The article provides an overview and analysis of seismicity within the boundaries of the Arctic region for 2020 based on a consolidated catalog of earthquakes compiled from catalogs of the N. Laverov Federal Center for Integrated Arctic Research of the Ural Branch of the Russian Academy of Sciences, the Kola and Ya kutsk branches of the Geophysical Survey of the Russia Academy of Sciences (GS RAS), using data from the Seismological Bulletin of the GS RAS and the International Seismological Center. A total of 475 earthquakes are included in the consolidated catalog for 2020. Most of the earthquakes that occurred in 2020, including all the strongest earthquakes, were located within the mid-ocean ridges of Mon, Knipovich. Gakkel and Spitsbergen Fault Zone. In the offshore territories, most of the earthquakes were confined to the Svalbard archipelago, in particular, to the seismically active zone in the Sturfjord strait. Within the shelf areas, seismicity is also characteristic of the Novaya Zemlya archipelago, "continent-ocean" transition zone of the Barents-Kara region, Bely (Kvitøya) and Bear (Bjørnøya) Islands. For 17 earthquakes, the focal mechanism parameters are presented according to the Global CMT catalog.

To optimize the processes of obtaining high-purity arsine and elemental arsenic by the electrochemical method, the dynamic viscosity is calculated and the kinematic viscosity is measured in solutions of arsenic acid formed by the electrolysis of a solution of hydrolytic sodium arsenite, the main product of the destruction of lewisite, in a temperature range of 20–80°C and a wide concentration range of 20–74 wt %.

In low disturbance environment, laminar-turbulent transition (LTT) is associated with excitation of unstable normal modes of small initial amplitudes (receptivity problem). These modes grow exponentially to a critical amplitude in accord with the linear stability theory (LST) and trigger the nonlinear breakdown. In the current study numerical simulation of laminar-turbulent transition (LTT) in the boundary layer on the upper surface of a flat plate in a supersonic free stream of Mach number M-infinity=3 and Reynolds number Re-infinity=2 x 10(7) is carried out. The flow is perturbed by fast or slow acoustic waves of low intensity, which excite unstable waves of the first mode. The latter have frequencies corresponding to the integral amplification N approximate to 9.16 typical for flight conditions. Two cases are considered: the angle of attack AoA=0 degrees at which acoustic waves pass through a weak shock induced by viscous-inviscid interaction; AoA=5 degrees at which acoustic waves pass through the expansion fan emanating from the plate leading edge. A holistic modeling of all stages of the transition from receptivity to the birth of turbulent spots is performed using direct numerical simulations. Linear stability theory is used to interpret the results. Feasibility of practical implementation of the amplitude method for predictions of the LTT onset in the considered and similar cases is discussed. It has been shown that to realize the amplitude method in the considered and similar cases, it is sufficient: to calculate the initial amplitudes of instability in a small vicinity of the leading edge and the propagation of instability from the leading edge to the station where the instability reaches the critical amplitude u ' max approximate to 4%. Analysis of known numerical and experimental data showed that this criterion weakly depends on the local Mach number in the range 0<M-e<7, and it is acceptable for practical predictions of the transition onset points.

The luminescence and scintillation properties of YAG:Ce crystals grown from the melts in vacuum has been analysed. We have investigated absorption spectra, X-ray excited luminescence (XRL), XRL decay kinetics and scintillation light yield in a wide range of activator concentrations (from 0.0036 at.% to 1.175 at.% substitution of Y in the c-positions of garnet structure). The effective quenching of the intrinsic luminescence of antisite and vacancy defects of the crystal in the UV region with increasing activator concentration has been determined. The optimal concentration of the activator has been determined in order to increase the XRL intensity and the light output of scintillations of Сe3+ ions, taking into account the technological peculiarities of growing optically perfect single crystals with high concentration of Сe3+ ions by using the method of horizontal directional crystallisation in vacuum. The relations between the XRL kinetics and the activator concentration have been investigated. It has showed the possibility to obtain crystals with photon yield up to 25,000 ph/MeV.

The main interaction reactions in the Al2O3−N2 system are determined for a temperature of 2400 K and pressure of 1 bar. It is found that, in the absence of direct interaction of nitrogen (molecular and atomic) with the melt, chemical reactions may occur between nitrogen and the products of Al2O3 melt dissociative evaporation. The reactions of nitrogen oxidation and the interaction reactions between nitrogen oxides and the melt, both direct and with participation of elementary oxygen or gaseous aluminum oxides, are determined. It is shown that the elementary nitrogen forms may interact with melt jointly with nitrogen oxides and (or) with all Al-containing components of the system. The concentrations of the gaseous materials that are in equilibrium with Al2O3 are calculated by the Monte Carlo method.

In this paper we overview methods and algorithms for detecting seismic and infrasonic events, recognizing their types and location of their sources. Algorithms and methods used in processing records of both individual seismic stations and seismic and infrasonic arrays and networks of stations are considered. Particular attention is paid to the application of the considered algorithms in current automated data processing systems of seismic and infrasound monitoring. The general problem of data processing of seismic and infrasonic monitoring is divided into five main subproblems: detecting useful signals on the record—seismic or infrasonic waves—determining their parameters, and identifying them (determining wave types); searching for data fragments containing records of seismic or infrasonic events that must be processed by the system; associating detected events according to previously defined parameters for a network of stations; locating the source (epicenter/hypocenter) of seismic or infrasonic events; and source type recognition. Each subproblem and existing method for its solution are considered separately. The issues of the sequence of solving the above problems and the possibility of combining them depending on the specific implementation of the processing system and the specific goals of data analysis are discussed. Here, we review more than 100 papers describing both current high-performance algorithms and classical, but still relevant methods for processing seismic and infrasonic data, including our previously proposed algorithms.

This paper provides information about the main parameters of spatial broadband seismic network in the Kola region (the northeastern part of the Fennoscandian Shield). Since 2021 the seismic network has been expanded by five seismic stations and currently consists of nine stations located on the territory of the Russian Federation. Configuration of the network allows to broaden the scope of research of the Kola region lithospheric structure significantly. The prospects of integrating the newly installed stations into the automated regional seismic monitoring network are considered. The analysis of seismic noise in the places of installation of new seismic stations was carried out. It was shown that the data provided by the new broadband stations increases the accuracy of seismic events location in the research area.

This review surveys patent information and fundamental literature sources on the technological foundations of producing high-purity arsenic and its compounds in the leading countries: Russia (USSR), USA, Japan, Germany, and China. The 1960–1979 literature sources on the following issues are summarized:—recovery of elemental arsenic from various raw materials;—production of high-purity (99.99999 wt

Yttrium‒aluminum garnet single crystals, including cerium-doped ones, have been grown from melt by Bagdasarov’s method. A comparative spectroscopy study of garnet single crystals and specially prepared ceramics of the same composition has been carried out. The comparative analysis suggests that an increase in the concentration of cerium ions in the garnet crystals improves the spectral-luminescence and scintillation characteristics of the latter and facilitates effective quenching of the substrate luminescence. Ways of optimizing the synthesis conditions to improve the efficiency of scintillators based on Y _1-x Ce x 3 Al 5 O 12 garnet crystal have been proposed.

The article provides an overview of software products developed at the Kola Branch of the Geophysical Survey of the Russian Academy of Sciences. These software products are aimed at automating the detection, location, and analysis of seismic and infrasonic events both locally (monitoring mines) and regionally (monitoring seismic and infrasonic activity in regions). A software package is also considered for searching for fragments of spent launch vehicles using signals from shock waves generated during their return to the dense layers of the atmosphere. The created software products are implemented in organizations both in the Russian Federation and abroad. Some of the programs are certified.

A new design of a galvanic sensor of pulsed X-ray radiation is proposed, which is a flat electric capacitor with a window in one metal lining and a solid dielectric made of the single crystal sapphire with a thickness of 200-300 µm inside. The influence of the surface roughness of the sapphire in the window area on the galvanic linear sensor of X-ray radiation has been established. Tests have shown that with ultra-smooth polishing of the sapphire plate working surface in the window area to a roughness of Rq≤ 0.2 nm, it is possible to provide the galvanic linear detection of X-rays with an energy in the range of 0.1-1 keV and a power density of 1-2 MW•cm-2 with a sensor response time of about 8 ns. Sensors of this type can be used in studies of inertial nuclear fusion processes

A new design of a galvanic sensor of pulsed X-ray radiation is proposed, which is a flat electric capacitor with a window in one metal lining and a solid dielectric made of a single-crystal sapphire with a thickness of 200-300 μm inside. The influence of the surface roughness of the sapphire in the window area on the galvanic linear sensor of X-ray radiation has been established. Tests have shown that, with ultra-smooth polishing of the sapphire plate working surface in the window area to a roughness of R q ≤ 0.2 nm, it is possible to provide the galvanic linear detection of X-rays with an energy in the range of 0.1-1 keV and power density of 1-2 MW· cm -2 with a sensor response time of about 8 ns. Sensors of this type can be used in studies of inertial nuclear fusion processes. Keywords: X-ray radiation, galvanic sensor, sapphire, dielectric, flat capacitor.

The phenomena occurring in dielectrics (Al2O3 and SiO2) in the field of high-power soft X-ray radiation are investigated. Experimental studies are carried out at the Angara-5-1 facility, which allows a pulsed radiation power density of the source up to 5 MW/cm2 at the location of the examined samples. It is revealed that charge carriers are generated in the surface layer of the irradiated dielectric, which causes current generation in a circuit including the dielectric. A necessary condition for current generation is the presence of “hot” electrons, which provide surface conductivity. A mathematical model is proposed to describe the process of current generation in dielectrics during exposure to high-power pulsed X-ray radiation. The model is based on the joint solution of the kinetic equations for X-ray photons, photoelectrons, conduction electrons and holes in the valence band and self-consistent Maxwell’s equations. In Maxwell’s equations, instead of the external current of secondary charge carriers, the radiation conduction current is used.

This paper describes a detailed study aimed at developing technological principles of the preparation of 99.99995

The frequency behavior of spectral contributions of initial, middle, and end segments of the power-law function to the spectral density of a stationary random process is considered. Their oscillating sign-alternating frequency character is shown. The rate of fall of absolute values of the abovementioned contributions approaches an inverse relationship with an increase in the frequency. Simple analytical approximation relationships describing the frequency behavior of all abovementioned spectral contributions are presented and analyzed. They are recommended for common practical use. The use of the formulas obtained for more complicated composite power functions is considered.

This paper describes a detailed study aimed at developing technological principles of the preparation of 99.99995%-pure Cd, Zn, and Te by crystallization purification methods. We have analyzed the thermophysical properties of Cd, Zn, Te, and structural materials of the equipment involved; substantiated the choice of graphite as a crucible material; and determined its engineering features. We have studied impurity distributions in Cd, Zn, and Te in crystallization processes and determined effective performance parameters of the materials refining process in horizontal directional solidification and zone melting steps. The results have allowed us to obtain 99.99995 to 99.99999%-pure Cd, Zn, and Te in terms of 30 major impurities, with a maximum product yield of up to 85%.

An approach to recognizing the types of seismic event sources is proposed, based on the combination of several heterogeneous parameters of event records and information about the territory where the seismic event occurred. The following recording parameters are used: the ratio of the amplitudes of body waves, the ratio of parts of the spectra at high and low frequencies, the magnitude, and the spectral constancy parameter. Territorial information includes data on the presence of waterbodies, glaciers, mines, and simplified information on natural seismic activity. Their joint use is done with a special type of Bayesian belief network. The decisions made by the network are probabilistic in nature; the probability is understood in the Bayesian sense, i.e., as the degree of confidence in the truth of the judgment, which consists in attributing an event to one of the types (mine explosion, other explosion on land, underwater explosion, earthquake, icequake). The approach is implemented as a software system, which is included in the program for the interactive analysis of seismic event records LOS.

Processes and devices for the isolation and deep purification of elemental arsenic and arsenic-containing substances in leading countries since 1981 to the present are described.

The fundamentals of the technology to extract elemental arsenic from various raw materials, taking environmentally friendly treatment processes into account, are outlined. The data obtained from 1981 to the present, as well as physicochemical and technological bases for the extraction of arsenic from sulfide ores, waste from metallurgical and semiconductor industries, and nontraditional secondary raw materials, are summarized. The current state of this field is analyzed.

Extrapure-grade (99.9985 wt % pure) SnCl2 has been prepared from commercially pure metallic tin and hydrogen chloride gas. Purifying the synthesized tin(II) chloride in a fractional distillation column under normal conditions, we obtained extrapure-grade SnCl2 containing under 1 ppm impurities. The samples thus prepared were characterized by inductively coupled plasma mass spectrometry, IR and Raman spectroscopies, and X-ray diffraction.