Методом електронного парамагнiтного резонансу дослiджено властивостi спiвполiмеру БСП-7, високомiцних i високомодульних кевлароподiбних органiчних волокон (ОВ) терлону та внiївлону в ролi наповнювачiв, а також компози-тiв БСП-7/ОВ. Встановлено наявнiсть та визначено властивостi дефектiв рiзного типу i магнiтних домiшок у вихiдних матерiалах та виготовлених композитах. Виявлено вплив взаємодiї матрицi з наповнювачами та оточуючим середовищем. У терлонi зареєстровано значну концентрацiю азотовмiсних радикалiв, пов’язаних iз наявнiстю мономерiв дiамiнiв у його структурi, що може негативно впливати на фiзико-механiчнi характеристики композитiв. З урахуванням отриманих даних розроблено ефективнi органопластики БСП-7/ОВ. Вимiрювання їх трибологiчних властивостей показали, що додавання оптимальної концентрацiї ОВ до полiмерної матрицi БСП-7 сприяє значному змен-шенню коефiцiєнта тертя, iнтенсивностi лiнiйного зношування та тепловидiлення. Кращi результати показали композити з терлоном, що пояснюється не тiльки його бiльш високим модулем пружностi, а i високим ступенем кристалiчностi структури, на вiдмiну вiд внiївлону з його майже аморфною гетероциклiчною структурою. Крiм того, процес синтезу композитiв передбачає застосування достатньо високих температур i тиску, в результатi чого азотнi радикали терлону руйнуються, i їхнiй негативний вплив на довготермiнову стабiльнiсть характеристик композита нiвелюється.
{"title":"Магніторезонансні та трибологічні властивості органопластів на основі співполімеру БСП-7","authors":"M.O. Graschenkova, A.-M.V. Tomina, O.I. Burya, S.V. Krasnovyd, A.A. Konchyts’, B.D. Shanina","doi":"10.15407/ujpe68.9.619","DOIUrl":"https://doi.org/10.15407/ujpe68.9.619","url":null,"abstract":"Методом електронного парамагнiтного резонансу дослiджено властивостi спiвполiмеру БСП-7, високомiцних i високомодульних кевлароподiбних органiчних волокон (ОВ) терлону та внiївлону в ролi наповнювачiв, а також компози-тiв БСП-7/ОВ. Встановлено наявнiсть та визначено властивостi дефектiв рiзного типу i магнiтних домiшок у вихiдних матерiалах та виготовлених композитах. Виявлено вплив взаємодiї матрицi з наповнювачами та оточуючим середовищем. У терлонi зареєстровано значну концентрацiю азотовмiсних радикалiв, пов’язаних iз наявнiстю мономерiв дiамiнiв у його структурi, що може негативно впливати на фiзико-механiчнi характеристики композитiв. З урахуванням отриманих даних розроблено ефективнi органопластики БСП-7/ОВ. Вимiрювання їх трибологiчних властивостей показали, що додавання оптимальної концентрацiї ОВ до полiмерної матрицi БСП-7 сприяє значному змен-шенню коефiцiєнта тертя, iнтенсивностi лiнiйного зношування та тепловидiлення. Кращi результати показали композити з терлоном, що пояснюється не тiльки його бiльш високим модулем пружностi, а i високим ступенем кристалiчностi структури, на вiдмiну вiд внiївлону з його майже аморфною гетероциклiчною структурою. Крiм того, процес синтезу композитiв передбачає застосування достатньо високих температур i тиску, в результатi чого азотнi радикали терлону руйнуються, i їхнiй негативний вплив на довготермiнову стабiльнiсть характеристик композита нiвелюється.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"83 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135617960","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}
Enzymatic reactions are the basis of many biotechnological manufacturing and biomedical diagnostic procedures that require effective methods of monitoring over the reaction course. In the current paper, we present the results of the development of a new approach within the differential microwave dielectrometry method for the non-invasive monitoring of the course of enzymatic reactions based on the complex permittivity changes of these reactive mixture solutions in real time at a fixed frequency of 31.82 GHz. The dynamic studies of the dielectric parameters of selected enzymatic systems containing a protein substrate (immunoglobulin G, human serum albumin) and enzyme trypsin. The developed differential microwave dielectrometry setup has been performed to verify the proposed approach effectiveness for the enzymatic reaction monitoring in biomedical practice and the food industry. Our microwave dielectrometry results have been validated by the results of the UV-Vis spectrophotometry method for selected enzymatic systems. We propose a new approach to use the differential microwave dielectrometry method with high sensitivity (in average 0.5% and 3÷5% for the real and imaginary parts of the complex permittivity, respectively) to estimate the course of enzymatic reactions in real time.
{"title":"Monitoring of the Enzymatic Reactions Course by Differential Microwave Dielectrometry Method in Real Time","authors":"K.S. Kuznetsova, V.A. Pashynska, Z.E. Eremenko, O.I. Shubnyi, A.V. Martynov, A.A. Prokopenko","doi":"10.15407/ujpe68.9.608","DOIUrl":"https://doi.org/10.15407/ujpe68.9.608","url":null,"abstract":"Enzymatic reactions are the basis of many biotechnological manufacturing and biomedical diagnostic procedures that require effective methods of monitoring over the reaction course. In the current paper, we present the results of the development of a new approach within the differential microwave dielectrometry method for the non-invasive monitoring of the course of enzymatic reactions based on the complex permittivity changes of these reactive mixture solutions in real time at a fixed frequency of 31.82 GHz. The dynamic studies of the dielectric parameters of selected enzymatic systems containing a protein substrate (immunoglobulin G, human serum albumin) and enzyme trypsin. The developed differential microwave dielectrometry setup has been performed to verify the proposed approach effectiveness for the enzymatic reaction monitoring in biomedical practice and the food industry. Our microwave dielectrometry results have been validated by the results of the UV-Vis spectrophotometry method for selected enzymatic systems. We propose a new approach to use the differential microwave dielectrometry method with high sensitivity (in average 0.5% and 3÷5% for the real and imaginary parts of the complex permittivity, respectively) to estimate the course of enzymatic reactions in real time.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135618504","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}
One-dimensional nanostructures of PANI: PVA-g-EI nanocomposite are prepared by the interfacial polymerization method. The properties of a resulting green powder are studied by the X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and infrared spectroscopy (FTIR). Prepared thin films were characterized by UV-Vis and photoluminescence (PL) spectroscopies. The XRD pattern of the nanocomposite shows that the higher volume fraction of crystalline phases corresponds to the PANI polymer with the accepted monoclinic unit cell of PVA. Nano-sized irregular particles arranged in clusters appear in the TEM measurements and SEM images, which testifies to the agglomeration without uniform packing. EDX confirms that the PVA-g-EI is incorporated in the structure of the polymer nanocomposite. A significant shift in the absorption edge with three PL independent emission peaks again confirms that PANI/PVA-g-EI form a nanocomposite.
{"title":"Synthesis and Characterization of a Novel Nanocomposite Polymer","authors":"A.S. Al-Kabbi, S.J. Abbas","doi":"10.15407/ujpe68.9.638","DOIUrl":"https://doi.org/10.15407/ujpe68.9.638","url":null,"abstract":"One-dimensional nanostructures of PANI: PVA-g-EI nanocomposite are prepared by the interfacial polymerization method. The properties of a resulting green powder are studied by the X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and infrared spectroscopy (FTIR). Prepared thin films were characterized by UV-Vis and photoluminescence (PL) spectroscopies. The XRD pattern of the nanocomposite shows that the higher volume fraction of crystalline phases corresponds to the PANI polymer with the accepted monoclinic unit cell of PVA. Nano-sized irregular particles arranged in clusters appear in the TEM measurements and SEM images, which testifies to the agglomeration without uniform packing. EDX confirms that the PVA-g-EI is incorporated in the structure of the polymer nanocomposite. A significant shift in the absorption edge with three PL independent emission peaks again confirms that PANI/PVA-g-EI form a nanocomposite.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135617958","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}
An analytic procedure for calculating the critical temperature and estimating the size of the critical region for a cell fluid model is developed. Our numerical calculations are illustrated by the case of the Morse potential parameters characterizing the alkali metals (sodium and potassium). The critical temperatures found for liquid sodium and potassium as solutions of the resulting quadratic equation agree with experimental data. The expression for the relative temperature determining the critical region size is obtained proceeding from the condition for the critical regime existence. In the cases of sodium and potassium, the value of this temperature is of the order of a few hundredths.
{"title":"Analytic Calculation of the Critical Temperature and Estimation of the Critical Region Size for a Fluid Model","authors":"I.V. Pylyuk, M.P. Kozlovskii, O.A. Dobush","doi":"10.15407/ujpe68.9.601","DOIUrl":"https://doi.org/10.15407/ujpe68.9.601","url":null,"abstract":"An analytic procedure for calculating the critical temperature and estimating the size of the critical region for a cell fluid model is developed. Our numerical calculations are illustrated by the case of the Morse potential parameters characterizing the alkali metals (sodium and potassium). The critical temperatures found for liquid sodium and potassium as solutions of the resulting quadratic equation agree with experimental data. The expression for the relative temperature determining the critical region size is obtained proceeding from the condition for the critical regime existence. In the cases of sodium and potassium, the value of this temperature is of the order of a few hundredths.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135618845","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}
Yu.F. Zabashta, V.I. Kovalchuk, P. Kopčanský, I. Safarik, M.M. Lazarenko, L.Yu. Vergun, L.A. Bulavin
Розглядається можливiсть створення на основi бiнарного водного розчину полiмерних та олiгомерних молекул гiдрогелiв нового типу – ламелярно-ланцюгових – iз каркасом пiдвищеної жорсткостi. Запропоновано гiпотетичну модель такого каркасу, структурними елементами якого є олiгомернi ламели та полiмернi ланцюги. Цi елементи з’єднуються завдяки тому, що кiнцi полiмерних ланцюгiв втягуються в пори ламел. Отримано формулу для вiльної енергiї такої системи. Показано, що збiльшення концентрацiї полiмера має привести до взаємного зближення ламел. Цей висновок узгоджується з результатами проведеного методом малокутового розсiяння рентгенiвських променiв експерименту, в якому дослiджувались бiнарнi воднi розчини полiмера (полiетиленглiколя) та олiгомера (додецилсульфата натрiю) з рiзними концентрацiями.
本研究考虑了在聚合物和低聚物分子的二元水溶液的基础上制造一种新型水凝胶（片状链水凝胶）的可能性，这种水凝胶的框架具有更高的刚性。提出了这种框架的假想模型，其结构元素是低聚物薄片和聚合物链。由于聚合物链的末端被卷入薄片的孔隙中，因此这些元素相互连接。我们得到了这种系统的自由能公式。结果表明，聚合物浓度的增加会导致薄片相互靠近。这一结论与用小角 X 射线散射法进行的实验结果一致，该实验研究了不同浓度的聚合物（聚乙二醇）和低聚物（十二烷基硫酸钠）的二元水溶液。
{"title":"Ламелярно-ланцюгові гідрогелі: особливості структури","authors":"Yu.F. Zabashta, V.I. Kovalchuk, P. Kopčanský, I. Safarik, M.M. Lazarenko, L.Yu. Vergun, L.A. Bulavin","doi":"10.15407/ujpe68.8.536","DOIUrl":"https://doi.org/10.15407/ujpe68.8.536","url":null,"abstract":"Розглядається можливiсть створення на основi бiнарного водного розчину полiмерних та олiгомерних молекул гiдрогелiв нового типу – ламелярно-ланцюгових – iз каркасом пiдвищеної жорсткостi. Запропоновано гiпотетичну модель такого каркасу, структурними елементами якого є олiгомернi ламели та полiмернi ланцюги. Цi елементи з’єднуються завдяки тому, що кiнцi полiмерних ланцюгiв втягуються в пори ламел. Отримано формулу для вiльної енергiї такої системи. Показано, що збiльшення концентрацiї полiмера має привести до взаємного зближення ламел. Цей висновок узгоджується з результатами проведеного методом малокутового розсiяння рентгенiвських променiв експерименту, в якому дослiджувались бiнарнi воднi розчини полiмера (полiетиленглiколя) та олiгомера (додецилсульфата натрiю) з рiзними концентрацiями.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135895128","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}
Experimental studies devoted to the creation of the modern photocathodes or efficient field emission cathodes with lowered work function or low/negative electron affinity are reviewed. We present theoretical models, where the electron affinity lowering is associated with the influence of electrically charged layers at the semiconductor/insulator interface. Modern experimental techniques of measuring the work function or the electron affinity and technologies aimed at fabricating the surfaces with low work function/electron affinity are described. In the framework of a simple theoretical model developed by the authors, it has been demonstrated that the presence of a dipole layer (e.g., composed of negatively charged oxygen ions and positively charged rare earth ions) at the semiconductor surface can lower the electron affinity by up to 3 eV provided equal concentrations of oppositely charged adsorbate ions. It is also shown that if the surface concentration of negatively charged oxygen ions is higher than the surface concentration of positively charged metal ions, the lowering of the electron affinity becomes smaller due to the upward band bending in the space charge region in the semiconductor; otherwise, the lowering of the electron affinity becomes larger due to the downward band bending. This effect allows technological proposals to be formulated for obtaining surfaces with minimum work function values in modern field-emission-based electronic devices. In the framework of the proposed model, the work function was evaluated for the OH-functionalized MXene. The corresponding value for the unfunctionalized MXene equals about 4.5 eV, being practically independent of the number of Ti and C layers (from 1 to 9 layers). The OH-functionalization lowers it down to about 1.6 eV, and this value is also practically independent of the number of atomic layers in MXene. Experimental approaches to obtain cathodes with low work function/low electron affinity are described. They are aimed at creating a spatial separation of electric charges in the near-surface cathode region perpendicularly to the surface plane. The corresponding spatial distributions of positive and negative charges are characterized by their localization either in two different atomic planes or in one plane and an extended space region (the latter variant is typical of semiconductor substrates). The technologies for producing such surfaces are based on various methods of adsorbate deposition onto the metal or semiconductor substrate: physical vapor deposition, chemical vapor deposition, liquid phase deposition, diffusion from the substrate bulk, and so forth. Particular attention is paid to the experimental works dealing with the adsorbtion of rare earth metals (Ce, Gd, Eu) and the coadsorbtion of oxygen onto the Si, Ge, and Mo surfaces (in a nano-structured state as well), which results in the dipole layer formation and the work function reduction.
{"title":"Surfaces with Lowered Electron Work Function: Problems of Their Creation and Theoretical Description. A Review","authors":"M.V. Strikha, A.M. Goriachko","doi":"10.15407/ujpe68.8.549","DOIUrl":"https://doi.org/10.15407/ujpe68.8.549","url":null,"abstract":"Experimental studies devoted to the creation of the modern photocathodes or efficient field emission cathodes with lowered work function or low/negative electron affinity are reviewed. We present theoretical models, where the electron affinity lowering is associated with the influence of electrically charged layers at the semiconductor/insulator interface. Modern experimental techniques of measuring the work function or the electron affinity and technologies aimed at fabricating the surfaces with low work function/electron affinity are described. In the framework of a simple theoretical model developed by the authors, it has been demonstrated that the presence of a dipole layer (e.g., composed of negatively charged oxygen ions and positively charged rare earth ions) at the semiconductor surface can lower the electron affinity by up to 3 eV provided equal concentrations of oppositely charged adsorbate ions. It is also shown that if the surface concentration of negatively charged oxygen ions is higher than the surface concentration of positively charged metal ions, the lowering of the electron affinity becomes smaller due to the upward band bending in the space charge region in the semiconductor; otherwise, the lowering of the electron affinity becomes larger due to the downward band bending. This effect allows technological proposals to be formulated for obtaining surfaces with minimum work function values in modern field-emission-based electronic devices. In the framework of the proposed model, the work function was evaluated for the OH-functionalized MXene. The corresponding value for the unfunctionalized MXene equals about 4.5 eV, being practically independent of the number of Ti and C layers (from 1 to 9 layers). The OH-functionalization lowers it down to about 1.6 eV, and this value is also practically independent of the number of atomic layers in MXene. Experimental approaches to obtain cathodes with low work function/low electron affinity are described. They are aimed at creating a spatial separation of electric charges in the near-surface cathode region perpendicularly to the surface plane. The corresponding spatial distributions of positive and negative charges are characterized by their localization either in two different atomic planes or in one plane and an extended space region (the latter variant is typical of semiconductor substrates). The technologies for producing such surfaces are based on various methods of adsorbate deposition onto the metal or semiconductor substrate: physical vapor deposition, chemical vapor deposition, liquid phase deposition, diffusion from the substrate bulk, and so forth. Particular attention is paid to the experimental works dealing with the adsorbtion of rare earth metals (Ce, Gd, Eu) and the coadsorbtion of oxygen onto the Si, Ge, and Mo surfaces (in a nano-structured state as well), which results in the dipole layer formation and the work function reduction.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135790329","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}
A new hybrid multiscaling model has been developed on the basis of the modified control volume function. Following the two-phase analogy of the same substance, the continuum and particle representations are coupled together in the framework of the mass and momentum conservation laws. The new functional form of the control volume function is elaborated by using the continuum discretization principle based on the Delaunay triangulation. The derived mass and momentum equations possess the invariant form for both micro-scale particle and large-scale continuum representations.
{"title":"The Multiscale Hybrid Method with a Localized Constraint. I. A Modified Control Volume Function for the Hybridized Mass and Momentum Equations","authors":"M. Bakumenko, V. Bardik, D. Nerukh","doi":"10.15407/ujpe68.8.517","DOIUrl":"https://doi.org/10.15407/ujpe68.8.517","url":null,"abstract":"A new hybrid multiscaling model has been developed on the basis of the modified control volume function. Following the two-phase analogy of the same substance, the continuum and particle representations are coupled together in the framework of the mass and momentum conservation laws. The new functional form of the control volume function is elaborated by using the continuum discretization principle based on the Delaunay triangulation. The derived mass and momentum equations possess the invariant form for both micro-scale particle and large-scale continuum representations.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135895127","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}
T.S. Vlasenko, D.A. Gavryushenko, K.V. Cherevko, L.A. Bulavin
В рамках нерiвноважної статистичної термодинамiки роз-винено теоретичну модель дифузiї в обмежених багато-компонентних рiдинних системах за наявностi радiацiйного опромiнення, що дозволяє визначати стацiонарнi дифузiйнi потоки з урахуванням спричинених опромiненням змiн у рiвноважнiй частинi коефiцiєнта дифузiї. Для низки модельних розчинiв проведено оцiнку ентропiйних внескiв у рiвноважну частину коефiцiєнта дифузiї, спричинених змiною термодинамiчних властивостей рiдинних систем пiд впливом радiацiйного опромiнення. Показано, що опромiнення медико-бiологiчних рiдинних систем в неперервному режимi може призводити до збiльшення насичення тканин киснем за рахунок зменшення стабiлiзацiйних ефектiв, що спостерiгаються при полегшенiй дифузiї за вiдсутностi опромiнення.
{"title":"Вплив радіаційного опромінення на параметри полегшеної дифузії модельної медико-біологічної системи","authors":"T.S. Vlasenko, D.A. Gavryushenko, K.V. Cherevko, L.A. Bulavin","doi":"10.15407/ujpe68.8.525","DOIUrl":"https://doi.org/10.15407/ujpe68.8.525","url":null,"abstract":"В рамках нерiвноважної статистичної термодинамiки роз-винено теоретичну модель дифузiї в обмежених багато-компонентних рiдинних системах за наявностi радiацiйного опромiнення, що дозволяє визначати стацiонарнi дифузiйнi потоки з урахуванням спричинених опромiненням змiн у рiвноважнiй частинi коефiцiєнта дифузiї. Для низки модельних розчинiв проведено оцiнку ентропiйних внескiв у рiвноважну частину коефiцiєнта дифузiї, спричинених змiною термодинамiчних властивостей рiдинних систем пiд впливом радiацiйного опромiнення. Показано, що опромiнення медико-бiологiчних рiдинних систем в неперервному режимi може призводити до збiльшення насичення тканин киснем за рахунок зменшення стабiлiзацiйних ефектiв, що спостерiгаються при полегшенiй дифузiї за вiдсутностi опромiнення.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135829678","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}
S. Staryi, I. Lysjuk, O. Golenkov, Z. Tsybrii, S. Danilov, J. Gumenjuk-Sichevska, K. Andrieieva, M. Smolii, F. Sizov
The lifetimes of photoconductive decay carriers under interband and intraband excitations are studied in epitaxial layers of narrow-gap Hg1−xCdxTe (x ∼0.2). Samples with large distances (>3 mm) between small-area electrical contacts and small distances (∼10 μm) with largearea contacts (THz antennas) are studied. The lifetimes of decay carriers for intraband and interband excitations are measured and compared. It has been established that, in samples with n-type conductivity, the lifetimes are comparable (in the interval of 40 ns) for both methods of excitation. At the same time, in samples with a small distance between contacts and a large area (bow-tie antennas), contacts make the main contribution to recombination. The elimination of recombination at the contacts leads to a lifetime of ∼10−6 s.
{"title":"Carrier Decay Lifetimes in the Narrow-gap Hg1–xCdxTe at the Interband and Intraband Excitations","authors":"S. Staryi, I. Lysjuk, O. Golenkov, Z. Tsybrii, S. Danilov, J. Gumenjuk-Sichevska, K. Andrieieva, M. Smolii, F. Sizov","doi":"10.15407/ujpe68.8.543","DOIUrl":"https://doi.org/10.15407/ujpe68.8.543","url":null,"abstract":"The lifetimes of photoconductive decay carriers under interband and intraband excitations are studied in epitaxial layers of narrow-gap Hg1−xCdxTe (x ∼0.2). Samples with large distances (>3 mm) between small-area electrical contacts and small distances (∼10 μm) with largearea contacts (THz antennas) are studied. The lifetimes of decay carriers for intraband and interband excitations are measured and compared. It has been established that, in samples with n-type conductivity, the lifetimes are comparable (in the interval of 40 ns) for both methods of excitation. At the same time, in samples with a small distance between contacts and a large area (bow-tie antennas), contacts make the main contribution to recombination. The elimination of recombination at the contacts leads to a lifetime of ∼10−6 s.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135829399","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}
E. V. Gorbar, T. Gorkavenko, V. Gorkavenko, O. M. Teslyk
The generation of magnetic fields during the inflation in an electromagnetic model with a non-local form factor in Maxwell’s action is studied. The equations of motion for the electromagnetic field are derived and solved. It is found that the conformal symmetry breaking due to the non-local form factor does not lead to the generation of magnetic fields during the inflation in the absence of an interaction with the inflaton field. If such a coupling takes place, then the presence of the form factor inhibits the generation of primordial magnetic fields compared to the case where the non-local form factor is absent.
{"title":"Magnetogenesis in Non-Local Models during Inflation","authors":"E. V. Gorbar, T. Gorkavenko, V. Gorkavenko, O. M. Teslyk","doi":"10.15407/ujpe68.10.647","DOIUrl":"https://doi.org/10.15407/ujpe68.10.647","url":null,"abstract":"The generation of magnetic fields during the inflation in an electromagnetic model with a non-local form factor in Maxwell’s action is studied. The equations of motion for the electromagnetic field are derived and solved. It is found that the conformal symmetry breaking due to the non-local form factor does not lead to the generation of magnetic fields during the inflation in the absence of an interaction with the inflaton field. If such a coupling takes place, then the presence of the form factor inhibits the generation of primordial magnetic fields compared to the case where the non-local form factor is absent.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"145 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139324210","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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