Кафедра фізико-математичних наук
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Item α + t and α + 3He Interactions and the Excited-State Spectrum of 6Li Nucleus(2025) Povoroznyk, Orest; Gorpinich, Olha; Roznyuk, Yu.; Jachmenjov, O.A kinematically complete analysis of the 3He(α, pα)d reaction on 3He nuclei of radiogenic origin accumulated in titanium-tritium targets, as well as the 3H(α, dα)n and 3H(α, τt)n reactions on tritium nuclei accumulated on the same targets, has been carried out to study the excitation spectrum of 6Li nucleus at excitation energies E* < 26 MeV with the energies of accelerated alpha particles Eα = 27.2 and 67.2 MeV. Three unbound excited levels are observed in the excitation energy interval of 6Li nucleus from 7 to 16 MeV, as well as two excited levels of 6Li with excitation energies of 21.30 and 21.90 MeV, which are consistent with theoretical calculations, but were not reliably confirmed experimentally. The application of the particle decay spectroscopy method made it possible to eliminate some ambiguities in the energy parameters of the excited states of the 6Li nucleus.Item Взаємодiя 𝛼α + t i α + 3He та спектр збуджених станiв ядра 6Li(2025) Поворозник, Орест; Горпинич, Ольга; Рознюк, Ю.; Ячменьов, О.Проведено кiнематично повне дослiдження реакцiй 3He(α, pα)d на ядрах 3He радiогенного походження, накопичених у титан-тритiєвих мiшенях та 3H(α, dα)n, 3H(α, τt)n на ядрах тритiю на цих же мiшенях для вивчення спектра збудження ядра 6Li до енергiй збудження E*< 26 MeВ при енергiї пучкiв прискорених альфа-частинок Eα = 27,2 i 67,2 МеВ. Спостерiгались три незв’язанi збудженi рiвнi в енергетичному дiапазонi енергiї збудження ядра 6Li вiд 7 до 16 МеВ та два збудженi рiвнi 6Li з енергiями збудження 21,30 та 21,90 MeВ, якi узгоджуються з теоретичними розрахунками, але не були достовiрно пiдтвердженi експериментально. Використання методу спектроскопiї розпаду збуджених рiвнiв (particle decay) дозволило усунути деякi неоднозначностi в енергетичних параметрах збуджених станiв ядра 6Li.Item Про застосування форми хвильового фронту альвенових мод для діагностики просторового каналювання(Інститут ядерних досліджень, 2024) Яковенко, ЮрійАнотація до доповіді на XXXI Щорічній науковій конференції Інституту ядерних досліджень НАН України, (м. Київ, 27-31 травня 2024 року). Метою цієї роботи є розробка числових засобів для дослідження такого зв’язку в складніших альвенових власних модах, які не можна задовільно наблизити однією полоїдною гармонікою, – RSAE-модах (Reversed-Shear Alfven Eigenmode) та TAE-модах (Toroidicity-induced Alfven Eigenmode).Item Числове дослідження швидких магнітозвукових мод у токамаках(Інститут ядерних досліджень, 2024) Бурдо, Олена; Колесниченко, Ярослав; Яковенко, Юрій; Руденко, Т.Анотація до доповіді на XXXI Щорічній науковій конференції Інституту ядерних досліджень НАН України, (м. Київ, 27-31 травня 2024 року). У цій доповіді робиться огляд числових кодів, призначених для моделювання FMM з частотами в йонно-циклотронному діапазоні, які було розроблено в останній час авторами.Item Primordial black holes and their gravitational-wave signatures(2025) Bagui, Eleni; Clesse, Sébastien; De Luca, Valerio; Ezquiaga, Jose María ; Franciolini, Gabriele; García-Bellido, Juan; Joana, Cristian; Kumar Jain, Rajeev; Kuroyanagi, Sachiko; Musco, Ilia; Papanikolaou, Theodoros; Raccanelli, Alvise; Renaux-Petel, Sébastien; Riotto, Antonio; Ruiz Morales, Ester; Scalisi, Marco; Sergijenko, Olga; Ünal, Caner; Vennin, Vincent; Wands, DavidIn the recent years, primordial black holes (PBHs) have emerged as one of the most interesting and hotly debated topics in cosmology. Among other possibilities, PBHs could explain both some of the signals from binary black hole mergers observed in gravitational-wave detectors and an important component of the dark matter in the Universe. Significant progress has been achieved both on the theory side and from the point of view of observations, including new models and more accurate calculations of PBH formation, evolution, clustering, merger rates, as well as new astrophysical and cosmological probes. In this work, we review, analyze and combine the latest developments in order to perform end-to-end calculations of the various gravitational-wave signatures of PBHs. Different ways to distinguish PBHs from stellar black holes are emphasized. Finally, we discuss their detectability with LISA, the first planned gravitational-wave observatory in space.Item Cu-Related Paramagnetic Centers in Cu- and (Cu,Y)-Doped ZrO2 Nanopowders(2025) Nosenko, Valentyna; Vorona, Igor; Trachevskyi, Viacheslav; Zagorodniy, Yuriy; Okulov, Sergey; Isaieva, Oksana; Yukhymchuk, Volodymyr; Kulinich, Sergei; Borkovska, Lyudmyla; Khomenkova, LarysaIn this work, we studied Cu-doped and (Cu,Y)-codoped ZrO2 nanopowders produced through a coprecipitation approach to identify the nature of Cu-related bulk and surface paramagnetic centers. We conducted EPR, NMR, and Raman scattering studies on Cu- and (Cu,Y)-doped ZrO2 powders calcined at different temperatures. At low calcination temperatures (400 ◦C) and low Cu loading (0.1–1.0 mol.% of CuO), the EPR signal was found to be attributed to surface-related Cu-H2O complexes. For powders with higher Cu content (up to 8.0 mol.% of CuO), the superparamagnetic signal associated with the formation of copper clusters was observed. At higher calcination temperatures, the destruction of Cu-related surface complexes promotes the incorporation of Cu2+ ions into the bulk of ZrO2 nanocrystals at Zr positions. Co-doping ZrO2 with Cu and Y was observed to facilitate the incorporation of Cu2+ ions into cation sites at lower calcination temperatures when compared with Cu-doped ZrO2.Item Luminophores for luminescent solar concentrators(2024) Rudko, GalynaThe war in Ukraine demonstrated the vulnerability of the energy supply system with centralized power supply. Moreover, it showed that the country must not rely on imported gas and oil, and also highlighted the danger of using nuclear plants. Under these circumstances solar energy gains the acute attention especially because of possibility to decentralize energy production. However, using of traditional solar cells in Ukraine encounters a problem of rather low amount of sunny days thus there is a demand for the devices capable of operating under diffuse illumination.Item Mn2+ як ЕПР зонд для вивчення структури мікро- та нанорозмірних порошків ZnS(2024) Ворона, Ігор; Іщенко, С.; Баран, Н.; Носенко, Валентина; Грачов, В.Матеріали доповіді учасників міжнародного наукового семінару "ЕПР-орієнтири еволюції методології пізнання"Item Радіаційні дефекти в термічно відпаленому карбонатвмісному гідроксилапатиті(2024) Носенко, Валентина; Ворона, Ігор; Іщенко, С.; Окулов, СергійМатеріали доповіді учасників міжнародного наукового семінару "ЕПР-орієнтири еволюції методології пізнання".Item DNA condensation induced by Li+ counterions(2024) Bubon, Tetiana; Piatnytskyi, Dmytro; Perepelytsya, SergiyMaterials of the participants' report of Bogolyubov Kyiv Conference "Problems of Theoretical and Mathematical Physics", dedicated to the 115-th anniversary of the outstanding theoretician in physics and mathematics Mykola BogolyubovItem Effects of metallic and molecular counterions in structural dynamics of the DNA double helix(2024) Perepelytsya, SergiyThe aim of this paper is to derive the hydrodynamics for a cold Bose gas from the microscopic platform based on the many-body Schr¨odinger equation and general assumptions of the hydrodynamic approach (HA) applicable to any dimension.Item To the 115th anniversary of the birth of Mykola Bogolyubov(2024) Zagorodny, A.; Zasenko, V.; Perepelytsya, SergiyMaterials of the participants' report of Bogolyubov Kyiv Conference "Problems of Theoretical and Mathematical Physics", dedicated to the 115-th anniversary of the outstanding theoretician in physics and mathematics Mykola BogolyubovItem Primordial black holes and their gravitational-wave signatures(2023) Bagui, Eleni; Clesse, Sébastien; De Luca, Valerio; Ezquiaga, Jose María; Franciolini, Gabriele; García-Bellido, Juan; Joana, Cristian; Jain, Rajeev Kumar; Kuroyanagi, Sachiko; Musco, Ilia; Papanikolaou, Theodoros; Raccanelli, Alvise; Renaux-Petel, Sébastien; Riotto, Antonio; Morales, Ester Ruiz; Scalisi, Marco; Sergijenko, Olga; Unal, Caner; Vennin, Vincent; Wands, DavidIn the recent years, primordial black holes (PBHs) have emerged as one of the most interesting and hotly debated topics in cosmology. Among other possibilities, PBHs could explain both some of the signals from binary black hole mergers observed in gravitational wave detectors and an important component of the dark matter in the Universe. Significant progress has been achieved both on the theory side and from the point of view of observations, including new models and more accurate calculations of PBH formation, evolution, clustering, merger rates, as well as new astrophysical and cosmological probes. In this work, we review, analyse and combine the latest developments in order to perform end-to-end calculations of the various gravitational wave signatures of PBHs. Different ways to distinguish PBHs from stellar black holes are emphasized. Finally, we discuss their detectability with LISA, the first planned gravitational-wave observatory in space.Item High-Performance Multiwavelength GaNAs Single Nanowire Lasers(2024) Jansson, Mattias; Nosenko, Valentyna; Torigo, Yuto; Nakama, Kaito; Yukimune, Mitsuki; Higo, Akio; Ishikawa, Fumitaro; Chen, Weimin; Buyanova, IrinaIn this study, we report a significant enhancement in the performance of GaNAs-based single nanowire lasersthrough optimization of growth conditions, leading to a lowerlasing threshold and higher operation temperatures. Ouranalysis reveals that these improvements in the laser performance can be attributed to a decrease in the density of localizedstates within the material. Furthermore, we demonstrate thatowing to their excellent nonlinear optical properties, thesenanowires support selffrequency conversion of the stimulatedemission through second harmonic generation (SHG) and sumfrequency generation (SFG), providing coherent light emissionin the cyan-green range. Mode-specific differences in the self-conversion efficiency are revealed and explained by differencesin the light extraction efficiency of the converted light caused by the electric field distribution of the fundamental modes. Ourwork, therefore, facilitates the design and development of multiwavelength coherent light generation and higher-temperatureoperation of GaNAs nanowire lasers, which will be useful in the fields of optical communications, sensing, and nanophotonicsItem Dual-channel SPR biosensor for enhanced glioma relapse diagnostics: Blood cell aggregation as a biomarker for tumor malignancy(2024) Samoylov, Anton; Khristosenko, Roman; Gridina, N.; Dorozinsky, Glib; Romanchuk, V.; Khomenkova, LarysaAbstract. A biosensor based on the surface plasmon resonance (SPR) phenomenon has been developed for the express diagnosis of brain gliomas relapse by assessing blood cell aggregation indicators. The device features two optical channels, allowing for two studies to be performed simultaneously or enabling one channel to be used as a reference. This approach significantly increases biosensor sensitivity by reducing the impact of external factors. The optical excitation source is a p-polarized semiconductor laser with a 650 nm wavelength. The sensing elements were F1 optical glass plates with a refractive index of 1.61, with sputtered layers of chromium (5 nm) and gold (45…50 nm). As a result of the studies, a correlation was ascertained between the level of peripheral blood cell aggregation in patients and the degree of malignancy of gliomas. A statistically significant difference (p ≤ 0.05) was found between the groups of conditionally healthy individuals and those with grade II-IV gliomas. A decrease in the shift of the SPR curve during blood testing indicates an increase in cell aggregation levels and a decrease in their electric charge on membranes. This trend gradually intensifies with the increasing degree of glioma malig-nancy, reaching minimal values in patients with grade IV gliomas, indicating changes in the physicochemical properties of cell membranes and a reduction in their electric charge.Item The 2nd Scientific workshop for students "Computational Physics of DNA"(2024) Perepelytsya, Sergiy; Tetiana, BubonThe article is devoted to the 2nd Scientific workshop for students “Computational physics of DNA”.Item Про можливість створення науково-технічного центру з використання радіаційних технологій у медицині(2024) Поворозник, Орест; Горпинич, ОльгаРозглянуто можливість створення в Інституті ядерних досліджень НАН України науково-технічного підприємства з виробництва широкого спектра радіаційних ізотопів та радіонуклідних фармацевтичних препаратів на їх основі. Наразі в Україні потреба в таких препаратах забезпечується виключно завдяки імпорту. В Інституті є всі передумови для створення такого підприємства: приміщення, пристосовані для проведення радіаційно небезпечних робіт, персонал, який має відповідний досвід з виготовлення експериментальних зразків радіофармпрепаратів, і наявність осіб, які можуть організувати і налагодити виробництво. Наведено огляд прискорювачів і технологій з метою визначення оптимальних для України рішень. Обговорено можливість проведення робіт з пучкової онкотерапії та створення підрозділу бор-нейтрон-захоплювальної терапії на базі низькоенергетичного прискорювача ЕГП-10К.Item Reality conditions for the KdV equation and exact quasi-periodic solutions in finite phase spaces(2024) Bernatska, JuliaIn the present paper reality conditions for quasi-periodic solutions of the KdV equation are determined completely. As a result, solutions in the form of non-linear waves can be plotted and investigated. The full scope of obtaining finite-gap solutions of the KdV equation is presented. It is proven that the multiply periodic }1, 1-function on the Jacobian variety of a hyperelliptic curve of arbitrary genus serves as the finite-gap solution, the genus coincides with the number of gaps. The subspace of the Jacobian variety where }1, 1, as well as other }-functions, are bounded and real-valued is found in any genus. This result covers every finite phase space of the KdV hierarchy, and can be extended to other completely integrable equations. A method of effective computation of this type of solutions is suggested, and illustrated in genera 2 and 3.Item Electronic Spectrum and Conductivity in Graphene with Impurities(2023) Kruchinin, Sergei; Repetsky, Stanislav; Vyshyvana, Iryna; Polishchuk, ArkadiyIn the tight-binding one-electron model, the influence of substitutional impurity atoms on the energy spectrum and electrical conductance of graphene is studied. It is established that the ordering of substitutional impurity atoms on nodes of the crystal lattice causes the appearance of a gap in the energy spectrum of graphene 𝜂|𝛿| in width centered at the point 𝑦𝛿, where 𝜂 is the parameter of ordering, 𝛿 is the difference of the scattering potentials of impurity atoms and carbon atoms, and 𝑦 is the impurity concentration. If the Fermi level is located outside the gap, then the electrical conductance increases with the parameter of order 𝜂. It is shown that an increase in the electrical conductance with the order parameter is a result of both the growth of the density of states at the Fermi level and the time of relaxation of electron states. We have demonstrated the presence of a domain of localized states on the edges of the energy gap arising at the ordering of atoms of the admixture.Item Effect of MgO/ZnO ratio on the formation process of MgxZn1-xO ceramics(2024) Korsunska, Nadiia; Polishchuk, Yuliya; Ponomaryov, Semyon; Kozoriz, K.; Chusnutdinow, S.; Melnichuk, Olexandr; Melnichuk, Lyudmyla; Khomenkova, LarysaThe structural characteristics, chemical composition, and element spatial distribution in MgxZn1-xO ceramics were investigated using X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, energy-dispersive X-ray spectroscopy, and cathodoluminescence techniques. The study revealed that the morphology of the ceramic samples, as well as the mechanism of solid solution formation, depend on the relative contribution of both oxides in the charge. It was discovered that hexagonal and cubic phases of the solid solution were found to form simultaneously. An increase in the MgO content in the charge results in the magnesium content rise in the hexagonal grains continuously, reaching approximately 13 at.%. It was discovered an enrichment of grain boundaries with zinc and magnesium playing a significant role in doping ZnO and MgO grains. Obtained results allowed to propose two mechanisms involved in the formation of solid solution ceramics: i) diffusion of Mg and Zn along grain boundaries, followed by their incorporation into ZnO or MgO grains, respectively, and ii) interdiffusion of Mg into ZnO and Zn into MgO due to direct contact of ZnO and MgO grains. The second mechanism appears to dominate when both ZnO and MgO contribute comparably, increasing the probability of their direct contact. This study significantly advances the understanding of the process of the formation of MgxZn1-xO ceramics under thermodynamic conditions. These insights are crucial for optimizing the doping process and improving the material properties, thereby promoting innovations in the ceramics industry.