http://repository.enu.kz/handle/enu/15475 2026-04-06T04:34:59Z http://repository.enu.kz/handle/enu/30979 Theoretical probes of Higgs boson-axion nonperturbative couplings Oikonomou, V. K. In this work we investigate the phenomenological implications of several nontrivial Higgs-boson- axion couplings, which cover most of the possible nonperturbative scenarios. Specifically we consider the combination of having higher-order nonrenormalizable Higgs-boson-axion couplings originating from a weakly coupled effective theory combined with nonperturbative couplings of the form ∼ϵΛc2|H|2cos(φfa). Since we consider the misalignment axion, the nonperturbative couplings can be expanded in the form of a perturbation expansion in powers of φ/fa, thus after the electroweak symmetry breaking, the effective potential of the axion is drastically affected by these terms. We investigate the phenomenological implications of these terms for various values of the mass scale Λc, and some scenarios are theoretically disfavored, while other scenarios with nonperturbative Higgs-boson-axion couplings of the form ∼ϵΛc2|H|2cos(φfa) with Λc∼10-10×ma and ma∼10-10 eV, lead to a characteristic pattern in the stochastic gravitational wave background via the deformation of the background equation of state parameter occurring at frequencies probed by the Einstein Telescope. We also consider loop effects from the Higgs sector caused by the term ∼ϵΛc2|H|2cos(φfa) if we close the Higgs in one loop. 2024-01-01T00:00:00Z http://repository.enu.kz/handle/enu/30978 The Influence of Variations in Synthesis Conditions on the Phase Composition, Strength and Shielding Characteristics of CuBi2O4 Films Kadyrzhanov, Dauren B.; Idinov, Medet T.; Shlimas, Dmitriy I.; Kozlovskiy, Artem L. This paper presents the results of the influence of variation of the synthesis conditions of CuBi/CuBi2O4 films with a change in the applied potential difference, as well as a change in electrolyte solutions (in the case of adding cobalt or nickel sulfates to the electrolyte solution) on changes in the phase composition, structural parameters and strength characteristics of films obtained using the electrochemical deposition method. During the experiments, it was found that, in the case of the addition of cobalt or nickel to the electrolyte solutions, the formation of films with a spinel-type tetragonal CuBi2O4 phase is observed. In this case, a growth in the applied potential difference leads to the substitution of copper with cobalt (nickel), which in turn leads to an increase in the structural ordering degree. It should be noted that, during the formation of CuBi/CuBi2O4 films from solution–electrolyte №1, the formation of the CuBi2O4 phase is observed only with an applied potential difference of 4.0 V, while the addition of cobalt or nickel sulfates to the electrolyte solution results in the formation of the tetragonal CuBi2O4 phase over the entire range of the applied potential difference (from 2.0 to 4.0 V). Studies have been carried out on the strength and tribological characteristics of synthesized films depending on the conditions of their production. It has been established that the addition of cobalt or nickel sulfates to electrolyte solutions leads to an increase in the strength of the resulting films from 20 to 80%, depending on the production conditions (with variations in the applied potential difference). During the studies, it was established that substitution of copper with cobalt or nickel in the composition of CuBi2O4 films results in a rise in the shielding efficiency of low-energy gamma radiation by 3.0–4.0 times in comparison with copper films, and 1.5–2.0 times for high-energy gamma rays, in which case the decrease in efficiency is due to differences in the mechanisms of interaction of gamma quanta, as well as the occurrence of secondary radiation as a result of the formation of electron–positron pairs and the Compton effect. 2024-01-01T00:00:00Z http://repository.enu.kz/handle/enu/30977 THE EFFICIENCY DEPENDANCE OF A SINGLE-CIRCUIT POWER UNIT WITH A HELIUM-COOLED REACTOR AND A HYDROGEN MODULE ON THE DEGREE OF REGENERATION Nurym, K.A.; Antonova, A.M.; Sakipov, K.E.; Vorobyev, A.V.; Stetsov, N.V. The most attractive single-circuit scheme of the power unit was chosen. Helium at the outlet of the reactor core enters the steam generator, where it gives part of the heat to generate highly superheated steam for the electrolysis plant. Next, helium operates in a closed gas turbine cycle with heat recovery. A gas-cooled reactor with a turbine and compressor allows the use of a thermodynamic cycle with high efficiency. A series of design calculations of the regenerator for various degrees of regeneration have been performed. A series of assessments of the effect on the real resistance of the regenerator from the high- and low-pressure sides have been carried out. The thermal scheme of energy production is calculated in accordance with a series of design calculations of the regenerator. 2025-01-01T00:00:00Z http://repository.enu.kz/handle/enu/30976 The Effect of 147 MeV 84Kr and 24.5 MeV 14N Ions Irradiation on the Optical Absorption, Luminescence, Raman Spectra and Surface of BaFBr Crystals Akilbekov, Abdirash; Kenbayev, Daurzhan; Dauletbekova, Alma; Shalaev, Alexey; Akylbekova, Aiman; Aralbayeva, Gulnara; Baimukhanov, Zein; Baizhumanov, Muratbek; Elsts, Edgars; Popov, Anatoli I. Today, BaFBr crystals activated by europium ions are used as detectors that store absorbed energy in metastable centers. In these materials, the image created by X-ray irradiation remains stable in the dark for long periods at room temperature. As a result, memory image plates are created, and they are extended to other types of ionizing radiation as well. Despite significant progress towards X-ray storage and readout of information, the mechanisms of these processes have not been fully identified to date, which has hindered the efficiency of this class of phosphors. In this study, using photoluminescence (PL), optical absorption (OA), Raman spectroscopy (RS), and atomic force microscopy (AFM), the luminescence of oxygen vacancy defects to BaFBr crystals irradiated with 147 MeV 84Kr and 24.5 MeV 14N ions at 300 K to fluences (1010–1014) ion/cm2 was investigated. BaFBr crystals were grown by the Shteber method on a special device. Energy-dispersive X-ray spectroscopy (EDX) analysis revealed the presence of Ba, Br, F, and O. The effect of oxygen impurities present in the studied crystals was considered. The analysis of the complex PL band, depending on the fluence and type of ions, showed the formation of three types of oxygen vacancy defects. Macrodefects (tracks) and aggregates significantly influence the luminescence of oxygen vacancy defects. The creation of hillocks and tracks in BaFBr crystals irradiated with 147 MeV 84Kr ions is shown for the first time. Raman spectra analysis confirmed that BaFBr crystals were amorphized by 147 MeV 84Kr ions due to track overlap, in contrast to samples irradiated with 24.5 MeV 14N ions. Raman and absorption spectra demonstrated the formation of hole and electron aggregate centers upon swift heavy ions irradiation. 2024-01-01T00:00:00Z