2RUP_aR-2RRU并联机构性能分析与尺度优化

提出了一种新型面对称两移动两转动2RUPaR-2RRU并联机构，应用旋量理论分析其自由度，并确定了其运动特性。该机构可作为振动筛的本体结构。建立机构位置分析模型，得到位置逆解解析表达式；应用矢量法分析机构速度，得到输入、输出Jacobian矩阵，并据此分析了机构奇异位形；应用输入、输出传递指标评价机构运动和力传递性能，给出有效传递姿态工作空间和有效传递位置工作空间（Effective transmission positional workspace，ETPW）的定义和数值计算方法。以ETPW最大为目标，建立机构尺度参数约束优化模型，并应用差分进化算法求解该问题；给出了机构尺度优化设计实例。结果表明，模型和算法可行有效，优化后的机构ETPW明显增大

强红外激光引起BCl_3分子可见荧光的脉冲光-声-光效应

用时间、空间分辨的方法研究了OAO荧光对时间、空间的依赖关系。观察到反应池几何形状对OAO荧光的显著影响。记录了CO_2脉冲激光激发BCl_3分子时形成的脉冲声波,及其与OAO荧光的对应关系。证实了OAO荧光是脉冲声波对BCl_3激发态分子的再激发。用简单的模型计算了OAO荧光的形成、轴向移动速度,结果与实验基本一致

强红外激光引起BCl_3可见荧光的动力学研究

用TEA CO_2激光辐照纯BCl_3气体,观察到可见荧光具有多种过程。系统地测量了可见荧光的空间、时间、光谱结构,以及它们随激光能量、BCl_3气压等参数的依赖关系。用简化碰撞动力学模型讨论了BCl_3可见荧光过程,得到有效振动温度、可见荧光强度的分析表达式和ρT_延≌C/K(T_ν)的简单关系。理论与实验结果一致

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

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

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

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 p→νˉK+p\to \bar\nu K^+ Searches

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 $p\to \bar\nu K^+$ 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 $p\to \bar\nu K^+$ 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 $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel