激光冲击强化对7075铝合金干摩擦特性的实验研究

实验研究了激光冲击强化对7075铝合金干摩擦性能的影响。通过对激光冲击强化前后的试件进行物相分析、硬度分析、残余应力分析以及金相组织分析,总结激光冲击强化改善7075铝合金耐磨性的原因。结果表明,激光冲击强化能使材料表面产生晶粒细化,提高材料的表面硬度,产生残余压应力;经过激光冲击强化处理之后7075铝合金的磨损量降低43.63%;磨痕的深度和宽度分别降低45.76%和18.84%,并且摩擦系数明显降低。激光冲击强化是一种能够有效改善7075铝合金耐磨性能的表面处理技术

石英玻璃旋转超声铣削表面质量研究

探索了高频旋转超声铣削石英玻璃的工艺规律与材料去除机理,检测分析了加工表面粗糙度与表面形貌,借助Matlab平台建模仿真了进给速度和主轴转速对磨粒运动轨迹的影响规律,研究了进给速度、主轴转速、切削宽度以及切削深度对加工表面质量的影响规律与机理。进给速度增大会导致刀具上的单颗金刚石磨粒的切削速度增大,参与切削的摆线平面投影运动轨迹变长,使表面粗糙度随进给速度增加先增大后减小;表面粗糙度值随主轴转速的增大总体上呈现出先减小后增大的趋势,主轴转速为3 000 r/min时铣削表面粗糙度最小;表面粗糙度值随切削宽度增大先增大后减小,切削宽度直接决定相邻刀具路径对应加工区域重叠范围,进而产生不同的磨粒划刻加工叠加效果;随切削深度增大,表面粗糙度值呈现出先增大后减小再增大的趋势,铣削过程中超声振动与切削深度配合产生的近成形表面材料去除模式对表面质量具有关键性作用。研究工作可为石英玻璃旋转超声铣削加工提供一定的工艺基础

基于LS-DYNA的石英玻璃旋转超声铣削仿真研究

基于LS-DYNA有限元仿真平台对石英玻璃旋转超声铣削过程进行了建模仿真,分析了材料去除过程中刀—工作用区应力场分布特性,研究了金刚石刀具高频往复冲击时复合作用导致的裂纹萌生与扩展以及材料去除机理。对比超声辅助端面铣削试验结果,在一定程度上验证了有限元仿真模型的有效性

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

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

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 $p\to \bar{\nu} K^+$ 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 $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies