Bulk-boundary correspondence in three dimensional topological insulators

We discuss the relation between bulk topological invariants and the spectrum of surface states in three dimensional non-interacting topological insulators. By studying particular models, and considering general boundary conditions for the electron wavefunction on the crystal surface, we demonstrate that using experimental techniques that probe surface states, only strong topological and trivial insulating phases can be distinguished; the latter state being equivalent to a weak topological insulator. In a strong topological insulator, only the {\it parity} of the number of surface states, but not the number itself, is robust against time-reversal invariant boundary perturbations. Our results suggest a \z definition of the bulk-boundary correspondence, compatible with the \z classification of topological insulators.Comment: TeXLive (Unix), revtex4-1, 7 pages, 3 figure

Effect of year-round training on parameters of heart rate variability, central hemodynamics and physical working capacity in short-distance swimmers

Dynamic examination of athletes is of great interest for sports medicine specialists, as it allows measuring changes in athletes’ functional state in parallel with increasing athletic performance in a one-year training cycle. The aim of the work is to assess dynamic changes in parameters of heart rate variability, central hemodynamics and physical performance in short-distance swimmers during preparatory and competitive periods of the training process. Materials and methods. The swimmers (n = 94) qualified from the second-class sport qualification to Master of Sports of International Class were examined during the preparatory and competitive periods of the training process. Short ECG recordings of 5 minutes were used for the heart rate variability (HRV) analysis according to the International Standard. Results. In the preparatory period, the autonomic equilibrium index had a mean value of 3.104 ± 0.494 1/s2, and in the competitive period – 2.459 ± 0.248 1/s2 (P = 0.295). The initial distribution of athletes depending on the value of autonomic tone, according to the classification proposed by R. M. Bayevskiy, had the following ratio in the preparatory period: 75.0 % / 20.0 % / 5.0 %, vagotonic, normotonic and sympathotonic individuals, respectively, statistically significantly indicating the prevalence of athletes with vagotonia over normotonic individuals (P = 0.0005). In the competitive period, this ratio was 60.0 % / 40.0 % / 0 %. The central hemodynamic indices showed a downward trend as evidenced by a decrease in the cardiac index from 2.954 ± 0.126·l·min-1·m-2 to 2.862 ± 0.088 l‧min-1‧m-2 (Р = 0.510), although these values matched to the eukinetic circulatory type (CT) during both training periods. However, the ratio of hypokinetic, eukinetic and hyperkinetic CT in the preparatory period was 45.0 % / 45.0 % / 10 0 %, and in competitive period – 45.0 % / 55.0 % / 0 %, respectively. The mean value of physical working capacity (PWC170/kg) in the preparatory period was 15.54 ± 0.66 kgm·min-1·kg-1, and in the competitive period it was 18.09 ± 0.53 kgm·min-1·kg-1, making an increase of 16.41 % (Р = 0.0001). The functional state index (FSI) increased significantly by 25.08 % from 5.558 ± 0.322 r. u. to 6.952 ± 0.272 r. u. (Р = 0.00001). The correlation analysis during the preparatory period showed a significant positive correlation between Mo and PWC170/kg (r = 0.46, P = 0.040), ARI and CI (r = 0.50, P = 0.026), IARP and CI (r = 0.53, P = 0.017), stress-index and SI (r = 0.52, P = 0.019) and negative – between Mo and CI (r = -0.56, P = 0.009). In the competitive period, the general tendency of correlation interaction was remained, as evidenced by revealed positive relationships between Mo and FSI (r = 0.53, P = 0.017), ARI and SI (r = 0.51, P = 0.020). Conclusions. Short-distance swimmers in the competitive period had significantly higher level of physical working capacity (by 16.4 %), the functional state index (by 25.1 %), as well as parasympathetic tone of ANS in comparison with the preparatory period. The above-mentioned hemodynamic changes and autonomic balance indicators were associated with the increase in athletic performance: 4 (20 %) swimmers qualified for the title of Master of Sports of Ukraine, 2 (10 %) swimmers – for Candidate Master of Sports, and 2 (10 %) swimmers – for first-class sport qualification

MECHANICAL PROPERTIES OF HIGH-POROUS TITANIUM ALLOY FOR BONE IMPLANTS

На цилиндрических образцах из сплава Ti–6Al–4V, полученного методом послойного лазерного сплавления из порошка со средней дисперсностью 23,5 мм, определены механические свойства в соответствии с международным стандартом ISO 13314:2011 для пористых металлических материалов. Показано, что модуль Юнга образцов с пористостью 55 % на порядок ниже, чем у сплошного металла.Mechanical properties of cylindrical samples of Ti–6Al–4V, fabricated using selective laser melting of powder with mean value of particle dimensions of 23.5 mm, were determined according to international standard ISO 13314:2011 for porous metals. Strength and elastic characteristics of porous samples (porosity of 55%) were shown to be lower then for bulk metal by an order of magnitude.Работа выполнена при финансовой поддержке гранта Российского научного фонда на выполнение проекта № 16-15-00176 «Установление закономерностей остеоинтеграции медицинских имплантатов на основе аддитивного производства с биоактивным покрытием»

About the first experiment at JINR nuclotron deuteron beam with energy 2.52 gev on investigation of transmutation of I-129, NP-237, PU-238 and PU-239 in the field of neutrons generated in pbtarget with U-blanket

The experiment described in this communication is a part of the scientific program „Investigations of physical aspects of electronuclear method of energy production and transmutation of radioactive waste of atomic energetic using relativistic beams from the JINR Synchrophasotron/Nuclotron“ - the project „Energy plus Transmutation“. The performing of the first experiment at deuteron beam with energy 2.52 GeV at the electronuclear setup which consists of Pb-target with U-blanket (206.4 kg of natural uranium) and transmutation samples and its preliminary results are described. The hermetic samples of isotopes of I-129, Np-237, Pu-238 and Pu-239 which are produced in atomic reactors and industry setups which use nuclear materials and nuclear technologies were irradiated in the field of electronuclear neutrons produced in the Pbtarget surrounded with the U-blanket setup “Energy plus transmutation”. The estimations of its transmutations (radioecological aspect) were obtained in result of measurements of gamma activities of these samples. The information about space-energy distribution of neutrons in the volume of the Pb-target and the U-blanket was obtained with help of sets of activation threshold detectors (Al, V, Cu, Co, Y, In, I, Ta, Au, W, Bi and other), solid state nuclear track detectors, He-3 neutron detectors and nuclear emulsions

Как придать импульс развитию российской экономики: приоритеты действий (предложения к Основным направлениям деятельности Правительства РФ до 2024 г.)

This report was prepared by the staff of the Institute for Economic Forecast of the Russian Academy of Sciences and the Financial University under the Government of the Russian Federation. It gives suggestions to implement priority measures to facilitate the transfer the Russian economy to the direction defined by the Decree of the President of the Russian Federation (est. May 7, 2018). The report also highlights priority directions of the economic policy, primarily in investment activity, development of the domestic market, as well as financial and organizational support for the suggested actions.В докладе, подготовленном сотрудниками Института народнохозяйственного прогнозирования РАН и Финансового университета при Правительстве Российской Федерации, представлены предложения по первоочередным мерам, способствующим переводу российской экономики на траекторию, определенную Указом Президента Российской Федерации от 07.05.2018. Выделены приоритетные направления  экономической политики, прежде всего, в инвестиционной деятельности, развитии внутреннего рынка, а также финансового и организационного обеспечения предлагаемых мер

Клиническая эффективность и безопасность применения ингаляционного простациклина у больных с инфекцией, вызванной SARS-CoV-2 (проспективное сравнительное исследование)

Aim. In this study we evaluated clinical effectiveness and safety of nebulized prostacyclin in patients with Novel Coronavirus Disease (SARS-CoV-2). Materials and methods: We have included 44 male patients with moderate PCR confirmed SARS-CoV-2 infection in this study. Control group consisted of 23 patients treated with nebulized prostacyclin (PGI2). besides standard therapy. We compared intensiveness and duration of infectious intoxication syndrome, duration of fever, cough as well as SpO2 level, complete blood count and chemokine status values. Results: Statistically significant difference in duration of fever, cough, intensiveness and duration of infectious intoxication syndrome were observed. Lymphocyte and platelet counts were significantly higher in control group We have also noticed significantly lower level of proinflammatory mediators and C4-complement component in control group. Only 1 adverse effect associated with inhaled prostacyclin was reported. Conclusion. Nebulized prostacyclin showed therapeutic efficacy and good safety profile in adults with moderate COVID-19.Цель: оценка клинической эффективности и безопасность ингаляционного простациклина у пациентов с новой коронавирусной инфекцией (SARS-CoV-2). Материалы и методы: в исследование были включены 44 пациента мужского пола с подтвержденной новой коронавирусной инфекцией среднетяжелого течения. Опытную группу составили 23 пациента, которым, помимо стандартной терапии, был назначен ингаляционный простациклин (PGI2). Клиническая эффективность илопроста была оценена по длительности и выраженности общеинфекционных синдромов (интоксикации, лихорадки), длительности кашля, уровню насыщения крови кислородом, значениям параметров общеклинического анализа крови, показателю иммунологического статуса пациентов. Результаты: получено статистически значимое снижение длительности лихорадки, продолжительности кашля, выраженности и длительности синдрома общей инфекционной интоксикации в опытной группе. Также отмечено, что у этих пациентов средние значения количества лимфоцитов, тромбоцитов достоверно увеличивалось, а значение СОЭ снижалось. Средние значения провоспалительных цитокинов, хемокинов, а также С4-компонента комплемента были статистически значимо ниже, чем у больных COVID-19 в группе сравнения. Нежелательные реакции, связанные с инга ляционной терапией простациклином, были отмечены в 1 наблюдении. Заключение: показана терапевтическая эффективность и хороший профиль безопасности ингаляционного простациклина у пациентов с COVID-19 средней степени тяжести

Расчетное исследование влияния перегрева алюминиевого расплава на теплообмен при непрерывном совмещенном процессе литья-прессования

The article presents the results of a numerical study of temperature-time dependences in continuous combined casting and pressing of the AK12 experimental aluminum alloy, which has a different overheating temperature, in the time interval from start-up to the moment of the unit reaching the stationary thermal regime. Calculations are carried out on the basis of a three-dimensional computer model of complex heat transfer in the unit of a new design equipped with a horizontal carousel crystallizer. Theoretical studies are conducted to determine the influence of superheating of poured aluminum melt on the processes of unsteady heat transfer. The influence of the nature of heat transfer in the transient thermal regime on the temperature field of the solidifying melt at different distances from the pour point is determined. It is shown that as the crystallizer heats up in the transition process, the asymmetry of the temperature field in the control section of metal increases near the pressing tool with the shift of the maximum temperature region to the crystallizer contac surface. It is found that the transition process duration when starting the unit in a cold state until it reaches a stationary thermal regime depends on the temperature of poured melt. The maximum limit of the overheating value is determined, above which poured metal, when implementing the technology of continuous combined casting and pressing, aluminum melt does not solidify in the crystallizer and forced cooling of unit elements must be arranged. The influence of melt overheating on the pattern of the temperature field along the crystallizer cross section over the entire period of the transient thermal process is estimated. Design measures to ensure rational temperature conditions of bearings during the unit operation are determined.Приведены результаты численного исследования температурно-временных зависимостей при непрерывном совмещенном процессе литья и прессования опытного алюминиевого сплава АК12, имеющего различную температуру перегрева, в интервале времени от пуска до момента выхода установки на стационарный тепловой режим. Расчеты выполнены на основе трехмерной компьютерной модели сложного теплообмена в установке новой конструкции, оснащенной горизонтальным карусельным кристаллизатором. Проведены теоретические исследования воздействия перегрева заливаемого алюминиевого расплава на процессы нестационарного теплообмена. Определено влияние характера теплообмена в переходном тепловом режиме на температурное поле затвердевающего расплава на различном его удалении от места заливки. Показано, что по мере разогрева кристаллизатора в переходном процессе возрастает несимметричность температурного поля в контрольном сечении металла вблизи инструмента прессования со сдвигом области с максимальной температурой к контактирующей поверхности кристаллизатора. Установлено, что продолжительность переходного процесса при пуске установки из холодного состояния до достижения ею стационарного теплового режима зависит от температуры заливаемого расплава. Определен максимальный предел величины перегрева заливаемого металла, выше которого при реализации технологии непрерывного совмещенного процесса литья-прессования алюминиевый расплав не затвердевает в кристаллизаторе, и требуется организация принудительного охлаждения элементов установки. Проведена оценка влияния перегрева расплава на характер температурного поля по сечению кристаллизатора во всем периоде переходного теплового процесса. Предложены конструктивные мероприятия, обеспечивающие в ходе эксплуатации установки рациональные температурные условия работы подшипников

Design analysis of the thermal condi-tions for continuous casting and extru-sion based on a conform unit with hori-zontal mold wheel

The proximity mathematical model of complex heat exchange has been developed in the area of a conform unit a with horizontal mold for the continuous casting and extrusion of non-ferrous metals. The dynamics of the lead alloy extrusion have been studied at an experimental laboratory unit. The design temperatures for metal and elements of a prototype unit have been identifie