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High Entropy Alloys (HEAs) have become the most researched structural materials in the scientific community during the last decade due to their attributes like excellent strength and wear resistance. In this research, CrCuFeNiZn HEA was prepared using mechanical alloying technique. Further, X-ray diffraction (XRD) and Scanning electron microscope (SEM) analysis of prepared HEA were carried out at various milling time intervals (10 min, 5 h, 10 h, 15 h, 20 h, and 25 h) to determine solid solution formation. Results manifest that CrCuFeNiZn HEA exhibited BCC + FCC (dual phase) structure after 25 h of milling. Moreover, the crystallite size as measured from the XRD analysis for the 25 h milled powder was found to be 32.8 nm and lattice strain at the end of milling is calculated to be 0.428%. SEM-EDS analysis further confirms the homogeneous distribution of the constituting elements in the as-fabricated alloy aggregate. [ABSTRACT FROM AUTHOR]

Clay minerals and sheet silicates are the main constituents of lutites and clays. These materials are relevant in earth science research as well as in economic geology because of the great variety of applications, based on their particular features at different levels of aggregation in mineral assemblages and on the microstructural and structural characteristics of the mineral constituents frequently characterized by micro- and nanocrystalline appearance. Thus, X-ray diffraction is a main tool for fundamental and applied research of these materials. The present review concerns their microstructural research from powder X-ray diffraction data. [ABSTRACT FROM AUTHOR]

The unique physical and chemical properties of silver nanoparticles (Ag NPs) of different sizes and shapes made their synthesis expedient. The most important method of NPs synthesis is the chemical process. However, the disadvantages of this method are the need for specific conditions such as high temperatures, to ensure formation and stability of NPs, as well as use of heavy aromatic solvents. Biosynthesis of NPs is considered advantageous over the traditional chemical approach. In this paper, the first report of the synthesis of silver oxide (AgO) NPs using Trigonella foenum-graecum leaf extract as a reducing agent is presented. The NPs were characterized by X-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TA/DTA), UV, photolumines- cence, SEM, EDX and high resolution transmission electron microscopy (HRTEM). The XRD confirmed the formation of high-purity AgO fine crystals. The average crystal size ranged from 27 to 32 nm as was revealed by HRTEM. From the Tauc plot, the optical band gap of the AgO crystals of 3.3 eV was determined. Thermal analysis provided the optimum temperature for calcination of the AgO NPs to be 400 °C. [ABSTRACT FROM AUTHOR]

Selective laser melting (SLM) of heat-resistant nickel alloy VZh159 is used to show that at constant energy density the key factor determining the texture and the internal stresses is the hatching distance. At multiple increase in the exposure rate and decrease in the hatching distance, the micropore proportion increases exponentially due to enhancement of the dissipation of the laser radiation caused by reflection in the track overlapping zone. [ABSTRACT FROM AUTHOR]

Analysis of published data on the effect of the exposure algorithms, energy, and scanning speed on the geometric characteristics of the molten pool and its fine structure, on the texture and grain structure of metallic materials synthesized by selective laser melting (SLM) is presented. A regression model describing the correlation between the required laser energy density and the powder composition characteristic temperatures during SLM of heat-resistant nickel- and cobalt-based alloys is obtained. [ABSTRACT FROM AUTHOR]

The study analyzed the structural characteristics of carbon nanomaterials obtained at different time parameters of the synthesis based on X-ray diffractometry, Raman spectroscopy, and scanning microscopy. According to the Raman spectroscopy and X-ray scattering data, the crystallite size of nanotubes is estimated to be in the range from 9 to 38 nm. With the synthesis time of 90 minutes, the nanotube crystallite size remains minimal in comparison with other samples, which is confirmed, among other things, by various diagnostic methods. Based on the X-ray diffraction data, the Lc and La crystallite sizes (longitudinal and perpendicular to the direction of the carbon layers) were calculated using the Selyakov-Scherrer formula. The sizes of nanotube crystallites as a result of increasing the synthesis time are in the range of 9-12 nm in the longitudinal direction and 22-38 nm in the perpendicular direction. The diffraction patterns of the samples do not reflect the presence of a significant amount of graphite; the intensity structure is predominantly in the (002) and (004) peaks, which are characteristic of nanotubes. As a result of the use of nanotubes as a modifier component with a synthesis duration from 40 to 90 minutes, an increase in the performance of the composite up to 20-25 % relative to the control sample is observed.

The investigation focused on studying the effect of annealing temperature on the surface morphology and crystalline structure of ZnO films. The Electron-beam evaporation method was used to prepare thin films of zinc oxide (ZnO) on glass substrates. The annealing process was conducted at temperatures of 200°C, 300°C, 400°C, and 500°C for the samples. The phase and crystal structure of the samples were determined using an X-ray diffraction (XRD) device. Additionally, the statistical parameters of surface roughness and morphological analysis of the layer's surface were calculated using an Atomic Force Microscope. The obtained results were analyzed using Gwyddion software and MATLAB coding. The x-ray diffraction analysis confirmed that the samples exhibit a similar pattern to the reference ZnO, and the crystallite size was found to be larger in the samples annealed at higher temperatures compared to those annealed at lower temperatures. The results obtained from both approaches were in excellent agreement, ensuring consistency in the characterization of surface roughness and indicating the presence of crystalline ZnO within the films. Moreover, higher annealing temperatures were observed to result in increased surface roughness, as confirmed by statistical methods and fractal analysis in the AFM analysis. [ABSTRACT FROM AUTHOR]

MoO2 micro-powders with a mean pore size of 3.4 nm and specific surface area of 2.5 g/cm3 were compacted by dry pressing, then pressureless sintered at a temperature of 1000–1150 °C for 2 h or for a sintering time of 0.5–12 h at 1050 °C in an N2 atmosphere. Then, their microstructure evolution for morphology, crystallite, and grain growth were investigated. By sintering at a certain temperature and times, the irregular shape of the MoO2 powders transformed into an equiaxed structure, owing to the surface energy, which contributed to faster grain growth at the initial stage of sintering. The crystallite and grain sizes exponentially increased with the sintering time, and the growth exponent, n, was approximately 2.8 and 4, respectively. This indicates that the crystallite growth is governed by dislocation-mediated lattice diffusion, and the grain growth is determined by surface diffusion-controlled pore mobility. The increase in sintering temperature increased both crystallite and grain size, which obeyed the Arrhenius equation, and the activation energies were determined to be 95.65 and 76.95 kJmol−1 for crystallite and grain growths, respectively. [ABSTRACT FROM AUTHOR]

Clay minerals and sheet silicates are the main constituents of lutites and clays. These materials are relevant in earth science research as well as in economic geology because of the great variety of applications, based on their particular features at different levels of aggregation in mineral assemblages and on the microstructural and structural characteristics of the mineral constituents frequently characterized by micro- and nanocrystalline appearance. Thus, X-ray diffraction is a main tool for fundamental and applied research of these materials. The present review concerns their microstructural research from powder X-ray diffraction data.

The features of the Raman spectra of multilayer carbon nanotubes, which are obtained at different time parameters of synthesis, are analyzed in this study. Carbon nanomaterials are synthesized using chemical vapor deposition (CVD) of hydrocarbons (CxHy) on catalysts (Ni/Mg). Using the Raman spectroscopy, it is found that, at synthesis duration of 90 min, structures are formed that have a minimum crystallite size (in the range from 3 to 11 nm) relative to other objects under study. The change in the intensities of 2D (≈2700 cm–1) and D (≈1350 cm–1) depending on the increasing synthesis time parameter is due to a gradual reduction in the average length of graphene fragments that form the overall structure and final length of the nanomaterial. [ABSTRACT FROM AUTHOR]

Experimental results of microstructural studies of refractory nickel alloys obtained by selective laser melting under different crystallization conditions are systematized. The dendritic (cellular) structure and the distribution of the alloying elements in the volume of dendrite arms are studied by scanning and transmission electron microscopy. The detected microsegregation matches a normal crystallization law and is caused by concentration supercooling. It is shown that the main factors responsible for formation of the fine structure of a track are the orientation growth (epitaxy) and the competitive growth of crystallites. The orientation of the crystallites is transferred not only by the first-order arms but also by the second-order arms, and a specific direction is implemented upon coincidence of the crystallographic orientation of the crystallite with the radial direction of the heat removal. The increasing complexity and the fragmentation of the fine structure are associated with the mechanism of stochastic binarization of the crystallographic orientation implemented upon partial remelting and opening of fragments of cells in the current and preceding layers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ag particles (40–170 nm) supported on α-Al 2 O 3 are composed of multiple crystallites. • Increasing Ag particle size increases the apparent TOF. • EO selectivity nearly constant with Ag particle size (at zero residence time). • Raman bands at 815 and 880 (Ag > 100 nm) cm−1 identified as active oxygen species. • 880 cm−1 band most likely responsible for higher apparent TOF in large Ag particles. In situ Raman spectroscopy and parallel fixed bed reactor studies were conducted under ethylene epoxidation conditions with O 2 at 1 atm and 200 ℃ on unpromoted Ag/α-Al 2 O 3 catalysts with different Ag particle sizes. It was found that for Ag particles of 20–50 nm, the weight normalized conversion rate decreased rapidly with increasing Ag particle size but remained almost constant above 50 nm. On the other hand, the apparent TOF increased with increasing Ag particle sizes in the 20–170 nm studied range, while ethylene oxide selectivity at zero residence time was nearly constant (55 ± 4%). Raman bands at 815 (all Ag sizes) and 880 (Ag sizes > 100 nm) cm−1 were identified and assigned to active molecular oxygen species. The 880 cm−1 species was assigned to a molecular oxygen complex structure stabilized by subsurface oxygen. The presence of the 880 cm−1 oxygen species likely explain the higher apparent TOF in larger Ag particles (>100 nm). [ABSTRACT FROM AUTHOR]

Molded seal devices made of crystalline polymers are widely used in high-pressure hydrogen equipment. A method for evaluating high-pressure hydrogen permeability was recently reported; however, the evaluation cost is extremely high. To select suitable crystalline polymers for molded hydrogen seals or barrier devices, a high-pressure hydrogen permeability prediction method using the polymer structure and its conventional properties is required. In this study, we measured the pressure dependency of the hydrogen permeability of low-density polyethylene (LDPE), high-density polyethylene (HDPE), and polyamide 11 (PA11). We constructed the permeation model for crystalline polymers in terms of the tortuosity induced by their higher-order structures and free volume change in the amorphous region evaluated using PVT method for measuring the relationship between pressure (p), specific volume (v) and temperature (T) in the molten-solid state of a polymer. The results of the pressure dependency of hydrogen permeability were reproduced by the developed permeation model. [Display omitted] • H 2 permeability of LDPE, HDPE, PA11 are measured under high pressure for two methods. • New permeation model for crystalline polymers is developed in terms of the tortuosity. • The results of pressure dependency of hydrogen permeability are reproduced by developed model. [ABSTRACT FROM AUTHOR]

The present work is focused on understanding the role of Ruthenium (Ru) and Yttrium (Y) on the superconducting properties of the A15 Nb 3 Sn intermetallic compound. Ru and Y shows different solubility limit within the Nb 3 Sn matrix. Ru and Y-doped Nb 3 Sn superconducting alloys were prepared through mechanical alloying (MA) route followed by sintering using Field Assisted Sintering Technique (FAST). Analysis by X-ray diffraction demonstrates a significant decrement in crystallite size up to 0.5 wt% for the Ru-doped Nb 3 Sn followed by a significant increment when doping level reaches 1 wt% Ru. This could be the combined effect of structural disorderliness and Ru dissolution within the Nb 3 Sn matrix. While a significant increase in the crystallite size is observed for 0.5 wt% Y-doped Nb 3 Sn and no further change up to 1 wt% Y. This change could be a result of limited solubility of Y within the Nb 3 Sn matrix. Meanwhile, excessive Y plays an important role in the formation of additional flux pinning centers. The critical current density (J c) shows a significant increase for all the Y-doped Nb 3 Sn alloys by a factor of 29 % due to the formation of Y 2 O 3 from the residual Y, which is assumed to serve as additional flux pinning center. The Y 2 O 3 particles was also considered as a possible cause of pinning down of grain boundaries in addition to NbO leading to grain refinement through Zener pinning. Ru-doped Nb 3 Sn alloys also exhibit an increase in J c compared to pristine Nb 3 Sn, but only in concentrations up to 0.5 wt% Ru. At higher applied field, even 1 wt% Ru shows slight increase in J c than pristine Nb 3 Sn. Y-doped samples showed superior functional properties. • The concentration of dopants in Nb3Sn plays a crucial role in defining its functional properties. • The solubility limit of dopants has significant effects on superconducting properties of Nb3Sn. • Yttrium (Y) with limited solubility enhances superconductivity while Ruthenium (Ru) does the opposite. • Formation of additional flux pinning centers led to higher functional behaviour for Y modified Nb3Sn. [ABSTRACT FROM AUTHOR]

This report investigates the effect of substrate and nitrogen (16 keV N+) ion implantation on the structural, morphological, compositional, and electrical properties of V2O5 thin films which are grown by thermal evaporation on various substrates, including glass, Si, and sapphire (termed V2O5:Gl, V2O5:Si, and V2O5:Sp, respectively). Structural analysis showed the formation of the mixed (α, and β-V2O5) phases on all substrates; however, the β-V2O5 phase is highly dominant in the V2O5:G and V2O5:Si samples. A deformation in the β-phase of V2O5 thin film under ion implantation-induced strain results in a change of crystallite size. Irradiation suppresses XRD peaks in relative intensities, indicating partial amorphization of the film with defect formation. Microstructural analysis confirmed the formation of uniform-sized nanorods for V2O5:Si, whereas isolated crystallites were formed for other types of substrates. Thermal conductivity may influence the size and shapes of V2O5 crystallite forms on different surfaces. Silicon absorbs heat more effectively than sapphire or glass, resulting in nanorod formation. A decrease in optical bandgap and electrical conduction has been observed due to increased oxygen vacancies, induced electron scattering, and trapping centres on N+ implantation. The present study thus offers the unique advantage of simultaneous reduction in optical band-gap and conductance of V2O5 thin films, which is important for optoelectronic applications.

MoO2 micro-powders with a mean pore size of 3.4 nm and specific surface area of 2.5 g/cm3 were compacted by dry pressing, then pressureless sintered at a temperature of 1000–1150 °C for 2 h or for a sintering time of 0.5–12 h at 1050 °C in an N2 atmosphere. Then, their microstructure evolution for morphology, crystallite, and grain growth were investigated. By sintering at a certain temperature and times, the irregular shape of the MoO2 powders transformed into an equiaxed structure, owing to the surface energy, which contributed to faster grain growth at the initial stage of sintering. The crystallite and grain sizes exponentially increased with the sintering time, and the growth exponent, n, was approximately 2.8 and 4, respectively. This indicates that the crystallite growth is governed by dislocation-mediated lattice diffusion, and the grain growth is determined by surface diffusion-controlled pore mobility. The increase in sintering temperature increased both crystallite and grain size, which obeyed the Arrhenius equation, and the activation energies were determined to be 95.65 and 76.95 kJmol−1 for crystallite and grain growths, respectively.

The paper investigates the diffusion of Na+ and Cl− in a pore liquid between illite microparticles using the quantum-chemical modeling in Materials Studio. The potential distribution induced by the surface charge of the clay mineral layer, disturbs the uniform distribution of cations and anions observed in the bulk solution. As a result, a layer of immobile cations appears near the microparticle surface. As the distance from the surface grows, the anion concentration grows also, while the potential decreases down to zero. In the appeared double-electric layer, the cation diffusion conditions differ. The particle migration rate in the outer surface of the illite microparticle decreases sequentially for water, anion, cation. [ABSTRACT FROM AUTHOR]

This research aimed to synthesize the new PHF/n-Eu2O3 nanocomposite, characterize its crystalline structures and morphologies, and correlates them with their optical properties. From the XRD patterns of pure PHF, n-Eu2O3, and PHF/n-Eu2O3 samples, adjusted by the Le Bail method, the unit cells and average apparent size of crystallites (43.86, 61.55, 85.59, and 58.05 Å) were obtained. The SAXS measurements showed that the samples of pure PHF and PHF/n-Eu2O3 are polydisperse. The maximum distance of the pair distribution function of pure PHF indicated a particle size of 67.21 nm, and for PHF/n-Eu2O3 it revealed a large nanoparticle formed by two components with diameters of 96.42 and 119.05 nm. Scanning electron microscopy (SEM) and SAXS revealed globular morphologies of nanoparticles of pure PHF, n-Eu2O3, and PHF/n-Eu2O3. The UV-Vis absorption and photoluminescence spectra showed a clear correlation with the ordering of the polymer chains, crystallinity, presence of the β-phase, and morphology of mixed nanoparticles in the nanocomposite. [ABSTRACT FROM AUTHOR]

Impact of the nanosized iron powder on the process of thermal degradation of coal tar distillate was determined by the thermogravimetric analysis. Coal tar distillate was obtained by simple distillation up to 350°C of primary coal tar from the Shubarkol deposit. Iron powder was obtained by electrochemical reduction of iron from sulfate electrolytes at simultaneous impact of high-voltage electric discharge on cathodic zone. Scanning electron microscopy showed that iron powder consists of nanosized particles (30-124 nm) forming aggregates. X-ray diffraction analysis revealed the presence of α-Fe and FeO(OH) phases. The average crystallite size determination was made using Scherrer equation and amounted to 31.7 nm. Obtained iron powder was added to the coal tar distillate in amount of 1% of distillate weight and this mixture was subjected to thermal degradation at heating rate 5°C/min in an inert atmosphere. Processing of the data obtained was carried out using the model-fitting Coats-Redfern method. The values of activation energy were calculated from the linear approximation constructed as a result of processing thermoanalytical data. It was found that the addition of iron powder in amount of 1% to the coal tar distillate reduces the activation energy from 153.98 kJ/mol to 84.48 kJ/mol. [ABSTRACT FROM AUTHOR]

A study was made of the effect of the method of mixing liquid-phase reagents on the size parameters of crystallites and particles of nanocrystalline magnesium hydroxide formed by precipitation from a magnesium chloride solution with a sodium hydroxide solution, and also on the morphology and particle size distribution of magnesium oxide formed by dehydration of Mg(OH)2. Magnesium hydroxide was obtained by reverse precipitation and by mixing the reagents in a free impinging-jets microreactor (FIJMR). Depending on the method of mixing the reagents, the formed magnesium hydroxide crystallites were differently prone to aggregation and agglomeration to form platelike particles. If magnesium oxide particles were produced by heat treatment of nanocrystalline magnesium hydroxide at 500°C, platelike Mg(OH)2 crystallites broke up into MgO nanoparticles, the size of the crystallites of which was comparable to the thickness of the crystallites and particles of the initial magnesium hydroxide. High-temperature (1000°C) treatment of Mg(OH)2 particles gave rise to MgO crystallites, the size of which was comparable to the size of the agglomerates of particles of the initial magnesium hydroxide. [ABSTRACT FROM AUTHOR]

This study aims at designing microwave absorbing composites for controlling electromagnetic (EM) pollution by absorption of EM waves inside the composite material. For this purpose, a light weight and flexible microwave absorber composite was fabricated using reduced graphene oxide (RGO) and W-type barium hexaferrite (BaW) in polyvinylidene fluoride (PVDF) matrix. W-type hexaferrite nanoparticles (BaW) were fabricated by sol–gel auto-combustion method. The fabricated nanoparticles were mixed in PVDF by mechanical grinding. Subsequently, the composites were designed by ultrasonic mixing BaW/PVDF with RGO. The prepared samples were characterized through different techniques for their structural, morphological, and EM properties, as discussed in detail. The X-ray diffractometer results showed the existence of single-phase hexaferrite structure with an average particle size of 48.9 nm. The scanning electron microscope results show that BaW/PVDF is completely embedded in RGO. Dielectric results showed that addition of RGO in BaW/PVDF increases polarization effect, which increases dielectric constant of material. Moreover, RGO decreases the saturation magnetization of composites, which increases the anisotropy constant and hence increases the magnetic loss of material. The composite C3 having RGO to ferrite ratio 15:100 exhibits the maximum reflection loss of −11 dB with broad bandwidth <−10 dB for complete X-band (8.2–12.4 GHz). [ABSTRACT FROM AUTHOR]

Zn2+and Mg2+ions doped Titanium dioxide had been synthesized using a hydrothermal method at 120°C with an annealing temperature at 450°C, including individual Zn2+and Mg2+ ions. In addition, impact of these doping metal ions on the crystallization and phase transition of the Titanium dioxide nanoparticles were discussed by X-Ray Diffraction spectroscopy, Scanning Electron Microscopy, Fourier Transform Infra-Red spectroscopy, UV-Vis spectroscopy and Photo-Luminescence spectroscopy and also by photocatalytic measurements. The presence of anatase type structure in Titanium dioxide nanopowders with high crystallinity and high phase stability in spite of annealing at 450°C significantly specified that the dopants might prevent densification and crystallite growth in Titanium dioxide nanophase by on condition with different boundaries. Furthermore, with a suitable amount of Zn and Mg dopants, anatase grain size of Titanium dioxide powders was reduced. The band gap energy values of Zn2+ and Mg2+ ions doped nano-Titanium dioxide were lower than the pure nano-Titanium dioxide and they exhibited a red shift in the visible region. [ABSTRACT FROM AUTHOR]

Сrystallites in real polycrystals are separated from each other by intergranular space, which affects the effective conductivity of polycrystals. This effect increases with decreasing crystal size. A method for predicting the effective conductivity of polycrystalline media, taking the intergranular space into consideration is developed. The method is constructed using the polycrystal model in which crystallites are considered to be inhomogeneous, consisting of a uniform crystalline anisotropic core and a uniform isotropic shell. In this model, the role of the intergranular gaps is played by crystallite shells. The effective polycrystal conductivity is calculated using the generalized effective-field approximation; the effective medium conductivity is taken as the reference parameter of the medium; i.e., the self-consistent solution method is used. Based on the developed method, a formula for the effective conductivity of polycrystals depending on the conductivity tensor of the crystalline core, shell conductivity, and the core volume fraction in crystallites is derived for the case of spherical crystallites with spherical shells. This formula is applied to particular cases of a polycrystalline medium, i.e., a polycrystal with similar crystallites with isotropic core; in this case, the expression for the effective conductivity is identical to the classical Maxwell–Garnett formula; polycrystals with similar crystallites with anisotropic cores at identical orientations of their crystallographic axes; polycrystals with similar crystallites with anisotropic cores at the uniform distribution of orientations of their crystallographic axes in space; and polycrystals with conductive crystallite cores and absolutely nonconductive shells. In the latter case, the effective polycrystal conductivity vanishes, which is completely consistent with the physical meaning. [ABSTRACT FROM AUTHOR]

The stable EPR signal produced by ionizing radiation in crystalline D-mannose (C6H12O6) and separated from cranberries (Vaccinium oxycoccus) was studied. The isothermal heating of irradiated sample at 95°C for 10 minutes (melting point of D-mannose is 132°C) resulted in the modification and simplification of the EPR signal involved. The isotropic quartet has been recognized in the EPR signal of heat-treated sample. Molecular structure of the isotropic quartet identified in the complex EPR signal of D-mannose crystallite is proposed.

The aim of this research was to analyze the crystallites of poly(9,9'-dihexylfluorene) (PHF). The pristine polymer was synthesized through the Suzuki cross-coupling polycondensation and the reprecipitation method. Through XRD measurements it was possible to determine the semicrystalline diffraction pattern of the polymer which after the structural adjustment by Le Bail method showed orthorhombic unit cells and crystallites with average sizes of 43.86 Å. Scanning electron microscopy (SEM), revealed spherical nanoparticles morphology with average diameters equal to 69.20 nm. The possible relationship between the fluorescent properties and the parallel alignment of the chains in the crystallites was determined through the absorption spectra in UV-Vis and photoluminescence. [ABSTRACT FROM AUTHOR]

The entire world is facing an alarming situation of energy demands and environmental pollution. Single-layer fuel cells are attractive in the era of renewable energy. Developing the materials for single-layer fuel cells (SLFC) is challenging to overcome the low electrical conductivity and polarization losses. In the present research work, novel nanocomposites materials Li 0.1 Ni 0.6 Zn 0.3 O 3-δ (LNZ) have been synthesized by solid-state techniques and Sm 0.2 Ce 0.8 O 2-δ (SDC) via co-precipitation route. Additionally, the effect of 20 wt% of single (Na), binary (Li: Na), and ternary (Li:Na:K) alkali carbonates on the performance of SDC composite material have been analyzed. All novel nanocomposites LNZ + SDC, LNZ + N-SDC, LNZ + LN-SDC, and LNZ + LNK-SDC were milled with 60:40 ratios respectively. Composite material based on 60 wt% LNZ and 40 wt% LN-SDC showed maximum mixed electronic and ionic conductivity of 2.29 Scm−1 at 600 °C with power density of 435mWcm−2. The structural and morphological proprieties of prepared nanocomposite materials were studied using X-Ray diffraction and Scanning electron microscopy respectively. The average crystallite size of 34 nm was observed with LNZ + LN-SDC composite material. The conductivity measurements were done using four-probe techniques and results showed the immense potential of prepared materials for SLFC application. • Alkali carbonated has been developed for one component electrolyte-free fuel cell. • Crystallite size was found to be <100 nm. • The mix conductivity was achieved 2.29 Scm−1 for LNZ + LN-SDC. • The maximum power density was obtained 435 mWcm−2 for LNZ + LN-SDC. [ABSTRACT FROM AUTHOR]

High-energy milling process on ceramic material was analyzed, it process generate modifications on morphology and particle size, the process showed the last one relation with the crystallite size, about of structural analysis Rietveld refinement let identify anisotropy with the variations on crystalline planes and deformations occasioned by milling process, the particle size decrease with the process, similar tendency was observed on the images obtained by Scanning Electronic Microscopy, an result in this study was the variation on magnetization without chemical reaction under non-stoichiometric conditions and the agglomerates sizes observed on samples it is by process.

During the self-catalyzed GaAs nanowire growth formation of parasitic GaAs crystallites is observed. The reasons for crystallite formation are explained on the base of Monte Carlo simulation results. During simultaneous deposition of gallium and arsenic on the GaAs(111)B substrate coated by a silicon oxide film, liquid gallium droplets nucleate on the oxide surface. After nucleation, droplets enlarge in size with time and etch the oxide layer. Formation of GaAs crystal structures becomes possible only after the Ga droplet contacts underlying crystal substrate. It is shown that excessively high arsenic and gallium deposition rates lead to the crystallite formation at the initial growth stage. The GaAs crystallites collect part of the deposited gallium and arsenic decreasing their surface concentration, thereby, adjusting the growth conditions for the nanowire growth. Therefore, during the self-catalyzed GaAs nanowire growth the self-regulation of growth conditions takes place. [ABSTRACT FROM AUTHOR]

Noble metals (Ru, Os, Rh, Ir, Pd, Pt, Ag, and Au) are known for their extraordinary oxidant-resistant behavior, good electrical and thermal conductivity, high work function, and brilliant luster. All occur in close-packed crystal structures: Ru and Os in hexagonal close-packed (hcp) and the rest in face-centered cubic (fcc) structures, both possessing high-symmetry structures and, therefore, a high degree of stabilization. Numerous studies in the literature have attempted to stabilize these metals away from their conventional crystal structures with the aim of realizing new properties. While obtaining conventional fcc metals in hcp structure or vice versa has been the subject of most studies, there are also examples of fcc metals crystallizing in lower-symmetry structures such as monoclinic. The nonnative crystal structures are generally realized during the crystallite growth itself, with a few exceptions in which a posttreatment was required for lattice transformation. In most cases, the new crystal structures pertain to the nanometer-length scale in the form of nanoparticles, nanoplates, nanoribbons, and nanowires, but there are good examples from microcrystallites as well. In this article, we review this active area of research, focusing on ambient stable crystal systems with some account of their interesting properties as reported in recent literature. [ABSTRACT FROM AUTHOR]

The stable and complex EPR signals produced by the action of ionizing radiation on crystalline L-sorbose (C6H12O6) separated from rowan berries (Sorbus aucuparia) were studied. Isothermal heating of the samples at the temperature close to the melting point of L-sorbose (140°C) results in the modification and simplification of the EPR signal involved. In the EPR signal of heated L-sorbose, the isotropic quartet was distinguished. In the differential spectrum obtained by subtraction of normalized spectra of unheated and heated L-sorbose, the isotropic doublet was identified in addition. The DFT fitting offers the probable assignment of the EPR signals to specific radical structures.

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