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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]

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]

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]

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]

Magnesium hydroxide sulfate whisker (MHSH) was used as flame-retarded synergistic agent of intumescent flame retardant (IFR), and to prepare flame-retarded PBS composites. The mechanical performance and flame-retardant properties of composites were investigated. Experimental data showed that an appropriate MHSH loading favored the mechanical performance and flame-retardant properties of composites. When IFR and MHSH loadings were 23 and 2 wt%, respectively, the limited oxygen index value of 39.8% and UL-94 V0 rate of composite could be achieved. The tensile strength increased by 33.3% in comparison with that of composite only prepared by 25 wt% IFR. XRD analysis indicated that the addition of MHSH significantly increased the crystallization of composites. FT-IR analysis demonstrated that P-O-Mg-O-P bonds could be generated during pyrolysis process. TG and cone calorimeter analyses both indicated that the incorporation of MHSH and IFR lowered the flammability of composites by limiting heat and mass transfer. Based on the experimental and analyses data, especially the SEM analysis, possible mechanism was proposed. The combustion products of MHSH and IFR provided a flame shield during combustion process. MHSH played a reinforcement effect in the shield. A more stable three-dimensional intumescent charred layer could not only effectually prevent the melt from dripping but also hinder the diffusion of oxygen and heat into the interior substrate. [ABSTRACT FROM AUTHOR]