检索结果-南通市图书馆

Investigation on the potential barrier to internal rotation in molecules——Ab initio calculation and energy partition of the internal rotation barrier in complex molecule H_3.-BH_3

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Chemistry 1992年第5期10卷 385-389页

作者： ZHANG, Qi-Yuan YAN, Ji-Min institute of Chemistry, chinese {2. of Sciences, Beijing 100080 institute of Chemistry Chinese Academy of Sciences Beijing 100080

Based on the ab initio/6-3.Gcalculation, the potential barrier to internal rotation in mol-ecule HN--BHhas been studed by means of PD/LSF atomic charge model and Buckingham（exp--6-1）energy partition method. The results indicate that the order of the contributions of the componentsto the total energy barrier △E is |△V|（electrostatic） >|△V| （charge transfer）>|△V| （exchangerepulsion）>|△V| （dispersion）. For △Vthere are maxima at θ= 3.°and 90°, and a saddle atθ= 60°. There are good linear relationships for the total barrier △E, △Vand △Vwith cos3.respectively, and the same for the dipole moment from PD/LSF model (μ) and that from abinitio calculation (μ) vs. cos3. respectively.

关键词： Ab initio calculation and energy partition of the internal rotation barrier in complex molecule H3.-BH3

Bcl-2.cleavages at two adjacent sites by different caspases promote cisplatin-induced apoptosis

在线全文

学校读者我要写书评

暂无评论

Cell Research 2007年第5期17卷 441-448页

作者： Jianbei Zhu1 Ying Yang1 Jiarui Wu1,2. 1 Kev Laboratory of Systems Biology, institute of Biochemistry and Cell Biology, Shanghai institutes for Biological Sciences, {2. {3. of Sciences, 3.0 Yueyang Road, Shanghai 2.003., china 2.Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science & Technology of china, Hefei 2.3}02., china Key Laboratory of Systems Biology Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Shanghai China Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences University of Science & Technology of China Hefei China

The protein encoded by bcl-2.proto-oncogene plays an important role in the mitochondria-mediated apoptotic *** the general role of Bcl-2.is anti-apoptotic, previous work showed that Bcl-2.fragments cleaved by caspasescould promote apoptotic process. We report herein that Bcl-2.protein was cleaved to produce two fragments of around2.0}kDa in human hepatocarcinoma BEL-7404 cells or in Bcl-2.overexpressing CHO cells induced by cisplatin. Treat-ing cells with the general caspase inhibitor z-VAD-fmk blocked the induced cleavage of Bcl-2. Mutagenesis analysesshowed that Bcl-2.was cleaved by caspases at two adjacent recognition sites in the loop domain (YEWD3.↓AGD3.↓V),which could be inhibited by caspase-8 and -3.inhibitors, respectively. Overexpression of the carboxyl terminal 2.0}kDafragments increased the sensitivity of CHO cells to cisplatin-induced apoptosis. These results indicate that Bcl-2.can becleaved into two close fragments by different caspases during cisplatin-induced apoptosis, both of which contribute tothe acceleration of apoptotic process.

关键词： Bcl-2 apoptosis cisplatin caspase-3 caspase-8

Research on runoff forecast approaches to the Aksu River basin

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth Sciences 2007年第S1期 16-25页

作者： OUYANG RuLin1,2. CHENG WeiMing1, WANG WeiSheng3. JIANG Yan1, ZHANG YiChi1 & WANG YongQin4 1 State Key Laboratory of Resources and Environmental Information System, institute of Geographic Sciences and Natural Re-sources Research, {2. academy of Sciences, Beijing 100101,{3. 2.Department of Water Resources and Environment, Hohai University, Nanjing 2.0098,{3. 3.Xinjiang institute of Ecology and Geography, {2. academy of Sciences, ürümqi 83.011,{3. 4 Xinjiang Tarim River Basin Management Bureau, Korla 841000,{3.

The Aksu River (the international river between china and Kirghiz) has become the main water source for the Tarim River. It significantly influences the Tarim River's formation, development and evolution. Along with the western region development strategy and the Tarim River basin comprehensive devel-opment and implementation, the research is now focused on the Aksu River basin hydrologic charac-teristic and hydrologic forecast. Moreover, the Aksu River is representative of rivers supplied with gla-cier and snow melt in middle-high altitude arid district. As a result, the research on predicting the river flow of the Aksu River basin has theoretical and practical significance. In this paper, considering the limited hydrometeorological data for the Aksu River basin, we have constructed four hydrologic forecast approaches using the daily scale to simulate and forecast daily runoff of two big branches of the Aksu River basin. The four approaches are the upper air temperature and the daily runoff correlation method, AR(p) runoff forecast model, temperature and precipitation revised AR(p) model and the NAM rainfall-runoff model. After comparatively analyzing the simulation results of the four approaches, we discovered that the temperature and precipitation revised AR(p) model, which needs less hydrological and meteorological data and is more predictive, is suitable for the short-term runoff forecast of the Aksu River basin. This research not only offers a foundation for the Aksu River and Tarim Rivers' hydrologic forecast, flood prevention, control and the entire basin water collocation, but also provides the hydrologic forecast reference approach for other arid ungauged basins.

关键词： the Aksu River ungauged basins daily runoff forecast model

Investigation on the influence of atomic potentials on the above threshold ionization

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese physics B 2014年第5期23卷 238-243页

作者：田原野李苏宇魏珊珊郭福明曾思良陈基根杨玉军 institute of Atomic and Molecular physics Jilin University Data Center for high energy Density {2. Institute of Applied Physics and Computational Mathematics Science and Technology Computation physics Laboratory Institute of Applied Physics and Computational Mathematics Department of physics and Materials Engineering Taizhou University

We systematically investigate the influence of atomic potentials on the above-threshold ionization （ATI） spectra in one-dimensional （1D） cases and compare them with the three-dimensional （3.） case by numerically solving the time-dependent Schrrdinger equation. It is found that the direct ionization plateau and the rescattering plateau of the ATI spectrum in the 3. case can be well reproduced by the 1D ATI spectra calculated from the supersolid-core potential and the soft-core potential, respectively. By analyzing the factors that affect the yield of the ATI spectrum, we propose a modified-potential with which we can reproduce the overall 3. ATI spectrum. In addition, the influence of the incident laser intensities and frequencies on the ATI spectra calculated from the proposed modified potential is studied.

关键词： above threshold ionization model potential angular distribution of photoelectron

在线全文

学校读者我要写书评

暂无评论

基于裂解气质联用分析的生物质逐级热解研究

燃料化学学报 2010年第2期38卷 168-173页

作者：吴选民赵增立吴文强李海滨中国科学院广州能源研究所中国科学院可再生能源与天然气水合物重点实验室广东广州510640 中国科学院研究生院北京100049

为探究生物质快速热解反应历程,利用裂解气质联用仪对生物质进行逐级热解实验,考察在不同温度区间热解液体产物组分的分布规律。实验结果表明,生物质的化学组成和热解温度区间对热解液体产物都有重要影响。桉木在2.℃~400℃热解液体产... 详细信息

为探究生物质快速热解反应历程,利用裂解气质联用仪对生物质进行逐级热解实验,考察在不同温度区间热解液体产物组分的分布规律。实验结果表明,生物质的化学组成和热解温度区间对热解液体产物都有重要影响。桉木在2.℃~400℃热解液体产物较少,主要是吡喃和芳香类化合物,其中5,6-二氢-4-羟基-吡喃-2.酮相对峰面积随温度升高而降低;在450℃~500℃热解液体产物种类和产量均较多,主要以酮类和芳香类化合物为主。玉米芯热解规律和桉木的相似,但在2.℃~3.0℃主要以呋喃类化合物为主,主要热解液体产物是2.3.二氢-苯并呋喃和2.甲氧基-4-乙烯基苯酚,在400℃~450℃热解液体产物以酮类化合物为主。生物质主要化学组分在不同温度区间热解得到不同液体产物,对其进行选择性热解,能够有效实现生物质资源的综合利用。

关键词：生物质逐级热解裂解气质联用

Studies on the Construction Parameter of an Artificial Occluded Cell for In-situ Inspection of the Propagation Rate of Localized Corrosion

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2001年第3期17卷 355-358页

作者： Liangcai LEI, Fengping WANG, Yanmin GAO and Yuanlong DU State Key Lab for Corrosion and Protection, institute of Metal Research, chinese {2. of Sciences, Shenyang 110016,{3. To whom correspondence should be addressed Present address: Department of Dept. of Appl. Chem. Fushun Petroleum Inst. Fushun 113001 China

An artificial localized corrosion system is assembled and some parameters related to the localized corrosion in active dissolution state (i.e., non-passive state) have been studied. The results showed that the developed electrochemical system can satisfactorily imitate a naturally formed localized corrosion and the coupling current can indicate the maximum localized propagating rate. In this artificial system, the anodic dissolution reaction followed the auto-catalytic mechanism. The localized corrosion current density was dependent on the area ratio R of the cathode to the occluded anode. While R was equal to or more than 6, the coupling current reached at a maximum value and did not alter with the increase in R-value. Therefore, R=7 is chosen as one of these optimum parameters used in constructing the system, with which the biggest galvanic current might be obtained. In contrast, the thickness of the polymer filler separating the occluded anode area from the bulk electrolyte solution and the volume of the occluded anode area did not affect the corrosion current obviously. They might affect the response time to approach a steady state.

关键词： In Cell Studies on the Construction Parameter of an Artificial Occluded Cell for In-situ Inspection of the Propagation Rate of Localized Corrosion UNS

Mobility of elements during lamprophyre alteration and altered fluid characteristics in the Zhenyuan gold deposit

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1999年第S2期44卷 254-256页

作者： HUANG Zhilong, LlU Congqiang and XlAO Huayun Open Laboratory of Ore Deposit Geochemistry, institute of Geochemistry, chinese {2. of Sciences, Guiyang 550002.{3. Open Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

LAMPROPHYRES are one of the rock types which are easily subject to alteration. Alteration can not onlychange their texture and mineral assemblage, but also influence their geochemistry properties. The mostavailable data show that alteration will directly influence the content of Au in lamprophyre. For example,in the Superior area of Canada and the Yilgan area of Australia relatively fresh lamprophyres are bothlow in Au contents (3.9×10-9 and 1.7×10-9, respectively), but the contents of Au in altered lamprophyres from both areas are double increased (3.×10-9 and 2.×10-9 on average). Lamprophyres arewidely exposed in the Zhenyuan gold deposit, Yunnan Province and they are closely associated with goldmineralization both in space and in time. So the lamprophyres in the Zhenyuan gold deposit can be citedas the most typical example both at home and abroad. Lamprophyres in the mining district have undergonevarying-degree alteration and partly experienced mineralization. On the basis of the mass equilibrium e-

关键词： element mobility altered fluid lamprophyre Zhenyuan gold deposit.

The Electronic Structure of Molecular Ion [Mo(qdt)_3.^(2.)(qdp: quinoxaline-2.3.dithiolate)

在线全文

学校读者我要写书评

暂无评论

chinese Chemical Letters 1999年第6期10卷 503-504页

作者： Wen LI Jian Ping YE Chen Ho TUNG(institute of Photographic Chemistry. The chinese {2. of Sciences. Beijing 100101) institute of Photographic Chemistry Chinese Academy of Sciences Beijing 100101 China

The electronic structure of the molecular ion has been calculated by DV-Xα *** calculated nitrogen atomic charge is high in negative. The frontier molecular orbitals are mainly composed of Mo and S atomic valence orb... 详细信息

关键词： Molybdoenzymes electronic structure quantum chemistry

TEUPERNIN D: A CHLORINE-CONTAINING NEO-CLERODANE DITERPENE FROM TEUCRIUM PERNYI

在线全文

学校读者我要写书评

暂无评论

chinese Chemical Letters 1991年第11期2卷 845-846页

作者： Ning XIE~1. Zhi Da MIN~1, Shou Xun ZHAO~1. Yang LU~2.Qi Tai ZHENG~2.and Chun Shu WANG~2.1. Department of Phytochemistry, china Pharmaceutical University, Nanjing, 2.0009 2. institute of Materia Medica, {2. {3. of Medicinal Sciences, Beijing. 100050

A new chlorine-containing neo-clerodane diterpene, teupernin D, was isolated from the aerial parts of Teucrium pernyi. The structure for teupernin D was established as (12.) -15, 16-epoxy-8β-hydroxy-17-chloro-19-nor10α-neo-cleroda-4, 13.16), 14-triene-18,6β;2.,12.diolide on the basis of spectral evidence. The absolute configuration was established by CD spectrum and confirmed by X-ray crystallographic analysis.

关键词： NEO TEUPERNIN D A CHLORINE-CONTAINING NEO-CLERODANE DITERPENE FROM TEUCRIUM PERNYI