21,244 research outputs found

    The history of constructivism in the Urals: 21st-century studies

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    The article was submitted on 28.07.2016.Статья посвящена научному обзору и анализу трудов современных исследователей по истории архитектуры конструктивизма на Урале. Наличие в крупных и малых городах Урала различных экспериментальных градостроительных решений и приемов квартальной застройки, типологического разнообразия общественных, жилых, производственных зданий и сооружений, реализованных в стилистических формах конструктивизма, существенно выделяет Уральский регион от других районов страны. По решению ЦИК СССР в 1923 г. была создана Уральская область с целью увеличения промышленно-хозяйственного потенциала страны, и попутно с целью решения основных проблем реконструкции «культуры и быта». Внедрение современных строительных материалов и конструкций, новаторские поиски в архитектуре объемно-пространственных решений, различных по типологии объектов в рациональной стилистике широко использовалось в застройке таких городов как Пермь, Челябинск, Магнитогорск, Курган, Нижний Тагил, Свердловск, Златоуст, Надеждинск и др. Социальная и художественная направленность современного по тем годам творческого течения повлияла на формирование новой структуры уральских городов, преобразовала архитектурный язык и облик построек, позволила создать новые, ранее не встречающиеся в архитектурной практике типы зданий, изменила представление людей об удобстве, стиле и качестве жизни. С середины 1930-х до начала 1990-х гг. многие уральские города решением правительства страны были закрыты для зарубежных исследователей советской авангардной архитектуры, а на публикации книг и статей об объектах конструктивизма в стране было наложено табу. Поэтому одни из первых серьезных публикаций конструктивистских объектов, сооруженных в уральских городах, появились только на рубеже ХХ–ХХΙ вв. С начала нового века стала складываться научная школа истории уральской авангардной архитектуры, известными представителями которой являются А. А. Барабанов, Е. В. Конышева, Л. Н. Смирнов, А. А. Стариков, Л. И. Токменинова, Л. П. Холодова и другие ученые.The article features a comprehensive review of recent research on the history of Constructivism in the Urals. Various experimental urban solutions in Ural cities and towns, innovative models of quarter planning, and the typological diversity of public, residential, and industrial buildings built in Constructivist style makes Ural region distinct from other parts of the country. The introduction of contemporary building materials and designs and novel research into the usage of space can be seen in diverse buildings in Perm, Chelyabinsk, Magnitogorsk, Kurgan, Nizhny Tagil, Sverdlovsk, Zlatoust, Nadezhdinsk, and others. The social and artistic direction of Constructivism as an ultra-modern creative movement greatly influenced the new architectural look of cities in the Urals. It also transformed the language of architecture and the visual imagery of buildings: it allowed for the creation of new, unprecedented architectural types and changed people’s ideas about convenience, style, and quality of life. From the mid-1930s until the early 1990s, many towns in the Urals were closed off to foreign researchers: the publication of books and articles about Constructivism was also prohibited. This is why the first serious publications about the Constructivist heritage of the Urals appeared only at the beginning of the 21st century. Thus began a rise in scholarship on this subject

    Optically induced spin polarization of an electric current through a quantum dot

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    We examine electron transport through semiconductor quantum dot subject to a continuous circularly polarized optical irradiation resonant to the electron - heavy hole transition. Electrons having certain spin polarization experience Rabi oscillation and their energy levels are shifted by the Rabi frequency. Correspondingly, the equilibrium chemical potential of the leads and the lead-to-lead bias voltage can be adjusted so only electrons with spin-up polarization or only electrons with spin-down polarization contribute to the current. The temperature dependence of the spin polarization of the current is also discussed.Comment: Several misprints are correcte

    Atmospheric neutrinos: LMA oscillations, Ue3 induced interference and CP-violation

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    We consider oscillations of the low energy (sub-GeV sample) atmospheric neutrinos in the three neutrino context. We present the semi-analytic study of the neutrino evolution and calculate characteristics of the e-like events (total number, energy spectra and zenith angle distributions) in the presence of oscillations. At low energies there are three different contributions to the number of events: the LMA contribution (from electron-neutrino oscillations driven by the solar oscillation parameters), the Ue3-contribution proportional to s13**2, and the Ue3 - induced interference of the two amplitudes driven by the solar oscillation parameters. The interference term is sensitive to the CP-violation phase. We describe in details properties of these contributions. We find that the LMA, the interference and Ue3 contributions can reach 5 - 6%, 2 - 3% and 1 - 2 % correspondingly. An existence of the significant (> 3 - 5 %) excess of the e-like events in the sub-GeV sample and the absence of the excess in the multi-GeV range testifies for deviation of the 2-3 mixing from maximum. We consider a possibility to measure the deviation as well as the CP- violation phase in future atmospheric neutrino studies.Comment: 30 pages, RevTeX4.0, 11 figures; improved figure

    Optimized Neural Networks to Search for Higgs Boson Production at the Tevatron

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    An optimal choice of proper kinematical variables is one of the main steps in using neural networks (NN) in high energy physics. Our method of the variable selection is based on the analysis of a structure of Feynman diagrams (singularities and spin correlations) contributing to the signal and background processes. An application of this method to the Higgs boson search at the Tevatron leads to an improvement in the NN efficiency by a factor of 1.5-2 in comparison to previous NN studies.Comment: 4 pages, 4 figures, partially presented in proceedings of ACAT'02 conferenc
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