Факультет електроніки та інформаційних технологій (ЕлІТ)
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Item Computer Modelling of Metal Nanoparticles Adsorbed on Graphene(G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, 2022) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Бєсєдіна, Антоніна Анатоліївна; Беседина, Антонина Анатольевна; Biesiedina, Antonina Anatoliivna; Хоменко, Катерина Павлівна; Хоменко, Екатерина Павловна; Khomenko, Kateryna Pavlivna; Chernushchenko, R.R.The influence of deposited Al, Pd, Co, Au, Ni atoms on a single-layer graphene substrate is investigated using computer simulations. The computer modelling of spraying nanoparticles on the basis of molecular dynamics method is implemented using the NVIDIA®CUDATM technique. According to the results of model calculations, the general behaviour of the system is investigated. The experiments are performed to study the sputtering of atoms of different metals under different initial conditions of the system. Based on these sprays, the behaviour at the beginning of the interaction of the deposited atoms with the substrate is analysed. The time dependences of the lateral position of nanoparticles’ centre of mass and the substrate force throughout the experiment for different sprayed materials are compared. The behaviour of total and potential energies, temperature and momentum of the system is studied. As shown, there is a jump in total energy and temperature as well as a change in the behaviour of the momentum and the substrate force when carbon atoms of graphene are reached for all depositions.Item Atomistic modeling of formation and friction of materials with nanodimensional surfaces(Ivan Franko National University of Lviv, 2022) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Захаров, Мирослав Владиславович; Захаров, Мирослав Владиславович; Zakharov, Myroslav Vladyslavovych; Gorpinchenko, M.O.The review presents the results of modeling of the solvation of nanoparticles with deep eutectic solvents that act as stabilizers of metal nanoparticles, which provide a new platform for nanoparticle technology. It is calculated that there is a slower dynamics of solvent molecules, i.e., a slowing down of water near solutes. Such water has limited movement and cannot be organized into tetrahedral forms, in contrast to water in volume. Also, the paper describes systematic studies of the adsorption configuration, distribution density and adsorption energy of molecules Н2О, CO2, CH4, N2, C8H18 and fluorocarbons C3F8 and C5F12 on the surface of kaolinite (001). Water adsorption is initiated and occurs due to the growth of clusters around surface groups, which is mainly regulated by the interactions of hydrogen bonds. Further, the paper investigates theoretically physical and mechanical properties of nanoscale systems, in particular, nanotips, amorphous carbon monolayer and nanoparticles. It is shown that the single-layer amorphous carbon is surprisingly stable and is deformed with a high ultimate strength without the propagation of cracks from the point of failure. The sliding on amorphous polyethylene and silicon studied using the method of molecular dynamics is described. The paper also discusses the dependencies of the friction force, acting on nanoparticles, on their velocity and sizes, in particular, the contact area, the structure and the type of the material, as well as on the direction of their shear and temperature. At an angle of rotation $ 45^\circ $, the silicon friction forces reach a minimum value, which can be termed superlubricity. The molecular dynamics modeling of the surface of carbon nanotubes, chitosan, polyvinyl acetate, titanium dioxide, α-quartz and zeolite is described to solve application problems ranging from reaction control to targeted delivery and creation of new drugs. The general principles have been identified that artificial water channels made of carbon nanotubes porins must satisfy, which can serve as a basis for further experiments. The organic modification mainly forms a modifier layer by crosslinking the hydrogen bond with the substrate, the flatness of the modified layer is strongly influenced by the type and concentration of the modifier.Item Time series analysis of friction force at self-affine mode of ice surface softening(Institute for Condensed Matter Physics, 2021) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Логвиненко, Д.Т.The self-affine mode of ice softening during friction is investigated within the rheological model for viscoelastic medium approximation. The different modes of ice rubbing, determined by formation of surface liquid-like layer, are studied. The analysis of time series of friction force is carried out, namely Fourier analysis, construction of autocorrelation and difference autocorrelation functions. The spectral power law is detected for modes of crystalline ice as well as of a mixture of stable ice and metastable softening. The self-similarity and aperiodic character of corresponding time series of friction force are proved.Item Atomistic modelling of frictional anisotropy of palladium nanoparticles on graphene(Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 2021) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Захаров, Мирослав Владиславович; Захаров, Мирослав Владиславович; Zakharov, Myroslav VladyslavovychThis article is a continuation of our previous studies of the frictional anisotropy of metal nanoparticles on the surface of a graphene substrate for other temperature conditions. The friction force acting on palladium nanoparticles on a graphene sheet in various lateral directions is investigated using classical molecular dynamics modelling. Anisotropy is studied at high sliding speeds of nanoparticles consisting of 10000 atoms on the surface of graphene. The effect of incommensurability and short-range order of the contact surfaces of nanoparticles, as well as the graphene deformation lead to the absence of an expressed angular dependence of the friction force.Item Kinetics of Nanostructuring Processes of Material Surface under Influence of Laser Radiation(MDPI, 2020) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Ющенко, Ольга Володимирівна; Ющенко, Ольга Владимировна; Yushchenko, Olha Volodymyrivna; Бадалян, Анна Юріївна; Бадалян, Анна Юрьевна; Badalian, Anna YuriivnaIn this paper, further research is conducted for a synergetic model that describes the state of the material surface in the process of laser irradiation. Namely, the previously studied approach of mutually coordinated behavior of the relaxation field, concentration of relaxation zones, and field of stress is supplemented with a nonlinear term. It is shown that, using this model, we can describe the behavior of different types of systems. During the analysis, five stationary states were found which correspond to different modes of formation of relaxation areas on the surface. The regions of parameters are found at which one or another mode of the system behavior is established. Phase portraits are constructed for each mode and the kinetics of the system is described. The obtained results qualitatively coincide with the experimental data.Item Mathematical study of energy characteristics of centrifugal pumpwith single-vane impeller(Lviv Polytechnic National University, 2020) Трофименко, Павло Євгенович; Трофименко, Павел Евгеньевич; Trofymenko, Pavlo Yevhenovych; Найда, Максим Васильович; Найда, Максим Васильевич; Naida, Maksym Vasylovych; Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii VitaliiovychIn the article, the design of a centrifugal pump with a single-vane impeller is described and a theoretical calculation of such a pump is provided. The analysis of experimental investigations and the comparison with theoretical calculations are carried out. For the first time, the operating characteristics of a pump with a single-vane impeller of this type are obtained for different values of the rotation frequency.Item Інтенсивна пластична деформація: методи та математичні моделі формування наноматеріалів(Львівський національний університет імені Івана Франка, 2020) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii VitaliiovychThe paper explores methods of obtaining ultrafine-grained and nanostructural materials and corresponding theoretical models. The focus is on the methods of severe plastic deformation: examples of schemes and features of the treatment process are given. Experimental studies of obtaining nanocrystalline structures in various metals or alloys in the process of severe plastic deformation are described. These studies can be used for the synthesis of metals of different classes for the manufacture of constructions for a suitable purpose. In particular, the reasons for the formation of unstable configurations or manifestations of abnormal effects in the material properties, which are common in practice and can lead to premature destruction during operation, have been identified. Theoretical approaches to the description of the process of solids fragmentation during severe plastic deformation are reviewed. The method of nonequilibrium evolution thermodynamics is considered, which makes it possible to unambiguously establish the behavior of nonequilibrium variables during the processing of solids. The phenomenological foundations of the approach that unite the first and the second laws of thermodynamics are presented, and a model is proposed that allows describing the specifics of the process of the fragmentation and formation of a limiting (stationary) structure during the severe plastic deformation. Taking into account the two-defect approximation, the main relationships are determined in terms of effective internal energy, and the stages of the fragmentation process are described. The study shows that the Taylor relation provides a self-consistent feedback between the process of the formation of a stationary structure and the condition of its formation in the form of acting stresses. The conclusion is that there are a number of questions regarding severe plastic deformation that have not yet been fully investigated. It is these questions that should be in the main focus of future studies.Item Толерантність як професійна компетентність лікаря(ПАН; Гнозис, 2018) Хоменко, К.П.; Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Хижня, Ярослава Володимирівна; Хижня, Ярослава Владимировна; Khyzhnia, Yaroslava VolodymyrivnaСучасна медична освіта поступово відмовляється від традиційної моделі освіти з переважанням накопичення знань і переходить до особистісно-орієнтованої моделі, за якої у майбутнього лікаря формується здатність до вирішення нетипових професійних завдань, до творчого мислення, до реалізації гуманістичного принципу: лікувати хворого, а не хворобу. У зв’язку з чим особливу роль у системи медичної освіти здобуває значимість толерантність як професійна компетентність лікаря, що формується на особистісних якостях майбутніх фахівців, які здатні відповідати викликам часу, особливо в умовах бойових дій.Item Временные ряды силы трения при размягчении поверхностного слоя льда(Сумский государственный университет, 2017) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Руденко, С.В.; Хоменко, М.А.Для описания размягчения поверхности льда при трении разработана модель вязкоупругой среды, обладающей теплопроводностью [1]. Исследовано влияние аддитивных некоррелированных шумов теплового и деформационного полей на размягчение. Выведено уравнение Ланжевена и соответствующее уравнение Фоккера-Планка.Item Двухуровневая и двухмодовая кинетика фрагментации металлов при интенсивной пластической деформации(Сумский государственный университет, 2017) Хоменко, Олексій Віталійович; Хоменко, Алексей Витальевич; Khomenko, Oleksii Vitaliiovych; Трощенко, Дар`я Сергіївна; Трощенко, Дарья Сергеевна; Troshchenko, Dar`ia Serhiivna; Солонар, И.О.Обработка металлов методами интенсивной пластической деформации (ИПД) позволяет получить объемные образцы с практически беспористой субмикрокристаллической (СМК) или нанокристаллической (НК) структурой, обладающей высокими физико-механическими свойствами.