Nucleon shadowing effects in Cu + Cu and Au + Au collisions at RHIC within the HIJING code

NASA Astrophysics Data System (ADS)

Abdel-Waged, Khaled; Felemban, Nuha

2018-02-01

The centrality dependence of pseudorapidity density of charged particles ({{{d}}{N}}{{ch}}/{{d}}η ) in Cu + Cu (Au + Au) collisions at Relativistic Heavy Ion Collider energy of \\sqrt{{s}{{NN}}}=22.4, 62.4 and 200 (19.6, 62.4 and 200) GeV, is investigated within an improved HIJING code. The standard HIJING model is enhanced by a prescription for collective nucleon-nucleon (NN) interactions and more modern parton distribution functions. The collective NN-interactions are used to induce both cascade and nucleon shadowing effects. We find collective cascade broadens the pseudorapidity distributions in the tails (at | η | > {y}{beam}) above 25%-30% collision centrality to be consistent with the {{{d}}{N}}{{ch}}/{{d}}η data at \\sqrt{{s}{{NN}}} =19.6,22.4,62.4 {GeV}. The overall contribution of nucleon shadowing is shown to depress the whole shape of {{{d}}{N}}{{ch}}/{{d}}η in the primary interaction region (at | η | < {y}{beam}) for semiperipheral (20%-25%) and peripheral (≥slant 35 % {--}40 % ) Cu + Cu (Au + Au) interactions at \\sqrt{{s}{{NN}}}=200 {GeV}, in accordance with the PHOBOS data.

Systematic study of azimuthal anisotropy in Cu + Cu and Au + Au collisions at √{sNN}=62.4 and 200 GeV

NASA Astrophysics Data System (ADS)

Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Al-Bataineh, H.; Al-Jamel, A.; Alexander, J.; Aoki, K.; Aphecetche, L.; Armendariz, R.; Aronson, S. H.; Asai, J.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Baksay, G.; Baksay, L.; 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.; Bickley, A. A.; 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.; Chang, B. S.; Charvet, J.-L.; Chernichenko, S.; Chi, C. Y.; Chiba, J.; Chiu, M.; Choi, I. J.; Chujo, T.; Chung, P.; Churyn, A.; Cianciolo, V.; Cleven, C. R.; Cobigo, Y.; Cole, B. A.; Comets, M. P.; Constantin, P.; Csanád, M.; Csörgő, T.; Dahms, T.; Das, K.; David, G.; Deaton, M. B.; Dehmelt, K.; Delagrange, H.; Denisov, A.; D'Enterria, D.; Deshpande, A.; Desmond, E. J.; Dietzsch, O.; Dion, A.; Donadelli, M.; Drachenberg, J. L.; Drapier, O.; Drees, A.; Dubey, A. K.; Durum, A.; Dzhordzhadze, V.; Efremenko, Y. V.; Egdemir, J.; Ellinghaus, F.; Emam, W. S.; Enokizono, A.; En'yo, H.; Espagnon, B.; Esumi, S.; Eyser, K. O.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Forestier, B.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fung, S.-Y.; Fusayasu, T.; Gadrat, S.; Garishvili, I.; Gastineau, F.; Germain, M.; Glenn, A.; Gong, H.; 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.; Haegemann, C.; Haggerty, J. S.; Hagiwara, M. N.; Hamagaki, H.; Han, R.; Harada, H.; Hartouni, E. P.; Haruna, K.; Harvey, M.; Haslum, E.; Hasuko, K.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Heuser, J. M.; Hiejima, H.; Hill, J. C.; Hobbs, R.; Hohlmann, M.; Holmes, M.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hornback, D.; Huang, S.; Hur, M. G.; Ichihara, T.; Iinuma, H.; Imai, K.; Inaba, M.; Inoue, Y.; 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.; Kamin, J.; Kaneta, M.; Kang, J. H.; Kanou, H.; Kawagishi, T.; Kawall, D.; Kazantsev, A. V.; Kelly, S.; Khanzadeev, A.; Kikuchi, J.; Kim, D. H.; Kim, D. J.; Kim, E.; Kim, Y.-S.; Kinney, E.; Kiss, Á.; Kistenev, E.; Kiyomichi, A.; Klay, J.; Klein-Boesing, C.; Kochenda, L.; Kochetkov, V.; Komkov, B.; Konno, M.; Kotchetkov, D.; Kozlov, A.; Král, A.; Kravitz, A.; Kroon, P. J.; Kubart, J.; Kunde, G. J.; Kurihara, N.; Kurita, K.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Le Bornec, Y.; Leckey, S.; Lee, D. M.; Lee, M. K.; Lee, T.; Leitch, M. J.; Leite, M. A. L.; Lenzi, B.; Li, X.; Li, X. H.; Lim, H.; Liška, T.; Litvinenko, A.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Malakhov, A.; Malik, M. D.; Manko, V. I.; Mao, Y.; Mašek, L.; Masui, H.; Matathias, F.; McCain, M. C.; McCumber, M.; McGaughey, P. L.; Miake, Y.; Mikeš, P.; Miki, K.; Miller, T. E.; Milov, A.; Mioduszewski, S.; Mishra, G. C.; Mishra, M.; Mitchell, J. T.; Mitrovski, M.; Morreale, A.; Morrison, D. P.; Moss, J. M.; Moukhanova, T. V.; Mukhopadhyay, D.; Murata, J.; Nagamiya, S.; Nagata, Y.; Nagle, J. L.; Naglis, M.; Nakagawa, I.; Nakamiya, Y.; Nakamura, T.; Nakano, K.; Newby, J.; Nguyen, M.; Norman, B. E.; Nouicer, R.; Nyanin, A. S.; Nystrand, J.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Ohnishi, H.; Ojha, I. D.; Oka, M.; Okada, K.; Omiwade, O. O.; Oskarsson, A.; Otterlund, I.; Ouchida, M.; 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.; Rakotozafindrabe, A.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; 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.; Sakata, H.; Samsonov, V.; Sato, H. D.; Sato, S.; Sawada, S.; Seele, J.; Seidl, R.; Semenov, V.; Seto, R.; Sharma, D.; Shea, T. K.; Shein, I.; Shevel, A.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shohjoh, T.; Shoji, K.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, C. P.; Singh, V.; Skutnik, S.; Slunečka, M.; 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.; Todoroki, T.; Togawa, M.; Toia, A.; Tojo, J.; Tomášek, L.; 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.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wagner, M.; Walker, D.; Wang, X. R.; Watanabe, Y.; Wessels, J.; White, S. N.; Willis, N.; Winter, D.; Woody, C. L.; Wysocki, M.; Xie, W.; Yamaguchi, Y. L.; Yanovich, A.; Yasin, Z.; Ying, J.; Yokkaichi, S.; Young, G. R.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zaudtke, O.; Zhang, C.; Zhou, S.; Zimányi, J.; Zolin, L.; Phenix Collaboration

2015-09-01

We have studied the dependence of azimuthal anisotropy v2 for inclusive and identified charged hadrons in Au +Au and Cu +Cu collisions on collision energy, species, and centrality. The values of v2 as a function of transverse momentum pT and centrality in Au +Au collisions at √{s NN}=200 and 62.4 GeV are the same within uncertainties. However, in Cu +Cu collisions we observe a decrease in v2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au +Au and Cu +Cu collisions we find that v2 depends both on eccentricity and the number of participants, Npart. We observe that v2 divided by eccentricity (ɛ ) monotonically increases with Npart and scales as Npart1 /3. The Cu +Cu data at 62.4 GeV falls below the other scaled v2 data. For identified hadrons, v2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy K ET=mT-m between 0.1 Cu +Cu data at 62.4 GeV, of v2/(nq.ɛ .Npart1 /3) vs K ET/nq for all measured particles.

Systematic study of azimuthal anisotropy in Cu + Cu and Au + Au collisions at √s NN = 62.4 and 200 GeV

DOE PAGES

Adare, A.

2015-09-23

We have studied the dependence of azimuthal anisotropy v 2 for inclusive and identified charged hadrons in Au+Au and Cu+Cu collisions on collision energy, species, and centrality. The values of v 2 as a function of transverse momentum pT and centrality in Au+Au collisions at √s NN=200 and 62.4 GeV are the same within uncertainties. However, in Cu+Cu collisions we observe a decrease in v 2 values as the collision energy is reduced from 200 to 62.4 GeV. The decrease is larger in the more peripheral collisions. By examining both Au+Au and Cu+Cu collisions we find that v 2 dependsmore » both on eccentricity and the number of participants, N part. We observe that v 2 divided by eccentricity (ε) monotonically increases with N part and scales as N 1/3 part. Thus, the Cu+Cu data at 62.4 GeV falls below the other scaled v 2 data. For identified hadrons, v 2 divided by the number of constituent quarks nq is independent of hadron species as a function of transverse kinetic energy KE T=m T–m between 0.1T/n q<1 GeV. Combining all of the above scaling and normalizations, we observe a near-universal scaling, with the exception of the Cu+Cu data at 62.4 GeV, of v 2/(n q∙ε∙N 1/3 part) vs KE T/n q for all measured particles.« less

Dual structural transition in small nanoparticles of Cu-Au alloy

NASA Astrophysics Data System (ADS)

Gafner, Yuri; Gafner, Svetlana; Redel, Larisa; Zamulin, Ivan

2018-02-01

Cu-Au alloy nanoparticles are known to be widely used in the catalysis of various chemical reactions as it was experimentally defined that in many cases the partial substitution of copper with gold increases catalytic activity. However, providing the reaction capacity of alloy nanoparticles the surface electronic structure strongly depends on their atomic ordering. Therefore, to theoretically determine catalytic properties, one needs to use a most real structural model complying with Cu-Au nanoparticles under various external influences. So, thermal stability limits were studied for the initial L12 phase in Cu3Au nanoalloy clusters up to 8.0 nm and Cu-Au clusters up to 3.0 nm at various degrees of Au atom concentration, with molecular dynamics method using a modified tight-binding TB-SMA potential. Dual structural transition L12 → FCC and further FCC → Ih is shown to be possible under the thermal factor in Cu3Au and Cu-Au clusters with the diameter up to 3.0 nm. The temperature of the structural transition FCC → Ih is established to decrease for small particles of Cu-Au alloy under the increase of Au atom concentration. For clusters with this structural transition, the melting point is found to be a linear increasing function of concentration, and for clusters without FCC → Ih structural transition, the melting point is a linear decreasing function of Au content. Thus, the article shows that doping Cu nanoclusters with Au atoms allows to control the forming structure as well as the melting point.

U-Pb, Re-Os and Ar-Ar dating of the Linghou polymetallic deposit, Southeastern China: Implications for metallogenesis of the Qingzhou-Hangzhou metallogenic belt

NASA Astrophysics Data System (ADS)

Tang, Yanwen; Xie, Yuling; Liu, Liang; Lan, Tingguan; Yang, Jianling; Sebastien, Meffre; Yin, Rongchao; Liang, Songsong; Zhou, Limin

2017-04-01

The Qingzhou-Hangzhou metallogenic belt (QHMB) in Southeastern China has gained increasingly attention in recent years. However, due to the lack of reliable ages on intrusions and associated deposits in this belt, the tectonic setting and metallogenesis of the QHMB have not been well understood. The Linghou polymetallic deposit in northwestern Zhejiang Province is one of the typical deposits of the QHMB. According to the field relationships, this deposit consists of the early Cu-Au-Ag and the late Pb-Zn-Cu mineralization stages. Molybdenite samples with a mineral assemblage of molybdenite-chalcopyrite-pyrite ± quartz are collected from the copper mining tunnel near the Cu-Au-Ag ore bodies. Six molybdenite samples give the Re-Os model ages varying from 160.3 to 164.1 Ma and yield a mean age of 162.2 ± 1.4 Ma for the Cu-Au-Ag mineralization. Hydrothermal muscovite gives a well-defined Ar-Ar isochron age of 160.2 ± 1.1 Ma for the Pb-Zn-Cu mineralization. Three phases of granodioritic porphyry have been distinguished in this deposit, and LA-ICP-MS zircon U-Pb dating shows that they have formed at 158.8 ± 2.4 Ma, 158.3 ± 1.9 Ma and 160.6 ± 2.1 Ma, comparable to the obtained ages of the Cu-Au-Ag and Pb-Zn-Cu mineralization. Therefore, these intrusive rocks have a close temporal and spatial relationship with the Cu-Au-Ag and Pb-Zn-Cu ore bodies. The presences of skarn minerals (e.g., garnet) and vein-type ores, together with the previous fluid inclusion and H-O-C-S-Pb isotopic data, clearly indicate that the Cu-Au-Ag and Pb-Zn-Cu mineralization are genetically related to these granodiorite porphyries. This conclusion excludes the possibility that this deposit is of ;SEDEX; type and formed in a sag basin of continental rifts setting as previously proposed. Instead, it is proposed that the Linghou polymetallic and other similar deposits in the QHMB, such as the 150-160 Ma Yongping porphyry-skarn Cu-Mo, Dongxiang porphyry? Cu, Shuikoushan/Kangjiawang skarn Pb

Indium-bearing sulfides from the Hämmerlein skarn deposit, Erzgebirge, Germany: evidence for late-stage diffusion of indium into sphalerite

NASA Astrophysics Data System (ADS)

Bauer, Matthias E.; Seifert, Thomas; Burisch, Mathias; Krause, Joachim; Richter, Nancy; Gutzmer, Jens

2017-12-01

At the Hämmerlein skarn deposit, located in the western Erzgebirge (Germany), a major cassiterite-dominated Sn mineralization stage is spatially associated with a younger Zn-Cu-In sulfide mineralization stage. In this contribution, we provide the first detailed description of the Zn-Cu-In sulfide mineralization stage, based on field geological observations combined with detailed petrographic studies and electron probe microanalysis data. Indium-rich sulfide mineralization occurs as irregular, semi-massive lenses or as infill of short, discontinuous veinlets that crosscut the cassiterite-bearing skarn assemblage. Indium- and Cu-rich sphalerite and roquesite are found to be closely associated with In-bearing chalcopyrite. The highest In concentrations in sphalerite occur at the rims and along cracks of sphalerite grains. The distribution resembles diffusion profiles, suggesting that the In enrichment is due to an hydrothermal overprint that postdates the initial formation of both sphalerite and chalcopyrite. Textural relations illustrate that the diffusion fronts in sphalerite grains are thicker where they are in contact to anhedral masses of hematite and magnetite. Our observations suggest that In enrichment in sphalerite at the Hämmerlein skarn deposit is due to the decomposition of In-bearing chalcopyrite. The resultant release of Fe led to the formation of hematite and magnetite, whereas Cu and In were incorporated into sphalerite along grain boundaries and micro fractures. Incorporation into the sphalerite lattice took place by coupled substitution of Cu+ + In3+ ↔ 2Zn2+, suggesting that the concurrent availability of Cu and In may be an essential factor to enrich In in sphalerite in hydrothermal ore-forming environments.

Enhanced catalyst activity by decorating of Au on Ag@Cu2O nanoshell

NASA Astrophysics Data System (ADS)

Chen, Lei; Liu, Maomao; Zhao, Yue; Kou, Qiangwei; Wang, Yaxin; Liu, Yang; Zhang, Yongjun; Yang, Jinghai; Jung, Young Mee

2018-03-01

We successfully synthesized Au-decorated Ag@Cu2O heterostructures via a simple galvanic replacement method. As the Au precursor concentration increased, the density of the Au nanoparticles (NPs) on the Ag@Cu2O surface increased, which changed the catalytic activity of the Ag@Cu2O-Au structure. The combination of Au, Ag, and Cu2O exhibited excellent catalytic properties, which can further effect on the catalyst activity of the Ag@Cu2O-Au structure. In addition, the proposed Ag@Cu2O-Au nanocomposite was used to transform the organic, toxic pollutant, 4-nitrophenol (4-NP), into its nontoxic and medicinally important amino derivative via a catalytic reduction to optimize the material performance. The proposed Au-decorated Ag@Cu2O exhibited excellent catalytic activity, and the catalytic reduction time greatly decreased (5 min). Thus, three novel properties of Ag@Cu2O-Au, i.e., charge redistribution and transfer, adsorption, and catalytic reduction of organic pollutants, were ascertained for water remediation. The proposed catalytic properties have potential applications for photocatalysis and localized surface plasmon resonance (LSPR)- and peroxidase-like catalysis.

Crystal Structural Effect of AuCu Alloy Nanoparticles on Catalytic CO Oxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhan, Wangcheng; Wang, Jinglin; Wang, Haifeng

2017-06-07

Controlling the physical and chemical properties of alloy nanoparticles (NPs) is an important approach to optimize NP catalysis. Unlike other tuning knobs, such as size, shape, and composition, crystal structure has received limited attention and not been well understood for its role in catalysis. This deficiency is mainly due to the difficulty in synthesis and fine-tuning of the NPs’ crystal structure. Here, Exemplifying by AuCu alloy NPs with face centered cubic (fcc) and face centered tetragonal (fct) structure, we demonstrate a remarkable difference in phase segregation and catalytic performance depending on the crystal structure. During the thermal treatment in air,more » the Cu component in fcc-AuCu alloy NPs segregates more easily onto the alloy surface as compared to that in fct-AuCu alloy NPs. As a result, after annealing at 250 °C in air for 1 h, the fcc- and fct-AuCu alloy NPs are phase transferred into Au/CuO and AuCu/CuO core/shell structures, respectively. More importantly, this variation in heterostructures introduces a significant difference in CO adsorption on two catalysts, leading to a largely enhanced catalytic activity of AuCu/CuO NP catalyst for CO oxidation. Furthermore, the same concept can be extended to other alloy NPs, making it possible to fine-tune NP catalysis for many different chemical reactions.« less

Corrosion resistance evaluation of Pd-free Ag-Au-Pt-Cu dental alloys.

PubMed

Fujita, Takeshi; Shiraishi, Takanobu; Takuma, Yasuko; Hisatsune, Kunihiro

2011-01-01

The corrosion resistance of nine experimental Pd-free Ag-Au-Pt-Cu dental alloys in a 0.9% NaCl solution was investigated using cyclic voltammetry (CV), optical microscopy, and scanning electron microscopy (SEM). CV measurements revealed that the breakdown potential (E(bd)) and zero current potential (E(zc)) increased with increasing Au/(Au+Ag) atomic ratio. Thus, the Au/(Au+Ag) atomic ratio, but not the Cu content, influenced the corrosion resistance of Ag-Au-Pt-Cu alloys. After the forward scan of CV, both optical and scanning electron microscope images showed that in all the experimental alloys, the matrix phase was corroded but not the second phase. From corrosion resistance viewpoint, the Ag-Au-Pt-Cu alloys seemed to be suitable for clinical application.

Pressures of skarn formation at Casting Copper NV, USA, based on Raman spectroscopy and elastic modeling of apatite inclusions in garnet

NASA Astrophysics Data System (ADS)

Steele-MacInnis, M.; Barkoff, D. W.; Ashley, K.

2017-12-01

Thermobarometry of metasomatic rocks is commonly challenging, owing to the high variance of hydrothermal mineral assemblages, thermodynamic disequilibrium and overprinting by subsequent hydrothermal episodes. Here, we estimate formation pressures of a Cu-Fe-sulfide-bearing andradite-diopside skarn deposit at Casting Copper (Yerington district, NV) using Raman spectroscopy and elastic modeling of apatite inclusions in garnet. Andradite garnet from the Casting Copper skarn contains inclusions of hydroxyl-fluorapatite, calcite, hematite, magnetite, and ilmenite. Raman spectroscopy reveals that the apatite inclusions are predominantly under tension of -23 to -123 MPa at ambient conditions. Elastic modeling of apatite-in-garnet suggest entrapment occurred at 10 to 115 MPa, assuming a trapping temperature of 400 °C, which is consistent with paleodepth estimates of 2-3 km. These results provide independent constraints on the conditions of hydrothermal skarn formation at Casting Copper, and suggest that this approach may be applied to other, less-constrained skarn systems.

Au38Cu1(2-PET)24 nanocluster: synthesis, enantioseparation and luminescence.

PubMed

Kazan, Rania; Zhang, Bei; Bürgi, Thomas

2017-06-20

A CuAu 38 bimetallic nanocluster was synthesized by adding a single copper atom to the Au 38 (2-PET) 24 nanocluster. The absence of Cu x Au 38-x (2-PET) 24 doped species was demonstrated by MALDI-TOF mass spectrometry. A separation of bimetallic clusters was attained for the first time where isomers of the E2 enantiomer of the Au 38 Cu 1 (2-PET) 24 adduct were successfully isolated from their parent cluster using chiral HPLC. The CD of the isolated isomers revealed a change in their electronic structure upon copper addition. The luminescence of the Au 38 Cu 1 adduct is significantly enhanced in comparison with the parent Au 38 nanocluster. The stability of the newly formed adduct is strongly dependent on the coexistence of the Au 38 nanoclusters.

Geochronology and trace element geochemistry of titanite in the Machangqing Cu-Mo-dominated polymetallic deposit, Yunnan Province, southwest China

NASA Astrophysics Data System (ADS)

Fu, Yu; Sun, Xiaoming; Hollings, Pete; Li, Dengfeng; Yang, Tianjian

2018-06-01

The Machangqing Cu-Mo-dominated polymetallic deposit is a porphyry-skarn-epithermal Cu-Mo (-Au) metallogenic system located in the middle part of the Jinshajiang-Ailaoshan alkaline porphyry metallogenic belt. The skarn mineralization of the Machangqing deposit mainly occurs along the contacts between the alkalic porphyry intrusions and the surrounding Lower Ordovician Xiangyang Formation rocks. We present LA-ICP-MS U-Pb ages and trace element data for titanite from the Machangqing deposit in order to investigate the origin of this deposit. Based on mineral textures and assemblages, two types of titanite are recognized in Machangqing: magmatic titanite (Type I) from the granite porphyry and hydrothermal titanite from the mineralized skarn. The coarse-grained magmatic titanite is euhedral and occurs as discrete grains in the interstices of feldspar, quartz and biotite, whereas fine- to medium-grained hydrothermal titanite crystals (Type II) are euhedral to subhedral and occur in association with skarn minerals such as garnet, pyroxene and magnetite. Magmatic titanite has lower FeO, Al2O3, F and Nb/Ta but higher TiO2, Th/U, HFSEs and Lu/Hf than hydrothermal titanite. The magmatic titanite has higher LREE/HREE ratios and total REE contents with stronger negative Eu anomalies than its mineralized skarn counterpart. Trace elemental characteristics of hydrothermal titanite in Machangqing are consistent with relatively low F contents and oxygen fugacities when compared to the neighboring Beiya gold-dominated polymetallic deposit in the same metallogenic belt. The weighted average 206Pb/238U age of 34.3 ± 1.2 Ma of hydrothermal titanite is within error but slightly younger than the age of magmatic titanite (37.5 ± 4.1 Ma), indicating that the skarn mineralization followed the emplacement of the granite porphyry and was broadly coeval with the porphyry mineralization. The porphyry and skarn types of mineralization at Machangqing were formed from the same metallogenic

Geology, mineralization, and fluid inclusion characteristics of the Skrytoe reduced-type W skarn and stockwork deposit, Sikhote-Alin, Russia

NASA Astrophysics Data System (ADS)

Soloviev, Serguei G.; Kryazhev, Sergey G.

2017-08-01

The Skrytoe deposit (>145 Kt WO3, average grade 0.449% WO3) in the Sikhote-Alin orogenic system (Eastern Russia) is situated in a metallogenic belt of W, Sn-W, Au, and Au-W deposits formed in a late to post-collisional tectonic environment after cessation of active subduction. It is localized within a mineralized district of reduced-type skarn W and veined Au (±W) deposits and occurrences related to the Early Cretaceous ilmenite-series plutonic suite. The deposit incorporates large stockworks of scheelite-bearing veinlets related to propylitic (amphibole, chlorite, quartz) and phyllic (quartz, sericite, albite, apatite, and carbonate) hydrothermal alteration. The stockwork cuts flat-lying mafic volcanic rocks and limestone partially replaced by pyroxene skarn that host the major W orebodies. Scheelite is associated with pyrrhotite and/or arsenopyrite, with minor chalcopyrite and other sulfide minerals; the late phyllic stage assemblages hosts Bi and Au mineralization. The fluid evolution included low-salinity moderate-temperature, moderate-pressure (˜370-390 °C, ˜800 bars) methane-dominated carbonic-aqueous fluids that formed post-skarn propylitic alteration assemblages. Then, at the phyllic stage, there has been an evolution from methane-dominated, moderate-temperature (330-360 °C), low-salinity (<12.3 wt% NaCl equiv.) fluids forming the early quartz-sericite-albite-arsenopyrite assemblage, through lower temperature (290-330 °C) methane-dominated, low-salinity (˜9-10 wt% NaCl equiv.) fluids forming the intermediate quartz-sericite-albite-scheelite-pyrrhotite assemblage, to yet lower temperature (245-320 °C) CO2-dominated carbonic-aqueous low-salinity (˜1-7 wt% NaCl equiv.) fluids forming the late quartz-sericite-sulfide-Bi-Au assemblage. Recurrent fluid immiscibility (phase separation) and cooling probably affected W solubility and promoted scheelite deposition. The stable isotope data support a sedimentary source of carbon (δ13Cfluid = ˜-21 to -10 �

Comparative Reliability Studies and Analysis of Au, Pd-Coated Cu and Pd-Doped Cu Wire in Microelectronics Packaging

PubMed Central

Chong Leong, Gan; Uda, Hashim

2013-01-01

This paper compares and discusses the wearout reliability and analysis of Gold (Au), Palladium (Pd) coated Cu and Pd-doped Cu wires used in fineline Ball Grid Array (BGA) package. Intermetallic compound (IMC) thickness measurement has been carried out to estimate the coefficient of diffusion (Do) under various aging conditions of different bonding wires. Wire pull and ball bond shear strengths have been analyzed and we found smaller variation in Pd-doped Cu wire compared to Au and Pd-doped Cu wire. Au bonds were identified to have faster IMC formation, compared to slower IMC growth of Cu. The obtained weibull slope, β of three bonding wires are greater than 1.0 and belong to wearout reliability data point. Pd-doped Cu wire exhibits larger time-to-failure and cycles-to-failure in both wearout reliability tests in Highly Accelerated Temperature and Humidity (HAST) and Temperature Cycling (TC) tests. This proves Pd-doped Cu wire has a greater potential and higher reliability margin compared to Au and Pd-coated Cu wires. PMID:24244344

Cu-Au Alloys Using Monte Carlo Simulations and the BFS Method for Alloys

NASA Technical Reports Server (NTRS)

Bozzolo, Guillermo; Good, Brian; Ferrante, John

1996-01-01

Semi empirical methods have shown considerable promise in aiding in the calculation of many properties of materials. Materials used in engineering applications have defects that occur for various reasons including processing. In this work we present the first application of the BFS method for alloys to describe some aspects of microstructure due to processing for the Cu-Au system (Cu-Au, CuAu3, and Cu3Au). We use finite temperature Monte Carlo calculations, in order to show the influence of 'heat treatment' in the low-temperature phase of the alloy. Although relatively simple, it has enough features that could be used as a first test of the reliability of the technique. The main questions to be answered in this work relate to the existence of low temperature ordered structures for specific concentrations, for example, the ability to distinguish between rather similar phases for equiatomic alloys (CuAu I and CuAu II, the latter characterized by an antiphase boundary separating two identical phases).

Structural properties and diffusion processes of the Cu 3Au (0 0 1) surface

NASA Astrophysics Data System (ADS)

Wang, Fang; Zhang, Jian-Min; Zhang, Yan; Ji, Vincent

2010-09-01

The surface relaxation and surface energy of both the mixed AuCu and pure Cu terminated Cu 3Au (0 0 1) surfaces are simulated and calculated by using the modified analytical embedded-atom method. We find that the mixed AuCu termination is energetically preferred over the pure Cu termination thereby the mono-vacancy diffusion is also investigated in the topmost few layers of the mixed AuCu terminated Cu 3Au (0 0 1) surface. In the mixed AuCu terminated surface the relaxed Au atoms are raised above Cu atoms for 0.13 Å in the topmost layer. All the surface atoms displace outwards, this effect occurs in the first three layers and changes the first two inter-layer spacing. For mono-vacancy migration in the first layer, the migration energies of Au and Cu mono-vacancy via two-type in-plane displace: the nearest neighbor jump (NNJ) and the second nearest neighbor jump (2NNJ), are calculated and the results show that the NNJ requires a much lower energy than 2NNJ. For the evolution of the energy requirements for successive nearest neighbor jumps (SNNJ) along three different paths: circularity, zigzag and beeline, we find that the circularity path is preferred over the other two paths due to its minimum energy barriers and final energies. In the second layer, the NN jumps in intra- and inter-layer of the Cu mono-vacancy are investigated. The calculated energy barriers and final energies show that the vacancy prefer jump up to a proximate Cu site. This replacement between the Cu vacancy in the second layer and Cu atom in the first layer is remunerative for the Au atoms enrichment in the topmost layer.

An exploration hydrogeochemical study at the giant Pebble porphyry Cu-Au-Mo deposit, Alaska, USA, using high-resolution ICP-MS

USGS Publications Warehouse

Eppinger, Robert G.; Fey, David L.; Giles, Stuart A.; Kelley, Karen D.; Smith, Steven M.

2012-01-01

A hydrogeochemical study using high resolution ICP-MS was undertaken at the giant Pebble porphyry Cu-Au-Mo deposit and surrounding mineral occurrences. Surface water and groundwater samples from regional background and the deposit area were collected at 168 sites. Rigorous quality control reveals impressive results at low nanogram per litre (ng/l) levels. Sites with pH values below 5.1 are from ponds in the Pebble West area, where sulphide-bearing rubble crop is thinly covered. Relative to other study area waters, anomalous concentrations of Cu, Cd, K, Ni, Re, the REE, Tl, SO42− and F− are present in water samples from Pebble West. Samples from circum-neutral waters at Pebble East and parts of Pebble West, where cover is much thicker, have anomalous concentrations of Ag, As, In, Mn, Mo, Sb, Th, U, V, and W. Low-level anomalous concentrations for most of these elements were also found in waters surrounding nearby porphyry and skarn mineral occurrences. Many of these elements are present in low ng/l concentration ranges and would not have been detected using traditional quadrupole ICP-MS. Hydrogeochemical exploration paired with high resolution ICP-MS is a powerful new tool in the search for concealed deposits.

CHARGED PARTICLE MULTIPLICITIES IN ULTRA-RELATIVISTIC AU+AU AND CU+CU COLLISIONS

NASA Astrophysics Data System (ADS)

Back, B. B.; Alver, B.; 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.; Chetluru, V.; Decowski, M. P.; Garcia, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Halliwell, C.; Hamblen, J.; Harnarine, I.; Hauer, M.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Khan, N.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; Manly, S.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Reed, C.; Richardson, E.; Roland, C.; Roland, G.; Sagerer, J.; Seals, H.; Sedykh, I.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Szostak, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; Vannieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Willhelm, D.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wyngaardt, S.; Wyslouch, B.

The PHOBOS collaboration has carried out a systematic study of charged particle multiplicities in Cu+Cu and Au+Au collisions at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory. A unique feature of the PHOBOS detector is its ability to measure charged particles over a very wide angular range from 0.5° to 179.5° corresponding to |η| <5.4. The general features of the charged particle multiplicity distributions as a function of pseudo-rapidity, collision energy and centrality, as well as system size, are discussed.

Laser ablation of Au-CuO core-shell nanocomposite in water for optoelectronic devices

NASA Astrophysics Data System (ADS)

Ismail, Raid A.; Abdul-Hamed, Ryam S.

2017-12-01

Core-shell gold-copper oxide Au-CuO nanocomposites were synthesized using laser ablation of CuO target in colloidal solution of Au nanoparticles (NPs). The effect of laser fluence on the structural, morphological, electrical, and optical properties of Au-CuO nanocomposites was investigated using x-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM), photoluminescence (PL), Fourier transformed infrared spectroscopy (FTIR), Hall measurement, and UV-vis spectroscopy. X-ray diffraction results confirm the formation of polycrystalline Au-CuO NPs with monoclinic structure. The optical energy gap for CuO was 4 eV and for the Au-CuO core-shell nanocomposites was found to be in the range of 3.4-3.7 eV. SEM and TEM investigations revealed that the structure and morphology of Au-CuO core-shell nanocomposites were strongly depending on the laser fluence. A formation of Au-CuO nanospheres and platelets structures was observed. The photoluminescence data showed an emission of broad visible peaks between 407 and 420 nm. The effect of laser fluence on the dark and illuminated I-V characteristics of Au-CuO/n-Si heterojunction photodetectors was investigated and analyzed. The experimental data demonstrated that the photodetector prepared at optimum laser fluence exhibited photosensitivity of 0.6 AW-1 at 800 nm.

Trace Elements and Oxygen Isotope Zoning of the Sidewinder Skarn

NASA Astrophysics Data System (ADS)

Draper, C.; Gevedon, M. L.; Barnes, J.; Lackey, J. S.; Jiang, H.; Lee, C. T.

2016-12-01

Skarns of the Verde Antique Quarry and White Horse Mountain areas of the Sidewinder Range give insight into the paleohydrothermal systems operating in the California's Jurassic arc in the Southwestern Mojave Desert. Garnet from these skarns is iron rich: Xand= 55-100. Laser fluorination measurements show oxygen isotope (δ18O) compositions of garnet crystals and crystals domains have large ranges: -3.1‰ to +4.4‰ and -8.9‰ to +3.4‰, respectively. In general, the garnet cores have more negative δ18O values than rims, although oscillations are present. Negative values have been interpreted as influx of meteoric fluid and positive values as increased magmatic input. Here we report major and trace element concentrations for 17 core to rim Sidewinder garnet transects. REEs concentrations are low in all crystals, with total REE concentrations ranging from 0.710 ppm to 33.7 ppm, values that are lower than Cretaceous skarn garnets in the Sierra Nevada in the White Chief and Empire Mt skarns. Such low concentrations are likely due to the higher fraction of meteoric fluids during formation of the Sidewinder skarns. REE concentrations decrease from core to rim (REE core average=12.2ppm, REE rim average=7.21ppm). This is slightly more pronounced in the LREEs than in the HREEs (LaN/YbN core average= 10.9; rim average= 9.73, normalized to Chondrite). X­and tends to decrease core to rim in the Verde Antique skarn, whereas, Xand of the White Horse skarn does not correlate with distance from core. A large positive Eu anomaly (Eu/Eu* = 3­-30) in garnet from both skarns suggests oxidizing fluid conditions. Oxygen isotope data from garnet in these same skarns show periods of time with increased proportion of magmatic derived fluids in the total fluid budget. However, there is no corresponding widespread increase in total REE concentrations. Other studies of skarns from the western Sierra Nevadan arc (White Chief and Empire Mountain) observe complete decoupling of d18O values

Electrophoretic deposition of fluorescent Cu and Au sheets for light-emitting diodes

NASA Astrophysics Data System (ADS)

Liu, Jiale; Wu, Zhennan; Li, Tingting; Zhou, Ding; Zhang, Kai; Sheng, Yu; Cui, Jianli; Zhang, Hao; Yang, Bai

2015-12-01

Electrophoretic deposition (EPD) is a conventional method for fabricating film materials from nanometer-sized building blocks, and exhibits the advantages of low-cost, high-efficiency, wide-range thickness adjustment, and uniform deposition. Inspired by the interest in the application of two-dimensional (2D) nanomaterials, the EPD technique has been recently extended to building blocks with 2D features. However, the studies are mainly focused on simplex building blocks. The utilization of multiplex building blocks is rarely reported. In this work, we demonstrate a controlled EPD of Cu and Au sheets, which are 2D assemblies of luminescent Cu and Au nanoclusters. Systematic investigations reveal that both the deposition efficiency and the thickness are determined by the lateral size of the sheets. For Cu sheets with a large lateral size, a high ζ-potential and strong face-to-face van der Waals interactions facilitate the deposition with high efficiency. However, for Au sheets, the small lateral size and ζ-potential limit the formation of a thick film. To solve this problem, the deposition dynamics are controlled by increasing the concentration of the Au sheets and adding acetone. This understanding permits the fabrication of a binary EPD film by the stepwise deposition of Cu and Au sheets, thus producing a luminescent film with both Cu green emission and Au red emission. A white light-emitting diode prototype with color coordinates (x, y) = (0.31, 0.36) is fabricated by employing the EPD film as a color conversion layer on a 365 nm GaN clip and further tuning the amount of deposited Cu and Au sheets.Electrophoretic deposition (EPD) is a conventional method for fabricating film materials from nanometer-sized building blocks, and exhibits the advantages of low-cost, high-efficiency, wide-range thickness adjustment, and uniform deposition. Inspired by the interest in the application of two-dimensional (2D) nanomaterials, the EPD technique has been recently extended to

Study of submonolayer films of Au/Cu(100) and Pd/Cu(100) using positron annihilation induced auger electron spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, K.D.

1992-01-01

Positron Annihilation induced Auger Electron Spectroscopy (PAES), electron induced Auger Electron Spectroscopy (EAES), and Low Energy Electron Diffraction (LEED) have been used to study the surface composition, surface alloying and overlayer formation of ultrathin films of Au and Pd on Cu(100). This is the first systematic application of PAES to the study of the surface properties of ultrathin layers of metals on metal substrates. Temperature induced changes in the top layer surface compositions in Au/Cu(100) and Pd/Cu(100) are directly observed using PAES, while EAES spectra indicate only minor changes. The surface alloying of the Au/Cu(100) and Pd/Cu(100) systems are demonstratedmore » using PAES in conjunction with LEED. The PAES intensity measurements also provide evidence for positron trapping at surface defects such as steps, kinks and isolated adatoms. The PAES intensity was found to be strongly dependent on surface effects introduced by ion sputtering. The surface defect dependence of the PAES intensity is interpreted in terms of the surface atomic diffusion and positron trapping at surface defects in Au/Cu(100) and Pd/Cu(100). In both systems the shapes of the PAES intensity versus coverage curves for submonolayer coverages at 173K are quite distinct indicating differences in overlayer growth and diffusion behavior of Au and Pd adatoms on the Cu(100) surface. PAES intensities for both Au and Pd are saturated at 1 monolayer demonstrating the extreme surface selectivity of PAES.« less

Photoelectron spectroscopic and computational study of (M-CO2)- anions, M = Cu, Ag, Au

NASA Astrophysics Data System (ADS)

Zhang, Xinxing; Lim, Eunhak; Kim, Seong K.; Bowen, Kit H.

2015-11-01

In a combined photoelectron spectroscopic and computational study of (M-CO2)-, M = Au, Ag, Cu, anionic complexes, we show that (Au-CO2)- forms both the chemisorbed and physisorbed isomers, AuCO 2- and Au-(CO2), respectively; that (Ag-CO2)- forms only the physisorbed isomer, Ag-(CO2); and that (Cu-CO2)- forms only the chemisorbed isomer, CuCO 2- . The two chemisorbed complexes, AuCO 2- and CuCO 2- , are covalently bound, formate-like anions, in which their CO2 moieties are significantly reduced. These two species are examples of electron-induced CO2 activation. The two physisorbed complexes, Au-(CO2) and Ag-(CO2), are electrostatically and thus weakly bound.

Galvanic corrosion behaviors of Cu connected to Au on a printed circuit board in ammonia solution

NASA Astrophysics Data System (ADS)

Oh, SeKwon; Kim, YoungJun; Jung, KiMin; Park, MiSeok; Shon, MinYoung; Kwon, HyukSang

2018-01-01

During etching treatments of printed circuit board (PCB) with ammnioa solution, galvanic corrosion occurs between electrically connected gold and copper, and resulting in unexpected over-etching problems. Herein, we determine corrosion of galvanic coupled Cu to Au quantitatively in ammonia solutions, and evaluate factors influencing corrosion of galvanic coupled Cu to Au (i.e., area ratio of anode to cathode and stirring speed). The difference of the corrosion rate (Δi = icouple, (Cu-Au)-icorr, Cu) of Cu connected to Au (117 μA/cm2) and of single Cu (86 μA/cm2) infers the amount of over-etching of Cu resulting from galvanic corrosion in ammonia solution (Δi = 0.31 μA/cm2). As the stirring speed increases from 0 to 400 rpm, the corrosion rate of galvanic coupled Cu to Au increases from 36 to 191 μA/cm2. Furthermore, we confirm that an increase in the area ratio (Au/Cu) from 0.5 to 25 results in a higher rate of corrosion of Cu connected to Au. The corrosion rate of galvanic coupled Cu to Au is approximately 20 times higher when the area ratio of Au to Cu is 25 (1360 μA/cm2) than when the ratio is 0.5 (67 μA/cm2).

Mineralogy, geochemistry, and evolution of the Mivehrood skarn and the associated pluton, northwest Iran

NASA Astrophysics Data System (ADS)

Alirezaei, Saeed; Einali, Morteza; Jones, Peter; Hassanpour, Shohreh; Arjmandzadeh, Reza

2016-04-01

An Upper Miocene (9.12 ± 0.19 Ma; biotite 40Ar/39Ar) shallow pluton and numerous dykes and sills of felsic-intermediate compositions intruded the Upper Cretaceous, flysch-type sediments in the Mivehrood area, northwest Iran. The intrusions caused extensive thermal metamorphism and metasomatism, leading to the formation of hornfels and skarn. A massive skarn, 1-10 m thick, immediate to the intrusive contact, is bordered by a banded skarn, 100-400 m thick, that grades outward into hornfels and original sediments. The Mivehrood pluton is characterized by steep REE pattern, high Al2O3 (14.64-16.4 wt%) and Sr (380-786 ppm), and low MgO (1.3-3.4 wt%), Y (4.8-10.7 ppm), and Yb (0.35-0.95 ppm), characteristics typical of high-silica adakites. Skarn formation started with thermal metamorphism, followed by anhydrous prograde and hydrous retrograde stages. Prograde and retrograde mineral assemblages are developed in both skarns, represented by garnet-clinopyroxene-wollastonite and epidote-actinolite-scapolite-chlorite, respectively. Granditic F-bearing garnet dominates clinopyroxene in both skarns. The banded skarn contains minor scapolite of marialite composition. The calc-silicate mineral assemblages and the mineral chemistry allow the Mivehrood skarn to be classified as a calcic, oxidized skarn. Mass balance assessments suggest that Fe, Si, and S were significantly enriched, and Na, LILEs, and LREEs were strongly depleted, in the massive skarn. In the banded skarn, Na, K, Si, and S were enriched. Significant dehydration and carbon degassing occurred in both skarns. Stockworks, veins, and replacement bodies of pyrite ± chalcopyrite locally occur in the pluton and the dykes and in the skarns. The δ34SCDT values for the sulfides fall in a narrow range around 0.0 ‰, suggesting a magmatic source for sulfur and possibly the hydrothermal water and solutes involved in the skarn formation.

Geology, mineralization, and fluid inclusion characteristics of the Kashkasu W-Mo-Cu skarn deposit associated with a high-potassic to shoshonitic igneous suite in Kyrgyzstan, Tien Shan: Toward a diversity of W mineralization in Central Asia

NASA Astrophysics Data System (ADS)

Soloviev, Serguei G.; Kryazhev, Sergey G.

2018-03-01

The Kashkasu deposit is part of the subduction-related Late Paleozoic (Late Carboniferous) metallogenic belt of Tien Shan. It is associated with a multiphase monzodiorite-monzonite-granodiorite-granite pluton of the magnetite-series high-K calc-alkaline to shoshonitic igneous suite. The deposit contains zones of W-Mo-Cu oxidized prograde and retrograde skarns, with abundant andraditic garnet, magnetite, locally scapolite and K-feldspar, as well as scheelite, chalcopyrite, and molybdenite. Skarns are overprinted by quartz-carbonate-sericite (phyllic alteration) zones with scheelite and sulfides. Prograde calcic skarn and initial retrograde skarns were formed from a high temperature (650 °C to 450-550 °C), high pressure (2000 bars to 600-900 bars) magmatic-hydrothermal low- to high-salinity aqueous chloride fluid. The gradual fluid evolution was interrupted by the intrusion of granodiorite and likely associated release of low-salinity (∼7-8 wt% NaCl equiv.) fluid. Ascent of this fluid to shallower levels and/or its cooling to 400-500 °C has resulted in phase separation into low-salinity (2.1-3.1 wt% NaCl equiv.) vapor and coexisting brine (35-40 wt% NaCl equiv.). The boiling was coincident with most intense scheelite deposition in retrograde skarn. Later retrograde skarn assemblages were formed from a gaseous, low- to moderate-salinity (3.4-8.1 wt% NaCl equiv.) fluid and then from high salinity (37-42 wt% NaCl equiv.) aqueous chloride fluids, the latter being enriched in Ca (17-20 wt% CaCl2) that could also affect scheelite deposition. Another cycle of fluid exsolution from crystallizing magma corresponded to quartz-carbonate-sericite-scheelite-sulfide (phyllic) alteration stage, with the early low-salinity (5.3-8.4 wt% NaCl-equiv.) fluid followed by later high-salinity (33.5-38.2 wt% NaCl-equiv.) fluid. The sulfur isotope data (δ34S = +5.1 to +9.0) suggest significant sulfur sourcing from sedimentary rocks enriched in seawater sulfate, possibly evaporites.

Inelastic X-ray scattering of RTAl3 (R = La, Ce, T = Cu, Au)

NASA Astrophysics Data System (ADS)

Tsutsui, Satoshi; Kaneko, Koji; Pospisil, Jiri; Haga, Yoshinori

2018-05-01

Inelastic X-ray scattering (IXS) experiments of RTAl3 (R = La Ce, T = Cu, Au) were carried out at 300 and 5.5 K. The spectra between LaCuAl3 and CeCuAl3 (LaAuAl3 and CeAuAl3) are nearly identical at both temperatures except for temperature factors such as temperature dependence of Bose factor in IXS spectra and effect on thermal expansion. This means that no evident temperature dependence of IXS spectra was observed in CeTAl3 (T = Cu, Au). Since the major contribution of scattering cross section in IXS measurements is Thomson scattering, the present results failed to confirm the presence of vibron in these compounds.

Study of Sn and SnAgCu Solders Wetting Reaction on Ni/Pd/Au Substrates

NASA Astrophysics Data System (ADS)

Liu, C. Y.; Wei, Y. S.; Lin, E. J.; Hsu, Y. C.; Tang, Y. K.

2016-12-01

Wetting reactions of pure Sn and Sn-Ag-Cu solder balls on Au(100 Å and 1000 Å)/Pd(500 Å)/Ni substrates were investigated. The (Au, Pd)Sn4 phase formed in the initial interfacial reaction between pure Sn and Au(100 Å and 1000 Å)/Pd(500 Å)/Ni substrates. Then, the initially formed (Au, Pd)Sn4 compound layer either dissolved or spalled into the molten Sn solder with 3 s of reflowing. The exposed Ni under-layer reacted with Sn solder and formed an interfacial Ni3Sn4 compound. We did not observe spalling compound in the Sn-Ag-Cu case, either on the thin Au (100 Å) or the thick Au (1000 Å) substrates. This implies that the Cu content in the Sn-Ag-Cu solder can efficiently suppress the spalling effect and really stabilize the interfacial layer. Sn-Ag-Cu solder has a better wetting than that of the pure Sn solder, regardless of the Au thickness of the Au/Pd/Ni substrate. For both cases of pure Sn and Sn-Ag-Cu, the initial wetting (<3-s reflowing) on the thin Au (100 Å) substrate is better than that of the thick Au (1000 Å) substrate. Over 3-s reflowing, the wetting on the thicker Au layer (1000 Å) substrate becomes better than the wetting on the thinner Au layer (100 Å) substrate.

Au plasmonics in a WS{sub 2}-Au-CuInS{sub 2} photocatalyst for significantly enhanced hydrogen generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cheng, Zhongzhou; School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083; Wang, Zhenxing, E-mail: wangzx@nanoctr.cn, E-mail: hej@nanoctr.cn

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 optimizemore » the type-II structures for photocatalytic water splitting.« less

Porphyry Cu-Au mineralization in the Mirkuh Ali Mirza magmatic complex, NW Iran

NASA Astrophysics Data System (ADS)

Maghsoudi, A.; Yazdi, M.; Mehrpartou, M.; Vosoughi, M.; Younesi, S.

2014-01-01

The Mirkuh Ali Mirza Cu-Au porphyry system in East Azerbaijan Province is located on the western part of the Cenozoic Alborz-Azerbaijan volcanic belt. The belt is also an important Cu-Mo-Au metallogenic province in northwestern Iran. The exposed rocks in the study area consist of a volcaniclastic sequence, subvolcanic rocks and intermediate to mafic lava flows of Neogene age. The volcanic rocks show a typical subduction-related magmatic arc geological and geochemical signature, with low concentration of Nb, Ta, and Ti. Mineralization is hosted by Neogene dacitic tuff and porphyritic dacite situated at the intersections of northeast and northwest faults. Field observations, alteration zonation, geochemical haloes and isotopic data of the Mirkuh Ali Mirza magmatic complex show similarities with typical convergent margin Cu-Au porphyry type deposits. The following features confirm the classic model for Cu-Au porphyry systems: (a) close spatial association with high-K calcalkaline to shoshonitic rock related to post-collision extensional setting (b) low grade Cu (0.57%) (c) stockworks as well as disseminated sulfides (c) zonality of the alteration patterns from intense phyllic at the center to outward weak-phyllic, argillic, and propylitic (d) the presence of a pyritic halo (e) accompanied by sheeted veins and low-sulfidation epithermal gold (f) mineralization spatially associated with intersection of structures, (g) genetically related to diorite porphyry stocks at depth (h) geochemical zonation of (Cu ± Au ± Ag ± Bi) → (Cu + Mo ± Bi ± Au ± Pb ± Zn ± As) → (Au + Mo ± Pb ± Zn) → (As + Ag + Sb + Mn + Ba + Pb + Zn + Hg) → Hg from center to outwards (i) The range of sulfur isotopic values is approximately zero (interpreted to have magmatic source) and similar to other subduction-related porphyry Cu deposits.

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.

Nanoscale electrical characteristics of metal (Au, Pd)-graphene-metal (Cu) contacts

NASA Astrophysics Data System (ADS)

Ruffino, F.; Meli, G.; Grimaldi, M. G.

2016-01-01

Free-standing graphene presents exceptional physical properties (as a high carrier mobility) making it the ideal candidate for the next generation nanoelectronics. However, when graphene layers are inserted in real electronics devices, metal contacting is required. The metal-graphene interaction significantly affects the graphene electrical properties, drastically changing its behavior with respect to the free-standing configuration. So, this work presents an experimental study on the nanoscale electric characteristics of metal/graphene/metal contacts. In particular, starting from single-layer graphene grown on Cu foil we deposited on the graphene surface two different metal films (Au or Pd) and the Au/graphene/Cu and Pd/graphene/Cu current-voltage characteristics are acquired, on the nanometric scale, by the conductive atomic force microscopy. Both systems presented a current voltage rectifying behavior. However, the Au/graphene/Cu system conducts significantly at negative applied bias (graphene behaves as a p-type semiconductor in a meta/semiconductor contact), while in the Pd/graphene/Cu at positive applied bias (graphene behaves as a n-type semiconductor in a metal/semiconductor contact). This difference is discussed on the basis of the band energy diagram at the metal/graphene interface and the modification of the graphene Fermi level due to the Au/graphene or Pd/graphene interaction.

Cu2O-directed in situ growth of Au nanoparticles inside HKUST-1 nanocages.

PubMed

Liu, Yongxin; Liu, Ting; Tian, Long; Zhang, Linlin; Yao, Lili; Tan, Taixing; Xu, Jin; Han, Xiaohui; Liu, Dan; Wang, Cheng

2016-12-07

Controllable integration of metal nanoparticles (MNPs) and metal-organic frameworks (MOFs) is attracting considerable attention as the obtained composite materials always show synergistic effects in applications of catalysis, delivery, as well as sensing. Herein, a Cu 2 O-directed in situ growth strategy was developed to integrate Au nanoparticles and HKUST-1. In this strategy, Cu 2 O@HKUST-1 core-shell heterostructures, HKUST-1 nanocages, Cu 2 O@Au@HKUST-1 sandwich core-shell heterostructures and Au@HKUST-1 balls-in-cage heterostructures were successfully synthesized. Cu 2 O@HKUST-1 core-shell heterostructures were synthesized by soaking Cu 2 O nanocrystals in benzene-1,3,5-tricarboxylic acid solution. The well-defined Cu 2 O@HKUST-1 core-shell heterostructures were demonstrated to be dominated by the ratio of Cu 2+ cations to btc 3- ligands in solution during the period of HKUST-1 formation. Cu 2 O@Au@HKUST-1 sandwich core-shell or Au@HKUST-1 balls-in-cage heterostructures were obtained by impregnating HAuCl 4 into Cu 2 O@HKUST-1 core-shell heterostructures. Due to the porosity of HKUST-1 and reducibility of Cu 2 O, HAuCl 4 could pass through the HKUST-1 shell and be reduced by the Cu 2 O core in situ forming Au nanoparticles. Finally, CO oxidation reaction at high temperatures was carried out to assess the catalytic functionality of the obtained composite heterostructures. This strategy can circumvent some drawbacks of the existing approaches for integrating MNPs and MOFs, such as nonselective deposition of MNPs at the outer surface of the MOF matrices, extreme treatment conditions and additional surface modifications.

On the nature of L1{sub 0} ordering in equiatomic AuNi and AuCu thin films grown on Au(001)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dynna, M.; Marty, A.; Gilles, B.

1997-01-01

The L1{sub 0} ordering of thin epitaxial films having a (001) surface normal subject to elastic constraints imposed by a similarly oriented substrate has been investigated both experimentally and theoretically. Thin AuNi films grown by MBE at room temperature on Au(001) by means of the alternating deposition of Au and Ni are found to possess a L1{sub 0} structure free of periodic antiphase boundaries when growth is controlled in such a way as to ensure that the quantity of Au or Ni deposited is almost exactly equal to one monolayer. If such control is not exercised during growth, a structuremore » having periodic antiphase boundaries is formed. This behavior stands in contrast to that of AuCu during room temperature MBE growth on Au(001), where a strongly ordered L2{sub 0} structure free of antiphase boundaries is formed even on the codeposition of Au and Cu. The effect of elastic constraints on the state of order in an alloy film which undergoes an L2{sub 0} order-disorder transition is examined as a function of temperature, lattice mismatch, and film thickness within the context of a model which allows for the introduction of dislocations in order to relieve misfit strain. Calculations are performed in detail for the case of AuCu, where particular attention is paid to the coupling between film thickness, the number of misfit dislocations present at equilibrium, and the state of order.« less

Covellite CuS as a matrix for "invisible" gold: X-ray spectroscopic study of the chemical state of Cu and Au in synthetic minerals

NASA Astrophysics Data System (ADS)

Tagirov, Boris R.; Trigub, Alexander L.; Kvashnina, Kristina O.; Shiryaev, Andrey A.; Chareev, Dmitriy A.; Nickolsky, Maximilian S.; Abramova, Vera D.; Kovalchuk, Elena V.

2016-10-01

Geological processes leading to formation of sulfide ores often result in precipitation of gold-bearing sulfides which can contain high concentrations of this metal in ;invisible; (or ;refractory;) state. Covellite (CuS) is ubiquitous mineral in many types of the ore deposits, and numerous studies of the natural ores show that covellite can contain high concentrations of Au. At the same time, Au-bearing covellite withstands cooling in contrast to other minerals of the Cu-Fe-S system (chalcocite, bornite, chalcopyrite), where Au exsolves at low temperatures. This makes covellite a convenient model system for investigation of the chemical state (local environment and valence) of the ;invisible; Au in copper-sulfide ores (copper-porphyry, epithermal, volcanogenic massive sulfide, SEDEX deposits). Therefore, it is necessary to determine the location of Au in the covellite matrix as it will have important implications for the methods employed by mineral processing industry to extract Au from sulfide ores. Here we investigate the chemical state of Cu and Au in synthetic covellite containing up to 0.3 wt.% of Au in the ;invisible; state. The covellite crystals were synthesized by hydrothermal and salt flux methods. Formation of the chemically bound Au is indicated by strong dependence of the concentration of Au in covellite on the sulfur fugacity in the experimental system (d(log C(Au))/d(log f(S2)) ∼ 0.65). The Au concentration of covellite grows with increasing temperature from 400 to 450 °C, whereas further temperature increase to 500 °C has only minor effect. The synthesized minerals were studied using X-ray absorption fine structure spectroscopy (XAFS) in high energy resolution fluorescence detection (HERFD) mode. Ab initio simulations of Cu K edge XANES spectra show that the Cu oxidation state in two structural positions in covellite (tetrahedral and triangular coordination with S atoms) is identical: the total loss of electronic charge for the 3d shell is ∼0

Charged-particle multiplicity and pseudorapidity distributions measured with the PHOBOS detector in Au+Au, Cu+Cu, d+Au, and p+p collisions at ultrarelativistic energies

NASA Astrophysics Data System (ADS)

Alver, B.; 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.; Chetluru, V.; Decowski, M. P.; García, E.; Gburek, T.; 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.; Kotuła, J.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Li, W.; Lin, W. T.; Loizides, C.; 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.; Sedykh, I.; Skulski, W.; Smith, C. E.; Steadman, S. G.; Steinberg, P.; Stephans, G. S. F.; Stodulski, M.; Sukhanov, A.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Wadsworth, B.; Walters, P.; Wenger, E.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wysłouch, B.

2011-02-01

Pseudorapidity distributions of charged particles emitted in Au+Au, Cu+Cu, d+Au, and p+p collisions over a wide energy range have been measured using the PHOBOS detector at the BNL Relativistic Heavy-Ion Collider (RHIC). The centrality dependence of both the charged particle distributions and the multiplicity at midrapidity were measured. Pseudorapidity distributions of charged particles emitted with |η|<5.4, which account for between 95% and 99% of the total charged-particle emission associated with collision participants, are presented for different collision centralities. Both the midrapidity density dNch/dη and the total charged-particle multiplicity Nch are found to factorize into a product of independent functions of collision energy, sNN, and centrality given in terms of the number of nucleons participating in the collision, Npart. The total charged particle multiplicity, observed in these experiments and those at lower energies, assumes a linear dependence of (lnsNN)2 over the full range of collision energy of sNN=2.7-200 GeV.

Effects of temperature and operation parameters on the galvanic corrosion of Cu coupled to Au in organic solderability preservatives process

NASA Astrophysics Data System (ADS)

Oh, SeKwon; Kim, YoungJun; Jung, KiMin; Kim, JongSoo; Shon, MinYoung; Kwon, HyukSang

2017-03-01

In this work, we quantitatively examined the effects of temperature and operation parameters such as anode (Cu) to cathode (Au) area ratio, stirring speed, and Cu ion concentration on the galvanic corrosion kinetics of Cu coupled to Au (icouple ( Cu-Au)) on print circuit board in organic solderability preservative (OSP) soft etching solution. With the increase of temperature, galvanic corrosion rate (icouple ( Cu-Au) was increased; however, the degree of galvanic corrosion rate (icouple ( Cu-Au) - icorr (Cu)) was decreased owing to the lower activation energy of Cu coupled to Au, than that of Cu alone. With the increase of area ratio (cathode/anode), stirring speed of the system, icouple ( Cu-Au) was increased by the increase of cathodic reaction kinetics. And icouple ( Cu-Au) was decreased by the increase of the Cu-ion concentration in the OSP soft etching solution.

Microstructural and electrical properties of Al/n-type Si Schottky diodes with Au-CuPc nanocomposite films as interlayer

NASA Astrophysics Data System (ADS)

Reddy, P. R. Sekhar; Janardhanam, V.; Jyothi, I.; Chang, Han-Soo; Lee, Sung-Nam; Lee, Myung Sun; Reddy, V. Rajagopal; Choi, Chel-Jong

2017-11-01

Au-CuPc nanocomposite films were prepared by simultaneous evaporation of Au and CuPc with various Au and CuPc concentrations. Microstructural analysis of Au-CuPc films revealed elongated Au cluster formation from isolated Au nanoclusters with increasing Au concentration associated with coalescence of Au clusters. Au-CuPc films with different compositions were employed as interlayer in Al/n-Si Schottky diode. Barrier height and series resistance of the Al/n-Si Schottky diode with Au-CuPc interlayer decreased with increasing Au concentration. This could be associated with the enhancement of electron tunneling between neighboring clusters due to decrease in spacing of Au clusters and formation of conducting paths through the composite material. Interface state density of the Al/n-Si Schottky diode with Au-CuPc interlayer increased with increasing Au concentration. This might be because the inclusion of metal decreases the crystallinity and crystal size of the polymer matrix accompanied by the formation of local defect sites at the places of metal nucleation.

Fabrication of bimetallic Cu/Au nanotubes and their sensitive, selective, reproducible and reusable electrochemical sensing of glucose

NASA Astrophysics Data System (ADS)

Tee, Si Yin; Ye, Enyi; Pan, Pei Hua; Lee, Coryl Jing Jun; Hui, Hui Kim; Zhang, Shuang-Yuan; Koh, Leng Duei; Dong, Zhili; Han, Ming-Yong

2015-06-01

Herein, we report a facile two-step approach to produce gold-incorporated copper (Cu/Au) nanostructures through controlled disproportionation of the Cu+-oleylamine complex at 220 °C to form copper nanowires and the subsequent reaction with Au3+ at different temperatures of 140, 220 and 300 °C. In comparison with copper nanowires, these bimetallic Cu/Au nanostructures exhibit their synergistic effect to greatly enhance glucose oxidation. Among them, the shape-controlled Cu/Au nanotubes prepared at 140 °C show the highest electrocatalytic activity for non-enzymatic glucose sensing in alkaline solution. In addition to high sensitivity and fast response, the Cu/Au nanotubes possess high selectivity against interferences from other potential interfering species and excellent reproducibility with long-term stability. By introducing gold into copper nanostructures at a low level of 3, 1 and 0.1 mol% relative to the initial copper precursor, a significant electrocatalytic enhancement of the resulting bimetallic Cu/Au nanostructures starts to occur at 1 mol%. Overall, the present fabrication of stable Cu/Au nanostructures offers a promising low-cost platform for sensitive, selective, reproducible and reusable electrochemical sensing of glucose.Herein, we report a facile two-step approach to produce gold-incorporated copper (Cu/Au) nanostructures through controlled disproportionation of the Cu+-oleylamine complex at 220 °C to form copper nanowires and the subsequent reaction with Au3+ at different temperatures of 140, 220 and 300 °C. In comparison with copper nanowires, these bimetallic Cu/Au nanostructures exhibit their synergistic effect to greatly enhance glucose oxidation. Among them, the shape-controlled Cu/Au nanotubes prepared at 140 °C show the highest electrocatalytic activity for non-enzymatic glucose sensing in alkaline solution. In addition to high sensitivity and fast response, the Cu/Au nanotubes possess high selectivity against interferences from other

Wetting Behavior of Ternary Au-Ge-X (X = Sb, Sn) Alloys on Cu and Ni

NASA Astrophysics Data System (ADS)

Jin, S.; Valenza, F.; Novakovic, R.; Leinenbach, C.

2013-06-01

Au-Ge-based alloys are potential substitutes for Pb-rich solders currently used for high-temperature applications. In the present work, the wetting behavior of two Au-Ge-X (X = Sb, Sn) ternary alloys, i.e., Au-15Ge-17Sb and Au-13.7 Ge-15.3Sn (at.%), in contact with Cu and Ni substrates has been investigated. Au-13.7Ge-15.3Sn alloy showed complete wetting on both Cu and Ni substrates. Total spreading of Au-15Ge-17Sb alloy on Cu was also observed, while the final contact angle of this alloy on Ni was about 29°. Pronounced dissolution of Cu substrates into the solder alloys investigated was detected, while the formation of Ni-Ge intermetallic compounds at the interface of both solder/Ni systems suppressed the dissolution of Ni into the solder.

Fabrication and surface enhanced Raman scattering effect of centimeter level AgCuAu composite nanowires

NASA Astrophysics Data System (ADS)

Xu, Dapeng; Zhang, Song; Yang, Wei; Chen, Jian

2017-10-01

Centimeter level AgCuAu composite nanowires were prepared by a solid-state ionics method under a direct current electric field (DCEF) using fast ionic conductor RbAg4I5 films and vacuum thermal evaporation method. The surface morphology and chemical composition of the AuAgCu composite nanowires were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. Raman enhancement performance of the AgCuAu composite nanowires substrates was detected by Rhodamine 6G (R6G) aqueous solutions as probe molecules. Long-range order and short-range order AgCuAu composite nanowires with the length of 1 cm were prepared. The nanowires were bamboo-shaped with high surface roughness and the diameters of nanowires ranged from 60 to 100 nm. The molar ratio of Ag:Cu:Au in composite nanowires is 15:2:1. The intrinsic Raman peaks of 10-16 mol/L R6G at 612, 773, 1125, 1182, 1307, 1361, 1418, 1506, 1545, 1575, 1597, 1650 cm-1 are all present when AgCuAu composite nanowires were used as the SERS substrates.

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.

Pulse laser ablation of Au, Ag, and Cu metal targets in liquid for nanoparticle production

NASA Astrophysics Data System (ADS)

Herbani, Y.; Irmaniar; Nasution, R. S.; Mujtahid, F.; Masse, S.

2018-03-01

We have fabricated metal and oxide nanoparticles using pulse laser ablation of Au, Ag, and Cu metal targets immersed in water. While laser ablation of Au and Ag targets in water produced metal nanoparticles which were stable for a month even without any dispersant, we found CuO nanoparticles for Cu target due to rapid oxidation of Cu in water resulted in its poor stability. Au, Ag, and CuO nanoparticles production were barely identified by naked eyes for their distinctive colour of red, yellow, and dark green colloidal suspensions, respectively. It was also verified using UV-Vis spectrometer that Au, Ag, and CuO colloidal nanoparticles have their respective surface plasmon resonance at 520, 400, and 620 nm. TEM observation showed that particle sizes for all the fabricated nanoparticles were in the range of 20 – 40 nm with crystalline structures.

Large scale structural optimization of trimetallic Cu-Au-Pt clusters up to 147 atoms

NASA Astrophysics Data System (ADS)

Wu, Genhua; Sun, Yan; Wu, Xia; Chen, Run; Wang, Yan

2017-10-01

The stable structures of Cu-Au-Pt clusters up to 147 atoms are optimized by using an improved adaptive immune optimization algorithm (AIOA-IC method), in which several motifs, such as decahedron, icosahedron, face centered cubic, sixfold pancake, and Leary tetrahedron, are randomly selected as the inner cores of the starting structures. The structures of Cu8AunPt30-n (n = 1-29), Cu8AunPt47-n (n = 1-46), and partial 75-, 79-, 100-, and 147-atom clusters are analyzed. Cu12Au93Pt42 cluster has onion-like Mackay icosahedral motif. The segregation phenomena of Cu, Au and Pt in clusters are explained by the atomic radius, surface energy, and cohesive energy.

Au-Ag-Cu nano-alloys: tailoring of permittivity

NASA Astrophysics Data System (ADS)

Hashimoto, Yoshikazu; Seniutinas, Gediminas; Balčytis, Armandas; Juodkazis, Saulius; Nishijima, Yoshiaki

2016-04-01

Precious metal alloys enables new possibilities to tailor materials for specific optical functions. Here we present a systematic study of the effects of a nanoscale alloying on the permittivity of Au-Ag-Cu metals at 38 different atomic mixing ratios. The permittivity was measured and analyzed numerically by applying the Drude model. X-ray diffraction (XRD) revealed the face centered cubic lattice of the alloys. Both, optical spectra and XRD results point towards an equivalent composition-dependent electron scattering behavior. Correlation between the fundamental structural parameters of alloys and the resulting optical properties is elucidated. Plasmonic properties of the Au-Ag-Cu alloy nanoparticles were investigated by numerical simulations. Guidelines for designing plasmonic response of nano- structures and their patterns are presented from the material science perspective.

Construction of CuS/Au Heterostructure through a Simple Photoreduction Route for Enhanced Electrochemical Hydrogen Evolution and Photocatalysis

NASA Astrophysics Data System (ADS)

Basu, Mrinmoyee; Nazir, Roshan; Fageria, Pragati; Pande, Surojit

2016-10-01

An efficient Hydrogen evolution catalyst has been developed by decorating Au nanoparticle on the surface of CuS nanostructure following a green and environmental friendly approach. CuS nanostructure is synthesized through a simple wet-chemical route. CuS being a visible light photocatalyst is introduced to function as an efficient reducing agent. Photogenerated electron is used to reduce Au(III) on the surface of CuS to prepare CuS/Au heterostructure. The as-obtained heterostructure shows excellent performance in electrochemical H2 evolution reaction with promising durability in acidic condition, which could work as an efficient alternative for novel metals. The most efficient CuS-Au heterostructure can generate 10 mA/cm2 current density upon application of 0.179 V vs. RHE. CuS-Au heterostructure can also perform as an efficient photocatalyst for the degradation of organic pollutant. This dual nature of CuS and CuS/Au both in electrocatalysis and photocatalysis has been unveiled in this study.

Nanocrystallization of Zr-Cu-Ni-Al-Au glassy alloys during severe plastic deformation

NASA Astrophysics Data System (ADS)

Yamada, Masahiro; Kamisato, Ryo; Yamasaki, Tohru; Adachi, Hiroki; Tsuchiya, Koichi; Yokoyama, Yoshihiko

2014-08-01

A study has been carried out into the formation of nanocrystalline grains during high-pressure torsion (HPT) deformation of Zr65Cu17Ni5Al10Au3 bulk alloys prepared using tilt casting. As a preliminary to this, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analyses were carried out on as-cast Zr65+xCu17-xNi5Al10Au3 (x=0~5 at.%) and Zr65Cu20Ni5Al10Au3 alloys, in order to determine the effect on the microstructure of the excess Zr content x and the presence of Au. From the XRD patterns, it was determined that all of the alloys had a metallic glassy nature. For Zr65Cu17Ni5Al10Au3, the DSC results indicated the presence of a wide supercooled liquid region between the glass transition temperature (Tg) of 644 K and the crystallization temperature of 763 K, where the stable body-centered tetragonal Zr2Cu phase was formed. In contrast, for the Zr65+xCu17-xNi5Al10Au3 alloys, precipitation of an icosahedral quasicrystalline phase (I-phase) was observed in the supercooled liquid region at about 715 K. HPT deformation of the Zr65Cu17Ni5Al10Au3 alloys was carried out under a high pressure of 5 GPa. Both as-cast specimens and those annealed at Tg-50 K for 90 min were used. Following a single HPT rotation (N=1), transmission electron microscopy identified the presence of face- centered cubic Zr2Ni precipitates in the as-cast alloy, with a size of about 50 nm. For the annealed alloy, a high density of I-phase precipitates with sizes of less than 10 nm was observed following HPT with N=10, indicating that the combination of severe plastic deformation and annealing is effective at producing extremely small grains.

Au-Ag-Cu nano-alloys: tailoring of permittivity

PubMed Central

Hashimoto, Yoshikazu; Seniutinas, Gediminas; Balčytis, Armandas; Juodkazis, Saulius; Nishijima, Yoshiaki

2016-01-01

Precious metal alloys enables new possibilities to tailor materials for specific optical functions. Here we present a systematic study of the effects of a nanoscale alloying on the permittivity of Au-Ag-Cu metals at 38 different atomic mixing ratios. The permittivity was measured and analyzed numerically by applying the Drude model. X-ray diffraction (XRD) revealed the face centered cubic lattice of the alloys. Both, optical spectra and XRD results point towards an equivalent composition-dependent electron scattering behavior. Correlation between the fundamental structural parameters of alloys and the resulting optical properties is elucidated. Plasmonic properties of the Au-Ag-Cu alloy nanoparticles were investigated by numerical simulations. Guidelines for designing plasmonic response of nano- structures and their patterns are presented from the material science perspective. PMID:27118459

Construction of CuS/Au Heterostructure through a Simple Photoreduction Route for Enhanced Electrochemical Hydrogen Evolution and Photocatalysis

PubMed Central

Basu, Mrinmoyee; Nazir, Roshan; Fageria, Pragati; Pande, Surojit

2016-01-01

An efficient Hydrogen evolution catalyst has been developed by decorating Au nanoparticle on the surface of CuS nanostructure following a green and environmental friendly approach. CuS nanostructure is synthesized through a simple wet-chemical route. CuS being a visible light photocatalyst is introduced to function as an efficient reducing agent. Photogenerated electron is used to reduce Au(III) on the surface of CuS to prepare CuS/Au heterostructure. The as-obtained heterostructure shows excellent performance in electrochemical H2 evolution reaction with promising durability in acidic condition, which could work as an efficient alternative for novel metals. The most efficient CuS-Au heterostructure can generate 10 mA/cm2 current density upon application of 0.179 V vs. RHE. CuS-Au heterostructure can also perform as an efficient photocatalyst for the degradation of organic pollutant. This dual nature of CuS and CuS/Au both in electrocatalysis and photocatalysis has been unveiled in this study. PMID:27703212

Isotope geochemistry and fluid inclusion study of skarns from Vesuvius

USGS Publications Warehouse

Gilg, H.A.; Lima, A.; Somma, R.; Belkin, H.E.; de Vivo, B.; Ayuso, R.A.

2001-01-01

We present new mineral chemistry, fluid inclusion, stable carbon and oxygen, as well as Pb, Sr, and Nd isotope data of Ca-Mg-silicate-rich ejecta (skarns) and associated cognate and xenolithic nodules from the Mt. Somma-Vesuvius volcanic complex, Italy. The typically zoned skarn ejecta consist mainly of diopsidic and hedenbergitic, sometimes "fassaitic" clinopyroxene, Mg-rich and Ti-poor phlogopite, F-bearing vesuvianite, wollastonite, gehlenite, meionite, forsterite, clinohumite, anorthite and Mg-poor calcite with accessory apatite, spinell, magnetite, perovskite, baddeleyite, and various REE-, U-, Th-, Zr- and Ti-rich minerals. Four major types of fluid inclusions were observed in wollastonite, vesuvianite, gehlenite, clinopyroxene and calcite: a) primary silicate melt inclusions (THOM = 1000-1050??C), b) CO2 ?? H2S-rich fluid inclusions (THOM = 20-31.3??C into the vapor phase), c) multiphase aqueous brine inclusions (THOM = 720-820??C) with mainly sylvite and halite daughter minerals, and d) complex chloride-carbonate-sulfate-fluoride-silicate-bearing saline-melt inclusions (THOM = 870-890??C). The last inclusion type shows evidence for immiscibility between several fluids (silicate melt - aqueous chloride-rich liquid - carbonate/sulfate melt?) during heating and cooling below 870??C. There is no evidence for fluid circulation below 700??C and participation of externally derived meteoric fluids in skarn formation. Skarns have considerably variable 206Pb/204Pb (19.047-19.202), 207Pb/204Pb (15.655-15.670), and 208Pb/204Pb (38.915-39.069) and relatively low 143Nd/144Nd (0.51211-0.51244) ratios. The carbon and oxygen isotope compositions of skarn calcites (??13CV-PDB = -5.4 to -1.1???; ??18OV-SMOW = 11.7 to 16.4???) indicate formation from a 18O- and 13C-enriched fluid. The isotope composition of skarns and the presence of silicate melt inclusion-bearing wollastonite nodules suggests assimilation of carbonate wall rocks by the alkaline magma at moderate depths (< 5

Atomic structure of water/Au, Ag, Cu and Pt atomic junctions.

PubMed

Li, Yu; Kaneko, Satoshi; Fujii, Shintaro; Nishino, Tomoaki; Kiguchi, Manabu

2017-02-08

Much progress has been made in understanding the transport properties of atomic-scale conductors. We prepared atomic-scale metal contacts of Cu, Ag, Au and Pt using a mechanically controllable break junction method at 10 K in a cryogenic vacuum. Water molecules were exposed to the metal atomic contacts and the effect of molecular adsorption was investigated by electronic conductance measurements. Statistical analysis of the electronic conductance showed that the water molecule(s) interacted with the surface of the inert Au contact and the reactive Cu ant Pt contacts, where molecular adsorption decreased the electronic conductance. A clear conductance signature of water adsorption was not apparent at the Ag contact. Detailed analysis of the conductance behaviour during a contact-stretching process indicated that metal atomic wires were formed for the Au and Pt contacts. The formation of an Au atomic wire consisting of low coordination number atoms leads to increased reactivity of the inert Au surface towards the adsorption of water.

Adsorption Behavior of TBPS in the Process of Cu Electrodeposition on an Au Film.

PubMed

Chen, Liang-Huei; Liu, Yung-Fang; Krug, Klaus; Lee, Yuh-Lang

2018-05-15

The adsorption behavior of an Cu electroplating additive, 3,3 thiobis-(1-propanesulfonic acid sodium salt) (TBPS) in a process of Cu deposition onto a single crystalline Au(111) surface is studied by an in-situ Surface-Enhanced Infrared Absorption Spectroscopy (SEIRAS). The SEIRAS spectra of the TBPS adlayer on a Cu film is investigated first and compared to that on an Au film. These results are utilized to evaluate the characteristics of TBPS adlayer on the electrode surface during the Cu deposition and stripping processes. The results show that the SEIRAS spectra of TBPS adsorbed on the Cu film resembles closely to that on the Au film, and the most pronounced peaks are symmetric S-O (ss-SO) and asymmetric S-O (as-SO) stretching modes. However, the as-SO band is sharper with a higher intensity on the Cu film. Since the ss-SO and as-SO peaks correspond to the molecular with upright and lie-down orientations, respectively, it implies that the TBPS molecules have higher ratio of lie-down orientation on the Cu film. In the Cu electrodeposition process, the cyclic voltammetry (CV) result shows that the presence of the TBPS in the HClO 4 solution can decrease the inhibition effect of HClO 4 to the Cu deposition. For the spectra measured at various potential during cathodic and anodic sweeping, an obvious change of the spectra occurs at ca. 0.6 V, the initiation of Cu underpotential deposition (Cu-UPD). For potentials higher and lower than 0.6 V, the spectra are similar, respectively, to those measured for the Au and Cu films. This result indicates that the TBPS molecules originally adsorbing on the Au film transfer to the surface of deposited Cu layer. This inference is also confirmed by the variation in wavenumber and peak intensity of ss-SO and as-SO peaks during the potential sweeping.

Candidate Elastic Quantum Critical Point in LaCu 6 - x Au x

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poudel, Lekh; May, Andrew F.; Koehler, Michael R.

2016-11-30

In this paper, the structural properties of LaCu 6-xAu x are studied using neutron diffraction, x-ray diffraction, and heat capacity measurements. The continuous orthorhombic-monoclinic structural phase transition in LaCu 6 is suppressed linearly with Au substitution until a complete suppression of the structural phase transition occurs at the critical composition x c=0.3. Heat capacity measurements at low temperatures indicate residual structural instability at x c. The instability is ferroelastic in nature, with density functional theory calculations showing negligible coupling to electronic states near the Fermi level. Finally, the data and calculations presented here are consistent with the zero temperature terminationmore » of a continuous structural phase transition suggesting that the LaCu 6-xAu x series hosts an elastic quantum critical point.« less

Impact of ambient environment on the electronic structure of CuPc/Au sample

NASA Astrophysics Data System (ADS)

Sinha, Sumona; Mukherjee, M.

2018-02-01

The performances of organic devices are crucially connected with their stability in the ambient environment. The impact of 24 h. Ambient environment exposure to the electronic structures of about 12 nm thick CuPc thin film on clean Au substrate have been studied employing UV photoemission spectroscopy technique. X-ray photoemission spectroscopy (XPS) was used to find out the origin of the change of the electronic structures in the sample with the exposure. The XPS study suggests that the oxidation occurs at the CuPc thin film. Due to the adsorption of oxygen in the CuPc film from the ambient air, charge carriers are formed within the CuPc film. Moreover, the XPS results imply that the CuPc film is sufficiently thinner for diffusing oxygen molecules through it and gets physically absorbed on Au substrate during the ambient exposure. Consequently, the hole injection barrier height of pristine CuPc film, grown on Au substrate, is reduced by about 0.50 eV and work-function of the pristine CuPc sample is enhanced by around 0.25 eV in the exposure. The findings will help to understand the mechanism that governs the degradation of performance of CuPc based devices in ambient environment.

A Facile One-Pot Synthesis of Au/Cu2O Nanocomposites for Nonenzymatic Detection of Hydrogen Peroxide

NASA Astrophysics Data System (ADS)

Chen, Ting; Tian, Liangliang; Chen, Yuan; Liu, Bitao; Zhang, Jin

2015-06-01

Au/Cu2O nanocomposites were successfully synthesized by a facile one-pot redox reaction without additional reducing agent under room temperature. The morphologies and structures of the as-prepared products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The electrocatalytic performance of Au/Cu2O nanocomposites towards hydrogen peroxide was evaluated by cyclic voltammetry (CV) and chronoamperometry (CA). The prepared Au/Cu2O nanocomposite electrode showed a wide linear range from 25 to 11.2 mM ( R = 0.9989) with a low detection limit of 1.05 μM ( S/ N = 3) and high sensitivity of 292.89 mA mM-1 cm-2. The enhanced performance for H2O2 detection can be attributed to the introduction of Au and the synergistic effect between Au and Cu2O. It is demonstrated that the Au/Cu2O nanocomposites material could be a promising candidate for H2O2 detection.

Nuclear matter effects on J /ψ production in asymmetric Cu + Au collisions at √{sNN}=200 GeV

NASA Astrophysics Data System (ADS)

Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Aoki, K.; Apadula, N.; Aramaki, Y.; Asano, H.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Bing, X.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Christiansen, P.; Chujo, T.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Ding, L.; Dion, A.; Do, J. H.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; D'Orazio, L.; Engelmore, T.; Enokizono, A.; En'yo, H.; 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.; 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.; Gu, Y.; Gunji, T.; Guragain, H.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Han, S. Y.; Hanks, J.; Hasegawa, S.; Hashimoto, K.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Huang, J.; Huang, S.; Ichihara, T.; Ikeda, Y.; Imai, K.; Imazu, Y.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ivanishchev, D.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, E.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kihara, K.; Kijima, K. M.; Kim, C.; Kim, D. H.; Kim, D. J.; Kim, E.-J.; Kim, H.-J.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kistenev, E.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kofarago, M.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, G. H.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S. H.; Leitch, M. J.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Liu, M. X.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Maruyama, T.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Miller, A. J.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Montuenga, P.; Moon, T.; Morrison, D. P.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nouicer, R.; Novak, T.; Novitzky, N.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Okada, K.; Orjuela Koop, J. D.; Oskarsson, A.; Ozaki, H.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Peng, J.-C.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Purschke, M. L.; Qu, H.; Rak, J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Riveli, N.; Roach, D.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Soumya, M.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takahara, A.; Taketani, A.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, M.; Towell, R.; Towell, R. S.; Tserruya, I.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; Wolin, S.; Woody, C. L.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yanovich, A.; Yokkaichi, S.; Yoon, I.; You, Z.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.; Phenix Collaboration

2014-12-01

We report on J /ψ production from asymmetric Cu + Au heavy-ion collisions at √{sNN}=200 GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of J /ψ yields in Cu + Au collisions in the Au-going direction is found to be comparable to that in Au + Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, J /ψ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-x gluon suppression in the larger Au nucleus.

Photothermal effects from Au-Cu2O core-shell nanocubes, octahedra, and nanobars with broad near-infrared absorption tunability

NASA Astrophysics Data System (ADS)

Wang, Hsiang-Ju; Yang, Kung-Hsun; Hsu, Shih-Chen; Huang, Michael H.

2015-12-01

Other than the display of purely optical phenomenon, the recently-discovered facet-dependent optical properties of metal-Cu2O nanocrystals have become useful by illuminating Au-Cu2O nanocubes and octahedra having a surface plasmon resonance (SPR) absorption band in the near-infrared (NIR) region from octahedral Au cores with 808 nm light for heat generation. After 5 min of light irradiation, a solution of Au-Cu2O nanocubes can reach 65 °C with their Au SPR band matching the illuminating light wavelength. Photothermal efficiency has been found to be facet-dependent. In addition, short gold nanorods were employed to synthesize {100}-bound rectangular Au-Cu2O nanobars with a tunable longitudinal Au SPR absorption band covering a broad NIR range from ~1050 to 1400 nm. Because the Au SPR bands can become fixed with relatively thin Cu2O shells of less than 15 nm, ultrasmall nanobars having a size of 61 nm directly red-shift the Au SPR band to 1047 nm. And 73 nm nanobars can give a Au SPR band at 1390 nm. Truncated nanobars exposing {100}, {110}, and {111} facets give a very blue-shifted Au SPR band. The nanobars also exhibit photothermal activity when illuminated by 1064 nm light. These small Au-Cu2O nanocrystals represent the simplest nanostructure design to absorb light covering the entire NIR wavelengths.Other than the display of purely optical phenomenon, the recently-discovered facet-dependent optical properties of metal-Cu2O nanocrystals have become useful by illuminating Au-Cu2O nanocubes and octahedra having a surface plasmon resonance (SPR) absorption band in the near-infrared (NIR) region from octahedral Au cores with 808 nm light for heat generation. After 5 min of light irradiation, a solution of Au-Cu2O nanocubes can reach 65 °C with their Au SPR band matching the illuminating light wavelength. Photothermal efficiency has been found to be facet-dependent. In addition, short gold nanorods were employed to synthesize {100}-bound rectangular Au-Cu2O nanobars

Structural properties of CuAu nanoparticles with different type. Molecular dynamic simulations

NASA Astrophysics Data System (ADS)

Chepkasov, I. V.; Baidyshev, V. S.; Baev, A. Y.

2018-05-01

The paper is devoted to the thermal stability of a CuAu nanoparticles structure (D=5 nm) of various type (binary alloy, core-shell, "Janus" type) and of various percentage of copper atoms. The simulation was carried out with molecular dynamics, using the embedded atom potential. The authors defined the most preferable structural options from the standpoint of thermodynamics, as well as studied in detail the influence of different temperatures on the structural stability of CuAu nanoparticles.

Angle-resolved investigation of Auger electrons from Cu and Au adsorbed on W(110)

NASA Astrophysics Data System (ADS)

Koshikawa, T.; Von Dem Hagen, T.; Bauer, E.

1981-08-01

The angular distribution of Cu M 2,3VV and Au N 6,7VV Auger electrons from Cu and Au mono- and double layers on W(110) is measured with the goal of obtaining information on the contribution of the backscattered wave on the angular distribution of Auger electrons from adsorbed atoms.

In situ major and trace element analysis of amphiboles in quartz monzodiorite porphyry from the Tonglvshan Cu-Fe (Au) deposit, Hubei Province, China: insights into magma evolution and related mineralization

NASA Astrophysics Data System (ADS)

Duan, Deng-Fei; Jiang, Shao-Yong

2017-05-01

The Tonglvshan deposit is the largest Cu-Fe (Au) skarn deposit in the Edong district, which is located in the westernmost part of the Middle and Lower Yangtze River metallogenic belt, China. In this study, we performed a detailed in situ analysis of major and trace elements in amphiboles from the ore-related Tonglvshan quartz monzodiorite porphyry using electron microprobe (EMPA) analysis and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Two distinct populations of amphiboles, which can be distinguished by their aluminum content, are found in the quartz monzodiorite porphyry. The low-aluminum (Low-Al) amphiboles are subhedral or anhedral and formed at 46.3-73.5 MPa and 713-763 °C. In contrast, the high-aluminum (High-Al) amphiboles are euhedral and formed at 88-165 MPa and 778-854 °C. Some euhedral amphiboles are partially or completely replaced by Low-Al amphibole. The compositions of parental melts in equilibrium with the High-Al amphibole ( Melt 1) and Low-Al amphibole ( Melt 2) were computed by applying solid/liquid partition coefficients. This modeling shows that magma in equilibrium with High-Al amphibole ( Melt 1) underwent 40% fractional crystallization of amphibole, plagioclase and apatite at a depth of 5 km to evolve to magma in equilibrium with Low-Al amphibole ( Melt 2). Copper enrichment occurred in the magma after undergoing fractional crystallization. The magma had a high oxygen fugacity, increasing from NNO + 1 ( Melt 1) through NNO + 2 to HM ( Melt 2), which could have prevented the loss of Cu (and possibly Au) to sulfide minerals during crystallization. Finally, the evolved magma intruded to shallower depths, where it presumably exsolved aqueous ore-forming fluids. Therefore, the large Cu-Fe-Au reserves of the Tonglvshan deposit can likely be attributed to a combination of controlling factors, including high oxygen fugacity, fractional crystallization, fluid exsolution, and a shallow emplacement depth.

Synthesis of Two-Electron Bimetallic Cu-Ag and Cu-Au Clusters by using [Cu13 (S2 CNn Bu2 )6 (C≡CPh)4 ]+ as a Template.

PubMed

Silalahi, Rhone P Brocha; Chakrahari, Kiran Kumarvarma; Liao, Jian-Hong; Kahlal, Samia; Liu, Yu-Chiao; Chiang, Ming-Hsi; Saillard, Jean-Yves; Liu, C W

2018-03-02

Atomically precise Cu-rich bimetallic superatom clusters have been synthesized by adopting a galvanic exchange strategy. [Cu@Cu 12 (S 2 CN n Bu 2 ) 6 (C≡CPh) 4 ][CuCl 2 ] (1) was used as a template to generate compositionally uniform clusters [M@Cu 12 (S 2 CN n Bu 2 ) 6 (C≡CPh) 4 ][CuCl 2 ], where M=Ag (2), Au (3). Structures of 1, 2 and 3 were determined by single crystal X-ray diffraction and the results were supported by ESI-MS. The anatomies of clusters 1-3 are very similar, with a centred cuboctahedral cationic core that is surrounded by six di-butyldithiocarbamate (dtc) and four phenylacetylide ligands. The doped Ag and Au atoms were found to preferentially occupy the centre of the 13-atom cuboctahedral core. Experimental and theoretical analyses of the synthesized clusters revealed that both Ag and Au doping result in significant changes in cluster stability, optical characteristics and enhancement in luminescence properties. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Near-side azimuthal and pseudorapidity correlations using neutral strange baryons and mesons in d + Au , Cu + Cu, and Au + Au collisions at s N N = 200 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abelev, B.; Adamczyk, L.; Adkins, J. K.

Here we present measurements of the near side of triggered di-hadron correlations using neutral strange baryons (more » $$Λ,\\overline{Λ}$$) and mesons (K$$0\\atop{S}$$ ) at intermediate transverse momentum (3 < pT< 6 GeV/c) to look for possible flavor and baryon-meson dependence. This study is performed in d+Au, Cu+Cu, and Au+Au collisions at $$\\sqrt{s}$$$_{NN}$$ = 200 GeV measured by the STAR experiment at RHIC. The near-side di-hadron correlation contains two structures, a peak which is narrow in azimuth and pseudorapidity consistent with correlations from jet fragmentation, and a correlation in azimuth which is broad in pseudorapidity. The particle composition of the jet-like correlation is determined using identified associated particles. The dependence of the conditional yield of the jet-like correlation on the trigger particle momentum, associated particle momentum, and centrality for correlations with unidentified trigger particles are presented. The neutral strange particle composition in jet-like correlations with unidentified charged particle triggers is not well described by PYTHIA. However, the yield of unidentified particles in jet-like correlations with neutral strange particle triggers is described reasonably well by the same model.« less

Near-side azimuthal and pseudorapidity correlations using neutral strange baryons and mesons in d + Au , Cu + Cu, and Au + Au collisions at s N N = 200 GeV

DOE PAGES

Abelev, B.; Adamczyk, L.; Adkins, J. K.; ...

2016-07-28

Here we present measurements of the near side of triggered di-hadron correlations using neutral strange baryons (more » $$Λ,\\overline{Λ}$$) and mesons (K$$0\\atop{S}$$ ) at intermediate transverse momentum (3 < pT< 6 GeV/c) to look for possible flavor and baryon-meson dependence. This study is performed in d+Au, Cu+Cu, and Au+Au collisions at $$\\sqrt{s}$$$_{NN}$$ = 200 GeV measured by the STAR experiment at RHIC. The near-side di-hadron correlation contains two structures, a peak which is narrow in azimuth and pseudorapidity consistent with correlations from jet fragmentation, and a correlation in azimuth which is broad in pseudorapidity. The particle composition of the jet-like correlation is determined using identified associated particles. The dependence of the conditional yield of the jet-like correlation on the trigger particle momentum, associated particle momentum, and centrality for correlations with unidentified trigger particles are presented. The neutral strange particle composition in jet-like correlations with unidentified charged particle triggers is not well described by PYTHIA. However, the yield of unidentified particles in jet-like correlations with neutral strange particle triggers is described reasonably well by the same model.« less

SERS study of surface plasmon resonance induced carrier movement in Au@Cu2O core-shell nanoparticles

NASA Astrophysics Data System (ADS)

Chen, Lei; Zhang, Fan; Deng, Xin-Yu; Xue, Xiangxin; Wang, Li; Sun, Yantao; Feng, Jing-Dong; Zhang, Yongjun; Wang, Yaxin; Jung, Young Mee

2018-01-01

A plasmon induced carrier movement enhanced mechanism of surface-enhanced Raman scattering (SERS) was investigated using a charge-transfer (CT) enhancement mechanism. Here, we designed a strategy to study SERS in Au@Cu2O nanoshell nanoparticles with different shell thicknesses. Among the plasmonically coupled nanostructures, Au spheres with Cu2O shells have been of special interest due to their ultrastrong electromagnetic fields and controllable carrier transfer properties, which are useful for SERS. Au@Cu2O nanoshell nanoparticles (NPs) with shell thicknesses of 48-56 nm are synthesized that exhibit high SERS activity. This high activity originates from plasmonic-induced carrier transfer from Au@Cu2O to 4-mercaptobenzoic acid (MBA). The CT transition from the valence band (VB) of Cu2O to the second excited π-π* transition of MBA, and is of b2 electronic symmetry, which was enhanced significantly. The Herzberg-Teller selection rules were employed to predict the observed enhanced b2 symmetry modes. The system constructed in this study combines the long-range electromagnetic effect of Au NPs, localized surface plasmon resonance (LSPR) of the Au@Cu2O nanoshell, and the CT contribution to assist in understanding the SERS mechanism based on LSPR-induced carrier movement in metal/semiconductor nanocomposites.

Effect of core-shell structure on optical properties of Au-Cu2O nanoparticles

NASA Astrophysics Data System (ADS)

Sai, Cong Doanh; Ngac, An Bang

2018-03-01

Solid Au-Cu2O core-shell nanoparticles were synthesized using gold nanoparticles of 16.6 nm in size as the core. The core-shell structure of the synthesized particles was confirmed and characterized by TEM and HRTEM images. Due to their similar crystal structure, the (111) planes of Cu2O are nucleated and grown epitaxially on the {111} facets of Au nanoparticles with the lattice mismatch of about 4.3% resulting in a polycrystallized Cu2O shell covering the Au nanocore. Due to the quantum confinement effect, the band gap energy Eg of the synthesized Cu2O shells is blue-shifted from 2.35 to 2.70 eV as the shell thickness decreases from of 24.6±3.6 to 9.0±1.7 nm. The localized SPR (Surface Plasmon Resonance) peak of the Au nanocore undergoes a large red shift of the order of a hundred of nm due to both the high refractive index and the increase of the thickness of Cu2O shell. Theoretical models within the Drude framework significantly underestimate the experimental data and predict a wrong rate of change of the SPR peak position with respect to the shell thickness.

Catalytic Gas-Phase Glycerol Processing over SiO2-, Cu-, Ni- and Fe- Supported Au Nanoparticles

PubMed Central

Kapkowski, Maciej; Siudyga, Tomasz; Sitko, Rafal; Lelątko, Józef; Szade, Jacek; Balin, Katarzyna; Klimontko, Joanna; Bartczak, Piotr; Polanski, Jaroslaw

2015-01-01

In this study, we investigated different metal pairings of Au nanoparticles (NPs) as potential catalysts for glycerol dehydration for the first time. All of the systems preferred the formation of hydroxyacetone (HYNE). Although the bimetallics that were tested, i.e., Au NPs supported on Ni, Fe and Cu appeared to be more active than the Au/SiO2 system, only Cu supported Au NPs gave high conversion (ca. 63%) and selectivity (ca. 70%) to HYNE. PMID:26580400

Descriptive and geoenvironmental model for Co-Cu-Au deposits in metasedimentary rocks: Chapter G in Mineral deposit models for resource assessment

USGS Publications Warehouse

Slack, John F.; Johnson, Craig A.; Causey, J. Douglas; Lund, Karen; Schulz, Klaus J.; Gray, John E.; Eppinger, Robert G.; Slack, John F.

2013-01-01

Additional geologically and compositionally similar deposits are known, but have average Co grades less than 0.1 percent. Most of these deposits contain cobalt-rich pyrite and lack appreciable amounts of distinct Co sulfide and (or) sulfarsenide minerals. Such deposits are not discussed in detail in the following sections, but these deposits may be revelant to the descriptive and genetic models presented below. Examples include the Scadding Au-Co-Cu deposit in Ontario, Canada; the Vähäjoki Co-Cu-Au deposit in Finland; the Tuolugou Co-Au deposit in Qinghai Province, China; the Lala Co-Cu-UREE deposit in Sichuan Province, China; the Guelb Moghrein Cu-Au-Co deposit in Mauritania; and the Great Australia Co-Cu, Greenmount Cu-Au-Co, and Monakoff Cu-Au-Co-UAg deposits in Queensland, Australia. Detailed information on these deposits is presented in appendix 2.

Electrochemiluminescence based competitive immunoassay for Sudan I by using gold-functionalized graphitic carbon nitride and Au/Cu alloy nanoflowers.

PubMed

Chen, Wanlu; Yao, Xun; Zhou, Xinchun; Zhao, Kang; Deng, Anping; Li, Jianguo

2018-05-01

A flower-like Au/Cu alloy nanocomposite (Au/Cu NFs) was synthesized and used in an electrochemiluminescence (ECL) based method for sensitive determination of the dye Sudan I. The Au-g-C 3 N 4 nanosheets as an ECL emitter were prepared by electrostatic adsorption between gold nanoparticles and g-C 3 N 4 . They form a film on a glassy carbon electrode (GCE) and then can be connected with Sudan I antigen via gold-nitrogen bond and amidation reactions. The Au/Cu NFs combined with Sudan I antibody also via the Au-N bond and was introduced into the modified GCE by specific recognition between the antibody and the antigen. The overlap between emission spectra of the Au-g-C 3 N 4 nanosheets and absorption spectra of Au/Cu NFs enabled the appearance of ECL resonance energy transfer process. That is, when the Sudan I analyte not present, the ECL was weakened due to absorption by the gray Au/Cu NFs on applying voltages from -1.7 V to 0 V. Conversely, the Au/Cu NFs on the GCE are reduced due to the competition for the antibody between the analyte and the antigen. A strong green ECL emission was obtained. The ECL response is linear in the 0.5 pg mL -1 to 100 ng mL -1 Sudan I concentration range, and the detection limit is 0.17 pg mL -1 . Graphical abstract An Au/Cu alloy flower-like nanocomposite (Au/Cu NFs) is firstly synthesized as an acceptor to constitute an electrochemiluminescence-resonance energy transfer (ECL-RET) system for sensitive measurement of Sudan I, while Au nanoparticles (Au NPs) functionalized graphitic carbon nitride (g-C 3 N 4 ) acted as a donor.

Structural stability, elastic and thermodynamic properties of Au-Cu alloys from first-principles calculations

NASA Astrophysics Data System (ADS)

Kong, Ge-Xing; Ma, Xiao-Juan; Liu, Qi-Jun; Li, Yong; Liu, Zheng-Tang

2018-03-01

Using first-principles calculations method based on density functional theory (DFT) with the Perdew-Burke-Ernzerhof (PBE) implementation of the generalized gradient approximation (GGA), we investigate the structural, elastic and thermodynamic properties of gold-copper intermetallic compounds (Au-Cu ICs). The calculated lattice parameters are in excellent agreement with experimental data. The elastic constants show that all the investigated Au-Cu alloys are mechanically stable. Elastic properties, including the shear modulus, Young's modulus, Poisson's ratio and Pugh's indicator, of the intermetallic compounds are evaluated and discussed, with special attention to the remarkable anisotropy displayed by Au-Cu ICs. Thermodynamic and transport properties including the Debye temperature, thermal conductivity and melting point are predicted from the averaged sound velocity and elastic moduli, using semi-empirical formulas.

Near-side azimuthal and pseudorapidity correlations using neutral strange baryons and mesons in d +Au , Cu + Cu, and Au + Au collisions at √{sN N}=200 GeV

NASA Astrophysics Data System (ADS)

Abelev, B.; Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; Aggarwal, M. M.; Ahammed, Z.; Alekseev, I.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; Attri, A.; Averichev, G. S.; Bai, X.; Bairathi, V.; Barnby, L. S.; Bellwied, R.; Bhasin, A.; Bhati, A. K.; Bhattarai, P.; Bielcik, J.; Bielcikova, J.; Bland, L. C.; Bombara, M.; 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.; Gaillard, L.; Garand, D.; Geurts, F.; Gibson, A.; Girard, M.; Greiner, L.; Grosnick, D.; Gunarathne, D. S.; Guo, Y.; Gupta, A.; Gupta, S.; 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, B.; Huang, X.; Huang, H. Z.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jang, H.; Jentsch, A.; Jia, J.; Jiang, K.; Jones, P. G.; 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, C.; Li, Y.; Li, W.; Li, X.; Li, X.; Lin, T.; Lisa, M. A.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, S.; Luo, X.; Ma, L.; Ma, R.; Ma, G. L.; Ma, Y. G.; Magdy, N.; Majka, R.; Manion, A.; Margetis, S.; Markert, C.; Matis, H. S.; McDonald, D.; McKinzie, S.; Meehan, K.; Mei, J. C.; Miller, Z. W.; Minaev, N. G.; Mioduszewski, S.; Mishra, D.; Mohanty, B.; Mondal, M. M.; Morozov, D. A.; Mustafa, M. K.; Nandi, B. K.; Nattrass, C.; 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.; 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, B.; Sharma, A.; 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, Y.; Sun, Z.; Sun, X. M.; 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, H.; Wang, Y.; Wang, G.; Wang, Y.; Wang, J. S.; Wang, F.; 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, J.; Xu, H.; Xu, Z.; Yang, Y.; Yang, Q.; Yang, S.; Yang, Y.; Yang, Y.; Yang, C.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, S.; Zhang, X. P.; Zhang, Y.; Zhang, S.; Zhang, J. B.; Zhang, J.; Zhang, J.; Zhang, Z.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

2016-07-01

We present measurements of the near side of triggered di-hadron correlations using neutral strange baryons (Λ ,Λ ¯) and mesons (KS0) at intermediate transverse momentum (3 < pT <6 GeV /c ) to look for possible flavor and baryon-meson dependence. This study is performed in d +Au , Cu+Cu, and Au+Au collisions at √{sN N}=200 GeV measured by the STAR experiment at RHIC. The near-side di-hadron correlation contains two structures, a peak which is narrow in azimuth and pseudorapidity consistent with correlations from jet fragmentation, and a correlation in azimuth which is broad in pseudorapidity. The particle composition of the jet-like correlation is determined using identified associated particles. The dependence of the conditional yield of the jet-like correlation on the trigger particle momentum, associated particle momentum, and centrality for correlations with unidentified trigger particles are presented. The neutral strange particle composition in jet-like correlations with unidentified charged particle triggers is not well described by PYTHIA. However, the yield of unidentified particles in jet-like correlations with neutral strange particle triggers is described reasonably well by the same model.

Elevated temperature creep and fracture properties of the 62Cu-35Au-3Ni braze alloy

NASA Astrophysics Data System (ADS)

Stephens, J. J.; Greulich, F. A.

1995-06-01

The Cu-Au-Ni braze alloys are used for metal/ceramic brazes in electronic assemblies because of their good wetting characteristics and low vapor pressure. We have studied the tensile creep properties of annealed 62Cu-35Au-3Ni alloy over the temperature range 250 °C to 750 °C. Two power-law equations have been developed for the minimum creep rate as a function of true stress and temperature. At the highest temperatures studied (650 °C and 750 °C), the minimum creep rate is well described with a stress exponent of 3.0, which can be rationalized in the context of Class I solid solution strengthening. The inverted shape of the creep curves observed at these temperatures is also consistent with Class I alloy behavior. At lower temperatures, power-law creep is well described with a stress exponent of 7.5, and normal three-stage creep curves are observed. Intergranular creep damage, along with minimum values of strain to fracture, is most apparent at 450 °C and 550 °C. The lower stress exponent in the Class I alloy regime helps to increase the strain to fracture at higher temperatures (650 °C and 750 °C). The minimum creep rate behavior of the 62Cu-35Au-3Ni alloy is also compared with those of the 74.2Cu-25. 8Au alloy and pure Cu. This comparison indicates that the 62Cu-35Au-3Ni has considerably higher creep strength than pure Cu. This fact suggests that the 62Cu-35Au-3Ni braze alloy can be used in low mismatch metal-to-ceramic braze joints such as Mo to metallized alumina ceramic with few problems. However, careful joint design may be essential for the use of this alloy in high thermal mismatch metal-to-ceramic braze joints.

Participant and spectator scaling of spectator fragments in Au + Au and Cu + Cu collisions at √{sN N}=19.6 and 22.4 GeV

NASA Astrophysics Data System (ADS)

Alver, B.; 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.; Chetluru, V.; Decowski, M. P.; García, E.; Gburek, T.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Harnarine, I.; 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.; Li, W.; Lin, W. T.; Loizides, C.; 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.; Richardson, E.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Sedykh, I.; Skulski, W.; Smith, C. E.; Stankiewicz, M. A.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Szostak, A.; Tang, J.-L.; Tonjes, M. B.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Vaurynovich, S. S.; Verdier, R.; Veres, G. I.; Walters, P.; Wenger, E.; Willhelm, D.; Wolfs, F. L. H.; Wosiek, B.; Woźniak, K.; Wuosmaa, A. H.; Wyngaardt, S.; Wysłouch, B.; Phobos Collaboration

2016-08-01

Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen (Z =7 ), are measured in PHOBOS. These fragments are observed in Au+Au (√{sNN}=19.6 GeV ) and Cu+Cu (22.4 GeV) collisions at high pseudorapidity (η ). The dominant multiply-charged fragment is the tightly bound helium (α ), with lithium, beryllium, and boron all clearly seen as a function of collision centrality and pseudorapidity. We observe that in Cu+Cu collisions, it becomes much more favorable for the α fragments to be released than lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. A detailed comparison of the shapes for α and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.

Magma Fertility is the First-Order Factor for the Formation of Porphyry Cu±Au Deposits

NASA Astrophysics Data System (ADS)

Park, J. W.; Campbell, I. H.; Malaviarachchi, S. P. K.; Cocker, H.; Nakamura, E.; Kay, S. M.

2017-12-01

Magma fertility, the metal abundance in magma, has been considered to be one of the key factors for the formation of porphyry Cu±Au deposits. In this study we provide clear evidence to support the hypothesis that the platinum group element (PGE) can be used to distinguish barren from ore-bearing Cu±Au felsic suites. We determined the PGE contents of three barren volcanic and subvolcanic suites from Argentina and Japan, and compare the results with two porphyry Cu-bearing subvolcanic suites from Chile and two porphyry Cu-Au-bearing suites from Australia. The barren suites are significantly depleted in PGE abundances by the time of fluid exsolution, which is attributed to early sulfide saturation at mid to lower crust depths or assimilation of chalcophile element-poor crustal materials. Barren magma, produced by melting continental crust, may have been initially deficient in chalcophile elements. In contrast, the Cu±Au ore-bearing suites contain at least an order of magnitude higher PGE contents than those of the barren suites by the time of fluid saturation. They are characterized by late sulfide saturation in a shallow magma chamber, which allows the chalcophile elements to concentrate in the fractionating magma from which they are sequestered by ore-forming fluids. We suggest the Pd/MgO and Pd/Pt ratios of igneous rocks can be used as magma fertility indicators, and to distinguish between barren, porphyry Cu and porphyry Cu-Au magmatic systems.

Participant and spectator scaling of spectator fragments in Au + Au and Cu + Cu collisions at s N N = 19.6 and 22.4 GeV

DOE PAGES

Alver, B.; Back, B. B.; Baker, M. D.; ...

2016-08-02

Specmore » tator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen (Z = 7), are measured in PHOBOS. These fragments are observed in Au+Au ( s N N = 19.6 GeV) and Cu+Cu (22.4 GeV) collisions at high pseudorapidity (η). The dominant multiply-charged fragment is the tightly bound helium (α), with lithium, beryllium, and boron all clearly seen as a function of collision centrality and pseudorapidity. In this paper, we observe that in Cu+Cu collisions, it becomes much more favorable for the α fragments to be released than lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. Finally, a detailed comparison of the shapes for α and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.« less

40Ar-39Ar dating of Archean iron oxide Cu-Au and Paleoproterozoic granite-related Cu-Au deposits in the Carajás Mineral Province, Brazil: implications for genetic models

NASA Astrophysics Data System (ADS)

Pollard, Peter J.; Taylor, Roger G.; Peters, Lisa; Matos, Fernando; Freitas, Cantidiano; Saboia, Lineu; Huhn, Sergio

2018-05-01

40Ar-39Ar dating of biotite from IOCG and granite-related Cu-Au deposits in the Carajás Mineral Province provides evidence for the timing of mineralization and constraints on genetic models of ore formation. Ages of biotite from greisen and quartz-rich vein and breccia deposits, Alvo 118—1885 ± 4 Ma, Breves—1886 ± 5 Ma, Estrela—1896 ± 7 Ma, and Gameleira—1908 ± 7 Ma, demonstrate the close temporal relationship between Cu-Au mineralization and subjacent A-type granites. Mineralization is hosted within granite cupolas (Breves) or in vein/breccia systems emanating from the cupolas (Estrela and Gameleira), consistent with a genetic relationship of mineralization to the B-Li-F-rich granites. Plateau and minimum ages of biotite from IOCG deposits, including Igarapé Bahia, Cristalino, Corta Goela, and GT34, range from 2537 ± 6 Ma to 2193 ± 4 Ma. The 40Ar-39Ar age of biotite from Igarapé Bahia (2537 ± 6 Ma) is similar to a previous SHRIMP 207Pb-206Pb age for monazite of 2575 ± 12 Ma when the uncertainties in the respective analyses and standards are taken into account. The age spectrum for biotite from Cristalino shows increasing ages for successive steps, consistent with post-crystallization Ar loss, and the age of 2388 ± 5 Ma for the last three steps is considered a minimum age for Cu-Au mineralization. The age of biotite from the GT34 prospect (2512 ± 7 Ma) coincides with a previously identified period of basement reactivation and may indicate the formation of Cu-Au mineralization at this time or resetting of biotite from an older mineralization event at this time. At Corta Goela, within the Canaã Shear Zone, the biotite age of 2193 ± 4 Ma lies between the ages of IOCG (2.57-2.76 Ga) and granite-related Cu-Au ( 1.88 Ga) deposits elsewhere in the Carajás district but is similar to previously reported 40Ar-39Ar ages for amphibole from Sossego, possibly indicating that mineralization at both Sossego and Corta Goela was affected by a thermal event at

Cu-Au alloy nanostructures coated with aptamers: a simple, stable and highly effective platform for in vivo cancer theranostics

NASA Astrophysics Data System (ADS)

Ye, Xiaosheng; Shi, Hui; He, Xiaoxiao; Yu, Yanru; He, Dinggeng; Tang, Jinlu; Lei, Yanli; Wang, Kemin

2016-01-01

As a star material in cancer theranostics, photoresponsive gold (Au) nanostructures may still have drawbacks, such as low thermal conductivity, irradiation-induced melting effect and high cost. To solve the problem, copper (Cu) with a much higher thermal conductivity and lower cost was introduced to generate a novel Cu-Au alloy nanostructure produced by a simple, gentle and one-pot synthetic method. Having the good qualities of both Cu and Au, the irregularly-shaped Cu-Au alloy nanostructures showed several advantages over traditional Au nanorods, including a broad and intense near-infrared (NIR) absorption band from 400 to 1100 nm, an excellent heating performance under laser irradiation at different wavelengths and even a notable photostability against melting. Then, via a simple conjugation of fluorophore-labeled aptamers on the Cu-Au alloy nanostructures, active targeting and signal output were simultaneously introduced, thus constructing a theranostic platform based on fluorophore-labeled, aptamer-coated Cu-Au alloy nanostructures. By using human leukemia CCRF-CEM cancer and Cy5-labeled aptamer Sgc8c (Cy5-Sgc8c) as the model, a selective fluorescence imaging and NIR photothermal therapy was successfully realized for both in vitro cancer cells and in vivo tumor tissues. It was revealed that Cy5-Sgc8c-coated Cu-Au alloy nanostructures were not only capable of robust target recognition and stable signal output for molecular imaging in complex biological systems, but also killed target cancer cells in mice with only five minutes of 980 nm irradiation. The platform was found to be simple, stable, biocompatible and highly effective, and shows great potential as a versatile tool for cancer theranostics.As a star material in cancer theranostics, photoresponsive gold (Au) nanostructures may still have drawbacks, such as low thermal conductivity, irradiation-induced melting effect and high cost. To solve the problem, copper (Cu) with a much higher thermal conductivity

Concomitant skarn and syenitic magma evolution at the margins of the Zippa Mountain pluton

NASA Astrophysics Data System (ADS)

Coulson, I. M.; Westphal, M.; Anderson, R. G.; Kyser, T. K.

2007-07-01

Zippa Mountain pluton is a Mesozoic concentrically-zoned intrusion, located within the Canadian Cordillera of British Columbia. An extensive phase of K-feldspar bearing syenite grades towards its margins to mela-syenite and clinopyroxenite. This simple pattern of petrological zonation is overprinted by localised occurrences of silica-undersaturated, peralkaline rock types. High-purity wollastonite skarns occur within and peripheral to the intrusion and result from extensive interaction between intrusion-related fluids and Permian limestone/marble, at shallow crustal levels. Field, chemical and isotopic studies provide insights into interaction between a parental syenitic magma and these country rocks. To achieve this, petrological studies of four of the skarn bodies present have been combined with chemical and isotopic data from the pluton, and from drill core through the skarn into the pluton, to reconstruct the stages in the development of wollastonite skarn and progressive magma-country rock interaction. Derivation of peralkaline compositions from the syenitic magma requires either a loss of Si and Al, or addition of Na and/or K. Our studies preclude the addition of alkali elements but highlight extensive Si-infiltration into the limestone, while the conversion of marble to grossular-andradite skarn, indicates Al-infiltration. Fluid egress resulted in de-silicification/de-alumination of the Zippa Mountain magmas, and increased peralkalinity; wollastonite and garnet-bearing skarn formed as a by-product. Hence, the development of peralkaline rock compositions at Zippa Mountain required a parental syenitic magma, and reaction and/or interaction with calcareous country rocks.

Evolution of borate minerals from contact metamorphic to hydrothermal stages: Ludwigite-group minerals and szaibélyite from the Vysoká - Zlatno skarn, Slovakia

NASA Astrophysics Data System (ADS)

Bilohuščin, Vladimír; Uher, Pavel; Koděra, Peter; Milovská, Stanislava; Mikuš, Tomáš; Bačík, Peter

2017-09-01

Borate minerals of the ludwigite group (LGM) and szaibélyite in association with hydroxylclinohumite, clinochlore, a serpentine mineral, magnesian magnetite, spinel, magnesite, dolomite and sulphide minerals, occur in a magnesian exoskarn in the R-20 borehole located in the Vysoká - Zlatno Cu-Au porphyry-skarn deposit, located within the Štiavnica Neogene stratovolcano, Western Carpathians, central Slovakia. The skarn is developed along the contact of Miocene granodiorite to quartz-diorite porphyry and a Middle-Upper Triassic dolomite-shale-psammite-anhydrite sedimentary sequence. The boron minerals were investigated by electron probe micro-analyser (EPMA) and micro-Raman techniques. The source of boron could have been from the granodiorite/quartz diorite intrusion; however some supply of B from adjacent evaporite-bearing sediments is also possible. Based on textural and compositional data, the minerals originated during two stages. (1) An early high-temperature, contact-metamorphic and metasomatic stage comprises coarse-crystalline aggregate of LGM (types 1 to 3) in association with hydroxylclinohumite, magnetite, and rarely spinel inclusions in LGM. Compositional variations of LGM show a crystallization sequence from early azoproite [≤17 wt% TiO2; 0.40 atoms pre formula unit (apfu) Ti, which correspond to ≤79 mol% of the Mg2(Mg0.5Ti0.5)O2(BO3) end-member], Ti-Al-rich members of LGM, "aluminoludwigite "[≤14 wt% Al2O3; ≤0.53 apfu, ≤53 mol% of Mg2AlO2(BO3) end-member] and Al-rich ludwigite in the central zone of crystals, to Ti-Al-poor ludwigite in outer parts of crystals. (2) Minerals of the late retrograde serpentinization and hydrothermal stage form irregular veinlets and aggregates, including partial alteration of hydroxylclinohumite to the serpentine-group mineral and clinochlore, replacement of LGM by szaibélyite, formation of the latest generation of Fe-rich, Ti-Al poor ludwigite in veinlets (type 4), and precipitation of dolomite, magnesite and

Nuclear matter effects on J/ψ production in asymmetric Cu + Au collisions at \\(\\sqrt{s_{\\mathrm{NN}}} = 200\\) GeV

DOE PAGES

Adare, A.; Aidala, C.; Ajitanand, N. N.; ...

2014-12-18

We report on J/ψ production from asymmetric Cu+Au heavy-ion collisions at \\(\\sqrt{s_{\\mathrm{NN}}} = 200\\) GeV at the Relativistic Heavy Ion Collider at both forward (Cu-going direction) and backward (Au-going direction) rapidities. The nuclear modification of J/ψ yields in Cu+Au collisions in the Au-going direction is found to be comparable to that in Au+Au collisions when plotted as a function of the number of participating nucleons. In the Cu-going direction, J/ψ production shows a stronger suppression. This difference is comparable in magnitude and has the same sign as the difference expected from shadowing effects due to stronger low-x gluon suppression inmore » the larger Au nucleus. Thus, the relative suppression is opposite to that expected from hot nuclear matter dissociation, since a higher energy density is expected in the Au-going direction.« less

Structure formation in Ag-X (X = Au, Cu) alloys synthesized far-from-equilibrium

NASA Astrophysics Data System (ADS)

Elofsson, V.; Almyras, G. A.; Lü, B.; Garbrecht, M.; Boyd, R. D.; Sarakinos, K.

2018-04-01

We employ sub-monolayer, pulsed Ag and Au vapor fluxes, along with deterministic growth simulations, and nanoscale probes to study structure formation in miscible Ag-Au films synthesized under far-from-equilibrium conditions. Our results show that nanoscale atomic arrangement is primarily determined by roughness build up at the film growth front, whereby larger roughness leads to increased intermixing between Ag and Au. These findings suggest a different structure formation pathway as compared to the immiscible Ag-Cu system for which the present study, in combination with previously published data, reveals that no significant roughness is developed, and the local atomic structure is predominantly determined by the tendency of Ag and Cu to phase-separate.

Growth of periodic nano-layers of nano-crystals of Au, Ag, Cu by ion beam

NASA Technical Reports Server (NTRS)

Smith, Cydale C.; Zheng, B.; Muntele, C. I.; Muntele, I. C.; Ila, D.

2005-01-01

Multilayered thin films of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/, were grown by deposition. We have previously shown that MeV ion Bombardment of multi-nano-layers of SiO2/AU+ SiO2/ produces Au nanocrystals in the AU+ SiO2 layers. An increased number of nano-layers followed by MeV ion bombardment produces a wide optical absorption band, of which its FWHM depends on the number of nano-layers of SiO2/AU+ SiO2/. We have successfully repeated this process for nano-layers of SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/. In this work we used 5 MeV Si as the post deposition bombardment ion and monitored the location as well as the optical absorption's FWHM for each layered structure using Optical Absorption Photospectrometry. The concentration and location of the metal nano-crystals were measured by Rutherford Backscattering Spectrometry. We will report on the results obtained for nano-layered structures produced by post deposition bombardment of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/ layered systems as well as the results obtained from a system containing a periodic combination of SiO2/AU+ SiO2/, SiO2/Ag+ SiO2/, and SiO2/Cu+ SiO2/.

Wetting reaction of Sn-Ag based solder systems on Cu substrates plated with Au and/or Pd layer

NASA Astrophysics Data System (ADS)

Liu, C. Y.; Li, Jian; Vandentop, G. J.; Choi, W. J.; Tu, K. N.

2001-05-01

The wetting behavior of SnAg based Pb-free solders on Cu and Cu substrates plated with Au, Pd, and Au/Pd thin films have been studied. The wetting angle and kinetics of interfacial reaction were measured. The Au-plated substrates exhibit better wetting than the Pd-plated substrates. In the case of SnAg on Pd-plated Cu, SEM observation revealed that the solder cap was surrounded by an innerring of Cu-Sn compound and an outer ring of Pd-Sn compound. This implies that the molten SnAg solder had removed the Pd and wetted the Cu directly in the equilibrium state. The effects of pre-doping Cu in the SnAg solder on wetting behavior were also investigated. We found that wettability decreases with increasing Cu content in the solder. We also observed that the SnAgCu solders have a lower Cu consumption rate than the SnAg solder.

The surface plasmon-induced hot carrier effect on the catalytic activity of CO oxidation on a Cu2O/hexoctahedral Au inverse catalyst.

PubMed

Lee, Si Woo; Hong, Jong Wook; Lee, Hyunhwa; Wi, Dae Han; Kim, Sun Mi; Han, Sang Woo; Park, Jeong Young

2018-06-14

The intrinsic correlation between an enhancement of catalytic activity and the flow of hot electrons generated at metal-oxide interfaces suggests an intriguing way to control catalytic reactions and is a significant subject in heterogeneous catalysis. Here, we show surface plasmon-induced catalytic enhancement by the peculiar nanocatalyst design of hexoctahedral (HOH) Au nanocrystals (NCs) with Cu2O clusters. We found that this inverse catalyst comprising a reactive oxide for the catalytic portion and a metal as the source of electrons by localized surface plasmon resonance (localized SPR) exhibits a change in catalytic activity by direct hot electron transfer or plasmon-induced resonance energy transfer (PIRET) when exposed to light. We prepared two types of inverse catalysts, Cu2O at the vertex sites of HOH Au NCs (Cu2O/Au vertex site) and a HOH Au NC-Cu2O core-shell structure (HOH Au@Cu2O), to test the structural effect on surface plasmons. Under broadband light illumination, the Cu2O/Au vertex site catalyst showed 30-90% higher catalytic activity and the HOH Au@Cu2O catalyst showed 10-30% higher catalytic activity than when in the dark. Embedding thin SiO2 layers between the HOH Au NCs and the Cu2O verified that the dominant mechanism for the catalytic enhancement is direct hot electron transfer from the HOH Au to the Cu2O. Finite-difference time domain calculations show that a much stronger electric field was formed on the vertex sites after growing the Cu2O on the HOH Au NCs. These results imply that the catalytic activity is enhanced when hot electrons, created from photon absorption on the HOH Au metal and amplified by the presence of surface plasmons, are transferred to the reactive Cu2O.

Pt skin on AuCu intermetallic substrate: a strategy to maximize Pt utilization for fuel cells.

PubMed

Wang, Gongwei; Huang, Bing; Xiao, Li; Ren, Zhandong; Chen, Hao; Wang, Deli; Abruña, Héctor D; Lu, Juntao; Zhuang, Lin

2014-07-09

The dependence on Pt catalysts has been a major issue of proton-exchange membrane (PEM) fuel cells. Strategies to maximize the Pt utilization in catalysts include two main approaches: to put Pt atoms only at the catalyst surface and to further enhance the surface-specific catalytic activity (SA) of Pt. Thus far there has been no practical design that combines these two features into one single catalyst. Here we report a combined computational and experimental study on the design and implementation of Pt-skin catalysts with significantly improved SA toward the oxygen reduction reaction (ORR). Through screening, using density functional theory (DFT) calculations, a Pt-skin structure on AuCu(111) substrate, consisting of 1.5 monolayers of Pt, is found to have an appropriately weakened oxygen affinity, in comparison to that on Pt(111), which would be ideal for ORR catalysis. Such a structure is then realized by substituting the Cu atoms in three surface layers of AuCu intermetallic nanoparticles (AuCu iNPs) with Pt. The resulting Pt-skinned catalyst (denoted as Pt(S)AuCu iNPs) has been characterized in depth using synchrotron XRD, XPS, HRTEM, and HAADF-STEM/EDX, such that the Pt-skin structure is unambiguously identified. The thickness of the Pt skin was determined to be less than two atomic layers. Finally the catalytic activity of Pt(S)AuCu iNPs toward the ORR was measured via rotating disk electrode (RDE) voltammetry through which it was established that the SA was more than 2 times that of a commercial Pt/C catalyst. Taking into account the ultralow Pt loading in Pt(S)AuCu iNPs, the mass-specific catalytic activity (MA) was determined to be 0.56 A/mg(Pt)@0.9 V, a value that is well beyond the DOE 2017 target for ORR catalysts (0.44 A/mg(Pt)@0.9 V). These findings provide a strategic design and a realizable approach to high-performance and Pt-efficient catalysts for fuel cells.

Efficient CH3NH3PbI3 perovskite/fullerene planar heterojunction hybrid solar cells with oxidized Ni/Au/Cu transparent electrode

NASA Astrophysics Data System (ADS)

Lai, Wei-Chih; Lin, Kun-Wei; Guo, Tzung-Fang; Chen, Peter; Liao, Yuan-Yu

2018-02-01

We demonstrated the performance of inverted CH3NH3PbI3 perovskite-based solar cells (SCs) with a thermally oxidized nickel/gold/copper (Ni/Au/Cu) trilayer transparent electrode. Oxidized Ni/Au/Cu is a high transparent layer and has less resistance than the oxidized Ni/Au layer. Like the oxidized Ni/Au layer, oxidized Ni and Cu in oxidized Ni/Au/Cu could perform as a hole transport layer of the perovskite-based SCs. It leads to improved perovskite SC performance on an open circuit voltage of 1.01 V, a short circuit current density of 14.36 mA/cm2, a fill factor of 76.7%, and a power conversion efficiency (η%) of 11.1%. The η% of perovskite SCs with oxidized Ni (10 nm)/Au (6 nm)/Cu (1 nm) improved by approximately 10% compared with that of perovskite SCs with oxidized Ni/Au.

Molecular oxygen adsorption and dissociation on Au12M clusters with M = Cu, Ag or Ir

NASA Astrophysics Data System (ADS)

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

2018-03-01

In this work, we present a density functional theory study of the structural and electronic properties of isolated neutral clusters of the type Au12M, with M = Cu, Ag, or Ir. On the other hand, there is experimental evidence that gold-silver, gold-copper and gold-iridium nanoparticles have an enhanced catalytic activity for the CO oxidation reaction. In order to address these phenomena, we also performed density functional calculations of the adsorption and dissociation of O2 on these nanoparticles. Moreover, to understand the effects of Cu, Ag, and Ir impurity atoms on the dissociation of O2, we also analyze this reaction in the corresponding pure gold cluster. The results indicate that the substitution of one gold atom in a Au13 cluster by Ag, Cu or Ir diminishes the activation energy barrier for the O2 dissociation by nearly 1 eV. This energy barrier is similar for Au12Ag and Au12Cu, whereas for Au12Ir is even lower. These results suggest that the addition of other transition metal atoms to gold nanoclusters can enhance their catalytic activity towards the CO oxidation reaction, independently of the effect that the substrate could have on supported nanoclusters.

Tin-phthalocyanine adsorption and diffusion on Cu and Au (111) surfaces: A density functional theory study

NASA Astrophysics Data System (ADS)

Qin, Dan; Ge, Xu-Jin; Lü, Jing-Tao

2018-05-01

Through density functional theory based calculations, we study the adsorption and diffusion of tin phthalocyanine (SnPc) molecule on Au(111) and Cu(111) surfaces. SnPc has two conformers with Sn pointing to the vacuum (Sn-up) and substrate (Sn-down), respectively. The binding energies of the two conformers with different adsorption sites on the two surfaces, including top, bridge, fcc, hcp, are calculated and compared. It is found that the SnPc molecule binds stronger on Cu(111) surface, with binding energy about 1 eV larger than that on Au(111). Only the bridge and top adsorption sites are stable on Cu(111), while all the four adsorption sites are stable on Au(111), with small diffusion barriers between them. Moreover, the flipping barrier from Sn-up to Sn-down conformer is of the same magnitude on the two metal surfaces. These results are consistent with a recent experiment [Zhang, et al., Angew. Chem., 56, 11769 (2017)], which shows that conformation change from Sn-up to Sn-down on Cu(111) surface can be induced by a C60-functionalized STM tip, while similar change is difficult to realize on Au(111), due to smaller diffusion barrier on Au(111).

Interaction of intermetallic compound formation in Cu/SnAgCu/NiAu sandwich solder joints

NASA Astrophysics Data System (ADS)

Xia, Yanghua; Lu, Chuanyan; Chang, Junling; Xie, Xiaoming

2006-05-01

The interaction between Cu/solder interface and solder/Ni interface at a Cu/SnAgCu/NiAu sandwich solder joint with various surface finishes and solder heights was investigated. The interfacial microstructure and composition of intermetallic compounds (IMCs) were characterized by a scanning electron microscope (SEM) equipped with energy-dispersive x-ray spectroscopy (EDX). The phase structure of IMC was identified by x-ray diffraction (XRD). It is found that ternary (Cu,Ni)6Sn5 IMCs form at both interfaces. The composition, thickness, and morphology of the ternary IMCs depend not only on the interface itself, but also on the opposite interface. That is to say, strong coupling effects exist between the two interfaces. Lattice parameters of (Cu,Ni)6Sn5 shrink with increasing Ni content, in agreement with Vegard’s law. The mechanism of ternary IMC formation and interface coupling effects are discussed in this paper.

Partial-melting of fertile metasedimentary rocks controlling the ore formation in the Jiangnan porphyry-skarn tungsten belt, south China: A case study at the giant Zhuxi W-Cu skarn deposit

NASA Astrophysics Data System (ADS)

Song, Shiwei; Mao, Jingwen; Zhu, Yongfeng; Yao, Zaiyu; Chen, Guohua; Rao, Jianfeng; Ouyang, Yongpeng

2018-04-01

The Zhuxi W-Cu deposit, located in the Jiangnan porphyry-skarn W belt, is a world-class W deposit. We studied three coeval mineralization-related intrusions composed of biotite monzogranite, fine-grained granite, and granite porphyry in the Zhuxi mine. These rocks contain peritectic garnet and K-feldspar. The LA-ICP-MS U-Pb dating of zircon from the biotite monzogranite, fine-grained granite, and granite porphyry yields average ages of 149.38 ± 0.86 Ma, 149.0 ± 1.0 Ma, and 148.30 ± 1.4 Ma, respectively. The Zhuxi granites are enriched in Cs, Rb, and U and depleted in Ba, Sr, and Ti, with ASI [molar Al2O3 / (CaO + Na2O + K2O)] values of 1.03-2.15. The fine-grained granite exhibits initial 87Sr/86Sr values of 0.716-0.717 and εNd(t) values ranging from -9.61 to -9.21. The εHf(t) values of the biotite monzogranite and fine-grained granite range from -8.83 to -6.30 and from -9.86 to -7.62, respectively. The Sr-Nd-Hf isotopic compositions of these rocks are similar to those of the fertile Neoproterozoic metasedimentary rocks in the Jiangnan W belt. The Zhuxi granites are S-type granites based on their mineral assemblages and geochemical characteristics. The Hf isotopic compositions, Sr-Nd isotopic characteristics, and trace element modelling suggest that the studied granites formed from the dehydration melting of fertile Neoproterozoic metasedimentary rocks caused by the Late Jurassic underplating of OIB-like basaltic magma.

Cu, Ag, Au: Electrical Resistivity Along their Melting Boundaries

NASA Astrophysics Data System (ADS)

Secco, R.; Littleton, J. A. H.; Berrada, M.; Ezenwa, I.; Yong, W.

2017-12-01

Electrical resistivity of Cu, Ag and Au was measured at pressures up to 5 GPa and temperatures up to 300 K above melting in a 1000-ton cubic anvil press. Two W/Re thermocouples placed at opposite ends of the wire sample served as T probes as well as 4-wire resistance electrodes in a switched circuit. A polarity switch was also used to remove any bias associated with current flow and voltage measurement using thermocouple legs. Examination of the composition of recovered and sectioned samples was carried out using electron microprobe analyses. Melting temperatures at high pressures were determined from the large jump in resistivity on heating at constant pressure and these agree well with previous experimental and theoretical phase diagram studies. With increasing P and T, electrical resistivity behavior in these noble metals is consistent with 1atm data. The resistivity values at the melting temperature of Cu and Ag decrease with increasing high pressure and Au seems to behave similarly. The results are compared to prediction by Stacey and Anderson (PEPI, 2001).

Secondary ion mass spectroscopy study of Au trapping and migration in the Au-irradiated YBa2Cu3O7 - delta film

NASA Astrophysics Data System (ADS)

Li, Yupu; Kilner, J. A.; Liu, J. R.; Chu, W. K.; Wagner, G. A.; Somekh, R. E.

1996-05-01

The range data and migration of Au in YBa2Cu3O7-δ film were studied with implanted 197Au (1.5 MeV 5×1015 Au+/cm2) as a tracer. The film was a c-axis oriented film, ˜750 nm thick, deposited by high-pressure planar dc sputtering on <100> LaAlO3. Analysis by secondary ion mass spectroscopy shows that the as-implanted Au concentration distribution is essentially Gaussian-like and the depth (R̂p) of maximum Au concentration (˜1.2 wt %) is 201 nm. The projected range (R¯p) and (R̂p) are found to be in very good agreement with the simulated data by TRIM-95, whereas the measured ``straggle'' (ΔRp*) is about 20% larger than that by TRIM-95 simulation. It has also been found that the implanted 197Au starts to migrate within the film at a temperature between 650 and 700 °C, which is much higher than that for the implanted 2H (˜175 °C) and the implanted 18O (between 250 and 300 °C) in c-oriented YBa2Cu3O7-δ films.

Combination of surface- and interference-enhanced Raman scattering by CuS nanocrystals on nanopatterned Au structures

PubMed Central

Yeryukov, Nikolay A; Sveshnikova, Larisa L; Duda, Tatyana A; Rodyakina, Ekaterina E; Gridchin, Victor A; Sheremet, Evgeniya S; Zahn, Dietrich R T

2015-01-01

Summary We present the results of a Raman study of optical phonons in CuS nanocrystals (NCs) with a low areal density fabricated through the Langmuir–Blodgett technology on nanopatterned Au nanocluster arrays using a combination of surface- and interference-enhanced Raman scattering (SERS and IERS, respectively). Micro-Raman spectra of one monolayer of CuS NCs deposited on a bare Si substrate reveal only features corresponding to crystalline Si. However, a new relatively strong peak occurs in the Raman spectrum of CuS NCs on Au nanocluster arrays at 474 cm−1. This feature is related to the optical phonon mode in CuS NCs and manifests the SERS effect. For CuS NCs deposited on a SiO2 layer this phonon mode is also observed due to the IERS effect. Its intensity changes periodically with increasing SiO2 layer thickness for different laser excitation lines and is enhanced by a factor of about 30. CuS NCs formed on Au nanocluster arrays fabricated on IERS substrates combine the advantages of SERS and IERS and demonstrate stronger SERS enhancement allowing for the observation of Raman signals from CuS NCs with an ultra-low areal density. PMID:25977845

Φ meson production in the forward/backward rapidity region in Cu + Au collisions at s NN = 200 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adare, A.; Aidala, C.; Ajitanand, N. N.

2016-02-04

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured φ meson production and its nuclear modification in asymmetric Cu + Au heavy-ion collisions at √ sNN = 200 GeV at both forward Cu-going direction (1.2 < y < 2.2) and backward Au-going direction (-2.2 < y < -1.2) rapidities. The measurements are performed via the dimuon decay channel and reported as a function of the number of participating nucleons, rapidity, and transverse momentum. In the most central events, 0%–20% centrality, the φ meson yield integrated over 1 < p T < 5 GeV/c prefers a smaller value, whichmore » means a larger nuclear modification, in the Cu-going direction compared to the Au-going direction. Finally and additionally, the nuclear-modification factor in Cu + Au collisions averaged over all centrality is measured to be similar to the previous PHENIX result in d + Au collisions for these rapidities.« less

A colorimetric assay for measuring iodide using Au@Ag core-shell nanoparticles coupled with Cu(2+).

PubMed

Zeng, Jingbin; Cao, Yingying; Lu, Chun-Hua; Wang, Xu-Dong; Wang, Qianru; Wen, Cong-Ying; Qu, Jian-Bo; Yuan, Cunguang; Yan, Zi-Feng; Chen, Xi

2015-09-03

Au@Ag core-shell nanoparticles (NPs) were synthesized and coupled with copper ion (Cu(2+)) for the colorimetric sensing of iodide ion (I(-)). This assay relies on the fact that the absorption spectra and the color of metallic core-shell NPs are sensitive to their chemical ingredient and dimensional core-to-shell ratio. When I(-) was added to the Au@Ag core-shell NPs-Cu(2+) system/solution, Cu(2+) can oxidize I(-) into iodine (I2), which can further oxidize silver shells to form silver iodide (AgI). The generated Au@AgI core-shell NPs led to color changes from yellow to purple, which was utilized for the colorimetric sensing of I(-). The assay only took 10 min with a lowest detectable concentration of 0.5 μM, and it exhibited excellent selectivity for I(-) over other common anions tested. Furthermore, Au@Ag core-shell NPs-Cu(2+) was embedded into agarose gels as inexpensive and portable "test strips", which were successfully used for the semi-quantitation of I(-) in dried kelps. Copyright © 2015 Elsevier B.V. All rights reserved.

Reliability Assessment and Activation Energy Study of Au and Pd-Coated Cu Wires Post High Temperature Aging in Nanoscale Semiconductor Packaging.

PubMed

Gan, C L; Hashim, U

2013-06-01

Wearout reliability and high temperature storage life (HTSL) activation energy of Au and Pd-coated Cu (PdCu) ball bonds are useful technical information for Cu wire deployment in nanoscale semiconductor device packaging. This paper discusses the influence of wire type on the wearout reliability performance of Au and PdCu wire used in fine pitch BGA package after HTSL stress at various aging temperatures. Failure analysis has been conducted to identify the failure mechanism after HTSL wearout conditions for Au and PdCu ball bonds. Apparent activation energies (Eaa) of both wire types are investigated after HTSL test at 150 °C, 175 °C and 200 °C aging temperatures. Arrhenius plot has been plotted for each ball bond types and the calculated Eaa of PdCu ball bond is 0.85 eV and 1.10 eV for Au ball bond in 110 nm semiconductor device. Obviously Au ball bond is identified with faster IMC formation rate with IMC Kirkendall voiding while PdCu wire exhibits equivalent wearout and or better wearout reliability margin compare to conventional Au wirebond. Lognormal plots have been established and its mean to failure (t 50 ) have been discussed in this paper.

System size and energy dependence of jet-induced hadron pair correlation shapes in Cu+Cu and Au+Au collisions at square root sNN=200 and 62.4 GeV.

PubMed

Adare, A; Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Al-Bataineh, H; Alexander, J; Al-Jamel, A; Aoki, K; Aphecetche, L; Armendariz, R; Aronson, S H; Asai, J; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Baksay, G; Baksay, L; 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; Bickley, A A; 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, B S; Chang, W C; Charvet, J-L; Chernichenko, S; Chiba, J; Chi, C Y; Chiu, M; Choi, I J; Choudhury, R K; Chujo, T; Chung, P; Churyn, A; Cianciolo, V; Cleven, C R; Cobigo, Y; Cole, B A; Comets, M P; Constantin, P; Csanád, M; Csörgo, T; Cussonneau, J P; Dahms, T; Das, K; David, G; Deák, F; Deaton, M B; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Dion, A; Donadelli, M; Drachenberg, J L; Drapier, O; Drees, A; Dubey, A K; Durum, A; Dutta, D; Dzhordzhadze, V; Efremenko, Y V; Egdemir, J; Ellinghaus, F; Emam, W S; Enokizono, A; En'yo, H; Espagnon, B; Esumi, S; Eyser, K O; Fields, D E; Finck, C; Finger, M; Finger, M; Fleuret, F; Fokin, S L; Forestier, B; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fung, S-Y; Fusayasu, T; Gadrat, S; Garishvili, I; Gastineau, F; Germain, M; Glenn, A; Gong, H; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, M; Gunji, T; Gustafsson, H-A; Hachiya, T; Hadj Henni, A; Haegemann, C; Haggerty, J S; Hagiwara, M N; Hamagaki, H; Han, R; Hansen, A G; Harada, H; Hartouni, E P; Haruna, K; Harvey, M; Haslum, E; Hasuko, K; Hayano, R; Heffner, M; Hemmick, T K; Hester, T; Heuser, J M; He, X; Hidas, P; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Holmes, M; Holzmann, W; Homma, K; Hong, B; Hoover, A; Horaguchi, T; Hornback, D; Hur, M G; Ichihara, T; Ikonnikov, V V; Imai, K; Inaba, M; Inoue, Y; 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; Kamin, J; Kaneta, M; Kang, J H; Kanou, H; Katou, K; Kawabata, T; Kawagishi, T; Kawall, D; Kazantsev, A V; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, E; Kim, G-B; Kim, H J; Kim, Y-S; Kinney, E; Kiss, A; Kistenev, E; Kiyomichi, A; Klay, J; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Kohara, R; Komkov, B; Konno, M; Kotchetkov, D; Kozlov, A; Král, A; Kravitz, A; Kroon, P J; Kubart, J; Kuberg, C H; Kunde, G J; Kurihara, N; Kurita, K; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y-S; Lajoie, J G; Lebedev, A; Le Bornec, Y; Leckey, S; Lee, D M; Lee, M K; Lee, T; Leitch, M J; Leite, M A L; Lenzi, B; Lim, H; Liska, T; Litvinenko, A; Liu, M X; Li, X; Li, X H; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Malakhov, A; Malik, M D; Manko, V I; Mao, Y; Martinez, G; Masek, L; Masui, H; Matathias, F; Matsumoto, T; McCain, M C; McCumber, M; McGaughey, P L; Miake, Y; Mikes, P; Miki, K; Miller, T E; Milov, A; Mioduszewski, S; Mishra, G C; Mishra, M; Mitchell, J T; Mitrovski, M; Mohanty, A K; Morreale, A; Morrison, D P; Moss, J M; Moukhanova, T V; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagata, Y; Nagle, J L; Naglis, M; Nakagawa, I; Nakamiya, Y; Nakamura, T; Nakano, K; Newby, J; Nguyen, M; Norman, B E; Nyanin, A S; Nystrand, J; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, H; Okada, K; Oka, M; Omiwade, O O; Oskarsson, A; Otterlund, I; Ouchida, M; Oyama, K; Ozawa, K; Pak, R; 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; Qualls, J M; Qu, H; Rak, J; Rakotozafindrabe, A; Ravinovich, I; Read, K F; Rembeczki, S; 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; Sakata, H; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Seele, J; Seidl, R; Semenov, V; Seto, R; Sharma, D; Shea, T K; Shein, I; Shevel, A; Shibata, T-A; Shigaki, K; Shimomura, M; Shohjoh, T; Shoji, K; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, C P; Singh, V; Skutnik, S; Slunecka, M; 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; Toia, A; Tojo, J; Tomásek, L; Torii, H; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Tuli, S K; Tydesjö, H; Tyurin, N; Uam, T J; Vale, C; Valle, H; vanHecke, H W; Velkovska, J; Velkovsky, M; Vertesi, R; Veszprémi, V; Vinogradov, A A; Virius, M; Volkov, M A; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, Y; Wessels, J; White, S N; Willis, N; Winter, D; Wohn, F K; Woody, C L; Wysocki, M; Xie, W; Yamaguchi, Y L; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; Young, G R; Younus, I; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zhang, C; Zhou, S; Zimányi, J; Zolin, L; Zong, X

2007-06-08

We present azimuthal angle correlations of intermediate transverse momentum (1-4 GeV/c) hadrons from dijets in Cu+Cu and Au+Au collisions at square root sNN=62.4 and 200 GeV. The away-side dijet induced azimuthal correlation is broadened, non-Gaussian, and peaked away from Delta phi=pi in central and semicentral collisions in all the systems. The broadening and peak location are found to depend upon the number of participants in the collision, but not on the collision energy or beam nuclei. These results are consistent with sound or shock wave models, but pose challenges to Cherenkov gluon radiation models.

Effect of copper phthalocyanine thickness on surface morphology, optical and electrical properties of Au/CuPc/n-Si heterojunction

NASA Astrophysics Data System (ADS)

Reddy, P. R. Sekhar; Janardhanam, V.; Jyothi, I.; Harsha, Cirandur Sri; Reddy, V. Rajagopal; Lee, Sung-Nam; Won, Jonghan; Choi, Chel-Jong

2018-02-01

Effects of the thickness of copper phthalocyanine (CuPc) film (2, 5, 10, 15, 20, 30 and 40 nm) on the surface morphology, optical and electrical properties of Au/CuPc/n-Si heterojunction have been investigated. The optical band gap of CuPc film was increased with increase in the thickness of the CuPc film. The electrical properties of the Au/n-Si Schottky junction and Au/CuPc/n-Si heterojunctions were characterized by current-voltage ( I-V) and capacitance-voltage ( C-V) measurements. The barrier height, ideality factor and series resistance were estimated based on the I-V, Cheung's and Norde's methods. The barrier heights increased with increasing CuPc interlayer thickness up to 15 nm and remained constant for thickness above 20 nm, associated with the incapability of the generated carriers to reach the interface. The discrepancy in the barrier heights obtained from I-V and C-V measurements indicates the presence of barrier inhomogeneity at the interface as evidenced by higher ideality factor values. It can be concluded that the electrical properties of Au/n-Si Schottky junction can be significantly altered with the variation of CuPc thickness as interlayer.

Highly selective and sensitive method for Cu2 + detection based on chiroptical activity of L-Cysteine mediated Au nanorod assemblies

NASA Astrophysics Data System (ADS)

Abbasi, Shahryar; Khani, Hamzeh

2017-11-01

Herein, we demonstrated a simple and efficient method to detect Cu2 + based on amplified optical activity in the chiral nanoassemblies of gold nanorods (Au NRs). L-Cysteine can induce side-by-side or end-to-end assembly of Au NRs with an evident plasmonic circular dichroism (PCD) response due to coupling between surface plasmon resonances (SPR) of Au NRs and the chiral signal of L-Cys. Because of the obvious stronger plasmonic circular dichrosim (CD) response of the side-by-side assembly compared with the end-to-end assemblies, SS assembled Au NRs was selected as a sensitive platform and used for Cu2 + detection. In the presence of Cu2 +, Cu2 + can catalyze O2 oxidation of cysteine to cystine. With an increase in Cu2 + concentration, the L-Cysteine-mediated assembly of Au NRs decreased because of decrease in the free cysteine thiol groups, and the PCD signal decreased. Taking advantage of this method, Cu2 + could be detected in the concentration range of 20 pM-5 nM. Under optimal conditions, the calculated detection limit was found to be 7 pM.

Highly selective and sensitive method for Cu2+ detection based on chiroptical activity of L-Cysteine mediated Au nanorod assemblies.

PubMed

Abbasi, Shahryar; Khani, Hamzeh

2017-11-05

Herein, we demonstrated a simple and efficient method to detect Cu 2+ based on amplified optical activity in the chiral nanoassemblies of gold nanorods (Au NRs). L-Cysteine can induce side-by-side or end-to-end assembly of Au NRs with an evident plasmonic circular dichroism (PCD) response due to coupling between surface plasmon resonances (SPR) of Au NRs and the chiral signal of L-Cys. Because of the obvious stronger plasmonic circular dichrosim (CD) response of the side-by-side assembly compared with the end-to-end assemblies, SS assembled Au NRs was selected as a sensitive platform and used for Cu 2+ detection. In the presence of Cu 2+ , Cu 2+ can catalyze O 2 oxidation of cysteine to cystine. With an increase in Cu 2+ concentration, the L-Cysteine-mediated assembly of Au NRs decreased because of decrease in the free cysteine thiol groups, and the PCD signal decreased. Taking advantage of this method, Cu 2+ could be detected in the concentration range of 20pM-5nM. Under optimal conditions, the calculated detection limit was found to be 7pM. Copyright © 2017 Elsevier B.V. All rights reserved.

Measurements of directed, elliptic, and triangular flow in Cu + Au collisions at √{sNN}=200 GeV

NASA Astrophysics Data System (ADS)

Adare, A.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Aoki, K.; Apadula, N.; Asano, H.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butsyk, S.; Campbell, S.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Christiansen, P.; Chujo, T.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Ding, L.; Dion, A.; Diss, P. B.; Do, J. H.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Durham, J. M.; Durum, A.; 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.; Gu, Y.; Gunji, T.; Guragain, H.; 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.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Ikeda, Y.; Imai, K.; Imazu, Y.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ivanishchev, D.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapustinsky, J.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kijima, K. M.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kimelman, B.; Kistenev, E.; Kitamura, R.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kofarago, M.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, G. H.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Leitch, M. J.; Leitgab, M.; Lewis, B.; Li, X.; Lim, S. H.; Liu, M. X.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Maruyama, T.; 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.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, T.; Morrison, D. P.; Moskowitz, M.; 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.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Peng, J.-C.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; 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.; Riveli, N.; Roach, D.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Snowball, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takahara, A.; Taketani, A.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, R.; Towell, R. S.; Tserruya, I.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; White, A. S.; Wolin, S.; Woody, C. L.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yanovich, A.; 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

2016-11-01

Measurements of anisotropic flow Fourier coefficients (vn) for inclusive charged particles and identified hadrons π±, K±, p , and p ¯ produced at midrapidity in Cu +Au collisions at √{s NN}=200 GeV are presented. The data were collected in 2012 by the PHENIX experiment at the Relativistic Heavy-Ion Collider (RHIC). The particle azimuthal distributions with respect to different-order symmetry planes Ψn, for n =1 , 2, and 3 are studied as a function of transverse momentum pT over a broad range of collision centralities. Mass ordering, as expected from hydrodynamic flow, is observed for all three harmonics. The charged-particle results are compared with hydrodynamical and transport model calculations. We also compare these Cu +Au results with those in Cu +Cu and Au +Au collisions at the same √{sNN} and find that the v2 and v3, as a function of transverse momentum, follow a common scaling with 1 /(ɛnNpart1 /3) .

ϕ meson production in the forward/backward rapidity region in Cu + Au collisions at √{sNN}=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.; Andrews, K. R.; Angerami, A.; Aoki, K.; Apadula, N.; Appelt, E.; Aramaki, Y.; Armendariz, R.; Asano, H.; Aschenauer, E. C.; Atomssa, E. T.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bassalleck, B.; Basye, A. T.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belmont, R.; Ben-Benjamin, J.; Bennett, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Broxmeyer, D.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Bunce, G.; 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.; Conesa Del Valle, Z.; Connors, M.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Dairaku, S.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Dayananda, M. K.; 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.; Efremenko, Y. V.; Engelmore, T.; Enokizono, A.; En'yo, H.; 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.; Gu, Y.; Gunji, T.; Guo, L.; Guragain, H.; Gustafsson, H.-Å.; Hachiya, T.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamblen, J.; Hamilton, H. F.; Han, R.; Han, S. Y.; Hanks, J.; Harper, C.; 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.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hori, Y.; Hornback, D.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Ichimiya, R.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imazu, Y.; Inaba, M.; Iordanova, A.; Isenhower, D.; Ishihara, M.; Isinhue, A.; Issah, M.; Ivanishchev, D.; Iwanaga, Y.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Jia, J.; Jiang, X.; John, D.; Johnson, B. M.; Jones, T.; 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.; Khandai, P. K.; Khanzadeev, A.; Kijima, K. M.; Kim, B. I.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, G. W.; 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.; Kochenda, L.; Kofarago, M.; Komkov, B.; Konno, M.; 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, D. M.; Lee, G. H.; 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, H.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Manion, A.; Manko, V. I.; Mannel, E.; Mao, Y.; Maruyama, T.; Masui, H.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Means, N.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Miki, K.; 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.; Morino, Y.; Morreale, A.; Morrison, D. P.; Moskowitz, M.; Motschwiller, S.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagamiya, S.; Nagashima, K.; Nagle, J. L.; Naglis, M.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Newby, J.; Nguyen, M.; Nihashi, M.; Niida, T.; Nishimura, S.; Nouicer, R.; Novák, T.; Novitzky, N.; Nyanin, A. S.; Oakley, C.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Oka, M.; 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.; Reygers, K.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Rinn, T.; Riveli, N.; Roach, D.; Roche, G.; Rolnick, S. D.; Rosati, M.; Rosendahl, S. S. E.; Rowan, Z.; Rubin, J. G.; Ryu, M. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sano, S.; Sarsour, M.; Sato, S.; Sato, T.; Savastio, M.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shim, H. H.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Skolnik, M.; Slunečka, M.; Snowball, M.; Sodre, T.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Takagui, E. M.; Takahara, A.; Taketani, A.; Tanabe, R.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tennant, E.; Themann, H.; Thomas, D.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Togawa, M.; Tomášek, L.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, R.; Towell, R. S.; Tserruya, I.; Tsuchimoto, Y.; Utsunomiya, K.; 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.; Wessels, J.; Whitaker, S.; White, A. S.; White, S. N.; Winter, D.; Wolin, S.; Woody, C. L.; Wright, R. M.; Wysocki, M.; Xia, B.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yang, R.; Yanovich, A.; Ying, J.; Yokkaichi, S.; Yoo, J. H.; Yoo, J. S.; Yoon, I.; You, Z.; Young, G. R.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zhou, S.; Zou, L.; Phenix Collaboration

2016-02-01

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured ϕ meson production and its nuclear modification in asymmetric Cu +Au heavy-ion collisions at √{sNN}=200 GeV at both forward Cu-going direction (1.2 Au-going direction (-2.2 Cu-going direction compared to the Au-going direction. Additionally, the nuclear-modification factor in Cu +Au collisions averaged over all centrality is measured to be similar to the previous PHENIX result in d +Au collisions for these rapidities.

A synthesis of mineralization styles and geodynamic settings of the Paleozoic and Mesozoic metallic ore deposits in the Altay Mountains, NW China

NASA Astrophysics Data System (ADS)

Yang, Fuquan; Geng, Xinxia; Wang, Rui; Zhang, Zhixin; Guo, Xuji

2018-06-01

The Altay Mountains within the Xinjiang region of northwestern China hosts major metallic ore deposits. Here we review the geological characteristics, metallogenic features and tectonic settings of these deposits. The metallic ore deposits in the Altay Mountains occur mainly within four regions: North Altay, Central Altay, South Altay and Erqis. We recognize seven types of metallic ore deposits in the Altay Mountains: VMS, submarine volcanogenic iron, magmatic, skarn, pegmatite, hydrothermal vein (Cu-Zn, Fe) and orogenic gold. Among these types, the VMS, pegmatite, orogenic gold and skarn deposits are the most common. Most of the rare metal pegmatite deposits are distributed in Central Altay, with only a few in South Altay. The VMS, submarine volcanogenic type iron and skarn-type deposits are distributed in South Altay, whereas the orogenic-type gold deposits are distributed in the Erqis Fault belt. The hydrothermal vein-type deposits occur in the Erqis Fault belt and Chonghu'er Basin in South Altay. Magmatic-type deposits are mostly in the Erqis Fault belt and Central Altay. Based on isotopic age data, the VMS, submarine volcanogenic-type Fe and skarn-type Cu, Pb, Zn, Fe mineralization occurred during Early-Middle Devonian (∼410-377 Ma), orogenic-type Au, magmatic-type Cu-Ni, and a small number of skarn-type Fe, hydrothermal vein-type Cu-Zn, pegmatite-type rare-metal deposits in Early-Middle Permian (293-261 Ma), pegmatite-type rare-metal deposits, few skarn-type Fe deposit in Early-Middle Triassic (248-232 Ma), and dominantly represented by pegmatite-type rare-metal deposits in Late Triassic-Early Jurassic (223-180 Ma). The metallic ore deposits in the Altay Mountains formed in various tectonic settings, such as the Early-Middle Devonian continental arc and oceanic island arc, Early-Middle Permian post-collisional extensional setting, and Triassic-Early Jurassic intracontinental setting.

Measurement of KS0 and K*0 in p +p ,d +Au , and Cu + Cu collisions at √{sNN}=200 GeV

NASA Astrophysics Data System (ADS)

Adare, A.; Afanasiev, S.; Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Al-Bataineh, H.; Alexander, J.; Alfred, M.; Angerami, A.; Aoki, K.; Apadula, N.; Aphecetche, L.; Aramaki, Y.; Armendariz, R.; Aronson, S. H.; Asai, J.; Asano, H.; Atomssa, E. T.; Averbeck, R.; Awes, T. C.; Azmoun, B.; Babintsev, V.; Bai, M.; Baksay, G.; Baksay, L.; Baldisseri, A.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Barnes, P. D.; Bassalleck, B.; Basye, A. T.; Bathe, S.; Batsouli, S.; Baublis, V.; Baumann, C.; Bazilevsky, A.; Beaumier, M.; Beckman, S.; Belikov, S.; Belmont, R.; Bennett, R.; Berdnikov, A.; Berdnikov, Y.; Bhom, J. H.; Bickley, A. A.; Black, D.; Blau, D. S.; Boissevain, J. G.; Bok, J. S.; Borel, H.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Bunce, G.; Butsyk, S.; Campbell, S.; Caringi, A.; Chang, B. S.; Charvet, J.-L.; Chen, C.-H.; Chernichenko, S.; Chi, C. Y.; Chiba, J.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choudhury, R. K.; Christiansen, P.; Chujo, T.; Chung, P.; Churyn, A.; Chvala, O.; Cianciolo, V.; Citron, Z.; Cleven, C. R.; Cole, B. A.; Comets, M. P.; Conesa Del Valle, Z.; Connors, M.; Constantin, P.; Csanád, M.; Csörgő, T.; Dahms, T.; Dairaku, S.; Danchev, I.; Das, K.; Datta, A.; Daugherity, M. S.; David, G.; Dayananda, M. K.; Deaton, M. B.; Deblasio, K.; Dehmelt, K.; Delagrange, H.; Denisov, A.; D'Enterria, D.; Deshpande, A.; Desmond, E. J.; Dharmawardane, K. V.; Dietzsch, O.; Ding, L.; Dion, A.; Do, J. H.; Donadelli, M.; Drapier, O.; Drees, A.; Drees, K. A.; Dubey, A. K.; Durham, J. M.; Durum, A.; Dutta, D.; Dzhordzhadze, V.; D'Orazio, L.; Edwards, S.; Efremenko, Y. V.; Egdemir, J.; Ellinghaus, F.; Emam, W. S.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Fraenkel, Z.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fujiwara, K.; Fukao, Y.; Fusayasu, T.; Gadrat, S.; Gal, C.; Gallus, P.; Garg, P.; Garishvili, I.; Ge, H.; Giordano, F.; Glenn, A.; Gong, H.; Gonin, M.; Gosset, J.; Goto, Y.; Granier de Cassagnac, R.; Grau, N.; Greene, S. V.; Grim, G.; Grosse Perdekamp, M.; Gu, Y.; Gunji, T.; Guragain, H.; Gustafsson, H.-Å.; Hachiya, T.; Hadj Henni, A.; Haegemann, C.; Haggerty, J. S.; Hahn, K. I.; Hamagaki, H.; Hamblen, J.; Han, R.; Han, S. Y.; Hanks, J.; Harada, H.; Hartouni, E. P.; Haruna, K.; Hasegawa, S.; Haslum, E.; Hayano, R.; He, X.; Heffner, M.; Hemmick, T. K.; Hester, T.; Hiejima, H.; Hill, J. C.; Hobbs, R.; Hohlmann, M.; Hollis, R. S.; Holzmann, W.; Homma, K.; Hong, B.; Horaguchi, T.; Hornback, D.; Hoshino, T.; Huang, S.; Ichihara, T.; Ichimiya, R.; Iinuma, H.; Ikeda, Y.; Imai, K.; Imazu, Y.; Inaba, M.; Inoue, Y.; Iordanova, A.; Isenhower, D.; Isenhower, L.; Ishihara, M.; Isobe, T.; Issah, M.; Isupov, A.; Ivanischev, D.; Ivanishchev, D.; Iwanaga, Y.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Jia, J.; Jiang, X.; Jin, J.; Jinnouchi, O.; Johnson, B. M.; Jones, T.; Joo, E.; Joo, K. S.; Jouan, D.; Jumper, D. S.; Kajihara, F.; Kametani, S.; Kamihara, N.; Kamin, J.; Kaneta, M.; Kang, J. H.; Kang, J. S.; Kanou, H.; Kapustinsky, J.; Karatsu, K.; Kasai, M.; Kawall, D.; Kawashima, M.; Kazantsev, A. V.; Kempel, T.; Key, J. A.; Khachatryan, V.; Khanzadeev, A.; Kihara, K.; Kijima, K. M.; Kikuchi, J.; Kim, A.; Kim, B. I.; Kim, C.; Kim, D. H.; Kim, D. J.; Kim, E.; Kim, E.-J.; Kim, H.-J.; Kim, M.; Kim, Y.-J.; Kim, Y. K.; Kinney, E.; Kiss, Á.; Kistenev, E.; Kiyomichi, A.; Klatsky, J.; Klay, J.; Klein-Boesing, C.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kochenda, L.; Kochetkov, V.; Kofarago, M.; Komkov, B.; Konno, M.; Koster, J.; Kotchetkov, D.; Kotov, D.; Kozlov, A.; Král, A.; Kravitz, A.; Kubart, J.; Kunde, G. J.; Kurihara, N.; Kurita, K.; Kurosawa, M.; Kweon, M. J.; Kwon, Y.; Kyle, G. S.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lebedev, A.; Lee, D. M.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, M. K.; Lee, S. H.; Lee, T.; Leitch, M. J.; Leite, M. A. L.; Leitgab, M.; Lenzi, B.; Li, X.; Lichtenwalner, P.; Liebing, P.; Lim, S. H.; Linden Levy, L. A.; Liška, T.; Litvinenko, A.; Liu, H.; Liu, M. X.; Love, B.; Lynch, D.; Maguire, C. F.; Makdisi, Y. I.; Makek, M.; Malakhov, A.; Malik, M. D.; Manion, A.; Manko, V. I.; Mannel, E.; Mao, Y.; Mašek, L.; Masui, H.; Matathias, F.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Means, N.; Meles, A.; Mendoza, M.; Meredith, B.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Mikeš, P.; Miki, K.; Miller, A. J.; Miller, T. E.; Milov, A.; Mioduszewski, S.; Mishra, D. K.; Mishra, M.; Mitchell, J. T.; Mitrovski, M.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Montuenga, P.; Moon, H. J.; Moon, T.; Morino, Y.; Morreale, A.; Morrison, D. P.; Moukhanova, T. V.; Mukhopadhyay, D.; Murakami, T.; Murata, J.; Mwai, A.; Nagamiya, S.; Nagata, Y.; Nagle, J. L.; Naglis, M.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nam, S.; Nattrass, C.; Netrakanti, P. K.; Newby, J.; Nguyen, M.; Nihashi, M.; Niida, T.; Norman, B. E.; Nouicer, R.; Novitzky, N.; Nyanin, A. S.; Oakley, C.; O'Brien, E.; Oda, S. X.; Ogilvie, C. A.; Ohnishi, H.; Oka, M.; Okada, K.; Omiwade, O. O.; Onuki, Y.; Orjuela Koop, J. D.; Oskarsson, A.; Ouchida, M.; Ozaki, H.; Ozawa, K.; Pak, R.; Pal, D.; Palounek, A. P. T.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J.; Park, S.; Park, S. K.; Park, W. J.; Pate, S. F.; Patel, L.; Patel, M.; Pei, H.; Peng, J.-C.; Pereira, H.; Perepelitsa, D. V.; Perera, G. D. N.; Peresedov, V.; Peressounko, D. Yu.; Perry, J.; Petti, R.; Pinkenburg, C.; Pinson, R.; Pisani, R. P.; Proissl, M.; Purschke, M. L.; Purwar, A. K.; Qu, H.; Rak, J.; Rakotozafindrabe, A.; Ravinovich, I.; Read, K. F.; Rembeczki, S.; Reuter, M.; Reygers, K.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Riveli, N.; Roach, D.; Roche, G.; Rolnick, S. D.; Romana, A.; Rosati, M.; Rosen, C. A.; Rosendahl, S. S. E.; Rosnet, P.; Rowan, Z.; Rubin, J. G.; Rukoyatkin, P.; Ružička, P.; Rykov, V. L.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sakai, S.; Sakashita, K.; Sakata, H.; Sako, H.; Samsonov, V.; Sano, S.; Sarsour, M.; Sato, S.; Sato, T.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Semenov, V.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shein, I.; Shevel, A.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Silvestre, C.; Sim, K. S.; Singh, B. K.; Singh, C. P.; Singh, V.; Skutnik, S.; Slunečka, 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.; Suire, C.; Sukhanov, A.; Sumita, T.; Sun, J.; Sziklai, J.; Tabaru, T.; Takagi, S.; Takagui, E. M.; Takahara, A.; Taketani, A.; Tanabe, R.; Tanaka, Y.; Taneja, S.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarján, P.; Themann, H.; Thomas, D.; Thomas, T. L.; Timilsina, A.; Todoroki, T.; Togawa, M.; Toia, A.; Tojo, J.; Tomášek, L.; Tomášek, M.; Torii, H.; Towell, M.; Towell, R.; Towell, R. S.; Tram, V.-N.; Tserruya, I.; Tsuchimoto, Y.; Vale, C.; Valle, H.; van Hecke, H. W.; Vargyas, M.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Vinogradov, A. A.; Virius, M.; Vrba, V.; Vznuzdaev, E.; Wagner, M.; Walker, D.; Wang, X. R.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Wei, R.; Wessels, J.; Whitaker, S.; White, S. N.; Winter, D.; Wolin, S.; Woody, C. L.; Wright, R. M.; Wysocki, M.; Xia, B.; Xie, W.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamaura, K.; Yang, R.; Yanovich, A.; Yasin, Z.; Ying, J.; Yokkaichi, S.; Yoon, I.; You, Z.; Young, G. R.; Younus, I.; Yushmanov, I. E.; Zajc, W. A.; Zaudtke, O.; Zelenski, A.; Zhang, C.; Zhou, S.; Zimányi, J.; Zolin, L.; Phenix Collaboration

2014-11-01

The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of KS0 and K*0 meson production at midrapidity in p +p ,d +Au , and Cu +Cu collisions at √{s NN}=200 GeV. The KS0 and K*0 mesons are reconstructed via their KS0→π0(→γ γ ) π0(→γ γ ) and K*0→K±π∓ decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of KS0 and K*0 mesons in d +Au and Cu +Cu collisions at different centralities. In the d +Au collisions, the nuclear modification factor of KS0 and K*0 mesons is almost constant as a function of transverse momentum and is consistent with unity, showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu +Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p +p yield scaled by the number of binary nucleon-nucleon collisions in the Cu +Cu system. In the pT range 2 - 5 GeV /c , the strange mesons (KS0,K*0) similarly to the ϕ meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (π0) and the nonsuppressed baryons (p ,p ¯). At higher transverse momentum, pT>5 GeV /c , production of all particles is similarly suppressed by a factor of ≈2 .

B -meson production at forward and backward rapidity in p + p and Cu + Au collisions at s N N = 200 GeV

DOE PAGES

Aidala, C.; Ajitanand, N. N.; Akiba, Y.; ...

2017-12-04

The fraction of J/Ψ mesons which come from B-meson decay, F B→J/Ψ, is measured in this paper for J/Ψ rapidity 1.2 < |y| < 2.2 and p T > 0 in p + p and Cu+Au collisions at √ sNN = 200 GeV with the PHENIX detector. The extracted fraction is F B→J/Ψ = 0.025 ± 0.006 (stat) ± 0.010(syst) for p + p collisions. For Cu+Au collisions, F B→J/Ψ is 0.094 ± 0.028 (stat) ± 0.037(syst) in the Au-going direction (-2.2 < y < -1.2) and 0.089 ± 0.026(stat) ± 0.040(syst) in the Cu-going direction (1.2 < y CuAu, of B mesons in Cu+Au collisions is consistent with binary scaling of measured yields in p + p at both forward and backward rapidity.« less

B -meson production at forward and backward rapidity in p + p and Cu + Au collisions at s N N = 200 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aidala, C.; Ajitanand, N. N.; Akiba, Y.

The fraction of J/Ψ mesons which come from B-meson decay, F B→J/Ψ, is measured in this paper for J/Ψ rapidity 1.2 < |y| < 2.2 and p T > 0 in p + p and Cu+Au collisions at √ sNN = 200 GeV with the PHENIX detector. The extracted fraction is F B→J/Ψ = 0.025 ± 0.006 (stat) ± 0.010(syst) for p + p collisions. For Cu+Au collisions, F B→J/Ψ is 0.094 ± 0.028 (stat) ± 0.037(syst) in the Au-going direction (-2.2 < y < -1.2) and 0.089 ± 0.026(stat) ± 0.040(syst) in the Cu-going direction (1.2 < y CuAu, of B mesons in Cu+Au collisions is consistent with binary scaling of measured yields in p + p at both forward and backward rapidity.« less

Intermixing behaviors of PCBM with CuPc on Au(1 1 1) surface

NASA Astrophysics Data System (ADS)

Masui, Akane; Sakaue, Hiroyuki; Takahagi, Takayuki; Suzuki, Hitoshi

2016-09-01

The behavior of phenyl-C61-butyric acid methyl ester (PCBM) and copper-phthalocyanine (CuPc) on a Au(1 1 1) surface was investigated using scanning tunneling microscopy (STM). When CuPc was deposited in addition to PCBM it entered and disturbed the regularly spaced double row superstructure of the PCBM molecules. PCBM intermixed with CuPc to form a new square shaped superstructure that consisted of six to eight PCBM molecules with a CuPc molecule in its center. The intermixing of these materials that was observed indicated that they possessed an attractive interaction.

A theoretical investigation on Cu/Ag/Au bonding in XH2P⋯MY(X = H, CH3, F, CN, NO2; M = Cu, Ag, Au; Y = F, Cl, Br, I) complexes

NASA Astrophysics Data System (ADS)

Wang, Zhaoxu; Liu, Yi; Zheng, Baishu; Zhou, Fengxiang; Jiao, Yinchun; Liu, Yuan; Ding, XunLei; Lu, Tian

2018-05-01

Intermolecular interaction of XH2P...MY (X = H, CH3, F, CN, NO2; M = Cu, Ag, Au; Y = F, Cl, Br, I) complexes was investigated by means of an ab initio method. The molecular interaction energies are in the order Ag < Cu < Au and increased with the decrease of RP...M. Interaction energies are strengthened when electron-donating substituents X connected to XH2P, while electron-withdrawing substituents produce the opposite effect. The strongest P...M bond was found in CH3H2P...AuF with -70.95 kcal/mol, while the weakest one was found in NO2H2P...AgI with -20.45 kcal/mol. The three-center/four-electron (3c/4e) resonance-type of P:-M-:Y hyperbond was recognized by the natural resonance theory and the natural bond orbital analysis. The competition of P:M-Y ↔ P-M:Y resonance structures mainly arises from hyperconjugation interactions; the bond order of bP-M and bM-Y is in line with the conservation of the idealized relationship bP-M + bM-Y ≈ 1. In all MF-containing complexes, P-M:F resonance accounted for a larger proportion which leads to the covalent characters for partial ionicity of MF. The interaction energies of these Cu/Ag/Au complexes are basically above the characteristic values of the halogen-bond complexes and close to the observed strong hydrogen bonds in ionic hydrogen-bonded species.

Influence of Cu, Au and Ag on structural and surface properties of bioactive coatings based on titanium.

PubMed

Wojcieszak, D; Mazur, M; Kalisz, M; Grobelny, M

2017-02-01

In this work influence of copper, silver and gold additives on structural and surface properties of biologically active thin films based on titanium have been described. Coatings were prepared by magnetron sputtering method. During each process metallic discs (targets) - Ti and the additive (Cu, Ag or Au) were co-sputtered in argon atmosphere. Structural investigation of as-deposited coatings was performed with the aid of XRD and SEM/EDS method. It was found that all prepared thin films were homogenous. Addition of Cu, Ag and Au resulted in nanocrystalline structure. Moreover, influence of these additives on hardness and antibacterial activity of titanium coatings was also studied. Ti-Cu, Ti-Ag and Ti-Au films had lower hardness as-compared to Ti. According to AAS results the difference of their activity was related to the ion migration process. It was found that Ti-Ag and Ti-Au coatings had biocidal effect related to direct contact of their surface with microorganisms. In the case of Ti-Cu antimicrobial activity had direct and indirect nature due to efficient ion migration process from the film surface to the surrounding environment. Functional features of coatings such as wettability and corrosion resistance were also examined and included in the comprehensive analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Electronic structures and nonlinear optical properties of trinuclear transition metal clusters M-(mu-S)-M' (M = Mo, W; M' = Cu, Ag, Au).

PubMed

Chen, Xihua; Wu, Kechen; Snijders, Jaap G; Lin, Chensheng

2003-01-27

A series of trinuclear metal clusters MS4(M'PPh3)2(M'PPh3) (M = Mo, W; M' = Cu, Ag, Au) have been studied using the density functional theory (DFT) method. The static polarizabilities and hyperpolarizabilities of the model clusters have been calculated using the finite-field (F-F) method. The model clusters, divided into two groups, are alike in the structure of two fragments of rhombic units M-(mu-S)2-M' (M = Mo, W; M' = Cu, Ag, Au), perpendicular to each other, which are joined by sharing the bridge metal M. It is the charge transfer from one of these moieties to the other in these characteristic sulfido-transitional metal cores that is responsible for the polarizabilities and hyperpolarizabilities. This kind of electronic delocalization, different from that of the planar pi-system, is interesting and warrants further investigation. The structural effects on properties are important. In these models, considerable third-order nonlinearities are exhibited. The element substitution effect of Mo and W is weak, while that of Cu and Ag is relatively substantial. An overall order is gamma xxxx(Mo-Ag) > gamma xxxx(W-Ag) > gamma xxxx(Mo-Au) > gamma xxxx(W-Au) > gamma xxxx (Mo-Cu) > gamma xxxx(W-Cu) and gamma av(Mo-Ag) approximately gamma av(W-Ag) > gamma av(Mo-Au) approximately gamma av(W-Au) approximately gamma av (Mo-Cu) approximately gamma av(W-Cu).

Slab melting and the origin of gold in Au and Au-Cu deposits: geochemical clues from recent adakites.

NASA Astrophysics Data System (ADS)

Polve, M.; Maury, R.; Joron, J. L.

2003-04-01

Understanding the genetic processes responsible for the common occurrence of Au and Au-Cu deposits in subduction environments is a fairly "hot" question nowadays, as it is clear that most subduction-related magmatic rocks are barren. Studies of space and time relationships between magmatic intrusions, hydrothermal episodes and Au deposits have shown that, very often, Au deposits are associated with adakitic intrusions (Thieblemont et al, 1997, Sajona and Maury, 1998). Adakites are here understood as being generated by melting of the subducting oceanic crust. This study aims to check wether or not magmas derived from melted oceanic crust do contain significantly more Au than regular calc-alkaline magmas by measuring directly Au concentrations in fresh (and barren) adakites and equivalent calc-alkaline andesites. There is a lack of reliable data on Au content in unaltered adakites and andesites, because Au analyses are generally done on hydrothermalized rocks in connection with Au deposits and also because old measurements may give overestimated Au contents, due to technical limitations. Therefore we compiled recent literature data on gold contents of fresh calc-alkaline rocks, and measured Au on a selection of 40 well studied and dated adakites from different localities (Philippines, Baja California). Analyses have been performed either by INAA or by ICP-MS after Au extraction with aqua regia, following the method described by Terashima (1988). Preliminary results show that, for equivalent Si02 contents, adakites are systematically enriched in Au compared to regular dacites, even if regional trends also exist. Moreover, Au seems to behave as an incompatible element in adakitic magmas, whereas in calc-alkaline dacites it is controlled by sulfide crystallization. Our data suggest that, not excluding any other processes related to the hydrothermal phase in the deposit generation, adakites may indeed represent the source of Au, a possible explanation for the adakite-Au

Measurements of directed, elliptic, and triangular flow in Cu + Au collisions at s NN = 200 GeV

DOE PAGES

Adare, A.; Aidala, C.; Ajitanand, N. N.; ...

2016-11-28

In this paper, measurements of anisotropic flow Fourier coefficients (v n) for inclusive charged particles and identified hadrons π ± ,K ±, p, andmore » $$\\overline{p}$$ produced at midrapidity in Cu + Au collisions at √sNN = 200 GeV are presented. The data were collected in 2012 by the PHENIX experiment at the Relativistic Heavy-Ion Collider (RHIC). The particle azimuthal distributions with respect to different-order symmetry planes Ψ n ,for n = 1, 2, and 3 are studied as a function of transverse momentum p T over a broad range of collision centralities. Mass ordering, as expected from hydrodynamic flow, is observed for all three harmonics. The charged-particle results are compared with hydrodynamical and transport model calculations. In addition, we also compare these Cu + Au results with those in Cu + Cu and Au + Au collisions at the same √sNN and find that the v 2 and v 3, as a function of transverse momentum, follow a common scaling with 1/(ε nN 1/3 part).« less

Photon cross sections in Cu, Pt, and Au at 81 keV

NASA Astrophysics Data System (ADS)

Seetharami Reddy, B.; Ramana Rao, P. V.; Premchand, K.; Parthasaradhi, K.

1987-02-01

Total photon cross sections in Cu, Pt, and Au are measured employing the doublet 79.623- and 80.999-keV γ's of 133Ba. A dilution of the cross section by about 12% is observed at the average energy of the doublet in Au due to K-edge falling in between these two energies. Scofield's theoretical value in this case is seen to be underestimated by about 75% due to the use of different K-edge energies in Au. However, an alternative but customarily followed procedure is to ignore the lower K-edge data of Scofield and extrapolate using upper-edge data which yield a value agreeing satisfactorily with the experimental value at 80.905 keV.

Zinc-doping enhanced cadmium sulfide electrochemiluminescence behavior based on Au-Cu alloy nanocrystals quenching for insulin detection.

PubMed

Zhu, Wenjuan; Wang, Chao; Li, Xiaojian; Khan, Malik Saddam; Sun, Xu; Ma, Hongmin; Fan, Dawei; Wei, Qin

2017-11-15

Novel and sensitive sandwich-type electrochemiluminescence (ECL) immunosensor was fabricated for insulin detection. Au-ZnCd 14 S combined nitrogen doping mesoporous carbons (Au-ZnCd 14 S/NH 2 -NMCs) acted as sensing platform and Au-Cu alloy nanocrystals were employed as labels to quench the ECL of Au-ZnCd 14 S/NH 2 -NMCs. Zinc-doping promoted the ECL behavior of CdS nanocrystals, with the best ECL emission obtained when the molar ratio of Zn/Cd was 1:14. Simultaneously, the modification of gold nanoparticles (Au NPs) and combination with NH 2 -NMC further enhanced the ECL emission of ZnCd 14 S due to its excellent conductivity and large specific surface area, which is desirable for the immunosensor construction. Au-Cu alloy nanocrystals were employed in the ECL system of ZnCd 14 S/K 2 S 2 O 8 triggering ECL quenching effects. The ECL spectra of ZnCd 14 S, acting as the energy donor, exhibited well overlaps with the absorption band of Au-Cu alloy nanocrystals which acted as the energy acceptor, leading to an effective ECL resonance energy transfer (ECL-RET). On the basis of the ECL quenching effects, a sensitive ECL immunosensor for insulin detection was successfully constructed with a linear response range of insulin concentration from 0.1pg/mL to 30ng/mL and the limit of detection was calculated to be 0.03pg/mL (S/N = 3). Copyright © 2017 Elsevier B.V. All rights reserved.

Co-Cu-Au deposits in metasedimentary rocks-A preliminary report

USGS Publications Warehouse

Slack, J.F.; Causey, J.D.; Eppinger, R.G.; Gray, J.E.; Johnson, C.A.; Lund, K.I.; Schulz, K.J.

2010-01-01

A compilation of data on global Co-Cu-Au deposits in metasedimentary rocks refines previous descriptive models for their occurrence and provides important information for mineral resource assessments and exploration programs. This compilation forms the basis for a new classification of such deposits, which is speculative at this early stage of research. As defined herein, the Co-Cu-Au deposits contain 0.1 percent or more by weight of Co in ore or mineralized rock, comprising disseminated to semi-massive Co-bearing sulfide minerals with associated Fe- and Cu-bearing sulfides, and local gold, concentrated predominantly within rift-related, siliciclastic metasedimentary rocks of Proterozoic age. Some deposits have appreciable Ag ? Bi ? W ? Ni ? Y ? rare earth elements ? U. Deposit geometry includes stratabound and stratiform layers, lenses, and veins, and (or) discordant veins and breccias. The geometry of most deposits is controlled by stratigraphic layering, folds, axial-plane cleavage, shear zones, breccias, or faults. Ore minerals are mainly cobaltite, skutterudite, glaucodot, and chalcopyrite, with minor gold, arsenopyrite, pyrite, pyrrhotite, bismuthinite, and bismuth; some deposits have appreciable tetrahedrite, uraninite, monazite, allanite, xenotime, apatite, scheelite, or molybdenite. Magnetite can be abundant in breccias, veins, or stratabound lenses within ore or surrounding country rocks. Common gangue minerals include quartz, biotite, muscovite, K-feldspar, albite, chlorite, and scapolite; many deposits contain minor to major amounts of tourmaline. Altered wall rocks generally have abundant biotite or albite. Mesoproterozoic metasedimentary successions constitute the predominant geologic setting. Felsic and (or) mafic plutons are spatially associated with many deposits and at some localities may be contemporaneous with, and involved in, ore formation. Geoenvironmental data for the Blackbird mining district in central Idaho indicate that weathering of

Reduction of Ag{sup I}, Au{sup III}, Cu{sup II}, and Hg{sup II} by Fe{sup II}/Fe{sup III} hydroxysulfate green rust.

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Loughlin, E. J.; Kelly, S. D.; Kemner, K. M.

Green rusts are mixed Fe{sup II}/Fe{sup III} hydroxides that are found in many suboxic environments where they are believed to play a central role in the biogeochemical cycling of iron. X-ray absorption fine structure analysis of hydroxysulfate green rust suspensions spiked with aqueous solutions of AgCH{sub 3}COO, AuCl{sub n}(OH){sub 4-n}, CuCl{sub 2}, or HgCl{sub 2} showed that Ag{sup I}, Au{sup III}, Cu{sup II}, and Hg{sup II} were readily reduced to Ag{sup 0}, Au{sup 0}, Cu{sup 0}, and Hg{sup 0}. Imaging of the resulting solids from the Ag{sup I}-, Au{sup III}-, and Cu{sup II}-amended green rust suspensions by transmission electron microscopymore » indicated the formation of submicron-sized particles of Ag{sup 0}, Au{sup 0}, and Cu{sup 0}. The facile reduction of Ag{sup I}, Au{sup III}, Cu{sup II}, and Hg{sup II} to Ag{sup 0}, Au{sup 0}, Cu{sup 0}, and Hg{sup 0}, respectively, by green rust suggests that the presence of green rusts in suboxic soils and sediments can have a significant impact on the biogeochemistry of silver, gold, copper, and mercury, particularly with respect to their mobility.« less

B -meson production at forward and backward rapidity in p +p and Cu + Au collisions at √{sN N}=200 GeV

NASA Astrophysics Data System (ADS)

Aidala, C.; Ajitanand, N. N.; Akiba, Y.; Akimoto, R.; Alexander, J.; Alfred, M.; Andrieux, V.; Aoki, K.; Apadula, N.; Asano, H.; Atomssa, E. T.; Awes, T. C.; Ayuso, C.; Azmoun, B.; Babintsev, V.; Bagoly, A.; Bai, M.; Bai, X.; Bandara, N. S.; Bannier, B.; Barish, K. N.; Bathe, S.; Baublis, V.; Baumann, C.; Baumgart, S.; Bazilevsky, A.; Beaumier, M.; Belmont, R.; Berdnikov, A.; Berdnikov, Y.; Black, D.; Blau, D. S.; Boer, M.; Bok, J. S.; Boyle, K.; Brooks, M. L.; Bryslawskyj, J.; Buesching, H.; Bumazhnov, V.; Butler, C.; Butsyk, S.; Campbell, S.; Canoa Roman, V.; Cervantes, R.; Chen, C.-H.; Chi, C. Y.; Chiu, M.; Choi, I. J.; Choi, J. B.; Choi, S.; Christiansen, P.; Chujo, T.; Cianciolo, V.; Citron, Z.; Cole, B. A.; Connors, M.; Cronin, N.; Crossette, N.; Csanád, M.; Csörgő, T.; Danley, T. W.; Datta, A.; Daugherity, M. S.; David, G.; Deblasio, K.; Dehmelt, K.; Denisov, A.; Deshpande, A.; Desmond, E. J.; Ding, L.; Dion, A.; Dixit, D.; Do, J. H.; D'Orazio, L.; Drapier, O.; Drees, A.; Drees, K. A.; Dumancic, M.; Durham, J. M.; Durum, A.; Elder, T.; Engelmore, T.; Enokizono, A.; En'yo, H.; Esumi, S.; Eyser, K. O.; Fadem, B.; Fan, W.; Feege, N.; Fields, D. E.; Finger, M.; Finger, M.; Fleuret, F.; Fokin, S. L.; Frantz, J. E.; Franz, A.; Frawley, A. D.; Fukao, Y.; Fukuda, 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.; Gu, Y.; Gunji, T.; Guragain, H.; 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.; Hayano, R.; He, X.; Hemmick, T. K.; Hester, T.; Hill, J. C.; Hill, K.; Hollis, R. S.; Homma, K.; Hong, B.; Hoshino, T.; Hotvedt, N.; Huang, J.; Huang, S.; Ichihara, T.; Ikeda, Y.; Imai, K.; Imazu, Y.; Imrek, J.; Inaba, M.; Iordanova, A.; Isenhower, D.; Isinhue, A.; Ito, Y.; Ivanishchev, D.; Jacak, B. V.; Jeon, S. J.; Jezghani, M.; Ji, Z.; Jia, J.; Jiang, X.; Johnson, B. M.; Joo, K. S.; Jorjadze, V.; Jouan, D.; Jumper, D. S.; Kamin, J.; Kanda, S.; Kang, B. H.; Kang, J. H.; Kang, J. S.; Kapukchyan, D.; Kapustinsky, J.; Karthas, S.; Kawall, D.; Kazantsev, A. V.; Key, J. A.; Khachatryan, V.; Khandai, P. K.; Khanzadeev, A.; Kijima, K. M.; Kim, C.; Kim, D. J.; Kim, E.-J.; Kim, M.; Kim, M. H.; Kim, Y.-J.; Kim, Y. K.; Kincses, D.; Kistenev, E.; Klatsky, J.; Kleinjan, D.; Kline, P.; Koblesky, T.; Kofarago, M.; Komkov, B.; Koster, J.; Kotchetkov, D.; Kotov, D.; Krizek, F.; Kudo, S.; Kurita, K.; Kurosawa, M.; Kwon, Y.; Lacey, R.; Lai, Y. S.; Lajoie, J. G.; Lallow, E. O.; Lebedev, A.; Lee, D. M.; Lee, G. H.; Lee, J.; Lee, K. B.; Lee, K. S.; Lee, S.; Lee, S. H.; Leitch, M. J.; Leitgab, M.; Leung, Y. H.; Lewis, B.; Lewis, N. A.; Li, X.; Li, X.; Lim, S. H.; Liu, L. D.; Liu, M. X.; Loggins, V.-R.; Loggins, V.-R.; Lökös, S.; Lovasz, K.; Lynch, D.; Maguire, C. F.; Majoros, T.; Makdisi, Y. I.; Makek, M.; Malaev, M.; Manion, A.; Manko, V. I.; Mannel, E.; Masuda, H.; McCumber, M.; McGaughey, P. L.; McGlinchey, D.; McKinney, C.; Meles, A.; Mendoza, M.; Meredith, B.; Metzger, W. J.; Miake, Y.; Mibe, T.; Mignerey, A. C.; Mihalik, D. E.; Milov, A.; Mishra, D. K.; Mitchell, J. T.; Mitsuka, G.; Miyasaka, S.; Mizuno, S.; Mohanty, A. K.; Mohapatra, S.; Montuenga, P.; Moon, T.; Morrison, D. P.; Morrow, S. I. M.; Moskowitz, M.; Moukhanova, T. V.; Murakami, T.; Murata, J.; Mwai, A.; Nagae, T.; Nagai, K.; Nagamiya, S.; Nagashima, K.; Nagashima, T.; Nagle, J. L.; Nagy, M. I.; Nakagawa, I.; Nakagomi, H.; Nakamiya, Y.; Nakamura, K. R.; Nakamura, T.; Nakano, K.; Nattrass, C.; Netrakanti, P. K.; Nihashi, M.; Niida, T.; Nouicer, R.; Novák, T.; Novitzky, N.; Novotny, R.; Nyanin, A. S.; O'Brien, E.; Ogilvie, C. A.; Oide, H.; Okada, K.; Orjuela Koop, J. D.; Osborn, J. D.; Oskarsson, A.; Ottino, G. J.; Ozawa, K.; Pak, R.; Pantuev, V.; Papavassiliou, V.; Park, I. H.; Park, J. S.; Park, S.; Park, S. K.; Pate, S. F.; Patel, L.; Patel, M.; Peng, J.-C.; Peng, W.; Perepelitsa, D. V.; Perera, G. D. N.; Peressounko, D. Yu.; Perezlara, C. E.; Perry, J.; Petti, R.; Phipps, M.; Pinkenburg, C.; Pisani, R. P.; Pun, A.; Purschke, M. L.; Qu, H.; Radzevich, P. V.; Rak, J.; Ravinovich, I.; Read, K. F.; Reynolds, D.; Riabov, V.; Riabov, Y.; Richardson, E.; Richford, D.; Rinn, T.; Riveli, N.; Roach, D.; Rolnick, S. D.; Rosati, M.; Rowan, Z.; Runchey, J.; Ryu, M. S.; Safonov, A. S.; Sahlmueller, B.; Saito, N.; Sakaguchi, T.; Sako, H.; Samsonov, V.; Sarsour, M.; Sato, K.; Sato, S.; Sawada, S.; Schaefer, B.; Schmoll, B. K.; Sedgwick, K.; Seele, J.; Seidl, R.; Sekiguchi, Y.; Sen, A.; Seto, R.; Sett, P.; Sexton, A.; Sharma, D.; Shaver, A.; Shein, I.; Shibata, T.-A.; Shigaki, K.; Shimomura, M.; Shioya, T.; Shoji, K.; Shukla, P.; Sickles, A.; Silva, C. L.; Silvermyr, D.; Singh, B. K.; Singh, C. P.; Singh, V.; Skoby, M. J.; Skolnik, M.; Slunečka, M.; Smith, K. L.; Snowball, M.; Solano, S.; Soltz, R. A.; Sondheim, W. E.; Sorensen, S. P.; Sourikova, I. V.; Stankus, P. W.; Steinberg, P.; Stenlund, E.; Stepanov, M.; Ster, A.; Stoll, S. P.; Stone, M. R.; Sugitate, T.; Sukhanov, A.; Sumita, T.; Sun, J.; Syed, S.; Sziklai, J.; Takahara, A.; Takeda, A.; Taketani, A.; Tanaka, Y.; Tanida, K.; Tannenbaum, M. J.; Tarafdar, S.; Taranenko, A.; Tarnai, G.; Tennant, E.; Tieulent, R.; Timilsina, A.; Todoroki, T.; Tomášek, M.; Torii, H.; Towell, C. L.; Towell, R. S.; Tserruya, I.; Ueda, Y.; Ujvari, B.; van Hecke, H. W.; Vargyas, M.; Vazquez-Carson, S.; Vazquez-Zambrano, E.; Veicht, A.; Velkovska, J.; Vértesi, R.; Virius, M.; Vrba, V.; Vukman, N.; Vznuzdaev, E.; Wang, X. R.; Wang, Z.; Watanabe, D.; Watanabe, K.; Watanabe, Y.; Watanabe, Y. S.; Wei, F.; Whitaker, S.; Wolin, S.; Wong, C. P.; Woody, C. L.; Wysocki, M.; Xia, B.; Xu, C.; Xu, Q.; Xue, L.; Yalcin, S.; Yamaguchi, Y. L.; Yamamoto, H.; Yanovich, A.; Yin, P.; Yokkaichi, S.; Yoo, J. H.; Yoon, I.; You, Z.; Younus, I.; Yu, H.; Yushmanov, I. E.; Zajc, W. A.; Zelenski, A.; Zharko, S.; Zhou, S.; Zou, L.; Phenix Collaboration

2017-12-01

The fraction of J /ψ mesons which come from B -meson decay, FB →J /ψ, is measured for J /ψ rapidity 1.2 <|y |<2.2 and pT>0 in p +p and Cu+Au collisions at √{sNN} = 200 GeV with the PHENIX detector. The extracted fraction is FB →J /ψ=0.025 ±0.006 (stat) ± 0.010(syst) for p +p collisions. For Cu+Au collisions, FB →J /ψ is 0.094 ± 0.028(stat) ± 0.037(syst) in the Au-going direction (-2.2 Cu-going direction (1.2 Au, of B mesons in Cu+Au collisions is consistent with binary scaling of measured yields in p +p at both forward and backward rapidity.

Molecular adsorption properties of CO and H2O on Au-, Cu-, and AuxCuy-doped MoS2 monolayer

NASA Astrophysics Data System (ADS)

Kadioglu, Yelda; Gökoğlu, Gökhan; Üzengi Aktürk, Olcay

2017-12-01

In this study, we investigate the adsorption properties of Au, Cu, and AuxCuy nanoclusters on MoS2 sheet and the interactions of the adsorbed systems with CO and H2O molecules by using first principles calculations. Results indicate that Au, Cu, or AuxCuy strongly binds to MoS2 monolayer resulting in enhanced chemical activity and sensitivity toward CO and H2O molecules compared to bare MoS2 monolayer. Although both CO and H2O molecules bind weakly to pristine MoS2 monolayer, CO strongly binds to MoS2 sheet in the presence of Au, Cu atoms or AuxCuy clusters. Semiconductor MoS2 monolayer turns into metal upon Au or Cu adsorption. AuxCuy nanocluster adsorption decreases the band gap of MoS2 monolayer acting as a n-type dopant. AuxCuy-doped MoS2 systems have improved adsorption properties for CO and H2O molecules, so the conclusions provided in this study can be useful as a guide for next generation device modeling.

Accelerating hydrodynamic description of pseudorapidity density and the initial energy density in p +p , Cu + Cu, Au + Au, and Pb + Pb collisions at energies available at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider

NASA Astrophysics Data System (ADS)

Ze-Fang, Jiang; Chun-Bin, Yang; Csanád, Máté; Csörgő, Tamás

2018-06-01

A known class of analytic, exact, accelerating solutions of prefect relativistic hydrodynamics with longitudinal acceleration is utilized to describe results on the pseudorapidity distributions for different collision systems. These results include d N /d η measured in p +p , Cu+Cu, Au+Au, and Pb+Pb collisions at the BNL Relativistic Heavy Ion Collider and the CERN Large Hadron Collider, in a broad centrality range. Going beyond the traditional Bjorken model, from the accelerating hydrodynamic description we determine the initial energy density and other thermodynamic quantities in those collisions.

Platinum-group element geochemistry used to determine Cu and Au fertility in the Northparkes igneous suites, New South Wales, Australia

NASA Astrophysics Data System (ADS)

Hao, Hongda; Campbell, Ian H.; Park, Jung-Woo; Cooke, David R.

2017-11-01

Recent studies have shown that platinum-group elements (PGE) can be used to constrain the timing of sulfide saturation in evolving felsic systems. In this study, we report trace-element, PGE, Re and Au data for the barren and ore-associated suites of intermediate to felsic rocks from the Northparkes Cu-Au porphyry region, emphasizing the timing of sulfide saturation and its influence on the tenor of the associated hydrothermal mineralization. Two barren suites, the Goonumbla and Wombin Volcanics and associate intrusive rocks, are found in the region. Geochemical modelling shows that the barren suites are dominated by plagioclase-pyroxene fractionation, whereas the ore-associated Northparkes Cu-Au porphyry suite is characterized by plagioclase-amphibole fractionation, which requires the ore-bearing suite to have crystallized from a wetter magma than barren suites. The concentrations of PGE, Re and Au in the barren suites decrease continuously during fractional crystallization. This is attributed to early sulfide saturation with the fraction of immiscible sulfide precipitation required to produce the observed trend, being 0.13 and 0.16 wt.% for the Goonumbla and Wombin suites, respectively. The calculated partition coefficients for Au and Pd required to model the observed change in these elements with MgO are well below published values, indicating that R, the mass ratio of silicate to sulfide melt, played a significant role in controlling the rate of decline of these elements with fractionation. Palladium in the ore-associated suite, in contrast, first increases with fractionation then decreases abruptly at 1.2 wt.% MgO. The sharp decrease is attributed to the onset of sulfide precipitation. Platinum on the other hand shows a moderate decrease, starting from the highest MgO sample analysed, but then decreasing strongly from 1.2 wt.% MgO. The initial Pt decrease is attributed to precipitation of a platinum-group mineral (PGM), probably a Pt-Fe alloy, and the sharp

Role of Dispersion in Metallophilic Hg···M Interactions (M = Cu, Ag, Au) within Coinage Metal Complexes of Bis(6-diphenylphosphinoacenaphth-5-yl)mercury.

PubMed

Hupf, Emanuel; Kather, Ralf; Vogt, Matthias; Lork, Enno; Mebs, Stefan; Beckmann, Jens

2016-11-07

The previously reported bis(6-diphenylphosphinoacenaphth-5-yl)mercury (1) was used as ligand for the preparation of the copper(I) complexes, 1·CuCl and [1·Cu(NCMe)]BF 4 , which were characterized by multinuclear NMR spectroscopy and X-ray crystallography. DFT calculations employing topological analysis of the electron and electron pair densities within the AIM and ELI-D space-partitioning schemes revealed significant metallophilic Hg···Cu interactions. Evaluation of noncovalent bonding aspects according to the noncovalent interaction (NCI) index was applied not only for the Cu complexes 1·CuCl and [1·Cu(NCMe)]BF 4 but also for the previously reported Ag and Au complexes, namely, [1·MCl] (M = Ag, Au) and [1·M(NCMe) n ] + (M = Ag, n = 2; M = Au, n = 0), and facilitated the assignment of attractive dispersive Hg···M interactions with the Hg···Cu contacts being comparable to the Hg···Ag but weaker than the Hg···Au interactions. The localization of the attractive noncovalent bonding regions increases in the order Cu < Ag < Au.

Iron mineralization and associated skarn development around southern contact of the Eğrigöz pluton (northern Menderes Massif-Turkey)

NASA Astrophysics Data System (ADS)

Uǧurcan, Okşan Gökçen; Oyman, Tolga

2016-11-01

The Eğrigöz pluton is located in the northern portion of the Menderes Massif, which is the largest known metamorphic core complex that is also characterized by large-scale extension. Kalkan and Karaağıl skarn deposits are located on the southern border of the Eğrigöz Pluton, whereas Katrandağ mineralization developed along the roof pendant. Skarnization in these three areas is associated with the peraluminous, I-type, calc-alkaline, high-K calc-alkaline Eğrigöz Pluton. Geochemical characteristics of the pluton indicate that it was generated in a continental arc setting. Kalkan, Karaağıl, and Katrandağ skarns are hosted in marble bands in two-mica gneiss of the Kalkan Formation, a locally dolomitic and clay-bearing limestone of the Arıkaya Formation and locally dolomitised limestone of the Balıkbaşı Formation, respectively. Skarn development occurred sequentially in two stages, prograde and retrograde. In Kalkan skarn, prograde stage is characterized by clinopyroxene (Di56-73 Hd26-43 Joh1-2), garnet (Adr45-69 Grs30-52 Alm0-1.4 Sps0.7-2.3), amphibole, and magnetite, whereas retrograde stage is dominated by epidote, amphibole, chlorite, quartz, and calcite. In Karaağıl, both calcic and magnesian skarn association occurred as a result of local variations in dolomite content in Arıkaya Formation. The prograde assemblage of magnesian skarn is composed chiefly of spinel, amphibole and olivine. These mineral assemblages were, partially or fully, altered to serpentine, talc, and chlorite during retrograde alteration. Mesh textures of the serpentine indicates that the serpentine was altered from olivine. Olivine was completely destroyed during retrograde alteration without relict grains remaining. Calcic skarn paragenesis include garnet (Grs36-80Adr20-62Alm0-2.2Sps0.2-2.6), clinopyroxene (Di81-92 Hd7-19 Jo0-1), and plagioclase, that belongs to the earlier stage, and amphibole of the retrograde stage. High grossular end member of the garnet probably

Stable and Efficient CuO Based Photocathode through Oxygen-Rich Composition and Au-Pd Nanostructure Incorporation for Solar-Hydrogen Production.

PubMed

Masudy-Panah, Saeid; Siavash Moakhar, Roozbeh; Chua, Chin Sheng; Kushwaha, Ajay; Dalapati, Goutam Kumar

2017-08-23

Enhancing stability against photocorrosion and improving photocurrent response are the main challenges toward the development of cupric oxide (CuO) based photocathodes for solar-driven hydrogen production. In this paper, stable and efficient CuO-photocathodes have been developed using in situ materials engineering and through gold-palladium (Au-Pd) nanoparticles deposition on the CuO surface. The CuO photocathode exhibits a photocurrent generation of ∼3 mA/cm 2 at 0 V v/s RHE. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis and X-ray spectroscopy (XPS) confirm the formation of oxygen-rich (O-rich) CuO film which demonstrates a highly stable photocathode with retained photocurrent of ∼90% for 20 min. The influence of chemical composition on the photocathode performance and stability has been discussed in detail. In addition, O-rich CuO photocathodes deposited with Au-Pd nanostructures have shown enhanced photoelectrochemical performance. Linear scan voltammetry characteristic shows ∼25% enhancement in photocurrent after Au-Pd deposition and reaches ∼4 mA/cm 2 at "0" V v/s RHE. Hydrogen evolution rate significantly depends on the elemental composition of CuO and metal nanostructure. The present work has demonstrated a stable photocathode with high photocurrent for visible-light-driven water splitting and hydrogen production.

The effect of long-range order on the elastic properties of Cu3Au

NASA Astrophysics Data System (ADS)

Wang, Gui-Sheng; Krisztina Delczeg-Czirjak, Erna; Hu, Qing-Miao; Kokko, Kalevi; Johansson, Börje; Vitos, Levente

2013-02-01

Ab initio calculations, based on the exact muffin-tin orbitals method are used to determine the elastic properties of Cu-Au alloys with Au/Cu ratio 1/3. The compositional disorder is treated within the coherent potential approximation. The lattice parameters and single-crystal elastic constants are calculated for different partially ordered structures ranging from the fully ordered L12 to the random face centered cubic lattice. It is shown that the theoretical elastic constants follow a clear trend with the degree of chemical order: namely, C11 and C12 decrease, whereas C44 remains nearly constant with increasing disorder. The present results are in line with the experimental findings that the impact of the chemical ordering on the fundamental elastic parameters is close to the resolution of the available experimental and theoretical tools.

Mechanical properties and structure evolution of single-crystalline silicon irradiated by 1 MeV Au+ and Cu+ ions

NASA Astrophysics Data System (ADS)

Liang, Wei; Zhu, Fei; Ling, Yunhan; Liu, Kezhao; Hu, Yin; Pan, Qifa; Chen, Limin; Zhang, Zhengjun

2018-05-01

Mechanical and structural evolutions of single-crystalline silicon irradiated by a series of doses 1 MeV Au+ ions and Cu+ ions are characterized by Surface laser-acoustic wave spectroscopy by (LA wave), Rutherford backscattering spectrometry and channeling (RBS/C) and transmission electron microscopy (TEM). The behavior of implanted Au+ and Cu+ ions was also simulated by using Stopping and range of ions in matter (SRIM) software package, respectively. It is demonstrated that LA wave and RBS could be applied for accurate evaluation of the TEM observed amorphous layer's thickness. The modified mechanical properties depend on the species and the dose of implantation. For 1 MeV Au+ ions, the threshold dose of completely amorphous is 5 × 1014 atoms/cm2, while the one for Cu+ ions is 5 × 1015 atoms/cm2. Upon completely amorphous, the young's modulus and layer density decreased significantly while saturated with the dose increasing sequentially.

Effect of thione primers on adhesive bonding between an indirect composite material and Ag-Pd-Cu-Au alloy.

PubMed

Imai, Hideyuki; Koizumi, Hiroyasu; Shimoe, Saiji; Hirata, Isao; Matsumura, Hideo; Nikawa, Hiroki

2014-01-01

The current study evaluated the effect of primers on the shear bond strength of an indirect composite material joined to a silverpalladium-copper-gold (Ag-Pd-Cu-Au) alloy (Castwell). Disk specimens were cast from the alloy and were air-abraded with alumina. Eight metal primers were applied to the alloy surface. A light-polymerized indirect composite material (Solidex) was bonded to the alloy. Shear bond strength was determined both before and after the application of thermocycling. Two groups primed with Metaltite (thione) and M. L. Primer (sulfide) showed the greatest post-thermocycling bond strength (8.8 and 6.5 MPa). The results of the X-ray photoelectron spectroscopic (XPS) analysis suggested that the thione monomer (MTU-6) in the Metaltite primer was strongly adsorbed onto the Ag-Pd-Cu-Au alloy surface even after repeated cleaning with acetone. The application of either the thione (MTU-6) or sulfide primer is effective for enhancing the bonding between a composite material and Ag-Pd-Cu-Au alloy.

Dramatically enhanced non-Ohmic properties and maximum stored energy density in ceramic-metal nanocomposites: CaCu3Ti4O12/Au nanoparticles

PubMed Central

2013-01-01

Non-Ohmic and dielectric properties of a novel CaCu3Ti4O12/Au nanocomposite were investigated. Introduction of 2.5 vol.% Au nanoparticles in CaCu3Ti4O12 ceramics significantly reduced the loss tangent while its dielectric permittivity remained unchanged. The non-Ohmic properties of CaCu3Ti4O12/Au (2.5 vol.%) were dramatically improved. A nonlinear coefficient of ≈ 17.7 and breakdown electric field strength of 1.25 × 104 V/m were observed. The maximum stored energy density was found to be 25.8 kJ/m3, which is higher than that of pure CaCu3Ti4O12 by a factor of 8. Au addition at higher concentrations resulted in degradation of dielectric and non-Ohmic properties, which is described well by percolation theory. PMID:24257060

A density functional global optimisation study of neutral 8-atom Cu-Ag and Cu-Au clusters

NASA Astrophysics Data System (ADS)

Heard, Christopher J.; Johnston, Roy L.

2013-02-01

The effect of doping on the energetics and dimensionality of eight atom coinage metal subnanometre particles is fully resolved using a genetic algorithm in tandem with on the fly density functional theory calculations to determine the global minima (GM) for Cu n Ag(8- n) and Cu n Au(8- n) clusters. Comparisons are made to previous ab initio work on mono- and bimetallic clusters, with excellent agreement found. Charge transfer and geometric arguments are considered to rationalise the stability of the particular permutational isomers found. An interesting transition between three dimensional and two dimensional GM structures is observed for copper-gold clusters, which is sharper and appears earlier in the doping series than is known for gold-silver particles.

Molecular dynamics simulation of the coalescence and melting process of Au and Cu nano-clusters

NASA Astrophysics Data System (ADS)

Chen, Gang; Wang, Chuan Jie; Zhang, Peng

2018-03-01

Molecular dynamic (MD) method is used to study the coalescence and fusing process of Au and Cu nanoclusters. The results show that shear deformation, surface and interface diffusion play important role in different stages of all simulation procedure. In most cases, shear deformation produces the twin boundary or/and stacking fault in particles by particle rotation and slide. The angle between the {111} of Au and Cu particles decrease with increasing temperature, which promotes the formation of the stable interface. Furthermore, the coalescence point and melting temperature increase as cluster diameter increases. For the other cases, there are no particle rotation and slide phenomenon in the elevating temperature process because the stable interface can be formed by forming twin boundaries once two particles contact.

Au-iClick mirrors the mechanism of copper catalyzed azide–alkyne cycloaddition (CuAAC)

DOE PAGES

Powers, Andrew R.; Ghiviriga, Ion; Abboud, Khalil A.; ...

2015-07-20

This report outlines the investigation of the iClick mechanism between gold(I)-azides and gold(I)-acetylides to yield digold triazolates. Isolation of digold triazolate complexes offer compelling support for the role of two copper(I) ions in CuAAC. In addition, a kinetic investigation reveals the reaction is first order in both Au(I)-N 3 and Au(I)-C≡C-R equivalent to C-R, thus second order overall. A Hammett plot with a ρ = 1.02(5) signifies electron-withdrawing groups accelerate the cycloaddition by facilitating the coordination of the second gold ion in a π-complex. Rate inhibition by the addition of free triphenylphosphine to the reaction indicates that ligand dissociation ismore » a prerequisite for the reaction. The mechanistic conclusions mirror those proposed for the CuAAC reaction.« less

Facile synthesis, pharmacokinetic and systemic clearance evaluation, and positron emission tomography cancer imaging of 64Cu-Au alloy nanoclusters

NASA Astrophysics Data System (ADS)

Zhao, Yongfeng; Sultan, Deborah; Detering, Lisa; Luehmann, Hannah; Liu, Yongjian

2014-10-01

Gold nanoparticles have been widely used for oncological applications including diagnosis and therapy. However, the non-specific mononuclear phagocyte system accumulation and potential long-term toxicity have significantly limited clinical translation. One strategy to overcome these shortcomings is to reduce the size of gold nanoparticles to allow renal clearance. Herein, we report the preparation of 64Cu alloyed gold nanoclusters (64CuAuNCs) for in vivo evaluation of pharmacokinetics, systemic clearance, and positron emission tomography (PET) imaging in a mouse prostate cancer model. The facile synthesis in acqueous solution allowed precisely controlled 64Cu incorporation for high radiolabeling specific activity and stability for sensitive and accurate detection. Through surface pegylation with 350 Da polyethylene glycol (PEG), the 64CuAuNCs-PEG350 afforded optimal biodistribution and significant renal and hepatobiliary excretion. PET imaging showed low non-specific tumor uptake, indicating its potential for active targeting of clinically relevant biomarkers in tumor and metastatic organs.Gold nanoparticles have been widely used for oncological applications including diagnosis and therapy. However, the non-specific mononuclear phagocyte system accumulation and potential long-term toxicity have significantly limited clinical translation. One strategy to overcome these shortcomings is to reduce the size of gold nanoparticles to allow renal clearance. Herein, we report the preparation of 64Cu alloyed gold nanoclusters (64CuAuNCs) for in vivo evaluation of pharmacokinetics, systemic clearance, and positron emission tomography (PET) imaging in a mouse prostate cancer model. The facile synthesis in acqueous solution allowed precisely controlled 64Cu incorporation for high radiolabeling specific activity and stability for sensitive and accurate detection. Through surface pegylation with 350 Da polyethylene glycol (PEG), the 64CuAuNCs-PEG350 afforded optimal

Native gold from the Inagli Pt-Au placer deposit (the Aldan Shield, Russia): geochemical characteristics and implications for possible bedrock sources

NASA Astrophysics Data System (ADS)

Svetlitskaya, Tatyana V.; Nevolko, Peter A.; Kolpakov, Vladislav V.; Tolstykh, Nadezhda D.

2018-03-01

The Inagli alluvial Pt-Au placer deposit in the Republic of Sakha (Yakutia), Russia, is linked to the Inagli massif, one of the several Uralian-Alaskan-type alkaline-ultrabasic complexes in the Aldan Shield. Gold from the placer is heterogeneous in composition and is represented by three types. Type 1 gold is the most abundant and is characterized by simple Au-Ag alloys with 4-34 wt% Ag, low Cu (up to 0.08 wt%) and negligible Hg, Pt, and Pd contents, and silver-tellurium sulfosalts (Ag-Cu-Te-S-As compounds) in the inclusion suite. Silicate inclusions are biotite, K-feldspar, Fe-Mg amphibole, chlorite, plagioclase, Fe-Mg pyroxene, zircon, and titanite. Distinctive features of this gold type are most similar to those derived from low-sulfidation systems linked to iron oxide copper-gold or iron skarn types of mineralization. The bedrock source of type 1 gold could be related with monzonite to syenite intrusions surrounding the Inagli massif. Distinctive features of type 2 gold include a wide discontinuous range of Ag content (1-18 wt%), elevated Cu (up to 0.5 wt%), and occasional Pd (up to 0.3 wt%) levels, non-detectable Pt and Hg contents, and rare inclusions of simple sulfides (digenite, pyrrhotite) and Na amphibole. Type 3 gold is distinguished by a narrow range in Ag content (5-8 wt%), elevated Hg (0.5-1 wt%) contents, negligible Cu, Pt and Pd levels, and Au-Pb compounds + K-feldspar inclusions. Microchemical characteristics of type 2 and type 3 gold are interpreted as suggestive of an alkaline-magmatic-related fluid. Based on the grain morphology and microchemical signatures, potential bedrock sources for both gold types could be related to the numerous alkaline veins and potassic alteration zones within the dunite core. A comparison of the Inagli and the Kondyor placer gold allows to generate distinctive generic signatures for gold from Uralian-Alaskan-type alkaline-ultrabasic complexes in the Aldan Shield.

Stopping power of Au for Cu ions with energies below Bragg’s peak

NASA Astrophysics Data System (ADS)

Linares, R.; Freire, J. A.; Ribas, R. V.; Medina, N. H.; Oliveira, J. R. B.; Cybulska, E. W.; Seale, W. A.; Added, N.; Silveira, M. A. G.; Wiedemann, K. T.

2007-10-01

The stopping power of Au for Cu in the energy range 6 < E < 25 MeV was measured using a secondary beam of low velocity heavy ions produced by elastic scattering of an energetic primary beam (typically 28Si or 16O) on a natural Cu target. The results were compared to predictions of the Lindhard, Scharf and Schiott (LSS) theory, the binary theory (BT), and the unitary convolution approximation (UCA) and also to semi-empirical predictions such as the Northcliffe and Schilling tables and the SRIM2003 computer program.

Geochronology and petrogenesis of the Qibaoshan Cu-polymetallic deposit, northeastern Hunan Province: Implications for the metal source and metallogenic evolution of the intracontinental Qinhang Cu-polymetallic belt, South China

NASA Astrophysics Data System (ADS)

Yuan, Shunda; Mao, Jingwen; Zhao, Panlao; Yuan, Yabin

2018-03-01

The recently recognized Qinhang metallogenic belt (QHMB) is an economically important intracontinental Mesozoic porphyry-skarn Cu-polymetallic metallogenic belt in South China. However, the origin of the ore-bearing magma and the major factors controlling the different metal assemblages in the QHMB are still unclear. The Qibaoshan deposit is a large Cu-Au-Pb-Zn-Ag-Fe deposit located at the juncture between the northern and central parts of the QHMB. In this study, new zircon U-Pb ages, Hf-O isotopic data, molybdenite Re-Os ages, and whole-rock geochemical data are combined to constrain the timing of the mineralization and the origin and petrogenesis of the ore-bearing porphyry in the Qibaoshan deposit. The ages obtained from both zircon U-Pb and molybdenite Re-Os dating fall in the Late Jurassic (between 152.7 and 148.3 Ma), revealing that this deposit is significantly younger than previously estimated (227-184 Ma). The Qibaoshan ore-bearing quartz porphyry shows variable negative zircon εHf(t) values (-14.8 to -5.5), high δ18O values (8.4 to 10.8‰), and high Mg# values (69.1 to 73.0), indicating that it formed via the partial melting of ancient crust triggered by the injection of mantle-derived magma. Zircon Hf-O isotopic modeling of the mixing of two extreme endmembers indicates that the magmatic source comprised 70-80% reworked ancient crustal components and 20-30% depleted mantle components. Based on comparisons with other ore-bearing porphyries in the QHMB, a magmatic source dominated by crust-derived material and relatively low oxygen fugacities (ΔFMQ -1.8 to ΔFMQ +0.8) was responsible for the high (Pb + Zn)/Cu ratio in the Qibaoshan deposit, and the Pb, Zn and Ag were mainly derived from the reworked ancient crust. Although four analyses of inherited Neoproterozoic zircons ( 800 Ma) have variable positive εHf(t) values (0.72 to 11.21), indicating that Neoproterozoic juvenile crust was involved in the formation of the Qibaoshan ore-bearing quartz

Analysis of aging time dependent electrical characteristics of AuCu/n-Si/Ti Schottky type diode

NASA Astrophysics Data System (ADS)

Taser, Ahmet; Şenarslan, Elvan; Güzeldir, Betül; Saǧlam, Mustafa

2017-04-01

The purpose of this study is to fabricate AuCu/n-Si/Ti Schottky type diode and determine the effects of aging time on the diode parameters such as ideality factor, barrier height, series resistance, interface state density and rectification ratio. Gold and copper ratios in the gold-copper alloy used in making the Schottky contact were taken as equal. Schottky barrier contact using AuCu alloy and ohmic contact using Ti metal were made on n-Si by thermal evaporation. The electrical characterization of the AuCu/n-Si/Ti diode was made immediately based on the aging time at room temperature in dark conditions. The I-V measurements were also repeated 1, 7, 15, 30 and 90 days after fabrication of the diode in order to observe the effect of the aging time. The determined values of the ideality factor are in the range of 1,21 (for immediately)-1,075 (for 90 days). In the same way, values of the barrier height are also in the range of 0,566 eV (for immediately)-0,584 eV (for 90 days). From the I-V characteristics, it is seen that the diode appears to have a good rectification character.

Stability of M 3S 3 complexes on fcc M(111) surfaces: M = Au, Ag, Cu, and Ni

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Da-Jiang; Lee, Jiyoung; Windus, Theresa L.

Density Functional Theory is utilized to assess the stability of metal (M)-sulfur (S) complexes adsorbed on fcc M(111) surfaces, specifically considering S-decorated planar M trimers, M 3S 3. Scanning Tunneling Microscopy studies have identified structures proposed to be Ni 3S 3 on Ni(111), and Au 3S 3 on Au(111). In addition, Cu 3S 3 on Cu(111) has been suggested to facilitate enhanced Cu surface mass transport. Our analysis considers M 3S 3 complexes for M = Au, Ag, Cu, and Ni, assessing key measures of stability on surfaces, and also comparing behavior with trends in gas-phase stability. These surface andmore » gas-phase analyses are systematically related within the framework of Hess’s law, which allows elucidation of various contributions to the overall energetics. In all cases, the adsorbed complex is stable relative to its separated constituents adsorbed on the terrace. However, only for Ag does one find a negative energy of formation from excess S on terraces and M extracted from kink sites along step edges, implying spontaneous complex formation for this pathway. We interpret various experimental observations in the context of our results for energetics.« less

Stability of M 3S 3 complexes on fcc M(111) surfaces: M = Au, Ag, Cu, and Ni

DOE PAGES

Liu, Da-Jiang; Lee, Jiyoung; Windus, Theresa L.; ...

2018-02-08

Density Functional Theory is utilized to assess the stability of metal (M)-sulfur (S) complexes adsorbed on fcc M(111) surfaces, specifically considering S-decorated planar M trimers, M 3S 3. Scanning Tunneling Microscopy studies have identified structures proposed to be Ni 3S 3 on Ni(111), and Au 3S 3 on Au(111). In addition, Cu 3S 3 on Cu(111) has been suggested to facilitate enhanced Cu surface mass transport. Our analysis considers M 3S 3 complexes for M = Au, Ag, Cu, and Ni, assessing key measures of stability on surfaces, and also comparing behavior with trends in gas-phase stability. These surface andmore » gas-phase analyses are systematically related within the framework of Hess’s law, which allows elucidation of various contributions to the overall energetics. In all cases, the adsorbed complex is stable relative to its separated constituents adsorbed on the terrace. However, only for Ag does one find a negative energy of formation from excess S on terraces and M extracted from kink sites along step edges, implying spontaneous complex formation for this pathway. We interpret various experimental observations in the context of our results for energetics.« less

Composition and source of salinity of ore-bearing fluids in Cu-Au systems of the Carajás Mineral Province, Brazil

USGS Publications Warehouse

Xavier, Roberto; Rusk, Brian; Emsbo, Poul; Monteiro, Lena

2009-01-01

The composition and Cl/Br – NaCl ratios of highly saline aqueous inclusions from large tonnage (> 100 t) IOCG deposits (Sossego, Alvo 118, and Igarapé Bahia) and a Paleoproterozoic intrusion-related Cu-Au-(Mo-W-Bi-Sn) deposit (Breves; < 50 Mt)) in the Carajás Mineral Province have been analysed by LA-ICP-MS and ion chromatography. In both Cu-Au systems, brine inclusions are Ca-dominated (5 to 10 times more than in porphyry Cu-Au fluids), and contain percent level concentrations of Na and K. IOCG inclusion fluids, however, contain higher Sr, Ba, Pb, and Zn concentrations, but significantly less Bi, than the intrusion-related Breves inclusion fluids. Cu is consistently below detection limits in brine inclusions from the IOCG and intrusion-related systems and Fe was not detected in the latter. Cl/Br and Na/Cl ratios of the IOCG inclusion fluids range from entirely evaporative brines (bittern fluids; e.g. Igarapé Bahia and Alvo 118) to values that indicate mixing with magma-derived brines. Cl/Br and Na/Cl ratios of the Breves inclusion fluids strongly suggest the involvement of magmatic brines, but that possibly also incorporated bittern fluids. Collectively, these data demonstrate that residual evaporative and magmatic brines were important components of the fluid regime involved in the formation of Cu-Au systems in the Carajás Mineral Province.

Sulfonated poly(ether ether ketone)/poly(vinyl alcohol) sensitizing system for solution photogeneration of small Ag, Au, and Cu crystallites.

PubMed

Korchev, A S; Shulyak, T S; Slaten, B L; Gale, W F; Mills, G

2005-04-28

Illumination of air-free aqueous solutions containing sulfonated poly(ether ether ketone) and poly(vinyl alcohol) with 350 nm light results in benzophenone ketyl radicals of the polyketone. The polymer radicals form with a quantum yield 0.02 and decay with a second-order rate constant 6 orders of magnitude lower than that of typical alpha-hydroxy radicals. Evidence is presented that the polymeric benzophenone ketyl radicals reduce Ag+, Cu2+, and AuCl4- to metal particles of nanometer dimensions. Decreases in the reduction rates with increasing Ag(I), Cu(II), and Au(III) concentrations are explained using a kinetic model in which the metal ions quench the excited state of the polymeric benzophenone groups, which forms the macromolecular radicals. Quenching is fastest for Ag+, whereas Cu2+ and AuCl4- exhibit similar rate constants. Particle formation becomes more complex as the number of equivalents needed to reduce the metal ions increases; the Au(III) system is an extreme case where the radical reactions operate in parallel with secondary light-initiated and thermal reduction channels. For each metal ion, the polymer-initiated photoreactions produce crystallites possessing distinct properties, such as a very strong plasmon in the Ag case or the narrow size distribution exhibited by Au particles.

Surface investigation of Si(1 0 0), Cu, Cu on Si(1 0 0), and Au on Cu with positron annihilation induced Auger-electron spectroscopy

NASA Astrophysics Data System (ADS)

Hugenschmidt, C.; Mayer, J.; Schreckenbach, K.

2007-06-01

The surfaces of polycrystalline Cu, Au-coated Cu, Si(1 0 0) and of Si(1 0 0) coated with 1.5 monolayer Cu were investigated with positron annihilation induced Auger-electron spectroscopy (PAES). Since the electron background has been reduced considerably we observed the Cu M 2,3VV-Auger transition on a copper surface within only three hours which is the shortest acquisition time reported so far for PAES. In order to demonstrate PAES' high potential the Auger-yield, the signal-to-background ratio as well as the surface selectivity were compared with accompanying EAES-measurements quantitatively. A more efficient electron energy analyzer for the present PAES setup would lead to an additional efficiency gain of more than two orders of magnitude. The presented measurements were performed at the low-energy positron beam of high intensity NEPOMUC at the research reactor FRM II.

Strongly enhanced Raman scattering of Cu-phthalocyanine sandwiched between graphene and Au(111).

PubMed

Lin, Wan-Ing; Gholami, Mohammad Fardin; Beyer, Paul; Severin, Nikolai; Shao, Feng; Zenobi, Renato; Rabe, Jürgen P

2017-01-05

Graphene and flat gold have both been argued to enhance Raman scattering of molecular adsorbates through a chemical mechanism. Here we show that these two effects can add to each other. For Cu-phthalocyanine in between graphene and Au(111) on mica a Raman enhancement up to 68-fold has been observed.

Multiphase formation of the Obří důl polymetallic skarn deposit, West Sudetes, Bohemian Massif: geochemistry and Re-Os dating of sulfide mineralization

NASA Astrophysics Data System (ADS)

Veselovský, František; Ackerman, Lukáš; Pašava, Jan; Žák, Karel; Haluzová, Eva; Creaser, Robert A.; Dobeš, Petr; Erban, Vojtěch; Tásler, Radko

2017-10-01

The Obří důl Fe-Cu-As polymetallic sulfide skarn deposit is developed in a metamorphic series in the West Sudetes, Bohemian Massif. It consists of lenses of marble, calc-silicate rocks, and skarns. We studied the Gustav orebody, which is located few hundred meters away from the contact with a large, late-orogenic Variscan Krkonoše-Jizera Plutonic Complex (KJPC) emplaced into shallow crust. Mineralogical and fluid inclusion study evidence indicates that the main sulfide stage, dominated by pyrrhotite, arsenopyrite, and chalcopyrite originated from aqueous hydrothermal fluids with salinity up to 8 wt% NaCl eq. with minimum homogenization temperatures ranging from 324 to 358 °C. These fluids mainly replaced carbonate-rich lithologies. Carbon, oxygen, and strontium isotope data in Ca-rich rocks imply total overprinting by channelized metasomatic fluid flow, which is most probably related to the intrusion of the KJPC, whereas δ34S values of sulfides argue for a magmatic source of sulfur. The Re-Os age of arsenopyrite overlaps published age data for the KJPC and suggests synchronous formation of the main sulfide mineralization and pluton emplacement.

Multiphase formation of the Obří důl polymetallic skarn deposit, West Sudetes, Bohemian Massif: geochemistry and Re-Os dating of sulfide mineralization

NASA Astrophysics Data System (ADS)

Veselovský, František; Ackerman, Lukáš; Pašava, Jan; Žák, Karel; Haluzová, Eva; Creaser, Robert A.; Dobeš, Petr; Erban, Vojtěch; Tásler, Radko

2018-06-01

The Obří důl Fe-Cu-As polymetallic sulfide skarn deposit is developed in a metamorphic series in the West Sudetes, Bohemian Massif. It consists of lenses of marble, calc-silicate rocks, and skarns. We studied the Gustav orebody, which is located few hundred meters away from the contact with a large, late-orogenic Variscan Krkonoše-Jizera Plutonic Complex (KJPC) emplaced into shallow crust. Mineralogical and fluid inclusion study evidence indicates that the main sulfide stage, dominated by pyrrhotite, arsenopyrite, and chalcopyrite originated from aqueous hydrothermal fluids with salinity up to 8 wt% NaCl eq. with minimum homogenization temperatures ranging from 324 to 358 °C. These fluids mainly replaced carbonate-rich lithologies. Carbon, oxygen, and strontium isotope data in Ca-rich rocks imply total overprinting by channelized metasomatic fluid flow, which is most probably related to the intrusion of the KJPC, whereas δ34S values of sulfides argue for a magmatic source of sulfur. The Re-Os age of arsenopyrite overlaps published age data for the KJPC and suggests synchronous formation of the main sulfide mineralization and pluton emplacement.

Controlling Magnetism via Transition Metal Exchange in the Series of Intermetallics Eu( T1, T2)5In ( T = Cu, Ag, Au)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mudring, Anja -Verena; Smetana, Volodymyr; Pecharsky, Vitalij K.

Three series of intermetallic compounds Eu( T1, T2) 5In (T = Cu, Ag, Au) have been investigated in full compositional ranges. Single crystals of all compounds have been obtained by self-flux and were analyzed by single X-ray diffraction revealing the representatives to fall into two structure types: CeCu 6 ( oP28, Pnma, a = 8.832(3)–9.121(2) Å, b = 5.306(2)–5.645(1) Å, c = 11.059(4)–11.437(3) Å, V = 518.3(3)–588.9(2) Å 3) and YbMo2Al4 ( t I14, I4/ mmm, a = 5.417(3)–5.508(1) Å, c = 7.139(2)– 7.199(2) Å, V = 276.1(2)–285.8(1) Å 3). The structural preference was found to depend on the cation/anionmore » size ratio, while the positional preference within the CeCu 6 type structure shows an apparent correlation with the anion size. Chemical compression, hence, a change in cell volume, which occurs upon anion substitution appears to be the main driving force for the change of magnetic ordering. While EuAg 5In shows antiferromagnetic behavior at low temperatures, mixing Cu and Au within the same type of structure results in considerable changes in the magnetism. The Eu(Cu,Au) 5In alloys with CeCu 6 structure show complex magnetic behaviors and strong magnetic field-induced spin-reorientation transition with the critical field of the transition being dependent on Cu/Au ratio. The alloys adopting the YbMo 2Al 4 type structure are ferromagnets exhibiting unusually high magnetic moments. The heat capacity of EuAu 2.66Cu 2.34In reveals a double-peak structure evolving with the magnetic field. Furthermore, low-temperature X-ray powder diffraction does not show a structural transition.« less

Controlling Magnetism via Transition Metal Exchange in the Series of Intermetallics Eu( T1, T2)5In ( T = Cu, Ag, Au)

DOE PAGES

Mudring, Anja -Verena; Smetana, Volodymyr; Pecharsky, Vitalij K.; ...

2017-11-24

Three series of intermetallic compounds Eu( T1, T2) 5In (T = Cu, Ag, Au) have been investigated in full compositional ranges. Single crystals of all compounds have been obtained by self-flux and were analyzed by single X-ray diffraction revealing the representatives to fall into two structure types: CeCu 6 ( oP28, Pnma, a = 8.832(3)–9.121(2) Å, b = 5.306(2)–5.645(1) Å, c = 11.059(4)–11.437(3) Å, V = 518.3(3)–588.9(2) Å 3) and YbMo2Al4 ( t I14, I4/ mmm, a = 5.417(3)–5.508(1) Å, c = 7.139(2)– 7.199(2) Å, V = 276.1(2)–285.8(1) Å 3). The structural preference was found to depend on the cation/anionmore » size ratio, while the positional preference within the CeCu 6 type structure shows an apparent correlation with the anion size. Chemical compression, hence, a change in cell volume, which occurs upon anion substitution appears to be the main driving force for the change of magnetic ordering. While EuAg 5In shows antiferromagnetic behavior at low temperatures, mixing Cu and Au within the same type of structure results in considerable changes in the magnetism. The Eu(Cu,Au) 5In alloys with CeCu 6 structure show complex magnetic behaviors and strong magnetic field-induced spin-reorientation transition with the critical field of the transition being dependent on Cu/Au ratio. The alloys adopting the YbMo 2Al 4 type structure are ferromagnets exhibiting unusually high magnetic moments. The heat capacity of EuAu 2.66Cu 2.34In reveals a double-peak structure evolving with the magnetic field. Furthermore, low-temperature X-ray powder diffraction does not show a structural transition.« less

Adjustable coordination of a hybrid phosphine-phosphine oxide ligand in luminescent Cu, Ag and Au complexes.

PubMed

Dau, Thuy Minh; Asamoah, Benjamin Darko; Belyaev, Andrey; Chakkaradhari, Gomathy; Hirva, Pipsa; Jänis, Janne; Grachova, Elena V; Tunik, Sergey P; Koshevoy, Igor O

2016-09-28

A potentially tridentate hemilabile ligand, PPh2-C6H4-PPh(O)-C6H4-PPh2 (P(3)O), has been used for the construction of a family of bimetallic complexes [MM'(P(3)O)2](2+) (M = M' = Cu (1), Ag (2), Au (3); M = Au, M' = Cu (4)) and their mononuclear halide congeners M(P(3)O)Hal (M = Cu (5-7), Ag (8-10)). Compounds 1-10 have been characterized in the solid state by single-crystal X-ray diffraction analysis to reveal a variable coordination mode of the phosphine-oxide group of the P(3)O ligand depending on the preferable number of coordination vacancies on the metal center. According to the theoretical studies, the interaction of the hard donor P[double bond, length as m-dash]O moiety with d(10) ions becomes less effective in the order Cu > Ag > Au. 1-10 exhibit room temperature luminescence in the solid state, and the intensity and energy of emission are mostly determined by the nature of metal atoms. The photophysical characteristics of the monometallic species were compared with those of the related compounds M(P(3))Hal (11-16) with the non-oxidized ligand P(3). It was found that in the case of the copper complexes 5-7 the P(3)O hybrid ligand introduces effective non-radiative pathways of the excited state relaxation leading to poor emission, while for the silver luminophores the P[double bond, length as m-dash]O group leads mainly to the modulation of luminescence wavelength.

Geochronological framework of the early Paleozoic Bainaimiao Cu-Mo-Au deposit, NE China, and its tectonic implications

NASA Astrophysics Data System (ADS)

Zhou, Zhen-Hua; Mao, Jing-Wen; Ma, Xing-Hua; Che, He-Wei; Ou'yang, He-Gen; Gao, Xu

2017-08-01

The Bainaimiao Cu-Mo-Au deposit of NE China is an important ore deposit in the middle section of the northern margin of the North China Craton. The early Paleozoic Bainaimiao Group is the main ore-hosting rock. The mineralization at the deposit shows features of porphyry alteration and late-stage orogenesis and transformation. Zircon LA-ICP-MS U-Pb age data indicate that the ages of the Third and Fifth formations of the Bainaimiao Group are 492.7 ± 2.9 Ma (MSWD = 0.53) and 488.9 ± 3.1 Ma (MSWD = 0.92), respectively. The age of quartz diorite that intrudes the Bainaimiao Group is 459.3 ± 6.4 Ma (MSWD = 2.20). Molybdenite samples from massive Cu-Mo-bearing ores and quartz veins in the southern ore belt yield a Re-Os isochron age of 438.2 ± 2.7 Ma (MSWD = 0.16), which is consistent with the Re-Os isochron age of molybdenite in the northern ore belt, implying that the two ore belts belong to the same mineralization system. Muscovite from a post-magmatic Cu-Mo-bearing quartz-calcite vein yields an Ar-Ar isochron age of 422.5 ± 3.9 Ma (MSWD = 0.64) with an initial 40Ar/36Ar ratio of 286 ± 21. The well-defined plateau age of the muscovite is 422.4 ± 2.6 Ma (MSWD = 0.05), which represents the time of the post-magmatic orogenic transformation event. Based on our new age data and previous findings, we propose that the Bainaimiao Cu-Mo-Au deposit formed in an active continental margin setting and experienced four stages of ore mineralization: (1) a Late Cambrian-Middle Ordovician volcanic-sedimentary stage; (2) a Late Ordovician porphyry mineralization stage; (3) a Late Silurian regional metamorphism stage; and (4) an orogenic transformation stage. Subhedral and euhedral Paleoproterozoic (2402-1810 Ma) inherited zircons indicate that the Bainaimiao Group has a tectonic affinity with the North China Craton. The Central Asian Orogenic Belt, which is closely related to the complex closure of the Paleo-Asian Ocean, is favorable for prospecting for Paleozoic porphyry Cu

Measurement of K 0 S and K *0 in p+p, d+Au, and Cu+Cu collisions at sqrt S NN = 200 GeV

DOE PAGES

Adare, A.; Aidala, C.

2014-11-01

The PHENIX experiment at the Relativistic Heavy Ion Collider has performed a systematic study of K 0 S and K *0 meson production at midrapidity in p+p, d+Au, and Cu+Cu collisions at sqrt S NN = 200 GeV. The K 0 S and K *0 mesons are reconstructed via their K 0 S and π 0(→γγ)π 0 (→γγ) and K *0 → K ± π ± decay modes, respectively. The measured transverse-momentum spectra are used to determine the nuclear modification factor of K 0 S and K *0 mesons in d+Au and Cu+Cu collisions at different centralities. In the d+Aumore » collisions, the nuclear modification factor of K 0 S and K *0 mesons is almost constant as a function of transverse momentum and is consistent with unity showing that cold-nuclear-matter effects do not play a significant role in the measured kinematic range. In Cu+Cu collisions, within the uncertainties no nuclear modification is registered in peripheral collisions. In central collisions, both mesons show suppression relative to the expectations from the p+p yield scaled by the number of binary nucleon-nucleon collisions in the Cu+Cu system. In the p T range 2–5 GeV/c, the strange mesons ( K 0 S, K *0) similarly to the Φ meson with hidden strangeness, show an intermediate suppression between the more suppressed light quark mesons (π 0) and the nonsuppressed baryons (p, p-bar). At higher transverse momentum, p T > 5 GeV/c, production of all particles is similarly suppressed by a factor of ≈2. (auth)« less

Interaction of SO2 with Cu/TiC(001) and Au/TiC(001): Towards a New Family of DeSOx Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodriguez, J.A.; Feria, L.; Jirsak, T.

2011-04-25

Experiments carried out under well-controlled conditions and density functional theory (DFT)-based calculations evidence that Cu and Au nanoparticles supported on a TiC(0 0 1) surface are quite active for the dissociation of the SO{sub 2} molecule. The Cu/TiC(0 0 1) and Au/TiC(0 0 1) systems cleave both S-O bonds of SO{sub 2} at a temperature of 150 K, displaying a reactivity much larger than that of TiC(0 0 1) or extended surfaces of bulk copper and gold. The origin of the high activity of the Cu/TiC(0 0 1) and Au/TiC(0 0 1) systems lies on the interaction between the Cmore » atoms of the substrate and the metal atoms of the supported particle, which results in a large polarization of its electron density. Experiments and theory consistently indicate that the Cu/TiC system is more active toward SO{sub 2} dissociation than the Au/TiC system. This type of systems may provide alternative and efficient DeSO{sub x} catalysts.« less

Effect of impurities on the mechanical and electronic properties of Au, Ag, and Cu monatomic chain nanowires

NASA Astrophysics Data System (ADS)

Çakır, D.; Gülseren, O.

2011-08-01

In this study, we have investigated the interaction of various different atomic and molecular species (H, C, O, H2, and O2) with the monatomic chains of Au, Ag, and Cu via total-energy calculations using the plane-wave pseudopotential method based on density functional theory. The stability, energetics, mechanical, and electronic properties of the clean and contaminated Au, Ag, and Cu nanowires have been presented. We have observed that the interaction of H, C, or O atoms with the monatomic chains are much stronger than the one of H2 or O2 molecules. The atomic impurities can easily be incorporated into these nanowires; they form stable and strong bonds with these one-dimensional structures when they are inserted in or placed close to the nanowires. Moreover, the metal-atomic impurity bond is much stronger than the metal-metal bond. Upon elongation, the nanowires contaminated with atomic impurities usually break from the remote metal-metal bond. We have observed both metallic and semiconducting contaminated nanowires depending on the type of impurity, whereas all clean monatomic chains of Au, Cu, and Ag exhibit metallic behavior. Our findings indicate that the stability and the electronic properties of these monatomic chains can be tuned by using appropriate molecular or atomic additives.

Krasnotur'insk Skarn copper ore field, Northern Urals: The U-Pb age of ore-controlling diorites and their place in the regional metallogeny

NASA Astrophysics Data System (ADS)

Grabezhev, A. I.; Ronkin, Yu. L.; Puchkov, V. N.; Gerdes, A.; Rovnushkin, M. Yu.

2014-06-01

The Krasnotur'insk skarn copper ore field known from the theoretical works of Academician K.S. Korzhinskii is located in the western part of the Tagil volcanic zone (in the area of the town of Krasnotur'insk). The ore field is composed of layered Devonian (Emsian) volcanosedimentary rocks intruded by small plutons of quartz diorites, diorites, and gabbrodiorites. Widespread pre-ore and intra-ore dikes of similar composition control the abundance of the andradite skarns formed after limestones and the magnetitesulfide and sulfide ore bodies formed after skarns. The LA-ICP-MS U-Pb concordant age of zircon from the quartz diorite of the Vasil'evsko-Moskalevskii pluton calculated by 16 analyses (16 crystals) is 407.7 ± 1.6 Ma (MSWD = 1.5). Taking into account the geological and petrogeochemical similarity of diorites of small plutons and intra-ore dikes, it is assumed that this age corresponds to the period of formation of the ore-magmatic system of the Krasnotur'insk skarn copper ore field. It was probably formed somewhat earlier than the Auerbakh montzonitic pluton and the accompanying skarn magnetite deposits in the south.

Copper isotopic zonation in the Northparkes porphyry Cu-Au deposit, SE Australia

NASA Astrophysics Data System (ADS)

Li, Weiqiang; Jackson, Simon E.; Pearson, Norman J.; Graham, Stuart

2010-07-01

Significant, systematic Cu isotopic variations have been found in the Northparkes porphyry Cu-Au deposit, NSW, Australia, which is an orthomagmatic porphyry Cu deposit. Copper isotope ratios have been measured in sulfide minerals (chalcopyrite and bornite) by both solution and laser ablation multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). The results from both methods show a variation in δ 65Cu of hypogene sulfide minerals of greater than 1‰ (relative to NIST976). Significantly, the results from four drill holes through two separate ore bodies show strikingly similar patterns of Cu isotope variation. The patterns are characterized by a sharp down-hole decrease from up to 0.8‰ (0.29 ± 0.56‰, 1 σ, n = 20) in the low-grade peripheral alteration zones (phyllic-propylitic alteration zone) to a low of ˜-0.4‰ (-0.25 ± 0.36‰, 1 σ, n = 30) at the margins of the most mineralized zones (Cu grade >1 wt%). In the high-grade cores of the systems, the compositions are more consistent at around 0.2‰ (0.19 ± 0.14‰, 1 σ, n = 40). The Cu isotopic zonation may be explained by isotope fractionation of Cu between vapor, solution and sulfides at high temperature, during boiling and sulfide precipitation processes. Sulfur isotopes also show an isotopically light shell at the margins of the high-grade ore zones, but these are displaced from the low δ 65Cu shells, such that there is no correlation between the Cu and S isotope signatures. Fe isotope data do not show any discernable variation along the drill core. This work demonstrates that Cu isotopes show a large response to high-temperature porphyry mineralizing processes, and that they may act as a vector to buried mineralization.

Chemical trend of superconducting transition temperature in hole-doped delafossite of CuAlO2, AgAlO2 and AuAlO2

NASA Astrophysics Data System (ADS)

Nakanishi, Akitaka; Katayama-Yoshida, Hiroshi

2012-12-01

We have performed the first-principles calculations about the superconducting transition temperature Tc of hole-doped delafossite CuAlO2, AgAlO2 and AuAlO2. Calculated Tc are about 50 K (CuAlO2), 40 K (AgAlO2) and 3 K(AuAlO2) at maximum in the optimum hole-doping concentration. The low Tc of AuAlO2 is attributed to the weak electron-phonon interaction caused by the low covalency and heavy atomic mass.

Melt recharge, f O2-T conditions, and metal fertility of felsic magmas: zircon trace element chemistry of Cu-Au porphyries in the Sanjiang orogenic belt, southwest China

NASA Astrophysics Data System (ADS)

Meng, Xuyang; Mao, Jingwen; Zhang, Changqing; Zhang, Dongyang; Liu, Huan

2018-06-01

The magmatic hydrothermal Pulang Cu deposit (Triassic) and the Beiya Au-Cu deposits (Eocene) are located in the Sanjiang copper porphyry belt, southwest China. Zircon chemistry was used to constrain the magmatic evolution and oxidation state of the porphyries. The results show that porphyries of the Beiya district formed from an early oxidized melt and a later relatively reduced and more evolved magma, whereas Pulang experienced a normal Cu porphyry evolutionary trend. The Pulang porphyries crystallized from more oxidized magma (ΔFMQ + 2.9-4.6, average = 4.0 ± 1.0, n = 3) with an average temperature of 709 ± 6 °C compared to the Beiya porphyries (ΔFMQ + 0.6-3.5, average = 1.9 ± 1.3, n = 5) with a mean magmatic temperature of 780 ± 22 °C. These data, combined with data from other Cu- and Au-rich porphyries in the Sanjiang belt (i.e., Machangjing Cu, Yao'an Au), are consistent with previous experimental work showing that elevated Cu and Au solubilities in magma require oxidizing conditions. A compilation of existing geochemical data for magmatic zircons from fertile and barren porphyry systems worldwide establishes an optimal diagnostic interval on CeIV/CeIII-TTi-in-zircon and (Eu/Eu*)N plots for generating magmatic hydrothermal Cu-Au deposits.

Bulk Properties of Ni3Al(gamma') With Cu and Au Additions

NASA Technical Reports Server (NTRS)

Bozzolo, Guillermo; Ferrante, John

1995-01-01

The BFS method for alloys is applied to the study of 200 alloys obtained from adding Cu and Au impurities to a Ni3Al matrix. We analyze the trends in the bulk properties of these alloys (heat of formation, lattice parameter, and bulk modulus) and detect specific alloy compositions for which these quantities have particular values. A detailed analysis of the atomic interactions that lead to the preferred ordering patterns is presented.

Highly monodisperse multiple twinned AuCu-Pt trimetallic nanoparticles with high index surfaces.

PubMed

Khanal, Subarna; Bhattarai, Nabraj; McMaster, David; Bahena, Daniel; Velazquez-Salazar, J Jesus; Jose-Yacaman, Miguel

2014-08-14

Trimetallic nanoparticles possess different properties than their mono- and bi-metallic counterparts, opening a wide range of possibilities for diverse potential applications with the notion to study possible morphology, atomic ordering, reduce precious metal consumption and many others. In this paper, we present a comprehensive experimental study on AuCu-Pt trimetallic nanoparticles with an average diameter of 15 ± 1.0 nm, synthesized in a one-pot synthesis method and characterized by the Cs-corrected scanning transmission electron microscopy technique that allowed us to probe the structure at the atomic level resolution. A new way to control the nanoparticle morphology by the presence of third metal (Pt) is also discussed by the overgrowth of Pt on the as prepared AuCu core by Frank-van der Merwe (FM) layer-by-layer and Stranski-Krastanov (SK) island-on-wetting-layer growth modes. With the application of this research, we are now a step closer to produce optimum catalysts in which the active phase forms only surface monolayers. In addition, the nanoalloy exhibits high index facet surfaces with {211} and {321} families that are highly open-structure surfaces and are interesting for the catalytic applications.

Highly Monodisperse Multiple Twinned AuCu/Pt Trimetallic Nanoparticles with High Index Surfaces

PubMed Central

Khanal, Subarna; Bhattarai, Nabraj; McMaster, David; Bahena, Daniel; Velazquez-Salazar, J. Jesus

2014-01-01

Trimetallic nanoparticles present different properties than their mono- and bi-metallic counterparts, opening a wide range of possibilities for diverse potential applications with the notion to study possible morphology, atomic ordering, reduce precious metal consumption and many others. In this paper, we are presenting a comprehensive experimental study on AuCu/Pt trimetallic nanoparticles with an average diameter 15 ± 1.0 nm, synthesized in one-pot synthesis method and characterized by Cs-corrected scanning transmission electron microscopy technique that allowed us to probe the structure at the atomic level resolution. A new way to control the nanoparticle morphology by the presence of third metal (Pt) is also discussed by the overgrowth of Pt on as prepared AuCu core by Frank–van der Merwe (FM) layer-by-layer and Stranski–Krastanov (SK) island-on-wetting-layer growth modes. With the application of this research, we are now a step closer to produce optimum catalysts in which the active phase forms only surface monolayers. In addition, the nanoalloy presents high index facet surfaces with {211} and {321} families, that are highly open-structure surfaces and are interesting for the catalytic applications. PMID:24975090

Colorimetric determination of glutathione in human serum and cell lines by exploiting the peroxidase-like activity of CuS-polydopamine-Au composite.

PubMed

Wang, Yanying; Liu, Yaqin; Ding, Fang; Zhu, Xiaoyan; Yang, Li; Zou, Ping; Rao, Hanbing; Zhao, Qingbiao; Wang, Xianxiang

2018-06-07

In this study, we developed a simple colorimetric approach to detect glutathione (GSH). The proposed approach is based on the ability of CuS-PDA-Au composite material to catalytically oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to ox-TMB to induce a blue color with an absorption peak centered at 652 nm. However, the introduction of GSH can result in a decrease in oxidized TMB; similarly, it can combine with Au nanoparticles (Au NPs) on the surface of CuS-PDA-Au composite material. Both approaches can result in a fading blue color and a reduction of the absorbance at 652 nm. Based on this above, we proposed a technique to detect GSH quantitatively and qualitatively through UV-Vis spectroscopy and naked eye, respectively. This approach demonstrates a low detection limit of 0.42 μM with a broad detection range of 5 × 10 -7 -1 × 10 -4  M with the assistance of UV-Vis spectroscopy. More importantly, this approach is convenient and rapid. This method was successfully applied to GSH detection in human serum and cell lines. Graphical abstract A colorimetric approach has been developed by exploiting the peroxidase-like activity of CuS-polydopamine-Au composite for sensitive glutathione detection.

Magmatic controls on the genesis of porphyry Cu-Mo-Au deposits: The Bingham Canyon example

NASA Astrophysics Data System (ADS)

Grondahl, Carter; Zajacz, Zoltán

2017-12-01

Bingham Canyon is one of the world's largest porphyry Cu-Mo-Au deposits and was previously used as an example to emphasize the role of magma mixing and magmatic sulphide saturation in the enhancement of ore fertility of magmatic systems. We analyzed whole rocks, minerals, and silicate melt inclusions (SMI) from the co-genetic, ore-contemporaneous volcanic package (∼38 Ma). As opposed to previous propositions, whole-rock trace element signatures preclude shoshonite-latite genesis via mixing of melanephelinite and trachyte or rhyolite, whereas core to rim compositional profiles of large clinopyroxene phenocrysts suggests the amalgamation of the ore-related magma reservoir by episodic recharge of shoshonitic to latitic magmas with various degrees of differentiation. Major and trace element and Sr and Nd isotopic signatures indicate that the ore-related shoshonite-latite series were generated by low-degree partial melting of an ancient metasomatized mantle source yielding volatile and ore metal rich magmas. Latite and SMI compositions can be reproduced by MELTS modeling assuming 2-step lower and upper crustal fractionation of a primary shoshonite with minimal country rock assimilation. High oxygen fugacities (≈ NNO + 1) are prevalent as evidenced by olivine-spinel oxybarometry, high SO3 in apatite, and anhydrite saturation. The magma could therefore carry significantly more S than would have been possible at more reducing conditions, and the extent of ore metal sequestration by magmatic sulphide saturation was minimal. The SMI data show that the latites were Cu rich, with Cu concentrations in the silicate melt reaching up to 300-400 ppm at about 60 wt% SiO2. The Au and Ag concentrations are also high (1.5-4 and 50-200 ppb, respectively), but show less variation with SiO2. A sudden drop in Cu and S concentrations in the silicate melt at around 65 wt% SiO2 in the presence of high Cl, Mo, Ag, and Au shows that the onset of effective metal extraction by fluid

Femtosecond Laser Fabricated Ag@Au and Cu@Au Alloy Nanoparticles for Surface Enhaned Raman Spectrosocpy Based Trace Explosives Detection

NASA Astrophysics Data System (ADS)

Sree Satya Bharati, Moram; Byram, Chandu; Soma, Venugopal R.

2018-03-01

Herein we present results from our detailed studies on the fabrication of Ag@Au and Cu@Au alloy nanoparticles (NPs) using the femtosecond laser ablation in liquid technique. The NPs were obtained by ablating the pure Ag, Cu targets (bulk) in HAuCl4 (5 mM) solution. The absorption properties of the obtained NPs colloids were characterized using UV-Visible absorption spectrometer and their size, shape, and crystallinity were investigated using the XRD, FESEM and TEM techniques. The fabricated NPs were utilized for sensing of explosive molecules such as 2, 4, 6-trinitrophenol (PA), 2, 4-dinitrotoluene (DNT) and a common dye methylene blue (MB) using the surface enhanced Raman spectroscopy (SERS) technique. The detection limit in terms of weight was as low as few nano-grams in the case of nitroaromatic explosive compounds (PA, DNT) and few picograms in the case of a common dye molecule (MB). Typical enhancement factors achieved were estimated to be 104, 105 and 107, respectively, for PA, DNT, and MB. The significance of the present work lies in exploring the performance of the prepared NPs being used as SERS substrates for explosives detection using a portable Raman instrument. Such capability enables one to carry the spectrometer to the point of interest in the field and evaluate any hazardous samples within a short period of time.

Iron and chlorine as guides to stratiform Cu-Co-Au deposits, Idaho Cobalt Belt, USA

USGS Publications Warehouse

Nash, J.T.; Connor, J.J.

1993-01-01

The Cu-Co-Au deposits of the Idaho Cobalt Belt are in lithostratigraphic zones of the Middle Proterozoic Yellowjacket Formation characterized by distinctive chemical and mineralogical compositions including high concentrations of Fe (15- > 30 wt. percent Fe2O3), Cl (0.1-1.10 wt. percent), and magnetite or biotite (> 50 vol. percent). The Cu-Co-Au deposits of the Blackbird mine are stratabound in Fe-silicate facies rocks that are rich in biotite, Fe, and Cl, but stratigraphically equivalent rocks farther than 10 km from ore deposits have similar compositions. A lower lithostratigraphic zone containing magnetite and small Cu-Co-Au deposits extends for more than 40 km. The Fe-rich strata are probably exhalative units related to mafic volcanism and submarine hot springs, but the origin of the high Cl concentrations is less clear. Former chlorine-rich pore fluids are suggested by the presence of supersaline fluid inclusions, by Cl-rich biotite and scapolite (as much as 1.87 percent Cl in Fe-rich biotite), and by high Cl concentrations in rock samples. Chlorine is enriched in specific strata and in zones characterized by soft-sediment deformation, thus probably was introduced during sedimentation or diagenesis. Unlike some metasedimentary rocks containing scapolite and high Cl, the Yellowjacket Formation lacks evidence for evaporitic strata that could have been a source of Cl. More likely, the Cl reflects a submarine brine that carried Fe, K, and base metals. Strata containing anomalous Fe-K-Cl are considered to be a guide to sub-basins favorable for the occurrence of stratiform base-metal deposits. ?? 1993 Springer-Verlag.

Quantum tunneling in real space: Tautomerization of single porphycene molecules on the (111) surface of Cu, Ag, and Au.

PubMed

Kumagai, Takashi; Ladenthin, Janina N; Litman, Yair; Rossi, Mariana; Grill, Leonhard; Gawinkowski, Sylwester; Waluk, Jacek; Persson, Mats

2018-03-14

Tautomerization in single porphycene molecules is investigated on Cu(111), Ag(111), and Au(111) surfaces by a combination of low-temperature scanning tunneling microscopy (STM) experiments and density functional theory (DFT) calculations. It is revealed that the trans configuration is the thermodynamically stable form of porphycene on Cu(111) and Ag(111), whereas the cis configuration occurs as a meta-stable form. The trans → cis or cis → trans conversion on Cu(111) can be induced in an unidirectional fashion by injecting tunneling electrons from the STM tip or heating the surface, respectively. We find that the cis ↔ cis tautomerization on Cu(111) occurs spontaneously via tunneling, verified by the negligible temperature dependence of the tautomerization rate below ∼23 K. Van der Waals corrected DFT calculations are used to characterize the adsorption structures of porphycene and to map the potential energy surface of the tautomerization on Cu(111). The calculated barriers are too high to be thermally overcome at cryogenic temperatures used in the experiment and zero-point energy corrections do not change this picture, leaving tunneling as the most likely mechanism. On Ag(111), the reversible trans ↔ cis conversion occurs spontaneously at 5 K and the cis ↔ cis tautomerization rate is much higher than on Cu(111), indicating a significantly smaller tautomerization barrier on Ag(111) due to the weaker interaction between porphycene and the surface compared to Cu(111). Additionally, the STM experiments and DFT calculations reveal that tautomerization on Cu(111) and Ag(111) occurs with migration of porphycene along the surface; thus, the translational motion couples with the tautomerization coordinate. On the other hand, the trans and cis configurations are not discernible in the STM image and no tautomerization is observed for porphycene on Au(111). The weak interaction of porphycene with Au(111) is closest to the gas-phase limit and therefore the absence

Quantum tunneling in real space: Tautomerization of single porphycene molecules on the (111) surface of Cu, Ag, and Au

NASA Astrophysics Data System (ADS)

Kumagai, Takashi; Ladenthin, Janina N.; Litman, Yair; Rossi, Mariana; Grill, Leonhard; Gawinkowski, Sylwester; Waluk, Jacek; Persson, Mats

2018-03-01

Tautomerization in single porphycene molecules is investigated on Cu(111), Ag(111), and Au(111) surfaces by a combination of low-temperature scanning tunneling microscopy (STM) experiments and density functional theory (DFT) calculations. It is revealed that the trans configuration is the thermodynamically stable form of porphycene on Cu(111) and Ag(111), whereas the cis configuration occurs as a meta-stable form. The trans → cis or cis → trans conversion on Cu(111) can be induced in an unidirectional fashion by injecting tunneling electrons from the STM tip or heating the surface, respectively. We find that the cis ↔ cis tautomerization on Cu(111) occurs spontaneously via tunneling, verified by the negligible temperature dependence of the tautomerization rate below ˜23 K. Van der Waals corrected DFT calculations are used to characterize the adsorption structures of porphycene and to map the potential energy surface of the tautomerization on Cu(111). The calculated barriers are too high to be thermally overcome at cryogenic temperatures used in the experiment and zero-point energy corrections do not change this picture, leaving tunneling as the most likely mechanism. On Ag(111), the reversible trans ↔ cis conversion occurs spontaneously at 5 K and the cis ↔ cis tautomerization rate is much higher than on Cu(111), indicating a significantly smaller tautomerization barrier on Ag(111) due to the weaker interaction between porphycene and the surface compared to Cu(111). Additionally, the STM experiments and DFT calculations reveal that tautomerization on Cu(111) and Ag(111) occurs with migration of porphycene along the surface; thus, the translational motion couples with the tautomerization coordinate. On the other hand, the trans and cis configurations are not discernible in the STM image and no tautomerization is observed for porphycene on Au(111). The weak interaction of porphycene with Au(111) is closest to the gas-phase limit and therefore the absence

X-ray fluorescence holography studies for a Cu3Au crystal

NASA Astrophysics Data System (ADS)

Dąbrowski, K. M.; Dul, D. T.; Jaworska-Gołąb, T.; Rysz, J.; Korecki, P.

2015-12-01

In this work we show that performing a numerical correction for beam attenuation and indirect excitation allows one to fully restore element sensitivity in the three-dimensional reconstruction of the atomic structure. This is exemplified by a comparison of atomic images reconstructed from holograms measured for ordered and disordered phases of a Cu3Au crystal that clearly show sensitivity to changes in occupancy of the atomic sites. Moreover, the numerical correction, which is based on quantitative methods of X-ray fluorescence spectroscopy, was extended to take into account the influence of a disturbed overlayer in the sample.

Interaction of SO2 with Cu/TiC(0 0 1) and Au/TiC(0 0 1): Toward a New Family of DeSOx Catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

L Feria; J Rodriguez; T Jirsak

2011-12-31

Experiments carried out under well-controlled conditions and density functional theory (DFT)-based calculations evidence that Cu and Au nanoparticles supported on a TiC(0 0 1) surface are quite active for the dissociation of the SO{sub 2} molecule. The Cu/TiC(0 0 1) and Au/TiC(0 0 1) systems cleave both S-O bonds of SO{sub 2} at a temperature of 150 K, displaying a reactivity much larger than that of TiC(0 0 1) or extended surfaces of bulk copper and gold. The origin of the high activity of the Cu/TiC(0 0 1) and Au/TiC(0 0 1) systems lies on the interaction between the Cmore » atoms of the substrate and the metal atoms of the supported particle, which results in a large polarization of its electron density. Experiments and theory consistently indicate that the Cu/TiC system is more active toward SO{sub 2} dissociation than the Au/TiC system. This type of systems may provide alternative and efficient DeSO{sub x} catalysts.« less

Study of the effects of MeV Ag, Cu, Au, and Sn implantation on the optical properties of LiNbO3

NASA Technical Reports Server (NTRS)

Williams, E. K.; Ila, D.; Sarkisov, S.; Curley, M.; Poker, D. B.; Hensley, D. K.; Borel, C.

1998-01-01

The authors present the results of characterization of linear absorption and nonlinear refractive index of Au, Ag, Cu and Sn ion implantation into LiNbO3. Ag was implanted at 1.5 MeV to fluences of 2 to 17 x 17(exp 16)/sq cm at room temperature. Au and Cu were implanted to fluences of 5 to 20 x 10(exp 16)/sq cm at an energy of 2.0 MeV. Sn was implanted to a fluence of 1.6 x 10(exp 17)/sq cm at 160 kV. Optical absorption spectrometry indicated an absorption peak for the Au implanted samples after heat treatment at 1,000 C at approx. 620 nm. The Ag implanted samples absorption peaks shifted from approx. 450 nm before heat treatment to 550 nm after 500 C for 1h. Heat treatment at 800 C returned the Ag implanted crystals to a clear state. Cu nanocluster absorption peaks disappears at 500 C. No Sn clusters were observed by optical absorption or XRD. The size of the Ag and Au clusters as a function of heat treatment were determined from the absorption peaks. The Ag clusters did not change appreciably in size with heat treatment. The Au clusters increased from 3 to 9 nm diameter upon heat treatment at 1000 C. TEM analysis performed on a Au implanted crystal indicated the formation of Au nanocrystals with facets normal to the c-axis. Measurements of the nonlinear refractive indices were carried out using the Z-scan method with a tunable dye laser pumped by a frequency doubled mode-locked Nd:YAG laser. The dye laser had a 4.5 ps pulse duration time and 76 MHz pulse repetition rate (575 nm).

U-Pb (zircon) and geochemical constraints on the age, origin, and evolution of Paleozoic arc magmas in the Oyu Tolgoi porphyry Cu-Au district, southern Mongolia

USGS Publications Warehouse

Wainwright, A.J.; Tosdal, R.M.; Wooden, J.L.; Mazdab, F.K.; Friedman, R.M.

2011-01-01

Uranium-Pb (zircon) ages are linked with geochemical data for porphyry intrusions associated with giant porphyry Cu-Au systems at Oyu Tolgoi to place those rocks within the petrochemical framework of Devonian and Carboniferous rocks of southern Mongolia. In this part of the Gurvansayhan terrane within the Central Asian Orogenic Belt, the transition from Devonian tholeiitic marine rocks to unconformably overlying Carboniferous calc-alkaline subaerial to shallow marine volcanic rocks reflects volcanic arc thickening and maturation. Radiogenic Nd and Pb isotopic compositions (??Nd(t) range from +3.1 to +7.5 and 206Pb/204Pb values for feldspars range from 17.97 to 18.72), as well as low high-field strength element (HFSE) contents of most rocks (mafic rocks typically have <1.5% TiO2) are consistent with magma derivation from depleted mantle in an intra-oceanic volcanic arc. The Late Devonian and Carboniferous felsic rocks are dominantly medium- to high-K calc-alkaline and characterized by a decrease in Sr/Y ratios through time, with the Carboniferous rocks being more felsic than those of Devonian age. Porphyry Cu-Au related intrusions were emplaced in the Late Devonian during the transition from tholeiitic to calc-alkaline arc magmatism. Uranium-Pb (zircon) geochronology indicates that the Late Devonian pre- to syn-mineral quartz monzodiorite intrusions associated with the porphyry Cu-Au deposits are ~372Ma, whereas granodiorite intrusions that post-date major shortening and are associated with less well-developed porphyry Cu-Au mineralization are ~366Ma. Trace element geochemistry of zircons in the Late Devonian intrusions associated with the porphyry Cu-Au systems contain distinct Th/U and Yb/Gd ratios, as well as Hf and Y concentrations that reflect mixing of magma of distinct compositions. These characteristics are missing in the unmineralized Carboniferous intrusions. High Sr/Y and evidence for magma mixing in syn- to late-mineral intrusions distinguish the Late

Crystal nucleation in amorphous (Au/100-y/Cu/y/)77Si9Ge14 alloys

NASA Technical Reports Server (NTRS)

Thompson, C. V.; Greer, A. L.; Spaepen, F.

1983-01-01

Because, unlike most metallic glasses, melt-spun alloys of the series (Au/100-y/Cu/y/)77Si9Ge14 exhibit well separated glass transition and kinetic crystallization temperatures, crystallization can be studied in the fully relaxed amorphous phase. An isothermal calorimetric analysis of the devitrification kinetics of the amorphous alloy indicates sporadic nucleation and a constant growth rate. It is found for the cases of alloys with y values lower than 25 that the classical theory of homogeneous nucleation is consistent with observations, including transient effects. An analysis of the crystallization kinetics shows that slow crystal growth rates play an important role in glass formation in these alloys. Although the reduced glass transition temperature increases with Cu content, glass formation is more difficult at high Cu contents, perhaps because of a difference in nucleus composition.

Slicing-independent RISC activation requires the argonaute PAZ domain.

PubMed

Gu, Shuo; Jin, Lan; Huang, Yong; Zhang, Feijie; Kay, Mark A

2012-08-21

Small RNAs regulate genetic networks through a ribonucleoprotein complex called the RNA-induced silencing complex (RISC), which, in mammals, contains at its center one of four Argonaute proteins (Ago1-Ago4). A key regulatory event in the RNA interference (RNAi) and microRNA (miRNA) pathways is Ago loading, wherein double-stranded small-RNA duplexes are incorporated into RISC (pre-RISC) and then become single-stranded (mature RISC), a process that is not well understood. The Agos contain an evolutionarily conserved PAZ (Piwi/Argonaute/Zwille) domain whose primary function is to bind the 3' end of small RNAs. We created multiple PAZ-domain-disrupted mutant Ago proteins and studied their biochemical properties and biological functionality in cells. We found that the PAZ domain is dispensable for Ago loading of slicing-competent RISC. In contrast, in the absence of slicer activity or slicer-substrate duplex RNAs, PAZ-disrupted Agos bound duplex small interfering RNAs, but were unable to unwind or eject the passenger strand and form functional RISC complexes. We have discovered that the highly conserved PAZ domain plays an important role in RISC activation, providing new mechanistic insights into how miRNAs regulate genes, as well as new insights for future design of miRNA- and RNAi-based therapeutics. Copyright © 2012 Elsevier Ltd. All rights reserved.

Trace Elements in the Marine Sediments of the La Paz Lagoon, Baja California Peninsula, Mexico: Pollution Status in 2013.

PubMed

Pérez-Tribouillier, Habacuc; Shumilin, Evgueni; Rodríguez-Figueroa, Griselda Margarita

2015-07-01

To determine the actual concentrations of trace elements in surface sediments from the La Paz Lagoon, as well as their associations and possible origins, 91 sediment samples were analyzed for more than 50 elements using a combination of ICP-MS and ICP-AES. The results of a principal component analysis are used to distinguish four associative groups within the elements. Natural enrichment of As, Cd and U occurs due to the supply of weathered phosphorites from the El Cien formation located to the north-west of the lagoon. Sediment quality indices for potentially toxic trace elements do not show any probable impact on the biota of the lagoon. Only the concentrations of As in 30 % of the stations and Cu in 20 % of them exceed related effect range low levels. The highest concentration of Pb (36.8 mg kg(-1)) was measured in the sediments near the City of La Paz.

UV-Vis-Induced Degradation of Phenol over Magnetic Photocatalysts Modified with Pt, Pd, Cu and Au Nanoparticles

PubMed Central

Wysocka, Izabela; Trzciński, Konrad; Łapiński, Marcin; Nowaczyk, Grzegorz; Zielińska-Jurek, Anna

2018-01-01

The combination of TiO2 photocatalyst and magnetic oxide nanoparticles enhances the separation and recoverable properties of nanosized TiO2 photocatalyst. Metal-modified (Me = Pd, Au, Pt, Cu) TiO2/SiO2@Fe3O4 nanocomposites were prepared by an ultrasonic-assisted sol-gel method. All prepared samples were characterized by X-ray powder diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), Mott-Schottky analysis and photoluminescence spectroscopy (PL). Phenol oxidation pathways of magnetic photocatalysts modified with Pt, Pd, Cu and Au nanoparticles proceeded by generation of reactive oxygen species, which oxidized phenol to benzoquinone, hydroquinone and catechol. Benzoquinone and maleic acid were products, which were determined in the hydroquinone oxidation pathway. The highest mineralization rate was observed for Pd-TiO2/SiO2@Fe3O4 and Cu-TiO2/SiO2@Fe3O4 photocatalysts, which produced the highest concentration of catechol during photocatalytic reaction. For Pt-TiO2/SiO2@Fe3O4 nanocomposite, a lack of catechol after 60 min of irradiation resulted in low mineralization rate (CO2 formation). It is proposed that the enhanced photocatalytic activity of palladium and copper-modified photocatalysts is related to an increase in the amount of adsorption sites and efficient charge carrier separation, whereas the keto-enol tautomeric equilibrium retards the rate of phenol photomineralization on Au-TiO2/SiO2@Fe3O4. The magnetization hysteresis loop indicated that the obtained hybrid photocatalyst showed magnetic properties and therefore could be easily separated after treatment process. PMID:29316667

Comparative study of post-growth annealing of Cu(hfac)2, Co2(CO)8 and Me2Au(acac) metal precursors deposited by FEBID.

PubMed

Puydinger Dos Santos, Marcos Vinicius; Szkudlarek, Aleksandra; Rydosz, Artur; Guerra-Nuñez, Carlos; Béron, Fanny; Pirota, Kleber Roberto; Moshkalev, Stanislav; Diniz, José Alexandre; Utke, Ivo

2018-01-01

Non-noble metals, such as Cu and Co, as well as noble metals, such as Au, can be used in a number modern technological applications, which include advanced scanning-probe systems, magnetic memory and storage, ferroelectric tunnel junction memristors, metal interconnects for high performance integrated circuits in microelectronics and nano-optics applications, especially in the areas of plasmonics and metamaterials. Focused-electron-beam-induced deposition (FEBID) is a maskless direct-write tool capable of defining 3-dimensional metal deposits at nanometre scale for above applications. However, codeposition of organic ligands when using organometallic precursors is a typical problem that limits FEBID of pure metal nanostructures. In this work, we present a comparative study using a post-growth annealing protocol at 100, 200, and 300 °C under high vacuum on deposits obtained from Co 2 (CO) 8 , Cu(II)(hfac) 2 , and Me 2 Au(acac) to study improvements on composition and electrical conductivity. Although the as-deposited material was similar for all precursors, metal grains embedded in a carbonaceous matrix, the post-growth annealing results differed. Cu-containing deposits showed the formation of pure Cu nanocrystals at the outer surface of the initial deposit for temperatures above 100 °C, due to the migration of Cu atoms from the carbonaceous matrix containing carbon, oxygen, and fluorine atoms. The average size of the Cu crystals doubles between 100 and 300 °C of annealing temperature, while the composition remains constant. In contrast, for Co-containing deposits oxygen release was observed upon annealing, while the carbon content remained approximately constant; the cobalt atoms coalesced to form a metallic film. The as-deposited Au-containing material shows subnanometric grains that coalesce at 100 °C, maintaining the same average size at annealing temperatures up to 300 °C. Raman analysis suggests that the amorphous carbonaceous matrix of the as-written Co

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 liquidmore » 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.« less

The origin of Cu/Au ratios in porphyry-type ore deposits.

PubMed

Halter, Werner E; Pettke, Thomas; Heinrich, Christoph A

2002-06-07

Microanalysis of major and trace elements in sulfide and silicate melt inclusions by laser-ablation inductively coupled plasma mass spectrometry indicates a direct link between a magmatic sulfide liquid and the composition of porphyry-type ore deposits. Copper (Cu), gold (Au), and iron (Fe) are first concentrated in a sulfide melt during magmatic evolution and then released to an ore-forming hydrothermal fluid exsolved late in the history of a magma chamber. The composition of sulfide liquids depends on the initial composition and source of the magma, but it also changes during the evolution of the magma in the crust. Magmatic sulfide melts may exert the dominant direct control on the economic metal ratios of porphyry-type ore deposits.

Stable isotope studies of metasomatic Ca-Fe-Al-Si skarns and associated metamorphic and igneous rocks, Osgood Mountains, Nevada

USGS Publications Warehouse

Taylor, B.E.; O'Neil, J.R.

1977-01-01

Garnet-pyroxene skarns were formed 90 m.y. B.P. in the Osgood Mountains at or near contacts of grandiorite with calcareous rocks of the Cambrian Preble Formation. The metasomatic replacement followed contact metamorphic recrystallization of the Preble. The sources, temperature, and variation in H2O/CO2 ratios of the metasomatic fluid are interpreted from 269 analyses of oxygen, carbon, hydrogen, and sulfur isotopes in whole rocks, minerals and inclusion fluids. Skarns formed in three mineralogical stages. Oxygen isotope data indicate that temperatures during the crystallization of garnet, pyroxene and wollastonite (Stage I) were least 550 ?? C, and that the metasomatic fluid had an {Mathematical expression} ??? 0.035 in the massive skarns, and ??? 0.12 in vein skarns up to 3 cm thick. Pore fluids in isotopic equilibrium with garnet in calc-silicate metamorphic rocks, on the other hand, had {Mathematical expression} ??? 0.15. The metasomatic fluids of Stage I were derived primarily from the crystallizing magma. The isotopic composition of magmatic water was ??18O =+9.0, ??D= -30 to -45. Oxygen isotope temperatures of greater than 620 ?? C were determined for the granodiorite. Isotopic and chemical equilibria between mineral surfaces and the metasomatic fluid were approached simultaneously in parts of the skarn several meters or more apart, while isotopic and chemical disequilibria (i.e. zoning) have been preserved between 20 to 40 ??m-thick zones in grandite garnet. More Fe-, or andradite-rich garnet crystallized in more H2O-rich C-O-H fluids ( {Mathematical expression} ??? 0.01) than present with grossularite-rich garnet ( {Mathematical expression}??? 0.035). Stage II was marked by the replacement of garnet and pyroxene by quartz, amphibole, plagioclase, epidote, magnetite, and calcite. Many of the replacement reactions took place over a relatively narrow range in temperature (480-550 ?? C), as indicated by 18O fractionations between quartz and amphibole. Meteoric

Embedded atom method potential for studying mechanical properties of binary Cu–Au alloys

NASA Astrophysics Data System (ADS)

Gola, Adrien; Pastewka, Lars

2018-07-01

We present an embedded atom method (EAM) potential for the binary Cu–Au system. The unary phases are described by two well-tested unary EAM potentials for Cu and Au. We fitted the interaction between Cu and Au to experimental properties of the binary intermetallic phases Cu3Au, CuAu and CuAu3. Particular attention has been paid to reproducing stacking fault energies in order to obtain a potential suitable for studying deformation in this binary system. The resulting energies, lattice constant, elastic properties and melting points are in good agreement with available experimental data. We use nested sampling to show that our potential reproduces the phase boundaries between intermetallic phases and the disordered face-centered cubic solid solution. We benchmark our potential against four popular Cu–Au EAM parameterizations and density-functional theory calculations.

Cu(II)-Doped Polydopamine-Coated Gold Nanorods for Tumor Theranostics.

PubMed

Liu, Shuwei; Wang, Lu; Lin, Min; Wang, Dandan; Song, Ziqi; Li, Shuyao; Ge, Rui; Zhang, Xue; Liu, Yi; Li, Zhimin; Sun, Hongchen; Yang, Bai; Zhang, Hao

2017-12-27

Gold nanorods (AuNRs) are potentially useful in tumor theranostics, but the poor stability, high toxicity, and rapid removal by the immune system seriously limit their theranostic applications. In our study, we demonstrate the fabrication of Cu(II)-doped polydopamine-coated AuNR (AuNR@CuPDA), which significantly improves the potentials in tumor theranostics. Besides the improvement of physiological stability and biocompatibility, the PDA shell increases the photothermal performance and prolongs the blood circulation time of AuNRs. The half-life of AuNRs during blood circulation increases from 0.7 to 4.5 h after PDA coating, and the injected dose per gram of tumor tissue is 4.6% ID g -1 for AuNR@CuPDA. In addition to computer tomography imaging, the loading of Cu(II) in PDA shell endows AuNR@CuPDA with magnetic resonance imaging function. Cu(II) doped in PDA shell also exhibits chemotherapeutic behavior, and the tumor inhibitor rate is 31.2%. Further combining 808 nm laser-driven photothermal therapy, tumors were completely ablated, and no recurrence was observed. Liver and renal functions tests and histological analysis of major organs confirm that AuNR@CuPDA is in good safety.

Luminescent Copper(I) Halide Butterfly Dimers Coordinated to [Au(CH3imCH2py)2]BF4 and [Au(CH3imCH2quin)2]BF4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Catalano, V.; Moore, A; Shearer, J

2009-01-01

The coordination chemistry of copper(I) halides to the homoleptic, N-heterocyclic carbene Au(I) complexes [Au(CH{sub 3}imCH{sub 2}quin){sub 2}]BF{sub 4} and [Au(CH{sub 3}imCH{sub 2}py){sub 2}]BF{sub 4} was explored. The reaction of CuX (X = Cl, Br, I) with either [Au(CH{sub 3}imCH{sub 2}quin){sub 2}]BF{sub 4} or [Au(CH{sub 3}imCH{sub 2}py){sub 2}]BF{sub 4} produces trimetallic complexes containing Cu{sub 2}X{sub 2}-butterfly copper clusters coordinated to the two imine moieties. The triangular arrangement of the metals places the gold(I) center in close proximity ({approx}2.5-2.6 {angstrom}) to the centroid of the Cu-Cu vector. The Cu-Cu separations vary as a function of bridging halide with the shortest Cu-Cu separationsmore » of {approx}2.5 {angstrom} found in the iodo-complexes and the longest separations of 2.9 {angstrom} found in the bridging chloride complexes. In all six complexes the Au-Cu separations range from {approx}2.8 to 3.0 {angstrom}. In the absence of halides, the dimetallic complex [AuCu(CH{sub 3}imCH{sub 2}py){sub 2}(NCCH{sub 3}){sub 2}](BF{sub 4}){sub 2}, containing a long Au-Cu distance of {approx}4.72 {angstrom} is formed. Additionally, as the byproduct of the reaction of CuBr with [Au(CH{sub 3}imCH{sub 2}quin){sub 2}]BF{sub 4} the deep-red, dimetallic compound, AuCuBr{sub 2}(CH{sub 3}imCH{sub 2}quin){sub 2}, was isolated in very low yield. All of these complexes were studied by NMR spectroscopy, mass spectrometry, and the copper containing species were additionally characterized by X-ray crystallography. In solution the copper centers dissociate from the gold complexes, but as shown by XANES and EXAFS spectroscopy, at low temperature the Cu-Cu linkage is broken, and the individual copper(I) halides reposition themselves to opposite sides of the gold complex while remaining coordinated to one imine moiety. In the solid state all of the complexes are photoluminescent, though the nature of the excited state was not determined.« less

Elastic moduli of cast Ti-Au, Ti-Ag, and Ti-Cu alloys.

PubMed

Kikuchi, Masafumi; Takahashi, Masatoshi; Okuno, Osamu

2006-07-01

This study investigated the effect of alloying titanium with gold, silver, or copper on the elastic properties of the alloys. A series of binary titanium alloys was made with four concentrations of gold, silver, or copper (5, 10, 20, and 30 mass%) in an argon-arc melting furnace. The Young's moduli and Poisson's ratios of the alloy castings were determined with an ultrasonic-pulse method. The density of each alloy was previously measured by the Archimedes' principle. Results were analyzed using one-way ANOVA and the Scheffé's test. The densities of Ti-Au, Ti-Ag, and Ti-Cu alloys monotonically increased as the concentration of alloying elements increased. As the concentration of gold or silver increased to 20%, the Young's modulus significantly decreased, followed by a subsequent increase in value. As the concentration of copper increased, the Young's modulus monotonically increased. The Young's moduli of all the Ti-Cu alloys were significantly higher than that of the titanium. The density of all the experimental alloys was virtually independent of the alloy phases, while the Young's moduli and Poisson's ratios of the alloys were dependent. The addition of gold or silver slightly reduced the Young's modulus of the titanium when the alloy phase was single alpha. The increase in the Young's modulus of the Ti-Cu alloys is probably due to the precipitation of intermetallic compound Ti2Cu. Copper turned out to be a moderate stiffener that gains a Young's modulus of titanium up to 20% at the copper concentration of 30 mass%.

Nucleation and growth of order in Cu(3)Au (111) films

NASA Astrophysics Data System (ADS)

Bonham, Scott William

The present work epitaxial investigated two types of ordering phenomena using films of Cusb3Au, the order-disorder phase transition on the (111) crystal surface, and preferential selection of one of two possible stacking domains. Cusb3Au has long been a model system for studying order-disorder phase transition. Bulk material exhibits a discontinuous transition while the surfaces exhibit continuos transitions and the long-range order parameter S is proportional to (Tsb{c}-T)sp{beta}, where Tsb{c} is the critical temperature. The transition of the (111) surface is studied with qualitative reflection high-energy electron diffraction (RHEED), which is sensitive to only the first few atomic layers. This work significantly improves on an earlier study through both improved data collection and more comprehensive data analysis. The measured value of beta =0.50± 0.02 agrees with both the earlier measurements and with predictions of mean field theory. In addition, data on surface defects during the transition and on the kinetics of ordering are presented. During epitaxial growth of (111) face-centered cubic crystal films, such as disordered Cusb3Au, there are two possible ways that successive layers can be laid down, leading to two types of stacking domains. However, a small vicinal miscut (0.5sp° {-}1sp° ) of the crystal surface introduces step edges that change nucleation preferences of the domains, resulting in one being preferred over the other by ratios up to 700:1. Fifteen samples were measured and this preference has been found to depend systematically and strongly on the magnitude and direction of the sample miscut. A qualitative RHEED study confirms that a preference for one of the stacking senses is present after deposition of a few monlolayers of Cusb3Au. The observed behavior of the film can be explained by a model in which Cu and Au atoms minimize their number of Nb nearest neighbors when growing over the Nb step edges. This represents both a discovery of a

Changes in the adsorbate dipole layer with changing d-filling of the metal (II) (Co, Ni, Cu) phthalocyanines on Au(111).

PubMed

Xiao, Jie; Dowben, Peter A

2009-02-04

In combined photoemission and inverse photoemission spectroscopy studies, we observe changes in the metal phthalocyanine molecular orbital offsets with respect to the conducting gold substrate Fermi level, with the changing d-electron filling of the metal (II) (Co, Ni, Cu) phthalocyanines. The implication is that the interfacial dipole layer depends upon the choice of metal (Co, Ni, Cu) centers within the metal (II) phthalocyanines adsorbed on Au(111).

Genesis of the Bangbule Pb-Zn-Cu polymetallic deposit in Tibet, western China: Evidence from zircon U-Pb geochronology and S-Pb isotopes

NASA Astrophysics Data System (ADS)

Kan, Tian; Zheng, Youye; Gao, Shunbao

2016-04-01

The Banbule Pb-Zn-Cu skarn deposit is located in the Longger-Gongbujiangda volcanic magma arc in the Gangdese-Nyainqentanglha Plate. It is the only lead-zinc polymetallic deposit discovered in the westernmost Nyainqentanglha metallogenic belt. The measured and indicated resources include 0.9 Mt of Pb+Zn (4.77% Pb and 4.74% Zn, respectively), 6499 t of Cu, and 178 t of Ag (18.75g/t Ag). The orebodies mainly occur as lenses, veins and irregular shapes in the contact zone between the quartz-porphyry and limestone of the Upper Permian Xiala Formation, or in the boundaries between limestone and sandstone. Pb-Zn-Cu mineralization in the Banbule deposit is closely associated with skarns. The ore minerals are dominated by galena, sphalerite, chalcopyrite, bornite, and magnetite, with subordinate pyrite, malachite, and azurite. The gangue minerals are mainly garnet, actinolite, diopside, quartz, and calcite. The ore-related quartz-porphyry displays LA-ICP-MS zircon U-Pb age of 77.31±0.74 Ma. The δ34S values of sulfides define a narrow range of -0.8 to 4.7‰ indicating a magmatic source for the ore-forming materials. Lead isotopic systematics yield 206Pb/204Pb of 18.698 to 18.752, 207Pb/204Pb of 15.696 to 15.760, and 208Pb/204Pb of 39.097 to 39.320. The data points are constrained around the growth curves of upper crust and orogenic belt according to the tectonic discrimination diagrams. The calculated Δβ - Δγ values plot within the magmatic field according to the discrimination diagram of Zhu et al. (1995). The S-Pb isotopic data suggest that Bangbule is a typical skarn deposit, and the Pb-Zn-Cu mineralization is genetically related to the quartz-porphyry in the mining district. The discovery of the Bangbule deposit indicates that there is metallogenic potential in the westernmost Nyainqentanglha belt, which is of great importance for the exploration work in this area.

R 3Au 9 Pn ( R = Y, Gd–Tm; Pn = Sb, Bi): A link between Cu 10Sn 3 and Gd 14Ag 51

DOE Office of Scientific and Technical Information (OSTI.GOV)

Celania, Chris; Smetana, Volodymyr; Provino, Alessia

A new series of intermetallic compounds R 3Au 9 Pn ( R = Y, Gd–Tm; Pn = Sb, Bi) has been discovered during the explorations of the Au-rich parts of rare-earth-containing ternary systems with p-block elements. The existence of the series is strongly restricted by both geometric and electronic factors. R 3Au 9 Pn compounds crystallize in the hexagonal crystal system with space group P6 3/m (a = 8.08–8.24 Å, c = 8.98–9.08 Å). All compounds feature Au- Pn, formally anionic, networks built up by layers of alternating edge-sharing Au@Au 6 and Sb@Au 6 trigonal antiprisms of overall composition Aumore » 6/2 Pn connected through additional Au atoms and separated by a triangular cationic substructure formed by R atoms. From a first look, the series appears to be isostructural with recently reported R 3Au 7Sn 3 (a ternary ordered derivative of the Cu 10Sn 3-structure type), but no example of R 3Au 9M is known when M is a triel or tetrel element. R 3Au 9 Pn also contains Au@Au 6Au 2 R 3 fully capped trigonal prisms, which are found to be isostructural with those found in the well-researched R 14Au 51 series. This structural motif, not present in R 3Au 7Sn 3, represents a previously unrecognized link between Cu 10Sn 3 and Gd 14Ag 51 parent structure types. Magnetic property measurements carried out for Ho 3Au 9Sb reveal a complex magnetic structure characterized by antiferromagnetic interactions at low temperature ( T N = 10 K). Two metamagnetic transitions occur at high field with a change from antiferromagnetic toward ferromagnetic ordering. Density functional theory based computations were performed to understand the materials’ properties and to shed some light on the stability ranges. As a result, this allowed a better understanding of the bonding pattern, especially of the Au-containing substructure, and elucidation of the role of the third element in the stability of the structure type.« less

R 3Au 9 Pn ( R = Y, Gd–Tm; Pn = Sb, Bi): A link between Cu 10Sn 3 and Gd 14Ag 51

DOE PAGES

Celania, Chris; Smetana, Volodymyr; Provino, Alessia; ...

2017-06-05

A new series of intermetallic compounds R 3Au 9 Pn ( R = Y, Gd–Tm; Pn = Sb, Bi) has been discovered during the explorations of the Au-rich parts of rare-earth-containing ternary systems with p-block elements. The existence of the series is strongly restricted by both geometric and electronic factors. R 3Au 9 Pn compounds crystallize in the hexagonal crystal system with space group P6 3/m (a = 8.08–8.24 Å, c = 8.98–9.08 Å). All compounds feature Au- Pn, formally anionic, networks built up by layers of alternating edge-sharing Au@Au 6 and Sb@Au 6 trigonal antiprisms of overall composition Aumore » 6/2 Pn connected through additional Au atoms and separated by a triangular cationic substructure formed by R atoms. From a first look, the series appears to be isostructural with recently reported R 3Au 7Sn 3 (a ternary ordered derivative of the Cu 10Sn 3-structure type), but no example of R 3Au 9M is known when M is a triel or tetrel element. R 3Au 9 Pn also contains Au@Au 6Au 2 R 3 fully capped trigonal prisms, which are found to be isostructural with those found in the well-researched R 14Au 51 series. This structural motif, not present in R 3Au 7Sn 3, represents a previously unrecognized link between Cu 10Sn 3 and Gd 14Ag 51 parent structure types. Magnetic property measurements carried out for Ho 3Au 9Sb reveal a complex magnetic structure characterized by antiferromagnetic interactions at low temperature ( T N = 10 K). Two metamagnetic transitions occur at high field with a change from antiferromagnetic toward ferromagnetic ordering. Density functional theory based computations were performed to understand the materials’ properties and to shed some light on the stability ranges. As a result, this allowed a better understanding of the bonding pattern, especially of the Au-containing substructure, and elucidation of the role of the third element in the stability of the structure type.« less

Enhanced peroxidase-like properties of Au@Pt DNs/NG/Cu2+ and application of sandwich-type electrochemical immunosensor for highly sensitive detection of CEA.

PubMed

Lv, Hui; Li, Yueyun; Zhang, Xiaobo; Gao, Zengqiang; Zhang, Chunyan; Zhang, Shuan; Dong, Yunhui

2018-07-30

Effective treatment of cancer depends upon the early detection of the tumor marker. Here, we report on the development of a new immunosensor for early detection of carcinoembryonic antigen (CEA). Cubic Au@Pt dendritic nanomaterials functionalized nitrogen-doped graphene loaded with copper ion (Au@Pt DNs/NG/Cu 2+ ) with enhanced peroxidase-like properties was synthesized as labels to effectively capture and immobilize secondary anti-CEA. The Au@Pt DNs with more active surface area could efficiently enhance electrocatalysis for reduction of hydrogen peroxide (H 2 O 2 ). Meanwhile, with good conductivity and large specific surface area, NG can immobilize a large amount of Au@Pt DNs. Furthermore, after adsorbed Cu 2+ can further promote the redox of H 2 O 2 and amplify the signal of the immunosensor. For the immobilization of primary antibodies, Au nanoparticles functionalized polydopamine (Au@PDA) were used as transducing materials to modify glassy carbon electrodes and enhance the electron transfer efficiently. Under optimal conditions, the immunosensor exhibited a satisfactory response to CEA with a limit detection of 0.167 pg/mL and linear detection range from 0.5 pg/mL to 50 ng/mL. Based on the high sensitivity and specificity of the immunosensor, we propose this multiple amplified biosensor for early detection of CEA. Copyright © 2018 Elsevier B.V. All rights reserved.

Rapid detection of Cu(2+) by a paper-based microfluidic device coated with bovine serum albumin (BSA)-Au nanoclusters.

PubMed

Fang, Xueen; Zhao, Qianqian; Cao, Hongmei; Liu, Juan; Guan, Ming; Kong, Jilie

2015-11-21

In this work, bovine serum albumin (BSA)-Au nanoclusters were used to coat a paper-based microfluidic device. This device acted as a Cu(2+) biosensor that showed fluorescence quenching on detection of copper ions. The detection limit of this sensor could be adjusted by altering the water absorbing capacity of the device. Qualitative and semi-quantitative results could be obtained visually without the aid of any advanced instruments. This sensor could test Cu(2+) rapidly with high specificity and sensitivity, which would be useful for point-of-care testing (POCT).

Geochemical element mobility during the hydrothermal alteration in the Tepeoba porphyry Cu-Mo-Au deposits at Balikesir, NW Turkey

NASA Astrophysics Data System (ADS)

Abdelnasser, Amr; Kiran Yildirim, Demet; Doner, Zeynep; Kumral, Mustafa

2016-04-01

The Tepeoba porphyry Cu-Mo-Au deposit represents one of the important copper source and mineral deposits in the Anatolian tectonic belt at Balikesir province, NW Turkey. It considered as a vein-type deposit locally associated with intense hydrothermal alteration within the brecciation, quartz stockwork veining, and brittle fracture zones in the main host rock that represented by hornfels, as well as generally related to the shallow intermediate to silicic intrusive Eybek pluton. Based on the field and geologic relationships and types of ore mineral assemblages and the accompanied alteration types, there are two mineralization zones; hypogene (primary) and oxidation/supergene zones are observed associated with three alteration zones; potassic, phyllic, and propylitic zones related to this porphyry deposit. The phyllic and propylitic alterations locally surrounded the potassic alteration. The ore minerals related to the hypogene zone represented by mostly chalcopyrite, Molybdenite, and pyrite with subordinate amount of marcasite, enargite, and gold. On the other hand they include mainly cuprite with chalcopyrite, pyrite and gold as well as hematite and goethite at the oxidation/supergene zone. This study deals with the quantitative calculations of the mass/volume changes (gains and losses) of the major and trace elements during the different episodes of alteration in this porphyry deposit. These mass balance data reveal that the potassic alteration zone that the main Cu- and Mo-enriched zone, has enrichment of K, Si, Fe, and Mg, and depletion of Na referring to replacement of plagioclase and amphibole by K-feldspar, sericite and biotite. While the propylitic alteration that is the main Mo- and Au-enriched zone is accompanied with K and Na depletion with enrichment of Si, Fe, Mg, and Ca forming chlorite, epidote, carbonate and pyrite. On the other hand the phyllic alteration that occurred in the outer part around the potassic alteration, characterized by less amount

Enhanced nonlinear current-voltage behavior in Au nanoparticle dispersed CaCu 3 Ti 4 O 12 composite films

NASA Astrophysics Data System (ADS)

Chen, Cong; Wang, Can; Ning, Tingyin; Lu, Heng; Zhou, Yueliang; Ming, Hai; Wang, Pei; Zhang, Dongxiang; Yang, Guozhen

2011-10-01

An enhanced nonlinear current-voltage behavior has been observed in Au nanoparticle dispersed CaCu 3Ti 4O 12 composite films. The double Schottky barrier model is used to explain the enhanced nonlinearity in I-V curves. According to the energy-band model and fitting result, the nonlinearity in Au: CCTO film is mainly governed by thermionic emission in the reverse-biased Schottky barrier. This result not only supports the mechanism of double Schottky barrier in CCTO, but also indicates that the nonlinearity of current-voltage behavior could be improved in nanometal composite films, which has great significance for the resistance switching devices.

Matrix infrared spectroscopy and quantum-chemical calculations for the coinage-metal fluorides: comparisons of Ar-AuF, Ne-AuF, and Molecules MF2 and MF3.

PubMed

Wang, Xuefeng; Andrews, Lester; Brosi, Felix; Riedel, Sebastian

2013-01-21

The reactions of laser-ablated Au, Ag, and Cu atoms with F(2) in excess argon and neon gave new absorptions in the M-F stretching region of their IR spectra, which were assigned to metal-fluoride species. For gold, a Ng-AuF bond was identified in mixed neon/argon samples. However, this bonding was much weaker with AgF and CuF. Molecules MF(2) and MF(3) (M=Au, Ag, Cu) were identified from the isotopic distribution of the Cu and Ag atoms, comparison of the frequencies for three metal fluorides, and theoretical frequency calculations. The AuF(5) molecule was characterized by its strongest stretching mode and theoretical frequency calculations. Additional evidence was observed for the formation of the Au(2) F(6) molecule. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Geochemical behavior of rare earth elements of the hydrothermal alterations within the Tepeoba porphyry Cu-Mo-Au deposits at Balikesir, NW Turkey

NASA Astrophysics Data System (ADS)

Doner, Zeynep; Abdelnasser, Amr; Kiran Yildirim, Demet; Kumral, Mustafa

2016-04-01

This work reports the geochemical characteristics and behavior of the rare earth elements (REE) of the hydrothermal alteration of the Tepeoba porphyry Cu-Mo-Au deposit located in the Anatolian tectonic belt at Biga peninsula (Locally Balikesir province), NW Turkey. The Cu-Mo-Au mineralization at this deposit hosted in the hornfels rocks and related to the silicic to intermediate intrusion of Eybek pluton. It locally formed with brecciated zones and quartz vein stockworks, as well as the brittle fracture zones associated with intense hydrothermal alteration. Three main alteration zones with gradual boundaries formed in the mine area in the hornfels rock that represents the host rock, along that contact the Eybek pluton; potassic, propylitic and phyllic alteration zones. The potassic alteration zone that formed at the center having high amount of Cu-sulfide minerals contains biotite, muscovite, and sericite with less amount of K-feldspar and associated with tourmalinization alteration. The propylitic alteration surrounds the potassic alteration having high amount of Mo and Au and contains chlorite, albite, epidote, calcite and pyrite. The phyllic alteration zone also surrounds the potassic alteration containing quartz, sericite and pyrite minerals. Based on the REE characteristics and content and when we correlate the Alteration index (AI) with the light REEs and heavy REEs of each alteration zone, it concluded that the light REEs decrease and heavy REEs increase during the alteration processes. The relationships between K2O index with Eu/Eu* and Sr/Sr* reveals a positive correlation in the potassic and phyllic alteration zones and a negative correlation in the propylitic alteration zone. This refers to the hydrothermal solution which is responsible for the studied porphyry deposits and associated potassic and phyllic alterations has a positive Eu and Sr anomaly as well as these elements were added to the altered rock from the hydrothermal solution. Keywords: Rare

Partitioning of V, Mn, Co, Ni, Cu, Zn, As, Mo, Ag, Sn, Sb, W, Au, Pb, and Bi between sulfide phases and hydrous basanite melt at upper mantle conditions

NASA Astrophysics Data System (ADS)

Li, Yuan; Audétat, Andreas

2012-11-01

The partitioning of 15 major to trace metals between monosulfide solid solution (MSS), sulfide liquid (SL) and mafic silicate melt (SM) was determined in piston-cylinder experiments performed at 1175-1300 °C, 1.5-3.0 GPa and oxygen fugacities ranging from 3.1 log units below to 1.0 log units above the quartz-fayalite-magnetite fO2 buffer, which conditions are representative of partial melting in the upper mantle in different tectonic settings. The silicate melt was produced by partial melting of a natural, amphibole-rich mantle source rock, resulting in hydrous (˜5 wt% H2O) basanitic melts similar to low-degree partial melts of metasomatized mantle, whereas the major element composition of the starting sulfide (˜52 wt% Fe; 39 wt% S; 7 wt% Ni; 2 wt% Cu) was similar to the average composition of sulfides in this environment. SL/SM partition coefficients are high (≥100) for Au, Ni, Cu, Ag, Bi, intermediate (1-100) for Co, Pb, Sn, Sb (±As, Mo), and low (≤1) for the remaining elements. MSS/SM partition coefficients are generally lower than SL/SM partition coefficients and are high (≥100) for Ni, Cu, Au, intermediate (1-100) for Co, Ag (±Bi, Mo), and low (≤1) for the remaining elements. Most sulfide-silicate melt partition coefficients vary as a function of fO2, with Mo, Bi, As (±W) varying by a factor >10 over the investigated fO2 range, Sb, Ag, Sn (±V) varying by a factor of 3-10, and Pb, Cu, Ni, Co, Au, Zn, Mn varying by a factor of 3-10. The partitioning data were used to model the behavior of Cu, Au, Ag, and Bi during partial melting of upper mantle and during fractional crystallization of primitive MORB and arc magmas. Sulfide phase relationships and comparison of the modeling results with reported Cu, Au, Ag, and Bi concentrations from MORB and arc magmas suggest that: (i) MSS is the dominant sulfide in the source region of arc magmas, and thus that Au/Cu ratios in the silicate melt and residual sulfides may decrease with increasing degree of

Size, shape, and compositional effects on the order-disorder phase transitions in Au-Cu and Pt-M (M = Fe, Co, and Ni) nanocluster alloys.

PubMed

Kaatz, Forrest H; Bultheel, Adhemar

2018-08-24

Au-Cu and Pt-M (M = Fe, Co, and Ni) nanocluster alloys are currently being investigated world-wide by many researchers for their interesting catalytic and nanophase properties. The low temperature behavior of the phase diagrams is not well understood for alloys with nanometer sizes and shapes. We consider two models for low temperature ordering in the phase diagrams of Au-Cu and Pt-M nanocluster alloys. These models are valid for sizes ∼5 nm and approach bulk values for sizes ∼20 nm. We study the phase transitions in nanoclusters with cubic, octahedral, and cuboctahedral shapes, covering the compositions of interest. These models are based on studying the melting temperatures in nanoclusters using the regular solution, mixing model for alloys. From our data, experiments on nanocubes about 5 nm in size, of stoichiometric AuCu and PtM composition, could help differentiate between the models. Dispersion data shows that for the three shapes considered, octahedra have the highest percentage of surface atoms for the same relative diameter. We summarize the effects of structural ordering on the catalytic activity and suggest a method to avoid sintering during annealing of Pt-M alloys.

Fluid Inclusion characteristics of syn-late orogenic Co-Ni-Cu-Au deposits in the Siegerland District of the Rhenish Massif, Germany

NASA Astrophysics Data System (ADS)

Wohlgemuth, Christoph; Hellmann, André; Meyer, Franz Michael

2013-04-01

The Siegerland District is located in the fold-and-thrust-belt of the Rhenish Massif and hosts various syn- late orogenic vein-hosted hydrothermal mineralization types. Peak-metamorphism and deformation occurred at 312-316 ± 10 Ma (Ahrendt et al., 1978) at pT-conditions of 280 - 320 °C and 0.7 - 1.4 kbar (Hein, 1993). The district is known for synorogenic siderite-quartz mineralization formed during peak-metamorphic conditions. At least 4 syn-late orogenic mineralization types are distinguished: Co-Ni-Cu-Au, Pb-Zn-Cu, Sb-Au and hematite-digenite-bornite mineralization (Hellmann et al., 2012b). Co-Ni-Cu-Au mineralization of the Siegerland District belongs to the recently defined class of metasediment hosted synorogenic Co-Cu-Au deposits (i.e. Slack et al, 2010). Ore minerals are Fe-Co-Ni sulpharsenides, bearing invisible gold, chalcopyrite, and minor As-bearing pyrite. The gangue is quartz. The alteration mineralogy comprises chlorite, illite-muscovite and quartz. The epigenetic quartz veins are closely related to the formation of reverse faults (Hellmann et al., 2011a). Microthermometric studies of fluid inclusions concerning the relationship between mineralization and microstructures have not been done so far for this deposit-class and this will be addressed here. Fluid inclusions are investigated in hydrothermally formed vein-quartz, selected from Co-Ni-Cu-Au mineralization bearing veins showing only minor overprints by later mineralization types. Two quartz generations are distinguished: subhedral quartz-I showing growth zonation and fine grained, recrystallized- and newly formed quartz-II grains forming irregular masses and fracture fillings in quartz-I. Co-Ni-Fe sulpharsenides and chalcopyrite are closely intergrown with quartz-II, implying their contemperaneous formation. However, fluid inclusions in quartz-II are often small, therefore fluid inclusions in quartz-I have been mostly investigated. In total, 180 inclusions from 4 different deposits have been

Typing mineral deposits using their grades and tonnages in an artificial neural network

USGS Publications Warehouse

Singer, Donald A.; Kouda, Ryoichi

2003-01-01

A test of the ability of a probabilistic neural network to classify deposits into types on the basis of deposit tonnage and average Cu, Mo, Ag, Au, Zn, and Pb grades is conducted. The purpose is to examine whether this type of system might serve as a basis for integrating geoscience information available in large mineral databases to classify sites by deposit type. Benefits of proper classification of many sites in large regions are relatively rapid identification of terranes permissive for deposit types and recognition of specific sites perhaps worthy of exploring further.Total tonnages and average grades of 1,137 well-explored deposits identified in published grade and tonnage models representing 13 deposit types were used to train and test the network. Tonnages were transformed by logarithms and grades by square roots to reduce effects of skewness. All values were scaled by subtracting the variable's mean and dividing by its standard deviation. Half of the deposits were selected randomly to be used in training the probabilistic neural network and the other half were used for independent testing. Tests were performed with a probabilistic neural network employing a Gaussian kernel and separate sigma weights for each class (type) and each variable (grade or tonnage).Deposit types were selected to challenge the neural network. For many types, tonnages or average grades are significantly different from other types, but individual deposits may plot in the grade and tonnage space of more than one type. Porphyry Cu, porphyry Cu-Au, and porphyry Cu-Mo types have similar tonnages and relatively small differences in grades. Redbed Cu deposits typically have tonnages that could be confused with porphyry Cu deposits, also contain Cu and, in some situations, Ag. Cyprus and kuroko massive sulfide types have about the same tonnages. Cu, Zn, Ag, and Au grades. Polymetallic vein, sedimentary exhalative Zn-Pb, and Zn-Pb skarn types contain many of the same metals. Sediment

Spin Polarization of Mg-23 in Mg-24 + Au, Cu and Al Collisions at 91 A MeV

NASA Technical Reports Server (NTRS)

Matsuta, K.; Fukuda, S.; Izumikawa, T.; Tanigaki, M.; Fukuda, M.; Nakazato, M.; Mihara, M.; Onishi, T.; Yamaguchi, T.; Miyake, T.

1994-01-01

Spin polarization of beta-emitting fragment Mg-23(I(sup pi) = 3/2(sup +), T(sub 1/2 = l1.3 s) produced through the projectile fragmentation process in Mg-24 + Au, Cu and Al collisions has been observed at 91 AMeV. General trend in the observed momentum dependence of polarization is reproduced well qualitatively by a simple fragmentation model based on the participant-spectator picture, for heavy and light targets. However the polarization behavior differs from this model in tern of zero crossing momentum, which become prominent in the case of Cu target, where the polarization is not monotone function of the fragment momentum.

Near-edge study of gold-substituted YBa2Cu3O(7-delta)

NASA Technical Reports Server (NTRS)

Ruckman, Mark W.; Hepp, Aloysius F.

1991-01-01

The valence of Cu and Au in YBa2Au0.3Cu2.7O7-delta was investigated using X-ray absorption near edge structure (XANES). X-ray and neutron diffraction studies indicate that Au goes on the Cu(1) site and Cu K-edge XANES shows that this has little effect on the oxidation state of the remaining copper. The Au L3 edge develops a white line feature whose position lies between that of trivalent gold oxide and monovalent potassium gold cyanide, and whose height relative to the edge step is smaller than in the two reference compounds. The appearance of the Au L3 edge suggests that fewer Au 3d states are involved in forming the Au-O bond in YBa2Au0.3Cu2.7O7-delta than in trivalent gold oxide.

Near-edge study of gold-substituted YBa2Cu3O(7-delta)

NASA Technical Reports Server (NTRS)

Ruckman, Mark W.; Hepp, Aloysius F.

1991-01-01

The valence of Cu and Au in YBa2Au0.3Cu2.7O7-delta was investigated using x-ray absorption near edge structure (XANES). X-ray and neutron diffraction studies indicate that Au goes on the Cu(1) site and Cu K-edge XANES shows that this has little effect on the oxidation state of the remaining copper. The Au L3 edge develops a white line feature whose position lies between that of trivalent gold oxide and monovalent potassium gold cyanide, and whose height relative to the edge step is smaller than in the two reference compounds. The appearance of the Au L3 edge suggests that fewer Au 3d states are involved in forming the Au-O bond in YBa2Au0.3Cu2.7O7-delta than in trivalent gold oxide.

The partitioning of Cu, Au and Mo between liquid and vapor at magmatic temperatures and its implications for the genesis of magmatic-hydrothermal ore deposits

NASA Astrophysics Data System (ADS)

Zajacz, Zoltán; Candela, Philip A.; Piccoli, Philip M.

2017-06-01

The partition coefficients of Cu, Au and Mo between liquid and vapor were determined at P = 130 MPa and T = 900 °C, and P = 90 MPa and T = 650 °C and redox conditions favoring the dominance of reduced S species in the fluid. The experiments at 900 °C were conducted in rapid-quench Molybdenum-Hafnium Carbide externally-heated pressure vessel assemblies, whereas those at 650 °C were run in René41 pressure vessels. The fluids were sampled at run conditions using the synthetic fluid inclusion technique. The host quartz was fractured in situ during the experiments ensuring the entrapment of equilibrium fluids. A new method was developed to quantify the composition of the vapor inclusions from LA-ICPMS analyses relying on the use of boron as an internal standard, an element that fractionates between vapor and liquid to a very small degree. The bulk starting fluid compositions closely represented those expected to exsolve from felsic silicate melts in upper crustal magma reservoirs (0.64 m NaCl, 0.32 m KCl, ±0.2 m HCl and/or 4 wt% S). The experiments were conducted in Au97Cu3 alloy capsules allowing the simultaneous determination of apparent Au and Cu solubilities in the liquid and the vapor phase. Though the apparent metal solubilities were strongly affected by the addition of HCl and S in both phases, all three elements were found to preferentially partition to a liquid phase at all studied conditions with an increasing degree of preference for the liquid in the following order Au < Cu < Mo. The presence of HCl and S did not have a significant effect on the liquid/vapor partition coefficients of either Au or Cu, whereas the presence of HCl slightly shifted the partitioning of Mo in favor of the vapor. Ore metal partition coefficients normalized to that of Na (Ki-Naliq/ vap =Diliq/vap /DNaliq/vap) fall in the following ranges respectively for each studied metal: KAu-Naliq / vap = 0.20 ± 0.07-0.50 ± 0.19 (1σ); KCu-Naliq / vap = 0.36 ± 0.12-0.76 ± 0.22; KMo

Uranium-lead dating of hydrothermal zircon and monazite from the Sin Quyen Fe-Cu-REE-Au-(U) deposit, northwestern Vietnam

NASA Astrophysics Data System (ADS)

Li, Xiao-Chun; Zhou, Mei-Fu; Chen, Wei Terry; Zhao, Xin-Fu; Tran, MyDung

2018-03-01

The Sin Quyen deposit in northwestern Vietnam contains economic concentrations of Cu, Au and LREE, and sub-economic concentration of U. In this deposit, massive and banded replacement ores are hosted in Neoproterozoic metapelite. The paragenetic sequence includes sodic alteration (stage I), calcic-potassic alteration and associated Fe-REE-(U) mineralization (stage II), Cu-Au mineralization (stage III), and sulfide-(quartz-carbonate) veins (stage IV). The Sin Quyen deposit experienced an extensive post-ore metamorphic overprint, which makes it difficult to precisely determine the mineralization age. In this study, zircon and monazite U-Pb geochronometers and the Rb-Sr isochron method are used to constrain the timing of mineralization. Zircon grains in the ore are closely intergrown or texturally associated with hydrothermal minerals of stage II (e.g., garnet, allanite, and hedenbergite). They may contain primary fluid inclusions and display irregular zoning in cathodoluminescence (CL) images. Zircon grains are rich in U (688 to 2902 ppm) and poor in Th (0.2 to 2.9 ppm). Their δ18OV-SMOW values range from 11.9 to 14.0‰, higher than those of typical magmatic zircon. These textural and compositional features imply that zircon precipitated from 18O- and U-rich hydrothermal fluids, coeval with the minerals of stage II. Monazite occurs in close association with stage II magnetite and allanite and has low contents of Th (<2700 ppm), indicative of a hydrothermal origin. Hydrothermal zircon and monazite have indistinguishable U-Pb ages of 841 ± 12 and 836 ± 18 Ma, respectively, representing the timing of Fe-REE mineralization. There is no direct isotopic constraint on the timing of the Cu-Au mineralization, but geological observations suggest that the Cu-Au and Fe-REE ores most likely formed within a single evolved hydrothermal process. In the plot of 87Rb/86Sr vs. 87Sr/86Sr, the composition of bulk-ore and biotite separates from ore lie along a reference line for 30 Ma

Copper-based alloys, crystallographic and crystallochemical parameters of alloys in binary systems Cu-Me (Me=Co, Rh, Ir, Cu, Ag, Au, Ni, Pd, Pt)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porobova, Svetlana, E-mail: porobova.sveta@yandex.ru; Loskutov, Oleg, E-mail: lom58@mail.ru; Markova, Tat’jana, E-mail: patriot-rf@mail.ru

2016-01-15

The article presents the results of the analysis of phase equilibrium of ordered phases in binary systems based on copper Cu- Me (where Me - Co, Rh, Ir, Ag, Au, Ni, Pd, Pt) to find correlations of crystallochemical and crystallographic factors. It is established that the packing index in disordered solid solutions in binary systems based on copper is close to the value of 0.74 against the background of an insignificant deviation of atomic volumes from the Zen’s law.

Forming chemical composition of surface waters in the Arctic as "water - rock" interaction. Case study of lake Inari and river Paz

NASA Astrophysics Data System (ADS)

Mazukhina, Svetlana; Sandimirov, Sergey; Pozhilenko, Vladimir; Ivanov, Stanislav; Maksimova, Viktoriia

2017-04-01

Due to the depletion of fresh water supplies and the deterioration of their quality as a result of anthropogenic impact on the Arctic ecosystems, the research questions of forming surface and ground waters, their interactions with the rocks, development of the foundations for their rational use and protection are of great fundamental and practical importance. The aim of the work is to evaluate the influence of the chemical composition of rocks of the northern part of the Fennoscandian (Baltic) shield on forming surface waters chemical composition (Lake Inari, river Paz) using physical-chemical modeling (Chudnenko, 2010, Selector software package). River Paz (Paatsjoki) is the largest river in North Fennoscandia and flows through the territory of three countries - Finland, Russia and Norway. It originates from Lake Inari, which a large number of streams and rivers flow into, coming from the mountain range of the northern Finland (Maanselkä hill). Within the catchment of inflows feeding the lake Inari and river Paz in its upper flow there are mainly diverse early Precambrian metamorphic and intrusive rocks of the Lapland granulite belt and its framing, and to a lesser extent - various gneisses and migmatites with relicts of amphibolites, granitic gneisses, plagioclase and plagio- and plagiomicrocline granites, and quartz diorites of Inari terrane (Meriläinen, 1976, fig 1; Hörmann et al, 1980, fig 1; Geologicalmap, 2001). Basing on the techniques developed earlier (Mazukhina, 2012), and the data of monitoring of the chemical composition of surface waters and investigation of the chemical composition of the rocks, physical-chemical modeling (FCM) (Selector software package) was carried out. FCM includes 34 independent components (Al-B-Br-Ar-He-Ne-C-Ca-Cl-F-Fe-K-Mg-Mn-N-Na-P-S-Si-Sr-Cu-Zn-Ni-Pb-V-Ba-Co-Cr-Hg-As-Cd-H-O-e), 996 dependent components, of them 369 in aqueous solution, 76 in the gas phase, 111 liquid hydrocarbons, and 440 solid phases, organic and mineral

Au-HKUST-1 Composite Nanocapsules: Synthesis with a Coordination Replication Strategy and Catalysis on CO Oxidation.

PubMed

Liu, Yongxin; Zhang, Jiali; Song, Lingxiao; Xu, Wenyuan; Guo, Zanru; Yang, Xiaomin; Wu, Xiaoxin; Chen, Xi

2016-09-07

A novel coordination replication of Cu2O redox-template strategy is reported to efficiently fabricate Au-HKUST-1 composite nanocapsule, with a HKUST-1 sandwich shell and an embedded Au nanoparticles layer. The novel synthesis procedure involves forming Au nanoparticles on the surface of Cu2O, transforming partial Cu2O into HKUST-1 shell via coordination replication, and removing the residual Cu2O by acid. The as-prepared Au-HKUST-1 composite nanocapsules displayed high catalytic activity on CO oxidation.

The partitioning of Fe, Ni, Cu, Pt, and Au between sulfide, metal, and fluid phases: A pilot study

NASA Astrophysics Data System (ADS)

Ballhaus, C.; Ryan, C. G.; Mernagh, T. P.; Green, D. H.

1994-01-01

This paper describes new experimental and analytical techniques to study element partitioning behavior between crystalline material and a late- to post-magmatic fluid phase. Samples of the fluid phase are isolated at experimental run conditions as synthetic fluid in quartz. Individual fluid inclusions are later analyzed for dissolved metals using Proton Induced X-ray Emission (PIXE). Back reactions between fluid and solid phases during quenching are prevented because the fluid is isolated at the experimental pressure, temperature ( P, T) conditions before quenching occurs. The technique is applied to study the partitioning of chalcophile elements (Fe, Ni, Cu, Pt and Au) between sulfide phases, metal alloys and supercritical SiO 2-NaCl-saturated H2O ± CH4- CO2- H2S fluids. Synthetic Ni-Cu-rich monosulfide solid solution (mss) doped with PtS or Au is packed in a quartz capsule and, together with a hydrogen buffer capsule and compounds to generate a fluid phase, welded shut in an outer Pt or Au metal capsule. The fluid phase is generated by combustion and reaction of various C-H-O fluid components during heating. Depending on capsule material and sample composition, the run products consist of platiniferous or auriferous mss, Pt-Fe, or ( Au, Cu) alloy phases, PtS, Fe 3O 4, sometimes a Cu-rich sulfide melt, and a fluid phase. Samples of the fluid are trapped in the walls of the quartz sample capsule as polyphase fluid inclusions. All phases are now available for analysis: fluid speciation is analyzed by piercing the outer metal capsule under vacuum and feeding the released fluid into a mass spectrometer. Phases and components within fluid inclusions are identified with Raman spectroscopy. Platinum and gold in solid solution in mss are determined with a CAMECA SX50 electron microanalyser. Metal contents trapped in selected fluid inclusions are determined quantitatively by in situ analysis with a proton microprobe using PIXE and a correction procedure specifically

Friction force microscopy at a regularly stepped Au(665) electrode: Anisotropy effects

NASA Astrophysics Data System (ADS)

Podgaynyy, Nikolay; Iqbal, Shahid; Baltruschat, Helmut

2015-01-01

Using friction force microscopy, friction was determined for the AFM-tip scanning parallel and vertically to the monoatomic steps of Au(665) electrode for different coverages of Cu in sulfuric acid. When the tip was scanning parallel to the steps, the results were similar to those obtained before for a Au(111) surface: a higher coverage of Cu leads to an increased friction. However, differently from Au(111), no transitions in the friction coefficient were observed with increasing load. Atomic stick slip was observed both for the Au surface and the √{ 3} × √{ 3} honeycomb Cu adlayer with a Cu coverage of 2/3. When the tip was scanning perpendicular to the steps, friction did not depend much on coverage; astonishingly, atomic stick slip was also observed.

Single Probe for Imaging and Biosensing of pH, Cu(2+) Ions, and pH/Cu(2+) in Live Cells with Ratiometric Fluorescence Signals.

PubMed

Han, Yingying; Ding, Changqin; Zhou, Jie; Tian, Yang

2015-01-01

It is very essential to disentangle the complicated inter-relationship between pH and Cu in the signal transduction and homeostasis. To this end, reporters that can display distinct signals to pH and Cu are highly valuable. Unfortunately, there is still no report on the development of biosensors that can simultaneously respond to pH and Cu(2+), to the best of our knowledge. In this work, we developed a single fluorescent probe, AuNC@FITC@DEAC (AuNC, gold cluster; FITC, fluorescein isothiocyanate; DEAC, 7-diethylaminocoumarin-3-carboxylic acid), for biosensing of pH, Cu(2+), and pH/Cu(2+) with different ratiometric fluorescent signals. First, 2,2',2″-(2,2',2″-nitrilotris(ethane-2,1-diyl)tris((pyridin-2-yl-methyl)azanediyl))triethanethiol (TPAASH) was designed for specific recognition of Cu(2+), as well as for organic ligand to synthesize fluorescent AuNCs. Then, pH-sensitive molecule, FITC emitting at 518 nm, and inner reference molecule, DEAC with emission peak at 472 nm, were simultaneously conjugated on the surface of AuNCs emitting at 722 nm, thus, constructing a single fluorescent probe, AuNC@FITC@DEAC, to sensing pH, Cu(2+), and pH/Cu(2+) excited by 405 nm light. The developed probe exhibited high selectivity and accuracy for independent determination of pH and Cu(2+) against reactive oxygen species (ROS), other metal ions, amino acids, and even copper-containing proteins. The AuNC-based inorganic-organic probe with good cell-permeability and high biocompatibility was eventually applied in monitoring both pH and Cu(2+) and in understanding the interplaying roles of Cu(2+) and pH in live cells by ratiometric multicolor fluorescent imaging.

Dilute electrodeposition of TiO2 and ZnO thin film memristors on Cu substrate

NASA Astrophysics Data System (ADS)

Fauzi, F. B.; Ani, M. H.; Herman, S. H.; Mohamed, M. A.

2018-03-01

Memristor has become one of the alternatives to replace the current memory technologies. Fabrication of titanium dioxide, TiO2 memristor has been extensively studied by using various deposition methods. However, recently more researches have been done to explore the compatibility of other transition metal oxide, TMO such as zinc oxide, ZnO to be used as the active layer of the memristor. This paper highlights the simple and easy-control electrodeposition to deposit titanium, Ti and zinc, Zn thin film at room temperature and subsequent thermal oxidation at 600 °C. Gold, Au was then sputtered as top electrode to create metal-insulator-metal, MIM sandwich of Au/TiO2-Cu2O-CuO/Cu and Au/ZnO-Cu2O-CuO/Cu memristors. The structural, morphological and memristive properties were characterized using Field Emission Scanning Electron Microscopy, FESEM, X-Ray Diffraction, XRD and current-voltage, I-V measurement. Both Au/TiO2-Cu2O-CuO/Cu and Au/ZnO-Cu2O-CuO/Cu memristivity were identified by the pinched hysteresis loop with resistive ratio of 1.2 and 1.08 respectively. Empirical study on diffusivity of Ti4+, Zn2+ and O2‑ ions in both metal oxides show that the metal vacancies were formed, thus giving rise to its memristivity. The electrodeposited Au/TiO2-Cu2O-CuO/Cu and Au/ZnO-Cu2O-CuO/Cu memristors demonstrate comparable performances to previous studies using other methods.

Geochemistry and petrology of the indium-bearing polymetallic skarn ores at Pitkäranta, Ladoga Karelia, Russia

NASA Astrophysics Data System (ADS)

Valkama, M.; Sundblad, K.; Cook, N. J.; Ivashchenko, V. I.

2016-08-01

The historic mining district of Pitkäranta in the Ladoga region, Fennoscandian Shield, was exploited for Fe, Cu, Zn, Pb, Sn and Ag in the nineteenth to twentieth centuries. The Pitkäranta region is dominated by Palaeoproterozoic supracrustal rocks, which, together with gneissic Archaean dome structures, constitute an allochthonous terrane complex that amalgamated to the Archaean continent during the Svecokarelian orogeny at 1.9-1.8 Ga. This crustal complex was intruded by 1.8 Ga Late orogenic granites, 1.54 Ga anorogenic rapakivi granites and 1.45 Ga dolerites. The polymetallic skarn ores of Pitkäranta extend over a 25-km-long zone in Palaeoproterozoic supracrustal rocks and formed from hydrothermal solutions, which emanated from the anorogenic rapakivi granites and reacted with marble layers. Four major ore types are recognised after the dominating metal: Fe, Cu, Sn and Zn, respectively. These types are not restricted to individual mines or mine fields but represent end members in zonation patterns within each ore body. Pitkäranta was the second discovery site in the world for indium but has been without modern documentation for more than 75 years. The indium contents in the ores are up to 600 ppm, in most cases sphalerite-hosted. The only roquesite-bearing sample in this study had an indium grade of 291 ppm and an In/Zn ratio of 51 (close to the criteria for the limiting conditions for creating an In-rich mineral). The Pitkäranta ores have a potential for future small-scale exploitation, but all such plans are hampered by high contents if Bi, Cd and As.

Fabrication and characterization of copper oxide (CuO)–gold (Au)–titania (TiO{sub 2}) and copper oxide (CuO)–gold (Au)–indium tin oxide (ITO) nanowire heterostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chopra, Nitin, E-mail: nchopra@eng.ua.edu; Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL 35487; Shi, Wenwu

2014-10-15

Nanoscale heterostructures composed of standing copper oxide nanowires decorated with Au nanoparticles and shells of titania and indium tin oxide were fabricated. The fabrication process involved surfactant-free and wet-chemical nucleation of gold nanoparticles on copper oxide nanowires followed by a line-of-sight sputtering of titania or indium tin oxide. The heterostructures were characterized using high resolution electron microscopy, diffraction, and energy dispersive spectroscopy. The interfaces, morphologies, crystallinity, phases, and chemical compositions were analyzed. The process of direct nucleation of gold nanoparticles on copper oxide nanoparticles resulted in low energy interface with aligned lattice for both the components. Coatings of polycrystalline titaniamore » or amorphous indium tin oxide were deposited on standing copper oxide nanowire–gold nanoparticle heterostructures. Self-shadowing effect due to standing nanowire heterostructures was observed for line-of-sight sputter deposition of titania or indium tin oxide coatings. Finally, the heterostructures were studied using Raman spectroscopy and ultraviolet–visible spectroscopy, including band gap energy analysis. Tailing in the band gap energy at longer wavelengths (or lower energies) was observed for the nanowire heterostructures. - Highlights: • Heterostructures comprised of CuO nanowires coated with Au nanoparticles. • Au nanoparticles exhibited nearly flat and low energy interface with nanowire. • Heterostructures were further sputter-coated with oxide shell of TiO{sub 2} or ITO. • The process resulted in coating of polycrystalline TiO{sub 2} and amorphous ITO shell.« less

Data integration modeling applied to drill hole planning through semi-supervised learning: A case study from the Dalli Cu-Au porphyry deposit in the central Iran

NASA Astrophysics Data System (ADS)

Fatehi, Moslem; Asadi, Hooshang H.

2017-04-01

In this study, the application of a transductive support vector machine (TSVM), an innovative semi-supervised learning algorithm, has been proposed for mapping the potential drill targets at a detailed exploration stage. The semi-supervised learning method is a hybrid of supervised and unsupervised learning approach that simultaneously uses both training and non-training data to design a classifier. By using the TSVM algorithm, exploration layers at the Dalli porphyry Cu-Au deposit in the central Iran were integrated to locate the boundary of the Cu-Au mineralization for further drilling. By applying this algorithm on the non-training (unlabeled) and limited training (labeled) Dalli exploration data, the study area was classified in two domains of Cu-Au ore and waste. Then, the results were validated by the earlier block models created, using the available borehole and trench data. In addition to TSVM, the support vector machine (SVM) algorithm was also implemented on the study area for comparison. Thirty percent of the labeled exploration data was used to evaluate the performance of these two algorithms. The results revealed 87 percent correct recognition accuracy for the TSVM algorithm and 82 percent for the SVM algorithm. The deepest inclined borehole, recently drilled in the western part of the Dalli deposit, indicated that the boundary of Cu-Au mineralization, as identified by the TSVM algorithm, was only 15 m off from the actual boundary intersected by this borehole. According to the results of the TSVM algorithm, six new boreholes were suggested for further drilling at the Dalli deposit. This study showed that the TSVM algorithm could be a useful tool for enhancing the mineralization zones and consequently, ensuring a more accurate drill hole planning.

Laser-produced spectra and QED effects for Fe-, Co-, Cu-, and Zn-like ions of Au, Pb, Bi, Th, and U

NASA Technical Reports Server (NTRS)

Seely, J. F.; Ekberg, J. O.; Brown, C. M.; Feldman, U.; Behring, W. E.

1986-01-01

Spectra of very highly charged ions of Au, Pb, Bi, Th, and U have been observed in laser-produced plasmas generated by the OMEGA laser. Line identifications in the region 9-110 A were made for ions in the Fe, Co, Cu, and Zn isoelectronic sequences. Comparison of the measured wavelengths of the Cu-like ions with values calculated with and without QED corrections shows that the inclusion of QED corrections greatly improves the accuracy of the calculated 4s-4p wavelengths. However, significant differences between the observed and calculated values remain.

Depth Profile of Induced Magnetic Polarization in Cu Layers of Co/Cu(111) Metallic Superlattices by Resonant X-ray Magnetic Scattering at the Cu K Absorption Edge

NASA Astrophysics Data System (ADS)

Uegaki, Shin; Yoshida, Akihiro; Hosoito, Nobuyoshi

2015-03-01

We investigated induced spin polarization of 4p conduction electrons in Cu layers of antiferromagnetically (AFM) and ferromagnetically (FM) coupled Co/Cu(111) metallic superlattices by resonant X-ray magnetic scattering at the Cu K absorption edge. Magnetic reflectivity profiles of the two superlattices were measured in the magnetic saturation state with circularly polarized synchrotron radiation X-rays at 8985 eV. Depth profiles of the resonant magnetic scattering length of Cu, which corresponds to the induced spin polarization of Cu, were evaluated in the two Co/Cu superlattices by analyzing the observed magnetic reflectivity profiles. We demonstrated that the spin polarization induced in the Cu layer was distributed around the Co/Cu interfaces with an attenuation length of several Å in both AFM and FM coupled superlattices. The uniform component, which exists in Au layers of Fe/Au(001) superlattices, was not found in the depth distribution of induced magnetic polarization in the Cu layers of Co/Cu(111) superlattices.

Evidence of significant covalent bonding in Au(CN)(2)(-).

PubMed

Wang, Xue-Bin; Wang, Yi-Lei; Yang, Jie; Xing, Xiao-Peng; Li, Jun; Wang, Lai-Sheng

2009-11-18

The Au(CN)(2)(-) ion is the most stable Au compound known for centuries, yet a detailed understanding of its chemical bonding is still lacking. Here we report direct experimental evidence of significant covalent bonding character in the Au-C bonds in Au(CN)(2)(-) using photoelectron spectroscopy and comparisons with its lighter congeners, Ag(CN)(2)(-) and Cu(CN)(2)(-). Vibrational progressions in the Au-C stretching mode were observed for all detachment transitions for Au(CN)(2)(-), in contrast to the atomic-like transitions for Cu(CN)(2)(-), revealing the Au-C covalent bonding character. In addition, rich electronic structural information was obtained for Au(CN)(2)(-) by employing 118 nm detachment photons. Density functional theory and high-level ab initio calculations were carried out to understand the photoelectron spectra and obtain insight into the nature of the chemical bonding in the M(CN)(2)(-) complexes. Significant covalent character in the Au-C bonding due to the strong relativistic effects was revealed in Au(CN)(2)(-), consistent with its high stability.

CuPc/Au(1 1 0): Determination of the azimuthal alignment by a combination of angle-resolved photoemission and density functional theory

PubMed Central

Lüftner, Daniel; Milko, Matus; Huppmann, Sophia; Scholz, Markus; Ngyuen, Nam; Wießner, Michael; Schöll, Achim; Reinert, Friedrich; Puschnig, Peter

2014-01-01

Here we report on a combined experimental and theoretical study on the structural and electronic properties of a monolayer of Copper-Phthalocyanine (CuPc) on the Au(1 1 0) surface. Low-energy electron diffraction reveals a commensurate overlayer unit cell containing one adsorbate species. The azimuthal alignment of the CuPc molecule is revealed by comparing experimental constant binding energy (kxky)-maps using angle-resolved photoelectron spectroscopy with theoretical momentum maps of the free molecule's highest occupied molecular orbital (HOMO). This structural information is confirmed by total energy calculations within the framework of van-der-Waals corrected density functional theory. The electronic structure is further analyzed by computing the molecule-projected density of states, using both a semi-local and a hybrid exchange-correlation functional. In agreement with experiment, the HOMO is located about 1.2 eV below the Fermi-level, while there is no significant charge transfer into the molecule and the CuPc LUMO remains unoccupied on the Au(1 1 0) surface. PMID:25284953

The Shear Strength and Fracture Behavior of Sn-Ag- xSb Solder Joints with Au/Ni-P/Cu UBM

NASA Astrophysics Data System (ADS)

Lee, Hwa-Teng; Hu, Shuen-Yuan; Hong, Ting-Fu; Chen, Yin-Fa

2008-06-01

This study investigates the effects of Sb addition on the shear strength and fracture behavior of Sn-Ag-based solders with Au/Ni-P/Cu underbump metallization (UBM) substrates. Sn-3Ag- xSb ternary alloy solder joints were prepared by adding 0 wt.% to 10 wt.% Sb to a Sn-3.5Ag alloy and joining them with Au/Ni-P/Cu UBM substrates. The solder joints were isothermally stored at 150°C for up to 625 h to study their microstructure and interfacial reaction with the UBM. Single-lap shear tests were conducted to evaluate the mechanical properties, thermal resistance, and failure behavior. The results show that UBM effectively suppressed intermetallic compound (IMC) formation and growth during isothermal storage. The Sb addition helped to refine the Ag3Sn compounds, further improving the shear strength and thermal resistance of the solders. The fracture behavior evolved from solder mode toward the mixed mode and finally to the IMC mode with increasing added Sb and isothermal storage time. However, SnSb compounds were found in the solder with 10 wt.% Sb; they may cause mechanical degradation of the solder after long-term isothermal storage.

Induced accumulation of Au, Ag and Cu in Brassica napus grown in a mine tailings with the inoculation of Aspergillus niger and the application of two chemical compounds.

PubMed

González-Valdez, Eduardo; Alarcón, Alejandro; Ferrera-Cerrato, Ronald; Vega-Carrillo, Héctor René; Maldonado-Vega, María; Salas-Luévano, Miguel Ángel; Argumedo-Delira, Rosalba

2018-06-15

This study evaluated the ability of Brassica napus for extracting gold (Au), silver (Ag) and copper (Cu) from a mine tailings, with the inoculation of two Aspergillus niger strains, and the application of ammonium thiocyanate (NH 4 SCN) or ammonium thiosulfate [(NH 4 ) 2 S 2 O 3 ]. After seven weeks of growth inoculated or non-inoculated plants were applied with 1 or 2 g kg -1 of either NH 4 SCN or (NH 4 ) 2 S 2 O 3 , respectively. Eight days after the application of the chemical compounds, plants were harvested for determining the total dry biomass, and the content of Au, Ag, and Cu in plant organs. Application of (NH 4 ) 2 S 2 O 3 or NH 4 SCN resulted in enhanced Au-accumulation in stems (447% and 507%, respectively), while either (NH 4 ) 2 S 2 O 3 +Aspergillus, or NH 4 SCN increased the Au-accumulation in roots (198.5% and 404%, respectively) when compared to the control. Treatments with (NH 4 ) 2 S 2 O 3 or (NH 4 ) 2 S 2 O 3 +Aspergillus significantly increased (P ≤ 0.001) the accumulation of Ag in leaves (677% and 1376%, respectively), while NH 4 SCN + Aspergillus, and (NH 4 ) 2 S 2 O 3 enhanced the accumulation in stems (7153% and 6717.5%). The Ag-accumulation in roots was stimulated by NH 4 SCN+ Aspergillus, and (NH 4 ) 2 S 2 O 3 + Aspergillus (132.5% and 178%, respectively), when compared to the control. The combination of NH 4 SCN+Aspergillus significantly enhanced the Cu-accumulation in leaves (228%); whereas NH 4 SCN+ Aspergillus, or (NH 4 ) 2 S 2 O 3 + Aspergillus resulted in greater accumulation of Cu in stems (1233.5% and 1580%, respectively) than the control. Results suggest that either NH 4 SCN or (NH 4 ) 2 S 2 O 3 (with or without Aspergillus) improved the accumulation of Au and Ag by B. napus. Accumulation of Au and Ag in plant organs overpassed the hyperaccumulation criterion (> 1 mg kg -1 of plant biomass); whereas Cu-accumulation in stems and roots also overpassed such criterion (> 1000 mg kg -1 ) by applying

Molecular dynamics and binding selectivity of nucleotides and polynucleotide substrates with EIF2C2/Ago2 PAZ domain.

PubMed

Kandeel, Mahmoud; Kitade, Yukio

2018-02-01

RNA interference (RNAi) constitutes a major target in drug discovery. Recently, we reported that the Argonaute protein 2 (Ago2) PAZ domain selectively binds with all ribonucleotides except adenine and poorly recognizes deoxyribonucleotides. The binding properties of the PAZ domain with polynucleotides and the molecular mechanisms of substrates' selectivity remains unclear. In this study, the binding potencies of polynucleotides and the associated conformational and dynamic changes in PAZ domain are investigated. Coinciding with nucleotides' binding profile with the PAZ domain, polyuridylate (PolyU) and polycytidylate (PolyC) were potent binders. However, K dPolyU and K dPolyC were 15.8 and 9.3μM, respectively. In contrast, polyadenylate (PolyA) binding was not detectable. Molecular dynamics (MD) simulation revealed the highest change in root mean square deviation (RMSD) with ApoPAZ or PAZ domain bound with experimentally approved, low affinity substrates, whereas stronger binding substrates such as UMP or PolyU showed minimal RMSD changes. The loop between α3 and β5 in the β-hairpin subdomain showed the most responsive change in RMSD, being highly movable in the ApoPAZ and PAZ-AMP complex. Favorable substrate recognition was associate with moderate change in secondary structure content. In conclusion, the PAZ domain retains differential substrate selectivity associated with corresponding dynamic and structural changes upon binding. Copyright © 2017 Elsevier B.V. All rights reserved.

Spectroscopy, electrochemistry and antiproliferative properties of Au(iii), Pt(ii) and Cu(ii) complexes bearing modified 2,2':6',2''-terpyridine ligands.

PubMed

Maroń, Anna; Czerwińska, Katarzyna; Machura, Barbara; Raposo, Luis; Roma-Rodrigues, Catarina; Fernandes, Alexandra R; Małecki, Jan G; Szlapa-Kula, Agata; Kula, Slawomir; Krompiec, Stanisław

2018-05-08

Structural, spectroscopic and electrochemical properties of six complexes [AuCl(L1)](PF6)2·CH3CN (1), [AuCl(L2)](PF6)2 (2), [PtCl(L1)](BPh4)·CH3CN (3), [PtCl(L2)](SO3CF3) (4), [CuCl2(L1)] (5) and [CuCl2(L2)]·CH3CN (6) with modified 2,2':6',2''-terpyridine ligands, 4'-(4-methoxyphenyl)-2,2':6',2''-terpyridine (L1) and 4'-(4-methoxynaphthalen-1-yl)-2,2':6',2''-terpyridine (L2) were thoroughly investigated and a significant role of the substituent (4-methoxyphenyl or 4-methoxynaphthalen-1-yl) and the metal center was demonstrated. The naphthyl-based substituent was found to increase the emission quantum yield of the luminescent Au(iii) and Pt(ii) complexes. Furthermore, the antiproliferative potential of the reported complexes was examined towards human colorectal (HCT116) and ovarian (A2780) carcinoma cell lines as well as towards normal human fibroblasts. The Au(iii) complex 2 and Cu(ii) complex 5 were found to have a higher antiproliferative effect on HCT116 colorectal and A2780 ovarian carcinoma cells when compared with the Pt(ii) complex with the same ligand (4). The order of cytotoxicity in both cell lines is 2 > 6 > 1 > 3 > 4. Complex 2 seems to be more cytotoxic towards HCT116 and A2780 cancer cell lines with IC50 values 300× and 130× higher in normal human fibroblasts compared to the respective cancer cells. The viability loss induced by the complexes agrees with Hoechst 33258 staining and the typical morphological apoptotic characteristics like chromatin condensation and nuclear fragmentation and flow cytometry assay. The induction of apoptosis correlates with the induction of reactive oxygen species (ROS). Fluorescence microscopy analysis indicates that after 3 h of incubation, complexes 1-4 are localized inside HCT116 cells and the high levels of internalization correlate with their cytotoxicity.

Study of Dielectric Behavior and Charge Conduction Mechanism of Poly(Vinyl Alcohol) (PVA)-Copper (Cu) and Gold (Au) Nanocomposites as a Bio-resorbable Material for Organic Electronics

NASA Astrophysics Data System (ADS)

Mahendia, Suman; Goyal, Parveen Kumar; Tomar, Anil Kumar; Chahal, Rishi Pal; Kumar, Shyam

2016-10-01

Poly(vinyl alcohol) (PVA) embedded with varying concentrations of chemically synthesized copper (Cu) and gold (Au) nanoparticles (NPs) were prepared using ex situ sol-gel casting method. The addition of almost the same concentration of CuNPs in PVA improves the conducting properties, while that of AuNPs improves the dielectric nature of composite films. It has been found that addition of AuNPs up to ˜0.4 wt.% concentration enhaneces the capacitive nature due to the formation of small Coulomb tunneling knots as internal capacitors. The dielectric studies suggest the Maxwell-Wagner interfacial polarization as the dominant dielectric relaxation process, whereas the I- V characteristics indicate bulk limited Poole-Frenkel emission at high voltages as the dominant charge transport mechanism operating at room temperature in all specimens. These novel features lead to the conclusion that addition of a small quantity of metal nanoparticles can help tune the properties of PVA for desired applications in bio-compatible polymer-based organic electronic devices.

Role of evaporitic sulfates in iron skarn mineralization: a fluid inclusion and sulfur isotope study from the Xishimen deposit, Handan-Xingtai district, North China Craton

NASA Astrophysics Data System (ADS)

Wen, Guang; Bi, Shi-Jian; Li, Jian-Wei

2017-04-01

The Xishimen iron skarn deposit in the Handan-Xingtai district, North China Craton, contains 256 Mt @ 43 % Fe (up to 65 %). The mineralization is dominated by massive magnetite ore along the contact zone between the early Cretaceous Xishimen diorite stock and middle Ordovician dolomite and dolomitic limestones with numerous intercalations of evaporitic beds. Minor lenticular magnetite-dominated bodies also occur in the carbonate rocks proximal to the diorite stock. Hydrothermal alteration is characterized by extensive albitization within the diorite stock and extreme development of magnesian skarn along the contact zone consisting of diopside, forsterite, serpentine, tremolite, phlogopite, and talc. Magmatic quartz and amphibole from the diorite and hydrothermal diopside from the skarns contain abundant primary or pseudosecondary fluid inclusions, most of which have multiple daughter minerals dominated by halite, sylvite, and opaque phases. Scanning electron microscopy (SEM) and laser Raman spectrometry confirm that pyrrhotite is the predominant opaque phase in most fluid inclusions, in both the magmatic and skarn minerals. These fluid inclusions have total homogenization temperatures of 416-620 °C and calculated salinities of 42.4-74.5 wt% NaCl equiv. The fluid inclusion data thus document a high-temperature, high-salinity, ferrous iron-rich, reducing fluid exsolved from a cooling magma likely represented by the Xishimen diorite stock. Pyrite from the iron ore has δ34S values ranging from 14.0 to 18.6 ‰, which are significantly higher than typical magmatic values (δ34S = 0 ± 5 ‰). The sulfur isotope data thus indicate an external source for the sulfur, most likely from the evaporitic beds in the Ordovician carbonate sequences that have δ34S values of 24 to 29 ‰. We suggest that sulfates from the evaporitic beds have played a critically important role by oxidizing ferrous iron in the magmatic-hydrothermal fluid, leading to precipitation of massive

Characterization of Cu buffer layers for growth of L10-FeNi thin films

NASA Astrophysics Data System (ADS)

Mizuguchi, M.; Sekiya, S.; Takanashi, K.

2010-05-01

A Cu(001) layer was fabricated on a Au(001) layer to investigate the use of Cu as a buffer layer for growing L10-FeNi thin films. The epitaxial growth of a Cu buffer layer was observed using reflection high-energy electron diffraction. The flatness of the layer improved drastically with an increase in the substrate temperature although the layer was an alloy (AuCu3). An FeNi thin film was epitaxially grown on the AuCu3 buffer layer by alternate monatomic layer deposition and the formation of an L10-FeNi ordered alloy was expected. The AuCu3 buffer layer is thus a promising candidate material for the growth of L10-FeNi thin films.

Geochemistry and fluid characteristics of the Dalli porphyry Cu-Au deposit, Central Iran

NASA Astrophysics Data System (ADS)

Zarasvandi, Alireza; Rezaei, Mohsen; Raith, Johann; Lentz, David; Azimzadeh, Amir-Mortaza; Pourkaseb, Hooshang

2015-11-01

The Miocene Dalli porphyry Cu-Au deposit in the central part of Urumieh-Dokhtar magmatic arc is the first reported Au-rich porphyry Cu deposit in the Zagros orogenic belt. The Cu-Au mineralization is mainly hosted in diorite and quartz diorite intrusions, presenting as numerous veinlets in the altered wall rocks, with potassic, phyllic, and propylitic alteration developed. Based on the mineral assemblages and crosscutting relations of veinlets, hydrothermal mineralization-alteration occurred in at least three stages, characterized by veinlets of (1) Qtz + Kfs + Mag ± Ccp, (2) Qtz + Py + Ccp ± Bn ± Cv ± Cc and, (3) Qtz + Chl + Bt. The ore-bearing intrusions exhibit typical geochemical characteristics of subduction zone magmas, including LREE fractionated pattern, strong enrichment in LILE (Cs, Rb, Ba, Pb, and U), and depletion of HFSE, with marked negative Ti and Nb anomalies. The adakite-like ore-hosting porphyry intrusions are characterized by a systematic gradual decreasing and increasing of Y and Eu/Eu∗ with increasing SiO2 content, respectively. Moreover, they exhibit a significant increasing trend of Sr/Y with decreasing of Y, which indicates progressive hornblende fractionation and suppression of plagioclase fractionation during the evolution toward high water content of parental magma. A relatively flat HREE pattern with low Dyn/Ybn and Nb/Ta values may represent that amphibole played a more important role than garnet in the generation of the adakitic melts in the thickened lower crust. Based on the phase assemblages confirmed by detailed laser Raman spectroscopy analyses and proportion of solid, liquid, and gaseous components, five types of fluid inclusions were recognized, which are categorized as; (1) liquid-rich two phase (liquidH2O + vaporH2O) (IIA), (2) vapor-rich two phase (vaporH2O/CO2 + liquidH2O) (IIB), (3) high saline simple fluids (IIIA; liquidH2O + vaporH2O + Hl), (4) high saline opaque mineral-bearing fluids (IIIB; liquidH2O + vaporH2O

[Quantitative surface analysis of Pt-Co, Cu-Au and Cu-Ag alloy films by XPS and AES].

PubMed

Li, Lian-Zhong; Zhuo, Shang-Jun; Shen, Ru-Xiang; Qian, Rong; Gao, Jie

2013-11-01

In order to improve the quantitative analysis accuracy of AES, We associated XPS with AES and studied the method to reduce the error of AES quantitative analysis, selected Pt-Co, Cu-Au and Cu-Ag binary alloy thin-films as the samples, used XPS to correct AES quantitative analysis results by changing the auger sensitivity factors to make their quantitative analysis results more similar. Then we verified the accuracy of the quantitative analysis of AES when using the revised sensitivity factors by other samples with different composition ratio, and the results showed that the corrected relative sensitivity factors can reduce the error in quantitative analysis of AES to less than 10%. Peak defining is difficult in the form of the integral spectrum of AES analysis since choosing the starting point and ending point when determining the characteristic auger peak intensity area with great uncertainty, and to make analysis easier, we also processed data in the form of the differential spectrum, made quantitative analysis on the basis of peak to peak height instead of peak area, corrected the relative sensitivity factors, and verified the accuracy of quantitative analysis by the other samples with different composition ratio. The result showed that the analytical error in quantitative analysis of AES reduced to less than 9%. It showed that the accuracy of AES quantitative analysis can be highly improved by the way of associating XPS with AES to correct the auger sensitivity factors since the matrix effects are taken into account. Good consistency was presented, proving the feasibility of this method.

Platinum-group element geochemistry of the Forest Reef Volcanics, southeastern Australia: Implications for porphyry Au-Cu mineralisation

NASA Astrophysics Data System (ADS)

Lowczak, Jessica N.; Campbell, Ian H.; Cocker, Helen; Park, Jung-Woo; Cooke, David R.

2018-01-01

Platinum-group element concentrations in felsic to intermediate rocks from the Forest Reef Volcanics, Cadia-Neville region, southeastern Australia have been analysed by the Ni-S fire assay-isotope dilution method. The Forest Reef Volcanics are shoshonitic to calc-alkaline in composition and fractionated to produce a wide range of compositions, with MgO varying between 9.7 and 1.8 wt.%. The interest in this suite is that it is coeval with Au-Cu porphyry-style mineralisation in the Cadia mineral district. This study uses PGE geochemistry to determine the timing of sulfide saturation, relative to volatile (ore-fluid) saturation, in the magma that gave rise to the Forest Reef Volcanics and, in turn, to assess how this timing affected the mineralisation potential of the evolving magmatic system. The Forest Reef Volcanics can be subdivided, on the basis of their contrasting PGE geochemistry, into high-Mg (>6.8 wt.% MgO) and low-Mg suites (≤6.8 wt.% MgO). Platinum, Pd and Re concentrations increase in the high-Mg samples, whereas Ir and Ru decrease and Rh concentrations remain steady, with decreasing MgO. The coupled Ir, Ru and Rh depletion is attributed to the partitioning of these elements into magnetite. The rate of Pt and Pd enrichment is not possible by closed-system fractional crystallisation alone, which suggests that the parent magma was replenished by a Pt-Pd-rich melt. In contrast, the PGE concentrations in the low-Mg samples decrease with decreasing MgO indicating the onset of sulfide saturation at 6.8 wt.% MgO, which is confirmed by the presence of spheroidal sulfide inclusions in liquidus crystals (i.e. clinopyroxene, plagioclase, magnetite). The rate of Pd depletion is appreciably less than for any other sulfide saturated felsic system for which data are available. This requires either that the amount of sulfide melt to have precipitated was unusually low, or that the rate of Pd depletion was limited by the mass of silicate melt the sulfide melt reached

Late Paleozoic tectonic evolution and concentrated mineralization in Balkhash and West Junggar, western part of the Central Asian Orogenic Belt

NASA Astrophysics Data System (ADS)

Dong, Shuwen; Chen, Xuanhua; Chen, Zhengle

2016-04-01

course thermo-history of the minearl deposits from their formation in the deep to the exhumation in the surface. It reveals the arc-related granitic magmatism and the metallogeneses of skarn Cu, porphyry Cu-Mo, quartz-vein/greisen W-Mo, and orogenic Au in Late Paleozoic, the medium-temperature regional cooling in Late Paleozoic and Early Mesozoic, and the low-temperature exhumation of the deposits in Mesozoic. The timing, combined with geochemistry of granitoids, suggests a transition of tectonic environment from syn-collision and volcanic arc in Late Carboniferous to post-collision extension in Early Permian, and the concentrated mineralization of Cu, Mo, rare metals, and Au during this tectonic transition. The complete metallogenic series for the concentrated mineralization are from skarn and porphyry Cu-Mo deposits to rare metal and gold deposits. Key words: Late Paleozoic; Tectonic evolution; Concentrated mineralization; Balkhash-Junggar tectono-metallogenic belt; Central Asian Orogenic Belt

Proterozoic low-Ti iron-oxide deposits in New York and New Jersey: relation to Fe-oxide (Cu-U-Au-rare earth element) deposits and tectonic implications

USGS Publications Warehouse

Foose, M.P.; McLelland, J.M.

1995-01-01

Low-Ti iron-oxide deposits in exposed Grenville-age rocks of New York and New Jersey belong to a distinct class of iron-oxide (Cu-U-Au-rare earth element [REE]) deposits that includes similar iron deposits in southeastern Missouri and the Kiruna district of Sweden, the giant Olympic Dam U-Cu-Au-Ag deposit (Australia), and the Bayan Obo REE-Nb deposit (China). Most of the New York-New Jersey deposits exhibit features consistent with a hydrothermal origin and define a regionally significant metallogenic event that provides important clues to the evolution of this part of the Grenville orogen. In the Adirondacks, the tectonic setting of these deposits is consistent with postorogenic uplift and extensive crustal melting at 1070-1050 Ma that was accompanied by late tectonic to posttectonic deposition of iron. -Authors

Sulfur isotope study of the Velardeña skarn (Zn-Pb), Durango, Mexico

NASA Astrophysics Data System (ADS)

Jimenez, A.

2012-04-01

Sulfur isotope study of the Velardeña skarn (Zn-Pb), Durango, Mexico Abigail Jimenez-Franco1*, Pura Alfonso Abella2, Carles Canet3, Eduardo González-Partida4 1 Posgrado en Ciencias de la Tierra, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, 04510 México D.F., Mexico 2 Departament d'Enginyeria Minera i Recursos Naturals, Universitat Politècnica de Catalunya, Av de Les Bases de Manresa 61-73, 08242 Manresa. 3Instituto de Geofísica, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, 04510 México D.F., Mexico 4Centro de Geociencias, Universidad Nacional Autónoma de México, Campus Juriquilla, Boulevard Juriquilla 3001, 76230 Santiago de Querétaro, Qro., Mexico The Velardeña mining district is located in north-eastern part of the state of Durango, in northern of Mexico. The ore deposit is a lead-zinc, garnet-rich skarn developed at the contact between granite porphyry dikes (Eocene) and well-laminated limestones with interbedded chert (Albian-Cenomanian). A study of sulfur isotopes has been carried out in various sulfide minerals of the ores of Velardeña, in order to: (a) constrain the possible sources of sulfur and, therefore, better understand the sulfide mineralizing processes, and (b) to estimate the temperature of the ore-forming stage of the skarn. Sulfur isotope analyses were performed in 21 pure fractions of sulfide minerals of the ore mineralization (pyrite, chalcopyrite, sphalerite and galena). The mineral separation was performed using a series of sieves, and the purity of the samples was verified under a binocular microscope. Isotopic analyses were done on a Finnigan MAT Delta C flow elemental analyzer coupled to a TC-EA, according with the method of Giesemann et al. (1974). The δ34S values of the analyzed sulfides range mostly between -0.6 and +2.6 ‰ (relative to the CDT standard). These values are indicative of a magmatic source of sulfur. A single analysis falls

High-mass heterogeneous cluster formation by ion bombardment of the ternary alloy Au 7Cu 5Al 4

DOE PAGES

Zinovev, Alexander V.; King, Bruce V.; Veryovkin, Igor V.; ...

2016-02-04

The ternary alloy Au 7Cu 5Al 4 was irradiated with 0.1–10 keV Ar + and the surface composition analyzed using laser sputter neutral mass spectrometry. Ejected clusters containing up to seven atoms, with masses up to 2000 amu, were observed. By monitoring the signals from sputtered clusters, the surface composition of the alloy was seen to change with 100 eV Ar + dose, reaching equilibrium after 10 nm of the surface was eroded, in agreement with TRIDYN simulation and indicating that the changes were due to preferential sputtering of Al and Cu. Ejected gold containing clusters were found to increasemore » markedly in intensity while aluminum containing clusters decreased in intensity as a result of Ar sputtering. Such an effect was most pronounced for low energy (<1 keV) Ar + sputtering and was consistent with TRIDYN simulations of the depth profiling. As a result, the component sputter yields from the ternary alloy were consistent with previous binary alloy measurements but showed greater Cu surface concentrations than expected from TRIDYN simulations.« less

Catalytic activity of nanostructured Au: Scale effects versus bimetallic/bifunctional effects in low-temperature CO oxidation on nanoporous Au

PubMed Central

Wang, Lu-Cun; Zhong, Yi; Jin, Haijun; Widmann, Daniel; Weissmüller, Jörg

2013-01-01

Summary The catalytic properties of nanostructured Au and their physical origin were investigated by using the low-temperature CO oxidation as a test reaction. In order to distinguish between structural effects (structure–activity correlations) and bimetallic/bifunctional effects, unsupported nanoporous gold (NPG) samples prepared from different Au alloys (AuAg, AuCu) by selective leaching of a less noble metal (Ag, Cu) were employed, whose structure (surface area, ligament size) as well as their residual amount of the second metal were systematically varied by applying different potentials for dealloying. The structural and chemical properties before and after 1000 min reaction were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The catalytic behavior was evaluated by kinetic measurements in a conventional microreactor and by dynamic measurements in a temporal analysis of products (TAP) reactor. The data reveal a clear influence of the surface contents of residual Ag and Cu species on both O2 activation and catalytic activity, while correlations between activity and structural parameters such as surface area or ligament/crystallite size are less evident. Consequences for the mechanistic understanding and the role of the nanostructure in these NPG catalysts are discussed. PMID:23503603

From the ternary Eu(Au/In) 2 and EuAu 4(Au/In) 2 with remarkable Au/In distributions to a new structure type: The gold-rich Eu 5Au 16(Au/In) 6 structure

DOE PAGES

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

2015-08-13

The ternary Eu(Au/In) 2 (EuAu 0.46In 1.54 (2)) (I), EuAu 4(Au/In) 2 (EuAu 4+xIn 2–x with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu 5Au 16(Au/In) 6 (Eu 5Au 17.29In 4.71(3)) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu 2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl 4Mo 2-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 ofmore » an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squared Au 8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu 5Au 16(Au/In) 6 (Eu 5Au 17.29In 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 EuAu 2–“EuAu 4In 2”. The site preferences of the disordered Au/In positions in II were investigated for different hypothetical “EuAu 4(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 “EuAu 5In” and “EuAu 4In 2” 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

From the ternary Eu(Au/In) 2 and EuAu 4(Au/In) 2 with remarkable Au/In distributions to a new structure type: The gold-rich Eu 5Au 16(Au/In) 6 structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

The ternary Eu(Au/In) 2 (EuAu 0.46In 1.54 (2)) (I), EuAu 4(Au/In) 2 (EuAu 4+xIn 2–x with x = 0.75(2) (II), 0.93(2), and 1.03(2)), and Eu 5Au 16(Au/In) 6 (Eu 5Au 17.29In 4.71(3)) (III) have been synthesized, and their structures were characterized by single-crystal X-ray diffraction. I and II crystallize with the CeCu 2-type (Pearson Symbol oI12; Imma; Z = 4; a = 4.9018(4) Å; b = 7.8237(5) Å; c = 8.4457(5) Å) and the YbAl 4Mo 2-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 ofmore » an Au/In-mixed diamond-related host lattice encapsulating Eu atoms, while the structure of II features ribbons of distorted, squared Au 8 prisms enclosing Eu, Au, and In atoms. Combination of these structural motifs leads to a new structure type as observed for Eu 5Au 16(Au/In) 6 (Eu 5Au 17.29In 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 EuAu 2–“EuAu 4In 2”. The site preferences of the disordered Au/In positions in II were investigated for different hypothetical “EuAu 4(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 “EuAu 5In” and “EuAu 4In 2” 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

Development of casting investment preventing blackening of noble metal alloys part 1. Application of developed investment for Ag-Pd-Cu-Au alloy.

PubMed

Kakuta, Kiyoshi; Nakai, Akira; Goto, Shin-ichi; Wakamatsu, Yasushi; Yara, Atushi; Miyagawa, Yukio; Ogura, Hideo

2003-03-01

The objective of this study is to develop a casting investment that prevents the blackening of the cast surface of noble metal alloys. The experimental investments were prepared using a gypsum-bonded investment in which the metallic powders such as boron (B), silicon (Si), aluminum (Al) and titanium (Ti) were added as oxidizing agents. An Ag-Pd-Cu-Au alloy was cast into the mold made of the prepared investment. The effect of the addition of each metal powder was evaluated from the color difference between the as-cast surface and the polished surface of the cast specimen. The color of the as-cast surface approached that of the polished surface with increasing B and Al content. A lower mean value in the color difference was obtained at 0.25-1.00 mass% B content. B and Al are useful as an additive in a gypsum-bonded investment to prevent the blackening of an Ag-Pd-Cu-Au alloy. The effects of Si and Ti powder addition could not be found.

Structure functions in decomposing CuRh systems

NASA Astrophysics Data System (ADS)

Prem, M.; Blaschko, O.; Rosta, L.

1997-02-01

The time evolution of a CuRh alloy quenched within the miscibility gap is investigated by small and wide angle neutron scattering techniques. Near fundamental Bragg reflections diffuse satellites arising from a lattice parameter modulation induced by the precipitation pattern are investigated. The results show that in CuRh the precipitation morphology and its time evolution are quite different from decomposition characteristics recently observed in the system AuPt. The results are discussed and related to the larger lattice misfit present in CuRh in comparison to AuPt.

ZnO/CuO/M (M = Ag, Au) Hierarchical Nanostructure by Successive Photoreduction Process for Solar Hydrogen Generation.

PubMed

Kwon, Jinhyeong; Cho, Hyunmin; Jung, Jinwook; Lee, Habeom; Hong, Sukjoon; Yeo, Junyeob; Han, Seungyong; Ko, Seung Hwan

2018-05-12

To date, solar energy generation devices have been widely studied to meet a clean and sustainable energy source. Among them, water splitting photoelectrochemical cell is regarded as a promising energy generation way for splitting water molecules and generating hydrogen by sunlight. While many nanostructured metal oxides are considered as a candidate, most of them have an improper bandgap structure lowering energy transition efficiency. Herein, we introduce a novel wet-based, successive photoreduction process that can improve charge transfer efficiency by surface plasmon effect for a solar-driven water splitting device. The proposed process enables to fabricate ZnO/CuO/Ag or ZnO/CuO/Au hierarchical nanostructure, having an enhanced electrical, optical, photoelectrochemical property. The fabricated hierarchical nanostructures are demonstrated as a photocathode in the photoelectrochemical cell and characterized by using various analytic tools.

ZnO/CuO/M (M = Ag, Au) Hierarchical Nanostructure by Successive Photoreduction Process for Solar Hydrogen Generation

PubMed Central

Kwon, Jinhyeong; Cho, Hyunmin; Jung, Jinwook; Lee, Habeom; Han, Seungyong

2018-01-01

To date, solar energy generation devices have been widely studied to meet a clean and sustainable energy source. Among them, water splitting photoelectrochemical cell is regarded as a promising energy generation way for splitting water molecules and generating hydrogen by sunlight. While many nanostructured metal oxides are considered as a candidate, most of them have an improper bandgap structure lowering energy transition efficiency. Herein, we introduce a novel wet-based, successive photoreduction process that can improve charge transfer efficiency by surface plasmon effect for a solar-driven water splitting device. The proposed process enables to fabricate ZnO/CuO/Ag or ZnO/CuO/Au hierarchical nanostructure, having an enhanced electrical, optical, photoelectrochemical property. The fabricated hierarchical nanostructures are demonstrated as a photocathode in the photoelectrochemical cell and characterized by using various analytic tools. PMID:29757225

Pentacene on Au(1 1 1), Ag(1 1 1) and Cu(1 1 1): From physisorption to chemisorption.

PubMed

Lu, Meng-Chao; Wang, Rong-Bin; Yang, Ao; Duhm, Steffen

2016-03-09

We measured the electronic and the molecular surface structure of pentacene deposited on the (1 1 1)-surfaces of coinage metals by means of ultraviolet photoelectron spectroscopy (UPS) and low-energy electron diffraction (LEED). Pentacene is almost flat-lying in monolayers on all three substrates and highly ordered on Au(1 1 1) and on Cu(1 1 1). On Ag(1 1 1), however, weak chemisorption leads to almost disordered monolayers, both, at room temperature and at 78 K. On Cu(1 1 1) pentacene is strongly chemisorbed and the lowest unoccupied molecular orbital becomes observable in UPS by a charge transfer from the substrate. On Ag(1 1 1) and Cu(1 1 1) multilayers adopt a tilted orientation and a high degree of crystallinity. On Au(1 1 1), most likely, also in multilayers the molecular short and long axes are parallel to the substrate, leading to a distinctively different electronic structure than on Ag(1 1 1) and Cu(1 1 1). Overall, it could be demonstrated that the substrate not only determines the geometric and electronic characteristics of molecular monolayer films but also plays a crucial role for multilayer film growth.

An orientation soil survey at the Pebble Cu-Au-Mo porphyry deposit, Alaska

USGS Publications Warehouse

Smith, Steven M.; Eppinger, Robert G.; Fey, David L.; Kelley, Karen D.; Giles, S.A.

2009-01-01

Soil samples were collected in 2007 and 2008 along three traverses across the giant Pebble Cu-Au-Mo porphyry deposit. Within each soil pit, four subsamples were collected following recommended protocols for each of ten commonly-used and proprietary leach/digestion techniques. The significance of geochemical patterns generated by these techniques was classified by visual inspection of plots showing individual element concentration by each analytical method along the 2007 traverse. A simple matrix by element versus method, populated with a value based on the significance classification, provides a method for ranking the utility of methods and elements at this deposit. The interpretation of a complex multi-element dataset derived from multiple analytical techniques is challenging. An example of vanadium results from a single leach technique is used to illustrate the several possible interpretations of the data.

Measurement of antiproton annihilation on Cu, Ag and Au with emulsion films

NASA Astrophysics Data System (ADS)

Aghion, S.; Amsler, C.; Ariga, A.; Ariga, T.; Bonomi, G.; Bräunig, P.; Brusa, R. S.; Cabaret, L.; Caccia, M.; Caravita, R.; Castelli, F.; Cerchiari, G.; Comparat, D.; Consolati, G.; Demetrio, A.; Di Noto, L.; Doser, M.; Ereditato, A.; Evans, C.; Ferragut, R.; Fesel, J.; Fontana, A.; Gerber, S.; Giammarchi, M.; Gligorova, A.; Guatieri, F.; Haider, S.; Hinterberger, A.; Holmestad, H.; Huse, T.; Kawada, J.; Kellerbauer, A.; Kimura, M.; Krasnický, D.; Lagomarsino, V.; Lansonneur, P.; Lebrun, P.; Malbrunot, C.; Mariazzi, S.; Matveev, V.; Mazzotta, Z.; Müller, S. R.; Nebbia, G.; Nedelec, P.; Oberthaler, M.; Pacifico, N.; Pagano, D.; Penasa, L.; Petracek, V.; Pistillo, C.; Prelz, F.; Prevedelli, M.; Ravelli, L.; Rienaecker, B.; RØhne, O. M.; Rotondi, A.; Sacerdoti, M.; Sandaker, H.; Santoro, R.; Scampoli, P.; Simon, M.; Smestad, L.; Sorrentino, F.; Testera, G.; Tietje, I. C.; Vamosi, S.; Vladymyrov, M.; Widmann, E.; Yzombard, P.; Zimmer, C.; Zmeskal, J.; Zurlo, N.

2017-04-01

The characteristics of low energy antiproton annihilations on nuclei (e.g. hadronization and product multiplicities) are not well known, and Monte Carlo simulation packages that use different models provide different descriptions of the annihilation events. In this study, we measured the particle multiplicities resulting from antiproton annihilations on nuclei. The results were compared with predictions obtained using different models in the simulation tools GEANT4 and FLUKA. For this study, we exposed thin targets (Cu, Ag and Au) to a very low energy antiproton beam from CERN's Antiproton Decelerator, exploiting the secondary beamline available in the AEgIS experimental zone. The antiproton annihilation products were detected using emulsion films developed at the Laboratory of High Energy Physics in Bern, where they were analysed at the automatic microscope facility. The fragment multiplicity measured in this study is in good agreement with results obtained with FLUKA simulations for both minimally and heavily ionizing particles.

Structural evolution of atomically precise thiolated bimetallic [Au(12+n)Cu₃₂(SR)(30+n)]⁴⁻ (n = 0, 2, 4, 6) nanoclusters.

PubMed

Yang, Huayan; Wang, Yu; Yan, Juanzhu; Chen, Xi; Zhang, Xin; Häkkinen, Hannu; Zheng, Nanfeng

2014-05-21

A series of all-thiol stabilized bimetallic Au-Cu nanoclusters, [Au(12+n)Cu32(SR)(30+n)](4-) (n = 0, 2, 4, 6 and SR = SPhCF3), are successfully synthesized and characterized by X-ray single-crystal analysis and density functional theory (DFT) calculations. Each cluster consists of a Keplerate two-shell Au12@Cu20 core protected by (6 - n) units of Cu2(SR)5 and n units of Cu2Au(SR)6 (n = 0, 2, 4, 6) motifs on its surface. The size and structural evolution of the clusters is atomically controlled by the Au precursors and countercations used in the syntheses. The clusters exhibit similar optical absorption properties that are not dependent on the number of surface Cu2Au(SR)6 units. Although DFT suggests an electronic structure with an 18-electron superatom shell closure, the clusters display different thermal stabilities. [Au(12+n)Cu32(SR)(30+n)](4-) clusters with n = 0 and 2 are more stable than those with n = 4 and 6. Moreover, an oxidation product of the clusters, [Au13Cu12(SR)20](4-), is structurally identified to gain insight into how the clusters are oxidized.

In silico molecular docking analysis of the human Argonaute 2 PAZ domain reveals insights into RNA interference.

PubMed

Kandeel, Mahmoud; Kitade, Yukio

2013-07-01

RNA interference (RNAi) is a critical cellular pathway activated by double stranded RNA and regulates the gene expression of target mRNA. During RNAi, the 3' end of siRNA binds with the PAZ domain, followed by release and rebinding in a cyclic manner, which deemed essential for proper gene silencing. Recently, we provided the forces underlying the recognition of small interfering RNA by PAZ in a computational study based on the structure of Drosophila Argonaute 2 (Ago2) PAZ domain. We have now reanalyzed these data within the view of the new available structures from human Argonauts. While the parameters of weak binding are correlated with higher (RNAi) in the Drosophila model, a different profile is predicted with the human Ago2 PAZ domain. On the basis of the human Ago2 PAZ models, the indicators of stronger binding as the total binding energy and the free energy were associated with better RNAi efficacy. This discrepancy might be attributable to differences in the binding site topology and the difference in the conformation of the bound nucleotides.

Computational materials design of negative effective U system in the hole-doped Delafossite of CuAlO2, AgAlO2 and AuAlO2

NASA Astrophysics Data System (ADS)

Nakanishi, Akitaka; Fukushima, Tetsuya; Uede, Hiroki; Katayama-Yoshida, Hiroshi

2015-03-01

In order to realize the super-high-TC superconductors (TC>1,000K) based on the general design rules for the negative Ueff system, we have performed computational materials design for theUeff<0 system in the hole-doped two-dimensional (2D) Delafossite CuAlO2, AgAlO2 and AuAlO2 from the first principles. We find the interesting chemical trend of TC in 2D and 3D systems; where the TC increases exponentially in the weak coupling regime (|Ueff (-0.44eV)|< W(2eV), W is the band width) for hole-doped CuFeS2, then the TC goes through a maximum when |Ueff (-4.88eV, -4.14eV)| ~ W (2.8eV, 3.5eV) for hole-doped AgAlO2 and AuAlO2, and the TC decreases with increasing |Ueff|in strong coupling regime, where |Ueff (-4.53eV)|> W(1.7eV) for hole-doped CuAlO2

Comparing Ullmann Coupling on Noble Metal Surfaces: On-Surface Polymerization of 1,3,6,8-Tetrabromopyrene on Cu(111) and Au(111).

PubMed

Pham, Tuan Anh; Song, Fei; Nguyen, Manh-Thuong; Li, Zheshen; Studener, Florian; Stöhr, Meike

2016-04-18

The on-surface polymerization of 1,3,6,8-tetrabromopyrene (Br4 Py) on Cu(111) and Au(111) surfaces under ultrahigh vacuum conditions was investigated by a combination of scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. Deposition of Br4 Py on Cu(111) held at 300 K resulted in a spontaneous debromination reaction, generating the formation of a branched coordination polymer network stabilized by C-Cu-C bonds. After annealing at 473 K, the C-Cu-C bonds were converted to covalent C-C bonds, leading to the formation of a covalently linked molecular network of short oligomers. In contrast, highly ordered self-assembled two-dimensional (2D) patterns stabilized by both Br-Br halogen and Br-H hydrogen bonds were observed upon deposition of Br4 Py on Au(111) held at 300 K. Subsequent annealing of the sample at 473 K led to a dissociation of the C-Br bonds and the formation of disordered metal-coordinated molecular networks. Further annealing at 573 K resulted in the formation of covalently linked disordered networks. Importantly, we found that the chosen substrate not only plays an important role as catalyst for the Ullmann reaction, but also influences the formation of different types of intermolecular bonds and thus, determines the final polymer network morphology. DFT calculations further support our experimental findings obtained by STM and XPS and add complementary information on the reaction pathway of Br4 Py on the different substrates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Resistive switching of Cu/Cu2O junction fabricated using simple thermal oxidation at 423 K for memristor application

NASA Astrophysics Data System (ADS)

Ani, M. H.; Helmi, F.; Herman, S. H.; Noh, S.

2018-01-01

Recently, extensive researches have been done on memristor to replace current memory storage technologies. Study on active layer of memristor mostly involving n-type semiconductor oxide such as TiO2 and ZnO. This paper highlight a simple water vapour oxidation method at 423 K to form Cu/Cu2O electronic junction as a new type of memristor. Cu2O is a p-type semiconductor oxide, was used as the active layer of memristor. Cu/Cu2O/Au memristor was fabricated by thermal oxidation of copper foil, followed by sputtering of gold. Structural, morphological and memristive properties were characterized using XRD, FESEM, and current-voltage, I-V measurement respectively. Its memristivity was indentified by pinch hysteresis loop and measurement of high resistance state (HRS) and low resistance state (LRS) of the sample. The Cu/Cu2O/Au memristor demonstrates comparable performances to previous studies using other methods.

Mineralogical and Geochemical Characterization of the Kimmeria Intrusion-Related Deposit, Xanthi, NE Greece

NASA Astrophysics Data System (ADS)

Theodoridou, Stella; Melfos, Vasilios; Voudouris, Panagiotis; Miskovic, Aleksandar

2016-04-01

Although intrusion-related systems have not been previously recognized in the European segment of the Tethyan Metallogenic Belt, the Rhodope metallogenic province of SE Balkan peninsula hosts numerous such occurrences. The Kimmeria hydrothermal system incorporates two styles of ore mineralization: i) a massive Au-bearing magnetite-pyrrhotite skarn and ii) a Mo-Cu-Bi-W quartz vein-hosted mineralization, both of which are related to the Oligocene Xanthi pluton (25.5±1.2 to 30±1 My, K-Ar in hornblende and biotite). The Xanthi pluton, consisting of I-type gabbros, monzonites and amphibole-biotite granodiorites, intrudes the basement gneisses, mica schists, amphibolites and marbles of the Southern Rhodope Core Complex; a dome that has gradually exhumed from Paleocene/mid Eocene to Miocene (starting between 65 and >42 to 10 My). The Xanthi pluton emplacement and the magmatically derived hydrothermal fluid circulation were controlled by two major regional structures: the low-angle Kavala-Xanthi-Komotini detachment fault and the Nestos thrust fault. The Kimmeria Au-Cu-Fe skarn mineralization features a well-preserved aureole at the contact between the granodiorite and the surrounding marbles. It consists of two paragenetic stages comprising magnetite and pyrrhotite-rich assemblages. Alteration minerals comprise chlorite and sericite. Bulk chemical analyses of the skarn mineralization revealed relatively high concentration of Cu (1 wt.%), Pb (288 ppm) and Zn (0.74 wt.%). The mineralization is also enriched in As (< 75.8 ppm), W (< 82.1 ppm), Bi (<10.1 ppm), Sb (<331.9 ppm), Ag (< 15.9 ppm), and Sn (< 50 ppm). Te and Au are found in low concentrations of less than 2 ppm and 0.4 ppm, respectively. The Kimmeria Mo-Cu-Bi-W vein-type mineralization comprises a system of cross-cutting and sheeted quartz veins within the granodiorite, with pyrite, chalcopyrite and molybdenite as dominant sulfides. Minor sphalerite, tetrahedrite-tennantite, galena and rutile are also present

Multiple Nonstoichiometric Phases with Discrete Composition Ranges in the CaAu5−CaAu4Bi−BiAu2 System. A Case Study of the Chemistry of Spinodal Decomposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Qisheng; Corbett, John D.

2010-04-01

Synthetic explorations in the CaAu{sub 5}-CaAu{sub 4}Bi-BiAu{sub 2} system at 400 C reveal five separate solid solution regions that show three distinct substitution patterns in the CaAu{sub 5} parent: (I) CaAu{sub 4}(Au{sub 1-m}Bi{sub m}) with 0 {le} m {le} 0.15(1), (II) 0.33(1) {le} m {le} 0.64(1), (III) 0.85(4) {le} m {le} 0.90(2); (IV) (Ca{sub 1-r}Au{sub r})Au{sub 4}(Bi{sub 1-s}Au{sub s}) with 0 {le} r {le} 0.39(1) and 0 {le} s {le} 0.12(2); (V) (Ca{sub 1-p-q}Au{sub p}Bi{sub q})Au{sub 4}Bi with 0.09(2) {le} p {le} 0.13(1) and 0.31(2) {le} q {le} 0.72(4). Single crystal X-ray studies establish that all of these phase regionsmore » have common cubic symmetry F{sub 4}3m and that their structures (MgCu{sub 4}Sn-type, an ordered derivative of MgCu{sub 2}) all feature three-dimensional networks of Au{sub 4} tetrahedra, in which the truncated tetrahedra are centered and capped by Ca/Au, Au/Bi, or Ca/Au/Bi mixtures to give 16-atom Friauf polyhedra. TB-LMTO-ASA and -COHP calculations also reveal that direct interactions between Ca-Au and Ca-Bi pairs of atoms are relatively weak and that the Bi-Au interactions in the unstable ideal CaAu{sub 4}Bi are antibonding in character at E{sub F} but that their bonding is optimized at {+-}1 e. Compositions between the five nonstoichiometric phases appear to undergo spinodal decompositions. The last phenomenon has been confirmed by HRTEM, STEM-HAADF, EPMA, and XRD studies of the nominal composition CaAu{sub 4.25}Bi{sub 0.75}. Its DTA analyses suggest that the phases resulting from spinodal decomposition have nearly the same melting point ({approx}807 C), as expected, and that they are interconvertible through peritectic reactions at {approx}717 C.« less

Extreme enrichment of Se, Te, PGE and Au in Cu sulfide microdroplets: evidence from LA-ICP-MS analysis of sulfides in the Skaergaard Intrusion, east Greenland

NASA Astrophysics Data System (ADS)

Holwell, David A.; Keays, Reid R.; McDonald, Iain; Williams, Megan R.

2015-12-01

The Platinova Reef, in the Skaergaard Intrusion, east Greenland, is an example of a magmatic Cu-PGE-Au sulfide deposit formed in the latter stages of magmatic differentiation. As is characteristic with such deposits, it contains a low volume of sulfide, displays peak metal offsets and is Cu rich but Ni poor. However, even for such deposits, the Platinova Reef contains extremely low volumes of sulfide and the highest Pd and Au tenor sulfides of any magmatic ore deposit. Here, we present the first LA-ICP-MS analyses of sulfide microdroplets from the Platinova Reef, which show that they have the highest Se concentrations (up to 1200 ppm) and lowest S/Se ratios (190-700) of any known magmatic sulfide deposit and have significant Te enrichment. In addition, where sulfide volume increases, there is a change from high Pd-tenor microdroplets trapped in situ to larger, low tenor sulfides. The transition between these two sulfide regimes is marked by sharp peaks in Au, and then Te concentration, followed by a wider peak in Se, which gradually decreases with height. Mineralogical evidence implies that there is no significant post-magmatic hydrothermal S loss and that the metal profiles are essentially a function of magmatic processes. We propose that to generate these extreme precious and semimetal contents, the sulfides must have formed from an anomalously metal-rich package of magma, possibly formed via the dissolution of a previously PGE-enriched sulfide. Other processes such as kinetic diffusion may have also occurred alongside this to produce the ultra-high tenors. The characteristic metal offset pattern observed is largely controlled by partitioning effects, producing offset peaks in the order Pt+Pd>Au>Te>Se>Cu that are entirely consistent with published D values. This study confirms that extreme enrichment in sulfide droplets can occur in closed-system layered intrusions in situ, but this will characteristically form ore deposits that are so low in sulfide that they do

Computational materials design of attractive Fermion system with large negative effective Ueff in the hole-doped Delafossite of CuAlO2, AgAlO2 and AuAlO2: Charge-excitation induced Ueff < 0

NASA Astrophysics Data System (ADS)

Nakanishi, A.; Fukushima, T.; Uede, H.; Katayama-Yoshida, H.

2015-12-01

On the basis of general design rules for negative effective U(Ueff) systems by controlling purely-electronic and attractive Fermion mechanisms, we perform computational materials design (CMD®) for the negative Ueff system in hole-doped two-dimensional (2D) Delafossite CuAlO2, AgAlO2 and AuAlO2 by ab initio calculations with local density approximation (LDA) and self-interaction corrected-LDA (SIC-LDA). It is found that the large negative Ueff in the hole-doped attractive Fermion systems for CuAlO2 (UeffLDA = - 4.53 eV and UeffSIC-LDA = - 4.20 eV), AgAlO2 (UeffLDA = - 4.88 eV and UeffSIC-LDA = - 4.55 eV) and AuAlO2 (UeffLDA = - 4.14 eV and UeffSIC-LDA = - 3.55 eV). These values are 10 times larger than that in hole-doped three-dimensional (3D) CuFeS2 (Ueff = - 0.44 eV). For future calculations of Tc and phase diagram by quantum Monte Carlo simulations, we propose the negative Ueff Hubbard model with the anti-bonding single π-band model for CuAlO2, AgAlO2 and AuAlO2 using the mapped parameters obtained from ab initio electronic structure calculations. Based on the theory of negative Ueff Hubbard model (Noziéres and Schmitt-Rink, 1985), we discuss |Ueff| dependence of superconducting critical temperature (Tc) in the 2D Delafossite of CuAlO2, AgAlO2 and AuAlO2 and 3D Chalcopyrite of CuFeS2, which shows the interesting chemical trend, i.e., Tc increases exponentially (Tc ∝ exp [ - 1 / | Ueff | ]) in the weak coupling regime | Ueff(- 0.44 eV) | < W(∼ 2 eV) (where W is the band width of the negative Ueff Hubbard model) for the hole-doped CuFeS2, and then Tc goes through a maximum when | Ueff(- 4.88 eV , - 4.14 eV) | ∼ W(2.8 eV , 3.5 eV) for the hole-doped AgAlO2 and AuAlO2, and finally Tc decreases with increasing |Ueff| in the strong coupling regime, where | Ueff(- 4.53 eV) | > W(1.7 eV) , for the hole-doped CuAlO2.

Development of Ag-Pd-Au-Cu alloy for multiple dental applications. Part 1. Effects of Pd and Cu contents, and addition of Ga or Sn on physical properties and bond with ultra-low fusing ceramic.

PubMed

Goto, S; Miyagawa, Y; Ogura, H

2000-09-01

Ag-Pd-Au-Cu quaternary alloys consisting of 30-50% Ag, 20-40% Pd, 10-20% Cu and 20% Au (mother alloys) were prepared. Then 5% Sn or 5% Ga was added to the mother alloy compositions, and another two alloy systems (Sn-added alloys and Ga-added alloys) were also prepared. The bond between the prepared alloys and an ultra-low fusing ceramic as well as their physical properties such as the solidus point, liquidus point and the coefficient of thermal expansion were evaluated. The solidus point and liquidus point of the prepared alloys ranged from 802 degrees C to 1142 degrees C and from 931 degrees C to 1223 degrees C, respectively. The coefficient of thermal expansion ranged from 14.6 to 17.1 x 10(-6)/degrees C for the Sn- and Ga-added alloys. In most cases, the Pd and Cu contents significantly influenced the solidus point, liquidus point and coefficient of thermal expansion. All Sn- and Ga-added alloys showed high area fractions of retained ceramic (92.1-100%), while the mother alloy showed relatively low area fractions (82.3%) with a high standard deviation (20.5%). Based on the evaluated properties, six Sn-added alloys and four Ga-added alloys among the prepared alloys were suitable for the application of the tested ultra-low fusing ceramic.

Microstructural, electrical and frequency-dependent properties of Au/p-Cu2ZnSnS4/n-GaN heterojunction.

PubMed

Rajagopal Reddy, V; Janardhanam, V; Won, Jonghan; Choi, Chel-Jong

2017-08-01

An Au/Cu 2 ZnSnS 4 (CZTS)/n-GaN heterojunction (HJ) is fabricated with a CZTS interlayer and probed its chemical states, structural, electrical and frequency-dependent characteristics by XPS, TEM, I-V and C-V measurements. XPS and TEM results confirmed that the CZTS films are formed on the n-GaN surface. The band gap of deposited CZTS film is found to be 1.55eV. The electrical properties of HJ correlated with the Au/n-GaN Schottky junction (SJ). The Au/CZTS/n-GaN HJ reveals a good rectification nature with high barrier height (0.82eV) compared to the Au/n-GaN SJ (0.69eV), which suggests the barrier height is influenced by the CZTS interlayer. The barrier height values assessed by I-V, Cheung's and Norde functions are closely matched with one other, thus the methods used here are reliable and valid. The extracted interface state density (N SS ) of Au/CZTS/n-GaN HJ is lower compared to the Au/n-GaN SJ that suggests the CZTS interlayer plays an important role in the reduction of N SS . Moreover, the capacitance-frequency (C-f) and conductance-frequency (G-f) characteristics of SJ and HJ are measured in the range of 1kHz-1MHz, and found that the capacitance and conductance strappingly dependent on frequency. It is found that the N SS estimated from C-f and G-f characteristics is lower compared to those estimated from I-V characteristics. Analysis confirmed that Poole-Frenkel emission dominates the reverse leakage current in both SJ and HJ, probably related to the structural defects and trap levels in the CZTS interlayer. Copyright © 2017 Elsevier Inc. All rights reserved.

New constraints on the origin of the Skaergaard intrusion Cu-Pd-Au mineralization: Insights from high-resolution X-ray computed tomography

NASA Astrophysics Data System (ADS)

Godel, Bélinda; Rudashevsky, Nikolay S.; Nielsen, Troels F. D.; Barnes, Stephen J.; Rudashevsky, Vladimir N.

2014-03-01

This contribution presents the first detailed three-dimensional (3D) in situ analysis of samples from the Platinova Reef using high-resolution X-ray computed tomography (HRXCT) and 3D image processing and quantification coupled with microscopic and mineralogical investigations. Our HRXCT analyses reveal the complex textural relationships between Cu-rich sulfides (bulk composition close to bornite), skaergaardite (PdCu), Au-rich phases, silicates and Fe-Ti oxides and provide unequivocal textural evidences, not observed previously. The association in 3D between Cu-rich sulfide globules, PdCu alloy and ilmenite is inconsistent with a hydrothermal origin of the Cu-Pd mineralization. In contrast, our results combined with phase diagrams strongly support a primary magmatic origin for the Cu-Pd mineralization where Cu and Pd-rich, Fe-poor sulfide liquid represents a cumulus phase that forms by in-situ nucleation. These sulfide droplets and attached skaergaardite grains were trapped during the formation and crystallization of the Fe-Ti oxides. Subsequent, post-cumulus processes led to the partial to total dissolution of the sulfide not entirely enclosed by the Fe-Ti oxides (i.e., not protected from reaction) leading to the observed variability in Cu and Pd composition at the aggregate (sulfide + PdCu) scale and to the occurrence of free PdCu alloys. In contrast to the PdCu alloy, gold-bearing minerals are never observed entirely enclosed within the Fe-Ti oxide. Two hypotheses can be envisaged for the formation of the gold enriched layer in the upper part of the section. Gold may have either precipitated from high-temperature late magmatic Cl-rich fluids. Alternatively, gold may have been enriched during fractional crystallization after sulfide had been suppressed from the liquidus after the Pd layer crystallized and then deposited along redox barriers.

Role of electron-phonon coupling in finite-temperature dielectric functions of Au, Ag, and Cu

NASA Astrophysics Data System (ADS)

Xu, Meng; Yang, Jia-Yue; Zhang, Shangyu; Liu, Linhua

2017-09-01

Realistic representation of finite temperature dielectric functions of noble metals is crucial in describing the optical properties of advancing applications in plasmonics and optical metamaterials. However, the atomistic origins of the temperature dependence of noble metals' dielectric functions still lack full explanation. In this paper, we implement electronic structure calculations as well as ellipsometry experiments to study the finite temperature dielectric functions of noble metals Au, Ag, and Cu. Theoretically, the intraband dielectric function is described by the Drude model, of which the important quantity electron lifetime is obtained by considering the electron-phonon, electron-electron, and electron-surface scattering mechanism. The electron-phonon coupling is key to determining the temperature dependence of electron lifetime and intraband dielectric function. For the interband dielectric function, it arises from the electronic interband transition. Due to the limitation of incorporating electron-phonon coupling into the interband transition scheme, the temperature dependence of the interband dielectric function is mainly determined by the thermal expansion effect. Experimentally, variable angle spectroscopic ellipsometry measures the dielectric functions of Au and Ag over the temperature range of 300-700 K and spectral range of 2-20 µm. Those experimental measurements are consistent with theoretical results and thus verify the theoretical models for the finite temperature dielectric function.

Age constraints on the hydrothermal history of the Prominent Hill iron oxide copper-gold deposit, South Australia

NASA Astrophysics Data System (ADS)

Bowden, Bryan; Fraser, Geoff; Davidson, Garry J.; Meffre, Sebastien; Skirrow, Roger; Bull, Stuart; Thompson, Jay

2017-08-01

The Mesoproterozoic Prominent Hill iron-oxide copper-gold deposit lies on the fault-bound southern edge of the Mt Woods Domain, Gawler Craton, South Australia. Chalcocite-bornite-chalcopyrite ores occur in a hematitic breccia complex that has similarities to the Olympic Dam deposit, but were emplaced in a shallow water clastic-carbonate package overlying a thick andesite-dacite pile. The sequence has been overturned against the major, steep, east-west, Hangingwall Fault, beyond which lies the clastic to potentially evaporitic Blue Duck Metasediments. Immediately north of the deposit, these metasediments have been intruded by dacite porphyry and granitoid and metasomatised to form magnetite-calc-silicate skarn ± pyrite-chalcopyrite. The hematitic breccia complex is strongly sericitised and silicified, has a large sericite ± chlorite halo, and was intruded by dykes during and after sericitisation. This paper evaluates the age of sericite formation in the mineralised breccias and provides constraints on the timing of granitoid intrusion and skarn formation in the terrain adjoining the mineralisation. The breccia complex contains fragments of granitoid and porphyry that are found here to be part of the Gawler Range Volcanics/Hiltaba Suite magmatic event at 1600-1570 Ma. This indicates that some breccia formation post-dated granitoid intrusion. Monazite and apatite in Fe-P-REE-albite metasomatised granitoid, paragenetically linked with magnetite skarn formation north of the Hangingwall Fault, grew soon after granitoid intrusion, although the apatite experienced U-Pb-LREE loss during later fluid-mineral interaction; this accounts for its calculated age of 1544 ± 39 Ma. To the south of the fault, within the breccia, 40Ar-39Ar ages yield a minimum age of sericitisation (+Cu+Fe+REE) of dykes and volcanics of ˜1575 Ma, firmly placing Prominent Hill ore formation as part of the Gawler Range Volcanics/Hiltaba Suite magmatic event within the Olympic Cu-Au province of the

Pentatwinned Cu Nanowires with Ultrathin Diameters below 20 nm and Their Use as Templates for the Synthesis of Au-Based Nanotubes

DOE PAGES

Luo, Ming; Zhou, Ming; Rosa da Silva, Robson; ...

2017-01-24

Here, we report a one-pot method for the facile synthesis of Cu nanowires in high purity, together with ultrathin diameters well below 20 nm. Selected area electron diffraction and high-resolution transmission electron microscopy studies confirm that the Cu nanowires are grown along the <110> direction to give pentatwinned, one-dimensional nanostructures, enclosed by five {100} facets on the side surface. A systematic study further indicates that it is critical to conduct the synthesis under an argon atmosphere in order to improve the purity and uniformity of the nanowires while keeping their diameters thinner than 20 nm. Finally, we demonstrate the usemore » of these nanowires as sacrificial templates for the synthesis of Au-based nanotubes through a galvanic replacement process.« less

Pentatwinned Cu Nanowires with Ultrathin Diameters below 20 nm and Their Use as Templates for the Synthesis of Au-Based Nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Ming; Zhou, Ming; Rosa da Silva, Robson

Here, we report a one-pot method for the facile synthesis of Cu nanowires in high purity, together with ultrathin diameters well below 20 nm. Selected area electron diffraction and high-resolution transmission electron microscopy studies confirm that the Cu nanowires are grown along the <110> direction to give pentatwinned, one-dimensional nanostructures, enclosed by five {100} facets on the side surface. A systematic study further indicates that it is critical to conduct the synthesis under an argon atmosphere in order to improve the purity and uniformity of the nanowires while keeping their diameters thinner than 20 nm. Finally, we demonstrate the usemore » of these nanowires as sacrificial templates for the synthesis of Au-based nanotubes through a galvanic replacement process.« less

Using the concentration-volume (C-V) fractal model in the delineation of gold mineralized zones within the Tepeoba porphyry Cu-Mo-Au, Balikesir, NW Turkey

NASA Astrophysics Data System (ADS)

Kumral, Mustafa; Abdelnasser, Amr; Karaman, Muhittin; Budakoglu, Murat

2016-04-01

The Tepeoba porphyry Cu-Mo-Au mineralization that located at the Biga peninsula (W Turkey) developed around the Eybek pluton concentrated at its southern contact. This mineralization that hosted in the hornfels rocks of Karakaya Complex is associated with three main alteration zones; potassic, phyllic and propylitic alterations along the fault controlled margins of the Eybek pluton and quartz stockwork veining as well as brecciation zones. As well as two mineralized zones were occurred in the mine area; hypogene and oxidation/supergene zone. The hypogene zone has differentiated alteration types; high potassic and low phyllic alteration, while the oxidation/supergene zone has high phyllic and propylitic alterations. This work deals with the delineation of gold mineralized zone within this porphyry deposit using the concentration-volume (C-V) fractal model. Five zones of gold were calculated using its power-law C-V relationship that revealed that the main phase of gold mineralization stated at 5.3083 ppm Au concentration. In addition, the C-V log-log plot shows that the highly and moderately Au mineralization zone developed in western part of deposit correlated with oxidation zone related to propylitic alteration. On the other hand, its weakly mineralization zone has a widespread in the hypogene zone related to potassic alteration. This refers to the enrichment of gold and depletion of copper at the oxidation/supergene zone is due to the oxidation/supergene alteration processes that enrich the deposits by the meteoric water. Keywords: Concentration-volume (C-V) fractal model; gold mineralized zone; Tepeoba porphyry Cu-Mo-Au; Balikesir; NW Turkey.

Retrieval of Au, Ag, Cu precious metals coupled with electric energy production via an unconventional coupled redox fuel cell reactor.

PubMed

Zhang, Hui-Min; Fan, Zheng; Xu, Wei; Feng, Xiao; Wu, Zu-Cheng

2017-09-15

The recovery of heavy metals from aqueous solutions or e-wastes is of upmost importance. Retrieval of Au, Ag, and Cu with electricity generation through building an ethanol-metal coupled redox fuel cells (CRFCs) is demonstrated. The cell was uniquely assembled on PdNi/C anode the electro-oxidation of ethanol takes place to give electrons and then go through the external circuit reducing metal ions to metallic on the cathode, metals are recovered. Taking an example of removal of 100mgL -1 gold in 0.5M HAc-NaAc buffer solution as the catholyte, 2.0M ethanol in 1.0M alkaline solution as the anolyte, an open circuit voltage of 1.4V, more than 96% of gold removal efficiency in 20h, and equivalent energy production of 2.0kWhkg -1 of gold can be readily achieved in this system. When gold and copper ions coexist, it was confirmed that metallic Cu is formed on the cathodic electrode later than metallic Au formation by XPS analysis. Thus, this system can achieve step by step electrodeposition of gold and copper while the two metal ions coexisting. This work develops a new approach to retrieve valuable metals from aqueous solution or e-wastes. Copyright © 2017 Elsevier B.V. All rights reserved.

AmeriFlux MX-Lpa La Paz

DOE Data Explorer

Oechel, Walter [San Diego State University

2016-01-01

This is the AmeriFlux version of the carbon flux data for the site MX-Lpa La Paz. Site Description - As evident by some very large Cardon (5-7 meters), according to Coyle and Roberts, 1975, extent vegetation has likely been around at least 200 years. Until about 15 years ago from 1996, site was used for livestock production and selective firewood extraction. However, when I look over the fence where there has been livestock activity, not much difference

Site preference of ternary alloying additions to NiTi: Fe, Pt, Pd, Au, Al, Cu, Zr and Hf

NASA Technical Reports Server (NTRS)

Bozzolo, Guillermo; Noebe, Ronald D.; Mosca, Hugo O.

2004-01-01

Atomistic modeling of the site substitution behavior of Pd in NiTi (J. Alloys and Comp. (2004), in press) has been extended to examine the behavior of several other alloying additions, namely, Fe, Pt, Au, Al, Cu, Zr and Hf in this important shape memory alloy. It was found that all elements, to a varying degree, displayed absolute preference for available sites in the deficient sublattice. How- ever, the energetics of the different substitutional schemes, coupled with large scale simulations indicate that the general trend in all cases is for the ternary addition to want to form stronger ordered structures with Ti.

Concealed basalt-matrix diatremes with Cu-Au-Ag-(Mo)-mineralized xenoliths, Santa Cruz Porphyry Cu-(Mo) System, Pinal County, Arizona

USGS Publications Warehouse

Vikre, Peter; Graybeal, Frederick T.; Koutz, Fleetwood R.

2014-01-01

The Santa Cruz porphyry Cu-(Mo) system near Casa Grande, Arizona, includes the Sacaton mine deposits and at least five other concealed, mineralized fault blocks with an estimated minimum resource of 1.5 Gt @ 0.6% Cu. The Late Cretaceous-Paleocene system has been dismembered and rotated by Tertiary extension, partially eroded, and covered by Tertiary-Quaternary basin-fill deposits. The mine and mineralized fault blocks, which form an 11 km (~7 miles) by 1.6 km (~1 mile) NE-SW–trending alignment, represent either pieces of one large deposit, several deposits, or pieces of several deposits. The southwestern part of the known system is penetrated by three or more diatremes that consist of heterolithic breccia pipes with basalt and clastic matrices, and subannular tuff ring and maar-fill sedimentary deposits associated with vents. The tephra and maar-fill deposits, which are covered by ~485 to 910 m (~1,600–3,000 ft) of basin fill, lie on a mid-Tertiary erosion surface of Middle Proterozoic granite and Late Cretaceous porphyry, which compose most xenoliths in pipes and are the host rocks of the system. Some igneous xenoliths in the pipes contain bornite-chalcopyrite-covellite assemblages with hypogene grades >1 wt % Cu, 0.01 ounces per ton (oz/t) Au, 0.5 oz/t Ag, and small amounts of Mo (<0.01 wt %). These xenoliths were derived from mineralized rocks that have not been encountered in drill holes, and attest to additional, possibly higher-grade deposits within or subjacent to the known system.The geometry, stratigraphy, and temporal relationships of pipes and tephras, interpreted from drill hole spacing and intercepts, multigenerational breccias and matrices, reequilibrated and partially decomposed sulfide-oxide mineral assemblages, melted xenoliths, and breccia matrix compositions show that the diatremes formed in repeated stages. Initial pulses of basalt magma fractured granite, porphyry, and other crustal rocks during intrusion, transported multi-sized fragments

CuO-induced signal amplification strategy for multiplexed photoelectrochemical immunosensing using CdS sensitized ZnO nanotubes arrays as photoactive material and AuPd alloy nanoparticles as electron sink.

PubMed

Sun, Guoqiang; Zhang, Yan; Kong, Qingkun; Zheng, Xiaoxiao; Yu, Jinghua; Song, Xianrang

2015-04-15

In this work, multiplexed photoelectrochemical (PEC) immunoassays are introduced into an indium tin oxide (ITO) device. Firstly, the ITO device is fabricated using a simple acid etch treatment method. Secondly, AuPd alloy nanoparticles are electro-deposited on ITO working electrodes as electron sink to construct the immunosensor platform. After that, ZnO nanotubes (ZNTs) arrays are synthesized via chemical etching of ZnO nanorods that are grown on AuPd surface by electrochemical deposition method. Subsequently, CdS is electro-deposited on ZNTs arrays and used as photoactive material. Then, CuO nanoseeds are labeled with signal antibodies and firstly used as PEC signal amplification label. The introduction of CuO brings signal amplification because of the conduction band (CB) of both CuO and ZnO are lower than that of CdS, CuO will compete the photo-induced electrons in CB of CdS with ZnO, leading to the decrease of the photocurrent intensity. Using cancer antigen 125, prostate specific antigen and α-fetoprotein as model analytes, the proposed immunoassay exhibits excellent precision and sensitivity. Meanwhile, this work provides a promising, addressable and simple strategy for the multi-detection of tumor markers. Copyright © 2014 Elsevier B.V. All rights reserved.

Contributions of 3'-overhang to the dissociation of small interfering RNAs from the PAZ domain: molecular dynamics simulation study.

PubMed

Lee, Hui Sun; Lee, Soo Nam; Joo, Chul Hyun; Lee, Heuiran; Lee, Han Saem; Yoon, Seung Yong; Kim, Yoo Kyum; Choe, Han

2007-03-01

RNA interference (RNAi) is a 'knock-down' reaction to reduce expression of a specific gene through highly regulated, enzyme-mediated processes. Small interfering RNAs (siRNAs) are RNA molecules that play an effector role in RNAi and can bind the PAZ domains present in Dicer and RISC. We investigated the interaction between the PAZ domain and the siRNA-like duplexes through dissociation molecular dynamics (DMD) simulations. Specifically, we focused on the response of the PAZ domain to various 3'-overhang structures of the siRNA-like duplexes. We found that the siRNA-like duplex with the 3' UU-overhang made relatively more stable complex with the PAZ domain compared to those with 3' CC-, AA-, and GG-overhangs. The siRNA-like duplex with UU-overhang was easily dissociated from the PAZ domain once the structural stability of the complex is impaired. Interestingly, the 3' UU-overhang spent the least time at the periphery region of the binding pocket during the dissociation process, which can be mainly attributable to UU-overhang's smallest number of hydrogen bonds.

Quantification of elemental area densities in multiple metal layers (Au/Ni/Cu) on a Cr-coated quartz glass substrate for certification of NMIJ CRM 5208-a.

PubMed

Ariga, Tomoko; Zhu, Yanbei; Ito, Mika; Takatsuka, Toshiko; Terauchi, Shinya; Kurokawa, Akira; Inagaki, Kazumi

2018-04-01

Area densities of Au/Ni/Cu layers on a Cr-coated quartz substrate were characterized to certify a multiple-metal-layer certified reference material (NMIJ CRM5208-a) that is intended for use in the analysis of the layer area density and the thickness by an X-ray fluorescence spectrometer. The area densities of Au/Ni/Cu layers were calculated from layer mass amounts and area. The layer mass amounts were determined by using wet chemical analyses, namely inductively coupled plasma mass spectrometry (ICP-MS), isotope-dilution (ID-) ICP-MS, and inductively coupled plasma optical emission spectrometry (ICP-OES) after dissolving the layers with diluted mixture of HCl and HNO 3 (1:1, v/v). Analytical results of the layer mass amounts obtained by the methods agreed well with each another within their uncertainty ranges. The area of the layer was determined by using a high-resolution optical scanner calibrated by Japan Calibration Service System (JCSS) standard scales. The property values of area density were 1.84 ± 0.05 μg/mm 2 for Au, 8.69 ± 0.17 μg/mm 2 for Ni, and 8.80 ± 0.14 μg/mm 2 for Cu (mean ± expanded uncertainty, coverage factor k = 2). In order to assess the reliability of these values, the density of each metal layer calculated from the property values of the area density and layer thickness measured by using a scanning electron microscope were compared with available literature values and good agreement between the observed values and values obtained in previous studies.

X-ray and neutron diffraction anomalies preceding martensitic phase transformation in AuCuZn2 alloys

NASA Astrophysics Data System (ADS)

Nagasawa, A.; Makita, T.; Nakanishi, N.; Iizumi, M.; Morii, Y.

1988-04-01

The present paper gives the results obtained by the X-ray and neutron diffraction studies on the single crystals of the beta-1 AuCuZn2 alloys. As precursor phenomena, the dispersion relation of the [110] TA1 phonon exhibits significant dip near 2/3 [110] q max position and anomalous peaks appear around 1/3 and 2/3 [110] q max positions. Characteristics of the interplanar force constants, obtained by the analysis of the dispersion relation, and the positions of the anomalous peaks predict the martensite structures to be formed in the beta phase alloys. In the present case, both the 6R and 18R martensites will be formed by cooling and/or under the stress field.

Microthermometry of enargite-hosted fluid inclusions from the Lepanto, Philippines, high-sulfidation Cu sbnd Au deposit

NASA Astrophysics Data System (ADS)

Mancano, D. P.; Campbell, A. R.

1995-10-01

The spatial relation between porphyry and high-sulfidation epithermal deposits is particularly well revealed in the Mankayan mineral district of northern Luzon, Philippines, where the Lepanto high-sulfidation Cu sbnd Au deposit lies over and adjacent to the Far Southeast (FSE) porphyry Cu sbnd Au deposit. Consequently, a study was undertaken to characterize the fluids responsible for epithermal mineralization in this environment. The ore stage at Lepanto consists of enargite-luzonite (Cu 3AsS 4), pyrite, tennantite-tetrahedrite, and chalcopyrite. Infrared petrography of the enargite reveals variable transparency, with growth banding and twinning visible in euhedral specimens. Two phase (liquid > vapor) fluid inclusions occur as primary and secondary types ranging from <1 to 80 micrometers in length, with tabular, cylindrical, or oval shapes. Homogenization temperatures ( Th) of fluid inclusions in enargite were measured from within the lateral (3.0 km) and vertical (0.5 km) extent of the enargite mineralization. These values show a cooling trend toward the northwest, away from the area over the porphyry deposit, with average Th ranging from 285°C (proximal) to 166°C (distal). Ice melting temperatures ( Tm) were measured using a cycling technique, as ice was usually not visible in frozen inclusions. Apparent salinities range from 4.5 to 0.2 eq. wt% NaCl, with samples from the margins of the deposit showing a general decrease in apparent salinity with lower Th. Secondary fluid inclusions in quartz phenocrysts tend to have a higher average Th and lower apparent salinities compared to enargite-hosted inclusion fluids from the same locations. Several samples of pyrite are also transparent to IR radiation, and show internal features such as growth banding, and in one instance a two phase (liquid > vapor) fluid inclusion. This inclusion yielded a salinity of 1.2 eq. wt% NaCl. There is a large discrepancy in Th and apparent salinities between the enargite mineralization

Molybdenite Re/Os dating, zircon U-Pb age and geochemistry of granitoids in the Yangchuling porphyry W-Mo deposit (Jiangnan tungsten ore belt), China: Implications for petrogenesis, mineralization and geodynamic setting

NASA Astrophysics Data System (ADS)

Mao, Jingwen; Xiong, Bikang; Liu, Jun; Pirajno, Franco; Cheng, Yanbo; Ye, Huishou; Song, Shiwei; Dai, Pan

2017-08-01

The Yangchuling W-Mo deposit, located in the Jiangnan porphyry-skarn (JNB) tungsten ore belt, is the first recognized typical porphyry W-Mo deposit in China in the 1980's. Stockworks and disseminated W-Mo mineralization occur in the roof pendant of a 0.3 km2 monzogranitic porphyry stock that intruded into a granodiorite stock, hosted by Neoproterozoic phyllite and slate. LA-ICPMS zircon U-Pb analyses suggest that of the monzogranitic porphyry and granodiorite were formed at 143.8 ± 0.5 Ma and 149.8 ± 0.6 Ma, respectively. Six molybdenite samples yielded a Re-Os weighted mean age of 146.4 ± 1.0 Ma. Geochemical data show that both granodiorite and monzogranitic porphyry are characterized by enrichment of large ion lithophile elements (LILE) relative to high field strength elements (HFSE), indicating a peraluminous nature (A/CNK = 1.01-1.08). Two granitoids are characterized by a negative slope with significant light REE/heavy REE fractionation [(La/Yb)N = 8.38-23.20] and negative Eu anomalies (Eu/Eu* = 0.69-0.76). The P2O5 contents of the Yangchuling granitoids range from 0.12% to 0.17% and exhibit a negative correlation with SiO2, reflecting that they are highly fractionated I-type. They have high initial 87Sr/86Sr ratios (0.7104-0.7116), low negative εNd(t) (- 5.05 to - 5.67), and homogeneous εHf(t) between - 1.39 and - 2.17, indicating similar sources. Additionally, two-stage Nd model ages (TDM2) of 1.3-1.4 Ga and two-stage Hf model ages (TDM2) of 1.2-1.3 Ga are consistent, indicating that Neoproterozoic crustal rocks of the Shuangqiaoshan Group could have contributed to form the Yangchuling magmas. Considering the two groups of parallel Late Mesozoic ore belts, namely the Jiangnan porphyry-skarn tungsten belt (JNB) in the south and the Middle-Lower Yangtze River porphyry-skarn Cu-Au-Mo-Fe ore belt (YRB) in the north, the Nanling granite-related W-Sn ore belt (NLB) in the south, the neighboring Qin-Hang porphyry-skarn Cu-Mo-hydrothermal Pb-Zn-Ag ore belt (QHB

Charge-Dependent Directed Flow in Cu + Au Collisions at s N N = 200 GeV

DOE PAGES

Adamczyk, L.; Adkins, J. K.; Agakishiev, G.; ...

2017-01-05

Here we present the first measurement of charge-dependent directed flow in Cu + Au collisions atmore » $$\\sqrt{s}$$$_ {NN}$$ = 200 GeV . The results are presented as a function of the particle transverse momentum and pseudorapidity for different centralities. A finite difference between the directed flow of positive and negative charged particles is observed that qualitatively agrees with the expectations from the effects of the initial strong electric field between two colliding ions with different nuclear charges. The measured difference in directed flow is much smaller than that obtained from the parton-hadron-string-dynamics model, which suggests that most of the electric charges, i.e., quarks and antiquarks, have not yet been created during the lifetime of the strong electric field, which is of the order of, or less than, 1fm / c .« less

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

Mineralogical and geochemical characterization of waste rocks from a gold mine in northeastern Thailand: application for environmental impact protection.

PubMed

Assawincharoenkij, Thitiphan; Hauzenberger, Christoph; Ettinger, Karl; Sutthirat, Chakkaphan

2018-02-01

Waste rocks from gold mining in northeastern Thailand are classified as sandstone, siltstone, gossan, skarn, skarn-sulfide, massive sulfide, diorite, and limestone/marble. Among these rocks, skarn-sulfide and massive sulfide rocks have the potential to generate acid mine drainage (AMD) because they contain significant amounts of sulfide minerals, i.e., pyrrhotite, pyrite, arsenopyrite, and chalcopyrite. Moreover, both sulfide rocks present high contents of As and Cu, which are caused by the occurrence of arsenopyrite and chalcopyrite, respectively. Another main concern is gossan contents, which are composed of goethite, hydrous ferric oxide (HFO), quartz, gypsum, and oxidized pyroxene. X-ray maps using electron probe micro-analysis (EPMA) indicate distribution of some toxic elements in Fe-oxyhydroxide minerals in the gossan waste rock. Arsenic (up to 1.37 wt.%) and copper (up to 0.60 wt.%) are found in goethite, HFO, and along the oxidized rim of pyroxene. Therefore, the gossan rock appears to be a source of As, Cu, and Mn. As a result, massive sulfide, skarn-sulfide, and gossan have the potential to cause environmental impacts, particularly AMD and toxic element contamination. Consequently, the massive sulfide and skarn-sulfide waste rocks should be protected from oxygen and water to avoid an oxidizing environment, whereas the gossan waste rocks should be protected from the formation of AMD to prevent heavy metal contamination.

Sulfur Isotopic Composition of Sulfides in Skarn and Vein Mineralization of the Dal'negorsk Ore Region (Primorye)

NASA Astrophysics Data System (ADS)

Rogulina, L. I.; Moiseenko, V. G.; Odarichenko, E. G.; Voropayeva, E. N.

2018-03-01

The S isotopic composition in the ore-forming minerals galena and sphalerite was studied in different Ag-Pb-Zn deposits of the region. It was pointed out that the δ34S modal values range from-1.2 to +6.7‰ in the minerals with a positive value for the skarn mineralization. In the flyschoid formation, the vein-type mineralization is characterized by negative and positive values. The narrow range of δ34S values indicates the marginal-continental type of the mineralization and the multiple origins of its sources.

Charge-Dependent Directed Flow in Cu +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.; Anderson, D. M.; Aoyama, R.; Aparin, A.; Arkhipkin, D.; Aschenauer, E. C.; Ashraf, M. U.; 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, 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.; Esumi, S.; Evdokimov, O.; Eyser, O.; Fatemi, R.; Fazio, S.; Federic, P.; Fedorisin, J.; Feng, Z.; Filip, P.; Finch, E.; 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, B.; Huang, X.; Huang, H. Z.; Huang, T.; Huck, P.; Humanic, T. J.; Igo, G.; Jacobs, W. W.; Jentsch, A.; Jia, J.; Jiang, K.; Jowzaee, S.; 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, Y.; Li, C.; Li, W.; Li, X.; Li, X.; Lin, T.; Lisa, M. A.; Liu, Y.; Liu, F.; Ljubicic, T.; Llope, W. J.; Lomnitz, M.; Longacre, R. S.; Luo, X.; Luo, S.; Ma, G. L.; Ma, R.; 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.; Miller, Z. W.; 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.; Nonaka, T.; 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.; Przybycien, M.; Putschke, J.; Qiu, H.; Quintero, A.; Ramachandran, S.; Ray, R. L.; Reed, R.; Rehbein, M. J.; Ritter, H. G.; Roberts, J. B.; Rogachevskiy, O. V.; Romero, J. L.; Roth, J. D.; 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, M. K.; Sharma, B.; Shen, W. Q.; Shi, S. S.; Shi, Z.; Shou, Q. Y.; Sichtermann, E. P.; Sikora, R.; Simko, M.; Singha, S.; Skoby, M. J.; Smirnov, D.; Smirnov, N.; Solyst, W.; Song, L.; Sorensen, P.; Spinka, H. M.; Srivastava, B.; Stanislaus, T. D. S.; Stepanov, M.; Stock, R.; Strikhanov, M.; Stringfellow, B.; Sugiura, T.; Sumbera, M.; Summa, B.; Sun, Z.; Sun, Y.; Sun, X. M.; Surrow, B.; Svirida, D. N.; Tang, A. H.; Tang, Z.; 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.; Varma, R.; Vasiliev, A. N.; Vertesi, R.; Videbæk, F.; Vokal, S.; Voloshin, S. A.; Vossen, A.; Wang, G.; Wang, F.; Wang, J. S.; Wang, Y.; Wang, H.; Wang, Y.; Webb, J. C.; Webb, G.; Wen, L.; Westfall, G. D.; Wieman, H.; Wissink, S. W.; Witt, R.; Wu, Y.; Xiao, Z. G.; Xie, W.; Xie, G.; Xin, K.; Xu, Q. H.; Xu, Y. F.; Xu, H.; Xu, Z.; Xu, N.; Xu, J.; Yang, C.; Yang, Y.; Yang, S.; Yang, Y.; Yang, Q.; Yang, Y.; Ye, Z.; Ye, Z.; Yi, L.; Yip, K.; Yoo, I.-K.; Yu, N.; Zbroszczyk, H.; Zha, W.; Zhang, J.; Zhang, X. P.; Zhang, S.; Zhang, Y.; Zhang, J. B.; Zhang, Z.; Zhang, S.; Zhang, J.; Zhao, J.; Zhong, C.; Zhou, L.; Zhu, X.; Zoulkarneeva, Y.; Zyzak, M.; STAR Collaboration

2017-01-01

We present the first measurement of charge-dependent directed flow in Cu +Au collisions at √{sN N }=200 GeV . The results are presented as a function of the particle transverse momentum and pseudorapidity for different centralities. A finite difference between the directed flow of positive and negative charged particles is observed that qualitatively agrees with the expectations from the effects of the initial strong electric field between two colliding ions with different nuclear charges. The measured difference in directed flow is much smaller than that obtained from the parton-hadron-string-dynamics model, which suggests that most of the electric charges, i.e., quarks and antiquarks, have not yet been created during the lifetime of the strong electric field, which is of the order of, or less than, 1 fm /c .

Order-disorder effects on the elastic properties of CuMPt6 (M=Cr and Co) compounds

NASA Astrophysics Data System (ADS)

Huang, Shuo; Li, Rui-Zi; Qi, San-Tao; Chen, Bao; Shen, Jiang

2014-04-01

The elastic properties of CuMPt6 (M=Cr and Co) in disordered face-centered cubic (fcc) structure and ordered Cu3Au-type structure are studied with lattice inversion embedded-atom method. The calculated lattice constant and Debye temperature agree quite well with the comparable experimental data. The obtained formation enthalpy demonstrates that the Cu3Au-type structure is energetically more favorable. Numerical estimates of the elastic constants, bulk/shear modulus, Young's modulus, Poisson's ratio, elastic anisotropy, and Debye temperature for both compounds are performed, and the results suggest that the disordered fcc structure is much softer than the ordered Cu3Au-type structure.

Aluminum and gold deposition on cleaved single crystals of Bi2CaSr2Cu2O8 superconductor

NASA Astrophysics Data System (ADS)

Wells, B. O.; Lindberg, P. A. P.; Shen, Z.-X.; Dessau, D. S.; Lindau, I.; Spicer, W. E.; Mitzi, D. B.; Kapitulnik, A.

1989-02-01

We have used photoelectron spectroscopy to study the changes in the electronic structure of cleaved, single crystal Bi2CaSr2Cu2O8 caused by deposition of aluminum and gold. Al reacts strongly with the superconductor surface. Even the lowest coverages of Al reduces the valency of Cu in the superconductor, draws oxygen out of the bulk, and strongly modifies the electronic states in the valence band. The Au shows little reaction with the superconductor surface. Underneath Au, the Cu valency is unchanged and the core peaks show no chemically shifted components. Au appears to passivate the surface of the superconductor and thus may aid in the processing of the Bi-Ca-Sr-Cu-O material. These results are consistent with earlier studies of Al and Au interfaces with other, polycrystalline oxide superconductors. Comparing with our own previous results, we conclude that Au is superior to Ag in passivating the Bi-Ca-Sr-Cu-O surface.

Effects of He implantation on radiation induced segregation in Cu-Au and Ni-Si alloys

NASA Astrophysics Data System (ADS)

Iwase, A.; Rehn, L. E.; Baldo, P. M.; Funk, L.

Effects of He implantation on radiation induced segregation (RIS) in Cu-Au and Ni-Si alloys were investigated using in situ Rutherford backscattering spectrometry during simultaneous irradiation with 1.5-MeV He and low-energy (100 or 400-keV) He ions at elevated temperatures. RIS during single He ion irradiation, and the effects of pre-implantation with low-energy He ions, were also studied. RIS near the specimen surface, which was pronounced during 1.5-MeV He single-ion irradiation, was strongly reduced under low-energy He single-ion irradiation, and during simultaneous irradiation with 1.5-MeV He and low-energy He ions. A similar RIS reduction was also observed in the specimens pre-implanted with low-energy He ions. The experimental results indicate that the accumulated He atoms cause the formation of small bubbles, which provide additional recombination sites for freely migrating defects.

The effect of copper and silver on the properties of Au-ZnO catalyst and its activity in glycerol oxidation

NASA Astrophysics Data System (ADS)

Kaskow, Iveta; Decyk, Piotr; Sobczak, Izabela

2018-06-01

The goal of this work was to use ZnO as a support for gold and copper (Au-Cu system) or gold and silver (Au-Ag system) and comparison of the effect of copper and silver on the properties of gold and its activity in glycerol oxidation with oxygen in the liquid phase. The samples prepared were fully characterized by XRD, TEM techniques and UV-vis, XPS, ESR spectroscopic methods. It was found that the introduction of copper and silver changed the electronic state of gold loaded on ZnO by the electron transfer between metals. Three different metallic gold species were identified in calcined catalysts: (Au°)δ- (Au-ZnO), (Au°)η- (AuCu-ZnO) and (Au°)γ- (AuAg-ZnO), where δ-,η-,γ- indicate a different partial negative charge on metallic gold and γ > δ > η. The results showed that (Au°)η- centers (metallic gold with the lowest negative charge) formed on AuCu-ZnO were the most active in glycerol oxidation. The increase in the negative charge on metallic gold loaded on AuAg-ZnO reduced the gold activity in silver containing sample. The glyceric acid adsorption and desorption rate influenced the selectivity of the catalysts.

Origin of the world-class PGE-Au mineralisation in the Skaergaard intrusion by bulk S-saturation, accumulation, partial dissolution, and secondary reef formation.

NASA Astrophysics Data System (ADS)

Daugaard Nielsen, Troels Frederik

2013-04-01

The Skaergaard intrusion is the type locality for stratiform "Skaergaard-type" PGE-Au mineralisations with layers rich in PGE, followed by Au and Cu. Models for stratiform PGE mineralisations divide into uppers and downers models. Downers models assume bulk liquid S-saturation followed by a variety of accumulation processes and the second model the scavenging of metals by fluids deep in intrusions and deposition in chemical traps above. This investigation is based on continuous profiling in roof, walls and floor. Cu anomalies in roof, walls and floor are contemporaneous and systematics in Pd/Pt and Pd/Au ratios document bulk liquid S-saturation, no loss of precious metal below the mineralisation and no obvious chemical traps. A classic downers process is documented. The timing of the mineralisation is controlled by composition of liquidus plagioclase and fraction of residual magma (F). PGE concentrations are an order of magnitude higher in the floor mineralisation due to accumulation. Systematics across the mineralisation shows in the centre of the intrusion 5 main levels of Pd-concentration followed by an Au and a Cu-level. All levels PGE and Au levels have c. 100 ppm Cu and show no correlation to PGE and Au. 90% of all PGE is contained in one phase, skaergaardite (PdCu).The lower and main PGE concentration has moderate Pd/Pt ratios. Overlying secondary reefs have high, basal Pd/Pt and show local S-saturation reflecting d-values of PGE between sulphide and silicate liquid. No basal high Pd/Pt anomaly occurs at Au and Cu levels and the floor shows four types of mineralisation. The main PGE reef (Pd5) has gradual increase and decrease in PGE and Pd/Pt, dissolution of sulphide, increasing PGE+Au/Cu due to reaction between interstial and documented reactive Fe-rich silicate melt and the bulk magma sulfides. Dissolution of Cu-sulfide increases PGE/Cu, reduces the size of droplets to 30µ (av.) and provides metals for secondary reefs above - formed by migration of

Dynamics of copper-phthalocyanine molecules on Au/Ge(001).

PubMed

Sotthewes, K; Heimbuch, R; Zandvliet, H J W

2015-10-07

Spatially resolved current-time scanning tunneling spectroscopy combined with current-distance spectroscopy has been used to characterize the dynamic behavior of copper-phthalocyanine (CuPc) molecules adsorbed on a Au-modified Ge(001) surface. The analyzed CuPc molecules are adsorbed in a "molecular bridge" configuration, where two benzopyrrole groups (lobes) are connected to a Au-induced nanowire, whereas the other two lobes are connected to the adjacent nanowire. Three types of lobe configurations are found: a bright lobe, a dim lobe, and a fuzzy lobe. The dim and fuzzy lobes exhibit a well-defined switching behavior between two discrete levels, while the bright lobe shows a broad oscillation band. The observed dynamic behavior is induced by electrons that are injected into the LUMO+1 orbital of the CuPc molecule. By precisely adjusting the tip-molecule distance, the switching frequency of the lobes can be tuned accurately.

Theoretical investigation of thermoelectric and elastic properties of intermetallic compounds ScTM (TM = Cu, Ag, Au and Pd)

NASA Astrophysics Data System (ADS)

Iqbal, R.; Bilal, M.; Jalali-Asadabadi, S.; Rahnamaye Aliabad, H. A.; Ahmad, Iftikhar

2018-01-01

In this paper, we explore the structural, electronic, thermoelectric and elastic properties of intermetallic compounds ScTM (TM = Cu, Ag, Au and Pd) using density functional theory. The produced results show high values of Seebeck coefficients and electrical conductivity for these materials. High power factor for these materials at room-temperature shows that these materials may be beneficial for low-temperature thermoelectric devices and alternative energy sources. Furthermore, elastic properties of these compounds are also calculated, which are used to evaluate their mechanical properties. The Cauchy’s pressure and B/G ratio figure out that these compounds are ductile in nature. The calculated results also predict that these compounds are stable against deforming force.

Magnetic Anisotropy and Chemical Order of Artificially Synthesized L10-Ordered FeNi Films on Au-Cu-Ni Buffer Layers

NASA Astrophysics Data System (ADS)

Kojima, Takayuki; Mizuguchi, Masaki; Koganezawa, Tomoyuki; Osaka, Keiichi; Kotsugi, Masato; Takanashi, Koki

2012-01-01

L10-FeNi films were grown by alternate monatomic layer deposition on Au-Cu-Ni buffer layers at several substrate temperatures (Ts), and the relation between the uniaxial magnetic anisotropy energy (Ku) and the long-range chemical order parameter (S) was investigated. A large Ku of (7.0 ±0.2) ×106 erg/cm3 and S of 0.48 ±0.05 were obtained. The value of Ku was larger than those reported previously for artificially synthesized FeNi films. It was first found that both Ku and S increased with Ts, and Ku was roughly proportional to S.

Nuclear Matter Effects on ϕ Production in Cu+Au Collisions at √{s}NN = 200 GeV with the PHENIX Muon Arms at RHIC

NASA Astrophysics Data System (ADS)

Jezghani, Margaret; Phenix Collaboration

2015-10-01

A major objective in the field of high-energy nuclear physics is to quantify and characterize the quark-gluon plasma formed in relativistic heavy-ion collisions. The ϕ meson is an excellent probe for studying this hot and dense state of nuclear matter due to its very short lifetime, and the absence of strong interactions between muons and the surrounding hot hadronic matter makes the ϕ to dimuon decay channel particularly interesting. Since the ϕ meson is composed of a strange and antistrange quark, its nuclear modification in heavy-ion collisions may provide insight on strangeness enhancement in-medium. Additionally, the rapidity dependence of ϕ production in asymmetric heavy-ion collisions provides a unique means to study the entanglement of hot and cold nuclear matter effects. In this talk, we present the measurement of ϕ meson production and nuclear modification in asymmetric Cu+Au heavy-ion collisions at √{s}NN = 200 GeV at both forward (Cu-going direction) and backward (Au-going direction) rapidities. This material is based upon work supported by the U.S. Department of Energy (DOE), Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) award program.

Origin of the Lengshuigou porphyry-skarn Cu deposit in the Zha-Shan district, South Qinling, central China, and implications for differences between porphyry Cu and Mo deposits

NASA Astrophysics Data System (ADS)

Xie, Guiqing; Mao, Jingwen; Wang, Ruiting; Meng, Deming; Sun, Jia; Dai, Junzhi; Ren, Tao; Li, Jianbi; Zhao, Haijie

2017-04-01

Porphyry Cu and Mo deposits are two economically important types of metal deposits worldwide, but factors controlling their difference remain enigmatic. Compared with the well-studied large porphyry Mo province in the south margin of the North China Block (S-NCB), the origin of newly discovered porphyry Cu deposits in the South Qinling (SQB) is poorly constrained. Integrated zircon LA-ICPMS U-Pb and molybdenite Re-Os ages and geological evidence indicate three stages of magmatism at Lengshuigou: (1) late Neoproterozoic (718 to 704 Ma) quartz diorite + albitite + granite association during the pre-ore stage, (2) 146 to 145 Ma granodiorite porphyry during the syn-ore stage, and (3) 145 Ma granite porphyry during the post-ore stage. Elemental and Sr-Nd isotopic evidence provide important constraints on their magma source. Pre-ore Neoproterozoic quartz diorite + albitite + granite was derived by re-melting of a mixture of crustal and juvenile mantle materials, and stronger fractional crystallization was involved in these ore-hosting intrusions than in contemporary granitoids hosted in the Douling Group. Syn-ore granodiorite porphyry was derived from mantle-derived magma with contributions from different proportions of crustal components. Post-ore granite porphyry was derived mainly from a crustal source. Nearly contemporaneous porphyry Cu and Mo systems were identified in Qinling Province, including the 147-139 Ma porphyry Mo systems in the S-NCB and 150-146 Ma porphyry Cu systems in the SQB. Granitic stocks related to porphyry Cu systems in the SQB are characterized by moderate SiO2 contents (58.01-69.07 %) and less radiogenic Nd-Hf isotopes (ɛNd(t) = -3.8 to -6.3, ɛHf(t) = -4.5 to +1.6), whereas the granitic stocks related to porphyry Mo deposits in the S-NCB have high SiO2 concentrations (64.00-76.00 %) and more radiogenic Nd-Hf isotopes (ɛNd(t) = -18.0 to -11.6, ɛHf(t) = -26.3 to -13.5). In addition, molybdenite from the Chigou and Lengshuigou porphyry Cu

The late Oligocene Cevizlidere Cu-Au-Mo deposit, Tunceli Province, eastern Turkey

NASA Astrophysics Data System (ADS)

İmer, Ali; Richards, Jeremy P.; Creaser, Robert A.; Spell, Terry L.

2015-02-01

The Cevizlidere deposit, located in the Tunceli Province of eastern Anatolia, is the largest porphyry Cu-Au-Mo system in Turkey. The deposit is spatially related to a composite stock, which was emplaced into Paleozoic limestones and Paleogene andesitic rocks to the southeast of the Munzur mountains, near the southwestern margin of the Ovacık pull-apart basin. The host plutonic rocks at Cevizlidere are porphyritic, medium-K calc-alkaline diorites and granodiorites. 40Ar/39Ar incremental step-heating analysis of two igneous biotite separates obtained from syn-mineral diorite porphyry yielded late Oligocene cooling ages of 25.49 ± 0.10 and 25.10 ± 0.14 Ma, whereas hydrothermal biotite yielded an age of 24.73 ± 0.08 Ma. Re-Os ages obtained from two molybdenite separates (24.90 ± 0.10 and 24.78 ± 0.10 Ma) indicate that porphyry-style alteration and mineralization developed shortly after magma emplacement. The whole-rock geochemical composition of the Cevizlidere porphyry intrusions is consistent with derivation from partial melting of the metasomatized supra-subduction zone mantle. However, based on regional tectonic reconstructions, Oligocene magmatic activity in this area appears to be related to a major kinematic reorganization that took place at around 25 Ma, during the switch from subduction to collisional tectonics in eastern Anatolia. This kinematic switch may be attributed to break-off of the Southern Neo-Tethys oceanic slab prior to the Arabia-Eurasia continent-continent collision (~12-10 Ma) following widespread middle Eocene (50-43 Ma) arc/back-arc magmatism. In this respect, the subduction-related tectonic setting of the late Oligocene Cevizlidere porphyry deposit is similar to that of the middle Eocene Çöpler epithermal Au deposit. The late timing of Cevizlidere with respect to the Southern Neo-Tethys subduction may be comparable to some early to late Miocene porphyry-epithermal systems that lie within the contiguous Urumieh-Dokhtar belt in central

Metal-ligand bond directionality in the M2-NH3 complexes (M = Cu, Ag and Au)

NASA Astrophysics Data System (ADS)

Eskandari, K.; Ebadinejad, F.

2018-05-01

The metal-ligand bonds in the M2-NH3 complexes (M = Au, Ag and Cu) are directional and the M-M-N angles tend to be linear. Natural energy decomposition analysis (NEDA) and localised molecular orbital energy decomposition analysis (LMOEDA) approaches indicate that the metal-ligand bonds in these complexes are mainly electrostatic in nature, however, the electrostatic is not the cause of the linearity of M-M-N arrangements. Instead, NEDA shows that the charge transfer and core repulsion are mainly responsible for the directionality of these bonds. In the LMOEDA point of view, the repulsion term is the main reason for the linearity of these complexes. Interacting quantum atoms (IQA) analysis shows that inter-atomic and inter-fragment interactions favour the nonlinear arrangements; however, these terms are compensated by the atomic self-energies, which stabilise the linear structure.

Pseudomorphic to orthomorphic growth of Fe films on Cu3Au(001)

NASA Astrophysics Data System (ADS)

Bruno, F.; Terreni, S.; Floreano, L.; Cossaro, A.; Cvetko, D.; Luches, P.; Mattera, L.; Morgante, A.; Moroni, R.; Repetto, M.; Verdini, A.; Canepa, M.

2002-06-01

The structure of Fe films grown on the (001) surface of a Cu3Au single crystal at room temperature has been investigated by means of grazing incidence x-ray diffraction (GIXRD) and photo/Auger-electron diffraction (ED) as a function of thickness in the (3-36)-Å range. The combination of GIXRD and ED allows one to obtain quantitative information on the in-plane spacing a from the former technique, and the ratio between the vertical spacing c and a, from the latter one. At low coverage the film grows pseudomorphic to the face-centered-cubic substrate. The experimental results obtained on a film of 8 Å thickness clearly indicate the overcoming of the limit for pseudomorphic growth. Above this limit the film is characterized by the coexistence of the pseudomorphic phase with another tetragonally strained phase γ, which falls on the epitaxial line of ferromagnetic face-centered cubic Fe. Finally, the development of a body-centered phase α, whose unit cell is rotated by 45° with respect to the substrate one, has been clearly observed at ~17 Å. α is the dominating phase for film thickness above ~25 Å and its lattice constant evolves towards the orthomorphic phase in strict quantitative agreement with epitaxial curves calculated for body-centered tetragonal iron phases.

Relativistic Effects and Gold Site Distributions: Synthesis, Structure, and Bonding in a Polar Intermetallic Na6Cd16Au7

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samal, Saroj L.; Corbett, John D.

Na{sub 6}Cd{sub 16}Au{sub 7} has been synthesized via typical high-temperature reactions, and its structure refined by single crystal X-ray diffraction as cubic, Fm{bar 3}m, a = 13.589(1) {angstrom}, Z = 4. The structure consists of Cd{sub 8} tetrahedral star (TS) building blocks that are face capped by six shared gold (Au2) vertexes and further diagonally bridged via Au1 to generate an orthogonal, three-dimensional framework [Cd{sub 8}(Au2){sub 6/2}(Au1){sub 4/8}], an ordered ternary derivative of Mn{sub 6}Th{sub 23}. Linear muffin-tin-orbital (LMTO)-atomic sphere approximation (ASA) electronic structure calculations indicate that Na{sub 6}Cd{sub 16}Au{sub 7} is metallic and that {approx}76% of the total crystalmore » orbital Hamilton populations (-ICOHP) originate from polar Cd-Au bonding with 18% more from fewer Cd-Cd contacts. Na{sub 6}Cd{sub 16}Au{sub 7} (45 valence electron count (vec)) is isotypic with the older electron-richer Mg{sub 6}Cu{sub 16}Si{sub 7} (56 vec) in which the atom types are switched and bonding characteristics among the network elements are altered considerably (Si for Au, Cu for Cd, Mg for Na). The earlier and more electronegative element Au now occupies the Si site, in accord with the larger relativistic bonding contributions from polar Cd-Au versus Cu-Si bonds with the neighboring Cd in the former Cu positions. Substantial electronic differences in partial densities-of-states (PDOS) and COHP data for all atoms emphasize these. Strong contributions of nearby Au 5d{sup 10} to bonding states without altering the formal vec are the likely origin of these effects.« less

Timing of porphyry (Cu-Mo) and base metal (Zn-Pb-Ag-Cu) mineralisation in a magmatic-hydrothermal system—Morococha district, Peru

NASA Astrophysics Data System (ADS)

Catchpole, Honza; Kouzmanov, Kalin; Bendezú, Aldo; Ovtcharova, Maria; Spikings, Richard; Stein, Holly; Fontboté, Lluís

2015-12-01

The Morococha district in central Peru is characterised by economically important Cordilleran polymetallic (Zn-Pb-Ag-Cu) vein and replacement bodies and the large Toromocho porphyry Cu-Mo deposit in its centre. U-Pb, Re-Os, and 40Ar/39Ar geochronology data for various porphyry-related hydrothermal mineralisation styles record a 3.5-Ma multi-stage history of magmatic-hydrothermal activity in the district. In the late Miocene, three individual magmatic-hydrothermal centres were active: the Codiciada, Toromocho, and Ticlio centres, each separated in time and space. The Codiciada centre is the oldest magmatic-hydrothermal system in the district and consists of a composite porphyry stock associated with anhydrous skarn and quartz-molybdenite veins. The hydrothermal events are recorded by a titanite U-Pb age at 9.3 ± 0.2 Ma and a molybdenite Re-Os age at 9.26 ± 0.03 Ma. These ages are indistinguishable from zircon U-Pb ages for porphyry intrusions of the composite stock and indicate a time span of 0.2 Ma for magmatic-hydrothermal activity. The small Ticlio magmatic-hydrothermal centre in the west of the district has a maximum duration of 0.3 Ma, ranging from porphyry emplacement to porphyry mineralisation at 8.04 ± 0.14 Ma (40Ar/39Ar muscovite cooling age). The Toromocho magmatic-hydrothermal centre has a minimum of five recorded porphyry intrusions that span a total of 1.3 Ma and is responsible for the formation of the giant Toromocho Cu-Mo deposit. At least two hydrothermal pulses are identified. Post-dating a first pulse of molybdenite mineralisation, wide-spread hydrous skarn covers an area of over 6 km2 and is recorded by five 40Ar/39Ar cooling ages at 7.2-6.8 Ma. These ages mark the end of the slowly cooling and long-lived Toromocho magmatic-hydrothermal centre soon after last magmatic activity at 7.26 ± 0.02 Ma. District-wide (50 km2) Cordilleran base metal vein and replacement bodies post-date the youngest recorded porphyry mineralisation event at Toromocho

Dynamics of copper-phthalocyanine molecules on Au/Ge(001)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sotthewes, K.; Heimbuch, R.; Zandvliet, H. J. W.

2015-10-07

Spatially resolved current-time scanning tunneling spectroscopy combined with current-distance spectroscopy has been used to characterize the dynamic behavior of copper-phthalocyanine (CuPc) molecules adsorbed on a Au-modified Ge(001) surface. The analyzed CuPc molecules are adsorbed in a “molecular bridge” configuration, where two benzopyrrole groups (lobes) are connected to a Au-induced nanowire, whereas the other two lobes are connected to the adjacent nanowire. Three types of lobe configurations are found: a bright lobe, a dim lobe, and a fuzzy lobe. The dim and fuzzy lobes exhibit a well-defined switching behavior between two discrete levels, while the bright lobe shows a broad oscillationmore » band. The observed dynamic behavior is induced by electrons that are injected into the LUMO+1 orbital of the CuPc molecule. By precisely adjusting the tip-molecule distance, the switching frequency of the lobes can be tuned accurately.« less

Contrasting fluids and reservoirs in the contiguous Marcona and Mina Justa iron oxide-Cu (-Ag-Au) deposits, south-central Perú

NASA Astrophysics Data System (ADS)

Chen, Huayong; Kyser, T. Kurtis; Clark, Alan H.

2011-10-01

The Marcona-Mina Justa deposit cluster, hosted by Lower Paleozoic metaclastic rocks and Middle Jurassic shallow marine andesites, incorporates the most important known magnetite mineralization in the Andes at Marcona (1.9 Gt at 55.4% Fe and 0.12% Cu) and one of the few major iron oxide-copper-gold (IOCG) deposits with economic Cu grades (346.6 Mt at 0.71% Cu, 3.8 g/t Ag and 0.03 g/t Au) at Mina Justa. The Middle Jurassic Marcona deposit is centred in Ica Department, Perú, and the Lower Cretaceous Mina Justa Cu (Ag, Au) prospect is located 3-4 km to the northeast. New fluid inclusion studies, including laser ablation time-of-flight inductively coupled plasma mass spectrometry (LA-TOF-ICPMS) analysis, integrated with sulphur, oxygen, hydrogen and carbon isotope analyses of minerals with well-defined paragenetic relationships, clarify the nature and origin of the hydrothermal fluid responsible for these contiguous but genetically contrasted deposits. At Marcona, early, sulphide-free stage M-III magnetite-biotite-calcic amphibole assemblages are inferred to have crystallized from a 700-800°C Fe oxide melt with a δ18O value from +5.2‰ to +7.7‰. Stage M-IV magnetite-phlogopite-calcic amphibole-sulphide assemblages were subsequently precipitated from 430-600°C aqueous fluids with dominantly magmatic isotopic compositions (δ34S = +0.8‰ to +5.9‰; δ18O = +9.6‰ to +12.2‰; δD = -73‰ to -43‰; and δ13C = -3.3‰). Stages M-III and M-IV account for over 95% of the magnetite mineralization at Marcona. Subsequent non-economic, lower temperature sulphide-calcite-amphibole assemblages (stage M-V) were deposited from fluids with similar δ34S (+1.8‰ to +5.0‰), δ18O (+10.1‰ to +12.5‰) and δ13C (-3.4‰), but higher δD values (average -8‰). Several groups of lower (<200°C, with a mode at 120°C) and higher temperature (>200°C) fluids can be recognized in the main polymetallic (Cu, Zn, Pb) sulphide stage M-V and may record the involvement of

High REE and Y concentrations in Co-Cu-Au ores of the Blackbird district, Idaho

USGS Publications Warehouse

Slack, J.F.

2006-01-01

Analysis of 11 samples of strata-bound Co-Cu-Au ore from the Blackbird district in Idaho shows previously unknown high concentrations of rare earth elements (REE) and Y, averaging 0.53 wt percent ???REE + Y oxides. Scanning electron microscopy indicates REE and Y residence in monazite, xenotime, and allanite that form complex intergrowths with cobaltite, suggesting coeval Co and REE + Y mineralization during the Mesoproterozoic. Occurrence of high REE and Y concentrations in the Blackbird ores, together with previously documented saline-rich fluid inclusions and Cl-rich biotite, suggest that these are not volcanogenic massive sulfide or sedimentary exhalative deposits but instead are iron oxide-copper-gold (IOCG) deposits. Other strata-bound Co deposits of Proterozoic age in the North American Cordillera and elsewhere in the world may have potential for REE and Y resources. IOCG deposits with abundant light REE should also be evaluated for possible unrecognized heavy REE and Y mineralization. ?? 2006 by Economic Geology.

High-resolution Auger-electron spectroscopy induced by positron annihilation on Fe, Ni, Cu, Zn, Pd, and Au

NASA Astrophysics Data System (ADS)

Hugenschmidt, C.; Mayer, J.; Schreckenbach, K.

2010-04-01

Positron annihilation induced Auger electron spectroscopy (PAES) enables almost background free, non-destructive surface analysis with high surface selectivity. The Auger-spectrometer at the high intense positron source NEPOMUC now allows to record positron annihilation induced Auger spectra within a short data acquisition time of 10-80 minutes. With a new hemispherical electron energy analyzer and due to the exceptional peak to noise ratio, we succeeded to measure Auger-transitions such as the M2,3V V double peak of nickel with high energy resolution. The relative Auger-electron intensities are obtained by the analysis of the recorded positron annihilation induced Auger spectra for the surfaces of Fe, Ni, Cu, Pd and Au. It is demonstrated, that high-resolution PAES allows to determine experimentally the relative surface core annihilation probability of various atomic levels.

Comparison of Low Energy CVV Auger transitions in Cu and Au (100) using Measured and estimated values

NASA Astrophysics Data System (ADS)

Shastry, K.; Mukherjee, S. F.; Satyal, S.; Joglekar, P. V.; Weiss, A. H.

2011-10-01

Low energy Auger lineshapes are difficult to measure because they sit on a large background due to secondary electrons arising from loss processes unrelated to the Auger mechanism. In this poster we discuss the implications of our PAES measurements of the ratio of the integrated Auger Peak and integrated low energy tail (LET) intensities for comparisons between theoretical and measured values of the Auger intensities. The experiments were carried out at university of Texas at Arlington on Cu (100) and Au (100) crystals. Our conclusions regarding the importance of the LET in determining the ratio of electrons in the Auger peak to the number of initial core holes are discussed in light of the electron stimulated Auger results obtained by Seah et.al using monte carlo simulations on various elements.

Growth of copper phthalocyanine rods on Au plasmon electrodes through micelle disruption methods.

PubMed

Chen, Wei-Hung; Ko, Wen-Yin; Chen, Ying-Shiou; Cheng, Ching-Yuan; Chan, Chi-Ming; Lin, Kuan-Jiuh

2010-02-16

To improve the efficiency of the photocurrent conversion process, we have utilized copper phthalocyanine (CuPc) rods, which are capable of enhancing the interfacial area of electron transport and plasmonic gold nanoparticles (Au NPs), which can increase the separation and photogeneration of excitons, to produce a more effective system. In-plane horizontal CuPc rods, with diameters ranging from 0.2 to 1.5 microm, were electrodeposited onto the surface of plasmonic (Au NP) monolayers predeposited onto ITO substrates through electrolytic micelle disruption (EMD) methods.

Ni, Cu, Au, and platinum-group element contents of sulphides associated with intraplate magmatism: A synthesis

USGS Publications Warehouse

Barnes, S.-J.; Zientek, M.L.; Severson, M.J.

1997-01-01

The tectonic setting of intraplate magmas, typically a plume intersecting a rift, is ideal for the development of Ni - Cu - platinum-group element-bearing sulphides. The plume transports metal-rich magmas close to the mantle - crust boundary. The interaction of the rift and plume permits rapid transport of the magma into the crust, thus ensuring that no sulphides are lost from the magma en route to the crust. The rift may contain sediments which could provide the sulphur necessary to bring about sulphide saturation in the magmas. The plume provides large volumes of mafic magma; thus any sulphides that form can collect metals from a large volume of magma and consequently the sulphides will be metal rich. The large volume of magma provides sufficient heat to release large quantities of S from the crust, thus providing sufficient S to form a large sulphide deposit. The composition of the sulphides varies on a number of scales: (i) there is a variation between geographic areas, in which sulphides from the Noril'sk - Talnakh area are the richest in metals and those from the Muskox intrusion are poorest in metals; (ii) there is a variation between textural types of sulphides, in which disseminated sulphides are generally richer in metals than the associated massive and matrix sulphides; and (iii) the massive and matrix sulphides show a much wider range of compositions than the disseminated sulphides, and on the basis of their Ni/Cu ratio the massive and matrix sulphides can be divided into Cu rich and Fe rich. The Cu-rich sulphides are also enriched in Pt, Pd, and Au; in contrast, the Fe-rich sulphides are enriched in Fe, Os, Ir, Ru, and Rh. Nickel concentrations are similar in both. Differences in the composition between the sulphides from different areas may be attributed to a combination of differences in composition of the silicate magma from which the sulphides segregated and differences in the ratio of silicate to sulphide liquid (R factors). The higher metal

Geochemical contrasts between Late Triassic ore-bearing and barren intrusions in the Weibao Cu-Pb-Zn deposit, East Kunlun Mountains, NW China: constraints from accessory minerals (zircon and apatite)

NASA Astrophysics Data System (ADS)

Zhong, Shihua; Feng, Chengyou; Seltmann, Reimar; Li, Daxin; Dai, Zhihui

2017-12-01

The Weibao copper-lead-zinc skarn deposit is located in the northern East Kunlun terrane, NW China. Igneous intrusions in this deposit consist of barren diorite porphyry (U-Pb zircon age of 232.0 ± 2.0 Ma) and ore-bearing quartz diorite and pyroxene diorite (U-Pb zircon ages of 223.3 ± 1.5 and 224.6 ± 2.9 Ma, respectively). Whole-rock major and trace element and accessory mineral (zircon and apatite) composition from these intrusions are studied to examine the different geochemical characteristics of ore-bearing and barren intrusions. Compared to the barren diorite porphyry, the ore-bearing intrusions have higher Ce4+/Ce3+ ratios of zircon and lower Mn contents of apatite, indicating higher oxidation state. Besides, apatite from the ore-bearing intrusions shows higher Cl contents and lower F/Cl ratios. These characteristics collectively suggest the higher productivity of ore-bearing quartz diorite and pyroxene diorite. When compared with ore-bearing intrusions from global porphyry Cu deposits, those from Cu-Pb-Zn skarn deposits display lower Ce4+/Ce3+ and EuN/EuN* ratios of zircon and lower Cl and higher F/Cl ratios of apatite. We conclude that these differences reflect a general geochemical feature, and that zircon and apatite composition is a sensitive tool to infer economic potential of magmas and the resulting mineralization types in intrusion-related exploration targets.

On the mechanisms of cation injection in conducting bridge memories: The case of HfO{sub 2} in contact with noble metal anodes (Au, Cu, Ag)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saadi, M.; CNRS, LTM, F-38000 Grenoble; El Manar University, LMOP, 2092 Tunis

Resistance switching is studied in HfO{sub 2} as a function of the anode metal (Au, Cu, and Ag) in view of its application to resistive memories (resistive random access memories, RRAM). Current-voltage (I-V) and current-time (I-t) characteristics are presented. For Au anodes, resistance transition is controlled by oxygen vacancies (oxygen-based resistive random access memory, OxRRAM). For Ag anodes, resistance switching is governed by cation injection (Conducting Bridge random access memory, CBRAM). Cu anodes lead to an intermediate case. I-t experiments are shown to be a valuable tool to distinguish between OxRRAM and CBRAM behaviors. A model is proposed to explainmore » the high-to-low resistance transition in CBRAMs. The model is based on the theory of low-temperature oxidation of metals (Cabrera-Mott theory). Upon electron injection, oxygen vacancies and oxygen ions are generated in the oxide. Oxygen ions are drifted to the anode, and an interfacial oxide is formed at the HfO{sub 2}/anode interface. If oxygen ion mobility is low in the interfacial oxide, a negative space charge builds-up at the HfO{sub 2}/oxide interface. This negative space charge is the source of a strong electric field across the interfacial oxide thickness, which pulls out cations from the anode (CBRAM case). Inversely, if oxygen ions migration through the interfacial oxide is important (or if the anode does not oxidize such as Au), bulk oxygen vacancies govern resistance transition (OxRRAM case).« less

Secondary ion emission from Ti, V, Cu, Ag and Au surfaces under KeV Cs + irradiation

NASA Astrophysics Data System (ADS)

van der Heide, P. A. W.

2005-02-01

Low energy mono-atomic singly charged secondary ion emissions from Ti, V, Cu, Ag and Au substrates during the initial stages of sputtering with Cs + primary ions have been studied. With the exception of the Ag - secondary ions, all exhibited exponential like correlations with the Cs induced work function changes. This, along with the lack of variations in the valence band structure around the Fermi edge, is consistent with resonance charge transfer to/from states located at the Fermi edge. The insensitivity of Ag - to work function appears to stem from the dominance of a separate ion formation process, namely charge transfer into vacant 4d states in the sputtered population, which themselves appear to be produced through collective oscillations. A similar excitation-mediated process involving different levels also appears to be active in the formation of other negatively charged transition metal ions, albeit to a much lesser degree.

Enhanced interface perpendicular magnetic anisotropy in electrodeposited Co/Au(111) layers

NASA Astrophysics Data System (ADS)

Cagnon, L.; Devolder, T.; Cortes, R.; Morrone, A.; Schmidt, J. E.; Chappert, C.; Allongue, P.

2001-03-01

This work investigates the structure and interface perpendicular magnetic anisotropy (PMA) of electrodeposited Cu/Co/Au(111) sandwiches with variable Co thickness [2-20 monolayers (ML's)]. In optimum deposition conditions, polar magneto-optical Kerr effect measurements show that the axis of easy magnetization is perpendicular to the layers for thicknesses below ca. 7.2 ML's. This value is among the best ever reported for the Cu/Co/Au(111) structure. While extended x-ray-absorption fine structure indicates that layers are hcp, in situ STM imaging suggests that magnetoelastic effects contribute significantly to PMA. The correlation observed between the strength of PMA and film structure is discussed in details.

PHENIX Measurement of B → J/ψ in Cu+Au collisions at √{sNN} = 200 GeV and in p+p collisions at 200 GeV and 510 GeV

NASA Astrophysics Data System (ADS)

da Silva, Cesar Luiz; Phenix Collaboration

2017-11-01

This study is part of the RHIC program to probe properties of the Quark-Gluon Plasma medium properties using heavy quark energy loss. Part of the control of these measurements is to understand initial production of heavy quarks and how initial conditions in nucleus collisions can alter their yields. This manuscript reports the effort made by the PHENIX collaboration to measure total B-mesons yields, by looking at the fraction of muons from non-prompt J/ψ decays at displaced vertices in p+p and Cu+Au collisions. The total cross-sections of b-quarks in 200 GeV and 510 GeV p+p collisions follow the increasing trend from fixed target experiments to high energy results from the Tevatron and the LHC. Integrated pT and centrality B-meson yields in Cu+Au integrated over transverse momentum and centrality are consistent with no nuclear modification or some enhancement, in contrast to prompt J/ψ which shows a strong suppression.

Regional setting and characteristics of the Neoproterozoic Wadi Hamama Zn-Cu-Ag-Au prospect: evidence for an intra-oceanic island arc-hosted volcanogenic hydrothermal system

NASA Astrophysics Data System (ADS)

Abd El-Rahman, Yasser; Surour, Adel A.; El-Manawi, Abdel Hamid W.; El-Dougdoug, Abdel-Monem A.; Omar, Sayed

2015-04-01

The Wadi Hamama area is a volcanogenic Zn-Cu-Au-Ag prospect. It is hosted by a Neoproterozoic bimodal-mafic sequence, which comprises basalt, dacite and rhyolite along with volcaniclastic rocks. The rocks have a low-K tholeiitic affinity and are enriched in large ion lithophile elements over high field strength elements, which indicated their formation in an intra-oceanic island arc tectonic setting. The area was intruded by a tonalite-trondhjemite body, which has an intra-oceanic island arc affinity and later by diorite, which has a cordilleran-margin geochemical affinity. These rock units were intruded by post-tectonic granite dykes, which have a within-plate geochemical signature. There is a quartz-carbonate horizon extending along the contact between the basalt and the volcaniclastic rocks, mainly banded and lapilli tuffs. This horizon is of exhalative origin and is underlain by a mushroom-shaped alteration zone extending from the horizon down to the massive basalt. The footwall alteration is characterized by a silica-rich core surrounded by a thick chlorite sheath. Both the quartz-carbonate horizon and the footwall-altered rocks enclose historical trenches and pits. Sulfide-rich core samples are enriched in Zn, relative to Cu, and in Ag, which indicates the low-temperature nature of the hydrothermal system. The prospect was affected by supergene processes, which led to the widespread occurrence of secondary copper minerals and gold enrichment relative to the leached base metals, especially Zn. The prospect formed through a limited rifting of an intra-oceanic island arc which resulted in the formation of a small-scale volcanogenic Zn-Cu-Ag-Au prospect.

Supramolecular assembly of biphenyl dicarboxylic acid on Au(1 1 1)

NASA Astrophysics Data System (ADS)

Zhu, N.; Osada, T.; Komeda, T.

2007-04-01

We investigate the structure of submonolayer film of 4,4'-biphenyl dicarboxylic acid (BDA) molecules on Au(1 1 1)-22 × √3 reconstructed surface with the use of scanning tunneling microscopy (STM). The BDA molecules form ordered structures on Au(1 1 1) surface which are commensurate with the substrate. We have concluded that the molecule-molecule interaction is mainly through hydrogen bonding formed by a straight dimer of BDA molecules. The straight dimer can be expressed as 4 s + 2 t or its six crystallographic equivalents using the unit vectors of the gold substrate of s and t. The length of hydrogen bonding (O-H-O) is estimated to be 0.31 nm assuming nearest neighbor distance of gold atoms of 0.275 nm. The ordering shows a clear contrast with the case of BDA on Cu(1 0 0) surface [S. Stepanow, N. Lin, F. Vidal, A. Landa, M. Ruben, J.V. Barth, K. Kern, Nanoletters 5 (2005) 901] in which a square type of ordering of molecules is observed by the formation of hydrogen bonding between a carboxylate (COO) and a benzene ring. The clear difference of the ordered structure on Cu(1 0 0) and Au(1 1 1) surface demonstrates that the absence (presence) of deprotonation of carboxyl group of BDA molecule on Au(1 1 1) (Cu(1 0 0)) switches the straight and square type ordering of BDA molecules.

Chelator-Free 64Cu-Integrated Gold Nanomaterials for Positron Emission Tomography Imaging Guided Photothermal Cancer Therapy

PubMed Central

2015-01-01

Using positron emission tomography (PET) imaging to monitor and quantitatively analyze the delivery and localization of Au nanomaterials (NMs), a widely used photothermal agent, is essential to optimize therapeutic protocols to achieve individualized medicine and avoid side effects. Coupling radiometals to Au NMs via a chelator faces the challenges of possible detachment of the radiometals as well as surface property changes of the NMs. In this study, we reported a simple and general chelator-free 64Cu radiolabeling method by chemically reducing 64Cu on the surface of polyethylene glycol (PEG)-stabilized Au NMs regardless of their shape and size. Our 64Cu-integrated NMs are proved to be radiochemically stable and can provide an accurate and sensitive localization of NMs through noninvasive PET imaging. We further integrated 64Cu onto arginine-glycine-aspartic acid (RGD) peptide modified Au nanorods (NRs) for tumor theranostic application. These NRs showed high tumor targeting ability in a U87MG glioblastoma xenograft model and were successfully used for PET image-guided photothermal therapy. PMID:25019252

USGS exploration geochemistry studies at the Pebble porphyry Cu-Au-Mo deposit, Alaska-pdf of presentation

USGS Publications Warehouse

Eppinger, Robert G.; Kelley, Karen D.; Fey, David L.; Giles, Stuart A.; Minsley, Burke J.; Smith, Steven M.

2010-01-01

From 2007 through 2010, scientists in the U.S. Geological Survey (USGS) have been conducting exploration-oriented geochemical and geophysical studies in the region surrounding the giant Pebble porphyry Cu-Au-Mo deposit in southwestern Alaska. The Cretaceous Pebble deposit is concealed under tundra, glacial till, and Tertiary cover rocks, and is undisturbed except for numerous exploration drill holes. These USGS studies are part of a nation-wide research project on evaluating and detecting concealed mineral resources. This report focuses on exploration geochemistry and comprises illustrations and associated notes that were presented as a case study in a workshop on this topic. The workshop, organized by L.G. Closs and R. Glanzman, is called 'Geochemistry in Mineral Exploration and Development,' presented by the Society of Economic Geologists at a technical conference entitled 'The Challenge of Finding New Mineral Resources: Global Metallogeny, Integrative Exploration and New Discoveries,' held at Keystone, Colorado, October 2-5, 2010.

Immobilization of gold nanoclusters inside porous electrospun fibers for selective detection of Cu(II): A strategic approach to shielding pristine performance

NASA Astrophysics Data System (ADS)

Senthamizhan, Anitha; Celebioglu, Asli; Balusamy, Brabu; Uyar, Tamer

2015-10-01

Here, a distinct demonstration of highly sensitive and selective detection of copper (Cu2+) in a vastly porous cellulose acetate fibers (pCAF) has been carried out using dithiothreitol capped gold nanocluster (DTT.AuNC) as fluorescent probe. A careful optimization of all potential factors affecting the performance of the probe for effective detection of Cu2+ were studied and the resultant sensor strip exhibiting unique features including high stability, retained parent fluorescence nature and reproducibility. The visual colorimetric detection of Cu2+ in water, presenting the selective sensing performance towards Cu2+ ions over Zn2+, Cd2+ and Hg2+ under UV light in naked eye, contrast to other metal ions that didn’t significantly produce such a change. The comparative sensing performance of DTT.AuNC@pCAF, keeping the nonporous CA fiber (DTT.AuNC@nCAF) as a support matrix has been demonstrated. The resulting weak response of DTT.AuNC@nCAF denotes the lack of ligand protection leading to the poor coordination ability with Cu2+. The determined detection limit (50 ppb) is far lower than the maximum level of Cu2+ in drinking water (1.3 ppm) set by U.S. Environmental Protection Agency (EPA). An interesting find from this study has been the specific oxidation nature between Cu2+ and DTT.AuNC, offering solid evidence for selective sensors.

PET and NIR Optical Imaging Using Self-Illuminating 64Cu-Doped Chelator-Free Gold Nanoclusters

PubMed Central

Hu, Hao; Huang, Peng; Weiss, Orit Jacobson; Yan, Xuefeng; Yue, Xuyi; Zhang, Molly Gu; Tang, Yuxia; Nie, Liming; Ma, Ying; Niu, Gang; Wu, Kaichun; Chen, Xiaoyuan

2014-01-01

Self-illuminating fluorescence imaging without autofluorescence background interference has recently aroused more research interests in molecular imaging. Currently, only a few self-illuminating probes were developed, based mainly on toxic quantum dots such as CdSe, CdTe. Herein, we report a novel design of nontoxic self-illuminating gold nanocluster (64Cu-doped AuNCs) for dual-modality positron emission tomography (PET) and near-infrared (NIR) fluorescence imaging based on Cerenkov resonance energy transfer (CRET). PET radionuclide 64Cu was introduced by a chelator-free doping method, which played dual roles as the energy donor and the PET imaging source. Meanwhile, AuNCs acted as the energy acceptor for NIR fluorescence imaging. 64Cu-doped AuNCs exhibited efficient CRET-NIR and PET imaging both in vitro and in vivo. In a U87MG glioblastoma xenograft model, 64Cu-doped AuNCs showed high tumor uptake (14.9%ID/g at 18 h) and produced satisfactory tumor self-illuminating NIR images in the absence of external excitation. This self-illuminating nanocluster with non-toxicity and good biocompatibility can be employed as a novel imaging contrast agent for biomedical applications, especially for molecular imaging. PMID:25224367

PET and NIR optical imaging using self-illuminating (64)Cu-doped chelator-free gold nanoclusters.

PubMed

Hu, Hao; Huang, Peng; Weiss, Orit Jacobson; Yan, Xuefeng; Yue, Xuyi; Zhang, Molly Gu; Tang, Yuxia; Nie, Liming; Ma, Ying; Niu, Gang; Wu, Kaichun; Chen, Xiaoyuan

2014-12-01

Self-illuminating fluorescence imaging without autofluorescence background interference has recently aroused more research interests in molecular imaging. Currently, only a few self-illuminating probes were developed, based mainly on toxic quantum dots such as CdSe, CdTe. Herein, we report a novel design of nontoxic self-illuminating gold nanocluster ((64)Cu-doped AuNCs) for dual-modality positron emission tomography (PET) and near-infrared (NIR) fluorescence imaging based on Cerenkov resonance energy transfer (CRET). PET radionuclide (64)Cu was introduced by a chelator-free doping method, which played dual roles as the energy donor and the PET imaging source. Meanwhile, AuNCs acted as the energy acceptor for NIR fluorescence imaging. (64)Cu-doped AuNCs exhibited efficient CRET-NIR and PET imaging both in vitro and in vivo. In a U87MG glioblastoma xenograft model, (64)Cu-doped AuNCs showed high tumor uptake (14.9 %ID/g at 18 h) and produced satisfactory tumor self-illuminating NIR images in the absence of external excitation. This self-illuminating nanocluster with non-toxicity and good biocompatibility can be employed as a novel imaging contrast agent for biomedical applications, especially for molecular imaging. Published by Elsevier Ltd.

Mineral potential tracts for polymetallic Pb-Zn-Cu vein deposits (phase V, deliverable 71): Chapter I in Second projet de renforcement institutionnel du secteur minier de la République Islamique de Mauritanie (PRISM-II)

USGS Publications Warehouse

Beaudoin, Georges

2015-01-01

In Mauritania, mineral occurrences of the polymetallic Pb-Zn-Cu vein deposit type are found near the Florence-El Khdar shear zone in northeast Mauritania. The deposits visited were deemed representative of other similar occurrences and consist of quartz veins with trace sulfides. The low sulfide and Pb-Zn-Cu content in the quartz veins is unlike producing polymetallic Pb-Zn-Cu vein deposits, such that the veins are not considered to belong to this deposit type. Mineral potential tracts for polymetallic Pb-ZnCu veins are highly speculative considering the lack of known mineralization belonging to this deposit type. Mineral potential tracts for polymetallic Pb-Zn-Cu veins are associated with and surround major shear zones in the Rgueïbat Shield and zones of complex faulting in the southern Mauritanides, at the exclusion of the imbricated thrust faults that are not considered favorable for this deposit type. No skarn and replacement deposits have been documented in Mauritania and the low mineral potential is indicated by lack of causative Mesozoic and Cenozoic mafic to felsic stocks.

Geodiversity of hydrothermal processes along the Mid-Atlantic Ridge and ultramafic-hosted mineralization: A new type of oceanic Cu-Zn-Co-Au volcanogenic massive sulfide deposit

NASA Astrophysics Data System (ADS)

Fouquet, Yves; Cambon, Pierre; Etoubleau, Joël; Charlou, Jean Luc; Ondréas, Hélène; Barriga, Fernando J. A. S.; Cherkashov, Georgy; Semkova, Tatiana; Poroshina, Irina; Bohn, M.; Donval, Jean Pierre; Henry, Katell; Murphy, Pamela; Rouxel, Olivier

Several hydrothermal deposits associated with ultramafic rocks have recently been found along slow spreading ridges with a low magmatic budget. Three preferential settings are identified: (1) rift valley walls near the amagmatic ends of ridge segments; (2) nontransform offsets; and (3) ultramafic domes at inside corners of ridge transform-fault intersections. The exposed mantle at these sites is often interpreted to be a detachment fault. Hydrothermal cells in ultramafic rocks may be driven by regional heat flow, cooling gabbroic intrusions, and exothermic heat produced during serpentinization. Along the Mid-Atlantic Ridge (MAR), hydrothermal deposits in ultramafic rocks include the following: (1) sulfide mounds related to high-temperature low-pH fluids (Logatchev, Rainbow, and Ashadze); (2) carbonate chimneys related to low-temperature, high-pH fluids (Lost City); (3) low-temperature diffuse venting and high-methane discharge associated with silica, minor sulfides, manganese oxides, and pervasive alteration (Saldanha); and (4) stockwork quartz veins with sulfides at the base of detachment faults (15°05'N). These settings are closely linked to preferential circulation of fluid along permeable detachment faults. Compared to mineralization in basaltic environments, sulfide deposits associated with ultramafic rocks are enriched in Cu, Zn, Co, Au, and Ni. Gold has a bimodal distribution in low-temperature Zn-rich and in high-temperature Cu-rich mineral assemblages. The Cu-Zn-Co-Au deposits along the MAR seem to be more abundant than in ophiolites on land. This may be because ultramafic-hosted volcanogenic massive sulfide deposits on slow spreading ridges are usually not accreted to continental margins during obduction and may constitute a specific marine type of mineralization.

Origin of dioritic magma and its contribution to porphyry Cu-Au mineralization at Pulang in the Yidun arc, eastern Tibet

NASA Astrophysics Data System (ADS)

Cao, Kang; Yang, Zhi-Ming; Xu, Ji-Feng; Fu, Bin; Li, Wei-Kai; Sun, Mao-Yu

2018-04-01

The giant Pulang porphyry Cu-Au deposit in the Yidun arc, eastern Tibet, formed due to westward subduction of the Garze-Litang oceanic plate in the Late Triassic. The deposit is hosted in an intrusive complex comprising primarily coarse-grained quartz diorite and cored quartz monzonite. Here, we investigate a suite of simultaneous (216.6 ± 1.9 Ma) diorite porphyries within the complex. The diorite porphyries are geochemically similar to mafic magmatic enclaves (MME) hosted in coarse-grained quartz diorite, and both are characterized by low SiO2 (59.4-63.0 wt%) and high total alkali (Na2O + K2O = 7.0-9.2 wt%), K2O (3.5-6.4 wt%), MgO (3.2-5.5 wt%), and compatible trace element (e.g., Cr = 72-149 ppm) concentrations. They are enriched in large-ion lithophile and light rare earth elements (LILE and LREE, respectively), but depleted in high field-strength and heavy rare earth elements (HFSE and HREE, respectively), and yield variably high (La/Yb)N ratios (17-126, average 65) with weak to negligible Eu anomalies. Furthermore, they yield low (87Sr/86Sr)i ratios (0.7054-0.7067), weakly negative εNd(t) (-2.8 to -0.8) values, and variable zircon εHf(t) (-5.4 to +0.8) and δ18O (6.0‰-6.7‰) values. These geochemical features indicate that the diorite porphyry and MME formed through crustal assimilation of a magma produced during low-degree partial melting of metasomatized phlogopite-rich subcontinental lithospheric mantle. In contrast, the coarse-grained quartz diorite and quartz monzonite have relatively high concentrations of SiO2 (61.1-65.3 wt%), K2O (4.1-5.4 wt%), and total alkali (Na2O + K2O = 7.1-8.1 wt%), and low concentrations of MgO (generally <3.0 wt%) and compatible trace elements (e.g., Cr = 38-61 ppm). They yield high Sr/Y ratios (50-63) that indicate an adakitic affinity, and are enriched in LILE, depleted in HFSE, and yield lower (La/Yb)N values (13-20, average 17) than the diorite porphyry and MME. They yield low (87Sr/86Sr)i ratios (0

In Vivo Neural Recording and Electrochemical Performance of Microelectrode Arrays Modified by Rough-Surfaced AuPt Alloy Nanoparticles with Nanoporosity

PubMed Central

Zhao, Zongya; Gong, Ruxue; Zheng, Liang; Wang, Jue

2016-01-01

In order to reduce the impedance and improve in vivo neural recording performance of our developed Michigan type silicon electrodes, rough-surfaced AuPt alloy nanoparticles with nanoporosity were deposited on gold microelectrode sites through electro-co-deposition of Au-Pt-Cu alloy nanoparticles, followed by chemical dealloying Cu. The AuPt alloy nanoparticles modified gold microelectrode sites were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and in vivo neural recording experiment. The SEM images showed that the prepared AuPt alloy nanoparticles exhibited cauliflower-like shapes and possessed very rough surfaces with many different sizes of pores. Average impedance of rough-surfaced AuPt alloy nanoparticles modified sites was 0.23 MΩ at 1 kHz, which was only 4.7% of that of bare gold microelectrode sites (4.9 MΩ), and corresponding in vitro background noise in the range of 1 Hz to 7500 Hz decreased to 7.5 μVrms from 34.1 μVrms at bare gold microelectrode sites. Spontaneous spike signal recording was used to evaluate in vivo neural recording performance of modified microelectrode sites, and results showed that rough-surfaced AuPt alloy nanoparticles modified microelectrode sites exhibited higher average spike signal-to-noise ratio (SNR) of 4.8 in lateral globus pallidus (GPe) due to lower background noise compared to control microelectrodes. Electro-co-deposition of Au-Pt-Cu alloy nanoparticles combined with chemical dealloying Cu was a convenient way for increasing the effective surface area of microelectrode sites, which could reduce electrode impedance and improve the quality of in vivo spike signal recording. PMID:27827893

Electrochemiluminescence quenching of luminol by CuS in situ grown on reduced graphene oxide for detection of N-terminal pro-brain natriuretic peptide.

PubMed

Li, Xiaojian; Lu, Peng; Wu, Bin; Wang, Yaoguang; Wang, Huan; Du, Bin; Pang, Xuehui; Wei, Qin

2018-07-30

A novel electrochemiluminescence (ECL) signal-off strategy based on CuS in situ grown on reduced graphene oxide (CuS-rGO) quenching luminol/H 2 O 2 system was firstly proposed. Luminol was grafted on the surface of Au@Fe 3 O 4 -Cu 3 (PO 4 ) 2 nanoflowers (Luminol-Au@Fe 3 O 4 -Cu 3 (PO 4 ) 2 ) which exhibited excellent catalytic effect towards the reduction of H 2 O 2 to enhance the ECL intensity of luminol. Cu 3 (PO 4 ) 2 nanoflowers showed large surface area which can immobilize more Fe 3 O 4 and Au nanoparticles. The quenching mechanism of CuS-rGO was due to ECL resonance energy transfer (RET). The spectral overlap between fluorescence spectrum of Luminol-Au@Fe 3 O 4 -Cu 3 (PO 4 ) 2 and UV-vis absorption spectrum of CuS-rGO revealed that resonance energy transfer was possible. Au nanoparticles were immobilized on the surface of CuS-rGO to capture secondary antibodies. After a sandwich-type immunoreaction, a remarkable decrease of ECL signal was observed. Under the optimal conditions, the immunosensor showed excellent performance for N-terminal pro-brain natriuretic peptide (NT-proBNP) detection with a wide detection range from 0.5 pg mL -1 to 20 ng mL -1 and a low detection limit of 0.12 pg mL -1 (S/N = 3). The prepared NT-proBNP immunosensor displayed high sensitivity, excellent stability and good specificity. Copyright © 2018 Elsevier B.V. All rights reserved.

Non-aggregation based label free colorimetric sensor for the detection of Cu2+ based on catalyzing etching of gold nanorods by dissolve oxygen.

PubMed

Liu, Jia-Ming; Jiao, Li; Lin, Li-Ping; Cui, Ma-Lin; Wang, Xin-Xing; Zhang, Li-Hong; Zheng, Zhi-Yong; Jiang, Shu-Lian

2013-12-15

A label-free non-aggregation colorimetric sensor has been designed for the detection of Cu(2+), based on Cu(2+) catalyzing etching of gold nanorods (AuNRs) along longitudinal axis induced by dissolve oxygen in the presence of S2O3(2-), which caused the aspect ratio (length/width) of AuNRs to decrease and the color of the solution to distinctly change. The linear range and the detection limit (LD, calculated by 10 Sb/k, n=11) of this sensor were 0.080-4.8 µM Cu(2+) and 0.22 µM Cu(2+), respectively. This sensor has been utilized to detect Cu(2+) in tap water and human serum samples with the results agreeing well with those of inductively coupled plasma-mass spectroscopy (ICP-MS), showing its remarkable practicality. In order to prove the possibility of catalyzing AuNRs non-aggregation colorimetric sensor for the detection of Cu(2+), the morphological structures of AuNRs were characterized by high resolution transmission electron microscopy (HRTEM) and the sensing mechanism of colorimetric sensor for the detection of Cu(2+) was also discussed. © 2013 Elsevier B.V. All rights reserved.

Strata-bound Fe-Co-Cu-Au-Bi-Y-REE deposits of the Idaho Cobalt Belt: Multistage hydrothermal mineralization in a magmatic-related iron oxide copper-gold system

USGS Publications Warehouse

Slack, John F.

2012-01-01

Mineralogical and geochemical studies of strata-bound Fe-Co-Cu-Au-Bi-Y-rare-earth element (REE) deposits of the Idaho cobalt belt in east-central Idaho provide evidence of multistage epigenetic mineralization by magmatic-hydrothermal processes in an iron oxide copper-gold (IOCG) system. Deposits of the Idaho cobalt belt comprise three types: (1) strata-bound sulfide lenses in the Blackbird district, which are cobaltite and, less commonly, chalcopyrite rich with locally abundant gold, native bismuth, bismuthinite, xenotime, allanite, monazite, and the Be-rich silicate gadolinite-(Y), with sparse uraninite, stannite, and Bi tellurides, in a gangue of quartz, chlorite, biotite, muscovite, garnet, tourmaline, chloritoid, and/or siderite, with locally abundant fluorapatite or magnetite; (2) discordant tourmalinized breccias in the Blackbird district that in places have concentrations of cobaltite, chalcopyrite, gold, and xenotime; and (3) strata-bound magnetite-rich lenses in the Iron Creek area, which contain cobaltiferous pyrite and locally sparse chalcopyrite or xenotime. Most sulfide-rich deposits in the Blackbird district are enclosed by strata-bound lenses composed mainly of Cl-rich Fe biotite; some deposits have quartz-rich envelopes.Whole-rock analyses of 48 Co- and/or Cu-rich samples show high concentrations of Au (up to 26.8 ppm), Bi (up to 9.16 wt %), Y (up to 0.83 wt %), ∑REEs (up to 2.56 wt %), Ni (up to 6,780 ppm), and Be (up to 1,180 ppm), with locally elevated U (up to 124 ppm) and Sn (up to 133 ppm); Zn and Pb contents are uniformly low (≤821 and ≤61 ppm, respectively). Varimax factor analysis of bulk compositions of these samples reveals geochemically distinct element groupings that reflect statistical associations of monazite, allanite, and xenotime; biotite and gold; detrital minerals; chalcopyrite and sparse stannite; quartz; and cobaltite with sparse selenides and tellurides. Significantly, Cu is statistically separate from Co and As

Ultrathin Au-Alloy Nanowires at the Liquid-Liquid Interface.

PubMed

Chatterjee, Dipanwita; Shetty, Shwetha; Müller-Caspary, Knut; Grieb, Tim; Krause, Florian F; Schowalter, Marco; Rosenauer, Andreas; Ravishankar, Narayanan

2018-03-14

Ultrathin bimetallic nanowires are of importance and interest for applications in electronic devices such as sensors and heterogeneous catalysts. In this work, we have designed a new, highly reproducible and generalized wet chemical method to synthesize uniform and monodispersed Au-based alloy (AuCu, AuPd, and AuPt) nanowires with tunable composition using microwave-assisted reduction at the liquid-liquid interface. These ultrathin alloy nanowires are below 4 nm in diameter and about 2 μm long. Detailed microstructural characterization shows that the wires have an face centred cubic (FCC) crystal structure, and they have low-energy twin-boundary and stacking-fault defects along the growth direction. The wires exhibit remarkable thermal and mechanical stability that is critical for important applications. The alloy wires exhibit excellent electrocatalytic activity for methanol oxidation in an alkaline medium.

The formation age of ores from the Pebble Cu-Au-Mo giant deposit (Alaska, United States)

NASA Astrophysics Data System (ADS)

Kremenetskii, A. A.; Popov, V. S.; Gromalova, N. A.

2012-02-01

Zircons from the porphyry-like quartz-diorite boss of the Pebble Cu-Au-Mo deposit (southwest Alaska) have been examined. By their appearance and internal structure (cathode luminescence and electron probing), the zircons have been subdivided into four genetic groups: (1) xenogenic detrital (mainly rounded); (2) magmatogene (protolith crystal in the center and growth zone at the edge); (3) hydrothermally altered (with new-formed regeneration edges in growth zones); (4) metamict-altered (unconsolidated center of the crystal and sectoring in growth zones). Based on SHRIMP U-Pb dating for the principal heterogeneous elements in every group, the following stages of ore formation have been identified for the Pebble deposit: (a) crystallization of quartz diorite-porphyry bosses (95-92 Ma, the concordant age is 94.7 ± 1.5 Ma); (b) late magmatic metasomatic alterations with copper-molybdenum mineralization (92-85 Ma, the concordant age is 90.15 ± 0.78 Ma); (c) postmagmatic argillization with epithermal gold-sulfide mineralization (82-80 Ma, the concordant age is 82.9 ± 2.7 Ma).

Fabrication and stability investigation of ultra-thin transparent and flexible Cu-Ag-Au tri-layer film on PET

NASA Astrophysics Data System (ADS)

Prakasarao, Ch Surya; D'souza, Slavia Deeksha; Hazarika, Pratim; Karthiselva N., S.; Ramesh Babu, R.; Kovendhan, M.; Kumar, R. Arockia; Joseph, D. Paul

2018-04-01

The need for transparent conducting electrodes with high transmittance, low sheet resistance and flexibility to replace Indium Tin Oxide is ever growing. We have deposited and studied the performance of ultra-thin Cu-Ag-Au tri-layer films over a flexible poly-ethylene terephthalate substrate. Scotch tape test showed good adhesion of the metallic film. Transmittance of the tri-layer was around 40 % in visible region. Optical profiler measurements were done to study the surface features. The XRD pattern revealed that film was amorphous. Sheet resistance measured by four probe technique was around 7.7 Ohm/Δ and was stable up to 423 K. The transport parameters by Hall effect showed high conductivity and carrier concentration with a mobility of 5.58 cm2/Vs. Tests performed in an indigenously designed bending unit indicated the films to be stable both mechanically and electrically even after 50,000 bending cycles.

Age of the granitic magmatism and the W-Mo mineralization in skarns of the Seridó belt (NE Brazil) based on zircon U-Pb (SHRIMP) and molybdenite Re-Os dating

NASA Astrophysics Data System (ADS)

Hollanda, Maria Helena B. M. de; Souza Neto, João A.; Archanjo, Carlos J.; Stein, Holly; Maia, Ana C. S.

2017-11-01

Over five hundred W-Mo skarns have been reported in the Neoproterozoic Seridó belt in the northeastern Brazil. The origin of these mineralizations has been attributed to metasomatic reactions occuring after the infiltration of hydrothermal fluids that are mostly derived from the plutonic magmatic activity that ranged between approximately 600 and 525 Ma. Here we date molybdenite using N-TIMS on Re-Os analysis of three major scheelite deposits (Brejuí, Bonfim and Bodó) hosted in the skarn horizons of the metasedimentary sequence. Molybdenite is an integral part of the mineralizations that include scheelite in skarns and, in the Bonfim deposit, gold concentrate in late brittle faults. The Re-Os ages are 554 ± 2 Ma (Brejuí), 524 ± 2 Ma (Bonfim) and 510 ± 2 Ma (Bodó). The age of the Brejuí molybdenite, however, appears to be anomalous based on the local geology of the deposit, which is located next to the contact of a batholith dated ca. 575 Ma. In turn, the Bonfim molybdenite yields similar ages in replicated samples with variable high Re contents. New U-Pb SHRIMP ages of four biotite (leuco)granite plutons vary from 577 ± 5 Ma to 526 ± 8 Ma, which overlap with molybdenite crystallization. These results indicate a close connection between the W-Mo mineralizations and the plutonic activity that intruded the belt after the peak HT/LP metamorphism. The latest pulses of felsic magmatism, which were contemporaneous with the emplacement of Be-Ta-Nb-Li pegmatites, therefore constitute a potential guide in the Seridó belt for prospective W-Mo deposits.

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.

Poly (vinyl alcohol)/gum karaya electrospun plasma treated membrane for the removal of nanoparticles (Au, Ag, Pt, CuO and Fe3O4) from aqueous solutions.

PubMed

Padil, Vinod Vellora Thekkae; Černík, Miroslav

2015-04-28

In the present work, nanofibre membranes composed of polyvinyl alcohol (PVA) and a natural gum karaya (GK) hydrocolloid were prepared using electrospinning. The electrospun membranes of PVA/GK were cross-linked with heat treatment and later methane plasma was used to obtain a hydrophobic membrane. The morphology, characterization and adsorption ability of P-NFM was assessed using scanning electron microscopy, UV-vis spectroscopy, ATR-FTIR techniques, water contact angle and ICP-MS analytical methods. The membrane was employed for the extraction of nanoparticles (Ag, Au, Pt, CuO and Fe3O4) from water. The nanoparticle extraction kinetic and adsorption isotherm perform the pseudo-second-order model and Langmuir isotherm model, respectively. The adsorption capacities of the membrane for the removal of NPs from water diverge in the order Pt>Au>Ag>CuO>Fe3O4. The high adsorption efficiency for the removal of NPs from water was compared with an untreated membrane. Physisorption, functional group interactions, complexation reactions between metal/metal oxide nanoparticles with various functional groups present in NFM and modified surface properties such as the balance of hydrophilicity/hydrophobicity, surface free energy, and the high surface area of the plasma treated membrane were possible mechanisms of NPs adsorption onto NFM. The regeneration and reusability were tested in five consecutive adsorption/desorption cycles. Copyright © 2015 Elsevier B.V. All rights reserved.

Adolescents' Expectations for Higher Education in Bogota, Colombia, and La Paz, Bolivia

ERIC Educational Resources Information Center

Forste, Renata; Heaton, Tim B.; Haas, David W.

2004-01-01

Drawing on status attainment models, the authors examine the effects of family, peer, and school factors on expectations to graduate from a university for a sample of high school students in Bogota, Colombia, and La Paz, Bolivia. The expansion of higher education in these countries has followed different strategies. In Bolivia, the policy has been…

The municipal solid waste management of La Paz (Bolivia): Challenges and opportunities for a sustainable development.

PubMed

Ferronato, Navarro; Gorritty Portillo, Marcelo Antonio; Guisbert Lizarazu, Edith Gabriela; Torretta, Vincenzo; Bezzi, Marco; Ragazzi, Marco

2018-03-01

Municipal solid waste management (MSWM) is considered an important public health, economic and environmental concern, especially in developing countries. This paper introduces the situation of MSWM in La Paz (Bolivia) in 2016, and is based on the Wasteaware indicators and waste flow analysis, useful tools for classifying and comparing waste treatment and management plans among other countries. Taking into account the lack of technology in waste treatment and the presence of a developed informal sector, the paper analyses the main strengths and weak points for implementing a sustainable MSWM. The research conducted revealed that the MSWM of La Paz is not efficient with regard to collection, recycling (8%), financial sustainability, and equity of the service. At the same time, local Government and stakeholders are interested in implementing new MSWM methods for improving the current sanitary state of the city and many efforts were made over the last ten years. In general terms, La Paz could be considered as a good study area for developing plans for waste valorization, becoming an example for a low-middle income developing big city of Latin America. The study provided a few considerations about the affordability of the methodology applied and critically analyzed the case study proposed.

3D inversion of SPECTREM and ZTEM airborne electromagnetic data from the Pebble Cu-Au-Mo porphyry deposit, Alaska

NASA Astrophysics Data System (ADS)

Pare, Pascal; Gribenko, Alexander V.; Cox, Leif H.; Čuma, Martin; Wilson, Glenn A.; Zhdanov, Michael S.; Legault, Jean; Smit, Jaco; Polome, Louis

2012-04-01

Geological, geochemical, and geophysical surveys have been conducted in the area of the Pebble Cu-Au-Mo porphyry deposit in south-west Alaska since 1985. This case study compares three-dimensional (3D) inversion results from Anglo American's proprietary SPECTREM 2000 fixed-wing time-domain airborne electromagnetic (AEM) and Geotech's ZTEM airborne audio-frequency magnetics (AFMAG) systems flown over the Pebble deposit. Within the commonality of their physics, 3D inversions of both SPECTREM and ZTEM recover conductivity models consistent with each other and the known geology. Both 3D inversions recover conductors coincident with alteration associated with both Pebble East and Pebble West. The high grade CuEqn 0.6% ore shell is not consistently following the high conductive trend, suggesting that the SPECTREM and ZTEM responses correspond in part to the sulphide distribution, but not directly with the ore mineralization. As in any exploration project, interpretation of both surveys has yielded an improved understanding of the geology, alteration and mineralization of the Pebble system and this will serve well for on-going exploration activities. There are distinct practical advantages to the use of both SPECTREM and ZTEM, so we draw no recommendation for either system. We can conclude however, that 3D inversion of both AEM and ZTEM surveys is now a practical consideration and that it has added value to exploration at Pebble.

Transformative Peace Education with Teachers: Lessons from "Juegos De Paz" in Rural Colombia

ERIC Educational Resources Information Center

Diazgranados, Silvia; Noonan, James; Brion-Meisels, Steven; Saldarriaga, Lina; Daza, Berta C.; Chávez, Minerva; Antonellis, Irene

2014-01-01

Effective peace education helps to create a transformation in the knowledge, skills, dispositions, and relationships of its students. Drawing on their experiences training teachers as part of "Juegos de Paz," an education for peace program that received support from the Colombian National Program for Citizenship Competencies, the authors…

Gold nanoclusters-Cu(2+) ensemble-based fluorescence turn-on and real-time assay for acetylcholinesterase activity and inhibitor screening.

PubMed

Sun, Jian; Yang, Xiurong

2015-12-15

Based on the specific binding of Cu(2+) ions to the 11-mercaptoundecanoic acid (11-MUA)-protected AuNCs with intense orange-red emission, we have proposed and constructed a novel fluorescent nanomaterials-metal ions ensemble at a nonfluorescence off-state. Subsequently, an AuNCs@11-MUA-Cu(2+) ensemble-based fluorescent chemosensor, which is amenable to convenient, sensitive, selective, turn-on and real-time assay of acetylcholinesterase (AChE), could be developed by using acetylthiocholine (ATCh) as the substrate. Herein, the sensing ensemble solution exhibits a marvelous fluorescent enhancement in the presence of AChE and ATCh, where AChE hydrolyzes its active substrate ATCh into thiocholine (TCh), and then TCh captures Cu(2+) from the ensemble, accompanied by the conversion from fluorescence off-state to on-state of the AuNCs. The AChE activity could be detected less than 0.05 mU/mL within a good linear range from 0.05 to 2.5 mU/mL. Our proposed fluorescence assay can be utilized to evaluate the AChE activity quantitatively in real biological sample, and furthermore to screen the inhibitor of AChE. As far as we know, the present study has reported the first analytical proposal for sensing AChE activity in real time by using a fluorescent nanomaterials-Cu(2+) ensemble or focusing on the Cu(2+)-triggered fluorescence quenching/recovery. This strategy paves a new avenue for exploring the biosensing applications of fluorescent AuNCs, and presents the prospect of AuNCs@11-MUA-Cu(2+) ensemble as versatile enzyme activity assay platforms by means of other appropriate substrates/analytes. Copyright © 2015 Elsevier B.V. All rights reserved.

Petrogenesis of the late Early Cretaceous granodiorite - Quartz diorite from eastern Guangdong, SE China: Implications for tectono-magmatic evolution and porphyry Cu-Au-Mo mineralization

NASA Astrophysics Data System (ADS)

Jia, Lihui; Mao, Jingwen; Liu, Peng; Li, Yang

2018-04-01

Comprehensive petrological, zircon U-Pb dating, Hf-O isotopes, whole rock geochemistry and Sr-Nd isotopes data are presented for the Xinwei and Sanrao intrusions in the eastern Guangdong Province, Southeast (SE) China, with an aim to constrain the petrogenesis, tectono-magmatic evolution and evaluate the implication for porphyry Cu-Au-Mo mineralization. The Xinwei intrusion is composed of granodiorite and quartz diorite, whilst the Sanrao intrusion consists of granodiorite. Zircon U-Pb ages show that both intrusions were emplaced at ca. 106-102 Ma. All rocks are metaluminous to weakly peraluminous, high-K calc-alkaline in composition, and they are characterized by LREEs enrichment, depletion in Nb, Ta, P, and Ti, and strongly fractionated LREEs to HREEs. The initial 87Sr/86Sr ratios range from 0.7055 to 0.7059, and εNd(t) values range from -3.9 to -3.0. Together with the relatively high εHf(t) values (-3.2 to 3.3) and low δ18O values (4.9‰ to 6.6‰), these data suggest that the Xinwei and Sanrao intrusions were derived from a mixed source: including the mantle-derived mafic magmas and lower continental crustal magmas. Fractional crystallization played an important role in the magmatic evolution of the Xinwei and Sanrao intrusions. The elemental and isotopic compositions of the Xinwei and Sanrao intrusions, as well as the high water content and oxidation state of their parental magmas, are similar to those of the ore-bearing granodiorites of the Luoboling porphyry Cu-Mo deposit in the Fujian Province, neighbouring east to the Guangdong Province, indicating that the late Early Cretaceous granodioritic intrusions in the eastern Guangdong Province may also have Cu-Au-Mo mineralization potential. The late Early Cretaceous magmatic event is firstly reported in eastern Guangdong, and represents a positive response of large-scale lithosphere extension and thinning, triggered by the changing subduction direction of the Paleo-Pacific plate from oblique subduction to

Zircon U-Pb and Hf-O isotopes trace the architecture of polymetallic deposits: A case study of the Jurassic ore-forming porphyries in the Qin-Hang metallogenic belt, China

NASA Astrophysics Data System (ADS)

Zhao, Panlao; Yuan, Shunda; Mao, Jingwen; Santosh, M.; Zhang, Dongliang

2017-11-01

The Qin-Hang intra-continental porphyry-skarn Cu polymetallic belt (QHMB) is among the economically important metallogenic belts in South China. The significant differences in the size and metal assemblage of the Jurassic magmatic-hydrothermal ore deposits in this belt remain as an enigma. Here we employ zircon U-Pb and Hf-O isotopes of the Tongshanling and Baoshan Cu-Pb-Zn deposits in the central part of the QHMB to investigate the contrasting metallogenic architecture. Our SIMS zircon U-Pb data indicate that the Tongshanling and Baoshan granodiorite formed at 160 Ma. These rocks show high Mg# values, and negative zircon εHf(t) and high δ18O values suggesting that the magmas of the granodiorite porphyries were mainly generated through the anatexis of older crustal components triggered by the input of mantle-derived magma. The minor content of amphibole phenocrysts, low Sr/Y ratios, negative Eu anomaly, and low zircon Ce4 +/Ce3 + ratios indicate that the porphyries are relatively less oxidized with less water content compared with the ore-bearing porphyries in the Dexing and Yuanzhuding porphyry Cu deposits in the northern and southern part of the QHMB, suggesting that high magmatic water content and oxidation state are important prerequisites for the formation of large size porphyry-skarn copper deposits in the QHMB. The positive correlation between zircon εHf(t) values with the Cu reserves, as well as zircon δ18O values with the Cu/(Cu + Pb + Zn) ratios of the deposits indicate that the magmatic sources exerted a first-order control on the volume and metal assemblage of deposits in the QHMB. The Hf and Nd isotope contour maps indicate that the central part of the QHMB has high potential for Pb-Zn-dominated magmatic-hydrothermal deposits, whereas the northern and southern part of the QHMB are prospective for large Cu deposits. Our results have important implications in formulating regional exploration strategies for Jurassic porphyry-skarn Cu-Pb-Zn deposits in

Mineral Deposit Data for Epigenetic Base- and Precious-metal and Uranium-thorium Deposits in South-central and Southwestern Montana and Southern and Central Idaho

USGS Publications Warehouse

Klein, T.L.

2004-01-01

Metal deposits spatially associated with the Cretaceous Boulder and Idaho batholiths of southwestern Montana and southern and central Idaho have been exploited since the early 1860s. Au was first discovered in placer deposits; exploitation of vein deposits in bedrock soon followed. In 1865, high-grade Ag vein deposits were discovered and remained economically important until the 1890s. Early high-grade deposits of Au, Ag and Pb were found in the weathered portions of the veins systems. As mining progressed to deeper levels, Ag and Pb grades diminished. Exploration for and development of these vein deposits in this area have continued until the present. A majority of these base- and precious-metal vein deposits are classified as polymetallic veins (PMV) and polymetallic carbonate-replacement (PMR) deposits in this compilation. Porphyry Cu and Mo, epithermal (Au, Ag, Hg and Sb), base- and precious-metal and W skarn, W vein, and U and Th vein deposits are also common in this area. The world-class Butte Cu porphyry and the Butte high-sulfidation Cu vein deposits are in this study area. PMV and PMR deposits are the most numerous in the region and constitute about 85% of the deposit records compiled. Several types of syngenetic/diagenetic sulfide mineral deposits in rocks of the Belt Supergroup or their equivalents are common in the region and they have been the source of a substantial metal production over the last century. These syngenetic deposits and their metamorphosed/structurally remobilized equivalents were not included in this database; therefore, deposits in the Idaho portion of the Coeur d'Alene district and the Idaho Cobalt belt, for example, have not been included because many of them are believed to be of this type.

Phosphate-binding pocket in Dicer-2 PAZ domain for high-fidelity siRNA production

PubMed Central

Kandasamy, Suresh K.

2016-01-01

The enzyme Dicer produces small silencing RNAs such as micro-RNAs (miRNAs) and small interfering RNAs (siRNAs). In Drosophila, Dicer-1 produces ∼22–24-nt miRNAs from pre-miRNAs, whereas Dicer-2 makes 21-nt siRNAs from long double-stranded RNAs (dsRNAs). How Dicer-2 precisely makes 21-nt siRNAs with a remarkably high fidelity is unknown. Here we report that recognition of the 5′-monophosphate of a long dsRNA substrate by a phosphate-binding pocket in the Dicer-2 PAZ (Piwi, Argonaute, and Zwille/Pinhead) domain is crucial for the length fidelity, but not the efficiency, in 21-nt siRNA production. Loss of the length fidelity, meaning increased length heterogeneity of siRNAs, caused by point mutations in the phosphate-binding pocket of the Dicer-2 PAZ domain decreased RNA silencing activity in vivo, showing the importance of the high fidelity to make 21-nt siRNAs. We propose that the 5′-monophosphate of a long dsRNA substrate is anchored by the phosphate-binding pocket in the Dicer-2 PAZ domain and the distance between the pocket and the RNA cleavage active site in the RNaseIII domain corresponds to the 21-nt pitch in the A-form duplex of a long dsRNA substrate, resulting in high-fidelity 21-nt siRNA production. This study sheds light on the molecular mechanism by which Dicer-2 produces 21-nt siRNAs with a remarkably high fidelity for efficient RNA silencing. PMID:27872309

The role of ophiolite in metallogeny of the Sikhote-Alin region

NASA Astrophysics Data System (ADS)

Kazachenko, V. T.; Perevoznikova, E. V.; Lavrik, S. N.; Skosareva, N. V.

2012-06-01

Metalliferous sediments of the Triassic siliceous formation of the Sikhote-Alin (manganese-silicate rocks and cherts with dispersed rhodochrosite, silicate-magnetite ores, and jasper) and skarns of the Dalnegorsk and Olginsk ore districts were initially the wash away products (Late Anisian-end of the Triassic) of the lateritic weathering crust on ophiolite in the islands. Manganese, iron, and other metals were deposited in the sediments of both lagoons (present-day, skarns) and island water areas (manganese-silicate and siliceousrhodochrosite rocks, silicate-magnetite ores, and jasper). Skarns contain boric and polymetallic ores thus indicating the occurrence of both shallow (periodically drying up) and quite deep (with hydrogen sulfide contamination zones) lagoons. Lead was deposited in protoliths of the skarn deposits in lagoons from the beginning of the Carboniferous to the beginning of the Late Anisian (initial island submergence). Tin, tin-leadzinc (with Ag), and silver-lead-zinc (with Sn and Au) vein deposits (Late Cretaceous-Paleogene) of the Taukha and Zhuravlevka Terrains contain lead deposited in the sediments flanking the islands of water areas with the hydrogen sulfide contamination zones, in the Carboniferous-Permian and Triassic metalliferous sediments.

Electronic Absorption and MCD Spectra for Pd(AuPPh(3))(8)(2+), Pt(AuPPh(3))(8)(2+), and Related Platinum-Centered Gold Cluster Complexes.

PubMed

Adrowski, Michael J.; Mason, W. Roy

1997-03-26

Electronic absorption and 7.0 T magnetic circular dichroism (MCD) spectra in the UV-vis region, 1.6 to approximately 4.0 &mgr;m(-)(1) (1 &mgr;m(-)(1) = 10(4) cm(-)(1)) are reported for [Pd(AuPPh(3))(8)](NO(3))(2) and [Pt(AuPPh(3))(8)](NO(3))(2) in acetonitrile solutions at room temperature. The MCD spectra are better resolved than the absorption spectra and consist of both A and B terms. The spectra are interpreted in terms of D(4)(d)() skeletal geometry and MO's that are approximated by 5s and 6s orbitals for Pd and Pt/Au atoms, respectively. The lowest energy excited configurations and states are attributed to intraframework (IF) Au(8)(2+) transitions. Evidence is also presented for Pt 5d --> Au 6s transitions in the MCD spectra for Pt(AuPPh(3))(8)(2+). Acetonitrile solution absorption and MCD spectra for the related Pt-centered cluster complexes [Pt(CO)(AuPPh(3))(8)](NO(3))(2), [Pt(AuP(p-tolyl)(3))(8)](NO(3))(2), [Pt(CuCl)(AuPPh(3))(8)](NO(3))(2), [Pt(AgNO(3))(AuPPh(3))(8)](NO(3))(2), [Pt(Hg)(2)(AuPPh(3))(8)](NO(3))(2), [Pt(HgCl)(2)(AuPPh(3))(8)](BF(4))(2), and [Pt(HgNO(3))(2)(AuPPh(3))(8)](BF(4))(2) are also reported and interpreted within the context of the model developed for the M(AuPPh(3))(8)(2+) complexes.

Geology, geochronology, and geochemistry of the Yinachang Fe-Cu-Au-REE deposit of the Kangdian region of SW China: Evidence for a Paleo-Mesoproterozoic tectono-magmatic event and associated IOCG systems in the western Yangtze Block

NASA Astrophysics Data System (ADS)

Hou, Lin; Ding, Jun; Deng, Jun; Peng, Hui-juan

2015-05-01

Numerous Fe-Cu-Au-rare earth element (REE) deposits have been identified within the Paleoproterozoic Dongchuan Group of the Kangdian region of SW China. This region hosts the Yinachang deposit, which contains more than 16.8 Mt Fe, 682.6 kt Cu, and significant amounts of Au and the REEs. Both the Haizi dolerite and a magmatic breccia in the central part of the Kangdian region are thought to be related to the Dongchuan dolerite in the northern part of this region; all three of these units provide evidence of the tectono-magmatic history of the Kunyang Rift and are closely spatially and temporally related to Fe-Cu-Au-REE mineralization in this region. Here, we present a new zircon U-Pb age for the Haizi dolerite (1764.7 ± 5.7 Ma), which is consistent with the known age of the Dongchuan dolerite (1765 ± 57 Ma), allowing the determination of the precise timing of Paleo-Mesoproterozoic intraplate mafic magmatism in this region (1.72-1.77 Ga). The breccia in this region formed during magmatism at around 1.73-1.74 Ga, as documented by zircon U-Pb dating of matrix material within the Yinachang magmatic breccia (1739 ± 13 Ma). The geochemistry of Haizi and Dongchuan dolerite samples provides evidence of intraplate extension in the Kangdian region, the majority of which was concentrated along the Kunyang Rift. The Kangdian region underwent variable degrees of extension, as evidenced by the fact that break-up in the central part of this region occurred earlier than in the north. This also led to the emplacement of deeper-sourced alkaline magmas (usually OIB-type magmas) in the central part of this region. The iron-oxide copper gold (IOCG) mineralization in the Kangdian region is associated with the upwelling of mantle material. A chalcopyrite Re-Os age of 1648 ± 14 Ma from the Yinachang Fe-Cu-Au-REE deposit obtained during this study is some 50-100 Myr younger than the timing of emplacement of the deeply sourced Haizi and Dongchuan dolerites. The Yinachang deposit is a

The spin-dependent electronic transport properties of M(dcdmp)2 (M = Cu, Au, Co, Ni) molecular devices based on zigzag graphene nanoribbon electrodes

NASA Astrophysics Data System (ADS)

Li, Dongde; Wu, Di; Zhang, Xiaojiao; Zeng, Bowen; Li, Mingjun; Duan, Haiming; Yang, Bingchu; Long, Mengqiu

2018-05-01

The spin-dependent electronic transport properties of M(dcdmp)2 (M = Cu, Au, Co, Ni; dcdmp = 2,3-dicyano-5,6-dimercaptopyrazyne) molecular devices based on zigzag graphene nanoribbon (ZGNR) electrodes were investigated by density functional theory combined nonequilibrium Green's function method (DFT-NEGF). Our results show that the spin-dependent transport properties of the M(dcdmp)2 molecular devices can be controlled by the spin configurations of the ZGNR electrodes, and the central 3d-transition metal atom can introduce a larger magnetism than that of the nonferrous metal one. Moreover, the perfect spin filtering effect, negative differential resistance, rectifying effect and magnetic resistance phenomena can be observed in our proposed M(dcdmp)2 molecular devices.

Uranium-series ages of marine terraces, La Paz Peninsula, Baja California Sur, Mexico

USGS Publications Warehouse

Sirkin, L.; Szabo, B. J.; Padilla, G.A.; Pedrin, S.A.; Diaz, E.R.

1990-01-01

Uranium-series dating of coral samples from raised marine terrace deposits between 1.5 and 10 m above sea level in the La Paz Peninsula area, Baja California Sur, yielded ages between 123 ka and 138 ka that are in agreement with previously reported results. The stratigraphy and ages of marine units near the El Coyote Arroyo indicate the presence of two high stands of the sea during the last interglacial or oxygen isotope substage 5e at about 140 ka and 123 ka. Accepting 5 m for the sea level during the last interglacial transgression, we calculate average uplift rates for the marine terraces of about ???70 mm/ka and 40 mm/ka. These slow rates of uplift indicate a relative stability of the La Paz peninsula area for the past 140 000 years. In contrast, areas of Baja California affected by major faultf experienced higher rates of uplift. Rockwell et al. (1987) reported vertical uplift rates of 180 to 300 mm/ka at Punta Banda within the Aqua Blanea fault zone in northern Baja California. ?? 1990 Springer-Verlag.

The chemistry of the superheavy elements. II. The stability of high oxidation states in group 11 elements: Relativistic coupled cluster calculations for the di-, tetra- and hexafluoro metallates of Cu, Ag, Au, and element 111

NASA Astrophysics Data System (ADS)

Seth, Michael; Cooke, Fiona; Schwerdtfeger, Peter; Heully, Jean-Louis; Pelissier, Michel

1998-09-01

The stability of the high oxidation states +3 and +5 in Group 11 fluorides is studied by relativistic Møller-Plesset (MP) and coupled cluster methods. Higher metal oxidation states are stabilized by relativistic effects. As a result, the hexafluoro complex of the Group 11 element with nuclear charge 111 and oxidation state +5 is the most stable compared to the other congeners. The results also suggest that AgF6- is thermodynamically stable and, therefore, it might be feasable to synthesize this compound. For the copper fluorides we observe very large oscillations in the Møller-Plesset series up to the fourth order. Nonrelativistic calculations lead to the expected trend in the metal-fluorine bond distances for the MF2- compounds, CuF2-AuF2-<(111)F2-. However, relativistic effects change this trend to CuF2-<AuF2-<(111)F2-

Au-Pt-Au nanoraspberry structures used for mercury ion detection

NASA Astrophysics Data System (ADS)

Huang, Jiang-Hao; Huang, Shuai; Wen, Xiaoyan; Li, Min; Lu, Haifei

2017-12-01

Detection of Hg2+ with high sensitivity is of great significance in the biochemical sensing field. Quantitative of Hg2+ was realized based on the influence of Hg2+ on the UV-vis absorption performance of Au-Pt-Au core-shell nanoraspberry (APA)-rhodamine-6G (R6G) structure. First, APA sol was added into R6G indicator solution and the UV-vis absorption signal intensity of R6G was evidently promoted. The signal intensity monotonously increased as more APA sol was added. However, when HgCl2 solution was introduced, the signal intensity declined. A linear relationship between Hg2+ concentration and signal intensity at 527 nm was revealed, based on which quantitative determination of Hg2+ could be realized. Hg2+ detection sensitivity was measured to be 0.031 a.u./M with a limit of detection of 10-7 M and the response time was 20 s. A high Hg2+ detection selectivity over Cu2+, Na+, Li+, and K+ was demonstrated. Due to its simplicity and high sensitivity, the proposed method could find an extensive application prospect in the Hg2+ detection field.

Ab initio molecular dynamics calculations on scattering of hyperthermal H atoms from Cu(111) and Au(111).

PubMed

Kroes, Geert-Jan; Pavanello, Michele; Blanco-Rey, María; Alducin, Maite; Auerbach, Daniel J

2014-08-07

Energy loss from the translational motion of an atom or molecule impinging on a metal surface to the surface may determine whether the incident particle can trap on the surface, and whether it has enough energy left to react with another molecule present at the surface. Although this is relevant to heterogeneous catalysis, the relative extent to which energy loss of hot atoms takes place to phonons or electron-hole pair (ehp) excitation, and its dependence on the system's parameters, remain largely unknown. We address these questions for two systems that present an extreme case of the mass ratio of the incident atom to the surface atom, i.e., H + Cu(111) and H + Au(111), by presenting adiabatic ab initio molecular dynamics (AIMD) predictions of the energy loss and angular distributions for an incidence energy of 5 eV. The results are compared to the results of AIMDEFp calculations modeling energy loss to ehp excitation using an electronic friction ("EF") model applied to the AIMD trajectories, so that the energy loss to the electrons is calculated "post" ("p") the computation of the AIMD trajectory. The AIMD calculations predict average energy losses of 0.38 eV for Cu(111) and 0.13-0.14 eV for Au(111) for H-atoms that scatter from these surfaces without penetrating the surface. These energies closely correspond with energy losses predicted with Baule models, which is suggestive of structure scattering. The predicted adiabatic integral energy loss spectra (integrated over all final scattering angles) all display a lowest energy peak at an energy corresponding to approximately 80% of the average adiabatic energy loss for non-penetrative scattering. In the adiabatic limit, this suggests a way of determining the approximate average energy loss of non-penetratively scattered H-atoms from the integral energy loss spectrum of all scattered H-atoms. The AIMDEFp calculations predict that in each case the lowest energy loss peak should show additional energy loss in the

Ab initio molecular dynamics calculations on scattering of hyperthermal H atoms from Cu(111) and Au(111)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroes, Geert-Jan, E-mail: g.j.kroes@chem.leidenuniv.nl; Pavanello, Michele; Blanco-Rey, María

2014-08-07

Energy loss from the translational motion of an atom or molecule impinging on a metal surface to the surface may determine whether the incident particle can trap on the surface, and whether it has enough energy left to react with another molecule present at the surface. Although this is relevant to heterogeneous catalysis, the relative extent to which energy loss of hot atoms takes place to phonons or electron-hole pair (ehp) excitation, and its dependence on the system's parameters, remain largely unknown. We address these questions for two systems that present an extreme case of the mass ratio of themore » incident atom to the surface atom, i.e., H + Cu(111) and H + Au(111), by presenting adiabatic ab initio molecular dynamics (AIMD) predictions of the energy loss and angular distributions for an incidence energy of 5 eV. The results are compared to the results of AIMDEFp calculations modeling energy loss to ehp excitation using an electronic friction (“EF”) model applied to the AIMD trajectories, so that the energy loss to the electrons is calculated “post” (“p”) the computation of the AIMD trajectory. The AIMD calculations predict average energy losses of 0.38 eV for Cu(111) and 0.13-0.14 eV for Au(111) for H-atoms that scatter from these surfaces without penetrating the surface. These energies closely correspond with energy losses predicted with Baule models, which is suggestive of structure scattering. The predicted adiabatic integral energy loss spectra (integrated over all final scattering angles) all display a lowest energy peak at an energy corresponding to approximately 80% of the average adiabatic energy loss for non-penetrative scattering. In the adiabatic limit, this suggests a way of determining the approximate average energy loss of non-penetratively scattered H-atoms from the integral energy loss spectrum of all scattered H-atoms. The AIMDEFp calculations predict that in each case the lowest energy loss peak should show additional

Modern carbonate sediments and environments of the LaPaz region, Baja California Sur, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halfar, J.; Ingle, J.C. Jr.; Cruz-Orozco, R.

1996-12-31

The Gulf of California represents one of the most productive and unique marginal seas in the world. The mouth of the Gulf captures warm equatorial water while annual wind patterns assure major upwelling of nutrient-rich water leading to a rich marine biota. These conditions have created a wide array of tropical through warm temperate carbonate environments. The most unusual of these environments is located in the La Paz region of Baja California Sur where tropical-subtropical water temperatures and low rainfall have allowed growth of corals, calcareous red algae, and other shelled invertebrates to form a carbonate bank environment. Sampling andmore » mapping transacts in shallow bays north of La Paz and on the adjacent Espiritu Santo island have revealed a full spectrum of subenvironments including mangrove bordered, terrigenous mud dominated coastal zones, which grade into carbonate tidal flats. In addition, single coral heads as well as incipient reef structures constructed by Porites and Pocillopora coral are present in deeper water areas. Coralline red algae, which are increasingly utilized for paleoenvironmental reconstructions, grow in high abundance on coral debris and in soft sediments and turn out to be main contributors to the La Paz carbonates. Analysis of siliciclastic admixtures, grain size and organic carbon content allow a classification of distinct environments. These data are supplemented by an evaluation of benthic foraminiferal zonations and the varying abundance of biogenic constituents. This Baja California Sur carbonate environment holds special relevance for the interpretation of analogous Neogene and Paleogene paleoenvironments marking major paleoclimatic and paleoceanographic events along the Pacific Coast of North America.« less

Modern carbonate sediments and environments of the LaPaz region, Baja California Sur, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halfar, J.; Ingle, J.C. Jr.; Cruz-Orozco, R.

1996-01-01

The Gulf of California represents one of the most productive and unique marginal seas in the world. The mouth of the Gulf captures warm equatorial water while annual wind patterns assure major upwelling of nutrient-rich water leading to a rich marine biota. These conditions have created a wide array of tropical through warm temperate carbonate environments. The most unusual of these environments is located in the La Paz region of Baja California Sur where tropical-subtropical water temperatures and low rainfall have allowed growth of corals, calcareous red algae, and other shelled invertebrates to form a carbonate bank environment. Sampling andmore » mapping transacts in shallow bays north of La Paz and on the adjacent Espiritu Santo island have revealed a full spectrum of subenvironments including mangrove bordered, terrigenous mud dominated coastal zones, which grade into carbonate tidal flats. In addition, single coral heads as well as incipient reef structures constructed by Porites and Pocillopora coral are present in deeper water areas. Coralline red algae, which are increasingly utilized for paleoenvironmental reconstructions, grow in high abundance on coral debris and in soft sediments and turn out to be main contributors to the La Paz carbonates. Analysis of siliciclastic admixtures, grain size and organic carbon content allow a classification of distinct environments. These data are supplemented by an evaluation of benthic foraminiferal zonations and the varying abundance of biogenic constituents. This Baja California Sur carbonate environment holds special relevance for the interpretation of analogous Neogene and Paleogene paleoenvironments marking major paleoclimatic and paleoceanographic events along the Pacific Coast of North America.« less

Relative inactivity during the last 140,000 years of a portion of the La Paz fault, southern Baja California Sur, Mexico

USGS Publications Warehouse

Szabo, B. J.; Hausback, B.P.; Smith, Joe T.

1990-01-01

Uranium-series dating of corals overlying the undeformed Punta Coyote gravels indicates that the underlying La Paz fault zone has been relatively inactive in this part of the Baja California peninsula during the last 140,000 years, and possibly for a significantly longer period. However, Holocene seismic activities along extensions of the fault zone north of Cabo San Lucas suggest potential seismic hazards for the city of La Paz (population 200,000), which lies about 6 km from the fault. ?? 1990 Springer-Verlag New York Inc.

Cu-As Decoupling in Hydrothermal Systems: A Link Between Pyrite Chemistry and Fluid Composition

NASA Astrophysics Data System (ADS)

Reich, M.; Tardani, D.; Deditius, A.; Chryssoulis, S.; Wrage, J.; Sanchez-Alfaro, P.; Andrea, H.; Cinthia, J.

2016-12-01

Chemical zonations in pyrite have been recognized in most hydrothermal ore deposit types, showing in some cases marked oscillatory alternation of metals and metalloids in pyrite growth zones (e.g., of Cu-rich, As-(Au)-depleted zones and As-(Au)-rich, Cu-depleted zones). This decoupled geochemical behavior of Cu and As has been interpreted as a result of chemical changes in ore-forming fluids, although direct evidence connecting fluctuations in hydrothermal fluid composition with metal partitioning into pyrite growth zones is still lacking. Here we report a comprehensive trace element database of pyrite from an active hydrothermal system, the Tolhuaca Geothermal System (TGS) in southern Chile. We combined high-spatial resolution and X-ray mapping capabilities of electron microprobe analysis (EMPA) with low detection limits and depth-profiling capabilities of secondary-ion mass spectrometry (SIMS) in a suite of pyrite samples retrieved from a 1 km drill hole that crosses the argillic and propylitic alteration zones of the geothermal system. We show that the concentrations of precious metals (e.g., Au, Ag), metalloids (e.g., As, Sb, Se, Te), and base and heavy metals (e.g., Cu, Co, Ni, Pb) in pyrite at the TGS are significant. Among the elements analyzed, arsenic, Cu and Co are the most abundant with concentrations that vary from sub-ppm levels to a few wt. %. Pyrites from the deeper propylitic zone do not show significant zonation and high Cu-(Co)-As concentrations correlate with each other. In contrast, well-developed zonations were detected in pyrite from the shallow argillic alteration zone, where Cu(Co)-rich, As-depleted cores alternate with Cu(Co)-depleted, As-rich rims. These microanalytical data were contrasted with chemical data of fluid inclusion in quartz veins (high Cu/Na and low As/Na) and borehole fluids (low Cu/Na and high As/Na) reported at the TGS, showing a clear correspondence between Cu and As concentrations in pyrite-forming fluids and chemical

Geochemical constraints on the genesis of the Scheelite dome intrusion-related gold deposit, Tombstone gold belt, Yukon, Canada

USGS Publications Warehouse

Mair, J.L.; Goldfarb, R.J.; Johnson, C.A.; Hart, C.J.R.; Marsh, E.E.

2006-01-01

The Scheelite dome intrusion-related gold deposit, western Selwyn basin, Yukon, is hosted in hornfelsed metasedimentary strata that lie adjacent to the exposed apices of a monzogranite to quartz monzonite plutonic complex of the mid-Cretaceous Tombstone-Tungsten magmatic belt, Tintina gold province, Alaska and Yukon. A variety of mineralization styles occur throughout a 10- ?? 3-km east-trending corridor and include reduced Au- and W-rich skarns, Au, W- and Ag-Pb-Zn-Sb-rich quartz tension-vein arrays, and multiphase fault veins and isolated zones of Au-rich sericite-carbonate altered rock. Integrated U-Pb SHRIMP data for magmatic zircon and Ar-Ar data for magmatic and hydrotbermal biotite indicate that gold mineralization occurred within 1 to 2 m.y. of magma emplacement. Fluid inclusion, oxygen isotope, and arsenopyrite geothermometry data indicate that hydrothermal minerals formed at depths of 6 to 9 km over a temperature range from 550??C. High-temperature Au-rich skarns formed at >400??C, whereas vein-hosted mineralization formed at 280?? to 380??C. In skarns, Au is strongly associated with enrichments of Bi, Te, W, and As, whereas a variety of Au-rich veins occur, with Asrich (type 1), and Te- and W-rich (type 2) end members. Silver-Pb-Zn-Sb veins are typically Au poor and represent the latest and lowest temperature phase in the hydrothermal paragenesis. The fluid inclusion data indicate that all mineralization styles were formed from low-salinity (???4 wt % NaCl equiv) aqueous-carbonic fluids, consistent with the composition of fluid inclusions within infilled miarolitic cavities in the intrusive rocks. However, the nonaqueous fluid was predominantly CH4 in skarn, CO2 in Au-Te and Au-W veins, and a fluid with roughly equal amounts Of CO2, CH4, and N2 in Au-As and Ag-Pb-Zn-Sb veins. Oxygen isotope data are consistent with a mineralizing fluid of predominantly magmatic origin that was variably modified to more positive ??18O values during interaction with 18O

AuNx stabilization with interstitial nitrogen atoms: A Density Functional Theory Study

NASA Astrophysics Data System (ADS)

Quintero, J. H.; Gonzalez-Hernandez, R.; Ospina, R.; Mariño, A.

2017-06-01

Researchers have been studying 4d and 5d Series Transition Metal Nitrides lately as a result of the experimental production of AuN, PtN, CuN. In this paper, we used the Density Functional Theory (DFT) implementing a pseudopotential plane-wave method to study the incorporation of nitrogen atoms in the face-centered cube (fcc) lattice of gold (Au). First, we took the fcc structure of gold, and gradually located the nitrogen atoms in tetrahedral (TH) and octahedral (OH) interstitial sites. AuN stabilized in: 2OH (30%), 4OH and 4TH (50%), 4OH - 2TH (close to the wurtzite structure) and 6TH (60%). This leads us to think that AuN behaves like a Transition Metal Nitride since the nitrogen atoms look for tetrahedral sites.

Reaction of YBa2Cu3O(7-beta) with Gold, Silver, Bismuth and Lead: Substitution Chemistry and Composite Fabrication

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; Gaier, James R.

1993-01-01

The reaction of YBa2Cu3O(7-beta) with Au, Ag, Bi, and Ph ions or metal is described. Three types of materials were produced: a well-defined series of homogeneous superconductors was obtained for Au ion substitution with little effect on T(sub c); attempted Ag and Bi ion substitution resulted in multi-phase samples with slightly enhanced T(sub c); finally, attempts to produce superconducting metal/superconducting ceramic composites with Pb and Bi powders resulted in multi-phase samples with drastically diminished superconducting properties. For Au- substituted superconductors, YBa2(Cu(l-x)Au(x))3O(7-beta), a substitution series (x = 0 - 0.1) has been synthesized. For x = 0.1 there was no change in the a and b lattice parameters (a = 3.826 A and b = 3.889 A) but a 0.06 A c axis expansion to 11.75 A was observed. The valence of Cu and Au in YBa2Au(0.3)Cu(2.7)O(7-beta) was investigated using X-ray Absorption Near-Edge Structure (XANES). X-ray studies indicate that Au goes into the Cu(l) site and Cu K edge XANES shows that this has little effect on the oxidation state of the remaining copper. A small effect on T(sub c) is observed (T(sub c) = 89 K for x = 0.10). Ag and Bi addition results in a rise in T(sub c) and a decrease in (delta)T(sub c) at low levels (x = 0.10 Ag, T(sub c) = 94 K and (delta)T(sub c) = 0.5 K; x = 0.02 Bi, T(sub c) = 94 K and (delta)T(sub c) = 1K) relative to typical values for YBa2Cu3O(7-beta) (T(sub c) = 91 K, (delta)T(sub c) = 2 K). Attempts at fabrication of Pb- and Pb(1-x)Bi(x)-superconductor composites are described. Cold pressing followed by low temperature (200 C) sintering resulted in a composite which excluded flux below 90 K but did not show zero electrical resistance until the metal (alloy) superconducting transition. X-ray diffraction showed the presence of pervoskite and metal. Processing at moderate (450 C) or high (950 C) temperatures resulted in oxygen-depleted pervoskite and/or metal oxides. These materials displayed greatly

Pickup protons and pressure-balanced structures: Voyager 2 observations in merged interaction regions near 35 AU

NASA Astrophysics Data System (ADS)

Burlaga, L. F.; Ness, N. F.; Belcher, J. W.; Szabo, A.; Isenberg, P. A.; Lee, M. A.

1994-11-01

Five pressure-balanced structures, each with a scale of the order of a few hundredths of an astonomical unit (AU), were identified in two merged interaction regions (MIRs) near 35 AU in the Voyager 2 plasma and magnetic field data. They include a tangential discontinuity, simple and complex magnetic holes, slow correlated variations among the plasma and magnetic field parameters, and complex uncorrelated variations among the parameters. The changes in the magnetic pressure in these events are balanced by changes in the pressure of interstellar pickup protons. Thus the pickup protons probably play a major role in the dynamics of the MIRs. The solar wind proton and electron pressures are relatively unimportant in the MIRs at 35 AU and beyond. The region near 35 AU is transition region: the Sun is the source of the magnetic field, but the interstellar medium in source of pickups protons. Relative to the solar wind proton guyroadius, the thicknesses of the discontinuities and simple magnetic holes observed near 35 AU are at least an order of magnitude greater than those observed at 1 AU. However, the thicknesses of the tangential discontinuity and simple magnetic holes observed near 35 AU (in units of the pickup proton Larmor radius) are comparable to those observed at 1 AU (in units of the solar wind proton gyroradius). Thus the gyroradius of interstellar pickup protons controls the thickness of current sheets near 35 AU. We determine the interstellar pickup proton pressure in the PBSs. Using a model for the pickup proton temperature, we estimate that the average interstellar pickup proton pressure, temperature, and density in the MIRs at 35 AU are (0.53 +/- 0.14) x 10-12 erg/cu cm, (5.8 +/- 0.4) x 106 K and (7 +/- 2) x 10-4/cu cm.

Geologic setting and characteristic of mineral deposits in the central Wasatch Mountains, Utah

USGS Publications Warehouse

John, David A.

1997-01-01

Base- and precious-metal deposits in the central Wasatch Mountains southeast of Salt Lake City were mined for more than 100 years beginning in 1868. Deposits present in the Park City, Little Cottonwood, and Big Cottonwood mining districts include Ag-Pb-Zn ± Cu ± Au replacement and veins, a low-grade porphyry Cu-Au deposit, Cu-bearing skarns, a quartz monzonite-type (low F) porphyry Mo deposit, and high sulfidation (quartz-alunite) Au deposits. Most production came from polymetallic replacement and vein deposits in the Park City mining district, which has a recorded production of more than 1.4 million oz Au , 253 million oz Ag, 2.7 billion lbs Pb, 1.5 billion lbs Zn, and 129 million lbs Cu from 1872 to 1978. Production in the Little and Big Cottonwood districts, mostly from Pb-Ag replacement deposits, was much smaller. Most mineral deposits in the central Wasatch Mountains are genetically related to the Wasatch igneous belt, a series of high-K calc-alkaline stocks and cogenetic volcanic rocks that formed about 41(?) to 30 Ma. The mineral deposits mostly formed near the end of magmatic activity between about 36 to 31.4 Ma. A subeconomic porphyry Mo deposit in the Little Cottonwood stock is notably younger having formed about 26 to 23.5 Ma. The intrusive rocks were emplaced mostly along the westward extension of the west-trending Uinta arch during a period of NW-SE-directed extension, and much of the mineralization in the Park City district controlled by ENE-striking normal faults. About 15 degrees of eastward tilting of the central Wasatch Mountains during Late Cenozoic Basin and Range extension has resulted in progressively deeper levels of exposure from <1 km on the east to about 11 km on the west and in profound variations in the types of minerals deposits exposed in different parts of the range. Most deposits formed at paleodepths ≤5 km, and the most productive deposits in the Park City district formed at depths of 1 to 2 km. The prophyry Mo deposit in the

Surface effects on the mechanical elongation of AuCu nanowires: De-alloying and the formation of mixed suspended atomic chains

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lagos, M. J.; Laboratório Nacional de Nanotecnologia-LNNANO, 13083-970 Campinas-SP; Autreto, P. A. S.

2015-03-07

We report here an atomistic study of the mechanical deformation of Au{sub x}Cu{sub (1−x)} atomic-size wires (nanowires (NWs)) by means of high resolution transmission electron microscopy experiments. Molecular dynamics simulations were also carried out in order to obtain deeper insights on the dynamical properties of stretched NWs. The mechanical properties are significantly dependent on the chemical composition that evolves in time at the junction; some structures exhibit a remarkable de-alloying behavior. Also, our results represent the first experimental realization of mixed linear atomic chains (LACs) among transition and noble metals; in particular, surface energies induce chemical gradients on NW surfacesmore » that can be exploited to control the relative LAC compositions (different number of gold and copper atoms). The implications of these results for nanocatalysis and spin transport of one-atom-thick metal wires are addressed.« less

Effect of Gold Nanoparticles Addition to CuO–ZnO/A₂O₃ Catalyst in Conversion of Carbon Dioxide to Methanol.

PubMed

Kim, Ki-Joong; Ahn, Ho-Geun

2017-04-01

Hydrogenation of carbon dioxide (CO₂) into methanol (CH₃OH) was carried out in the CuO–ZnO based supported gold catalyst prepared by the co-precipitation method. When gold nanoparticles were added to the CuO–ZnO/Al2O₃ catalysts (CuO–ZnO/Au/Al₂O₃), the CO₂ conversion and CH₃OH yield were increased (two times higher than that of CuO–ZnO/Al₂O₃ catalyst) with increasing reaction pressure, but selectivity of CH3OH was decreased. The main reason of this result could suggest the importance gold-oxides interface in CH₃OH formation through hydrogenation of CO₂. Maximum selectivity and yield to CH₃OH over CuO–ZnO/Au/Al₂O₃ were obtained at 250°C and under 15–20 bars.

Fluid evolution of Au-Cu zones in Um Balad area, North Eastern Desert of Egypt: Implications from mineral chemistry and fluid inclusions

NASA Astrophysics Data System (ADS)

Abd El Monsef, Mohamed; Salem, Ibrahim; Slobodník, Marek; Ragab, Ahmed

2018-07-01

Scanning electron microscope (SEM), Electron microprobe (EMPA) and fluid inclusion studies of the ore body, as well as geochemical analyses of country rocks were performed to determine the nature and characteristics of the mineralizing fluid responsible for Au-Cu deposits in Um Balad area, Northern Eastern Desert of Egypt. The Um Balad Au-Cu deposits are confined to well developed-quartz veins and veinlets cutting through the hosting country rocks. Petrographic and geochemical investigations of the hosting rocks distinguished between two main rock units; 1) metagabbro-diorite rocks with tholeiitic nature derived in island arc/continental margin tectonic regime, and 2) granodiorite rocks formed from calc-alkaline magma in continental margin regime. Wallrock alterations are represented by propylitic and argillic types. The mineralized quartz veins are striking in NE-SW direction and dipping between (35°-45°) in SE direction, other mineralized mafic dykes enriched with auriferous quartz veinlets are trending NE-SW and dipping 70°/SE. The main ore minerals are represented by gold, chalcopyrite, pyrite, sphalerite, malachite, covellite and goethite. While, geffroyite, cuprite, chrysocolla, pseudomalachite, britholite, wolframite, scheelite, hematite and rutile are detected as minor constituents. Fluid inclusions microthermometry and isochore calculations combined with chlorite geothermometry revealed that the Um Balad deposits were formed at temperature ranging from 305 °C to 325 °C and pressure between (100-500 bar). The mineralization had been developed in the shallow levels, beneath the water table at depth of 350-1760 m, rather than common mesothermal vein-type deposits in Egypt. Magmatic water have been suggested as the main source for the mineralized fluid. The transportation of the gold metal seems to be happen as bisulfide complexes in moderately acidic environment. The deposition was resulted from combination of changes in physico-chemical parameters

Correlates of Adolescent Pregnancy in La Paz, Bolivia: Findings from a Quantitative-Qualitative Study.

ERIC Educational Resources Information Center

Lipovsek, Varja; Karim, Ali Mehryar; Gutierrez, Emily Zielinski; Magnani, Robert J.; Gomez, Maria del Carmen Castro

2002-01-01

Study explores why some female adolescents in La Paz, Bolivia, become pregnant while others in similar circumstances avoid early pregnancy. Results reveal that girls who had experienced a pregnancy were less likely to have reported affectionate and supportive parents, more likely to have reported fighting in their home, and exhibited lower levels…

Interaction between Diethyldithiocarbamate and Cu(II) on Gold in Non-Cyanide Wastewater

PubMed Central

Ly, Nguyễn Hoàng; Nguyen, Thanh Danh; Zoh, Kyung-Duk; Joo, Sang-Woo

2017-01-01

A surface-enhanced Raman scattering (SERS) detection method for environmental copper ions (Cu2+) was developed according to the vibrational spectral change of diethyldithiocarbamate (DDTC) on gold nanoparticles (AuNPs). The ultraviolet-visible (UV-Vis) absorption spectra indicated that DDTC formed a complex with Cu2+, showing a prominent peak at ~450 nm. We found Raman spectral changes in DDTC from ~1490 cm−1 to ~1504 cm−1 on AuNPs at a high concentration of Cu2+ above 1 μM. The other ions of Zn2+, Pb2+, Ni2+, NH4+, Mn2+, Mg2+, K+, Hg2+, Fe2+, Fe3+, Cr3+, Co2+, Cd2+, and Ca2+ did not produce such spectral changes, even after they reacted with DDTC. The electroplating industrial wastewater samples were tested under the interference of highly concentrated ions of Fe3+, Ni2+, and Zn2+. The Raman spectroscopy-based quantification of Cu2+ ions was able to be achieved for the wastewater after treatment with alkaline chlorination, whereas the cyanide-containing water did not show any spectral changes, due to the complexation of the cyanide with the Cu2+ ions. A micromolar range detection limit of Cu2+ ions could be achieved by analyzing the Raman spectra of DDTC in the cyanide-removed water. PMID:29140287

Interaction between Diethyldithiocarbamate and Cu(II) on Gold in Non-Cyanide Wastewater.

PubMed

Ly, Nguyễn Hoàng; Nguyen, Thanh Danh; Zoh, Kyung-Duk; Joo, Sang-Woo

2017-11-15

A surface-enhanced Raman scattering (SERS) detection method for environmental copper ions (Cu 2+ ) was developed according to the vibrational spectral change of diethyldithiocarbamate (DDTC) on gold nanoparticles (AuNPs). The ultraviolet-visible (UV-Vis) absorption spectra indicated that DDTC formed a complex with Cu 2+ , showing a prominent peak at ~450 nm. We found Raman spectral changes in DDTC from ~1490 cm -1 to ~1504 cm -1 on AuNPs at a high concentration of Cu 2+ above 1 μM. The other ions of Zn 2+ , Pb 2+ , Ni 2+ , NH₄⁺, Mn 2+ , Mg 2+ , K⁺, Hg 2+ , Fe 2+ , Fe 3+ , Cr 3+ , Co 2+ , Cd 2+ , and Ca 2+ did not produce such spectral changes, even after they reacted with DDTC. The electroplating industrial wastewater samples were tested under the interference of highly concentrated ions of Fe 3+ , Ni 2+ , and Zn 2+ . The Raman spectroscopy-based quantification of Cu 2+ ions was able to be achieved for the wastewater after treatment with alkaline chlorination, whereas the cyanide-containing water did not show any spectral changes, due to the complexation of the cyanide with the Cu 2+ ions. A micromolar range detection limit of Cu 2+ ions could be achieved by analyzing the Raman spectra of DDTC in the cyanide-removed water.

Undiscovered locatable mineral resources in the Bay Resource Management Plan Area, Southwestern Alaska: A probabilistic assessment

USGS Publications Warehouse

Schmidt, J.M.; Light, T.D.; Drew, L.J.; Wilson, Frederic H.; Miller, M.L.; Saltus, R.W.

2007-01-01

The Bay Resource Management Plan (RMP) area in southwestern Alaska, north and northeast of Bristol Bay contains significant potential for undiscovered locatable mineral resources of base and precious metals, in addition to metallic mineral deposits that are already known. A quantitative probabilistic assessment has identified 24 tracts of land that are permissive for 17 mineral deposit model types likely to be explored for within the next 15 years in this region. Commodities we discuss in this report that have potential to occur in the Bay RMP area are Ag, Au, Cr, Cu, Fe, Hg, Mo, Pb, Sn, W, Zn, and platinum-group elements. Geoscience data for the region are sufficient to make quantitative estimates of the number of undiscovered deposits only for porphyry copper, epithermal vein, copper skarn, iron skarn, hot-spring mercury, placer gold, and placer platinum-deposit models. A description of a group of shallow- to intermediate-level intrusion-related gold deposits is combined with grade and tonnage data from 13 deposits of this type to provide a quantitative estimate of undiscovered deposits of this new type. We estimate that significant resources of Ag, Au, Cu, Fe, Hg, Mo, Pb, and Pt occur in the Bay Resource Management Plan area in these deposit types. At the 10th percentile probability level, the Bay RMP area is estimated to contain 10,067 metric tons silver, 1,485 metric tons gold, 12.66 million metric tons copper, 560 million metric tons iron, 8,100 metric tons mercury, 500,000 metric tons molybdenum, 150 metric tons lead, and 17 metric tons of platinum in undiscovered deposits of the eight quantified deposit types. At the 90th percentile probability level, the Bay RMP area is estimated to contain 89 metric tons silver, 14 metric tons gold, 911,215 metric tons copper, 330,000 metric tons iron, 1 metric ton mercury, 8,600 metric tons molybdenum and 1 metric ton platinum in undiscovered deposits of the eight deposit types. Other commodities, which may occur in the

Carboniferous-Permian tectonic transition envisaged in two magmatic episodes at the Kuruer Cu-Au deposit, Western Tianshan (NW China)

NASA Astrophysics Data System (ADS)

Yu, Jie; Li, Nuo; Qi, Nan; Guo, Jian-Ping; Chen, Yan-Jing

2018-03-01

The Western Tianshan in NW China is one of the most important gold provinces in the Central Asian Orogenic Belt (CAOB). The recently discovered Kuruer Cu-Au deposit has been interpreted to represent a transition from high-sulfidation epithermal to porphyry mineralization system. In this study, we present new LA-ICP-MS zircon U-Pb ages for the many magmatic rock types at Kuruer, including the Dahalajunshan Formation andesitic tuff (333.2 ± 1.6 Ma), diorite porphyry (269.7 ± 2.0 Ma), slightly-altered (264.4 ± 2.6 Ma) and intensively-altered (270.5 ± 2.5 Ma) albite porphyry. These ages reveal two distinct magmatic episodes: The Early Carboniferous Dahalajunshan Formation (wall rocks) andesitic tuff samples contain narrow ranges of SiO2 (60.29-61.28 wt.%), TiO2 (0.96-0.98 wt.%), Al2O3 (16.55-16.57 wt.%) and Fe2O3T (5.36-5.57 wt.%). The tuff is characterized by LREE enrichment and HFSE depletion, as well as LREE/HREE enrichment ((La/Yb)N = 8.31-8.76) and negative Eu anomalies (δEu = 0.64-0.76). Zircon εHf (t) values are 5.4-8.2, and two-stage Hf model ages (TDM2) are 821-1016 Ma, indicating partial melting of a moderately depleted mantle wedge with Precambrian continental crustal input. The ore-forming Middle Permian diorite porphyry and (quartz) albite porphyry have variable major oxide compositions (e.g., SiO2 = 53.09-53.12 wt.% for the diorite porphyry, 70.84-78.03 wt.% for the albite porphyry, and 74.07-75.03 wt.% for the quartz albite porphyry) but similar chondrite-normalized REE and primitive mantle-normalized multi-element patterns. These porphyries display LREE enrichment and HFSE depletion, as well as elevated LREE/HREE enrichment and negative Eu anomalies. The positive zircon εHf(t) values (11.7-15.9 for the diorite porphyry, 8.9-14.9 for the albite porphyry) and young two-stage Hf model ages (TDM2) (282-542 Ma for the diorite porphyry, 337-717 Ma for the albite porphyry) indicate a major juvenile continental crustal involvement. We propose that the

First principles absorption spectra of Cu{sub n} (n = 2 - 20) clusters.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baishya, K.; Idrobo, J. C.; Ogut, S.

2011-06-17

Optical absorption spectra for the computed ground state structures of copper clusters (Cu{sub n}, n = 2-20) are investigated from first principles using time-dependent density functional theory in the adiabatic local density approximation (TDLDA). The results are compared with available experimental data, existing calculations, and with results from our previous computations on silver and gold clusters. The main effects of d electrons on the absorption spectra, quenching the oscillator strengths, and getting directly involved in low-energy excitations increase in going from Ag{sub n} to Au{sub n} to Cu{sub n} due to the increase in the hybridization of the occupied, yetmore » shallow, d orbitals and the partially occupied s orbitals. We predict that while Cu nanoparticles of spherical or moderately ellipsoidal shape do not exhibit Mie (surface plasmon) resonances, unlike the case for Ag and Au, extremely prolate or oblate Cu nanoparticles with eccentricities near unity should give rise to Mie resonances in the lower end of the visible range and in the infrared. This tunable resonance predicted by the classical Mie-Gans theory is reproduced with remarkable accuracy by our TDLDA computations on hypothetical Cu clusters in the form of zigzag chains with as few as 6 to 20 atoms.« less

Surface chirality of CuO thin films.

PubMed

Widmer, Roland; Haug, Franz-Josef; Ruffieux, Pascal; Gröning, Oliver; Bielmann, Michael; Gröning, Pierangelo; Fasel, Roman

2006-11-01

We present X-ray photoelectron spectroscopy (XPS) and X-ray photoelectron diffraction (XPD) investigations of CuO thin films electrochemically deposited on an Au(001) single-crystal surface from a solution containing chiral tartaric acid (TA). The presence of enantiopure TA in the deposition process results in a homochiral CuO surface, as revealed by XPD. On the other hand, XPD patterns of films deposited with racemic tartaric acid or the "achiral" meso-tartaric acid are completely symmetric. A detailed analysis of the experimental data using single scattering cluster calculations reveals that the films grown with l(+)-TA exhibit a CuO(1) orientation, whereas growth in the presence of d(-)-TA results in a CuO(11) surface orientation. A simple bulk-truncated model structure with two terminating oxygen layers reproduces the experimental XPD data. Deposition with alternating enantiomers of tartaric acid leads to CuO films of alternating chirality. Enantiospecifity of the chiral CuO surfaces is demonstrated by further deposition of CuO from a solution containing racemic tartaric acid. The pre-deposited homochiral films exhibit selectivity toward the same enantiomeric deposition pathway.

Relativity-Induced Bonding Pattern Change in Coinage Metal Dimers M2 (M = Cu, Ag, Au, Rg).

PubMed

Li, Wan-Lu; Lu, Jun-Bo; Wang, Zhen-Ling; Hu, Han-Shi; Li, Jun

2018-05-07

The periodic table provides a fundamental protocol for qualitatively classifying and predicting chemical properties based on periodicity. While the periodic law of chemical elements had already been rationalized within the framework of the nonrelativistic description of chemistry with quantum mechanics, this law was later known to be affected significantly by relativity. We here report a systematic theoretical study on the chemical bonding pattern change in the coinage metal dimers (Cu 2 , Ag 2 , Au 2 , Rg 2 ) due to the relativistic effect on the superheavy elements. Unlike the lighter congeners basically demonstrating ns- ns bonding character and a 0 g + ground state, Rg 2 shows unique 6d-6d bonding induced by strong relativity. Because of relativistic spin-orbit (SO) coupling effect in Rg 2 , two nearly degenerate SO states, 0 g + and 2 u , exist as candidate of the ground state. This relativity-induced change of bonding mechanism gives rise to various unique alteration of chemical properties compared with the lighter dimers, including higher intrinsic bond energy, force constant, and nuclear shielding. Our work thus provides a rather simple but clear-cut example, where the chemical bonding picture is significantly changed by relativistic effect, demonstrating the modified periodic law in heavy-element chemistry.

Mesozoic Magmatism and Base-Metal Mineralization in the Fortymile Mining District, Eastern Alaska - Initial Results of Petrographic, Geochemical, and Isotopic Studies in the Mount Veta Area

USGS Publications Warehouse

Dusel-Bacon, Cynthia; Slack, John F.; Aleinikoff, John N.; Mortensen, James K.

2009-01-01

-bearing Zn skarn. Cu-Zn-Pb-Ag-Au showings at the Oscar pros-pect occur in marble-hosted magnetite and pyrrhotite skarn that is spatially related to the stocks, dikes, and sills of the Early Jurassic syenite of Mount Veta. Mineralized rocks at the Eva Creek Ag-Zn-Pb-Cu prospect are within 1.5 km of the Mount Veta pluton, which is epidotized and locally altered along its contact with metamorphosed country rock east of the prospect. We report five new sulfide Pb-isotopic analyses from the LWM, Oscar, and Eva Creek prospects and compare these sulfide Pb-isotopic ratios with those for sulfides from nearby deposits and prospects in the Yukon-Tanana Upland and with feldspar Pb-isotopic ratios for Mesozoic plutons in the region. Disparities between the Pb-isotopic ratios for sulfides and igneous feldspars are consistent with a carbonate-replacement model for both the LWM and Eva Creek prospects. The presence in the Fortymile district of base-metal sulfides within both calc-silicate-rich skarns and the calc-silicate-free carbonate replacement deposits may reflect multistage mineralization by magmatic-hydrothermal systems during the emplacement of two or more magmatically unrelated igneous intrusions. Alternatively, all of the mineralized occurrences could be products of one regionally zoned system that formed during the intrusion of a single pluton. In addition to the likely origin of some of the base-metal occurrences by intrusion-related hydrothermal fluids, proximity of the LWM prospect to the northeast-striking, high-angle Kechumstuk Fault suggests that fluid flow along the fault also played an important role during carbonate-replacement mineralization.

Resonance-enhanced electron-impact excitation of Cu-like gold

NASA Astrophysics Data System (ADS)

Xia, L.; Zhang, C. Y.; Si, R.; Guo, X. L.; Chen, Z. B.; Yan, J.; Li, S.; Chen, C. Y.; Wang, K.

2017-09-01

Employing the independent-process and isolated-resonance approximations using distorted-waves (IPIRDW), we have performed a series of calculations of the resonance-enhanced electron-impact excitations (EIE) among 27 singly excited levels from the n ≤ 6 configurations of Cu-like gold (Au, Z = 79). Resonance excitation (RE) contributions from both the n = 4 → 4 - 7 and n = 3 → 4 core excitations have been considered. Our results demonstrate that RE contributions are significant and enhance the effective collision strengths (ϒ) of certain excitations by up to an order of magnitude at low temperature (106.1 K), and are still important at relatively high temperature (107.5 K). Results from test calculations of the resonance-enhanced EIE processes among 16 levels from the n ≤ 5 configurations using both the Dirac R-matrix (DRM) and IPIRDW approaches agree very well with each other. This means that the close-coupling effects are not important for this ion, and thus warrants the reliability of present resonance-enhanced EIE data among the 27 levels. The results from the collisional-radiative model (CRM) show that, at 3000 eV, near where Cu-like Au is most abundant, RE contributions have important effects (up to 25%) on the density diagnostic line intensity ratios, which are sensitive near 1020 cm-3. The present work is the first EIE research including RE contributions for Cu-like Au. Our EIE data are more accurate than previous results due to our consideration of RE contributions, and the data should be helpful for modeling and diagnosing a variety of plasmas.

A GREEN CHEMISTRY APPROACH TO PREPARATION OF CORE (FE OR CU)-SHELL (NOBLE METALS) NANOCOMPOSITES USING AQUEOUS ASCORBIC ACID

EPA Science Inventory

A greener method to fabricate novel core (Fe or Cu)-shell (noble metals) nanocomposites of transition metals such as Fe and Cu and noble metals such as Au, Pt, Pd, and Ag using aqueous ascorbic acid is described. Transition metal salts such as Cu and Fe were reduced using ascor...

Response to Marie Paz Morales' "Influence of Culture and Language Sensitive Physics on Science Attitude Achievement"

ERIC Educational Resources Information Center

Cole, Mikel Walker

2015-01-01

This response to Marie Paz Morales' "Influence of culture and language sensitive physics on science attitude achievement" explores the ideas of culturally responsive pedagogy and critical literacy to examine some implications for culturally responsive science instruction implicit in the original manuscript. [For "Influence of…

Elucidating the sole contribution from electromagnetic near-fields in plasmon-enhanced Cu 2O photocathodes

DOE PAGES

DuChene, Joseph S.; Williams, Benjamin P.; Johnston-Peck, Aaron C.; ...

2015-11-05

Despite many promising reports of plasmon-enhanced photocatalysis, the inability to identify the individual contributions from multiple enhancement mechanisms has delayed the development of general design rules for engineering efficient plasmonic photocatalysts. Herein, we construct a plasmonic photocathode comprised of Au@SiO 2 (core@shell) nanoparticles embedded within a Cu 2O nanowire network to exclusively examine the contribution from one such mechanism: electromagnetic near-field enhancement. The influence of the local electromagnetic field intensity is correlated with the overall light-harvesting efficiency of the device through variation of the SiO 2 shell thickness (5—22 nm) to systematically tailor the distance between the plasmonic Au nanoparticlesmore » and the Cu 2O nanowires. A three-fold increase in device photocurrent is achieved upon integrating the Au@SiO 2 nanoparticles into the Cu 2O nanowire network, further enabling a ~40% reduction in semiconductor film thickness while maintaining photocathode performance. Photoelectrochemical results are further correlated with photoluminescence studies and optical simulations to confirm that the near-field enhancement is the sole mechanism responsible for increased light absorption in the plasmonic photocathode.« less

Highly Active Au/δ-MoC and Cu/δ-MoC Catalysts for the Conversion of CO2: The Metal/C Ratio as a Key Factor Defining Activity, Selectivity, and Stability.

PubMed

Posada-Pérez, Sergio; Ramírez, Pedro J; Evans, Jaime; Viñes, Francesc; Liu, Ping; Illas, Francesc; Rodriguez, José A

2016-07-06

The ever growing increase of CO2 concentration in the atmosphere is one of the main causes of global warming. Thus, CO2 activation and conversion toward valuable added compounds is a major scientific challenge. A new set of Au/δ-MoC and Cu/δ-MoC catalysts exhibits high activity, selectivity, and stability for the reduction of CO2 to CO with some subsequent selective hydrogenation toward methanol. Sophisticated experiments under controlled conditions and calculations based on density functional theory have been used to study the unique behavior of these systems. A detailed comparison of the behavior of Au/β-Mo2C and Au/δ-MoC catalysts provides evidence of the impact of the metal/carbon ratio in the carbide on the performance of the catalysts. The present results show that this ratio governs the chemical behavior of the carbide and the properties of the admetal, up to the point of being able to switch the rate and mechanism of the process for CO2 conversion. A control of the metal/carbon ratio paves the road for an efficient reutilization of this environmental harmful greenhouse gas.

Highly active Au/δ-MoC and Cu/δ-MoC catalysts for the conversion of CO 2: The metal/C ratio as a key factor defining activity, selectivity, and stability

DOE PAGES

Posada-Pérez, Sergio; Ramírez, Pedro J.; Evans, Jaime; ...

2016-06-16

The ever growing increase of CO 2 concentration in the atmosphere is one of the main causes of global warming. Thus, CO 2 activation and conversion toward valuable added compounds is a major scientific challenge. A new set of Au/δ-MoC and Cu/δ-MoC catalysts exhibits high activity, selectivity, and stability for the reduction of CO 2 to CO with some subsequent selective hydrogenation toward methanol. Sophisticated experiments under controlled conditions and calculations based on density functional theory have been used to study the unique behavior of these systems. A detailed comparison of the behavior of Au/β-Mo 2C and Au/δ-MoC catalysts providesmore » evidence of the impact of the metal/carbon ratio in the carbide on the performance of the catalysts. The present results show that this ratio governs the chemical behavior of the carbide and the properties of the admetal, up to the point of being able to switch the rate and mechanism of the process for CO 2 conversion. Here, a control of the metal/carbon ratio paves the road for an efficient reutilization of this environmental harmful greenhouse gas.« less

Modeling of Disordered Binary Alloys Under Thermal Forcing: Effect of Nanocrystallite Dissociation on Thermal Expansion of AuCu3

NASA Astrophysics Data System (ADS)

Kim, Y. W.; Cress, R. P.

2016-11-01

Disordered binary alloys are modeled as a randomly close-packed assembly of nanocrystallites intermixed with randomly positioned atoms, i.e., glassy-state matter. The nanocrystallite size distribution is measured in a simulated macroscopic medium in two dimensions. We have also defined, and measured, the degree of crystallinity as the probability of a particle being a member of nanocrystallites. Both the distribution function and the degree of crystallinity are found to be determined by alloy composition. When heated, the nanocrystallites become smaller in size due to increasing thermal fluctuation. We have modeled this phenomenon as a case of thermal dissociation by means of the law of mass action. The crystallite size distribution function is computed for AuCu3 as a function of temperature by solving some 12 000 coupled algebraic equations for the alloy. The results show that linear thermal expansion of the specimen has contributions from the temperature dependence of the degree of crystallinity, in addition to respective thermal expansions of the nanocrystallites and glassy-state matter.

New geologic, fluid inclusion and stable isotope studies on the controversial Igarapé Bahia Cu-Au deposit, Carajás Province, Brazil

NASA Astrophysics Data System (ADS)

Dreher, Ana M.; Xavier, Roberto P.; Taylor, Bruce E.; Martini, Sérgio L.

2008-02-01

The Igarapé Bahia Cu-Au deposit in the Carajás Province, Brazil, is hosted by steeply dipping metavolcano-sedimentary rocks of the Igarapé Bahia Group. This group consists of a low greenschist grade unit of the Archean (˜2,750 Ma) Itacaiúnas Supergroup, in which other important Cu-Au and iron ore deposits of the Carajás region are also hosted. The orebody at Igarapé Bahia is a fragmental rock unit situated between chloritized basalt, with associated hyaloclastite, banded iron formation (BIF), and chert in the footwall and mainly coarse- to fine-grained turbidites in the hanging wall. The fragmental rock unit is a nearly concordant, 2 km long and 30-250 m thick orebody made up of heterolithic, usually matrix-supported rocks composed mainly of coarse basalt, BIF, and chert clasts derived from the footwall unit. Mineralization is confined to the fine-grained matrix and comprises disseminated to massive chalcopyrite accompanied by magnetite, gold, U- and light rare earth element (LREE)-minerals, and minor other sulfides like bornite, molybdenite, cobaltite, digenite, and pyrite. Gangue minerals include siderite, chlorite, amphibole, tourmaline, quartz, stilpnomelane, epidote, and apatite. A less important mineralization style at Igarapé Bahia is represented by late quartz-chalcopyrite-calcite veins that crosscut all rocks in the deposit area. Fluid inclusions trapped in a quartz cavity in the ore unit indicate that saline aqueous fluids (5 to 45 wt% NaCl + CaCl2 equiv), together with carbonic (CO2 ± CH4) and low-salinity aqueous carbonic (6 wt% NaCl equiv) fluids, were involved in the mineralization process. Carbonates from the fragmental layer have δ13C values from -6.7 to -13.4 per mil that indicate their origin from organic and possibly also from magmatic carbon. The δ34S values for chalcopyrite range from -1.1 to 5.6 per mil with an outlier at -10.8 per mil, implying that most sulfur is magmatic or leached from magmatic rocks, whereas a limited

Ultrasensitive detection of EGFR gene based on surface plasmon resonance enhanced electrochemiluminescence of CuZnInS quantum dots.

PubMed

Chen, Xueqian; Gui, Wenying; Ma, Qiang

2018-06-07

In our work, a novel DNA electrochemiluminescence (ECL) sensor based on CuZnInS quantum dots (QDs) and gold-nanoparticles (Au NPs) is developed for highly sensitive detection of epidermal growth factor receptor (EGFR) Gene, which has a close relation with the lung cancer. The CuZnInS QDs work as a novel kind of ECL luminophore, whose defect state emission is suitable for ECL sensing. To enhance the sensitivity of the sensing system, Au NPs are utilized creatively to strengthen the ECL intensity of CuZnInS QD S according to the surface plasmon resonance (SPR) effect. An ultrasensitive and universal detecting platform is built based on the SPR effect between Au NPs and CuZnInS QD S . The effect of the capped stabilizer on the ECL signal of QDs is firstly investigated. Three different stabilizers are used to cap the CuZnInS QDs, including mercaptopropionic acid (MPA), l-glutathione (GSH) and cysteamine (CA). MPA capped CuZnInS QDs possess the strongest ECL intensity among the three kinds of the CuZnInS QDs. Under the optimum conditions, a good linear relationship between ECL intensity and the concentration of target DNA is obtained in the range from 0.05 nmol L -1 to 1 nmol L -1 . The detection limit is 0.0043 nmol L -1 . The proposed DNA sensor has been employed for the determination of target DNA EGFR in human serum samples with satisfactory results. Copyright © 2018 Elsevier B.V. All rights reserved.

[Sensing of Cu²⁺ Based on Fenton Reaction and Unmodified Gold Nanoparticles].

PubMed

Xing, Yun-peng; Liu, Chun; Zhou, Xiao-hong; Zhang, Li-pei; Shi, Han-chang

2015-11-01

Heavy metal pollution has received great attentions in recent years. The traditional methods for heavy metal detection rely on the expensive laboratory instruments and need time-consuming preparation steps; therefore, it is urgent to develop quick and highly sensitive new technologies for heavy metal detection. The colorimetric method based on the gold nanoparticles (AuNPs) features with simple operation, high sensitivity and low cost, therefore, enabling it widely concerned and used in the environmental monitoring, food safety and chemical and biological sensing fields. This work developed a simple, rapid and highly sensitive strategy based on the Fenton reaction and unmodified AuNPs for the detection of Cu²⁺ in water samples. The hydroxyl radical ( · OH) generated by the Fenton reaction between the Cu²⁺ and sodium ascorbate (SA) oxidized the single stranded DNA (ssDNA) attached on the AuNPs surface into variable sequence fragments. The cleavage of ssDNA induced the aggregation of AuNPs in a certain salt solution, therefore, resulting in the changes on the absorbance of solution. The assay conditions were optimized to be pH value of 7.9, 11 mg · L⁻¹ ssDNA, 8 mmol · L⁻¹ SA and 70 mmol · L⁻¹ NaCl. Results showed that the absorbance ratio values at the wavelengths of 700 and 525 nm (A₇₀₀/A₅₂₅) were linearly correlated with the Cu²⁺ concentrations. The linear detection range was 0.1-10.0 µmol · L⁻¹ with a detection limit of 24 nmol · L⁻¹ (3σ). Spiked recoveries ranged from 87%-120% in three sorts of water, including drinking water, tap water and lake water, which confirmed that the potentials of the proposed assay for Cu²⁺ detection in reality.

Single crystal structure analyses of scheelite-powellite CaW1-xMoxO4 solidsolutions and unique occurrence in Jisyakuyama skarn deposits

NASA Astrophysics Data System (ADS)

Yamashita, K.; Yoshiasa, A.; Miyazaki, H.; Tokuda, M.; Tobase, T.; Isobe, H.; Nishiyama, T.; Sugiyama, K.; Miyawaki, R.

2017-12-01

Jisyakuyama skarn deposit, Fukuchi, Fukuoka, Japan, shows a simple occurrenceformed by penetration of hot water into limestone cracks. A unique occurrence of scheelite-powellite CaW1-xMoxO4 minerals is observed in the skarn deposit. Many syntheticexperiments for scheelite-powellite solid solutions have been reported as research onfluorescent materials. In this system it is known that a complete continuous solid solution isformed even at room temperature. In this study, we have carried out the chemical analyses,crystal structural refinements and detail description of occurrence on scheelite-powelliteminerals. We have also attempted synthesis of single crystal of solid solution in a widecomposition range. The chemical compositions were determined by JEOL scanningelectron microscope and EDS, INCA system. We have performed the crystal structurerefinements of the scheelite-powellite CaW1-xMoxO4 solid solutions (x=0.0-1.0) byRIGAKU single-crystal structure analysis system RAPID. The R and S values are around0.0s and 1.03. As the result of structural refinements of natural products and many solidsolutions, we confirm that most large natural single crystals have compositions at bothendmembers, and large solid solution crystals are rare. The lattice constants, interatomicdistances and other crystallographic parameters for the solid solution change uniquely withcomposition and it was confirmed as a continuous solid solution. Single crystals of scheeliteendmember + powellite endmember + solid solution with various compositions form anaggregate in the deposit (Figure 1). Crystal shapes of powellite and scheelite arehypidiomorphic and allotriomorphic, respectively. Many solid solution crystals areaccompanied by scheelite endmember and a compositional gap is observed betweenpowellite and solid-solution crystals. The presence of several penetration solutions withsignificantly different W and Mo contents may be assumed. This research can be expectedto lead to giving restrictive

Specific composition of native silver from the Rogovik Au-Ag deposit, Northeastern Russia

NASA Astrophysics Data System (ADS)

Kravtsova, R. G.; Tauson, V. L.; Palyanova, G. A.; Makshakov, A. S.; Pavlova, L. A.

2017-09-01

The first data on native silver from the Rogovik Au-Ag deposit in northeastern Russia are presented. The deposit is situated in central part of the Okhotsk-Chukchi Volcanic Belt (OCVB) in the territory of the Omsukchan Trough, unique in its silver resources. Native silver in the studied ore makes up finely dispersed inclusions no larger than 50 μm in size, which are hosted in quartz; fills microfractures and interstices in association with küstelite, electrum, acanthite, silver sulfosalts and selenides, argyrodite, and pyrite. It has been shown that the chemical composition of native silver, along with its typomorphic features, is a stable indication of the various stages of deposit formation and types of mineralization: gold-silver (Au-Ag), silver-base metal (Ag-Pb), and gold-silver-base metal (Au-Ag-Pb). The specificity of native silver is expressed in the amount of trace elements and their concentrations. In Au-Ag ore, the following trace elements have been established in native silver (wt %): up to 2.72 S, up to 1.86 Au, up to 1.70 Hg, up to 1.75 Sb, and up to 1.01 Se. Native silver in Ag-Pb ore is characterized by the absence of Au, high Hg concentrations (up to 12.62 wt %), and an increase in Sb, Se, and S contents; the appearance of Te, Cu, Zn, and Fe is notable. All previously established trace elements—Hg, Au, Sb, Se, Te, Cu, Zn, Fe, and S—are contained in native silver of Au-Ag-Pb ore. In addition, Pb appears, and silver and gold amalgams are widespread, as well as up to 24.61 wt % Hg and 11.02 wt % Au. Comparison of trace element concentrations in native silver at the Rogovik deposit with the literature data, based on their solubility in solid silver, shows that the content of chalcogenides (S, Se, Te) exceeds saturated concentrations. Possible mechanisms by which elevated concentrations of these elements are achieved in native silver are discussed. It is suggested that the appearance of silver amalgams, which is unusual for Au-Ag mineralization

Kinetics of Polydomain Ordering at Second-Order Phase Transitions (by the Example of the AuCu3 Alloy)

NASA Astrophysics Data System (ADS)

Feldman, E. P.; Stefanovich, L. I.; Gumennyk, K. V.

2008-08-01

Kinetics of polydomain spinodal ordering is studied in alloys of AuCu3 type. We introduce four non-conserved long-range order parameters whose sum, however, is conserved and, using the statistical approach, follow the temporal evolution of their random spatial distribution after a rapid temperature quench. A system of nonlinear differential equations for correlators of second and third order is derived. Asymptotical analysis of this system allows to investigate the scaling regime, which develops on the late stages of evolution and to extract additional information concerning the rate of decrease of the specific volume of disordered regions and the rate of decrease of the average thickness of antiphase boundaries. Comparison of these results to experimental data is given. The quench below the spinodal and the onset of long-range order may be separated by the incubation time, whose origin is different from that in first-order phase transitions. Numerical integration of equations for correlators shows also, that it is possible to prepare a sample in such a way that its further evolution will go with formation of transient kinetically slowed polydomain structures different from the final L12 structure.

Microwave surface resistance of bulk YBa2Cu3O6+x material

NASA Astrophysics Data System (ADS)

Fathy, A.; Kalokitis, D.; Belohoubek, E.; Sundar, H. G. K.; Safari, A.

1988-10-01

Superconducting Y-Ba-Cu-O samples were prepared by conventional solid-state reaction. The microwave surface resistance of 1:2:3 compound superconductor material was measured in a special disk resonator structure at 10 GHz. At liquid-nitrogen temperatures the microwave surface resistance is comparable to that of Au. At lower temperature (~10 K) the surface resistance is an order of magnitude lower than that of Au at the same temperature.

First Report of Widespread Wild Populations of Triatoma infestans (Reduviidae, Triatominae) in the Valleys of La Paz, Bolivia

PubMed Central

Buitrago, Rosio; Waleckx, Etienne; Bosseno, Marie-France; Zoveda, Faustine; Vidaurre, Pablo; Salas, Renata; Mamani, Elio; Noireau, François; Brenière, Simone Frédérique

2010-01-01

Wild populations of Triatoma infestans, the main vector of Chagas disease in the Southern Cone countries, may be involved in reinfestation of human dwellings, limiting the success of vector-control campaigns in Bolivia. Knowledge of the distribution of these populations remains incomplete. We report here the detection of T. infestans wild populations in large areas in the department of La Paz, Bolivia. Among 18 sylvatic areas investigated, 17 were positive with T. infestans specimens. The infection rate of captured T. infestans with Trypanosoma cruzi was 85.7% in adult specimens. These results expand the geographical distribution of wild populations of T. infestans; it may be distributed throughout the Inter-Andean Dry Forest eco-region of Bolivia. The current information allows us to propose the hypothesis that a sylvatic origin of the reinfestation is located in the valleys of La Paz. PMID:20348501

Geochemical Peculiarities of Galena and Sphalerite from Polymetallic Deposits of the Dal'negorskii Ore Region (Primorsky Krai, Russia)

NASA Astrophysics Data System (ADS)

Rogulina, L. I.; Moiseenko, V. G.; Ponomarchuk, V. A.

2018-04-01

New data on the composition of the major minerals from the skarn and vein polymetallic deposits of the Dal'negorskii ore region are reported. Analysis of galena and sphalerite was carried out by the X-ray fluorescent energy-dispersive method of synchrotron radiation for the first time. It is shown that the minor elements in major minerals of different deposits are typomorphic. Among these elements are Fe, Cu, Ni, Cd, Ag, Sn, and Sb, as well as In in sphalerite and Te in galena. The high concentrations of Ag, Cu, Te, Cd, and In in the extracted minerals indicate the complex character of mineralization. The compositional patterns of ore minerals characterize the sequence of mineral formation from the skarn to vein ores, and the sequence of deposits from the mesothermal to epithermal conditions. This provides geochemical evidence for the stage model of the formation of mineralization in the Dal'negorskii ore region.

Field and microcosm experiments to evaluate the effects of agricultural Cu treatment on the density and genetic structure of microbial communities in two different soils.

PubMed

Ranjard, Lionel; Echairi, Abdelwahad; Nowak, Virginie; Lejon, David P H; Nouaïm, Rachida; Chaussod, Rémi

2006-11-01

The effects of Cu amendment on indigenous soil microorganisms were investigated in two soils, a calcareous silty clay (Ep) and a sandy soil (Au), by means of a 1-year field experiment and a two-month microcosm incubation. Cu was added as 'Bordeaux mixture' [CuSO(4), Ca(OH)(2)] at the standard rate used in viticulture (B1=16 kg Cu kg(-1) soil) and at a higher level of contamination (B3=48 kg Cu ha(-1) soil). More extractable Cu was observed in sandy soil (Au) than in silty soil (Ep). Furthermore, total Cu and Cu-EDTA declined with time in Au soil, whereas they remained stable in Ep soil. Quantitative modifications of the microflora were assessed by C-biomass measurements and qualitative modifications were assessed by the characterization of the genetic structure of bacterial and fungal communities from DNA directly extracted from the soil, using B- and F-ARISA (bacterial and fungal automated ribosomal intergenic spacer analysis). In the field study, no significant modifications were observed in C-biomass whereas microcosm incubation showed a decrease in B3 contamination only. ARISA fingerprinting showed slight but significant modifications of bacterial and fungal communities in field and microcosm incubation. These modifications were transient in all cases, suggesting a short-term effect of Cu stress. Microcosm experiments detected the microbial community modifications with greater precision in the short-term, while field experiments showed that the biological effects of Cu contamination may be overcome or hidden by pedo-climatic variations.

Catalysis by Nanostructures: Methane, Ethylene Oxide, and Propylene Oxide Synthesis on Ag, Cu or Au Nanoclusters

DTIC Science & Technology

2008-02-07

22 nm) were prepared by reducing a Au salt, and encapsulating the Au nanoparticles formed in a polymer33 . A variety of high area oxides (TiO 2, ZnO ...Morphologies Utilizing a Combinatorial Electrochemistry Methodology. Ph. D. dissertation, Chemical Engineering, University of California, Santa Barbara (2004

Genetic Pd, Pt, Au, Ag, and Rh mineralogy in Noril'sk sulfide ores

NASA Astrophysics Data System (ADS)

Spiridonov, E. M.; Kulagov, E. A.; Serova, A. A.; Kulikova, I. M.; Korotaeva, N. N.; Sereda, E. V.; Tushentsova, I. N.; Belyakov, S. N.; Zhukov, N. N.

2015-09-01

The undeformed ore-bearing intrusions of the Noril'sk ore field (NOF) cut through volcanic rocks of the Late Permian-Early Triassic trap association folded in brachysynclines. Due to the nonuniform load on the roof of intrusive bodies, most sulfide melts were squeezed, up to the tops of ore-bearing intrusions; readily fusible Ni-Fe-Cu sulfide melts were almost completely squeezed. In our opinion, not only one but two stages of mineralization developed at the Noril'sk deposits: (i) syntrap magmatic and (ii) epigenetic post-trap metamorphic-hydrothermal. All platinum-group minerals (PGM) and minerals of gold are metasomatic in the Noril'sk ores. They replaced sulfide solid solutions and exsolution structures. All types of PGM and Au minerals occur in the ores, varying in composition from pyrrhotite to chalcopyrite, talnakhite, mooihoekite, and rich in galena; they are localized in the inner and outer contact zones and differ only in the quantitative proportions of ore minerals. The aureoles of PGM and Au-Ag minerals are wider than the contours of sulfide bodies and coincide with halos of fluid impact on orebodies and adjacent host rocks. The pneumatolytic PGM and Au-Ag minerals are correlated in abundance with the dimensions of sulfide bodies. Their amounts are maximal in veins of late fusible ore composed of eutectic PbS ss and iss intergrowths, as well as at their contacts. The Pd and Pt contents in eutectic sulfide ores of NOF are the world's highest. In the process of noble-metal mineral formation, the fluids supply Pd, Pt, Au, As, Sb, Sn, Bi, and a part of Te, whereas Fe, Ni, Cu, Pb, Ag, Rh, a part of Te and Pd are leached from the replaced sulfide minerals. The pneumatolytic PGM of the early stage comprises Pd and Pt intermetallic compounds enriched in Au along with Pd-Pt-Fe-Ni-Cu-Sn-Pb(As) and (Pd,Pt,Au)(Sn,Sb,Bi,Te,As) solid solutions. Pneumatolytic PGM and Au minerals of the middle stage are products of solid-phase transformation and recrystallization of

Polarimetric mountain based radio-occultation for rain detection: The ROHP-PAZ ground campaign

NASA Astrophysics Data System (ADS)

Padulles, Ramon; Cardellach, Estel; Tomas, Sergio; de la Torre, Manuel; Turk, Joe

2014-05-01

The Radio Occultation and Heavy Precipitation experiment aboard the PAZ Low Earth Orbiter (ROHP-PAZ) is a mission of opportunity: The Spanish Ministry of Science and Innovation (MICINN) approved in 2009 a proposal to include a polarimetric Global Navigation Satellite System (GNSS) Radio-Occultation (RO) payload on board of the Spanish Earth Observation satellite PAZ. This will be a new technique that has never been tested before, that aims to improve the knowledge of precipitation through simultaneous thermodynamic and vertical rain profiles. Prior to the launch of the satellite, expected for 2014, a ground experimental campaign is being conducted with the goal of starting the process of identifying and understanding all the factors that might affect the polarimetric RO observables. The campaign is being carried out at the top of Puig Sesolles, a 1667m peak in the Natural Park of Montseny (41º46'24 N, 2º26'17 E), 50 km N-NE from Barcelona, with clear views over the horizon to the South (East to West) direction, an area in which intense precipitation events tend to occur a few times per year. The campaign uses a ICE-CSIC/IEEC's GOLD-RTR open-loop receiver initially designed for collecting GNSS signals reflected off the sea surface. The receiver has been adjusted to track occulting GNSS radio-links. A double polarization (H and V) GNSS antenna has been designed and manufactured by the Polytechnic University of Barcelona (UPC) team for this particular ground-based experiment. The antenna is a phase-array made of 7 elements, each of them being a square patch built using a Rogers 4003 substrate, and symmetrically fed by four probes. It provides a pattern of 12.9 dB peak gain, 45 degrees half-power beam-width, and <-35 dB cross-polar isolation at the peak (better than -30 dB in the main lobe). The preliminary results show that not only precipitation, but also other factors are affecting the GNSS signal, wich means that the polarimetric signal is richer than expected

Mineral inclusions and SHRIMP U-Pb dating of zircons from the Alamas nephrite and granodiorite: Implications for the genesis of a magnesian skarn deposit

NASA Astrophysics Data System (ADS)

Liu, Yan; Zhang, Rongqing; Zhang, Zhiyu; Shi, Guanghai; Zhang, Qichao; Abuduwayiti, Maituohuti; Liu, Jianhui

2015-01-01

Extending approximately 1300 km and located in the Western Kunlun Mountains, the Hetian nephrite belt is the largest nephrite belt in the world and contains approximately 11 major deposits and more than 20 orebodies including the Alamas deposit. Hetian nephrite deposits can be classified as Mg-skarn deposits with Precambrian dolomitic marble host rock and green, green-white and white nephrite zones are distributed gradually in the zone of a granodiorite pluton. The green nephrite is mainly predominately composed of tremolite with generally minor to trace constituents of diopside, grossularitic garnet, actinolite and other minerals. Also green nephrite has higher content of TFe2O3, than green-white and white nephrites have. We subdivided the zircons from the green nephrites into four types, depending on their internal textures, mineral inclusions, and SHRIMP U-Pb ages. Type I zircons are round instead of idiomorphic in shape and lack obvious zoning. Type II and IV zircons have broad, clear oscillatory zoning and are hypidiomorphic or idiomorphic in shape; they contain inclusions of diopside, tremolite, chlorite and calcite. Most Type III zircons are narrow rims (< 10 μm) surrounding Type II and Type I zircons with highly luminous brightness and no zoning. Both Type I and Type II zircons have individual ages of 411 to 445 Ma and Type IV zircons have younger ages (388 to 406 Ma). Among the concordant ages, 425.7 ± 5.8 Ma and 420.0 ± 9.9 Ma for the QYZr1 and QYZr2 are consistent within error, with the 418.5 ± 2.8 Ma of the Alamas granodiorite formation age and the maximum age of the Alamas nephrite deposit. The partially recrystallization of zircons during skarn formation possibly lead to some younger individual ages (406.5 to 308 Ma). In the Western Kunlun Mountain, both Buya granite and Alamas grandiorite are high Ba-Sr granites and crystallized in Western Kunlun Orogen. The Buya granite formed at about 430 Ma in a post-orogenic tectonic environment. Considering

Late paleozoic base and precious metal deposits, East Tianshan, Xinjiang, China: Characteristics and geodynamic setting

USGS Publications Warehouse

Mao, J.; Goldfarb, R.J.; Wang, Y.; Hart, C.J.; Wang, Z.; Yang, J.

2005-01-01

The East Tianshan is a remote Gobi area located in eastern Xinjiang, northwestern China. In the past several years, a number of gold, porphyry copper, and Fe(-Cu) and Cu-Ag-Pb-Zn skarn deposits have been discovered there and are attracting exploration interest. The East Tianshan is located between the Junggar block to the north and early Paleozoic terranes of the Middle Tianshan to the south. It is part of a Hercynian orogen with three distinct E-W-trending tectonic belts: the Devonian-Early Carboniferous Tousuquan-Dananhu island arc on the north and the Carboniferous Aqishan - Yamansu rift basin to the south, which are separated by rocks of the Kanggurtag shear zone. The porphyry deposits, dated at 322 Ma, are related to the late evolutionary stages of a subduction-related oceanic or continental margin arc. In contrast, the skarn, gold, and magmatic Ni-Cu deposits are associated with post-collisional tectonics at ca. 290-270 Ma. These Late Carboniferous - Early Permian deposits are associated with large-scale emplacement and eruption of magmas possibly caused by lithosphere delamination and rifting within the East Tianshan.

Formation of a paleothermal anomaly and disseminated gold deposits associated with the Bingham Canyon porphyry Cu-Au-Mo system, Utah

USGS Publications Warehouse

Cunningham, C.G.; Austin, G.W.; Naeser, C.W.; Rye, R.O.; Ballantyne, G.H.; Stamm, R.G.; Barker, C.E.

2004-01-01

The thermal history of the Oquirrh Mountains, Utah, indicates that hydrothermal fluids associated with emplacement of the 37 Ma Bingham Canyon porphyry Cu-Au-Mo deposit extended at least 10 km north of the Bingham pit. An associated paleothermal anomaly enclosed the Barneys Canyon and Melco disseminated gold deposits and several smaller gold deposits between them. Previous studies have shown the Barneys Canyon deposit is near the outer limit of an irregular distal Au-As geochemical halo, about 3 km beyond an intermediate Pb-Zn halo, and 7 km beyond a proximal pyrite halo centered on the Bingham porphyry copper deposit. The Melco deposit also lies near the outer limit of the Au-As halo. Analysis of several geothermometers from samples collected tip to 22 km north of the Bingham Canyon porphyry Cu-Au-Mo deposit indicate that most sedimentary rocks of the Oquirrh Mountains, including those at the gold deposits, have not been regionally heated beyond the "oil window" (less than about 150??C). For geologically reasonable heating durations, the maximum sustained temperature at Melco, 6 km north of the Bingham pit, and at Barneys Canyon, 7.5 km north of the pit, was between 100??C and 140??C, as indicated by combinations of conodont color alteration indices of 1.5 to 2, mean random solid bitumen reflectance of about 1.0 percent, lack of annealing of zircon fission tracks, and partial to complete annealing of apatite fission tracks. The pattern of reset apatite fission-track ages indicates that the gold deposits are located approximately on the 120??C isotherm of the 37 Ma paleothermal anomaly assuming a heating duration of about 106 years. The conodont data further constrain the duration of heating to between 5 ?? 104 and 106 years at approximately 120??C. The ??18O of quartzite host rocks generally increases from about 12.6 per mil at the porphyry to about 15.8 per mil approximately 11 km from the Bingham deposit. This change reflects interaction of interstitial clays in

Multishelled Si@Cu Microparticles Supported on 3D Cu Current Collectors for Stable and Binder-free Anodes of Lithium-Ion Batteries.

PubMed

Zhang, Zailei; Wang, Zhong Lin; Lu, Xianmao

2018-04-24

Silicon has proved to be a promising anode material of high-specific capacity for the next-generation lithium ion batteries (LIBs). However, during repeated discharge/charge cycles, Si-based electrodes, especially those in microscale size, pulverize and lose electrical contact with the current collectors due to large volume expansion. Here, we introduce a general method to synthesize Cu@M (M = Si, Al, C, SiO 2 , Si 3 N 4 , Ag, Ti, Ta, SnIn 2 O 5 , Au, V, Nb, W, Mg, Fe, Ni, Sn, ZnO, TiN, Al 2 O 3 , HfO 2 , and TiO 2 ) core-shell nanowire arrays on Cu substrates. The resulting Cu@Si nanowire arrays were employed as LIB anodes that can be reused via HCl etching and H 2 -reduction. Multishelled Cu@Si@Cu microparticles supported on 3D Cu current collectors were further prepared as stable and binder-free LIB anodes. This 3D Cu@Si@Cu structure allows the interior conductive Cu network to effectively accommodate the volume expansion of the electrode and facilitates the contact between the Cu@Si@Cu particles and the current collectors during the repeated insertion/extraction of lithium ions. As a result, the 3D Cu@Si@Cu microparticles at a high Si-loading of 1.08 mg/cm 2 showed a capacity retention of 81% after 200 cycles. In addition, charging tests of 3D Cu@Si@Cu-LiFePO 4 full cells by a triboelectric nanogenerator with a pulsed current demonstrated that LIBs with silicon anodes can effectively store energy delivered by mechanical energy harvesters.

The oxidation state, and sulfur and Cu contents of arc magmas: implications for metallogeny

NASA Astrophysics Data System (ADS)

Richards, Jeremy P.

2015-09-01

. These sulfides may retain some highly siderophile elements in the source, but are unlikely to be sufficiently voluminous to significantly affect the budget of more modestly sulfide-compatible and more abundant elements such as Cu and Mo. These primary magmas can therefore be considered to be largely Cu-Mo-undepleted, although highly siderophile elements such as Au and platinum group elements (PGE) may be depleted unless no sulfides remain in the source. The latter condition seems unlikely during active subduction because of the continuous flux of fresh sulfur from the slab, but may occur during post-subduction re-melting (leading to potentially Au-rich post-subduction porphyry and alkalic-type epithermal systems). Lower crustal differentiation of main-stage arc magmas results in some loss of Cu to residual or cumulate sulfides, but again the amount appears to be minor, and does not drastically reduce the Cu content of derivative intermediate-composition melts. Fractionation and devolatilization affect the oxidation state of the magma in competing ways, but, while crystallization and segregation of Fe3 +-rich magnetite can cause reduction in reduced to moderately oxidized evolved magmas, this effect appears to be outweighed by the oxidative effects of degassing reduced or weakly oxidized gaseous species such as H2, H2S, and SIVO2, and preferential solvation and removal of Fe2 + in saline hydrothermal fluids. Consequently, most arc magmatic suites show slight increases in oxidation state during differentiation, reaching typical values of ΔFMQ = + 1 to + 2. This oxidation state is significant, because it corresponds to the transition from dissolved sulfide to sulfate dominance in magmas. It has been shown that Cu and Au solubilities in silicate magma increase up to this level (ΔFMQ ≈ + 1), but while Cu solubility continues to increase at higher oxidation states, Au shows a precipitous drop as sulfide, which solvates Au in the melt, is converted to sulfate. This may

SERS Assay for Copper(II) Ions Based on Dual Hot-Spot Model Coupling with MarR Protein: New Cu2+-Specific Biorecognition Element.

PubMed

Wang, Yulong; Su, Zhenhe; Wang, Limin; Dong, Jinbo; Xue, Juanjuan; Yu, Jiao; Wang, Yuan; Hua, Xiude; Wang, Minghua; Zhang, Cunzheng; Liu, Fengquan

2017-06-20

We have developed a rapid and ultrasensitive surface-enhanced Raman scattering (SERS) assay for Cu 2+ detection using the multiple antibiotic resistance regulator (MarR) as specific bridging molecules in a SERS hot-spot model. In the assay, Cu 2+ induces formation of MarR tetramers, which provide Au nanoparticle (NP)-AuNP bridges, resulting in the formation of SERS hot spots. 4-Mercaptobenzoic acid (4-MBA) was used as a Raman reporter. The addition of Cu 2+ increased the Raman intensity of 4-MBA. Use of a dual hot-spot signal-amplification strategy based on AuNP-AgNP heterodimers combined through antigen-antibody reactions increased the sensitivity of the sensing platform by 50-fold. The proposed method gave a linear response for Cu 2+ detection in the range of 0.5-1000 nM, with a detection limit of 0.18 nM, which is 5 orders of magnitude lower than the U.S. Environmental Protection Agency limit for Cu 2+ in drinking water (20 μM). In addition, all analyses can be completed in less than 15 min. The high sensitivity, high specificity, and rapid detection capacity of the SERS assay therefore provide a combined advantage over current assays.

Morphology-Controlled Synthesis of Au/Cu₂FeSnS₄ Core-Shell Nanostructures for Plasmon-Enhanced Photocatalytic Hydrogen Generation.

PubMed

Ha, Enna; Lee, Lawrence Yoon Suk; Man, Ho-Wing; Tsang, Shik Chi Edman; Wong, Kwok-Yin

2015-05-06

Copper-based chalcogenides of earth-abundant elements have recently arisen as an alternate material for solar energy conversion. Cu2FeSnS4 (CITS), a quaternary chalcogenide that has received relatively little attention, has the potential to be developed into a low-cost and environmentlly friendly material for photovoltaics and photocatalysis. Herein, we report, for the first time, the synthesis, characterization, and growth mechanism of novel Au/CITS core-shell nanostructures with controllable morphology. Precise manipulations in the core-shell dimensions are demonstrated to yield two distinct heterostructures with spherical and multipod gold nanoparticle (NP) cores (Au(sp)/CITS and Au(mp)/CITS). In photocatalytic hydrogen generation with as-synthesized Au/CITS NPs, the presence of Au cores inside the CITS shell resulted in higher hydrogen generation rates, which can be attributed to the surface plasmon resonance (SPR) effect. The Au(sp)/CITS and Au(mp)/CITS core-shell NPs enhanced the photocatalytic hydrogen generation by about 125% and 240%, respectively, compared to bare CITS NPs.

F4TCNQ on Cu, Ag, and Au as prototypical example for a strong organic acceptor on coinage metals

NASA Astrophysics Data System (ADS)

Rangger, Gerold M.; Hofmann, Oliver T.; Romaner, Lorenz; Heimel, Georg; Bröker, Benjamin; Blum, Ralf-Peter; Johnson, Robert L.; Koch, Norbert; Zojer, Egbert

2009-04-01

Metal work-function modification with the help of organic acceptors is an efficient tool to significantly enhance the performance of modern state-of-the-art organic molecular electronic devices. Here, the prototypical organic acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, F4TCNQ, is characterized on Ag(111), Au(111), and Cu(111) metal surfaces by means of density-functional theory calculations. Particular attention is paid to charge-transfer processes at the metal-organic interface; a subtle balance between charge forward and backward donations in combination with a strong adsorption-induced geometry change are found to be responsible for the observed increase in the system work function. A larger effect is obtained for the metals with larger initial work function. Interestingly, this results in similar charge-injection barriers from the substrate metal into an organic semiconductor deposited on top of the F4TCNQ layer. The impact of the F4TCNQ packing density of the electronic properties of the interface is also addressed. Comparing the calculated energy-level alignments and work-function modifications to experimental data from ultraviolet photoelectron spectroscopy yields good agreement between experiments and simulations.

Estimation of thermodynamic parameters for Au- and Mg-based metallic glasses

NASA Astrophysics Data System (ADS)

Gaur, Jitendra; Mishra, R. K.

2017-10-01

The study of temperature dependent thermodynamic parameters; Gibb's free energy difference (ΔG), entropy difference (ΔS) and enthalpy difference (ΔH) between the undercooled liquid and the corresponding equilibrium solid phases has been proved to be extremely advantageous in the study of the thermodynamic behaviour of Metallic glass (MG) forming melts. In last two decades, Au- and Mg-based alloys were found to form glass phases. In present study, the three thermodynamic parameters viz., ΔG, ΔS and ΔH are calculated theoretically in the entire temperature range Tm (melting temperature) to Tg (glass transition temperature) for both Au- and Mg-based five samples of MGs; Au77Ge13.6Si9.4, Au53.2Pb27.5Sb19.3, Au81.4Si18.6, Mg85.5Cu14.5 and Mg81.6Ga18.4 on the basis of Taylor's series expansion. A relative study is also made between the present result and the result obtained experimentally as well as on the basis of expressions projected by the earlier researchers. An attempt is also been made to narrate the reduced glass transition temperature with glass forming ability for all five MGs.

Kinetics and thermodynamics associated with Bi adsorption transitions at Cu and Ni grain boundaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tai, Kaiping; Feng, Lin; Dillon, Shen J.

The grain boundary diffusivity of Au in Cu and Cu-Bi, and Cu in Ni and Ni-Bi are characterized by secondary ion mass spectroscopy depth profiling. Samples are equilibrated in a Bi containing atmosphere at temperatures above and below the onset of grain boundary adsorption transitions, sometimes called complexion transitions. A simple thermo-kinetic model is used to estimate the relative entropic contributions to the grain boundary energies. The results indicate that the entropy term plays a major role in promoting thermally and chemically induced grain boundary complexion transition.

Role of magnetism in superconductivity of BaFe 2As 2: Study of 5d Au-doped crystals

DOE PAGES

Li, Li; Cao, Huibo; McGuire, Michael A.; ...

2015-09-09

We investigate properties of BaFe 2As 2 (122) single crystals upon gold doping, which is the transition metal with the highest atomic weight. The Au substitution into the FeAs-planes of 122 crystal structure (Au-122) is only possible up to a small amount of ~3%. We find that 5d is more effective in reducing magnetism in 122 than its counter 3d Cu, and this relates to superconductivity. We provide evidence of short-range magnetic fluctuations and local lattice inhomogeneities that may prevent strong percolative superconductivity in Ba(Fe 1-xAu x)2As 2.

Effect of silicon on activity coefficients of siderophile elements (Au, Pd, Pt, P, Ga, Cu, Zn, and Pb) in liquid Fe: Roles of core formation, late sulfide matte, and late veneer in shaping terrestrial mantle geochemistry

NASA Astrophysics Data System (ADS)

Righter, K.; Pando, K.; Humayun, M.; Waeselmann, N.; Yang, S.; Boujibar, A.; Danielson, L. R.

2018-07-01

Earth's core contains ∼10% of a light element that may be a combination of Si, S, C, O or H, with Si potentially being the major light element. Metal-silicate partitioning of siderophile elements can place important constraints on the P-T-fO2 and composition of the early Earth, but the effect of Si alloyed in Fe liquids is unknown for many of these elements. In particular, the effect of Si on the partitioning of highly siderophile elements (Au, Re and PGE) is virtually unknown. To address this gap in understanding, we have undertaken a systematic study of the highly siderophile elements Au, Pd, and Pt, and the volatile siderophile elements P, Ga, Cu, Zn, and Pb at variable Si content of metal, and 1600 °C and 1 GPa. From our experiments we derive epsilon interaction parameters between these elements and Si in Fe metallic liquids. The new parameters are used to update an activity model for trace siderophile elements in Fe alloys; Si causes large variation in the magnitude of activity coefficients of these elements in FeSi liquids. Because the interaction parameters are all positive, Si causes a decrease in their metal/silicate partition coefficients. We combine these new activity results with experimental studies of Au, Pd, Pt, P, Ga, Cu, Zn and Pb, to derive predictive expressions for metal/silicate partition coefficients which can then be applied to Earth. The expressions are applied to two scenarios for continuous accretion of Earth; specifically for constant and increasing fO2 during accretion. The results indicate that mantle concentrations of P, Ga, Cu, Zn, and Pb can be explained by metal-silicate equilibrium during accretion of the Earth where Earth's early magma ocean deepens to pressures of 40-60 GPa. Au, Pd, and Pt, on the other hand become too high in the mantle in such a scenario, and require a later removal mechanism, rather than an addition as traditionally argued. A late reduction event that removes 0.5% metal from a shallow magma ocean can lower

Selective determination of gold(III) ion using CuO microsheets as a solid phase adsorbent prior by ICP-OES measurement.

PubMed

Rahman, Mohammed M; Khan, Sher Bahadar; Marwani, Hadi M; Asiri, Abdullah M; Alamry, Khalid A; Al-Youbi, Abdulrahman O

2013-01-30

We have prepared calcined CuO microsheets (MSs) by a wet-chemical process using reducing agents in alkaline medium and characterized by UV/vis., fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD), and field-emission scanning electron microscopy (FESEM) etc. The detailed structural, compositional, and optical characterizations of the MSs were evaluated by XRD pattern, FT-IR, X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy, respectively which confirmed that the obtained MSs are well-crystalline CuO and possessed good optical properties. The CuO MSs morphology was investigated by FESEM, which confirmed that the calcined nanomaterials were sheet-shaped and grown in large-quantity. Here, the efficiency of the CuO MS was applied for a selective adsorption of gold(III) ion prior to its detection by inductively coupled plasma-optical emission spectrometry (ICP-OES). The selectivity of CuO MSs towards various metal ions, including Au(III), Cd(II), Co(II), Cr(III), Fe(III), Pd(II), and Zn(II) was analyzed. Based on the adsorption isotherm study, it was confirmed that the selectivity of MSs phase was mostly towards Au(III) ion. The static adsorption capacity for Au(III) was calculated to be 57.0 mg g(-1). From Langmuir adsorption isotherm, it was confirmed that the adsorption process was mainly monolayer-adsorption onto a surface containing a finite number of adsorption sites. Copyright © 2012 Elsevier B.V. All rights reserved.

Abundances of Ag and Cu in mantle peridotites and the implications for the behavior of chalcophile elements in the mantle

NASA Astrophysics Data System (ADS)

Wang, Zaicong; Becker, Harry

2015-07-01

Silver abundances in mantle peridotites and the behavior of Ag during high temperature mantle processes have received little attention and, as a consequence, the abundance of Ag in the bulk silicate Earth (BSE) has been poorly constrained. In order to better understand the processes that fractionate Ag and other chalcophile elements in the mantle, abundances of Ag and Cu in mantle peridotites from different geological settings (n = 68) have been obtained by isotope dilution ICP-MS methods. In peridotite tectonites and in a few suites of peridotite xenoliths which display evidence for variable extents of melt depletion and refertilization by silicate melts, Ag and Cu abundances show positive correlations with moderately incompatible elements such as S, Se, Te and Au. The mean Cu/Ag in fertile peridotites (3500 ± 1200, 1s, n = 38) is indistinguishable from the mean Cu/Ag of mid ocean ridge basalts (MORB, 3600 ± 400, 1s, n = 338) and MORB sulfide droplets. The constant mean Cu/Ag ratios indicate similar behavior of Ag and Cu during partial melting of the mantle, refertilization and magmatic fractionation, and thus should be representative of the Earth's upper mantle. The systematic fractionation of Cu, Ag, Au, S, Se and Te in peridotites and basalts is consistent with sulfide melt-silicate melt partitioning with apparent partition coefficients of platinum group elements (PGE) > Au ⩾ Te > Cu ≈ Ag > Se ⩾ S. Because of the effects of secondary processes, the abundances of chalcophile elements, notably S, Se, but also Cu and the PGE in many peridotite xenoliths are variable and lower than in peridotite massifs. Refertilization of peridotite may change abundances of chalcophile and lithophile elements in peridotite massifs, however, this seems to mostly occur in a systematic way. Correlations with lithophile and chalcophile elements and the overlapping mean Cu/Ag ratios of peridotites and ocean ridge basalts are used to constrain abundances of Ag and Cu in the BSE

Effect of the Silver Content of SnAgCu Solder on the Interfacial Reaction and on the Reliability of Angle Joints Fabricated by Laser-Jet Soldering

NASA Astrophysics Data System (ADS)

Ji, Hongjun; Ma, Yuyou; Li, Mingyu; Wang, Chunqing

2015-02-01

The silver content of lead-free solders affects their microstructure, the interfacial reaction, and the performance of the joints in reliability tests. In this study, Sn3.0Ag0.5Cu (wt.%, SAC305) and Sn1.0Ag0.5Cu (wt.%, SAC105) solder balls of diameter 55 μm were reflowed on gold surface pads by laser-jet soldering. It was found that four types of layered intermetallic compound (IMC) were formed at the interfaces; these were Au5Sn/AuSn, AuSn, AuSn2, and AuSn4 from the pad side to the solder matrix. The Au5Sn/AuSn eutectic region, thickness 400 nm, formed because of the high cooling rate induced by the laser-jet soldering. During high-temperature storage tests, the silver became segregated at the interfaces between the Au-Sn IMC and the solder matrix, resulting in inhibition of IMC growth in SAC305 joints, the shear strengths of which were higher than those of SAC105 joints. In mechanical drop tests, however, percentage failure of the SAC305 joints was twice that of the SAC105 joints.

Thermodynamic properties and equations of state for Ag, Al, Au, Cu and MgO using a lattice vibrational method

NASA Astrophysics Data System (ADS)

Jacobs, M.; Schmid-Fetzer, R.

2012-04-01

A prerequisite for the determination of pressure in static high pressure measurements, such as in diamond anvil cells is the availability of accurate equations of state for reference materials. These materials serve as luminescence gauges or as X-ray gauges and equations of state for these materials serve as secondary pressure scales. Recently, successful progress has been made in the development of consistency between static, dynamic shock-wave and ultrasonic measurements of equations of state (e.g. Dewaele et al. Phys. Rev. B70, 094112, 2004, Dorogokupets and Oganov, Doklady Earth Sciences, 410, 1091-1095, 2006, Holzapfel, High Pressure Research 30, 372-394, 2010) allowing testing models to arrive at consistent thermodynamic descriptions for X-ray gauges. Apart from applications of metallic elements in high-pressure work, thermodynamic properties of metallic elements are also of mandatory interest in the field of metallurgy for studying phase equilibria of alloys, kinetics of phase transformation and diffusion related problems, requiring accurate thermodynamic properties in the low pressure regime. Our aim is to develop a thermodynamic data base for metallic alloy systems containing Ag, Al, Au, Cu, Fe, Ni, Pt, from which volume properties in P-T space can be predicted when it is coupled to vibrational models. This mandates the description of metallic elements as a first step aiming not only at consistency in the pressure scales for the elements, but also at accurate representations of thermodynamic properties in the low pressure regime commonly addressed in metallurgical applications. In previous works (e.g. Jacobs and de Jong, Geochim. Cosmochim. Acta, 71, 3630-3655, 2007, Jacobs and van den Berg, Phys. Earth Planet. Inter., 186, 36-48, 2011) it was demonstrated that a lattice vibrational framework based on Kieffer's model for the vibrational density of states, is suitable to construct a thermodynamic database for Earth mantle materials. Such a database aims at

Investigation on the age of mineralization in the Sungun porphyry Cu-Mo deposit, NW Iran with a regional metallogenic perspective

NASA Astrophysics Data System (ADS)

Simmonds, Vartan; Moazzen, Mohssen; Mathur, Ryan

2016-04-01

The Sungun porphyry copper deposit (PCD) is located in NW Iran, neighbouring several other PCDs and prospects in the region and the Lesser Caucasus (south Armenia). It lies on the Urumieh-Dokhtar magmatic arc (UDMA), which formed through the northeast-ward subduction of the Neo-Tethyan oceanic crust beneath the Central Iranian plate during late-Mesozoic and early-Cenozoic [1], and hosts the porphyry copper metallogenic belt of Iran. The Sungun PCD is the second largest deposit in Iran with ore reserves of about 850 Mt at 0.62 wt% Cu and 0.01 wt% Mo and probable reserves over 1Gt. The monzonitic to quartz monzonitic porphyry stock intruded the upper Cretaceous carbonates and Eocene volcano-sedimentary rocks. It produced a skarn-type mineralization at its contact zone with the carbonate rocks, as well as vast hydrothermal alteration zones and porphyry-type Cu and Mo mineralization. The zircon U-Pb age of the host porphyry stock is about 22.5±0.4 to 20.1±0.4 Ma [2]. Re-Os dating of four molybdenite separates from this PCD shows ages ranging between 22.9±0.2 to 21.7±0.2 Ma, with an average of 22.57±0.2 Ma, corresponding to the early Miocene (Aquitanian). These ages indicate that both the porphyry stock and the Cu-Mo mineralization are post-collisional events, similar to many other deposits and prospects in NW and central Iran and south Armenia, and the mineralization occurred shortly after the emplacement of the host stock, corresponding better to the ages obtained from the marginal parts of the stock. Magmatism and mineralization in Sungun coincides with the third metallogenic epoch in the Lesser Caucasus (Eocene to Miocene; [3]), though it is considerably younger than all of the dated PCDs and prospects in the south Armenia. It also postdates Cu-Mo mineralizations in the Saheb Divan (35 Ma), Qaradagh batholith (31.22±0.28 to 25.19±0.19 Ma), as well as Haft Cheshmeh PCD (28.18±0.42 to 27.05±0.37 Ma) in NW Iran, while it seems to be coeval with the Kighal