6,588 research outputs found

    Nonlocality of nucleon interaction and an anomalous off shell behavior of the two-nucleon amplitudes

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    The problem of the ultraviolet divergences that arise in describing the nucleon dynamics at low energies is considered. By using the example of an exactly solvable model it is shown that after renormalization the interaction generating nucleon dynamics is nonlocal in time. Effects of such nonlocality on low-energy nucleon dynamics are investigated. It is shown that nonlocality in time of nucleon-nucleon interactions gives rise to an anomalous off-shell behavior of the two-nucleon amplitudes that have significant effects on the dynamics of many-nucleon systems.Comment: 9 pages, 4 figures, ReVTeX

    On the total mean curvature of non-rigid surfaces

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    Using Green's theorem we reduce the variation of the total mean curvature of a smooth surface in the Euclidean 3-space to a line integral of a special vector field and obtain the following well-known theorem as an immediate consequence: the total mean curvature of a closed smooth surface in the Euclidean 3-space is stationary under an infinitesimal flex.Comment: 4 page

    Wave packet dynamics and valley filter in strained graphene

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    The time evolution of a wavepacket in strained graphene is studied within the tight-binding model and continuum model. The effect of an external magnetic field, as well as a strain-induced pseudo-magnetic field, on the wave packet trajectories and zitterbewegung are analyzed. Combining the effects of strain with those of an external magnetic field produces an effective magnetic field which is large in one of the Dirac cones, but can be practically zero in the other. We construct an efficient valley filter, where for a propagating incoming wave packet consisting of momenta around the K and K' Dirac points, the outgoing wave packet exhibits momenta in only one of these Dirac points, while the components of the packet that belong to the other Dirac point are reflected due to the Lorentz force. We also found that the zitterbewegung is permanent in time in the presence of either external or strain-induced magnetic fields, but when both the external and strain-induced magnetic fields are present, the zitterbewegung is transient in one of the Dirac cones, whereas in the other cone the wave packet exhibits permanent spatial oscillations.Comment: 13 pages, 10 figure

    Generalized Neighbor-Interaction Models Induced by Nonlinear Lattices

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    It is shown that the tight-binding approximation of the nonlinear Schr\"odinger equation with a periodic linear potential and periodic in space nonlinearity coefficient gives rise to a number of nonlinear lattices with complex, both linear and nonlinear, neighbor interactions. The obtained lattices present non-standard possibilities, among which we mention a quasi-linear regime, where the pulse dynamics obeys essentially the linear Schr{\"o}dinger equation. We analyze the properties of such models both in connection with their modulational stability, as well as in regard to the existence and stability of their localized solitary wave solutions

    On compression of Bruhat-Tits buildings

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    We obtain an analog of the compression of angles theorem in symmetric spaces for Bruhat--Tits buildings of the type AA. More precisely, consider a pp-adic linear space VV and the set Lat(V)Lat(V) of all lattices in VV. The complex distance in Lat(V)Lat(V) is a complete system of invariants of a pair of points of Lat(V)Lat(V) under the action of the complete linear group. An element of a Nazarov semigroup is a lattice in the duplicated linear space VVV\oplus V. We investigate behavior of the complex distance under the action of the Nazarov semigroup on the set Lat(V)Lat(V).Comment: 6 page

    Studies of kinetics and thermodynamic parameters of cashmere dyeing with bio-preparation of Urtica Cannabina L,

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    In this study, dyeing Mongolian cashmere with bio-preparation extracted from Urtica cannabina L. was investigated. Dyeing experiments were carried out under varying pH, temperature and contact time. The results have been used to investigate the kinetic and thermodynamic parameters of dyeing cashmere. This process is pH dependent and it has been found that the most suitable condition is pH 4.5. Increase in adsorption capacity with increase in temperature indicates that the dyeing process is endothermic. Thermodynamic parameters like standard affinity (∆µ), standard enthalpy (∆H) and standard entropy (∆S) were evaluated

    Reforestation of Brown Coal Dumps in Bashkortostan: Characteristics of the Soil and the Condition of Birch (Betula pendula Roth) Stands (Results of a 35-year Experiment)

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    In 1980–1984, reforestation of the dumps of the Kumertau brown coal deposit (Republic of Bashkortostan, Russia) was carried out. Birch stands were created on the dumps of overburdened rocks. The authors studied the agrochemical properties of soils, described the state of birch stands and established the patterns of metalaccumulation in birch organs 35 years after reforestation. It is established that 35 years after planting birch trees on the dumps, the trees are characterized as ‘healthy’. The concentration of copper, zinc, lead and cadmium in birch organs changes in the following sequence: root system > bark > shoots > leaves. Soil formation processes are noted in birch stands on dumps. The upper (0–20 cm) soil layer acidity shifted bytwo units to the acidic side. There is a slight decrease in the content of phosphorus and the exchange forms of calcium and magnesium. Thus, birch is a promising tree species for the reforestation of mining industry dumps. Keywords: dumps, reforestation, Betula pendula Roth, metal accumulation, soil formation processe

    DNA authentication technologies for product quality monitoring in the wine industry

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    Identification of wine product authenticity is a topical question in theRussian Federation. A solution to this problem can be DNA authentication of wines, which is a technological process of product authenticity control using genetic identification of the main plant ingredient — wine grape varieties. This type of wine verification is carried out by analyzing residual amounts of Vitis vinifera L. nucleic acids extracted from cell debris of final products by molecular genetic methods. The aim of this work is the analysis of the existing methods for extraction of nucleic acids from grapes, wine raw materials and commercial wines, as well as description of the molecular genetic approaches to technical genetic identification of grape varieties and authentication of wines made from them. The obtained data suggest suitability of DNA authentication of wine products as a supplement to earlier approved analytical methods (documentary, visual, sensory, physico-chemical)
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