检索结果-南通市图书馆

SILICA-SUPPORTED NICKEL AND ZIRCONIUM CATALYSTS FOR BRANCHED POLYETHYLENE

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2003年第4期21卷 453-458页

作者：孙文华 State Key Laboratory of Engineering Plastics the center for molecular sciences institute of chemistry Chinese Academy of sciences Beijing 100080 China Stt. Key Lab. of Eng. Plastics Center for Molecular Sciences Chinese Academy of Sciences Beijing 100080 China

8-Aminoquinoline nickel dichloride and bis(cyclopentadienyl)zirconium dichloride (Cp_2ZrCl_2) were supportedsimultaneously on silica to produce branched polyethylene successfully by combined polymerization. The supportedpolymerization results showed that the molecular weight of polyethylene increased while the molecular weight distributionbecame wider and the molecular chains of oligomers remaning in the final solution became shorter as compared to theoligomers obtained in polymerization processes with pure 8-aminoquinoline nickel dichloride catalysis, as well as theCp_2ZrCl_2 and nickel combination system. With decreasing amount of Ni catalyst in the supported catalyst, the molecular chains of oligomers in the resulting solution became shorter, while α-olefin selectivity increased.

关键词： 8-Aminoquinoline nickel dichloride, Cp_2ZrCl_2 Silica supported catalysts Branched polyethylene

CHEMICAL STRUCTURE DEPENDENCE OF THE INTERNAL ENERGY CONTRIBUTION IN RUBBER ELASTICITY

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2001年第5期19卷 447-449页

作者： Juan Sun Xiao-zhen Yang Polymer Physics Laboratory center for molecular sciences, institute of chemistry Chinese Academy of sciences Beijing 100080 China 中科院化学所高分子物理及化学国家重点实验室北京

Conformational elasticity theory recently developed has been used to explore the internal energy contribution to the elastic force f(e)/f as a function of strain for poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene). Calculated f(e)/f values are in good agreement with those obtained experimentally. Results show that behavior of f(e)/f is mainly contributed by chemical structure, or intramolecular interaction, supporting the experimental observations, and that the internal energy contribution is strain dependent.

关键词： conformational elasticity theory internal energy contribution poly(cis-1,4-isoprene) poly(trans-1,4-isoprene)

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

在线全文

学校读者我要写书评

暂无评论

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) center for molecular sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100080 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

A Dye-sensitized Nanocrystalline Solid State Photovoltaic Cell

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2000年第9期11卷 813-814页

作者： Dong She ZHANG Xu Rui XIAO Laboratory of photochemistry, center for molecular sciences, institute of chemistry, Chinese Academy of sciences, Beijing, 100080 Laboratory of Photochemistry Center for Molecular Sciences Institute of Chemistry Beijing 100080 China

A new type of dye-sensitized nanocrystalline solid state photovoltaic cell based on the wide band gap n-TiO2/p-CuI heterojunction was fabricated. Tetra-carboxyphenyl porphyrine (TPP-(COOH)(4)), squarylium cyanine derivative (SQ-(CH2),(SO3Py+)-Py-.) and ruthenium bipyridyl complex (RuL2(NCS)(2)) were used as photosensitizers. Larger photocurrents and photovoltages were shown in the cell sensitized by ruthenium bipyridyl complex and can be further increased by intercalation of a TiO2 thin underlayer.

关键词： nanocrystalline TiO2 electrode dye sensitization solid state cell

A Calorimeter for Measuring the Enthalpy of Solution of Solid Solutes in Supercritical Fluids and Study on CO2-Naphthlene System

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2001年第1期12卷 79-80页

作者： Xiao Gang ZHANG, Guang Ying YANG , Bu Xing HAN*, Xi Feng ZHANG, Hai Ke YAN center for molecular sciences, institute of chemistry, the Chinese Academy of sciences, Beijing 100080 center for molecular sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

An apparatus for measuring the enthalpy of solution of solids in supercritical fluids (SCFs) was constructed. The enthalpy of solution (ΔH) of naphthalene in supercritical (SC) CO2 was measured at 308.15 K in the pressure range from 8~11 MPa. It was found that ΔH was negative in the pressure range from 8 to 10 MPa, and the absolute value of ΔH decreases with increasing pressure. However, ΔH became positive at the pressures higher than 10 MPa. This unusual phenomenon can be explained by clustering between CO2 and naphthalene.

关键词： Solution enthalpy supercritical fluid molecular interaction

POLYMERIZATION OF ETHYLENE WITH UNSYMMETRIC 2,6-BIS(IMINO)PYRIDINE IRON(Ⅱ)COMPLEX

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 Journal of Polymer Science 2002年第3期20卷 205-211页

作者： Zhi Ma Wen-hua Sun Zi-long Li Chang-xing Shao You-liang Hu State Key Laboratory of Engineering Plastics and the center for molecular sciences institute of chemistry Chinese Academy of sciences, Beijing 100080 China State Key Lab. of Engineering Plast. Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

An unsymmetric 2,6-bis(imino)pyridine iron(II) complex 1' was synthesized. The relationship between catalyststructure and its activity in ethylene polymerization is discussed. The kinetic behavior of ethylene polymerization and theeffects of polymerization conditions such as temperature, aluminum/iron molar ratio on the activity of catalyst and thecharacteristics of polyethylene were reported. The unsymmetric catalyst 1' has a good catalytic performance of 3.47×10~6 gPE·mol^(-1)·Fe·h^(-1) at 40℃ with aluminum/iron molar ratio = 2500. A dependence of catalyst activity on themethylaluminoxane (MAO) concentration and reaction temperature was found. The molecular weight (MW) of polyethylenewith broad dispersity is about 10~4-10~5 g/mol. The melting temperature and branching of polyethylenes vary with changingreaction temperature and aluminum/iron molar ratio.

关键词： Unsymmetric 2,6-bis(imino)pyridine iron(Ⅱ) complex Ethylene polymerization Catalyst structure Catalytic activity

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

在线全文

学校读者我要写书评

暂无评论

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

A Novel Fluorescent Probe for Lead Ions

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2003年第10期14卷 1024-1026页

作者： Ming SUN, Di Hua SHANG GUAN, Hui Min MA, Li Hua NIE, Xiao Hua LIShao Xiang XIONGLaboratory of Chemical Biology, center for molecular sciences, institute of chemistry, Chinese Academy of sciences, Beijing 100080 center for molecular sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

A new fluorescent probe for lead ions,p-nitrophenyl 3H-phenoxazin-3-one-7-yl phosphoric acid (NPPA), has been synthesized by linking resorufin (serving as a fluorophore and electron acceptor) to p-nitrophenol (serving as a fluorescence quencher and electron donor) through phosphodiester bonds. When NPPA was irradiated with light, intramolecular fluorescence self-quenching took place due to the PET (photoinduced electron transfer) from the donor to the acceptor. However, upon addition of PbII, the phosphate ester bonds in the probe were cleaved and the fluorophore was released, accompanying the retrievement of fluorescence.

关键词： Fluorescent probe lead phosphodiester hydrolysis.

Controlled assembly of copper phthalocyanine with 1-iodooctadecane

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第15期48卷 1519-1524页

作者： LEI Shengbin, WANG Chen, WAN Lijun & BAI Chunli center of molecular sciences, institute of chemistry, Chinese Academy of sciences, Beijing 100080, China Correspondence should be addressed to Bai Chunli (e-mail: clbai@ ***) center of molecular sciences Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

The binary assembly behavior of 1-iodoocta- decane with substituted phthalocyanine (Pc) is studied using the scanning tunneling microscopy (STM). By altering the substituted alkyl groups attached to the phthalocyanine ring, either uniform assembly or phase separation behavior can be observed. It is suggested that the strength of intermolecular interaction between phthalocyanine molecules is the determining factor for the assembly structure.

关键词：铜酞菁碘代十八烷扫描隧道电子显微镜化学结构