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Enhancement of Solubility of Troeger's Base in Supercritical Carbon Dioxide by Methanol

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Chinese chem.cal Letters 2000年第9期11卷 823-826页

作者： Qi Long REN Mci HUANG Bao Gen SU Ping Dong WU National lab.ratory of Secondary Resources chem.cal Engineering Zhejiang University, Hangzhou 310027 natl. lab. Secdry. Rsrc. chem. Eng. Zhejiang University Hangzhou 310027 China

The solubility of Troeger's base (TB) in SC-C_2/CH_3OH was measured at 308K in the pressure range of 8 to 13 MPa. and methanol concentration ranges from 0 to 20 mol%. The solubility increases dramatically with methanol concentration. Comparison of solubility in supercritical CO_2 with and without 10 mol% CH3,OH in the prcssure of 8 MPa at 308K implies that both curves are steep in the lower pressure range but become smooth as the pressure increases.

关键词： Solubility. supercritical CO_2 methanol Troeger's base.

Systematic study of the transfer of amino acids across the water/1,2-dichloroethane interface facilitated by dibenzo-18-crown-6

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Science China chem.stry 2004年第1期47卷 24-33页

作者： CHEN Yong, YUAN Yi, ZHANG Meiqin, LI Fei, SUN Peng, GAO Zhao & SHAO YuanhuaState Key lab.ratory of Electroanalytical chem.stry, Changchun Institute of appl.ed chem.stry, Chinese Academy of Sciences, Changchun 130022, China College of chem.stry and Molecular Engineering, Peking University, Beijing 100871, China lab. of Electroanalytical chem. Changchun Inst. of Appl. Chem. Chinese Acad. of Sci. Changchun 130022 China Coll. of chem. and Molecular Eng. Peking Univ. Beijing 100871 China

Facilitated ion transfer reactions of 20 amino acids with dibenzo-18-crown-6 (DB18C6) at the water/1,2-dichloroethane (W/DCE) interfaces supported at the tips of micro- and nano-pipets were investigated systematically using cyclic voltammetry. It was found that there were only 10 amino acids, that is, Leu, Val, lie, Phe, Trp, Met, Ala, Gly, Cys, Gin (in brief), whose protonated forms as cations can give well-defined facilitated ion transfer voltammograms within the potential window, and the reaction pathway was proven to be consistent with the transfer by interfacial complexation/dissociation (TIC/TID) mechanisms. The association constants of DB 18C6 with different amino acids in the DCE (β0), and the kinetic parameters of reaction were evaluated based on the steady-state voltammetry of micro- or nano-pipets, respectively. The experimental results demonstrated that the selectivity of complexation of protonated amino acid by DB18C6 compared with that of alkali metal cations was low, which can be attributed to the vicinal effect arising from steric hindrance introduced by their side group and the steric bulk effect by lipophilic stabilization. Moreover, the association constants and the standard rate constants for different amino acids showed good correlations with their hydrophobicity (π), except Gly and Met, which inferred that the selectivity of such heterogeneous complex reaction for different amino acids with DB18C6, was not only affected by discrimination in binding these ions to the crown ether macro-cycle, but also significantly modified by the ion transfer Gibbs energy which was closely related to the structure of the transferred ions, protonated amino acids.

关键词： micro-/nano-pipet, water/1,2-dichloroethane interface, facilitated ion transfer, cyclic voltammetry, amino acid.

Preparation and Characterization of Palladium Colloidal Nanoparticles by Thermal Decomposition of Palladium Acetate with Microwave Irradiation

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Journal of Materials Science & Technology 2005年第2期21卷 187-190页

作者： Yixian CHEN, Baolin HE and Hanfan LIU Hubei Key lab.ratory for Catalysis and Material Science, University of South-Central for Nationalities, Wuhan 430074, China PCLCC, State Key lab.ratory of Polymer Physics and chem.stry, Institute of chem.stry, Chinese Academy of Sciences, Beijing 100080, China lab. for Catalysis and Mat. Sci. Univ. of South-Central for Natl. Wuhan 430074 China lab. of Polymer Phys. and chem. Inst. of Chem. Chinese Acad. of Sci. Beijing 100080 China

A series of solvent-stabilized palladium colloidal nanoparticles were prepared via thermal decomposition of palladium acetate methylisobutylketone (MIBK) solution in the presence of alkali and alcohol with microwave irradiation. The colloidal nanoparticles were characterized with TEM, XPS and XRD. The average diameters of nanoparticles increase from 30 to 40 nm with the increase in concentration of palladium acetate. TEM and XRD observation demonstrated that the palladium colloidal nanoparticles were clusters agglomerated from hundreds of smaller palladium crystallines with size of 3-4 nm. The influence of the concentrations of alkali and alcohol to the particle size was also discussed.

关键词： Thermal decomposition Microwave Palladium acetate Methylisobutylketone

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

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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 Academy of Sciences, Shenyang 110016, China 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 electrochem.cal 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

Triterpenoid Saponins from Clematis tangutica

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Chinese chem.cal Letters 1999年第5期10卷 391-394页

作者： Hui Min ZHONG Chang Xiang CHEN Xuan TIAN Yu Xin CfIUI Yao ZuCHEN(Department of chem.stry. State Key lab.ratory of appl.ed organ.c chem.stry.Lanzhou University. Lanzhou 73000Kunming Institute of Botany.The Academy of Sciences of China, Kunming 630204Dep Department of chem.stry State Key Lab. of Appl. Organ. Chem. Lanzhou University Lanzhou 73000 China Kunming Institute of Botany Academy of Sciences of China Kunming 650204 China College of Pharmacy Beijing Univ. of Medical Sciences Beijing 100083 China Department of chem.stry Zhejiang University Hangzhou 310027 China

Two new triterpenoid saponins, tanguticoside A and B were isolated from aerial part of Clematis tangutica. Their structures were elucidated as 3-O-beta-D-glucopyranosyl hederagenin 28 O-alpha-L-rhamnopyranosyl- (1-->4)-beta-D-glucopyranosyl- (1-->6)-beta-D-glucopyranosidel and 3-O-beta-D-glucopyranosyl ranosyl- (1-->2)-beta-D-glucopyranosyl hederagenin 28-O-alpha-L-rhamnopyranosyl- (1-->4)-beta-D-glucopyranosyl- (1-->6)-beta-D-glucopyranoside2, respectively.

关键词： Clematis tangutica ranunculaceae triterpenoid saponins hederagenin tanguticoside A and B

Effect of Templates on the Structure and Stability of Ti-TMS

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Chinese chem.cal Letters 1999年第3期10卷 267-268页

作者： Qing DAI Nong Yue HE Xing Li WANG Xun Wei SHEN Yan GUO Chun Wei YUANI(National lab.ratory of Molecular and Biomolecular Electronics)(Department of chem.stry and chem.cal Engineering, Southeast University, Naming 210096) natl. lab. Molec. Biomol. E. Southeast University Nanjing 210096 China Dept. of chem. and chem. Engineering Southeast University Nanjing 210096 China

Pure Mesoporous TiO2 molecular sieves (Ti-TMS) were synthesized with different templates for the first time and the templates can be successfully removed by refluxing the samples in the EtOH/H2O/KOH solution. The XRD pattern and TEM confirm that the uniformity and stability of Ti-TMS2 synthesized with dodecylamine as template is obviously inferior to that of Ti-TMS1 prepared with dodecylphosphate and hexadecylphosphate as templates. Furthermore, after the templates were removed, the mesostructure of Ti-TMS1 was preserved to a great degree than that of Ti-TMS2.

关键词： TiO2 mesoporous molecular sieves template

A Facile Synthetic Approach to Two Chalcones

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Chinese chem.cal Letters 2001年第11期12卷 957-958页

作者： Du, ZT Li, SB Lanzhou Univ Inst Organ Chem Natl Lab Appl Organ Chem Lanzhou 730000 Peoples R China

A facile synthetic route for two chalcone analogues was developed. The key step was selective deprotection of MOM in aryl methyl ether 6 by silica gel.

关键词： chalcone synthesis

Molecular electronegativity in density functional theory(Ⅷ)——Charge polarization modes in a closed system

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Science China chem.stry 2000年第2期43卷 187-195页

作者：杨忠志王长生 Department of chem.stry Liaoning Normal University Dalian 116029 China natl. Key lab. Theor. Compl. chem. Jilin University Changchun 130023 China

Based on the density functional theory and the atom-bond electronegativity equalization model (ABEEM), a method is proposed to construct the softness matrix and to obtain the electron population normal modes (PNMs) for a closed system. Using this method the information about the bond charge polarization in a molecule can be obtained easily. The test calculation shows that the PNM obtained by this method includes all the modes about the bond charge polarization explicitly. And the bond charge polarization mode characterized by the biggest eigenvalue, which is the softest one of all modes related with chem.cal bonds, can describe the charge polarization process in a molecule as exquisitely as the corresponding ab initio method.

关键词： atom-bond electronegativity equalization model closed system softness matrix electron population normal mode bond charge polarization.

Experimental and Numerical Investigations of an Ice-slurry Generator

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过程工程学报 2004年第1期4卷 1-7页

作者：洪若瑜董梁尚德义徐建生 Kawaji M Dept. chem. & chem. Eng. Soochow University Suzhou Jiangsu 215006 China Dept. chem. Eng. & appl. chem. University of Toronto Toronto ON M5S 3E5 Canada

A new test facility equipped with refrigerant and brine circulation systems, and a rotating-scraper ice-slurry generator was constructed to analyze the ice-slurry flow and heat transfer accompanied by phase change in an industrial generator. The axial and transverse brine temperature and ice fraction concentration profiles in the ice generator were measured. The heat transfer efficiency lower than the average was identified in the upper half of the ice generator and its cause was determined by conducting three-dimensional numerical simulation using a commercial CFD code, FLUENT. Approaches of improving the brine-side heat transfer rates were investigated by incorporating extra mixing blades from numerical simulation.

关键词：泥浆泵计算流体力学实验研究数值模拟