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Introduction. In response to the COVID-19 pandemic in the Russian Federation, comprehensive response measures were taken. One of these measures was the development of a viral genome aggregation platform (VGARus) to monitor virus variability. The aim of this paper is to describe the role of the VGARus platform in tracking genetic variation in SARS-CoV-2. Materials and methods. VGARus utilizes sequencing data and bioinformatics tools to monitor genetic variations in SARS-CoV-2. The viral genomes were aligned using NextClade, which also translated them into amino acids and identified mutations. The viral variability over time was analyzed by counting the number of amino acid changes compared to the reference sequence. Results. The analysis of data within VGARus enabled the identification of new virus variants, contributing to improved diagnostic tests and vaccine development. The platform allowed for the prediction of epidemiologic trends, facilitating a rapid response to changes in the epidemiologic situation. For example, using VGARus, an increase in COVID-19 incidence was accurately predicted in the summer of 2022 and early 2023, which were associated with the emergence of Omicron subvariants BA.5 and XBB. Data from the platform helps validate the effectiveness of primers and DNA probes to ensure high diagnostic accuracy and reduce the risk of false negatives. Conclusion. VGARus demonstrates the growing role of genomic surveillance in combating COVID-19 and improving preparedness for future infectious disease outbreaks. The platform is a powerful tool for generating evidence-based solutions to combat a pandemic and mitigate its health, economic and societal impacts. It provides the ability to promptly obtain information on the epidemiologic situation in a particular region of the Russian Federation, use genomic data for phylogenetic analysis, compare the mutational spectrum of SARS-CoV-2 sequences with foreign samples. VGARus data allow for both retrospective analysis and predictive hypotheses. For example, we can clearly see the dynamics of the change of different virus variants: sequences belonging to the Alpha, Beta, Delta, Omicron lineages and many less common ones, clearly form the upsurges of morbidity, the interaction of which is reflected in the epidemiological picture. It is also currently being expanded to monitor other pathogens, increasing its public health relevance.

Abstract Atomically thin semiconductor heterostructures provide a two-dimensional (2D) device platform for creating high densities of cold, controllable excitons. Interlayer excitons (IEs), bound electrons and holes localized to separate 2D quantum well layers, have permanent out-of-plane dipole moments and long lifetimes, allowing their spatial distribution to be tuned on demand. Here, we employ electrostatic gates to trap IEs and control their density. By electrically modulating the IE Stark shift, electron-hole pair concentrations above 2 × 1012 cm−2 can be achieved. At this high IE density, we observe an exponentially increasing linewidth broadening indicative of an IE ionization transition, independent of the trap depth. This runaway threshold remains constant at low temperatures, but increases above 20 K, consistent with the quantum dissociation of a degenerate IE gas. Our demonstration of the IE ionization in a tunable electrostatic trap represents an important step towards the realization of dipolar exciton condensates in solid-state optoelectronic devices.

The relevance of this research is necessitated by the need to advance geochemical prospecting methods for raw hydrocarbon deposits. The study aimed to design new migration models by the interpretation of surface geochemical survey data. In particular, the relationship behavior needs to be identified between the hydrocarbon migration intensity and the presence of oil-bearing reservoirs within the section. To reveal quantitative relationships between the oil show and the oil-bearing capacity of the section, a substantial body of geochemical data across different fields in West Siberia was processed herein. Field-type and in-office operations were being performed by the snow survey procedure. The СН4–С6Н14 saturated hydrocarbons were employed as the major measured parameter. No direct quantitative connection was found between the intensity of surface hydrocarbon anomalies and the section productivity. Nonetheless, the two basic factors were found to affect the structure of the surface geochemical field: first, oil-bearing reservoirs present in the section and, second, fluid-resistant properties of the above-productive strata. Despite a direct quantitative relationship between the oil-bearing capacity of the section and the intensity of surface hydrocarbon anomalies being absent, the large sample made it possible to determine quantitative measures of the surface geochemical field that credibly characterize territories whose sections hold oil-bearing horizons.

The present study deals with algorithms for the acquisition of a well-core digital model that is used in the Digital Well-Core technology or “Digital Petrophysics.” The study involved the initial implementation stage of this technology: identification of geometric dimensions of a sample and spatial scanning resolution, as well as of scanning and reconstruction settings to examine a well core in a SkyScan 1172 X-ray micro-CT system. Well-core samples 30 mm wide (7 µm/pixel resolution), 10 mm wide (4 µm/pixel resolution) and 5 mm wide (1.5 µm/pixel resolution) were examined by X-ray micro-computed tomography. The porosity coefficient of all samples was measured by the water-saturation and weighing method. The digital models were used to estimate the porosity coefficient compared to the standard method. The results demonstrated that the best convergence of micro-CT and standard method data was achieved with 5-mm samples at a 1.5 µm/pixel scan resolution. A study on digital model optimization through noise reduction in the NRecon standard software was also conducted and discovered that the best convergence of porosity coefficients was attained when smoothing was set at 8. The scanning and reconstruction settings proposed for well-core samples can be used to implement the Digital Well-Core technology.

Relevance. A submersible electric motor is the most vulnerable component of an electric centrifugal pumping unit used in in-situ leaching uranium mining. The accuracy of calculating the need for new electric motors directly affects the profitability of the uranium production. Aim. Development of a probabilistic reliability model for a submersible electric motor that provides the calculation of its failure probability for the upcoming period of time and allows estimating with sufficient accuracy the number of motors required to replace the failed ones. Methods. Statistical methods, survival analysis, statistical hypothesis testing. Results and conclusions. The authors conducted a study of three probabilistic reliability models for electric motors of submersible well pumping units used in in-situ leaching uranium mining. As a result of the study, the maximum likelihood estimates of model parameters were determined for each model; the adequacy of the models under study was checked based on nonparametric goodness-of-fit tests. Despite the fact that the test results did not allow excluding any of the considered models, a model based on a mixture of two Weibull distributions was selected as a probabilistic reliability model demonstrating higher consistency with real data, compared to the other models. At the same time, the analysis of the components of the mixture distribution indicated the presence of a group of electric motors with an uncharacteristically low time-to-failure value compared to the average value calculated for the entire set of equipment under study, and made it possible to estimate the share of such motors, which amounted to 8% of the total population. Possible reasons explaining such heterogeneity of data, according to the authors, are hidden manufacturing defects or more severe operating conditions in which some submersible electric motors operate.

The research has been carried out in European larch forest plantations (Larix decidua Mill.) with the recording of changes in their silvicultural effect and the properties of sodpodzolic soil under the canopy of plantations over a period of more than 40 years. The aim of this work is to determine the nature of changes in the morphological and physicochemical properties of soils under the canopy of European larch forest plantations over a long period (45 years) in the conditions of the north-eastern Moscow Region. The research has covered 2 sample plots located in the B2 type of site conditions (simple fresh subor), which corresponds to fresh blueberry pine forests. The first sample plot (permanent sample plot 46) is located in an artificial plantation created in 1871 by planting. As for the second one (permanent sample plot B-2), it is located in forest plantations created in 1870 by sowing. Throughout the entire period of the research, the forest plantations have been growing according to the Ia quality class and have significantly increased the stock of stem wood. In forest plantations of the sample plot 46, the stock increased by 470 m3/ha (the current increase over 42 years of observation has equaled to 11.2 m3/ha per year), and in forest plantations of the sample plot B-2 – by 417 m3/ha (the current increase over 41 years of observations has equaled to 10.2 m3/ha per year). This indicates that there is currently no decay in the cultivated stands: they function successfully up to a century and a half old. Over 45 years, there have been changes in the morphological and physicochemical properties of the soil. A decrease in the content of the clay fraction has been established, especially in the upper part of the soil profile. The actual, exchange and hydrolytic acidity of the soil have increased as indicators of the ongoing process of podzolization. At the same time, the thicknesses of the forest floor and the humus content in the humus-eluvial layer have risen. The absorption capacity, the content of the exchange bases and the degree of saturation with the bases have increased, especially in the upper horizons of the soil, and the hydrolytic acidity has risen. In general, over a 45-year period, there has been no significant deterioration in the properties of sod-podzolic soils under the canopy of European larch forest plantations, and there are even trends of improvement in some indicators.

Introduction. Hepatitis B virus (HBV) remains a pressing global public health concern. The clinical course of the disease, particularly its tendency towards chronicity and response to therapy, is significantly influenced by the HBV genotype and specific mutations. There is an imperative need for a straightforward, highly sensitive, and dependable method for whole genome sequencing of HBV. Objective. Development and testing of an amplification panel for HBV whole-genome sequencing. Materials and methods. We introduce an NGS amplification panel designed for genome sequencing of HBV on the Illumina platform. A panel consisting of 54 primers, divided into 2 pools and amplifying overlapping regions of the HBV genome up to 300 bp in length, was tested on 246 HBV DNA samples. Results. The studied samples represented a genotypic diversity of the virus, with a pronounced predominance of the genotype specific to the Moscow region: 216, 27, 2, and 1 sample were identified as genotype D, A, B, and E, respectively. Five samples contained at least one mutation associated with antiviral therapy resistance, and twenty-three samples contained at least one mutation associated with vaccine escape described in the literature. Conclusion. The present paper describes the stages of whole-genome sequencing of HBV, provides a laboratory protocol, nucleotide sequences of the primers and an approach to the data analysis. Using a list of clinical samples as example, the reliability of the panel is shown. The HBV panel holds immense potential for utilization in scientific research, epidemiological monitoring, and advancement of personalized medicine approaches.

3D effects cause substantial underestimation of cloud optical thickness (COT) in airborne and satellite retrievals based on 1D radiative transfer computations (such as in the case of widely used bispectral technique). For a single-layer isolated cloud we propose a simple linear correction of the retrieved COT with the renormalization factor dependent on the cloud’s aspect ratio (the ratio between vertical and horizontal dimensions of the cloud). This is an empirical assumption which we successfully test using synthetic 3D RT data. We introduce a heuristic “block model” of 3D radiative effects and show that the functional form of the renormalization factor is consistent with the process of radiation escape from cloud sides in an essentially 3D geometry. We also extend the block model to the case of single-layer broken cloud field with radiative interaction between the neighboring clouds. In this case the renormalization factor depends also on the distance between clouds.

Abstract The exploration of topologically-ordered states of matter is a long-standing goal at the interface of several subfields of the physical sciences. Such states feature intriguing physical properties such as long-range entanglement, emergent gauge fields and non-local correlations, and can aid in realization of scalable fault-tolerant quantum computation. However, these same features also make creation, detection, and characterization of topologically-ordered states particularly challenging. Motivated by recent experimental demonstrations, we introduce a paradigm for quantifying topological states—locally error-corrected decoration (LED)—by combining methods of error correction with ideas of renormalization-group flow. Our approach allows for efficient and robust identification of topological order, and is applicable in the presence of incoherent noise sources, making it particularly suitable for realistic experiments. We demonstrate the power of LED using numerical simulations of the toric code under a variety of perturbations. We subsequently apply it to an experimental realization, providing new insights into a quantum spin liquid created on a Rydberg-atom simulator. Finally, we extend LED to generic topological phases, including those with non-abelian order.

Silicon-carbon films are of great interest as diamond-like materials combining unique properties, e.g. high hardness, adhesion to a wide range of materials, abrasion resistance, chemical resistance, low friction coefficient and biocompatibility. The presence of silicon in the films significantly reduces their inner mechanical stress as compared to diamond films. Currently, the films are used in industry, primarily, as solid lubricants and protective coatings. There are a large number of silicon-carbon film synthesis methods the most widely used of which are various options of chemical vapor deposition. A new silicon-carbon film synthesis technique has been suggested and tested. The technique is based on the use of high-frequency induction for obtaining plasma of silicon and carbon vapors supplied to the reaction chamber from an external source. Impurity-free silicon-carbon films containing 63–65 % carbon atoms with sp3 orbital hybridization have been synthesized on Sitall substrates. The composition, surface roughness and friction coefficient of the impurity-free silicon-carbon films synthesized using the suggested technology have been studied. The possibility of implementing resistive switching in thin silicon-carbon films in cross-bar structures with metallic electrodes has been analyzed.

Based on the completely integrable Calogero dynamical system, which describes the one-dimensional many-body problem, a tool for testing difference schemes has been developed and implemented in the original fdm package integrated into the Sage computer algebra system. This work shows how the developed tools can be used to examine the behavior of numerical solutions near the collision point and how to study the conservatism of the difference scheme. When detecting singularities using Alshina’s method, a difficulty was discovered associated with false order fluctuations. One of the main advantages of this set of tests is the purely algebraic nature of the solutions and integrals of motion.

Charged domain walls (CDWs) in ferroelectric materials raise both fundamental and practical interest due to their electrophysical properties differing from bulk ones. On a microstructure level, CDWs in ferroelectrics are 2D defects separating regions with different spontaneous polarization vector directions. Screening of electric field of the CDW's bound ionic charges by mobile carriers leads to the formation of elongated narrow channels with an elevated conductivity in initially dielectric materials. Controlling the position and inclination angle of CDW relative to the spontaneous polarization direction, one can change its conductivity over a wide range thus providing good opportunities for developing memory devices, including neuromorphic systems. This review describes the state of art in the formation and application of CDWs in single crystal uniaxial ferroelectric lithium niobate (LiNbO3, LN), as resistive and memristive switching devices. The main CDWs formation methods in single crystal and thin-film LN have been described, and modern data have been presented on the electrophysical properties and electrical conductivity control methods of CDWs. Prospects of CDWs application in resistive and memristive switching memory devices have been discussed.

This work is devoted to the implementation and testing of the Adams method for solving ordinary differential equations in the Sage computer algebra system. The Sage computer algebra system has, to some extent, trivial means for numerical integration of ordinary differential equations, but at the same time, it is worth noting that this environment is convenient and practical for conducting computer experiments related to symbolic numerical calculations in it. The article presents the FDM package developed on the basis of the RUDN, which contains the developments of recent years, performed by M. D. Malykh and his students, for numerical integration of differential equations. In this package, attention is paid to the visualization of the calculation results, including the construction of various kinds of auxiliary diagrams, such as Richardson diagrams, as well as graphs of dependence, for example, the value of a function or step from a moment in time. The implementation of the Adams method will be considered from this package. In this article, this implementation of the Adams method will be tested on various examples of input data, and the method will also be compared with the Jacobi system. Exact and approximate values will be found and compared, and an estimate for the error will be obtained.

Background and Objectives: This study analyzes the issues of position dislocation of the head of the superior poles and lateral points of the outer edge of the middle divisions of each of the thyroid lobes (TL) changes. The purpose was to provide an intravital position study of the clinical anatomy of the middle and superior poles of the thyroid gland (TG). Materials and Methods: We used data on anthropometry obtained during the study and data from MRI of the neck organs and anatomical formations of 100 healthy individuals, comprising 55 (55%) female and 45 (45%) male participants. To evaluate the data obtained in the examined group, the minimum probability value was 0.95 (95% confidence interval or p < 0.05). Results: Maximum flexion of the neck the distance from the center of the jugular notch to the lateral points of the outer edge of the middle parts of the TL decreases in all groups of but mostly in male ectomorphs; the same distance to the superior poles of the TG changes most in ectomorphic males on the right by 38.9% (p value < 0.001) and mesomorphic females on the left by 37.8% (p value < 0.001); in rotation to the left, the maximum was found in male ectomorphs, which decreased by 9.5% on the left (p value < 0.001) and by 7.3% on the right (p value < 0.001). Conclusions: this study provided new information about the intravital anatomy of the TG position, of the superior poles, and the lateral points of the middle part of its lobes.

Introduction. The design of studies aimed at finding the association between the genetic factor and the studied feature (disease) involves a comparison of the ratio of genotypes or allelic proportions in the study group with those in the control group. At the stage of determining the ratio of genotypes of the studied polymorphisms in the reference group, researchers meet a number of problems, which are the subject of the present work. Aim of the work is to provide scientific rationale for the feasibility of creating a national information system comprising genetic data of the relatively healthy population of Russia, incorporating its ethnic diversity. Materials and methods. The study group, total 1020 people, was genotyped for a number of single nucleotide polymorphisms of human genes. A comparative characteristic of the frequency distribution of the studied polymorphisms with those presented in international databases as reference data was carried out using χ2 index. Results. The frequency of SNP rs4986790 of the TLR4 gene significantly differs from the EUR population (p = 0.032) and the CEU subpopulation (p = 0.047). The allele frequencies of the rs1800795 (IL6) and rs1800896 (IL10) polymorphisms in the study population differ from the CEU subgroup (p = 0.030 and 0.012, respectively). The frequency of SNP rs2295119 (HLA-DPA2) in the study group is significantly different from the EUR population (p = 0.034). Conclusion. The analysis carried out in this work confirms the need to create a domestic information system containing data on the occurrence of SNP alleles and genotypes for a conditionally healthy population and in subgroups with various pathological conditions.

Magnetoelectric (ME) composites have a wide range of possible applications, especially as room-temperature sensors of weak magnetic fields in magnetocardiography and magnetoencephalography medical diagnostic equipment. In most works on ME composites, structures are tested in uniform magnetic fields; however, for practical application, detailed knowledge of their behaviour in inhomogeneous magnetic fields (IMFs) is necessary. In this work, we measured IMFs with radial symmetry produced by alternate currents (AC) passing through an individual thin wire upon different placements of an ME sensor. An ME self-biased b-LN/Ni/Metglas structure with a sensitivity to the magnetic field of 120 V/T was created for IMF detection. The necessity of an external biasing magnetic field was avoided by the inclusion of a nickel layer having remanent magnetization. The ME composite shows a non-zero ME coefficient of 0.24 V/(cm · Oe) in the absence of an external DC magnetic field. It is shown that the output voltage amplitude from the ME composite, which is located in an AC IMF, is dependent on the relative position of the investigated sample and magnetic field lines. Maximum ME signal is obtained when the long side of the ME sample is perpendicular to the wire, and the symmetry plane which divides the long side into two similar pieces contains the wire axis. In the frequency range from 400 Hz to 1000 Hz in the absence of vibrational and other noises, the detection limit amounts to (2 ± 0.4) nT/Hz1/2.

Dynamical decoupling and Hamiltonian engineering are well-established techniques that have been used to control qubit systems. However, designing the corresponding methods for qudit systems has been challenging due to the lack of a Bloch sphere representation, more complex interactions, and additional control constraints. By identifying several general structures associated with such problems, we develop a formalism for the robust dynamical decoupling and Hamiltonian engineering of strongly interacting qudit systems. Our formalism significantly simplifies qudit pulse-sequence design while naturally incorporating robustness conditions necessary for experimental practicality. We experimentally demonstrate these techniques in a strongly interacting, disordered ensemble of spin-1 nitrogen-vacancy centers, achieving more than an order-of-magnitude improvement in coherence time over existing pulse sequences. We further describe how our techniques enable the engineering of exotic many-body phenomena such as quantum many-body scars, and open up new opportunities for quantum metrology with enhanced sensitivities. These results enable wide-reaching new applications for dynamical decoupling and Hamiltonian engineering in many-body physics and quantum metrology.

Classical optimization problems can be solved by adiabatically preparing the ground state of a quantum Hamiltonian that encodes the problem. The performance of this approach is determined by the smallest gap encountered during the evolution. Here, we consider the maximum independent set problem, which can be efficiently encoded in the Hamiltonian describing a Rydberg atom array. We present a general construction of instances of the problem for which the minimum gap decays superexponentially with system size, implying a superexponentially large time to solution via adiabatic evolution. The small gap arises from locally independent choices which cause the system to initially evolve and localize into a configuration far from the solution in terms of Hamming distance. We investigate remedies to this problem. Specifically, we show that quantum quenches in these models can exhibit signatures of quantum many-body scars, which in turn, can circumvent the superexponential gaps. By quenching from a suboptimal configuration, states with a larger ground-state overlap can be prepared, illustrating the utility of quantum quenches as an algorithmic tool.

Dynamically field-programmable qubit arrays (DPQA) have recently emerged as a promising platform for quantum information processing. In DPQA, atomic qubits are selectively loaded into arrays of optical traps that can be reconfigured during the computation itself. Leveraging qubit transport and parallel, entangling quantum operations, different pairs of qubits, even those initially far away, can be entangled at different stages of the quantum program execution. Such reconfigurability and non-local connectivity present new challenges for compilation, especially in the layout synthesis step which places and routes the qubits and schedules the gates. In this paper, we consider a DPQA architecture that contains multiple arrays and supports 2D array movements, representing cutting-edge experimental platforms. Within this architecture, we discretize the state space and formulate layout synthesis as a satisfiability modulo theories problem, which can be solved by existing solvers optimally in terms of circuit depth. For a set of benchmark circuits generated by random graphs with complex connectivities, our compiler OLSQ-DPQA reduces the number of two-qubit entangling gates on small problem instances by 1.7x compared to optimal compilation results on a fixed planar architecture. To further improve scalability and practicality of the method, we introduce a greedy heuristic inspired by the iterative peeling approach in classical integrated circuit routing. Using a hybrid approach that combined the greedy and optimal methods, we demonstrate that our DPQA-based compiled circuits feature reduced scaling overhead compared to a grid fixed architecture, resulting in 5.1X less two-qubit gates for 90 qubit quantum circuits. These methods enable programmable, complex quantum circuits with neutral atom quantum computers, as well as informing both future compilers and future hardware choices.

Link for citation: Butakov V.I., Slagoda E.A., Zavatsky M.D., Ivanov V.I. Gas composition and microorganisms of ground ice in Russian Arctic. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 9, рр. 63-75. In Rus. Relevance. The increase in the concentration of greenhouse gases in the atmosphere is a fundamental problem on a planetary scale. The source of greenhouse gases in the subsurface horizon of soil can be both deep deposits of hydrocarbons and organic matter processed by microorganisms during the thawing of the ice-rich soil. To determine the source of the gas it is necessary to examine both its quantity and composition and the microorganism content in the subsurface ice. Taking into account the dynamic development of the energy complex in the north of Western Siberia it is necessary to take into account the geotechnical risks associated with the release of greenhouse gases from frozen deposits. Purpose: to study the composition and identify the sources of greenhouse gases in the ice and the ice-rich soil on account of the ice formation conditions and the microorganism content. Objects: ice wedge, hydrogenic and segregational genesis of ice, ice-rich soil of northern Western Siberia and Central Yakutia, collected by expeditions Earth Cryosphere Institute, Tyumen scientific center SB RAS in 2011–2021. Methods of research and interpretation of chemical composition. The structure of frozen deposits has been investigated by cryolitological methods. The monoliths of the ice and the frozen deposits were stored at –18 °C. Gas was extracted from the monoliths with the determination of volume fraction by thermovacuum degassing method. The composition of gases is determined by gas chromatography. Normalization of the gas composition with solubility values in water was carried out. Volume fractions of gas in free and dissolved forms was calculated. The data processing were implemented by means of «Geochem Anomaly» program. Cultivated psychrophilic microorganisms were studied by seeding on nutrient media; the total number of microorganisms was determined by epifluorescent microscopy. Results. The contents of N2 (74,9–87,8 %), O2 (11,7–20,3 %), CO2 (0,01–3,28 %), CH4 (0,003–7, 35 %), H2 (0,001–0,035 %) and hydrocarbons with an atom content from 2 to 6 (2,0×10–5–2,8×10–3 %) are determined in ice and ice-rich soil. The value of N2 and O2 in the gas composition of ice is close to atmospheric air. The ice has wide variations in gas saturation (1,1–21,1 %), CH4 and CO2 content. The freezing of gas-saturated solution occurred for the ice formation, part of the air was in a free form (from 30 to 75 %). Calculated indexes CH4/(C2H6+C3H8) and C2H6/C2H4 indicate biogenic hydrocarbon genesis. The composition of gas bubbles is recalculated for the volume of the entire sample: CH4 content is insignificant in ice wedge, closed-cavity ice and icing (averages 51, 81 and 1 ppmV, respectively). The low amounts of CH4 could be produced by forming these types of ice from the sediments of the active layer, as the dependence of the gas composition on the peat element amount is established. CH4, CO2 and H2 contents increased in samples with peat elements. In interbedding ice the CH4 content is high (216 ppmV). CO2 (up to 3007 ppmV) was accumulated in the texturing ice, and hydrogenic wedge-shaped ice showed high levels of CH4 (up to 4032 ppmV) as the ice was frozen in an enclosed volume. The ice of peat mound has a maximum content of CH4 (15545 ppmV) and high CO2 (2466 ppmV); inclosing sediments flooded with marginal-marine waters are the source of high values of CH4 and CO2. The cultivated psychrophilic microorganisms were identified in the surface ice, and their maximum quantities were identified in segregated formations – up to 1680 KOU/ml, in textural ice – up to 1032 KOU/ml. High concentrations of greenhouse gases are found in frozen peat – CO2 (1075 ppmV), H2 (9 ppmV), CH4 (262 ppmV) and other hydrocarbons due to activity of microorganisms, which results in accumulation of these gases. High gas saturation and CH4 and CO2 levels indicate the formation of gaseous composition by both aerobic and anaerobic microorganisms.

The effect of annealing in a permanent magnetic field on the magnitude of magnetoelectric coefficient in three-layered gradient magnetoelectric LiNbO3/Ni/Metglas composites has been studied. A method of electrochemical nickel deposition on bidomain lithium niobate crystals has been demonstrated. We show that the optimum annealing temperature in a permanent magnetic field for the generation of the highest remanence in the Ni layer is 350 °C. The specimens annealed at this temperature exhibit the greatest shift of the magnetoelectric coefficient dependence on external magnetic field magnitude relative to the value Hdc = 0. The quasi-static magnetoelectric coefficient in the absence of an external magnetic field proves to be 1.2 V/(cm ∙ Oe). The highest magnetoelectric coefficient that has been achieved at a bending structure resonance frequency of 278 Hz proves to be 199.3 V/(cm ∙ Oe) without application of an external magnetic field. The experimental magnetoelectric coefficient figures for three-layered gradient LiNbO3/Ni/Metglas composites are not inferior to those for most magnetoelectric composite materials reported earlier.

The paper discusses the relationship between the modes traveling along the axis of the waveguide and the standing modes of a cylindrical resonator, and shows how this relationship can be explored using the Sage computer algebra system. In this paper, we study this connection and, on its basis, describe a new method for constructing the dispersion curve of a waveguide with an optically inhomogeneous filling. The aim of our work was to find out what computer algebra systems can give when calculating the points of the waveguide dispersion curve. Our method for constructing the dispersion curve of a waveguide with optically inhomogeneous filling differs from those proposed earlier in that it reduces this problem to calculating the eigenvalues of a self-adjoint matrix, i.e., a well-studied problem. The use of a selfadjoint matrix eliminates the occurrence of artifacts associated with the appearance of a small imaginary addition to the eigenvalues. We have composed a program in the Sage computer algebra system that implements this method for a rectangular waveguide with rectangular inserts and tested it on SLE modes. The obtained results showed that the program successfully copes with the calculation of the points of the dispersion curve corresponding to the hybrid modes of the waveguide, and the points found fit the analytical curve with graphical accuracy even when with a small number of basis elements taken into account.

AbstractThe present study aimed to identify the formation factors of the current hydrogeochemical character of the Middle-Jurassic aquifer groundwaters (beds YU 2–4) in the Lyaminsky petroleum district of West Siberia in Russia. We hypothesized that the scales of the impact of post-sedimentation processes at the current stage have largely predetermined the character of the Middle-Jurassic aquifer system. To check if the hypothesis is valid, two research problems have been addressed using the lithogenesis theory of the transformation of the groundwater composition during the geologic evolution: we have evaluated factors that governed the genetic type and composition of initial waters (lithologic, paleogeographic), and factors that control subsequent changes in the chemical composition of groundwaters (geotemperatures, neotectonics effect, etc.). To solve the first problem, the formation conditions of groundwaters under study in the continental setting were investigated. To settle the second problem, we obtained the coefficients of correlation between the Middle-Jurassic aquifer groundwater salinity and the current temperature and paleotemperature of the Tyumenian suite, and between the porosity coefficient and the basement depth. We have concluded that the current hydrogeochemical character of the Middle-Jurassic aquifer system is the resultant of the consecutive effects of the whole set of factors.

The use of multilevel quantum information carriers, also known as qudits, has attracted significant interest as a way of further scaling quantum computing devices. However, such multilevel systems usually express shorter coherence time than their two-level counterparts, which limits their computational potential. We thus propose and experimentally demonstrate two approaches for realizing the continuous dynamical decoupling of magnetic-sensitive states with mF = ±1 for qudits encoded in optical transition of trapped 171Yb+ ions. We improve the coherence time of qudit levels by an order of magnitude (more than 9 ms) without any magnetic shielding, revealing the potential advantage of the symmetry of the 171Yb+ ion energy structure for counteracting magnetic field noise. Our results are a step toward realizing qudit-based algorithms using trapped ions.

The indigenous populations of the Arctic regions of Russia experience the lowest coverage of health-related services. We assessed the prevalence of hepatitis A, B, C, D and E viruses (HAV, HBV, HCV, HDV and HEV) among 367 healthy adult Native people of the Arctic zone of Yakutia. The HAV seroprevalence was above and increased with age. The anti-HEV IgM and IgG antibody detection rates were 4.1% and 2.5%, respectively. The average HBsAg detection rate was 4.6%, with no positive cases identified in participants aged under 30 years, confirming the effectiveness of the newborn vaccination program that began in 1998. Anti-HDV antibodies were detected in 29.4% of HBsAg-positive cases. The anti-HCV and HCV RNA detection rates peaked in the age cohort of 50–59 years (10.8% and 3.9%). No statistically significant gender differences in the prevalence of different viral hepatitis were observed. The time-scaled phylogenetic analysis demonstrated that all HBV genotype A and D strains isolated in this study were autochthonous and had an estimated most common recent ancestor (MCRA) age of around the 11th to 14th century. Unlike HBV, the HCV strains of subtypes 1b, 2a and 2k/1b were introduced from other regions of Russia in the 1980s and 1990s. The HCV 1b sequence analysis revealed a series of transmission events. In conclusion, these data emphasize the urgent need for expanded viral hepatitis screening and care programs in the indigenous populations of the Arctic zone of Yakutia.

Demonstrating quantum advantage requires experimental implementation of a computational task that is hard to achieve using state-of-the-art classical systems. One approach is to perform sampling from a probability distribution associated with a certain class of highly entangled many-body wave functions. It has been suggested that such a quantum advantage can be certified with the linear cross-entropy benchmark (XEB). We critically examine this notion. First, we consider a “benign” setting, where an honest implementation of a noisy quantum circuit is assumed, and characterize the conditions under which the XEB approximates the fidelity of quantum dynamics. Second, we assume an “adversarial” setting, where all possible classical algorithms are considered for comparisons, and show that achieving relatively high XEB values does not imply faithful simulation of quantum dynamics. Specifically, we present an efficient classical algorithm that achieves high XEB values, namely 5–12% of those obtained in the state-of-the-art experiments, within just a few seconds using a single GPU machine. This is made possible by identifying and exploiting several vulnerabilities of the XEB, which allows us to achieve high XEB values without simulating a full quantum circuit. Remarkably, our algorithm features better scaling with the system size than a noisy quantum device for commonly studied random circuit ensembles in various architecture. We quantitatively explain the success of our algorithm and the limitations of the XEB by using a theoretical framework, in which the dynamics of the average XEB and fidelity are mapped to classical statistical mechanics models. Using this framework, we illustrate the relation between the XEB and the fidelity for quantum circuits in various architectures, with different choices of gate sets, and in the presence of noise. Taken together, our results demonstrate that XEB’s utility as a proxy for fidelity hinges on several conditions, which should be independently checked in the benign setting, but cannot be assumed in the general adversarial setting. Therefore, the XEB on its own has a limited utility as a benchmark for quantum advantage. We briefly discuss potential ways to overcome these limitations.

Practical quantum networks require interfacing quantum memories with existing channels and systems that operate in the telecom band. Here we demonstrate low-noise, bidirectional quantum frequency conversion that enables a solid-state quantum memory to directly interface with telecom-band systems. In particular, we demonstrate conversion of visible-band single photons emitted from a silicon-vacancy (SiV) center in diamond to the telecom O band, maintaining low noise (g^{2}(0)

We propose for the first time a method for extracting the instantaneous phases of respiration from the signal of a photoplethysmogram (PPG). In addition to the instantaneous phases of respiration, this method allows for more accurately extracting the instantaneous frequencies of respiration from a PPG than other methods. The proposed method is based on a calculation of the element-wise product of the wavelet spectrum of a PPG and the sequence of intervals between the heartbeats extracted from a PPG, and a calculation of the skeleton of the resulting spectrum in the respiratory frequency range. It is shown that such an element-wise product makes it possible to extract the instantaneous phases and instantaneous frequencies of respiration more accurately than using the wavelet transform of a PPG signal or the sequence of the heartbeat intervals. The proposed method was verified by analyzing the signals from healthy subjects recorded during stress-inducing cognitive tasks. This method can be used in wearable devices for signal processing.

Andersen et al. have demonstrated a new type of beam steering device based on the excitonic response of an atomically thin semiconductor. Using electrostatic gates, the authors achieved tunable steering with switching times on the nanosecond scale.

The relevance of the topic is caused by the need to determine the nature of the elevated uranium content in sediments at the site of the two-hole in situ leaching experiment, to monitor the quality of groundwater, to identify its potential for self-restoration of natural equilibrium and conditions for self-purification of the ore-bearing horizon without the need for special reclamation. The purpose of the research is to determine the neutralizing properties of ore-hosting rocks in relation to the technogenic components entering the subsoil during in situ leaching; study of changes in the concentration of polluting components in groundwater and the mineral composition of ore-bearing rocks at the site of the two-hole in situ leaching experiment. Object is ore-bearing sediments and groundwater of the Taborinsky suite of Middle-Upper Jurassic age (J2-3tb), studied at the site of the two-hole in situ leaching experiment (check borehole 224) within the Dobrovolnoe deposit. Methods. Groundwater composition was studied directly at the drilling site of the check borehole; mineralogical and analytical studies were performed using traditional and precision methods in the laboratories of the All-Russian Scientific-Research Institute of Mineral Resources named after N.M. Fedorovsky, the studies were carried out using the JEOL JHA 8100 X-ray microanalyzer, equipped with an INCA energy dispersive prefix and a scanning electron microscope with the most representative sample in order to study the chemical composition, morphology and detailed pattern of the uranium mineralization distribution. Radioisotope studies were performed by gamma-spectrometric method using «ORTEC-65195-P/DSPecPlus» according to the methodology developed by All-Russian Scientific-Research Institute of Mineral Resources named after N.M. Fedorovsky. In order to study the effect of the vital activity of microorganisms on the physico-chemical properties of the medium, microbiological studies were carried out at the S.N. Vinogradsky Institute of Microbiology of the Russian Academy of Sciences. Results. Uranium concentrations remaining after the two-hole in situ leaching experiment were identified; uranium redeposition intervals were determined. It was found that 30 years after the experiment, groundwater at the Dobrovolnoe deposit was restored almost to original state. It is confirmed that uranium in situ leaching at the Dobrovolnoe deposit is environmentally sound, and the burial of man-made components introduced into the ore-bearing horizon occurs in the immediate vicinity of the mining site.

One of the possible versions of quantum mechanics, known as Kuryshkin-Wodkiewicz quantum mechanics, is considered. In this version, the quantum distribution function is positive, but, as a retribution for this, the von Neumann quantization rule is replaced by a more complicated rule, in which an observed value AA is associated with a pseudodifferential operator O^(A){\hat{O}(A)}. This version is an example of a dissipative quantum system and, therefore, it was expected that the eigenvalues of the Hamiltonian should have imaginary parts. However, the discrete spectrum of the Hamiltonian of a hydrogen-like atom in this theory turned out to be real-valued. In this paper, we propose the following explanation for this paradox. It is traditionally assumed that in some state {\psi} the quantity AA is equal to {\lambda} if {\psi} is an eigenfunction of the operator O^(A){\hat{O}(A)}. In this case, the variance O^((A-)2){\hat{O}((A-\lambda)2)\psi} is zero in the standard version of quantum mechanics, but nonzero in Kuryshkins mechanics. Therefore, it is possible to consider such a range of values and states corresponding to them for which the variance O^((A-)2){\hat{O}((A-\lambda)2)} is zero. The spectrum of the quadratic pencil O^(A2)-2O^(A)+2E^{\hat{O}(A2)-2\hat{O}(A)\lambda + \lambda 2 \hat{E}} is studied by the methods of perturbation theory under the assumption of small variance D^(A)=O^(A2)-O^(A)2{\hat{D}(A) = \hat{O}(A2) - \hat{O}(A) 2} of the observable AA. It is shown that in the neighborhood of the real eigenvalue {\lambda} of the operator O^(A){\hat{O}(A)}, there are two eigenvalues of the operator pencil, which differ in the first order of perturbation theory by i⟨D^⟩{\pm i \sqrt{\langle \hat{D} \rangle}}.

Introduction. The article provides a historical review of how notarial system of the Tyva Republic — an eastern region of Russia — was taking its shape. The research interest towards the territory is determined by specific development features characteristic of public and state institutions in Tuva. Goals. The article aims to identify facts of historical experience in functioning of notaries in the territory of the republic from 1914 to the 1940s. Materials and methods. The study primarily explores documents from the National Archive of the Tyva Republic, such as official papers of the Department of the Commissioner for Uryankhai Krai and the Resettlement Agency, local khoshuu and sum administrations, and the Notarial Chamber of the Tyva Republic. Comprehensive analysis of normative regulations for notarial system issued after 1946 makes it possible to assert its complete existence in the mid-to-late 1940s. Results. The Russian Protectorate of 1914–1917 did not introduce the Notarial Regulations (1866) in the Uryankhai region due to national and geopolitical characteristics of the territory. In fact, notarial functions were performed by representatives of local ethnic elites (noyons), senior electives of Russian settlements, officials of the Resettlement Agency and the Department of the Commissioner for Uryankhai Krai. At that time, the indigenous population and peasant settlers had no shared understanding of private property, which caused many disputes resolved by local Russian officials. So, the period of the Tuvan People’s Republic (1921 to 1944) witnessed no shaping of notarial system. In a figurative sense, ‘notarial affairs’ were entrusted to local khoshuu and sum administrations (like village Soviets, notarial tables in district or city executive committees). The revealed documents, including the ‘Book of Orders for Kyzyl Notarial Office of Tuvan Autonomous Oblast, 1950 to 1958’ make it possible to precisely identify the earliest working day of the First Notarial Office of Kyzyl — February 1, 1945. Analysis of normative regulations for notarial system in Tuva presumes that general features of its functioning were formed along with other regions of Soviet Russia.

Abstract Background Understanding the role of various factors in 3D genome organization is essential to determine their impact on shaping large-scale chromatin units such as euchromatin (A) and heterochromatin (B) compartments. At this level, chromatin compaction is extensively modulated when transcription and epigenetic profiles change upon cell differentiation and response to various external impacts. However, detailed analysis of chromatin contact patterns within and between compartments is complicated because of a lack of suitable computational methods. Results We developed a tool, Pentad, to perform calculation, visualisation and quantitative analysis of the average chromatin compartment from the Hi-C matrices in cis, trans, and specified genomic distances. As we demonstrated by applying Pentad to publicly available Hi-C datasets, it helps to reliably detect redistribution of contact frequency in the chromatin compartments and assess alterations in the compartment strength. Conclusions Pentad is a simple tool for the analysis of changes in chromatin compartmentalization in various biological conditions. Pentad is freely available at https://github.com/magnitov/pentad .

In this work, the effect of long-term room temperature exposure on the electrical conductivity of the charged domain wall (CDWs) in nonpolar x-cut congruent lithium niobate (LiNbO3, LN) crystals has been studied. Bidomain ferroelectric structures containing head-to-head charged domain boundaries have been produced by diffusion annealing in air near the Curie temperature and by infrared annealing. The crystals have been reduction annealed in a nitrogen atmosphere for the formation of color centers and growth of the electrical conductivity. The current measured during the recording of the I-V curves of the specimens using scanning probe microscope after room temperature exposure for 91 days has been found to decrease. The effect of storage conditions on the electrical conductivity of the CDWs has been studied. Degradation of the electrical conductivity does not originate from the effect of environment on the crystal surface. It has been hypothesized that the degradation is caused by distribution of charge carriers shielding the bound charge of the CDWs.

Over the past decades, the problem of bacterial resistance to most antibiotics has become a serious threat to patients’ survival. Nevertheless, antibiotics of a novel class have not been approved since the 1980s. The development of antibiotic potentiators is an appealing alternative to the challenging process of searching for new antimicrobials. Production of H2S—one of the leading defense mechanisms crucial for bacterial survival—can be influenced by the inhibition of relevant enzymes: bacterial cystathionine γ-lyase (bCSE), bacterial cystathionine β-synthase (bCBS), or 3-mercaptopyruvate sulfurtransferase (MST). The first one makes the main contribution to H2S generation. Herein, we present data on the synthesis, in silico analyses, and enzymatic and microbiological assays of novel bCSE inhibitors. Combined molecular docking and molecular dynamics analyses revealed a novel binding mode of these ligands to bCSE. Lead compound 2a manifested strong potentiating activity when applied in combination with some commonly used antibiotics against multidrug-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus. The compound was found to have favorable in vitro absorption, distribution, metabolism, excretion, and toxicity parameters. The high effectiveness and safety of compound 2a makes it a promising candidate for enhancing the activity of antibiotics against high-priority pathogens.

Mode decomposition is a powerful tool for analyzing the modal content of optical multimode radiation. There are several basic principles on which this tool can be implemented, including near-field intensity analysis, machine learning, and spatial correlation filtering (SCF). The latter is meant to be applied to a spatial light modulator and allows one to obtain information on the mode amplitudes and phases of temporally stable beams by only analyzing experimental data. As a matter of fact, techniques based on SCF have already been successfully used in several studies, e.g., for investigating the Kerr beam self-cleaning effect and determining the modal content of Raman fiber lasers. Still, such techniques have a major drawback, i.e., they require acquisition times as long as several minutes, thus being unfit for the investigation of fast mode distribution dynamics. In this paper, we numerically study three types of digital holograms, which permits us to determine, at the same time, the parameters of a set of modes of multimode beams. Because all modes are simultaneously characterized, the processing speed of these real-time mode decomposition methods in experimental realizations will be limited only by the acquisition rate of imaging devices, e.g., state-of-the-art CCD camera performance may provide decomposing rates above 1 kHz. Here, we compare the accuracy of conjugate symmetric extension (CSE), double-phase holograms (DPH), and phase correlation filtering (PCF) methods in retrieving the mode amplitudes of optical beams composed of either three, six, or ten modes. In order to provide a statistical analysis of the outcomes of these three methods, we propose a novel algorithm for the effective enumeration of mode parameters, which covers all possible beam modal compositions. Our results show that the best accuracy is achieved when the amplitude-phase mode distribution associated with multiple frequency PCF techniques is encoded by Jacobi–Anger expansion.

In this paper, we studied the operability of various components of vacuum electronic devices manufactured using the novel chemical metallization of photopolymer 3D-printed structures technology (CMPS), which is being applied at the Institute of Applied Physics, Russian Academy of Sciences (IAP RAS), for operation from microwave to sub-terahertz ranges. The key feature of this production method is the 3D printing (SLA/DLP, MJM technologies) of products and their further metallization. The paper presents the main stages of the process of chemical copper plating of polymer bases in various electrodynamic systems with complex shapes. A significant difference in the geometry and operating conditions of the created elements forms certain approaches to their production, as described in this work. Experimental studies of the implemented microwave components were carried out up to 700 GHz in the “cold” measurements; some electrodynamic structures were examined under conditions of sub-gigawatt peak power; and complex-shaped electrodes with cooling channels were tested under a continuous high thermal load. The conducted research has demonstrated the high potential of the developed methods of additive manufacturing of microwave device components and the prospects for their successful application in the described areas.

A novel concept of a frequency-tuned sub-terahertz gyrotron based on a combination of an irregular low-frequency resonator and an external reflector has been proposed recently. A simulation was carried out for a fundamental-cyclotron-harmonic gyrotron that demonstrates the possibility of achieving high (10–30%) efficiencies in a wide (~10%) frequency range. A possible solution to the problem of narrow-band frequency-tunable external reflectors in the form of so-called modified planar Bragg structures is discussed. The manufacturing of such structures on the basis of a novel additive technology based on photopolymer 3D printing, as well as the results of “cold” experiments of the manufactured samples, are described in the paper.

The classical problem of the interaction of charged particles is considered in the framework of the concept of short-range interaction. Difficulties in the mathematical description of short-range interaction are discussed, for which it is necessary to combine two models, a nonlinear dynamic system describing the motion of particles in a field, and a boundary value problem for a hyperbolic equation or Maxwells equations describing the field. Attention is paid to the averaging procedure, that is, the transition from the positions of particles and their velocities to the charge and current densities. The problem is shown to contain several parameters; when they tend to zero in a strictly defined order, the model turns into the classical many-body problem. According to the Galerkin method, the problem is reduced to a dynamic system in which the equations describing the dynamics of particles, are added to the equations describing the oscillations of a field in a box. This problem is a simplification, different from that leading to classical mechanics. It is proposed to be considered as the simplest mathematical model describing the many-body problem with short-range interaction. This model consists of the equations of motion for particles, supplemented with equations that describe the natural oscillations of the field in the box. The results of the first computer experiments with this short-range interaction model are presented. It is shown that this model is rich in conservation laws.

By the middle of 1930s, largely due to the efforts of Russian emigrant scholars, Prague became a major center of the studies in Slavic history, in particular in the history of Czech cultural ties with other major centers of Slavic culture in the East. Russian historian A. V. Florovsky in the mid – second half of the 1930s worked on a number of studies on the history of Slavic culture. To a large extent, his research efforts were aimed at reconstructing the biography of the Belarusian enlightener F. Skoryna. There are some important materials in the Archive of the Russian Academy of Sciences that allow reconstructing the course of A. V. Florovsky’s research on the history of cultural contacts of several centers of Slavic culture – Vilna, Prague, Moscow – letters to him from Belarusian Slavists A. I. Lutskevich, V. I. Samoilo, F. Ilyashevich and V. Tolochko. The corpus of these sources on the history of Belarusian Slavic studies was supplemented by attribution of a previously unknown letter by A. I. Lutskevich. The complex of these materials made it possible to clarify the date of compilation and identify the manuscript of one of the articles by A. V. Florovsky «Initial stages of the development of printing among the Eastern Slavs». Letters from Belarusian Slavists to A. V. Florovsky show the mechanism of work of historians in conditions of strict political separation of Europe, separation from libraries and archival collections, discussion of important scientific hypothesis. The end of these contacts was put by a sharp change in the political situation in Eastern Europe in 1939–1940.

A waveguide with a constant, simply connected section S is considered under the condition that the substance filling the waveguide is characterized by permittivity and permeability that vary smoothly over the section S, but are constant along the waveguide axis. Ideal conductivity conditions are assumed on the walls of the waveguide. On the basis of the previously found representation of the electromagnetic field in such a waveguide using 4 scalar functions, namely, two electric and two magnetic potentials, Maxwells equations are rewritten with respect to the potentials and longitudinal components of the field. It appears possible to exclude potentials from this system and arrive at a pair of integro-differential equations for longitudinal components alone that split into two uncoupled wave equations in the optically homogeneous case. In an optically inhomogeneous case, this approach reduces the problem of finding the normal modes of a waveguide to studying the spectrum of a quadratic self-adjoint operator pencil.

The preservation of quadratic integrals on approximate solutions of autonomous systems of ordinary differential equations x=f(x), found by the trapezoidal scheme, is investigated. For this purpose, a relation has been established between the trapezoidal scheme and the midpoint scheme, which preserves all quadratic integrals of motion by virtue of Coopers theorem. This relation allows considering the trapezoidal scheme as dual to the midpoint scheme and to find a dual analogue for Coopers theorem by analogy with the duality principle in projective geometry. It is proved that on the approximate solution found by the trapezoidal scheme, not the quadratic integral itself is preserved, but a more complicated expression, which turns into an integral in the limit as t0.Thus the concept of conjugate difference schemes is investigated in pure algebraic way. The results are illustrated by examples of linear and elliptic oscillators. In both cases, expressions preserved by the trapezoidal scheme are presented explicitly.

We consider an arbitrary monoid MM, on which an involutive division is introduced, and the set of all its finite subsets SetMM. Division is considered as a mapping d:SetMM{d:SetM \times M}, whose image d(U,m){d(U,m)} is the set of divisors of mm in UU. The properties of division and involutive division are defined axiomatically. Involutive division was introduced in accordance with the definition of involutive monomial division, introduced by V.P. Gerdt and Yu.A. Blinkov. New notation is proposed that provides brief but explicit allowance for the dependence of division on the SetMM element. The theory of involutive completion (closures) of sets is presented for arbitrary monoids, necessary and sufficient conditions for completeness (closedness) - for monoids generated by a finite set XX. The analogy between this theory and the theory of completely continuous operators is emphasized. In the last section, we discuss the possibility of solving the problem of replenishing a given set by successively expanding the original domain and its connection with the axioms used in the definition of division. All results are illustrated with examples of Thomas monomial division.

Abstract A new mechanism for controlling the microstructure of products in manufacturing processes based on selective laser melting is proposed. The mechanism relies on generation of high-intensity ultrasonic waves in the melt pool by complex intensity-modulated laser irradiation. The experimental study and numerical modeling suggest that this control mechanism is technically feasible and can be effectively integrated into the design of modern selective laser melting machines.

Lithium niobate is a ferroelectric material finding a wide range of applications in optical and acoustic engineering. Annealing of lithium niobate crystals in an oxygen-free environment leads to appearance of black coloration and concomitant increasing electrical conductivity due to chemical reduction. There are plenty of literary data on the electrophysical properties of reduced lithium niobate crystals though contact phenomena occurring during electrical conductivity measurement as well as issues of interaction between the electrode material and the test specimens are almost disregarded. The effect of chromium and indium tin oxide electrodes on the results of measurements of electrophysical parameters at room temperature for lithium niobate specimens reduced at 1100 °C has been investigated. It was found that significant nonlinearities in the VACs of the specimens at below 5 V distort the specific resistivity readings for lithium niobate. This requires measurements at higher voltages. Impedance spectroscopy studies have shown that the measurement results are largely affected by capacities including those probably induced near the contacts. It has been shown that the experimental results are described adequately well by a model implying the presence of near-contact capacities that are parallel to the specimen’s own capacity. Possible mechanism of the induction of these capacities has been described and a hypothesis has been proposed of the high density of electron states at the electrode/specimen interface that can trap carriers, the concentration of trapped carriers growing with an increase in annealing duration.

An abstract description of the RichardsonKalitkin method is given for obtaining a posteriori estimates for the proximity of the exact and found approximate solution of initial problems for ordinary differential equations (ODE). The problem Ρ{{\Rho}} is considered, the solution of which results in a real number uu. To solve this problem, a numerical method is used, that is, the set Hℝ{H\subset \mathbb{R}} and the mapping uh:Hℝ{u_h:H\to\mathbb{R}} are given, the values of which can be calculated constructively. It is assumed that 0 is a limit point of the set HH and uh{u_h} can be expanded in a convergent series in powers of h:uh=u+c1hk+...{h:u_h=u+c_1h^k+...}. In this very general situation, the RichardsonKalitkin method is formulated for obtaining estimates for uu and cc from two values of uh{u_h}. The question of using a larger number of uh{u_h} values to obtain such estimates is considered. Examples are given to illustrate the theory. It is shown that the RichardsonKalitkin approach can be successfully applied to problems that are solved not only by the finite difference method.

The article discusses some positive and negative aspects, as well as trends in the choice of topics for final qualifying works by future musicians-teachers. In particular, among the positive signs, there is a noticeable decrease in the number of formal diploma “materials as needed”, their focus on the specific place of work of the student is becoming more clearly marked, and a wide range of issues is being discussed. At the same time, the author points out that the level of presentation of the material and critical analysis of sources is not always acceptable, as well as the inability of the graduate to identify different points of view, to investigate their argumentation. The author considers one of the ways to increase the effectiveness of scientific management of diploma works to be an appeal to a synergetic approach. The conceptual and methodological principles of the synergetic paradigm, due to the ability of various systems to self-development through the use of their internal capabilities according to nonlinear laws, are expressed in the pedagogy of music education in the multivariance of methods (and/or the alternative of their choice), relevant in the professional development of a musician-teacher. In such an educational model, this means giving each student the right to individually move towards professional and creative development, stimulating independent choice and making responsible decisions. This approach makes it possible for the scientific supervisor to assess and predict the future development of each student, to diagnose methodological and other gaps in time, to abandon excessive regulation of the educational process in favor of a more free, individual, creative content, as well as to take into account the professional context as accurately as possible.