2,032 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

    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=3/2K^\pi = 3/2^- or Kπ=1/2K^\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 γ=15o20o\gamma = 15^o \sim 20^o.Comment: 15 pages, latex, 3 figure

    Observation of built-in electric field in InP self-assembled quantum dot systems

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    Strong Franz–Keldysh oscillations were observed in the nonlinear reflection spectra ofheterostructures with InP self-assembled quantum dots. These oscillations manifest a built-inelectric field of about 30 kV/cm. We propose that this field originates from electric charge capturedby the intrinsic defects on the dot interface. The presence of acceptor-like intrinsic defect states isfound to be a general feature of the InP/InGaP interface but was not observed in other structureswith quantum dots such as InAs/GaAs

    Stabilization of high-order solutions of the cubic Nonlinear Schrodinger Equation

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    In this paper we consider the stabilization of non-fundamental unstable stationary solutions of the cubic nonlinear Schrodinger equation. Specifically we study the stabilization of radially symmetric solutions with nodes and asymmetric complex stationary solutions. For the first ones we find partial stabilization similar to that recently found for vortex solutions while for the later ones stabilization does not seem possible

    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 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

    Structure and Stability of Two-Dimensional Complexes of C_20 Fullerenes

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    Two-dimensional complexes of C_20 fullerenes connected to each other by covalent bonds have been studied. Several isomers with different types of intercluster bonds have been revealed. The lifetimes of the (C_20)_MxM systems with M = 2 and 3 have been directly calculated at T = 1800 - 3300 K making use of molecular dynamics. It has been shown that these complexes lose their periodic cluster structure due to either coalescence of two fullerenes C_20 or decay of C_20 fullerenes. The activation energies of these processes exceed 2 eV.Comment: 17 pages, 5 figure
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