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851.
基于PEEC方法的平面电路EMC问题分析 总被引:4,自引:1,他引:3
提出了基于部分元等效电路(PEEC)方法求解印制板电路电磁兼容问题的新方法,即将印制板电路的辐射问题分为两步:(1)用部分元等效电路的方法确定印制板导体上的场源(电流)分布;(2)将所有电流元的辐射场进行叠加求总的辐射场。文中对上述方法进行了分析,在此基础上通过一个对称电路和一个非对称电路的辐射场计算,提出了一些工程设计中减小辐射的设计准则。 相似文献
852.
A gene expression atlas of the central nervous system based on bacterial artificial chromosomes 总被引:1,自引:0,他引:1
Gong S Zheng C Doughty ML Losos K Didkovsky N Schambra UB Nowak NJ Joyner A Leblanc G Hatten ME Heintz N 《Nature》2003,425(6961):917-925
The mammalian central nervous system (CNS) contains a remarkable array of neural cells, each with a complex pattern of connections that together generate perceptions and higher brain functions. Here we describe a large-scale screen to create an atlas of CNS gene expression at the cellular level, and to provide a library of verified bacterial artificial chromosome (BAC) vectors and transgenic mouse lines that offer experimental access to CNS regions, cell classes and pathways. We illustrate the use of this atlas to derive novel insights into gene function in neural cells, and into principal steps of CNS development. The atlas, library of BAC vectors and BAC transgenic mice generated in this screen provide a rich resource that allows a broad array of investigations not previously available to the neuroscience community. 相似文献
853.
Lu?PingEmail author Liu?Bin Zhang?Zhe Wu?Feng Deng?Nan-shengEmail author 《武汉大学学报:自然科学英文版》2003,8(4):1147-1152
Inclusion complex of Orange II with β-Cyclodextrin (β-CD) and the anti-photolysis effect under UV-light were investigated.
The molar ratio of inclusion complex of β-Cyclodextrin and Orange II is 1∶1. The formation constantK = 1.236×103 L/mol was determined by the UV and Fluorescence spectra respectively, which was quite in accordance with the calculation
with a modified Benesi-Hildbrand equation. The inclusion complex was characterized by the IR spectra and the molar ratio of
inclusion complex is 1∶1 too. The formation constantK = 1.266×103 L/mol was determined by1H NMR analysis and was nearly the same by UV and fluorescence spectra. The photocatalytic decolorization rate of Orange II
solutions containing β-CD and TiO2 was smaller by 51.9% than that of the Orange II solutions only containing TiO2, while in the case of direct photolysis of Orange II solutions, β-CD can lower the photolysis rate by 48.1% under UV-light.
This result indicates β-CD can inhibit the photolysis and photocatalytic decolorization of Orange II under UV-light. The β-CD
inclusion complex was found to be persistent to UV-light photolysis.
Foundation item: Supported by the National Natural Science Foundation of China (20177017)
Biography: Lu Ping (1958), male. Associate professor, research direction: environmental photochemistry. 相似文献
854.
Inada N Oguri M Pindor B Hennawi JF Chiu K Zheng W Ichikawa S Gregg MD Becker RH Suto Y Strauss MA Turner EL Keeton CR Annis J Castander FJ Eisenstein DJ Frieman JA Fukugita M Gunn JE Johnston DE Kent SM Nichol RC Richards GT Rix HW Sheldon ES Bahcall NA Brinkmann J Ivezić Z Lamb DQ McKay TA Schneider DP York DG 《Nature》2003,426(6968):810-812
Gravitational lensing is a powerful tool for the study of the distribution of dark matter in the Universe. The cold-dark-matter model of the formation of large-scale structures (that is, clusters of galaxies and even larger assemblies) predicts the existence of quasars gravitationally lensed by concentrations of dark matter so massive that the quasar images would be split by over 7 arcsec. Numerous searches for large-separation lensed quasars have, however, been unsuccessful. All of the roughly 70 lensed quasars known, including the first lensed quasar discovered, have smaller separations that can be explained in terms of galaxy-scale concentrations of baryonic matter. Although gravitationally lensed galaxies with large separations are known, quasars are more useful cosmological probes because of the simplicity of the resulting lens systems. Here we report the discovery of a lensed quasar, SDSS J1004 + 4112, which has a maximum separation between the components of 14.62 arcsec. Such a large separation means that the lensing object must be dominated by dark matter. Our results are fully consistent with theoretical expectations based on the cold-dark-matter model. 相似文献
855.
Lipophilic tea polyphenols (LTP) were prepared by catalytic esterifieation of green tea polyphenols (GRIP) with hexadeeanoyl chloride. A novel long-chain aeyl-derivative of epigalloeateehin-3-o-gallate(EGCG) was first isolated from purification of LTP by high-speed eountereurrent ehromatography (HSCCC)using a solvent system composed of n-hexane-ethyl acetate-methanol-water ( 1 : 1 : 1 : 1, v/v) . The moleeularstructure of the acyl-derivative, Epigallocatechin-3-O-gallate-4‘-O-hexadeeanate , was elucidated by meansof elemental analysis, IR, 1H-NMR and MS spectra. 相似文献
856.
计算机在处理蒙文信息过程中的一些问题的探讨 总被引:1,自引:1,他引:0
讨论了用计算机处理蒙文信息过程中遇到的一些问题,并提出了解决这些问题的可行性方案。 相似文献
857.
LEI Ming YAO Baoli CHEN Yi HAN Yong WANG Yingli MENKE Neimule ZHENG Yuan WANG Congmin FAN Meigong & CHEN Guofu . State Key Laboratory of Transient Optics Technology Xi抋n Institute of Optics Precision Mechanics Chinese Academy of Sciences Xi抋n China . Technical Institute of Physics Chemistry Chinese Academy of Sciences Beijing China Correspondence should be addressed to Yao Baoli 《科学通报(英文版)》2003,48(15):1548-1550
The optical storage characteristics of a new kind of organic photochromic material棗pyrrylfulgide were experimentally investigated in the established parallel optical data storage system. Using the pyrrylfulgide/PMMA film as a photon-mode recording medium, micro-images and encoded binary digital data were recorded, readout and erased in this parallel system. The storage density currently reaches 3?107 bit/cm2. The recorded information on the film can be kept for years in darkness at room temperature. 相似文献
858.
YUZhengquan FANBaoliang DAIYunping ZHENGMing MINHuiling WANGMeili WANGLili FEIJing LINing 《科学通报(英文版)》2003,48(21):2331-2335
Human lysozyme is a 130-aa (amino acid) alkaline polypeptide, and has both anti-bacterial and anti-viral properties which make it an important component of human natural immunity system. As a first step toward the ultimate goal of improving the anti-bacterial properties of bovine and ovine milk, a transgenic mouse that contains the genomic DNA sequence of the human lysozme gene has been generated for the first time. From 83 mice generated by microinjection, a total of 6 positive transgenic mice were identified by PCR and Southern blot. F1 mice positive for transgene in lines were also detected by PCR. This shows that transgene could be transmitted from founder transgenic mice to their offspring. Recombinant human lysozyme (rHlys) was found in the whey of 3 female positive transgenic mice by Western blot. The highest concentration of rHlys for transgenic mice was 0.2mg/mL. The antibacterial activity of the whey for transgenic mice was highly enhanced up to 0.4 times as much as that of human, while that of non-transgenic mouse was very low. Although the lysozyme activity of transgenic mice is still lower than that of human, the rHlys exhibits the same specific activity as that of human lysozyme. It provides a strong basis for further studies into the possible application of rHlys express in mammary gland. 相似文献
859.
Weimin ZHENGSchool of Economics Management Tsinghua University. Beijing China 《系统科学与系统工程学报(英文版)》2003,12(1):2-12
Universe, ecosystem, social system, etc. are evolving systems. The evolving processes of thesesystems have gradual small changes and rapid drastic changes with uncertainties under the constraintsof environment. Systems, as a whole, are evolving toward complexity, diversity and variety withfluctuations and jumps. New order emerges from "mutations". The evolution is bothchance-dependent and path-dependent. In this paper three basics: entropy, information and noise areemphasized with regard to system evolution which is a field that can give people wisdom to solvesystem problems with domain knowledge. 相似文献
860.
公路军事交通运输勤务综合演习项目GERT网络模型研究与分析 总被引:11,自引:0,他引:11
运用随机网络理论 ,构建了在现代高技术战争条件下 ,“红、兰”军双方激烈对抗时 ,公路军事交通运输勤务系统运行过程的 GERT网络模型 ,并举例求出了其解析解 .在此基础上 ,提出了演习 (或战争 )时 ,公路军事交通运输保障的“失败”概率与“转移”(战术、战役或战略转移 )概率的概念 ,并对其因素构成及其相互关系进行了剖析 . 相似文献