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Effect of Cooling Rate on Morphology and Oxygen Permeability of Polypropylene

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International Journal of Minerals,Metallurgy and materials 1999年第3期13卷 219-223页

作者： Wei Tian Raymond T. Whodhams(material science and engineering School, university of science and technology beijing, beijing 100083, china)(Department of chemical engineering and Applied Chemistry university of Toronto, Toronto M5S IA4, Canada) material science and engineering School University of Science and Technology Beijing Beijing 100083 China Department of chemical engineering and Applied Chemistry University of Toronto Toronto Ont. M5S IA4 Canada

The influence of different cooling rates on the morphology and oxygen permeabilityr of polypropylene containing ferrocene has been investigated. The spherulitic crystalline size and structure, which can affect the oxygen permeability are dependent upon the heating temperature, annealing time and cooling rate. The modulus of the composite was measured b}' dynamic mechanical analysis.

关键词： polypropylene oxygen permeability cooling rate

An efficient chiral synthesis of (R)-N-[3-acetyl-4-(2-hydroxy-3-isopropylamino-propoxy)phenyl]-butanamide with high enantioselectivity

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science china Chemistry 2009年第8期52卷 1216-1219页

作者： WANG NaiXing1,2 & TANG XinLiang1,3 1 Technical Institute of Physics and Chemistry,Chinese Academy of sciences,beijing 100080,china 2 college of Chemistry and chemical engineering,Graduate university of Chinese Academy of sciences,beijing 100049,china 3 School of chemical engineering and Environment,beijing Institute of technology,beijing 100081,china 1. Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100080 China 2. college of Chemistry and chemical engineering Graduate University of Chinese Academy of Sciences Beijing 100049 China 3. School of chemical engineering and Environment Beijing Institute of Technology Beijing 100081 China

R-Enantiomer of the β-receptor antagonist N-[3-acetyl-4-(2-hydroxy-3-isopropylamino-propoxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient,convenient and practical synthetic *** product was detected by 1H NMR,13C NMR,and MS,and the enatiomeric excess was determined by chiral HPLC analysis using a chiracel AD-H column.

关键词： chiral synthesis enantioselectivity enatiomeric excess chiral HPLC analysis

Rheological Behavior for Polymer Melts and Concentrated Solutions——Part Ⅶ: A Quantitative Verification for the Molecular Theory of Non-linear Viscoelasticity with Entanglement Constraints in Polymer Melts

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Journal of materials science & technology 2001年第3期17卷 375-382页

作者： Mingshi SONG, Chen ZHANG and Guixian HU Research Institute of Polymeric materials, beijing university of chemical technology, beijing 100029, china E-mail: wangzhchen@*** Res. Inst. of Polymeric Mat. Beijing Univ. of Chem. Technol. Beijing 100029 China

Based on the molecular theory of non-linear viscoelasticity with constrained entanglements in polymer melts, the material functions in simple shear flow were formulated, the theoretical relations between. eta((gamma) over dot), psi (10)((gamma) over dot) and shear rate ((gamma) over dot), and topologically constrained dimension number n ' and a were derived. Linear viscoelastic parameters (eta (0) and G(N)(0)) and topologically constrained dimension number (n ' a and )over bar>) as a function of the primary molecular weight (M-n), molecular weight between entanglements (M-C) and the entanglement sites sequence distribution in polymer chain were determined. A new method for determination of viscoelastic parameters (eta (0), psi (10), G(N)(0) and J(e)(0)), topologically constrained dimension number (n ', a and v) and molecular weight (M-n, M-c and M-e) from the shear flow measurements was proposed. It was used to determine those parameters and structures of HDPE, making a good agreement between these values and those obtained by other methods. The agreement affords a quantitative verification for the molecular theory of nonlinear viscoelasticity with constrained entanglement in polymer melts.

关键词： Rheological Behavior for Polymer Melts and Concentrated Solutions A Quantitative Verification for the Molecular Theory of Non-linear Viscoelasticity with Entanglement Constraints in Polymer Melts Part

Gas-sensing properties of nanocomplex metal oxide

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Progress in Natural science:materials International 2005年第7期15卷 669-672页

作者： CHEN Liangyuan, HE Zhusheng, YAN Tao, BAI Shouli, CHEN Aifan and LIU Chung Chiun ( Electronics Design Center, Case Western Reserve university, Cleveland, OH 44106, USA Department of Chemistry and chemical engineering, Baoji university of Arts and science, Baoji 721007, china college of science, beijing university of chemical technology, beijing 100029, china) Electronics Design Center Case Western Reserve University Cleveland 01-I 44106 USA. Department of Chemistry and chemical engineering Baoji University of Arts and Science Baoji 721007 China. college of science Beijing University of Chemical Technology Beijing 100029 China

The development of CuO/CeO2 nanocomposites as the sensing material of semiconductor gas sensors is reported. CuO/CeO2 nanocomplex oxide is prepared by modified sol-gel method that uses copper nitrate, cerium nitrate and ethylene glycol as precursors. The optimized synthesis parameters and processing condition have been established. The particle size and distribution, phase morphology, specific surface, electronic states of atoms and gas sensing properties have been systematically characterized by Transmission Electron Microscope (TEM), Brunauer Emmett Teller (BET), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and gas sensitivity measurement. The results show that the sensor sensitivity depends on particle size, Cu/Ce cation ratio and calcination temperature. The effects of calcinations temperature and CuO loading on the gas sensitivity are also examined. The optimum calcination temperature and the CuO content for the highest sensitivity are 600 ℃and 12% , respectively. The combination of excellent thermal stability and tunable sensing properties through careful control of the processing parameters and selection of material composition gives rise to novel nanocomposites attractive to the sensitive and selective detection of a variety of toxic and combustible gases.

关键词： copper oxide cerium oxide nanocomposite CO gas sensitivity.

Oxygen Permeability of Polypropylene Containing Polyisobutene with Magnesium Acetate

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International Journal of Minerals,Metallurgy and materials 2000年第2期14卷 118-121页

作者： Wei Tian Raymond T. Woodhams(material science and engineering School, university of science and technology beijing, beijing 100083, china)(Dept. of chemical engineering and Applied Chemistry, university of Toronto, Torono M5S IA4, Canada) Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Univ Toronto Dept Chem Engn & Appl Chem Toronto ON M5S 1A4 Canada

The oxygen permeabilities of polypropylene films are reduced by adding a minor percentage of a polyisobutene ionomer. The polyisobutene ionomers were prepared by in situ salt exchange of magnesium acetate with maleated polyisobutenes of commercially available low relative molecular mass. The more polar magnesiurn salts aided phase separaion during crystallization from the molten polypropylene mixtusre. Scanning electron microscope photographs revealed that the polyisobotene ionomer is largely concentratd in the amorphous regions between the polypropylene spherulites, where the ionomer tends to concentrate during crystallization. The influence of the polyisobutene ionomer on the oxygen permeability of polypropylene was found to be slightly dependent upon the relative molecular mass of the polyisobutene precursor. Under optimum conditions, the oxygen permeability of polypropylene is reduced by 20%with only 1% additive.

关键词： oxygen permeability polypropylene polyisobutene

Influence of Mo on Dynamic Continuous Cooling Transformation of 1000 MPa Cold Rolled Dual Phase Steel

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Journal of Iron and Steel Research International 2011年第S1期18卷 296-299页

作者： ZHAO Xian-meng,KANG Yong-lin,HAN Qi-hang (School of material science and engineering.university of science and technology beijing,beijing 100083,china) Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

The expanding curves of two kinds of 1000 MPa ultra-high strength cold rolled dual phase steels,which were C-Si-Mn-Cr and C-Si-Mn-Cr-Mo steel respectively,were detected on Gleeble-1500 thermal-mechanical simulator at different cooling *** with metallographic and hardness methods,the continuous cooling transformation curves (CCT) of the two steels were *** results showed that Mo could raise the A r3 temperature,and strongly restrain the pearlite and bainite *** reason for this was the interaction that the addition of Mo could increase the chemical driving force of ferrite transformation and the activation energy for the diffusion of carbon in austenite,which could decelerate the ferrite *** hardness of the two steels was similar in the cooling rates range of this experiment and got higher with the increase of the cooling *** the cooling rates were above 7 ℃/s,the hardness almost kept constant because the most part of the microstructure was martensite.

关键词： Mo dual phase steel cold rolled CCT ultra-high strength

Analysis of variance for testing method of cement in determination of strength

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Progress in Natural science:materials International 2011年第4期21卷 341-346页

作者： Hong HUANG,Xiao-dong SHEN State Key Laboratory of materials-Oriented chemical engineering,college of material science and engineering, Nanjing university of technology,Nanjing 210009,china State Key Laboratory of materials-Oriented chemical engineering College of Material Science and Engineering Nanjing University of Technology Nanjing 210009 China

The statistical tools such as descriptive statistics,full factorial design and analysis of source of variation were used to identify the potential factors that impact the validity of testing method for determining the strength of *** results showed that personal error impacted both accuracy and precision of test *** time associated with temperature fluctuation resulted in strength variation but did not impact the precision of test in all curing *** compactions did not impact the precision of test but resulted in the strength variation on 3 d and 28 d *** methods for the initial moist air curing significantly impacted the precision of testing method and resulted in the strength variation of cement on 1 d.

关键词： testing method of cement analysis of variance strength accuracy precision

Preparation and characterization of uniform circinate aggregates of sheet ZnO nanoparticles

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Rare Metals 2008年第1期27卷 36-40页

作者： LIU Jiaxiang DING Deling WANG Lisheng and HAN Yuexin The State Key Laboratory of chemical Resource engineering College of Materials Science and Engineering Beijing University of Chemical Technology Be~iing100029 China School of Resources and Civil engineering Northeastern University Shenyang 110004 China

Uniform circinate aggregates of sheet ZnO nanoparticles with a specific surface area of 24 m^2·g^-1 were prepared by the direct precipitation *** circinate aggregates were hexagonal ZnO,with the wall thickness ranging from 0.5 to 1 μm and the diameter ranging from 5 to 10 μ*** backs of the circinate aggregates were regularly arranged by numerous sheet ZnO nanoparticles with a thickness of 30-80 nm and a diameter of 300-400 *** precursors were aggregates of sheet Zn5（CO3）2（OH）6 nanoparticles,which were decomposed into ZnO by calcining in air in the range of 200-285°C,and the ZnO retained the similar special *** C2H5OH content had a significant effect on the formation of sheet *** centripetal force,the Van der Waals force,and the hydrogen bond were deduced as the driving forces of the formation of circinate.

关键词： nano-ZnO circinate aggregates preparation technology microstructure characterization

Synthesis and Characterisation of Water-Soluble Carboxymethyl-Cyclodextrin Polymer as Capillary Electrophoresis Chiral Selector

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Chinese chemical Letters 2000年第1期11卷 69-70页

作者： Xue Yan SHI Rui Fang FAN Yue Qin ZHANG Jun Ling GU Ruo Nong FU( college of chemical engineering and material science beijing Institute of technology, beijing 100081) Coll. of Chem. Eng. and Mat. science Beijing Institute of Technology Beijing 100081 China

The water-soluble carboxymethyl-cyclodextrin polymer (CM-CD polymer) was synthesized and used as capillary electrophoresis chiral selector. Verrapamil and thiopentorusodium were well separated using CM-CD polymer as c... 详细信息

关键词： Carboxymethyl-cyclodextrin polymer capillary electrophoresis chiral selector.