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This paper presents our theoretical investigations on the structural variations of dust acoustic solitary waves (DASWs) in inhomogeneous unmagnetized plasmas. To study the structural variations of DASWs, we have considered collisionless, hot isothermal, and Boltzmannean distribution for electrons-ions with negatively charged dust grains in weakly inhomogeneous plasmas. We have used the reductive perturbation technique (RPT) in the governing equations of plasmas, derived the modified Korteweg-de-Vries (m‑KdV) equation, and obtained the solitary wave solution. We have considered the appropriate stretched coordinates for space and time variables for the inhomogeneous plasma. This paper investigates the effects of dust particles on ion-acoustic solitary waves' propagation in the inhomogeneous plasma model. We have also included the effect of inhomogeneity parameters on the soliton structures.

In the present paper, we will review the methods to produce superposition of entangled coherent state using polarizing beam splitter and Kerr non linearity. These coherent states have many attractive features and can be used in various schemes. Entanglement, refers to the superposition of a multiparticle system and explains a new type of correlations between any two subsystems of the quantum system, which is not existing in the classical physics. The present paper deals with the use of these states in quantum teleportation, entanglement diversion and entanglement swapping schemes. Entanglement diversion and entanglement-swapping refers to a scheme which may entangle those particles which had never interacted before. In the swapping scheme, two pairs of entangled state are taken. One particle from each pair is subjected to a Bell-state-measurement. This would result in projection of the other two outgoing particles in an entangled pair. Quantum Teleportation of two mode and three modes states is also studied with perfect fidelity. Minimum assured fidelity which is defined as the minimum of the fidelity for any unknown quantum information of the states is also discussed. It is also shown how the success rate of teleportation of a superposition of odd and even coherent states can be increased from 50% to almost 100%. The scheme suggested by van Enk and Hirota was modified by Prakash, Chandra, Prakash and Shivani in 2007. We find that an almost teleportation, diversion and swapping is possible by simply separating vacuum state from the even state. The present paper also deals with study of effect of decoherence and noise on these states and the effect of noise on fidelity and minimum assured fidelity. It is also discussed that these schemes can also be applied to the process of entanglement diversion and entanglement swapping. .

The development of efficient metal doped semiconductors for Photovoltaic applications has gained a lot of research attention. In this present paper, pure and silver nanoparticles (AgNPs)-modified TiO2 nanocrystals (NCs) with different amount of AgNPs (say 50, 100, 150, 200, and 250 µL) were achieved and the effects of AgNPs on the TiO2 NCs were explored systematically. The optical, structural and morphological properties were probed using UV-visible spectrophotometer, X-ray diffraction (XRD), and scanning electron microscope (SEM). The results of the optical studies showed a characteristic peak of TiO2 and the redshifting of the peak position was observed by introducing AgNPs. The synergetic effects from AgNPs and TiO2 results to diminished band gap. The XRD result confirmed the formation of a tetragonal anatase TiO2 phase with a decrease in crystallite size with increasing AgNPs content. The SEM images show enhanced nucleation and film growth with presence of shining surface which can be seen to contribute to good photon management by enhancing light scattering. The unadulterated TiO2 and AgNPs-modified TiO2 have spherical morphology and uniform size distribution ranging from 20 to 30 nm. This study established the view that surface modification of TiO2 with AgNPs is a viable approach towards achieving an efficient light photocatalyst.

This paper presents the results of a study of the state of ytterbium atoms in silicon, carried out using the methods of Fourier transform infrared spectroscopy (IR) and Raman spectroscopy (RS). Silicon samples doped with ytterbium impurities were analyzed using FSM-2201 and SENTERRA II Bruker spectrometers. Registration and identification of both crystalline and amorphous phase components in the samples was carried out. The results of the study confirm that doping silicon with ytterbium impurities leads to a decrease in the concentration of optically active oxygen by 30-40%, depending on the concentration of the introduced impurities. It was also found that an increase in the number of defects leads to a broadening of the amorphous zone. It is assumed that similar dependencies exist for the Si-Yb system; however, to the best of our knowledge, similar results have not been reported previously. It is noted that the relative intensity of the three Raman bands in Si-Yb systems in the LTIOS (The light and temperature induced ordered state) state changes, and the relative intensity of Si-Si decreases. This indicates that pendant bonds are mainly formed by the breaking of Si-Si bonds. It was also observed that the light intensity causing this condition is far from that required for laser or solid phase crystallization. Using the Raman spectroscopy method, a structural transformation was discovered, expressed in a densely packed array of nanocrystals with a size of less than 11 lattice parameters. Small clusters were under strong internal stress (up to 3 GPa), which probably prevents the cluster size from increasing beyond the critical value for irreversible crystallization.

The paper investigates the collection coefficient of minority charge carriers in silicon p-i-n photodiodes and the influence of certain technological factors on it. It has been found that the diffusion length of minority charge carriers and the resistivity of the material have a significant effect on the value of the collection coefficient, since the collection area of photogenerated charge carriers increases with increasing these parameters. It was also found that an effective method to increase the collection coefficient of photodiodes is to ensure that the thickness of the high-resistance region of the photodiode is equal to the sum of the diffusion length of minority charge carriers and the width of the space charge region. The effect of the concentration of dopants on the responsivity and collection coefficient is investigated. It was found that, in contrast to the calculated data, in which the collection coefficient increases with decreasing concentrations of phosphorus and boron, in the experimental data, with decreasing concentrations of impurities, the responsivity and, accordingly, the collection coefficient decrease due to a decrease in the degree of heterogenization and, as a result, a decrease in the width of the space charge region and the diffusion length of minority charge carriers.

In this paper, we study a spatially homogeneous and anisotropic Bianchi type-III universe containing cold dark matter and Barrow holographic dark energy within the framework of General Relativity. We assume the cold dark matter and Barrow holographic dark energy to be non-interacting and obtain exact solutions of the Einstein field equations by considering a hybrid expansion law and assuming that the expansion scalar is proportional to the shear scalar. We examine the physical and kinematical properties of the resulting model using parameters such as the Hubble parameter, the anisotropic parameter, the deceleration parameter, the equation of state parameter, the jerk parameter etc. We also examine whether the energy conditions are violated or validated. We find that the Null, Weak, and Dominant energy conditions are fulfilled, while the Strong Energy Condition is violated, which supports the accelerated expansion of the universe. The Statefinder diagnostics have been conducted based on recent cosmological observations. In addition, we reformulated the correspondence between quintessence scalar field and Barrow holographic dark energy model.

This paper presents a numerical study of the linear and non-linear stability of thermosolutal convection within a porous medium saturated by a non-Newtonian binary fluid. The power-law model is utilized for modeling the behavior of the working medium. The given statement implies that the horizontal boundaries experience thermal and solutal flow rates, whereas the vertical walls are impermeable and thermally isolated. The relevant factors that govern the problem being investigated are the Rayleigh number, , the power-law index, , the cavity aspect ratio, , the Lewis number, , and the buoyancy ratio, . An analytical solution is obtained for shallow enclosures ( ) using the parallel flow approximation and a modified form of the Darcy equation. By solving the entire set of governing equations, a numerical investigation of the same phenomenon was conducted. One of the most intriguing discoveries from this research is that it identifies a bi-stability phenomenon, this particular phenomenon signifies the existence of two stable solutions. The results obtained from both methods demonstrate a good level of agreement across a diverse range of these governing parameters.

This paper is devoted to investigate five dimensional homogeneous and isotropic FRW model with varying gravitational and cosmological constant with cosmic time. Exact solution of the Einstein field equations are obtained by using the equation of state p = (γ −1)ρ (gamma law), where γ which is an adiabatic parameter varies continuously as the universe expands. We obtained the solutions for different values of curvature K = 0, 1,−1 by using a(t) = R0(1 + α2t2)n, where α, n and R0 are positive constants. Behaviour of the cosmological parameters are presented for different cases of the models. Physical interpretation of the derived model are presented in details. Interestingly the proposed model justified the current cosmological observations with dark energy.

The paper studies effect of induced magnetic field on laminar convection flow of a viscous electrically conducting incompressible fluid between two parallel porous plates at constant temperature gradient in presence of a uniform inclined magnetic field. An angle (θ) is formed with the vertical line by applying a magnetic field in that direction and field is strong enough to induce another field along the line of flow. Using the proper similarity transformations, the flow equations are converted into ordinary differential equations, which are then numerically solved by using MATLAB's bvp4c solver. Plotting of the graphs allows one to examine the effects of several critical parameters such as Hartmann number, Darcy number, Magnetic Reynolds number, Prandtl number, and Field inclination on velocity field, induced magnetic field, temperature field at the plates. The acquired results demonstrate that the flow system is effectively influenced by the field inclination, the magnetic parameter, and the plate porosity. The rise in field inclination leads to an increase in magnetic drag force.

The paper reports the sharp increase in resistivity and the conductivity change (type) in the single-crystal silicon sample doped with vanadium. The electrical and optical properties of single-crystalline silicon were determined Hall- and four-probe measurements and infrared (IR-) spectroscopy. Relative resistance, charge carrier concentration, mobility, and concentration of optically active oxygen and carbon in the samples were determined layer-by-layer. It is shown that in silicon samples doped with vanadium the concentration of optically active oxygen atoms tends to reduce.

In this paper, a comparative study on MHD forced convective flow for heat transfer efficiency of different nanofluids with water (H2O) as base fluid has been carried out. Here, in this study flow through vertical rectangular has been considered in presence of strong magnetic field. In this laminar flow we consider duct walls as electrically non-conducting where the transverse magnetic field acting normally on the duct walls. Joule heat and the viscous dissipation effects are included in the energy equation and furthermore the walls of the duct are kept at constant temperature. An explicit finite difference method has been adopted with fine grid in the control volume for solving the governing equations of this MHD nanofluid flow. Computational processes are carried out using MATLAB code. In this present work we have plotted the flow fields velocity, induced magnetic field, and temperature for various values of MHD flow parameters graphically by varing thermal Grashof number (Gr), Hartmann number (Ha), Reynold number (Re), Eckert number (Ec), Prandtl number (Pr), magnetic Reynold number (Rm), and nanoparticle volume fraction (ϕ) respectively.

This paper investigates and examines a wide range of findings related to the description of holographic Ricci dark energy (HRDE) with the bulk viscosity within Universe's late-time accelerated expansion in the framework of an anisotropic Bianchi type-III cosmological model with pressure-less matter content in the Brans-Dicke theory of gravity. We are using the relationship between the metric potentials to obtain a precise conclusion to the field equations, resulting in a rapid expansion. Several major cosmological parameters, including Hubble, deceleration, matter energy density, Ricci dark energy density (RDE), and Equation of state (EoS), are used to investigate the physical behavior of our dark energy model. We detected some of the viscosity of the holographic Ricci dark energy model using current cosmological observations. We describe how the model's physical and geometric properties are compatible with recent compilations.

The purpose of this paper is to construct anisotropic and spatially homogeneous Bianchi type-VI0 Kaniadakis holographic dark energy (KHDE) model in general relativity. For this purpose, we consider Hubble horizons as the IR cutoff. To obtain a deterministic solution of the field equations of the model we assume a relationship between the metric potentials which leads to an exponential solution and accelerated expansion. In order to investigate the physical behavior of our dark energy model, we obtain some important cosmological parameters like Hubble, deceleration, equation of state and statefinder as well as ωkhde-ω'khde, r-s and r-q planes. We also included the stability analysis for the dark energy model through the squared speed of sound. It is observed that the equation of state parameter shows ΛCDM model at late times. Also, the squared speed of sound gives the stability of KHDE model at initial epoch and model is unstable at late times. Statefinder diagnostic and deceleration parameters exhibit a smooth transition of the universe from decelerating phase to current accelerated expansion of the universe and also correspond to the ΛCDM model at late times. All these cosmological parameters support recent observational data.

In this paper, the influence of gravitational modulation on weakly nonlinear biothermal convection in a porous rotating layer is investigated. We consider a layer of porous medium saturated with Newtonian fluid, containing gyrotactic microorganisms, and subject to gravitational modulation, rotation, and internal heating. To analyze linear stability, it is sufficient to represent disturbances in the form of normal modes, while nonlinear analysis includes a truncated Fourier series containing a harmonic of the nonlinear interaction. A six-dimensional nonlinear Lorentz-type model is constructed, exhibiting both reflection symmetry and dissipation. We determined heat and mass transfer using a weakly nonlinear theory based on the representation of a truncated Fourier series. Additionally, the behavior of nonstationary Nusselt and Sherwood numbers was investigated by numerically solving finite amplitude equations. Applying the expansion of regular perturbations in a small parameter to a six-dimensional model of Lorentz equations with periodic coefficients, we obtained the Ginzburg-Landau (GL) equation. This equation describes the evolution of the finite amplitude of the onset of convection. The amplitude of convection in the unmodulated case is determined analytically and serves as a standard for comparison. The study examines the effect of various parameters on the system, including the Vadasz number, modified Rayleigh-Darcy number, Taylor number, cell eccentricity, and modulation parameters such as amplitude and frequency. By varying these parameters, in different cases, we analyzed heat and mass transfer, quantitatively expressed by the Nusselt and Sherwood numbers. It has been established that the modulation amplitude has a significant effect on the enhancement of heat and mass transfer, while the modulation frequency has a decreasing effect.

In this paper, we investigate the effects of anisotropic parameters, topological defects, and magnetic flux on the dissociation energy of bottomonium in an anisotropic quark-gluon plasma. We use the three-dimensional Schrödinger equation and derive the energy eigenvalues. Our findings show that the dissociation energy decreases with increasing temperature, but there is a slight shift towards higher values when the magnetic flux is increased. Furthermore, the inclusion of topological defects causes further shifts in the dissociation energy at high temperatures. Additionally, we analyze the impact of anisotropic medium on dissociation energy, both with and without considering topological defects. We observe that including topological defects results in higher values for the dissociation energy across all temperatures, while ignoring them leads to lower values at all temperatures studied. Moreover, we consider the baryonic chemical potential and find that its effect on dissociation is negligible compared to temperature variations. These findings provide valuable insights into the behavior of heavy quarkonium systems under different physical conditions and contribute to our understanding of topological effects in anisotropic media.

This paper presents the impact of temperature variations and alterations in transistor channel dimensions on CMOS (Complementary Metal-Oxide-Semiconductor) circuit technology. To facilitate this investigation, we first identified critical parameters characterizing the device's performance, which could exhibit susceptibility to these influences. The analysis encompassed critical metrics such as the transfer characteristic, drain current, logic levels, inflection points, and truncation points. These parameters enabled us to validate the results obtained from the PSPICE simulator, which demonstrated unequivocal effectiveness. Notably, our simulation results unveiled significant effects resulting from a wide temperature range spanning from -100°C to 270°C, offering valuable in-sights into thermal-induced failures. Additionally, the influence of channel dimension changes on factors like drain current and transfer characteristics, as well as temporal parameters including signal propagation delay and rise and fall times, were meticulously examined and appreciated.

In this paper, we have presented our investigation on the characteristics of nonlinear dust acoustic waves (DAWs) propagating in an inhomogeneous collisionless magnetized dusty plasma (MDP). In this problem, we have considered a collisionless plasma consisting of nonthermal ions, non-extensive electrons and negatively charged dust grains. Using the reductive perturbation theory (RPT) we have derived the modified Zakharov-Kuznetsov (m-ZK) equation. The solution of m-ZK equation indicates the nonlinear characteristics of the DASWs in plasma. Our investigation also predicts how the amplitudes of nonlinear DASWs are significantly modified due to the influence of magnetic field, non-extensive electrons and inhomogeneity parameters in plasma. The results obtained in this investigation may be useful for understanding the propagation characteristics and modification of structures of nonlinear waves in both laboratory and astrophysical plasmas.

In this paper the content of heavy metals at the territory of Pyatihatki settlement, where the National Scientific Center Kharkiv Institute of Physics & Technology (NSC KIPT) is located. The nuclear-physical methods were used to determine the content of chemical elements in the soil samples taken in 30 points at the territory of Pyatihatki settlement in 2011-2021. The elemental analysis was carried out on the analytical nuclear-physical complex "Sokol". The methods, based on registration of characteristic X-ray radiation of atoms and g-radiation of nuclei excited by accelerated protons, were used. After the measurements completion, the data arrays on the content of 15 chemical elements (N, Na, S, Cl, K, Ca, Ti, Mn, Fe, Cu, Zn, Zr, Br, Sr, Pb) in the soil samples were obtained. The data arrays processing was carried out using the EPA (Environmental Protection Agency) PMF v3.0.2.2.2 software based on the application of the PMF (Positive matrix factorisation) algorithm. ArcView 3.2a was chosen as the basic software product for the analysis of spatial distribution of the major polluting chemical elements. As a result of the performed work, the pollution sources, which have an impact on the territory near the NSC KIPT, have been identified. The source of the soil pollution is the autostrades, among which the road around the city Kharkiv stands out, where an increase in the content of Pb, Sr, Zr, Cr and Cu was detected. A source of chromium contamination, located presumably to the north-east of Pyatihatki settlement, was identified. The analyses of the obtained data showed that the PMF method allows to identify the factors that affect the soil contamination, and to determine the presumptive sources of pollution with the help of wind rose.

The paper discusses the properties of the nonlinear thermodiffusion equation corresponding to the heat transfer processes occurring with a finite velocity in gas from a high intensity source. In the previous papers A. J. Janavičius proposed the nonlinear diffusion equation which provided a more exact description of impurities diffusion by fast moving vacancies generated by X-rays in Si crystals. This is similar to the heat transfer in gas with constant pressure by molecules carrying a greater average kinetic energy based on the nonlinear thermodiffusion of gas molecules from hot regions to the coldest ones with a finite velocity by random Brownian motions. Heat transfer in gas must be compatible with the Maxwell distribution function. Heat transfer in gas described by using nonlinear thermodiffusion equation with heat transfer coefficients directly proportional to temperature . The solution of the thermodiffusion equation in gas was obtained by using similarity variables. The equation is solved by separating the linear part of the equation that coincides with Fick's second law. The obtained results coincide with Ya.B. Zeldovich’s previously published solutions of nonlinear equations by changing the respective coefficients.

The study was performed on alloys with a carbon content of 0.37-0.57% (wt.), silicon 0.23-0.29% (wt.), manganese 0.7‑0.86% (wt.), the rest– iron. To determine the phase composition of alloys used microstructural, microanalysis and X-ray analysis. In addition, the physical characteristics of the alloys studied in this paper were determined, such as alloy chemical dependence of extension and contraction ratio, impact toughness and hardness. The results obtained in this paper showed that the iron-based alloy with the content of carbon of 0.57 % (wt.), silicon of 0.28 % (wt.) and manganese of 0.86 % (wt.)) had the superior microstructure and physical properties. It was determined that after a number of crystallization and phase transformation the alloy phase structure includes two phases: a-iron and cement magnesium dopingFe2.7Mn0,3C. For the first time using the method quasi-chemistry received an expression of the free energy of a solid solution α-iron alloyed with silicon and magnesium, and determined the solubility limit of carbon, manganese and silicon. In δ-iron may dissolve to 0.09% (wt.) carbon, manganese up to 3.5% (wt.), silicon – 0.25% (wt.). The maximum content in α-iron can reach: carbon – 0.017% (wt.), manganese – 21% (wt.), silicon – 1.3% (wt.).

Relaxation of the electron energy and momentum densities is investigated in spatially uniform states of completely ionized plasma in the presence of small constant and spatially homogeneous external electric field. The plasma is considered in a generalized Lorentz model which contrary to standard one assumes that ions form an equilibrium system. Following to Lorentz it is neglected by electron-electron and ion-ion interactions. The investigation is based on linear kinetic equation obtained by us early from the Landau kinetic equation. Therefore long-range electron-ion Coulomb interaction is consequentially described. The research of the model is based on spectral theory of the collision integral operator. This operator is symmetric and positively defined one. Its eigenvectors are chosen in the form of symmetric irreducible tensors which describe kinetic modes of the system. The corresponding eigenvalues are relaxation coefficients and define the relaxation times of the system. It is established that scalar and vector eigenfunctions describe evolution of electron energy and momentum densities (vector and scalar system modes). By this way in the present paper exact close set of equations for the densities valid for all times is obtained. Further, it is assumed that their relaxation times are much more than relaxation times of all other modes. In this case there exists a characteristic time such that at corresponding larger times the evolution of the system is reduced described by asymptotic values of the densities. At the reduced description electron distribution function depends on time only through asymptotic densities and they satisfy a closed set of equations. In our previous paper this result was proved in the absence of an external electric field and exact nonequilibrium distribution function was found. Here it is proved that this reduced description takes also place for small homogeneous external electric field. This can be considered as a justification of the Bogolyubov idea of the functional hypothesis for the relaxation processes in the plasma. The proof is done in the first approximation of the perturbation theory in the field. However, its idea is true in all orders in the field. Electron mobility in the plasma, its conductivity and phenomenon of equilibrium temperature difference of electrons and ions are discussed in exact theory and approximately analyzed. With this end in view, following our previous paper, approximate solution of the spectral problem is discussed by the method of truncated expansion of the eigenfunctions in series of the Sonine polynomials. In one-polynomial approximation it is shown that nonequilibrium electron distribution function at the end of relaxation processes can be approximated by the Maxwell distribution function. This result is a justification of Lorentz–Landau assumption in their theory of nonequilibrium processes in plasma. The temperature and velocity relaxation coefficients were calculated by us early in one- and two-polynomial approximation.

This paper presents a study of operating characteristics of steel 40X10C2M after treatment it of high-energy plasma pulses. The steel is used to manufacture the elements of ships' power plants. For pulsed plasma treatment of steel samples, we used an electrothermal plasma accelerator (ETPA). A high-current pulsed high-pressure arc discharge was initiated in a restricted dielectric chamber of ETPA. The discharge duration was 1.4 ms, the maximum current reached the value of 5 kA, the discharge voltage was up to 5 kV. We investigated the microhardness and microstructure of the processed (modified) layer and determined the optimal parameters of steel processing that provide the best characteristics of the modified layer when the microhardness increases by ≈ 5 times. Microhardness maxima were discovered in the depth of the modified layer. The paper studies the possibilities of controlling the maxima localization to form the desired performance characteristics of the treated layer. Mathematical modeling of rapid pulsed heating of the steel surface layer is performed within the framework of the two-phase "melt-solid" model, taking into account the dynamics of the thermodynamic characteristics of steel. For this purpose, we used the classical equation of thermal conductivity with varying steel parameters: density, heat capacity, and coefficient of thermal conductivity during the transition of a substance from the liquid to the solid phase. Within the chosen mathematical model, numerical calculations of the rapidly pulsed heating phenomenon of the steel surface were performed, taking into account melting and solidification in the Comsol Multiphysics package using the finite element method. The numerical simulation results are in good agreement with the experimental distribution of the microhardness of the treated steel layer deep into the sample.

This paper is devoted to the studies of the opportunities for the intensification of the particle diffusion in the periodic structures, for example, the crystals that are exposed to the action of the time-periodic fields of a different nature. These can be acoustic or electromagnetic fields. The trivial one-dimensional model of the motion of the particles in the potential lattice field under the thermal equilibrium has been used. The paper studies the interaction of rectangular fields with the frequencies less than 0.01 ω0, where ω0 is the frequency of natural small vibrations of the particles in the systems with the low dissipation. The selected friction coefficient in dimensionless units is equal to γ'=0.03. The amplitude dependence of the intensification of the diffusion D under the action of the fields of a different frequency has been studied. It was shown that the diffusion coefficient can be increased by several orders of magnitude by applying the field of an appropriate amplitude and frequency. A maximum diffusion intensification is attained at ω→0. A maximum attained value of the diffusion coefficient at the periodic force corresponds to the case of the action of the constant force. However, at low frequencies a maximum intensification is only possible in the narrow range of field amplitudes F'oc γ'. A further increase in the field amplitude results in a decrease of the diffusion coefficient and it attains the value of the coefficient of the particle diffusion in the viscous medium Dvis=k'T'/γ', where k' is the Boltzmann coefficient and T' is the temperature. An increase in the frequency of the external force results in the extension of the range of forces at which D>Dvis, however the value of the diffusion intensification is decreased. It was shown that the exceed of a certain threshold value of the amplitude of the external field results in the gain of the diffusion coefficient at least by the value of η=(k'T'eε/k'T')/(γ"D0, where ε is the value of the energy barrier during the passage of the particle from one cell of the one-dimensional lattice to another. The obtained data open prospects for the development of new technologies to exercise control over diffusion processes. It is of great importance for the production of nanomaterials with the specified structure, creation of the surface nanostructures, etc.

Titanium is currently familiar for its light weight, high strength, and non-reactive nature over all the metals. Titanium metal matrix composites (TMCs) are very popular in the field of aerospace, automotive, defense, and biomedical because of their high specific strength, light weight, and biocompatibility nature. Some of the extensively used fabrication methods like powder metallurgy (PM), additive manufacturing (AM), and spark plasma sintering (SPS) have been reviewed here with some of the properties of TMCs. By varying various types of reinforcements, it is possible to achieve the required properties as per industrial and modern applications in TMC. This study also includes the consequence of sintering temperature on properties of TMCs like physical, mechanical, and structural. Titanium alloys are showing good mechanical and biomedical properties when reinforced with carbon fibers, borides, ceramics, and plenty of other materials as continuous fiber or discontinuous particulates and whiskers. In this paper, the applications of TMCs in aerospace, automobile, biomedical, and defense have been narrated. Besides all these favorable properties and applications, TMCs can’t be used extensively in the said applications because of their high cost and difficulty in machining, that discussed in this paper over various challenges of TMCs. The cost reduction can be done by making Ti - super alloys. In addition, there is a necessity for an effective cooling system during the machining of TMCs to enhance machinability and some of the effective methods which may enhance the machinability of TMCs were also discussed.

In this work the study is performed for the specimens of Fe-B-C alloys with boron content of 0.005–7.0 wt. % and carbon content of 0.4–6.67 wt. %, the rest is iron. According to the findings of microstructure analysis, XRD and differential thermal analyses, the primary phases and the temperatures of their formation are determined. Depending on boron content (in the range of 1.5–8.80 wt. %) and carbon content (0.5–6.67 wt. %) in the Fe-B-C alloys, the primary phases in the process of crystallization are γ-Fe, boron cementite Fe3(CB) and boride Fe2В. The outcomes of the experiment carried out in this work determine the phase composition and phase transformations occurring in the alloys and the liquidus surface is constructed. The findings show that the liquidus temperature for Fe-B-C system alloys is low compared to binary Fe-B and Fe-C alloys. At the liquidus surface of the Fe-B-C alloys, there is a point at boron content of 2.9 wt. % and carbon content of 1.3 wt. % with the lowest temperature of 1375 K and it is the point of intersection of monovariant eutectics. This fact is in a good agreement with the results of other authors. The microstructure of alloys located at the curves of monovariant eutectics is represented by the γ–Fe+Fe2B and γ–Fe+Fe3(CB) eutectics and the primary crystals of Fe2B iron boride in the shell of Fe3(BC) boron cementite. In this paper it is shown experimentally the existence of a quasi-binary section and the coordinates of the peritectic point are fixed: the boron content is 5.0 wt. %, carbon content is 3.0 wt. % and the temperature is 1515 K. The free energy of the Fe-B-C melt is calculated for the first time by the quasi-chemical method and the surface of thermodynamic stability of the Fe-B-C melt is plotted, depending on temperature and boron and carbon content in the alloy. The results obtained in the paper show that in order to obtain a homogeneous Fe-B-C melt, which does not contain any microheterogeneous structure in the form of short-order microregions, it is necessary to perform the overheating more than to 180 K for the region where the primary phase is iron, and no less than to 200 K for the regions with boron cementite and boride.

The paper presents the results of the study of the models of convective instability near its threshold of thin layers of liquid and gas bounded by poorly conducting walls. These models single out one spatial scale of interaction, leaving the possibility for the evolution of the system to choose the symmetry character. This is due to the fact that the conditions for the realization of the modes of convective instability near the threshold are chosen. All spatial perturbations of the same spatial scale, but of different orientations, interact with each other. It turned out that the presence of minima of the interaction potential of the Proctor-Sivashinsky equation modes, the absolute value of the wave number vectors of which is unchanged, determines the choice of symmetry and, accordingly, the characteristics of the spatial structure. In the case of a more realistic model of convection described by the Proctor-Sivashinsky equation, it was possible to observe both the first-order phase transition and the second-order phase transition and detect the form of the state function, which is responsible for the topology of the resulting convective structures: metastable rolls and stable square cells. In this paper, it is shown that the nature of the structural-phase transition in a liquid when taking into account the dependence of viscosity on temperature in the Proctor-Sivashinsky model is similar to the case of the absence of such a dependence. The transition time turns out to be the same, despite the fact that a different structure is formed - hexagonal convective cells. As in the Swift-Hohenberg model, a hard mode for the formation of hexagonal cells in a gas medium is possible only for a sufficiently noticeable dependence of its viscosity on temperature. The phase transition times are inversely proportional to the difference in the values of this function for two consecutive states. A similar description of phase transitions did not use phenomenological approaches and various speculative considerations, which allows for a closer look at the nature of transients.

In the paper we obtained the expression of cementite free energy and determined the solubility of manganese and silicon in Fe3C cementite depending on the temperature. Investigation was carried out for alloys with carbon content of 0.55-0.60 % (wt.), silicon content of 0.95-1.0 % (wt.), manganese content of 0.8-0.9% (wt.), the rest was iron. The smelting of Fe-Mn-Si-C system alloys was carried out in the alundum crucible furnace in argon atmosphere. The cooling rate of alloys after casting was 10 K/s. Microstructure analysis along with X-ray diffraction analysis was used to determine the structural state of the alloys. In addition, the physical characteristics of the alloys studied in this paper were determined, such as alloy chemical dependence of ultimate strength, extension and contraction ratio, impact toughness and hardness. The results obtained in this paper showed that the iron-based alloy with the content of carbon of 0.57 % (wt.), silicon of 0.97 % (wt.) and manganese of 0.85 % (wt.)) had the superior microstructure and physical properties. The microstructure of alloys studied in the paper is represented by pearlite, which makes up to 95 % of the volume. In the alloys we revealed the highly dispersed inclusions of Fe2.7Mn0.3C, Fe0.25Mn1.4C0.6 and Fe9SiC0.4 carbides, whose volume ratio was up to 1.5 %, the rest was ferrite. As it is known, the structural constituent of pearlite is cementite. The cementite has a significant effect on the physical properties of alloys. Application of quasi-chemical method enables to calculate the free energy of silicon and manganese doped with cementite and to determine the temperature dependence of silicon and manganese content in cementite. It is ascertained that there is a slight increase of carbon content in cementite (up to 28.79 % (atoms). Manganese can replace up to 12 % of iron atoms, and silicon can replace up to 4.5 % of iron atoms, depending on temperature. The calculated data obtained in this paper are in good agreement with those found experimentally by other authors.

Theoretical physics has attained stage when new methodological approaches should be taken into considerations. In particular they should introduce larger discipline in theoretical speculations. In this paper one introduces concept of cognition manifold as methodological framework for development of description of reality by theoretical physics with the aid of theoretical speculations. One assumes that this is a way for constructing fundamental and universal physical theories. The cognition manifold is composed of basis which represents models of our space as a medium and bres representing models of processes in corresponding space. Models are based on accessible experimental results and also on new assumptions and hypotheses obtained by theoretical speculations. In order to maintain dyscipline in these speculations one considers status of assumptions and theories spanned on cognition manifold as a function defined on elements of fibres. One accentuates importance of selforganizing reasoning as more appropriate for recognition of reality in comparison with precise pure mathematical proof. One considers also proof with respect to reality. This paper is considered as an attempt to formalization of cognition process what is manifested by three main components: cognition manifold, status of assumptions and theories and concept of selforganizing reasoning.

Investigation was carried out for Fe-B-C alloys with carbon content of 0.0001–0.01 % (wt.) and boron content of 0.0001–0.01 % (wt.), the rest is iron. To determine the structural state of alloys we use the microstructure analysis, X-ray microanalysis and X-ray structure analysis. The level of microstraines, dislocation density and the coercive force of ferrite is determined, and it is shown that structure imperfection grows with boron content increase in the alloy. The obtained results enable to suggest that boron atoms in a solid solution of α-iron occupy substitutional-interstitial positions depending on boron content. In the paper it is shown experimentally, that at room temperature solubility limit of boron and carbon in the ferrite is 0.00012 % (wt.) and 0.006 % (wt.). When boron and carbon content increases further, the following phases are formed: Fe2B, Fe3(CB) and Fe23(CB)6. In this paper by means of quasi-chemical method we obtain for the first time temperature dependence of the free energy for α-iron solid solution, as well as solubility limit of carbon and boron. Maximum mass fraction of carbon may be up to 0.016 % (wt.), and maximum boron mass fraction – up to 0.00025 % (wt.). At room temperature the boron solubility limit in ferrite is 0.0001 % (wt.), and carbon one is 0.004 % (wt.). The calculated numerical values of the solubility of boron and carbon in ferrite of the Fe-B-C system alloys are less than that of the experimental results. This can be explained by the fact that boron atoms interact more actively with structure imperfections than carbon atoms. At high temperatures the solubility of carbon and boron in given phase increases.

Three-nucleon systems are essential for the investigation of many-body forces in nuclear physics. Well-grounded parametrization of their vertex functions with further application for the calculation of cross-sections in nonlocal QED approach provides the ground for investigation of the variety of multi-particle systems. In present paper we describe the process of parametrization of two-particle photo-breakup amplitudes of three-nucleon systems (3H, 3He). We provide the general description of the wave function construction for three-nucleon systems as well as the parametrization of their vertex functions accounting two- and three-nucleon interactions based on meson exchange current formalism. In our calculations we account first and second order one-pion exchange terms and the term related to the exchange of ω and ρ mesons. The three-nucleon interaction potential is given as a sum of attraction (two-pion exchange) term and appropriate repulsive part. Based on the variational ”Urbana + Model VII” amplitudes we provide the results for energy dependence of differential cross-section of 3He(γ, p)d reaction at proton angle θ = 90◦ from the threshold up to Eγ = 40 MeV and compare theoretical predictions with the available experimental data. The investigation is also provided for angular cross-section distributions at high photon energies (Eγ = 305 ± 5 MeV; 365 ± 5 MeV; 450 ± 10 MeV and 675 ± 50 MeV). Correct description of 3H, 3He photo-disintegration processes in a unified approach based on the gauge nature of the electromagnetic field implies application of this model for other multi-particle systems.

This paper presents the results of studies of the effect of isothermal annealing at temperatures T = 673¸1473 K in the time interval 5¸60 minutes on the electrical properties of silicon, simultaneously alloyed with nickel and copper. Samples of n-Si were obtained on the basis of the starting material - single-crystal silicon, grown by the Czochralski method with the initial resistivity r = 0.3 Ohm×cm. Diffusion was carried out at a temperature of 1523 K for 2 hours. After that, the samples were cooled at a rate of 0.1 K/s. The morphological parameters of impurity nickel and copper atom clusters formed in the bulk of silicon were measured by electron probe microanalysis on a modern Superprobe JXA-8800R setup. As it turned out, in the volume of n-Si samples, clusters of impurity atoms with different geometric shapes are formed, the sizes of which reach up to 500 nm. The electrical properties of the samples were studied by the Hall effect method using an Ecopia HMS-7000 instrument. It was revealed that under the influence of thermal annealing (TA) at T≥1273 K, impurity clusters decompose, which leads to an increase in the resistivity of n‑Si samples. After exposure to TA at Т=1273 K for 15 minutes, the density of impurity nanoaccumulations of acicular and lenticular shapes sharply decreases in the sample volume. Under the influence of TA at T = 1473 K for 10 minutes in the volume of the sample, the decay of impurity nanoclusters with a spherical shape is observed. Also presented are the results of changes in the density of impurity clusters, as well as structural analyzes of the samples before and after exposure to thermal annealing.

In this paper, we study spatially homogeneous and anisotropic Bianchi type-I space-time filled with perfect fluid within the framework of f(R,T) theory of gravity for the functional form f(R,T)=R+2f(T) with f(T)=αT+βT2, where α and β are constants. Exact solutions of the gravitational field equations are obtained by assuming the average scale factor to obey a hybrid expansion law and some cosmological parameters of the model are derived. Two special cases, leading to the power-law expansion and the exponential expansion, are also considered. We investigate the physical and geometrical properties of the models by studying the evolution graphs of some relevant cosmological parameters such as the Hubble parameter (H), the deceleration parameter ( q) etc.

This paper investigates the impact of gravity modulation on weakly nonlinear magnetoconvection in a nanofluid layer that is nonuniformly rotating. The fundamental equations are obtained for the Cartesian approximation of the Couette flow using the Boussinesq approximation and gravitational modulation. The weakly nonlinear regime is analyzed using the method of perturbations with respect to the small supercritical parameter of the Rayleigh number, considering the effects of Brownian motion and thermophoresis in the nanofluid layer. Heat and mass transfer are evaluated in terms of finite amplitudes and calculated from the Nusselt numbers for the fluid and the volume concentration of nanoparticles. The findings demonstrate that gravitational modulation, nonuniform rotation, and differences in the volume concentration of nanoparticles at the layer boundaries can effectively control heat and mass transfer. Additionally, the negative rotation profile has a destabilizing effect. The study shows that the modulated system conveys more heat and mass than the unmodulated system.

In this paper, we analysed the five-dimensional plane-symmetric cosmological model containing perfect fluid in the context of f(R, T) gravity. Field equations have solved for two class of f(R, T) gravity i.e., f(R, T) = R + f(T) and f(R, T) = f1(R)f2(T) with the inclusion of cosmological constant Λ and quadratic equation of state parameters in the form p = αρ2 − ρ, where α is a constant and strictly α≠ 0. In order to derive the exact solutions, we utilize volumetric power law and exponential law of expansion. The physical and geometrical aspects of model have discussed.

The paper studies the properties of surface and near-surface region of a single crystalline silicon sample doped with atoms of Ga (AIII) and Sb (BV). n-type single-crystal Si wafers were chosen as substrates, and samples were size of 8×10×0.5 mm3. For diffusion into silicon, Ga and Sb impurities were used with a purity of 99.999 and 99.998, respectively. The authors propose that a new heterostructure might form in the near-surface region of silicon that could be engineered by applying a relatively cheap diffusion method. The experimental and analysis results show that the composition and absorption spectrum of silicon start manifest certain changes, and can be used in the future as a functional material for solar cells. The result showed that randomly located islands with an average diameter of 1–15 µm are formed on the substrate surface. X-ray diffraction analysis was carried out using a Rigaku diffractometer to study the crystallographic parameters of islands formed with the participation of Ga and Sb atoms on the silicon surface. The energy spectrum was studied on Nanofinder High End Raman spectrometer (LOTIS TII) in order to determine the presence of complexes of Ga and Sb atoms within islands formed as a result of diffusion. The optical emission spectra in the new structure were studied using a Lambda 950 spectrophotometer. The measurements were carried out at room temperature, i.e., at 300°K. Having studied the results of X-ray analysis, Raman spectroscopy, and optical spectroscopy, the authors have revealed that Ga and Sb atoms form new Si0.44(GaSb)0.56 and Si0.75(GaSb)0.25-type binary compounds on Si surface.

The paper examines the properties of CdS thin film, which is used for window material of solar cells and optical devices. The cadmium sulfide (CdS) thin film was prepared by sol-gel method on glass and ITO substrate. Prepared thin film dried in a vacuum oven at 70℃. Thin film and powder of CdS characterized for structural, optical, and electrical properties by X-ray Diffractometer (XRD), UV-Visible spectrometer, and Keithley spectrometer. The average crystallite sizes, microstrain, and dislocation density of the samples were calculated by the Debye Scherrer formula. The optical band gap of CdS calculated by the Tauc-plot method and obtained 2.40 and 2.41eV for powder and film. The absorption wavelength of CdS is suddenly decreased near 280nm and becomes flat in the higher wavelength region. The FTIR spectrometer is used to identification of unknown materials and bond formation. The bond formation, imperfections, and impurities were observed by the PL spectrometer. Keithley spectrometer is used for I-V characteristics and calculates electrical resistivity by Ohms law.

The paper determines the technological regimes for obtaining GexSi1-x alloys by introducing germanium atoms into single-crystal silicon by the diffusion method. From the results of the study, it was found that the fundamental parameters of the formed GexSi1-x alloys differ from the fundamental parameters of the original silicon, in particular, the energy values of the silicon band gap change. Elemental analysis of the surface of the samples showed that the concentration of silicon (in atomic percent) was ~70.66%, germanium ~29.36%. It was assumed that on the silicon surface and in the front part, a thin layer of an alloy of a compound with a composition of approximately Ge0.3Si0.7 (0.5÷2 μm) would be formed. Analysis of the spectra (p shows that the spectrum contains peaks ~303 cm-1 and ~406 cm-1, corresponding to the Ge-Ge and Si-Ge bonds, respectively. It was also shown that GexSi1-x binary compounds are a new material for modern electronics, the possibility of creating properties on their basis in electronics was shown. It is proposed on their basis to create devices with new functionality and highly efficient solar cells.

Heat transmission by ordinary fluids such as pure water, oil, and ethylene glycol is inefficient due to their low viscosity. To boost the efficiency of conventional fluids, very small percent of nanoparticles are added to the base fluids to prepare nanofluid. The impact of changing in viscosity can be used to investigate the rheological properties of nanofluids. In this paper, (CoFe2O4)/engine oil based nanofluids were prepared using two steps standard methodology. In first step, CoFe2O4 (CF) were synthesized using the sol-gel wet chemical process. The crystalline structure and morphology were confirmed using X-Ray diffraction analysis (XRD) and scanning electron microscopy (SEM), respectively. In second step, the standard procedure was adapted by taking several solid volume fractions of CF as Ø = 0, 0.25, 0.50, 0.75, and 1.0 %. Such percent of concentrations were dispersed in appropriate volume of engine oil using the ultrasonication for 5 h. After date, the viscosity of prepared five different nanofluids were determined at temperatures ranging from 40 to 80 °C. According to the findings, the viscosity of nanofluids (µnf) decreased as temperature increased while increased when the volume percentage of nanofluids Ø raised. Furthermore, total 25 experimental observations were considered to predict viscosity using an artificial neural network (ANN) and response surface methodology (RSM). The algorithm for building the ideal ANN architecture has been recommended in order to predict the fluid velocity of the CF/SAE-50 oil based nanofluid using MATLAB software. In order to determine the correctness of the predicted model, the mean square error (MSE) was calculated 0.0136.

The paper is concerned with the study of silicon samples doped with gallium (Ga) and antimony (Sb) atoms. In particular, the elemental analysis, SEM imaging, and Raman spectrometry analysis of the samples are presented. The elemental analysis revealed that the relative concentrations of Ga (0.4) were almost equal to those of Sb (0.39) and both were formed on the surface of Si. The SEM imaging showed that GaSb microsized islands (diameter of 1 to 15 microns) and a density of ~106 cm-2 were being formed on the surface of Si in the course of the process of diffusion doping. Raman spectral analysis showed that a semiconductor with GaSb molecules self-assemble on Si surface.

The paper presents the results of a study of the charge and energy characteristics of multiply charged ions excited on the surface of a single-element and hydrogen-containing multi-component element targets under the influence of laser radiation with a power density (q=108-1012 W/cm2). It has been experimentally shown that, for all used values of q laser radiation, laser-induced plasma from gas-containing targets is characterized by a lower relative yield (dN/dE) of multi-charged ions with a charge number of Z>+3, compared to the plasma produced on the surface of the single element target. Moreover, the tendency to reduce dN/dE of multi-charged ions of the multi-element target, in comparison with the relative yield of ions from the plasma of the single-element target, is more significant and it depends on the charge of the excited ions. The increase in the charge and energy state, duration, and yield of ions of the heavy component, which occurs with an increase in the content of the light component in the target, has been established. This is explained by a decrease in the efficiency of recombination processes caused by an increase in the expansion velocity of a plasma plume due to a decrease in its average mass.

The paper examines heat and mass transfer in MHD convective flow across a vertical porous plate in presence of radiation, heat sink, and dissipation of heat. A strong magnetic field is applied perpendicular to the plate and directed into the fluid area. The governing non-dimensional equations are solved using MATLAB built-in bvp4c solver technique. With the use of mathematical software, the findings are computed, and the effect of the various non-dimensional parameters entering into the problem on the velocity, temperature and concentration profiles are displayed in graphical formats. It has been noted that the application of the magnetic field slows down fluid velocity. Additionally, both the thermal radiation effect and the Prandtl number are fully applicable to the fluid temperature. It is significant to notice that the heat sink dramatically reduces fluid temperature and fluid velocity. The current work is utilized in many real life applications, such as chemical engineering, industrial processes, a system may contain multiple components, each of whose concentrations varies from one point to the next in a number of different circumstances.

In this paper we study the structural condition and thermodynamic functions of a melt of the Pb-Sb. The investigations were performed for alloys with an antimony content of 5.0-20.0% (wt.), the rest is lead. To determine the structural condition of alloys we use microstructure analysis, differential thermal and X-ray structural analyses. The phase composition of alloys was determined in relation to the temperature of the liquid heating above the liquidus curve and to the cooling rate. With accounting for the first degree approximation of high-temperature expansion of the thermodynamic potential in expression for the Gibbs energy of a melt of the binary Pb-Sb alloy we find the curve of thermodynamic stability of the liquid depending on the antimony content in alloy. This approach enables to give the most complete description of the alloys’ melt from the thermodynamic point of view and to determine a thermodynamic stability curve, above which there are no microcomplexes in the phase. The results of the calculations obtained in this paper are in good agreement with the experimental data.

The energy of disruption generated runaway electrons can reach as high as tens of megaelectronvolt and they can cause a serious damage of plasma-facing-component surfaces in large tokamaks like International Thermonuclear Experimental Reactor (ITER). The synchrotron radiation diagnostic allows a direct observation of such runaway electrons and an analysis of their parameters and promotes the safety operation of present day large tokamaks and future ITER. Only this diagnostic will be applied in ITER. In the paper detail analysis of the synchrotron radiation spectra of runaway electrons for the recent Experimental Advanced Superconducting Tokamak (EAST, Institute of Plasma Physics of Chinese Academy of Sciences) experiment parameters has been presented. The calculations are carried out on the base of precise expression for synchrotron radiation spectral density. They make more precise spectra analysis of the previous paper by Zhou R.J., Pankratov I.M., Hu L.Q., et al. (Physics of Plasmas, 2014, Vol. 21, No. 6, 063302). Obtained results are important for correct interpretation of runaway EAST experiments and runaway experiments in other tokamaks.

This paper demonstrates the synthesis of NixCd1-xS (x=0.8,0.6,0.4,0.2) nanoparticles by microwave-assisted chemical precipitation method. The prepared samples were characterized by XRD, EDAX, SEM, UV-VIS, and PL spectroscopy. The energy-dispersive x-ray analysis confirms the existence of Nickel, Cadmium and Sulphur in proper ratios. The DC electrical resistances were measured in the temperature range of 300 K-500 K. The temperature resistance curves of all the samples show phase transitions above a particular temperature. The UV and PL spectra of all the samples were compared and studied.

In recent years, modified theories of gravity have been extensively studied because of the discovery and confirmation of the current phase of accelerated expansion of the universe. The f(R,T) theory of gravity is one such theory, proposed by Harko et al. in 2011, in which R is the Ricci scalar and T is the trace of the stress-energy tensor. In this paper, we study Bianchi type V universe in f(R,T) theory of gravity with time varying cosmological constant and a quadratic equation of state p=αρ2-ρ, where α≠0 is a constant. We obtain exact solutions of the field equations for two cases: one with a volumetric expansion law and the other with an exponential expansion law. The physical features of the two models are discussed by examining the behaviour of some important cosmological parameters such as the Hubble parameter, the deceleration parameter etc. We find that the models have initial singularity and the physical parameters diverge at the initial epoch. The model 1, corresponding to the volumetric expansion law does not resemble ΛCDM model while the model 2, corresponding to the exponential expansion law, resembles ΛCDM model. The energy conditions of the models are also examined and found to be consistent with recent cosmological observations.

In this paper, the magnetohydrodynamic (MHD) flow of a ternary hybrid ferrofluid over a stretching/shrinking porous sheet in the presence of radiation and mass transpiration is studied. The ternary hybrid nanofluid is formed by suspending three types of nanoparticles for enhancing heat transfer. The nanoparticles of copper, (Cu) iron oxide (Fe3O4), and cobalt ferrite (CoFe2O4) are suspended in water in this study, producing in the combination Cu-Fe3O4-CoFe2O4-H2O. Brownian motion and thermophoresis are integrated into the ternary hybrid ferrofluid model. Similarity transformations convert the governing partial differential equations into ordinary differential equations. The boundary value problem (BVP) is used in the Maple computer software to solve transformed equations numerically. The computed results for relevant parameters such as velocity profile, temperature profile, skin friction coefficient, local Nusselt and Sherwood numbers are visually shown and explained in detail.

In the paper the physical properties and thermodynamic functions of monoborides ХВ (Х=Ti, Mn, Fe, Co) are studied with accounting for fluctuation processes. The research was performed for alloys with boron content of 9,0-15,0 % (wt.), the rest is metal Х (Х=Ti, Mn, Fe, Co). We use the microstructure analysis, the X-ray structural and the durometric analyses to determine the physical properties of alloys. In the paper it is determined the phase composition of Ti-B, Mn-B, Fe-B and Co-B alloys and physical properties of monoborides. In this paper for the first time it is determined the thermodynamic functions of monoborides using the Hillert and Staffansson model with accounting for the first degree approximation of high-temperature expansion for the free energy potential of binary alloys. We obtain the temperature dependences for such thermodynamic functions as Gibbs free energy, entropy, enthalpy and heat capacity Ср along with their values at the formation temperature for ХВ monoborides (Х=Ti, Mn, Fe, Co). The approach under consideration enables to give more thorough from the thermodynamic point of view description of monoborides formed from the liquid. The outcomes of the thermodynamic function calculation for TiB, MnB, CoB та FeB monoborides are in good agreement with experimental data and results of other authors.

The overview presents a historic retrospective and current state of research of structure, properties and application of hightemperature silicide materials in science and engineering. These materials, particularly construction and functional materials based on or involving silicide refractory metals, are a most important alternative class of materials which adequately complete with special alloys, intermetallic metals, and ceramics that are traditionally used at high (above 15000C) temperatures in oxidizing and other aggressive environments. The paper analyzes the data available on constitutional diagrams, particularly on molybdenum-silicon and tungsten-silicon systems. Also, it shows differences in descriptions of diagrams given by different authors and considers some crystallochemical and physical properties of some high-temperature silicides. The paper reviews areas of application of high-temperature silicide materials of various types (layered and multiple-phase composites, consolidated powders, film structure, three-dimensional materials), and presents details of the challenges encountered in the process of creation and application of high-temperature protecting silicide coatings, as well as possible ways to improve their performance. It is noted that lack of unified approach to presentation and correlation of research results as well as to description of real performance of materials is a substantial problem in creating new high-temperature silicide materials.

The paper is devoted to the changes in the X-ray luminescence spectra of nanoscale Y2O3 ceramics, namely the radiation associated with a self-trapped exciton. Additional heat treatment (annealing) of ceramic samples leads to changes in the exciton band of the spectra. These are a change in the shape and shift of the maximum of this band. Long-term irradiation of the samples by X-ray photons with an energy of 60 keV also led to changes in the exciton band. A theoretical model based on experimental data explains the changes in the spectra. The energy source of luminescence in this case is photoelectrons formed by energetic photons. Traps for these electrons are formed on the surface of submicrocrystals. Changes in the surface-to-volume ratio of crystals, as well as the frequencies of excited phonons and excitons are the basis for changes in the X-ray luminescence spectra of Y2O3 ceramics.

In this paper, a formula was derived for calculating the total current generated in a tunnel diode under the action of a microwave field and a magnetic field. In addition, the dependence of the total current of the tunnel diode on the total power induced by the microwave field is theoretically presented and compared with experimental data. For the total current in the tunnel diode, without taking into account the excess current, volt-ampere characteristics was obtained for cases with and without the influence of a microwave field.