新型水导激光水-气缩流机理分析及初步加工试验验证

水导激光加工技术因加工材料表面热影响小,加工深度能力强等优点展现出优越的加工能力。研究基于水导激光加工机理,提出一种新型水导激光缩流导光方法,分析了缩流机理,并通过激光与缩流层流水柱高效耦合试验与材料加工试验验证其加工方法可行性。试验结果表明,保持气压不变,随着水压的增大,缩流层流水柱的速度、直径及长度不断增大;保持水压不变,随着气压的增大,层流水柱速度逐渐增大,直径和长度逐渐减小。同时,通过调节激光与层流水柱耦合最优传导激光条件下进行加工试验。对比空气中加工结果,水-气缩流传导激光加工技术在热影响区和热堆积上有明显的改善,初步验证新型水-气缩流传导激光加工技术的可行性

高温离子热快速合成AlPO_4-42分子筛

本文采用离子热合成法,以磷酸为磷源、异丙醇铝为铝源,在溴化1-丁基-3-甲基咪唑鎓([BMIM]Br)离子液体中于280℃快速合成了AlPO_4-42分子筛,并用该方法快速合成了其他类型的磷酸铝分子筛。通过X射线衍射、扫描电镜、比表面积孔隙率分析、固体核磁等表征手段研究了不同物料配比、模板剂、晶化时间对合成AlPO_4-42分子筛的影响以及AlPO_4-42分子筛的比表面积、孔容大小和孔道中的填充物。结果发现,在4min时已经形成了AlPO_4-42分子筛的结构。合成出的AlPO_4-42分子筛具有十四面体的形貌,这与采用常规方法得到的AlPO_4-42分子筛晶体的立方体形貌明显不同,而且AlPO_4-42分子筛的比表面积和孔容都有所改变。在合成AlPO_4-42分子筛的过程中离子液体和模板剂协同导向产物的形成

一种SiO<sub>2<-sub>纳米丝增强二氧化硅气凝胶复合材料及其制备方法

本发明公开了一种SiO2纳米丝增强二氧化硅气凝胶复合材料，该材料由长度为0.05～100μm的SiO2纳米丝和二氧化硅气凝胶复合而成，以二氧化硅气凝胶为基体，SiO2纳米丝为增强体，SiO2纳米丝的含量为复合材料总质量的0.5～40％。还公开了一种SiO2纳米丝增强二氧化硅气凝胶复合材料的制备方法，包括：在二氧化硅溶胶中加入长度为0.05～100μm的SiO2纳米丝，使SiO2纳米丝和二氧化硅溶胶混合分散均匀，在形成湿凝胶后经老化、改性及干燥步骤制得SiO2纳米丝增强二氧化硅气凝胶复合材料。本发明具有分散性好、相容性高等优点，二氧化硅气凝胶的力学性能有更好的提升，更能满足实际应用的需要

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