East European Journal of Physics https://periodicals.karazin.ua/eejp <p>EEJP is an international peer-reviewed journal devoted to experimental and theoretical research on nuclear physics, cosmic rays and particles, high-energy physics, solid-state physics, plasma physics and controlled thermonuclear fusion, physics of charged particle beams, plasma electronics, radiation materials science, physics of thin films, condensed matter physics, functional materials and coatings, technical thermophysics and industrial power, medical physics and physical technologies in an interdisciplinary context.</p> <p>EEJP registered by the order of Ministry of Education and Science of Ukraine <strong>No. 1643 of 28.12.2019</strong>, and included in the list of scientific professional Editions of Ukraine (<strong>category “A”, specialty: 104, 105</strong>), in which results of dissertations for obtaining Ph.D. and Dr. Sci. degrees in physical and mathematical sciences can be published.</p> <p>The Journal is a part of the <strong>Web of Science Core Collection (ESCI)&nbsp;</strong>scientometric platform and indexed by&nbsp;<strong>SCOPUS</strong>.</p> <p>&nbsp;</p> en-US <p>Authors who publish with this journal agree to the following terms:<br><br></p> <ol type="a"> <ul> <li class="show">Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a&nbsp;<a href="http://creativecommons.org/licenses/by/4.0/" target="_new">Creative Commons Attribution License</a>&nbsp;that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.</li> </ul> </ol> <ol type="a"> <ul> <li class="show">Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.</li> </ul> </ol> <ol type="a"> <ul> <li class="show">Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See&nbsp;<a href="http://opcit.eprints.org/oacitation-biblio.html" target="_new">The Effect of Open Access</a>).</li> </ul> </ol> serhii.hirnyk@karazin.ua (Serhii Hirnyk) serhii.hirnyk@karazin.ua (Serhii Hirnyk) Fri, 10 Dec 2021 09:15:03 +0000 OJS http://blogs.law.harvard.edu/tech/rss 60 Recent Advances in Modeling of Perovskite Solar Cells Using SCAPS-1D: Effect of Absorber and ETM Thickness https://periodicals.karazin.ua/eejp/article/view/18031 <p>With the massive breakthrough recorded in the power conversion efficiency (PCE) of perovskite solar cells (PSCs) from 3.8 % to&nbsp;&gt;&nbsp;25&nbsp;%, PSCs have attracted considerable attention in both the academia and industries. However, some challenges remain as barrier in realizing its deployment. To develop a highly efficient PSCs as well as environmentally benign device, simulation and optimization of such devices is desirable. Its impractical as well as wastage of time and money to design a solar cell without simulation works. It minimizes not only the risk, time and money rather analyzes layers’ properties and role to optimize the solar cell to best performance. Numerical modeling to describe PV thin layer devices is a convenient tool to better understand the basic factors limiting the electrical parameters of the solar cells and to increase their performance. In this review article, we focused on the recent advances in modelling and optimization of PSCs using SCAPS-1D with emphasis on absorber and electron transport medium (ETM) thickness.</p> Eli Danladi, Douglas Saviour Dogo, Samuel Udeh Michael, Felix Omachoko Uloko, AbdulAzeez Omeiza Salawu Copyright (c) 2021 Eli Danladi, Douglas Saviour Dogo, Samuel Udeh Michael, Felix Omachoko Uloko, AbdulAzeez Omeiza Salawu https://periodicals.karazin.ua/eejp/article/view/18031 Fri, 10 Dec 2021 00:00:00 +0000 Comparison of Anatase and Rutile for Photocatalytic Application: the Short Review https://periodicals.karazin.ua/eejp/article/view/18041 <p>The dioxide titanium (TiO2) is attracting a great attention as semiconductor photocatalyst because of its high photoreactivity, non-toxicity, corrosion resistance, photostability, cheapness. It can be used in wide range of applications: air and water purification, hydrogen (H2) generation, CO2 reduction, in photovoltaic application and others. The efforts of scientists were applied to use solar light for dioxide titanium photocatalysis and to enhance the photocatalytic efficiency. In this article we review the properties difference of anatase and rutile modifications of TiO2. The anatase has a higher photoefficiency. The higher photoefficiency of anatase is due to longer lifetime of charge carriers (lifetime of e-/h+ in anatase on 3 order higher than in rutile). But anatase has higher band gap energy (3.2 eV or 388 nm) in comparison with rutile (3.0 eV or 414 nm). Thus, anatase becomes photosensitive in ultraviolet (UV) diapason of light, meanwhile rutile - in violet spectrum of visible light. It is desirable to obtain TiO2 semiconductor with properties combining best ones from anatase and rutile: higher photoreactivity and smaller band gap. It can be made by using external factors such as electric or magnetic fields, doping and etc.</p> Volodymyr Morgunov, Serhii Lytovchenko, Volodymyr Chyshkala, Dmytro Riabchykov, Dementii Matviienko Copyright (c) 2021 Volodymyr Morgunov, Serhii Lytovchenko, Volodymyr Chyshkala, Dmytro Riabchykov, Dementii Matviienko https://periodicals.karazin.ua/eejp/article/view/18041 Fri, 10 Dec 2021 00:00:00 +0000 The Effect of Hydrostatic Pressure and Cationic Vacancy on the Electronic and Magnetic Properties of the ZnSe:T Crystals (T = Ti, V, Cr, Mn, Fe, Co, Ni) https://periodicals.karazin.ua/eejp/article/view/18032 <p>The parameters of the spin-polarized electronic energy spectrum of ZnSe:T crystals (T = Ti, V, Cr, Mn, Fe, Co, Ni) are studied on the basis of a 2 × 2 × 2 supercell built on the basis of a ZnSe unit cell with a sphalerite structure. The supercell contains 64 atoms, with one Zn atom replaced by one transition 3d element T. The first stage of this study is to calculate in the ideal material ZnTSe parameters of electronic energy bands, dependent on the external hydrostatic pressure. At the second stage, the effect of pressure on the parameters of the electronic energy spectrum in the ZnTSe materials is investigated, taking into account the Zn vacancy. The calculations were performed using the Abinit program. For a better description of strongly correlated 3d electrons of the element T, a hybrid exchange-correlation functional PBE0 with an admixture of the Hartree-Fock exchange potential was used, in which the self-interaction error of these electrons is removed. Based on the obtained spin-polarized electron densities of states, the magnetic moments of the supercells were also determined. A significant effect of pressure on the parameters of electronic energy zones was revealed. So, the ideal ZnTiSe material at zero pressure is a metal for both spin values, but under pressure it becomes a semiconductor. The same material with a point defect, i.e. a vacancy at the site of the Zn atom, exhibits semiconductor properties for both spin orientations at zero pressure. It was found that vacancies radically change the parameters of electronic energy bands. The magnetic moments of the supercell, as integral values of the spin-polarized densities of electronic states, also reflect these changes. Thus, in ZnTiSe material without defects, the magnetic moments of the supercell are 1.92, 2.0 and 2.0, at pressures 0, 21 and 50&nbsp;GPa, respectively, while in the same material with a vacancy, the corresponding values are 0.39, 0.02 and 0.36. The ideal ZnVSe material at zero pressure is also a metal for both values of the spin moment, but in the presence of a cationic vacancy it is characterized by a pseudogap because the Fermi level is localized in the upper part of the valence band. Ideal ZnFeSe and ZnNiSe crystals are characterized by similar dependences of the electronic energy parameters on the pressure, for both spins. However, the same materials with a cationic vacancy are characterized by the Fermi level immersed in the valence band for a spin up.</p> Stepan Syrotyuk Copyright (c) 2021 Stepan Syrotyuk https://periodicals.karazin.ua/eejp/article/view/18032 Fri, 10 Dec 2021 00:00:00 +0000 Electrical and Photoelectric Properties of Organic-Inorganic Heterojunctions PEDOT:PSS/n-CdTe https://periodicals.karazin.ua/eejp/article/view/18034 <p>PEDOT: PSS thin films are widely used as transparent coatings in flexible semiconductor devices including solar cells. However, they are not widely used as transparent coatings in combination with crystal substrates. This work shows the possibility of using PEDOT:PSS thin films as a frontal transparent conducting layer in hybrid organic-inorganic Schottky type heterojunctions of the PEDOT:PSS/<em>n</em>‑CdTe, which were prepared by deposition of PEDOT:PSS thin films (using the spin-coating method) on crystalline cadmium telluride substrates. The current-voltage (in a wide temperature range) and capacitance-voltage (at room temperature) characteristics of heterojunctions were measurement and analyzed. It has been established that PEDOT:PSS/<em>n</em>-CdTe heterojunctions have good diode properties with a high rectification ratio RR≈10<sup>5</sup>, a potential barrier height φ<sub>0</sub>&nbsp;=&nbsp;0.95 eV, and series <em>R<sub>s</sub></em>&nbsp;=&nbsp;91 Ohm and shunt <em>R<sub>sh</sub></em>&nbsp;=&nbsp;5.7&nbsp;×&nbsp;10<sup>7</sup> Ohm resistances. Analysis of the forward branches of the <em>I–V</em> characteristics of heterojunctions showed that the dominant charge transfer mechanisms are determined by the processes of radiative recombination at low biases (3kT/e &lt;<em>V</em> &lt;0.3 V) and tunneling through a thin depleted layer at high biases (0.3 V &lt;<em>V</em> &lt;0.6 V). Capacity-voltage characteristics are plotted in the Mott-Schottky coordinate, taking into account the influence of series resistance, measured at a frequency of 1 MHz. Used the C-V characteristic was determined the value of the built-in potential <em>V<sub>c</sub></em>&nbsp;=&nbsp;1.32 V (it correlates well with the cutoff voltage determined from the current-voltage characteristics) and the concentration of uncompensated donors in the <em>n</em>-CdTe substrate N<sub>D</sub>-N<sub>A</sub>&nbsp;=&nbsp;8.79&nbsp;×&nbsp;10<sup>14</sup>&nbsp;cm<sup>-3</sup>. Although the photoelectric parameters of unoptimized PEDOT:PSS/<em>n</em>-CdTe heterojunctions are low, their photodiode characteristics (Detectivity <em>D<sup>*</sup></em>&gt;&nbsp;10<sup>13</sup> Jones) are very promising for further detailed analysis and improvement. The proposed concept of a hybrid organic-inorganic heterojunction also has potential for use in inexpensive γ- and X-ray detectors.</p> Hryhorii Parkhomenko, Mykhailo Solovan, Andrii Mostovyi, Ivan Orletskyi, Viktor Brus Copyright (c) 2021 Hryhorii P. Parkhomenko, Mykhailo M. Solovan, Andrii I. Mostovyi, Ivan G. Orletskyi, Viktor V. Brus https://periodicals.karazin.ua/eejp/article/view/18034 Fri, 10 Dec 2021 00:00:00 +0000 Family of the Atomic Radial Basis Functions of Three Independent Variables Generated by Helmholtz-Type Operator https://periodicals.karazin.ua/eejp/article/view/18035 <p>The paper presents an algorithm for constructing the family of the atomic radial basis functions of three independent variables &nbsp;generated by Helmholtz-type operator, which may be used as basis functions for the implementation of meshless methods for solving boundary-value problems in anisotropic solids. Helmholtz-type equations play a significant role in mathematical physics because of the applications in which they arise. In particular, the heat equation in anisotropic solids in the process of numerical solution is reduced to the equation that contains the differential operator of the special form (Helmholtz-type operator), which includes components of the tensor of the second rank, which determines the anisotropy of the material. The family of functions &nbsp;is infinitely differentiable and finite (compactly supported) solutions of the functional-differential equation of the special form. The choice of compactly supported functions as basis functions makes it possible to consider boundary-value problems on domains with complex geometric shapes. Functions &nbsp;include the shape parameter , which allows varying the size of the support and may be adjusted in the process of solving the boundary-value problem. Explicit formulas for calculating the considered functions and their Fourier transform are obtained. Visualizations of the atomic functions &nbsp;and their first derivatives with respect to the variables &nbsp;and &nbsp;at the fixed value of the variable &nbsp;for isotropic and anisotropic cases are presented. The efficiency of using atomic functions &nbsp;as basis functions is demonstrated by the solution of the non-stationary heat conduction problem with the moving heat source. This work contains the results of the numerical solution of the considered boundary-value problem, as well as average relative error, average absolute error and maximum error are calculated using atomic radial basis functions &nbsp;and multiquadric radial basis functions.</p> Denys Protektor Copyright (c) 2021 Denys O. Protektor https://periodicals.karazin.ua/eejp/article/view/18035 Fri, 10 Dec 2021 00:00:00 +0000 Application of Particular Solutions of the Burgers Equation to Describe the Evolution of Shock Waves of Density of Elementary Steps https://periodicals.karazin.ua/eejp/article/view/18037 <p>Particular solutions of the Burgers equations (BE) with zero boundary conditions are investigated in an analytical form. For values of the shape parameter &nbsp;greater than 1, but approximately equal to 1, the amplitude of the initial periodic perturbations depends nonmonotonically on the spatial coordinate, i.e. the initial perturbation can be considered as a shock wave. Particular BE solutions with zero boundary conditions describe a time decrease of the amplitude of initial nonmonotonic perturbations, which indicates the decay of the initial shock wave. At large values of the shape parameter , the amplitude of the initial periodic perturbations depends harmoniously on the spatial coordinate. It is shown that over time, the amplitude and the spatial derivative of the profile of such a perturbation decrease and tend to zero. Emphasis was put on the fact that particular BE solutions can be used to control numerical calculations related to the BE-based description of shock waves in the region of large spatial gradients, that is, under conditions of a manifold increase in spatial derivatives. These solutions are employed to describe the profile of a one-dimensional train of elementary steps with an orientation near &lt;100&gt;, formed during the growth of a NaCl single crystal from the vapor phase at the base of a macroscopic cleavage step. It is shown that the distribution of the step concentration with distance from the initial position of the macrostep adequately reflects the shock wave profile at the decay stage. The dimensionless parameters of the wave are determined, on the basis of which the estimates of the characteristic time of the shock wave decay are made.</p> Oksana Andrieieva, Victor Tkachenko, Oleksandr Kulyk, Oksana Podshyvalova, Volodymyr Gnatyuk, Toru Aoki Copyright (c) 2021 Oksana L. Andrieieva, Victor I. Tkachenko, Oleksandr P. Kulyk, Oksana V. Podshyvalova, Volodymyr A. Gnatyuk, Toru Aoki https://periodicals.karazin.ua/eejp/article/view/18037 Fri, 10 Dec 2021 00:00:00 +0000 On the Impact Parameter Dependence of the Ionization Energy Loss of Fast Negatively Charged Particles in an Oriented Crystal https://periodicals.karazin.ua/eejp/article/view/18038 <p>When a fast charged particle passes through matter, it loses some of its energy to the excitation and ionization of atoms. This energy loss is called ionization energy loss. In rather thin layers of matter, the value of such energy loss is stochastic. It is distributed in accordance with the law, which was first received by L.D.&nbsp;Landau. In amorphous substances, such a distribution (or spectrum), known as the Landau distribution, has a single maximum that corresponds to the most probable value of particle energy loss. When a particle moves in crystal in a planar channeling mode, the probability of close collisions of the particle with atoms decreases (for a positive particle charge) or increases (for a negative charge), which leads to a change in the most probable energy loss compared to an amorphous target. It has recently been shown that during planar channeling of negatively charged particles in a crystal, the distribution of ionization energy loss of the particles is much wider than in the amorphous target. In this case, this distribution can be two-humped, if we neglect the incoherent scattering of charged particles on the thermal oscillations of the crystal atoms and the electronic subsystem of the crystal. This paper explains the reason for this distribution of ionization energy loss of particles. The ionization energy loss distribution of high-energy negatively charged particles which move in the planar channeling mode in a silicon crystal are studied with the use of numerical simulation. The dependence of this distribution on the impact parameter of the particles with respect to atomic planes is considered. The dependence of the most probable ionization energy loss of particles on the impact parameter is found. It is shown that, for a large group of particles, the most probable ionization energy loss during planar channeling in a crystal is lower than in an amorphous target.</p> Sergii Trofymenko, Igor Kyryllin, Oleksandr Shchus Copyright (c) 2021 Sergii V. Trofymenkoa, Igor V. Kyryllina, Oleksandr P. Shchus https://periodicals.karazin.ua/eejp/article/view/18038 Fri, 10 Dec 2021 00:00:00 +0000 Structural, Electrical and Optical Properties of CuO Thin Films Obtained by Reactive Magnetron Sputtering https://periodicals.karazin.ua/eejp/article/view/18042 <p>CuO thin films were produced by the method of reactive magnetron sputtering at direct current in a universal vacuum system Leybold-Heraeus L560 on glass substrates, the temperature of which was: 300 K and 523 K. The structural, electrical and optical properties for the obtained samples of CuO thin films were studied, namely: elemental composition, distribution of elements on the surface, which are part of these films, grain size, activation energy, optical band gap, refractive index, analysis of curves of transmission and reflection spectra for CuO thin films deposited on glass substrates. The elemental composition of the thin films and the surface morphology were performed using a scanning electron microscope (MIRA3 FEG, Tescan) equipped with a reflected electron detector (BSE) and an energy-dispersed X-ray detector (EDX). It was found that the grain size for films obtained at a lower substrate temperature D is ~&nbsp;16&nbsp;nm, and for films obtained at a higher temperature - D ~ 26 nm. On the diffractograms of CuO thin films, a higher peak intensity is observed for thin films obtained at higher CuO no.&nbsp;2 substrate temperatures, which may be due to better structural perfection of thin films and larger grain size. From the study of electrical properties, it was found that the temperature dependences of the electrical resistance for CuO thin films have a semiconductor character, ie the resistance decreases with increasing&nbsp;<em>T</em>. The surface resistance of the films was measured by the four-probe method: no.&nbsp;1- ρ = 18,69 kΩ/¨, sample no.&nbsp;2 – ρ&nbsp;=&nbsp;5,96&nbsp;kΩ/¨. Based on independent measurements of the reflection and transmission coefficients, the optical band gap was determined for the two samples by extrapolation of the rectilinear section of the curve (<em>αhν</em>)<sup>2</sup> = <em>f</em> (<em>hv</em>) to the <em>hv</em> axis. For the sample CuO №1 <em>E<sub>g</sub><sup>op</sup></em> = 1.62 eV; for the sample CuO no.&nbsp;2 <em>E<sub>g</sub><sup>op</sup></em> = 1.65 eV. For CuO no.&nbsp;2 thin films, the envelope method was also used to determine the basic optical coefficients <em>E<sub>g</sub><sup>op</sup></em> = 1.72 eV, and the obtained <em>E<sub>g</sub><sup>op</sup></em> values determined by the two methods correlate well with each other.</p> Serhii Kuryshchuk, Taras Kovalyuk, Hryhorii Parkhomenko, Mykhailo Solovan Copyright (c) 2021 Serhii I. Kuryshchuk, Taras T. Kovalyuk, Hryhorii P. Parkhomenko, Mykhailo M. Solovan https://periodicals.karazin.ua/eejp/article/view/18042 Fri, 10 Dec 2021 00:00:00 +0000 Thermal-Vacuum Method for Obtaining Nanodispersed Zirconium Dioxide https://periodicals.karazin.ua/eejp/article/view/18043 <p>An energy-efficient thermal-vacuum method for continuous production of nanodispersed powder of amorphous zirconium dioxide from zirconium hydroxide has been developed. This approach is based on a principle of creating an aerodynamic flow with an initial powder-like material in the cavity of the heating element of a thermal-vacuum installation. In this way, short-term contacts of particles of zirconium hydroxide with the inner surface of the heating element made in the form of the winding helical are created. As a result, the crushing of the particles is carried out due to the high thermal stresses in the particles contacted. This process is aggravated by the presence of residual moisture in the original powdery material. Transformations of the zirconium hydroxide in the process of thermal-vacuum treatment have been investigated. Amorphous dioxide has been obtained. The study of structural composition of the material in the initial state and processed in a thermal-vacuum installation was carried out using X-ray analysis and scanning microscopy. Experimental data on the structural-phase composition of the original material and data on the closest structural prototypes of crystalline-impurity compounds are presented. They are also given data on the volume of crystal cells and estimates of the molar concentration of the components. A mass spectrometric assessment of the elemental composition of the obtained zirconium dioxide is given. Thermal-vacuum method allows toobtain highly dispersed zirconium dioxide in its amorphous state directly from zirconium hydroxide without using liquid media and, moreover, in a short time – within 15...20 s.</p> Volodymyr Kutovyi, Dmitry Malykhin, Volodymyr Virych, Ruslan Vasilenko Copyright (c) 2021 Volodymyr O. Kutovyi, Dmitry G. Malykhin, Volodymyr D. Virych, Ruslan L. Vasilenko https://periodicals.karazin.ua/eejp/article/view/18043 Fri, 10 Dec 2021 00:00:00 +0000 GEANT4 Modeling of the Bremsstrahlung Converter Optimal Thickness for Studying the Radiation Damage Processes in Organic Dyes Solutions https://periodicals.karazin.ua/eejp/article/view/18044 <p>The study of the processes occurring in a matter when ionizing radiation passes through is important for solving various problems. Examples of such problems are applied and fundamental problems in the field of radiation physics, chemistry, biology, medicine and dosimetry. This work is dedicated to computer modeling of the parameters of a tungsten converter for studying the processes of radiation damage during the interaction of ionizing radiation with solutions of organic dyes. Simulation was carried out in order to determine the optimal thickness of the converter under predetermined experimental conditions. Experimental conditions include: energies and type of primary particles, radiation intensity, target dimensions, relative position of the radiation source and target. Experimental studies of the processes of radiation damage occurring in solutions of organic dyes are planned to be carried out using the linear electron accelerator "LINAC-300" of the National Scientific Center "Kharkov Institute of Physics and Technology". Electrons with 15&nbsp;MeV energy are chosen as primary particles. The interaction of electrons with the irradiated target substances is planned to be studied in the first series of experiments. Investigations of the interaction of gamma quanta with the target matter will be carried out in the second series of experiments. The tungsten converter is used to generate a flux of bremsstrahlung gamma rays. One modeling problem is determination of the converter thickness at which the flux of bremsstrahlung gamma will be maximal in front of the target. At the same time, the flow of electrons and positrons in front of the target should be as low as possible. Another important task of the work is to identify the possibility of determining the relative amount of radiation damage in the target material by the Geant4-modeling method. Radiation damage of the target substance can occur due to the effect of bremsstrahlung, as well as electrons and positrons. Computational experiments were carried out for various values of the converter thickness – from 0&nbsp;mm (no converter) to 8&nbsp;mm with a step of 1&nbsp;mm. A detailed analysis of the obtained data has been performed. As a result of the data analysis, the optimal value of the tungsten converter thickness was obtained. The bremsstrahlung flux in front of the target is maximum at a converter thickness of 2&nbsp;mm. But at the same time, the flux of electrons and positrons crossing the boundaries of the target does not significantly affect the target. The computational experiment was carried out by the Monte Carlo method. A computer program in C++ that uses the Geant4 toolkit was developed to perform calculations. The developed program operates in a multithreaded mode. The multithreaded mode is necessary to reduce the computation time when using a large number of primary electrons. The G4EmStandardPhysics_option3 model of the PhysicsList was used in the calculations. The calculations necessary for solving the problem were carried out using the educational computing cluster of the Department of Physics and Technology of V.N. Karazin Kharkiv National University.</p> Tetiana Malykhina, Vladimir Kovtun, Valentin Kasilov, Sergey Gokov Copyright (c) 2021 Tetiana V. Malykhina, Vladimir E. Kovtun, Valentin I. Kasilov, Sergey P. Gokov https://periodicals.karazin.ua/eejp/article/view/18044 Fri, 10 Dec 2021 00:00:00 +0000 Thermodynamic and Kinetic Parameters of the Processes of Deuterium Interaction with Tungsten Protective Coatings https://periodicals.karazin.ua/eejp/article/view/18045 <p>The effect of radiation damage on the retention of deuterium in tungsten (W) was examined. A vacuum-arc plasma source with magnetic stabilization of the cathode spot was used for tungsten coatings preparation. W samples were treated with D ions at temperatures 300‑600 K with a fluence of (1 – 10) ·10<sup>20</sup> D<sub>2</sub><sup>+</sup>/m<sup>2</sup> and ion energies of 12 keV/D<sub>2</sub><sup>+</sup>. The influence of radiation damage on microstructure and accumulation of deuterium implanted in W samples at room temperature and after annealing have been studied. Thermal desorption (TD) spectroscopy was used to determine the D retained throughout the bulk of the sample. The structure of TD spectra represents the multi-stage process of deuterium release suggesting the trapping of gas atoms by a number of defect types. Computational evaluation of deuterium desorption within the framework of the diffusion-trapping model allows to associate characteristics of experimental TD spectra with specific trapping sites in the material. Experimental TD spectrum was fitted by assigning four binding energies of 0.55 eV, 0.74 eV, 1.09 eV and 1.60 eV for the peaks with maxima at 475, 590, 810 and 1140 K, respectively. The low temperature peak in the TD spectra is associated with desorption of deuterium bounded to the low energy natural traps, whereas the other peaks are related to the desorption of deuterium bounded to the high energy ion induced traps: monovacancies and vacancy clusters.</p> Sergiy Karpov, Valeryi Ruzhytskyi, Galyna Tolstolutskaya, Ruslan Vasilenko, Oleksandr Kuprin, Sergiy Leonov Copyright (c) 2021 Sergiy Karpov, Valeryi Ruzhytskyi, Galyna Tolstolutskaya, Ruslan Vasilenko, Oleksandr Kuprin, Sergiy Leonov https://periodicals.karazin.ua/eejp/article/view/18045 Fri, 10 Dec 2021 00:00:00 +0000 Interactions of Novel Phosphonium Dye with Lipid Bilayers: A Fluorescence Study https://periodicals.karazin.ua/eejp/article/view/18046 <p>The phosphonium-based optical probes attract ever growing interest due to their excellent chemical and photophysical stability, high aqueous solubility, long wavelength absorption and emission, large extinction coefficient, high fluorescence quantum yield, low cytotoxicity, etc. The present study was focused on assessing the ability of the novel phosphonium dye TDV to monitor the changes in physicochemical properties of the model lipid membranes. To this end, the fluorescence spectral properties of TDV have been explored in lipid bilayers composed of zwitterionic lipid phosphatidylcholine (PC) and its mixtures with cholesterol (Chol) or/and anionic phospholipid cardiolipin (CL). It was observed that in the buffer solution TDV possesses one well-defined fluorescence peak with the emission maximum at 533 nm. The dye transfer from the aqueous to lipid phase was followed by the enhancement of the fluorescence intensity coupled with a red shift of the emission maximum up to 67 nm, depending on the liposome composition. The quantitative information about the dye partitioning into lipid phase of the model membranes was obtained through approximating the experimental dependencies of the fluorescence intensity increase <em>vs </em>lipid concentration by the partition model. Analysis of the partition coefficients showed that TDV has a rather high lipid-associating ability and displays sensitivity to the changes in physicochemical properties of the model lipid membranes. The addition of CL, Chol or both lipids to the PC bilayer gives rise to the increase of the TDV partition coefficients compared to the neat PC membranes. The enhancement of the phosphonium dye partitioning in the CL and Chol-containing lipid bilayers has been attributed to the cardiolopin- and cholesterol-induced changes in the structure and physicochemical characteristics of the polar membrane region.</p> Olga Zhytniakivska Copyright (c) 2021 Olga Zhytniakivska https://periodicals.karazin.ua/eejp/article/view/18046 Fri, 10 Dec 2021 00:00:00 +0000 Clinical Commissioning and Dosimetric Verification of the Raystation Treatment Planning System https://periodicals.karazin.ua/eejp/article/view/18047 <p>Background: The software used by treatment planning systems (TPS) plays an important role for treatments using radiation. The accuracy of the calculated dose in radiation treatments depends on the assumptions made by the TPS. In this study, we summarize our methods and results regarding clinical commissioning of the basic functions needed for photon therapy. Materials and Method: Measurements were obtained for the 6 and 15 MV photon energies obtained from the Siemens Artiste linear accelerator device. Important data such as percent deep dose, profile and output measurements were taken in the water phantom and transferred to the RayStation Treatment Planning System. Results: When the absolute dose values calculated by the RayStation TPS are compared with the water phantom data, the differences obtained are less than 3%. When the 2-dimensional quality control of asymmetrical areas and patients with IMRT plan was controlled by gamma analysis method, the gamma rate was more than 95%. Conclusion: One of the most important quality control tests is TPS acceptance tests, which must be performed before clinical use. In this study, in which we checked the basic dose measurement and patient planning, it was seen that the RayStation TPS can be used in patient treatment for clinical use. The doses calculated by the RayStation TPS were found to be reliable and within the expected accuracy range. These results are sufficient for the application of 3-dimensional conformal radiotherapy (3D-CRT) and IMRT technique.</p> Taylan Tuğrul Copyright (c) 2021 Taylan Tuğrul https://periodicals.karazin.ua/eejp/article/view/18047 Fri, 10 Dec 2021 00:00:00 +0000 Investigation of the Structural Composition of Fe-Mn-Si-Ti-Al-N-C Alloys and the Solubility of Elements in α-Iron https://periodicals.karazin.ua/eejp/article/view/18048 <p>The study of the structural components of Fe-Mn-Si-Ti-Al-N-C with the carbon content of 0.50-0.60% (wt.), Silicon 0.80-0.90% (wt.), Manganese 0.90-0.95% ( wt. ), Aluminum - 0.20-0.30% (wt.), Titanium - 0.02-0.03% (wt.), Nitrogen - 0.015-0.02% (wt.), the rest - iron. Microstructural, micro-X-ray spectral and X-ray phase analyzes were used to determine the structural state of the alloys. It is shown that after crystallization and a number of phase transformations the structure of the alloy was presenteda - iron alloyed with cementite, oxides, nitrides and carbonitrides. Using the quasi-chemical method, the free energy dependence of the solid solution of α-iron alloyed with silicon, manganese and titanium was obtained. In α-iron, it can dissolve up to 0.016% (at.) Carbon, manganese up to 1.3% (at.), Silicon - 1.0% (at.), and titanium up to 0.5% (at.), which is consistent with experimental results.</p> Nataliia Filonenko, Olexander Babachenko, Hanna Kononenko, Alexander Baskevich Copyright (c) 2021 Nataliia Filonenko, Aleksander Babachenko, Hanna Kononenko, Alexander Baskevic https://periodicals.karazin.ua/eejp/article/view/18048 Fri, 10 Dec 2021 00:00:00 +0000 Simulation of a High-Energy Electron Beam Transmission Through Titanium and Kapton® Thin Films https://periodicals.karazin.ua/eejp/article/view/18049 <p>The results of computer simulation of the high-energy electrons passage through thin layers of titanium (Ti) and polyimide Kaptonâ (C<sub>22</sub>H<sub>10</sub>N<sub>2</sub>O<sub>5</sub>) in the energy range from 3&nbsp;MeV to 20&nbsp;MeV are presented. Simulation is carried out using the Geant4 toolkit. The number of primary electrons is 6.24×10<sup>7</sup> for each series of calculations. The thickness of the titanium foil in the model experiment is 50&nbsp;µm, the thickness of the Kaptonâ film is 110&nbsp;µm. The energies of primary electrons are chosen as following: 3&nbsp;MeV, 5&nbsp;MeV, 10&nbsp;MeV, 15&nbsp;MeV, and 20&nbsp;MeV. The purpose of the calculations is to reveal the possibility of using the Kaptonâ film in the output devices of linear electron accelerators. It was necessary to calculate the probable values of the energy absorbed in a Kaptonâ film and in a titanium foil for each value of primary electrons energy. Another important characteristic is the divergence radius of the electron beam at a predetermined distance from the film, or the electron scattering angle. As a result of calculations, the energy spectra of bremsstrahlung gamma-quanta, formed during the passage of electrons through the materials of the films, are obtained. The most probable values of the energy absorbed in the titanium foil and in the Kaptonâ film are calculated. The scattering radii of an electron beam for the Kaptonâ film and also for the titanium foil at a distance of 20&nbsp;centimeters are estimated. These calculations are performed for electron energies of 3&nbsp;MeV, 5&nbsp;MeV, 10&nbsp;MeV, 15&nbsp;MeV, and 20&nbsp;MeV. A comparative analysis of the obtained results of computational experiments is carried out. It is shown that the ratio of the total amount of bremsstrahlung gamma quanta in the case of use the Kaptonâ film is approximately 0.56 of the total amount of bremsstrahlung gamma quanta when using the titanium foil. The coefficients of the ratio of the electrons scattering radius most probable value after passing through Kaptonâ to the most probable value of the scattering radius after passing through titanium are from 0.62 at electrons energy of 3&nbsp;MeV to 0.57 at electrons energy of 20&nbsp;MeV. The analysis of the calculated data showed that the use of Kaptonâ (C<sub>22</sub>H<sub>10</sub>N<sub>2</sub>O<sub>5</sub>) as a material for the manufacture of output devices for high-energy electron beams is more preferable in comparison to titanium films, since the use of Kaptonâ instead of titanium makes it possible to significantly reduce the background of the generated bremsstrahlung gamma quanta and reduce the scattering radius of the electron beam.</p> Tetiana Malykhina, Stepan Karpus, Oleg Shopen, Valerii Prystupa Copyright (c) 2021 Tetiana V. Malykhina, Stepan G. Karpus, Oleg O. Shopen, Valerii I. Prystupa https://periodicals.karazin.ua/eejp/article/view/18049 Fri, 10 Dec 2021 00:00:00 +0000 Research of Interaction Processes of Fast and Thermal Neutrons with Solution of Organic Dye Methyl Orange https://periodicals.karazin.ua/eejp/article/view/18050 <p>The emergence of powerful sources of ionizing radiation, the needs of nuclear energy, technology and medicine, as well as the need to develop reliable methods of protection against the harmful effects of penetrating radiation stimulated the development of such branches of science as radiation chemistry, radiation biology, radiation medicine. When an organic dye solution is exposed to ionizing radiation, it irreversibly changes color. As a result, the absorbed dose can be determined. The processes of interaction of neutron fluxes with an aqueous solution of an organic dye methyl orange (МО)&nbsp;–&nbsp;C<sub>14</sub>H<sub>14</sub>N<sub>3</sub>О<sub>3</sub>SNa, containing and not containing 4% boric acid, have been investigated. The work was carried out on a LINAC LUE-300&nbsp;at NSC&nbsp;KIPT. A set of tungsten plates was used as a neutron-generating target. The electron energy was 15&nbsp;MeV, the average current was 20&nbsp;μA. The samples were located behind the lead shield and without it, with and without a moderator. Using the GEANT4 toolkit code for this experiment, neutron fluxes and their energy spectra were calculated at the location of experimental samples without a moderator and with a moderator of different thickness (1-5&nbsp;cm). An analysis of the experimental results showed that when objects without lead shielding and without a moderator are irradiated, the dye molecules are completely destroyed. In the presence of lead protection, 10% destruction of the dye molecules was observed. When a five-centimeter polyethylene moderator was installed behind the lead shield, the destruction of dye molecules without boric acid on thermal neutrons was practically not observed. When the fluxes of thermal and epithermal neutrons interacted with a dye solution containing 4% boric acid, 30% destruction of dye molecules was observed due to the exothermic reaction 10B (n, α). The research has shown that solutions of organic dyes are a good material for creating detectors for recording fluxes of thermal and epithermal neutrons. Such detectors can be used for radioecological monitoring of the environment, in nuclear power engineering and nuclear medicine, and in the field of neutron capture therapy research in particular.</p> <p><strong>Keywords:</strong> organic dye, neutrons, dosimeters</p> Sergey Gokov, Yuri Kazarinov, Sergiy Kalenik, Valentin Kasilov, Tetiana Malykhina, Yegor Rudychev, Vitaliy Tsiats’ko Copyright (c) 2021 Sergey P. Gokov, Yuri G. Kazarinov, Sergiy A. Kalenik, Valentin Y. Kasilov, Tetiana V. Malykhina, Yegor V. Rudychev, Vitaliy V. Tsiats’ko https://periodicals.karazin.ua/eejp/article/view/18050 Fri, 10 Dec 2021 00:00:00 +0000 Positive Deviation of the Hall-Petch Relationship for Aluminum Condensates Alloyed with Iron https://periodicals.karazin.ua/eejp/article/view/18051 <p>The structure and strength properties of vacuum aluminum condensates alloyed with iron in the concentration range of 0.1 – 3.2&nbsp;at.&nbsp;% is studied in the paper. It is shown that up to a concentration of about 2 at. % Fe, the grain size decreases, the strength properties increase and the lattice parameter values of these objects remain unchanged. It is found that at an iron concentration of up to&nbsp;~&nbsp;2&nbsp;at.&nbsp;% its atoms are concentrated in the grain boundaries of the aluminum matrix metal in the form of grain boundary segregation. At high concentrations, the structure of condensates is a supersaturated solution of iron in the FCC crystal lattice of aluminum. Highly dispersed Al<sub>13</sub>Fe<sub>4</sub> intermetallic compounds are present at the grain boundaries and within the volume of grains. It has been found that the Hall-Petch coefficient for one-component aluminum condensates is 0.04&nbsp;MPa·m<sup>1/2</sup>, which is typical for this metal. For Al-Fe condensates, a positive deviation from the Hall-Petch dependence is observed and the coefficient <em>k</em> increases to 0.4 MPa·m<sup>1/2 </sup>for a structure with grain boundary segregations and to 0.14&nbsp;MPa·m<sup>1/2</sup> for condensates containing intermetallic compounds. The obtained experimental results are explained by the different structural-phase state of the grain boundaries of the aluminum matrix.</p> Evgeniy Lutsenko, Anatoly Zubkov , Maria Zhadko, Eduard Zozulya Copyright (c) 2021 Evgeniy Lutsenko, Anatoly Zubkov, Maria Zhadko, Eduard Zozulya http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18051 Fri, 10 Dec 2021 00:00:00 +0000 X-Ray Induced Light Emission of Yttrium Oxide https://periodicals.karazin.ua/eejp/article/view/18052 <p>The paper presents the experimental results of light radiation from Y<sub>2</sub>O<sub>3</sub> ceramics caused by X-rays with energy up to 50 keV. The samples were made from commercial Y<sub>2</sub>O<sub>3</sub> nanopowder by pressing and subsequent sintering in air at different temperatures from 1300 to 1500°С. Some samples sintered at 1500°C were additionally annealed at 1000°C for 10 hours. X-ray diffraction analysis of all samples did not reveal differences in the crystal structure that could be explained by heat treatment during sintering and annealing. The spectra of light emission in the wavelength range of 250-750&nbsp;nm showed the presence of radiation from the electronic transitions of YO structures on the background of the luminescence of trivalent yttrium oxide. The presence of such lines of YO systems were observed also for the powder, which allows us to conclude that these structures appear on the surface of the crystallites during production. As the sintering temperature of the sample increased, the intensity of optical radiation increased. A significant difference in the effect of both temperature and sintering (annealing) time on the intensity of light emission of yttrium oxide was revealed. The intensity of the luminescent band, which is associated with the self-trapped exciton, increased with increasing thermal contribution (to estimate the contribution, we introduced a parameter equal to the product of temperature and the time of thermal action). The increase in spectral intensity in the second, third, fourth, and fifth line systems (especially for the system of lines with a maximum of&nbsp;λ=573.5&nbsp;nm) considerably exceeded the one for self-trapped exciton. Our experimental results on the second, fourth and fifth systems of lines, which coincide well with the molecular lines YO, suggest that the heat treatment of the samples sintered from pressed Y<sub>2</sub>O<sub>3</sub> powder leads to an increase in YO structures on the surface of the crystallites.</p> Sergiy Kononenko, Oganes Kalantaryan, Vitaliy Zhurenko, Sergii Lytovchenko, Ruslan Skyba Copyright (c) 2021 Sergiy Kononenko, Oganes Kalantaryan, Vitaliy Zhurenko, Volodymyr Chishkala, Sergii Lytovchenko, Ruslan Skyba http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18052 Fri, 10 Dec 2021 00:00:00 +0000 Photoluminescence, Impedance, Thermal Characteristics and Hirshfeld Surface Analysis of Potassium Bisulphate Single Crystals for Third Order NLO Applications https://periodicals.karazin.ua/eejp/article/view/18053 <p>Good quality potassium bisulphate (KHS) single crystals have been grown by slow evaporation method at room temperature. The KHS crystal was found to be crystallizing in orthorhombic crystal structure with Pbca space group. The photoluminescence behaviour of the crystal was analysed in the visible region. This study disclosed that the grown KHS crystal has intense blue emission peak at 490 nm. Impedance analysis was performed to investigate the frequency dependent electrical characteristics at various temperatures. From the impedance studies the bulk resistance, grain boundary resistance and DC conductivity values of the grown crystal were found out. The KHS crystal was subjected to TGA/DTA and the results have been investigated. The electrical parameters like Fermi energy and average energy gap of KHS crystal have been determined. The evaluated values are used to estimate the electronic polarizability. The intermolecular interactions were predicted using Hirshfeld surface analysis. This analysis exhibited that the utmost contribution to the crystal structure was the K⋯O (46.7%) interaction. The 2D fingerprint plot provides the percentage contribution of each atom-to-atom interaction. Since KHS material is a centrosymmetric crystal, it could be used for third order nonlinear optical (NLO) applications.</p> K. Thilaga, P. Selvarajan, S.M. Abdul Kader Copyright (c) 2021 K. Thilaga, P. Selvarajan, S.M. Abdul Kader http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18053 Fri, 10 Dec 2021 00:00:00 +0000 Plasma Conversion of CO2 in DC Glow Discharge with Distributed Gas Injection and Pumping https://periodicals.karazin.ua/eejp/article/view/18054 <p>Accumulation of carbon dioxide in the Earth's atmosphere leads to an increase in the greenhouse effect and, as a consequence, to significant climate change. Thus, the demand to develop effective technologies of carbon dioxide conversion grows year to year. Additional reason for research in this direction is the intention of Mars exploration, since 96% of the Martian atmosphere is just carbon dioxide, which can be a source of oxygen, rocket fuel, and raw materials for further chemical utilization. In the present paper, the plasma conversion of carbon dioxide have been studied in the dc glow discharge at the gas pressure of 5 Torr in a chamber with distributed gas injection and evacuation from the same side for the case of narrow interelectrode gap. The conversion coefficient and the energy efficiency of the conversion were determined using mass spectrometry of the exhaust gas mixture in dependence on CO<sub>2</sub> flow rate and the discharge current and voltage. Maximum conversion rate was up to 78% while the energy efficiency of the conversion was always less than 2%. It was found that the discharge at this pressure can operate in normal and abnormal modes and the transition between the modes corresponds just to the maximum value of the conversion coefficient for a given gas flow. It was shown that even in anomalous regime, when the cathode is completely covered by the discharge, the discharge contraction occurs in whole range of parameters studied. The anode glow and the plasma column outside the cathode layer occupy the central part of the discharge only that reduces the conversion efficiency. Optical emission spectra from the carbon dioxide plasma were measured in the range of 200-1000 nm, which allowed to make a conclusion that the Oxygen atom emission is mostly origins from the exited atoms appearing after dissociation rather than after electron impact excitation.</p> Valeriy Lisovskiy, Stanislav Dudin, Pavlo Platonov, Vladimir Yegorenkov Copyright (c) 2021 Valeriy A. Lisovskiy, Stanislav V. Dudin, Pavlo P. Platonov, Vladimir D. Yegorenkov http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18054 Fri, 10 Dec 2021 00:00:00 +0000 Concept of Neutron Source Creation for Nuclear Medicine on the Basis of Linear Electron Accelerator https://periodicals.karazin.ua/eejp/article/view/18055 <p>We review the current status of the development of sources of epithermal neutrons sources based on reactors and accelerators for boron neutron capture therapy (BNCT), a promising method of malignant tumor treatment. The scheme is proposed of the source prototype for the production of thermal and epithermal neutrons using the delayed neutrons generated with help of linear electron accelerator at the target containing the fissile material. The results of an experiment are presented in which the half-life curves of radioactive nuclei formed during fission and emitting delayed neutrons are measured. It is shown that an activated target containing fissile material is a compact small-sized source of delayed neutrons. It can be delivered to the shaper, where, using a moderator, an absorber, and a collimator, neutrons of thermal or epithermal energies are formed over a certain period of time, after which this target is sent to the activator, and another target comes in its place. Thus, a pulsed neutron flux is formed. Such a neutron beam can be used in nuclear medicine, in particular, in neutron capture therapy in the treatment of cancer. An important task in the implementation of neutron capture therapy, when irradiating patients, is to control both the intensity and the energy spectrum of the neutron flux. To solve this problem, an earlier developed activation-type neutron ball spectrometer can be used, which will allow optimization of various parameters of the shaper, collimator and filters in order to obtain the most powerful neutron fluxes.</p> Valentin Kasilov; Sergey Gokov, Sergiy Kalenik, Sergey Kochetov, Leonid Saliy, Vitaliy Tsyats'ko, Evgen Tsyats'ko, Oleg Shopen Copyright (c) 2021 Valentin I. Kasilov, Sergey P. Gokov, Sergiy A. Kalenik, Sergey S. Kochetov, Leonid D. Saliy, Vitaliy V. Tsyats'ko, Evgen V. Tsyats'ko, Oleg A. Shopen http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18055 Fri, 10 Dec 2021 00:00:00 +0000 Enhancing Si Solar Cells Efficiency by Adding SiO2 / TiO2 Thin Films Using Transfer Matrix Method https://periodicals.karazin.ua/eejp/article/view/17396 <p>Thin film silicon solar cells are nowadays the best choice to get electricity due to their low cost compared to the crystalline solar cells. However, thin film silicon solar cells have weak absorption of incident light. To deal with such a weakness and get better efficiency of these cells, an efficient back reflector composed of multilayer thin films (Silver, Silicon dioxide (SiO<sub>2</sub>) and Titanium dioxide (TiO<sub>2</sub>)) will be used. The transmitted light from the first silicon layer will be reflected by the next layer, and the reflected light will go back to the first silicon layer. By this way, the absorbance of the silicon solar cell can be increased by an increase in the probability of the light reflection from the SiO<sub>2</sub>, TiO<sub>2</sub> and Ag. The transfer matrix method (TMM) by Matlab program will be used to analyze the results of the reflectance, transmittance and absorbance of the thin film layer and these results can prove the efficiency of the cells by using MATLAB codes.</p> Wedad Ahmed Abdullah Garhoom, Zina Al Shadidi Copyright (c) 2021 Zina Al Shadidi http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/17396 Fri, 10 Dec 2021 00:00:00 +0000 Pressure of Electromagnetic Radiation on a Linear Vibrator https://periodicals.karazin.ua/eejp/article/view/18057 <p>Nowadays the pressure of electromagnetic radiation in the optical range is widely used in laser traps (so called optical tweezers or single-beam gradient force trap) to control the position of microparticles, biological cells and other microscopic objects. This is possible by focusing the laser radiation into the area of several micrometers in size. The intensity of the radiation in the area is sufficient to hold particles in the beam and manipulate them. We are interested to research similar possibility in the microwave range of wavelengths. However we had faced a number of difficulties in this range: the size of the focal region is much larger, the radiation intensity is less, and to control microscopic objects by means of radiation pressure very high powers are required. And we decided to consider the known effect of a very strong interaction of thin conducting fibers (metal, semiconductor, graphite) with microwave radiation. The efficiency factor of radiation pressure on such objects reaches values of several hundreds and thousands. This can be used to control objects in the form of electrically thin metal conductors by means of radiation pressure. Methods for calculating the pressure of electromagnetic radiation on an infinitely long circular cylinder are known. In this paper we propose a method for calculating the radiation pressure on a circular cylinder (vibrator), the length of which is comparable to the radiation wavelength. We have found out that when the vibrator length is close to half the wavelength, the radiation pressure efficiency factor is much larger than for an infinite cylinder. We have obtained the dependence of the radiation pressure efficiency factor on the length and diameter of an absolutely reflecting and impedance vibrator. It decreases with decreasing conductivity. An infinite cylinder at a certain value of conductivity has a maximum of the radiation pressure efficiency factor.</p> Mykola Kokodii, Sergey Berdnik, Victor Katrich, Mikhail Nesterenko, Marina Kaydash Copyright (c) 2021 Mykola G. Kokodii, Sergey L. Berdnik, Victor O. Katrich, Mikhail V. Nesterenko, Marina V. Kaydash http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18057 Fri, 10 Dec 2021 00:00:00 +0000 The Nonlinear Magnetosonic Waves in Magnetized Dense Plasma for Quantum Effects of Degenerate Electrons https://periodicals.karazin.ua/eejp/article/view/18108 <p>The nonlinear magnetosonic solitons are investigated in magnetized dense plasma for quantum effects of degenerate electrons in this research work. After reviewing the basic introduction of quantum plasma, we described the nonlinear phenomenon of magnetosonic wave. The reductive perturbation technique is employed for low frequency nonlinear magnetosonic waves in magnetized quantum plasma. In this paper, we have derived the Korteweg-de Vries (KdV) equation of magnetosonic solitons in a magnetized quantum plasma with degenerate electrons having arbitrary electron temperature. It is observed that the propagation of magnetosonic solitons in a magnetized dense plasma with the quantum effects of degenerate electrons and Bohm diffraction. The quantum or degeneracy effects become relevant in plasmas when fermi temperature and thermodynamic temperatures of degenerate electrons have same order.</p> Neelam Rani, Manikant Yadav Copyright (c) 2021 Neelam Rani, Manikant Yadav https://periodicals.karazin.ua/eejp/article/view/18108 Fri, 10 Dec 2021 00:00:00 +0000 Thermoelectric Coefficients Of Heavily Doped N-Type Silicon https://periodicals.karazin.ua/eejp/article/view/18147 <p>In this study the thermoelectric effect is investigated in terms of thermoelectric power, Figure of merit(ZT), and power factor. The calculations were carried out based on Boltzmann transport equation by taking ionized impurity scattering as a dominant mechanism for heavily doped n-type silicon at 300K with charge concentration varies from 2×10<sup>18</sup> /cm<sup>3</sup> – 20×10<sup>20</sup> /cm<sup>3</sup>. It is known that doping of materials can induce Fermi level shifts and doping can also induce changes of the transport mechanisms. The result of this study shows doping also induces changes in thermoelectric power, Figure of merit, and power factor. The magnitude of the change is different for consideration of parabolic density of states and non-parabolic modified density of states which amounts to 16.7% for thermoelectric power, from 0.059% - 84.1% for Figure of merit(ZT) in favor of non-parabolic consideration respectively. There is also a difference of 39.9% for power factor with respect to relaxation time between the two cases in favor of the parabolic consideration.</p> Mulugeta Habte Gebru Copyright (c) 2021 Mulugeta Habte Gebru http://creativecommons.org/licenses/by/4.0 https://periodicals.karazin.ua/eejp/article/view/18147 Tue, 14 Dec 2021 20:24:17 +0000