Pub Date : 2023-12-05DOI: 10.23939/jcpee2023.01.001
Roman Biliak
Graphene was first obtained at the beginning of the 21st century, and since then various methods have been developed for its synthesis. This variety is explained by the natural layered structure of graphite. A large number of methods is based on the idea of separating graphite layers. They are considered relatively cheap, productive and available in almost all laboratories. Another group of graphene synthesis methods is based on the concept of creating graphene sheets from individual carbon atoms. These methods are technologically more complex and require appropriate specialized equipment. Due to the wide range of graphene synthesis methods and their availability, researchers from all over the world can conduct experiments with this unique material in various scientific fields. This makes graphene an extremely promising object for further scientific research.
{"title":"Methods of obtaining graphene","authors":"Roman Biliak","doi":"10.23939/jcpee2023.01.001","DOIUrl":"https://doi.org/10.23939/jcpee2023.01.001","url":null,"abstract":"Graphene was first obtained at the beginning of the 21st century, and since then various methods have been developed for its synthesis. This variety is explained by the natural layered structure of graphite. A large number of methods is based on the idea of separating graphite layers. They are considered relatively cheap, productive and available in almost all laboratories. Another group of graphene synthesis methods is based on the concept of creating graphene sheets from individual carbon atoms. These methods are technologically more complex and require appropriate specialized equipment. Due to the wide range of graphene synthesis methods and their availability, researchers from all over the world can conduct experiments with this unique material in various scientific fields. This makes graphene an extremely promising object for further scientific research.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-05DOI: 10.23939/jcpee2023.01.023
M. Semeniuk, A. Kutsyk, Vasyl Tutka
Frequency-controlled electric drives are used in various industrial sectors due to the simplicity and reliability of the electric machine design, as well as the ability to provide the required control characteristics. This paper presents a mathematical model of a frequency-controlled electric drive with voltage source inverter developed by the Average Voltage in the Integration Step (AVIS) method and confirms its adequacy. A comparative analysis for the speed responce and accuracy of the model calculation by the AVIS method, compared to known methods in Matlab/Simulink and to the known results of physical experiments, demonstrated the efficiency of using the AVIS method for modeling frequency-controlled induction electric drives in phase coordinates with taking into account the actual curves of currents, flux, and torque of electronically commutated induction machines.
{"title":"A mathematical model of a frequency-controlled induction electric drive on the basis of the method of average voltages in integration step","authors":"M. Semeniuk, A. Kutsyk, Vasyl Tutka","doi":"10.23939/jcpee2023.01.023","DOIUrl":"https://doi.org/10.23939/jcpee2023.01.023","url":null,"abstract":"Frequency-controlled electric drives are used in various industrial sectors due to the simplicity and reliability of the electric machine design, as well as the ability to provide the required control characteristics. This paper presents a mathematical model of a frequency-controlled electric drive with voltage source inverter developed by the Average Voltage in the Integration Step (AVIS) method and confirms its adequacy. A comparative analysis for the speed responce and accuracy of the model calculation by the AVIS method, compared to known methods in Matlab/Simulink and to the known results of physical experiments, demonstrated the efficiency of using the AVIS method for modeling frequency-controlled induction electric drives in phase coordinates with taking into account the actual curves of currents, flux, and torque of electronically commutated induction machines.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138984940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-05DOI: 10.23939/jcpee2023.01.031
Vasyl Tchaban
So far, the fundamental laws of nature can only be obtained experimentally. Among them is Faraday's law of electromagnetic induction in mathema-tical representation as Maxwell's second law of the elec-tric field. Theoretically, it is impossible to obtain it on the basis of the laws of electrodynamics. Therefore, in the work, a bold attempt is made to theoretically obtain its analogue in the gravitational field, and then, on the basis of electromechanical analogies, to return to the electric field. What has been successfully done. But before that, there was a need to mathematically rehabili-tate the electromechanical analogies themselves, the reputation of which had suffered in the process of the reverse extension of the law from electricity to gravity under the name of gravito(electro)magnetism. Such immersion in the world of two disciplines - electricity and mechanics − is fundamental for a deeper understanding of physical processes, and at the same time for their quantitative detection.
{"title":"Theoretical justification of faraday's experimental law","authors":"Vasyl Tchaban","doi":"10.23939/jcpee2023.01.031","DOIUrl":"https://doi.org/10.23939/jcpee2023.01.031","url":null,"abstract":"So far, the fundamental laws of nature can only be obtained experimentally. Among them is Faraday's law of electromagnetic induction in mathema-tical representation as Maxwell's second law of the elec-tric field. Theoretically, it is impossible to obtain it on the basis of the laws of electrodynamics. Therefore, in the work, a bold attempt is made to theoretically obtain its analogue in the gravitational field, and then, on the basis of electromechanical analogies, to return to the electric field. What has been successfully done. But before that, there was a need to mathematically rehabili-tate the electromechanical analogies themselves, the reputation of which had suffered in the process of the reverse extension of the law from electricity to gravity under the name of gravito(electro)magnetism. Such immersion in the world of two disciplines - electricity and mechanics − is fundamental for a deeper understanding of physical processes, and at the same time for their quantitative detection.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139012104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-05DOI: 10.23939/jcpee2023.01.039
V. Yaskiv, A. Yaskiv
Development of high-quality energy supply of radio receiving devices is an urgent task. The article discusses the methods of designing high-frequency multi-channel power converters based on high-frequency magnetic amplifiers, the magnetic cores of which are made of an amorphous alloy with a rectangular hysteresis loop. Their significant advantages when powering radio receiving devices are the high quality of the output voltages and the low level of electromagnetic interference, both radiated and conductive. At the same time, they have a higher level of dynamic characteristics, reliability and efficiency while reducing their topological complexity and cost. In addition, it allows the implementation of multi-channel power converters with equivalent and independent output channels in a wide range of output powers. The paper presents the implementation of such a converter for powering radio receiving devices.
{"title":"Multi-channel switching magamp power converter for radio recieving devices","authors":"V. Yaskiv, A. Yaskiv","doi":"10.23939/jcpee2023.01.039","DOIUrl":"https://doi.org/10.23939/jcpee2023.01.039","url":null,"abstract":"Development of high-quality energy supply of radio receiving devices is an urgent task. The article discusses the methods of designing high-frequency multi-channel power converters based on high-frequency magnetic amplifiers, the magnetic cores of which are made of an amorphous alloy with a rectangular hysteresis loop. Their significant advantages when powering radio receiving devices are the high quality of the output voltages and the low level of electromagnetic interference, both radiated and conductive. At the same time, they have a higher level of dynamic characteristics, reliability and efficiency while reducing their topological complexity and cost. In addition, it allows the implementation of multi-channel power converters with equivalent and independent output channels in a wide range of output powers. The paper presents the implementation of such a converter for powering radio receiving devices.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138985050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-05DOI: 10.23939/jcpee2023.01.009
O. Malyk, I. Petrovych, H. Kenyo, Yurii Yurkevych, Yurii Vashkurak
This study examines the problem of influence of point defects on transport phenomena in CdSexTe1-x (x=0.35) crystals. For the first time, the calculation of the electronic spectrum, wave function and potential energy of the electron in CdSe0.35Te0.65 samples at a prearranged temperature was carried out. Using the supercell method, the types of point defects were established, as well as the temperature dependence of their ionization energies in the studied temperature range. The temperature dependences of the deformation constants of the optical and acoustic scattering potentials were detected and also calculated the dependences on temperature of electron scattering constants on different crystal point defects. Temperature dependences of the mobility and Hall factor of electrons were found based on the scattering models on the short-range potential.
{"title":"Electron interaction with point defects in CdSe0.35Te0.65: joining of ab initio approach with short-range principle","authors":"O. Malyk, I. Petrovych, H. Kenyo, Yurii Yurkevych, Yurii Vashkurak","doi":"10.23939/jcpee2023.01.009","DOIUrl":"https://doi.org/10.23939/jcpee2023.01.009","url":null,"abstract":"This study examines the problem of influence of point defects on transport phenomena in CdSexTe1-x (x=0.35) crystals. For the first time, the calculation of the electronic spectrum, wave function and potential energy of the electron in CdSe0.35Te0.65 samples at a prearranged temperature was carried out. Using the supercell method, the types of point defects were established, as well as the temperature dependence of their ionization energies in the studied temperature range. The temperature dependences of the deformation constants of the optical and acoustic scattering potentials were detected and also calculated the dependences on temperature of electron scattering constants on different crystal point defects. Temperature dependences of the mobility and Hall factor of electrons were found based on the scattering models on the short-range potential.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138985375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-05DOI: 10.23939/jcpee2023.01.018
Artem Melnychenko, Oleksii Shaldenko
With rapid development of machine learning and subsequently deep learning, deep neural networks achieved remarkable results in solving various tasks. However, with increasing the accuracy of trained models, new architectures of neural networks present new challenges as they require significant amount of computing power for training and inference. This paper aims to review existing approaches to reducing computational power and training time of the neural network, evaluate and improve one of existing pruning methods for a face detection model. Obtained results show that the presented method can eliminate 69% of parameters while accuracy being declined only by 1.4%, which can be further improved to 0.7% by excluding context network modules from the pruning method.
{"title":"Evaluation of a snip pruning method for a state-of-the-art face detection model","authors":"Artem Melnychenko, Oleksii Shaldenko","doi":"10.23939/jcpee2023.01.018","DOIUrl":"https://doi.org/10.23939/jcpee2023.01.018","url":null,"abstract":"With rapid development of machine learning and subsequently deep learning, deep neural networks achieved remarkable results in solving various tasks. However, with increasing the accuracy of trained models, new architectures of neural networks present new challenges as they require significant amount of computing power for training and inference. This paper aims to review existing approaches to reducing computational power and training time of the neural network, evaluate and improve one of existing pruning methods for a face detection model. Obtained results show that the presented method can eliminate 69% of parameters while accuracy being declined only by 1.4%, which can be further improved to 0.7% by excluding context network modules from the pruning method.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138985311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-05DOI: 10.23939/jcpee2023.01.035
Vasyl Tchaban, Taras Ryzhyi
A method of forming algebraic-differential equations of a nonlinear pass-through active quadripole, which connect its independent pole currents and independent polar voltages, is proposed. The difficulty of the analysis lies in the fact that some of both internal and external unknowns may be under the symbol of differentiation. The common differential equations of the system of internal and external currents and voltages act as starting information for this formation. The method is demonstrated on two cases of the formation of corresponding algebraic-differential equations of systems as formed by nonlinear two-port elements. The analysis is significantly simplified in the case of internal D-degeneracies of the system or purely resistive circuits.
{"title":"Algebraic-differential equations of a nonlinear pass-through quadripole","authors":"Vasyl Tchaban, Taras Ryzhyi","doi":"10.23939/jcpee2023.01.035","DOIUrl":"https://doi.org/10.23939/jcpee2023.01.035","url":null,"abstract":"A method of forming algebraic-differential equations of a nonlinear pass-through active quadripole, which connect its independent pole currents and independent polar voltages, is proposed. The difficulty of the analysis lies in the fact that some of both internal and external unknowns may be under the symbol of differentiation. The common differential equations of the system of internal and external currents and voltages act as starting information for this formation. The method is demonstrated on two cases of the formation of corresponding algebraic-differential equations of systems as formed by nonlinear two-port elements. The analysis is significantly simplified in the case of internal D-degeneracies of the system or purely resistive circuits.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138985288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-06DOI: 10.23939/jcpee2022.02.040
D. Sugak, U. Yakhnevych, O.A. Buryi, I. Syvorotka, S. Hurskyy
The article deals with research into the processes of diffusion and drift of copper ions in a lithium niobate crystal after annealing in the presence of a copper film deposited on the crystal surface. For this purpose, there are chosen temperatures T = 600, 650, 700, 750 and 800°C, with the duration of high-temperature annealing being 6 hours for each sample. The optical absorption spectra of the samples are recorded in the direction perpendicular to the direction of diffusion at different distances from the edge of the crystal. Absorption bands of Cu+ (400 nm) and Cu2+ (1000 nm) ions are observed in all the samples annealed. The intensity of the bands varies depending on the annealing temperature and the distance from the diffusion source. Concentrations of copper ions are calculated using the Smakula–Dexter formula. Depth dependences of the Cu ions concentration are approximated within the framework of the model, taking into account both diffusion and drift of Cu ions. Experimental spatial distributions of copper ion concentrations are well approximated by theoretical curves calculated within the framework of the mathematical model of diffusion. The diffusion coefficients determined from the approximations are well-agreed with the available data from the literature.
{"title":"Optical study and simulation of diffusion of copper ions in the linbo3 crystal","authors":"D. Sugak, U. Yakhnevych, O.A. Buryi, I. Syvorotka, S. Hurskyy","doi":"10.23939/jcpee2022.02.040","DOIUrl":"https://doi.org/10.23939/jcpee2022.02.040","url":null,"abstract":"The article deals with research into the processes of diffusion and drift of copper ions in a lithium niobate crystal after annealing in the presence of a copper film deposited on the crystal surface. For this purpose, there are chosen temperatures T = 600, 650, 700, 750 and 800°C, with the duration of high-temperature annealing being 6 hours for each sample. The optical absorption spectra of the samples are recorded in the direction perpendicular to the direction of diffusion at different distances from the edge of the crystal. Absorption bands of Cu+ (400 nm) and Cu2+ (1000 nm) ions are observed in all the samples annealed. The intensity of the bands varies depending on the annealing temperature and the distance from the diffusion source. Concentrations of copper ions are calculated using the Smakula–Dexter formula. Depth dependences of the Cu ions concentration are approximated within the framework of the model, taking into account both diffusion and drift of Cu ions. Experimental spatial distributions of copper ion concentrations are well approximated by theoretical curves calculated within the framework of the mathematical model of diffusion. The diffusion coefficients determined from the approximations are well-agreed with the available data from the literature.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131571289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-06DOI: 10.23939/jcpee2022.02.026
A. Druzhynin, O. Kutrakov, S. Nichkalo
At the stage of designing, the prototype of a multifunctional computer-aided informational measuring system with wireless data transferring with the use of various sensors of physical values was developed, and experimental investigations of such a system for revealing the possibilities of correct work with the sensors industrially produced, as well as sensors and converters of physical quantities developed at the Laboratory of sensor electronics of the Department of Semiconductor Electronics of Lviv Polytechnic National University as a part of a current research project were carried out
{"title":"Informational measuring system with wireless data transferring for sensors of physical values","authors":"A. Druzhynin, O. Kutrakov, S. Nichkalo","doi":"10.23939/jcpee2022.02.026","DOIUrl":"https://doi.org/10.23939/jcpee2022.02.026","url":null,"abstract":"At the stage of designing, the prototype of a multifunctional computer-aided informational measuring system with wireless data transferring with the use of various sensors of physical values was developed, and experimental investigations of such a system for revealing the possibilities of correct work with the sensors industrially produced, as well as sensors and converters of physical quantities developed at the Laboratory of sensor electronics of the Department of Semiconductor Electronics of Lviv Polytechnic National University as a part of a current research project were carried out","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129376142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-06DOI: 10.23939/jcpee2022.02.022
Oleksii Pysarchuk, Yuri Mironov
This paper proposes an approach to the detection and extraction of specific features in an ideogram image. Ideogram is a depiction of a healthy chromosome used in a karyotyping process - a procedure designed to diagnose chromosomal abnormalities. Extraction of ideogram features is a part of a general algorithm for the detection of chromosomal abnormlities. According to the general algorithm, both chromosomes and ideograms have to be parsed and converted into a single data format for further comparison. The image of the ideogram is the input data for the algorithm of the extraction of ideogram features, which is proposed in this paper. The output is a data structure containing ideogram properties. A software prototype has been developed to verify the algorithm efficiency.
{"title":"Extraction of ideogram features for diagnosing chromosomal abnormalities","authors":"Oleksii Pysarchuk, Yuri Mironov","doi":"10.23939/jcpee2022.02.022","DOIUrl":"https://doi.org/10.23939/jcpee2022.02.022","url":null,"abstract":"This paper proposes an approach to the detection and extraction of specific features in an ideogram image. Ideogram is a depiction of a healthy chromosome used in a karyotyping process - a procedure designed to diagnose chromosomal abnormalities. Extraction of ideogram features is a part of a general algorithm for the detection of chromosomal abnormlities. According to the general algorithm, both chromosomes and ideograms have to be parsed and converted into a single data format for further comparison. The image of the ideogram is the input data for the algorithm of the extraction of ideogram features, which is proposed in this paper. The output is a data structure containing ideogram properties. A software prototype has been developed to verify the algorithm efficiency.","PeriodicalId":325908,"journal":{"name":"Computational Problems of Electrical Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120818540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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