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The protein elicitor from Alternaria tenuissima (PeaT1) presented excellent thermotolerance and potential application in agriculture as a pesticide. Previous synchrotron radiation circular dichroism study demonstrated that the secondary structures in PeaT1 protein are reversible with temperature change. To further clarify the mechanism of its thermotolerance, synchrotron radiation small angle x-ray scattering (SAXS) technique was used to study the shape change of PeaT1 protein with temperature in this article. Ab initio structure restorations based on the SAXS data revealed that PeaT1 protein has a prolate shape with a P₂ symmetry axis along the prolate anisometric direction. With temperature increase, a gooseneck vase-like (25°C), to jug-like (55°C), then to oval (85°C) shape change can be found, and these shape changes are also approximately reversible with temperature decrease. PeaT1 protein contains two homogenous molecules, and each of them consists of F, NAC, T, and UBA domains. The structures of the four domains were predicted. Simulated annealing algorithm was used to superimpose the domain structures onto the SAXS shapes. It was found that all the structural domains have position rotation and translation with temperature change, but the NAC domains are relatively stable, playing a role of frame. This shape change information provides clues for further exploring its biological function and application., (Copyright © 2012 Wiley Periodicals, Inc.)

Using the three slit collimation system with a divergent beam simplifies the design of a small angle X-ray scattering (SAXS) cameras and improves both flux and stability. To achieve the required low angle and a high spatial resolution, the collimation system must be optimized in the design and operation phases. Simulation of a slit divergent camera yields optimal distance between the beam defining slits and optimal distance between sample and detector at which the maximum SAXS resolution is achieved with a minimal parasitic scattering for any length of the SAXS camera. The narrower the beam defining slits and the longer the total camera length, the smaller the minimum resolvable angle and the higher the attainable resolution.

The computed tomography technique cannot easily be extended to diffraction enhanced imaging (DEI) because, while from DEI we may extract the refractive index gradient in one dimension, from the conventional CT reconstruction algorithm we may reconstruct only a scalar quantity. However, recently we showed that changing the direction of the scan axis, and collecting a set of data related to the three-dimensional distribution of the refractive index gradient of the sample, a CT image was obtained. The algorithm we used is based on the conventional CT algorithm but with a specific pre-processing of the projection data. The mathematical framework of the procedure and a simple CT experiment are presented and discussed.

A direct relationship between the x-ray intensity ratio and the concentration ratio for bulk and thin specimens has been established by use of a revised full-diffusion model of electron scattering. The suitable ionization cross section, the most important parameter influencing the accuracy of the calculated Cliff-Lorimer factors, has been found after comparing the experimental intensity ratio I(L)/I(K) of eight elements (from Ge to Sn) and I(M)/I(L) of six elements (from Sm to Bi) with the calculated values. The quantitative standardless EDS analysis of bulk samples obtained by this direct method is more satisfactory than the commercial indirect method which gives the composition through ZAF correction after calculating the intensity factors of pure elements. The quantitative standardless analysis of thin samples has been improved by the suitable cross section significantly. This method has been applied to the analysis of film on substrate either without any common element or with one common element (P-Si glass film on Si). It has also been used to calculate the intensity factors of pure bulk samples and the backscattering correction factor in Auger electron spectroscopy.

In this study, we present theoretical and experimental results regarding highly conductive modulation doped composition graded p-AlGaN/(AlN)/GaN multiheterostructures. Based on simulation results, several multiheterostructures were grown by metalorganic vapor phase epitaxy. Using high resolution x-ray diffraction and x-ray reflectometry, the abruptness of the AlGaN/AlN/GaN interfaces could be determined. Using electron holography, the energetic profile of the valence band could be measured, yielding important information about the vertical carrier transport in such multiheterostructures. The electrical properties of the samples were investigated by measuring the lateral (σL) and vertical (σV) conductivity, respectively. The free hole concentration of a sample optimized in terms of lateral conductivity was measured to be 1.2×1019 cm-3 (295 K) with a mobility of 7 cm2/V s, yielding a record σL of 13.7 (Ω cm)-1. Low temperature Hall measurements (77 K) proved the existence of a two-dimensional hole gas at the AlN/GaN interface, as the lateral conductivity could be increased to 30 (Ω cm)-1 and no carrier freeze out was observable. By substituting the p-GaN layer in a light emitting diode (LED) with an AlGaN/GaN multiheterostructure, the overall voltage drop could be reduced by more than 100 mV (j=65 A/cm2). Furthermore improved current spreading on the p-side of LEDs with integrated AlGaN/AlN/GaN multiheterostructures could be proved by μ-electroluminescence, respectively. [ABSTRACT FROM AUTHOR]

Thin YBa2Cu3O7-δ/La0.67Ca0.33MnO3/YBa2Cu3O7-δ (YBCO/LCMO/YBCO) trilayers on (001)-oriented SrTiO3 (STO) substrates were fabricated by magnetron sputtering technique. The trilayers are well c-axis oriented confirmed by x-ray diffraction. The surface and interface structure of the trilayers were investigated by grazing incident x-ray reflectivity. The results showed that there exists diffusion at the YBCO/LCMO interfaces with the diffusion length of several nanometers. The root-mean-square (rms) roughness of surface and interface in the trilayers varied with the thickness of YBCO layer. The rms roughness of surface was consistent with observation by atomic force microscopy. A further analysis indicated that the rms roughness was correlative to the misfit strain relaxation in film. [ABSTRACT FROM AUTHOR]

Doped topological insulators (TI) BiNdSe single crystals were prepared by the self-flux method. The phase structure, magnetic properties, and electrical transport properties of the samples were studied. The X-ray diffraction (XRD) patterns of the sample indicate an incorporation of Nd into the BiSe, and the crystal can be easily cleaved with silvery surface. The BiNdSe sample shows a giant magnetoresistance (MR) with different magnetic field. The positive magnetoresistance (MR) can reach 190 % at the field of 9 Tesla when the field is perpendicular to ab-plane of the crystal. In addition, at low magnetic fields, the MR exhibits a weak antilocalization (WAL) cusp. [ABSTRACT FROM AUTHOR]

Provides information on a study that examined the texture structure and the intermetallic compound formation in the unannealed and annealed tantalum/aluminum multilayer samples using two kinds of x-ray diffraction methods. Methodology of the study; Results and discussion on the study.

A new kind of magnesium based hydrogen storage alloy with highly developed surface (HDS) was prepared using the technique of mechanical alloying followed by alkali washing in this paper. The phase composition, morphology, hydrogen storage properties and mechanisms of the alloy thus prepared, named HDS Mg-Ni, were further investigated by multiple methods including X-ray diffraction, scanning electron microscope, Sieverts volumetric method and differential scanning calorimeter. The specific surface area, average pore size and pore volume of the alloy are 50.95 m 2 g −1 , 36.2 nm and 0.34 cc g −1 , respectively. Also, it was discovered that the HDS Mg-Ni powder takes in about 0.65 wt.% of hydrogen even at a low temperature of 323 K, at which the conventional Mg and Mg 2 Ni materials could not react with H 2 . It suggests that the highly developed surface remarkably improves the hydrogen storage properties at low temperatures. Besides, the synergistic effects between the HDS Mg-Ni powder and activated carbon(AC) on the improvement of low-temperature behaviors were discussed. The results showed that the addition of AC further improves the hydrogen capacity and absorption kinetics due to the increased specific surface area, providing easier and more paths for the diffusion of hydrogen into the alloy powder. [ABSTRACT FROM AUTHOR]

Three new complexes, [CdL(CHCOO)(HO)] ( I), CdLBr ( II), CdLI ( III), have been successfully synthesized by self-assembly of corresponding metal salts with ( E)-2-(3-(4-(1 H-imidazole-1-yl)styryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile (L). The structures of the complexes were determined by single crystal X-ray diffraction analysis (CIF file CCDC nos. 957831 ( I), 957792 ( II), 957832 ( III)). In complex I, central metal is six-coordinated and the crystal packing shows a 3D supramolecular framework. Complexes II and III display the similar 2D supramolecular structures in which the central metals are four-coordination. The luminescent properties were investigated. [ABSTRACT FROM AUTHOR]

Two new Zn(II) coordination complexes [ZnL(SCN)] ( I) and [ZnLCl] ( II) have been pre-pared by self-assembly of corresponding metal salts with ( E)-2-(3-(4-(1 H-imidazole-1-yl)styryl)-5,5-dimethylcyclohexo-2-enylidene) malononitrile (L) and characterized by IR spectrum, elemental analysis and single-crystal X-ray diffraction. Complexes I and II are two-dimensional (2D) networks with different topology structures. The luminescence properties were investigated. [ABSTRACT FROM AUTHOR]

Some new ( S)-1-aryl- N-(1-hydroxy-3-phenylpropan-2-yl)-5-methyl-1 H-1,2,3-triazole-4-carboxamides 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j have been synthesized and established by 1H and 13C NMR, IR, MS spectra, CHN analyses, and x-ray diffraction crystallography. The molecular conformation and packing is stabilized by interactions of intermolecular H-bond O2'-H2'···O1, O2-H2···O1' and intramolecular H-bond N4'-H4'N···N3', N4'-H4'N···O2', N4-H4N···N3, N4-H4N···O2. The two rings of five numbers were formed by H-bond in a molecular. [ABSTRACT FROM AUTHOR]

Ni0.5Co0.5Fe2O4(NCFO) nanoparticles were prepared by the chemical co-precipitation process using metal chloride, nitrate and acetate as precursor, after the precursors were annealed and then investigated in detail by employing X-ray diffraction (XRD), magnetic measurement and the bovine serum albumin (BSA) adsorption on the nanoparticles was analyzed by UV spectrophotometer at room temperature. XRD analysis indicates that all the as-prepared nanocrystals posses a pure cubic spinel structure. The saturation magnetization initially increases and then decreases with increasing annealing temperature, with a maximum value 67.19 emu/g at 950 °C. The coercivity also firstly increases and then decreases with increasing annealing temperature, with a maximum value of 828 Oe at 650°C. The as-prepared Ni0.5Co0.5Fe2O4nanoparticles exhibit a good adsorbing ability for BSA and the optimized adsorption is achieved for the Ni0.5Co0.5Fe2O4nanoparticles annealed at 750°C with grain size about 33.3 nm. [ABSTRACT FROM PUBLISHER]

In this work, a-plane GaN/ r-sapphire templates have been used to grow nonpolar a-plane ZnO films by pulsed laser deposition. The ZnO film growth temperature was varied in the range of 400°C to 600°C, and the effect of growth temperature on the properties of the ZnO thin films was investigated using x-ray diffraction, atomic force microscopy, photoluminescence (PL) spectroscopy, and Raman measurements. The results show that the crystal quality, surface morphology, strain states, and optical properties of a-plane ZnO films are strongly correlated with the deposition temperature. It is found that the crystallinity of the ZnO films gets better and the surface roughness decreases with increasing growth temperature. At a growth temperature of 600°C, the a-ZnO films display the best crystal quality with x-ray $$ (11\bar{2}0) $$ omega scan full-width at half-maximum values of 0.28° and 0.41° on axis $$ (11\bar{2}0) $$ at azimuth 0° and 90°, respectively. Furthermore, the PL spectrum measured at 83 K is dominated by neutral donor-bound excitons and free-electron-to-bound ( e- A) emission, and relatively intense LO-phonon replicas of ( e- A) have also been observed in the a-plane ZnO. The dominance of the free exciton and the appearance of its replicas strongly indicate the high quality of the film. [ABSTRACT FROM AUTHOR]

A new kind of magnesium based brazing alloy with a low brazing temperature of ∼450°C was developed for AZ31B. Correlative technological parameters were investigated to refine the structure of the bond region. The microstructure of the joints was observed by SEM equipped with an energy dispersive X-ray spectroscopy analysis system. The result showed that the microstructure of the joints contained the first separate-out phase (α-Mg), which dispersed in the bond region, and the tiny layered eutectic structure (α-Mg + MgZn). Water quenching supported high cooling rate and thus refined the eutectic structure. The typical fracture morphology and the X-ray diffraction fracture analysis showed that many dimples existed in the place of the first separate-out phase, and the fracture zone consisted of MgZn, Mg7Zn3 and Mg. The joints showed high strength in the tensile shear tests. [ABSTRACT FROM AUTHOR]

Abstract: The hydrogen storage and electrochemical properties of the Ti0.32Mn0.22Cr0.1V0.28Ni x (x =0, 0.05, 0.15, 0.2) alloys were investigated. XRD results revealed that the addition of Ni resulted in the formation of C14 Laves phase. With the increasing Ni content, the lattice parameter a of BCC phase and the lattice parameter a and c of C14 Laves phase decreased. The Ni addition reduced the hydrogen absorption/desorption capacities at gas solid reaction, but improved the electrochemical discharge capacity significantly. The maximum discharge capacity of 392mAhg−1 was obtained for the Ti0.32Mn0.22Cr0.1V0.28Ni0.15 alloy. Cycling measurement revealed that the discharge capacity of the Ti0.32Mn0.22Cr0.1V0.28Ni0.15 alloy degraded with the increasing cycle number, decreasing to 63% of the maximum discharge capacity after 100 cycles. Further improvement on the activation and cycle life of this alloy can be achieved by surface modification with 20wt.% LaNi3.55Co0.75Mn0.4Al0.3 addition. [Copyright &y& Elsevier]

Single phase of La1−xSrxCoO3 (LSCO) with 0.1 ≤ x ≤ 0.4 have been prepared by the solid-state reaction method. All samples have the R3̅c symmetry. There is no phase transition detected at the temperature range from 10 to 300 K. The variations of the local bond-lengths of Co—O in CoO6 octahedron and lattice parameter ar confirm that hole-doping stabilize the intermediate-spin (IS) state of Co ions. The magnetic phase diagram is well understood in terms of phase separation scenario. Qualitatively, hole-rich ferromagnetic (FM) clusters increasing in size and number with the increase in the concentration of Sr at the expensive of non-FM insulating matrix, and percolating at the vicinity of 0.15, are suggested to explain the onset of FM order and insulator–metal transition. In addition, the values of effective paramagnetic moment μeff also strongly prove the presence of IS spin state of Co in our system. Very small magnetoresistance (MR), 5% with 3 T magnetic field applied, is obtained. This MR response indicates that a distinct mechanism is likely to dominate in LSCO compared to that in mixed-valence manganites. [Copyright &y& Elsevier]

Annealing was carried out to produce Ag–Cu dual-nanophase composite by decomposing Ag–Cu supersaturated solid solution prepared by ball-milling. Differential scanning calorimetry, X-ray diffraction, and transmission electron microscopy were used to characterize the growth kinetics of the nanophase composite upon heating. The results show that bimodal growth kinetics is obeyed in the dual-nanophase system. The coarsening of the second phase of small volume fraction follows the cubic law of LSW theory, while the grain growth of matrix phase follows the kinetic equation of the grain growth of pure nanocrystalline metals. In both cases, the growth is controlled by grain boundary diffusion. [ABSTRACT FROM AUTHOR]

Methods to collect two-dimensional time-resolved x-ray diffraction patterns from surfaces/interfaces were developed. Reflection surface x-ray diffraction utilizing high brilliance x rays and a charge coupled device can achieve a time resolution as good as one second. Also, two-dimensional maps of reflectivity rocking curves can be recorded fast enough to monitor growth processes. These methods were demonstrated for the study of Ag and Pb films on Si (111)-(7×7) surfaces. [ABSTRACT FROM AUTHOR]

Single-phase potassium tantalate (KT) thin films with excellent film flatness and crystallinity have been synthesized on a tantalum substrate in 2.0 M KOH solution at 150°C by a hydrothermal-electrochemical method under a galvanostatic condition. A pyrochlore structure of the thin KT films was identified by XRD pattern analysis. The films show good adherence to the substrate and the film thickness could be as much as 2 μm. The electrical properties of the films were characterized through the determination of capacitance by electrochemical impedance spectroscopy at room temperature. Dielectric constants yielded from capacitance measurements have been calculated to have values higher than 300. The dependence of cell voltage on reaction time reflects the mechanism of film formation. The preparation conditions and morphology of the films were consistent with the proposed film formation mechanism. [ABSTRACT FROM AUTHOR]

We have investigated the structural properties and relaxation phenomenon of InGaN multiple quantum wells (QWs) on [formula] semipolar GaN templates grown on patterned (001) silicon substrates by selective area growth technique. Our studies by transmission electron microscopy and x-ray diffraction reciprocal space mapping reveal that QWs emitting light at 540 nm experience significant strain relaxation along the in-plane [formula] direction by the generation of an array of basal stacking faults (BSF). The generation of BSFs in 540 nm QWs could be an important factor limiting its luminescence efficiency. [ABSTRACT FROM AUTHOR]

Recently taking advantage of the novel diffraction-enhanced imaging (DEI) method, one very effective and practical phase contrast imaging technique—a new x-ray computed tomography scheme based on DEI (DEI-CT) showed promising results, really superior to those of conventional CT imaging. In this letter, we show that the application of the conventional CT reconstruction algorithm is not always satisfactory for the new DEI-CT imaging and a new mathematical framework for imaging reconstruction is presented. Experimental data collected at the Beijing synchrotron radiation facility are also discussed using the new algorithm. [ABSTRACT FROM AUTHOR]

Thin films of La0.39Pr0.24Ca0.37MnO3 (LPCMO) were epitaxially grown on 0.7PbMg1/3Nb2/3O3-0.3PbTiO3 (PMN-PT) substrates. These LPCMO films exhibited low-temperature persistent photoconductivity (PPC) when illuminated by a visible light of 532 nm. Not only the resistance but also PPC were modulated by electric fields across PMN-PT. Detailed analysis and in situ x-ray diffraction indicate that such modulations were mainly due to the change of lattice deformation by applied electric fields via converse piezoelectric effect. It was also found that light and strain influence the phase competition in different ways. [ABSTRACT FROM AUTHOR]