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Changes in the refractive index and thickness of amorphous As2S8 semiconductor film are observed under illumination, annealing–illumination, and annealing-illumination cycles. Properties of the As2S8 film are measured using techniques of prism coupler, x-ray diffraction spectra and Raman spectra. After light illumination the refractive index change in an as-deposited As2S8 film is one order of magnitude greater than that of an annealed As2S8 film, corresponding to ∼0.06 and ∼0.0057, respectively. Photoexpansions with a change in the relative film thickness of the as-deposited and annealed As2S8 film are nearly -3.5% and -2.1%, respectively, which exhibit the photodensification. The full reversibility of the photoinduced refractive index change is claimed on an annealed As2S8 film sample. [ABSTRACT FROM AUTHOR]

A new azido-bridged copper(II) complex with nitronyl nitroxide radicals Cu ( NITpPy)(N) ( NITpPy = 4-pyridyl-4,4,5,5-tetramethylimidaz-line-3-oxide-1-oxyl) has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in triclinic, space group $$P\bar 1$$, Z = 1. Crystal data: CHCuNO, M = 1084.71, a = 7.1334(11), b = 13.718(2), c = 14.136(2) Å, α = 88.425(2)°, β = 78.528(2)°, γ = 87.390(2)°, V = 1354.0(4) Å, D = 1.330 g/cm, μ(Mo Kα) = 0.472 mm, F(000) = 571, R = 0.0735 and wR = 0.1140 for 4962 observed reflections with I > 2σ( I). The X-ray analysis reveals that Cu(II) ion resides in a perfect octahedron center. The units of [Cu ( NITpPy)(N)] were connected as 3-D network structure by the nonclassical intermolecular H-bonds. [ABSTRACT FROM AUTHOR]

Two new complexes [Co(NIT-1′-MeBzIm)(Dca)] ( I) and [Ni(NIT-1′-MeBzIm)(Dca)(HO) · NO · HO ( II) (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; Dca = N(CN)) were prepared and structurally characterized by single-crystal X-ray diffraction. Relevant crystallographic parameters are as follows: monoclinic, P2 space group, Z = 4; crystal data: CHNOCo, M = 765.71, a = 14.343(4), b = 14.322(4), c = 18.626(5) Å, β = 105.956(3)° for I. Orthorhombic Pna2 space group, Z = 4; crystal data: CHNONi, M = 797.49, a = 24.426(4), b = 11.0326(18), c = 13.980(2)Å for II. The X-ray analysis reveals that Co ion and Ni ion resides in a approximate sdistorted octahedron center. In I, the complex was linked by intermolecular hydrogen bonds, resulting in a 1D chain configuration. In II, the complex was linked by intermolecular hydrogen bonds, resulting in a 2D network configuration. [ABSTRACT FROM AUTHOR]

A new manganese(II) complex [MnCl(NIT-1′-MeBzIm)] · 3HO (NIT-1′-MeBzIm = 2-{2′-[(l′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group C2/ c, Z = 4. Crystal data: CHClMnNO, M = 764.52, a = 17.261(3) Å, b = 21.317(4) Å, c = 11.744(2) Å, β = 108.464(2)°. The X-ray analysis reveals that Mn(II) atom is six-coordinated with a distorted octahedral geometry. The complex was linked by intermolecular hydrogen bonds, leading to a 2D network configuration. Magnetic investigation indicates the existence of interamolecular interactions is ferromagnetic with J = 1.11 cm. [ABSTRACT FROM AUTHOR]

Two nickel(II) complexes [Ni(NIT-l′-MeBzlrn)(Dca)] ( I, II) (NIT-l′-MeBzIm = 2-{2′-[(l′methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide) have been prepared and structurally characterized by single-crystal X-ray diffraction. They are structural epimers. The complexe crystallizes in monoclinic, space group P2/ n, Z = 4. Crystal data: CHNNiO, M = 765.49, a = 15.019(3), b = 18.803(4), c = 15.756(3) Å, β = 109.399(3)°, γ = 90° (I); a = 13.934(3), b = 11.046(2), c = 24.570(5) Å, β = 90.024(2)° (II). The X-ray analysis reveals that Ni ion resides in a distorted octahedral center. The complex was linked by intermolecular hydrogen bonds, resulting in a ID chain structure for I and a 2D network configuration for II. [ABSTRACT FROM AUTHOR]

The novel dinuclear cadmium(II) complex [Cd(NIT-1′-MeBzIm)(CHCOO)] ( I), where NIT-1′-MeBzIm = 2-{2′-[(1′-methyl)benzimidazolyl]}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, has been prepared and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in monoclinic crystal system, space group C2/ c, Z = 4. Crystal data: CHCdNO, M = 1035.66, a = 18.6492(16), b = 11.9605(10), c = 19.9208(17) Å, β = 92.1650(10)°. The X-ray analysis reveals that two Cd(II) atoms were bridged by two acetate groups to form a centrosymmetric Cd(II)-Cd(II) dinuclear entity, Cadmium atom is six-coordinated with a distorted octahedral geometry. The complex is linked by intermolecular hydrogen bonds leading to a 2D network configuration. Magnetic investigation indicates the existence of weak intramolecular interactions; i.e., the complex I is ferromagnetic with J = 1.97 cm. [ABSTRACT FROM AUTHOR]

We report the results of a synchrotron based X-ray diffraction study of bct-Fe2B under quasi-hydrostatic conditions from 0 to 50 GPa. Over this pressure range, no phase change or disproportionation has been observed. A weighted fit of the data to the Birch–Murnaghan equation of state yields a value of the bulk modulus, K, of 164±14 GPa and the first pressure derivative of the bulk modulus, K′, of 4.4±0.5. The compression is found to be anisotropic, with the a-axis being more incompressible than the c-axis. [Copyright &y& Elsevier]

X-ray diffraction measurements of tetragonal chalcopyrite cadmium germanium arsenide crystal are carried out over the range 25-450 °C. The collected patterns show that the powder neither yields a new phase nor structurally transforms to any other architecture. Accurate lattice parameters (including two lattice constants a and c, cell volume V, axial ratio k, and tetragonal distortion δ) are determined by means of Cohen's least square method. Polynomial fit approximation is adopted to quantitatively describe the temperature dependence of lattice parameters. These results are the groundwork that allows the evaluation of thermal expansion coefficients defined as αR = R-1(dR/dT) where R represents lattice parameters. The average thermal expansion coefficients are evaluated, 13.9 × 10-6 K-1 for αa and 2.8 × 10-6 K-1 for αc, respectively. It is also found that αa increases while αc decreases with temperature, which in consequence brings forth the large anisotropy of thermal expansion between the two main axes (a-axis and c-axis). Detailed discussion reveals that the anisotropy behavior is in tight association with the nearest neighboring bonds. Namely, the thermal expansion coefficient perpendicular to c-axis (αa) depends to a large extent on the ionic Cd-As bonds, while that parallel to c-axis (αc) depends on the covalent Ge-As bonds. Finally, the Grüneisen parameters at different temperatures are evaluated and also exhibit anisotropic behavior (γa > γc). It is found that γa is temperature-dependent and increases with temperature, while γc tends to be temperature-independent. [ABSTRACT FROM AUTHOR]

Abstract: Stress-induced martensitic transformation of as-sputtered and post-annealed Ti50.1Ni40.8Cu9.1 thin films was investigated using in-situ synchrotron X-ray diffraction (S-XRD) technique. For the as-deposited film, in-situ S-XRD analysis showed a martensitic transformation from parent phase to martensite during initial loading, followed by reorientation of martensite variants via detwinning. This detwinning process induced a strong 〈020〉 fiber texture along the loading direction and a strong 〈002〉 fiber texture perpendicular to the loading direction. For the 650°C annealed film, there is only elastic deformation, followed by a martensitic transformation during deformation. [Copyright &y& Elsevier]

Classification of stellar spectra from voluminous spectra is a very important and challenging task. In order to better classify stellar spectra, inspired by the principle of deep convolutional neural network (CNN), we propose a supervised algorithm for stellar spectra classification based on 1D stellar spectra convolutional neural network (1D SSCNN). In 1D SSCNN, we modify the traditional 2D convolutional neural network into 1D network to adapt to the spectral classification. On the basis of using convolution algorithm, the spectral features are extracted and used for classification. We first use the stellar spectra data to train a 1D SSCNN to obtain a well-trained model, and then we apply the well-trained model to classify the unknown spectra. To evaluate the performance of the proposed algorithms, we apply 1D SSCNN to classify three spectral types: F-type spectra, G-type spectra, and K-type spectra and 10 subclasses of K-type spectra: A0-type, A5-type, F0-type, F5-type, G0-type, G5-type, K0-type, K5-type, M0-type, and M5-type spectra from Sloan Digital Sky Survey (SDSS). Our 1D SSCNN algorithm obtain higher classification accuracy compared with support vector machine (SVM), random forest (RF), and artificial neural network (ANN). [ABSTRACT FROM AUTHOR]

Abstract: Two new coordination polymers, namely {[Cu2(DCTP)2](H2O)}n (I) (H2DCTP = 4'-(3,5-dicarboxyphenyl)-4,2':6',4''-terpyridine) and {[Zn5(NTB)4(DMF)2](H2NMe2)2(DMF)3}n (II) (H3NTB = 4,4′,4″-nitrilotribenzoic acid, DMF = N,N-dimethylformamide), have been successfully constructed under solvothermal conditions. The structures of two complexes have been successfully determined by single crystal X-ray diffraction (CIF files CCDC nos. 1852377 (I) and 1852378 (II)). In addition, in vitro antitumor activity of compounds I and II on four human kidney cancer cells (GRC-1, A-498, ACHN and 786-P) was further determined and the results show that the two compounds showed promising activity. [ABSTRACT FROM AUTHOR]

Primary combustion products of boron-based propellants are incomplete combustion products that are emitted from the gas generator of a solid ducted rocket. Studying the composition of primary combustion products provides valuable information about the primary combustion process and also helps to better understand the secondary combustion process. The particle size of the primary combustion products is analyzed by a laser particle size analyzer. The qualitative analysis of the sample composition is performed by using x-ray diffraction, x-ray photoelectron spectroscopy, and thermogravimetry-differential scanning calorimetry experiments. Based on these results, an integrated quantitative analysis of the sample composition is conducted. The quantitative analysis methods include tube furnace heating, ion chromatography, infrared spectroscopy, and inductively coupled plasma chromatography. In addition, scanning electron microscopy and energy dispersive spectrometry are also used to analyze the micro-morphology and distribution of different components in the sample. The primary combustion products mainly contain B, C, BC, HBO, BO, BN, Mg, MgCl, and NHCl. BC (22-24%), HBO (20%), and B (16.8%) are the three major components, while BC, B, and C (9.8-11.8%) are the three combustible components present in the highest amounts. The oxidant NHClO is completely consumed during the primary combustion, while the metal additive Mg does not show much reactivity. The micro-morphology and distribution of BC, HBO (or BO), B, Mg, and C in the sample are investigated. Some components in the primary combustion products are found to be agglomerated, while some components are dispersed. Large particles in the sample mainly include B and Mg, while BC, HBO (or BO), and C particles are small. In general, the combustion completeness of the primary combustion products is rather low. Therefore, better understanding and controlling of the secondary combustion process is very important to improve the performance of B-based propellants. [ABSTRACT FROM AUTHOR]

We investigate the strain relaxation and surface morphology of epitaxial SrTiO3 (STO) films grown on (001)O and (110)O planes of orthorhombic NdGaO3 (NGO), and (001) plane of cubic (LaAlO3)0.3(Sr2AlTaO6)0.7 (LSAT) substrates. Although the average lattice mismatches are similar, strikingly regular crosshatched surface patterns can be found on STO/NGO(001)O[(110)O] films, contrary to the uniform surface of STO/LSAT(001). Based on the orientation and thickness dependent patterns and high-resolution x-ray diffractions, we ascribe the crosshatch morphology to the anisotropic strain relaxation with possibly the 60° misfit dislocation formation and lateral surface step flowin STO/NGOfilms, while an isotropic strain relaxation in STO/LSAT. Further, we show that the crosshatched STO/NGO(110)O surface could be utilized as a template to modify the magnetotransport properties of epitaxial La0.6Ca0.4MnO3 films. This study highlights the crucial role of symmetry mismatch in determining the surface morphology of the perovskite oxide films, in addition to their epitaxial strain states, and offers a different route for designing and fabricating functional perovskite-oxide devices. [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]

Abstract: High-energy synchrotron X-ray diffraction technique was used to in-situ characterize microstructure, lattice strain, and phase transition behavior of a Ni47Ti44Nb9 shape memory alloy. Phase transformation kinetics and deformation mechanisms were studied under a uniaxial tension at three testing temperatures, i.e., −70°C, 25°C, and 150°C. At a testing temperature of −70°C, a complicated phase transformation with four stages of micromechanical deformation was identified which is associated with changes of martensite substructures. At room temperature of 25°C, there was no stress-induced selection process of variants of B19′ phases observed. Whereas at a testing temperature of 150°C, there was no any phase transformation observed. It is verified that β-Nb phase, an effective stabilizer for the austenite, delays the process of martensitic transformation and relaxes the strain energy without strengthening the matrix. This new finding is important to understand the relationship between the micromechanical deformation behavior and phase transformations in the Ni47Ti44Nb9 SMA. [Copyright &y& Elsevier]

A composite double zinc phosphate conversion coating was obtained via forming a hopeite crystal layer on an amorphous phosphate layer on the AZ91D magnesium alloy. The surface morphology, structure and phase composition of the composite coating were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). As a comparison, the single zinc phosphate coating and the bare substrate were also discussed. The phosphate crystal clusters can form on the amorphous layer densely and fine. According to the open circuit potential (OCP) and potentiodynamic polarisation curve tests, the composite phosphate conversion coating on the AZ91D magnesium alloy yielded the best protective effect compared with the single amorphous layer and crystal layer. [ABSTRACT FROM AUTHOR]

The Advanced Light Source (ALS) is a 1.9-GeV, third-generation synchrotron optimized for the production of VUV and soft X-rays from undulators. There is also a hard X-ray program at the ALS, which is based around three 6-T superconducting bending magnets [1] that shift the critical energy from 3 keV to 12 keV. The extreme conditions beamline at the ALS is situated on Beamline 12.2.2, which benefits from radiation produced by one of these superbend sources. The beamline is designed for X-ray diffraction, X-ray spectroscopy, and X-ray imaging of samples held in diamond-anvil high-pressure cells (DACs). In a DAC, samples are on the order of 10 to 50 μm in diameter and 10 to 30 μm thick and are contained in a metal gasket of typical inner diameters of 100 to 150 μm. For high-quality diffraction patterns with little or no contamination from diffraction from the gasket, the X-ray beam size needs to be on the order of 10 μm × 10 μm. [ABSTRACT FROM AUTHOR]

We present in situ measurements of the unit-cell volume of a natural terrestrial ilmenite (Jagersfontein mine, South Africa) and a synthetic reduced ilmenite (FeTiO3) at simultaneous high pressure and high temperature up to 16 GPa and 1273 K. Unit-cell volumes were determined using energy-dispersive synchrotron X-ray diffraction in a multi-anvil press. Mössbauer analyses show that the synthetic sample contained insignificant amounts of Fe3+ both before and after the experiment. Results were fit to Birch-Murnaghan thermal equations of state, which reproduce the experimental data to within 0.5 and 0.7 GPa for the synthetic and natural samples, respectively. At ambient conditions, the unit-cell volume of the natural sample [V0 = 314.75 ± 0.23 (1σ) ų] is significantly smaller than that of the synthetic sample [V0 = 319.12 ± 0.26 ų]. The difference can be attributed to the presence of impurities and Fe3+ in the natural sample. The 1 bar isothermal bulk moduli KT0 for the reduced ilmenite is slightly larger than for the natural ilmenite (181 ± 7 and 165 ± 6 GPa, respectively), with pressure derivatives K'0 = 3 ± 1. Our results, combined with literature data, suggest that the unit-cell volume of reduced ilmenite is significantly larger than that of oxidized ilmenite, whereas their thermoelastic parameters are similar. Our data provide more appropriate input parameters for thermo-chemical models of lunar interior evolution, in which reduced ilmenite plays a critical role. [ABSTRACT FROM AUTHOR]