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Ab-initio molecular dynamics simulation on nano-system under external pressure

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Science china Mathematics 2004年第Z1期47卷 92-100页

作者： Jl Min, SUN Deyan & GONG XingaoSurface Physics laboratory and Department of Physics, Fudan University, Shanghai 2.0433, china {2. of Solid State Physics, chinese academy of sciences, Hefei 2.0031, china Interdisciplary Center for Theoretical studies, chinese academy of sciences, beijing 100080, china Surface Physics laboratory and Department of Physics Fudan University Shanghai China institute of Solid State Physics Chinese Academy of Sciences Hefei China Interdisciplary Center for Theoretical studies Chinese Academy of Sciences Beijing China

A new constant-pressure molecular dynamics (MD) method is developed to simulate the dynamic behavior and structure transition of finite system under external pressure. In this method, no artificial parameter is introduced and the computation overheads are very small. As an application, a hard-soft transition of single wall carbon nanotube (SWCNT) under external pressure is found, which is in agreement with the experiments.

关键词： phase transition, simulation, nano-particles

Kinetics of Nonisothermal and Isothermal Crystallization of Metallocene Polyethylene

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chinese Chemical Letters 1999年第2期10卷 175-178页

作者： Yu Ying LI Ji Jun ZENG Jia Song HE(State Key laboratory of Engineering Plastics, institute of chemistry,The{2.. beijing 100080) State Key Lab. of Eng. Plastics Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

The kinetics of nonisothermal and isothermal crystallization of metallocene catalyzed and conventional polyethylenes has been studied by differential scanning calorimetry. Using Avrami equation, Ozawa theory and Mo Zhishen method, the experimental data have been analyzed. It is shown that metallocene polyethylene possesses a higher rate of crystallization due to a higher stereoregularity of its molecular chains. Moreover, they have different nonisothermal crystallization mechanisms and identical isothermal crystallization mechanisms.

关键词： metallocene polyethylene nonisothermal crystallization isothermal crystallization

Oxygen pressure dependent electro-resistance in La_(0.9)Sr_(0.1)MnO_3 thin films grown by laser molecular beam epitaxy

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Science china(Physics,Mechanics & Astronomy) 2008年第3期51卷 232-236页

作者： OUYANG SiHua1,2.WANG ChunChang2.LIU GuoZhen2.HE Meng2. JIN KuiJuan2.DANG ZhiMin1 & L HuiBin2. College of Materials Science and Engineering,beijing University of Chemical Technology,beijing 10002.,{2. 2.beijing National laboratory for Condensed Matter Physics,institute of Physics,chinese academy of sciences,beijing 100080,{2. College of Materials Science and Engineering Beijing University of Chemical Technology Beijing China beijing National laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing China

We report here studies on the influence of oxygen pressure on the electroresis-tance behavior of La0.9Sr0.1MnO3 thin films fabricated by laser molecular beam epi-taxy. It was found that the film deposited at lower oxygen pressure shows larger c-axis parameter,higher resistance,and more distinct electroresistance. These results reveal that the electroresistance of manganite thin films can be tuned by the conditions of film fabrication.

关键词： La0.9Sr0.1MnO3 thin film electroresistance effect laser molecular beam epitaxy

STRESS-INDUCED CRYSTALLIZATION OF POLYURETHANE/MONTMORILLONITE NANOCOMPOSITE

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chinese Journal of Polymer Science 2002年第5期20卷 481-483页

作者： Xin-hua Dai Xiang-dong Luo Qun Gu Xiao-li Zhang De-yan Shen Liang-he Shi Jian Xu State Key laboratory of Polymer Physics and Chemiscy Center for molecular Science,{2.,chinese academy of sciences, beijing 100080, china Center for molecular Science Institute of Chemistry Chinese Academy of Sciences State Key Laboratory of Polymer Physics and Chemistry 北京 100080

Exfoliated polyurethane/montmorillonite nanocomposites with both high elongation at break and high tensilestrength were studied by dynamic-infrared spectroscopy (dynamic-IR). The results show that crystallization indu... 详细信息

关键词： PU/montmorillonite nanocomposite dynamic-IR crystallization

Paeonia rotundiloba(***)***:A new status in tree peonies(Paeoniaceae)

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Journal of Systematics and Evolution 2011年第5期49卷 464-467页

作者： De-Yuan HONG(State Key laboratory of Systematic and Evolutionary Botany,institute of Botany,{2. academy of sciences,beijing 100093,china) (State Key laboratory of Systematic and Evolutionary Botany Institute of Botany Chinese Academy of Sciences Beijing 100093 China)

Paeonia decomposita Hand.-*** *** is here raised to the specific rank,***(***) ***,based on its distinctiveness of four diagnostic characters:number of carpels;height of disk;number of leaflets of the lower leaves,and shape of the terminal leaflets;and unpublished molecular *** rotundiloba differs distinctly from *** in having carpels mostly 3,less often 2.or 4,very rarely 5(*** always 5,very occasionally 4 or 3),disk 8-15 mm high(vs.4-9.6 mm),leaflets mostly 19-39(vs.2.-63) in number,and ratio of length to width of the terminal leaflets 1.09-1.93(vs.1.81-2.99).

关键词： china new status Paeonia decomposita Paeonia rotundiloba Sichuan statistical analysis.

Kumada chain-growth polycondensation as a universal method for synthesis of well-defined conjugated polymers

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Science china chemistry 2010年第8期53卷 1620-1633页

作者： GENG YanHou1,HUANG Li1,2.WU ShuPeng1,2.& WANG FoSong1 1State Key laboratory of Polymer Physics and chemistry Changchun {2. of Applied chemistry,chinese academy of sciences,Changchun 13002.,china 2.raduate University of chinese academy of sciences,beijing 100049,china State Key laboratory of Polymer Physics and chemistry Changchun institute of Applied chemistry Chinese Academy of Sciences Changchun China Graduate University of chinese academy of sciences Beijing China

Kumada chain-growth polycondensation (KCGP) is a novel method for the synthesis of well-defined conjugated *** the Ni-catalyst can transfer in an intramolecular process to the propagating chain end,the polymerization follows chain-growth *** this newly developed method,various conjugated polymers,such as polythiophenes,poly(p-phenylene) (PPP),polypyrrole (PPy),and polyfluorene with controlled molecular weights and relatively narrow polydispersities (PDIs),have been ***,the polymerizations for poly(3-alkylthiophene)s (P3ATs),PPP,and PPy exhibited quasi-living characteristics,which allows preparing polymer brushes,fully-conjugated block copolymers,and macroinitiators and macro-reactants for the synthesis of rod-coil block *** the current review,the progress in this new area is summarized.

关键词： chain growth polycondensation conjugated polymers Kumada reaction block copolymers polymer brush

Ab Initio Study of the reaction: H + SO_2.HO + SO

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chinese Chemical Letters 1998年第2期9卷 181-185页

作者： Rong Shun ZHU Jian Hua HUANG Ke Li HAN and Guo Zhong HE(State Key laboratory of molecular {2. dynamics,Dalian institute of Chemical Physics, chinese academy of sciences, Dalian 11602.) State Key Lab. Molec. reaction D. Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

The reaction of H+ SO2.HO + SO was theoretically investigated sing ab initio MOmethods, and HF/TZV (d, p) level of theory was employed to locate stationary points which werethen characterized by calculation of the vibrational frequencies. Energies were estimated at the optimized geometries using MP2.TZV (d, p) calculations. The results show that the caIculated geometries- frequencies. and thermochemical data were in good agreement with available experi-mental values. The IRC calculations confirmed that nonplanar HSO2.and HOSO adducts shouldbe more reasonable than those of planar conformation.

关键词： Hydrogen Sulfur dioxtde reaction Ab initio calculation

Propensity Rules in Rotational Inelastic Collisions of NH_2.■A_1) under molecular Beam Condition

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chinese Chemical Letters 1999年第2期10卷 147-150页

作者： Feng DONG Sheng Li ZOU Hong CHEN Xue Chu LI Nan Quan LOU(State Key laboratory of molecular {2. dynamics, Dalian institute of Chemical Physics,chinese academy of sciences. Dalian, 11602.) State Key Lab. Molec. reaction D. Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 China

In this paper, it is the first time to report the study on the state-to-state rotational energytransfer (RET)of NH2.(A1)(0,9,0)under molecular beam condition in detail. Through asystematic study of the relative population transferred as functions of initially excited quantumstate, including different Ka, nuclear-spin, and even spin-doublet. some propensity rules wereobtained directly.

关键词： Single collision asymmetry top radical BET propensity rule

THEORY OF NONFLUIDIZED GAS SOLIDS FLOW AND ITS APPLICATION

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Particuology 2005年第Z1期 27-39+4页

作者： Hongzhong Li Multi-Phase reaction laboratory, {2. of Process Engineering, chinese academy of sciences, beijing 100080, P. R. china

A theory of nonfluidized gas-solids flow, which combines the theory of multiphase flow with the mechanics of particulate media, was proposed on the basis of understanding that the particles contact each other, solids and gas are in movement, and the drag force on the particles caused by interstitial gas flow is similar to gravity force having the property of mass force. Then this theory was verified by experiments on vertical and inclined moving beds, and was applied to calculation and design of equipment and devices with moving beds, such as pneumatic moving bed transport, dipleg, V-value, L-valve, orifice flow, and arching prevention. It can be used to guide the design and operation of moving beds and fixed beds.

关键词： theory nonfluidized gas-solids flow moving bed multiphase flow particulate material mechanics