活性碳上羧酸根锚定AuCl3催化乙炔氢氯化反应的理论研究

采用密度泛函B3LYP方法,运用分子模型对活性碳（AC）上羧酸根负载AuClx催化剂的活性结构、稳定性以及催化乙炔氢氯化反应机制进行了详细的理论探讨。结果表明,AuCl3催化剂可以被表面羧酸根单中心级分散锚定,形成AC-COOH-AuCl3表面活性中心,进而在氢氯化过程中与乙炔发生协同加成生成氯乙烯,同时形成具有螯合结构的表面活性中心AC-CO2>AuCl2,进而催化氢氯化反应遵循分步反应异步加成机制:乙炔活化吸附到Au（Ⅲ）中心,HCl异裂亲核加成到乙炔伴随羧酸根质子化,分子内质子迁移形成Au（Ⅲ）-氯乙烯d-π配键络合物,氯乙烯脱除恢复AC-CO2>AuCl2螯合结构。计算还表明,AC-COOH-AuCl3表面活性中心比Au2Cl6催化组分更不易被乙炔还原失活。国家自然科学基金(91545105,21273177

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