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IRC analysis of methanol carbonylation reaction catalyzed by rhodium complex

Science china Chemistry 2004年第1期47卷 41-49页

作者： HAO Maorong, FENG Wenlin, Jl Yongqiang & LEI Mingfaculty of Science, Beijing University of chemical {2., Beijing 10002., china faculty of chemical engineering, Ningxia University, yinchuan 750021, china faculty of Science Beijing University of Chemical Engineering Beijing China faculty of chemical engineering Ningxia University Yinchuan China

In the reaction cycle for methanol carbonylation catalyzed by Rh complex, the structure geometries of the reactant, intermediates, transition states and product of each elemental reaction have been studied by using the energy gradient method at HF/LANL2.Z level, and the changes of their potential profiles have also been calculated. Through IRC analyses of the transition states for each elemental reaction, it is confirmed that the various structure geometries obtained are stationary points on the cycle reaction pathway of methanol carbonylation catalyzed by Rh complex, and the changes are given in energies and structure geometries of the reactant molecules along the reaction pathway of lowest energy. It has been proposed that the geometrical conversions of intermediates play an important role during the cycle reaction. Through analyses of structure geometries, it has been suggested that, in addition to cis- and transstructure exchange linkage of catalysis reactive species, the two pathways, cis- and frans-catalyzed cycle reactions, can also be linked through geometrical conversion of intermediates, of which the activation energy is 49.79 kJ/mol. Moreover, the reductive elimination elemental reaction may be neither c/s-cycle nor trans- one, showing that the cycle reaction can be achieved through various pathways. However different the pathway, the oxidative addition elemental reaction of CH3I is the rate-controlling step.

关键词： rhodium complex catalyst, methanol carbonylation, ab initio method, homogeneous catalysis.

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Reversible folding/unfolding of small α-helix in explicit solvent investigated by ABEEMσπ/MM

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Science china Chemistry 2009年第11期52卷 1917-1924页

作者： LIU Cui & YANG ZhongZhi Chemistry and chemical engineering {2.,Liaoning Normal University,Dalian 11602.,china Chemistry and chemical engineering {2. Liaoning Normal University Dalian China

We have performed molecular dynamics simulations on the reversible folding/unfolding of small α-helix(short Ala based peptide Ala5) in explicit water solvent in terms of ABEEMσπ/MM.A dynamics analysis shows that the α-helical turn can be preserved up to a period of about 2.ns at 300 K,which supports the conclusions of Margulis et *** time trajectory of the root mean square deviation between the heavy atoms of the backbone and the helical reference structure indicate that "helix melting and formation occurs rapidly on a time scale of 0.1 ns at 300 K" is not a felicitous *** first quantificationally concluded that the helix nucleation can maintain 2.ns,1―1.5 ns and 0.8 ns for Ala5 at 300 K,400 K and 500 K,***,increasing temperature dose not alter the pathway of folding/unfolding,but change the *** analysis of structures in a "transition-state ensemble" shows that helix-to-coil transitions occurs predominantly through breaking of hydrogen bonds at the helix ends(92.),particularly at the C-terminus(50%).Hydrogen bonds' breaking and formation occurs on a time scale of 0.1 ns.

关键词： reversible folding/unfolding of protein Ala5 temperature hydrogen bond

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Application of the ABEEM/MM model in studying the properties of the water clusters(H_2.)_n(n=7-10)

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Science china Chemistry 2007年第2期50卷 190-204页

作者： QIAN Ping & YANG ZhongZhi faculty of Chemistry and chemical {2.,Liaoning Normal University,Dalian 11602.,china faculty of Chemistry and chemical {2. Liaoning Normal University Dalian China

ABEEM/MM model has been applied to compute the various properties characterizing water clusters(H2.) n(n = 7-10) ,such as optimized geometries,the hydrogen bonds number,cluster interaction en-ergies,stabilities,ABEEM charge distributions,dipole moments,structural parameters,and so on,and to describe the transition reflected by the hexamer region from two-dimensional(from dimer to pen-tamer) to three-dimensional structures(for clusters larger than the hexamer) .

关键词： ABEEM/MM model the atom-bond electronegativity equalization method molecular mechanics water clusters

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Synthesis and photochromic properties of WO_3 powder induced by oxalic acid

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Science china Chemistry 2009年第5期52卷 609-614页

作者： SHEN Yi1, ZHU Hua1, HUANG Rong1, ZHAO Li2.& YAN ShaNing1 1 faculty of Material Science and chemical {2., china University of Geosciences, Wuhan 430074, china 2.faculty of Materials Science and {2., Hubei University, Wuhan 430062. china faculty of Material Science and chemical {2. China University of Geosciences Wuhan China faculty of Materials Science and engineering Hubei University Wuhan China

Tungsten trioxide powder with the novel morphology was prepared via the hydrothermal method with oxalic acid as the organic inducer, the structure and shape of which were detected by X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET. Furthermore, photochromic properties of the as-prepared powder samples were tested by an ultraviolet-visible spectrophotometer combined with a color difference meter. The corresponding results indicated that the induced product was still hexagonal WO3, made up of regularly spindle particles with 2.0-300 nm in length and 30-50 nm in width. The ratio of the length and width was from 4 to 10. Moreover, the special morphology improved its absorptive capacity to the excitation light source, resulting in its high photochromic properties.

关键词： WO3 powder photochromism oxalic acid organic inducer

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On-line parallel reversed phase two-dimensional liquid chromatography for high-throughput analysis of complex proteomic samples

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Science china Chemistry 2006年第6期49卷 527-533页

作者： WANG Zhicong1,3, ZHANG Qinghe2. LI Tong2. ZHAO Zhongyi3 & ZHANG Weibing1 1. Dalian Institute of chemical Physics, Chinese Academy of Sciences, Dalian 116011, china 2. Dalian Elite Analytical Instrument Co., Ltd., Dalian 116011, china 3. faculty of Material Science and chemical engineering, china University of Geosciences, Wuhan 430074, china Dalian Institute of chemical Physics Chinese Academy of Sciences Dalian China faculty of Material Science and chemical {2. China University of Geosciences Wuhan China Dalian Elite Analytical Instrument Co. Ltd. Dalian China

A comprehensive two-dimensional liquid chromatographic system (2. SCX/RP) is con- structed with a 10-port-2.way valve using strong cation exchange chromatography (Hypersil SCX, 100 mm×4.6 mm I.D.) followed by reversed phase chromatography (Hypersil BDS C18, 15 mm×4.6 mm I.D.) to separate the complex peptides from globin peptic hydrolysate. After the sample was loaded on the SCX column, the phosphate buffer (pH 4.0) was used to elute the peptides. Then, elutes flowed through the interface and the peptides focused on the head of the trapping columns (Hypersil BDS C18, 15 mm×4.6 mm I.D.) but salt passed into the waste. After the valve was switched, the samples were flushed with a backward flow into the RP analytical column. The peptides on the SCX were eluted with 12.discontinuous steps linearly increasing salt concentrations. The peptides enriched on the trapping column were desalted and separated by the RP columns. The resolution and the resolved peaks of the 2. SCX/RP system were greatly increased and the total peak capacity reached as high as 2.80.

关键词： two-dimensional liquid chromatography, interface, trapping column, proteomics, globin.

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MATHEMATICAL MODEL OF THE MICROBIAL FLOODING

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Journal of Hydrodynamics 2003年第4期15卷 104-108页

作者： Lei Guang-lun, Zhang Zhong-zhi, Chen Yue-ming faculty of chemical engineering, University of Petroleum, Beijing 102.49, china faculty of Chem. Eng. Univ. of Petroleum Beijing 102249 China

On the basis of growth kinetics of microorganism and the principle ofmaterial balance, equations were derived to describe microbial growth, nutrient consumption,metabolites production and their transport in formation. The changes in porosity, permeability, oilviscosity and capillary force were also described as the main facturs of microbial flooding. Forreservoirs with black oil properties, three-dimensional three-phase mathematical models with thecosidara-tion of multi-microbial components were established to depict microbial flooding oil. Withthis model, calculated results are in good agreement with experimental data.

关键词： microbial flooding enhance oil recovery mathematical model

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EXPERIMENT AND THERMODYNAMIC ANALYSIS ON THE PHASE STABILITY OF LOW ACTIVATION Fe-Cr-Mn(W,V) ALLOY

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Acta Metallurgica Sinica(English Letters) 2002年第6期15卷 492-498页

作者： Q.M. Yu, B.F. Hu, C.C. Jia and EM. ChenSchool of Materials Science and engineering of University of Science and Technology Beijing, Beijing 100083, chinaNingxia University,{2.,china School of Materials Science and engineering of University of Science and Technology Beijing Beijing 100083 China

Phase stability of four different chemical component Fe-Cr-Mn(W, V) alloys are investigated by experimental method and thermodynamic model in this paper. It is indicated that the main phase of four alloys after aged under 62., 673, 773K for 2.0h are austenitic phase. The results of Thermo-Calc, which are based on Gibbs energy, show that the phases of four alloys under ihe same temperature as experimental method are single austenitic phase. The results of experimental method and Thermo-Calc agree well.

关键词： phase stability Fe-Cr-Mn(W V) alloy Thermo-Calc

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Analysis of trace mercury in water by solid phase extraction using dithizone modified nanometer titanium dioxide and cold vapor atomic absorption spectrometry

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Rare Metals 2007年第6期26卷 541-546页

作者： MA Xiaoguo HUANG Bei CHENG Meiqing faculty of Environmental Science and engineering Guangdong University of Technology Guangzhou 510090 China Department of chemical engineering Maoming University Maoming 525000 China

A new method for analysis of trace mercury in water samples was developed, based on the combination of preconcentration/separation using dithizone-modified nanometer titanium dioxide （TiO2. as a solid phase extractant and determination by cold vapor atomic adsorption spectrometry （CVAAS）. Dithizone was dissolved with alcohol and loaded on the surface of nano-sized TiO2.powders by stirring. The static adsorption behavior of Hg^2.on the dithizone-modified nanoparficles was investigated in detail. It was found that excellent adsorption ratio for Hg^2. could be obtained in the pH range of 7-8 with an oscillation time of 15 rain, and a 5 mL of 3.5 mol·L^-1 HCI solution could quantitatively elute Hg^2. from nanometer TiO2.powder. Common coexisting ions caused no obvious influence on the determination of mercury. The mechanisms for the adsorption and desorption were discussed. The detection limit （30） for Hg^2. was calculated to be 5 ng·L^-1. The proposed method was applied to the determination of Hg^2. in a mineral water sample and a Zhujiang River water sample. By the standard addition method, the average recoveries were found to be 94.4%-108.3% with RSD （n = 5） of 2.9%-3.5%.

关键词： analytical chemistry mercury solid-phase extraction TiO2.nanoparticle cold vapor atomic adsorption spectrometry (CVAAS)

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New development of materials used in BFCs

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化工进展 2010年第S1期29卷 551-556页

作者： WANG Li (faculty of Environmental and biological engineering,Shenyang University of {2. Technology,Shenyang,110142.china)

Electrodes,catalysts,membranes,if present,are three main components in constructing an MFC for harvesting desired maximum power density and achieving higher coulombic efficiency (CE).Great improvements have been made,based on previous researches,in developing and diversifying materials,aside from *** most familiar to us are widely used carbon *** anodes,carbon matrix composites(e.g.,a combination of polyaniline(PANI)with TiO2.using carbon as substrate)have gained special attention,though carbon material itself can exhibit excellent performance by diversifying molecular structures such as carbon nanotubes(CNTs).In the meanwhile,the evolution of MFC architectures,heading to the direction of improving power generation,contributes to the combination of membranes and cathodes from separate modes to diverse assemblies,on which all sorts of catalysts,such as from commonly used Pt to iron phthalocyanine (Pc),metal tetramethoxyphenylporphyrin(TMPP),MnOx,or pyrolyzed iron(Ⅱ)phthalocyanine (pyr-FePc),can be immobilized through synthesis of these catalysts with polymer such as Nafion 117 (Dupont Co.,USA)or tetrafluoroethylen(eTeflon)containing functional groups or Polypyrrol(ePPy).In addition,catholytes with aqueous cathode immersed or flowing through the surface of air-cathode are favorably proposed containing transition metal redox couples or iron chelates.

关键词： BFCs anode cathode membrane catholyte

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Synthesis and photoluminescence property of red phosphors LiEu_(1-x)Y_x(WO_4)_(0.5)(MoO_4)_(1.5) for white LED

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Science china(Technological Sciences) 2009年第7期52卷 1913-1918页

作者： XIE An, YUAN XiMing, WANG JuanJuan & WANG Feng engineering Research Center of Nano-Mineral Materials and Application, Ministry of Education, faculty of Materials Science and {2. engineering, china University of Geosciences, Wuhan 430074, china engineering Research Center of Nano-Mineral Materials and Application Ministry of Education Faculty of Materials Science and Chemical Engineering China University of Geosciences

A series of novel red phosphors LiEu1-xYx(WO4)0.5(MoO4)1.5 (x=0, 0.1, 0.2. 0.3, 0.4, 0.5, 0.6, 0.8) were synthesized by conventional solid state reaction method with the starting materials: WO3, MoO3, Eu2.3, Li2.O3 and Y2.3. The spectrum and the crystal structure of the phosphors were characterized by F-4500 and XRD respectively. Meanwhile the effects of flux and Y3+ concentration on the crystal structure and luminescent properties of the phosphors were investigated. The results showed that the optimal content of flux (WAlF3/WH3BO3=1/1) was 1 wt% and the optimal doping concentration of Y3+ was 0.5 mol. The emission spectrum showed the most intense peak was located at 615 nm, which corresponds to the 5D0→7F2.transition of Eu3+ and that Eu3+ occupied the lattice site of noncentrosymmetric environment in the scheelite phases. The excitation spectrum displayed that these phosphors could be effectively excited by ultraviolet (UV) (396 nm) and blue (466 nm) light, nicely in correspondence with the widely ap- plied output wavelengths of ultraviolet or blue LED chips. The influence of flux on the luminescent properties of LiEu0.5Y0.5(WO4)0.5(MoO4)1.5 phosphor was analyzed. The XRD spectra indicated that the flux could help to crystallize the phosphor, and no other phases were formed except the tetragonal. When adding flux, the relative intensity of LiEu0.5Y0.5(WO4)0.5(MoO4)1.5 became much stronger and the average particle size of the phosphor decreased.

关键词： red emitting phosphor LiEu1-xYx(WO4)0.5(MoO4)1.5 flux white LED

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