7,512 research outputs found

    Modeling of "groove" rolling defect on internal surface of pipes at lengthwise rolling

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    The research has been conducted in pipe forming at rolling off by lengthwise rolling mill with stub mandrel; the patterns of change in dimensionless parameters were determined, which characterize deformation in side angle depending on http://www.multitran.ru/c/m.exe?t=424995_2_1elongation ratio. The model of formation of lengthwise groove on internal surface of pipes has been proposed

    Electronic structure of FeSe monolayer superconductors

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    We review a variety of theoretical and experimental results concerning electronic band structure of superconducting materials based on FeSe monolayers. Three type of systems are analyzed: intercalated FeSe systems A_xFe_2Se_{2-x}S_x and [Li_{1-x}Fe_xOH]FeSe as well as the single FeSe layer films on SrTiO_3 substrate. We present the results of detailed first principle electronic band structure calculations for these systems together with comparison with some experimental ARPES data. The electronic structure of these systems is rather different from that of typical FeAs superconductors, which is quite significant for possible microscopic mechanism of superconductivity. This is reflected in the absence of hole pockets of the Fermi surface at \Gamma-point in Brillouin zone, so that there are no "nesting" properties of different Fermi surface pockets. LDA+DMFT calculations show that correlation effects on Fe-3d states in the single FeSe layer are not that strong as in most of FeAs systems. As a result, at present there is no theoretical understanding of the formation of rather "shallow" electronic bands at M points. LDA calculations show that the main difference in electronic structure of FeSe monolayer on SrTiO_3 substrate from isolated FeSe layer is the presence of the band of O-2p surface states of TiO_2 layer on the Fermi level together with Fe-3d states, which may be important for understanding the enhanced T_c values in this system. We briefly discuss the implications of our results for microscopic models of superconductivity.Comment: 21 pages, 13 figures, minor typos correcte

    Space-Time Description of Scalar Particle Creation by a Homogeneous Isotropic Gravitational Field

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    We give the generalization of the method of the space-time description of particle creation by a gravitational field for a scalar field with nonconformal coupling to the curvature. The space-time correlation function is obtained for a created pair of the quasi-particles, corresponding to a diagonal form of the instantaneous Hamiltonian. The case of an adiabatic change of the metric of homogeneous isotropic space is analyzed. We show that the created pairs of quasi-particles in de Sitter space should be interpreted as pairs of virtual particles.Comment: 7 pages, 3 figure

    THERAPEUTIC EFFECT OF MILGAMMA N IN SYMPTOMATIC NEURALGIA IN THE COURSE AND AFTER HERPES ZOSTER GANGLIONITIS

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    Herpes zoster is a dermatovirosis that occurs at different age. However, with the patients aged over 60 years it presents with a painful syndrome preceded, accompanied or lasting up to one year after fading away of the eruptions. Intake of B-group vitamins favourably influences on the restoration of sensory nerves being mainly affected and causing the protracted painful syndrome. Milgamma N preparation in the shape of capsules is a combination of 40mg of vit. Bi, of 90mg of vit. Вб, and of 250 у of vit. Bn and ensures an optimal intestinal resorption. The authors followed-up dynamically the therapeutic effect of Milgamma N in capsules on the development of skin lesions and painful syndrome in 15 patients (7 males and 8 females) with herpes zoster. The duration of the therapy was 4 weeks long. The following protocol was made use of: week one - two capsules three times daily and weeks two through four - three times one capsule daily. The dermatologic and neurologic status as well as the subjective evaluation of the therapeutic effect was monitored in all the patients. There was a complete or an almost complete remission in 13 patients (86,7% of the cases) after one-month treatment. The skin lesions underwent an involution during a period of 10-17 days. The one-month schedule for treatment of herpes zoster with Milgamma N proved to be effective in a moderate degree of a painful syndrome and most common localization of the eruptions

    Photon assisted tunneling in pairs of silicon donors

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    Shallow donors in silicon are favorable candidates for the implementation of solid-state quantum computer architectures because of the promising combination of atomiclike coherence properties and scalability from the semiconductor manufacturing industry. Quantum processing schemes require (among other things) controlled information transfer for readout. Here we demonstrate controlled electron tunneling at 10 K from P to Sb impurities and vice versa with the assistance of resonant terahertz photons
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