2,560 research outputs found

    Is there a renormalization of the 1D conductance in Luttinger Liquid model?

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    Properties of 1D transport strongly depend on the proper choice of boundary conditions. It has been frequently stated that the Luttinger Liquid (LL) conductance is renormalized by the interaction as ge2hg \frac{e^2} {h} . To contest this result I develop a model of 1D LL wire with the interaction switching off at the infinities. Its solution shows that there is no renormalization of the universal conductance while the electrons have a free behavior in the source and drain reservoirs.Comment: 5 pages, RevTex 2.0, attempted repair of tex error

    Negative local resistance caused by viscous electron backflow in graphene

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    Graphene hosts a unique electron system in which electron-phonon scattering is extremely weak but electron-electron collisions are sufficiently frequent to provide local equilibrium above liquid nitrogen temperature. Under these conditions, electrons can behave as a viscous liquid and exhibit hydrodynamic phenomena similar to classical liquids. Here we report strong evidence for this transport regime. We find that doped graphene exhibits an anomalous (negative) voltage drop near current injection contacts, which is attributed to the formation of submicrometer-size whirlpools in the electron flow. The viscosity of graphene's electron liquid is found to be ~0.1 m2^2 /s, an order of magnitude larger than that of honey, in agreement with many-body theory. Our work shows a possibility to study electron hydrodynamics using high quality graphene

    Electron transport through a mesoscopic metal-CDW-metal junction

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    In this work we study the transport properties of a finite Peierls-Fr\"ohlich dielectric with a charge density wave of the commensurate type. We show that at low temperatures this problem can be mapped onto a problem of fractional charge transport through a finite-length correlated dielectric, recently studied by Ponomarenko and Nagaosa [Phys. Rev. Lett {\bf 81}, 2304 (1998)]. The temperature dependence of conductance of the charge density wave junction is presented for a wide range of temperatures.Comment: Latex, Revtex 3.0, 7 pages, 2 EPS figures (uses epfs

    PHARMACOECONOMICS OF APPLICATION OF HEPATOPROTECTORS IN THERAPY OF DRUG-INDUCED LIVER INJURY AFTER CHEMOTHERAPY

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    One of the major problems of modern oncology drug is liver damage, requiring additional costs for its treatment. The aim of our work was to study medical and economic efficiency of various schemes of hepatoprotective treatment of toxic liver damage. The paper presents the use of pharmacoeconomic studies in the treatment of hepatic drug-induced hepatitis, which occurs after chemotherapy in patients with Hodgkin's lymphoma. The study was conducted in the two comparison groups on a "cost - effectiveness". This method was chosen because it is in effect depending on the process (method), treatment was varied, as well as costs incurred. The unit of the effect of the number of days required for the relief of hepatic failure has been selected. Economic analysis of the work includes not only toxic hepatitis therapy, and treatment of any disease complications such as hepatic encephalopathy. The study revealed that the effectiveness of therapy increased 1.4 times and the economic costs were 51.8 % reduced with hepatoprotective drug "remaxol"

    Atomically thin boron nitride: a tunnelling barrier for graphene devices

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    We investigate the electronic properties of heterostructures based on ultrathin hexagonal boron nitride (h-BN) crystalline layers sandwiched between two layers of graphene as well as other conducting materials (graphite, gold). The tunnel conductance depends exponentially on the number of h-BN atomic layers, down to a monolayer thickness. Exponential behaviour of I-V characteristics for graphene/BN/graphene and graphite/BN/graphite devices is determined mainly by the changes in the density of states with bias voltage in the electrodes. Conductive atomic force microscopy scans across h-BN terraces of different thickness reveal a high level of uniformity in the tunnel current. Our results demonstrate that atomically thin h-BN acts as a defect-free dielectric with a high breakdown field; it offers great potential for applications in tunnel devices and in field-effect transistors with a high carrier density in the conducting channel.Comment: 7 pages, 5 figure
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