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 the 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,&nbsp;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&nbsp;specialized editions of Ukraine (<strong>category “A”, specialty: 104, 105</strong>), which can be published results of dissertations for the Ph.D. and Dr.Sci.&nbsp;degree in physical and mathematical sciences.</p> <p>The Journal is 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> V.N. Karazin Kharkiv National University en-US East European Journal of Physics 2312-4334 <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> How the Limit Values Work https://periodicals.karazin.ua/eejp/article/view/16915 <p><sup></sup></p> <p>The efficiency of limiting quantities as a tool for describing physics at various spatio-temporal scales is shown. Due to its universality, limit values allow us to establish relationships between, at first glance, distant from each other's characteristics. The article discusses specific examples of the use of limit values to establish such relationships between quantities at different scales. Based on the principle of reaching the limiting values on the event horizons, a connection was obtained between the Planck values and the values of the Universe. The resulting relation can be attributed to relations of the Dirac type - the coincidence of large numbers that emerged from empirical observations. In the article, the relationships between large numbers of the Dirac type are established proceeding, in a certain sense, from physical principles - the existence of limiting values. It is shown that this ratio is observed throughout the evolution of the Universe. An alternative way of solving the problem of the cosmological constant using limiting values and its relation to the minimum spatial scale is discussed. In addition, a one-parameter family of masses was introduced, including the mass of the Universe, the Planck mass and the mass of the graviton, which also establish relationships between quantities differing by 120 orders of magnitude. It is shown that entropic forces also obey the same universal limiting constraints as ordinary forces. Thus, the existence of limiting values extends to informational limitations in the Universe. It is fundamentally important that on any event horizon, regardless of its scale (i.e., its gravitational radius), the universal value of limit force&nbsp;c<sup>4</sup>/4G is realized. This allows you to relate the characteristics of the Universe related to various stages of its evolution.</p> <p></p> Yuri L. Bolotin Vladimir V. Yanovsky ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-28 2021-02-28 1 5 12 10.26565/2312-4334-2021-1-01 Modelling of Nonlinear Thermodiffusion for a Spherically Symmetric Case https://periodicals.karazin.ua/eejp/article/view/16460 <p>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.&nbsp;J.&nbsp;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<em>.</em></p> Sigita Turskiene Arvydas J. Janavičius ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-17 2021-02-17 1 13 19 10.26565/2312-4334-2021-1-02 Studies of Dosimetry Protocols for Accelerated Photons and Electrons Delivered from Medical Linear Accelerator https://periodicals.karazin.ua/eejp/article/view/16920 <p>We focus on the comparative study of dosimetry protocols in radiotherapy for accelerated photon and electron delivered from medical linear accelerator (LINAC). In this study, a comparison between the protocols (TRS 398, DIN 6800-2 and TG 51) for both the electron and photon delivered from Clinac 2300CD and Clinac DHX 3186 were performed. We used photon beams with energies of 6 and 15 MV and electron beams of 4, 6, 9, 12, 15 and 18 MeV for both Medical Linac. In case of Clinac the maximum deviations for the relative dose at D<sub>max</sub> for the photon beam (15 MV) among the protocols was observed to be 1.18% between TRS-398 and TG-51, 1.56% between TG-51 and DIN 6800-2; and 0.41% between TRS-398 and DIN 6800-2. Conversely, these deviations were 3.67% between TRS-398 and TG-51, 3.92% between TG-51 and DIN 6800-2 for 4 MeV and 0.95% between TRS-398 and DIN 6800-2 in the case of Clinac 2300 CD for the PTW Markus and Exradin A10. For the measurement of the maximum absorbed dose depth to water using three protocols, the maximum deviations were observed between TRS 398 and TG-51 as well as TG51 and DIN 6800-2.</p> AKM Moinul Haque Meaze Santunu Purohit Md. Shakilur Rahman Abdus Sattar SM Enamul Kabir Md. Kawchar Ahmed Patwary Kamrunnahar Kali Md. Jubayer Rahman Akhand ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-03-01 2021-03-01 1 20 26 10.26565/2312-4334-2021-1-03 Investigation on Electronic and Thermoelectric Properties of (P, As, Sb) Doped ZrCoBi https://periodicals.karazin.ua/eejp/article/view/16916 <p>Since the last decade, the half-Heusler (HH) compounds have taken an important place in the field of the condensed matter physics research. The multiplicity of substitutions of transition elements at the crystallographic sites X, Y and (III-V) elements at the Z sites, gives to the HH alloys a multitudes of remarkable properties. In the present study, we examined the structural, electronic and thermoelectric properties of ZrCoBi<sub>0.75</sub>Z<sub>0.25 </sub>(Z = P, As, Sb) using density functional theory (DFT). The computations have been done parallel to the full potential linearized augmented plane wave (FP-LAPW) method as implemented in the WIEN2k code. The thermoelectrically properties were predicted via the semi-classical Boltzmann transport theory, as performed in Boltztrap code. The obtained results for the band structure and densities of states confirm the semiconductor (SC) nature of the three compounds with an indirect band gap, which is around 1eV. The main thermoelectric parameters such as Seebeck coefficient, thermal conductivity, electrical conductivity and figure of merit were estimated for temperatures ranging from zero to 1200K. The positive values of Seebeck coefficient (S) confirm that the ZrCoBi<sub>0.75</sub>Z<sub>0.25 </sub>(x = 0 and 0.25) are a p-type SC. At the ambient temperature, ZrCoBi<sub>0.75</sub>P<sub>0.25 </sub>exhibit the large S value of 289 µV/K, which constitutes an improvement of 22% than the undoped ZrCoBi, and show also a reduction of 54% in thermal conductivity (κ/τ). The undoped ZrCoBi has the lowest ZT value at all temperatures and by substituting bismuth atom by one of the sp elements (P, As, Sb), a simultaneous improvement in κ/τ and S have led to maximum figure of merit (ZT) values of about 0.84 obtained at 1200 K for the three-doped compounds.</p> Djelti Radouan Besbes Anissa Bestani Benaouda ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-28 2021-02-28 1 27 33 10.26565/2312-4334-2021-1-04 Electrical and Photoelectric Properties of Heterojunctions MoOx/n-Cd1-xZnxTe https://periodicals.karazin.ua/eejp/article/view/16461 <p>The paper presents the results of studies of the optical and electrical properties of МоO<sub>x</sub>/n-Cd<sub>1-х</sub>Zn<sub>х</sub>Te semiconductor heterojunctions made by depositing MoO<sub>x</sub> films on a pre-polished surface of n-Cd<sub>1-х</sub>Zn<sub>х</sub>Te plates (5 × 5 × 0.7 mm<sup>3</sup>) in a universal vacuum installation Leybold - Heraeus L560 using reactive magnetron sputtering of a pure Mo target. Such studies are of great importance for the further development of highly efficient devices based on heterojunctions for electronics and optoelectronics. The fabricated МоO<sub>x</sub>/n‑Cd<sub>1‑х</sub>Zn<sub>х</sub>Te heterojunctions have a large potential barrier height at room temperature (φ<sub>0 </sub>= 1.15 &nbsp;eV), which significantly exceeds the analogous parameter for the МоO<sub>x</sub>/n-CdTe heterojunction (φ<sub>0</sub> = 0.85 eV). The temperature coefficient of the change in the height of the potential barrier was experimentally determined to be <em>d(φ<sub>0</sub>)/dT</em> = -8.7·10<sup>-3</sup> eV K, this parameter is four times greater than the temperature coefficient of change in the height of the potential barrier for MoO<sub>x</sub>/n-CdTe heterostructures. The greater value of the potential barrier height of the МоO<sub>x</sub>/n-Cd<sub>1-х</sub>Zn<sub>х</sub>Te heterojunction is due to the formation of an electric dipole at the heterointerface due to an increase in the concentration of surface states in comparison with MoO<sub>x</sub>/n-CdTe heterostructures, and this is obviously associated with the presence of zinc atoms in the space charge region and at the metallurgical boundary section of the heteroboundary. In МоO<sub>x</sub>/n‑Cd<sub>1-х</sub>Zn<sub>х</sub>Te heterojunctions, the dominant mechanisms of current transfer are generation-recombination and tunneling-recombination with the participation of surface states, tunneling with forward bias, and tunneling with reverse bias. It was found that МоO<sub>x</sub>/n-Cd<sub>1-х</sub>Zn<sub>х</sub>Te heterojunctions, which have the following photoelectric parameters: open circuit voltage V<sub>oc</sub> = 0.3 V, short circuit current I<sub>sc</sub> = 1.2 mA/cm<sup>2</sup>, and fill factor FF = 0.33 at an illumination intensity of 80 mW/cm<sup>2</sup> are promising for the manufacture of detectors of various types of radiation. The measured and investigated impedance of the МоO<sub>x</sub>/n-Cd<sub>1-х</sub>Zn<sub>х</sub>Te heterojunction at various reverse biases, which made it possible to determine the distribution of the density of surface states and the characteristic time of their charge-exchange, which decrease with increasing reverse bias.</p> Mykhailo M. Solovan Andrii I. Mostovyi Hryhorii P. Parkhomenko Viktor V. Brus Pavlo D. Maryanchuk ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-17 2021-02-17 1 34 42 10.26565/2312-4334-2021-1-05 Elastic Properties of Alloy ZE10 Sheets Evaluation by Kerns Texture Parameters https://periodicals.karazin.ua/eejp/article/view/16552 <p>The ZE10 magnesium alloy with the rare-earth metal additives, which contribute to a better forming of the alloy, was used as studied material. The ZE10 magnesium alloy with the rare-earth metal additives, which contribute to a better forming of the alloy, was used as studied material. Sheet material is usually straightened on roller levelers to relieve residual stresses and improve flatness. The metal is subjected to alternating deformation by bending when straightening. The changes in the structure, crystallographic texture and, as a result, physical and mechanical properties occur in the metal are often not taken into account in the future. The elastic modulus is an important parameter, for example, in the production of products using bending. In this work, the elastic modulus of sheets of magnesium alloy ZE10 was estimated in three main directions. A starting sheet was obtained by extruding an ingot, then rolling in the longitudinal direction and then rolling with a change in direction by 90° after each pass in combination with heating to 350°C. The original sheets were subsequently subjected to alternate folding. Evaluations were made of the elastic modulus of the original sheet, as well as the sheets after 0.5, 1.0, 3.0 and 5.0 alternating bending cycles. To estimate the elastic modulus, we used the Kearns texture parameters , which we calculated from the inverse pole figures, as well as the elastic constants of the single crystal of the ZE10 alloy found by us. The maximum deviation of the calculated and experimental values of the elastic modulus did not exceed 5.2%. Strong correlations and quadratic regression equations have been established between the values of the elastic modulus, mechanical characteristics (tensile strength, yield stress, elongation), on the one hand, and the above-mentioned parameters of the Kerns texture, on the other hand. The approximation reliability coefficients are 0.76 - 0.99.</p> Valentin Valentinovich Usov Natalia shkatulyak Elena Savchuk Nadezhda Rybak ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-19 2021-02-19 1 43 49 10.26565/2312-4334-2021-1-06 Surface Purity Effect on Irregularities of Changes in Deformation Texture of Zr-2.5% Nb Alloy https://periodicals.karazin.ua/eejp/article/view/16923 <p>This work is a continuation of a series of works on the study of regularities and structural mechanisms of changes in characteristics of crystallographic texture during cold deformation of plates made of Zr2.5%Nb alloy. Effects of influence of surface cleanliness of the plates on the textural regularities during their rolling were investigated. For this, longitudinal fragments of the tube Æ15.0´1.5&nbsp;mm² were used, flattened, annealed at 580°C in a vacuum of 1.5...3.0 Pa and rolled along the axis of the original tube with various degrees deformation up to 56%, which is likened to longitudinal rolling of plates. Techniques of maximally uniform straightening of tube fragments were used. An analysis of the results of studies of textural changes during cross rolling of plates, straightened from rings of the same tube and pretreated under similar conditions, is also carried out. To analyze the results, the method of inverse pole figures was used, which, in these studies, is distinguished by the possibility of achieving satisfactory accuracy in calculating the integral characteristics of texture. On this basis, the Kearns textural coefficient was calculated along the normal to the plates’ plane. Corrections were introduced for texture dissimilarity along the thickness of the plates, which is caused by the unbending of the preliminary blanks. Additionally, the analysis of texture distributions was carried out using original techniques. According to the results obtained – as a result of X-ray measuring from the plates’ surface – oscillations of the course of changes in the texture coefficient were revealed. This is associated with an alternating process of relaxation of residual stresses during deformation. It has been established that this effect is initiated from the near-surface regions, is associated with a near-surface impurity, and in some cases can penetrate to a considerable depth of the plates. The twinning nature of such regularities is confirmed and active systems of twins are noted.</p> Dmitry G. Malykhin Kostiantyn V. Kovtun Tetiana S. Yurkova Viktor M. Grytsyna Gennadiy P. Kovtun Iryna G. Tantsura Volodymyr D. Virych Yuri V. Gorbenko Victor M. Voyevodin ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-03-01 2021-03-01 1 50 54 10.26565/2312-4334-2021-1-07 Zone Recrystallization of Zirconium and Hafnium https://periodicals.karazin.ua/eejp/article/view/16924 <p>The work studied the possibility of obtaining of the high-purity samples of zirconium and hafnium by the method of zone recrystallization of round rods with electron-beam heating in a vacuum of 1∙10<sup>-4</sup> Pa. Some meltings were carried out in a constant electric field with the variability of its connection. It is shown that the simultaneous passage of several refining processes (evaporation of highly volatile metallic impurities, zone recrystallization with directional displacement of impurities to the end of the sample, electrotransport) made it possible to efficient refining of zirconium both from metallic impurities and from interstitial impurities. The best degree of purification was achieved when zone melting carrying out in an electric field directed opposite to the zone movement. In this case, the displacement of interstitial impurity ions coincided with the direction of movement of the liquid zone. Samples of zirconium with a purity of 99.89 wt. % were obtained (the concentration of aluminum was reduced by 5, iron - 11, copper - 45, chromium - 75, silicon - 10, titanium - 2.5, oxygen - 3.3, nitrogen - 3, carbon - 2 times). The hafnium samples refined by the zone recrystallization method were characterized by a purity of 99.85 wt. %. The concentrations of both all metal impurities and interstitial impurities were significantly reduced (concentration in wt% oxygen was 0.011, carbon - 0.0018, nitrogen - 5∙10<sup>-5</sup>). A&nbsp;study of gas evolution from samples of iodide hafnium and refined hafnium was carried out. It was found that the maximum gas release peak fell on the temperature range of 500 ... 550 °C. The use of an integrated approach, including high-temperature heating, stages of zone melting at different rates, and thermal cycling in the range of the polymorphic transformation temperature, made it possible to obtain single-crystal hafnium samples. According to X-ray diffraction data, the parameters of the hafnium crystal lattice were determined: <em>а</em>&nbsp;=&nbsp;(0.31950&nbsp;±&nbsp;5·10<sup>-5</sup>)&nbsp;nm and <em>с</em><em>&nbsp;</em>=&nbsp;(0.50542&nbsp;±&nbsp;5·10<sup>-5</sup>)&nbsp;nm (at 298&nbsp;K), which corresponds to the density <em>ρ</em>&nbsp;=&nbsp;13.263&nbsp;g/cm<sup>3</sup> and axial ratio <em>с</em>/<em>a</em> = 1.5819.</p> Оleh Е. Коzhevnikov Mykola M. Pylypenko Maryna F. Коzhevnikova ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-03-01 2021-03-01 1 55 62 10.26565/2312-4334-2021-1-08 Structure and Properties of ZnSnP2 With the Application in Photovoltaic Devices by Using CdS and ZnTe Buffer Layers https://periodicals.karazin.ua/eejp/article/view/16350 <p>Ab initio calculations have been performed by the linearized augmented plane wave (LAPW) method as implemented in the WIEN2K code within the density functional theory to obtain the structural, electronic and optical properties of ZnSnP<sub>2 </sub>in the body centered tetragonal (BCT) phase. The six elastic constants (C<sub>11</sub>, C<sub>12</sub>, C<sub>13</sub>, C<sub>33</sub>, C<sub>44</sub> and C<sub>66</sub>) and mechanical parameters have been presented and compared with the available experimental data. The thermodynamic calculations within the quasi-harmonic approximation is used to give an accurate description of the pressure-temperature dependence of the thermal-expansion coefficient, bulk modulus, specific heat, Debye temperature, entropy Grüneisen parameters. Based on the semi-empirical relation, we have determined the hardness of the material; which attributed to different covalent bonding strengths. Further, ZnSnP<sub>2 </sub>solar cell devices have been modeled; device physics and performance parameters have analyzed for ZnTe and CdS buffer layers. Simulation results for ZnSnP<sub>2</sub> thin layer solar cell show the maximum efficiency (22.9%) with ZnTe as the buffer layer. Most of the investigated parameters are reported for the first time.</p> Neeraj Neeraj Ajay Singh Verma ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-13 2021-02-13 1 63 79 10.26565/2312-4334-2021-1-09 Optoelectronic Properties of Ternary Tetrahedral Semiconductors https://periodicals.karazin.ua/eejp/article/view/16464 <p>The dielectric interpretation of crystal ionicity evolved by Phillips and Van Vechten (P.V.V) has been utilized to evaluate various ground state properties for broad range of semiconductors and insulators. Although, the relevance of P.V.V dielectric theory has been restricted to only simple A<sup>N</sup>B<sup>8-N</sup> structured compounds, which have a particular bond. Levine has broadened P.V.V. theory of ionicity to multiple bond and complex crystals and evaluated many bond parameters for ternary tetrahedral semiconductors. Some other researchers have extended Levine’s work with a concept of ionic charge product and nearest neighbour distance to binary and ternary tetrahedral crystals to evaluate the ground state properties. In this paper, a new hypothesis of average atomic number of the elements in a compound has been used to understand the some electronic and optical properties such as ionic gap (E<sub>c</sub>), average energy gap (E<sub>g</sub>), crystal ionicity (f<sub>i</sub>), electronic susceptibility (χ), and dielectric constant (ϵ) of ternary tetrahedral (A<sup>II</sup>B<sup>IV</sup><sup>&nbsp;</sup>and A<sup>I</sup>B<sup>III</sup>) semiconductors. A reasonably acceptable agreement has been noticed between our evaluated values and other researchers reported values.</p> Rajesh C. Gupta Ajay Singh Verma Khushvant Singh ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-19 2021-02-19 1 80 88 10.26565/2312-4334-2021-1-10 Empirical Relation for Electronic and Optical Properties of Binary Tetrahedral Semiconductors https://periodicals.karazin.ua/eejp/article/view/16351 <p>The concept of ionicity has been developed by Phillips and Van Vechten from the dielectric analysis of the semiconductors and insulators to evaluate various bond parameters of binary tetrahedral (A<sup>II</sup>B<sup>VI</sup> and A<sup>III</sup>B<sup>V</sup>) semiconductors. In this paper, an advance hypothesis of average atomic number of the elements in a compound has been used to evaluate intrinsic electronic and optical parameters such as ionic gap (E<sub>c</sub>), average energy gap (E<sub>g</sub>), crystal ionicity (f<sub>i</sub>) and dielectric constant (ϵ) of binary tetrahedral semiconductors.</p> Ajay Singh Verma Rajesh C. Gupta Khushvant Singh ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-02-20 2021-02-20 1 89 92 10.26565/2312-4334-2021-1-11 Study of Structural and Electronic Properties of Intercalated Transition Metal Dichalcogenides Compound MTiS2 (M = Cr, Mn, Fe) by Density Functional Theory https://periodicals.karazin.ua/eejp/article/view/16925 <p>In the present work, we have studied intercalated Transition Metal Dichalcogenides (TMDC) MTiS<sub>2</sub> compounds (M = Cr, Mn, Fe) by Density Functional Theory (DFT) with Generalized Gradient Approximation (GGA). We have computed the structural and electronic properties by using first principle method in QUANTUM ESPRESSO computational code with an ultra-soft pseudopotential. A guest 3d transition metal M (viz; Cr, Mn, Fe) can be easily intercalated in pure transition metal dichalcogenides compound like TiS<sub>2</sub>. In the present work, the structural optimization, electronic properties like the energy band structure, density of states (DoS), partial or projected density of states (PDoS) and total density of states (TDoS) are reported. The energy band structure of MTiS<sub>2</sub> compound has been found overlapping energy bands in the Fermi region. We conclude that the TiS<sub>2</sub> intercalated compound has a small band gap while the doped compound with guest 3d-atom has metallic behavior as shown form its overlapped band structure.</p> Vandana B. Parmar Aditya M. Vora ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-03-01 2021-03-01 1 93 98 10.26565/2312-4334-2021-1-12 Plasma Chemical Method of Decreasing the Ethylene Impurities in the Air https://periodicals.karazin.ua/eejp/article/view/16919 <p>The efficiency of ethylene impurities decomposition in barrierless plasma-chemical system during artificial injection into the air of a sea container has been studied. The experimental study was performed at the air temperature 5<sup>o</sup>C in container volume 65&nbsp;m<sup>3</sup>. The initial level of ozone in the air was 100 ppb. This concentration is below concentration which audible to humans. It has been established that the use of a carbon filter after a plasma chemical system allows to maintain the ozone content in the air at an acceptable level (in terms of human health and food storage). During 24 hours the ethylene concentration increases until an equilibrium concentration is reached. After the plasma chemical rector was switched on, the ethylene concentration in the container began to decrease due to decomposition in the low-temperature plasma and interaction with ozone until new equilibrium concentration was reached. The ozone concentration after plasma chemical reactor was switched to begin increased. After 1 hour, the new minimum equilibrium ethylene and ozone concentration was established. The decrease in concentration occurred exponentially and reached a new equilibrium concentration above zero, which is consistent with the theory. The increase in ozone concentration occurs by about 20-25%. It has been shown that using plasma chemical system based on barrierless plasma chemical reactors can reduce the ethylene concentration by up to 10 times, even for low concentrations of ethylene in the air.</p> Leonid M. Zavada Dmytro V. Kudin ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-03-01 2021-03-01 1 99 103 10.26565/2312-4334-2021-1-13 Oleksiy Hryhorovych Sytenko: Manager, Scientist, Citizen https://periodicals.karazin.ua/eejp/article/view/16926 <p>Академік НАН України Олексій Григорович Ситенко (наукова школа академіка О.І. Ахієзера) збагатив теоретичну ядерну фізику і теорію плазми відкриттям низки ефектів, що нині носять його ім’я. Підґрунтям фундації його наукової школи були 50-ті роки минулого століття, коли він працював у Харківському фізико-технічному інституті та викладав у Харківському державному університеті. Подальшого розвитку його наукова школа набула в Києві. завдячуючи спогадам його учнів, колег та родини академіка О.Г. Ситенка,&nbsp; викладено життєпис ученого раніш не оприлюдненими фактами про його родовід, дитячі й юнацькі роки, а також реконструйовано витоки його наукових уподобань, чинники формування наукового світогляду, напрями наукової, педагогічної і науково-організаційної діяльності, пріоритетні наукові результати.</p> Alla Tanshyna ##submission.copyrightStatement## http://creativecommons.org/licenses/by/4.0 2021-03-01 2021-03-01 1 104 109 10.26565/2312-4334-2021-1-14