1,493 research outputs found

    The efficiency coefficient of the rat heart and muscular system after physical training and hypokinesia

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    The efficiency of an isolated heart did not change after prolonged physical training of rats for an extreme load. The increase in oxygen consumption by the entire organism in 'uphill' running as compared to the resting level in the trained rats was 14% lower than in the control animals. Prolonged hypokinesia of the rats did not elicit a change in the efficiency of the isolated heart

    New records of lichens from the Russian Far East. I. Fuscidea submollis and other arctic-alpine species

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    Summary. Fuscidea submollis Mas. Inoue is reported for the first time from the Russian Far East. Distinctive features of the taxon are discussed, and a comparison with known saxicolous Fuscidea V. Wirth & Vězda species with amyloid medulla is made. Three arctic-alpine species: Sporastatia testudinea (Ach.) A. Massal., Buellia concinna Th. Fr., Amygdalaria panaeola (Ach.) Hertel et Brodo, and Aspilidea myrinii (Fr.) Hafellner are recorded for the first time in the South Far East from the Sikhote Alin Range (Primorye Territory). Calvitimela aglaea (Sommerf.) Hafellner is reported for the first time from Sikhote Alin Range and Primorye Territory. © 2019 Altai State University. All rights reserved.Japan Society for the Promotion of Science, JSPS: 19-54-50010Russian Foundation for Basic Research, RFBRThe reported study was funded by RFBR and JSPS according to the research project № 19-54-50010

    Triaxial projected shell model approach

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    The projected shell model analysis is carried out using the triaxial Nilsson+BCS basis. It is demonstrated that, for an accurate description of the moments of inertia in the transitional region, it is necessary to take the triaxiality into account and perform the three-dimensional angular-momentum projection from the triaxial Nilsson+BCS intrinsic wavefunction.Comment: 9 pages, 2 figure

    Nonlinearity-induced conformational instability and dynamics of biopolymers

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    We propose a simple phenomenological model for describing the conformational dynamics of biopolymers via the nonlinearity-induced buckling and collapse (i.e. coiling up) instabilities. Taking into account the coupling between the internal and mechanical degrees of freedom of a semiflexible biopolymer chain, we show that self-trapped internal excitations (such as amide-I vibrations in proteins, base-pair vibrations in DNA, or polarons in proteins) may produce the buckling and collapse instabilities of an initially straight chain. These instabilities remain latent in a straight infinitely long chain, because the bending of such a chain would require an infinite energy. However, they manifest themselves as soon as we consider more realistic cases and take into account a finite length of the chain. In this case the nonlinear localized modes may act as drivers giving impetus to the conformational dynamics of biopolymers. The buckling instability is responsible, in particular, for the large-amplitude localized bending waves which accompany the nonlinear modes propagating along the chain. In the case of the collapse instability, the chain folds into a compact three-dimensional coil. The viscous damping of the aqueous environment only slows down the folding of the chain, but does not stop it even for a large damping. We find that these effects are only weakly affected by the peculiarities of the interaction potentials, and thus they should be generic for different models of semiflexible chains carrying nonlinear localized excitations.Comment: 4 pages (RevTeX) with 5 figures (EPS

    Triaxial deformation in 10Be

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    The triaxial deformation in 10^{10}Be is investigated using a microscopic α+α+n+n\alpha+\alpha+n+n model. The states of two valence neutrons are classified based on the molecular-orbit (MO) model, and the π\pi-orbit is introduced about the axis connecting the two α\alpha-clusters for the description of the rotational bands. There appear two rotational bands comprised mainly of Kπ=0+K^\pi = 0^+ and Kπ=2+K^\pi = 2^+, respectively, at low excitation energy, where the two valence neutrons occupy Kπ=3/2−K^\pi = 3/2^- or Kπ=1/2−K^\pi = 1/2^- orbits. The triaxiality and the KK-mixing are discussed in connection to the molecular structure, particularly, to the spin-orbit splitting. The extent of the triaxial deformation is evaluated in terms of the electro-magnetic transition matrix elements (Davydov-Filippov model, Q-invariant model), and density distribution in the intrinsic frame. The obtained values turned out to be Îł=15o∌20o\gamma = 15^o \sim 20^o.Comment: 15 pages, latex, 3 figure

    ON THE SPECIFIC FEATURES OF SILICON CARBIDE HETEROPOLYTYPE EPITAXY

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    Specific features of silicon carbide layer formation with the structure (polytype) different from the SiC-substrate structure (polytype) are considered. Simple theoretical foundations of the nonstoichiometric character, impurities, C- and Si-faces effect on the heteropolytype epitaxy (HPE) of silicon carbide are proposed. By means of Harrison’s bond orbital model it is shown that the adsorption possibility for the C-face is much greater than for the Si-face. Within the scopes of the earlier proposed models (D-model and vacancy model) it is demonstrated that the presence of impurities changes characteristic lifetimes of the HPE process and the transition layer widths: impurities which enforce the interpolytype transition decrease corresponding life-time constants and the transition layer widths. For interpretation of the polytype stripes existence within the transition layer, the model of specific spinodal decomposition taking into account vacancy concentrations variations in both SiC sublattices is used

    Quantum Electrodynamics and the Origins of the Exchange, Dipole-Dipole, and Dzyaloshinsky-Moriya Interactions in Itinerant Fermion Systems

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    It is shown how the exchange interaction, the dipole-dipole interaction, and the Dzyaloshinsky-Moriya interaction between electronic spin-density fluctuations emerge naturally from a field-theoretic framework that couples electrons to the fluctuating electromagnetic potential. Semi-quantitative estimates are given to determine when the dipole-dipole interaction, which is often neglected, needs to be considered, and various applications are discussed, with an emphasis on weak ferromagnets and on helimagnets.Comment: 12pp, 3 fig

    Relativistic quantum mechanics of a Dirac oscillator

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    The Dirac oscillator is an exactly soluble model recently introduced in the context of many particle models in relativistic quantum mechanics. The model has been also considered as an interaction term for modelling quark confinement in quantum chromodynamics. These considerations should be enough for demonstrating that the Dirac oscillator can be an excellent example in relativistic quantum mechanics. In this paper we offer a solution to the problem and discuss some of its properties. We also discuss a physical picture for the Dirac oscillator's non-standard interaction, showing how it arises on describing the behaviour of a neutral particle carrying an anomalous magnetic moment and moving inside an uniformly charged sphere.Comment: 19 pages, 1 figur

    GIANT OPTICAL NONLINEARITY OF HETEROSTRUCTURES WITH InP SELF-ASSEMBLED QUANTUM DOTS

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    A nonlinear reection of the heterostructures with InP self-assembled quantumdots is studied by pump-probe technique. A saturation of pump-probe signal inthe spectral region of the absorption of quantum dots is found at extremely lowpump power density of about 1 W/cm2. This value together with estimation ofthe absorption coefficient leads to the conclusion that saturation of the nonlinearreection occurs when quantum dot absorbs only single quantum of the light. Thisis a real evidence of the giant optical nonlinearity of the quantum dots.24th International Conference on the Physics of Semiconductors : Jerusalem, Israel August 2-7, 199
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