Properties of hybrid SPEK-C/GO composite proton exchange membranes

采用共混制备了一系列磺化含酚酞侧基聚芳醚酮(SPEk-C)/氧化石墨烯(gO)复合质子交换膜,系统地研究了gO含量对复合膜性能的影响。结果表明,gO含量对膜的离子交换容量、稳定性、质子电导率和甲醇渗透率等有重要影响。复合膜质子电导率随gO含量增加而提高,gO含量为2%和5%的复合膜在80℃下质子电导率均在10-1 S·CM-1以上。80℃下,gO含量为5%的复合膜甲醇渗透率为6.69x10-7 CM2·S-1,低于同温度下复合前SPEk-C膜1个数量级。复合后膜的化学稳定性增强,离子交换容量和含水率均有提高,相对选择性明显增大,最高达SPEk-C的18.2倍。A series of sulfonated phenolphthalein side poly(aryl ether ketone)(SPEK-C)/graphene oxide(GO) hybrid composite proton exchange membranes was fabricated.The effect of GO as a filler blending with SPEK-C was investigated systematically.The results indicated that GO content in the membrane had a great influence on ionic exchange capacity, stability, proton conductivity and methanol permeability.The proton conductivity was enhanced with increasing GO content.Moreover, the proton conductivity of the composite membranes with 2% and 5% GO was all above 10-1 S·cm-1 at 30℃.The composite membrane containing 5% GO exhibited methanol permeability of 6.7×10-8 cm2·s-1 at 30℃, which was one order of magnitude lower than that of SPEK-C membrane.The ionic exchange capacity, stability and water uptake were enhanced, and the relative selectivity reached up to 18.2 times higher than that of the SPEK-C membrane.福建省科技计划项目(2014H0043

内部构件对循环流化床颗粒径向分布的影响

本文考察了园环、锥斗及多孔板构件对循环流化床径向颗粒分布的影响。实验及分析表明,循环流化床中径向颗粒分布的不均匀起因于气固流动系统中的湍流不均匀因素,多孔板构件是改善径向颗粒不均匀的较好结构,合理地设计多孔板开孔方式及边缝尺寸,可使径向分布趋于均匀。本文还对多孔板的影响范围及多层构件对径向颗粒分布的影响进行了研究,结果表明,多孔板的有效影响范围相当于床径两倍的尺寸,采用多层构件可提高平均颗粒浓度

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

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