7,616 research outputs found

    The Problem of Scheduling for the Linear Section of a Single-Track Railway with Independent Edges Orientations

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    The paper is devoted to the problem of scheduling for the linear section of a single-track railway: how to organize the ow in both directions in the most efficient way. In this paper, the authors propose an algorithm for scheduling with independent edges orientations, examine the properties of this algorithm and perform the computational experiments

    Nonequilibrium phenomena in multiple normal-superconducting tunnel heterostructures

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    Using the nonequilibrium theory of superconductivity with the tunnel Hamiltonian, we consider a mesoscopic NISINISIN heterostructure, i.e., a structure consisting of five intermittent normal-metal (N) and superconducting (S) regions separated by insulating tunnel barriers (I). Applying the bias voltage between the outer normal electrodes one can drive the central N island very far from equilibrium. Depending on the resistance ratio of outer and inner tunnel junctions, one can realize either effective electron cooling in the central N island or create highly nonequilibrium energy distributions of electrons in both S and N islands. These distributions exhibit multiple peaks at a distance of integer multiples of the superconducting chemical potential. In the latter case the superconducting gap in the S islands is strongly suppressed as compared to its equilibrium value

    Snow metamorphism: a fractal approach

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    Snow is a porous disordered medium consisting of air and three water phases: ice, vapour and liquid. The ice phase consists of an assemblage of grains, ice matrix, initially arranged over a random load bearing skeleton. The quantitative relationship between density and morphological characteristics of different snow microstructures is still an open issue. In this work, a three-dimensional fractal description of density corresponding to different snow microstructure is put forward. First, snow density is simulated in terms of a generalized Menger sponge model. Then, a fully three-dimensional compact stochastic fractal model is adopted. The latter approach yields a quantitative map of the randomness of the snow texture, which is described as a three-dimensional fractional Brownian field with the Hurst exponent H varying as continuous parameter. The Hurst exponent is found to be strongly dependent on snow morphology and density. The approach might be applied to all those cases where the morphological evolution of snow cover or ice sheets should be conveniently described at a quantitative level

    Search for new pharmacological targets for increasing the efficiency of correction of cardiovascular diseases

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    It is noted that currently, there are no drugs for specific pharmacological correction of endothelial dysfunction in cardiovascular diseases, and the search for new targets for pharmacological correction of endothelial dysfunction is one of the main tasks of pharmacolog
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