1,079 research outputs found

    Spin Currents Induced by Nonuniform Rashba-Type Spin-Orbit Field

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    We study the spin relaxation torque in nonmagnetic or ferromagnetic metals with nonuniform spin-orbit coupling within the Keldysh Green's function formalism. In non-magnet, the relaxation torque is shown to arise when the spin-orbit coupling is not uniform. In the absence of an external field, the spin current induced by the relaxation torque is proportional to the vector chirality of Rashba-type spin-orbit field (RSOF). In the presence of an external field, on the other hand, spin relaxation torque arises from the coupling of the external field and vector chirality of RSOF. Our result indicates that spin-sink or source effects are controlled by designing RSOF in junctions.Comment: 3 figure

    Ferroelectric Nanotubes

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    We report the independent invention of ferroelectric nanotubes from groups in several countries. Devices have been made with three different materials: lead zirconate-titanate PbZr1-xTixO3 (PZT); barium titanate BaTiO3; and strontium bismuth tantalate SrBi2Ta2O9 (SBT). Several different deposition techniques have been used successfully, including misted CSD (chemical solution deposition) and pore wetting. Ferroelectric hysteresis and high optical nonlinearity have been demonstrated. The structures are analyzed via SEM, TEM, XRD, AFM (piezo-mode), and SHG. Applications to trenching in Si dynamic random access memories, ink-jet printers, and photonic devices are discussed. Ferroelectric filled pores as small as 20 nm in diameter have been studied

    Fluorescence kinetics of flavin adenine dinucleotide in different microenvironments

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    Fluorescence kinetics of flavin adenine dinucleotide was measured in a wide time and spectral range in different media, affecting its intra- end extramolecular interactions, and analyzed by a new method based on compressed sensing

    Theoretical Study on Transport Properties of Normal Metal - Zigzag Graphene Nanoribbon - Normal Metal Junctions

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    We investigate transport properties of the junctions in which the graphene nanoribbon with the zigzag shaped edges consisting of the NN legs is sandwiched by the two normal metals by means of recursive Green's function method. The conductance and the transmission probabilities are found to have the remarkable properties depending on the parity of NN. The singular behaviors close to E=0 with EE being the Fermi energy are demonstrated. The channel filtering is shown to occur in the case with N=N= even.Comment: 4 pages, 5 figure

    On the background in the γp→ω(π0γ)p\gamma p \to \omega(\pi^0\gamma) p reaction and mixed event simulation

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    In this paper we evaluate sources of background for the γp→ωp\gamma p \to \omega p, with the ω\omega detected through its π0γ\pi^0 \gamma decay channel, to compare with the experiment carried out at ELSA. We find background from γp→π0π0p\gamma p \to \pi^0 \pi^0 p followed by decay of a π0\pi^0 into two γ\gamma, recombining one π0\pi^0 and one γ\gamma, and from the γp→π0ηp\gamma p \to \pi^0 \eta p reaction with subsequent decay of the η\eta into two photons. This background accounts for the data at π0γ\pi^0 \gamma invariant masses beyond 700 MeV, but strength is missing at lower invariant masses which was attributed to photon misidentification events, which we simulate to get a good reproduction of the experimental background. Once this is done, we perform an event mixing simulation to reproduce the calculated background and we find that the method provides a good description of the background at low π0γ\pi^0 \gamma invariant masses but fakes the background at high invariant masses, making background events at low invariant masses, which are due to γ\gamma misidentification events, responsible for the background at high invariant masses which is due to the γp→π0π0p\gamma p \to \pi^0 \pi^0 p and γp→π0ηp\gamma p \to \pi^0 \eta p reactions.Comment: 10 pages, 5 figure

    X-ray Astronomy in the Laboratory with a Miniature Compact Object Produced by Laser-Driven Implosion

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    Laboratory spectroscopy of non-thermal equilibrium plasmas photoionized by intense radiation is a key to understanding compact objects, such as black holes, based on astronomical observations. This paper describes an experiment to study photoionizing plasmas in laboratory under well-defined and genuine conditions. Photoionized plasma is here generated using a 0.5-keV Planckian x-ray source created by means of a laser-driven implosion. The measured x-ray spectrum from the photoionized silicon plasma resembles those observed from the binary stars Cygnus X-3 and Vela X-1 with the Chandra x-ray satellite. This demonstrates that an extreme radiation field was produced in the laboratory, however, the theoretical interpretation of the laboratory spectrum significantly contradicts the generally accepted explanations in x-ray astronomy. This model experiment offers a novel test bed for validation and verification of computational codes used in x-ray astronomy.Comment: 5 pages, 4 figures are included. This is the original submitted version of the manuscript to be published in Nature Physic

    Molecular cloning and characterization of ABCG/PDR-type ABC transporter in grape berry skin

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    Grape (Vitis vinifera L.) skin contains the phenolic compound resveratrol which is important not only for resistance to biotic and abiotic stresses but also for human health. However, little is known about resveratrol transport in plant cells. ABC (ATP binding cassette) transporters are well-known transporters responsible for secondary metabolite accumulation in plants. Previous reports speculated that the full-size ABCG transporter pleiotropic drug-resistant (PDR) is involved in resveratrol transport in fungi and plants. In this paper, all full-size ABCG transporters found in the grape genome database are listed and focus is placed on VvABCG44/VvPDR14 as a candidate resveratrol transporter. The full-length cDNA of VvABCG44 was cloned by RT-PCR using mRNAs extracted from grape berry skin. VvABCG44 expression was induced by UV irradiation, and the expression pattern of VvABCG44 in various grape organs was similar to that of stilbene synthase (STS), a key enzyme in resveratrol synthesis. Resveratrol content in grape berry skin increased after UV irradiation. These results suggest that VvABCG44 functions as a resveratrol transporter in grape

    Measurement of the cross-section and forward-backward charge asymmetry for the b and c-quark in e+e- annihilation with inclusive muons at sqrt(s) = 58 GeV

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    We have studied inclusive muon events using all the data collected by the TOPAZ detector at sqrt(s)=58 GeV with an integrated luminosity of 273pb-1. From 1328 inclusive muon events, we measured the ratio R_qq of the cross section for qq-bar production to the total hadronic cross section and forward-backward asymmetry A^q_FB for b and c quarks. The obtained results are R_bb = 0.13+-0.02(stat)+-0.01(syst), R_cc = 0.36+-0.05(stat)+-0.05(syst), A^b_FB = -0.20+-0.16(stat)+-0.01(syst) and A^c_FB = -0.17+-0.14(stat)+-0.02(syst), in fair agreement with a prediction of the standard model.Comment: To be published in EPJ C. 24 pages, 12 figure
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