单壁碳纳米管内腔中的分子行为

单壁碳纳米管可以作为纳米尺度的分子容器装填多种分子. 结合高分辨透射电子显微镜的原位表征技术, 将分子装填进入单壁碳纳米管的内腔中为在原子尺度研究分子的结构和化学性质提供了一种有效的策略. 碳纳米管内腔的限域效应往往会驱使装填分子形成一些与体相中完全不同的全新结构, 同时也经常会对化学反应的路径产生显著影响. 碳纳米管还可以充当模板, 影响内腔中化学反应的产物结构. 本综述总结了装填分子在碳纳米管内腔中形成的独特结构、碳纳米管内腔中分子的化学反应研究以及装填分子与碳纳米管内壁之间的化学反应. Single-walled carbon nanotubes can be used as nano-scale molecular containers to encapsulate a variety of molecules. Combined with the in-situ high-resolution transmission electron microscopy, molecules encapsulation of single-walled carbon nanotubes provides a powerful strategy for studying the structure and chemical properties of molecules at the atomic scale. The confinement effect of the inner cavity of carbon nanotubes often drives the encapsulated molecules to form new structures that are completely different from those in the bulk phase. At the same time, it also often has a significant impact on the pathways of chemical reactions. Carbon nanotubes can also act as a template, affecting the structure of the product of the chemical reaction in the inner cavity. In this review, we summarized the unique structure formed by the encapsulated molecules in single-walled carbon nanotubes, the research on the chemical reactions of the encapsulated molecules, and the chemical reactions between the encapsulated molecules and the inner walls of the carbon nanotubes. © 2022 Science Press (China). All Rights Reserved

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

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors

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