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The paper uses X-ray diffraction (XRD) at different temperatures and both imaging and X-rays energy-dispersive spectroscopy (XEDS) in the SEM to examine changes that occur in this high-entropy oxide. The paper was handled by David Cann, one of our Editors whose own research emphasizes ceramics; it is entitled "Phase equilibria and metastability in the high-entropy A SB 6 sb B SB 2 sb O SB 17 sb oxide family with I A i = Zr, Hf and I B i = Nb, Ta." The paper is essentially a classical study of a ceramic material with the twist that these high-entropy ceramics had not been recognized as such until quite recently. [Extracted from the article]

The carbothermal reduction of SiO2 gel containing filter paper (as carbon precursors) in argon was used to prepare SiC nanowires and nanoparticles. The resulting SiC ceramic, as well as the conversion mechanism of carbon/silica composites to SiC nanowires and nanoparticles, have been investigated by scanning electron microscopy (SEM), Transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TG) techniques. XRD and IR studies show that the materials, obtained from reaction at 1550 °C for 1 h in static argon atmosphere, are β-SiC. SEM and TEM reveal that SiC nanowires is single crystal wires with diameters ranging from 50–200 nm and their lengths over several tens of microns. According to thermodynamic analysis, SiC nanowires and SiC nanoparticles in the resulting SiC ceramic are formed by gas-gas reaction of SiO (g) and CO (g). [ABSTRACT FROM AUTHOR]

Numerous catalysts have been studied and developed to catalyze the decomposition of methane and in this paper, an iron slab is selected as the catalyst to obtain stable Fe3C and C2 during the decomposition of methane. We combine ReaxFF MD simulations and laboratory work to investigate methane decomposition and carburization of carbon atoms. The analysis of XRD and TEM confirms the Fe3C formed after the reaction and demonstrates its microscopic morphology. Simulations reveal that the iron slab accelerates the primary decomposition of CH4 in the meantime promotes the synthesis of hydrogen molecules and the whole carburizing reaction mechanism has been characterized by the formation of Fe3C and diffusion of C atoms which has been described with carburizing depth. Finally, the influence of methane concentration is explored and the result shows that an appropriate enhancement accelerates the carburizing reaction while the excessive increase will inhibit it. [ABSTRACT FROM AUTHOR]

The organic functionalization of polyoxometalate (POM) clusters has exhibited increasing superiority for the rational excavation and design of advanced POM-based materials. The architectures of such inorganic–organic hybrids are just like "molecular Lego" toys by virtue of the intermolecular and/or intramolecular interactions. Although numerous novel hybrids have been reported by pioneers, the relationship between organic segments and supramolecular architectures is still ambiguous. In this paper, we focus on the influence from organic bridging ligand to the structural orientation of POM hybrid materials by X-ray diffraction, molecular simulation, and energy calculation. The results indicate that rigid organic bridging ligand possesses a much stronger tendency to form intermolecular interactions than flexible ligand and can improve the electrochemical performance for hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

Dual-phase high-carbon steels are of significant interest in mining industries particularly in comminution and rock handling applications where the strain rate varies from very low to very high. The effect of quasi-static strain rate on the deformation behaviour of austenite-martensite high-carbon low-alloy steel is investigated for compression loading in this paper. Experiments were conducted at different compressive strain rates (2.56 × 10−4 to 2.56 × 10−1 s−1), and the subsequent microstructural evolution was characterised by optical microscopy, X-ray diffraction (XRD), scanning electron microscopy and electron backscatter diffraction (EBSD) techniques to establish the structure-property correlation. The experimental results indicated an increase in the yield strength (σy) with the increase in the strain rate due to the rate-dependent dislocation velocities. The strain hardening rate of the material exhibited a decreasing trend with an increase in the true strain values for all the applied strain rates. XRD results indicated the phenomenon of deformation-induced martensitic transformation (DIMT) to be rate dependent, whereas EBSD results showed an increase in the Kernel average misorientation values with increase in the strain rate. The volume fraction of retained austenite was observed to be decreasing with an increase in the engineering strain values irrespective of the applied strain rate. The microscopic features of the fracture surfaces showed the presence of transgranular cracking at low strain rates, whereas predominant intergranular cracks were found at higher strain rates. TEM results indicated the decrease in the lath martensites with increase in the strain rate. [ABSTRACT FROM AUTHOR]

Semiconductor materials keep occupying an excellent technological position for their importance in building integrated electronic systems. Semiconductor bridge (SCB) with N-type phosphorus-doped silicon material is a new generation of ignition device developed by semiconductor integrated circuit technology. A thermoelectrical model of the ignition device is established in this paper with the consideration of the external capacitor discharge circuit of SCB. The results reveal the thermal properties and electrical properties of the semiconductor device. The time evolution of electric field, current density and temperature distribution during the transient heating process are analyzed. In particular, the temperature distributions of the device show an obvious uneven melting phenomenon; ranging from room temperature to the melting point, the peak temperature points of the SCB transfer versus time, from the edges (0-1.78 ns) to the middle of the bridge (1.78-2.74 ns). The proposed model with specific heavily doped semiconductor material shows that the vaporization fronts tend to originate at the middle of the bridge, rather than the edges. An analysis on the relationship between thermal field and electrical field is conducted, demonstrating that the changes of temperature peak points in SCB are highly relevant to the “flow around” phenomenon in the uneven current density distribution. [ABSTRACT FROM AUTHOR]

In this paper, flower-like Ag nanocrystals and their fractal networks were successfully synthesized by gas-solution interface technique at the surface of AgNO3 water solution with the assistance of ammonium citrate and of gaseous N2H4 used as reductant. The synthesized flower-like silver structure consisted of a large number of petal-like silver nanoplates. They were characterized by scanning and transmission electron microscopy, absorption UV-Vis spectroscopy, and X-ray diffraction. In addition to the standard silver fcc modification, the nanostructures contained the hexagonal polymorph (4H-Ag) in the amount of about 5%. The effect of pH of the solution on the morphology of nanoparticles and on the silver crystal structure was examined. Depending on the time of treatment with gaseous hydrazine, it was possible to obtain either separate flower-like nanoparicles and their fractal networks, or continuous films formed by rather closely packed petal-like nanoparticles. The surface-enhanced Raman scattering effect was observed, and the most intense interaction of laser beam with the silver nanoparticles occurred when the solution side of the synthesized film was irradiated. [ABSTRACT FROM AUTHOR]

A facile, green method for fabrication of conductive ink composed of Ag flakes was developed for use in flexible printed electronics. The Ag flakes were prepared using AgNO3, nontoxic L-ascorbic acid (Vc) and polyvinylpyrrolidone (PVP) serving as a metal salt, reducing agent and capping agent, respectively. The prepared Ag flakes were characterized by XRD, SEM, and TGA. The combination of PVP and FeCl3 was found to be critical for the formation of the Ag flakes, and reaction activity was affected by temperature. Samples obtained at 140 °C were composed of Ag flakes with an average size of 0.94 ± 0.3 μm. A new fabrication method for producing conductive patterns was designed using a syringe with varying dispersion areas, allowing the ink (Ag flakes and organic solvent) to be applied directly onto a flexible photo paper. The conductivity and flexibility of the pattern were experimentally tested under varying reaction temperatures and bending cycles. Increasing contact area and packing density between Ag flakes resulted in an improved conductivity of the bending pattern. After more than 5000 bending cycles, the patterns were sintered at 160 °C and the resistivity increased from 4.6 ± 0.6 to 22.4 ± 0.8 μΩ cm, acceptable values for practical applications. Sample conductive lines drawn by the Ag flake ink exhibited excellent conductive performance and mechanical integrity, demonstrating a promising method for the formation of flexible microelectrodes or electronic devices. [ABSTRACT FROM AUTHOR]

This paper describes the enhancement in stability and electrochromic properties of regioregular poly(3-hexylthiophene) (rrP3HT) polymer films in ambient conditions via ultrasonication of the polymer solution before deposition. The ultrasonicated polymer solution was spin coated onto an ITO substrate, and the electrochromic properties of the resulting rrP3HT films were characterized by UV-Vis spectroscopy, cyclic voltammetry and spectroelectrochemistry. The morphology and crystallinity of the polymer films were measured by atomic force microscopy and X-ray diffraction. Ultrasonication of the polymer solution controlled and increased the intra-chain interaction of the resulting polymer film on an ITO substrate. This method resulted in the polymer film changing colors at a voltage 0.2 V less than an untreated film with concurrent high stability and a fast response switching time of 1-2 s. This method was demonstrated to be a convenient way to lower the applied voltage and to increase the stability of the electrochromic rrP3HT film. [ABSTRACT FROM AUTHOR]

This paper presents results about the influence of the selective laser melting (SLM) process parameters on a FeCr4Mo1V1W8C1 (wt%) alloy regarding microstructure and mechanical behavior. Tailored parameter variation studies were performed to obtain crack-free and highly dense SLM parts. The microstructure was studied using scanning electron microscopy, X-ray diffraction, Auger electron spectroscopy, and scanning transmission electron microscopy. Additionally, the mechanical properties were investigated by compression and tensile tests. The obtained microstructure is composed of complex nanoscale carbides, retained austenite, and martensite. Caused by the fast directional cooling during SLM, a completely dendritic solidification aligned in building direction occurs. Non-equilibrium segregation leads to an orderly phase arrangement of complex carbides at the boundary of the dendrites surrounded by retained austenite and martensite in the center of the dendrites. A strong work hardening behavior was observed, based on an austenite-to-martensite phase transformation (TRIP effect). This effect accounts for the outstanding mechanical properties such as compression strength of 6000 MPa, a 0.2% tensile yield strength of 560 MPa, and an ultimate tensile strength of over 1000 MPa. These findings reveal that SLM is advantageous for the processing of ultra-high-strength FeCrMoVWC tool steel. [ABSTRACT FROM AUTHOR]

In this paper, InAs/ZnS mixed nanocrystals were synthesized by dry high-energy milling approach in the first step. The obtained nanocrystals were characterized from structural point of view by X-ray diffraction analysis and Raman spectroscopy, and from the morphological point of view by scanning electron microscopy. In the next step, the nanocrystals were subjected to wet ultra-fine milling in order to obtain a nanosuspension of chitosan-coated InAs/ZnS nanocrystals with bio-imaging properties. The stability of the nanosuspension was examined by zeta potential and particle size distribution measurements. The prepared nanosuspension was stable with high values of zeta potential. Its optical properties were also studied using UV-Vis and PL spectroscopies. The determined fluorescent properties confirming the potential in bio-imaging applications were verified on cancer cell lines Caco-2, HCT116, HeLa, and MCF7. [ABSTRACT FROM AUTHOR]

This paper reports a new strategy for preparation of 2D molecularly imprinted materials (MIM) through the exploitation of thiol-ene click chemistry. 2D MIM for cholesterol was prepared using cholesterol as the template, acrolyl-modified β-cyclodextrin (acrolyl-β-CD) as the functional monomer, and thiol-modified SBA-15 (thiol-SBA-15) as the supporter. In this method, acrolyl-β-CD molecules were assembled around the templates by formation of template-monomer inclusion compounds. Then the acrolyl-β-CD molecules were anchored to the walls of the mesopores of SBA-15 via the thiol-ene click chemistry. After removal of the template molecules, the resulting recognition sites were formed in the mesopores of SBA-15. TEM, XRD, and N adsorption-desorption analysis results demonstrated that the synthesized MIM had a highly ordered mesoporous structure. Results from FT-IR revealed that acrolyl-β-CDs have been successfully conjugated to SBA-15. The density of β-CDs attached on the MIM is determined by EA and TGA. The equilibrium binding amounts of MIM and non-imprinted materials (NIM) for cholesterol are 53.50 and 25.24 μmol/g, respectively. The 2D MIM exhibited binding affinity and specificity for a group of analytes which have similar size and shape to those of template. The application of the prepared materials as stationary phases in thin layer chromatography was investigated preliminarily. The imprinted materials had higher retention ability for the template than the NIM. The retention factors ( R) of cholesterol on MIM and NIM are 0.62 and 0.81, respectively. The solid phase extraction of cholesterol using MIM as the adsorbent was further investigated. The recoveries of the molecularly imprinted solid phase extraction column for cholesterol were 77.1-94.7 % with relative standard deviations (RSD) of 2.25-6.78 %. [ABSTRACT FROM AUTHOR]

The nucleation and growth of SiC polycrystals around seed crystals restrain the growth of SiC single crystals in the radial direction fabricated by physical vapor transport method in which the ordinary graphite is used as the crucible lid. Therefore, it is necessary to reduce the nucleation and growth of SiC polycrystals around the seed crystals. In order to effectively enlarge SiC single crystals, the authors propose the use of a graphite paper instead of graphite as the lid to restrain the nucleation of SiC polycrystals on the lid. The micrographs of SiC polycrystals on the graphite paper and graphite at the different growth stages show that the nucleation of SiC polycrystals on the graphite paper is more difficult than that on graphite. X-ray diffraction and scanning electron microscope investigations show that the graphite paper possesses high-macroscopic anisotropy , which induced that polycrystals can only grow on the surface of graphite paper and be easily removed. [ABSTRACT FROM AUTHOR]

Natural fibers are particularly interesting from a materials point of view since their morphology has been tailored to enable a wide range of macroscopic level functions and mechanical properties. In this paper, we focus on mussel byssal threads which possess a morphology specifically designed to provide a hysteretic yet resilient large strain deformation behavior. X-ray diffraction studies have shown that numerous natural fibers have a multi-domain architecture composed of folded modules which are linked together in series along a macromolecular chain. This microstructure leads to a strong rate and temperature dependent mechanical behavior and one which exhibits a stretch-induced softening of the mechanical response as a result of the underlying morphology evolving with imposed stretched. This paper addresses the development of a constitutive model for the stress–strain behavior of the distal portion of mussel byssal threads based on the underlying protein network structure and its morphology evolving with imposed stretched. The model will be shown to capture the major features of the stress–strain behavior, including the highly nonlinear stress–strain behavior, and its dependence on strain rate and stretch-induced softening. [ABSTRACT FROM AUTHOR]

In this paper, copper coated carbon nanotubes (CNTs) was synthesized by decomposition of Cu(II) acetylacetonate (Cu(acac)2) in hydrogen atmosphere at 300 °C. The thickness of the copper coating was in nanoscale according to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images, and Raman spectra indicated that certain intermediate bonds were formed between copper and the template CNTs. The crystalline structure of copper and its growth orientation were determined by X-ray diffraction (XRD) and selected area electron diffraction (SAED). The copper coating on CNTs had a face-centered cubic structure and its growth orientation was parallel to $$ (\bar 111) $$ planes. The method developed in this paper had the advantages of simplicity in both process control and experiment equipments, so that it might provide a possibility of large-scale production. [ABSTRACT FROM AUTHOR]

In this paper, we synthesized a new cathode material (CuBiS) by a solvothermal method for high-performance lithium-sulfur batteries. CuBiS with a unique flower structure was characterized using the X-ray diffraction, energy-dispersive X-ray spectrometer, and scanning electron microscopy. It is shown that the CuBiS/S flower exhibits a high initial capacity of 1343 mAh g at 0.2 C, and although a capacity fade in subsequent cycles occurs due to polysulfide dissolution and shuttle mechanism, 487 mAh g at 0.2 C can be retained after 100 cycles with the 90-95 % coulombic efficiency. [ABSTRACT FROM AUTHOR]

In this paper, BiS microflowers have been successfully synthesized via a facile one-pot hydrothermal method and characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray analysis, and X-ray photoelectron spectroscopy. Then the BiS microflowers were deposited on patterned ITO glass substrates by dip-coating to fabricate photodetectors. The photoresponse properties using BiS microflowers as a representative system show a significantly enhanced conductivity and the current-voltage characteristic exhibit ca. 1.7 orders of magnitude larger than the dark current. The response and decay times are estimated to be ~227 and 880 ms, respectively, indicating that flower-like BiS may be an excellent candidate for high-speed and high-sensitivity photoelectrical switches and light-sensitive devices. [ABSTRACT FROM AUTHOR]

Polymer processing generally plays a crucial role in determining the development of microstructure in the fabricated product. In this paper, isotactic polypropylene (iPP) containing 0.1 wt% β-nucleating agent was extruded via a slit die and immediately melt-stretched upon various stretching rates (SR) at the die exit. The microstructure of β-nucleated iPP samples was investigated using two-dimensional wide-angle X-ray diffraction and small-angle X-ray scatterings (2D-WAXD/SAXS) measurements. It is observed that, no matter what SR is, lamellar branching of β-form crystal is formed in melt-stretched samples, which is scarcely reported in open literatures. A method is proposed to calculate the crystallinity of daughter lamellae in β-crystal ( X). It is found that X decreases with increasing SR, indicating that lamellar branching of β-form crystal is restrained by higher SR. Such case should be attributed to the denser-oriented structures (e.g., shish) induced by higher SR, leaving a confined space between adjacent-oriented structures for the growth of daughter lamellae. [ABSTRACT FROM AUTHOR]

The phase relation of Li2O-FeO-P2O5 ternary system under the 95 %Ar + 5 %H2 atmosphere has been systematically investigated by X-ray diffraction (XRD), and there exist 8 binary compounds, 4 ternary compounds, 2 two-phase regions, and 17 three-phase regions. No other new lithium ferrous phosphates can be existed in the Li2O-FeO-P2O5 ternary system under the 95 %Ar + 5 %H2 atmosphere. In this system, the Li1+xFe1-xPO4 solid solution phase with the homogeneous range of −0.15 ≤ x ≤ 0.06 is determined. Their corresponding lattice parameters are obtained by the refinement results, and the results show that the lattice parameters ( a, b, c, V) vary linearly with the increasing amount of excess Li-ion ( x > 0) or with the increasing amount of excess Fe-ion ( x < 0). The phase diagram determined in this paper can provide more information about the phase relation of Li2O-FeO-P2O5 ternary system and serve as a guide for the future investigation of lithium iron phosphates in this system. [ABSTRACT FROM AUTHOR]

Nanograined (grain size 6-15 nm) ZnO films with various Fe content (between 0 and 40 at.%) were synthesized by the novel liquid ceramics method. The films with 0, 0.1, 5 and 10 at.% Fe contain only ZnO-based solid solution with wurtzite structure. The films with 20 at.% Fe contain mainly amorphous phase. The peaks of the second phase (ZnFeO with cubic lattice) become visible in the X-ray diffraction spectra at 30 at.% Fe. Therefore, the overall solubility of Fe in nanograined ZnO films at 550 °C is about 20 at.% Fe. The solubility limit in the bulk is about 1.5 at.% Fe. The recently published papers on the structure and magnetic behaviour of Fe-doped ZnO allowed us to obtain the dependence of Fe solubility in ZnO on the grain size. The overall Fe solubility drastically increases with the decreasing grain size. The quantitative estimation shows that, close to the bulk solubility limit, the thickness of a Fe-enriched layer in grain boundaries is that of several monolayers. [ABSTRACT FROM AUTHOR]

A series of binary CeO-ZrO compounds with the composition of Ce/Zr = 1:1 (molar ratio) were reduced by graphite powders at various reducing temperatures (1173 ≤ T ≤ 1573 K) for 24 h in a self-made reducing device. The reduced products obtained at various T were characterized by X-ray diffraction and Vibration Spectrum. In the case of 1223 ≤ T ≤ 1573 K, the reduced phase is identified as the k-CeZrO phase with the space group of P23, in which Ce and Zr ions are in an ordered arrangement similar to that of the pyrochlore CeZrO and the ordering level between Ce and Zr ions in the pyrochlore-type k-CeZrO phase decreased with the decreasing T. The phase is stabilized without decomposition down to room temperature; the reason is attributed to the reducing atmosphere retention caused by graphite until the end of experiment. In the case of T < 1223 K, a phase transition from k-CeZrO phase to t′-CeZrO phase was observed. The formation of t′ phase is due to the fact that the reducing atmosphere is too weak to severe enough to yield Zr/Ce cation ordered configurations. The graphite reducing mechanism is discussed in the paper. [ABSTRACT FROM AUTHOR]

In this paper, injection-molded isotactic polypropylene (iPP) microparts and macroparts were respectively fabricated by the molds with different thickness under the same processing conditions. Comparative study on microstructure and mechanical property was carried out by means of scanning electron microscopy (SEM), two-dimensional wide-angle X-ray diffraction (2D-WAXD), two-dimensional small-angle X-ray scattering (2D-SAXS), differential scanning calorimetry (DSC) and tensile test. SEM images reveal that the two parts show distinctly different hierarchical structure. An obvious ‘skin–core’ structure is present for the macroparts, while a wide distribution of shish-kebab structure develops in both shear and core layer for microparts, exhibiting a specific ‘core-free’ morphology. 2D-WAXD, 2D-SAXS and DSC results show that microparts have higher orientation degree and crystallinity as compared to macroparts, which are responsible for the remarkably high tensile strength and modulus. Our work provides a good example for better understanding processing structure–property relationship of iPP through tuning their internal microstructure. [ABSTRACT FROM AUTHOR]

Hydrophobic coatings for practical applications demand good durability of hydrophobicity and excellent adhesion. Therefore, the preparation of crosslinked crystalline polymers with perfluoroalkyl side-chains and long alkyl side-chains were proposed. In this paper, the influence of the crosslinking on the crystallization of fluorinated acrylate copolymers was investigated through experimental and molecular dynamic simulation results. According to the FT-IR spectroscopy, XRD data and DSC curves, P(SA- co-HEMA- co-FOEMA) was amorphous, while P(SA- co-FOEMA) and the cured resin formed crystalline polymers with hexagonal packing of alkyl side-chains, and the degree of crystallinity in the cured resin is larger than that in P(SA- co-FOEMA). These phenomenons were further interpreted through the snapshots of the equilibrated systems, the radial distribution function, and the concentration profiles. Intramolecular hydrogen bonds and arrangement of main-chains, corresponding to the embedding of N3300, were considered to contribute to these phenomenons. These findings could be expanded to other comb-shape crystalline polymers for preparing functional surfaces and smart materials. [ABSTRACT FROM AUTHOR]

This paper reports the structural, optical and luminescence properties of Yb 3+/Er 3+ codoped Y 2O 3 phosphor synthesized by combustion method. The prepared phosphor was characterized by X-ray diffraction (XRD). XRD studies confirm the body-centered cubic structure of the phosphor. The optical properties such as diffuse reflectance (DR), photoluminescence and thermoluminescence were studied. DR spectra were used to determine the bandgap of the phosphor. Mechanism of upconversion by two-photon and energy transfer processes are interpreted and explained. The color coordinates were measured and the color tunability was analyzed as a function of the 980 nm excitation source power. Different trapping parameters associated with the glow peak were calculated by various glow curve methods. [ABSTRACT FROM AUTHOR]

In this paper, rapid solidified MgZnY (at.%) alloy powders produced by an inert gas atomizer were consolidated using a severe plastic deformation technique of high pressure torsion (HPT) at room temperature and 373 K. The behavior of powder consolidation, matrix microstructural evolution, and mechanical properties of the powders and compacts were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, microhardness, and tensile testing. As the HPT processing temperature increases, the powders are more plastically deformed due to decreased deformation resistance, grain boundaries are more in equilibrium, powder bonding is enhanced due to increased interparticle diffusion, hence, tensile ductility and strength increases. On the other hand, hardness decreases with the increased processing temperature, due to less dislocation density. [ABSTRACT FROM AUTHOR]

We report in this paper on microstructural, optical and photocatalytic properties of single-phase indium orthovanadates, as a function of doping at lattice sites. The UV-visible spectra of these samples exhibited intense UV-region bands at 250 and 350 nm, besides broad absorption band in visible region (350-700 nm). The wavelength at absorption edge and the intensity of visible absorption showed considerable increase on doping of an impurity, particularly at V or O lattice sites. Also, the samples gave rise to blue-green photoluminescence emission, with overriding bands at ca. 420, 450, 460 and 485 nm, on excitation at 240-420 nm wavelengths. The intensity of these fluorescence bands varied with excitation wavelength and impurity content of a sample. In deviation with several earlier studies, only oxygen and no hydrogen were produced during photocatalytic splitting of water, in the experiments conducted under visible light (>395 nm) and at a pH of ~6.5. The O yield depended on the dispersed metal co-catalyst, impurity content and the addition of methanol as sacrificial reagent. On the other hand, small quantities of hydrogen and no oxygen were evolved on UV-irradiation of pure water using metal/InVO. These results are ascribed to flat band potentials and the doping-induced inter-band donor and acceptor charge trapping states of InVO, the presence of which is revealed by XRD, luminescence and XPS studies. Our study also confirms that the onset of absorption edge may not necessarily correspond to band-to-band energy gap of a semiconducting material. This accounts for some anomalous band gap energies reported earlier for InVO. [ABSTRACT FROM AUTHOR]

This paper reports the preparation of a type of Ag-embedded zeolite crystals as surface-enhanced Raman spectroscopy (SERS) substrates by chemical reduction of Ag-exchanged ZSM-5. Ag ions were loaded into the zeolite framework by ion exchange. Then the exchanged-Ag ions were reduced and metallic silver clusters formed inside the zeolite channel. The resulting Ag-embedded zeolite crystals are characterized by using a number of techniques including X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy to confirm silver formed inside the crystal channel. The fabricated Ag-embedded ZSM-5 zeolite substrates displayed strong and reproducible SERS activity for different Raman probe molecules such as Tris(2,2′-bipyridyl) ruthenium(II) chloride (RuBpy) and rhodamine 6G (R6G). Since silver embedded into the zeolite channel without changing the crystal surface property, the Ag-ZSM-5 zeolite crystal can be used to prepare different SERS-active substrate (SERS-tags), in which different probe molecules may be detected. Such Ag-embedded zeolite substrate would be useful in chemical and biological sensing and in the development of SERS-based analytical devices. [ABSTRACT FROM AUTHOR]

multipurpose acid treatment, which comprises purification, delamination, particle size reduction, and surface modification on milled talc samples, is proposed. Talcs of different origins and composition were studied in order to assess and compare the effects of different acid treatments. Associated minerals were dissolved away by both inorganic and monocarboxylic organic acids, rendering more pure and lower particle size talcs. The main results obtained from hydrochloric acid treatment were purified talcs, having silanol groups onto their surfaces. This treatment allowed the complete removal of carbonates and chlorite from initial talcs, allowing for a length and thickness reduction of talc particles and the change to hydrophilic character by breakage of siloxane bonds. The so-treated talc achieved a purity level enough to be used in plastic and paper industry, paints among other upgraded talc applications. On the other hand, organic acid attacks were able to graft carboxylic groups onto the talc surface. The occurrence of this reaction was verified by independent characterization techniques both direct (Fourier Transform Infrared Spectroscopy, Energy Dispersive X-ray) and indirect (X-ray Diffraction, Scanning Electronic Microscopy, hydrophobicity/hydrophilicity test). [ABSTRACT FROM AUTHOR]

The paper reports the synthesis, structural and high frequency dielectric properties of Ba(ZrTi)OBZT, nanopowders where x = 0, 0.1, 0.2, 0.3. These powders were synthesized using both microwave assisted and conventional heating, with the former requiring lower temperature and shorter times compared to the latter, viz., 700 °C for 30 min versus 900 °C for 5 h. The synthesized nanopowders were characterized using X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy, BET surface area analysis, differential scanning calorimetry and high frequency dielectric measurements. All the microwave synthesized BZT compositions were found to have well crystallized, finer nanoparticles with less agglomeration and higher dielectric permittivity compared to the conventionally prepared powders. The rapidity and less demanding processing conditions associated with the microwave assisted method augers well for the general applicability of the technique for the production of nanocrystalline powders. [ABSTRACT FROM AUTHOR]

A comprehensive study on the synthesis and characterization of gallium selenide (GaSe) has been reported in this paper. Synthesis of gallium selenide (GaSe) from component elements has been carried out in a specially designed and fabricated quartz ampoule, with the help of a rocking furnace. X-ray diffractometry study revealed crystalline GaSe samples belonging to hexagonal system. Raman spectral study emphasized three sharp lines at 208.89, 253.95, and 306.52 cm−1, in good agreement with X-ray diffraction results. Scanning electron microscopy revealed particles of rock like structure, sized in the range 0.4–6 μm. [ABSTRACT FROM AUTHOR]

Anodized titanium-oxide containing highly ordered, vertically oriented TiO2 nanotube arrays is a nanomaterial architecture that shows promise for diverse applications. In this paper, an anodization synthesis using HF-free aqueous solution is described. The anodized TiO2 film samples (amorphous, anatase, and rutile) on titanium foils were characterized with scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. Additional characterization in terms of photocurrent generated by an anode consisting of a titanium foil coated by TiO2 nanotubes was performed using an electrochemical cell. A platinum cathode was used in the electrochemical cell. Results were analyzed in terms of the efficiency of the current generated, defined as the ratio of the difference between the electrical energy output and the electrical energy input divided by the input radiation energy, with the goal of determining which phase of TiO2 nanotubes leads to more efficient hydrogen production. It was determined that the anatase crystalline structure converts light into current more efficiently and is therefore a better photocatalytic material for hydrogen production via photoelectrochemical splitting of water. [ABSTRACT FROM AUTHOR]

The Mg–Ni metastable alloys (with amorphous or nanocrystalline structures) are promising candidates for anode application in nickel–metal hydride rechargeable batteries due to its large hydrogen absorbing capacity, low weight, availability, and relative low price. In spite of these interesting features, improvement on the cycle life performance must be achieved to allow its application in commercial products. In the present paper, the effect of mechanical coating of a Mg–50 at.% Ni alloy with Ni and Ni–5 at.% Al on the structure, powder morphology, and electrochemical properties is investigated. The coating additives, Mg–Ni alloy and resulting nanocomposites (i.e., Mg–Ni alloy + additive) were investigated by means of X-ray diffraction and scanning electron microscopy. The Mg–Ni alloy and nanocomposites were submitted to galvanostatic cycles of charge and discharge to evaluate their electrode performances. The mechanical coating with Ni and Ni–5% Al increased the maximum discharge capacity of the Mg–Ni alloy from of 221 to 257 and 273 mA h g−1, respectively. Improvement on the cycle life performance was also achieved by mechanical coating. [ABSTRACT FROM AUTHOR]

A study of the structural characteristics of the composites [Pb(Fe0.5Nb0.5)O3(PFN)] x -[Cr0.75Fe1.25O3(CRFO)]100− x ( x = 0 (CRFO100), 10, 50, 90, 100) was performed in this work. The compounds PFN100 and CRFO100 were prepared by conventional solid-state method and investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and 57Fe Mössbauer Spectroscopy techniques. The X-ray analysis shows that PFN100 is tetragonal and the CRFO100 phase has a trigonal symmetry. The refinement of all the composites was also performed and discussed in this paper. The Mössbauer spectrum for the composite samples shows a paramagnetic doublet and a sextet probably assigned to a magnetic phase associated to Fe+3. For the sample PFN100, only a magnetic field of 49.5 T (isomer shift (δ) = 0.21 mm/s) was detected. For the composite sample, the δ and Δ are typical of Fe ions at sites of octahedral coordination. [ABSTRACT FROM AUTHOR]

Gd3+ was chosen as a substitute for Bi3+ in BiNbO4 ceramics, and the substitution effects on the sintering performance and microwave dielectric properties were studied in this paper. The high temperature triclinic phase was observed only in the Bi0.98Gd0.02NbO4 ceramics when sintered at 920 °C. Both bulk densities and dielectric constant (εr) increased with the sintering temperature, while decreased with the Gd content. The quality factor ( Q) exhibited a correlation to the Gd content and the microstructures of Bi1− x Gd x NbO4 ceramics. At the sintering temperature of 900 °C, Bi0.992Gd0.008NbO4 ceramics exhibited microwave dielectric properties of εr ∼ 43.87, Q × f ∼ 16,852 GHz (at 4.3 GHz), and its temperature coefficient of resonant frequency (τf) was found to be near-to-zero. [ABSTRACT FROM AUTHOR]

The present paper reports the experimental results on the microstructural and textural characterization of a hot-rolled IF steel. The IF steel was hot-rolled in multiple passes in the austenitic field (1,070 °C) followed by air-cooling. SEM, TEM, and LOM were used to image the microstructure of the material. The global texture was determined by X-ray diffraction (XRD) technique. The mesotexture of selected regions was investigated by electron backscatter diffraction (EBSD). Results show the presence of a diffuse (nearly random) and weak texture in the hot-band that consists of recrystallized polygonal grains and subgrains. The fraction of boundaries with misorientations comprised in the interval 2° ≤ ψ < 15° was found to be lower than 5%. It can be concluded that these low angle boundaries and the presence of subgrains can be associated to the existence of a few areas softened by recovery during or after hot rolling in austenitic field. [ABSTRACT FROM AUTHOR]

In this paper, Ni-doped ZnO (Zn1− x Ni x O, in which 0 ≤ x ≤ 0.05) diluted magnetic semiconductors nanoparticles are prepared by an ultrasonic assisted sol–gel process. Transmission electron microscopy shows sphere-like nanoparticles with an average size of about 25 nm. From the analysis of X-ray diffraction, the Ni-doped ZnO nanoparticles are identified to be a wurtzite structure, but impurity phases are observed when the Ni content x reaches 0.05. Sample structures are further studied by Raman spectra, from which a broad and strong Raman band in the range of 500–600 cm−1 is observed in Zn1− x Ni x O. With the increment of x, wurtzite structures degrade gradually. The magnetic properties are measured using superconducting quantum interference device at room temperature; the Zn1− x Ni x O ( x ≤ 0.02) nanoparticles show ferromagnetism. However, for the sample of Zn0.95Ni0.05O, paramagnetism is observed, which may be ascribed to ferromagnetic–antiferromagnetic competition. [ABSTRACT FROM AUTHOR]

Property modification by blending of polymers has been the area of immense interest. In this paper, the isomorphic blends of two polymers poly (vinyl fluoride) (PVF) and poly (vinylidene difluoride) (PVDF) with different ratios were prepared using solution cast technique. The microhardness studies have been carried out on pure and polyblend specimens at various loads to test the plasticization and hardening effects using Vickers microhardness testing. The X-ray diffraction (XRD) study has been utilized to detect the crystalline and amorphous characteristics of specimens. Thus PVDF acts as plasticizer in the polyblend when the content of PVDF is relatively high as compare to PVF. When the PVF is major component in the polyblend, the microhardness of the blend specimen increases and the isomorphic blend specimens with 50:50 proportion of two polymers exhibit the maximum value of microhardness. Scanning electron microscopy (SEM) micrographs indicate complete chain formation with uniform texture, when the two polymers are blended in equal proportions. The findings of XRD and SEM have been correlated with the microhardness values. [ABSTRACT FROM AUTHOR]

In this paper, quantifications of the austenitic phase in a maraging 300 steel heat treated at different temperatures and periods of time were carried out using the direct comparison method by X-ray diffraction. The influence of taking into account the chemical compositions of austenite and martensite phases in the results by the direct comparison method was evaluated. In order to analyze the instability of austenite under plastic deformation, the quantifications were carried out with and without previous grinding of the samples. The behavior of the austenite volume fraction against aging time at 560°C, 600°C and 650°C were determined. The variation of the martensite lattice parameter with aging time was also analyzed. The results show an increase of the austenite content with aging time at 560°C and 600°C. At 650°C, however, the austenite content present at room temperature decreases and the martensite parameter increases with the aging time above 1 h. [ABSTRACT FROM AUTHOR]

A significant weight loss of copper plate was observed after copper-water vapor interaction near critical point. This leads to the acceleration of the ceramic layer formation on SUS surface during granite-water vapor interaction in the presence of copper. In this paper, we have determined the chemical state of copper at which the mass transfer takes place through reaction with H2 and O2+N2 gas mixture at the different O2 amount. Obtained results indicate that the weight loss of copper plate occurs at Cu2O (+1) state due to a complex processes. The morphology of copper species on the surface of mesh and granite suggests that the Cu2O was dissolved in water vapor and recrystallized on the surface of mesh and granite. Copper species were characterized by X-ray diffraction(XRD), scanning electron microscopy (SEM) equipped with an energy dispersive X-ray (EDX). [ABSTRACT FROM AUTHOR]

This paper embodies the report on the microwave solvothermal synthesizing of nanocrystalline ZnS particles for optoelectronic device. The effect of different parameters such as time, temperature, solvents, molar ratio of zinc and thiourea on the phase(s) formation of nanocrystalline Zinc Sulphide was investigated. The obtained nanosize ZnS materials were characterized by the X-ray diffraction, Optical absorption measurements, TEM and Photoluminescence studies. The crystallite size of the ZnS nanoparticles was estimated from the X-ray diffraction pattern by using Scherrer's formula. The as prepared material was obtained in the cubic phase, which showed a perfect match with the earlier reports. The Optical absorption edge of ZnS were blue shifted from the absorption edge of bulk ZnS. The estimated band gap value of ZnS was 4.01 eV. The ZnS nano materials were coated on nano porous silicon by screen-printing technique. Luminescence studies indicated room temperature emission in the wavelength ranges from 422.6 to 612 nm, which cover the blue emission to red emission. The emitted light that depending on the created pore size from porous silicon and the size of the ZnS nano particles. [ABSTRACT FROM AUTHOR]

In the present work, we report a direct precipitation of nanocrystalline powders of alkaline-earth hydroxyapatites of the compositions, A10(PO4)6(OH)2 (A = Ca, Sr or Ba) from aqueous solutions containing Na3PO4 and MCl2 (M = Ca, Sr or Ba) at 150°C for 2 days and autogeneous pressure under hydrothermal conditions. The products were characterized by X-ray powder diffraction, transmission electron microscopy and scanning electron microscopy. The paper also discusses a convenient and economical hydrothermal route for the extraction of nanocrystalline calcium hydroxyapatite, from fish bone waste. [ABSTRACT FROM AUTHOR]

Hydroxyapatite [Ca10(PO4)6(OH)2], (HA) is similar in composition to bone mineral and has been found to promote new bone formation when implanted in a skeletal defect. However, its use in biomedical applications is limited by its relatively slow rate of biological interaction, and there is also a requirement to improve the success rate of HA implants in younger active patients, particularly where implants will be in place long-term. The addition of silicon (Si) into HA has been demonstrated to enhance the speed, and quality of the bone repair process. This paper describes the synthesis and detailed characterisation of nanocrystalline silicon-substituted hydroxyapatite (SiHA) thin coatings applied to a titanium substrate via a magnetron co-sputtering process. Amorphous SiHA coatings (∼1 μm thick) with varying Si content up to 4.9 wt% were produced before being transformed into crystalline films by heat-treatment. The crystalline coating was characterised by X-ray diffraction (XRD) and infrared (IR) analysis, and confirmed to be a single-phase apatite. The substitution of Si into HA resulted in an increase in both the a- and c-axes of the unit cell parameters, but a decrease in the crystallite size, with increasing Si substitution. This substitution also caused a decrease in the intensities of both the O–H and P–O bands in the IR spectra. Hence, these findings confirmed that the crystal structure of HA was altered with Si substitution. In vitro cell culture work showed that these SiHA thin coatings exhibited enhanced bioactivity and biofunctionality. An increase in the attachment and growth of human osteoblast-like (HOB) cells on these coatings was observed throughout the culture period, with the formation of extracellular matrix. In addition, confocal microscopy revealed that HOBs developed mature cytoskeletons with clear evidence of actin stress fibres, along with defined cell nuclei. [ABSTRACT FROM AUTHOR]

Polarised Raman spectroscopy is a vibrational spectroscopic technique that is used widely for the chemical and physical analyses of materials since it is both non-destructive and suitable for remote analysis. In particularly over the last 40 years, the technique has been developed and applied for the study of molecular orientation distributions in polymers. Compared to other analytical techniques, polarised Raman spectroscopy has the following advantages, (1) quantitative and precise measurement of molecular orientation distributions, and (2) study of these distributions in both the crystalline and amorphous phases. Knowledge obtained from the technique is of both academic and industrial interest to study relationships between microstructure and macroscopic physical properties in polymers. In this paper, polarised Raman spectroscopy is reviewed with regard to the study of molecular orientation distributions in polymeric materials. The basis of polarised Raman scattering is first described, and this is followed by the procedure for obtaining spectra. It is shown how Raman scattering intensities for different polarised scattering geometries can be interpreted to give parameters and functions representing quantitative measures of the degree of molecular orientation. Factors affecting the evaluation of these parameters are also summarised. Finally, the usefulness of the technique is demonstrated by practical applications including a study of molecular orientation distributions in poly(ethylene terephthalate) (PET) fibres. [ABSTRACT FROM AUTHOR]

In this paper thermally stimulated luminescence (TSL) studies of BaB4O7 compound are reported for the first time. The polycrystalline sample of BaB4O7 was prepared by a melting method and the formation of the BaB4O7 compound was confirmed by an X-ray diffraction study. The compound has orthorhombic structure at room temperature. The TSL glow curves of BaB4O7 compound when heated at a constant heating rate of 4°C/s exhibit two thermoluminescence (TL) glow peaks at 110 and 150°C followed by a shoulder around 210°C. The trapping parameters associated with the prominent glow peak of BaB4O7 are reported using isothermal luminescence decay method (ILDM). As a check the trap parameters are also calculated by glow curve shape (Chen's) method after isolating the prominent glow peak by thermal cleaning technique. Our results show a very good agreement between the trapping parameters calculated by the two methods. [ABSTRACT FROM AUTHOR]

Different Zn and Mn-Zn ferrites have been obtained by High Energy Ball Milling (HEBM) from elemental oxides. By varying the rotation speed of vials and main disk, several modes of milling can be obtained. In this paper, the materials prepared by two modes of milling, called shock (S) and high shock (HS), are studied by XRD and Mössbauer spectroscopy. Several mechanisms for spinel phase formation have been proposed. In particular, a reduction of Fe(III) occurs for the S mode, which leads to the formation of a wüstite-type phase which disappears after a long milling time. [ABSTRACT FROM AUTHOR]

In this paper we describe about the synthesis of MgMn2O4 thin films by means of off-axis RF magnetron sputtering and their structural and morphological characterisation realised by means of X-ray diffraction (XRD), micro-Raman spectroscopy and Scanning Electron Microscopy (SEM). We explored different synthesis conditions, namely the substrate temperature, Ts, and the sputtering gas composition and we could observe that well-crystallised films are obtained at Ts = 500°C while the effect of the sputtering gas composition is to affect the structural properties of the films deposited. The thin films deposited always present a crystal structure less distorted with respect to the one of the target material. The possibility of synthesising films of low distorted spinels or even cubic ones may be an interesting way of preparing buffering layers for the growth of isostructural materials such as other spinels or pseudocubic perovskites. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells are currently constructed using a yttria stabilised zirconia electrolyte membrane. However, zirconia has a number of disadvantages associated with its use, such as the high operational temperatures required for it to exhibit acceptable levels of ionic conductivity. Alternative ceramics such as doped cerium oxide show promise as electrolytes capable of operating at reduced temperatures, but introduce additional problems such as electronic conduction and inferior mechanical properties. This paper describes the manufacture and characterisation of a number of prototype electrolytes consisting of a mixture of yttria stabilised zirconia and gadolinium doped ceria. Traditional ceramic processing techniques were used to produce the samples, which were then examined using dilatometry, impedance spectroscopy and X-ray diffraction. Results show a lowering of the ionic conductivity of zirconia with the addition of doped ceria. X-ray diffraction patterns obtained from the samples suggested that this effect could be attributed to the formation of a solid solution of ceria in zirconia. [ABSTRACT FROM AUTHOR]

The potential presence of an amorphous content in OPC clinker and cements is usually overlooked when studying their phase composition. This is largely because of the difficulty in determining amorphous content experimentally. Despite this difficulty, the study of amorphous content and composition in these materials has merit due to the likely effects on the reactivity of the resulting cement. This paper applied the Rietveld method using X-ray powder diffraction data to determine the amorphous content of a number of materials, including clinker, cements and single phases. The cementitious materials were found to contain widely varying, but significant, amorphous contents. The addition of amorphous slag to change the amorphous content by a known amount, gave results as expected from the calculated results for the pure cement and clinker amorphous contents. The results are discussed in relation to other studies published on the issue of amorphous content in cementitious materials. [ABSTRACT FROM AUTHOR]

The majority of lead acid battery failures can be attributed to degradation of the positive active material. In this paper the results from a study to investigate the effects of adding carbon fibre additive to red lead positive paste are presented. The test batteries manufactured were evaluated using capacity and cycle life tests prior to destructive examination and analysis using scanning electron microscopy and X-ray diffraction. Results suggest the addition of carbon fibre to positive paste increases capacity by approximately 20%. Significant improvements in cycle life were also observed. [ABSTRACT FROM AUTHOR]

Cuprous oxide (Cu2O) nano- and microstructures possess unique properties that may find a variety of applications. Environmentally benign synthesis of Cu2O with well-controlled morphology is highly desirable. In this study, Cu2O crystals with tunable shapes are synthesized using cellulose nanofibrils (CNFs) as a shape regulator and the sole reducing agent in aqueous environment. By simply increasing Cu2O precursor concentration, the Cu2O crystals evolved from octahedra to cuboctahedra, and finally cubes, accompanied with increasing size from nano- to microscale. The selection of Cu chelating agent (sodium tartrate or potassium sodium tartrate) affected the crystal growth rate. Transition in the relative intensities of the (111) and the (200) crystalline peaks in their XRD patterns was consistent with the morphology change. During the growth of crystals, CNFs were preferably bound to the {111} crystalline facet. The introduction of KBr to the reaction system produced short hexapods. The resultant CNF-Cu2O hybrids were incorporated into waterborne polyurethane (WPU) films. Even with 0.5 wt% CNF-Cu2O, the WPU film showed significant enhancement in modulus, strength and elongation at break. This work proves the possibility of controlled growth of Cu2O particles aided by CNFs and provides a new strategy for improving the performance of eco-friendly WPU films. [ABSTRACT FROM AUTHOR]