The aim of this work is to study the structural, dielectric, and mechanical properties of aluminum oxide ceramics with the triple sintering additive 4CuO-TiO₂-2Nb₂O₅. With an increase in sintering temperature from 1050 to 1500 °C, the average grain size and the microhardness value at a load of 100 N (HV0.1) increased with increasing density. It has been shown that at a sintering temperature of 1300 °C, the addition of a 4CuO-TiO₂-2Nb₂O₅ additive increases the low-frequency permittivity (2–500 Hz) in alumina ceramic by more than an order of magnitude due to the presence of a quadruple perovskite phase. At the same time, the density of such ceramics reached 89% of the theoretical density of α-Al₂O₃, and the microhardness value HV0.1 was 1344. It was observed that the introduction of 5 wt.% 4CuO-TiO₂-2Nb₂O₅ in the raw mixture remarkably increases values of shrinkage and density of sintered ceramics. Overall, the results of this work confirmed that introducing the 4CuO-TiO₂-2Nb₂O₅ sintering additive in the standard solid-phase ceramics route can significantly reduce the processing temperature of alumina ceramics, even when micron-sized powders are used as a starting material. The obtained samples demonstrated the potential of α-Al₂O₃ with the triple additive in such applications as electronics, microwave technology, and nuclear power engineering.

This study examines the equilibrium structure and stability of white dwarfs, incorporating both isotropic and anisotropic pressure distributions. The Tolman–Oppenheimer–Volkoff (TOV) equation is numerically solved using the Chandrasekhar equation of state (EoS) to analyze the effects of pressure anisotropy. A general anisotropy function is introduced to close and solve the system of differential equations. The results indicate that anisotropy remains negligible at the center and increases toward the stellar surface. Stability is assessed using the speed of sound criterion, $v_s^2=dp/d\rho$, and the Buchdahl bound, $2M/R<8/9$, confirming that white dwarfs remain within stability limits. We performed a sensitivity analysis to examine how variations in the anisotropy parameter ${\alpha }_0$ and central density affect the mass, radius, and compactness of white dwarfs. Additionally, we calculated the gravitational redshift at the stellar surface and found that it varies with anisotropy, ranging from $z_s\sim 3.15\times {10}^{-3}$ in isotropic cases to $z_s\sim 0.2\times {10}^{-3}$ in highly anisotropic models. These results link anisotropy to potentially observable features. The findings suggest that while anisotropy does not significantly affect the overall equilibrium structure, it may play a role in astrophysical scenarios involving strong magnetic fields, rotational deformations, or accretion processes in binary systems.

The angular distributions of the elastic and inelastic scattering of α-particles on ¹⁰B nuclei were measured at an energy of 29 MeV (with excitation of the 0.718 MeV (1⁺) state). The data obtained by us, together with the angular distributions of the elastic scattering measured earlier in a wide range of energies from 24 to 90 MeV, were described using an optical model, the coupled-channel method, and parameterized phase analysis. The optimal parameters of optical potentials were found, and a good description of the experimental data in the specified energy range of α-particles was achieved. By taking into account the contribution of the elastic transfer mechanism of the ⁶Li cluster, it was possible to correctly reproduce the rise of the cross section at the backward angles in the elastic channel. The value of the quadrupole deformation parameter was extracted from the analysis of inelastic scattering using the coupled-channel method. The geometric parameters of the interaction potentials were determined using parameterized phase analysis. The radii of the ¹⁰B nuclei in the high-energy region (30 MeV and above) obtained by PPA are in good agreement with the radii calculated in the framework of the optical model.

В статье представлены результаты характеризации тонких пленок на основе CuBi₂O₄ полученных с применением метода электрохимического осаждения при вариации разности прикладываемых потенциалов. Выбор метода электрохимического осаждения для получения тонкопленочных покрытий, обусловлен возможностями получения пленок на практически любых поверхностях, имеющих различную морфологию и геометрию, а также возможностями масштабирования в случае необходимости нанесения покрытий на большие площади. Согласно полученных данным рентгеновской дифракции было установлено, использование выбранных растворов для осаждения, позволяет получать высокоупорядоченные кристаллические пленки CuBi₂O₄ с тетрагональной фазой. При этом вариация разности прикладываемых потенциалов не приводит к формированию примесных фаз или значительных структурных изменений, связанных с переориентаций или процессами рекристаллизации. В ходе проведенных исследований установлено, что вариация условий синтеза приводит к упрочнению покрытий, связанному изменением морфологических особенностей, а также плотности формируемых покрытий. Анализ экранирующих характеристик показал, что использование тонких CuBi₂O₄ покрытий, толщиной 1.5 – 1.6 мкм позволяет снизить эффективность рентгеновского излучения в 2.5 – 3 раза. При этом в случае CuBi₂O₄ покрытий, полученных при разности потенциалов 3.5 В эффективность снижения интенсивности рентгеновского излучения составляет более 80 % от начального значения.

This study substantiates the processing parameters for manufacturing domestic ceramic proppants designed to enhance well production rates during the development of tight oil reserves (TOR) in the Republic of Kazakhstan, where over 70% of geological reserves require multi-stage hydraulic fracturing (MSHF). A comprehensive mineralogical and geochemical analysis of the aluminosilicate base from the "Soyuznoye", "Arkalykskoye", and "Krasnooktyabrskoye" deposits was performed. The scientific novelty lies in the theoretical substantiation of the mechanism driving accelerated mullitization and suppressing destructive cristobalite crystallization via the addition of fluorine-containing modifiers. The obtained results demonstrate that thermochemical modification reduces silicate formation and sintering temperatures to 1250–1400 °C while increasing the mullite phase concentration to 78–85%. According to structural models and literature analogues, the optimized matrix guarantees targeted mechanical properties: crush resistance up to 86 MPa at a minimal open porosity of 0.5–2.0%. The practical significance of the research consists in formulating recommendations for import substitution and localizing medium-to-high-strength proppant manufacturing lines within Kazakhstan, aiming to reduce oilfield service costs and implement a "just-in-time" logistics framework.

The results of the study of intracrystalline electric and magnetic fields in samples on 57Fe nuclei by the ultrafine method of the Mossbauer effect are considered. The source of gamma radiation was 57Co in the chromium matrix. The spectra of the samples were measured on 57Fe nuclei using the MS1104Em spectrometer in the mode of constant accelerations at room temperature for absorption. The crystal structure, phase composition, and electronic states of individual components of the proppants are given. The measurements were carried out on the d8 Advance universal complex (Bruker, Germany). The data of parameters recorded on detectors of secondary energy characteristics of X-rays corresponding to K, L, M, N and O levels of electronic transitions using computer processing of elemental compositions and their ratios in samples are analyzed. The data of X-ray studies of the composition of fly ash are presented, determining its potential application in various industries, including the production of proppants. The results of the analysis of the chemical composition of bauxite samples obtained by X-ray diffraction analysis are presented. The silicon modulus (µSi) has been determined, which is the ratio of Al2O3 to SiO2 to characterize the quality of bauxite. The main components of bauxite were Al2O3 (aluminum oxide) and SiO2 (silicon dioxide). A significant content of Fe2O3 (iron oxide) was also noted, which is 24-33 wt. % for bauxite.