Morphological Instability of Steps During Crystal Growth from Solution Flow

It is shown that step moving to meet solution flow can be unstable against lateral perturbations. The instability of long-wavelength perturbations occurs at values of the solution flow intensity less than some critical value depending on the step velocity. At given intensity of the solution flow, the instability comes at the step velocity exceeding a critical velocity. Decay of short-wavelength fluctuations is conditioned by the line tension of the step. The step moving along the solution flow is laterally stable at all values of the step velocity and the intensity of the solution flow. The overlapping diffusion field of the neighbour steps suppresses the lateral instability but it gives an instability of the step train against doubling of the period, i.e. neighbouring steps are attracted. The equidistant train moving to meet the solution flow is stable against the period variations.Comment: 22 pages, REVTEX (will be appeared in Journal of Crystal Growth

Бесконечномерные римановые многообразия с равномерной структурой

Проблематика. Для розв’язку крайових задач на нескінченновимірних ріманових многовидах, зокрема для дослідження задачі Діріхле, суттєвою видається їх метрична повнота. Гарантувати її в загальному випадку не уявляється можливим, а отже, виникає питання наведення її достатніх умов. Мета дослідження. Метою роботи є наведення достатніх умов метричної повноти нескінченновимірних ріманових многовидів і суттєвих прикладів, що ці умови реалізують. Методика реалізації. Застосовано базові результати функціонального аналізу та сучасної диференціальної геометрії. Результати дослідження. Сформулювано і доведено достатні умови метричної повноти нескінченновимірних ріманових многовидів. Доведено, що ці умови реалізуються на поверхнях рівня скінченної корозмірності в гільбертовому просторі з певним обмеженням на перші і другі похідні відповідних функцій. Висновки. Отримані достатні умови метричної повноти ріманових многовидів – рівномірнсть структури – видаються перспективними, оскільки реалізуються щонайменш на одному досить широкому класі поверхонь в гільбертовому просторі. Доцільним вбачається розроблення підходів до розгляду крайових задач на таких нескінченновимірних ріманових многовидах.Background. Solving boundary value problems on infinitedimensional Riemmanian manifolds, in particular researching Dirichlet problem, seems to demand for metric completeness. It does not appear to be feasible to state metric completeness in the general case, hence stems the issue of giving sufficient conditions of it. Objective. Giving sufficient conditions of metric completeness of infinitedimensional Riemmanian manifolds and essential examples that would satisfy them. Methods. Basic results of functional analysis and contemporary differential geometry are used. Results. Sufficient conditions of infinitedimensional Riemmanian manifolds completeness have been formulated and proved. It has been proved that given conditions are satisfied for by level surfaces of finite codimension with certain bounds on first and second derivatives of the respective functions. Conclusions. The Sufficient conditions of Riemmanian manifolds completeness — structure uniformity — look to be promising, since they are satisfied for at least by one relatively wide class of surfaces in Hilbert’s space. In terms of future researches, it now appears to be reasonable to devise approaches to considering boundary value problems on such infinitedimensional Riemmanian manifolds.Проблематика. Для решения краевых задач на бесконечномерных римановых многообразиях, в частности для исследования задачи Дирихле, существенной видится их метрическая полнота. Гарантировать ее в общем случае не представляется возможным, а следовательно, возникает вопрос приведения ее достаточных условий. Цель исследования. Целью работы является приведение достаточных условий метрической полноты бесконечномерных римановых многообразий и существенных примеров, которые эти условия реализуют. Методика реализации. Использованы базовые результаты функционального анализа и современной дифференциальной геометрии. Результаты исследования. Сформулированы и доказаны достаточные условия метрической полноты бесконечномерных римановых многообразий. Доказано, что данные условия реализуются на поверхностях уровня конечной коразмерности в гильбертовом пространстве с некоторыми ограничениями на первые и вторые производные соответствующих функций. Выводы. Полученные достаточные условия метрической полноты римановых многообразий – равномерность структуры – выглядят перспективными, поскольку реализуются хотя бы на одном достаточно широком классе поверхностей в гильбертовом пространстве. Целесообразной выглядит разработка подходов к рассмотрению краевых задач на таких бесконечномерных римановых многообразиях

Linguistic rhetoric of Soviet discourse: official vs personal register (J. Stalin – A. Dovzhenko)

Within the conception of the Sochi Linguistic & Rhetorical School the paper discusses the diglossia of the Soviet discourse employed in the former USSR, distinguishes official and personal registers as well as shows their difference drawing on Joseph Stalin’s speech of 31 January 1944 to the Politburo of the Central Committee of the All-Union Communist Party of Bolsheviks concerning Alexander Dovzhenko’s screenplay “Ukraine in Flames” and in the writer’s diaries. The comparison reveals a few specific linguistic rhetorical features of cognitive communicative type ontologically characteristic of the Soviet linguistic personality’s communicative cognitive activity in a totalitarian state. The cognitive features of Stalin’s individual discourse representing the official register and his system of argumentation rest on the significative component of linguistic units, arguments from literature to illustrate the postulates and dogmas of Marxist-Leninist doctrine forming the foundation of the Soviet discourse. It is also found that the official register represented by Stalin’s speech is characterized by the following features: 1) repetition; 2) sarcastic remarks; 3) dramatic mutually exclusive contrast of mental spaces (“our own, true in the last resort” and destructed, represented by the opponent’s discourse); 4) rigidly adversarial characteristic of the alternative linguistic rhetorical worldview; 5) appeal to the Soviet collective linguistic personality’s opinion; 6) ideological translation from one subdiscourse into the other, from personal register into the official one; 7) biased retelling of the discourse regarded as anti-Soviet; 8) appeal to the facts lacking in the discourse under criticism; 9) “ideological editing” taking on the form of peremptory lecturing with consequences threatening the liberty of the person under criticism. The personal register of the Soviet Ukrainian writer Dovzhenko is characterized by a broad interpretation of reality devoid of the “Marxist-Leninist blinds” and a more objective interpretation of the world due to a bigger ratio of denotative references (“evidential arguments” like “I say” and “I heard” etc) and communicative cognitive activity relative to two axiological hierarchies: national and Christian, i.e. the dominance of human values over class morality. It is proved that Dovzhenko’s screenplay was criticized within Stalin’s official register for its deviation from the cognitive schemas and the model of the Soviet discourse, for the focus on Ukraine and its citizens rather than on class struggle

SYNTHESIS AND STUDY OF SULFIDE CATALYSTS FOR PHOTOCATALYTIC HYDROGEN PRODUCTION

A series of novel catalysts Cd0.4Mn0.6S/g-C3N4 with different Cd0.4Mn0.6S contents was synthesized. The obtained composites showed high photocatalytic activities in H2 evolution reaction and the highest H2 evolution rate of 0.23 μmol min−1.This work was supported by the grant of the President of the Russian Federation MD-79.2020.3

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

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