V. S. Mukharovska, M. Derhachov, V.M. Moiseienko, B. Abu Sal
Single opal films and heterostructures based on them grown by the method of vertically moving meniscus are characterized by the reflection spectroscopy technique and then impregnated with the Eu(CH3COO)3 × H2O salt. The suppression of the Eu3+ ion emission in single opal films is clearly detected within the photonic stop-band range. The weaker manifestation of this effect in heterostructures is more likely due to interface defects causing both the appearance of permitted states in the photonic stop band and the scattering of radiation in the direction of observation. With the further impregnation of opal films with glycerol to reduce the dielectric contrast from 1.85 to 1.13, the emission spectrum is mainly determined by the Eu3+ coordination environment effects accompanied with the broadening of bands and the spectral intensity redistribution.
{"title":"Peculiarities of Eu3+ Photoluminescence in Opal Photonic Crystal Films and Heterostructures Based of Them","authors":"V. S. Mukharovska, M. Derhachov, V.M. Moiseienko, B. Abu Sal","doi":"10.15407/ujpe68.12.785","DOIUrl":"https://doi.org/10.15407/ujpe68.12.785","url":null,"abstract":"Single opal films and heterostructures based on them grown by the method of vertically moving meniscus are characterized by the reflection spectroscopy technique and then impregnated with the Eu(CH3COO)3 × H2O salt. The suppression of the Eu3+ ion emission in single opal films is clearly detected within the photonic stop-band range. The weaker manifestation of this effect in heterostructures is more likely due to interface defects causing both the appearance of permitted states in the photonic stop band and the scattering of radiation in the direction of observation. With the further impregnation of opal films with glycerol to reduce the dielectric contrast from 1.85 to 1.13, the emission spectrum is mainly determined by the Eu3+ coordination environment effects accompanied with the broadening of bands and the spectral intensity redistribution.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"11 47","pages":""},"PeriodicalIF":0.5,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139380162","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}
N. Balytska, P. P. Moskvin, G. Skyba, L.V. Rashkovetskyi, V. Kryzhanivskyy, L.G. Polonskyi
На прикладi мультифрактального аналiзу (МФА) зображень поверхонь наноплiвок, що синтезувалися золь-гель технологiєю в системi ZnО–SiO2, обговорюються особливостi застосування цього методу при отриманнi кiлькiсних характеристик поверхнi. Вхiдною iнформацiєю для реалiзацiї цього пiдходу до опису стану поверхонь були Second electron microscopy (SEM) зображення поверхнi зразкiв пiсля їх синтезу в заданих умовах. Чисельними розрахунками узагальнених статистичних сум для площi та об’ємiв просторових наноформ показано iснування їх лiнiйних залежностей вiд просторових розмiрiв, що є основним доказом наявностi самоподiбностi та фрактальної симетрiї серед зазначених геометричних параметрiв поверхнi. Наголошується на необхiдностi пiдвищення надiйностi визначення параметрiв МФ спектрiв та аналiзуються причини, що контролюють точнiсть абсолютних значень чисел Реньї. Вироблено рекомендацiї для мiнiмiзацiї похибок з метою отримання найбiльш вiрогiдних даних щодо МФ параметрiв поверхнi. Наведено залежностi чисел Реньї вiд температури синтезу шарiв ZnO–SiO2 золь-гель методом. Звертається увага на те, що для подальшого застосування результатiв МФА у фiзичних розрахунках необхiдно коректно вибирати тi числа Реньї, якi несуть у собi необхiдну iнформацiйну компоненту за модельованим фрактальним параметром. Обговорюються фiзичнi причини появи взаємозв’язку мiж параметрами МФ спектрiв для площi поверхнi та об’ємiв наноформ, що формуються на поверхнi плiвок, та умовами їх синтезу.
{"title":"Особливості досліджень поверхні плівок ZnO–SiO2 методом мультифрактального аналізу","authors":"N. Balytska, P. P. Moskvin, G. Skyba, L.V. Rashkovetskyi, V. Kryzhanivskyy, L.G. Polonskyi","doi":"10.15407/ujpe68.12.822","DOIUrl":"https://doi.org/10.15407/ujpe68.12.822","url":null,"abstract":"На прикладi мультифрактального аналiзу (МФА) зображень поверхонь наноплiвок, що синтезувалися золь-гель технологiєю в системi ZnО–SiO2, обговорюються особливостi застосування цього методу при отриманнi кiлькiсних характеристик поверхнi. Вхiдною iнформацiєю для реалiзацiї цього пiдходу до опису стану поверхонь були Second electron microscopy (SEM) зображення поверхнi зразкiв пiсля їх синтезу в заданих умовах. Чисельними розрахунками узагальнених статистичних сум для площi та об’ємiв просторових наноформ показано iснування їх лiнiйних залежностей вiд просторових розмiрiв, що є основним доказом наявностi самоподiбностi та фрактальної симетрiї серед зазначених геометричних параметрiв поверхнi. Наголошується на необхiдностi пiдвищення надiйностi визначення параметрiв МФ спектрiв та аналiзуються причини, що контролюють точнiсть абсолютних значень чисел Реньї. Вироблено рекомендацiї для мiнiмiзацiї похибок з метою отримання найбiльш вiрогiдних даних щодо МФ параметрiв поверхнi. Наведено залежностi чисел Реньї вiд температури синтезу шарiв ZnO–SiO2 золь-гель методом. Звертається увага на те, що для подальшого застосування результатiв МФА у фiзичних розрахунках необхiдно коректно вибирати тi числа Реньї, якi несуть у собi необхiдну iнформацiйну компоненту за модельованим фрактальним параметром. Обговорюються фiзичнi причини появи взаємозв’язку мiж параметрами МФ спектрiв для площi поверхнi та об’ємiв наноформ, що формуються на поверхнi плiвок, та умовами їх синтезу.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"7 10","pages":""},"PeriodicalIF":0.5,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139380806","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}
Y. Azhniuk, A. Gomonnai, V. Lopushansky, O. Gomonnai, T. Babuka, V. Loya, I. Voynarovych
TlInSe2 films with thickness from 10 to 200 nm were thermally evaporated on silicon and silicate glass substrates. Micro-Raman spectra measured at a moderate excitation (532 nm, 4 kW/cm2) confirm the amorphous character of the films. Narrow features revealed in the spectra at an excitation power density of 40 kW/cm2 show the evidence for the formation of TlInSe2 , TlSe, and In2Se3 crystallites in the laser spot. For thin (10–30 nm) films, the rod-shaped TlInSe2 crystallites are shown to be oriented within the film plane. The crystallite formation is governed by the thermal effect of the tightly focused laser beam.
{"title":"Laser-Induced Transformations in Thermally Evaporated Thin TlInSe2 Films Studied by Raman Spectroscopy","authors":"Y. Azhniuk, A. Gomonnai, V. Lopushansky, O. Gomonnai, T. Babuka, V. Loya, I. Voynarovych","doi":"10.15407/ujpe68.12.816","DOIUrl":"https://doi.org/10.15407/ujpe68.12.816","url":null,"abstract":"TlInSe2 films with thickness from 10 to 200 nm were thermally evaporated on silicon and silicate glass substrates. Micro-Raman spectra measured at a moderate excitation (532 nm, 4 kW/cm2) confirm the amorphous character of the films. Narrow features revealed in the spectra at an excitation power density of 40 kW/cm2 show the evidence for the formation of TlInSe2 , TlSe, and In2Se3 crystallites in the laser spot. For thin (10–30 nm) films, the rod-shaped TlInSe2 crystallites are shown to be oriented within the film plane. The crystallite formation is governed by the thermal effect of the tightly focused laser beam.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"13 2","pages":""},"PeriodicalIF":0.5,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139380578","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}
V. Trusova, P.E. Kuznietsov, O. Zhytniakivska, U. Tarabara, K.A. Vus, G.P. Gorbenko
The molecular interactions between the amyloid fibrils from Aβ-peptide, insulin and α-synuclein and fullerenes of different sizes, including C20, C36, C60, C70, and C84, have been studied using the molecular docking approach. The fullerenes are found to bind to the loop or turn region of Aβ- and α-synuclein fibrillar assemblies, but reside at the end of insulin amyloid fibers, reflecting the lower affinity of carbon nanostructures to the latter aggregated protein. For all systems studied here, the fullerene binding to amyloid fibrils is size-dependent, with larger fullerenes exhibiting a higher binding affinity and a lower total energy of complexation. The analysis of side chain contacts highlights the pivotal role of van der Waals forces, specifically, alkyl and π-alkyl interactions, in the stabilization of the fullerene-amyloid complexes. The results obtained are discussed in terms of novel nanocomposite materials based on carbon nanoparticles and fibrillar proteins, as well as of the fullerene role in anti-amyloid therapy.
{"title":"Fullerene-Amyloid Complexes as Perspective Nanocomposites: Molecular Docking Studies","authors":"V. Trusova, P.E. Kuznietsov, O. Zhytniakivska, U. Tarabara, K.A. Vus, G.P. Gorbenko","doi":"10.15407/ujpe68.12.807","DOIUrl":"https://doi.org/10.15407/ujpe68.12.807","url":null,"abstract":"The molecular interactions between the amyloid fibrils from Aβ-peptide, insulin and α-synuclein and fullerenes of different sizes, including C20, C36, C60, C70, and C84, have been studied using the molecular docking approach. The fullerenes are found to bind to the loop or turn region of Aβ- and α-synuclein fibrillar assemblies, but reside at the end of insulin amyloid fibers, reflecting the lower affinity of carbon nanostructures to the latter aggregated protein. For all systems studied here, the fullerene binding to amyloid fibrils is size-dependent, with larger fullerenes exhibiting a higher binding affinity and a lower total energy of complexation. The analysis of side chain contacts highlights the pivotal role of van der Waals forces, specifically, alkyl and π-alkyl interactions, in the stabilization of the fullerene-amyloid complexes. The results obtained are discussed in terms of novel nanocomposite materials based on carbon nanoparticles and fibrillar proteins, as well as of the fullerene role in anti-amyloid therapy.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"13 2","pages":""},"PeriodicalIF":0.5,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139380775","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}
In the presence of warm negative ions, ion-acoustic small-amplitude monotonic double layers are theoretically investigated in a plasma consisting of warm positive ions, warm positrons, and two-temperature non-isothermal electrons under the variation of the trapping parameters of electrons, concentration of positrons, and mass ratios of heavier negative ions to lighter positive ions by the Sagdeev pseudopotential method. The corresponding double layer solutions are also discussed for the same variation. Consequently, ion-acoustic solitary waves and double layers have been observed in auroral and magnetospheric plasmas with two-temperature electron distributions found in a laboratory, as well as in the space. This paper shows the effects of trapping parameters of electrons, positron concentration, and mass ratios of heavier negative ions to lighter positive ions on the Sagdeev potential function ψ(φ) and double layer solutions φDL for small-amplitude monotonic double layers. The results are presented graphically in Figs. 1 to 6.
{"title":"Existence of Small-Amplitude Double Layers in Two-Temperature Non-Isothermal Plasma","authors":"S. Chattopadhyay","doi":"10.15407/ujpe68.12.795","DOIUrl":"https://doi.org/10.15407/ujpe68.12.795","url":null,"abstract":"In the presence of warm negative ions, ion-acoustic small-amplitude monotonic double layers are theoretically investigated in a plasma consisting of warm positive ions, warm positrons, and two-temperature non-isothermal electrons under the variation of the trapping parameters of electrons, concentration of positrons, and mass ratios of heavier negative ions to lighter positive ions by the Sagdeev pseudopotential method. The corresponding double layer solutions are also discussed for the same variation. Consequently, ion-acoustic solitary waves and double layers have been observed in auroral and magnetospheric plasmas with two-temperature electron distributions found in a laboratory, as well as in the space. This paper shows the effects of trapping parameters of electrons, positron concentration, and mass ratios of heavier negative ions to lighter positive ions on the Sagdeev potential function ψ(φ) and double layer solutions φDL for small-amplitude monotonic double layers. The results are presented graphically in Figs. 1 to 6.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"8 2","pages":""},"PeriodicalIF":0.5,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139380631","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}
За допомогою комiркової моделi побудовано концентрацiйнi залежностi дзета-потенцiалу сироваткового альбумiну людини у водно-сольових розчинах; знайдено теоретичнi залежностi дзета-потенцiалу водно-сольових розчинiв сироваткового альбумiну людини вiд концентрацiї хлориду натрiю для рiзних концентрацiй альбумiну: а) за двох рiзних температур, 300 К та 318 К; б) за рiзних значень радiуса альбумiну, 40 Å та 45 Å. Виявлено, що змiна температури в розглянутих межах суттєво не впливає на дзета-потенцiал водно-сольових розчинiв альбумiну; збiльшення радiуса молекули на 5 Å приводить до помiтного зменшення дзета-потенцiалу вiд 3 до 10 одиниць в залежностi вiд концентрацiї солi. Отриманi данi є базисом для iнтерпретацiї значень дзета-потенцiалу альбумiну за наявностi рiзних патологiчних станiв.
利用细胞模型构建了盐水溶液中人血清白蛋白 zeta 电位的浓度相关性；发现了不同浓度白蛋白的盐水溶液的 zeta 电位与氯化钠浓度的理论相关性：a) 两种不同的温度（300 K 和 318 K）；b) 不同的白蛋白半径值（40 Å 和 45 Å）。研究发现，在所考虑的范围内，温度的变化不会对白蛋白水-盐溶液的 zeta 电位产生显著影响；分子半径增加 5 Å 会导致 zeta 电位明显下降 3 至 10 个单位，具体取决于盐浓度。所获得的数据是解释白蛋白在各种病理条件下的 zeta 电位值的基础。
{"title":"Температурна і концентраційна залежність дзета-потенціалу макромолекул альбуміну у водно-сольовому розчині згідно з комірковою моделлю","authors":"O.D. Stoliaryk, A. A. Guslisty, O. Khorolskyi","doi":"10.15407/ujpe68.11.742","DOIUrl":"https://doi.org/10.15407/ujpe68.11.742","url":null,"abstract":"За допомогою комiркової моделi побудовано концентрацiйнi залежностi дзета-потенцiалу сироваткового альбумiну людини у водно-сольових розчинах; знайдено теоретичнi залежностi дзета-потенцiалу водно-сольових розчинiв сироваткового альбумiну людини вiд концентрацiї хлориду натрiю для рiзних концентрацiй альбумiну: а) за двох рiзних температур, 300 К та 318 К; б) за рiзних значень радiуса альбумiну, 40 Å та 45 Å. Виявлено, що змiна температури в розглянутих межах суттєво не впливає на дзета-потенцiал водно-сольових розчинiв альбумiну; збiльшення радiуса молекули на 5 Å приводить до помiтного зменшення дзета-потенцiалу вiд 3 до 10 одиниць в залежностi вiд концентрацiї солi. Отриманi данi є базисом для iнтерпретацiї значень дзета-потенцiалу альбумiну за наявностi рiзних патологiчних станiв.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"37 9","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139176001","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 single composition of erbium-doped nickel zinc ferrite Ni0.5Zn0.5Fe1.95Er0.05O4 is synthesized by the sol-gel autocombustion process. The prepared composition was divided into five equal parts. One of the parts was an as-prepared sample, and remaining four other parts were calcinated at 600, 700, 800, and 900 ∘C to investigate the variation in structural and optical properties with the calcination temperature. The structural characterization was performed using XRD and SEM. Optical properties were analyzed using FTIR and UV-Visible spectral data. XRD patterns confirm the spinel cubic crystal structure and the Fd3m space group. The crystallite size was minimum for the as-prepared sample (17.9452 nm), and the crystallite size was maximum for the sample calcinated at 900 ∘C (29.8481 nm). SEM images revealed the grain size in the interval from 55.38 nm to 177.73 nm, and certain nanotubes were formed in the sample calcinated at 800 ∘C. Optical energy band gap was observed in the interval from 5.556 eV to 3.969 eV. All these testifies to the variations in structural and optical properties of Ni0.5Zn0.5Fe1.95Er0.05O4 with the calcination temperature.
{"title":"Effect of Calcination Temperature and Substitution of Erbium on Structural and Optical Properties of Nickel Zinc Ferrite Nanoparticles","authors":"K. Vijaya Kumar, S. D. Bhavani","doi":"10.15407/ujpe68.11.772","DOIUrl":"https://doi.org/10.15407/ujpe68.11.772","url":null,"abstract":"A single composition of erbium-doped nickel zinc ferrite Ni0.5Zn0.5Fe1.95Er0.05O4 is synthesized by the sol-gel autocombustion process. The prepared composition was divided into five equal parts. One of the parts was an as-prepared sample, and remaining four other parts were calcinated at 600, 700, 800, and 900 ∘C to investigate the variation in structural and optical properties with the calcination temperature. The structural characterization was performed using XRD and SEM. Optical properties were analyzed using FTIR and UV-Visible spectral data. XRD patterns confirm the spinel cubic crystal structure and the Fd3m space group. The crystallite size was minimum for the as-prepared sample (17.9452 nm), and the crystallite size was maximum for the sample calcinated at 900 ∘C (29.8481 nm). SEM images revealed the grain size in the interval from 55.38 nm to 177.73 nm, and certain nanotubes were formed in the sample calcinated at 800 ∘C. Optical energy band gap was observed in the interval from 5.556 eV to 3.969 eV. All these testifies to the variations in structural and optical properties of Ni0.5Zn0.5Fe1.95Er0.05O4 with the calcination temperature.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"48 5","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139174850","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. Jumabaev, A. Absanov, H. Hushvaktov, L.A. Bulavin
The mechanism of molecular complex formation in liquid propionic acid and its solutions is investigated. The anisotropic component of the Raman band of the C=O stretching vibration of pure propionic acid consists of three bands with maxima at 1661, 1700, and 1753 cm−1. The effect of varying the concentrations of solvents such as CCl4, acetonitrile, and water on this vibration mode is studied. The mechanism of formation of molecular complexes in solutions is determined using DFT calculations at the B3LYP/6-311++G(d,p) level of theory. The AIM, RDG, and NCI topological analyses are also performed to investigate the intermolecular interactions in the complexes.
{"title":"Intermolecular Interactions in Liquid Propionic Acid and Its Solutions: Raman and DFT Study","authors":"A. Jumabaev, A. Absanov, H. Hushvaktov, L.A. Bulavin","doi":"10.15407/ujpe68.11.750","DOIUrl":"https://doi.org/10.15407/ujpe68.11.750","url":null,"abstract":"The mechanism of molecular complex formation in liquid propionic acid and its solutions is investigated. The anisotropic component of the Raman band of the C=O stretching vibration of pure propionic acid consists of three bands with maxima at 1661, 1700, and 1753 cm−1. The effect of varying the concentrations of solvents such as CCl4, acetonitrile, and water on this vibration mode is studied. The mechanism of formation of molecular complexes in solutions is determined using DFT calculations at the B3LYP/6-311++G(d,p) level of theory. The AIM, RDG, and NCI topological analyses are also performed to investigate the intermolecular interactions in the complexes.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"50 ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139174135","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}
V. Yukhymchuk, V. Dzhagan, O.F. Isaieva, P. Lytvyn, A.A. Korchovyi, T.M. Sabov, V.B. Lozinskii, V.S. Yefanov, V.O. Osokin, Yu.A. Kurapov
Методом електронного розпилення графiту отримано нанометровi вуглецевi плiвки на металевих (мiдних, сталевих) та кремнiєвих пiдкладинках. Температура пiдкладок варiювалася вiд 350 до 600 оС з кроком 50 оС, а час напилення – вiд 1 до 10 с. Отриманi вуглецевi плiвки характеризувалися методами раманiвської спектроскопiї, X-променевої фотоелектронної спектроскопiї (XPS), атомно-силової мiкроскопiї та електронного парамагнiтного резонансу (EPR). З аналiзу раманiвських спектрiв встановлено, що при температурах металевих пiдкладок до 400 оС, сформованi на них вуглецевi плiвки є аморфними, при вищих температурах мають графiтоподiбну структуру. На кремнiєвих пiдкладинках при всiх температурах до 600 оС формуються аморфнi вуглецевi плiвки. Отриманi результати з раманiвських спектрiв корелюють з даними XPS. Показано, що на морфологiю плiвок впливає як температура пiдкладок, так i їхнiй тип (металева чи кремнiєва). Зi збiльшенням температури пiдкладок вiд 350 до 600 оС середнi розмiри нерiвностей на поверхнi вуглецевих плiвок зростають як на металевих, так i на кремнiєвiй пiдкладинках. EPR дослiдження показали, що наявнi в плiвках структурнi дефекти, якi зумовлюють прояв у раманiвських спектрах так званих дефектних смуг (D та D′), є не парамагнiтними.
{"title":"Структурні та морфологічні властивості нанометрових вуглецевих плівок, отриманих розпиленням графіту електронним променем","authors":"V. Yukhymchuk, V. Dzhagan, O.F. Isaieva, P. Lytvyn, A.A. Korchovyi, T.M. Sabov, V.B. Lozinskii, V.S. Yefanov, V.O. Osokin, Yu.A. Kurapov","doi":"10.15407/ujpe68.11.764","DOIUrl":"https://doi.org/10.15407/ujpe68.11.764","url":null,"abstract":"Методом електронного розпилення графiту отримано нанометровi вуглецевi плiвки на металевих (мiдних, сталевих) та кремнiєвих пiдкладинках. Температура пiдкладок варiювалася вiд 350 до 600 оС з кроком 50 оС, а час напилення – вiд 1 до 10 с. Отриманi вуглецевi плiвки характеризувалися методами раманiвської спектроскопiї, X-променевої фотоелектронної спектроскопiї (XPS), атомно-силової мiкроскопiї та електронного парамагнiтного резонансу (EPR). З аналiзу раманiвських спектрiв встановлено, що при температурах металевих пiдкладок до 400 оС, сформованi на них вуглецевi плiвки є аморфними, при вищих температурах мають графiтоподiбну структуру. На кремнiєвих пiдкладинках при всiх температурах до 600 оС формуються аморфнi вуглецевi плiвки. Отриманi результати з раманiвських спектрiв корелюють з даними XPS. Показано, що на морфологiю плiвок впливає як температура пiдкладок, так i їхнiй тип (металева чи кремнiєва). Зi збiльшенням температури пiдкладок вiд 350 до 600 оС середнi розмiри нерiвностей на поверхнi вуглецевих плiвок зростають як на металевих, так i на кремнiєвiй пiдкладинках. EPR дослiдження показали, що наявнi в плiвках структурнi дефекти, якi зумовлюють прояв у раманiвських спектрах так званих дефектних смуг (D та D′), є не парамагнiтними.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"202 ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139175198","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}
C. Balaji, S. Maruthamanikandan, C. Rudresha, V. Vidya Shree
The impact of the sinusoidal mode of a magnetic field involving time fluctuations on the threshold of the ferromagnetic smart liquid convection in a saturated permeable medium is investigated using the regular perturbation technique. The Darcy–Brinkman model with anisotropic permeability is used to describe the flow through porous media. The thermal anisotropy is implemented in the energy equation. The problem might be useful in thermal engineering applications such as dynamic loudspeakers and computer hard discs and in medical applications like the treatment of tumor cells and the cell separation, to name a few. The regular perturbation technique is based on the minimum amplitude of a magnetic field modulation, and the onset criterion is dealt with in terms of a correction in the critical Rayleigh number and wavenumber. The thermal Rayleigh number correction depends on the magnetic field modulation frequency, magnetic force, anisotropies, porosity, and Prandtl number. At moderate values of the magnetic field modulation frequency, the impact of various physical factors is perceived to be noteworthy. The influences of the magnetic mechanism, Prandtl number, porosity parameter, and Brinkman number are shown to augment the destabilizing effect of the magnetic field modulation for moderate values of the frequency of a modulation. However, the destabilizing effect of the magnetic field modulation is diminished due to an increase in the values of the mechanical anisotropy parameter and thermal anisotropy parameter. The study reveals that the effect of the magnetic field modulation could be exploited to control the convective instability in an anisotropic porous medium saturated by a ferromagnetic fluid.
{"title":"Anisotropic Darcy–Brinkman Magnetic Fluid Convection under the Influence of a Time-Dependent Sinusoidal Magnetic Field","authors":"C. Balaji, S. Maruthamanikandan, C. Rudresha, V. Vidya Shree","doi":"10.15407/ujpe68.11.730","DOIUrl":"https://doi.org/10.15407/ujpe68.11.730","url":null,"abstract":"The impact of the sinusoidal mode of a magnetic field involving time fluctuations on the threshold of the ferromagnetic smart liquid convection in a saturated permeable medium is investigated using the regular perturbation technique. The Darcy–Brinkman model with anisotropic permeability is used to describe the flow through porous media. The thermal anisotropy is implemented in the energy equation. The problem might be useful in thermal engineering applications such as dynamic loudspeakers and computer hard discs and in medical applications like the treatment of tumor cells and the cell separation, to name a few. The regular perturbation technique is based on the minimum amplitude of a magnetic field modulation, and the onset criterion is dealt with in terms of a correction in the critical Rayleigh number and wavenumber. The thermal Rayleigh number correction depends on the magnetic field modulation frequency, magnetic force, anisotropies, porosity, and Prandtl number. At moderate values of the magnetic field modulation frequency, the impact of various physical factors is perceived to be noteworthy. The influences of the magnetic mechanism, Prandtl number, porosity parameter, and Brinkman number are shown to augment the destabilizing effect of the magnetic field modulation for moderate values of the frequency of a modulation. However, the destabilizing effect of the magnetic field modulation is diminished due to an increase in the values of the mechanical anisotropy parameter and thermal anisotropy parameter. The study reveals that the effect of the magnetic field modulation could be exploited to control the convective instability in an anisotropic porous medium saturated by a ferromagnetic fluid.","PeriodicalId":23400,"journal":{"name":"Ukrainian Journal of Physics","volume":"9 8","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173556","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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