New high- and low-temperature apparatus for synchrotron polycrystalline X-ray diffraction.

PubMed

Tang, C C; Bushnell-Wye, G; Cernik, R J

1998-05-01

A high-temperature furnace with an induction heater coil and a cryogenic system based on closed-cycle refrigeration have been assembled to enhance the non-ambient powder diffraction facilities at the Synchrotron Radiation Source, Daresbury Laboratory. The commissioning of the high- and low-temperature devices on the high-resolution powder diffractometer of Station 2.3 is described. The combined temperature range provided by the furnace/cryostat is 10-1500 K. Results from Fe and NH(4)Br powder samples are presented to demonstrate the operation of the apparatus. The developments presented in this paper are applicable to a wide range of other experiments and diffraction geometries.

New software to model energy dispersive X-ray diffraction in polycrystalline materials

NASA Astrophysics Data System (ADS)

Ghammraoui, B.; Tabary, J.; Pouget, S.; Paulus, C.; Moulin, V.; Verger, L.; Duvauchelle, Ph.

2012-02-01

Detection of illicit materials, such as explosives or drugs, within mixed samples is a major issue, both for general security and as part of forensic analyses. In this paper, we describe a new code simulating energy dispersive X-ray diffraction patterns in polycrystalline materials. This program, SinFullscat, models diffraction of any object in any diffractometer system taking all physical phenomena, including amorphous background, into account. Many system parameters can be tuned: geometry, collimators (slit and cylindrical), sample properties, X-ray source and detector energy resolution. Good agreement between simulations and experimental data was obtained. Simulations using explosive materials indicated that parameters such as the diffraction angle or the energy resolution of the detector have a significant impact on the diffraction signature of the material inspected. This software will be a convenient tool to test many diffractometer configurations, providing information on the one that best restores the spectral diffraction signature of the materials of interest.

Low dose radiation damage effects in silicon strip detectors

NASA Astrophysics Data System (ADS)

Wiącek, P.; Dąbrowski, W.

2016-11-01

The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

The binary system K2SO4CaSO4

USGS Publications Warehouse

Rowe, J.J.; Morey, G.W.; Hansen, I.D.

1965-01-01

The binary system K2SO4CaSO4 was studied by means of heating-cooling curves, differential thermal analysis, high-temperature quenching technique and by means of a heating stage mounted on an X-ray diffractometer. Compositions and quench products were identified optically and by X-ray. Limited solid solution of CaSO4 in K2SO4 was found. There is a eutectic at 875??C and 34 wt. per cent CaSO4. Calcium langbeinite melts incongruently at 1011??C. The melting-point of CaSO4 (1462??C) was determined by the quenching technique using sealed platinum tubes. The only intermediate crystalline phase found in the system is K2SO4??2CaSO4 (calcium langbeinite). ?? 1965.

Properties of WO3-x Electrochromic Thin Film Prepared by Reactive Sputtering with Various Post Annealing Temperatures

NASA Astrophysics Data System (ADS)

Kim, Min Hong; Choi, Hyung Wook; Kim, Kyung Hwan

2013-11-01

The WO3-x thin films were prepared on indium tin oxide (ITO) coated glass at 0.7 oxygen flow ratio [O2/(Ar+O2)] using the facing targets sputtering (FTS) system at room temperature. In order to obtain the annealing effect, as-deposited thin films were annealed at temperatures of 100, 200, 300, 400, and 500 °C for 1 h in open air. The structural properties of the WO3-x thin film were measured using an X-ray diffractometer. The WO3-x thin films annealed at up to 300 °C indicated amorphous properties, while those annealed above 400 °C indicated crystalline properties. The electrochemical and optical properties of WO3-x thin films were measured using cyclic voltammetry and a UV/vis spectrometer. The maximum value of coloration efficiency obtained was 34.09 cm2/C for thin film annealed at 200 °C. The WO3-x thin film annealed at 200 °C showed superior electrochromic properties.

Thermal vacancies and phase separation in bcc mixtures of helium-3 and helium-4

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

Fraass, Benedick Andrew

1980-01-01

Thermal vacancy concentrations in crystals of 3He- 4He mixtures have been determined. A new x-ray diffractometer-position sensitive detector system is used to make measurements of the absolute lattice parameter of the helium crystals with an accuracy of 300 ppM, and measurements of changes in lattice parameters to better than 60 ppM. The phase separation of the concentrated 3He- 4He mixtures has been studied in detail with the x-ray measurements. Vacancy concentrations in crystals with 99%, 51%, 28%, 12%, and 0% 3He have been determined. Phase separation has been studied in mixed crystals with concentrations of 51%, 28%, and 12% 3Hemore » and melting pressures between 3.0 and 6.1 MPa. The phase separation temperatures determined in this work are in general agreement with previous work. The pressure dependence of T c, the phase separation temperature for a 50% mixture, is found to be linear: dT c/dP = -34 mdeg/MPa. The x-ray measurements are used to make several comments on the low temperature phase diagram of the helium mixtures.« less

Effect of Doping Materials on the Low-Level NO Gas Sensing Properties of ZnO Thin Films

NASA Astrophysics Data System (ADS)

Çorlu, Tugba; Karaduman, Irmak; Yildirim, Memet Ali; Ateş, Aytunç; Acar, Selim

2017-07-01

In this study, undoped, Cu-doped, and Ni-doped ZnO thin films have been successfully prepared by successive ionic layer adsorption and reaction method. The structural, compositional, and morphological properties of the thin films are characterized by x-ray diffractometer, energy dispersive x-ray analysis (EDX), and scanning electron microscopy, respectively. Doping effects on the NO gas sensing properties of these thin films were investigated depending on gas concentration and operating temperature. Cu-doped ZnO thin film exhibited a higher gas response than undoped and Ni-doped ZnO thin film at the operating temperature range. The sensor with Cu-doped ZnO thin film gave faster responses and recovery speeds than other sensors, so that is significant for the convenient application of gas sensor. The response and recovery speeds could be associated with the effective electron transfer between the Cu-doped ZnO and the NO molecules.

Investigation on thermo physical characteristics of ethylene glycol based Al:ZnO nanofluids

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

Kiruba, R., E-mail: krbranjini@gmail.com, E-mail: drkingson@karunya.edu; George, Ritty; Gopalakrishnan, M.

2015-06-24

The present work describes the experimental aspects of viscosity and thermal conductivity characteristics of nanofluids. Aluminium doped zinc oxide nanostructures were synthesized by chemical precipitation method. Ultrasonic technique is used to disperse the nanostructures in ethylene glycol. Structural and morphological properties of Al doped ZnO nanostructures are characterized using X-ray diffractometer and scanning electron microscopic technique. The effect of concentration and temperature on thermo-physical properties of Al/ZnO nanofluids is also investigated. The experimental results showed there is enhancement in thermal conductivity with rise in temperature which can be utilized for coolant application.

Short review on chemical bath deposition of thin film and characterization

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

Mugle, Dhananjay, E-mail: dhananjayforu@gmail.com; Jadhav, Ghanshyam, E-mail: ghjadhav@rediffmail.com

2016-05-06

This reviews the theory of early growth of the thin film using chemical deposition methods. In particular, it critically reviews the chemical bath deposition (CBD) method for preparation of thin films. The different techniques used for characterizations of the chemically films such as X-ray diffractometer (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Electrical conductivity and Energy Dispersive Spectroscopy (EDS) are discussed. Survey shows the physical and chemical properties solely depend upon the time of deposition, temperature of deposition.

Sizes of X-ray radiation coherent domains in thin SmS films and their visualization

NASA Astrophysics Data System (ADS)

Sharenkova, N. V.; Kaminskii, V. V.; Petrov, S. N.

2011-09-01

The size of X-ray radiation coherent domains (250 ± 20 Å) is determined in a thin polycrystalline SmS film using X-ray diffraction patterns (θ-2θ scanning, DRON-2 diffractometer, Cu K α radiation) and the Selyakov-Scherrer formula with allowance for the effect of microstrains. An image of this film is taken with a transmission electron microscope, and regions with a characteristic size of 240 Å are clearly visible in it. It is concluded that X-ray radiation coherent domains are visualized.

Study on the surface sulfidization behavior of smithsonite at high temperature

NASA Astrophysics Data System (ADS)

Lv, Jin-fang; Tong, Xiong; Zheng, Yong-xing; Xie, Xian; Wang, Cong-bing

2018-04-01

Surface sulfidization behavior of smithsonite at high temperature was investigated by X-ray powder diffractometer (XRD) along with thermodynamic calculation, X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA). The XRD and thermodynamic analyses indicated that the smithsonite was decomposed into zincite at high temperatures. After introducing a small amount of pyrite, artificial sulfides were formed at surface of the obtained zincite. The XPS analyses revealed that the sulfide species including zinc sulfide and zinc disulfide were generated at the zincite surface. The EPMA analyses demonstrated that the film of sulfides was unevenly distributed at the zincite surface. The average concentration of elemental sulfur at the sample surface increased with increasing of pyrite dosage. A suitable mole ratio of FeS2 to ZnCO3 for the surface thermal modification was determined to be about 0.3. These findings can provide theoretical support for improving the process during which the zinc recovery from refractory zinc oxide ores is achieved by xanthate flotation.

Multifunctionality of nanocrystalline lanthanum ferrite

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

Rai, Atma, E-mail: atma@iitp.ac.in; Thakur, Awalendra K.; Centre for Energy and Environment, Indian Institute of Technology Patna 800013 India

2016-05-06

Nanocrystalline lanthanum ferrite has been synthesized by adopting modified Pechini route. No evidence of impurity or secondary phase has been detected up to the detection of error limit of X-ray diffractometer (XRD). Rietveld refinement of X-ray diffraction pattern reveals orthorhombic crystal system with space group Pnma (62).Crystallite size and lattice strain was found to be ∼42.8nm and 0.306% respectively. Optical band gap was found to be 2.109 eV, by UV-Visible diffused reflectance spectrum (DRS). Brunauer-Emmet-Teller (BET) surface area was found to be ∼3.45 m{sup 2}/g. Magnetization-hysteresis (M-H) loop was recorded at room temperature (300K) reveals weak ferromagnetism in Nanocrystalline lanthanummore » ferrite. The weak ferromagnetism in lanthanum ferrite is due to the uncompensated antiferromagnetic spin ordering. Ferroelectric loop hysteresis observed at room temperature at 100Hz depicts the presence of ferroelectric ordering in LaFeO{sub 3}.Simultanious presence of magnetic and ferroelectric ordering at room temperature makes it suitable candidate of Multiferroic family.« less

Multifunctionality of nanocrystalline lanthanum ferrite

NASA Astrophysics Data System (ADS)

Rai, Atma; Thakur, Awalendra K.

2016-05-01

Nanocrystalline lanthanum ferrite has been synthesized by adopting modified Pechini route. No evidence of impurity or secondary phase has been detected up to the detection of error limit of X-ray diffractometer (XRD). Rietveld refinement of X-ray diffraction pattern reveals orthorhombic crystal system with space group Pnma (62).Crystallite size and lattice strain was found to be ˜42.8nm and 0.306% respectively. Optical band gap was found to be 2.109 eV, by UV-Visible diffused reflectance spectrum (DRS). Brunauer-Emmet-Teller (BET) surface area was found to be ˜3.45 m2/g. Magnetization-hysteresis (M-H) loop was recorded at room temperature (300K) reveals weak ferromagnetism in Nanocrystalline lanthanum ferrite. The weak ferromagnetism in lanthanum ferrite is due to the uncompensated antiferromagnetic spin ordering. Ferroelectric loop hysteresis observed at room temperature at 100Hz depicts the presence of ferroelectric ordering in LaFeO3.Simultanious presence of magnetic and ferroelectric ordering at room temperature makes it suitable candidate of Multiferroic family.

Effect of oxidizer to fuel molar ratio on particle size and DC conductivity of CeO{sub 2} nanoparticles

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

Harish, B. M.; Rajeeva, M. P.; Naveen, C. S.

2016-05-06

Cerium oxide nanoparticles were synthesized by solution combustion method with varying the oxidizer (cerium nitrate hexa hydrate) to fuel (Glycine) molar ratio. The prepared samples were characterized by UV-visible spectrometer, X-ray diffractometer (XRD), Scanning electron microscope (SEM) and Energy dispersive X-Ray analysis (EDAX). XRD pattern reveals the formation of cubic fluorite structure of CeO{sub 2}. It was observed that finest crystallites were found at extreme fuel-deficient condition and it is good enough to produce favorable powder characteristics. The average crystallite size was found to be 14.46 nm to 21.57 nm. The temperature dependent dc conductivity was carried out using Keithleymore » source meter between the temperature range from 300 K to 573 K. From this study it was found that the conductivity increases with increase of temperature due to semiconducting behavior of CeO{sub 2} and it decreases with particle size due to increase in the energy band gap.« less

In situ surface/interface x-ray diffractometer for oxide molecular beam epitaxy

DOE PAGES

Lee, J. H.; Tung, I. C.; Chang, S. -H.; ...

2016-01-05

In situ studies of oxide molecular beam epitaxy by synchrotron x-ray scattering has been made possible by upgrading an existing UHV/molecular beam epitaxy (MBE) six-circle diffractometer system. For oxide MBE growth, pure ozone delivery to the chamber has been made available, and several new deposition sources have been made available on a new 12 in. CF (ConFlat, a registered trademark of Varian, Inc.) flange. X-ray diffraction has been used as a major probe for film growth and structures for the system. In the original design, electron diffraction was intended for the secondary diagnostics available without the necessity of the x-raymore » and located at separate positions. Deposition of films was made possible at the two diagnostic positions. And, the aiming of the evaporation sources is fixed to the point between two locations. Ozone can be supplied through two separate nozzles for each location. Also two separate thickness monitors are installed. Finally, additional features of the equipment are also presented together with the data taken during typical oxide film growth to illustrate the depth of information available via in situ x-ray techniques.« less

HA/Bioglass composite films deposited by pulsed laser with different substrate temperature

NASA Astrophysics Data System (ADS)

Wang, D. G.; Chen, C. Z.; Jin, Q. P.; Li, H. C.; Pan, Y. K.

2014-03-01

In this experiment, the HA/Bioglass composite films on Ti-6Al-4V were deposited by a pulsed laser at Ar atmosphere, and the influence of substrate temperature on the morphology, phase constitutions, bonding configurations and adhesive strength of the films was studied. The obtained films were characterized by an electron probe microanalyzer (EPMA), scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), scratch apparatus, and so on. The results show that the amount of the droplets, the crystallinity, and the critical load of the deposited films all increase with the increase of the substrate temperature; however, the substrate temperature has little influence on the functional groups of the films.

Titration of a Solid Acid Monitored by X-Ray Diffraction

ERIC Educational Resources Information Center

Dungey, Keenan E.; Epstein, Paul

2007-01-01

An experiment is described to introduce students to an important class of solid-state reactions while reinforcing concepts of titration by using a pH meter and a powder X-ray diffractometer. The experiment was successful in teaching students the abstract concepts of solid-state structure and diffraction by applying the diffraction concepts learned…

Laboratory and In-Flight In-Situ X-ray Imaging and Scattering Facility for Materials, Biotechnology and Life Sciences

NASA Technical Reports Server (NTRS)

2003-01-01

We propose a multifunctional X-ray facility for the Materials, Biotechnology and Life Sciences Programs to visualize formation and behavior dynamics of materials, biomaterials, and living organisms, tissues and cells. The facility will combine X-ray topography, phase micro-imaging and scattering capabilities with sample units installed on the goniometer. This should allow, for the first time, to monitor under well defined conditions, in situ, in real time: creation of imperfections during growth of semiconductors, metal, dielectric and biomacromolecular crystals and films, high-precision diffraction from crystals within a wide range of temperatures and vapor, melt, solution conditions, internal morphology and changes in living organisms, tissues and cells, diffraction on biominerals, nanotubes and particles, radiation damage, also under controlled formation/life conditions. The system will include an ultrabright X-ray source, X-ray mirror, monochromator, image-recording unit, detectors, and multipurpose diffractometer that fully accommodate and integrate furnaces and samples with other experimental environments. The easily adjustable laboratory and flight versions will allow monitoring processes under terrestrial and microgravity conditions. The flight version can be made available using a microsource combined with multilayer or capillary optics.

Cryogenic coherent X-ray diffraction imaging of biological samples at SACLA: a correlative approach with cryo-electron and light microscopy.

PubMed

Takayama, Yuki; Yonekura, Koji

2016-03-01

Coherent X-ray diffraction imaging at cryogenic temperature (cryo-CXDI) allows the analysis of internal structures of unstained, non-crystalline, whole biological samples in micrometre to sub-micrometre dimensions. Targets include cells and cell organelles. This approach involves preparing frozen-hydrated samples under controlled humidity, transferring the samples to a cryo-stage inside a vacuum chamber of a diffractometer, and then exposing the samples to coherent X-rays. Since 2012, cryo-coherent diffraction imaging (CDI) experiments have been carried out with the X-ray free-electron laser (XFEL) at the SPring-8 Ångstrom Compact free-electron LAser (SACLA) facility in Japan. Complementary use of cryo-electron microscopy and/or light microscopy is highly beneficial for both pre-checking samples and studying the integrity or nature of the sample. This article reports the authors' experience in cryo-XFEL-CDI of biological cells and organelles at SACLA, and describes an attempt towards reliable and higher-resolution reconstructions, including signal enhancement with strong scatterers and Patterson-search phasing.

Temperature-Dependent Magnetic Response of Antiferromagnetic Doping in Cobalt Ferrite Nanostructures.

PubMed

Nairan, Adeela; Khan, Maaz; Khan, Usman; Iqbal, Munawar; Riaz, Saira; Naseem, Shahzad

2016-04-18

In this work Mn x Co 1- x Fe₂O₄ nanoparticles (NPs) were synthesized using a chemical co-precipitation method. Phase purity and structural analyses of synthesized NPs were performed by X-ray diffractometer (XRD). Transmission electron microscopy (TEM) reveals the presence of highly crystalline and narrowly-dispersed NPs with average diameter of 14 nm. The Fourier transform infrared (FTIR) spectrum was measured in the range of 400-4000 cm -1 which confirmed the formation of vibrational frequency bands associated with the entire spinel structure. Temperature-dependent magnetic properties in anti-ferromagnet (AFM) and ferromagnet (FM) structure were investigated with the aid of a physical property measurement system (PPMS). It was observed that magnetic interactions between the AFM (Mn) and FM (CoFe₂O₄) material arise below the Neel temperature of the dopant. Furthermore, hysteresis response was clearly pronounced for the enhancement in magnetic parameters by varying temperature towards absolute zero. It is shown that magnetic properties have been tuned as a function of temperature and an externally-applied field.

High Rate Deposition of Thick CrN and Cr2N Coatings Using Modulated Pulse Power (MPP) Magnetron Sputtering

DTIC Science & Technology

2010-12-01

in the conventional Bragg-Bentano mode. The residual stress of the coatings was measured by glancing incident angle XRD (GIXRD) in the same X - ray ...micro-analysis (EPMA), x - ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), nanoindentation, scratch test, and ball-on...the coatings was determined by XRD using a SIEMENS X - ray diffractometer (Model KRISTALLOFLEX-810) operated with K-alpha Cu radiation (30 kV and 20 mA

The SPRING Nanoenergetics Hub at UTD

DTIC Science & Technology

2008-12-01

synthesis and processing of advanced nanostructured materials, the structure and property characterization needed for materials optimization, the...nano-particles into hexane solvent a deposited films. Here we are modeling that processes to see how the droplet evaporation progresses in time. What...nanofibers was determined by powder X-ray diffraction (XRD) (Scintag XDS 2000 X-ray diffractometer with Cu Ka radiation). The fiber morphology was

Alloy composition effects on oxidation products of VIA, B-1900, 713C, and 738X: A high temperature diffractometer study

NASA Technical Reports Server (NTRS)

Garlick, R. G.; Lowell, C.

1973-01-01

High temperature X-ray diffraction studies were performed to investigate isothermal and cyclic oxidation at 1000 and 1100 C of the nickel-base superalloys VIA, B-1900, 713C, and 738X. Oxidation was complex. The major oxides, Al2O3, Cr2O3, and the spinels, formed in amounts consistent with alloy chemistry. The alloys VIA and B-1900 (high Al, low Cr alloys) tended to form Al2O3 and NiAl2O4; 738X (high Cr, low Al) formed Cr2O3 and NiCr2O4. A NiTa2O6 type of oxide formed in amounts approximately proportional to the refractory metal content of the alloy. One of the effects of cycling was to increase the amount of spinels formed.

Synchrotron radiation topography studies of the phase transition in LaGaO 3 crystals

NASA Astrophysics Data System (ADS)

Yao, G.-D.; Dudley, M.; Wang, Y.; Liu, X.; Liebermann, R. C.

1991-05-01

An investigation of the orthorhombic to rhombohedral phase transformation occurring at 145°C in lanthanum gallate has been conducted using white beam synchrotron X-ray topography (WBSXRT). The existence of the first order transition was confirmed by differential thermal analysis and X-ray diffractometer powder analysis. Subsequent to this, synchrotron white beam Laue patterns were recorded in situ as a function of temperature, during the transition. Before the transition point was reached, (112) orth type reflection twinning was found to be dominant although a small amount of (110) orth type twinning was also observed in the same crystal. Beyond the transition point, not only did the structural change become evident but also reflection twinning on the (110) rhom planes was observed. The scale of this twinning became finer as the temperature was increased beyond the transition temperature. The twinning observed in both the low and high temperature phases gives rise to deformation of the (011) rhom surface plane which creates problems for the potential use of this material as a substrate for growing high Tc superconducting epitaxial layers.

Experiment to Determine the Absorption Coefficient of Gamma Rays as a Function of Energy.

ERIC Educational Resources Information Center

Ouseph, P. J.; And Others

1982-01-01

Simpler than x-ray diffractometer experiments, the experiment described illustrates certain concepts regarding the interaction of electromagnetic rays with matter such as the exponential decrease in the intensity with absorber thickness, variation of the coefficient of absorption with energy, and the effect of the K-absorption edge on the…

The influence of temperature on a nutty-cake structural material: LiMn1-xFexPO4 composite with LiFePO4 core and carbon outer layer for lithium-ion battery

NASA Astrophysics Data System (ADS)

Huo, Zhen-Qing; Cui, Yu-Ting; Wang, Dan; Dong, Yue; Chen, Li

2014-01-01

The extremely low electronic conductivity, slow ion diffusion kinetics, and the Jahn-Teller effect of LiMnPO4 limit its electrochemical performance. In this work, a nutty-cake structural C-LiMn1-xFexPO4-LiFePO4 cathode material is synthesized by hydrothermal method and further calcined at different temperatures. The influence of calcination temperature on the electrochemical behavior is investigated by X-ray diffractometer, scanning electron microscope, field-emission high-resolution transmission electron microscope, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and charge-discharge tests. And the performance of C-LiMn1-xFexPO4-LiFePO4 materials has a relationship with its crystal structure. The well-crystallized Sample-600 calcined at 600 °C shows the smallest charge transfer resistance, the largest lithium ion diffusion coefficient (DLi) and the best cycling stability. The discharge capacity of Sample-600 holds around 112 mAh g-1 after the 3rd cycle at 0.1 C rate. The performances improvement of C-LiMn1-xFexPO4-LiFePO4 material can be mainly attributed to the iron diffusion from the LiFePO4 core to the outer LiMnPO4 layer under appropriate calcination temperature.

An X-ray diffractometer using mirage diffraction

PubMed Central

Fukamachi, Tomoe; Jongsukswat, Sukswat; Ju, Dongying; Negishi, Riichirou; Hirano, Keiichi; Kawamura, Takaaki

2014-01-01

Some characteristics are reported of a triple-crystal diffractometer with a (+, −, +) setting of Si(220) using mirage diffraction. The first crystal is flat, while the second and third crystals are bent. Basically, the first crystal is used as a collimator, the second as a monochromator and the third as the sample. The third crystal also works as an analyzer. The advantages of this diffractometer are that its setup is easy, its structure is simple, the divergence angle from the second crystal is small and the energy resolution of the third crystal is high, of the order of sub-meV. PMID:25242911

A facile approach for the fabrication of 3D flower-like Cu2S nanostructures on brass mesh with temperature-induced wetting transition for efficient oil-water separation

NASA Astrophysics Data System (ADS)

Niu, Lei; Kang, Zhixin

2017-11-01

3D flower-like Cu2S nanostructures on brass meshes have been fabricated for the first time, with a reversible wetting transition and excellent durability. In the present work, we demonstrated a simple and environmentally-benign method to fabricate the nanostructures utilizing an electrolyte containing CuSO4·5H2O, EDTA-2Na and CH3CSNH2. The superhydrophobicity was achieved by drying thoroughly at 200 °C, instead of using low surface energy materials. After annealing at 300 °C for 6 min, the superhydrophobic surface was oxidized and became superhydrophilic. However, the superhydrophobicity can be restored by heating at 200 °C for several hours. In simpler terms, the reversible wetting transition is responded to the temperature. Scanning electron microscopy, X-ray diffractometer, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy were employed to characterize the surfaces and analyze the wetting transition mechanism. Furthermore, different kinds of oily sewages were separated by as-prepared mesh with high separation efficiency. It is believed that this method should have a promising future in expanding the applications of copper alloys.

Viscosity studies of water based magnetite nanofluids

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

Anu, K.; Hemalatha, J.

2016-05-23

Magnetite nanofluids of various concentrations have been synthesized through co-precipitation method. The structural and topographical studies made with the X-Ray Diffractometer and Atomic Force Microscope are presented in this paper. The density and viscosity studies for the ferrofluids of various concentrations have been made at room temperature. The experimental viscosities are compared with theoretical values obtained from Einstein, Batchelor and Wang models. An attempt to modify the Rosensweig model is made and the modified Rosensweig equation is reported. In addition, new empirical correlation is also proposed for predicting viscosity of ferrofluid at various concentrations.

U-PuO2, U-PuC, U-PuN cermet fuel for fast reactor

NASA Astrophysics Data System (ADS)

Mishra, Sudhir; Kaity, Santu; Banerjee, Joydipta; Nandi, Chiranjeet; Dey, G. K.; Khan, K. B.

2018-02-01

Cermet fuel combines beneficial properties of both ceramic and metal and attracts global interest for research as a candidate fuel for nuclear reactors. In the present study, U matrix PuC/PuN/PuO2 cermet for fast reactor have been fabricated on laboratory scale by the powder metallurgy route. Characterization of the fuel has been carried out using Dilatometer, Differential Thermal analysis (DTA), X-ray diffractometer and Optical microscope. X ray diffraction study of the fuel reveals presence of different phases. The PuN dispersed cermet was observed to have high solidus temperature as compared to PuC and PuO2 dispersed cermet. Swelling was observed in U matrix PuO2 cermet which also showed higher thermal expansion. Among the three cermets studied, U matrix PuC cermet showed maximum thermal conductivity.

Structural analysis of polymer thin films using GISAXS in the tender X-ray region: Concept and design of GISAXS experiments using the tender X-ray energy at BL-15A2 at the Photon Factory

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

Takagi, H., E-mail: takagih@post.kek.jp; Igarashi, N.; Mori, T.

If small angle X-ray scattering (SAXS) utilizing the soft X-ray region is available, advanced and unique experiments, which differ from traditional SAXS methods, can be realized. For example, grazing-incidence small angle X-ray scattering (GISAXS) using hard X-ray is a powerful tool for understanding the nanostructure in both vertical and lateral directions of thin films, while GISAXS utilizing the tender X-ray region (SX-GISAXS) enables depth-resolved analysis as well as a standard GISAXS analysis in thin films. Thus, at BL-15A2 at the Photon Factory, a dedicated diffractometer for SX-GISAXS (above 2.1 keV) was constructed. This diffractometer is composed of four vacuum chambers andmore » can be converted into the vacuum state from the sample chamber in front of the detector surface. Diffractions are clearly observed until 12th peak when measuring collagen by SAXS with an X-ray energy of 2.40 keV and a camera length of 825 mm. Additionally, we conducted the model experiment using SX-GISAXS with an X-ray energy of 2.40 keV to confirm that a poly(methyl methacrylate)-poly(n-butyl acrylate) block copolymer thin film has a microphase-separated structure in the thin film, which is composed of lamellae aligned both parallel and perpendicular to the substrate surface. Similarly, in a polystyrene-poly(methyl methacrylate) block copolymer thin film, SX-GISAXS with 3.60 keV and 5.73 keV revealed that hexagonally packed cylinders are aligned parallel to the substrate surface. The incident angle dependence of the first order peak position of the q{sub z} direction obtained from experiments at various incident X-ray energies agrees very well with the theoretical one calculated from the distorted wave Born approximation.« less

Measuring the x-ray resolving power of bent potassium acid phthalate diffraction crystals

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

Haugh, M. J., E-mail: haughmj@nv.doe.gov; Jacoby, K. D.; Wu, M.

2014-11-15

This report presents the results from measuring the X-ray resolving power of a curved potassium acid phthalate (KAP(001)) spectrometer crystal using two independent methods. It is part of a continuing effort to measure the fundamental diffraction properties of bent crystals that are used to study various characteristics of high temperature plasmas. Bent crystals like KAP(001) do not usually have the same diffraction properties as corresponding flat crystals. Models that do exist to calculate the effect of bending the crystal on the diffraction properties have simplifying assumptions and their accuracy limits have not been adequately determined. The type of crystals thatmore » we measured is being used in a spectrometer on the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. The first technique for measuring the crystal resolving power measures the X-ray spectral line width of the characteristic lines from several metal anodes. The second method uses a diode X-ray source and a double crystal diffractometer arrangement to measure the reflectivity curve of the KAP(001) crystal. The width of that curve is inversely proportional to the crystal resolving power. The measurement results are analyzed and discussed.« less

Measuring the x-ray resolving power of bent potassium acid phthalate diffraction crystalsa)

NASA Astrophysics Data System (ADS)

Haugh, M. J.; Wu, M.; Jacoby, K. D.; Loisel, G. P.

2014-11-01

This report presents the results from measuring the X-ray resolving power of a curved potassium acid phthalate (KAP(001)) spectrometer crystal using two independent methods. It is part of a continuing effort to measure the fundamental diffraction properties of bent crystals that are used to study various characteristics of high temperature plasmas. Bent crystals like KAP(001) do not usually have the same diffraction properties as corresponding flat crystals. Models that do exist to calculate the effect of bending the crystal on the diffraction properties have simplifying assumptions and their accuracy limits have not been adequately determined. The type of crystals that we measured is being used in a spectrometer on the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. The first technique for measuring the crystal resolving power measures the X-ray spectral line width of the characteristic lines from several metal anodes. The second method uses a diode X-ray source and a double crystal diffractometer arrangement to measure the reflectivity curve of the KAP(001) crystal. The width of that curve is inversely proportional to the crystal resolving power. The measurement results are analyzed and discussed.

Influence of Accumulative Roll Bonding on the Texture and Tensile Properties of an AZ31 Magnesium Alloy Sheets

PubMed Central

Džugan, Ján; Németh, Gergely; Lukáč, Pavel; Bohlen, Jan

2018-01-01

Deformation behaviour of rolled AZ31 sheets that were subjected to the accumulative roll bonding was investigated. Substantially refined microstructure of samples was achieved after the first and second pass through the rolling mill. Sheets texture was investigated using an X-ray diffractometer. Samples for tensile tests were cut either parallel or perpendicular to the rolling direction. Tensile tests were performed at temperatures ranging from room temperature up to 300 °C. Tensile plastic anisotropy, different from the anisotropy observed in AZ31 sheets by other authors, was observed. This anisotropy decreases with an increasing number of rolling passes and increasing deformation temperature. Grain refinement and texture are the crucial factors influencing the deformation behaviour. PMID:29303975

Applications of RIGAKU Dmax Rapid II micro-X-ray diffractometer in the analysis of archaeological metal objects

NASA Astrophysics Data System (ADS)

Mozgai, Viktória; Szabó, Máté; Bajnóczi, Bernadett; Weiszburg, Tamás G.; Fórizs, István; Mráv, Zsolt; Tóth, Mária

2017-04-01

During material analysis of archaeological metal objects, especially their inlays or corrosion products, not only microstructure and chemical composition, but mineralogical composition is necessary to be determined. X-ray powder diffraction (XRD) is a widely-used method to specify the mineralogical composition. However, when sampling is not or limitedly allowed due to e.g. the high value of the object, the conventional XRD analysis can hardly be used. Laboratory micro-XRD instruments provide good alternatives, like the RIGAKU Dmax Rapid II micro-X-ray diffractometer, which is a unique combination of a MicroMax-003 third generation microfocus, sealed tube X-ray generator and a curved 'image plate' detector. With this instrument it is possible to measure as small as 10 µm area in diameter on the object. Here we present case studies for the application of the micro-XRD technique in the study of archaeological metal objects. In the first case niello inlay of a Late Roman silver augur staff was analysed. Due to the high value of the object, since it is the only piece known from the Roman Empire, only non-destructive analyses were allowed. To reconstruct the preparation of the niello, SEM-EDX analysis was performed on the niello inlays to characterise their chemical composition and microstructure. Two types of niello are present: a homogeneous, silver sulphide niello (acanthite) and an inhomogeneous silver-copper sulphide niello (exsolution of acanthite and jalpaite or jalpaite and stromeyerite). The micro-X-ray diffractometer was used to verify the mineralogical composition of the niello, supposed on the base of SEM results. In the second case corrosion products of a Late Roman copper cauldron with uncertain provenance were examined, since they may hold clues about the burial conditions (pH, Eh, etc.) of the object. A layer by layer analysis was performed in cross sections of small metal samples by using electron microprobe and micro-X-ray diffractometer. The results show two corrosion zones: 1) the original (internal) surface zone of the metallic copper object was replaced by copper(I) oxide (cuprite), while 2) basic copper(II) carbonate (malachite) was deposited (externally) on the original surface. In our view these two minerals were formed during long-time burial, and protected the cauldron from further corrosion. Rarely copper(I) chloride (nantokite), basic copper(II) trihydroxychloride (atacamite/paratacamite) and basic copper(II) sulphate (brochantite) were also identified in the two corrosion zones. Their uneven distribution on the cauldron and their known formation conditions indicate, that these latter mineral phases may be the results of active corrosion, started possibly after excavation.

Diffractometric measurement of the temperature dependence of piezoelectric tensor in GMO monocrystal

NASA Astrophysics Data System (ADS)

Breczko, Teodor; Lempaszek, Andrzej

2007-04-01

Functional materials, of which an example is ferroelectric, ferroelastic monocrystal of molybdate (III) gadolinium (VI), are often used in the micro-motor operators (micro-servo motors) working in changeable environment conditions. Most frequently this change refers to temperature. That is why the important practical problem is the precise measurement of the value of piezoelectric tensor elements in dependence on the temperature of a particular monocrystal. In the presented article for this kind of measurements, the use of X-ray diffractometer has been shown. The advantage of the method presented is that, apart from precise dependence measurement between the temperature of a monocrystal and the value of piezoelectric tensor elements, it enables synchronous measurement of the value of thermal expansion tensor elements for a monocrystal.

Magnetic Properties of Rapid Cooled FeCoB Based Alloys Produced by Injection Molding

NASA Astrophysics Data System (ADS)

Nabialek, M.; Jeż, B.; Jeż, K.; Pietrusiewicz, P.; Gruszka, K.; Błoch, K.; Gondro, J.; Rzącki, J.; Abdullah, M. M. A. B.; Sandu, A. V.; Szota, M.

2018-06-01

The paper presents the results of investigations of the structure and magnetic properties of massive rapid cooled Fe50-xCo20+xB20Cu1Nb9 alloys (where x = 0, 5). Massive alloys were made using the method of injecting a liquid alloy into a copper mold. Samples were obtained in the form of 0.5 mm thick plates. The structure of the obtained samples was examined using an X-ray diffractometer equipped with a CuKα lamp. The phase composition of the alloys formed was determined using the Match program. By using Sherrer’s dependence the grain sizes of the identified crystalline phases were estimated. Using the Faraday magnetic balance, the magnetization of samples as a function of temperature in the range from room temperature to 850K was measured. Magnetization of saturation and value of the coercive field for the prepared alloys were determined on the basis of magnetic hysteresis loop measurement using the LakeShore vibration magnetometer.

Polymorphism of Alprazolam (Xanax): a review of its crystalline phases and identification, crystallographic characterization, and crystal structure of a new polymorph (form III).

PubMed

de Armas, Héctor Novoa; Peeters, Oswald M; Van den Mooter, Guy; Blaton, Norbert

2007-05-01

A new polymorphic form of Alprazolam (Xanax), 8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo-[4,3-alpha][1,4]benzodiazepine, C(17)H(13)ClN(4), has been investigated by means of X-ray powder diffraction (XRPD), single crystal X-ray diffraction, and differential scanning calorimetry (DSC). This polymorphic form (form III) was obtained during DSC experiments after the exothermic recrystallization of the melt of form I. The crystal unit cell dimensions for form III were determined from diffractometer methods. The monoclinic unit cell found for this polymorph using XRPD after indexing the powder diffractogram was confirmed by the cell parameters obtained from single crystal X-ray diffractometry on a crystal isolated from the DSC pans. The single crystal unit cell parameters are: a = 28.929(9), b = 13.844(8), c = 7.361(3) angstroms, beta = 92.82(3) degrees , V = 2944(2) angstroms(3), Z = 8, space group P2(1) (No.4), Dx = 1.393 Mg/m(3). The structure obtained from single crystal X-ray diffraction was used as initial model for Rietveld refinement on the powder diffraction data of form III. The temperature phase transformations of alprazolam were also studied using high temperature XRPD. A review of the different phases available in the Powder Diffraction File (PDF) database for this drug is described bringing some clarification and corrections. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.

Fundamental Parameters Line Profile Fitting in Laboratory Diffractometers

PubMed Central

Cheary, R. W.; Coelho, A. A.; Cline, J. P.

2004-01-01

The fundamental parameters approach to line profile fitting uses physically based models to generate the line profile shapes. Fundamental parameters profile fitting (FPPF) has been used to synthesize and fit data from both parallel beam and divergent beam diffractometers. The refined parameters are determined by the diffractometer configuration. In a divergent beam diffractometer these include the angular aperture of the divergence slit, the width and axial length of the receiving slit, the angular apertures of the axial Soller slits, the length and projected width of the x-ray source, the absorption coefficient and axial length of the sample. In a parallel beam system the principal parameters are the angular aperture of the equatorial analyser/Soller slits and the angular apertures of the axial Soller slits. The presence of a monochromator in the beam path is normally accommodated by modifying the wavelength spectrum and/or by changing one or more of the axial divergence parameters. Flat analyzer crystals have been incorporated into FPPF as a Lorentzian shaped angular acceptance function. One of the intrinsic benefits of the fundamental parameters approach is its adaptability any laboratory diffractometer. Good fits can normally be obtained over the whole 20 range without refinement using the known properties of the diffractometer, such as the slit sizes and diffractometer radius, and emission profile. PMID:27366594

Characterization and Selection of Polymer Materials for Binary Munitions Storage. Part 3. Branch Content Determination.

DTIC Science & Technology

1987-09-01

accuracy. The data aquisition system combines a position- sensitive X-ray detector with a 65 kilobyte microcomputer capable of operating as a...The rapid X-ray diffraction system measures intensity versus 20 patterns by placing the detector with its sensitivity axis positioned parallel to the...plane of the diffractometer (see Figure 2). As shown in Figure 2, the detector sensitivity axis z is coplanar with both the incident beam and the

Protein structural dynamics in solution unveiled via 100-ps time-resolved x-ray scattering

PubMed Central

Anfinrud, Philip

2010-01-01

We have developed a time-resolved x-ray scattering diffractometer capable of probing structural dynamics of proteins in solution with 100-ps time resolution. This diffractometer, developed on the ID14B BioCARS (Consortium for Advanced Radiation Sources) beamline at the Advanced Photon Source, records x-ray scattering snapshots over a broad range of q spanning 0.02–2.5 Å-1, thereby providing simultaneous coverage of the small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS) regions. To demonstrate its capabilities, we have tracked structural changes in myoglobin as it undergoes a photolysis-induced transition from its carbon monoxy form (MbCO) to its deoxy form (Mb). Though the differences between the MbCO and Mb crystal structures are small (rmsd < 0.2 Å), time-resolved x-ray scattering differences recorded over 8 decades of time from 100 ps to 10 ms are rich in structure, illustrating the sensitivity of this technique. A strong, negative-going feature in the SAXS region appears promptly and corresponds to a sudden > 22 Å3 volume expansion of the protein. The ensuing conformational relaxation causes the protein to contract to a volume ∼2 Å3 larger than MbCO within ∼10 ns. On the timescale for CO escape from the primary docking site, another change in the SAXS/WAXS fingerprint appears, demonstrating sensitivity to the location of the dissociated CO. Global analysis of the SAXS/WAXS patterns recovered time-independent scattering fingerprints for four intermediate states of Mb. These SAXS/WAXS fingerprints provide stringent constraints for putative models of conformational states and structural transitions between them. PMID:20406909

Protein structural dynamics in solution unveiled via 100-ps time-resolved x-ray scattering.

PubMed

Cho, Hyun Sun; Dashdorj, Naranbaatar; Schotte, Friedrich; Graber, Timothy; Henning, Robert; Anfinrud, Philip

2010-04-20

We have developed a time-resolved x-ray scattering diffractometer capable of probing structural dynamics of proteins in solution with 100-ps time resolution. This diffractometer, developed on the ID14B BioCARS (Consortium for Advanced Radiation Sources) beamline at the Advanced Photon Source, records x-ray scattering snapshots over a broad range of q spanning 0.02-2.5 A(-1), thereby providing simultaneous coverage of the small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS) regions. To demonstrate its capabilities, we have tracked structural changes in myoglobin as it undergoes a photolysis-induced transition from its carbon monoxy form (MbCO) to its deoxy form (Mb). Though the differences between the MbCO and Mb crystal structures are small (rmsd < 0.2 A), time-resolved x-ray scattering differences recorded over 8 decades of time from 100 ps to 10 ms are rich in structure, illustrating the sensitivity of this technique. A strong, negative-going feature in the SAXS region appears promptly and corresponds to a sudden > 22 A(3) volume expansion of the protein. The ensuing conformational relaxation causes the protein to contract to a volume approximately 2 A(3) larger than MbCO within approximately 10 ns. On the timescale for CO escape from the primary docking site, another change in the SAXS/WAXS fingerprint appears, demonstrating sensitivity to the location of the dissociated CO. Global analysis of the SAXS/WAXS patterns recovered time-independent scattering fingerprints for four intermediate states of Mb. These SAXS/WAXS fingerprints provide stringent constraints for putative models of conformational states and structural transitions between them.

Grain Refinement by Authigenic Inoculation Inherited from the Medium-Range Order Structure of Ni-Cr-W Superalloy

NASA Astrophysics Data System (ADS)

Gao, Zhongtang; Hu, Rui; Guo, Wei; Zhang, Chuanwei

2018-04-01

The combination of liquidus casting and thermal control solidification furnace was applied to obtain a fine-grained ingot. A rapid quenching method and x-ray diffraction measurement were used to investigate the effect of authigenic inoculation on grain refinement. The structure factor S(Q) of liquid Ni-Cr-W superalloy at 1400 °C (Liquidus temperature) and bright-field image of the microstructures quenched from 1400 °C have been measured by the high-temperature x-ray diffractometer and the transmission electron microscopy (TEM), respectively. The results show that a pre-peak exists on a S(Q) curve at the liquidus temperature. The clusters of atom in rapidly quenched microstructures obtained by isothermal heat treatment at 1400 °C were studied using TEM. Meanwhile, the effect of isothermal different temperatures on rapidly quenched microstructures was studied. The results also show that there are only the globular, equiaxed grains distributed in the solidification structure. These particles are inherited from the medium-range order structure, which is beneficial for grain refinement. The normalized work-hardening rate-strain curve indicates the work-hardening rate of fine grain is higher than that of conventional grain at the same temperature and the same deformation.

Grain Refinement by Authigenic Inoculation Inherited from the Medium-Range Order Structure of Ni-Cr-W Superalloy

NASA Astrophysics Data System (ADS)

Gao, Zhongtang; Hu, Rui; Guo, Wei; Zhang, Chuanwei

2018-05-01

The combination of liquidus casting and thermal control solidification furnace was applied to obtain a fine-grained ingot. A rapid quenching method and x-ray diffraction measurement were used to investigate the effect of authigenic inoculation on grain refinement. The structure factor S( Q) of liquid Ni -Cr-W superalloy at 1400 °C (Liquidus temperature) and bright-field image of the microstructures quenched from 1400 °C have been measured by the high-temperature x-ray diffractometer and the transmission electron microscopy (TEM), respectively. The results show that a pre-peak exists on a S( Q) curve at the liquidus temperature. The clusters of atom in rapidly quenched microstructures obtained by isothermal heat treatment at 1400 °C were studied using TEM. Meanwhile, the effect of isothermal different temperatures on rapidly quenched microstructures was studied. The results also show that there are only the globular, equiaxed grains distributed in the solidification structure. These particles are inherited from the medium-range order structure, which is beneficial for grain refinement. The normalized work-hardening rate-strain curve indicates the work-hardening rate of fine grain is higher than that of conventional grain at the same temperature and the same deformation.

Thermal etching rate of GaN during MOCVD growth interruption in hydrogen and ammonia ambient determined by AlGaN/GaN superlattice structures

NASA Astrophysics Data System (ADS)

Zhang, Feng; Ikeda, Masao; Zhang, Shuming; Liu, Jianping; Tian, Aiqin; Wen, Pengyan; Cheng, Yang; Yang, Hui

2017-10-01

Thermal etching effect of GaN during growth interruption in the metalorganic chemical vapor deposition reactor was investigated in this paper. The thermal etching rate was determined by growing a series of AlGaN/GaN superlattice structures with fixed GaN growth temperature at 735 °C and various AlGaN growth temperature changing from 900 °C to 1007 °C. It was observed that the GaN layer was etched off during the growth interruption when the growth temperature ramped up to AlGaN growth temperature. The etching thickness was determined by high resolution X-ray diffractometer and the etching rate was deduced accordingly. An activation energy of 2.53 eV was obtained for the thermal etching process.

Characterization of Micro-arc Oxidation Coatings on 6N01 Aluminum Alloy Under Different Electrolyte Temperature Control Modes

NASA Astrophysics Data System (ADS)

Wang, Xuefei; Zhu, Zongtao; Li, Yuanxing; Chen, Hui

2018-03-01

The micro-arc oxidation coatings of 6N01 aluminum alloy produced under different control modes of the electrolyte temperature are discussed in detail. Compared to those coated by a thermostatically controlled treatment, the coatings had different surface characterizations when they were coated without controlling the electrolyte temperature, particularly after treatment involving boiling electrolytes. Scanning electron microscopy and confocal laser scanning microscopy were used to observe the morphology of the coatings. Energy-dispersive spectrometry and x-ray diffractometer were used to characterize their elemental and crystalline phase compositions. The results indicate that the treatment without a controlled electrolyte temperature ultimately led to a thicker and rougher film with a respectably thick inner barrier film, a lower content of γ-Al2O3 and better corrosion resistance.

Influence of palmitic acid and hexadecanol on the phase transition temperature and molecular packing of dipalmitoylphosphatidyl-choline monolayers at the air-water interface

NASA Astrophysics Data System (ADS)

Lee, Ka Yee C.; Gopal, Ajaykumar; von Nahmen, Anja; Zasadzinski, Joseph A.; Majewski, Jaroslaw; Smith, Gregory S.; Howes, Paul B.; Kjaer, Kristian

2002-01-01

Palmitic acid (PA) and 1-hexadecanol (HD) strongly affect the phase transition temperature and molecular packing of dipalmitoylphosphatidylcholine (DPPC) monolayers at the air-water interface. The phase behavior and morphology of mixed DPPC/PA as well as DPPC/HD monolayers were determined by pressure-area-isotherms and fluorescence microscopy. The molecular organization was probed by synchrotron grazing incidence x-ray diffraction using a liquid surface diffractometer. Addition of PA or HD to DPPC monolayers increases the temperature of the liquid-expanded to condensed phase transition. X-ray diffraction shows that DPPC forms mixed crystals both with PA and HD over a wide range of mixing ratios. At a surface pressure (π) of 40 mN/m, increasing the amount of the single chain surfactant leads to a reduction in tilt angle of the aliphatic chains from nearly 30° for pure DPPC to almost 0° in a 1:1 molar ratio of DPPC and PA or HD. At this composition we also find closest packing of the aliphatic chains. Further increase of the amount of PA or HD does not change the lattice or the tilt.

Synthesis, characterization, and photocatalytic properties of nanocrystalline NZO thin films

NASA Astrophysics Data System (ADS)

Aryanto, D.; Hastuti, E.; Husniya, N.; Sudiro, T.; Nuryadin, B. W.

2018-03-01

Nanocrystalline Ni-doped ZnO (NZO) thin films were synthesized on glass substrate using sol-gel spin coating methods. The effect of annealing on the structural and optical properties of nanocrystalline thin film was studied using X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), UV-VIS spectrophotometry, and photoluminescence (PL). The results showed that the annealing temperature strongly influenced the physical properties of nanocrystalline NZO thin films. The photocatalytic properties of nanocrystalline NZO thin films were evaluated using an aqueous solution of Rhodamine-B. The photocatalytic activity of nanocrystalline NZO thin films increased with the increase of annealing temperature. The results indicated that the structure, morphology, and band gap energy of nanocrystalline NZO thin films played an important role in photocatalytic activity.

The Optics and Alignment of the Divergent Beam Laboratory X-ray Powder Diffractometer and its Calibration Using NIST Standard Reference Materials.

PubMed

Cline, James P; Mendenhall, Marcus H; Black, David; Windover, Donald; Henins, Albert

2015-01-01

The laboratory X-ray powder diffractometer is one of the primary analytical tools in materials science. It is applicable to nearly any crystalline material, and with advanced data analysis methods, it can provide a wealth of information concerning sample character. Data from these machines, however, are beset by a complex aberration function that can be addressed through calibration with the use of NIST Standard Reference Materials (SRMs). Laboratory diffractometers can be set up in a range of optical geometries; considered herein are those of Bragg-Brentano divergent beam configuration using both incident and diffracted beam monochromators. We review the origin of the various aberrations affecting instruments of this geometry and the methods developed at NIST to align these machines in a first principles context. Data analysis methods are considered as being in two distinct categories: those that use empirical methods to parameterize the nature of the data for subsequent analysis, and those that use model functions to link the observation directly to a specific aspect of the experiment. We consider a multifaceted approach to instrument calibration using both the empirical and model based data analysis methods. The particular benefits of the fundamental parameters approach are reviewed.

Low-temperature high magnetic field powder x-ray diffraction setup for field-induced structural phase transition studies from 2 to 300 K and at 0 to 8-T field

NASA Astrophysics Data System (ADS)

Shahee, Aga; Sharma, Shivani; Kumar, Dhirendra; Yadav, Poonam; Bhardwaj, Preeti; Ghodke, Nandkishor; Singh, Kiran; Lalla, N. P.; Chaddah, P.

2016-10-01

A low-temperature and high magnetic field powder x-ray diffractometer (XRD) has been developed at UGC-DAE CSR (UGC: University Grant Commission, DAE: Department of Atomic Energy, and CSR: Consortium for scientific research), Indore, India. The setup has been developed around an 18 kW rotating anode x-ray source delivering Cu-Kα x-rays coming from a vertical line source. It works in a symmetric θ-2θ parallel beam geometry. It consists of a liquid helium cryostat with an 8 T split-pair Nb-Ti superconducting magnet comprising two x-ray windows each covering an angular range of 65°. This is mounted on a non-magnetic type heavy duty goniometer equipped with all necessary motions along with data collection accessories. The incident x-ray beam has been made parallel using a parabolic multilayer mirror. The scattered x-ray is detected using a NaI detector through a 0.1° acceptance solar collimator. To control the motions of the goniometer, a computer programme has been developed. The wide-angle scattering data can be collected in a range of 2°-115° of 2θ with a resolution of ˜0.1°. The whole setup is tightly shielded for the scattered x-rays using a lead hutch. The functioning of the goniometer and the artifacts arising possibly due to the effect of stray magnetic field on the goniometer motions, on the x-ray source, and on the detector have been characterized by collecting powder XRD data of a National Institute of Standards and Technology certified standard reference material LaB6 (SRM-660b) and Si powder in zero-field and in-field conditions. Occurrence of field induced structural-phase transitions has been demonstrated on various samples like Pr0.5Sr0.5MnO3, Nd0.49Sr0.51MnO3-δ and La0.175Pr0.45Ca0.375MnO3 by collecting data in zero field cool and field cool conditions.

Impurity incorporation, deposition kinetics, and microstructural evolution in sputtered Ta films

NASA Astrophysics Data System (ADS)

Whitacre, Jay Fredric

There is an increasing need to control the microstructure in thin sputtered Ta films for application as high-temperature coatings or diffusion barriers in microelectronic interconnect structures. To this end, the relationship between impurity incorporation, deposition kinetics, and microstructural evolution was examined for room-temperature low growth rate DC magnetron sputtered Ta films. Impurity levels present during deposition were controlled by pumping the chamber to various base pressures before growth. Ar pressures ranging from 2 to 20 mTorr were used to create contrasting kinetic environments in the sputter gas. This affected both the distribution of adatom kinetic energies at the substrate as well as the rate of impurity desorption from the chamber walls: at higher Ar pressures adatoms has lower kinetic energies, and there was an increase in impurity concentration. X-ray diffraction, high-resolution transmission electron microscopy (HREM), transmission electron diffraction (TED), scanning electron microscopy (SEM), secondary ion mass spectrometry (SIMS), and x-ray photoelectron. spectroscopy (XPS) were used to examine film crystallography, microstructure, and composition. A novel laboratory-based in-situ x-ray diffractometer was constructed. This new set-up allowed for the direct observation of microstructural evolution during growth. Films deposited at increasingly higher Ar pressures displayed a systematic decrease in grain size and degree of texturing, while surface morphology was found to vary from a nearly flat surface to a rough surface with several length scales of organization. In-situ x-ray results showed that the rate of texture evolution was found to be much higher in films grown using lower Ar pressures. These effects were studied in films less than 200 A thick using high resolution x-ray diffraction in conjunction with a synchrotron light source (SSRL B.L. 7-2). Films grown using higher Ar pressures (above 10 mTorr) with a pre-growth base pressure of 1 x 10--6 Torr had grains less than 10 nm in diameter and significant amorphous content Calculated radial distribution functions show a significant increase in average inter-atomic spacing in films grown using higher base pressures and Ar pressures. The amorphous content in the films was determined via comparison between ideal crystalline diffraction patterns and actual data. Thinner films grown at higher Ar pressures had relatively greater amorphous content. Real-time process control using the in-situ diffractometer was also demonstrated. The effects observed are discussed in the context of previous theories and experiments that document room-temperature sputter film growth. The changes in film microstructure observed were impurity mediated. Specifically, oxygen desorbed from the chamber walls during growth were incorporated into the film and subsequently limited grain development and texturing. A second phase consisting of amorphous Ta2O5 formed between the grain nuclei. Adatom kinetics played a role in determining surface morphology: at low Ar pressures (2 mTorr) significant adatom kinetic energies served to flattened the film surface, though impurity levels dominated grain development even in these conditions.

The effect of calcination temperature on the formation and magnetic properties of ZnMn2O4 spinel

NASA Astrophysics Data System (ADS)

Hermanto, B.; Ciswandi; Afriani, F.; Aryanto, D.; Sudiro, T.

2018-03-01

The spinel based on transition-metal oxides has a typical composition of AB2O4. In this study, the ZnMn2O4 spinel was synthesized using a powder metallurgy technique. The Zn and Mn metallic powders with an atomic ratio of 1:2 were mechanically alloyed for 3 hours in aqueous solution. The mixed powder was then calcined in a muffle furnace at elevated temperature of 400, 500 and 600 °C. The X-ray Diffractometer (XRD) was used to evaluate the formation of a ZnMn2O4 spinel structure. The magnetic properties of the sample at varying calcination temperatures were characterized by a Vibrating Sample Magnetometer (VSM). The results show that the fraction of ZnMn2O4 spinel formation increases with the increase of calcination temperature. The calcination temperature also affects the magnetic properties of the samples.

Structural and magnetic properties of Ga-substituted Co 2 ‑W hexaferrites

NASA Astrophysics Data System (ADS)

Mahmood, Sami H.; Al Sheyab, Qusai; Bsoul, Ibrahim; Mohsen, Osama; Awadallah, Ahmad

2018-05-01

Precursor powders of BaMg2-xCoxFe16O27 with (x = 0.0, 1.0, and 2.0) were prepared using high-energy ball milling, and the effects of chemical composition and sintering temperature on the structural and magnetic properties were investigated using x-ray diffractometer (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). XRD patterns of the prepared samples indicated that crystallization of pure BaW hexaferrite phase was achieved at sintering temperature of 1300{\\deg} C, while BaM and cubic spinel phase intermediate phases were obtained at lower sintering temperatures of 1100{\\deg} C and 1200{\\deg} C. SEM images revealed improvement of the crystallization of the structural phases, and growth of the particle size with increasing the sintering temperature. The magnetic data of the samples sintered at 1300{\\deg} C revealed an increase of the saturation magnetization from 59.44 emu/g to 72.56 emu/g with increasing Co concentration (x) from 0.0 to 2.0. The coercive field Hc decreased from 0.07 kOe at x = 0.0, to 0.03 kOe at x = 1.0, and then increases to 0.09 kOe at x = 2.0. The thermomagnetic curves of the samples sintered at 1300{\\deg} C confirmed the existence of the W-type phase, and revealed spin reorientation transitions above room temperature.

Martensitic transformation and phase diagram in ternary Co-V-Ga Heusler alloys

NASA Astrophysics Data System (ADS)

Xu, Xiao; Nagashima, Akihide; Nagasako, Makoto; Omori, Toshihiro; Kanomata, Takeshi; Kainuma, Ryosuke

2017-03-01

We report the martensitic transformation behavior in Co-V-Ga Heusler alloys. Thermoanalysis and thermomagnetization measurements were conducted to observe the martensitic transformation. By using a transmission electron microscope and an in situ X-ray diffractometer, martensitic transformation was found to occur from the L21 Heusler parent phase to the D022 martensite phase. Phase diagrams were determined for two pseudo-binary sections where martensitic transformation was detected. Magnetic properties, including the Curie temperatures and spontaneous magnetization of the parent phase, were also investigated. The magnetic properties showing behaviors different from those of NiMn-based alloys were found.

Electrochromic TiO2 Thin Film Prepared by Dip-Coating Technique

NASA Astrophysics Data System (ADS)

Suriani, S.; Kamisah, M. M.

2002-12-01

Titanium dioxide (TiO2) thin films were prepared by using sol-gel dip coating technique. The coating solutions were prepared by reacting titanium isopropoxide as precursors and ethanol as solvent. The films were formed on transparent ITO-coated glass by a dip coating technique and final dried at various temperatures up to 600 °C for 30 minutes. The films were characterized with the UV-Vis-NIR Spectrometer, Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD). XRD results show that the films dried at 600 °C form anatase structure. From the spectroscopic studies, the sample shows electrochromic property.

Structural and magnetic analysis of Cu, Co substituted NiFe2O4 thin films

NASA Astrophysics Data System (ADS)

Sharma, Hakikat; Bala, Kanchan; Negi, N. S.

2016-05-01

In the present work we prepared NiFe2O4, Ni0.95Cu0.05Fe2O4 and Ni0.94Cu0.05Co0.01 Fe2O4 thin films by metallo-organic decomposition method (MOD) using spin coating technique. The thin films were analyzed by X-ray diffractometer (XRD) and Atomic force microscope (AFM) for structural studies. The XRD patterns confirmed the ferrite phase of thin films. From AFM, we analyzed surface morphology, calculated grain size (GS) and root mean square roughness (RMSR). Room temperature magnetic properties were investigated by vibrating sample magnetometer (VSM).

Electrical and magnetic properties of nano-sized magnesium ferrite

NASA Astrophysics Data System (ADS)

T, Smitha; X, Sheena; J, Binu P.; Mohammed, E. M.

2015-02-01

Nano-sized magnesium ferrite was synthesized using sol-gel techniques. Structural characterization was done using X-ray diffractometer and Fourier Transform Infrared Spectrometer. Vibration Sample Magnetometer was used to record the magnetic measurements. XRD analysis reveals the prepared sample is single phasic without any impurity. Particle size calculation shows the average crystallite size of the sample is 19nm. FTIR analysis confirmed spinel structure of the prepared samples. Magnetic measurement study shows that the sample is ferromagnetic with high degree of isotropy. Hysterisis loop was traced at temperatures 100K and 300K. DC electrical resistivity measurements show semiconducting nature of the sample.

Bruker SMART X2S Benchtop System: A Means to Making X-Ray Crystallography More Mainstream in the Undergraduate Laboratory

ERIC Educational Resources Information Center

Guzei, Ilia A.; Hill, Nicholas J.; Zakai, Uzma I.

2010-01-01

Bruker SMART X2S is a portable benchtop diffractometer that requires only a 110 V outlet to operate. The instrument operation is intuitive and facile with an automation layer governing the workflow from behind the scenes. The user participation is minimal. At the end of an experiment, the instrument attempts to solve the structure automatically;…

A high-temperature neutron diffraction study of Nb 2AlC and TiNbAlC

DOE PAGES

Bentzel, Grady W.; Lane, Nina J.; Vogel, Sven C.; ...

2014-12-16

In this paper, we report on the crystal structures of Nb 2AlC and TiNbAlC actual composition (Ti 0.45,Nb 0.55) 2AlC compounds determined from Rietveld analysis of neutron diffraction patterns in the 300-1173 K temperature range. The average linear thermal expansion coefficients of a Nb 2AlC sample in the a and c directions are, respectively, 7.9(5)x10 -6 K -1 and 7.7(5)x10 -6 K -1 on one neutron diffractometer and 7.3(3)x10 -6 K -1 and 7.0(2)x10 -6 K -1 on a second diffractometer. The respective values for the (Ti 0.45,Nb 0.55) 2AlC composition - only tested on one diffractometer - are 8.5(3)x10more » -6 K -1 and 7.5(5)x10 -6 K -1. These values are relatively low compared to other MAX phases. Like other MAX phases, however, the atomic displacement parameters show that the Al atoms vibrate with higher amplitudes than the Ti and C atoms, and 1 more along the basal planes than normal to them. In addition, when the predictions of the atomic displacement parameters obtained from density functional theory are compared to the experimental results, good quantitative agreement is found for the Al atoms. In case of the Nb and C atoms, the agreement was more qualitative.« less

Synthesis and characterization of nickel oxide particulate annealed at different temperatures

NASA Astrophysics Data System (ADS)

Sharma, Khem Raj; Thakur, Shilpa; Negi, N. S.

2018-04-01

Nickel oxide has been synthesized by solution combustion technique. The nickel oxide ceramic was annealed at 600°C and 1000°C for 2 hours. Structural, electrical, dielectric and magnetic properties were analyzed which are strongly dependent upon the synthesis method. Structural properties were examined by X-ray diffractometer (XRD), which confirmed the purity and cubic phase of nickel oxide. XRD data reveals the increase in crystallite size and decrease in full width half maximum (FWHM) as the annealing temperature increases. Electrical conductivity is found to increase from 10-6 to 10-5 (Ω-1cm-1) after annealing. Dielectric constant is observed to increase from 26 to 175 when the annealing temperature is increased from 600°C to 1000°C. Low value of coercive field is found which shows weak ferromagnetic behavior of NiO. It is observed that all the properties of NiO particulate improve with increasing annealing temperature.

Crystallization behavior of polyamide-6 microcellular nanocomposites

Treesearch

Mingjun Yuan; Lih-Sheng Turng; Shaoqin Gong; Andreas Winardi

2004-09-01

The crystallization behaviors of polyamide-6 (PA-6) and its nanocomposites undergoing the microcellular injection molding process are studied using Transmission Electron Microscopy (TEM), X-ray Diffractometer (XRD), Polarized Optical Microscopy (POM), and Differential Scanning Calorimetry (DSC). The relationships among the morphology, the mechanical property of the...

The influence of post-deposition annealing on the structure, morphology and luminescence properties of pulsed laser deposited La0.5Gd1.5SiO5 doped Dy3+ thin films

NASA Astrophysics Data System (ADS)

Ogugua, Simon N.; Swart, Hendrik C.; Ntwaeaborwa, Odireleng M.

2018-04-01

The influence of post-deposition annealing on the structure, particle morphology and photoluminescence properties of dysprosium (Dy3+) doped La0.5Gd1.5SiO5 thin films grown on Si(111) substrates at different substrate temperatures using pulsed laser deposition (PLD) technique were studied. The X-ray diffractometer results showed an improved crystallinity after post-annealing. The topography and morphology of the post-annealed films were studied using atomic force microscopy and field emission scanning electron microscopy respectively. The elemental composition in the surface region of the films were analyzed using energy dispersive X-ray spectroscopy. The photoluminescence studies showed an improved luminescent after post-annealing. The cathodoluminescence properties of the films are also reported. The CIE colour coordinates calculated from the photoluminescence and cathodoluminescence data suggest that the films can have potential application in white light emitting diode (LED) and field emission display (FED) applications.

In vitro behavior of MC3T3-E1 preosteoblast with different annealing temperature titania nanotubes.

PubMed

Yu, W Q; Zhang, Y L; Jiang, X Q; Zhang, F Q

2010-10-01

Titanium oxide nanotube layers by anodization have excellent potential for dental implants because of good bone cell promotion. It is necessary to evaluate osteoblast behavior on different annealing temperature titania nanotubes for actual implant designs.  Scanning Electron Microscopy, X-Ray polycrystalline Diffractometer (XRD), X-ray photoelectron Spectroscope, and Atomic Force Microscopy (AFM) were used to characterize the different annealing temperature titania nanotubes. Confocal laser scanning microscopy, MTT, and Alizarin Red-S staining were used to evaluate the MC3T3-E1 preosteoblast behavior on different annealing temperature nanotubes.  The tubular morphology was constant when annealed at 450°C and 550°C, but collapsed when annealed at 650°C. XRD exhibited the crystal form of nanotubes after formation (amorphous), after annealing at 450°C (anatase), and after annealing at 550°C (anatase/rutile). Annealing led to the complete loss of fluorine on nanotubes at 550°C. Average surface roughness of different annealing temperature nanotubes showed no difference by AFM analysis. The proliferation and mineralization of preostoblasts cultured on anatase or anatase/rutile nanotube layers were shown to be significantly higher than smooth, amorphous nanotube layers.  Annealing can change the crystal form and composition of nanotubes. The nanotubes after annealing can promote osteoblast proliferation and mineralization in vitro. © 2010 John Wiley & Sons A/S.

Acquisition of a High-Resolution High-Intensity X-ray Diffractometer for Research and Education

DTIC Science & Technology

2015-07-20

NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 X-ray diffraction; germanium- tin alloys...is in progress for others. Comprehensive data were acquired for pseudomorphic germanium- tin alloys grown on germanium by molecular beam epitaxy...Research  100+  2000  Federal grant  Germanium‐ tin  alloys  Tech transfer  9  180  Startup company  Metallurgy  Research  5  100  Federal grant  SAXS  Total

Dissolution Rates of Allophane, FE-Containing Allophane, and Hisingerite and Implications for Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Ralston, S. J.; Hausrath, E. M.; Tschauner, O.; Rampe, E. B.; Christoffersen, R.

2018-01-01

Investigations with the CheMin Xray Diffractometer (XRD) onboard the Curiosity rover in Gale Crater demonstrate that all rock and soil samples measured to date contain approximately 15-70 weight percentage X-ray amorphous materials. The diffuse scattering hump from the X-ray amorphous materials in CheMin XRD patterns can be fit with a combination of allophane, ferrihydrite, and rhyolitic and basaltic glass. Because of the iron-rich nature of Mars' surface, Fe-rich poorly-crystalline phases, such as hisingerite, may be present in addition to allophane.

Magnetic and structural properties of CoFe 2O 4 thin films synthesized via a sol-gel process

NASA Astrophysics Data System (ADS)

dos S. Duque, J. G.; Macêdo, M. A.; Moreno, N. O.; Lopez, J. L.; Pfanes, H.-D.

2001-05-01

Using a sol-gel process having the coconut water as a precursor of organic chain, we synthesized thin films of cobalt ferrite. The films were characterized by using a SQUID magnetometer, an X-ray diffractometer, an X-ray spectrophotometer, Mössbauer spectroscopy and atomic force microscope. Co ferrite films annealed at 500°C for 2 h show grain sizes between 10 and 20 nm, grown as single-phase spinel structure and exhibit high coercivity and a moderate saturation magnetization (above 30 kOe).

The statistical kinematical theory of X-ray diffraction as applied to reciprocal-space mapping

PubMed

Nesterets; Punegov

2000-11-01

The statistical kinematical X-ray diffraction theory is developed to describe reciprocal-space maps (RSMs) from deformed crystals with defects of the structure. The general solutions for coherent and diffuse components of the scattered intensity in reciprocal space are derived. As an example, the explicit expressions for intensity distributions in the case of spherical defects and of a mosaic crystal were obtained. The theory takes into account the instrumental function of the triple-crystal diffractometer and can therefore be used for experimental data analysis.

Yttria-Stabilized Zirconia Ceramic Deposition on SS430 Ferritic Steel Grown by PLD - Pulsed Laser Deposition Method

NASA Astrophysics Data System (ADS)

Khalid Rivai, Abu; Mardiyanto; Agusutrisno; Suharyadi, Edi

2017-01-01

Development of high temperature materials are one of the key issues for the deployment of advanced nuclear reactors due to higher temperature operation. One of the candidate materials for that purpose is ceramic-coated ferritic steel that one of the functions is to be a thermal barrier coating (TBC). Thin films of YSZ (Ytrria-Stabilized Zirconia) ceramic have been deposited on a SS430 ferritic steel using Pulsed Laser Deposition (PLD) at Center For Science and Technology of Advanced Materials laboratory - National Nuclear Energy Agency of Indonesia (BATAN). The thin film was deposited with the chamber pressure range of 200-225 mTorr, the substrate temperature of 800oC, and the number of laser shots of 3×104, 6×104 and 9×104. Afterward, the samples were analyzed using Scanning Electron Microscope - Energy Dispersive X-ray Spectroscope (SEM-EDS), X-Ray Diffractometer (XRD), Atomic Force Microscope (AFM) and Vickers hardness tester. The results showed that the YSZ could homogeneously and sticky deposited on the surface of the ferritic steel. The surfaces were very smoothly formed with the surface roughness was in the range of 70 nm. Furthermore, thickness, composition of Zr4+ dan Y3+, the crystallinity, and hardness property was increased with the increasing the number of the shots.

SILAR controlled CdSe nanoparticles sensitized ZnO nanorods photoanode for solar cell application: Electrolyte effect.

PubMed

Nikam, Pratibha R; Baviskar, Prashant K; Majumder, Sutripto; Sali, Jaydeep V; Sankapal, Babasaheb R

2018-08-15

Controlled growth of different sizes of cadmium selenide (CdSe) nanoparticles over well aligned ZnO nanorods have been performed using successive ionic layer adsorption and reaction (SILAR) technique at room temperature (27 °C) in order to form nano heterostructure solar cells. Deposition of compact layer of zinc oxide (ZnO) by SILAR technique on fluorine doped tin oxide (FTO) coated glass substrate followed by growth of vertically aligned ZnO nanorods array using chemical bath deposition (CBD) at low temperature (<100 °C). Different characterization techniques viz. X-ray diffractometer, UV-Vis spectrophotometer, field emission scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy have been used to know the structural, optical, morphological and compositional properties of synthesized nano heterostructure. The photovoltaic performance of the cells with variation in SILAR cycles for CdSe and with use of different electrolytes have been recorded as J-V characteristics and the maximum conversion efficiency of 0.63% have been attained with ferro/ferri cyanide electrolyte for 12 cycles CdSe coating over 1-D ZnO nanorods. Copyright © 2018 Elsevier Inc. All rights reserved.

Impact of crystalline defects and size on X-ray line broadening: A phenomenological approach for tetragonal SnO{sub 2} nanocrystals

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

Muhammed Shafi, P.; Chandra Bose, A., E-mail: acbose@nitt.edu

2015-05-15

Nanocrystalline tin oxide (SnO{sub 2}) powders with different grain size were prepared by chemical precipitation method. The reaction was carried out by varying the period of hydrolysis and the as-prepared samples were annealed at different temperatures. The samples were characterized using X-ray powder diffractometer and transmission electron microscopy. The microstrain and crystallite size were calculated for all the samples by using Williamson-Hall (W-H) models namely, isotropic strain model (ISM), anisotropic strain model (ASM) and uniform deformation energy density model (UDEDM). The morphology and particle size were determined using TEM micrographs. The directional dependant young’s modulus was modified as an equationmore » relating elastic compliances (s{sub ij}) and Miller indices of the lattice plane (hkl) for tetragonal crystal system and also the equation for elastic compliance in terms of stiffness constants was derived. The changes in crystallite size and microstrain due to lattice defects were observed while varying the hydrolysis time and the annealing temperature. The dependence of crystallite size on lattice strain was studied. The results were correlated with the available studies on electrical properties using impedance spectroscopy.« less

Study the effect of nitrogen flow rate on tribological properties of tantalum nitride based coatings

NASA Astrophysics Data System (ADS)

Chauhan, Dharmesh B.; Chauhan, Kamlesh V.; Sonera, Akshay L.; Makwana, Nishant S.; Dave, Divyeshkumar P.; Rawal, Sushant K.

2018-05-01

Tantalum Nitride (TaN) based coatings are well-known for their high temperature stability and chemical inertness. We have studied the effect of nitrogen flow rate variation on the structural and tribological properties of TaN based coating deposited by RF magnetron sputtering process. The nitrogen flow rate was varied from 5 to 30 sccm. X-ray diffractometer (XRD) and Atomic Force Microscopy (AFM) were used to determine structure and surface topography of coating. Pin on disc tribometer was used to determine tribological properties of coating. TaN coated brass and mild steel substrates shows higher wear resistance compared to uncoated substrates of brass and mild steel.

A novel binary Pt 3Te x/C nanocatalyst for ethanol electro-oxidation

NASA Astrophysics Data System (ADS)

Huang, Meihua; Wang, Fei; Li, Lirong; Guo, Yonglang

The Pt 3Te x/C nanocatalyst was prepared and its catalytic performance for ethanol oxidation was investigated for the first time. The Pt 3Te/C nanoparticles were characterized by an X-ray diffractometer (XRD), transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy equipped with TEM (TEM-EDX). The Pt 3Te/C catalyst has a typical fcc structure of platinum alloys with the presence of Te. Its particle size is about 2.8 nm. Among the synthesized catalysts with different atomic ratios, the Pt 3Te/C catalyst has the highest anodic peak current density. The cyclic voltammograms (CV) show that the anodic peak current density for the Pt 3Te/C, commercial PtRu/C and Pt/C catalysts reaches 1002, 832 and 533 A g -1, respectively. On the current-time curve, the anodic current on the Pt 3Te/C catalyst was higher than those for the catalysts reported. So, these findings show that the Pt 3Te/C catalyst has uniform nanoparticles and the best activity among the synthesized catalysts, and it is better than commercial PtRu/C and Pt/C catalysts for ethanol oxidation at room temperature.

Ca-doped LTO using waste eggshells as Ca source to improve the discharge capacity of anode material for lithium-ion battery

NASA Astrophysics Data System (ADS)

Setiawan, D.; Subhan, A.; Saptari, S. A.

2017-07-01

The necessity of high charge-discharge capacity lithium-ion battery becomes very urgent due to its applications demand. Several researches have been done to meet the demand including Ca doping on Li4Ti5O12 for anode material of lithium-ion batteries. Ca-doped Li4Ti5O12 (LTO) in the form of Li4-xCaxTi5O12 (x = 0, 0.05, 0.075, and 0.1) have been synthesized using simple solid state reaction. The materials preparation involved waste eggshells in the form of CaCO3 as Ca source. The structure and capacity of as-prepared samples were characterized using X-Ray Diffractometer and Cyclic Voltametry. X-Ray Diffractometer characterization revealed that all amount of dopant had entered the lattice structure of LTO successfully. The crystalline sizes were obtained by using Scherrer equation. No significant differences are detected in lattice parameters (˜8.35 Å) and crystalline sizes (˜27 nm) between all samples. Cyclic Voltametry characterization shows that Li4-xCaxTi5O12 (x = 0.05) has highest charge-discharge capacity of 177.14 mAh/g and 181.92 mAh/g, respectively. Redox-potentials of samples show no significant differences with the average of 1.589 V.

Microwave processed NiMg ferrite: Studies on structural and magnetic properties

NASA Astrophysics Data System (ADS)

Chandra Babu Naidu, K.; Madhuri, W.

2016-12-01

Ferrites are magnetic semiconductors realizing an important role in electrical and electronic circuits where electrical and magnetic property coupling is required. Though ferrite materials are known for a long time, there is a large scope in the improvement of their properties (vice sintering and frequency dependence of electrical and magnetic properties) with the current technological trends. Forth coming technology is aimed at miniaturization and smart gadgets, electrical components like inductors and transformers cannot be included in integrated circuits. These components are incorporated into the circuit as surface mount devices whose fabrication involves low temperature co-firing of ceramics and microwave monolithic integrated circuits technologies. These technologies demand low temperature sinter-ability of ferrites. This article presents low temperature microwave sintered Ni-Mg ferrites of general chemical formula Ni1-xMgxFe2O4 (x=0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) for potential applications as transformer core materials. The series of ferrites are characterized using X-ray diffractometer, scanning electron microscopy, Fourier transform infrared and vibrating sample magnetometer for investigating structural, morphological and magnetic properties respectively. The initial permeability is studied with magnesium content, temperature and frequency in the temperature range of 308 K-873 K and 42 Hz-5 MHz.

Investigation of Pb doping on electrical, structural and superconducting properties of YBa2-xPbxCu3O7-δ superconductors

NASA Astrophysics Data System (ADS)

Ezzatpour, S.; Sharifzadegan, L.; Sarvari, F.; Sedghi, H.

2018-06-01

In this study the high temperature superconductor YBa2-xPbxCu3O7-δ with doping x = ,0.05,0.1,0.15 were prepared by the standard solid-state reaction method. The effect of Pb substitution on Ba site of YBCO superconducting system, structural, electrical and superconducting properties of Y-based superconductor has been investigated. The measurements of dc resisitivity were performed on all samples with four-probe method using low frequency/lowAC current (4 mA) . The superconducting temperature, Tc, were determined from the resistivity versus temperature (R-T) curves. Results show that Pb doping reduced the cirtical temperature(Tc) and superconductivity properties of our samples. The maximum and the minimum Tc were observed for the samples with x = 0.15 and x = 0.1 respectively. The structure and phase purity of samples were examined by the X-ray powder diffraction technique (XRD) performed by means of D8 Advance Bruker diffractometer with Cu kα radiation. The grain morphology of surface of the samples was analyzed by sacanning electron microscopy (SEM). XRD patterns of polycrystalline materials of composition YBa2-xPbxCu3O7-δ revealed that all prepared samples are orthorhombic. All of the peaks of YBCO and YBa2-xPbxCu3O7-δ have been used for the estimation of volume fractions of the phases and ignored the void peaks.

Characterization of Sr-substituted W-type hexagonal ferrites synthesized by sol-gel autocombustion method

NASA Astrophysics Data System (ADS)

Ahmad, Mukhtar; Grössinger, R.; Kriegisch, M.; Kubel, F.; Rana, M. U.

2013-04-01

The magnetic and microwave characterization of single phase hexaferrites of entirely new composition Ba1-xSrxCo2AlFe15O27 (x=0.2-1.0) for application in a microwave absorber, have been reported. The samples synthesized by sol-gel method were investigated by differential thermal analyzer, Fourier transform infrared spectroscope, X-ray diffractometer, field emission gun scanning electron microscope, vibrating sample magnetometer and vector network analyzer. Platelet grains exhibit well defined hexagonal shape which is a better shape for microwave absorption. M-H loops for a selected sample were measured for a temperature range of 4.2-400 K. Moreover M-H loops for all Sr-substituted samples were also measured at room temperature up to a maximum applied field of 9 T. Saturation magnetization values were calculated by the law of approach to saturation. The room temperature coercivity for all the samples is found to be a few hundred oersteds which is necessary for electromagnetic materials and makes these ferrites ideal for microwave devices, security, switching and sensing applications. The complex permittivity, permeability and reflection losses of a selected ferrite-epoxy composite were also investigated over a frequency range of 0.5-13 GHz.

Comprehensive analysis of structure and temperature, frequency and concentration-dependent dielectric properties of lithium-substituted cobalt ferrites (Li x Co1- x Fe2O4)

NASA Astrophysics Data System (ADS)

Anjum, Safia; Nisa, Mehru; Sabah, Aneeqa; Rafique, M. S.; Zia, Rehana

2017-08-01

This paper has been dedicated to the synthesis and characterization of a series of lithium-substituted cobalt ferrites Li x Co1- x Fe2O4 ( x = 0, 0.2, 0.4, 0.6, 0.8, 1). These samples have been prepared using simple ball milling machine through powder metallurgy route. The structural analysis is carried out using X-ray diffractometer and their 3D vitalization is simulated using diamond software. The frequency and temperature-dependent dielectric properties of prepared samples have been measured using inductor capacitor resistor (LCR) meter. The structural analysis confirms that all the prepared samples have inverse cubic spinel structure. It is also revealed that the crystallite size and lattice parameter decrease with the increasing concentration of lithium (Li+1) ions, it is due to the smaller ionic radii of lithium ions. The comprehensive analysis of frequency, concentration and temperature-dependent dielectric properties of prepared samples is described in this paper. It is observed that the dielectric constant and tangent loss have decreased and conductivity increased as the frequency increases. It is also revealed that the dielectric constant, tangent loss and AC conductivity increase as the concentration of lithium increases due to its lower electronegativity value. Temperature plays a vital role in enhancing the dielectric constant, tangent loss and AC conductivity because the mobility of ions increases as the temperature increases.

Nondestructive method and apparatus for imaging grains in curved surfaces of polycrystalline articles

DOEpatents

Carpenter, Donald A.

1995-01-01

A nondestructive method, and associated apparatus, are provided for determining the grain flow of the grains in a convex curved, textured polycrystalline surface. The convex, curved surface of a polycrystalline article is aligned in a horizontal x-ray diffractometer and a monochromatic, converging x-ray beam is directed onto the curved surface of the polycrystalline article so that the converging x-ray beam is diffracted by crystallographic planes of the grains in the polycrystalline article. The diffracted x-ray beam is caused to pass through a set of horizontal, parallel slits to limit the height of the beam and thereafter. The linear intensity of the diffracted x-ray is measured, using a linear position sensitive proportional counter, as a function of position in a direction orthogonal to the counter so as to generate two dimensional data. An image of the grains in the curved surface of the polycrystalline article is provided based on the two-dimensional data.

Nondestructive method and apparatus for imaging grains in curved surfaces of polycrystalline articles

DOEpatents

Carpenter, D.A.

1995-05-23

A nondestructive method, and associated apparatus, are provided for determining the grain flow of the grains in a convex curved, textured polycrystalline surface. The convex, curved surface of a polycrystalline article is aligned in a horizontal x-ray diffractometer and a monochromatic, converging x-ray beam is directed onto the curved surface of the polycrystalline article so that the converging x-ray beam is diffracted by crystallographic planes of the grains in the polycrystalline article. The diffracted x-ray beam is caused to pass through a set of horizontal, parallel slits to limit the height of the beam and thereafter. The linear intensity of the diffracted x-ray is measured, using a linear position sensitive proportional counter, as a function of position in a direction orthogonal to the counter so as to generate two dimensional data. An image of the grains in the curved surface of the polycrystalline article is provided based on the two-dimensional data. 7 Figs.

Effect of annealing temperature on physical properties of solution processed nickel oxide thin films

NASA Astrophysics Data System (ADS)

Sahoo, Pooja; Thangavel, R.

2018-05-01

In this report, NiO thin films were prepared at different annealing temperatures from nickel acetate precursor by sol-gel spin coating method. These films were characterized by different analytical techniques to obtain their structural, optical morphological and electrical properties using X-ray diffractometer (XRD), Field emission scanning electron microscopy (FESEM), UV-Vis NIR double beam spectrophotometer and Keithley 2450 source meter respectively. FESEM images clearly indicates the formation of a homogenous and porous films. Due to their porosity, they can be used in sensing applications. The optical absorption spectra elucidated that the films are highly transparent and have a suitable band gap which are in similar agreement with earlier reports. The current enhancement under illumination shows the suitability of nanostructured NiO thin films in its application in photovoltaics.

Feasibility study of ferromagnetic/ferroelectric films for enhanced microwave devices

NASA Technical Reports Server (NTRS)

Ijiri, Yumi

2005-01-01

This report summarizes exploratory work conducted to assess the feasibility of ferromagnetic/ferroelectric films for next-generation microwave devices. From literature review, it is established that while an increasing number of ferroelectric/ferromagnetic composites are being investigated, a number have transition temperatures that are too low and structures that are not robust enough for low cost, room temperature antenna arrays. On the other hand, several promising systems are identified, including the multiferroic BiFeO3 and a composite system of Ba/SrTiO3 and a related perovskite manganite. It is suggested that when the NASA pulsed laser deposition chamber is fully operational, thin films of these systems be investigated. In preparation for such work, we have reconfirmed several structural features of an existing Ba/SrTiO3 film using the x-ray diffractometer at Oberlin College.

Supercrystallization of KCl from solution irradiated by soft X-rays

NASA Astrophysics Data System (ADS)

Janavičius, A. J.; Rinkūnas, R.; Purlys, R.

2016-10-01

The X-rays influence on KCl crystallization in a saturated water solution has been investigated for the aim of comparing it with previously considered NaCl crystallization. The rate of crystallization has been measured in the drying drop in the solution activated by the irradiation. We have measured the influence of the irradiation time of the solution on the rates of KCl crystallization as well as the beginning of the crystallization processes on drying drops. For a longer irradiation time of the solution early crystallization in the drops occurs. A saturated water solution of KCl was irradiated with the diffractometer DRON-3M (Russian device) and this had a great influence on the two-step processes of crystallization. The ionization of the solution by soft X-rays can produce ions, metastable radicals in water, excited crystals' seeds and vacancies in growing crystals by Auger's effect. The X-rays generate a very fast crystallization in the drying drop.

New X-Ray Technique to Characterize Nanoscale Precipitates in Aged Aluminum Alloys

NASA Astrophysics Data System (ADS)

Sitdikov, V. D.; Murashkin, M. Yu.; Valiev, R. Z.

2017-10-01

This paper puts forward a new technique for measurement of x-ray patterns, which enables to solve the problem of identification and determination of precipitates (nanoscale phases) in metallic alloys of the matrix type. The minimum detection limit of precipitates in the matrix of the base material provided by this technique constitutes as little as 1%. The identification of precipitates in x-ray patterns and their analysis are implemented through a transmission mode with a larger radiation area, longer holding time and higher diffractometer resolution as compared to the conventional reflection mode. The presented technique has been successfully employed to identify and quantitatively describe precipitates formed in the Al alloy of the Al-Mg-Si system as a result of artificial aging. For the first time, the x-ray phase analysis has been used to identify and measure precipitates formed during the alloy artificial aging.

Single Crystal Diffractometry

NASA Astrophysics Data System (ADS)

Arndt, U. W.; Willis, B. T. M.

2009-06-01

Preface; Acknowledgements; Part I. Introduction; Part II. Diffraction Geometry; Part III. The Design of Diffractometers; Part IV. Detectors; Part V. Electronic Circuits; Part VI. The Production of the Primary Beam (X-rays); Part VII. The Production of the Primary Beam (Neutrons); Part VIII. The Background; Part IX. Systematic Errors in Measuring Relative Integrated Intensities; Part X. Procedure for Measuring Integrated Intensities; Part XI. Derivation and Accuracy of Structure Factors; Part XII. Computer Programs and On-line Control; Appendix; References; Index.

The CheMin XRD on the Mars Science Laboratory Rover Curiosity: Construction, Operation, and Quantitative Mineralogical Results from the Surface of Mars

NASA Technical Reports Server (NTRS)

Blake, David F.

2015-01-01

The Mars Science Laboratory mission was launched from Cape Canaveral, Florida on Nov. 26, 2011 and landed in Gale crater, Mars on Aug. 6, 2012. MSL's mission is to identify and characterize ancient "habitable" environments on Mars. MSL's precision landing system placed the Curiosity rover within 2 km of the center of its 20 X 6 km landing ellipse, next to Gale's central mound, a 5,000 meter high pile of laminated sediment which may contain 1 billion years of Mars history. Curiosity carries with it a full suite of analytical instruments, including the CheMin X-ray diffractometer, the first XRD flown in space. CheMin is essentially a transmission X-ray pinhole camera. A fine-focus Co source and collimator transmits a 50µm beam through a powdered sample held between X-ray transparent plastic windows. The sample holder is shaken by a piezoelectric actuator such that the powder flows like a liquid, each grain passing in random orientation through the beam over time. Forward-diffracted and fluoresced X-ray photons from the sample are detected by an X-ray sensitive Charge Coupled Device (CCD) operated in single photon counting mode. When operated in this way, both the x,y position and the energy of each photon are detected. The resulting energy-selected Co Kalpha Debye-Scherrer pattern is used to determine the identities and amounts of minerals present via Rietveld refinement, and a histogram of all X-ray events constitutes an X-ray fluorescence analysis of the sample.The key role that definitive mineralogy plays in understanding the Martian surface is a consequence of the fact that minerals are thermodynamic phases, having known and specific ranges of temperature, pressure and composition within which they are stable. More than simple compositional analysis, definitive mineralogical analysis can provide information about pressure/temperature conditions of formation, past climate, water activity and the like. Definitive mineralogical analyses are necessary to establish the origin or provenance of a sample. The search for evidence of extant or extinct life on Mars will initially be a search for evidence of present or past conditions supportive of life (e.g., evidence of water), not for life itself.Results of the first 1,000 sols (Mars days) will be discussed, including the discovery of the first habitable environment on Mars.

Choice of precipitant and calcination temperature of precursor for synthesis of NiCo2O4 for control of CO-CH4 emissions from CNG vehicles.

PubMed

Trivedi, Suverna; Prasad, Ram

2018-03-01

Compressed natural gas (CNG) is most appropriate an alternative of conventional fuel for automobiles. However, emissions of carbon-monoxide and methane from such vehicles adversely affect human health and environment. Consequently, to abate emissions from CNG vehicles, development of highly efficient and inexpensive catalysts is necessary. Thus, the present work attempts to scan the effects of precipitants (Na 2 CO 3 , KOH and urea) for nickel cobaltite (NiCo 2 O 4 ) catalysts prepared by co-precipitation from nitrate solutions and calcined in a lean CO-air mixture at 400°C. The catalysts were used for oxidation of a mixture of CO and CH 4 (1:1). The catalysts were characterized by X-ray diffractometer, Brunauer-Emmett-Teller surface-area, X-ray photoelectron spectroscopy; temperature programmed reduction and Scanning electron microscopy coupled with Energy-Dispersive X-Ray Spectroscopy. The Na 2 CO 3 was adjudged as the best precipitant for production of catalyst, which completely oxidized CO-CH 4 mixture at the lowest temperature (T 100 =350°C). Whereas, for catalyst prepared using urea, T 100 =362°C. On the other hand the conversion of CO-CH 4 mixture over the catalyst synthesized by KOH limited to 97% even beyond 400°C. Further, the effect of higher calcination temperatures of 500 and 600°C was examined for the best catalyst. The total oxidation of the mixture was attained at higher temperatures of 375 and 410°C over catalysts calcined at 500 and 600°C respectively. Thus, the best precipitant established was Na 2 CO 3 and the optimum calcination temperature of 400°C was found to synthesize the NiCo 2 O 4 catalyst for the best performance in CO-CH 4 oxidation. Copyright © 2017. Published by Elsevier B.V.

Electronic Properties and Device Applications of III-V Compound Semiconductor Native Oxides

DTIC Science & Technology

2006-03-02

MRD X-ray diffractometer with CuKa as the radiation source. The doping level in GaAs was meassured by electrochemical voltage (ECV) using an Accent... hard to prevent the gate metal from overlapping the mesa edge thus creating a parasitic leakage path to the channel42. To reduce the gate leakage

Green Synthesis of Silver Nanoparticles by using Eucalyptus Globulus Leaf Extract

NASA Astrophysics Data System (ADS)

Balamurugan, Madheswaran; Saravanan, Shanmugam

2017-12-01

A single step eco-friendly, energy efficient and economically scalable green method was employed to synthesize silver nanoparticles. In this work, the synthesis of silver nanoparticles using Eucalyptus globulus leaf extract as reducing and capping agent along with water as solvent at normal room temperature is described. Silver nanoparticles were prepared from aqueous silver nitrate solution by adding the leaf extract. The prepared nanoparticles were characterized by using UV-visible Spectrophotometer, X-ray diffractometer, High Resolution Transmission Electron Microscope (HR-TEM) and Fourier Transform Infrared Spectroscope (FTIS). X-ray diffraction studies brought to light the crystalline nature and the face centered cubic structure of the silver nanoparticles. Using HR-TEM. the nano sizes and morphology of the particles were studied. The mean sizes of the prepared silver nanoparticles ranged from 30 to 36 nm. The density of the particles was tuned by varying the molar ratio of silver nitrate. FTIS studies showed the functional group of organic molecules which were located on the surface of the silver nanoparticles. Originating from the leaf extracts, these organic molecules reduced and capped the particles.

Growth of crystals for synchrotron radiation Mössbauer investigation

NASA Astrophysics Data System (ADS)

Kotrbova, M.; Hejduk, J.; Malnev, V. V.; Seleznev, V. N.; Yagupov, S. V.; Andronova, N. V.; Chechin, A. I.; Mikhailov, A. Yu.

1991-10-01

Iron borate crystals (FeBO 3) were flux grown at the Physical Institute (Prague) and at Simferopol State University. During the crystal growth procedure the temperature regime was held constant to 0.1°C accuracy. Crystals were investigated with the help of a double crystal X-ray diffractometer DRON-2 (SiO 2(30 overline33)FeBO 3(444), MoK α 1 radiation). The rocking curve measurements were carried out in a constant magnetic field of 1kG. Most of the crystal surface has a rocking curve 10″-15″ wide. Some parts of some crystals with the area 1 × 1 mm 2 have rocking curves of 3″-4″ width and can be considered ideal.

Dip coated TiO2 nanostructured thin film: synthesis and application

NASA Astrophysics Data System (ADS)

Vanaraja, Manoj; Muthukrishnan, Karthika; Boomadevi, Shanmugam; Karn, Rakesh Kumar; Singh, Vijay; Singh, Pramod K.; Pandiyan, Krishnamoorthy

2016-02-01

TiO2 thin film was fabricated by dip coating method using titanium IV chloride as precursor and sodium carboxymethyl cellulose as thickening as well as capping agent. Structural and morphological features of TiO2 thin film were characterized by X-ray diffractometer and field emission scanning electron microscope, respectively. Crystallinity of the film was confirmed with high-intensity peak at (101) plane, and its average crystallite size was found to be 28 nm. The ethanol-sensing properties of TiO2 thin film was studied by the chemiresistive method. Furthermore, various gases were tested in order to verify the selectivity of the sensor. Among the several gases, the fabricated TiO2 sensor showed very high selectivity towards ethanol at room temperature.

Mechanical properties of Al-Cu alloy-SiC composites

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

Anggara, B. S., E-mail: anggorobs1960@yahoo.com; Handoko, E.; Soegijono, B.

The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to getmore » better quality of back to back hardness Vickers of Al-Cu alloys.« less

Structural and magnetic analysis of Cu, Co substituted NiFe{sub 2}O{sub 4} thin films

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

Sharma, Hakikat; Bala, Kanchan; Negi, N. S.

2016-05-23

In the present work we prepared NiFe{sub 2}O{sub 4}, Ni{sub 0.95}Cu{sub 0.05}Fe{sub 2}O{sub 4} and Ni{sub 0.94}Cu{sub 0.05}Co{sub 0.01} Fe{sub 2}O{sub 4} thin films by metallo-organic decomposition method (MOD) using spin coating technique. The thin films were analyzed by X-ray diffractometer (XRD) and Atomic force microscope (AFM) for structural studies. The XRD patterns confirmed the ferrite phase of thin films. From AFM, we analyzed surface morphology, calculated grain size (GS) and root mean square roughness (RMSR). Room temperature magnetic properties were investigated by vibrating sample magnetometer (VSM).

Mechanical properties of Al-Cu alloy-SiC composites

NASA Astrophysics Data System (ADS)

Anggara, B. S.; Handoko, E.; Soegijono, B.

2014-09-01

The synthesis of aluminum (Al) alloys, Al-Cu, from mixture 96.2 % Al and 3.8 % Cu has been prepared by melting process at a temperature of 1200°C. The adding 12.5 wt% up to 20 wt% of SiC on Al-Cu alloys samples has been investigated. The structure analyses were examined by X-Ray Diffractometer (XRD) and scanning electron microscope (SEM). Moreover, the morphology of Al-Cu alloys has been seen as structure in micrometer range. The hardness was measured by hardness Vickers method. According to the results, it can be assumed that the 15 wt% of SiC content is prefer content to get better quality of back to back hardness Vickers of Al-Cu alloys.

Superdiffusion of Carbon by Vacancies Irradiated with Soft X-Rays in CZ Silicon / Superdifūzija Ar Vakancēm Iestarota Ar Mīkstajiem Rentgenstariem CZ Silīcijā

NASA Astrophysics Data System (ADS)

Janavičius, A. J.; Mekys, A.; Purlys, R.; Norgėla, Ž.; Daugėla, S.; Rinkūnas, R.

2015-10-01

The soft X-ray photons absorbed in the inner K, L, M shells of Si atoms produce photoelectrons and Auger electrons, thus generating vacancies, interstitials and metastable oxygen complexes. The samples of Czochralski silicon crystals covered with 0.1 μm thickness layer of carbon have been irradiated by X-rays using different voltages of Cu anode of the Russian diffractometer DRON-3M. The influence of X-rays on the formation of point defects and vacancy complexes, and their dynamics in Cz-Si crystals have been studied by infrared absorption. We have measured and calculated dynamics of concentration of carbon and interstitial oxygen using FTIR spectroscopy at room temperature after irradiation by soft X-rays. Using transmittance measurements and nonlinear diffusion theory we have calculated densities increasing for substitutional carbon and interstitial oxygen by reactions and very fast diffusion. The superdiffusion coefficients of carbon in silicon at room temperature generated by X-rays are about hundred thousand times greater than diffusion coefficients obtained for thermodiffusion. Rezumējums: Rentgena staru fotoni, absorbēti Si atoma iekšējos slāņos, izstaro fotoelektronus un Ožē elektronus, ģenerējot vakances, starpmezglu silīcija atomus, vakanču un skābekļa kompleksus. Čohraļska silīcija kristāli, kas pārklāti ar oglekli 0.1 μm biezuma kārtā, tika apstaroti ar rentgena stariem, izmantojot krievu difraktometru DRON-3M. Oglekļa un skābekļa difūzija un koncentrāciju izmaiņa silīcijā tika izmērīta izmantojot infrasarkano staru FTIR spektroskopiju. Rentgena staru ģenerētās ļoti ātrās oglekļa difūzijas vai superdifūzijas koeficients istabas temperatūrā silīcijā ir simtiem tūkstošu reižu lielāks nekā termodifūzijas gadījumā.

On high-resolution reciprocal-space mapping with a triple-crystal diffractometer for high-energy X-rays.

PubMed

Liss, K D; Royer, A; Tschentscher, T; Suortti, P; Williams, A P

1998-03-01

High-energy X-rav diffraction by means of triple-crystal techniques is a powerful tool for investigating dislocations and strain in bulk materials. Radiation with an energy typically higher than 80 keV combines the advantage of low attenuation with high resolution at large momentum transfers. The triple-crystal diffractometer at the High Energy Beamline of the European Synchrotron Radiation Facility is described. It is shown how the transverse and longitudinal resolution depend on the choice of the crystal reflection, and how the orientation of a reciprocal-lattice distortion in an investigated sample towards the resolution element of the instrument can play an important role. This effect is demonstrated on a single crystal of silicon where a layer of macro pores reveals satellites around the Bragg reflection. The resulting longitudinal distortion can be investigated using the high transverse resolution of the instrument when choosing an appropriate reflection.

Neutron diffraction study of aqueous Laponite suspensions at the NIMROD diffractometer.

PubMed

Tudisca, V; Bruni, F; Scoppola, E; Angelini, R; Ruzicka, B; Zulian, L; Soper, A K; Ricci, M A

2014-09-01

The process of dynamical arrest, leading to formation of different arrested states such as glasses and gels, along with the closely related process of aging, is central for both basic research and technology. Here we report on a study of the time-dependent structural evolution of two aqueous Laponite clay suspensions at different weight concentrations. Neutron diffraction experiments have been performed with the near and intermediate range order diffractometer (NIMROD) that allows studies of the structure of liquids and disordered materials over a continuous length scale ranging from 1 to 300 Å, i.e., from the atomistic to the mesoscopic scales. NIMROD is presently a unique diffractometer, bridging the length scales traditionally investigated by small angle neutron scattering or small angle x-ray scattering with that accessible by traditional diffractometers for liquids. Interestingly, we have unveiled a signature of aging of both suspensions in the length scale region of NIMROD. This phenomenon, ascribed to sporadic contacts between Laponite platelets at long times, has been observed with the sample arrested as gel or as repulsive glass. Moreover, water molecules within the layers closest to Laponite platelets surface show orientational and translational order, which maps into the crystalline structure of Laponite.

Model and prediction of stress relaxation of polyurethane fiber

NASA Astrophysics Data System (ADS)

You, Gexin; Wang, Chunyan; Mei, Shuqin; Yang, Bo; Zhou, Xiuwen

2018-03-01

In this study, the effect of small strain (less than 10%) on hydrogen bond (H-bond) and crystallinity of dry-spun polyurethane fiber was investigated with fourier transform infrared spectroscopy and x-ray diffractometer, respectively. The results showed that the H-bond of hard segments hardly broke and its degree of crystallinity scarcely varied below strain of 10%. The fiber stress relaxation behavior at 25 °C under small strain was researched using dynamic mechanical analyzer. The stress relaxation modulus constitutive equation was obtained by transforming the non-linear relationship between stress and time into the linear relationship between stress and strain. The stress relaxation modulus master curve at 25 °C was established in terms of short-term stress relaxation tests at elevated temperatures (35 °C, 45 °C, 65 °C and 75 °C) according to time-temperature superposition principle (TTS) to predict long-term behavior within 353 year.

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

Sharma, Rabindar K., E-mail: rkrksharma6@gmail.com; Reddy, G. B., E-mail: rkrksharma6@gmail.com

In this report, we synthesize vertically aligned molybdenum trioxide (α−MoO{sub 3}) nanoflakes (NFs) with high aspect ratio (height/thickness >15) on the cobalt coated glass substrates by the plasma assisted sublimation process, employing Mo metal strip as a sublimation source. The effect of substrate temperature, nature of substrate as well as the geometry of the sublimation source (Mo-strip) have been investigated on the morphological, structural and optical properties of the grown NFs, keeping plasma parameters as fixed. The surface morphology, crystalline structure and optical properties of MoO{sub 3} NFs have been studied systematically by using scanning electron microscope (SEM), transmission electronmore » microscope (TEM) with selected area electron diffraction (SAED), X-ray diffractometer, and IR- spectroscopy. The experimental observations endorse that the characteristics of MoO{sub 3} NFs are strongly depend on substrate temperature, substrate nature as well as geometry of Mo-strip. All the observed results are well in consonance with each other.« less

Investigation of structural, optical and electrical properties of Co3O4 nanoparticles

NASA Astrophysics Data System (ADS)

Bhargava, Richa; Khan, Shakeel; Ahmad, Naseem; Ansari, Mohd Mohsin Nizam

2018-05-01

In the current work, we report the synthesis of Cobalt oxide (Co3O4) NPs (NPs) by co-precipitation method. The structural analysis was confirmed by using X-ray diffractometer (XRD) which shows that the Co3O4 NPs have cubic phase. The average crystallite size and the lattice parameter were calculated for Co3O4 NPs. The functional groups of the as-synthesized sample were examined by Fourier transform infrared spectroscopy (FTIR). The optical band gap of Co3O4 NPs was estimated by using UV diffuse reflectance spectroscopy and the Band gap was evaluated by using Tauc relation. The temperature dependence of dielectric constant and dielectric loss were studied over a range of temperature 50-300 °C. The DC electrical resistivity of Co3O4 NPs shows a semiconducting behaviour and the value of activation energy was calculated by using Arrhenius equation.

Effect of growth parameters on the optical properties of ZnO nanostructures grown by simple solution methods

NASA Astrophysics Data System (ADS)

Kothari, Anjana

2017-05-01

ZnO, a wide band gap semiconductor is of significant interest for a range of practical applications. One of the highly attractive features of ZnO is to grow variety of nanostructures by using low-cost techniques. In this paper, we report deposition of ZnO nanostructure rod-arrays (NRA) via low-temperature, solution-based deposition techniques such as chemical bath deposition (CBD) and microwave-assisted chemical bath deposition (MACBD). A detailed study of film deposition parameters such as variation in concentration of precursors and deposition temperature has been carried out. Compositional and structural study of the films has been done by X-ray Diffractometer to know the phase and purity of the final product. Morphological study of these structures has been carried out by Scanning Electron Microscopy. Optical study such as transmittance and diffuse reflectance of the films has been carried out as a function of growth parameters.

Koster van Groos, A F

NASA Astrophysics Data System (ADS)

Guggenheim, S.

2008-12-01

The deep-ocean environment, including the ocean floor and crust, represents one of the last scientific frontiers on earth. The surprising lack of information on the mineralogy, the geochemical processes, or the biota of the ocean floor is the result of the inability to simulate ocean-floor conditions and to study geochemical systems at these conditions. A proto-type high-pressure environmental chamber (HPEC) has been constructed for use on a transmission- mode X-ray diffractometer to study geochemical processes at the deep-ocean sediment cover and crust. The HPEC has a designed pressure range to 1000 bars and temperature range from -20 oC to 200 oC. In this chamber, a liquid (e.g., sea water) plus sample in suspension can be pressurized either by gas or liquid. A cell-pump system continuously agitates the liquid to keep particles in suspension, thereby allowing the examination of mineral phases, including clays minerals. A major feature of the HPEC is that the mineral component moves freely and can react with its environment while being illuminated by the X-ray beam. The cell-pump also allows applied gas, such as CH4 or CO2, or O2, to interact efficiently with the aqueous liquid so that the system may rapidly reach equilibrium. In addition, mixing these gases with inert gases, e.g. He or Ar, allows control of the fugacity of these gas components. The design components and how data are manipulated to remove X-ray dispersion effects caused by the liquid will be discussed, along with examples showing the effects of temperature, pressure, and salt content on smectite clay.

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

Cooke, Gary A.; Pestovich, John A.; Huber, Heinz J.

This report presents the results for solid phase characterization (SPC) of solid samples removed from tank 241-C-108 (C-108) on August 12-13,2012, using the off-riser sampler. Samples were received at the 222-S Laboratory on August 13 and were described and photographed. The SPC analyses that were performed include scanning electron microscopy (SEM) using the ASPEX(R)l scanning electron microscope, X-ray diffraction (XRD) using the Rigaku(R) 2 MiniFlex X-ray diffractometer, and polarized light microscopy (PLM) using the Nikon(R) 3 Eclipse Pol optical microscope. The SEM is equipped with an energy dispersive X-ray spectrometer (EDS) to provide chemical information. Gary A. Cooke conducted themore » SEM analysis, John A. Pestovich performed the XRD analysis, and Dr. Heinz J. Huber performed the PLM examination. The results of these analyses are presented here.« less

The preparation and hydrogen brittleness resistance of Pd71.5Cu12Si16.5 metallic glass ribbons

NASA Astrophysics Data System (ADS)

Du, Xiaoqing; Ye, Xiaoqiu; Ren, Qingbo

2017-12-01

Pd71.5Cu12Si16.5 metallic glass ribbons as wide as 10mm were prepared by splat quenching. Structure was identified with X-ray diffraction (XRD) spectrums from the conventional X-ray diffractometer and also short wavelength X-ray stress analyzer. The results confirm fully amorphous structure of the ribbons. Multiple H2 adsorption and desorption cycles under a pressure of 100kPa were carried out in the metallic glass ribbon and also pure palladium membrane for comparison. The former didn’t show any cracks after more than 10 cycles, and thermal desorption spectroscopy (TDS) measurement confirms that hydrogen was adsorbed abundantly in the metallic glass ribbon. Pd71.5Cu12Si16.5 metallic glass ribbons demonstrate excellent hydrogen brittleness resistance.

Calculation of effective penetration depth in X-ray diffraction for pharmaceutical solids.

PubMed

Liu, Jodi; Saw, Robert E; Kiang, Y-H

2010-09-01

The use of the glancing incidence X-ray diffraction configuration to depth profile surface phase transformations is of interest to pharmaceutical scientists. The Parratt equation has been used to depth profile phase changes in pharmaceutical compacts. However, it was derived to calculate 1/e penetration at glancing incident angles slightly below the critical angle of condensed matter and is, therefore, applicable to surface studies of materials such as single crystalline nanorods and metal thin films. When the depth of interest is 50-200 microm into the surface, which is typical for pharmaceutical solids, the 1/e penetration depth, or skin depth, can be directly calculated from an exponential absorption law without utilizing the Parratt equation. In this work, we developed a more relevant method to define X-ray penetration depth based on the signal detection limits of the X-ray diffractometer. Our definition of effective penetration depth was empirically verified using bilayer compacts of varying known thicknesses of mannitol and lactose.

Observation of Structure of Surfaces and Interfaces by Synchrotron X-ray Diffraction: Atomic-Scale Imaging and Time-Resolved Measurements

NASA Astrophysics Data System (ADS)

Wakabayashi, Yusuke; Shirasawa, Tetsuroh; Voegeli, Wolfgang; Takahashi, Toshio

2018-06-01

The recent developments in synchrotron optics, X-ray detectors, and data analysis algorithms have enhanced the capability of the surface X-ray diffraction technique. This technique has been used to clarify the atomic arrangement around surfaces in a non-contact and nondestructive manner. An overview of surface X-ray diffraction, from the historical development to recent topics, is presented. In the early stage of this technique, surface reconstructions of simple semiconductors or metals were studied. Currently, the surface or interface structures of complicated functional materials are examined with sub-Å resolution. As examples, the surface structure determination of organic semiconductors and of a one-dimensional structure on silicon are presented. A new frontier is time-resolved interfacial structure analysis. A recent observation of the structure and dynamics of the electric double layer of ionic liquids, and an investigation of the structural evolution in the wettability transition on a TiO2 surface that utilizes a newly designed time-resolved surface diffractometer, are presented.

Effect of heat treatment on phase composition and crystal structure of thin WSi2 films on silicon substrates

NASA Astrophysics Data System (ADS)

Biryukov, Y. P.; Dostanko, A. P.; Maltsev, A. A.; Shakhlevich, G. M.

1984-10-01

An experimental study of WSi2 films on silicon substrates with either 111 or 100 orientation was made, for the purpose of determining the effect of annealing by heat treatment on their phase composition and crystal structure. Films of 0.2 micron thickness were deposited at a rate of 0.5 nm/s on a silicon surface which was predecontaminated of SiO2 layers and adsorbate atoms by ion sputtering in one vacuum cycle. Deposition was by condensation, with the substrate held at various temperatures from 390 to 500 C, and then annealed in an argon atmosphere at various temperatures from 700 to 1000 C for 30 min. Subsequent phase analysis at room temperature was performed with a DRON-2 X-ray diffractometer, using a CuK (sub alpha)-radiation source and covering the 20 = 10 to 130 deg range of angles by the Debye-Sherer method, while the surface morphology was examined under an electron microscope.

Pyrolytic characteristics of biomass acid hydrolysis residue rich in lignin.

PubMed

Huang, Yanqin; Wei, Zhiguo; Yin, Xiuli; Wu, Chuangzhi

2012-01-01

Pyrolytic characteristics of acid hydrolysis residue (AHR) of corncob and pinewood (CAHR, WAHR) were investigated using a thermo-gravimetric analyzer (TGA) and a self-designed pyrolysis apparatus. Gasification reactivity of CAHR char was then examined using TGA and X-ray diffractometer. Result of TGA showed that thermal degradation curves of AHR descended smoothly along with temperature increasing from 150 °C to 850 °C, while a "sharp mass loss stage" for original biomass feedstock (OBF) was observed. Char yield from AHR (42.64-30.35 wt.%) was found to be much greater than that from OBF (26.4-19.15 wt.%). In addition, gasification reactivity of CAHR char was lower than that of corncob char, and there was big difference in micro-crystallite structure. It was also found that CAHR char reactivity decreased with pyrolysis temperature, but increased with pyrolysis heating rate and gasification temperature at 850-950 °C. Furthermore, CAHR char reactivity performed better under steam atmosphere than under CO2 atmosphere. Copyright © 2011 Elsevier Ltd. All rights reserved.

Removal of heavy metal Cu(II) in simulated aquaculture wastewater by modified palygorskite.

PubMed

Cao, Jia-Shun; Wang, Cheng; Fang, Fang; Lin, Jun-Xiong

2016-12-01

Palygorskite (PAL) is a good heavy metal adsorbent due to its high surface area, low cost, and environmentally compatibility. But the natural PAL has limited its adsorption capacity and selectivity. In this study, a cost-effective and readily-generated absorbent, l-threonine-modified palygorskite (L-PAL), was used and its performance for Cu(II) removal in simulated aquaculture wastewater was evaluated. After preparation, L-PAL was characterized by using Fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffractometer, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric analysis. The impacts of pH, adsorbent dosage, contact time, and initial Cu(II) concentration on the adsorption capacity of L-PAL were examined. The Cu(II) adsorption capacity on L-PAL was enhanced almost 10 times than that of raw PAL. The adsorption isotherms of Cu(II) fit the Langmuir isotherms, and the adsorption kinetics was dominated by the pseudo-second-order model. The thermodynamic parameters at four temperatures were calculated, which indicated that the adsorption was spontaneous and endothermic. The adsorption mechanism involves complexation, chelation, electrostatic attraction, and micro-precipitation. Furthermore, L-PAL is shown to have a high regeneration capacity. These results indicate that L-PAL is a cheap and promising absorbent for Cu(II) removal and hold potential to be used for aquaculture wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tunable optical properties of plasmonic Au/Al2O3 nanocomposite thin films analyzed by spectroscopic ellipsometry accounting surface characteristics.

PubMed

Jaiswal, Jyoti; Mourya, Satyendra; Malik, Gaurav; Chandra, Ramesh

2018-05-01

In the present work, we have fabricated plasmonic gold/alumina nanocomposite (Au/Al 2 O 3 NC) thin films on a glass substrate at room temperature by RF magnetron co-sputtering. The influence of the film thickness (∼10-40  nm) on the optical and other physical properties of the samples was investigated and correlated with the structural and compositional properties. The X-ray diffractometer measurement revealed the formation of Au nanoparticles with average crystallite size (5-9.2 nm) embedded in an amorphous Al 2 O 3 matrix. The energy-dispersive X ray and X-ray photoelectron spectroscopy results confirmed the formation of Au/Al 2 O 3 NC quantitatively and qualitatively and it was observed that atomic% of Au increased by increasing thickness. The optical constants of the plasmonic Au/Al 2 O 3 NC thin films were examined by variable angle spectroscopic ellipsometry in the wide spectral range of 246-1688 nm, accounting the surface characteristics in the optical stack model, and the obtained results are expected to be unique. Additionally, a thickness-dependent blueshift (631-590 nm) of surface plasmon resonance peak was observed in the absorption spectra. These findings of the plasmonic Au/Al 2 O 3 NC films may allow the design and fabrication of small, compact, and efficient devices for optoelectronic and photonic applications.

Microstructure, ferromagnetic and photoluminescence properties of ITO and Cr doped ITO nanoparticles using solid state reaction

NASA Astrophysics Data System (ADS)

Babu, S. Harinath; Kaleemulla, S.; Rao, N. Madhusudhana; Rao, G. Venugopal; Krishnamoorthi, C.

2016-11-01

Indium-tin-oxide (ITO) (In0.95Sn0.05)2O3 and Cr doped indium-tin-oxide (In0.90Sn0.05Cr0.05)2O3 nanoparticles were prepared using simple low cost solid state reaction method and characterized by different techniques to study their structural, optical and magnetic properties. Microstructures, surface morphology, crystallite size of the nanoparticles were studied using X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM). From these methods it was found that the particles were about 45 nm. Chemical composition and valence states of the nanoparticles were studied using energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy (XPS). From these techniques it was observed that the elements of indium, tin, chromium and oxygen were present in the system in appropriate ratios and they were in +3, +4, +3 and -2 oxidation states. Raman studies confirmed that the nanoparticle were free from unintentional impurities. Two broad emission peaks were observed at 330 nm and 460 nm when excited wavelength of 300 nm. Magnetic studies were carried out at 300 K and 100 K using vibrating sample magnetometer (VSM) and found that the ITO nanoparticles were ferromagnetic at 100 K and 300 K. Where-as the room temperature ferromagnetism completely disappeared in Cr doped ITO nanoparticles at 100 K and 300 K.

Growth and studies of cyclohexylammonium 4-methoxy benzoate single crystal for nonlinear optical applications

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

Sathya, P.; Gopalakrishnan, R., E-mail: krgkrishnan@annauniv.edu

2015-06-24

Cyclohexylammonium 4-Methoxy Benzoate (C4MB) was synthesised and the functional groups were confirmed by FTIR analysis. The purified C4MB (by repeated recrystallisation) was used for single crystal growth. Single crystal of cyclohexylammonium 4-methoxy benzoate was successfully grown by slow evaporation solution growth method at ambient temperature. Structural orientations were determined from single crystal X-ray diffractometer. Optical absorption and cut off wavelength were identified by UV-Visible spectroscopy. Thermal stability of the crystal was studied from thermogravimetric and differential thermal analyses curves. Mechanical stability of the grown crystal was analysed by Vicker’s microhardness tester. The Second Harmonic Generation (SHG) study revealed that themore » C4MB compound exhibits the SHG efficiency 3.3 times greater than KDP crystal.« less

Growth and characterization of thin Cu-phthalocyanine films on MgO(001) layer for organic light-emitting diodes

PubMed Central

2012-01-01

Surface morphology and thermal stability of Cu-phthalocyanine (CuPc) films grown on an epitaxially grown MgO(001) layer were investigated by using atomic force microscope and X-ray diffractometer. The (002) textured β phase of CuPc films were prepared at room temperature beyond the epitaxial MgO/Fe/MgO(001) buffer layer by the vacuum deposition technique. The CuPc structure remained stable even after post-annealing at 350°C for 1 h under vacuum, which is an important advantage of device fabrication. In order to improve the device performance, we investigated also current-voltage-luminescence characteristics for the new top-emitting organic light-emitting diodes with different thicknesses of CuPc layer. PMID:23181826

Growth and characterization of thin Cu-phthalocyanine films on MgO(001) layer for organic light-emitting diodes.

PubMed

Bae, Yu Jeong; Lee, Nyun Jong; Kim, Tae Hee; Cho, Hyunduck; Lee, Changhee; Fleet, Luke; Hirohata, Atsufumi

2012-11-26

Surface morphology and thermal stability of Cu-phthalocyanine (CuPc) films grown on an epitaxially grown MgO(001) layer were investigated by using atomic force microscope and X-ray diffractometer. The (002) textured β phase of CuPc films were prepared at room temperature beyond the epitaxial MgO/Fe/MgO(001) buffer layer by the vacuum deposition technique. The CuPc structure remained stable even after post-annealing at 350°C for 1 h under vacuum, which is an important advantage of device fabrication. In order to improve the device performance, we investigated also current-voltage-luminescence characteristics for the new top-emitting organic light-emitting diodes with different thicknesses of CuPc layer.

Solid state parameters, structure elucidation, High Resolution X-Ray Diffraction (HRXRD), phase matching, thermal and impedance analysis on L-Proline trichloroacetate (L-PTCA) NLO single crystals.

PubMed

Kalaiselvi, P; Raj, S Alfred Cecil; Jagannathan, K; Vijayan, N; Bhagavannarayana, G; Kalainathan, S

2014-11-11

Nonlinear optical single crystal of L-Proline trichloroacetate (L-PTCA) was successfully grown by Slow Evaporation Solution Technique (SEST). The grown crystals were subjected to single crystal X-ray diffraction analysis to confirm the structure. From the single crystal XRD data, solid state parameters were determined for the grown crystal. The crystalline perfection has been evaluated using high resolution X-ray diffractometer. The frequencies of various functional groups were identified from FTIR spectral analysis. The percentage of transmittance was obtained from UV Visible spectral analysis. TGA-DSC measurements indicate the thermal stability of the crystal. The dielectric constant, dielectric loss and ac conductivity were measured by the impedance analyzer. The DC conductivity was calculated by the cole-cole plot method. Copyright © 2014 Elsevier B.V. All rights reserved.

X-ray investigations related to the shock history of the Shergotty achondrite

NASA Technical Reports Server (NTRS)

Horz, F.; Hanss, R.; Serna, C.

1986-01-01

The shock stress suffered by naturally shocked materials from the Shergotty achondrite was studied using X-ray diffraction techniques and experimentally shocked augite and enstatite as standards. The Shergotty pyroxenes revealed the formation of continuous diffraction rings, line broadening, preferred orientation of small scale diffraction domains, and other evidence of substantial lattice disorders. As disclosed by the application of Debye-Scherrer techniques, they are hybrids between single crystals and fine-grained random powders. The pyroxene lattice is very resistant to shock damage on smaller scales. While measurable lattice disaggregation and progressive fragmentation occur below 25 GPa, little additional damage is suffered from application of pressures between 30 to 60 GPa, making pressure calibration of naturally shocked pyroxenes via X-ray methods difficult. Powder diffractometer scans on pure maskelynite fractions of Shergotty revealed small amounts of still coherently diffracting plagioclase, which may contribute to the high refractive indices of the diaplectic feldspar glasses of Shergotty.

Mineralogical Changes in a Predominantly Fluviolacustrine Succession at Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Ming, D. W.; Grotzinger. J. P.; Bristow, T. F.; Blake, D. F.; Vaniman, D. T.; Chipera, S. J.; Gellert, R.; Morris, R. V.; Morrison, S. M.

2017-01-01

The Mars Science Laboratory Curiosity rover landed in Gale crater in August 2012 to investigate the strata of lower Aeolis Mons (i.e., Mount Sharp) and characterize their depositional and diagenetic environments. Visible/short-wave infrared spectra from orbit of these strata show variations in phyllosilicate, sulfate, and Fe-oxide minerals, suggesting these units record environmental changes that occurred during the early Hesperian. Curiosity has traversed over 15 km and has climbed through Approx. 200 m of stratigraphic section, made up of predominantly fluviolacustrine (i.e., the Bradbury group and the Murray formation) and aeolian (i.e., the Stimson formation) units. Multiple geochemical and mineralogical instruments are onboard Curiosity to study these ancient rocks, including the Chemistry and Mineralogy (CheMin) instrument, which is an X-ray diffractometer (XRD) and X-ray fluorescence spectrometer, and the Alpha Particle X-ray Spectrometer (APXS).

Bulk Crystal Growth, and High-Resolution X-ray Diffraction Results of LiZnAs Semiconductor Material

NASA Astrophysics Data System (ADS)

Montag, Benjamin W.; Reichenberger, Michael A.; Sunder, Madhana; Ugorowski, Philip B.; Nelson, Kyle A.; Henson, Luke C.; McGregor, Douglas S.

2017-08-01

LiZnAs is being explored as a candidate for solid-state neutron detectors. The compact form, solid-state device would have greater efficiency than present day gas-filled 3He and 10BF3 detectors. Devices fabricated from LiZnAs having either natural Li (nominally 7.5% 6Li) or enriched 6Li (usually 95% 6Li) as constituent atoms may provide a material for compact high efficiency neutron detectors. The 6Li( n, t)4He reaction yields a total Q-value of 4.78 MeV, an energy larger than that of the 10B reaction, which can easily be identified above background radiations. LiZnAs material was synthesized by preparing equimolar portions of Li, Zn, and As sealed under vacuum (10-6 Torr) in quartz ampoules lined with boron nitride and subsequently reacted in a compounding furnace (Montag et al. in J Cryst Growth 412:103, 2015). The raw synthesized LiZnAs was purified by a static vacuum sublimation in quartz (Montag et al. in J Cryst Growth 438:99, 2016). Bulk crystalline LiZnAs ingots were grown from the purified material with a high-temperature Bridgman-style growth process described here. One of the largest LiZnAs ingots harvested was 9.6 mm in diameter and 4.2 mm in length. Samples were harvested from the ingot and were characterized for crystallinity using a Bruker AXS Inc. D8 AXS Inc. D2 CRYSO, energy dispersive x-ray diffractometer, and a Bruker AXS Inc. D8 DISCOVER, high-resolution x-ray diffractometer equipped with molybdenum radiation, Gobel mirror, four bounce germanium monochromator and a scintillation detector. The primary beam divergence was determined to be 0.004°, using a single crystal Si standard. The x-ray based characterization revealed that the samples nucleated in the (110) direction and a high-resolution open detector rocking curve recorded on the (220) LiZnAs yielded a full width at half maximum (FWHM) of 0.235°. Sectional pole figures using off-axis reflections of the (211) LiZnAs confirmed in-plane ordering, and also indicated the presence of multiple domains. The LiZnAs bulk crystals exhibited a Primitive Cubic Bravais lattice instead of the commonly reported Face-centered Cubic Bravais lattice. The lattice constant was determined to be 5.5146 ± 0.0003 Å.

Photoluminescent and Thermoluminescent Studies of Dy3+ and Eu3+ Doped Y2O3 Phosphors.

PubMed

Verma, Tarkeshwari; Agrawal, Sadhana

2018-01-01

Eu 3+ doped and Dy 3+ codoped yttrium oxide (Y 2 O 3 ) phosphors have been prepared using solid-state reaction technique (SSR). The prepared phosphors were characterized by X-ray diffractometer (XRD), energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR) techniques. Photoluminescence (PL) and Thermoluminescence (TL) properties were studied in detail. PL emission spectra were recorded for prepared phosphors under excitation wavelength 254 nm, which show a high intense peak at 613 nm for Y 2 O 3 :Dy 3+ , Eu 3+ (1:1.5 mol %) phosphor. The correlated color temperature (CCT) and CIE analysis have been performed for the synthesized phosphors. TL glow curves were recorded for Eu 3+ doped and Dy 3+ codoped phosphors to study the heating rate effect and dose response. The kinetic parameters were calculated using peak shape method for UV and γ exposures through computerized glow curve deconvolution (CGCD) technique. The phosphors show second order kinetics and activation energies varying from 5.823 × 10 - 1 to 18.608 × 10 - 1  eV.

Ternary germanides RERhGe2 (RE = Y, Gd-Ho) - New representatives of the YIrGe2 type

NASA Astrophysics Data System (ADS)

Voßwinkel, Daniel; Heletta, Lukas; Hoffmann, Rolf-Dieter; Pöttgen, Rainer

2016-11-01

The YIrGe2 type ternary germanides RERhGe2 (RE = Y, Gd-Ho) were synthesized from the elements by arc-melting and characterized by powder X-ray diffraction. The structure of DyRhGe2 was refined from single crystal X-ray diffractometer data: Immm, a = 426.49(9), b = 885.0(2), c = 1577.4(3) pm, wR2 = 0.0533, 637 F2 values, 30 variables (300 K data). The structure contains two crystallographically independent dysprosium atoms in pentagonal prismatic and hexagonal prismatic coordination. The three-dimensional [RhGe2] polyanion is stabilized through covalent Rh-Ge (243-261 pm) and Ge-Ge (245-251 pm) bonding. The close structural relationship with the slightly rhodium-poorer germanides RE5Rh4Ge10 (≡ RERh0.8Ge2) is discussed. Temperature-dependent magnetic susceptibility measurements reveal Pauli paramagnetism for YRhGe2 and Curie-Weiss paramagnetism for RERhGe2 with RE = Gd, Tb, Dy and Ho. These germanides order antiferromagnetically at TN = 7.2(5), 10.6(5), 8.1(5), and 6.4(5) K, respectively.

Facile synthesis and photocatalytic activity of ZnO/zinc titanate core-shell nanorod arrays

NASA Astrophysics Data System (ADS)

He, Ding-Chao; Fu, Qiu-Ming; Ma, Zhi-Bin; Zhao, Hong-Yang; Tu, Ya-Fang; Tian, Yu; Zhou, Di; Zheng, Guang; Lu, Hong-Bing

2018-02-01

ZnO/zinc titanate core-shell nanorod arrays (CSNRs) were successfully prepared via a simple synthesis process by combining hydrothermal synthesis and liquid phase deposition (LPD). The surface morphologies, crystalline characteristics, optical properties and surface electronic states of the ZnO/zinc titanate CSNRs were characterized by scanning electron microscope, transmission electron microscope, x-ray diffractometer, x-ray photoelectron spectroscopy, PL and ultraviolet (UV)-visible absorption spectra. By controlling the reaction time of LPD, the shell thickness could vary with the reaction time. Furthermore, the impacts of the reaction time and post-annealing temperature on the crystalline structure and chemical composition of the CSNRs were also investigated. The studies of photocatalytic activity under UV light irradiation revealed that the ZnO/zinc titanate CSNRs annealed at 700 °C with 30 min deposition exhibited the best photocatalytic activity and good stability for degradation of methylene blue. It had been found that the effective separation of photogenerated electron-hole pairs in the CSNRs led to the enhanced photocatalytic activity. Moreover, the ZnO/zinc titanate CSNRs grown on quartz glass substrate could be easily recycled for reuse with almost unchanged photocatalytic activity.

Copper diffusion in Ti Si N layers formed by inductively coupled plasma implantation

NASA Astrophysics Data System (ADS)

Ee, Y. C.; Chen, Z.; Law, S. B.; Xu, S.; Yakovlev, N. L.; Lai, M. Y.

2006-11-01

Ternary Ti-Si-N refractory barrier films of 15 nm thick was prepared by low frequency, high density, inductively coupled plasma implantation of N into TixSiy substrate. This leads to the formation of Ti-N and Si-N compounds in the ternary film. Diffusion of copper in the barrier layer after annealing treatment at various temperatures was investigated using time-of-flight secondary ion mass spectrometer (ToF-SIMS) depth profiling, X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and sheet resistance measurement. The current study found that barrier failure did not occur until 650 °C annealing for 30 min. The failure occurs by the diffusion of copper into the Ti-Si-N film to form Cu-Ti and Cu-N compounds. FESEM surface morphology and EDX show that copper compounds were formed on the ridge areas of the Ti-Si-N film. The sheet resistance verifies the diffusion of Cu into the Ti-Si-N film; there is a sudden drop in the resistance with Cu compound formation. This finding provides a simple and effective method of monitoring Cu diffusion in TiN-based diffusion barriers.

Thermal equation of state of CaFe 2O 4-type MgAl 2O 4

NASA Astrophysics Data System (ADS)

Sueda, Yuichiro; Irifune, Tetsuo; Sanehira, Takeshi; Yagi, Takehiko; Nishiyama, Norimasa; Kikegawa, Takumi; Funakoshi, Ken-ichi

2009-05-01

In situ X-ray diffraction measurements of CaFe 2O 4-type MgAl 2O 4 have been conducted at pressures up to 42 GPa and temperatures to 2400 K using Kawai-type multianvil apparatus with sintered diamond anvils. Additional measurements have also been conducted at pressures to 12 GPa using diamond anvil cell with helium as a pressure medium at room temperature, and at temperatures to 836 K at the ambient pressure using a high-temperature X-ray diffractometer. The analysis of room-temperature data yielded V0 = 240.1(2) Å 3, K0 = 205(6) GPa, and K0=4.1(3). A fit of the present data to high-temperature Birch-Murnaghan equation of state (EOS) yielded (∂ K0/∂ T) P = -0.030(2) GPa/K and α0 = a0 + b0T with values of a0 = 1.96(13) × 10 -5 K -1 and b0 = 1.64(24) × 10 -8 K -2. The present data set was also fitted to Mie-Grüneisen-Debye (MGD) EOS and we obtained γ0 = 1.73(7), q = 2.03(37), and θ0 = 1546(104) K. Density changes of MORB have been estimated using the newly obtained thermoelastic parameters, assuming that the Al-rich phase in this composition possesses the CaFe 2O 4-type structure under the lower mantle P, T conditions. The calculated densities along geotherms for the normal mantle and subducting cold slabs are both significantly higher than those of typical seismological models, confirming the conclusion of some recent results on MORB by laser-heated diamond anvil cell experiments.

Morphology, orientation, and mechanical properties of gelatin films

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

Blanton, T.N.; Tsou, A.H.

1996-12-31

Gelatin is a polypeptide derived from degradation and disorganization of collagen fibers and is the primary binder in photographic emulsions. Gelatin provides the mechanical integrity and strength to the photographic emulsion allowing for packaging, handling, and photofinishing operations. Gelatin films generated from aqueous-solution casting can exist in a semicrystalline or an amorphous state. When a gelatin solution is cooled below its helix-coil transition temperature, partial renaturation of gelatin to form triple helices can occur. The degree of renaturation in a coated film is dependent upon the drying temperature and the drying rate. During the drying process, gelatin crystals can bemore » formed by lateral association of the triple helices through a mechanism of nucleation and growth of a fringed micelle structure. X-ray scattering techniques have been utilized to examine the morphology and orientation of gelatin films. Based on X-ray diffraction data, it is observed that aggregates of triple-helix rods lie parallel to the film plane but are symmetrically distributed within the film plane. Since a material`s physical and mechanical properties are related to its structure, it is necessary to understand and to characterize the morphological development in gelatin film formation. In this study, an X-ray diffractometer and pole figure goniometer were utilized to examine the structural development and orientation anisotropy in solid-state gelatin films. Also, in this study, the in-plane mechanical properties of a gelatin film were determined from a uniaxial tensile test, and the gelatin film properties in the thickness direction were extracted from an indentation test based on the finite element analysis of the indentation results using a viscoelastic material model.« less

Size dependent structural and magnetic properties of Al substituted Co–Mg ferrites synthesized by the sol–gel auto-combustion method

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

Ahmad, Imran, E-mail: imraan77@yahoo.com; Abbas, Tahir; Ziya, A.B.

2014-04-01

Highlights: • Well-crystalline Co{sub 0.7}Mg{sub 0.3}AlFeO{sub 4} nanoparticles with small grain size were obtained. • The approach is sol–gel auto-combustion technique for obtained nanoparticles. • The prepared Co{sub 0.7}Mg{sub 0.3}AlFeO{sub 4} ferrites are decent soft materials with low coercivity. • The minor decrease in lattice parameter with increase of temperature was observed. - Abstract: Single phased nanocrystalline Co{sub 0.7}Mg{sub 0.3}FeAlO{sub 4} ferrites having low coercivity were synthesized by the sol–gel auto-combustion route. The subsequent powder materials were sintered in a temperature range of 800–1200 °C for 2 h. The effects of sintering temperatures on the structure, morphology and magnetic propertiesmore » of the prepared soft magnetic material were studied. X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and magnetic property measurement system (MPMS) were used to characterize the samples. X-ray diffraction analysis confirmed a single-phase cubic spinel structure and ruled out the presence of impurities like hematite. The higher sintering temperatures have caused in enhanced mark of crystallinity and bigger average grain size of the nanocrystals. A slight decrease in lattice parameters was noticed with a rise of grain size. Magnetic measurements revealed that grain size increase led to a decrease in the coercivity and, in difference, an increase in the saturation magnetization.« less

Acquisition of an X-Ray Diffractometer with WAXS and SAXS for Materials Research

DTIC Science & Technology

2015-03-31

2. This ligand is known as a sensitizer for applications in dye -sensitized solar cells, and the presence of the amino groups could potentially...achieve different surface properties, thus making them excellent candidates for use as fillers in bio-based biodegradable composite materials...These CNCs are environmentally safe sustainable, biodegradable , carbon neutral, and have low environmental, health and safety risks. Figure 9 below

Toward in situ x-ray diffraction imaging at the nanometer scale

NASA Astrophysics Data System (ADS)

Zatsepin, Nadia A.; Dilanian, Ruben A.; Nikulin, Andrei Y.; Gable, Brian M.; Muddle, Barry C.; Sakata, Osami

2008-08-01

We present the results of preliminary investigations determining the sensitivity and applicability of a novel x-ray diffraction based nanoscale imaging technique, including simulations and experiments. The ultimate aim of this nascent technique is non-destructive, bulk-material characterization on the nanometer scale, involving three dimensional image reconstructions of embedded nanoparticles and in situ sample characterization. The approach is insensitive to x-ray coherence, making it applicable to synchrotron and laboratory hard x-ray sources, opening the possibility of unprecedented nanometer resolution with the latter. The technique is being developed with a focus on analyzing a technologically important light metal alloy, Al-xCu (where x is 2.0-5.0 %wt). The mono- and polycrystalline samples contain crystallographically oriented, weakly diffracting Al2Cu nanoprecipitates in a sparse, spatially random dispersion within the Al matrix. By employing a triple-axis diffractometer in the non-dispersive setup we collected two-dimensional reciprocal space maps of synchrotron x-rays diffracted from the Al2Cu nanoparticles. The intensity profiles of the diffraction peaks confirmed the sensitivity of the technique to the presence and orientation of the nanoparticles. This is a fundamental step towards in situ observation of such extremely sparse, weakly diffracting nanoprecipitates embedded in light metal alloys at early stages of their growth.

Experimental and theoretical investigation of the rocking curves measured for Mo K α X-ray characteristic lines in the double-crystal nondispersive scheme

NASA Astrophysics Data System (ADS)

Marchenkov, N. V.; Chukhovskii, F. N.; Blagov, A. E.

2015-03-01

The rocking curves (RCs) for Mo K α1 h Mo K α2 characteristic X-ray lines have been experimentally and theoretically studied in the nondispersive scheme of an X-ray double-crystal TPC-K diffractometer. The results of measurements and theoretical calculations of double-crystal RCs for characteristic X-rays from tubes with a molybdenum anode and different widths of slits show that a decrease in the slit width leads to an increase in the relative contribution of the Mo K α2-line RC in comparison with the intensity of the tails of the Mo K α1-line RC. It is shown that the second peak of the Mo K α2 line becomes increasingly pronounced in the tail of the Mo K α1-line RC with a decrease in the slit width. Two plane-parallel Si plates (input faces {110}, diffraction vector h <220>) were used as a monochromator crystal and a sample. The results of measuring double-crystal RCs are in good agreement with theoretical calculations.

The enhancement in dielectric and magnetic property in Na and Mn co substituted lanthanum ferrite

NASA Astrophysics Data System (ADS)

Rai, Atma; Thakur, Awalendra K.

2016-05-01

Nanocrystalline solid solutions of La1-xNaxFe1-yMnyO3 (x=y=0.00 and 0.25) were prepared via modified Pechini route. No evidence of secondary or impurity phase has been detected up to the detection of error limit of high power X-ray diffractometer. Dielectric property of the samples has been investigated in the frequency range 100 Hz-4MHz at temperature ranging 300-450K. The value of relative permittivity (ɛr) increases drastically and shows colossal dielectric response (˜104) by cosubstitution of Na and Mn as compared to pure LaFeO3. Dielectric relaxation peak in loss tangent in both samples have been found and shift towards higher frequency region as temperature increases. Magnetization-Field (M-H) loop of the calcined sample have been recorded at room temperature (300K) at field ±60kOe. Magnetic property also enhanced by co substitution of Na and Mn. The change in Fe/Mn-O-Fe/Mn angle by co-substitution of Na and Mn in LaFeO3 and indirect exchange interaction between two different magnetic sub lattices Fe and Mn might be responsible for drastic change. Saturation/maximum magnetic moment increase ˜four times in LNFM25 (5.335emu/g) as compared to pure LaFeO3 (1.302emu/g).

Study on GaN nanostructures: Growth and the suppression of the yellow emission

NASA Astrophysics Data System (ADS)

Wang, Ting; Chen, Fei; Ji, Xiaohong; Zhang, Qinyuan

2018-07-01

GaN nanostructures were synthesized via a simple chemical vapor deposition using Ga2O3 and NH3 as precursors. Structural and morphological properties were systematically characterized by field emission scanning electron microscopy, X-ray diffractometer, transmission electron microscopy, and Raman spectroscopy. The configuration of GaN nanostructures was found to be strongly dependent on the growth temperature and the NH3 flow rate. Photoluminescence analysis revealed that all the fabricated GaN NSs exhibited a strong ultra-violet emission (∼364 nm), and the yellow emission of GaN nanorods can be suppressed at appropriate III/V ratio. The suppression of the yellow emission was attributed to the low density of surface or the VGa defect. The work demonstrates that the GaN nanostructures have potential applications in the optoelectronic and nanoelectronic devices.

Synthesis of Flexible Graphene/Polymer Composites for Supercapacitor Applications

NASA Astrophysics Data System (ADS)

Pal, Himangshu; Bhubna, Shuvam; Kumar, Praduman; Mahapatra, Rajat; Chatterjee, Somenath

2018-01-01

In this paper, the graphene was synthesized using biocompatible cellulosic component from onions. Onion epidermal cells were chosen as raw material. During heating at high temperature, the bonding among atoms in material was rearranged and forms two-dimensional hexagonal carbon layer (graphene). The characterization of synthesized graphene was done by x-ray diffractometer, Raman spectrometer and field emission scanning electron microscopy, respectively. An attempt has been taken to form the capacitors with two different current collector electrodes, anticipating the performance of the supercapacitors. The observed capacitance values as-obtained for Al and Au current collector were 1.3 μF and 6.08 μF, respectively. However, when thermally exfoliated graphene was used as an electrode on Al and Au current collector, the capacitance value was drastically increased and found to be 1.6 and 41.25 μF, respectively.

Microstructural, optical and electrical properties of LaFe0.5Cr0.5O3 perovskite nanostructures

NASA Astrophysics Data System (ADS)

Ali, S. Asad; Naseem, Swaleha; Khan, Wasi; Sharma, A.; Naqvi, A. H.

2016-05-01

Perovskite nanocrystalline powder of LaFe0.5Cr0.5O3 was synthesized by sol-gel combustion route and characterized by x-ray diffractometer (XRD), scanning electron microscopy (SEM) equipped with EDS, UV-visible and LCR meter at room temperature Rietveld refinement of the XRD data confirms that the sample is in single phase-rhombohedral structure with space group R-3C. SEM micrograph shows clear nanostructure of the sample and EDS ensures the presence of all elements in good stoichiometric. The optical absorption indicates the maximum absorption at 315 nm and optical band gap of 2.94 eV was estimated using Tauc's relation. Dielectric constant (ɛ') and loss were found to decrease with increase in frequencies. The dielectric behavior was explained on the basis of Maxwell-Wagner's two layer model.

Preparation and characterization of ultrafine nanoparticles of Cu doped lithium tetraborate

NASA Astrophysics Data System (ADS)

Khalilzadeh, Nasrin; Saion, Elias Bin; Mirabolghasemi, Hamed; Crouse, Karen A.; Shaari, Abdul Halim Bin; Hashim, Mansor Bin

This study details an innovative single-step thermal synthesis of nano-sized lithium tetraborate doped with 0.1 %wt copper and its characterization. The heating temperature for the synthesis of the nanoparticle material was optimized by variation between 200 and 850 °C. The optimum amount of polyvinyl pyrrolidone (PVP) the capping agent was determined to be 0.027 mol per 1 g LTB-Cu. The calcination time was 2 h. Characterization of the samples was carried out using Thermogravimetry Analysis (TGA), Derivative Thermogravimetry (DTG), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffractometer (XRD), transmission electron microscopy (TEM) and Ultraviolet-Visible (UV-Vis) spectroscopy. The product was thermally stable above 450 °C. FTIR, XRD and TEM results confirmed the formation of pure nano-crystalline copper doped lithium tetraborate between 450 and 750 °C. The optical bandgap was estimated to be 5.02-6.05 eV in the presence of different amounts of PVP at various calcination temperatures.

The influences of target properties and deposition times on pulsed laser deposited hydroxyapatite films

NASA Astrophysics Data System (ADS)

Bao, Quanhe; Chen, Chuanzhong; Wang, Diangang; Liu, Junming

2008-11-01

Hydroxyapatite films were produced by pulsed laser deposition from three kinds of hydroxyapatite targets and with different deposition times. A JXA-8800R electron probe microanalyzer (EPMA) with a Link ISIS300 energy spectrum analyzer was used to give the secondary electron image (SE) and determine the element composition of the films. The phases of thin film were analyzed by a D/max-γc X-ray diffractometer (XRD). The Fourier-transform infrared spectroscopy (FT-IR) was used to characterize the hydroxyl, phosphate and other functional groups. The results show that deposited films were amorphous which mainly composed of droplet-like particles and vibration of PO 43- groups. With the target sintering temperature deposition times increasing, the density of droplets is decreased. While with deposition times increasing, the density of droplets is increased. With the target sintering temperature and deposition time increasing, the ratio of Ca/P is increasing and higher than that of theoretical value of HA.

Investigations of interatomic interaction in InAs-InAs1-xSbx heterostructures on a base of x-ray diffractometry

NASA Astrophysics Data System (ADS)

Babjuck, T. I.; Buntar, A. G.; Shevtchuk, L. S.

2001-06-01

Hetero-transitions on a base of InAs and AnSb compounds permitted to obtain cheap light diodes and detectors with the atmosphere maximal transparency region sensibility. There is assumed simultaneously, that the phon radiation in InAs-InAs1-xSbx is not large, which positively effects on receiver parameters. Changing the composition of InAs-InAs1- xSbx solution, one may obtain the structure with the width of forbidden zone of the want of 0.35 to 0,1 eV. There is developed the heterostructures crystalline lattice parameters determining method (for substrate and film) with the DRON-3M x-ray diffractometer. There was found the nonlinear dependence of the heterostructures lattice parameter on the composition. Investigations of interatomic interaction in dependence on composition and also on the forbidden zone width Eg(x) have show, that solid solutions InAs-InAs1- xSbx may be used for the obtaining of infra-red receiver.

Touch-free in situ investigation of ancient Egyptian pigments.

PubMed

Uda, M; Sassa, S; Taniguchi, K; Nomura, S; Yoshimura, S; Kondo, J; Iskander, N; Zaghloul, B

2000-06-01

Some of the pigments painted on the Funerary Stele of Amenemhat (ca. 2000 B.C.) exhibited at the Egyptian Museum, Cairo and on the walls of the Tomb of Userhat (ca. 1420 B.C.), a rock-cut tomb in Thebes, Egypt, were investigated in situ using both a convenient home-made hand-held type of X-ray diffractometer and a commercial X-ray fluorescence spectrometer in a complementary way under touch-free conditions. CaCO3.3MgCO3 (huntite) was found in the white-painted parts of these two ancient monuments. An arsenic (As)-bearing phase was detected in the yellow-painted parts of the latter monument. The occurrence of huntite in Egypt has not been reported previously.

Room-temperature X-ray diffraction studies of cisplatin and carboplatin binding to His15 of HEWL after prolonged chemical exposure.

PubMed

Tanley, Simon W M; Schreurs, Antoine M M; Kroon-Batenburg, Loes M J; Helliwell, John R

2012-11-01

The anticancer complexes cisplatin and carboplatin are known to bind to both the Nδ and the Nℇ atoms of His15 of hen egg-white lysozyme (HEWL) in the presence of dimethyl sulfoxide (DMSO). However, neither binds in aqueous media after 4 d of crystallization and crystal growth, suggesting that DMSO facilitates cisplatin/carboplatin binding to the N atoms of His15 by an unknown mechanism. Crystals of HEWL cocrystallized with cisplatin in both aqueous and DMSO media, of HEWL cocrystallized with carboplatin in DMSO medium and of HEWL cocrystallized with cisplatin and N-acetylglucosamine (NAG) in DMSO medium were stored for between seven and 15 months. X-ray diffraction studies of these crystals were carried out on a Bruker APEX II home-source diffractometer at room temperature. Room-temperature X-ray diffraction data collection removed the need for cryoprotectants to be used, ruling out any effect that the cryoprotectants might have had on binding to the protein. Both cisplatin and carboplatin still bind to both the Nδ and Nℇ atoms of His15 in DMSO media as expected, but more detail for the cyclobutanedicarboxylate (CBDC) moiety of carboplatin was observed at the Nℇ binding site. However, two molecules of cisplatin were now observed to be bound to His15 in aqueous conditions. The platinum peak positions were identified using anomalous difference electron-density maps as a cross-check with Fo-Fc OMIT electron-density maps. The occupancies of each binding site were calculated using SHELXTL. These results show that over time cisplatin binds to both N atoms of His15 of HEWL in aqueous media, whereas this binding is speeded up in the presence of DMSO. The implication of cisplatin binding to proteins after a prolonged period of time is an important consideration for the length of treatment in patients who are given cisplatin.

The enhancement in dielectric and magnetic property in Na and Mn co substituted lanthanum ferrite

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

Rai, Atma, E-mail: atma@iitp.ac.in; Thakur, Awalendra K., E-mail: akt@iitp.ac.in; Centre for Energy and Environment Indian Institute of Technology Patna 800013 India

2016-05-06

Nanocrystalline solid solutions of La{sub 1-x}Na{sub x}Fe{sub 1-y}Mn{sub y}O{sub 3} (x=y=0.00 and 0.25) were prepared via modified Pechini route. No evidence of secondary or impurity phase has been detected up to the detection of error limit of high power X-ray diffractometer. Dielectric property of the samples has been investigated in the frequency range 100 Hz-4MHz at temperature ranging 300–450K. The value of relative permittivity (ε{sub r}) increases drastically and shows colossal dielectric response (∼10{sup 4}) by cosubstitution of Na and Mn as compared to pure LaFeO{sub 3}. Dielectric relaxation peak in loss tangent in both samples have been found and shiftmore » towards higher frequency region as temperature increases. Magnetization-Field (M-H) loop of the calcined sample have been recorded at room temperature (300K) at field ±60kOe. Magnetic property also enhanced by co substitution of Na and Mn. The change in Fe/Mn-O-Fe/Mn angle by co-substitution of Na and Mn in LaFeO{sub 3} and indirect exchange interaction between two different magnetic sub lattices Fe and Mn might be responsible for drastic change. Saturation/maximum magnetic moment increase ∼four times in LNFM25 (5.335emu/g) as compared to pure LaFeO{sub 3} (1.302emu/g).« less

Unusual Thermal Stability of High-Entropy Alloy Amorphous Structure

DTIC Science & Technology

2012-06-20

incident angle X - ray diffractometer (GIAXRD, RIGAKU D/MAX2500) with Cu Kα radiation and at the incident angle of 1°. The surface morphology and...microanalyzer (EPMA, JEOL JAX-8800). The crystallographic structures of as-deposited and annealed metallic films were characterized utilizing a glancing ...field image and selected-area- diffraction (SAD) patterns of (a) 800 °C-, (b) 850 °C- and (c) 900 °C-annealed alloy thin films, respectively. Both

Hydrothermal synthesis and characterization of a novel supramolecular network compound of Co(NIA) 2(H 2O) 4 with molecular ladder hydrogen bond chains (NIA=nicotinate)

NASA Astrophysics Data System (ADS)

Jia, Hong-Bin; Yu, Jie-Hui; Xu, Ji-Qing; Ye, Ling; Ding, Hong; Jing, Wei-Jie; Wang, Tie-Gang; Xu, Jia-Ning; Li, Zeng-Chun

2002-10-01

By hydrothermal method, a novel supramolecular compound, Co(NIA) 2(H 2O) 4 was synthesized and its structure was characterized with elemental analysis, FT-IR spectrum, TGA and X-ray diffractometer, indicating that it is a novel polyporous supramolecule with molecular ladder hydrogen-bonded chains. TGA curve shows its thermal stability up to 520 °C.

Effect of hydrothermal condition on the formation of multi-component oxides of Ni-based metallic glass under high temperature water near the critical point

DOE PAGES

Kim, J. S.; Kim, S. Y.; Kim, D. H.; ...

2015-07-01

The specific feature of multi-component oxides synthesized by hydrothermal process under high temperature (633 K) and highly pressurized water (18.9 MPa) near critical point. Effects of hydrothermal processing duration times 24 hours and 72 hours, respectively, on the oxide formation of the Ni 59Zr 20Ti 16Si 2Sn 3 metallic glass synthesized by powder metallurgy process were characterized by X-ray diffractometer, differential scanning calorimeter along with the particle size, morphology and crystalline phase of the oxides. The crystallization of the needle-shape NiTiO 3, ZrTiO 4 and ZrSnO 4 ternary oxide phases observed on the surface of metallic glass at below glassmore » transition temperature and the morphology of oxide phases changed to plate-shape around 2 μm in diameter by the increase processing time. This hydrothermal processing in subcritical water provides accelerated dense metal oxide crystals due to the reaction medium being at higher pressure than conventional oxidation processing.« less

Mineral carbonation of gaseous carbon dioxide using a clay-hosted cation exchange reaction.

PubMed

Kang, Il-Mo; Roh, Ki-Min

2013-01-01

The mineral carbonation method is still a challenge in practical application owing to: (1) slow reaction kinetics, (2) high reaction temperature, and (3) continuous mineral consumption. These constraints stem from the mode of supplying alkaline earth metals through mineral acidification and dissolution. Here, we attempt to mineralize gaseous carbon dioxide into calcium carbonate, using a cation exchange reaction of vermiculite (a species of expandable clay minerals). The mineralization is operated by draining NaCI solution through vermiculite powders and continuously dropping into the pool of NaOH solution with CO2 gas injected. The mineralization temperature is regulated here at 293 and 333 K for 15 min. As a result of characterization, using an X-ray powder diffractometer and a scanning electron microscopy, two types of pure CaCO3 polymorphs (vaterite and calcite) are identified as main reaction products. Their abundance and morphology are heavily dependent on the mineralization temperature. Noticeably, spindle-shaped vaterite, which is quite different from a typical vaterite morphology (polycrystalline spherulite), forms predominantly at 333 K (approximately 98 wt%).

Synthesis, characterization and color performance of novel Co²+-doped alumina/titania nanoceramic pigments.

PubMed

Hafez, Hoda S; El-Fadaly, E

2012-09-01

Blue-green nanoceramic pigments from Co(2+)-doped alumina-titania (xCo(2+)-Al(2)O(3)/TiO(2)) have been synthesized by alkoxide sol-gel route from a mixture of titania and boehmite sols that derived from titanium isopropoxide and aluminum nitrate precursors. The composition of the alumina/titania (AT) matrix is 3:1M ratio. A series of xCo(2+):3TiO(2):1Al(2)O(3) mixed oxides with different Co(2+)-dopant ion concentration has been prepared. The molar ratio of the Co(2+)-dopant ion in the Al(2)O(3)/TiO(2) matrix is from x=0 to 0.5M ratio relative to the titania composition. Characterizations of Co(2+)-doped alumina/titania nanocomposites are carried out using reflectance spectroscopy, transmission electron microscope (TEM), scanning electron microscopy (SEM-EDS), thermo-gravimetric analysis (TGA) and X-ray diffractometer (XRD). The experimental results demonstrated that the prepared Co(2+)-doped alumina-titania nanocomposites fulfill the current technological requirements for ceramic pigment applications that exhibit a high physico-chemical and thermal stabilities at high firing temperatures. Copyright © 2012 Elsevier B.V. All rights reserved.

X-ray scattering signatures of β-thalassemia

NASA Astrophysics Data System (ADS)

Desouky, Omar S.; Elshemey, Wael M.; Selim, Nabila S.

2009-08-01

X-ray scattering from lyophilized proteins or protein-rich samples is characterized by the presence of two characteristic broad peaks at scattering angles equivalent to momentum transfer values of 0.27 and 0.6 nm -1, respectively. These peaks arise from the interference of coherently scattered photons. Once the conformation of a protein is changed, these two peaks reflect such change with considerable sensitivity. The present work examines the possibility of characterizing the most common cause of hemolytic anaemia in Egypt and many Mediterranean countries; β-thalassemia, from its X-ray scattering profile. This disease emerges from a genetic defect causing reduced rate in the synthesis of one of the globin chains that make up hemoglobin. As a result, structurally abnormal hemoglobin molecules are formed. In order to detect such molecular disorder, hemoglobin samples of β-thalassemia patients are collected, lyophilized and measured using a conventional X-ray diffractometer. Results show significant differences in the X-ray scattering profiles of most of the diseased samples compared to control. The shape of the first scattering peak at 0.27 nm -1, in addition to the relative intensity of the first to the second scattering peaks, provides the most reliable signs of abnormality in diseased samples. The results are interpreted and confirmed with the aid of Fourier Transform Infrared (FTIR) spectroscopy of normal and thalassemia samples.

Surface phenomena of hydroxyapatite film on the nanopore formed Ti-29Nb-xZr alloy by anodization for bioimplants.

PubMed

Kim, Eun-Ju; Jeong, Yong-Hoon; Choe, Han-Cheol

2013-03-01

In this study, surface phenomena of hydroxyapatite (HA) film on the nanopore formed Ti-29Nb-xZr alloy by anodization for bioimplants have been investigated by electron beam physical vapor deposition (EB-PVD), field emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), potentiostat and contact angle. The microstructure of Ti-29Nb-xZr alloys exhibited equiaxed structure and alpha" phase decreased, whereas beta phase increased as Zr content increased. The increment of Zr contents in HA coated nanotubular Ti-29Nb-xZr alloys showed good corrosion potential in 0.9% NaCI solution. The wettability of HA coated nanotubular surface was higher than that of non-coated samples.

Texture analysis at neutron diffractometer STRESS-SPEC

NASA Astrophysics Data System (ADS)

Brokmeier, H.-G.; Gan, W. M.; Randau, C.; Völler, M.; Rebelo-Kornmeier, J.; Hofmann, M.

2011-06-01

In response to the development of new materials and the application of materials and components in advanced technologies, non-destructive measurement methods of textures and residual stresses have gained worldwide significance in recent years. The materials science neutron diffractometer STRESS-SPEC at FRM II (Garching, Germany) is designed to be applied equally to texture and residual stress analyses by virtue of its very flexible configuration. Due to the high penetration capabilities of neutrons and the high neutron flux of STRESS-SPEC it allows a combined analysis of global texture, local texture, strain pole figure and FWHM pole figure in a wide variety of materials including metals, alloys, composites, ceramics and geological materials. Especially, the analysis of texture gradients in bulk materials using neutron diffraction has advantages over laboratory X-rays and EBSD for many scientific cases. Moreover, neutron diffraction is favourable for coarse-grained materials, where bulk information averaged over texture inhomogeneities is needed, and also stands out due to easy sample preparation. In future, the newly developed robot system for STRESS-SPEC will allow much more flexibility than an Eulerian cradle as on standard instruments. Five recent measurements are shown to demonstrate the wide range of possible texture applications at STRESS-SPEC diffractometer.

In situ synchrotron X-ray diffraction study on epitaxial-growth dynamics of III–V semiconductors

NASA Astrophysics Data System (ADS)

Takahasi, Masamitu

2018-05-01

The application of in situ synchrotron X-ray diffraction (XRD) to the molecular-beam epitaxial (MBE) growth of III–V semiconductors is overviewed along with backgrounds of the diffraction theory and instrumentation. X-rays are sensitive not only to the surface of growing films but also to buried interfacial structures because of their large penetration depth. Moreover, a spatial coherence length up to µm order makes X-rays widely applicable to the characterization of low-dimensional structures, such as quantum dots and wires. In situ XRD studies during growth were performed using an X-ray diffractometer, which was combined with an MBE chamber. X-ray reciprocal space mapping at a speed matching a typical growth rate was achieved using intense X-rays available from a synchrotron light source and an area detector. The importance of measuring the three-dimensional distribution of XRD intensity in a reciprocal space map is demonstrated for the MBE growth of two-, one-, and zero-dimensional structures. A large amount of information about the growth process of two-dimensional InGaAs/GaAs(001) epitaxial films has been provided by three-dimensional X-ray reciprocal mappings, including the anisotropic strain relaxation, the compositional inhomogeneity, and the evolution of surface and interfacial roughness. For one-dimensional GaAs nanowires grown in a Au-catalyzed vapor-liquid–solid mode, the relationship between the diameter of the nanowires and the formation of polytypes has been suggested on the basis of in situ XRD measurements. In situ three-dimensional X-ray reciprocal space mapping is also shown to be useful for determining the lateral and vertical sizes of self-assembled InAs/GaAs(001) quantum dots as well as their internal strain distributions during growth.

A brief History of Neutron Scattering at the Oak Ridge High Flux Isotope Reactor

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

Nagler, Stephen E; Mook Jr, Herbert A

2008-01-01

Neutron scattering at the Oak Ridge National Laboratory dates back to 1945 when Ernest Wollan installed a modified x-ray diffractometer on a beam port of the original graphite reactor. Subsequently, Wollan and Clifford Shull pioneered neutron diffraction and laid the foundation for an active neutron scattering effort that continued through the 1950s, using the Oak Ridge Research reactor after 1958, and, starting in 1966, the High Flux Isotope Reactor, or HFIR.

Mesoporous Nitrogen Doped Carbon-Glass Ceramic Cathode for High Performance Lithium-Oxygen Battery

DTIC Science & Technology

2012-06-01

dry room with controlled moisture content. Composite 3 films on nickel foam were used as working cathodes along with lithium metal as anode and the...cathode formulation [6,7,8,9,10], efficient oxygen reduction catalysts [11,12], electrolyte compositions [13,14], effect of moisture [15], etc...specimens. Structure and purity of these materials were performed by powder X-ray diffraction (XRD) on a Rigaku D/MAX-2250 diffractometer fitted with CuKα

La+3 effectiveness replacement on the ferrite material (Cu0,2Zn0,45LaxFe2-xO4 ) On the structural and electrical and magnetic features

NASA Astrophysics Data System (ADS)

Hussain, Farouq I.; Alaa Najem, Rusul

2018-05-01

Nano ferrite with chemical formula (Ni 0.35 Cu 0.2 Zn 0.45 Lax Fe 2-x O 4), were chemically collected utilizing sol-gel auto – combustion procedure for the values of (X=0.0, 0.025, 0.05 and 0.075). The prepared samples were calcined at (900°C) for (2h), the formation of ferrite was assured using (XRD) and (SEM) techniques. X-ray diffractometer result shows that ferrite have spinal cubic phase with a particle size ranging from (22-29 nm),the Lattice constant and density (ρx-ray) increased with La+3content while the porosity was noticed to decrease. And have been studied dielectric properties It was also observed that the value of the dielectric constant and the dielectric loss factor decreased by increasing the frequency. The increase in alternating conductivity (σa.c) was also observed with increasing frequency.

Recovery of nickel and cobalt as MHP from limonitic ore leaching solution: Kinetics analysis and precipitate characterization

NASA Astrophysics Data System (ADS)

Safitri, Nina; Mubarok, M. Zaki; Winarko, Ronny; Tanlega, Zela

2018-05-01

In the present study, precipitation of nickel and cobalt as mixed hydroxide precipitate (MHP) from pregnant leach solution of nickel limonite ore from Soroako after iron removal stage was carried out. A series of MHP precipitation experiments was conducted by using MgO slurry as neutralizing agent and the effects of pH, temperature, duration of precipitation and the addition of MHP seed on the precipitation behavior of nickel, cobalt, as well as iron and manganese was studied. Characterization of MHP product was performed by particle size analyzer (PSA) as well as X-Ray Fluorescence (XRF), X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM) analyses. Kinetics analysis was made by using differential-integral method for the rate of homogenous reaction. Precipitation at pH 7, temperature 50°C for 30 minute, without seed addition resulted in nickel and cobalt recoveries of 82.8% and 92%, respectively with co-precipitated iron and manganese of 70% and 24.2%, respectively. The seed addition increases nickel and cobalt precipitations significantly to 99.9% and 99.1%, respectively. However, the addition of seed into led to a significant increase of manganese co-precipitation from 24.2% without seed addition to 39.5% at the addition of 1 g seed per 200 mL of PLS. Kinetics analysis revealed that Ni precipitation to form MHP follows the second-order reaction kinetics with activation energy of 94.6 kJ/mol.

Preparation of manganese doped cadmium sulfide nanoparticles in zincblende phase and their magnetic properties.

PubMed

Nakaya, Masafumi; Tanaka, Itaru; Muramatsu, Atsushi

2012-12-01

In this study, the random dope of Mn into CdS nanoparticles in zincblende phase has been carried out under the mild reaction condition. The resulting nanoparticles were characterized by energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), X-ray diffractometer (XRD), UV-Vis spectrometer, PL spectrometer, and SQUID. EDX showed that the compositions of Mn doped CdS nanoparticles were readily controlled. TEM showed the particle sizes were not significantly affected by the compositions, retaining to be ca. 3 nm with a narrow size distribution. UV-Vis and PL spectra of the resulting nanoparticles showed the intra-Mn level may be affected by the quantum size effect. SQUID measurement showed that the resulting nanoparticles showed diamagnetism, paramagnetism and superparamagnetism dependent on Mn content.

Cementation and Aqueous Alteration of a Sandstone Unit Under Acidic Conditions in Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Yen, A. S.; Blake, D. F.; Ming, D. W.; Morris, R. V.; Gellert, R.; Clark, B.; Vaniman, D. T.; Chipera, S. J.; Thompson, L. M.; Bristow, T. F.;

Properties of CoO doped in Glasses Prepared from Rice Hush Fly Ash in Thailand

NASA Astrophysics Data System (ADS)

Ruangtaweep, Y.; Kaewkhao, J.; Kirdsiri, K.; Kedkaew, C.; Limsuwan, P.

2011-10-01

In this work, properties of glass from local rice husk ash (RHA) in Thailand have been investigated. RHA was sintered in different temperature. Compositions and phases of RHA were analyzed by energy dispersive x-ray fluorescence spectrometer (EDXRF) and X-ray diffractometer (XRD). The glasses were melt from RHA in formula 20 Na2O : 1.0 Al2O3 : 13 B2O3 : 6.3 CaO : 0.2 Sb2O3 : 4.5 BaO : 55SiO2 (using RHA as a SiO2 source) The density values of all RHA glasses are comparable and larger than glass from pure SiO2 under same glass formula and preparing condition. These results are corresponding with refractive index values. The RHA glasses showing colorless with absorption edge in ultraviolet region were obtained. The dark blue color glasses were melted from RHA with different CoO concentration. From this part, not found to be the relation of density and refractive index of glass with CoO concentration in glass matrix. From absorption spectra, the absorption peak were appeared around 600 nm, and peak intensity are increased, with increase CoO, correspond to 4A2(4F) → 4T1(4P) state of Co2+ in tetrahedral symmetry.

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

Voßwinkel, Daniel; Heletta, Lukas; Hoffmann, Rolf-Dieter

The YIrGe{sub 2} type ternary germanides RERhGe{sub 2} (RE = Y, Gd-Ho) were synthesized from the elements by arc-melting and characterized by powder X-ray diffraction. The structure of DyRhGe{sub 2} was refined from single crystal X-ray diffractometer data: Immm, a = 426.49(9), b = 885.0(2), c = 1577.4(3) pm, wR2 = 0.0533, 637 F{sup 2} values, 30 variables (300 K data). The structure contains two crystallographically independent dysprosium atoms in pentagonal prismatic and hexagonal prismatic coordination. The three-dimensional [RhGe{sub 2}] polyanion is stabilized through covalent Rh–Ge (243–261 pm) and Ge–Ge (245–251 pm) bonding. The close structural relationship with the slightlymore » rhodium-poorer germanides RE{sub 5}Rh{sub 4}Ge{sub 10} (≡ RERh{sub 0.8}Ge{sub 2}) is discussed. Temperature-dependent magnetic susceptibility measurements reveal Pauli paramagnetism for YRhGe{sub 2} and Curie-Weiss paramagnetism for RERhGe{sub 2} with RE = Gd, Tb, Dy and Ho. These germanides order antiferromagnetically at T{sub N} = 7.2(5), 10.6(5), 8.1(5), and 6.4(5) K, respectively. - Graphical abstract: The germanides RERhGe{sub 2} (RE = Y, Gd-Ho) are new representatives of the YIrGe{sub 2} type.« less

Vacuum and low oxygen pressure influence on BaFe12O19 film deposited by pulse laser deposition

NASA Astrophysics Data System (ADS)

Kumar, Pawan; Gaur, Anurag; Choudhary, R. J.

2018-05-01

BaFe12O19 hexaferrite thin films are deposited on Si (111) substrate by the pulse laser deposition (PLD) technique in high vacuum 10-6 Torr and low oxygen pressure (10 mTorr) at 650°C substrate temperature. The effects of high vacuum and low pressure on magnetic and optical properties are studied. These films are characterized by the x-ray diffractometer (XRD), SQUID-VSM magnetometer, and Photo-luminescence spectroscopy. XRD pattern reveals that the BaFe12O19 film well formed in both environments without any impurity pick. High magnetic saturazation 317 emu/cm3 and coercivity 130 Oe are observed for the film deposited in vacuum. Photoluminescence emission spectrum of BaFe12O19 film reveals that the higher intensity emission peak at ˜372 nm under the excitation wavelength of 270 nm is observed for the film grown in vacuum.

Microstructure and optical properties of nanocrystalline Cu2O thin films prepared by electrodeposition.

PubMed

Jiang, Xishun; Zhang, Miao; Shi, Shiwei; He, Gang; Song, Xueping; Sun, Zhaoqi

2014-01-01

Cuprous oxide (Cu2O) thin films were prepared by using electrodeposition technique at different applied potentials (-0.1, -0.3, -0.5, -0.7, and -0.9 V) and were annealed in vacuum at a temperature of 100°C for 1 h. Microstructure and optical properties of these films have been investigated by X-ray diffractometer (XRD), field-emission scanning electron microscope (SEM), UV-visible (vis) spectrophotometer, and fluorescence spectrophotometer. The morphology of these films varies obviously at different applied potentials. Analyses from these characterizations have confirmed that these films are composed of regular, well-faceted, polyhedral crystallites. UV-vis absorption spectra measurements have shown apparent shift in optical band gap from 1.69 to 2.03 eV as the applied potential becomes more cathodic. The emission of FL spectra at 603 nm may be assigned as the near band-edge emission.

Investigation of site preference of Zn doped Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} by Mössbauer spectroscopy

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

Lim, Jung Tae; Kim, Chul Sung, E-mail: cskim@kookmin.ac.kr

2014-05-07

The polycrystalline Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0) samples were prepared by using solid-state-reaction method. The crystal structures and magnetic properties of samples were investigated with x-ray diffractometer, vibrating sample magnetometer, and Mössbauer spectroscopy. The crystal structure of Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0) samples was determined to be a hexagonal structure with P6{sub 3}/mmc space group at 295 K, and the saturation magnetization (M{sub s}) of Ba{sub 3}Co{sub 2−x}Zn{sub x}Fe{sub 24}O{sub 41} (x = 0.0, 0.5, 1.0) samples were found to be M{sub s} = 50.9, 53.1, 55.0 emu/g, respectively. From the temperature dependence of magnetizationmore » curves under 100 Oe between 4.2 and 740 K, we were able to observe the spin transition, and both spin transition temperature (T{sub s}) and Curie temperature (T{sub C}) decrease with increasing Zn concentration. Mössbauer spectra of all samples were obtained and analyzed at various temperatures ranging from 4.2 to 295 K. With ten-sextets for Fe sites corresponding to the Z-type hexagonal crystallographic sites, all spectra below T{sub C} were fitted by least-square method. In addition, from the site occupation numbers of Fe, calculated from the relative areas fitted to the Mössbauer spectra, we find that Zn ions preferentially occupy the tetrahedral sublattices of down sites.« less

X-Ray diffraction on large single crystals using a powder diffractometer

DOE PAGES

Jesche, A.; Fix, M.; Kreyssig, A.; ...

2016-06-16

Information on the lattice parameter of single crystals with known crystallographic structure allows for estimations of sample quality and composition. In many cases it is sufficient to determine one lattice parameter or the lattice spacing along a certain, high- symmetry direction, e.g. in order to determine the composition in a substitution series by taking advantage of Vegard’s rule. Here we present a guide to accurate measurements of single crystals with dimensions ranging from 200 μm up to several millimeter using a standard powder diffractometer in Bragg-Brentano geometry. The correction of the error introduced by the sample height and the optimizationmore » of the alignment are discussed in detail. Finally, in particular for single crystals with a plate-like habit, the described procedure allows for measurement of the lattice spacings normal to the plates with high accuracy on a timescale of minutes.« less

Experimental and theoretical investigation of the rocking curves measured for MoK{sub α} X-ray characteristic lines in the double-crystal nondispersive scheme

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

Marchenkov, N. V., E-mail: marchenkov@ns.crys.ras.ru; Chukhovskii, F. N.; Blagov, A. E.

2015-03-15

The rocking curves (RCs) for MoK{sub α1} and MoK{sub α2} characteristic X-ray lines have been experimentally and theoretically studied in the nondispersive scheme of an X-ray double-crystal TPC-K diffractometer. The results of measurements and theoretical calculations of double-crystal RCs for characteristic X-rays from tubes with a molybdenum anode and different widths of slits show that a decrease in the slit width leads to an increase in the relative contribution of the MoK{sub α2}-line RC in comparison with the intensity of the tails of the MoK{sub α1}-line RC. It is shown that the second peak of the MoK{sub α2} line becomesmore » increasingly pronounced in the tail of the MoK{sub α1}-line RC with a decrease in the slit width. Two plane-parallel Si plates (input faces (110), diffraction vector h 〈220〉) were used as a monochromator crystal and a sample. The results of measuring double-crystal RCs are in good agreement with theoretical calculations.« less

Micromorphology of sialoliths in submandibular salivary gland: a scanning electron microscope and X-ray diffraction analysis.

PubMed

Kasaboğlu, Oğuzcan; Er, Nuray; Tümer, Celal; Akkocaoğlu, Murat

2004-10-01

Sialoliths are common in the submandibular gland and its duct system. The exact cause of formation of a sialolith is still a matter of debate. The aim of this study was to analyze 6 sialoliths ultrastructurally to determine their development mechanism in the submandibular salivary glands. Six sialoliths retrieved from the hilus and duct of the submandibular salivary glands of 6 patients with sialadenitis were analyzed ultrastructurally by scanning electron microscope and x-ray diffractometer. Scanning electron microscope revealed mainly irregular, partly rudely hexagonal, needle-like and plate-shaped crystals. The cross-section from the surface to the inner part of the sialoliths showed no organic material. X-ray diffraction showed that the sialoliths were composed of hydroxyapatite crystals. Energy dispersive x-ray microanalysis showed that all of the samples contained high levels of Ca and P, and small amounts of Mg, Na, Cl, Si, Fe, and K. The main structures of the submandibular sialoliths were found to be hydroxyapatite crystals. No organic cores were observed in the central parts of the sialoliths. In accordance with these preliminary results, sialoliths in the submandibular salivary glands may arise secondary to sialadenitis, but not via a luminal organic nidus.

GeoSoilEnviroCARS: A National User Facility for Synchrotron Radiation Research

NASA Astrophysics Data System (ADS)

Rivers, M. L.; Sutton, S. R.

2002-12-01

GeoSoilEnviroCARS (GSECARS) is a national user facility for frontier research in the earth sciences using synchrotron radiation at the Advanced Photon Source, Argonne National Laboratory. GSECARS provides earth scientists with access to the high-brilliance hard x-rays from this third-generation synchrotron light source. Both an undulator and a bending magnet beamline are available. All principal synchrotron-based analytical techniques in demand by earth scientists are being brought to bear on earth science problems: (1) high-pressure/high-temperature crystallography and spectroscopy using the diamond anvil cell; (2) high-pressure/high-temperature crystallography using the large-volume press; (3) powder, single crystal and interface diffraction; (4) inelastic x-ray scattering; (5) x-ray absorption fine structure (XAFS) spectroscopy; (6) x-ray fluorescence microprobe analysis; and (7) microtomography. The major instrumentation includes 250 and 1000 MN multianvil presses, a double-sided laser heating system, a large general-purpose 5-circle diffractometer, a focused microprobe, and a Raman laboratory. A proposal-based system for beamtime allocation, open to all earth scientists, has been in place since Fall, 1998. Since then, over 450 beamtime proposals have been received and more than 320 outside users have conducted experiments at GSECARS. The research conducted by these investigators has resulted in more than 170 publications. The unique capabilities of the APS and GSECARS have allowed groundbreaking experiments to be conducted. These include: (1) phase transformations in the Mg-Si-O system at mantle conditions; (2) structure of hydrated a-Al2O3 surfaces; (3) alloying properties of silicon in the Earth's core; (4) dynamics of iron-rich melt segregation from silicates during core formation; (5) electronic spin state of FeO at high pressure and temperature; (6) elastic wave velocities of mantle minerals at lower mantle conditions; (7) copper partitioning and speciation in natural hydrothermal fluids; and (8) mechanisms of arsenic sequestration at a Superfund site. The GSECARS mission is to provide a research environment where users receive expert assistance in planning and conducting experiments, and in analyzing data. The facility operation is funded by the NSF EAR Instrumentation and Facilities program and the DOE Geosciences program. Major instrumentation was also provided by the W.M. Keck Foundation. Information and applications for beam time can be found at http://gsecars.org.

Role of annealing temperature on microstructural and electro-optical properties of ITO films produced by sputtering

NASA Astrophysics Data System (ADS)

Senol, Abdulkadir; Gulen, Mahir; Yildirim, Gurcan; Ozturk, Ozgur; Varilci, Ahmet; Terzioglu, Cabir; Belenli, Ibrahim

2013-03-01

In this study, we investigate the effect of annealing temperature on electrical, optical and microstructural properties of indium tin oxide (ITO) films deposited onto Soda lime glass substrates by conventional direct current (DC) magnetron reactive sputtering technique at 100 watt using an ITO ceramic target (In2O3:SnO2, 90:10 wt. %) in argon atmosphere at room temperature. The films obtained are exposed to the calcination process at different temperature up to 700 ° C. Resistivity, Hall Effect, X-ray diffractometer (XRD), ultra violet-visible spectrometer (UV-vis) and atomic force microscopy (AFM) measurements are performed to characterize the samples. Moreover, phase purity, surface morphology, optical and photocatalytic properties of the films are compared with each other. Furthermore, mobility, carrier density and conductivity characteristics of the samples prepared are carried out as function of temperature in the range of 80-300 K at the magnetic field of 0.550 T. The results obtained show that all the properties depend strongly on the annealing temperature and in fact the film annealed at 400 ° C obtains the better optical properties due to the high refractive index while the film produced at 100 °C exhibits much better photoactivity than the other films as a result of the large optical energy band gap.

Phase, compositional, and morphological changes of human dentin after Nd:YAG laser treatment.

PubMed

Lin, C P; Lee, B S; Lin, F H; Kok, S H; Lan, W H

2001-06-01

Although techniques for repairing root fracture have been proposed, the prognosis is generally poor. If the fusion of a root fracture by laser is possible, it will offer an alternative to extraction. Our group has attempted to use lasers to fuse a low melting-point bioactive glass to fractured dentin. This report is focused on the phase, compositional, and morphological changes observed by means of X-ray diffractometer, Fourier transforming infrared spectroscopy, and scanning electron microscopy-energy dispersive X-ray spectroscopy in human dentin after exposure to Nd:YAG laser. The irradiation energies were from 150 mJ/ pulse-10 pps-4 s to 150 mJ/pulse-30 pps-4 s. After exposure to Nd:YAG laser, dentin showed four peaks on the X-ray diffractometer that corresponding to a-tricalcium phosphate (TCP) and beta-TCP at 20 = 30.78 degrees/34.21 degrees and 32.47 degrees/33.05 degrees, respectively. The peaks of a-TCP and beta-TCP gradually increased in intensity with the elevation of irradiation energy. In Fourier transforming infrared analysis, two absorption bands at 2200 cm(-1) and 2015 cm(-1) could be traced on dentin treated by Nd:YAG laser with the irradiation energies beyond 150 mJ/pulse-10 pps-4 s. The energy dispersive X-ray results showed that the calcium/phosphorus ratios of the irradiated area proportionally increased with the elevation of irradiation energy. The laser energies of 150 mJ/ pulse-30 pps-4 s and 150 mJ/pulse-20 pps-4 s could result in the a-TCP formation and collagen breakdown. However, the formation of glass-like melted substances without a-TCP at the irradiated site was induced by the energy output of 150 mJ/ pulse-10 pps-4 s. Scanning electron micrographs also revealed that the laser energy of 150 mJ/ pulse-10 pps-4 s was sufficient to prompt melting and recrystallization of dentin crystals without cracking. Therefore, we suggest that the irradiation energy of Nd:YAG laser used to fuse a low melting-point bioactive glass to dentin is 150 mJ/ pulse-10 pps-4 s.

Destination Innovation: Episode 4 CheMin

NASA Image and Video Library

2012-08-02

Destination Innovation is a new series that explores the research, science and other projects underway at the NASA Ames Research Center. Episode 4 focuses on the CheMin instrument aboard the Mars Science Laboratory, NASA' s latest robotic explorer to visit Mars. CheMin, short for 'Chemistry and Mineralogy,' was developed at NASA Ames Research Center and is one of 10 instruments aboard the rover Curiosity. The instrument is an x-ray diffractometer, which will be able to identify minerals in the Martial rock and soil.

Effect of Sc{sup 3+} on structural and magnetic properties of Mn-Zn nano ferrites

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

Angadi, Jagadeesha V.; Matteppanavar, Shidaling; Srinatha, N.

2016-05-23

In the present investigation, for the first time, we report on the effect of Sc{sup 3+} on the structural and magnetic properties of Mn{sub 0.5}Zn{sub 0.5}Sc{sub y}Fe{sub 2-y}O{sub 4} (y = 0.01, 0.03 and 0.05) nanoferrites synthesized by solution combustion method using the mixture of fuels. As synthesized powders were characterized for the detailed structural analysis by X-ray diffractometer (XRD), Fourier transmission infrared spectroscopy (FTIR) and room temperature magnetic properties by using vibrating sample magnetometer (VSM). The results of XRD and FTIR confirm that the formation of nano crystalline, single-phased Mn-Zn ferrite with cubic spinel structure belongs to Fd-3m spacemore » group. The room temperature magnetic studies shows that, the saturation magnetization (M{sub S}), remanence magnetization (M{sub R}) and magnetic moment (η{sub B}), magnetic particle size (D{sub m}) have found to increase with Sc{sup 3+} ion concentration up to x = 0.3 and then decrease. The values of αY-K and the magnetic particle size (D{sub m}) are found to be in the range of 68-75° and 10-19 nm respectively, with Sc{sup 3+} concentration.« less

[Preparation and characterization of magnetic nano-particles with radiofrequency-induced hyperthermia for cancer treatment].

PubMed

Fan, Xiangshan; Zhang, Dongsheng; Zheng, Jie; Gu, Ning; Ding, Anwei; Jia, Xiupeng; Qing, Hongyun; Jin, Liqiang; Wan, Meiling; Li, Qunhui

2006-08-01

Mn0.5Zn0.5Fe2O4 nano-particles were prepared by the chemical co-precipitation, their characteristics were observed with transmission electron microscope (TEM), X-ray diffractometer (XRD) and thermal analysis system, and etc. The temperature changes of the nano-particles of Mn0.5Zn0.5Fe2O4 and its magnetic fluid explored in radiofrequency(RF,200 KHz, 4 KW) were measured. The proliferation ratio of L929 cells cultured in soak of Mn0.5Zn0.5Fe2O4 nano-particles were observed. The experiment indicates that the magnetic particles were about 40 nm diameter in average, round, had strong magnetism, and were proved to be consistent with the standard data of chart of XRD. Its magnetic fluid exposed to RF could be heated up to temperature range from 40 degrees C to 51 degrees C due to the amount of the magnetic nano-particles and intensity of the alternating magnetic field. Magnetic nano-particles were found to have no obvious cytotoxicity to L929 cells.

[Characteristics and mechanism of sodium removal by the synergistic action of flue gas and waste solid].

PubMed

Yi, Yuan-Rong; Han, Min-Fang

2012-07-01

The carbon dioxide (CO2) in flue gas was used to remove the sodium in the red mud (RM) , a kind of alkaline solid waste generated during alumina production. The reaction characteristics and mechanism of sodium removal by the synergistic action of CO2 and RM were studied with different medium pH, reaction time and temperature. It was demonstrated that the remove of sodium by RM was actually the result of the synergistic action of sodium-based solid waste in RM with the CO2-H2O and OH(-)-CO2 systems. The sodium removal efficiency was correlated with pH, reaction temperature and time. The characteristics of RM before and after sodium removal were analyzed using X-ray diffractometer (XRD) and scanning electron microscope (SEM), and the results showed that the alkaline materials in the red mud reacted with CO2 and the sodium content in solid phases decreased significantly after reaction. The sodium removal efficiency could reach up to 70% with scientific procedure. The results of this research will offer an efficient way for low-cost sodium removal.

Electrical characteristics of organic perylene single-crystal-based field-effect transistors

NASA Astrophysics Data System (ADS)

Lee, Jin-Woo; Kang, Han-Saem; Kim, Min-Ki; Kim, Kihyun; Cho, Mi-Yeon; Kwon, Young-Wan; Joo, Jinsoo; Kim, Jae-Il; Hong, Chang-Seop

2007-12-01

We report on the fabrication of organic field-effect transistors (OFETs) using perylene single crystal as the active material and their electrical characteristics. Perylene single crystals were directly grown from perylene powder in a furnace using a relatively short growth time of 1-3 h. The crystalline structure of the perylene single crystals was characterized by means of a single-crystal x-ray diffractometer. In order to place the perylene single crystal onto the Au electrodes of the field-effect transistor, a polymethlymethacrylate thin layer was spin-coated on top of the crystal surface. The OFETs fabricated using the perylene single crystal showed a typical p-type operating mode. The field-effect mobility of the perylene crystal based OFETs was measured to be ˜9.62×10-4 cm2/V s at room temperature. The anisotropy of the mobility implying the existence of different mobilities when applying currents in different directions was observed for the OFETs, and the existence of traps in the perylene crystal was found through the measurements of the temperature-dependent mobility at various operating drain voltages.

From Modeling of Plasticity in Single-Crystal Superalloys to High-Resolution X-rays Three-Crystal Diffractometer Peaks Simulation

NASA Astrophysics Data System (ADS)

Jacques, Alain

2016-12-01

The dislocation-based modeling of the high-temperature creep of two-phased single-crystal superalloys requires input data beyond strain vs time curves. This may be obtained by use of in situ experiments combining high-temperature creep tests with high-resolution synchrotron three-crystal diffractometry. Such tests give access to changes in phase volume fractions and to the average components of the stress tensor in each phase as well as the plastic strain of each phase. Further progress may be obtained by a new method making intensive use of the Fast Fourier Transform, and first modeling the behavior of a representative volume of material (stress fields, plastic strain, dislocation densities…), then simulating directly the corresponding diffraction peaks, taking into account the displacement field within the material, chemical variations, and beam coherence. Initial tests indicate that the simulated peak shapes are close to the experimental ones and are quite sensitive to the details of the microstructure and to dislocation densities at interfaces and within the soft γ phase.

The system K2Mg2(SO4)3 (langbeinite)-K2Ca2(SO4)3 (calcium-langbeinite)

USGS Publications Warehouse

Morey, G.W.; Rowe, J.J.; Fournier, R.O.

1964-01-01

The join between the compositions K2Mg2(SO4)3 and K2Ca2(SO4)3 was studied by means of high-temperature equilibrium quenching techniques and by means of a heating stage mounted on an X-ray diffractometer. Complete solid solution exists in the system, but at 25??C members of the solid solution series are isometric only in the composition range 0-73??5 wt. per cent K2Ca2(SO4)3. At compositions richer in K2Ca2(SO4)3 than 73??5 wt. per cent, members of the series are optically biaxial. At higher temperatures members of the solid solution series are isometric at successively more calcium-rich compositions and pure K2Ca2(SO4)3 is isometric above about 200 ?? 2??C. The system is not binary, as mixtures richer in K2Ca2(SO4)3 than 42 wt. per cent decompose with the formation of liquid and CaSO4. ?? 1964.

The crystal structure of the new ternary antimonide Dy 3Cu 20+xSb 11-x ( x≈2)

NASA Astrophysics Data System (ADS)

Fedyna, L. O.; Bodak, O. I.; Fedorchuk, A. O.; Tokaychuk, Ya. O.

2005-06-01

New ternary antimonide Dy 3Cu 20+xSb 11-x ( x≈2) was synthesized and its crystal structure was determined by direct methods from X-ray powder diffraction data (diffractometer DRON-3M, Cu Kα-radiation, R=6.99%,R=12.27%,R=11.55%). The compound crystallizes with the own cubic structure type: space group F 4¯ 3m, Pearson code cF272, a=16.6150(2) Å,Z=8. The structure of the Dy 3Cu 20Sb 11-x ( x≈2) can be obtained from the structure type BaHg 11 by doubling of the lattice parameter and subtraction of 16 atoms. The studied structure was compared with the structures of known compounds, which crystallize in the same space group with similar cell parameters.

Structural, electrical and mechanical properties of selenium doped thallium based high-temperature superconductors

NASA Astrophysics Data System (ADS)

Cavdar, S.; Kol, N.; Koralay, H.; Ozturk, O.; Asikuzun, E.; Tasci, A. T.

2016-01-01

In this study, highly-refined chemical powders were synthesized by having them ready in appropriate stoichiometric proportions with conventional solid state reaction method so that they would produce the superconductor TlPb0.3Sr2Ca1-xSexCu2Oy (x = 0; 0.4; 0.6; 1.0). This study aims to understand effect of the selenium doping on the superconducting, structural and mechanical properties of the aforementioned superconducting material. The effect of the doping rates on the structural and electrical properties of the sample has been identified. Electrical characteristics of the TlPb0.3Sr2Ca1-xSexCu2Oy material were measured using standard four point probe method. Structural characteristics were examined with the powder X-ray diffractometer (XRD) and scanning electron microscope (SEM). Mechanical properties were analyzed with Vickers microhardness measurements on the sample surface. According to the results, it was observed that the reflection comes from the (00l) and parallel planes increased with Se doping. Particle size increases with increasing doping ratio. According to results of the mechanical measurements, all samples exhibit indentation size effect (ISE) behavior. Comparing the obtained results with theoretical studies, it was understood that Hays Kendall approach is the best method in determination of mechanical properties and analyzing microhardness of the materials.

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

Madden, Jeremy T.; Toth, Scott J.; Dettmar, Christopher M.

Nonlinear optical (NLO) instrumentation has been integrated with synchrotron X-ray diffraction (XRD) for combined single-platform analysis, initially targeting applications for automated crystal centering. Second-harmonic-generation microscopy and two-photon-excited ultraviolet fluorescence microscopy were evaluated for crystal detection and assessed by X-ray raster scanning. Two optical designs were constructed and characterized; one positioned downstream of the sample and one integrated into the upstream optical path of the diffractometer. Both instruments enabled protein crystal identification with integration times between 80 and 150 µs per pixel, representing a ~10 3–10 4-fold reduction in the per-pixel exposure time relative to X-ray raster scanning. Quantitative centering andmore » analysis of phenylalanine hydroxylase fromChromobacterium violaceumcPAH,Trichinella spiralisdeubiquitinating enzyme TsUCH37, human κ-opioid receptor complex kOR-T4L produced in lipidic cubic phase (LCP), intimin prepared in LCP, and α-cellulose samples were performed by collecting multiple NLO images. The crystalline samples were characterized by single-crystal diffraction patterns, while α-cellulose was characterized by fiber diffraction. Good agreement was observed between the sample positions identified by NLO and XRD raster measurements for all samples studied.« less

Unconventional Synthesis of γ-Fe2O3: Excellent Low-Concentration Ethanol Sensing Performance

NASA Astrophysics Data System (ADS)

Naskar, Atanu; Narjinary, Mousumi; Kundu, Susmita

2017-01-01

This study reports on a simple unconventional procedure for synthesis of γ-Fe2O3 nanopowder and its fabrication as a resistive ethanol sensor. γ-Fe2O3 powder having an average particle size of ˜15 nm was prepared by thermal decomposition of iron(III) acetylacetonate. Platinum incorporation (0.5-1.5 wt.%) was also carried out for enhancing sensing performance. The powders were characterized using an x-ray diffractometer, x-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area, field area scanning electron microscopy, transmission electron microscopy along with energy dispersion x-ray analyses. Sensor fabricated from pure γ-Fe2O3 exhibited excellent ethanol sensing performance at concentrations down to 1 ppm, having a great demand in medical diagnosis and food-processing industries. The response observed for pure γ-Fe2O3 (˜75% for 1 ppm ethanol) was enhanced ˜10% after 1 wt.% Pt impregnation. Sensors were quite stable and selective towards ethanol vapour detection. A possible mechanism for high sensing performance has been discussed.

Crystal growth, structural, thermal and mechanical behavior of l-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) single crystals.

PubMed

Mahadevan, M; Ramachandran, K; Anandan, P; Arivanandhan, M; Bhagavannarayana, G; Hayakawa, Y

2014-12-10

Single crystals of l-arginine 4-nitrophenolate 4-nitrophenol dihydrate (LAPP) have been grown successfully from the solution of l-arginine and 4-nitrophenol. Slow evaporation of solvent technique was adopted to grow the bulk single crystals. Single crystal X-ray diffraction analysis confirms the grown crystal has monoclinic crystal system with space group of P21. Powder X-ray diffraction analysis shows the good crystalline nature. The crystalline perfection of the grown single crystals was analyzed by HRXRD by employing a multicrystal X-ray diffractometer. The functional groups were identified from proton NMR spectroscopic analysis. Linear and nonlinear optical properties were determined by UV-Vis spectrophotometer and Kurtz powder technique respectively. It is found that the grown crystal has no absorption in the green wavelength region and the SHG efficiency was found to be 2.66 times that of the standard KDP. The Thermal stability of the crystal was found by obtaining TG/DTA curve. The mechanical behavior of the grown crystal has been studied by Vicker's microhardness method. Copyright © 2014 Elsevier B.V. All rights reserved.

Tandem transmission/reflection mode XRD instrument including XRF for in situ measurement of Martian rocks and soils

NASA Astrophysics Data System (ADS)

Delhez, Robert; Van der Gaast, S. J.; Wielders, Arno; de Boer, J. L.; Helmholdt, R. B.; van Mechelen, J.; Reiss, C.; Woning, L.; Schenk, H.

2003-02-01

The mineralogy of the surface material of Mars is the key to disclose its present and past life and climates. Clay mineral species, carbonates, and ice (water and CO2) are and/or contain their witnesses. X-ray powder diffraction (XRPD) is the most powerful analytical method to identify and quantitatively characterize minerals in complex mixtures. This paper discusses the development of a working model of an instrument consisting of a reflection mode diffractometer and a transmission mode CCD-XRPD instrument, combined with an XRF module. The CCD-XRD/XRF instrument is analogous to the instrument for Mars missions developed by Sarrazin et al. (1998). This part of the tandem instrument enables "quick and dirty" analysis of powdered (!) matter to monitor semi-quantitatively the presence of clay minerals as a group, carbonates, and ices and yields semi-quantitative chemical information from X-ray fluorescence (XRF). The reflection mode instrument (i) enables in-situ measurements of rocks and soils and quantitative information on the compounds identified, (ii) has a high resolution and reveals large spacings for accurate identification, in particular of clay mineral species, and (iii) the shape of the line profiles observed reveals the kind and approximate amounts of lattice imperfections present. It will be shown that the information obtained with the reflection mode diffractometer is crucial for finding signs of life and changes in the climate on Mars. Obviously this instrument can also be used for other extra-terrestrial research.

In situ X-ray diffraction strain-controlled study of Ti–Nb–Zr and Ti–Nb–Ta shape memory alloys: crystal lattice and transformation features

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

Dubinskiy, S.; National University of Science and Technology “MISIS”, 4, Leninskiy prosp., Moscow 119049; Prokoshkin, S.

2014-02-15

Phase and structure transformations in biomedical Ti–21.8Nb–6.0Zr (TNZ) and Ti–19.7Nb–5.8Ta (TNT) shape memory alloys (at.%) under and without load in the − 150 to 100 °S temperature range are studied in situ using an original tensile module for a low-temperature chamber of an X-ray diffractometer. Alpha″- and beta-phase lattice parameters, the crystallographic resource of recovery strain, phase and structure transformation sequences, and microstress appearance and disappearance are examined, compared and discussed. For both alloys, the crystallographic resource of recovery strain decreases with temperature increase to become 4.5% for TNZ and 2.5% for TNT alloy (at RT). Loading at low temperaturesmore » leads to additional α″-phase formation and reorientation. Heating under load, as compared to strain-free heating, affects the reverse transformation sequence of both alloys in different ways. For TNZ alloy, strain-free heating results in simultaneous ω→β and α″→β transformations, whereas during heating under stress, they are sequential: β + ω→α″ precedes α″→β. For TNT alloy, strain-free heating results in reverse α″→β transformation, whereas during heating under stress, α″→β transformation is preceded by α″-phase reorientation. - Highlights: • Comparative in situ XRD analysis of Ti–Nb–Zr(Ta) shape memory alloys is realized. • Lattice parameters of β- and α″-phases are calculated in the − 150 to + 100 °C range. • The higher the temperature, the lower the α″→β transformation strain. • Loading at low temperatures results in α″-phase formation and reorientation. • Transformation sequences upon heating with and without loading are different.« less

Performance of RF sputtered p-Si/n-ZnO nanoparticle thin film heterojunction diodes in high temperature environment

NASA Astrophysics Data System (ADS)

Singh, Satyendra Kumar; Hazra, Purnima

2017-04-01

In this article, temperature-dependent current-voltage characteristics of n-ZnO/p-Si nanoparticle thin film heterojunction diode grown by RF sputtering technique are analyzed in the temperature range of 300-433 k to investigate the performance of the device in high temperature environment. The microstructural, morphological, optical and temptrature dependent electrical properties of as-grown nanoparticle thin film were characterized by X-ray diffractometer (XRD), atomic force microscopy (AFM), field emmision scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), variable angle ellipsometer and semiconductor device analyzer. XRD spectra of as-grown ZnO films are exhibited that highly c-axis oriented ZnO nanostructures are grown on p- Si〈100〉 substrate whereas AFM and FESEM images confirm the homogeneous deposition of ZnO nanoparticles on surface of Si substratewith minimum roughness.The optical propertiesof as-grown ZnO nanoparticles have been measured in the spectral range of 300-800 nm using variable angle ellipsometer.To measure electrical parameters of the device prototype in the temperature range of room temperature (300 K) to 433 K, large area ohmic contacts were fabricated on both side of the ZnO/Si heterostructure. From the current-voltage charcteristics of ZnO/Si heterojunction device, it is observed that the device exhibits rectifing nature at room temperature. However, with increase in temperature, reverse saturation current and barrier height are found to increase, whereas ideality factor is started decreasing. This phenomenon confirms that barrier inhomogeneities are present at the interface of ZnO/Si heterojunction, as a result of lattice constant and thermal coefficient mismatch between Si and ZnO. Therefore, a modified value of Richardson constant [33.06 Acm-2K-2] has been extracted from the temperature-dependent electrical characteristics after assuming the Gaussian distribution of special barrier height inhomogeneities across the Si/ZnO interface which is close to its theoretical value [32 Acm-2K-2]. This result indicates that regardless of presence of barrier height inmogeneities, ZnO/Si heterojunction diode still hasability to perform well in high temperature environment.

Composition and crystal structure of N doped TiO2 film deposited at different O2 flow rate by direct current sputtering.

PubMed

Ding, Wanyu; Ju, Dongying; Chai, Weiping

2011-06-01

N doped Ti02 films were deposited by direct current pulse magnetron sputtering system at room temperature. The influence of 02 flow rate on the crystal structure of deposited films was studied by Stylus profilometer, X-ray photoelectron spectroscopy, and X-ray diffractometer. The results indicate that the 02 flow rate strongly controls the growth behavior and crystal structure of N doped Ti02 film. It is found that N element mainly exists as substitutional doped state and the chemical stiochiometry is near to TiO1.68±0.06N0.11±0.01 for all film samples. N doped Ti02 film deposited with 2 sccm (standard-state cubic centimeter per minute) 02 flow rate is amorphous structure with high growth rate, which contains both anatase phase and rutile phase crystal nucleuses. In this case, the film displays the mix-phase of anatase and rutile after annealing treatment. While N doped Ti02 film deposited with 12 cm(3)/min 02 flow rate displays anatase phase before and after annealing treatment. And it should be noticed that no TiN phase appears for all samples before and after annealing treatment. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Dissolution and precipitation behaviors of silicon-containing ceramic coating on Mg-Zn-Ca alloy in simulated body fluid.

PubMed

Pan, Yaokun; Chen, Chuanzhong; Wang, Diangang; Huang, Danlan

2014-10-01

We prepared Si-containing and Si-free coatings on Mg-1.74Zn-0.55Ca alloy by micro-arc oxidation. The dissolution and precipitation behaviors of Si-containing coating in simulated body fluid (SBF) were discussed. Corrosion products were characterized by scanning electron microscope (SEM), X-ray diffractometer (XRD), fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectrometer (XPS). Electrochemical workstation, inductively coupled plasma atomic emission spectrometer (ICP-AES), flame atomic absorption spectrophotometer (AAS) and pH meter were employed to detect variations of electrochemical parameter and ions concentration respectively. Results indicate that the fast formation of calcium phosphates is closely related to the SiOx(n-) groups, which induce the heterogeneous nucleation of amorphous hydroxyapatite (HA) by sorption of calcium and phosphate ions. Copyright © 2014 Elsevier B.V. All rights reserved.

Geotechnical characterization of some Indian fly ashes

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

Das, S.K.; Yudhbir

2005-10-01

This paper reports the findings of experimental studies with regard to some common engineering properties (e.g., grain size, specific gravity, compaction characteristics, and unconfined compression strength) of both low and high calcium fly ashes, to evaluate their suitability as embankment materials and reclamation fills. In addition, morphology, chemistry, and mineralogy of fly ashes are studied using scanning electron microscope, electron dispersive x-ray analyzer, x-ray diffractometer, and infrared absorption spectroscopy. In high calcium fly ash, mineralogical and chemical differences are observed for particles, {gt}75 {mu} m and the particles of {lt} 45 {mu} m size. The mode and duration of curingmore » significantly affect the strength and stress-strain behavior of fly ashes. The geotechnical properties of fly ash are governed by factors like lime content (CaO), iron content (Fe{sub 2}O{sub 3}) and loss on ignition. The distinct difference between self-hardening and pozzolanic reactivity has been emphasized.« less

Low orthopyroxene from a lunar deep crustal rock - A new pyroxene polymorph of space group P21ca

NASA Technical Reports Server (NTRS)

Smyth, J. R.

1974-01-01

Bronzite crystals (En86Fs11Wo3) from a slowly-cooled lunar troctolitic granulite, have space group P21ca, a postulated, but previously unreported space group. Diffractions violating the b-glide extinction conditions have been observed in long-exposure X-ray precession photographs from three of these crystals and on an automated X-ray diffractometer. P21ca is a subgroup of the common orthopyroxene space group Pbca, and its cell dimensions (a = 18.235 plus or minus 0.004 A, b = 8.831 plus or minus 0.002 A, c = 5.189 plus or minus 0.001 A) are similar to those of terrestrial bronzites. It is postulated that the lower symmetry space group has developed as a result of very slow cooling at pressures of one to two kilobars deep in the lunar crust.

Simultaneous recovery of phosphorus and potassium as magnesium potassium phosphate from synthetic sewage sludge effluent.

PubMed

Nakao, Satoshi; Nishio, Takayuki; Kanjo, Yoshinori

2017-10-01

Bench-scale experiments were performed to investigate simultaneous recovery of phosphorus and potassium from synthetic sewage sludge effluent as crystals of magnesium potassium phosphate (MPP or struvite-(K), MgKPO 4 ·6H 2 O). The optimal pH of MPP formation was 11.5. A phosphorus level of at least 3 mM and K:P molar ratio over 3 were necessary to form MPP, which showed higher content rate of phosphorus and potassium in precipitate. MPP crystallization was confirmed by analysing the precipitates using a scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) apparatus and an X-ray Diffractometer (XRD). Inhibition of MPP crystallization by iron and aluminium was confirmed by precipitation experiments and SEM-EDX analysis. Potassium ratio against magnesium in precipitate decreased for iron concentrations greater than over 0.2 mM and aluminium concentrations over 0.05 mM.

The new HMI beamline MAGS: an instrument for hard X-ray diffraction at BESSY.

PubMed

Dudzik, Esther; Feyerherm, Ralf; Diete, Wolfgang; Signorato, Riccardo; Zilkens, Christopher

2006-11-01

The Hahn-Meitner-Institute Berlin is operating the new hard X-ray diffraction beamline MAGS at the Berlin synchrotron radiation source BESSY. The beamline is intended to complement the existing neutron instrumentation at the Berlin Neutron Scattering Centre. The new beamline uses a 7 T multipole wiggler to produce photon fluxes in the 10(11)-10(12) photons s(-1) (100 mA)(-1) (0.1% bandwidth)(-1) range at energies from 4 to 30 keV at the experiment. It has active bendable optics to provide flexible horizontal and vertical focusing and to compensate the large heat load from the wiggler source. The experimental end-station consists of a six-circle Huber diffractometer which can be used with an additional (polarization) analyser and different sample environments. The beamline is intended for single-crystal diffraction and resonant magnetic scattering experiments for the study of ordering phenomena, phase transitions and materials science.

Hydrogen atoms can be located accurately and precisely by x-ray crystallography.

PubMed

Woińska, Magdalena; Grabowsky, Simon; Dominiak, Paulina M; Woźniak, Krzysztof; Jayatilaka, Dylan

2016-05-01

Precise and accurate structural information on hydrogen atoms is crucial to the study of energies of interactions important for crystal engineering, materials science, medicine, and pharmacy, and to the estimation of physical and chemical properties in solids. However, hydrogen atoms only scatter x-radiation weakly, so x-rays have not been used routinely to locate them accurately. Textbooks and teaching classes still emphasize that hydrogen atoms cannot be located with x-rays close to heavy elements; instead, neutron diffraction is needed. We show that, contrary to widespread expectation, hydrogen atoms can be located very accurately using x-ray diffraction, yielding bond lengths involving hydrogen atoms (A-H) that are in agreement with results from neutron diffraction mostly within a single standard deviation. The precision of the determination is also comparable between x-ray and neutron diffraction results. This has been achieved at resolutions as low as 0.8 Å using Hirshfeld atom refinement (HAR). We have applied HAR to 81 crystal structures of organic molecules and compared the A-H bond lengths with those from neutron measurements for A-H bonds sorted into bonds of the same class. We further show in a selection of inorganic compounds that hydrogen atoms can be located in bridging positions and close to heavy transition metals accurately and precisely. We anticipate that, in the future, conventional x-radiation sources at in-house diffractometers can be used routinely for locating hydrogen atoms in small molecules accurately instead of large-scale facilities such as spallation sources or nuclear reactors.

Hydrogen atoms can be located accurately and precisely by x-ray crystallography

PubMed Central

Woińska, Magdalena; Grabowsky, Simon; Dominiak, Paulina M.; Woźniak, Krzysztof; Jayatilaka, Dylan

2016-01-01

Precise and accurate structural information on hydrogen atoms is crucial to the study of energies of interactions important for crystal engineering, materials science, medicine, and pharmacy, and to the estimation of physical and chemical properties in solids. However, hydrogen atoms only scatter x-radiation weakly, so x-rays have not been used routinely to locate them accurately. Textbooks and teaching classes still emphasize that hydrogen atoms cannot be located with x-rays close to heavy elements; instead, neutron diffraction is needed. We show that, contrary to widespread expectation, hydrogen atoms can be located very accurately using x-ray diffraction, yielding bond lengths involving hydrogen atoms (A–H) that are in agreement with results from neutron diffraction mostly within a single standard deviation. The precision of the determination is also comparable between x-ray and neutron diffraction results. This has been achieved at resolutions as low as 0.8 Å using Hirshfeld atom refinement (HAR). We have applied HAR to 81 crystal structures of organic molecules and compared the A–H bond lengths with those from neutron measurements for A–H bonds sorted into bonds of the same class. We further show in a selection of inorganic compounds that hydrogen atoms can be located in bridging positions and close to heavy transition metals accurately and precisely. We anticipate that, in the future, conventional x-radiation sources at in-house diffractometers can be used routinely for locating hydrogen atoms in small molecules accurately instead of large-scale facilities such as spallation sources or nuclear reactors. PMID:27386545

Introducing a New Capability at SSRL: Resonant Soft X-ray Scattering

NASA Astrophysics Data System (ADS)

Lee, Jun-Sik; Jang, Hoyoung; Lu, Donghui; Kao, Chi-Chang

Stanford Synchrotron Radiation Lightsource (SSRL) at SLAC recently developed a setup for the resonant soft x-ray scattering (RSXS). In general, the RSXS technique uniquely probes not only structural information, but also chemical specific information. This is because this technique can explore the spatial periodicities of charge, orbital, spin, and lattice with spectroscopic aspect. Moreover, the soft x-ray range is particularly relevant for a study of soft materials as it covers the K-edge of C, N, F, and O, as well as the L-edges of transition metals and M-edges of rare-earth elements. Hence, the RSXS capability has been regarded as a very powerful technique for investigating the intrinsic properties of materials such as quantum- and energy-materials. The RSXS capability at the SSRL composes of in-vacuum 4-circle diffractometer. There are also the fully motorized sample-motion manipulations. Also, the sample can be cooled down to 25 K via the liquid helium. This capability has been installed at BL 13-3, where the photon source is from elliptically polarized undulator (EPU). Covering the photon energies is from 230 eV to 1400 eV. Furthermore, this EPU system offers more degree of freedoms for controlling x-ray polarizations (linear and circular). Using the advance of controlling x-ray polarization, we can also investigate a morphology effect of local domain/grain in materials. The detailed introduction of the RSXS end-station and several results will be touched in this poster presentation.

Visible light photocatalytic activities of template free porous graphitic carbon nitride-BiOBr composite catalysts towards the mineralization of reactive dyes

NASA Astrophysics Data System (ADS)

Kanagaraj, Thamaraiselvi; Thiripuranthagan, Sivakumar; Paskalis, Sahaya Murphin Kumar; Abe, Hideki

2017-12-01

Template free porous g-C3N4 (pGCN) and flower like bismuth oxybromide catalysts were synthesized by poly condensation and precipitation methods respectively. Various weight percentages of porous GCN-BiOBr composite catalysts (x% pGCN-BiOBr where x = 5, 10, 30, 50 & 70 wt% of pGCN) were synthesized by impregnation method. All the synthesized catalysts were characterized by X-Ray diffractometer, Fourier transform infrared spectrophotometer, BET surface area analyzer, UV Visible diffuse reflectance spectrophotometer, X-Ray photoelectron spectrophotometer, SEM with Energy dispersive X-ray analyzer (SEM/EDAX) and elemental mapping, Transmission electron microscope, Photoluminescence spectrophotometer and Electrochemical impedance. Photocatalytic degradation of all the synthesized catalysts were tested towards the harmful reactive dyes such as reactive blue 198 (RB 198), reactive black 5 (RB 5) and reactive yellow 145 (RY 145) in presence of visible irradiation. Among the catalysts 30% pGCN-BiOBr resulted in the highest photocatalytic activity towards the degradation of all the three dyes in presence of UV, visible and solar irradiations. Kinetics studies on the photocatalytic mineralization of dyes indicated that it followed pseudo first order. HPLC, TOC and COD studies confirm that the dyes are mineralized into CO2, water and mineral salts.

New Developments at the ALS High-Pressure Beamline 12.2.2

NASA Astrophysics Data System (ADS)

Kunz, M.; MacDowell, A. A.; Yan, J.; Beavers, C. C. G.; Doran, A.; Williams, Q. C.

2015-12-01

ALS-beamline 12.2.2 celebrated its 10-year anniversary as a beamline collaboratively operated by the ALS and COMPRES. The anniversary coincided with a major rebuild and expansion of its capabilities for in-situ high-pressure and high-temperature X-ray diffraction. A rebuild of the 12.2.2 laser heating table was completed and commissioned in the past year. The new design relies on a vertically positioned small (~1m x 1m) breadboard that is placed perpendicularly to the incident X-ray beam next to the sample stage. Upstream and downstream viewing-, IR-laser and pyrometry-optics are mounted on opposite surfaces of the breadboard. On-line ruby fluorescence optics including a blue diode laser are also mounted on the upstream surface. The much reduced dimensions of the design lead to smaller mechanical lever arms and thus to a significant suppression of vibrations. This was confirmed in the commissioning phase with high-quality optical images (~ 2 μm resolution) as well as a very stable hotspot in DAC samples. A further optimized pyrometry code was cross-calibrated against thermal expansions of Pt and Ta, and was found to agree with those values within experimental uncertainties. Pyrometry relies on imaging the full hot-spot onto a spectrometer and combining the thus obtained average temperature with an intensity map collected at 700 nm to produce a temperature contour map of the entire sample chamber. Besides axial laser heating, double-sided radial laser heating is also being developed and commissioned. The X-ray source of 12.2.2 makes it an ideal station to focus on high-pressure single crystal diffraction. The present set-up operates parasitically with a single rotation axis on the in-situ laser heating powder diffraction sample stage in concert with a fast (15 fps) amorphous silicon/diode array detector. Although this set-up poses limitations with respect to accessible reciprocal space, high pressure single crystal structure solution and refinements of organic compounds incl. anisotropic displacement parameters have been demonstrated. Imminent development plans aim for the installation of a rugged multi-axis diffractometer on its own dedicated end-station in combination with with a compact fast detector on the 2-theta arm. This will be capable of carrying state of the art wide opening angle DAC's (BX90).

Adsorption enhancement of elemental mercury onto sulphur-functionalized silica gel adsorbents.

PubMed

Johari, Khairiraihanna; Saman, Norasikin; Mat, Hanapi

2014-01-01

In this study, elemental mercury (EM) adsorbents were synthesized using tetraethyl orthosilicate (TEOS) and 3-mercaptopropyl trimethoxysilane as silica precursors. The synthesized silica gel (SG)-TEOS was further functionalized through impregnation with elemental sulphur and carbon disulphide (CS2). The SG adsorbents were then characterized by using scanning electron microscope, Fourier transform infra-red spectrophotometer, nitrogen adsorption/desorption, and energy-dispersive X-ray diffractometer. The EM adsorption of the SG adsorbents was determined using fabricated fixed-bed adsorber. The EM adsorption results showed that the sulphur-functionalized SG adsorbents had a greater Hgo breakthrough adsorption capacity, confirming that the presence of sulphur in silica matrices can improve Hgo adsorption performance due to their high affinity towards mercury. The highest Hgo adsorption capacity was observed for SG-TEOS(CS2) (82.62 microg/g), which was approximately 2.9 times higher than SG-TEOS (28.47 microg/g). The rate of Hgo adsorption was observed higher for sulphur-impregnated adsorbents, and decreased with the increase in the bed temperatures.

An X-Ray Diffractometer for Mineralogical Analysis of Exomars Mission

NASA Astrophysics Data System (ADS)

Marinangeli, L.; Baliva, A.; Critani, F.; Stevoli, A.; Scandelli, L.; Holland, A.; Hutchinson, I.; Nelms, N.; Delhez, R.

2006-12-01

The new results of the Mars Exploration Rovers and the Mars Express mission outline the importance of a correct assessment of the variety of geological contexts to understand the evolution of a habitable environment. The need of having complex scientific payload to perform a broad range of in situ measurements is a necessary step for a successful exobiological exploration. Furthermore, the compositional analysis of the surface samples is of fundamental importance to characterize the geological environments where life could have arisen and their evolution through time. In the last years, there has been a strong interest in Europe to develop a x-ray diffractometer (XRD) for mineralogical analyses of planetary surfaces. The identification of minerals using the diffraction technique is based on the x-ray interference with the geometrical parameters of the crystal lattice allowing an unequivocal recognition of different minerals. An US XRD instrument, CHEMIN, will flight for the first time in the NASA Mars Science Laboratory in 2009. An European XRD design has also been selected for the Pasteur Payload of the ESA ExoMars mission, planned for 2011. The proposed instrument is a miniaturised concept (1 kg) configured in a reflection geometry and will allow the identification of a large spectrum of minerals including those related to the presence of water, key element for the development of life. The complete mineralogical analysis will be performed on very small quantities of powder rock samples, thought analysis of pristine (no grinded) sample can also be achieved with the reflection configuration. Information on the elemental composition of the sample can be roughly estimated by the analysis of the x-ray fluorescence spectrum simultaneously acquired by the detection system. In order to demonstrate the instrument technological readiness for the ExoMars mission, the construction of a demonstrative prototype is on going with ESA funding. Preliminary result of the scientific evaluation of the prototype will be shown to assess the capability of the proposed concept in the identification of rock mineralogy. IRSPS and and Laben are respectively the team science coordinator and the engineering responsible for the instrument development. The detector assembly for the prototype has been developed by UK and discussion for the UK involvement on the future instrument development is on going. Delft is providing scientific contribution for the prototype evaluation.

Online in situ x-ray diffraction setup for structural modification studies during swift heavy ion irradiation

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

Grygiel, C.; Lebius, H.; Bouffard, S.

2012-01-15

The high energy density of electronic excitations due to the impact of swift heavy ions can induce structural modifications in materials. We present an x-ray diffractometer called ALIX (''Analyse en Ligne sur IRRSUD par diffraction de rayons X''), which has been set up at the low-energy beamline (IRRadiation SUD - IRRSUD) of the Grand Accelerateur National d'Ions Lourds facility, to allow the study of structural modification kinetics as a function of the ion fluence. The x-ray setup has been modified and optimized to enable irradiation by swift heavy ions simultaneously to x-ray pattern recording. We present the capability of ALIXmore » to perform simultaneous irradiation-diffraction by using energy discrimination between x-rays from diffraction and from ion-target interaction. To illustrate its potential, results of sequential or simultaneous irradiation-diffraction are presented in this article to show radiation effects on the structural properties of ceramics. Phase transition kinetics have been studied during xenon ion irradiation of polycrystalline MgO and SrTiO{sub 3}. We have observed that MgO oxide is radiation-resistant to high electronic excitations, contrary to the high sensitivity of SrTiO{sub 3}, which exhibits transition from the crystalline to the amorphous state during irradiation. By interpreting the amorphization kinetics of SrTiO{sub 3}, defect overlapping models are discussed as well as latent track characteristics. Together with a transmission electron microscopy study, we conclude that a single impact model describes the phase transition mechanism.« less

Synthesis and magnetic properties of NiFe2-xSmxO4 nanopowder

NASA Astrophysics Data System (ADS)

Hassanzadeh-Tabrizi, S. A.; Behbahanian, Shahrzad; Amighian, Jamshid

2016-07-01

NiFe2-xSmxO4 (x=0.00, 0.05, 0.10 and 0.15) nanopowders were synthesized via a sol-gel combustion route. The structural studies were carried out by X-ray diffractometer, Fourier transform infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. The XRD results confirmed the formation of single-phase spinel cubic structure. The crystallite size decreased with an increase of samarium ion concentration, while lattice parameter and lattice strain increased with samarium substitution. TEM micrographs showed that agglomerated nanoparticles with particle sizes ranging from 35 to 90 nm were obtained. The magnetic studies were carried out using vibrating sample magnetometer. Magnetic measurements revealed that the saturation magnetization (Ms) of NiFe2-xSmxO4 nanoparticles decreases with increasing Sm3+substitution. The reduction of saturation magnetization is attributed to the dilution of the magnetic interaction. The coercivity (Hc) of samples increases by adding samarium.

ALICE—An advanced reflectometer for static and dynamic experiments in magnetism at synchrotron radiation facilities

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

Abrudan, R.; Helmholtz-Zentrum-Berlin for Materials and Energy, 12489 Berlin; Brüssing, F.

2015-06-15

We report on significant developments of a high vacuum reflectometer (diffractometer) and spectrometer for soft x-ray synchrotron experiments which allows conducting a wide range of static and dynamic experiments. Although the chamber named ALICE was designed for the analysis of magnetic hetero- and nanostructures via resonant magnetic x-ray scattering, the instrument is not limited to this technique. The versatility of the instrument was testified by a series of pilot experiments. Static measurements involve the possibility to use scattering and spectroscopy synchrotron based techniques (photon-in photon-out, photon-in electron-out, and coherent scattering). Dynamic experiments require either laser or magnetic field pulses tomore » excite the spin system followed by x-ray probe in the time domain from nano- to femtosecond delay times. In this temporal range, the demagnetization/remagnetization dynamics and magnetization precession in a number of magnetic materials (metals, alloys, and magnetic multilayers) can be probed in an element specific manner. We demonstrate here the capabilities of the system to host a variety of experiments, featuring ALICE as one of the most versatile and demanded instruments at the Helmholtz Center in Berlin-BESSY II synchrotron center in Berlin, Germany.« less

Integrated nonlinear optical imaging microscope for on-axis crystal detection and centering at a synchrotron beamline

PubMed Central

Madden, Jeremy T.; Toth, Scott J.; Dettmar, Christopher M.; Newman, Justin A.; Oglesbee, Robert A.; Hedderich, Hartmut G.; Everly, R. Michael; Becker, Michael; Ronau, Judith A.; Buchanan, Susan K.; Cherezov, Vadim; Morrow, Marie E.; Xu, Shenglan; Ferguson, Dale; Makarov, Oleg; Das, Chittaranjan; Fischetti, Robert; Simpson, Garth J.

2013-01-01

Nonlinear optical (NLO) instrumentation has been integrated with synchrotron X-ray diffraction (XRD) for combined single-platform analysis, initially targeting applications for automated crystal centering. Second-harmonic-generation microscopy and two-photon-excited ultraviolet fluorescence microscopy were evaluated for crystal detection and assessed by X-ray raster scanning. Two optical designs were constructed and characterized; one positioned downstream of the sample and one integrated into the upstream optical path of the diffractometer. Both instruments enabled protein crystal identification with integration times between 80 and 150 µs per pixel, representing a ∼103–104-fold reduction in the per-pixel exposure time relative to X-ray raster scanning. Quantitative centering and analysis of phenylalanine hydroxylase from Chromobacterium violaceum cPAH, Trichinella spiralis deubiquitinating enzyme TsUCH37, human κ-opioid receptor complex kOR-T4L produced in lipidic cubic phase (LCP), intimin prepared in LCP, and α-cellulose samples were performed by collecting multiple NLO images. The crystalline samples were characterized by single-crystal diffraction patterns, while α-cellulose was characterized by fiber diffraction. Good agreement was observed between the sample positions identified by NLO and XRD raster measurements for all samples studied. PMID:23765294

X-ray line profile analysis of BaTiO3 thin film prepared by sol-gel deposition

NASA Astrophysics Data System (ADS)

Ooi, Zeen Vee; Saif, Ala'eddin A.; Wahab, Yufridin; Jamal, Zul Azhar Zahid

2017-04-01

Barium titanate (BaTiO3) thin film was prepared using sol-gel method and spun-coated on SiO2/Si substrate. The phase and crystallinity of the synthesized film were identified using X-ray diffractometer (XRD), which scanned at the range of 20° to 60°. The phase and lattice parameters of the fabricated film were extracted from the recorded XRD patterns using lattice geometry equations. The crystallite size and lattice strain were determined using X-ray line profile analysis (XLPA) with various approaches. The Scherrer equation was applied to the perovskite peaks of the film to explore the size contribution on the peak broadening. Meanwhile, the Williamson-Hall and size-strain plot (SSP) methods were used to review two main independent contributions, i.e. crystallite sizes and lattice strain, on the X-ray line broadening. From the analysis, it is found that Scherrer method gives smallest crystallite size value by ignoring the strain-induced broadening effect. On the other hand, Williamson-Hall and SSP graphs revealed the existence of the lattice strain within the film, which contributes to the broadening in the Bragg peak. The results that analyzed via both techniques show a linear trend with all data points fitted. However, result obtained from SSP method gives better settlement due to the best fit of the data.

The effect of milling time and sintering temperature on Mn, Ti substituted barium hexaferrite nanoparticle

NASA Astrophysics Data System (ADS)

Yustanti, Erlina; Manaf, Azwar

2018-04-01

Barium hexaferrite (BaO.6Fe2O3/BaFe12O19) is a permanent magnetic material and microwave absorbing material. The value of microwave absorption can be increased through the engineering of the material structure, while the reduction of crystallite and particle size up to nanometer results device performance improvement to be superior. In this research, the structural engineering through mechanical alloying and crystallite size reduction through high power ultrasonic irradiation will be explained. Mixing and alloying of Sigma Aldrich BaCO3, Fe2O3, MnCO3, TiO2 p.a 99% precursor material used ball mill with powder ratio of vial at 1:10. Mechanical alloying for 60 hours at 160 rpm produced amorphous material. The process of the crystalline embryo nucleation for 4 hours produced multicrystalline material at a sinter temperature of 1100°C. Phase analysis of the mechanical alloying result using x-ray diffractometer was confirmed either the formation of BaO.6Fe2-xMnx/2Tix/2O3 (x=0.5) single phase. Multicrystalline powder of BaO.6Fe2-xMnx/2Tix/2O3 (x=0.5) was obtained through 20 hours hand grinding and re-milling to bulk sample. Crystallite size reduction in the analysis was conducted through particle density variation in ultrasonic reactor and variation of the increase in ultrasonic time. Increase in milling time up to 60 hours produced fragmenting so that particle size reduction from 18.8 µm to 0.9 µm was occurred. The 12-h ultrasonic irradiation at a frequency of 20 kHz amplitude of 60 µm produced a crystallite-size reduction up to 18 nm at a 10 g/L particle density.

Adsorption of Benzoic Acid in Aqueous Solution by Bagasse Fly Ash

NASA Astrophysics Data System (ADS)

Suresh, S.

2012-09-01

This paper reports the studies on the benzoic acid (BA) onto bagasse fly ash (BFA) was studied in aqueous solution in a batch system. Physico-chemical properties including surface area, surface texture of the GAC before and after BA adsorption onto BFA were analysed using X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The optimum initial pH for the adsorption of BA was found to be 5.56. The adsorbent dose was 10 g/l for BFA and the equilibrium time 8 h of reaction. Pseudo first and second order models were used to find the adsorption kinetics. It was found that intraparticle diffusion played important role in the adsorption mechanisms of BA and the adsorption kinetics followed pseudo-second order kinetic model rather than the pseudo first order kinetic model. Isotherm data were generated for BA solution having initial concentrations of BA in the range of 10-200 mg/l for the BFA dosage of 10 g/l at temperatures of 288, 303, and 318 K. The adsorption of BA onto BFA was favorably influenced by an increase in temperature. Equilibrium data were well represented by the Redlich-Peterson isotherm model. Values of the change in entropy ( ΔS 0), heat of adsorption ( ΔH 0) for adsorption of BA on BFA was found to be 120.10 and 19.61 kJ/mol respectively. The adsorption of BA onto BFA was an endothermic reaction. Desorption of BA from BFA was studied by various solvents method. Acetic acid was found to be a better eluant for desorption of BA with a maximum desorption efficiency of 55.2 %. Owing to its heating value, spent BFA can be used as a co-fuel for the production of heat in boiler furnaces.

Microstructure and magnetic behavior of Mn doped GeTe chalcogenide semiconductors based phase change materials

NASA Astrophysics Data System (ADS)

Adam, Adam Abdalla Elbashir; Cheng, Xiaomin; Abuelhassan, Hassan H.; Miao, Xiang Shui

2017-06-01

Phase-change materials (PCMs) are the most promising candidates to be used as an active media in the universal data storage and spintronic devices, due to their large differences in physical properties of the amorphous-crystalline phase transition behavior. In the present study, the microstructure, magnetic and electrical behaviors of Ge0.94Mn0.06Te thin film were investigated. The crystallographic structure of Ge0.94Mn0.06Te thin film was studied sing X-ray diffractometer (XRD) and High Resolution Transmission Electron Microscope (HR-TEM). The XRD pattern showed that the crystallization structure of the film was rhombohedral phase for GeTe with a preference (202) orientation. The HR-TEM image of the crystalline Ge0.94Mn0.06Te thin film demonstrated that, there were two large crystallites and small amorphous areas. The magnetization as a function of the magnetic field analyses of both amorphous and crystalline states showed the ferromagnetic hysteretic behaviors. Then, the hole carriers concentration of the film was measured and it found to be greater than 1021 cm-3 at room temperature. Moreover, the anomalous of Hall Effect (AHE) was clearly observed for the measuring temperatures 5, 10 and 50 K. The results demonstrated that the magnitude of AHE decreased when the temperature was increasing.

Magnesium and cadmium containing Heusler phases REPd2Mg, REPd2Cd, REAg2Mg, REAu2Mg and REAu2Cd

NASA Astrophysics Data System (ADS)

Johnscher, Michael; Stein, Sebastian; Niehaus, Oliver; Benndorf, Christopher; Heletta, Lukas; Kersting, Marcel; Höting, Christoph; Eckert, Hellmut; Pöttgen, Rainer

2016-02-01

Twenty-eight new Heusler phases REPd2Mg, REPd2Cd, REAg2Mg, REAu2Mg and REAu2Cd with different rare earth elements were synthesized from the elements in sealed niobium ampoules in a water-cooled sample chamber of an induction furnace. The samples were characterized by powder X-ray diffraction. The cell volumes show the expected lanthanide contraction. The structures of YPd2Cd, GdPd2Cd, GdAu2Cd, Y1.12Ag2Mg0.88 and GdAg2Mg were refined based on single crystal diffractometer data. The magnetic properties were determined for fifteen phase pure samples. LuAu2Mg is a weak Pauli paramagnet with a susceptibility of 1.0(2) × 10-5 emu mol-1 at room temperature. The remaining samples show stable trivalent rare earth ions and most of them order magnetically at low temperatures. The ferromagnet GdAg2Mg shows the highest ordering temperature of TC = 98.3 K. 113Cd and 89Y MAS NMR spectra of YAu2Cd and YPd2Cd confirm the presence of unique crystallographic sites. The resonances are characterized by large Knight shifts, whose magnitude can be correlated with electronegativity trends.

Synthesis and characterization of nanometric zinc oxide for a stationary phase in liquid chromatography

NASA Astrophysics Data System (ADS)

Gordillo-Delgado, F.; Soto-Barrera, C. C.; Plazas-Saldaña, J.

2017-01-01

The increasing demand for equipment to remove organic compounds in industry and research activity has led to evaluate nanometric zinc oxide (ZnO). In this work, we present the ZnO nanoparticles synthesis for reusing of discarded columns, as a low-cost alternative. The compound was obtained by sol-gel technique using zinc chloride and sodium hydroxide as precursors and a drying temperature of 169°C. An X-ray diffractometer was used to estimate the average particle size at 20.3±0.2nm the adsorption capacity was 0.0144L/g and the chemical resistance was tested with HCl and NaOH. The ZnO nanopowder was packed with 100psi pressure in an empty C-18 column cavity. The column packing resolution was evaluated using a high performance liquid chromatographer (HPLC-Thermo Scientific Dionex UltiMate 3000); using a caffeine standard, the following parameters were established: solvent flow: 1.2mL/min, average column temperature: 40°C, running time: 10 minutes, mobile phase acetonitrile-water composition (9:1). These results validate the potential of ZnO nanopowder as a column packing material in HPLC technique.

Characterization and Surface Treatment of Materials Used in MADEAL S.A. Industry Productive Process of Rims by Plasma Assisted Repetitive Pulsed Arcs Technique

NASA Astrophysics Data System (ADS)

Jiménez, H.; Salazar, V. H.; Devia, A.; Jaramillo, S.; Velez, G.

2006-12-01

A study of materials used in the molds production to aluminium rims manufacture in the MADEAL S.A. factory was carried out for apply a plasma assisted surface treatment consists in growing TiAlN hard coatings that it protects this molds in the productive process. This coating resists high oxidation temperatures, of the other of 800 °C, high hardness (2800 Vickers) and low friction coefficient. A plasma assisted repetitive pulsed arcs mono-evaporator system was used in the grow of the TiAlN coatings, the TiAlN target is a sinterized 50% Ti and 50% Al, in the substrate they were used two types of steel that compose the molds injection pieces for the rims production. These materials were subjected to linear and fluctuating thermal changes in the Bruker axs X-Ray diffractometer temperature chamber, what simulated the molds thermal variation in the rims production process and they were compared with TiAlN coatings subjected to same thermal changes. The Materials characterization, before and later of thermal process, was carried out using XRD, SPM and EDS techniques, to analyze the crystallographic, topographic and chemical surface structure behaviours.

A New High-Flux Chemical and Materials Crystallography Station at the SRS Daresbury. 1. Design, Construction and Test Results.

PubMed

Cernik, R J; Clegg, W; Catlow, C R; Bushnell-Wye, G; Flaherty, J V; Greaves, G N; Burrows, I; Taylor, D J; Teat, S J; Hamichi, M

1997-09-01

A new single-crystal diffraction facility has been constructed on beamline 9 of the SRS at Daresbury Laboratory for the study of structural problems in chemistry and materials science. The station utilizes up to 3.8 mrad horizontally from the 5 T wiggler magnet which can be focused horizontally and vertically. The horizontal focusing is provided by a choice of gallium-cooled triangular bent Si (111) or Si (220) monochromators, giving a wavelength range from 0.3 to 1.5 A. Focusing in the vertical plane is achieved by a cylindrically bent zerodur mirror with a 300 mum-thick palladium coating. The station is equipped with a modified Enraf-Nonius CAD-4 four-circle diffractometer and a Siemens SMART CCD area-detector system. High- and low-temperature facilities are available to cover the temperature range from about 80 to 1000 K. Early results on test compounds without optimization of the beam optics demonstrate that excellent refined structures can be obtained from samples giving diffraction patterns too weak to be measured with conventional laboratory X-ray sources, fulfilling a major objective of the project.

Single-step uncalcined N-TiO2 synthesis, characterizations and its applications on alachlor photocatalytic degradations

NASA Astrophysics Data System (ADS)

Suwannaruang, Totsaporn; Wantala, Kitirote

2016-09-01

The aims of this research were to synthesize nitrogen doped TiO2 (N-TiO2) photocatalysts produced by hydrothermal technique and to test the degradation performance of alachlor by photocatalytic process under UV irradiations in the effect of aging temperature and time in the preparation process. The characterizations of synthesized TiO2 such as specific surface area, particle size, phase structure and elements were analyzed by using the Brunauer-Emmett-Teller (BET) technique, Transmission Electron Microscopy (TEM), X-ray Diffractometer (XRD) and Energy Dispersive X-ray spectrometer (EDX), respectively. The Central Composite Design (CCD) was used to design the experiment to determine the optimal condition, main effects and their interactions by using specific surface area, percent alachlor removal and observed first-order rate constant as responses. The kinetic reactions of alachlor degradation were explained by using Langmuir-Hinshelwood expression to confirm the reaction took place on the surface of photocatalyst. The results showed that the effect of aging temperatures was significant on surface area, whereas aging time was insignificant. Additionally, the square term of aging temperature and interaction term were shown significant on the specific surface area as well. The highest specific surface area from response surface at aging temperature between 150-175 °C and aging time between 6-13 h was found in a range of 100-106 m2/g. The average particle size of TiO2 was similar to crystallite size. Therefore, it can be concluded that one particle has only one crystal. The element analysis has shown 10% of nitrogen in TiO2 structure that the energy band-gap about 2.95 eV was found. Although, the effects of aging temperature and time on percent alachlor removal and observed first-order rate constants were insignificant, both terms were significant in term of the square for alachlor photocatalytic degradation. The optimal condition of both responses was achieved at an aging temperature of 145 °C and aging time of 12 h.

Etude de la nitruration carbothermique du dioxyde de hafnium par diffraction X à haute température

NASA Astrophysics Data System (ADS)

Pialoux, A.

1993-03-01

The carbothermal reduction of hafnium dioxide under atmospheric level nitrogen pressure has been investigated using a graphite resistance high temperature X-ray diffractometer up to around 2300 K. A carbon transfer reaction through the gaseous phase (N 2, CO/CO 2) is shown to precede, then to compete the direct reduction of the hafnium oxide by the graphite in pure nitrogen. A complex mechanism has been found that accounts for the formation of hafnium dioxynitride and possibly of three other hafnium oxynitrides, then of hafnium mononitride and hafnium monocarbonitride, along two different steps between 1613 and 1923 K. An evaluation has been made concerning the composition of these γ 1- HfO 2-xN x/2□ x/2 (CaF 2-type structure), γ 2- Hf 7O 11N 2, γ 3- Hf 7O 8N 4 (rhombohedral), γ 4- Hf 2ON 2 (Mn 2O 3-type structure), HfN and HfN 1-zC z (NaCl-type structure) phases, considering the variations of their lattice parameters and the available data in the literature, especially on the isomorphous compounds of zirconium. It must be emphasized the new γ 1- HfO 2-xN x/2 phase, the dilatation of which is linear ( overlineα = 12×10 -6K -1), shows a constant composition from 2158 down to 1473 K (x ≈ 0,2). But under 1473 K, inevitably, the hafnium dioxynitride disappears, and poorly crystallized monoclinic αHfO 2 and rhombohedral γ 2- Hf 7O 11N 2 are formed.

Synthesis of Zn1-xCdxO Nanoparticles by Co-Precipitation: Structural, Optical and Photodetection Analysis

NASA Astrophysics Data System (ADS)

Jacob, Anju Anna; Balakrishnan, L.; Meher, S. R.; Shambavi, K.; Alex, Z. C.

Zinc oxide (ZnO) is a wide bandgap semiconductor with excellent photoresponse in ultra-violet (UV) regime. Tuning the bandgap of ZnO by alloying with cadmium can shift its absorption cutoff wavelength from UV to visible (Vis) region. Our work aims at synthesis of Zn1-xCdxO nanoparticles by co-precipitation method for the fabrication of photodetector. The properties of nanoparticles were analyzed using X-ray diffractometer, UV-Vis spectrometer, scanning electron microscope and energy dispersive spectrometer. The incorporation of cadmium without altering the wurtzite structure resulted in the red shift in the absorption edge of ZnO. Further, the photoresponse characteristics of Zn1-xCdxO nanopowders were investigated by fabricating photodetectors. It has been found that with Cd alloying the photosensitivity was increased in the UVA-violet as well in the blue region.

Preparation of Er3+:Y3Al5O12/WO3-KNbO3 composite and application in treatment of methamphetamine under ultrasonic irradiation.

PubMed

Zhang, Hongbo; Huang, Yingying; Li, Guanshu; Wang, Guowei; Fang, Dawei; Song, Youtao; Wang, Jun

2017-03-01

Er 3+ :Y 3 Al 5 O 12 /WO 3 -KNbO 3 composite powder as an effective sonocatalyst was prepared via collosol-gelling-hydrothermal and high-temperature calcination methods. The textures of materials were observed by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). In order to estimate the sonocatalytic activity of Er 3+ :Y 3 Al 5 O 12 /WO 3 -KNbO 3 composite powder, the sonocatalytic degradation of methamphetamine (MAPA) was performed. Furthermore, the influences of mass ratio of WO 3 and KNbO 3 , ultrasonic irradiation time, catalyst addition amount, initial methamphetamine (MAPA) concentration and used times on the sonocatalytic degradation of methamphetamine (MAPA) caused by Er 3+ :Y 3 Al 5 O 12 /WO 3 -KNbO 3 composite powder were investigated by using gas chromatography. Under optimal conditions of 1.00g/L Er 3+ :Y 3 Al 5 O 12 /WO 3 -KNbO 3 addition amount and 10.00mg/L methamphetamine (MAPA) initial concentration, 68% of methamphetamine (MAPA) could be removed after 150min ultrasonic irradiation. The experimental results showed that the Er 3+ :Y 3 Al 5 O 12 /WO 3 -KNbO 3 as sonocatalyst displayed an excellent sonocatalytic activity in degradation of methamphetamine (MAPA) under ultrasonic irradiation. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation, Structural Characterization and Magnetic Properties of La-SUBSTITUTED co Ferrites via a Modified Citrate Precursor Route

NASA Astrophysics Data System (ADS)

Ai, Lunhong; Jiang, Jing

CoLaxFe2-xO4 (x = 0.00, 0.05 and 0.1) nanoparticles were prepared simply by a modified citrate precursor route. Effects of La-substituting level on the their magnetic properties were investigated on the basis of the structural analysis. The thermal evolution of the precursor, as well as the microstructure of as-prepared products were studied by means of a thermogravimetric analyzer (TGA), X-ray diffractometer (XRD) and Fourier transform infrared (FTIR) spectrometer. The magnetic properties of the as-prepared samples were measured using a vibrating sample magnetometer (VSM). It was found that the magnetic properties were dependent on many factors such as La-substituting level, particle size and microstructure. The observed saturation magnetization decreased with increasing La content, whereas coercivity exhibited reverse behavior.

Synthesis and characterization of γ-Fe2O3 NPs on silicon substrate for power device application

NASA Astrophysics Data System (ADS)

Hussein Nurul Athirah, Abu; Bee Chin, Ang; Yew Hoong, Wong; Boon Hoong, Ong; Aainaa Aqilah, Baharuddin

2018-06-01

Maghemite nanoparticles (γ-Fe2O3 NPs) were synthesized using Massart procedure. The formation reaction were optimized by varying the concentration of ferric nitrate solution (Fe(NO3)3) (0.1, 0.3, 0.5, 0.7 and 1.0 M). All samples were characterized by means of x-ray Diffractometer (XRD), Raman Spectroscopy, Transmission Electron Microscope (TEM) and Alternating Gradient Magnetometer (AGM). The smallest size of the NPs were chosen to be deposited on Silicon (100) substrate by spin coating technique. Annealing process of the samples were performed in Argon ambient at different temperatures (600, 700, 800 and 900°) for 20 min. Metal-oxide-semiconductor capacitors were then fabricated by depositing Aluminium as the gate electrode. The effect of the annealing process on the structural and electrical properties of γ-Fe2O3 NPs thin film were investigated. The structural properties of the deposited thin film were evaluated by XRD analysis, Atomic Force Microscopy (AFM) and Raman Analysis. On the other hand, the electrical properties was conducted by current-voltage analysis. It was revealed that the difference in the annealing temperature affect the grain size, surface roughness, distribution of the nanoparticles as well as the electrical performance of the samples where low annealing temperature (600 °C) gives low leakage current while high annealing temperature (900 °C) gives high electrical breakdown.

Estimation of Crystallinity of Nifedipine-Polyvinylpyrrolidone Solid Dispersion by Usage of Terahertz Time-Domain Spectroscopy and of X-Ray Powder Diffractometer.

PubMed

Takeuchi, Issei; Shimakura, Kemmaro; Kuroda, Hideki; Nakajima, Takehisa; Goto, Satoru; Makino, Kimiko

2015-12-01

Crystalline state of pharmaceutical materials is of great importance in preparation of pharmaceutics, because their physicochemical properties affect bioavailability, quality of products, therapeutic level and manufacturing process. In this study, we have estimated time-dependent changes of nifedipine in nifedipine-polyvinylpyrrolidone (PVP) solid dispersion by measuring terahertz time-domain spectroscopy (THz-TDS) and by X-ray powder diffractometry (XRPD), and compared their correlativity. Crystallinity of nifedipine-PVP solid dispersion was changed by storing the amorphous sample at 25°C-75°C and relative humidity of over 80% for 0.25-24.00 h. To compare the results of two types of measurements, we have used a general method of linear regression analysis. Crystallinities estimated using THz-TDS were plotted on the x-axis and that of XRPD were on the y-axis. From the result of the calculation, the correlativity of them was confirmed. THz-TDS has the capability of becoming the replacement of XRPD. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Effect Of Neodymium Substitution In Structural Characteristics Of Magnesium Ferrite

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

Thankachan, Smitha; Binu, P. J.; Xavier, Sheena

2011-10-20

The effect of Nd{sup 3+} substitution on the structural properties of Magnesium ferrite was studied in the series MgNd{sub x}Fe{sub 2-x}O{sub 4}, where x = 0 to 0.3 in steps of 0.05. The series was prepared by sol-gel technique which is one of the novel technique to prepare nanosized samples. Structural characterization was done using X-ray diffractometer and Fourier Transform Infrared Spectrometer. XRD analysis reveals the prepared samples are single phasic till x = 0.2. From x0 = .25, a secondary phase of iron neodymium oxide appears along with the spinel phase. Particle size calculation shows the prepared samples aremore » in the 9nm to 11 nm regime. Lattice parameter was found to increase with concentration of Nd. XRD and FTIR analysis confirmed spinel structure of the prepared samples. XRF result shows the expected composition of prepared samples. The frequency dependence of the dielectric constant in the range 100 Hz--120MHz was also studied« less

Microwave Absorption Properties of La0.8Ca0.2-xAgxMnO3 (x=0.05; x=0.15) Synthesized by Sol-Gel Method

NASA Astrophysics Data System (ADS)

Kurniawan, B.; Laksmi, W.; Sahara, N. A.

2018-04-01

Microwave absorption properties of La0.8Ca0.2-xAgxMnO3 (x= 0.05; 0.15) is reported in this paper. Lanthanum manganite materials was reported as a potential absorber material [1][2][3]. In this paper, the material was synthesized by sol-gel method, calcined at 550°C, and sintered at 900°C. The material was characterized by X-Ray Diffractometer (XRD), and we found that the materials were single phased. Through SEM-EDS characterization it is found that the materials have compositional purity. The resistivity of the materials is obtained by four point probe method, and it is shown that Ag doped decreases the resistivity of the materials. Reflection loss of La0.8Ca0.15Ag0.05MnO3 reaches -4.470 dB and La0.8Ca0.05Ag0.15MnO3 reaches - 7.953 dB.

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

Takagi, H., E-mail: takagih@post.kek.jp; Igarashi, N.; Mori, T.

BL-6A has been operational since 2011 as a small angle X-ray scattering (SAXS) beamline at the Photon Factory (PF), and beginning in 2013 its old components and systems, which were mainly inside the experimental hutch, have been extensively updated. Both the vacuum-passes located between the sample stage and the detector and the fixed surface plate have been replaced by a new semi-automatic diffractometer. These upgrades allow simultaneous SAXS/WAXS experiments and grazing-incidence small angle X-ray scattering (GISAXS) measurements to be conducted. The hybrid pixel detector PILATUS3 1M is installed for SAXS, and PILATUS 100K is available as a WAXS detector. Additionally,more » a pinhole equipped with a micro-ion chamber is available to realize a lower-background and higher-resolution of low angles. Moreover, in a simultaneous SAXS/WAXS experiment, we developed a new beam stop with an embedded photodiode. Thus, BL-6A has evolved into a multipurpose beamline capable of dealing with various types of samples and experimental techniques.« less

Optical, Fluorescence with quantum analysis of hydrazine (1, 3- Dinitro Phenyl) by DFT and Ab initio approach

NASA Astrophysics Data System (ADS)

Cecily Mary Glory, D.; Sambathkumar, K.; Madivanane, R.; Velmurugan, G.; Gayathri, R.; Nithiyanantham, S.; Venkatachalapathy, M.; Rajkamal, N.

2018-07-01

Experimental and computational study of molecular structure, vibrational and UV-spectral analysis of Hydrazine (1, 3- Dinitrophenyl) (HDP) derivatives. The crystal was grown by slow cooling method and the crystalline perfection of single crystals was evaluated by high resolution X-ray diffractometry (HRXRD) using a multicrystal X-ray diffractometer. Fluorescence, FT-IR and FT-Raman spectra of HDP crystal were recorded. The assignments of the vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) followed by scaled quantum force field methodology (SQMFF). NMR studies have confirmed respectively the crystal structure and functional groups of the grown crystal. The energy and oscillator strength calculated by Time-Dependent Density Functional Theory (TD-DFT) result complements the experimental findings. The calculated MESP, UV, HOMO-LUMO energies show that charge transfer done within the molecule. And various thermodynamic parameters are studied. Fukui determines the local reactive site of electrophilic, nucleophilic, descriptor.

Ultrastructural and elemental analysis of sialoliths and their comparison with nephroliths.

PubMed

Rakesh, Nagaraju; Bhoomareddy Kantharaj, Yashoda Devi; Agarwal, Manjushree; Agarwal, Kunal

2014-02-01

Sialoliths are common in the submandibular gland and its duct system, although their exact cause of formation is still a matter of debate. The aims of this study were to: (a) analyze sialoliths ultrastructurally, and to determine the role of foreign bodies or organic materials in the formation of sialolith nuclei; and (b) compare nephroliths with sialoliths ultrastructurally. Three sialoliths and two nephroliths were analyzed ultrastructurally by a scanning electron microscope and X-ray diffractometer. The main structures of the sialoliths were found to be hydroxyapatite crystals. No organic cores were observed in the central parts of the sialoliths. In nephroliths, calcium oxalate, calcium phosphate, and struvite crystals were found. The energy-dispersive X-ray microanalysis found that sialoliths and nephroliths were predominantly composed of elements comprising calcium, phosphorous, magnesium, sodium, chloride, silicon, iron, and potassium. Sialoliths in the submandibular salivary glands might form secondary to sialadenitis, but not via a luminal organic nidus. © 2014 Wiley Publishing Asia Pty Ltd.

Luminescence properties of Eu 3+ and Sm 3+ coactivated Gd(III) tungstate phosphor for light-emitting diodes

NASA Astrophysics Data System (ADS)

Wei, Qiong; Chen, Donghua

2009-09-01

Rare-earth ions coactivated red phosphors Gd 0.2RE 1.8(WO 4) 3 (RE=Eu 3+ and Sm 3+) were synthesized by conventional solid-state reaction using boric acid as a flux agent. The samples were characterized by X-ray diffractometer (XRD), energy-dispersive X-ray spectrometer (EDS) and luminescence spectrometer (LS). The results showed that the Eu-Sm system exhibits higher emission intensity than those of the Eu single-doped system and Sm separate-doped system under ultraviolet (UV) radiation. Samarium(III) ions are effective in broadening and strengthened absorptions around 400 nm. Furthermore, it exhibits enhanced luminescence emission. when the mole ratio of boric acid is about 0.16, the luminescence capability is optimum. Two strongest lines at ultraviolet (394 nm) and blue (465 nm) in excitation spectra of these phosphors match well with the output wavelengths of UV and blue GaN-based light-emitting diodes (LEDs) chips.

Synthesis of BiOCl nanosheets with oxygen vacancies for the improved photocatalytic properties

NASA Astrophysics Data System (ADS)

Cai, Yujie; Li, Dongya; Sun, Jingyu; Chen, Mengdie; Li, Yirui; Zou, Zhongwei; Zhang, Hua; Xu, Haiming; Xia, Dongsheng

2018-05-01

The square-sharped BiOCl nanosheets with oxygen vacancies were successfully synthesized via a facile hydrothermal route using xylitol as surfactant. The as-prepared BiOCl samples were characterized by Powder X-ray Diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), UV-Vis diffuse reflectance spectra (DRS), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS) and Electron spin resonance (ESR). The as-prepared samples were phase-pure with the width and the thickness were about 50-400 nm and 20-50 nm respectively. Besides, the photodegradation performances showed the BiOCl nanosheets with 0.1 g concentration of xylitol (BOC-1) had the best photocatalytic activity under visible light due to its special polycrystalline structure, grain boundary and an optimum concentration of oxygen vacancies. The h+ and radO2- were the two main active species during the photocatalytic process and the possible photocatalytic mechanism was proposed.

Experiments on planetary ices at UCL

NASA Astrophysics Data System (ADS)

Grindrod, P. M.; Fortes, A. D.; Wood, I. G.; Dobson, D.; Sammonds, P. R.; Stone-Drake, L.; Vocadlo, L.

2007-08-01

Using a suite of techniques and equipment, we conduct several different types of experiments on planetary ices at UCL. Samples are prepared in the Ice Physics Laboratory, which consists of a 5 chamber complex of inter-connected cold rooms, controllable from +30 to -30 deg C. Within this laboratory we have a functioning triaxial deformation cell operating at low temperature (down to -90 deg C) and high pressures (300 MPa), an Automatic Ice Fabric Analyser (AIFA) and a low-temperature microscope with CCD output. Polycrystalline samples, 40mm diameter by 100mm long, are compressed in the triaxial rig with a confining pressure; single crystal specimens are compressed in a separate uniaxial creep rig which operates at zero confining pressure for surface studies. A cold stage is also available for study of ice microstructural studies on our new Jeol JSM-6480LV SEM, which also allows tensile, compression and/or bending tests, with load ranges from less than 2N to 5000N. Finally, we also use a cold stage on a new PANalytical, X'pert PRO MPD, high resolution powder diffractometer to study the structure and phase behaviour of icy materials. Recent highlights of our work include: (1) derivation of a manufacturing process for methane clathrate at low temperatures, analysed in the X-Ray Diffraction Laboratory, for future rheological experiments, (2) analysed the growth behaviour of MS11, (3) refurbished and commenced calibration tests on the triaxial deformation cell using ice Ih, and (4) performed creep tests on gypsum and epsomite using the single crystal deformation cell. Further experiments will build on these preliminary results.

Amorphous Analogs of Martian Global Soil: Pair Distribution Function Analyses and Implications for Scattering Models of Chemin X-ray Diffraction Data

NASA Technical Reports Server (NTRS)

Achilles, C. N.; Bish, D. L.; Rampe, E. B.; Morris, R. V.

2015-01-01

Soils on Mars have been analyzed by the Mars Exploration Rovers (MER) and most recently by the Mars Science Laboratory (MSL) rover. Chemical analyses from a majority of soil samples suggest that there is a relatively uniform global soil composition across much of the planet. A soil site, Rocknest, was sampled by the MSL science payload including the CheMin X-ray diffractometer and the Alpha Particle X-ray Spectrometer (APXS). Che- Min X-ray diffraction (XRD) data revealed crystalline phases and a broad, elevated background, indicating the presence of amorphous or poorly ordered materials (Fig 1). Based on the chemical composition of the bulk soil measured by APXS and the composition of crystalline phases derived from unit-cell parameters determined with CheMin data, the percentages of crystalline and amorphous phases were calculated at 51% and 49%, respectively. Attempts to model the amorphous contribution to CheMin XRD patterns were made using amorphous standards and full-pattern fitting methods and show that the broad, elevated background region can be fitted by basaltic glass, allophane, and palagonite. However, the modeling shows only that these phases have scattering patterns similar to that for the soil, not that they represent unique solutions. Here, we use pair distribution function (PDF) analysis to determine the short-range order of amorphous analogs in martian soils and better constrain the amorphous material detected by CheMin.

Surface modifications of AISI 420 stainless steel by low energy Yttrium ions

NASA Astrophysics Data System (ADS)

Nassisi, Vincenzo; Delle Side, Domenico; Turco, Vito; Martina, Luigi

2018-01-01

In this work, we study surface modifications of AISI 420 stainless steel specimens in order to improve their surface properties. Oxidation resistance and surface micro-hardness were analyzed. Using an ion beam delivered by a Laser Ion Source (LIS) coupled to an electrostatic accelerator, we performed implantation of low energy yttrium ions on the samples. The ions experienced an acceleration passing through a gap whose ends had a potential difference of 60 kV. The gap was placed immediately before the samples surface. The LIS produced high ions fluxes per laser pulse, up to 3x1011 ions/cm2, resulting in a total implanted flux of 7x1015 ions/cm2. The samples were characterized before and after ion implantation using two analytical techniques. They were also thermally treated to investigate the oxide scale. The crystal phases were identified by an X-ray diffractometer, while the micro-hardness was assayed using the scratch test and a profilometer. The first analysis was applied to blank, implanted and thermally treated sample surface, while the latter was applied only to blank and implanted sample surfaces. We found a slight increase in the hardness values and an increase to oxygen resistance. The implantation technique we used has the advantages, with respect to conventional methods, to modify the samples at low temperature avoiding stray diffusion of ions inside the substrate bulk.

Room Temperature Tunable Multiferroic Properties in Sol-Gel-Derived Nanocrystalline Sr(Ti1−xFex)O3−δ Thin Films

PubMed Central

Wang, Yi-Guang; Liu, Qiu-Xiang; Jiang, Yan-Ping; Jiang, Li-Li

2017-01-01

Sr(Ti1−xFex)O3−δ (0 ≤ x ≤ 0.2) thin films were grown on Si(100) substrates with LaNiO3 buffer-layer by a sol-gel process. Influence of Fe substitution concentration on the structural, ferroelectric, and magnetic properties, as well as the leakage current behaviors of the Sr(Ti1−xFex)O3−δ thin films, were investigated by using the X-ray diffractometer (XRD), atomic force microscopy (AFM), the ferroelectric test system, and the vibrating sample magnetometer (VSM). After substituting a small amount of Ti ion with Fe, highly enhanced ferroelectric properties were obtained successfully in SrTi0.9Ti0.1O3−δ thin films, with a double remanent polarization (2Pr) of 1.56, 1.95, and 9.14 μC·cm−2, respectively, for the samples were annealed in air, oxygen, and nitrogen atmospheres. The leakage current densities of the Fe-doped SrTiO3 thin films are about 10−6–10−5 A·cm−2 at an applied electric field of 100 kV·cm−1, and the conduction mechanism of the thin film capacitors with various Fe concentrations has been analyzed. The ferromagnetic properties of the Sr(Ti1−xFex)O3−δ thin films have been investigated, which can be correlated to the mixed valence ions and the effects of the grain boundary. The present results revealed the multiferroic nature of the Sr(Ti1−xFex)O3−δ thin films. The effect of the annealing environment on the room temperature magnetic and ferroelectric properties of Sr(Ti0.9Fe0.1)O3−δ thin films were also discussed in detail. PMID:28885579

Defect structure of epitaxial layers of III nitrides as determined by analyzing the shape of X-ray diffraction peaks

NASA Astrophysics Data System (ADS)

Kyutt, R. T.

2017-04-01

The shape of X-ray diffraction epitaxial layers with high dislocation densities has been studied experimentally. Measurements with an X-ray diffractometer were performed in double- and triple-crystal setups with both Cu K α and Mo K α radiation. Epitaxial layers (GaN, AlN, AlGaN, ZnO, etc.) with different degrees of structural perfection grown by various methods on sapphire, silicon, and silicon carbide substrates have been examined. The layer thickness varied in the range of 0.5-30 μm. It has been found that the center part of peaks is well approximated by the Voigt function with different Lorentz fractions, while the wing intensity drops faster and may be represented by a power function (with the index that varies from one structure to another). A well-marked dependence on the ordering of dislocations was observed. The drop in intensity in the majority of structures with a regular system and regular threading dislocations was close to the theoretically predicted law Δθ-3; the intensity in films with a chaotic distribution decreased much faster. The dependence of the peak shape on the order of reflection, the diffraction geometry, and the epitaxial layer thickness was also examined.

Structural and optical properties of Na-doped ZnO films

NASA Astrophysics Data System (ADS)

Akcan, D.; Gungor, A.; Arda, L.

2018-06-01

Zn1-xNaxO (x = 0.0-0.05) solutions have been synthesized by the sol-gel technique using Zinc acetate dihydrate and Sodium acetate which were dissolved into solvent and chelating agent. Na-doped ZnO nanoparticles were obtained from solutions to find phase and crystal structure. Na-doped ZnO films have been deposited onto glass substrate by using sol-gel dip coating system. The effects of dopant concentration on the structure, morphology, and optical properties of Na-doped ZnO thin films deposited on glass substrate are investigated. Characterization of Zn1-xNaxO nanoparticles and thin films are examined using differential thermal analysis (DTA)/thermogravimetric analysis (TGA), Scanning electron microscope (SEM) and X-Ray diffractometer (XRD). Optical properties of Zn1-xNaxO thin films were obtained by using PG Instruments UV-Vis-NIR spectrophotometer in 190-1100 nm range. The structure, morphology, and optical properties of thin films are presented.

Growth and laser properties of Nd:Ca 4YO(BO 3) 3 crystal

NASA Astrophysics Data System (ADS)

Zhang, H. J.; Meng, X. L.; Zhu, L.; Wang, C. Q.; Cheng, R. P.; Yu, W. T.; Zhang, S. J.; Sun, L. K.; Chow, Y. T.; Zhang, W. L.; Wang, H.; Wong, K. S.

1999-02-01

Nd:Ca 4YO(BO 3) 3 (Nd:YCOB) crystal was grown by the Czochralski method, and its structure was measured by using a four circle X-ray diffractometer. The transparent spectrum from 200 to 2600 nm was measured at room temperature. The fluorescence spectrum near 1.06 μm showed that the main emission wavelength of Nd:YCOB crystal was centered at 1060.8 nm. Laser output at 1.06 μm has been demonstrated when it was pumped by a Ti:sapphire laser at the wavelength of 794 nm, the highest output power was 68 mW under pumping power of 311 mW, the pumping threshold was 163 mW and slope efficiency was 46.9%. The self-frequency doubled green light has been observed when it was pumped by a Ti:sapphire or a laser diode (LD). A 14.5 mm Nd:YCOB crystal sample cut at ( θ, φ)=(90°, 33°) was used for type I second-frequency generation (SHG) of the 1.06 μm laser pulse. The SHG conversion efficiency was 22%.

Effect of thermal annealing on structural and optical properties of In{sub 2}S{sub 3} thin films

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

Choudhary, Sonu, E-mail: sonuchoudhary1983@gmail.com

2015-08-28

There is a highly need of an alternate of toxic materials CdS for solar cell applications and indium sulfide is found the most suitable candidate to replace CdS due to its non-toxic and environmental friendly nature. In this paper, the effect of thermal annealing on the structural and optical properties of indium sulfide (In{sub 2}S{sub 3}) thin films is undertaken. The indium sulfide thin films of 121 nm were deposited on glass substrates employing thermal evaporation method. The films were subjected to the X-ray diffractometer and UV-Vis spectrophotometer respectively for structural and optical analysis. The XRD pattern show that themore » as-deposited thin film was amorphous in nature and crystallinity is found to be varied with annealing temperature. The optical analysis reveals that the optical band gap is varied with annealing. The optical parameters like absorption coefficient, extinction coefficient and refractive index were calculated. The results are in good agreement with available literature.« less

Electroplated L1{sub 0} CoPt thick-film permanent magnets

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

Oniku, Ololade D., E-mail: ololadeoniku@ufl.edu; Qi, Bin; Arnold, David P.

2014-05-07

The fabrication and magnetic characterization of 15-μm-thick electroplated L1{sub 0} CoPt hard magnets with good magnetic properties is reported in this paper. Experimental study of the dependence of the magnets' properties on annealing temperature reveals that an intrinsic coercivity H{sub ci} = ∼800 kA/m (10 kOe), squareness >0.8, and energy product of >150 kJ/m{sup 3} are obtained for photolithographically patterned structures (250 μm × 2 mm stripes; 15 μm thickness) electroplated on silicon substrates and annealed in hydrogen forming gas at 700 °C. Scanning electron microscopy is used to inspect the morphology of both the as-deposited and annealed magnetic layers, and X-ray Diffractometer analysis on the magnets annealed at 700 °Cmore » confirm a phase transformation to an ordered L1{sub 0} CoPt structure, with a minor phase of hcp Co. These thick films are intended for microsystems/MEMS applications.« less

Study of DDT and its derivatives DDD, DDE adsorption and degradation over Fe-SBA-15 at low temperature.

PubMed

Wang, Hailin; Tian, Hua; Hao, Zhengping

2012-01-01

Mesoporous SBA-15 with different Fe2O3 loading were synthesized by an in-situ coating progress for removals of dichlorodiphenyltrichloroethane (DDT) and its derivatives, i.e., 1,1-dichloro-2,2-bis-(p-chlorophenyl)ethane (DDD) and 1,1-dichloro-2,2-bis-(4-chloro -phenyl) ethane (DDE). The results from XRD (X-ray diffractometer), TEM (transmission electron microscopy) indicated that the iron could be well dispersed on SBA-15 within 6 wt.% Fe2O3 loading. Nitrogen adsorption-desorption tests indicated that the synthesized materials were characterized by ordered meso-structure, high surface area and large pore volume. DDTs were removed from aqueous media in 12-hr treatment and high removal efficiency of DDTs was achieved at over 94%. DDTs could be completely degraded at 350 degrees C under the existence of SBA-15 with 4 wt.% Fe2O3 loading. The final degradation products of DDT were dichlorobenzophenone (DCB) and bis-(4-chloro-phenyl) methane (DDM), suggesting a complete dechlorination from trichloromethyl.

First observation of magnetoelectric effect in M-type hexaferrite thin films

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

Mohebbi, Marjan; Ebnabbasi, Khabat; Vittoria, Carmine

2013-05-07

The magnetoelectric (ME) effect in M-type hexaferrite thin films is reported. Prior to this work, the ME effect in hexaferrite materials was observed only in bulk polycrystalline materials. Thin films of SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19} were grown on sapphire (0001) using pulsed laser deposition. The thin films were characterized by X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy, vibrating sample magnetometer, and ferromagnetic resonance. We measured saturation magnetization of 1250 G, g-factor of 2.66, and coercive field of 20 Oe for these magnetoelectric M-type hexaferrite thin films. The magnetoelectric effect was confirmed by monitoring the change rate in remanence magnetizationmore » with the application of DC voltage at room temperature and it gave rise to changes in remanence in the order of 12.8% with the application of only 1 V (DC voltage). We deduced a magnetoelectric coupling, {alpha}, of 6.07 Multiplication-Sign 10{sup -9} s m{sup -1} in SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19} thin films.« less

Plasma-induced damage of tungsten coatings on graphite limiters

NASA Astrophysics Data System (ADS)

Fortuna, E.; Rubel, M. J.; Psoda, M.; Andrzejczuk, M.; Kurzydowski, K. J.; Miskiewicz, M.; Philipps, V.; Pospieszczyk, A.; Sergienko, G.; Spychalski, M.; Zielinski, W.

2007-03-01

Vaccum plasma sprayed tungsten coatings with an evaporated sandwich Re-W interlayer on graphite limiter blocks were studied after the experimental campaign in the TEXTOR tokamak. The coating morphology was modified by high-heat loads and co-deposition of species from the plasma. Co-deposits contained fuel species, carbon, boron and silicon. X-ray diffractometer phase analysis indicated the coexistence of metallic tungsten and its carbides (WC and W2C) and boride (W2B). In the Re-W layer the presence of carbon was detected in a several micrometres thick zone. In the overheated part of the limiter, the Re-W layer was transformed into a sigma phase.

Effect of mechanical alloying synthesis process on the dielectric properties of (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} piezoceramics

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

Ghazanfari, Mohammad Reza, E-mail: Ghazanfari.mr@gmail.com; Amini, Rasool; Shams, Seyyedeh Fatemeh

Highlights: • MA samples show higher dielectric permittivity and Curie temperature. • In MA samples, dielectric loss is almost 27% less than conventional ones. • In MA samples, sintering time and temperature are lower than conventional ones. • In MA samples, particle morphology is more homogeneous conventional ones. • In MA samples, crystallite size is smaller conventional ones. - Abstract: In present work, in order to study the effects of synthesis techniques on dielectric properties, the BNBT lead-free piezoceramics with (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} stoichiometry (called as BNBT6) were synthesized by mechanical alloying (MA) and conventional mixed oxidesmore » methods. The structural, microstructural, and dielectric properties were carried out by X-ray diffractometer (XRD), scanning electron microscope (SEM), and impedance analyzer LCR meter, respectively. Based on results, the density of MA samples is considerably higher than conventional samples owning to smaller particles size and more uniformity of particle shape of MA samples. Moreover, the dielectric properties of MA samples are comparatively improved in which the dielectric loss of these samples is almost 27% less than conventional ones. Furthermore, MA samples exhibit obviously higher dielectric permittivity and Curie temperature compared to the conventional samples.« less

Unusual effect of water vapor pressure on dehydration of dibasic calcium phosphate dihydrate.

PubMed

Kaushal, Aditya M; Vangala, Venu R; Suryanarayanan, Raj

2011-04-01

Dibasic calcium phosphate occurs as an anhydrate (DCPA; CaHPO₄) and as a dihydrate (DCPD; CaHPO₄•2H₂O). Our objective was to investigate the unusual behavior of these phases. Dibasic calcium phosphate dihydrate was dehydrated in a (i) differential scanning calorimeter (DSC) in different pan configurations; (ii) variable-temperature X-ray diffractometer (XRD) at atmospheric and under reduced pressure, and in sealed capillaries; and (iii) water vapor sorption analyzer at varying temperature and humidity conditions. Dehydration was complete by 210°C in an open DSC pan and under atmospheric pressure in the XRD. Unlike "conventional" hydrates, the dehydration of DCPD was facilitated in the presence of water vapor. Variable-temperature XRD in a sealed capillary and DSC in a hermetic pan with pinhole caused complete dehydration by 100°C and 140°C, respectively. Under reduced pressure, conversion to the anhydrate was incomplete even at 300°C. The increase in dehydration rate with increase in water vapor pressure has been explained by the Smith-Topley effect. Under "dry" conditions, a coating of poorly crystalline product is believed to form on the surface of particles and act as a barrier to further dehydration. However, in the presence of water vapor, recrystallization occurs, creating cracks and channels and facilitating continued dehydration. Copyright © 2010 Wiley-Liss, Inc.

Effects of annealing on the structure and magnetic properties of Fe80B20 magnetostrictive fibers.

PubMed

Zhu, Qianke; Zhang, Shuling; Geng, Guihong; Li, Qiushu; Zhang, Kewei; Zhang, Lin

2016-07-04

Fe80B20 amorphous alloys exhibit excellent soft magnetic properties, high abrasive resistance and outstanding corrosion resistance. In this work, Fe80B20 amorphous micro-fibers with HC of 3.33 Oe were firstly fabricated and the effects of annealing temperature on the structure and magnetic properties of the fibers were investigated. In this study, Fe80B20 amorphous fibers were prepared by the single roller melt-spinning method. The structures of as-spun and annealed fibers were investigated by X-ray diffractometer (XRD) (PANalytical X,Pert Power) using Cu Kα radiation. The morphology of the fibers was observed by scanning electron microscopy (SEM) (HITACHI-S4800). Differential scanning calorimetry (DSC) measurements of the fibers were performed on Mettler Toledo TGA/DSC1 device under N2 protection. Vibrating sample magnetometer (VSM, Versalab) was used to examine the magnetic properties of the fibers. The resonance behavior of the fibers was characterized by an impedance analyzer (Agilent 4294A) with a home-made copper coil. The X-ray diffusion (XRD) patterns show that the fibers remain amorphous structure until the annealing temperature reaches 500°C. The differential scanning calorimetry (DSC) results show that the crystallization temperature of the fibers is 449°C. The crystallization activation energy is calculated to be 221 kJ/mol using Kissinger formula. The scanning electron microscopy (SEM) images show that a few dendrites appear at the fiber surface after annealing. The result indicates that the coercivity HC (//) and HC (⊥) slightly increases with increasing annealing temperature until 400°C, and then dramatically increases with further increasing annealing temperature which is due to significant increase in magneto-crystalline anisotropy and magneto-elastic anisotropy. The Q value firstly increases slightly when the annealing temperature rises from room temperature (RT) to 300°C, then decreases until 400°C. Eventually, the value of Q increases to ~2000 at annealing temperature of 500°C. In this study, Fe80B20 amorphous fibers with the diameter of 60 μm were prepared by the single roller melt-spinning method and annealed at 200°C, 300°C, 400°C, and 500°C, respectively. XRD results indicate that the fiber structure remains amorphous when the annealing temperature is below 400°C. α-Fe phase and Fe3B phase appear when the annealing temperature rises to 500°C, which is above the crystallization temperature of 449°C. The recrystallization activation energy is calculated to be 221 kJ/mol. The coercivity increases with increasing annealing temperature, which attributes to the increase of total anisotropy. All the as-spun and annealed fibers exhibit good resonance behavior for magnetostrictive sensors.

On the X-ray temperature of hot gas in diffuse nebulae

NASA Astrophysics Data System (ADS)

Toalá, J. A.; Arthur, S. J.

2018-05-01

X-ray emitting diffuse nebulae around hot stars are observed to have soft-band temperatures in the narrow range [1-3]× 106 K, independent of the stellar wind parameters and the evolutionary stage of the central star. We discuss the origin of this X-ray temperature for planetary nebulae (PNe), Wolf-Rayet nebulae (WR) and interstellar wind bubbles around hot young stars in our Galaxy and the Magellanic Clouds. We calculate the differential emission measure (DEM) distributions as a function of temperature from previously published simulations and combine these with the X-ray emission coefficient for the 0.3-2.0 keV band to estimate the X-ray temperatures. We find that all simulated nebulae have DEM distributions with steep negative slopes, which is due to turbulent mixing at the interface between the hot shocked stellar wind and the warm photoionized gas. Sharply peaked emission coefficients act as temperature filters and emphasize the contribution of gas with temperatures close to the peak position, which coincides with the observed X-ray temperatures for the chemical abundance sets we consider. Higher metallicity nebulae have lower temperature and higher luminosity X-ray emission. We show that the second temperature component found from spectral fitting to X-ray observations of WR nebulae is due to a significant contribution from the hot shocked stellar wind, while the lower temperature principal component is dominated by nebular gas. We suggest that turbulent mixing layers are the origin of the soft X-ray emission in the majority of diffuse nebulae.

On the X-ray temperature of hot gas in diffuse nebulae

NASA Astrophysics Data System (ADS)

Toalá, J. A.; Arthur, S. J.

2018-07-01

X-ray-emitting diffuse nebulae around hot stars are observed to have soft-band temperatures in the narrow range [1-3] × 106K, independent of the stellar wind parameters and the evolutionary stage of the central star. We discuss the origin of this X-ray temperature for planetary nebulae, Wolf-Rayet (WR) nebulae, and interstellar wind bubbles around hot young stars in our Galaxy and the Magellanic Clouds. We calculate the differential emission measure (DEM) distributions as a function of temperature from previously published simulations and combine these with the X-ray emission coefficient for the 0.3-2.0 keV band to estimate the X-ray temperatures. We find that all simulated nebulae have DEM distributions with steep negative slopes, which is due to turbulent mixing at the interface between the hot shocked stellar wind and the warm photoionized gas. Sharply peaked emission coefficients act as temperature filters and emphasize the contribution of gas with temperatures close to the peak position, which coincides with the observed X-ray temperatures for the chemical abundance sets we consider. Higher metallicity nebulae have lower temperature and higher luminosity X-ray emission. We show that the second temperature component found from spectral fitting to X-ray observations of WR nebulae is due to a significant contribution from the hot shocked stellar wind, while the lower temperature principal component is dominated by nebular gas. We suggest that turbulent mixing layers are the origin of the soft X-ray emission in the majority of diffuse nebulae.

Optical and structural properties of cadmium telluride films grown by glancing angle deposition

NASA Astrophysics Data System (ADS)

Ehsani, M. H.; Rezagholipour Dizaji, H.; Azizi, S.; Ghavami Mirmahalle, S. F.; Siyanaki, F. Hosseini

2013-08-01

Cadmium telluride films were grown by the glancing angle deposition (GLAD) technique. The samples were prepared under different incident deposition flux angles (α = 0°, 20° and 70° measured from the normal to the substrate surface). During deposition, the substrate temperature was maintained at room temperature. The structural study was performed using an x-ray diffraction diffractometer. The samples were found to be poly-crystalline with cubic structure for those deposited at α = 0° and 20° and hexagonal structure for the one deposited at 70°. The images of samples obtained by the field emission scanning electron microscopy technique showed that the GLAD method could produce a columnar layer tilted toward the incident deposition flux. The optical properties study by the UV-Vis spectroscopy technique showed that the use of this growth technique affected the optical properties of the films. A higher absorption coefficient in the visible and near-IR spectral range was observed for the sample deposited at α = 70°. This is an important result from the photovoltaic applications point of view where absorber materials with large absorption coefficients are needed. Also, it seems that the sample with a high incident deposition flux angle has the capability of making an n-CdTe/p-CdTe homo-junction.

Effect of zirconia nanoparticles on the rheological properties of silica-based shear thickening fluid

NASA Astrophysics Data System (ADS)

Sun, Li; Zhu, Jie; Wei, Minghai; Zhang, Chunwei; Song, Yansheng; Qi, Peipei

2018-05-01

In this study, the rheological characteristic of shear thickening fluid (STF) with various mass ratios of zirconium dioxide (ZrO2) to silicon dioxide (SiO2) was investigated. The influence of the ZrO2 mass ratio on the sensitivity of nano-ZrO2/SiO2-STF to temperature was further discussed. Nano-ZrO2/SiO2-STF of different concentrations (9.0–20.0 wt%) were prepared via an ultrasonication and mechanical stirring technique. The presence of ZrO2 and their interaction with the SiO2 nanoparticles in the STF were analyzed using scanning electron microscope (SEM), Energy dispersive spectroscopy (EDS) and x-ray diffractometer (XRD). The rheological testing results showed that the ZrO2/SiO2-STF system produced a considerable shear thickening effect; when the nano-ZrO2 mass ratio was 12%, the critical shear rate of the system was relatively small and the peak value of apparent viscosity was relatively large. More importantly, as the nano-ZrO2 mass ratio increased, temperature exerted less influence on the viscosity of the ZrO2/SiO2-STF system diminished, but still had a significant influence on the shear thickening effect.

Preparation of coenzyme Q10 liposomes using supercritical anti-solvent technique.

PubMed

Xia, Fei; Jin, Heyang; Zhao, Yaping; Guo, Xinqiu

2012-01-01

Coenzyme Q(10) (CoQ(10)) proliposomes were prepared using the supercritical anti-solvent (SAS) technique to encapsulate CoQ(10). The mixture of cholesterol and soya bean phosphatidylcholine (PC) was chosen as wall materials. The effects of operation conditions (temperature, pressure and components) on the recovery of CoQ(10) and the CoQ(10) loading in CoQ(10) proliposomes were studied. At the optimum conditions of pressure of 8.0 MPa, temperature of 35°C, the weight ratio of 1/10 between CoQ(10) and PC, and the weight ratio of 1/3 between cholesterol and PC, the CoQ(10) loading reached 8.92%. CoQ(10) liposomes were obtained by hydrating CoQ(10) proliposomes and the entrapment efficiency of CoQ(10) reached 82.28%. The morphologies of CoQ(10) proliposomes were characterized by scanning electron microscope, and their solid states were characterized by X-ray diffractometer. The structures of CoQ(10) liposomes were characterized by transmission electron microscope. The particle size distribution of CoQ(10) liposomes was determined by dynamic light scattering instrument. The results indicate that CoQ(10) liposomes with particle sizes about 50 nm can be easily obtained from hydrating CoQ(10) proliposomes prepared by SAS technique.

Crystal Structure and Magnetic Properties of New Cubic Quaternary Compounds RT2Sn2Zn18 (R = La, Ce, Pr, and Nd, and T = Co and Fe)

NASA Astrophysics Data System (ADS)

Isikawa, Yosikazu; Mizushima, Toshio; Ejiri, Jun-ichi; Kitayama, Shiori; Kumagai, Keigou; Kuwai, Tomohiko; Bordet, Pierre; Lejay, Pascal

2015-07-01

The new cubic quaternary intermetallic compounds RT2Sn2Zn18 (R = La, Ce, Pr, and Nd, and T = Co and Fe) were synthesized by the mixture-metal flux method using Zn and Sn. The crystal structure was investigated by powder X-ray diffraction and with a four-circle X-ray diffractometer using single crystals. The space group of the compounds is Fdbar{3}m (No. 227). The rare-earth atom is at the cubic site which is the center of a cage composed of Zn and Sn atoms. The crystal structure is the same as the CeCr2Al20-type crystal structure except the atoms at the 16c site, i.e., the Zn atoms at the 16c site are completely replaced by Sn atoms, indicating that the compounds are crystallographically new ordered quaternary compounds. The lattice parameter a and the physical properties of the magnetic susceptibility χ, the magnetization M, and the specific heat C of these cubic caged compounds were investigated. LaCo2Sn2Zn18 and LaFe2Sn2Zn18 are enhanced Pauli paramagnets that originate from the Co and Fe itinerant 3d electrons. CeCo2Sn2Zn18 and CeFe2Sn2Zn18 are also enhanced Pauli paramagnets that originate from both the 3d electrons and Ce 4f electrons. PrCo2Sn2Zn18 and PrFe2Sn2Zn18 are nonmagnetic materials with huge values of C divided by temperature, which indicates that the ground state of Pr ions is a non-Kramers' doublet. NdCo2Sn2Zn18 and NdFe2Sn2Zn18 are magnetic materials with the Néel temperatures of 1.0 and 3.8 K, respectively. All eight compounds have large magnetic moments of Co/Fe in the paramagnetic temperature region, and thus their magnetic moments are inferred to be magnetically frustrating owing to the pyrochlore lattice in the low-temperature region.

Low-angle X-ray scattering properties of irradiated spices

NASA Astrophysics Data System (ADS)

Almeida, A. P. G.; Braz, D.; Barroso, R. C.; Lopes, R. T.

2007-09-01

The scattering of X-rays at low angles (LAXS) is a technique dominated by the coherent scattering process. One characteristic observation of low-angle coherent scattering is the so-called molecular interference effect, being characterized by the presence of one or more peaks in the forward direction of scattering. In the present study, LAXS profiles from five different spices are carefully measured in order to establish characteristic scattering signatures. Samples of Ceylon cinnamon, cumin, nutmeg, paprika and black pepper were bought in local market in Rio de Janeiro, Brazil. The LAXS patterns were obtained using a Shimadzu DRX 6000 diffractometer in reflection geometry. Coherent scattering patterns are measured for the samples for θ=5-35°. The data were collected in 0.05° increments every 3 s. In order to evaluate the possible molecular structure changes caused to the irradiation procedure, the signatures obtained for control (non-irradiated) spices were compared with spice samples irradiated with different doses varying from 3 to 40 kGy. The LAXS patterns of all samples were obtained after 30, 60, 90, 120 days to evaluate the effect of storage period. Scattering profiles from spices irradiated with different irradiation doses were obtained and the results compared. For each spice, there is no considerable deviation in shape in function of the irradiation dose. It indicates that the molecular structure of each analyzed spices is preserved considering the dose range chosen. The results show that the molecular structure was found to be stable during storage at the ambient temperature for up to 4 months.

Structure and absolute configuration of some 5-chloro-2-methoxy-N-phenylbenzamide derivatives

NASA Astrophysics Data System (ADS)

Galal, Alaaeldin M. F.; Shalaby, Elsayed M.; Abouelsayed, Ahmed; Ibrahim, Medhat A.; Al-Ashkar, Emad; Hanna, Atef G.

2018-01-01

The absolute configuration of 5-chloro-2-methoxy-N-phenylbenzamide single crystal [compound (1)] and the effect of introducing -[CH2]n-, n = 1,2 group adjacent to the amide group [compounds (2) and (3)], were studied. Furthermore, the replacement of the methoxy group with a hydroxy group [compound (4)] was defined. Proton and carbon-13 NMR spectrometer were used to record the structural information of the prepared compounds. X-ray single crystal diffractometer were used to elucidate the 3D structural configurations. Intensity data for the studied compounds were collected at room temperature. The X-ray data prove that compound (1) is almost planar, with maximum r.m.s. deviations of 0.210(3) Å corresponds to C13. This planarity starts to disturb by adding -[CH2]n-, n = 1,2 groups between the NH group and the phenyl ring in compounds (2) and (3), respectively. By replacing the OCH3 group by an OH group in compound (4), the plane of the chlorophenyl moiety is nearly perpendicular to that of the phenyl ring. Such new structural configurations were further illustrated by the infrared, and ultraviolet-visible spectroscopy measurements in the frequency range 400-4000 cm-1 and 190-1100 nm, respectively. Spectroscopic analyses were verified with the help of molecular modeling using density functional theory. The estimated total dipole moment for the prepared compounds reflects its ability to interact with its surrounding molecules. The higher dipole moment for a given structures is combined with the higher reactivity for potential use in medicinal applications.

Influence of Austempering Heat Treatment on Microstructure and Mechanical Properties of Medium Carbon High Silicon Steel

NASA Astrophysics Data System (ADS)

Palaksha, P. A.; Ravishankar, K. S.

2017-08-01

In the present investigation, the influence of austempering heat treatment on the microstructure and mechanical properties of medium carbon high silicon steel was evaluated. The test specimens were machined from the as-received steel and were first austenitised at 900 °C for 45 minutes, followed by austempering heat treatment in salt bath at various temperatures 300 °C, 350 °C and 400 °C for a fixed duration of two hours, after that those specimens were air-cooled to room temperature. The characterization studies were carried out using optical microscope, scanning electron microscope (SEM) and x-ray diffractometer (XRD) and then correlated to the hardness and tensile properties. Results indicate that, the specimens austempered at lower temperature i.e. at 300 °C, which offered high hardness, tensile strength and lower ductility (1857 MPa and 13.3 %) due to the presence of acicular bainite i.e. lower bainite and also some martensite in the microstructure. At 350 °C, reduction in the tensile strength and hardness was observed, but comparatively higher ductility, which was favored by the presence of bainite laths i.e. upper bainitic structure along with higher retained austenite content. Finally at 400 °C, reduction in both ductility and tensile strength was observed, which is due to the precipitation of carbides between the banite laths, however good strain hardening response was observed at austempering temperatures of 350 °C and 400 °C.

NH3-SCR denitration catalyst performance over vanadium-titanium with the addition of Ce and Sb.

PubMed

Xu, Chi; Liu, Jian; Zhao, Zhen; Yu, Fei; Cheng, Kai; Wei, Yuechang; Duan, Aijun; Jiang, Guiyuan

2015-05-01

Selective catalytic reduction technology using NH3 as a reducing agent (NH3-SCR) is an effective control method to remove nitrogen oxides. TiO2-supported vanadium oxide catalysts with different levels of Ce and Sb modification were prepared by an impregnation method and were characterized by X-ray diffractometer (XRD), Brunauer-Emmett-Teller (BET), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Raman and Hydrogen temperature-programmed reduction (H2-TPR). The catalytic activities of V5CexSby/TiO2 catalysts for denitration were investigated in a fixed bed flow microreactor. The results showed that cerium, vanadium and antimony oxide as the active components were well dispersed on TiO2, and the catalysts exhibited a large number of d-d electronic transitions, which were helpful to strengthen SCR reactivity. The V5CexSby/TiO2 catalysts exhibited a good low temperature NH3-SCR catalytic activity. In the temperature range of 210 to 400°C, the V5CexSby/TiO2 catalysts gave NO conversion rates above 90%. For the best V5Ce35Sb2/TiO2 catalyst, at a reaction temperature of 210°C, the NO conversion rate had already reached 90%. The catalysts had different catalytic activity with different Ce loadings. With the increase of Ce loading, the NO conversion rate also increased. Copyright © 2015. Published by Elsevier B.V.

Additional of polyethylene glycol on the preparation of LaPO4:Eu3+ phosphor

NASA Astrophysics Data System (ADS)

Panatarani, Camellia; Joni, I. Made

2013-09-01

Solution phase method was used to synthesis nanocrystal LaPO4:Eu3+. Polyethylene glycol with vary molecular weight (MW) was added to allow an exothermic reaction to get a high crystalinity of LaPO4:Eu3+. The x-ray pattern of as prepared LaPO4 was obtained by using an X'pert PANalytical diffractometer with CuKα radiation (λ = 1.5406 Å) and the photoluminescent measurement spectra is obtained by using Fluorescence Spectrometer LS55, Perkin Elmer. The additional of various MW of polyethylene glycol into the precursor solution of LaPO4:Eu3+ affected the crystal structure and luminescent properties. Higher MW of PEG depressing the luminescent spectra. The emission origin from 5D0-7F4 transition vanished by additional 500,000 and 2,000,000 MW of PEG.

Scanning electron microscopy, X-ray diffraction and thermal analysis study of the TiH{sub 2} foaming agent

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

Mandrino, Djordje, E-mail: djordje.mandrino@imt.si; Paulin, Irena; Skapin, Sreco D.

2012-10-15

The decomposition of commercially available TiH{sub 2} was investigated while performing different thermal treatments. TiH{sub 2} powder, which is widely used as a foaming agent, was heat treated at 450 Degree-Sign C for various times, from 15 min to 120 min. Scanning electron microscopy (SEM) images of the surfaces at different magnifications were obtained and interpreted. A Bragg-Brentano X-ray diffractometer was used to measure the X-ray diffraction (XRD) spectra on all five samples. A close examination of the diffraction spectra showed that for an as-received sample and samples undergoing the longest thermal treatment (1 and 2 h) these spectra canmore » be explained as deriving from cubic TiH{sub 1.924}, while for the other two samples they can be explained as deriving from tetragonal TiH{sub 1.924}. A constant-unit-cell-volume phase transition between the cubic and tetragonal phases in TiH{sub 2-y}-type compounds had been described in the literature. The unit-cell parameters obtained from measured spectra confirm that within the measurement uncertainty the unit-cell volume is indeed constant in all five samples. Thermo-gravimetry (TG) and differential thermal analysis (DTA) measurements were performed on all the samples, showing that the intensity of the dehydrogenation depends on the previous treatment of the TiH{sub 2}. After the thermal analysis XRD of the samples was performed again and the material was found to exhibit a Ti-like unit cell, but slightly enlarged due to the unreleased hydrogen. - Highlights: Black-Right-Pointing-Pointer TiH{sub 2} samples were cubic or tetragonal TiH{sub 1.924} Black-Right-Pointing-Pointer Onset of the hydrogen release temperature increases with the pre-treatment time. Black-Right-Pointing-Pointer Thermal dehydrogenation for the as-prepared TiH{sub 2} is a three-step process. Black-Right-Pointing-Pointer After thermal analysis 2 residual hydrogen TiH{sub x} phases, close to {alpha}Ti, appeared.« less

Doping effect on SILAR synthesized crystalline nanostructured Cu-doped ZnO thin films grown on indium tin oxide (ITO) coated glass substrates and its characterization

NASA Astrophysics Data System (ADS)

Dhaygude, H. D.; Shinde, S. K.; Velhal, Ninad B.; Takale, M. V.; Fulari, V. J.

2016-08-01

In the present study, a novel chemical route is used to synthesize the undoped and Cu-doped ZnO thin films in aqueous solution by successive ionic layer adsorption and reaction (SILAR) method. The synthesized thin films are characterized by x-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray analysis (EDAX), contact angle goniometer and UV-Vis spectroscopic techniques. XRD study shows that the prepared films are polycrystalline in nature with hexagonal crystal structure. The change in morphology for different doping is observed in the studies of FE-SEM. EDAX spectrum shows that the thin films consist of zinc, copper and oxygen elements. Contact angle goniometer is used to measure the contact angle between a liquid and a solid interface and after detection, the nature of the films is initiated from hydrophobic to hydrophilic. The optical band gap energy for direct allowed transition ranging between 1.60-2.91 eV is observed.

Facile Synthesis and Characterization of ZrO₂ Nanoparticles via Modified Co-Precipitation Method.

PubMed

Ramachandran, M; Subadevi, R; Liu, Wei-Ren; Sivakumar, M

2018-01-01

The crystalline Zirconium oxide (ZrO2) nano particles were synthesized using optimized content of Zirconium nitrate (Zr(NO3)2·3H2O) with varying KOH concentration (0.5, 1 and 1.5 M) by co-precipitation method. The thermal history of the precursor was carefully analyzed through Thermogravimetric (TG/DTA) measurement. The as prepared samples were characterized to ensure structural, functional, morphological, compositional, chemical composition and band gap by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Laser Raman, scanning electron microscopy (SEM), High resolution Transverse Electron Microscopy (HR-TEM), X-ray photo electron spectroscopy (XPS), EDX, Photo luminescence spectroscopy (PL). The monoclinic structure with space group P21/c has been confirmed from XRD (JCPDS 89-9066). The Zr-O stretching vibration and Zr-O2-Zr bending vibrations were confirmed through FTIR analysis. The well dispersed particles with spherical morphology were confirmed through SEM and TEM analysis. The oxidation states of Zr, O and C were confirmed through XPS analysis. The oxygen vacancies and band gap of the particles were investigated through PL analysis.

Phase state of a Bi-43 wt % Sn superplastic alloy and its changes under the effect of external mechanical stresses and aging

NASA Astrophysics Data System (ADS)

Korshak, V. F.; Chushkina, R. A.; Shapovalov, Yu. A.; Mateichenko, P. V.

2011-07-01

Samples of a Bi-43 wt % Sn superplastic alloy have been studied by X-ray diffraction in the ascast state, after compression of as-cast samples to ˜70% on a hydraulic press, after aging in the as-cast and preliminarily compressed state, and using samples deformed under superplastic conditions. The X-ray diffraction studies have been carried out using a DRON-2.0 diffractometer in Cu Kα radiation. The samples aged and deformed under superplasticity conditions have been studied using electron-microprobe analysis in a JSM-820 scanning electron microscope equipped with a LINK AN/85S EDX system. It has been found that the initial structural-phase state of the alloy was amorphous-crystalline. Causes that lead to a change in this state upon deformation and aging are discussed. A conclusion is made that the superplasticity effect manifests itself against the background of processes that are stipulated by the tendency of the initially metastable alloy to phase equilibrium similarly to what is observed in the Sn-38 wt % Pb eutectic alloy studied earlier.

A new x-ray interface and surface scattering environmental cell design for in situ studies of radioactive and atmosphere-sensitive samples.

PubMed

Schmidt, M; Eng, P J; Stubbs, J E; Fenter, P; Soderholm, L

2011-07-01

We present a novel design of a purpose-built, portable sample cell for in situ x-ray scattering experiments of radioactive or atmosphere sensitive samples. The cell has a modular design that includes two independent layers of containment that are used simultaneously to isolate the sensitive samples. Both layers of containment can be flushed with an inert gas, thus serving a double purpose as containment of radiological material (either as a solid sample or as a liquid phase) and in separating reactive samples from the ambient atmosphere. A remote controlled solution flow system is integrated into the containment system that allows sorption experiments to be performed on the diffractometer. The cell's design is discussed in detail and we demonstrate the cell's performance by presenting first results of crystal truncation rod measurements. The results were obtained from muscovite mica single crystals reacted with 1 mM solutions of Th(IV) with 0.1 M NaCl background electrolyte. Data were obtained in specular as well as off-specular geometry.

Optical properties and crystallinity of silver mirrors under a 35 krad cobalt-60 radiation

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

Chiu, Po-Kai, E-mail: pkchiu@itrc.narl.org.tw; Chiang, Donyau; Lee, Chao-Te

2015-09-15

This study addresses the effects of thin film optical design and environmental radiation on the optical properties of silver mirrors. Different experimental thin film optical designs are selected, and the film stack is built using Macleod's approach. Mirror elements are exposed to the same dose of radiation and their properties are characterized using a spectrophotometer equipped with an integration sphere and an x-ray diffractometer. Spectrophotometric analyses of mirrors exposed to about 35 krad of {sup 60}Co radiations overall show that the B270 glass substrates coated with titanium oxide (TiO{sub 2}), silicon dioxide (SiO{sub 2}), pure chrome, and pure silver effectivelymore » reduces radiation damage. The absorption spectrum of the TiO{sub 2} film in the visible region decreases after radiation and displays drifting. As thin metal films comparison, the silver thin film exhibits higher radiation resistance than the chrome thin film. The x-ray diffraction analysis on metal film layers reveals that crystallinity slightly increases when the silver thin film is irradiated.« less

Extracting the pair distribution function of liquids and liquid-vapor surfaces by grazing incidence x-ray diffraction mode.

PubMed

Vaknin, David; Bu, Wei; Travesset, Alex

2008-07-28

We show that the structure factor S(q) of water can be obtained from x-ray synchrotron experiments at grazing angle of incidence (in reflection mode) by using a liquid surface diffractometer. The corrections used to obtain S(q) self-consistently are described. Applying these corrections to scans at different incident beam angles (above the critical angle) collapses the measured intensities into a single master curve, without fitting parameters, which within a scale factor yields S(q). Performing the measurements below the critical angle for total reflectivity yields the structure factor of the top most layers of the water/vapor interface. Our results indicate water restructuring at the vapor/water interface. We also introduce a new approach to extract g(r), the pair distribution function (PDF), by expressing the PDF as a linear sum of error functions whose parameters are refined by applying a nonlinear least square fit method. This approach enables a straightforward determination of the inherent uncertainties in the PDF. Implications of our results to previously measured and theoretical predictions of the PDF are also discussed.

Diagenesis in the Murray Formation, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Ming, D. W.; Morris, R. V.; Blake, D. F.; Bristow, T. F.; Chipera. S. J.; Vaniman, D. T.; Yen, A. S.; Grotzinger, J. P.; Downs, R. T.;

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding

PubMed Central

Liu, Yanhui; Qu, Weicheng; Su, Yu

2016-01-01

In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and energy dispersive X-ray spectroscopy (EDS) confirmed that the coating was composed of TiC particles and two kinds of α-Fe phase. The fine TiC particles were only a few microns in size and uniformly distributed on the matrix phase in the composite coating. The microstructure characteristic of the composite coating resulted in the microhardness rising to about 1000 HV0.3 (China GB/T 4342-1991) and the wear resistance significantly increased relative to the substrate. In addition, the fine and homogeneous solidification microstructure without graphite phase in the transition zone led to a good metallurgical bonding and transition between the coating and the substrate. It was of great significance for the cast iron to modify the surface and repair surface defects or surface damage. PMID:28773934

Investigations into the Anti-Felting Properties of Sputtered Wool Using Plasma Treatment

NASA Astrophysics Data System (ADS)

M. Borghei, S.; Shahidi, S.; Ghoranneviss, M.; Abdolahi, Z.

2013-01-01

In this research the effects of mordant and plasma sputtering treatments on the crystallinity and morphological properties of wool fabrics were investigated. The felting behavior of the treated samples was also studied. We used madder as a natural dye and copper sulfate as a metal mordant. We also used copper as the electrode material in a DC magnetron plasma sputtering device. The anti-felting properties of the wool samples before and after dying was studied, and it was shown that the shrink resistance and anti-felting behavior of the wool had been significantly improved by the plasma sputtering treatment. In addition, the percentage of crystallinity and the size of the crystals were investigated using an X-ray diffractometer, and a scanning electron microscope was used for morphological analysis. The amount of copper particles on the surface of the mordanted and sputtered fabrics was studied using the energy dispersive X-ray (EDX) method, and the hydrophobic properties of the samples were examined using the water drop test. The results show that with plasma sputtering treatment, the hydrophobic properties of the surface of wool become super hydrophobic.

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding.

PubMed

Liu, Yanhui; Qu, Weicheng; Su, Yu

2016-09-30

In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and energy dispersive X-ray spectroscopy (EDS) confirmed that the coating was composed of TiC particles and two kinds of α -Fe phase. The fine TiC particles were only a few microns in size and uniformly distributed on the matrix phase in the composite coating. The microstructure characteristic of the composite coating resulted in the microhardness rising to about 1000 HV0.3 (China GB/T 4342-1991) and the wear resistance significantly increased relative to the substrate. In addition, the fine and homogeneous solidification microstructure without graphite phase in the transition zone led to a good metallurgical bonding and transition between the coating and the substrate. It was of great significance for the cast iron to modify the surface and repair surface defects or surface damage.

Electrodeposition of Manganese-Nickel Oxide Films on a Graphite Sheet for Electrochemical Capacitor Applications.

PubMed

Lee, Hae-Min; Lee, Kangtaek; Kim, Chang-Koo

2014-01-09

Manganese-nickel (Mn-Ni) oxide films were electrodeposited on a graphite sheet in a bath consisting of manganese acetate and nickel chloride, and the structural, morphological, and electrochemical properties of these films were investigated. The electrodeposited Mn-Ni oxide films had porous structures covered with nanofibers. The X-ray diffractometer pattern revealed the presence of separate manganese oxide (g-MnO₂) and nickel oxide (NiO) in the films. The electrodeposited Mn-Ni oxide electrode exhibited a specific capacitance of 424 F/g in Na₂SO₄ electrolyte. This electrode maintained 86% of its initial specific capacitance over 2000 cycles of the charge-discharge operation, showing good cycling stability.

Structural and optical properties of ITO and Cu doped ITO thin films

NASA Astrophysics Data System (ADS)

Chakraborty, Deepannita; Kaleemulla, S.; Rao, N. Madhusudhana; Subbaravamma, K.; Rao, G. Venugopal

2018-04-01

(In0.95Sn0.05)2O3 and (In0.90Cu0.05Sn0.05)2O3 thin films were coated onto glass substrate by electron beam evaporation technique. The structural and optical properties of ITO and Cu doped ITO thin films have been studied by X-ray diffractometer (XRD) and UV-Vis-NIR spectrophotometer. The crystallite size obtained for ITO and Cu doped ITO thin films was in the range of 24 nm to 22 nm. The optical band gap of 4 eV for ITO thin film sample has been observed. The optical band gap decreases to 3.85 eV by doping Cu in ITO.

Electrochemical Deposition of Si-Ca/P on Nanotube Formed Beta Ti Alloy by Cyclic Voltammetry Method.

PubMed

Jeong, Yong-Hoon; Choe, Han-Cheol

2015-08-01

The purpose of this study was to investigate electrochemical deposition of Si-Ca/P on nanotube formed Ti-35Nb-10Zr alloy by cyclic voltammetry method. Electrochemical deposition of Si substituted Ca/P was performed by pulsing the applied potential on nanotube formed surface. The surface characteristics were observed by field-emission scanning electron microscopy, X-ray diffractometer, and potentiodynamic polarization test. The phase structure and surface morphologies of Si-Ca/P deposition were affected by deposition cycles. From the anodic polarization test, nanotube formed surface at 20 V showed the high corrosion resistance with lower value of Icorr, I300, and Ipass.

Non-platinum metal-organic framework based electro-catalyst for promoting oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Das, Dipanwita; Raut, Vrushali; Kireeti, Kota V. M. K.; Jha, Neetu

2018-04-01

We developed two non-precious Metal Organic Framework (MOF) based electrocatalysts, MOF-5 and MOF-i using solvothermal and refluxing methods. The MOFs prepared has been characterized by powder X-ray diffractometer (XRD), Fourier Transform Infra-Red Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) for structural and morphological insights. SEM images reveal cubic shape for solvothermally synthesized MOF-5, whereas refluxing method leads to platelet morphology of MOF-i. The synthesized MOFs has been investigated for Oxygen Reduction Reaction (ORR) studies using Cyclic Voltammetry (CV) and Linear Sweep Voltammetry (LSV), with MOF modified Glassy Carbon (GC) as working electrode. The electrochemical data suggests higher activity of MOF-5 towards ORR compared to MOF-i.

X-ray metal film filters at cryogenic temperatures

NASA Technical Reports Server (NTRS)

Keski-Kuha, Ritva A. M.

1989-01-01

Thin aluminum foil filters have been evaluated at cryogenic temperatures. The results of the test program, including cold cycling and vibration testing, indicate that these filters are fully successful at cryogenic temperatures and can provide the high X-ray transmittance and high background rejection required for the blocking filters which are being developed for the X-Ray Spectrometer, one of the focal plane instruments on the Advanced X-Ray Astrophysics Facility.

Structural studies of ZnO nanostructures by varying the deposition parameters

NASA Astrophysics Data System (ADS)

Yunus, S. H. A.; Sahdan, M. Z.; Ichimura, M.; Supee, A.; Rahim, S.

2017-01-01

The effect of Zinc Oxide (ZnO) thin film on the growth of ZnO nanorods (NRs) was investigated. The structures of ZnO NRs were synthesized by chemical bath deposition (CBD) method in aqueous solution of N2O6Zn.6H2O and C6H12N4 at 90°C of deposition temperature. One of the ZnO NRs samples was deposited on a ZnO seed layer coated on a glass substrate to investigate the properties of ZnO NRs without receiving effect of other materials. Next, for diode application, the ZnO NRs was deposited on tin monosulfide (SnS) coated on indium-tin-oxide (ITO) coated glass substrate (SnS/ITO). The next, the ZnO structural properties were studied from surface morphology, X-ray diffractometer (XRD) spectra, and chemical composition by using field emission scanning electron microscope (FESEM), XRD and energy dispersive X-ray Spectroscopy (EDX). The growth of ZnO NRs on ZnO seed layer was investigated by ZnO seed layer condition while the growth of ZnO NRs on SnS/ITO was investigated by deposition time and deposition temperature parameters. From FESEM images, aligned ZnO NRs were obtained, and the diameters of ZnO NRs were 0.024-3.94 µm. The SnS thin film was affected by the diameter of ZnO NRs which are the ZnO NRs grow on SnS thin films has a larger diameter compared to ZnO NRs grow on ZnO seed layer. Besides that, all of ZnO peaks observed from XRD corresponding to the wurzite structure and preferentially oriented along the c-axis. In addition, EDX shows a high composition of zinc (Zn) and oxygen (O) signals, which indicated that the NRs are indeed made up of Zn and O.

Band Offset Measurements in Atomic-Layer-Deposited Al2O3/Zn0.8Al0.2O Heterojunction Studied by X-ray Photoelectron Spectroscopy.

PubMed

Yan, Baojun; Liu, Shulin; Heng, Yuekun; Yang, Yuzhen; Yu, Yang; Wen, Kaile

2017-12-01

Pure aluminum oxide (Al 2 O 3 ) and zinc aluminum oxide (Zn x Al 1-x O) thin films were deposited by atomic layer deposition (ALD). The microstructure and optical band gaps (E g ) of the Zn x Al 1-x O (0.2 ≤ x ≤ 1) films were studied by X-ray diffractometer and Tauc method. The band offsets and alignment of atomic-layer-deposited Al 2 O 3 /Zn 0.8 Al 0.2 O heterojunction were investigated in detail using charge-corrected X-ray photoelectron spectroscopy. In this work, different methodologies were adopted to recover the actual position of the core levels in insulator materials which were easily affected by differential charging phenomena. Valence band offset (ΔE V ) and conduction band offset (ΔE C ) for the interface of the Al 2 O 3 /Zn 0.8 Al 0.2 O heterojunction have been constructed. An accurate value of ΔE V  = 0.82 ± 0.12 eV was obtained from various combinations of core levels of heterojunction with varied Al 2 O 3 thickness. Given the experimental E g of 6.8 eV for Al 2 O 3 and 5.29 eV for Zn 0.8 Al 0.2 O, a type-I heterojunction with a ΔE C of 0.69 ± 0.12 eV was found. The precise determination of the band alignment of Al 2 O 3 /Zn 0.8 Al 0.2 O heterojunction is of particular importance for gaining insight to the design of various electronic devices based on such heterointerface.

OSO-8 X-ray spectra of clusters of galaxies. 1. Observations of twenty clusters: Physical correlations

NASA Technical Reports Server (NTRS)

Mushotzky, R. F.; Serlemitsos, P. J.; Smith, B. W.; Boldt, E. A.; Holt, S. S.

1978-01-01

OSO-8 X-ray spectra from 2 to 20 keV were analyzed for 26 clusters of galaxies. Temperature, emission integrals, iron abundances, and low energy absorption measurements are given. Eight clusters have positive iron emission line detections at the 90% confidence level, and all twenty cluster spectra are consistent with Fe/H=0.000014 by number with the possible exception of Virgo. Physical correlations between X-ray spectral parameters and other cluster properties are examined. It is found that: (1) the X-ray temperature is approximately proportional to the square of the velocity dispersion of the galaxies; (2) the emission integral and therefore the bolometric X-ray luminosity is a strong function of the X-ray temperature; (3) the X-ray temperature and emission integral are better correlated with cluster central galaxy density than with richness; (4) temperature and emission integral are separately correlated with Rood-Sastry type; and (5) the fraction of galaxies which are spirals is correlated with the observed ram pressure in the cluster core.

Preparation, Structural and Dielectric Behaviors of CoxMn1-xMn2O4 (0 ≤ x ≤ 1) Nanoparticles

NASA Astrophysics Data System (ADS)

Taufiq, A.; Muzammil, M.; Fuad, A.; Hidayat, N.; Sunaryono, S.; Mufti, N.; Hidayat, A.; Diantoro, M.; Munasir, M.

2018-05-01

Cobalt-manganese oxide nanoparticles become remarkable metal oxides due to their physical characters, for example, their electrical properties. In this paper, we report the synthesis of Co x Mn1-x Mn2O4 (0 ≤ x ≤ 1) nanoparticles via a precipitation method. The structural and dielectric properties were investigated by means of X-ray diffractometer (XRD) and LCR-meter. From the data analysis, it was found that the Co x Mn1-x Mn2O4 particles structured spinel cubic with the particle size ranging from 22.7 to 28.6 nm. Increasing Co2+ ions led to declining lattice and crystal volume of the Co x Mn1-x Mn2O4 nanoparticles. Such phenomenon was originated from the substitution process of Co2+ ions that change the metal construction both at the octahedral and tetrahedral sites. Furthermore, the Co2+ ion substitution resulted in an increase in the dielectric properties of the Co x Mn1-x Mn2O4 nanoparticles regarding with dipole moment. Interestingly, the increase was also influenced by reducing the particle size and crystal volume of the Co x Mn1-x Mn2O4 nanoparticles.

Modifications developed to improve x-ray detection devices

NASA Technical Reports Server (NTRS)

1994-01-01

Improvements in the development of x-ray detection devices are described. Emphasis is placed on lowering the temperature in order to achieve better x-ray response. A simplified charge integrator schematic is presented along with supporting tables. By using cryogenic operating temperatures, these x-ray detectors may eventually surpass the performance of the best semiconductor detectors.

Effects of Cu and Ag as ternary and quaternary additions on some physical properties of SnSb7 bearing alloy

NASA Astrophysics Data System (ADS)

El-Bediwi, A. B.

2004-02-01

The structure, electrical resistivity, and elastic modulus of SnSb7 and SnSb7X (X = Cu , Ag, or Cu and Ag) rapidly solidified alloys have been investigated using X-ray diffractometer, double bridge, and dynamic resonance techniques. Copper and silver additions to SnSb result in the formation of a eutectic matrix containing embedded crystals (intermetallic phases) of SnCu, SnAg, and SnSb. The hard crystals SnCu, SnAg, and SnSb increase the overall hardness and wear resistance of SnSb bearing alloys. Addition of copper and silver improves internal friction, electrical conductivity, and elastic modulus values of SnSb rapidly solidified bearing alloys. The internal friction, elastic modulus, and electrical resistivity values are relatively sensitive to the composition of the intermediate phases in the matrix. The SbSb(7)Cu(2)g(2) has better properties (lowest internal friction, cost, adequate elastic modulus, and electrical resistivity) for bearing alloys as compared to cast iron and bronzes.

Seminar on "MAGNETISM"

NASA Astrophysics Data System (ADS)

Lander, Gerard H.

1998-12-01

During the course of this seminar we had 4 presentations by people who had participated in the earlier poster session. The speakers and titles were: (1) U. Gasser (PSI, Switzerland): "Dimer splitting in RxY1-xNi2B2C". High resolution inelastic work done on polycrystalline samples at the IRIS spectrometer at ISIS and determining the exchange interactions in these superconducting materials. (2) B. Roessli (PSI, Switzerland): "Enhancement of magnetic fluctuations in UPd2Al3 below Tc". High resolution work done on single crystals at the cold source IN14 triple axis spectrometer at the ILL and also involving polarisation analysis. (3) P. Wisniewski (Wroclaw, Poland): "Magnetic structures in U3X4-type uranium pnictides - neutron diffraction studies". Elastic scattering experiments done at Saclay on single crystals with both polarised and unpolarised neutrons. (4) A. Schneidewind (TU Dresden): "Investigation of magnetic structures of NdCu2 by synchrotron x-ray scattering". Work done at the ID20 diffractometer at the ESRF and involving resonant and non-resonant scattering, as well as polarisation analysis…

Effect of negative bias on TiAlSiN coating deposited on nitrided Zircaloy-4

NASA Astrophysics Data System (ADS)

Jun, Zhou; Zhendong, Feng; Xiangfang, Fan; Yanhong, Liu; Huanlin, Li

2018-01-01

TiAlSiN coatings were deposited on the nitrided Zircaloy-4 by multi-arc ion plating at -100 V, -200 V and -300 V. In this study, the high temperature oxidation behavior of coatings was tested by a box-type resistance furnace in air for 3 h at 800 °C; the macro-morphology of coatings was observed and analyzed by a zoom-stereo microscope; the micro-morphology of coatings was analyzed by a scanning electron microscopy (SEM), and the chemical elements of samples were analyzed by an energy dispersive spectroscopy(EDS); the adhesion strength of the coating to the substrate was measured by an automatic scratch tester; and the phases of coatings were analyzed by an X-ray diffractometer(XRD). Results show that the coating deposited at -100 V shows better high temperature oxidation resistance behavior, at the same time, Al elements contained in the coating is of the highest amount, meanwhile, the adhesion strength of the coating to the substrate is the highest, which is 33N. As the bias increases, high temperature oxidation resistance behavior of the coating weakens first and then increases, the amount of large particles on the surface of the coating increases first and then decreases whereas the density of the coating decreases first and then increases, and adhesion strength of the coating to the substrate increases first and then weakens. The coating's quality is relatively poor when the bias is -200 V.

Effect of cobalt doping on crystallinity, stability, magnetic and optical properties of magnetic iron oxide nano-particles

NASA Astrophysics Data System (ADS)

Anjum, Safia; Tufail, Rabia; Rashid, Khalid; Zia, Rehana; Riaz, S.

2017-06-01

This paper is dedicated to investigate the effect of Co2+ ions in magnetite Fe3O4 nano-particles with stoichiometric formula CoxFe3-xO4 where (x = 0, 0.05, 0.1 and 0.15) prepared by co-precipitation method. The structural, thermal, morphological, magnetic and optical properties of magnetite and Co2+ doped magnetite nanoparticles have been carried out using X-ray Diffractometer, Fourier Transform Infrared Spectroscopy, Themogravimetric Analysis, Scanning Electron Microscopy, Vibrating Sample Magnetometer (VSM) and UV-Vis Spectrometer (UV-Vis) respectively. Structural analysis verified the formation of single phase inverse spinel cubic structure with decrease in lattice parameters due to increase in cobalt content. FTIR analysis confirms the single phase of CoxFe3-xO4 nanoparticles with the major band at 887 cm-1, which might be due to the stretching vibrations of metal-oxide bond. The DSC results corroborate the finding of an increase in the maghemite to hematite phase transition temperature with increase in Co2+ content. The decrease in enthalpy with increase in Co2+ concentration attributed to the fact that the degree of conversion from maghemite to hematite decrease which shows that the stability increases with increasing Co2+ content in B-site of Fe3O4 structure. SEM analysis demonstrated the formation of spherical shaped nanoparticles with least agglomeration. The magnetic measurements enlighten that the coercivity and anisotropy of CoxFe3-xO4 nanoparticles are significantly increased. From UV-Vis analysis it is revealed that band gap energy increases with decreasing particle size. This result has a great interest for magnetic fluid hyperthermia application (MPH).

Low Energy X-Ray and Electron Physics and Technology for High-Temperature Plasma Diagnostics

DTIC Science & Technology

1987-10-01

This program in low-energy x-ray physics and technology has expanded into a major program with the principal objective of supporting research and application programs at the new large x-ray source facilities, particularly the high temperature plasma and synchrotron radiation sources. This program addresses the development of absolute x-ray diagnostics for the fusion energy and x-ray laser research and development. The new laboratory includes five specially designed

The crystal structure of paramagnetic copper(II) oxalate (CuC₂O₄): formation and thermal decomposition of randomly stacked anisotropic nano-sized crystallites.

PubMed

Christensen, Axel Nørlund; Lebech, Bente; Andersen, Niels Hessel; Grivel, Jean-Claude

2014-11-28

Synthetic copper(II) oxalate, CuC2O4, was obtained in a precipitation reaction between a copper(II) solution and an aqueous solution of oxalic acid. The product was identified from its conventional X-ray powder patterns which match that of the copper mineral Moolooite reported to have the composition CuC2O4·0.44H2O. Time resolved in situ investigations of the thermal decomposition of copper(II) oxalate using synchrotron X-ray powder diffraction showed that in air the compound converts to Cu2O at 215 °C and oxidizes to CuO at 345 °C. Thermo gravimetric analysis performed in an inert Ar-gas reveals that the material contains no crystal water and reduces to pure Cu at 295 °C. Magnetic susceptibility measurements in the temperature range from 2 K to 300 K show intriguing paramagnetic behaviour with no sign of magnetic order down to 2 K. A crystal structure investigation is made based on powder diffraction data using one neutron diffraction pattern obtained at 5 K (λ = 1.5949(1) Å) combined with one conventional and two synchrotron X-ray diffraction patterns obtained at ambient temperature using λ = 1.54056, 1.0981 and λ = 0.50483(1) Å, respectively. Based on the X-ray synchrotron data the resulting crystal structure is described in the monoclinic space group P2₁/c (#14) in the P12₁/n1 setting with unit cell parameters a = 5.9598(1) Å, b = 5.6089(1) Å, c = 5.1138 (1) Å, β = 115.320(1)°. The composition is CuC2O4 with atomic coordinates determined by FullProf refinement of the neutron diffraction data. The crystal structure consists of a random stacking of CuC2O4 micro-crystallites where half the Cu-atoms are placed at (2a) and the other half at (2b) positions with the corresponding oxalate molecules centred around the corresponding (2b) and (2a) site positions, respectively. The diffraction patterns obtained for both kinds of radiation show considerable broadening of several Bragg peaks caused by highly anisotropic microstructural size and strain effects. In contrast to the water reported to be present in Moolooite, neither thermogravimetric nor the in situ thermal decomposition investigations and crystal structure analysis of the neutron diffraction data revealed any trace of water. An appendix contains details about the profile parameters for the diffractometers used at the European Synchrotron Radiation Facility and the Institute Max von Laue-Paul Langevin.

Red-emission phosphor's brightness deterioration by x-ray and brightness recovery phenomenon by heating.

PubMed

Nakamura, Masaaki; Chida, Koichi; Inaba, Yohei; Kobayashi, Ryota; Zuguchi, Masayuki

2017-06-26

There are no feasible real-time and direct skin dosimeters for interventional radiology. One would be available if there were x-ray phosphors that had no brightness change caused by x-ray irradiation, but the emission of the Y 2 O 3 :Eu, (Y, Gd, Eu)BO 3 , and YVO 4 :Eu phosphors investigated in our previous study was reduced by x-ray irradiation. We found that the brightness of those phosphors recovered, and the purpose of this study is to investigate their recovery phenomena. It is expected that more kinds of phosphors could be used in x-ray dosimeters if the brightness changes caused by x-rays are elucidated and prevented. Three kinds of phosphors-Y 2 O 3 :Eu, (Y, Gd, Eu)BO 3 , and YVO 4 :Eu-were irradiated by x-rays (2 Gy) to reduce their brightness. After the irradiation, brightness changes occurring at room temperature and at 80 °C were investigated. The irradiation reduced the brightness of all the phosphors by 5%-10%, but the brightness of each recovered immediately both at room temperature and at 80 °C. The recovery at 80 °C was faster than that at room temperature, and at both temperatures the recovered brightness remained at 95%-98% of the brightness before the x-ray irradiation. The brightness recovery phenomena of Y 2 O 3 :Eu, (Y, Gd, Eu)BO 3 , and YVO 4 :Eu phosphors occurring after brightness deterioration due to x-ray irradiation were found to be more significant at 80 °C than at room temperature. More kinds of phosphors could be used in x-ray scintillation dosimeters if the reasons for the brightness changes caused by x-rays were elucidated.

X-ray based extensometry

NASA Technical Reports Server (NTRS)

Jordan, E. H.; Pease, D. M.

1988-01-01

A totally new method of extensometry using an X-ray beam was proposed. The intent of the method is to provide a non-contacting technique that is immune to problems associated with density variations in gaseous environments that plague optical methods. X-rays are virtually unrefractable even by solids. The new method utilizes X-ray induced X-ray fluorescence or X-ray induced optical fluorescence of targets that have melting temperatures of over 3000 F. Many different variations of the basic approaches are possible. In the year completed, preliminary experiments were completed which strongly suggest that the method is feasible. The X-ray induced optical fluorescence method appears to be limited to temperatures below roughly 1600 F because of the overwhelming thermal optical radiation. The X-ray induced X-ray fluorescence scheme appears feasible up to very high temperatures. In this system there will be an unknown tradeoff between frequency response, cost, and accuracy. The exact tradeoff can only be estimated. It appears that for thermomechanical tests with cycle times on the order of minutes a very reasonable system may be feasible. The intended applications involve very high temperatures in both materials testing and monitoring component testing. Gas turbine engines, rocket engines, and hypersonic vehicles (NASP) all involve measurement needs that could partially be met by the proposed technology.

Thermochemical properties of nanometer CL-20 and PETN fabricated using a mechanical milling method

NASA Astrophysics Data System (ADS)

Song, Xiaolan; Wang, Yi; An, Chongwei

2018-06-01

2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and pentaerythritol tetranitrate (PETN), with mean sizes of 73.8 nm and 267.7 nm, respectively, were fabricated on a high-energy ball-mill. Scanning electron microscope (SEM) analysis was used to image the micron-scale morphology of nano-explosives, and the particle size distribution was calculated using the statistics of individual particle sizes obtained from the SEM images. Analyses, such as X-ray diffractometer (XRD), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS), were also used to confirm whether the crystal phase, molecular structure, and surface elements changed after a long-term milling process. The results were as expected. Thermal analysis was performed at different heating rates. Parameters, such as the activation energy (ES), activation enthalpy (ΔH≠), activation free energy (ΔG≠), activation entropy (ΔS≠), and critical temperature of thermal explosion (Tb), were calculated to determine the decomposition courses of the explosives. Moreover, the thermal decomposition mechanisms of nano CL-20 and nano PETN were investigated using thermal-infrared spectrometry online (DSC-IR) analysis, by which their gas products were also detected. The results indicated that nano CL-20 decomposed to CO2 and N2O and that nano PETN decayed to NO2, which implied a remarkable difference between the decomposition mechanisms of the two explosives. In addition, the mechanical sensitivities of CL-20 and PETN were tested, and the results revealed that nano-explosives were more insensitive than raw ones, and the possible mechanism for this was discussed. Thermal sensitivity was also investigated with a 5 s bursting point test, from which the 5 s bursting point (T5s) and the activation of the deflagration were obtained.

High-pressure high-temperature crystal growth of equiatomic rare earth stannides RENiSn and REPdSn

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

Heymann, Gunter; Heying, Birgit; Rodewald, Ute Ch.

2016-04-15

The two series of equiatomic rare earth (RE) stannides RENiSn and REPdSn were systematically studied with respect to high-pressure modifications. The normal-pressure (NP) low-temperature (LT) modifications were synthesized by arc-melting and subsequently treated under high-pressure (P{sub max}=11.5 GPa) and high-temperature (T{sub max}=1570 K) conditions in a Walker-type multi-anvil press. The pressure and temperature conditions were systematically varied in order to improve the crystallization conditions. The new ZrNiAl-type high-pressure modifications HP-RENiSn (RE=Sc, Y, La, Gd–Lu) and HP-REPdSn (RE=Y, Sm–Dy) were obtained in 80 mg quantities, several of them in X-ray pure form. Some of the REPdSn stannides with the heavy raremore » earth elements show high-temperature (HT) modifications. The structures of HP-ScNiSn, HP-GdNiSn, HP-DyNiSn (both ZrNiAl-type), NP-YbNiSn, and HT-ErPdSn (both TiNiSi-type) were refined from single crystal diffractometer data, indicating full ordering of the transition metal and tin sites. TiNiSi-type NP-EuPdSn transforms to MgZn{sub 2}-type HP-EuPdSn: P6{sub 3}/mmc, a=588.5(2), c=917.0(3) pm, wR2=0.0769, 211 F{sup 2} values, 11 variables. The structure refinement indicated statistical occupancy of the palladium and tin sites on the tetrahedral network. The X-ray pure high-pressure phases were studied with respect to their magnetic properties. HP-YPdSn is a Pauli paramagnet. The susceptibility data of HP-TbNiSn, HP-DyNiSn, HP-GdPdSn, and HP-TbPdSn show experimental magnetic moments close to the free ion values of RE{sup 3+} and antiferromagnetic ordering at low temperature with the highest Néel temperature of 15.8 K for HP-TbPdSn. HP-SmPdSn shows the typical Van Vleck type behavior along with antiferromagnetic ordering at T{sub N}=5.1 K. HP-EuPdSn shows divalent europium and antiferromagnetic ordering at 8.9 K followed by a spin reorientation at 5.7 K. - Graphical abstract: Packing of the polyhedra in the high-pressure phase of EuPdSn. - Highlights: • High-pressure phases of the stannides RENiSn and REPdSn. • Crystal growth conditions. • Pressure- and temperature-driven phase transitions. • Magnetic properties.« less

Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit

NASA Astrophysics Data System (ADS)

Huang, B. S.; Yin, W. F.; Sang, D. H.; Jiang, Z. Y.

2012-10-01

The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr5S8 phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

Preparation, crystal structure and thermal decomposition kinetics of 1-(2,4-dinitrophenyl)azo-1-nitrocyclohexane

NASA Astrophysics Data System (ADS)

Yang, Desuo; Ma, Haixia; Hu, Rongzu; Song, Jirong; Zhao, Fengqi

2005-11-01

A new three-nitro-group compound of 1-(2,4-dinitrophenyl)azo-1-nitrocyclohexane was prepared by the reaction of cyclohexanone-2,4-dinitrophenylhydrazine with nitric oxide at ambient temperature. The single crystal structure has been determined by a four-circle X-ray diffractometer. The compound is monoclinic with space group P2(1)/ c and unit-cell parameters a=11.300(2) Å, b=12.993(2) Å, c=10.155(1) Å, β=98.33(1) o, F(000)=672, the unit-cell volume V=1475.2(5) Å 3, the molecule number in one unit-cell Z=4, the absorption coefficient μ=1.19 cm -1, the calculated density Dc=1.456 g cm -3. The exothermic decomposition reaction kinetics of the compound has been studied by DSC. The kinetic model function in differential form, apparent activation energy and pre-exponential constant of this reaction are (3/4)(1-α)[-ln(1-α)] 1/4, 123.88 kJ mol -1 and 10 11.49 s -1, respectively. The critical temperature of thermal explosion of the title compound is 161.15 oC and the entropy of activation (ΔS), enthalpy of activation (ΔH), and free energy of activation (ΔG) are -34.16 J mol -1 K -1, 115.7, and 130.48 kJ mol -1, respectively.

Effect of shot peening on the residual stress and mechanical behaviour of low-temperature and high-temperature annealed martensitic gear steel 18CrNiMo7-6

NASA Astrophysics Data System (ADS)

Yang, R.; Zhang, X.; Mallipeddi, D.; Angelou, N.; Toftegaard, H. L.; Li, Y.; Ahlström, J.; Lorentzen, L.; Wu, G.; Huang, X.

2017-07-01

A martensitic gear steel (18CrNiMo7-6) was annealed at 180 °C for 2h and at ˜ 750 °C for 1h to design two different starting microstructures for shot peening. One maintains the original as-transformed martensite while the other contains irregular-shaped sorbite together with ferrite. These two materials were shot peened using two different peening conditions. The softer sorbite + ferrite microstructure was shot peened using 0.6 mm conditioned cut steel shots at an average speed of 25 m/s in a conventional shot peening machine, while the harder tempered martensite steel was shot peened using 1.5 mm steel shots at a speed of 50 m/s in an in-house developed shot peening machine. The shot speeds in the conventional shot peening machine were measured using an in-house lidar set-up. The microstructure of each sample was characterized by optical and scanning electron microscopy, and the mechanical properties examined by microhardness and tensile testing. The residual stresses were measured using an Xstress 3000 G2R diffractometer equipped with a Cr Kα x-ray source. The correspondence between the residual stress profile and the gradient structure produced by shot peening, and the relationship between the microstructure and strength, are analyzed and discussed.

Paraequilibrium Carburization of Duplex and Ferritic Stainless Steels

NASA Astrophysics Data System (ADS)

Michal, G. M.; Gu, X.; Jennings, W. D.; Kahn, H.; Ernst, F.; Heuer, A. H.

2009-08-01

AISI 301 and E-BRITE stainless steels were subjected to low-temperature (743 K) carburization experiments using a commercial technology developed for carburization of 316 austenitic stainless steels. The AISI 301 steel contained ~40 vol pct ferrite before carburization but had a fully austenitic hardened case, ~20- μm thick, and a surface carbon concentration of ~8 at. pct after treatment; this “colossal” paraequilibrium carbon supersaturation caused an increase in lattice parameter of ~3 pct. The E-BRITE also developed a hardened case, 12- to 18- μm thick, but underwent a more modest (~0.3 pct) increase in lattice parameter; the surface carbon concentration was ~10 at. pct. While the hardened case on the AISI 301 stainless steel appeared to be single-phase austenite, evidence for carbide formation was apparent in X-ray diffractometer (XRD) scans of the E-BRITE. Paraequilibrium phase diagrams were calculated for both AISI 301 and E-BRITE stainless steels using a CALPHAD compound energy-based interstitial solid solution model. In the low-temperature regime of interest, and based upon measured paraequilibrium carbon solubilities, more negative Cr-carbon interaction parameters for austenite than those in the current CALPHAD data base may be appropriate. A sensitivity analysis involving Cr-carbon interaction parameters for ferrite found a strong dependence of carbon solubility on relatively small changes in the magnitude of these parameters.

Small area silicon diffused junction X-ray detectors

NASA Technical Reports Server (NTRS)

Walton, J. T.; Pehl, R. H.; Larsh, A. E.

1982-01-01

The low-temperature performance of silicon diffused junction detectors in the measurement of low energy X-rays is reported. The detectors have an area of 0.04 sq cm and a thickness of 100 microns. The spectral resolutions of these detectors were found to be in close agreement with expected values, indicating that the defects introduced by the high-temperature processing required in the device fabrication were not deleteriously affecting the detection of low-energy X-rays. Device performance over a temperature range of 77 K to 150 K is given. These detectors were designed to detect low-energy X-rays in the presence of minimum ionizing electrons. The successful application of silicon-diffused junction technology to X-ray detector fabrication may facilitate the development of other novel silicon X-ray detector designs.

X-Ray Temperatures, Luminosities, and Masses from XMM-Newton Follow-up of the First Shear-selected Galaxy Cluster Sample

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

Deshpande, Amruta J.; Hughes, John P.; Wittman, David, E-mail: amrejd@physics.rutgers.edu, E-mail: jph@physics.rutgers.edu, E-mail: dwittman@physics.ucdavis.edu

We continue the study of the first sample of shear-selected clusters from the initial 8.6 square degrees of the Deep Lens Survey (DLS); a sample with well-defined selection criteria corresponding to the highest ranked shear peaks in the survey area. We aim to characterize the weak lensing selection by examining the sample’s X-ray properties. There are multiple X-ray clusters associated with nearly all the shear peaks: 14 X-ray clusters corresponding to seven DLS shear peaks. An additional three X-ray clusters cannot be definitively associated with shear peaks, mainly due to large positional offsets between the X-ray centroid and the shearmore » peak. Here we report on the XMM-Newton properties of the 17 X-ray clusters. The X-ray clusters display a wide range of luminosities and temperatures; the L {sub X} − T {sub X} relation we determine for the shear-associated X-ray clusters is consistent with X-ray cluster samples selected without regard to dynamical state, while it is inconsistent with self-similarity. For a subset of the sample, we measure X-ray masses using temperature as a proxy, and compare to weak lensing masses determined by the DLS team. The resulting mass comparison is consistent with equality. The X-ray and weak lensing masses show considerable intrinsic scatter (∼48%), which is consistent with X-ray selected samples when their X-ray and weak lensing masses are independently determined.« less

Fabrication of Glassy and Crystalline Ferroelectric Oxide by Containerless Processing

NASA Astrophysics Data System (ADS)

Yoda, Shinichi

1. Instruction Much effort has been devoted to forming bulk glass from the melt of ferroelectric crystalline materials without adding any network-forming oxides such as SiO2 due to the potential for producing transparent glass ceramics with high dielectric constant and enhanced piezoelectric, pyroelectric and electro-optic effects. However, they require a higher cooling rate than glass formed by conventional techniques. Therefore, only amorphous thin-films have been formed, using rapid quenching with a cooling rate >105 K/s. The containerless processing is an attractive synthesis technique as it can prevent melt contamination, minimize heterogeneous nucleation, and allow melt to achieve deep undercooling for forming metastable phase and glassy material. Recently a new ferroelectric materiel, monoclinic BaTi2 O5 , with Currie temperature as 747 K was reported. In this study, we fabricated a bulk BaTi2 O5 glass from melt using containerless processing to study the phase relations and ferroelectric properties of BaTi2 O5 . To our knowledge, this was the first time that a bulk glass of ferroelectric material was fabricated from melt without adding any network-forming oxide. 2. Experiments BaTi2 O5 sphere glass with 2mm diameter was fabricated using containerless processing in an Aerodynamic Levitation Furnace (ALF). The containerless processing allowed the melt to achieve deep undercooling for glass forming. High purity commercial BaTiO3 and TiO2 powders were mixed with a mole ratio of 1:1 and compressed into rods and then sintered at 1427 K for 10 h. Bulk samples with a mass of about 20 mg were cut from the rod, levitated with the ALF, and then melted by a CO2 laser beam. After quenching with a cooling rate of about 1000 K/s, 2 mm diameter sphere glass could be obtained. To analyze the glass structure, a high-energy x-ray diffraction experiment was performed using an incident photon energy of 113.5 keV at the high-energy x-ray diffraction beamline BL04B2 of SPring-8, with a two-axis diffractometer for the disordered materials. The glass-transition behavior was studied by Differential Scanning Calorimetry (DSC) with a heating rate of 10 K/min from room temperature to 1600 K. The structure changes during heating were characterized by powder x-ray diffraction in the temperature range from room temperature to 1100 K. For electrical property measurements, we cut and ground the samples into disks of 0.3 to 0.4 mm thickness and measured the dielectric constant and impedance from room temperature to 1123 K at a heating rate of 3 K/s using Ag electrodes. 3. Results Above the glass transition temperature (972 K), three successive phase transitions, from glass to a metastable α-phase at 972 K, then to a metastable β-phase at 1038 K, and finally to a stable monoclinic γ-phase above 1100 K, were observed. At the crystallization temperature of α-phase, the permittivity jumped instantaneously by more than one order of magnitude, reaching a peak of 1.4 x 107 . This interesting phenomenon, occurring near the crystallization temperature, has important technical implications for obtaining an excellent dielectric glassceramics through controlled crystallization of BaTi2 O5 glass 504b030414000600080000002100828abc13fa0000001c020000130000005b436f6e74656e745f54797065735d2e78

Ion Storage Ring Measurements of Low Temperature Dielectronic Recombination Rate Coefficients for Modeling X-Ray Photoionized Cosmic Plasmas

NASA Technical Reports Server (NTRS)

Savin, D. W.; Gwinner, G.; Schwalm, D.; Wolf, A.; Mueller, A.; Schippers, S.

2002-01-01

Low temperature dielectronic recombination (DR) is the dominant recombination mechanism for most ions in X-ray photoionized cosmic plasmas. Reliably modeling and interpreting spectra from these plasmas requires accurate low temperature DR rate Coefficients. Of particular importance are the DR rate coefficients for the iron L-shell ions (Fe XVII-Fe XXIV). These ions are predicted to play an important role in determining the thermal structure and line emission of X-ray photoionized plasmas, which form in the media surrounding accretion powered sources such as X-ray binaries (XRBs), active galactic nuclei (AGN), and cataclysmic variables (Savin et al., 2000). The need for reliable DR data of iron L-shell ions has become particularly urgent after the launches of Chandra and XMM-Newton. These satellites are now providing high-resolution X-ray spectra from a wide range of X-ray photoionized sources. Interpreting the spectra from these sources requires reliable DR rate coefficients. However, at the temperatures relevant, for X-ray photoionized plasmas, existing theoretical DR rate coefficients can differ from one another by factors of two to orders of magnitudes.

Reciprocal Space Mapping of Macromolecular Crystals in the Laboratory

NASA Technical Reports Server (NTRS)

Snell, Edward H.; Boggon, T. J.; Fewster, P. F.; Siddons, D. P.; Stojanof, V.; Pusey, M. L.

1998-01-01

The technique of reciprocal space mapping applied to the physical measurement of macromolecular crystals will be described. This technique uses a triple axis diffractometer setup whereby the monochromator is the first crystal, the sample is the second and the third crystal (of the same material as the monochromator) analyzes the diffracted beam. The geometry is such that it is possible to separate mosaic volume effects from lattice strain effects. The deconvolution of the instrument parameters will also be addressed. Results from measurements at Brookhaven National Synchrotron Radiation Source carried out on microgravity and ground-grown crystals will be presented. The required beam characteristics for reciprocal space mapping are also ideal for topographic studies and the first topographs ever recorded from microgravity protein crystal samples will be shown. We are now working on a system which will enable reciprocal space mapping, mosaicity and topography studies to be carried out in the home laboratory. This system uses a rotating anode X-ray source to provide an intense beam then a Bartels double crystal, four reflection monochromator to provide the spectral and geometric beam conditioning necessary such that the instrument characteristics do not mask the measurement. This is coupled to a high precision diffractometer and sensitive detector. Commissioning data and first results from the system will be presented.

Experience with exchange and archiving of raw data: comparison of data from two diffractometers and four software packages on a series of lysozyme crystals.

PubMed

Tanley, Simon W M; Schreurs, Antoine M M; Helliwell, John R; Kroon-Batenburg, Loes M J

2013-02-01

The International Union of Crystallography has for many years been advocating archiving of raw data to accompany structural papers. Recently, it initiated the formation of the Diffraction Data Deposition Working Group with the aim of developing standards for the representation of these data. A means of studying this issue is to submit exemplar publications with associated raw data and metadata. A recent study on the effects of dimethyl sulfoxide on the binding of cisplatin and carboplatin to histidine in 11 different lysozyme crystals from two diffractometers led to an investigation of the possible effects of the equipment and X-ray diffraction data processing software on the calculated occupancies and B factors of the bound Pt compounds. 35.3 Gb of data were transferred from Manchester to Utrecht to be processed with EVAL. A systematic comparison shows that the largest differences in the occupancies and B factors of the bound Pt compounds are due to the software, but the equipment also has a noticeable effect. A detailed description of and discussion on the availability of metadata is given. By making these raw diffraction data sets available via a local depository, it is possible for the diffraction community to make their own evaluation as they may wish.

Highly crumpled solar reduced graphene oxide electrode for supercapacitor application

NASA Astrophysics Data System (ADS)

Mohanapriya, K.; Ahirrao, Dinesh J.; Jha, Neetu

2018-04-01

Highly crumpled solar reduced graphene oxide (CSRGO) was synthesized by simple and rapid method through freezing the solar reduced graphene oxide aqueous suspension using liquid nitrogen and used as electrode material for supercapacitor application. This electrode material was characterized by transmission electron microscope (TEM), X-Ray diffractometer (XRD) and Raman Spectroscopy techniques to understand the morphology and structure. The electrochemical performance was studied by cyclic voltammetry (CV), galvanostatic charge/discharge (CD) and electrochemical impedance spectroscopy (EIS) using 6M KOH electrolyte. The CSRGO exhibit high specifc capacitance of 210.1 F g-1 at the current density of 0.5 A g-1 and shows excellent rate capability. These features make the CSRGO material as promising electrode for high-performance supercapacitors.

Performance of the Taiwan Contract Beamline BL12B2 at SPring-8

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

Tang, M.-T.; Du, C.-H.; Lee, J.-F.

2004-05-12

The recent status of the SPring-8 Taiwan Contract Beamline BL12B2 is reported. The beamline was designed to provide multiple applications for materials and biological researches. It is equipped with four end stations, including an EXAFS station, a Huber 6-circle diffractometer for X-ray scattering, a curved image plate for the studies of powder diffraction, and a station for the protein crystallography. The beamline construction was completed in 2000 and it has been in full speed operation since September 2001. To enhance the focusing capacity, the beamline optics has been modified in 2002 and a gain of factor of 10 in photonmore » flux was consequently obtained at protein crystallography station.« less

Morphological and spectroscopic analysis of cellulose nanocrystals extracted from oil palm empty fruit bunch fiber

NASA Astrophysics Data System (ADS)

Dasan, Y. K.; Bhat, A. H.; Faiz, A.

2015-07-01

This work evaluates the use of oil palm empty fruit bunch (OPEFB) fiber as a source of cellulose to obtain nanocrystalline cellulose (CNC) by acid hydrolysis reaction. The raw OPEFB fibers were pretreated with aqueous Sodium hydroxide at 80°C followed by bleaching treatment and further hydrolyzed with Sulphuric acid at 45°C with limited range of hydrolysis time and acid concentration. The resulting CNC's were characterized for spectroscopic, crystallographic and morphological properties using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometer (XRD), Transmission Electron Microscope (TEM) and Atomic Force Microscopy (AFM). Finding of this study shows that the properties of CNC's are strongly dependent on the hydrolysis time and acid concentration.

Optical Fourier diffractometry applied to degraded bone structure recognition

NASA Astrophysics Data System (ADS)

Galas, Jacek; Godwod, Krzysztof; Szawdyn, Jacek; Sawicki, Andrzej

1993-09-01

Image processing and recognition methods are useful in many fields. This paper presents the hybrid optical and digital method applied to recognition of pathological changes in bones involved by metabolic bone diseases. The trabecular bone structure, registered by x ray on the photographic film, is analyzed in the new type of computer controlled diffractometer. The set of image parameters, extracted from diffractogram, is evaluated by statistical analysis. The synthetic image descriptors in discriminant space, constructed on the base of 3 training groups of images (control, osteoporosis, and osteomalacia groups) by discriminant analysis, allow us to recognize bone samples with degraded bone structure and to recognize the disease. About 89% of the images were classified correctly. This method after optimization process will be verified in medical investigations.

The Development of the Chemin Mineralogy Instrument and Its Deployment on Mars (and Latest Results from the Mars Science Laboratory Rover Curiosity)

NASA Technical Reports Server (NTRS)

Blake, David F.

2014-01-01

The CheMin instrument (short for "Chemistry and Mineralogy") on the Mars Science Laboratory rover Curiosity is one of two "laboratory quality" instruments on board the Curiosity rover that is exploring Gale crater, Mars. CheMin is an X-ray diffractometer that has for the first time returned definitive and fully quantitative mineral identifications of Mars soil and drilled rock. I will describe CheMin's 23-year development from an idea to a spacecraft qualified instrument, and report on some of the discoveries that Curiosity has made since its entry, descent and landing on Aug. 6, 2012, including the discovery and characterization of the first habitable environment on Mars.

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

Yakubovich, O. V., E-mail: yakubol@geol.msu.ru; Biralo, G. V.; Dimitrova, O. V.

The crystal structure of the (Al,V){sub 4}(P{sub 4}O{sub 12}){sub 3} solid solution, obtained in the single-crystal form by hydrothermal synthesis in the Al(OH){sub 3}-VO{sub 2}-NaCl-H{sub 3}PO{sub 4}-H{sub 2}O system, has been solved by X-ray diffraction analysis (Xcalibur-S-CCD diffractometer, R = 0.0257): a = 13.7477(2) Angstrom-Sign , sp. gr. I 4 bar 3d, Z = 4, and {rho}{sub calcd} = 2.736 g/cm{sup 3}. It is shown that the crystal structure of the parent cubic Al{sub 4}(P{sub 4}O{sub 12}){sub 3} modification can formally be considered an archetype for the formation of double isosymmetric tetraphosphates on its basis.

Neutron capillary optics: status and perspectives

NASA Astrophysics Data System (ADS)

Kumakhov, M. A.

2004-08-01

The article is dedicated to the current status of neutron polycapillary optics and its application. X-ray and neutron polycapillary optics was first suggested in my papers published and patented about 20 years ago. The first X-ray lens was made about 20 years ago (in 1985) in my laboratory at the Kurchatov Institute of Atomic Power. The first neutron assembled capillary lens consisting of several thousand polycapillaries was assembled and tested 2 years later at the atomic reactor of the Kurchatov Institute. A great many experiments were done at the atomic reactors in Russia, Germany, France, USA for neutron beam focusing, turning. Most successful were the experiments on turning neutron beam at the atomic reactor in Berlin, where it was possible to turn the neutron beam by the angle of 20°. Numerous experiments in Germany and France proved high efficacy of polycapillary optics in controlling thermal neutron radiation. The article gives new results obtained in creating pure beams of thermal neutrons on the basis of polycapillary optics. New polycapillary technologies developed at IRO, Moscow/Unisantis, Geneva, enable creation of neutron diffractometers, spectrometers, reflectometers, microscopes—all with a micron-size focal spot. All instruments are portable and highly efficient. Such generation of instruments has been already developed and realized for X-rays, and the same process for neutron beams has already started. So, neutron polycapillary optics makes it possible to create new instruments and raise the level of scientific research, and also enables use of neutron beam for industrial application in production environment.

X-Ray Temperatures, Luminosities, and Masses from XMM-Newton Follow-upof the First Shear-selected Galaxy Cluster Sample

NASA Astrophysics Data System (ADS)

Deshpande, Amruta J.; Hughes, John P.; Wittman, David

2017-04-01

We continue the study of the first sample of shear-selected clusters from the initial 8.6 square degrees of the Deep Lens Survey (DLS); a sample with well-defined selection criteria corresponding to the highest ranked shear peaks in the survey area. We aim to characterize the weak lensing selection by examining the sample’s X-ray properties. There are multiple X-ray clusters associated with nearly all the shear peaks: 14 X-ray clusters corresponding to seven DLS shear peaks. An additional three X-ray clusters cannot be definitively associated with shear peaks, mainly due to large positional offsets between the X-ray centroid and the shear peak. Here we report on the XMM-Newton properties of the 17 X-ray clusters. The X-ray clusters display a wide range of luminosities and temperatures; the L X -T X relation we determine for the shear-associated X-ray clusters is consistent with X-ray cluster samples selected without regard to dynamical state, while it is inconsistent with self-similarity. For a subset of the sample, we measure X-ray masses using temperature as a proxy, and compare to weak lensing masses determined by the DLS team. The resulting mass comparison is consistent with equality. The X-ray and weak lensing masses show considerable intrinsic scatter (˜48%), which is consistent with X-ray selected samples when their X-ray and weak lensing masses are independently determined. Some of the data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

Effects of a Ta interlayer on the phase transition of TiSi2 on Si(111)

NASA Astrophysics Data System (ADS)

Jeon, Hyeongtag; Jung, Bokhee; Kim, Young Do; Yang, Woochul; Nemanich, R. J.

2000-09-01

This study examines the effects of a thin Ta interlayer on the formation of TiSi2 on Si(111) substrate. The Ta interlayer was introduced by depositing Ta and Ti films sequentially on an atomically clean Si(111) substrate in an ultrahigh vacuum (UHV) system. Samples of 100 Å Ti with 5 and 10 Å Ta interlayers were compared to similar structures without an interlayer. After deposition, the substrates were annealed for 10 min, in situ, at temperatures between 500 and 750 °C in 50 °C increments. The TiSi2 formation with and without the Ta interlayer was analyzed with an X-ray diffractometer, Auger electron spectroscopy (AES), Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and a four-point probe. The AES analysis data showed a 1:2 ratio of Ti:Si in the Ti-silicide layer and indicated that the Ta layer remained at the interface between TiSi2 and the Si(111) substrate. The C 49-C 54 TiSi2 phase transition temperature was lowered by ˜200 °C. The C 49-C 54 TiSi2 phase transition temperature was 550 °C for the samples with a Ta interlayer and was 750 °C for the samples with no Ta interlayer. The sheet resistance of the Ta interlayered Ti silicide showed lower values of resistivity at low temperatures which indicated the change in phase transition temperature. The C 54 TiSi2 displayed different crystal orientation when the Ta interlayer was employed. The SEM and TEM micrographs showed that the TiSi2 with a Ta interlayer significantly suppressed the tendency to islanding and surface agglomeration.

Green synthesis of Copper nanoparticle using ionic liquid-based extraction from Polygonum minus and their applications.

PubMed

Ullah, Habib; Wilfred, Cecilia Devi; Shaharun, Maizatul Shima

2018-06-06

The present work reports the extraction of phenolic compounds from Polygonum minus using ionic liquid as extracting solvent. In this work, 1-Butyl-3-methylimidazolium hydrogen sulfate [BMIM][HSO 4 ] was used for the extraction of bioactive compounds. Accordingly, ionic liquids based microwave-assisted extraction treatment for separating of bioactive compounds from polygonum minus was first performed in the present study. The results obtained in this work have high extraction yield in comparison with conventional solvent. UV/Vis results showed that microwave synthesis was fast, well dispersed and nanosized copper nanoparticle (CuNPs) in comparison with conventional synthesis. CuNPs was characterized by X-Rays diffractometer (XRD), Fourier transform infrared (FTIR), dynamic light scattering (DLS), field emission scanning electron microscopy combined with energy dispersive x-rays (FESEM-EDX), and thermogravimetric analysis (TGA). All the instrumental analyses confirmed the particles were nanosized. Furthermore, the antibacterial activity of as-synthesized CuNPs showed effective inhibitory zone against three different bacteria. The photocatalytic degradation of copper nanoparticles was studied using methylene blue (MB) and methyl orange (MO) dyes under UV light and degraded 99.9% within short time 8 and 7 minutes.

Activity of plasma sprayed yttria stabilized zirconia reinforced hydroxyapatite/Ti-6Al-4V composite coatings in simulated body fluid.

PubMed

Gu, Y W; Khor, K A; Pan, D; Cheang, P

2004-07-01

Hydroxyapatite (HA)/yttria stabilized zirconia/Ti-6Al-4V bio-composite coatings deposited onto Ti-6Al-4V substrate through a plasma spray technique were immersed in simulated body fluid (SBF) to investigate their behavior in vitro. Surface morphologies and structural changes in the coatings were analyzed by scanning electron microscopy, thin-film X-ray diffractometer, and X-ray photoelectron spectroscopy. The tensile bond strength of the coatings after immersion was also conducted through the ASTM C-633 standard for thermal sprayed coatings. Results showed that carbonate-containing hydroxyapatite (CHA) layer formed on the surface of composite coatings after 4 weeks immersion in SBF solution, indicating the composite coating possessed excellent bioactivity. The mechanical properties were found to decrease with immersion duration of maximum 56 days. However, minimal variation in mechanical properties was found subsequent to achieving supersaturation of the calcium ions, which was attained with the precipitation of the calcium phosphate layers. The mechanical properties of the composite coating were found to be significantly higher than those of pure HA coatings even after immersion in the SBF solution, indicating the enhanced mechanical properties of the composite coatings.

Friction and Wear Properties of CrSiCN/SiC Tribopairs in Water Lubrication

NASA Astrophysics Data System (ADS)

Wu, Zhiwei; Zhou, Fei; Wang, Qianzhi

2018-05-01

CrSiCN coatings (3.4 at.% Si) were prepared on 316L stainless steels using unbalanced magnetron sputtering. According to the analysis results of x-ray diffractometer and x-ray photoelectrons spectroscopy, silicon in CrSiCN coatings mainly presented in the amorphous forms of a-SiN, a-SiCN and a-SiC. The hardness and Young's modulus of CrSiN coatings were 19.4 ± 0.6 and 306.1 ± 5.9 GPa, respectively. In addition, the ball-on-disk sliding tests of CrSiCN/SiC tribopairs were performed in distilled water at varying velocities (0.1-0.5 m/s) and loads (2-12 N). The friction coefficient of tribopairs presented a decreasing trend with respect to velocity at low applied loads (≤ 4 N). To be specific, the low friction coefficient of 0.05-0.14 accompanied with polished wear scar was obtained at high velocities and low loads. Finally, the wear mechanism map of CrSiCN/SiC tribopairs was proposed based on a combination of friction coefficient, wear scar morphology and wear rates of tribopairs.

Corrosion Behavior and Microhardness of Ni-P-SiO2-Al2O3 Nano-composite Coatings on Magnesium Alloy

NASA Astrophysics Data System (ADS)

Sadreddini, S.; Rahemi Ardakani, S.; Rassaee, H.

2017-05-01

In the present work, nano-composites of Ni-P-SiO2-Al2O3 were coated on AZ91HP magnesium alloy. The surface morphology of the nano-composite coating was studied by field emission scanning electron microscopy (FESEM). The amount of SiO2 in the coating was determined by energy-dispersive analysis of x-ray (EDX), and the crystalline structure of the coating was examined by x-ray diffractometer (XRD). All the experiments concerning the corrosion behavior of the coating carried out in 3.5 wt.% NaCl solution and evaluated by electrochemical impedance spectroscopy (EIS) and polarization technique. The results showed that an incorporation of SiO2 and Al2O3 in Ni-P coating at the SiO2 concentration of 10 g/Land 14 g/LAl2O3 led to the lowest corrosion rate ( i corr = 1.3 µA/cm2), the most positive E corr and maximum microhardness (496 VH). Furthermore, Ni-P-SiO2-Al2O3 nano-composite coating possesses less porosity than that in Ni-P coating, resulting in improving corrosion resistance.

Catalytic behavior of a palladium doped binder free paper based cobalt electrode in electroreduction of hydrogen peroxide

NASA Astrophysics Data System (ADS)

Zhang, Dongming; Ye, Ke; Cao, Dianxue; Yin, Jinling; Cheng, Kui; Wang, Bin; Xu, Yang; Wang, Guiling

2015-01-01

A piece of flexible and conductive A4 paper is prepared by coating a layer of graphite with a normal 8B pencil. Then, Co nano-plates and Pd are assembled by a simple electrodeposition and chemical-reduction methods on the surface of the electrified paper, respectively. The as-prepared paper substrate/graphite-Co film-Pd (PG-CoPd) electrode is characterized by scanning electron microscopy equipped with energy dispersive X-ray spectrometer, transmission electron microscope and X-ray diffractometer. The catalytic activity of the PG-CoPd electrode for H2O2 electroreduction is investigated by means of cyclic voltammetry and chronoamperometry. The preparation process of the PG-CoPd electrode does not use any binder and it exhibits a three dimensional (3D) nano structure, high stability and good electric conductivity. The mass of the Pd in PG-CoPd is about 0.0535 mg cm-2 and the reduction current density reaches to -4.30 A cm-2 mg-1 in 1 mol dm-3 NaOH and 1.4 mol dm-3 H2O2 at -0.5 V, which is higher than our previous reports of Au/Pd modified Co electrode.

Deposition of magnesium nitride thin films on stainless steel-304 substrates by using a plasma focus device

NASA Astrophysics Data System (ADS)

Ramezani, Amir Hoshang; Habibi, Maryam; Ghoranneviss, Mahmood

2014-08-01

In this research, for the first time, we synthesize magnesium nitride thin films on 304-type stainless steel substrates using a Mather-type (2 kJ) plasma focus (PF) device. The films of magnesium nitride are coated with different number of focus shots (like 15, 25 and 35) at a distance of 8 cm from the anode tip and at 0° angular position with respect to the anode axis. For investigation of the structural properties and surface morphology of magnesium nitride films, we utilized the X-ray diffractometer (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM) analysis, respectively. Also, the elemental composition is characterized by energy-dispersive X-ray (EDX) analysis. Furthermore, Vicker's microhardness is used to study the mechanical properties of the deposited films. The results show that the degree of crystallinity of deposited thin films (from XRD), the average size of particles and surface roughness (from AFM), crystalline growth of structures (from SEM) and the hardness values of the films depend on the number of focus shots. The EDX analysis demonstrates the existence of the elemental composition of magnesium in the deposited samples.

pH-insusceptible cobalt-manganese immobilizing mesoporous siliceous MCM-41 catalyst for ozonation of dimethyl phthalate.

PubMed

Tang, Yiming; Pan, Zhaoqi; Li, Laisheng

2017-12-15

Mesoporous siliceous MCM-41 immobilized with Co and Mn metal ions (Co-Mn-MCM-41) was synthesized using a hydrothermal method. The structural regularity and the valence states of the metal species were measured by X-ray diffractometer and X-ray photoelectron spectrometer. The resultant bimetallic Co-Mn-MCM-41 catalyst was tested for the degradation of dimethyl phthalate (DMP) via a catalytic ozonation mechanism, demonstrating that the catalytic properties of Co-Mn-MCM-41 catalyst significantly accelerated the ozonation process. Total organic carbon (TOC) and DMP removal efficiency reached 94% and 99.7% at 15min under the optimal conditions. The oxidation pathways were proposed after identifying the intermediate products from ozonation using a gas chromatography-mass spectrometer. The enhanced catalytic reactivity was attributed to the highly-dispersive cobalt and manganese species in MCM-41 scaffolds, which promoted the ozone decomposition and hydroxyl radicals' generation in catalytic ozonation and accelerated the degradation of DMP. Bimetallic Co-Mn-MCM-41 catalyst remained stable in mild acidic conditions and continued to show high activity after repeated runs. Copyright © 2017 Elsevier Inc. All rights reserved.

Electron temperature from x-ray continuum measurements on the NIF

NASA Astrophysics Data System (ADS)

Jarrott, Leonard; Bachmann, Benjamin; Benedetti, Robin; Izumi, Nobuhiko; Khan, Shahab; Landen, Otto; Ma, Tammy; Nagel, Sabrina; Pak, Arthur; Patel, Prav; Schneider, Marilyn; Springer, Paul; LLNL Collaboration

2017-10-01

We report on measurements of the electron temperature within the hot spot of inertially confined, layered implosions on the NIF using a titanium differential filtering x-ray diagnostic. The electron temperature from x-ray emission is insensitive to non-thermal velocity flows as is the case with ion temperature measurements and is thus a critical parameter in interpreting stagnated hot spot conditions. Here we discuss measurements using titanium filters ranging from 10 μm to 1mm in thickness with a sensitivity band of 10-30keV coupled with penumbral pinholes. The use of larger pinhole diameters increases x-ray fluence improving sensitivity of photon energies with minimal attenuation from the compressed fuel/shell. This diagnostic has been fielded on a series of cryogenic shots with DT ion temperatures ranging from 2-5keV. Analysis of the measurement will be presented along with a comparison against simulated electron temperatures and x-ray spectra as well as a comparison to DT ion temperature measurements. This work was performed under the auspices of U.S. DoE by LLNL under Contract No. DE-AC52-07NA27344.

OSO 8 X-ray spectra of clusters of galaxies. I - Observations of twenty clusters: Physical correlations

NASA Technical Reports Server (NTRS)

Mushotzky, R. F.; Serlemitsos, P. J.; Boldt, E. A.; Holt, S. S.; Smith, B. W.

1978-01-01

OSO 8 X-ray spectra from 2 to 20 keV have been analyzed for 26 clusters of galaxies. For 20 clusters temperatures, emission integrals, iron abundances, and low-energy absorption measurements are presented. The data give, in general, better fits to thermal bremsstrahlung than to power-law models. Eight clusters have positive iron emission-line detections at the 90% confidence level, and all 20 cluster spectra are consistent with Fe/H = 0.000014 by number with the possible exception of Virgo. Thus it is confirmed that X-ray emission in this energy band is predominantly thermal radiation from hot intracluster gas rather than inverse Compton radiation. Physical correlations between X-ray spectral parameters and other cluster properties are examined. It is found that (1) the X-ray temperature is approximately proportional to the square of the velocity dispersion of the galaxies; (2) the emission integral is a strong function of the X-ray temperature; (3) the X-ray temperature and emission integral are better correlated with cluster central-galaxy density than with richness; and (4) the fraction of galaxies which are spirals is correlated with the observed ram pressure in the cluster core.

Molybdenum cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures

NASA Astrophysics Data System (ADS)

Matsuda, Kazuhiro; Tamura, Kozaburo; Katoh, Masahiro; Inui, Masanori

2004-03-01

We have developed a sample cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures. All parts of the cell are made of molybdenum which is resistant to the chemical corrosion of alkali metals. Single crystalline molybdenum disks electrolytically thinned down to 40 μm were used as the walls of the cell through which x rays pass. The crystal orientation of the disks was controlled in order to reduce the background from the cell. All parts of the cell were assembled and brazed together using a high-temperature Ru-Mo alloy. Energy dispersive x-ray diffraction measurements have been successfully carried out for fluid rubidium up to 1973 K and 16.2 MPa. The obtained S(Q) demonstrates the applicability of the molybdenum cell to x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures.

Mapping the hot gas temperature in galaxy clusters using X-ray and Sunyaev-Zel'dovich imaging

NASA Astrophysics Data System (ADS)

Adam, R.; Arnaud, M.; Bartalucci, I.; Ade, P.; André, P.; Beelen, A.; Benoît, A.; Bideaud, A.; Billot, N.; Bourdin, H.; Bourrion, O.; Calvo, M.; Catalano, A.; Coiffard, G.; Comis, B.; D'Addabbo, A.; Désert, F.-X.; Doyle, S.; Ferrari, C.; Goupy, J.; Kramer, C.; Lagache, G.; Leclercq, S.; Macías-Pérez, J.-F.; Maurogordato, S.; Mauskopf, P.; Mayet, F.; Monfardini, A.; Pajot, F.; Pascale, E.; Perotto, L.; Pisano, G.; Pointecouteau, E.; Ponthieu, N.; Pratt, G. W.; Revéret, V.; Ritacco, A.; Rodriguez, L.; Romero, C.; Ruppin, F.; Schuster, K.; Sievers, A.; Triqueneaux, S.; Tucker, C.; Zylka, R.

2017-10-01

We propose a method to map the temperature distribution of the hot gas in galaxy clusters that uses resolved images of the thermal Sunyaev-Zel'dovich (tSZ) effect in combination with X-ray data. Application to images from the New IRAM KIDs Array (NIKA) and XMM-Newton allows us to measure and determine the spatial distribution of the gas temperature in the merging cluster MACS J0717.5+3745, at z = 0.55. Despite the complexity of the target object, we find a good morphological agreement between the temperature maps derived from X-ray spectroscopy only - using XMM-Newton (TXMM) and Chandra (TCXO) - and the new gas-mass-weighted tSZ+X-ray imaging method (TSZX). We correlate the temperatures from tSZ+X-ray imaging and those from X-ray spectroscopy alone and find that TSZX is higher than TXMM and lower than TCXO by 10% in both cases. Our results are limited by uncertainties in the geometry of the cluster gas, contamination from kinetic SZ ( 10%), and the absolute calibration of the tSZ map (7%). Investigation using a larger sample of clusters would help minimise these effects.

Densitometry and temperature measurement of combustion gas by X-ray Compton scattering

PubMed Central

Sakurai, Hiroshi; Kawahara, Nobuyuki; Itou, Masayoshi; Tomita, Eiji; Suzuki, Kosuke; Sakurai, Yoshiharu

2016-01-01

Measurement of combustion gas by high-energy X-ray Compton scattering is reported. The intensity of Compton-scattered X-rays has shown a position dependence across the flame of the combustion gas, allowing us to estimate the temperature distribution of the combustion flame. The energy spectra of Compton-scattered X-rays have revealed a significant difference across the combustion reaction zone, which enables us to detect the combustion reaction. These results demonstrate that high-energy X-ray Compton scattering can be employed as an in situ technique to probe inside a combustion reaction. PMID:26917151

Densitometry and temperature measurement of combustion gas by X-ray Compton scattering.

PubMed

Sakurai, Hiroshi; Kawahara, Nobuyuki; Itou, Masayoshi; Tomita, Eiji; Suzuki, Kosuke; Sakurai, Yoshiharu

2016-03-01

Measurement of combustion gas by high-energy X-ray Compton scattering is reported. The intensity of Compton-scattered X-rays has shown a position dependence across the flame of the combustion gas, allowing us to estimate the temperature distribution of the combustion flame. The energy spectra of Compton-scattered X-rays have revealed a significant difference across the combustion reaction zone, which enables us to detect the combustion reaction. These results demonstrate that high-energy X-ray Compton scattering can be employed as an in situ technique to probe inside a combustion reaction.

ROSAT X-ray observations of late-type evolved stars: On the relationship between coronal temperatures and luminosities

NASA Technical Reports Server (NTRS)

Maggio, A.; Sciortino, S.; Harnden, F. R., Jr.

1994-01-01

We present ROSAT Position Sensitive Proportional Counters (PSPC) X-ray observations of three near-solar-mass stars, in different evolutionary phases beyond the main sequence: eta Sco (F3 III-IV), iota Vir (F6 III), and HD 74772 (G5 III). All three of these nearby, presumably single stars have been detected, and we have collected enough counts to perform a detailed analysis of their soft X-ray spectra. While the X-ray spectra of eta Sco and HD 74772 can be fitted with Raymond-Smith thermal models with temperatures around 2 x 10(exp 6) K, the high signal-to-noise spectrum of iota Vir provides unambiguous evidence of a multitemperature plasma, with a two-temperature best-fit model with components at approximately 2 x 10(exp 6) K and 8 x 10(exp 6) K. Evidence of some hot plasma (T approximately 10(exp 7) K) has been also found for HD 74772. The present data, compared with spectral fitting results for other late-type stars observed with the Einstein Observatory, indicate that the low X-ray luminosity giants (L(sub x) is less than 5 x 10(exp 28) ergs/s) do not share with the higher X-ray luminosity stars of the same class the property of having substantial amount of 10(exp 7) K plasma. Moreover, our results confirm the trend of increasing X-ray luminosities with increasing coronal temperatures.

X-ray and radio observations of flares from the RS Canum Venaticorum system UX ARIETIS

NASA Astrophysics Data System (ADS)

Tsuru, T.; Makishima, K.; Ohashi, T.; Inoue, H.; Koyama, K.; Turner, M. J. L.; Barstow, M. A.; McHardy, I. M.; Pye, J. P.; Tsunemi, H.; Kitamoto, S.; Taylor, A. R.; Nelson, R. F.

In July 1987 the RS CVn system UX Ari was observed in the 2-20-keV X-ray band by Ginga, immediately followed by 5-GHz radio observations. UX Ari was found to be very active at both radio and X-ray frequencies. Quiescent X-ray emission with a luminosity of 3 x 10 to the 31st erg/s (in the 2-20-keV band) was detected, together with two intense X-ray flares up to 2 x 10 to the 32nd and 6 x 10 to the 31st erg/s, respectively. Both flare and quiescent X-ray spectra are well fitted by single-temperature thermal bremsstrahlung models, with the continuum temperature and emission measure in the range 4-7 kev (in kT) and (2-10) x 10 to the 54th/cu cm, respectively.

Thermal stabilization of neutron Larmor diffractometers

NASA Astrophysics Data System (ADS)

Keller, T.; Tralmer, F.

2017-06-01

We report on the design of a support unit for the radio frequency (RF) coils of a Larmor diffractometer (LD) eliminating fluctuations of the Larmor phase resulting from thermal expansion of the support structures. The key component defining the spacing between the RF coils is a Zerodur bar with a very low thermal expansion coefficient (α = 7 × 10-8 K-1). This support unit will allow for LD measurements on the 10-6 accuracy level even if the ambient temperature is fluctuating.

Morphological and spectroscopic analysis of cellulose nanocrystals extracted from oil palm empty fruit bunch fiber

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

Dasan, Y. K., E-mail: aamir.bhat@petronas.com.my; Bhat, A. H., E-mail: aamir.bhat@petronas.com.my; Faiz, A., E-mail: faizahmad@petronas.com.my

2015-07-22

This work evaluates the use of oil palm empty fruit bunch (OPEFB) fiber as a source of cellulose to obtain nanocrystalline cellulose (CNC) by acid hydrolysis reaction. The raw OPEFB fibers were pretreated with aqueous Sodium hydroxide at 80°C followed by bleaching treatment and further hydrolyzed with Sulphuric acid at 45°C with limited range of hydrolysis time and acid concentration. The resulting CNC’s were characterized for spectroscopic, crystallographic and morphological properties using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffractometer (XRD), Transmission Electron Microscope (TEM) and Atomic Force Microscopy (AFM). Finding of this study shows that the properties of CNC’s aremore » strongly dependent on the hydrolysis time and acid concentration.« less

Dye-Sensitized Solar Cells (DSSCs) reengineering using TiO2 with natural dye (anthocyanin)

NASA Astrophysics Data System (ADS)

Subodro, Rohmat; Kristiawan, Budi; Ramelan, Ari Handono; Wahyuningsih, Sayekti; Munawaroh, Hanik; Hanif, Qonita Awliya; Saputri, Liya Nikmatul Maula Zulfa

2017-01-01

This research on Dye-Sensitized Solar Cells (DSSCs) reengineering was carried out using TiO2 with natural dye (anthocyanin). The fabrication of active carbon layer/TiO2 DSSC solar cell was based on natural dye containing anthocyanins such as mangosteen peel, red rose flower, black glutinous rice, and purple eggplant peel. DSSC was prepared with TiO2 thin layer doped with active carbon; Natural dye was analyzed using UV-Vis and TiO2 was analyzed using X-ray diffractometer (XRD), meanwhile scanning electron microscope (SEM) was used to obtain the size of the crystal. Keithley instrument test was carried out to find out I-V characteristics indicating that the highest efficiency occurred in DSSCs solar cell with 24-hour soaking with mangosteen peel 0.00047%.

Growing barium hexaferrite (BaFe{sub 12}O{sub 19}) thin films using chemical solution deposition

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

Budiawanti, Sri, E-mail: awanty77@yahoo.com; Faculty of Teacher Training and Education, Sebelas Maret University; Soegijono, Bambang

Barium hexaferrite (BaFe{sub 12}O{sub 19}, or simply known as BaM) thin films has been recognized as a potential candidate for microwave-based devices, magnetic recording media and data storage. To grow BaM thin films, chemical solution deposition is conducted using the aqueous solution of metal nitrates, which involves spin coatings on Si substrates. Furthermore, Thermal Gravimeter Analysis (TGA), X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM) are applied to evaluate the decomposition behavior, structure, morphology, and magnetic properties of BaM thin films. Additionally, the effects of number of layers variation are also investigated. Finally, magnetic properties analysismore » indicates the isotropic nature of the films.« less

Crystal structure and magnetic properties of Cr doped barium hexaferrite

NASA Astrophysics Data System (ADS)

Kumar, Sunil; Supriya, Sweety; Pandey, Rabichandra; Pradhan, Lagen Kumar; Kar, Manoranjan

2018-04-01

The Cr3+ substituted BaFe12O19 has been synthesized by modified sol-gel method to tailor the magnetic anisotropy and coercivity for technological applications. Some basic studies have revealed that this substitution leads to unusual interactions among the magnetic sublattices of the M-type hexaferrite. In order to investigate these interactions, BaFe12-xCrxO19 (x = 0.0, 0.5, 1.0, 2.0, and 4.0) M-type hexaferrites were characterized by employing XRD (X-ray Diffractometer). It is confirmed that, all the samples are in nanocrystalline and single phase, no impurity has been detected within the XRD limit. The magnetic hysteresis (m-H) loops revealed the ferromagnetic nature of nanoparticles (NPs). The coercive field were increasing with the increasing Cr3+ content, but after the percolation limit it decreases. The magnetocrystalline anisotropy is increasing with the Cr3+ concentration in samples and high values of magnetocrystalline anisotropy revealed that all samples are hard magnetic materials. Magnetic hysteresis loops were analyzed using the Law of Approach to Saturation method.

Morphological and Wear behaviour of new Al-SiCmicro-SiCnano hybrid nanocomposites fabricated through powder metallurgy

NASA Astrophysics Data System (ADS)

Arif, Sajjad; Tanwir Alam, Md; Aziz, Tariq; Ansari, Akhter H.

2018-04-01

In the present work, aluminium matrix composites reinforced with 10 wt% SiC micro particles along with x% SiC nano particles (x = 0, 1, 3, 5 and 7 wt%) were fabricated through powder metallurgy. The fabricated hybrid composites were characterized by x-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrum (EDS) and elemental mapping. The relative density, hardness and wear behaviour of all hybrid nanocomposites were studied. The influence of various control factors like SiC reinforcement, sliding distance (300, 600, 900 and 1200 m) and applied load (20, 30 and 40 N) were explored using pin-on-disc wear apparatus. The uniform distribution of micro and nano SiC particles in aluminium matrix is confirmed by elemental maps. The hardness and wear test results showed that properties of the hybrid composite containing 5 wt% nano SiC was better than other hybrid composites. Additionally, the wear loss of all hybrid nanocomposites increases with increasing sliding distance and applied load. The identification of wear phenomenon were studied through the SEM images of worn surface.

Empirical studies of solar flares: Comparison of X-ray and H alpha filtergrams and analysis of the energy balance of the X-ray plasma

NASA Technical Reports Server (NTRS)

Moore, R. L.

1979-01-01

The physics of solar flares was investigated through a combined analysis of X-ray filtergrams of the high temperature coronal component of flares and H alpha filtergrams of the low temperature chromospheric component. The data were used to study the magnetic field configuration and its changes in solar flares, and to examine the chromospheric location and structure of X-ray bright points (XPB) and XPB flares. Each topic and the germane data are discussed. The energy balance of the thermal X-ray plasma in flares, while not studied, is addressed.

In situ investigation of the formation and metastability of formamidinium lead tri-iodide perovskite solar cells

DOE PAGES

Aguiar, Jeffery A.; Wozny, Sarah; Holesinger, Terry George; ...

2016-05-23

Organic–inorganic perovskites have emerged as an important class of next generation solar cells due to their remarkably low cost, band gap, and sub-900 nm absorption onset. Here, we show a series of in situ observations inside electron microscopes and X-ray diffractometers under device-relevant synthesis conditions focused on revealing the crystallization process of the formamidinium lead-triiodide perovskite at the optimum temperature of 175 °C. Direct in situ observations of the structure and chemistry over relevant spatial, temporal, and temperature scales enabled identification of key perovskite formation and degradation mechanisms related to grain evolution and interface chemistry. The lead composition was observedmore » to fluctuate at grain boundaries, indicating a mobile lead-containing species, a process found to be partially reversible at a key temperature of 175 °C. Using low energy electron microscopy and valence electron energy loss spectroscopy, lead is found to be bonded in the grain interior with iodine in a tetrahedral configuration. At the grain boundaries, the binding energy associated with lead is consequently shifted by nearly 2 eV and a doublet peak is resolved due presumably to a greater degree of hybridization and the potential for several different bonding configurations. At the grain boundaries there is adsorption of hydrogen and OH¯ ions as a result of residual water vapor trapped as a non-crystalline material during formation. Lastly, insights into the relevant formation and decomposition reactions of formamidinium lead iodide at low to high temperatures, observed metastabilities, and relationship with the photovoltaic performance were obtained and used to optimize device processing resulting in conversion efficiencies of up to 17.09% within the stability period of the devices.« less

In situ investigation of the formation and metastability of formamidinium lead tri-iodide perovskite solar cells

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

Aguiar, Jeffery A.; Wozny, Sarah; Holesinger, Terry G.

2016-01-01

Organic-inorganic perovskites have emerged as an important class of next generation solar cells due to their remarkably low cost, band gap, and sub-900 nm absorption onset. Here, we show a series of in situ observations inside electron microscopes and X-ray diffractometers under device-relevant synthesis conditions focused on revealing the crystallization process of the formamidinium lead-triiodide perovskite at the optimum temperature of 175 degrees C. Direct in situ observations of the structure and chemistry over relevant spatial, temporal, and temperature scales enabled identification of key perovskite formation and degradation mechanisms related to grain evolution and interface chemistry. The lead composition wasmore » observed to fluctuate at grain boundaries, indicating a mobile lead-containing species, a process found to be partially reversible at a key temperature of 175 degrees C. Using low energy electron microscopy and valence electron energy loss spectroscopy, lead is found to be bonded in the grain interior with iodine in a tetrahedral configuration. At the grain boundaries, the binding energy associated with lead is consequently shifted by nearly 2 eV and a doublet peak is resolved due presumably to a greater degree of hybridization and the potential for several different bonding configurations. At the grain boundaries there is adsorption of hydrogen and OH- ions as a result of residual water vapor trapped as a non-crystalline material during formation. Insights into the relevant formation and decomposition reactions of formamidinium lead iodide at low to high temperatures, observed metastabilities, and relationship with the photovoltaic performance were obtained and used to optimize device processing resulting in conversion efficiencies of up to 17.09% within the stability period of the devices.« less

Discovery of X-ray emission associated with the Gum Nebula

NASA Technical Reports Server (NTRS)

Leahy, D. A.; Nousek, J.; Garmire, G.

1992-01-01

The Gum Nebula was observed by the A-2 LED proportional counters on the HEAO-1 satellite as part of the all-sky survey. The first detection of X-ray emission associated with the Gum Nebula is reported. Soft X-ray spectra were constructed from the A-2 LED PHA data. Single temperature Raymond-Smith models were fitted to the observed spectra to yield temperature, column density and emission measure. The temperature is 6 x 10 exp 5 K, the column density 4 x 10 exp 20/sq cm, and the emission measure 5 cm exp-6 pc. The X-ray and optical properties of the Gum Nebula are consistent with a supernova remnant in the shell stage of evolution, which was the product of an energetic (3 x 10 exp 51 ergs) supernova explosion which occurred about 2 x 10 exp 6 yr ago.

First-principles calculations of K-shell X-ray absorption spectra for warm dense nitrogen

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

Li, Zi; Zhang, Shen; Kang, Wei

2016-05-15

X-ray absorption spectrum is a powerful tool for atomic structure detection on warm dense matter. Here, we perform first-principles molecular dynamics and X-ray absorption spectrum calculations on warm dense nitrogen along a Hugoniot curve. From the molecular dynamics trajectory, the detailed atomic structures are examined for each thermodynamical condition. The K-shell X-ray absorption spectrum is calculated, and its changes with temperature and pressure along the Hugoniot curve are discussed. The warm dense nitrogen systems may contain isolated nitrogen atoms, N{sub 2} molecules, and nitrogen clusters, which show quite different contributions to the total X-ray spectrum due to their different electronmore » density of states. The changes of X-ray spectrum along the Hugoniot curve are caused by the different nitrogen structures induced by the temperature and the pressure. Some clear signatures on X-ray spectrum for different thermodynamical conditions are pointed out, which may provide useful data for future X-ray experiments.« less

Fabrication and characterization of environmental-friendly Ni1-xRxTiO3 nanopigments with high NIR reflectance

NASA Astrophysics Data System (ADS)

Tong, Yu-Ping; Chen, Zheng; Wang, Hui-Xian; Zhang, Xu-Fang; Ma, Jun-Tao; Chen, Xi

2015-04-01

A series of novel high dispersed environmental-friendly nanopigments based on NiTiO3 doped with rare earth ion such as Y, La, Eu, Sm have been developed. The products were characterized by X-ray diffractometer (XRD), scanning electron microscopy (SEM), commission internationale de l'Eclairage (CIE) 1976 L*α*b* color scales and UV-Vis-near-infrared radiation (NIR) reflectance spectroscopy. The substitution of R3+ for Ni2+ in NiTiO3 can improve the yellowness of pigments, especially for Eu3+ substitution. The sample with the substitution of Eu3+ for Ni2+ processes the highest NIR reflectance and enhances the NIR reflectance to 89.0%. SEM results revealed that the obtained pigments were composed of well-dispersed spherical-like particles with the range of 40-60 nm. EDS results indicated that the distribution of Ni, Ti, R, O element was considerably uniform with no chemical segregation phenomenon.

X-ray Thomson scattering measurement of temperature in warm dense carbon

DOE PAGES

Falk, Katerina; Fryer, C. L.; Gamboa, E. J.; ...

2016-11-22

Here, a novel platform to measure the equation of state using a combination of diagnostics, where the spectrally resolved x-ray Thomson scattering (XRTS) is used to obtain accurate temperature measurements of warm dense matter (WDM) was developed for the OMEGA laser facility. OMEGA laser beams have been used to drive strong shocks in carbon targets creating WDM and generating the Ni He-alpha x-ray probe used for XRTS. Additional diagnostics including x-ray radiography, velocity interferometry and streaked optical pyrometry provided complementary measurements of density and pressure. The WDM regime of near solid density and moderate temperatures (1–100 eV) is a challengingmore » yet important area of research in inertial confinement fusion and astrophysics. This platform has been used to study off-Hugoniot states of shock-released diamond and graphite at pressures between 1 and 10 Mbar and temperatures between 5 and 15 eV as well as first x-ray Thomson scattering data from shocked low density CH foams reaching five times compression and temperatures of 20–30 eV.« less

Rosat observations of FK comae berenices

NASA Technical Reports Server (NTRS)

Welty, Alan D.; Ramsey, Lawrence W.

1994-01-01

We obtained ROSAT PSPC observations of FK Com over a period of 24.4 h, or 0.42 rotation. During the observations the x-ray flux increased by a factor of at least 5 before declining toward its previous level. A single temperature Raymond-Smith model is adequate to model the low signal-to-noise ratio spectrum from each observation interval. Initially the spectrum was that of a 8.5 x 10(exp 6) K plasma, with L9sub x)=0.66 x 10(exp 31) erg s(exp -1). When the x-ray flux was greatest, the model plasma temperature rose to 2.5 x 10(exp 7) K, and L(sub x)=3.46 x 10(exp 31) ergs(exp -1). During the post-maximum decline in luminosity the plasma temperature was approximately 12 x 10(exp 6) K. We conclude that the increase of x-ray flux recorded by ROSAT was due to an x-ray flare with a 1.5 h decline time scale.

Bioleaching combined brine leaching of heavy metals from lead-zinc mine tailings: Transformations during the leaching process.

PubMed

Ye, Maoyou; Yan, Pingfang; Sun, Shuiyu; Han, Dajian; Xiao, Xiao; Zheng, Li; Huang, Shaosong; Chen, Yun; Zhuang, Shengwei

2017-02-01

During the process of bioleaching, lead (Pb) recovery is low. This low recovery is caused by a problem with the bioleaching technique. This research investigated the bioleaching combination of bioleaching with brine leaching to remove heavy metals from lead-zinc mine tailings. The impact of different parameters were studied, including the effects of initial pH (1.5-3.0) and solid concentration (5-20%) for bioleaching, and the effects of sodium chloride (NaCl) concentration (10-200 g/L) and temperature (25 and 50 °C) for brine leaching. Complementary characterization experiments (Sequential extraction, X-ray diffractometer (XRD), scanning electronic microscope (SEM)) were also conducted to explore the transformation of tailings during the leaching process. The results showed that bioleaching efficiency was significantly influenced by initial pH and solid concentration. Approximately 85.45% of iron (Fe), 4.12% of Pb, and 97.85% of zinc (Zn) were recovered through bioleaching in optimum conditions. Increasing the brine concentration and temperature promoted lead recovery. Lead was recovered from the bioleaching residues at a rate of 94.70% at 25 °C and at a rate of 99.46% at 50 °C when the NaCl concentration was 150 g/L. The study showed that bioleaching significantly changed the speciation of heavy metals and the formation and surface morphology of tailings. The metals were mainly bound in stable fractions after bioleaching. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of Ca/P concentration and temperature of simulated body fluid on the growth of hydroxyapatite coating on alkali-treated 316L stainless steel.

PubMed

Lin, Feng-Huei; Hsu, Yao-Shan; Lin, Shih-Hsun; Sun, Jui-Sheng

2002-10-01

316L-SS is one of the important materials both in orthopaedics and dentistry for bone screw/plate, intra-medullary rod, fixation wire, HIP joint, and knee joint. However, the biocompatibility and bone-bonding ability troubled researches for years. In the study, a simple chemical method was tried so as to establish and induce a bioactive HA layer on the surface of 316L stainless steel. When the metallic substrates treated with 10 M NaOH aqueous solution and subsequently heated at 600 degrees C, a thin sodium chromium oxide layer was formed on the surfaces as the linking layer for HA and 316L-SS. After 316L-SS treated with alkali solution, it would soak into a simulated body fluid with higher concentration of calcium and phosphorous ions to increase the possibility of nucleation of HA. However, the iron oxide and iron chromium oxides were formed on the surface when calcium and phosphorous ions increased. This resulted in loosening the HA layer. When the alkali-treated 316L-SS was soaked into SBF at a temperature of 80 degrees C, it could form a dense and uniform bone-like hydroxyapatite layer on the surface. In the research, the mechanism of the formation of sodium chromium oxide and HA would also be described by the analysis of X-ray diffractometer, scanning electron microscope, energy-dispersion spectrophotometer, and Fourier transformation infrared.

Subresolution Fibrillation in X-Ray Microflares Observed by Yohkoh SXT

NASA Technical Reports Server (NTRS)

Moore, Ron; Falconer, David; Porter, Jason

1999-01-01

We analyze the cooling of the X-ray plasma in microflares observed in active regions by the Yohkoh Soft X-ray Telescope (SXT). A typical microflare appears to be a transient brightening of an entire small magnetic loop, often having a diameter near the limit of resolution (approx. 2 x 10(exp 8) cm). The plasma heated to X-ray temperatures in the body of the loop cools by emission of XUV radiation and by heat conduction to the cooler plasma at the feet of the loop. The cooling rate is determined by the plasma temperature and density and the loop length. The plasma density is determined from the observed X-ray brightness of the loop in combination with the temperature, the loop diameter, and the filling factor. The filling factor is the volume fraction of the loop occupied by the subset of magnetic tubes that is fluid by the X-ray plasma and that contains practically all of the X-ray plasma present in the microflare loop. Taking typical values from the hundreds of microflares measured by Shimizu (X-ray brightness through the thin aluminum filter - 4 x 10(exp 3) DN/s/pixeL lifetime approx. 5 min, temperature approx. 6 x 10(exp 6) K, loop length approx. 10(exp 9) cm, loop diameter approx. 3 x 10(exp 8) cm), we find that for filling factors greater than approx. 1%: (1) the cooling time is much shorter than the duration of the microflare, and (2) conductive cooling strongly dominates over radiative cooling. Because the cooling time is so short and because the conductive heat flux goes mainly into increasing the plasma density via chromospheric evaporation, we are compelled to conclude that: (1) heating to X-ray temperatures continues through nearly the entire lifetime of the microflare, (2) die heating keeps changing to different field lines, so that any one magnetic tube in the sequence of heated tubes emits X-rays only briefly in the life of the microflare, and (3) at any instant during the microflare the tubes filled with X-ray plasma occupy only a small fraction (approx. 10%) of the microflare loop. Hence, we expect that coronal X-ray images with spatial resolution 2-3 times better than from the Yohkoh SXT will show plenty of rapidly changing filamentary substructure in microflares. Our results also suggest that the heating in microflares may result from progressive reconnection similar to that inferred in many larger flares.

X-Ray study of hetero ring flexibility in norbornane, norbornene-fused 1,3-oxazin-2-thiones Structure of 5,8-methano- r-4-phenyl-c-4a, c-5,6,7, c-8, c- 8a-hexahydro-4H- 1 ,3-benzoxazin-2 (3H)-thione

NASA Astrophysics Data System (ADS)

Kálmán, A.; Argay, Gy.; Stájer, G.; Bernáth, G.

1991-08-01

The structure of S,8-methano- r-4-phenyl c4a, c5,6,7 c8 c8ahexahydro4 H 1,3 -benzoxazin- 2 (3 H)-thione (C 15H 17N0S, M r=259.37) has been established by X-ray crystallography from diffractometer data: it crystallizes in the monoclinic space group P2 1/n with a=6.150(2) Å, b=9.655(1) Å, c=22.093(4) Å,β=96.75(2)† V=1302.7(8) Å 3,4,D c=1.32gcm -3and p( Cu K) =20.4cm -. The structure has been solved by direct methods, refined to R=0.050 for 2193 observed reflections. The X-ray analysis substantiated the structure: the NMR spectra in- dicated that the 4-phenyl group assumes an exo-equatorial position. The puckering parameters of D. Cremer, J.A. Pople, J. Am. Chem. Soc., 97 (1975), 1354 (ref.1), of the distorted hetero ring (a transitional form between E 4-envelope, ( 5S 4-screw-boat) show that, depending on the positions of the hetero atoms, both the norbornane, norbornene skeletons markedly alter the characteristic transitional ( 5E/ 5H 6) shape of the 1,3-oxazine ring observed in other saturated, partly saturated l,3-benzoxazin-2-ones, analogous thiones.

Band alignment of atomic layer deposited MgO/Zn0.8Al0.2O heterointerface determined by charge corrected X-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Yan, Baojun; Liu, Shulin; Yang, Yuzhen; Heng, Yuekun

2016-05-01

Pure magnesium (MgO) and zinc oxide doped with aluminum oxide (Zn0.8Al0.2O) were prepared via atomic layer deposition. We have studied the structure and band gap of bulk Zn0.8Al0.2O material by X-ray diffractometer (XRD) and Tauc method, and the band offsets and alignment of atomic layer deposited MgO/Zn0.8Al0.2O heterointerface were investigated systematically using X-ray photoelectron spectroscopy (XPS) in this study. Different methodologies, such as neutralizing electron gun, the use of C 1s peak recalibration and zero charging method, were applied to recover the actual position of the core levels in insulator materials which were easily influenced by differential charging phenomena. Schematic band alignment diagram, valence band offset (ΔEV) and conduction band offset (ΔEC) for the interface of the MgO/Zn0.8Al0.2O heterostructure have been constructed. An accurate value of ΔEV = 0.72 ± 0.11 eV was obtained from various combinations of core levels of heterojunction with varied MgO thickness. Given the experimental band gaps of 7.83 eV for MgO and 5.29 eV for Zn0.8Al0.2O, a type-II heterojunction with a ΔEC of 3.26 ± 0.11 eV was found. Band offsets and alignment studies of these heterojunctions are important for gaining deep consideration to the design of various optoelectronic devices based on such heterointerface.

Surface properties, crystallinity and optical properties of anodised titanium in mixture of β-glycerophosphate (β-GP) and calcium acetate (CA)

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

Chuan, Lee Te, E-mail: gd130079@siswa.uthm.edu.my; Abdullah, Hasan Zuhudi, E-mail: hasan@uthm.edu.my; Idris, Maizlinda Izwana, E-mail: izwana@uthm.edu.my

Anodic oxidation is an electrochemical method for the production of ceramic films on a metallic substrate. It had been widely used to deposit the ceramic coatings on the metals surface. This method has been widely used in surface modification of biomaterials especially for dental implants. In this study, the surface morphology, crystallinity and optical properties of titanium foil was modified by anodising in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA). The experiments were carried out at high voltage (350 V), different anodising time (5 and 10 minutes) and current density (10-70 mA.cm{sup −2}) at room temperature. Anodisedmore » titanium was characterised by using field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), and UV-Vis spectrometry. The result of the experiment showed that surface morphology, crystallinity and optical properties depended strongly on the current density and anodising time. More porous surface and large amount of anatase and rutile was produced at higher current density and longer anodising time. Apart from that, it is also revealed that the energy band gap of anodised titanium increases as the increase in current density due to the presence of anatase and rutile TiO{sub 2}.« less

Preparation and characterization of magnetic core-shell iron oxide@glycyrrhizic acid nanoparticles in ethanol-water mixed solvent

NASA Astrophysics Data System (ADS)

Saeedi, Mostafa; Vahidi, Omid

2018-06-01

In this research, we used the co-precipitation method to synthesize glycyrrhizic acid coated iron oxide magnetic nanoparticles. The aim of this study is to investigate how different amounts of glycyrrhizic acid affect the structural, biological, magnetic, and hyperthermic characteristics of the synthesized magnetic nanoparticles. The synthesis was conducted under different glycyrrhizic acid concentrations in water with the presence of ethanol to generate coated nanoparticles with different amounts of coating agent. The characteristics of the synthesized nanoparticles were examined by several devices including X-ray diffractometer, transmission electron microscope, field-emission scanning electron microscope, vibrating sample magnetometer, Fourier transform infrared spectra, and thermal gravimetric analyzer. The cytotoxicity of synthesized nanoparticles was examined by MTT assay using L929 fibroblast cell line. The results indicated the enhanced biocompatibility of the coated iron oxide nanoparticles due to the presence of glycyrrhizic acid. The comparison of the coated samples shows that the samples with higher amounts of coating agent were more biocompatible. The possibility of using the synthesized magnetic nanoparticles for medical hyperthermia was examined by performing hyperthermia process on a nanofluid made up of the nanoparticles dispersed in water using a high-frequency alternating magnetic field generator and the results confirm the effectiveness of the synthesized nanoparticles in the elevation of the solutions temperature.

Investigation of magnetic properties on spin-ordering effects of FeGa2S4 and FeIn2S4

NASA Astrophysics Data System (ADS)

Myoung, Bo Ra; Lim, Jung Tae; Kim, Chul Sung

2017-09-01

We have studied crystal and magnetic properties of chalcogenides FeGa2S4 and FeIn2S4 with X-ray diffractometer (XRD), magnetic property measurement system (MPMS), magnetometer, physical property measurement system (PPMS), and Mössbauer spectrometer. The crystal structure has 2-dimension triangular lattice structure with P-3m1 of FeGa2S4, while FeIn2S4 has inverse spinel with space group Fd3m. The AC magnetic susceptibility measurements show that FeGa2S4 is an insulating spin glass material, exhibiting geometrical frustration, unlike in the antiferromagnetic [AFM] metallic spin glass FeIn2S4. From hysteresis (M-H) curves at 4.2 K, FeGa2S4 has spin-flop behavior with an angle of 120° of triangle, as against linear slope of FeIn2S4 due to anti-parallel spin. The gap energy by splitting of 5T2g, Δ1 and electric quadrupole splitting ΔEQ of FeIn2S4 are much higher than that of FeGa2S4 at 4.2 K because FeGa2S4 is geometrically frustrated magnet having degenerate ground state at low temperature.

Surface properties, crystallinity and optical properties of anodised titanium in mixture of β-glycerophosphate (β-GP) and calcium acetate (CA)

NASA Astrophysics Data System (ADS)

Chuan, Lee Te; Abdullah, Hasan Zuhudi; Idris, Maizlinda Izwana

2015-07-01

Anodic oxidation is an electrochemical method for the production of ceramic films on a metallic substrate. It had been widely used to deposit the ceramic coatings on the metals surface. This method has been widely used in surface modification of biomaterials especially for dental implants. In this study, the surface morphology, crystallinity and optical properties of titanium foil was modified by anodising in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA). The experiments were carried out at high voltage (350 V), different anodising time (5 and 10 minutes) and current density (10-70 mA.cm-2) at room temperature. Anodised titanium was characterised by using field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), and UV-Vis spectrometry. The result of the experiment showed that surface morphology, crystallinity and optical properties depended strongly on the current density and anodising time. More porous surface and large amount of anatase and rutile was produced at higher current density and longer anodising time. Apart from that, it is also revealed that the energy band gap of anodised titanium increases as the increase in current density due to the presence of anatase and rutile TiO2.

X-ray Scintillation in Lead Halide Perovskite Crystals

PubMed Central

Birowosuto, M. D.; Cortecchia, D.; Drozdowski, W.; Brylew, K.; Lachmanski, W.; Bruno, A.; Soci, C.

2016-01-01

Current technologies for X-ray detection rely on scintillation from expensive inorganic crystals grown at high-temperature, which so far has hindered the development of large-area scintillator arrays. Thanks to the presence of heavy atoms, solution-grown hybrid lead halide perovskite single crystals exhibit short X-ray absorption length and excellent detection efficiency. Here we compare X-ray scintillator characteristics of three-dimensional (3D) MAPbI3 and MAPbBr3 and two-dimensional (2D) (EDBE)PbCl4 hybrid perovskite crystals. X-ray excited thermoluminescence measurements indicate the absence of deep traps and a very small density of shallow trap states, which lessens after-glow effects. All perovskite single crystals exhibit high X-ray excited luminescence yields of >120,000 photons/MeV at low temperature. Although thermal quenching is significant at room temperature, the large exciton binding energy of 2D (EDBE)PbCl4 significantly reduces thermal effects compared to 3D perovskites, and moderate light yield of 9,000 photons/MeV can be achieved even at room temperature. This highlights the potential of 2D metal halide perovskites for large-area and low-cost scintillator devices for medical, security and scientific applications. PMID:27849019

Effect of insulator sleeve material on the x-ray emission from a plasma focus device

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

Hussain, S.; Badar, M. A.; Shafiq, M.

The effect of insulator sleeve material on x-ray emission from a 2.3 kJ Mather type plasma focus device operated in argon-hydrogen mixture is investigated. The time and space resolved x-ray emission characteristics are studied by using a three channel p-i-n diode x-ray spectrometer and a multipinhole camera. The x-ray emission depends on the volumetric ratio of argon-hydrogen mixture as well as the filling pressure and the highest x-ray emission is observed for a volumetric ratio 40% Ar to 60%H{sub 2} at 2.5 mbar filling pressure. The fused silica insulator sleeve produces the highest x-ray emission whereas nonceramic insulator sleeves suchmore » as nylon, Perspex, or Teflon does not produce focus or x-rays. The pinhole images of the x-ray emitting zones reveal that the contribution of the Cu K{alpha} line is weak and plasma x-rays are intense. The highest plasma electron temperature is estimated to be 3.3 and 3.6 keV for Pyrex glass and fused silica insulator sleeves, respectively. It is speculated that the higher surface resistivity of fused silica is responsible for enhanced x-ray emission and plasma electron temperature.« less

Temperature dependence of field-responsive mechanisms in lead zirconate titanate

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

Chung, Ching-Chang; Fancher, Chris M.; Isaac, Catherine

2017-05-17

An electric field loading stage was designed for use in a laboratory diffractometer that enables in situ investigations of the temperature dependence in the field response mechanisms of ferroelectric materials. The stage was demonstrated in this paper by measuring PbZr 1-xTi xO 3 (PZT) based materials—a commercially available PZT and a 1% Nb-doped PbZr 0.56Ti 0.44O 3 (PZT 56/44)—over a temperature range of 25°C to 250°C. The degree of non-180° domain alignment (η 002) of the PZT as a function of temperature was quantified. η 002 of the commercially available PZT increases exponentially with temperature, and was analyzed as amore » thermally activated process as described by the Arrhenius law. The activation energy for thermally activated domain wall depinning process in PZT was found to be 0.47 eV. Additionally, a field-induced rhombohedral to tetragonal phase transition was observed 5°C below the rhombohedral-tetragonal transition in PZT 56/44 ceramic. The field-induced tetragonal phase fraction was increased 41.8% after electrical cycling. Finally, a large amount of domain switching (η 002=0.45 at 1.75 kV/mm) was observed in the induced tetragonal phase.« less

Evidence that the X-Ray Plasma in Microflares is in a Sequence of Subresolution Magnetic Tubes

NASA Technical Reports Server (NTRS)

Moore, Ronald L.; Falconer, D. A.; Porter, Jason G.

1998-01-01

We analyze the cooling of the X-ray emitting thermal plasma in microflares observed in active regions by the Yohkoh Soft X-ray Telescope. A typical microflare appears to be a transient brightening of an entire small magnetic loop, often having a diameter near the limit of resolution (approximately 2 x 10(exp 8) cm) (Shimizu 1995, PASJ, 47, 251). The X-ray plasma in the loop cools by emission of XUV radiation and by heat conduction to the cooler plasma at the feet of the loop. The cooling rate is determined by the plasma temperature and density and the loop length. The plasma density is determined from the observed X-ray brightness of the loop in combination with the temperature, the loop diameter, and the filling factor. The filling factor is the volume fraction of the loop occupied by the subset of magnetic tubes that is filled by the X-ray plasma and that contains practically all of the X-ray plasma present in the microflare loop. Taking typical values from the hundreds of microflares measured by Shimizu (1995) (X-ray brightness through the thin aluminum filter approximately 4 x 10(exp 3) DN/s/pixel, lifetime approximately 5 min, temperature approximately 6 x 10(exp 6) K, loop length approximately 10(exp 9) cm, loop diameter approximately 3 x 10(exp 8) cm), we find that for filling factors greater than approximately 1% (1) the cooling time is much shorter than the duration of the microflare, and (2) conductive cooling strongly dominates over radiative cooling. Because the cooling time is so short and because the conductive heat flux goes mainly into increasing the plasma density via chromospheric evaporation, we are compelled to conclude that (1) heating to X-ray temperatures continues through nearly the entire life of a microflare, (2) the heating keeps changing to different field lines, so that any one magnetic tube in the sequence of heated tubes emits X-rays only briefly in the life of the microflare, and (3) at any instant during the microflare the tubes filled with X-ray plasma occupy only a small fraction (less than approximately 10%) of the microflare loop. Hence, we expect that coronal X-ray images with spatial resolution 2-3 times better than from Yohkoh will show plenty of rapidly changing filamentary substructure in microflares.

Simultaneous SMM flat crystal spectrometer and Very Large Array observations of solar active regions

NASA Technical Reports Server (NTRS)

Lang, Kenneth R.; Willson, Robert F.; Smith, Kermit L.; Strong, Keith T.

1987-01-01

High-resolution images of the quiescent emission from two solar active regions at 20 cm (VLA) and soft X-ray (SMM FCS) wavelengths are compared. There are regions where the X-ray coronal loops have been completely imaged at 20 cm wavelength. In other regions, the X-ray radiation was detected without detectable 20 cm radiation, and vice versa. The X-ray data were used to infer average electron temperatures of about 3-million K and average electron densities of about 2.5 x 10 to the 9th/cu cm for the X-ray emitting plasma in the two active regions. The thermal bremsstrahlung of the X-ray emitting plasma is optically thin at 20 cm wavelength. The 20 cm brightness temperatures were always less than T(e), which is consistent with optically thin bremsstrahlung. The low T(B) can be explained if a higher, cooler plasma covers the hotter X-ray emitting plasma. Thermal gyroresonance radiation must account for the intense 20 cm radiation near and above sunspots where no X-ray radiation is detected.

a Study of the Synchrotron Laue Method for Quantitative Crystal Structure Analysis.

NASA Astrophysics Data System (ADS)

Gomez de Anderez, Dora M.

1990-01-01

Available from UMI in association with The British Library. Quantitative crystal structure analyses have been carried out on small molecule crystals using synchrotron radiation and the Laue method. A variety of single crystal structure determinations and associated refinements are used and compared with the monochromatic analyses. The new molecular structure of 7-amino-5-bromo -4-methyl-2-oxo-1,2,3,4-tetrahidro-1, 6 -naphthyridine-8-carbonitrile (C_{10 }H_9ON_4 Br.H_2O) has been determined, first using monochromatic Mo Kalpha radiation and a four-circle diffractometer, then using synchrotron Laue diffraction photography. The structure refinements showed a R-factor of 4.97 and 14.0% for the Mo Kalpha and Laue data respectively. The molecular structure of (S)-2-chloro-2-fluoro-N-((S)-1-phenylethyl) ethanamide, (C_{10}H _{11}ClFNO), has been determined using the same crystal throughout for X-ray monochromatic analyses (Mo Kalpha and Cu K alpha) followed by synchrotron Laue data collection. The Laue and monochromatic data compare favourably. The R -factors (on F) were 6.23, 6.45 and 8.19% for the Mo K alpha, Cu Kalpha and Laue data sets respectively. The molecular structure of 3-(5-hydroxy-3-methyl-1-phenylpyrazol-4-yl)-1,3-diphenyl -prop- 2-en-1-one, (C_{25 }H_{20}N _2O_2) has been determined using the synchrotron Laue method. The results compare very well with Mo Kalpha monochromatic data. The R-factors (on F) were 4.60 and 5.29% for Mo Kalpha and Laue analysis respectively. The Laue method is assessed in locating the 20 hydrogen atoms in this structure. The structure analysis of the benzil compound ((C_6H_5 O.CO_2)) is carried out using the synchrotron Laue method firstly at room temperature and secondly at low temperature -114 ^circC. The structure shows an R-factor (on F) of 13.06% and 6.85% for each data set respectively. The synchrotron Laue method was used to collect data for ergocalciferol (Vitamin D_2). The same crystal was also used to record oscillation data with the synchrotron radiation monochromatic beam. A new molecular structure of (Dinitrato-(N,N ^'-dimethylethylene-diamine)copper(II)) has been determined using Mo Kalpha radiation on a four circle diffractometer. The refinement resulted in an R-factor (on F) of 4.06%.

A Study of the Synchrotron Laue Method for Quantitative Crystal Structure Analysis

NASA Astrophysics Data System (ADS)

Gomez de Anderez, Dora M.

1990-01-01

Quantitative crystal structure analyses have been carried out on small molecule crystals using synchrotron radiation and the Laue method. A variety of single crystal structure determinations and associated refinements are used and compared with the monochromatic analyses. The new molecular structure of 7-amino-5-bromo -4-methyl-2-oxo-1,2,3,4 -tetrahidro-1,6 -naphthyridine-8-carbonitrile (C_{10 }H_9ON_4 BrcdotH_2O) has been determined, first using monochromatic Mo K alpha radiation and a four-circle diffractometer, then using synchrotron Laue diffraction photography. The structure refinements showed an R-factor of 4.97 and 14.0% for the Mo Kalpha and Laue data respectively. The molecular structure of (S)-2-chloro-2-fluoro-N-((S)-1-phenylethyl) ethanamide, (C_{10}H _{11}ClFNO), has been determined using the same crystal throughout for X-ray monochromatic analyses (Mo Kalpha and Cu K alpha) followed by synchrotron Laue data collection. The Laue and monochromatic data compare favourably. The R -factors (on F) were 6.23, 6.45 and 8.19% for the Mo K alpha, Cu Kalpha and Laue data sets respectively. The molecular structure of 3-(5-hydroxy-3-methyl-1-phenylpyrazol-4-yl)-1,3-diphenyl -prop-2-en-1-one, (C_{25}H _{20}N_2 O_2) has been determined using the synchrotron Laue method. The results compare very well with Mo Kalpha monochromatic data. The R-factors (on F) were 4.60 and 5.29% for Mo Kalpha and Laue analyses respectively. The Laue method is assessed in locating the 20 hydrogen atoms in this structure. The structure analyses of the benzil compound ((C_6H_5 OcdotCO_2)) is carried out using the synchrotron Laue method firstly at room temperature and secondly at low temperature. The structure shows an R-factor (on F) of 13.06% and 6.85% for each data set respectively. The synchrotron Laue method was used to collect data for ergocalciferol (Vitamin D_2). The same crystal was also used to record oscillation data with the synchrotron radiation monochromatic beam. A new molecular structure of (Dinitrato-(N,N ^'-dimethylethylene-diamine)copper(II)) has been determined using Mo Kalpha radiation on a four circle diffractometer. The refinement resulted in an R-factor (on F) of 4.06%.

X-Ray Calorimeter Arrays for Astrophysics

NASA Technical Reports Server (NTRS)

Kilbourne, Caroline A.

2009-01-01

High-resolution x-ray spectroscopy is a powerful tool for studying the evolving universe. The grating spectrometers on the XMM and Chandra satellites started a new era in x-ray astronomy, but there remains a need for instrumentation that can provide higher spectral resolution with high throughput in the Fe-K band (around 6 keV) and can enable imaging spectroscopy of extended sources, such as supernova remnants and galaxy clusters. The instrumentation needed is a broad-band imaging spectrometer - basically an x-ray camera that can distinguish tens of thousands of x-ray colors. The potential benefits to astrophysics of using a low-temperature calorimeter to determine the energy of an incident x-ray photon via measurement of a small change in temperature was first articulated by S. H. Moseley over two decades ago. In the time since, technological progress has been steady, though full realization in an orbiting x-ray telescope is still awaited. A low-temperature calorimeter can be characterized by the type of thermometer it uses, and three types presently dominate the field. The first two types are temperature-sensitive resistors - semiconductors in the metal-insulator transition and superconductors operated in the superconducting-normal transition. The third type uses a paramagnetic thermometer. These types can be considered the three generations of x-ray calorimeters; by now each has demonstrated a resolving power of 2000 at 6 keV, but only a semiconductor calorimeter system has been developed to spaceflight readiness. The Soft X-ray Spectrometer on Astro-H, expected to launch in 2013, will use an array of silicon thermistors with I-IgTe x-ray absorbers that will operate at 50 mK. Both the semiconductor and superconductor calorimeters have been implemented in small arrays, kilo-pixel arrays of the superconducting calorimeters are just now being produced, and it is anticipated that much larger arrays will require the non-dissipative advantage of magnetic thermometers.

Soft X-ray results from the Wisconsin experiment on OSO-8

NASA Technical Reports Server (NTRS)

Bunner, A. N.

1978-01-01

Design features and capabilities of a soft X-ray instrument aboard OSO 8 are discussed, and results are presented for observations of AM Her, Her X-1, and Eta Car. The observations of AM Her indicate that: (1) the spectrum is composite, with a very steep or very-low-temperature component plus a rather flat or very-high-temperature component; (2) the relative phase of soft X-ray minimum and optical V-band primary minimum has remained stable over the interval between 1975 'high-state' observations and 1976 'low-state' observations; and (3) the times of soft X-ray minima and hard X-ray maxima coincide, to within the accuracy of the observations. For Her X-1, soft X-ray turn-on is found to lag behind hard X-ray turn-on by no more than 3 hr. It is suggested that little or no absorption of the soft X-ray component occurs during the on state by cool gas within the Her X-1 system. A strong source with a spectrum peaked between 0.4 and 1.5 keV has been detected which is consistent with a point source at the position of Eta Car.

A novel sol-gel-derived calcium silicate cement with short setting time for application in endodontic repair of perforations

PubMed Central

Lee, Bor-Shiunn; Lin, Hong-Ping; Chan, Jerry Chun-Chung; Wang, Wei-Chuan; Hung, Ping-Hsuan; Tsai, Yu-Hsin; Lee, Yuan-Ling

2018-01-01

Mineral trioxide aggregate (MTA) is the most frequently used repair material in endodontics, but the long setting time and reduced mechanical strength in acidic environments are major shortcomings. In this study, a novel sol-gel-derived calcium silicate cement (sCSC) was developed using an initial Ca/Si molar ratio of 3, with the most effective mixing orders of reactants and optimal HNO3 catalyst volumes. A Fourier transform infrared spectrometer, scanning electron microscope with energy-dispersive X-ray spectroscopy, and X-ray powder diffractometer were used for material characterization. The setting time, compressive strength, and microhardness of sCSC after hydration in neutral and pH 5 environments were compared with that of MTA. Results showed that sCSC demonstrated porous microstructures with a setting time of ~30 min, and the major components of sCSC were tricalcium silicate, dicalcium silicate, and calcium oxide. The optimal formula of sCSC was sn200, which exhibited significantly higher compressive strength and microhardness than MTA, irrespective of neutral or pH 5 environments. In addition, both sn200 and MTA demonstrated good biocompatibility because cell viability was similar to that of the control. These findings suggest that sn200 merits further clinical study for potential application in endodontic repair of perforations. PMID:29386894

A novel sol-gel-derived calcium silicate cement with short setting time for application in endodontic repair of perforations.

PubMed

Lee, Bor-Shiunn; Lin, Hong-Ping; Chan, Jerry Chun-Chung; Wang, Wei-Chuan; Hung, Ping-Hsuan; Tsai, Yu-Hsin; Lee, Yuan-Ling

2018-01-01

Mineral trioxide aggregate (MTA) is the most frequently used repair material in endodontics, but the long setting time and reduced mechanical strength in acidic environments are major shortcomings. In this study, a novel sol-gel-derived calcium silicate cement (sCSC) was developed using an initial Ca/Si molar ratio of 3, with the most effective mixing orders of reactants and optimal HNO 3 catalyst volumes. A Fourier transform infrared spectrometer, scanning electron microscope with energy-dispersive X-ray spectroscopy, and X-ray powder diffractometer were used for material characterization. The setting time, compressive strength, and microhardness of sCSC after hydration in neutral and pH 5 environments were compared with that of MTA. Results showed that sCSC demonstrated porous microstructures with a setting time of ~30 min, and the major components of sCSC were tricalcium silicate, dicalcium silicate, and calcium oxide. The optimal formula of sCSC was sn200, which exhibited significantly higher compressive strength and microhardness than MTA, irrespective of neutral or pH 5 environments. In addition, both sn200 and MTA demonstrated good biocompatibility because cell viability was similar to that of the control. These findings suggest that sn200 merits further clinical study for potential application in endodontic repair of perforations.

Effect of Nano-TiC Dispersed Particles and Electro-Codeposition Parameters on Morphology and Structure of Hybrid Ni/TiC Nanocomposite Layers.

PubMed

Benea, Lidia; Celis, Jean-Pierre

2016-04-06

This research work describes the effect of dispersed titanium carbide (TiC) nanoparticles into nickel plating bath on Ni/TiC nanostructured composite layers obtained by electro-codeposition. The surface morphology of Ni/TiC nanostructured composite layers was characterized by scanning electron microscopy (SEM). The composition of coatings and the incorporation percentage of TiC nanoparticles into Ni matrix were studied and estimated by using energy dispersive X-ray analysis (EDX). X-ray diffractometer (XRD) has been applied in order to investigate the phase structure as well as the corresponding relative texture coefficients of the composite layers. The results show that the concentration of nano-TiC particles added in the nickel electrolyte affects the inclusion percentage of TiC into Ni/TiC nano strucured layers, as well as the corresponding morphology, relative texture coefficients and thickness indicating an increasing tendency with the increasing concentration of nano-TiC concentration. By increasing the amount of TiC nanoparticles in the electrolyte, their incorporation into nickel matrix also increases. The hybrid Ni/nano-TiC composite layers obtained revealed a higher roughness and higher hardness; therefore, these layers are promising superhydrophobic surfaces for special application and could be more resistant to wear than the pure Ni layers.

Solid State Reaction Synthesis of Si-HA as Potential Biomedical Material: An Endeavor to Enhance the Added Value of Indonesian Mineral Resources

NASA Astrophysics Data System (ADS)

Hartatiek; Yudyanto; Ratnasari, S. D.; Windari, R. Y.; Hidayat, N.

2017-05-01

In recent years, one of the most prominently investigated materials is hydroxyapatite (HA). It is because of its excellent properties for medical applications, essentially related to orthopedic. Also, the introduction of other materials to HA becomes another research focus of many leading scientists. In this present study, silicon with various concentrations was introduced, by means of solid state reaction route, to HA forming Si-HA. The crystal structure properties of the as-prepared samples were evaluated by X-ray diffractometer (XRD). Fourier Transform Infra Red (FTIR) spectroscopy data collection and analysis were done to investigate the functional groups within the samples. The microstructural characteristics as well as elemental mapping of the samples were captured by scanning electron microscopy and energy dispersive x-ray spectroscopy (SEM-EDX). Vickers hardness test was also conducted to investigate the hardness properties of the samples. Furthermore, in vitro characterization-based bio resorbability of the samples in a simulated body fluid were also described. This study revealed that Indonesian limestone can be utilized as the raw material for synthesizing HA. The silicon has been successfully incorporated into phosphate site of the HA crystal. Conclusively, the Si-HA reported in this study shows good bioresorbability characteristic.

Growth and characterization of novel organic 3-Hydroxy Benzaldehyde-N-methyl 4 Stilbazolium Tosylate crystals for NLO applications.

PubMed

Jagannathan, K; Umarani, P; Ratchagar, V; Ramesh, V; Kalainathan, S

2016-01-15

The 3-Hydroxy Benzaldehyde-N-methyl 4-Stilbazolium Tosylate (3- HBST) is a new organic NLO crystal and it is a new derivative in stilbazolium tosylate family. In this work we have synthesized 3-HBST and the single crystal was grown by conventional slow cooling method. The structure and lattice parameters of the grown crystal were determined by the single crystal X-ray diffraction (XRD) technique and it is exhibiting good crystalline nature which is observed from the powder XRD. In order to check the crystalline quality the rocking curve was recorded using multi crystal X-ray diffractometer. The functional groups were identified from both FTIR and NMR spectral analyses. The π-π* and n-π* optical transition energy levels were estimated from the absorption peaks. The NLO property was confirmed by measuring relative SHG efficiency by Kurtz powder test; it shows 24 times higher SHG efficiency than that of urea. In order to test the mechanical stability the Vickers and Knoop micro hardness measurement were carried out and found that the micro hardness number decreases with increasing load. The melting point was determined from Differential Scanning Colorimetry (DSC). Copyright © 2015 Elsevier B.V. All rights reserved.

Stereostructure of a norbornane diexo-condensed 1,3-oxazine[2,3-a]isoindolone An X-ray study

NASA Astrophysics Data System (ADS)

Argay, Gy.; Kálmán, A.; Stájer, G.; Bernáth, G.

1994-12-01

The structure of 3,6-methano-12b-p-tolyl-2a,3,4,5,6,6a,7,12b-octahydro-2H-3,1-benzoxazino[2,3-a]isoindol-8-one (C23H23NO2, Mr = 345.42), prepared from 2-p-toluoylbenzoic acid and diexo-3-hydroxymethylbicyclo[2.2.1]heptyl-2-amine, has been established by X-ray crystallography from diffractometer data: it crystallizes in the triclinic space group Poverline1 with a = 8.186(2) Å, b = 8.683(2) Å, c = 13.324(5) Å, α = 83.46(4)°, β = 75.48(6)°, γ = 77.60(4)°, V = 893.6(4) Å3, Z = 2, Dc = 1.284 g cm-3 and μ(Cu Kα) = 0.641 mm-1. The structure was solved by direct methods and refined to R = 0.061 for 3685 observed reflections. The molecule exhibits diexo-annelation between the 1,3-oxazine ring and the norbornane moiety. The p-tolyl group and norbonane annelation hydrogens are trans and the 1,3-oxazine ring is fused to an almost planar γ-lactam ring. Consequently, the six-membered hetero ring assumes an irregular conformation among the canonical forms 1S6, 1T3 and B3,6.

Berberine and zinc oxide-based nanoparticles for the chemo-photothermal therapy of lung adenocarcinoma.

PubMed

Kim, Sungyun; Lee, Song Yi; Cho, Hyun-Jong

2018-05-16

Organic/inorganic hydrid nanoparticles (NPs) composed of berberine (BER) and zinc oxide (ZnO) were developed for the therapy of lung cancers. Without the use of pharmaceutical excipients, NPs were fabricated with only dual anticancer agents (BER and ZnO) by facile blending method. The mean weight ratio between BER and ZnO in BER-ZnO NPs was 39:61 in this study. BER-ZnO NPs dispersed in water exhibited 200-300 nm hydrodynamic size under 5 mg/mL concentration. The exposure of both BER and ZnO in the outer layers of BER-ZnO NPs was identified by X-ray photoelectron spectroscopy analysis. The amorphization of BER and the maintenance of ZnO structure were observed in the results of X-ray powder diffractometer analysis. Improved antiproliferation efficacy, based on the chemo-photothermal therapeutic efficacy, of BER-ZnO NPs in A549 (human lung adenocarcinoma) cells was presented. According to the blood tests in rats after intravenous administration, BER-ZnO NPs did not induce severe hepatotoxicity, renal toxicity, and hemotoxicity. Developed BER-ZnO NPs can be used efficiently and safely for the chemo-photothermal therapy of lung cancers. Copyright © 2018 Elsevier Inc. All rights reserved.

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

Broadbridge, Christine C.

DOE grant used for partial fulfillment of necessary laboratory equipment for course enrichment and new graduate programs in nanotechnology at the four institutions of the Connecticut State University System (CSUS). Equipment in this initial phase included variable pressure scanning electron microscope with energy dispersive x-ray spectroscopy elemental analysis capability [at Southern Connecticut State University]; power x-ray diffractometer [at Central Connecticut State University]; a spectrophotometer and spectrofluorimeter [at Eastern Connecticut State University; and a Raman Spectrometer [at Western Connecticut State University]. DOE's funding was allocated for purchase and installation of this scientific equipment and instrumentation. Subsequently, DOE funding was allocated tomore » fund the curriculum, faculty development and travel necessary to continue development and implementation of the System's Graduate Certificate in Nanotechnology (GCNT) program and the ConnSCU Nanotechnology Center (ConnSCU-NC) at Southern Connecticut State University. All of the established outcomes have been successfully achieved. The courses and structure of the GCNT program have been determined and the program will be completely implemented in the fall of 2013. The instrumentation has been purchased, installed and has been utilized at each campus for the implementation of the nanotechnology courses, CSUS GCNT and the ConnSCU-NC. Additional outcomes for this grant include curriculum development for non-majors as well as faculty and student research.« less

X-ray imaging for studying behavior of liquids at high pressures and high temperatures using Paris-Edinburgh press.

PubMed

Kono, Yoshio; Kenney-Benson, Curtis; Shibazaki, Yuki; Park, Changyong; Wang, Yanbin; Shen, Guoyin

2015-07-01

Several X-ray techniques for studying structure, elastic properties, viscosity, and immiscibility of liquids at high pressures have been integrated using a Paris-Edinburgh press at the 16-BM-B beamline of the Advanced Photon Source. Here, we report the development of X-ray imaging techniques suitable for studying behavior of liquids at high pressures and high temperatures. White X-ray radiography allows for imaging phase separation and immiscibility of melts at high pressures, identified not only by density contrast but also by phase contrast imaging in particular for low density contrast liquids such as silicate and carbonate melts. In addition, ultrafast X-ray imaging, at frame rates up to ∼10(5) frames/second (fps) in air and up to ∼10(4) fps in Paris-Edinburgh press, enables us to investigate dynamics of liquids at high pressures. Very low viscosities of melts similar to that of water can be reliably measured. These high-pressure X-ray imaging techniques provide useful tools for understanding behavior of liquids or melts at high pressures and high temperatures.

The Chandra M10l Megasecond: Diffuse Emission

NASA Technical Reports Server (NTRS)

Kuntz, K. D.; Snowden, S. L.

2009-01-01

Because MIOl is nearly face-on, it provides an excellent laboratory in which to study the distribution of X-ray emitting gas in a typical late-type spiral galaxy. We obtained a Chandra observation with a cumulative exposure of roughly 1 Ms to study the diffuse X-ray emission in MlOl. The bulk of the X-ray emission is correlated with the star formation traced by the FUV emission. The global FUV/Xray correlation is non-linear (the X-ray surface brightness is roughly proportional to the square root of the FUV surface brightness) and the small-scale correlation is poor, probably due to the delay between the FUV emission and the X-ray production ill star-forming regions. The X-ray emission contains only minor contributions from unresolved stars (approximates less than 3%), unresolved X-ray point sources (approximates less than 4%), and individual supernova remnants (approximates 3%). The global spectrum of the diffuse emission can be reasonably well fitted with a three component thermal model, but the fitted temperatures are not unique; many distributions of emission measure can produce the same temperatures when observed with the current CCD energy resolution. The spectrum of the diffuse emission depends on the environment; regions with higher X-ray surface brightnesses have relatively stronger hard components, but there is no significant evidence that the temperatures of the emitting components increase with surface brightness.

A high-temperature furnace for in situ synchrotron X-ray spectroscopy under controlled atmospheric conditions.

PubMed

Eeckhout, Sigrid Griet; Gorges, Bernard; Barthe, Laurent; Pelosi, Orietta; Safonova, Olga; Giuli, Gabriele

2008-09-01

A high-temperature furnace with an induction heater coil has been designed and constructed for in situ X-ray spectroscopic experiments under controlled atmospheric conditions and temperatures up to 3275 K. The multi-purpose chamber design allows working in backscattering and normal fluorescence mode for synchrotron X-ray absorption and emission spectroscopy. The use of the furnace is demonstrated in a study of the in situ formation of Cr oxide between 1823 K and 2023 K at logPO(2) values between -10.0 and -11.3 using X-ray absorption near-edge spectroscopy. The set-up is of particular interest for studying liquid metals, alloys and other electrically conductive materials under extreme conditions.

X-ray Survey of Centaurus A.

PubMed

Byram, E T; Chubb, T A; Friedman, H

1970-07-24

An x-ray survey of Centaurus A has given marginal evidence of its x-ray flux. If taken as an upper limit on inverse Compton x-rays generated by scattering interactions between relativistic electrons and cosmological background photons, the observation implies an upper limit of close to 3 degrees K for the background radiation temperature.

Diagnosis of a two wire X-pinch by X-ray absorption spectroscopy utilizing a doubly curved ellipsoidal crystal

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

Cahill, A. D., E-mail: adc87@cornell.edu; Hoyt, C. L., E-mail: adc87@cornell.edu; Shelkovenko, T. A., E-mail: adc87@cornell.edu

2014-12-15

X-ray absorption spectroscopy is a powerful tool for the diagnosis of plasmas over a wide range of both temperature and density. However, such a measurement is often limited to probing plasmas with temperatures well below that of the x-ray source in order to avoid object plasma emission lines from obscuring important features of the absorption spectrum. This has excluded many plasmas from being investigated by this technique. We have developed an x-ray spectrometer that provides the ability to record absorption spectra from higher temperature plasmas than the usual approach allows without the risk of data contamination by line radiation emittedmore » by the plasma under study. This is accomplished using a doubly curved mica crystal which is bent both elliptically and cylindrically. We present here initial absorption spectra obtained from an aluminum x-pinch plasma.« less

Observations of low-luminosity X-ray sources in Vela-Puppis

NASA Technical Reports Server (NTRS)

Pravdo, S. H.; Becker, R. H.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Swank, J. H.

1978-01-01

Results are presented for a study of the X-ray emission from a small portion of the galactic plane near galactic longitude 260 deg. This region contains at least six low-luminosity X-ray sources within about 10 deg of PSR 0833-45, which is near the center of the Gum nebula. The X-ray source 4U 0833-45, associated with the Vela pulsar, is observed at twice its 4U catalog intensity. The lack of X-ray pulsations at the pulsar period (greater than 99% nonpulsed), the nonthermal power-law spectrum, and models of the X-ray source distribution in this region suggest that a large fraction of the X-rays come from an extended source about 1 deg of arc in radius. The observation of a high-temperature (effective temperature at least 100 million K) spectrum in a field of view containing only Puppis A among known sources has led to the discovery of new OSO 8 source, OS 0752-39. Other spectra from this region are discussed.

A series of shocks and edges in Abell 2219

DOE PAGES

Canning, R. E. A.; Allen, S. W.; Applegate, D. E.; ...

2016-09-22

Here, we present deep, 170 ks, Chandra X-ray observations of Abell 2219 (z = 0.23), one of the hottest and most X-ray luminous clusters known, and which is experiencing a major merger event. We discover a ‘horseshoe’ of high-temperature gas surrounding the ram-pressure-stripped, bright, hot, X-ray cores. We confirm an X-ray shock front located north-west of the X-ray centroid and along the projected merger axis. We also find a second shock front to the south-east of the X-ray centroid making this only the second cluster where both the shock and reverse shock are confirmed with X-ray temperature measurements. We alsomore » present evidence for a possible sloshing cold front in the ‘remnant tail’ of one of the sub-cluster cores. The cold front and north-west shock front geometrically bound the radio halo and appear to be directly influencing the radio properties of the cluster.« less

X-ray Thomson scattering measurements from hohlraum-driven spheres on the OMEGA laser [X-ray Thomson scattering measurements from hohlraum targets on the OMEGA laser

DOE PAGES

Saunders, A. M.; Jenei, A.; Doppner, T.; ...

2016-08-30

X-ray Thomson scattering (XRTS) is a powerful diagnostic for probing warm and hot dense matter. We present the design and results of the first XRTS experiments with hohlraum-driven CH 2 targets on the OMEGA laser. X-rays seen directly from the XRTS x-ray source overshadow the elastic scattering signal from the target capsule, but can be controlled in future experiments. From the inelastic scattering signal, an average plasma temperature is inferred that is in reasonable agreement with the temperatures predicted by simulations. Here, knowledge gained in this experiment show a promising future for further XRTS measurements on indirectly driven OMEGA targets.

X-ray Thomson scattering measurements from hohlraum-driven spheres on the OMEGA laser [X-ray Thomson scattering measurements from hohlraum targets on the OMEGA laser

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

Saunders, A. M.; Jenei, A.; Doppner, T.

X-ray Thomson scattering (XRTS) is a powerful diagnostic for probing warm and hot dense matter. We present the design and results of the first XRTS experiments with hohlraum-driven CH 2 targets on the OMEGA laser. X-rays seen directly from the XRTS x-ray source overshadow the elastic scattering signal from the target capsule, but can be controlled in future experiments. From the inelastic scattering signal, an average plasma temperature is inferred that is in reasonable agreement with the temperatures predicted by simulations. Here, knowledge gained in this experiment show a promising future for further XRTS measurements on indirectly driven OMEGA targets.

Thermal detectors as single photon X-ray spectrometers

NASA Technical Reports Server (NTRS)

Moseley, S. H.; Kelley, R. L.; Mather, J. C.; Mushotzky, R. F.; Szymkowiak, A. E.; Mccammon, D.

1985-01-01

In a thermal detector employed for X-ray spectroscopy applications, the energy of an X-ray is converted to heat in a small mass, and the energy of that X-ray inferred from the size of the temperature rise. The present investigation is concerned with the possibility to make an extremely low heat capacity calorimeter which can be employed as a thermal detector. Several types of calorimeters were fabricated and tested at temperatures as low as approximately 0.05 K. The obtained devices make use of thermistors constructed of melt-doped silicon, nuclear transmutation doped (NTD) germanium, and ion-implanted silicon with a variety of materials for the support and electrical leads. The utility of these microcalorimeters as X-ray spectrometers could be verified.

Dante soft x-ray power diagnostic for National Ignition Facility

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

Dewald, E.L.; Campbell, K.M.; Turner, R.E.

2004-10-01

Soft x-ray power diagnostics are essential for measuring the total x-ray flux, radiation temperature, conversion efficiency, and albedo that define the energetics in indirect and direct drive, as well as other types of high temperature laser plasma experiments. A key diagnostic for absolute radiation flux and radiation temperature in hohlraum experiments is the Dante broadband soft x-ray spectrometer. For the extended range of x-ray fluxes predicted for National Ignition Facility (NIF) compared to Omega or Nova hohlraums, the Dante spectrometer for NIF will include more high energy (<2 keV) edge filter band-pass channels and access to an increased dynamic rangemore » using grids and signal division. This will allow measurements of radiation fluxes of between 0.01 to 100 TW/sr, for hohlraum radiation temperatures between 50 eV and 1 keV. The NIF Dante will include a central four-channel imaging line-of-sight to verify the source size, alignment as well as checking for any radiation contributions from unconverted laser light plasmas.« less

Reactor for tracking catalyst nanoparticles in liquid at high temperature under a high-pressure gas phase with X-ray absorption spectroscopy.

PubMed

Nguyen, Luan; Tao, Franklin Feng

2018-02-01

Structure of catalyst nanoparticles dispersed in liquid phase at high temperature under gas phase of reactant(s) at higher pressure (≥5 bars) is important for fundamental understanding of catalytic reactions performed on these catalyst nanoparticles. Most structural characterizations of a catalyst performing catalysis in liquid at high temperature under gas phase at high pressure were performed in an ex situ condition in terms of characterizations before or after catalysis since, from technical point of view, access to the catalyst nanoparticles during catalysis in liquid phase at high temperature under high pressure reactant gas is challenging. Here we designed a reactor which allows us to perform structural characterization using X-ray absorption spectroscopy including X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy to study catalyst nanoparticles under harsh catalysis conditions in terms of liquid up to 350 °C under gas phase with a pressure up to 50 bars. This reactor remains nanoparticles of a catalyst homogeneously dispersed in liquid during catalysis and X-ray absorption spectroscopy characterization.

Neutron Time-of-Flight Diffractometer HIPPO at LANSCE

NASA Astrophysics Data System (ADS)

Vogel, Sven; Williams, Darrick; Zhao, Yusheng; Bennett, Kristin; von Dreele, Bob; Wenk, Hans-Rudolf

2004-03-01

The High-Pressure Preferred Orientation (HIPPO) neutron diffractometer is the first third-generation neutron time-of-flight powder diffractometer to be constructed in the United States. It produces extremely high intensity by virtue of a short (9 m) initial flight path on a high intensity water moderator and 1380 3He detector tubes covering 4.5 m2 of detector area from 10' to 150' in scattering angles. HIPPO was designed and manufactured as a joint effort between LANSCE and University of California with the goals of attaining world-class science and making neutron powder diffractometry an accessible and available tool to the national user community. Over two decades of momentum transfer are available (0.1-30 A-1) to support studies of amorphous solids; magnetic diffraction; small crystalline samples; and samples subjected to extreme environments such as temperature, pressure, or magnetic fields. The exceptionally high data rates of HIPPO also make it useful for time-resolved studies. In addition to the standard ancillary equipment (100-position sample/texture changer, closed-cycle He refrigerator, furnace), HIPPO has unique high-pressure cells capable of achieving pressures of 30 GPA at ambient and high (2000 K) temperature with samples up to 100 mm3 in volume.

Advanced setup for high-pressure and low-temperature neutron diffraction at hydrostatic conditions

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

Lokshin, Konstantin A.; Zhao Yusheng

2005-06-15

We describe a design of the experimental setup for neutron diffraction studies at low temperatures and hydrostatic pressure. The significant benefit of the setup, compared to the previous methods, is that it makes possible the simultaneous collection of neutrons diffracted at the 30 deg. -150 deg. range with no contamination by the primary scattering from the sample surroundings and without cutting out the incident and diffracted beams. The suggested design is most useful for third-generation time-of-flight diffractometers and constant wavelength instruments. Application of the setup expands the capabilities of high-pressure neutron diffraction, allowing time-resolved kinetics and structural studies, multihistogram Rietveld,more » and pair distribution function and texture analyses. The high efficiency of the setup was proven for the HIPPO diffractometer at Los Alamos Neutron Science Center under pressures up to 10 kbar and temperatures from 4 to 300 K.« less

Synthesis of BaTiO3 and Ba(ZrxTi1-X)O3 by using the soft combustion method

NASA Astrophysics Data System (ADS)

Ahmad, Atiqah; Razak, Khairunisak Abdul

2017-07-01

In this work, barium titanate, BaTiO3 (BT) and Zr doped BT, BaZrxTi1-xO3 (BZT) with powders were successfully produced using the soft combustion method. Barium nitrate and titanium (IV) isopropoxide were used as the starting materials while zirconium (IV) oxynitrate hydrate as the doping precursors, and glycine as the combustion agent. The produced powders were pressed into 12 mm diameter pellets by using 150 MPa cold press. The effect of Zr dopant in BT was studied with molar ratio of x = 0.00, 0.03, 0.05, 0.08 and 0.10. The phase presence was identified using X-ray diffractometer. Morphology of powders and sintered pellets was observed using a scanning electron microscope. Density of the sintered pellets was measured by using Archimedes' principle, while dielectric properties were analysed by using an LCR meter. Pure perovskite BT and BZT structure were obtained after sintering at 1400 °C for 5 h. BZT with x = 0.03 has grain size of 3.9 µm and shows the highest dielectric constant of 525, compared to undoped BT that has the average grain size of 4.2 µm with dielectric constant 223. The results is in agreement with microstructure observation and density of the sample.

Sensitive and Specific Guest Recognition through Pyridinium-Modification in Spindle-Like Coordination Containers.

PubMed

Bhuvaneswari, Nagarajan; Dai, Feng-Rong; Chen, Zhong-Ning

2018-05-02

An elaborately designed pyridinium-functionalized octanuclear zinc(II) coordination container 1-Zn was prepared through the self-assembly of Zn 2+ , p-tert-butylsulfonylcalix[4]arene, and pyridinium-functionalized angular flexible dicarboxylate linker (H 2 BrL1). The structure was determined by a single-crystal X-ray diffractometer. 1-Zn displays highly sensitive and specific recognition to 2-picolylamine as revealed by drastic blueshifts of the absorption and emission spectra, ascribed to the decrease of intramolecular charge transfer (ICT) character of the container and the occurrence of intermolecular charge transfer between the host and guest molecules. The intramolecular charge transfer plays a key role in the modulation of the electronic properties and is tunable through endo-encapsulation of specific guest molecules. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis, Characterization and Comparative Luminescence Studies of Rare-Earth-Doped Gd2O3 Nanoparticles

NASA Astrophysics Data System (ADS)

Pyngrope, D.; Singh, L. R.; Prasad, A. I.; Bora, A.

2018-04-01

A facile direct precipitation method was used for the synthesis of luminescence nanomaterial. Gd2O3 doped with rare earth element Eu3+ is synthesized by polyol route. The synthesized nanoparticles show their characteristic red emission. The nanoparticles are characterized by x-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and photoluminescence (PL) study. The synthesized nanoparticles are spherical particles with 30 nm size. The photoluminescence studies show the characteristic Eu3+ red emission. The PL study shows the intensity of the magnetic dipole transition ( 5 D0 \\to 7 F1 ) at 592 nm compared to that of the electronic dipole transition ( 5 D0 \\to 7 F2 ) at 615 nm. The nanomaterials can show significant application in various display devices and biomedical applications for tracking.

Study on the light-color mixing of rare earth luminescent materials for anti-counterfeiting application

NASA Astrophysics Data System (ADS)

Zhang, Jishu; Zhang, Yingzi; Tao, Jin; Zhu, Yanan

2018-04-01

In order to find out the light color mixing mechanism of rare earth luminescent materials used in anti-counterfeiting fibers, we prepared three kinds of rare earth luminescent materials according to RGB tri-primary color, and mixed it together to form different mixtures in certain proportion. The phase structures of the luminescent material monomers were measured by x-ray diffractometer. The photochromic properties of the luminescent materials were tested and analyzed by fluorescence spectrophotometer. The results show that the light color mixing was consistent with the blending principle of additive color, but not the same because of the photochromic properties of rare earth luminescent materials, and we explored the reasons in the light wavelength and intensity. It was found that the enhancement of the luminescence intensity of the mixture on account of the superimposing of luminescence.

Synthesis of K2O/Zeolite catalysts by KOH impregnation for biodiesel production from waste frying oil

NASA Astrophysics Data System (ADS)

Fitriana, N.; Husin, H.; Yanti, D.; Pontas, K.; Alam, P. N.; Ridho, M.; Iskandar

2018-03-01

K2O/Zeolite compounds were successfully synthesized using KOH as starting material and natural zeolite as support. The catalysts were calcined at 500°C for 3 h and then characterized by X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM). The SEM images reveal that the zeolite and K2O/zeolite particles are irregular in shape (100 to 400 nm). The independent variables were impregnated amounts of KOH (15 - 25%), catalyst to oil ratios of 1.0 - 6.0 wt.%, and reaction time of 2 h. The highest biodiesel yield of 95% was produced from the reaction with 2.1 wt.% catalyst of 25% KOH impregnated. The properties of produced biodiesel complied with SNI. The catalytic stability test showed that the 25% KOH impregnated catalyst was stable.

Significant enhancement in volumetric and gravimetric capacitance of Cu-TiO2/PPY composite for supercapacitor application

NASA Astrophysics Data System (ADS)

Purty, B.; Choudhary, R. B.

2018-04-01

Copper doped titanium dioxide-polypyrrole (Cu-TiO2/PPY) composite was successfully synthesized via chemical oxidative in-situ polymerization process. The structural and morphological properties of Cu-TiO2/PPY composite were investigated using X-ray diffractometer (XRD), field emission electron microscopy (FESEM) and transmission electron microscopy(TEM) techniques. The electrochemical properties of as-synthesized composite were studied using cyclic voltammetry (CV), galvanostatic charge discharge (GCD) and electrochemical impedance spectroscopic (EIS) techniques. The novel Cu-TiO2/PPY composite showed enhanced volumetric capacitance ˜714 F cm-1 and gravimetric capacitance ˜674 F g-1 at 1 A g-1. In addition an excellent coulombic efficiency and comparabley low charge transfer resistance than pure PPY suggests improved supercapacitive performance of Cu-TiO2/PPY composite as an electrode material.

Surface morphological properties of Ag-Al2O3 nanocermet layers using dip-coating technique

NASA Astrophysics Data System (ADS)

Muhammad, Nor Adhila; Suhaimi, Siti Fatimah; Zubir, Zuhana Ahmad; Daud, Sahhidan

2017-12-01

Ag-Al2O3 nanocermet layer was deposited on Cu coated glass substrate using dip-coating technique. The aim of this study was to observe the surface morphology properties of Ag-Al2O3 nanocermet layers after annealing process at 350°C in H2. The surface morphology of Ag-Al2O3 nanocermet will be characterized by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and X-Ray Diffractometer (XRD), respectively. The results show that nearly isolated Ag particles having a large and small size were present in the Al2O3 dielectric matrix after annealing process. The face centered cubic crystalline structure of Ag nanoparticles inclusion in the amorphous alumina dielectric matrix was confirmed using XRD pattern and supported by EDX spectra analysis.

Synthesis and luminescence properties of Sm3+ doped CaTiO3 nanophosphor for application in white LED under NUV excitation.

PubMed

Shivaram, M; Nagabhushana, H; Sharma, S C; Prashantha, S C; Daruka Prasad, B; Dhananjaya, N; Hari Krishna, R; Nagabhushana, B M; Shivakumara, C; Chakradhar, R P S

2014-07-15

CaTiO3:Sm(3+) (1-11 mol%) nanophosphors were successfully synthesized by a low temperature solution combustion method [LCS]. The structural and morphological properties of the phosphors were studied by using Powder X-ray diffractometer (PXRD), Fourier transform infrared (FTIR), X-ray photo electron spectroscopy (XPS), scanning electron microscope (SEM) and transmission electron microscopy (TEM). TEM studies indicate that the size of the phosphor is ∼20-35 nm. Photoluminescence (PL) properties of Sm(3+) (1-11 mol%) doped CaTiO3 for NUV excitation (407 nm) was studied in order to investigate the possibility of its use in White light emitting diode (WLED) applications. The emission spectra consists of intra 4f transitions of Sm(3+), such as (4)G5/2→(6)H5/2 (561 nm), (4)G5/2→(6)H7/2 (601-611 nm), (4)G5/2→(6)H9/2 (648 nm) and (4)G5/2→(6)H11/2 (703 nm) respectively. Further, the emission at 601-611 nm show strong orange-red emission and can be applied to the orange-red emission of phosphor for the application for near ultra violet (NUV) excitation. Thermoluminescence (TL) of the samples irradiated with gamma source in the dose range 100-500 Gy was recorded at a heating rate of 5°Cs(-1). Two well resolved glow peaks at 164°C and 214°C along with shouldered peak at 186°C were recorded. TL intensity increases up to 300 Gy and thereafter, it decreases with further increase of dose. The kinetic parameters namely activation energy (E), frequency factor (s) and order of kinetics were estimated and results were discussed in detail. Copyright © 2014 Elsevier B.V. All rights reserved.

A furnace with rotating load frame for in situ high temperature deformation and creep experiments in a neutron diffraction beam line

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

Reiche, H. M.; New Mexico State University, Las Cruces, New Mexico 88003; Vogel, S. C.

2012-05-15

A resistive furnace combined with a load frame was built that allows for in situ neutron diffraction studies of high temperature deformation, in particular, creep. A maximum force of 2700 N can be applied at temperatures up to 1000 deg. C. A load control mode permits studies of, e.g., creep or phase transformations under applied uni-axial stress. In position control, a range of high temperature deformation experiments can be achieved. The examined specimen can be rotated up to 80 deg. around the vertical compression axis allowing texture measurements in the neutron time-of-flight diffractometer HIPPO (High Pressure - Preferred Orientation). Wemore » present results from the successful commissioning, deforming a Zr-2.5 wt.% Nb cylinder at 975 deg. C. The device is now available for the user program of the HIPPO diffractometer at the LANSCE (Los Alamos Neutron Science Center) user facility.« less

Big Bangs in Galaxy Clusters: Using X-ray Temperature Maps to Trace Merger Histories in Clusters with Radio Halos/Relics

NASA Astrophysics Data System (ADS)

Burns, Jack O.; Datta, Abhirup; Hallman, Eric J.

2016-06-01

Galaxy clusters are assembled through large and small mergers which are the most energetic events ("bangs") since the Big Bang. Cluster mergers "stir" the intracluster medium (ICM) creating shocks and turbulence which are illuminated by ~Mpc-sized radio features called relics and halos. These shocks heat the ICM and are detected in x-rays via thermal emission. Disturbed morphologies in x-ray surface brightness and temperatures are direct evidence for cluster mergers. In the radio, relics (in the outskirts of the clusters) and halos (located near the cluster core) are also clear signposts of recent mergers. Our recent ENZO cosmological simulations suggest that around a merger event, radio emission peaks very sharply (and briefly) while the x-ray emission rises and decays slowly. Hence, a sample of galaxy clusters that shows both luminous x-ray emission and radio relics/halos are good candidates for very recent mergers. We are in the early stages of analyzing a unique sample of 48 galaxy clusters with (i) known radio relics and/or halos and (ii) significant archival x-ray observations (>50 ksec) from Chandra and/or XMM. We have developed a new x-ray data analysis pipeline, implemented on parallel processor supercomputers, to create x-ray surface brightness, high fidelity temperature, and pressure maps of these clusters in order to study merging activity. The temperature maps are made using three different map-making techniques: Weighted Voronoi Tessellation, Adaptive Circular Binning, and Contour Binning. In this talk, we will show preliminary results for several clusters, including Abell 2744 and the Bullet cluster. This work is supported by NASA ADAP grant NNX15AE17G.

Beam Heating of Samples: Modeling and Verification. Part 2

NASA Technical Reports Server (NTRS)

Kazmierczak, Michael; Gopalakrishnan, Pradeep; Kumar, Raghav; Banerjee Rupak; Snell, Edward; Bellamy, Henry; Rosenbaum, Gerd; vanderWoerd, Mark

2006-01-01

Energy absorbed from the X-ray beam by the sample requires cooling by forced convection (i.e. cryostream) to minimize temperature increase and the damage caused to the sample by the X-ray heating. In this presentation we will first review the current theoretical models and recent studies in the literature, which predict the sample temperature rise for a given set of beam parameters. It should be noted that a common weakness of these previous studies is that none of them provide actual experimental confirmation. This situation is now remedied in our investigation where the problem of x-ray sample heating is taken up once more. We have theoretically investigated, and at the same time, in addition to the numerical computations, performed experiments to validate the predictions. We have modeled, analyzed and experimentally tested the temperature rise of a 1 mm diameter glass sphere (sample surrogate) exposed to an intense synchrotron X-ray beam, while it is being cooled in a uniform flow of nitrogen gas. The heat transfer, including external convection and internal heat conduction was theoretically modeled using CFD to predict the temperature variation in the sphere during cooling and while it was subjected to an undulator (ID sector 19) X-ray beam at the APS. The surface temperature of the sphere during the X-ray beam heating was measured using the infrared camera measurement technique described in a previous talk. The temperatures from the numerical predictions and experimental measurements are compared and discussed. Additional results are reported for the two different sphere sizes and for two different supporting pin orientations.

Anisotropic pyrochemical microetching of poly(tetrafluoroethylene) initiated by synchrotron radiation-induced scission of molecule bonds

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

Yamaguchi, Akinobu, E-mail: yamaguti@lasti.u-hyogo.ac.jp, E-mail: utsumi@lasti.u-hyogo.ac.jp; Kido, Hideki; Utsumi, Yuichi, E-mail: yamaguti@lasti.u-hyogo.ac.jp, E-mail: utsumi@lasti.u-hyogo.ac.jp

2016-02-01

We developed a process for micromachining polytetrafluoroethylene (PTFE): anisotropic pyrochemical microetching induced by synchrotron X-ray irradiation. X-ray irradiation was performed at room temperature. Upon heating, the irradiated PTFE substrates exhibited high-precision features. Both the X-ray diffraction peak and Raman signal from the irradiated areas of the substrate decreased with increasing irradiation dose. The etching mechanism is speculated as follows: X-ray irradiation caused chain scission, which decreased the number-average degree of polymerization. The melting temperature of irradiated PTFE decreased as the polymer chain length decreased, enabling the treated regions to melt at a lower temperature. The anisotropic pyrochemical etching process enabledmore » the fabrication of PTFE microstructures with higher precision than simultaneously heating and irradiating the sample.« less

Structural Stability of Diffusion Barriers in Cu/Ru/MgO/Ta/Si

PubMed Central

Hsieh, Shu-Huei; Chen, Wen Jauh; Chien, Chu-Mo

2015-01-01

Various structures of Cu (50 nm)/Ru (2 nm)/MgO (0.5–3 nm)/Ta (2 nm)/Si were prepared by sputtering and electroplating techniques, in which the ultra-thin trilayer of Ru (2 nm)/MgO (0.5–3 nm)/Ta (2 nm) is used as the diffusion barrier against the interdiffusion between Cu film and Si substrate. The various structures of Cu/Ru/MgO/Ta/Si were characterized by four-point probes for their sheet resistances, by X-ray diffractometers for their crystal structures, by scanning electron microscopes for their surface morphologies, and by transmission electron microscopes for their cross-section and high resolution views. The results showed that the ultra-thin tri-layer of Ru (2 nm)/MgO (0.5–3 nm)/Ta (2 nm) is an effective diffusion barrier against the interdiffusion between Cu film and Si substrate. The MgO, and Ta layers as deposited are amorphous. The mechanism for the failure of the diffusion barrier is that the Ru layer first became discontinuous at a high temperature and the Ta layer sequentially become discontinuous at a higher temperature, the Cu atoms then diffuse through the MgO layer and to the substrate at the discontinuities, and the Cu3Si phases finally form. The maximum temperature at which the structures of Cu (50 nm)/Ru (2 nm)/MgO (0.5–3 nm)/Ta (2 nm)/Si are annealed and still have low sheet resistance is from 550 to 750 °C for the annealing time of 5 min and from 500 to 700 °C for the annealing time of 30 min. PMID:28347099

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

Balman, Şölen; Godon, Patrick; Sion, Edward M., E-mail: solen@astroa.physics.metu.edu.tr, E-mail: patrick.godon@villanova.edu, E-mail: edward.sion@villanova.edu

We present a total of ∼45 ks (3 × 15 ks) of Swift X-Ray Telescope (XRT) observations for three nonmagnetic nova-like (NL) cataclysmic variables (CVs; MV Lyr, BZ Cam, V592 Cas) in order to study characteristics of boundary layers (BLs) in CVs. The nonmagnetic NLs are found mostly in a state of high mass accretion rate (≥1 × 10{sup –9} M {sub ☉} yr{sup –1}), and some show occasional low states. Using the XRT data, we find optically thin multiple-temperature cooling flow type emission spectra with X-ray temperatures (kT {sub max}) of 21-50 keV. These hard X-ray-emitting BLs diverge frommore » simple isobaric cooling flows, indicating X-ray temperatures that are of virial values in the disk. In addition, we detect power-law emission components from MV Lyr and BZ Cam and plausibly from V592 Cas, which may be a result of the Compton scattering of the optically thin emission from the fast wind outflows in these systems and/or Compton upscattering of the soft disk photons. The X-ray luminosities of the (multitemperature) thermal plasma emission in the 0.1-50.0 keV range are (0.9-5.0) × 10{sup 32} erg s{sup –1}. The ratio of the X-ray and disk luminosities (calculated from the UV-optical wavelengths) yields an efficiency (L{sub x} /L {sub disk}) ∼ 0.01-0.001. Given this non-radiative ratio for the X-ray-emitting BLs with no significant optically thick blackbody emission in the soft X-rays (consistent with ROSAT observations), together with the high/virial X-ray temperatures, we suggest that high-state NL systems may have optically thin BLs merged with ADAF-like flows and/or X-ray coronae. In addition, we note that the axisymmetric bipolar and/or rotation-dominated fast-wind outflows detected in these three NLs (particularly BZ Cam and V592 Cas) or some other NL may also be explained in the context of ADAF-like BL regions.« less

Dante Soft X-ray Power Diagnostic for NIF

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

Dewald, E; Campbell, K; Turner, R

2004-04-15

Soft x-ray power diagnostics are essential for measuring spectrally resolved the total x-ray flux, radiation temperature, conversion efficiency and albedo that are important quantities for the energetics of indirect drive hohlraums. At the Nova or Omega Laser Facilities, these measurements are performed mainly with Dante, but also with DMX and photo-conductive detectors (PCD's). The Dante broadband spectrometer is a collection of absolute calibrated vacuum x-ray diodes, thin filters and x-ray mirrors used to measure the soft x-ray emission for photon energies above 50 eV.

Study of microdefects and their distribution in dislocation-free Si-doped HB GaAs by X-ray diffuse scattering on triple-crystal diffractometer

NASA Astrophysics Data System (ADS)

Charniy, L. A.; Morozov, A. N.; Bublik, V. T.; Scherbachev, K. D.; Stepantsova, I. V.; Kaganer, V. M.

1992-03-01

Microdefects in dislocation-free Si-doped (n = (1-3) × 10 18cm-3) HB GaAs crystals were studied by X-ray diffuse scattering measured with the help of a triple-crystal diffractometer. The intensity of the diffuse scattering as well as the isointensity contours around different reciprocal lattice points were analysed. A comparison of the measured isointensity contours with the theoretically calculated ones showed that the microdefects detected are interstitial dislocation loops with the Burgers vectors b = {1}/{2}<110 #3862;; lying in the planes #38;{110} and {111}. The mean radius of the dislocation loops R0 was determined using the wave vector q0 alpha; R-10 corresponding to the transmition point where the Huang diffuse scattering I( q) alpha q-2 ( q < q0) changed to the asymptotic scattering I( q) alpha q-4 ( q #62 q0). The analysis of a D-shaped cross-sectional (111) wafer cut from the end part of the HB ingot showed that R0 changed smoothly along the [ overline211] symmetry axis of the wafer. The highly inhomogeneous "new-moon"-like distribution of the non-dislocational etch-pits was also obtained. The maximal loop radius obtained at the edges of the wafer, R 0 = 1 μm, corresponds to the wafer area enriched with etch-pits and the minimal one, R 0 = 0.3 μm, corresponds to the bound of the new-moon-like area denuded from etch-pits. Microdefects of a new type were detected in the denuded area. These microdefects consist of nuclei, 0.1 μm in radius, and an extended atmosphere of interstitials. The minimal microdefect radius in the centre of the wafer corresponds to the maximum local value of the lattice parameter a = 5.655380 Å, and the minimum local value a = 5.65372 Å was obtained at the wafer edges enriched with microdefect-related etch-pits. Absolute X-ray diffuse intensity measurements were used for microdefect concentration determination. Normalization of I( q) was based on the comparison of the Huang intensity with the thermal diffuse scattering intensity which is predominant for the wave vector q å R-10. The microdefect concentration determined in this way appeared to be 4 × 10 9 cm -3 at the edges of the wafer and 4 × 10 11 cm -3 at the centre of the new-moon-like etch-pit denuded zone. The number of interstitial atoms forming dislocation loops is shown to be the same across the area of the wafer and equal to 10 16 cm -3.

5.8 X-ray Calorimeters

NASA Technical Reports Server (NTRS)

Porter, F. Scott

2008-01-01

X-ray calorimeter instruments for astrophysics have seen rapid development since they were invented in 1984. The prime instrument on all currently planned X-ray spectroscopic observatories is based on calorimeter technology. This relatively simple detection concept that senses the energy of an incident photon by measuring the temperature rise of an absorber material at very low temperatures, can form the basis of a very high performance, non-dispersive spectrometer. State-of-the-art calorimeter instruments have resolving powers of over 3000, large simultaneous band-passes, and near unit efficiency. This coupled with the intrinsic imaging capability of a pixilated x-ray calorimeter array, allows true spectral-spatial instruments to be constructed. In this chapter I briefly review the detection scheme, the state-of-the-art in X-ray calorimeter instruments and the future outlook for this technology.

X-RAY EMISSION FROM MAGNETIC MASSIVE STARS

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

Nazé, Yaël; Petit, Véronique; Rinbrand, Melanie

2014-11-01

Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ∼60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- M-dot B stars and flattens formore » the more luminous, higher- M-dot O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres.« less

Automated analysis of hot spot X-ray images at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Khan, S. F.; Izumi, N.; Glenn, S.; Tommasini, R.; Benedetti, L. R.; Ma, T.; Pak, A.; Kyrala, G. A.; Springer, P.; Bradley, D. K.; Town, R. P. J.

2016-11-01

At the National Ignition Facility, the symmetry of the hot spot of imploding capsules is diagnosed by imaging the emitted x-rays using gated cameras and image plates. The symmetry of an implosion is an important factor in the yield generated from the resulting fusion process. The x-ray images are analyzed by decomposing the image intensity contours into Fourier and Legendre modes. This paper focuses on the additional protocols for the time-integrated shape analysis from image plates. For implosions with temperatures above ˜4 keV, the hard x-ray background can be utilized to infer the temperature of the hot spot.

Automated analysis of hot spot X-ray images at the National Ignition Facility

DOE PAGES

Khan, S. F.; Izumi, N.; Glenn, S.; ...

2016-09-02

At the National Ignition Facility, the symmetry of the hot spot of imploding capsules is diagnosed by imaging the emitted x-rays using gated cameras and image plates. The symmetry of an implosion is an important factor in the yield generated from the resulting fusion process. The x-ray images are analyzed by decomposing the image intensity contours into Fourier and Legendre modes. This paper focuses on the additional protocols for the time-integrated shape analysis from image plates. Here, for implosions with temperatures above ~4keV, the hard x-ray background can be utilized to infer the temperature of the hot spot.

Dimension dependent immunity of X-ray irradiation on low-temperature polycrystalline-silicon TFTs

NASA Astrophysics Data System (ADS)

Wei, Yin-Chang; Li, Yi-Chieh; Lee, I.-Che; Cheng, Huang-Chung

2017-06-01

Typically, each element in a large-area flat-panel X-ray image sensor consists of a photodetector and amorphous silicon (a-Si) thin-film transistor (TFT) switches. In order to reduce noise, increase sensor dynamic range, and increase carrying capacity, the low-temperature polycrystalline-silicon (LTPS) TFTs have been proposed as a candidate to replace the a-Si TFTs. However, there are concerns regarding the impact of X-ray radiation in LTPS-TFTs, and several studies have been conducted to inquire into the same. In this paper, we show that LTPS TFTs with small channel length (<2 µm) are almost immune to X-ray radiation.

Automated analysis of hot spot X-ray images at the National Ignition Facility

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

Khan, S. F., E-mail: khan9@llnl.gov; Izumi, N.; Glenn, S.

At the National Ignition Facility, the symmetry of the hot spot of imploding capsules is diagnosed by imaging the emitted x-rays using gated cameras and image plates. The symmetry of an implosion is an important factor in the yield generated from the resulting fusion process. The x-ray images are analyzed by decomposing the image intensity contours into Fourier and Legendre modes. This paper focuses on the additional protocols for the time-integrated shape analysis from image plates. For implosions with temperatures above ∼4 keV, the hard x-ray background can be utilized to infer the temperature of the hot spot.

Automated analysis of hot spot X-ray images at the National Ignition Facility.

PubMed

Khan, S F; Izumi, N; Glenn, S; Tommasini, R; Benedetti, L R; Ma, T; Pak, A; Kyrala, G A; Springer, P; Bradley, D K; Town, R P J

2016-11-01

At the National Ignition Facility, the symmetry of the hot spot of imploding capsules is diagnosed by imaging the emitted x-rays using gated cameras and image plates. The symmetry of an implosion is an important factor in the yield generated from the resulting fusion process. The x-ray images are analyzed by decomposing the image intensity contours into Fourier and Legendre modes. This paper focuses on the additional protocols for the time-integrated shape analysis from image plates. For implosions with temperatures above ∼4 keV, the hard x-ray background can be utilized to infer the temperature of the hot spot.

X-ray imaging for studying behavior of liquids at high pressures and high temperatures using Paris-Edinburgh press

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

Kono, Yoshio; Kenney-Benson, Curtis; Park, Changyong

2015-07-15

Several X-ray techniques for studying structure, elastic properties, viscosity, and immiscibility of liquids at high pressures have been integrated using a Paris-Edinburgh press at the 16-BM-B beamline of the Advanced Photon Source. Here, we report the development of X-ray imaging techniques suitable for studying behavior of liquids at high pressures and high temperatures. White X-ray radiography allows for imaging phase separation and immiscibility of melts at high pressures, identified not only by density contrast but also by phase contrast imaging in particular for low density contrast liquids such as silicate and carbonate melts. In addition, ultrafast X-ray imaging, at framemore » rates up to ∼10{sup 5} frames/second (fps) in air and up to ∼10{sup 4} fps in Paris-Edinburgh press, enables us to investigate dynamics of liquids at high pressures. Very low viscosities of melts similar to that of water can be reliably measured. These high-pressure X-ray imaging techniques provide useful tools for understanding behavior of liquids or melts at high pressures and high temperatures.« less

The Amorphous Composition of Three Mudstone Samples from Gale Crater: Implications for Weathering and Diagenetic Processes on Mars

NASA Technical Reports Server (NTRS)

Achilles, C. N.; Downs, R. T.; Rampe, E. B.; Morris, R. V.; Bristow, T. F.; Ming, D. W.; Blake, D. F.; Vaniman, D. T.; Morrison, S. M.; Sutter, B.;

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

Ghammraoui, B; M Popescu, L; Badano, A

Purpose: To investigate the ability of Coherent Scatter Computed Tomography (CSCT) to distinguish non-invasively between type I calcifications, consisting of calcium oxalate dihydrate (CO) compounds which are more often associated with benign lesions, and type II calcifications containing hydroxyapatite (HA) which are predominantly associated with malignant tumors. Methods: The coherent scatter cross sections of HA and CO were measured using an energy dispersive x-ray diffractometer. The measured cross sections were introduced into MC-GPU Monte Carlo simulation code for studying the applicability of CSCT to discriminate between the two types of microcalcifications within the whole breast. Simulations were performed on amore » virtual phantom with inserted HA and CO spots of different sizes and placed in regions of interest having different background compositions. We considered a polychromatic x-ray source and an energy resolving photon counting detector. We applied an algorithm that estimates scatter components in projection space in order to obtain material-specific images of the breast. As material components adipose, glandular, HA and CO were used. The relative contrast of HA and CO components were used for type I and type II microcalcification discrimination. Results: The reconstructed CSCT images showed material-specific component-contrast values, with the highest CO or HA component contrast corresponding generally to the actual CO or HA feature, respectively. The discrimination performance varies with the x-ray intensity, calcification size, and background composition. The results were summarized using receiver operating characteristic (ROC) analysis with the area under the curve (AUC) taken as an overall indicator of discrimination performance and showing high AUC values up to unity. Conclusion: The simulation results obtained for a uniform breast imaging phantom indicate that CSCT has potential to be used as a non-invasive method for discrimination between type I and type II microcalcifications.« less

Quantitative analysis on orientation of human bone integrated with midpalatal implant by micro X-ray diffractometer

NASA Astrophysics Data System (ADS)

Murata, Masaru; Akazawa, Toshiyuki; Yuasa, Toshihiro; Okayama, Miki; Tazaki, Junichi; Hanawa, Takao; Arisue, Makoto; Mizoguchi, Itaru

2012-12-01

A midpalatal implant system has been used as the unmoved anchorage for teeth movement. An 18-year-old male patient presented with reversed occlusion and was diagnosed as malocclusion. A pure titanium fixture (lengths: 4 mm, diameter: 3.3 mm, Orthosystem®, Institute Straumann, Switzerland) was implanted into the palatal bone of the patient as the orthodontic anchorage. The implant anchorage was connected with the upper left and right first molars, and had been used for 3 years. After dynamic treatments, the titanium fixture connected with bone was removed surgically, fixed in formalin solution, and embedded in resin. Specimens were cut along the frontal section of face and the direction of longitudinal axis of the implant, stained, and observed histologically. The titanium fixture was integrated directly with compact bone showing cortical bone-like structure such as lamella and osteon. In addition, to qualitatively characterize the implant-supported human bone, the crystallinity and orientation of hydroxyapatite (HAp) phase were evaluated by the microbeam X-ray diffraction analysis. Preferential alignment of c-axis of HAp crystals was represented by the relative intensity ratio of (0 0 2)-face diffraction peak to (3 1 0)-face one. The values decreased monotonously along the direction of the lateral stress from the site near the implant thread to the distant site in all horizontal lines of the map. These results indicated that the X-ray images for the intensity of c-face in HAp revealed functionally graded distribution of cortical bone quality. The micro-scale measurements of HAp structure could be a useful method for evaluating the mechanical stress distribution in human hard tissues.

Anisotropic crystal deformation measurements determined using powder X-ray diffraction and a new in situ compression stage.

PubMed

Haware, Rahul V; Kim, Paul; Ruffino, Lauren; Nimi, Brian; Fadrowsky, Catherine; Doyle, Michael; Boerrigter, Stephan X M; Cuitino, Alberto; Morris, Ken

2011-10-14

This report addresses the development of experimental and computational estimations of the anisotropic elastic moduli (EM) of single crystals to aid in the a priori (i.e., starting with the crystal structure) prediction of the trend as a function of the direction of applied stress. Experimentally EM values in the normal direction to the X-, Y- and Z-planes of block shaped aspirin and acetaminophen crystals were determined using data generated by the newly designed compression stage housed in our powder X-ray diffractometer. Computational estimations of EM were made using the applicable modules in Material Studio 5.5. The measured EM values normal to the (100), (020) and (002) planes of aspirin, and (20-1), (020) and (001) planes of acetaminophen crystals by both methods succeeded in detected the anisotropic behavior. However, disparity in the relative values between measured EM values by different techniques was observed. This may be attributed to deformation sources other than lattice compression including inelastic processes such as local failure and plasticity as well as deformation at the crystal-probe interfaces due to crystal surface roughness (asperities). The trend of the ratio of the values from the respective methods showed reasonable agreement and promise for the technique. The present approach demonstrated the suitability of the compression stage to determine and predict anisotropic EM of subjected small molecular organic crystals. Copyright © 2011 Elsevier B.V. All rights reserved.

Spectral and Timing Investigations of Dwarf Novae Selected in Hard X-Rays

NASA Technical Reports Server (NTRS)

Thorstensen, John; Remillard, Ronald A.

2000-01-01

There are 9 dwarf novae (DN) among the 43 cataclysmic variables (accreting white dwarfs in close binary systems) that were detected during the HEAO-1 all-sky X-ray survey (1977-1979). On the other hand, there are roughly one hundred dwarf novae that are closer and/or optically brighter and yet they were not detected as hard X-ray sources. Two of the HEAO-1 DN show evidence for X-ray pulsations that imply strong magnetic fields on the white dwarf surface, and magnetic CVs are known to be strong X-ray sources. However, substantial flux in hard X-rays may be caused by non-magnetic effects, such as an optically thin boundary layer near a massive white dwarf. We proposed RXTE observations to measure plasma temperatures and to search for X-ray pulsations. The observations would distinguish whether these DN belong to one of (rare) magnetic subclasses. For those that do not show pulsations, the observations support efforts to define empirical relations between X-ray temperature, the accretion rate, and the mass of the white dwarf. The latter is determined via optical studies of the dynamics of the binary constituents.

Discovery of X-Ray Emission from the Galactic Supernova Remnant G32.8-0.1 with Suzaku

NASA Astrophysics Data System (ADS)

Bamba, Aya; Terada, Yukikatsu; Hewitt, John; Petre, Robert; Angelini, Lorella; Safi-Harb, Samar; Zhou, Ping; Bocchino, Fabrizio; Sawada, Makoto

2016-02-01

We present the first dedicated X-ray study of the supernova remnant (SNR) G32.8-0.1 (Kes 78) with Suzaku. X-ray emission from the whole SNR shell has been detected for the first time. The X-ray morphology is well correlated with the emission from the radio shell, while anti-correlated with the molecular cloud found in the SNR field. The X-ray spectrum shows not only conventional low-temperature (kT ˜ 0.6 keV) thermal emission in a non-equilibrium ionization state, but also a very high-temperature (kT ˜ 3.4 keV) component with a very low ionization timescale (˜2.7 × 109 cm-3 s), or a hard nonthermal component with a photon index Γ ˜ 2.3. The average density of the low-temperature plasma is rather low, of the order of 10-3-10-2 cm-3, implying that this SNR is expanding into a low-density cavity. We discuss the X-ray emission of the SNR, also detected in TeV with H.E.S.S., together with multi-wavelength studies of the remnant and other gamma-ray emitting SNRs, such as W28 and RCW 86. Analysis of a time-variable source, 2XMM J185114.3-000004, found in the northern part of the SNR, is also reported for the first time. Rapid time variability and a heavily absorbed hard-X-ray spectrum suggest that this source could be a new supergiant fast X-ray transient.

Discovery of X-Ray Emission from the Galactic Supernova Remnant G32.8-0.1 with Suzaku

NASA Technical Reports Server (NTRS)

Bamba, Aya; Terada, Yukikatsu; Hewitt, John; Petre, Robert; Angelini, Lorella; Safi-Harb, Samar; Zhou, Ping; Bocchino, Fabrizio; Sawada, Makoto

2016-01-01

We present the first dedicated X-ray study of the supernova remnant (SNR) G32.8-0.1 (Kes 78) with Suzaku. X-ray emission from the whole SNR shell has been detected for the first time. The X-ray morphology is well correlated with the emission from the radio shell, while anti-correlated with the molecular cloud found in the SNR field. The X-ray spectrum shows not only conventional low-temperature (kT approximately 0.6 kiloelectronvolts) thermal emission in a nonequilibrium ionization state, but also a very high-temperature (approximately 3.4 kiloelectronvolts) component with a very low ionization timescale (approximately 2.7 times 10 (sup 9) per cubic centimeter per second), or a hard nonthermal component with a photon index Gamma approximately equal to 2.3. The average density of the low-temperature plasma is rather low, of the order of 10 (sup -3) - 10 (sup -2) per cubic centimeter, implying that this SNR is expanding into a low-density cavity. We discuss the X-ray emission of the SNR, also detected in teraelectronvolts with H.E.S.S. (High Energy Stereoscopic System), together with multi-wavelength studies of the remnant and other gamma-ray emitting SNRs, such as W28 and RCW 86. Analysis of a time-variable source, 2XMM J185114.3-000004, found in the northern part of the SNR, is also reported for the first time. Rapid time variability and a heavily absorbed hard-X-ray spectrum suggest that this source could be a new supergiant fast X-ray transient.

Infrared and X-Ray Spectroscopy of the KES 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties

NASA Technical Reports Server (NTRS)

Temim, Tea; Dwek, Eli; Slane, Patrick; Arendt, Richard G.

2009-01-01

We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of 1.5 keV, or with two thermal components with temperatures of 1.5 and 0.2 keV. Previous studies suggest that the hot component may originate from reverse-shocked SN ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from supernova (SN) ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and ill emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of 140 K by a relatively dense, hot plasma, that also gives rise to the hot X-ray emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-ray emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) solar mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative estimates of density and filling factors of the clumpy medium swept up by the SNR.

Infrared and X-Ray Spectroscopy of the Kes 75 Supernova Shell Characterizing the Dust and Gas Properties

NASA Technical Reports Server (NTRS)

Temim, Tea; Arendt, Richard G.; Dwek, Eli; Slane, Patrick

2012-01-01

We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of approx 1.5 keV, or with two thermal components with temperatures of 1.5 and 0.2 keY. Previous studies suggest that the hot component may originate from reverse-shocked SN ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from supernova (SN) ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and IR emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of approx 140 K by a relatively dense, hot plasma, that also gives rise to the hot X-ray emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-ray emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) Solar Mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative estimates of density and filling factors of the clumpy medium swept up by the SNR.

Temperature dependence of a superconducting tunnel junction x-ray detector

NASA Astrophysics Data System (ADS)

Hiller, Lawrence J.; Labov, Simon E.; Mears, Carl A.; Barfknecht, Andrew T.; Frank, Matthias A.; Netel, Harrie; Lindeman, Mark A.

1995-09-01

Superconducting tunnel junctions can be used as part of a high-resolution, energy-dispersive x- ray detector. The energy of the absorbed x ray is used to break superconducting electron pairs, producing on the order of 10(superscript 6) excitations, called quasiparticles. The number of quasiparticles produced is proportional to the energy of the absorbed x ray. When a bias voltage is maintained across the barrier, these quasiparticles produce a net tunneling current. Either the peak tunneling current or the total tunneled charge may be measured to determine the energy of the absorbed x ray. The tunneling rate, and therefore the signal, is enhanced by the use of a quasiparticle trap near the tunnel barrier. The trapping efficiency is improved by decreasing the energy gap, though this reduces the maximum temperature at which the device may operate. In our niobium/aluminum configuration, we can very the energy gap in the trapping layer by varying its thickness. This paper examines the performance of two devices with 50 nm aluminum traps at temperatures ranging from 100 mK to 700 mK. We found that this device has a very good energy resolution of about 12 eV FWHM at 1 keV. This energy resolution is independent of temperature for much of this temperature range.

X-ray emission from high temperature plasmas

NASA Technical Reports Server (NTRS)

Harries, W. L.

1976-01-01

The physical processes occurring in plasma focus devices were studied. These devices produce dense high temperature plasmas, which emit X rays of hundreds of KeV energy and one to ten billion neutrons per pulse. The processes in the devices seem related to solar flare phenomena, and would also be of interest for controlled thermonuclear fusion applications. The high intensity, short duration bursts of X rays and neutrons could also possibly be used for pumping nuclear lasers.

The Biggest Bangs Since the Big Bang: Unveiling Mergers of Galaxy Clusters with Radio Halos/Relics Using X-ray Temperature Maps

NASA Astrophysics Data System (ADS)

Burns, Jack

Galaxy clusters are assembled through large and small mergers which are the most energetic events ( bangs ) since the Big Bang. Cluster mergers stir the ICM creating shocks and turbulence which are illuminated by Mpc-sized radio features called relics and halos. These shocks heat the ICM and are detected in x-rays via thermal emission. Disturbed morphologies in x-ray surface brightness and temperatures are direct evidence for cluster mergers. In the radio, relics (in the outskirts of the clusters) and halos (located near the cluster core) are clear signposts of recent mergers. Our recent cosmological simulations suggest that around a merger event, radio emission peaks very sharply (and briefly) while the x-ray emission rises and decays slowly. Hence, a sample of galaxy clusters that shows both luminous x-ray and radio relics/halos are clear candidates for very recent mergers. We propose to analyze a unique sample of 48 galaxy clusters with (i) known radio relics and/or halos and (ii) significant archival x-ray observations (e 50 ksec) from Chandra and/or XMM. We will use a new x-ray data analysis pipeline, implemented on a parallelprocessor supercomputer, to create x-ray surface brightness, high fidelity temperature, and pressure maps of these clusters in order to study merging activity. In addition, we will use a control sample of clusters from the HIFLUGCS catalog which do not show radio relics/halos or any significant x-ray surface brightness substructure, thus devoid of recent mergers. The temperature maps will be made using 3 different map-making techniques: Weighted Voronoi Tessellation, Adaptive Circular Binning, and Contour Binning. We also plan to use archival Suzaku data for 22 clusters in our sample and study the x-ray temperatures at the outskirts of the clusters. All 48 clusters have archival radio data at d1.4 GHz which will be re-analyzed using advanced algorithms in NRAO s CASA software. We also have new radio data on a subset of these clusters and have proposed to observe more of them with the increased sensitivity of the JVLA and GMRT at 0.25-1.4 GHz. Using the systematically analyzed x-ray and radio data, we propose to pursue the detailed link between cluster mergers and the formation of radio relics/halos. (a) How do radio relics form? Radio relics are believed to be created via re-acceleration of cosmic ray electrons through diffusive shock acceleration, a 1st order Fermi mechanism. Hence, there should be a correlation between shocks detected in the x-ray and radio. We plan to use our newly developed 2-D shock-finder using jumps within xray temperature maps, and complement the results with radio Mach numbers derived from radio spectral indices. Shocks detected in our simulations using a 3-D shock-finder will be used to understand the effects of projections in observations. (b) How do radio halos form? It is not clear if the formation of radio halos is due to turbulent acceleration (2nd order Fermi process) or due to more efficient 1st order Fermi mechanism via distributed small-scale shocks. Since radio halos reside in merging clusters, the x-ray temperature structure should show the un-relaxed nature of the cluster. We will study this through temperature asymmetry and power ratios (between two multipoles). We also propose to use pressure maps to derive a 2-D power spectrum of pressure fluctuations and deduce the turbulent velocity field. We will then derive the associated radio power and spectral indices to compare with the radio observations. We will test our results using clusters with and without radio halos. We will make these high fidelity temperature, surface brightness, pressure and entropy maps available to the astronomical community via the National Virtual Observatory. We will also make our x-ray temperature map-making scripts implemented on parallel supercomputers available for community use.

Ionic charge distributions of energetic particles from solar flares

NASA Technical Reports Server (NTRS)

Mullan, D. J.; Waldron, W. L.

1986-01-01

The effects which solar flare X-rays have on the charge states of solar cosmic rays is determined quantitatively. Rather than to characterize the charge distribution by temperature alone, it is proposed that the X-ray flux at the acceleration site also is used. The effects of flare X-rays are modeled mathematically.

Curiosity Rover's CheMin Instrument Investigates Mineralogy of Gale Crater and Implications for Diagenesis

NASA Astrophysics Data System (ADS)

Fendrich, Kim; Rampe, Elizabeth; Vaniman, David; Bish, David; Blake, David; Treiman, Allan; Ming, Doug; Morris, Richard; Bristow, Tom; Cavanagh, Patrick; Downs, Robert; Morrison, Shaunna; Chipera, Steve; Achilles, Cherie; Farmer, Jack; Sarrazin, Philippe; Crisp, Joy; Morookian, John Michael; Yen, Albert; Gellert, Ralf

2015-04-01

The Mars Science Laboratory rover Curiosity employs a suite of instruments to investigate past or present habitability of Mars, as observed at Gale crater and particularly in the lower strata of the crater's central mound, informally named Mount Sharp. The X-ray diffractometer on board, CheMin, is used to assess the quantitative mineralogy of scooped soil samples and drilled rock powders. Methods of modeling diffraction peak positions and intensities to evaluate the abundances of minerals include Rietveld refinement and FULLPAT (full-pattern fitting). Each of the samples analyzed by CheMin contains X-ray amorphous material. The amorphous component chemistry is resolved by subtracting the chemistry of the crystalline composition, as determined by X-ray diffraction data, from the bulk sample chemistry, as determined by the Alpha Particle X-ray Spectrometer (APXS). Diffraction results have been obtained on five samples thus far to include Rocknest, John Klein, Cumberland, Windjana and Confidence Hills. Soil samples collected at Rocknest, an aeolian bedform in Gale crater, were the first to be analyzed in situ by CheMin. The Rocknest mineral assemblage is basaltic (plagioclase, Fe-forsterite, augite, pigeonite) and contains amorphous material that is compositionally similar to palagonitic volcanic soils found on Earth, with the addition of sulfur and chlorine. The four drill analyses are characteristic of deposition in a variety of fluvio-lacustrine environments and exhibit evidence of low-temperature diagenesis. Both John Klein and Cumberland are part of the Sheepbed mudstone at Yellowknife Bay, where the first drilled samples were acquired as well as the first evidence of a habitable environment on Mars. Drilled three meters apart from each other, the two samples reveal basaltic minerals similar to those at Rocknest, as well as phyllosilicates, Fe-oxides/hydroxides, Ca-sulfates, Fe-sulfides, and amorphous materials. The nature and hydration of interlayer cations within the phyllosilicates differs between the two samples, which implies localized diagenesis. The Windjana sandstone at the Kimberley location differs from the Sheepbed mudstone in that it contains more pyroxene and magnetite and abundant K-feldspar, as well as phyllosilicates and amorphous material. These phases may represent potassium-rich basaltic provenance or aqueous alteration by potassium-bearing fluids. While the Confidence Hills sample is still in the preliminary stages of evaluation, major crystalline phases observed in this fine-grained sedimentary rock include plagioclase, pyroxene, K-feldspar and phyllosilicates; hematite, rare in all previous samples, is notably abundant and jarosite is present. The findings suggest localized mobilization of iron-bearing fluids and acidic conditions. The more oxidized assemblage of Confidence Hills marks the transition into the lower strata of Mount Sharp.

Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li{sup +} ion beam-driven hohlraums

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

Fehl, D.L.; Chandler, G.A.; Biggs, F.

X-ray-producing hohlraums are being studied as indirect drives for Inertial Confinement Fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li{sup +} ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The UFO unfold code and its suite of auxiliary functions were used extensively in obtaining time- resolved x-ray spectra and radiation temperatures from this diagnostic. UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfolding parametersmore » (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies ({le} 100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time-history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum.« less

Columnar recombination for X-ray generated electron-holes in amorphous selenium and its significance in a-Se x-ray detectors

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

Bubon, O.; Thunder Bay Regional Research Institute, Thunder Bay, Ontario, P7A 7T1; Jandieri, K.

Although amorphous selenium (a-Se) has a long and successful history of application in optical and X-ray imaging, some of its fundamental properties are still puzzling. In particularly, the mechanism of carrier recombination following x-ray excitation and electric field and temperature dependences of the electron-hole pair creation energy (W{sub ehp}) remain unclear. Using the combination of X-ray photocurrent and pulse height spectroscopy measurements, we measure W{sub ehp} in a wide range of temperatures (218–320 K) and electric fields (10–100 V/µm) and show that the conventional columnar recombination model which assumes Langevin recombination within a column (a primary electron track) fails to explain experimentalmore » results in a wide range of electric fields and temperatures. The reason for the failure of the conventional model is revealed in this work, and the theory of the columnar recombination is modified to include the saturation of the recombination rate at high electric field in order to account for the experimental results in the entire range of fields and temperatures.« less

X-ray Heating and Electron Temperature of Laboratory Photoionized Plasmas

NASA Astrophysics Data System (ADS)

Mancini, Roberto; Lockard, Tom; Mayes, Daniel C.; Loisel, Guillaume; Bailey, James E.; Rochau, Gregory; Abdallah, J.; Golovkin, I.

2018-06-01

In separate experiments performed at the Z facility of Sandia National Laboratories two different samples were employed to produce and characterize photoionized plasmas. One was a gas cell filled with neon, and the other was a thin silicon layer coated with plastic. Both samples were driven by the broadband x-ray flux produced at the collapse of a wire array z-pinch implosion. Transmission spectroscopy of a narrowband portion of the x-ray flux was used to diagnose the charge state distribution, and the electron temperature was extracted from a Li-like ion level population ratio. To interpret the temperature measurement, we performed Boltzmann kinetics and radiation-hydrodynamic simulations. We found that non-equilibrium atomic physics and the coupling of the radiation flux to the atomic level population kinetics play a critical role in modeling the x-ray heating of photoionized plasmas. In spite of being driven by similar x-ray drives, differences of ionization and charged state distributions in the neon and silicon plasmas are reflected in the plasma heating and observed electron temperatures.This work was sponsored in part by DOE Office of Science Grant DE-SC0014451, and the Z Facility Fundamental Science Program of SNL.

Hard X-ray spectrum of Cygnus X-1

NASA Technical Reports Server (NTRS)

Nolan, P. L.; Gruber, D. E.; Knight, F. K.; Matteson, J. L.; Rothschild, R. E.; Marshall, F. E.; Levine, A. M.; Primini, F. A.

1981-01-01

Long-term measurements of the hard X-ray spectrum from 3 keV to 8 MeV of the black-hole candidate Cygnus X-1 in its low state are reported. Observations were made from October 26 to November 18, 1977 with the A2 (Cosmic X-ray) and A4 (Hard X-ray and Low-Energy Gamma-Ray) experiments on board HEAO 1 in the spacecraft's scanning mode. The measured spectrum below 200 keV is found to agree well with previous spectra which have been fit by a model of the Compton scattering of optical or UV photons in a very hot plasma of electron temperature 32.4 keV and optical depth 3.9 or 1.6 for spherical or disk geometry, respectively. At energies above 300 keV, however, flux excess is observed which may be accounted for by a distribution of electron temperatures from 15 to about 100 keV.

Fluid mediated transformation of aragonitic cuttlebone to calcite

NASA Astrophysics Data System (ADS)

Perdikouri, C.; Kasioptas, A.; Putnis, A.

2009-04-01

The aragonite to calcite transition has been studied extensively over the years because of its wide spectra of applications and of its significant geochemical interest. While studies of kinetics (e.g. Topor et al., 1981), thermodynamics (e.g. Wolf et al., 1996) and behavior of ions such as Sr and Mg (e.g. Yoshioka et al., 1986) have been made there are still unanswered questions regarding this reaction especially in the cases where the effects of fluid composition are considered. It is well known that when heated in air, aragonite transforms by a solid state reaction to calcite. The aragonite cuttlebone of the sepia officinalis that was used for our experiments undergoes a phase transition at ~370-390˚ C, measured by in situ heating experiments in a Philips X'pert X-ray powder diffractometer equipped with a HTK 1200 High temperature oven. Successive X-ray scans were taken at isothermal temperatures at 200C intervals. A similar temperature range was found by Vongsavat et al. 2006, who studied this transition in Acropora corals. It is possible however to promote this transition at considerably lower temperatures by means of a fluid mediated reaction where the replacement takes place by a dissolution-precipitation mechanism (Putnis & Putnis, 2007). We have successfully carried out hydrothermal experiments where cuttlebone has been converted to calcite at 200˚ C. Using the PhreeqC program we calculated the required composition of a solution that would be undersaturated with respect to aragonite and saturated with respect to calcite leading to dissolution of the aragonite and to a consequent precipitation of the new calcite phase, similar to the experiments described in an earlier study (Perdikouri et al, 2008). This reaction is not pseudomorphic and results in the destruction of the morphology, presumably due to the molar volume increase. A total transformation of the cuttlebone produced a fine calcite powder. The cuttlebone exhibits a unique microstructure, made up of interconnected chambers. The aragonite grown during biomineralization of the cuttlebone is interlaced with a β-chitin organic phase that provides the framework for the morphology that is observed. Experiments carried out with the same constant conditions but for different periods of time have revealed the evolution of the transformation to calcite. At shorter reaction times the product was made up of calcite powder and of well preserved aragonite septa, as was confirmed by powder X-ray diffraction. In other words, the vertical pillars appear to react at faster rates than the horizontal septa. It has been reported by Florek et al. 2008 that the septa contain higher quantities of β-chitin. The aim of this study is the investigation of these observations and the determination of the effect of the organic component on the kinetics of the aragonite to calcite transformation. Florek M., Fornal E., Gómez-Romero P., Zieba E., Paszkowicz W., Lekki J.,Nowak J., Kuczumow A. Materials Science and Engineering C, In Press (2008) Perdikouri C., Kasioptas A., Putnis C.V., Putnis A. Mineralogical Magazine 72, 111-114 (2008) Putnis A., Putnis C.V. Solid State Chemistry 180, 1783-1786 (2007) Topor N. D., Tolokonnikova L. I., Kadenatsi B. M. Journal of Thermal Analysis 20, 169-174 (1981) Vongsavat V., Winotai P., Meejoo S. Nuclear Instruments and Methods in Physics Research B 243, 167-173 (2006) Wolf G., Lerchner J., Schmidt H., Gamsjäger H., Königsberger E., Schmidt P. Journal of Thermal Analysis 46, 353-359 (1996) Yoshioka S., Ohde S., Kitano Y., Kanamori N. Marine Chemistry 18, 35-48 (1986)

Investigating the Effects of Low Temperature Annealing of Amorphous Corrosion Resistant Alloys.

DTIC Science & Technology

1980-11-01

Ray Diffraction.................................................... 6 Differential Scanning Calorimetry....................................... 9...17 LIST OF FIGURES Figure 1. X- Ray Diffraction Results From Fe32Ni 36Cr 4P 2 B Annealed for One Hour at...Various Temperatures (Cr Ka Radiation) ................................. 7 Figure 2. X- Ray Diffraction Results From FeU2NiaeCr14SieB Annealed for One

Hydrothermal assisted growth of CdSe nanoparticles and study on its dielectric properties

NASA Astrophysics Data System (ADS)

Jamble, Shweta N.; Ghoderao, Karuna P.; Kale, Rohidas B.

2017-11-01

In this work, we have synthesized cadmium selenide (CdSe) nanoparticles by using cadmium chloride (CdCl2) as cadmium ion and sodium selenosulfate (Na2SeSO3) as selenium ion sources through a simple, convenient and cost-effective hydrothermal route at 180 °C temperature for 24 h. Aqueous ammonia was employed as a complex reagent to adjust the pH of the solution. Structural analysis of the obtained product was carried out by using x-ray diffractometer, which revealed that the final product has a cubic structure of CdSe with average crystallite size 13.15 nm. The cauliflower-like CdSe nanostructures were confirmed from the scanning electron microscopy and high-resolution transmission electron microscopy. EDS analysis indicates that the obtained product has a good elemental stoichiometric ratio. The electron diffraction pattern reveals the polycrystalline nature of CdSe. From UV-visible absorption spectral analysis, the optical energy bandgap of CdSe nanoparticles was found to be 1.90 eV. XPS spectra presented Cd 3d3/2, Cd 3d5/2 and Se 3d3/2 peaks at 411.04, 404.29 and 53.52 eV respectively. The CdSe nanoparticles exhibit photoluminescence with two distinct emission bands at 632 nm and 720 nm. FTIR study was used towards the understanding of the formation mechanism and bonding on the surface of the resulting nanoparticles. The dielectric properties of a pelletized sample of CdSe nanoparticles were carried out at room temperature.

Grinding With Diamond Burs and Hydrothermal Aging of a Y-TZP Material: Effect on the Material Surface Characteristics and Bacterial Adhesion.

PubMed

Dutra, Dam; Pereira, Gkr; Kantorski, K Z; Exterkate, Ram; Kleverlaan, C J; Valandro, L F; Zanatta, F B

The aim of this study was to evaluate the effect of grinding with diamond burs and low-temperature aging on the material surface characteristics and bacteria adhesion on a yttrium-stabilized tetragonal zirconia polycrystalline (Y-TZP) surface. Y-TZP specimens were made from presintered blocks, sintered as recommended by the manufacturer, and assigned into six groups according to two factors-grinding (three levels: as sintered, grinding with extra-fine diamond bur [25-μm grit], and grinding with coarse diamond bur [181-μm grit]) and hydrothermal aging-to promote low-temperature degradation (two levels: presence/absence). Phase transformation (X-ray diffractometer), surface roughness, micromorphological patterns (atomic force microscopy), and contact angle (goniometer) were analyzed. Bacterial adhesion (colony-forming units [CFU]/biofilm) was quantified using an in vitro polymicrobial biofilm model. Both the surface treatment and hydrothermal aging promoted an increase in m-phase content. Roughness values increased as a function of increasing bur grit sizes. Grinding with a coarse diamond bur resulted in significantly lower values of contact angle (p<0.05) when compared with the extra-fine and control groups, while there were no differences (p<0.05) after hydrothermal aging simulation. The CFU/biofilm results showed that neither the surface treatment nor hydrothermal aging simulation significantly affected the bacteria adherence (p>0.05). Grinding with diamond burs and hydrothermal aging modified the Y-TZP surface properties; however, these properties had no effect on the amount of bacteria adhesion on the material surface.

Temperature dependence of copper diffusion in different thickness amorphous tungsten/tungsten nitride layer

NASA Astrophysics Data System (ADS)

Asgary, Somayeh; Hantehzadeh, Mohammad Reza; Ghoranneviss, Mahmood

2017-11-01

The amorphous W/WN films with various thickness (10, 30 and 40 nm) and excellent thermal stability were successfully prepared on SiO2/Si substrate with evaporation and reactive evaporation method. The W/WN bilayer has technological importance because of its low resistivity, high melting point, and good diffusion barrier properties between Cu and Si. The thermal stability was evaluated by X-ray diffractometer (XRD) and Scanning Electron Microscope (SEM). In annealing process, the amorphous W/WN barrier crystallized and this phenomenon is supposed to be the start of Cu atoms diffusion through W/WN barrier into Si. With occurrence of the high-resistive Cu3Si phase, the W/WN loses its function as a diffusion barrier. The primary mode of Cu diffusion is the diffusion through grain boundaries that form during heat treatments. The amorphous structure with optimum thickness is the key factor to achieve a superior diffusion barrier characteristic. The results show that the failure temperature increased by increasing the W/WN film thickness from 10 to 30 nm but it did not change by increasing the W/WN film thickness from 30 to 40 nm. It is found that the 10 and 40 nm W/WN films are good diffusion barriers at least up to 800°C while the 30 nm W/WN film shows superior properties as a diffusion barrier, but loses its function as a diffusion barrier at about 900°C (that is 100°C higher than for 10 and 40 nm W/WN films).

Geometrical evidence for dark matter: X-ray constraints on the mass of the elliptical galaxy NGC 720

NASA Astrophysics Data System (ADS)

Buote, David A.; Canizares, Claude R.

1994-05-01

We describe (1) a new test for dark matter and alternate theories of gravitation based on the relative geometries of the X-ray and optical surface brightness distributions and an assumed form for the potential, of the optical light, (2) a technique to measure the shapes of the total gravitating matter and dark matter of an ellipsoidal system which is insensitive to the precise value of the temperature of the gas and to modest temperature gradients, and (3) a new method to determine the ratio of dark mass to stellar mass that is dependent on the functional forms for the visible star, gas and dark matter distributions, but independent of the distance to the galaxy or the gas temperature. We apply these techniques to X-ray data from the ROSAT Position Sensitive Proportional Counter (PSPC) of the optically flattened elliptical galaxy NGC 720; the optical isophotes have ellipticity epsilon approximately 0.40 extending out to approximately 120 sec. The X-ray isophotes are significantly elongated, epsilon = 0.20-0.30 for semimajor axis a approximately 100 sec. The major axes of the optical and X-ray isophotes are misaligned by approximately 30 deg +/- 15 deg. Spectral analysis of the X-ray data reveals no evidence of temperature gradients or anisotropies and demonstrates that a single-temperature plasma (T approximately 0.6 keV) having subsolar heavy element abundances and a two-temperature model having solar abundances describe the spectrum equally well. Considering only the relative geometries of the X-ray and optical surface brightness distributions and an assumed functional form for the potential of the optical light, we conclude that matter distributed like the optical light cannot produce the observed ellipticities of the X-ray isophotes, independent of the gas pressure, the gas temperature, and the value of the stellar mass; this comparison assumes a state of quasi-hydrostatic equilibrium so that the three-dimensional surfaces of the gas emissivity trace the three-dimensional isopotential surfaces -- we discuss the viability of this assumption for NGC 720. Milgrom's Modification of Newtonian Dynamics (MOND) cannot dispel this manifestation of dark matter. Hence, geometrical considerations require, without mention of pressure or temperature, the presence of an extended, massive dark matter halo in NGC 720. Employing essentially the technique of Buote & Canizares (1992; Buote 1992) we use the shape of the X-ray surface brightness to constrain the shape of the total gravitating matter. The total matter is modeled as either an oblate or prolate spheriod of constant shape and orientation having either a Ferrers (rho approximately r-n) or Hernquist density. Assuming the X-ray gas is in hydrostatic equilibrium, we construct a model X-ray gas distribution for various temperature profiles. We determine the ellipticity of the total gravitating matter to be epsilon approximately 0.50-0.70. Using the single-temperature model we estimate a total mass approximately (0.41-1.4) x 1012 h80 solar mass interior to the ellipsoid of semimajor axis 43.6 h80 kpc. Ferrers densities as steep as r-3 do not fit the data, but the r-2 and Hernquist models yield excellent fits. We estimate the mass distributions of the stars and the gas and fit the dark matter directly. For a given gas equation of state and functional forms for the visible stars, gas, and dark matter, these models yield a distance-independent and temperature-independent measurement of the ratio of dark mass to stellar mass MDM/Mstars. We estimate a minimum MDM/Mstars greater than or equal to 4 which corresponds to a total mass slightly greater than that derived from the single-temperature models for distance D = 20h80 Mpc.

Geometrical evidence for dark matter: X-ray constraints on the mass of the elliptical galaxy NGC 720

NASA Technical Reports Server (NTRS)

Buote, David A.; Canizares, Claude R.

1994-01-01

We describe (1) a new test for dark matter and alternate theories of gravitation based on the relative geometries of the X-ray and optical surface brightness distributions and an assumed form for the potential, of the optical light, (2) a technique to measure the shapes of the total gravitating matter and dark matter of an ellipsoidal system which is insensitive to the precise value of the temperature of the gas and to modest temperature gradients, and (3) a new method to determine the ratio of dark mass to stellar mass that is dependent on the functional forms for the visible star, gas and dark matter distributions, but independent of the distance to the galaxy or the gas temperature. We apply these techniques to X-ray data from the ROSAT Position Sensitive Proportional Counter (PSPC) of the optically flattened elliptical galaxy NGC 720; the optical isophotes have ellipticity epsilon approximately 0.40 extending out to approximately 120 sec. The X-ray isophotes are significantly elongated, epsilon = 0.20-0.30 for semimajor axis a approximately 100 sec. The major axes of the optical and X-ray isophotes are misaligned by approximately 30 deg +/- 15 deg. Spectral analysis of the X-ray data reveals no evidence of temperature gradients or anisotropies and demonstrates that a single-temperature plasma (T approximately 0.6 keV) having subsolar heavy element abundances and a two-temperature model having solar abundances describe the spectrum equally well. Considering only the relative geometries of the X-ray and optical surface brightness distributions and an assumed functional form for the potential of the optical light, we conclude that matter distributed like the optical light cannot produce the observed ellipticities of the X-ray isophotes, independent of the gas pressure, the gas temperature, and the value of the stellar mass; this comparison assumes a state of quasi-hydrostatic equilibrium so that the three-dimensional surfaces of the gas emissivity trace the three-dimensional isopotential surfaces -- we discuss the viability of this assumption for NGC 720. Milgrom's Modification of Newtonian Dynamics (MOND) cannot dispel this manifestation of dark matter. Hence, geometrical considerations require, without mention of pressure or temperature, the presence of an extended, massive dark matter halo in NGC 720. Employing essentially the technique of Buote & Canizares (1992; Buote 1992) we use the shape of the X-ray surface brightness to constrain the shape of the total gravitating matter. The total matter is modeled as either an oblate or prolate spheriod of constant shape and orientation having either a Ferrers (rho approximately r(exp -n)) or Hernquist density. Assuming the X-ray gas is in hydrostatic equilibrium, we construct a model X-ray gas distribution for various temperature profiles. We determine the ellipticity of the total gravitating matter to be epsilon approximately 0.50-0.70. Using the single-temperature model we estimate a total mass approximately (0.41-1.4) x 10(exp 12) h(sub 80) solar mass interior to the ellipsoid of semimajor axis 43.6 h(sub 80) kpc. Ferrers densities as steep as r(exp -3) do not fit the data, but the r(exp -2) and Hernquist models yield excellent fits. We estimate the mass distributions of the stars and the gas and fit the dark matter directly. For a given gas equation of state and functional forms for the visible stars, gas, and dark matter, these models yield a distance-independent and temperature-independent measurement of the ratio of dark mass to stellar mass M(sub DM)/M(sub stars). We estimate a minimum M(sub DM)/M(sub stars) greater than or equal to 4 which corresponds to a total mass slightly greater than that derived from the single-temperature models for distance D = 20h(sub 80) Mpc.

Infrared and X-Ray Spectroscopy of the Kes 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties

NASA Astrophysics Data System (ADS)

Temim, Tea; Slane, Patrick; Arendt, Richard G.; Dwek, Eli

2012-01-01

We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of ~1.5 keV, or with two thermal components with temperatures of 1.5 and 0.2 keV. Previous studies suggest that the hot component may originate from reverse-shocked supernova (SN) ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from SN ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and IR emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of ~140 K by a relatively dense, hot plasma that also gives rise to the hot X-ray emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-ray emitting gas. The total mass of the warm dust component is at least 1.3 × 10-2 M ⊙, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative estimates of density and filling factors of the clumpy medium swept up by the SNR.

Intensity correlation measurement system by picosecond single shot soft x-ray laser.

PubMed

Kishimoto, Maki; Namikawa, Kazumichi; Sukegawa, Kouta; Yamatani, Hiroshi; Hasegawa, Noboru; Tanaka, Momoko

2010-01-01

We developed a new soft x-ray speckle intensity correlation spectroscopy system by use of a single shot high brilliant plasma soft x-ray laser. The plasma soft x-ray laser is characterized by several picoseconds in pulse width, more than 90% special coherence, and 10(11) soft x-ray photons within a single pulse. We developed a Michelson type delay pulse generator using a soft x-ray beam splitter to measure the intensity correlation of x-ray speckles from materials and succeeded in generating double coherent x-ray pulses with picosecond delay times. Moreover, we employed a high-speed soft x-ray streak camera for the picosecond time-resolved measurement of x-ray speckles caused by double coherent x-ray pulse illumination. We performed the x-ray speckle intensity correlation measurements for probing the relaxation phenomena of polarizations in polarization clusters in the paraelectric phase of the ferroelectric material BaTiO(3) near its Curie temperature and verified its performance.

OSO 8 X-ray spectra of clusters of galaxies. II - Discussion

NASA Technical Reports Server (NTRS)

Smith, B. W.; Mushotzky, R. F.; Serlemitsos, P. J.

1979-01-01

An observational description of X-ray clusters of galaxies is given based on OSO 8 X-ray results for spatially integrated spectra of 20 such clusters and various correlations obtained from these results. It is found from a correlation between temperature and velocity dispersion that the X-ray core radius should be less than the galaxy core radius or, alternatively, that the polytropic index is about 1.1 for most of the 20 clusters. Analysis of a correlation between temperature and emission integral yields evidence that more massive clusters accumulate a larger fraction of their mass as intracluster gas. Galaxy densities and optical morphology, as they correlate with X-ray properties, are reexamined for indications as to how mass injection by galaxies affects the density structure of the gas. The physical arguments used to derive iron abundances from observed equivalent widths of iron line features in X-ray spectra are critically evaluated, and the associated uncertainties in abundances derived in this manner are estimated to be quite large.

The Miniature X-ray Solar Spectrometer (MinXSS) CubeSats: New soft X-ray spectrometer to investigate properties of hot plasma in the quiet Sun, active regions, and flares.

NASA Astrophysics Data System (ADS)

Moore, C. S.; Dennis, B. R.; Woods, T. N.

2017-12-01

Detection of soft X-rays from the Sun provides direct information on coronal plasma at temperatures in excess of 1 MK. The Miniature X-ray Solar Spectrometer (MinXSS) CubeSats provides new spectrally resolved measurements from 0.8 -12 keV. The MinXSS spectral resolving power (R 40 at 5.9 keV) allows plasma abundances to be determined for Fe, Mg, Ni, Ca, Si, S, and Ar. Long-term temporal variations during quiet-Sun times allow active region contributions to be extracted from the full solar flux. The MinXSS 10 second time cadence allows short-term variations of the soft X-ray flux, temperature, and abundances to be determined during flares. The MinXSS spectroscopic observations, combined with the imaging spectroscopy from the Hinode X-ray Telescope (XRT) and the Reuven Ramaty Solar Spectroscopic Imager (RHESSI), hold great potential for advancing our understanding of solar dynamics.

Effect of Pressure on Valence and Structural Properties of YbFe 2 Ge 2 Heavy Fermion Compound—A Combined Inelastic X-ray Spectroscopy, X-ray Diffraction, and Theoretical Investigation

DOE PAGES

Kumar, Ravhi S.; Svane, Axel; Vaitheeswaran, Ganapathy; ...

2015-10-19

We measured the crystal structure and the Yb valence of the YbFe 2Ge 2 heavy fermion compound at room temperature and under high pressures using high-pressure powder X-ray diffraction and X-ray absorption spectroscopy via both partial fluorescence yield and resonant inelastic X-ray emission techniques. Moreover, the measurements are complemented by first-principles density functional theoretical calculations using the self-interaction corrected local spin density approximation investigating in particular the magnetic structure and the Yb valence. Finally, while the ThCr 2Si 2-type tetragonal (I4/mmm) structure is stable up to 53 GPa, the X-ray emission results show an increase of the Yb valence frommore » v = 2.72(2) at ambient pressure to v = 2.93(3) at ~9 GPa, where at low temperature a pressure-induced quantum critical state was reported.« less

Novel Chalcogenide Materials for X-ray and Gamma-ray Detection

DTIC Science & Technology

2016-05-01

53 Novel Chalcogenide Materials for x-ray and y-ray Detection Distribution Statement A. Approved for public release; distribution is unlimited. 0...TITLE AND SUBTITLE Sa. CONTRACT NUMBER Novel Chalcogenide Materials for x-ray and y-ray Detection Sb. GRANT NUMBER HDTRA 1-09-1-0044 Sc. PROGRAM...heavy atom chalcogenide family of semiconductors for room temperature gamma radiation detection . Its goal was to accelerate nuclear detector material

The Influence of Growth Temperature on Sb Incorporation in InAsSb, and the Temperature-dependent Impact of Bi Surfactants

DTIC Science & Technology

2014-01-01

resolution X - ray diffraction (XRD) were collected for all samples, and reciprocal space maps (RSMs) were collected from selected samples. The complete data...exposure. The lines represent the model fit. 19 13 Figure 1. Triple axis x - ray diffraction from the bi-layered InAsSb structures grown on GaSb at...Applied Physics, Structural properties of bismuth‐bearing semiconductor alloys, 63 (1988) 107. 18 12 Figure Captions Figure 1. Triple axis x - ray

X ray and gamma ray emission from classical nova outbursts

NASA Technical Reports Server (NTRS)

Truran, James W.; Starrfield, Sumner; Sparks, Warren M.

1992-01-01

The outbursts of classical novae are now recognized to be consequences of thermonuclear runaways proceeding in accreted hydrogen-rich shells on white dwarfs in close binary systems. For the conditions that are known to exist in these environments, it is expected that soft x-rays can be emitted, and indeed x-rays were detected from a number of novae. The circumstances for which we expect novae to produce significant x-ray fluxes and provide estimates of the luminosities and effective temperatures are described. It is also known that at the high temperatures that are known to be achieved in this explosive hydrogen-burning environment, significant production of both Na-22 and Al-26 will occur. In this context, we identify the conditions for which gamma-ray emission may be expected to result from nova outbursts.

Eta Carinae: X-ray Line Variations during the 2003 X-ray Minimum, and the Orbit Orientation

NASA Technical Reports Server (NTRS)

Corcoran, M. F.; Henley, D.; Hamaguchi, K.; Khibashi, K.; Pittard, J. M.; Stevens, I. R.; Gull, T. R.

2007-01-01

The future evolution of Eta Carinae will be as a supernova (or hypernova) and black hole. The evolution is highly contingent on mass and angular momentum changes and instabilities. The presence of a companion can serve to trigger instabilities and provide pathways for mass and angular momentum exchange loss. X-rays can be used a a key diagnostic tool: x-ray temperatures trace pre-shock wind velocities, periodic x-ray variability traces the orbit, and x-ray line variations traces the flow and orientation of shocked gas. This brief presentation highlights x-ray line variations from the HETG and presents a model of the colliding wind flow.

The temperature and density structures of an X-ray flare during the decay phase. [Skylab observations

NASA Technical Reports Server (NTRS)

Silk, J. K.; Kahler, S. W.; Krieger, A. S.; Vaiana, G. S.

1976-01-01

The X-ray flare of 9 August 1973 was characterized by a spatially small kernel structure which persisted throughout its duration. The decay phase of this flare was observed in the objective grating mode of the X-ray telescope aboard the Skylab. Data analysis was carried out by scanning the images with a microdensitometer, converting the density arrays to energy using laboratory film calibration data and taking cross sections of the energy images. The 9 August flare shows two distinct periods in its decay phase, involving both cooling and material loss. The objective grating observations reveal that the two phenomena are separated in time. During the earlier phase of the flare decay, the distribution of emission measure as a function of temperature is changing, the high temperature component of the distribution being depleted relative to the cooler body of plasma. As the decay continues, the emission measure distribution stabilizes and the flux diminishes as the amount of material at X-ray emitting temperatures decreases.

Chandra Detects Enigmatic Point X-ray Sources in the Cat's Eye and the Helix Nebulae

NASA Astrophysics Data System (ADS)

Guerrero, M. A.; Gruendl, R. A.; Chu, Y.-H.; Kaler, J. B.; Williams, R. M.

2000-12-01

Central stars of planetary nebulae (PNe) with Teff greater than 100,000 K are expected to emit soft X-rays that peak below 0.1 keV. Chandra ACIS-S observations of the Cat's Eye Nebula (NGC 6543) and the Helix Nebula (NGC 7293) have detected point X-ray sources at their central stars. The point X-ray source at the central star of the Cat's Eye is both unknown previously and unexpected because the stellar temperature is only ~50,000 K. In contrast, the point X-ray source at the central star of the Helix was previously detected by ROSAT and its soft X-ray emission is expected because the stellar temperature is ~100,000 K. However, the Helix X-ray source also shows a harder X-ray component peaking at 0.8 keV that is unexpected and for which Chandra has provided the first high-resolution spectrum for detailed analysis. The spectra of the point X-ray sources in the Cat's Eye and the Helix show line features indicating an origin of thermal plasma emission. The spectrum of the Helix source can be fit by Raymond & Smith's model of plasma emission at ~9*E6 K. The spectrum of the Cat's Eye source has too few counts for a spectral fit, but appears to be consistent with plasma emission at 2-3*E6 K. The X-ray luminosities of both sources are ~5*E29 erg s-1. The observed plasma temperatures are too high for accretion disks around white dwarfs, but they could be ascribed to coronal X-ray emission. While central stars of PNe are not known to have coronae, the observed spectra are consistent with quiescent X-ray emission from dM flare stars. On the other hand, neither the central star of the Helix or the Cat's Eye are known to have a binary companion. It is possible that the X-rays from the Cat's Eye's central star originate from shocks in the stellar wind, but the central star of the Helix does not have a measurable fast stellar wind. This work is supported by the CXC grant number GO0-1004X.

X-ray diffraction study of the caged magnetic compound DyFe 2 Zn 20 at low temperatures

NASA Astrophysics Data System (ADS)

Ohashi, M.; Ohashi, K.; Sawabu, M.; Miyagawa, M.; Maeta, K.; Isikawa, Y.

2018-05-01

We have carried out high-angle X-ray powder diffraction measurements of the caged magnetic compound DyFe2Zn20 at low temperature between 14 and 300 K. Even though a strong magnetic anisotropy exists in the magnetization and magnetic susceptibility due to strong exchange interaction between Fe and Dy, almost all X-ray powder diffraction peaks correspond to Bragg reflections of the cubic structural models not only at room temperature paramagnetic state but also at low temperature magnetic ordering state. The Debye temperature is obtained to be 227 K from the results of the volumetric thermal expansion coefficient, which is approximately coincident with that of CeRu2Zn20 (245 K) and that of pure Zn metal (235 K).

Overview of the Chandra X-Ray Observatory Facility

NASA Technical Reports Server (NTRS)

Weisskopf, M. C.; Six, N. Frank (Technical Monitor)

2002-01-01

The Chandra X-Ray Observatory (originally called the Advanced X-Ray Astrophysics Facility - AXAF) is the X-Ray component of NASA's "Great Observatory" Program. Chandra is a NASA facility that provides scientific data to the international astronomical community in response to scientific proposals for its use. The Observatory is the product of the efforts of many organizations in the United States and Europe. The Great Observatories also include the Hubble Space Telescope for space-based observations of astronomical objects primarily in the visible portion of the electromagnetic spectrum, the now defunct Compton Gamma- Ray Observatory that was designed to observe gamma-ray emission from astronomical objects, and the soon-to-be-launched Space Infrared Telescope Facility (SIRTF). The Chandra X-Ray Observatory (hereafter CXO) is sensitive to X-rays in the energy range from below 0.1 to above 10.0 keV corresponding to wavelengths from 12 to 0.12 nanometers. The relationship among the various parts of the electromagnetic spectrum, sorted by characteristic temperature and the corresponding wavelength, is illustrated. The German physicist Wilhelm Roentgen discovered what he thought was a new form of radiation in 1895. He called it X-radiation to summarize its properties. The radiation had the ability to pass through many materials that easily absorb visible light and to free electrons from atoms. We now know that X-rays are nothing more than light (electromagnetic radiation) but at high energies. Light has been given many names: radio waves, microwaves, infrared, visible, ultraviolet, X-ray and gamma radiation are all different forms. Radio waves are composed of low energy particles of light (photons). Optical photons - the only photons perceived by the human eye - are a million times more energetic than the typical radio photon, whereas the energies of X-ray photons range from hundreds to thousands of times higher than that of optical photons. Very low temperature systems (hundreds of degrees below zero Celsius) produce low energy radio and microwave photons, whereas cool bodies like our own (about 30 degrees Celsius) produce infrared radiation. Very high temperatures (millions of degrees Celsius) are one way of producing X-rays.

Wide Bandgap Semiconductor Detector Optimization for Flash X-Ray Measurements

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

Roecker, Caleb Daniel; Schirato, Richard C.

2017-11-17

Charge trapping, resulting in a decreased and spatially dependent electric field, has long been a concern for wide bandgap semiconductor detectors. While significant work has been performed to characterize this degradation at varying temperatures and radiation environments, this work concentrates upon examining the event-to-event response in a flash X-ray environment. The following work investigates if charge trapping is a problem for CZT detectors, with particular emphasis on flash X-ray radiation fields at cold temperatures. Results are compared to a non-flash radiation field, using an Am-241 alpha source and similar temperature transitions. Our ability to determine if a response change occurredmore » was hampered by the repeatability of our flash X-ray systems; a small response change was observed with the Am-241 source. Due to contrast of these results, we are in the process of revisiting the Am-241 measurements in the presence of a high radiation environment. If the response change is more pronounced in the high radiation environment, a similar test will be performed in the flash X-ray environment.« less

Solvothermal synthesis of nickel-tungsten sulfides for 2-propanol dehydration.

PubMed

Gómez-Gutiérrez, Claudia M; Luque, P A; Guerra-Rivas, G; López-Sánchez, J A; Armenta, M A; Quintana, J M; Olivas, A

2015-01-01

The bimetallic nickel-tungsten catalysts were prepared via solvothermal method. The X-ray Diffractometer (XRD) analysis revealed that the corresponding peaks at 14°, 34°, and 58° were for tungsten disulfide (WS2 ) hexagonal phase. The catalysts displayed different crystalline phase with nickel addition, and as an effect the WS2 surface area decreased from 74.7 to 2.0 m(2) g(--1) . In this sense, high-resolution transmission electron microscopy (HRTEM) showed the layers set in direction (002) with an onion-like morphology, and in the center of the particles there is a large amount of nickel contained with 6-8 layers covering it. The catalytic dehydration of 2-propanol was selective to propene in 100% at 250 °C for the sample with 0.7 of atomic ratio of Ni/Ni + W. © Wiley Periodicals, Inc.

Structural and optical studies of CuO nanostructures

NASA Astrophysics Data System (ADS)

Chand, Prakash; Gaur, Anurag; Kumar, Ashavani

2014-04-01

In the present study, copper oxide (CuO) nanostructures have been synthesized at 140 °C for different aging periods, 1, 24, 48 and 96 hrs by hydrothermal method to investigate their effects on structural and optical properties. The X-ray diffractometer (XRD) pattern indicates the pure phase formation of CuO and the particle size, calculated from XRD data, has been found to be increasing from 21 to 36 nm for the samples synthesized at different aging periods. Field emission scanning electron microscope (FESEM) analysis also shows that the average diameter and length of these rectangular nano flakes increases with increasing the aging periods. Moreover Raman spectrums also confirm the phase formation of CuO. The optical band gaps calculated through UV-visible spectroscopy are found to be decreasing from 2.92 to 2.69 eV with increase in aging periods, 1 to 96 hrs, respectively.

In situ synthesis of hydroxyapatite coating by laser cladding.

PubMed

Wang, D G; Chen, C Z; Ma, J; Zhang, G

2008-10-15

HA bioceramic coatings were synthesized on titanium substrate by laser cladding using cheap calcium carbonate and calcium hydrogen phosphate. The thermodynamic condition for synthesizing HA was calculated by software Matlab 5.0, the microstructure and phase analysis of laser clad HA bioceramic coatings were studied by electron probe microanalyser (EPMA), X-ray diffractometer (XRD) and transmission electron microscopy (TEM). The theoretical results show that the Gibbs free enthalpy for the synthesis of HA phase is satisfied, and the presence of HA phase in the clad coatings was then further verified by XRD and the selected area diffraction patterns. When the laser power is 600W and the scanning speed is 3.5mm/s, the compact HA bioceramic coatings were obtained, which have cellular dendritic structure and consist of the phases of HA, alpha-Ca(2)P(2)O(7), CaO and CaTiO(3).

Confidence Hills Mineralogy and Chemin Results from Base of Mt. Sharp, Pahrump Hills, Gale Crater, Mars

NASA Technical Reports Server (NTRS)

Cavanagh, P. D.; Bish, D. L.; Blake, D. F.; Vaniman, D. T.; Morris, R. V.; Ming, D. W.; Rampe, E. B.; Achilles, C. N.; Chipera, S. J.; Treiman, A. H.;

Thermal Conductivity on the Nanofluid of Graphene and Silver Nanoparticles Composite Material.

PubMed

Myekhlai, Munkhshur; Lee, Taejin; Baatar, Battsengel; Chung, Hanshik; Jeong, Hyomin

2016-02-01

The composite material consisted of graphene (GN) and silver nanoparticles (AgNPs) has been essential topic in science and industry due to its unique thermal, electrical and antibacterial proper- ties. However, there are scarcity studies based on their thermal properties of nanofluids. Therefore, GN-AgNPs composite material was synthesized using facile and environment friendly method and further nanofluids were prepared by ultrasonication in this study. The morphological and structural investigations were carried out using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD) as well as ultra violet (UV)-visible spectroscopy. Furthermore, thermal conductivity measurements were performed for as-prepared nanofluids. As a result of thermal conductivity study, GN-AgNPs composite material was considerably enhanced the thermal conductivity of base fluid (water) by to 6.59% for the nanofluid (0.2 wt% GN and 0.4 wt% AgNPs).

Acenaphthenequinone thiosemicarbazone and its transition metal complexes: synthesis, structure, and biological activity.

PubMed

Rodriguez-Argüelles, M C; Belicchi Ferrari, M; Gasparri Fava, G; Pelizzi, C; Pelosi, G; Albertini, R; Bonati, A; Dall'Aglio, P P; Lunghi, P; Pinelli, S

1997-04-01

The reaction of iron, nickel, copper, and zinc chlorides or acetates with acenaphthenequinone thiosemicarbazone, Haqtsc leads to the formation of novel complexes that have been characterized by spectroscopic studies (NMR, IR) and biological properties. The crystal structures of the free ligand Haqtsc 1 and of the compound [Ni(aqtsc)2].DMF 2, have also been determined by X-ray methods from diffractometer data. In 1, the conformation of the two nonequivalent molecules is governed by intramolecular hydrogen bonds, while an intermolecular hydrogen bond is responsible for dimer-like groups formation. In 2, the coordination geometry about nickel is distorted octahedral, and the two ligand molecules are terdentate monodeprotonated. Biological studies have shown that, for the first time at least up the used doses, a free ligand is active both in the inhibition of cell proliferation and in the induced differentiation on Friend erythroleukemia cells (FLC).

Effects of various applied voltages on physical properties of TiO2 nanotubes by anodization method

NASA Astrophysics Data System (ADS)

Hoseinzadeh, T.; Ghorannevis, Z.; Ghoranneviss, M.; Sari, A. H.; Salem, M. K.

2017-09-01

Three steps anodization process is used to synthesize highly ordered and uniform multilayered titanium oxide (TiO2) nanotubes and effect of different anodization voltages are studied on their physical properties such as structural, morphological and optical. The crystalized structure of the synthesized tubes is investigated by X-ray diffractometer analysis. To study the morphology of the tubes, field emission scanning electron microscopy is used, which showed that the wall thicknesses and the diameters of the tubes are affected by the different anodization voltages. Moreover, optical studies performed by diffuse reflection spectra suggested that band gap of the TiO2 nanotubes are also changed by applying different anodization voltages. In this study using physical investigations, an optimum anodization voltage is obtained to synthesize the uniform crystalized TiO2 nanotubes with suitable diameter, wall thickness and optical properties.

Development of in-Situ Al-Si/CuAl₂ Metal Matrix Composites: Microstructure, Hardness, and Wear Behavior.

PubMed

Tash, Mahmoud M; Mahmoud, Essam R I

2016-06-02

In the present work, in-situ metal matrix composites were fabricated through squeeze casting. The copper particles were dispersed with different weight percentages (3%, 6%, 10%, and 15%) into Al-12% Si piston alloy. Also, heat treatments were performed at 380 °C and 450 °C for holding times of 6 and 18 h. The microstructures, X-ray diffractometer (XRD) pattern, hardness, and wear characteristics were evaluated. The results showed that these copper particles have reacted with the aluminum under all of the aforementioned processing conditions resulting in the formation of fine copper aluminide intermetallics. Most of the intermetallics were CuAl₂, while AlCu appeared in a small ratio. Additionally, these intermetallics were homogenously distributed within the alloy matrix with up to 6% Cu addition. The amounts of those intermetallics increased after performing heat treatment. Most of these intermetallics were CuAl₂ at 380 °C, while the Cu-rich intermetallics appeared at 450 °C. Increasing the holding time to 18 h, however, led to grain coarsening and resulted in the formation of some cracks. The hardness of the resulting composite materials was improved. The hardness value reached to about 170 HV after heat treating at 380 °C for 8 h. The wear resistance of the resulting composite materials was remarkably improved, especially at lower additions of Cu and at the lower heat treatment temperature.

Spectral and Temporal Characteristics of X-Ray-Bright Stars in the Pleiades

NASA Technical Reports Server (NTRS)

Gagne, Marc; Caillault, Jean-Pierre; Stauffer, John R.

1995-01-01

We follow up our deep ROSAT imaging survey of the Pleiades (Stauffer et al. 1994) with an analysis of the spectral and temporal characteristics of the X-ray-bright stars in the Pleiades. Raymond & Smith (1977) one and two-temperature models have been used to fit the position-sensitive proportional counter (PSPC) pulse-height spectra of the dozen or so brightest sources associated with late-type Pleiades members. The best-fit temperatures suggest hot coronal temperatures for K, M, and rapidly rotating G stars, and cooler temperatures for F and slowly rotating G stars. In order to probe the many less X-ray-luminous stars, we have generated composite spectra by combining net counts from all Pleiades members according to spectral type and rotational velocity. Model fits to the composite spectra confirm the trend seen in the individual spectral fits. Particularly interesting is the apparent dependence of coronal temperature on L(sub x)/L(sub bol). A hardness-ratio analysis also confirms some of these trends. The PSPC data have also revealed a dozen or so strong X-ray flares with peak X-ray luminosities in excess of approx. 10(exp 30) ergs/sec. We have modeled the brightest of these flares with a simple quasi-static cooling loop model. The peak temperature and emission measure and the inferred electron density and plasma volume suggest a very large scale flaring event. The PSPC data were collected over a period of approx. 18 months, allowing us to search for source variability on timescales ranging from less than a day (in the case of flares) to more than a year between individual exposures. On approximately year-long timescales, roughly 25% of the late-type stars are variable. Since the Pleiades was also intensively monitored by the imaging instruments on the Einstein Observatory, we have examined X-ray luminosity variations on the 10 yr timescale between Einstein and ROSAT and find that up to 40% of the late-type stars are X-ray variable. Since there is only marginal evidence for increased variability on decade-long timescales, the variability observed on long and short timescales may have a common physical origin.

Infrared and X-Ray Spectroscopy of the Kes 75 Supernova Remnant Shell: Characterizing the Dust and Gas Properties

NASA Technical Reports Server (NTRS)

Temim, Tea; Slane, Patrick; Arendt, Richard G.; Dwek, Eli

2011-01-01

We present deep Chandra observations and Spitzer Space Telescope infrared (IR) spectroscopy of the shell in the composite supernova remnant (SNR) Kes 75 (G29.7-0.3). The remnant is composed of a central pulsar wind nebula and a bright partial shell in the south that is visible at radio, IR, and X-ray wavelengths. The X-ray emission can be modeled by either a single thermal component with a temperature of approximately 1.5 keY, or with two thermal components with temperatures of 1.5 and 0.2 keY. Previous studies suggest that the hot component may originate from reverse-shocked supernova (SN) ejecta. However, our new analysis shows no definitive evidence for enhanced abundances of Si, S, Ar, Mg, and Fe, as expected from SN ejecta, or for the IR spectral signatures characteristic of confirmed SN condensed dust, thus favoring a circumstellar or interstellar origin for the X-ray and IR emission. The X-ray and IR emission in the shell are spatially correlated, suggesting that the dust particles are collisionally heated by the X-ray emitting gas. The IR spectrum of the shell is dominated by continuum emission from dust with little, or no line emission. Modeling the IR spectrum shows that the dust is heated to a temperature of approximately 140 K by a relatively dense, hot plasma that also gives rise to the hot X-my emission component. The density inferred from the IR emission is significantly higher than the density inferred from the X-ray models, suggesting a low filling factor for this X-my emitting gas. The total mass of the warm dust component is at least 1.3 x 10(exp -2) x solar mass, assuming no significant dust destruction has occurred in the shell. The IR data also reveal the presence of an additional plasma component with a cooler temperature, consistent with the 0.2 keV gas component. Our IR analysis therefore provides an independent verification of the cooler component of the X-ray emission. The complementary analyses of the X-ray and IR emission provide quantitative estimates of density and filling factors of the clumpy medium swept up by the SNR.

Amorphous boron gasket in diamond anvil cell research

NASA Astrophysics Data System (ADS)

Lin, Jung-Fu; Shu, Jinfu; Mao, Ho-kwang; Hemley, Russell J.; Shen, Guoyin

2003-11-01

Recent advances in high-pressure diamond anvil cell experiments include high-energy synchrotron x-ray techniques as well as new cell designs and gasketing procedures. The success of high-pressure experiments usually depends on a well-prepared sample, in which the gasket plays an important role. Various gasket materials such as diamond, beryllium, rhenium, and stainless steel have been used. Here we introduce amorphous boron as another gasket material in high-pressure diamond anvil cell experiments. We have applied the boron gasket for laser-heating x-ray diffraction, radial x-ray diffraction, nuclear resonant inelastic x-ray scattering, and inelastic x-ray scattering. The high shear strength of the amorphous boron maximizes the thickness of the sample chamber and increases the pressure homogeneity, improving the quality of high-pressure data. Use of amorphous boron avoids unwanted x-ray diffraction peaks and reduces the absorption of incident and x rays exiting the gasket material. The high quality of the diffraction patterns makes it possible to refine the cell parameters with powder x-ray diffraction data under high pressure and high temperature. The reactivity of boron prevents its use at high temperatures, however. When heated, boron may also react with the specimen to produce unwanted phases. The relatively porous boron starting material at ambient conditions also poses some challenges for sample preparation.

The evolution of X-ray clusters in a cold plus hot dark matter universe

NASA Technical Reports Server (NTRS)

Bryan, Greg L.; Klypin, Anatoly; Loken, Chris; Norman, Michael L.; Burns, Jack O.

1994-01-01

We present the first self-consistently computed results on the evolution of X-ray properties of galaxy clusters in a cold + hot dark matter (CHDM) model. We have performed a hydrodynamic plus N-body simulation for the COBE-compatible CHDM model with standard mass components: Omega(sub hot) = 0.3, Omega (sub cold) = 0.6 and Omega(sub baryon) = 0.1 (h = 0.5). In contrast with the CDM model, which fails to reproduce the observed temperature distribution function dN/dT (Bryan et al. 1994b), the CHDM model fits the observational dN/dT quite well. Our results on X-ray luminosity are less firm but even more intriguing. We find that the resulting X-ray luminosity functions at redshifts z = 0.0, 0.2, 0.4, 0.7 are well fit by observations, where they overlap. The fact that both temperatures and luminosities provide a reasonable fit to the available observational data indicates that, unless we are missing some essential physics, there is neither room nor need for a large fraction of gas in rich clusters: 10% (or less) in baryons is sufficient to explain their X-ray properties. We also see a tight correlation between X-ray luminosity and gas temperature.

The Temporal Development of Dust Formation and Destruction in Nova Sagittarii 2015#2 (V5668 SGR): A Panchromatic Study

NASA Astrophysics Data System (ADS)

Gehrz, R. D.; Evans, A.; Woodward, C. E.; Helton, L. A.; Banerjee, D. P. K.; Srivastava, M. K.; Ashok, N. M.; Joshi, V.; Eyres, S. P. S.; Krautter, Joachim; Kuin, N. P. M.; Page, K. L.; Osborne, J. P.; Schwarz, G. J.; Shenoy, D. P.; Shore, S. N.; Starrfield, S. G.; Wagner, R. M.

2018-05-01

We present 5–28 μm SOFIA FORECAST spectroscopy complemented by panchromatic X-ray through infrared observations of the CO nova V5668 Sgr documenting the formation and destruction of dust during ∼500 days following outburst. Dust condensation commenced by 82 days after outburst at a temperature of ∼1090 K. The condensation temperature indicates that the condensate was amorphous carbon. There was a gradual decrease of the grain size and dust mass during the recovery phase. Absolute parameter values given here are for an assumed distance of 1.2 kpc. We conclude that the maximum mass of dust produced was 1.2 × 10‑7 M ⊙ if the dust was amorphous carbon. The average grain radius grew to a maximum of ∼2.9 μm at a temperature of ∼720 K around day 113 when the shell visual optical depth was τ v ∼ 5.4. Maximum grain growth was followed by a period of grain destruction. X-rays were detected with Swift from day 95 to beyond day 500. The Swift X-ray count rate due to the hot white dwarf peaked around day 220, when its spectrum was that of a kT = 35 eV blackbody. The temperature, together with the supersoft X-ray turn-on and turn-off times, suggests a white dwarf mass of ∼1.1 M ⊙. We show that the X-ray fluence was sufficient to destroy the dust. Our data show that the post-dust event X-ray brightening is not due to dust destruction, which certainly occurred, as the dust is optically thin to X-rays.

Real-time x-ray scattering study of the initial growth of organic crystals on polymer brushes

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

An, Sung Yup; Ahn, Kwangseok; Kim, Doris Yangsoo

2014-04-21

We studied the early-stage growth structures of pentacene organic crystals grown on polymer brushes using real-time x-ray scattering techniques. In situ x-ray reflectivity and atomic force microscopy analyses revealed that at temperatures close to the glass transition temperature of polymer brush, the pentacene overlayer on a polymer brush film showed incomplete condensation and 3D island structures from the first monolayer. A growth model based on these observations was used to quantitatively analyze the real-time anti-Bragg x-ray scattering intensities measured during pentacene growth to obtain the time-dependent layer coverage of the individual pentacene monolayers. The extracted total coverage confirmed significant desorptionmore » and incomplete condensation in the pentacene films deposited on the polymer brushes. These effects are ascribed to the change in the surface viscoelasticity of the polymer brushes around the glass transition temperature.« less

Changes in the electrical properties of pure and doped polymers under the influence of small doses of X-rays

NASA Astrophysics Data System (ADS)

Mahmoud, S. A.; Madi, N. K.; Kassem, M. E.; El-Khatib, A.

A study has been made of the temperature dependence of the d.c. conductivity of pure and borated low density polyethylene LDPE (4% and 8% borax). The above calculations were carried out before and after X-ray irradiation. The irradiation dose was varied from 0 to 1000 rad. The d.c. electrical conductivity of Polyvinyl chloride (PVC) and perspex was measured as a function of temperature ranging from 20°C to 100°C. These samples were irradiated with X-rays of dose 200 rad. The variation of the d.c. conductivity of the treated samples versus temperature was investigated. The results reveal that the d.c. conductivity of LDPE is highly affected by radiation and/or dopant. In addition, the sensitivity of the explored polymers to X-ray irradiation is strongly dependent on its chemical nature.

Nanocalorimeter platform for in situ specific heat measurements and x-ray diffraction at low temperature

NASA Astrophysics Data System (ADS)

Willa, K.; Diao, Z.; Campanini, D.; Welp, U.; Divan, R.; Hudl, M.; Islam, Z.; Kwok, W.-K.; Rydh, A.

2017-12-01

Recent advances in electronics and nanofabrication have enabled membrane-based nanocalorimetry for measurements of the specific heat of microgram-sized samples. We have integrated a nanocalorimeter platform into a 4.5 T split-pair vertical-field magnet to allow for the simultaneous measurement of the specific heat and x-ray scattering in magnetic fields and at temperatures as low as 4 K. This multi-modal approach empowers researchers to directly correlate scattering experiments with insights from thermodynamic properties including structural, electronic, orbital, and magnetic phase transitions. The use of a nanocalorimeter sample platform enables numerous technical advantages: precise measurement and control of the sample temperature, quantification of beam heating effects, fast and precise positioning of the sample in the x-ray beam, and fast acquisition of x-ray scans over a wide temperature range without the need for time-consuming re-centering and re-alignment. Furthermore, on an YBa2Cu3O7-δ crystal and a copper foil, we demonstrate a novel approach to x-ray absorption spectroscopy by monitoring the change in sample temperature as a function of incident photon energy. Finally, we illustrate the new insights that can be gained from in situ structural and thermodynamic measurements by investigating the superheated state occurring at the first-order magneto-elastic phase transition of Fe2P, a material that is of interest for magnetocaloric applications.

Optimization of niobium tunnel junctions as X-ray detectors

NASA Technical Reports Server (NTRS)

Saulnier, Gregory G.; Zacher, Robert A.; Van Vechten, Deborah; Boyer, Craig; Lovellette, Michael N.; Fritz, Gilbert G.; Soulen, Robert J.; Kang, Joonhee; Blamire, Mark; Kirk, Eugenie C. G.

1992-01-01

We report on our ongoing work using Nb/Al/AlO(x)/Nb junctions for the detection of X-rays. Detectors based on superconducting tunneling junctions offer the prospect of resolution over an order of magnitude higher than is obtainable with the current generation of semiconductor-based detectors. Results of measurements taken at 1.85 K (a temperature achievable with current space flight technology) include the current-voltage (I-V) curve, subgap current vs temperature, the dependence of the superconducting current on the applied magnetic field (Fraunhofer pattern), X-ray pulses, and the spectra from a 6 keV X-ray source which gave an intrinsic device resolution of approximately 700 eV. The collection of more than 10 exp 5 electrons per 6 keV photon is established.

Effect of Nano-TiC Dispersed Particles and Electro-Codeposition Parameters on Morphology and Structure of Hybrid Ni/TiC Nanocomposite Layers

PubMed Central

Benea, Lidia; Celis, Jean-Pierre

2016-01-01

This research work describes the effect of dispersed titanium carbide (TiC) nanoparticles into nickel plating bath on Ni/TiC nanostructured composite layers obtained by electro-codeposition. The surface morphology of Ni/TiC nanostructured composite layers was characterized by scanning electron microscopy (SEM). The composition of coatings and the incorporation percentage of TiC nanoparticles into Ni matrix were studied and estimated by using energy dispersive X-ray analysis (EDX). X-ray diffractometer (XRD) has been applied in order to investigate the phase structure as well as the corresponding relative texture coefficients of the composite layers. The results show that the concentration of nano-TiC particles added in the nickel electrolyte affects the inclusion percentage of TiC into Ni/TiC nano strucured layers, as well as the corresponding morphology, relative texture coefficients and thickness indicating an increasing tendency with the increasing concentration of nano-TiC concentration. By increasing the amount of TiC nanoparticles in the electrolyte, their incorporation into nickel matrix also increases. The hybrid Ni/nano-TiC composite layers obtained revealed a higher roughness and higher hardness; therefore, these layers are promising superhydrophobic surfaces for special application and could be more resistant to wear than the pure Ni layers. PMID:28773395

Multiaxial constitutive behavior of an interstitial-free steel: Measurements through X-ray and digital image correlation

PubMed Central

Jeong, Y.; Iadicola, M.A.; Gnäupel-Herold, T.; Creuziger, A.

2017-01-01

Constitutive behaviors of an interstitial-free steel sample were measured using an augmented Marciniak experiment. In these tests, multiaxial strain field data of the flat specimens were measured by the digital image correlation technique. In addition, the flow stress was measured using an X-ray diffractometer. The flat specimens in three different geometries were tested in order to achieve 1) balanced biaxial strain, and plane strain tests with zero strain in either 2) rolling direction or 3) transverse direction. The multiaxial stress and strain data were processed to obtain plastic work contours with reference to a uniaxial tension test along the rolling direction. The experimental results show that the mechanical behavior of the subjected specimen deviates significantly from isotropic behavior predicted by the von Mises yield criterion. The initial yield loci measured by a Marciniak tester is in good agreement with what is predicted by Hill's yield criterion. However, as deformation increases beyond the vonMises strain of 0.05, the shape of the work contour significantly deviates from that of Hill's yield locus. A prediction made by a viscoplastic self-consistent model is in better agreement with the experimental observation than the Hill yield locus with the isotropic work-hardening rule. However, none of the studied models matched the initial or evolving anisotropic behaviors of the interstitial-free steel measured by the augmented Marciniak experiment. PMID:28690400

Synthesis of one-dimensional gold nanostructures and the electrochemical application of the nanohybrid containing functionalized graphene oxide for cholesterol biosensing.

PubMed

Nandini, Seetharamaiah; Nalini, Seetharamaiah; Reddy, M B Madhusudana; Suresh, Gurukar Shivappa; Melo, Jose Savio; Niranjana, Pathappa; Sanetuntikul, Jakkid; Shanmugam, Sangaraju

2016-08-01

This manuscript reports a new approach for the synthesis of one dimensional gold nanostructure (AuNs) and its application in the development of cholesterol biosensor. Au nanostructures have been synthesized by exploiting β-diphenylalanine (β-FF) as an sacrificial template, whereas the Au nanoparticles (AuNPs) were synthesized by ultrasound irradiation. X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy dispersive analysis of X-rays (EDAX) have been employed to characterize the morphology and composition of the prepared samples. With the aim to develop a highly sensitive cholesterol biosensor, cholesterol oxidase (ChOx) was immobilized on AuNs which were appended on the graphite (Gr) electrode via chemisorption onto thiol-functionalized graphene oxide (GO-SH). This Gr/GO-SH/AuNs/ChOx biosensor has been characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy and chronoamperometry. CV results indicated a direct electron transfer between the enzyme and the electrode surface. A new potentiostat intermitant titration technique (PITT) has been studied to determine the diffusion coefficient and maxima potential value. The proposed biosensor showed rapid response, high sensitivity, wide linear range and low detection limit. Furthermore, our AuNs modified electrode showed excellent selectivity, repeatability, reproducibility and long term stability. The proposed electrode has also been used successfully to determine cholesterol in serum samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Earth, soil and environmental science research facility at sector 13 of the Advanced Photon Source. II. Scientific program and experimental instrumentation (abstract)

NASA Astrophysics Data System (ADS)

Sutton, S.; Eng., P. J.; Jaski, Y. R.; Lazaraz, N.; Pluth, J.; Murray, P.; Rarback, H.; Rivers, M.

1996-09-01

The GSECARS (APS sector 13) scientific program will provide fundamental new information on the deep structure and composition of the Earth and other planets, the formation of economic mineral deposits, the cycles and fate of toxic metals in the environment, and the mechanisms of nutrient uptake and disease in plants. In the four experimental stations (2 per beamline), scientists will have access to three main x-ray techniques: diffraction (microcrystal, powder, diamond anvil cell, and large volume press), fluorescence microprobe, and spectroscopy (conventional, microbeam, liquid and solid surfaces). The high pressure facilities will be capable of x-ray crystallography at P≳360 GPa and T˜6000 K with the diamond anvil cell and P˜25 GPa and T˜2500 °C with the large volume press. Diffractometers will allow study of 1 micrometer crystals and micro-powders. The microprobe (1 micrometer focused beam) will be capable of chemical analyses in the sub-ppm range using wavelength and energy dispersive detectors. Spectroscopy instrumentation will be available for XANES and EXAFS with microbeams as well as high sensitivity conventional XAS and studies of liquid and solid interfaces. Visiting scientists will be able to setup, calibrate, and test experiments in off-line laboratories with equipment such as micromanipulators, optical microscopes, clean bench, glove boxes, high powered optical and Raman spectrometers.

Toward a durable superhydrophobic aluminum surface by etching and ZnO nanoparticle deposition.

PubMed

Rezayi, Toktam; Entezari, Mohammad H

2016-02-01

Fabrication of suitable roughness is a fundamental step for acquiring superhydrophobic surfaces. For this purpose, a deposition of ZnO nanoparticles on Al surface was carried out by simple immersion and ultrasound approaches. Then, surface energy reduction was performed using stearic acid (STA) ethanol solution for both methods. The results demonstrated that ultrasound would lead to more stable superhydrophobic Al surfaces (STA-ZnO-Al-U) in comparison with simple immersion method (STA-ZnO-Al-I). Besides, etching in HCl solution in another sample was carried out before ZnO deposition for acquiring more mechanically stable superhydrophobic surface. The potentiodynamic measurements demonstrate that etching in HCl solution under ultrasound leads to superhydrophobic surface (STA-ZnO-Al(E)-U). This sample shows remarkable decrease in corrosion current density (icorr) and long-term stability improvement versus immersion in NaCl solution (3.5%) in comparison with the sample prepared without etching (STA-ZnO-Al-U). Scanning electron micrograph (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed a more condense and further particle deposition on Al substrate when ultrasound was applied in the system. The crystallite evaluation of deposited ZnO nanoparticles was carried out using X-ray diffractometer (XRD). Finally, for STA grafting verification on Al surface, Fourier transform infrared in conjunction with attenuated total reflection (FTIR-ATR) was used as a proper technique. Copyright © 2015 Elsevier Inc. All rights reserved.

Biosynthesis of titanium dioxide nanoparticles using Bacillus amyloliquefaciens culture and enhancement of its photocatalytic activity for the degradation of a sulfonated textile dye Reactive Red 31.

PubMed

Khan, Razia; Fulekar, M H

2016-08-01

The present study aims at exploiting Bacillus amyloliquefaciens for the biosynthesis of titanium dioxide nanoparticles and also investigates role of bacterial enzymes in the biosynthesis of titanium dioxide nanoparticles. Bacterial synthesized as well as metal doped titanium dioxide nanoparticles were characterized by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), Energy dispersive X-ray spectroscopy (EDAX). Amylase activity (43.37IU) in culture supernatant evinced a potential involvement of extracellular enzyme in TiO2 nanoparticle biosynthesis. Crystallite size of bio-synthesized nanoparticles was found to be in the range of 15.23-87.6nm. FTIR spectroscopy and native-PAGE (Polyacrylamide Gel Electrophoresis) clearly indicated involvement of alpha amylase in biosynthesis of TiO2 nanoparticles and in their stabilization. TEM micrographs of the synthesized titanium dioxide nanoparticles revealed the formation of spherical nanoparticles with a size range of 22.11-97.28nm. Photocatalytic degradation of Reactive Red 31 (RR31) dye was carried out using bio-synthesized TiO2 nanoparticles under UV radiation. Photocatalytic activity of synthesized nanoparticles was enhanced by Ag, La, Zn and Pt doping. Platinum doped TiO2 showed highest potential (90.98%) in RR31 degradation as compared to undoped (75.83%). Copyright © 2016 Elsevier Inc. All rights reserved.

Osteoinductive silk fibroin/titanium dioxide/hydroxyapatite hybrid scaffold for bone tissue engineering.

PubMed

Kim, Jung-Ho; Kim, Dong-Kyu; Lee, Ok Joo; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Lee, Jun Ho; Park, Chan Hum

2016-01-01

The present study demonstrated the fabrication that incorporation of titanium isopropoxide (TiO2) and hydroxyapatite (HA) nanoparticles into the silk fibroin (SF) scaffolds. In this process, we prepared TiO2 nanoparticles using sol-gel synthesis and the porous structure was developed by salt-leaching process. Homogeneous distribution of TiO2 and HA nanoparticles were confirmed by images of VP-FE-SEM and those equipped with energy dispersive X-ray spectrometer. Structural characteristics of the porous SF/TiO2/HA hybrid scaffold were also determined using FTIR analysis and X-ray diffractometer. In this study, the porous SF/TiO2/HA hybrid scaffold showed similar porosity, enhanced mechanical property, but decreased water binding abilities, compared with the porous SF scaffold. For evaluation of the osteogenic differentiation of rat bone marrow mesenchymal stem cells, alkaline phosphatase activity and osteogenic gene expression were employed. Our results revealed that the porous SF/TiO2/HA hybrid scaffold had improved osteoinductivity compared with the porous SF scaffold. These results suggest that the osteogenic property as well as mechanical property of the porous SF/TiO2/HA hybrid scaffold could be better than the porous SF scaffold. Therefore, the porous SF/TiO2/HA hybrid scaffold may be a good promising biomaterial for bone tissue engineering application. Copyright © 2015 Elsevier B.V. All rights reserved.

Cu(II), Co(II) and Ni(II) complexes of new Schiff base ligand: Synthesis, thermal and spectroscopic characterizations

NASA Astrophysics Data System (ADS)

Refat, Moamen S.; El-Sayed, Mohamed Y.; Adam, Abdel Majid A.

2013-04-01

Cu(II), Co(II), and Ni(II) complexes were synthesized from 2-[(5-o-chlorophenylazo-2-hydroxybenzylidin)amino]-phenol Schiff base (H2L). Metal ions coordinate in a tetradentate or hexadentate features with these O2N donor ligand, which are characterized by elemental analyses, magnetic moments, infrared, Raman laser, electronic, and 1H NMR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Reactions with Cu(II), Co(II) and Ni(II), resulted [Cu(H2L)(H2O)2(Cl)]Cl, [Co(H2L)(H2O)3]Cl2ṡ3H2O and [Ni(H2L)(H2O)2]Cl2ṡ6H2O. The thermal decomposition behavior of H2L complexes has been investigated by thermogravimetric analysis (TG/DTG) at a heating rate of 10 °C min-1 under nitrogen atmosphere. The brightness side in this study is to take advantage for the preparation and characterizations of single phases of CuO, CoO and NiO nanoparticles using H2L complexes as precursors via a solid-state decomposition procedure. The crystalline structures of products using X-ray diffractometer (XRD), morphology of particles by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) were investigated.

Multiaxial constitutive behavior of an interstitial-free steel: Measurements through X-ray and digital image correlation.

PubMed

Jeong, Y; Iadicola, M A; Gnäupel-Herold, T; Creuziger, A

2016-06-15

Constitutive behaviors of an interstitial-free steel sample were measured using an augmented Marciniak experiment. In these tests, multiaxial strain field data of the flat specimens were measured by the digital image correlation technique. In addition, the flow stress was measured using an X-ray diffractometer. The flat specimens in three different geometries were tested in order to achieve 1) balanced biaxial strain, and plane strain tests with zero strain in either 2) rolling direction or 3) transverse direction. The multiaxial stress and strain data were processed to obtain plastic work contours with reference to a uniaxial tension test along the rolling direction. The experimental results show that the mechanical behavior of the subjected specimen deviates significantly from isotropic behavior predicted by the von Mises yield criterion. The initial yield loci measured by a Marciniak tester is in good agreement with what is predicted by Hill's yield criterion. However, as deformation increases beyond the vonMises strain of 0.05, the shape of the work contour significantly deviates from that of Hill's yield locus. A prediction made by a viscoplastic self-consistent model is in better agreement with the experimental observation than the Hill yield locus with the isotropic work-hardening rule. However, none of the studied models matched the initial or evolving anisotropic behaviors of the interstitial-free steel measured by the augmented Marciniak experiment.

Effects of laser remelting on microstructures and immersion corrosion performance of arc sprayed Al coating in 3.5% NaCl solution

NASA Astrophysics Data System (ADS)

Sun, Ze; Zhang, Donghui; Yan, Baoxu; Kong, Dejun

2018-02-01

An arc sprayed aluminum (Al) coating on S355 steel was processed using a laser remelting (LR). The microstructures, chemical element composition, and phases of the obtained Al coating were analyzed using a field mission scanning electronic microscope (FESEM), energy dispersive spectrometer (EDS), and X-ray diffractometer (XRD), respectively, and the residual stresses were measured using an X-ray diffraction stress tester. The immersion corrosion tests and potentiodynamic polarization of Al coating in 3.5% NaCl solution were performed to investigate the effects of LR on its immersion corrosion behaviors, and the corrosion mechanism of Al coating was also discussed. The results show that the arc sprayed Al coating is composed of Al phase, while that by LR is composed of Al-Fe and AlO4FeO6 phases, and the porosities and cracks in the arc sprayed Al coating are eliminated by LR, The residual stress of arc sprayed Al coating is -5.6 ± 18 MPa, while that after LR is 137.9 ± 12 MPa, which deduces the immersion corrosion resistance of Al coating. The corrosion mechanism of arc sprayed Al coating is pitting corrosion and crevice corrosion, while that by LR is uniform corrosion and pitting corrosion. The corrosion potential of arc sprayed Al coating by LR shifts positively, which improves its immersion corrosion resistance.

Corrosion effect of microorganisms and their metabolite on cement mortar lined pipelines in reclaimed water distribution systems

NASA Astrophysics Data System (ADS)

Yang, Fan; Chen, Minning

2018-06-01

The reclaimed water containing high salinity, great amounts of organic matters and high nutrients can easily lead to growth of biofilms in reclaimed water distribution systems (RWDSs). The microbes colonize the cement surface and microbial metabolites can cause cement biodeterioration. To understand the effect of microbial involvement in the degradation, this study investigated the transformation characteristics of cement-mortar lining and microbial biomass in the simulated RWDS for 1 year by X-ray diffractometer (XRD), X-Ray Fluorescenc (XRF), Heterophic bacteria count (HPC) and DAPI staining. Microbial metabolites were analyzed by GC/MS. The result shows that the carbonation reaction took place in the surface of the eroded cement-mortar lining where the content of CaCO3 was continuously increasing while the content of hydrated compounds were decreasing. The depositing layer of CaSO4·2H2O, CaAl2Si2O8·4H2O and Mg4Al2(OH)14·3H2O on the lining surface were formed by minerals such as Ca, Si, Al and Mg lost from the degraded hydrated compounds. Microbial biomass in the RWDS has maintained an increasing trend during the study. The main microbial metabolites of the biofilm on the cement surface are fatty acids, amino acids, and carbohydrate.

Enhanced Adsorption of Selenium Ions from Aqueous Solution Using Iron Oxide Impregnated Carbon Nanotubes

PubMed Central

Bakather, Omer Y.; Khraisheh, Majeda; Nasser, Mustafa S.

2017-01-01

The aim of this research was to investigate the potential of raw and iron oxide impregnated carbon nanotubes (CNTs) as adsorbents for the removal of selenium (Se) ions from wastewater. The original and modified CNTs with different loadings of Fe2O3 nanoparticles were characterized using high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffractometer (XRD), Brunauer, Emmett, and Teller (BET) surface area analyzer, thermogravimetric analysis (TGA), zeta potential, and energy dispersive X-ray spectroscopy (EDS). The adsorption parameters of the selenium ions from water using raw CNTs and iron oxide impregnated carbon nanotubes (CNT-Fe2O3) were optimized. Total removal of 1 ppm Se ions from water was achieved when 25 mg of CNTs impregnated with 20 wt.% of iron oxide nanoparticles is used. Freundlich and Langmuir isotherm models were used to study the nature of the adsorption process. Pseudo-first and pseudo-second-order models were employed to study the kinetics of selenium ions adsorption onto the surface of iron oxide impregnated CNTs. Maximum adsorption capacity of the Fe2O3 impregnated CNTs, predicted by Langmuir isotherm model, was found to be 111 mg/g. This new finding might revolutionize the adsorption treatment process and application by introducing a new type of nanoadsorbent that has super adsorption capacity towards Se ions. PMID:28555093

Microstructure control of SOFC cathode material: The role of dispersing agent

NASA Astrophysics Data System (ADS)

Ismail, Ismariza; Jani, Abdul Mutalib Md; Osman, Nafisah

2017-09-01

In the present works, La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode powders were synthesized by a sol-gel method with the aid of ethylene glycol which served as the dispersing agent. The phase formation and morphology of the powders were examined by X-Ray diffractometer (XRD) and field emission scanning electron microscopy (FESEM), respectively. The electrochemical properties of the synthesized cathode were obtained using an electrochemical impedance spectroscopy (EIS). The characteristic peaks for LSCF phase appears in the X-ray diffractogram after calcined at 500 °C and complete formation of LSCF single phase was attained at 700 °C. FESEM micrographs showed the presence of spherical particles of the powders with approximate particle size between 10 to 60 nm along with agglomerate morphologies. Well dispersed particles and fewer aggregates were observed for samples prepared with addition of ethylene glycol as the synthesizing aid. The surface area obtained for powder sample prepared with the aid of dispersing agent is 12.0 m2g-1. The EIS measurement results depicts a lower area specific resistance (ASR) obtained for sample prepared with addition of the ethylene glycol as compared to the pristine sample. The present results encourage the optimization of the cathode particle design in order to further improve the cathode performance.

Effects of phosphates on microstructure and bioactivity of micro-arc oxidized calcium phosphate coatings on Mg-Zn-Zr magnesium alloy.

PubMed

Pan, Y K; Chen, C Z; Wang, D G; Zhao, T G

2013-09-01

Calcium phosphate (CaP) coatings were prepared on Mg-Zn-Zr magnesium alloy by micro-arc oxidation (MAO) in electrolyte containing calcium acetate monohydrate (CH3COO)2Ca·H2O) and different phosphates (i.e. disodium hydrogen phosphate dodecahydrate (Na2HPO4·12H2O), sodium phosphate (Na3PO4·H2O) and sodium hexametaphosphate((NaPO3)6)). Scanning electron microscope (SEM), energy-dispersive X-ray spectrometry (EDS) and X-ray diffractometer (XRD) were employed to characterize the microstructure, elemental distribution and phase composition of the CaP coatings. Simulated body fluid (SBF) immersion test was used to evaluate the coating bioactivity and degradability. Systemic toxicity test was used to evaluate the coating biocompatibility. Fluoride ion selective electrode (ISE) was used to measure F(-) ions concentration during 30 days SBF immersion. The CaP coatings effectively reduced the corrosion rate and the surfaces of CaP coatings were covered by a new layer formed of numerous needle-like and scale-like apatites. The formation of these calcium phosphate apatites indicates that the coatings have excellent bioactivity. The coatings formed in (NaPO3)6-containging electrolyte exhibit thicker thickness, higher adhesive strength, slower degradation rate, better apatite-inducing ability and biocompatibility. Copyright © 2013 Elsevier B.V. All rights reserved.

X-rays from the colliding wind binary WR 146

NASA Astrophysics Data System (ADS)

Zhekov, Svetozar A.

2017-12-01

The X-ray emission from the massive Wolf-Rayet binary (WR 146 ) is analysed in the framework of the colliding stellar wind (CSW) picture. The theoretical CSW model spectra match well the shape of the observed X-ray spectrum of WR 146, but they overestimate considerably the observed X-ray flux (emission measure). This is valid in the case of both complete temperature equalization and partial electron heating at the shock fronts (different electron and ion temperatures), but there are indications for a better correspondence between model predictions and observations for the latter. To reconcile the model predictions and observations, the mass-loss rate of WR 146 must be reduced by a factor of 8-10 compared to the currently accepted value for this object (the latter already takes clumping into account). No excess X-ray absorption is derived from the CSW modelling.

A 4 Tesla Superconducting Magnet Developed for a 6 Circle Huber Diffractometer at the XMaS Beamline

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

Thompson, P. B. J.; Brown, S. D.; Bouchenoire, L.

2007-01-19

We report here on the development and testing of a 4 Tesla cryogen free superconducting magnet designed to fit within the Euler cradle of a 6 circle Huber diffractometer, allowing scattering in both the vertical and horizontal planes. The geometry of this magnet allows the field to be applied in three orientations. The first being along the beam direction, the second with the field transverse to the beam direction a horizontal plane and finally the field can be applied vertically with respect to the beam. The magnet has a warm bore and an open geometry of 180 deg. , allowingmore » large access to reciprocal space. A variable temperature insert has been developed, which is capable of working down to a temperature of 1.7 K and operating over a wide range of angles whilst maintaining a temperature stability of a few mK. Initial ferromagnetic diffraction measurements have been carried out on single crystal Tb and Dy samples.« less

Surface layering and melting in an ionic liquid studied by resonant soft X-ray reflectivity

PubMed Central

Mezger, Markus; Ocko, Benjamin M.; Reichert, Harald; Deutsch, Moshe

2013-01-01

The molecular-scale structure of the ionic liquid [C18mim]+[FAP]− near its free surface was studied by complementary methods. X-ray absorption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface layering. Element-specific interfacial profiles were extracted with submolecular resolution from energy-dependent soft X-ray reflectivity data. Temperature-dependent hard X-ray reflectivity, small- and wide-angle X-ray scattering, and infrared spectroscopy uncovered an intriguing melting mechanism for the layered region, where alkyl chain melting drove a negative thermal expansion of the surface layer spacing. PMID:23431181

X-ray emission from high temperature plasmas

NASA Technical Reports Server (NTRS)

Harries, W. L.

1974-01-01

X-rays from a 25-hJ plasma focus apparatus were observed with pinhole cameras. The cameras consist of 0.4 mm diameter pinholes in 2 cm thick lead housing enclosing an X-ray intensifying screen at the image plane. Pictures recorded through thin aluminum foils or plastic sheets for X-ray energies sub gamma smaller than 15 keV show distributed X-ray emissions from the focussed plasma and from the anode surface. However, when thick absorbers are used, radial filamentary structure in the X-ray emission from the anode surface is revealed. Occasionally larger structures are observed in addition to the filaments. Possible mechanisms for the filamentary structure are discussed.

Formation of silicides in annealed periodic multilayers

NASA Astrophysics Data System (ADS)

Maury, H.; Jonnard, P.; Le Guen, K.; André, J.-M.

2009-05-01

Periodic multilayers of nanometric period are widely used as optical components for the X-ray and extreme UV (EUV) ranges, in X-ray space telescopes, X-ray microscopes, EUV photolithography or synchrotron beamlines for example. Their optical performances depend on the quality of the interfaces between the various layers: chemical interdiffusion or mechanical roughness shifts the application wavelength and can drastically decrease the reflectance. Since under high thermal charge interdiffusion is known to get enhanced, the study of the thermal stability of such structures is essential to understand how interfacial compounds develop. We have characterized X-ray and EUV siliconcontaining multilayers (Mo/Si, Sc/Si and Mg/SiC) as a function of the annealing temperature (up to 600°C) using two non-destructive methods. X-ray emission from the silicon atoms, describing the Si valence states, is used to determine the chemical nature of the compounds present in the interphases while X-ray reflectivity in the hard and soft X-ray ranges can be related to the optical properties. In the three cases, interfacial metallic (Mo, Sc, Mg) silicides are evidenced and the thickness of the interphase increases with the annealing temperature. For Mo/Si and Sc/Si multilayers, silicides are even present in the as-prepared multilayers. Characteristic parameters of the stacks are determined: composition of the interphases, thickness and roughness of the layers and interphases if any. Finally, we have evidenced the maximum temperature of application of these multilayers to minimize interdiffusion.

Skylab ATM/S-056 X-ray event analyzer: Instrument description, parameter determination, and analysis example (15 June 1973 1B/M3 flare)

NASA Technical Reports Server (NTRS)

Wilson, R. M.

1976-01-01

The Skylab ATM/S-056 X-Ray Event Analyzer, part of an X-ray telescope experiment, is described. The techniques employed in the analysis of its data to determine electron temperatures and emission measures are reviewed. The analysis of a sample event - the 15 June 1973 1B/M3 flare - is performed. Comparison of the X-Ray Event Analyzer data with that of the SolRad 9 observations indicates that the X-Ray Event Analyzer accurately monitored the sun's 2.5 to 7.25 A X-ray emission and to a lesser extent the 6.1 to 20 A emission. A mean average peak temperature of 15 million K at 1,412 UT and a mean average peak electron density (assuming a flare volume of 10 to the 13 power cu km) of 27 million/cu mm at 1,416 to 1,417 UT are deduced for the event. The X-Ray Event Analyzer data, having a 2.5 s time resolution, should be invaluable in comparisons with other high-time resolution data (e.g., radio bursts).

POWTEX Neutron Diffractometer at FRM II - New Perspectives in Rock Deformation and Recrystallisation Analysis

NASA Astrophysics Data System (ADS)

Walter, J. M.; Stipp, M.; Ullemeyer, K.; Klein, H.; Leiss, B.; Hansen, B.; Kuhs, W. F.

2011-12-01

Neutron diffraction has become a routine method in Geoscience for the quantitative analysis of crystallographic preferred orientations (CPOs) and for (experimental) powder diffraction. Quantitative texture analysis is a common tool for the investigation of fabric development in mono- and polyphase rocks, their deformation histories and kinematics. Furthermore the quantitative characterization of anisotropic physical properties by bulk texture measurements can be achieved due to the high penetration capabilities of neutrons. To cope with increasing needs for beam time at neutron diffraction facilities with the corresponding technical characteristics and equipment, POWTEX (POWder and TEXture Diffractometer) is designed as a high-intensity diffractometer at the neutron research reactor FRM II in Garching, Germany by groups from the RWTH Aachen, Forschungszentrum Jülich and the University of Göttingen. Complementary to existing neutron diffractometers (SKAT at Dubna, Russia; GEM at ISIS, UK; HIPPO at Los Alamos, USA; D20 at ILL, France; and the local STRESS-SPEC and SPODI at FRM II) the layout of POWTEX is focused on fast (texture) measurements for either time-resolved experiments or the measurement of larger sample series as necessary for the study of large scale geological structures. By utilizing a range of neutron wavelengths simultaneously (TOF-technique), a high flux (~1 x 107 n/cm2s) and a high detector coverage ( 9.8 sr) effective texture measurements without sample tilting and rotation are possible. Furthermore the instrument and the angular detector resolution is sufficient for strong recrystallisation textures as well as weak textures of polyphase rocks. Thereby large sample environments will be implemented at POWTEX allowing in-situ time-resolved texture measurements during deformation experiments on rocksalt, ice and other materials. Furthermore a furnace for 3D-recrystallisation analysis of single grains will be realized complementary to the furnace that already exists for fine grained materials at the synchrotron beamline BW5 at HASYLAB, Germany (e.g. Klein et al. 2009). The in-situ triaxial deformation apparatus is operated by a uniaxial spindle drive with a maximum axial load of 200 kN, which will be redesigned to minimize shadowing effects on the detector. The HT experiments will be carried out in uniaxial compression or extension and an upgrade to triaxial deformation conditions is envisaged. The load frame can alternatively be used for ice deformation by inserting a cryostat cell for temperatures down to 77 K with a triaxial apparatus allowing also simple shear experiments on ice. Strain rates range between 10-8 and 10-3 s-1 reaching to at least 50 % axial strain. The furnace for the recrystallization analysis will be a mirror furnace with temperatures up to 1500° C, which will be rotatable around a vertical axis to obtain the required stereologic orientation information.

Time-dependent, x-ray spectral unfolds and brightness temperatures for intense Li{sup +} ion beam-driven hohlraums

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

Fehl, D.L.; Chandler, G.A.; Biggs, F.

X-ray-producing hohlraums are being studied as indirect drives for inertial confinement fusion targets. In a 1994 target series on the PBFAII accelerator, cylindrical hohlraum targets were heated by an intense Li{sup +} ion beam and viewed by an array of 13 time-resolved, filtered x-ray detectors (XRDs). The unfold operator (UFO) code and its suite of auxiliary functions were used extensively in obtaining time-resolved x-ray spectra and radiation temperatures from this diagnostic. The UFO was also used to obtain fitted response functions from calibration data, to simulate data from blackbody x-ray spectra of interest, to determine the suitability of various unfoldingmore » parameters (e.g., energy domain, energy partition, smoothing conditions, and basis functions), to interpolate the XRD signal traces, and to unfold experimental data. The simulation capabilities of the code were useful in understanding an anomalous feature in the unfolded spectra at low photon energies ({le}100 eV). Uncertainties in the differential and energy-integrated unfolded spectra were estimated from uncertainties in the data. The time{endash}history of the radiation temperature agreed well with independent calculations of the wall temperature in the hohlraum. {copyright} {ital 1997 American Institute of Physics.}« less

Density gradient free electron collisionally excited x-ray laser

DOEpatents

Campbell, E.M.; Rosen, M.D.

1984-11-29

An operational x-ray laser is provided that amplifies 3p-3s transition x-ray radiation along an approximately linear path. The x-ray laser is driven by a high power optical laser. The driving line focused optical laser beam illuminates a free-standing thin foil that may be associated with a substrate for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the x-ray laser gain medium. The x-ray laser may be driven by more than one optical laser beam. The x-ray laser has been successfully demonstrated to function in a series of experimental tests.

Boundary layers in cataclysmic variables: The HEAO-1 X-ray constraints

NASA Technical Reports Server (NTRS)

Jensen, K. A.

1983-01-01

The predictions of the boundary layer model for the X-ray emission from novae are summarized. A discrepancy between observations and theory in the X-ray observations is found. Constraints on the nature of the boundary layers in novae, based on the lack of detections of novae in the HEAO-1 soft X-ray survey are provided. Temperature and column densities for optically thick boundary layers in novae are estimated.

Temperature Measurements in Compressed and Uncompressed SPECTOR Plasmas at General Fusion

NASA Astrophysics Data System (ADS)

Young, William; Carter, Neil; Howard, Stephen; Carle, Patrick; O'Shea, Peter; Fusion Team, General

2017-10-01

Accurate temperature measurements are critical to establishing the behavior of General Fusion's SPECTOR plasma injector, both before and during compression. As compression tests impose additional constraints on diagnostic access to the plasma, a two-color, filter-based soft x-ray electron temperature diagnostic has been implemented. Ion Doppler spectroscopy measurements also provide impurity ion temperatures on compression tests. The soft x-ray and ion Doppler spectroscopy measurements are being validated against a Thomson scattering system on an uncompressed version of SPECTOR with more diagnostic access. The multipoint Thomson scattering diagnostic also provides up to a six point temperature and density profile, with the density measurements validated against a far infrared interferometer. Temperatures above 300 eV have been demonstrated to be sustained for over 500 microseconds in uncompressed plasmas. Optimization of soft x-ray filters is ongoing, in order to balance blocking of impurity line radiation with signal strength.

The coolest DA white dwarfs detected at soft X-ray wavelengths

NASA Technical Reports Server (NTRS)

Kidder, K. M.; Holberg, J. B.; Barstow, M. A.; Tweedy, R. W.; Wesemael, F.

1992-01-01

New soft X-ray/EUV photometric observations of the DA white dwarfs KPD 0631 + 1043 = WD 0631 + 107 and PG 1113 + 413 = WD 1113 + 413 are analyzed. Previously reported soft X-ray detections of three other DAs and the failure to detect a fourth DA in deep Exosat observations are investigated. New ground-based spectra are presented for all of the objects, with IUE Ly-alpha spectra for some. These data are used to constrain the effective temperatures and surface gravities. The improved estimates of these parameters are employed to refer a photospheric He abundance for the hotter objects and to elucidate an effective observational low-temperature threshold for the detection of pure hydrogen DA white dwarfs at soft X-ray wavelengths.

Temperature dependence of commercial 4H-SiC UV Schottky photodiodes for X-ray detection and spectroscopy

NASA Astrophysics Data System (ADS)

Zhao, S.; Lioliou, G.; Barnett, A. M.

2017-07-01

Two commercial-off-the-shelf (COTS) 4H-SiC UV photodiodes have been investigated for their suitability as low-cost high temperature tolerant X-ray detectors. Electrical characterisation of the photodiodes which had different active areas (0.06 mm2 and 0.5 mm2) is reported over the temperature range 0 °C to 140 °C together with measurements of the X-ray photocurrents generated when the detectors were illuminated with an 55Fe radioisotope X-ray source. The 0.06 mm2 photodiode was also investigated as a photon counting spectroscopic X-ray detector across the temperature range 0 °C to 100 °C. The depletion widths (at 120 V reverse bias) of the two diodes were found to be 2.3 μm and 4.5 μm, for the 0.06 mm2 and 0.5 mm2 detectors respectively, at 140 °C. Both devices had low leakage currents (<10 pA) at temperatures ≤40 °C even at high electric field strengths (500 kV/cm for 0.06 mm2 diode; 267 kV/cm for 0.5 mm2 diode). At 140 °C and similar field strengths (514 kV/cm for 0.06 mm2 diode; 269 kV/cm for 0.5 mm2 diode), the leakage currents of both diodes were <2 nA (corresponding to leakage current densities of 2.4 μA/cm2 and 0.3 μA/cm2 for each diode respectively). The results demonstrated that both devices could function as current mode detectors of soft X-rays at the temperatures <80 °C and that when coupled to a low noise charge sensitive preamplifier, the smaller diode functioned as a photon counting spectroscopic X-ray detector at temperatures ≤100 °C with modest energy resolution (1.6 keV FWHM at 5.9 keV at 0 °C; 2.6 keV FWHM at 5.9 keV at 100 °C). Due to their temperature tolerance, wide commercial availability, and the radiation hardness of SiC, such detectors are expected to find utility in future low-cost nanosatellite (cubesat) missions and cost-sensitive industrial applications.

THE CHANDRA PLANETARY NEBULA SURVEY (ChanPlaNS). III. X-RAY EMISSION FROM THE CENTRAL STARS OF PLANETARY NEBULAE

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

Montez, R. Jr.; Kastner, J. H.; Freeman, M.

2015-02-10

We present X-ray spectral analysis of 20 point-like X-ray sources detected in Chandra Planetary Nebula Survey observations of 59 planetary nebulae (PNe) in the solar neighborhood. Most of these 20 detections are associated with luminous central stars within relatively young, compact nebulae. The vast majority of these point-like X-ray-emitting sources at PN cores display relatively ''hard'' (≥0.5 keV) X-ray emission components that are unlikely to be due to photospheric emission from the hot central stars (CSPN). Instead, we demonstrate that these sources are well modeled by optically thin thermal plasmas. From the plasma properties, we identify two classes of CSPN X-raymore » emission: (1) high-temperature plasmas with X-ray luminosities, L {sub X}, that appear uncorrelated with the CSPN bolometric luminosity, L {sub bol} and (2) lower-temperature plasmas with L {sub X}/L {sub bol} ∼ 10{sup –7}. We suggest these two classes correspond to the physical processes of magnetically active binary companions and self-shocking stellar winds, respectively. In many cases this conclusion is supported by corroborative multiwavelength evidence for the wind and binary properties of the PN central stars. By thus honing in on the origins of X-ray emission from PN central stars, we enhance the ability of CSPN X-ray sources to constrain models of PN shaping that invoke wind interactions and binarity.« less

Study of CT Scan Flooding System at High Temperature and Pressure

NASA Astrophysics Data System (ADS)

Chen, X. Y.

2017-12-01

CT scan flooding experiment can scan micro-pore in different flooding stages by the use of CT scan technology, without changing the external morphology and internal structure of the core, and observe the distribution characterization in pore medium of different flooding fluid under different pressure.thus,it can rebuilt the distribution images of oil-water distribution in different flooding stages. However,under extreme high pressure and temperature conditions,the CT scan system can not meet the requirements. Container of low density materials or thin shell can not resist high pressure,while high density materials or thick shell will cause attenuation and scattering of X-ray. The experiment uses a simple Ct scanning systems.X ray from a point light source passing trough a micro beryllium shell on High pressure stainless steal container,continuously irradiates the core holder that can continuously 360° rotate along the core axis. A rare earth intensifying screen behind the core holder emitting light when irradiated with X ray can show the core X ray section image. An optical camera record the core X ray images through a transparency high pressure glazing that placed on the High pressure stainless steal container.Thus,multiple core X ray section images can reconstruct the 3D core reconstruction after a series of data processing.The experiment shows that both the micro beryllium shell and rare earth intensifying screen can work in high temperature and high pressure environment in the stainless steal container. This way that X-ray passes through a thin layer of micro beryllium shell , not high pressure stainless steal shell,avoid the attenuation and scattering of X-ray from the container shell,while improving the high-pressure experiment requirements.

Phase degradation in B xGa 1–xN films grown at low temperature by metalorganic vapor phase epitaxy

DOE PAGES

Gunning, Brendan P.; Moseley, Michael W.; Koleske, Daniel D.; ...

2016-11-01

Using metalorganic vapor phase epitaxy, a comprehensive study of B xGa 1-xN growth on GaN and AlN templates is described. BGaN growth at high-temperature and high-pressure results in rough surfaces and poor boron incorporation efficiency, while growth at low-temperature and low-pressure (750–900 °C and 20 Torr) using nitrogen carrier gas results in improved surface morphology and boron incorporation up to ~7.4% as determined by nuclear reaction analysis. However, further structural analysis by transmission electron microscopy and x-ray pole figures points to severe degradation of the high boron composition films, into a twinned cubic structure with a high density of stackingmore » faults and little or no room temperature photoluminescence emission. Films with <1% triethylboron (TEB) flow show more intense, narrower x-ray diffraction peaks, near-band-edge photoluminescence emission at ~362 nm, and primarily wurtzite-phase structure in the x-ray pole figures. For films with >1% TEB flow, the crystal structure becomes dominated by the cubic phase. As a result, only when the TEB flow is zero (pure GaN), does the cubic phase entirely disappear from the x-ray pole figure, suggesting that under these growth conditions even very low boron compositions lead to mixed crystalline phases.« less

Phase degradation in B xGa 1–xN films grown at low temperature by metalorganic vapor phase epitaxy

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

Gunning, Brendan P.; Moseley, Michael W.; Koleske, Daniel D.

Using metalorganic vapor phase epitaxy, a comprehensive study of B xGa 1-xN growth on GaN and AlN templates is described. BGaN growth at high-temperature and high-pressure results in rough surfaces and poor boron incorporation efficiency, while growth at low-temperature and low-pressure (750–900 °C and 20 Torr) using nitrogen carrier gas results in improved surface morphology and boron incorporation up to ~7.4% as determined by nuclear reaction analysis. However, further structural analysis by transmission electron microscopy and x-ray pole figures points to severe degradation of the high boron composition films, into a twinned cubic structure with a high density of stackingmore » faults and little or no room temperature photoluminescence emission. Films with <1% triethylboron (TEB) flow show more intense, narrower x-ray diffraction peaks, near-band-edge photoluminescence emission at ~362 nm, and primarily wurtzite-phase structure in the x-ray pole figures. For films with >1% TEB flow, the crystal structure becomes dominated by the cubic phase. As a result, only when the TEB flow is zero (pure GaN), does the cubic phase entirely disappear from the x-ray pole figure, suggesting that under these growth conditions even very low boron compositions lead to mixed crystalline phases.« less

Low-Cost Structural Thermoelectric Materials: Processing and Consolidation

DTIC Science & Technology

2015-01-01

12 Fig. 8 Hardness from X - ray 2θ profiles for the Fe–Al–V and Ti–Ni–Sn... Hardness from X - ray 2θ profiles for the Fe–Al–V and Ti–Ni–Sn TE materials as a function of annealing temperature 3.3 Consolidated Thermoelectric...9 3. Results 10 3.1 X - ray

Low Dose X-Ray Speckle Visibility Spectroscopy Reveals Nanoscale Dynamics in Radiation Sensitive Ionic Liquids

NASA Astrophysics Data System (ADS)

Verwohlt, Jan; Reiser, Mario; Randolph, Lisa; Matic, Aleksandar; Medina, Luis Aguilera; Madsen, Anders; Sprung, Michael; Zozulya, Alexey; Gutt, Christian

2018-04-01

X-ray radiation damage provides a serious bottleneck for investigating microsecond to second dynamics on nanometer length scales employing x-ray photon correlation spectroscopy. This limitation hinders the investigation of real time dynamics in most soft matter and biological materials which can tolerate only x-ray doses of kGy and below. Here, we show that this bottleneck can be overcome by low dose x-ray speckle visibility spectroscopy. Employing x-ray doses of 22-438 kGy and analyzing the sparse speckle pattern of count rates as low as 6.7 ×10-3 per pixel, we follow the slow nanoscale dynamics of an ionic liquid (IL) at the glass transition. At the prepeak of nanoscale order in the IL, we observe complex dynamics upon approaching the glass transition temperature TG with a freezing in of the alpha relaxation and a multitude of millisecond local relaxations existing well below TG . We identify this fast relaxation as being responsible for the increasing development of nanoscale order observed in ILs at temperatures below TG .

Soft x-ray absorption spectroscopy of metalloproteins and high-valent metal-complexes at room temperature using free-electron lasers

PubMed Central

Kubin, Markus; Kern, Jan; Gul, Sheraz; Kroll, Thomas; Chatterjee, Ruchira; Löchel, Heike; Fuller, Franklin D.; Sierra, Raymond G.; Quevedo, Wilson; Weniger, Christian; Rehanek, Jens; Firsov, Anatoly; Laksmono, Hartawan; Weninger, Clemens; Alonso-Mori, Roberto; Nordlund, Dennis L.; Lassalle-Kaiser, Benedikt; Glownia, James M.; Krzywinski, Jacek; Moeller, Stefan; Turner, Joshua J.; Minitti, Michael P.; Dakovski, Georgi L.; Koroidov, Sergey; Kawde, Anurag; Kanady, Jacob S.; Tsui, Emily Y.; Suseno, Sandy; Han, Zhiji; Hill, Ethan; Taguchi, Taketo; Borovik, Andrew S.; Agapie, Theodor; Messinger, Johannes; Erko, Alexei; Föhlisch, Alexander; Bergmann, Uwe; Mitzner, Rolf; Yachandra, Vittal K.; Yano, Junko; Wernet, Philippe

2017-01-01

X-ray absorption spectroscopy at the L-edge of 3d transition metals provides unique information on the local metal charge and spin states by directly probing 3d-derived molecular orbitals through 2p-3d transitions. However, this soft x-ray technique has been rarely used at synchrotron facilities for mechanistic studies of metalloenzymes due to the difficulties of x-ray-induced sample damage and strong background signals from light elements that can dominate the low metal signal. Here, we combine femtosecond soft x-ray pulses from a free-electron laser with a novel x-ray fluorescence-yield spectrometer to overcome these difficulties. We present L-edge absorption spectra of inorganic high-valent Mn complexes (Mn ∼ 6–15 mmol/l) with no visible effects of radiation damage. We also present the first L-edge absorption spectra of the oxygen evolving complex (Mn4CaO5) in Photosystem II (Mn < 1 mmol/l) at room temperature, measured under similar conditions. Our approach opens new ways to study metalloenzymes under functional conditions. PMID:28944255

Soft x-ray absorption spectroscopy of metalloproteins and high-valent metal-complexes at room temperature using free-electron lasers

DOE PAGES

Kubin, Markus; Kern, Jan; Gul, Sheraz; ...

2017-09-01

X-ray absorption spectroscopy at the L-edge of 3d transition metals provides unique information on the local metal charge and spin states by directly probing 3d-derived molecular orbitals through 2p-3d transitions. But, this soft x-ray technique has been rarely used at synchrotron facilities for mechanistic studies of metalloenzymes due to the difficulties of x-ray-induced sample damage and strong background signals from light elements that can dominate the low metal signal. Here, we combine femtosecond soft x-ray pulses from a free-electron laser with a novel x-ray fluorescence-yield spectrometer to overcome these difficulties. We present L-edge absorption spectra of inorganic high-valent Mn complexesmore » (Mn ~ 6-15 mmol/l) with no visible effects of radiation damage. We then present the first L-edge absorption spectra of the oxygen evolving complex (Mn 4 CaO 5 ) in Photosystem II (Mn < 1 mmol/l) at room temperature, measured under similar conditions. Our approach opens new ways to study metalloenzymes under functional conditions.« less

Radiation of X-Rays Using Uniaxially Polarized LiNbO3 Single Crystal

NASA Astrophysics Data System (ADS)

Fukao, Shinji; Nakanishi, Yoshikazu; Mizoguchi, Tadahiro; Ito, Yoshiaki; Nakamura, Toru; Yoshikado, Shinzo

2009-03-01

X-rays are radiated due to the bremsstrahlung caused by the collision of electrons with a metal target placed opposite the negative electric surface of a crystal by changing the temperature of a LiNbO3 single crystal uniaxially polarized in the c-axis direction. It is suggested that both electric field intensity and electron density determine the intensity of X-ray radiation. Electrons are supplied by the ionization of residual gas in space, field emission from a case inside which a crystal is located, considered to be due to the high electric-field intensity formed by the surface charges on the crystal, and an external electron source, such as a thermionic source. In a high vacuum, it was found that the electrons supplied by electric-field emission mainly contribute to the radiation of X-rays. It was found that the integrated intensity of X-rays can be maximized by supplying electrons both external and by electric-field emission. Furthermore, the integrated intensity of the X-rays is stable for many repeated temperature changes.

ASCA X-ray observations of pre-main-sequence stars

NASA Technical Reports Server (NTRS)

Skinner, S. L.; Walter, F. M.; Yamauchi, S.

1996-01-01

The results of recent Advanced Satellite for Cosmology and Astrophysics (ASCA) X-ray observations of two pre-main sequence stars are presented: the weak emission line T Tauri star HD 142361, and the Herbig Ae star HD 104237. The solid state imaging spectrometer spectra for HD 142361 shows a clear emission line from H-like Mg 7, and spectral fits reveal a multiple temperature plasma with a hot component of at least 16 MK. The spectra of HD 104237 show a complex temperature structure with the hottest plasma at temperatures of greater than 30 MK. It is concluded that mechanisms that predict only soft X-ray emission can be dismissed for Herbig Ae stars.

Coronal temperatures of unusually active K-dwarf binary systems

NASA Technical Reports Server (NTRS)

Stern, Robert A.

1994-01-01

We report the results of a ROSAT pointed study of 4 BY Dra systems. Good quality pulse-height spectra are available from all four systems. Except for a required interstellar absorption component in HD 319139, the four systems have remarkably similar x-ray spectra; the two systems BD +22deg.669 and BD +23deg.635 look virtually identical in x rays. Analysis of the 4 x-ray spectra reveals that, in all cases, a single-temperature hot plasma (RS or Mewe) spectra is inadequate to fit the data, and two temperatures are required. We present examples of fitted pulse-height spectra and chi squared contours in kT(sub 1)-kT(sub 2) space.