12 research outputs found

    十一五水动力学发展规划的建议

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    水动力学是流体力学的一个重要分支,有着悠久的研究与发展历史,形成了比较完整的学科体系.进入21世纪以来,资源开发、环境保护、国家安全已成为世界各国普遍关注的战略问题.我国的海防建设、海洋资源开发与海洋空间利用、海岸带综合规划和水环境保护、水资源开发与利用等为水动力学研究提出了新的迫切需求.本文阐述了水动力学研究的国家需求、国内外水动力学研究的现状和发展趋势,提出了近期有待研究的主要科学问题

    Hybrid simulated annealing-hill climbing algorithm for fast aberration correction without wavefront sensor

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    新疆气候变化及短期气候预测综合系统研究

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    该项目提出了现代气候观新概念,并深刻地阐述了其科学内涵,并研究指出现代气候观是一个相互联系和作用的观念系统包括气候系统观、气候资源观、气候环境观、气候变化观、气候层次观。项目还揭示出新疆气候变化和三大气候灾害——新疆春季水旱、夏季洪涝和夏秋季低温冷害的若干新现象、新事实,并对其形成原因、物理机制和预测应用进行了新的探索,同时研制成了2000新一代《短期气候预测综合业务系统》。该项目研究与世界气象组织提出的全球气候变化研究规划在时间上恰好是一致的,并始终紧贴自治区以一白(棉花)一黑(石油)为重点的优势资源转换发展战略和以生态环境保护和建设为根本和切入点的西部大开发战略,坚持边研究、边行动、边应用的原则,在“用”上下功夫,取得了显著的社会、经济、环境和气象业务效益

    Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024*

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    Determination of the number of ψ(3686) events taken at BESIII

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    The number of ψ(3686) events collected by the BESIII detector during the 2021 run period is determined to be (2259.3±11.1)×106 by counting inclusive ψ(3686) hadronic events. The uncertainty is systematic and the statistical uncertainty is negligible. Meanwhile, the numbers of ψ(3686) events collected during the 2009 and 2012 run periods are updated to be (107.7±0.6)×106 and (345.4±2.6)×106, respectively. Both numbers are consistent with the previous measurements within one standard deviation. The total number of ψ(3686) events in the three data samples is (2712.4±14.3)×10^

    JUNO Sensitivity on Proton Decay pνˉK+p\to \bar\nu K^+ Searches

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    The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in pνˉK+p\to \bar\nu K^+ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via pνˉK+p\to \bar\nu K^+ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is 9.6×10339.6 \times 10^{33} years, competitive with the current best limits on the proton lifetime in this channel

    JUNO sensitivity on proton decay p → ν K + searches*

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    The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the pνˉK+ p\to \bar{\nu} K^+ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via pνˉK+ p\to \bar{\nu} K^+ is 36.9% ± 4.9% with a background level of 0.2±0.05(syst)±0.2\pm 0.05({\rm syst})\pm 0.2(stat) 0.2({\rm stat}) events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is 9.6×1033 9.6 \times 10^{33} years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies

    Measurement of integrated luminosity of data collected at 3.773 GeV by BESIII from 2021 to 2024

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    We present a measurement of the integrated luminosity e+e- of collision data collected by the BESIII detector at the BEPCII collider at a center-of-mass energy of Ecm = 3.773 GeV. The integrated luminosities of the datasets taken from December 2021 to June 2022, from November 2022 to June 2023, and from October 2023 to February 2024 were determined to be 4.995±0.019 fb-1, 8.157±0.031 fb-1, and 4.191±0.016 fb-1, respectively, by analyzing large angle Bhabha scattering events. The uncertainties are dominated by systematic effects, and the statistical uncertainties are negligible. Our results provide essential input for future analyses and precision measurements
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