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Observation of contrast variations of a copper(Ⅱ)complex by scanning tunneling microscopy

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Chinese Science Bulletin 2003年第6期48卷 531-534页

作者： WANG Zhigang, ZENG Qingdao, WANG Chen, ZHOU Chunqing, WAN Lijun & BAI Chunli The Center for molecular sciences, institute of Chemistry, Chinese Academy of sciences, Beijing 100080, china The Center for molecular sciences Institute of Chemistry Chinese Academy of Sciences Beijing China

This report presents experimental observations of dramatic variations in STM images of bis [1,3- di(p-n-tetradecyloxyphenyl)propane-1,3-dionato] copper(Ⅱ) (abbreviated to C14O-Cu) physisorbed on HOPG as the bias voltage is changed. Several representative image patterns were obtained for the rich changes of the internal contrast of the molecule. Submolecular features of the molecular cores and the interdigitated alkyl parts are clearly visible.

关键词：扫描隧道显微镜铜配合物实验观察对比度变化 STM图像吸附物

Capillary Electrophoretic Separation of Proteins under the Control of Radial Electric Field

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Chinese Chemical Letters 1999年第9期10卷 777-780页

作者： Yi CHEN Ying ZHU(Center for molecular sciences. institute of Chemistry.Chinese Academy of sciences. Beijing 100080) Chinese Acad Sci Ctr Mol Sci Inst Chem Beijing 100080 Peoples R China

Separation of basic proteins was performed using a homemade field-modulated capillary electrophoresis system. The resolution. elution and even wall adsorption can be regulated by ad-lusting the radial rather than axia... 详细信息

关键词： capillary electrophoresis protein separation radial electric field control

Fluorescence dynamics of interactions between polyamide PyPyPyβDp and DNA

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Science china Chemistry 2006年第1期49卷 75-80页

作者： ZHANG Huijuan1,2, WANG Jin3, WU Yishi1, YUAN Gu3, AI Xicheng1, WANG Li4 & ZHANG Jianping1 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species, institute of Chemistry, Chinese Academy of sciences, Beijing 100080, china 2. School of Life Science and Technology, Beijing institute of Technology, Beijing 100081, china 3. College of Chemistry and molecular Engineering, Peking University, Beijing 100080, china 4. Center for Condensed Matter Physics, institute of Physics, Chinese Academy of sciences, Beijing 100080, china Correspondence should be addressed to Ai Xicheng and Zhang Jianping 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China 2. School of Life Science and Technology Beijing Institute of Technology Beijing 100081 China 3. College of Chemistry and molecular Engineering Peking University Beijing 100080 China 4. Center for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China

The photophysical properties of the polyamide PyPyPyβDp (PPP) were investigated by means of steady-state absorption and fluorescence spectroscopies, as well as time-resolved fluo-rescence spectroscopy. It was found that the excited-state properties of PPP are very sensitive to solvents. In TKMC buffer PPP exhibited weak fluorescence with a decay time constant of 16 ps, while with the decrease of the solvent polarity PPP showed the blue-shifted peak position, increased inten-sity and lengthened life-time for its fluorescence behavior. In the presence of calf thymus DNA, it was observed that the fluorescence intensity was enhanced and the fluorescence lifetime increased from 16 to 32 ps for PPP, which verified that PPP bound into the minor groove of DNA duplex.

关键词： polyamide (PPP), calf thymus DNA (ctDNA), time-resolved fluorescence spectroscopy, recognition dynamics.

RHEOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

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Chinese Journal of Polymer Science 2001年第5期19卷 471-476页

作者： Zhen-zhong Yang Yuan-ze Xu De-lu Zhao State Key Laboratory of Polymer Physics & Chemistry, Center for molecular Science institute of Chemistry, Chinese Academy of sciences, Beijing 100080 china Chinese Acad Sci Inst Chem State Key Lab Polymer Phys & Chem Ctr Mol Sci Beijing 100080 Peoples R China

The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique. Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.

关键词： epoxy resin waterborne dispersion rheological behavior cluster-cluster aggregation percolation transition

Whole fossil plants of Ephedra and their implications on the morphology,ecology and evolution of Ephedraceae (Gnetales)

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Chinese Science Bulletin 2010年第15期55卷 1511-1519页

作者： WANG Xin 1,2 & ZHENG ShaoLin 3 1 Nanjing institute of Geology and Palaeontology,Chinese Academy of sciences,Nanjing 210008,china 2 Fairy Lake Botanical Garden,Shenzhen 518004,china 3 Shenyang institute of Geology and Mineral Resources,Shenyang 110034,china Nanjing institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China Fairy Lake Botanical Garden Shenzhen 518004 China Shenyang institute of Geology and Mineral Resources Shenyang 110034 China

Although there are many reports of fossil Ephedraceae,whole plant fossil record remains *** to a lack of trust on partially preserved fossil materials,scholars working on molecular clock proposed a recent origin of Ephedra and cast doubt on the earlier origin time of *** better the understanding on this interesting group,here we report whole plants of Ephedra hongtaoi ***.(Ephedraceae,Gnetales) from the Yixian Formation (Early Cretaceous) in western Liaoning,*** whole plants of Ephedra demonstrate clearly the characters of Ephedra,including shrubby growth habit,decussate branching pattern,and terminal ovuliferous unit with micropylar *** whole-plant preservation of the fossils provides more convincing fossil evidence of Early Cretaceous Ephedra,helps to resolve the controversy over the origin time of Ephedra,and sheds light on the whole plant morphology,growth habit,ecology and evolution of Ephedraceae.

关键词：化石植物生态学麻黄形态学进化材料保存早白垩世生长习性

Plantlet regeneration from mature zygotic embryos andembryonic explants of masson pine (Pinus massoniana Lamb.)

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Cell Research 1994年第2期4卷 155-162页

作者： HUANG JIANQIU ZHIMING WEI WEI ZHOU ZHIHONG XU.(National laboratory of Plant molecular Genetics, Shanghai institute of Plant Physiology, academia sinica, Shanghai 200032,china) National laboratory of Plant molecular Genetics Shanghai Institute of Plant Physiology Academia Sinica Shanghai China

Excised zygotic embryos, cotyledons and hypocotyls of juvenile seedlings of masson pine were grown on DCR medium supplemented with several concentrations of various plant phytohormones. BA (1.0 mg/ L) in combination with NAA (0.05 mg/L)in DCR medium was found to increase the formation of adventitious buds from mature zygotic embryos, but most of them were formed at the tips of embryonic cotyledons. Adventitious buds were obtained from cotyledons and hypocotyls from juvenile seedlings when they were cultured on DCR medium containing BA 3-5 mg/L and NAA 0.1-0.2 mg/L. Elongation of buds were observed on hormone-free DCR medium with or without activated charcoal (0.5%). Root initiation was achieved with full or half strength DCR inedium supplemented with IBA 1.0 mg/L and NAA 0.25-0.5 mg/L. Approximately 11-20 axillary buds formed on each explant when juvenile seedling explants were treated (3-20h) with BA 50-100 mg/L, followed by transfer to hormone-free DCR medium. The maximum number of shoots obtained per explant within six months was 33.

关键词： Pinus massoniana Lamb. DCR medium mature zygotic embryos embryonic explants plantlet regeneration

MODELING METHOD OF LOOP FOR PROTEIN ENGINEERING

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生物数学学报 1995年第1期10卷 1-13页

作者： Feng Zukang Ding Dafu(Shanghai institute of Biochemistry academia sinica 200031) 中科院上海生物化学所上海

A molecular modeling scheme using distance-based database search associated with contact potential analysis is proposed for modeling loop region of *** procedure has been proof of reliability through modeling 50 loop regions in globins, serine proteinases,calcium-binding proteins and *** is shown that 86％（43 out of 50）of the test cases are well modeled and only 14％（7 out of 50） can not be well modeled(main-chain Ca－atoms root－mean－square（r.m.s） deviations greater than l.0A).It is demonstrated that the scheme can be used to model loop regions for protein engineering．

关键词： Loop molecular modeling contact potential

Brownian ratchets driven by flashing noise strength

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Chinese Science Bulletin 1999年第21期44卷 1956-1961页

作者： ZHAO Tongjun, ZHAN Yong, ZHUO Yizhong and WU XizhenDepartment of Applied Mathematics and Physics , Hebei University of Technology , Tianjin 300130, china china institute of atomic Energy, Beijing 102413, china institute of Theoretical Physics, Chinese Academy of sciences , Beijing 100080, china Corresponding author Dept. of Appl. Math. and Physics Hebei University of Technology Tianjin 300130 China china institute of atomic Energy Beijing 102413 China institute of Theoretical Physics Chinese Academy of Sciences Beijing 100080 China

The stochastic transport driven by flashing multi-noise sources in a ratchet is studied. The stationary current versus the noise strength and the colored noise correlated time T is obtained . At a fixed flip rate and strength of the colored noises, the novel phenomenon of the current reversal occurs as T reaches a certain value. More than one reversal point exists when

关键词： flashing force ratchet current reversal Langevian equation.

TRANSIENT EFFECT OF A BOGER FLUID FLOWING AROUND A CONFINED CYLINDER

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Chinese Journal of Polymer Science 2001年第4期19卷 377-384页

作者： Xian-feng Li Huai-tian Bu De-lu Zhao State Key Laboratory of Polymer Physics and Chemistry Center for molecular Science,institute of Chemistry, Chinese Academy of sciences, Beijing 100080, china Chinese Acad Sci Inst Chem Ctr Mol Sci State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China

This paper is concerned with the numerical simulation of the transient effect of an inertialess Boger flow past a confined circular cylinder and the comparison of predictions with particle image velocimetry (PIV) measurements given by Shiang et al.. Dynamic simulation based on the Oldroyd-B constitutive model was carried out using a Lagrangian-Eulerian algorithm. The evolution of velocity field was obtained for the flow at two Deborah (De) numbers, i.e. De = 1.2 and 3.0. At low De, the flow reached steady state rapidly, and showed a symmetric flow regime. However, at high De, the time required to reach steady flow behind the cylinder increased significantly, and the distribution of the velocity field appears to be asymmetric with respect to the stagnation line. Fairly good agreement between the numerical results and the experimental observations is reported. It can be concluded that both the experimental measurements and the present simulations indicate that the elasticity of the polymeric flow strongly affect the flow regime of viscoelastic flow around a confined cylinder.

关键词： transient effect flow around a cylinder Lagrangian-Eulerian algorithm Oldroyd-B model