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Summary: The nature of the interaction in the ????????????????−???????????????? quasibinary section was studied, the solubility region of ???????????????? in ???????????????? was determined, ????????????????????1−???????????? solid solutions were obtained, complex physicochemical analyses were carried out and crystal parameters of the sample were determined. The specific electrical conductivity, Hall coefficient, and magnetic resistance of ????????????????????1−???????????? solid solutions were studied in the temperature range of 300-650 K, and the charge transport mechanisms were investigated. The dependence of magnetic resistance on composition, temperature, and magnetic field intensity was studied. The chemical bond and crystallization type structure in Tin monoselenide has also been investigated. Using a special X-ray diffractometer, the X-ray structural analysis was carried.

Summary: In this study, silver nanoparticles (AgNPs) were synthesized via chemical reduction. Then Ag-Ag2S core-shell structures were synthesized by simply mixing different concentrations of Na2S aqueous solution (5,10 and 15mM) and AgNPs. The structural and optical properties of these structures were analyzed. Changes in the structure of the samples were analyzed by X-ray diffraction (XRD). The optical properties and bandgap values were studied using ultraviolet-visible (UV-Vis) spectroscopy. The structural and optical properties of AgNPs revealed clear differences in their physical properties after sulfidation. From the study of optical properties, we determined that Ag-Ag2S core-shell structures have broadband absorption properties that can be controlled by changing the concentration of sulfur ions in the sulfidation process. Also, because of sulfidation, it was determined that the value of the bandgap of Ag-Ag2S structures changes.

Summary: Rubiscolin molecules belong to the class of opioids derived from food substances. To understand the various physiological functions they perform, to target them purposefully, and to synthesize artificial analogs that perform specific functions of the natural molecule, it is necessary to study their three-dimensional spatial structures. The spatial structures of rubiscolin molecules and their analogs were investigated using theoretical conformational analysis methods. The potential energy of the molecule was chosen as the sum of non-valent, electrostatic, torsion interaction energies and hydrogen bond energies. The spatial structures of [Ile3]- and [Phe3]-rubiskolin-5 molecules were studied in the context of the low-energy conformations of the natural rubiscolin molecule. The calculations revealed that the solid structure of both analogs is represented by eight lowenergy conformations, similar to those of the natural rubiskolin-5 molecule. It has been shown that the energy and geometric parameters of the molecules in both analogues are the same as in the natural rubiscolin-5 molecule, therefore it is not advisable to propose to synthesize both artificial analogues.

Summary: K0,945Rb0,055NO3 monocrystals were grown from aqueous solutions of KNO3 and RbNO3 by isothermal crystallization method and the morphology of crystal growth during III phase transformations in these crystals was studied by optical microscopy. It was determined that two polymorphic transformations occur in the studied crystal from room temperature to the melting temperature. The structural transformations in these crystals are enantiotropic and of the monocrystal-monocrystal type. The equilibrium temperature between the interconverting II and I modifications is T=4550.5K. In the investigated sample, a repeated III phase transformation was studied, and the growth of the process was observed in a mono-nucleated manner in the 001 crystallographic direction. This transformation was accompanied by the movement of the non-linear boundary separating the phases. The transformation rate is as 〖2−????[001]>1−????[001]. Experiments show that the rhombohedral modification existing between modifications I and II in potassium nitrate is not detected in the studied sample. Partial replacement of K+ ions with Rb+ ions increases the equilibrium temperature between modifica-tions II and I by about 55 K.

Summary: The dielectric properties and power dissipation of PtSi/n-Si Schottky diodes of small area (8x10-6 cm2) were studied when the bias voltage varied in the range -2V ÷ 4V at room temperature. The amplitude of the alternating signal (Vac) varied from 5 mV to 1x103 mV. Studies based on impedance measurements revealed the dependence of dielectric parameters (ε', ε″), ac-conductivity (σac) and power dissipation (P) only at Vac = 200 mV. The obtained result is explained by the inhomogeneity of polarization and surface states.

Summary: In this paper, the magnetization of diluted magnetic semiconductor superlattices with a magnetic impurity of manganese is studied. It was found that the magnetization of a quasi-two-dimensional electron gas, depending on the degree of filling of the miniband superlattices, the molar concentration of the impurity, the exchange interaction constant and the spin splitting factor, changes sign and in a strictly two-dimensional case becomes positive. In a magnetic field, magnetization oscillates, and in strong magnetic fields the oscillations weaken, and their amplitude and frequency decrease. The contribution of the impurity to the magnetization is calculated. In a relatively weak magnetic field the magnetization associated with the impurity increases linearly and at a certain condition to the depending on the magnitude of the exchange constant and the impurity concentration changes its sign.

Summary: In this work have been presented the result of investigation of K0,945Ag0,055NO3 and K0,945Cs0,055NO3 single crystals were grown from aqueous solution of KNO3, AgNO3 and CsNO3 using isothermal crystallization method. Then, structural and phase transformations in samples were studied by X-ray and optical microscopy methods. It has been determined that in K0,945Ag0,055NO3 monocrystal at T393K temperature, in K0,945Cs0,055NO3 monokrystal at T455K temperature the rhombic (II)  hexagonal (III) transformation occurs with the formation and growth of the III - modification crystal embryo within II – modification. The results obtained from the kinetic studies were determined that the temperature dependence of the conversion rate of II  III in K0,945Ag0,055NO3 and K0,945Cs0,055NO3 single crystals can be expressed by an empirical formula of υ=(aΔT+bΔT^2+cΔT^3)⋅10^(-2) cm/sec. ΔT=T_t-T_0 is temperature delay, T_t- is transformation temperature and is equilibrium temperature between interconverting modification crystals. Based on the results of velocity measurements, the activation energy of IIIII polymorphic transformations were calculated.

Summary: The article presents mathematical modeling and experimental study of microwave waveguide taking into account boundary value problems on the geometric middle of the domain. For the first time, general classes of local and nonlocal boundary value problems on the geometric middle of the domain for three-dimensional Bianchi-type equations for the electromagnetic field of microwave rectangular waveguide are investigated. New mathematical models of the electromagnetic field of microwave rectangular waveguide operating in the frequency range of 4,9-7,05 GHz are developed taking into account the nonlinearity of the medium, wave types and effective algorithms for solving the models are proposed, which made it possible to improve the electrical, magnetic, structural and operational parameters and characteristics of microwave rectangular waveguide. For E-type and H-type waves, 3D models of the distribution of electromagnetic field strengths in elementary regions of rectangular waveguide are developed. Experimental devices and functional circuits for measuring the parameters of the microwave path, including the electric and magnetic fields of a rectangular waveguide in a nonlinear state of the medium, were developed, and the parameters of the microwave rectangular waveguide were experimentally determined. Comparison of theoretical and experimental results of the electric and magnetic field strengths showed that the relative error for these parameters is 4%. This proved the adequacy of the theoretical and experimental results obtained. The proposed work differs from the existing [1-5] works in that, in this work, for the first time, the factor that the studied microwave waveguide is filled with nonlinear media is taken into account.

Summary: In an era marked by growing ecological challenges, geopolitical tensions, and widening socioeconomic inequalities, the quest for sustainable energy solutions emerges as a pivotal imperative for building resilience and promoting a fair and equitable future [1–3]. Grounded in the recognition that energy is fundamental to nearly every facet of human well-being and environmental sustainability, our shared mission is to explore the complex interplay of factors shaping energy resilience, vulnerability and transition pathways.

Summary: Nowadays, beams, boards and coatings with new complex properties are widely used in many branches of mechanical engineering and construction. The calculation and analysis of the amplitude characteristics of stability, strength and frequency of a structural element with these properties lead both to significant difficulties in mathematical terms and to the analysis of the results obtained, if ignored, serious errors may be made. Taking these into account, it becomes necessary to build mathematical models characterizing the real properties of the material when using a structural element made of new materials and establishing effective physical connections. There are materials in which the tensile strain diagrams characterizing their properties are diverse in tension-compression and torsion. Such materials include ceramics, some types of copper and cast iron, polymers, and composite materials. The mechanical and physical properties of these materials become strictly dependent on hydrostatic pressure. For materials with the above-mentioned specific property, classical elasticity and elastoplasticity cannot be considered under the conditions accepted by the theory of plasticity. In this paper, a problem of planar stability of an elastic, plastic plane differently resisting to tension and compression in pure bending is solved. It is assumed that the cross-section of the beam has one symmetry axis, under the action of concentrated moments applied at the ends of the bar is subjected to pure bending, and bending happens in the symmetry plane of the beam. Using the state of a neutral axis, absence of longitudinal force, continuity conditions for tension and compression, we determine the boundary of elastic and plastic domains. The equations of the loss of planar stability obtained for the classic case are reduced to the loss of planar stability for various modulus ideal elastic and plastic beams. The expressions of hardness for different modulus materials are obtained and are associated with critical moment and critical length. Expressions for calculating critical parameters for an ideally elastic, plastic beam with a rectangular cross section are obtained.