BULLETIN OF THE L.N. GUMILYOV EURASIAN NATIONAL UNIVERSITY. PHYSICS. ASTRONOMY SERIES

Inflation and ACT DR6

Кобланды Ержанов — 2026-06-29

The recent data from the Atacama Cosmology Telescope (ACT DR6) has shifted the preferred value of the scalar spectral index to ns = 0.9743±0.0034, placing well-established models such as the Starobinsky potential near the 2σ boundary of the r-ns plane. We address this tension through two approaches. First, we consider the Power-Law Plateau potential within standard Einstein gravity and show that its predictions lie within the 1σ ACT contour for a broad range of the free parameters. Second, we embed the Starobinsky potential within Einstein-Gauss-Bonnet gravity, where the non-minimal coupling between the inflaton and the Gauss-Bonnet term shifts the predictions into the 1σ ACT region for both tanh and exponential coupling functions. In both cases, the running of the scalar spectral index is consistent with the ACT ns-αs contour.

Cosmological parameters of the F(R,T,X,Phi)-gravity model

Кобланды Ержанов — 2026-06-29

In this paper, we study an extended modified F(R,X,Phi) gravity theory applied to the homogeneously isotropic Friedmann–Robertson–Walker metric. Based on the obtained field equations, we analyze the solutions, including additional conditions such as the Monge–Ampère equation. It is shown that for certain parameter values, the model leads to a regime corresponding to the quasi-de Sitter expansion of the Universe. We compare the theoretical results with observational data from the Planck 2018 mission, including the Hubble constant, dark energy density, spectral index, primordial fluctuation amplitude, and the tensor-to-scalar mode ratio. We show that the model is in natural agreement with cosmological observations of both the late and early Universe, providing the suppression of tensor perturbations and the correct spectral tilt. The results obtained confirm the physical consistency and observational compatibility of this modified gravity model.

Engineering Multicomposite Ceramic Systems with Improved Thermal Insulation and γ-Ray Shielding Performance

Vladimir Uglov — 2026-06-29

The article presents the results of complex studies of the assessment of alterations in thermal insulation and shielding characteristics in 1- x(TeO₂ – CeO₂ – WO₃ – ZnO₂ – Bi₂O₃) – xZrO₂ ceramics with variations in the ratio of components during their sintering, which leads to a change in the phase composition. It is determined that the addition of zirconium dioxide to the composition of the main TeO₂ – CeO₂ – WO₃ – ZnO₂ – Bi₂O₃ matrix leads to the formation of a monoclinic phase ZrCeO₂, the increase in the contribution of which is directly proportional to the observed hardening effect, expressed in an elevation in hardness and bending strength. Thermal insulation properties of composite 1- x(TeO₂ – CeO₂ – WO₃ – ZnO₂ – Bi₂O₃) – xZrO₂ ceramics were studied depending on the variation of the zirconium dioxide component in the composition, the addition of which changes the strength and thermal insulation properties. During the experiments, it was established that a growth in the monoclinic ZrCeO₂ substitution phase in the composition of ceramics leads to a rise in the difference in temperatures on the front and back sides, which indicates an enhancement in thermal insulation properties, a growth in the temperature difference, which is due to the low thermal conductivity of zirconium dioxide. A general analysis of the shielding characteristics showed a positive effect of the formation of the ZrCeO₂ phase on the shielding efficiency, allowing the absorption capacity of ceramics to be increased by 10 – 15 %, while the resulting ceramics have high strength and thermal insulation properties.

Трансуран ядроларының спонтанды бөліну қасиеттерін зерттеу үшін газ толтырылған GRAND сепараторының фокальді жазықтығында SFiNx детекторлық жүйесін қолдану

Бекзат Сайлаубеков — 2026-06-29

Біріккен ядролық зерттеулер институтында (БЯЗИ) ауыр спонтанды бөлінетін ядролардың синтезі және олардың ыдырау сипаттамаларын зерттеу саласында көпжылдық тәжірибе жинақталған. Осы зерттеулердің мүмкіндіктерін кеңейту үшін Аса ауыр элементтер фабрикасы (ААЭФ) құрылды, оның негізгі элементі жоғары қарқынды сәулелермен жұмыс істеуге оңтайландырылған DGFRS-2 газ толтырылған сепараторы болып табылады. ДЦ-280 үдеткішін DGFRS-2 сепараторымен бірге қолдану соңғы жылдары трансурандық нысаналармен бірқатар сәтті тәжірибелер жүргізуге мүмкіндік берді. Қондырғының жоғары тиімділігі рекордтық қысқа мерзімде (шамамен бір ай) ААЭ изотоптарының ыдырауының 100 оқиғасына дейін тіркелуімен расталды, бұл өте аз қималар жағдайында айтарлықтай жетістік болып табылады.

DGFRS-2 сепараторының сәтті пайдаланылуы GRAND әмбебап газ толтырылған сепараторының жобасын әзірлеуге негіз болды, оның фокальді жазықтығына SFiNx детекторлық жүйесін орналастыру жоспарлануда.

Бұл мақалада негізгі назар трансуран ядроларының спонтанды бөліну қасиеттерін зерттеу үшін қолданылған тәжірибе әдістемесіне және GRAND сепараторында SFiNx жүйесін пайдалану перспективаларына аударылған. GRAND сепараторында жүргізілген сынақ тәжірибелерінің және SHELS сепараторында SFiNx детекторлық жүйесін қолдана отырып жүргізілген тәжірибелердің нәтижелері ұсынылған. Осы жүйені ААЭФ инфрақұрылымына енгізу мүмкіндіктері қарастырылуда. Ұсынылып отырған әдістеменің басты артықшылығы — бөлінудің лездік нейтрондарын тіркеу мүмкіндігі, бұл ауыр және аса ауыр ядролардың спонтанды бөліну нейтрондарының еселігін өлшеу бойынша тәжірибелерді жоспарлау үшін жаңа мүмкіндіктер ашады. Жасалған тәжірибелік әдістер осы саладағы болашақ зерттеулер үшін елеулі әлеуетке ие.

Multiphase lithium-containing ceramics based on Li2TiO3, Li2ZrO3, Li2MoO4: synthesis, structure, and strengthening

Ainagul Khametova — 2026-06-29

The influence of the formation of two- and three-phase lithium-containing ceramics based on Li₂TiO₃, Li₂ZrO₃ and Li₂MoO₄on their structural and mechanical properties was investigated in the context of their application in tritium breeding systems. The aim of the study was to evaluate the possibility of enhancing the mechanical stability of lithium-containing ceramics by controlling the phase composition and implementing interphase strengthening mechanisms.

Multiphase ceramic materials were synthesized using a mechanochemical solid-state method followed by thermal treatment at 700 °C. The phase composition and degree of crystallinity of the samples were analyzed by X-ray diffraction, while the mechanical properties were evaluated by assessing the resistance to uniaxial compression. It was shown that the applied synthesis route provides the formation of ceramics with a high degree of crystallinity and a stable phase composition.

It was established that variation of the phase ratio leads to an increase in the critical fracture load under uniaxial compression of two-phase ceramics by more than 1.5 times compared to single-phase materials, while the introduction of Li₂MoO₄provides an additional increase of this parameter for three-phase ceramics (up to 1.5–1.6 times relative to two-phase materials). The obtained results demonstrate the potential of multiphase lithium-containing ceramics for application in blanket systems of thermonuclear reactors.

Hamiltonian formalism of periodic collisionless motion of particles in a field

Ардак Жавлиева — 2026-06-29

The paper presents a Hamiltonian formalism of the motion of gravitational particles without collisions in a flat and self-consistent field. The field of the system is represented as a potential well, the depth and length of which are expressed by energy and pressure. It was shown that the particles in the well accumulate in the boundary, forming separate concentric regions. The two-stream periodic motion of non-relativistic gravitating particles of the system was considered on the basis of the continuity equation. Using the Poisson equation, it was proved that the concentration of non-colliding particles is directly proportional to the gravitational potential. It was also shown that the static equilibrium between the two-flow periodic motion of particles and a self-consistent field can be described using the Poisson equation. Based on the conservation law, it was proved that the Hamiltonian function for particle interactions with a field is the total pressure as the first integral, and the mathematical nature of the Bernoulli force was determined. According to the conditions of the state and the spatial scale of the system, integral curves passing through the origin and the law of spatial potential distribution are determined. It is proved that the law of variation of velocity, pressure and concentration of particles along the length of the system is fulfilled at certain values of the state parameter. The results of theoretical calculations were presented in a simplified form. It was shown that, depending on the values of the state parameter of a two-stream system, the field of the system has the forms of a potential pit and a gap.

Photoelectrochemical Pathways to Green Hydrogen: Analysis, Review, and Foresight

Бекболат Сейтов — 2026-06-29

The current dynamics of decarbonization reveal structural limitations of existing hydrogen production models. Techno-economic assessments indicate that energy consumption remains the primary factor determining the cost of green hydrogen, while the pace of electrolyzer capacity expansion remains insufficient compared with the trajectories required to achieve carbon neutrality. Despite the increase in installed electrolyzer capacity from approximately 0.1 GW in 2020 to about 1.75 GW in 2023, a significant share of announced projects has not reached the stage of final investment decision, and infrastructure constraints persist.

Photoelectrochemical water splitting represents an alternative configuration that integrates semiconductor light absorption and electrochemical water splitting within a single system. Unlike centralized electrolysis schemes that require developed logistics for hydrogen storage and transportation, PEC architectures enable localized hydrogen generation, thereby reducing supply-chain vulnerabilities highlighted in studies on hydrogen infrastructure reliability.

This study presents a systematic analysis of the evolution of PEC technologies by integrating materials science data, bibliometric indicators, and patent activity dynamics. The relationship between threshold values of solar-to-hydrogen efficiency, material stability limitations, and the innovation trajectories of oxide, nitride, chalcogenide, and hybrid photoelectrodes is examined. A prospective roadmap to 2035 is proposed, emphasizing strategies for replacing noble metals, compatibility with industrial manufacturing, and integration into distributed hydrogen infrastructure. PEC is considered a long-term complementary technology within the emerging architecture of the hydrogen energy system.

- Analysis of modern requirements supported by Fiber Bragg Grating (FBG) sensors in space infrastructure

Нуржигит Смайлов — 2026-06-29

This article is aimed at analyzing modern methods based on Fiber Bragg Grating (FBG) sensors for structural health monitoring of space infrastructure. The space environment, characterized by radiation exposure, wide temperature fluctuations, and mechanical loads, requires highly accurate and long-term monitoring of even minimal deformations.

The study examines the operating principle of FBG sensors, the variation of the Bragg wavelength under the influence of strain and temperature, as well as the impact of ionizing radiation on measurement stability. Three main approaches are proposed: the use of radiation-resistant FBG sensors, real-time monitoring using multiplexed sensor networks, and optimal placement of sensors in regions of maximum deformation combined with intelligent data processing.

The results of the analysis show that the integrated application of these methods ensures high measurement accuracy with a minimal number of sensors, reduces system weight and complexity, and enhances the long-term reliability of space structures.

Исследование ионной проводимости с-ZrO2, стабилизированного СаO и Y2O3 методом ТФП

guldari bairbayeva — 2026-06-29

In this work, the migration of oxygen ions in cubic zirconium dioxide stabilized with CaO and Y₂O₃ impurities was studied using density functional theory with the B3LYP hybrid functional. The effect of the concentration of substituting atoms on the migration energy of an oxygen ion was considered. It was shown that the introduction of impurity cations significantly reduces the migration energy, which contributes to an increase in ionic conductivity. It was established that the most favorable conditions for oxygen-ion transport are realized in yttrium-stabilized configurations. The obtained results are important for the targeted design of solid oxide electrolytes based on ZrO₂ with improved transport properties.

ТЕОРЕТИЧЕСКИЙ ОБЗОР ПЕРЕНОСА ПРОТОНОВ В КОМПОЗИТНЫХ МЕМБРАНАХ MOF-5/ПОЛИМЕР/ГЛУБОКОЭВТЕКТИЧЕСКИЙ РАСТВОРИТЕЛЬ: ВЗАИМОСВЯЗЬ СТРУКТУРЫ И СВОЙСТВ

Assem Temirbayeva — 2026-06-29

Proton-exchange membranes (PEMs) play a crucial role in the operation of fuel cells; however, their performance is often limited by strong hydration dependence, reduced proton conductivity at elevated temperatures, and decreased stability under low-humidity conditions. This paper presents a theoretical review and literature analysis of proton transport in MOF-5/polymer/deep eutectic solvent (DES) composite systems. Particular attention is given to published studies employing density functional theory (DFT) and molecular dynamics (MD) methods to explain the electronic, structural, and dynamic factors governing proton transport.

Analysis of the reported literature data indicates that the incorporation of DES into MOF–polymer membranes may promote charge redistribution, formation of extended hydrogen-bond networks, and reduction of proton-transfer energy barriers. At the molecular level, DES is considered a functional medium capable of supporting dynamic hydrogen-bonded transport channels, while MOF-5 provides nanoscale confinement and may direct proton carrier migration within the porous structure.

Thus, the generalization of published literature data allows the establishment of relationships between structural organization, interfacial interactions, and proton conductivity in MOF–polymer–DES composite membranes. The reviewed approaches may serve as a basis for the rational design of next-generation proton-exchange membranes with improved transport and operational properties.

DFT исследование гибридной структуры BaTiO3/g-C3N4

Gulbanu Kaptagay — 2026-06-29

Annotation. In recent decades, carbon graphite nitride (g-C₃N₄), a bimetallic polymer organic semiconductor with tri-s-triazine units, has been a promising research topic due to its optimal photocatalytic properties and unique characteristics such as a suitable band structure, visible light absorption activity, and high chemical and thermal stability. However, the photocatalytic efficiency of pure g-C₃N₄ limits its use in photocatalytic systems due to the high recombination rate of photogenerated charges, insufficient light absorption, and small specific surface area. The combination of graphite carbon nitride with perovskites provides a good opportunity to correct these deficiencies. In this study, the theoretical modeling of the g-C₃N₄/BaTiO₃ hybrid structure was considered. A (100) surface was created from the cubic phase of barium titanate. For (100) BaTiO₃ surfaces, it was found that a TiO₂-terminated surface is more thermodynamically favorable. The relaxation process of the hybrid structure was investigated. The developed interface is thermodynamically stable, which provides prerequisites for its further application for photogeneration of energy in various processes based on redox reactions. Тhermodynamic stability of the BaTiO₃/g-C₃N₄ nanocomposite can be explained by the interaction of BaTiO₃nanoparticles with g-C₃N₄through the Ti-N bond, a decrease in the band gap due to the introduction of hybridized states leading to increased absorption in the visible range, and a large surface area that provides more active sites for effective light absorption.

ІІІ-ші және V-ші мұз күйлерінің серпімділік қасиеттеріне температура мен қысымның әсерін зерттеу

Эльмира Мадалиева — 2026-06-29

Мақалада алғаш рет екі рет дистилляцияланған судан кристаллданып, жоғары (2,50-9,00)кбар қысым аралығындағы 250К, 230К, 210К, 190К температуралардағы серпімді қума, көлденең, толқындардың орташа жылдамдықтарының шамалары тәжірибелік зерттеулер жүргізу арқылы анықталды.

Соным қатар мұздың ІІІ-ші және В-ші түрлеріндегі келтірілген және Дебайдың сипаттамалық температура оларда тарайтын ультрадыс толқындарының орташа жылдамдықтарын пайдалану арқылы есептелген.

Зерттеу жұмыстарын жүргі атында (0-25)кбар қысым және (90-250)К температура алалығында жұмыс істейтін поршень-цилиндр типа үшқабатты камеры жинастырдық. Камераның бөлшектері термоөңделген инструмента Р18(HRC=60÷62), Х12М(HRC=58÷60), Х12М(HRC=48÷50) құрыштардан тұрады. Камера, которую они используют, оснащена азотом суытылды. Камерада орналасқан зерттелелетин үлгінің температура мен қысымың ішінде орналасқан они мыс-константан терможұбында пайда болатын кернеуді және (Sn) қалайы мен (Ga) галий өткізгіштерінің электр кедергілерин өлшей арқылы иске асырылды. Мұз көлемінің өзгерістерін поршеннің илгермелі қозғалысын электр импульстеріне айналдыратын арнайы түрлендіргішпен бақылап отырдық. Үлгілердегі қума және көлденең толқындардың жылдамдығы ультрадыбыстық импульстик қондырғының көмегімен өлшенді. Зерттеу барысинда өзгеріске ұшырайтын физикалық параметрер автоматы түрде қадағаланды. Зерттелген үлгі мен камның қабырғасының арасындағы үйкеліс күшін кеміту және ІІІ-ші және В-ші мұз түрлеріндегі қысымды біртектіге жақындату үшінт сырыты графикен атыжаллған вторпластан жасалған ұяшықты пайдаландық.

Elastic scattering of a deuteron on a 12C nucleus at an energy of 35 MeV

Kairat Mendibayev — 2026-06-29

Abstract.

This paper presents the results of measuring the angular distributions of differential cross sections for elastic scattering of deuterons on ¹²C nuclei at an energy of 35 MeV. The experiment was conducted at the K130 accelerator complex (Accelerator Laboratory of the University of Jyväskylä, Finland) using silicon ΔE-E telescopes, which ensure reliable identification of reaction products. The obtained data were analyzed within the framework of an optical model using global parameterizations of the optical potential and double folding potential. It is shown that standard parameterizations generally reproduce the main features of the angular distributions; however, they require refinement to adequately describe the data in the large-angle region. The analysis allowed us to determine the parameters of the effective interaction for the d + ¹²C system at an energy of 35 MeV and estimate the contribution of the imaginary part of the potential to absorption processes. The obtained results can be used in further studies of inelastic processes and nucleon transfer reactions involving deuterons, as well as in constructing consistent models of nuclear interactions.

7Li ядросының 12С ядросымен серпімді әсерлесуінің эксперименттік нәтижелері мен теориялық талдау жолдарына шолу

Baglan Balabekov — 2026-06-29

The ⁷Li + ¹²C system is a key case for exploring nuclear interactions, cluster structures, and reaction mechanisms of light nuclei. Experimental and theoretical studies by Poling (1972), Schumacher (1973), Vineyard (1984), Katori (1988), Nadasen (1995), Parkar (2007), and Jun (2010) revealed distinct energy-dependent features: Coulomb dominance and parameter ambiguities at low energies, diffraction minima and breakup effects at intermediate energies, unique optical potentials at high energies, and fusion processes near the barrier. This review consolidates the available data, traces their evolution, and highlights the role of ⁷Li elastic scattering in understanding nuclear structure and astrophysical lithium abundance problems.

The effect of mechanochemical activation and annealing on the structure and morphology of the WO₃–NiO system

Milana Saidullayeva — 2026-06-29

The present work investigates the processes of phase formation and morphological evolution in the WO₃–NiO system during mechanochemical synthesis followed by thermal annealing. The aim of the study was to determine the influence of milling time and annealing temperature on the phase composition and morphological characteristics of the materials, as well as to identify the conditions for the formation of nickel tungstate (NiWO₄).

The study was carried out using X-ray diffraction analysis, Raman spectroscopy, and scanning electron microscopy. It was shown that variations in milling time do not lead to phase transformations and are accompanied by preservation of a stable phase composition. Raman spectroscopy of non-annealed samples confirmed the presence of the monoclinic WO₃ phase. It was established that thermal annealing at temperatures of 500 °C and above results in the formation of the NiWO₄ phase.

Morphological studies revealed that the initial powders consist of large agglomerates of spherical nanoparticles. At 500 °C, a significant change in morphology and predominance of the NiWO₄ phase with NiO inclusions are observed, whereas further increase in annealing temperature promotes grain growth and enhanced structural ordering. At 1000 °C, large spherical grains with dendrite-like outgrowths are formed.

The obtained results expand the understanding of transition metal tungstate formation mechanisms and may be applied in the development of functional oxide materials for catalytic, photocatalytic, and energy-related applications.

The role of variation of the stabilizing magnesium oxide dopant on phase transformations in the composition of ZrO2 – CeO2 ceramics

Artem Kozlovskiy — 2026-06-29

The aim of this work is to determine the role of the addition of a stabilizing magnesium oxide dopant to the composition of composite ZrO₂ – CeO₂ ceramics in changing the kinetics of phase transformations that occur during high-temperature sintering of ceramics depending on the variation in the concentration of the dopant. According to the assessment of the microstructural features of ZrO₂ – CeO₂ ceramics, it was found that the addition of MgO in low concentrations leads to the formation of finely dispersed grains of a globular shape that are tightly packed, while an increase in the concentration of MgO above 0.05 M leads to an enlargement of the grains and a change in their shape from globular to polyhedral with the formation of MgO inclusions, the presence of which is due to exceeding the solubility limit of magnesium oxide in the ZrO₂ – CeO₂ matrix. It has been established that variation in the MgO content allows for effective control of the morphology of ZrO₂ – CeO₂ ceramics from a loose porous structure to a dense fine-grained heterogeneous system with controlled grain size, high defectivity and developed intergranular boundaries. Using X-ray phase analysis methods, it was established that the introduction of MgO leads to a restructuring of the phase composition: from the initial two-phase state to a single-phase cubic structure at 0.01 M MgO and the subsequent formation of a mixture of two cubic and tetragonal phases at higher concentrations with the dominance of the cubic phase in the composition.

Assessment of Radioactive Lead Isotopes in the Environment of Kazakhstan

Айгерим Муса — 2026-06-29

The industry of Kazakhstan, including the combustion of high-ash coal, uranium mining and processing, non-ferrous metallurgy, oil production, and the consequences of nuclear weapons testing, creates a unique environment for the occurrence of radioactive lead isotopes. Unlike stable lead isotopes commonly used for source apportionment of pollution, the radioactive isotopes ²¹⁰Pb (T_1/2 = 22.3 years), ²¹²Pb (T_1/2= 10.6 hours), and ²¹⁴Pb (T_1/2= 26.8 minutes) are directly associated with the release of radon (²²²Rn) and thoron (²²⁰Rn), as well as aerosol dynamics, making them excellent indicators of both natural and technologically enhanced radiation exposure. This study represents the first attempt to assess the comprehensive distribution of radioactive lead isotopes in atmospheric aerosols, soils, and waters of Kazakhstan and their contribution to the global environment.

The study identified several major gaps requiring further investigation: (1) the absence of a nationwide spatial inventory of ²¹⁰Pb in air and soil; (2) the lack of any measurements of ²¹²Pb and ²¹⁴Pb near coal-fired power plants and uranium tailings; and (3) the unknown chemical forms (bioavailability) of ²¹⁰Pb in emission plumes. Specific recommendations are proposed to address each of these gaps.