725 research outputs found

    Transition state method and Wannier functions

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    We propose a computational scheme for materials where standard Local Density Approximation (LDA) fails to produce a satisfactory description of excitation energies. The method uses Slater's "transition state" approximation and Wannier functions basis set. We define a correction to LDA functional in such a way that its variation produces one-electron energies for Wannier functions equal to the energies obtained in "transition state" constrained LDA calculations. In the result eigenvalues of the proposed functional could be interpreted as excitation energies of the system under consideration. The method was applied to MgO, Si, NiO and BaBiO3_3 and gave an improved agreement with experimental data of energy gap values comparing with LDA.Comment: 13 pages, 6 figures, 1 tabl

    Polarized neutron channeling as a tool for the investigations of weakly magnetic thin films

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    We present and apply a new method to measure directly weak magnetization in thin films. The polarization of a neutron beam channeling through a thin film structure is measured after exiting the structure edge as a microbeam. We have applied the method to a tri-layer thin film structure acting as a planar waveguide for polarized neutrons. The middle guiding layer is a rare earth based ferrimagnetic material TbCo5 with a low magnetization of about 20 mT. We demonstrate that the channeling method is more sensitive than the specular neutron reflection method

    Spin state of negative charge-transfer material SrCoO3

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    We employ the combination of the density functional and the dynamical mean-field theory (LDA+DMFT) to investigate the electronic structure and magnetic properties of SrCoO3, monocrystal of which were prepared recently. Our calculations lead to a ferromagnetic metal in agreement with experiment. We find that, contrary to some suggestions, the local moment in SrCoO3 does not arise from intermediate spin state, but is a result of coherent superposition of many different atomic states. We discuss how attribution of magnetic response to different atomic states in solids with local moments can be quantified.Comment: 5 pages, 5 figure

    Imitation forecast of railway system operation in a macroregion

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    The article describes an analytical and information system that was used for forecasting the operation parameters of the railway system in a macroregion of Russia - the Far North. Its economy is focused on the extraction and processing of hydrocarbons, metal production, construction materials, and generate large volumes of exports and inter-regional cargo flows. The region covers an expansive territory and is characterized by harsh weather, an extreme environment, and uneven development of the transportation network. Research into the transportation issues of economic development in such areas presents a challenging task because the region is unique, statistical data are incomplete and classified; there is a hierarchy of businesses and organizations operating in the region that have their own goals and objectives and compete against its other; the region is plagued with social and environmental problems and a lack of administrative integration between individual districts. Using rigorous mathematical tools for assessing transportation infrastructure projects under such conditions is only limited to finding solutions to stand-alone problems and scenario comparison. A model of the applied system that is outlined in the article makes it possible to analyze specific projects of regional railway system development that take into account strategic priorities and goals of the state, social and economic development problems experienced by the neighboring regions, the oil and gas sector and major employers, as well as corporate goals of the sustainable development of railway companies. The application of the model over an extended period of time showed that the analysis of the structure of cargo flows and customers bound to junctions of the transportation network makes it possible to suggest what aspects of the railway infrastructure should be reorganized in line with the development dynamics of economic entities that consume transportation services. The study is built upon a number of projects that were implemented in the north of Tyumen Region and the Yamal- Nenets and Khanty-Mansi autonomous areas of Russia. © 2018 WIT Press.ACKNOWLEDGEMENT The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006

    Information and simulation model for complex regional transport

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    The main difficulties related to the economic study of traffic problems are caused by the large number of interrelated factors, hierarchical and competing goals of economic subjects, social and environmental problems of the territory, the degree of administrative independence of its individual parts, as well as the importance of regional economy within the country. The application of rigorous mathematical tools to assess trends in the development of transport infrastructure in these conditions is very limited and is usually reduced to the justification of a few scenarios. The paper offers specific methodological approaches, analytical apparatus with a number of the analyzed conditions and factors, a logical basis for the formation of scenarios in the design of transport systems, including the railway infrastructure of the region. The novelty of the approach used is a combination of accounting features of the territory from the perspective of mineral resources development, and quantification of long-term needs in the freight made on the balance calculations basis. © 2015 WIT Press

    EFFECT OF IMMUNOTHERAPY ACTIVATED T-LYMPHOCYTES ON CELLULAR IMMUNITY IN DIFFERENT FORMS OF ATOPIC DERMATITIS

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    The article describes the results of therapy with autologous activated. T-lymphocytes in patients with atopic dermatitis. Has been shown high clinical efficacy and safety of this therapy in the treatment of patients with both allergic and nonallergic form of the disease. In the allergic form observed more rapid positive changes, but in the opposite form of the efficiency was higher. Influence on cellular immunity in different forms differed. If the allergic form there was an increase of CD8+ T-cells in the nonallergic form — increased CD8+CD25+ T-cells and changes in delayed-type hypersensitivity
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