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951.
The threshold photoelectron spectrum of the C2H3Cl molecule is studied by using synchrotron radiation light source and supersonic molecular beam. The vertical ionization
potentials of different orbital electrons and some vibrational structures are obtained. The observed Rydberg autoionization
peaks are assigned by A2A1 state of C2H3Cl+. 相似文献
952.
Dexian Zheng Yiping He Yanxin Liu Yong Zheng Sheng Xiao Yin Liu Shilian Liu 《科学通报(英文版)》1998,43(17):1480-1485
CD3ε of T cell antigen receptor complex (TCR/CD3) plays an important role in the resembling of the complex and activation
signaling through its conservative immunoreceptor tyrosine-based activation motif (ITAM) in the cytoplasmic tall. Previous
study showed that a chimera molecule, consisting of the extracellular-transmembrane domain of human CD8α fused to the cytoplasmic
domain of CD3ε, induced apoptosis of T lymphocytes, indicating that apoptotic signals were transduced through the CD3ε-ITAM.
To elineate involvement of the two tyrosines in apoptotic signaling pathway, cDNAs with mutations at Y170F, Y181F and Y170F/Y181F
in CD8ε-ITAM were made by point mutation and PCR, and then cloned into pcDNA3 eukaryotic expression vectors. Stable expression
cell lines were established after transfection of the expression vectors into CD8- Jurkat T lymphocytes. Stimulation of these cell lines with anti-CD8 monoclonal antibody showed that only the cells with expression
of wild type chimera CD8-ε died by apoptosis, but not those cells with expressions of mutated CD8-ε chimera, indicating that
the two tyrosines in CD3ε-ITAM were required for the apoptotic signal transduction in T lymphocytes. 相似文献
953.
Xia Sun Ping Tang Yue Chen Zhen Huang Guang Li Zhimin Liu Zhiyou Chen Sheng Wang Songliu Yuan 《科学通报(英文版)》1998,43(17):1442-1442
The temperature dependence of resistance and magnetoresistance at 77 K for Cu-doped La 2/3Ca 1/3Mn 1-xCu xO-3 have been investigated. Besides the transition similar to the Cu-free sample at ~260 K, a new transition at lower temperature appears for Cu-doped samples. The new transition moves toward low temperature with increasing of Cu content. A new conductive proceeding related to Cu ion may exist. Magnetoresistance at liquid nitrogen shows that MR increased three orders when x is changed from 0 to 0 15. Moreover, the main variation of magnetoresistance is below the field of 1 T. 相似文献
954.
An approach to calculate the sound field generated by the Vibrating surface of a body with arbitrary shape moving at a small
mach number has been developed by using acoustical analogy. A governing equation to calculate the sound pressure on the surface
exited by its vibration has been derived on the basis of the united aerodynamics and aeroacoustics approach by Farassat and
Long, and the sound field would be determinate. The cases relating to the sound sources of static sphere and moving compact
pulsating sphere give a good check for the approach. 相似文献
955.
The relative contents of normal alkanes and isoprenoid alkanes from pyrolysed pmducts of green algaChlorella protothecoides increased when the algal cell subject to hydrolysis and bacterial degradation were wed. Their value of C23-/C
24+ and the rate of Pr/C17 increased greatly whereas the contents of C20 alkenes were remarkably low compared with that from untreated sample (as control). These results are more analogous to the
formation process of hydrocarbons derived from algae in natural geological environment. 相似文献
956.
地椒草制取叶绿素铜钠的研究 总被引:16,自引:0,他引:16
以地椒草为原料,乙醇为提取剂提取叶绿素,再经皂化、铜代、成盐制成叶绿素铜钠,产品质量达到国家GB3262—82标准。 相似文献
957.
用n阶代数多项式及指数型整函数的最佳逼近阶刻划了Bosov空间的特征。 相似文献
958.
结合C市电业局光缆通信网的规划设计工作实际,分析了电力通信专网在线路建设、承载业务、网络拓扑、设备选型等方面的特点,提出了一个适合于大中城市电业局光缆通信网的组网方案。该方案客观地分析了电力部门业务需求,为组网建设节省了近1/3的投资,同时为通信系统提供了近2倍的传输电路。 相似文献
959.
研究高速铁路双线简支梁桥的空间振动响应.建立了考虑双线简支梁在车辆蛇行和单线行车时的偏心荷载作用下车桥系统空间耦联作用的振动力学分析模型,以20m和48m简支梁桥为例,在计算机上模拟列车过桥的全过程,通过分析动力响应,得出了一些有工程意义的结论. 相似文献
960.
小波神经网络及其在旋转机械轴心轨迹识别中的应用 总被引:3,自引:0,他引:3
提出一种基于小波变换理论的小波神经网络模式识别方法,并将该方法应用于旋转机械轴心轨迹的识别。在本文提出的方法中,模式识别分两步来完成。第一步通过小波网络完成对数据的压缩,第二步应用前馈神经网络对第一步中的压缩数据进行学习与分类,从而达到模式识别的目的。 相似文献