25,278 research outputs found

    Work Function of Single-wall Silicon Carbide Nanotube

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    Using first-principles calculations, we study the work function of single wall silicon carbide nanotube (SiCNT). The work function is found to be highly dependent on the tube chirality and diameter. It increases with decreasing the tube diameter. The work function of zigzag SiCNT is always larger than that of armchair SiCNT. We reveal that the difference between the work function of zigzag and armchair SiCNT comes from their different intrinsic electronic structures, for which the singly degenerate energy band above the Fermi level of zigzag SiCNT is specifically responsible. Our finding offers potential usages of SiCNT in field-emission devices.Comment: 3 pages, 3 figure

    Equation of state of a superfluid Fermi gas in the BCS-BEC crossover

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    We present a theory for a superfluid Fermi gas near the BCS-BEC crossover, including pairing fluctuation contributions to the free energy similar to that considered by Nozieres and Schmitt-Rink for the normal phase. In the strong coupling limit, our theory is able to recover the Bogoliubov theory of a weakly interacting Bose gas with a molecular scattering length very close to the known exact result. We compare our results with recent Quantum Monte Carlo simulations both for the ground state and at finite temperature. Excellent agreement is found for all interaction strengths where simulation results are available.Comment: 7 pages, 4 figures, published version in Europhysics Letters, a long preprint with details will appear soo

    Teleoperation experiments with a Utah/MIT hand and a VPL DataGlove

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    A teleoperation system capable of controlling a Utah/MIT Dextrous Hand using a VPL DataGlove as a master is presented. Additionally the system is capable of running the dextrous hand in robotic (autonomous) mode as new programs are developed. The software and hardware architecture used is presented and the experiments performed are described. The communication and calibration issues involved are analyzed and applications to the analysis and development of automated dextrous manipulations are investigated

    QUANTITATIVE MONITORING OF CEFRADINE IN HUMAN URINE USING A LUMINOL/SULFOBUTYLETHER-beta-CYCLODEXTRIN CHEMILUMINESCENCE SYSTEM

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    In this paper, a sensitive, rapid, and simple flow-injection chemiluminescence (FI-CL) technique is described for determining cefradine in human urine and capsule samples at the picogram level. The results show that cefradine within 0.1-100.0 nmol/L quantitatively quenches the CL intensity of the luminol/sulfo butylether-beta-cyclodextrin (SBE-beta-CD) system, with a relative correlation coefficient r of 0.9931. Subsequently, the possible mechanism for the quenching phenomenon is discussed in detail using the FI-CL and molecular docking methods. The proposed CL method, with a detection limit of 0.03 nmol/L (3 sigma) and relative standard deviations < 3.0% (N = 7), is then implemented to monitor the excretion of cefradine in human urine. After orally administration, the cefradine reaches a maximum value of 1.37 +/- 0.02 mg/mL at 2.0 h in urine, and the total excretion is 4.41 +/- 0.03 mg/mL within 8.0 h. The absorption rate constant k(a), the elimination rate constant k(e), and the half-life t(1/2) are 0.670 +/- 0.008 h(-1), 0.744 +/- 0.005 h(-1), and 0.93 +/- 0.05 h, respectively

    Performance of Photosensors in the PandaX-I Experiment

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    We report the long term performance of the photosensors, 143 one-inch R8520-406 and 37 three-inch R11410-MOD photomultipliers from Hamamatsu, in the first phase of the PandaX dual-phase xenon dark matter experiment. This is the first time that a significant number of R11410 photomultiplier tubes were operated in liquid xenon for an extended period, providing important guidance to the future large xenon-based dark matter experiments.Comment: v3 as accepted by JINST with modifications based on reviewers' comment
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