61 research outputs found
Retrieval of Effective Parameters of Subwavelength Periodic Photonic Structures
We revisit the standard Nicolson–Ross–Weir method of effective permittivity and permeability restoration of photonic structures for the case of subwavelength metal-dielectric multilayers. We show that the direct application of the standard method yields a false zero-epsilon point and an associated spurious permeability resonance. We show how this artifact can be worked around by the use of the cycle shift operator to the periodic multilayer in question
Molecular dynamics simulation of the effect of dislocations on the martensitic transformations in a two-dimensional model
Investigation of the thermoelastic martensitic transformation is of high interest nowadays because of the numerous applications of the materials with such structural peculiarities. Thermodynamics, kinetics, structure, morphology of martensitic transformation still remain unclear in many respects. From this point of view, the effective way to study various properties of metallic crystals on atomistic level is molecular dynamics simulation, for which good qualitative agreement with the experiment can be achieved even with simple Morse or Lennard-Jones interatomic potentials. In this paper, the effect of dislocations on the direct and reverse martensitic transformation is studied by molecular dynamics simulation in a two-dimensional model of the ordered alloy with the AB stoichiometry. The three dimensional analog to this structure is B2 superstructure based on bcc lattice, which is characteristic for intermetallic NiTi alloy. It is found, that the dislocations can be considered as the nucleation centers for martensite phase, increasing the temperature of the direct martensitic transformation in comparison with the homogeneous martensitic transformation. The martensite domains found in the structure after transformation and the reverse martensitic transformation takes place in the presence of the domain boundaries, meaning that the austenite nucleates heterogeneously. At the reverse transformation, splitting of perfect dislocations into partials dislocations took place. Thus, it was established in the present study that, on the one hand, dislocations affect the direct martensitic transformation as the nucleation centers, and from the other hand, reverse martensitic transformation changes the dislocation structure of the modeled alloy. © 2017, Institute for Metals Superplasticity Problems of Russian Academy of Sciences. All rights reserved.MD simulation of direct and reverse MT in the framework of the 2D model of an ordered alloy shows that dislocations can be considered as the nucleation centers of martensite during direct MT. In the absence of dislocations, martensite nucleates homogeneously at lower temperatures. The reverse MT occurs in the presence of twinned martensite and domain walls in the system, which means that even in the absence of dislocations, the structure of the alloy is not ideal. During the reverse MT, the perfect dislocations split into partial dislocations. It should be noted that for selected model parameters MT is associated with large lattices deformations, therefore, temperature hysteresis is also large, which is not typical for SM alloys. However, the consideration of the Acta Mater. 95, 37 (2015). effects of SM and superelasticity is not prohibited in frame of 14. C. Ni, H. Ding, XJ.. Jin. J. Alloys Compd. 546, 1 (2013). this model, since the degree of coherence of the martensite 15. S. Kazanc, FA. . Celik, S. Ozgen. J. Phys. Chem. Solids. 74, and austenite lattices is quite high. One of the important 1836 (2013). problems for futher investigations is the studying of the MT 16. T. Suzuki, M. Shimno, K. Otsuka, X. Ren, A. Saxena. as the detonation process [36]. J. Alloys Compd. 577S, S113 (2013). 17. B. Wang, E. Sak-Saracino, N. Gunkelmann, Aknowledgements. S.V. D. acknowledges support from the H.M. Urbassek. Comp. Mater. Sci. 82, 399 (2014). Russian Foundation for Basic Research, grant No. 16-58-48001 18. C. Tatar, S. Kazanc. Current Applied Physics. 12, 98 IND_omi (design of the research, discussion of the results). (2012). J.A. B and V.G. P. are grateful for the financial support from 19. A.R. Kuznetsov, Yu.N. Gornostyrev, M.I. Katsnelson, the Russian Science Foundation, grant No. 15-12-10014 A. V. Trefilov. Mater. Sci Eng. A309–311068 (2001). (numerical simulations and writing the paper). R.I. B. thanks 20. I.N. Kar’kin, Yu.N. Gornostyrev, L.E. Kar’kina. Phys. financial support from the Russian Science Foundation, grant Solid State. 52, 431 (2010). No. 17-79-10410 (numerical simulations). The work of D. V. G. 21. Y. N. Gornostyrev, IN. . Kar’kin, LE. . Kar’kina. Phys. Solid was supported by the Saint-Petersburg State University, State. 53, 1388 (2011). research grant No. 6.65.43.2017 (discussion of the results). 22. J.A. Baimova, R.I. Babicheva, A.V. Lukyanov, V.G. Pushin
RISK OF RENEWABLE ENERGY SOURCES DEVELOPMENT IN THE OIL AND GAS INDUSTRY IN THE CONTEXT OF COVID-19
The global climate problem of climate warming has led to the active development of renewable energy almost all over the world. Many European countries and international corporations are already striving for carbon neutrality.This article analyzes the current trends in the development of the renewable energy sources industry in the world and in Russia, assesses the applicability of renewable energy sources in the oil and gas industry and the impact of the coronavirus crisis on the perspectives for renewable energy. The analysis of the indicators of the volumes of commissioning of generating capacities for 2020 is given, the obstacles encountered in the development of the industry due to the unstable global situation are considered.The article also discusses investment in renewable energy by oil and gas companies and their transformation under the influence of the renewable energy sector, as well as the participation of Russian companies in this transformation and their long-term prospects in relation to renewable energy
DEVELOPING MICROGENERATION BASED ON RES AS A DRIVER OF DECARBONISATION AND ECONOMIC GROWTH IN RUSSIA
Having analysed the domestic and foreign experience of developing the market of microgeneration based on renewable energy sources (RES) the authors conclude that a smart industrial policy can ensure an expedited transition to zero-carbon economy and stimulate economic growth. Research background – Russia’s commitment to achieve carbon neutrality by 2060. Research purpose – assessing the prospects and barriers in the development of microgeneration based on RES. Methods – generalising, comparing, analysing empirical evidence of microgeneration market development in Russia and abroad, calculating the levelized cost of electricity (LCOE) of a solar plant and comparing it with current low voltage tariffs for small and medium-sized businesses. Results and novelty – the authors have determined the most effective industrial policy tools for developing the market of microgeneration based on RES
Methods of thrombus age determination
Relevance: Venous thromboembolic complications are a formidable condition with a high mortality risk, that is rather common in the practice of a physician of any specialty. Therefore, timely diagnosis and correct management of patients with thromboembolic complications are key to a favorable outcome of the disease. An urgent problem for science nowadays is the search and development of diagnostic approaches that give a complete description of a thrombotic event. One of these characteristics is the determination of the age of thrombosis; it is a clear understanding of this criterion that makes it possible to choose a successful treatment strategy for patients with similar complications.Aim of study: To date, the assessment of the age of a thrombus is based mainly on the patient’s anamnestic data, which do not always correspond to the real situation, and imaging techniques based on indirect signs. Therefore, the ineffectiveness of therapy for the described conditions in some cases can be explained by an underestimation of the age of the thrombus. The development of scientific research in this direction seems promising and can lead to an improvement in the results of treatment of patients suffering from venous thromboembolic complications. This article is a review of the methods for thrombus age determination presented in the literature
РИСКИ РАЗВИТИЯ ВИЭ В НЕФТЕГАЗОВОЙ ОТРАСЛИ В УСЛОВИЯХ COVID-19
The global climate problem of climate warming has led to the active development of renewable energy almost all over the world. Many European countries and international corporations are already striving for carbon neutrality.This article analyzes the current trends in the development of the renewable energy sources industry in the world and in Russia, assesses the applicability of renewable energy sources in the oil and gas industry and the impact of the coronavirus crisis on the perspectives for renewable energy. The analysis of the indicators of the volumes of commissioning of generating capacities for 2020 is given, the obstacles encountered in the development of the industry due to the unstable global situation are considered.The article also discusses investment in renewable energy by oil and gas companies and their transformation under the influence of the renewable energy sector, as well as the participation of Russian companies in this transformation and their long-term prospects in relation to renewable energy.Глобальная проблема изменения климата привела к активному развитию возобновляемой энергетики практически по всему миру. Множество европейских стран и международных корпораций уже сегодня стремятся к углеродной нейтральности.В настоящей статье проанализированы сложившиеся тенденции развития отрасли возобновляемых источников энергии в мире и в России, оценены применимость ВИЭ в нефтегазовой отрасли и влияние коронакризиса на перспективы возобновляемой энергетики. Приведен анализ показателей объемов ввода генерирующих мощностей за 2020 год, описаны возникшие препятствия в развитии отрасли в связи с нестабильным характером мировой ситуации.Также в статье рассмотрены особенности инвестирования в ВИЭ со стороны нефтегазовых компаний и их трансформация под влиянием сектора возобновляемых источников энергии, а также участие российских компаний в этой трансформации
РАЗВИТИЕ МИКРОГЕНЕРАЦИИ НА ОСНОВЕ ВИЭ КАК ФАКТОР ДЕКАРБОНИЗАЦИИ И ЭКОНОМИЧЕСКОГО РОСТА В РОССИИ
Having analysed the domestic and foreign experience of developing the market of microgeneration based on renewable energy sources (RES) the authors conclude that a smart industrial policy can ensure an expedited transition to zero-carbon economy and stimulate economic growth. Research background – Russia’s commitment to achieve carbon neutrality by 2060. Research purpose – assessing the prospects and barriers in the development of microgeneration based on RES. Methods – generalising, comparing, analysing empirical evidence of microgeneration market development in Russia and abroad, calculating the levelized cost of electricity (LCOE) of a solar plant and comparing it with current low voltage tariffs for small and medium-sized businesses. Results and novelty – the authors have determined the most effective industrial policy tools for developing the market of microgeneration based on RES.Базируясь на анализе отечественного и зарубежного опыта развития рынка микрогенерации на основе возобновляемых источников энергии (ВИЭ), авторы приходят к выводу, что за счет реализации продуманной промышленной политики возможно обеспечить ускоренный переход к безуглеродной экономике и стимулировать экономический рост. Предпосылки исследования – обязательства России по достижению углеродной нейтральности к 2060 году. Цель исследования – оценить перспективы и барьеры, сдерживающие развитие возобновляемой микрогенерации на основе ВИЭ.В статье были использованы обобщение, сравнение, анализ эмпирических данных развития рынка микрогенерации в России и за рубежом, сделан расчет стоимости солнечной электростанции и проведено сравнение с существующими тарифами на низком напряжении для малого и среднего бизнеса. Определены наиболее действенные инструменты промышленной политики в области развития рынка микрогенерации на основе ВИЭ
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