The nonlinear effects in 2DEG conductivity investigation by an acoustic method

The parameters of two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure were determined by an acoustical (contactless) method in the delocalized electrons region ($B\le$2.5T). Nonlinear effects in Surface Acoustic Wave (SAW) absorption by 2DEG are determined by the electron heating in the electric field of SAW, which may be described in terms of electron temperature $T_e$. The energy relaxation time $\tau_{\epsilon}$ is determined by the scattering at piezoelectric potential of acoustic phonons with strong screening. At different SAW frequencies the heating depends on the relationship between $\omega\tau_{\epsilon}$ and 1 and is determined either by the instantaneously changing wave field ($\omega\tau_{\epsilon}$$<1$), or by the average wave power ($\omega\tau_{\epsilon}$$>1$).Comment: RevTeX, 5 pages, 3 PS-figures, submitted to Physica Status Sol.(Technical corrections in PS-figs

The assessment of the level of digitalization and digital transformation of oil and gas industry of the Russian Federation

Digitalization and digital transformation of companies have turned from global trends to an urgent need. Thanks to digitalization and digital transformation, organizations can overcome the times of crisis, the times of lockdowns with less losses and respond more effectively to any adverse changes in the external environment. The assessment of the level of digitalization and digital transformation allows to determine how fast the processes of introducing digital technologies and optimizing processes with digital solutions proceed, both in companies and across the industry as a whole. The article provides an analysis with the systematization of foreign and domestic methods, methodological approaches, methods for assessing the digitalization level and digital transformation, as well as reveals their positive and negative aspects. Based on a comparative analysis, an improved author-developed methodological toolkit is proposed for assessing the level of digitalization and digital transformation, alleviating the disadvantages of the existing methodological experience. The approbation of the author-developed methodological toolkit was performed using the oil and gas industry as an example; the following companies, being the industry leaders, were analysed: PJSC “Lukoil”, PJSC “NK “Rosneft”, PJSC “Gazprom”, and PJSC “Tatneft”. According to the results, the digitalization and digital transformation processes of the domestic oil and gas industry are insufficiently dynamic. It was found that in the period from 2016 to 2020, the Russian Federation industry leaders were in the following order from the most advanced to the least advanced in terms of the digitalization level and digital transformation: PJSC “Gazprom” topped the list; PJSC “NK “Rosneft” was second; PJSC “Lukoil” was the third largest company, and PJSC “Tatneft” held the fourth position

Regional Differences in Life Expectancy in Russia Through the Lens of Epidemiological Transition

Received 16 February 2024. Accepted 13 May 2024. Published online 21 July 2024.An immense territory of Russia with several climatic zones and, accordingly, a fundamentally different styles of life, inevitably results in pronounced varieties in the levels and structure of mortality across the regions of the country. Since the scale and sustainability of differences in mortality in Russia can be considered an entire epidemiological epoch, the evaluation of them through the lens of epidemiological transition seems methodologically appropriate. Regional differences are regarded as a kind of projection of evolution in time, though taking into account modern realities. The analysis of regional differences in mortality is based on such indicators as life expectancy, structure of mortality, i.e., predominantly endogenous to exogenous causes of death ratio, as well as the average age of death from predominantly endogenous causes calculated on the basis of life tables by cause of death. The study showed that according to the periodization of epidemiological transition only Moscow and St. Petersburg are at the final phase of the 3rd stage and are moving to the 4th stage of epidemiological development. Meanwhile, the burden of exogenous and preventable pathologies precludes the completion of the 3rd stage in the regions with high life expectancy according to Russian criteria. The stadial nature of epidemiologic development of Russian regions is currently conditioned by socio-economic and medical determinants, with more pressing medical determinants in regions with high and medium levels of life expectancy and socio-economic factors prevailing in regions with low life expectancy

MINERAL AND RAW MATERIALS BASE OF THE URAL FEDERAL DISTRICT: ON THE WAY TO A SUSTAINABLE SUBSOIL USE (USING SOLID COMMERCIAL MINERALS AS AN EXAMPLE)

Relevance. The process of sustainable use of mineral resources, which is one of the priority areas of both rehabilitation, extraction of natural resources, and the state policy in the field of national security, is of particular importance. Currently, the state regulation of subsoil use faces a number of pressing problems: first, the process of recovering the exhaustible resources of solid commercial minerals (SCM) is hampered; secondly, penetration the sixth techno-economic paradigm and the growing “fourth industrial revolution” dictate their terms for organizing a sustainable subsoil use, which implies achieving a balance of common development factors (resource, “green”, social, economic ones) using high technologies, artificial intelligence devices, robotics and other innovative solutions. In order to implement sustainable subsoil use at the regional and country levels, it is necessary to diagnose the state of the mineral resources base (MRB). This evaluation can become a functional tool for state regulation of subsoil use. Purpose of the work is to analyze the state of the mineral resource base of the subsoil use of the Ural Federal District (UFD) from the point of view of fulfilling the condition of balance (security). Results. The basic principle is defined – the condition for achieving a balance of subsoil use; peculiarities and problems in the management of subsoil use of the Ural Federal District on the basis of the analysis of the Ural Federal District and the system for financing geological exploration in the UFD; some possible directions for meeting the condition for achieving a balance are identified. Conclusion. The exhaustion of the region’s MRB of SCM and the priority of the extraction of fuel and energy raw materials contribute to a reduction in federal funding for the development of the MRB of SCM of the Ural Federal District. The subsoil users of the region are provided with reserves, to some extent, and they are not interested in carrying out further prospecting works. The foregoing demonstrates the need to develop and implement some balanced solutions for further stage of geological study of the MRB of SCM in the framework of public private partnerships using industry regulation mechanisms to achieve a sustainable supply of producers with their own raw materials

EVENTS AS A MECHANISM FOR THE DEVELOPMENT OF INCLUSIVE EDUCATION IN HIGHER EDUCATION

Повышение качества жизни людей с инвалидностью и с ограниченными возможностями здоровья и их успешная социализация во многом зависят от получения ими качественного высшего образования. Российские вузы принимают активное участие в формировании инклюзивной образовательной среды, являются участниками различных мероприятий, в рамках которых происходит обмен опытом в организации и успешной реализации инклюзивных практик, которые позволяют превратить человека с ограниченными возможностями в субъект, способный стать полноценным участником образовательной деятельности. В статье еvent-мероприятия рассматриваются как механизм развития инклюзивного образования в высшей школе. Основная задача авторов статьи – обобщить опыт организации и проведения event-мероприятий в инклюзивной образовательной практике Уральского федерального университета.Improving the quality of life of people with disabilities and with limited abilities and their successful socialization largely depend on their obtaining a high-quality higher education. Russian universities take an active part in the formation of an inclusive educational environment. They are participants in various events, within the framework of which there is an exchange of experience in the organization and successful implementation of inclusive practices that make it possible to turn a person with disabilities into a subject capable of becoming a full-fledged participant in educational activities. In the article, events are considered as a mechanism for the development of inclusive education in higher education. The main task of the authors of the article is to summarize the experience of organizing and conducting events in the inclusive educational practice of the Ural Federal University

Electron localization in sound absorption oscillations in the quantum Hall effect regime

The absorption coefficient for surface acoustic waves in a piezoelectric insulator in contact with a GaAs/AlGaAs heterostructure (with two-dimensional electron mobility $\mu= 1.3\times 10^5 cm^2/V\cdot s)$ at T=4.2K) via a small gap has been investigated experimentally as a function of the frequency of the wave, the width of the vacuum gap, the magnetic field, and the temperature. The magnetic field and frequency dependencies of the high-frequency conductivity (in the region 30-210 MHz) are calculated and analyzed. The experimental results can be explained if it assumed that there exists a fluctuation potential in which current carrier localization occurs. The absorption of the surface acoustic waves in an interaction with two-dimensional electrons localized in the energy "tails" of Landau levels is discussed.Comment: RevTeX 6 pages+6 EPS pic

Experimental study of weak antilocalization effect in a high mobility InGaAs/InP quantum well

The magnetoresistance associated with quantum interference corrections in a high mobility, gated InGaAs/InP quantum well structure is studied as a function of temperature, gate voltage, and angle of the tilted magnetic field. Particular attention is paid to the experimental extraction of phase-breaking and spin-orbit scattering times when weak anti- localization effects are prominent. Compared with metals and low mobility semiconductors the characteristic magnetic field $B_{tr} = \hbar/4eD \tau$ in high mobility samples is very small and the experimental dependencies of the interference effects extend to fields several hundreds of times larger. Fitting experimental results under these conditions therefore requires theories valid for arbitrary magnetic field. It was found, however, that such a theory was unable to fit the experimental data without introducing an extra, empirical, scale factor of about 2. Measurements in tilted magnetic fields and as a function of temperature established that both the weak localization and the weak anti-localization effects have the same, orbital origin. Fits to the data confirmed that the width of the low field feature, whether a weak localization or a weak anti-localization peak, is determined by the phase-breaking time and also established that the universal (negative) magnetoresistance observed in the high field limit is associated with a temperature independent spin-orbit scattering time.Comment: 13 pages including 10 figure

Magnetic-field-dependent zero-bias diffusive anomaly in Pb oxide-n-InAs structures: Coexistence of two- and three-dimensional states

The results of experimental and theoretical studies of zero-bias anomaly (ZBA) in the Pb-oxide-n-InAs tunnel structures in magnetic field up to 6T are presented. A specific feature of the structures is a coexistence of the 2D and 3D states at the Fermi energy near the semiconductor surface. The dependence of the measured ZBA amplitude on the strength and orientation of the applied magnetic field is in agreement with the proposed theoretical model. According to this model, electrons tunnel into 2D states, and move diffusively in the 2D layer, whereas the main contribution to the screening comes from 3D electrons.Comment: 8 double-column pages, REVTeX, 9 eps figures embedded with epsf, published versio

Interaction effects and phase relaxation in disordered systems

This paper is intended to demonstrate that there is no need to revise the existing theory of the transport properties of disordered conductors in the so-called weak localization regime. In particular, we demonstrate explicitly that recent attempts to justify theoretically that the dephasing rate (extracted from the magnetoresistance) remains finite at zero temperature are based on the profoundly incorrect calculation. This demonstration is based on a straightforward evaluation of the effect of the electron-electron interaction on the weak localization correction to the conductivity of disordered metals. Using well-controlled perturbation theory with the inverse conductance $g$ as the small parameter, we show that this effect consists of two contributions. First contribution comes from the processes with energy transfer smaller than the temperature. This contribution is responsible for setting the energy scale for the magnetoresistance. The second contribution originates from the virtual processes with energy transfer larger than the temperature. It is shown that the latter processes have nothing to do with the dephasing, but rather manifest the second order (in $1/g$) correction to the conductance. This correction is calculated for the first time. The paper also contains a brief review of the existing experiments on the dephasing of electrons in disordered conductors and an extended qualitative discussion of the quantum corrections to the conductivity and to the density of electronic states in the weak localization regime.Comment: 34 pages, 13 .eps figure