Volume 19, Nº 3 (2023)

The paper studies the possibility of assessing the behavior of lithospheric plates of non-classical shape, located on a multilayer base. The study is driven by the need to survey the dynamic properties of such lithospheric plates due to the discovery of the possibility of their resonances. Resonances can affect the seismic state of the territory of the lithospheric plate and provoke earthquakes. As a lithospheric plate, a wedge-shaped plate in the form of a quarter of a plane is being studied. The solution of the problem under consideration is based on the possibility of solving the contact problem in a wedge-shaped region in which a deformable stamp acts. Solutions to boundary value problems for complex rheology dies are then a combination of solutions to boundary value problems for simple rheology dies. In this article, a previously developed new mathematical tool based on the fractal properties of block elements is used to analyze the problem under consideration. Given the practice of applying this approach, it is possible to achieve certain results. In earlier works, to obtain all the parameters describing the behavior of lithospheric plates in a quadrant, it was necessary to study three equations. In this paper, we construct one equation of the second kind with a completely continuous operator, which makes it possible to cover all the necessary parameters. It allows this equation to be approximated by a finite system of algebraic equations and it is rather simple to obtain a dispersion equation. The issues of consideration of lithospheric plates of complex rheologies are discussed.

Using the example of GaInAsP and GaInAsSbBi solid solutions grown on GaP substrates with crystallographic orientation (111), the features of pulsed laser deposition of multicomponent solid solutions based on group III–V compounds are studied. The solid solutions were chosen based on the indicated difficulties in growing by the method of pulsed laser deposition due to the fact that they consist of two group III metals and three highly volatile group V metalloids. Due to the relevance of their practical use for growing optoelectronic heterostructures by X-ray energy-dispersive microanalysis, scanning electron microscopy, and Raman scattering, an analysis of the composition of solid solutions and their morphology was carried out. It has been experimentally shown that the combination of an increase in the laser fluence and the addition of surface-active elements such as Bi or Sb to the composition makes it possible to reduce the droplet density on the surface of the grown film by three orders of magnitude, and reduce their average size from 300 nm to 45 nm. It was determined by X-ray energy-dispersive microanalysis that the droplets consist of indium. The main causes of stoichiometry violation are In droplets and partial desorption of V group elements. It has been established that the source of In droplets is the formation of a liquid fraction of In on the target surface during sputtering with a fluence of 2.3 J/cm2 and high surface diffusion of In from the bulk of the layer to the surface. It has been found that the introduction of surface-active elements into the composition of the solid solution leads to the prevention of desorption of highly volatile elements of the V group, for example, arsenic. It is shown that by increasing the laser fluence and selecting the composition of the solid solution, it is possible to improve the morphology of thin films grown by pulsed laser deposition.

To date, the geochemical circulation of artificial radionuclides that got into the natural environment after the Chernobyl accident has been observed in the Azov Sea basin. One of the ways of their migration is the Don River flowing through the catchment area exposed to radioactive contamination. The presented research results allow us to study the patterns of accumulation of artificial radionuclides in certain areas of the Don Delta and identify the main factors controlling this process. New data on the distribution of bottom sediments and the specific activity of man-made and natural radionuclides in them on the northern fl ank of the Don delta are analyzed. It was found that the content of the potentially dangerous technogenic radioisotope 137Сs in the sediments of the surface layer of the bottom of the channel in this section of the delta is characterized by a spectrum of values from 1.3 to 43.5 Bq/kg and depends on the lithotype of the bottom soil. According to the results of radiometric measurements, the maxima of its specific activity were recorded in fine silty sediments, and the minima – in sediments, in which sand with inclusions of shell material prevails. In the distribution of technogenic 137Сs, as well as natural radionuclides 40K, 226Ra, 232Th, there is a tendency for concentrations to increase in the direction from the border of the seashore to the top of the delta, which is associated with the conditions of transportation and accumulation of sedimentary material. In general, according to the results of the conducted studies, it is concluded that the specific activity of 137Сs in the surface layer of bottom sediments in the studied area is characterized as low, not causing danger to the marine ecosystem. The obtained new data on the composition of bottom sediments and the content of man-made and natural radionuclides in them will be useful in analyzing the radioecological situation in the southern region of Russia.

The results of studies of the content and distribution of various forms of copper and zinc in the calcic chernozem in the ampelocenoses of the central irrigated natural-agricultural zone of the Rostov Region are presented. It has been established that the content of gross and mobile forms of copper and zinc in the soils of industrial fields corresponds to the background level and does not exceed the maximum allowable concentrations. According to the content of mobile forms of biomicroelements, the supply of southern chernozem with zinc is low (<2.0 mg/kg), with copper ‒ medium (0.21‒0.50 mg/kg). When calculating the coefficients of radial differentiation, a general pattern was revealed in the distribution of gross and mobile compounds of copper and zinc under ampelocenosis conditions, due to their gradual decrease down the soil profile and active accumulation in humus-accumulative horizons. The content of the gross form of copper (horizon Ap ‒ 62.69 mg/kg) decreases down the profile by 31.7% to 42.80 mg/kg in horizon C, gross zinc in horizon Ap (98.47 mg/kg) decreases by 20.6% to 78.18 mg/kg in horizon C. The content of mobile forms of trace elements is also characterized by their gradual decrease: the amount of copper in the Ap horizon is 0.29 mg/kg, decreasing by 34.5% down the profile to 0.19 mg/kg (C horizon), for zinc ‒ by 50% from Ap horizon (0.36 mg/kg) to C horizon (0.18 mg/kg). It was revealed that the low content of mobile compounds of biomicroelements in the southern chernozem is due to its physicochemical properties, including the content of carbonates. An inverse correlation was noted between the studied trace elements and CaO: for copper r = −0.85, for zinc r = −0.81.

The studies were carried out on the territory of growth of natural populations of Pinus brutia var. pityusa (Steven) Silba in the Crimean Mountains. The purpose of the research was to study the orographic characteristics of the landscape, to identify the features of their influence on the state of the prospects for the development of P. brutia var. pityusa plantations. When conducting observations, we used methods of space sounding and a system of computerized assessment of the exposure and slope of individual sections of the studied territories, and determined the integral indicators of these characteristics in gradations according to altitudinal zones. As a result of the research, it was found that the orographic factors in total have a noticeable effect on the formation of P. brutia var. pityusa forest stands in the Crimean Mountains, especially at the first stages of their development. It was revealed that in the coastal zone in the Ayazma natural boundary, the steepness of the slopes has the most significant limiting effect. In the central part of the P. brutia var.pityusa forests in the Ayazma natural boundary, after forest stands were damaged by crown fires, the high steepness of the slopes contributes to the active development of erosion and landslide processes, especially in the area of clear sanitary felling. It is shown that in the Batiliman natural boundary, with a slight decrease in the steepness of the slope, their exposure plays an important role. On the southern slopes, which occupy most of the area of the Batiliman natural boundary, the growth opportunities for young P. brutia var. pityusa plants are deteriorating, which has a negative impact on the processes of its natural renewal. It has been established that an increase in the diversity of orographic conditions in terms of slope exposure also increases the dispersion of microclimatic conditions in Karaul-Oba Mountain in comparison with the territories of the western part of the growth of P. brutia var.pityusa in the Crimean Mountains. It is shown that the landscape features of the Novy Svet natural boundary – a relatively small slope and southeastern exposure of the slopes, an increase in the stability of the microclimate in the amphitheater basin, where most of the P. brutia var. pityusa plantations are located, provide an improvement in growing conditions. The total effect of orographic factors determined the growth possibilities of P. brutia var.pityusa in the territory of the Novy Svet natural boundary, the extreme eastern part of its distribution in the Crimean Mountains.

Up-to-date magnetobiology data provide enough evidence that weak magnetic fields, whether of artificial nature or connected with the solar and geomagnetic activity, have a certain biological influence. Magnetoreception – a sense of magnetic fields – is considered to play an important role in the orientation and navigation of some land and marine animals. Many marine mammals, both cetaceans and pinnipeds, migrate over long distances. And when magnetoreception in cetaceans is widely discussed among scientists, there aren’t many works about the sense of magnetic field in pinnipeds. We built an experimental stand based on the Helmholtz coils system to study the magnetosensitivity of pinnipeds. We took three mature female grey seals Halichoerus grypus atlantica as study objects. Seals were trained to choose from two or three identical Helmholtz coils the one which was generating the magnetic field at the moment of observations using the “instrumental conditioned reflex” method and method of selecting an object according to given characteristics. In the course of the experiment, we have found that generated magnetic field of 8, 20 and 36 Hz frequency and 110‒130 μT induction is a detectable stimulus for grey seals at the presentation of which they were able to develop a conditioned refl ex. The average rate of correct choices was over 79% during all check tests. Based on the acquired data we can state that grey seals have the ability of magnetoreception.