Overhead power line wires are affected by various external factors such as wind, ice deposits, variable temperature conditions, excessive humidity. This eventually leads to fatigue failure of the wire. It consists in the origin and slow growth of a fatigue crack. The final stage of destruction is the sudden movement of the crack at high speed. The paper proposes a model of slow crack growth, at the mouth of which there is a grain boundary. Under the influence of external stress, a section of the border is a source of vacancies. The resulting vacancy concentration gradient between the grain boundary and the free surface at the crack mouth leads to a diffusion flow of vacancies into the crack. From the solution of the diffusion problem, the magnitude of the flow and the rate of increase in the crack length are found.

Keywords: crack, grain boundary, vacancy diffusion, fatigue failure, air line, mechanical stress, vacancy flow

The effect of impurities on the conductivity of the allotropic modification of phosphorene (ε-P) was studied. The quantum chemical research package Quantum Espresso was used for calculations. The study was conducted on the basis of simulation modeling. Three-dimensional structures are modeled using Quantum Espresso. The work adapted the model for two-dimensional ε-phosphorene by choosing a unit cell vector so large that interaction between the layers was possible. It has been shown that S has the smallest changes. Significant changes in conductivity can be achieved by placing F in various configurations relative to the crystal lattice, which can be actively used to create differetnt types of detectors.

Keywords: phosphorene, allotrope, semiconductor, impurity, adsorption, conductivity, density functional theory, modeling, Quantum Espresso, crystal structure

In this paper, the possibility of applying graph neural networks (NN) to study the structure of copper centers of zeolites is considered. The dataset used for NN training was prepared using the FDMNES software based on the finite difference method and included more than 2100 Cu K-XANES spectra for Cu-MOR. The performed study demonstrated the capability of graph neural networks to reproduce the Cu K-XANES spectrum corresponding to a particular model of the copper center in the zeolite framework.

Keywords: zeolite, mordenite, atomic structure, XANES, machine learning, graph neural networks

The possibilities of a little-studied method for obtaining nanosized materials of electronic engineering with a given substructure, the zone sublimation epitaxy (ZSE) method, are discussed. In the work, it is combined with the method of gradient liquid phase epitaxy (GLE). A specific feature is mass transfer in a two-phase medium (a solid substrate and an inert gas phase acting as a transport medium) with preliminary deposition of a matrix layer formed from the melt. A feature of the sublimation process in the study was the crystallization of low-melting iron-silicon eutectic. A mathematical model of the process was proposed and compared with the experimental results. Island structures of the composition silicon (more than 90%), iron (up to 8%) and chromium (about 1.5%) have been obtained. Their parameters and size distribution were studied. A Solver-HV scanning probe microscope and a Quanta-200 scanning electron microscope were used. The study shows that the use of sublimation transfer transients makes it possible to reproducibly form doped silicon nanolayers and transform them into regular mesostructures.

Keywords: microsize growth cell method, zone sublimation epitaxy, gradient liquid phase epitaxy, island nanostructures

The doelectric and polarization studies of the system of solid solutions PbxSr1-xTiO3 with x = 0.005, 0.02, 0.04 in a broad frequency and temperature range are performed. The temperature of the ferroelectric phase transition in the solid solutions is determined. The temperature behaviour of the remanent polarization at the phase transition is established.

Keywords: quantum paraelectric, strontium titanate, dielectric permittivity, remanent poalrization, superparaelectric state, phase transition

Concentration changes in the frequencies of Raman scattering spectra in binary molten salt systems of alkali metals with a common cation containing halide, nitrate and perchlorate anions are shown. The frequency constancy is noted when the composition of molten salt systems changes.

Keywords: melts, nitrates, perchlorates, alkali metal halides, raman spectra, binary salt systems

The testing of technique for modeling the local atomic structure and X-ray absorption spectra for zinc ions in an aqueous solution in the presence of arachidic acid has been adjusted. Models of the local structure of zinc with different coordination geometries are considered: planar, pyramidal, tetrahedral, and octahedral. The cases of increasing distances between the zinc ion and water molecules in the plane and in the axial direction are simulated for octahedral coordination. It has been established that the most probable change in the local structure of the zinc environment in solution in the presence of arachidic acid is the removal of water molecules from zinc ions in the axial position and their further replacement with the formation of a bond with the carboxyl group of arachidic acid.

Keywords: arachidic acid, lipid layer, local atomic structure, X-ray absorption spectroscopy, total external reflection, zinc, biomembrane, finite difference method, monolayer