1,301 research outputs found

    An Approach to Automatically Constructing Domain Ontology

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    PACLIC 20 / Wuhan, China / 1-3 November, 200

    A Nonlinear Lagrange Algorithm for Stochastic Minimax Problems Based on Sample Average Approximation Method

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    An implementable nonlinear Lagrange algorithm for stochastic minimax problems is presented based on sample average approximation method in this paper, in which the second step minimizes a nonlinear Lagrange function with sample average approximation functions of original functions and the sample average approximation of the Lagrange multiplier is adopted. Under a set of mild assumptions, it is proven that the sequences of solution and multiplier obtained by the proposed algorithm converge to the Kuhn-Tucker pair of the original problem with probability one as the sample size increases. At last, the numerical experiments for five test examples are performed and the numerical results indicate that the algorithm is promising

    Exploring the dark matter inelastic frontier with 79.6 days of PandaX-II data

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    We report here the results of searching for inelastic scattering of dark matter (initial and final state dark matter particles differ by a small mass splitting) with nucleon with the first 79.6-day of PandaX-II data (Run 9). We set the upper limits for the spin independent WIMP-nucleon scattering cross section up to a mass splitting of 300 keV/c2^2 at two benchmark dark matter masses of 1 and 10 TeV/c2^2.Comment: 5 pages, 6 figure

    Self-synchronization theory of a nonlinear vibration system driven by two exciters. Part 1: Theoretical analysis

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    A single mass vibration system driven by two counter-rotating motors is studied in this paper. The nonlinear factor of vibration spring in the vertical direction is considered. Based on the Lagrange Equations, the mechanic-electric coupling dynamic equation of the vibration system is established. The condition of the self-synchronization implementation of the system is obtained by using the Hamilton theory. Applying once approximate method of nonlinear system stability, the asymptotic stability condition of the vibration system at equilibrium point is deduced. They provide theoretical basis for the simulation of self-synchronization of vibration system

    Arborinol methyl ether from Areca catechu L.

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    The title compound isolated from Areca catechu L. (common name: arborinol methyl ether; a member of the arborane family) was established as 3α-methoxyarbor-9(11)-ene, C31H52O. Rings A/B/C/D assume a chair conformation, while ring E has an envelope conformation. The absolute configuration was determined to be (3R,5R,8S,10S,13R,14S,17S,18S, 21S) by analysis of Bijvoet pairs based on resonant scattering of light atoms, yielding a Hooft parameter y of −0.03 (3)

    Self-synchronization theory of a nonlinear vibration system driven by two exciters. Part 2: Numeric analysis and experimental verification

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    A single mass nonlinear vibration machine driven by two counter-rotating motors was taken as a research object. Based on the mechanic-electric coupling dynamic equation of the vibration machine and the electromagnetic torque model of motor, the simulation model was established. By using the actual parameters of the vibration machine, the numerical simulation of a single-mass nonlinear vibration system under three typical working states was performed. When two motors were working under the ideal state, or when the overlap angle of two eccentric blocks were different, or when the supply frequency of one motor was changed, the two motors can achieve steadily synchronous motion if parameters of the vibration system are in specific range. Finally, the self-synchronization experiment was carried out under the three working states. A comparison of experimental results with simulation results shows that the numerical simulation is accurate

    Low-mass dark matter search results from full exposure of PandaX-I experiment

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    We report the results of a weakly-interacting massive particle (WIMP) dark matter search using the full 80.1\;live-day exposure of the first stage of the PandaX experiment (PandaX-I) located in the China Jin-Ping Underground Laboratory. The PandaX-I detector has been optimized for detecting low-mass WIMPs, achieving a photon detection efficiency of 9.6\%. With a fiducial liquid xenon target mass of 54.0\,kg, no significant excess event were found above the expected background. A profile likelihood analysis confirms our earlier finding that the PandaX-I data disfavor all positive low-mass WIMP signals reported in the literature under standard assumptions. A stringent bound on the low mass WIMP is set at WIMP mass below 10\,GeV/c2^2, demonstrating that liquid xenon detectors can be competitive for low-mass WIMP searches.Comment: v3 as accepted by PRD. Minor update in the text in response to referee comments. Separating Fig. 11(a) and (b) into Fig. 11 and Fig. 12. Legend tweak in Fig. 9(b) and 9(c) as suggested by referee, as well as a missing legend for CRESST-II legend in Fig. 12 (now Fig. 13). Same version as submitted to PR

    Dark Matter Results From 54-Ton-Day Exposure of PandaX-II Experiment

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    We report a new search of weakly interacting massive particles (WIMPs) using the combined low background data sets in 2016 and 2017 from the PandaX-II experiment in China. The latest data set contains a new exposure of 77.1 live day, with the background reduced to a level of 0.8×103\times10^{-3} evt/kg/day, improved by a factor of 2.5 in comparison to the previous run in 2016. No excess events were found above the expected background. With a total exposure of 5.4×104\times10^4 kg day, the most stringent upper limit on spin-independent WIMP-nucleon cross section was set for a WIMP with mass larger than 100 GeV/c2^2, with the lowest exclusion at 8.6×1047\times10^{-47} cm2^2 at 40 GeV/c2^2.Comment: Supplementary materials at https://pandax.sjtu.edu.cn/articles/2nd/supplemental.pdf version 2 as accepted by PR
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