. Our study demonstrates that Au(25) (+) is paramagnetic with a SOMO that is mostly localized about the central gold atom in the core of the molecule and possesses a strong p-type atomic character. The unpaired electron spin is demonstrated to strongly interact with the nuclear spins from other (197)Au nuclei in the core of Au(25) (+) molecules and the hyperfine tensor describing such interaction was extracted from the comparison of the EPR spectra with quantum mechanical simulations assuming an anisotropic structure of the core. Our simulations suggest that the core of Au(25) (+) molecular clusters is more distorted than in the corresponding neutral counterpart. They also confirm previous hypotheses suggesting that the icosahedral core of Au(25) (+) experiences contraction with decreasing temperature. PMID:23320681

  19. Atomistic simulations of Au-silica nanocomposite film growth

    SciTech Connect

    Khan, Saif A.; Heinig, K.-H.; Avasthi, D. K.

    2011-05-01

    The growth of Au-silica nanocomposite film is simulated in the framework of kinetic three dimensional lattice Monte Carlo simulations considering the basic phenomena in the deposition process. In case of co-sputter deposition, the growth kinetics of nanoparticles has been studied taking into consideration the effect of the energetic sputtered species reaching the surface of the film during deposition. Formation of Au nanorod like structures are predicted under certain growth conditions particularly when surface diffusion assisted phase separation plays the dominant role and bulk kinetics is frozen. The observed dependence of the Au nanoparticle size on Au/silica ratio is in agreement with the experimental results.

  20. Enhanced photoluminescence in Au-embedded ITO nanowires.

    PubMed

    Kim, Hyunsu; Park, Sunghoon; Jin, Changhyun; Lee, Chongmu

    2011-12-01

    Gold (Au)-embedded indium tin oxide (ITO) nanowires were synthesized by thermal evaporation of a mixture of In(2)O(3,) SnO(2) and graphite powders on Si (100) substrates coated with Au thin films followed by annealing. At the initial stages of annealing, Au formed a continuous linear core located along the long axis of each ITO nanowire. The morphology of the Au core changed from a continuous line to a discrete line, and then to a droplet-like chain, finally evolving into a peapod in which crystalline Au nanoparticles were encapsulated in crystalline ITO with increasing annealing temperature. The ITO nanowires with the Au core showed an emission band at ~380 nm in the ultraviolet region. The ultraviolet emission intensity increased rapidly with increasing annealing temperature. The intensity of emission from the Au-peapod ITO nanowires (annealed at 750 °C) was approximately 20 times higher than that of the emission from the Au-core/ITO-shell ITO nanowires with a continuous linear shaped-Au core (annealed at 550 °C). This ultraintense ultraviolet emission might have originated mainly from the enhanced crystalline quality of the annealed ITO nanowires. PMID:22087582

  1. Analyse sérologique de la toxoplasmose pergravidique: évaluation des risques et perspectives du dépistage prénatal au centre hospitalier universitaire de Bobo Dioulasso au Burkina Faso

    PubMed Central

    Bamba, Sanata; Some, Der Adolphe; Chemla, Cathy; Geers, Régine; Guiguemde, Tinga Robert; Villena, Isabelle

    2012-01-01

    Introduction La présente étude rapporte les données sérologiques de 306 sérums collectés chez des parturientes au CHU de Bobo Dioulasso et analysés rétrospectivement au CHU de Reims en 2011. Le but était de déterminer le statut sérologique de ces parturientes et d'en déduire la conduite à tenir. Méthodes La recherche des IgG et des IgM anti toxoplasmiques était systématique. Les techniques d'agglutination haute sensibilisée et celle d'Immunocapture M ont servi à la recherche respective des anticorps spécifiques IgG et des IgM. Résultats Sur 306 sérums analysés, 95 (31%) avaient des IgG positifs et aucun n'avait des IgM. Deux cent onze (211) sérums (69%) des sérums n'avaient ni IgG, ni IgM. Conclusion Nos résultats montrent que 31% des femmes en dehors d'une immunodépression sous jacente, possèdent une immunité résiduelle vis à vis de Toxoplasma gondii et n'ont pas la nécessité d'avoir une surveillance sérologique pendant la grossesse. Cependant, 69% (211) des parturientes sont à risque d'une séroconversion, et devraient bénéficier de conseils hygiéno diététiques, associés à une surveillance sérologique durant la grossesse. Ces résultats montrent l'intérêt de mettre en place des mesures de prévention contre la toxoplasmose congénitale, étant l'une des affections materno - foetales les plus fréquentes par la mise en place d'un diagnostic prénatal de la toxoplasmose en routine dans notre hôpital. PMID:22937183

  2. Component conversion from pure Au nanorods to multiblock Ag-Au-Ag nanorods assisted by Pt nanoframe templates.

    PubMed

    Lee, Sangji; Jang, Hee-Jeong; Jang, Ho Young; Kim, Seong Kyu; Park, Sungho

    2016-07-14

    We developed a new method for synthesizing multiblock Ag-Au-Ag nanorods using Pt nanoframes that had been deposited on the edges of Au nanorod seeds. As a function of Au etching time, the length of the Au nanorod decreased symmetrically starting from the two ends, leading to the formation of empty inner space at the ends. Subsequent reduction of Ag ions could be selectively performed in the inner space confined by Pt nanoframes and the resulting Ag-Au-Ag nanorods exhibited characteristic LSPR modes originating from each block component (in a transverse direction) and SPR coupling (in a longitudinal direction). The high quality of the resulting multiblock nanorods enabled observation of the longitudinal quadrupole mode that was induced by Ag-Au SPR coupling in a long axis. The mode exhibited high sensitivity in accordance with the change in the surrounding media, demonstrating great potential for sensor applications. PMID:27315144

  3. Diffusion of the Linear CH3S-Au-SCH3 Complex on Au(111) from First Principles

    SciTech Connect

    Jiang, Deen; Dai, Sheng

    2009-01-01

    Recent experimental and computational advances have clearly established the importance of the linear alkylthiolate-Au-alkylthiolate (RS-Au-SR) complex at the interface between the thiolate groups and the gold surface. By using density functional theory-based first principles method, here we show that the elementary diffusion step of this linear complex on Au(111) has a barrier of only {approx}0.5 eV in the case of methylthiolate, indicating great mobility of the linear complex on Au(111). The role of this low barrier in the formation of a self-assembled monolayer of thiolate groups in the form of RS-Au-SR on Au(111) is discussed.

  4. Observation of D0 Meson Nuclear Modifications in Au +Au Collisions at √sNN =200 GeV

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; Dhamija, S.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Finch, E.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; LeVine, M. J.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Madagodagettige Don, D. M. M. D.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Pachr, M.; Page, B. S.; Pal, S. K.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Peryt, W.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Pujahari, P. R.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Singaraju, R. N.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zawisza, Y.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2014-10-01

    We report the first measurement of charmed-hadron (D0) production via the hadronic decay channel (D0→K-+π+) in Au +Au collisions at √sNN =200 GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, Nbin, from p +p to central Au +Au collisions. The D0 meson yields in central Au +Au collisions are strongly suppressed compared to those in p+p scaled by Nbin, for transverse momenta pT>3 GeV /c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate pT is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.

  5. Heterostructured Au/Pd-M (M = Au, Pd, Pt) nanoparticles with compartmentalized composition, morphology, and electrocatalytic activity.

    PubMed

    Lutz, Patrick S; Bae, In-Tae; Maye, Mathew M

    2015-10-14

    The synthesis, processing, and galvanic exchange of three heterostructured nanoparticle systems is described. The surface accessibility and redox potential of a Au/Pd-Ag dumbbell nanoparticle, where a Au/Pd core/shell region, and a silver region make up the domains, was used to prepare the new nanostructures with controlled composition, morphology, and microstructure. Results indicate that the silver domain was particularly susceptible to galvanic displacement, and was exchanged to Au/Pd-M (M = Au, Pd, Pt). Interestingly, the dumbbell morphology remained after exchange, and the silver region was transformed to hollow, parachute, or concentric domains respectively. The morphology and microstructure change was visualized via TEM and HRTEM, and the composition changes were probed via STEM-EDS imaging and XPS. The electrocatalytic activity of the Au/Pd-M towards methanol oxidation was studied, with results indicating that the Au/Pd-Pt nanoparticles had high activity attributed to the porous nature of the platinum domains. PMID:26351824

  6. Component conversion from pure Au nanorods to multiblock Ag-Au-Ag nanorods assisted by Pt nanoframe templates

    NASA Astrophysics Data System (ADS)

    Lee, Sangji; Jang, Hee-Jeong; Jang, Ho Young; Kim, Seong Kyu; Park, Sungho

    2016-06-01

    We developed a new method for synthesizing multiblock Ag-Au-Ag nanorods using Pt nanoframes that had been deposited on the edges of Au nanorod seeds. As a function of Au etching time, the length of the Au nanorod decreased symmetrically starting from the two ends, leading to the formation of empty inner space at the ends. Subsequent reduction of Ag ions could be selectively performed in the inner space confined by Pt nanoframes and the resulting Ag-Au-Ag nanorods exhibited characteristic LSPR modes originating from each block component (in a transverse direction) and SPR coupling (in a longitudinal direction). The high quality of the resulting multiblock nanorods enabled observation of the longitudinal quadrupole mode that was induced by Ag-Au SPR coupling in a long axis. The mode exhibited high sensitivity in accordance with the change in the surrounding media, demonstrating great potential for sensor applications.We developed a new method for synthesizing multiblock Ag-Au-Ag nanorods using Pt nanoframes that had been deposited on the edges of Au nanorod seeds. As a function of Au etching time, the length of the Au nanorod decreased symmetrically starting from the two ends, leading to the formation of empty inner space at the ends. Subsequent reduction of Ag ions could be selectively performed in the inner space confined by Pt nanoframes and the resulting Ag-Au-Ag nanorods exhibited characteristic LSPR modes originating from each block component (in a transverse direction) and SPR coupling (in a longitudinal direction). The high quality of the resulting multiblock nanorods enabled observation of the longitudinal quadrupole mode that was induced by Ag-Au SPR coupling in a long axis. The mode exhibited high sensitivity in accordance with the change in the surrounding media, demonstrating great potential for sensor applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr03484e

  7. Mesomorphic lamella rolling of au in vacuum.

    PubMed

    Huang, Chang-Ning; Chen, Shuei-Yuan; Shen, Pouyan

    2009-01-01

    Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241-0.192 nm) and the nearest neighbor distance (ca. 0.74-0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458-0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon-hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration. PMID:20628452

  8. Interplanetary magnetic clouds at 1 AU

    NASA Technical Reports Server (NTRS)

    Klein, L. W.; Burlaga, L. F.

    1981-01-01

    Magnetic clouds are defined as regions with a radial dimension approximately 0.25 AU (at 1 AU) in which the magnetic field strength is high and the magnetic field direction changes appreciably by means of rotation of one component of B nearly parallel to a plane. The magnetic field geometry in such a magnetic cloud is consistent with that of a magnetic loop, but it cannot be determined uniquely. Forty-five clouds were identified in interplanetary data obtained near Earth between 1967 and 1978; at least one cloud passed the Earth every three months. Three classes of clouds were identified, corresponding to the association of a cloud with a shock, a stream interface, or a CME. There are approximately equal numbers of clouds in each class, and the three types of clouds might be different manifestations of a coronal transient. The magnetic pressure inside the clouds is higher than the ion pressure and the sum is higher than the pressure of the material outside of the cloud.

  9. Mesomorphic Lamella Rolling of Au in Vacuum

    NASA Astrophysics Data System (ADS)

    Huang, Chang-Ning; Chen, Shuei-Yuan; Shen, Pouyan

    2009-11-01

    Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241-0.192 nm) and the nearest neighbor distance (ca. 0.74-0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458-0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon-hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration.

  10. Mesomorphic Lamella Rolling of Au in Vacuum

    PubMed Central

    2009-01-01

    Lamellar nanocondensates in partial epitaxy with larger-sized multiply twinned particles (MTPs) or alternatively in the form of multiple-walled tubes (MWTs) having nothing to do with MTP were produced by the very energetic pulse laser ablation of Au target in vacuum under specified power density and pulses. Transmission electron microscopic observations revealed (111)-motif diffraction and low-angle scattering. They correspond to layer interspacing (0.241–0.192 nm) and the nearest neighbor distance (ca. 0.74–0.55 nm) of atom clusters within the layer, respectively, for the lamella, which shows interspacing contraction with decreasing particle size under the influence of surface stress and rolls up upon electron irradiation. The uncapped MWT has nearly concentric amorphous layers interspaced by 0.458–0.335 nm depending on dislocation distribution and becomes spherical onions for surface-area reduction upon electron dosage. Analogous to graphene-derived tubular materials, the lamella-derived MWT of Au could have pentagon–hexagon pair at its zig-zag junction and useful optoelectronic properties worthy of exploration. PMID:20628452

  11. Ordered arrays of Au catalysts by FIB assisted heterogeneous dewetting

    NASA Astrophysics Data System (ADS)

    Benkouider, A.; Ronda, A.; David, T.; Favre, L.; Abbarchi, M.; Naffouti, M.; Osmond, J.; Delobbe, A.; Sudraud, P.; Berbezier, I.

    2015-12-01

    Synthesizing Au0.8Si0.2 nanocatalysts that are homogeneous in size and have controlled position is becoming a challenging and crucial prequisite for the fabrication of ordered semiconductor nanowires. In this study, Au0.8Si0.2 nanocatalysts are synthesized via dewetting of Au layers on Si(111) during thermal annealing in an ultra-high vacuum. In the first part of the paper, the mechanism of homogeneous dewetting is analyzed as a function of the Au-deposited thickness (h Au). We distinguish three different dewetting regimes: (I) for a low thickness ({h}{{Au}}≤slant 0.4 {nm}), a submonolyer coverage of Au is stabilized and there is no dewetting. (II) For an intermediate thickness (0.4 {nm}\\lt {h}{Au}≤slant 5 {nm}), there is both dewetting and Au0.8Si0.2 phase formation. The size and density of the Au0.8Si0.2 clusters are directly related to h Au. When cooling down to room temperature, the clusters decompose and reject the Si at the Au/Si substrate interface. (III) For a large thickness ({h}{{Au}}\\gt 5 {nm}), only dewetting takes place, without forming AuSi clusters. In this regime, the dewetting is kinetically controlled by the self-diffusion of Au (activation energy ∼0.43 eV) without evidence of an Si-alloying effect. As a practical consequence, when relying solely on the homogeneous dewetting of Au/Si(111) to form the Au0.8Si0.2 catalysts (without a supply of Si atoms from vapor), regime II should be used to obtain good size and density control. In the second part of the paper, a process for ordering the catalysts using focused ion beam-(FIB) assisted dewetting (heterogeneous dewetting) is developed. We show that no matter what the FIB milling conditions and the Au nominal thickness are, dewetting is promoted by ion beam irradiation and is accompanied by the formation of Au0.8Si0.2 droplets. The droplets preferentially form on the patterned areas, while in similar annealing conditions, they do not form on the unpatterned areas. This behavior is attributed

  12. Coating of a layer of Au on Al13 : The findings of icosahedral Al@Al12Au20- and Al12Au202- fullerenes using ab initio pseudopotential calculations

    NASA Astrophysics Data System (ADS)

    Kumar, Vijay

    2009-02-01

    We report results of ab initio pseudopotential calculations on the nanocoating of gold on an icosahedral Al13 cluster and the findings of icosahedrally symmetric endohedral Al@Al12Au20- and empty cage Al12Au202- compound fullerenes formed of metal atoms. Twelve Al atoms cap the pentagonal faces of a dodecahedral Au20 cage in which each Au atom has three Al atoms and three Au atoms as nearest neighbors. Mixing of Al13 and Au20 magic clusters leads to a large heat of formation of 0.55 eV/atom and high stability of the Al@Al12Au20 compound fullerene. The binding energies of Al12Au20 and Al@Al12Au20 are 3.017 and 3.007 eV/atom, respectively, which are much larger than 2.457 eV/atom for Au32 fullerene, leading to the possibility of their high abundance.

  13. Facile synthesis of ultrathin Au nanorods by aging the AuCl(oleylamine) complex with amorphous Fe nanoparticles in chloroform.

    PubMed

    Li, Zhengquan; Tao, Jing; Lu, Xianmao; Zhu, Yimei; Xia, Younan

    2008-09-01

    Despite plenty of reports on the preparation of Au nanorods, it remains challenging to grow uniform Au nanorods with diameters below 5 nm. In this communication, we demonstrate the facile synthesis of ultrathin Au nanorods with a uniform diameter of 2 nm and an average aspect ratio of 30. The synthesis involves the room-temperature aging of a mixture of the [AuCl(oleylamine)] complex with amorphous Fe nanoparticles in chloroform. Analysis of the growth mechanism indicates that Au nanoparticles with a high density of defects were formed at early stages, followed by etching and redeposition process that gradually led to the growth of ultrathin Au nanorods along the 111 direction. This growth mechanism is different from the mechanism recently reported for ultrathin Au nanowires (ref ), where the [AuCl(oleylamine)] complex is assembled into polymer chains followed by reduction to form wires, although the template effect of oleylamine for the formation of ultrathin Au nanorods cannot be completely ruled out. PMID:18681484

  14. Gold Apes Hydrogen. The Structure and Bonding in the Planar B7Au2- and B7Au2 Clusters

    SciTech Connect

    Zhai, Hua JIN.; Wang, Lai S.; Zubarev, Dmitry Y.; Boldyrev, Alexander I.

    2006-02-09

    We produced the B7Au2- mixed cluster and studied its electronic structure and chemical bonding using photoelectron spectroscopy and ab initio calculations. The photoelectron spectra of B7Au2- were observed to be relatively simple with vibrational resolution, in contrast to the complicated spectra observed for pure B7-, which had contributions from three isomers (Alexandrova et al., J. Phys. Chem. A, 2004, 108, 3509). Theoretical calculations show that B7Au2- possesses an extremely stable planar structure, identical to that of B7H2-, demonstrating that Au mimics H in its bonding to boron, analogous to the Au-Si bonding. The ground state structure of B7Au2- (B7H2-) can be viewed as adding two Au (H) atoms to the terminal B atoms of a higher-lying planar isomer of B7-. The bonding and stability in the planar B7Au2- (B7H2-) clusters are elucidated on the basis of the strong covalent B-Au (H) bonding and the concepts of aromaticity/antiaromaticity in these systems.

  15. Ultrafast charge carrier dynamics in Au/semiconductor nanoheterostructures

    NASA Astrophysics Data System (ADS)

    Lambright, Scott

    The charge carrier dynamics in several Au/semiconductor core/shell heterostructures were examined. Firstly, Au/CdS core/shell nanocomposites were synthesized in a four step procedure culminating in a cation exchange performed on the shell. Previous studies of the ultrafast carrier dynamics in Au/CdS nanocomposites with epitaxial boundary regions reported the suppression of plasmon character in transient absorption spectra accompanied by broadband photoinduced absorption. The coupling of electron wavefunctions with lattice defects at the boundary of the two domains has been blamed for these phenomena. In the current study, transmission electron micrographs of Au/CdS synthesized using cation exchange showed no evidence of strain on the lattice of either component, while femtosecond transient absorption data show the retention of bleach regions attributed to CdS's 1S(e)-1S3/2(h) transition and Au's plasmon resonance. Accelerated rates of bleach recovery for both excitations ( tauexiton ≈ 300 ps, tauplasmon ≈ .7 ps) indicated that the interaction of Au and CdS domains leads to faster relaxation to their respective photoexcitations when compared to relaxation times in isolated Au and CdS nanoparticles. It was believed that the Au/CdS boundary was non-epitaxial in the presented core/shell nanocomposites. Secondly, these non-epitaxial Au/CdS core/shells were subsequently used to demonstrate near-field energy transfer from 5 nm diameter Au cores to CdS-encapsulated CdSe quantum dots. To this end, Au/CdS and CdSe/CdS nanocrystals were embedded in semiconductor-matrix-encapsulated-nanocrystal-arrays (SMENA) together. The encapsulation of both domains in the high band-gap semiconductor CdS was a means to suppress charge transfer between the two nanoparticles. The fluorescence intensity in these films was enhanced 6-fold in some cases as a result of the presence of Au domains. It was also demonstrated that the fluorescence enhancement was independent of the potential

  16. Gas phase selective hydrogenation over oxide supported Ni-Au.

    PubMed

    Cárdenas-Lizana, Fernando; Keane, Mark A

    2015-11-14

    The chemoselective continuous gas phase (T = 573 K; P = 1 atm) hydrogenation of nitroarenes (p-chloronitrobenzene (p-CNB) and m-dinitrobenzene (m-DNB)) has been investigated over a series of oxide (Al2O3 and TiO2) supported Au and Ni-Au (1 : 10 mol ratio; 0.1-1 mol% Au) catalysts. Monometallic supported Au with mean particle size 3-9 nm promoted exclusive formation of p-chloroaniline (p-CAN) and m-nitroaniline (m-NAN). Selective hydrogenation rate was higher over smaller Au particles and can be attributed to increased surface hydrogen (from TPD measurements) at higher metal dispersion. (S)TEM analysis has confirmed an equivalent metal particle size for the supported bimetallics at the same Au loading where TPR indicates Ni-Au interaction and EDX surface mapping established Ni in close proximity to Au on isolated nanoparticles with a composition (Au/Ni) close to the bulk value (= 10). Increased spillover hydrogen due to the incorporation of Ni in the bimetallics resulted in elevated -NO2 group reduction rate. Full selectivity to p-CAN was maintained over all the bimetallic catalysts. Conversion of m-DNB over the lower loaded Ni-Au/Al2O3 generated m-NAN as sole product. An increase in Ni content (0.01 → 0.1 mol%) or a switch from Al2O3 to TiO2 as support resulted in full -NO2 reduction (to m-phenylenediamine). Our results demonstrate the viability of Ni-promotion of Au in the continuous production of functionalised anilines. PMID:25752655

  17. CO oxidation on h-BN supported Au atom

    SciTech Connect

    Gao Min; Lyalin, Andrey; Taketsugu, Tetsuya

    2013-01-21

    The mechanism of CO oxidation by O{sub 2} on Au atoms supported on the pristine and defected hexagonal boron nitride (h-BN) surface has been studied theoretically using density functional theory. It is found that O{sub 2} binds stronger than CO on an Au atom supported on the defect free h-BN surface and h-BN surface with nitrogen vacancy (V{sub N}-h-BN), but weaker than CO on a free Au atom or Au trapped by a boron vacancy (V{sub B}-h-BN). The excess of the positive or negative charge on Au can considerably change its catalytic properties and enhance activation of the adsorbed O{sub 2}. Coadsorption of CO and O{sub 2} on Au, Au/V{sub N}-h-BN, and Au/V{sub B}-h-BN results in additional charge transfer to O{sub 2}. Various pathways of the CO oxidation reaction by molecular oxygen are studied. We found two different pathways for CO oxidation: a two-step pathway where two CO{sub 2} molecules are formed independently, and a self-promotion pathway where oxidation of the first CO molecule is promoted by the second CO molecule. Interaction of Au with the defect-free and defected h-BN surface considerably affects the CO oxidation reaction pathways and barriers. Therefore, Au supported on the h-BN surface (pristine or defected) cannot be considered as pseudo-free atom and support effects have to be taken into account, even when the interaction of Au with the support is weak.

  18. Mixed Valent Gold Oxides: Syntheses, Structures, and Properties of Rb 5Au 3O 2, Rb 7Au 5O 2, and Cs 7Au 5O 2

    NASA Astrophysics Data System (ADS)

    Mudring, Anja-Verena; Nuss, Jürgen; Wedig, Ulrich; Jansen, Martin

    2000-11-01

    The title compounds Rb5Au3O2, Rb7Au5O2, and Cs7Au5O2 are the first examples of mixed valent phases containing gold in the oxidation states +1 and -1. Their crystal structures (Rb5Au3O2, Pbam, a=736.4(1) pm, b=1430.8(2) pm, c=567.9(1) pm, Z=2, R(F)=0.053, 647 reflections; Rb7Au5O2, Immm, a=567.1(2) pm, b=930.1(1) pm, C=1659.4(3) pm, Z=2, R(F)=0.066, 409 reflections; Cs7Au5O2, Immm, a=599.4(1) pm, b=960.6(3) pm, c=1720.8(12) pm, Z=2, R(F)=0.039, 386 reflections) are characterized by the combination of distinctive structural features of gold(I) oxides and aurides: for Au(+1) a typical linear coordination by oxygen is found and the surroundings of Au(-1) bear a close resemblance to the binary 1:1 aurides. In consequence the overall structures of Rb5Au3O2 and M7Au5O2 can be described as intergrowths of M3AuO2 and MAu (M=Rb, Cs), constituting members of a homologous series [MAu]n[M3AuO2] with n=2 and 4, respectively. The crystal chemical evidence for the valence states assumed, also confirmed by Mößbauer spectroscopy, is supported by various band structure calculations (Hartee-Fock and density functional) clearly indicating the coexistence of two different oxidation states. The compounds have been synthesized by reacting binary aurides MAu and alkali monoxides M2O (M=Rb, Cs) with elemental gold in the required stochiometric amounts. Hereby, a further astonishing parallel to the chemistry of halogens is revealed. Like these, gold disproportionates upon interaction with bases.

  19. High transverse momentum {eta} meson production in p+p,d+Au, and Au+Au collisions at {radical}(s{sub NN})=200 GeV

    SciTech Connect

    Adler, S. S.; Aronson, S. H.; Chujo, T.; David, G.; Desmond, E. J.; Drees, K. A.; Ewell, L.; Franz, A.; Guryn, W.; Haggerty, J. S.; Harvey, M.; Johnson, B. M.; Kistenev, E.; Kroon, P. J.; Makdisi, Y. I.; Mioduszewski, S.; Mitchell, J. T.; Morrison, D. P.; O'Brien, E.; Pinkenburg, C.

    2007-02-15

    Inclusive transverse momentum spectra of {eta} mesons in the range p{sub T}{approx_equal}2-12 GeV/c have been measured at midrapidity (|{eta}|<0.35) by the PHENIX experiment at RHIC in p+p,d+Au, and Au+Au collisions at {radical}(s{sub NN})=200 GeV. The {eta} mesons are reconstructed through their {eta}{yields}{gamma} {gamma} channel for the three colliding systems as well as through the {eta}{yields}{pi}{sup 0}{pi}{sup +}{pi}{sup -} decay mode in p+p and d+Au collisions. The nuclear modification factor in d+Au collisions, R{sub dAu}(p{sub T}){approx_equal}1.0-1.1, suggests at most only modest p{sub T} broadening (''Cronin enhancement''). In central Au+Au reactions, the {eta} yields are significantly suppressed, with R{sub AuAu}(p{sub T}){approx_equal}0.2. The ratio of {eta} to {pi}{sup 0} yields is approximately constant as a function of p{sub T} for the three colliding systems in agreement with the high-p{sub T} world average of R{sub {eta}/{pi}{sup 0}}{approx_equal}0.5 in hadron-hadron, hadron-nucleus, and nucleus-nucleus collisions for a wide range of center-of-mass energies ({radical}(s{sub NN}){approx_equal}3-1800 GeV) as well as, for high scaled momentum x{sub p}, in e{sup +}e{sup -} annihilations at {radical}(s)=91.2 GeV. These results are consistent with a scenario where high-p{sub T} {eta} production in nuclear collisions at the Relativistic Heavy Ion Collider is largely unaffected by initial-state effects but where light-quark mesons ({pi}{sup 0},{eta}) are equally suppressed due to final-state interactions of the parent partons in the dense medium produced in Au+Au reactions.

  20. Silver migration between Au38(SC2H4Ph)24 and doped AgxAu38-x(SC2H4Ph)24 nanoclusters.

    PubMed

    Zhang, Bei; Salassa, Giovanni; Bürgi, Thomas

    2016-07-28

    A fast redistribution of metal atoms occurs upon mixing the AgxAu38-x and Au38 nanoclusters in solution, as observed by mass spectrometry. Physical separation of AgxAu38-x and Au38 species by a dialysis membrane prohibits the metal migration, which suggests that collisions between the reacting clusters are at the origin of the observation. PMID:27352728

  1. Registration of ‘AU-1101’ peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    AU-1101’ (Reg. No. CV-xxx, PI 661498) is a large-seeded virginia-type peanut (Arachis hypogaea L. subsp. hypogaea var. hypogaea) with high yield and medium maturity, uniform pod size and shape, high grade, superior shelling characters, low oil content, normal oleic acid content, and good flavor. AU-...

  2. Deposition of Au and Ag nanoparticles on PEDOT.

    PubMed

    Danieli, Tamar; Colleran, John; Mandler, Daniel

    2011-12-01

    The deposition of Au and Ag, locally and from bulk solution, on poly(3,4-ethylenedioxythiophene) (PEDOT) was studied. Specifically, PEDOT was electrochemically polymerized onto a glassy carbon (GC) electrode and used for bulk deposition of Au and Ag from their respective ions dissolved in the solution as well as for the local deposition of these metals using scanning electrochemical microscopy (SECM). These two sets of experiments were utilized to investigate the difference between Au and Ag electrochemical deposition on PEDOT. In particular, SECM experiments, which were conducted by the controlled anodic dissolution of Au and Ag microelectrodes close to GC/PEDOT, probed the effect of different PEDOT oxidation states on local deposition. The current-time transients recorded during the deposition, combined with scanning electron microscopy and EDX analysis provided insight into the reduction processes. AuCl(4)(-) and Ag(+) ions were electrochemically reduced at a potential equal to and more negative than the ions redox potentials (0.4 and 0.2 V, respectively) and more positive than -0.7 V, where the PEDOT starts transforming into the reduced, i.e. insulating, state. We found that the electroreduction of Ag(+) ions was diffusion-controlled and the PEDOT film served as a simple conductor. On the other hand, the reduction of AuCl(4)(-) ions was enhanced on GC/PEDOT as compared with bare GC, indicating that PEDOT catalyzes the reduction of AuCl(4)(-) to Au. PMID:21993698

  3. Microstructural evolution of eutectic Au-Sn solder joints

    SciTech Connect

    Song, Ho Geon

    2002-05-31

    Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

  4. Formation of Cu x Au1- x phases by cold homogenization of Au/Cu nanocrystalline thin films.

    PubMed

    Tynkova, Alona; Katona, Gabor L; Langer, Gabor A; Sidorenko, Sergey I; Voloshko, Svetlana M; Beke, Dezso L

    2014-01-01

    It is shown, by using depth profiling with a secondary neutral mass spectrometer and structure investigations by XRD and TEM, that at low temperatures, at which the bulk diffusion is frozen, a complete homogenization can take place in the Cu/Au thin film system, which leads to formation of intermetallic phases. Different compounds can be formed depending on the initial thickness ratio. The process starts with grain boundary interdiffusion, which is followed by a formation of reaction layers at the grain boundaries that leads to the motion of the newly formed interfaces perpendicular to the grain boundary plane. Finally, the homogenization finishes when all the pure components have been consumed. The process is asymmetric: It is faster in the Au layer. In Au(25nm)/Cu(50nm) samples the final state is the ordered AuCu3 phase. Decrease of the film thicknesses, as expected, results in the acceleration of the process. It is also illustrated that changing the thickness ratio either a mixture of Cu-rich AuCu and AuCu3 phases (in Au(25nm)/Cu(25nm) sample), or a mixture of disordered Cu- as well as Au-rich solid solutions (in Au(25nm)/Cu(12nm) sample) can be produced. By using a simple model the interface velocity in both the Cu and Au layers were estimated from the linear increase of the average composition and its value is about two orders of magnitude larger in Au (ca. 10(-11) m/s) than in Cu (ca. 10(-13) m/s). PMID:25247132

  5. Formation of CuxAu1− x phases by cold homogenization of Au/Cu nanocrystalline thin films

    PubMed Central

    Tynkova, Alona; Katona, Gabor L; Langer, Gabor A; Sidorenko, Sergey I; Voloshko, Svetlana M

    2014-01-01

    Summary It is shown, by using depth profiling with a secondary neutral mass spectrometer and structure investigations by XRD and TEM, that at low temperatures, at which the bulk diffusion is frozen, a complete homogenization can take place in the Cu/Au thin film system, which leads to formation of intermetallic phases. Different compounds can be formed depending on the initial thickness ratio. The process starts with grain boundary interdiffusion, which is followed by a formation of reaction layers at the grain boundaries that leads to the motion of the newly formed interfaces perpendicular to the grain boundary plane. Finally, the homogenization finishes when all the pure components have been consumed. The process is asymmetric: It is faster in the Au layer. In Au(25nm)/Cu(50nm) samples the final state is the ordered AuCu3 phase. Decrease of the film thicknesses, as expected, results in the acceleration of the process. It is also illustrated that changing the thickness ratio either a mixture of Cu-rich AuCu and AuCu3 phases (in Au(25nm)/Cu(25nm) sample), or a mixture of disordered Cu- as well as Au-rich solid solutions (in Au(25nm)/Cu(12nm) sample) can be produced. By using a simple model the interface velocity in both the Cu and Au layers were estimated from the linear increase of the average composition and its value is about two orders of magnitude larger in Au (ca. 10−11 m/s) than in Cu (ca. 10−13 m/s). PMID:25247132

  6. Identification of Au–S complexes on Au(100)

    DOE PAGESBeta

    Walen, Holly; Liu, Da -Jiang; Oh, Junepyo; Yang, Hyun Jin; Kim, Yousoo; Thiel, P. A.

    2016-01-25

    In this study, using a combination of scanning tunneling microscopy and density functional theory (DFT) calculations, we have identified a set of related Au–S complexes that form on Au(100), when sulfur adsorbs and lifts the hexagonal surface reconstruction. The predominant complex is diamond-shaped with stoichiometry Au4S5. All of the complexes can be regarded as combinations of S–Au–S subunits. The complexes exist within, or at the edges of, p(2 × 2) sulfur islands that cover the unreconstructed Au regions, and are observed throughout the range of S coverage examined in this study, 0.009 to 0.12 monolayers. A qualitative model is developedmore » which incorporates competitive formation of complexes, Au rafts, and p(2 × 2) sulfur islands, as Au atoms are released by the surface structure transformation.« less

  7. High-spin level scheme of {sup 183}Au

    SciTech Connect

    Song, L.T.; Zhou, X.H.; Zhang, Y. H.; Guo, Y. X.; Lei, X.G.; Zheng, Y.; Liu, M.L.; De Angelis, G.; Marginean, N.; Gadea, A.; Napoli, D.R.; Axiotis, M.; Rusu, C.; Martinez, T.

    2005-01-01

    High-spin states in {sup 183}Au have been studied experimentally using the {sup 159}Tb({sup 29}Si,5n){sup 183}Au reaction at a beam energy of 140 MeV. Three- or higherfold {gamma}-ray coincidences have been measured using the detector array of GASP. The level scheme of {sup 183}Au was revised and extended. A rotational band proposed as the unfavored signature branch of the {pi}i{sub 13/2} band has been observed for {sup 183}Au. Interaction properties between the two negative-signature bands of the {pi}h{sub 9/2}-{pi}f{sub 7/2} system have been discussed for the light odd-A Au nuclei.

  8. Sputtering of Au induced by single Xe ion impacts

    SciTech Connect

    Birtcher, R. C.; Donnelly, S. E.

    1999-12-06

    Sputtering of Au thin films has been determined for Xe ions with energies between 50 and 600 keV. In-situ transmission electron microscopy was used to observe sputtered Au during deposition on a carbon foil near the specimen. Total reflection and transmission sputtering yields for a 62 nm thick Au thin film were determined by ex-situ measurement of the total amount of Au on the carbon foils. In situ observations show that individual Xe ions eject Au nanoparticles as large as 7 nm in diameter with an average diameter of approximately 3 nm. Particle emission correlates with crater formation due to single ion impacts. Nanoparticle emission contributes significantly to the total sputtering yield for Xe ions in this energy range in either reflection or transmission geometry.

  9. Graphene quantum dots/Au hybrid nanoparticles as electrocatalyst for hydrogen evolution reaction

    NASA Astrophysics Data System (ADS)

    Luo, Peihui; Jiang, Linqin; Zhang, Weilong; Guan, Xiangfeng

    2015-11-01

    Graphene quantum dots/Au hybrid nanoparticles (denoted as GQDs-Au) were prepared by heating HAuCl4 with GQDs, and they showed higher electrocatalytic activity for hydrogen evolution reaction than that of pure Au nanoparticles.

  10. The AuScope VLBI Array

    NASA Astrophysics Data System (ADS)

    Lovell, J.; McCallum, J.; Shabala, S.; Dickey, J.; Watson, C.; Titov, O.

    2012-12-01

    The AuScope VLBI array, consisting of three new 12-meter radio telescopes in Australia dedicated to geodesy, has recently commenced operations. The telescopes at Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western Australia) are co-located with other space geodetic techniques including Global Navigation Satellite Systems (GNSS) and gravity infrastructure, and in the case of Yarragadee, Satellite Laser Ranging facilities. This new facility will make significant contributions to improving the densification of the International Celestial Reference Frame in the southern hemisphere, and subsequently, improve the International Terrestrial Reference Frame through the improved ability to detect and mitigate systematic error. Improvements to both the ICRF and ITRF, as well as the simultaneous densification of the GNSS network across Australia will enable the improved measurement of intraplate deformation across the Australian tectonic plate.

  11. Azimuthal Anisotropy in U +U and Au +Au Collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandin, A. V.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cervantes, M. C.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, H. Z.; Huang, B.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Kosarzewski, L. K.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, W.; Li, Y.; Li, C.; Li, Z. M.; Li, X.; Li, X.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, L.; Ma, R.; Ma, Y. G.; Ma, G. L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; Meehan, K.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V.; Olvitt, D. L.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Peterson, A.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, S.; Raniwala, R.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Sharma, M. K.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B. J.; Sun, X.; Sun, X. M.; Sun, Z.; Sun, Y.; Surrow, B.; Svirida, D. N.; Szelezniak, M. A.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A. N.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Trzeciak, B. A.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbaek, F.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, F.; Wang, Y.; Wang, H.; Wang, J. S.; Wang, Y.; Wang, G.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, Y. F.; Xu, N.; Xu, Z.; Xu, Q. H.; Xu, H.; Yang, Y.; Yang, Y.; Yang, C.; Yang, S.; Yang, Q.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, X. P.; Zhang, J. B.; Zhang, J.; Zhang, Z.; Zhang, S.; Zhang, Y.; Zhang, J. L.; Zhao, F.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2015-11-01

    Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2 } and v2{4 }, for charged hadrons from U +U collisions at √{sNN }=193 GeV and Au +Au collisions at √{sNN}=200 GeV . Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v2{2 } on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U +U collisions. We also show that v2 vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.

  12. Predictions for {radical} (s) =200A; GeV Au+Au collisions from relativistic hydrodynamics

    SciTech Connect

    Schlei, B.R.; Schlei, B.R.; Strottman, D.

    1999-01-01

    The relativistic hydrodynamical model HYLANDER-C is used to give estimates for single inclusive particle momentum spectra in {radical} (s) =200 GeV/nucleon Au+Au collisions that will be investigated experimentally in the near future. The predictions are based on initial conditions that the initial fireball has a longitudinal extension of 1.6 fm and an initial energy density of 30.8 GeV/fm{sup 3} as obtained from a cascade model. For the collision energy considered here, different stopping scenarios are explored for the first time. Our calculations give particle yields of the order of 10thinsp000 to 20thinsp000 charged particles per event. {copyright} {ital 1999} {ital The American Physical Society}

  13. Dynamic aperture calculation for the RHIC 2010 100 GeV Au-Au run lattices

    SciTech Connect

    Luo, Y.; Brown, K.; Fischer, W.; Ptitsyn, V.; Roser, T.; Schoefer, V.; Tepikian, S.; Trbojevic, D.

    2010-08-01

    In this note we summarize the dynamic aperture calculation with the 2010 RHIC 100 GeV Au-Au run lattices. This study was initiated to understand the observed large beam decay in the Yellow ring after rf re-bucketing in the beginning of this run. The off-line linear lattice models and the interaction region non-linearity models are used. The large beam decay in the Yellow ring after re-bucketing was eventually eliminated by lowering the Yellow tunes to 0.21 from 0.235 with {beta}* = 0.7m lattice. In this note we only focus on the numeric simulation instead of the beam experiments.

  14. Pion-kaon femtoscopy in Au+Au collisions at STAR

    NASA Astrophysics Data System (ADS)

    Poniatowska, Katarzyna; STAR Collaboration

    2015-05-01

    In non-identical particle correlations, e.g. pion-kaon femtoscopy, one can obtain information about source size and asymmetry in emission processes of pions and kaons. Such asymmetry give us knowledge of which type of particles is emitted first/second and/or from which region of the source. The studies of non-identical particle femtoscopy for Beam Energy Scan energies give us the opportunity to study how the source size and asymmetry in particle emission depend on the initial conditions of the collision. It also allows one to examine these parameters in the vicinity of the theoretical critical point. In these proceedings, we present STAR results of pion-kaon femtoscopy at mid-rapidity in Au+Au collisions at \\sqrt{sNN} = 7.7, 19.6 and 39 GeV.

  15. Pion-kaon femtoscopy in Au+Au collisions at STAR

    NASA Astrophysics Data System (ADS)

    Poniatowska, Katarzyna

    2015-05-01

    Femtoscopy analysis allows us to extract information about the properties of particle emission source created after collision. From HBT of two correlated pions one can calculate source sizes; in addition, from the non-identical particle correlations, e.g. pion-kaon femtoscopy, one can obtain information not only about source sizes but the asymmetry in the emission processes of particles of different types as well. Such asymmetry gives knowledge of which kind of particles are emitted first/second and/or from which region of the source. The studies of non-identical particle femtoscopy for different collision energies gives us the opportunity to study how the source size and asymmetry in particle emission depend on the initial conditions of the collision. In these proceedings, we will present STAR results of pion-kaon femtoscopy at mid-rapidity in Au + Au collisions from the Beam Energy Scan program.

  16. Results from Vernier Scans in RHIC from 2001/02 Au-Au and pp Operation

    NASA Astrophysics Data System (ADS)

    Drees, Angelika; Xu, Zhangbu; Zhang, Haibin

    2002-10-01

    A series of Vernier Scans (or Van-der-Meer Scans) has been performed during the Au-Au run as well as the pp run at a beam energy of 100 GeV in RHIC during the 2001/02 operation period. During a scan one beam is swept across the other in the two transverse planes while collision rates are monitored as a function of beam displacement. Scans were done at various settings of beta* and various IRs. Maximum collision rate and transverse beam profiles are derived from a Gauss fit to the scan data. This report explains the method and summarizes the data taken during this operation period. first results from the fits are shown and compared to prediction and earlier runs.

  17. Charge transport in single Au / alkanedithiol / Au junctions: coordination geometries and conformational degrees of freedom.

    PubMed

    Li, Chen; Pobelov, Ilya; Wandlowski, Thomas; Bagrets, Alexei; Arnold, Andreas; Evers, Ferdinand

    2008-01-01

    Recent STM molecular break-junction experiments have revealed multiple series of peaks in the conductance histograms of alkanedithiols. To resolve a current controversy, we present here an in-depth study of charge transport properties of Au|alkanedithiol|Au junctions. Conductance histograms extracted from our STM measurements unambiguously confirm features showing more than one set of junction configurations. On the basis of quantum chemistry calculations, we propose that certain combinations of different sulfur-gold couplings and trans/gauche conformations act as the driving agents. The present study may have implications for experimental methodology: whenever conductances of different junction conformations are not statistically independent, the conductance histogram technique can exhibit a single series only, even though a much larger abundance of microscopic realizations exists. PMID:18076172

  18. Steering epitaxial alignment of Au, Pd, and AuPd nanowire arrays by atom flux change.

    PubMed

    Yoo, Youngdong; Seo, Kwanyong; Han, Sol; Varadwaj, Kumar S K; Kim, Hyun You; Ryu, Ji Hoon; Lee, Hyuck Mo; Ahn, Jae Pyoung; Ihee, Hyotcherl; Kim, Bongsoo

    2010-02-10

    We have synthesized epitaxial Au, Pd, and AuPd nanowire arrays in vertical or horizontal alignment on a c-cut sapphire substrate. We show that the vertical and horizontal nanowire arrays grow from half-octahedral seeds by the correlations of the geometry and orientation of seed crystals with those of as-grown nanowires. The alignment of nanowires can be steered by changing the atom flux. At low atom deposition flux vertical nanowires grow, while at high atom flux horizontal nanowires grow. Similar vertical/horizontal epitaxial growth is also demonstrated on SrTiO(3) substrates. This orientation-steering mechanism is visualized by molecular dynamics simulations. PMID:20050692

  19. From the ternary Eu(Au/In)2 and EuAu4(Au/In)2 with remarkable Au/In distributions to a new structure type: The gold-rich Eu5Au16(Au/In)6 structure

    SciTech Connect

    Steinberg, Simon; Card, Nathan; Mudring, Anja -Verena

    2015-08-13

    The ternary Eu(Au/In)2 (EuAu0.46In1.54(2)) (I), EuAu4(Au/In)2 (EuAu4+xIn2–x with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu5Au16(Au/In)6 (Eu5Au17.29In4.71(3)) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl4Mo2-type (tI14; I4/mmm; Z = 2; a = 7.1612(7) Å; c = 5.5268(7) Å) and exhibit significant Au/In disorder. I is composed of an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squared Au8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu5Au16(Au/In)6 (Eu5Au17.29In4.71(3)) (oS108; Cmcm; Z = 4; a = 7.2283(4) Å; b = 9.0499(6) Å; c = 34.619(2) Å), which formally represents a one-dimensional intergrowth of the series EuAu2–“EuAu4In2”. The site preferences of the disordered Au/In positions in II were investigated for different hypothetical “EuAu4(Au/In)2” models using the projector-augmented wave method and indicate that these structures attempt to optimize the frequencies of the heteroatomic Au–In contacts. Furthermore, a chemical bonding analysis on two “EuAu5In” and “EuAu4In2” models employed the TB-LMTO-ASA method and reveals that the subtle interplay between the local atomic environments and the bond energies determines the structural and site preferences for these systems.

  20. A comparative study of the Au + H2, Au+ + H2, and Au- + H2 systems: Potential energy surfaces and dynamics of reactive collisions

    NASA Astrophysics Data System (ADS)

    Dorta-Urra, Anaís; Zanchet, Alexandre; Roncero, Octavio; Aguado, Alfredo

    2015-04-01

    In order to study the Au- + H2 collision, a new global potential energy surface (PES) describing the ground electronic state of AuH 2- system is developed and compared with the PESs of the neutral [Zanchet et al., J. Chem. Phys. 132, 034301 (2010)] and cationic systems [Anaís et al., J. Chem. Phys. 135, 091102 (2011)]. We found that Au- - H2 presents a H-Au-H insertion minimum attributed to the stabilization of the LUMO 3b2 orbital, which can be considered as the preamble of the chemisorption well appearing in larger gold clusters. While the LUMO orbital is stabilized, the HOMO 6a1 is destabilized, creating a barrier at the geometry where the energy orbitals' curves are crossing. In the anion, this HOMO is doubly occupied, while in the neutral system is half-filled and completely empty in the cation, explaining the gradual disappearance of the well and the barrier as the number of electrons decreases. The cation presents a well in the entrance channel partially explained by electrostatic interactions. The three systems' reactions are highly endothermic, by 1.66, 2.79, and 3.23 eV for AuH, AuH+, and AuH- products, respectively. The reaction dynamics is studied using quasi-classical trajectory method for the three systems. The one corresponding to the anionic system is new in this work. Collision energies between 1.00 and 8.00 eV, measured for the cation, are in good agreement with the simulated cross section for the AuH+. It was also found that the total fragmentation, in three atoms, competes becoming dominant at sufficiently high energy. Here, we study the competition between the two different reaction pathways for the anionic, cationic, and neutral species, explaining the differences using a simple model based on the topology of the potential energy surfaces.

  1. Biosynthesis of Au, Ag and Au-Ag nanoparticles using edible mushroom extract.

    PubMed

    Philip, Daizy

    2009-07-15

    Integration of green chemistry principles to nanotechnology is one of the key issues in nanoscience research. There is growing need to develop environmentally benign metal nanoparticle synthesis process that do not use toxic chemicals in the synthesis protocols to avoid adverse effects in medical applications. Here, it is a report on extracellular synthesis method for the preparation of Au, Ag and Au-Ag nanoparticles in water, using the extract of Volvariella volvacea, a naturally occurring edible mushroom, as reducing and protecting agents. Gold nanoparticles of different sizes (20-150 nm) and shapes from triangular nanoprisms to nearly spherical and hexagonal are obtained by this novel method. The size and shape of gold nanoparticles are also found to depend on temperature of the extract. The silver nanoparticles are spherical with size approximately 15 nm. There is increased productivity of nanoparticles as shown by sharp and intense surface plasmon resonance bands for the nanoparticles prepared using an excess of the extract. The Au-Ag nanoparticles prepared by co-reduction has only one plasmon band due to alloying of the constituents. All the synthesized nanoparticles are found to be photoluminescent and are highly crystalline as shown by SAED and XRD patterns with fcc phase oriented along the (111) plane. FTIR measurements were carried out to identify the possible biomolecules responsible for capping and efficient stabilization of the nanoparticles. It is found that Au nanoparticles are bound to proteins through free amino groups and silver nanoparticles through the carboxylate group of the amino acid residues. The position and intensity of the emission band is found to depend on composition of the nanoparticles indicating the possible use in therapeutic applications. PMID:19324587

  2. Biosynthesis of Au, Ag and Au-Ag nanoparticles using edible mushroom extract

    NASA Astrophysics Data System (ADS)

    Philip, Daizy

    2009-07-01

    Integration of green chemistry principles to nanotechnology is one of the key issues in nanoscience research. There is growing need to develop environmentally benign metal nanoparticle synthesis process that do not use toxic chemicals in the synthesis protocols to avoid adverse effects in medical applications. Here, it is a report on extracellular synthesis method for the preparation of Au, Ag and Au-Ag nanoparticles in water, using the extract of Volvariella volvacea, a naturally occurring edible mushroom, as reducing and protecting agents. Gold nanoparticles of different sizes (20-150 nm) and shapes from triangular nanoprisms to nearly spherical and hexagonal are obtained by this novel method. The size and shape of gold nanoparticles are also found to depend on temperature of the extract. The silver nanoparticles are spherical with size ˜15 nm. There is increased productivity of nanoparticles as shown by sharp and intense surface plasmon resonance bands for the nanoparticles prepared using an excess of the extract. The Au-Ag nanoparticles prepared by co-reduction has only one plasmon band due to alloying of the constituents. All the synthesized nanoparticles are found to be photoluminescent and are highly crystalline as shown by SAED and XRD patterns with fcc phase oriented along the (1 1 1) plane. FTIR measurements were carried out to identify the possible biomolecules responsible for capping and efficient stabilization of the nanoparticles. It is found that Au nanoparticles are bound to proteins through free amino groups and silver nanoparticles through the carboxylate group of the amino acid residues. The position and intensity of the emission band is found to depend on composition of the nanoparticles indicating the possible use in therapeutic applications.

  3. Tunneling characteristics of Au-alkanedithiol-Au junctions formed via nanotransfer printing (nTP).

    PubMed

    Niskala, Jeremy R; Rice, William C; Bruce, Robert C; Merkel, Timothy J; Tsui, Frank; You, Wei

    2012-07-25

    Construction of permanent metal-molecule-metal (MMM) junctions, though technically challenging, is desirable for both fundamental investigations and applications of molecule-based electronics. In this study, we employed the nanotransfer printing (nTP) technique using perfluoropolyether (PFPE) stamps to print Au thin films onto self-assembled monolayers (SAMs) of alkanedithiol formed on Au thin films. We show that the resulting MMM junctions form permanent and symmetrical tunnel junctions, without the need for an additional protection layer between the top metal electrode and the molecular layer. This type of junction makes it possible for direct investigations into the electrical properties of the molecules and the metal-molecule interfaces. Dependence of transport properties on the length of the alkane molecules and the area of the printed Au electrodes has been examined systematically. From the analysis of the current-voltage (I-V) curves using the Simmons model, the height of tunneling barrier associated with the molecule (alkane) has been determined to be 3.5 ± 0.2 eV, while the analysis yielded an upper bound of 2.4 eV for the counterpart at the interface (thiol). The former is consistent with the theoretical value of ~3.5-5.0 eV. The measured I-V curves show scaling with respect to the printed Au electrode area with lateral dimensions ranging from 80 nm to 7 μm. These results demonstrate that PFPE-assisted nTP is a promising technique for producing potentially scalable and permanent MMM junctions. They also demonstrate that MMM structures (produced by the unique PFPE-assisted nTP) constitute a reliable test bed for exploring molecule-based electronics. PMID:22720785

  4. {phi} meson production in Au + Au and p + p collisions at {radical}s{sub NN}=200 GeV

    SciTech Connect

    Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Arkhipkin, D.; Averichev, G.S.; Badyal, S.K.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bezverkhny, B.I.; Bhardwaj, S.; Bhati, A.K.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Botje, M.; Boucham, A.; Brandin, A.; Bravar, A.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Carroll, J.; Castillo, J.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dubey, A.K.; Dunin, V.B.; Dunlop, J.C.; Dutta Majumdar, M.R.; Eckardt, V.; Efimov, L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Filip, P.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Gagunashvili, N.; Gans, J.; Ganti, M.S.; Gaudichet, L.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Grachov, O.; Grebenyuk, O.; Gronstal, S.; Grosnick, D.; Guedon, M.; Guertin, S.M.; Gupta, A.; Gutierrez, T.D.; Hallman, T.J.; Hamed, A.; Hardtke, D.; Harris, J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Huang, S.L.; Hughes, E.; Humanic, T.J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kaplan, M.; Keane, D.; Khodyrev; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Koetke, D.D.; Kollegger, T.; Kopytine, S.M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, P.; Kravstov, V.I.; Krueger, K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; Kunde, G.J.; Kunz, C.L.; Kutuev, R.Kh.; et al.

    2004-06-01

    We report the STAR measurement of {psi} meson production in Au + Au and p + p collisions at {radical}s{sub NN} = 200 GeV. Using the event mixing technique, the {psi} spectra and yields are obtained at midrapidity for five centrality bins in Au+Au collisions and for non-singly-diffractive p+p collisions. It is found that the {psi} transverse momentum distributions from Au+Au collisions are better fitted with a single-exponential while the p+p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that {psi} production in central Au+Au collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions (). The systematics of versus centrality and the constant {psi}/K{sup -} ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for {psi} production.

  5. Charged particle multiplicity fluctuations in Au+Au collisions at \\sqrt{s_{NN}} = 200\\, {\\rm GeV}

    NASA Astrophysics Data System (ADS)

    Wozniak, Krzysztof; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J. L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wuosmaa, A. H.; Wyslouch, B.

    2004-08-01

    This paper presents the first PHOBOS results on charged particle multiplicity fluctuations measured for Au+Au collisions at the highest RHIC energy within a wide pseudorapidity range of |eegr| < 3. The dependence on collision geometry is removed in the analysis by using the normalized difference between the number of particles in separate eegr bins. We compare our data to HIJING model predictions.

  6. CO Oxidation mechanism on CeO2-supported Au nanoclusters

    SciTech Connect

    Kim H. Y.; Henkelman, G.

    2013-09-08

    To reveal the richer chemistry of CO oxidation by CeO2 supported Au Nanoclusters(NCs)/Nanoparticles, we design Au13 and Au12 supported on a flat and a stepped-CeO2 model (Au/CeO2) and study various kinds of CO oxidation mechanisms at the Au-CeO2 interface and the Au NC as well.

  7. Electronic and resonance Raman spectra of [Au2(CS3)2]2-. Spectroscopic properties of a "short" Au(I)-Au(I) bond.

    PubMed

    Cheng, E C; Leung, K H; Miskowski, V M; Yam, V W; Phillips, D L

    The anion [Au2(CS3)2]2- has an unusually short Au-Au distance (2.80 A) for a binuclear Au(I) complex. We report detailed Raman studies of the nBu4N+ salt of this complex, including FT-Raman of the solid and UV/vis resonance Raman of dimethyl sulfoxide solutions. All five totally symmetric vibrations of the anion have been located and assigned. A band at delta nu = 125 cm-1 is assigned to nu (Au2). The visible-region electronic absorption bands (384 (epsilon 30,680) and 472 nm (epsilon 610 M-1 cm-1)) are attributable to CS3(2-) localized transitions, as confirmed by the dominance of nu sym(C-Sexo) (delta nu = 951 cm-1) in RR spectra measured in this region. An absorption band at 314 nm (22,250 M-1 cm-1) is assigned as the metal-metal 1(d sigma*-->p sigma) transition, largely because nu sym(C-Sexo) is not strongly enhanced in RR involving this band. Observation of the expected strong resonance enhancement of nu (Au2) was precluded as a result of masking by intense solvent Rayleigh scattering in the UV. PMID:11196834

  8. A Bis(Diphosphanyl N-Heterocyclic Carbene) Gold Complex: A Synthon for Luminescent Rigid AuAg2 Arrays and Au5 and Cu6 Double Arrays.

    PubMed

    Ai, Pengfei; Mauro, Matteo; De Cola, Luisa; Danopoulos, Andreas A; Braunstein, Pierre

    2016-03-01

    A mononuclear bis(NHC)/Au(I) (NHC=N-heterocyclic carbene) cationic complex with a rigid bis(phosphane)-functionalized NHC ligand (PCNHC P) was used to construct linear Au3 and Ag2 Au arrays, a Au5 cluster with two intersecting crosslike Au3 arrays, and an unprecedented Cu6 complex with two parallel Cu3 arrays. The impact of metallophilic interactions on photoluminescence was studied experimentally. PMID:26823329

  9. Stream dynamics between 1 AU and 2 AU: A detailed comparison of observations and theory

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Pizzo, V.; Lazarus, A.; Gazis, P. R.

    1984-01-01

    A radial alignment of three solar wind stream structures observed by IMP-7 and -8 (at 1.0 AU) and Voyager 1 and 2 (in the range 1.4 to 1.8 AU) in late 1977 is presented. It is demonstrated that several important aspects of the observed dynamical evolution can be both qualitatively and quantitatively described with a single-fluid 2-D MHD numerical model of quasi-steady corotating flow, including accurate prediction of: (1) the formation of a corotating shock pair at 1.75 AU in the case of a simple, quasi-steady stream; (2) the coalescence of the thermodynamic and magnetic structures associated with the compression regions of two neighboring, interacting, corotating streams; and (3) the dynamical destruction of a small (i.e., low velocity-amplitude, short spatial-scale) stream by its overtaking of a slower moving, high-density region associated with a preceding transient flow. The evolution of these flow systems is discussed in terms of the concepts of filtering and entrainment.

  10. Neutral pion production in Au+Au collisions at sNN=200 GeV

    NASA Astrophysics Data System (ADS)

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Alakhverdyants, A. V.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D. R.; Bellwied, R.; Benedosso, F.; Betancourt, M. J.; Betts, R. R.; Bhasin, A.; Bhati, A. K.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Biritz, B.; Bland, L. C.; Bnzarov, I.; Bombara, M.; Bonner, B. E.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bruna, E.; Bueltmann, S.; Burton, T. P.; Bystersky, M.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, J. Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K. E.; Christie, W.; Clarke, R. F.; Codrington, M. J. M.; Corliss, R.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; Silva, L. C. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; de Souza, R. Derradi; Didenko, L.; Djawotho, P.; Dogra, S. M.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Efimov, L. G.; Elhalhuli, E.; Elnimr, M.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gaillard, L.; Gangadharan, D. R.; Ganti, M. S.; Garcia-Solis, E. J.; Geromitsos, A.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y. N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S. M.; Guimaraes, K. S. F. F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T. J.; Hamed, A.; Harris, J. W.; He, W.; Heinz, M.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A. M.; Hoffmann, G. W.; Hofman, D. J.; Hollis, R. S.; Huang, H. Z.; Humanic, T. J.; Huo, L.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W. W.; Jakl, P.; Jena, C.; Jin, F.; Jones, C. L.; Jones, P. G.; Joseph, J.; Judd, E. G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitan, J.; Kauder, K.; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V. Yu.; Kikola, D. P.; Kiryluk, J.; Kisiel, A.; Klein, S. R.; Knospe, A. G.; Kocoloski, A.; Koetke, D. D.; Konzer, J.; Kopytine, M.; Koralt, I.; Korsch, W.; Kotchenda, L.; Kouchpil, V.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M. A. C.; Landgraf, J. M.; Lapointe, S.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lee, J. H.; Leight, W.; Levine, M. J.; Li, C.; Li, N.; Li, Y.; Lin, G.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W. J.; Longacre, R. S.; Love, W. A.; Lu, Y.; Ludlam, T.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Mall, O. I.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; Matulenko, Yu. A.; McDonald, D.; McShane, T. S.; Meschanin, A.; Milner, R.; Minaev, N. G.; Mioduszewski, S.; Mischke, A.; Mohanty, B.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nattrass, C.; Nayak, T. K.; Nelson, J. M.; Netrakanti, P. K.; Ng, M. J.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B. S.; Pal, S. K.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S. C.; Pile, P.; Planinic, M.; Ploskon, M. A.; Pluta, J.; Plyku, D.; Poljak, N.; Poskanzer, A. M.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Pruthi, N. K.; Pujahari, P. R.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Redwine, R.; Reed, R.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakai, S.; Sakrejda, I.; Sakuma, T.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S. S.; Shi, X.-H.; Sichtermann, E. P.; Simon, F.; Singaraju, R. N.; Skoby, M. J.; Smirnov, N.; Sorensen, P.; Sowinski, J.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Suarez, M. C.; Subba, N. L.; Sumbera, M.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T. J. M.; de Toledo, A. Szanto; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarini, L. H.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Tian, J.; Timmins, A. R.; Timoshenko, S.; Tlusty, D.; Tokarev, M.; Trainor, T. A.; Tram, V. N.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; Nieuwenhuizen, G. Van; Vanfossen, J. A., Jr.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Videbaek, F.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, Q.; Wang, X.; Wang, X. L.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Whitten, C., Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xie, W.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yang, Y.; Yepes, P.; Yip, K.; Yoo, I.-K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, S.; Zhang, W. M.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zhu, X.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zuo, J. X.

    2009-10-01

    The results of midrapidity (0Au collisions, measured by the STAR experiment, are presented. The neutral pions are reconstructed from photons measured either by the STAR Barrel Electro-Magnetic Calorimeter or by the Time Projection Chamber via tracking of conversion electron-positron pairs. Our measurements are compared to previously published π± and π0 results. The nuclear modification factors RCP and RAA of π0 are also presented as a function of pT. In the most central Au+Au collisions, the binary collision scaled π0 yield at high pT is suppressed by a factor of about 5 compared to the expectation from the yield of p+p collisions. Such a large suppression is in agreement with previous observations for light quark mesons and is consistent with the scenario that partons suffer considerable energy loss in the dense medium formed in central nucleus-nucleus collisions at the Relativistic Heavy Ion Collider.

  11. Observation of D0 meson nuclear modifications in Au+Au collisions at sNN=200 GeV

    DOE PAGESBeta

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; et al

    2014-09-30

    We report the first measurement of charmed-hadron (D0) production via the hadronic decay channel (D0→K-+π+) in Au+Au collisions at √sNN=200 GeV with the STAR experiment. The charm production cross section per nucleon-nucleon collision at midrapidity scales with the number of binary collisions, Nbin, from p+p to central Au+Au collisions. The D0 meson yields in central Au+Aucollisions are strongly suppressed compared to those in p+p scaled by Nbin, for transverse momenta pT>3 GeV/c, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate pT is also observed. Model calculations including strong charm-medium interactions andmore » coalescence hadronization describe our measurements.« less

  12. Autonomous Repair Mechanism of Creep Damage in Fe-Au and Fe-Au-B-N Alloys

    NASA Astrophysics Data System (ADS)

    Zhang, S.; Kwakernaak, C.; Tichelaar, F. D.; Sloof, W. G.; Kuzmina, M.; Herbig, M.; Raabe, D.; Brück, E.; van der Zwaag, S.; van Dijk, N. H.

    2015-12-01

    The autonomous repair mechanism of creep cavitation during high-temperature deformation has been investigated in Fe-Au and Fe-Au-B-N alloys. Combined electron-microscopy techniques and atom probe tomography reveal how the improved creep properties result from Au precipitation within the creep cavities, preferentially formed on grain boundaries oriented perpendicular to the applied stress. The selective precipitation of Au atoms at the free creep cavity surface results in pore filling, and thereby, autonomous repair of the creep damage. The large difference in atomic size between the Au and Fe strongly hampers the nucleation of precipitates in the matrix. As a result, the matrix acts as a reservoir for the supersaturated solute until damage occurs. Grain boundaries and dislocations are found to act as fast transport routes for solute gold from the matrix to the creep cavities. The mechanism responsible for the self-healing can be characterized by a simple model for cavity growth and cavity filling.

  13. Wafer-level Au-Au bonding in the 350-450 °C temperature range

    NASA Astrophysics Data System (ADS)

    Tofteberg, Hannah R.; Schjølberg-Henriksen, Kari; Fasting, Eivind J.; Moen, Alexander S.; Taklo, Maaike M. V.; Poppe, Erik U.; Simensen, Christian J.

    2014-08-01

    Metal thermocompression bonding is a hermetic wafer-level packaging technology that facilitates vertical integration and shrinks the area used for device sealing. In this paper, Au-Au bonding at 350, 400 and 450 °C has been investigated, bonding wafers with 1 µm Au on top of 200 nm TiW. Test Si laminates with device sealing frames of 100, 200, and 400 µm in width were realized. Bond strengths measured by pull tests ranged from 8 to 102 MPa and showed that the bond strength increased with higher bonding temperatures and decreased with increasing frame width. Effects of eutectic reactions, grain growth in the Au film and stress relaxation causing buckles in the TiW film were most pronounced at 450 °C and negligible at 350 °C. Bond temperature below the Au-Si eutectic temperature 363 °C is recommended.

  14. Electronic and geometric structures of Au30 clusters: a network of 2e-superatom Au cores protected by tridentate protecting motifs with u3-S

    NASA Astrophysics Data System (ADS)

    Tian, Zhimei; Cheng, Longjiu

    2015-12-01

    Density functional theory calculations have been performed to study the experimentally synthesized Au30S(SR)18 and two related Au30(SR)18 and Au30S2(SR)18 clusters. The patterns of thiolate ligands on the gold cores for the three thiolate-protected Au30 nanoclusters are on the basis of the ``divide and protect'' concept. A novel extended protecting motif with u3-S, S(Au2(SR)2)2AuSR, is discovered, which is termed the tridentate protecting motif. The Au cores of Au30S(SR)18, Au30(SR)18 and Au30S2(SR)18 clusters are Au17, Au20 and Au14, respectively. The superatom-network (SAN) model and the superatom complex (SAC) model are used to explain the chemical bonding patterns, which are verified by chemical bonding analysis based on the adaptive natural density partitioning (AdNDP) method and aromatic analysis on the basis of the nucleus-independent chemical shift (NICS) method. The Au17 core of the Au30S(SR)18 cluster can be viewed as a SAN of one Au6 superatom and four Au4 superatoms. The shape of the Au6 core is identical to that revealed in the recently synthesized Au18(SR)14 cluster. The Au20 core of the Au30(SR)18 cluster can be viewed as a SAN of two Au6 superatoms and four Au4 superatoms. The Au14 core of Au30S2(SR)18 can be regarded as a SAN of two pairs of two vertex-sharing Au4 superatoms. Meanwhile, the Au14 core is an 8e-superatom with 1S21P6 configuration. Our work may aid understanding and give new insights into the chemical synthesis of thiolate-protected Au clusters.Density functional theory calculations have been performed to study the experimentally synthesized Au30S(SR)18 and two related Au30(SR)18 and Au30S2(SR)18 clusters. The patterns of thiolate ligands on the gold cores for the three thiolate-protected Au30 nanoclusters are on the basis of the ``divide and protect'' concept. A novel extended protecting motif with u3-S, S(Au2(SR)2)2AuSR, is discovered, which is termed the tridentate protecting motif. The Au cores of Au30S(SR)18, Au30(SR)18 and Au30S

  15. Medium-sized Au40(SR)24 and Au52(SR)32 nanoclusters with distinct gold-kernel structures and spectroscopic features

    NASA Astrophysics Data System (ADS)

    Xu, Wen Wu; Li, Yadong; Gao, Yi; Zeng, Xiao Cheng

    2016-01-01

    We have analyzed the structures of two medium-sized thiolate-protected gold nanoparticles (RS-AuNPs) Au40(SR)24 and Au52(SR)32 and identified the distinct structural features in their Au kernels [Sci. Adv., 2015, 1, e1500425]. We find that both Au kernels of the Au40(SR)24 and Au52(SR)32 nanoclusters can be classified as interpenetrating cuboctahedra. Simulated X-ray diffraction patterns of the RS-AuNPs with the cuboctahedral kernel are collected and then compared with the X-ray diffraction patterns of the RS-AuNPs of two other prevailing Au-kernels identified from previous experiments, namely the Ino-decahedral kernel and icosahedral kernel. The distinct X-ray diffraction patterns of RS-AuNPs with the three different types of Au-kernels can be utilized as signature features for future studies of structures of RS-AuNPs. Moreover, the simulated UV/Vis absorption spectra and Kohn-Sham orbital energy-level diagrams are obtained for the Au40(SR)24 and Au52(SR)32, on the basis of time-dependent density functional theory computation. The extrapolated optical band-edges of Au40(SR)24 and Au52(SR)32 are 1.1 eV and 1.25 eV, respectively. The feature peaks in the UV/Vis absorption spectra of the two clusters can be attributed to the d --> sp electronic transition. Lastly, the catalytic activities of the Au40(SR)24 and Au52(SR)32 are examined using CO oxidation as a probe. Both medium-sized thiolate-protected gold clusters can serve as effective stand-alone nanocatalysts.We have analyzed the structures of two medium-sized thiolate-protected gold nanoparticles (RS-AuNPs) Au40(SR)24 and Au52(SR)32 and identified the distinct structural features in their Au kernels [Sci. Adv., 2015, 1, e1500425]. We find that both Au kernels of the Au40(SR)24 and Au52(SR)32 nanoclusters can be classified as interpenetrating cuboctahedra. Simulated X-ray diffraction patterns of the RS-AuNPs with the cuboctahedral kernel are collected and then compared with the X-ray diffraction patterns of the RS-Au

  16. Medium-sized Au40(SR)24 and Au52(SR)32 nanoclusters with distinct gold-kernel structures and spectroscopic features.

    PubMed

    Xu, Wen Wu; Li, Yadong; Gao, Yi; Zeng, Xiao Cheng

    2016-01-21

    We have analyzed the structures of two medium-sized thiolate-protected gold nanoparticles (RS-AuNPs) Au40(SR)24 and Au52(SR)32 and identified the distinct structural features in their Au kernels [Sci. Adv., 2015, 1, e1500425]. We find that both Au kernels of the Au40(SR)24 and Au52(SR)32 nanoclusters can be classified as interpenetrating cuboctahedra. Simulated X-ray diffraction patterns of the RS-AuNPs with the cuboctahedral kernel are collected and then compared with the X-ray diffraction patterns of the RS-AuNPs of two other prevailing Au-kernels identified from previous experiments, namely the Ino-decahedral kernel and icosahedral kernel. The distinct X-ray diffraction patterns of RS-AuNPs with the three different types of Au-kernels can be utilized as signature features for future studies of structures of RS-AuNPs. Moreover, the simulated UV/Vis absorption spectra and Kohn-Sham orbital energy-level diagrams are obtained for the Au40(SR)24 and Au52(SR)32, on the basis of time-dependent density functional theory computation. The extrapolated optical band-edges of Au40(SR)24 and Au52(SR)32 are 1.1 eV and 1.25 eV, respectively. The feature peaks in the UV/Vis absorption spectra of the two clusters can be attributed to the d → sp electronic transition. Lastly, the catalytic activities of the Au40(SR)24 and Au52(SR)32 are examined using CO oxidation as a probe. Both medium-sized thiolate-protected gold clusters can serve as effective stand-alone nanocatalysts. PMID:26676095

  17. Ge-Au eutectic bonding of Ge {100} single crystals

    NASA Astrophysics Data System (ADS)

    Knowlton, W. B.; Itoh, K. M.; Beeman, J. W.; Emes, J. H.; Loretto, D.; Haller, E. E.

    1993-11-01

    We present preliminary results on the eutectic bonding between two {100} Ge single crystal surfaces using thin films of Au ranging from 900Å/surface to 300Å/surface and Pd (10% the thickness of Au). Following bonding, plan view optical microscopy (OM) of the cleaved interface of samples with Au thicknesses ≤ 500Å/surface show a eutectic morphology more conducive to phonon transmission through the bond interface. High resolution transmission electron microscopy (HRTEM) cross sectional interface studies of a 300Å/surface Au sample show <100> epitaxial growth of Ge. In sections of the bond, lattice continuity of the Ge is apparent through the interface. TEM studies also reveal <110> heteroepitaxial growth of Au with a Au-Ge lattice mismatch of less than 2%. Eutectic bonds with 200Å/surface Au have been attained with characterization pending. An optical polishing technique for Ge has been optimized to insure intimate contact between the Ge surfaces prior to bonding. Interferometry analysis of the optically polished Ge surface shows that surface height fluctuations lie within ±150Å across an interval of 1mm. Characterization of phonon transmission through the interface is discussed with respect to low temperature detection of ballistic phonons.

  18. Tailoring the FeRh magnetostructural response with Au diffusion

    NASA Astrophysics Data System (ADS)

    Loving, M.; de Vries, M. A.; Jimenez-Villacorta, F.; Le Graët, C.; Liu, X.; Fan, R.; Langridge, S.; Heiman, D.; Marrows, C. H.; Lewis, L. H.

    2012-08-01

    Factors which contribute to magnetostructural transition control have been demonstrated by study of the effects of Au incorporation on the magnetic and structural character of CsCl-structured equiatomic FeRh thin films. Sputtered films were capped with 2 nm of Au deposited at 873 K and at 323 K and subsequently characterized with magnetometry and synchrotron-based structural probes. Diffusion of Au into the FeRh film layer at 873 K is confirmed by a reduction in the Au capping layer thickness relative to the film capped at 323 K. The impact of Au diffusion on the FeRh magnetostructural character is noted by a decrease in the onset of the transition temperature, a thermally broadened first-order transition and an increased sensitivity of the transition to applied magnetic field. Additionally, magnetization data indicate that Au diffusion causes retention of the ferromagnetic phase well below the normal magnetostructural transition temperature. These results are attributed to a multiphase FeRh film layer created by thermally driven Au diffusion.

  19. Electronic and chemical properties of supported Au nanoparticles

    NASA Astrophysics Data System (ADS)

    Lim, Dong Chan; Lopez-Salido, Ignacio; Dietsche, Rainer; Bubek, Moritz; Kim, Young Dok

    2006-11-01

    Oxidation and reduction behaviors of Au nanoparticles with different sizes on highly ordered pyrolytic graphite (HOPG) and silica were studied using X-ray photoelectron spectroscopy (XPS). For Au nanoparticles smaller than ˜6 nm in diameter, we found a novel oxygen species formed in Au nanoparticles, which is absent in larger particles and Au bulk crystals. This new oxygen species is attributed to the subsurface oxygen: for a complete understanding of the structures of catalytically active Au, the new oxygen species should be taken into account. In this context, it is worth mentioning that the subsurface oxygen species has been suggested to play an important role in heterogeneous catalysis. With decreasing Au particle size, a positive core level shift can be observed, which can be mostly attributed to the final state effects. Increase of the number of undercoordinated atoms with decreasing particle size is evidenced by a reduced splitting between 5d 3/2 and 5d 5/2 states and a band narrowing. Our results on electronic structures of Au nanoparticles on silica are compared to those on other substrates such as zirconia and titania to shed light onto the metal-support interactions.

  20. Enantiospecific adsorption of cysteine on a chiral Au34 cluster

    NASA Astrophysics Data System (ADS)

    Pelayo, José de Jesús; Valencia, Israel; Díaz, Gabriela; López-Lozano, Xóchitl; Garzón, Ignacio L.

    2015-12-01

    The interaction of biological molecules like chiral amino acids with chiral metal clusters is becoming an interesting and active field of research because of its potential impact in, for example, chiral molecular recognition phenomena. In particular, the enantiospecific adsorption (EA) of cysteine (Cys) on a chiral Au55 cluster was theoretically predicted a few years ago. In this work, we present theoretical results, based on density functional theory, of the EA of non-zwitterionic cysteine interacting with the C3-Au34 chiral cluster, which has been experimentally detected in gas phase, using trapped ion electron diffraction. Our results show that, indeed, the adsorption energy of the amino acid depends on which enantiomers participate in the formation Cys-Au34 chiral complex. EA was obtained in the adsorption modes where both the thiol, and the thiol-amino functional groups of Cys are adsorbed on low-coordinated sites of the metal cluster surface. Similarly to what was obtained for the Cys-Au55 chiral complex, in the present work, it is found that the EA is originated from the different strength and location of the bond between the COOH functional group and surface Au atoms of the Au34 chiral cluster. Calculations of the vibrational spectrum for the different Cys-Au34 diastereomeric complexes predict the existence of a vibro-enantiospecific effect, indicating that the vibrational frequencies of the adsorbed amino acid depend on its handedness.

  1. Présentations de l'adénite tuberculeuse de la tête et du cou au CHU de Bobo-Dioulasso, Burkina Faso

    PubMed Central

    Béogo, Rasmané; Birba, Noraogo Emile; Coulibaly, Toua Antoine; Traoré, Ibraïma; Ouoba, Kampadilemba

    2013-01-01

    Les ganglions de la tête et du cou sont parmi les localisations les plus fréquentes de la tuberculose, un problème de santé publique dans le monde. Une étude rétrospective conduite entre 2001 et 2010 rapporte les caractéristiques épidémiologiques et cliniques de l'adénite tuberculeuse de la tête et du cou, au CHU Sanou Souro, au Burkina Faso. Au total, 115 patients ont été observés dont l'âge était compris entre 2 ans et 64 ans (moyenne 31,46 ans). Il y avait 53 patients de sexe masculin (46,1%) et 62 de sexe féminin (53,9%). Un pic de fréquence de 39,8% était observé entre 30 et 39 ans. Les adénopathies cervicales étaient multiples chez 96,5% des patients et abcédées chez 30%. Elles étaient associées à des adénopathies extra cervicales chez 16,6% des patients. Chez 83,4% des patients, il a été noté un ou plusieurs signes à type d'asthénie et ou d'amaigrissement (70,8%), de fièvre 25% ou de toux (20,8%). L'infection associée la plus fréquente était celle par le VIH, observée chez 43,3% des patients. Les résultats de cette étude commandent la recherche systématique de l'infection par le VIH chez tout patient porteur d'adénite cervicale tuberculeuse dans un contexte de double endémicité de la tuberculose et de l'infection à VIH. PMID:24319521

  2. Structural, electronic and magnetic properties of Au-based monolayer derivatives in honeycomb structure

    NASA Astrophysics Data System (ADS)

    Kapoor, Pooja; Sharma, Munish; Kumar, Ashok; Ahluwalia, P. K.

    2016-05-01

    We present electronic properties of atomic layer of Au, Au2-N, Au2-O and Au2-F in graphene-like structure within the framework of density functional theory (DFT). The lattice constant of derived monolayers are found to be higher than the pristine Au monolayer. Au monolayer is metallic in nature with quantum ballistic conductance calculated as 4G0. Similarly, Au2-N and Au2-F monolayers show 4G0 and 2G0 quantum conductance respectively while semiconducting nature with calculated band gap of 0.28 eV has been observed for Au2-O monolayer. Most interestingly, half metalicity has been predicted for Au2-N and Au2-F monolayers. Our findings may have importance for the application of these monolayers in nanoelectronic and spintronics.

  3. First principles calculations of the optical and plasmonic response of Au alloys and intermetallic compounds.

    PubMed

    Keast, V J; Barnett, R L; Cortie, M B

    2014-07-30

    Pure Au is widely used in plasmonic applications even though its use is compromised by significant losses due to damping. There are some elements that are less lossy than Au (e.g. Ag or Al) but they will normally oxidize or corrode under ambient conditions. Here we examine whether alloying Au with a second element would be beneficial for plasmonic applications. In order to evaluate potential alternatives to pure Au, the density of states (DOS), dielectric function and plasmon quality factor have been calculated for alloys and compounds of Au with Al, Cd, Mg, Pd, Pt, Sn, Ti, Zn and Zr. Substitutional alloying of Au with Al, Cd, Mg and Zn was found to slightly improve the plasmonic response. Of the large number of intermetallic compounds studied, only AuAl2, Au3Cd, AuMg, AuCd and AuZn were found to be suitable for plasmonic applications. PMID:25001413

  4. First principles calculations of the optical and plasmonic response of Au alloys and intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Keast, V. J.; Barnett, R. L.; Cortie, M. B.

    2014-07-01

    Pure Au is widely used in plasmonic applications even though its use is compromised by significant losses due to damping. There are some elements that are less lossy than Au (e.g. Ag or Al) but they will normally oxidize or corrode under ambient conditions. Here we examine whether alloying Au with a second element would be beneficial for plasmonic applications. In order to evaluate potential alternatives to pure Au, the density of states (DOS), dielectric function and plasmon quality factor have been calculated for alloys and compounds of Au with Al, Cd, Mg, Pd, Pt, Sn, Ti, Zn and Zr. Substitutional alloying of Au with Al, Cd, Mg and Zn was found to slightly improve the plasmonic response. Of the large number of intermetallic compounds studied, only AuAl2, Au3Cd, AuMg, AuCd and AuZn were found to be suitable for plasmonic applications.

  5. Crystal Structure of the PdAu24(SR)18(0) Superatom.

    PubMed

    Tofanelli, Marcus A; Ni, Thomas W; Phillips, Billy D; Ackerson, Christopher J

    2016-02-01

    The single-crystal X-ray structure of Pd-doped Au25(SR)18 was solved. The crystal structure reveals that in PdAu24(SR)18, the Pd atom is localized only to the centroid of the Au25(SR)18 cluster. This single-crystal X-ray structure shows that PdAu24(SR)18(0) is well conceptualized with the superatom theory. The PdAu24(SR)18(0) charge state is isoelectronic with Au25(SR)18(+1) as determined by a first order Jahn-Teller effect of similar magnitude and by electrochemical comparison. The previously reported increased stability of PdAu24(SR)18 can be rationalized in terms of Pd-Au bonds that are shorter than the Au-Au bonds in Au25(SR)18. PMID:26760220

  6. Mass spectrometric determination of the dissociation energy of the AuMg diatomic molecule

    NASA Astrophysics Data System (ADS)

    Balducci, G.; Ciccioli, A.; Gigli, G.; Kudin, L. S.

    2003-02-01

    The dissociation energy of the intermetallic molecule AuMg was for the first time determined by the Knudsen-effusion mass spectrometry technique. Partial pressures of Au(g), Mg(g), AuMg(g) and Au 2(g) species produced under equilibrium vaporization of an appropriate alloy were monitored in the temperature range 1870-2333 K. The collected data were analyzed by the second- and third-law methods for the gaseous equilibria AuMg(g)=Au(g) + Mg(g) and AuMg(g) + Au(g)=Au 2(g) + Mg(g). The selected value for the dissociation energy of AuMg at 0 K is D0∘(AuMg)= 175.4±2.7 kJ/mol.

  7. Controlling Au Photodeposition on Large ZnO Nanoparticles.

    PubMed

    Fernando, Joseph F S; Shortell, Matthew P; Noble, Christopher J; Harmer, Jeffrey R; Jaatinen, Esa A; Waclawik, Eric R

    2016-06-01

    This study investigated how to control the rate of photoreduction of metastable AuCl2(-) at the solid-solution interface of large ZnO nanoparticles (NPs) (50-100 nm size). Band-gap photoexcitation of electronic charge in ZnO by 370 nm UV light yielded Au NP deposition and the formation of ZnO-Au NP hybrids. Au NP growth was observed to be nonepitaxial, and the patterns of Au photodeposition onto ZnO NPs observed by high-resolution transmission electron microscopy were consistent with reduction of AuCl2(-) at ZnO facet edges and corner sites. Au NP photodeposition was effective in the presence of labile oleylamine ligands attached to the ZnO surface; however, when a strong-binding dodecanethiol ligand coated the surface, photodeposition was quenched. Rates of interfacial electron transfer at the ZnO-solution interface were adjusted by changing the solvent, and these rates were observed to strongly depend on the solvent's permittivity (ε) and viscosity. From measurements of electron transfer from ZnO to the organic dye toluidine blue at the ZnO-solution interface, it was confirmed that low ε solvent mixtures (ε ≈ 9.5) possessed markedly higher rates of photocatalytic interfacial electron transfer (∼3.2 × 10(4) electrons·particle(-1)·s(-1)) compared to solvent mixtures with high ε (ε = 29.9, ∼1.9 × 10(4) electrons·particle(-1)·s(-1)). Dissolved oxygen content in the solvent and the exposure time of ZnO to band-gap, near-UV photoexcitation were also identified as factors that strongly affected Au photodeposition behavior. Production of Au clusters was favored under conditions that caused electron accumulation in the ZnO-Au NP hybrid. Under conditions where electron discharge was rapid (such as in low ε solvents), AuCl2(-) precursor ions photoreduced at ZnO surfaces in less than 5 s, leading to deposition of several small, isolated ∼6 nm Au NP on the ZnO host instead. PMID:27196721

  8. Fully Crystalline Faceted Fe-Au Core-Shell Nanoparticles.

    PubMed

    Langlois, C; Benzo, P; Arenal, R; Benoit, M; Nicolai, J; Combe, N; Ponchet, A; Casanove, M J

    2015-08-12

    Fe-Au core-shell nanoparticles displaying an original polyhedral morphology have been successfully synthesized through a physical route. Analyses using transmission electron microscopy show that the Au shell forms truncated pyramids epitaxially grown on the (100) facets of the iron cubic core. The evolution of the elastic energy and strain field in the nanoparticles as a function of their geometry and composition is calculated using the finite-element method. The stability of the remarkable centered core-shell morphology experimentally observed is attributed to the weak elastic energy resulting from the low misfit at the Fe/Au (100) interface compared to the surface energy contribution. PMID:26146846

  9. Energy level alignment in Au/pentacene/PTCDA trilayer stacks

    NASA Astrophysics Data System (ADS)

    Sehati, P.; Braun, S.; Fahlman, M.

    2013-09-01

    Ultraviolet photoelectron spectroscopy is used to investigate the energy level alignment and molecular orientation at the interfaces in Au/pentacene/PTCDA trilayer stacks. We deduced a standing orientation for pentacene grown on Au while we conclude a flat lying geometry for PTCDA grown onto pentacene. We propose that the rough surface of polycrystalline Au induces the standing geometry in pentacene. It is further shown that in situ deposition of PTCDA on pentacene can influence the orientation of the surface pentacene layer, flipping part of the surface pentacene molecules into a flat lying geometry, maximizing the orbital interaction across the pentacene-PTCDA heterojunction.

  10. AuScope VLBI Project and Hobart 26-m Antenna

    NASA Technical Reports Server (NTRS)

    Lovell, Jim; Dickey, John; Reid, Brett; McCallum, Jamie; Shabala, Stas; Watson, Christopher; Ellingsen, Simon; Memin, Anthony

    2013-01-01

    This is a report on the activities carried out at the three AuScope VLBI observatories and the Hobart 26-m antenna. In 2012 the three AuScope 12-m antennas at Hobart (Hb), Katherine (Ke), and Yarragadee (Yg) completed their first full year of operations as an array. The Hobart 26-m antenna (Ho) continued to make a contribution to IVS, providing overlap with the Hb time series. In total the AuScope antennas and the Hobart 26 m observed for 146 antenna days in 2012. In this report we also briefly highlight our research activities during 2012 and our plans for 2013.

  11. The growth and enhanced catalytic performance of Au@Pd core-shell nanodendrites

    NASA Astrophysics Data System (ADS)

    Wang, Haihua; Sun, Zhenhua; Yang, Yi; Su, Dangsheng

    2012-12-01

    Au@Pd core-shell nanodendrites were synthesized by reducing H2PdCl4 with ascorbic acid onto the surface of Au polyhedra at room temperature. The Au@Pd core-shell nanodendrites consisting of a Au core and nanoporous Pd shell, exhibited plasmonic properties and higher catalytic activity in comparison with Au@Pd core-shell nanocubes.Au@Pd core-shell nanodendrites were synthesized by reducing H2PdCl4 with ascorbic acid onto the surface of Au polyhedra at room temperature. The Au@Pd core-shell nanodendrites consisting of a Au core and nanoporous Pd shell, exhibited plasmonic properties and higher catalytic activity in comparison with Au@Pd core-shell nanocubes. Electronic supplementary information (ESI) available: Experimental details, characterization and catalytic performance measurement of Au nanopolyhedra and Au@Pd core-shell nanostructures, TEM image of Au nanopolyhedra and Au@Pd core-shell nanodendrites after four cycles of the Suzuki coupling reaction, TEM and high-resolution images of a single Au@Pd core-shell nanodendrite, and XRD pattern of Au@Pd core-shell nanodendrites, UV-vis spectrum of Au@Pd nanodendrites in the range 200-400 nm, references. See DOI: 10.1039/c2nr32849f

  12. Au plasmonics in a WS{sub 2}-Au-CuInS{sub 2} photocatalyst for significantly enhanced hydrogen generation

    SciTech Connect

    Cheng, Zhongzhou; Wang, Zhenxing E-mail: hej@nanoctr.cn; Shifa, Tofik Ahmed; Wang, Fengmei; Zhan, Xueying; Xu, Kai; He, Jun E-mail: hej@nanoctr.cn; Liu, Quanlin

    2015-11-30

    Promoting the activities of photocatalysts is still the critical challenge in H{sub 2} generation area. Here, a Au plasmon enhanced photocatalyst of WS{sub 2}-Au-CuInS{sub 2} is developed by inserting Au nanoparticles between WS{sub 2} nanotubes and CuInS{sub 2} (CIS) nanoparticles. Due to the localized surface plasmonic resonance properties from Au nanoparticles, WS{sub 2}-Au-CIS shows the best performance as compared to Au-CIS, CIS, WS{sub 2}-CIS, CIS-Au, WS{sub 2}-Au, and WS{sub 2}-CIS-Au. The surface plasmonic resonance effects dramatically intensify the absorption of visible light and help to inject hot electrons into the semiconductors. Our findings open up an efficient method to optimize the type-II structures for photocatalytic water splitting.

  13. Corrigendum to “Suppression of Υ production in d+Au and Au+Au collisions at √ SNN = 200 GeV" [Phys. Lett. B 735 (2014) 127-137

    SciTech Connect

    Adamczyk, L.

    2015-04-01

    We report measurements of Υ meson production in p + p, d + Au, and Au+Au collisions using the STAR detector at RHIC. We compare the Υ yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in the rapidity range |y| < 1 in d + Au collisions of RdAu = 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R AA = 0.49 ±0.1(stat.) ±0.02(syst.) ±0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.

  14. Corrigendum to “Suppression of Υ production in d+Au and Au+Au collisions at √ SNN = 200 GeV" [Phys. Lett. B 735 (2014) 127-137

    DOE PAGESBeta

    Adamczyk, L.

    2015-04-01

    We report measurements of Υ meson production in p + p, d + Au, and Au+Au collisions using the STAR detector at RHIC. We compare the Υ yield to the measured cross section in p + p collisions in order to quantify any modifications of the yield in cold nuclear matter using d + Au data and in hot nuclear matter using Au+Au data separated into three centrality classes. Our p + p measurement is based on three times the statistics of our previous result. We obtain a nuclear modification factor for Upsilon (1S + 2S + 3S) in themore » rapidity range |y| < 1 in d + Au collisions of RdAu = 0.79 ± 0.24(stat.) ± 0.03(syst.) ± 0.10(p + p syst.). A comparison with models including shadowing and initial state parton energy loss indicates the presence of additional cold-nuclear matter suppression. Similarly, in the top 10% most-central Au + Au collisions, we measure a nuclear modification factor of R AA = 0.49 ±0.1(stat.) ±0.02(syst.) ±0.06(p + p syst.), which is a larger suppression factor than that seen in cold nuclear matter. Our results are consistent with complete suppression of excited-state Upsilon mesons in Au + Au collisions. The additional suppression in Au + Au is consistent with the level expected in model calculations that include the presence of a hot, deconfined Quark–Gluon Plasma. However, understanding the suppression seen in d + Au is still needed before any definitive statements about the nature of the suppression in Au + Au can be made.« less

  15. Transverse-energy distributions at midrapidity in p +p, d +Au, and Au +Au collisions at √sNN =62.4-200 GeV and implications for particle-production models

    NASA Astrophysics Data System (ADS)

    Adler, S. S.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Jamel, A.; Alexander, J.; Aoki, K.; Aphecetche, L.; Armendariz, R.; Aronson, S. H.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Baldisseri, A.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Bathe, S.; Batsouli, S.; Baublis, V.; Bauer, F.; Bazilevsky, A.; Belikov, S.; Bennett, R.; Berdnikov, Y.; Bjorndal, M. T.; Boissevain, J. G.; Borel, H.; Boyle, K.; Brooks, M. L.; Brown, D. S.; Bruner, N.; Bucher, D.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Burward-Hoy, J. M.; Butsyk, S.; Camard, X.; Campbell, S.; Chai, J.-S.; Chand, P.; Chang, W. C.; Chernichenko, S.; Chi, C. Y.; Chiba, J.; Chiu, M.; Choi, I. J.; Choudhury, R. K.; Chujo, T.; Cianciolo, V.; Cleven, C. R.; Cobigo, Y.; Cole, B. A.; Comets, M. P.; Constantin, P.; Csanád, M.; Csörgő, T.; Cussonneau, J. P.; Dahms, T.; Das, K.; David, G.; Deák, F.; Delagrange, H.; Denisov, A.; D'Enterria, D.; Deshpande, A.; Desmond, E. J.; Devismes, A.; Dietzsch, O.; Dion, A.; Drachenberg, J. L.; Drapier, O.; Drees, A.; Dubey, A. K.; Durum, A.; Dutta, D.; Dzhordzhadze, V.; Efremenko, Y. V.; Egdemir, J.; Enokizono, A.; En'yo, H.; Espagnon, B.; Esumi, S.; Fields, D. E.; Finck, C.; Fleuret, F.; Fokin, S. L.; Forestier, B.; Fox, B. D.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fung, S.-Y.; Gadrat, S.; Gastineau, F.; Germain, M.; Glenn, A.; Gonin, M.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gunji, T.; Gustafsson, H.-Å.; Hachiya, T.; Hadj Henni, A.; Haggerty, J. S.; Hagiwara, M. N.; Hamagaki, H.; Hansen, A. G.; Harada, H.; Hartouni, E. P.; Haruna, K.; Harvey, M.; Haslum, E.; Hasuko, K.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Heuser, J. M.; Hidas, P.; Hiejima, H.; Hill, J. C.; Hobbs, R.; Holmes, M.; Holzmann, W.; Homma, K.; Hong, B.; Hoover, A.; Horaguchi, T.; Hur, M. G.; Ichihara, T.; Iinuma, H.; Ikonnikov, V. V.; Imai, K.; Inaba, M.; Inuzuka, M.; Isenhower, D.; Isenhower, L.; Ishihara, M.; Isobe, T.; Issah, M.; Isupov, A.; Jacak, B. V.; Jia, J.; Jin, J.; Jinnouchi, O.; Johnson, B. M.; Johnson, S. C.; Joo, K. S.; Jouan, D.; Kajihara, F.; Kametani, S.; Kamihara, N.; Kaneta, M.; Kang, J. H.; Katou, K.; Kawabata, T.; Kawagishi, T.; Kazantsev, A. V.; Kelly, S.; Khachaturov, B.; Khanzadeev, A.; Kikuchi, J.; Kim, D. J.; Kim, E.; Kim, E. J.; Kim, G.-B.; Kim, H. J.; Kim, Y.-S.; Kinney, E.; Kiss, Á.; Kistenev, E.; Kiyomichi, A.; Klein-Boesing, C.; Kobayashi, H.; Kochenda, L.; Kochetkov, V.; Kohara, R.; Komkov, B.; Konno, M.; Kotchetkov, D.; Kozlov, A.; Kroon, P. J.; Kuberg, C. H.; Kunde, G. J.; Kurihara, N.; Kurita, K.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lajoie, J. G.; Lebedev, A.; Leâ Bornec, Y.; Leckey, S.; Lee, D. M.; Lee, M. K.; Leitch, M. J.; Leite, M. A. L.; Li, X. H.; Lim, H.; Litvinenko, A.; Liu, M. X.; Maguire, C. F.; Makdisi, Y. I.; Malakhov, A.; Malik, M. D.; Manko, V. I.; Mao, Y.; Martinez, G.; Masui, H.; Matathias, F.; Matsumoto, T.; McCain, M. C.; McGaughey, P. L.; Miake, Y.; Miller, T. E.; Milov, A.; Mioduszewski, S.; Mishra, G. C.; Mitchell, J. T.; Mohanty, A. K.; Morrison, D. P.; Moss, J. M.; Moukhanova, T. V.; Mukhopadhyay, D.; Muniruzzaman, M.; Murata, J.; Nagamiya, S.; Nagata, Y.; Nagle, J. L.; Naglis, M.; Nakamura, T.; Newby, J.; Nguyen, M.; Norman, B. E.; Nyanin, A. S.; Nystrand, J.; O'Brien, E.; Ogilvie, C. A.; Ohnishi, H.; Ojha, I. D.; Okada, K.; Omiwade, O. O.; Oskarsson, A.; Otterlund, I.; Oyama, K.; Ozawa, K.; Pal, D.; Palounek, A. P. T.; Pantuev, V.; Papavassiliou, V.; Park, J.; Park, W. J.; Pate, S. F.; Pei, H.; Penev, V.; Peng, J.-C.; Pereira, H.; Peresedov, V.; Peressounko, D. Yu.; Pierson, A.; Pinkenburg, C.; Pisani, R. P.; Purschke, M. L.; Purwar, A. K.; Qu, H.; Qualls, J. M.; Rak, J.; Ravinovich, I.; Read, K. F.; Reuter, M.; Reygers, K.; Riabov, V.; Riabov, Y.; Roche, G.; Romana, A.; Rosati, M.; Rosendahl, S. S. E.; Rosnet, P.; Rukoyatkin, P.; Rykov, V. L.; Ryu, S. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakai, S.; Samsonov, V.; Sanfratello, L.; Santo, R.; Sarsour, M.; Sato, H. D.; Sato, S.; Sawada, S.; Schutz, Y.; Semenov, V.; Seto, R.; Sharma, D.; Shea, T. K.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shohjoh, T.; Shoji, K.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Sim, K. S.; Singh, C. P.; Singh, V.; Skutnik, S.; Smith, W. C.; Soldatov, A.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Staley, F.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Suire, C.; Sullivan, J. P.; Sziklai, J.; Tabaru, T.; Takagi, S.; Takagui, E. M.; Taketani, A.; Tanaka, K. H.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Taranenko, A.; Tarján, P.; Thomas, T. L.; Togawa, M.; Tojo, J.; Torii, H.; Towell, R. S.; Tram, V.-N.

    2014-04-01

    Measurements of the midrapidity transverse-energy distribution, dET/dη, are presented for p +p, d +Au, and Au +Au collisions at √sNN =200 GeV and additionally for Au +Au collisions at √sNN =62.4 and 130 GeV. The dET/dη distributions are first compared with the number of nucleon participants Npart, number of binary collisions Ncoll, and number of constituent-quark participants Nqp calculated from a Glauber model based on the nuclear geometry. For Au +Au, /Npart increases with Npart, while /Nqp is approximately constant for all three energies. This indicates that the two-component ansatz, dET/dη ∝(1-x)Npart/2+xNcoll, which was used to represent ET distributions, is simply a proxy for Nqp, and that the Ncoll term does not represent a hard-scattering component in ET distributions. The dET/dη distributions of Au +Au and d +Au are then calculated from the measured p +p ET distribution using two models that both reproduce the Au +Au data. However, while the number-of-constituent-quark-participant model agrees well with the d +Au data, the additive-quark model does not.

  16. From Superatomic Au25(SR)18- to Superatomic M@Au24(SR)18q Core-shell Clusters.

    SciTech Connect

    Jiang, Deen; Dai, Sheng

    2009-01-01

    Au{sub 25}(SR){sub 18}{sup -} belongs to a new type of superatom that features an icosahedral Au{sub 13} core-shell structure and a protective layer of six RS(Au-SR){sub 2} motifs. This superatom has a magic number of 8 free electrons that fully fill the 1s and 1p levels of the electron-shell model. By applying this superatom concept to the core-substitution chemistry of Au{sub 25}(SR){sub 18}{sup -}, we first scanned the periodic table for the potential core atom M by applying a simple rule derived from the 8-electron count and then optimized the selected candidates by density functional theory calculations to create many series of M{at}Au{sub 24}(SR){sub 18}{sup q} core-shell nanoclusters. We found that 16 elements from groups 1, 2, and 10-14 of the periodic table can maintain both electronic and geometric structures of the original Au{sub 25}(SR){sub 18}{sup -} magic cluster, indicating that the electron-counting rule based on the superatom concept is powerful in predicting viable M{at}Au{sub 24}(SR){sub 18}{sup q} clusters. Our work opens up a promising area for experimental exploration.

  17. Crystal structures and magnetic properties of CsAu4Si2 and CeAu2Si2

    SciTech Connect

    Sefat, A.; Palasyuk, A.; Bud'ko, S.; Corbett, J.; Canfield, P.

    2007-12-03

    Single crystals of CeAu{sub 4}Si{sub 2} and CeAu{sub 2}Si{sub 2} have been grown out of ternary fluxes rich in Au, and the former, also by sintering the stoichiometric composition at 750 C. The single-crystal X-ray refinement result for CeAu{sub 4}Si{sub 2} is orthorhombic, Cmmm (No. 65, Z=2), different from a tetragonal result found from an X-ray powder diffraction refinement [H. Nakashima, et al., J. Alloys Compds. 424 (2006) 7]. For CeAu{sub 2}Si{sub 2}, this is the first report of the stoichiometric crystalline phase, in the known tetragonal I4/mmm structure. The anisotropic field- and temperature-dependent magnetizations, as well as specific heat and resistivity data are compared. Although both compounds have related structural packing, they present unique magnetic features. CeAu{sub 2}Si{sub 2} is a typical antiferromagnet with T{sub N} = 8.8(1) K and CeAu{sub 4}Si{sub 2} features a ferromagnetic component below T{sub c}=3.3(1) K. Both phases have effective moments close in value to that of free Ce{sup 3+}.

  18. Gold surfaces and nanoparticles are protected by Au(0)-thiyl species and are destroyed when Au(I)-thiolates form.

    PubMed

    Reimers, Jeffrey R; Ford, Michael J; Halder, Arnab; Ulstrup, Jens; Hush, Noel S

    2016-03-15

    The synthetic chemistry and spectroscopy of sulfur-protected gold surfaces and nanoparticles is analyzed, indicating that the electronic structure of the interface is Au(0)-thiyl, with Au(I)-thiolates identified as high-energy excited surface states. Density-functional theory indicates that it is the noble character of gold and nanoparticle surfaces that destabilizes Au(I)-thiolates. Bonding results from large van der Waals forces, influenced by covalent bonding induced through s-d hybridization and charge polarization effects that perturbatively mix in some Au(I)-thiolate character. A simple method for quantifying these contributions is presented, revealing that a driving force for nanoparticle growth is nobleization, minimizing Au(I)-thiolate involvement. Predictions that Brust-Schiffrin reactions involve thiolate anion intermediates are verified spectroscopically, establishing a key feature needed to understand nanoparticle growth. Mixing of preprepared Au(I) and thiolate reactants always produces Au(I)-thiolate thin films or compounds rather than monolayers. Smooth links to O, Se, Te, C, and N linker chemistry are established. PMID:26929334

  19. Visible light photoactivity of TiO2 loaded with monometallic (Au or Pt) and bimetallic (Au/Pt) nanoparticles

    NASA Astrophysics Data System (ADS)

    Gołąbiewska, Anna; Lisowski, Wojciech; Jarek, Marcin; Nowaczyk, Grzegorz; Zielińska-Jurek, Anna; Zaleska, Adriana

    2014-10-01

    TiO2 modified with monometallic (Au or Pt) and bimetallic (Au/Pt) nanoparticles have been prepared using a water-in-oil microemulsion system (water/AOT/cyclohexane) followed by calcination step. The effect of metal ratio, reducing agent type (NaBH4 or N2H4), TiO2 matrix type (P-25, ST-01, TiO-5, TiO2 nanotubes or TiO2 obtained by TIP hydrolysis) as well as calcination temperature (from 350 to 650 °C) were systematically investigated. Obtained photocatalysts were characterized by UV-vis diffuse-reflectance spectroscopy (DRS), BET surface area measurements, scanning transmission microscopy (STEM), X-ray diffraction analysis (XRD), and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity under visible light (λ > 420 nm) has been estimated in phenol degradation reaction in aqueous phase. The results showed that phenol degradation rate under visible light in the presence of TiO2 loaded with Au/Pt nanoparticles differed from 0.7 to 2.2 μmol dm-3 min-1 for samples prepared using different reducing agent. Sodium borohydride (NaBH4) favors formation of smaller Au/Pt nanoparticles and higher amount gold in Au/Pt is in the form of electronegative species (Auδ-) resulted in higher photoactivity. TiO2 obtained by TIP hydrolysis in microemulsion system seems to be the best support for Au/Pt nanoparticles from all among investigated matrix. It was also observed that enhancement of calcination temperature from 450 to 650 °C resulted in rapid drop of Au/Pt-TiO2 photoactivity under visible light due to surface area shrinkage, crystal structure change and probably change in Au/Pt nanoparticles morphology.

  20. Activated Dissociation of HCl on Au(111).

    PubMed

    Shirhatti, Pranav R; Geweke, Jan; Steinsiek, Christoph; Bartels, Christof; Rahinov, Igor; Auerbach, Daniel J; Wodtke, Alec M

    2016-04-01

    We report zero-coverage reaction probabilities (S0) for HCl dissociative adsorption on Au(111) obtained by the seeded molecular beam hot-nozzle method. For measurements at normal incidence with mean translational energies ranging from 0.94 to 2.56 eV (nozzle temperatures 296 to 1060 K), S0 increased from 6 × 10(-6) to 2 × 10(-2). S0 also increased with increasing nozzle temperature for fixed incidence energy associated with the motion normal to the surface. Accounting for the influence of the vibrational state population and translational energy distributions in the incident beam, we are able to compare the experimental results to recent theoretical predictions. These calculations, performed employing 6-D quantum dynamics on an electronically adiabatic potential energy surface obtained using density functional theory at the level of the generalized gradient approximation and the static surface approximation, severely overestimate the reaction probabilities when compared with our experimental results. We discuss some possible reasons for this large disagreement. PMID:26990513

  1. The AuScope geodetic VLBI array

    NASA Astrophysics Data System (ADS)

    Lovell, J. E. J.; McCallum, J. N.; Reid, P. B.; McCulloch, P. M.; Baynes, B. E.; Dickey, J. M.; Shabala, S. S.; Watson, C. S.; Titov, O.; Ruddick, R.; Twilley, R.; Reynolds, C.; Tingay, S. J.; Shield, P.; Adada, R.; Ellingsen, S. P.; Morgan, J. S.; Bignall, H. E.

    2013-06-01

    The AuScope geodetic Very Long Baseline Interferometry array consists of three new 12-m radio telescopes and a correlation facility in Australia. The telescopes at Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western Australia) are co-located with other space geodetic techniques including Global Navigation Satellite Systems (GNSS) and gravity infrastructure, and in the case of Yarragadee, satellite laser ranging (SLR) and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) facilities. The correlation facility is based in Perth (Western Australia). This new facility will make significant contributions to improving the densification of the International Celestial Reference Frame in the Southern Hemisphere, and subsequently enhance the International Terrestrial Reference Frame through the ability to detect and mitigate systematic error. This, combined with the simultaneous densification of the GNSS network across Australia, will enable the improved measurement of intraplate deformation across the Australian tectonic plate. In this paper, we present a description of this new infrastructure and present some initial results, including telescope performance measurements and positions of the telescopes in the International Terrestrial Reference Frame. We show that this array is already capable of achieving centimetre precision over typical long-baselines and that network and reference source systematic effects must be further improved to reach the ambitious goals of VLBI2010.

  2. Metanephrine neuroendocrine tumor marker detection by SERS using Au nanoparticle/Au film sandwich architecture.

    PubMed

    Boca, Sanda; Farcau, Cosmin; Baia, Monica; Astilean, Simion

    2016-02-01

    Neuroendocrine tumors, such as pheochromocytoma or paraganglioma, are dangerous tumors that constitute a potential threat for a large number of patients. Currently, the biochemical diagnosis of neuroendocrine tumors is based on measurement of the direct secretory products of the adrenomedullary-sympathetic system or of their metabolites, such as catecholamines or their metanephrine derivatives, from plasma or urine. The techniques used for analysis of plasma free metanephrines, i.e. high-performance liquid chromatography or high-performance liquid chromatography coupled with mass-spectrometry are technically-demanding and time consuming, which limit their availability. Here we demonstrate a simple, fast and low-cost method for detecting metanephrine by Surface Enhanced Raman Scattering (SERS). The protocol consists in using evaporation-induced self-assembly of gold (Au) nanoparticles incubated with the analyte, on planar gold films. The assembly process produces regions with a dense distribution of both inter-particle gaps and particle-film gaps. Finite-difference time-domain simulations confirm that both kinds of gaps are locations of enhanced electromagnetic fields resulting from inter-particle and particle-film plasmonic coupling, useful for SERS amplification. Metanephrine vibrational bands assignment was performed according to density functional theory calculations. Metanephrine metabolite was detected in liquid at concentration levels lower than previously reported for other similar metabolites. The obtained results demonstrate that the Au nanoparticle/Au film exhibits noticeable SERS amplification of the adsorbed metabolite and can be used in the design of efficient, stable SERS-active substrates for the detection and identification of specific tumor markers. PMID:26820563

  3. Heterostructured Au/Pd-M (M = Au, Pd, Pt) nanoparticles with compartmentalized composition, morphology, and electrocatalytic activity

    NASA Astrophysics Data System (ADS)

    Lutz, Patrick S.; Bae, In-Tae; Maye, Mathew M.

    2015-09-01

    The synthesis, processing, and galvanic exchange of three heterostructured nanoparticle systems is described. The surface accessibility and redox potential of a Au/Pd-Ag dumbbell nanoparticle, where a Au/Pd core/shell region, and a silver region make up the domains, was used to prepare the new nanostructures with controlled composition, morphology, and microstructure. Results indicate that the silver domain was particularly susceptible to galvanic displacement, and was exchanged to Au/Pd-M (M = Au, Pd, Pt). Interestingly, the dumbbell morphology remained after exchange, and the silver region was transformed to hollow, parachute, or concentric domains respectively. The morphology and microstructure change was visualized via TEM and HRTEM, and the composition changes were probed via STEM-EDS imaging and XPS. The electrocatalytic activity of the Au/Pd-M towards methanol oxidation was studied, with results indicating that the Au/Pd-Pt nanoparticles had high activity attributed to the porous nature of the platinum domains.The synthesis, processing, and galvanic exchange of three heterostructured nanoparticle systems is described. The surface accessibility and redox potential of a Au/Pd-Ag dumbbell nanoparticle, where a Au/Pd core/shell region, and a silver region make up the domains, was used to prepare the new nanostructures with controlled composition, morphology, and microstructure. Results indicate that the silver domain was particularly susceptible to galvanic displacement, and was exchanged to Au/Pd-M (M = Au, Pd, Pt). Interestingly, the dumbbell morphology remained after exchange, and the silver region was transformed to hollow, parachute, or concentric domains respectively. The morphology and microstructure change was visualized via TEM and HRTEM, and the composition changes were probed via STEM-EDS imaging and XPS. The electrocatalytic activity of the Au/Pd-M towards methanol oxidation was studied, with results indicating that the Au/Pd-Pt nanoparticles had

  4. Glass formability and the Al-Au system

    SciTech Connect

    Egami, Takeshi; Ojha, Madhusudan; Nicholson, Donald M.; Louzguine-Luzgin, Dmitri; Chen, Na; Inoue, A.

    2012-01-01

    The aluminum-gold system exhibits various features that suggest high glass formability, such as a deep eutectic, formation of icosahedral clusters in the intermetallic compound near the eutectic minimum and a strongly negative heat of mixing. However, it is very difficult to form a glass with this system. Various issues related to glass formability are discussed using the Al-Au system as a negative test-case. In particular, the atomic level pressure was calculated from first principles for the first time for Al{sub 2}Au, AlAu{sub 2} and AlAu{sub 4} intermetallic compounds. The atomic level pressure is very high in these compounds, suggesting frustrated electronic states which destabilize both crystalline and glassy phases.

  5. Assembling Bare Au Nanoparticles at Positively Charged Templates

    PubMed Central

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-01-01

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the charged-interfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits short-range in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs. PMID:27225047

  6. Efficient synthesis of Au99(SR)42 nanoclusters

    NASA Astrophysics Data System (ADS)

    Liu, Chao; Lin, Jizhi; Shi, Yangwei; Li, Gao

    2015-03-01

    We report a new synthetic protocol of Au99(SPh)42 nanoclusters with moderate efficiency (~15% yield based on HAuCl4), via a combination of the ligand-exchange and ``size-focusing'' processes. The purity of the as-prepared gold nanoclusters is characterized by matrix-assisted laser desorption ionization mass spectrometry and size exclusion chromatography.We report a new synthetic protocol of Au99(SPh)42 nanoclusters with moderate efficiency (~15% yield based on HAuCl4), via a combination of the ligand-exchange and ``size-focusing'' processes. The purity of the as-prepared gold nanoclusters is characterized by matrix-assisted laser desorption ionization mass spectrometry and size exclusion chromatography. Electronic supplementary information (ESI) available: Experimental section: the synthetic procedure of the Au99(SPh)42 nanoclusters and characterization of the Au cluster. See DOI: 10.1039/c5nr00543d

  7. Magnetic order of Au nanoparticle with clean surface

    NASA Astrophysics Data System (ADS)

    Sato, Ryuju; Ishikawa, Soichiro; Sato, Hiroyuki; Sato, Tetsuya

    2015-11-01

    Au nanoparticles, which are kept in vacuum after the preparation by gas evaporation method, show ferromagnetism even in 1.7 nm in diameter. The intrinsic magnetism is examined by detecting the disappearance of spontaneous magnetization in Au bulk prepared by heating the nanoparticles without exposure to the air. The temperature dependence of spontaneous magnetization is not monotonic and the increase in magnetization is observed after Au nanoparticles are exposed to the air. The magnetic behavior can be interpreted by the ferrimagnetic-like core-shell structure with shell thickness of 0.16±0.01 nm and magnetic moment of (1.5±0.1)×10-2 μB/Au atom, respectively.

  8. Assembling Bare Au Nanoparticles at Positively Charged Templates.

    PubMed

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-01-01

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the charged-interfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits short-range in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs. PMID:27225047

  9. Au/p-diamond ohmic contacts deposited by RF sputtering

    NASA Astrophysics Data System (ADS)

    Zhen, C. M.; Wang, X. Q.; Wu, X. C.; Liu, C. X.; Hou, D. L.

    2008-12-01

    Ohmic contacts have been formed on diamond films using a monolayer Au. Au film was deposited by radio frequency sputtering. I- V measurements show the good ohmic behavior of the contacts in the as-deposited and annealed states and the specific contact resistivity obtained by circular transmission line model was 1.27 × 10 -3 and 5.43 × 10 -4 Ω cm 2, respectively. Radio frequency sputtering makes an obvious interdiffusion between Au and diamond in the as-deposited contacts. Annealing the contact enhances the interdiffusion. X-ray photoelectron spectroscopy analyses and cross-sectional scan electron microscopy reveal the presence of an intermediate layer at the interface due to the intermixing between Au and diamond. Surface native oxide of the diamond film was effectively removed by treating the substrate film in boiling aqua regia solution.

  10. Assembling Bare Au Nanoparticles at Positively Charged Templates

    NASA Astrophysics Data System (ADS)

    Wang, Wenjie; Zhang, Honghu; Kuzmenko, Ivan; Mallapragada, Surya; Vaknin, David

    2016-05-01

    In-situ X-ray reflectivity (XRR) and grazing incidence X-ray small-angle scattering (GISAXS) reveal that unfunctionalized (bare) gold nanoparticles (AuNP) spontaneously adsorb to a cationic lipid template formed by a Langmuir monolayer of DPTAP (1,2-dihexadecanoyl-3-trimethylammonium-propane) at vapor/aqueous interfaces. Analysis of the XRR yields the electron density profile across the charged-interfaces along the surface normal showing the AuNPs assemble with vertical thickness comparable to the particle size. The GISAXS analysis indicates that the adsorbed mono-particle layer exhibits short-range in-plane correlations. By contrast, single-stranded DNA-functionalized AuNPs, while attracted to the positively charged surface (more efficiently with the addition of salt to the solution), display less in-plane regular packing compared to bare AuNPs.

  11. Dynamic features of rod-shaped Au nanoclusters

    NASA Astrophysics Data System (ADS)

    So, Woong Young; Das, Anindita; Wang, Shuxin; Zhao, Shuo; Byun, Hee Young; Lee, Dana; Kumar, Santosh; Jin, Rongchao; Peteanu, Linda A.

    2015-08-01

    Gold nanoclusters hold many potential applications such as biosensing and optics due to their emission characteristics, small size, and non-toxicity. However, their low quantum yields remain problematic for further applications, and their fluorescence mechanism is still unclear. To increase the low quantum yields, various methods have been performed: doping, tuning structures, and changing number of gold atoms. In the past, most characterizations have been performed on spherical shaped nanoclusters; in this paper, several characterizations of various rod-shaped Au nanoclusters specifically on Au25 are shown. It has been determined that the central gold atom in Au25 nano-rod is crucial in fluorescence. Furthermore, single molecule analysis of silver doped Au25 nano-rod revealed that it has more photo-stability than conjugated polymers and quantum dots.

  12. Au transport in catalyst coarsening and Si nanowire formation.

    PubMed

    Kim, B J; Tersoff, J; Kodambaka, S; Jang, Ja-Soon; Stach, E A; Ross, F M

    2014-08-13

    The motion of Au between AuSi liquid eutectic droplets, both before and during vapor-liquid-solid growth, is important in controlling tapering and diameter uniformity in Si nanowires. We measure the kinetics of coarsening of AuSi droplets on Si(001) and Si(111), quantifying the size evolution of droplets during annealing in ultrahigh vacuum using in situ transmission electron microscopy. For individual droplets, we show that coarsening kinetics are modified when disilane or oxygen is added: coarsening rates increase in the presence of disilane but decrease in oxygen. Matching droplet size measurements on Si(001) with coarsening models confirms that Au transport is driven by capillary forces and that the kinetic coefficients depend on the gas environment present. We suggest that the gas effects are qualitatively similar whether transport is attachment limited or diffusion limited. These results provide insight into manipulating nanowire morphologies for advanced device fabrication. PMID:25040757

  13. Pd versus Au as evaporated metal contacts to molecules

    SciTech Connect

    Haick, Hossam; Ghabboun, Jamal; Cahen, David

    2005-01-24

    Indirect e-beam evaporation of metal on a cooled substrate that allows making reproducible and gentle electrical contact to molecular films of organic molecules yields strikingly different results with Pd and Au. This is attributed to different growth modes of the metals, which lead to different molecule/metal interactions and to Au penetration in between the molecules. These differences can radically change the effect of the molecules on the resulting junctions.

  14. Melting curve of metals Cu, Ag and Au under pressure

    NASA Astrophysics Data System (ADS)

    Tam, Pham Dinh; Hoc, Nguyen Quang; Tinh, Bui Duc; Tan, Pham Duy

    2016-01-01

    In this paper, the dependence of the melting temperature of metals Cu, Ag and Au under pressure in the interval from 0 kbar to 40 kbar is studied by the statistical moment method (SMM). This dependence has the form of near linearity and the calculated slopes of melting curve are 3.9 for Cu, 5.7 for Ag and 6 for Au. These results are in good agreement with the experimental data.

  15. Formation, Migration, and Reactivity of Au-CO Complexes on Gold Surfaces.

    PubMed

    Wang, Jun; McEntee, Monica; Tang, Wenjie; Neurock, Matthew; Baddorf, Arthur P; Maksymovych, Petro; Yates, John T

    2016-02-10

    We report experimental as well as theoretical evidence that suggests Au-CO complex formation upon the exposure of CO to active sites (step edges and threading dislocations) on a Au(111) surface. Room-temperature scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy, transmission infrared spectroscopy, and density functional theory calculations point to Au-CO complex formation and migration. Room-temperature STM of the Au(111) surface at CO pressures in the range from 10(-8) to 10(-4) Torr (dosage up to 10(6) langmuir) indicates Au atom extraction from dislocation sites of the herringbone reconstruction, mobile Au-CO complex formation and diffusion, and Au adatom cluster formation on both elbows and step edges on the Au surface. The formation and mobility of the Au-CO complex result from the reduced Au-Au bonding at elbows and step edges leading to stronger Au-CO bonding and to the formation of a more positively charged CO (CO(δ+)) on Au. Our studies indicate that the mobile Au-CO complex is involved in the Au nanoparticle formation and reactivity, and that the positive charge on CO increases due to the stronger adsorption of CO at Au sites with lower coordination numbers. PMID:26754257

  16. Competition between Hexagonal and Tetragonal Hexabromobenzene Packing on Au(111).

    PubMed

    Huang, Han; Tan, Zhiyu; He, Yanwei; Liu, Jian; Sun, Jiatao; Zhao, Kang; Zhou, Zhenhong; Tian, Guo; Wong, Swee Liang; Wee, Andrew Thye Shen

    2016-03-22

    Low-temperature scanning tunneling microscope investigations reveal that hexabromobenzene (HBB) molecules arrange in either hexagonally closely packed (hcp) [Formula: see text] or tetragonal [Formula: see text] structure on Au(111) dependent on a small substrate temperature difference around 300 K. The underlying mechanism is investigated by density functional theory calculations, which reveal that substrate-mediated intermolecular noncovalent C-Br···Br-C attractions induce hcp HBB islands, keeping the well-known Au(111)-22×√3 reconstruction intact. Upon deposition at 330 K, HBB molecules trap freely diffusing Au adatoms to form tetragonal islands. This enhances the attraction between HBB and Au(111) but partially reduces the intermolecular C-Br···Br-C attractions, altering the Au(111)-22×√3 reconstruction. In both cases, the HBB molecule adsorbs on a bridge site, forming a ∼15° angle between the C-Br direction and [112̅]Au, indicating the site-specific molecule-substrate interactions. We show that the competition between intermolecular and molecule-substrate interactions determines molecule packing at the subnanometer scale, which will be helpful for crystal engineering, functional materials, and organic electronics. PMID:26905460

  17. Catalytic reduction of 4-nitrophenol by magnetically recoverable Au nanocatalyst.

    PubMed

    Chang, Yang-Chuang; Chen, Dong-Hwang

    2009-06-15

    A novel magnetically recoverable Au nanocatalyst was fabricated by the simple adsorption-reduction of Au(III) ions on chitosan-coated iron oxide magnetic nanocarrier. Au nanoparticles with a mean diameter of 3.14 nm were well loaded on the surface of magnetic nanocarrier because chitosan layer provided an effective driving force in the formation and stabilization of Au nanoparticles. The resultant magnetically recoverable Au nanocatalyst exhibited excellent catalytic activity to the reduction of 4-nitrophenol (4-NP) with sodium borohydride. The rate constants evaluated in terms of pseudo-first-order kinetic model increased with increasing the amount of Au nanocatalyst, decreasing the initial 4-NP concentration, and increasing the temperature. Also, the kinetic data suggested that this catalytic reaction was diffusion controlled owing to the presence of chitosan layer. In addition, catalyst reuse showed no trace of deactivation or poisoning during the catalytic and separation processes, revealing the stable nature and good catalytic ability of this nanocatalyst. PMID:19022566

  18. Spin Polarization and Quantum Spins in Au Nanoparticles

    PubMed Central

    Li, Chi-Yen; Karna, Sunil K.; Wang, Chin-Wei; Li, Wen-Hsien

    2013-01-01

    The present study focuses on investigating the magnetic properties and the critical particle size for developing sizable spontaneous magnetic moment of bare Au nanoparticles. Seven sets of bare Au nanoparticle assemblies, with diameters from 3.5 to 17.5 nm, were fabricated with the gas condensation method. Line profiles of the X-ray diffraction peaks were used to determine the mean particle diameters and size distributions of the nanoparticle assemblies. The magnetization curves M(Ha) reveal Langevin field profiles. Magnetic hysteresis was clearly revealed in the low field regime even at 300 K. Contributions to the magnetization from different size particles in the nanoparticle assemblies were considered when analyzing the M(Ha) curves. The results show that the maximum particle moment will appear in 2.4 nm Au particles. A similar result of the maximum saturation magnetization appearing in 2.3 nm Au particles is also concluded through analysis of the dependency of the saturation magnetization MP on particle size. The MP(d) curve departs significantly from the 1/d dependence, but can be described by a log-normal function. Magnetization can be barely detected for Au particles larger than 27 nm. Magnetic field induced Zeeman magnetization from the quantum confined Kubo gap opening appears in Au nanoparticles smaller than 9.5 nm in diameter. PMID:23989607

  19. Structural and dynamical properties of liquid Al-Au alloys

    NASA Astrophysics Data System (ADS)

    Peng, H. L.; Voigtmann, Th.; Kolland, G.; Kobatake, H.; Brillo, J.

    2015-11-01

    We investigate temperature- and composition-dependent structural and dynamical properties of Al-Au melts. Experiments are performed to obtain accurate density and viscosity data. The system shows a strong negative excess volume, similar to other Al-based binary alloys. We develop a molecular-dynamics (MD) model of the melt based on the embedded-atom method (EAM), gauged against the available experimental liquid-state data. A rescaling of previous EAM potentials for solid-state Au and Al improves the quantitative agreement with experimental data in the melt. In the MD simulation, the admixture of Au to Al can be interpreted as causing a local compression of the less dense Al system, driven by less soft Au-Au interactions. This local compression provides a microscopic mechanism explaining the strong negative excess volume of the melt. We further discuss the concentration dependence of self- and interdiffusion and viscosity in the MD model. Al atoms are more mobile than Au, and their increased mobility is linked to a lower viscosity of the melt.

  20. Biosupported Bimetallic Pd Au Nanocatalysts for Dechlorination of Environmental Contaminants

    SciTech Connect

    De Corte, S.; Fitts, J.; Hennebel, T.; Sabbe, T.; Bliznuk, V.; Verschuere, S.; van der Lelie, D.; Verstraete, W.; Boon, N.

    2011-08-30

    Biologically produced monometallic palladium nanoparticles (bio-Pd) have been shown to catalyze the dehalogenation of environmental contaminants, but fail to efficiently catalyze the degradation of other important recalcitrant halogenated compounds. This study represents the first report of biologically produced bimetallic Pd/Au nanoparticle catalysts. The obtained catalysts were tested for the dechlorination of diclofenac and trichloroethylene. When aqueous bivalent Pd(II) and trivalent Au(III) ions were both added to concentrations of 50 mg L{sup -1} and reduced simultaneously by Shewanella oneidensis in the presence of H{sub 2}, the resulting cell-associated bimetallic nanoparticles (bio-Pd/Au) were able to dehalogenate 78% of the initially added diclofenac after 24 h; in comparison, no dehalogenation was observed using monometallic bio-Pd or bio-Au. Other catalyst-synthesis strategies did not show improved dehalogenation of TCE and diclofenac compared with bio-Pd. Synchrotron-based X-ray diffraction, (scanning) transmission electron microscopy and energy dispersive X-ray spectroscopy indicated that the simultaneous reduction of Pd and Au supported on cells of S. oneidensis resulted in the formation of a unique bimetallic crystalline structure. This study demonstrates that the catalytic activity and functionality of possibly environmentally more benign biosupported Pd-catalysts can be improved by coprecipitation with Au.

  1. Thermal stability of Mo/Au bilayers for TES applications

    NASA Astrophysics Data System (ADS)

    Parra-Borderías, María; Fernández-Martínez, Iván; Fàbrega, Lourdes; Camón, Agustín; Gil, Oscar; González-Arrabal, Raquel; Sesé, Javier; Costa-Krämer, José Luis; Warot-Fonrose, Bénédicte; Serin, Virginie; Briones, Fernando

    2012-09-01

    Mo/Au bilayers are among the most suitable materials to be used as transition-edge sensors (TES) in cryogenic microcalorimeters and bolometers, developed, among other fields, for space missions. For this purpose the thermal stability of TES at temperatures below 150 °C is a critical issue. We report on the dependence of functional properties (superconducting critical temperature, residual resistance and α) as well as on microstructure, chemical composition and interface quality for optimized high quality Mo/Au bilayers on annealing temperature and time. Data show that the functional properties of the bilayers remain stable at T < 150 °C, but changes in microstructure, interface quality and functional properties were observed for layers heated at T ≥ 200 °C. Microstructural and chemical composition data suggest that the measured changes in residual resistance ratio (RRR) and TC at T ≥ 200 °C are mainly due to an increase in the average Au grain size and to Au migration along the Mo grain boundaries at the Au/Mo interface. A way to stabilize the functional properties of the Mo/Au bilayers against temperature enhancements is proposed.

  2. Hohlraum Te Inferred from Au L-Shell Emission

    NASA Astrophysics Data System (ADS)

    Regan, S. P.; Epstein, R.; Meyerhofer, D. D.; Sangster, T. C.; May, M. J.; Schneider, M. B.; Barrios, M. A.; Moody, J. D.; Baker, K. L.; Berzak Hopkins, L.; Brown, G. V.; Callahan, D.; Doeppner, T.; Fournier, K. B.; Hinkel, D. E.; Jones, O. S.; Kauffman, R.; Khan, S.; Kilkenny, J. D.; Landen, O. L.; Liedahl, D. A.; Nagel, S. R.; Ross, J. S.; Smalyuk, V. A.

    2014-10-01

    Laser-ablation plasmas created at the inner wall of the hohlraum (Au bubble) and at the laser entrance hole (LEH) radiate L-shell emission from Ne-like to Co-like charge states of Au. A 1-D spatially resolved and time-integrated spectrum in the 6- to 16-keV range with E/d E = 100 to 300 is recorded along the axis of the hohlraum. The Au L-shell spectral line shapes of the 2p3 / 2 - 3 s , 2p3 / 2 - 3d5 / 2 , and 2p1 / 2 - 3d3 / 2 transitions are analyzed using an atomic physics code to infer the Te of the radiating plasma. Preliminary results indicate the Au LEH plasma of a near-vacuum hohlraum has an inferred Te of 5 to 6 keV, while a gas-filled hohlraum has a significantly lower Te. A comparison of the Au L-shell spectra and the Te sensitivity will be presented, along with the plan to measure the L-shell emission from the Au bubble. This material is based upon work supported by the Department Of Energy National Nuclear Security Administration under Award Number DE-NA0001944. Part of this work was performed under the auspices of the U.S. Department of Energy by LLNL under Contract DE-AC52-07NA27344.

  3. Electric fields and chiral magnetic effect in Cu + Au collisions

    NASA Astrophysics Data System (ADS)

    Deng, Wei-Tian; Huang, Xu-Guang

    2015-03-01

    The non-central Cu + Au collisions can create strong out-of-plane magnetic fields and in-plane electric fields. By using the HIJING model, we study the general properties of the electromagnetic fields in Cu + Au collisions at 200 GeV and their impacts on the charge-dependent two-particle correlator γq1q2 = < cos ⁡ (ϕ1 +ϕ2 - 2ψRP) > (see main text for definition) which was used for the detection of the chiral magnetic effect (CME). Compared with Au + Au collisions, we find that the in-plane electric fields in Cu + Au collisions can strongly suppress the two-particle correlator or even reverse its sign if the lifetime of the electric fields is long. Combining with the expectation that if γq1q2 is induced by elliptic-flow driven effects we would not see such strong suppression or reversion, our results suggest to use Cu + Au collisions to test CME and understand the mechanisms that underlie γq1q2.

  4. Synthesis of hybrid CdS-Au colloidal nanostructures.

    PubMed

    Saunders, Aaron E; Popov, Inna; Banin, Uri

    2006-12-21

    We explore the growth mechanism of gold nanocrystals onto preformed cadmium sulfide nanorods to form hybrid metal nanocrystal/semiconductor nanorod colloids. By manipulating the growth conditions, it is possible to obtain nanostructures exhibiting Au nanocrystal growth at only one nanorod tip, at both tips, or at multiple locations along the nanorod surface. Under anaerobic conditions, Au growth occurs only at one tip of the nanorods, producing asymmetric structures. In contrast, the presence of oxygen and trace amounts of water during the reaction promotes etching of the nanorod surface, providing additional sites for metal deposition. Three growth stages are observed when Au growth is performed under air: (1) Au nanocrystal formation at both nanorod tips, (2) growth onto defect sites on the nanorod surface, and finally (3) a ripening process in which one nanocrystal tip grows at the expense of the other particles present on the nanorod. Analysis of the hybrid nanostructures by high-resolution TEM shows that there is no preferred orientation between the Au nanocrystal and the CdS nanorod, indicating that growth is nonepitaxial. The optical signatures of the nanocrystals and the nanorods (i.e., the surface plasmon and first exciton transition peaks, respectively) are spectrally distinct, allowing the different stages of the growth process to be easily monitored. The initial CdS nanorods exhibit band gap and trap state emission, both of which are quenched during Au growth. PMID:17165989

  5. DRIFTS-QMS study of room temperature CO oxidation on Au/SiO2 catalyst: nature and role of different Au species

    SciTech Connect

    Wu, Zili; Zhou, Shenghu; Zhu, Haoguo; Dai, Sheng; Overbury, Steven {Steve} H

    2009-01-01

    The nature and role of different Au species on a Au/SiO2 catalyst in room temperature (rt) CO oxidation have been studied by operando diffuse reflectance infrared spectroscopy (DRIFT) coupled with quadruple mass spectrometry (QMS). It has shown that different pretreatments (oxidative and reductive) of Au/SiO2 have significant effect on the nature of Au species and thus the CO oxidation performance. High temperature (500 C) O2-treatment leads to cationic Au species which is inactive for rt CO oxidation. Reductive treatment (either H2 or CO) results in metallic Au species that are immediately active for rt CO oxidation. Furthermore, CO oxidation activity is found in good correlation with the reduction degree of Au species, a clear indication of the essential role of metallic Au species played in rt CO oxidation. The accompanying slight deactivation with the oxidation of metallic Au species on reductively treated Au/SiO2 in CO oxidation suggests that cationic Au species may play a negative role in rt CO oxidation. The effect of water in rt CO oxidation on Au/SiO2 was also investigated. Two positive roles played by water in CO oxidation have been identified: activation of O2 and reduction of cationic Au species.

  6. Surface segregation phenomena in extended and nanoparticle surfaces of Cu-Au alloys

    NASA Astrophysics Data System (ADS)

    Li, Jonathan; Wang, Guofeng; Zhou, Guangwen

    2016-07-01

    Using density functional theory (DFT) and Monte Carlo (MC) simulations, we studied the surface segregation phenomena of Au atoms in the extended and nanoparticle surfaces of Cu-Au alloys. Our MC simulations predicted significant Au enrichment in the outermost layer of (111) and (100) extended surfaces, and Au enrichment in the two outermost layers of (110) extended surfaces. The equilibrium Cu-Au nanoparticles were predicted to develop into an Au-enriched shell structure, where Au atoms preferably segregate to the (100) facets while Cu atoms are mainly located on the (111) facet of the nanoparticles. Our simulation predictions agree with experimental measurements.

  7. Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au +Au Collisions at RHIC

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Bouchet, J.; Brandenburg, J. D.; Brandin, A. V.; Bunzarov, I.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Chakaberia, I.; Chaloupka, P.; Chang, Z.; Chatterjee, A.; Chattopadhyay, S.; Chen, J. H.; Chen, X.; Cheng, J.; Cherney, M.; Christie, W.; Contin, G.; Crawford, H. J.; Das, S.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; di Ruzza, B.; Didenko, L.; Dilks, C.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Eppley, G.; Esha, R.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Fisyak, Y.; Flores, C. E.; Fulek, L.; Gagliardi, C. A.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, S.; Gupta, A.; Guryn, W.; Hamad, A. I.; Hamed, A.; Haque, R.; Harris, J. W.; He, L.; Heppelmann, S.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Horvat, S.; Huang, T.; Huang, X.; Huang, B.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jentsch, A.; Jia, J.; Jiang, K.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Khan, Z. H.; Kikoła, D. P.; Kisel, I.; Kisiel, A.; Kochenda, L.; Koetke, D. D.; Kosarzewski, L. K.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kumar, L.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, X.; Li, C.; Li, X.; Li, Y.; Li, W.; Lin, T.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, R.; Ma, G. L.; Ma, Y. G.; Ma, L.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Matis, H. S.; McDonald, D.; McKinzie, S.; Meehan, K.; Mei, J. C.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nigmatkulov, G.; Niida, T.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Okorokov, V. A.; Olvitt, D.; Page, B. S.; Pak, R.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Pluta, J.; Poniatowska, K.; Porter, J.; Posik, M.; Poskanzer, A. M.; Pruthi, N. K.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, S.; Raniwala, R.; Ray, R. L.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, A.; Sharma, B.; Sharma, M. K.; Shen, W. Q.; Shi, Z.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, N.; Smirnov, D.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Summa, B.; Sun, Z.; Sun, X. M.; Sun, Y.; Surrow, B.; Svirida, D. N.; Tang, Z.; Tang, A. H.; Tarnowsky, T.; Tawfik, A.; Thäder, J.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Todoroki, T.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Tripathy, S. K.; Tsai, O. D.; Ullrich, T.; Underwood, D. G.; Upsal, I.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, F.; Wang, G.; Wang, J. S.; Wang, H.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xin, K.; Xu, Y. F.; Xu, Q. H.; Xu, N.; Xu, H.; Xu, Z.; Xu, J.; Yang, S.; Yang, Y.; Yang, Y.; Yang, C.; Yang, Y.; Yang, Q.; Ye, Z.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, X. P.; Zhang, Y.; Zhang, J.; Zhang, J.; Zhang, S.; Zhang, S.; Zhang, Z.; Zhang, J. B.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2016-03-01

    We present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au +Au collisions for energies ranging from √{sN N }=7.7 to 200 GeV. The third harmonic v32{2 }=⟨cos 3 (ϕ1-ϕ2)⟩ , where ϕ1-ϕ2 is the angular difference in azimuth, is studied as a function of the pseudorapidity difference between particle pairs Δ η =η1-η2 . Nonzero v32{2 } is directly related to the previously observed large-Δ η narrow-Δ ϕ ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity quark gluon plasma phase. For sufficiently central collisions, v32{2 } persist down to an energy of 7.7 GeV, suggesting that quark gluon plasma may be created even in these low energy collisions. In peripheral collisions at these low energies, however, v32{2 } is consistent with zero. When scaled by the pseudorapidity density of charged-particle multiplicity per participating nucleon pair, v32{2 } for central collisions shows a minimum near √{sN N }=20 GeV .

  8. Azimuthal anisotophy in U + U and Au + Au collisions at RHIC

    SciTech Connect

    Adamczyk, L.

    2015-11-24

    Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2} and v2{4}, for charged hadrons from U+U collisions at √SNN = 193 GeV and Au+Au collisions at √SNN = 200 GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v2{2} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. As a result, we also show that v2 vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.

  9. Measurement of Direct Photons in Ultra-Relativistic Au+Au Collisions

    NASA Astrophysics Data System (ADS)

    Gong, Haijiang

    Direct photons provide a tool to study the different stages of a heavy ion collision, especially the formation of the quark-gluon-plasma (QGP), without being influenced by the strong reaction and hadronization processes. The yield of direct photons can be determined from the inclusive photon yield and the photon yield from hadronic decays. At low pT, where a significant fraction of direct photon is expected to come from the thermalized medium of deconfined quarks and gluons and interacting hadrons, the measurement is very challenging. These so-called thermal photons carry information about the initial temperature of the medium. We present a new analysis technique that was developed to improve direct photon production measurement in the low and medium pT range. The technique was applied to the PHENIX Run4 Au+Au sqrt(sNN)=200GeV/c collisions dataset. It uses strict particle identification (PID) in the Electromagnetic Calorimeter (EMCal) and a charged particle veto to extract a clean photon signal. These photons are then tagged with EMCal photon candidates with loose PID cuts, which can be reconstructed with high efficiency, to determine the fraction of photons originating from neutral pion decays. Most systematic uncertainties and detector effects cancel in this method. The results are compared with recent PHENIX direct photon measurement through external conversion method and theoretical calculation predicting thermal photon production.

  10. Phospholipid Encapsulated AuNR@Ag/Au Nanosphere SERS Tags with Environmental Stimulus Responsive Signal Property.

    PubMed

    Su, Xueming; Wang, Yunqing; Wang, Wenhai; Sun, Kaoxiang; Chen, Lingxin

    2016-04-27

    Surface-enhanced Raman scattering (SERS) tags draw much attention due to the ultrasensitivity and multiplex labeling capability. Recently, a new kind of SERS tags was rationally designed by encapsulating metal nanoparticles with phospholipid bilayers, showing great potential in theranostics. The lipid bilayer coating confers biocompatibility and versatility to changing surface chemistry of the tag; however, its "soft" feature may influence SERS signal stability, which is rarely investigated. Herein, we prepared phospholipid-coated AuNR@Ag/Au nanosphere SERS tags by using three different kinds of Raman reporters, i.e., thio-containing 4-nitrothiophenol (NT), nitrogen-containing hydrophobic chromophore cyanine 7 monoacid (Cy7), and alkyl chain-chromophore conjugate 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine (DiD). It was found that signal responses were different upon additional stimulation which the tags may encounter in theranostic applications including the presence of detergent Triton X-100, lipid membrane, and photothermal treatment. Living-cell imaging also showed signal changing distinction. The different SERS signal performances were attributed to the different Raman reporter releasing behaviors from the tags. This work revealed that Raman reporter structure determined signal stability of lipid-coated SERS tags, providing guidance for the design of stimulus responsive tags. Moreover, it also implied the potential of SERS technique for real time drug release study of lipid based nanomedicine. PMID:27052206

  11. Azimuthal anisotophy in U + U and Au + Au collisions at RHIC

    DOE PAGESBeta

    Adamczyk, L.

    2015-11-24

    Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2{2} and v2{4}, for charged hadrons from U+U collisions at √SNN = 193 GeV and Au+Au collisions at √SNN = 200 GeV. Nearly fully overlapping collisions are selected based on the energy deposited by spectators in zero degree calorimeters (ZDCs). Within this sample, the observed dependence of v2{2} on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. As a result, we alsomore » show that v2 vs multiplicity can be better described by models, such as gluon saturation or quark participant models, that eliminate the dependence of the multiplicity on the number of binary nucleon-nucleon collisions.« less

  12. Thermal description of particle production in Au-Au collisions at RHIC energies (STAR)

    NASA Astrophysics Data System (ADS)

    Tawfik, A.; Abbas, E.

    2015-07-01

    The hadron ratios measured in central Au-Au collisions are analysed by means of Hadron Resonance Gas (HRG) model over a wide range of nucleon-nucleon center-of-mass energies, √ s NN = 7.7-200 GeV as offered by the RHIC Beam Energy Scan I (BES-I) (STAR Collaboration). The temperature and baryon chemical potential are deduced from fits of experimental ratios to thermal model calculations assuming chemical equilibrium. We find that the resulting freeze-out parameters using single hard-core value and point-like constituents of HRG are identical. This implies that the excluded-volume comes up with no effect on the extracted parameters. We compare the results with other studies and with the lattice QCD calculations. Various freeze-out conditions are confronted with the resulting data set. The effect of including new resonances is also analysed. At vanishing chemical potential, a limiting temperature was estimated, T lim = 158.5 ± 3 MeV.

  13. Scaling properties of proton and antiproton production in sqrt[s(NN)]=200 GeV Au+Au collisions.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, G; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, L D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; Van Hecke, H W; Velkovska, J; Velkovsky, M; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zolin, L

    2003-10-24

    We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at sqrt[s(NN)]=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5Au+Au, p+p, and e(+)e(-) collisions. This enhancement is limited to p(T)<5 GeV/c as deduced from the ratio of charged hadrons to pi(0) measured in the range 1.5

  14. Charged-Particle Pseudorapidity Density Distributions from Au+Au Collisions at (sNN) = 130 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Barton, D. S.; Betts, R. R.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Decowski, M. P.; Garcia, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hołyński, R.; Holzman, B.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Lin, W. T.; Manly, S.; McLeod, D.; Michałowski, J.; Mignerey, A. C.; Mülmenstädt, J.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sarin, P.; Sawicki, P.; Skulski, W.; Steadman, S. G.; Steinberg, P.; Stephans, G. S.; Stodulski, M.; Sukhanov, A.; Tang, J.-L.; Teng, R.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wadsworth, B.; Wolfs, F. L.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2001-09-01

    The charged-particle pseudorapidity density dNch/dη has been measured for Au+Au collisions at (sNN) = 130 GeV at RHIC, using the PHOBOS apparatus. The total number of charged particles produced for the 3% most-central Au+Au collisions for \\|η\\|<=5.4 is found to be 4200+/-470. The evolution of dNch/dη with centrality is discussed, and compared to model calculations and to data from proton-induced collisions. The data show an enhancement in charged-particle production at midrapidity, while in the fragmentation regions, the results are consistent with expectations from pp and pA scattering.

  15. Centrality and collision system dependence of antiproton production from p+A to Au+Au collisions at AGS energies

    NASA Technical Reports Server (NTRS)

    Sako, H.; Ahle, L.; Akiba, Y.; Ashktorab, K.; Baker, M. D.; Beavis, D.; Britt, H. C.; Chang, J.; Chasman, C.; Chen, Z.; Chu, Y. Y.; Cianciolo, V.; Cole, B. A.; Crawford, H. J.; Cumming, J. B.; Debbe, R.; Dunlop, J. C.; Eldredge, W.; Engelage, J.; Fung, S.-Y.

    1997-01-01

    Antiproton production in heavy ion collisions reflects subtle interplay between initial production and absorption by nucleons. Because the AGS energies (10--20 A(center-dot)GeV/c) are close to the antiproton production threshold, antiproton may be sensitive to cooperative processes such as QGP and hadronic multi-step processes. On the other hand, antiproton has been proposed as a probe of baryon density due to large N(anti N) annihilation cross sections. Cascade models predict the maximum baryon density reaches about 10 times the normal nucleus density in central Au+Au collisions, where the strong antiproton absorption is expected. In this paper, the authors show systematic studies of antiproton production from p+A to Au+Au collisions.

  16. Au(n)Hg(m) clusters: mercury aurides, gold amalgams, or van der Waals aggregates?

    PubMed

    Zaleski-Ejgierd, Patryk; Pyykkö, Pekka

    2009-11-12

    The class of bimetallic clusters, Au(n)M(m) (M = Zn, Cd, Hg), is calculated at the ab initio level using the DFT, RI-MP2, and CCSD(T) methods. For the triatomic Au2M (M = Zn, Cd), the auride-type linear Au-M-Au structures are preferred; for Au2Hg, the linear Au-Au-Hg "amalgam" is preferred. The mixed cation [HgAuHg]+, an analog of the known solid-state species Hg32+, is predicted. For larger Au(n)Hg(m) clusters, the results are similar to the isoelectronic Au(n)M- anions. Several local minima and transition states are identified. All are found to be planar. PMID:19228004

  17. Au-Sn SLID Bonding: A Reliable HT Interconnect and Die Attach Technology

    NASA Astrophysics Data System (ADS)

    Tollefsen, Torleif André; Larsson, Andreas; Taklo, Maaike Margrete Visser; Neels, Antonia; Maeder, Xavier; Høydalsvik, Kristin; Breiby, Dag W.; Aasmundtveit, Knut

    2013-04-01

    Au-Sn solid-liquid interdiffusion (SLID) bonding is an established reliable high temperature (HT) die attach and interconnect technology. This article presents the life cycle of an optimized HT Au-Sn SLID bond, from fabrication, via thermal treatment, to mechanical rupture. The layered structure of a strong and uniform virgin bond was identified by X-ray diffraction to be Au/ζ (Au0.85Sn0.15)/Au. During HT exposure, it was transformed to Au/β (Au1.8Sn0.2)/Au. After HT exposure, the die shear strength was reduced by 50 pct, from 14 Pa to 70 MPa, which is still remarkably high. Fractographic studies revealed a change in fracture mode; it was changed from a combination of adhesive Au/Ni and cohesive SiC fracture to a cohesive β-phase fracture. Design rules for high quality Au-Sn SLID bonds are given.

  18. Azimuthally sensitive hanbury brown-twiss interferometry in Au + Au collisions sqrt S sub NN = 200 GeV

    SciTech Connect

    Adams, J.; Adler, C.; Aggarwal, M.M.; Ahammed, Z.; Amonett, J.; Anderson, B.D.; Arkhipkin, D.; Averichev, G.S.; Badyal, S.K.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bezverkhny, B.I.; Bhardwaj, S.; Bhati, A.K.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Botje, M.; Boucham, A.; Brandin, A.; Bravar, A.; Cadman, R.V.; Cai, X.Z.; Caines, H.; Calderon de la Barca Sanchez, M.; Carroll, J.; Castillo, J.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, H.F.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Cramer, J.G.; Crawford, H.J.; Das, D.; Das, S.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Dong, W.J.; Dong, X.; Draper, J.E.; Du, F.; Dubey, A.K.; Dunin, V.B.; Dunlop, J.C.; Dutta Majumdar, M.R.; Eckardt, V.; Efimov, L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Filip, P.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Gagunashvili, N.; Gans, J.; Gaudichet, L.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J.E.; Grachov, O.; Grebenyuk, O.; Gronstal, S.; Grosnick, D.; Guertin, S.M.; Gupta, A.; Gutierrez, T.D.; Hallman, T.J.; Hamed, A.; Hardtke, D.; Harris, J.W.; Heinz, M.; Henry, T.W.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Huang, L.S.; Hughes, E.; Humanic, T.J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Jiang, H.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kabana, S.; Kaplan, M.; Keane, D.; Khodyrev, V.Yu.; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Koetke, D.D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, V.I.; Kravtsov, P.; Krueger, K.; Kuhn, C.; Kulikov, A.I.; Kumar, A.; Kunde, G.J.; Kunz, C.L.; Kutuev, R.Kh.; Kuznetsov, A.A.; Lamont, M.A.C.; et al.

    2004-06-30

    We present the results of a systematic study of the shape of the pion distribution in coordinate space at freeze-out in Au+Au collisions at RHIC using two-pion Hanbury Brown-Twiss (HBT) interferometry. Oscillations of the extracted HBT radii vs. emission angle indicate sources elongated perpendicular to the reaction plane. The results indicate that the pressure and expansion time of the collision system are not sufficient to completely quench its initial shape.

  19. Au - Be/Ru/Au multilayer metallization as a stable ohmic contact scheme to p-type InP

    NASA Astrophysics Data System (ADS)

    Malina, V.; Moro, L.; Micheli, V.; Mojzes, I.

    1996-07-01

    An attempt has been made to improve the electrical and metallurgical stability of Au - Be alloyed contacts to moderately doped p-type InP by minimizing the thickness of the Au - Be contact layer and using an Ru layer as a new, more effective diffusion barrier between the Au - Be and a thick Au top layer. It was found that the Au - Be contact layer only 40 - 50 nm thick is sufficient to give excellent ohmic contacts with specific contact resistance values as low as 0268-1242/11/7/025/img6 and 0268-1242/11/7/025/img7 (for 0268-1242/11/7/025/img8 and 0268-1242/11/7/025/img9 respectively). When subjected to an aging test at 0268-1242/11/7/025/img10 for 50 h in 0268-1242/11/7/025/img11 gas, the 50 nm Au - Be/50 nm Ru/300 nm Au contacts alloyed at an optimum temperature of about 0268-1242/11/7/025/img12 exhibit good thermal stability and no substantial increase in the specific contact resistance. The remarkable metallurgical stability of such contacts was confirmed by secondary neutral mass spectroscopy (SNMS) in-depth profile measurements. A comparison with the previously investigated diffusion barrier metals (such as Cr, Ti, Pt, etc) shows that the Ru layer is a much better barrier against the migration of Au into the InP substrate and, at the same time, it suppresses the out-diffusion of In and P from the semiconductor.

  20. Λ Λ Correlation Function in Au +Au Collisions at √{sN N }=200 GeV

    NASA Astrophysics Data System (ADS)

    Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Alford, J.; Anson, C. D.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Averichev, G. S.; Banerjee, A.; Beavis, D. R.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bordyuzhin, I. G.; Borowski, W.; Bouchet, J.; Brandin, A. V.; Brovko, S. G.; Bültmann, S.; Bunzarov, I.; Burton, T. P.; Butterworth, J.; Caines, H.; Calderón de la Barca Sánchez, M.; Campbell, J. M.; Cebra, D.; Cendejas, R.; Cervantes, M. C.; Chaloupka, P.; Chang, Z.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, L.; Cheng, J.; Cherney, M.; Chikanian, A.; Christie, W.; Chwastowski, J.; Codrington, M. J. M.; Contin, G.; Cramer, J. G.; Crawford, H. J.; Cui, X.; Das, S.; Davila Leyva, A.; De Silva, L. C.; Debbe, R. R.; Dedovich, T. G.; Deng, J.; Derevschikov, A. A.; Derradi de Souza, R.; di Ruzza, B.; Didenko, L.; Dilks, C.; Ding, F.; Djawotho, P.; Dong, X.; Drachenberg, J. L.; Draper, J. E.; Du, C. M.; Dunkelberger, L. E.; Dunlop, J. C.; Efimov, L. G.; Engelage, J.; Engle, K. S.; Eppley, G.; Eun, L.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Fedorisin, J.; Filip, P.; Fisyak, Y.; Flores, C. E.; Gagliardi, C. A.; Gangadharan, D. R.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Gliske, S.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; Guryn, W.; Haag, B.; Hamed, A.; Han, L.-X.; Haque, R.; Harris, J. W.; Heppelmann, S.; Hirsch, A.; Hoffmann, G. W.; Hofman, D. J.; Horvat, S.; Huang, B.; Huang, H. Z.; Huang, X.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Judd, E. G.; Kabana, S.; Kalinkin, D.; Kang, K.; Kauder, K.; Ke, H. W.; Keane, D.; Kechechyan, A.; Kesich, A.; Khan, Z. H.; Kikola, D. P.; Kisel, I.; Kisiel, A.; Koetke, D. D.; Kollegger, T.; Konzer, J.; Koralt, I.; Kosarzewski, L. K.; Kotchenda, L.; Kraishan, A. F.; Kravtsov, P.; Krueger, K.; Kulakov, I.; Kumar, L.; Kycia, R. A.; Lamont, M. A. C.; Landgraf, J. M.; Landry, K. D.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, J. H.; Li, C.; Li, W.; Li, X.; Li, X.; Li, Y.; Li, Z. M.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Ma, G. L.; Ma, Y. G.; Mahapatra, D. P.; Majka, R.; Margetis, S.; Markert, C.; Masui, H.; Matis, H. S.; McDonald, D.; McShane, T. S.; Minaev, N. G.; Mioduszewski, S.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nasim, Md.; Nayak, T. K.; Nelson, J. M.; Nigmatkulov, G.; Nogach, L. V.; Noh, S. Y.; Novak, J.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Oh, K.; Ohlson, A.; Okorokov, V.; Oldag, E. W.; Olvitt, D. L.; Page, B. S.; Pan, Y. X.; Pandit, Y.; Panebratsev, Y.; Pawlak, T.; Pawlik, B.; Pei, H.; Perkins, C.; Pile, P.; Planinic, M.; Pluta, J.; Poljak, N.; Poniatowska, K.; Porter, J.; Poskanzer, A. M.; Pruthi, N. K.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Raniwala, R.; Raniwala, S.; Ray, R. L.; Riley, C. K.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Ross, J. F.; Roy, A.; Ruan, L.; Rusnak, J.; Rusnakova, O.; Sahoo, N. R.; Sahu, P. K.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sangaline, E.; Sarkar, A.; Schambach, J.; Scharenberg, R. P.; Schmah, A. M.; Schmidke, W. B.; Schmitz, N.; Seger, J.; Seyboth, P.; Shah, N.; Shahaliev, E.; Shanmuganathan, P. V.; Shao, M.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shou, Q. Y.; Sichtermann, E. P.; Simko, M.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solanki, D.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stevens, J. R.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sumbera, M.; Sun, X.; Sun, X. M.; Sun, Y.; Sun, Z.; Surrow, B.; Svirida, D. N.; Symons, T. J. M.; Szelezniak, M. A.; Takahashi, J.; Tang, A. H.; Tang, Z.; Tarnowsky, T.; Thomas, J. H.; Timmins, A. R.; Tlusty, D.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tribedy, P.; Trzeciak, B. A.; Tsai, O. D.; Turnau, J.; Ullrich, T.; Underwood, D. G.; Van Buren, G.; van Nieuwenhuizen, G.; Vandenbroucke, M.; Vanfossen, J. A.; Varma, R.; Vasconcelos, G. M. S.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Viyogi, Y. P.; Vokal, S.; Vossen, A.; Wada, M.; Wang, F.; Wang, G.; Wang, H.; Wang, J. S.; Wang, X. L.; Wang, Y.; Wang, Y.; Webb, G.; Webb, J. C.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y. F.; Xiao, Z.; Xie, W.; Xin, K.; Xu, H.; Xu, J.; Xu, N.; Xu, Q. H.; Xu, Y.; Xu, Z.; Yan, W.; Yang, C.; Yang, Y.; Yang, Y.; Ye, Z.; Yepes, P.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, J. B.; Zhang, J. L.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, Z. P.; Zhao, F.; Zhao, J.; Zhong, C.; Zhu, X.; Zhu, Y. H.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

    2015-01-01

    We present Λ Λ correlation measurements in heavy-ion collisions for Au +Au collisions at √{sN N }=200 GeV using the STAR experiment at the Relativistic Heavy-Ion Collider. The Lednický-Lyuboshitz analytical model has been used to fit the data to obtain a source size, a scattering length and an effective range. Implications of the measurement of the Λ Λ correlation function and interaction parameters for dihyperon searches are discussed.

  1. Two-Pion Correlations in Au+Au Collisions at 10.8GeV/{ital c} per Nucleon

    SciTech Connect

    David, G.; Ludlam, T.; McCorkle, S.; OBrien, E.; Woody, C.; Herrmann, N.; Cole, J.; Drigert, M.; Barrette, J.; Gilbert, S.; Lacasse, R.; Mark, S.; Rosati, M.; Wang, G.; Bersch, R.; Braun-Munzinger, P.; Chang, W.; Dee, J.; Hemmick, T.; Hong, B.; Jiang, C.; Johnson, S.; Kwon, Y.; Miskowiec, D.; Panitkin, S.; Piazza, T.; Pollack, M.; Rao, M.; Sedykh, S.; Stachel, J.; Trzaska, M.; Vongpaseuth, T.; Wessels, J.; Xu, N.; Zhang, Y.; Zou, C.; Cleland, W.; Sonnadara, U.; Voloshin, S.; Dietzsch, O.; daSilva, N.; Takagui, E.; Bellwied, R.; Bennett, S.; Cormier, T.; Hall, J.; Lukaszew, A.; Li, Q.; Matheus, R.; Pruneau, C.

    1997-04-01

    Two-particle correlation functions for positive and negative pions have been measured in Au+Au collisions at 10.8GeV/{ital c} per nucleon. The data were analyzed using one- and three-dimensional correlation functions. From the results of the three-dimensional fit the phase space density of pions was calculated. It is consistent with local thermal equilibrium. {copyright} {ital 1997} {ital The American Physical Society}

  2. Facile Synthesis of Au Nanoparticles Embedded in an Ultrathin Hollow Graphene Nanoshell with Robust Catalytic Performance.

    PubMed

    Liu, Hongyang; Wang, Jia; Feng, Zhenbao; Lin, Yangming; Zhang, Liyun; Su, Dangsheng

    2015-10-01

    Au nanoparticles (NPs) uniformly embedded into an ultrathin hollow graphene nanoshell (Au@HGN) are synthesized using a facile template-based procedure. The obtained Au@HGN catalyst exhibits robust and stable catalytic performance in the reduction of 4-nitrophenol to 4-aminophenol, compared with that of traditional Au/TiO2 and previously reported Au- and Ag-based catalysts. PMID:26280245

  3. Effect of Au nano-particle aggregation on the deactivation of the AuCl3/AC catalyst for acetylene hydrochlorination.

    PubMed

    Dai, Bin; Wang, Qinqin; Yu, Feng; Zhu, Mingyuan

    2015-01-01

    A detailed study of the valence state and distribution of the AuCl3/AC catalyst during the acetylene hydrochlorination deactivation process is described and discussed. Temperature-programmed reduction and X-ray photoelectron spectral analysis indicate that the active Au(3+) reduction to metallic Au(0) is one reason for the deactivation of AuCl3/AC catalyst. Transmission electron microscopy characterization demonstrated that the particle size of Au nano-particles increases with increasing reaction time. The results indicated that metallic Au(0) exhibits considerable catalytic activity and that Au nano-particle aggregation may be another reason for the AuCl3/AC catalytic activity in acetylene hydrochlorination. PMID:25994222

  4. Effect of Au nano-particle aggregation on the deactivation of the AuCl3/AC catalyst for acetylene hydrochlorination

    PubMed Central

    Dai, Bin; Wang, Qinqin; Yu, Feng; Zhu, Mingyuan

    2015-01-01

    A detailed study of the valence state and distribution of the AuCl3/AC catalyst during the acetylene hydrochlorination deactivation process is described and discussed. Temperature-programmed reduction and X-ray photoelectron spectral analysis indicate that the active Au3+ reduction to metallic Au0 is one reason for the deactivation of AuCl3/AC catalyst. Transmission electron microscopy characterization demonstrated that the particle size of Au nano-particles increases with increasing reaction time. The results indicated that metallic Au0 exhibits considerable catalytic activity and that Au nano-particle aggregation may be another reason for the AuCl3/AC catalytic activity in acetylene hydrochlorination. PMID:25994222

  5. Disappearance of back-to-back high p {sub T} hadron correlations in central Au+Au collisions at {radical}s{sub NN} = 200 GeV

    SciTech Connect

    Adler, C.; Ahammed, Z.; Allgower, C.; Amonett, J.; Anderson, B.D.; Anderson, M.; Averichev, G.S.; Balewski, J.; Barannikova, O.; Barnby, L.S.; Baudot, J.; Bekele, S.; Belaga, V.V.; Bellwied, R.; Berger, J.; Bichsel, H.; Billmeier, A.; Bland, L.C.; Blyth, C.O.; Bonner, B.E.; Boucham, A.; Brandin, A.; Bravar, A.; Cadman, R.V.; Caines, H.; Calderon de la Barca Sanchez, M.; Cardenas, A.; Carroll, J.; Castillo, J.; Castro, M.; Cebra, D.; Chaloupka, P.; Chattopadhyay, S.; Chen, Y.; Chernenko, S.P.; Cherney, M.; Chikanian, A.; Choi, B.; Christie, W.; Coffin, J.P.; Cormier, T.M.; Corral, M.M.; Cramer, J.G.; Crawford, H.J.; Derevschikov, A.A.; Didenko, L.; Dietel, T.; Draper, J.E.; Dunin, V.B.; Dunlop, J.C.; Eckardt, V.; Efimov, L.G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Fachini, P.; Faine, V.; Faivre, J.; Fatemi, R.; Filimonov, K.; Finch, E.; Fisyak, Y.; Flierl, D.; Foley, K.J.; Fu, J.; Gagliardi, C.A.; Gagunashvili, N.; Gans, J.; Gaudichet, L.; Germain, M.; Geurts, F.; Ghazikhanian, V.; Grachov, O.; Grigoriev, V.; Guedon, M.; Gushin, E.; Hallman, T.J.; Hardtke, D.; Harris, J.W.; Henry, T.W.; Heppelmann, S.; Herston, T.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G.W.; Horsley, M.; Huang, H.Z.; Humanic, T.J.; Igo, G.J.; Ishihara, A.; Ivanshin, Yu.I.; Jacobs, P.; Jacobs, W.W.; Janik, M.; Johnson, I.; Jones, P.G.; Judd, E.G.; Kaneta, M.; Kaplan, M.; Keane, D.; Kiryluk, J.; Kisiel, A.; Klay, J.; Klein, S.R.; Klyachko, A.; Kollegger, T.; Konstantinov, A.S.; Kopytine, M.; Kotchenda, L.; Kovalenko, A.D.; Kramer, M.; Kravtsov, P.; Krueger, K.; Kuhn, C.; Kulikov, A.I.; Kunde, G.J.; Kunz, C.L.; Kutuev, R.Kh.; Kuznetsov, A.A.; Lakehal-Ayat, L.; Lamont, M.A.C.; Landgraf, J.M.; Lange, S.; Lansdell, C.P.; Lasiuk, B.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Leontiev, V.M.; LeVine, M.J.; Li , Q.; Lindenbaum, S.J.; Lisa, M.A.; Liu, F.; Liu, L.; Liu, Z.; Liu, Q.J.; Ljubicic, T.; Llope, W.J.; LoCurto, G.; et al.

    2002-10-25

    Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudo-rapidity range and full azimuth in Au+Au and p+p collisions at = {radical}s{sub NN} = 200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes already observed in elementary collisions. A strong back-to-back correlation exists for p+p and peripheral Au + Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.

  6. Jet-hadron correlations in √[s(NN)]=200  GeV p+p and central Au+Au collisions.

    PubMed

    Adamczyk, L; Adkins, J K; Agakishiev, G; Aggarwal, M M; Ahammed, Z; Alekseev, I; Alford, J; Anson, C D; Aparin, A; Arkhipkin, D; Aschenauer, E C; Averichev, G S; Banerjee, A; Beavis, D R; Bellwied, R; Bhasin, A; Bhati, A K; Bhattarai, P; Bichsel, H; Bielcik, J; Bielcikova, J; Bland, L C; Bordyuzhin, I G; Borowski, W; Bouchet, J; Brandin, A V; Brovko, S G; Bültmann, S; Bunzarov, I; Burton, T P; Butterworth, J; Caines, H; Calderón de la Barca Sánchez, M; Cebra, D; Cendejas, R; Cervantes, M C; Chaloupka, P; Chang, Z; Chattopadhyay, S; Chen, H F; Chen, J H; Chen, L; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Chwastowski, J; Codrington, M J M; Contin, G; Cramer, J G; Crawford, H J; Cui, X; Das, S; Davila Leyva, A; De Silva, L C; Debbe, R R; Dedovich, T G; Deng, J; Derevschikov, A A; Derradi de Souza, R; Dhamija, S; di Ruzza, B; Didenko, L; Dilks, C; Ding, F; Djawotho, P; Dong, X; Drachenberg, J L; Draper, J E; Du, C M; Dunkelberger, L E; Dunlop, J C; Efimov, L G; Engelage, J; Engle, K S; Eppley, G; Eun, L; Evdokimov, O; Eyser, O; Fatemi, R; Fazio, S; Fedorisin, J; Filip, P; Finch, E; Fisyak, Y; Flores, C E; Gagliardi, C A; Gangadharan, D R; Garand, D; Geurts, F; Gibson, A; Girard, M; Gliske, S; Greiner, L; Grosnick, D; Gunarathne, D S; Guo, Y; Gupta, A; Gupta, S; Guryn, W; Haag, B; Hamed, A; Han, L-X; Haque, R; Harris, J W; Heppelmann, S; Hirsch, A; Hoffmann, G W; Hofman, D J; Horvat, S; Huang, B; Huang, H Z; Huang, X; Huck, P; Humanic, T J; Igo, G; Jacobs, W W; Jang, H; Judd, E G; Kabana, S; Kalinkin, D; Kang, K; Kauder, K; Ke, H W; Keane, D; Kechechyan, A; Kesich, A; Khan, Z H; Kikola, D P; Kisel, I; Kisiel, A; Koetke, D D; Kollegger, T; Konzer, J; Koralt, I; Kotchenda, L; Kraishan, A F; Kravtsov, P; Krueger, K; Kulakov, I; Kumar, L; Kycia, R A; Lamont, M A C; Landgraf, J M; Landry, K D; Lauret, J; Lebedev, A; Lednicky, R; Lee, J H; LeVine, M J; Li, C; Li, W; Li, X; Li, X; Li, Y; Li, Z M; Lisa, M A; Liu, F; Ljubicic, T; Llope, W J; Lomnitz, M; Longacre, R S; Luo, X; Ma, G L; Ma, Y G; Madagodagettige Don, D M M D; Mahapatra, D P; Majka, R; Margetis, S; Markert, C; Masui, H; Matis, H S; McDonald, D; McShane, T S; Minaev, N G; Mioduszewski, S; Mohanty, B; Mondal, M M; Morozov, D A; Mustafa, M K; Nandi, B K; Nasim, Md; Nayak, T K; Nelson, J M; Nigmatkulov, G; Nogach, L V; Noh, S Y; Novak, J; Nurushev, S B; Odyniec, G; Ogawa, A; Oh, K; Ohlson, A; Okorokov, V; Oldag, E W; Olvitt, D L; Pachr, M; Page, B S; Pal, S K; Pan, Y X; Pandit, Y; Panebratsev, Y; Pawlak, T; Pawlik, B; Pei, H; Perkins, C; Peryt, W; Pile, P; Planinic, M; Pluta, J; Poljak, N; Porter, J; Poskanzer, A M; Pruthi, N K; Przybycien, M; Pujahari, P R; Putschke, J; Qiu, H; Quintero, A; Ramachandran, S; Raniwala, R; Raniwala, S; Ray, R L; Riley, C K; Ritter, H G; Roberts, J B; Rogachevskiy, O V; Romero, J L; Ross, J F; Roy, A; Ruan, L; Rusnak, J; Rusnakova, O; Sahoo, N R; Sahu, P K; Sakrejda, I; Salur, S; Sandweiss, J; Sangaline, E; Sarkar, A; Schambach, J; Scharenberg, R P; Schmah, A M; Schmidke, W B; Schmitz, N; Seger, J; Seyboth, P; Shah, N; Shahaliev, E; Shanmuganathan, P V; Shao, M; Sharma, B; Shen, W Q; Shi, S S; Shou, Q Y; Sichtermann, E P; Singaraju, R N; Skoby, M J; Smirnov, D; Smirnov, N; Solanki, D; Sorensen, P; Spinka, H M; Srivastava, B; Stanislaus, T D S; Stevens, J R; Stock, R; Strikhanov, M; Stringfellow, B; Sumbera, M; Sun, X; Sun, X M; Sun, Y; Sun, Z; Surrow, B; Svirida, D N; Symons, T J M; Szelezniak, M A; Takahashi, J; Tang, A H; Tang, Z; Tarnowsky, T; Thomas, J H; Timmins, A R; Tlusty, D; Tokarev, M; Trentalange, S; Tribble, R E; Tribedy, P; Trzeciak, B A; Tsai, O D; Turnau, J; Ullrich, T; Underwood, D G; Van Buren, G; van Nieuwenhuizen, G; Vandenbroucke, M; Vanfossen, J A; Varma, R; Vasconcelos, G M S; Vasiliev, A N; Vertesi, R; Videbæk, F; Viyogi, Y P; Vokal, S; Vossen, A; Wada, M; Wang, F; Wang, G; Wang, H; Wang, J S; Wang, X L; Wang, Y; Wang, Y; Webb, G; Webb, J C; Westfall, G D; Wieman, H; Wissink, S W; Witt, R; Wu, Y F; Xiao, Z; Xie, W; Xin, K; Xu, H; Xu, J; Xu, N; Xu, Q H; Xu, Y; Xu, Z; Yan, W; Yang, C; Yang, Y; Yang, Y; Ye, Z; Yepes, P; Yi, L; Yip, K; Yoo, I-K; Yu, N; Zawisza, Y; Zbroszczyk, H; Zha, W; Zhang, J B; Zhang, J L; Zhang, S; Zhang, X P; Zhang, Y; Zhang, Z P; Zhao, F; Zhao, J; Zhong, C; Zhu, X; Zhu, Y H; Zoulkarneeva, Y; Zyzak, M

    2014-03-28

    Azimuthal angular correlations of charged hadrons with respect to the axis of a reconstructed (trigger) jet in Au+Au and p+p collisions at √[s(NN)]=200  GeV in STAR are presented. The trigger jet population in Au+Au collisions is biased toward jets that have not interacted with the medium, allowing easier matching of jet energies between Au+Au and p+p collisions while enhancing medium effects on the recoil jet. The associated hadron yield of the recoil jet is significantly suppressed at high transverse momentum (pTassoc) and enhanced at low pTassoc in 0%-20% central Au+Au collisions compared to p+p collisions, which is indicative of medium-induced parton energy loss in ultrarelativistic heavy-ion collisions. PMID:24724645

  7. Rationalization of Au concentration and distribution in AuNi@Pt core-shell nanoparticles for oxygen reduction reaction

    SciTech Connect

    An, Wei; Liu, Ping

    2015-09-18

    Improving the activity and stability of Pt-based core–shell nanocatalysts for proton exchange membrane fuel cells while lowering Pt loading has been one of the big challenges in electrocatalysis. Here, using density functional theory, we report the effect of adding Au as the third element to enhance the durability and activity of Ni@Pt core–shell nanoparticles (NPs) during the oxygen reduction reaction (ORR). Our results show that the durability and activity of a Ni@Pt NP can be finely tuned by controlling Au concentration and distribution. For a NiAu@Pt NP, the durability can be greatly promoted by thermodynamically favorable segregation of Au to replace the Pt atoms at vertex, edge, and (100) facets on the shell, while still keeping the ORR activity on the active Pt(111) shell as high as that of Ni@Pt nanoparticles. Such behavior strongly depends on a direct interaction with the Ni interlayer. The results not only highlight the importance of interplay between surface strain on the shell and the interlayer–shell interaction in determining the durability and activity but also provide guidance on how to maximize the usage of Au to optimize the performance of core–shell (Pt) nanoparticles. As a result, such understanding has allowed us to discover a novel NiAu@Pt nanocatalyst for the ORR.

  8. Rationalization of Au concentration and distribution in AuNi@Pt core-shell nanoparticles for oxygen reduction reaction

    DOE PAGESBeta

    An, Wei; Liu, Ping

    2015-09-18

    Improving the activity and stability of Pt-based core–shell nanocatalysts for proton exchange membrane fuel cells while lowering Pt loading has been one of the big challenges in electrocatalysis. Here, using density functional theory, we report the effect of adding Au as the third element to enhance the durability and activity of Ni@Pt core–shell nanoparticles (NPs) during the oxygen reduction reaction (ORR). Our results show that the durability and activity of a Ni@Pt NP can be finely tuned by controlling Au concentration and distribution. For a NiAu@Pt NP, the durability can be greatly promoted by thermodynamically favorable segregation of Au tomore » replace the Pt atoms at vertex, edge, and (100) facets on the shell, while still keeping the ORR activity on the active Pt(111) shell as high as that of Ni@Pt nanoparticles. Such behavior strongly depends on a direct interaction with the Ni interlayer. The results not only highlight the importance of interplay between surface strain on the shell and the interlayer–shell interaction in determining the durability and activity but also provide guidance on how to maximize the usage of Au to optimize the performance of core–shell (Pt) nanoparticles. As a result, such understanding has allowed us to discover a novel NiAu@Pt nanocatalyst for the ORR.« less

  9. Identified hadron transverse momentum spectra in Au+Au collisions at sNN=62.4 GeV

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J. Van; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wysłouch, B.

    2007-02-01

    Transverse momentum spectra of pions, kaons, protons, and antiprotons from Au+Au collisions at sNN = 62.4 GeV have been measured by the PHOBOS experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The identification of particles relies on three different methods: low momentum particles stopping in the first detector layers; the specific energy loss (dE/dx) in the silicon spectrometer, and time-of-flight measurement. These methods cover the transverse momentum ranges 0.03 0.2, 0.2 1.0, and 0.5 3.0 GeV/c, respectively. Baryons are found to have substantially harder transverse momentum spectra than mesons. The pT region in which the proton to pion ratio reaches unity in central Au+Au collisions at sNN = 62.4 GeV fits into a smooth trend as a function of collision energy. At low transverse mass, the spectra of various species exhibit a significant deviation from transverse mass scaling. The observed particle yields at very low pT are comparable to extrapolations from higher pT for kaons, protons and antiprotons. By comparing our results to Au+Au collisions at sNN = 200 GeV, we conclude that the net proton yield at midrapidity is proportional to the number of participant nucleons in the collision.

  10. Photoluminescence of Au - formed in 12CaO · 7Al 2O 3 single crystal by Au +-implantation

    NASA Astrophysics Data System (ADS)

    Miyakawa, M.; Kamioka, H.; Hirano, M.; Kamiya, T.; Hosono, H.

    2006-09-01

    Au + ion implantation with fluences from 1 × 10 14 to 3 × 10 16 cm -2 into 12CaO · 7Al 2O 3 (C12A7) single crystals was carried out at a sample temperature of 600 °C. The implanted sample with the fluence of 1 × 10 15 cm -2 exhibited photoluminescence (PL) bands peaking at ˜3.1 and ˜2.3 eV at ⩽150 K when excited by He-Cd laser (325 nm). This was the first observation of PL from C12A7. These two PL bands are possibly due to intra-ionic transitions of an Au - ion having the electronic configuration of 6 s2, judged from their similarities to those reported on Au - ions in alkali halides. However, when the concentration of the implanted Au ions exceeded the theoretical maximum value of anions encaged in C12A7 (˜2.3 × 10 21 cm -3), surface plasmon absorption appeared in the optical absorption spectrum, suggesting Au colloids were formed at such high fluences. These observations indicate that negative gold ions are formed in the cages of C12A7 by the Au + implantation if an appropriate fluence is chosen.

  11. Theoretical investigation of superconductivity in SrAuSi3 and SrAu2Si2

    NASA Astrophysics Data System (ADS)

    Arslan, Enes; Karaca, Ertuǧrul; Tütüncü, H. M.; Başoglu, A.; Srivastava, G. P.

    2016-08-01

    The structural and electronic properties of BaNiSn3-type SrAuSi3 and ThCr2Si2-type SrAu2Si2 have been investigated by using the planewave pseudopotential method and the density functional theory. The electronic structures and phonon dispersion relations of these two materials have been analyzed with and without the inclusion of spin-orbit interaction, and similarities and differences highlighted. By integrating the Eliashberg spectral function α2F(ω), the average electron-phonon coupling parameter is determined to be λ=0.47 for SrAuSi3 and 0.42 for SrAu2Si2. The largest contribution to the electron-phonon coupling for SrAuSi3 comes from the Si p electrons near the Fermi energy and Si-related vibrations. Using a reasonable value of μ* = 0.12 for the effective Coulomb repulsion parameter, the superconducting critical temperature Tc for SrAuSi3 is found to be 1.47 K which compares very well with its experimental value of 1.54 K.

  12. Versatile and efficient catalysts for energy and environmental processes: Mesoporous silica containing Au, Pd and Au-Pd

    NASA Astrophysics Data System (ADS)

    da Silva, Anderson G. M.; Fajardo, Humberto V.; Balzer, Rosana; Probst, Luiz F. D.; Lovón, Adriana S. P.; Lovón-Quintana, Juan J.; Valença, Gustavo P.; Schreine, Wido H.; Robles-Dutenhefner, Patrícia A.

    2015-07-01

    We described a versatile approach for the synthesis of Au/MCM-41, Pd/MCM-41 and Au-Pd/MCM-41 by the direct incorporation of the noble metals into the MCM-41 framework. The structural, textural and chemical properties were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), N2-adsorption (BET and BJH methods), H2-chemisorption, small angle X-ray scattering (SAXS), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). The nanomaterials, being comprised of Au, Pd and Au-Pd nanoparticles and possessing high surface areas were applied as versatile and efficient catalysts in benzene, toluene and o-xylene (BTX) oxidation and in the steam reforming of ethanol for hydrogen production. The results revealed that the catalytic behavior in both processes was influenced by the experimental conditions and the nature of the catalyst employed. The Au-Pd/MCM-41 catalyst was the most active in the BTX total oxidation. On the basis of characterization data, it was proposed that the close contact between Pd and Au and the higher dispersion of Pd may be responsible for the enhanced activity of the bimetallic catalyst. However, the strong interaction between the noble metals did not improve the performance of the bimetallic catalyst in ethanol steam reforming, the Pd/MCM-41 catalyst being the most active and selective for hydrogen production.

  13. Dynamical evolution of interplanetary magnetic fields and flows between 0.3 AU and 8.5 AU - Entrainment

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Schwenn, R.; Rosenbauer, H.

    1983-01-01

    An analysis is presented of the radial evolution of interplanetary flows and associated magnetic fields between 0.3 AU and 8.5 AU using data from Helios 1 and B Voyager 1, respectively. The results indicate that in moving to 8 AU the largest corotating streams swept up the slower flows and shocks into a relatively thin region in which they coalesced to form a single large-amplitude compression. As a result of this process, referred to as entrainment, memory of the sources and flow configurations near the sun is lost, while small-scale features are erased as the flows move outward and energy is transferred from small scales to large scales.It is concluded that in the outer solar system the structure of the solar wind may be dominated by large scale pressure waves separated by several AU, while beyond several AU most of the compression waves are no longer driven by streams, and the compression waves expand freely. At large distances (greater than 25 AU) these compression waves will have interacted extensively with one another producing another state of the solar wind, with fewer large-scale nonuniformities and more small-scale nonuniformities.

  14. Quantitative Interpretation of the Low-Bias Conductance of Au-Mesitylene-Au Molecular Junctions Formed from Mesitylene Monolayers.

    PubMed

    Wang, Hao; Jiang, Zhuoling; Wang, Yongfeng; Sanvito, Stefano; Hou, Shimin

    2016-07-18

    The atomic structure and electronic transport properties of Au-mesitylene-Au molecular junctions formed from a mesitylene monolayer without any anchoring groups are investigated by employing the non-equilibrium Green's function formalism combined with density functional theory. The intermolecular and adsorbate-substrate interactions are described by the non-local optB88 van der Waals functional. Two types of Au-mesitylene-Au molecular junctions are constructed, in which either an isolated mesitylene molecule or a mesitylene molecule embedded into a monolayer lying flat on one electrode surface is in contact with an atomic protrusion of the other electrode surface. The calculated low-bias conductance values of these two junctions are both in quantitative agreement with the reported experimental values [S. Afsari, Z. Li, and E. Borguet, Angew. Chem. Int. Ed. 2014, 53, 9771; Angew. Chem. 2014, 126, 9929]. This indicates that the measured conductance is intrinsic at the single-molecule Au-mesitylene-Au junction and that the intermolecular interactions in the mesitylene monolayer have little effect. PMID:27116017

  15. Effect of Au Content on Thermal Stability and Mechanical Properties of Au-Cu-Ag-Si Bulk Metallic Glasses

    NASA Astrophysics Data System (ADS)

    Guo, H.; Zhang, W.; Chen, M. W.; Saotome, Y.; Fukuhara, M.; Inoue, A.

    2011-06-01

    The thermal stability, glass-forming ability (GFA), and mechanical and electrical properties of Au-based Au x Si17Cu75.5- x Ag7.5 ( x = 40 to 75.5 at. pct) metallic glasses were investigated. The glass transition temperature ( T g ) and crystallization temperature ( T x ) decreased with increasing Au content. The ultralow T g values below 373 K (100 °C) were obtained for alloys with x = 55 to 75.5. The alloys with x = 45 to 70 exhibited a high stabilization of supercooled liquid and a high GFA, and the supercooled liquid region and critical sample diameter for glass formation were in the range of 31 K to 50 K and 2 to 5 mm, respectively. The compressive fracture strength ( σ c,f ), Young's modulus ( E), and Vicker's hardness ( H v ) of the bulk metallic glasses (BMGs) decreased with increasing Au content. A linear correlation between Au concentration and the characteristic temperature, i.e., T g and T x , and mechanical properties, i.e., σ c,f , E, and H v , as well as electrical resistivity can be found in the BMGs, which will be helpful for the composition design of the desirable Au-based BMGs with tunable physical properties.

  16. Amperometric immunosensor for carbofuran detection based on MWCNTs/GS-PEI-Au and AuNPs-antibody conjugate.

    PubMed

    Zhu, Ying; Cao, Yaoyao; Sun, Xia; Wang, Xiangyou

    2013-01-01

    In this paper, an amperometric immunosensor for the detection of carbofuran was developed. Firstly, multiwall carbon nanotubes (MWCNTs) and graphene sheets-ethyleneimine polymer-Au (GS-PEI-Au) nanocomposites were modified onto the surface of a glass carbon electrode (GCE) via self-assembly. The nanocomposites can increase the surface area of the GCE to capture a large amount of antibody, as well as produce a synergistic effect in the electrochemical performance. Then the modified electrode was coated with gold nanoparticles-antibody conjugate (AuNPs-Ab) and blocked with BSA. The monoclonal antibody against carbofuran was covalently immobilized on the AuNPs with glutathione as a spacer arm. The morphologies of the GS-PEI-Au nanocomposites and the fabrication process of the immunosensor were characterized by X-ray diffraction (XRD), ultraviolet and visible absorption spectroscopy (UV-vis) and scanning electron microscopy (SEM), respectively. Under optimal conditions, the immunosensor showed a wide linear range, from 0.5 to 500 ng/mL, with a detection limit of 0.03 ng/mL (S/N = 3). The as-constructed immunosensor exhibited notable performance features such as high specificity, good reproducibility, acceptable stability and regeneration performance. The results are mainly due to the excellent properties of MWCNTs, GS-PEI-Au nanocomposites and the covalent immobilization of Ab with free hapten binding sites for further immunoreaction. It provides a new avenue for amperometric immunosensor fabrication. PMID:23604029

  17. Heterojunction metal-oxide-metal Au-Fe{sub 3}O{sub 4}-Au single nanowire device for spintronics

    SciTech Connect

    Reddy, K. M. Punnoose, Alex; Hanna, Charles; Padture, Nitin P.

    2015-05-07

    In this report, we present the synthesis of heterojunction magnetite nanowires in alumina template and describe magnetic and electrical properties from a single nanowire device for spintronics applications. Heterojunction Au-Fe-Au nanowire arrays were electrodeposited in porous aluminum oxide templates, and an extensive and controlled heat treatment process converted Fe segment to nanocrystalline cubic magnetite phase with well-defined Au-Fe{sub 3}O{sub 4} interfaces as confirmed by the transmission electron microscopy. Magnetic measurements revealed Verwey transition shoulder around 120 K and a room temperature coercive field of 90 Oe. Current–voltage (I-V) characteristics of a single Au-Fe{sub 3}O{sub 4}-Au nanowire have exhibited Ohmic behavior. Anomalous positive magnetoresistance of about 0.5% is observed on a single nanowire, which is attributed to the high spin polarization in nanowire device with pure Fe{sub 3}O{sub 4} phase and nanocontact barrier. This work demonstrates the ability to preserve the pristine Fe{sub 3}O{sub 4} and well defined electrode contact metal (Au)–magnetite interface, which helps in attaining high spin polarized current.

  18. Les manifestations oculaires au cours de la pré-éclampsie sévère ou l’éclampsie au Centre Hospitalier Universitaire Sourô Sanou de Bobo Dioulasso

    PubMed Central

    Diallo, Jean Wenceslas; Méda, Nonfounikoun; Ahnoux-Zabsonré, Ahgbatouhabéba; Ouattara, Souleymane; Yanogo, Armande; Tougouma, Somnoma Jean Baptiste; Somé, Der; Sanou, Jérôme; Dolo, Mariam

    2015-01-01

    La pré-éclampsie sévère est un problème de santé publique. L'atteinte oculaire est une de ses nombreuses complications. Le but de notre travail était de décrire les atteintes oculaires chez les patientes présentant une pré-éclampsie et/ou éclampsie afin de contribuer à leur meilleure prise en charge. Il s'est agi d'une étude transversale descriptive à collecte prospective allant du 1er novembre 2013 au 31 juillet 2014, chez les patientes ayant souffert de pré-éclampsie sévère/éclampsie. Nous avons inclus 127 patientes dans notre étude. La moyenne d’âge des patientes de notre étude était de 26,37 ans (ET= 6,8 ans), avec des extrêmes de 15 et 40 ans. Les tranches d’âge les plus représentées étaient celles de 26 à 30 ans avec 29,1% des cas et celle des 15 à 20 ans avec 25,2%. Le diagnostic de pré-éclampsie sévère a été retenu dans 69,3% des cas. Les primigestes représentaient 40,9% de la population. Les troubles visuels à type de phosphènes ont été observés chez 33,1% des patientes. Nous avons noté un courant granulaire conjonctival dans 41,7%, des lésions du segment postérieur chez 32,3% des patientes. Ces résultats ont été discutés par rapport à la littérature, et nous notons plus de cas d'atteinte rétinienne. Nous n'avons pas trouvé de lien statistiquement significatif entre la tension artérielle à l'admission et le stade de la rétinopathie hypertensive. Les complications oculaires de la pré-éclampsie sévère sont très fréquentes et souvent ignorées. Les atteintes rétiniennes sont fréquentes mais de bon pronostic. PMID:26405485

  19. How Can We Understand Au8 Cores and Entangled Ligands of Selenolate- and Thiolate-Protected Gold Nanoclusters Au24(ER)20 and Au20(ER)16 (E = Se, S; R = Ph, Me)? A Theoretical Study.

    PubMed

    Takagi, Nozomi; Ishimura, Kazuya; Matsui, Masafuyu; Fukuda, Ryoichi; Matsui, Toru; Nakajima, Takahito; Ehara, Masahiro; Sakaki, Shigeyoshi

    2015-07-01

    The geometries and electronic structures of selenolate-protected Au nanoclusters, Au24(SeR)20 and Au20(SeR)16, and their thiolate analogues are theoretically investigated with DFT and SCS-MP2 methods, to elucidate the electronic structure of their unusual Au8 core and the reason why they have the unusual entangled "staple-like" chain ligands. The Au8 core is understood to be an [Au4](2+) dimer in which the [Au4](2+) species has a tetrahedral geometry with a closed-shell singlet ground state. The SCS-MP2 method successfully reproduced the distance between two [Au4](2+) moieties, but the DFT with various functionals failed it, suggesting that the dispersion interaction is crucial between these two [Au4](2+) moieties. The SCS-MP2-calculated formation energies of these nanocluster compounds indicate that the thiolate staple-like chain ligands are more stable than the selenolate ones, but the Au8 core more strongly coordinates with the selenolate staple-like chain ligands than with the thiolate ones. Though Au20(SeR)16 has not been reported yet, its formation energy is calculated to be large, suggesting that this compound can be synthesized as a stable species if the concentration of Au(SeR) is well adjusted. The aurophilic interactions between the staple-like chain ligands and between the Au8 core and the staple-like chain ligand play an important role for the stability of these compounds. Because of the presence of this autophilic interaction, Au24(SeR)20 is more stable than Au20(SeR)16 and the unusual entangled ligands are involved in these compounds. PMID:26076323

  20. Formation, Migration, and Reactivity of Au CO Complexes on Gold Surfaces

    DOE PAGESBeta

    Wang, Jun; McEntee, Monica; Tang, Wenjie; Neurock, Matthew; Baddorf, Arthur P.; Maksymovych, Petro; Yates, Jr, John T.

    2016-01-12

    Here, we report experimental as well as theoretical evidence that suggests Au CO complex formation upon the exposure of CO to active sites (step edges and threading dislocations) on a Au(111) surface. Room-temperature scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy, transmission infrared spectroscopy, and density functional theory calculations point to Au CO complex formation and migration. Room-temperature STM of the Au(111) surface at CO pressures in the range from 10^ 8 to 10^ 4 Torr (dosage up to 10^6 langmuir) indicates Au atom extraction from dislocation sites of the herringbone reconstruction, mobile Au CO complex formation and diffusion, and Aumore » adatom cluster formation on both elbows and step edges on the Au surface. The formation and mobility of the Au CO complex result from the reduced Au Au bonding at elbows and step edges leading to stronger Au CO bonding and to the formation of a more positively charged CO (CO +) on Au. These studies indicate that the mobile Au CO complex is involved in the Au nanoparticle formation and reactivity, and that the positive charge on CO increases due to the stronger adsorption of CO at Au sites with lower coordination numbers.« less

  1. First-principles study of the binary intermetallics in the Au-Rb system

    NASA Astrophysics Data System (ADS)

    Benmechri, Achraf; Djaballah, Yassine; Amer, Ahmed Said; Belgacem-Bouzida, Aissa; Bouderba, Hichem

    2014-06-01

    First-principles calculations within density functional theory (DFT) with the projector augmented wave (PAW) technique were used to investigate the stabilities of intermetallics in the Au-Rb system at 0 K. Four intermetallics: Au7Rb3, Au3Rb2, Au5Rb and AuRb were investigated in their observed experimental structures. The Au2Rb compound, reported in the Au-Rb phase diagrams without specifying explicitly its structure, was also investigated by inspecting several hypothetical structures. A suspect compound (AuRb2) was also investigated. Results show that: (i) The Au3Rb2 and Au7Rb3 compounds, which were never reported in any Au-Rb phase diagram, are stable at 0 K. (ii) The Au2Rb compound is not a ground state for all the tested structures. (iii) Stability of the Au5Rb and AuRb compounds was confirmed. (iv) The new compound AuRb2, not yet reported experimentally, is found mechanically stable at 0 K.

  2. Mechanical Properties and Fracture Behavior of Nanoporous Au

    SciTech Connect

    Biener, J; Hodge, A M; Wang, Y M; Hayes, J R; Hamza, A V

    2005-06-16

    Nanoporous metals have recently attracted considerable interest fueled by potential sensor and actuator applications. From a material science point of view, one of the key issues in this context is the synthesis of nanoporous metals with both high tensile and compressive strength. Nanoporous gold (np-Au) has been suggested as a candidate material for this application due to its monolithic character. The material can be synthesized by electrochemically-driven dealloying of Ag-Au alloys, and exhibits an open sponge-like structure of interconnecting ligaments with a typical pore size distribution on the nanometer length scale. However, besides the observation of a ductile-brittle transition very little is known about the mechanical behavior of this material. Here, we present our results regarding the mechanical properties and the fracture behavior of np-Au. Depth-sensing nanoindentation reveals that the yield strength of np-Au is almost one order of magnitude higher than the value predicted by scaling laws developed for macroscopic open-cell foams. The unexpectedly high value of the yield strength indicates the presence of a distinct size effect of the mechanical properties due to the sub-micron dimensions of the ligaments, thus potentially opening a door to a new class of high yield strength--low density materials. The failure mechanism of np-Au under tensile stress was evaluated by microscopic examination of fracture surfaces using scanning electron microscopy. On a macroscopic level, np-Au is a very brittle material. However, microscopically np-Au is very ductile as ligaments strained by as much as 200% can be observed in the vicinity of crack tips. Cell-size effects on the microscopic failure mechanism were studied by annealing experiments whereby increasing the typical pore size/ligament diameter from {approx}100 nm to {approx}1{micro}m.

  3. Enantiospecific adsorption of cysteine on a chiral Au34 cluster

    NASA Astrophysics Data System (ADS)

    de Jesús Pelayo, José; Valencia, Israel; Díaz, Gabriela; López-Lozano, Xóchitl; Garzón, Ignacio L.

    2015-12-01

    The interaction of biological molecules like chiral amino acids with chiral metal clusters is becoming an interesting and active field of research because of its potential impact in, for example, chiral molecular recognition phenomena. In particular, the enantiospecific adsorption (EA) of cysteine (Cys) on a chiral Au55 cluster was theoretically predicted a few years ago. In this work, we present theoretical results, based on density functional theory, of the EA of non-zwitterionic cysteine interacting with the C3-Au34 chiral cluster, which has been experimentally detected in gas phase, using trapped ion electron diffraction. Our results show that, indeed, the adsorption energy of the amino acid depends on which enantiomers participate in the formation Cys-Au34 chiral complex. EA was obtained in the adsorption modes where both the thiol, and the thiol-amino functional groups of Cys are adsorbed on low-coordinated sites of the metal cluster surface. Similarly to what was obtained for the Cys-Au55 chiral complex, in the present work, it is found that the EA is originated from the different strength and location of the bond between the COOH functional group and surface Au atoms of the Au34 chiral cluster. Calculations of the vibrational spectrum for the different Cys-Au34 diastereomeric complexes predict the existence of a vibro-enantiospecific effect, indicating that the vibrational frequencies of the adsorbed amino acid depend on its handedness. Contribution to the Topical Issue "Atomic Cluster Collisions (7th International Symposium)", edited by G. Delgado Barrio, A. Solov'Yov, P. Villarreal, R. Prosmiti.

  4. Observations of interstellar Ne at 1 AU

    NASA Astrophysics Data System (ADS)

    Drews, Christian; Berger, Lars; Wimmer-Schweingruber, Robert F.; Galvin, Antoinette B.; Klecker, Berndt; Möbius, Eberhard

    2010-05-01

    as interstellar helium and neon using STEREO PLASTIC's Pulse Height Analysis data. We have investigated long time series of pickup count rates between 2007 and 2009 of He+, C+, and O+ which show a significant formation of the focusing cone for the interstellar component of pickup ions. In agreement with theoretical expectations focusing of inner-source PUIs, i.e. C+ and O+, is not observed. By comparing mass-per-charge spectra inside and outside the cone, we have succeeded in distinguishing interstellar from inner-source Ne+ pickup ions. This constitutes the first discovery of interstellar Ne at 1 AU.

  5. Structure and Properties of Sr 2Au 3In 4 and Eu 2Au 3In 4

    NASA Astrophysics Data System (ADS)

    Hoffmann, Rolf-Dieter; Pöttgen, Rainer; Rosenhahn, Carsten; Mosel, Bernd D.; Künnen, Bernd; Kotzyba, Gunter

    1999-06-01

    Sr2Au3In4 was synthesized by reacting the elements in glassy carbon crucibles under an argon atmosphere in a high-frequency furnace. Eu2Au3In4 was obtained in the same way but starting with EuAuIn as a precursor and admixing indium and gold. Both compounds were investigated by X-ray diffraction on powders and single crystals: anti-Hf2Co4P3 type, Poverline62m, a=1501.6(9) pm, c=457.9(2) pm, wR2=0.0734, 1030 F2 values, 45 variables for Sr2Au2.85In4.15 and a=1489.7(3) pm, c= 454.90(7) pm, wR2=0.1222, 1051 F2 values, 45 variables for Eu2Au3In4. One gold site in the strontium compound shows a mixed occupancy with indium atoms indicating a small homogeneity range according to Sr2Au3-xIn4+x. Striking structural motifs of Sr2Au3In4 and Eu2Au3In4 are gold-centered trigonal prisms formed by the strontium (europium) and indium atoms. All gold atoms have coordination number 9 in the form of tricapped trigonal prisms. The indium atoms in Sr2Au3In4 and Eu2Au3In4 occupy the cobalt positions of the Hf2Co4P3 type and the more electronegative gold atoms take the phosphorus positions, indicating that Sr2Au3In4 and Eu2Au3In4 may be considered as ternary aurides. The gold and indium atoms form three-dimensional [Au3In4]4- polyanions in which the divalent strontium and europium atoms occupy distorted hexagonal tubes. Magnetic susceptibility measurements of Eu2Au3In4 show paramagnetic behavior above 50 K with an experimental magnetic moment of 7.88(5) μB/Eu indicating Eu2+. Antiferromagnetic ordering is detected at 9.5(5) K at low external fields. A metamagnetic transition is observed at 2 K at a critical field of 0.5(2) T. The experimental saturation moment at 2 K and 5.5 T is 5.95(5) μB/Eu. Electrical conductivity investigations exhibit metallic behavior with a room temperature value of 75±10 μΩcm for the specific resistivity. 151Eu Mössbauer spectroscopic measurements show a broadened line with an isomer shift of -10.5(5) mm/s at 78 K in accordance with several sites of divalent

  6. Effects of stretching and compression on conducting properties of an Au-alkanedithiol-Au molecular junction

    NASA Astrophysics Data System (ADS)

    Xie, Fang; Zhang, Xiao-Jiao; Yu, Ji-Hai; Xu, Hua; Chu, Yu-Fang; Fan, Zhi-Qiang

    2016-03-01

    We have studied the effects of stretching and compression on the electronic properties of 7-alkanedithiol covalently linked to two Au electrodes. Results show a progressive increase in conductivity upon molecule compression and decrease with molecule stretching. The notable conductance increase at high compression is attributed to a significant modification of HOMO and LUMO orbitals of the junction, which enhances electron delocalization and promotes tunneling across the junction. More important, the current switching ratios between the various stages of compressed/extended geometries almost maintain the constant values on the bias region from 0 V to 2 V. In other word, the mechanically-induced conductance enhancement and weakening are stable within a large bias voltage range.

  7. Adsorption of oxygen on Au(111) by exposure to ozone

    NASA Astrophysics Data System (ADS)

    Saliba, N.; Parker, D. H.; Koel, B. E.

    1998-08-01

    Atomic oxygen coverages of up to 1.2 ML may be cleanly adsorbed on the Au(111) surface by exposure to O 3 at 300 K. We have studied the adsorbed oxygen layer by AES, XPS, HREELS, LEED, work function measurements and TPD. A plot of the O(519 eV)/Au(239 eV) AES ratio versus coverage is nearly linear, but a small change in slope occurs at ΘO=0.9 ML. LEED observations show no ordered superlattice for the oxygen overlayer for any coverage studied. One-dimensional ordering of the adlayer occurs at low coverages, and disordering of the substrate occurs at higher coverages. Adsorption of 1.0 ML of oxygen on Au(111) increases the work function by +0.80 eV, indicating electron transfer from the Au substrate into an oxygen adlayer. The O(1s) peak in XPS has a binding energy of 530.1 eV, showing only a small (0.3 eV) shift to a higher binding energy with increasing oxygen coverage. No shift was detected for the Au 4f 7/2 peak due to adsorption. All oxygen is removed by thermal desorption of O 2 to leave a clean Au(111) surface after heating to 600 K. TPD spectra initially show an O 2 desorption peak at 520 K at low ΘO, and the peak shifts to higher temperatures for increasing oxygen coverages up to ΘO=0.22 ML. Above this coverage, the peak shifts very slightly to higher temperatures, resulting in a peak at 550 K at ΘO=1.2 ML. Analysis of the TPD data indicates that the desorption of O 2 from Au(111) can be described by first-order kinetics with an activation energy for O 2 desorption of 30 kcal mol -1 near saturation coverage. We estimate a value for the Au-O bond dissociation energy D(Au-O) to be ˜56 kcal mol -1.

  8. Systematics of Fragment Spectra and Collective Motion in Au + Au Collisions

    NASA Astrophysics Data System (ADS)

    Keane, Declan

    1998-04-01

    The importance of comprehensive data on single-particle spectra and collective motion has been recognized for many years. The literature contains many references to the need for full ``triple-differential cross section" measurements (d^3σ/dp_⊥ dy dφr , or their equivalent, where φr signifies azimuth relative to the event reaction plane). There are grounds for arguing that talk about triple-differential cross sections is misleading in this context, because the ideal measurements for constraining models in fact resemble eighth-order differentials d^8 σ / dp_⊥ dy dφr dM dm_frag dAt dAp dE_p, where M is a measure of event centrality (e.g., multiplicity), m_frag steps through the possible fragment species, and the subscripts t and p refer to target and projectile, respectively. The ideal goal of a meaningful measurement of the full parameter space in principle requires prohibitively large statistics, and even if those statistics were available, many millions of spectra would be needed to present the eighth-order differential cross sections. In practice, the problem is manageable because the structure of the events in the eight-dimensional parameter space is not nearly as complex as it could be in principle, and a relatively simple phenomenological framework can describe all the known relevant features of the events. The above points will be discussed mostly in the context of measurements of Au + Au data from the EOS Time Projection Chamber at beam energies of 0.25A GeV and above.

  9. Dielectron production in Au + Au collisions at √{sN N}=200 GeV

    NASA Astrophysics Data System (ADS)

    Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Al-Ta'Ani, H.; Angerami, A.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Aschenauer, E. C.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bassalleck, B.; Bathe, S.; Baublis, V.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Castera, P.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Connors, M.; Csanád, M.; Csörgő, T.; Dairaku, S.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Dharmawardane, K. V.; Dietzsch, O.; Ding, L.; Dion, A.; Diss, P. B.; Do, J. H.; Donadelli, M.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; Edwards, S.; Efremenko, Y. V.; Engelmore, T.; Enokizono, A.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fusayasu, T.; Gainey, K.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, A.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, X.; Gonin, M.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grosse Perdekamp, M.; Gunji, T.; Guo, L.; Gustafsson, H.-Å.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamilton, H. F.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Haseler, T. O. S.; Hashimoto, K.; Haslum, E.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Horaguchi, T.; Hori, Y.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Issah, M.; Ivanishchev, D.; Jacak, B. V.; Javani, M.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kaneti, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Kawall, D.; Kazantsev, A. V.; Kempel, T.; Key, J. A.; Khachatryan, V.; Khanzadeev, A.; Kijima, K. M.; Kim, B. I.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; Kim, H. J.; Kim, K.-B.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kimelman, B.; Kinney, E.; Kiss, Á.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Komatsu, Y.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Král, A.; Krizek, F.; Kunde, G. J.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, B.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Lee, S. R.; Leitch, M. J.; Leite, M. A. L.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Linden Levy, L. A.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Masumoto, S.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyachi, Y.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, H. J.; Moon, T.; Morrison, D. P.; Motschwiller, S.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagashima, K.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Nederlof, A.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ouchida, M.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, B. H.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Pei, H.; Peng, J.-C.; Pereira, H.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Qu, H.; Rak, J.; Ramson, B. J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Rinn, T.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sano, M.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seidl, R.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Slunečka, M.; Snowball, M.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takagui, E. M.; Takahara, A.; Taketani, A.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Themann, H.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, L.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, R.; Towell, R. S.; Tserruya, I.; Tsuchimoto, Y.; Tsuji, T.; Vale, C.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vossen, A.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Wei, R.; White, A. S.; White, S. N.; Winter, D.; Wolin, S.; Woody, C. L.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yang, R.; Yanovich, A.; Ying, J.; Yokkaichi, S.; Yoo, J. H.; Yoon, I.; You, Z.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.; Zou, L.; Phenix Collaboration

    2016-01-01

    We present measurements of e+e- production at midrapidity in Au +Au collisions at √{sNN}=200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (me e<5 GeV /c2) and pair transverse momentum (pT<5 GeV /c ) for minimum bias and for five centrality classes. The e+e- yield is compared to the expectations from known sources. In the low-mass region (me e=0.30 - 0.76 GeV /c2 ) there is an enhancement that increases with centrality and is distributed over the entire pair pT range measured. It is significantly smaller than previously reported by the PHENIX experiment and amounts to 2.3 ±0.4 (stat )±0.4 (syst )±0.2 (model ) or to 1.7 ±0.3 (stat )±0.3 (syst )±0.2 (model ) for minimum bias collisions when the open heavy-flavor contribution is calculated with pythia or mc@nlo, respectively. The inclusive mass and pT distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the ρ meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (me e=1.2 - 2.8 GeV /c2 ), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.

  10. Intriguing centrality dependence of the Au-Au source size at the AGS

    SciTech Connect

    Baker, M.D.; The E802 Collaboration

    1996-06-01

    One of the main goals of high energy heavy ion physics is to establish the existence of a deconfined phase of nuclear matter--the quark-gluon plasma--at high temperatures or densities. One possible signature of such a phase transition, especially if it were first order, would be a larger source size or lifetime than a similar hadronic system. At current AGS energies, we attempt to form a quark- gluon plasma by achieving a high baryon density for a period of time in the center of the collision region. For a given density threshold, the size of this high density region should be a strong function of the impact parameter: the more central the event, the larger the high density region. Therefore, one possible signature of a quark-gluon plasma would be a sudden change in system lifetime or size as a function of the centrality of the collision. In this talk we present an intriguing effect which was not predicted for simple hadronic systems: a rapid increase of the HBT-measured source radius parameter for pion pairs with increasing centrality for Au-Au collisions at a beam momentum of 11.45 A GeV/c on a fixed target. Experience has shown, however, that we must be cautious in our interpretation. A complete understanding of the collision dynamics at a given energy must be built up from several measurements and new, but conventional, hadronic explanations must be considered for such unexpected effects. More study is needed, therefore, before any strong conclusions can be reached.

  11. Drowned reefs and antecedent karst topography, Au'au channel, S.E. Hawaiian Islands

    USGS Publications Warehouse

    Grigg, R.W.; Grossman, E.E.; Earle, S.A.; Gittings, S.R.; Lott, D.; McDonough, J.

    2002-01-01

    During the last glacial maximum (LGM), about 21,000 years ago, the Hawaiian Islands of Maui, Lanai, and Molokai were interconnected by limestone bridges, creating a super-island known as Maui-Nui. Approximately 120 m of sea-level rise during the Holocene Transgression flooded, and then drowned, these bridges separating the islands by inter-island channels. A new multibeam high-resolution bathymetric survey of the channels between the islands, coupled with observations and video-transects utilizing DeepWorker-2000 submersibles, has revealed the existence of numerous drowned reef features including concentric solution basins, solution ridges (rims), sand and sediment plains, and conical-shaped reef pinnacles. The concentric basins contain flat lagoon-like bottoms that are rimmed by steep-sided limestone walls. Undercut notches rim the basins at several depths, marking either sea-level still stands or paleo-lake levels. All of the solution basins shallower than 120 m were subaerial at the LGM, and at one stage or another may have been shallow shoreline lakes. Today, about 70 drowned reef pinnacles are scattered across the Maui-Lanai underwater bridge and all are situated in wave-sheltered positions. Most drowned during the interval between 14,000 and 10,000 years ago when sea-level rise averaged 15 mm/year. Virtually all of the surficial topography in the Au'au Channel today is a product of karst processes accentuated by marginal reef growth during the Holocene. Both the submerged basins and the drowned reefs represent an archive of sea-level and climate history in Hawaii during the late Quaternary.

  12. Phenomenological magnetic modeling of Au:Fe:Au nano-onions

    NASA Astrophysics Data System (ADS)

    Wiggins, J.; Carpenter, Everett E.; O'Connor, Charles J.

    2000-05-01

    A new type of materials, the nano-onions, has been shown to exhibit GMR. These nanostructured composites consist of a nonmagnetic core coated with a thin layer of a bulk ferromagnet with a passivating nonmagnetic surface layer. The nano-onion investigated had a 3 nm Au core, a 1 nm Fe layer, and a 2 nm Au coating; all values correspond to the radius. The materials were manufactured using a sequential reverse micelle technique, detailed elsewhere. The sample preparation method produces a powder sample was cold pressed into a pellet. Magnetic investigation of the sample indicated that the material was superparamagnetic with a blocking temperature of 52 K for particles approximately 8 nm in diameter. At 10 K, the coercivity was 420 Oe, indicating a large degree of order. The GMR was measured over the entire temperature range available. At 10 K, in 5 T, a 1% MR was observed. The GMR was modeled using a simple phenomenological magnetic model initially used to study GMR granular thin films. To more accurately match the physical parameters of reverse micelles, the conventional log-normal particle size distribution was replaced with a normal distribution. The model suggested that the system consisted of an ensemble of 1.3 nm particles with a standard deviation of 0.07. The model does not detect the entire 8 nm diam, rather it detects the individual walls of the shell. In this context, it has shown that a simple phenomenological model can accurately predict the magnetic and electronic behavior of nano-onions.

  13. Dielectron production in Au plus Au collisions at root s(NN)=200 GeV

    SciTech Connect

    Adare, A.; Awes, Terry C; Cianciolo, Vince; Efremenko, Yuri V; Enokizono, A.; Silvermyr, D.; Sorensen, Soren P; Stankus, Paul W; Young, Glenn R; PHENIX, Collaboration [

    2016-01-01

    We present measurements of e(+)e-production at midrapidity in Au + Au collisions at root s(NN) = 200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (m(ee) < 5 GeV/c(2)) and pair transverse momentum (p(T) < 5 GeV/c) for minimum bias and for five centrality classes. The e(+)e(-) yield is compared to the expectations from known sources. In the low-mass region (m(ee) = 0.30-0.76 GeV/c(2)) there is an enhancement that increases with centrality and is distributed over the entire pair p(T) range measured. It is significantly smaller than previously reported by the PHENIX experiment and amounts to 2.3 +/- 0.4(stat) +/- 0.4(syst) +/- 0.2(model) or to 1.7 +/- 0.3(stat) +/- 0.3(syst) +/- 0.2(model) for minimum bias collisions when the open heavy-flavor contribution is calculated with PYTHIA or MC@NLO, respectively. The inclusive mass and p(T) distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the rho meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (m(ee) = 1.2-2.8 GeV/c(2)), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.

  14. Dielectron production in Au plus Au collisions at root s(NN)=200 GeV

    DOE PAGESBeta

    Adare, A.; Awes, Terry C; Cianciolo, Vince; Efremenko, Yuri V; Enokizono, A.; Read, K. F.; Silvermyr, D.; Sorensen, Soren P; Stankus, Paul W; Young, Glenn R; et al

    2016-01-01

    We present measurements of e(+)e-production at midrapidity in Au + Au collisions at root s(NN) = 200 GeV. The invariant yield is studied within the PHENIX detector acceptance over a wide range of mass (m(ee) < 5 GeV/c(2)) and pair transverse momentum (p(T) < 5 GeV/c) for minimum bias and for five centrality classes. The e(+)e(-) yield is compared to the expectations from known sources. In the low-mass region (m(ee) = 0.30-0.76 GeV/c(2)) there is an enhancement that increases with centrality and is distributed over the entire pair p(T) range measured. It is significantly smaller than previously reported by themore » PHENIX experiment and amounts to 2.3 +/- 0.4(stat) +/- 0.4(syst) +/- 0.2(model) or to 1.7 +/- 0.3(stat) +/- 0.3(syst) +/- 0.2(model) for minimum bias collisions when the open heavy-flavor contribution is calculated with PYTHIA or MC@NLO, respectively. The inclusive mass and p(T) distributions, as well as the centrality dependence, are well reproduced by model calculations where the enhancement mainly originates from the melting of the rho meson resonance as the system approaches chiral symmetry restoration. In the intermediate-mass region (m(ee) = 1.2-2.8 GeV/c(2)), the data hint at a significant contribution in addition to the yield from the semileptonic decays of heavy-flavor mesons.« less

  15. Herringbone and triangular patterns of dislocations in Ag, Au, and AgAu alloy films on Ru(0001).

    SciTech Connect

    Thayer, Gayle Echo; de la Figuera, Juan; Bartelt, Norman Charles; Carter, C. Barrington; Hwang, R. Q.; Thurmer, Konrad; Ling, W. L.; Hamilton, John C.; McCarty, Kevin F.

    2008-10-01

    We have studied the dislocation structures that occur in films of Ag, Au, and Ag{sub 0.5}Au{sub 0.5} alloy on a Ru(0001) substrate. Monolayer (ML) films form herringbone phases while films two or more layers thick contain triangular patterns of dislocations. We use scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) to determine how the film composition affects the structure and periodicity of these ordered structures. One layer of Ag forms two different herringbone phases depending on the exact Ag coverage and temperature. Low-energy electron microscopy (LEEM) establishes that a reversible, first-order phase transition occurs between these two phases at a certain temperature. We critically compare our 1 ML Ag structures to conflicting results from an X-ray scattering study [H. Zajonz et al., Phys. Rev. B 67 (2003) 155417]. Unlike Ag, the herringbone phases of Au and AgAu alloy are independent of the exact film coverage. For two layer films in all three systems, none of the dislocations in the triangular networks thread into the second film layer. In all three systems, the in-plane atomic spacing of the second film layer is nearly the same as in the bulk. Film composition does, however, affect the details of the two layer structures. Ag and Au films form interconnected networks of dislocations, which we refer to as 'trigons.' In 2 ML AgAu alloy, the dislocations form a different triangular network that shares features of both trigon and moire structures. Yet another well-ordered structure, with square symmetry, forms at the boundaries of translational trigon domains in 2 ML Ag films but not in Au films.

  16. Observations of high spin states in {sup 179}Au

    SciTech Connect

    Carpenter, M.P.; Ahmad, I.; Blumenthal, D.J.

    1995-08-01

    As part of a current study on the properties of the {pi} i{sub 13/2} intruder state in the A = 175-190 region, we conducted an experiment at ATLAS to observe high spin states in {sup 179}Au utilizing the reaction {sup 144}Sm({sup 40}Ar,p4n) at beam energies of 207 MeV and 215 MeV. To aid in the identification of {sup 179}Au, and to filter out the large amount of events from fission by-products, the Fragment Mass Analyzer was utilized in conjunction with ten Compton-suppression germanium detectors. In total, 11 x 10{sup 6} {gamma}-{gamma} and 4 x 10{sup 5} {gamma}-recoil events were collected. By comparing {gamma}-rays in coincidence with an A = 179 recoil mass gate and {gamma}-rays in coincidence with Au K{alpha} and K{beta} X-rays, ten {gamma}-rays were identified as belonging to {sup 179}Au. Based on {gamma}-ray coincidence relationships and on comparisons with neighboring odd-A Au nuclei, we constructed a tentative level scheme and assigned a rotational-like sequence to the {pi} i{sub 13/2} proton configuration.

  17. AU-rich RNA binding proteins in hematopoiesis and leukemogenesis.

    PubMed

    Baou, Maria; Norton, John D; Murphy, John J

    2011-11-24

    Posttranscriptional mechanisms are now widely acknowledged to play a central role in orchestrating gene-regulatory networks in hematopoietic cell growth, differentiation, and tumorigenesis. Although much attention has focused on microRNAs as regulators of mRNA stability/translation, recent data have highlighted the role of several diverse classes of AU-rich RNA-binding protein in the regulation of mRNA decay/stabilization. AU-rich elements are found in the 3'-untranslated region of many mRNAs that encode regulators of cell growth and survival, such as cytokines and onco/tumor-suppressor proteins. These are targeted by a burgeoning number of different RNA-binding proteins. Three distinct types of AU-rich RNA binding protein (ARE poly-U-binding degradation factor-1/AUF1, Hu antigen/HuR/HuA/ELAVL1, and the tristetraprolin/ZFP36 family of proteins) are essential for normal hematopoiesis. Together with 2 further AU-rich RNA-binding proteins, nucleolin and KHSRP/KSRP, the functions of these proteins are intimately associated with pathways that are dysregulated in various hematopoietic malignancies. Significantly, all of these AU-rich RNA-binding proteins function via an interconnected network that is integrated with microRNA functions. Studies of these diverse types of RNA binding protein are providing novel insight into gene-regulatory mechanisms in hematopoiesis in addition to offering new opportunities for developing mechanism-based targeted therapeutics in leukemia and lymphoma. PMID:21917750

  18. HELIUM ION ANISOTROPIES IN COROTATING INTERACTION REGIONS AT 1 AU

    SciTech Connect

    Ebert, R. W.; Desai, M. I.; Dayeh, M. A.; Mason, G. M.

    2012-08-01

    We investigated the first-order flow anisotropies in the solar wind frame of {approx}0.06-0.95 MeV nucleon{sup -1} He ions during three corotating interaction region (CIR)-associated particle intensity enhancements observed at 1 AU by Wind, examining CIRs with (1) a reverse shock, (2) a well-formed compression region, and (3) a weak compression region. We identified anti-sunward flows in the compression region downstream of the CIR trailing edge in the events with a reverse shock and well-formed compression that transitioned to sunward flows across and upstream of this boundary. These observations suggest that the trailing edge is organizing the He ion flows and is a local source for the particles in these events, this source being inside 1 AU prior to the trailing edge arrival and beyond 1 AU after its passage. The event with the weak compression region had predominantly sunward flows throughout, indicating that the source of the He ions was beyond 1 AU. These observations provide compelling evidence that He ions at 1 AU can be accelerated to suprathermal energies at the CIR trailing edge in events where the compression region is well formed.

  19. U+U and Cu+Au results from PHENIX

    NASA Astrophysics Data System (ADS)

    Iordanova, Aneta; PHENIX Collaboration

    2013-08-01

    The flexibility of RHIC to collide different nuclei provides experiments with a rich set of data to systematically test models and scaling behaviors in various collision systems. The latest RHIC run collided U+U and Cu+Au nuclei. These collisions promise an array of unique initial geometrical configurations. For example, in U+U collisions the slightly elongated nuclei overlap in a variety of different ways such that, even at zero impact parameter, distinct configurations exist. In central Cu+Au collisions the Cu nucleus is completely embedded within the Au. Such geometries present an opportunity to measure the wide range of initial energy densities of these systems. They also allow the study of some unique features arising from these configurations. In particular, the odd harmonics from the Cu+Au system offer sensitivity to v3 generated from the collision geometry as opposed to fluctuations in a symmetric system. In these proceedings the analysis status of the recently taken U+U and Cu+Au data in PHENIX is presented. The results from the global particle production and the challenges in analyzing these asymmetric systems is discussed.

  20. Au/metal oxides for low temperature CO oxidation

    SciTech Connect

    Srinivas, G.; Wright, J.; Bai, C.S.; Cook, R.

    1996-12-31

    Oxidation of carbon monoxide is important for several operations including fuel cells and carbon dioxide lasers. Room temperature CO oxidation has been investigated on a series of Au/metal oxide catalysts at conditions typical of spacecraft atmospheres; CO = 50 ppm, CO{sub 2} = 7,000 ppm, H{sub 2}O = 40% (RH) at 25{degrees}C, balance = air, and gas hourly space velocities of 7,000-60,000 hr{sup -1}. The addition of Au increases the room temperature CO oxidation activity of the metal oxides dramatically. All the Au/metal oxides deactivate during the CO oxidation reaction, especially in the presence of CO{sub 2} in the feed. The stability of the Au/metal oxide catalysts decreases in the following order: TiO{sub 2} > Fe{sub 2}O{sub 3} > NiO > Co{sub 3}O{sub 4}. The stability appears to decrease with an increase in the basicity of the metal oxides. In situ FTIR of CO adsorption on Au/TiO{sub 2} at 25{degrees}C indicates the formation of adsorbed CO, carboxylate, and carbonate species on the catalyst surface.

  1. Structure of SiAu16: can a silicon atom be stabilized in a gold cage?

    PubMed

    Sun, Qiang; Wang, Qian; Chen, Gang; Jena, Puru

    2007-12-01

    Nanostructures of Au and Si as well as Au-Si hybrid structures are topics of great current interest from both scientific and technological points of view. Recent discovery of Au clusters having fullerene-like geometries and the possibility of endohedral complexes with Si atoms inside the Au cage opens new possibilities for designing Au-Si nanostructures. Using ab initio simulated annealing method we have examined the stability of Si-Au16 endohedral complex. Contrary to what we believed, we find that the endohedral configuration is metastable and the structure where Si atom binds to the exterior surface of the Au16 cage is the lowest energy structure. The bonding of Si to Au cluster mimics its behavior of that in bulk and liquid phase of Au. In addition, doping of Si in high concentration would cause fracture and embrittlement in gold nanostructures just as it does in the bulk phase. Covalent bonding between Au-Au and Au-Si is found to be a dominant feature in the stability of the Au-Si nanostructures. Our study provides insight that may be useful in fabricating hybrid Au-Si nanostructures for applications microelectronics, catalysis, biomedicine, and jewelry industry. PMID:18067374

  2. Study on antibacterial activity of chemically synthesized PANI-Ag-Au nanocomposite

    NASA Astrophysics Data System (ADS)

    Boomi, Pandi; Prabu, Halliah Gurumallesh; Manisankar, Paramasivam; Ravikumar, Sundaram

    2014-05-01

    Pristine polyaniline (PANI), PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites have been successfully synthesized by chemical oxidative polymerization method using aniline as monomer, ammonium persulphate as oxidant and metal (Ag, Au and Ag-Au) colloids. UV-Vis analysis exhibited surface Plasmon resonances of Ag, Au, Ag-Au nanoparticles. FT-IR spectra revealed the shift in peak position of N-H stretching. X-ray diffraction (XRD) results confirm the presence of Ag, Au and Au-Ag nanoparticles. HR-TEM images show nanosizes of Ag, Au, Ag-Au and the incorporation of such nanoparticles into the PANI matrix. Pristine PANI, PANI-Ag, PANI-Au and PANI-Ag-Au nanocomposites were tested for antibacterial activity by agar well diffusion method. PANI-Ag-Au nanocomposite exhibited higher antibacterial activity against both gram-positive [Streptococcus sp. (MTCC 890), Staphylococcus sp. (MTCC 96)] and gram-negative bacteria [Escherichia coli (MTCC 1671) and Klebsiella sp. (MTCC 7407)] when compared with PANI-Ag nanocomposite, PANI-Au nanocomposite and pristine PANI. The novelty of this study is the polymer-bimetal synthesis and its antibacterial potential.

  3. Atomic and electronic structures of Si(1 1 1)-(√3 x √3)R30°-Au and (6 × 6)-Au surfaces.

    PubMed

    Patterson, C H

    2015-12-01

    Si(1 1 1)-Au surfaces with around one monolayer of Au exhibit many ordered structures and structures containing disordered domain walls. Hybrid density functional theory (DFT) calculations presented here reveal the origin of these complex structures and tendency to form domain walls. The conjugate honeycomb chain trimer (CHCT) structure of the [Formula: see text]-Au phase contains Si atoms with non-bonding surface states which can bind Au atoms in pairs in interstices of the CHCT structure and make this surface metallic. Si adatoms adsorbed on the [Formula: see text]-Au surface induce a gapped surface through interaction with the non-bonding states. Adsorption of extra Au atoms in interstitial sites of the [Formula: see text]-Au surface is stabilized by interaction with the non-bonding orbitals and leads to higher coverage ordered structures including the [Formula: see text]-Au phase. Extra Au atoms bound in interstitial sites of the [Formula: see text]-Au surface result in top layer Si atoms with an SiAu4 butterfly wing configuration. The structure of a [Formula: see text]-Au phase, whose in-plane top atomic layer positions were previously determined by an electron holography technique (Grozea et al 1998 Surf. Sci. 418 32), is calculated using total energy minimization. The Patterson function for this structure is calculated and is in good agreement with data from an in-plane x-ray diffraction study (Dornisch et al 1991 Phys. Rev. B 44 11221). Filled and empty state scanning tunneling microscopy (STM) images are calculated for domain walls and the [Formula: see text]-Au structure. The [Formula: see text]-Au phase is 2D chiral and this is evident in computed and actual STM images. [Formula: see text]-Au and domain wall structures contain the SiAu4 motif with a butterfly wing shape. Chemical bonding within the Si-Au top layers of the [Formula: see text]-Au and [Formula: see text]-Au surfaces is analyzed and an explanation for the SiAu4 motif structure is given. PMID

  4. Decomposition of dimethyl methylphosphonate on Pt, Au, and Au-Pt clusters supported on TiO2(110).

    PubMed

    Ratliff, Jay S; Tenney, Samuel A; Hu, Xiaofeng; Conner, Sean F; Ma, Shuguo; Chen, Donna A

    2009-01-01

    The decomposition of dimethyl methylphosphonate (DMMP) was studied by temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and Auger electron spectroscopy (AES) on TiO(2)-supported Pt, Au, and Au-Pt clusters as well as on TiO(2)(110) itself. In agreement with previous work, TPD experiments for DMMP on TiO(2)(110) showed that methyl and methane were the main gaseous products. Multiple DMMP adsorption-reaction cycles on TiO(2)(110) demonstrated that active sites for DMMP decomposition were blocked after a single cycle, but some activity for methyl production was sustained even after five cycles. Furthermore, the activity of the TiO(2) surface could be regenerated by heating in O(2) at 800 K or heating in vacuum to 965 K to remove surface carbon and phosphorus, which are byproducts of DMMP decomposition. On 0.5 ML Pt clusters deposited on TiO(2)(110), TPD studies of DMMP reaction showed that CO and H(2) were the main gas products, with methyl and methane as minor products. The Pt clusters were more active than TiO(2) both in terms of the total amount of DMMP reaction and the ability to break C-H, P-O, and P-OCH(3) bonds in DMMP. However, the Pt clusters had no sustained activity for DMMP decomposition, since the product yields dropped to zero after a single adsorption-reaction cycle. This loss of activity is attributed to a combination of poisoning of active sites by surface phosphorus species and encapsulation of the Pt clusters by reduced titania after heating above 600 K due to strong metal support interactions (SMSI). On 0.5 ML Au clusters, CO and H(2) were also the main products detected in TPD experiments, in addition to methane and methyl produced from reaction on the support. The Au clusters were less active for DMMP decomposition to CO and H(2) as well as P-O bond scission, but surface phosphorus was removed from the Au clusters by desorption at approximately 900 K. Au-Pt bimetallic clusters on TiO(2)(110) were prepared by

  5. Chlorine adsorption on Au(111): chlorine overlayer or surface chloride?

    PubMed

    Gao, Weiwei; Baker, Thomas A; Zhou, Ling; Pinnaduwage, Dilini S; Kaxiras, Efthimios; Friend, Cynthia M

    2008-03-19

    We report the first scanning tunneling microscope (STM) investigation, combined with density functional theory calculations, to resolve controversy regarding the bonding and structure of chlorine adsorbed on Au(111). STM experiments are carried out at 120 K to overcome instability caused by mobile species upon chlorine adsorption at room temperature. Chlorine adsorption initially lifts the herringbone reconstruction. At low coverages (<0.33 ML), chlorine binds to the top of Au(111)-(1 x 1) surface and leads to formation of an overlayer with (square root(3) x square root(3))R30 degree structure at 0.33 ML. At higher coverages, packing chlorine into an overlayer structure is no longer favored. Gold atoms incorporate into a complex superlattice of a Au-Cl surface compound. PMID:18290645

  6. Enhancing the reactivity of gold: Nanostructured Au(111) adsorbs CO

    DOE PAGESBeta

    Hoffmann, F. M.; Hrbek, J.; Ma, S.; Park, J. B.; Rodriguez, J. A.; Stacchiola, D. J.; Senanayake, S. D.

    2015-12-02

    Low-coordinated sites are surface defects whose presence can transform a surface of inert or noble metal such as Au into an active catalyst. We prepared gold surfaces modified by pits, starting with a well-ordered Au(111) surface; we then used microscopy (STM) for their structural characterization and CO spectroscopy (IRAS and NEXAFS) for probing reactivity of surface defects. In contrast to the Au(111) surface CO adsorbs readily on the pitted surfaces bonding to low-coordinated sites identified as step atoms forming {111} and {100} microfacets. Finally, pitted nanostructured surfaces can serve as interesting and easily prepared models of catalytic surfaces with definedmore » defects that offer an attractive alternative to vicinal surfaces or nanoparticles commonly employed in catalysis science.« less

  7. Plasmonic Fano resonances in compositional heterogenous Al- Au nanorod dimers

    NASA Astrophysics Data System (ADS)

    Wu, Botao; Xue, Yingxian; Ma, Qiang; Ding, Chengjie; Rong, Youying; Liu, Yan; Chen, Lingxiao; Wu, E.; Zeng, Heping

    2016-01-01

    We have investigated theoretically the plasmon resonance coupling in compositional heterogenous Al-Au nanorod dimers organized in a close proximity by end-to-end. It has been proved that the destructive interference between the bright dipole mode from Al nanorod and the dark quadrupole mode from Au nanorod nearby results in the appearance of apparent Fano resonance in the extinction spectra. The Fano resonance response on the structural dimension modifications in the proposed nanorod dimers have been estimated and determined. The Al-Au heterogeneous nanorod dimer shows a high sensitivity to the surrounding environment with a local surface plasmon resonance figure of merit of 7.6, which enables its promising applications in plasmonic sensing and detection.

  8. Growth and electronic properties of Ti nanoislands on Au(111)

    NASA Astrophysics Data System (ADS)

    Carrozzo, P.; Tumino, F.; Passoni, M.; Bottani, C. E.; Casari, C. S.; Li Bassi, A.

    2014-01-01

    The initial growth of titanium nanoislands on the reconstructed Au(111) surface was investigated by Scanning Tunneling Microscopy and Scanning Tunneling Spectroscopy (STM/STS). Ti atoms evaporated onto room temperature substrate start to nucleate preferentially at the elbows of the Au(111) herringbone reconstruction; however ordered nucleation is accompanied by an early occurrence of out-of-elbow islands. Titanium islands are irregularly shaped, composed of smaller sub-units as grains of about 1-2 nm2 and their growth leads to a distortion of the underlying gold surface. We observe a retarded coalescence of titanium first layer islands with respect to other similar systems. Comparing the experimental data with a diffusive model, quantitative information about the interlayer diffusion of the first two layers is obtained. STS spectra and differential conductivity maps show peculiar electronic features outlining an important interaction between Ti atoms and the Au(111) surface.

  9. Enhancing the reactivity of gold: Nanostructured Au(111) adsorbs CO

    NASA Astrophysics Data System (ADS)

    Hoffmann, F. M.; Hrbek, J.; Ma, S.; Park, J. B.; Rodriguez, J. A.; Stacchiola, D. J.; Senanayake, S. D.

    2016-08-01

    Low-coordinated sites are surface defects whose presence can transform a surface of inert or noble metal such as Au into an active catalyst. Starting with a well-ordered Au(111) surface we prepared by ion sputtering gold surfaces modified by pits, used microscopy (STM) for their structural characterization and CO spectroscopy (IRAS and NEXAFS) for probing reactivity of surface defects. In contrast to the Au(111) surface CO adsorbs readily on the pitted surfaces bonding to low-coordinated sites identified as step atoms forming {111} and {100} microfacets. Pitted nanostructured surfaces can serve as interesting and easily prepared models of catalytic surfaces with defined defects that offer an attractive alternative to vicinal surfaces or nanoparticles commonly employed in catalysis science.

  10. Au Nanowire-Striped Cu3P Platelet Photoelectrocatalysts.

    PubMed

    Dutta, Anirban; Samantara, Aneeya K; Adhikari, Samrat Das; Jena, Bikash Kumar; Pradhan, Narayan

    2016-03-17

    A stripy pattern of continuous epitaxial growth of thin Au nanowires on plasmonic Cu3P platelets is reported. The obtained Au-Cu3P heterostructures retain their wide area interfacial heterojunction, which is typically not observed in metal-semiconductor heterostructures. This is performed by phosphine-mediated in situ reduction of Au ions on specific facets of Cu3P platelets. The intriguing stripy movements of nanowires are regulated by strong surface binding ligands. Because this is a dual plasmon heterostructure with wide visible absorption window, these are further explored as a photoelectrocatalyst for efficient hole transfer and sensing of an important biomolecule, nicotinamide adenine dinucleotide (NADH). The observed anodic photocurrent was 30 times higher in the presence of NADH, and this proves that the heterostructured material is an ideal photosenser and an efficient catalyst for solar energy conversion. PMID:26938025

  11. Controlled electrodeposition of Au monolayer film on ionic liquid

    NASA Astrophysics Data System (ADS)

    Ma, Qiang; Pang, Liuqing; Li, Man; Zhang, Yunxia; Ren, Xianpei; Liu, Shengzhong Frank

    2016-05-01

    Gold (Au) nanoparticles have been attractive for centuries for their vibrant appearance enhanced by their interaction with sunlight. Nowadays, there have been tremendous research efforts to develop them for high-tech applications including therapeutic agents, sensors, organic photovoltaics, medical applications, electronics and catalysis. However, there remains to be a challenge to fabricate a monolayer Au coating with complete coverage in controlled fashion. Here we present a facile method to deposit a uniform Au monolayer (ML) film on the [BMIM][PF6] ionic liquid substrate using an electrochemical deposition process. It demonstrates that it is feasible to prepare a solid phase coating on the liquid-based substrate. Moreover, the thickness of the monolayer coating can be controlled to a layer-by-layer accuracy.

  12. Enhancing the reactivity of gold: Nanostructured Au(111) adsorbs CO

    SciTech Connect

    Hoffmann, F. M.; Hrbek, J.; Ma, S.; Park, J. B.; Rodriguez, J. A.; Stacchiola, D. J.; Senanayake, S. D.

    2015-12-02

    Low-coordinated sites are surface defects whose presence can transform a surface of inert or noble metal such as Au into an active catalyst. We prepared gold surfaces modified by pits, starting with a well-ordered Au(111) surface; we then used microscopy (STM) for their structural characterization and CO spectroscopy (IRAS and NEXAFS) for probing reactivity of surface defects. In contrast to the Au(111) surface CO adsorbs readily on the pitted surfaces bonding to low-coordinated sites identified as step atoms forming {111} and {100} microfacets. Finally, pitted nanostructured surfaces can serve as interesting and easily prepared models of catalytic surfaces with defined defects that offer an attractive alternative to vicinal surfaces or nanoparticles commonly employed in catalysis science.

  13. Fermi surfaces of surface states on Si(111)-Ag, Au

    NASA Astrophysics Data System (ADS)

    Crain, J. N.; Altmann, K. N.; Bromberger, C.; Himpsel, F. J.

    2002-11-01

    Metallic surface states on semiconducting substrates provide an opportunity to study low-dimensional electrons decoupled from the bulk. Angle resolved photoemission is used to determine the Fermi surface, group velocity, and effective mass for surface states on Si(111)(3)×(3)-Ag, Si(111)(3)×(3)-Au, and Si(111)(21)×(21)-(Ag+Au). For Si(111)(3)×(3)-Ag the Fermi surface consists of small electron pockets populated by electrons from a few % excess Ag. For Si(111)(21)×(21)-(Ag+Au) the pockets increase their size corresponding to a filling by three electrons per unit cell. The (21)×(21) superlattice leads to an intricate surface umklapp pattern and to minigaps of 110 meV, giving an interaction potential of 55 meV for the (21)×(21) superlattice.

  14. Electrical properties of AuN thin films

    NASA Astrophysics Data System (ADS)

    Quintero, J. H.; Ospina, R.; Cárdenas, O. O.; Alzate, G. I.; Devia, A.

    2008-10-01

    Gold nitride (AuN) is a recently synthesized component and is being studied for properties like optical, electrical and mechanical. Plasma-assisted physical vapor deposition (PAPVD) in pulsed arc system is used for deposition of AuN thin film. The system is formed of a reactor in which there are two faced electrodes, and a power-controlled system that performs the discharge systematically. Chemical analyses were realized by x-ray photoelectron spectroscopy (XPS) technique, and narrow N 1s and Au 4f spectra are shown using film stoichiometry, and I-V curves were obtained in two ways (substrate-film and film-substrate), to observe the electrical properties.

  15. Fabrication of Au/Ni Multilayered Nanowires by Electrochemical Deposition

    NASA Astrophysics Data System (ADS)

    Saidin, N. U.; Kok, K. Y.; Ng, I. K.; Ilias, S. H.

    2013-04-01

    Electrochemical deposition of Au/Ni multilayered nanowires using template-assisted growth technique from electrolyte containing nickel chloride and gold solution was studied in details. 60 μm-thick anodized aluminum oxide (AAO) with pore diameter of 200 nm was used as the template. Chronopotentiometry experiments were first carried out to determine the deposition conditions and the growth rate of individual Au and Ni layers. Scanning electron microscopy results revealed that the pore channels of AAO were completely filled with Au/Ni multisegmented nanowires. By selectively removing the Ni segments in the multilayered nanowires, high-yield of pure gold nanorods were obtained. Detailed studies on the nanostructures obtained were carried out using various microscopy and probe-based techniques for structural, morphological and chemical characterizations.

  16. Comparison of the Effects of Magnetic Field on Low Noise MoAu and TiAu TES Bolometers

    NASA Astrophysics Data System (ADS)

    Hijmering, R. A.; Khosropanah, P.; Ridder, M.; Gao, J. R.; Hoevers, H.; Jackson, B.; Goldie, D.; Withington, S.; Kozorezov, A. G.

    2014-08-01

    Recently we have reported on the effects of magnetic field on our low noise (NEP = 4 W/Hz) [1] TiAu TES bolometers that are being developed at SRON for the SAFARI FIR Imaging Spectrometer on SPICA telescope that will be operated in three different wavelength bands: S-band for 30-60 , M-band for 60-110 and L-band for 110-210 . The arrays for the S- and M- band will be based on TiAu TES bolometer arrays, developed by SRON. The L-band array will be based on a MoAu TES bolometer developed by University of Cambridge. We have investigated the effect of the magnetic field on the current, responsivity, speed and critical current for both the TiAu and MoAu TES bolometers in our high accuracy magnetic field set-up. A clear difference in weak link behavior is observed between the two types of TES bolometers in both strength of the effect and period of the oscillations.

  17. Measurement of direct photons in Au+Au collisions at √(s(NN))=200 GeV.

    PubMed

    Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Jamel, A; Alexander, J; Aoki, K; Aphecetche, L; Armendariz, R; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bauer, F; Bazilevsky, A; Belikov, S; Bennett, R; Berdnikov, Y; Bjorndal, M T; Boissevain, J G; Borel, H; Boyle, K; Brooks, M L; Brown, D S; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Campbell, S; Chai, J-S; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Chujo, T; Cianciolo, V; Cleven, C R; Cobigo, Y; Cole, B A; Comets, M P; Connors, M; Constantin, P; Csanád, M; Csörgő, T; Dahms, T; Das, K; David, G; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dietzsch, O; Dion, A; Drachenberg, J L; Drapier, O; Drees, A; Dubey, A K; Durum, A; Dzhordzhadze, V; Efremenko, Y V; Egdemir, J; Enokizono, A; En'yo, H; Espagnon, B; Esumi, S; Fields, D E; Fleuret, F; Fokin, S L; Forestier, B; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fukao, Y; Fung, S-Y; Gadrat, S; Gastineau, F; Germain, M; Glenn, A; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, M; Gunji, T; Gustafsson, H-Å; Hachiya, T; Hadj Henni, A; Haggerty, J S; Hagiwara, M N; Hamagaki, H; Harada, H; Hartouni, E P; Haruna, K; Harvey, M; Haslum, E; Hasuko, K; Hayano, R; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hiejima, H; Hill, J C; Hobbs, R; Holmes, M; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hur, M G; Ichihara, T; Iinuma, H; Imai, K; Imrek, J; Inaba, M; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Jacak, B V; Jia, J; Jin, J; Jinnouchi, O; Johnson, B M; Joo, K S; Jouan, D; Kajihara, F; Kametani, S; Kamihara, N; Kaneta, M; Kang, J H; Kawagishi, T; Kazantsev, A V; Kelly, S; Khanzadeev, A; Kim, D J; Kim, E; Kim, Y-S; Kinney, E; Kiss, A; Kistenev, E; Kiyomichi, A; Klein-Boesing, C; Kochenda, L; Kochetkov, V; Komkov, B; Konno, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kunde, G J; Kurihara, N; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lajoie, J G; Lebedev, A; Le Bornec, Y; Leckey, S; Lee, D M; Lee, M K; Leitch, M J; Leite, M A L; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Manko, V I; Masui, H; Matathias, F; McCain, M C; McGaughey, P L; Miake, Y; Miller, T E; Milov, A; Mioduszewski, S; Mishra, G C; Mitchell, J T; Morrison, D P; Moss, J M; Moukhanova, T V; Mukhopadhyay, D; Murata, J; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nakamura, T; Newby, J; Nguyen, M; Norman, B E; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Omiwade, O O; Oskarsson, A; Otterlund, I; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Park, W J; Pate, S F; Pei, H; Peng, J-C; Pereira, H; Peresedov, V; Peressounko, D Yu; Pinkenburg, C; Pisani, R P; Purschke, M L; Purwar, A K; Qu, H; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosendahl, S S E; Rosnet, P; Rukoyatkin, P; Rykov, V L; Ryu, S S; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, S; Samsonov, V; Sato, H D; Sato, S; Sawada, S; Semenov, V; Seto, R; Sharma, D; Shea, T K; Shein, I; Shibata, T-A; Shigaki, K; Shimomura, M; Shohjoh, T; Shoji, K; Sickles, A; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Skutnik, S; Smith, W C; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sullivan, J P; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Taketani, A; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Taranenko, A; Tarján, P; Thomas, T L; Togawa, M; Tojo, J; Torii, H; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Tuli, S K; Tydesjö, H; Tyurin, N; Vale, C; Valle, H; van Hecke, H W; Velkovska, J; Vértesi, R; Vinogradov, A A; Vznuzdaev, E; Wagner, M; Wang, X R; Watanabe, Y; Wessels, J; White, S N; Willis, N; Winter, D; Woody, C L; Wysocki, M; Xie, W; Yanovich, A; Yokkaichi, S; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zhang, C; Zimányi, J; Zolin, L

    2012-10-12

    We report the measurement of direct photons at midrapidity in Au+Au collisions at √(s(NN))=200 GeV. The direct photon signal was extracted for the transverse momentum range of 4 GeV/cAu+Au collision centralities using the measured p+p direct photon spectrum and compared to theoretical predictions. R(AA) was found to be consistent with unity for all centralities over the entire measured p(T) range. Theoretical models that account for modifications of initial direct photon production due to modified parton distribution functions in Au and the different isospin composition of the nuclei predict a modest change of R(AA) from unity. They are consistent with the data. Models with compensating effects of the quark-gluon plasma on high-energy photons, such as suppression of jet-fragmentation photons and induced-photon bremsstrahlung from partons traversing the medium, are also consistent with this measurement. PMID:23102300

  18. Influence of the S-Au Bond Strength on the Magnetic Behavior of S-Capped Au Nanoparticles

    NASA Astrophysics Data System (ADS)

    Vázquez, María J. Rodríguez; Rivas, José; López-Quintela, M. Arturo; Mosquera, Antonio Mouriño; Torneiro, Mercedes

    Recently, large permanent atomic magnetic moments have been found in Au nanoparticles capped with thiols. It is assumed that the formation of localized Au-S bonds at the particle surface induces the damping of the surface plasmon resonance and the appearance of a ferromagnetic-like behavior. In this work we will show for the first time that thioethers can also induce both phenomena, i.e., the damping of the plasmon band and the appearance of permanent magnetic moments. Furthermore, we have studied the influence of the Au-S bond strength on both phenomena using two different synthesized thioether ligands. It will be shown that, although both ligands can induce a complete damping of the plasmon band, only with one of the ligands (the one corresponding to the stronger S-Au bond) the appearance of a ferromagnetic-like order is observed. This is an indication of the extreme sensitivity of the magnetism on the strength of the charge transfer at the S-Au bond.

  19. Final Technical Report: First Principles Investigations for the Ensemble Effects of PdAu and PtAu Bimetallic Nanocatalysts

    SciTech Connect

    Ruqian Wu

    2012-05-18

    Bimetallic surfaces with tunable chemical properties have attracted broad attention in recent years due to their ample potential for heterogeneous catalysis applications. The local chemical properties of constituents are strongly altered from their parent metals by 'ligand effect', a term encompassing the influences of charge transfer, orbital rehybridization and lattice strain. In comparison to the aforementioned, the 'ensemble effect' associated with particular arrangements of the active constituents have received much less attention, despite their notable importance towards the determination of reactivity and selectivity of bimetallic catalysts. We performed theoretical studies for understanding the ensemble effects on bimetallic catalysis: (i) simulations for the formation of different ensembles on PdAu and PtAu nanoclusters; (ii) studies of the size, shape, and substrate dependence of their electronic properties; and (iii) simulations for model reactions such as CO oxidation, methanol, ethylene and water dehydrogenation on PdAu and PtAu nanoclusters. In close collaboration with leading experimental groups, our theoretical research elucidated the fundamentals of Au based bimetallic nanocatalysts.

  20. Common suppression pattern of eta and pi0 mesons at high transverse momentum in Au + Au collisions at square root S(NN) = 200 GeV.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; Chenawi, K El; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Perdekamp, M Grosse; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hiejima, H; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

    2006-05-26

    Inclusive transverse momentum spectra of eta mesons have been measured within p(T) = 2-10 GeV/c at midrapidity by the PHENIX experiment in Au + Au collisions at square root S(NN) = 200 GeV. In central Au+Au the eta yields are significantly suppressed compared to peripheral Au + Au, d + Au, and p + p yields scaled by the corresponding number of nucleon-nucleon collisions. The magnitude, centrality, and p(T) dependence of the suppression is common, within errors, for eta and pi0. The ratio of eta to pi0 spectra at high p(T) amounts to 0.40 < R(eta/pi)0 < 0.48 for the three systems, in agreement with the world average measured in hadronic and nuclear reactions and, at large scaled momentum, in e+e- collisions. PMID:16803168

  1. Compound formation and superconductivity in Au-Si: X-ray absorption measurements on ion-beam-mixed Au-Si films

    SciTech Connect

    Jeon, Y.; Jisrawi, N.; Liang, G.; Lu, F.; Croft, M.; McLean, W.L.; Hart, D.L.; Stoffel, N.G.; Sun, J.Z.; Geballe, T.H.; and others

    1989-03-15

    Multilayered Au-Si thin films have been deposited with the net compositions ''Au/sub 1-//sub x/Si/sub x/,'' x = 0.29, 0.5, and 0.8. After ion-beam mixing these films exhibited superconductivity in the 0.3--1.2 K range despite the nonsuperconducting character of both Au and Si. Near-edge x-ray absorption spectroscopy (XAS) measurements on the Au L/sub 3/ edge in these films indicate that metastable Au-Si compound formation occurs in these ion-mixed materials. Specifically, the XAS measurements indicate changes in Au 5d-orbital occupancy and changes in the local Au structural environment which are both consistent with local compound formation.

  2. Biogenic synthesis of Ag, Au and bimetallic Au/Ag alloy nanoparticles using aqueous extract of mahogany (Swietenia mahogani JACQ.) leaves.

    PubMed

    Mondal, Samiran; Roy, Nayan; Laskar, Rajibul A; Sk, Ismail; Basu, Saswati; Mandal, Debabrata; Begum, Naznin Ara

    2011-02-01

    In this paper, we have demonstrated for the first time, the superb efficiency of aqueous extract of dried leaves of mahogany (Swietenia mahogani JACQ.) in the rapid synthesis of stable monometallic Au and Ag nanoparticles and also Au/Ag bimetallic alloy nanoparticles having spectacular morphologies. Our method was clean, nontoxic and environment friendly. When exposed to aqueous mahogany leaf extract, competitive reduction of Au(III) and Ag(I) ions present simultaneously in same solution leads to the production of bimetallic Au/Ag alloy nanoparticles. UV-visible spectroscopy was used to monitor the kinetics of nanoparticles formation. UV-visible spectroscopic data and TEM images revealed the formation of bimetallic Au/Ag alloy nanoparticles. Mahogany leaf extract contains various polyhydroxy limonoids which are responsible for the reduction of Au(III) and Ag(I) ions leading to the formation and stabilization of Au and Ag nanopaticles. PMID:21030220

  3. The growth of sulfur adlayers on Au(100).

    PubMed

    Jiang, Yue; Liang, Xihui; Ren, Shendong; Chen, Chi-Lu; Fan, Liang-Jen; Yang, Yaw-Wen; Tang, Jian-Ming; Luh, Dah-An

    2015-02-14

    We have studied the growth of S layers adsorbed on Au(100) with low-energy electron diffraction (LEED), X-ray photoemission spectra (XPS), and scanning tunneling microscope (STM). Three phases of S/Au(100)-(2 × 2), trimer, and c(2 × 4)-are identified; the latter two are not previously reported. A dose of S2 at 300 K transformed Au(100)-(5 × 20) initially into the (2 × 2) phase and formed the c(2 × 4) phase at a saturation coverage. The STM results show that monolayer Au islands formed during the initial S dose and remained throughout the growth, resulting in a rough c(2 × 4) surface. We show that a highly ordered c(2 × 4) phase can be obtained with a flat (2 × 2) phase as an intermediate step during growth. Based on the evolution of XPS and STM images with varied S2 dose, the components of S 2p are assigned and structural models for the various S/Au(100) phases are proposed. In the (2 × 2) phase, one S atom resides on a four-fold hollow site in each (2 × 2) unit cell, corresponding to a S coverage of 0.25 ML; in the trimer phase, three S atoms form a trimer residing on a four-fold hollow site in each (2 × 2) unit cell, corresponding to a S coverage of 0.75 ML; in the c(2 × 4) phase, there are five S atoms in each primitive unit cell of c(2 × 4); three of them form a trimer residing on a four-fold hollow site, and the other two form a dimer located on the top of the trimer, corresponding to a nominal S coverage of 1.25 ML. With the proposed structural models, the growth of S on Au(100) at 300 K is described in detail. PMID:25681936

  4. The coupled geochemistry of Au and As in pyrite from hydrothermal ore deposits

    NASA Astrophysics Data System (ADS)

    Deditius, Artur P.; Reich, Martin; Kesler, Stephen E.; Utsunomiya, Satoshi; Chryssoulis, Stephen L.; Walshe, John; Ewing, Rodney C.

    2014-09-01

    The ubiquity of Au-bearing arsenian pyrite in hydrothermal ore deposits suggests that the coupled geochemical behaviour of Au and As in this sulfide occurs under a wide range of physico-chemical conditions. Despite significant advances in the last 20 years, fundamental factors controlling Au and As ratios in pyrite from ore deposits remain poorly known. Here we explore these constraints using new and previously published EMPA, LA-ICP-MS, SIMS, and μ-PIXE analyses of As and Au in pyrite from Carlin-type Au, epithermal Au, porphyry Cu, Cu-Au, and orogenic Au deposits, volcanogenic massive sulfide (VHMS), Witwatersrand Au, iron oxide copper gold (IOCG), and coal deposits. Pyrite included in the data compilation formed under temperatures from ∼30 to ∼600 °C and in a wide variety of geological environments. The pyrite Au-As data form a wedge-shaped zone in compositional space, and the fact that most data points plot below the solid solubility limit defined by Reich et al. (2005) indicate that Au1+ is the dominant form of Au in arsenian pyrite and that Au-bearing ore fluids that deposit this sulfide are mostly undersaturated with respect to native Au. The analytical data also show that the solid solubility limit of Au in arsenian pyrite defined by an Au/As ratio of 0.02 is independent of the geochemical environment of pyrite formation and rather depends on the crystal-chemical properties of pyrite and post-depositional alteration. Compilation of Au-As concentrations and formation temperatures for pyrite indicates that Au and As solubility in pyrite is retrograde; Au and As contents decrease as a function of increasing temperature from ∼200 to ∼500 °C. Based on these results, two major Au-As trends for Au-bearing arsenian pyrite from ore deposits are defined. One trend is formed by pyrites from Carlin-type and orogenic Au deposits where compositions are largely controlled by fluid-rock interactions and/or can be highly perturbed by changes in temperature and

  5. Reduced graphene oxide supported Au nanoparticles as an efficient catalyst for aerobic oxidation of benzyl alcohol

    NASA Astrophysics Data System (ADS)

    Yu, Xianqin; Huo, Yujia; Yang, Jing; Chang, Sujie; Ma, Yunsheng; Huang, Weixin

    2013-09-01

    Various Au/C catalysts were prepared by Au nanoparticels supported on different carbonaceous supports including reduced graphene oxide (RGO), activated carbon (AC) and graphite (GC) using sol-immobilization method. Au/RGO shows a much higher activity than Au/AC and Au/GC in the liquid phase aerobic oxidation of benzyl alcohol. The superior catalytic performance of Au/RGO may be related to the presence of surface O-containing functional groups and moderate graphite character of RGO supports.

  6. Enhanced electrochromic coloration of poly(3-hexylthiophene) films by electrodeposited Au nanoparticles.

    PubMed

    Nah, Yoon-Chae

    2013-05-01

    Au nanoparticles and poly(3-hexylthiophene) (P3HT) composite films were prepared by electrodeposition of Au nanoparticles using pulse-current electrodeposition followed by the spin coating of P3HT and their enhanced electrochromic coloration was investigated. A relatively uniformed Au nanoparticle was obtained by the controlled electrodeposition on indium tin oxide (ITO) substrate and plasmon absorption band of Au nanoparticles were observed. Optical and electrochemical properties of Au/P3HT composite films were compared with the pure P3HT films. The enhanced electrochromic absorption of the composite films was observed due to the surface plasmon resonance of the Au nanoparticles. PMID:23858881

  7. The effect of expressive and instrumental touch on the behavior states of older adults with late-stage dementia of the Alzheimer's type and on music therapist's perceived rapport.

    PubMed

    Belgrave, Melita

    2009-01-01

    The purpose of this study was to examine the effect of music therapy interventions utilizing two types of touch, expressive touch and instrumental touch, on the behavior states of older adults who have late-stage dementia of the Alzheimer's type. A secondary purpose of this study was to examine the perceived effectiveness of the music therapist when expressive and instrumental touch was employed during music therapy sessions. A within-subject design was used with 9 participants receiving 3 sessions in each of the experimental conditions: no touch, expressive touch, and instrumental touch. Results of a one-way ANOVA revealed that expressive touch was significantly more effective during the initial session in eliciting and maintaining alert behavior states than the instrumental and control conditions; however, there were no significant differences between the experimental and control conditions during the first and second session repetitions. Rapport ratings revealed that the therapist's client rapport was perceived to be significantly higher during both the expressive touch and instrumental touch conditions than during the control condition. These findings have important implications for music therapy practice and the effective use of nonverbal communication. PMID:19463031

  8. Atomic Structure of Au 329 (SR) 84 Faradaurate Plasmonic Nanomolecules

    SciTech Connect

    Kumara, Chanaka; Zuo, Xiaobing; Ilavsky, Jan; Cullen, David A.; Dass, Amala

    2015-05-21

    To design novel nanomaterials, it is important to precisely control the composition, determine the atomic structure, and manipulate the structure to tune the materials property. Here we present a comprehensive characterization of the material whose composition is Au329(SR)84 precisely, therefore referred to as a nanomolecule. The size homogeneity was shown by electron microscopy, solution X-ray scattering, and mass spectrometry. We proposed its atomic structure to contain the Au260 core using experiments and modeling of a total-scattering-based atomic-pair distribution functional analysis. HAADF- STEM images shows fcc-like 2.0 ± 0.1 nm diameter nanomolecules.

  9. Collisional modelling of the AU Microscopii debris disc

    NASA Astrophysics Data System (ADS)

    Schüppler, Ch.; Löhne, T.; Krivov, A. V.; Ertel, S.; Marshall, J. P.; Wolf, S.; Wyatt, M. C.; Augereau, J.-C.; Metchev, S. A.

    2015-09-01

    AU Microscopii's debris disc is one of the most famous and best-studied debris discs and one of only two resolved debris discs around M stars. We perform in-depth collisional modelling of the AU Mic disc including stellar radiative and corpuscular forces (stellar winds), aiming at a comprehensive understanding of the dust production and the dust and planetesimal dynamics in the system. Our models are compared to a suite of observational data for thermal and scattered light emission, ranging from the ALMA radial surface brightness profile at 1.3 mm to spatially resolved polarisation measurements in the visible. Most of the data are shown to be reproduced with dust production in a belt of planetesimals with an outer edge at around 40 au and subsequent inward transport of dust by stellar winds. A low dynamical excitation of the planetesimals with eccentricities up to 0.03 is preferred. The radial width of the planetesimal belt cannot be constrained tightly. Belts that are 5 au and 17 au wide, as well as a broad 44 au-wide belt, are consistent with observations. All models show surface density profiles that increase with distance from the star up to ≈40 au, as inferred from observations. The best model is achieved by assuming a stellar mass loss rate that exceeds the solar one by a factor of 50. The models reproduce the spectral energy distribution and the shape of the ALMA radial profile well, but deviate from the scattered light observations more strongly. The observations show a bluer disc colour and a lower degree of polarisation for projected distances <40 au than predicted by the models. These deviations may be reduced by taking irregularly shaped dust grains which have scattering properties different from the Mie spheres used in this work. From tests with a handful of selected dust materials, we favour mixtures of silicate, carbon, and ice of moderate porosity. We also address the origin of the unresolved central excess emission detected by ALMA and show that

  10. Atomic Structure of Au329(SR)84 Faradaurate Plasmonic Nanomolecules

    DOE PAGESBeta

    Kumara, Chanaka; Zuo, Xiaobing; Ilavsky, Jan; Cullen, David; Dass, Amala

    2015-04-03

    To design novel nanomaterials, it is important to precisely control the composition, determine the atomic structure, and manipulate the structure to tune the materials property. Here we present a comprehensive characterization of the material whose composition is Au329(SR)84 precisely, therefore referred to as a nanomolecule. The size homogeneity was shown by electron microscopy, solution X-ray scattering, and mass spectrometry. We proposed its atomic structure to contain the Au260 core using experiments and modeling of a total-scattering-based atomic-pair distribution functional analysis. HAADF-STEM images shows fcc-like 2.0 ± 0.1 nm diameter nanomolecules.

  11. Rational design and synthesis of excavated trioctahedral Au nanocrystals

    NASA Astrophysics Data System (ADS)

    Chen, Qiaoli; Jia, Yanyan; Shen, Wei; Xie, Shuifen; Yang, Yanan; Cao, Zhenming; Xie, Zhaoxiong; Zheng, Lansun

    2015-06-01

    Excavated polyhedral nanostructures, possessing the features of high surface area and well-defined surface structure with a specific crystal facet and avoidance of aggregation, could be one of the best choices for the purpose of reducing consumption and improving performance of noble metals in many application fields. However, the formation of the excavated structures is thermodynamically unfavourable and its rational synthesis is far beyond our knowledge. In this work, taking overgrowth of Pd onto trioctahedral Au nanocrystals as a model, we present a deep insight study for synthesizing an excavated structure relying on the protection role of surfactants under suitable crystal growth kinetics. Based on the abovementioned understanding, we designed a simple and effective strategy to synthesize Au nanocrystals with excavated trioctahedral structure in one step. Due to the novel feature of the excavated structure and exposed high energy {110} facets, excavated trioctahedral Au NCs exhibited optical extinction at the near-infrared region and showed high catalytic activity towards the reduction of p-nitrophenol. Moreover, the synthetic strategy can be extended to the synthesis of excavated Au-Pd alloys.Excavated polyhedral nanostructures, possessing the features of high surface area and well-defined surface structure with a specific crystal facet and avoidance of aggregation, could be one of the best choices for the purpose of reducing consumption and improving performance of noble metals in many application fields. However, the formation of the excavated structures is thermodynamically unfavourable and its rational synthesis is far beyond our knowledge. In this work, taking overgrowth of Pd onto trioctahedral Au nanocrystals as a model, we present a deep insight study for synthesizing an excavated structure relying on the protection role of surfactants under suitable crystal growth kinetics. Based on the abovementioned understanding, we designed a simple and effective

  12. Photocatalytic Au-Bi2S3 heteronanostructures.

    PubMed

    Manna, Goutam; Bose, Riya; Pradhan, Narayan

    2014-06-23

    Au-Bi2S3 heteronanostructure photocatalysts were designed in which the coupling of a metal plasmon and a semiconductor exciton aids the absorption of solar light, enhances charge separation, and results in improved catalytic activity. Furthermore, these nanostructures show a unique pattern of structural combination, with Au nanoparticles positioned at the center of Bi2S3 nanorods. The chemistry of formation of these nanostructures, their epitaxy at the junction, and their photoconductance were studied, as well as their photoresponse properties. PMID:24844409

  13. PtCo/Au nanocomposite: Synthesis, characterization, and magnetic properties

    NASA Astrophysics Data System (ADS)

    Dai, Jingtao; Du, Yukou; Wang, Fangwei; Yang, Ping

    2007-09-01

    Magnetic PtCo/Au nanocomposites with narrow size distribution were synthesized in a reverse micelle, followed by a post-synthesis handling of the stabilizer-exchange technique. The PtCo/Au nanocomposites were characterized by ultraviolet visible spectroscopy, X-ray diffraction and transmission electron microscopy, respectively. Superconducting quantum interference device studies revealed that the nanocomposites were superparamagnetic above the blocking temperature ( TB=69 K), while the samples were ferromagnetic with Hc (628 Oe) and Ms (2.97 emu /g) at 5 K.

  14. Nuclear Shadowing and Select d+Au Observables

    NASA Astrophysics Data System (ADS)

    Adeluyi, Adeola; Fai, George

    2007-04-01

    Much of the complexity of the description of d+Au collisions in the framework of perturbative Quantum Chromodynamics (pQCD) derives from effects of the nuclear environment. Here we investigate the effects of the most recent available nuclear shadowing parametrization, the Hirai-Kumano-Nagai (HKN) nuclear parton distribution functions (nPDFs) and the updated Albino-Kniehl-Kramer (AKK) fragmentation functions on three select d+Au collision observables. We compare our results to available experimental data from the STAR and BRAHMS collaborations.

  15. Graphene nanoribbons synthesized from molecular precursor polymerization on Au(110)

    SciTech Connect

    Massimi, Lorenzo; Ourdjini, Oualid; Della Pia, Ada; Mariani, Carlo; Betti, Maria Grazia; Cavaliere, Emanuele; Gavioli, Luca

    2015-06-23

    A spectroscopic study of 10,10-dibromo-9,9 bianthracene (DBBA) molecules deposited on the Au(110) surface is presented, by means of ultraviolet and X-ray photoemission, and X-ray absorption spectroscopy. Through a thermally activated procedure, these molecular precursors polymerize and eventually form graphene nanoribbons (GNRs) with atomically controlled shape and width, very important building blocks for several technological applications. The GNRs observed by scanning tunneling microscopy (STM) appear as short segments on top of the gold surface reconstruction, pointing out the delicate balance among surface diffusion and surface corrugation in their synthesis on the Au(110) surface.

  16. Nanoshells made easy: improving Au layer growth on nanoparticle surfaces.

    PubMed

    Brinson, Bruce E; Lassiter, J Britt; Levin, Carly S; Bardhan, Rizia; Mirin, Nikolay; Halas, Naomi J

    2008-12-16

    The growth of a continuous, uniform Au layer on a dielectric nanoparticle is the critical step in the synthesis of nanoparticles such as nanoshells or nanorice, giving rise to their unique geometry-dependent plasmon resonant properties. Here, we report a novel, streamlined method for Au layer metallization on prepared nanoparticle surfaces using carbon monoxide as the reducing agent. This approach consistently yields plasmonic nanoparticles with highly regular shell layers and is immune to variations in precursor or reagent preparation. Single particle spectroscopy combined with scanning electron microscopy reveal that thinner, more uniform shell layers with correspondingly red-shifted optical resonances are achievable with this approach. PMID:19360963

  17. Self-assembly of flagellin on Au(111) surfaces.

    PubMed

    González Orive, Alejandro; Pissinis, Diego E; Diaz, Carolina; Miñán, Alejandro; Benítez, Guillermo A; Rubert, Aldo; Daza Millone, Antonieta; Rumbo, Martin; Hernández Creus, Alberto; Salvarezza, Roberto C; Schilardi, Patricia L

    2014-11-01

    The adsorption of flagellin monomers from Pseudomonas fluorescens on Au(111) has been studied by Atomic Force Microscopy (AFM), Scanning Tunneling Microscopy (STM), X-ray Photoelectron Spectroscopy (XPS), Surface Plasmon Resonance (SPR), and electrochemical techniques. Results show that flagellin monomers spontaneously self-assemble forming a monolayer thick protein film bounded to the Au surface by the more hydrophobic subunit and exposed to the environment the hydrophilic subunit. The films are conductive and allow allocation of electrochemically active cytochrome C. The self-assembled films could be used as biological platforms to build 3D complex molecular structures on planar metal surfaces and to functionalize metal nanoparticles. PMID:25112916

  18. Substituent effects on charge transport in films of Au nanocrystals.

    PubMed

    Stansfield, Gemma L; Thomas, P John

    2012-07-25

    Charge transport (CT) in films of arylthiol-capped Au nanocrystals (NCs) exhibits strong substituent effects, with electron-donating substituents markedly decreasing conductivity. Films suited for measurements were obtained by ligand-exchange reactions on AuNCs grown at the water/toluene interface. Detailed analysis suggests the NCs interact with the ligands by resonance rather than inductive effects. The films were characterized by TEM, SEM, XPS, UV/vis, and AFM. CT characteristics were studied between 15 and 300 K. PMID:22746531

  19. Reliable methods for silica coating of Au nanoparticles.

    PubMed

    Pastoriza-Santos, Isabel; Liz-Marzán, Luis M

    2013-01-01

    The inherent properties of silica, such as optical transparency, high biocompatibility, chemical and colloidal stability, controllable porosity, and easy surface modification, provide silica materials with a tremendous potential in biomedicine. Therefore, the coating of Au nanoparticles with silica largely contributes to enhance the important applications of metal nanoparticles in biomedicine. We describe in this chapter a number of reliable strategies that have been reported for silica coating of different types of Au nanoparticles. All descriptions are based on tested protocols and are expected to provide a reference for scientists with an interest in this field. PMID:23918330

  20. Site-specific growth of Au-Pd alloy horns on Au nanorods: a platform for highly sensitive monitoring of catalytic reactions by surface enhancement Raman spectroscopy.

    PubMed

    Huang, Jianfeng; Zhu, Yihan; Lin, Ming; Wang, Qingxiao; Zhao, Lan; Yang, Yang; Yao, Ke Xin; Han, Yu

    2013-06-12

    Surface-enhanced Raman scattering (SERS) is a highly sensitive probe for molecular detection. The aim of this study was to develop an efficient platform for investigating the kinetics of catalytic reactions with SERS. To achieve this, we synthesized a novel Au-Pd bimetallic nanostructure (HIF-AuNR@AuPd) through site-specific epitaxial growth of Au-Pd alloy horns as catalytic sites at the ends of Au nanorods. Using high-resolution electron microscopy and tomography, we successfully reconstructed the complex three-dimensional morphology of HIF-AuNR@AuPd and identified that the horns are bound with high-index {11l} (0.25 < l < 0.43) facets. With an electron beam probe, we visualized the distribution of surface plasmon over the HIF-AuNR@AuPd nanorods, finding that strong longitudinal surface plasmon resonance concentrated at the rod ends. This unique crystal morphology led to the coupling of high catalytic activity with a strong SERS effect at the rod ends, making HIF-AuNR@AuPd an excellent bifunctional platform for in situ monitoring of surface catalytic reactions. Using the hydrogenation of 4-nitrothiophenol as a model reaction, we demonstrated that its first-order reaction kinetics could be accurately determined from this platform. Moreover, we clearly identified the superior catalytic activity of the rod ends relative to that of the rod bodies, owing to the different SERS activities at the two positions. In comparison with other reported Au-Pd bimetallic nanostructures, HIF-AuNR@AuPd offered both higher catalytic activity and greater detection sensitivity. PMID:23675958

  1. Gold chloride clusters with Au(III) and Au(I) probed by FT-ICR mass spectrometry and MP2 theory.

    PubMed

    Lemke, Kono H

    2014-05-01

    Microsolvated clusters of gold chloride are probed by electrospray ionization mass spectrometry (ESI-MS) and scalar relativistic electronic structure calculations. Electrospray ionization of aqueous AuCl3 leads to mononuclear clusters of types [AuCl2](+)(H2O)n (n = 0-4), [AuOHCl](+)(H2O)n (n = 0-1) and [AuCl2](+)(HCl)2(H2O)n (n = 0-4). In addition, strong ion signals due to dinuclear [Au2Cl5-xOHx](+)(H2O)n (x = 0-1) are present in ESI mass spectra of aqueous AuCl3, with the abundance of individual dinuclear species controlled by the concentration-dependent variation of the precursor complexes [AuCl2-xOHx](+)(H2O)n and AuCl3. Equilibrium structures, energies and thermodynamic properties of mono- and dinuclear gold clusters have been predicted using MP2 and CCSD(T) theory, and these data have been applied to examine the influence of microsolvation on cluster stability. Specifically, results from CCSD(T) calculations indicate that non-covalently bound ion-neutral complexes Au(+)(Cl2)(H2O)n, with formal Au(I), are the dominant forms of mononuclear gold with n = 0-2, while higher hydrates (n > 2) are covalently bound [AuCl2](+)(H2O)n complexes in which gold exists as Au(III). MP2 calculations show that the lowest energy structure of dinuclear gold is an ion-molecule cluster [Au2Cl(Cl2)2](+) consisting of a single-bridged digold-chloronium ion bound end-on to two dichlorine ligands, with two higher energy isomers, single-bridged [Au2Cl3(Cl2)](+) and double-bridged [Au2Cl5](+) clusters. Finally, AuAu interactions in the singly-bridged clusters [Au2Cl(Cl2)2](+)(H2O)n and [Au2Cl3(Cl2)](+)(H2O)n are examined employing a wide range of computational tools, including natural bond order (NBO) analysis and localized orbital locator (LOL) profiles. PMID:24643288

  2. Identification of the au coverage and structure of the Au/Si(111)-(5 × 2) surface.

    PubMed

    Kwon, Se Gab; Kang, Myung Ho

    2014-08-22

    We identify the atomic structure of the Au/Si(111)-(5 × 2) surface by using density functional theory calculations. With seven Au atoms per unit cell, our model forms a bona fide (5 × 2) atomic structure, which is energetically favored over the leading model of Erwin et al. [Phys. Rev. B 80, 155409 (2009)], and well reproduces the Y-shaped and V-shaped (5 × 2) STM images. This surface is metallic with a prominent half filled band of surface states, mostly localized around the Au-chain area. The correct identification of the atomic and band structure of the clean surface further clarifies the adsorption structure of Si adatoms and the physical origin of the intriguing metal-to-insulator transition driven by Si adatoms. PMID:25192108

  3. Synthesis and electrocatalytic activity of Au/Pt bimetallic nanodendrites for ethanol oxidation in alkaline medium.

    PubMed

    Han, Xinyi; Wang, Dawei; Liu, Dong; Huang, Jianshe; You, Tianyan

    2012-02-01

    Gold/Platinum (Au/Pt) bimetallic nanodendrites were successfully synthesized through seeded growth method using preformed Au nanodendrites as seeds and ascorbic acid as reductant. Cyclic voltammograms (CVs) of a series of Au/Pt nanodendrites modified electrodes in 1M KOH solution containing 1M ethanol showed that the electrocatalyst with a molar ratio (Au:Pt) of 3 exhibited the highest peak current density and the lowest onset potential. The peak current density of ethanol electro-oxidation on the Au(3)Pt(1) nanodendrites modified glassy carbon electrode (Au(3)Pt(1) electrode) is about 16, 12.5, and 4.5 times higher than those on the polycrystalline Pt electrode, polycrystalline Au electrode, and Au nanodendrites modified glassy carbon electrode (Au dendrites electrode), respectively. The oxidation peak potential of ethanol electro-oxidation on the Au(3)Pt(1) electrode is about 299 and 276 mV lower than those on the polycrystalline Au electrode and Au dendrites electrode, respectively. These results demonstrated that the Au/Pt bimetallic nanodendrites may find potential application in alkaline direct ethanol fuel cells (ADEFCs). PMID:22071516

  4. ΛΛ correlation function in Au + Au collisions at √sNN = 200 GeV

    SciTech Connect

    Adamczyk, L.

    2015-01-12

    In this study, we present ΛΛ correlation measurements in heavy-ion collisions for Au+Au collisions at √sNN = 200 GeV using the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). The Lednický-Lyuboshitz analytical model has been used to fit the data to obtain a source size, a scattering length and an effective range. Implications of the measurement of the ΛΛ correlation function and interaction parameters for di-hyperon searches are discussed.

  5. Forward-backward multiplicity correlations in sNN=200 GeV Au+Au collisions

    NASA Astrophysics Data System (ADS)

    Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Hauer, M.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Hołyński, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Noucier, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Seals, H.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; Nieuwenhuizen, G. J. Van; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

    2006-07-01

    Forward-backward correlations of charged-particle multiplicities in symmetric bins in pseudorapidity are studied to gain insight into the underlying correlation structure of particle production in Au+Au collisions. The PHOBOS detector is used to measure integrated multiplicities in bins centered at η, defined within |η|<3, and covering intervals Δη. The variance σC2 of a suitably defined forward-backward asymmetry variable C is calculated as a function of η,Δη, and centrality. It is found to be sensitive to short-range correlations, and the concept of “clustering” is used to interpret comparisons to phenomenological models.

  6. Enhancement of perpendicular magnetic anisotropy of Co layer in exchange-biased Au/Co/NiO/Au polycrystalline system

    NASA Astrophysics Data System (ADS)

    Kuświk, P.; Szymański, B.; Anastaziak, B.; Matczak, M.; Urbaniak, M.; Ehresmann, A.; Stobiecki, F.

    2016-06-01

    The perpendicular exchange bias in NiO(antiferromagnet)/Co(ferromagnet) polycrystalline layer films is studied. It is found that the NiO layer forces the Co layer magnetization to be oriented perpendicular to the film plane in a greater thickness range than is found in the Au/Co/Au system. Simultaneously, a large coercivity and a significant perpendicular exchange bias field were observed that are owing to the interlayer exchange bias coupling between NiO and Co, which supports the perpendicular magnetic anisotropy of the Co layer. These findings are confirmed by magnetometry and magnetoresistance measurements.

  7. Low frequency noise in the unstable contact region of Au-to-Au microcontact for microelectromechanical system switches

    SciTech Connect

    Qiu, Haodong; Wang, Hong; Ke, Feixiang

    2014-06-23

    The noise behavior of Au-to-Au microcontact for microelectromechanical system switches has been experimentally studied in the unstable contact region. The results suggest that the electrical conduction remains nonmetallic at the initial stage during contact formation due to the existence of alien films, and traps in the alien layer located at the contact interface could play an important role in determining the conduction noise. The conduction fluctuation induced by electron trapping-detrapping associated with the hydrocarbon layer is found to be an intrinsic noise source contributing to the low frequency noise in the unstable contact region.

  8. Au/(Ti-W) and Au/Cr metallization of chemically vapor-deposited diamond substrates for multichip module applications

    NASA Astrophysics Data System (ADS)

    Meyyappan, Ilango; Malshe, A. P.; Naseem, H. A.; Brown, W. D.

    1994-12-01

    Since diamond obtained by chemical vapor deposition (CVD) has an extremely high thermal conductivity, it holds great promise in solving thermal management problems in high performance multichip modules (MCMs). Consequently, there is a need to develop a reliable metallization system for CVD diamond. Refractory metals such as Ti, Mo, Ta and W are known to form adhering carbide layers at high temperatures. Also, transition metals such as Cr, Ni and Ni-Cr are widely used in other MCM technologies involving Si, AlN, SiC and alumina substrates. In the work reported here, adherent Au/Cr and Au/(Ti-W) metallization systems were produced at low temperatures using d.c. magnetron sputtering and electron beam evaporation techniques. Adhesion at low temperature is essential since CVD diamond could lose its thermal and electrical properties at high temperatures. Furthermore, interaction between metal layers may cause an increase in conductor trace resistivity and delamination. Adhesion was measured using a Sebastian V-A thin film stud pull tester. The deposition parameters were optimized to give maximum adhesion using a statistical design software package, echip. In the case of the sputtered metallization, pre-sputter cleaning of diamond surface improved adhesion significantly. Values above 9 klbf/sq in were obtained in the case of Au/(Ti-W) and 11.8 klbf/sq in in the case of Au/Cr. Post-deposition annealing was performed in nitrogen ambient to investigate the effect of post-metallization processing on adhesion and also to test for any possible interaction between the metals at high temperatures. Annealing temperatures were limited to 450 C since MCM substrates are seldom exposed to temperatures higher than these. Energy-dispersive spectroscopy (EDS) analysis indicated outdiffusion of W through Au at 400 deg C. No interdiffusion was observed in the case of Au/Cr as per optical microscopy and EDS analysis. Auger electron spectroscopy results indicate interaction between the

  9. Elliptic flow of identified hadrons in Au+Au collisions at sqrt sNN =200 GeV.

    PubMed

    Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; D'Enterria, D G; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, M; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, L D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'Brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V S; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zolin, L

    2003-10-31

    The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at sqrt[s(NN)]=200 GeV for identified and inclusive charged particle production at central rapidities (|eta|<0.35) with respect to the reaction plane defined at high rapidities (|eta|=3-4 ). We observe that the v(2) of mesons falls below that of (anti)baryons for p(T)>2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated. PMID:14611277

  10. V0 Reconstruction of Strange Hadrons in Au+Au Collisions at 1.23 AGeV with HADES

    NASA Astrophysics Data System (ADS)

    Scheib, T.; HADES Collaboration

    2015-04-01

    Preliminary results on the production of weakly decaying strange hadrons are reported for collisions of Au+Au at 1.23 AGeV beam energy studied with the HADES detector at GSI in Darmstadt. At this collision energy all strange particles are created below their elementary threshold. The reconstruction of the investigated particles (i.e. Λ and K0s) via the topology of their charged decay products (V0 reconstruction) is presented in detail. From the corrected yields of Λ and K0s the ratio K0S/Λ can be calculated and included into a statistical model fit.

  11. Elliptic flow due to charged hadrons for Au+Au collisions at RHIC energy 62.4 GeV

    NASA Astrophysics Data System (ADS)

    Kumar, Somani Ajit; Sudhir, Bhardwaj; Ashish, Agnihotri

    2016-05-01

    Elliptic flow is an important observable in search of Quark Gluon Plasma. The elliptic flow parameter dependence on centrality due to charged hadrons were studied using events generated by event generator AMPT at center of mass energy of 62.4 GeV per nucleon pair for Au+Au collisions. This study performed for pseudorapidity range from -0.35 to 0.35 and transverse momentum bins pt = 0.2 to 1 GeV/c and 1 to 2 GeV/c. We compared the results obtained from simulated data and RHIC-PHENIX data.

  12. Pion Interferometry of square root of (s(NN)) =130 GeV Au + Au collisions at RHIC.

    PubMed

    Adler, C; Ahammed, Z; Allgower, C; Amonett, J; Anderson, B D; Anderson, M; Averichev, G S; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bichsel, H; Bland, L C; Blyth, C O; Bonner, B E; Bossingham, R; Boucham, A; Brandin, A; Cadman, R V; Caines, H; Calderón De La Barca Sánchez, M; Cardenas, A; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chattopadhyay, S; Chen, M L; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Conin, L; Cormier, T M; Cramer, J G; Crawford, H J; DeMello, M; Deng, W S; Derevschikov, A A; Didenko, L; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Grabski, J; Grachov, O; Greiner, D; Grigoriev, V; Guedon, M; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Heffner, M; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Humanic, T J; Hümmler, H; Igo, G; Ishihara, A; Ivanshin, Y I; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E; Kaneta, M; Kaplan, M; Keane, D; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Konstantinov, A S; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kunde, G J; Kunz, C L; Kutuev, R K; Kuznetsov, A A; Lakehal-Ayat, L; Lamas-Valverde, J; Lamont, M A; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lebedev, A; LeCompte, T; Lednický, R; Leontiev, V M; LeVine, M J; Li, Q; Li, Q; Lindenbaum, S J; Lisa, M A; Ljubicic, T; Llope, W J; LoCurto, G; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Lynn, D; Majka, R; Margetis, S; Martin, L; Marx, J; Matis, H S; Matulenko, Y A; McShane, T S; Meissner, F; Melnick, Y; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mitchell, J; Moiseenko, V A; Moltz, D; Moore, C F; Morozov, V; de Moura, M M; Munhoz, M G; Mutchler, G S; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Pinganaud, W; Platner, E; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potrebenikova, E; Prindle, D; Pruneau, C; Radomski, S; Rai, G; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Roy, C; Russ, D; Rykov, V; Sakrejda, I; Sandweiss, J; Saulys, A C; Savin, I; Schambach, J; Scharenberg, R P; Schweda, K; Schmitz, N; Schroeder, L S; Schüttauf, A; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shestermanov, K E; Shimanskii, S S; Shvetcov, V S; Skoro, G; Smirnov, N; Snellings, R; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Stroebele, H; Struck, C; Suaide, A A; Sugarbaker, E; Suire, C; Sumbera, M; Symons, T J; Szanto De Toledo, A; Szarwas, P; Takahashi, J; Tang, A H; Thomas, J H; Tikhomirov, V; Trainor, T A; Trentalange, S; Tokarev, M; Tonjes, M B; Trofimov, V; Tsai, O; Turner, K; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vanyashin, A; Vasilevski, I M; Vasiliev, A N; Vigdor, S E; Voloshin, S A; Wang, F; Ward, H; Watson, J W; Wells, R; Wenaus, T; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Xu, N; Xu, Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yokosawa, A; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, W M; Zoulkarneev, R; Zubarev, A N

    2001-08-20

    Two-pion correlation functions in Au+Au collisions at square root of [s(NN)] = 130 GeV have been measured by the STAR (solenoidal tracker at RHIC) detector. The source size extracted by fitting the correlations grows with event multiplicity and decreases with transverse momentum. Anomalously large sizes or emission durations, which have been suggested as signals of quark-gluon plasma formation and rehadronization, are not observed. The Hanbury Brown-Twiss parameters display a weak energy dependence over a broad range in square root of [s(NN)]. PMID:11497937

  13. ΛΛ correlation function in Au + Au collisions at √sNN = 200 GeV

    DOE PAGESBeta

    Adamczyk, L.

    2015-01-12

    In this study, we present ΛΛ correlation measurements in heavy-ion collisions for Au+Au collisions at √sNN = 200 GeV using the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). The Lednický-Lyuboshitz analytical model has been used to fit the data to obtain a source size, a scattering length and an effective range. Implications of the measurement of the ΛΛ correlation function and interaction parameters for di-hyperon searches are discussed.

  14. Strong non-linear effects in the chiroptical properties of the ligand-exchanged Au38 and Au40 clusters

    NASA Astrophysics Data System (ADS)

    Knoppe, Stefan; Dass, Amala; Bürgi, Thomas

    2012-06-01

    Ligand exchange reactions on size-selected Au38(2-PET)24 and Au40(2-PET)24 clusters (2-PET: 2-phenylethylthiol) with mono- and bi-dentate chiral thiols were performed. The reactions were monitored with MALDI mass spectrometry and the arising chiroptical properties were compared to the number of incorporated chiral ligands. Only a small fraction of chiral ligands is needed to induce significant optical activity to the clusters. The use of bidentate 1,1'-binaphthyl-2,2'-dithiol (BINAS) leads to slow exchange, but the optical activity measured is strong. Moreover, a non-linear behaviour between optical activity and the number of chiral ligands is found in the BINAS case for both Au38 and Au40, which may indicate different exchange rates of enantiopure BINAS with the enantiomers of inherently chiral (but racemic) clusters. This is ascribed to effects arising from the bidentate nature of BINAS. In contrast, the use of monodentate camphor-10-thiol (CamSH) leads to comparably fast exchange on both clusters. The arising optical activity is weak. This is the first study where chiroptical effects are directly correlated with the composition of the ligand shell.Ligand exchange reactions on size-selected Au38(2-PET)24 and Au40(2-PET)24 clusters (2-PET: 2-phenylethylthiol) with mono- and bi-dentate chiral thiols were performed. The reactions were monitored with MALDI mass spectrometry and the arising chiroptical properties were compared to the number of incorporated chiral ligands. Only a small fraction of chiral ligands is needed to induce significant optical activity to the clusters. The use of bidentate 1,1'-binaphthyl-2,2'-dithiol (BINAS) leads to slow exchange, but the optical activity measured is strong. Moreover, a non-linear behaviour between optical activity and the number of chiral ligands is found in the BINAS case for both Au38 and Au40, which may indicate different exchange rates of enantiopure BINAS with the enantiomers of inherently chiral (but racemic) clusters

  15. Proton and pion production relative to the reaction plane in Au + Au collisions at 11A GeV/c

    SciTech Connect

    David, G.; Herrmann, N. |; Drigert, M.; Dai, Y.; Filimonov, K.; Clemen, M.; Chang, W.C.; Dee, J.; Hemmick, T.K.; Johnson, S.C. Dietzsch, O.; Cormier, T.M.; Hall, J.R.

    1997-12-01

    Results are presented of an analysis of proton and charged pion azimuthal distributions measured with respect to the reaction plane in Au + Au collisions at a beam momentum of about 11A GeV/c. The azimuthal anisotropy is studied as a function of particle rapidity and transverse momentum for different centralities of the collisions. The triple differential (in rapidity, transverse momentum, and azimuthal angle) distributions are reconstructed. A comparison of the results with a previous analysis of charged-particle and transverse energy flow as well as with model predictions are presented. {copyright} {ital 1997} {ital The American Physical Society}

  16. Measurement of inclusive antiprotons from Au+Au collisions at square root of s(NN) = 130 GeV.

    PubMed

    Adler, C; Ahammed, Z; Allgower, C; Amonett, J; Anderson, B D; Anderson, M; Averichev, G S; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellwied, R; Berger, J; Bichsel, H; Bland, L C; Blyth, C O; Bonner, B E; Boucham, A; Brandin, A; Cadman, R V; Caines, H; Calderón de la Barca Sánchez, M; Cardenas, A; Carroll, J; Castillo, J; Castro, M; Cebra, D; Chattopadhyay, S; Chen, M L; Chen, Y; Chernenko, S P; Cherney, M; Chikanian, A; Choi, B; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; DeMello, M; Deng, W S; Derevschikov, A A; Didenko, L; Draper, J E; Dunin, V B; Dunlop, J C; Eckardt, V; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Fachini, P; Faine, V; Filimonov, K; Finch, E; Fisyak, Y; Flierl, D; Foley, K J; Fu, J; Gagliardi, C A; Gagunashvili, N; Gans, J; Gaudichet, L; Germain, M; Geurts, F; Ghazikhanian, V; Grabski, J; Grachov, O; Grigoriev, V; Guedon, M; Gushin, E; Hallman, T J; Hardtke, D; Harris, J W; Heffner, M; Heppelmann, S; Herston, T; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Horsley, M; Huang, H Z; Humanic, T J; Hümmler, H; Igo, G; Ishihara, A; Ivanshin, Y I; Jacobs, P; Jacobs, W W; Janik, M; Johnson, I; Jones, P G; Judd, E; Kaneta, M; Kaplan, M; Keane, D; Kisiel, A; Klay, J; Klein, S R; Klyachko, A; Konstantinov, A S; Kotchenda, L; Kovalenko, A D; Kramer, M; Kravtsov, P; Krueger, K; Kuhn, C; Kulikov, A I; Kunde, G J; Kunz, C L; Kutuev, R K; Kuznetsov, A A; Lakehal-Ayat, L; Lamas-Valverde, J; Lamont, M A; Landgraf, J M; Lange, S; Lansdell, C P; Lasiuk, B; Laue, F; Lebedev, A; Lednický, R; Leontiev, V M; LeVine, M J; Li, Q; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, L; Liu, Z; Liu, Q J; Ljubicic, T; Llope, W J; LoCurto, G; Long, H; Longacre, R S; Lopez-Noriega, M; Love, W A; Lynn, D; Majka, R; Margetis, S; Martin, L; Marx, J; Matis, H S; Matulenko, Y A; McShane, T S; Meissner, F; Melnick, Y; Meschanin, A; Messer, M; Miller, M L; Milosevich, Z; Minaev, N G; Mitchell, J; Moiseenko, V A; Moore, C F; Morozov, V; de Moura, M M; Munhoz, M G; Mutchler, G S; Nelson, J M; Nevski, P; Nikitin, V A; Nogach, L V; Norman, B; Nurushev, S B; Odyniec, G; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Paic, G; Pandey, S U; Panebratsev, Y; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Perevoztchikov, V; Peryt, W; Petrov, V A; Platner, E; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potrebenikova, E; Prindle, D; Pruneau, C; Radomski, S; Rai, G; Ravel, O; Ray, R L; Razin, S V; Reichhold, D; Reid, J G; Retiere, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Roy, C; Rykov, V; Sakrejda, I; Sandweiss, J; Saulys, A C; Savin, I; Schambach, J; Scharenberg, R P; Schmitz, N; Schroeder, L S; Schüttauf, A; Schweda, K; Seger, J; Seliverstov, D; Seyboth, P; Shahaliev, E; Shestermanov, K E; Shimanskii, S S; Shvetcov, V S; Skoro, G; Smirnov, N; Snellings, R; Sowinski, J; Spinka, H M; Srivastava, B; Stephenson, E J; Stock, R; Stolpovsky, A; Strikhanov, M; Stringfellow, B; Struck, C; Suaide, A A; Sugarbaker, E; Suire, C; Sumbera, M; Symons, T J; de Toledo, A S; Szarwas, P; Takahashi, J; Tang, A H; Thomas, J H; Thompson, M; Tikhomirov, V; Trainor, T A; Trentalange, S; Tribble, R E; Tokarev, M; Tonjes, M B; Trofimov, V; Tsai, O; Turner, K; Ullrich, T; Underwood, D G; Van Buren, G; VanderMolen, A M; Vanyashin, A; Vasilevski, I M; Vasiliev, A N; Vigdor, S E; Voloshin, S A; Wang, F; Ward, H; Watson, J W; Wells, R; Wenaus, T; Westfall, G D; Whitten, C; Wieman, H; Willson, R; Wissink, S W; Witt, R; Xu, N; Xu, Z; Yakutin, A E; Yamamoto, E; Yang, J; Yepes, P; Yurevich, V I; Zanevski, Y V; Zborovský, I; Zhang, H; Zhang, W M; Zoulkarneev, R; Zubarev, A N

    2001-12-24

    We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions at square root of s(NN) = 130 GeV by the STAR experiment at RHIC. The antiproton transverse mass distributions in the measured transverse momentum range of 0.25

  17. Directed flow in Au+Au collisions at sNN=62.4 GeV

    NASA Astrophysics Data System (ADS)

    Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Badyal, S. K.; Bai, Y.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Bekele, S.; Belaga, V. V.; Bellingeri-Laurikainen, A.; Bellwied, R.; Berger, J.; Bezverkhny, B. I.; Bharadwaj, S.; Bhasin, A.; Bhati, A. K.; Bhatia, V. S.; Bichsel, H.; Bielcik, J.; Bielcikova, J.; Billmeier, A.; Bland, L. C.; Blyth, C. O.; Blyth, S.-L.; Bonner, B. E.; Botje, M.; Boucham, A.; Bouchet, J.; Brandin, A. V.; Bravar, A.; Bystersky, M.; Cadman, R. V.; Cai, X. Z.; Caines, H.; Sánchez, M. Calderón De La Barca; Castillo, J.; Catu, O.; Cebra, D.; Chajecki, Z.; Chaloupka, P.; Chattopadhyay, S.; Chen, H. F.; Chen, J. H.; Chen, Y.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, H. A.; Christie, W.; Coffin, J. P.; Cormier, T. M.; Cosentino, M. R.; Cramer, J. G.; Crawford, H. J.; Das, D.; Das, S.; Daugherity, M.; Moura, M. M. De; Dedovich, T. G.; Dephillips, M.; Derevschikov, A. A.; Didenko, L.; Dietel, T.; Dogra, S. M.; Dong, W. J.; Dong, X.; Draper, J. E.; Du, F.; Dubey, A. K.; Dunin, V. B.; Dunlop, J. C.; Mazumdar, M. R. Dutta; Eckardt, V.; Edwards, W. R.; Efimov, L. G.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Fachini, P.; Faivre, J.; Fatemi, R.; Fedorisin, J.; Filimonov, K.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Fornazier, K. S. F.; Fu, J.; Gagliardi, C. A.; Gaillard, L.; Gans, J.; Ganti, M. S.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gonzalez, J. E.; Gos, H.; Grachov, O.; Grebenyuk, O.; Grosnick, D.; Guertin, S. M.; Guo, Y.; Gupta, A.; Gupta, N.; Gutierrez, T. D.; Hallman, T. J.; Hamed, A.; Hardtke, D.; Harris, J. W.; Heinz, M.; Henry, T. W.; Hepplemann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffmann, G. W.; Horner, M. J.; Huang, H. Z.; Huang, S. L.; Hughes, E. W.; Humanic, T. J.; Igo, G.; Ishihara, A.; Jacobs, P.; Jacobs, W. W.; Jedynak, M.; Jiang, H.; Jones, P. G.; Judd, E. G.; Kabana, S.; Kang, K.; Kaplan, M.; Keane, D.; Kechechyan, A.; Khodyrev, V. Yu.; Kim, B. C.; Kiryluk, J.; Kisiel, A.; Kislov, E. M.; Klay, J.; Klein, S. R.; Koetke, D. D.; Kollegger, T.; Kopytine, M.; Kotchenda, L.; Kowalik, K. L.; Kramer, M.; Kravtsov, P.; Kravtsov, V. I.; Krueger, K.; Kuhn, C.; Kulikov, A. I.; Kumar, A.; Kutuev, R. Kh.; Kuznetsov, A. A.; Lamont, M. A. C.; Landgraf, J. M.; Lange, S.; Laue, F.; Lauret, J.; Lebedev, A.; Lednicky, R.; Lee, C.-H.; Lehocka, S.; Levine, M. J.; Li, C.; Li, Q.; Li, Y.; Lin, G.; Lindenbaum, S. J.; Lisa, M. A.; Liu, F.; Liu, H.; Liu, J.; Liu, L.; Liu, Q. J.; Liu, Z.; Ljubicic, T.; Llope, W. J.; Long, H.; Longacre, R. S.; Lopez-Noriega, M.; Love, W. A.; Lu, Y.; Ludlam, T.; Lynn, D.; Ma, G. L.; Ma, J. G.; Ma, Y. G.; Magestro, D.; Mahajan, S.; Mahapatra, D. P.; Majka, R.; Mangotra, L. K.; Manweiler, R.; Margetis, S.; Markert, C.; Martin, L.; Marx, J. N.; Matis, H. S.; Matulenko, Yu. A.; McClain, C. J.; McShane, T. S.; Meissner, F.; Melnick, Yu.; Meschanin, A.; Miller, M. L.; Minaev, N. G.; Mironov, C.; Mischke, A.; Mishra, D. K.; Mitchell, J.; Mohanty, B.; Molnar, L.; Moore, C. F.; Morozov, D. A.; Munhoz, M. G.; Nandi, B. K.; Nayak, S. K.; Nayak, T. K.; Nelson, J. M.; Netrakanti, P. K.; Nikitin, V. A.; Nogach, L. V.; Nurushev, S. B.; Odyniec, G.; Ogawa, A.; Okorokov, V.; Oldenburg, M.; Olson, D.; Pal, S. K.; Panebratsev, Y.; Panitkin, S. Y.; Pavlinov, A. I.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Petrov, V. A.; Phatak, S. C.; Picha, R.; Planinic, M.; Pluta, J.; Porile, N.; Porter, J.; Poskanzer, A. M.; Potekhin, M.; Potrebenikova, E.; Potukuchi, B. V. K. S.; Prindle, D.; Pruneau, C.; Putschke, J.; Rakness, G.; Raniwala, R.; Raniwala, S.; Ravel, O.; Ray, R. L.; Razin, S. V.; Reichhold, D.; Reid, J. G.; Reinnarth, J.; Renault, G.; Retiere, F.; Ridiger, A.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M. J.; Sahoo, R.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarsour, M.; Savin, I.; Sazhin, P. S.; Schambach, J.; Scharenberg, R. P.; Schmitz, N.; Schweda, K.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shahaliev, E.; Shao, M.; Shao, W.; Sharma, M.; Shen, W. Q.; Shestermanov, K. E.; Shimanskiy, S. S.; Sichtermann, E.; Simon, F.; Singaraju, R. N.; Smirnov, N.; Snellings, R.; Sood, G.; Sorensen, P.; Sowinski, J.; Speltz, J.; Spinka, H. M.; Srivastava, B.; Stadnik, A.; Stanislaus, T. D. S.; Stock, R.; Stolpovsky, A.; Strikhanov, M.; Stringfellow, B.; Suaide, A. A. P.; Sugarbaker, E.; Sumbera, M.; Surrow, B.; Swanger, M.; Symons, T. J. M.; Toledo, A. Szanto De; Tai, A.; Takahashi, J.; Tang, A. H.; Tarnowsky, T.; Thein, D.; Thomas, J. H.; Timmins, A. R.; Timoshenko, S.; Tokarev, M.; Trentalange, S.; Tribble, R. E.; Tsai, O. D.; Ulery, J.; Ullrich, T.; Underwood, D. G.; Buren, G. Van; Kolk, N. Van Der; Leeuwen, M. Van; Molen, A. M. Vander; Varma, R.; Vasilevski, I. M.; Vasiliev, A. N.; Vernet, R.; Vigdor, S. E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S. A.; Waggoner, W. T.; Wang, F.; Wang, G.; Wang, G.; Wang, X. L.; Wang, Y.; Wang, Y.; Wang, Z. M.; Ward, H.; Watson, J. W.; Webb, J. C.; Westfall, G. D.; Wetzler, A.; Whitten, C., Jr.; Wieman, H.; Wissink, S. W.; Witt, R.; Wood, J.; Wu, J.; Xu, N.; Xu, Z.; Xu, Z. Z.; Yamamoto, E.; Yepes, P.; Yoo, I.-K.; Yurevich, V. I.; Zborovsky, I.; Zhang, H.; Zhang, W. M.; Zhang, Y.; Zhang, Z. P.; Zhong, C.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zubarev, A. N.; Zuo, J. X.

    2006-03-01

    We present the directed flow (v1) measured in Au+Au collisions at sNN=62.4 GeV in the midpseudorapidity region |η|<1.3 and in the forward pseudorapidity region 2.5<|η|<4.0. The results are obtained using the three-particle cumulant method, the event plane method with mixed harmonics, and for the first time at the Relativistic Heavy Ion Collider, the standard method with the event plane reconstructed from spectator neutrons. Results from all three methods are in good agreement. Over the pseudorapidity range studied, charged particle directed flow is in the direction opposite to that of fragmentation neutrons.

  18. Global transverse energy distributions in Si+Al, Au at 14.6 A GeV/ c and Au+Au at 11.6 A GeV/ c

    NASA Astrophysics Data System (ADS)

    Ahle, L.; Akiba, Y.; Beavis, D.; Britt, H. C.; Budick, B.; Chasman, C.; Chen, Z.; Chi, C. Y.; Chu, Y. Y.; Cianciolo, V.; Cole, B. A.; Costales, J. B.; Crawford, H. J.; Cumming, J. B.; Debbe, R.; Engelage, J.; Fung, S. Y.; Gonin, M.; Gushue, S.; Hamagaki, H.; Hansen, O.; Hayano, R. S.; Hayashi, S.; Homma, S.; Kaneko, H.; Kang, J.; Kaufman, S.; Kehoe, W. L.; Kurita, K.; LeVine, M. J.; Miake, Y.; Morrison, D. P.; Moskowitz, B.; Nagamiya, S.; Namboodiri, M. N.; Nayak, T. K.; Olness, J.; Remsberg, L. P.; Rothschild, P.; Sangster, T. C.; Seto, R.; Shigaki, K.; Soltz, R.; Steadman, S. G.; Stephans, G. S. F.; Sung, T.; Tannenbaum, M. J.; Thomas, J.; Tonse, S.; Ueno, S.; van Dijk, J. H.; Videbaek, F.; Vossnack, O.; Wang, F. Q.; Wang, Y.; Wegner, H. E.; Woodruff, D. S.; Wu, Y. D.; Yagi, K.; Yang, X.; Zachary, D.; Zajc, W. A.; E-802 Collaboration

    1994-07-01

    Measurements of the global transverse energy distributions dσ/ dET and dET/ dη using the new AGS beam of 197Au at 11.6 A GeV/ c on a Au target, as well as a beam of 28Si at 14.6 A GeV/ c on Al and Au targets, are presented for a leadglass detector with acceptance 1.3 ≤ η ≤ 2.4 and 0 ≤ φ < 2 π. The dσ/ dET spectra are observed to have different shapes for the different systems and simple energy rescaling does not account for the projectile dependence. The Au+Au dσ/ dET spectrum is satisfactorily constructed from the upper edge of Si+Au by the geometric Wounded Projectile Nucleon Model after applying a correction for the beam energy.

  19. Understanding the effect of ultrathin AuPd alloy shells of irregularly shaped Au@AuPd nanoparticles with high-index facets on enhanced performance of ethanol oxidation

    NASA Astrophysics Data System (ADS)

    Bi, Cuixia; Feng, Cong; Miao, Tingting; Song, Yahui; Wang, Dayang; Xia, Haibing

    2015-11-01

    In this study, irregularly shaped, concave cuboidal Au@AuPd nanoparticles (ISCC-Au@AuPd NPs) with high-index facets were synthesized via Pd overgrowth on pre-formed ISCC-Au NPs with a concentration of Pd precursors as low as 2%. The AuPd alloy nature of the resulting shells was confirmed by X-ray photoelectron spectroscopy, cyclic voltammogram analysis, and energy dispersive X-ray spectroscopy. Among the irregularly shaped NPs obtained, the ISCC-Au97.5@Au0.5Pd2.0 NPs display the largest electrochemically active surface area (up to 92.11 m2 g-1), as their closed-packed agglomeration was prevented, and the best long-term stability with respect to ethanol oxidation (0.50 M) in alkaline media (0.30 KOH) by efficiently removing intermediates. Their mass- and ECSA-normalized current densities (4.15 A mgPd-1 and 4.51 mA cm-2) are about 20.7 times and 6.9 times higher than those of commercial Pd/C catalysts (0.20 A mgPd-1 and 0.65 mA cm-2), respectively.In this study, irregularly shaped, concave cuboidal Au@AuPd nanoparticles (ISCC-Au@AuPd NPs) with high-index facets were synthesized via Pd overgrowth on pre-formed ISCC-Au NPs with a concentration of Pd precursors as low as 2%. The AuPd alloy nature of the resulting shells was confirmed by X-ray photoelectron spectroscopy, cyclic voltammogram analysis, and energy dispersive X-ray spectroscopy. Among the irregularly shaped NPs obtained, the ISCC-Au97.5@Au0.5Pd2.0 NPs display the largest electrochemically active surface area (up to 92.11 m2 g-1), as their closed-packed agglomeration was prevented, and the best long-term stability with respect to ethanol oxidation (0.50 M) in alkaline media (0.30 KOH) by efficiently removing intermediates. Their mass- and ECSA-normalized current densities (4.15 A mgPd-1 and 4.51 mA cm-2) are about 20.7 times and 6.9 times higher than those of commercial Pd/C catalysts (0.20 A mgPd-1 and 0.65 mA cm-2), respectively. Electronic supplementary information (ESI) available: High magnification TEM

  20. Photoreduction of Au(III) to form Au(0) nanoparticles using ferritin as a photocatalyst

    NASA Astrophysics Data System (ADS)

    Hilton, Robert J.; Keyes, Jeremiah D.; Watt, Richard K.

    2010-04-01

    Gold metal nanoparticles have applications in bio sensing technology, nano-tube formation, and cancer therapy. We report attempts to synthesize gold nanoparticles within the ferritin cavity (8 nm) or to use ferritin as a scaffold for coating gold on the outside surface (12 nm). The intrinsic iron oxide core of ferritin is a semi-conductor and light can excite electrons to a conduction band producing a powerful reductant when a sacrificial electron donor fills the electron hole. We present a method using ferritin to photo chemically reduce Au(III) to metallic gold nanoparticles. During initial studies we observed that the choice of buffers influenced the products that formed as evidenced by a red product formed in TRIS and a purple produce formed in MOPS. Gold nanoparticles formed in MOPS buffer in the absence of illumination have diameters of 15-30 nm whereas illumination in TRIS buffer produced 5-10 nm gold nanoparticles. Increases in temperature cause the gold nanoparticles to form more rapidly. Chemical reduction and photochemical reduction methods have very different reaction profiles with photochemical reduction possessing a lag phase prior to the formation of gold nanoparticles.

  1. Chemical stability and degradation mechanisms of triangular Ag, Ag@Au, and Au nanoprisms.

    PubMed

    Lee, Kee Eun; Hesketh, Amelia V; Kelly, Timothy L

    2014-06-28

    Anisotropic metal nanoparticles have found use in a variety of plasmonic applications because of the large near-field enhancements associated with them; however, the very features that give rise to these enhancements (e.g., sharply curved edges and tips) often have high surface energies and are easily degraded. This paper describes the stability and degradation mechanisms of triangular silver, gold-coated silver, and gold nanoprisms upon exposure to a wide variety of adverse conditions, including halide ions, thiols, amines and elevated temperatures. The silver nanoprisms were immediately and irreversibly degraded under all of the conditions studied. In contrast, the core-shell Ag@Au nanoprisms were less susceptible to etching by chlorides and bromides, but were rapidly degraded by iodides, amines and thiols by a different degradation pathway. Only the pure gold nanoprisms were stable to all of the conditions tested. These results have important implications for the suitability of triangular nanoprisms in many applications; this is particularly true in biological or environmental fields, where the nanoparticles would inevitably be exposed to a wide variety of chemical stimuli. PMID:24827005

  2. Selective Hydrogenation of Acetylene over Pd, Au, and PdAu Supported Nanoparticles

    NASA Astrophysics Data System (ADS)

    Walker, Michael P.

    The removal of trace amounts of acetylene in ethylene streams is a high-volume industrial process that must possess high selectivity of alkyne hydrogenation over hydrogenation of alkenes. Current technology uses metallic nanoparticles, typically palladium or platinum, for acetylene removal. However, problems arise due to the deactivation of the catalysts at high temperatures as well as low selectivities at high conversions. Pore expanded MCM-41 is synthesized via a two-step strategy in which MCM-41 was prepared via cetyltrimethylammonium bromide (CTMABr) followed by the hydrothermal treatment with N,N-dimethyldecylamine (DMDA). This material was washed with ethanol to remove DMDA, or calcined to remove both surfactants. PE-MCM-41 based materials were impregnated with palladium, gold, and palladium-gold nanoparticles. The removal of DMDA had an effect on both the conversion and selectivity, in which they were found to drop significantly. However, by using the bimetallic PdAu catalysts, higher selectivity could be achieved due to increased electron density.

  3. Nitrogen mineralization from 'AU Golden' sunn hemp residue

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The tropical legume sunn hemp (Crotalaria juncea) cultivar ‘AU Golden’ has the potential to provide substantial amounts of nitrogen (N) to subsequent crops that could reduce recommended application rates of synthetic N fertilizers. Nitrogen fertilization problems via legumes are often due to asynch...

  4. Electrochemical functionalization of Au by aminobenzene and 2-aminotoluene.

    PubMed

    Rösicke, F; Sun, G; Neubert, T; Janietz, S; Hinrichs, K; Rappich, J

    2016-03-01

    Au surfaces are functionalized by aminobenzene (AB) and 2-aminotoluene (AT) using the electrochemical reduction of diazotized 1,4-diaminobenzene and 2,5-diaminotoluene. The IR spectroscopic measurements reveal the successful modification of Au surfaces by AB and AT. Both types of layers show similar thicknesses as obtained by microgravimetric measurements via electrochemical quartz crystal microbalance (EQCM). However, the faradaic efficiency for the grafting of AT onto an EQCM-Au sensor was 6% compared to 41% for the grafting of AB. This behavior points to a steric hindrance during the binding of AT to the EQCM surface induced by the additional methyl group present in the toluene derivative. The AB and AT functionalized surfaces have been further modified by the amidation reaction of EDC/NHS activated 4-nitrobenzoic acid. This model system reveals that the amidation reaction is slightly hindered in case of the AT layer due to the presence of the methyl group close to the amino group. This behavior leads to a four times less amount of amide bonds at the AT compared to AB modified Au surfaces as obtained from IR spectroscopic measurements. PMID:26872104

  5. The Structure of Dithiol Monolayers on Au(111).

    NASA Astrophysics Data System (ADS)

    Gallagher, M. C.; Macdairmid, A. R.; Banks, J. T.

    2003-03-01

    Using scanning tunneling microscopy (STM), Auger electron spectroscopy (AES), and contact angle measurements, we have studied the properties of Dithiothreitol (DTT) and Dithioerythritol (DTE) monolayers adsorbed on Au(111). DTT and DTE are both O-H functionalized α - ω dithiols. DTT is a chiral form whereas DTE is achiral. For comparison we have also studied the structure of octanethiol (n-alkanethiol, n = 8) SAMs. Octanethiol forms the characteristic close packed 3x3 monolayer with c(4x2) superstructure. In contrast, STM measurements of DTT films indicate much of the layer is disordered, however regions with local c(23x3) symmetry are observed. AES indicates the sulphur coverage for both DTT and octanethiol films are similar. AES studies involving Ellman's reagent, a marker species, also suggest a significant fraction of the DTT molecules in the adlayer bind to the gold via two Au-S bonds. Based on these results, we propose a structural model in which the majority of DTT molecules bind to the gold surface via two Au-S bonds and the distance between these two bonds is 3 times the underlying Au lattice spacing. Any differences between DTT and DTE layers due to differences in molecular structure will also be discussed.

  6. Vacuum level alignment of pentacene on LiF/Au

    NASA Astrophysics Data System (ADS)

    Watkins, N. J.; Gao, Y.

    2003-07-01

    We examined the interfaces of pentacene on LiF/Au substrates as a function of LiF thickness. We found that, regardless of the thickness of LiF, upon pentacene deposition onto LiF, the pentacene vacuum level aligns with that of LiF. We also show that LiF exhibits an interface dipole when deposited onto Au and that the magnitude of the interface dipole increases as the LiF thickness increases. The change in vacuum level as a function of LiF thickness allows the Fermi level position within the band gap of pentacene to be moved from 0.5 eV above the highest occupied molecular orbital to 2.1 eV above the highest occupied molecular orbital. This produces a hole injection barrier of 0.5 eV at the pentacene/Au interface and an electron injection barrier of 0.1 eV at the pentacene/40-Å-LiF/Au interface.

  7. Au/Si Nanorod-Based Biosensor for Salmonella Detection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among several potentials of nanotechnology applications for food industry, development of nanoscale sensors for food safety and quality measurement are emerging. A novel biosensor for Salmonella detection was developed using Au/Si/ nanorods. The Si nanorods were fabricated by glancing angle depositi...

  8. Superconductivity in uranium compounds with Cu3Au structure

    NASA Astrophysics Data System (ADS)

    Ott, H. R.; Hulliger, F.; Rudigier, H.; Fisk, Z.

    1985-02-01

    Superconductivity has been observed in uranium compounds with partly disordered Cu3Au-type crystal structure and interatomic U-U distances of more than 4 Å. Low-temperature specific-heat experiments reveal no anomalous enhancement of the electronic specific heat thus distinguishing the present materials from the unconventional superconductors UBe13 and UPt3.

  9. Investigation of Metal Free Naphthalocyanine Vapor Deposited on Au(111)

    SciTech Connect

    Wiggins, Bryan C.; Hipps, Kerry W.

    2014-02-27

    Naphthalocyanines (Ncs) are promising candidates for future components in electronic devices and applications. To maximize the efficiency of Nc devices, it is critical to understand their structural and electronic properties and how these are impacted by deposition methods. The formation of a metal free naphthalocyanine (H2Nc) self-assembled monolayer on a Au(111) crystal was investigated by scanning tunneling microscopy under ultra-high-vacuum conditions at room temperature. A rigorous purification and processing procedure was developed to produce high purity, low defect, and well-ordered monolayers. High-resolution STM images reveal epitaxial growth of H2Nc on Au(111) with the observed structure having a molecular spacing of 1.6 ± 0.05 nm, with molecules orientated slightly off (roughly 2.5°) the low density packing direction of Au(111). A commensurate structure having 4 molecules per unit cell and unit cell parameters of A = 3.25 ± 0.05 nm, B = 3.17 ± 0.05 nm, and α = 87.5 ± 2° is proposed. Orbital-mediated tunneling spectroscopy was used to examine the electronic properties of individual molecules within the thin film. The first ionization potential and electron affinity of H2Nc adsorbed on Au(111) were measured to be -0.68 ± 0.03 and 1.12 ± 0.02 eV, relative to the Fermi energy.

  10. Au nanoparticles improve amorphous carbon to be gas sensors

    NASA Astrophysics Data System (ADS)

    Liu, Keng-Wen; Lee, Jian-Heng; Chou, Hsiung; Lin, Tzu-Ching; Lin, Si-Ting; Shih-Jye Sun Collaboration

    In order to make the amorphous carbon possess the gas sensing capability transferring some sp3 orbits to sp2 is necessary. It is proposed that the metallic materials having a large charge exchange with sp3 carbon orbits are being catalysts to transfer the carbon orbits. We found embedding gold nanoparticles to the amorphous carbon will induce many compact sp2 orbits around the nanoparticles, which make the amorphous carbon be the candidate material for the gas sensors. The orbits of amorphous carbon near the interface of Au nanoparticles can be changed from sp3 to compact sp2 to reduce the surface energy of Au nanoparticles. Meanwhile, our molecular dynamics simulation has confirmed the fact, when an Au nanoparticle is embedded in the amorphous carbon system the ratio of sp2 orbits increases dramatically. Similar results also have been confirmed from the Raman spectrum measurements. We controlled the carrier transport by changing the hopping barriers formed by amorphous carbon matrix between the Au nanoparticles to modify the resistance. These nanocomposites exhibit a superior sensitivity to NH3 at room temperature as well as good reproducibility and short response/recovery times, which could have potential applications in gas sensors. Dept. of Applied Physics,NUK, Kaohsiung, Taiwan.

  11. Electrochemical functionalization of Au by aminobenzene and 2-aminotoluene

    NASA Astrophysics Data System (ADS)

    Rösicke, F.; Sun, G.; Neubert, T.; Janietz, S.; Hinrichs, K.; Rappich, J.

    2016-03-01

    Au surfaces are functionalized by aminobenzene (AB) and 2-aminotoluene (AT) using the electrochemical reduction of diazotized 1,4-diaminobenzene and 2,5-diaminotoluene. The IR spectroscopic measurements reveal the successful modification of Au surfaces by AB and AT. Both types of layers show similar thicknesses as obtained by microgravimetric measurements via electrochemical quartz crystal microbalance (EQCM). However, the faradaic efficiency for the grafting of AT onto an EQCM-Au sensor was 6% compared to 41% for the grafting of AB. This behavior points to a steric hindrance during the binding of AT to the EQCM surface induced by the additional methyl group present in the toluene derivative. The AB and AT functionalized surfaces have been further modified by the amidation reaction of EDC/NHS activated 4-nitrobenzoic acid. This model system reveals that the amidation reaction is slightly hindered in case of the AT layer due to the presence of the methyl group close to the amino group. This behavior leads to a four times less amount of amide bonds at the AT compared to AB modified Au surfaces as obtained from IR spectroscopic measurements.

  12. Templated Control of Au nanospheres in Silica Nanowires

    SciTech Connect

    Tringe, J W; Vanamu, G; Zaidi, S H

    2007-03-15

    The formation of regularly-spaced metal nanostructures in selectively-placed insulating nanowires is an important step toward realization of a wide range of nano-scale electronic and opto-electronic devices. Here we report templated synthesis of Au nanospheres embedded in silica nanowires, with nanospheres consistently spaced with a period equal to three times their diameter. Under appropriate conditions, nanowires form exclusively on Si nanostructures because of enhanced local oxidation and reduced melting temperatures relative to templates with larger dimensions. We explain the spacing of the nanospheres with a general model based on a vapor-liquid-solid mechanism, in which an Au/Si alloy dendrite remains liquid in the nanotube until a critical Si concentration is achieved locally by silicon oxide-generated nanowire growth. Additional Si oxidation then locally reduces the surface energy of the Au-rich alloy by creating a new surface with minimum area inside of the nanotube. The isolated liquid domain subsequently evolves to become an Au nanosphere, and the process is repeated.

  13. Vacuum synthesis of magnetic aluminum phthalocyanine on Au(111).

    PubMed

    Hong, I-Po; Li, Na; Zhang, Ya-Jie; Wang, Hao; Song, Huan-Jun; Bai, Mei-Lin; Zhou, Xiong; Li, Jian-Long; Gu, Gao-Chen; Zhang, Xue; Chen, Min; Gottfried, J Michael; Wang, Dong; Lü, Jing-Tao; Peng, Lian-Mao; Hou, Shi-Min; Berndt, Richard; Wu, Kai; Wang, Yong-Feng

    2016-08-16

    Air-unstable magnetic aluminum phthalocyanine (AlPc) molecules are prepared by an on-surface metalation reaction of phthalocyanine with aluminum (Al) atoms on Au(111) in ultrahigh vacuum. Experiments and density functional theory calculations show that an unpaired spin is located on the conjugated isoindole lobes of the molecule rather than at the Al position. PMID:27406881

  14. XANES and EXAFS study of Au-substituted YBa2Cu3O(7-delta)

    NASA Technical Reports Server (NTRS)

    Ruckman, Mark W.; Hepp, Aloysius F.

    1990-01-01

    The near-edge structure (XANES) of the Au L3 and Cu K edges of YBa2Au(0.3)Cu(2.7)O(7-delta) was studied. X ray diffraction suggests that Au goes on the Cu(1) site and XANES shows that this has little effect on the oxidation state of the remaining copper. The gold L3 edge develops a white line feature whose position lies between that of trivalent gold oxide (Au2O3) and monovalent potassium gold cyanide (KAu(CN)2) and whose intensity relative to the edge step is smaller than in the two reference compounds. The L3 EXAFS for Au in the superconductor resembles that of Au2O3. However, differences in the envelope of the Fourier filtered component for the first shell suggest that the local structure of the Au in the superconductor is not equivalent to Au2O3.

  15. Coverage-dependent geometries of nanowires on Ge(0 0 1)-Au surfaces: modification of trenches.

    PubMed

    Seino, Kaori; Bechstedt, Friedhelm

    2016-07-20

    Despite intense research the microscopic atomic structure of Au-induced nanowires on Ge(0 0 1) substrates is still under discussion. We analyse a variety of structural models for Au-induced nanowires on the Ge(0 0 1) surface using first-principles calculations. Here we focus on subridge modifications at higher Au coverages and study geometries based on the giant missing row model with Ge-Ge dimers in the grooves between the nanowires due to replacing them by Ge-Au heterodimers or Au-Au homodimers. Stable geometries are predicted for higher Au coverages, which however have only a minor influence on the electronic structure. The findings are interpreted that the Au coverage and the actual geometry may vary in the various experiments according to the preparation conditions. PMID:27227337

  16. Au 4f spin-orbit coupling effects in supported gold nanoparticles.

    PubMed

    Chenakin, Sergey P; Kruse, Norbert

    2016-08-17

    Using X-ray photoelectron spectroscopy we examine the Au 4f spin-orbit components in Au 4f spectra of nanosized Au particles on a TiO2 support. In general, the peak ratios of the Au 4f7/2 and 4f5/2 excitations are found to deviate from the statistical ratio of 4 : 3 and their linewidths (FWHM) are not equal. We reveal that both the FWHM and the Au 4f7/2-to-4f5/2 peak ratios increase appreciably as the Au atomic concentration on the surface of the TiO2 support and the size of Au nanoparticles decrease. On the contrary, the Au 4f spin-orbit splitting remains essentially unchanged. Our findings are discussed in terms of alterations in the electronic band structure. PMID:27480507

  17. AuRu/AC as an effective catalyst for hydrogenation reactions

    DOE PAGESBeta

    Villa, Alberto; Chan-Thaw, Carine E.; Campisi, Sebastiano; Bianchi, Claudia L.; Wang, Di; Kotula, Paul G.; Kübel, Christian; Prati, Laura

    2015-03-23

    AuRu bimetallic catalysts have been prepared by sequential deposition of Au on Ru or vice versa obtaining different nanostructures: when Ru has been deposited on Au, a Aucore–Rushell has been observed, whereas the deposition of Au on Ru leads to a bimetallic phase with Ru enrichment on the surface. In the latter case, the unexpected Ru enrichment could be attributed to the weak adhesion of Ru on the carbon support, thus allowing Ru particles to diffuse on Au particles. Both structures result very active in catalysing the liquid phase hydrogenolysis of glycerol and levulinic acid but the activity, the selectivitymore » and the stability depend on the structure of the bimetallic nanoparticles. Ru@Au/AC core–shell structure mostly behaved as the monometallic Ru, whereas the presence of bimetallic AuRu phase in Au@Ru/AC provides a great beneficial effect on both activity and stability.« less

  18. Doping golden clusters: MAu-19 and M2Au-18 (M = Cu and Na)

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Fa, Wei

    2012-04-01

    The structural and electronic properties of MAu-19 and M2Au-18 (M = Cu and Na) have been studied by the relativistic density-functional calculations. It is found that the most stable configurations of CuAu-19 and Cu2Au-18 are the face-centered and two-face-centered doped structures based upon the tetrahedral structure Au-20. In contrast, the ground states of Na-doped gold clusters (NaAu-19 and Na2Au-18) exhibit flat-cage configurations. The PES of these ground states are depicted that may be helpful to identify their configurations in