检索结果-南通市图书馆

行波管放大器中场极限环和混沌行为的阈值分析

在线全文

cnki会议

学校读者我要写书评

暂无评论

物理学报 2003年第8期52卷 1979-1983页

作者：郝建红丁武张治畴中国工程物理研究院研究生部北京应用物理与计算数学研究所北京100088

以场方程和电子运动方程为基础 ,分析了行波管放大器中辐射场演化过程中出现极限环振荡和混沌态的电流阈值 .结果表明 :在某些参数范围内 ,辐射场会出现这些非线性不稳定态 .相互作用区域越长 ,失谐量对阈值的影响越明显 .当器件工作在... 详细信息

以场方程和电子运动方程为基础 ,分析了行波管放大器中辐射场演化过程中出现极限环振荡和混沌态的电流阈值 .结果表明 :在某些参数范围内 ,辐射场会出现这些非线性不稳定态 .相互作用区域越长 ,失谐量对阈值的影响越明显 .当器件工作在非线性区域时 ,输出功率与电流、失谐量和相互作用区长度三个参数的关系变得紊乱无序 ,控制这三个参数在输出功率曲线的峰值点上 ,可在非线性区域获得较高的输出功率 .

关键词：行波管放大器辐射场演化过程极限环混沌行为阈值分析 TWT 微小器件

Multiple conformations of proteins in native state

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2002年第3期 3-7页

作者： SHENG Xiangrong and PAN Xianming(National Laboratory of Biomacromolecules, Institute of Biophysics, chinese academy of {2., {3., 100101, china) National Laboratory of Biomacromolecules Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China

Examples of protein sequences that can adopt multiple native states are recently accumulated. Characterization of the protein multiple conformations will have important implications for our understanding of the relationship between structure and function, and their folding kinetics. In present review, the experimental evidence for the existence of multiple conformations in the native state of proteins, the molecular basis and the biological significance of multiple conformations of proteins are focused.

关键词： protein folding multiple native conformations molecular basis biological significance.

Well-defined molecular structure and nanomaterials

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Well-defined molecular structure and nanomaterials

2.(nd) Spring Meeting of the International Society of Electrochemistry

作者： Li-Jun Wan Institute of Chemistry, chinese academy of {2., {3. 100080, china.

Nanoscience and nanotechnology is the creation and utilization of materials, devices, and systemsthrough the control of matter on the nanometer-scale. Its essence is the ability to work at theselevels to generate larger structures exhibiting novel physical, chemical, and biological propertiesand phenomena. The aim of nanoscience and nanotechnology is to learn to exploit theseproperties and efficiently manufacture and employ the structures. The control of matter onnanoscale has already played an important role in scientific disciplines as diverse as physics,

关键词： Well-defined molecular structure and nanomaterials

新载体pET-DB对带有His-tag的仓鼠二氢叶酸还原酶的高效表达与纯化

在线全文

cnki会议

学校读者我要写书评

暂无评论

生物化学与生物物理进展 2004年第7期31卷 655-658页

作者：朱志勇谭波张文河张洪杰北京师范大学生物化学与分子生物学系北京100875 中国科学院生物物理研究所北京100101

报道了带有His tag的仓鼠二氢叶酸还原酶基因的克隆和在DB序列增强下T7启动子调控该基因在大肠杆菌中的可溶性高效表达 ,SDS PAGE分析表明 ,带有His tag的仓鼠二氢叶酸还原酶的含量可占大肠杆菌细胞总蛋白质含量的 4 6 % .该酶的纯化可... 详细信息

报道了带有His tag的仓鼠二氢叶酸还原酶基因的克隆和在DB序列增强下T7启动子调控该基因在大肠杆菌中的可溶性高效表达 ,SDS PAGE分析表明 ,带有His tag的仓鼠二氢叶酸还原酶的含量可占大肠杆菌细胞总蛋白质含量的 4 6 % .该酶的纯化可用常规的金属络合树脂一步纯化至SDS PAGE一条带 ,经凝血酶切去His tag的仓鼠二氢叶酸还原酶与用等电聚焦法获得的无His tag的酶有相同的酶活性 .

关键词：蛋白质表达二氢叶酸还原酶 pET—DB载体 His—tag

Nondegenerative ML-sequences over ring Z/（2.）

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 1999年第17期 1557-1561页

作者： YANG Junhui and ZHAI Qibin Institute of Software , chinese academy of {2. , {3. 100080, china State Key Laboratory of Information Security , {3. 100080, china

The so-called quasi-period of an ML-sequence has been introduced. It is noted that an ML-sequence may degenerate in the sense that it has the quasi-period shorter than its period, and the problem of constructing the n... 详细信息

关键词： nondegenerate ML-sequence quasi-period.

Sausage Appearance Defect Inspection system based on Machine Vision

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Sausage Appearance Defect Inspection system based on Machine...

2.10 chinese Control and Decision Conference

作者： Shuai Chen~(1,2.,Yue Ma~1,Haibo Shi~1 1.Shenyang Institute of Automation chinese academy of Science,Shenyang,{2. 2.Graduate school of chinese academy of Science,beijing,{2.

＜正＞A real-time sausage appearance defect inspection system is presented in this *** general hardware and software structure is presented and a model method for sausage defect detection is *** inspection system give... 详细信息

关键词： machine vision automation visual inspection minimum enclosing rectangle

In vitro assay for human thyroid hormone receptor β agonist and antagonist effects of individual polychlorinated naphthalenes and Halowax mixtures

在线全文

cnki会议

学校读者我要写书评

暂无评论

chinese Science Bulletin 2011年第6期56卷 508-513页

作者： LI Na MA Mei WANG ZiJian SENTHIL KUMARAN Satyanarayanan State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Unit of Toxicology Bharathiar University Coimbatore 641046 India

Polychlorinated naphthalenes (PCNs) are dioxin-like environmental contaminants. There is growing concern over the endocrine-disrupting effects of PCNs, but very few studies have investigated the effect of PCNs on the thyroid system. This study used a yeast two-hybrid assay, which included the recombinant human thyroid receptor(TR)-β and reporter genes, to characterize the TRβ-disrupting effects of five individual PCN congeners, five PCN Halowax mixtures, and naphthalene. Their agonist and antagonist effects were studied in the absence and presence of 5×10-7 mol/L 3.3.,5-triiodo-L-thyronine, which induced submaximal β-galactosidase activity. Naphthalene, 1,2.3.4,5,6,7,8-octachloronaphthalene and all of the Halowax mixtures (Halowax 1000, 1001, 1013. 1014 and 1099) showed no agonist or antagonist activity on TRβ at the concentrations tested (up to 10-2.g/L). The lighter PCN congeners, namely 1-chloronaphthalene, 2.chloronaphthalene, 1,4-dichloronaphthalene and 1,2.3.4-tetrachloronaphthalene showed no agonist activity but showed significant antagonist activity on TRβ. The 2.% relative inhibitory concentrations of these PCNs were less than 9.13.× 10-3.g/L. Thus, bioaccumulation of these lighter PCN congeners may disrupt the thyroid hormone system and inhibit TR-mediated cellular responses. Studies in the future should investigate the possible associations between the presence PCNs and adverse health outcomes.

关键词：甲状腺激素受体多氯萘激动剂混合物拮抗剂测定体外拮抗活性

Crustal P-wave velocity structure in Lower Yangtze region:Reinterpretation of Fuliji-Fengxian deep seismic sounding profile

在线全文

学校读者我要写书评

暂无评论

Crustal P-wave velocity structure in Lower Yangtze region:Re...

中国科学院地质与地球物理研究所2.06学术年会

作者： BAI Zhiming~1 & WANG Chunyong~2.1.Institute of Geology and Geophysics,chinese academy of {2.,beijing 10002.,china 2.Institute of Geophysics,china Earthquake Administration,beijing 100081,china

The finite-difference inversion method and Rayinvr technique had been employed to interpret the wide-angle seismic reflection/refraction data of the Fuliji-Fengxian deep seismic sounding(DSS) profile in Lower Yangtze region,hence the velocity structure was acquired and conclusions were summarized as follows:(1) The velocity model along this profile can be divided into three large layers vertically(upper,middle and lower crusts) and six blocks laterally,and this velocity distribution agrees with the feature of stable platform.(2. The depth of Moho discontinuity is 3.-3. *** thickness of the upper crust is 10.5-13.0km,where the lateral velocity varies strongly,and the velocity increases to 6.2.kms at ***,the velocity distributions in the bottom layer of middle crust and lower crust have an apparent *** velocity in upper layer of middle crust,lower layer of middle crust,lower crust and uppermost mantle is 5.9-6.2.6.3.6.4,6.6-7.0 and 8.06-8.2. kms,respectively.(3. On two sides of the Tanlu fault belt(TFB),the mid-crustal velocity structure is quite different, nevertheless no apparent discrimination in velocity distribution and boundary topography exhibits in lower crust,hence it is inferred that the Jiashan segment of TFB had probably cut through whole crust in the Mesozoic,and the fault behaviour in lower crust had disappeared due to the low viscosity produced by the orogenic extension or crustal balance,while the fault features in the rigid middle-upper crust have been preserved up to the present.(4) The moderate earthquakes with Ms>5.0 nearby Zhenjiang are related to the deep faults extending into the lower crust,and the earthquakes were probably induced by the energy been transferred from mantle lithosphere to upper-mid crust along the deep faults,and aggregated at some preferable tectonic positions.

关键词： eastern china Fuliji -Fengxian DSS profile wide-angle seismic data velocity structure Tanlu fault belt earthquake

THE EXISTENCE OF CONNECTING ORBITS

在线全文

cnki会议

学校读者我要写书评

暂无评论

Annals of Differential Equations 2011年第4期27卷 505-508页

作者： Shuxiang Yu (Institute of Math.,chinese academy of {2.,{3. 100190)

In this paper,using the notion of an isolating block and Conley’s attractor theory,an existence criterion of trajectories connecting a pair of invariant sets of ordinary differential equations is given.

关键词： connecting orbits invariant sets isolating blocks repeller