Pub Date : 2023-12-02DOI: 10.26565/2312-4334-2023-4-43
Dudekula Dastagiri Babu, S. Venkateswarlu, E. K. Reddy
Numerical model is conducted to investigate the behavior of an incompressible Maxwell nanofluid model flow on a convectively stretched surface, considering the effects of thermophoresis and an inclined magnetic field. The system, originally formulated as a set of partial differential equations, is transformed into a system of ordinary differential equations using similarity transformations. The resulting equations are solved using the Runge-Kutta-Fehlberg method in conjunction with the shooting technique. The obtained physical parameters from the derived system are presented and discussed through graphical representations. The numerical process is assessed by comparing the results with existing literature under various limiting scenarios, demonstrating a high level of proficiency. The key findings of this study indicate that the velocity field decreases as the fluid parameters increase, while the fluid temperature diminishes accordingly. Additionally, the heat transfer rate decreases with increasing fluid and thermophoresis parameters, but it increases with Biot and Prandtl numbers.
{"title":"Numerical Investigation of Thermophoresis and Activation Energy Effects on Maxwell Nano Fluid Over an Inclined Magnetic Field Applied to a Disk","authors":"Dudekula Dastagiri Babu, S. Venkateswarlu, E. K. Reddy","doi":"10.26565/2312-4334-2023-4-43","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-43","url":null,"abstract":"Numerical model is conducted to investigate the behavior of an incompressible Maxwell nanofluid model flow on a convectively stretched surface, considering the effects of thermophoresis and an inclined magnetic field. The system, originally formulated as a set of partial differential equations, is transformed into a system of ordinary differential equations using similarity transformations. The resulting equations are solved using the Runge-Kutta-Fehlberg method in conjunction with the shooting technique. The obtained physical parameters from the derived system are presented and discussed through graphical representations. The numerical process is assessed by comparing the results with existing literature under various limiting scenarios, demonstrating a high level of proficiency. The key findings of this study indicate that the velocity field decreases as the fluid parameters increase, while the fluid temperature diminishes accordingly. Additionally, the heat transfer rate decreases with increasing fluid and thermophoresis parameters, but it increases with Biot and Prandtl numbers.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187456","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-18
Khodjakbar S. Daliev, Zavkiddin E. Bahronkulov, Jonibek J. Hamdamov
This article discusses the electrical properties of silicon doped with rare earth elements (REE). Atoms of rare earth elements (REE) diffused onto the surface of the silicon substrate. To measure the electrical parameters, samples of n-Si, n-Si, n-Si and n-Si were prepared and their electrical properties were determined using the Hall effect, four-probe and thermal probe methods. The studies were carried out in the temperature range 77÷300 K. The samples were ohmically contacted using a mixture of 1% Sb + 99% Au for measurement on the HMS500 instrument. The specific resistance of the samples in layers, the concentration of charge carriers, and the mobility of the samples were also studied by the magnetoresistance method. The electrical parameters of the samples were measured on an Ecopia Hall effect measuring system (HMS5000).
本文讨论了掺杂稀土元素 (REE) 的硅的电气特性。稀土元素原子扩散到硅衬底表面。为了测量其电气参数，制备了正硅样品、正硅样品、正硅样品和正硅样品，并使用霍尔效应法、四探针法和热探针法测定了它们的电气特性。研究是在 77÷300 K 的温度范围内进行的。样品使用 1% Sb + 99% Au 的混合物进行欧姆接触，在 HMS500 仪器上进行测量。此外，还利用磁阻法研究了样品层间的比电阻、电荷载流子浓度和样品的迁移率。样品的电气参数是在 Ecopia 霍尔效应测量系统 (HMS5000) 上测量的。
{"title":"Investigation of the Magnetic Properties of Silicon Doped with Rare-Earth Elements","authors":"Khodjakbar S. Daliev, Zavkiddin E. Bahronkulov, Jonibek J. Hamdamov","doi":"10.26565/2312-4334-2023-4-18","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-18","url":null,"abstract":"This article discusses the electrical properties of silicon doped with rare earth elements (REE). Atoms of rare earth elements (REE) diffused onto the surface of the silicon substrate. To measure the electrical parameters, samples of n-Si, n-Si, n-Si and n-Si were prepared and their electrical properties were determined using the Hall effect, four-probe and thermal probe methods. The studies were carried out in the temperature range 77÷300 K. The samples were ohmically contacted using a mixture of 1% Sb + 99% Au for measurement on the HMS500 instrument. The specific resistance of the samples in layers, the concentration of charge carriers, and the mobility of the samples were also studied by the magnetoresistance method. The electrical parameters of the samples were measured on an Ecopia Hall effect measuring system (HMS5000).","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187470","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-26
Muhammad R. Ramadhan, Salwa A. Khansa, Qoriana Zulindra, Dian P. Handayani, Nina A. Wardani, Fahmia Astuti
Due to the necessity of reducing the reliance on fossil fuels, several systems are considered to be alternative and/or additional support for the existing battery material. In this report, structural and electronic properties of aluminium oxide (Al2O3) and aluminium sulfide (Al2S3) with hexagonal symmetry (α-phase), are investigated by utilizing density functional theory technique based on r++SCAN functional. The calculated lattice parameter and insulating gap for both systems are well matched with previous experimental studies and display higher accuracy compared to the results from local density approximation (LDA) and generalized gradient approximation (GGA) studies. The calculated insulating gap values are 10.3 eV and 4.1 eV for α-Al2O3 and α-Al2S3 respectively. For α-Al2O3 system, we observed hybridized s-p-d orbital of Al-O in the conduction states, consistent with the interpretation of past X-ray Absorption Near Edge Structure (XANES) data. Finally, the bulk and young modulus for α-Al2O3 are determined to be 251 GPa and 423 GPa which is very close to the known experimental values of 280 GPa and 451 GPa.
{"title":"Electronic Structure Calculation of α-Al2X3 System (X = O, S) Based on R++Scan Functional","authors":"Muhammad R. Ramadhan, Salwa A. Khansa, Qoriana Zulindra, Dian P. Handayani, Nina A. Wardani, Fahmia Astuti","doi":"10.26565/2312-4334-2023-4-26","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-26","url":null,"abstract":"Due to the necessity of reducing the reliance on fossil fuels, several systems are considered to be alternative and/or additional support for the existing battery material. In this report, structural and electronic properties of aluminium oxide (Al2O3) and aluminium sulfide (Al2S3) with hexagonal symmetry (α-phase), are investigated by utilizing density functional theory technique based on r++SCAN functional. The calculated lattice parameter and insulating gap for both systems are well matched with previous experimental studies and display higher accuracy compared to the results from local density approximation (LDA) and generalized gradient approximation (GGA) studies. The calculated insulating gap values are 10.3 eV and 4.1 eV for α-Al2O3 and α-Al2S3 respectively. For α-Al2O3 system, we observed hybridized s-p-d orbital of Al-O in the conduction states, consistent with the interpretation of past X-ray Absorption Near Edge Structure (XANES) data. Finally, the bulk and young modulus for α-Al2O3 are determined to be 251 GPa and 423 GPa which is very close to the known experimental values of 280 GPa and 451 GPa.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187494","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-22
M. Isaev, Tokhirjon U. Atamirzaev, Mukhammadsodik N. Mamatkulov, Uralboy T. Asatov, Makhmudjon A. Tulametov
The temperature dependence of the mobility in chromium silicides in the temperature range of 80 ÷ 780 K was studied. The mobility gradually increases to a temperature of 350 K, then it saturates in the temperature range of 350 ÷ 450K, then gradually decreases. It is shown that the mobility depends on the scatter of charge of carriers on a crystal lattice, impurity ions, dislocations, and silicide inclusions. The frequency of collisions is proportional to T3/2, and the mobility varies with temperature as T-3/2. At high temperatures, phonons may be considered as “frozen” defects and collision frequency with its will proportional to T. The temperature dependences of the electrical conductivity in this temperature range were also studied. Areas with negative and positive temperature coefficients are revealed.
研究了硅化铬在 80 ÷ 780 K 温度范围内迁移率的温度依赖性。迁移率在温度为 350 K 时逐渐增大，然后在 350 ÷ 450 K 的温度范围内达到饱和，接着逐渐减小。研究表明，迁移率取决于载流子在晶格、杂质离子、位错和硅化物夹杂物上的电荷散射。碰撞频率与 T3/2 成正比，迁移率随温度的变化为 T-3/2。在高温下，声子可被视为 "冻结 "缺陷，其碰撞频率与 T 成正比。结果显示了具有负温度系数和正温度系数的区域。
{"title":"Study of the Mobility and Electrical Conductivity of Chromium Silicide","authors":"M. Isaev, Tokhirjon U. Atamirzaev, Mukhammadsodik N. Mamatkulov, Uralboy T. Asatov, Makhmudjon A. Tulametov","doi":"10.26565/2312-4334-2023-4-22","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-22","url":null,"abstract":"The temperature dependence of the mobility in chromium silicides in the temperature range of 80 ÷ 780 K was studied. The mobility gradually increases to a temperature of 350 K, then it saturates in the temperature range of 350 ÷ 450K, then gradually decreases. It is shown that the mobility depends on the scatter of charge of carriers on a crystal lattice, impurity ions, dislocations, and silicide inclusions. The frequency of collisions is proportional to T3/2, and the mobility varies with temperature as T-3/2. At high temperatures, phonons may be considered as “frozen” defects and collision frequency with its will proportional to T. The temperature dependences of the electrical conductivity in this temperature range were also studied. Areas with negative and positive temperature coefficients are revealed.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187539","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-10
Keshab Borah, Jadav Konch, Shyamanta Chakraborty
A numerical study of the heat and mass transfer of a micropolar nanofluid flow over a stretching sheet embedded in a porous medium is carried out in this investigation. The main objective of this work is to investigate the influence of Arrhenius activation energy, heat source and viscous dissipation on the fluid velocity, microrotation, temperature, and concentration distribution. The equations governing the flow are transformed into ordinary differential equations using appropriate similarity transformations and solved numerically using bvp4c solver in MATLAB. Graphs are plotted to study the influences of important parameters such as magnetic parameter, porosity parameter, thermophoresis parameter, Brownian motion parameter, activation energy parameter and Lewis number on velocity, microrotation, temperature and concentration distribution. The graphical representation explores that the velocity of the liquid diminishes for increasing values of magnetic parameter, whereas the angular velocity increases with it. This study also reports that an enhancement of temperature and concentration distribution is observed for the higher values of activation energy parameter, whereas the Lewis number shows the opposite behavior. The effects of various pertinent parameters are exposed realistically on skin friction coefficient, Nusselt and Sherwood numbers via tables. A comparison with previous work is conducted, and the results show good agreement.
{"title":"Effect of Arrhenius Activation Energy in MHD Micropolar Nanofluid Flow Along a Porous Stretching Sheet with Viscous Dissipation and Heat Source","authors":"Keshab Borah, Jadav Konch, Shyamanta Chakraborty","doi":"10.26565/2312-4334-2023-4-10","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-10","url":null,"abstract":"A numerical study of the heat and mass transfer of a micropolar nanofluid flow over a stretching sheet embedded in a porous medium is carried out in this investigation. The main objective of this work is to investigate the influence of Arrhenius activation energy, heat source and viscous dissipation on the fluid velocity, microrotation, temperature, and concentration distribution. The equations governing the flow are transformed into ordinary differential equations using appropriate similarity transformations and solved numerically using bvp4c solver in MATLAB. Graphs are plotted to study the influences of important parameters such as magnetic parameter, porosity parameter, thermophoresis parameter, Brownian motion parameter, activation energy parameter and Lewis number on velocity, microrotation, temperature and concentration distribution. The graphical representation explores that the velocity of the liquid diminishes for increasing values of magnetic parameter, whereas the angular velocity increases with it. This study also reports that an enhancement of temperature and concentration distribution is observed for the higher values of activation energy parameter, whereas the Lewis number shows the opposite behavior. The effects of various pertinent parameters are exposed realistically on skin friction coefficient, Nusselt and Sherwood numbers via tables. A comparison with previous work is conducted, and the results show good agreement.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187609","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-31
N. F. Zikrillaev, Kutub S. Ayupov, Manzura M. Shoabdirahimova, F. E. Urakova, Yoldoshali A. Abduganiev, Abdujalol A. Sattorov, Latofat S. Karieva
One of the crucial phenomena is auto-oscillations of current in elementary and binary (AIIIBV, AIIBVI) semiconductor materials, which allow the creation of solid-state oscillators with a wide frequency range from 10-3 to 10-6 Hz. In this paper, we show the results of a study on the effect of the degree of compensation (K) and the concentration of electroactive impurity selenium atoms on the excitation conditions and parameters (amplitude, frequency) of the auto-oscillation current associated with temperature and electrical instability in silicon. In the research, silicon doped with selenium atoms Si of identical geometrical dimensions has been used. The compensation degree of the initial boron atoms with impurity selenium atoms in the samples is in the range of K = 2NB/NSe = 0.94-1.1. It was found that excitation conditions, the amplitude and frequency of auto-oscillation current significantly vary depending on the degree of compensation of selenium atoms with boron atoms in the initial silicon. Obtained experimental results showed that the auto-oscillation current in silicon doped with impurity selenium atoms is characterized by ease of control with stable parameters (amplitude and frequency), which makes it possible based on this unique physical phenomenon to develop and create oscillatory circuits in information technology.
其中一个关键现象是基本半导体材料和二元半导体材料（AIIIBV、AIIBVI）中的电流自动振荡，它可以产生频率范围从 10-3 到 10-6 Hz 的固态振荡器。本文展示了补偿度（K）和电活性杂质硒原子浓度对硅中与温度和电不稳定性相关的自振荡电流的激发条件和参数（振幅、频率）的影响的研究结果。研究中使用了掺有硒原子 Si 的硅，其几何尺寸完全相同。样品中初始硼原子与杂质硒原子的补偿度范围为 K = 2NB/NSe = 0.94-1.1。实验发现，自振电流的激励条件、振幅和频率会因初始硅中硒原子与硼原子的补偿程度不同而发生显著变化。实验结果表明，掺杂杂质硒原子的硅中的自振电流具有易于控制、参数（振幅和频率）稳定的特点，这使得基于这种独特的物理现象开发和创建信息技术中的振荡电路成为可能。
{"title":"Effect of Compensation Degree and Concentration of Impurity Electroactive Selenium Atoms on Current Auto-Oscillation Parameters in Silicon","authors":"N. F. Zikrillaev, Kutub S. Ayupov, Manzura M. Shoabdirahimova, F. E. Urakova, Yoldoshali A. Abduganiev, Abdujalol A. Sattorov, Latofat S. Karieva","doi":"10.26565/2312-4334-2023-4-31","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-31","url":null,"abstract":"One of the crucial phenomena is auto-oscillations of current in elementary and binary (AIIIBV, AIIBVI) semiconductor materials, which allow the creation of solid-state oscillators with a wide frequency range from 10-3 to 10-6 Hz. In this paper, we show the results of a study on the effect of the degree of compensation (K) and the concentration of electroactive impurity selenium atoms on the excitation conditions and parameters (amplitude, frequency) of the auto-oscillation current associated with temperature and electrical instability in silicon. In the research, silicon doped with selenium atoms Si of identical geometrical dimensions has been used. The compensation degree of the initial boron atoms with impurity selenium atoms in the samples is in the range of K = 2NB/NSe = 0.94-1.1. It was found that excitation conditions, the amplitude and frequency of auto-oscillation current significantly vary depending on the degree of compensation of selenium atoms with boron atoms in the initial silicon. Obtained experimental results showed that the auto-oscillation current in silicon doped with impurity selenium atoms is characterized by ease of control with stable parameters (amplitude and frequency), which makes it possible based on this unique physical phenomenon to develop and create oscillatory circuits in information technology.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187705","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-06
Raksha Mundhra, P. Deka
Instability of ion cyclotron waves(ICWs) is investigated in presence of lower hybrid drift waves(LHDWs) turbulence. Plasma inhomogeneity in the Earth’s magnetopause region supports a range of low frequency drift wave turbulent fields due to gradients in density in different regions of the media. One of these drift phenomena is identified as lower hybrid drift waves (LHDWs) which satisfies resonant conditions ω − k · v = 0. We have considered a nonlinear wave-particle interaction model where the resonant wave that accelerates the particle in magnetopause may transfer its energy to ion cyclotron waves through a modulated field. In spite of the frequency gaps between the two waves, energy can be transferred nonlinearly to generate unstable ion cyclotron waves which always do not satisfy the resonant condition Ω−K · v ≠ 0 and the nonlinear scattering condition Ω − ω − (K − k) · v ̸= 0. Here, ω and Ω are frequencies of the resonant and the nonresonant waves respectively and k and K are the corresponding wave numbers. We have obtained a nonlinear dispersion relation for ion cyclotron waves(ICWs) in presence of lower hybrid drift waves(LHDWs)turbulence. The growth rate of the ion cyclotron waves using space observational data in the magnetopause region has been estimated.
研究了存在低混合漂移波（LHDWs）湍流时离子回旋波（ICWs）的不稳定性。由于介质不同区域的密度梯度，地球磁极区的等离子体不均匀性支持一系列低频漂移波湍流场。我们考虑了一个非线性波粒相互作用模型，在该模型中，加速磁层顶粒子的共振波可通过调制场将其能量传递给离子回旋波。尽管两种波之间存在频率差距，但能量可以非线性地传递，从而产生不稳定的离子回旋波，这些波总是不满足共振条件 Ω-K - v ≠ 0 和非线性散射条件 Ω - ω - (K - k) - v ̸=0。这里，ω 和 Ω 分别是共振波和非共振波的频率，k 和 K 是相应的波数。我们得到了离子回旋波（ICWs）在下混合漂移波（LHDWs）湍流中的非线性频散关系。利用磁极区的空间观测数据估算了离子回旋波的增长率。
{"title":"Instability of Ion Cyclotron Waves (ICWS) at the Expense of Lower Hybrid Drift Waves (LHDWS) Turbulence Energy","authors":"Raksha Mundhra, P. Deka","doi":"10.26565/2312-4334-2023-4-06","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-06","url":null,"abstract":"Instability of ion cyclotron waves(ICWs) is investigated in presence of lower hybrid drift waves(LHDWs) turbulence. Plasma inhomogeneity in the Earth’s magnetopause region supports a range of low frequency drift wave turbulent fields due to gradients in density in different regions of the media. One of these drift phenomena is identified as lower hybrid drift waves (LHDWs) which satisfies resonant conditions ω − k · v = 0. We have considered a nonlinear wave-particle interaction model where the resonant wave that accelerates the particle in magnetopause may transfer its energy to ion cyclotron waves through a modulated field. In spite of the frequency gaps between the two waves, energy can be transferred nonlinearly to generate unstable ion cyclotron waves which always do not satisfy the resonant condition Ω−K · v ≠ 0 and the nonlinear scattering condition Ω − ω − (K − k) · v ̸= 0. Here, ω and Ω are frequencies of the resonant and the nonresonant waves respectively and k and K are the corresponding wave numbers. We have obtained a nonlinear dispersion relation for ion cyclotron waves(ICWs) in presence of lower hybrid drift waves(LHDWs)turbulence. The growth rate of the ion cyclotron waves using space observational data in the magnetopause region has been estimated.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187454","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-30
Rustamjon G. Ikramov, K. Muminov, M. Nuritdinova, Bobur Q. Sutonov, Oybek T. Kholmirzayev, A’zamxo’ja A. Mamakhanov
In this work, defect absorption spectra for defects characteristic of hydrogenated amorphous silicon are theoretically studied. It is shown that in order to determine defect absorption spectra using the Kubo-Greenwood formula, the indefinite integral in this formula must be written in a certain form. It was discovered that electronic transitions involving defect states are divided into two parts depending on the energy of absorbed photons. The values of the partial defect absorption spectrum at low energies of absorbed photons have almost no effect on the overall defect absorption spectrum. It has been established that the main role in determining the defect absorption spectrum is played by partial spectra determined by optical transitions of electrons between allowed bands and defects. It is shown that with a power-law distribution of the density of electronic states in allowed bands, the spectra of optical transitions between them and defects do not depend on the value of this power.
{"title":"Dangerous Bonds Individual of Hydrogenated Amorphous Silicon and Defect Absorption Spectra","authors":"Rustamjon G. Ikramov, K. Muminov, M. Nuritdinova, Bobur Q. Sutonov, Oybek T. Kholmirzayev, A’zamxo’ja A. Mamakhanov","doi":"10.26565/2312-4334-2023-4-30","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-30","url":null,"abstract":"In this work, defect absorption spectra for defects characteristic of hydrogenated amorphous silicon are theoretically studied. It is shown that in order to determine defect absorption spectra using the Kubo-Greenwood formula, the indefinite integral in this formula must be written in a certain form. It was discovered that electronic transitions involving defect states are divided into two parts depending on the energy of absorbed photons. The values of the partial defect absorption spectrum at low energies of absorbed photons have almost no effect on the overall defect absorption spectrum. It has been established that the main role in determining the defect absorption spectrum is played by partial spectra determined by optical transitions of electrons between allowed bands and defects. It is shown that with a power-law distribution of the density of electronic states in allowed bands, the spectra of optical transitions between them and defects do not depend on the value of this power.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187518","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-45
V. Beresnev, S. Lytovchenko, M. Azarenkov, O. Maksakova, D. V. Horokh, B. O. Mazilin, Diana Kaynts, I. Doshchechkina, Оleg V. Gluhov
Two series of multilayer coatings with different numbers of bilayers (268 and 536, respectively) were synthesised using the cathodic vacuum-arc deposition (CVAD) with the simultaneous sputtering of two different cathodes. The first cathode was made of the multicomponent TiZrSiY material, and the second one was made of technical niobium. The coatings were condensed in a nitrogen atmosphere at a constant negative bias potential applied to the substrate. The resulting coatings have a distinct periodic structure composed of individual layers of (TiZrSiY)N and NbN with the thicknesses determined by the deposition interval (10 or 20 s, respectively). The total thicknesses of the coatings determined by the number of bilayers were 11 and 9 microns, respectively. The formation of polycrystalline TiN and NbN phases with grain size comparable to the size of the layers has been identified for both series of coatings. The layers exhibit a columnar structure growth with a predominant orientation (111). The hardness of the experimental coatings depends on the thickness of the layers and reaches 39.7 GPa for the coating with the smallest layer thickness. The friction coefficient of the obtained coatings varies from 0.512 to 0.498 and also depends on the thickness of the layers. A relatively large value of the friction coefficient is due to high roughness and the presence of a droplet fraction on the surface as well as in the volume of the coatings.
{"title":"Cathodic Vacuum ARC Multilayer Coatings (TiZrSiY)N/NbN: Structure and Properties Depending on The Deposition Interval of Alternate Layers","authors":"V. Beresnev, S. Lytovchenko, M. Azarenkov, O. Maksakova, D. V. Horokh, B. O. Mazilin, Diana Kaynts, I. Doshchechkina, Оleg V. Gluhov","doi":"10.26565/2312-4334-2023-4-45","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-45","url":null,"abstract":"Two series of multilayer coatings with different numbers of bilayers (268 and 536, respectively) were synthesised using the cathodic vacuum-arc deposition (CVAD) with the simultaneous sputtering of two different cathodes. The first cathode was made of the multicomponent TiZrSiY material, and the second one was made of technical niobium. The coatings were condensed in a nitrogen atmosphere at a constant negative bias potential applied to the substrate. The resulting coatings have a distinct periodic structure composed of individual layers of (TiZrSiY)N and NbN with the thicknesses determined by the deposition interval (10 or 20 s, respectively). The total thicknesses of the coatings determined by the number of bilayers were 11 and 9 microns, respectively. The formation of polycrystalline TiN and NbN phases with grain size comparable to the size of the layers has been identified for both series of coatings. The layers exhibit a columnar structure growth with a predominant orientation (111). The hardness of the experimental coatings depends on the thickness of the layers and reaches 39.7 GPa for the coating with the smallest layer thickness. The friction coefficient of the obtained coatings varies from 0.512 to 0.498 and also depends on the thickness of the layers. A relatively large value of the friction coefficient is due to high roughness and the presence of a droplet fraction on the surface as well as in the volume of the coatings.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187682","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 : 2023-12-02DOI: 10.26565/2312-4334-2023-4-34
S. Pogarsky, D. Mayboroda, Serhii M. Mykhaliuk
The paper presents the results of numerical modeling of the electrodynamic characteristics of a Vivaldi type patch antenna based on a circular disk resonator. The modeling was carried out using the semi-open resonator model by the finite element method (FEM) implemented in the HFFS package. The antenna was fed using a coplanar line segment. The antenna elements were placed over a grounded plane. The influence of design parameters and the function determining the curvature of the exponentially expanding slot discontinuity on the frequency, energy and polarization characteristics was investigated. It was established that with a certain selection of variable parameters, such an antenna can be matched with external circuits in the range from 7.03 GHz to 20 GHz with a level of VSWR values not exceeding 1.92. In the amplitude-frequency characteristic, fairly wide frequency bands with almost perfect matching are observed. The choice of the type of excitation element in the form of a section of the coplanar line made it possible to exclude additional elements inherent in Vivaldi antennas, namely, a section of the auxiliary strip line and a balancing resonator. This kind of antenna allows to form radiation patterns of various shapes from single-sided to cosecant quadrate. At the same time, in some intervals of observation angles, the formed fields turn out to be elliptically polarized with an ellipticity coefficient close to unity. The combination of the obtained results makes it possible to predict the use of this kind of antennas for operation with broadband signals.
{"title":"Influence of Aperture of Radiating Strip Structure on Electrodynamic Characteristics of Patch Antenna","authors":"S. Pogarsky, D. Mayboroda, Serhii M. Mykhaliuk","doi":"10.26565/2312-4334-2023-4-34","DOIUrl":"https://doi.org/10.26565/2312-4334-2023-4-34","url":null,"abstract":"The paper presents the results of numerical modeling of the electrodynamic characteristics of a Vivaldi type patch antenna based on a circular disk resonator. The modeling was carried out using the semi-open resonator model by the finite element method (FEM) implemented in the HFFS package. The antenna was fed using a coplanar line segment. The antenna elements were placed over a grounded plane. The influence of design parameters and the function determining the curvature of the exponentially expanding slot discontinuity on the frequency, energy and polarization characteristics was investigated. It was established that with a certain selection of variable parameters, such an antenna can be matched with external circuits in the range from 7.03 GHz to 20 GHz with a level of VSWR values not exceeding 1.92. In the amplitude-frequency characteristic, fairly wide frequency bands with almost perfect matching are observed. The choice of the type of excitation element in the form of a section of the coplanar line made it possible to exclude additional elements inherent in Vivaldi antennas, namely, a section of the auxiliary strip line and a balancing resonator. This kind of antenna allows to form radiation patterns of various shapes from single-sided to cosecant quadrate. At the same time, in some intervals of observation angles, the formed fields turn out to be elliptically polarized with an ellipticity coefficient close to unity. The combination of the obtained results makes it possible to predict the use of this kind of antennas for operation with broadband signals.","PeriodicalId":42569,"journal":{"name":"East European Journal of Physics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139187479","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：