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891.
892.
QIN Xiaomei HONG Ming ZHANG Gongmu MAI Wenjie LI Fengying YU Richeng LIU Jing & JIN Changqing . Institute of Physics Chinese Academy of Sciences Beijing China . Beijing High Pressure Research Center Beijing China . Institute of High Energy Physics Chinese Academy of Sciences Beijing China Correspondence should be addressed to Jin Changqing 《科学通报(英文版)》2003,48(12):1201-1203
Since the discovery of high temperature supercon-ductivity by Bednorz et al. in 1986[1], many series of cu- prate superconductors have been synthesized. Critical temperature has been improved continuously. But no verdict has been given upon what mechanism causes su- perconductivity. CaCuO2 conductive layers are the parent structure of the high Tc cuprate superconductors, such as Cu-12 (n-1)n[2], Tl-12(n-1)n[3] and Hg-12(n-1)n[4,5] super- conductor families. In 1988, infinite-layer (Ca0.86S… 相似文献
893.
Hydrogen storage of aligned multi-walled carbon nanotubes (a-MWNTs),non-aligned MWNTs(n-MWNTs) and graphite electrodes are studied by the electro-chemical measurements .The electrodes are prepared by mixing carbon nanotubes (CNTs) copper powder and ptfe binder in a weight ratio of 1:5:3 and compressing the mixture into porous nickel collector,The results show that the electrochemical hydrogen storage capacity of the a-MWNT electrode is up to 1625 mAh/g corresponding to a high hydrogen storage of 5.7 wt% ,which is 10 times that of graphite electrode and is 13 times that of n-MWNT electrode, suggesting that a-MWNTs are promising materials for electrochemical hydrogen storage. 相似文献
894.
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
895.
896.
Tat-specific cytotoxic T lymphocytes select for SIV escape variants during resolution of primary viraemia 总被引:55,自引:0,他引:55
Allen TM O'Connor DH Jing P Dzuris JL Mothé BR Vogel TU Dunphy E Liebl ME Emerson C Wilson N Kunstman KJ Wang X Allison DB Hughes AL Desrosiers RC Altman JD Wolinsky SM Sette A Watkins DI 《Nature》2000,407(6802):386-390
Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections are characterized by early peaks of viraemia that decline as strong cellular immune responses develop. Although it has been shown that virus-specific CD8-positive cytotoxic T lymphocytes (CTLs) exert selective pressure during HIV and SIV infection, the data have been controversial. Here we show that Tat-specific CD8-positive T-lymphocyte responses select for new viral escape variants during the acute phase of infection. We sequenced the entire virus immediately after the acute phase, and found that amino-acid replacements accumulated primarily in Tat CTL epitopes. This implies that Tat-specific CTLs may be significantly involved in controlling wild-type virus replication, and suggests that responses against viral proteins that are expressed early during the viral life cycle might be attractive targets for HIV vaccine development. 相似文献
897.
898.
暗管排降对小麦养 分、干物质、籽粒产量及品质的影响 总被引:1,自引:0,他引:1
着重探讨了南方不同生态类型圩区农田埋设塑料暗管对小麦地上部分矿质营养吸收、干物质累积和分配、产量及品质的影响。试验结果表明:农田埋设塑料暗管排水能显著提高麦株地上部分对N、P,K矿质营养元素的吸收,促进小麦各生育期尤其是拔节孕穗期地上部分干物质累积,小麦增产幅度达到20.3% ̄53.3%,并能提高籽粒蛋白质和氨基酸含量,改善小麦籽粒的品质。 相似文献
899.
从现代排球立体进攻战术的演变与发展入手,阐述了立体进攻战术的主要特点,提出了培养与实施立体进攻战术的主要方法。 相似文献
900.
通过对小杂粮概念和分类的研究和阐述,分析了小杂粮在国内外的开发利用前景,并结合山西省北部地区的实际情况,介绍了几种小杂粮作物的高产机械化栽培技术。 相似文献