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111.
Lightning activity on the central Tibetan Plateau and its response to convective available potential energy 总被引:6,自引:0,他引:6
Lightning flash activities on the central Tibetan Plateau have been studied by using the satellite-based Lightning Imaging Sensor(LIS)database from January 1998 to July 2002.The lightning activity shows a clear diurnal variation on the central Plateau.The peak lightning activity appears at about 17:00 which is 3 h earlier than that in Jingxhou,Hubei in the same latitude belt nearby,indicating that the lightning activity is a sensitive indicator of solar heating on the Plateau.The lightning discharge is weaker on the Plateau than Jingzhou.Hubei and other low-altitude continental regions because of the lower convective available potential energy(CAPE)on the Plateau.The CAPE on the Plateau is 12 times lower than that in Jingzhou,Hubei,and 20 times lower than that in the sea-level region,such as Guangzhou and Florida.However,the sensitivity of lightning activity to CAPE changes on the Plateau is up to 30 times more sensitive than other prominent low-altitude regions. 相似文献
112.
on the human tumor cell growth MA Yewei ZHOU Xiaoshan QIAN Xinlai ZHAO Qingzheng YANG Jun GAO Xin LI Yanchun LIU Yuying & WANG Zheng . Cancer Institute Peking Union Medical College Chinese Acad-emy of Medical Sciences Beijing China . Beijing Institute of Blood Transfusion Medicine Beijing China 《科学通报(英文版)》2003,(7)
The human adenovirus type 5 E1A, a tumor- suppressor gene[1], codes for two major related proteins of 243 amino acids (12S) and 289 amino acids (13S) by al-ternative splicing in two exons[2]. Studies have been shown that E1A can regulate expression of many genes and cell cycle[3]. Both in vitro and in vivo experiments indicated that E1A could induce tumor cells differentia-tion, convert tumor cells into an epithelial phenotype, in-hibit tumor cell growth and metastasis and strongly en-ha… 相似文献
113.
HE Chenxia FENG Dengmin WU Wenjun DING Youfa CHEN Li CHEN Haoming YAO Jihua SHEN Qi LU Daru & XUE Jinglun . State Key Laboratory of Genetic Engineering Institute of Genetics School of Life Sciences Fudan University Shanghai China . Changhai Hospital The Second Military Medical University Shang-hai China . Hospital of Lishui Zhejiang China Correspondence should be addressed to Xue Jinglun 《科学通报(英文版)》2003,48(8)
The transfection of plasmid DNA into mammalian cells is an indispensable tool in the study of gene transfer and gene function. Since the original report in 1990 on the successful expression of a reporter gene in muscle[1], plasmid DNA injection has been widely used to mediate gene transfer study. As a gene transfer vector, naked DNA has many obvious advantages. It is easy and cheap to be prepared and more safe after transfection. But the plasmid mediated gene expression is low because of t… 相似文献
114.
ZHANG Xinbao D. E. Walling FENG Mingyi & WEN Anbang . Chengdu Institute of Mountain Hazards Environment Chinese Academy of Sciences 《科学通报(英文版)》2003,48(8):813-818
Throughout the past decade, the potential for using nuclear weapon-produced 137Cs ( half-life 30.2 a) fallout to quantify soil erosion rates on both cultivated and uncul- tivated lands for medium-term timescales (≈ 40 a) has been successfully demonstrated in a wide range of envi- ronments in different regions of the world[1—6]. Because in difficulties of distinguishing Chernobyl-derived compo- nent from total 137Cs input in many parts of Europe, and in measuring low activity samples of… 相似文献
115.
LU Anhuai GAO Xiang QIN Shan & WANG ChangqiuDepartment of Geology Peking University Beijing . China Correspondence should be addressed to Lu Anhuai 《科学通报(英文版)》2003,48(9):920-923
The Xiangtan manganese deposit (XTM) used to be considered a supergene oxide manganese ore in South China. We reported a new identification of the naturally outcropping cryptomelane by examining the physical, chemical and structural features of the XTM supergene oxide manganese ore. The MnO2 content was over 90%, K2O more than 3%, and water from 2.2%-3.1% which is similar to one in zeolite. The cell parameters of the cryptomelane were given as a0 = 0.9974 nm, b0 = 0.2863 nm, c0 = 0.9693 nm and β= 91.47°. There was a larger pseduotetragonal tunnel in the natural cryptomelane that was formed by [MnO6] octahedral double chains with aperture of 0.462×0.466 nm2, filled with K cations resulting in some Mn3+ substituting for Mn4+ to balance the negative charges of structure. The finding is important not only for prospecting manganese resources in South China, but also in application of octahedral molecular sieve of natural cryptomelane as that developed in the tetragonal molecular sieve of natural zeolite o 相似文献
116.
Let B_n be the unit ball of C~n and φ= (φ_1,…,φ_n) a holomorphic self-map of B_n. The main purpose of this paper is todiscuss the boundedness and compactness of composition operator C_φ between p-Bloch space β~p(B_n) and q-Bloch space β~p(B_n), where p≥0 and q≥0. 相似文献
117.
Two-pyroxene granulite and clinopyroxene granulite xenoliths have been recently discovered in the Late Paleogene toNeogene volcanic rocks (with ages in the range of 4.27~44.60 Ma) that outcropped in Hoh Xil, central Tibetan plateau. Based on theelectron microprobe analysis data, the xenoliths provide constraints for the formation equilibrium temperatures of the two-pyroxene gran-ulite being about 783 to 818℃ as determined by two-pyroxene thermometry and the forming pressure of the clinopyroxene granulite beingabout 0.845 to 0.858 GPa that is equivalent to 27.9~28.3 km depth respectively. It indicates that these granulite xenoliths represent thesamples from the middle part of the thickened Tibetan crust. This discovery is important and significant to making further discussion onthe component and thermal regime of the deep crust of the Tibetan plateau. 相似文献
118.
泰国木薯淀粉特性研究 总被引:5,自引:1,他引:5
木薯是热带地区碳水化合物的主要来源.木薯根的化学组成,淀粉含量,淀粉质量和淀粉性质常常决定木薯作为食品和工业用的价值.对广泛种植在泰国的2个木薯品种Kasetsart50(KU50)和Rayong5(R5)块根的化学组成、淀粉质量和淀粉性质分析结果表明:KU50比R5品种具有高的淀粉含量,高的氢氰酸含量和高的灰分含量.2个品种淀粉粒大小和直链淀粉含量并没有显著的差异.在85℃下KU50比R5具有高的膨润度.差示扫描量热仪测定的热力学特征为:KU50具有高的糊化起始温度、糊化结束温度、糊化峰值温度和热函.2个品种的淀粉粘度曲线差异较小.由此得出:从提取淀粉效率来说,KU50优于R5;作为饲料加工业,R5的饲料品质优于KU50;对于淀粉深加工业,因KU50和R5具有不同的热力学性质和粘度性质,因而根据加工产品的不同而具有不同的优缺点. 相似文献
119.
Design and application of 60mer oligonucleotide microarray in SARS coronavirus detection 总被引:6,自引:0,他引:6
SHI Rong MA Wenli WU Qinghua ZHANG Bao SONG Yanbin GUO Qiuye XIAO Weiwei WANG Yan & ZHENG Wenling . Institute of Molecular Biology First Military Medical University Guangzhou China . Department of Medical Research Guangzhou Liu Hua Qiao Hospital Guangzhou China Correspondence should be addressed to Ma Wenli 《科学通报(英文版)》2003,48(12):1165-1169
In April 2003, a novel coronavirus[1,2] which was associated with cases of Severe Acute Respiratory Syn-drome (SARS) was first isolated and sequenced in Canada. The genome of SARS coronavirus (SARS-CoV) is 29727[3] nucleotides in length and has 11 known open reading frames (ORFs). Although the genome organiza-tion of this virus is similar to that of other coronaviruses, phylogenetic analyses and sequence alignment show that SARS-CoV is not closely related to any of the previously ch… 相似文献
120.
Do multiple cycles of aeolian deposit-pedogenesis exist in the reticulate red clay sections in southern China? 总被引:4,自引:0,他引:4
HU Xuefeng CHENG Tianfan & WU Hexin Department of Environmental Science Engineering Shanghai Uni-versity Shanghai China Correspondence should be addressed to Hu Xuefeng 《科学通报(英文版)》2003,48(12):1251-1258
Since the Quaternary scientists successfully dis-closed the paleoclimatic significance of the loess-paleo- sol sequence in the Loess Plateau, Northwest China, the loess-paleosol sequence has become well-known terres-trial materials revealing the multiple cyclic changes of Quaternary climates. As a carrier of paleoenvironmental information, it could compare beauty with the deep ocean deposit[8]. In recent years, however, the researchers began to put their sights to southern China. They try t… 相似文献