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21.
ZHU Yabin ZHOU Yueliang LIU Zhen WANG Shufang CHEN Zhenghao U Huibin YANG Guozhen XlAO Ling Ren Hongtao JIAO Yulei Zheng Minghui 《中国科学G辑(英文版)》2004,47(2):165-172
The irreversibility field (Hirr) of Y-based superconductor is much higher than that of Bi-based superconductor. Y-based superconductor is capable of maintaining stable electrical currents in high magnetic field and electric field, so it is a better suited mate-rial for electric-current applications. Commonly, the Y-based tapes comprise a YBCO thick film deposited on a flexible substrate, typically with an intermediate buffer layer, and an overcoat of noble metal. In this process, the interm… 相似文献
22.
光突发交换的交换控制策略和光缓存配置 总被引:4,自引:2,他引:2
光突发交换是面向下一代互联网的光交换模式.讨论了异步光突发交换系统的交换控制策略以及相应光缓存的优化配置策略.除了传统预约模式的交换策略,还研究了非预约和改进型预约模式,它们的性能评估由计算机仿真给出.结果表明:在条件相当情况下,改进型预约模式具有最低的丢包率.同时光缓存的配置对上述几类交换控制策略的性能都有很大影响,仿真结果指出:光缓存的粒度对系统性能具有重要影响,所讨论的几类交换模式都存在最佳时延粒度,研究结果对光交换矩阵的设计有指导意义. 相似文献
23.
Pengbo Jiang Tiexin Cheng Yan Liu Xianghao Cui Yingli Bi Kaiji Zhen 《Reaction Kinetics and Catalysis Letters》2004,82(1):49-56
The novel phase transfer catalysts S-8 [4-(dimethyloctylammonium) propansultan] and DB-X [1,4-bis(triethylmethylammonium)benzene dibromide] were synthesized and employed for high conversion synthesis of dichlorocyclopropane from various olefins.This revised version was published online in December 2005 with corrections to the Cover Date. 相似文献
24.
ZhenFengZHANG 《数学学报(英文版)》2005,21(1):155-168
In this paper, we extend a classical result of Hua to arithmetic progressions with large moduli. The result implies the Linnik Theorem on the least prime in an arithmetic progression. 相似文献
25.
YunXiaWANG LinJIA ZhenSHI 《中国化学快报》2003,14(6):561-564
The addition-hydrolysis reaction of benzimidazolium salt with some mono- and bifunctional amine nucleophiles is reported,and a novel method of biomimetic synthesis for formamides and heterocycle compounds is provided. 相似文献
26.
Random copolymers of poly{(methacrylamide)-co-(vinyl trimethoxysilane)} and poly{(methacrylic acid)-co-(vinyl trimethoxysilane)} were synthesized via a free radical polymerization reaction. Acid catalyzed sol-gel process of tetraethylorthosilicate (TEOS) with aforementioned polymers in the presence of methyl xanthine class of alkaloid like caffeine resulted in the formation of highly transparent monoliths. Solvent extraction of the template leaves behind the recognition sites intact with high selectivity towards the print molecule. The ionic and non-specific adsorptions, which are considered to be the main disadvantages of the molecularly imprinted polymers (MIP), are prevented to a considerable extent by the end capping of surface silanol groups. The template binding efficiencies of MIP were determined by HPLC analysis. 相似文献
27.
Based on the complexation between proteins and Cu(II) coupled with the time-resolved chemiluminescence (CL) technique, a highly sensitive and quantitative assay for measuring proteins in solution is described. The complexes of proteins with Cu(II) have a strongly catalytic effect on the luminol-H2O2 CL reaction. Because the CL emission produced by the complexes is much more long-lived than that by Cu(II), the CL signals originating from proteins can be easily identified and measured with a time-resolved technique. On this basis, bovine albumin fraction V (BAF V) can be quantitatively determined in the range of 0.01 - 5.0 microg/ml with a detection limit of 5.8 ng/ml. The results show that the proposed assay exhibits a small variation in the response values for the same amount of different proteins, as compared to the Lowry as well as Bradford assays. The CL assay has also been studied for the detection of immobilized proteins. 相似文献
28.
Fe2(CO)6(μ-S2) was used as a single source precursor in attempt to produce FeS film via MOCVD. Pyrolysis of Fe2(CO)6(μ-S2) at temperature below 500℃ produced Fe1-xS or Fe7S8 powder as indicated by its powder X-ray spectra. At 750 ℃, polycrystalline FeS powder was obtained. In film deposition, polycrystalline Fe1-xS or Fe7Ss films were obtained on Si(100) and Ag/Si(100) substrates below 500 ℃. SEM micrographs showed the film on Si(100) substrate containing whisker like grains. However, pillar like grains were obtained on Ag/Si(100) substrate.Deposition rates are also different for different substrates as evaluated by the thickness of the films, which were obtained by SEM micrographs of the cross section of the films. At 750℃, similar polycrystalline Fe1-xS or Fe7S8 film was obtained. 相似文献
29.
Qing An WU Zhen Yuan XU Mei ZHENG Dan Qian XU Jun XU Yin Chu SHENCollege of Chemical Engineering Materials Zhejiang University of Technology Hangzhou 《中国化学快报》2004,(7)
Six new 13-O-acylavermectin Bl aglycones(3-8) were synthesized from avermectin B1 aglycone and their bioactivities were evaluated against Spodoptera exigua, Spodoptera eridania, Tetranychus urticae and Aphis fabae. 相似文献
30.
B. Pignataro L. Chi S. Gao B. Anczykowski C. Niemeyer M. Adler H. Fuchs 《Applied Physics A: Materials Science & Processing》2002,74(3):447-452
Self-assembled oligomeric nanostructures consisting of bisbiotinylated DNA fragments connected by the protein streptavidin
(STV) are studied by dynamic scanning force microscopy (SFM) operating in air. A comparison of the images taken in repulsive
and attractive regimes is systematically made on DNA and STV structures. Stable and reproducible SFM images are obtained in
the attractive regime by using a special feedback circuit, called Q-control. On the other hand, when SFM is operating in the
repulsive regime, deformation of the structures that reduce the resolution and the image quality are clearly observable. The
heights of both DNA and STV have been measured as a function of the tip/molecule interaction forces. This study offers the
possibility to suggest a different mechanical behavior of DNA with respect to STV.
Received: 24 July 2001 / Accepted: 3 December 2001 / Published online: 4 March 2002 相似文献