507 research outputs found

    Asymptotically exact probability distribution for the Sinai model with finite drift

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    We obtain the exact asymptotic result for the disorder-averaged probability distribution function for a random walk in a biased Sinai model and show that it is characterized by a creeping behavior of the displacement moments with time, ~ t^{\mu n} where \mu is dimensionless mean drift. We employ a method originated in quantum diffusion which is based on the exact mapping of the problem to an imaginary-time Schr\"{odinger} equation. For nonzero drift such an equation has an isolated lowest eigenvalue separated by a gap from quasi-continuous excited states, and the eigenstate corresponding to the former governs the long-time asymptotic behavior.Comment: 4 pages, 2 figure

    Research of mechanical stress at tension of quartz optical fiber (QOF)

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    The article presents the results of a study of the process of occurrence of mechanical stress and strain during stretching of a quartz optical fiber. The analysis and review of the current state of development of fiber-optic conductors is performed. The problems of occurrence of microcracks in the body of optical fibers during mechanical loading during operation are considered. In the process of winding optical fibers and further operation, cracks occur. The conducted research allows us to solve an important production problem related to increasing the strength of optical fibers and reducing the number of microcracks. The object of scientific research is quartz optical fiber of the G652 standard, used for the production of fiber-optic cables. For optical fibers, the greatest danger is the stretching, which is observed when rewinding the fiber, during its cabling, during the laying and operation of the optical cable. It was found that the mechanical tensile strength of G652 optical fiber was from 4 482 to 4 808 MPa, and the number of cracks and their parameters affect the tensile strength of the fiber

    Graphene-Paper-Based Electrodes on Plastic and Textile Supports as New Platforms for Amperometric Biosensing

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    The possibility of exfoliating graphite into graphene sheets allows the researchers to produce a material, termed “graphene paper” (G-paper), conductive as graphite but more flexible and processable. G-paper is already used for electronic applications, like conductors, antennas, and heaters, outperforming metal conductors thanks to its high flexibility, lightness, chemical stability, and compatibility with polymeric substrates. Here, the effectiveness in the use of G-paper for the realization of electrodes on flexible plastic substrates and textiles, and their applicability as amperometric sensors are demonstrated. The performance of these devices is compared with commercial platforms made of carbon-based inks, finding that they outperform commercial devices in sensing nicotinamide adenine dinucleotide (NADH), a key molecule for enzymatic biosensing; the electrodes can achieve state-of-the-art sensitivity (107.2 μA mm−1 cm−2) and limit of detection (0.6 × 10−6 m) with no need of additional functionalization. Thanks to this property, the stable deposition of a suitable enzyme, namely lactate dehydrogenase, on the electrode surface is used as a proof of concept of the applicability of this new platform for the realization of a biosensor. The possibility of having a single material suitable for antennas, electronics, and now sensing opens new opportunities for smart fabrics in wearable electronic applications

    Two-component liquid model for the quark-gluon plasma

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    We consider a two-component-liquid model, a la Landau, for the quark-gluon plasma. Qualitatively, the model fits well some crucial observations concerning the plasma properties. Dynamically, the model assumes the existence of an effective scalar field which is condensed. The existence of such a condensate is supported by lattice data. We indicate a possible crucial test of the model by lattice simulations.Comment: 5 pages; Talk given by V.I. Zakharov at 16th International Seminar on High Energy Physics (QUARKS-2010), Kolomna, Russia, 6-12 June, 201

    CHOICE OF CONDITIONS FOR GAS OUTFLOW IN VACUUM AND CONFIGURATIONS OF A FORMING UNIT FEEDING A WORKING SUBSTANCE INTO THE PLASMA VOLUME

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    The paper presents formulated requirements to the gas-dynamic device designed for working substance feeding into the ionization zone of plasmas facilities. The role of geometrical factors in formation of a supersonic flow is determined, as well as, the role of gasdynamic factors in attainment of necessary parameters beyond the forming element. The conditions for gas-dynamic flow clustering minimization in the course of outflow in vacuum

    Subjective factors and psychological characteristics of students’ selfrealization as a reflection of their psychological well-being in the process of university learning

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    The purpose of this research is to determine psychological conditions and signs of students’ selfrealization in university training. Psychological survey methods were used in this research. Students’ needmotivational features, meaning-setting characteristics, self-attitude properties and purposelife orientations were scrutinized. As a result the connection between the level of students’ selfrealization and positive motivation of learning, as well as integrity and meaning consistency of their Selfconcept is stated. The conclusion is made on necessity to apply individual-oriented forms of teachin

    Mobile technologies in implementation of programs of internal tourism development

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    Now a days great attention is paid to the programs of the development of domestic tourism, its informational support, the development of new tourist products. But in spite of efforts in this direction, the population of Russia still has not enough information about tourist recreational opportunities of particular regions and in the whole countr
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