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Diagenetic effect during burial on the hydroxyapatite in enamel and dentin from fossil human and animal teeth was examined, using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). For the enamel and dentin of all fossil teeth, XRD patterns exhibit bulge line and overlap between major reflections of hydroxyapatite, and the crystallinity of hydroxyapatite is low. For each infrared spectrum, H2O and OH(-) have distinct peaks of absorbance, and PO4(3-) and CO3(2-) ions have intensive infrared vibration modes at the fundamental wave numbers. The component of hydroxyapatite of all fossil teeth is similar to the modern biological hydroxyapatite. Furthermore, the index (PCI) which reflects the hydroxyapatite crystallinity of each sample ranges from 2.4 to 4.0 while the index (BPI) reflecting the amount of type B carbonate to phosphate indicates that the values of CO3(2-) content in hydroxyapatite are rather high, accordingly the crystallinity of all fossil hydroxyapatites are poor. It could be concluded that little alteration of hydroxyapatites from fossil human and animal teeth occurred in the process of diagenesis in Jinsha Relict, Chengdu, China.

Different electronic structure on 4 f shell endows rare earth with variable of catalytic activity. In order to explore the catalytic effect of rare earth on solid oxide fuel cell (SOFC) electrode, we prepare electrolyte-supported (Sr 1.8 Ln 0.2)FeMoO 6 /SDC/LSGM/SBCO single cell with Ln = Sr, La, Sm and Eu, and investigate their electrochemical performance based on X-ray diffraction (XRD), DC four-point probe, I-V and electrochemical impedance spectra. XRD results show that (Sr 1.8 Ln 0.2)FeMoO 6 are of single phase and belong to I4/m space group. Owing to the increased density of states, electronic conductivity of (Sr 1.8 La 0.2)FeMoO 6 (SLFM), (Sr 1.8 Sm 0.2)FeMoO 6 (SSFM) and (Sr 1.8 Eu 0.2)FeMoO 6 (SEFM) increases significantly, where SEFM exhibits the highest value in the measuring range. The higher conductivity and the smaller activation energy favor the power output of the investigated cell. The maximum power density of Sr 2 FeMoO 6 (SFMO)-based cell is 772 mW·cm−2 at 850 ℃, that of SLFM- and SSFM-based cell increases to 890.8 mW·cm−2 and 861.6 mW·cm−2, while SEFM-based cell exhibits the highest value of 964.6 mW·cm−2. Electrochemical Impedance Spectroscopy (EIS) finds that SEFM-based cell possesses the smallest electrode resistance, charge transfer resistance, the fastest surface exchange and oxygen diffusion process, which favors its highest power output. These results demonstrate that the synergistic reaction in catalytic activity between rare earth atoms and SFMO lattice is different to a large degree, and our innovative discovery is the good catalytic activity of SEFM anode, which is conducive to comprehensively understanding the catalytic properties of rare earth for SOFC electrodes. • The synergy in catalytic activity between rare earth and Sr 2 FeMoO 6 is different to a large degree. • (Sr 1.8 Eu 0.2)FeMoO 6 exhibits the highest conductivity. • (Sr 1.8 Eu 0.2)FeMoO 6 -based cell depicts the best electrochemical performance. [ABSTRACT FROM AUTHOR]

Treatment of 5,5′-di(trifluoromethyl)-3,3′-bipyrazole (BipzH2) with cis-[RuCl2(Bipy)2]·2H2O (Bipy = 2,2′-bipyridine) or cis-[RuCl2(Dmbipy)2]·2H2O (Dmbpy = 4,4′-dimethyl-2,2′-bipyridine) afforded two charge-neutral ruthenium(II) complexes [Ru(Bipz)(Bipy)2] (I) and [Ru(Bipz)(Dmbipy)2] (II), respectively. Reactions of 3-trifluoromethyl-5-(2-pyridyl)pyrazole (PypzH) and cis-[RuCl2(Bipy)2]·2H2O or cis-[RuCl2(Dmbipy)2]·2H2O in the presence of NH4PF6 produced two cationic ruthenium(II) complexes [Ru(Pypz)(Bipy)2](PF6) (III) and [Ru(Pypz)(Dmbipy)2](PF6) (IV), respectively. Four complexes were spectroscopically characterized by FTIR, UV-Vis and luminescence. The structures of I·H2O, III·H2O and IV have been also determined by single-crystal X-ray diffraction (CIF files CCDC nos. 1935282–1935284, respectively). [ABSTRACT FROM AUTHOR]

A new supramolecular complex [Cd(dcbpy)(im)2(H2O)2] · 3H2O (H2dcbpy = 4,4'-dicarboxy-2,2'-bipyridine, im = imidazole) has been prepared under hydrothermal conditions. Its crystal structure is determined with single crystal X-ray diffraction. Cd2+ atom is six-coordinated by one dcbpy ligand, two imidazole and two water molecules. Each [Cd(dcbpy)(im)2(H2O)2] unit is connected to neighboring units through intermolecular O–H···O hydrogen bonds to form a three-dimensional supramolecular network structure. A topology method has been used to simplify the network. The stability and luminescent properties of the complex obtained have been investigated. [ABSTRACT FROM AUTHOR]

Hexagonal Ba(Ti1-xFex)O3-δ (x = 1/6, 1/3) ceramics treated with post annealing are specifically synthesized to explore the origin mechanism of the unusual ferromagnetism in the doped system. X-ray diffraction refinements and transmission electron microscope experiments reveal that their structures are incommensurately modulated owing to simultaneous oxygen vacancies at both O1 and O2 sites. Consequently, coexisting weak ferrielectricity and weak ferromagnetism are presented at room temperature. Analysis on their leakage current plot reveals that their conduction follows trap-filled limit model. In combination with the magnetism studies on 5 mol% Fe-doped crystals [Phys. Rev. B 83, 144407 (2011)], the reduction of ferromagnetism with an increase of conductivity suggests that dynamic exchanges of trapped electrons among the bound magnetic polarons attribute to the intrinsic ferromagnetism. [ABSTRACT FROM AUTHOR]

Tm3+ and Ho3+ codoped transparent glass ceramic (GC) containing CaF2 nanocrystals were fabricated by melt-quenching and subsequent thermal treatment. X-ray diffraction and transmission electron microscopy analysis confirmed the precipitation of CaF2 nanocrystals among the glass matrix. Energy-dispersive x-ray spectroscopy results evidenced the incorporation of Tm3+ and Ho3+ into the CaF2 nanocrystals. Judd-Ofelt parameters were calculated based on the absorption spectra, the smaller Ω2 and larger Ω6 imply that Tm3+ and Ho3+ ions has entered into a symmetrical ionic crystal field. 2.02 μm emission spectral of the GC samples were recorded at room temperature with an excitation of 808 nm laser diode. The enhancement of the emission at 2.02 μm in the GC samples could be attributed to more efficient cross relaxation process of Tm3+ : 3H4+Tm3+ : 3H6 →2Tm3+ : 3H4, and energy transfer from Tm3+ to Ho3+ benefited from the incorporation of rare earth ions into CaF2 nanocrystals. [ABSTRACT FROM AUTHOR]

In this study, the pyroelectric coefficient and the figure of merit (FOM) of the ferroelectric (FE) PbZr0.3Ti0.7O3 (PZT 30/70) thin films were found to be greatly enhanced by introducing a thin antiferroelectric (AF) PbZr0.95Ti0.05O3 (PZT 95/05) layer underneath the FE film and thus creating a bilayer structure on platinized silicon substrates. The film properties were investigated as a function of the FE layer thickness when the thickness of AF layer remained unchanged. The highest pyroelectric coefficient of 1 μm thick PZT 30/70 film was 3.18×10-4 cm-2 K-1. However, the highest pyroelectric coefficient for 1 μm thick bilayer film was 3.5×10-4 or 2.5×10-4 cm-2 K-1 for only 280 nm thick bilayer film. The enhancement of pyroelectric coefficient suggests switching of AF into FE phase during poling and following stabilization of FE phase at room temperature. The reduction in dielectric constant in bilayer films after poling, compared to pure PZT 30/70, showed a FOM of 2.94×10-5 Pa-0.5, which is the double of the FOM for pure PZT 30/70 films of similar thickness (1.45×10-5 Pa-0.5). [ABSTRACT FROM AUTHOR]

Magnetic properties and magnetocaloric effect of the ferrimagnetic compounds Gd4Co3 and (Gd0.9Dy0.1)4Co3 have been studied. In Gd4Co3, two successive magnetic-entropy changes occur due to a spin-reorientation transition at TSR=163 K and a ferrimagnetic-magnetic ordering transition at TC=220 K. For a field change from 0 to 5 T, -ΔSMmax at TC is 5.74 J/kg K, the full width at half maximum (δTFWHM) of the -ΔSM versus T curve has a high value of 131 K, and the refrigerant capacity is as high as 575 J/kg. TC can easily be tuned by Dy substitution for Gd and the magnetic-entropy change is increased simultaneously. -ΔSMmax of (Gd0.9Dy0.1)4Co3 at TC=145 K for the same field change has increased to 8.47 J/kg K. Our studies suggest that the successive magnetic transitions could enlarge the temperature interval, which makes this type of material meaningful for magnetic refrigeration in wider temperature regions than conventional materials. [ABSTRACT FROM AUTHOR]

We demonstrate a facile approach for the synthesis of Zn2SiO4:Tb3+,Yb3+ transparent thin films. The thin film phosphor was characterized by various methods including x-ray diffraction, atom force microscope, and photoluminescence studies. Upon excitation with a UV-blue photon in the range of 350–485 nm, an intense near-infrared (NIR) emission at around 900–1100 nm has been obtained, which is assigned to the electronic transition 2F7/2→2F5/2 of Yb3+ upon exploring the cooperative down conversion mechanism from Tb3+ to Yb3+. The dependence of Yb3+ doping concentration on the visible- and NIR-emissions, decay lifetime, and quantum efficiencies of the thin-films has been investigated. The optimal internal NIR quantum efficiency could be as high as 154.1%. [ABSTRACT FROM AUTHOR]

Bulk-quantity single crystalline Ge dioxide nanowires (GeONWs) have been prepared via a facile and simple hydrothermal deposition process using GeO2 powder. Transmission electron microscopy (TEM) observations show that the GeONWs have a high purity, diameter ranging from 30 to 300 nm, and length of longer than 10 μm. X-ray diffraction, Fourier transform infrared, high-resolution TEM, and selected area electron diffraction pattern of the GeONWs indicate that the nanowires are single crystalline GeO2 with hexagonal structure. Room temperature photoluminescence measurement shows that the synthesized GeONWs have intense violet light emission and blue light emission at 370 and 476 nm, respectively. It is proposed that the GeONWs may follow the vapor-solid growth mechanism. [ABSTRACT FROM AUTHOR]

In this research, CoxSi1−x granular films with Co volume fraction (x) varying from 0.36 to 1 were prepared by using a magnetron co-sputtering method. The influence of x on the temperature-dependent longitudinal resistivity (ρxx) and anomalous Hall effect (AHE) in CoxSi1−x granular films were systematically studied. The dependence of ρxx on measuring temperature could be explained by the superposition of fluctuation-induced tunneling (FIT) process and temperature-dependent scattering. Interestingly, the contribution from scattering and FIT can be distinguished. The saturated Hall resistivity (ρxyA) increased monotonically with decreasing x. In addition, the ρxyA amplified nearly 26-fold as x decreased from 1 to 0.4. For the pure Co film (x = 1), the intrinsic and side jump mechanisms dominated the Hall transport. However, the deviation of classical scaling relation was observed in other samples, which was mainly ascribed to the influence of interfacial scattering. [ABSTRACT FROM AUTHOR]

A mononuclear coordination complex, quinidinum-zinc(II)-trichloride (I), and a multi-component ionic complex, quinidinum iron(III) tetrachloride hydrogen chloride hydrate (II), have been synthesized and characterized by elemental analyses, IR spectra, and single crystal X-ray diffraction (CIF files nos. 1497628 (I) and 1497629 (II)). The weak hydrogen-bonding interactions exist in both complexes I and II. Both complexes crystallize in the chiral space groups with the absolute configuration. Complex I crystallizes in the orthorhombic space group P212121 with a = 7.6651(6), b = 11.4923(9), c = 24.653(2) Å, and Z = 4. Complex II crystallizes in the monoclinic space group P21 with a = 6.6425(15), b = 18.660(4), c = 10.958(3) Å, β = 104.973(3), and Z = 2. [ABSTRACT FROM AUTHOR]

Two polymeric frameworks, [Zn(Dpb)(Oba)] ( Ι) and [Cd(Dpb)(2,6-Pda)HO] · nHO ( II) (Dpb = 1,4-bis(pyridin-3-ylmethoxy)benzene, HOba = 4,4'-oxybis(benzoic acid), 2,6-HPda = 2,6-pyridyl-dicarboxylate), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction method (CIF files CCDC 1488269 ( Ι), 1488270 ( II)). Complex Ι is a 2D layer structure, which is constructed from 1D double chain. Complex II is a 1D chain. The luminescent properties of Ι, II have been investigated with fluorescent spectra in the solid state, I and II displayed a strong fluorescent emission at room temperature. [ABSTRACT FROM AUTHOR]

In the present work, the effects of phase constitution on the magnetic and mechanical properties of FeCoNi(CuAl) x ( x = 0–1.2, in molar ratios) high-entropy alloys (HEAs) have been investigated by using vibrating sample magnetometer (VSM), mechanical tester combined with X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and differential scanning calorimeter (DSC). From the experimental results, the crystallographic structures of FeCoNi(CuAl) x HEAs transform from single face-centered cubic (FCC) phase for 0 ≤ x ≤ 0.6 to body-centered cubic (BCC) phase combined with minor FCC phase for 0.9 ≤ x ≤ 1.2, whereas FCC plus BCC duplex phases are found in the range of 0.7 ≤ x < 0.9. TEM images of FeCoNi(CuAl) 0.8 alloy show large numbers of FCC Cu-rich nano-precipitates disperse in the BCC matrix. Furthermore, it is found that the saturation magnetization ( M s ) of HEAs with FCC plus BCC duplex structures abnormally increase with the additions of Cu and Al in contrast to single-phase HEAs, showing a linear decrease in M s . On the other hand, annealing at 573–673 K can lead to a remarkable increase in M s for FCC plus BCC duplex-phase HEAs other than the single-phase HEAs with almost unchanged M s . Specifically, annealing under a given condition can lead to the occurrence of phase transition from FCC to BCC phase for FeCoNi(CuAl) 0.8 HEAs, resulting in a substantial increase in the M s from 78.9 Am 2 /kg to 93.1 Am 2 /kg and yield strength from 536.7 MPa to 1141.1 MPa. The outreach of the present work might provide a promising way to develop HEAs with a combination of superior magnetic and mechanical properties. [ABSTRACT FROM AUTHOR]

To better understand β grain morphology control during the laser additive manufacturing of titanium alloys, a damage tolerance α+β titanium alloy, Ti6Al2Sn2Zr3Mo1.5Cr2Nb alloy, was built by laser solid forming (LSF) with different process strategies. The corresponding microstructure and macrotexture were investigated using optical microscopy and X-ray diffraction. Near equiaxed grains, columnar grains (both vertical and inclined) and mixed grain morphology were obtained by suitable control of the processing parameters. The surviving captured powders in the molten pool could act as a substrate core for equiaxed dendritic growth. A lower laser energy density and smaller remelt depth are critical for the formation of equiaxed grains. As expected, near equiaxed grains are more isotropic in crystallographic texture. Both vertical and inclined columnar grains, which exhibit strong but imperfect <100> fiber texture, are easy to obtain using higher laser energy density. The formation of the inclined columnar grains is attributed to the main heat flow direction occurring along the deposition direction and inclining towards the laser scanning direction. The imperfect fiber texture characterization was obtained due to the hereditary crystallographic orientation of the wrought substrate, as certain preferred (100) poles of the substrate present a minimal angle with the temperature gradient at the bottom of the molten pool. Based on the mechanisms of grain morphology formation and the relationship with the processing parameters, the grain morphology and texture in LSFed titanium alloy can be controlled. [ABSTRACT FROM AUTHOR]

Lead-free 0.94NaBiTiO-0.06BaTiO (NBT-0.06BT) ceramics (0.0 ≤ x ≤ 0.03) were synthesized by a conventional solid-state reaction process. X-ray diffraction shows that the compositions are at the morphotropic phase boundary where rhombohedral and tetragonal phase coexist. Grain size slightly changes with the increase of Ba content and reaches the minimum at x = 0.02. The depolarization temperature ( T ) decreases with the extra Ba content but the lowest T was obtained at x = 0.01-0.02. The pyroelectric coefficient ( p) was measured as a function of Ba content, and increased from 2.90 × 10 to 3.54 × 10 C m °C, and from 55.3 × 10 to 740.7 × 10 C m °C for x = 0.00 and 0.02 at RT, and depolarization temperature ( T ) respectively. The pyroelectric coefficient ( p) shows a large increase with rising the temperature and reaches the maximum value at the depolarization temperature ( T ). The figures of merits of F , F and F have all been improved with the addition of extra barium. These improved pyroelectric properties indicate that NBT-0.06BT is a promising material for pyroelectric applications or a wide range of temperature. [ABSTRACT FROM AUTHOR]

Nonstoichiometric Sr 2 FeMoO 6−δ (δ = 0.132 and 0.296) double perovskite compounds have been synthesized by solid-state reaction. Effect of oxygen vacancy on its structural, magnetic and transport properties has been investigated by X-ray diffraction, magnetic and electronic transport measurements. Despite of different oxygen vacancy, both two compounds are of single phase and belong to the same space group, I4/m. Structural refinement shows that oxygen vacancy lowers the degree of ordering on B site and increases the lattice constant. Further structural analysis finds that owing to the oxygen vacancy, Fe atom is compressed, while the Mo atom changes from being compressed to being elongated. As predicted by the theoretical calculation, besides anti-site defects, oxygen vacancy is another important source for the lower Curie temperature of nonstoichiometric Sr 2 FeMoO 6−δ . Meanwhile, the hopping integration of electron between Fe–O–Mo–O–Fe is reduced by oxygen vacancy, thus the resistivity and the semiconducting-metallic transition temperature of Sr 2 FeMoO 6−δ are enhanced. However, the saturation magnetization (M S ) of Sr 2 FeMoO 6−δ at 5 K can be repeated well based on the ferrimagnetization model, suggesting that the anti-site defect is responsible for the reduction of M S , which is different from the literature results. [ABSTRACT FROM AUTHOR]

Hollow microspheres are usually used as a lightweight filler in syntactic foams. In this work, Al2O3 sols were selected and prepared under optimised conditions. A layer of Al2O3 film was prepared on hollow glass microspheres by the sol-gel process. The phase and element evolution of Al2O3 gel powders during exsiccation and heat treatment was investigated by infrared spectroscopy (IR) and X-ray diffraction (XRD). The 1-3 layers of coatings were prepared using a dipping method and characterised by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The results show that clear stable sols can be obtained at 80-90°C with n(H2O): n(Al3+) greater than 150∶1 and pH 2·7-3·5. After exsiccation, AlOOH, the precursor of Al2O3 sols, can be totally eliminated and turned into Al2O3. Coatings with double layers have the best effect for covering the hollow microspheres. [ABSTRACT FROM AUTHOR]

An Fe-Al multilayer alloy plate was designed and fabricated using hot-dipping aluminium plating at 800°C for 150 s and the diffusion alloying process at 900°C. A multilayer structure of the Fe-Al intermetallic alloy, including Fe2Al5, FeAl2, FeAl and α-Fe (Al), was formed on the surface of a pure iron substrate. After annealing, Fe2Al5/substrate/Fe2Al5 diffusion couples became Fe2Al5/FeAl2/FeAl/α-Fe(Al)/substrate/α-Fe(Al)/FeAl/FeAl2/Fe2Al5. The Al content decreased from surface to centre and showed a gradient distribution. The geomagnetic shielding factor of the Fe-Al multilayer alloy plate was 23·6, about seven times as high as pure iron. The excellent shielding effectiveness was ascribed to the structure of soft magnetic alloy layer/substrate/soft magnetic alloy layer. [ABSTRACT FROM AUTHOR]

To prevent carbon/carbon (C/C) composites from oxidation, a phosphate coating was prepared on the composites by a simple and low cost slurry technique. The effect of B2O3/SiO2 mass ratio on the microstructure and oxidation resistant property of phosphate coating was studied. The coating characterised by scanning electron microscopy and X-ray diffraction is mainly composed of SiO2, BPO4 and Al(PO3)3. Oxidation tests show that, as the mass ratio of B2O3 and SiO2 is 1∶1, the coating possessed excellent oxidation resistant ability. After oxidation in air at 700°C for 30 h and thermal cycling between 900°C and room temperature for 50 times, the weight losses of the coated samples were only 4·3 and 0·35% respectively. The weight loss of the coated C/C composites was considered to arise from the formation of bubble holes and microcracks in the phosphate coating. [ABSTRACT FROM AUTHOR]

Thermal barrier coatings of nanostructured and microstructured yttria stabilized zirconia (YSZ) were deposited on GH4049 substrate by air plasma spray, respectively. Hot corrosion behaviors of both coatings were evaluated in comparative aspects. Results revealed that the nanostructured YSZ displayed higher resistance to the hot corrosion attack by Na2SO4 and V2O5. It was also shown, through X-ray diffraction quantitative phase analysis, that the nanostructured YSZ had good resistance to the tetragonal-monoclinic phase transformation during the hot corrosion process. [ABSTRACT FROM AUTHOR]

Two new Schiff base zinc(II) complexes, [ZnBrL] ( I) and [ZnClL] ( II), where L is 4-bromo-2-[(3-diethylaminopropylimino)methyl]phenol, were synthesized and characterized by physico-chemical methods and single crystal X-ray diffraction. The crystal of I is monoclinic: space group P2/ n a = 7.250 (2), b = 16.136 (3), c = 15.802 (3) Å, β = 90.027 (3)°, V = 1848.6 (7) Å, Z = 4. The crystal of II is monoclinic: space group P2/ n, a = 7.177 (3), b = 15.970 (4), c = 15.689 (3), β = 91.674 (3)°, V = 1797.5 (9) Å, Z = 4. The Zn atom in each complex is four-coordinated by one phenolate O and one imine N atoms of the Schiff base ligand and two halide atoms, forming a tetrahedral coordination. The urease inhibitory activities of the complexes were evaluated. [ABSTRACT FROM AUTHOR]

Poly(vinylidene fluoride) (PVDF)-graphite nanosheet (GNS) nanocomposites with different contents of GNSs were prepared by the solution-casting method. The GNSs were produced by the ultrasonic exfoliation of graphite. The effects of GNSs on the crystalline structure, degree of the crystallization, conductivity, and phase-transformation mechanism of PVDF were investigated. Atomic force microscopy data showed that the GNSs had a flake-shaped nanostructure. Fourier transform infrared spectroscopy and X-ray diffraction results revealed that a β phase formed with the addition of GNSs, and the phase-transformation mechanism from the α phase to the β phase of PVDF was confirmed. Differential scanning calorimetry results indicated that addition of GNSs led to an increased melting temperature and increased degree of crystallization; this implied that the GNSs acted as nucleating agents. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 [ABSTRACT FROM AUTHOR]

Single-phased Y2-xSi3O3N4:xCe3+ (0 < x ≤ 0.4) phosphors were prepared by solid-state reaction method in flowing hydrogen and nitrogen mixture gas. The X-ray diffraction analysis indicated that Ce3+ ions had been incorporated into the host lattice of Y2Si3O3N4, and the optimized doping concentration was 3 mol%. Strong absorption peaking at about 397 nm was observed on the excitation spectra for the Ce3+-doped phosphors, which matched well with the current near-ultraviolet (NUV) InGaN/GaN light emitting diodes (LEDs). The Y2-xCexSi3O3N4 samples showed a broad emission band with peak wavelength ranging from 465 to 500 nm, which was attributed to the 5d-4f transition of Ce3+. Energy transfer between Ce3+ ions was discussed and evidenced in detail, which resulted in redshift of the emission and concentration quenching. To understand the thermal quenching behavior, the temperature-dependent luminescence of Y1.94Ce0.06Si3O3N4 was investigated. Bluish-green LEDs was fabricated by integrating a near-ultraviolet (NUV) chip with Y1.94Si3O3N4:0.06Ce3+ phosphor as a single package. [ABSTRACT FROM AUTHOR]

Abstract: TiO2–M–TiO2 (M=W, Co and Ag) multilayer films have been deposited on glass substrates using reactive magnetron sputtering, then annealed in air for 2h at 500°C. The structure, surface morphology and optical properties of the films have been studied using X-ray diffraction, Raman spectroscopy, atomic force microscopy and UV–vis spectroscopy. The TiO2–W–TiO2 and TiO2–Co–TiO2 films showed crystalline phases, whereas the TiO2–Ag–TiO2 films remained in the amorphous state. The crystallization temperature for the TiO2–M–TiO2 films decreased significantly compared with pure TiO2 film deposited on quartz. Detailed analysis of the Raman spectra suggested that the crystallization of TiO2–M–TiO2 films was associated with the large structural deformation imposed by the oxidation of intermediate metal layers. Moreover, the optical band gap of the films narrowed due to the appearance of impurity levels as the metal ions migrated into the TiO2 matrix. These results indicate that the insertion of intermediate metal layers provides a feasible access to improve the structural and optical properties of anatase TiO2 films, leading to promising applications in the field of photocatalysis. [Copyright &y& Elsevier]

The spinel FeV2O2 is known to exhibit peculiar physical properties, which is generally ascribed to the unusual presence of two cations showing a pronounced interplay between spin, orbital, and lattice degrees of freedom (Fe2+ and V2+ on the tetrahedral and octahedral sites, respectively). The present work reports on an experimental reinvestigation of this material based on a broad combination of techniques, including x-ray diffraction, energy dispersive, and Mössbauer spectroscopies, as well as magnetization, heat capacity, dielectric, and polarization measurements. Special attention was first paid to establish the exact cationic composition of the investigated samples, which was found to be Fe1.18 V1.82O4. All the physical properties were found to point out a complex ordering process with a structural transition at Ts = 138 K, followed by two successive magnetostructural transitions at TN1 = 111 K and TN2 = 56 K. This latter transition marked the appearance of electric polarization, and magnetization data were analyzed in detail to discuss the nature of the magnetic state at T < TN2- An overall interpretation of the sequence of transitions was proposed, taking into account two spin couplings, as well as the Jahn-Teller effects and the mechanism of spin-orbit stabilization. Finally, the origin of ferroelectricity in Fe1.18 V1.82O4 is discussed on the basis of recent models. [ABSTRACT FROM AUTHOR]

Abstract: The Copper-doped cobalt oxide films have been prepared onto titanium support by reactive DC magnetron sputtering. The deposits are characterized by X-ray diffraction (XRD), energy-dispersive spectrometry (EDS), Ultroviolet (UV) and scanning electron microscope (SEM). The electrochemical characteristics of deposits are explored by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The effect of copper content in the Cu–Co oxides on the surface morphology, electrochemical and crystallographic properties has been investigated. The introduction of Cu element makes the Cu–Co oxides deposit fine and further lead to high roughness of deposits, which is helpful for the oxides’ electrochemical performance. Based on the electrochemical determination, the binary oxide electrodes exhibit better catalysis activity than that of CuO and Co3O4 electrodes for oxygen evolution reaction (OER). The increase OER activity has been attributed to the enlarged surface roughness and the new active sites of deposits, according to the results of EIS. [Copyright &y& Elsevier]

Abstract: Electron doped double perovskite compound (Sr2− x Sm x )FeMoO6 (0≤x≤0.25) has been synthesized by solid-state reaction at high temperature. Crystal structure and magnetic properties of the compounds have been investigated by X-ray powder diffraction (XRD) and magnetic measurements. XRD revealed that all the compounds were of single phase and belonged to a I4/m lattice. The degree of cationic ordering on the B site was decreased pronouncedly by the electron doping. Different from the results of La- and Nd-doped Sr2FeMoO6, Curie temperature (T C) of (Sr2− x Sm x )FeMoO6 decreased first with the doping and then increased beyond x=0.15, indicating that steric effect was enhanced as the radius of rare-earth ions decreased. Saturation magnetization (M S) of the compounds decreased with the doping level and anti-site (AS) concentration. Sm moment showed a considerable contribution to M S at low temperature, leading to an abrupt drop of M S between x=0.1 and 0.15. [Copyright &y& Elsevier]

Abstract: The magnetic nanopowders can be potentially applied in wide range of fields such as magnetic storage, magnetic fluid, medical diagnosis, conducting paints, rechargeable batteries, optoelectronics, magnetic recording media, drug delivery system and catalysis. They have attracted interest in the past decade and have also been studied extensively because of their size- and shape-dependent physical-chemical and magnetic properties for applications in various useful technologies. In this work, we present our experimental results on the preparation of nanosized Ni nanoparticles with different shapes by using a wet chemical solution route. Ni nanoparticles were prepared by reducing a Ni-complex formed between nickel-acetate and hydrazine solution under basic condition. Then through the control of reaction temperature and ageing time, nanosized Ni particles with different morphologies could be formed. The morphology and sizes of synthesized nanostructures were studied by scanning electron microscopy (SEM). Structural properties of nanoparticles were examined by X-ray diffraction. We also report the core-shell structures of micro-composites of silica-nickel (SiO2/Ni). The composite core-shell structures were formed by the control of the surface charges of particles in aqueous solutions. A specific composite (SiO2/Ni) can be produced by controlling the surface charge, the pH and the molar ratio of the components. Core-shell structures are stable at room temperature. [Copyright &y& Elsevier]

Abstract: Thermoelectric materials Mg2−x Ca x Si (x =0, 0.01, 0.03, 0.05, 0.07, 0.1) compounds have been prepared by vacuum melting followed by hot-pressing. Effects of the substitution of Ca for Mg on phase structures and the thermoelectric properties of the hot-pressed compounds were investigated. It was found that the alloying of Ca in Mg2Si based compounds increases the electrical conductivity and decreases the Seebeck coefficient of the compounds, due to the electronegativity difference between Ca and Mg. The dimensionless figures of merit of Mg2Si and Mg1.99Ca0.01Si reach, respectively, 0.41 and 0.34 at 660K. [Copyright &y& Elsevier]

The effect of compensator on optical properties of Ca2Al2SiO7:Eu3+ is systematically investigated by the X-ray powder diffraction, photo-luminescence (PL) properties and lifetime. It is obviously observed that the PL intensity of Eu3+ under 394 nm excitation increases in the order of Ca1.86Eu0.14Al2SiO7 (CAS), Ca1.72Na0.14Eu0.14Al2SiO7 (CASNa) and Ca1.86Eu0.14Al2.14Si0.86O7 (CASAl), the intensity of Eu3+ are 100%, 134%, 184%, and the lifetime of Eu3+ are 0.75 ms, 1.28 ms and 1.39 ms, respectively. A charge compensation model is proposed to explain the changes in the emission intensity and lifetime of Eu3+ in Ca2Al2SiO7 with different compensation methods. [ABSTRACT FROM AUTHOR]

Removal of arsenic(V) from aqueous solutions was evaluated with the following three different sorption materials: coal-based activated carbon 12 x 40 (activated carbon), iron(II) oxide (FeO)/activated carbon-H, and iron oxide. The apparent characteristics and physical chemistry performances of these adsorbents were investigated by X-ray diffraction, nitrogen adsorption, and scanning electronic microscope. Also, batch experiments for arsenic removal were performed, and the effects of pH value on arsenic(V) removal were studied. The results suggest that the main phases of the iron oxide surface are magnetite, maghemite, hematite, and goethite; fine and uniform iron oxide particles can cover activated carbon surfaces and affect the surface area or pore structures of ]activated carbon; adsorption kinetics obey a pseudo-first-order rate equation; and adsorption capacities of adsorbents are affected by the values of pH. The optimum value of pH for iron oxide lies in a narrow range between 4.0 and 5.5, and arsenic(V) removal by FeO/activated carbon-H is ideal and stable in the pH range 3 to 7, while activated carbon has the lowest adsorption capacity in the entire pH range. Also, the adsorption characteristics of FeO/activated carbon-H composites and virgin activated carbon match well the Langmuir adsorption model, while those of iron oxide fit well the Freundlich adsorption model. [ABSTRACT FROM AUTHOR]

Abstract: Crystal structure, magnetic and electrical-transport properties of the rare-earth-doped compounds (Sr1.85Ln0.15)FeMoO6 (Ln=Sr, La, Ce, Pr, Nd, Sm and Eu) have been investigated by means of X-ray diffraction, magnetic and electric measurements. All the samples are single phase and belong to the I4/m space group. Due to the competing contributions of electron doping and steric effects, the unit-cell volume of the doped compounds changes slightly and does not vary systematically with the ionic radius of the rare-earth ions. The temperature dependence of the magnetization of (Sr1.85Ln0.15)FeMoO6 indicates that the Curie temperature of the doped compounds has increased upon doping, except for the Eu-doped compound. The saturation magnetization of the compounds at 5K cannot be explained simply by considering the ferrimagnetic arrangement of the magnetic sublattices of Fe and Mo because of the magnetic contribution of rare-earth ions. However, the saturation magnetization at 100K of the doped compounds exhibits a linear decrease with the increase of the anti-site defect concentration. Comparison of the saturation magnetization of the compounds at 5 and 100K suggests that at 5K the magnetic moments of Ce, Pr, Nd and Sm align parallel with that of Fe, while the magnetic moment of Eu is anti-parallel with that of Fe. The normalized resistivities of the parent and the La- and Sm-doped compounds exhibit a semiconductor-metal transition, while the Pr-, Nd- and Eu-doped compounds exhibit semiconducting behavior. [Copyright &y& Elsevier]

Abstract: The crystal structure of double perovskite Sr2FeMoO6 synthesized via solid-state reaction at 1280°C under a reduction atmosphere is refined by Rietveld technique based on X-ray powder diffraction (XRD) data in 2θ range of 15–140°. An antisite content (AS), i.e. Fe on the Mo sites (=Mo on the Fe sites), of 12.1(1)% is derived. In reference to the refinement results, a series of X-ray and neutron powder diffraction (NPD) data with different antisite contents, ranging from 0 (completely ordered) to 50% (completely disordered), are generated with a Poisonian noise added and subjected to Rietveld refinements with the same initial values for the refinable parameters. The AS is reproduced satisfactorily from the refinement of XRD data and the combined refinement of XRD and NPD data with a relative deviation smaller than 4%, whereas the relative deviation of AS derived from the refinement of NPD data can be as large as 50%. However, the atomic occupancies and isotropic temperature factors of all the atoms can be reasonably reproduced from the refinement of NPD data and the combined refinement of XRD and NPD data, whereas these data can be reproduced only for cations (Sr, Fe, Mo) from the refinement of XRD data. The present simulation studies shed light on understanding the controversial statements derived from XRD and NPD work regarding the antisite defects in Sr2FeMoO6, which in turn is indispensable for understanding the mechanism of large room temperature low-field magnetoresistance of the compound. [Copyright &y& Elsevier]

Liquefied petroleum gas (LPG) fuel was directly synthesized from syngas over a hybrid catalyst which contained a methanol synthesis catalyst and zeolite. The new hybrid catalyst composed of (Pd–Ca/SiO2) and β-zeolite, showed a high activity and selectivity for LPG production. X-ray diffraction (XRD) characterization of the catalyst was used to analyze the deactivation of (Pd–Ca/SiO2)/β-zeolite. [ABSTRACT FROM AUTHOR]

The (LaBa)Co2O5+δ thin films were grown on (001) SrTiO3 single crystal substrates by using pulsed laser deposition. Microstructure studies from x-ray diffraction and electron microscopy show that the films have good epitaxial quality with a-axis orientation and sharp atomic interface. Transport property and isothermal magnetoresistance measurements have been used to understand the physical properties of the films with anomalous magnetic phenomena and the largest reported magnetoresistance value of 19% at 40 K. [ABSTRACT FROM AUTHOR]

A magnetic mesoporous silicon (MMS) composite with magnetic particles as the core and mesoporous as the shell was prepared. The MMS composite was characterised by means of transmission electron microscopy (TEM), X-ray diffraction (XRD), and nitrogen adsorption. The MMS composite with the pore-size of 2 and 200 nm in diameter had a good application prospect in the magnetic-induction hyperthermia and drug delivery. The composite function of magnetic-induction hyperthermia was measured by a high-frequency-induction heating machine with the frequency 608 kHz and the field amplitude 6.4 kA m− 1.The magnetic mesoporous composite took about 7 min to heat up 45°C with the average heating rate of 2.25°C min− 1.The function of loading doxorubicin (DOX) hydrochloride was measured at 488 nm on a UV–Vis spectrophotometry, and the loading efficiency with 20.1% was achieved for the DOX hydrochloride being possibly loaded into the mesoporous. This result put MMS a way of the synchronised therapy of hyperthermia and magnetic target drug delivery. [ABSTRACT FROM AUTHOR]

Nuclear magnetic resonance (NMR), neutron diffraction (ND), x-ray diffraction, magnetic susceptibility X, and specific-heat measurements on the frustrated A-site spinel CoAl2O4 compound reveal a collinear antiferromagnetic ordering below TN = 9.8(2) K. A high-quality powder sample characterized by x-ray diffraction that indicates a relatively low Co-Al inversion parameter x=0.057(20) in (Co1-xAlx)[Al2-xCox]O4, shows a broad maximum around 15 K in X(T) and a sharp peak at TN in heat capacity Cp. The average-ordered magnetic moment of Co2+ (S=3/2) ions at the A site is estimated to be 2.4(1) μB from NMR and 1.9(5) μB from ND which are smaller than the expected value of 3 μB for S=3/2 and g = 2. Antiferromagnetic spin fluctuations and correlations in the paramagnetic state are revealed from the X, NMR, and ND measurements, which are due to spin frustration and site inversion effects in the system. The ND data also show short-range dynamic magnetic ordering that persists to a temperature that is almost twice TN. [ABSTRACT FROM AUTHOR]

Abstract: Nanocrystalline La2/3Ca1/3MnO3+ δ powders were successfully synthesized by a new citrate pyrolysis process modified by methylcellulose additive. The particle size can be controlled effectively by adjusting the treatment temperature. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to study the microstructure and morphology of these nanomaterials. The effects of pyrolysis conditions on the formation of La2/3Ca1/3MnO3+ δ nanocrystalline have been investigated and discussed in brief. [Copyright &y& Elsevier]

Abstract: The structural and magnetic properties of Nd1− x Tb x Fe10.5Mo1.5 (, 0.2, 0.4, 0.6, 0.8, 1.0) compounds have been investigated by means of X-ray diffraction and magnetic measurements. All the investigated compounds crystallize in the tetragonal ThMn12-type structure with I4/mmm space group. The lattice parameters a, c and the unit-cell volume V decrease with increasing x. The Curie temperatures T C are almost independent x. There exists a unique spin-reorientation transition for the end compositions of Nd1− x Tb x Fe10.5Mo1.5 compounds with and , while two spin-reorientation transitions are observed for . The room-temperature magnetocrystalline anisotropy of Nd1− x Tb x Fe10.5Mo1.5 compounds changes from uniaxial to planar with increasing x content. Based on magnetic measurements, a magnetic phase diagram of Nd1− x Tb x Fe10.5Mo1.5 compounds is constructed. By minimizing the magnetocrystalline anisotropy energy, a theoretical magnetic phase diagram for the Nd1− x Tb x Fe10.5Mo1.5 system is derived, showing a reasonable agreement with the observations. [Copyright &y& Elsevier]

In this paper, the preparation, microstructures and mechanical properties of in-situ (TiB 2 + ZrB 2 )/AlSi9Cu3 composites are investigated by X-Ray diffraction (XRD), optical microscope (OM), scanning electronic microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM) and tensile testing. The composites are fabricated from Al–K 2 TiF 6 –K 2 ZrF 6 –KBF 4 system via melt in-situ reaction technology. The results reveal that the morphology of TiB 2 and ZrB 2 particles is presented in rectangular and nearly hexagonal, and the size of 20–100 nm in the synthesized composites. In addition, the particles are agglomerated as many of “Reinforced Group”, which are distributed along the crystal boundary of the matrix. The silicon phase and secondary dendrite arm spacing of AlSi9Cu3 alloy are obviously changed by the introduction of in-situ particles. The morphology of the silicon phase is presented in rod-shape or needle-shape with the size of about 3–10 μm. The particles affect the formation of dendrites and the size of the secondary dendrite arm spacing is 9.8–20 μm, while it seems to not affect the morphology of the CuAl 2 phase. Tensile testing results show that the tensile strength and elongation clearly increase with the introduction of in-situ particles. Moreover, the tensile strength and elongation reach 265 MPa and 14.8% respectively, with the best reaction time (30 min) and mass fraction of reactants (20wt.%). The mechanical stirring also significantly affected the particles dispersion in the composites. [ABSTRACT FROM AUTHOR]

Abstract: WC–Al2O3 composite powder potentially could be synthesized through milling of WO3–C–2Al mixture. High temperature resulted from reduction of WO3 by Al, activates the reduction reaction of WO3 by C and brings about carbon deficiency in the system which consequently causes the formation of undesirable W2C phase. Hence, addition of excess amounts of C becomes necessary. The aim of the present study has been to find out some appropriate routes for the fabrication of WC–Al2O3 composite powder from WO3–2Al–C mixtures in such a way that the formation of W2C is prevented. Results of high energy milling showed that the mode of reaction in WO3–2Al–C mixture is MSR (mechanically induced self-propagating reaction). In this system, evolution of CO gas and high value of C loss were evidences for the need of excess C. For samples produced via suggested routes, no CO evolution was observed and the amounts of total carbon were constant. These observations showed that the proposed routes have been capable of producing WC phase without the presence of W2C. Mechanism of the reactions in each route has been discussed. [Copyright &y& Elsevier]

Abstract: In order to produce tungsten carbide from its oxide through mechanochemical process, a mixture of tungsten oxide, carbon and aluminum powders was subjected to high energy milling. Excess carbon addition was made in expense of aluminum, so that carbon acts not only as a carbide former agent but also as a reductant. Aluminum and carbon contents of the mixture were altered according to the following reaction: WO3 +(4−1.5x)C+ xAl=WC+(x/2)Al2O3 +(3−1.5x)CO(g). The value of x varied from 0.5 to 1.9 and the effect of Al content on the mechanism of tungsten carbide formation was investigated. Thermodynamic calculations revealed that the amount of Al in the mixture plays a key role. Experimental results showed that at lower Al content in the WO3–Al–C mixture (x =0.5–1.2), reactions proceed through a gradual mode. By increasing Al content (x =1.3–1.6), type of reactions changed to mechanically induced self-propagating reaction (MSR) with no carbothermic reduction reaction of WO3. Further increase of Al content (x =1.7–1.9) resulted in MSR mode reactions consisting of both aluminothermic and carbothermic reactions. Optimum value of x which yields maximum amount of WC was found to be around 1.7. Discussion has been made to elucidate the phase formation types in accordance with the above three reaction modes. [Copyright &y& Elsevier]

Abstract: We report growth by molecular beam epitaxy of a Zn x Cd(1− x )Se/Zn x ′Cd y ′Mg(1− x ′− y ′)Se quantum cascade (QC) structure that was designed for electroluminescence (EL) at ∼4.5μm. The QC active region is comprised of a two-well asymmetric coupled quantum well (ACQW) structure, which was thoroughly investigated to establish the growth conditions for the QC structure. After growth of several ACQW test samples, the conditions for growth were optimized for the QC structure. In-situ RHEED, photoluminescence (PL), high-resolution X-ray diffraction (HR-XRD) and Fourier transform infrared (FTIR) spectroscopy results were used for characterization. The QC structure grown under these conditions exhibited EL at 4.8μm, in excellent agreement with the design value. [Copyright &y& Elsevier]

Abstract: The subsolidus phase relations of the Cu–Ga–N system are studied by X-ray powder diffraction. The phase relations of the binary Cu–Ga system are checked firstly. θ-CuGa2 which belongs to the tetragonal system is determined to be a stoichiometric compound and its thermal expansion is measured by temperature-dependent X-ray powder diffraction from 93 to 523K. The linear temperature dependences of the expansion coefficients along the a- and c-axis and volume coefficients are obtained, α a =(1.97349−3.84678×10−5 T)×10−5, α c =(2.00261−3.96007×10−5 T)×10−5 and α V =(6.01498−3.49098×10−4 T)×10−5, respectively. No ternary compound is found in the Cu–Ga–N system. Cu and its alloys could have some reaction with GaN under the present experimental condition. [Copyright &y& Elsevier]

Abstract: The phase diagram of the Ag–Ga binary system and the phase relations of the Ag–Ga–N system are studied by DTA and X-ray powder diffraction. The equilibrium phase diagram of the Ag–Ga system is reconstructed. Two intermetallic phases are determined in the Ag–Ga system: the Ag2Ga compound and a novel δ-Ag3Ga2 with the composition about 40at.% Ga. The novel phase δ-Ag3Ga2 which is the product of the peritectic reaction Ag2Ga+L↔δ-Ag3Ga2 at 575K is indexed with an orthorhomic lattice with lattice parameters a =6.7276(2)Å, b =3.8840(1)Å, c =3.2200(1)Å and V =84.14Å3. The temperature-dependent lattice parameters of ζ′-Ag2Ga with 28at.% Ga are measured by temperature-dependent X-ray powder diffraction from 93 to 543K. The linear temperature dependences of the expansion coefficients along the direction of a- and c-axis and volume coefficients are obtained, α a =(1.4741+0.0028T)×10−5, α c =(1.1710+9.1349×10−4 T)×10−5 and α V =(4.1167+0.0065T)×10−5, respectively. No ternary phase is found in the Ag–Ga–N system and no solubility of Ag in GaN is observed under the present experimental conditions. [Copyright &y& Elsevier]

The (LaBa)Co2O5+δ thin films were grown on (001) SrTiO3 single crystal substrates by using pulsed laser deposition. Microstructure studies from x-ray diffraction and electron microscopy show that the films have good epitaxial quality with a-axis orientation and sharp atomic interface. Transport property and isothermal magnetoresistance measurements have been used to understand the physical properties of the films with anomalous magnetic phenomena and the largest reported magnetoresistance value of 19% at 40 K. [ABSTRACT FROM AUTHOR]