Structural properties of alkaline sodium lead fluoride borate glasses incorporated with Praseodymium ion

NASA Astrophysics Data System (ADS)

Lenkennavar, Susheela K.; Madhu, A.; Eraiah, B.; Kokila, M. K.

2018-05-01

The effect of different alkaline and Pr ions on the density and structure of Na2O-PbO-MO-B2O3 (M represents Ba/Ca/Sr) has been investigated using X-ray diffraction (XRD), infrared spectrophotometer (FTIR). The amorphous phase has been identified based on X-ray diffraction analysis. The Praseodymium oxide plays the role as a glass-modifier and influences on BO3↔BO4 conversion. The same effect is also observed in density and molar volume variation due to non bridging oxygen's (NBO) created when BO3 units are converted.

Structural studies on choline-carboxylate bio-ionic liquids by x-ray scattering and molecular dynamics

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

Tanzi, Luana; Ramondo, Fabio, E-mail: fabio.ramondo@univaq.it; Caminiti, Ruggero

2015-09-21

We report a X-ray diffraction and molecular dynamics study on three choline-based bio-ionic liquids, choline formate, [Ch] [For], choline propanoate, [Ch][Pro], and choline butanoate, [Ch][But]. For the first time, this class of ionic liquids has been investigated by X-ray diffraction. Experimental and theoretical structure factors have been compared for each term of the series. Local structural organization has been obtained from ab initio calculations through static models of isolated ion pairs and dynamic simulations of small portions of liquids through twelve, ten, and nine ion pairs for [Ch][For], [Ch][Pro], and [Ch][But], respectively. All the theoretical models indicate that cations andmore » anions are connected by strong hydrogen bonding and form stable ion pairs in the liquid that are reminiscent of the static ab initio ion pairs. Different structural aspects may affect the radial distribution function, like the local structure of ion pairs and the conformation of choline. When small portions of liquids have been simulated by dynamic quantum chemical methods, some key structural features of the X-ray radial distribution function were well reproduced whereas the classical force fields here applied did not entirely reproduce all the observed structural features.« less

Planar techniques for fabricating X-ray diffraction gratings and zone plates

NASA Technical Reports Server (NTRS)

Smith, H. I.; Anderson, E. H.; Hawryluk, A. M.; Schattenburg, M. L.

1984-01-01

The state of current planar techniques in the fabrication of Fresnel zone plates and diffraction gratings is reviewed. Among the fabrication techniques described are multilayer resist techniques; scanning electron beam lithography; and holographic lithography. Consideration is also given to: X-ray lithography; ion beam lithography; and electroplating. SEM photographs of the undercut profiles obtained in a type AZ 135OB photoresistor by holographic lithography are provided.

Uranium-molybdenum nuclear fuel plates behaviour under heavy ion irradiation: An X-ray diffraction analysis

NASA Astrophysics Data System (ADS)

Palancher, H.; Wieschalla, N.; Martin, P.; Tucoulou, R.; Sabathier, C.; Petry, W.; Berar, J.-F.; Valot, C.; Dubois, S.

2009-03-01

Heavy ion irradiation has been proposed for discriminating UMo/Al specimens which are good candidates for research reactor fuels. Two UMo/Al dispersed fuels (U-7 wt%Mo/Al and U-10 wt%Mo/Al) have been irradiated with a 80 MeV 127I beam up to an ion fluence of 2 × 1017 cm-2. Microscopy and mainly X-ray diffraction using large and micrometer sized beams have enabled to characterize the grown interaction layer: UAl3 appears to be the only produced crystallized phase. The presence of an amorphous additional phase can however not be excluded. These results are in good agreement with characterizations performed on in-pile irradiated fuels and encourage new studies with heavy ion irradiation.

Depth profiling of ion-induced damage in D9 alloy using X-ray diffraction

NASA Astrophysics Data System (ADS)

Dey, S.; Gayathri, N.; Mukherjee, P.

2018-04-01

The ion-induced depthwise damage profile in 35 MeV α-irradiated D9 alloy samples with doses of 5 × 1015 He2+/cm2, 6.4 × 1016 He2+/cm2 and 2 × 1017 He2+/cm2 has been assessed using X-ray diffraction technique. The microstructural characterisation has been done along the depth from beyond the stopping region (peak damage region) to the homogeneous damage region (surface) as simulated from SRIM. The parameters such as domain size and microstrain have been evaluated using two different X-ray diffraction line profile analysis techniques. The results indicate that at low dose the damage profile shows a prominent variation as a function of depth but, with increasing dose, it becomes more homogeneous along the depth. This suggests that enhanced defect diffusion and their annihilation in pre-existing and newly formed sinks play a significant role in deciding the final microstructure of the irradiated sample as a function of depth.

Formation of nanostructures in Eu3+ doped glass-ceramics: an XAS study.

PubMed

Pellicer-Porres, J; Segura, A; Martínez-Criado, G; Rodríguez-Mendoza, U R; Lavín, V

2013-01-16

We describe the results of x-ray absorption experiments carried out to deduce structural and chemical information in Eu(3+) doped, transparent, oxyfluoride glass and nanostructured glass-ceramic samples. The spectra were measured at the Pb and Eu-L(III) edges. The Eu environment in the glass samples is observed to be similar to that of EuF(3). Complementary x-ray diffraction experiments show that thermal annealing creates β-PbF(2) type nanocrystals. X-ray absorption indicates that Eu ions act as seeds in the nanocrystal formation. There is evidence of interstitial fluorine atoms around Eu ions as well as Eu dimers. X-ray absorption at the Pb-L(III) edge shows that after the thermal treatment most lead atoms form a PbO amorphous phase and that only 10% of the lead atoms remain available to form β-PbF(2) type nanocrystals. Both x-ray diffraction and absorption point to a high Eu content in the nanocrystals. Our study suggests new approaches to the oxyfluoride glass-ceramic synthesis in order to further improve their properties.

Chemical characterization of 4140 steel implanted by nitrogen ions

NASA Astrophysics Data System (ADS)

Niño, E. D. V.; Pinto, J. L.; Dugar-Zhabon, V.; Henao, J. A.

2012-06-01

AISI SAE 4140 steel samples of different surface roughness which are implanted with 20 keV and 30 keV nitrogen ions at a dose of 1017 ions/cm2 are studied. The crystal phases of nitrogen compositions of the implanted samples, obtained with help of an x-ray diffraction method, are confronted with the data reported by the International Centre for Diffraction Data (ICDD) PDF-2. The implantation treatment is realized in high-voltage pulsed discharges at low pressures. The crystal structure of the implanted solid surfaces is analyzed by the x-ray diffraction technique which permits to identify the possible newly formed compounds and to identify any change in the surface structure of the treated samples. A decrease in the intensity of the plane (110), a reduction of the cell unity in values of 2-theta and a diminishing of the crystallite dimensions in comparison with non-implanted samples are observed.

Combined operando X-ray diffraction-electrochemical impedance spectroscopy detecting solid solution reactions of LiFePO4 in batteries.

PubMed

Hess, Michael; Sasaki, Tsuyoshi; Villevieille, Claire; Novák, Petr

2015-09-08

Lithium-ion batteries are widely used for portable applications today; however, often suffer from limited recharge rates. One reason for such limitation can be a reduced active surface area during phase separation. Here we report a technique combining high-resolution operando synchrotron X-ray diffraction coupled with electrochemical impedance spectroscopy to directly track non-equilibrium intermediate phases in lithium-ion battery materials. LiFePO4, for example, is known to undergo phase separation when cycled under low-current-density conditions. However, operando X-ray diffraction under ultra-high-rate alternating current and direct current excitation reveal a continuous but current-dependent, solid solution reaction between LiFePO4 and FePO4 which is consistent with previous experiments and calculations. In addition, the formation of a preferred phase with a composition similar to the eutectoid composition, Li0.625FePO4, is evident. Even at a low rate of 0.1C, ∼20% of the X-ray diffractogram can be attributed to non-equilibrium phases, which changes our understanding of the intercalation dynamics in LiFePO4.

Modification of the crystal structure of gadolinium gallium garnet by helium ion irradiation

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

Ostafiychuk, B. K.; Yaremiy, I. P., E-mail: yaremiy@rambler.ru; Yaremiy, S. I.

2013-12-15

The structure of gadolinium gallium garnet (GGG) single crystals before and after implantation by He{sup +} ions has been investigated using high-resolution X-ray diffraction methods and the generalized dynamic theory of X-ray scattering. The main types of growth defects in GGG single crystals and radiation-induced defects in the ion-implanted layer have been determined. It is established that the concentration of dislocation loops in the GGG surface layer modified by ion implantation increases and their radius decreases with an increase in the implantation dose.

Crystal structure of pentasodium hydrogen dicitrate from synchrotron X-ray powder diffraction data and DFT comparison

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

Rammohan, Alagappa; Kaduk, James A.

2017-01-27

The crystal structure of pentasodium hydrogen dicitrate, Na 5H(C 6H 5O 7) 2, has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Each of the two independent citrate anions is joined into a dimer by very strong centrosymmetric O—H...O hydrogen bonds, with O...O distances of 2.419 and 2.409 Å. Four octahedrally coordinated Na +ions share edges to form open layers parallel to theabplane. A fifth Na +ion in trigonal–bipyramidal coordination shares faces with NaO 6octahedra on both sides of these layers.

Na0.44MnO2 nanorods as a cathode material for Na-ion batteries

NASA Astrophysics Data System (ADS)

Avci, Sevda; Oz, Erdinc; Demirel, Serkan; Altin, Emine; Altin, Serdar; Bayri, Ali; Yakinci, Eyyuphan

2014-03-01

Lithium-ion batteries have dominated the rechargeable battery market because of their high energy and power capability. On the other hand, sodium is one of the more abundant elements on Earth unlike Li. Moreover, Na has similar chemical properties to Li, indicating that Na-ion batteries can be an alternative to Li counterparts. With that respect, we have synthesized Na0.44MnO2 nanorods as cathode materials for Na-ion batteries. We have investigated the effects of structural, electrical, and magnetic properties on battery performance. We report the synthesis conditions and growth mechanism of the nanorods. The structure and the morphology of the materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and atomic force microscopy (AFM) techniques. Temperature dependent structural changes were determined via in situ X-ray diffraction and TG-DTA measurements showing structural changes above room temperature. This work is funded by The Scientific and Technological Research Council of Turkey with Grant No:112M487.

Electrochemical reactions in fluoride-ion batteries: mechanistic insights from pair distribution function analysis

DOE PAGES

Grenier, Antonin; Porras-Gutierrez, Ana-Gabriela; Groult, Henri; ...

2017-07-05

Detailed analysis of electrochemical reactions occurring in rechargeable Fluoride-Ion Batteries (FIBs) is provided by means of synchrotron X-ray diffraction (XRD) and Pair Distribution Function (PDF) analysis.

Compact ultrahigh vacuum sample environments for x-ray nanobeam diffraction and imaging.

PubMed

Evans, P G; Chahine, G; Grifone, R; Jacques, V L R; Spalenka, J W; Schülli, T U

2013-11-01

X-ray nanobeams present the opportunity to obtain structural insight in materials with small volumes or nanoscale heterogeneity. The effective spatial resolution of the information derived from nanobeam techniques depends on the stability and precision with which the relative position of the x-ray optics and sample can be controlled. Nanobeam techniques include diffraction, imaging, and coherent scattering, with applications throughout materials science and condensed matter physics. Sample positioning is a significant mechanical challenge for x-ray instrumentation providing vacuum or controlled gas environments at elevated temperatures. Such environments often have masses that are too large for nanopositioners capable of the required positional accuracy of the order of a small fraction of the x-ray spot size. Similarly, the need to place x-ray optics as close as 1 cm to the sample places a constraint on the overall size of the sample environment. We illustrate a solution to the mechanical challenge in which compact ion-pumped ultrahigh vacuum chambers with masses of 1-2 kg are integrated with nanopositioners. The overall size of the environment is sufficiently small to allow their use with zone-plate focusing optics. We describe the design of sample environments for elevated-temperature nanobeam diffraction experiments demonstrate in situ diffraction, reflectivity, and scanning nanobeam imaging of the ripening of Au crystallites on Si substrates.

Compact ultrahigh vacuum sample environments for x-ray nanobeam diffraction and imaging

NASA Astrophysics Data System (ADS)

Evans, P. G.; Chahine, G.; Grifone, R.; Jacques, V. L. R.; Spalenka, J. W.; Schülli, T. U.

2013-11-01

X-ray nanobeams present the opportunity to obtain structural insight in materials with small volumes or nanoscale heterogeneity. The effective spatial resolution of the information derived from nanobeam techniques depends on the stability and precision with which the relative position of the x-ray optics and sample can be controlled. Nanobeam techniques include diffraction, imaging, and coherent scattering, with applications throughout materials science and condensed matter physics. Sample positioning is a significant mechanical challenge for x-ray instrumentation providing vacuum or controlled gas environments at elevated temperatures. Such environments often have masses that are too large for nanopositioners capable of the required positional accuracy of the order of a small fraction of the x-ray spot size. Similarly, the need to place x-ray optics as close as 1 cm to the sample places a constraint on the overall size of the sample environment. We illustrate a solution to the mechanical challenge in which compact ion-pumped ultrahigh vacuum chambers with masses of 1-2 kg are integrated with nanopositioners. The overall size of the environment is sufficiently small to allow their use with zone-plate focusing optics. We describe the design of sample environments for elevated-temperature nanobeam diffraction experiments demonstrate in situ diffraction, reflectivity, and scanning nanobeam imaging of the ripening of Au crystallites on Si substrates.

Formation of Porous Germanium Layers by Silver-Ion Implantation

NASA Astrophysics Data System (ADS)

Stepanov, A. L.; Vorob'ev, V. V.; Nuzhdin, V. I.; Valeev, V. F.; Osin, Yu. N.

2018-04-01

We propose a method for the formation of porous germanium ( P-Ge) layers containing silver nanoparticles by means of high-dose implantation of low-energy Ag+ ions into single-crystalline germanium ( c-Ge). This is demonstrated by implantation of 30-keV Ag+ ions into a polished c-Ge plate to a dose of 1.5 × 1017 ion/cm2 at an ion beam-current density of 5 μA/cm2. Examination by high-resolution scanning electron microscopy (SEM), atomic-force microscopy (AFM), X-ray diffraction (XRD), energy-dispersive X-ray (EDX) microanalysis, and reflection high-energy electron diffraction (RHEED) showed that the implantation of silver ions into c-Ge surface led to the formation of a P-Ge layer with spongy structure comprising a network of interwoven nanofibers with an average diameter of ˜10-20 nm Ag nanoparticles on the ends of fibers. It is also established that the formation of pores during Ag+ ion implantation is accompanied by effective sputtering of the Ge surface.

Investigation of high-energy ion-irradiated MA957 using synchrotron radiation under in-situ tension

DOE PAGES

Mo, Kun; Yun, Di; Miao, Yinbin; ...

2016-01-02

In this paper, an MA957 oxide dispersion-strengthened (ODS) alloy was irradiated with high-energy ions in the Argonne Tandem Linac Accelerator System. Fe ions at an energy of 84 MeV bombarded MA957 tensile specimens, creating a damage region similar to 7.5 μm in depth; the peak damage (similar to 40 dpa) was estimated to be at similar to 7 μm from the surface. Following the irradiation, in-situ high-energy X-ray diffraction measurements were performed at the Advanced Photon Source in order to study the dynamic deformation behavior of the specimens after ion irradiation damage. In-situ X-ray measurements taken during tensile testing ofmore » the ion-irradiated MA957 revealed a difference in loading behavior between the irradiated and un-irradiated regions of the specimen. At equivalent applied stresses, lower lattice strains were found in the radiation-damaged region than those in the un-irradiated region. This might be associated with a higher level of Type II stresses as a result of radiation hardening. The study has demonstrated the feasibility of combining high-energy ion radiation and high-energy synchrotron X-ray diffraction to study materials' radiation damage in a dynamic manner.« less

Synchrotron-radiation X-ray diffraction evidence of the emergence of ferroelectricity in LiTaO3 by ordering of a disordered Li ion in the polar direction

NASA Astrophysics Data System (ADS)

Zhang, Zhi-Gang; Abe, Tomohiro; Moriyoshi, Chikako; Tanaka, Hiroshi; Kuroiwa, Yoshihiro

2018-07-01

Synchrotron-radiation X-ray diffraction studies as a function of temperature reveal the structural origin of the spontaneous polarization and related lattice strains in stoichiometric LiTaO3. Electron charge density distribution maps visualized by the maximum entropy method clearly demonstrate that ordering of the disordered Li ion in the polar direction accompanied by deformation of the oxygen octahedra lead to the ferroelectric phase transition. The ionic polarization attributed to the ionic displacements is dominant in the polar structure. The structural change occurs continuously at the phase transition temperature, which suggests a second-order phase transition.

An electrochemical cell with sapphire windows for operando synchrotron X-ray powder diffraction and spectroscopy studies of high-power and high-voltage electrodes for metal-ion batteries.

PubMed

Drozhzhin, Oleg A; Tereshchenko, Ivan V; Emerich, Hermann; Antipov, Evgeny V; Abakumov, Artem M; Chernyshov, Dmitry

2018-03-01

A new multi-purpose operando electrochemical cell was designed, constructed and tested on the Swiss-Norwegian Beamlines BM01 and BM31 at the European Synchrotron Radiation Facility. Single-crystal sapphire X-ray windows provide a good signal-to-noise ratio, excellent electrochemical contact because of the constant pressure between the electrodes, and perfect electrochemical stability at high potentials due to the inert and non-conductive nature of sapphire. Examination of the phase transformations in the Li 1-x Fe 0.5 Mn 0.5 PO 4 positive electrode (cathode) material at C/2 and 10C charge and discharge rates, and a study of the valence state of the Ni cations in the Li 1-x Ni 0.5 Mn 1.5 O 4 cathode material for Li-ion batteries, revealed the applicability of this novel cell design to diffraction and spectroscopic investigations of high-power/high-voltage electrodes for metal-ion batteries.

Rare earth-doped lead borate glasses and transparent glass-ceramics: structure-property relationship.

PubMed

Pisarski, W A; Pisarska, J; Mączka, M; Lisiecki, R; Grobelny, Ł; Goryczka, T; Dominiak-Dzik, G; Ryba-Romanowski, W

2011-08-15

Correlation between structure and optical properties of rare earth ions in lead borate glasses and glass-ceramics was evidenced by X-ray-diffraction, Raman, FT-IR and luminescence spectroscopy. The rare earths were limited to Eu(3+) and Er(3+) ions. The observed BO(3)↔BO(4) conversion strongly depends on the relative PbO/B(2)O(3) ratios in glass composition, giving important contribution to the luminescence intensities associated to (5)D(0)-(7)F(2) and (5)D(0)-(7)F(1) transitions of Eu(3+). The near-infrared luminescence and up-conversion spectra for Er(3+) ions in lead borate glasses before and after heat treatment were measured. The more intense and narrowing luminescence lines suggest partial incorporation of Er(3+) ions into the orthorhombic PbF(2) crystalline phase, which was identified using X-ray diffraction analysis. Copyright © 2010 Elsevier B.V. All rights reserved.

X-ray diffraction patterns and diffracted intensity of Kα spectral lines of He-like ions

NASA Astrophysics Data System (ADS)

Goyal, Arun; Khatri, Indu; Singh, A. K.; Sharma, Rinku; Mohan, Man

2017-09-01

In the present paper, we have calculated fine-structure energy levels related to the configurations 1s2s, 1s2p, 1s3s and 1s3p by employing GRASP2K code. We have also computed radiative data for transitions from 1s2p 1 P1o, 1s2p 3 P2o, 1s2p 3 P1o and 1s2s 3S1 to the ground state 1s2. We have made comparisons of our presented energy levels and transition wavelengths with available results compiled by NIST and good agreement is achieved. We have also provided X-ray diffraction (XRD) patterns of Kα spectral lines, namely w, x, y and z of Cu XXVIII, Kr XXXV and Mo with diffraction angle and maximum diffracted intensity which is not published elsewhere in the literature. We believe that our presented results may be beneficial in determination of the order parameter, X-ray crystallography, solid-state drug analysis, forensic science, geological and medical applications.

Probing the Li Insertion Mechanism of ZnFe 2O 4 in Li-Ion Batteries: A Combined X-Ray Diffraction, Extended X-Ray Absorption Fine Structure, and Density Functional Theory Study [Probing the Li insertion mechanism of ZnFe 2O 4 in Li ion batteries: A combined XRD, EXAFS, and DFT study

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

Zhang, Yiman; Pelliccione, Christopher J.; Brady, Alexander B.

Here, we report an extensive study on fundamental properties that determine the functional electrochemistry of ZnFe 2O 4 spinel (theoretical capacity of 1000 mAh/g). For the first time, the reduction mechanism is followed through a combination of in situ X-ray diffraction data, synchrotron based powder diffraction, and ex-situ extended X-ray absorption fine structure allowing complete visualization of reduction products irrespective of their crystallinity. The first 0.5 electron equivalents (ee) do not significantly change the starting crystal structure. Subsequent lithiation results in migration of Zn 2+ ions from 8a tetrahedral sites into vacant 16c sites. Density functional theory shows that Limore » + ions insert into 16c site initially and then 8a site with further lithiation. Fe metal is formed over the next eight ee of reduction with no evidence of concurrent Zn 2+ reduction to Zn metal. Despite the expected formation of LiZn alloy from the electron count, we find no evidence for this phase under the tested conditions. Additionally, upon oxidation to 3 V, we observe an FeO phase with no evidence of Fe 2O 3. Electrochemistry data show higher electron equivalent transfer than can be accounted for solely based on ZnFe 2O 4 reduction indicating excess capacity ascribed to carbon reduction or surface electrolyte interphase formation.« less

Probing the Li Insertion Mechanism of ZnFe 2O 4 in Li-Ion Batteries: A Combined X-Ray Diffraction, Extended X-Ray Absorption Fine Structure, and Density Functional Theory Study [Probing the Li insertion mechanism of ZnFe 2O 4 in Li ion batteries: A combined XRD, EXAFS, and DFT study

DOE PAGES

Zhang, Yiman; Pelliccione, Christopher J.; Brady, Alexander B.; ...

2017-04-24

Here, we report an extensive study on fundamental properties that determine the functional electrochemistry of ZnFe 2O 4 spinel (theoretical capacity of 1000 mAh/g). For the first time, the reduction mechanism is followed through a combination of in situ X-ray diffraction data, synchrotron based powder diffraction, and ex-situ extended X-ray absorption fine structure allowing complete visualization of reduction products irrespective of their crystallinity. The first 0.5 electron equivalents (ee) do not significantly change the starting crystal structure. Subsequent lithiation results in migration of Zn 2+ ions from 8a tetrahedral sites into vacant 16c sites. Density functional theory shows that Limore » + ions insert into 16c site initially and then 8a site with further lithiation. Fe metal is formed over the next eight ee of reduction with no evidence of concurrent Zn 2+ reduction to Zn metal. Despite the expected formation of LiZn alloy from the electron count, we find no evidence for this phase under the tested conditions. Additionally, upon oxidation to 3 V, we observe an FeO phase with no evidence of Fe 2O 3. Electrochemistry data show higher electron equivalent transfer than can be accounted for solely based on ZnFe 2O 4 reduction indicating excess capacity ascribed to carbon reduction or surface electrolyte interphase formation.« less

Evolution of the magnetic and structural properties of Fe 1 - x Co x V 2 O 4

DOE PAGES

Sinclair, R.; Ma, Jie; Cao, H. B.; ...

2015-10-12

The magnetic and structural properties of single-crystal Fe 1-xCo xV 2O 4 samples have been investigated by performing specific heat, susceptibility, neutron diffraction, and x-ray diffraction measurements. As the orbital-active Fe 2+ ions with larger ionic size are gradually substituted by the orbital-inactive Co 2+ ions with smaller ionic size, the system approaches the itinerant electron limit with decreasing V-V distance. Then, various factors such as the Jahn-Teller distortion and the spin-orbital coupling of the Fe 2+ ions on the A sites and the orbital ordering and electronic itinerancy of the V 3+ ions on the B sites compete withmore » each other to produce a complex magnetic and structural phase diagram. Finally, this phase diagram is compared to those of Fe 1-xMn xV 2O 4 and Mn 1-xCo xV 2O 4 to emphasize several distinct features.« less

Understanding the initial irreversibility of metal sulfides for sodium-ion batteries via operando techniques

DOE PAGES

Wang, Liguang; Wang, Jiajun; Guo, Fangmin; ...

2018-11-13

Transition metal sulfides are promising high capacity anodes for sodium-ion batteries in terms of the conversion reaction with multiple alkali metal ions. Nonetheless, some inherent challenges such as sluggish sodium ion diffusion kinetics, large volume change, and poor cycle stability limit their implementation. Addressing these issues necessitates a comprehensive understanding the complex sodium ion storage mechanism particularly at the initial cycle. Here, taking nickel subsulfide as a model material, we reveal the complicated conversion reaction mechanism upon the first cycle by combining in operando 2D transmission X-ray microscopy with X-ray absorption spectroscopy, ex-situ 3D nano-tomography, high-energy X-ray diffraction and electrochemicalmore » impedance spectroscopy. This study demonstrates that the microstructure evolution, inherent slow sodium ions diffusion kinetics, and slow ion mobility at the two-phase interface contribute to the high irreversible capacity upon the first cycle. Finally, such understandings are critical for developing the conversion reaction materials with the desired electrochemical activity and stability.« less

Understanding the initial irreversibility of metal sulfides for sodium-ion batteries via operando techniques

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

Wang, Liguang; Wang, Jiajun; Guo, Fangmin

Transition metal sulfides are promising high capacity anodes for sodium-ion batteries in terms of the conversion reaction with multiple alkali metal ions. Nonetheless, some inherent challenges such as sluggish sodium ion diffusion kinetics, large volume change, and poor cycle stability limit their implementation. Addressing these issues necessitates a comprehensive understanding the complex sodium ion storage mechanism particularly at the initial cycle. Here, taking nickel subsulfide as a model material, we reveal the complicated conversion reaction mechanism upon the first cycle by combining in operando 2D transmission X-ray microscopy with X-ray absorption spectroscopy, ex-situ 3D nano-tomography, high-energy X-ray diffraction and electrochemicalmore » impedance spectroscopy. This study demonstrates that the microstructure evolution, inherent slow sodium ions diffusion kinetics, and slow ion mobility at the two-phase interface contribute to the high irreversible capacity upon the first cycle. Finally, such understandings are critical for developing the conversion reaction materials with the desired electrochemical activity and stability.« less

Magnetic and topographical modifications of amorphous Co-Fe thin films induced by high energy Ag7+ ion irradiation

NASA Astrophysics Data System (ADS)

Pookat, G.; Hysen, T.; Al-Harthi, S. H.; Al-Omari, I. A.; Lisha, R.; Avasthi, D. K.; Anantharaman, M. R.

2013-09-01

We have investigated the effects of swift heavy ion irradiation on thermally evaporated 44 nm thick, amorphous Co77Fe23 thin films on silicon substrates using 100 MeV Ag7+ ions fluences of 1 × 1011 ions/cm2, 1 × 1012 ions/cm2, 1 × 1013 ions/cm2, and 3 × 1013 ions/cm2. The structural modifications upon swift heavy irradiation were investigated using glancing angle X-ray diffraction. The surface morphological evolution of thin film with irradiation was studied using Atomic Force Microscopy. Power spectral density analysis was used to correlate the roughness variation with structural modifications investigated using X-ray diffraction. Magnetic measurements were carried out using vibrating sample magnetometry and the observed variation in coercivity of the irradiated films is explained on the basis of stress relaxation. Magnetic force microscopy images are subjected to analysis using the scanning probe image processor software. These results are in agreement with the results obtained using vibrating sample magnetometry. The magnetic and structural properties are correlated.

Investigations on structural and photoluminescence mechanism of cerium doped L-Histidine hydrochloride mono hydrate single crystals for optical applications

NASA Astrophysics Data System (ADS)

Rajyalakshmi, S.; Ramachandra Rao, K.; Brahmaji, B.; Samatha, K.; Visweswara Rao, T. K.; Ramakrishna, Y.

2017-02-01

Semi organic nonlinear optical material of Ce3+ ion added L-Histidine hydrochloride monohydrate (LHHC) crystals have been grown successfully by the slow evaporation solution technique (SEST) as well as Sankaranarayanan-Ramasamy (SR) technique. Unit cell data have been measured from the single crystal X-ray diffraction analysis and High resolution X-ray diffraction analysis (HRXRD) study shows relatively a good crystalline perfection. Fourier transform infra-red spectroscopy (FTIR) spectra indicates that the Ce3+ ion is coordinated with carboxylate group of grown crystal. The lower UV-cutoff wavelength of the incorporation of Ce3+ ion in LHHC is 240 nm. The incorporation of Ce3+ ion in the crystal lattice was observed by energy dispersive X-ray analysis (EDAX). The nonlinear optical (NLO) efficiency of SR-grown crystal is 3.7 times greater with respect to potassium dihydrogen phosphate (KDP). We report first-time the photoluminescence (PL) mechanism of emission spectrum, which shows broad band located at 350 nm corresponding to 5d → 4f transition of Ce3+ ion and excited by 250 nm wavelength. The excitation spectrum shows a band at 258 nm due to the 4f → 5d transition of Ce3+ ion. The nature of decay curve of the grown crystal is bi-exponential with a long life time of τ2 is 8.8270 μs.

Lattice modification in KTiOPO4 by hydrogen and helium sequentially implantation in submicrometer depth

NASA Astrophysics Data System (ADS)

Ma, Changdong; Lu, Fei; Xu, Bo; Fan, Ranran

2016-05-01

We investigated lattice modification and its physical mechanism in H and He co-implanted, z-cut potassium titanyl phosphate (KTiOPO4). The samples were implanted with 110 keV H and 190 keV He, both to a fluence of 4 × 1016 cm-2, at room temperature. Rutherford backscattering/channeling, high-resolution x-ray diffraction, and transmission electron microscopy were used to examine the implantation-induced structural changes and strain. Experimental and simulated x-ray diffraction results show that the strain in the implanted KTiOPO4 crystal is caused by interstitial atoms. The strain and stress are anisotropic and depend on the crystal's orientation. Transmission electron microscopy studies indicate that ion implantation produces many dislocations in the as-implanted samples. Annealing can induce ion aggregation to form nanobubbles, but plastic deformation and ion out-diffusion prevent the KTiOPO4 surface from blistering.

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

Ma, Changdong; Department of Radiation Oncology, Qilu Hospital, Shandong University, Jinan, Shandong 250012; Lu, Fei, E-mail: lufei@sdu.edu.cn

We investigated lattice modification and its physical mechanism in H and He co-implanted, z-cut potassium titanyl phosphate (KTiOPO{sub 4}). The samples were implanted with 110 keV H and 190 keV He, both to a fluence of 4 × 10{sup 16 }cm{sup −2}, at room temperature. Rutherford backscattering/channeling, high-resolution x-ray diffraction, and transmission electron microscopy were used to examine the implantation-induced structural changes and strain. Experimental and simulated x-ray diffraction results show that the strain in the implanted KTiOPO{sub 4} crystal is caused by interstitial atoms. The strain and stress are anisotropic and depend on the crystal's orientation. Transmission electron microscopy studies indicate that ion implantationmore » produces many dislocations in the as-implanted samples. Annealing can induce ion aggregation to form nanobubbles, but plastic deformation and ion out-diffusion prevent the KTiOPO{sub 4} surface from blistering.« less

Understanding self ion damage in FCC Ni-Cr-Fe based alloy using X-ray diffraction techniques

NASA Astrophysics Data System (ADS)

Halder Banerjee, R.; Sengupta, P.; Chatterjee, A.; Mishra, S. C.; Bhukta, A.; Satyam, P. V.; Samajdar, I.; Dey, G. K.

2018-04-01

Using X-ray diffraction line profile analysis (XRDLPA) approach the radiation response of FCC Ni-Cr-Fe based alloy 690 to 1.5 and 3 MeV Ni2+ ion damage was quantified in terms of its microstructural parameters. These microstructural parameters viz. average domain size, microstrain and dislocation density were found to vary anisotropically with fluence. The anisotropic behaviour is mainly attributable to presence of twins in pre-irradiated microstructure. After irradiation, surface roughness increases as a function of fluence attributable to change in surface and sub-surface morphology caused by displacement cascade, defects and sputtered atoms created by incident energetic ion. The radiation hardening in case of 1.5 MeV Ni2+ irradiated specimens too is a consequence of the increase in dislocation density formed by interaction of radiation induced defects with pre-existing dislocations. At highest fluence there is an initiation of saturation.

Preliminary experiments on the reduction of the uranyl ion to uraninite by carbonaceous substances

USGS Publications Warehouse

Breger, Irving A.; Moore, Richard T.

1955-01-01

An aqueous solution of uranyl sulfate containing a suspension of subbituminous coal has been heated at 210 C for three days. Examination of the coal at the end of the experiment showed it to contain 31.8 percent uranium recognizable as uraninite by a sharp, strong X-ray diffraction pattern. A similar experiment with degraded spruce wood also led to the formation of uraninite but in lesser quantity and with broader lines in the X-ray diffraction pattern. The ability of coal or wood to reduce the uranyl ion is a critical factor in the correlation of studies of uraniferous coals containing the uranyl ion with studies of uraninite-bearing coalified wood from the Colorado Plateau. Although these results are based an preliminary experiments, they are extremely important geochemically and warrant the development of the series of controlled studies that are proposed.

Synthesis of nanocrystalline CdS thin film by SILAR and their characterization

NASA Astrophysics Data System (ADS)

Mukherjee, A.; Satpati, B.; Bhattacharyya, S. R.; Ghosh, R.; Mitra, P.

2015-01-01

Cadmium sulphide (CdS) thin film was prepared by successive ion layer adsorption and reaction (SILAR) technique using ammonium sulphide as anionic precursor. Characterization techniques of XRD, SEM, TEM, FTIR and EDX were utilized to study the microstructure of the films. Structural characterization by x-ray diffraction reveals the polycrystalline nature of the films. Cubic structure is revealed from X-ray diffraction and selected area diffraction (SAD) patterns. The particle size estimated using X-ray line broadening method is approximately 7 nm. Instrumental broadening was taken into account while particle size estimation. TEM shows CdS nanoparticles in the range 5-15 nm. Elemental mapping using EFTEM reveals good stoichiometric composition of CdS. Characteristic stretching vibration mode of CdS was observed in the absorption band of FTIR spectrum. Optical absorption study exhibits a distinct blue shift in band gap energy value of about 2.56 eV which confirms the size quantization.

Structure and magnetic properties of Fe-doped ZnO prepared by the sol-gel method.

PubMed

Liu, Huilian; Yang, Jinghai; Zhang, Yongjun; Yang, Lili; Wei, Maobin; Ding, Xue

2009-04-08

Zn(0.97)Fe(0.03)O nanoparticles were synthesized by the sol-gel method. X-ray diffraction (XRD) and transmission electron microscope (TEM) analysis revealed that the samples had pure ZnO wurtzite structure and Fe ions were well incorporated into the ZnO crystal lattice. X-ray photoelectron spectroscopy (XPS) showed that both Fe(2+) and Fe(3+) existed in Zn(0.97)Fe(0.03)O. The result of x-ray absorption near-edge structure (XANES) further testified that Fe ions took the place of Zn sites in our samples. Magnetic measurements indicated that Zn(0.97)Fe(0.03)O was ferromagnetic at room temperature.

Catharanthus roseus: a natural source for the synthesis of silver nanoparticles

PubMed Central

Mukunthan, KS; Elumalai, EK; Patel, Trupti N; Murty, V Ramachandra

2011-01-01

Objective To develop a simple rapid procedure for bioreduction of silver nanoparticles (AgNPs) using aqueous leaves extracts of Catharanthus roseus (C. roseus). Methods Characterization were determined by using UV-Vis spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray and X-ray diffraction. Results SEM showed the formation of silver nanoparticles with an average size of 67 nm to 48 nm. X-ray diffraction analysis showed that the particles were crystalline in nature with face centered cubic geometry. Conclusions C. roseus demonstrates strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag+ to Ag0). This study provides evidence for developing large scale commercial production of value-added products for biomedical/nanotechnology-based industries. PMID:23569773

The Great Fallacy of the H Plus Ion and the True Nature of H30 Plus.

ERIC Educational Resources Information Center

Giguere, Paul A.

1979-01-01

Experimental and theoretical data are presented which verifies the existence of the hydronium ion. This existence was confirmed directly by x-ray and neutron diffraction in hydrochloric acid. Recommended is the abandonment of the erroneous hydrogen ion formulation and names such as proton hydrate. (BT)

Effects of vanadium ion implantation on microstructure, mechanical and tribological properties of TiN coatings

NASA Astrophysics Data System (ADS)

Deng, Bin; Tao, Ye; Guo, Deliang

2012-09-01

TiN coatings were deposited on the substrates of cemented carbide (WC-TiC-Co) by Magnetic Filter Arc Ion Plating (MFAIP) and then implanted with vanadium through Metal Vacuum Vapor Arc (MEVVA) ion source with the doses of 1 × 1017 and 5 × 1017 ions/cm2 at 40 kV. The microstructures and chemical compositions of the V-implanted TiN coatings were investigated using Glancing Incidence X-ray Diffraction (GIXRD) and X-ray Photoelectron Spectroscopy (XPS), together with the mechanical and tribological properties of coatings were characterized using nano-indentation and ball-on-disk tribometer. It was found that the diffraction peaks of the V-implanted TiN coatings at the doses of 5 × 1017 ions/cm2 shifted to higher angles and became broader. The hardness and elastic modulus of TiN coatings increased after V ion implantation. The wear mechanism for both un-implanted and V-implanted TiN coatings against GCr15 steel ball was adhesive wear, and the V-implanted TiN coatings had a lower friction coefficient as well as a better wear resistance

X ray reflection masks: Manufacturing, characterization and first tests

NASA Astrophysics Data System (ADS)

Rahn, Stephen

1992-09-01

SXPL (Soft X-ray Projection Lithography) multilayer mirrors are characterized, laterally structured and then used as reflection masks in a projecting lithography procedure. Mo/Si-multilayer mirrors with a 2d in the region of 14 nm were characterized by Cu-k(alpha) grazing incidence as well as soft X-ray normal incidence reflectivity measurements. The multilayer mirrors were patterned by reactive ion etching with CF4 using a photoresist as etch mask, thus producing X-ray reflection masks. The masks were tested at the synchrotron radiation laboratory of the electron accelerator ELSA. A double crystal X-ray monochromator was modified so as to allow about 0.5 sq cm of the reflection mask to be illuminated by white synchrotron radiation. The reflected patterns were projected (with an energy of 100 eV) onto a resist and structure sizes down to 8 micrometers were nicely reproduced. Smaller structures were distorted by Fresnel-diffraction. The theoretically calculated diffraction images agree very well with the observed images.

Combined operando X-ray diffraction–electrochemical impedance spectroscopy detecting solid solution reactions of LiFePO4 in batteries

PubMed Central

Hess, Michael; Sasaki, Tsuyoshi; Villevieille, Claire; Novák, Petr

2015-01-01

Lithium-ion batteries are widely used for portable applications today; however, often suffer from limited recharge rates. One reason for such limitation can be a reduced active surface area during phase separation. Here we report a technique combining high-resolution operando synchrotron X-ray diffraction coupled with electrochemical impedance spectroscopy to directly track non-equilibrium intermediate phases in lithium-ion battery materials. LiFePO4, for example, is known to undergo phase separation when cycled under low-current-density conditions. However, operando X-ray diffraction under ultra-high-rate alternating current and direct current excitation reveal a continuous but current-dependent, solid solution reaction between LiFePO4 and FePO4 which is consistent with previous experiments and calculations. In addition, the formation of a preferred phase with a composition similar to the eutectoid composition, Li0.625FePO4, is evident. Even at a low rate of 0.1C, ∼20% of the X-ray diffractogram can be attributed to non-equilibrium phases, which changes our understanding of the intercalation dynamics in LiFePO4. PMID:26345306

Latex-mediated synthesis of ZnS nanoparticles: green synthesis approach

NASA Astrophysics Data System (ADS)

Hudlikar, Manish; Joglekar, Shreeram; Dhaygude, Mayur; Kodam, Kisan

2012-05-01

A low-cost, green synthesis of ZnS nanoparticles is reported using 0.3 % latex solution prepared from Jatropha curcas L. ZnS nanoparticles were characterized by X-ray diffraction, selected area electron diffraction, transmission electron microscopy, energy dispersive analysis of X-rays, UV-vis optical absorption and photoluminescence techniques. Fourier Transform Infrared Spectroscopy was performed to find the role of cyclic peptides namely curcacycline A (an octapeptide), curcacycline B (a nonapeptide) and curcain (an enzyme) as a possible reducing and stabilizing agents present in the latex of J. curcas L. The average size of ZnS nanoparticles was found to be 10 nm. Latex of J. curcas L. itself acts as a source of sulphide (S-2) ions that are donated to Zn ions under present experimental conditions. Source of sulphide (S-2) ions is still unclear, but we speculate that cysteine or thiol residues present in enzyme curcain may be donating these sulphide (S-2) ions.

Polaron hopping in olivine phosphates studied by nuclear resonant scattering

NASA Astrophysics Data System (ADS)

Tracy, Sally June

Valence fluctuations of Fe2+ and Fe3+ were studied in a solid solution of LixFePO4 by nuclear resonant forward scattering of synchrotron x rays while the sample was heated in a diamond-anvil pressure cell. The spectra acquired at different temperatures and pressures were analyzed for the frequencies of valence changes using the Blume-Tjon model of a system with a fluctuating Hamiltonian. These frequencies were analyzed to obtain activation energies and an activation volume for polaron hopping. There was a large suppression of hopping frequency with pressure, giving an anomalously large activation volume. This large, positive value is typical of ion diffusion, which indicates correlated motions of polarons, and Li+ ions that alter the dynamics of both. In a parallel study of NaxFePO4, the interplay between sodium ordering and electron mobility was investigated using a combination of synchrotron x-ray diffraction and nuclear resonant scattering. Conventional Mossbauer spectra were collected while the sample was heated in a resistive furnace. An analysis of the temperature evolution of the spectral shapes was used to identify the onset of fast electron hopping and determine the polaron hopping rate. Synchrotron x-ray diffraction measurements were carried out in the same temperature range. Reitveld analysis of the diffraction patterns was used to determine the temperature of sodium redistribution on the lattice. The diffraction analysis also provides new information about the phase stability of the system. The temperature evolution of the iron site occupancies from the Mossbauer measurements, combined with the synchrotron diffraction results give strong evidence for a relationship between the onset of fast electron dynamics and the redistribution of sodium in the lattice. Measurements of activation barriers for polaron hopping gave fundamental insights about the correlation between electronic carriers and mobile ions. This work established that polaron-ion interactions can alter the local dynamics of electron and ion transport. These types of coupled processes may be common in many materials used for battery electrodes, and new details concerning the influence of polaron-ion interactions on the charge dynamics are relevant to optimizing their electrochemical performance.

Synthesis and Characterization of Nd(3+)-Doped CaF2 Nanoparticles.

PubMed

Yuan, Dan; Li, Weiwei; Mei, Bingchu; Song, Jinghong

2015-12-01

The Ca(1-x)F(2+x):Nd(x) nanoparticles were synthesized by chemical direct precipitation method. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Image analyzer, absorption spectrum and transmittance were taken to characterization the phases, morphologies, sizes, size distribution and optical properties of the samples. The results indicate that the Ca(1-x)F(2+x):Nd(x) samples can be rationally modified in size and morphology by altering the Nd3+ ions doping concentration. With increasing concentration of Nd3+ ions, the particle size decreased from 24 to 14 nm, the intensity of the diffraction peaks decreased, the Ca(1-x)F(2+x):Nd(x) particles aggregated ion of the formed clusters which should have an effect on both speed and orientation of the particles growth. The transmittance of ceramics with a thickness of 2 mm showed that the transmittance can reach 90% when the doping concentration was 5%, which should be profitable for LD pumping.

A radially accessible tubular in situ X-ray cell for spatially resolved operando scattering and spectroscopic studies of electrochemical energy storage devices

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

Liu, Hao; Allan, Phoebe K.; Borkiewicz, Olaf J.

2016-09-16

A tubularoperandoelectrochemical cell has been developed to allow spatially resolved X-ray scattering and spectroscopic measurements of individual cell components, or regions thereof, during device operation. These measurements are enabled by the tubular cell geometry, wherein the X-ray-transparent tube walls allow radial access for the incident and scattered/transmitted X-ray beam; by probing different depths within the electrode stack, the transformation of different components or regions can be resolved. The cell is compatible with a variety of synchrotron-based scattering, absorption and imaging methodologies. The reliability of the electrochemical cell and the quality of the resulting X-ray scattering and spectroscopic data are demonstratedmore » for two types of energy storage: the evolution of the distribution of the state of charge of an Li-ion battery electrode during cycling is documented using X-ray powder diffraction, and the redistribution of ions between two porous carbon electrodes in an electrochemical double-layer capacitor is documented using X-ray absorption near-edge spectroscopy.« less

Interplay between atomic disorder, lattice swelling and defect energy in ion-irradiation-induced amorphization of SiC

DOE PAGES

Debelle, Aurelien; Boulle, Alexandre; Chartier, Alain; ...

2014-11-25

We present a combination of experimental and computational evaluations of disorder level and lattice swelling in ion-irradiated materials. Information obtained from X-ray diffraction experiments is compared to X-ray diffraction data generated using atomic-scale simulations. The proposed methodology, which can be applied to a wide range of crystalline materials, is used to study the amorphization process in irradiated SiC. Results show that this process can be divided into two steps. In the first step, point defects and small defect clusters are produced and generate both large lattice swelling and high elastic energy. In the second step, enhanced coalescence of defects andmore » defect clusters occurs to limit this increase in energy, which rapidly leads to complete amorphization.« less

Nanoscale interfacial mixing of Au/Bi layers using MeV ion beams

NASA Astrophysics Data System (ADS)

Prusty, Sudakshina; Siva, V.; Ojha, S.; Kabiraj, D.; Sahoo, P. K.

2017-05-01

We have studied nanoscale mixing of thermally deposited double bilayer films of Au/Bi after irradiating them by 1.5 MeV Au2+ ions. Post irradiation effects on the morphology and elemental identification in these films are studied by Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS). Glancing angle X-ray diffraction (GAXRD) of the samples indicate marginal changes in the irradiated samples due to combined effect of nuclear and electronic energy loss. The interfacial mixing is studied by Rutherford backscattering (RBS).

Synthesis and Properties of Ortho-Nitro-Fe Complex

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

Mishra, A.; Mishra, Niyati; Sharma, R.

2011-07-15

Ortho-Nitro-Fe complex (Transition metal complex) has synthesized by chemical route method and properties of made complex has characterized by X-Ray diffraction (XRD), Moessbauer spectroscopy, Fourier transformation infra-red spectroscopy (FTIR) and X-Ray photoelectron spectroscopy (XPS). XRD analysis shows that sample is crystalline in nature and having particle size in the range of few nano meters. Moessbauer spectroscopy at room temperature shows the oxidation state of Iron (central metal ion) after complaxasion. FTIR spectra of the complex confirms the coordination of metal ion with ligand.

Solid state synthesis of layered sodium manganese oxide for sodium-ion battery by in-situ high energy X-ray diffraction and X-ray absorption near edge spectroscopy [Solid state synthesis of layered sodium manganese oxide for sodium-ion battery by in-situ HEXRD and XANES

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

Ma, Tianyuan; Xu, Gui -Liang; Zeng, Xiaoqiao

In situ high energy X-ray diffraction (HEXRD) and in situ X-ray absorption near edge spectroscopy (XANES) were carried out to understand the soild state synthesis of Na xMnO 2, with particular interest on the synthesis of P2 type Na 2/3MnO 2. It was found that there were multi intermediate phases formed before NaMnO 2 appeared at about 600 °C. And the final product after cooling process is a combination of O'3 NaMnO 2 with P2 Na 2/3MnO 2. A P2 type Na 2/3MnO 2 was synthesized at reduced temperature (600 °C). The influence of Na 2CO 3 impurity on themore » electrochemical performance of P2 Na 2/3MnO 2 was thoroughly investigated in our work. It was found that the content of Na 2CO 3 can be reduced by optimizing Na 2CO 3/MnCO 3 ratio during the solid state reaction or other post treatment such as washing with water. Lastly, we expected our results could provide a good guide for future development of high performance cathode materials for sodium-ion batteries.« less

Solid state synthesis of layered sodium manganese oxide for sodium-ion battery by in-situ high energy X-ray diffraction and X-ray absorption near edge spectroscopy [Solid state synthesis of layered sodium manganese oxide for sodium-ion battery by in-situ HEXRD and XANES

DOE PAGES

Ma, Tianyuan; Xu, Gui -Liang; Zeng, Xiaoqiao; ...

2016-12-07

In situ high energy X-ray diffraction (HEXRD) and in situ X-ray absorption near edge spectroscopy (XANES) were carried out to understand the soild state synthesis of Na xMnO 2, with particular interest on the synthesis of P2 type Na 2/3MnO 2. It was found that there were multi intermediate phases formed before NaMnO 2 appeared at about 600 °C. And the final product after cooling process is a combination of O'3 NaMnO 2 with P2 Na 2/3MnO 2. A P2 type Na 2/3MnO 2 was synthesized at reduced temperature (600 °C). The influence of Na 2CO 3 impurity on themore » electrochemical performance of P2 Na 2/3MnO 2 was thoroughly investigated in our work. It was found that the content of Na 2CO 3 can be reduced by optimizing Na 2CO 3/MnCO 3 ratio during the solid state reaction or other post treatment such as washing with water. Lastly, we expected our results could provide a good guide for future development of high performance cathode materials for sodium-ion batteries.« less

Temperature dependence of helium-implantation-induced lattice swelling in polycrystalline tungsten: X-ray micro-diffraction and Eigenstrain modelling

DOE PAGES

de Broglie, I.; Beck, C. E.; Liu, W.; ...

2015-05-30

Using synchrotron X-ray micro-diffraction and Eigenstrain analysis the distribution of lattice swelling near grain boundaries in helium-implanted polycrystalline tungsten is quantified. Samples heat-treated at up to 1473 K after implantation show less uniform lattice swelling that varies significantly from grain to grain compared to as-implanted samples. An increase in lattice swelling is found in the vicinity of some grain boundaries, even at depths beyond the implanted layer. As a result, these findings are discussed in terms of the evolution of helium-ion-implantation-induced defects.

Temperature dependence of helium-implantation-induced lattice swelling in polycrystalline tungsten: X-ray micro-diffraction and Eigenstrain modelling

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

de Broglie, I.; Beck, C. E.; Liu, W.

Using synchrotron X-ray micro-diffraction and Eigenstrain analysis the distribution of lattice swelling near grain boundaries in helium-implanted polycrystalline tungsten is quantified. Samples heat-treated at up to 1473 K after implantation show less uniform lattice swelling that varies significantly from grain to grain compared to as-implanted samples. An increase in lattice swelling is found in the vicinity of some grain boundaries, even at depths beyond the implanted layer. As a result, these findings are discussed in terms of the evolution of helium-ion-implantation-induced defects.

Investigations on the in vitro bioactivity of swift heavy oxygen ion irradiated hydroxyapatite.

PubMed

Suganthi, R V; Prakash Parthiban, S; Elayaraja, K; Girija, E K; Kulariya, P; Katharria, Y S; Singh, F; Asokan, K; Kanjilal, D; Narayana Kalkura, S

2009-12-01

The effect of swift heavy oxygen ion irradiation of hydroxyapatite on its in vitro bioactivity was studied. The irradiation experiment was performed using oxygen ions at energy of 100 MeV with 1 x 10(12) and 1 x 10(13) ions/cm2 fluence range. The irradiated samples were characterized by glancing angle X-ray diffraction (GXRD), photoluminescence spectroscopy (PL) and scanning electron microscopy (SEM). GXRD showed that irradiated samples exhibited better crystallinity. The irradiated samples revealed an increase in PL intensity. In addition, the irradiated hydroxyapatite was found to have enhanced bioactivity.

DetOx: a program for determining anomalous scattering factors of mixed-oxidation-state species.

PubMed

Sutton, Karim J; Barnett, Sarah A; Christensen, Kirsten E; Nowell, Harriott; Thompson, Amber L; Allan, David R; Cooper, Richard I

2013-01-01

Overlapping absorption edges will occur when an element is present in multiple oxidation states within a material. DetOx is a program for partitioning overlapping X-ray absorption spectra into contributions from individual atomic species and computing the dependence of the anomalous scattering factors on X-ray energy. It is demonstrated how these results can be used in combination with X-ray diffraction data to determine the oxidation state of ions at specific sites in a mixed-valance material, GaCl(2).

Fatigue of LiNi0.8Co0.15Al0.05O2 in commercial Li ion batteries

NASA Astrophysics Data System (ADS)

Kleiner, Karin; Dixon, Ditty; Jakes, Peter; Melke, Julia; Yavuz, Murat; Roth, Christina; Nikolowski, Kristian; Liebau, Verena; Ehrenberg, Helmut

2015-01-01

The degradation of LiNi0.8Co0.15Al0.05O2 (LNCAO), a cathode material in lithium-ion-batteries, was studied using in situ powder diffraction and in situ Ni K edge X-ray absorption spectroscopy (XAS). The fatigued material was taken from a 7 Ah battery which was cycled for 34 weeks under defined durability conditions. Meanwhile, a cell was stored, as reference, under controlled conditions without electrochemical treatment. The fatigued LNCAO used in this study showed a capacity loss of 26% ± 9% compared to the non-cycled material. During charge and discharge the local and the overall structure of LNCAO was investigated by X-ray near edge structure (XANES) analysis, the extended X-ray absorption fine structure (EXAFS) analysis and by using Rietveld refinement of in situ powder diffraction patterns. Both powder diffraction and XAS revealed additional, rhombohedral phases which do not change with electrochemical cycling. Moreover, a phase with the lattice parameters of fully lithiated LNCAO was still present in the fatigued material at high potentials, while it was absent in the non-fatigued reference material. The coexistence of these phases is described by domains within the LNCAO particles, in correlation with the observed fatigue.

Synthesis and Crystal Structure of Dibromido{2-[(4-tert-butylmethylphenyl) iminomethyl]pyridine-κ2 N, N'}Zinc

NASA Astrophysics Data System (ADS)

Khalaj, M.; Ghazanfarpour-Darjani, M.; Seftejani, F. B.; Lalegani, A.

2017-12-01

The title compound [Zn( dip)Br2] was synthesized using the Schiff base bidentate ligand (E)-4- tert-butyl- N-(pyridine-2-ylmethylene)benzeneamine ( dip) and zinc(II) bromide salts. It has been characterized by elemental analysis, X-ray diffraction, and optical spectroscopy. The X-ray diffraction analysis demonstrates that in this structure, the zinc(II) ion is located on an inversion center and exhibits a ZnN2Br2 tetrahedral geometry. In this structure the dip ligand is coordinated with zinc(II) ion in a cyclic-bidentate fashion forming a five-membered metallocyclic ring. The compound crystallizes in the monoclinic sp. gr. P21/ m with a = 9.2700(13) Å, b = 7.6128(11) Å, c = 12.3880(17) Å, and β = 97.021(3)°.

Valence, exchange interaction, and location of Mn ions in polycrystalline M nxG a1 -xN (x ≤0.04 )

NASA Astrophysics Data System (ADS)

Furrer, A.; Krämer, K. W.; Podlesnyak, A.; Pomjakushin, V.; Sheptyakov, D.; Safonova, O. V.

2018-04-01

We present an experimental study for polycrystalline samples of the diluted magnetic semiconductor M nxG a1 -xN (x ≤0.04 ) in order to address some of the existing controversial issues. X-ray and neutron diffraction, x-ray absorption near-edge structure, and electron paramagnetic resonance experiments were used to characterize the structural, electronic, and magnetic properties of the samples, and inelastic neutron scattering was employed to determine the magnetic excitations associated with Mn monomers and dimers. Our main conclusions are as follows: (i) The valence of the Mn ions is 2 + . (ii) The M n2 + ions experience a substantial single-ion axial anisotropy with parameter D =0.027 (3 )meV . (iii) Nearest-neighbor M n2 + ions are coupled antiferromagnetically. The exchange parameter J =-0.140 (7 )meV is independent of the Mn content x ; i.e., there is no evidence for hole-induced modifications of J towards a potentially high Curie temperature postulated in the literature.

Ion implantation for manufacturing bent and periodically bent crystals

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

Bellucci, Valerio; Camattari, Riccardo; Guidi, Vincenzo, E-mail: guidi@fe.infn.it

2015-08-10

Ion implantation is proposed to produce self-standing bent monocrystals. A Si sample 0.2 mm thick was bent to a radius of curvature of 10.5 m. The sample curvature was characterized by interferometric measurements; the crystalline quality of the bulk was tested by X-ray diffraction in transmission geometry through synchrotron light at ESRF (Grenoble, France). Dislocations induced by ion implantation affect only a very superficial layer of the sample, namely, the damaged region is confined in a layer 1 μm thick. Finally, an elective application of a deformed crystal through ion implantation is here proposed, i.e., the realization of a crystalline undulator to producemore » X-ray beams.« less

Low-energy ion beam-based deposition of gallium nitride

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

Vasquez, M. R., E-mail: mrvasquez@coe.upd.edu.ph; Wada, M.

2016-02-15

An ion source with a remote plasma chamber excited by a 13.56 MHz radio frequency power was used for low-energy broad ion beam extraction. Optical emission spectral analyses showed the sputtering and postionization of a liquid gallium (Ga) target placed in a chamber separated from the source bombarded by argon (Ar) plasma guided by a bent magnetic field. In addition, an E × B probe successfully showed the extraction of low-energy Ga and Ar ion beams using a dual-electrode extractor configuration. By introducing dilute amounts of nitrogen gas into the system, formation of thin Ga-based films on a silicon substratemore » was demonstrated as determined from X-ray diffraction and X-ray reflectivity studies.« less

Photometric study of single-shot energy-dispersive x-ray diffraction at a laser plasma facility

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

Hoidn, O. R.; Seidler, G. T., E-mail: seidler@uw.edu

The low repetition rates and possible shot-to-shot variations in laser-plasma studies place a high value on single-shot diagnostics. For example, white-beam scattering methods based on broadband backlighter x-ray sources are used to determine changes in the structure of laser-shocked crystalline materials by the evolution of coincidences of reciprocal lattice vectors and kinematically allowed momentum transfers. Here, we demonstrate that white-beam techniques can be extended to strongly disordered dense plasma and warm dense matter systems where reciprocal space is only weakly structured and spectroscopic detection is consequently needed to determine the static structure factor and thus, the ion-ion radial distribution function.more » Specifically, we report a photometric study of energy-dispersive x-ray diffraction (ED-XRD) for structural measurement of high energy density systems at large-scale laser facilities such as OMEGA and the National Ignition Facility. We find that structural information can be obtained in single-shot ED-XRD experiments using established backlighter and spectrometer technologies.« less

Syntheses, structures and properties of three new two-dimensional Cu(I)-Ln(III) heterometallic coordination polymers based on 2,2'-dipyridyl-5,5'-dicarboxylate ligands.

PubMed

Zhao, Junwei; Cheng, Yamin; Shang, Sensen; Zhang, Fang; Chen, Li; Chen, Lijuan

2013-12-01

Three new two-dimensional Cu(I)-Ln(III) heterometallic coordination polymers [Ln(III)Cu2(I)(Hbpdc)4] · Cl · xH2O [Ln(III) = La(III), x = 8 (1); Ln(III) = Pr(III), x=9 (2); Ln(III) = Eu(III), x = 8 (3)] (H2bpdc = 2,2'-bipyridyl-5,5'-dicarboxylic acid) have been prepared under hydrothermal conditions and structurally characterized by elemental analyses, inductively coupled plasma atomic emission spectrometry (ICP-AES) analyses, IR spectra, X-ray photoelectron spectroscopy (XPS) and single-crystal X-ray diffraction. X-ray diffraction indicates that the isomorphic 1-3 display the two-dimensional sheet structure constructed from [Cu(I)(Hbpdc)2](-) fragments through Ln(3+) connectors. Moreover, the solid-state photoluminescence measurements of 3 indicate that the Eu(III) ions, Hbpdc(-) ligands and Cu(I) cations make contributions to its luminescent properties simultaneously. Copyright © 2013 Elsevier B.V. All rights reserved.

Halide Ions Effects on Surface Excess of Long Chain Ionic Liquids Water Solutions

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

Wang, Wenjie; Sung, Woongmo; Ao, Mingqi

2013-10-07

The interfacial structure and composition of water solutions with alkylimidazolium ionic liquids varying in their halide anions ([C12mim][X], X = Cl and I) were investigated by X-ray near-total-reflection fluorescence spectroscopy and X-ray reflectivity measurements. We demonstrate that X-ray fluorescence and reflectivity techniques provide a more direct measurement of surface adsorption. Furthermore, we show that for [C12mim][Cl] and [C12mim][I] solutions with mixed inorganic salts (NaI, NaCl), I– ions replace Cl– above the critical micelle concentration (CMC) of [C12mim][Cl] at much lower concentrations of NaI, whereas NaCl concentrations a hundred times higher than the CMC of [C12mim][I] only partially replace the I–more » at the interface. Our surface-sensitive X-ray diffraction and spectroscopy provide two independent tools to directly determine the surface adsorption of ionic surfactants and the interfacial composition of the surface films.« less

Nanoscale femtosecond imaging of transient hot solid density plasmas with elemental and charge state sensitivity using resonant coherent diffraction

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

Kluge, T., E-mail: t.kluge@hzdr.de; Bussmann, M.; Huang, L. G., E-mail: lingen.huang@hzdr.de

Here, we propose to exploit the low energy bandwidth, small wavelength, and penetration power of ultrashort pulses from XFELs for resonant Small Angle Scattering (SAXS) on plasma structures in laser excited plasmas. Small angle scattering allows to detect nanoscale density fluctuations in forward scattering direction. Typically, the SAXS signal from laser excited plasmas is expected to be dominated by the free electron distribution. We propose that the ionic scattering signal becomes visible when the X-ray energy is in resonance with an electron transition between two bound states (resonant coherent X-ray diffraction). In this case, the scattering cross-section dramatically increases somore » that the signal of X-ray scattering from ions silhouettes against the free electron scattering background which allows to measure the opacity and derived quantities with high spatial and temporal resolution, being fundamentally limited only by the X-ray wavelength and timing. Deriving quantities such as ion spatial distribution, charge state distribution, and plasma temperature with such high spatial and temporal resolution will make a vast number of processes in shortpulse laser-solid interaction accessible for direct experimental observation, e.g., hole-boring and shock propagation, filamentation and instability dynamics, electron transport, heating, and ultrafast ionization dynamics.« less

Synthesis and characterization of rare-earth-doped calcium tungstate nanocrystals

NASA Astrophysics Data System (ADS)

Suneeta, P.; Rajesh, Ch.; Ramana, M. V.

2018-02-01

In this paper, we report synthesis and characterization of rare-earth-ion-doped calcium tungstate (CaWO4) nanocrystals (NCs). Rare-earth ions, such as gadolinium (Gd), neodymium (Nd), praseodymium (Pr), samarium (Sm) and holmium (Ho), were successfully doped in the CaWO4 NCs by changing the synthesis conditions. The adopted synthesis route was found to be fast and eco-friendly. Structural characterizations, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and compositional analysis, were performed using energy dispersive analysis of X-rays (EDAX) on as-synthesized NCs. The results indicate the size of the NCs ranging between 47 to 68nm and incorporation of rare-earth ions in CaWO4 NCs.

Plasma-assisted reduction of silver ions impregnated into a natural zeolite framework

NASA Astrophysics Data System (ADS)

Osonio, Airah P.; Vasquez, Magdaleno R.

2018-02-01

A green, dry, and energy-efficient method for the fabrication of silver-zeolite (AgZ) composite via 13.56 MHz radio-frequency plasma reduction is demonstrated. Impregnation by soaking and ion-exchange deposition were performed to load the silver ions (Ag+) into the sodium-zeolite samples. Characterization was performed by optical emission spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analyses. Results indicate the successful reduction of Ag+ to its metallic state on the surface of the zeolite with a mean diameter of 165 nm. This plasma-induced reduction technique opens possibilities in several areas including catalysis, adsorption, water treatment, and medicine.

FTIR spectroscopic, thermal and XRD characterization of hydroxyapatite from new natural sources

NASA Astrophysics Data System (ADS)

Shaltout, Abdallah A.; Allam, Moussa A.; Moharram, Mohamed A.

2011-12-01

The inorganic constituents of 5 different plants (leaves and stalks) were investigated by using Fourier transformer infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal analysis including thermal gravimetric analysis (TGA), derivative thermogravimetry (DTG) and differential scanning calorimetry (DSC). These plants are Catha edulis (Khat), basil, mint, green tea and trifolium. The absorption bands of carbonate ions CO 32- was exhibited at 1446 cm -1, and the phosphate ions PO 43- was assigned at 1105 and 1035 cm -1. At high temperatures (600, 700 and 600 °C) further absorption bands of the phosphate ions PO 43- was assigned at the frequencies 572, 617, 962, 1043 and 1110 cm -1 and the vibrational absorption band of the carbonate ions CO 32- was assigned at 871, 1416 and 1461 cm -1. X-ray diffraction and thermal analysis confirm the obtained results of FITR. Results showed that the main inorganic constituents of C. edulis and basil leaves are hydroxyapatite whereas the hydroxyapatite content in the other plant samples is less than that in case of C. edulis and basil plant leaves.

Room temperature chemical synthesis of lead selenide thin films with preferred orientation

NASA Astrophysics Data System (ADS)

Kale, R. B.; Sartale, S. D.; Ganesan, V.; Lokhande, C. D.; Lin, Yi-Feng; Lu, Shih-Yuan

2006-11-01

Room temperature chemical synthesis of PbSe thin films was carried out from aqueous ammoniacal solution using Pb(CH3COO)2 as Pb2+ and Na2SeSO3 as Se2- ion sources. The films were characterized by a various techniques including, X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), Fast Fourier transform (FFT) and UV-vis-NIR techniques. The study revealed that the PbSe thin film consists of preferentially oriented nanocubes with energy band gap of 0.5 eV.

Structural diversity of silver (I) azine complexes - Effect of substituents and counter anions

NASA Astrophysics Data System (ADS)

Patra, Goutam Kumar; Mukherjee, Anindita; Mitra, Partha; Adarsh, N. N.

2011-08-01

Three new Ag(I) complexes, 1, 2, and 3 of two azine ligands diacetyl dihydrazone ( L1) and benzil dihydrazone ( L2) have been synthesized and characterized by single crystal X-ray diffraction studies (for 2 and 3), X-ray powder diffraction studies( 1 and 2), elemental analyses, IR and UV-VIS spectroscopy and TGA analysis. They represent one-dimensional polymeric assemblies and discrete dinuclear Ag(I) complex depending on functionality of the ligands and the counter anions. Tetrahedral as well as square pyramidal coordination motifs of the silver (I) ions have been observed in the supramolecular designing of such hybrid organic-inorganic materials.

Microstructural characterization of Ti-6Al-4V alloy subjected to the duplex SMAT/plasma nitriding.

PubMed

Pi, Y; Faure, J; Agoda-Tandjawa, G; Andreazza, C; Potiron, S; Levesque, A; Demangel, C; Retraint, D; Benhayoune, H

2013-09-01

In this study, microstructural characterization of Ti-6Al-4V alloy, subjected to the duplex surface mechanical attrition treatment (SMAT)/nitriding treatment, leading to improve its mechanical properties, was carried out through novel and original samples preparation methods. Instead of acid etching which is limited for morphological characterization by scanning electron microscopy (SEM), an original ion polishing method was developed. Moreover, for structural characterization by transmission electron microscopy (TEM), an ion milling method based with the use of two ions guns was also carried out for cross-section preparation. To demonstrate the efficiency of the two developed methods, morphological investigations were done by traditional SEM and field emission gun SEM. This was followed by structural investigations through selected area electron diffraction (SAED) coupled with TEM and X-ray diffraction techniques. The results demonstrated that ionic polishing allowed to reveal a variation of the microstructure according to the surface treatment that could not be observed by acid etching preparation. TEM associated to SAED and X-ray diffraction provided information regarding the nanostructure compositional changes induced by the duplex SMAT/nitriding process. Copyright © 2013 Wiley Periodicals, Inc.

Human insulin polymorphism upon ligand binding and pH variation: the case of 4-ethylresorcinol.

PubMed

Fili, S; Valmas, A; Norrman, M; Schluckebier, G; Beckers, D; Degen, T; Wright, J; Fitch, A; Gozzo, F; Giannopoulou, A E; Karavassili, F; Margiolaki, I

2015-09-01

This study focuses on the effects of the organic ligand 4-ethylresorcinol on the crystal structure of human insulin using powder X-ray crystallography. For this purpose, systematic crystallization experiments have been conducted in the presence of the organic ligand and zinc ions within the pH range 4.50-8.20, while observing crystallization behaviour around the isoelectric point of insulin. High-throughput crystal screening was performed using a laboratory X-ray diffraction system. The most representative samples were selected for synchrotron X-ray diffraction measurements, which took place at the European Synchrotron Radiation Facility (ESRF) and the Swiss Light Source (SLS). Four different crystalline polymorphs have been identified. Among these, two new phases with monoclinic symmetry have been found, which are targets for the future development of microcrystalline insulin drugs.

Human insulin polymorphism upon ligand binding and pH variation: the case of 4-ethylresorcinol

PubMed Central

Fili, S.; Valmas, A.; Norrman, M.; Schluckebier, G.; Beckers, D.; Degen, T.; Wright, J.; Fitch, A.; Gozzo, F.; Giannopoulou, A. E.; Karavassili, F.; Margiolaki, I.

2015-01-01

This study focuses on the effects of the organic ligand 4-ethylresorcinol on the crystal structure of human insulin using powder X-ray crystallography. For this purpose, systematic crystallization experiments have been conducted in the presence of the organic ligand and zinc ions within the pH range 4.50–8.20, while observing crystallization behaviour around the isoelectric point of insulin. High-throughput crystal screening was performed using a laboratory X-ray diffraction system. The most representative samples were selected for synchrotron X-ray diffraction measurements, which took place at the European Synchrotron Radiation Facility (ESRF) and the Swiss Light Source (SLS). Four different crystalline polymorphs have been identified. Among these, two new phases with monoclinic symmetry have been found, which are targets for the future development of microcrystalline insulin drugs. PMID:26306195

Alkali-Resistant Mechanism of a Hollandite DeNOx Catalyst.

PubMed

Hu, Pingping; Huang, Zhiwei; Gu, Xiao; Xu, Fei; Gao, Jiayi; Wang, Yue; Chen, Yaxin; Tang, Xingfu

2015-06-02

A thorough understanding of the deactivation mechanism by alkalis is of great importance for rationally designing improved alkali-resistant deNOx catalysts, but a traditional ion-exchange mechanism cannot often accurately describe the nature of the deactivation, thus hampering the development of superior catalysts. Here, we establish a new exchange-coordination mechanism on the basis of the exhaustive study on the strong alkali resistance of a hollandite manganese oxide (HMO) catalyst. A combination of isothermal adsorption measurements of ammonia with X-ray absorption near-edge structure spectra and X-ray photoelectron spectra reveals that alkali metal ions first react with protons from Brønsted acid sites of HMO via the ion exchange. Synchrotron X-ray diffraction patterns and extended X-ray absorption fine structure spectra coupled with theoretical calculations demonstrate that the exchanged alkali metal ions are subsequently stabilized at size-suitable cavities in the HMO pores via a coordination model with an energy savings. This exchange-coordination mechanism not only gives a wholly convincing explanation for the intrinsic nature of the deactivation of the reported catalysts by alkalis but also provides a strategy for rationally designing improved alkali-resistant deNOx catalysts in general.

Effect Of Chromium Underlayer On The Properties Of Nano-Crystalline Diamond Films

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

Garratt, Elias; AlFaify, Salem; Yoshitake, T.

2013-01-11

This paper investigated the effect of chromium underlayer on the structure, microstructure and composition of the nano-crystalline diamond films. Nano-crystalline diamond thin films were deposited at high temperature in microwave-induced plasma diluted with nitrogen, on silicon substrate with a thin film of chromium as an underlayer. The composition, structure and microstructure of the deposited layers were analyzed using non-Rutherford Backscattering Spectrometry, Raman Spectroscopy, Near-Edge X-Ray Absorption Fine Structure, X-ray Diffraction and Atomic Force Microscopy. Nanoindentation studies showed that the films deposited on chromium underlayer have higher hardness values compared to those deposited on silicon without an underlayer. Diamond and graphiticmore » phases of the films evaluated by x-ray and optical spectroscopic analysis determined consistency between sp2 and sp3 phases of carbon in chromium sample to that of diamond grown on silicon. Diffusion of chromium was observed using ion beam analysis which was correlated with the formation of chromium complexes by x-ray diffraction.« less

Effect of chromium underlayer on the properties of nano-crystalline diamond films

NASA Astrophysics Data System (ADS)

Garratt, E.; AlFaify, S.; Yoshitake, T.; Katamune, Y.; Bowden, M.; Nandasiri, M.; Ghantasala, M.; Mancini, D. C.; Thevuthasan, S.; Kayani, A.

2013-01-01

This paper investigated the effect of chromium underlayer on the structure, microstructure, and composition of the nano-crystalline diamond films. Nano-crystalline diamond thin films were deposited at high temperature in microwave-induced plasma diluted with nitrogen, on single crystal silicon substrate with a thin film of chromium as an underlayer. Characterization of the film was implemented using non-Rutherford backscattering spectrometry, Raman spectroscopy, near-edge x-ray absorption fine structure, x-ray diffraction, and atomic force microscopy. Nanoindentation studies showed that the films deposited on chromium underlayer have higher hardness values compared to those deposited on silicon without an underlayer. Diamond and graphitic phases of the films evaluated by x-ray and optical spectroscopic analyses determined consistency between the sp2 and sp3 phases of carbon in chromium sample to that of diamond grown on silicon. Diffusion of chromium was observed using ion beam analysis which was correlated with the formation of chromium complexes by x-ray diffraction.

Structural and mechanical properties of hydroxyapatite coatings formed by ion-beam assisted deposition

NASA Astrophysics Data System (ADS)

Zykova, A.; Safonov, V.; Dudin, S.; Yakovin, S.; Donkov, N.; Ghaemi, M. H.; Szkodo, M.; Antoszkiewicz, M.; Szyfelbain, M.; Czaban, A.

2018-03-01

The ion-beam assisted deposition (IBAD) is an advanced method capable of producing crystalline coatings at low temperatures. We determined the characteristics of hydroxyapatite Ca10(PO4)6(OH)2 target and coatings formed by IBAD using X-ray photoemission spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray (EDX). The composition of the coatings’ cross-section and surface was close to those of the target. The XPS spectra showed that the binding energy values of Ca (2p1/2, 2p3/2), P (2p3/2), and O 1s levels are related to the hydroxyapatite phase. The coatings demonstrate an optimal H/E ratio, and a good resistance to scratch tests.

Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

DOEpatents

Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

2016-08-09

A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

Crystal Structure, Magnetic and Optical Properties of Mn-Doped BiFeO₃ by Hydrothermal Synthesis.

PubMed

Zhang, Ning; Wei, Qinhua; Qin, Laishun; Chen, Da; Chen, Zhi; Niu, Feng; Wang, Jiangying; Huanag, Yuexiang

2017-01-01

In this paper, Mn doped BiFeO₃ were firstly synthesized by hydrothermal process. The influence of Mn doping on structural, optical and magnetic properties of BiFeO₃ was studied. The different amounts of Mn doping in BiFeO₃ were characterized by X-ray diffraction, Scanning Electron Microscope, Energy Dispersive X-ray Spectroscope, UV-Vis diffuse reflectance spectroscopy and magnetic measurements. The X-ray diffraction (XRD) patterns confirmed the formation of pure phase rhombohedral structure in BiFe(1−x) Mn (x) O₃ (x = 0.01, 0.03, 0.05, 0.07) samples. The morphologies and chemical compositions of as-prepared samples could be observed by Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Spectroscope (EDS). A relative large saturated magnetization (Ms) of 0.53 emu/g for x = 0.07 sample was obtained at room temperature, which is considered to be Mn ions doping. UV-Vis diffuse reflectance spectroscopy showed strong absorption of light in the range of 200–1000 nm, indicating the optical band gap in the visible region for these samples. This implied that BiFe(1−x) Mn(x)O₃ may be a potential photocatalyst for utilizing solar energy.

Characterization of ion-induced radiation effects in nuclear materials using synchrotron x-ray techniques

DOE PAGES

Lang, Maik; Tracy, Cameron L.; Palomares, Raul I.; ...

2015-05-01

Recent efforts to characterize the nanoscale structural and chemical modifications induced by energetic ion irradiation in nuclear materials have greatly benefited from the application of synchrotron-based x-ray diffraction (XRD) and x-ray absorption spectroscopy (XAS) techniques. Key to the study of actinide-bearing materials has been the use of small sample volumes, which are particularly advantageous, as the small quantities minimize the level of radiation exposure at the ion-beam and synchrotron user facility. This approach utilizes energetic heavy ions (energy range: 100 MeV–3 GeV) that pass completely through the sample thickness and deposit an almost constant energy per unit length along theirmore » trajectory. High energy x-rays (25–65 keV) from intense synchrotron light sources are then used in transmission geometry to analyze ion-induced structural and chemical modifications throughout the ion tracks. We describe in detail the experimental approach for utilizing synchrotron radiation (SR) to study the radiation response of a range of nuclear materials (e.g., ThO 2 and Gd 2Ti xZr 2–xO 7). Also addressed is the use of high-pressure techniques, such as the heatable diamond anvil cell, as a new means to expose irradiated materials to well-controlled high-temperature (up to 1000 °C) and/or high-pressure (up to 50 GPa) conditions. Furthermore, this is particularly useful for characterizing the annealing kinetics of irradiation-induced material modifications.« less

Investigation of the Structural Stability of Ion-Implanted Gd 2Ti 2-xSn xO 7 Pyrochlore-Type Oxides by Glancing Angle X-ray Absorption Spectroscopy

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

Aluri, Esther Rani; Hayes, John R.; Walker, James D.S.

2016-03-24

Rare-earth titanate and stannate pyrochlore-type oxides have been investigated in the past for the sequestration of nuclear waste elements because of their resistance to radiation-induced structural damage. In order to enhance this property, it is necessary to understand the effect of radioactive decay of the incorporated actinide elements on the local chemical environment. In this study, Gd 2Ti 2–xSn xO 7 materials have been implanted with Au– ions to simulate radiation-induced structural damage. Glancing angle X-ray absorption near-edge spectroscopy (GA-XANES), glancing angle X-ray absorption fine structure (GA-EXAFS) analysis, and powder X-ray diffraction have been used to investigate changes in themore » local coordination environment of the metal atoms in the damaged surface layer. Examination of GA-XANES/EXAFS spectra from the implanted Gd 2Ti 2–xSn xO 7 materials collected at various glancing angles allowed for an investigation of how the local coordination environment around the absorbing atoms changed at different depths in the damaged surface layer. This study has shown the usefulness of GA-XANES to the examination of ion-implanted materials and has suggested that Gd 2Ti 2–xSn xO 7 becomes more susceptible to ion-beam-induced structural damage with increasing Sn concentration.« less

Preparation of γ-LiV2O5 from polyoxovanadate cluster Li7[V15O36(CO3)] as a high-performance cathode material and its reaction mechanism revealed by operando XAFS

NASA Astrophysics Data System (ADS)

Wang, Heng; Isobe, Jin; Shimizu, Takeshi; Matsumura, Daiju; Ina, Toshiaki; Yoshikawa, Hirofumi

2017-08-01

γ-phase LiV2O5, which shows superior electrochemical performance as cathode material in Li-ion batteries, was prepared by annealing the polyoxovanadate cluster Li7 [V15O36(CO3)]. The reaction mechanism was studied using operando X-ray absorption fine structure (XAFS), powder X-ray diffraction (PXRD), and X-ray photoelectron spectroscopy (XPS) analyses. The X-ray absorption near edge structure (XANES) and XPS results reveal that γ-LiV2O5 undergoes two-electron redox reaction per V2O5 pyramid unit, resulting in a large reversible capacity of 260 Ah/kg. The extended X-ray absorption fine structure (EXAFS) and PXRD analyses also suggest that the V-V distance slightly increases, due to the reduction of V5+ to V4+ during Li ion intercalation as the material structure is maintained. As a result, γ-LixV2O5 shows highly reversible electrochemical reaction with x = 0.1-1.9.

Valence, exchange interaction, and location of Mn ions in polycrystalline M n x G a 1 - x N ( x ≤ 0.04 )

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

Furrer, A.; Kramer, K. W.; Podlesnyak, A.

In this paper, we present an experimental study for polycrystalline samples of the diluted magnetic semiconductormore » $$\\mathrm{M}{\\mathrm{n}}_{x}\\mathrm{G}{\\mathrm{a}}_{1{-}x}\\mathrm{N}(x{\\le}0.04)$$ in order to address some of the existing controversial issues. X-ray and neutron diffraction, x-ray absorption near-edge structure, and electron paramagnetic resonance experiments were used to characterize the structural, electronic, and magnetic properties of the samples, and inelastic neutron scattering was employed to determine the magnetic excitations associated with Mn monomers and dimers. Our main conclusions are as follows: (i) The valence of the Mn ions is $2+$. (ii) The $$\\mathrm{M}{\\mathrm{n}}^{2+}$$ ions experience a substantial single-ion axial anisotropy with parameter D = 0.027(3) meV. (iii) Nearest-neighbor $$\\mathrm{M}{\\mathrm{n}}^{2+}$$ ions are coupled antiferromagnetically. Finally, the exchange parameter $$J={-}0.140(7)\\mathrm{meV}$$ is independent of the Mn content $x$; i.e., there is no evidence for hole-induced modifications of $J$ towards a potentially high Curie temperature postulated in the literature.« less

Valence, exchange interaction, and location of Mn ions in polycrystalline M n x G a 1 - x N ( x ≤ 0.04 )

DOE PAGES

Furrer, A.; Kramer, K. W.; Podlesnyak, A.; ...

2018-04-10

In this paper, we present an experimental study for polycrystalline samples of the diluted magnetic semiconductormore » $$\\mathrm{M}{\\mathrm{n}}_{x}\\mathrm{G}{\\mathrm{a}}_{1{-}x}\\mathrm{N}(x{\\le}0.04)$$ in order to address some of the existing controversial issues. X-ray and neutron diffraction, x-ray absorption near-edge structure, and electron paramagnetic resonance experiments were used to characterize the structural, electronic, and magnetic properties of the samples, and inelastic neutron scattering was employed to determine the magnetic excitations associated with Mn monomers and dimers. Our main conclusions are as follows: (i) The valence of the Mn ions is $2+$. (ii) The $$\\mathrm{M}{\\mathrm{n}}^{2+}$$ ions experience a substantial single-ion axial anisotropy with parameter D = 0.027(3) meV. (iii) Nearest-neighbor $$\\mathrm{M}{\\mathrm{n}}^{2+}$$ ions are coupled antiferromagnetically. Finally, the exchange parameter $$J={-}0.140(7)\\mathrm{meV}$$ is independent of the Mn content $x$; i.e., there is no evidence for hole-induced modifications of $J$ towards a potentially high Curie temperature postulated in the literature.« less

Enhanced UVB emission and analysis of chemical states of Ca5(PO4)3OH:Gd3+,Pr3+ phosphor prepared by co-precipitation

NASA Astrophysics Data System (ADS)

Mokoena, P. P.; Nagpure, I. M.; Kumar, Vinay; Kroon, R. E.; Olivier, E. J.; Neethling, J. H.; Swart, H. C.; Ntwaeaborwa, O. M.

2014-08-01

Hydroxyapatite (Ca5(PO4)3OH) is a well-known bioceramic material used in medical applications because of its ability to form direct chemical bonds with living tissues. This mineral is currently used as a host for rare-earth ions (e.g. Gd3+, Pr3+, Tb3+, etc.) to prepare phosphors that can be used in light emitting devices of different types. In this study Ca5(PO4)3OH:Gd3+,Pr3+ phosphors were prepared by the co-precipitation method and were characterised by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive x-ray spectroscopy and photoluminescence spectroscopy. The x-ray diffraction pattern was consistent with the hexagonal phase of Ca5(PO4)3OH referenced in JCPDS card number 73-0293. The x-ray photoelectron spectroscopy data indicated that Ca2+ occupied two different lattice sites, referred to as Ca1 and Ca2. The photoluminescence data exhibited a narrowband emission located at 313 nm, which is associated with the 6P7/2→8S7/2 transition of the Gd3+ ion. This emission is classified as ultraviolet B and it is suitable for use in phototherapy lamps to treat various skin diseases. The photoluminescence intensity of the 313 nm emission was enhanced considerably by Pr3+ co-doping.

Insights from soft X-rays: the chlorine and sulfur sub-structures of a CK2alpha/DRB complex.

PubMed

Raaf, Jennifer; Issinger, Olaf-Georg; Niefind, Karsten

2008-09-01

The diffraction pattern of a protein crystal is normally a product of the interference of electromagnetic waves scattered by electrons of the crystalline sample. The diffraction pattern undergoes systematic changes in case additionally X-ray absorption occurs, meaning if the wavelength of the primary X-ray beam is relatively close to the absorption edge of selected elements of the sample. The resulting effects are summarized as "anomalous dispersion" and can be always observed with "soft" X-rays (wavelength around 2 A) since they match the absorption edges of sulfur and chlorine. A particularly useful application of this phenomenon is the experimental detection of the sub-structures of the anomalous scatterers in protein crystals. We demonstrate this here with a crystal of a C-terminally truncated variant of human CK2alpha to which two molecules of the inhibitor 5,6-dichloro-1-beta-D-ribo-furanosyl-benzimidazole (DRB) are bound. The structure of this co-crystal has been solved recently. For this study we measured an additional diffraction data set at a wavelength of 2 A which showed strong anomalous dispersion effects. On the basis of these effects we detected all sulfur atoms of the protein, the two liganded DRB molecules and a total of 16 additional chloride ions some of them emerging at positions filled with water molecules in previous structure determinations. A number of chloride ions are bound to structural and functional important locations fitting to the constitutive activity and the acidophilic substrate specificity of the enzyme.

Study of marbles from Middle Atlas (Morocco): elemental, mineralogical and structural analysis

NASA Astrophysics Data System (ADS)

Khrissi, S.; Bejjit, L.; Haddad, M.; Falguères, C.; Ait Lyazidi, S.; El Amraoui, M.

2018-05-01

A series of marbles sampled from the region of Middle Atlas (Morocco), are characterized by different complementary spectroscopic techniques. X-Ray fluorescence is used to determine elemental composition of rock while X-Ray diffraction and the Raman spectroscopy are used to determine major crystalline phases (calcite and dolomite) and minor ones (quartz).The samples display typical EPR spectra of Mn2+ in calcite and reveal the presence of Fe3+ ions.

Evaluation of Argon ion irradiation hardening of ferritic/martensitic steel-T91 using nanoindentation, X-ray diffraction and TEM techniques

NASA Astrophysics Data System (ADS)

Naveen Kumar, N.; Tewari, R.; Mukherjee, P.; Gayathri, N.; Durgaprasad, P. V.; Taki, G. S.; Krishna, J. B. M.; Sinha, A. K.; Pant, P.; Revally, A. K.; Dutta, B. K.; Dey, G. K.

2017-08-01

In the present study, microstructures of Ferritic-martensitic T-91 steel irradiated at room temperature for 5, 10 and 20 dpa using 315 KeV Ar+9 ions have been characterized by grazing incident X-ray diffraction (GIXRD) and by transmission electron microscopy (TEM). Line profiles of GIXRD patterns have shown that the size of domain continuously reduced with increasing dose of radiation. TEM investigations of irradiated samples have shown the presence of black dots, the number density of which decreases with increasing dose. Microstructures of irradiated samples have also revealed the presence of point defect clusters, such as dislocation loops and bubbles. In addition, dissolution of precipitates due to irradiation was also observed. Nano-indentation studies on the irradiated samples have shown saturation behavior in hardness as a function of dose which could be correlated with the changes in the yield strength of the alloy.

Sodium storage mechanisms of bismuth in sodium ion batteries: An operando X-ray diffraction study

NASA Astrophysics Data System (ADS)

Gao, Hui; Ma, Wensheng; Yang, Wanfeng; Wang, Jiawei; Niu, Jiazheng; Luo, Fakui; Peng, Zhangquan; Zhang, Zhonghua

2018-03-01

Understanding the sodium (Na) chemistry is crucial for development of high-performance sodium ion batteries (SIBs). Nanostructured bismuth (Bi) has shown great potentials as an anode in SIBs, however, the Na storage mechanisms of Bi are still unclear. Herein, the operando X-ray diffraction (XRD) technique was utilized to probe the Na storage mechanisms of three Bi anodes (sputtered Bi film, nanoporous Bi and commercial Bi). Despite different morphologies and sizes, all the Bi anodes follow the same two-step reversible alloying/dealloying mechanisms (Bi ↔ NaBi ↔ Na3Bi) during the discharge/charge processes, associated with two voltage plateaus. As for the intercalation/deintercalation mechanism proposed for nanostructured Bi anodes in SIBs, we rationalize the reason why only the Bi phase is detected in the discharged/charged samples under ex-situ XRD conditions through addressing the stability issue of the Na-Bi system (NaBi and Na3Bi).

Influence of yttrium content on the location of rare earth ions in LYSO:Ce crystals

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

Ding, Dongzhou, E-mail: dongzhou_ding@mail.sic.ac.cn; R and D Center of Shanghai Institute of Ceramics, No. 588 Heshuo Road, Shanghai 201899; Weng, Linhong

2014-01-15

Single-crystal X-ray diffraction (SCD), X-ray fluorescence (XRF), inductively coupled plasma optical emission spectroscopy (ICP-OES) and X-ray excited luminescence (XEL) measurements were performed to investigate structure details and segregation coefficients of (Lu{sub 1−x}Y{sub x}){sub 2}SiO{sub 5}:Ce (x=0 at%, 8.7 at%, 25.7 at%, 44.7 at%, 65.7 at%, 87.9 at% and 100 at%). Y{sup 3+} cations were found to have a preferential occupation for RE1 site (7-oxygen-coordinated) over RE2 site (6-oxygen-coordinated), which results in a greater increase of cell parameter c than that of a with increase in Y content due to LYSO's microstructure characteristics. Results presented here revealed that the less themore » difference in electronegativity and effective ionic radius between the two ions, the easier substitution of one ion by the other, and hence the higher segregation coefficients. Besides, the contribution of luminescence of Ce1 and Ce2 in the whole XEL was evaluated, and the location of Ce{sup 3+} ion was discussed. - Graphical abstract: Segregation coefficients of (Lu{sub 1−x}Y{sub x}){sub 2}SiO{sub 5}:Cce:italic> at RT/ce:italic>. Display Omitted.« less

Deposition of PTFE thin films by ion beam sputtering and a study of the ion bombardment effect

NASA Astrophysics Data System (ADS)

He, J. L.; Li, W. Z.; Wang, L. D.; Wang, J.; Li, H. D.

1998-02-01

Ion beam sputtering technique was employed to prepare thin films of Polytetrafluroethylene (PTFE). Simultaneous ion beam bombardment during film growth was also conducted in order to study the bombardment effects. Infrared absorption (IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis was used to evaluate the material's integrity. It was found that PTFE thin films could be grown at room temperature by direct sputtering of a PTFE target. The film's composition and structure were shown to be dependent on the sputtering energy. Films deposited by single sputtering at higher energy (˜1500 eV) were structurally quite similar to the original PTFE material. Simultaneous ion beam bombarding during film growth caused defluorination and structural changes. Mechanism for sputtering deposition of such a polymeric material is also discussed.

Investigation of Room temperature Ferromagnetism in Mn doped Ge

NASA Astrophysics Data System (ADS)

Colakerol Arslan, Leyla; Toydemir, Burcu; Onel, Aykut Can; Ertas, Merve; Doganay, Hatice; Gebze Inst of Tech Collaboration; Research Center Julich Collaboration

2014-03-01

We present a systematic investigation of structural, magnetic and electronic properties of MnxGe1 -x single crystals. MnxGe1-x films were grown by sequential deposition of Ge and Mn by molecular-beam epitaxy at low substrate temperatures in order to avoid precipitation of ferromagnetic Ge-Mn intermetallic compounds. Reflected high energy electron diffraction and x-ray diffraction observations revealed that films are epitaxially grown on Si (001) substrates from the initial stage without any other phase formation. Magnetic measurements carried out using a physical property measurement system showed that all samples exhibited ferromagnetism at room temperature. Electron spin resonance indicates the presence of magnetically ordered localized spins of divalent Mn ions. X-ray absorption measurements at the Mn L-edge confirm significant substitutional doping of Mn into Ge-sites. The ferromagnetism was mainly induced by Mn substitution for Ge site, and indirect exchange interaction of these magnetic ions with the intrinsic charge carriers is the origin of ferromagnetism. The magnetic interactions were better understood by codoping with nonmagnetic impurities. This work was supported by Marie-Curie Reintegration Grant (PIRG08-GA-2010-276973).

Effect of Cu2+ substitution on the structural, optical and magnetic behaviour ofchemically derived manganese ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Vasuki, G.; Balu, T.

2018-06-01

Mixed spinel copper manganese ferrite (CuXMn1‑XFe2O4, X = 0, 0.25, 0.5, 0.75, 1) nanoparticles were synthesized by chemical co-precipitation technique. From the powder x-ray diffraction analysis the lattice constant, volume of unit cell, x-ray density, hopping lengths, crystallite size, surface area, dislocation density and microstrain were calculated. The substitution of Cu2+ ions shows a considerable reduction in the crystallite size of manganese ferrite from 34 nm to 22 nm. Further a linear fit of Williamson-Hall plot has been drawn to determine the microstrain and crystallite size. The crystallite size and morphology were further observed through high resolution transmission electron microscope and scanning electron microscope. The diffraction rings observed from selected area electron diffraction pattern exhibits the crystalline nature of all the samples. The energy dispersive x-ray analysis shows the composition of all the elements incorporated in the synthesized nanomaterials. FTIR studies reveal the absorption peaks that correspond to the metal-oxygen vibrations in the tetrahedral and octahedral sites. From the UV–vis absorption spectra the band gap energy, refractive index and optical dielectric constant were determined. Magnetic studies carried out using vibrating sample magnetometer shows interesting behaviour in the variation of magnetisation and coercivity. Peculiar magnetic behaviour is observed when Cu2+ ions are substituted in manganese ferrites. All the synthesized materials have very low value of squareness ratio which attributes to the superparamagnetic behaviour.

Study of Early Transition Metal Carbides for Energy Storage Applications

NASA Astrophysics Data System (ADS)

Dall'Agnese, Yohan

An increase in energy and power density is needed to match the growing energy storage demands linked with the development of renewable energy production, and portable electronics. Several energy storage technologies exist including lithium-ion batteries, sodium-ion batteries, fuel cells and supercapacitors. These systems are mutually complementary. For example, supercapacitors can deliver high power densities whereas batteries can be used for high energy density applications. The first objective of this work was to investigate the electrochemical performances of a new family of 2-D materials called MXenes by cyclic voltammetry and galvanostatic charge-discharge measurements and to propose new solutions to tackle the energy storage concern. To achieve this goal, several directions have been explored. The first part of the research focused on Ti3C 2-based MXenes behavior as electrode materials for supercapacitors in aqueous electrolytes. The charge storage mechanisms in basic and neutral aqueous electrolytes, investigated by X-ray diffraction, were demonstrated to be attributed to cations intercalation between Ti3C2 layers. X-ray photoelectron spectroscopy highlighted the contribution of oxygenated functional groups on surface redox reactions in sulfuric acid. High capacitances were achieved, up to 520 F/cm3 and 325 F/g. Then the electrochemical behaviors of MXenes in sodium-based organic electrolytes were explored. A new hybrid system of sodium-ion capacitor was proposed. It was demonstrated that V2C-based MXene electrodes were suitable to be used as positive electrodes with an operating potential from 1 V to 3.5 V vs. Na+/Na. Continuous intercalation and de-intercalation of sodium ions between the V2C layers during sodiation and desodiation were showed by X-ray diffraction. An asymmetric sodium-ion capacitor full cell was assembled using hard carbon as negative electrode and showed promising results, with a capacity of 50 mAh/g. The last part was focused on the study of MXene electrodes for supercapacitors in an organic electrolyte; 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITFSI) in acetonitrile. High volumetric capacitances, up to 245 F/cm 3, were achieved by using carbon nanotubes as an additive to improve ion accessibility to Ti3C2 layers. The redox intercalation of large EMI+ cations between Ti3C2 layers at -0.4 V vs. Ag was observed by X-ray diffraction.

Detection of Reaction Intermediates in Mg2+-Dependent DNA Synthesis and RNA Degradation by Time-Resolved X-Ray Crystallography.

PubMed

Samara, Nadine L; Gao, Yang; Wu, Jinjun; Yang, Wei

2017-01-01

Structures of enzyme-substrate/product complexes have been studied for over four decades but have been limited to either before or after a chemical reaction. Recently using in crystallo catalysis combined with X-ray diffraction, we have discovered that many enzymatic reactions in nucleic acid metabolism require additional metal ion cofactors that are not present in the substrate or product state. By controlling metal ions essential for catalysis, the in crystallo approach has revealed unprecedented details of reaction intermediates. Here we present protocols used for successful studies of Mg 2+ -dependent DNA polymerases and ribonucleases that are applicable to analyses of a variety of metal ion-dependent reactions. © 2017 Elsevier Inc. All rights reserved.

The Preparation and Characterization of a Sodium Tungsten Bronze

ERIC Educational Resources Information Center

Conroy, Lawrence E.

1977-01-01

Describes an experiment that utilizes the techniques of temperature synthesis, crystallization from a molten salt, oxidation-reduction in a molten salt, powder X-ray diffraction and analysis by high temperature volatilization or a specific ion electrode. (MLH)

Structural, magnetic and Mössbauer studies of Nd-doped Mg-Mn ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Somnath; Sharma, Indu; Kotnala, R. K.; Singh, M.; Kumar, Arun; Dhiman, Pooja; Singh, Virender Pratap; Verma, Kartikey; Kumar, Gagan

2017-12-01

The present work is focused on the replacement of Fe3+ ions by rare-earth Nd3+ ions and their influence on the cations distribution, structural, magnetic and Mössbauer properties of Mg-Mn nanoferrites. Nanosized Nd-doped Mg-Mn nanoferrites, Mg0.9Mn0.1NdxFe2-xO4, where x = 0.1, 0.2 & 0.3, were successfully synthesized for the first time through solution combustion technique. X-ray diffraction studies confirmed the formation of single phase nature of the synthesized nanoferrites. Williamsons-Hall plots were used to obtain the particle size and strain while the lattice parameter was obtained from Nelson-Riley plots. The particle size was observed to decrease (19.2-13.5 nm) while lattice parameter was observed to increase (8.373-8.391 Å) with the incorporation of Nd3+ ions. Cation distribution between the tetrahedral (A-site) and octahedral (B-site) was estimated by using the X-ray diffraction method & magnetization technique. The estimated cation distribution was used to investigate the detailed structural parameters. Room temperature M-H study revealed a decrease of saturation magnetization (10.15-1.83 emu/g) and an increase in coercivity (22.86-27.19 Oe) with the increasing substitution of Nd3+ ions. Magnetic results obtained in the present study indicated that the synthesized nanoferrites can be a useful candidate for electromagnet applications.

[Structure and luminescence properties of Ga2O3 : Cr3+ by Al doping].

PubMed

Wang, Xian-Sheng; Wan, Min-Hua; Wang, Yin-Hai; Zhao, Hui; Hu, Zheng-Fa; Li, Hai-Ling

2013-11-01

The Al doping gallate phosphor (Ga(1-x)Al(x))2O3 : Cr3+ (x = 0, 0.1, 0.2, 0.3, 0.4, 0.5) was synthesized by a high temperature solid-state reaction method. The X-ray diffractions show that the phase of the phosphors remains to be Ga2 O3 structure with increase in the contents of Al3+ ion. Beside, the fact that the X-ray diffraction peak shifts towards big angles with increasing Al3+ ions content shows that Al3+ ions entered the Ga2 O3 lattice. The peaks of the excitation spectra located at 258, 300, 410 and 550 nm are attributed to the band to band transition of the matrix, charge transfer band transition, and 4A2 --> 4T1 and 4A2 --> 4T2 transition of Cr3+ ions, respectively. Those excitation spectrum peak positions show different degrees of blue shift with the increase in the Al3+ ions content. The blue shift of the first two peaks are due to the band gap energy of substrate and the electronegativity between Cr3+ ions and ligands increasing, respectively. The blue shift of the energy level transition of Cr3+ ion is attributed to crystal field strength increasing. The Cr3+ ion luminescence changes from a broadband emission to a narrow-band emission with Al3+ doping, because the emission of Cr3+ ion changed from 4 T2 --> 4A2 to 2E --> 4A2 transition with the crystal field change after Al3+ ions doping. The Al3+ ions doping improved the long afterglow luminescence properties of samples, and the sample showed a longer visible near infrared when Al3+ ions content reaches 0.5. The thermoluminescence curve shows the sample with suitable trap energy level, and this is also the cause of the long afterglow luminescence materials.

Existence of Fe{sup 4+} ions in Co{sub 2.25}Fe{sub 0.75}O{sub 4} spinel ferrite confirmed from SXRD and XANES spectroscopy

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

Panda, Manas Ranjan, E-mail: manasranjan056@gmail.com; Bhowmik, R. N.; Sinha, A. K.

2015-06-24

The Co{sub 2.25}Fe{sub 0.75}O{sub 4} ferrite composition has been prepared by chemical co-precipitation route. The as-prepared sample after annealing at 900°C in air formed single phase cubic spinel structure. Synchrotron X-ray diffraction and X-ray absorption near edge structure (XANES) measurements were used to study charge states of the cations in octahedral and tetrahedral sites of the cubic spinel structure. Raman spectra indicated normal cubic spinel structure. XANES data suggested the existence of Fe{sup 4+} ions in the spinel structure.

Room temperature synthesis of Cu₂O nanospheres: optical properties and thermal behavior.

PubMed

Nunes, Daniela; Santos, Lídia; Duarte, Paulo; Pimentel, Ana; Pinto, Joana V; Barquinha, Pedro; Carvalho, Patrícia A; Fortunato, Elvira; Martins, Rodrigo

2015-02-01

The present work reports a simple and easy wet chemistry synthesis of cuprous oxide (Cu2O) nanospheres at room temperature without surfactants and using different precursors. Structural characterization was carried out by X-ray diffraction, transmission electron microscopy, and scanning electron microscopy coupled with focused ion beam and energy-dispersive X-ray spectroscopy. The optical band gaps were determined from diffuse reflectance spectroscopy. The photoluminescence behavior of the as-synthesized nanospheres showed significant differences depending on the precursors used. The Cu2O nanospheres were constituted by aggregates of nanocrystals, in which an on/off emission behavior of each individual nanocrystal was identified during transmission electron microscopy observations. The thermal behavior of the Cu2O nanospheres was investigated with in situ X-ray diffraction and differential scanning calorimetry experiments. Remarkable structural differences were observed for the nanospheres annealed in air, which turned into hollow spherical structures surrounded by outsized nanocrystals.

Controlled vapor crystal growth of N a4I r3O8 : A three-dimensional quantum spin liquid candidate

NASA Astrophysics Data System (ADS)

Zheng, Hong; Zhang, Junjie; Stoumpos, Constantinos C.; Ren, Yang; Chen, Yu-Sheng; Dally, Rebecca; Wilson, Stephen D.; Islam, Zahirul; Mitchell, J. F.

2018-04-01

We report the successful bulk single-crystal growth of the hyperkagome lattice iridate N a4I r3O8 (Na438) by vapor transport using a sealed aluminum oxide tube as a container. Crystals were characterized by magnetization, x-ray diffraction, and energy-dispersive x-ray measurements, confirming their identity and properties. Single-crystal x-ray diffraction experiments revealed superlattice peaks indexed on a propagation vector q =(1 /3 ,1 /3 ,1 /3 ) based on the cubic substructure with cell parameter a =8.986 (1 )Å . This superlattice is three-dimensional and fully coherent. Polarization analysis rules out spin and/or orbital order as the underlying origin of the modulation and points to long-range ordering of Na ions at the notionally disordered Na sites as a plausible origin for the observed superlattice.

Magnetic properties of Fe-doped NiO nanoparticles

NASA Astrophysics Data System (ADS)

Kurokawa, A.; Sakai, N.; Zhu, L.; Takeuchi, H.; Yano, S.; Yanoh, T.; Onuma, K.; Kondo, T.; Miike, K.; Miyasaka, T.; Ichiyanagi, Y.

2013-08-01

Ni1- x Fe x O ( x = 0, 0.05, 0.1) nanoparticles with several nanometers encapsulated with amorphous SiO2 were prepared by our novel preparation method. A NiO single phase structure was confirmed using the X-ray diffraction measurements. It is considered that Ni ions are replaced by Fe ions because it is observed that the lattice constant decreases. The temperature dependence behavior of the magnetization revealed that the blocking temperature, T B , shifted from 17 to 57 K as the amount of Fe ions increased, and that below T B , ferromagnetic behaviors were exhibited. The coercive force, H C , increased from 0.8 to 1.5 kOe as the amount of Fe ions increased.

Ion-pairing in aqueous CaCl 2 and RbBr solutions. Simultaneous structural refinement of XAFS and XRD data

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

Pham, Thai V.; Fulton, John L.

2013-01-22

We present a new methodology involving the simultaneous refinement of both x-ray absorption and x-ray diffraction spectra (X-ray Absorption/Diffraction Structural Refinement,XADSR), to study hydration and ion pair structure of CaCl 2 and RbBr salts in concentrated aqueous solutions. The XADSR analysis includes the XAFS spectra analysis of both the cation and anion as a probe of their short-range structure with an XRD spectral analysis as a probe of the global structural. Together they deliver a comprehensive picture of the cation and anion hydration, the contact ion pair (CIP) structure and the solvent-separated ion pair (SSIP) structure. XADSR analysis of 6.0more » m aqueous CaCl 2 reveals that there are an insignificant number of Ca 2+-Cl- CIP’s, but there are approximately 3.4 SSIP’s separated by about 4.99 Å. In contrast XADSR analysis of aqueous RbBr yields about 0.7 pair CIP at a bond length 3.51 Å. The present work demonstrates a new approach for a direct co-refinement of XRD and XAFS spectra in a simple and reliable fashion, opening new opportunities for analysis in various disordered and crystalline systems. This work was supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences. Pacific Northwest National Laboratory (PNNL) is operated for the U.S. Department of Energy by Battelle.« less

Radiation induced deposition of copper nanoparticles inside the nanochannels of poly(acrylic acid)-grafted poly(ethylene terephthalate) track-etched membranes

NASA Astrophysics Data System (ADS)

Korolkov, Ilya V.; Güven, Olgun; Mashentseva, Anastassiya A.; Atıcı, Ayse Bakar; Gorin, Yevgeniy G.; Zdorovets, Maxim V.; Taltenov, Abzal A.

2017-01-01

Poly(ethylene terephthalate) PET, track-etched membranes (TeMs) with 400 nm average pore size were UV-grafted with poly(acrylic acid) (PAA) after oxidation of inner surfaces by H2O2/UV system. Carboxylate groups of grafted PAA chains were easily complexed with Cu2+ ions in aqueous solutions. These ions were converted into metallic copper nanoparticles (NPs) by radiation-induced reduction of copper ions in aqueous-alcohol solution by gamma rays in the dose range of 46-250 kGy. Copper ions chelating with -COOH groups of PAA chains grafted on PET TeMs form polymer-metal ion complex that prevent the formation of agglomerates during reduction of copper ions to metallic nanoparticles. The detailed analysis by X-Ray diffraction technique (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed the deposition of copper nanoparticles with the average size of 70 nm on the inner surface of nanochannels of PET TeMs. Samples were also investigated by FTIR, ESR spectroscopies to follow copper ion reduction.

Effect of Co2+ and Y3+ ions insertion on the microstructure development and magnetic properties of Ni0.5Zn0.5Fe2O4 powders synthesized using Co-precipitation method

NASA Astrophysics Data System (ADS)

Rashad, M. M.; Rayan, D. A.; Turky, A. O.; Hessien, M. M.

2015-01-01

Nanocrystalline Ni0.5Zn0.5-xCoxFe2-zYzO4 powders (x=0-0.3 and z from 0 to 0.3) have been synthesized via a facile co-precipitation technique. X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM) are utilized in order to study the effect of variation of cobalt and yttrium substitutions and its impact on crystalline size, lattice parameter, X-ray density, microstructure and magnetic properties of the formed powders. X-ray diffraction data indicated that, after doping, all samples consisted of the main spinel phase for the formed precursors precipitated at pH 10 annealed at 1000 oC for 2 h. The lattice parameter and the unit cell were decreased linearly with increasing Co content whereas they were increased with increasing the Y incorporation. Additionally, the porosity was increased with increasing Co concentration while it was decreased with increasing the Y insertion. The mean ionic radii and hopping and bond lengths was decreased with the value of Co2+ and they were increased with the value of Y3+ ion as well as both of Y3+ and Co2+ ions. The microstructures of the produced powders were found to be cubic like structure. The addition of Y3+ ion suppressed the grain size whereas addition of Co2+ ion enhanced the grain growth availably. An examination of the magnetic properties revealed an increase in saturation magnetization with increasing Co and Y concentrations incorporation up to x=0.3. Meanwhile, the formed powders exhibited superparamagnetic characteristics. A high saturation magnetization (77.0 emu/g) was achieved for Ni0.5Zn0.2Co0.3Fe2O4 sample annealed at 1000 oC for 2 h.

Operando Grazing Incidence Small-Angle X-ray Scattering/X-ray Diffraction of Model Ordered Mesoporous Lithium-Ion Battery Anodes

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

Bhaway, Sarang M.; Qiang, Zhe; Xia, Yanfeng

Emergent lithium-ion (Li +) batteries commonly rely on nanostructuring of the active electrode materials to decrease the Li + ion diffusion path length and to accommodate the strains associated with the insertion and de-insertion of Li +, but in many cases these nanostructures evolve during electrochemical charging–discharging. This change in the nanostructure can adversely impact performance, and challenges remain regarding how to control these changes from the perspective of morphological design. In order to address these questions, operando grazing-incidence small-angle X-ray scattering and X-ray diffraction (GISAXS/GIXD) were used to assess the structural evolution of a family of model ordered mesoporousmore » NiCo 2O 4 anode films during battery operation. The pore dimensions were systematically varied and appear to impact the stability of the ordered nanostructure during the cycling. For the anodes with small mesopores (≈9 nm), the ordered nanostructure collapses during the first two charge–discharge cycles, as determined from GISAXS. This collapse is accompanied by irreversible Li-ion insertion within the oxide framework, determined from GIXD and irreversible capacity loss. Anodes with larger ordered mesopores (17–28 nm) mostly maintained their nanostructure through the first two cycles with reversible Li-ion insertion. During the second cycle, there was a small additional deformation of the mesostructure. Furthermore, this preservation of the ordered structure lead to significant improvement in capacity retention during these first two cycles; but, a gradual loss in the ordered nanostructure from continuing deformation of the ordered structure during additional charge–discharge cycles leads to capacity decay in battery performance. We translate these multiscale operando measurements provide insight into how changes at the atomic scale (lithium insertion and de-insertion) to the nanostructure during battery operation. Moreover, small changes in the nanostructure can build up to significant morphological transformations that adversely impact battery performance through multiple charge–discharge cycles.« less

Operando Grazing Incidence Small-Angle X-ray Scattering/X-ray Diffraction of Model Ordered Mesoporous Lithium-Ion Battery Anodes

DOE PAGES

Bhaway, Sarang M.; Qiang, Zhe; Xia, Yanfeng; ...

2017-02-07

Emergent lithium-ion (Li +) batteries commonly rely on nanostructuring of the active electrode materials to decrease the Li + ion diffusion path length and to accommodate the strains associated with the insertion and de-insertion of Li +, but in many cases these nanostructures evolve during electrochemical charging–discharging. This change in the nanostructure can adversely impact performance, and challenges remain regarding how to control these changes from the perspective of morphological design. In order to address these questions, operando grazing-incidence small-angle X-ray scattering and X-ray diffraction (GISAXS/GIXD) were used to assess the structural evolution of a family of model ordered mesoporousmore » NiCo 2O 4 anode films during battery operation. The pore dimensions were systematically varied and appear to impact the stability of the ordered nanostructure during the cycling. For the anodes with small mesopores (≈9 nm), the ordered nanostructure collapses during the first two charge–discharge cycles, as determined from GISAXS. This collapse is accompanied by irreversible Li-ion insertion within the oxide framework, determined from GIXD and irreversible capacity loss. Anodes with larger ordered mesopores (17–28 nm) mostly maintained their nanostructure through the first two cycles with reversible Li-ion insertion. During the second cycle, there was a small additional deformation of the mesostructure. Furthermore, this preservation of the ordered structure lead to significant improvement in capacity retention during these first two cycles; but, a gradual loss in the ordered nanostructure from continuing deformation of the ordered structure during additional charge–discharge cycles leads to capacity decay in battery performance. We translate these multiscale operando measurements provide insight into how changes at the atomic scale (lithium insertion and de-insertion) to the nanostructure during battery operation. Moreover, small changes in the nanostructure can build up to significant morphological transformations that adversely impact battery performance through multiple charge–discharge cycles.« less

Operando Grazing Incidence Small-Angle X-ray Scattering/X-ray Diffraction of Model Ordered Mesoporous Lithium-Ion Battery Anodes.

PubMed

Bhaway, Sarang M; Qiang, Zhe; Xia, Yanfeng; Xia, Xuhui; Lee, Byeongdu; Yager, Kevin G; Zhang, Lihua; Kisslinger, Kim; Chen, Yu-Ming; Liu, Kewei; Zhu, Yu; Vogt, Bryan D

2017-02-28

Emergent lithium-ion (Li + ) batteries commonly rely on nanostructuring of the active electrode materials to decrease the Li + ion diffusion path length and to accommodate the strains associated with the insertion and de-insertion of Li + , but in many cases these nanostructures evolve during electrochemical charging-discharging. This change in the nanostructure can adversely impact performance, and challenges remain regarding how to control these changes from the perspective of morphological design. In order to address these questions, operando grazing-incidence small-angle X-ray scattering and X-ray diffraction (GISAXS/GIXD) were used to assess the structural evolution of a family of model ordered mesoporous NiCo 2 O 4 anode films during battery operation. The pore dimensions were systematically varied and appear to impact the stability of the ordered nanostructure during the cycling. For the anodes with small mesopores (≈9 nm), the ordered nanostructure collapses during the first two charge-discharge cycles, as determined from GISAXS. This collapse is accompanied by irreversible Li-ion insertion within the oxide framework, determined from GIXD and irreversible capacity loss. Conversely, anodes with larger ordered mesopores (17-28 nm) mostly maintained their nanostructure through the first two cycles with reversible Li-ion insertion. During the second cycle, there was a small additional deformation of the mesostructure. This preservation of the ordered structure lead to significant improvement in capacity retention during these first two cycles; however, a gradual loss in the ordered nanostructure from continuing deformation of the ordered structure during additional charge-discharge cycles leads to capacity decay in battery performance. These multiscale operando measurements provide insight into how changes at the atomic scale (lithium insertion and de-insertion) are translated to the nanostructure during battery operation. Moreover, small changes in the nanostructure can build up to significant morphological transformations that adversely impact battery performance through multiple charge-discharge cycles.

Characterization of biogenic ferrihydrite nanoparticles by means of SAXS, SRD and IBA methods

NASA Astrophysics Data System (ADS)

Balasoiu, M.; Kichanov, S.; Pantelica, A.; Pantelica, D.; Stolyar, S.; Iskhakov, R.; Aranghel, D.; Ionescu, P.; Badita, C. R.; Kurkin, S.; Orelovich, O.; Tiutiunikov, S.

2018-03-01

Investigations of biogenic ferrihydrite nanoparticles produced by bacteria Klebsiella oxytoca by applying small angle X-ray scattering, synchrotron radiation diffraction and ion beam analysis methods are reviewed. Different experimental data processing methods are used and analyzed.

Recombination-enhanced surface expansion of clusters in intense soft x-ray laser pulses

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

Rupp, Daniela; Flückiger, Leonie; Adolph, Marcus

Here, we studied the nanoplasma formation and explosion dynamics of single large xenon clusters in ultrashort, intense x-ray free-electron laser pulses via ion spectroscopy. The simultaneous measurement of single-shot diffraction images enabled a single-cluster analysis that is free from any averaging over the cluster size and laser intensity distributions. The measured charge state-resolved ion energy spectra show narrow distributions with peak positions that scale linearly with final ion charge state. These two distinct signatures are attributed to highly efficient recombination that eventually leads to the dominant formation of neutral atoms in the cluster. The measured mean ion energies exceed themore » value expected without recombination by more than an order of magnitude, indicating that the energy release resulting from electron-ion recombination constitutes a previously unnoticed nanoplasma heating process. This conclusion is supported by results from semiclassical molecular dynamics simulations.« less

Heavy doping of CdTe single crystals by Cr ion implantation

NASA Astrophysics Data System (ADS)

Popovych, Volodymyr D.; Böttger, Roman; Heller, Rene; Zhou, Shengqiang; Bester, Mariusz; Cieniek, Bogumil; Mroczka, Robert; Lopucki, Rafal; Sagan, Piotr; Kuzma, Marian

2018-03-01

Implantation of bulk CdTe single crystals with high fluences of 500 keV Cr+ ions was performed to achieve Cr concentration above the equilibrium solubility limit of this element in CdTe lattice. The structure and composition of the implanted samples were studied using secondary ion mass spectrometry (SIMS), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD) and Rutherford backscattering spectrometry (RBS) to characterize the incorporation of chromium into the host lattice and to investigate irradiation-induced damage build-up. It was found that out-diffusion of Cr atoms and sputtering of the targets alter the depth distribution and limit concentration of the projectile ions in the as-implanted samples. Appearance of crystallographically oriented, metallic α-Cr nanoparticles inside CdTe matrix was found after implantation, as well as a strong disorder at the depth far beyond the projected range of the implanted ions.

Recombination-enhanced surface expansion of clusters in intense soft x-ray laser pulses

DOE PAGES

Rupp, Daniela; Flückiger, Leonie; Adolph, Marcus; ...

2016-10-07

Here, we studied the nanoplasma formation and explosion dynamics of single large xenon clusters in ultrashort, intense x-ray free-electron laser pulses via ion spectroscopy. The simultaneous measurement of single-shot diffraction images enabled a single-cluster analysis that is free from any averaging over the cluster size and laser intensity distributions. The measured charge state-resolved ion energy spectra show narrow distributions with peak positions that scale linearly with final ion charge state. These two distinct signatures are attributed to highly efficient recombination that eventually leads to the dominant formation of neutral atoms in the cluster. The measured mean ion energies exceed themore » value expected without recombination by more than an order of magnitude, indicating that the energy release resulting from electron-ion recombination constitutes a previously unnoticed nanoplasma heating process. This conclusion is supported by results from semiclassical molecular dynamics simulations.« less

Sensitivity and Limitations of Structures from X-ray and Neutron-Based Diffraction Analyses of Transition Metal Oxide Lithium-Battery Electrodes

DOE PAGES

Liu, Hao; Liu, Haodong; Lapidus, Saul H.; ...

2017-06-21

Lithium transition metal oxides are an important class of electrode materials for lithium-ion batteries. Binary or ternary (transition) metal doping brings about new opportunities to improve the electrode’s performance and often leads to more complex stoichiometries and atomic structures than the archetypal LiCoO 2. Rietveld structural analyses of X-ray and neutron diffraction data is a widely-used approach for structural characterization of crystalline materials. But, different structural models and refinement approaches can lead to differing results, and some parameters can be difficult to quantify due to the inherent limitations of the data. Here, through the example of LiNi 0.8Co 0.15Al 0.05Omore » 2 (NCA), we demonstrated the sensitivity of various structural parameters in Rietveld structural analysis to different refinement approaches and structural models, and proposed an approach to reduce refinement uncertainties due to the inexact X-ray scattering factors of the constituent atoms within the lattice. Furthermore, this refinement approach was implemented for electrochemically-cycled NCA samples and yielded accurate structural parameters using only X-ray diffraction data. The present work provides the best practices for performing structural refinement of lithium transition metal oxides.« less

Sensitivity and Limitations of Structures from X-ray and Neutron-Based Diffraction Analyses of Transition Metal Oxide Lithium-Battery Electrodes

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

Liu, Hao; Liu, Haodong; Lapidus, Saul H.

Lithium transition metal oxides are an important class of electrode materials for lithium-ion batteries. Binary or ternary (transition) metal doping brings about new opportunities to improve the electrode’s performance and often leads to more complex stoichiometries and atomic structures than the archetypal LiCoO 2. Rietveld structural analyses of X-ray and neutron diffraction data is a widely-used approach for structural characterization of crystalline materials. But, different structural models and refinement approaches can lead to differing results, and some parameters can be difficult to quantify due to the inherent limitations of the data. Here, through the example of LiNi 0.8Co 0.15Al 0.05Omore » 2 (NCA), we demonstrated the sensitivity of various structural parameters in Rietveld structural analysis to different refinement approaches and structural models, and proposed an approach to reduce refinement uncertainties due to the inexact X-ray scattering factors of the constituent atoms within the lattice. Furthermore, this refinement approach was implemented for electrochemically-cycled NCA samples and yielded accurate structural parameters using only X-ray diffraction data. The present work provides the best practices for performing structural refinement of lithium transition metal oxides.« less

Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and 7Li nuclear magnetic resonance studies of n-C x H(2 x+1)OSO3Li ( x = 12, 14, 16, 18, and 20)

NASA Astrophysics Data System (ADS)

Hirakawa, Satoru; Morimoto, Yoshiaki; Honda, Hisashi

2015-04-01

Electrical conductivity ( σ), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C x H (2 x+1) OSO 3Li ( x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, σ, DSC, and XRD observations of n-C x H (2 x+1) OSO 3Na and n-C x H (2 x+1) OSO 3K ( x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (Δ S). For n-C 18 H 37 OSO 3Li and n-C 20 H 41 OSO 3Li salts, each melting point produced a small Δ S mp value compared with the total entropy change in the solid phases (Δ S tr1+Δ S tr2). Additionally, Li + ion diffusion was detected in the highest temperature solid phases. For K salts, larger σ values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. 7Li NMR spectra of n-C 18 H 37 OSO 3Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li + ions are localized at asymmetric sites in the crystals.

Hydrothermal synthesis and characterization of hydroxyapatite and fluorhydroxyapatite nano-size powders.

PubMed

Montazeri, Leila; Javadpour, Jafar; Shokrgozar, Mohammad Ali; Bonakdar, Shahin; Javadian, Sayfoddin

2010-08-01

Pure hydroxyapatite (HAp) and fluoride-containing apatite powders (FHAp) were synthesized using a hydrothermal method. The powders were assessed by x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and F-selective electrode. X-ray diffraction results revealed the formation of single phase apatite structure for all the compositions synthesized in this work. However, the addition of a fluoride ion led to a systematic shift in the (3 0 0) peak of the XRD pattern as well as modifications in the FTIR spectra. It was found that the efficiency of fluoride ion incorporation decreased with the increase in the fluoride ion content. Fluorine incorporation efficiency was around 60% for most of the FHAp samples prepared in the current study. Smaller and less agglomerated particles were obtained by fluorine substitution. The bioactivity of the powder samples with different fluoride contents was compared by performing cell proliferation, alkaline phosphatase (ALP) and Alizarin red staining assays. Human osteoblast cells were used to assess the cellular responses to the powder samples in this study. Results demonstrated a strong dependence of different cell activities on the level of fluoridation.

Refinement of the crystal structure of the high-temperature phase G0 in (NH4)2WO2F4 (powder, x-ray, and neutron scattering)

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

Novak, D. M.; Smirnov, Lev S; Kolesnikov, Alexander I

2013-01-01

The (NH4)2WO2F4 compound undergoes a series of phase transitions: G0 -> 201 K -> G1 -> 160 K -> G2, with a significant change in entropy ( S1 ~ Rln10 at the G0 -> G1 transition), which indicates significant orientational disordering in the G0 phase and the order disorder type of the phase transition. X-ray diffraction is used to identify the crystal structure of the G0 phase as rhombohedral (sp. gr. Cmcm, Z = 4), determine the lattice parameters and the positions of all atoms (except hydrogen), and show that [WO2F4]2 ions can form a superposition of dynamic and staticmore » orientational disorders in the anionic sublattice. A determination of the orientational position of [NH4]+ ions calls for the combined method of elastic and inelastic neutron scattering. Inelastic neutron scattering is used to determine the state of hindered rotation for ammonium ions in the G0 phase. Powder neutron diffraction shows that the orientational disorder of NH4 ions can adequately be described within the free rotation approximation.« less

Influence of Fe ions on structural, optical and thermal properties of SnO{sub 2} nanoparticles

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

Ahmed, Ateeq, E-mail: ateeqamu124@gmail.com; Tripathi, P.; Khan, Wasi

2016-05-23

In the present work, Fe doped SnO{sub 2} nanoparticles with the composition Sn{sub 1-x}Fe{sub x}O{sub 2} (x = 0, 0.02, 0.04 and 0.06) have been successfully synthesized using sol-gel auto combustion technique. The samples are characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDAX), Ultraviolet (UV-Visible) absorption spectroscopy and thermal gravimetric analysis (TGA). The XRD study shows that all the samples have been found in tetragonal rutile structure without any extra phase and average crystallite size which lies in the range of 6-17 nm. The EDAX spectrum confirmed the doping of Fe ion into tin oxidemore » nanomaterial. The optical band gap of doped SnO{sub 2} is found to decrease with increasing Fe ion concentration, which is due to the formation of donor energy levels in the actual band gap of SnO{sub 2}.« less

Micro X-ray diffraction analysis of thin films using grazing-exit conditions.

PubMed

Noma, T; Iida, A

1998-05-01

An X-ray diffraction technique using a hard X-ray microbeam for thin-film analysis has been developed. To optimize the spatial resolution and the surface sensitivity, the X-ray microbeam strikes the sample surface at a large glancing angle while the diffracted X-ray signal is detected with a small (grazing) exit angle. Kirkpatrick-Baez optics developed at the Photon Factory were used, in combination with a multilayer monochromator, for focusing X-rays. The focused beam size was about 10 x 10 micro m. X-ray diffraction patterns of Pd, Pt and their layered structure were measured. Using a small exit angle, the signal-to-background ratio was improved due to a shallow escape depth. Under the grazing-exit condition, the refraction effect of diffracted X-rays was observed, indicating the possibility of surface sensitivity.

Grazing incidence x-ray diffraction analysis of zeolite NaA membranes on porous alumina tubes.

PubMed

Kyotani, Tomohiro

2006-07-01

Zeolite NaA-type membranes hydrothermally synthesized on porous alumina tubes, for dehydration process, were characterized by grazing incidence 2 theta scan X-ray diffraction analysis (GIXRD). The fine structure of the membrane was studied fractionally for surface layer and for materials embedded in the porous alumina tube. The thickness of the surface layer on the porous alumina tube in the membranes used in this study was approximately 2-3 microm as determined from transmission electron microscopy with focused ion beam thin-layer specimen preparation technique (FIB-TEM). To discuss the effects of the membrane surface morphology on the GIXRD measurements, CaA-type membrane prepared by ion exchange from the NaA-type membrane and surface-damaged NaA-type membrane prepared by water leaching were also studied. For the original NaA-type membrane, 2 theta scan GIXRD patterns could be clearly measured at X-ray incidence angles (alpha) ranging from 0.1 to 2.0 deg in increments of 0.1 deg. The surface layers of the 2 - 3 microm on the porous alumina tube correspond to the alpha values up to ca. 0.2 deg. For the CaA-type and the surface-damaged NaA-type membranes, however, diffraction patterns from the surface layer could not be successfully detected and the others were somewhat broad. For all the three samples, diffraction intensities of both zeolite and alumina increased with depth (X-ray incidence angle, alpha) in the porous alumina tube region. The depth profile analysis of the membranes based on the GIXRD first revealed that amount of zeolite crystal embedded in the porous alumina tube is much larger than that in the surface layer. Thus, the 2 theta scan GIXRD is a useful method to study zeolite crystal growth mechanism around (both inside and outside) the porous alumina support during hydrothermal synthesis and to study water permeation behavior in the dehydration process.

Characterization of Sb-doped Bi(2)UO(6) solid solutions by X-ray diffraction and X-ray absorption spectroscopy.

PubMed

Misra, N L; Yadav, A K; Dhara, Sangita; Mishra, S K; Phatak, Rohan; Poswal, A K; Jha, S N; Sinha, A K; Bhattacharyya, D

2013-01-01

The preparation and characterization of Sb-doped Bi(2)UO(6) solid solutions, in a limited composition range, is reported for the first time. The solid solutions were prepared by solid-state reactions of Bi(2)O(3), Sb(2)O(3) and U(3)O(8) in the required stoichiometry. The reaction products were characterized by X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) measurements at the Bi and U L(3) edges. The XRD patterns indicate the precipitation of additional phases in the samples when Sb doping exceeds 4 at%. The chemical shifts of the Bi absorption edges in the samples, determined from the XANES spectra, show a systematic variation only up to 4 at% of Sb doping and support the results of XRD measurements. These observations are further supported by the local structure parameters obtained by analysis of the EXAFS spectra. The local structure of U is found to remain unchanged upon Sb doping indicating that Sb(+3) ions replace Bi(+3) during the doping of Bi(2)UO(6) by Sb.

Room-temperature synthesis and photoluminescence of hexagonal CePO4 nanorods

NASA Astrophysics Data System (ADS)

Zhu, J.; Zhang, K.; Zhao, H. Y.

2018-01-01

Hexagonal CePO4 nanorods were synthesized via a simple chemical precipitation route at room-temperature without the presence of surfactants and then characterized by powder X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible (UV-vis) absorption and photoluminescence (PL) spectroscopy. Hexagonal CePO4 nanorods exhibit strong ultraviolet absorption and ultraviolet luminescence, which correspond to the electronic transitions between 4f and 5d state of Ce3+ ions.

Efficient and selective heavy metal sequestration from water by using layered sulfide K 2x Sn 4-x S 8-x (x = 0.65–1; KTS-3)

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

Sarma, Debajit; Islam, Saiful M.; Subrahmanyam, K. S.

Heavy metal ions (Cd 2+, Hg 2+, As 3+ and Pb 2+) are an important contributor to the contamination of groundwater and other water bodies in and around industrial areas. Herein, we demonstrate the rapid and efficient capacity of a layered metal sulfide material, K2xSn4-xS8-x (x = 0.65-1, KTS-3) for heavy metal ion removal from water. The effect of concentration, pH, kinetics, and competitive ions such as Na +/Ca 2+ on the heavy metal ion removal capacity of KTS-3 was systematically investigated. X-ray photoelectron spectroscopy (XPS), elemental analyses, and powder X-ray diffraction studies revealed that the heavy metal ion-exchange ofmore » KTS-3 is complete (quantitative replacement of all potassium ions) and topotactic. The heavy metal ion-exchange by using KTS-3 follows the Langmuir-Freundlich model with high exchange capacities, q(m) 205(17) mg g -1 for Cd 2+, 372(21) mg g -1 for Hg 2+ and 391(89) mg g -1 for Pb 2+. KTS-3 retains excellent heavy metal ion-exchange capacity even in very high concentration (1 M) of competing ions (Na +/Ca 2+) and also over a broad pH range (2-12). KTS-3 also exhibits very good ion-exchange capacity for precious Ag + and toxic As 3+ ions. The kinetics of heavy metal ion adsorption by KTS-3 are rapid (absorbs all ions within a few minutes). These properties and the environmentally friendly character of KTS-3 make it a promising candidate for sequestration of heavy metal ions from water.« less

Effects of X-ray irradiation on the Eu3+ → Eu2+ conversion in CaAl2O4 phosphors

NASA Astrophysics Data System (ADS)

Gomes, Manassés A.; Carvalho, Jéssica C.; Andrade, Adriano B.; Rezende, Marcos V.; Macedo, Zélia S.; Valerio, Mário E. G.

2018-01-01

This paper reports structural and luminescence properties of Eu-doped CaAl2O4 produced by an alternative sol-gel method using coconut water. Results of differential thermal analysis (DTA), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) allowed us to identify the best synthesis conditions for sample preparation. Simultaneous measurements of X-ray absorption spectroscopy (XAS) and X-ray excited optical luminescence (XEOL) were also performed in the X-ray energy range of the Eu LIII edge. Results from photoluminescence (PL) showed only the characteristic Eu3+ emission. However, radioluminescence emission spectra from Eu-doped CaAl2O4 shows a process of conversion of Eu3+ to Eu2+, which is induced by X-ray irradiation and is dependent on the radiation dose energy. X-ray absorption near edge structure (XANES) measurements corroborate Eu reduction due to irradiation, showing that only the Eu3+ ion is present in stable form in the CaAl2O4.

Ultrathin IBAD MgO films for epitaxial growth on amorphous substrates and sub-50 nm membranes

DOE PAGES

Wang, Siming; Antonakos, C.; Bordel, C.; ...

2016-11-07

Here, a fabrication process has been developed for high energy ion beam assisted deposition (IBAD) biaxial texturing of ultrathin (~1 nm) MgO films, using a high ion-to-atom ratio and post-deposition annealing instead of a homoepitaxial MgO layer. These films serve as the seed layer for epitaxial growth of materials on amorphous substrates such as electron/X-ray transparent membranes or nanocalorimetry devices. Stress measurements and atomic force microscopy of the MgO films reveal decreased stress and surface roughness, while X-ray diffraction of epitaxial overlayers demonstrates the improved crystal quality of films grown epitaxially on IBAD MgO. The process simplifies the synthesis ofmore » IBAD MgO, fundamentally solves the “wrinkle” issue induced by the homoepitaxial layer on sub-50 nm membranes, and enables studies of epitaxial materials in electron/X-ray transmission and nanocalorimetry.« less

A Potential Waste to be Selected as Media for Metal and Nutrient Removal

NASA Astrophysics Data System (ADS)

Zayadi, N.; Othman, N.; Hamdan, R.

2016-07-01

This study describes the potential of application of cassava peel, banana peel, coconut shell, and coconut coir to be selected as metal removal while limestone and steel slag for nutrient removal. The media were characterized by X-Ray Fluorescence (XRF), Fourier Transform Infrared (FTIR), Field Emission Scanning Electron Microscopy-Energy Dispersive X-Ray (FESEM-EDX), and X-Ray Powder Diffraction (XRD). The results of XRF analysis medias show the present of calcium oxide, CaO which confirm the high efficiency in adsorbing metal ions and nutrient which is in agreement with the result of XRD. The characteristics of medias by FTIR analysis also confirmed the involvement of alcohol, carboxylic, alkanes, amines and ethers which play important role to reduce ions while FESEM-EDX indicates the porous structures of study medias. The characterization analysis highlight that cassava peel and steel slag were selected as a potential media in this study.

Simultaneous Pressure-Induced Magnetic and Valence Transitions in Type-I Clathrate Eu8Ga16Ge30

NASA Astrophysics Data System (ADS)

Onimaru, Takahiro; Tsutsui, Satoshi; Mizumaki, Masaichiro; Kawamura, Naomi; Ishimatsu, Naoki; Avila, Marcos A.; Yamamoto, Shuhei; Yamane, Haruki; Suekuni, Koichiro; Umeo, Kazunori; Kume, Tetsuji; Nakano, Satoshi; Takabatake, Toshiro

2014-01-01

We have performed X-ray magnetic circular dichroism (XMCD) and X-ray absorption spectroscopy (XAS) measurements at pressures up to 17 GPa for the clathrate Eu8Ga16Ge30 (Curie temperature TC = 36 K). The temperature dependence of the XMCD spectra agrees well with that of the DC magnetization at ambient pressure. The TC is gradually enhanced with increasing pressures up to 13.3 GPa, and the divalent state of the Eu ions with J = 7/2 remains stable, but at 17 GPa the XMCD intensity is strongly suppressed and a spectral weight corresponding to the trivalent state of Eu ions (with no magnetic moment) appears in the XAS spectrum. The concurrent change from the type-I clathrate structure to an amorphous phase has been observed by X-ray diffraction experiment. We conclude that the amorphization of this compound induces the mixed valence state, which collapses the ferromagnetism.

Evidence for calcium soaps in human hair shaft revealed by sub-micrometer X-ray fluorescence

NASA Astrophysics Data System (ADS)

Briki, F.; Mérigoux, C.; Sarrot-Reynauld, F.; Salomé, M.; Fayard, B.; Susini, J.; Doucet, J.

2003-03-01

New information about calcium status in human scalp hair shaft, deduced from X-ray microfluorescence imaging, including its distribution over the hair section, the existence of one or several binding-types and its variation between people, is presented. The existence of two different calcium types is inferred. The first one corresponds to atoms (or ions) easily removable by hydrochloric acid, located in the cortex (granules), in the cuticle zone and also in the core of the medulla, which are identified as calcium soaps cy comparison with X-ray diffraction and IR spectromicroscopy data. The second type consists of non-easily removable calcium atoms (or ions) that are located in the medulla wall, probably also the cuticle, and rather uniformly in the cortex; these calcium atoms may be involved in Ca^{2+}-binding proteins, their concentration is fairly constant from one subject to another.

Structure of semiconducting versus fast-ion conducting glasses in the Ag-Ge-Se system.

PubMed

Zeidler, Anita; Salmon, Philip S; Whittaker, Dean A J; Piarristeguy, Andrea; Pradel, Annie; Fischer, Henry E; Benmore, Chris J; Gulbiten, Ozgur

2018-01-01

The transition from a semiconductor to a fast-ion conductor with increasing silver content along the Ag x (Ge 0.25 Se 0.75 ) (100- x ) tie line (0≤ x ≤25) was investigated on multiple length scales by employing a combination of electric force microscopy, X-ray diffraction, and neutron diffraction. The microscopy results show separation into silver-rich and silver-poor phases, where the Ag-rich phase percolates at the onset of fast-ion conductivity. The method of neutron diffraction with Ag isotope substitution was applied to the x =5 and x =25 compositions, and the results indicate an evolution in structure of the Ag-rich phase with change of composition. The Ag-Se nearest-neighbours are distributed about a distance of 2.64(1) Å, and the Ag-Se coordination number increases from 2.6(3) at x =5 to 3.3(2) at x =25. For x =25, the measured Ag-Ag partial pair-distribution function gives 1.9(2) Ag-Ag nearest-neighbours at a distance of 3.02(2) Å. The results show breakage of Se-Se homopolar bonds as silver is added to the Ge 0.25 Se 0.75 base glass, and the limit of glass-formation at x ≃28 coincides with an elimination of these bonds. A model is proposed for tracking the breakage of Se-Se homopolar bonds as silver is added to the base glass.

Structural and spectral properties of MgZnO2:Sm3+ phosphor

NASA Astrophysics Data System (ADS)

Rajput, Preasha; Sharma, Pallavi; Biswas, Pankaj; Kamni

2018-05-01

The samarium doped MgZnO2 phosphor was synthesized by the low-cost combustion method. The powder X-ray diffraction (XRD) analysis confirmed the crystallinity and phase purity of the phosphor. The lattice parameters were determined by indexing the diffraction peaks. The photoluminescence (PL) study revealed that the phosphor exhibited a broad excitation band in the UV region ranging between 200 to 350 nm. The 601 nm emission was ascribed to 4G5/2 to 6H7/2 transitions of the Sm3+ ion. The optical bandgap of MgZnO2:Sm3+ was obtained to be 3.56 eV. The phosphor can be projected as a useful material in X- and gamma-ray scintillators.

Size dependent behavior of Fe 3O 4 crystals during electrochemical (de)lithiation: an in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, transmission electron microscopy and theoretical investigation

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

Bock, David C.; Pelliccione, Christopher J.; Zhang, Wei

Here, the iron oxide magnetite, Fe 3O 4, is a promising conversion type lithium ion battery anode material due to its high natural abundance, low cost and high theoretical capacity. While the close packing of ions in the inverse spinel structure of Fe 3O 4 enables high energy density, it also limits the kinetics of lithium ion diffusion in the material. Nanosizing of Fe 3O 4 to reduce the diffusion path length is an effective strategy for overcoming this issue and results in improved rate capability. However, the impact of nanosizing on the multiple structural transformations that occur during themore » electrochemical (de)lithiation reaction in Fe 3O 4 is poorly understood. In this study, the influence of crystallite size on the lithiation-conversion mechanisms in Fe 3O 4 is investigated using complementary X-ray techniques along with transmission electron microscopy (TEM) and continuum level simulations on electrodes of two different Fe 3O 4 crystallite sizes. In situ X-ray diffraction (XRD) measurements were utilized to track the changes to the crystalline phases during (de)lithiation. X-ray absorption spectroscopy (XAS) measurements at multiple points during the (de)lithiation processes provided local electronic and atomic structural information. Tracking the crystalline and nanocrystalline phases during the first (de)lithiation provides experimental evidence that (1) the lithiation mechanism is non-uniform and dependent on crystallite size, where increased Li + diffusion length in larger crystals results in conversion to Fe 0 metal while insertion of Li + into spinel-Fe 3O 4 is still occurring, and (2) the disorder and size of the Fe metal domains formed when either material is fully lithiated impacts the homogeneity of the FeO phase formed during the subsequent delithiation.« less

Size dependent behavior of Fe 3O 4 crystals during electrochemical (de)lithiation: an in situ X-ray diffraction, ex situ X-ray absorption spectroscopy, transmission electron microscopy and theoretical investigation

DOE PAGES

Bock, David C.; Pelliccione, Christopher J.; Zhang, Wei; ...

2017-07-17

Here, the iron oxide magnetite, Fe 3O 4, is a promising conversion type lithium ion battery anode material due to its high natural abundance, low cost and high theoretical capacity. While the close packing of ions in the inverse spinel structure of Fe 3O 4 enables high energy density, it also limits the kinetics of lithium ion diffusion in the material. Nanosizing of Fe 3O 4 to reduce the diffusion path length is an effective strategy for overcoming this issue and results in improved rate capability. However, the impact of nanosizing on the multiple structural transformations that occur during themore » electrochemical (de)lithiation reaction in Fe 3O 4 is poorly understood. In this study, the influence of crystallite size on the lithiation-conversion mechanisms in Fe 3O 4 is investigated using complementary X-ray techniques along with transmission electron microscopy (TEM) and continuum level simulations on electrodes of two different Fe 3O 4 crystallite sizes. In situ X-ray diffraction (XRD) measurements were utilized to track the changes to the crystalline phases during (de)lithiation. X-ray absorption spectroscopy (XAS) measurements at multiple points during the (de)lithiation processes provided local electronic and atomic structural information. Tracking the crystalline and nanocrystalline phases during the first (de)lithiation provides experimental evidence that (1) the lithiation mechanism is non-uniform and dependent on crystallite size, where increased Li + diffusion length in larger crystals results in conversion to Fe 0 metal while insertion of Li + into spinel-Fe 3O 4 is still occurring, and (2) the disorder and size of the Fe metal domains formed when either material is fully lithiated impacts the homogeneity of the FeO phase formed during the subsequent delithiation.« less

120 MeV Ni Ion beam induced modifications in poly (ethylene terephthalate) used in commercial bottled water

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

Kumar, Vijay; Sonkawade, R. G.; Ali, Yasir

2012-06-05

We report the effects of heavy ion irradiation on the optical, structural, and chemical properties of polyethylene terephthalate (PET) film used in commercial bottled water. PET bottles were exposed with 120 MeV Ni ions at fluences varying from 3 x 10{sup 10} to 3 x 10{sup 12} ion/cm{sup 2}. The modifications so induced were analyzed by using UV-Vis, X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. Substantial decrease in optical band gap is observed with the increase in ion fluence. In the FTIR spectra, most of bands are decreased due the degradation of the molecular structure. XRD measurements showmore » the decrease in peak intensity, which reflects the loss of crystallinity after irradiation.« less

X-ray diffraction from shock-loaded polycrystals.

PubMed

Swift, Damian C

2008-01-01

X-ray diffraction was demonstrated from shock-compressed polycrystalline metals on nanosecond time scales. Laser ablation was used to induce shock waves in polycrystalline foils of Be, 25-125 microm thick. A second laser pulse was used to generate a plasma x-ray source by irradiation of a Ti foil. The x-ray source was collimated to produce a beam of controllable diameter, which was directed at the Be sample. X-rays were diffracted from the sample, and detected using films and x-ray streak cameras. The diffraction angle was observed to change with shock pressure. The diffraction angles were consistent with the uniaxial (elastic) and isotropic (plastic) compressions expected for the loading conditions used. Polycrystalline diffraction will be used to measure the response of the crystal lattice to high shock pressures and through phase changes.

High T(sub c) superconductor/ferroelectric heterostructures

NASA Astrophysics Data System (ADS)

Ryder, Daniel F., Jr.

1994-12-01

Thin films of the ferroelectric perovskite, Ba(x) Sr(1-x) TiO3 (BST), were deposited on superconducting (100)YBa2Cu3O(x)(YBCO)/ (100)Yttria-stabilized zirconia(YSZ) substrates and (100)Si by ion-beam sputtering. Microstructural and compositional features of the ceramic bilayer were assessed by a combination of x-ray diffraction (XRD) and scanning electron microscopy. The films were smooth and featureless, and energy dispersive x-ray spectroscopy (EDX) data indicated that film composition closely matched target composition. XRD analysis showed that films deposited on YBCO substrates were highly c-axis textured, while the films deposited on (100)Si did not exhibit any preferred growth morphology. The superconducting properties of the YBCO substrate layer were maintained throughout the processing stages and, as such, it was demonstrated that ion beam sputtering is a viable method for the deposition of Ferroelectric/YBCO heterostructures.

Neutron and X-ray diffraction of plasma-sprayed zirconia-yttria thermal barrier coatings

NASA Technical Reports Server (NTRS)

Shankar, N. R.; Herman, H.; Singhal, S. P.; Berndt, C. C.

1984-01-01

ZrO2-7.8mol. pct. YO1.5, a fused powder, and ZrO2-8.7mol. pct. YO1.5, a prereacted powder, were plasma-sprayed onto steel substrates. Neutron diffraction and X-ray diffraction of the as-received powder, the powder plasma sprayed into water, as-sprayed coatings, and coatings heat-treated for 10 and 100 h were carried out to study phase transformations and ordering of the oxygen ions on the oxygen sublattice. The as-received fused powder has a much lower monoclinic percentage than does the pre-reacted powder, this resulting in a much lower monoclinic percentage in the coating. Heat treatment increases the percentages of the cubic and monoclinic phases, while decreasing the tetragonal content. An ordered tetragonal phase is detected by the presence of extra neutron diffraction peaks. These phase transformations and ordering will result in volume changes. The implications of these transformations on the performance of partially stabilized zirconia thermal barrier coatings is discussed.

X-ray diffraction analysis and in vitro characterization of the UAM2 protein from Oryza sativa

DOE PAGES

Welner, Ditte Hededam; Tsai, Alex Yi-Lin; DeGiovanni, Andy M.; ...

2017-03-29

The role of seemingly non-enzymatic proteins in complexes interconverting UDP-arabinopyranose and UDP-arabinofuranose (UDP-arabinosemutases; UAMs) in the plant cytosol remains unknown. To shed light on their function, crystallographic and functional studies of the seemingly non-enzymatic UAM2 protein from Oryza sativa (OsUAM2) were undertaken. Here, X-ray diffraction data are reported, as well as analysis of the oligomeric state in the crystal and in solution. OsUAM2 crystallizes readily but forms highly radiation-sensitive crystals with limited diffraction power, requiring careful low-dose vector data acquisition. Using size-exclusion chromatography, it is shown that the protein is monomeric in solution. Finally, limited proteolysis was employed to demonstratemore » DTT-enhanced proteolytic digestion, indicating the existence of at least one intramolecular disulfide bridge or, alternatively, a requirement for a structural metal ion.« less

Single-pulse x-ray diffraction using polycapillary optics for in situ dynamic diffraction

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

Maddox, B. R., E-mail: maddox3@llnl.gov; Akin, M. C., E-mail: akin1@llnl.gov; Teruya, A.

2016-08-15

Diagnostic use of single-pulse x-ray diffraction (XRD) at pulsed power facilities can be challenging due to factors such as the high flux and brightness requirements for diffraction and the geometric constraints of experimental platforms. By necessity, the x-ray source is usually positioned very close, within a few inches of the sample. On dynamic compression platforms, this puts the x-ray source in the debris field. We coupled x-ray polycapillary optics to a single-shot needle-and-washer x-ray diode source using a laser-based alignment scheme to obtain high-quality x-ray diffraction using a single 16 ns x-ray pulse with the source >1 m from themore » sample. The system was tested on a Mo sample in reflection geometry using 17 keV x-rays from a Mo anode. We also identified an anode conditioning effect that increased the x-ray intensity by 180%. Quantitative measurements of the x-ray focal spot produced by the polycapillary yielded a total x-ray flux on the sample of 3.3 ± 0.5 × 10{sup 7} molybdenum Kα photons.« less

Fabricating Blazed Diffraction Gratings by X-Ray Lithography

NASA Technical Reports Server (NTRS)

Mouroulis, Pantazis; Hartley, Frank; Wilson, Daniel

2004-01-01

Gray-scale x-ray lithography is undergoing development as a technique for fabricating blazed diffraction gratings. As such, gray-scale x-ray lithography now complements such other grating-fabrication techniques as mechanical ruling, holography, ion etching, laser ablation, laser writing, and electron-beam lithography. Each of these techniques offers advantages and disadvantages for implementing specific grating designs; no single one of these techniques can satisfy the design requirements for all applications. Gray-scale x-ray lithography is expected to be advantageous for making gratings on steeper substrates than those that can be made by electron-beam lithography. This technique is not limited to sawtooth groove profiles and flat substrates: various groove profiles can be generated on arbitrarily shaped (including highly curved) substrates with the same ease as sawtooth profiles can be generated on flat substrates. Moreover, the gratings fabricated by this technique can be made free of ghosts (spurious diffraction components attributable to small spurious periodicities in the locations of grooves). The first step in gray-scale x-ray lithography is to conformally coat a substrate with a suitable photoresist. An x-ray mask (see Figure 1) is generated, placed between the substrate and a source of collimated x-rays, and scanned over the substrate so as to create a spatial modulation in the exposure of the photoresist. Development of the exposed photoresist results in a surface corrugation that corresponds to the spatial modulation and that defines the grating surface. The grating pattern is generated by scanning an appropriately shaped x-ray area mask along the substrate. The mask example of Figure 1 would generate a blazed grating profile when scanned in the perpendicular direction at constant speed, assuming the photoresist responds linearly to incident radiation. If the resist response is nonlinear, then the mask shape can be modified to account for the nonlinearity and produce a desired groove profile. An example of grating grooves generated by this technique is shown in Figure 2. A maximum relative efficiency of 88 percent has been demonstrated.

Detailed investigation of Na2.24FePO4CO3 as a cathode material for Na-ion batteries

PubMed Central

Huang, Weifeng; Zhou, Jing; Li, Biao; Ma, Jin; Tao, Shi; Xia, Dingguo; Chu, Wangsheng; Wu, Ziyu

2014-01-01

Na-ion batteries are gaining an increased recognition as the next generation low cost energy storage devices. Here, we present a characterization of Na3FePO4CO3 nanoplates as a novel cathode material for sodium ion batteries. First-principles calculations reveal that there are two paths for Na ion migration along b and c axis. In-situ and ex-situ Fe K-edge X-ray absorption near edge structure (XANES) point out that in Na3FePO4CO3 both Fe2+/Fe3+ and Fe3+/Fe4+ redox couples are electrochemically active, suggesting also the existence of a two-electron intercalation reaction. Ex-situ X-ray powder diffraction data demonstrates that the crystalline structure of Na3FePO4CO3 remains stable during the charging/discharging process within the range 2.0–4.55 V. PMID:24595232

A facile synthesis of zinc oxide/multiwalled carbon nanotube nanocomposite lithium ion battery anodes by sol-gel method

NASA Astrophysics Data System (ADS)

Köse, Hilal; Karaal, Şeyma; Aydın, Ali Osman; Akbulut, Hatem

2015-11-01

Free standing zinc oxide (ZnO) and multiwalled carbon nanotube (MWCNT) nanocomposite materials are prepared by a sol gel technique giving a new high capacity anode material for lithium ion batteries. Free-standing ZnO/MWCNT nanocomposite anodes with two different chelating agent additives, triethanolamine (TEA) and glycerin (GLY), yield different electrochemical performances. Field emission gun scanning electron microscopy (FEG-SEM), energy dispersive X-ray spectrometer (EDS), high resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analyses reveal the produced anode electrodes exhibit a unique structure of ZnO coating on the MWCNT surfaces. Li-ion cell assembly using a ZnO/MWCNT/GLY free-standing anode and Li metal cathode possesses the best discharge capacity, remaining as high as 460 mAh g-1 after 100 cycles. This core-shell structured anode can offer increased energy storage and performance over conventional anodes in Li-ion batteries.

Adsorption Studies of Gadolinium ion on Graphitic Carbon Nitride

NASA Astrophysics Data System (ADS)

Kuila, S. K.; Kundu, T. K.

2018-03-01

Bulk graphitic carbon nitride (g-C3N4) is synthesized by thermal decomposition of urea and used as an adsorbent for gadolinium ion (Gd3+) from aqueous solution. Adsorption capacity of g-C3N4 is found to be influenced by initial Gd3+ concentration, solution pH and contact time. Adsorbed Gd3+is separated from g-C3N4 by ultracentrifuge. Initial and Gd ion accumulated g-C3N4 adsorbent are characterized by X-ray diffraction technique (XRD) for phase identification, UV-visible and Fourier transform infrared (FTIR) spectroscopy for adsorption characteristics and optical property, scanning electron microscopy (SEM) for morphological behaviour along with energy dispersive X-ray spectroscopy (EDS) for elemental study. HNO3(0.1M), NaOH (0.1M) and de-ionized water are used for desorption and around 97% quantitative recovery of Gd ion is observed.

Structural study of Mg doped cobalt ferrite thin films on ITO coated glass substrate

NASA Astrophysics Data System (ADS)

Suthar, Mahesh; Bapna, Komal; Kumar, Kishor; Ahuja, B. L.

2018-05-01

We have synthesized thin films of Co1-xMgxFe2O4 (x = 0, 0.4, 0.6, 0.8, 1) on transparent conducting indium tin oxide (ITO) coated glass substrate by pulsed laser deposition method. The structural properties of the grown films were analyzed by the X-ray diffraction and Raman spectroscopy, which suggest the single phase growth of these films. Raman spectra revealed the incorporation of Mg ions into CoFe2O4 lattice and suggest that the Mg ions initially go both to the octahedral and tetrahedral sites upto a certain concentration. For higher concentration, Mg ions prefer to occupy the tetrahedral sites.

Pressure mapping for sphere and half-sphere enhanced diamond anvil cells using synchrotron x-ray diffraction and fluorescence techniques

NASA Astrophysics Data System (ADS)

Liu, H.; Liu, L. L.; Cai, Z.; Shu, J.

2015-12-01

The measurement for equation of state (EoS) of materials under pressure conditions above 200 GPa is a long-standing challenging subject. Recently, second stage anvil, which was loaded inside the diamond anvil cell (DAC), had been reported by various groups. This method could generate pressure over 300 GPa, or above 600 GPa from the EoS measurement of Re metal between the tiny anvil or 2 half-spheres. Several alternative approaches, using ruby balls, or glassy carbon, or diamond, with single sphere, 2 half-spheres, or multi spheres geometry inside DAC, were tested. The NIST X-ray powder standard, ZnO was selected as pressure marker. Focused ion beam (FIB) was used to cut the half-sphere from diamond anvil top directly to avoid the difficulty of alignment. The synchrotron x-ray diffraction with fine beam size down to 100 nm using zone plate set-up was used to map the pressure gradient at the sphere or half-sphere zone inside DAC. The pressure could be boosted at center of sphere by up to 10 - 70 GPa at about 200 GPa conditions. From broken anvils, trace element analysis using fine focusing synchrotron x-ray fluorescence method revealed the potential anvil damage from FIB cutting the diamond anvil tip, which might decrease the strength of anvils. Fine touch from FIB cutting at final stage using low ion beam current is suggested.

Ion beam modification of the structure and properties of hexagonal boron nitride: An infrared and X-ray diffraction study

NASA Astrophysics Data System (ADS)

Aradi, E.; Naidoo, S. R.; Billing, D. G.; Wamwangi, D.; Motochi, I.; Derry, T. E.

2014-07-01

The vibrational mode for the cubic symmetry of boron nitride (BN) has been produced by boron ion implantation of hexagonal boron nitride (h-BN). The optimum fluence at 150 keV was found to be 5 × 1014 ions/cm2. The presence of the c-BN phase was inferred using glancing incidence XRD (GIXRD) and Fourier Transform Infrared Spectroscopy (FTIR). After implantation, Fourier Transform Infrared Spectroscopy indicated a peak at 1092 cm-1 which corresponds to the vibrational mode for nanocrystalline BN (nc-BN). The glancing angle XRD pattern after implantation exhibited c-BN diffraction peaks relative to the implantation depth of 0.4 μm.

Effect of crystallographic orientation on structural and mechanical behaviors of Ni-Ti thin films irradiated by Ag7+ ions

NASA Astrophysics Data System (ADS)

Kumar, Veeresh; Singhal, Rahul

2018-04-01

In the present study, thin films of Ni-Ti shape memory alloy have been grown on Si substrate by dc magnetron co-sputtering technique using separate sputter targets Ni and Ti. The prepared thin films have been irradiated by 100 MeV Ag7+ ions at three different fluences, which are 1 × 1012, 5 × 1012, and 1 × 1013 ions/cm2. The elemental composition and depth profile of pristine film have been investigated by Rutherford backscattering spectrometry. The changes in crystal orientation, surface morphology, and mechanical properties of Ni-Ti thin films before and after irradiation have been studied by X-ray diffraction, atomic force microscopy, field-emission scanning electron microscopy, and nanoindentation techniques, respectively. X-ray diffraction measurement has revealed the existence of both austenite and martensite phases in pristine film and the formation of precipitate on the surface of the film after irradiation at an optimized fluence of 1 × 1013 ions/cm2. Nanoindentation measurement has revealed improvement in mechanical properties of Ni-Ti thin films after ion irradiation via increasing hardness and Young modulus due to the formation of precipitate and ductile phase. The improvement in mechanical behavior could be explained in terms of precipitation hardening and structural change of Ni-Ti thin film after irradiation by Swift heavy ion irradiation.

Local Structure Determination of Carbon/Nickel Ferrite Composite Nanofibers Probed by X-ray Absorption Spectroscopy.

PubMed

Nilmoung, Sukunya; Kidkhunthod, Pinit; Maensiri, Santi

2015-11-01

Carbon/NiFe2O4 composite nanofibers have been successfully prepared by electrospinning method using a various concentration solution of Ni and Fe nitrates dispersed into polyacrylonitride (PAN) solution in N,N' dimethylformamide. The phase and mophology of PAN/NiFe2O4 composite samples were characterized and investigated by X-ray diffraction and scanning electron microscopy. The magnetic properties of the prepared samples were measured at ambient temperature by a vibrating sample magnetometer. It is found that all composite samples exhibit ferromagnetism. This could be local-structurally explained by the existed oxidation states of Ni2+ and Fe3+ in the samples. Moreover, local environments around Ni and Fe ions could be revealed by X-ray absorption spectroscopy (XAS) measurement including X-ray absorption near edge structure (XANES) and Extended X-ray absorption fine structure (EXAFS).

Crystal Structure of Garnet-Related Li-Ion Conductor Li7–3xGaxLa3Zr2O12: Fast Li-Ion Conduction Caused by a Different Cubic Modification?

PubMed Central

2016-01-01

Li-oxide garnets such as Li7La3Zr2O12 (LLZO) are among the most promising candidates for solid-state electrolytes to be used in next-generation Li-ion batteries. The garnet-structured cubic modification of LLZO, showing space group Ia-3d, has to be stabilized with supervalent cations. LLZO stabilized with Ga3+ shows superior properties compared to LLZO stabilized with similar cations; however, the reason for this behavior is still unknown. In this study, a comprehensive structural characterization of Ga-stabilized LLZO is performed by means of single-crystal X-ray diffraction. Coarse-grained samples with crystal sizes of several hundred micrometers are obtained by solid-state reaction. Single-crystal X-ray diffraction results show that Li7–3xGaxLa3Zr2O12 with x > 0.07 crystallizes in the acentric cubic space group I-43d. This is the first definite record of this cubic modification for LLZO materials and might explain the superior electrochemical performance of Ga-stabilized LLZO compared to its Al-stabilized counterpart. The phase transition seems to be caused by the site preference of Ga3+. 7Li NMR spectroscopy indicates an additional Li-ion diffusion process for LLZO with space group I-43d compared to space group Ia-3d. Despite all efforts undertaken to reveal structure–property relationships for this class of materials, this study highlights the potential for new discoveries. PMID:27019548

Large-area soft x-ray projection lithography using multilayer mirrors structured by RIE

NASA Astrophysics Data System (ADS)

Rahn, Steffen; Kloidt, Andreas; Kleineberg, Ulf; Schmiedeskamp, Bernt; Kadel, Klaus; Schomburg, Werner K.; Hormes, F. J.; Heinzmann, Ulrich

1993-01-01

SXPL (soft X-ray projection lithography) is one of the most promising applications of X-ray reflecting optics using multilayer mirrors. Within our collaboration, such multilayer mirrors were fabricated, characterized, laterally structured and then used as reflection masks in a projecting lithography procedure. Mo/Si-multilayer mirrors were produced by electron beam evaporation in UHV under thermal treatment with an in-situ X-ray controlled thickness in the region of 2d equals 14 nm. The reflectivities measured at normal incidence reached up to 54%. Various surface analysis techniques have been applied in order to characterize and optimize the X-ray mirrors. The multilayers were patterned by reactive ion etching (RIE) with CF(subscript 4), using a photoresist as the etch mask, thus producing X-ray reflection masks. The masks were tested in the synchrotron radiation laboratory of the electron accelerator ELSA at the Physikalisches Institut of Bonn University. A double crystal X-ray monochromator was modified so as to allow about 0.5 cm(superscript 2) of the reflection mask to be illuminated by white synchrotron radiation. The reflected patterns were projected (with an energy of 100 eV) onto the resist (Hoechst AZ PF 514), which was mounted at an average distance of about 7 mm. In the first test-experiments, structure sizes down to 8 micrometers were nicely reproduced over the whole of the exposed area. Smaller structures were distorted by Fresnel-diffraction. The theoretically calculated diffraction images agree very well with the observed images.

Na-Ion Intercalation and Charge Storage Mechanism in Two-Dimensional Vanadium Carbide

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

Bak, Seong -Min; Qiao, Ruimin; Yang, W.

We synthesized two-dimensional vanadium carbide MXene containing surface functional groups (denoted as V 2CT x, where T x are surface functional groups) and studied as anode material for Na-ion batteries. V 2CT x anode exhibits reversible charge storage with good cycling stability and high rate capability through electrochemical test. Furthermore, the charge storage mechanism of V 2CT x material during Na + intercalation/deintercalation and the redox reaction of vanadium were studied using a combination of synchrotron based X-ray diffraction (XRD), hard X-ray absorption near edge spectroscopy (XANES) and soft X-ray absorption spectroscopy (sXAS). Experimental evidence of a major contribution ofmore » redox reaction of vanadium to the charge storage and the reversible capacity of V 2CT x during sodiation/desodiation process have been provided through V K-edge XANES and V L2,3-edge sXAS results. A correlation between the CO 3 2- content and Na + intercalation/deintercalation states in the V 2CT x electrode observed from C and O K-edge in sXAS results imply that some additional charge storage reactions may take place between the Na +-intercalated V 2CT x and the carbonate based non-aqueous electrolyte. Our results of this study will provide valuable information for the further studies on V 2CT x as anode material for Na-ion batteries and capacitors.« less

Na-Ion Intercalation and Charge Storage Mechanism in Two-Dimensional Vanadium Carbide

DOE PAGES

Bak, Seong -Min; Qiao, Ruimin; Yang, W.; ...

2017-07-14

We synthesized two-dimensional vanadium carbide MXene containing surface functional groups (denoted as V 2CT x, where T x are surface functional groups) and studied as anode material for Na-ion batteries. V 2CT x anode exhibits reversible charge storage with good cycling stability and high rate capability through electrochemical test. Furthermore, the charge storage mechanism of V 2CT x material during Na + intercalation/deintercalation and the redox reaction of vanadium were studied using a combination of synchrotron based X-ray diffraction (XRD), hard X-ray absorption near edge spectroscopy (XANES) and soft X-ray absorption spectroscopy (sXAS). Experimental evidence of a major contribution ofmore » redox reaction of vanadium to the charge storage and the reversible capacity of V 2CT x during sodiation/desodiation process have been provided through V K-edge XANES and V L2,3-edge sXAS results. A correlation between the CO 3 2- content and Na + intercalation/deintercalation states in the V 2CT x electrode observed from C and O K-edge in sXAS results imply that some additional charge storage reactions may take place between the Na +-intercalated V 2CT x and the carbonate based non-aqueous electrolyte. Our results of this study will provide valuable information for the further studies on V 2CT x as anode material for Na-ion batteries and capacitors.« less

X-Ray Diffraction Apparatus

NASA Technical Reports Server (NTRS)

Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

1996-01-01

An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

Structural and magnetic characterization of a tetranuclear copper(II) cubane stabilized by intramolecular metal cation-π interactions.

PubMed

Papadakis, Raffaello; Rivière, Eric; Giorgi, Michel; Jamet, Hélène; Rousselot-Pailley, Pierre; Réglier, Marius; Simaan, A Jalila; Tron, Thierry

2013-05-20

A novel tetranuclear copper(II) complex (1) was synthesized from the self-assembly of copper(II) perchlorate and the ligand N-benzyl-1-(2-pyridyl)methaneimine (L(1)). Single-crystal X-ray diffraction studies revealed that complex 1 consists of a Cu4(OH)4 cubane core, where the four copper(II) centers are linked by μ3-hydroxo bridges. Each copper(II) ion is in a distorted square-pyramidal geometry. X-ray analysis also evidenced an unusual metal cation-π interaction between the copper ions and phenyl substituents of the ligand. Calculations based on the density functional theory method were used to quantify the strength of this metal-π interaction, which appears as an important stabilizing parameter of the cubane core, possibly acting as a driving parameter in the self-aggregation process. In contrast, using the ligand N-phenethyl-1-(2-pyridyl)methaneimine (L(2)), which only differs from L(1) by one methylene group, the same synthetic procedure led to a binuclear bis(μ-hydroxo)copper(II) complex (2) displaying intermolecular π-π interactions or, by a slight variation of the experimental conditions, to a mononuclear complex (3). These complexes were studied by X-ray diffraction techniques. The magnetic properties of complexes 1 and 2 are reported and discussed.

Zn(1-x)MnxTe diluted magnetic semiconductor nanowires grown by molecular beam epitaxy.

PubMed

Zaleszczyk, Wojciech; Janik, Elzbieta; Presz, Adam; Dłuzewski, Piotr; Kret, Sławomir; Szuszkiewicz, Wojciech; Morhange, Jean-François; Dynowska, Elzbieta; Kirmse, Holm; Neumann, Wolfgang; Petroutchik, Aleksy; Baczewski, Lech T; Karczewski, Grzegorz; Wojtowicz, Tomasz

2008-11-01

It is shown that the growth of II-VI diluted magnetic semiconductor nanowires is possible by the catalytically enhanced molecular beam epitaxy (MBE). Zn(1-x)MnxTe NWs with manganese content up to x=0.60 were produced by this method. X-ray diffraction, Raman spectroscopy, and temperature dependent photoluminescence measurements confirm the incorporation of Mn(2+) ions in the cation substitutional sites of the ZnTe matrix of the NWs.

Effect of cobalt doping on the phase transformation of TiO2 nanoparticles.

PubMed

Barakat, M A; Hayes, G; Shah, S Ismat

2005-05-01

Co-doped TiO2 nanoparticles containing 0.0085, 0.017, 0.0255, 0.034, and 0.085 mol % Co(III) ion dopant were synthesized via sol-gel and dip-coating techniques. The effects of metal ion doping on the transformation of anatase to the rutile phase have been investigated. Several analytical tools, such as X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDAX) were used to investigate the nanoparticle structure, size distribution, and composition. Results obtained revealed that the rutile to anatase concentration ratio increases with increase of the cobalt dopant concentration and annealing temperature. The typical composition of Co-doped TiO2 was Ti(1-x)Co(x)O2, where x values ranged from 0.0085 to 0.085. The activation energy for the phase transformation from anatase to rutile was measured to be 229, 222, 211, and 195 kJ/mole for 0.0085, 0.017, 0.0255, and 0.034 mol % Co in TiO2, respectively.

Spectral properties of Dy3+ doped ZnAl2O4 phosphor

NASA Astrophysics Data System (ADS)

Prakash, Ram; Kumar, Sandeep; Mahajan, Rubby; Khajuria, Pooja; Kumar, Vinay; Choudhary, R. J.; Phase, D. M.

2018-05-01

Herein, Dy3+ doped ZnAl2O4 phosphor was synthesized by the solution combustion method. The synthesized phosphor was characterized by X-ray diffraction (XRD), photoluminescence (PL) spectroscopy, UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS). The phase purity of the phosphor was confirmed by the XRD studies that showed cubic symmetry of the synthesized phosphor. Under UV excitation (388 nm) the PL emission spectrum of the phosphor shows characteristic transition from the Dy3+ ion. A band gap of 5.2 eV was estimated from the diffused reflectance spectroscopy. The surface properties of the phosphor were studied using the X-ray photoelectron spectroscopy.

Real-time X-ray Diffraction: Applications to Materials Characterization

NASA Technical Reports Server (NTRS)

Rosemeier, R. G.

1984-01-01

With the high speed growth of materials it becomes necessary to develop measuring systems which also have the capabilities of characterizing these materials at high speeds. One of the conventional techniques of characterizing materials was X-ray diffraction. Film, which is the oldest method of recording the X-ray diffraction phenomenon, is not quite adequate in most circumstances to record fast changing events. Even though conventional proportional counters and scintillation counters can provide the speed necessary to record these changing events, they lack the ability to provide image information which may be important in some types of experiment or production arrangements. A selected number of novel applications of using X-ray diffraction to characterize materials in real-time are discussed. Also, device characteristics of some X-ray intensifiers useful in instantaneous X-ray diffraction applications briefly presented. Real-time X-ray diffraction experiments with the incorporation of image X-ray intensification add a new dimension in the characterization of materials. The uses of real-time image intensification in laboratory and production arrangements are quite unlimited and their application depends more upon the ingenuity of the scientist or engineer.

Operando X-ray Investigation of Electrode/Electrolyte Interfaces in Model Solid Oxide Fuel Cells

PubMed Central

2016-01-01

We employed operando anomalous surface X-ray diffraction to investigate the buried interface between the cathode and the electrolyte of a model solid oxide fuel cell with atomic resolution. The cell was studied under different oxygen pressures at elevated temperatures and polarizations by external potential control. Making use of anomalous X-ray diffraction effects at the Y and Zr K-edges allowed us to resolve the interfacial structure and chemical composition of a (100)-oriented, 9.5 mol % yttria-stabilized zirconia (YSZ) single crystal electrolyte below a La0.6Sr0.4CoO3−δ (LSC) electrode. We observe yttrium segregation toward the YSZ/LSC electrolyte/electrode interface under reducing conditions. Under oxidizing conditions, the interface becomes Y depleted. The yttrium segregation is corroborated by an enhanced outward relaxation of the YSZ interfacial metal ion layer. At the same time, an increase in point defect concentration in the electrolyte at the interface was observed, as evidenced by reduced YSZ crystallographic site occupancies for the cations as well as the oxygen ions. Such changes in composition are expected to strongly influence the oxygen ion transport through this interface which plays an important role for the performance of solid oxide fuel cells. The structure of the interface is compared to the bare YSZ(100) surface structure near the microelectrode under identical conditions and to the structure of the YSZ(100) surface prepared under ultrahigh vacuum conditions. PMID:27346923

Effect of gamma-irradiation on thermal decomposition kinetics, X-ray diffraction pattern and spectral properties of tris(1,2-diaminoethane)nickel(II)sulphate

NASA Astrophysics Data System (ADS)

Jayashri, T. A.; Krishnan, G.; Rema Rani, N.

2014-12-01

Tris(1,2-diaminoethane)nickel(II)sulphate was prepared, and characterised by various chemical and spectral techniques. The sample was irradiated with 60Co gamma rays for varying doses. Sulphite ion and ammonia were detected and estimated in the irradiated samples. Non-isothermal decomposition kinetics, X-ray diffraction pattern, Fourier transform infrared spectroscopy, electronic, fast atom bombardment mass spectra, and surface morphology of the complex were studied before and after irradiation. Kinetic parameters were evaluated by integral, differential, and approximation methods. Irradiation enhanced thermal decomposition, lowering thermal and kinetic parameters. The mechanism of decomposition is controlled by R3 function. From X-ray diffraction studies, change in lattice parameters and subsequent changes in unit cell volume and average crystallite size were observed. Both unirradiated and irradiated samples of the complex belong to trigonal crystal system. Decrease in the intensity of the peaks was observed in the infrared spectra of irradiated samples. Electronic spectral studies revealed that the M-L interaction is unaffected by irradiation. Mass spectral studies showed that the fragmentation patterns of the unirradiated and irradiated samples are similar. The additional fragment with m/z 256 found in the irradiated sample is attributed to S8+. Surface morphology of the complex changed upon irradiation.

Incorporation of Cadmium and Nickel into Ferrite Spinel Solid Solution: X-ray Diffraction and X-ray Absorption Fine Structure Analyses.

PubMed

Su, Minhua; Liao, Changzhong; Chan, Tingshan; Shih, Kaimin; Xiao, Tangfu; Chen, Diyun; Kong, Lingjun; Song, Gang

2018-01-16

The feasibility of incorporating Cd and Ni in hematite was studied by investigating the interaction mechanism for the formation of Cd x Ni 1-x Fe 2 O 4 solid solutions (CNFs) from CdO, NiO, and α-Fe 2 O 3 . X-ray diffraction results showed that the CNFs crystallized into spinel structures with increasing lattice parameters as the Cd content in the precursors was increased. Cd 2+ ions were found to occupy the tetrahedral sites, as evidenced by Rietveld refinement and extended X-ray absorption fine structure analyses. The incorporation of Cd and Ni into ferrite spinel solid solution strongly relied on the processing parameters. The incorporation of Cd and Ni into the CNFs was greater at high x values (0.7 < x ≤ 1.0) than at low x values (0.0 ≤ x ≤ 0.7). A feasible treatment technique based on the investigated mechanism of CNF formation was developed, involving thermal treatment of waste sludge containing Cd and Ni. Both of these metals in the waste sludge were successfully incorporated into a ferrite spinel solid solution, and the concentrations of leached Cd and Ni from this solid solution were substantially reduced, stabilizing at low levels. This research offers a highly promising approach for treating the Cd and Ni content frequently encountered in electronic waste and its treatment residues.

Radiation damage free ghost diffraction with atomic resolution

DOE PAGES

Li, Zheng; Medvedev, Nikita; Chapman, Henry N.; ...

2017-12-21

The x-ray free electron lasers can enable diffractive structural determination of protein nanocrystals and single molecules that are too small and radiation-sensitive for conventional x-ray diffraction. However the electronic form factor may be modified during the ultrashort x-ray pulse due to photoionization and electron cascade caused by the intense x-ray pulse. For general x-ray imaging techniques, the minimization of the effects of radiation damage is of major concern to ensure reliable reconstruction of molecular structure. Here in this paper, we show that radiation damage free diffraction can be achieved with atomic spatial resolution by using x-ray parametric down-conversion and ghostmore » diffraction with entangled photons of x-ray and optical frequencies. We show that the formation of the diffraction patterns satisfies a condition analogous to the Bragg equation, with a resolution that can be as fine as the crystal lattice length scale of several Ångstrom. Since the samples are illuminated by low energy optical photons, they can be free of radiation damage.« less

Radiation damage free ghost diffraction with atomic resolution

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

Li, Zheng; Medvedev, Nikita; Chapman, Henry N.

The x-ray free electron lasers can enable diffractive structural determination of protein nanocrystals and single molecules that are too small and radiation-sensitive for conventional x-ray diffraction. However the electronic form factor may be modified during the ultrashort x-ray pulse due to photoionization and electron cascade caused by the intense x-ray pulse. For general x-ray imaging techniques, the minimization of the effects of radiation damage is of major concern to ensure reliable reconstruction of molecular structure. Here in this paper, we show that radiation damage free diffraction can be achieved with atomic spatial resolution by using x-ray parametric down-conversion and ghostmore » diffraction with entangled photons of x-ray and optical frequencies. We show that the formation of the diffraction patterns satisfies a condition analogous to the Bragg equation, with a resolution that can be as fine as the crystal lattice length scale of several Ångstrom. Since the samples are illuminated by low energy optical photons, they can be free of radiation damage.« less

Synchrotron Radiation X-ray Diffraction Techniques Applied to Insect Flight Muscle.

PubMed

Iwamoto, Hiroyuki

2018-06-13

X-ray fiber diffraction is a powerful tool used for investigating the molecular structure of muscle and its dynamics during contraction. This technique has been successfully applied not only to skeletal and cardiac muscles of vertebrates but also to insect flight muscle. Generally, insect flight muscle has a highly ordered structure and is often capable of high-frequency oscillations. The X-ray diffraction studies on muscle have been accelerated by the advent of 3rd-generation synchrotron radiation facilities, which can generate brilliant and highly oriented X-ray beams. This review focuses on some of the novel experiments done on insect flight muscle by using synchrotron radiation X-rays. These include diffraction recordings from single myofibrils within a flight muscle fiber by using X-ray microbeams and high-speed diffraction recordings from the flight muscle during the wing-beat of live insects. These experiments have provided information about the molecular structure and dynamic function of flight muscle in unprecedented detail. Future directions of X-ray diffraction studies on muscle are also discussed.

Interfacial binding of divalent cations to calixarene-based Langmuir monolayers

DOE PAGES

Tulli, Ludovico G.; Wang, Wenjie; Lindemann, William R.; ...

2015-02-20

The interactions of Langmuir monolayers produced through the self-assembly of an amphiphilic p-carboxycalix[4]arene with a series of divalent, fourth-period transition metals, at the air-water interface, were investigated. Changes in the interfacial behavior of 1 in response to the presence of CuCl 2, CoCl 2, MnCl 2, and NiCl 2 were studied by means of Langmuir compression isotherms and Brewster angle microscopy (BAM). The measurements revealed that the self-assembly properties of 1 are significantly affected by Cu 2+ ions. The interactions of 1-based monolayers with Co 2+ and Cu 2+ ions were further investigated by means of synchrotron radiation-based X-ray reflectivitymore » (XRR), X-ray near-total-reflection fluorescence (XNTRF), and grazing incidence X-ray diffraction (GIXD). XNTRF and XRR analyses revealed that the monolayer of 1 binds more strongly to Cu 2+ than Co 2+ ions. In the presence of relatively high concentrations of Cu 2+ ions in the subphase (1.4 × 10 -3 M), XNTRF exhibited anomalous depth profile behavior and GIXD measurements showed considerably strong diffuse scattering. Furthermore, both measurements suggest the formation of Cu 2+ clusters contiguous to the monolayer of 1.« less

Phase Changes of Monosulfoaluminate in NaCl Aqueous Solution

DOE PAGES

Yoon, Seyoon; Ha, Juyoung; Chae, Sejung Rosie; ...

2016-05-21

Monosulfoaluminate (Ca 4Al 2(SO 4)(OH) 12∙6H 2O) plays an important role in anion binding in Portland cement by exchanging its original interlayer ions (SO 4 2- and OH -) with chloride ions. In this study, scanning transmission X-ray microscope (STXM), X-ray absorption near edge structure (XANES) spectroscopy, and X-ray diffraction (XRD) were used to investigate the phase change of monosulfoaluminate due to its interaction with chloride ions. Pure monosulfoaluminate was synthesized and its powder samples were suspended in 0, 0.1, 1, 3, and 5 M NaCl solutions for seven days. At low chloride concentrations, a partial dissolution of monosulfoaluminate formedmore » ettringite, while, with increasing chloride content, the dissolution process was suppressed. As the NaCl concentration increased, the dominant mechanism of the phase change became ion exchange, resulting in direct phase transformation from monosulfoaluminate to Kuzel’s salt or Friedel’s salt. The phase assemblages of the NaCl-reacted samples were explored using thermodynamic calculations and least-square linear combination (LC) fitting of measured XANES spectra. A comprehensive description of the phase change and its dominant mechanism are discussed.« less

One-Step Fast-Synthesized Foamlike Amorphous Co(OH)2 Flexible Film on Ti Foil by Plasma-Assisted Electrolytic Deposition as a Binder-Free Anode of a High-Capacity Lithium-Ion Battery.

PubMed

Li, Tao; Nie, Xueyuan

2018-05-23

This research prepared an amorphous Co(OH) 2 flexible film on Ti foil using plasma-assisted electrolytic deposition within 3.5 min. Amorphous Co(OH) 2 structure was determined by X-ray diffraction and X-ray photoelectron spectroscopy. Its areal capacity testing as the binder and adhesive-free anode of a lithium-ion battery shows that the cycling capacity can reach 2000 μAh/cm 2 and remain at 930 μAh/cm 2 after 50 charge-discharge cycles, which benefits from the emerging Co(OH) 2 active material and amorphous foamlike structure. The research introduced a new method to synthesize amorphous Co(OH) 2 as the anode in a fast-manufactured low-cost lithium-ion battery.

Combined analysis of 1,3-benzodioxoles by crystalline sponge X-ray crystallography and laser desorption ionization mass spectrometry.

PubMed

Hayashi, Yukako; Ohara, Kazuaki; Taki, Rika; Saeki, Tomomi; Yamaguchi, Kentaro

2018-03-12

The crystalline sponge (CS) method, which employs single-crystal X-ray diffraction to determine the structure of an analyte present as a liquid or an oil and having a low melting point, was used in combination with laser desorption ionization mass spectrometry (LDI-MS). 1,3-Benzodioxole derivatives were encapsulated in CS and their structures were determined by combining X-ray crystallography and MS. After the X-ray analysis, the CS was subjected to imaging mass spectrometry (IMS) with an LDI spiral-time-of-flight mass spectrometer (TOF-MS). The ion detection area matched the microscopic image of the encapsulated CS. In addition, the accumulated 1D mass spectra showed that fragmentation of the guest molecule (hereafter, guest) can be easily visualized without any interference from the fragment ions of CS except for two strong ion peaks derived from the tridentate ligand TPT (2,4,6-tris(4-pyridyl)-1,3,5-triazine) of the CS and its fragment. X-ray analysis clearly showed the presence of the guest as well as the π-π, CH-halogen, and CH-O interactions between the guest and the CS framework. However, some guests remained randomly diffused in the nanopores of CS. In addition, the detection limit was less than sub-pmol order based on the weight and density of CS determined by X-ray analysis. Spectroscopic data, such as UV-vis and NMR, also supported the encapsulation of the guest through the interaction between the guest and CS components. The results denote that the CS-LDI-MS method, which combines CS, X-ray analysis and LDI-MS, is effective for structure determination.

Argon-ion-induced formation of nanoporous GaSb layer: Microstructure, infrared luminescence, and vibrational properties

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

Datta, D. P.; Som, T., E-mail: tsom@iopb.res.in; Kanjilal, A.

2014-07-21

Room temperature implantation of 60 keV Ar{sup +}-ions in GaSb to the fluences of 7 × 10{sup 16} to 3 × 10{sup 18} ions cm{sup −2} is carried out at two incidence angles, viz 0° and 60°, leading to formation of a nanoporous layer. As the ion fluence increases, patches grow on the porous layer under normal ion implantation, whereas the porous layer gradually becomes embedded under a rough top surface for oblique incidence of ions. Grazing incidence x-ray diffraction and cross-sectional transmission electron microscopy studies reveal the existence of nanocrystallites embedded in the ion-beam amorphized GaSb matrix up to the highest fluence used inmore » our experiment. Oxidation of the nanoporous layers becomes obvious from x-ray photoelectron spectroscopy and Raman mapping. The correlation of ion-beam induced structural modification with photoluminescence signals in the infrared region has further been studied, showing defect induced emission of additional peaks near the band edge of GaSb.« less

Rapid prototyping of Fresnel zone plates via direct Ga(+) ion beam lithography for high-resolution X-ray imaging.

PubMed

Keskinbora, Kahraman; Grévent, Corinne; Eigenthaler, Ulrike; Weigand, Markus; Schütz, Gisela

2013-11-26

A significant challenge to the wide utilization of X-ray microscopy lies in the difficulty in fabricating adequate high-resolution optics. To date, electron beam lithography has been the dominant technique for the fabrication of diffractive focusing optics called Fresnel zone plates (FZP), even though this preparation method is usually very complicated and is composed of many fabrication steps. In this work, we demonstrate an alternative method that allows the direct, simple, and fast fabrication of FZPs using focused Ga(+) beam lithography practically, in a single step. This method enabled us to prepare a high-resolution FZP in less than 13 min. The performance of the FZP was evaluated in a scanning transmission soft X-ray microscope where nanostructures as small as sub-29 nm in width were clearly resolved, with an ultimate cutoff resolution of 24.25 nm, demonstrating the highest first-order resolution for any FZP fabricated by the ion beam lithography technique. This rapid and simple fabrication scheme illustrates the capabilities and the potential of direct ion beam lithography (IBL) and is expected to increase the accessibility of high-resolution optics to a wider community of researchers working on soft X-ray and extreme ultraviolet microscopy using synchrotron radiation and advanced laboratory sources.

Combining experiment and optical simulation in coherent X-ray nanobeam characterization of Si/SiGe semiconductor heterostructures

DOE PAGES

Tilka, J. A.; Park, J.; Ahn, Y.; ...

2016-07-06

Here, the highly coherent and tightly focused x-ray beams produced by hard x-ray light sources enable the nanoscale characterization of the structure of electronic materials but are accompanied by significant challenges in the interpretation of diffraction and scattering patterns. X-ray nanobeams exhibit optical coherence combined with a large angular divergence introduced by the x-ray focusing optics. The scattering of nanofocused x-ray beams from intricate semiconductor heterostructures produces a complex distribution of scattered intensity. We report here an extension of coherent xray optical simulations of convergent x-ray beam diffraction patterns to arbitrary x-ray incident angles to allow the nanobeam diffraction patternsmore » of complex heterostructures to be simulated faithfully. These methods are used to extract the misorientation of lattice planes and the strain of individual layers from synchrotron x-ray nanobeam diffraction patterns of Si/SiGe heterostructures relevant to applications in quantum electronic devices. The systematic interpretation of nanobeam diffraction patterns from semiconductor heterostructures presents a new opportunity in characterizing and ultimately designing electronic materials.« less

Ion beam sputtering of fluoropolymers. [etching polymer films and target surfaces

NASA Technical Reports Server (NTRS)

Sovey, J. S.

1978-01-01

Ion beam sputter processing rates as well as pertinent characteristics of etched targets and films are described. An argon ion beam source was used to sputter etch and deposit the fluoropolymers PTFE, FEP, and CTFE. Ion beam energy, current density, and target temperature were varied to examine effects on etch and deposition rates. The ion etched fluoropolymers yield cone or spire-like surface structures which vary depending upon the type of polymer, ion beam power density, etch time, and target temperature. Sputter target and film characteristics documented by spectral transmittance measurements, X-ray diffraction, ESCA, and SEM photomicrographs are included.

Electrodeposition of WO3 nanoparticles into surface mounted metal-organic framework HKUST-1 thin films

NASA Astrophysics Data System (ADS)

Yoo, Hyeonseok; Welle, Alexander; Guo, Wei; Choi, Jinsub; Redel, Engelbert

2017-03-01

We describe a novel procedure to fabricate WO3@surface-mounted metal-organic framework (SURMOF) hybrid materials by electrodeposition of WO3 nanoparticles into HKUST-1, also termed Cu3(BTC)2 SURMOFs. These materials have been characterized using x-ray diffraction, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, x-ray photoelectron spectroscopy as well as linear sweep voltammetry. The WO3 semiconductor/SURMOF heterostructures were further tested as hybrid electrodes in their performance for hydrogen evolution reaction from water.

Electrodeposition of WO3 nanoparticles into surface mounted metal-organic framework HKUST-1 thin films.

PubMed

Yoo, Hyeonseok; Welle, Alexander; Guo, Wei; Choi, Jinsub; Redel, Engelbert

2017-03-17

We describe a novel procedure to fabricate WO 3 @surface-mounted metal-organic framework (SURMOF) hybrid materials by electrodeposition of WO 3 nanoparticles into HKUST-1, also termed Cu 3 (BTC) 2 SURMOFs. These materials have been characterized using x-ray diffraction, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, x-ray photoelectron spectroscopy as well as linear sweep voltammetry. The WO 3 semiconductor/SURMOF heterostructures were further tested as hybrid electrodes in their performance for hydrogen evolution reaction from water.

Structure of semiconducting versus fast-ion conducting glasses in the Ag–Ge–Se system

PubMed Central

2018-01-01

The transition from a semiconductor to a fast-ion conductor with increasing silver content along the Agx(Ge0.25Se0.75)(100−x) tie line (0≤x≤25) was investigated on multiple length scales by employing a combination of electric force microscopy, X-ray diffraction, and neutron diffraction. The microscopy results show separation into silver-rich and silver-poor phases, where the Ag-rich phase percolates at the onset of fast-ion conductivity. The method of neutron diffraction with Ag isotope substitution was applied to the x=5 and x=25 compositions, and the results indicate an evolution in structure of the Ag-rich phase with change of composition. The Ag–Se nearest-neighbours are distributed about a distance of 2.64(1) Å, and the Ag–Se coordination number increases from 2.6(3) at x=5 to 3.3(2) at x=25. For x=25, the measured Ag–Ag partial pair-distribution function gives 1.9(2) Ag–Ag nearest-neighbours at a distance of 3.02(2) Å. The results show breakage of Se–Se homopolar bonds as silver is added to the Ge0.25Se0.75 base glass, and the limit of glass-formation at x≃28 coincides with an elimination of these bonds. A model is proposed for tracking the breakage of Se–Se homopolar bonds as silver is added to the base glass. PMID:29410843

A water stable europium coordination polymer as fluorescent sensor for detecting Fe3+, CrO42-, and Cr2O72- ions

NASA Astrophysics Data System (ADS)

Chen, Chen; Zhang, Xiaolei; Gao, Peng; Hu, Ming

2018-02-01

A europium coordination polymer constructed by the 4‧-(4-carboxyphenyl)- 2,2‧:6‧,2″-terpyridine ligand (HL), namely, [EuL(CH3COO)Cl]n (1), has been prepared by the solvothermal method. Compound 1 was structurally characterized by the elemental analysis, FT-IR, powder X-ray diffractions (PXRD), thermogravimetric (TG) analysis, and single-crystal X-ray diffraction. Complex 1 displays a novel linear chain structure, which further extends to the 3D supramolecular structure via π···π and hydrogen bonds interactions. The luminescent properties of 1 were investigated in detail, which exhibit the fluorescent sensing for detecting Fe3+, CrO42-, and Cr2O72- ions in aqueous solution, respectively. In addition, 1 shows high sensitive and selective sensing for CrO42- and Cr2O72- anions with the great quenching efficiency. Furthermore, the luminescent sensing mechanisms of differentiating analytes are explored in detail. It is worth noting that there exists the weak interaction between Fe3+ ions and carboxylate oxygen atoms of CH3COO- groups through XPS characterization, resulting in the high quenching effect of 1.

In situ defect annealing of swift heavy ion irradiated CeO 2 and ThO 2 using synchrotron X-ray diffraction and a hydrothermal diamond anvil cell

DOE PAGES

Palomares, Raul I.; Tracy, Cameron L.; Zhang, Fuxiang; ...

2015-04-16

Hydrothermal diamond anvil cells (HDACs) provide facile means for coupling synchrotron Xray techniques with pressure up to 10 GPa and temperature up to 1300 K. This manuscript reports on an application of the HDAC as an ambient-pressure sample environment for performing in situ defect annealing and thermal expansion studies of swift heavy ion irradiated CeO 2 and ThO 2 using synchrotron X-ray diffraction. The advantages of the in situ HDAC technique over conventional annealing methods include: rapid temperature ramping and quench times, high-resolution measurement capability, simultaneous annealing of multiple samples, and prolonged temperature- and apparatus stability at high temperatures. Isochronalmore » annealing between 300 K and 1100 K revealed 2-stage and 1-stage defect recovery processes for irradiated CeO 2 and ThO 2, respectively; indicating that the morphology of the defects produced by swift heavy ion irradiation of these two materials differs significantly. These results suggest that electronic configuration plays a major role in both the radiation-induced defect production and high temperature defect recovery mechanisms of CeO 2 and ThO 2.« less

Charge–discharge properties of tin dioxide for sodium-ion battery

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

Park, Jinsoo; Park, Jin-Woo; Han, Jeong-Hui

Highlights: • The electrochemical reaction of SnO2 as an anode for Na-ion batteries was studied. • The SnO2 electrode delivered the initial discharge capacity of 747 mAh/g. • Alarge irreversible capacity (597 mAh/g)was observedin the first cycle. • The in-plain crack in the electrode caused the incompletereduction of SnO{sub 2}. - Abstract: Tin dioxide was investigated as an anode material for sodium-ion batteries. The Na/SnO{sub 2} cell delivered a first discharge capacity of 747 mAh/g, but the first charge capacity was 150 mAh/g. The irreversible capacity in the first cycle was examined through characterization by X-ray diffraction and scanning electron microscopy.more » X-ray diffraction analysis revealed that the SnO{sub 2} active material was not reduced fully to metallic Sn. Furrows and wrinkles were formed on the electrode surface owing to the volumetric expansion upon first discharge, which led to a deterioration of the electrode structure and a loss of electrical contact between the active materials. The analysis is summarized in the schematic drawing.« less

Structure of high alumina content Al2O3-SiO2 composition glasses.

PubMed

Weber, Richard; Sen, Sabyasachi; Youngman, Randall E; Hart, Robert T; Benmore, Chris J

2008-12-25

The structure of binary aluminosilicate glasses containing 60-67 mol % Al2O3 were investigated using high-resolution 27Al NMR and X-ray and neutron diffraction. The glasses were made by aerodynamic levitation of molten oxides. The 67% alumina composition required a cooling rate of approximately 1600 degrees C s(1-) to form glass from submillimeter sized samples. NMR results show that the glasses contain aluminum in 4-, 5-, and 6-fold coordination in the approximate ratio 4:5:1. The average Al coordination increases from 4.57 to 4.73 as the fraction of octahedral Al increases with alumina content. The diffraction results on the 67% composition are consistent with a disordered Al framework with Al ions in a range of coordination environments that are substantially different from those found in the equilibrium crystalline phases. Analysis of the neutron and X-ray structure factors yields an average bond angle of 125 +/- 4 degrees between an Al ion and the adjoining cation via a bridging oxygen. We propose that the structure of the glass is a "transition state" between the alumina-rich liquid and the equilibrium mullite phase that are dominated by 4- and 6-coordinated aluminum ions, respectively.

Fabrication and testing of a newly designed slit system for depth-resolved X-ray diffraction measurements

DOE PAGES

Sinsheimer, John; Bouet, Nathalie; Ghose, Sanjit; ...

2016-10-06

A new system of slits called `spiderweb slits' have been developed for depth-resolved powder or polycrystalline X-ray diffraction measurements. The slits act on diffracted X-rays to select a particular gauge volume of sample, while absorbing diffracted X-rays from outside of this volume. Although the slit geometry is to some extent similar to that of previously developed conical slits or spiral slits, this new design has advantages over the previous ones in use for complex heterogeneous materials and in situ and operando diffraction measurements. For example, the slits can measure a majority of any diffraction cone for any polycrystalline material, overmore » a continuous range of diffraction angles, and work for X-ray energies of tens to hundreds of kiloelectronvolts. In addition, the design is generated and optimized using ray-tracing simulations, and fabricated through laser micromachining. The first prototype was successfully tested at the X17A beamline at the National Synchrotron Light Source, and shows similar performance to simulations, demonstrating gauge volume selection for standard powders, for all diffraction peaks over angles of 2–10°. A similar, but improved, design will be implemented at the X-ray Powder Diffraction beamline at the National Synchrotron Light Source II.« less

Controllable deposition of platinum nanoparticles on single-wall carbon nanohorns as catalyst for direct methanol fuel cells.

PubMed

Niu, Ben; Xu, Wei; Guo, Zhengduo; Zhou, Nengzhi; Liu, Yang; Shi, Zujin; Lian, Yongfu

2012-09-01

Uniform and well dispersed platinum nanoparticles were successfully deposited on single-walled carbon nanohorns with the assistance of 4,4-dipydine and ion liquids, respectively. In particular, the size of platinum nanoparticles could be controlled in a very narrow range (2.2 to 2.5 nm) when ion liquids were applied. The crystalline nature of these platinum nanoparticles was confirmed by high resolution transmission electron microscopy observation and X-ray power diffraction analysis, and two species of platinum Pt(0) and Pt(II) were detected by X-ray photoelectron spectroscopy. Electrochemical studies revealed that thus obtained nanocomposites had much better electrocatalytic activity for the methanol oxidation than those prepared with carbon nanotubes as supporter.

Nanocrystalline hydroxyapatite doped with selenium oxyanions: a new material for potential biomedical applications.

PubMed

Kolmas, Joanna; Oledzka, Ewa; Sobczak, Marcin; Nałęcz-Jawecki, Grzegorz

2014-06-01

Selenium-substituted hydroxyapatites containing selenate SeO4(2-) or selenite SeO3(2-) ions were synthesized using a wet precipitation method. The selenium content was determined by atomic absorbance spectrometry. The raw, unsintered powders were also characterized using powder X-ray diffraction, middle-range FT-IR spectroscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopic microanalysis. The synthesized apatites were found to be pure and nanocrystalline with a crystal size similar to that in bone mineral. The incorporation of selenium oxyanions into the crystal lattice was confirmed. The toxicity of hydroxyapatites containing selenite or selenate ions was evaluated with a protozoan assay and bacterial luminescence test. Copyright © 2014 Elsevier B.V. All rights reserved.

Following the electroreduction of uranium dioxide to uranium in LiCl-KCl eutectic in situ using synchrotron radiation

NASA Astrophysics Data System (ADS)

Brown, L. D.; Abdulaziz, R.; Jervis, R.; Bharath, V. J.; Atwood, R. C.; Reinhard, C.; Connor, L. D.; Simons, S. J. R.; Inman, D.; Brett, D. J. L.; Shearing, P. R.

2015-09-01

The electrochemical reduction of uranium dioxide to metallic uranium has been investigated in lithium chloride-potassium chloride eutectic molten salt. Laboratory based electrochemical studies have been coupled with in situ energy dispersive X-ray diffraction, for the first time, to deduce the reduction pathway. No intermediate phases were identified using the X-ray diffraction before, during or after electroreduction to form α-uranium. This suggests that the electrochemical reduction occurs via a single, 4-electron-step, process. The rate of formation of α-uranium is seen to decrease during electrolysis and could be a result of a build-up of oxygen anions in the molten salt. Slow transport of O2- ions away from the UO2 working electrode could impede the electrochemical reduction.

Dynamical scattering in coherent hard x-ray nanobeam Bragg diffraction

NASA Astrophysics Data System (ADS)

Pateras, A.; Park, J.; Ahn, Y.; Tilka, J. A.; Holt, M. V.; Kim, H.; Mawst, L. J.; Evans, P. G.

2018-06-01

Unique intensity features arising from dynamical diffraction arise in coherent x-ray nanobeam diffraction patterns of crystals having thicknesses larger than the x-ray extinction depth or exhibiting combinations of nanoscale and mesoscale features. We demonstrate that dynamical scattering effects can be accurately predicted using an optical model combined with the Darwin theory of dynamical x-ray diffraction. The model includes the highly divergent coherent x-ray nanobeams produced by Fresnel zone plate focusing optics and accounts for primary extinction, multiple scattering, and absorption. The simulation accurately reproduces the dynamical scattering features of experimental diffraction patterns acquired from a GaAs/AlGaAs epitaxial heterostructure on a GaAs (001) substrate.

Coherent x-ray diffraction imaging with nanofocused illumination.

PubMed

Schroer, C G; Boye, P; Feldkamp, J M; Patommel, J; Schropp, A; Schwab, A; Stephan, S; Burghammer, M; Schöder, S; Riekel, C

2008-08-29

Coherent x-ray diffraction imaging is an x-ray microscopy technique with the potential of reaching spatial resolutions well beyond the diffraction limits of x-ray microscopes based on optics. However, the available coherent dose at modern x-ray sources is limited, setting practical bounds on the spatial resolution of the technique. By focusing the available coherent flux onto the sample, the spatial resolution can be improved for radiation-hard specimens. A small gold particle (size <100 nm) was illuminated with a hard x-ray nanobeam (E=15.25 keV, beam dimensions approximately 100 x 100 nm2) and is reconstructed from its coherent diffraction pattern. A resolution of about 5 nm is achieved in 600 s exposure time.

Cross-sectional transmission electron microscopic study of irradiation induced nano-crystallization of nickel in a W/Ni multilayer.

PubMed

Bagchi, Sharmistha; Lalla, N P

2008-06-11

The present study reports the cross-sectional transmission electron microscopic investigations of swift heavy ion-irradiation induced nano-size recrystallization of Ni in a nearly immiscible W/Ni multilayer structure. Multilayer structures (MLS) of [W(25 Å)/Ni(25 Å)](10BL) were grown on Si-(100) substrate by the ion-beam sputtering technique. The as-synthesized MLS were subjected to 120 MeV-Au(9+) ion-irradiation to a fluence of ∼5 × 10(13) ions cm(-2). Wide-angle x-ray diffraction studies of pristine as well as irradiated W/Ni multilayers show deterioration of the superlattice structure, whereas x-ray reflectivity (XRR) measurement reveals a nearly unaffected microstructure after irradiation. Analysis of the XRR data using 'Parratt's formalism' does show a significant increase of W/Ni interface roughness. Cross-sectional transmission electron microscopy (TEM) studies carried out in diffraction and imaging modes (including bright-field and dark-field imaging), show that at high irradiation dose the intralayer microstructure of Ni becomes nano-crystalline (1-2 nm). During these irradiation induced changes of the intralayer microstructure, the interlayer definition of the W and Ni layers still remains intact. The observed nano-recrystallization of Ni has been attributed to competition between low miscibility of the W/Ni interface and the ion-beam induced mixing kinetics.

Local Structure and Surface Properties of CoxZn1-xO Thin Films for Ozone Gas Sensing.

PubMed

Catto, Ariadne C; Silva, Luís F da; Bernardi, Maria Inês B; Bernardini, Sandrine; Aguir, Khalifa; Longo, Elson; Mastelaro, Valmor R

2016-10-05

A detailed study of the structural, surface, and gas-sensing properties of nanostructured Co x Zn 1-x O films is presented. X-ray diffraction (XRD) analysis revealed a decrease in the crystallization degree with increasing Co content. The X-ray absorption near-edge structure (XANES) and X-ray photoelectron spectroscopies (XPS) revealed that the Co 2+ ions preferentially occupied the Zn 2+ sites and that the oxygen vacancy concentration increased as the amount of cobalt increased. Electrical measurements showed that the Co dopants not only enhanced the sensor response at low ozone levels (ca. 42 ppb) but also led to a decrease in the operating temperature and improved selectivity. The enhancement in the gas-sensing properties was attributed to the presence of oxygen vacancies, which facilitated ozone adsorption.

DynAMITe: a prototype large area CMOS APS for breast cancer diagnosis using x-ray diffraction measurements

NASA Astrophysics Data System (ADS)

Konstantinidis, A.; Anaxagoras, T.; Esposito, M.; Allinson, N.; Speller, R.

2012-03-01

X-ray diffraction studies are used to identify specific materials. Several laboratory-based x-ray diffraction studies were made for breast cancer diagnosis. Ideally a large area, low noise, linear and wide dynamic range digital x-ray detector is required to perform x-ray diffraction measurements. Recently, digital detectors based on Complementary Metal-Oxide- Semiconductor (CMOS) Active Pixel Sensor (APS) technology have been used in x-ray diffraction studies. Two APS detectors, namely Vanilla and Large Area Sensor (LAS), were developed by the Multidimensional Integrated Intelligent Imaging (MI-3) consortium to cover a range of scientific applications including x-ray diffraction. The MI-3 Plus consortium developed a novel large area APS, named as Dynamically Adjustable Medical Imaging Technology (DynAMITe), to combine the key characteristics of Vanilla and LAS with a number of extra features. The active area (12.8 × 13.1 cm2) of DynaMITe offers the ability of angle dispersive x-ray diffraction (ADXRD). The current study demonstrates the feasibility of using DynaMITe for breast cancer diagnosis by identifying six breast-equivalent plastics. Further work will be done to optimize the system in order to perform ADXRD for identification of suspicious areas of breast tissue following a conventional mammogram taken with the same sensor.

Resolution enhancement in coherent x-ray diffraction imaging by overcoming instrumental noise.

PubMed

Kim, Chan; Kim, Yoonhee; Song, Changyong; Kim, Sang Soo; Kim, Sunam; Kang, Hyon Chol; Hwu, Yeukuang; Tsuei, Ku-Ding; Liang, Keng San; Noh, Do Young

2014-11-17

We report that reference objects, strong scatterers neighboring weak phase objects, enhance the phase retrieval and spatial resolution in coherent x-ray diffraction imaging (CDI). A CDI experiment with Au nano-particles exhibited that the reference objects amplified the signal-to-noise ratio in the diffraction intensity at large diffraction angles, which significantly enhanced the image resolution. The interference between the diffracted x-ray from reference objects and a specimen also improved the retrieval of the phase of the diffraction signal. The enhancement was applied to image NiO nano-particles and a mitochondrion and confirmed in a simulation with a bacteria phantom. We expect that the proposed method will be of great help in imaging weakly scattering soft matters using coherent x-ray sources including x-ray free electron lasers.

H2 Production Under Visible Light Irradiation from Aqueous Methanol Solution on CaTiO3:Cu Prepared by Spray Pyrolysis

NASA Astrophysics Data System (ADS)

Lim, Sung Nam; Song, Shin Ae; Jeong, Yong-Cheol; Kang, Hyun Woo; Park, Seung Bin; Kim, Ki Young

2017-10-01

Perovskite-type photocatalysts of CaCu x Ti1- x O3 (0 ≤ x ≤ 0.02) powder were prepared by spray pyrolysis of aqueous solution or aqueous solution with polymeric additive. The effects of the amount of copper ions doped in the photocatalyst and the precursor type on the photocatalytic activity under visible-light irradiation were investigated. The crystal structure, oxidation state, and light adsorption properties of the prepared photocatalysts were analyzed using x-ray diffraction, x-ray photoelectron spectroscopy, and diffuse reflectance spectroscopy, respectively. The doping of copper ions in CaTiO3 allowed visible-light absorption owing to a narrowing of the band gap energy of the host material through the formation of a new donor level for copper ions. Among the doped samples prepared from the aqueous precursor, CaTiO3 doped with 1 mol.% copper ions had the highest hydrogen evolution rate (140.7 μmol g-1 h-1). Notably, the hydrogen evolution rate of the photocatalyst doped with 1 mol.% copper ions prepared from the aqueous precursor with polymeric additive (295.0 μmol g-1 h-1) was two times greater than that prepared from the aqueous precursor, due to the morphology effect.

Structural, dielectric and impedance spectroscopic studies of Ni0.5Zn0.5-xLixFe2O4 nanocrystalline ferrites

NASA Astrophysics Data System (ADS)

Venkatesh, Davuluri; Ramesh, K. V.

2017-09-01

Nanocrystalline lithium substituted Ni-Zn ferrites with composition Ni0.5Zn0.5-xLixFe2O4 (x = 0.00-0.25 in steps of 0.05) were synthesized by the citrate gel auto-combustion method and were sintered at 1000∘C for 4 h in air atmosphere. The structural, dielectric, impedance spectroscopic and magnetic properties were studied by using X-ray diffraction, impedance analyzer and vibrating sample magnetometer respectively. The X-ray diffraction patterns confirm that all samples exhibit a single phase cubic spinel structure. Suitable cation distribution for all compositions has been proposed by using the X-ray diffraction line intensity calculations and the theoretical lattice parameter for each composition was observed in close agreement with the experimental ones and thereby supporting the proposed distribution. An increase in the saturation magnetization was observed up to x = 0.10 level of Li+ substitution and thereafter magnetization reduced for higher concentrations to the highest level of Li+ substitution. The dielectric constant and the DC resistivity of Ni-Zn-Li ferrites were noticed to decrease with increase in the Li+ ion concentration. The impedance spectroscopic studies by using the Cole-Cole plots were studied in order to obtain the relaxation time, grain resistance and grain capacitance. AC conductivity initially remained almost independent of frequency for lower frequencies and thereafter for higher frequencies the AC conductivity increased with increase of Lithium concentration.

Focused ion beam direct micromachining of DOEs

NASA Astrophysics Data System (ADS)

Khan Malek, Chantal; Hartley, Frank T.; Neogi, Jayant

2000-09-01

We discuss here the capability of direct manufacture of various high- resolution diffractive optics, in particular regarding micromachining of DOEs in 3D. Preliminary demonstrations were made in 2-D using an automated FIB system operated at 30 KeV with a Gallium liquid metal ion source and equipped with a gas injection system (GIS). Gratings with a 20 nm line width and zone plates with 32 nm outer ring were milled in a reactive atmosphere (iodine) directly through 3.5 (mu) m and 800 nm of gold respectively. Plans for combining FIB and X-ray lithography to make diffractive optical elements (DOEs) for JPL are also mentioned.

Fabrication and testing of a newly designed slit system for depth-resolved X-ray diffraction measurements

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

Sinsheimer, John; Bouet, Nathalie; Ghose, Sanjit

2016-10-06

A new system of slits called `spiderweb slits' have been developed for depth-resolved powder or polycrystalline X-ray diffraction measurements. The slits act on diffracted X-rays to select a particular gauge volume of sample, while absorbing diffracted X-rays from outside of this volume. Although the slit geometry is to some extent similar to that of previously developed conical slits or spiral slits, this new design has advantages over the previous ones in use for complex heterogeneous materials andin situandoperandodiffraction measurements. For example, the slits can measure a majority of any diffraction cone for any polycrystalline material, over a continuous range ofmore » diffraction angles, and work for X-ray energies of tens to hundreds of kiloelectronvolts. The design is generated and optimized using ray-tracing simulations, and fabricated through laser micromachining. The first prototype was successfully tested at the X17A beamline at the National Synchrotron Light Source, and shows similar performance to simulations, demonstrating gauge volume selection for standard powders, for all diffraction peaks over angles of 2–10°. A similar, but improved, design will be implemented at the X-ray Powder Diffraction beamline at the National Synchrotron Light Source II.« less

One-Step Hydrothermal Synthesis of Zeolite X Powder from Natural Low-Grade Diatomite.

PubMed

Yao, Guangyuan; Lei, Jingjing; Zhang, Xiaoyu; Sun, Zhiming; Zheng, Shuilin

2018-05-28

Zeolite X powder was synthesized using natural low-grade diatomite as the main source of Si but only as a partial source of Al via a simple and green hydrothermal method. The microstructure and surface properties of the obtained samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), wavelength dispersive X-ray fluorescence (XRF), calcium ion exchange capacity (CEC), thermogravimetric-differential thermal (TG-DTA) analysis, and N₂ adsorption-desorption technique. The influence of various synthesis factors, including aging time and temperature, crystallization time and temperature, Na₂O/SiO₂ and H₂O/Na₂O ratio on the CEC of zeolite, were systematically investigated. The as-synthesized zeolite X with binary meso-microporous structure possessed remarkable thermal stability, high calcium ion exchange capacity of 248 mg/g and large surface area of 453 m²/g. In addition, the calcium ion exchange capacity of zeolite X was found to be mainly determined by the crystallization degree. In conclusion, the synthesized zeolite X using diatomite as a cost-effective raw material in this study has great potential for industrial application such as catalyst support and adsorbent.

Local terahertz field enhancement for time-resolved x-ray diffraction

DOE PAGES

Kozina, M.; Pancaldi, M.; Bernhard, C.; ...

2017-02-20

We report local field strength enhancement of single-cycle terahertz (THz) pulses in an ultrafast time-resolved x-ray diffraction experiment. We show that patterning the sample with gold microstructures increases the THz field without changing the THz pulse shape or drastically affecting the quality of the x-ray diffraction pattern. Lastly, we find a five-fold increase in THz-induced x-ray diffraction intensity change in the presence of microstructures on a SrTiO 3 thin-film sample.

Local terahertz field enhancement for time-resolved x-ray diffraction

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

Kozina, M.; Pancaldi, M.; Bernhard, C.

We report local field strength enhancement of single-cycle terahertz (THz) pulses in an ultrafast time-resolved x-ray diffraction experiment. We show that patterning the sample with gold microstructures increases the THz field without changing the THz pulse shape or drastically affecting the quality of the x-ray diffraction pattern. Lastly, we find a five-fold increase in THz-induced x-ray diffraction intensity change in the presence of microstructures on a SrTiO 3 thin-film sample.

Thermal x-ray diffraction and near-field phase contrast imaging

NASA Astrophysics Data System (ADS)

Li, Zheng; Classen, Anton; Peng, Tao; Medvedev, Nikita; Wang, Fenglin; Chapman, Henry N.; Shih, Yanhua

2017-10-01

Using higher-order coherence of thermal light sources, the resolution power of standard x-ray imaging techniques can be enhanced. In this work, we applied the higher-order measurement to far-field x-ray diffraction and near-field phase contrast imaging (PCI), in order to achieve superresolution in x-ray diffraction and obtain enhanced intensity contrast in PCI. The cost of implementing such schemes is minimal compared to the methods that achieve similar effects by using entangled x-ray photon pairs.

Thermal x-ray diffraction and near-field phase contrast imaging

DOE PAGES

Li, Zheng; Classen, Anton; Peng, Tao; ...

2017-12-27

Using higher-order coherence of thermal light sources, the resolution power of standard x-ray imaging techniques can be enhanced. Here in this work, we applied the higher-order measurement to far-field x-ray diffraction and near-field phase contrast imaging (PCI), in order to achieve superresolution in x-ray diffraction and obtain enhanced intensity contrast in PCI. The cost of implementing such schemes is minimal compared to the methods that achieve similar effects by using entangled x-ray photon pairs.

Synthesis of PbTe thermoelectric film by high energy heavy ion beam mixing

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

Gupta, Srashti; Neeleshwar, S.; Agarwal, D. C.

2011-12-12

The Te/Pb bilayer samples were prepared by sequential thermal evaporation of Pb and Te on glass substrate. These bilayer samples were irradiated by 100 MeV Ag{sup 9+} at different fluences (3x10{sup 12}, 1x10{sup 13}, and 3x10{sup 13} ions/cm{sup 2}) to synthesis PbTe by ion beam mixing. The samples were characterized by RBS to study composition and X-ray diffraction (XRD) for phase identification before and after irradiation. Thickness of Pb and Te were 75 nm and 105 nm respectively in pristine film as deduced from RBS analysis. The RBS of irradiated sample indicates the mixing between Pb and Te layers. XRDmore » revealed phases of PbTe in sample irradiated at 3x10{sup 13} ions/cm{sup 2}. This phase formation may be due to inter diffusion across the interface induced by swift heavy ion irradiation.« less

An image focusing means by using an opaque object to diffract x-rays

DOEpatents

Sommargren, Gary E.; Weaver, H. Joseph

1991-01-01

The invention provides a method and apparatus for focusing and imaging x-rays. An opaque sphere is used as a diffractive imaging element to diffract x-rays from an object so that the divergent x-ray wavefronts are transformed into convergent wavefronts and are brought to focus to form an image of the object with a large depth of field.

Clocking Femtosecond Collisional Dynamics via Resonant X-Ray Spectroscopy

NASA Astrophysics Data System (ADS)

van den Berg, Q. Y.; Fernandez-Tello, E. V.; Burian, T.; Chalupský, J.; Chung, H.-K.; Ciricosta, O.; Dakovski, G. L.; Hájková, V.; Hollebon, P.; Juha, L.; Krzywinski, J.; Lee, R. W.; Minitti, M. P.; Preston, T. R.; de la Varga, A. G.; Vozda, V.; Zastrau, U.; Wark, J. S.; Velarde, P.; Vinko, S. M.

2018-02-01

Electron-ion collisional dynamics is of fundamental importance in determining plasma transport properties, nonequilibrium plasma evolution, and electron damage in diffraction imaging applications using bright x-ray free-electron lasers (FELs). Here we describe the first experimental measurements of ultrafast electron impact collisional ionization dynamics using resonant core-hole spectroscopy in a solid-density magnesium plasma, created and diagnosed with the Linac Coherent Light Source x-ray FEL. By resonantly pumping the 1 s →2 p transition in highly charged ions within an optically thin plasma, we have measured how off-resonance charge states are populated via collisional processes on femtosecond time scales. We present a collisional cross section model that matches our results and demonstrates how the cross sections are enhanced by dense-plasma effects including continuum lowering. Nonlocal thermodynamic equilibrium collisional radiative simulations show excellent agreement with the experimental results and provide new insight on collisional ionization and three-body-recombination processes in the dense-plasma regime.

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

Ghosh, Koushik; Balog, Eva Rose M.; Sista, Prakash

We report a method for creating hybrid organic-inorganic “nanoflowers” using calcium or copper ions as the inorganic component and a recombinantly expressed elastin-like polypeptide (ELP) as the organic component. Polypeptides provide binding sites for the dynamic coordination with metal ions, and then such noncovalent complexes become nucleation sites for primary crystals of metal phosphates. We have shown that the interaction between the stimuli-responsive ELP and Ca{sup 2+} or Cu{sup 2+}, in the presence of phosphate, leads to the growth of micrometer-sized particles featuring nanoscale patterns shaped like flower petals. The morphology of these flower-like composite structures is dependent upon themore » temperature of growth and has been characterized by scanning electron microscopy. The composition of nanoflowers has also been analyzed by energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. The temperature-dependent morphologies of these hybrid nanostructures, which arise from the controllable phase transition of ELPs, hold potential for morphological control of biomaterials in emerging applications such as tissue engineering and biocatalysis.« less

Clocking Femtosecond Collisional Dynamics via Resonant X-Ray Spectroscopy

DOE PAGES

van den Berg, Q. Y.; Fernandez-Tello, E. V.; Burian, T.; ...

2018-02-01

Electron-ion collisional dynamics is of fundamental importance in determining plasma transport properties, nonequilibrium plasma evolution, and electron damage in diffraction imaging applications using bright x-ray free-electron lasers (FELs). Here in this paper, we describe the first experimental measurements of ultrafast electron impact collisional ionization dynamics using resonant core-hole spectroscopy in a solid-density magnesium plasma, created and diagnosed with the Linac Coherent Light Source x-ray FEL. By resonantly pumping the 1s → 2p transition in highly charged ions within an optically thin plasma, we have measured how off-resonance charge states are populated via collisional processes on femtosecond time scales. We presentmore » a collisional cross section model that matches our results and demonstrates how the cross sections are enhanced by dense-plasma effects including continuum lowering. Nonlocal thermodynamic equilibrium collisional radiative simulations show excellent agreement with the experimental results and provide new insight on collisional ionization and three-body-recombination processes in the dense-plasma regime.« less

Preferential uptake of ammonium ions by zinc ferrocyanide

NASA Technical Reports Server (NTRS)

Braterman, P. S.; Arrhenius, G.; Hui, S.; Paplawsky, W.; Miller, S. L. (Principal Investigator)

1995-01-01

The concentration of ammonia from dilute aqueous solution could have facilitated many prebiotic reactions. This may be especially true if this concentration involves incorporation into an organized medium. We have shown that (unlike iron(III) ferrocyanide) zinc ferrocyanide,Zn2Fe(CN)6 xH2O, preferentially takes up ammonium ions from 0.01 M NH4Cl to give the known material Zn3(NH4)2[Fe(CN)6]2 xH2O, even in the presence of 0.01 M KCl. KCl alone gave Zn3K2[Fe(CN)6]2 xH2O. Products were characterized by elemental (CHN) analysis and powder X-ray diffraction (XRD). We attribute the remarkable specificity for the ammonium ion to the open framework of the product, which offers enough space for hydrogen-bonded ammonium ions, and infer that other inorganic materials with internal spaces rich in water may show a similar preference.

Modification of Optical, Structural and Dielectric Properties of MeV Ions Irradiated PS/Cu Nanocomposites.

PubMed

Gavade, Chaitali; Singh, N L; Khanna, P K; Shah, Sunil

2015-12-01

In order to study structural, thermal, optical and dielectric behaviors of composites, the films of Cu/polystyrene nanocomposites were synthesized at different concentrations of Cu-nanoparticles. These polymer nanocomposites were irradiated with carbon (85 MeV) and silicon (120 MeV) ions at different fluences. The samples were characterized using different techniques viz: X-ray diffraction, UV-visible spectroscopy, differential scanning calorimetry, and impedance gain phase analyzer. A noticeable increase in the intensity of X-ray diffraction peaks was observed after irradiation with 120 MeV Si-ions, which may be attributed to radiation-induced cross-linking in polymer. Optical properties like band gap was estimated for pure polymer and nanocomposite films from their optical absorption spectra in the wavelength region 200-800 nm. It was found that the band gap value shifted to lower energy (from 4.38 eV to 3.40 eV) on doping with silver nanoparticles and also upon irradiation. Differential scanning calorimetry analysis revealed an increase in the glass transition temperature upon irradiation, which may be attributed to cross linking of polymer chain due to ion beam irradiation which is also corroborated with XRD analysis. Dependence of dielectric properties on frequency, ions and filler concentration was studied. The results revealed the enhancement in dielectric properties after doping nanoparticles and also upon irradiation. It was observed that the effect of Si-beam is more effectual than the C-beam because of large electronic energy loss of heavy ion.

EPR and optical investigations of LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor

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

Singh, Vijay, E-mail: vijayjiin2006@yahoo.com; Sivaramaiah, G.; Rao, J.L.

2014-12-15

Graphical abstract: The EPR spectrum of as-prepared LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor at 110 K. - Highlights: • Using the combustion synthesis, LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor has been prepared in a few minutes. • Optical investigation indicates that Cr{sup 3+} ions are present in octahedral symmetry. • The EPR signals indicate that exchange coupled Cr{sup 3+}–Cr{sup 3+} ion pairs in weakly distorted sites. - Abstract: The LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor has been prepared by a low-temperature combustion synthesis method. As-prepared combustion synthesized powder was characterized using powder X-ray diffraction (XRD), diffuse reflectance (DRS), electron paramagnetic resonance (EPR) andmore » photoluminescence (PL) studies. The X-ray diffraction pattern reveals crystalline hexagonal phases. The UV–vis diffuse reflectance spectrum exhibits three broad bands characteristic of Cr{sup 3+} ions in octahedral symmetry. The EPR spectrum exhibits several resonance signals. The signals with the effective g values at g = 4.84, 3.64 and 2.26 have been attributed to the isolated Cr{sup 3+} ions. The signal with the effective g value at g = 1.94 has been attributed to exchange coupled Cr{sup 3+}–Cr{sup 3+} ion pairs. The PL studies exhibit several bands characteristic of Cr{sup 3+} ions in octahedral symmetry.« less

Soft X-Ray Diffraction Microscopy of a Frozen Hydrated Yeast Cell

DOE PAGES

Huang, Xiaojing; Nelson, Johanna; Kirz, Janos; ...

2009-11-01

We report the first image of an intact, frozen hydrated eukaryotic cell using x-ray diffraction microscopy, or coherent x-ray diffraction imaging. By plunge freezing the specimen in liquid ethane and maintaining it below -170 °C, artifacts due to dehydration, ice crystallization, and radiation damage are greatly reduced. In this example, coherent diffraction data using 520 eV x rays were recorded and reconstructed to reveal a budding yeast cell at a resolution better than 25 nm. This demonstration represents an important step towards high resolution imaging of cells in their natural, hydrated state, without limitations imposed by x-ray optics.

Coating and functionalization of high density ion track structures by atomic layer deposition

NASA Astrophysics Data System (ADS)

Mättö, Laura; Szilágyi, Imre M.; Laitinen, Mikko; Ritala, Mikko; Leskelä, Markku; Sajavaara, Timo

2016-10-01

In this study flexible TiO2 coated porous Kapton membranes are presented having electron multiplication properties. 800 nm crossing pores were fabricated into 50 μm thick Kapton membranes using ion track technology and chemical etching. Consecutively, 50 nm TiO2 films were deposited into the pores of the Kapton membranes by atomic layer deposition using Ti(iOPr)4 and water as precursors at 250 °C. The TiO2 films and coated membranes were studied by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray reflectometry (XRR). Au metal electrode fabrication onto both sides of the coated foils was achieved by electron beam evaporation. The electron multipliers were obtained by joining two coated membranes separated by a conductive spacer. The results show that electron multiplication can be achieved using ALD-coated flexible ion track polymer foils.

Freeze-drying synthesis of three-dimensional porous LiFePO4 modified with well-dispersed nitrogen-doped carbon nanotubes for high-performance lithium-ion batteries

NASA Astrophysics Data System (ADS)

Tu, Xiaofeng; Zhou, Yingke; Song, Yijie

2017-04-01

The three-dimensional porous LiFePO4 modified with uniformly dispersed nitrogen-doped carbon nanotubes has been successfully prepared by a freeze-drying method. The morphology and structure of the porous composites are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performances are evaluated using the constant current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The nitrogen-doped carbon nanotubes are uniformly dispersed inside the porous LiFePO4 to construct a superior three-dimensional conductive network, which remarkably increases the electronic conductivity and accelerates the diffusion of lithium ion. The porous composite displays high specific capacity, good rate capability and excellent cycling stability, rendering it a promising positive electrode material for high-performance lithium-ion batteries.

Self-Protection Mechanism of Hexagonal WO3-Based DeNOx Catalysts against Alkali Poisoning.

PubMed

Zheng, Li; Zhou, Meijuan; Huang, Zhiwei; Chen, Yaxin; Gao, Jiayi; Ma, Zhen; Chen, Jianmin; Tang, Xingfu

2016-11-01

A good catalyst for efficiently controlling NO x emissions often demands strong resistance against alkali poisoning. Although the traditional ion-exchange model, based on acid-base reactions of alkalis with Brønsted acid sites, has been established over the past two decades, it is difficult to be used as a guideline to develop such an alkali-resistant catalyst. Here we establish a self-protection mechanism of deNO x catalysts against alkali poisoning by systematically studying the intrinsic nature of alkali resistance of V 2 O 5 /HWO (HWO = hexagonal WO 3 ) that shows excellent resistance to alkali poisoning in selective catalytic reduction of NO x with NH 3 (SCR). Synchrotron X-ray diffraction and absorption spectroscopies demonstrate that V 2 O 5 /HWO has spatially separated catalytically active sites (CASs) and alkali-trapping sites (ATSs). During the SCR process, ATSs spontaneously trap alkali ions such as K + , even if alkali ions initially block CASs, thus releasing CASs to realize the self-protection against alkali poisoning. X-ray photoelectron spectra coupled with theoretical calculations indicate that the electronic interaction between the alkali ions and ATSs with an energy saving is the driving force of the self-protection. This work provides a strategy to design alkali-resistant deNO x catalysts.

Application of focused-beam flat-sample method to synchrotron powder X-ray diffraction with anomalous scattering effect

NASA Astrophysics Data System (ADS)

Tanaka, M.; Katsuya, Y.; Matsushita, Y.

2013-03-01

The focused-beam flat-sample method (FFM), which is a method for high-resolution and rapid synchrotron X-ray powder diffraction measurements by combination of beam focusing optics, a flat shape sample and an area detector, was applied for diffraction experiments with anomalous scattering effect. The advantages of FFM for anomalous diffraction were absorption correction without approximation, rapid data collection by an area detector and good signal-to-noise ratio data by focusing optics. In the X-ray diffraction experiments of CoFe2O4 and Fe3O4 (By FFM) using X-rays near the Fe K absorption edge, the anomalous scattering effect between Fe/Co or Fe2+/Fe3+ can be clearly detected, due to the change of diffraction intensity. The change of observed diffraction intensity as the incident X-ray energy was consistent with the calculation. The FFM is expected to be a method for anomalous powder diffraction.

Microstructural and opto-electrical properties of chromium nitride films implanted with vanadium ions

NASA Astrophysics Data System (ADS)

Novaković, M.; Traverse, A.; Popović, M.; Lieb, K. P.; Zhang, K.; Bibić, N.

2012-07-01

We report on modifications of 280-nm thin polycrystalline CrN layers caused by vanadium ion implantation. The CrN layers were deposited at 150°C by d.c. reactive sputtering on Si(100) wafers and then implanted at room temperature with 80-keV V+ ions to fluences of 1×1017 and 2×1017 ions/cm2. Rutherford backscattering spectroscopy, cross-sectional transmission electron microscopy, and X-ray diffraction were used to characterize changes in the structural properties of the films. Their optical and electrical properties were analyzed by infrared spectroscopy in reflection mode and electrical resistivity measurements. CrN was found to keep its cubic structure under the conditions of vanadium ion implantation used here. The initially partially non-metallic CrN layer displays metallic character under implantation, which may be related to the possible formation of Cr1-x V x N.

Synthesis of carbon-encapsulated metal nanoparticles from wood char

Treesearch

Yicheng Du; Chuji Wang; Hossein Toghiani; Zhiyong Cai; Xiaojian Liu; Jilei Zhang; Qiangu Yan

2010-01-01

Carbon-encapsulated metal nanoparticles were synthesized by thermal treatment of wood char, with or without transition metal ions pre-impregnated, at 900ºC to 1,100ºC. Nanoparticles with concentric multilayer shells were observed. The nanoparticles were analyzed by scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction...

Structural and Spectral Characterization of Co2+- and Ni2+-DOPED CdO Powder Prepared From Solution at Room Temperature

NASA Astrophysics Data System (ADS)

Reddy, C. V.; Rao, L. V. Krishna; Satish, D. V.; Shim, J.; Ravikumar, R. V. S. S. N.

2015-11-01

The mild and simple solution method was used for the synthesis of Co2+- and Ni2+-doped CdO powders at room temperature. The prepared powders were characterized using powder X-ray diffraction, scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), optical absorption, and Fourier transform infrared spectroscopy (FTIR). From the powder X-ray diffraction patterns, it has been observed that the prepared Co2+ and Ni2+ ion-doped CdO powders belong to the cubic phase, and the evaluated average crystalline sizes of the powders are 20 and 14 nm, respectively. The SEM images and the EDS spectra show that the prepared powders are distributed over different sizes in the grain boundaries. Optical absorption studies allow determination of site symmetry of the metal ion with its ligands. The crystal field (Dq) and inter-electronic repulsion (B and C) parameters have been evaluated from the optical absorption spectra. The FTIR spectra show the characteristic fundamental vibrations of the metal oxide and CdO.

Preparation and evaluation of thin-film sodium tungsten bronzes

NASA Technical Reports Server (NTRS)

Kautz, H. E.; Fielder, W. L.; Singer, J.; Fordyce, J. S.

1974-01-01

Thin films of sodium tungsten bronze (NaxWO3) were investigated as reversible sodium ion electrodes for solid electrolytes. The films were made by electron beam evaporation of the three phases, W metal, Na2WO4, and WO3, followed by sintering. The substrates were sodium beta alumina disks and glass slides. X-ray diffraction analyses of the films showed that sintering in dry nitrogen with prior exposure to air lead to mixed phases. Sintering in vacuum with no air exposure produced tetragonal I bronze with a nominal composition of Na0.31WO3, single phase within the limits of X-ray diffraction detectability. The films were uniform and adherent on sodium beta alumina substrates. The ac and dc conductivities of the beta alumina were measured with the sodium tungsten bronze films as electrodes. These experiments indicated that the tetragonal I bronze electrodes were not completely reversible. This may have resulted from sodium ion blocking within the bronze film or at the bronze beta alumina interface. Methods for attempting to make more completely reversible electrodes are suggested.

Strain relaxation of CdTe on Ge studied by medium energy ion scattering

NASA Astrophysics Data System (ADS)

Pillet, J. C.; Pierre, F.; Jalabert, D.

2016-10-01

We have used the medium energy ion scattering (MEIS) technique to assess the strain relaxation in molecular-beam epitaxial (MBE) grown CdTe (2 1 1)/Ge (2 1 1) system. A previous X-ray diffraction study, on 10 samples of the same heterostructure having thicknesses ranging from 25 nm to 10 μm has allowed the measurement of the strain relaxation on a large scale. However, the X-ray diffraction measurements cannot achieve a stress measurement in close proximity to the CdTe/Ge interface at the nanometer scale. Due to the huge lattice misfit between the CdTe and Ge, a high degree of disorder is expected at the interface. The MEIS in channeling mode is a good alternative in order to profile defects with a high depth resolution. For a 21 nm thick CdTe layer, we observed, at the interface, a high density of Cd and/or Te atoms moved from their expected crystallographic positions followed by a rapid recombination of defects. Strain relaxation mechanisms in the vicinity of the interface are discussed

Selective sensing of two novel coordination polymers based on tris(4-carboxylphenyl)phosphine oxide for organic molecules and Fe3+ and Hg2+ ions

NASA Astrophysics Data System (ADS)

Huo, Liangqin; Zhang, Jie; Gao, Lingling; Wang, Xiaoqing; Fan, Liming; Fang, Kegong; Hu, Tuoping

2017-12-01

Two novel coordination polymers, formulated as {[Zn(HTPO)(bib)]·4H2O}n (1), {[Cu3(TPO)2 (bib)3]·2DMF·0.5EtOH·0.5H2O}n (2) (H3TPO = tris(4-carboxylphenyl)phosphine oxide; bib = 1,4-bis(1H-imidazol-4-yl) benzene), have been synthesized under solvothermal method and characterized by single-crystal X-ray diffraction, elemental analysis (EA), IR spectra, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD). Structural analysis reveals that complex 1 is a 2D 4-connected sheet with an intriguing 2D + 2D→2D network. Complex 2 displays a 3D 3,4-connected net with the point symbol of {103}2{106}3. Furthermore, the photoluminescence properties of 1 and 2 were investigated in the solid state and various solvent emulsions, the results show that 1 and 2 have better fluorescent recognition for organic molecules, Fe3+ and Hg2+ ions.

The Barium Site in a Potassium Channel by X-Ray Crystallography

PubMed Central

Jiang, Youxing; MacKinnon, Roderick

2000-01-01

X-ray diffraction data were collected from frozen crystals (100°K) of the KcsA K+ channel equilibrated with solutions containing barium chloride. Difference electron density maps (Fbarium − Fnative, 5.0 Å resolution) show that Ba2+ resides at a single location within the selectivity filter. The Ba2+ blocking site corresponds to the internal aspect (adjacent to the central cavity) of the “inner ion” position where an alkali metal cation is found in the absence of the blocking Ba2+ ion. The location of Ba2+ with respect to Rb+ ions in the pore is in good agreement with the findings on the functional interaction of Ba2+ with K+ (and Rb+) in Ca2+-activated K+ channels (Neyton, J., and C. Miller. 1988. J. Gen. Physiol. 92:549–567). Taken together, these structural and functional data imply that at physiological ion concentrations a third ion may interact with two ions in the selectivity filter, perhaps by entering from one side and displacing an ion on the opposite side. PMID:10694255

Advanced techniques for characterization of ion beam modified materials

DOE PAGES

Zhang, Yanwen; Debelle, Aurélien; Boulle, Alexandre; ...

2014-10-30

Understanding the mechanisms of damage formation in materials irradiated with energetic ions is essential for the field of ion-beam materials modification and engineering. Utilizing incident ions, electrons, photons, and positrons, various analysis techniques, including Rutherford backscattering spectrometry (RBS), electron RBS, Raman spectroscopy, high-resolution X-ray diffraction, small-angle X-ray scattering, and positron annihilation spectroscopy, are routinely used or gaining increasing attention in characterizing ion beam modified materials. The distinctive information, recent developments, and some perspectives in these techniques are reviewed in this paper. Applications of these techniques are discussed to demonstrate their unique ability for studying ion-solid interactions and the corresponding radiationmore » effects in modified depths ranging from a few nm to a few tens of μm, and to provide information on electronic and atomic structure of the materials, defect configuration and concentration, as well as phase stability, amorphization and recrystallization processes. Finally, such knowledge contributes to our fundamental understanding over a wide range of extreme conditions essential for enhancing material performance and also for design and synthesis of new materials to address a broad variety of future energy applications.« less

Investigating the Intercalation Chemistry of Alkali Ions in Fluoride Perovskites

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

Yi, Tanghong; Chen, Wei; Cheng, Lei

Reversible intercalation reactions provide the basis for modern battery electrodes. In spite of the decades of exploration of electrode materials, the potential for materials in the nonoxide chemical space with regards to intercalation chemistry is vast and rather untested. Transition metal fluorides stand out as an obvious target. To this end, we report herein a new family of iron fluoride-based perovskite cathode materials A xK 1–xFeF 3 (A = Li, Na). By starting with KFeF 3, approximately 75% of K+ ions were subsequently replaced by Li + and Na + through electrochemical means. X-ray diffraction and Fe X-ray absorption spectroscopymore » confirmed the existence of intercalation of alkali metal ions in the perovskite structure, which is associated with the Fe 2+/3+ redox couple. A computational study by density functional theory showed agreement with the structural and electrochemical data obtained experimentally, which suggested the possibility of fluoride-based materials as potential intercalation electrodes. Our study increases our understanding of the intercalation chemistry of ternary fluorides, which could inform efforts toward the exploration of new electrode materials.« less

Investigating the Intercalation Chemistry of Alkali Ions in Fluoride Perovskites

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

Yi, Tanghong; Chen, Wei; Cheng, Lei

Reversible intercalation reactions provide the basis for modern battery electrodes. Despite decades of exploration of electrode materials, the potential for materials in the nonoxide chemical space with regards to intercalation chemistry is vast and rather untested. Transition metal fluorides stand out as an obvious target. To this end, we report herein a new family of iron fluoride-based perovskite cathode materials A xK 1–xFeF 3 (A = Li, Na). By starting with KFeF 3, approximately 75% of K + ions were subsequently replaced by Li + and Na + through electrochemical means. X-ray diffraction and Fe X-ray absorption spectroscopy confirmed themore » existence of intercalation of alkali metal ions in the perovskite structure, which is associated with the Fe 2+/3+ redox couple. A computational study by density functional theory showed agreement with the structural and electrochemical data obtained experimentally, which suggested the possibility of fluoride-based materials as potential intercalation electrodes. This study increases our understanding of the intercalation chemistry of ternary fluorides, which could inform efforts toward the exploration of new electrode materials.« less

Investigating the Intercalation Chemistry of Alkali Ions in Fluoride Perovskites

DOE PAGES

Yi, Tanghong; Chen, Wei; Cheng, Lei; ...

2017-01-20

Reversible intercalation reactions provide the basis for modern battery electrodes. In spite of the decades of exploration of electrode materials, the potential for materials in the nonoxide chemical space with regards to intercalation chemistry is vast and rather untested. Transition metal fluorides stand out as an obvious target. To this end, we report herein a new family of iron fluoride-based perovskite cathode materials A xK 1–xFeF 3 (A = Li, Na). By starting with KFeF 3, approximately 75% of K+ ions were subsequently replaced by Li + and Na + through electrochemical means. X-ray diffraction and Fe X-ray absorption spectroscopymore » confirmed the existence of intercalation of alkali metal ions in the perovskite structure, which is associated with the Fe 2+/3+ redox couple. A computational study by density functional theory showed agreement with the structural and electrochemical data obtained experimentally, which suggested the possibility of fluoride-based materials as potential intercalation electrodes. Our study increases our understanding of the intercalation chemistry of ternary fluorides, which could inform efforts toward the exploration of new electrode materials.« less

2.7 MeV Ar11+ ion irradiation induced structural evolution in Lu2(Ti2-xLux)O7-x/2 pyrochlores

NASA Astrophysics Data System (ADS)

Yang, D. Y.; Liu, C. G.; Zhang, K. Q.; Xia, Y.; Chen, L. J.; Liu, H.; Li, Y. H.

2015-11-01

This paper aims to study the radiation effects of nonstoichiometric pyrochlore series Lu2(Ti2-xLux)O7-x/2 (x = 0-0.667). Polycrystalline Lu2(Ti2-xLux)O7-x/2 samples were irradiated with 2.7 MeV Ar11+ ions up to a fluence of 8 × 1014 ions/cm2. The irradiated samples were characterized using grazing incidence X-ray diffraction technique. The results reveal that Lu2(Ti2-xLux)O7-x/2 samples undergo significant amorphization and lattice swelling upon irradiation. Specifically, the amorphization process is predominantly driven by ballistic nuclear energy deposition of Ar11+ ions at this energy regime, which can be well described by a direct-impact/defect-stimulated model. Both the amorphization fraction and the relative variation of lattice parameter decrease with increasing x, showing a strong dependence on the chemical composition. The results are then discussed in the framework of the structural disorder and recovery ability from damage, applying an atomic layer model.

Statistical Nature of Atomic Disorder in Irradiated Crystals.

PubMed

Boulle, A; Debelle, A

2016-06-17

Atomic disorder in irradiated materials is investigated by means of x-ray diffraction, using cubic SiC single crystals as a model material. It is shown that, besides the determination of depth-resolved strain and damage profiles, x-ray diffraction can be efficiently used to determine the probability density function (PDF) of the atomic displacements within the crystal. This task is achieved by analyzing the diffraction-order dependence of the damage profiles. We thereby demonstrate that atomic displacements undergo Lévy flights, with a displacement PDF exhibiting heavy tails [with a tail index in the γ=0.73-0.37 range, i.e., far from the commonly assumed Gaussian case (γ=2)]. It is further demonstrated that these heavy tails are crucial to account for the amorphization kinetics in SiC. From the retrieved displacement PDFs we introduce a dimensionless parameter f_{D}^{XRD} to quantify the disordering. f_{D}^{XRD} is found to be consistent with both independent measurements using ion channeling and with molecular dynamics calculations.

Statistical Nature of Atomic Disorder in Irradiated Crystals

NASA Astrophysics Data System (ADS)

Boulle, A.; Debelle, A.

2016-06-01

Atomic disorder in irradiated materials is investigated by means of x-ray diffraction, using cubic SiC single crystals as a model material. It is shown that, besides the determination of depth-resolved strain and damage profiles, x-ray diffraction can be efficiently used to determine the probability density function (PDF) of the atomic displacements within the crystal. This task is achieved by analyzing the diffraction-order dependence of the damage profiles. We thereby demonstrate that atomic displacements undergo Lévy flights, with a displacement PDF exhibiting heavy tails [with a tail index in the γ =0.73 - 0.37 range, i.e., far from the commonly assumed Gaussian case (γ =2 )]. It is further demonstrated that these heavy tails are crucial to account for the amorphization kinetics in SiC. From the retrieved displacement PDFs we introduce a dimensionless parameter fDXRD to quantify the disordering. fDXRD is found to be consistent with both independent measurements using ion channeling and with molecular dynamics calculations.

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

Moorhouse, Saul J.; Wu, Yue; O’Hare, Dermot, E-mail: dermot.ohare@chem.ox.ac.uk

A newly developed in situ monochromatic high-energy X-ray diffraction setup was used to investigate the synthesis of MOFs using cation-impregnated polymer resin beads as a ion source. The Co–NDC–DMF (NDC=2,6-naphthalenedicarboxylate; DMF=dimethylformamide) system was investigated, a system which is known to produce at least three distinct frameworks. It was found that the resin-assisted synthesis results in the preferential formation of a topology previously impossible to synthesise in bulk, while the comparable nitrate-salt synthesis appeared to form an alternative phases. It was also found that the resin-assisted synthesis is highly diffusion-controlled. - Graphical abstract: In situ monochromatic high-energy X-ray diffraction study ofmore » a MOF synthesis. - Highlights: • Resin-assisted solvothermal MOF synthesis was studied using in situ diffraction. • Full kinetics of reaction can be obtained from in situ data. • Kinetics show that this resin-assisted synthesis is diffusion controlled. • Resin-assisted synthesis enables the production of an alternative bulk phase.« less

The migration mechanism of transition metal ions in LiNi 0.5 Mn 1.5O 4

DOE PAGES

Xu, Gui-Liang; Qin, Yan; Ren, Yang; ...

2015-05-12

The migration of transition metal ions in the oxygen framework was recently proposed to be responsible for the continuous loss of average working potential of high energy density layered–layered composite cathodes for lithium-ion batteries. The potential migration pathway in a model material, LiNi 0.5 Mn 1.5O 4 spinel, was investigated using in situ high-energy X-ray diffraction and in situ neutron diffraction during the solid state synthesis process. It was found that the migration of transition metal ions among octahedral sites is possible by using tetrahedral vacancies as intermediate sites. It was also suggested that the number of electrons in 3dmore » orbitals has a significant impact on their mobility in the hosting oxygen framework.« less

Silicon etch with chromium ions generated by a filtered or non-filtered cathodic arc discharge

PubMed Central

Scopece, Daniele; Döbeli, Max; Passerone, Daniele; Maeder, Xavier; Neels, Antonia; Widrig, Beno; Dommann, Alex; Müller, Ulrich; Ramm, Jürgen

2016-01-01

Abstract The pre-treatment of substrate surfaces prior to deposition is important for the adhesion of physical vapour deposition coatings. This work investigates Si surfaces after the bombardment by energetic Cr ions which are created in cathodic arc discharges. The effect of the pre-treatment is analysed by X-ray diffraction, Rutherford backscattering spectroscopy, scanning electron microscopy and in-depth X-ray photoemission spectroscopy and compared for Cr vapour produced from a filtered and non-filtered cathodic arc discharge. Cr coverage as a function of ion energy was also predicted by TRIDYN Monte Carlo calculations. Discrepancies between measured and simulated values in the transition regime between layer growth and surface removal can be explained by the chemical reactions between Cr ions and the Si substrate or between the substrate surface and the residual gases. Simulations help to find optimum and more stable parameters for specific film and substrate combinations faster than trial-and-error procedure. PMID:27877854

Interface mediated enhanced mixing of multilayered Ni-Bi thin films by swift heavy ion irradiation

NASA Astrophysics Data System (ADS)

Siva, V.; Chettah, A.; Ojha, S.; Tripathi, A.; Kanjilal, D.; Sahoo, Pratap K.

2017-10-01

We report the effect of ion beam mixing of Ni/Bi multilayers using 100 MeV Au ions as a function of irradiation fluences. X-ray diffraction study reveals the higher magnitude of NiBi3 and NiBi phases compared to elemental Ni and Bi after ion irradiation. We observe an evolution of grainy structures to a molten-like surface with increasing ion fluences. These features were also reflected in the Rutherford Backscattering spectrometry spectra, in terms of the enhanced mixing with increasing ion fluences. The experimental findings were understood on the basis of inelastic thermal spike model calculations.

Attainable high capacity in Li-excess Li-Ni-Ru-O rock-salt cathode for lithium ion battery

NASA Astrophysics Data System (ADS)

Wang, Xingbo; Huang, Weifeng; Tao, Shi; Xie, Hui; Wu, Chuanqiang; Yu, Zhen; Su, Xiaozhi; Qi, Jiaxin; Rehman, Zia ur; Song, Li; Zhang, Guobin; Chu, Wangsheng; Wei, Shiqiang

2017-08-01

Peroxide structure O2n- has proven to appear after electrochemical process in many lithium-excess precious metal oxides, representing extra reversible capacity. We hereby report construction of a Li-excess rock-salt oxide Li1+xNi1/2-3x/2Ru1/2+x/2O2 electrode, with cost effective and eco-friendly 3d transition metal Ni partially substituting precious 4d transition metal Ru. It can be seen that O2n- is formed in pristine Li1.23Ni0.155Ru0.615O2, and stably exists in subsequent cycles, enabling discharge capacities to 295.3 and 198 mAh g-1 at the 1st/50th cycle, respectively. Combing ex-situ X-ray absorption near edge spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, high resolution transmission electron microscopy and electrochemical characterization, we demonstrate that the excellent electrochemical performance comes from both percolation network with disordered structure and cation/anion redox couples occurring in charge-discharge process. Li-excess and substitution of common element have been demonstrated to be a breakthrough for designing novel high performance commercial cathodes in rechargeable lithium ion battery field.

Surface modification of tantalum pentoxide coatings deposited by magnetron sputtering and correlation with cell adhesion and proliferation in in vitro tests

NASA Astrophysics Data System (ADS)

Zykova, A.; Safonov, V.; Goltsev, A.; Dubrava, T.; Rossokha, I.; Donkov, N.; Yakovin, S.; Kolesnikov, D.; Goncharov, I.; Georgieva, V.

2016-03-01

The effect was analyzed of surface treatment by argon ions on the surface properties of tantalum pentoxide coatings deposited by reactive magnetron sputtering. The structural parameters of the as-deposited coatings were investigated by means of transmission electron microscopy, atomic force microscopy and scanning electron microscopy. X-ray diffraction profiles and X-ray photoelectron spectra were also acquired. The total surface free energy (SFE), the polar, dispersion parts and fractional polarities, were estimated by the Owens-Wendt-Rabel-Kaeble method. The adhesive and proliferative potentials of bone marrow cells were evaluated for both Ta2O5 coatings and Ta2O5 coatings deposited by simultaneous bombardment by argon ions in in vitro tests.

A porous Cd(II) metal-organic framework with high adsorption selectivity for CO2 over CH4

NASA Astrophysics Data System (ADS)

Zhu, Chunlan

2017-05-01

Metal-organic frameworks (MOFs) have attracted a lot of attention in recent decades. We applied a semi-rigid four-carboxylic acid linker to assemble with Cd(II) ions to generate a novel microporous Cd(II) MOF material. Single crystal X-ray diffraction study reveals the different two dimension (2D) layers can be further packed together with an AB fashion by hydrogen bonds (O4sbnd H4⋯O7 = 1.863 Å) to construct a three dimension (3D) supermolecular architecture. The resulting sample can be synthesized under solvothermal reactions successfully, which exhibits high selectivity adsorption of CO2 over CH4 at room temperature. In addition, the obtained sample was characterized by thermal gravimetric analyses (TGA), Fourier-transform infrared spectra (FT-IR), elemental analysis (CHN) and powder X-ray diffraction (PXRD).

Response of Gd 2 Ti 2 O 7 and La 2 Ti 2 O 7 to swift-heavy ion irradiation and annealing

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

Park, Sulgiye; Lang, Maik; Tracy, Cameron L.

2015-07-01

Swift heavy ion (2 GeV 181Ta) irradiation-induced amorphization and temperature-induced recrystallization of cubic pyrochlore Gd2Ti2O7 (Fd3¯m) are compared with the response of a compositionally-similar material with a monoclinic-layered perovskite-type structure, La2Ti2O7 (P21). The averaged electronic energy loss, dE/dx, was 37 keV/nm and 35 keV/nm in Gd2Ti2O7 and La2Ti2O7, respectively. Systematic analysis of the structural modifications was completed using transmission electron microscopy, synchrotron X-ray diffraction, Raman spectroscopy, and small-angle X-ray scattering. Increasing ion-induced amorphization with increasing ion fluence was evident in the X-ray diffraction patterns of both compositions by a reduction in the intensity of the diffraction maxima concurrent with themore » growth in intensity of a broad diffuse scattering halo. Transmission electron microscopy analysis showed complete amorphization within ion tracks (diameter: ~10 nm) for the perovskite-type material; whereas a concentric, core–shell morphology was evident in the ion tracks of the pyrochlore, with an outer shell of disordered yet still crystalline material with the fluorite structure surrounding an amorphous track core (diameter: ~9 nm). The radiation response of both titanate oxides with the same stoichiometry can be understood in terms of differences in their structures and compositions. While the radiation damage susceptibility of pyrochlore A2B2O7 materials decreases as a function of the cation radius ratio rA/rB, the current study correlates this behavior with the stability field of monoclinic structures, where rLa/rTi > rGd/rTi. Isochronal annealing experiments of the irradiated materials showed complete recrystallization of La2Ti2O7 at 775 °C and of Gd2Ti2O7 at 850 °C. The annealing behavior is discussed in terms of enhanced damage recovery in La2Ti2O7, compared to the pyrochlore compounds Gd2Ti2O7. The difference in the recrystallization behavior may be related to structural constraints, i.e., reconstructing a low symmetry versus a high symmetry phase.« less

Dynamical effects in Bragg coherent x-ray diffraction imaging of finite crystals

NASA Astrophysics Data System (ADS)

Shabalin, A. G.; Yefanov, O. M.; Nosik, V. L.; Bushuev, V. A.; Vartanyants, I. A.

2017-08-01

We present simulations of Bragg coherent x-ray diffractive imaging (CXDI) data from finite crystals in the frame of the dynamical theory of x-ray diffraction. The developed approach is based on a numerical solution of modified Takagi-Taupin equations and can be applied for modeling of a broad range of x-ray diffraction experiments with finite three-dimensional crystals of arbitrary shape also in the presence of strain. We performed simulations for nanocrystals of a cubic and hemispherical shape of different sizes and provided a detailed analysis of artifacts in the Bragg CXDI reconstructions introduced by the dynamical diffraction. Based on our theoretical analysis we developed an analytical procedure to treat effects of refraction and absorption in the reconstruction. Our results elucidate limitations for the kinematical approach in the Bragg CXDI and suggest a natural criterion to distinguish between kinematical and dynamical cases in coherent x-ray diffraction on a finite crystal.

Hydrothermal growth of CuO nanoleaf structures, and their mercuric ion detection application.

PubMed

Ibupoto, Z H; Khun, K; Willander, M

2014-09-01

Mercury is the hazardous heavy metal ion for the environment and the human being therefore its determination is very important and herein we describe the development of mercury ion sensor on the CuO nanoleaf like nanostructures using cetyltrimethylammonium bromide (CTAB) surfactant as template for the growth by hydrothermal growth method. Scanning electron microscopy and X-ray diffraction study has shown high density and good crystal quality of the fabricated CuO nanostructures respectively. The presented mercury ion sensor has detected the wide range of 1.0 x 10(-7) to 1.0 x 10(-1) M mercury ion concentrations with an acceptable Nernstian behaviour and a sensitivity of 30.1 ± 0.6 mV/decade. The proposed mercury ion sensor exhibited low detection limit of 1.0 x 10(-8) M and also a fast response time of less than 5 s. In addition, the presented mercury ion sensor has shown an excellent repeatability, reproducibility, stability and selectivity. Moreover, the mercury ion selective electrode based on CuO nanoleaves was tested as an indicator electrode in the potentiometric titration.

Characterization of double oxide system Cu-Cr-O supported on γ-Al2O3

NASA Astrophysics Data System (ADS)

Cherkezova-Zheleva, Z.; Kolev, H.; Krstić, J.; Dimitrov, D.; Ivanov, K.; Loncarević, D.; Jovanović, D.; Mitov, I.

2009-09-01

Series of alumina supported chromium-copper catalysts were prepared by co-impregnation method. The samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and UV-visible diffuse reflectance spectroscopy. Dispersion and porosity was also obtained. The experimental and catalytic test results have drawn a conclusion that an interaction between copper and chromium ions takes place. This interaction is responsible for the enhanced catalytic activity of studied catalysts in reaction of total oxidation of industrial formaldehyde production exhaust gas, which contains CO, dimethyl ether and methanol as main components.

Instrument and method for X-ray diffraction, fluorescence, and crystal texture analysis without sample preparation

NASA Technical Reports Server (NTRS)

Gendreau, Keith (Inventor); Martins, Jose Vanderlei (Inventor); Arzoumanian, Zaven (Inventor)

2010-01-01

An X-ray diffraction and X-ray fluorescence instrument for analyzing samples having no sample preparation includes a X-ray source configured to output a collimated X-ray beam comprising a continuum spectrum of X-rays to a predetermined coordinate and a photon-counting X-ray imaging spectrometer disposed to receive X-rays output from an unprepared sample disposed at the predetermined coordinate upon exposure of the unprepared sample to the collimated X-ray beam. The X-ray source and the photon-counting X-ray imaging spectrometer are arranged in a reflection geometry relative to the predetermined coordinate.

Salt-assistant combustion synthesis of nanocrystalline Nd{sub 2}(Zr{sub 1-x}Sn{sub x}){sub 2}O{sub 7} (0 {<=} x {<=} 1) solid solutions

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

Tong Yuping, E-mail: huabeitong@yahoo.cn; Wang Yanping

2009-11-15

Nanocrystalline Nd{sub 2}(Zr{sub 1-x}Sn{sub x}){sub 2}O{sub 7} series solid solutions were prepared by a convenient salt-assisted combustion process using glycine as fuel. The samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, transmission electron microscopy and high-resolution transmission electron microscopy. The results showed the Zr ion can be partially replaced by Sn ion. The partial substituted products were still single-phase solid solutions and the crystal form remained unchanged. TEM images reveal that the products are composed of well-dispersed square-shaped nanocrystals. The method provides a convenient and low-cost route for the synthesis of nanostructures of oxide materials.

Cellulose aerogels functionalized with polypyrrole and silver nanoparticles: In-situ synthesis, characterization and antibacterial activity.

PubMed

Wan, Caichao; Li, Jian

2016-08-01

Green porous and lightweight cellulose aerogels have been considered as promising candidates to substitute some petrochemical host materials to support various nanomaterials. In this work, waste wheat straw was collected as feedstock to fabricate cellulose hydrogels, and a green inexpensive NaOH/polyethylene glycol solution was used as cellulose solvent. Prior to freeze-drying treatment, the cellulose hydrogels were integrated with polypyrrole and silver nanoparticles by easily-operated in-situ oxidative polymerization of pyrrole using silver ions as oxidizing agent. The tri-component hybrid aerogels were characterized by scanning electron microscope, transmission electron microscope, energy dispersive X-ray spectroscopy, selected area electron diffraction, X-ray photoelectron spectroscopy, and X-ray diffraction. Moreover, the antibacterial activity of the hybrid aerogels against Escherichia coli (Gram-negative), Staphylococcus aureus (Gram-positive) and Listeria monocytogenes (intracellular bacteria) was qualitatively and quantitatively investigated by parallel streak method and determination of minimal inhibitory concentration, respectively. This work provides an example of combining cellulose aerogels with nanomaterials, and helps to develop novel forms of cellulose-based functional materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis and characterization of Ce, Cu co-doped ZnS nanoparticles

NASA Astrophysics Data System (ADS)

Harish, G. S.; Sreedhara Reddy, P.

2015-09-01

Ce, Cu co-doped ZnS nanoparticles were prepared at room temperature using a chemical co-precipitation method. The prepared nanoparticles were characterized by X- ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive analysis of X-rays (EDAX), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and high resolution Raman spectroscopic techniques. Transmission electron microscopy (TEM) and X-ray diffraction studies showed that the diameter of the particles was around 2-3 nm. Broadened XRD peaks revealed the formation of nanoparticles with a face centered cubic (fcc) structure. DRS studies confirmed that the band gap increased with an increase in the dopant concentration. The Raman spectra of undoped and Ce, Cu ions co-doped ZnS nanoparticles showed longitudinal optical mode and transverse optical mode. Compared with the Raman modes (276 and 351 cm-1) of undoped ZnS nanoparticles, the Raman modes of Ce, Cu co- doped ZnS nanoparticles were slightly shifted towards lower frequency. PL spectra of the samples showed remarkable enhancement in the intensity upon doping.

Utilization of fish bone as adsorbent of Fe3+ ion by controllable removal of its carbonaceous component

NASA Astrophysics Data System (ADS)

Nurhadi, M.; Kusumawardani, R.; Widiyowati, I. I.; Wirhanuddin; Nur, H.

2018-05-01

The performance of fish bone to adsorb Fe3+ ion in solution was studied. Powdered fish bone and carbonized fish bone were used as adsorbent. All absorbents were characterized by X-ray diffraction (XRD), IR spectroscopy, nitrogen adsorption, scanning electron microscopy (SEM) and TG analysis. Powdered fish bone and carbonized fish bone were effective as adsorbent for removing Fe3+ ion in solution. The metal adsorptions of Fe3+ ion were 94 and 98% for powdered fish bone and fish bone which carbonized at 400 and 500 °C.

Philip A. Parilla | NREL

Science.gov Websites

atomic layer deposition for applications. He also manages the majority of X-ray characterization equipment at NREL, specifically X-ray diffraction and X-ray fluorescence instrumentation. Additionally, he for EERE's Hydrogen Storage program. He is also an expert in X-ray diffraction and X-ray fluorescence

Synthesis and Characterization of Mixed Iron-Manganese Oxide Nanoparticles and Their Application for Efficient Nickel Ion Removal from Aqueous Samples

PubMed Central

Serra, Antonio; Monteduro, Anna Grazia; Padmanabhan, Sanosh Kunjalukkal; Licciulli, Antonio; Bonfrate, Valentina; Salvatore, Luca; Calcagnile, Lucio

2017-01-01

Mixed iron-manganese oxide nanoparticles, synthesized by a simple procedure, were used to remove nickel ion from aqueous solutions. Nanostructures, prepared by using different weight percents of manganese, were characterized by transmission electron microscopy, selected area diffraction, X-ray diffraction, Raman spectroscopy, and vibrating sample magnetometry. Adsorption/desorption isotherm curves demonstrated that manganese inclusions enhance the specific surface area three times and the pores volume ten times. This feature was crucial to decontaminate both aqueous samples and food extracts from nickel ion. Efficient removal of Ni2+ was highlighted by the well-known dimethylglyoxime test and by ICP-MS analysis and the possibility of regenerating the nanostructure was obtained by a washing treatment in disodium ethylenediaminetetraacetate solution. PMID:28804670

Simulations of X-ray diffraction of shock-compressed single-crystal tantalum with synchrotron undulator sources.

PubMed

Tang, M X; Zhang, Y Y; E, J C; Luo, S N

2018-05-01

Polychromatic synchrotron undulator X-ray sources are useful for ultrafast single-crystal diffraction under shock compression. Here, simulations of X-ray diffraction of shock-compressed single-crystal tantalum with realistic undulator sources are reported, based on large-scale molecular dynamics simulations. Purely elastic deformation, elastic-plastic two-wave structure, and severe plastic deformation under different impact velocities are explored, as well as an edge release case. Transmission-mode diffraction simulations consider crystallographic orientation, loading direction, incident beam direction, X-ray spectrum bandwidth and realistic detector size. Diffraction patterns and reciprocal space nodes are obtained from atomic configurations for different loading (elastic and plastic) and detection conditions, and interpretation of the diffraction patterns is discussed.

Simulations of X-ray diffraction of shock-compressed single-crystal tantalum with synchrotron undulator sources

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

Tang, M. X.; Zhang, Y. Y.; E, J. C.

Polychromatic synchrotron undulator X-ray sources are useful for ultrafast single-crystal diffraction under shock compression. Here, simulations of X-ray diffraction of shock-compressed single-crystal tantalum with realistic undulator sources are reported, based on large-scale molecular dynamics simulations. Purely elastic deformation, elastic–plastic two-wave structure, and severe plastic deformation under different impact velocities are explored, as well as an edge release case. Transmission-mode diffraction simulations consider crystallographic orientation, loading direction, incident beam direction, X-ray spectrum bandwidth and realistic detector size. Diffraction patterns and reciprocal space nodes are obtained from atomic configurations for different loading (elastic and plastic) and detection conditions, and interpretation of themore » diffraction patterns is discussed.« less

Coherent X-ray diffraction imaging of nanoengineered polymeric capsules

NASA Astrophysics Data System (ADS)

Erokhina, S.; Pastorino, L.; Di Lisa, D.; Kiiamov, A. G.; Faizullina, A. R.; Tayurskii, D. A.; Iannotta, S.; Erokhin, V.

2017-10-01

For the first time, nanoengineered polymeric capsules and their architecture have been studied with coherent X-ray diffraction imaging technique. The use of coherent X-ray diffraction imaging technique allowed us to analyze the samples immersed in a liquid. We report about the significant difference between polymeric capsule architectures under dry and liquid conditions.

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

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

Murray, Thomas D.; Johns Hopkins University School of Medicine, Baltimore, MD 21205; Lyubimov, Artem Y.

A highly X-ray-transparent, silicon nitride-based device has been designed and fabricated to harvest protein microcrystals for high-resolution X-ray diffraction data collection using microfocus beamlines and XFELs. Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming themore » challenges intrinsic to microcrystal analysis is to pair so-called ‘fixed-target’ sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

Structural and physical property study of sol-gel synthesized CoFe2-xHoxO4 nano ferrites

NASA Astrophysics Data System (ADS)

Patankar, K. K.; Ghone, D. M.; Mathe, V. L.; Kaushik, S. D.

2018-05-01

CoFe2-xHoxO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20) ferrites were prepared by the suitably modified Sol-Gel technique. X-ray diffraction (XRD) analysis revealed that the substituted samples show phase pure formation till 10% substitution, which is far higher phase pure than the earlier reports. Upon further substitution an inevitable secondary phase of HoFeO3 along with the spinel phase despite regulating synthesis parameters in the sol-gel reaction route. These results are further corroborated more convincingly by room temperature neutron diffraction. Morphological features of the ferrites were studied by Scanning Electron Microscopy (SEM). The magnetic parameters viz. the saturation magnetization (Ms), coercivity (Hc) and remanence (Mr) were determined from room temperature isothermal magnetization. These parameters were found to decrease with increase in Ho substitution. The decrease in magnetization is analyzed in the light of exchange interactions between rare earth and transition metal ions. Magnetostriction measurements revealed interesting results and the presence of a secondary phase was found to be responsible for decreased measu-red magnetostriction values. The solubility limit of Ho in CoFe2O4 lattice is also reflected from the X-ray and neutron diffraction analysis and magnetostriction studies.

Effect of He+ fluence on surface morphology and ion-irradiation induced defect evolution in 7075 aluminum alloys

NASA Astrophysics Data System (ADS)

Ni, Kai; Ma, Qian; Wan, Hao; Yang, Bin; Ge, Junjie; Zhang, Lingyu; Si, Naichao

2018-02-01

The evolution of microstructure for 7075 aluminum alloys with 50 Kev helium ions irradiation were studied by using optical microscopy (OM), scanning electron microscopy (SEM), x-ray diffraction (XRD) and transmission electron microscopy (TEM). The fluences of 1 × 1015, 1 × 1016 and 1 × 1017 ions cm-2 were selected, and irradiation experiments were conducted at room temperatures. The transmission process of He+ ions was simulated by using SRIM software, including distribution of ion ranges, energy losses and atomic displacements. Experimental results show that irradiated pits and micro-cracks were observed on irradiation sample surface, and the size of constituent particles (not including Mg2Si) decreased with the increasing dose. The x-ray diffraction results of the pair of peaks is better resolved in irradiated samples might indicate that the stressed structure consequence due to crystal defects (vacancies and interstitials) after He+ implantation. TEM observation indicated that the density of MgZn2 phase was significantly reduced after helium ion irradiation which is harmful to strength. Besides, the development of compressive stress produced a large amount of dislocation defects in the 1015 ions cm-2 sample. Moreover, higher fluence irradiation produced more dislocations in sample. At fluence of 1016 ions cm-2, dislocation wall formed by dislocation slip and aggregation in the interior of grains, leading to the refinement of these grains. As fluence increased to 1017 ions cm-2, dislocation loops were observed in pinned dislocation. Moreover, dislocation as effective defect sink, irradiation-induced vacancy defects aggregated to these sinks, and resulted in the formation of helium bubbles in dislocation.

Electronic structure, optical and magnetic studies of PLD-grown (Mn, P)-doped ZnO nanocolumns at room temperature

NASA Astrophysics Data System (ADS)

Phan, The-Long; Ho, T. A.; Dang, N. T.; Nguyen, Manh Cuong; Dao, Van-Duong

2017-07-01

We prepared well-aligned Zn1-x Mn x O:yP nanocolumns (x  =  0-0.02, and y  =  0 and 1 mol%) on SiO2/Si(0 0 1) substrates by using pulsed laser deposition (PLD) and then investigated their electronic structure and optical and magnetic properties at room temperature. The analyses of x-ray photoelectron and x-ray absorption fine structure spectra revealed Mn2+ and/or P ions existing in nanocolumns, where Mn2+ ions are situated in the Zn2+ site of the ZnO-wurtzite structure. Although the incorporation of Mn2+ and/or P ions did not form secondary phases, as confirmed by x-ray and electron diffraction patterns, more lattice defects were created, and consequently changed the band-gap energy as well as the electron-phonon interactions in the nanocolumns. Magnetization versus magnetic-field measurements revealed that all the samples exhibited FM order. In particular, the (Mn, P) co-doping with x  =  0.02 and y  =  1 remarkably enhanced the magnetic moment up to 2.92 µ B/Mn. Based on the results obtained from analyzing the electronic structures, UV-Vis absorption and resonant Raman scattering spectra, and theoretical calculations, we believe that the enhancement of the FM order in (Mn, P)-doped ZnO nanocolumns is due to exchange interactions taking place between vacancy-mediated Mn2+ ions.

Probing the thermal stability and the decomposition mechanism of a magnesium-fullerene polymer via X-ray Raman spectroscopy, X-ray diffraction and molecular dynamics simulations.

PubMed

Aramini, Matteo; Niskanen, Johannes; Cavallari, Chiara; Pontiroli, Daniele; Musazay, Abdurrahman; Krisch, Michael; Hakala, Mikko; Huotari, Simo

2016-02-21

We report the microscopic view of the thermal structural stability of the magnesium intercalated fullerene polymer Mg2C60. With the application of X-ray Raman spectroscopy and X-ray diffraction, we study in detail the decomposition pathways of the polymer system upon annealing at temperatures between 300 and 700 °C. We show that there are at least two energy scales involved in the decomposition reaction. Intermolecular carbon bonds, which are responsible for the formation of a 2D fullerene polymer, are broken with a relatively modest thermal energy, while the long-range order of the original polymer remains intact. With an increased thermal energy, the crystal structure in turn is found to undergo a transition to a novel intercalated cubic phase that is stable up to the highest temperature studied here. The local structure surrounding magnesium ions gets severely modified close to, possibly at, the phase transition. We used density functional theory based calculations to study the thermodynamic and kinetic aspects of the collapse of the fullerene network, and to explain the intermediate steps as well as the reaction pathways in the break-up of this peculiar C60 intermolecular bonding architecture.

Local surrounding of Mn in LaMn 1-xCo xO 3 compounds by means of EXAFS on Mn-K

NASA Astrophysics Data System (ADS)

Procházka, Vít; Sikora, Marcin; Kapusta, Czeslaw; Štěpánková, Helena; Chlan, Vojtěch; Knížek, Karel; Jirák, Zdeněk

2010-05-01

A systematic study of LaMn 1-xCo xO 3 perovskite series by means of X-ray absorption spectroscopy in the extended X-ray absorption fine structure (EXAFS) range of the K-absorption edge of Mn is reported. The Mn-K edge absorption measurements in the EXAFS region were performed to study the local surrounding of Mn ions. Polycrystalline powder samples of LaMn 1-xCo xO 3 ( x=0, 0.02; 0.2; 0.4; 0.5; 0.6; 0.8) prepared by solid-state reaction were used. The EXAFS spectra were analyzed with the FEFF8 computer program. The Mn-O distances of Mn to the nearest oxygen surroundings were evaluated for the samples in the series and compared with the Co-O distances obtained by EXAFS in V. Procházka et al., JMMM 310 (2007) 197 and with results of X-ray powder diffraction in C. Autret, J. Phys. Condens. Matter 17 (2005) 1601.

Effects of neutron and gamma radiation on lithium-ion batteries

NASA Astrophysics Data System (ADS)

Qiu, Jie; He, Dandan; Sun, Mingzhai; Li, Shimeng; Wen, Cun; Hattrick-Simpers, Jason; Zheng, Yuan F.; Cao, Lei

2015-02-01

Radiation induced deterioration in the performance of lithium-ion (Li-ion) batteries can result in functional failures of electronic devices in modern electronic systems. The stability of the Li-ion battery under a radiation environment is of crucial importance. In this work, the surface morphology of the cathode material of a commercial Li-ion battery before and after neutron and gamma ray irradiation was characterized by atomic force microscopy (AFM). We found growth in the particle size of the cathode material in the range of 36-45% as a result of the irradiation. In addition, X-ray diffraction (XRD) patterns revealed a disordering of the crystal structure occurring in the post-irradiation sample. All of these led to a 8.4% capacity loss of the battery for the maximum received irradiation dose (2.744 Mrad) at post-irradiation. The effects of the radiation on the Li-ion battery are discussed in this paper.

Adsorption of Pb2+ ions on novel ternary nanocomposite of tin, iron and titania

NASA Astrophysics Data System (ADS)

Rehman, Mahfooz ur; Rehman, Wajid; Waseem, Muhammad; Haq, Sirajul; Hussain Shah, Khizar; Kang, Peng

2018-02-01

In this study, ternary nanocomposite (TNC) was synthesized by microemulsion method by taking Sn, Ti and Fe in (1:1:1) molar ratio. The BET surface area and pore size were measured by nitrogen adsorption method. The morphological features of TNC like particle size, elemental percentage and crystallite size were studied by scanning electron microscopy (SEM), energy dispersive x-rays (EDX) and x-rays diffraction (XRD) respectively, whereas the surface functional groups were detected by Fourier Transform Infrared (FTIR) spectroscopy. The crystallite size was found to be 11 nm, calculated from FWHM of diffraction peak with relative intensity 100%. For the thermal stability of TNC, thermogravimetric analysis (TGA) was performed. Batch adsorption tests were used for the removal of Pb2+ ions from aqueous solutions. The maximum adsorption capacity in this study was found to be 79.56 mg g-1 at 40 °C which is promising than the values reported in the literature. Based on the regression coefficient (r 2), the adsorption data was found well fitted to the Langmuir as compared to Freundlich model. The exchange of a single proton with every Pb2+ ion was calculated. Thermodynamic parameters were indicative for the sorption process to be endothermic and spontaneous.

Hydrogen bonded nonlinear optical γ-glycine: Crystal growth and characterization

NASA Astrophysics Data System (ADS)

Narayana Moolya, B.; Jayarama, A.; Sureshkumar, M. R.; Dharmaprakash, S. M.

2005-07-01

Single crystals of γ-glycine(GG) were grown by solvent evaporation technique from a mixture of aqueous solutions of glycine and ammonium nitrate at ambient temperature. X-ray diffraction, thermogravimetric/differential thermal analysis, Fourier transform infrared spectral techniques were employed to characterize the crystal. The lattice parameters were calculated and they agree well with the reported values. GG exists as dipolar ions in which the carboxyl group is present as a carboxylate ion and the amino group as an ammonium ion. Due to this dipolar nature, glycine has a high decomposition temperature. The UV cutoff of GG is below 300 nm and has a wide transparency window, which is suitable for second harmonic generation of laser in the blue region. Nonlinear optical characteristics of GG were studied using Q switched Nd:YAG laser ( λ=1064 nm). The second harmonic generation conversion efficiency of GG is 1.5 times that of potassium dihydrogen phosphate . The X-ray diffraction and Fourier transform infrared spectral studies show the presence of strong hydrogen bonds which create and stabilize the crystal structure in GG. The main contributions to the nonlinear optical properties in GG results from the presence of the hydrogen bond and from the vibrational part due to very intense infrared bands of the hydrogen bond vibrations. GG is thermally stable up to 441 K.

X-Ray Structure determination of the Glycine Cleavage System Protein H of Mycobacterium tuberculosis Using An Inverse Compton Synchrotron X-Ray Source

PubMed Central

Abendroth, Jan; McCormick, Michael S.; Edwards, Thomas E.; Staker, Bart; Loewen, Roderick; Gifford, Martin; Rifkin, Jeff; Mayer, Chad; Guo, Wenjin; Zhang, Yang; Myler, Peter; Kelley, Angela; Analau, Erwin; Hewitt, Stephen Nakazawa; Napuli, Alberto J.; Kuhn, Peter; Ruth, Ronald D.; Stewart, Lance J.

2010-01-01

Structural genomics discovery projects require ready access to both X-ray and NMR instrumentation which support the collection of experimental data needed to solve large numbers of novel protein structures. The most productive X-ray crystal structure determination laboratories make extensive frequent use of tunable synchrotron X-ray light to solve novel structures by anomalous diffraction methods. This requires that frozen cryo-protected crystals be shipped to large government-run synchrotron facilities for data collection. In an effort to eliminate the need to ship crystals for data collection, we have developed the first laboratory-scale synchrotron light source capable of performing many of the state-of-the-art synchrotron applications in X-ray science. This Compact Light Source is a first-in-class device that uses inverse Compton scattering to generate X-rays of sufficient flux, tunable wavelength and beam size to allow high-resolution X-ray diffraction data collection from protein crystals. We report on benchmarking tests of X-ray diffraction data collection with hen egg white lysozyme, and the successful high-resolution X-ray structure determination of the Glycine cleavage system protein H from Mycobacterium tuberculosis using diffraction data collected with the Compact Light Source X-ray beam. PMID:20364333

X-ray induced chemical reaction revealed by in-situ X-ray diffraction and scanning X-ray microscopy in 15 nm resolution (Conference Presentation)

NASA Astrophysics Data System (ADS)

Ge, Mingyuan; Liu, Wenjun; Bock, David; De Andrade, Vincent; Yan, Hanfei; Huang, Xiaojing; Marschilok, Amy; Takeuchi, Esther; Xin, Huolin; Chu, Yong S.

2016-09-01

The detection sensitivity of synchrotron-based X-ray techniques has been largely improved due to the ever increasing source brightness, which have significantly advanced ex-situ and in-situ research for energy materials, such as lithium-ion batteries. However, the strong beam-matter interaction arisen from the high beam flux can significantly modify the material structure. The parasitic beam-induced effect inevitably interferes with the intrinsic material property, which brings difficulties in interpreting experimental results, and therefore requires comprehensive evaluation. Here we present a quantitative in-situ study of the beam-effect on one electrode material Ag2VO2PO4 using four different X-ray probes with different radiation dose rate. The material system we reported exhibits interesting and reversible radiation-induced thermal and chemical reactions, which was further evaluated under electron microscopy to illustrate the underlying mechanism. The work we presented here will provide a guideline in using synchrotron X-rays to distinguish the materials' intrinsic behavior from extrinsic structure changed induced by X-rays, especially in the case of in-situ and operando study where the materials are under external field of either temperature or electric field.

Anti-contamination device for cryogenic soft X-ray diffraction microscopy

DOE PAGES

Huang, Xiaojing; Miao, Huijie; Nelson, Johanna; ...

2011-05-01

Cryogenic microscopy allows one to view frozen hydrated biological and soft matter specimens with good structural preservation and a high degree of stability against radiation damage. We describe a liquid nitrogen-cooled anti-contamination device for cryogenic X-ray diffraction microscopy. The anti-contaminator greatly reduces the buildup of ice layers on the specimen due to condensation of residual water vapor in the experimental vacuum chamber. We show by coherent X-ray diffraction measurements that this leads to fivefold reduction of background scattering, which is important for far-field X-ray diffraction microscopy of biological specimens.

Swift heavy ion irradiation studies of GdFeO3 orthoferrite thin films

NASA Astrophysics Data System (ADS)

Kaur, Pawanpreet; Pandit, Rabia; Sharma, K. K.; Kumar, Ravi

2018-04-01

Thin films of GdFeO3, orthoferrite have been grown on MgO (001) substrate by pulsed laser deposition technique (PLD) to investigate the effect of swift heavy ion irradiation on their structural and magnetic properties. Thin films were irradiated with 200 MeV Ag15+ ions with fluence of 1×1011ions/cm2. The results of X-ray diffraction, atomic force microscopy and vibrating sample magnetometer characterization techniques are found to be different for the irradiated film from that of the pristine sample. The modifications in the irradiated samples are explained in terms of the ion-induced disorder.

Synthesis of ferrites obtained from heavy metal solutions using wet method.

PubMed

Yang, Ji; Peng, Juan; Liu, Kaicheng; Guo, Rui; Xu, Dianliang; Jia, Jinping

2007-05-08

Wet method was employed to the treatment of heavy metal-contaminated wastewater, and Zn(x)Fe(3-x)O(4), Ni(x)Fe(3-x)O(4) and Cr(x)Fe(3-x)O(4) (0Cr(3+) and the influence of the three ions on sample thermostability is Zn(2+)>Ni(2+)>Cr(3+).

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

Xu, Gui-Liang; Chen, Zonghai; Zhong, Gui-Ming

Sodium-ion batteries are promising alternatives to lithium-ion batteries for large-scale applications. However, the low capacity and poor rate capability of existing anodes for sodium-ion batteries are bottlenecks for future developments. Here, we report a high performance nanostructured anode material for sodium-ion batteries that is fabricated by high energy ball milling to form black phosphorus/Ketjenblack–multiwalled carbon nanotubes (BPC) composite. With this strategy, the BPC composite with a high phosphorus content (70 wt %) could deliver a very high initial Coulombic efficiency (>90%) and high specific capacity with excellent cyclability at high rate of charge/discharge (~1700 mAh g–1 after 100 cycles atmore » 1.3 A g–1 based on the mass of P). In situ electrochemical impedance spectroscopy, synchrotron high energy X-ray diffraction, ex situ small/wide-angle X-ray scattering, high resolution transmission electronic microscopy, and nuclear magnetic resonance were further used to unravel its superior sodium storage performance. The scientific findings gained in this work are expected to serve as a guide for future design on high performance anode material for sodium-ion batteries.« less

Observation of electromigration in a Cu thin line by in situ coherent x-ray diffraction microscopy

NASA Astrophysics Data System (ADS)

Takahashi, Yukio; Nishino, Yoshinori; Furukawa, Hayato; Kubo, Hideto; Yamauchi, Kazuto; Ishikawa, Tetsuya; Matsubara, Eiichiro

2009-06-01

Electromigration (EM) in a 1-μm-thick Cu thin line was investigated by in situ coherent x-ray diffraction microscopy (CXDM). Characteristic x-ray speckle patterns due to both EM-induced voids and thermal deformation in the thin line were observed in the coherent x-ray diffraction patterns. Both parts of the voids and the deformation were successfully visualized in the images reconstructed from the diffraction patterns. This result not only represents the first demonstration of the visualization of structural changes in metallic materials by in situ CXDM but is also an important step toward studying the structural dynamics of nanomaterials using x-ray free-electron lasers in the near future.

Doping effect on the structural properties of Cu1-x(Ni, Zn, Al and Fe)xO samples (0

NASA Astrophysics Data System (ADS)

Amaral, J. B.; Araujo, R. M.; Pedra, P. P.; Meneses, C. T.; Duque, J. G. S.; dos S. Rezende, M. V.

2016-09-01

In this work, the effect of insertion of transition metal, TM (=Ni, Zn, Al and Fe), ions in Cu1-xTMxO samples (0

Eco-friendly preparation of large-sized graphene via short-circuit discharge of lithium primary battery.

PubMed

Kang, Shaohong; Yu, Tao; Liu, Tingting; Guan, Shiyou

2018-02-15

We proposed a large-sized graphene preparation method by short-circuit discharge of the lithium-graphite primary battery for the first time. LiC x is obtained through lithium ions intercalation into graphite cathode in the above primary battery. Graphene was acquired by chemical reaction between LiC x and stripper agents with dispersion under sonication conditions. The gained graphene is characterized by Raman spectrum, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Atomic force microscope (AFM) and Scanning electron microscopy (SEM). The results indicate that the as-prepared graphene has a large size and few defects, and it is monolayer or less than three layers. The quality of graphene is significant improved compared to the reported electrochemical methods. The yield of graphene can reach 8.76% when the ratio of the H 2 O and NMP is 3:7. This method provides a potential solution for the recycling of waste lithium ion batteries. Copyright © 2017 Elsevier Inc. All rights reserved.

Note: application of a pixel-array area detector to simultaneous single crystal X-ray diffraction and X-ray absorption spectroscopy measurements.

PubMed

Sun, Cheng-Jun; Zhang, Bangmin; Brewe, Dale L; Chen, Jing-Sheng; Chow, G M; Venkatesan, T; Heald, Steve M

2014-04-01

X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are two main x-ray techniques in synchrotron radiation facilities. In this Note, we present an experimental setup capable of performing simultaneous XRD and XAS measurements by the application of a pixel-array area detector. For XRD, the momentum transfer in specular diffraction was measured by scanning the X-ray energy with fixed incoming and outgoing x-ray angles. By selecting a small fixed region of the detector to collect the XRD signal, the rest of the area was available for collecting the x-ray fluorescence for XAS measurements. The simultaneous measurement of XRD and X-ray absorption near edge structure for Pr0.67Sr0.33MnO3 film was demonstrated as a proof of principle for future time-resolved pump-probe measurements. A static sample makes it easy to maintain an accurate overlap of the X-ray spot and laser pump beam.

X-Ray Diffraction Wafer Mapping Method for Rhombohedral Super-Hetero-Epitaxy

NASA Technical Reports Server (NTRS)

Park, Yoonjoon; Choi, Sang Hyouk; King, Glen C.; Elliott, James R.; Dimarcantonio, Albert L.

2010-01-01

A new X-ray diffraction (XRD) method is provided to acquire XY mapping of the distribution of single crystals, poly-crystals, and twin defects across an entire wafer of rhombohedral super-hetero-epitaxial semiconductor material. In one embodiment, the method is performed with a point or line X-ray source with an X-ray incidence angle approximating a normal angle close to 90 deg, and in which the beam mask is preferably replaced with a crossed slit. While the wafer moves in the X and Y direction, a narrowly defined X-ray source illuminates the sample and the diffracted X-ray beam is monitored by the detector at a predefined angle. Preferably, the untilted, asymmetric scans are of {440} peaks, for twin defect characterization.

Diffraction based method to reconstruct the spectrum of the Thomson scattering x-ray source

NASA Astrophysics Data System (ADS)

Chi, Zhijun; Yan, Lixin; Zhang, Zhen; Zhou, Zheng; Zheng, Lianmin; Wang, Dong; Tian, Qili; Wang, Wei; Nie, Zan; Zhang, Jie; Du, Yingchao; Hua, Jianfei; Shi, Jiaru; Pai, Chihao; Lu, Wei; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

2017-04-01

As Thomson scattering x-ray sources based on the collision of intense laser and relativistic electrons have drawn much attention in various scientific fields, there is an increasing demand for the effective methods to reconstruct the spectrum information of the ultra-short and high-intensity x-ray pulses. In this paper, a precise spectrum measurement method for the Thomson scattering x-ray sources was proposed with the diffraction of a Highly Oriented Pyrolytic Graphite (HOPG) crystal and was demonstrated at the Tsinghua Thomson scattering X-ray source. The x-ray pulse is diffracted by a 15 mm (L) ×15 mm (H)× 1 mm (D) HOPG crystal with 1° mosaic spread. By analyzing the diffraction pattern, both x-ray peak energies and energy spectral bandwidths at different polar angles can be reconstructed, which agree well with the theoretical value and simulation. The higher integral reflectivity of the HOPG crystal makes this method possible for single-shot measurement.

Diffraction based method to reconstruct the spectrum of the Thomson scattering x-ray source.

PubMed

Chi, Zhijun; Yan, Lixin; Zhang, Zhen; Zhou, Zheng; Zheng, Lianmin; Wang, Dong; Tian, Qili; Wang, Wei; Nie, Zan; Zhang, Jie; Du, Yingchao; Hua, Jianfei; Shi, Jiaru; Pai, Chihao; Lu, Wei; Huang, Wenhui; Chen, Huaibi; Tang, Chuanxiang

2017-04-01

As Thomson scattering x-ray sources based on the collision of intense laser and relativistic electrons have drawn much attention in various scientific fields, there is an increasing demand for the effective methods to reconstruct the spectrum information of the ultra-short and high-intensity x-ray pulses. In this paper, a precise spectrum measurement method for the Thomson scattering x-ray sources was proposed with the diffraction of a Highly Oriented Pyrolytic Graphite (HOPG) crystal and was demonstrated at the Tsinghua Thomson scattering X-ray source. The x-ray pulse is diffracted by a 15 mm (L) ×15 mm (H)× 1 mm (D) HOPG crystal with 1° mosaic spread. By analyzing the diffraction pattern, both x-ray peak energies and energy spectral bandwidths at different polar angles can be reconstructed, which agree well with the theoretical value and simulation. The higher integral reflectivity of the HOPG crystal makes this method possible for single-shot measurement.

Facile solvothermal synthesis of cube-like Ag@AgCl: a highly efficient visible light photocatalyst

NASA Astrophysics Data System (ADS)

Han, Lei; Wang, Ping; Zhu, Chengzhou; Zhai, Yueming; Dong, Shaojun

2011-07-01

In this paper, a stable and highly efficient plasmonic photocatalyst, Ag@AgCl, with cube-like morphology, has been successfully prepared via a simple hydrothermal method. Using methylene dichloride as chlorine source in the synthesis can efficiently control the morphology of Ag@AgCl, due to the low release rate of chloride ions. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra were used to characterize the obtained product. The photocatalytic activity of the obtained product was evaluated by the photodegradation of methyl orange (MO) under visible light irradiation, and it was found, interestingly, that Ag@AgCl exhibits high visible light photocatalytic activity and good stability.In this paper, a stable and highly efficient plasmonic photocatalyst, Ag@AgCl, with cube-like morphology, has been successfully prepared via a simple hydrothermal method. Using methylene dichloride as chlorine source in the synthesis can efficiently control the morphology of Ag@AgCl, due to the low release rate of chloride ions. Scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectra were used to characterize the obtained product. The photocatalytic activity of the obtained product was evaluated by the photodegradation of methyl orange (MO) under visible light irradiation, and it was found, interestingly, that Ag@AgCl exhibits high visible light photocatalytic activity and good stability. Electronic supplementary information (ESI) available: SEM images of the AgCl samples synthesized by changing the addition amount of PVP and AgNO3. See DOI: 10.1039/c1nr10247h

Gas gun shock experiments with single-pulse x-ray phase contrast imaging and diffraction at the Advanced Photon Source

NASA Astrophysics Data System (ADS)

Luo, S. N.; Jensen, B. J.; Hooks, D. E.; Fezzaa, K.; Ramos, K. J.; Yeager, J. D.; Kwiatkowski, K.; Shimada, T.

2012-07-01

The highly transient nature of shock loading and pronounced microstructure effects on dynamic materials response call for in situ, temporally and spatially resolved, x-ray-based diagnostics. Third-generation synchrotron x-ray sources are advantageous for x-ray phase contrast imaging (PCI) and diffraction under dynamic loading, due to their high photon fluxes, high coherency, and high pulse repetition rates. The feasibility of bulk-scale gas gun shock experiments with dynamic x-ray PCI and diffraction measurements was investigated at the beamline 32ID-B of the Advanced Photon Source. The x-ray beam characteristics, experimental setup, x-ray diagnostics, and static and dynamic test results are described. We demonstrate ultrafast, multiframe, single-pulse PCI measurements with unprecedented temporal (<100 ps) and spatial (˜2 μm) resolutions for bulk-scale shock experiments, as well as single-pulse dynamic Laue diffraction. The results not only substantiate the potential of synchrotron-based experiments for addressing a variety of shock physics problems, but also allow us to identify the technical challenges related to image detection, x-ray source, and dynamic loading.

Synthesis of Co2+-doped Fe2O3 photocatalyst for degradation of pararosaniline dye

NASA Astrophysics Data System (ADS)

Suresh, R.; Giribabu, K.; Manigandan, R.; Mangalaraja, R. V.; Solorza, Jorge Yanez; Stephen, A.; Narayanan, V.

2017-06-01

In this paper, x (=2, 5, 7 and 10mol%) Co2+-doped Fe2O3 (xCo:Fe2O3) nanoparticles with enhanced photocatalytic activity have been reported. xCo:Fe2O3 nanoparticles were successfully prepared by co-precipitation followed thermal decomposition method. The structural, optical and morphological properties of the prepared samples were studied by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), diffuse reflectance (DR) UV-visible absorption spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The obtained results revealed that Co2+ ions were well doped within the lattices of Fe2O3. Also, Co2+ ions suppress the formation of the most stable α- Fe2O3 and stabilize less stable γ-Fe2O3 at 450 °C. The photocatalytic activity of xCo:Fe2O3 was examined by using pararosaniline (PR) dye. It was found that photocatalytic degradation of PR depends on dopant concentration (Co2+ ions). Relatively, the highest photocatalytic activity was observed for 5%Co:Fe2O3 nanoparticles. The plausible photocatalytic degradation pathway of PR at xCo:Fe2O3 surface has also been proposed.

X-ray and neutron diffraction studies of crystallinity in hydroxyapatite coatings.

PubMed

Girardin, E; Millet, P; Lodini, A

2000-02-01

To standardize industrial implant production and make comparisons between different experimental results, we have to be able to quantify the crystallinity of hydroxyapatite. Methods of measuring crystallinity ratio were developed for various HA samples before and after plasma spraying. The first series of methods uses X-ray diffraction. The advantage of these methods is that X-ray diffraction equipment is used widely in science and industry. In the second series, a neutron diffraction method is developed and the results recorded are similar to those obtained by the modified X-ray diffraction methods. The advantage of neutron diffraction is the ability to obtain measurements deep inside a component. It is a nondestructive method, owing to the very low absorption of neutrons in most materials. Copyright 2000 John Wiley & Sons, Inc.

X-ray Diffraction Gratings for Astrophysics

NASA Astrophysics Data System (ADS)

Paerels, Frits

2010-12-01

Over the past year, we have celebrated the tenth anniversary of the Chandra and XMM-Newton X-ray observatories. Both carry powerful, novel diffraction grating spectrometers, which have opened true X-ray spectroscopy for astrophysics. I will describe the design and operation of these instruments, as the background to some of the beautiful results they have produced. But these designs do not exhaust the versatility and essential simplicity of diffraction grating spectrometers, and I will discuss applications for the International X-ray Observatory IXO.

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.

Amorphization of Ta2O5 under swift heavy ion irradiation

NASA Astrophysics Data System (ADS)

Cusick, Alex B.; Lang, Maik; Zhang, Fuxiang; Sun, Kai; Li, Weixing; Kluth, Patrick; Trautmann, Christina; Ewing, Rodney C.

2017-09-01

Crystalline Ta2O5 powder is shown to amorphize under 2.2 GeV 197Au ion irradiation. Synchrotron X-ray diffraction (XRD), Raman spectroscopy, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) were used to characterize the structural transition from crystalline to fully-amorphous. Based on Rietveld refinement of XRD data, the initial structure is orthorhombic (P2mm) with a very large unit cell (a = 6.20, b = 40.29, c = 3.89 Å; V = 971.7 Å3), ideally containing 22 Ta and 55 O atoms. At a fluence of approximately 3 × 1011 ions/cm2, a diffuse amorphous background becomes evident, increasing in intensity relative to diffraction maxima until full amorphization is achieved at approximately 3 × 1012 ions/cm2. An anisotropic distortion of the orthorhombic structure occurred during the amorphization process, with an approximately constant unit cell volume. The amorphous phase fraction as a function of fluence was determined, yielding a trend that is consistent with a direct-impact model for amorphization. SAXS and TEM data indicate that ion tracks exhibit a core-shell morphology. Raman data show that the amorphous phase is comprised of TaO6 and TaO5 coordination-polyhedra in contrast to the TaO6 and TaO7 units that exist in crystalline Ta2O5. Analysis of Raman data shows that oxygen-deficiency increases with fluence, indicating a loss of oxygen that leads to an estimated final stoichiometry of Ta2O4.2 at a fluence of 1 × 1013 ions/cm2.

X-Ray Sum Frequency Diffraction for Direct Imaging of Ultrafast Electron Dynamics

NASA Astrophysics Data System (ADS)

Rouxel, Jérémy R.; Kowalewski, Markus; Bennett, Kochise; Mukamel, Shaul

2018-06-01

X-ray diffraction from molecules in the ground state produces an image of their charge density, and time-resolved x-ray diffraction can thus monitor the motion of the nuclei. However, the density change of excited valence electrons upon optical excitation can barely be monitored with regular diffraction techniques due to the overwhelming background contribution of the core electrons. We present a nonlinear x-ray technique made possible by novel free electron laser sources, which provides a spatial electron density image of valence electron excitations. The technique, sum frequency generation carried out with a visible pump and a broadband x-ray diffraction pulse, yields snapshots of the transition charge densities, which represent the electron density variations upon optical excitation. The technique is illustrated by ab initio simulations of transition charge density imaging for the optically induced electronic dynamics in a donor or acceptor substituted stilbene.

Solid-state chelation of metal ions by ethylenediaminetetraacetate intercalated in a layered double hydroxide.

PubMed

Tarasov, Konstantin A; O'Hare, Dermot; Isupov, Vitaly P

2003-03-24

The solid-state chelation of transition metal ions (Co(2+), Ni(2+), and Cu(2+)) from aqueous solutions into the lithium aluminum layered double hydroxide ([LiAl(2)(OH)(6)]Cl x 0.5H(2)O or LDH) which has been pre-intercalated with EDTA (ethylenediaminetetraacetate) ligand has been investigated. The intercalated metal cations form [M(edta)](2)(-) complexes between the LDH layers as indicated by elemental analysis, powder X-ray diffraction, and IR and UV-vis spectroscopies. If metal chloride or nitrate salts are used in the reaction with the LDH then co-intercalation of either the Cl(-) or NO(3)(-) anions is observed. In the case of metal acetate salts the cations intercalate without the accompanying anion. This can be explained by the different intercalation selectivity of the anions in relation to the LDH. In the latter case the introduction of the positive charge into LDH structure was compensated for by the release from the solid of the equivalent quantity of lithium and hydrogen cations. Time-resolved in-situ X-ray diffraction measurements have revealed that the chelation/intercalation reactions proceed very quickly. The rate of the reaction found for nickel acetate depends on concentration as approximately k[Ni(Ac)(2)](3).

Crystal growth of carbonate apatite using a CaCO3 flux.

PubMed

Suetsugu, Y; Tanaka, J

1999-09-01

Single crystals of carbonate apatite were grown using a CaCO3 flux under an Ar gas pressure of 55 MPa. The crystals obtained were observed by scanning electron microscopy, optical microscopy and X-ray diffraction. Electron probe microanalyses and thermal analyses were performed. CO3 ions in planar triangle form replaced both OH sites and PO4 tetrahedral sites in the apatite structure: in particular, the OH sites were perfectly substituted by CO3 ions using this method.

Advanced hydrogen electrode for hydrogen-bromide battery

NASA Technical Reports Server (NTRS)

Kosek, Jack A.; Laconti, Anthony B.

1987-01-01

Binary platinum alloys are being developed as hydrogen electrocatalysts for use in a hydrogen bromide battery system. These alloys were varied in terms of alloy component mole ratio and heat treatment temperature. Electrocatalyst evaluation, performed in the absence and presence of bromide ion, includes floating half cell polarization studies, electrochemical surface area measurements, X ray diffraction analysis, scanning electron microscopy analysis and corrosion measurements. Results obtained to date indicate a platinum rich alloy has the best tolerance to bromide ion poisoning.

Phase equilibria and crystal chemistry of rubidium niobates and rubidium tantalates

NASA Technical Reports Server (NTRS)

Minor, D. B.; Roth, R. S.; Parker, H. S.; Brower, W. S.

1977-01-01

The phase equilibria relations and crystal chemistry of portions of the Rb2O-Nb2O5 and Rb2O-Ta2O5 systems were investigated for structures potentially useful as ionic conductors. A hexagonal tungsten bronze-type (HTB) structure was found in both systems as well as three hexagonal phases with mixed HTB-pyrochlore type structures. Ion exchange experiments between various alkali ions are described for several phases. Unit cell dimensions and X-ray diffraction powder patterns are reported.

Effect of La3+ Substitution on Electric, Dielectric and Magnetic Properties of Cobalt Nano-Ferrite

NASA Astrophysics Data System (ADS)

Kumar, Pawan; Singh, M.

2011-07-01

Ultrafine particles of CoLaxFe2-xO4 (x = 0, 0.20) were prepared by using co-precipitation method. X-ray diffraction studies show that the samples have cubic spinel structure and average crystallite size of x = 0 and x = 0.2 are 49.84 nm and 27.73 nm respectively. Dielectric and magnetic properties have been studied by impedance analyzer and magnetic properties of the ferrite system were studied using VSM respectively. La3+ ions modulate significantly the electric, dielectric and magnetic properties of cobalt spinel ferrites.

Synthesis, crystal structure and antitumor activities of water soluble protonated salt of 20(S)-camptothecin

NASA Astrophysics Data System (ADS)

Lu, Wen; Wang, Yong; Wang, Luna; Zhao, Fengyi; Yang, Shilong; Xi, Chengjie; Yang, Yu; Xu, Li; Chi, Xingwei

2018-03-01

A water soluble camptothecin protonated salt has been synthesized; single crystals were grown by slow evaporation solution growth technique at room temperature and characterized by single crystal X-ray diffraction, FT-IR and 1H NMR. The CPT was protonated as (CPT+H+) cations, the cationic protonation occurred on the N position at pyridine group, which fromed a cation-anion compound with perchlorate ion that determined by X-Ray diffraction. Its activities against Hela (cervix), MCF-7 (breast), A549 (lung), HepG2 (liver) and HUVEC (umbilical vein, normal cell) were investigated. The toxicity of the protonated salt was slightly lower than camptothecin. IC50 values of 7.01 μM against HepG-2 cell, 8.61 μM against A549 cell, 17.82 μM against McF-7 cell, all of them are lower than the IC50 values of CPT against these cells except Hela cell.

Synchrotron x-ray diffraction studies of the structural properties of electrode materials in operating battery cells

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

Thurston, T.R.; Jisrawi, N.M.; Mukerjee, S.

Hard x rays from a synchrotron source were utilized in diffraction experiments which probed the bulk of electrode materials while they were operating {ital in} {ital situ} in battery cells. Two technologically relevant electrode materials were examined; an {ital AB}{sub 2}-type anode in a nickel{endash}metal{endash}hydride cell and a LiMn{sub 2}O{sub 4} cathode in a Li-ion {open_quote}{open_quote}rocking chair{close_quote}{close_quote} cell. Structural features such as lattice expansions and contractions, phase transitions, and the formation of multiple phases were easily observed as either hydrogen or lithium was electrochemically intercalated in and out of the electrode materials. The relevance of this technique for future studiesmore » of battery electrode materials is discussed. {copyright} {ital 1996 American Institute of Physics.}« less

Purification, crystallization and preliminary X-ray analysis of urease from pigeon pea (Cajanus cajan)

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

Balasubramanian, Anuradha; Ponnuraj, Karthe, E-mail: pkarthe@hotmail.com

Urease from pigeon pea was purified and crystallized and X-ray diffraction data were collected at 2.5 Å resolution. Urease is a seed protein that is common to most Leguminosae. It also occurs in many bacteria, fungi and several species of yeast. Urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, thus allowing organisms to use exogenous and internally generated urea as a nitrogen source. Urease from pigeon pea seeds has been purified to electrophoretic homogeneity using a series of steps involving ammonium sulfate fractionation, acid precipitation, ion-exchange and size-exclusion chromatography techniques. The pigeon pea urease was crystallized andmore » the resulting crystals diffracted to 2.5 Å resolution. The crystals belong to the rhombohedral space group R32, with unit-cell parameters a = b = 176.29, c = 346.44 Å.« less

Symmetry and charge order in Fe2OBO3 studied through polarized resonant x-ray diffraction

NASA Astrophysics Data System (ADS)

Bland, S. R.; Angst, M.; Adiga, S.; Scagnoli, V.; Johnson, R. D.; Herrero-Martín, J.; Hatton, P. D.

2010-09-01

Bond valence sum calculations have previously suggested that iron oxyborate exhibits charge order of the Fe ions with integer 2+/3+ valence states. Meanwhile transition metal oxides typically show much smaller, fractional charge disproportionations. Using resonant x-ray diffraction at the iron K edge, we find resonant features which are much larger than those ordinarily observed in charge ordered oxides. Simulations were subsequently performed using a cluster-based, monoelectronic code. The nanoscale domain structure prevents precise fitting; nevertheless the simulations confirm the diagonal charge order symmetry, as well as the unusually large charge disproportionation. We have demonstrated the conversion of linearly to nonlinearly polarized light and vice versa through full polarization analysis. Simulations show that this effect principally results from interference between the isotropic and anisotropic scattering terms. This mechanism is likely to account for similar observations in alternative systems.

Crystal Structure of the Caged Magnetic Compound DyFe2Zn20 at Low Temperature Magnetic Ordering State

NASA Astrophysics Data System (ADS)

Kishii, Nobuya; Tateno, Shota; Ohashi, Masashi; Isikawa, Yosikazu

We have carried out X-ray powder diffraction and thermal expansion measurements of the caged magnetic compound DyFe2Zn20. 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 at 14 K correspond to Bragg reflections of the cubic structural models not only at room temperature paramagnetic state but also at low temperature magnetic ordering state. Although the temperature change of the lattice constant is isotropic, an anomalous behavior was observed in the thermal expansion coefficient around 15 K, while the anomaly around TC = 53 K is not clear. The results indicate that the volume change is not caused by the ferromagnetic interaction between Fe and Dy but by the exchange interaction between two Dy ions.

Irradiation induced formation of VN in CrN thin films

NASA Astrophysics Data System (ADS)

Novaković, M.; Popović, M.; Zhang, K.; Mitrić, M.; Bibić, N.

2015-09-01

Reactively sputtered CrN layer, deposited on Si(1 0 0) wafer, was implanted at room temperature with 80-keV V+ ions to the fluence of 2 × 1017 ions/cm2. After implantation the sample was annealed in a vacuum, for 2 h at 700 °C. The microstructure and chemical composition of CrN films was investigated using Rutherford backscattering spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and cross-sectional transmission electron microscopy (conventional and high-resolution), together with fast Fourier transformation analyses. It was found that vanadium atoms are distributed in the sub-surface region of CrN layer, with the maximum concentration at ∼20 nm. After annealing the formation of VN nanoparticles was observed. The nanoparticles are spherical shaped with a size of 8-20 nm in diameter.

Development of an adaptable coherent x-ray diffraction microscope with the emphasis on imaging hydrated specimens.

PubMed

Nam, Daewoong; Park, Jaehyun; Gallagher-Jones, Marcus; Shimada, Hiroki; Kim, Sangsoo; Kim, Sunam; Kohmura, Yoshiki; Ishikawa, Tetsuya; Song, Changyong

2013-11-01

This paper describes the development of a versatile coherent x-ray diffraction microscope capable of imaging biological specimens in solution. The microscope is a flexible platform accommodating various conditions, from low vacuum (10(-2) Pa) to helium gas filled ambient pressure. This flexibility greatly expands the application area, from in situ materials science to biology systems in their native state, by significantly relaxing restrictions to the sample environment. The coherent diffraction microscope has been used successfully to image a yeast cell immersed in buffer solution. We believe that the design of this coherent diffraction microscope can be directly adapted to various platforms such as table top soft x-ray laser, synchrotron x-ray sources, and x-ray free electron laser with minor relevant adjustments.

Development of an adaptable coherent x-ray diffraction microscope with the emphasis on imaging hydrated specimens

NASA Astrophysics Data System (ADS)

Nam, Daewoong; Park, Jaehyun; Gallagher-Jones, Marcus; Shimada, Hiroki; Kim, Sangsoo; Kim, Sunam; Kohmura, Yoshiki; Ishikawa, Tetsuya; Song, Changyong

2013-11-01

This paper describes the development of a versatile coherent x-ray diffraction microscope capable of imaging biological specimens in solution. The microscope is a flexible platform accommodating various conditions, from low vacuum (10-2 Pa) to helium gas filled ambient pressure. This flexibility greatly expands the application area, from in situ materials science to biology systems in their native state, by significantly relaxing restrictions to the sample environment. The coherent diffraction microscope has been used successfully to image a yeast cell immersed in buffer solution. We believe that the design of this coherent diffraction microscope can be directly adapted to various platforms such as table top soft x-ray laser, synchrotron x-ray sources, and x-ray free electron laser with minor relevant adjustments.

Thin Film Research. Volume 1

DTIC Science & Technology

1985-05-30

Order (FECO) ......... 23 3. X -Ray Diffraction ............................... 26 4. Transmission Electron Microscopy (TEM) ............... 26 5...remained amorphous after bombardment, as evidenced by X - ray diffraction, and showed no other changes. 0 (2) For Sb203, the crystallite size was reduced...main effect on MgF2 was the reduction in crystallite size. The films were too thir. for meaningful x - ray diffraction analysis. Durability and

X-Ray Diffraction and the Discovery of the Structure of DNA

ERIC Educational Resources Information Center

Crouse, David T.

2007-01-01

A method is described for teaching the analysis of X-ray diffraction of DNA through a series of steps utilizing the original methods used by James Watson, Francis Crick, Maurice Wilkins and Rosalind Franklin. The X-ray diffraction pattern led to the conclusion of the basic helical structure of DNA and its dimensions while basic chemical principles…

High Resolution X-Ray Diffraction of Macromolecules with Synchrotron Radiation

NASA Technical Reports Server (NTRS)

Stojanoff, Vivian; Boggon, Titus; Helliwell, John R.; Judge, Russell; Olczak, Alex; Snell, Edward H.; Siddons, D. Peter; Rose, M. Franklin (Technical Monitor)

2000-01-01

We recently combined synchrotron-based monochromatic X-ray diffraction topography methods with triple axis diffractometry and rocking curve measurements: high resolution X-ray diffraction imaging techniques, to better understand the quality of protein crystals. We discuss these methods in the light of results obtained on crystals grown under different conditions. These non destructive techniques are powerful tools in the characterization of the protein crystals and ultimately will allow to improve, develop, and understand protein crystal growth. High resolution X-ray diffraction imaging methods will be discussed in detail in light of recent results obtained on Hen Egg White Lysozyme crystals and other proteins.

Hard X-ray polarizer to enable simultaneous three-dimensional nanoscale imaging of magnetic structure and lattice strain

DOE PAGES

Logan, Jonathan; Harder, Ross; Li, Luxi; ...

2016-01-01

Recent progress in the development of dichroic Bragg coherent diffractive imaging, a new technique for simultaneous three-dimensional imaging of strain and magnetization at the nanoscale, is reported. This progress includes the installation of a diamond X-ray phase retarder at beamline 34-ID-C of the Advanced Photon Source. Here, the performance of the phase retarder for tuning X-ray polarization is demonstrated with temperature-dependent X-ray magnetic circular dichroism measurements on a gadolinium foil in transmission and on a Gd 5Si 2Ge 2crystal in diffraction geometry with a partially coherent, focused X-ray beam. Feasibility tests for dichroic Bragg coherent diffractive imaging are presented. Thesemore » tests include (1) using conventional Bragg coherent diffractive imaging to determine whether the phase retarder introduces aberrations using a nonmagnetic gold nanocrystal as a control sample, and (2) collecting coherent diffraction patterns of a magnetic Gd 5Si 2Ge 2nanocrystal with left- and right-circularly polarized X-rays. Future applications of dichroic Bragg coherent diffractive imaging for the correlation of strain and lattice defects with magnetic ordering and inhomogeneities are considered.« less

Synthesis, structure and temperature dependent luminescence of Eu3+ doped hydroxyapatite

NASA Astrophysics Data System (ADS)

Luo, Xiaobing; Luo, Xiaoxia; Wang, Hongwei; Deng, Yue; Yang, Peixin; Tian, Yili

2018-01-01

A series of Eu3+ substituted hydroxyapatite (HA) were prepared by co-precipitation reactions. The phase, fluorescence and temperature dependent luminescence of the phosphors were investigated by X-ray diffraction (XRD) and photoluminescence (PL). It is found that the doped Eu3+ ions have entered the hexagonal lattice with no obvious secondary phase were detected by XRD. The 5D0 → 7F0 transition was clearly split into two even at room temperature. The predominate 573 nm peak illustrates Eu3+ ions occupy more Ca(II) sites. The temperature dependent luminescent results show HA:xEu might be applied as one potential optical thermometry material.

High Capacity of Hard Carbon Anode in Na-Ion Batteries Unlocked by PO x Doping

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

Li, Zhifei; Ma, Lu; Surta, Todd Wesley

2016-08-12

The capacity of hard carbon anodes in Na-ion batteries 2.5 rarely reaches values beyond 300 mAh/g. We report that doping POx into local structures of hard carbon increases its reversible capacity from 283 to 359 mAh/g. We confirm that the doped POx is redox inactive by X-ray adsorption near edge structure measurements, thus not contributing to the higher capacity. We observe two significant changes of hard carbon's local structures caused by doping. First, the (002) d-spacing inside the turbostratic nanodomains is increased, revealed by both laboratory and synchrotron X-ray diffraction. Second, doping turns turbostratic nanodomains more defective along ab planes,more » indicated by neutron total scattering and the associated pair distribution function studies. The local structural changes of hard carbon are correlated to the higher capacity, where both the plateau and slope regions in the potential profiles are enhanced. Our study demonstrates that Na-ion storage in hard carbon heavily depends on carbon local structures, where such structures, despite being disordered, can be tuned toward unusually high capacities.« less

Three Dimensional Variable-Wavelength X-Ray Bragg Coherent Diffraction Imaging

DOE PAGES

Cha, W.; Ulvestad, A.; Allain, M.; ...

2016-11-23

Here, we present and demonstrate a formalism by which three-dimensional (3D) Bragg x-ray coherent diffraction imaging (BCDI) can be implemented without moving the sample by scanning the energy of the incident x-ray beam. This capability is made possible by introducing a 3D Fourier transform that accounts for x-ray wavelength variability. We also demonstrate the approach by inverting coherent Bragg diffraction patterns from a gold nanocrystal measured with an x-ray energy scan. Furthermore, variable-wavelength BCDI will expand the breadth of feasible in situ 3D strain imaging experiments towards more diverse materials environments, especially where sample manipulation is difficult.

Synchrotron X-Ray Diffraction Analysis of Meteorites in Thin Section: Preliminary Results

NASA Technical Reports Server (NTRS)

Treiman, A. H.; Lanzirotti, A.; Xirouchakis, D.

2004-01-01

X-ray diffraction is the pre-eminent technique for mineral identification and structure determination, but is difficult to apply to grains in thin section, the standard meteorite preparation. Bright focused X-ray beams from synchrotrons have been used extensively in mineralogy and have been applied to extraterrestrial particles. The intensity and small spot size achievable in synchrotron X-ray beams makes them useful for study of materials in thin sections. Here, we describe Synchrotron X-ray Diffraction (SXRD) in thin section as done at the National Synchrotron Light Source, and cite examples of its value for studies of meteorites in thin section.

Three Dimensional Variable-Wavelength X-Ray Bragg Coherent Diffraction Imaging

NASA Astrophysics Data System (ADS)

Cha, W.; Ulvestad, A.; Allain, M.; Chamard, V.; Harder, R.; Leake, S. J.; Maser, J.; Fuoss, P. H.; Hruszkewycz, S. O.

2016-11-01

We present and demonstrate a formalism by which three-dimensional (3D) Bragg x-ray coherent diffraction imaging (BCDI) can be implemented without moving the sample by scanning the energy of the incident x-ray beam. This capability is made possible by introducing a 3D Fourier transform that accounts for x-ray wavelength variability. We demonstrate the approach by inverting coherent Bragg diffraction patterns from a gold nanocrystal measured with an x-ray energy scan. Variable-wavelength BCDI will expand the breadth of feasible in situ 3D strain imaging experiments towards more diverse materials environments, especially where sample manipulation is difficult.

Three Dimensional Variable-Wavelength X-Ray Bragg Coherent Diffraction Imaging.

PubMed

Cha, W; Ulvestad, A; Allain, M; Chamard, V; Harder, R; Leake, S J; Maser, J; Fuoss, P H; Hruszkewycz, S O

2016-11-25

We present and demonstrate a formalism by which three-dimensional (3D) Bragg x-ray coherent diffraction imaging (BCDI) can be implemented without moving the sample by scanning the energy of the incident x-ray beam. This capability is made possible by introducing a 3D Fourier transform that accounts for x-ray wavelength variability. We demonstrate the approach by inverting coherent Bragg diffraction patterns from a gold nanocrystal measured with an x-ray energy scan. Variable-wavelength BCDI will expand the breadth of feasible in situ 3D strain imaging experiments towards more diverse materials environments, especially where sample manipulation is difficult.

In-situ X-ray diffraction system using sources and detectors at fixed angular positions

DOEpatents

Gibson, David M [Voorheesville, NY; Gibson, Walter M [Voorheesville, NY; Huang, Huapeng [Latham, NY

2007-06-26

An x-ray diffraction technique for measuring a known characteristic of a sample of a material in an in-situ state. The technique includes using an x-ray source for emitting substantially divergent x-ray radiation--with a collimating optic disposed with respect to the fixed source for producing a substantially parallel beam of x-ray radiation by receiving and redirecting the divergent paths of the divergent x-ray radiation. A first x-ray detector collects radiation diffracted from the sample; wherein the source and detector are fixed, during operation thereof, in position relative to each other and in at least one dimension relative to the sample according to a-priori knowledge about the known characteristic of the sample. A second x-ray detector may be fixed relative to the first x-ray detector according to the a-priori knowledge about the known characteristic of the sample, especially in a phase monitoring embodiment of the present invention.

Facile one-pot synthesis of hexagons of NaSrB5O9:Tb3+ phosphor for solid-state lighting

NASA Astrophysics Data System (ADS)

Ramesh, B.; Dillip, G. R.; Deva Prasad Raju, B.; Somasundaram, K.; Prasad Peddi, Siva; de Carvalho dos Anjos, Virgilio; Joo, S. W.

2017-04-01

NaSrB5O9:Tb3+ hexagons were synthesized by a facile solid-state reaction method. The synthesized powders were structurally examined by x-ray diffraction analysis (XRD), and Rietveld refinement was performed using the XRD data and Fullprof software. Hexagon-like morphology was observed using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The elemental composition of the phosphors was investigated qualitatively by energy dispersive x-ray analysis (EDS) and quantitatively by x-ray photoelectron spectroscopy (XPS). The phosphor has a strong green emission at 545 nm under excitation of 379 nm, which is due to the 5{{\\text{D}}4}{{\\to}7}{{\\text{F}}5} transition of the Tb3+ ion. A lifetime of 3.48 ms was obtained for the phosphor. The important parameters of the light source were determined, such as the thermal quenching, critical distance, the nature of the dopant ion interaction, color coordinates, and quantum yield values. Other reported properties include the site occupancy of the dopant, surface properties, morphological properties, and optical properties.

Novel Bi/BiOBr/AgBr composite microspheres: Ion exchange synthesis and photocatalytic performance

NASA Astrophysics Data System (ADS)

Lyu, Jianchang; Li, Zhenlu; Ge, Ming

2018-06-01

Novel Bi/BiOBr/AgBr composite microspheres were prepared by a rational in situ ion exchange reaction between Bi/BiOBr microspheres and AgNO3. The characteristic of the as-obtained ternary microspheres was tested by X-ray diffraction (XRD), energy dispersive X-ray spectrometer (EDS), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (UV-vis DRS) and photoluminescence (PL). Under visible light irradiation, Bi/BiOBr/AgBr microspheres exhibited an excellent photocatalytic efficiency for rhodamine B (RhB) degradation, which was about 1.4 and 4.9 times as high as that of Bi/BiOBr and BiOBr/AgBr, demonstrating that the highest separation efficiency of charge carriers in the heterostructured Bi/BiOBr/AgBr. The photocatalytic activity of Bi/BiOBr/AgBr microspheres just exhibited a slight decrease after three consecutive cycles. The photocatalytic mechanism investigation confirmed that the superoxide radicals (O2•-) were the dominant reactive oxygen species for RhB degradation in Bi/BiOBr/AgBr suspension.

The use of analytical surface tools in the fundamental study of wear. [atomic nature of wear

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1977-01-01

Various techniques and surface tools available for the study of the atomic nature of the wear of materials are reviewed These include chemical etching, x-ray diffraction, electron diffraction, scanning electron microscopy, low-energy electron diffraction, Auger emission spectroscopy analysis, electron spectroscopy for chemical analysis, field ion microscopy, and the atom probe. Properties of the surface and wear surface regions which affect wear, such as surface energy, crystal structure, crystallographic orientation, mode of dislocation behavior, and cohesive binding, are discussed. A number of mechanisms involved in the generation of wear particles are identified with the aid of the aforementioned tools.

Swift heavy ion induced topography changes of Tin oxide thin films

NASA Astrophysics Data System (ADS)

Jaiswal, Manoj K.; Kumar, Avesh; Kanjilal, D.; Mohanty, T.

2012-12-01

Monodisperse tin oxide nanocrystalline thin films are grown on silicon substrates by electron beam evaporation method followed by 100 MeV silver ion bombardment with varying ion fluence from 5 × 1011 ions cm-2 to 1 × 1013 ions cm-2 at constant ion flux. Enhancement of crystallinity of thin films with fluence is observed from glancing angle X-ray diffraction studies. Morphological studies by atomic force microscopy reveal the changes in grain size from 25 nm to 44 nm with variation in ion fluence. The effect of initial surface roughness and adatom mobility on topography is reported. In this work correlation between ion beam induced defect concentration with topography and grain size distribution is emphasized.

Synthesis, characterization and lithium-ion migration dynamics simulation of LiFe1- x T x PO4 (T = Mn, Co, La and Ce) doping cathode material for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Xiao, Yi; Zhang, Fu Chun; Han, Jeong In

2016-11-01

LiFePO4 was doped by metallic cation in Fe sites via ball milling by a solid-state reaction method synthesis, and with very low-level doping of these samples, such as Li0.95T0.05FePO4 (where T = Mn2+, Co2+, La3+, Ce4+). The effects of doping were studied by X-ray diffraction pattern, Raman shift, scanning electronic microscopy and energy-dispersive X-ray spectroscopy as sample characterizations. The results indicate that these dopants have no significant effect on the structure of the material, but considerably improve its electrochemical behavior. First-principles calculations were used to obtain the migration pathway of Li ions along the one-dimensional (010) direction in LiFePO4, and molecular dynamics simulation was used to investigate the lithium-ion diffusion coefficients ( D Li) inside LiFePO4, which were derived from the slope of the mean square displacement versus time plots. The evolution of the structure during the simulation was analyzed by the radial distribution function to obtain the data, and radial distribution functions and mean square displacements were used to confirm the formation of crystalline units and the evolution of structure.

The effect of exit beam phase aberrations on parallel beam coherent x-ray reconstructions

NASA Astrophysics Data System (ADS)

Hruszkewycz, S. O.; Harder, R.; Xiao, X.; Fuoss, P. H.

2010-12-01

Diffraction artifacts from imperfect x-ray windows near the sample are an important consideration in the design of coherent x-ray diffraction measurements. In this study, we used simulated and experimental diffraction patterns in two and three dimensions to explore the effect of phase imperfections in a beryllium window (such as a void or inclusion) on the convergence behavior of phasing algorithms and on the ultimate reconstruction. A predictive relationship between beam wavelength, sample size, and window position was derived to explain the dependence of reconstruction quality on beryllium defect size. Defects corresponding to this prediction cause the most damage to the sample exit wave and induce signature error oscillations during phasing that can be used as a fingerprint of experimental x-ray window artifacts. The relationship between x-ray window imperfection size and coherent x-ray diffractive imaging reconstruction quality explored in this work can play an important role in designing high-resolution in situ coherent imaging instrumentation and will help interpret the phasing behavior of coherent diffraction measured in these in situ environments.

The effect of exit beam phase aberrations on parallel beam coherent x-ray reconstructions.

PubMed

Hruszkewycz, S O; Harder, R; Xiao, X; Fuoss, P H

2010-12-01

Diffraction artifacts from imperfect x-ray windows near the sample are an important consideration in the design of coherent x-ray diffraction measurements. In this study, we used simulated and experimental diffraction patterns in two and three dimensions to explore the effect of phase imperfections in a beryllium window (such as a void or inclusion) on the convergence behavior of phasing algorithms and on the ultimate reconstruction. A predictive relationship between beam wavelength, sample size, and window position was derived to explain the dependence of reconstruction quality on beryllium defect size. Defects corresponding to this prediction cause the most damage to the sample exit wave and induce signature error oscillations during phasing that can be used as a fingerprint of experimental x-ray window artifacts. The relationship between x-ray window imperfection size and coherent x-ray diffractive imaging reconstruction quality explored in this work can play an important role in designing high-resolution in situ coherent imaging instrumentation and will help interpret the phasing behavior of coherent diffraction measured in these in situ environments.

Femtosecond X-ray Diffraction From Two-Dimensional Protein Crystals

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

Frank, Matthias; Carlson, David B.; Hunter, Mark

2014-02-28

Here we present femtosecond x-ray diffraction patterns from two-dimensional (2-D) protein crystals using an x-ray free electron laser (XFEL). To date it has not been possible to acquire x-ray diffraction from individual 2-D protein crystals due to radiation damage. However, the intense and ultrafast pulses generated by an XFEL permits a new method of collecting diffraction data before the sample is destroyed. Utilizing a diffract-before-destroy methodology at the Linac Coherent Light Source, we observed Bragg diffraction to better than 8.5 Å resolution for two different 2-D protein crystal samples that were maintained at room temperature. These proof-of-principle results show promisemore » for structural analysis of both soluble and membrane proteins arranged as 2-D crystals without requiring cryogenic conditions or the formation of three-dimensional crystals.« less

Influence of gamma ray irradiation on stoichiometry of hydrothermally synthesized bismuth telluride nanoparticles

NASA Astrophysics Data System (ADS)

Abishek, N. S.; Naik, K. Gopalakrishna

2018-05-01

Bismuth telluride (Bi2Te3) nanoparticles were synthesized by the hydrothermal method at 200 °C for 24 h. The synthesized Bi2Te3 nanoparticles were irradiated with gamma rays at doses of 50 kGy and 100 kGy. The structural characterization of the pre-irradiated and post-irradiated samples was carried out by X-ray diffraction technique and was found to have rhombohedral phase having R3 ¯m (166) space group. The X-ray diffraction peaks were found to shift towards lower diffraction angle with gamma ray irradiation. The morphologies and compositions of the grown Bi2Te3 nanoparticles were studied using Field Emission Scanning Electron Microscope and X-ray energy dispersive analysis, respectively. The possible cause for the shift in the X-ray diffraction peaks with gamma ray irradiation has been discussed in the present work.

High Power Optical Coatings by Atomic Layer Deposition and Signatures of Laser-Induced Damage

DTIC Science & Technology

2012-08-28

diffraction angle 0 into crystal lattice spacing d by the Bragg condition, mX = 2d sin 0. Here X is the x - ray wavelength... angle x - ray diffraction (GAXRD) measurements, which were made at a fixed shallow incidence angle of 0.5°. Detector scans were done to measure the...was finished with 200 hafnia cycles m the fmal half period rather than 400. Crystallinity was measured by x - ray diffraction (XRD) with

Effect of replacing Sn4+ ions by Zn2+ ions on structural, optical and magnetic properties of SnO2 nanoparticles

NASA Astrophysics Data System (ADS)

Selvi, E. Thamarai; Sundar, S. Meenakshi

2017-05-01

This paper highlights on the consequence of replacing tetravalent Sn4+ ions of the SnO2 by divalent Zn2+ ions on their structural, optical, and magnetic properties. Samples of Sn1- x Zn x O2 with x = 0, 0.01, 0.02, 0.03, and 0.04 were synthesized using microwave irradiated solvothermal process. The X-ray powder diffraction patterns reveal the rutile tetragonal phase of all doped SnO2 samples with no secondary phases. The transmission electron microscopy results show the formation of spherical nanoparticles of size 10-30 nm. Morphological changes were observed by scanning electron microscopy. The functional groups were investigated using Fourier transform infrared spectroscopy studies. Optical studies were carried by UV-Vis spectroscopy and fluorescence spectroscopy. Electron paramagnetic resonance was used to calculate the Lande splitting factor ` g'. The magnetic properties using vibrating sample magnetometer exhibit room temperature ferromagnetism for all the samples.

Instrument and method for focusing X-rays, gamma rays and neutrons

DOEpatents

Smither, Robert K.

1984-01-01

A crystal diffraction instrument or diffraction grating instrument with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the crystalline structure, by assembling a plurality of crystalline structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal diffraction case.

Instrument and method for focusing x rays, gamma rays, and neutrons

DOEpatents

Smither, R.K.

1982-03-25

A crystal-diffraction instrument or diffraction-grating instrument is described with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the line structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam, or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal-diffraction case.

Materials identification using a small-scale pixellated x-ray diffraction system

NASA Astrophysics Data System (ADS)

O'Flynn, D.; Crews, C.; Drakos, I.; Christodoulou, C.; Wilson, M. D.; Veale, M. C.; Seller, P.; Speller, R. D.

2016-05-01

A transmission x-ray diffraction system has been developed using a pixellated, energy-resolving detector (HEXITEC) and a small-scale, mains operated x-ray source (Amptek Mini-X). HEXITEC enables diffraction to be measured without the requirement of incident spectrum filtration, or collimation of the scatter from the sample, preserving a large proportion of the useful signal compared with other diffraction techniques. Due to this efficiency, sufficient molecular information for material identification can be obtained within 5 s despite the relatively low x-ray source power. Diffraction data are presented from caffeine, hexamine, paracetamol, plastic explosives and narcotics. The capability to determine molecular information from aspirin tablets inside their packaging is demonstrated. Material selectivity and the potential for a sample classification model is shown with principal component analysis, through which each different material can be clearly resolved.

X-ray diffraction study of Penicillium Vitale catalase in the complex with aminotriazole

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

Borovik, A. A.; Grebenko, A. I.; Melik-Adamyan, V. R., E-mail: mawr@ns.crys.ras.ru

2011-07-15

The three-dimensional structure of the enzyme catalase from Penicillium vitale in a complex with the inhibitor aminotriazole was solved and refined by protein X-ray crystallography methods. An analysis of the three-dimensional structure of the complex showed that the inhibition of the enzyme occurs as a result of the covalent binding of aminotriazole to the amino-acid residue His64 in the active site of the enzyme. An investigation of the three-dimensional structure of the complex resulted in the amino-acid residues being more precisely identified. The binding sites of saccharide residues and calcium ions in the protein molecule were found.

Dynamic X-ray diffraction sampling for protein crystal positioning

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

Scarborough, Nicole M.; Godaliyadda, G. M. Dilshan P.; Ye, Dong Hye

A sparse supervised learning approach for dynamic sampling (SLADS) is described for dose reduction in diffraction-based protein crystal positioning. Crystal centering is typically a prerequisite for macromolecular diffraction at synchrotron facilities, with X-ray diffraction mapping growing in popularity as a mechanism for localization. In X-ray raster scanning, diffraction is used to identify the crystal positions based on the detection of Bragg-like peaks in the scattering patterns; however, this additional X-ray exposure may result in detectable damage to the crystal prior to data collection. Dynamic sampling, in which preceding measurements inform the next most information-rich location to probe for image reconstruction,more » significantly reduced the X-ray dose experienced by protein crystals during positioning by diffraction raster scanning. The SLADS algorithm implemented herein is designed for single-pixel measurements and can select a new location to measure. In each step of SLADS, the algorithm selects the pixel, which, when measured, maximizes the expected reduction in distortion given previous measurements. Ground-truth diffraction data were obtained for a 5 µm-diameter beam and SLADS reconstructed the image sampling 31% of the total volume and only 9% of the interior of the crystal greatly reducing the X-ray dosage on the crystal. Furthermore, by usingin situtwo-photon-excited fluorescence microscopy measurements as a surrogate for diffraction imaging with a 1 µm-diameter beam, the SLADS algorithm enabled image reconstruction from a 7% sampling of the total volume and 12% sampling of the interior of the crystal. When implemented into the beamline at Argonne National Laboratory, without ground-truth images, an acceptable reconstruction was obtained with 3% of the image sampled and approximately 5% of the crystal. The incorporation of SLADS into X-ray diffraction acquisitions has the potential to significantly minimize the impact of X-ray exposure on the crystal by limiting the dose and area exposed for image reconstruction and crystal positioning using data collection hardware present in most macromolecular crystallography end-stations.« less

Dynamic X-ray diffraction sampling for protein crystal positioning

DOE PAGES

Scarborough, Nicole M.; Godaliyadda, G. M. Dilshan P.; Ye, Dong Hye; ...

2017-01-01

A sparse supervised learning approach for dynamic sampling (SLADS) is described for dose reduction in diffraction-based protein crystal positioning. Crystal centering is typically a prerequisite for macromolecular diffraction at synchrotron facilities, with X-ray diffraction mapping growing in popularity as a mechanism for localization. In X-ray raster scanning, diffraction is used to identify the crystal positions based on the detection of Bragg-like peaks in the scattering patterns; however, this additional X-ray exposure may result in detectable damage to the crystal prior to data collection. Dynamic sampling, in which preceding measurements inform the next most information-rich location to probe for image reconstruction,more » significantly reduced the X-ray dose experienced by protein crystals during positioning by diffraction raster scanning. The SLADS algorithm implemented herein is designed for single-pixel measurements and can select a new location to measure. In each step of SLADS, the algorithm selects the pixel, which, when measured, maximizes the expected reduction in distortion given previous measurements. Ground-truth diffraction data were obtained for a 5 µm-diameter beam and SLADS reconstructed the image sampling 31% of the total volume and only 9% of the interior of the crystal greatly reducing the X-ray dosage on the crystal. Furthermore, by usingin situtwo-photon-excited fluorescence microscopy measurements as a surrogate for diffraction imaging with a 1 µm-diameter beam, the SLADS algorithm enabled image reconstruction from a 7% sampling of the total volume and 12% sampling of the interior of the crystal. When implemented into the beamline at Argonne National Laboratory, without ground-truth images, an acceptable reconstruction was obtained with 3% of the image sampled and approximately 5% of the crystal. The incorporation of SLADS into X-ray diffraction acquisitions has the potential to significantly minimize the impact of X-ray exposure on the crystal by limiting the dose and area exposed for image reconstruction and crystal positioning using data collection hardware present in most macromolecular crystallography end-stations.« less

Dynamic X-ray diffraction sampling for protein crystal positioning

PubMed Central

Scarborough, Nicole M.; Godaliyadda, G. M. Dilshan P.; Ye, Dong Hye; Kissick, David J.; Zhang, Shijie; Newman, Justin A.; Sheedlo, Michael J.; Chowdhury, Azhad U.; Fischetti, Robert F.; Das, Chittaranjan; Buzzard, Gregery T.; Bouman, Charles A.; Simpson, Garth J.

2017-01-01

A sparse supervised learning approach for dynamic sampling (SLADS) is described for dose reduction in diffraction-based protein crystal positioning. Crystal centering is typically a prerequisite for macromolecular diffraction at synchrotron facilities, with X-ray diffraction mapping growing in popularity as a mechanism for localization. In X-ray raster scanning, diffraction is used to identify the crystal positions based on the detection of Bragg-like peaks in the scattering patterns; however, this additional X-ray exposure may result in detectable damage to the crystal prior to data collection. Dynamic sampling, in which preceding measurements inform the next most information-rich location to probe for image reconstruction, significantly reduced the X-ray dose experienced by protein crystals during positioning by diffraction raster scanning. The SLADS algorithm implemented herein is designed for single-pixel measurements and can select a new location to measure. In each step of SLADS, the algorithm selects the pixel, which, when measured, maximizes the expected reduction in distortion given previous measurements. Ground-truth diffraction data were obtained for a 5 µm-diameter beam and SLADS reconstructed the image sampling 31% of the total volume and only 9% of the interior of the crystal greatly reducing the X-ray dosage on the crystal. Using in situ two-photon-excited fluorescence microscopy measurements as a surrogate for diffraction imaging with a 1 µm-diameter beam, the SLADS algorithm enabled image reconstruction from a 7% sampling of the total volume and 12% sampling of the interior of the crystal. When implemented into the beamline at Argonne National Laboratory, without ground-truth images, an acceptable reconstruction was obtained with 3% of the image sampled and approximately 5% of the crystal. The incorporation of SLADS into X-ray diffraction acquisitions has the potential to significantly minimize the impact of X-ray exposure on the crystal by limiting the dose and area exposed for image reconstruction and crystal positioning using data collection hardware present in most macromolecular crystallography end-stations. PMID:28009558

Dynamic X-ray diffraction sampling for protein crystal positioning.

PubMed

Scarborough, Nicole M; Godaliyadda, G M Dilshan P; Ye, Dong Hye; Kissick, David J; Zhang, Shijie; Newman, Justin A; Sheedlo, Michael J; Chowdhury, Azhad U; Fischetti, Robert F; Das, Chittaranjan; Buzzard, Gregery T; Bouman, Charles A; Simpson, Garth J

2017-01-01

A sparse supervised learning approach for dynamic sampling (SLADS) is described for dose reduction in diffraction-based protein crystal positioning. Crystal centering is typically a prerequisite for macromolecular diffraction at synchrotron facilities, with X-ray diffraction mapping growing in popularity as a mechanism for localization. In X-ray raster scanning, diffraction is used to identify the crystal positions based on the detection of Bragg-like peaks in the scattering patterns; however, this additional X-ray exposure may result in detectable damage to the crystal prior to data collection. Dynamic sampling, in which preceding measurements inform the next most information-rich location to probe for image reconstruction, significantly reduced the X-ray dose experienced by protein crystals during positioning by diffraction raster scanning. The SLADS algorithm implemented herein is designed for single-pixel measurements and can select a new location to measure. In each step of SLADS, the algorithm selects the pixel, which, when measured, maximizes the expected reduction in distortion given previous measurements. Ground-truth diffraction data were obtained for a 5 µm-diameter beam and SLADS reconstructed the image sampling 31% of the total volume and only 9% of the interior of the crystal greatly reducing the X-ray dosage on the crystal. Using in situ two-photon-excited fluorescence microscopy measurements as a surrogate for diffraction imaging with a 1 µm-diameter beam, the SLADS algorithm enabled image reconstruction from a 7% sampling of the total volume and 12% sampling of the interior of the crystal. When implemented into the beamline at Argonne National Laboratory, without ground-truth images, an acceptable reconstruction was obtained with 3% of the image sampled and approximately 5% of the crystal. The incorporation of SLADS into X-ray diffraction acquisitions has the potential to significantly minimize the impact of X-ray exposure on the crystal by limiting the dose and area exposed for image reconstruction and crystal positioning using data collection hardware present in most macromolecular crystallography end-stations.

Transmission electron microscope studies of extraterrestrial materials

NASA Technical Reports Server (NTRS)

Keller, Lindsay P.

1995-01-01

Transmission Electron Microscopy, X-Ray spectrometry and electron-energy-loss spectroscopy are used to analyse carbon in interplanetary dust particles. Optical micrographs are shown depicting cross sections of the dust particles embedded in sulphur. Selected-area electron diffraction patterns are shown. Transmission Electron Microscope specimens of lunar soil were prepared using two methods: ion-milling and ultramicrotomy. A combination of high resolution TEM imaging and electron diffraction is used to characterize the opaque assemblages. The opaque assemblages analyzed in this study are dominated by ilmenite with lesser rutile and spinel exsolutions, and traces of Fe metal.

Luminescence and Scintillation Properties of Czochralski Grown LYGBO Crystals

NASA Astrophysics Data System (ADS)

Fawad, U.; Kim, Hong Joo; Park, H.; Kim, Sunghwan; Khan, Sajid

2016-06-01

Mixed crystals Li6YxGd1-x(BO3)3:Ce3+ (LYGBO) (where, x = 0.0, 0.2, 0.5, 0.8, 1.0) are grown by using Czochralski method with different proportions of Li6Y(BO3)3 and Li6Gd(BO3)3. All crystals are doped with 3 mole% optimized concentrations of Ce3+ ions. The grown crystals are 20-70 mm in length and 5-10 mm in diameter. Detailed sintering and crystal growth procedure is presented in this study. The required phase of the grown crystals is confirmed by powder X-ray diffraction (XRD) analysis. Ultraviolet (UV) photoluminescence and X-ray induced luminescence of the grown crystals at room temperature are measured. Various scintillation properties such as energy resolution, light yield, α/β ratio and fluorescence decay time under the excitation by 137Cs γ-ray and 241Am particles are also presented.

ZnS Buffer Layers Grown by Modified Chemical Bath Deposition for CIGS Solar Cells

NASA Astrophysics Data System (ADS)

Lee, Dongchan; Ahn, Heejin; Shin, Hyundo; Um, Youngho

2018-03-01

ZnS thin films were prepared by the chemical bath deposition method using disodium ethylene-diaminetetraacetic acid and hexamethylenetetramine as complexing agents in acidic conditions. The film prepared using a preheated S-ion source showed full surface coverage, but some clusters were found that were generated by the cluster-by-cluster reaction mechanism. On the other hand, the film prepared without this source had a uniform, dense, and smooth surface and showed fewer clusters than the film prepared using a preheated S-ion source. The x-ray photoelectron spectroscopy spectra showed the energy core levels of Zn, O, and S components, and Zn-OH bonding decreased on the film using the preheated S-ion source. Especially, various binding energy peaks were found in the Zn 2p 3/2 spectrum by Gaussian function fitting, and no peak corresponding to Zn-OH bonding was found for the film prepared using a preheated S-ion source. Moreover, the x-ray diffraction spectrum of the ZnS thin film using a non-preheated S-ion source showed amorphous or nanoscale crystallinity, but the emission peaks indicated that the structure of the film using preheated S-ion source was zincblende.

ZnS Buffer Layers Grown by Modified Chemical Bath Deposition for CIGS Solar Cells

NASA Astrophysics Data System (ADS)

Lee, Dongchan; Ahn, Heejin; Shin, Hyundo; Um, Youngho

2018-07-01

ZnS thin films were prepared by the chemical bath deposition method using disodium ethylene-diaminetetraacetic acid and hexamethylenetetramine as complexing agents in acidic conditions. The film prepared using a preheated S-ion source showed full surface coverage, but some clusters were found that were generated by the cluster-by-cluster reaction mechanism. On the other hand, the film prepared without this source had a uniform, dense, and smooth surface and showed fewer clusters than the film prepared using a preheated S-ion source. The x-ray photoelectron spectroscopy spectra showed the energy core levels of Zn, O, and S components, and Zn-OH bonding decreased on the film using the preheated S-ion source. Especially, various binding energy peaks were found in the Zn 2 p 3/2 spectrum by Gaussian function fitting, and no peak corresponding to Zn-OH bonding was found for the film prepared using a preheated S-ion source. Moreover, the x-ray diffraction spectrum of the ZnS thin film using a non-preheated S-ion source showed amorphous or nanoscale crystallinity, but the emission peaks indicated that the structure of the film using preheated S-ion source was zincblende.

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

Arul, K. Thanigai; Kolanthai, Elayaraja; Manikandan, E.

Highlights: • Rapid technique to synthesize nanorods of magnesium ion incorporated hydroxyapatite. • Enhanced electrical and mechanical properties. • Improved photoluminescence and wettability on magnesium incorporation. • Increased in vitro bioactivity. - Abstract: Nanocrystalline hydroxyapatite (HAp-Ca{sub 10}(PO{sub 4}){sub 6}(OH){sub 2,} 35 nm) and magnesium (Mg{sup 2+}) ion incorporated HAp were synthesized by microwave technique. XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy), FE-HRTEM (Field emission high resolution transmission electron microscopy), DLS (dynamic light scattering), EDXRF (energy dispersive X-ray fluorescence spectrometry), microhardness, permittivity and alternating current (ac) conductivity, besides the PL (photoluminescence), wettability and in vitro bioactivity of the samples weremore » analysed. EDXRF revealed the Mg{sup 2+} ion incorporation in HAp. The Mg{sup 2+} ion incorporation did not alter the phase but drastically reduced the crystallite size and particle size respectively by 48% and 32%. There was enhanced microhardness (24%) at low level (<13%) and decreased zeta potential of Mg{sup 2+} ion incorporation. The permittivity, ac conductivity, PL, wettability and in vitro bioactivity were enhanced on Mg{sup 2+} ion incorporation. These properties enable them to be a promising candidate for wound healing, bone replacement applications and also as a biosensor.« less

Nanostructured Black Phosphorus/Ketjenblack-Multiwalled Carbon Nanotubes Composite as High Performance Anode Material for Sodium-Ion Batteries.

PubMed

Xu, Gui-Liang; Chen, Zonghai; Zhong, Gui-Ming; Liu, Yuzi; Yang, Yong; Ma, Tianyuan; Ren, Yang; Zuo, Xiaobing; Wu, Xue-Hang; Zhang, Xiaoyi; Amine, Khalil

2016-06-08

Sodium-ion batteries are promising alternatives to lithium-ion batteries for large-scale applications. However, the low capacity and poor rate capability of existing anodes for sodium-ion batteries are bottlenecks for future developments. Here, we report a high performance nanostructured anode material for sodium-ion batteries that is fabricated by high energy ball milling to form black phosphorus/Ketjenblack-multiwalled carbon nanotubes (BPC) composite. With this strategy, the BPC composite with a high phosphorus content (70 wt %) could deliver a very high initial Coulombic efficiency (>90%) and high specific capacity with excellent cyclability at high rate of charge/discharge (∼1700 mAh g(-1) after 100 cycles at 1.3 A g(-1) based on the mass of P). In situ electrochemical impedance spectroscopy, synchrotron high energy X-ray diffraction, ex situ small/wide-angle X-ray scattering, high resolution transmission electronic microscopy, and nuclear magnetic resonance were further used to unravel its superior sodium storage performance. The scientific findings gained in this work are expected to serve as a guide for future design on high performance anode material for sodium-ion batteries.

Fixture for supporting and aligning a sample to be analyzed in an x-ray diffraction apparatus

DOEpatents

Green, L.A.; Heck, J.L. Jr.

1985-04-23

A fixture is provided for supporting and aligning small samples of material on a goniometer for x-ray diffraction analysis. A sample-containing capillary is accurately positioned for rotation in the x-ray beam by selectively adjusting the fixture to position the capillary relative to the x and y axes thereof to prevent wobble and position the sample along the z axis or the axis of rotation. By employing the subject fixture relatively small samples of materials can be analyzed in an x-ray diffraction apparatus previously limited to the analysis of much larger samples.

Fixture for supporting and aligning a sample to be analyzed in an X-ray diffraction apparatus

DOEpatents

Green, Lanny A.; Heck, Jr., Joaquim L.

1987-01-01

A fixture is provided for supporting and aligning small samples of material on a goniometer for X-ray diffraction analysis. A sample-containing capillary is accurately positioned for rotation in the X-ray beam by selectively adjusting the fixture to position the capillary relative to the x and y axes thereof to prevent wobble and position the sample along the z axis or the axis of rotation. By employing the subject fixture relatively small samples of materials can be analyzed in an X-ray diffraction apparatus previously limited to the analysis of much larger samples.

Ion density evolution in a high-power sputtering discharge with bipolar pulsing

NASA Astrophysics Data System (ADS)

Britun, N.; Michiels, M.; Godfroid, T.; Snyders, R.

2018-06-01

Time evolution of sputtered metal ions in high power impulse magnetron sputtering (HiPIMS) discharge with a positive voltage pulse applied after a negative one (regime called "bipolar pulse HiPIMS"—BPH) is studied using 2-D density mapping. It is demonstrated that the ion propagation dynamics is mainly affected by the amplitude and duration of the positive pulse. Such effects as ion repulsion from the cathode and the ionization zone shrinkage due to electron drift towards the cathode are clearly observed during the positive pulse. The BPH mode also alters the film crystallographic structure, as observed from X-ray diffraction analysis.

Local structure and oxide-ion conduction mechanism in apatite-type lanthanum silicates.

PubMed

Masson, Olivier; Berghout, Abid; Béchade, Emilie; Jouin, Jenny; Thomas, Philippe; Asaka, Toru; Fukuda, Koichiro

2017-01-01

The local structure of apatite-type lanthanum silicates of general formula La 9.33+x (SiO 4 ) 6 O 2+3x/2 has been investigated by combining the atomic pair distribution function (PDF) method, conventional X-ray and neutron powder diffraction (NPD) data and density functional theory (DFT) calculations. DFT was used to build structure models with stable positions of excess oxide ions within the conduction channel. Two stable interstitial positions were obtained in accordance with literature, the first one located at the very periphery of the conduction channel, neighbouring the SiO 4 tetrahedral units, and the second one closer to the channel axis. The corresponding PDFs and average structures were then calculated and tested against experimental PDFs obtained by X-ray total scattering and NPD Rietveld refinements results gathered from literature. It was shown that of the two stable interstitial positions obtained with DFT only the second one located within the channel is consistent with experimental data. This result consolidates one of the two main conduction mechanisms along the c-axis reported in the literature, namely the one involving cooperative movement of O4 and Oi ions.

Local structure and oxide-ion conduction mechanism in apatite-type lanthanum silicates

PubMed Central

Masson, Olivier; Berghout, Abid; Béchade, Emilie; Jouin, Jenny; Thomas, Philippe; Asaka, Toru; Fukuda, Koichiro

2017-01-01

Abstract The local structure of apatite-type lanthanum silicates of general formula La9.33+x(SiO4)6O2+3x/2 has been investigated by combining the atomic pair distribution function (PDF) method, conventional X-ray and neutron powder diffraction (NPD) data and density functional theory (DFT) calculations. DFT was used to build structure models with stable positions of excess oxide ions within the conduction channel. Two stable interstitial positions were obtained in accordance with literature, the first one located at the very periphery of the conduction channel, neighbouring the SiO4 tetrahedral units, and the second one closer to the channel axis. The corresponding PDFs and average structures were then calculated and tested against experimental PDFs obtained by X-ray total scattering and NPD Rietveld refinements results gathered from literature. It was shown that of the two stable interstitial positions obtained with DFT only the second one located within the channel is consistent with experimental data. This result consolidates one of the two main conduction mechanisms along the c-axis reported in the literature, namely the one involving cooperative movement of O4 and Oi ions. PMID:28970872

Local structure and oxide-ion conduction mechanism in apatite-type lanthanum silicates

NASA Astrophysics Data System (ADS)

Masson, Olivier; Berghout, Abid; Béchade, Emilie; Jouin, Jenny; Thomas, Philippe; Asaka, Toru; Fukuda, Koichiro

2017-12-01

The local structure of apatite-type lanthanum silicates of general formula La9.33+x(SiO4)6O2+3x/2 has been investigated by combining the atomic pair distribution function (PDF) method, conventional X-ray and neutron powder diffraction (NPD) data and density functional theory (DFT) calculations. DFT was used to build structure models with stable positions of excess oxide ions within the conduction channel. Two stable interstitial positions were obtained in accordance with literature, the first one located at the very periphery of the conduction channel, neighbouring the SiO4 tetrahedral units, and the second one closer to the channel axis. The corresponding PDFs and average structures were then calculated and tested against experimental PDFs obtained by X-ray total scattering and NPD Rietveld refinements results gathered from literature. It was shown that of the two stable interstitial positions obtained with DFT only the second one located within the channel is consistent with experimental data. This result consolidates one of the two main conduction mechanisms along the c-axis reported in the literature, namely the one involving cooperative movement of O4 and Oi ions.

Structural evolution of Li{sub x}Mn{sub 2}O{sub 4} in lithium-ion battery cells measured in situ using synchrotron X-ray diffraction techniques

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

Mukerjee, S.; Thurston, T.R.; Jisrawi, N.M.

The authors describe synchrotron based X-ray diffraction techniques and issues related to in situ studies of intercalation processes in battery electrodes. They then demonstrate the utility of this technique, through a study of two batches of Li{sub x}Mn{sub 2}O{sub 4} cathode materials. The structural evolution of these spinel materials was monitored in situ during the initial charge of these electrodes in actual battery cells. Significant differences were observed in the two batches, particularly in the intercalation range of x = 0.45 to 0.20. The first-order structural transitions in this region indicated coexistence of two cubic phases in the batch 2more » material, whereas the batch 1 material showed suppressed two-phase coexistence. Batch 2 cells also indicated structural evolution in the low-potential region below 3.0 V in contrast to the batch 1 material. Differences in structural evolution between batches of Li{sub x}Mn{sub 2}O{sub 4} could have important ramifications in their cycle life and stability characteristics.« less

Chemical imaging analysis of the brain with X-ray methods

NASA Astrophysics Data System (ADS)

Collingwood, Joanna F.; Adams, Freddy

2017-04-01

Cells employ various metal and metalloid ions to augment the structure and the function of proteins and to assist with vital biological processes. In the brain they mediate biochemical processes, and disrupted metabolism of metals may be a contributing factor in neurodegenerative disorders. In this tutorial review we will discuss the particular role of X-ray methods for elemental imaging analysis of accumulated metal species and metal-containing compounds in biological materials, in the context of post-mortem brain tissue. X-rays have the advantage that they have a short wavelength and can penetrate through a thick biological sample. Many of the X-ray microscopy techniques that provide the greatest sensitivity and specificity for trace metal concentrations in biological materials are emerging at synchrotron X-ray facilities. Here, the extremely high flux available across a wide range of soft and hard X-rays, combined with state-of-the-art focusing techniques and ultra-sensitive detectors, makes it viable to undertake direct imaging of a number of elements in brain tissue. The different methods for synchrotron imaging of metals in brain tissues at regional, cellular, and sub-cellular spatial resolution are discussed. Methods covered include X-ray fluorescence for elemental imaging, X-ray absorption spectrometry for speciation imaging, X-ray diffraction for structural imaging, phase contrast for enhanced contrast imaging and scanning transmission X-ray microscopy for spectromicroscopy. Two- and three-dimensional (confocal and tomographic) imaging methods are considered as well as the correlation of X-ray microscopy with other imaging tools.

JMFA2—a graphically interactive Java program that fits microfibril angle X-ray diffraction data

Treesearch

Steve P. Verrill; David E. Kretschmann; Victoria L. Herian

2006-01-01

X-ray diffraction techniques have the potential to decrease the time required to determine microfibril angles dramatically. In this paper, we discuss the latest version of a curve-fitting toll that permits us to reduce the time required to evaluate MFA X-ray diffraction patterns. Further, because this tool reflects the underlying physics more accurately than existing...

Biomineralization of hydroxyapatite in silver ion-exchanged nanocrystalline ZSM-5 zeolite using simulated body fluid.

PubMed

Kaur, Balwinder; Srivastava, Rajendra; Satpati, Biswarup; Kondepudi, Kanthi Kiran; Bishnoi, Mahendra

2015-11-01

Silver ion-exchanged nanocrystalline zeolite (Ag-Nano-ZSM-5) and silver ion-exchanged conventional zeolite (Ag-ZSM-5) were synthesized. Zeolites were incubated in simulated body fluid at 310K for different time periods to grow hydroxyapatite in their matrixes. Significant large amount of hydroxyapatite was grown in Ag-Nano-ZSM-5 matrix after incubation in simulated body fluid when compared to Ag-ZSM-5. The resultant material was characterized using X-ray diffraction, N2-adsorption, scanning/transmission electron microscopy, energy dispersive X-ray, and inductively coupled plasma analysis. Mechanical properties such as compressive modulus, compressive strength, and strain at failure of the parent materials were evaluated. Biocompatibility assays suggested that Ag-Nano-ZSM-5 and hydroxyapatite grown in Ag-Nano-ZSM-5 were compatible and did not impose any toxicity to RAW 264.7 cells macrophase and Caco2 cells suggesting considerable potential for biomedical applications such as bone implants. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of Ar{sup +} ion irradiation on the microstructure of pyrolytic carbon

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

Feng, Shanglei; Zhang, Dongsheng; Yang, Xinmei

2015-03-21

Pyrolytic carbon (PyC) coatings prepared by chemical vapor deposition were irradiated by 300 keV Ar{sup +} ions. Then, atomic force microscopy, synchrotron-based grazing incidence X-ray diffraction, Raman spectroscopy, X-ray photoemission spectroscopy, and transmission electron microscopy were employed to study how Ar{sup +} irradiation affects the microstructure of PyC, including the microstructural damage mechanisms and physics driving these phenomena. The 300 keV Ar{sup +} ion irradiation deteriorated the structure along the c-axis, which increased the interlayer spacing between graphene layers. With increasing irradiation dose, the density of defect states on the surface of PyC coating increases, and the basal planes gradually loses theirmore » initial ordering resulting in breaks in the lattice and turbulence at the peak damage dose reaches 1.58 displacement per atom (dpa). Surprisingly, the PyC becomes more textured as it becomes richer in structural defects with increasing irradiation dose.« less

Synthesis of Silver Embedded Poly(o-Anisidine) Molybdophosphate Nano Hybrid Cation-Exchanger Applicable for Membrane Electrode

PubMed Central

Khan, Anish; Khan, Aftab Aslam Parwaz; Asiri, Abdullah M.; Rub, Malik Abdul

2014-01-01

Poly(o-anisidine) molybdophosphate was expediently obtained by sol-gel mixing of Poly(o-anisidine) into the inorganic matrices of molybdophosphate, which was allowed to react with silver nitrate to the formation of poly(o-anisidine) molybdophosphate embedded silver nano composite. The composite was characterized by Fourier Transform Infrared Spectroscopy, X-ray powder diffraction, UV-Vis Spectrophotometry, Fluorescence Spectroscopy, Scanning Electron Microscopy/Energy-dispersive X-ray Spectroscopy and Thermogravimertic Analysis. Ion exchange capacity and distribution studies were carried out to understand the ion-exchange capabilities of the nano composite. On the basis of highest distribution studies, this nano composite cation exchanger was used as preparation of heavy metal ion selective membrane. Membrane was characterized for its performance as porosity and swelling later on was used for the preparation of membrane electrode for Hg(II), having better linear range, wide working pH range (2–4.5) with fast response in the real environment. PMID:24805257

Surface and grain boundary interdiffusion in nanometer-scale LSMO/BFO bilayer

NASA Astrophysics Data System (ADS)

Kumar, Virendra; Gaur, Anurag; Choudhary, R. J.; Gupta, Mukul

2016-05-01

Epitaxial 150 nm thick LSMO/BFO bilayer is deposited on STO (100) substrate by pulsed laser deposition, to study magnetoelectric effect. Unexpected low value of room temperature magnetization in bilayer indicates towards the possibility of interdiffusion. Further, sharp fall in the value of TC (53 K) also added our anxiety towards possible interdiffusion in BFO/LSMO system. Low-angle x-ray diffraction technique is used to investigate interdiffusion phenomena, and the temperature-dependent interdiffusivity is obtained by accurately monitoring the decay of the first-order modulation peak as a function of annealing time. It has been found that the diffusivity at different temperatures follows Arrhenius-type behavior. X-ray reflection (XRR) pattern obtained for the bilayer could not be fitted in the Parratt's formalism, which confirms the interdiffusion in it. Depth profiles of 209Bi, 56Fe ions measured by secondary ion mass spectroscope (SIMS) further substantiate the diffusion of these ions from upper BFO layer into lower LSMO layer.

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

Yadav, Praveen Kumar, E-mail: praveenyadav@rrcat.gov.in; Nayak, Maheswar; Rai, Sanjay Kumar

The authors report the effect of argon ion to molybdenum atom ratio (r) on the microstructure of low energy (70 eV) argon ion assisted electron beam evaporated Mo thin films. Surface roughness, morphology, and crystallinity of Mo films are found to strongly depend on “r.” Increase of “r” from 0 to 100 induces gradual loss in crystallinity, reduction in surface roughness and systematic increase in density of the film. For “r” ∼ 100, average atomic density of the film approaches the bulk value (97%) with lowest surface roughness. Further, increasing “r” up to 170 reduces the atomic density, increases roughness, and increase inmore » crystallinity induced by low energy Ar ion beam. The observed surface roughness and grain size determined by x-ray reflectivity and glancing incidence x-ray diffraction correlate well with atomic force microscopy measurements. This study demonstrates that for r = 100 one gets lowest roughness Mo film with highest density and nearly amorphous microstructure. The growth model is discussed by structural zone model.« less

1D cyanide complexes with 2-pyridinemethanol: Synthesis, crystal structures and spectroscopic properties

NASA Astrophysics Data System (ADS)

Sayın, Elvan; Kürkçüoğlu, Güneş Süheyla; Yeşilel, Okan Zafer; Hökelek, Tuncer

2015-12-01

Two new one-dimensional coordination polymers, [Cu(hmpH)2Pd(μ-CN)2(CN)2]n (1) and [Cu(hmpH)2Pt(μ-CN)2(CN)2]n (2), (hmpH = 2-pyridinemethanol), have been synthesized and characterized by vibrational (FT-IR and Raman) spectroscopy, single crystal X-ray diffraction, thermal and elemental analyses techniques. Single crystal X-ray diffraction analysis indicates that complexes 1 and 2 are isomorphous and isostructural, and crystallize in the triclinic system and P-1 space group. The Pd(II) or Pt(II) ions are four coordinated with four cyanide-carbon atoms in a square planar geometry. Cu(II) ion displays a distorted octahedral coordination by two N-atoms and two O-atoms of hmpH ligands, two bridging cyanide groups. In one dimensional structure of the complexes, [M(CN)4]2- (M = Pd(II) or Pt(II)) anions and [Cu(hmpH)2]2+ cations are linked via bridging cyanide ligands. In the complexes, the presence of intramolecular C-H⋯M (M = Pd(II) or Pt(II)) interactions with distance values of 3.00-2.95 Å are established, respectively.

Adsorption and photocatalytic properties of transition metal Zinc(II) complex based on 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid

NASA Astrophysics Data System (ADS)

Qiao, Yu; Ren, Shan-Shan; Liu, Li-Hui; Guan, Wei-Sheng; Li, Zhi-Min; Che, Guang-Bo; Liu, Chun-Bo; Wang, Yan-Yan; Wang, Qing-Wei; Li, Xiu-Ying; Zhu, En-Wei

2018-06-01

A new coordination polymeric zinc(II) complex, namely, [Zn2(L)(H2O)3]n·nNO3(1), (H3L = 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid) has been synthesized under solvothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction analysis and powder X-ray diffraction. Complex 1 exhibits a three-dimensional structure with a Schläfli symbol of 44•69•82 topologies, constructed from two crystallographically independent five and six coordinated mode with metal center and connected H3L ligands. The complex has good thermal stability and excellent photoluminescent property. Furthermore, by comparing the photoluminescent and photocatalytic mutation results induced by interconversion of metal ions, we confirm that the properties mutation induced by metal ions is much controllable and obvious. In addition, the complex exhibits significantly enhanced photocatalytic activity for methylene blue (MB) under UV light irradiation (λ < 400 nm), and the degradation rate could reach 75% in 80 min. Meanwhile trapping experiments indicated that the •O2- and h+ are the main activated species.

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

DOE PAGES

Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; ...

2015-08-11

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessarymore » to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. In addition, the features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

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

Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessarymore » to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. In addition, the features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

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

Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called `fixed-target' sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary tomore » fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15µm) loaded into the chips yielded a complete, high-resolution (<1.6Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs.« less

A high-transparency, micro-patternable chip for X-ray diffraction analysis of microcrystals under native growth conditions

PubMed Central

Murray, Thomas D.; Lyubimov, Artem Y.; Ogata, Craig M.; Vo, Huy; Uervirojnangkoorn, Monarin; Brunger, Axel T.; Berger, James M.

2015-01-01

Microcrystals present a significant impediment to the determination of macromolecular structures by X-ray diffraction methods. Although microfocus synchrotron beamlines and X-ray free-electron lasers (XFELs) can enable the collection of interpretable diffraction data from microcrystals, there is a need for efficient methods of harvesting small volumes (<2 µl) of microcrystals grown under common laboratory formats and delivering them to an X-ray beam source under native growth conditions. One approach that shows promise in overcoming the challenges intrinsic to microcrystal analysis is to pair so-called ‘fixed-target’ sample-delivery devices with microbeam-based X-ray diffraction methods. However, to record weak diffraction patterns it is necessary to fabricate devices from X-ray-transparent materials that minimize background scattering. Presented here is the design of a new micro-diffraction device consisting of three layers fabricated from silicon nitride, photoresist and polyimide film. The chip features low X-ray scattering and X-ray absorption properties, and uses a customizable blend of hydrophobic and hydrophilic surface patterns to help localize microcrystals to defined regions. Microcrystals in their native growth conditions can be loaded into the chips with a standard pipette, allowing data collection at room temperature. Diffraction data collected from hen egg-white lysozyme microcrystals (10–15 µm) loaded into the chips yielded a complete, high-resolution (<1.6 Å) data set sufficient to determine a high-quality structure by molecular replacement. The features of the chip allow the rapid and user-friendly analysis of microcrystals grown under virtually any laboratory format at microfocus synchrotron beamlines and XFELs. PMID:26457423

X-ray driven channeling acceleration in crystals and carbon nanotubes

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

Shin, Young-Min; Still, Dean A.; Shiltsev, Vladimir

2013-12-01

Acceleration of particles channeling in a crystal by means of diffracted x-rays via Bormann anomalous transmission was conceived for heavy ions and muons by Tajima and Cavenago [Phys. Rev. Lett. 59, 1440 (1987)], which potentially offers an appreciably high field gradient on the order of GV/cm. The theoretical model of the high gradient acceleration has been studied in two kinds of atomic structure, crystals and carbon nanotubes (CNTs), with analytic calculations and electromagnetic eigenmode simulations. A range of acceleration gradients and cutoffs of the x-ray power (the lowest power limit to overcome the Bremsstrahlung radiation losses) are characterized in termsmore » of the lattice constants, unit cell sizes, and photon energies. The parametric analysis indicates that the required x-ray power can be reduced to an order of megawatt by replacing crystals with CNTs. Eventually, the equivalent dielectric approximation of a multi-wall nanotube shows that 250–810 MeV muons can be synchronously coupled with x-rays of 0.65–1.32 keV in the accelerating structure.« less

Effect of Ca2+ Ions on Electrical Properties of Ba1-x Ca x Ti0.90Sn0.10O3-0.05Y2O3 Ceramics

NASA Astrophysics Data System (ADS)

Chen, Zhi-hui; Li, Zhi-wei; Ding, Jian-ning; Zhao, Tian-xiang; Qiu, Jian-hua; Zhu, Ke-qian; Xu, Jiu-jun; Zhang, Bing

2018-03-01

Ba1-x Ca x Ti0.90Sn0.10O3-0.05Y2O3 (BCTSY) lead-free piezoceramics with x = 0.02 to 0.10 have been fabricated by solid-state sintering method at 1420°C. The effects of Ca2+ ions on the microstructure and electrical properties of the samples were studied. X-ray diffraction analysis showed that all samples possessed pure perovskite structure with Ca2+ ions diffused into the matrix lattice. The rhombohedral phase and tetragonal phase coexisted in the composition range of 0.02 < x < 0.06. The microstructure of BCTSY ceramic became more homogeneous with addition of Ca2+ ions, and the average grain size of the samples decreased from 97 μm (x = 0.02) to 18 μm (x = 0.10). Addition of Ca2+ remarkably improved the piezoelectric properties, enhanced the dielectric frequency dispersion, and increased the Curie temperature of the ceramics. The piezoelectric properties of the ceramics were optimized at x = 0.04 with d 33 and K p values of 579 pC/N and 52.7%, respectively.

Effect of Ca2+ Ions on Electrical Properties of Ba1- x Ca x Ti0.90Sn0.10O3-0.05Y2O3 Ceramics

NASA Astrophysics Data System (ADS)

Chen, Zhi-hui; Li, Zhi-wei; Ding, Jian-ning; Zhao, Tian-xiang; Qiu, Jian-hua; Zhu, Ke-qian; Xu, Jiu-jun; Zhang, Bing

2018-07-01

Ba1- x Ca x Ti0.90Sn0.10O3-0.05Y2O3 (BCTSY) lead-free piezoceramics with x = 0.02 to 0.10 have been fabricated by solid-state sintering method at 1420°C. The effects of Ca2+ ions on the microstructure and electrical properties of the samples were studied. X-ray diffraction analysis showed that all samples possessed pure perovskite structure with Ca2+ ions diffused into the matrix lattice. The rhombohedral phase and tetragonal phase coexisted in the composition range of 0.02 < x < 0.06. The microstructure of BCTSY ceramic became more homogeneous with addition of Ca2+ ions, and the average grain size of the samples decreased from 97 μm ( x = 0.02) to 18 μm ( x = 0.10). Addition of Ca2+ remarkably improved the piezoelectric properties, enhanced the dielectric frequency dispersion, and increased the Curie temperature of the ceramics. The piezoelectric properties of the ceramics were optimized at x = 0.04 with d 33 and K p values of 579 pC/N and 52.7%, respectively.

Quantitative x-ray diffraction analysis of bimodal damage distributions in Tm implanted Al0.15Ga0.85N

NASA Astrophysics Data System (ADS)

Magalhães, S.; Fialho, M.; Peres, M.; Lorenz, K.; Alves, E.

2016-04-01

In this work radial symmetric x-ray diffraction scans of Al0.15Ga0.85N thin films implanted with Tm ions were measured to determine the lattice deformation and crystal quality as functions of depth. The alloys were implanted with 300 keV Tm with 10° off-set to the sample normal to avoid channelling, with fluences varying between 1013 Tm cm-2 and 5  ×  1015 Tm cm-2. Simulations of the radial 2θ-ω scans were performed under the frame of the dynamical theory of x-ray diffraction assuming Gaussian distributions of the lattice strain induced by implantation defects. The structure factor of the individual layers is multiplied by a static Debye-Waller factor in order to take into account the effect of lattice disorder due to implantation. For higher fluences two asymmetric Gaussians are required to describe well the experimental diffractograms, although a single asymmetric Gaussian profile for the deformation is found in the sample implanted with 1013 Tm cm-2. After thermal treatment at 1200 °C, the crystal quality partially recovers as seen in a reduction of the amplitude of the deformation maximum as well as the total thickness of the deformed layer. Furthermore, no evidence of changes with respect to the virgin crystal mosaicity is found after implantation and annealing.

High-resolution x-ray diffraction microscopy of specifically labeled yeast cells

PubMed Central

Nelson, Johanna; Huang, Xiaojing; Steinbrener, Jan; Shapiro, David; Kirz, Janos; Marchesini, Stefano; Neiman, Aaron M.; Turner, Joshua J.; Jacobsen, Chris

2010-01-01

X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolution limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (11–13 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of molecular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lectin concanavalin A conjugated to colloidal gold particles was used to label the α-mannan sugar in the cell wall of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane and freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy. PMID:20368463

High-resolution x-ray diffraction microscopy of specifically labeled yeast cells

DOE PAGES

Nelson, Johanna; Huang, Xiaojing; Steinbrener, Jan; ...

2010-04-20

X-ray diffraction microscopy complements other x-ray microscopy methods by being free of lens-imposed radiation dose and resolution limits, and it allows for high-resolution imaging of biological specimens too thick to be viewed by electron microscopy. We report here the highest resolution (11-13 nm) x-ray diffraction micrograph of biological specimens, and a demonstration of molecular-specific gold labeling at different depths within cells via through-focus propagation of the reconstructed wavefield. The lectin concanavalin A conjugated to colloidal gold particles was used to label the α-mannan sugar in the cell wall of the yeast Saccharomyces cerevisiae. Cells were plunge-frozen in liquid ethane andmore » freeze-dried, after which they were imaged whole using x-ray diffraction microscopy at 750 eV photon energy.« less

Roughness measurement and ion-beam polishing of super-smooth optical surfaces of fused quartz and optical ceramics.

PubMed

Chkhalo, N I; Churin, S A; Pestov, A E; Salashchenko, N N; Vainer, Yu A; Zorina, M V

2014-08-25

The main problems and the approach used by the authors for roughness metrology of super-smooth surfaces designed for diffraction-quality X-ray mirrors are discussed. The limitations of white light interferometry and the adequacy of the method of atomic force microscopy for surface roughness measurements in a wide range of spatial frequencies are shown and the results of the studies of the effect of etching by argon and xenon ions on the surface roughness of fused quartz and optical ceramics, Zerodur, ULE and Sitall, are given. Substrates of fused quartz and ULE with the roughness, satisfying the requirements of diffraction-quality optics intended for working in the spectral range below 10 nm, are made.

Phase coexistence and magnetic behavior in the low-dimensional hexagonal cobaltites BaxA1-xCoO3-δ (A = Mg or Ca and 0 ⩽ x ⩽ 0.20)

NASA Astrophysics Data System (ADS)

Oliveira, M. P.; Mercena, S. G.; Meneses, C. T.; Jesus, C. B. R.; Pagliuso, P. G.; Duque, J. G. S.

2018-04-01

In this work, we report on X-ray diffraction and magnetization measurements carried out in the low-dimensional hexagonal cobaltites BaxA1-xCoO3-δ (A = Mg or Ca, 0 ⩽ x ⩽ 0.20 and δ = 0 or 0.4). Polycrystalline samples have been synthesized by solid-state reaction. The Rietveld refinements of the X-ray diffraction patterns show clearly a phase coexistence of both BaCoO2.6 and BaCoO3 hexagonal polytype structures (space group: P63/mmc), which is dependent on both the dopant ion and doping level. At low temperatures (T < 50K), the ZFC-FC data recorded at H = 1 kOe for Ca-doped (x < 0.15) and Ba0.80Mg0.20CoO3-δ samples present a broad peak and strong thermal hysteresis. Besides, a second anomaly around room temperature is also observed in susceptibility curves for all samples. Further increasing in the Ca-doping produces a continuous decreasing of magnetization and for the samples with x > 0.10 the low temperature hysteresis is not observed anymore. The field-dependence of ZFC-FC curves taken for the sample grown with x = 0 show a displacement of the peak position into low temperature region. Except for the sample grown with x = 0.20, the MvsH loops taken at T = 2 K show multiple steps in the field region ranging - 15 ⩽ H ⩽ 15 kOe . Finally, the saturation magnetization values are consistent with a low-spin state for the Co2+ or Co4+ ions.

Coherent x-ray zoom condenser lens for diffractive and scanning microscopy.

PubMed

Kimura, Takashi; Matsuyama, Satoshi; Yamauchi, Kazuto; Nishino, Yoshinori

2013-04-22

We propose a coherent x-ray zoom condenser lens composed of two-stage deformable Kirkpatrick-Baez mirrors. The lens delivers coherent x-rays with a controllable beam size, from one micrometer to a few tens of nanometers, at a fixed focal position. The lens is suitable for diffractive and scanning microscopy. We also propose non-scanning coherent diffraction microscopy for extended objects by using an apodized focused beam produced by the lens with a spatial filter. The proposed apodized-illumination method will be useful in highly efficient imaging with ultimate storage ring sources, and will also open the way to single-shot coherent diffraction microscopy of extended objects with x-ray free-electron lasers.

Scanning force microscope for in situ nanofocused X-ray diffraction studies

PubMed Central

Ren, Zhe; Mastropietro, Francesca; Davydok, Anton; Langlais, Simon; Richard, Marie-Ingrid; Furter, Jean-Jacques; Thomas, Olivier; Dupraz, Maxime; Verdier, Marc; Beutier, Guillaume; Boesecke, Peter; Cornelius, Thomas W.

2014-01-01

A compact scanning force microscope has been developed for in situ combination with nanofocused X-ray diffraction techniques at third-generation synchrotron beamlines. Its capabilities are demonstrated on Au nano-islands grown on a sapphire substrate. The new in situ device allows for in situ imaging the sample topography and the crystallinity by recording simultaneously an atomic force microscope (AFM) image and a scanning X-ray diffraction map of the same area. Moreover, a selected Au island can be mechanically deformed using the AFM tip while monitoring the deformation of the atomic lattice by nanofocused X-ray diffraction. This in situ approach gives access to the mechanical behavior of nanomaterials. PMID:25178002

Synthesis and Use of [Cd(Detu)2(OOCCH3)2]·H2O as Single Molecule Precursor for Cds Nanoparticles

PubMed Central

Ajibade, Peter A.

2013-01-01

Substituted thiourea ligands are of interest because they possess various donor sites for metal ions and their application in separation of metal ions and as antimicrobial agents. The coordination of the sulfur donor atom led to interest in them as precursor for semiconductor nanoparticles. In this study, cadmium(II) complex of diethylthiourea was synthesized and characterized by elemental analysis, FTIR, and X-ray crystallography. Single crystal X-ray structure of the complex showed that the octahedral geometry around the Cd ion consists of two molecules of diethylthiourea acting as monodentate ligands and two chelating acetate ions. The thermal decomposition of the compound showed that it decomposed to give CdS. The compound was thermolysed in hexadecylamine (HDA) to prepare HDA-capped CdS nanoparticles. The absorption spectrum showed blue shifts in its absorption band edges which clearly indicated quantum confinement effect, and the emission spectrum showed characteristic band edge luminescence. The broad diffraction peaks of the XRD pattern showed the materials to be of the nanometric size. PMID:24294141

Elucidation of reaction mechanisms of Ni2SnP in Li-ion and Na-ion systems

NASA Astrophysics Data System (ADS)

Marino, C.; Dupré, N.; Villevieille, C.

2017-10-01

Electrochemical performance of Ni2SnP was assessed in Li-ion and Na-ion battery systems. When cycled versus Li, Ni2SnP exhibited a reversible specific charge of 700 mAh.g-1 (theoretical specific charge: 742 mAh.g-1). In the Na system, the specific observed charge was ca. 200 mAh.g-1 (theoretical specific charge: 676 mAh.g-1). X-ray diffraction, Ni K-edge X-ray absorption spectroscopy, and 31P and 7Li/23Na nuclear magnetic resonance spectroscopy were used to elucidate the electrochemical mechanisms in both systems. Versus Li, Ni2SnP undergoes a conversion reaction resulting in the extrusion of Ni and the alloying of Li-Sn and Li-P. On delithiation, the material partially recombines into a Sn- and Ni-deficient form. In the Na system, Ni2SnP reacts through the conversion of P into Na3P. These results indicate that the recombination of the pristine material (even partially) increases cycling stability.

Synthesis of Cu/CuO nanoparticles in mesoporous material by solid state reaction

NASA Astrophysics Data System (ADS)

Sohrabnezhad, Sh.; Valipour, A.

2013-10-01

The Mobil Composition of Matter No. 41 (MCM-41) containing 1.0 and 5.0 wt.% of Cu was synthesized under solid state reaction. The calcinations of samples were done at two different temperatures, 500 and 300 °C. X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) were used for samples characterization. Powder X-ray diffraction showed that when Cu(CH3COO)2 content is about 1.0 wt.% in Cu/MCM-41, the guest CuO-NPs and copper ions is formed on the silica channel wall, and more exists in the crystalline state. When Cu(CH3COO)2 content exceeds this value (5.0 wt.%), CuO nanoparticles and Cu2+ ions can be observed in low crystalline state. From the diffuse reflectance spectra it was confirmed that 5 wt.% Cu/MCM-41 sample calcined at 500 °C show plasmon resonance band due to Cu nanoparticles in the range between 500 and 600 nm and small copper clusters Cun in 450 nm. It also shows that some of the Cu2+ ions are present octahedrally in extraframework position in all samples. Both fourier transform infrared and diffuse reflectance spectra indicate that some of Cu2+ ions are tetrahedrally within the framework position in 1 wt.% Cu/MCM-41 samples. TEM images indicated that nanoparticles size of CuO is in range of 30-40 nm.

Speciation of platinum(IV) in nitric acid solutions.

PubMed

Vasilchenko, Danila; Tkachev, Sergey; Baidina, Iraida; Korenev, Sergey

2013-09-16

The speciation of platinum(IV) ions in nitric acid (6-15.8 M) solutions of H2[Pt(OH)6] has been studied by (195)Pt NMR and Raman spectroscopy. Series of aqua-hydroxo-nitrato complexes [Pt(L)(x)(NO3)(6-x)] (L = H2O or OH(-); x = 0, ..., 6) were found to exist in such solutions. The pair additivity model of chemical shifts and statistical theory were used to assign signals in NMR spectra to particular [Pt(L)(x)(NO3)(6-x)] species. Mononuclear hexanitratoplatinates(IV) have been isolated in solid state in substantial yield as pyridinium salt (PyH)2[Pt(NO3)6] and characterized by single-crystal X-ray diffraction. Aging of the platinum nitric acid solutions for more than 5-6 h results in oligomerization of [Pt(L)(x)(NO3)(6-x)] species and the formation of oligonuclear aqua-hydroxo-nitrato complexes with OH(-) and NO3(-) bridging ligands. Oligomeric platinum(IV) complexes with two and four nuclei were unambiguously detected by NMR on (195)Pt -enriched samples. Oligomers with even higher nuclearity were also detected. Dimeric anions [Pt2(μ-OH)2(NO3)8](2-) have been isolated as single crystals of tetramethylammonium salt and characterized by X-ray diffraction.

X-ray topography using the forward transmitted beam under multiple-beam diffraction conditions

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

Tsusaka, Y., E-mail: tsusaka@sci.u-hyogo.ac.jp; Takano, H.; Takeda, S.

2016-02-15

X-ray topographs are taken for a sapphire wafer with the [0001] surface normal, as an example, by forward transmitted synchrotron x-ray beams combined with two-dimensional electronic arrays in the x-ray detector having a spatial resolution of 1 μm. They exhibit no shape deformation and no position shift of the dislocation lines on the topographs. Since the topography is performed under multiple-beam diffraction conditions, the topographic images of a single diffraction (two-wave approximation condition) or plural diffractions (six-wave approximation condition) can be recorded without large specimen position changes. As usual Lang topographs, it is possible to determine the Burgers vector ofmore » each dislocation line. Because of high parallelism of the incoming x-rays and linear sensitivity of the electronic arrays to the incident x-rays, the present technique can be used to visualize individual dislocations in single crystals of the dislocation density as high as 1 × 10{sup 5} cm{sup −2}.« less

Monomolecular Siloxane Film as a Model of Single Site Catalysts

DOE PAGES

Martynowycz, Michael W.; Hu, Bo; Kuzmenko, Ivan; ...

2016-09-06

Achieving structurally well-defined catalytic species requires a fundamental understanding of surface chemistry. Detailed structural characterization of the catalyst binding sites in situ, such as single site catalysts on silica supports, is technically challenging or even unattainable. Octadecyltrioxysilane (OTOS) monolayers formed from octadecyltrimethoxysilane (OTMS) at the air-liquid interface after hydrolysis and condensation at low pH were chosen as a model system of surface binding sites in silica-supported Zn 2+ catalysts. We characterize the system by grazing incidence X-ray diffraction, X-ray reflectivity (XR), and X-ray fluorescence spectroscopy (XFS). Previous X-ray and infrared surface studies of OTMS/OTOS films at the airliquid interface proposedmore » the formation of polymer OTOS structures. According to our analysis, polymer formation is inconsistent with the X-ray observations and structural properties of siloxanes; it is energetically unfavorable and thus highly unlikely. We suggest an alternative mechanism of hydrolysis/condensation in OTMS leading to the formation of structurally allowed cyclic trimers with the six-membered siloxane rings, which explain well both the X-ray and infrared results. XR and XFS consistently demonstrate that tetrahedral [Zn(NH 3) 4] 2+ ions bind to hydroxyl groups of the film at a stoichiometric ratio of OTOS:Zn ~ 2:1. The high binding affinity of zinc ions to OTOS trimers suggests that the six-membered siloxane rings are binding locations for single site Zn/SiO 2 catalysts. Finally, our results show that OTOS monolayers may serve as a platform for studying silica surface chemistry or hydroxyl-mediated reactions.« less

Synthesis and electrochemical characterization of Silicon clathrates as anode materials for Lithium ion batteries

NASA Astrophysics Data System (ADS)

Raghavan, Rahul

Novel materials for Li-ion batteries is one of the principle thrust areas for current research in energy storage, more so than most, considering its widespread use in portable electronic gadgets and plug-in electric and hybrid cars. One of the major limiting factors in a Li-ion battery's energy density is the low specific capacities of the active materials in the electrodes. In the search for high-performance anode materials for Li-ion batteries, many alternatives to carbonaceous materials have been studied. Both cubic and amorphous silicon can reversibly alloy with lithium and have a theoretical capacity of 3500 mAh/g, making silicon a potential high density anode material. However, a large volume expansion of 300% occurs due to changes in the structure during lithium insertion, often leading to pulverization of the silicon. To this end, a class of silicon based cage compounds called clathrates are studied for electrochemical reactivity with lithium. Silicon-clathrates consist of silicon covalently bonded in cage structures comprised of face sharing Si20, Si24 and/or Si28 clusters with guest ions occupying the interstitial positions in the polyhedra. Prior to this, silicon clathrates have been studied primarily for their superconducting and thermoelectric properties. In this work, the synthesis and electrochemical characterization of two categories of silicon clathrates - Type-I silicon clathrate with aluminum framework substitution and barium guest ions (Ba8AlxSi46-x) and Type-II silicon clathrate with sodium guest ions (Nax Si136), are explored. The Type-I clathrate, Ba8AlxSi46-x consists of an open framework of aluminium and silicon, with barium (guest) atoms occupying the interstitial positions. X-ray diffraction studies have shown that a crystalline phase of clathrate is obtained from synthesis, which is powdered to a fine particle size to be used as the anode material in a Li-ion battery. Electrochemical measurements of these type of clathrates have shown that capacities comparable to graphite can be obtained for up to 10 cycles and lower capacities can be obtained for up to 20 cycles. Unlike bulk silicon, the clathrate structure does not undergo excessive volume change upon lithium intercalation, and therefore, the crystal structure is morphologically stable over many cycles. X-ray diffraction of the clathrate after cycling showed that crystallinity is intact, indicating that the clathrate does not collapse during reversible intercalation with lithium ions. Electrochemical potential spectroscopy obtained from the cycling data showed that there is an absence of formation of lithium-silicide, which is the product of lithium alloying with diamond cubic silicon. Type II silicon clathrate, NaxSi136, consists of silicon making up the framework structure and sodium (guest) atoms occupying the interstitial spaces. These clathrates showed very high capacities during their first intercalation cycle, in the range of 3,500 mAh/g, but then deteriorated during subsequent cycles. X-ray diffraction after one cycle showed the absence of clathrate phase and the presence of lithium-silicide, indicating the disintegration of clathrate structure. This could explain the silicon-like cycling behavior of Type II clathrates.

Adsorption of Cd2+ ions on plant mediated SnO2 nanoparticles

NASA Astrophysics Data System (ADS)

Haq, Sirajul; Rehman, Wajid; Waseem, Muhammad; Shahid, Muhammad; Mahfooz-ur-Rehman; Hussain Shah, Khizar; Nawaz, Mohsan

2016-10-01

Plant mediated SnO2 nanoparticles were synthesized by using SnCl4.5H2O as a precursor material. The nanoparticles were then characterized for BET surface area measurements, energy dispersive x-rays (EDX), scanning electron microscopy (SEM), UV-vis diffuse reflectance (DRS) spectra and x-rays diffraction (XRD) analysis. The successful synthesis of SnO2 nanoparticles was confirmed by EDX analysis. The particle sizes were in the range 19-27 nm whereas the crystallite size computed from XRD measurement was found to be 19.9 nm. Batch adsorption technique was employed for the removal of Cd2+ ions from aqueous solution. The sorption studies of Cd2+ ions were performed at pHs 4 and 6. The equilibrium concentration of Cd2+ ions was determined by atomic absorption spectrometer (flame mode). The uptake of Cd2+ ions was affected by initial concentration, pH and temperature of the electrolytic solution. It was observed that the adsorption of Cd2+ ions enhanced with increase in the initial concentration of Cd2+ ions whereas a decrease in the percent adsorption was detected. From the thermodynamic parameters, the adsorption process was found spontaneous and endothermic in nature. The n values confirmed 2:1 exchange mechanism between surface protons and Cd2+ ions.

Multiple defocused coherent diffraction imaging: method for simultaneously reconstructing objects and probe using X-ray free-electron lasers.

PubMed

Hirose, Makoto; Shimomura, Kei; Suzuki, Akihiro; Burdet, Nicolas; Takahashi, Yukio

2016-05-30

The sample size must be less than the diffraction-limited focal spot size of the incident beam in single-shot coherent X-ray diffraction imaging (CXDI) based on a diffract-before-destruction scheme using X-ray free electron lasers (XFELs). This is currently a major limitation preventing its wider applications. We here propose multiple defocused CXDI, in which isolated objects are sequentially illuminated with a divergent beam larger than the objects and the coherent diffraction pattern of each object is recorded. This method can simultaneously reconstruct both objects and a probe from the coherent X-ray diffraction patterns without any a priori knowledge. We performed a computer simulation of the prposed method and then successfully demonstrated it in a proof-of-principle experiment at SPring-8. The prposed method allows us to not only observe broad samples but also characterize focused XFEL beams.

Angular rheology study of colloidal nanocrystals using Coherent X-ray Diffraction

NASA Astrophysics Data System (ADS)

Liang, Mengning; Harder, Ross; Robinson, Ian

2007-03-01

A new method using coherent x-ray diffraction provides a way to investigate the rotational motion of a colloidal suspension of crystals in real time. Coherent x-ray diffraction uses the long coherence lengths of synchrotron sources to illuminate a nanoscale particle coherently over its spatial dimensions. The penetration of high energy x-rays into various media allows for in-situ measurements making it ideal for suspensions. This technique has been used to image the structure of nanocrystals for some time but also has the capability of providing information about the orientation and dynamics of crystals. The particles are imaged in a specific diffraction condition allowing us to determine their orientation and observe how they rotate in real time with exceptional resolution. Such sensitivity allows for the study of rotational Brownian motion of nanocrystals in various suspensions and conditions. We present a study of the angular rheology of alumina and TiO2 colloidal nanocrystals in media using coherent x-ray diffraction.

Characterization of polycrystalline materials using synchrotron X-ray imaging and diffraction techniques

NASA Astrophysics Data System (ADS)

Ludwig, W.; King, A.; Herbig, M.; Reischig, P.; Marrow, J.; Babout, L.; Lauridsen, E. M.; Proudhon, H.; Buffière, J. Y.

2010-12-01

The combination of synchrotron radiation x-ray imaging and diffraction techniques offers new possibilities for in-situ observation of deformation and damage mechanisms in the bulk of polycrystalline materials. Minute changes in electron density (i.e., cracks, porosities) can be detected using propagation based phase contrast imaging, a 3-D imaging mode exploiting the coherence properties of third generation synchrotron beams. Furthermore, for some classes of polycrystalline materials, one may use a 3-D variant of x-ray diffraction imaging, termed x-ray diffraction contrast tomography. X-ray diffraction contrast tomography provides access to the 3-D shape, orientation, and elastic strain state of the individual grains from polycrystalline sample volumes containing up to thousand grains. Combining both imaging modalities, one obtains a comprehensive description of the materials microstructure at the micrometer length scale. Repeated observation during (interrupted) mechanical tests provide unprecedented insight into crystallographic and grain microstructure related aspects of polycrystalline deformation and degradation mechanisms.

Quantitative analysis of thoria phase in Th-U alloys using diffraction studies

NASA Astrophysics Data System (ADS)

Thakur, Shital; Krishna, P. S. R.; Shinde, A. B.; Kumar, Raj; Roy, S. B.

2017-05-01

In the present study the quantitative phase analysis of Th-U alloys in bulk form namely Th-52 wt% U and Th-3wt%U has been performed over the data obtained from both X ray diffraction and neutron diffraction technique using Rietveld method of FULLPROF software. Quantifying thoria (ThO2) phase present in bulk of the sample is limited due to surface oxidation and low penetration of x rays in high Z material. Neutron diffraction study probing bulk of the samples has been presented in comparison with x-ray diffraction study.

Glancing-incidence focussed ion beam milling: A coherent X-ray diffraction study of 3D nano-scale lattice strains and crystal defects

DOE PAGES

Hofmann, Felix; Harder, Ross J.; Liu, Wenjun; ...

2018-05-11

Here, this study presents a detailed examination of the lattice distortions introduced by glancing incidence Focussed Ion Beam (FIB) milling. Using non-destructive multi-reflection Bragg coherent X-ray diffraction we probe damage formation in an initially pristine gold micro-crystal following several stages of FIB milling. These experiments allow access to the full lattice strain tensor in the micro-crystal with ~25 nm 3D spatial resolution, enabling a nano-scale analysis of residual lattice strains and defects formed. Our results show that 30 keV glancing incidence milling produces fewer large defects than normal incidence milling at the same energy. However the resulting residual lattice strainsmore » have similar magnitude and extend up to ~50 nm into the sample. At the edges of the milled surface, where the ion-beam tails impact the sample at near-normal incidence, large dislocation loops with a range of Burgers vectors are formed. Further glancing incidence FIB polishing with 5 keV ion energy removes these dislocation loops and reduces the lattice strains caused by higher energy FIB milling. However, even at the lower ion energy, damage-induced lattice strains are present within a ~20 nm thick surface layer. These results highlight the need for careful consideration and management of FIB damage. They also show that low-energy FIB-milling is an effective tool for removing FIB-milling induced lattice strains. This is important for the preparation of micro-mechanical test specimens and strain microscopy samples.« less

Glancing-incidence focussed ion beam milling: A coherent X-ray diffraction study of 3D nano-scale lattice strains and crystal defects

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

Hofmann, Felix; Harder, Ross J.; Liu, Wenjun

Here, this study presents a detailed examination of the lattice distortions introduced by glancing incidence Focussed Ion Beam (FIB) milling. Using non-destructive multi-reflection Bragg coherent X-ray diffraction we probe damage formation in an initially pristine gold micro-crystal following several stages of FIB milling. These experiments allow access to the full lattice strain tensor in the micro-crystal with ~25 nm 3D spatial resolution, enabling a nano-scale analysis of residual lattice strains and defects formed. Our results show that 30 keV glancing incidence milling produces fewer large defects than normal incidence milling at the same energy. However the resulting residual lattice strainsmore » have similar magnitude and extend up to ~50 nm into the sample. At the edges of the milled surface, where the ion-beam tails impact the sample at near-normal incidence, large dislocation loops with a range of Burgers vectors are formed. Further glancing incidence FIB polishing with 5 keV ion energy removes these dislocation loops and reduces the lattice strains caused by higher energy FIB milling. However, even at the lower ion energy, damage-induced lattice strains are present within a ~20 nm thick surface layer. These results highlight the need for careful consideration and management of FIB damage. They also show that low-energy FIB-milling is an effective tool for removing FIB-milling induced lattice strains. This is important for the preparation of micro-mechanical test specimens and strain microscopy samples.« less

Selenium single-wavelength anomalous diffraction de novo phasing using an X-ray-free electron laser

DOE PAGES

Hunter, Mark S.; Yoon, Chun Hong; DeMirci, Hasan; ...

2016-11-04

Structural information about biological macromolecules near the atomic scale provides important insight into the functions of these molecules. To date, X-ray crystallography has been the predominant method used for macromolecular structure determination. However, challenges exist when solving structures with X-rays, including the phase problem and radiation damage. X-ray-free electron lasers (X-ray FELs) have enabled collection of diffraction information before the onset of radiation damage, yet the majority of structures solved at X-ray FELs have been phased using external information via molecular replacement. De novo phasing at X-ray FELs has proven challenging due in part to per-pulse variations in intensity andmore » wavelength. Here we report the solution of a selenobiotinyl-streptavidin structure using phases obtained by the anomalous diffraction of selenium measured at a single wavelength (Se-SAD) at the Linac Coherent Light Source. Finally, our results demonstrate Se-SAD, routinely employed at synchrotrons for novel structure determination, is now possible at X-ray FELs.« less

Macromolecular structures probed by combining single-shot free-electron laser diffraction with synchrotron coherent X-ray imaging.

PubMed

Gallagher-Jones, Marcus; Bessho, Yoshitaka; Kim, Sunam; Park, Jaehyun; Kim, Sangsoo; Nam, Daewoong; Kim, Chan; Kim, Yoonhee; Noh, Do Young; Miyashita, Osamu; Tama, Florence; Joti, Yasumasa; Kameshima, Takashi; Hatsui, Takaki; Tono, Kensuke; Kohmura, Yoshiki; Yabashi, Makina; Hasnain, S Samar; Ishikawa, Tetsuya; Song, Changyong

2014-05-02

Nanostructures formed from biological macromolecular complexes utilizing the self-assembly properties of smaller building blocks such as DNA and RNA hold promise for many applications, including sensing and drug delivery. New tools are required for their structural characterization. Intense, femtosecond X-ray pulses from X-ray free-electron lasers enable single-shot imaging allowing for instantaneous views of nanostructures at ambient temperatures. When combined judiciously with synchrotron X-rays of a complimentary nature, suitable for observing steady-state features, it is possible to perform ab initio structural investigation. Here we demonstrate a successful combination of femtosecond X-ray single-shot diffraction with an X-ray free-electron laser and coherent diffraction imaging with synchrotron X-rays to provide an insight into the nanostructure formation of a biological macromolecular complex: RNA interference microsponges. This newly introduced multimodal analysis with coherent X-rays can be applied to unveil nano-scale structural motifs from functional nanomaterials or biological nanocomplexes, without requiring a priori knowledge.

Improved electrochemical properties of a coin cell using LiMn 1.5Ni 0.5O 4 as cathode in the 5 V range

NASA Astrophysics Data System (ADS)

Singhal, Rahul; Das, Suprem R.; Oviedo, Osbert; Tomar, Maharaj S.; Katiyar, Ram S.

Phase pure LiMn 1.5Ni 0.5O 4 powders were synthesized by a chemical synthesis route and were subsequently characterized as cathode materials in a Li-ion coin cell comprising a Li anode and lithium hexafluorophosphate (LiPF 6), dissolved in dimethyl carbonate (DMC) + ethylene carbonate (EC) [1:1, v/v ratio] as electrolyte. The spinel structure and phase purity of the powders were characterized using X-ray diffraction and micro-Raman spectroscopy. The presence of both oxidation and reduction peaks in the cyclic voltammogram revealed Li + extraction and insertion from the spinel structure. The charge-discharge characteristics of the coin cell were performed in the 3.0-4.8 V range. An initial discharge capacity of ∼140 mAh g -1 was obtained with 94% initial discharge capacity retention after 50 repeated cycles. The microstructures and compositions of the cathode before and after electrochemistry were investigated using scanning electron microscopy and energy-dispersive analysis by X-ray analysis, respectively. Using X-ray diffraction, Raman spectroscopy and electrochemical analysis, we correlated the structural stability and the electrochemical performance of this cathode.

Reaction of Pb(II) and Zn(II) with Ethyl Linoleate To Form Structured Hybrid Inorganic–Organic Complexes: A Model for Degradation in Historic Paint Films

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

MacDonald, Margaret G.; Palmer, Michael R.; Suchomel, Matthew R.

To investigate soap formation in drying oils in historic paints, the reaction between metal acetates (K +, Zn 2+, Pb 2+) and ethyl linoleate (EL) was studied using optical microscopy, X-ray powder diffraction, and electron microscopy. Pb(II) and Zn(II) react rapidly with EL to form highly structured, spherulitic, luminescent crystallites that aggregate. Evidence from Fourier transform infrared (FTIR) and scanning electron microscopy/energy dispersive X-ray analysis and high-resolution synchrotron powder X-ray diffraction indicates that these are organic-inorganic hybrid complexes or coordination polymers. FTIR absorbance peaks at ca. 1540 cm -1 for Pb(II) and ca. 1580 cm -1 for Zn(II) are consistentmore » with the formation of carboxylate complexes. The complexes formed offer insight into the degradation processes observed in oil paint films, suggesting that soap formation is rapid when metal ions are solubilized and can occur with unsaturated fatty acids that are present in fresh oils. Finally, these complexes may account for the atypical luminescence observed in lead-containing cured oil paint films.« less

Reaction of Pb(II) and Zn(II) with Ethyl Linoleate To Form Structured Hybrid Inorganic–Organic Complexes: A Model for Degradation in Historic Paint Films

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

MacDonald, Margaret G.; Palmer, Michael R.; Suchomel, Matthew R.

To investigate soap formation in drying oils in historic paints, the reaction between metal acetates (K +, Zn 2+, Pb 2+) and ethyl linoleate (EL) was studied using optical microscopy, X-ray powder diffraction, and electron microscopy. Pb(II) and Zn(II) react rapidly with EL to form highly structured, spherulitic, luminescent crystallites that aggregate. Evidence from Fourier transform infrared (FTIR) and scanning electron microscopy/energy dispersive X-ray analysis and high-resolution synchrotron powder X-ray diffraction indicates that these are organic–inorganic hybrid complexes or coordination polymers. FTIR absorbance peaks at ca. 1540 cm –1 for Pb(II) and ca. 1580 cm –1 for Zn(II) are consistentmore » with the formation of carboxylate complexes. The complexes formed offer insight into the degradation processes observed in oil paint films, suggesting that soap formation is rapid when metal ions are solubilized and can occur with unsaturated fatty acids that are present in fresh oils. These complexes may account for the atypical luminescence observed in lead-containing cured oil paint films.« less

Reaction of Pb(II) and Zn(II) with Ethyl Linoleate To Form Structured Hybrid Inorganic–Organic Complexes: A Model for Degradation in Historic Paint Films

DOE PAGES

MacDonald, Margaret G.; Palmer, Michael R.; Suchomel, Matthew R.; ...

2016-09-07

To investigate soap formation in drying oils in historic paints, the reaction between metal acetates (K +, Zn 2+, Pb 2+) and ethyl linoleate (EL) was studied using optical microscopy, X-ray powder diffraction, and electron microscopy. Pb(II) and Zn(II) react rapidly with EL to form highly structured, spherulitic, luminescent crystallites that aggregate. Evidence from Fourier transform infrared (FTIR) and scanning electron microscopy/energy dispersive X-ray analysis and high-resolution synchrotron powder X-ray diffraction indicates that these are organic-inorganic hybrid complexes or coordination polymers. FTIR absorbance peaks at ca. 1540 cm -1 for Pb(II) and ca. 1580 cm -1 for Zn(II) are consistentmore » with the formation of carboxylate complexes. The complexes formed offer insight into the degradation processes observed in oil paint films, suggesting that soap formation is rapid when metal ions are solubilized and can occur with unsaturated fatty acids that are present in fresh oils. Finally, these complexes may account for the atypical luminescence observed in lead-containing cured oil paint films.« less

Thermolysis synthesis of pure phase NiO from novel sonochemical synthesized Ni(II) nano metal-organic supramolecular architecture.

PubMed

Hanifehpour, Younes; Morsali, Ali; Mirtamizdoust, Babak; Joo, Sang Woo; Soltani, Behzad

2017-07-01

Nano-structures of a new supramolecular coordination compound of divalent nickel with the pyrazol (pzH) containing the terminal azide anions, [Ni(pzH) 2 (N 3 ) 2 ] (1), with discrete molecular architecture (DMA) in solid state was synthesized via sonochemical method. The new nanostructure was characterized by scanning electron microscopy, X-ray powder diffraction, IR, and elemental analysis. Compound 1 was structurally characterized by single crystal X-ray diffraction and the single-crystal X-ray data shows that the coordination number of Ni (II) ions is six, (NiN 6 ), with four N-donor atoms from neutral "pzH" ligands and two N-donors from two terminal azide anions. The supramolecular features in these complexes are guided and controlled by weak directional intermolecular interactions. The structure of the title complex was optimized by density functional theory calculations. Calculated structural parameters and IR spectra for the title complex are consistent with the crystal structure. The NiO nanoparticles were obtained by thermolysis of 1 at 180°C with oleic acid as a surfactant. Copyright © 2017 Elsevier B.V. All rights reserved.

Exploration of New Principles in Spintronics Based on Topological Insulators (Option 1)

DTIC Science & Technology

2012-05-14

on the surface and found that our crystals are exceedingly homogeneous (Supplementary Information). The persistently narrow X - ray diffraction peaks...modified Bridgman method (see Supplementary Information for details). X - ray diffraction measurements indicated the monotonic shrinkage of a and c axis...and annealing at that temperature for 4 days. X - ray diffraction analyses confirmed that all the samples have the same crystal structure (R 3m

Efficient modeling of Bragg coherent x-ray nanobeam diffraction

DOE PAGES

Hruszkewycz, S. O.; Holt, M. V.; Allain, M.; ...

2015-07-02

X-ray Bragg diffraction experiments that utilize tightly focused coherent beams produce complicated Bragg diffraction patterns that depend on scattering geometry, characteristics of the sample, and properties of the x-ray focusing optic. In this paper, we use a Fourier-transform-based method of modeling the 2D intensity distribution of a Bragg peak and apply it to the case of thin films illuminated with a Fresnel zone plate in three different Bragg scattering geometries. Finally, the calculations agree well with experimental coherent diffraction patterns, demonstrating that nanodiffraction patterns can be modeled at nonsymmetric Bragg conditions with this approach—a capability critical for advancing nanofocused x-raymore » diffraction microscopy.« less

Synthesis and characterization of montmorillonite clay intercalated with molecular magnetic compounds

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

Martins, Marcel G.; Martins, Daniel O.T.A.; Carvalho, Beatriz L.C. de

2015-08-15

In this work montmorillonite (MMT) clay, whose matrix was modified with an ammonium salt (hexadecyltrimethylammonium bromide – CTAB), was employed as an inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange: a nitronyl nitroxide derivative 2-[4-(N-ethyl)-pyridinium]-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (p-EtRad{sup +}) and two binuclear coordination compounds, [Ni(valpn)Ln]{sup 3+}, where H{sub 2}valpn stands for 1,3-propanediyl-bis(2-iminomethylene-6-methoxy-phenol), and Ln=Gd{sup III}; Dy{sup III}. The pristine MMT and the intercalated materials were characterized by X-ray powder diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and magnetic measurements. The X-ray diffraction data analysis showed an increase of the interlamellar spacemore » of the intercalated MMT, indicating the intercalation of the magnetic compounds. Furthermore, the magnetic properties of the hybrid compounds were investigated, showing similar behavior as the pure magnetic guest species. - Graphical abstract: Montmorillonite clay was employed as inorganic host for the intercalation of three different molecular magnetic compounds through ion exchange - Highlights: • Montmorillonite was employed as a host material. • Three molecular magnetic compounds were intercalated through ion exchange. • The compounds were successful intercalated maintaining the layered structure. • The hybrid materials exhibited similar magnetic behavior as the pure magnetic guest.« less

Diketonylpyridinium Cations as a Support of New Ionic Liquid Crystals and Ion-Conductive Materials: Analysis of Counter-Ion Effects.

PubMed

Pastor, María Jesús; Cuerva, Cristián; Campo, José A; Schmidt, Rainer; Torres, María Rosario; Cano, Mercedes

2016-05-12

Ionic liquid crystals (ILCs) allow the combination of the high ionic conductivity of ionic liquids (ILs) with the supramolecular organization of liquid crystals (LCs). ILCs salts were obtained by the assembly of long-chained diketonylpyridinium cations of the type [HOO R(n)pyH ]⁺ and BF₄ - , ReO₄ - , NO₃ - , CF₃SO₃ - , CuCl₄ 2- counter-ions. We have studied the thermal behavior of five series of compounds by differential scanning calorimetry (DSC) and hot stage polarized light optical microscopy (POM). All materials show thermotropic mesomorphism as well as crystalline polymorphism. X-ray diffraction of the [HOO R(12)pyH ][ReO₄] crystal reveals a layered structure with alternating polar and apolar sublayers. The mesophases also exhibit a lamellar arrangement detected by variable temperature powder X-ray diffraction. The CuCl₄ 2- salts exhibit the best LC properties followed by the ReO₄ - ones due to low melting temperature and wide range of existence. The conductivity was probed for the mesophases in one species each from the ReO₄ - , and CuCl₄ 2- families, and for the solid phase in one of the non-mesomorphic Cl - salts. The highest ionic conductivity was found for the smectic mesophase of the ReO₄ - containing salt, whereas the solid phases of all salts were dominated by electronic contributions. The ionic conductivity may be favored by the mesophase lamellar structure.

Local geometric and electronic structures and origin of magnetism in Co-doped BaTiO3 multiferroics

NASA Astrophysics Data System (ADS)

Phan, The-Long; Thang, P. D.; Ho, T. A.; Manh, T. V.; Thanh, Tran Dang; Lam, V. D.; Dang, N. T.; Yu, S. C.

2015-05-01

We have prepared polycrystalline samples BaTi1-xCoxO3 (x = 0-0.1) by solid-state reaction. X-ray diffraction and Raman-scattering studies reveal the phase separation in crystal structure as changing Co-doping content (x). The samples with x = 0-0.01 are single phase in a tetragonal structure. At higher doping contents (x > 0.01), there is the formation and development of a secondary hexagonal phase. Magnetization measurements at room temperature indicate a coexistence of paramagnetic and weak-ferromagnetic behaviors in BaTi1-xCoxO3 samples with x > 0, while pure BaTiO3 is diamagnetic. Both these properties increase with increasing x. Analyses of X-ray absorption spectra recorded from BaTi1-xCoxO3 for the Co and Ti K-edges indicate the presence of Co2+ and Co3+ ions. They locate in the Ti4+ site of the tetragonal and hexagonal BaTiO3 structures. Particularly, there is a shift of oxidation state from Co2+ to Co3+ when Co-doping content increases. We believe that the paramagnetic nature in BaTi1-xCoxO3 samples is due to isolated Co2+ and Co3+ centers. The addition of Co3+ ions enhances the paramagnetic behavior. Meanwhile, the origin of ferromagnetism is due to lattice defects, which is less influenced by the changes caused by the variation in concentration of Co2+ and Co3+ ions.

HiSPoD: a program for high-speed polychromatic X-ray diffraction experiments and data analysis on polycrystalline samples

DOE PAGES

Sun, Tao; Fezzaa, Kamel

2016-06-17

Here, a high-speed X-ray diffraction technique was recently developed at the 32-ID-B beamline of the Advanced Photon Source for studying highly dynamic, yet non-repeatable and irreversible, materials processes. In experiments, the microstructure evolution in a single material event is probed by recording a series of diffraction patterns with extremely short exposure time and high frame rate. Owing to the limited flux in a short pulse and the polychromatic nature of the incident X-rays, analysis of the diffraction data is challenging. Here, HiSPoD, a stand-alone Matlab-based software for analyzing the polychromatic X-ray diffraction data from polycrystalline samples, is described. With HiSPoD,more » researchers are able to perform diffraction peak indexing, extraction of one-dimensional intensity profiles by integrating a two-dimensional diffraction pattern, and, more importantly, quantitative numerical simulations to obtain precise sample structure information.« less

Uniform Fe3O4 microflowers hierarchical structures assembled with porous nanoplates as superior anode materials for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Wang, Xiaoliang; Liu, Yanguo; Arandiyan, Hamidreza; Yang, Hongping; Bai, Lu; Mujtaba, Jawayria; Wang, Qingguo; Liu, Shanghe; Sun, Hongyu

2016-12-01

Uniform Fe3O4 microflowers assembled with porous nanoplates were successfully synthesized by a solvothermal method and subsequent annealing process. The structural and compositional analysis of the Fe3O4 microflowers were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The Bruauer-Emmett-Teller (BET) specific surface area was calculated by the nitrogen isotherm curve and pore size distribution of Fe3O4 microflowers was determined by the Barret-Joyner-Halenda (BJH) method. When evaluated as anode material for lithium-ion batteries, the as-prepared Fe3O4 microflowers electrodes delivered superior capacity, better cycling stability and rate capability than that of Fe3O4 microspheres electrodes. The improved electrochemical performance was attributed to the microscale flowerlike architecture and the porous sheet structural nature.

Study of chloride ion transport of composite by using cement and starch as a binder

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

Armynah, Bidayatul; Halide, Halmar; Zahrawani,

This study presents the chemical bonding and the structural properties of composites from accelerator chloride test migration (ACTM). The volume fractions between binder (cement and starch) and charcoal in composites are 20:80 and 60:40. The effect of the binder to the chemical composition, chemical bonding, and structural properties before and after chloride ion passing through the composites was determined by X-ray fluorescence (XRF), by Fourier transform infra-red (FTIR), and x-ray diffraction (XRD), respectively. From the XRD data, XRF data, and the FTIR data shows the amount of chemical composition, the type of binding, and the structure of composites are dependingmore » on the type of binder. The amount of chloride migration using starch as binder is higher than that of cement as a binder due to the density effects.« less

The use of Co2+ for crystallization and structure determination, using a conventional mono­chromatic X-ray source, of flax rust avirulence protein

PubMed Central

Gunčar, Gregor; Wang, Ching-I A.; Forwood, Jade K.; Teh, Trazel; Catanzariti, Ann-Maree; Ellis, Jeffrey G.; Dodds, Peter N.; Kobe, Boštjan

2007-01-01

Metal-binding sites are ubiquitous in proteins and can be readily utilized for phasing. It is shown that a protein crystal structure can be solved using single-wavelength anomalous diffraction based on the anomalous signal of a cobalt ion measured on a conventional monochromatic X-ray source. The unique absorption edge of cobalt (1.61 Å) is compatible with the Cu Kα wavelength (1.54 Å) commonly available in macromolecular crystallography laboratories. This approach was applied to the determination of the structure of Melampsora lini avirulence protein AvrL567-A, a protein with a novel fold from the fungal pathogen flax rust that induces plant disease resistance in flax plants. This approach using cobalt ions may be applicable to all cobalt-binding proteins and may be advantageous when synchrotron radiation is not readily available. PMID:17329816

Structure and properties of TiSiCN coatings with different bias voltages by arc ion plating

NASA Astrophysics Data System (ADS)

Xie, Xinming; Li, Jinlong; Dong, Minpeng; Zhang, Henghua; Wang, Liping

2018-03-01

TiSiCN coatings were deposited on 316 L steel using the multi-arc ion plating system. All the coatings had the same total thickness of approximately 1.6 µm. The TiSiCN coatings were deposited under the mixture constant flow of N2 and C2H2 but varying bias. Information about structures, composition and properties were characterized by scanning electron microscope, x-ray diffraction, x-ray photoelectron spectroscopy, nanoindentation and ball-on-plate wear tests. The results show that all of the coatings consist of a TiCN nano-crystal phase and an Si3N4 amorphous phase. With an increase in the bias, the film becomes denser and exhibits better tribological behavior and mechanical properties. Moreover, the bonding strength between the coatings and the substrate increased and the resistance to thermal shock intensified when the coatings were made at a higher bias voltage.

X-ray diffraction and X-ray standing-wave study of the lead stearate film structure

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

Blagov, A. E.; Dyakova, Yu. A.; Kovalchuk, M. V.

2016-05-15

A new approach to the study of the structural quality of crystals is proposed. It is based on the use of X-ray standing-wave method without measuring secondary processes and considers the multiwave interaction of diffraction reflections corresponding to different harmonics of the same crystallographic reflection. A theory of multiwave X-ray diffraction is developed to calculate the rocking curves in the X-ray diffraction scheme under consideration for a long-period quasi-one-dimensional crystal. This phase-sensitive method is used to study the structure of a multilayer lead stearate film on a silicon substrate. Some specific structural features are revealed for the surface layer ofmore » the thin film, which are most likely due to the tilt of the upper layer molecules with respect to the external normal to the film surface.« less

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.

High-resolution ab initio three-dimensional x-ray diffraction microscopy

DOE PAGES

Chapman, Henry N.; Barty, Anton; Marchesini, Stefano; ...

2006-01-01

Coherent x-ray diffraction microscopy is a method of imaging nonperiodic isolated objects at resolutions limited, in principle, by only the wavelength and largest scattering angles recorded. We demonstrate x-ray diffraction imaging with high resolution in all three dimensions, as determined by a quantitative analysis of the reconstructed volume images. These images are retrieved from the three-dimensional diffraction data using no a priori knowledge about the shape or composition of the object, which has never before been demonstrated on a nonperiodic object. We also construct two-dimensional images of thick objects with greatly increased depth of focus (without loss of transverse spatialmore » resolution). These methods can be used to image biological and materials science samples at high resolution with x-ray undulator radiation and establishes the techniques to be used in atomic-resolution ultrafast imaging at x-ray free-electron laser sources.« less

Enhancing resolution in coherent x-ray diffraction imaging.

PubMed

Noh, Do Young; Kim, Chan; Kim, Yoonhee; Song, Changyong

2016-12-14

Achieving a resolution near 1 nm is a critical issue in coherent x-ray diffraction imaging (CDI) for applications in materials and biology. Albeit with various advantages of CDI based on synchrotrons and newly developed x-ray free electron lasers, its applications would be limited without improving resolution well below 10 nm. Here, we review the issues and efforts in improving CDI resolution including various methods for resolution determination. Enhancing diffraction signal at large diffraction angles, with the aid of interference between neighboring strong scatterers or templates, is reviewed and discussed in terms of increasing signal-to-noise ratio. In addition, we discuss errors in image reconstruction algorithms-caused by the discreteness of the Fourier transformations involved-which degrade the spatial resolution, and suggest ways to correct them. We expect this review to be useful for applications of CDI in imaging weakly scattering soft matters using coherent x-ray sources including x-ray free electron lasers.

A portable X-ray diffraction apparatus for in situ analyses of masters' paintings

NASA Astrophysics Data System (ADS)

Eveno, Myriam; Duran, Adrian; Castaing, Jacques

2010-09-01

It is rare that the analyses of materials in paintings can be carried out by taking micro-samples. Valuable works of art are best studied in situ by non-invasive techniques. For that purpose, a portable X-ray diffraction and fluorescence apparatus has been designed and constructed at the C2RMF. This apparatus has been used for paintings of Rembrandt, Leonardo da Vinci, Van Gogh, Mantegna, etc. Results are given to illustrate the performance of X-ray diffraction, especially when X-ray fluorescence does not bring sufficient information to conclude.

Investigations on Cu2+-substituted Ni-Zn ferrite nanoparticles

NASA Astrophysics Data System (ADS)

Amarjeet; Kumar, Vinod

2016-11-01

CuxNi(1-x)/2Zn(1-x)/2Fe2O4 (x = 0.1, 0.3 and 0.5) nanoparticles were prepared by chemical co-precipitation method. The developed nanoparticles were characterized for structural properties by powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) techniques. Peak position in the X-ray diffraction pattern confirmed the single spinel phase of the developed particles. Infrared (IR) spectroscopy in mid-IR range showed the presence of characteristic absorption bands corresponding to octahedral and tetrahedral bonds in the spinel structure of prepared samples. Thermo-gravimetric analysis (TGA) measurements showed a considerable weight loss in the developed samples above 700∘C. Frequency dependence of the electrical properties of the developed material pellets was studied in the frequency range of 1 kHz-5 MHz. Temperature dependence of the dielectric constant of Cu0.1Ni0.45Zn0.45Fe2O4 was studied at different temperatures, i.e. at 425, 450 and 475 K, in the frequency range of 1 kHz-5 MHz. It was found that the electrical conductivity decreases with increasing Cu2+ ion content while it increases with the increase in temperature.

Study of the structure and ferroelectric behavior of BaBi4-xLaxTi4O15 ceramics

NASA Astrophysics Data System (ADS)

Khokhar, Anita; Goyal, Parveen K.; Thakur, O. P.; Sreenivas, K.

2015-06-01

The structure and ferroelectric properties of Lanthanum substituted barium bismuth titanate BaBi4-xLaxTi4O15 (0 ≤ x ≤ 0.5) ceramics prepared by solid-state reaction method have been investigated. X-ray diffraction (XRD) confirms the formation of a single phase material. The distribution of lanthanum into the perovskite layers and (Bi2O2)2+ layers of BaBi4Ti4O15 ceramics have been revealed through Raman spectroscopy. At lower value of x, it is seen that La3+ ions prefer to substitute A-site Bi3+ ions in the perovskite layers while for higher x values, La3+ ions get incorporated into the (Bi2O2)2+ layers. A critical La content of x ˜ 0.2 in BaBi4-xLaxTi4O15 is seen to exhibit a large remnant polarization (Pr) with low coercive field (Ec). The improvement in the ferroelectric properties of La substituted BaBi4Ti4O15 ceramics has been explained in terms of changing oxygen vacancy concentration and structural relaxation. Tunable ferroelectric materials can be obtained by manipulating the doping amount of lanthanum ion.

LiAl xCo 1- xO 2 as 4 V cathodes for lithium ion batteries

NASA Astrophysics Data System (ADS)

Huang, Haitao; Rao, G. V. Subba; Chowdari, B. V. R.

Nominal LiAl xCo 1- xO 2 with x ranging from 0.1 to 0.3 was prepared by heating mixture of Al(OH) 3, Co 3O 4 and LiOH at 750°C in air. The effect of substitution of non-transition metal, Al, in LiCoO 2 is investigated as a 4 V cathode for lithium ion. X-ray diffraction (XRD) indicates formation of a single phase (R3¯m) within this range of substitution. When cycled between 4.5 and 2.5 V vs. Li/Li + at a current density of 1 mA cm -2, the LiAl 0.15Co 0.85O 2 cathode exhibits reversible capacity of 160 mA h g -1 initially. XRD of the cathode made at the end of 10 cycles reveals no significant change on host structure.

X-ray fractography on fatigue fractured surface of austenitic stainless steel

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

Yajima, Zenjiro; Tokuyama, Hideki; Kibayashi, Yasuo

1995-12-31

X-ray diffraction observation of the material internal structure beneath fracture surfaces provide fracture analysis with useful information to investigate the conditions and mechanisms of fracture. X-ray fractography is a generic name given to this technique. In the present study, X-ray fractography was applied to fatigue fracture surfaces of austenitic stainless steel (AISI 304) which consisted of solution treatment. The fatigue tests were carried out on compact tension (CT) specimens. The plastic strain on the fracture surface was estimated from measuring the line broadening of X-ray diffraction profiles. The line broadening of X-ray diffraction profiles was measured on and beneath fatiguemore » fracture surfaces. The depth of the plastic zone left on fracture surfaces was evaluated from the line broadening. The results are discussed on the basis of fracture mechanics.« less

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.

Diffraction and Imaging Study of Imperfections of Protein Crystals with Coherent X-rays

NASA Technical Reports Server (NTRS)

Hu, Z. W.; Thomas, B. R.; Chernov, A. A.; Chu, Y. S.; Lai, B.

2004-01-01

High angular-resolution x-ray diffraction and phase contrast x-ray imaging were combined to study defects and perfection of protein crystals. Imperfections including line defects, inclusions and other microdefects were observed in the diffraction images of a uniformly grown lysozyme crystal. The observed line defects carry distinct dislocation features running approximately along the <110> growth front and have been found to originate mostly in a central growth area and occasionally in outer growth regions. Slow dehydration led to the broadening of a fairly symmetric 4 4 0 rocking curve by a factor of approximately 2.6, which was primarily attributed to the dehydration-induced microscopic effects that are clearly shown in diffraction images. X-ray imaging and diffraction characterization of the quality of apoferritin crystals will also be discussed in the presentation.

Ion beam sputtering of fluoropolymers

NASA Technical Reports Server (NTRS)

Sovey, J. S.

1978-01-01

Etching and deposition of fluoropolymers are of considerable industrial interest for applications dealing with adhesion, chemical inertness, hydrophobicity, and dielectric properties. This paper describes ion beam sputter processing rates as well as pertinent characteristics of etched targets and films. An argon ion beam source was used to sputter etch and deposit the fluoropolymers PTFE, FEP, and CTFE. Ion beam energy, current density, and target temperature were varied to examine effects on etch and deposition rates. The ion etched fluoropolymers yield cone or spire-like surface structures which vary depending upon the type of polymer, ion beam power density, etch time, and target temperature. Also presented are sputter target and film characteristics which were documented by spectral transmittance measurements, X-ray diffraction, ESCA, and SEM photomicrographs.

Swift heavy ion induced modification in morphological and physico-chemical properties of tin oxide nanocomposites

NASA Astrophysics Data System (ADS)

Jaiswal, Manoj Kumar; Kanjilal, D.; Kumar, Rajesh

2013-11-01

Nanocomposite thin films of tin oxide (SnO2)/titanium oxide (TiO2) were grown on silicon (1 0 0) substrates by electron beam evaporation deposition technique using sintered nanocomposite pellet of SnO2/TiO2 in the percentage ratio of 95:5. Sintering of the nanocomposite pellet was done at 1300 °C for 24 h. The thicknesses of these films were measured to be 100 nm during deposition using piezo-sensor attached to the deposition chamber. TiO2 doped SnO2 nanocomposite films were irradiated by 100 MeV Au8+ ion beam at fluence range varying from 1 × 1011 ions/cm2 to 5 × 1013 ions/cm2 at Inter University Accelerator Center (IUAC), New Delhi, India. Chemical properties of pristine and ion irradiation modified thin films were characterized by Fourier Transform Infrared (FTIR) spectroscopy. FTIR peak at 610 cm-1 confirms the presence of O-Sn-O bridge of tin (IV) oxide signifying the composite nature of pristine and irradiated thin films. Atomic Force Microscope (AFM) in tapping mode was used to study the surface morphology and grain growth due to swift heavy ion irradiation at different fluencies. Grain size calculations obtained from sectional analysis of AFM images were compared with results obtained from Glancing Angle X-ray Diffraction (GAXRD) measurements using Scherrer’s formulae. Phase transformation due to irradiation was observed from Glancing Angle X-ray Diffraction (GAXRD) results. The prominent 2θ peaks observed in GAXRD spectrum are at 30.67°, 32.08°, 43.91°, 44.91° and 52.35° in the irradiated films.

THE EFFECT OF SATELLITE LINES FROM THE X-RAY SOURCE ON X-RAY DIFFRACTION PEAKS

EPA Science Inventory

The article discusses the development of a method for relating reactivity to crystallite size and strain parameters obtained by the Warren-Averbach technique. EPA has been using crystallite size and strain data obtained from x-ray diffraction (XRD) peak profile analysis to predic...

History and Solution of the Phase Problem in theTheory of Structure Determination of Crystals from X-ray Diffraction Experiments

ScienceCinema

Wolf, Emil [University of Rochester, Rochester, New York, United States

2017-12-09

Since the pioneering work of Max von Laue on interference and diffraction of x-rays, carried out almost 100 years ago, numerous attempts have been made to determine structures of crystalline media from x-ray diffraction experiments. The usefulness of all of them has been limited by the inability of measuring phases of the diffracted beams. In this talk, the most important research carried out in this field will be reviewed and a recently obtained solution of the phase problem will be presented.

Structural and electrochemical study of positive electrode materials for rechargeable lithium ion batteries

NASA Astrophysics Data System (ADS)

Jiang, Meng

The research presented in this dissertation focuses on a combined study of the electrochemistry and the structure of positive electrode materials for Li ion batteries. Li ion batteries are one of the most advanced energy storage systems and have been the subject of numerous scientific studies in recent decades. They have been widely used for various mobile devices such as cell phones, laptop computers and power tools. They are also promising candidates as power sources for automotive applications. Although intensive research has been done to improve the performance of Li ion batteries, there are still many remaining challenges to overcome so that they can be used in a wider range of applications. In particular, cheaper and safer electrodes are required with much higher reversible capacity. The series of layered nickel manganese oxides [NixLi 1/3-2x/3Mn2/3- x/3]O2 (0 < x < 1/2) are promising alternatives for Li2CoO2, the commercial positive electrode materials in Li ion batteries, because of their lower cost and higher safety and abuse tolerance, when lithium is removed from their structure. Compounds with x<1/2, in which the total Li content is higher than transition metal content, are referred as "Li-excess" materials. The "Li2MnO3-like" region is always present in this type of materials, and the overcapacity is obtained in the first charge process, which is not reversible in the following cycles. A combined X-ray diffraction, solid state nuclear magnetic resonance and X-ray absorption spectroscopy study is performed to investigate the effect of synthetic methods on the structure, to probe the structural change of the materials during cycling and to understand the electrochemical reaction mechanism. The conversion compounds are also investigated because of their high capacities. Since the various compounds have different voltage windows, they can have potential applications as both cathodes and anodes. Solid state nuclear magnetic resonance is used to study the change in the local environment of the structure during the cycling process. Two systems are included in this work, including iron fluorides and Cu-containing materials. A comparison study has been performed on FeF3 and FeF2. Different discharge reaction mechanisms are clarified for each compound, and possible phase transitions are proposed as well. As for the Cu-containing systems, three compounds were chosen with different anions: CuS, CuO and CuF2. The reaction mechanisms are studied by 63Cu, 7Li and 19F NMR and supported by powder X-ray diffraction.

Two-Step Adsorption of PtCl 6 2– Complexes at a Charged Langmuir Monolayer: Role of Hydration and Ion Correlations

DOE PAGES

Uysal, Ahmet; Rock, William; Qiao, Baofu; ...

2017-11-03

Anion exchange at positively charged interfaces plays an important role in a variety of physical and chemical processes. However, the molecular-scale details of these processes, especially with heavy and large anionic complexes, are not well-understood. Here, we studied the adsorption of PtCl 6 2– anionic complexes to floating DPTAP monolayers in the presence of excess Cl– as a function of the bulk chlorometalate concentration. This system aims to simulate the industrial conditions for heavy metal separations with solvent extraction. In situ X-ray scattering and fluorescence measurements, which are element and depth sensitive, show that the chlorometalate ions only adsorb inmore » the diffuse layer at lower concentrations, while they adsorb predominantly in the Stern layer at higher concentrations. The response of DPTAP molecules to the adsorbed ions is determined independently by grazing incidence X-ray diffraction and supports this picture. Molecular dynamics simulations further elucidate the nanoscale structure of the interfacial complexes. The results suggest that ion hydration and ion–ion correlations play a key role in the competitive adsorption process.« less

XRayView: a teaching aid for X-ray crystallography.

PubMed

Phillips, G N

1995-10-01

A software package, XRayView, has been developed that uses interactive computer graphics to introduce basic concepts of x-ray diffraction by crystals, including the reciprocal lattice, the Ewald sphere construction, Laue cones, the wavelength dependence of the reciprocal lattice, primitive and centered lattices and systematic extinctions, rotation photography. Laue photography, space group determination and Laue group symmetry, and the alignment of crystals by examination of reciprocal space. XRayView is designed with "user-friendliness" in mind, using pull-down menus to control the program. Many of the experiences of using real x-ray diffraction equipment to examine crystalline diffraction can be simulated. Exercises are available on-line to guide the users through many typical x-ray diffraction experiments.

Application of MEMS-based x-ray optics as tuneable nanosecond choppers

NASA Astrophysics Data System (ADS)

Chen, Pice; Walko, Donald A.; Jung, Il Woong; Li, Zhilong; Gao, Ya; Shenoy, Gopal K.; Lopez, Daniel; Wang, Jin

2017-08-01

Time-resolved synchrotron x-ray measurements often rely on using a mechanical chopper to isolate a set of x-ray pulses. We have started the development of micro electromechanical systems (MEMS)-based x-ray optics, as an alternate method to manipulate x-ray beams. In the application of x-ray pulse isolation, we recently achieved a pulse-picking time window of half a nanosecond, which is more than 100 times faster than mechanical choppers can achieve. The MEMS device consists of a comb-drive silicon micromirror, designed for efficiently diffracting an x-ray beam during oscillation. The MEMS devices were operated in Bragg geometry and their oscillation was synchronized to x-ray pulses, with a frequency matching subharmonics of the cycling frequency of x-ray pulses. The microscale structure of the silicon mirror in terms of the curvature and the quality of crystallinity ensures a narrow angular spread of the Bragg reflection. With the discussion of factors determining the diffractive time window, this report showed our approaches to narrow down the time window to half a nanosecond. The short diffractive time window will allow us to select single x-ray pulse out of a train of pulses from synchrotron radiation facilities.

Fabrication of high-resolution x-ray diffractive optics at King's College London

NASA Astrophysics Data System (ADS)

Charalambous, Pambos S.; Anastasi, Peter A. F.; Burge, Ronald E.; Popova, Katia

1995-09-01

The fabrication of high resolution x-ray diffractive optics, and Fresnel zone plates (ZPs) in particular, is a very demanding multifaceted technological task. The commissioning of more (and brighter) synchrotron radiation sources, has increased the number of x-ray imaging beam lines world wide. The availability of cheaper and more effective laboratory x-ray sources, has further increased the number of laboratories involved in x-ray imaging. The result is an ever increasing demand for x-ray optics with a very wide range of specifications, reflecting the particular type of x-ray imaging performed at different laboratories. We have been involved in all aspects of high resolution nanofabrication for a number of years, and we have explored many different methods of lithography, which, although unorthodox, open up possibilities, and increase our flexibility for the fabrication of different diffractive optical elements, as well as other types of nanostructures. The availability of brighter x-ray sources, means that the diffraction efficiency of the ZPs is becoming of secondary importance, a trend which will continue in the future. Resolution, however, is important and will always remain so. Resolution is directly related to the accuracy af pattern generation, as well as the ability to draw fine lines. This is the area towards which we have directed most of our efforts so far.

Oxygen ion-conducting dense ceramic

DOEpatents

Balachandran, Uthamalingam; Kleefisch, Mark S.; Kobylinski, Thaddeus P.; Morissette, Sherry L.; Pei, Shiyou

1998-01-01

Preparation, structure, and properties of mixed metal oxide compositions and their uses are described. Mixed metal oxide compositions of the invention have stratified crystalline structure identifiable by means of powder X-ray diffraction patterns. In the form of dense ceramic membranes, the present compositions demonstrate an ability to separate oxygen selectively from a gaseous mixture containing oxygen and one or more other volatile components by means of ionic conductivities.

Structure, optical and phonon properties of bulk and nanocrystalline Al2-xScx(WO4)3 solid solutions doped with Cr3+

NASA Astrophysics Data System (ADS)

Mączka, M.; Hermanowicz, K.; Pietraszko, A.; Yordanova, A.; Koseva, I.

2014-01-01

Pure and Cr3+ doped nanosized Al2-xScx(WO4)3 solid solutions were prepared by co-precipitation method as well as Al2-xScx(WO4)3 single crystals were grown by high-temperature flux method. The obtained samples were characterized by X-ray, Raman, IR, absorption and luminescence methods. Single crystal X-ray diffraction showed that AlSc(WO4)3 is orthorhombic at room temperature with space group Pnca and trivalent cations are statistically distributed. Raman and IR studies showed that Al2-xScx(WO4)3 solid solutions show "two mode" behavior. They also showed that vibrational properties of nanosized samples have been weakly modified in comparison with the bulk materials. The luminescence and absorption spectra revealed that chromium ions occupy two sites of weak and strong crystal field strength.

Investigating Li 2NiO 2–Li 2CuO 2 Solid Solutions as High-Capacity Cathode Materials for Li-Ion Batteries

DOE PAGES

Xu, Jing; Renfrew, Sara; Marcus, Matthew A.; ...

2017-05-11

Li 2Ni 1–xCu xO 2 solid solutions were prepared by a solid-state method to study the correlation between composition and electrochemical performance. Cu incorporation improved the phase purity of Li 2Ni 1–xCu xO 2 with orthorhombic Immm structure, resulting in enhanced capacity. However, the electrochemical profiles suggested Cu incorporation did not prevent irreversible phase transformation during the electrochemical process, instead, it likely influenced the phase transformation upon lithium removal. By combining ex situ X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and differential electrochemical mass spectrometry (DEMS) measurements, this study elucidates the relevant phase transformation (e.g., crystal structure, local environment, andmore » charge compensation) and participation of electrons from lattice oxygen during the first cycle in these complex oxides.« less

Observation of indium ion migration-induced resistive switching in Al/Mg{sub 0.5}Ca{sub 0.5}TiO{sub 3}/ITO

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

Lin, Zong-Han; Wang, Yeong-Her, E-mail: yhw@ee.ncku.edu.tw

2016-08-01

Understanding switching mechanisms is very important for resistive random access memory (RRAM) applications. This letter reports an investigation of Al/Mg{sub 0.5}Ca{sub 0.5}TiO{sub 3} (MCTO)/ITO RRAM, which exhibits bipolar resistive switching behavior. The filaments that connect Al electrodes with indium tin oxide electrodes across the MCTO layer at a low-resistance state are identified. The filaments composed of In{sub 2}O{sub 3} crystals are observed through energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, nanobeam diffraction, and comparisons of Joint Committee on Powder Diffraction Standards (JCPDS) cards. Finally, a switching mechanism resulting from an electrical field induced by In{sup 3+} ion migration is proposed.more » In{sup 3+} ion migration forms/ruptures the conductive filaments and sets/resets the RRAM device.« less

Ion beam analysis in cultural heritage studies: Milestones and perspectives

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

Dran, Jean-Claude; Calligaro, Thomas

2013-07-18

For three decades, ion beam analysis (IBA) in external mode was considered as the best choice for the characterisation of cultural heritage materials, as it combines excellent analytical performance and non-invasive character. However, in recent years, other analytical techniques arose as serious competitors, such as those based on synchrotron radiation (X-ray absorption, fluorescence or diffraction) or those using portable instruments (XRF, micro-Raman). It is shown that nevertheless IBA remains unmatched thanks to two unique features, namely the analysis of light elements and the high-resolution 3D chemical imaging.

Study on structural recovery of graphite irradiated with swift heavy ions at high temperature

NASA Astrophysics Data System (ADS)

Pellemoine, F.; Avilov, M.; Bender, M.; Ewing, R. C.; Fernandes, S.; Lang, M.; Li, W. X.; Mittig, W.; Schein, M.; Severin, D.; Tomut, M.; Trautmann, C.; Zhang, F. X.

2015-12-01

Thin graphite foils bombarded with an intense high-energy (8.6 MeV/u) gold beam reaching fluences up to 1 × 1015 ions/cm2 lead to swelling and electrical resistivity changes. As shown earlier, these effects are diminished with increasing irradiation temperature. The work reported here extends the investigation of beam induced changes of these samples by structural analysis using synchrotron X-ray diffraction and transmission electron microscope. A nearly complete recovery from swelling at irradiation temperatures above about 1500 °C is identified.

Synthesis of nanodimensional orthorhombic SnO2 thin films

NASA Astrophysics Data System (ADS)

Kondkar, V.; Rukade, D.; Kanjilal, D.; Bhattacharyya, V.

2018-04-01

Amorphous thin films of SnO2 are irradiated by swift heavy ions at two different fluences. Unirradiated as well as irradiated films are characterized by glancing angle X-ray diffraction (GAXRD), UV-Vis spectroscopy and atomic force microscopy (AFM). GAXRD study reveals formation of orthorhombic nanophases of SnO2. Nanophase formation is also confirmed by the quantum size effect manifested by blue shift in terms of increase in band gap energy. The size and shape of the irradiation induced surface structures depend on ion fluence.

Two-photon x-ray diffraction

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

Stohr, J.

The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a “source”, consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focused beyond the diffraction limit. Furthermore, the case of cloned photon pairs is compared to and distinguished from entangled photonmore » pairs or biphotons.« less

Two-photon x-ray diffraction

DOE PAGES

Stohr, J.

2017-01-11

The interference pattern of a circular photon source has long been used to define the optical diffraction limit. Here we show the breakdown of conventional x-ray diffraction theory for the fundamental case of a “source”, consisting of a back-illuminated thin film in a circular aperture. When the conventional spontaneous x-ray scattering by atoms in the film is replaced at high incident intensity by stimulated resonant scattering, the film becomes the source of cloned photon twins and the diffraction pattern becomes self-focused beyond the diffraction limit. Furthermore, the case of cloned photon pairs is compared to and distinguished from entangled photonmore » pairs or biphotons.« less

Characterization of X80 and X100 Microalloyed Pipeline Steel Using Quantitative X-ray Diffraction

NASA Astrophysics Data System (ADS)

Wiskel, J. B.; Li, X.; Ivey, D. G.; Henein, H.

2018-06-01

Quantitative X-ray diffraction characterization of four (4) X80 and three (3) X100 microalloyed steels was undertaken. The effect of through-thickness position, processing parameters, and composition on the measured crystallite size, microstrain, and J index (relative magnitude of crystallographic texture) was determined. Microstructure analysis using optical microscopy, scanning electron microscopy, transmission electron microscopy, and electron-backscattered diffraction was also undertaken. The measured value of microstrain increased with increasing alloy content and decreasing cooling interrupt temperature. Microstructural features corresponding to crystallite size in the X80 steels were both above and below the detection limit for quantitative X-ray diffraction. The X100 steels consistently exhibited microstructure features below the crystallite size detection limit. The yield stress of each steel increased with increasing microstrain. The increase in microstrain from X80 to X100 is also associated with a change in microstructure from predominantly polygonal ferrite to bainitic ferrite.

Ba0.06(Na,Bi)0.94Ti1-x(Ni1/3Nb2/3)xO3 ceramics: X-ray diffraction and infrared spectroscopy studies

NASA Astrophysics Data System (ADS)

Mishra, R. K.; Prasad, Ashutosh; Chandra, K. P.; Prasad, K.

2018-05-01

Non-lead ceramic samples of Ba0.06(Na0.5Bi0.5)0.94Ti1-x(Ni1/3Nb2/3)xO3; 0 ≤ x ≤ 1.0 were prepared by standard high temperature ceramic synthesis method. Rietveld refinements of X-ray diffraction data of these ceramics were carried out using FullProf software and determined their crystal symmetry, space group and unit cell dimensions. Rietveld refinement revealed that Ba0.06(Na0.5Bi0.5)0.94TiO3 has a monoclinic structure with space group P4/m while B0.06(Na0.5Bi0.5)0.94(Ni1/3Nb2/3)O3 has tetragonal (pseudo-cubic) structure with space group P4/mmm. Partial replacement of Ti4+ ion by pseudo-cation (Ni1/33 +Nb2/3 5 +) 4 + resulted in the change of unit cell structure from monoclinic to tetragonal. SEM studies were carried out in order to access the quality of the prepared ceramics which showed a change in grain sizes with the increase of (Ni1/33 +Nb2/3 5 +) 4 + content. FTIR spectra confirmed the formation of perovskite type solid solutions.

Transport of oxygen ions in Er doped La2Mo2O9 oxide ion conductors: Correlation with microscopic length scales

NASA Astrophysics Data System (ADS)

Paul, T.; Ghosh, A.

2018-01-01

We report oxygen ion transport in La2-xErxMo2O9 (0.05 ≤ x ≤ 0.25) oxide ion conductors. We have measured conductivity and dielectric spectra at different temperatures in a wide frequency range. The mean square displacement and spatial extent of non-random sub-diffusive regions are estimated from the conductivity spectra and dielectric spectra, respectively, using linear response theory. The composition dependence of the conductivity is observed to be similar to that of the spatial extent of non-random sub-diffusive regions. The behavior of the composition dependence of the mean square displacement of oxygen ions is opposite to that of the conductivity. The attempt frequency estimated from the analysis of the electric modulus agrees well with that obtained from the Raman spectra analysis. The full Rietveld refinement of X-ray diffraction data of the samples is performed to estimate the distance between different oxygen lattice sites. The results obtained from such analysis confirm the ion hopping within the spatial extent of non-random sub-diffusive regions.

The reduction mechanism of a natural chromite at 1416 °C

NASA Astrophysics Data System (ADS)

Soykan, O.; Eric, R. H.; King, R. P.

1991-02-01

The behavior of a natural chromite from the Bushveld Complex, Transvaal, South Africa, during reduction at 1416 °C by graphite was studied by means of thermogravimetric analysis, X-ray diffraction (XRD) analysis, energy-dispersive X-ray analysis (EDAX), and metallographic analysis. Experimental runs were allowed to proceed up to 120 minutes, resulting in 99 pct reduction. The specific objective of this study was to delineate the reduction mechanism of chromite by graphite. Zoning was observed in partially reduced chromites with degrees of reduction of up to about 70 pct. The inner cores were rich in iron, while the outer cores were depleted of iron. Energy-dispersive X-ray analysis revealed that Fe2+ and Cr3+ ions had diffused outward, whereas Cr2+, Al3+, and Mg2+ ions had diffused inward. The following mechanism of reduction, which is based on the assumption that the composition of the spinel phase remains stoichiometric with increasing degree of reduction, is proposed, (a) Initially, Fe3+ and Fe2+ ions at the surface of the chromite particle are reduced to the metallic state. This is followed immediately by the reduction of Cr3+ ions to the divalent state, (b) Cr2+ ions diffusing toward the center of the particle reduce the Fe3+ ions in the spinel under the surface of the particle to Fe2+ at the interface between the inner and outer cores. Fe2+ ions diffuse toward the surface, where they are reduced to metallic iron, (c) After the iron has been completely reduced, Cr3+ and any Cr2+ that is present are reduced to the metallic state, leaving an iron- and chromium-free spinel, MgAl2O4.

Diffractive-refractive optics: (+,-,-,+) X-ray crystal monochromator with harmonics separation.

PubMed

Hrdý, Jaromír; Mikulík, Petr; Oberta, Peter

2011-03-01

A new kind of two channel-cut crystals X-ray monochromator in dispersive (+,-,-,+) position which spatially separates harmonics is proposed. The diffracting surfaces are oriented so that the diffraction is inclined. Owing to refraction the diffracted beam is sagittally deviated. The deviation depends on wavelength and is much higher for the first harmonics than for higher harmonics. This leads to spatial harmonics separation. The idea is supported by ray-tracing simulation.

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

Jones, K.M.; Al-Jassim, M.M.; Williamson, D.L.

Over the last two decades extensive studies on the optical and electrical properties of hydrogenated amorphous Si (a-Si:H) have been reported. However, less attention was given to the structural characterization of this material partly due to the insensitivity to hydrogen of structural probes such as x-rays and electron diffraction. From a recent set of experiments, results on the solubility limit of hydrogen in a special type of a-Si:H and the characterization of hydrogen induced complexes or nanobubbles has been reported. In this study, we report TEM observations of the structural morphology of hydrogen related defects that support these recent measurementsmore » obtained by secondary ion mass spectrometry (SIMS) and small-angle x-ray scattering (SAXS).« less

Low temperature synthesis and characterization of carbonated hydroxyapatite nanocrystals

NASA Astrophysics Data System (ADS)

Anwar, Aneela; Asghar, Muhammad Nadeem; Kanwal, Qudsia; Kazmi, Mohsin; Sadiqa, Ayesha

2016-08-01

Carbonate substituted hydroxyapatite (CHA) nanorods were synthesized via coprecipitation method from aqueous solution of calcium nitrate tetrahydrate and diammonium hydrogen phosphate (with urea as carbonate ion source) in the presence of ammonium hydroxide solution at 70 °C at the conditions of pH 11. The obtained powders were physically characterized using transmission electron microscopy (TEM), X-ray powder diffraction analysis (XRD), and FTIR and Raman spectroscopy. The particle size was evaluated by Dynamic light scattering (DLS). The chemical structural analysis of as prepared sample was performed using X-ray photoelectron spectroscopy (XPS). After ageing for 12 h, and heat treatment at 1000 °C for 1 h, the product was obtained as highly crystalline nanorods of CHA.

Local structure analysis of diluted magnetic semiconductor Co and Al co-doped ZnO nanoparticles

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

Hyodo, K.; Morimoto, S.; Yamazaki, T.

2016-02-01

In this study, Co and Al ions co-doped ZnO nanoparticles (Zn(Al, Co)O NPs) were prepared by our original chemical preparation method. The obtained samples prepared by this method, were encapsulated in amorphous SiO{sub 2}. X-ray diffraction (XRD) results showed Zn(Al, Co)O NPs had a single-phase nature with hexagonal wurtzite structure. These particle sizes could be controlled to be approximately 30 nm. We investigate the effect that the increase in the carrier has on the magnetization by doping Al to Co-doped ZnO NPs. The local structures were qualitatively analyzed using X-ray absorption fine structure (XAFS) measurements.

Synthesis and Characterization of YVO4-Based Phosphor Doped with Eu3+ Ions for Display Devices

NASA Astrophysics Data System (ADS)

Thakur, Shashi; Gathania, Arvind K.

2015-10-01

YVO4:Eu nanophosphor has been synthesized by the sol-gel method. Samples were characterized by x-ray diffraction (XRD), energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, photoluminescence, and Raman spectroscopy. The XRD profile confirms the tetragonal phase of the Eu3+-doped YVO4 nanophosphor. The efficiency of the prepared phosphor was analyzed by means of its emission spectral profile. We also observed rich red emission from the prepared phosphor on excitation by an ultraviolet source. The calculated Commission International de l'Éclairage coordinates reveal excellent color purity efficiency. Such luminescent powder is useful as red phosphor in display device applications.

Room Temperature Elastic Moduli and Vickers Hardness of Hot-Pressed LLZO Cubic Garnet

DTIC Science & Technology

2012-01-01

polishing compounds, Leco, St. Joseph, MI). X - ray diffraction and scanning electron microscopy (SEM) The microstructure of the hot-pressed specimens...was examined on uncoated fracture surfaces by SEM with an accelerating voltage of 1 and 3 kV. Phase purity was evaluated from X - ray diffraction data...the micro- structure appeared to be homogenous for the two hot- pressed LLZO specimens included in this study (Fig. 1). X - ray diffraction confirmed that

Method for improve x-ray diffraction determinations of residual stress in nickel-base alloys

DOEpatents

Berman, Robert M.; Cohen, Isadore

1990-01-01

A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys which comprises covering part of a predetermined area of the surface of a nickel-base alloy with a dispersion, exposing the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample.

Crystal structure and density of helium to 232 kbar

NASA Technical Reports Server (NTRS)

Mao, H. K.; Wu, Y.; Jephcoat, A. P.; Hemley, R. J.; Bell, P. M.; Bassett, W. A.

1988-01-01

The properties of helium and hydrogen at high pressure are topics of great interest to the understanding of planetary interiors. These materials constitute 95 percent of the entire solar system. A technique was presented for the measurement of X-ray diffraction from single-crystals of low-Z condenses gases in a diamond-anvil cell at high pressure. The first such single-crystal X-ray diffraction measurements on solid hydrogen to 26.5 GPa were presented. The application of this technique to the problem of the crystal structure, equation of state, and phase diagram of solid helium is reported. Crucial for X-ray diffraction studies of these materials is the use of a synchrotron radiation source which provides high brillance, narrow collimation of the incident and diffracted X-ray beams to reduce the background noise, and energy-dispersive diffraction techniques with polychromatic (white) radiation, which provides high detection efficiency.

Structural investigation of porcine stomach mucin by X-ray fiber diffraction and homology modeling

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

Veluraja, K., E-mail: veluraja@msuniv.ac.in; Vennila, K.N.; Umamakeshvari, K.

Research highlights: {yields} Techniques to get oriented mucin fibre. {yields} X-ray fibre diffraction pattern for mucin. {yields} Molecular modeling of mucin based on X-ray fibre diffraction pattern. -- Abstract: The basic understanding of the three dimensional structure of mucin is essential to understand its physiological function. Technology has been developed to achieve orientated porcine stomach mucin molecules. X-ray fiber diffraction of partially orientated porcine stomach mucin molecules show d-spacing signals at 2.99, 4.06, 4.22, 4.7, 5.37 and 6.5 A. The high intense d-spacing signal at 4.22 A is attributed to the antiparallel {beta}-sheet structure identified in the fraction of themore » homology modeled mucin molecule (amino acid residues 800-980) using Nidogen-Laminin complex structure as a template. The X-ray fiber diffraction signal at 6.5 A reveals partial organization of oligosaccharides in porcine stomach mucin. This partial structure of mucin will be helpful in establishing a three dimensional structure for the whole mucin molecule.« less

Formation of Semimetallic Cobalt Telluride Nanotube Film via Anion Exchange Tellurization Strategy in Aqueous Solution for Electrocatalytic Applications.

PubMed

Patil, Supriya A; Kim, Eun-Kyung; Shrestha, Nabeen K; Chang, Jinho; Lee, Joong Kee; Han, Sung-Hwan

2015-11-25

Metal telluride nanostructures have demonstrated several potential applications particularly in harvesting and storing green energy. Metal tellurides are synthesized by tellurization process performed basically at high temperature in reducing gas atmosphere, which makes the process expensive and complicated. The development of a facile and economical process for desirable metal telluride nanostructures without complicated manipulation is still a challenge. In an effort to develop an alternative strategy of tellurization, herein we report a thin film formation of self-standing cobalt telluride nanotubes on various conducting and nonconducting substrates using a simple binder-free synthetic strategy based on anion exchange transformation from a thin film of cobalt hydroxycarbonate nanostructures in aqueous solution at room temperature. The nanostructured films before and after ion exchange transformation reaction are characterized using field emission scanning electron microscope, energy dispersive X-ray analyzer, X-ray photoelectron spectroscopy, thin film X-ray diffraction technique, high resolution transmission electron microscope, and selected area electron diffraction analysis technique. After the ion exchange transformation of nanostructures, the film shows conversion from insulator to highly electrical conductive semimetallic characteristic. When used as a counter electrode in I3(-)/I(-) redox electrolyte based dye-sensitized solar cells, the telluride film exhibits an electrocatalytic reduction activity for I3(-) with a demonstration of solar-light to electrical power conversion efficiency of 8.10%, which is highly competitive to the efficiency of 8.20% exhibited by a benchmarked Pt-film counter electrode. On the other hand, the telluride film electrode also demonstrates electrocatalytic activity for oxygen evolution reaction from oxidation of water.

A nearly on-axis spectroscopic system for simultaneously measuring UV-visible absorption and X-ray diffraction in the SPring-8 structural genomics beamline.

PubMed

Sakaguchi, Miyuki; Kimura, Tetsunari; Nishida, Takuma; Tosha, Takehiko; Sugimoto, Hiroshi; Yamaguchi, Yoshihiro; Yanagisawa, Sachiko; Ueno, Go; Murakami, Hironori; Ago, Hideo; Yamamoto, Masaki; Ogura, Takashi; Shiro, Yoshitsugu; Kubo, Minoru

2016-01-01

UV-visible absorption spectroscopy is useful for probing the electronic and structural changes of protein active sites, and thus the on-line combination of X-ray diffraction and spectroscopic analysis is increasingly being applied. Herein, a novel absorption spectrometer was developed at SPring-8 BL26B2 with a nearly on-axis geometry between the X-ray and optical axes. A small prism mirror was placed near the X-ray beamstop to pass the light only 2° off the X-ray beam, enabling spectroscopic analysis of the X-ray-exposed volume of a crystal during X-ray diffraction data collection. The spectrometer was applied to NO reductase, a heme enzyme that catalyzes NO reduction to N2O. Radiation damage to the heme was monitored in real time during X-ray irradiation by evaluating the absorption spectral changes. Moreover, NO binding to the heme was probed via caged NO photolysis with UV light, demonstrating the extended capability of the spectrometer for intermediate analysis.

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

Insights into the Effects of Zinc Doping on Structural Phase Transition of P2-Type Sodium Nickel Manganese Oxide Cathodes for High-Energy Sodium Ion Batteries.

PubMed

Wu, Xuehang; Xu, Gui-Liang; Zhong, Guiming; Gong, Zhengliang; McDonald, Matthew J; Zheng, Shiyao; Fu, Riqiang; Chen, Zonghai; Amine, Khalil; Yang, Yong

2016-08-31

P2-type sodium nickel manganese oxide-based cathode materials with higher energy densities are prime candidates for applications in rechargeable sodium ion batteries. A systematic study combining in situ high energy X-ray diffraction (HEXRD), ex situ X-ray absorption fine spectroscopy (XAFS), transmission electron microscopy (TEM), and solid-state nuclear magnetic resonance (SS-NMR) techniques was carried out to gain a deep insight into the structural evolution of P2-Na0.66Ni0.33-xZnxMn0.67O2 (x = 0, 0.07) during cycling. In situ HEXRD and ex situ TEM measurements indicate that an irreversible phase transition occurs upon sodium insertion-extraction of Na0.66Ni0.33Mn0.67O2. Zinc doping of this system results in a high structural reversibility. XAFS measurements indicate that both materials are almost completely dependent on the Ni(4+)/Ni(3+)/Ni(2+) redox couple to provide charge/discharge capacity. SS-NMR measurements indicate that both reversible and irreversible migration of transition metal ions into the sodium layer occurs in the material at the fully charged state. The irreversible migration of transition metal ions triggers a structural distortion, leading to the observed capacity and voltage fading. Our results allow a new understanding of the importance of improving the stability of transition metal layers.

Evidence from x-ray and neutron powder diffraction patterns that the so-called icosahedral and decagonal quasicrystals of MnAl(6) and other alloys are twinned cubic crystals.

PubMed

Pauling, L

1987-06-01

It is shown that the x-ray powder diffraction patterns of rapidly quenched MnAl(6) and Mg(32)(Al,Zn)(49) and the neutron powder diffraction pattern of MnAl(6) are compatible with the proposed 820-atom primitive cubic structure [Pauling, L. (1987) Phys. Rev. Lett. 58, 365-368]. The values found for the edge of the unit cube are 23.365 A (x-ray) and 23.416 A (neutron) for MnAl(6) and 24.313 A (x-ray) for Mg(32)(Al,Zn)(49).

Evidence from x-ray and neutron powder diffraction patterns that the so-called icosahedral and decagonal quasicrystals of MnAl6 and other alloys are twinned cubic crystals

PubMed Central

Pauling, Linus

1987-01-01

It is shown that the x-ray powder diffraction patterns of rapidly quenched MnAl6 and Mg32(Al,Zn)49 and the neutron powder diffraction pattern of MnAl6 are compatible with the proposed 820-atom primitive cubic structure [Pauling, L. (1987) Phys. Rev. Lett. 58, 365-368]. The values found for the edge of the unit cube are 23.365 Å (x-ray) and 23.416 Å (neutron) for MnAl6 and 24.313 Å (x-ray) for Mg32(Al,Zn)49. PMID:16593841

Vapor phase diamond growth technology

NASA Technical Reports Server (NTRS)

Angus, J. C.

1981-01-01

Ion beam deposition chambers used for carbon film generation were designed and constructed. Features of the developed equipment include: (1) carbon ion energies down to approx. 50 eV; (2) in suit surface monitoring with HEED; (3) provision for flooding the surface with ultraviolet radiation; (4) infrared laser heating of substrate; (5) residual gas monitoring; (6) provision for several source gases, including diborane for doping studies; and (7) growth from either hydrocarbon source gases or from carbon/argon arc sources. Various analytical techniques for characterization of from carbon/argon arc sources. Various analytical techniques for characterization of the ion deposited carbon films used to establish the nature of the chemical bonding and crystallographic structure of the films are discussed. These include: H2204/HN03 etch; resistance measurements; hardness tests; Fourier transform infrared spectroscopy; scanning auger microscopy; electron spectroscopy for chemical analysis; electron diffraction and energy dispersive X-ray analysis; electron energy loss spectroscopy; density measurements; secondary ion mass spectroscopy; high energy electron diffraction; and electron spin resonance. Results of the tests are summarized.

High-energy X-ray diffraction using the Pixium 4700 flat-panel detector.

PubMed

Daniels, J E; Drakopoulos, M

2009-07-01

The Pixium 4700 detector represents a significant step forward in detector technology for high-energy X-ray diffraction. The detector design is based on digital flat-panel technology, combining an amorphous Si panel with a CsI scintillator. The detector has a useful pixel array of 1910 x 2480 pixels with a pixel size of 154 microm x 154 microm, and thus it covers an effective area of 294 mm x 379 mm. Designed for medical imaging, the detector has good efficiency at high X-ray energies. Furthermore, it is capable of acquiring sequences of images at 7.5 frames per second in full image mode, and up to 60 frames per second in binned region of interest modes. Here, the basic properties of this detector applied to high-energy X-ray diffraction are presented. Quantitative comparisons with a widespread high-energy detector, the MAR345 image plate scanner, are shown. Other properties of the Pixium 4700 detector, including a narrow point-spread function and distortion-free image, allows for the acquisition of high-quality diffraction data at high X-ray energies. In addition, high frame rates and shutterless operation open new experimental possibilities. Also provided are the necessary data for the correction of images collected using the Pixium 4700 for diffraction purposes.

Characterization of TiN/B-C-N multilayers by transmission electron microscopy, ion beam backscattering, and low angle x-ray diffraction

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

Kung, H.; Fayeulle, S.; Nastasi, M.

1997-10-01

The effects of Ar ion irradiation on the structure and stability of multilayered DC sputtered thin films of TiN/B-C-N have been studied. An increase of the bilayer repeat length to a maximum of 12.8% and departure of nitrogen from the film was observed indicating the interdiffusion between TiN and B-C-N layers. For the highest dose (5 {times} 10{sup 16} ions/cm{sup 2}) the multilayered structure partly disappears. The various mechanisms are discussed in terms of stress-driven diffusion and viscous flow of atoms.

Enhancement of Curie temperature of barium hexaferrite by dense electronic excitations

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

Sharma, Manju; Kashyap, Subhash C.; Gupta, Hem C.

2014-07-15

Curie temperature of polycrystalline barium hexaferrite (BaFe{sub 12}O{sub 19}), prepared by conventional solid state technique, is anomalously and significantly enhanced (by nearly 15%) by energetic heavy ion irradiation (150 MeV, Ag{sup 12+}) at ambient temperature due to dense electronic excitations Moderate fluence (1 × 10{sup 12} ions/cm{sup 2}) induces structural defects giving rise to above enhancement. As established by X-ray diffraction, scanning electron microscopy and Raman studies, higher fluence (1 × 10{sup 13} ions/cm{sup 2}) has structurally transformed the sample to amorphous phase with marginal change in magnetization and Curie temperature.

Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

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

Ozcan, Ahmet S., E-mail: asozcan@us.ibm.com; Lavoie, Christian; Jordan-Sweet, Jean

We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

Structural, magnetic and electronic structure properties of Co doped ZnO nanoparticles

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

Kumar, Shalendra, E-mail: shailuphy@gmail.com; School of Materials Science and Engineering, Changwon National University, Changwon, Gyeongnam 641-773; Song, T.K., E-mail: tksong@changwon.ac.kr

Highlights: • XRD and HR-TEM results show the single phase nature of Co doped ZnO nanoparticles. • XMCD and dc magnetization results indicate the RT-FM in Co doped ZnO nanoparticles. • Co L{sub 3,2} NEXAFS spectra infer that Co ions are in 2+ valence state. • O K edge NEXAFS spectra show that O vacancy increases with Co doping in ZnO. - Abstract: We reported structural, magnetic and electronic structure studies of Co doped ZnO nanoparticles. Doping of Co ions in ZnO host matrix has been studied and confirmed using various methods; such as X-ray diffraction (XRD), field emission scanningmore » electron microscopy (FE-SEM), energy dispersed X-ray (EDX), high resolution transmission electron microscopy (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), near edge X-ray absorption fine structure (NEXAFS) spectroscopy, magnetic hysteresis loop measurements and X-ray magnetic circular dichroism (XMCD). From the XRD and HR-TEM results, it is observed that Co doped ZnO nanoparticles have single phase nature with wurtzite structure and exclude the possibility of secondary phase formation. FE-SEM and TEM micrographs show that pure and Co doped nanoparticles are nearly spherical in shape. O K edge NEXAFS spectra indicate that O vacancies increase with Co doping. The Co L{sub 3,2} edge NEXAFS spectra revealed that Co ions are in 2+ valence state. DC magnetization hysteresis loops and XMCD results clearly showed the intrinsic origin of temperature ferromagnetism in Co doped ZnO nanoparticles.« less

Crystallization and preliminary X-ray diffraction analysis of a chitin-binding domain of hyperthermophilic chitinase from Pyrococcus furiosus

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

Nakamura, Tsutomu; Ishikawa, Kazuhiko; Hagihara, Yoshihisa

The expression, purification and preliminary X-ray diffraction studies of a chitin-binding domain of the chitinase from P. furiosus are reported. The crystallization and preliminary X-ray diffraction analysis of the chitin-binding domain of chitinase from a hyperthermophilic archaeon, Pyrococcus furiosus, are reported. The recombinant protein was prepared using an Escherichia coli overexpression system and was crystallized by the hanging-drop vapour-diffusion method. An X-ray diffraction data set was collected to 1.70 Å resolution. The crystal belonged to space group P4{sub 3}2{sub 1}2 or P4{sub 1}2{sub 1}2. The unit-cell parameters were determined to be a = b = 48.8, c = 85.0 Å.

Long-Wavelength X-Ray Diffraction and Its Applications in Macromolecular Crystallography.

PubMed

Weiss, Manfred S

2017-01-01

For many years, diffraction experiments in macromolecular crystallography at X-ray wavelengths longer than that of Cu-K α (1.54 Å) have been largely underappreciated. Effects caused by increased X-ray absorption result in the fact that these experiments are more difficult than the standard diffraction experiments at short wavelengths. However, due to the also increased anomalous scattering of many biologically relevant atoms, important additional structural information can be obtained. This information, in turn, can be used for phase determination, for substructure identification, in molecular replacement approaches, as well as in structure refinement. This chapter reviews the possibilities and the difficulties associated with such experiments, and it provides a short description of two macromolecular crystallography synchrotron beam lines dedicated to long-wavelength X-ray diffraction experiments.

Structural study of Ti-doped CoFe{sub 2}O{sub 4} mixed spinel ferrite

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

Choudhary, P., E-mail: pankaj.7007@rediffmail.com; Sharma, P.; Dar, M. A.

2016-05-06

We present the results on atomic and lattice structure of the polycrystalline spinel ferrites system Co{sub 1-x} Ti{sub x}Fe{sub 2}O{sub 4} (x = 0.0, 0.25, 0.50) synthesized by following the conventional solid-state reaction route. The observed X-ray diffraction (XRD) data confirms that all the prepared samples are indexed in cubic crystal structure (space group Fd3m). Diffraction pattern showed TiO{sub 2} phase due to presence of Ti{sup +4} ions. Four Raman active phonon modes are observed for CoFe{sub 2}O{sub 4} sample existing around 295, 462, 585, 689, cm{sup −1} as Eg, T{sub 2g}(2), T{sub 2g}(3), and A{sub 1g}, respectively. With 25more » % Ti ion doping, the peak T{sub 2g}(3) disappears, while to that T{sub 2g}(1) emerges. This is an indication of presence of TiO{sub 2} phase in Co{sub 0.75}Ti{sub 0.25}Fe{sub 2}O{sub 4} and Co{sub 0.5}Ti{sub 0.5}Fe{sub 2}O{sub 4} ceramics.« less

Electrical enhancement of direct methanol fuel cells by metal-plasma ion implantation Pt-Ru/C multilayer catalysts.

PubMed

Weng, Ko-Wei; Chen, Yung-Lin; Chen, Ya-Chi; Lin, Tai-Nan

2009-02-01

Direct methanol fuel cells (DMFC) have been widely studied owing to their simple cell configuration, high volume energy density, short start-up time, high operational reliability and other favorable characteristics. However, major limitations include high production cost, poisoning of the catalyst and methanol crossover. This study adopts a simple technique for preparing Pt-Ru/C multilayer catalysts, including magnetron sputtering (MS) and metal-plasma ion implantation (MPII). The Pt catalysts were sputtered onto the gas diffusion layer (GDL), followed by the implantation of Ru catalysts using MPII (at an accelerating voltage of 20 kV and an implantation dose of 1 x 10(16) ions/cm2). Pt-Ru is repeatedly processed to prepare Pt-Ru/C multilayer catalysts. The catalyst film structure and microstructure were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electronic microscopy (SEM), respectively. The cell performance was tested using a potential stat/galvano-stat. The results reveal that the membrane electrode assembly (MEA) of four multilayer structures enhances the cell performance of DMFC. The measured power density is 2.2 mW/cm2 at a methanol concentration of 2 M, with an OCV of 0.493 V.

Data processing software suite SITENNO for coherent X-ray diffraction imaging using the X-ray free-electron laser SACLA.

PubMed

Sekiguchi, Yuki; Oroguchi, Tomotaka; Takayama, Yuki; Nakasako, Masayoshi

2014-05-01

Coherent X-ray diffraction imaging is a promising technique for visualizing the structures of non-crystalline particles with dimensions of micrometers to sub-micrometers. Recently, X-ray free-electron laser sources have enabled efficient experiments in the `diffraction before destruction' scheme. Diffraction experiments have been conducted at SPring-8 Angstrom Compact free-electron LAser (SACLA) using the custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors. In the experiments, ten thousands of single-shot diffraction patterns can be collected within several hours. Then, diffraction patterns with significant levels of intensity suitable for structural analysis must be found, direct-beam positions in diffraction patterns determined, diffraction patterns from the two CCD detectors merged, and phase-retrieval calculations for structural analyses performed. A software suite named SITENNO has been developed to semi-automatically apply the four-step processing to a huge number of diffraction data. Here, details of the algorithm used in the suite are described and the performance for approximately 9000 diffraction patterns collected from cuboid-shaped copper oxide particles reported. Using the SITENNO suite, it is possible to conduct experiments with data processing immediately after the data collection, and to characterize the size distribution and internal structures of the non-crystalline particles.

Data processing software suite SITENNO for coherent X-ray diffraction imaging using the X-ray free-electron laser SACLA

PubMed Central

Sekiguchi, Yuki; Oroguchi, Tomotaka; Takayama, Yuki; Nakasako, Masayoshi

2014-01-01

Coherent X-ray diffraction imaging is a promising technique for visualizing the structures of non-crystalline particles with dimensions of micrometers to sub-micrometers. Recently, X-ray free-electron laser sources have enabled efficient experiments in the ‘diffraction before destruction’ scheme. Diffraction experiments have been conducted at SPring-8 Angstrom Compact free-electron LAser (SACLA) using the custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors. In the experiments, ten thousands of single-shot diffraction patterns can be collected within several hours. Then, diffraction patterns with significant levels of intensity suitable for structural analysis must be found, direct-beam positions in diffraction patterns determined, diffraction patterns from the two CCD detectors merged, and phase-retrieval calculations for structural analyses performed. A software suite named SITENNO has been developed to semi-automatically apply the four-step processing to a huge number of diffraction data. Here, details of the algorithm used in the suite are described and the performance for approximately 9000 diffraction patterns collected from cuboid-shaped copper oxide particles reported. Using the SITENNO suite, it is possible to conduct experiments with data processing immediately after the data collection, and to characterize the size distribution and internal structures of the non-crystalline particles. PMID:24763651

X-Ray diffraction and mu-Raman investigation of the monoclinic-orthorhombic phase transition in Th(1-x)U(x)(C(2)O(4))(2).2H(2)O solid solutions.

PubMed

Clavier, Nicolas; Hingant, Nina; Rivenet, Murielle; Obbade, Saïd; Dacheux, Nicolas; Barré, Nicole; Abraham, Francis

2010-02-15

A complete Th(1-x)U(x)(C(2)O(4))(2).2H(2)O solid solution was prepared by mild hydrothermal synthesis from a mixture of hydrochloric solutions containing cations and oxalic acid. The crystal structure has been solved from twinned single crystals for x = 0, 0.5, and 1 with monoclinic symmetry, space group C2/c, leading to unit cell parameters of a approximately 10.5 A, b approximately 8.5 A, and c approximately 9.6 A. The crystal structure consists of a two-dimensional arrangement of actinide centers connected through bis-bidentate oxalate ions forming squares. The actinide metal is coordinated by eight oxygen atoms from four oxalate entities and two water oxygen atoms forming a bicapped square antiprism. The connection between the layers is assumed by hydrogen bonds between the water molecules and the oxygen of oxalate of an adjacent layer. Under these conditions, the unit cell contains two independent oxalate ions. From high-temperature mu-Raman and X-ray diffraction studies, the compounds were found to undergo a transition to an orthorhombic form (space group Ccca). The major differences in the structural arrangement concern the symmetry of uranium, which decreases from C2 to D2, leading to a unique oxalate group. Consequently, the nu(s)(C-O) double band observed in the Raman spectra recorded at room temperature turned into a singlet. This transformation was then used to make the phase transition temperature more precise as a function of the uranium content of the sample.

Nanostructured zirconium phosphate as ion exchanger: Synthesis, size dependent property and analytical application in radiochemical separation.

PubMed

Chakraborty, Rajesh; Bhattacharaya, Koustava; Chattopadhyay, Pabitra

2014-02-01

Nanostructured zirconium phosphates (ZPs) of different sizes were synthesized using Tritron X-100 (polyethylene glycol-p-isooctylphenyl ether) surfactant. The materials were characterized by FTIR and powdered X-ray diffraction (XRD). The structural and morphological details of the material were established by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The SEM study was followed by energy dispersive spectroscopic analysis (EDS) for elemental analysis of the sample. The particle sizes were determined by dynamic light scattering (DLS) method. Ion exchange capacity of these nanomaterials towards different metal ions was measured and size-dependent ion exchange property of the materials was investigated thoroughly. The nanomaterial of the smallest size (ca. 21.04nm) was employed to separate carrier-free (137m)Ba from (137)Cs in column chromatographic technique using 1.0M HNO3 as eluting agent at pH=5. © 2013 Elsevier Ltd. All rights reserved.

Spectroscopic imaging, diffraction, and holography with x-ray photoemission

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

Not Available

1992-02-01

X-ray probes are capable of determining the spatial structure of an atom in a specific chemical state, over length scales from about a micron all the way down to atomic resolution. Examples of these probes include photoemission microscopy, energy-dependent photoemission diffraction, photoelectron holography, and X-ray absorption microspectroscopy. Although the method of image formation, chemical-state sensitivity, and length scales can be very different, these X-ray techniques share a common goal of combining a capability for structure determination with chemical-state specificity. This workshop will address recent advances in holographic, diffraction, and direct imaging techniques using X-ray photoemission on both theoretical and experimentalmore » fronts. A particular emphasis will be on novel structure determinations with atomic resolution using photoelectrons.« less

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides.

PubMed

Ju, Guangxu; Highland, Matthew J; Yanguas-Gil, Angel; Thompson, Carol; Eastman, Jeffrey A; Zhou, Hua; Brennan, Sean M; Stephenson, G Brian; Fuoss, Paul H

2017-03-01

We describe an instrument that exploits the ongoing revolution in synchrotron sources, optics, and detectors to enable in situ studies of metal-organic vapor phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray methods. The system includes high-resolution positioning of the sample and detector including full rotations, an x-ray transparent chamber wall for incident and diffracted beam access over a wide angular range, and minimal thermal sample motion, giving the sub-micron positional stability and reproducibility needed for coherent x-ray studies. The instrument enables surface x-ray photon correlation spectroscopy, microbeam diffraction, and coherent diffraction imaging of atomic-scale surface and film structure and dynamics during growth, to provide fundamental understanding of MOVPE processes.

An instrument for in situ coherent x-ray studies of metal-organic vapor phase epitaxy of III-nitrides

NASA Astrophysics Data System (ADS)

Ju, Guangxu; Highland, Matthew J.; Yanguas-Gil, Angel; Thompson, Carol; Eastman, Jeffrey A.; Zhou, Hua; Brennan, Sean M.; Stephenson, G. Brian; Fuoss, Paul H.

2017-03-01

We describe an instrument that exploits the ongoing revolution in synchrotron sources, optics, and detectors to enable in situ studies of metal-organic vapor phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray methods. The system includes high-resolution positioning of the sample and detector including full rotations, an x-ray transparent chamber wall for incident and diffracted beam access over a wide angular range, and minimal thermal sample motion, giving the sub-micron positional stability and reproducibility needed for coherent x-ray studies. The instrument enables surface x-ray photon correlation spectroscopy, microbeam diffraction, and coherent diffraction imaging of atomic-scale surface and film structure and dynamics during growth, to provide fundamental understanding of MOVPE processes.

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers

NASA Astrophysics Data System (ADS)

Parrot, I. M.; Urban, V.; Gardner, K. H.; Forsyth, V. T.

2005-08-01

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar® or Twaron®.

Conceptual Design for Time-Resolved X-ray Diffraction in a Single Laser-Driven Compression Experiment

NASA Astrophysics Data System (ADS)

Benedetti, Laura Robin; Eggert, J. H.; Kilkenny, J. D.; Bradley, D. K.; Bell, P. M.; Palmer, N. E.; Rygg, J. R.; Boehly, T. R.; Collins, G. W.; Sorce, C.

2017-06-01

Since X-ray diffraction is the most definitive method for identifying crystalline phases of a material, it is an important technique for probing high-energy-density materials during laser-driven compression experiments. We are developing a design for collecting several x-ray diffraction datasets during a single laser-driven experiment, with a goal of achieving temporal resolution better than 1ns. The design combines x-ray streak cameras, for a continuous temporal record of diffraction, with fast x-ray imagers, to collect several diffraction patterns with sufficient solid angle range and resolution to identify crystalline texture. Preliminary experiments will be conducted at the Omega laser and then implemented at the National Ignition Facility. We will describe the status of the conceptual design, highlighting tradeoffs in the design process. We will also discuss the technical issues that must be addressed in order to develop a successful experimental platform. These include: Facility-specific geometric constraints such as unconverted laser light and target alignment; EMP issues when electronic diagnostics are close to the target; X-ray source requirements; and detector capabilities. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344, LLNL-ABS-725146.

A pseudo-tetragonal tungsten bronze superstructure: a combined solution of the crystal structure of K6.4(Nb,Ta)(36.3)O94 with advanced transmission electron microscopy and neutron diffraction.

PubMed

Paria Sena, Robert; Babaryk, Artem A; Khainakov, Sergiy; Garcia-Granda, Santiago; Slobodyanik, Nikolay S; Van Tendeloo, Gustaaf; Abakumov, Artem M; Hadermann, Joke

2016-01-21

The crystal structure of the K6.4Nb28.2Ta8.1O94 pseudo-tetragonal tungsten bronze-type oxide was determined using a combination of X-ray powder diffraction, neutron diffraction and transmission electron microscopy techniques, including electron diffraction, high angle annular dark field scanning transmission electron microscopy (HAADF-STEM), annular bright field STEM (ABF-STEM) and energy-dispersive X-ray compositional mapping (STEM-EDX). The compound crystallizes in the space group Pbam with unit cell parameters a = 37.468(9) Å, b = 12.493(3) Å, c = 3.95333(15) Å. The structure consists of corner sharing (Nb,Ta)O6 octahedra forming trigonal, tetragonal and pentagonal tunnels. All tetragonal tunnels are occupied by K(+) ions, while 1/3 of the pentagonal tunnels are preferentially occupied by Nb(5+)/Ta(5+) and 2/3 are occupied by K(+) in a regular pattern. A fractional substitution of K(+) in the pentagonal tunnels by Nb(5+)/Ta(5+) is suggested by the analysis of the HAADF-STEM images. In contrast to similar structures, such as K2Nb8O21, also parts of the trigonal tunnels are fractionally occupied by K(+) cations.

Locating active-site hydrogen atoms in d-xylose isomerase: Time-of-flight neutron diffraction

PubMed Central

Katz, Amy K.; Li, Xinmin; Carrell, H. L.; Hanson, B. Leif; Langan, Paul; Coates, Leighton; Schoenborn, Benno P.; Glusker, Jenny P.; Bunick, Gerard J.

2006-01-01

Time-of-flight neutron diffraction has been used to locate hydrogen atoms that define the ionization states of amino acids in crystals of d-xylose isomerase. This enzyme, from Streptomyces rubiginosus, is one of the largest enzymes studied to date at high resolution (1.8 Å) by this method. We have determined the position and orientation of a metal ion-bound water molecule that is located in the active site of the enzyme; this water has been thought to be involved in the isomerization step in which d-xylose is converted to d-xylulose or d-glucose to d-fructose. It is shown to be water (rather than a hydroxyl group) under the conditions of measurement (pH 8.0). Our analyses also reveal that one lysine probably has an −NH2-terminal group (rather than NH3+). The ionization state of each histidine residue also was determined. High-resolution x-ray studies (at 0.94 Å) indicate disorder in some side chains when a truncated substrate is bound and suggest how some side chains might move during catalysis. This combination of time-of-flight neutron diffraction and x-ray diffraction can contribute greatly to the elucidation of enzyme mechanisms. PMID:16707576

Low temperature nucleation of Griffiths Phase in Co doped LaMnO3 nanostructures

NASA Astrophysics Data System (ADS)

Adeela, N.; Khan, U.; Naz, S.; Iqbal, M.; Irfan, M.; Cheng, Y.

2017-11-01

We have reported magnetic properties of La1-xCoxMnO3 nanostructures synthesized by hydrothermal route. The crystal structure has been characterized by X-ray diffraction (XRD) technique, which shows rhombohedral perovskite structure at room temperature. Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) have been used to analyse morphology and chemical composition of prepared nanoparticles. Magnetic hysteresis loops of all the samples exhibit ferromagnetic behaviour at 10 K. Inverse susceptibility graphs as a function of temperature represent deviation from Curie Weiss law. The indication for short range ferromagnetic clusters well above Curie temperature is observed due to the Griffiths Phase (GP). It is proposed that the presence of GP arises from induced size effects of La and Co ions.

Photoassisted reduction of metal ions and organic dye by titanium dioxide nanoparticles in aqueous solution under anoxic conditions.

PubMed

Doong, Ruey-An; Hsieh, Tien-Chin; Huang, Chin-Pao

2010-07-15

The photoassisted reduction of metal ions and organic dye by metal-deposited Degussa P25 TiO(2) nanoparticles was investigated. Copper and silver ions were selected as the target metal ions to modify the surface properties of TiO(2) and to enhance the photocatalytic activity of TiO(2) towards methylene blue (MB) degradation. X-ray powder diffraction (XRPD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) were used to characterize the crystallinity, chemical species and morphology of metal-deposited TiO(2), respectively. Results showed that the particle size of metal-deposited TiO(2) was larger than that of Degussa P25 TiO(2). Based on XRPD patterns and XPS spectra, it was observed that the addition of formate promoted the photoreduction of metal ion by lowering its oxidation number, and subsequently enhancing the photodegradation efficiency and rate of MB. The pseudo-first-order rate constant (k(obs)) for MB photodegradation by Degussa P25 TiO(2) was 3.94 x 10(-2) min(-1) and increased by 1.4-1.7 times in k(obs) with metal-deposited TiO(2) for MB photodegradation compared to simple Degussa P25 TiO(2). The increase in mass loading of metal ions significantly enhanced the photodegradation efficiency of MB; the k(obs) for MB degradation increased from 3.94 x 10(-2) min(-1) in the absence of metal ion to 4.64-7.28 x 10(-2) min(-1) for Ag/TiO(2) and to 5.14-7.61 x 10(-2) min(-1) for Cu/TiO(2). In addition, the electrons generated from TiO(2) can effectively reduce metal ions and MB simultaneously under anoxic conditions. However, metal ions and organic dye would compete for electrons from the illuminated TiO(2). Copyright 2010 Elsevier B.V. All rights reserved.

Synthesis of non-toxic As and Cr nanoparticles through redox activity of highly flexible layered coordination polymer of Ni(II).

PubMed

Agarwal, Rashmi A

2018-03-09

A simple method for the sequestration of As(III) and Cr(VI) from water has been demonstrated by utilizing a highly flexible porous coordination polymer (PCP) of Ni(II) in its as synthesized form or without solvent removal. This PCP reduces the high toxicity of As(III) and Cr(VI) ions into non-toxic As(0) and Cr/Cr 2 O 3 /CrO 2 (zero, tri and tetravalent) nanoparticles (NPs) within its pores, and this is characterized by powder x-ray diffraction, x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. The high functionality of this polymer is due to the presence of monodentate carboxylate groups of a benzenetricarboxylate linker, which provide anchoring sites to the metal ions of the metal precursors. Due to the highly oxidising nature of these toxic ions, a redox reaction takes place between the framework metal ions and toxic metal ions, which is explained by an electron paramagnetic resonance study. This is the first report to synthesize non-toxic, as well as useful, NPs of As and Cr from their highly toxic ions within the cavities of a PCP for remediation of the toxic waste stream and contaminated waste water.

Biosynthesis of silver nanoparticles using Bacillus subtilis EWP-46 cell-free extract and evaluation of its antibacterial activity.

PubMed

Velmurugan, Palanivel; Iydroose, Mahudunan; Mohideen, Mohmed Hanifa Abdul Kader; Mohan, Thankiah Selva; Cho, Min; Oh, Byung-Taek

2014-08-01

This study highlights the ability of nitrate-reducing Bacillus subtilis EWP-46 cell-free extract used for preparation of silver nanoparticles (AgNPs) by reduction of silver ions into nano silver. The production of AgNPs was optimized with several parameters such as hydrogen ion concentration, temperature, silver ion (Ag(+) ion) and time. The maximum AgNPs production was achieved at pH 10.0, temperature 60 °C, 1.0 mM Ag(+) ion and 720 min. The UV-Vis spectrum showed surface plasmon resonance peak at 420 nm, energy-dispersive X-ray spectroscopy (SEM-EDX) spectra showed the presence of element silver in pure form. Atomic force microscopy (AFM) and transmission electron microscopy images illustrated the nanoparticle size, shape, and average particle size ranging from 10 to 20 nm. Fourier transform infrared spectroscopy provided the evidence for the presence of biomolecules responsible for the reduction of silver ion, and X-ray diffraction analysis confirmed that the obtained nanoparticles were in crystalline form. SDS-PAGE was performed to identify the proteins and its molecular mass in the purified nitrate reductase from the cell-free extract. In addition, the minimum inhibitory concentration and minimum bactericidal concentration of AgNPs were investigated against gram-negative (Pseudomonas fluorescens) and gram-positive (Staphylococcus aureus) bacteria.

Synthesis of non-toxic As and Cr nanoparticles through redox activity of highly flexible layered coordination polymer of Ni(II)

NASA Astrophysics Data System (ADS)

Agarwal, Rashmi A.

2018-03-01

A simple method for the sequestration of As(III) and Cr(VI) from water has been demonstrated by utilizing a highly flexible porous coordination polymer (PCP) of Ni(II) in its as synthesized form or without solvent removal. This PCP reduces the high toxicity of As(III) and Cr(VI) ions into non-toxic As(0) and Cr/Cr2O3/CrO2 (zero, tri and tetravalent) nanoparticles (NPs) within its pores, and this is characterized by powder x-ray diffraction, x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. The high functionality of this polymer is due to the presence of monodentate carboxylate groups of a benzenetricarboxylate linker, which provide anchoring sites to the metal ions of the metal precursors. Due to the highly oxidising nature of these toxic ions, a redox reaction takes place between the framework metal ions and toxic metal ions, which is explained by an electron paramagnetic resonance study. This is the first report to synthesize non-toxic, as well as useful, NPs of As and Cr from their highly toxic ions within the cavities of a PCP for remediation of the toxic waste stream and contaminated waste water.

Hydroxyapatite-silver nanoparticles coatings on porous polyurethane scaffold.

PubMed

Ciobanu, Gabriela; Ilisei, Simona; Luca, Constantin

2014-02-01

The present paper is focused on a study regarding the possibility of obtaining hydroxyapatite-silver nanoparticle coatings on porous polyurethane scaffold. The method applied is based on a combined strategy involving hydroxyapatite biomimetic deposition on polyurethane surface using a Supersaturated Calcification Solution (SCS), combined with silver ions reduction and in-situ crystallization processes on hydroxyapatite-polyurethane surface by sample immersing in AgNO3 solution. The morphology, composition and phase structure of the prepared samples were characterized by scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray diffraction (XRD), UV-Vis spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. The data obtained show that a layer of hydroxyapatite was deposited on porous polyurethane support and the silver nanoparticles (average size 34.71 nm) were dispersed among and even on the hydroxyapatite crystals. Hydroxyapatite/polyurethane surface acts as a reducer and a stabilizing agent for silver ions. The surface plasmon resonance peak in UV-Vis absorption spectra showed an absorption maximum at 415 nm, indicating formation of silver nanoparticles. The hydroxyapatite-silver polyurethane scaffolds were tested against Staphylococcus aureus and Escherichia coli and the obtained data were indicative of good antibacterial properties of the materials. © 2013.

Investigations on surface chemical analysis using X-ray photoelectron spectroscopy and optical properties of Dy3+-doped LiNa3P2O7 phosphor

NASA Astrophysics Data System (ADS)

Munirathnam, K.; Dillip, G. R.; Chaurasia, Shivanand; Joo, S. W.; Deva Prasad Raju, B.; John Sushma, N.

2016-08-01

Near white-light emitting LiNa3P2O7:Dy3+ phosphors were prepared by a conventional solid-state reaction method. The orthorhombic crystal structure of the phosphors was confirmed using X-ray diffraction (XRD), and the valence states of the surface elements were determined from the binding energies of Li 1s, O 1s, Na 1s, P 2p, and Dy 3d by X-ray photoelectron spectroscopy (XPS). Attenuated total reflectance (ATR) - Fourier transform infrared (FT-IR) spectroscopy was employed to identify the pyrophosphate groups in the phosphors. Diffuse reflectance spectra (DRS) show the absorption bands of the Dy3+ ions in the host material. Intense blue (481 nm) and yellow (575 nm) emissions were obtained at an excitation wavelength of 351 nm and are attributed to the 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 transitions of Dy3+ ions, respectively. The combination of these two intense bands generates light emission in the near-white region of the chromaticity diagram.

Crystallographic site swapping of La3+ ion in BaA'LaTeO6 (A' = Na, K, Rb) double perovskite type compounds: diffraction and photoluminescence evidence for the site swapping.

PubMed

Phatak, R; Gupta, S K; Krishnan, K; Sali, S K; Godbole, S V; Das, A

2014-02-28

Double perovskite type compounds of the formula BaA'LaTeO6 (A' = Na, K, Rb) were synthesized by solid state route and their crystal structures were determined by Rietveld analysis using powder X-ray diffraction and neutron diffraction data. Na compound crystallizes in the monoclinic system with P2₁/n space group whereas, K and Rb compounds crystallize in Fm3m space group. All the three compounds show rock salt type ordering at B site. Crystal structure analysis shows that La ion occupies A site in Na compound whereas, it occupies B site in K and Rb compounds according to the general formula of AA'BB'O6 for a double perovskite type compound. Effect of this crystallographic site swapping of the La ion was also observed in the photoluminescence study by doping Eu(3+) in La(3+) site. The large decrease in the intensity of the electric dipole ((5)D0-(7)F2) transition in the Rb compound compared to the Na compound indicates that Eu(3+) ion resides in the centrosymmetric octahedral environment in the Rb compound.

IDATEN and G-SITENNO: GUI-assisted software for coherent X-ray diffraction imaging experiments and data analyses at SACLA.

PubMed

Sekiguchi, Yuki; Yamamoto, Masaki; Oroguchi, Tomotaka; Takayama, Yuki; Suzuki, Shigeyuki; Nakasako, Masayoshi

2014-11-01

Using our custom-made diffraction apparatus KOTOBUKI-1 and two multiport CCD detectors, cryogenic coherent X-ray diffraction imaging experiments have been undertaken at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility. To efficiently perform experiments and data processing, two software suites with user-friendly graphical user interfaces have been developed. The first is a program suite named IDATEN, which was developed to easily conduct four procedures during experiments: aligning KOTOBUKI-1, loading a flash-cooled sample into the cryogenic goniometer stage inside the vacuum chamber of KOTOBUKI-1, adjusting the sample position with respect to the X-ray beam using a pair of telescopes, and collecting diffraction data by raster scanning the sample with X-ray pulses. Named G-SITENNO, the other suite is an automated version of the original SITENNO suite, which was designed for processing diffraction data. These user-friendly software suites are now indispensable for collecting a large number of diffraction patterns and for processing the diffraction patterns immediately after collecting data within a limited beam time.

Dynamical diffraction imaging (topography) with X-ray synchrotron radiation

NASA Technical Reports Server (NTRS)

Kuriyama, M.; Steiner, B. W.; Dobbyn, R. C.

1989-01-01

By contrast to electron microscopy, which yields information on the location of features in small regions of materials, X-ray diffraction imaging can portray minute deviations from perfect crystalline order over larger areas. Synchrotron radiation-based X-ray optics technology uses a highly parallel incident beam to eliminate ambiguities in the interpretation of image details; scattering phenomena previously unobserved are now readily detected. Synchrotron diffraction imaging renders high-resolution, real-time, in situ observations of materials under pertinent environmental conditions possible.

Development of Thin Films as Potential Structural Cathodes to Enable Multifunctional Energy-Storage Structural Composite Batteries for the U.S. Army’s Future Force

DTIC Science & Technology

2011-09-01

glancing angle X - ray diffraction (GAXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemical...Emission SEM FWHM full width at half maximum GAXRD glancing angle X - ray diffraction H3COCH2CH2OH 2-methoxyethanol LiMn2O4 lithium manganese oxide...were characterized by scanning electron microscopy (SEM), X - ray diffraction (XRD), and atomic force microscopy (AFM). In addition,

A novel extended architecture with 4 6·6 4 topology based on mixed-valence Wells-Dawson arsenotungstate and mixed-ligand Cu(I) units

NASA Astrophysics Data System (ADS)

Tong, Ruizhan; Ren, Xiaoyu; Li, Zuoxi; Liu, Bin; Hu, Huaiming; Xue, Ganglin; Fu, Feng; Wang, Jiwu

2010-09-01

A novel inorganic-organic hybrid compound based on mixed-valence Wells-Dawson arsenotungstate and mixed-ligand Cu(I) units, Cu 8I(imi) 4(bpy) 6(H 2O)[As 2VW 2VW 16VlO 62]·2H 2O ( 1) (bpy=4,4'-bipydine; imi=imidazole), has been hydrothermally synthesized and characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, luminescent spectrum and single crystal X-ray diffraction. Single-crystal X-ray diffraction revealed that four terminal and three bridging oxygen atoms of the Wells-Dawson cluster are coordinated to Cu(I) ions and form an unprecedented hepta-supporting polyoxometalate. The functionalized arsenotungstates are further connected by two kinds of tridentate linkers, Imi-Cu-(bpy)-Cu-(bpy)-Cu-(bpy)-Cu-Imi and Imi-Cu-(bpy)-Cu-(bpy)-Cu-H 2O, to construct a 3D framework with 4 6·6 4 topology. The hybrid material has an intense emission at about 397 nm.

N-donor co-ligands driven two new Co(II)- coordination polymers with bi- and trinuclear units: Crystal structures, and magnetic properties

NASA Astrophysics Data System (ADS)

Zhou, Zhi-Hang; Han, Min-Le; Wu, Ya-Pan; Dong, Wen-Wen; Li, Dong-Sheng; Lu, Jack Y.

2016-10-01

Two new Co(II) coordination polymers(CPs), namely [Co2(bpe)2(Hbppc)]n (1) and [Co3(μ3-OH)(bppc)(bpm)(H2O)]·3H2O (2) (H5bppc=biphenyl-2,4,6,3‧,5‧-pentacarboxylic acid, bpe=1,2-bis(4-pyridyl)ethene, bpm=bis(4-pyridyl)amine), have been obtained and characterized by elemental analysis, single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), IR spectra and thermogravimetric analysis (TGA). 1 shows a binodal (4,6)-connected fsc net with a (44·610·8)(44·62) topology, while 2 shows a binodal (5,7)-connected 3D network based on trinuclear [Co3(μ3-OH)]5+ units with unusual (3.46.52.6)(32.46.57.65.7) topology. Variable-temperature magnetic susceptibility measurements reveals that complex 1 shows ferromagnetic interactions between the adjacent Co(II) ions, whereas 2 is a antiferromagnetic system.

Crystallization and preliminary X-ray crystallographic analysis of the tRNA-specific adenosine deaminase from Streptococcus pyogenes

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

Ku, Min-Je; Lee, Won-Ho; Biotechnology and Genetic Engineering, Korea University, Seoul 136-701

2005-04-01

The tRNA-specific adenosine deaminase from the pathogenic bacteria S. pyogenes has been overexpressed and crystallized. The tRNA-specific adenosine deaminase from the pathogenic bacteria Streptococcus pyogenes (spTAD) has been overexpressed in Escherichia coli and crystallized in the presence of Zn{sup 2+} ion at 295 K using ammonium sulfate as a precipitant. Flash-cooled crystals of spTAD diffracted to 2.0 Å using 30%(v/v) glycerol as a cryoprotectant. X-ray diffraction data have been collected to 2.0 Å using synchrotron radiation. The crystal belongs to the tetragonal space group P4{sub 2}2{sub 1}2, with unit-cell parameters a = b = 81.042, c = 81.270 Å. Themore » asymmetric unit contains one subunit of spTAD, with a corresponding crystal volume per protein weight (V{sub M}) of 3.3 Å{sup 3} Da{sup −1} and a solvent content of 62.7%.« less

Direct observation of lithium polysulfides in lithium-sulfur batteries using operando X-ray diffraction

NASA Astrophysics Data System (ADS)

Conder, Joanna; Bouchet, Renaud; Trabesinger, Sigita; Marino, Cyril; Gubler, Lorenz; Villevieille, Claire

2017-06-01

In the on going quest towards lithium-battery chemistries beyond the lithium-ion technology, the lithium-sulfur system is emerging as one of the most promising candidates. The major outstanding challenge on the route to commercialization is controlling the so-called polysulfide shuttle, which is responsible for the poor cycling efficiency of the current generation of lithium-sulfur batteries. However, the mechanistic understanding of the reactions underlying the polysulfide shuttle is still incomplete. Here we report the direct observation of lithium polysulfides in a lithium-sulfur cell during operation by means of operando X-ray diffraction. We identify signatures of polysulfides adsorbed on the surface of a glass-fibre separator and monitor their evolution during cycling. Furthermore, we demonstrate that the adsorption of the polysulfides onto SiO2 can be harnessed for buffering the polysulfide redox shuttle. The use of fumed silica as an electrolyte additive therefore significantly improves the specific charge and Coulombic efficiency of lithium-sulfur batteries.

Grazing incidence synchrotron X-ray diffraction of marbles consolidated with diammonium hydrogen phosphate treatments: non-destructive probing of buried minerals

NASA Astrophysics Data System (ADS)

Possenti, Elena; Colombo, Chiara; Conti, Claudia; Gigli, Lara; Merlini, Marco; Plaisier, Jasper Rikkert; Realini, Marco; Gatta, G. Diego

2018-05-01

Diammonium hydrogen phosphate (DAP)-based consolidating treatments react with carbonatic stones and form calcium phosphates phases, whose composition depends on the availability of free calcium ions. In this work, an innovative non-destructive approach based on grazing incidence X-ray diffraction (GIXRD) with synchrotron radiation (SR) is used to investigate DAP-treated Carrara marble specimens and to study the influence of the substrate composition on the crystallization of calcium phosphate phases. The outcomes indicate that the presence of compositional micro-heterogeneity of Carrara marble favours the formation of specific phases. Dicalcium phosphate dihydrate, a calcium phosphate with a low Ca/P molar ratio, is formed on carbonatic phases with a low Ca amount, such as dolomite grains and Mg-containing veins. Furthermore, this study highlights the potentialities of SR-GIXRD as a powerful non-destructive tool for the diagnostic of Cultural Heritage objects since it allows investigating the conservation history of stone materials and their interaction with the environment.

Luminescence and antibacterial studies of silver nanoparticles using the esterases-containing latex of E. Tirucalli plant via green route

NASA Astrophysics Data System (ADS)

Sudheerkumar, K. H.; Dhananjaya, N.; Reddy Yadav, L. S.

2016-04-01

Silver nanoparticles (Ag NPs) synthesized from silver nitrate solutions using the esterase-containing latex of the E. Tirucalli plant widely found in a large region in Karnataka, India. Plant-mediated synthesis of nanoparticles is a green chemistry approach that intercom-nects nanotechnology and plant biotechnology. The effect of extract concentration, contact time, and temperature on the reaction rate and the shape of the Ag nanoparticles was investigated. The nanoparticles have been characterized by powder X-ray diffraction, UV-visible spectroscopy, photoluminescence spectroscopy and morphology by scanning electron microscope, transmission electron microscopy, as a function of the ratio of silver ions to reducing agent molecules. Powder X-ray diffraction patterns show that the crystal structure obtained is face-centered cubic (fcc). The morphology of the silver nanoparticle was uniform with well-distributed elliptical particles with a range from 15 to 25nm. Ag NPs exhibit significant antibacterial activity against Bacillus cereus using the agar well diffusion method.

CMC-coated Fe3O4 nanoparticles as new MRI probes for hepatocellular carcinoma

NASA Astrophysics Data System (ADS)

Sitthichai, Sudarat; Pilapong, Chalermchai; Thongtem, Titipun; Thongtem, Somchai

2015-11-01

Pure Fe3O4 nanoparticles and Fe3O4 magnetic nanoparticles (MNPs) coated with carboxymethyl cellulose (CMC) were successfully prepared by co-precipitating of FeCl2·4H2O and FeCl3·6H2O in the solutions containing ammonia at 80 °C for 3 h. Phase, morphology, particle-sized distribution, surface chemistry, and weight loss were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) including high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. In this research, CMC-coated Fe3O4 MNPs consisting of Fe2+ and Fe3+ ions with 543.3-mM-1 s-1 high relaxivity were detected and were able to be used for magnetic resonance imaging (MRI) application with very good contrast for targeting hepatocellular carcinoma (HCC) without any further vectorization.

Nd: YAG laser irradiation effects on structural and magnetic properties of Ni1+xZrxFe2-2xO4 nanoparticles

NASA Astrophysics Data System (ADS)

Saraf, Tukaram S.; Kounsalye, Jitendra S.; Birajdar, Shankar D.; Shamkuwar, N. R.

2018-05-01

The effect of 112 mJ Nd: YAG laser irradiation on structural, morphological, infrared and magnetic properties of Ni1+xZrxFe2-2xO4 spinel ferrite nanoparticles has been systematically investigated in the present work. The sol-gel auto combustion synthesis method was successfully executed for the synthesis of the present system. All the samples were characterized by X-ray diffraction technique (XRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR) technique. The magnetic properties of the present samples were measured by pulse field hysteresis loop technique. All the properties were measured for laser irradiated samples as well, to understand the effect of irradiation on the properties. The single-phase cubic spinel structure was confirmed by X-ray diffraction patterns of all samples and the disordered structure was observed for irradiated samples. The two principle absorption bands in IR spectra also confirm the formation of the spinel structure. Spherical and agglomerated morphology was observed for Zr4+ substituted nickel ferrite, whereas scratched morphology was observed for the irradiated samples. The grain size confirms the nanocrystalline nature, the crystallite size also evident the same. The magnetic parameters decreased after Zr4+ ion doping and strongly influenced by the irradiation.

Simultaneous X-ray fluorescence and scanning X-ray diffraction microscopy at the Australian Synchrotron XFM beamline

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

Jones, Michael W. M.; Phillips, Nicholas W.; van Riessen, Grant A.

2016-08-11

Owing to its extreme sensitivity, quantitative mapping of elemental distributionsviaX-ray fluorescence microscopy (XFM) has become a key microanalytical technique. The recent realisation of scanning X-ray diffraction microscopy (SXDM) meanwhile provides an avenue for quantitative super-resolved ultra-structural visualization. The similarity of their experimental geometries indicates excellent prospects for simultaneous acquisition. Here, in both step- and fly-scanning modes, robust, simultaneous XFM-SXDM is demonstrated.

An Excel Spreadsheet for a One-Dimensional Fourier Map in X-ray Crystallography

ERIC Educational Resources Information Center

Clegg, William

2004-01-01

The teaching of crystal structure determination with single-crystal X-ray diffraction at undergraduate level faces numerous challenges. Single-crystal X-ray diffraction is used in a vast range of chemical research projects and forms the basis for a high proportion of structural results that are presented to high-school, undergraduate, and graduate…

Laser-induced Multi-energy Processing in Diamond Growth

DTIC Science & Technology

2012-05-01

microscopy (SEM) and energy dispersive X - ray (EDX) measurements, Drs. Yi Liu and Shah Valloppilly from Nebraska Center for Materials and Nanoscience...NCMN) at UNL for help on X - Ray diffraction (XRD) measurements, and Professor Steve W. Martin and Dr. Young Sik Kim from the Department of Material...spectroscopy and X - ray diffraction ................... 62 4.4 Conclusions

Two-dimensional time-resolved X-ray diffraction study of liquid/solid fraction and solid particle size in Fe-C binary system with an electrostatic levitator furnace

NASA Astrophysics Data System (ADS)

Yonemura, M.; Okada, J.; Watanabe, Y.; Ishikawa, T.; Nanao, S.; Shobu, T.; Toyokawa, H.

2013-03-01

Liquid state provides functions such as matter transport or a reaction field and plays an important role in manufacturing processes such as refining, forging or welding. However, experimental procedures are significantly difficult for an observation of solidification process of iron and iron-based alloys in order to identify rapid transformations subjected to fast temperature evolution. Therefore, in order to study the solidification in iron and iron-based alloys, we considered a combination of high energy X-ray diffraction measurements and an electrostatic levitation method (ESL). In order to analyze the liquid/solid fraction, the solidification of melted spherical specimens was measured at a time resolution of 0.1 seconds during rapid cooling using the two-dimensional time-resolved X-ray diffraction. Furthermore, the observation of particle sizes and phase identification was performed on a trial basis using X-ray small angle scattering with X-ray diffraction.

Imaging single cells in a beam of live cyanobacteria with an X-ray laser.

PubMed

van der Schot, Gijs; Svenda, Martin; Maia, Filipe R N C; Hantke, Max; DePonte, Daniel P; Seibert, M Marvin; Aquila, Andrew; Schulz, Joachim; Kirian, Richard; Liang, Mengning; Stellato, Francesco; Iwan, Bianca; Andreasson, Jakob; Timneanu, Nicusor; Westphal, Daniel; Almeida, F Nunes; Odic, Dusko; Hasse, Dirk; Carlsson, Gunilla H; Larsson, Daniel S D; Barty, Anton; Martin, Andrew V; Schorb, Sebastian; Bostedt, Christoph; Bozek, John D; Rolles, Daniel; Rudenko, Artem; Epp, Sascha; Foucar, Lutz; Rudek, Benedikt; Hartmann, Robert; Kimmel, Nils; Holl, Peter; Englert, Lars; Duane Loh, Ne-Te; Chapman, Henry N; Andersson, Inger; Hajdu, Janos; Ekeberg, Tomas

2015-02-11

There exists a conspicuous gap of knowledge about the organization of life at mesoscopic levels. Ultra-fast coherent diffractive imaging with X-ray free-electron lasers can probe structures at the relevant length scales and may reach sub-nanometer resolution on micron-sized living cells. Here we show that we can introduce a beam of aerosolised cyanobacteria into the focus of the Linac Coherent Light Source and record diffraction patterns from individual living cells at very low noise levels and at high hit ratios. We obtain two-dimensional projection images directly from the diffraction patterns, and present the results as synthetic X-ray Nomarski images calculated from the complex-valued reconstructions. We further demonstrate that it is possible to record diffraction data to nanometer resolution on live cells with X-ray lasers. Extension to sub-nanometer resolution is within reach, although improvements in pulse parameters and X-ray area detectors will be necessary to unlock this potential.

A preliminary X-ray diffraction study of the laccase from Coriolus zonatus in the native state

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

Lyashenko, A. V.; Zhukhlistova, N. E.; Stepanova, E. V.

2006-03-15

The copper-containing enzyme laccase is involved, owing to its oxidase activity, in the biodegradation of lignins-one of the most important bioconversion processes. On the basis of the X-ray diffraction data for the laccase from Coriolus zonatus, the spatial structure of this enzyme is determined with a resolution of 3.2 A. R and R{sub free} are 0.2347 and 0.2976, respectively, and the rms deviations of the bond lengths and the bond angles are 0.009 and 1.547 A, respectively. The three-domain structure of the laccase from Coriolus zonatus is confirmed, where each domain is represented by a protein from the cupredoxin family.more » The spatial organization of the active center of the protein is established. The mononuclear center contains a copper ion Cu(1) with the atoms of S{sub C}ys453, ND1{sub H}is395, and ND1{sub H}is458 ligands. The trinuclear center is formed by copper ions Cu(2), Cu(3), and Cu(4), surrounded by ligands of eight nitrogen atoms of the histidines of the first and third domains of the protein His66, His109, His454, His111, His400, His452, His64, and His398. The Cu(1) ion is located at distances of 11.84 and 13.22 A from the Cu(2) and Cu(3) ions, respectively. The distance between the Cu(2) and Cu(3) ions is 5.14 A and the Cu(4)-Cu(2) and Cu(4)-Cu(3) distances are 4.75 and 4.41 A, respectively.« less

Characterization of carbon ion implantation induced graded microstructure and phase transformation in stainless steel

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

Feng, Kai; Wang, Yibo; Li, Zhuguo, E-mail: lizg@sjtu.edu.cn

Austenitic stainless steel 316L is ion implanted by carbon with implantation fluences of 1.2 × 10{sup 17} ions-cm{sup −} {sup 2}, 2.4 × 10{sup 17} ions-cm{sup −} {sup 2}, and 4.8 × 10{sup 17} ions-cm{sup −} {sup 2}. The ion implantation induced graded microstructure and phase transformation in stainless steel is investigated by X-ray diffraction, X-ray photoelectron spectroscopy and high resolution transmission electron microscopy. The corrosion resistance is evaluated by potentiodynamic test. It is found that the initial phase is austenite with a small amount of ferrite. After low fluence carbon ion implantation, an amorphous layer and ferrite phase enrichedmore » region underneath are formed. Nanophase particles precipitate from the amorphous layer due to energy minimization and irradiation at larger ion implantation fluence. The morphology of the precipitated nanophase particles changes from circular to dumbbell-like with increasing implantation fluence. The corrosion resistance of stainless steel is enhanced by the formation of amorphous layer and graphitic solid state carbon after carbon ion implantation. - Highlights: • Carbon implantation leads to phase transformation from austenite to ferrite. • The passive film on SS316L becomes thinner after carbon ion implantation. • An amorphous layer is formed by carbon ion implantation. • Nanophase precipitate from amorphous layer at higher ion implantation fluence. • Corrosion resistance of SS316L is improved by carbon implantation.« less

JPRS Report, Science & Technology, Japan, Selections from Future Industrial Technology Symposium.

DTIC Science & Technology

1988-08-01

pyrolyzed graphite ( HOPG ). X-ray diffraction photos of the biaxially stretched PPV films indicate that the films have been plane-oriented. It is...CRYSTALS OF TWO-DIMENSIONALLY CROSS-LINKED POLYMERS PRODUCED 8 ION-CROSSLINKING POLYMER COMPACTS EVALUATED 12 RECENT PROGRESS IN SYNTHETIC METALS...derived from 2,5-thienylene bis(methylene dimethyl sulfonium bromide). Highly conducting graphite films also have been obtained by pyrolysis of PPV and

Synthesis, Structure and Antitumour Properties of a New 1,2-Propylenediaminetetraacetate-Ruthenium(III) Compound

PubMed Central

Vilaplana, R.; Romero, M. A.; Quirós, M.; Salas, J. M.

1995-01-01

A novel complex formed by ruthenium (III) and the sequestering ligand 1,2-propylenediaminetetraacetic acid (PDTA) has been synthetized and characterized. The structure of the monomeric compound, studied by X-ray diffraction , shows an almost symmetric octahedral geometry around the metal ion, with two chlorine atoms in a cis conformation. The antitumour activity against a variety of murine and human cancers is reported. PMID:18472768

Surface and biological evaluation of hydroxyapatite-based coatings on titanium deposited by different techniques.

PubMed

Massaro, C; Baker, M A; Cosentino, F; Ramires, P A; Klose, S; Milella, E

2001-01-01

Hydroxyapatite coatings have been deposited on titanium cp by plasma spray, sol-gel, and sputtering techniques for dental implant applications. The latter two techniques are of current interest, as they allow coatings of micrometer dimensions to be deposited. Coating morphology, composition, and structure have been investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). All coatings were homogeneous and exhibited a rough morphology suitable for implant applications. The sputtered (after annealing), plasma spray, and sol-gel coatings all showed diffraction peaks corresponding to hydroxyapatite. The surface contaminants were observed to be different for the different coating types. The sputtered coatings were found to have a composition most similar to hydroxyapatite; the sol-gel deposits also showed a high concentration of hydroxyl ions. A discrepancy in the Ca/P ratio was observed for the plasma spray coatings, and a small concentration of carbonate ions was found in the sputter-deposited coatings. The in vitro cell-culture studies using MG63 osteoblast-like cells demonstrated the ability of cells to proliferate on the materials tested. The sol-gel coating promotes higher cell growth, greater alkaline phosphatase activity, and greater osteocalcin production compared to the sputtered and plasma-sprayed coatings. Copyright 2001 John Wiley & Sons, Inc.

Structure and electrical properties of intergrowth bismuth layer-structured Bi4Ti3O12-CaBi4Ti4O15 ferroelectric ceramics

NASA Astrophysics Data System (ADS)

Choi, Gi Ppeum; Cho, Sam Yeon; Bu, Sang Don

2016-09-01

Pb-free ferroelectric Bi4Ti3O12-CaBi4Ti4O15 (BIT-CBT) ceramics were manufactured using a solid-state reaction method. Structural analysis by using X-ray diffraction confirmed the presence of a second phase of Bi2Ti2O7, and the surface depth X-ray diffraction analysis revealed that this phase existed only on the surface. This second phase appears to have been caused by the volatilization of Bi ions at high sintering temperatures. For resolution of the issue of volatilization of Bi ions and manufacture of BIT-CBT ceramics with a single phase, Bi2O3 powder was added to the BIT-CBT mixture, and a powder-bed method, in which pellets were covered with BIT-CBT powder, was used to manufacture the ceramic. The piezoelectric coefficient of the single-phase BIT-CBT ceramics was 12.4 pC/N while the residual polarization and the coercive electric field were 11.3 μC/cm2, and 125 kV/cm, respectively. The results suggest that single-phase BIT-CBT ceramics are suitable for the manufacture of elements incorporating these electrical characteristics.

Structural, spectroscopic, and magnetic properties of Eu3+-doped GdVO4 nanocrystals synthesized by a hydrothermal method.

PubMed

Szczeszak, Agata; Grzyb, Tomasz; Śniadecki, Zbigniew; Andrzejewska, Nina; Lis, Stefan; Matczak, Michał; Nowaczyk, Grzegorz; Jurga, Stefan; Idzikowski, Bogdan

2014-12-01

New interesting aspects of the spectroscopic properties, magnetism, and method of synthesis of gadolinium orthovanadates doped with Eu(3+) ions are discussed. Gd(1-x)Eu(x)VO4 (x = 0, 0.05, 0.2) bifunctional luminescent materials with complex magnetic properties were synthesized by a microwave-assisted hydrothermal method. Products were formed in situ without previous precipitation. The crystal structures and morphologies of the obtained nanomaterials were analyzed by X-ray diffraction and transmission and scanning electron microscopy. Crystallographic data were analyzed using Rietveld refinement. The products obtained were nanocrystalline with average grain sizes of 70-80 nm. The qualitative and quantitative elemental composition as well as mapping of the nanocrystals was proved using energy-dispersive X-ray spectroscopy. The spectroscopic properties of red-emitting nanophosphors were characterized by their excitation and emission spectra and luminescence decays. Magnetic measurements were performed by means of vibrating sample magnetometry. GdVO4 and Gd0.8Eu0.2VO4 exhibited paramagnetic behavior with a weak influence of antiferromagnetic couplings between rare-earth ions. In the substituted sample, an additional magnetic contribution connected with the population of low-lying excited states of europium was observed.