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The effect of 2MeV energy electrons with fluences from $0.5\times 10^{17}$ to $4.0\times 10^{17}$ electron/cm² on the crystal structure, surface morphology, absorption spectrum, band gap, Raman spectrum and microhardness of ZnS crystal was investigated. The crystal structure of ZnS is face-centered cubic with space group F-43m. Upon irradiation with a fluence of $4\times 10^{17}$ electron/cm², the unit cell parameter decreased by 0.0195Å, and the coordinates of the Zn${}^{+2}$ ions were changed. Irradiation with fluences ranging from $0.5\times 10^{17}$ to $4\times 10^{17}$ electron/cm² increased crystallite size from 20nm to 28nm. The study of the surface morphology of the ZnS single-crystal revealed that irradiation caused a reduction in both the width ($R_a$) and height ($R_z$) of the surface roughness. The band gap of the ZnS single-crystal decreased from 3.521 to 3.506eV when irradiated with fluence electrons from $0.5\times 10^{17}$ to $2.5\times 10^{17}$electron/cm². Raman spectrum observations showed an increase in the longitudinal optical (LO) mode peak (350cm${}^{-1}$) intensity following the irradiation of ZnS single-crystal with electrons. The microhardness of the ZnS single-crystal showed an exponential increase by 20% when irradiated with fluences from $0.5\times 10^{17}$ to $2.5\times 10^{17}$electron/cm².

Vinylporphyrins containing one vinyl group at the pyrrole or benzene ring and their complexes with Cu²⁺ and Zn²⁺ have been obtained by the Wittig reaction. The compounds obtained were characterized by physicochemical methods. X-ray diffraction analysis of 5-(4-vinylphenyl)-10,15,20-triphenylporphyrin has been carried out. It is likely that the inclusion of the vinyl group is accompanied by weak electron effects on the macrocycles. The radical-induced copolymerization of meso-tetraphenylporphyrin monomers with the vinyl group in a benzene or pyrrole ring and their copper and zinc complexes with styrene and methacrylate was studied. Porphyrin comonomers decrease the overall polymerization rate and the number-average molecular weight of the products formed compared with the weight of polystyrene obtained under similar conditions. The main reasons for termination of chain growth by vinylporphyrins were revealed and some quantitative parameters of these reactions were obtained. IR and electronic absorption spectra of porphyrin-containing copolymers are discussed. According to the ESR spectra, the copper-containing centres in the copolymers are fairly remote from each other, and the metal-containing polymeric systems are magnetically dilute. The spectral luminescence properties of solutions of zinc 5-(4-vinylphenyl)-10,15,20-triphenylporphyrin–methyl methacrylate copolymers with various contents of porphyrin groups were studied. It was shown that a new long-wave band appears in the absorption spectra of the copolymers, the intensity of which depends on the copolymer composition, and the quantum yield of fluorescence decreases with increasing molar fraction of porphyrin groups.

X-ray diffraction patterns of melt-spun Fe-Cu-Nb-Si-B (FINEMET-type) alloys reveal that crystallites of Fe₂Si and Fe₃B phases with average sizes of 15(5) and 20(2) nm are present in the surface layer of thickness ≈ 10 Å and these nanocrystallites occupy 5–10% of the total volume. The results of an elaborate analysis of the high-resolution electrical resistivity data taken in a temperature range from 13 K to 300 K and their discussion in the light of existing theories demonstrates that the enhanced electron–electron interaction (EEI), quantum interference (QI) effects, inelastic electron–phonon scattering, coherent electron–magnon (and/or electron-spin fluctuation) scattering are the main mechanisms that govern the temperature dependence of resistivity. Of all the inelastic scattering processes, inelastic electron–phonon scattering is the most effective mechanism to destroy phase coherence of electron wavefunctions. The physical quantities such as diffusion constant, density of states at the Fermi level and the phase-breaking time, determined for the first time for the alloys in question, exhibit a systematic variation with the copper concentration.

The crystal structure and magnetic properties of (Ru_1-xSn_x)Sr₂EuCeCu₂O_z and Ru(Sr_2-xLa_x)EuCeCu₂O_z(0≤x≤0.1) samples have been investigated to shed light on the doping-induced changes in the magnetic properties of Ru-1222 system. We show that La substitution for Sr leads to an increase in the temperature where the ferromagnetic component is observed and a moderate suppression of the ferromagnetic component whereas Sn substitution for Ru results in a significant decrease of the volume fraction of the ferromagnetic phase as well as a decrease in the magnetic ordering temperature. The experimental results are discussed in connection with the structural data studied by Rietveld refinement of the x-ray diffraction data.

The structure of xFe₂O₃·(100-x)[3B₂O₃·BaO] system with 0≤x≤50 mol% was studied by DTA, X-ray diffraction, density, optical microscopy and EPR measurements in vitreous and partial crystallized state, the samples being obtained by under cooling method. The data obtained show that, by melting the samples at T_e = 1200°C or T_e = 1250°C, glasses for x≤35 mol% were obtained, and the forming of crystalline microprecipitates of Fe₂O₃ in the sample with x = 50 mol%. It was also established that the thermal treatment at 565°C without and in the presence of magnetic field of 0.7 T is influencing the forming and the development of the Fe₂O₃ microcrystals in samples with x≥35 mol%. The samples melted at T_c = 1200°C and T_c = 1250°C were studied by magnetic susceptibility measurements which evidenced similar results with those obtained by EPR. Also, the magnetic measurements show that for the thermal untreated samples the iron ions participate at superexchange interactions for x≥5 mol% and for x≥10 mol%, respectively.

A molecular dynamics model was developed to search for stable copper clusters with up to 60 atoms by Gupts empirical potential based on the second-moment approximation to tight-binding model (TB-SMA). We found that isomers do not emerge until the clusters have more than 7 atoms, getting more for clusters with 30~52 atoms, and the magic number, 13, 19, 23, 26, 28, 32, 38, 43, 46, 49, and 55 have ground clusters with higher symmetry and have few isomers.

The geometries and energies of small silicon monohydride clusters (Si₂H–Si₁₀H) have been systematically investigated by density functional theory (DFT) scheme with DZP++ basis sets. Several possible geometric arrangements and electronic states have been considered for each cluster. The results on Si₂H–Si₄H are in good accordance with previous ab initio calculation. The geometry of ground state of Si₂H is found to be a bridged C_2v structure, and Si₃H to be a bridged C_2v, while Si₄H a non-bridged C_s symmetry with ²A′ state. The non-bridged geometries of ground state of Si₅H–Si₁₀H have been found to be corresponding to C_2v(²B₁), C_2v(²B₁), C_5v(²A₁), C_s(²A^′′) (have two types), C₁ (not symmetry), and C_s(²A′), respectively. The results on Si₅H, Si₆H, Si₈H and Si₉H are different from previous calculations. Compared silicon clusters (Si_n) with silicon monohydrides (Si_nH) clusters, the addition of a single hydrogen atom cannot cause great changes in the ground state geometries of Si₂, Si₃, Si₄, Si₇, Si₉, and Si₁₀ clusters, while in the ground state geometries of Si₅, Si₆ and Si₈ clusters the change is great. The dissociation energies calculated indicates that Si₄H, Si₇H, and Si₁₀H clusters are less stable than others.

The non-monotonic relationship of T_c with the number of Cu-O planes (n) per unit cell for compounds of Tl₂Ba₂Ca_n-1Cu_nO_2n+3 (n=1, 2, 3, 4 and 5) is investigated from the reaction between different structural blocks. The unit cell of the Tl superconductors is treated as two blocks: the perovskite block where the Cu-O planes are located and the rock salt block, which is considered as a charge-reservoir. A model was used to calculate the combinative energy of the two blocks. It is found that the combinative energy between the two blocks is closely related to the value of T_c. The relation demonstrates an interesting way to understand the nonlinear change of T_c with the number of Cu-O planes in the layered superconductors. This means that the interaction between the two blocks plays an important role in superconductivity. The results are somewhat different from that of another Tl-system superconductor, Tl₂Ba₂Ca_n-1Cu_nO_2n+4, with 4 superconductive compounds.

The structure and the dynamics of the gas-liquid phase interface of the three-dimensional Lennard-Jones (12-6) particle system are studied using nonequilibrium molecular dynamics simulation. Heat flux maintains the system into a gas-liquid coexisting state with a steady interface. In the steady state, the interface shows an asymmetric structure and this is well described by a free energy density model with an asymmetric double-well form. When the system approaches to the steady state, a gas of the temperature profile appears between each phase and the gap value is relaxed to that in the steady state following for large t. It is observed that heat resistance exists in gas-liquid interface in this scale.

Nanocrystalline Mn_0.6Zn_0.4Fe₂O₄ particles are synthesized by a phase transformation method. The crystal structure of these particles is that of spinel MnZn ferrite. The average particle size is about 50 nm and the grain size is about 11 nm. Magnetic measurements show that the saturation magnetization at 120 K is ~80% larger than that at 300 K, and imply that the majority of the nanoparticles are superparamagnetic from 65 to 300 K.

Silicon oxycarbide (SiCO) thin films were prepared by the RF reactive sputtering technique on n-type silicon substrates with the target of sintered silicon carbide (SiC), and high purity oxygen was used as the reactant gas. The as-deposited films were annealed at temperatures of 600^°C, 800^°C, and 1000^°C under nitrogen ambient, respectively. The films were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and photoluminescence (PL) spectrophotometer. The results show that annealing temperature plays an important role in the structure and photoluminescence of the films. The temperature 600^°C is the most favorable annealing temperature for SiO₂ crystallization and the formation of 6H-SiC crystal phase in the SiCO films. The intense PL peaks located at 375 nm and 470 nm are observed at room temperature. The origin of the PL was discussed.

The structural characteristics of Bi_2-xPb_xSr₂CaCu₂O_8+y(Bi-2212) and Bi_2-xPb_xSr₂Ca₂Cu₃O_10+y(Bi-2223) with x changing from 0 to 0.8 were studied by X-ray diffraction and Rietveld refinement. By careful calculation of chemical bond lengths and angles, it is found that there exists a fixed triangle on the Cu–O planes in the two systems, and then makes the Cu–O planes stable. The fluctuations of this fixed triangle were investigated, and it is found that there is a close relationship between it and T_c's. In addition, we discussed the origin of this special local structure. It may be caused by the interaction between the perovskite block and the rock salt block in a unit cell, which may play an important role in the mechanism of high temperature superconductivity.

Polycrystalline samples of $({\mathrm{\text{Ru}}}_{0.9}{\mathrm{\text{Nb}}}_{0.1}){\mathrm{\text{Sr}}}_2({\mathrm{\text{Gd}}}_{1.34-x}{\mathrm{\text{Nd}}}_x{\mathrm{\text{Ce}}}_{0.66}){\mathrm{\text{Cu}}}_2{\mathrm{\text{O}}}_z$$(x=0-0.67)$ have been synthesized and characterized by X-ray diffraction (XRD), electrical resistivity, thermoelectric power and magnetization measurements. Resistivity measurements revealed that the onset transition temperature $(T_{\mathrm{\text{co}}})$ decreased slightly from $T_{\mathrm{\text{co}}}=40\mathrm{\text{K}}$ for $x=0$ to $T_{\mathrm{\text{co}}}=22\mathrm{\text{K}}$ for $x=0.67$. Magnetization measurements showed that the partial substitution of $\mathrm{\text{Gd}}$ by $\mathrm{\text{Nd}}$ leads to a significant decrease in the magnetic ordering temperature. A suppression of the weak ferromagnetic component of the field-cooled (FC) magnetization with $\mathrm{\text{Nd}}$-doping content was also observed for the samples with $x\ge 0.34$. The changes in the superconducting transition temperature, the magnetic ordering temperature and the weak ferromagnetic component of the FC magnetization are discussed in conjunction with the change in hole concentration and the local structural changes in the Ru sublattice induced by $\mathrm{\text{Nd}}$ doping, based on the Rietveld refinements of the XRD data.

Our present work is based on the density functional theory (DFT) studies of TiO₂ crystals doped with V impurities. Both rutile and anatase structures have been considered within the present research and different defect concentrations have been used as well. Our calculations reveal equilibrium geometry of the system showing atomic rearrangement around the point defect being mainly inward with respect to the impurity. Magnetism and electronic structure based on the density of states (DOS) patterns for both rutile and anatase crystals have been obtained and discussed in detail. It is shown that local magnetic moments arise mainly from the 3d states of the impurity atom with some admixture of 2p states from the vanadium-nearest O atoms.

This paper studies the effects of heating rate 4 × 10${}^{11}$ K/s, 4 × 10${}^{12}$ K/s, 4 × 10${}^{13}$ K/s; impurity concentration of Cu on Ni${}_{1-x}$Cu${}_x$ bulk with x = 0.1, x = 0.3, x = 0.5, x = 0.7; atom number (N), N = 4000 atoms, 5324 atoms, 6912 atoms, 8788 atoms at temperatures (T), T = 300 K; N = 6912 atoms at T = 300 K, 400 K, 500 K, 600 K, 700 K, 800 K; N = 6912 atoms at T = 600 K after time annealing temperature (t), t = 500 ps on the structure, crystallization temperature and crystallization process of Ni${}_{1-x}$Cu${}_x$ bulk by molecular dynamics (MD) method with interactive embedding Sutton–Chen (ST) and periodic boundary conditions. The structural characteristics were analyzed through radial distribution function (RDF), energy total (E${}_{\mathrm{\text{tot}}}$), size (l) and common neighborhood analysis (CNA) method; temperature (T), crystallization temperature (T${}_g$), crystallization process through relationship between E${}_{\mathrm{\text{tot}}}$, T. The results showed Ni${}_{1-x}$Cu${}_x$ bulk and links Ni–Ni, Ni–Cu, Cu–Cu always exist in 03 types structures: FCC, HCP, Amor. When time annealing temperature increases then Ni${}_{1-x}$Cu${}_x$ bulk moves from a crystalline state to an amorphous state. When increases impurity concentration of Cu in Ni${}_{1-x}$Cu${}_x$ bulk, then the structure unit number FCC, HCP decreases and then increases, structure unit number Amor increases and then decreases. When atom number (N) increases, decreasing T and increasing time annealing temperature lead to structure unit number FCC, HCP increases, Amor decreases and structural, crystallization temperature, crystallization process of Ni${}_{1-x}$Cu${}_x$ bulk change.

Molecular dynamics (MD) simulation is applied to investigate the structural characteristics of Al₂O₃–SiO₂ system with the Al₂O₃ content at 60 mol.% (Mullite — 3Al₂O${}_3\cdot$2SiO₂). MD models containing 5250 atoms in cubic box with periodic boundary conditions are constructed at 3500 K in 0–100 GPa pressure range. The Born–Mayer–Huggins potential is applied in this study. Based on the cluster analyzes and MD data visualization technique, the structural characteristics of Mullite melt, such as the short-range and intermediate-range order, the local environments of oxygen and network structure will be clarified. Under compression, the Al–O bonds are broken, leading to incorporation of Al atoms into Si–O subnet through both nonbridging oxygen (NBO) and bridging oxygen (BO), forming –Al–O–Si-network (Al–O–Si, Si–O–Al₂, Si₂–O–Al, Si–O–Al₃, Si₂–O–Al₂ and Si₃–O–Al). The degree of polymerization (DOP) of the silica network and alumina network increase with pressure and the DOP of SiOx-network is lower than that of AlO${}_x$-network under compression. The statistics of corner, edge and face-sharing bonds between two adjacent TO${}_x$ units (T is Si, Al; x = 3–7) as well as characteristics of all type OT${}_y$ linkages (y = 2–6) are investigated in detail. Structural and compositional heterogeneities are clarified via analysis of structure and size distribution of TO${}_x$-clusters.

We adopted the first-principles calculations within density functional theory (DFT) to investigate the structures, elastic, and electronic properties of ternary TiNi-X alloys with different four main-group elements by using the CASTEP code. The lattice constants and volumes increase gradually from C to Pb. The mechanical stability has been discussed by utilizing the criteria. All alloys are mechanically stable except TiNiPb. The values of Young’s modulus gradually decreased. Oppositely, the values of $B$/$G$ and $\nu$ are increased, respectively. The ductility/brittleness of alloys is distinct. In addition, the width of pseudogap is gradually decreased, which is consistent with hardness, showing that the covanlency of TiNi-X alloys is decreased. Similarly, these properties of the remaining alloys are also discussed and results are stated in the paper.

Titanium (${\mathrm{\text{Ti}}}^{4+}$)-doped nanoparticles of the type ${\mathrm{\text{Zn}}}_{0.94}{\mathrm{\text{Cd}}}_{0.06-x}{\mathrm{\text{Ti}}}_x\mathrm{\text{O}}$ [$x=0.0$, $0.03$] are reported in this study. The samples were synthesized by citric acid assisted sol–gel auto combustion (SGAC) method. The samples are characterized by X-ray diffraction (XRD), Raman, Field emission scanning electron microscopy (FESEM), Energy dispersive analysis of X-rays (EDAX) and Fourier transform infra-red (FTIR) techniques for structural studies. Further, for optical properties, UV-Vis technique has been used. In addition, samples were studied for dielectric properties. Room-temperature XRD data study reveals the sample formation with wurtzite hexagonal structure exhibiting space group $P{6}_3$mc also confirmed from Rietveld refinement of XRD data. Raman spectra displays characteristic active phonon modes in pristine ${\mathrm{\text{Zn}}}_{0.94}{\mathrm{\text{Cd}}}_{0.06}\mathrm{\text{O}}$ and doped ${\mathrm{\text{Zn}}}_{0.94}{\mathrm{\text{Cd}}}_{0.03}{\mathrm{\text{Ti}}}_{0.03}\mathrm{\text{O}}$. UV-Vis diffused reflectance spectroscopy analysis infer bandgap values of 3.14 and 3.12 eV for ${\mathrm{\text{Zn}}}_{0.94}{\mathrm{\text{Cd}}}_{0.06}\mathrm{\text{O}}$ and ${\mathrm{\text{Zn}}}_{0.94}{\mathrm{\text{Cd}}}_{0.03}{\mathrm{\text{Ti}}}_{0.03}\mathrm{\text{O}}$, respectively. The dielectric studies confirmed high dielectric constant for ${\mathrm{\text{Zn}}}_{0.94}{\mathrm{\text{Cd}}}_{0.03}{\mathrm{\text{Ti}}}_{0.03}\mathrm{\text{O}}$ compared to pristine ${\mathrm{\text{Zn}}}_{0.94}{\mathrm{\text{Cd}}}_{0.06}\mathrm{\text{O}}$. A non-Debye character with spread of relaxation times was witnessed from impedance study.

Light trapping is of great importance in many applications including photodetectors and solar cells. Silicon-based structures and hybrid devices were designed and studied to reduce reflection, thus enhance light trapping. The typical pillar array was analyzed concerning the pillar radius and distance between pillars first. The result showed that light reflection could be reduced from the range of 0.35–0.45 to the range of 0–0.3 with wavelength from 400 to 700 nm. What should be noted is that optimal size for light trapping changed when wavelength varied. Furthermore, hybrid structure was designed to increase light trapping. The results showed that the structure with random quantum dots (QDs) covering pillar array coated with two-dimensional (2D) material is an effective way to confine the light reflection under 0.1, thus promoting light trapping.

The influence of a single phosphorous impurity on structural and electronic properties of spherical, diamond-like, hydrogen-passivated, ultrasmall Si${}_{29}$H${}_{36}$, Si${}_{34}$H${}_{36}$, Si${}_{59}$H${}_{60}$ and Si${}_{87}$H${}_{70}$ nanocrystals with silicon core diameters of 0.88, 1.03, 1.26 and 1.58 nm was studied by density function theory calculations. In this ultrasmall length scale, the dependence of structural deformation and electronic properties with gradually increasing sizes has not been practically investigated. A detailed analysis of the structural deformation and charge distribution initiated by the presence of the impurity is conducted to understand how structural change occurs within this length scale, where quantum confinement effects become predominant. The Si${}_{28}$P${}_{\mathrm{\text{c}}}$H${}_{36}$ nanocrystal with P${}_{\mathrm{\text{c}}}$ located in its center is completely deformed. In a larger nanocrystal, the spherical surrounding impurity remains and the P–Si bond lengths increase. In Si${}_{86}$P${}_{\mathrm{\text{c}}}$H${}_{70}$, the first sphere is expanded, energies of phosphorous formation in central and subsurface positions differ insignificantly, and the P atom can be located in both the central and subsurface positions. In all nanoparticles, the charges of central P${}_{\mathrm{\text{c}}}$ atoms are negative. The width of the bandgap in undoped nanocrystals is much larger than in bulk silicon and depends on their sizes. The phosphorous introduces the splitting level in the bandgap located closer to the conduction band.