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81.
Multi-gap Resistive Plate Chamber (MRPC) is a new generation of gas detector with good tim-ing and spacial resolution, whose technique is widely applied in some recent high energy (nuclear) physics experiments. In this letter, we report a long-strip two-end readout MRPC and its test beam performance. The measurements show that the long-strip performs a transmission line characteristic and the impedance is independent of the length of strip. The MRPC module we developed is presented to gain a timing resolution of~80 ps and a spacial resolution of ~6.4 mm. The possible application of the MRPC is also discussed. 相似文献
82.
丝状液晶5CB与铁(Ⅲ)卟啉之间的轴向配位作用 总被引:1,自引:0,他引:1
通过考察掺杂配位性质不同的两种铁(Ⅲ)卟啉的丝状液晶5CB在磁场下的行为以及UV-Vis光谱,研究了液晶5CB与铁(Ⅲ)卟啉的轴向配位作用.结果表明,弗雷德里克兹转变阈值的降低和Soret带随着液晶5CB含量增大而红移是液晶5CB与五配位Fe(TPCl发生轴向配位的结果. 相似文献
83.
多壁纳米碳管空气电极的交流阻抗研究 总被引:10,自引:0,他引:10
研究了多壁纳米碳管、活性炭和石墨等空气电极的交流阻抗特性.结果表明,纳米碳管空气电极的阻抗谱由两个半圆组成,高频区半圆对应欧姆极化阻抗,低频区半圆对应电化学极化阻抗.催化剂Pt以纳米颗粒的形式沉积在碳管的外表面,明显减小了电极的欧姆阻抗和电化学极化阻抗,提高了氧还原反应的电催化活性.活性炭电极除存在电化学阻抗外,还存在薄液膜扩散阻抗(Nernst扩散),石墨电极形成的薄液膜反应区域较小,电极反应呈Warburg扩散阻抗特征,相应的电催化活性较低.采用交流阻抗等效电路分析方法,对拟合的动力学数据进行了解释. 相似文献
84.
WANG Xiao-Bin CHEN Guo-Ming LI Zu-Hao CHEN Gang YANG Ming YANG Zhao-Yu ZHANG Shao-He LU Yu-Sheng CHEN He-Sheng 《中国物理C(英文版)》2005,29(11):1071-1076
Analyzing methods on the angular resolution of lead-scintillating fiber electromagnetic calorimeter are studied. The space resolution function, which is used to calculate weights,is extracted from Monte-Carlo simulation. Better angular resolution was obtained from the beam test data of AMS ECAL in 2002 at CERN, when the space resolution function was used in the fit. Different ways to calculate the centers of gravity,to choose the layers to fit the incidence direction are also discussed. 相似文献
85.
86.
The electronic and structural properties of ReO5 and ReO5 clusters are investigated using density functional theory (DFT) calculations. The lowest energy structures for both the anionic and neutral clusters are determined, and the corresponding photoelectron spectrum is simulated. Our results show that ReO5 can be described as an unusual peroxo molecule, Re(O)3(η2-O2) , while ReO5 is found to be exhibiting the O2 o radical character. Molecular orbital analyses and spin density analyses are performed to elucidate the chemical bonding and the electronic and structural properties in these two rhenium oxide clusters. 相似文献
87.
Feng L Jia XB Jiang J Zhu MM Chen Y Tan XB Shi F 《Molecules (Basel, Switzerland)》2010,15(11):7893-7906
The efficacy of Prunella extracts in the prevention and treatment of lung cancer has been attributed to different components. In this study, an "active components combination model" hypothesis was proposed to explain the anti-tumor activity of Prunella. The efficacy of Prunella extracts from different regions was compared in vitro and in vivo, and the TNF-α activity in serum of tumor-bearing mice was also evaluated. High performance liquid chromatography (HPLC) was used to analyze the extracts and identify 26 common peaks. Prunella samples from different regions were classified by the cluster analysis method; both P. vulgaris L. from Bozhou and P. asiatica Nakai from Nanjing, which had the highest activities, were further divided into different classes. Six peaks from the HPLC analysis were very similar, and were identified as caffeic acid, rosmarinic acid, rutin, quercetin, oleanolic acid and ursolic acid. The total ratio of these compounds in Prunella from Bozhou and Nanjing were 1.0:14.7:3.9:1.0:4.4:1.4 and 1.0:14.8:4.0:0.8:5.6:1.8, respectively. Total triterpenes and total phenols in Prunella were separated by macroporous resin purification for activity studies. The results showed that total triterpenes and total phenols had anti-lung cancer activity and their combination significantly enhanced the activity. In addition, the combination also significantly increased the TNF-α content compared to total triterpenes or total phenols. The results indicated that the efficacy of Prunella against lung cancer was attributable to multiple components acting at an optimal ratio. 相似文献
88.
LIANG Yu-Tie MAO Ya-Jun YOU Zheng-Yun LI Wei-Dong BIAN Jian-Ming CAO Guo-Fu CAO Xue-Xiang CHEN Shen-Jian DENG Zi-Yan FU Cheng-Dong GAO Yuan-Ning HAN Lei HAN Shao-Qing HE Kang-Lin HE Miao HU Ji-Feng HU Xiao-Wei HUANG Bin HUANG Xing-Tao JIA Lu-Kui JI Xiao-Bin LI Hai-Bo LIU Bei-Jiang LIU Chun-Xiu LIU Huai-Min LIU Ying LIU Yong LUO Tao LU Qi-Wen MA Qiu-Mei MA Xiang MAO Ze-Pu MO Xiao-Hu NING Fei-Peng PING aong-Gang QIU Jin-Fa SONG Wen-Bo SUN Sheng-Sen SUN Xiao-Dong SUN Yong-Zhao TIAN Hao-Lai WANG Ji-Ke WANG Liang-Liang WEN Shuo-Pin WU Ling-Hui WV Zhi XIE Yu-Guang XU Min YAN Jie YAN Liang YAO Jian YUAN Chang-Zheng YUAN Ye ZHANG Chang-Chun ZHANG Jian-Yong ZHANG Lei ZHANG Xue-Yao ZHANG Yao ZHENG Yang-Heng ZHU Yong-Sheng ZOU Jia-Heng 《中国物理C(英文版)》2009,33(7)
Cosmic-ray data of 90 M events have been collected and used for calibration, alignment as well as detector tuning. A special tracking algorithm for the BESⅢ muon counter is developed and verified with Monte-Carlo simulation and then further confirmed with the cosmic-ray data. The obtained strip resolutions are in good agreement with the design values. A new alignment approach for the BESⅢ muon counter is confirmed with the cosmic-ray data and proposed to be used in future analysis of experimental data. 相似文献
89.
采用表面解吸常压化学电离(SDAPCI)串联质谱成像技术,建立了一种能在无需样品预处理条件下直接对土壤中的塑化剂邻苯二甲酸二乙酯(DEP)的分布情况进行分析的新方法。利用碰撞诱导解离串联质谱法对待测物母离子进行了结构鉴定,排除检测结果的假阳性;分别选择质子化DEP(m/z 223)及其特征峰碎片离子(m/z 177)对土壤固体表面进行二维质谱扫描,通过质谱成像数据处理获得DEP的一二级质谱影像图。结果表明,未经任何样品预处理的实际土壤固体表面的DEP呈团簇或颗粒状不均匀分布,经雨水浸润后的土壤样品中的DEP分布发生了变化。本方法获得的空间分辨率为0.25 mm2,单个像素的采集时间为4.5 s,为复杂基体中塑化剂的含量和分布情况的研究提供了一种新思路。 相似文献