Yttrium-aluminum garnet crystals with a gradient distribution of $\mathbf{Y b}^{3+}$ ions (Yb:YAG) were grown using the Czochralski method with liquid recharge. The concentration of $\mathbf{Y b}^{3+}$ ions along the length of the crystal boule varied from 0 to $4 \mathrm{at} . \%$. The subsequent studies showed the existence of a limiting gradient along the length of the crystals connected with formation of the impurities.

Remote generation of electromagnetic waves in the terahertz (THz) by the volume of air medium gains increasing scientific interest due to the demand for this spectral range in solving various practical problems including those belonging to the nonlinear atmospheric optics. During self-focusing and filamentation of high-power femtosecond laser pulses in air, the source of THz radiation is the plasma of laser filaments. One of the main challenges of THz generation by a laser filament is increasing the value of optical energy conversion to the long-wavelength band. In this paper, we present the results of our studies on DC-biased THz generation during single-color filamentation in air of focused femtosecond Ti:Sapphire-laser pulses (800 nm, pulse energy up to 40 mJ). The distinctive feature of our study is that a femtosecond optical pulse propagates through a spatially-localized heated air layer containing randomly inhomogeneous refractive index perturbations, which mimics strong air turbulence. For the first time to our knowledge, we show, that the turbulent air layer formed at the beginning of the optical path allows increasing the yield of THz radiation up to 1.5 times due to the formation of multiple chaotically-arranged filaments resulting from random perturbations of the optical beam energy profile that reduces the subsequent THz (re)absorption in the filament plasma.

The work is aimed at identifying and substantiating criteria that indirectly or actually control ore objects in order to create a predictive neural network model of the metallogenic potential of southeastern Transbaikalia. For this purpose, geological, geophysical and cartographic materials were collected and processed, including the results of the analysis of remote sensing data. Statistical analysis of the array of collected data made it possible to establish a list of the minimum necessary information to identify criteria for the localization of polymetallic ore objects within the territory of southeastern Transbaikalia. As a result, thematic schemes have been prepared reflecting the relationship between the distribution of known polymetallic mineralization zones and the identified geological and spatial features. A correlation analysis was carried out between all the criteria in order to assess the suitability of using the selected features as input data for a future neural network model.

Remote control of high-intensity laser beams in the atmosphere is an important problem of atmospheric optics. It is of special interest for atmospheric sounding, where turbulence can affect beam propagation. We experimentally study the effect of a turbulent layer produced at the beginning of a laser radiation propagation path on the characteristics of the filamentation domain and generation of high-intensity plasma-free channels for laser beams 2.5 and 5 cm diameter, including under the phase control of the transverse beam structure with a deformable mirror. In the presence of turbulence, the beginning of multiple filamentation domain approaches, however, insignificantly (<10

The method of laser scanning is proposed and developed for the investigation of radiation wavefront distortion in active elements of high-power laser amplifiers. Optical path difference profile is calculated from simultaneously investigated temperature and inverted population distributions in an active element. Optical path difference profiles introduced by pumped active elements of high-power laser amplifier are studied.

This brief review presents Russian and foreign models of acute myocardial infarction (AMI), which are used to gain new knowledge about the pathophysiology of the development of this disease, as well as to search for sensitive and specific biomarkers of AMI and associated pathologies, including vascular cognitive disorders. However, modeling vascular cognitive disorders associated with AMI is a challenging task. Re-searchers need to take into account the additive effect of ischemia of striated muscles (myocardium or skeletal muscles) and central anesthetics during the simulation of AMI in experimental animals.

In world U production, the unconformity-related deposits currently yield ~24%. The main unconformity- related deposits were found in the Athabasca U-bearing province in the southwestern part of the Canadian Shield and Alligator Rivers Uranium Field of the North Australian Shield. The deposits are localized close to the surfaces of structural-stratigraphic unconformity in the bottom of sedimentary basins: Athabasca in Canada and Kombolgie in Australia. According to a series of geological–structural parameters of formation, the Canadian and Australian unconformity-related deposits significantly differ allowing their classification as subtypes. In the Canadian deposits, the ore bodies occur both above and beneath the unconformity surface of the Athabasca basin, whereas the ores of the Australian deposits are localized exclusively beneath the unconformity surface in rocks of the basement of the Kombolgie basin. This paper is devoted to the reconstruction of paleohydrodynamic formation conditions of the Australian unconformity-related deposits. The computer models of fluid migration of following three scenarios were successively considered during the analysis of fluid mass transfer processes: (i) thermal fluid convection in a fault zone with periodic upward and downward free thermal fluid convection, (ii) forced convective fluid migration at subcritical permeability and therefore the absence of free thermal convection in the fault zone, and (iii) mixed convection with upward and downward fluid movement along the fault zone. We concluded that the processes of periodic thermal convective fluid circulation in the fault zone contradict the idea of infiltration mechanism of the formation of the Australian unconformity-related deposits in fault zones in the basement of the Kombolgie basin. We, therefore, considered possible influence of facies zoning of a combined aquifer in the basement of clastic sediments of the Kombolgie Supergroup on paleohydrodynamics of the ore-bearing system, which played the role of a main migration pass for U-transporting fluids. The analysis of zonal distribution of primary sedimentation environments and later diagenetic transformations of rocks of aquifers and aquitards of this basin allowed us to substantiate an idea on leading influence of zonal decrease in permeability of rocks of the combined aquifer on a circulation structure of U-transporting fluids with the change in their lateral migration in the basement of sedimentary deposits of the Kombolgie Supergroup on the downward infiltration along a transverse zone of the ore-controlling fault. This circulation of the structure of U-transporting fluids was accepted as a hypothesis of paleohydrodynamic formation conditions of Australian unconformityrelated deposits exclusively in rocks of the basement of the Kombolgie basin. The additional computer calculations, however, showed that a trend of the directed change in the permeability of rocks along the lateral movement pass of U-transporting fluids is a trigger condition, which can be responsible both for the upward and downward fluid movement along the ore-bearing fault zone depending on the direction of the trend. In the Kombolgie basin in Australia, the direction of this trend depended on the change of facies conditions on the regional migration pass of diagenetic fluids, whereas the local topographic features of the unconformity surface could affect the Athabasca basin in Canada. At an alternative trend of variation in permeability along the lateral migration of U-transporting fluids, the proposed transport mechanism of the formation of the Australian unconformity-related deposits could probably contribute also to the formation both of infiltration and exfiltration Canadian unconformity-related deposits, which are described by a paleohydrodynamic interfault geothermal convection model.

The numerical model of the laser amplification process based on the nonlinear Schrödinger equation for systems with simultaneously high peak power and pulse repetition rate has been developed. A model describes the interaction of the amplified radiation and the active element in the frequency domain without loss of phase relationships between the corresponding spectral components. The model is verified by comparing experimental and simulated results.

Генерация электромагнитных волн в терагерцовом диапазоне представляет интерес в силу востребованности данного диапазона для решения многих прикладных задач. Плазма филамента, возникающего при самофокусировке лазерных импульсов фемтосекундной длительности, является источником ТГц излучения. В настоящей работе представлены результаты исследования ТГц излучения филаментом в условиях его распространения через слой с неоднородным показателем преломления. Показано, что сформированный в оптическом канале турбулентный слой повышает эффективность генерации ТГц излучения в 1,4 раза за счет случайного возмущения энергетического профиля пучка и формирования множественной филаментации. The generation of electromagnetic waves in the terahertz range is of interest due to the demand for this range in solving various applied problems. The filament plasma generated during the self-focusing of femtosecond laser pulses serves as a source of THz radiation. This work presents the results of the study of THz radiation from the filament while propagating through a layer with an inhomogeneous refractive index. It is shown that the turbulent layer formed within the optical channel increases the efficiency of THz radiation generation by 1.4 times due to random perturbation of the beam’s energy profile and the formation of multiple filamentation.

The aim of the research was to study the frequency of occurrence of anxiety and depression in first-year medical university students in the post-holiday period.Materials and methods. The study involved 70 first-year medical university students (average age 17,9 ± 1,31 years). The study was conducted as part of a periodic medical examination of participants during the first semester (in the early post-holiday period). The Hospital Anxiety and Depression Scale (HADS) was used.Results. The analysis of the answers to the questions of the HADS anxiety subscale showed that more than a third of the survey participants (38,6%) had anxiety disorders, of which more than half of the participants (51,9%) needed the advice of a clinical psychologist or psychotherapist. 21,4% of participants had a feeling of tension, 27,2% - fear, 24,3% - restless thoughts, 17,1% - inability to relax, 22,8% - internal tension or trembling, 40% - restlessness, 31,4% - panic. Analysis of answers to questions on the HADS depression subscale indicated that 22,9% of students had depressive disorders, of which more than a third (37,5%) needed the advice of a clinical psychologist or psychotherapist. 27,1% of participants had a decrease/lack of pleasure from something that used to bring positive emotions, 10% - inability to laugh, 15,7% - lack of a sense of cheerfulness, 20% - slowness, 15,7% - unwillingness to monitor their appearance, 18,6% - decreased sense of satisfaction from hobbies, 20% - decreased feelings of pleasure from a good book, radio or TV program.Conclusion. The expansion of the standard scope of periodic medical examination made it possible to screen the psycho-emotional state of students in the post-holiday period of the autumn semester and identify a risk group for the development and increase of existing anxiety-depressive disorders during the educational process, which can have an adverse effect on both the quality of life of students and the effectiveness and success of training.

Для дистанционного зондирования атмосферы уже долгое время активно применяется метод флуоресцентной спектроскопии (LIFS), который является одним из наиболее чувствительных и селективных методов определения малых концентраций веществ. Применение мощных фемтосекундных лазерных источников для дистанционного зондирования атмосферы методом флуоресцентной спектроскопии способствует развитию лидаров нового поколения. Целью исследований было изучение возможности применения интенсивных световых каналов, сформированных турбулентным экраном для реализации метода флуоресцентной спектроскопии жидкофазного аэрозоля. Показана возможность удаленного детектирования спектров флуоресценции и увеличения регистрируемого свечение при сегментировании лазерного пучка. For atmospheric remote sensing, the method of fluorescence spectroscopy (LIFS) has been actively used for a long time, which is one of the most sensitive and selective methods for determining trace concentrations of substances. The use of powerful femtosecond laser sources for remote atmospheric sensing by fluorescence spectroscopy contributes to the development of next-generation lidars. The purpose of the research was to investigate the feasibility of using intense light channels formed by a turbulent screen for implementing the fluorescence spectroscopy method for liquid-phase aerosol. The possibility of remote detection of fluorescence spectra and increased registered luminescence due to segmentation of the laser beam was demonstrated.

This paper highlights the most important results achieved at the spherical tokamak Globus-M2 with a high magnetic field. This paper also covers the most important topics of fusion research: thermal energy confinement in regimes with neutral beam injection, toroidal Alfvén eigenmode and correspondent fast ions confinement issues, L-H transition, turbulence suppression and edge-localized modes' behavior, experimental and theoretical study of regimes with nitrogen seeding that allow to significantly reduce thermal loads on the divertor plates, and experiments and simulations of lower hybrid current drive. The research results provide the basis for the next step toward a fusion neutron source—the development of the Globus-3 spherical tokamak.

The results of a comprehensive detailed study of the vein structure, mineral zoning of veins, and mineral typomorphism of the Shakhtama deposit obtained on the basis of new samples from poorly studied horizons are given. The results obtained show that the Mo resources of the deposit are far from being exhausted, and the typomorphic features of ore minerals indicate that base metal mineralization associated with Au (Ag), also continues to a depth, along with Mo. The presence of rare Sr mineral, svanbergite, in the Shakhtamа deposit and the typomorphic properties of ore minerals testify in favor of the near-surface origin of the exposed mineralization. The succession of mineral formation has been established. Based on the study of ore and metasomatic zonality, fluid inclusions and isotopic data, as well as the composition of structural impurities in molybdenite, conclusions were made of the formation conditions of ore mineralization in a porphyry ore-forming system.

This work is aimed at the practical application of satellite imagery data for the selection of promising areas during geological exploration work in conditions of medium-low mountainous terrain and a sharply continental climate. The processing results and analysis of WorldView-2 data within the Talmanskaya area are presented in order to identify zones of hydrothermal-metasomatic changes in rocks that are promising for identifying of gold-polymetallic mineralization. The choice of the study area is due to sufficient geological knowledge and the absence of man-made formations that affect the result of processing satellite imagery materials. To increase the spectral information content of the WorldView-2 data, the spectral channel ratio method was used, as a result of which a pseudocolor RGB composite was created that displays the spectral characteristics of objects on the Earth’s day surface, in particular, minerals of the oxide/hydroxide group containing transition iron ions (Fe 3+ and Fe 3+ /Fe 2+ ). A comparison of satellite data processing results along with geological information made it possible to identify spectral anomalies as indicators of the presence of near-ore changes, which are an important search criterion for hydrothermal deposits.

In improved confinement (in H-mode) in the Globus-M2 tokamak, the development of edge-localized modes (ELMs) is accompanied by the appearance of filament structures. The use of the Doppler backscattering (DBS) method allowed to determine filament parameters both during ELMs triggered by sawtooth crashes and during independent ELMs. It is shown that the number of filaments observed during synchronized ELMs is greater and their area of observation is wider. The velocity of the filaments during all types of ELMs observed on Globus-M2 ELM is higher than on the previous tokamak Globus-M. Filaments developing immediately before an ELM burst are characterized by smaller amplitudes and velocities. Comparing the results of two diagnostic techniques, DBS and poloidal correlation Doppler reflectometry, to determine the velocity of such filaments, shows a similarity of the measured values, which may indicate linear scattering off these filaments.

The development of a refined conceptual model for the generation of volcanic-related uranium deposits includes studies in the character of magmatic, hydrothermal-metasomatic, and filtration-transport processes, as well as of the physicochemical conditions favoring the transport and deposition of uranium. We consider these issues using the examples of the Streltsovka caldera and the eponymous ore field in eastern Transbaikalia, the Xiangshan volcanic structure in South China, and the McDermitt caldera in the western United States (Oregon and Nevada). According to the IAEA classification (Geological Classification …, 2018), these ore fields and deposits are of the volcanic-related type, while the Streltsovka and the Xiangshan ore field show a combination of the volcanic-related type in the volcanic-sedimentary cover and the granite-related type at the basement. Most industrially viable uranium deposits of the volcanic-related type were formed in the regions listed above during Mesozoic and Cenozoic times (although we know of older, Paleozoic objects of the type). Although the time spans in which ore-bearing volcanic-related edifices were formed are different, many features in the occurrence of magmatic, hydrothermal, and filtration transport processes in these edifices are rather similar. It is commonly supposed that these features are due to a common effect of intraplate tectonic regimes or to the evolution of outer parts in the ocean-continent zones where magmatic activity produced volcanism of the bimodal series in the dominant basites–acid volcanics–basites sequence, while the migration of uranium-transporting fluids was controlled by a joint action of seismogeodynamic and thermal convective processes.

The purpose of this scientific work is to study the potential of neural network technologies in the field of extracting linear structures from Shuttle Radar Topography Mission (SRTM) digital terrain models (DTMs). Linear structures, also known as lineaments, play an important role in the verification of known faults, the identification of fault-fracture structures, and detailing the framework of discontinuous faults, as well as in the exploration of mineral resources. Their accurate and effective extraction in solving the depicted problems is of fundamental importance. The use of neural network technologies provides a number of advantages over sequential algorithms, including the ability to search for universal criteria for identifying lineaments based on a training sample. This paper considers a comprehensive innovative methodology that includes several key stages. The first stage is the author’s method of data preparation, which helps ensure the quality of the training sample and minimize the impact of noise. The second stage is to develop an algorithm for vectorizing the results of the neural network operation, which allows one to easily export the results (lineaments) to a geographic information system (GIS). The third stage provides a method for minimizing the noise component of the training sample and optimizing the selection of synaptic weighting coefficients by retraining the neural network using simulated data reflecting various localization conditions of the lineaments. To verify the results, a spatial comparison of linear structures extracted by the neural network and lineaments isolated by the operator is carried out. The results of this comparison demonstrate the high potential of the proposed approach and show that the use of neural network technologies is a topical and promising approach for solving the problem of extracting linear structures from digital models of the terrain. Positive conclusions are made about the expediency of using the results obtained for their practical application in the field of earth sciences.

Methods of mathematical modeling were used for estimating the influence of tectonic fault activation on the safety of a facility for final isolation of high-level radioactive waste at the Yeniseiskii site (Krasnoyarsk region). A 3D model of radionuclide transport by groundwater was considered taking into account the heterogeneous rock permeability. Faults of different orientations were considered. We showed that the formation of new near-meridional faults or activation of ancient ones did not exert a substantial influence on the velocity of radioactive pollution propagation in an underground medium. Near-latitudinal faults can affect the radionuclides to a larger extent. We considered the possibility to confine this influence due to the technogenic decrease in the rock permeability within a relatively short interval of the fault zone.

Absorbed power of the neutral-injection beam in spherical tokamaks Globus-M/M2 is estimated numerically. Deceleration of fast particles is simulated by means of the NUBEAM code. The signal of analyzer of charge-exchange atoms is simulated by means of the FIDASIM code using the distribution function of fast ions calculated by means of the NUBEAM code. Comparison of calculated and experimental signals allowed determining the degree of influence of instabilities on confinement of fast particles along with absorbed beam power.

This paper considers the suitability of using multispectral remote sensing data from the Landsat-8 satellite for conducting regional geological and mineralogical mapping of the territory of southeastern Zabaykalsky krai (Russia) under conditions of medium–low mountain relief and continental climate. To increase the spectral information content of Landsat-8 satellite data, statistical processing algorithms are used, including principal component analysis (PCA), minimum noise fraction (MNF), and independent component analysis (ICA). Statistical processing results are compared with the classes of geological materials: minerals of the oxide/hydroxide group containing transitional iron ions (Fe 3+ and Fe 3+ /Fe 2+ ); a group of clay minerals containing Al-OH and Fe, Mg-OH; and minerals containing divalent iron ion (Fe 2+ ) and vegetation cover. Pseudocolor RGB composites are generated and interpreted, reflecting the distribution and multiplication of classes of geological materials. To build a prospectivity scheme for the discovery of the minerals, the integration of informative thematic layers is carried out using a fuzzy logic model. The resulting scheme is compared with geological information, and positive conclusions are made about the suitability of territory for further remote studies on mapping hydrothermally altered zones and hypergenesis products in order to localize areas that are promising for revealing hydrothermal–metasomatic mineralization.