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Table of Content

    24 May 2002, Volume 23 Issue 5
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    Articles
    Purification and Characterization of A113 Species
    ZHAO Hua-Zhang, LUAN Zhao-Kun, SU Yong-Bo, WANG Shu-Guang
    2002, 23(5):  751-755. 
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    The polynuclear Keggin species, AlC4Al12(OH)24(H2O)127+(Al13),was firstly separated and purified from polyaluminum chloride (P AC) by the precipitation method, which involved adding ethanol and acetone continuously to the PACsolution.The solid Al13 obtained with excellent dissolubility was characterized by Al-Ferron timed complexation spectrophotometry, 27A1 NMRspectroscopy, SEM, TEM and XRD.The results show that the components of PAC would be separated out in soluble sequence from low to high when ethanol and acetone were added continuously to the PACsolution, and that Al with a high purity would be obtained by taking out the middle precipitate.From Al-Ferron timed complexation spectrophotometry and 27A1 NMR spectroscopy, it was found that the sample obtained contained more than 95% of Al13.The SEM and TEM results showed that the small Al13 aggregates were about 200 nm and the big one were about 2 um in diameter.The Aln aggregates were mainly polyhedron such as prism, monoclinic rectangle and tetrahedron in solid sample and showed a branch type in solution.In the XRD spectra, the signal of Al13 appeared in the range of 2θfrom 5°to 25°
    Synthesis of Novel Metalloporphyrins and Their Biological Activityas Mimics of Enzymes
    LI Zao-Ying, ZHANG Yue-Ning, ZHU Xun-Jin, FENG Qing
    2002, 23(5):  756-762. 
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    Based on 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin(2),a series of non-water soluble and water-soluble metalloporphyrins were synthesized.As mimics of SOD (superoxide dismutase) and CAT(catalase) enzymes, metalloporphyrins 3a-3e, 5a-5f,and 8a-8f, were tested in the assays to dismutase O2-, to decompose H2O2,to clear OH,and to eliminate lipid peroxidation produced in the ho-mogenated livers of mice.Among these metalloporphyrins, 8a-8f, were most effective.Some rules were obtained from the biological activity testing results.
    NMR Study of ATP Binding Site with Cd2+
    JIANG Ling, MAO Xi-An
    2002, 23(5):  763-767. 
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    In this paper, the binding site of Cd2+ at the purine ring of ATPwas studied by using NMRtechnique.The changes of :H, 15Nand 31Pchemical shifts and 31P-31Pcoupling constants due to the presence of Cd2+ and the change of 113Cd chemical shift due to the presence of ATPin a wide pHrange are measured.It is found that, when pH>4.5, ATPchelates Cd2+ with its phosphate and N7; at pH 2.5—4.5, ATP binding sites are mainly phosphate and Nl, but phosphate/N7 mode still exists; when pHis very low (pH<2.5), ATPdoes not interact with Cd2+.
    Luminescence Study of Flouorescent Dye Impregnated into Si-based Nanoporous Alumina
    YANG Yang, LI Han-Ying, CHEN Hui-Lan, BAG Xi-Mao
    2002, 23(5):  768-771. 
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    Si-based nanoporous alumina can be used as the host matrices for a variety of luminescent media to obtain light dots in nanometer size.In this experiment three kinds of fluorescent dyes are impregnated into Si-based nanoporous alumina and utilized to obtain blue, green and red emission at room temperature.The blue-shift of emission spectra is found and the interaction mechanism between the fluorescent dye and the host matrices such as nanoporous alumina and porous silicon is discussed.The results show that the PLproperties of fluorescent dye are directly affected by the PLmechanism of the host matrices.
    Studies on Synthesis Conditions of Maximum Aluminum X(MAX)
    JIANG Hua, TANG Wei, ZHAO Bi-Ying, XIE You-Chang
    2002, 23(5):  772-776. 
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    Low-silica X, especially Maximum Aluminum X(so called for its lowest molar ratio SiO2 to Al2O3 are promising for their prospects of application.We synthesized MAXand studied its synthesis conditions.The results showed that the most appropriate ageing temperature was 70 ℃ and ageing time was 6 h.Ageing temperature not only played an important role in shortening the overall time of the synthesis, but also determined the purity of products by influencing the types of nuclei formed during the induction period.Pure MAX could be obtained only within a rather narrow range of composition.The experiments showed that the mother liquid was easily reusable as alkaline source which made the manufacture of MAX more economic and environment-friendly.
    Synthesis, Anti-HIV-1 Activity and Toxicity of New Rare Earth-containing Heteropoly Blues
    LIU Shu-Xia, LI Yang-Guang, HAN Zheng-Bo, WANG En-Bo, ZENG Yi, LI Ze-Lin
    2002, 23(5):  777-782. 
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    Two- and four- electron heteropoly blues of samarium-containing polyoxotungstosilicate, poly-oxotungstogermanate, polyoxotungstophosphate and polyoxotungstoarsenate with Keggin structure have been 'synthesized, stoichiometrily determined by elemental analyses and cerimetric titration, and characterized by IR, UV-Vis, 183W NMR and ESR spectra.The anti-HIVactivities and toxicities of these compounds have been determined in human Tlymph cells MT-4.It has been found that the four-electron heteropoly blue of samarium-containing polyoxotungstogermanate (HPBR-2) has a high therapeusis index.Medicine tolerance test shows that the cells have no obvious resistance to HPBR-2.The half-inhibition concentrations IC50 of HPBR-2 to acutely infected MT-4 cells have no distinct difference between generation 0 and generation 9.The acute toxicity and Ames test of HPBR-2 have also been carried out.HPBR-2 can not mutate the bacterium typhosum.The half toxicity dose LD50 of HPBR-2 orally administrated to mice is 2988 mg/kg and the maximum tolerance dose is 800 mg/kg, which is 2000 times as high as the dose orally administrated to the human being(20 mg/50 kg).HPBR-2 belongs to one of the complexes with high safety factors.
    Hydorthermal Synthesis and Characterization of a New Compound [Co(en)3]2·2H3O·[As8 V14O42(HPO4)]·2H2O
    LI Ya-Feng, CUI Wei, WU Gang, FANG Qian-Rong, ZHU Guang-Shan, LI Bin-Song, GAO Fei-Fei, WANG Chun-Lei, QIU Shi-Lun
    2002, 23(5):  783-785. 
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    In this paper, a new compound [Co(en)3]2·2H3O·[As8V14O42(HPO4)]·2H2O was obtainedby hydrothermal method at 140℃ for 5d, which was characterized by IR, ICP and single crystal X-raydiffractinn.The titled compound is crystaIlized in orthomgonal system, space group Pbca with a= 2.4825(9) nm, b=2.0994(8) nm, c=2.8866(9) nm, V=15.009(9) nm3, Z=8, Dc=2.289 Mg/m3, Mr=2586.19, μ= 5.703 mm-1, F(000) = 9788, R=0.0889, wR=0.2482.The tetrahedron PO4 is in-cluded in an anion cage which is formed via condensed vanadium oxygen square pyramids(VO5) and octa-hedral(VO6) connected by As2O5 units through sharing oxygen atoms.The two Co cation is coordinatedby three en respectively, in which the six Natoms of the three en form an octahedron with Co atom as thecentre.
    Inclusion and Illuminant Property of Eosin Y into Mesoporous Molecular Sieve MCM-41 Film and Powder
    BAI Ni, ZHANG Ping, GUO Yang-Hong, LI Shou-Gui, PANG Wen-Qin, LUO Wei, ZOU Guang-Tian
    2002, 23(5):  786-788. 
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    In this paper, Eosin Yhas been successfully incorported into mesoporous molecular sieve MCM-41 film and powder by Co-assembly method, then the composite have been characterized by XRD, UV-Vis diffuse reflection spectra.Moreover, the illuminant properties have been examined.
    Synthesis, Structure and Magnetic Properties of the Sandwich-type Tungstoarsenates Containing Tetrametallic Cluster[M4(H2O)2(AsW9O34)2]10-(M=CuⅡ,CoⅡ,MnⅡ, NiⅡ, ZnⅡ).
    BI Li-Hua, HUANG Ru-Dan, PENG Jun, WANG En-Bo
    2002, 23(5):  789-791. 
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    The compounds [M4(H2O)2(AsW9O34)2]10-(M=CuⅡ,CoⅡ,MnⅡ, NiⅡ, ZnⅡ) were synthesized and characterized by IR, UV, elemental analysis and magnetic measurements.These compounds are isostructural to the Pderivatives and comprise a rhomb-like M4O16 group encapsulated between two fragments of the trivacant Keggin polyanion [AsW9O34]9-.The crystal structures of the MnⅡ and CuⅡ derivatives were compared with that of the Pderivatives.The MnⅡ derivative exhibits antiferromagnetic Mn-Mn exchange interactions and S=0 ground state.
    Fluoroimmunoassay of Estradiol Based on the Thermo-sensitive Hydrogel
    WANG Yong-Cheng, ZHANG Xin-Xiang, LI Yuan-Zong, CHANG Wen-Bao
    2002, 23(5):  792-795. 
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    An indirect competitive fluoroimmunoassay of estradiol was developed based on the thermo-sen-sitive hydrogel, poly-JV-isopropylacrylamide(pNIPA).Antigen was conjugated to pNIPAto form antigen bound thermally reversible hydrogel (pNIPA-Ag) after the antigen was synthesized by covalent bonding estradiol to bovine serum albumin.The anti-estradiol monoclonal antibody (McAb) was prepared by an in vivo method with McAb secreting hybridomas.Fluorescein isothiocyanate(FITC) labeled McAb(McAb-F) was prepared by bonding FITCto purified McAb.Then free estradiol reacted with limited amount of McAb-Fcompeting with pNIPA-Ag.Separation of the immune complex, pNIPA-Ag-McAb-F, was carried out by centrifuging and precipitating at a temperature above critical solution temperature of the hydro-gel.After the above immune complex was dissolved, the fluorescence intensity was measured by a Hitachi M-850 fluorospectrometer.The calibration curve of free estradiol covered a range of 10-625 ng/mL, and the detection limit of the presented method for free estradiol was 3.2 ng/mL.The cross-reactions and the recoveries of the immunoassay were also investigated.
    Application of Dyadic Wavelet Transform Modulus Maximum Method to Denoising of Capillary Electrophoresis Signals
    ZHONG Hong-Bo, LI Guan-Bin, LIU Hui, ZHENG Jian-Bin, CHEN Li-Ren
    2002, 23(5):  796-800. 
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    In this paper, a dyadic wavelet transform modulus maximum de-noising method, which is based on the fact that the characteristics of wavelet transform modulus maximum of real signals are distinctively different from those of noises, was founded.The effect of the full width at half-maximum and noise quantum was investigated, and the selection of threshold was discussed.Finally, the method was applied to capillary electrophoresis signals.The experimental results show that this method can be used to pick up real signal and de-noise effectively.
    High Frequency Conductivity Detector for Capillary Electrophoresis
    CHEN Zuan-Guang, MO Jin-Yuan
    2002, 23(5):  801-804. 
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    A high frequency conductivity detector for capillary electrophoresis was designed based on the principle of high frequency titration.In this detector, two tubular electrodes were placed outside the separation capillary.The results of various influence factors could be explained theoretically.The good detection conditions were 0.5—1.5 mm of distance between the two electrodes, and 20—50 kHz of frequency.LODreached about 10-6 mol/L.The detector can be used to detect all charged analytes and avoid poisoning of electrodes.
    Identification of the Flavonoid Constituents from Leaves of Acanthopanax Senticosus Harms
    CHEN Mao-Lian, SONG Feng-Rui, GUO Ming-Quan, LIU Zhi-Qiang, LIU Shu-Ying
    2002, 23(5):  805-808. 
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    Four flavonoids from leaves of Acanthopanax Senticosus Harms were observed in negative ion mode in the electrospray mass spectra.Two of them were further isolated and identified as quercitrin (quercetin-3-O- -L-rhamnoside) and hyperin (quercetin-3-O- -D-galactoside) on the basis of MSn and NMR data.The other two compounds in the mixtures were tentatively established as quercetin and rutin ( quercetin-3-O-rutinoside) in terms of their electrospray tandem mass spectrometry (ESI-MSn) data.Three of the four flavonoids (excluding hyperin) haven't been reported in this plant before.
    Accelerator Mass Spectrometry Studies on Adduction of Nicotine with Hemoglobin and Serum Albumin in Mouse
    WANG Yan, WANG Hai-Fang, SUN Hong-Fang, WANG Xiang-Yun, LIU Yuan-Fang, LIU Ke-Xin, LU Xiang-Yang, MA Hong-Ji, LI Kun
    2002, 23(5):  809-812. 
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    Adducts of hemoglobin(Hb) and serum albumin(SA) with nicotine in mouse blood were mea-sured respectively by using accelerator mass spectrometry (AMS).The dose response of adduct levels ofHb/SAand the correlative relationship between the two blood protein adducts were investigated over arange of doses(0.1-100.0 μg/kg body weight), which were equivalent to a low-level dose of environ-mental exposure of cigarette smoking.Both the levels of Hb and SAadducts increased with increasing doseand showed a linear relationship.By plotting Hb/SAadducts versus DNAadducts, a linear relationship fitsthe experimental observations best, which means that Hb/SAadduct could substitute for DNAadduct as abiomarker for nicotine.The detection limit of protein adduct in this work is 0.03 pmol/g protein(namely3.2 adducts/1012 amino acid residues), the excellent sensitivity in protein biomarker measurements com-pared to the data reported previously.
    Non-uniform Field Theory in Electrostacking
    YANG Li, HE You-Zhao, CAN Wu-Er, LIN Xiang-Qin, ZHAO Yao-Qiang
    2002, 23(5):  813-817. 
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    According to the electric poential distribution of a non-uniform field in a sample solution, a the-oretical model of the non-uniform electric field, namely, a pair Of equal and opposite charges separatedfrom each other in a distance, was used to investigate the non-uniform field electrostacking.The effect ofthe non-uniform field on electrostacking was presented in this paper.In order to validate the theoreticalmodel, anionic chromium(Ⅵ ) and cationic lead (Ⅱ ) in mineral water were pre-concentrated with an im-proved non-uniform field electrostacking system simultaneously.And the experimental results were coinci-dent with the theoretical prediction.
    Studies on a New Method of Extraction and Purification of Troponin Ⅰ
    MA Xue-Hua, LIU Zhong-Ying, HU Xiu-Li, SHI Yi, JIANG Xi-Luo, AN Ru-Guo
    2002, 23(5):  818-821. 
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    Rabbit skeletal muscle was homogenized and centrifuged, then applied to DEAE-Sephadex A25, Sephadex G75 and Butyl Sepharose columns in turn.Finally, the purified sTnCwas obtained.The affinity chromatography gel was prepared by binding the purified sTnConto the CNBr-act Sepharose 4B.Troponin Iwas isolated directly from whole skeletal and cardial muscle by using the affinity chromatography gel.Both the results of HPLCand SDS-PAGEshow a single band.The molecular weights of the purified sTn Iand cTn Iwere 21000 and 25000, respectively.The yield of sTnCwas 82.6 mg/100 g cardiac tissue, which was higher than that obtained by using the previous method.In this work, 91.6 mg purified cTn Iwere obtained.
    Binary Chiral Selectors for Capillary Electrophoretic Enantioseparation of Amino Acids Derivatized with Fluoresceine Isothiocyanate
    LU Xiao-Ning, CHEN Yi
    2002, 23(5):  822-824. 
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    A novel capillary electrophoretic approach has been developed for the enantioseparation of aminio acids derivatized with fluoresceine isothiocyanate(FITC).The detection was performed with laser-induced fluorescence.Binary chiral selectors of -cyclodextrin( -CD) and sodium taurocholate(STC) were used and it was found that the resolution and enantioselectivity are superior to either -CDor STCused alone.The optimum molar ratio of -CDto STCis 23 at a total concentration above 20 mmol/L.The best running .buffer tried is 80 mmol/Lborate at pH = 9.3.In this work, all of the 20 pairs of amino acid enantiomers tested were baseline resolved with a resolution greater than 1.9 of which 17 pairs gave a resolution above than 3.0.The highest resolution reached 14.58.
    Langmuir Aggregation of Chromophore in Protein Macromoleculeand Its Application──Interaction of Phloxine B with Proteins
    GAO Hong-Wen, CHEN Yun-Sheng
    2002, 23(5):  825-827. 
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    The microphase adsorption-spectral correction(MASC) technique was applied to investigation ofthe interaction of phloxine B(PB) with proteins.The aggregation of PBobeys the Langmuir monolayeradsorption and it has been used in the determination of protein solution at pH3.8.The results show thatthe adsorption ratios of PBto proteins are n(PB)∶ n(BSA) = 1:155, n(PB):n(OVA) = 1:58, n(PB):n(Mb) = 1:18, their adsorption constants are 2.17 × 104, 1.18 × 104, 3.25× 105 and their real molarabsorptivities εBSA-PB555nm=7.94 × 106, εOVA-PB555nm=3.39× 106, εMb-PB555nm= 1.21 × 106 L ·mol-1 ·cm-1.The interac-tion of PBwith proteins is sensitive and selective in the presence of EDTA.For analysis of samples, the re-covery of protein is between 96.7% and 107% and the relative standard deviation 4.6%.
    Theoretical Study of Photochemical Chlorination of Pyridine in Gas Phase──Transition States of Addition Mechanism and IRC Analysis
    HAD Jin-Ku, YANG En-Cui, WANG Wan-De, ZHAO Xiao-Jun, CAO Ying-Yu, HAN Xiao-Yan
    2002, 23(5):  828-831. 
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    The addition mechanism of pyridine reacting with chlorine radical was studied theoretically bysemi-empirical method PM3.The results show that there exist two transition states on each reaction pathof obtaining 2-chloropyridine, 3-chloropyridineopyr and 4-chloropyridine.The energies of chief transitionstate and activation barrier for leading to 2-chloridine are the lowest among the three reaction paths, whichare -110293.6 and 139.2 kJ/mol respectively, so 2-chloropyridine is obtained priorly.On getting 2-chloropyridine, from the variation of bond length, bond order and net charge, we can concludde that theformation of C－Cl is concerted with the breaking of conjugated double bond, and the break of C-Hisconcerted with the reconformation of conjugated double bond Both inductive and resonance effects can in-fluence the net charge of chlorine atom.
    Synthesis, Characterization and Spectrum Property of a New Red-Fluorescence Porphine
    QUO Can-Cheng, YIN Zhen-Ming, ZHU Jin-Tao, NI Rong
    2002, 23(5):  832-834. 
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    A new polyarylaminophenylporphine, tetra(p-N,N-diphenylamino)phenylporphine(TDPAPPH2) was synthesized by direct condensation of pyrrole and p-N, N-diphenylaminophenyl alde-hyde.Its molecular structure was characterized by elemental analysis, 1H NMR, IRand UV-Vis spectra.Compared with trtraphenylporphine (TPPH2) and tetra (p-`amino) phenylporphine (TAPPH2), the absorption and emission peaks of TDPAPPH2 had large red-shifts due to the changes of LUMO and HOMO levels.
    Preparation and Evaluation of Octadecyl-Zirconia Bonded Stationary Phases
    YANG Jun-Jiao, WANG Hui, ZUO Yu-Min
    2002, 23(5):  835-838. 
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    Porous zirconia particles, synthesized by polymerization-induced colloid aggregation (PICA)method, were modified with octadecyltrimethoxysilane compounds for reversed-phase high-performanceliquid chromatography.These stationary phases were evaluated in terms of reversed-phase chro-matographic properties with different volume ratos of methanol to water.Stability studies conducted at anextreme pH (pH = 2.0 and pH = 12.0) have shown that octadecyl-zirconia sorbents are no more stablethan ODSunder acidic conditions, but rather stable under basic conditions.The retention of non-polar andslightly polar compounds was quasi-homoenergetic on octadecyl-zirconia stationary phases.
    Chemistry and Applications of Phosphonium and Arsonium Ylides(ⅩⅩⅨ)──Studies on the Hydrolysis of Arsonium Ylides Containing Perfluoroalkyl Group andSynthesis of2-Pyranone Derivatives
    CAO Wei-Guo, DING Wei-Yu, WANG Li-Yan, SONG Li-Ping, ZHANG Qian-Ying
    2002, 23(5):  839-842. 
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    In the presence of K2CO3, reaction of (2-naphthoyl)methyl arsonium bromide (1) with methyl2-perfluoroalkynoates(2) in methylene chloride at room temperature afforded the adduct methyl4-(2-naphthoyl)-2-triphenylarsoranylidene-3-perfluoroalkyl-3-butenoates(3) as major product and 4-(2-naphthoyl)-4-triphenylarsoranylidene-3-perfluoroalkyl-2-butenoat.es (4) as minor product in high yield.Hydrolysis of compound 3 in V(CH3OH):V(CH2O) = 9:1 methanolic solution at 80 in a sealed tube,4-perfluoroalkyl-6-(2-naphthyl)-2-pyranones(5) was obtained in an excellent yield.The catalytic hydroly-sis of compound 3 with silica gel and the mechanisms for the formation of the products will also be discuss-ed.
    Progress of Research on Magnetic Coupling System Including Nitronyl Nitroxide Radicals
    LIU Zhi-Liang, LIAO Dai-Zheng, JIANG Zong-Hui
    2002, 23(5):  843-848. 
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    The structure characteristics and the magnetic interaction mechanism of magnetic coupling sys-tem including nitronyl nitroxide radicals and "metal-radical" molecular magnets are introduced.The futuredevelopment aspects of research about the field are proposed.
    Studies on Tetraorganodistannoxane-catalyzed Esterification
    Lü Yan, LAN Zhi-Li, LI Jing, XIE Qing-Lan
    2002, 23(5):  849-851. 
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    1,1,3,3-Tetraorganodistannoxanes are a sort of organotinoxo clusters.They show an excellentcatalytic activity in organic synthesis because they have unique dimeric ladder structures that contain twokinds of five-coordinated tin atoms.Despite of involving a metalloxane core, the distannoxane is quite solu-ble in organic solvents.This is attributable to the double-layered structure of the distannoxanes in whichthe surface alkyl groups prevent the inorganic core from being exposed to the solvent phase.In this articletetraorganodistannoxane-catalyzed esterification of acetic acid and w-butanol was studied.Various cata-lysts,different proportions of acid and alcohol and dosages of catalysts affected this reaction.The mecha-nism of tetraorganodistannoxane-catalyzed esterification is also discussed.
    Synthesis and Characterization of Phosphoangiotensin Ⅱ
    LUO Shi-Zhong, ZHAO Gang, LI Yan-Mei, XU Li, ZHAO Yu-Fen
    2002, 23(5):  852-854. 
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    The reversible phosphorylation/dephosphorylation of protein is probably the most common andimportant regulatory modification of proteins.Synthesis and identification of phosphopeptide have beenshown to have dramatic agonist effects in several signaling pathways.The phosphoangiotensin Iwas syn-thesized with two different strategies: global approach and building block approach.The building block ap-proach using phosphorylation regeants di-tert-butyl-N,N-diethyl phosphoramidite is the preferred methodfor the synthesis of peptides containing phosphotyrosine.The phosphoangiotensin and angiotensin were easily distinguished by ESI-MS.It may be useful to determining the phosphrylation sites of peptidescontaining multi-phosphorylated tyrosines by multi-stage mass.The phosphorylation of angiotensin Ide-creases the content of-helix and increases the contents of -turn.
    Highly Stereoselective Synthesis of (2E,4E)-Tetradecadienal by Isomerization of α,β-Tetradecynic Aldehyde
    ZHENG Ke-Li, WANG Gui-Jie, YUAN Gu
    2002, 23(5):  855-856. 
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    (2E,4E)-Tetradicadienal was synthesized by the isomerization reaction of,-tetradecynaldehyde under catalyzing of triphenylphosphine.
    The Effect of La Doped on V2O5/γ-Al2O3 Catalyst for Activity in the Dehydrogenation of Isobutane
    MA Hong-Chao, LIU Zi-Yu, WANG Zhen-Lu, ZHU Wan-Chun, WANG Guo-Jia
    2002, 23(5):  857-860. 
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    V2O5/γ-Al2O3 is a new catalyst for the isobutane dehydrogenation.It was found that the dehy-drogenation activity of catalysis and the action of coke can be improved by adding appropriate La.Thestructure and surface state of La-doped V2O5/γ-Al2O3 catalysts were characterized by FTIR, BET, TG,TPRand TPR.The result showed that the changes of dispersion and reduction property of active compo-nents were quite obvious after adding La.
    Kinetics Study on Catalytic Dehydrogenation of Cyclohexanol
    ZHANG Ming-Hui, LI Wei, GUAN Nai-Jia, TAG Ke-Yi
    2002, 23(5):  861-865. 
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    A continuous flow fixed bed reactor was used to study the heterogeneous catalytic reaction ki-netics for dehydrogenation of cyclohexanol.The kinetic parameter of power velocity model was calculatedand the reaction's apparent activation energy Ea, was equal to 44.28 kj/mol.The velocity-controlling mod-els were derived from self-equilibration method, and the model's parameter and the material's adsorptionenthalpy were calculated.The results showed that the models based on adsorption of cyclohexanol and sur-face reaction were correlated.The results of variance and residual error showed that the error was in therange of kinetic toleration, and the experiment did not have any system error.The velocity-controllingmodel based on surface reaction had a relatively minimal error.
    Heterogeneous Catalysis Reaction Between Carbon Disulfide and Atmospheric Particles
    WANG Lin, ZHANG Feng, CHEN Jian-Min
    2002, 23(5):  866-870. 
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    The formation of carbonyl sulfide(COS) by catalytic oxidization of carbon disulfide (CS2) overatmospheric particle catalysts was explored through FTIR, MSand a fixed bed stainless steel reactor.XPSwas used to analyze the surface elements on the catalysts.Also the crystallizing conditions and specific sur-faces (areas) of the catalysts were investigated by means of XRDand BET.Some oxides such as CaO,Fe2O3, A12O3 and SiO2 were investigated under the conditions similar to those for the investigation of atmo-spheric particles as a comparison.The results showed that the atmospheric particles and the oxide catalystsexhibited considerably oxidizing activity for CS2 at ambient temperature to form COS.The adsorb activeoxygen over the catalysts' surfaces is the major reason for this reaction.Amodel was given to explain themechanism on the heterogeneous catalysis reaction.And elemental sulfur as well as COS was one of themain products, even CO2 could be produced by a secondary reaction on some catalysts.SO42- could be pro-duced by further oxidation of active elemental sulfur.
    Investigation on Photocatalytic Oxidation Degradation of n-C7H16 over ZnO Ultrafine Particles
    JING Li-Qiang, XU Zi-Li, DU Yao-Guo, SUN Xiao-Jun, WANG Ling, ZHOU Xiu-Qing, SHAN Hong-Yan, CAI Wei-Min
    2002, 23(5):  871-875. 
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    The degradation of gas-phase n-C7H16 by the technique of photocatalytic oxidation on ZnO wasinvestigated.It was found that under a certain condition of reaction, the photocatalytic oxidation degrada-tion rate of n-C7H16 on ZnO ultrafine particles (UFP) was higher.The influences of some factors such as O2 volume fraction and H2O(g) volume fraction on photocatalytic oxidation of n-C7H16 were studied.The gascomposition during photocatalytic oxidation of n-C7H16 was qualitatively analyzed by using gas chromatog-raphy (GC ) and gas chromatogram-mass spectrum (GC-MS), and the principal intermediate product,propanal, was quantitatively analyzed, which could demonstrate that the most part of n-C7H16 degraded byphotocatalytic oxidation on ZnOwas oxided to CO2. In addition, the kinetics and mechanism of photo-catalytic oxidation reaction of n-C7H16 were also probed into.
    Theoretical Studies of the Mechanism and Energetics for the Reactions of Transition Metal Ions with Alkanes──H2 Elimination Mechanism in the Reaction of Ni+(2D) with Propane
    ZHANG Dong-Ju, ZHANG Chang-Qiao, LIU Cheng-Bu
    2002, 23(5):  876-879. 
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    The reaction of Ni+ with propane have been studied extensively by using density functional theory,and the detailed information regarding the mechanism and energetics of H2 elimination on the potential energy surface of [Ni,C3,H8]+ have been obtained at B3LYP/6-311 + +G(3df/,3pd) level.Both the initial primary or secondary C—H bond activations in propane mediated by Ni+ in the reaction of Ni+ with propane can result in the H2 elimination from Ni(C3H8)+ .Five intermediates, two C—H bond activation transition states and three H-shift transition states are located on this potential energy surface.The heat ofreaction for Ni++C3H8→Ni(C3H6)++H2 is calculated to be 142.28 kj/mol.This result is in goodagreement with the experimental finding, a value of 127.85 kJ/mol at 0 K.
    Electronic Structures of Si- and Ge-phthalocyaninato Polymers
    HUANG Yuan-He, SUN Xiao-Li, LI Yu-Xue, LIU Ruo-Zhuang
    2002, 23(5):  880-883. 
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    SCF-CNDO/2-COmethod is used to study the band structures and electronic properties of one-dimensional phthalocyaninato (Pc) polymers [MPcX]n,(M=Si, Ge ; X=O, S).It has been discussed that the electronic properties vary with the kinds of atoms and the staggering angle θ between neighboring rings.The calculated results show that the variation of the staggering angle θ has not any strong effect on electronic properties of polymers except for the frontier bandwidth.The analysis of crystal orbitals shows that in [MPcO]n conduction pathway of charge-carrier is mainly composed of the overlaps of π orbitals of phthalocyanine ring; while in [MPcS]n, the electrons in conduction band can also move along the polymer chain through the d-orbital overlaps of central and bridge atoms.
    Theoretical Study on the Reaction Path and Varitional Rate Constant of Reaction H+CH3NO2→H2+ CH2NO2
    JI Yong-Qiang, FENG Wen-Lin, XU Zhen-Feng
    2002, 23(5):  884-887. 
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    Using ab initio theory, the geometries of the reactants, transition state, and products of the reaction H+CH3NO2 H2+CH2NO2 have been optimized at the UMP2(full)/6-31lG** level.The forward and reverse reaction potential barriers are 82.73 and 57.14 kJ/mol respectively.The reaction, that is the formation of H—H bond and breaking of C—H bond, has been shown by a coordination process.Furthermore vibration normal-mode are discussed along the IRC, it is clear that there is a reactivity normal-mode which leads the reaction from reactants to product.The forward reaction theoretical rate constant, obtained by using the variational transition-state theory (CVT), are consistent with experimental value at the reaction temperature 1000—1400 K.
    Theoretical Studies on the Structure and Stability of B2F2 Molecule
    YU Hai-Tao, HUANG Xu-Ri, CHI Yu-Juan, FU Hong-Gang, DING Yi-Hong, LI Ze-Sheng, SUN Chia-Chung
    2002, 23(5):  888-892. 
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    The structure and stability of B2F2 molecule have been predicated by means of ab initio molecular orbital methods.The results show that the linear FBBF that has D∞h symmetry and 3Σg electronic state is the most stable isomer.The F—B and B—B bond distances are 0.12942 and 0.14820 nm at UCCSD(T, full)/6-311 + G(2df) level of theory, respectively.The vibrational frequencies appear at 1860.00 cm-1 and 1320.62 cm-1.The dimerization enthalpy of BF(1Σg+) and vertical ionic potential of the linear FBBFat UQCISD(T,full)/6-311 + G(2df)// UMP2(full)/6-311G(d)+ ZPVElevel of theory are 59.86 and 848.58 kJ/mol, respectively.
    Theoretical Studies on TiP6+ and Ti2P6+ Binary Clusters
    PAN Ge-Bo, FENG Ji-Kang, REN Ai-Min, HAN Chun-Ying, GAO Zhen
    2002, 23(5):  893-896. 
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    The possible geometrical structures and relative stability of titanium/phosphorus binary clusters of TiP6+ and Ti2P6+ are explored by means of density functional theory (DFT) quantum chemical calculations The effects of polarization functions and electron correlation are included in these calculations.The results show that the most stable structures of TiP6+ and Ti2P6+ belong to the C3v and D6h point group respectively.Our forecast to the properties of the clusters is in good agreement with the experimental results.
    Catalytic Reduction of SO2 and NO by CO on Rare Earth Oxides(Ⅲ)──Simultaneous Reduction by Using CO as Reducing Agent
    WANG Lei, MA Jian-Xin, XIE Min-Ming, ZHANG Yi-Qun, ZHOU Wei
    2002, 23(5):  897-901. 
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    Rare earth oxysulfides obtained from the activation of rare earth oxides were effective catalysts for the simultaneous reduction of SO2 and NO by COto elemental S.The most active catalysts were Sm2O2S and Nd2O2S, over which a conversion of >95% for both SO2 and NO was obtained at 475 .Exceptional behavior was observed over CeO2,which showed a low activity for desulfurization, but a high activity for denitrification.The seperating experimental results showed that GOS was an intermediate not only for the reduction of SO2 by CO but also for the reduction of NO by CO.Thus, a COSintermediate mechanism was proposed to describe the simultaneous reaction.Based on the mechanism, the difference a-mong the activities of the rare earth oxides was discussed.
    Correlation of Performance and Structure of Supported Rhenium Catalysts for Methanol Selective Oxidation
    YUAN You-Zhu, CAO Wei, TSAI Khi-Rui, IWASAWA Yasuhiro
    2002, 23(5):  902-905. 
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    Supported Re catalysts were prepared by impregnation of ammonium perrhenate precursor on oxide supports, followed by calcination at 673 Kin He steam.Iron-oxides and V2O5 supported Re catalysts showed a higher activity and selectivity for the catalytic methanol oxidation to dimethoxymethane [3CH3OH + (1/2)O2 CH2(OCH3)2 + 2H2O].The selectivity was as high as 90—94% (molar fraction) at 513 K.The highest reaction rate of 450 mmol·h-1·g-1 Re on -Fe2O3 supported Re catalysts was achieved with the Re loading weight of 2%(mass fraction).The reaction rate gradually decreased with the increase of Re loading weight.Calcination of ammonium perrhenate alone at 673 Kin He gave mono-clinic ReO2 as a main product.However, the application of the iron-oxide may prevent Re7+ from reducting to Re4+ during the calcination at 673 Kin He in the case of proper Re loading weight probably through the interaction of ammonium perrhenate with the supports, leading to the growth of Re6+ on the catalyst surface.Above the monolayer loading weight of ReO3, there was coexistence of Re6+ and Re4+ on the catalyst surface.Aredox mechanism between Re6+ and Re4+ species on the catalyst surface was proposed to be responsible for the high performance in the methanol selective oxidation to dimethoxymethane.
    Kinetics Studies on Quenching of CCl2CA1B1 and a3B1 by O2, CF4 CF2Cl2,CH3NO2,CH2Br2 and Chloromethane
    GAO Yi-De, HU Chang-Jin, CHEN Yang, DAI Jing-Hua, CHEN Cong-Xiang
    2002, 23(5):  906-909. 
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    CCl2 free radicals were produced by dc discharge of CCl4(in Ar).Ground electronic state CCl2 radical was electronically excited to A1B1(0,4.0) state k=0 level with Nd YAGlaser pumped dye laser at 541.52 nm.Experimental quenching data of CCl2(A1B1 and a3B1) by O2, CF4, CF2Cl2, CH3NO2, CH2Br2 and chloromethane were obtained by observing time resolved fluorescence from the excited CCl2 radicals transition, which showed a superposition of two exponential decay components.The state-resolved rate constants KA and Ka were acquired by analyzing and dealing with these data by using a three-level-model.
    Grand Canonical Ensemble Monte Carlo Simulation for Determination of Pore Size of Activated Carbon
    CAO Da-Peng, WANG Wen-Chuan
    2002, 23(5):  910-914. 
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    A grand canonical Ensemble Monte Carlo (GCEMC) simulation for determination of pore width of activated carbon has been carried out by using the adsorption of methane in activated carbon at 299 K.In our GCEMCsimulation, Non-polar methane molecule is modeled as a spherical Lennard-Jones molecule.Activated carbon is modeled as slit pores and the 10-4-3 potential is used for the description of the interaction between methane and a slit pore in the GCEMC simulation.In the simulation, by adjusting the parameter of pore size,the adsorption isotherms of different pore widths are obtained.Compared with experiment data of methane adsorbed in activated carbon, based on the statistical integral equation, the average pore width of activated carbon is solved, which indicates that a combination of GCEMC method and statistical integral equation is a new and useful tool for investigating the pore size distribution or the average pore width of macro-pore material.
    Thermoregulated Phase-transfer Ligands and Catalysis(ⅩⅥ)──Kinetics Investigation of CO Selective Reduction of Aromatic Nitro Compounds Catalyzed by Rh/PETPP in Two-phasic System
    MEI Jian-Ting, JIANG Jing-Yang, WANG Yan-Hua, WU Xiao-Wei, JIN Zi-Lin
    2002, 23(5):  915-918. 
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    The nonionic water-soluble phosphine ligand P[C6H4-p-(OC2H4)6OH]3(PETP)/Rh complex termed the thermoregulated phase-transfer catalysis (TRPTC) was applied to CO selective reduction of ni-troarenes compounds in the aqueous/organic two-phase.Using o-ClC6H4NO2 as a substrate, the influences of the reaction temperature, COpressure, concentration of substrate, concentration of catalyst and volume ratio of aqueous to organic on the catalyst properties were studied.Under the conditions 423 K, pco=4 MPa and t = 32 h, the conversions of o-ClC6H4NO2 were 98% and the selectivity for the corresponding amine was higher than 99%.The kinetics investigation suggested that first-order dependence was observed for the effect of the concentration of catalyst and o-ClC6H4NO2. The apparent activation energy was 131.13 kJ/mol.
    Laser Stimulated Oxidative Dehydrogenation of Isobutane to Isobutene on the Surface of Pb and Bi Phosphate
    ZHONG Shun-He, GENG Yun-Feng, TAO Yue-Wu
    2002, 23(5):  919-922. 
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    Pb3(PO4)2 and BiPO4 were prepared by the precipitation method.The surface composition, structure, chemisorption properties and the behavior of laser stimulated isobutane selective oxidation were investigated by means of the techniques of XRD, IR, TPDand LSSR.The results showed that both Lewis base sites, O2- on the surface P＝O　or Pb(Bi)—O bonds, and Lewis acid site, Pb2+ or Bi3+ appear on the surface of Pb3(PO4)2 or BiPO4. Two methyl hydrogens in isobutane molecule can be chemisorbed at the terminal oxygen of neighboring Lewis base sites P＝O bonds on the surface of phosphate.Under the conditions of 0.1 MPa and 200 with the 1056 cm-1 laser photons exciting the P＝O bonds for 1000 times, the oxidative dehydrogenation reaction of isobutane occurred remarkably with the product selectivity of isobutene over 95%.In the course of LSSR, the conversion of isobutane depends on the vibrational structure of the solid materials and the adsorbing amount of is obutane on the excited P ＝O bonds, the selectivity of the reaction product depends on the adsorbing state of isobutane on the solid surface.
    Selective Catalytic Reduction of NO with C3H6 on CuCl/MCM-41 Prepared by Disperse Method
    JIA Ming-Jun, LI Xue-Mei, WANG Gui-Ying, ZHANG Wen-Xiang, WU Tong-Hao
    2002, 23(5):  923-926. 
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    The selective catalytic reduction (SCR) of NOwith propene over CuCl/AlMCM-41 and CuCl/ AlMCM-41 catalysts prepared by dispersion method was studied.It was found that CuCl/AlMCM-41 exhibits a substantially higher catalytic activity over CuCl/SiMCM-41.And the function of copper species in these catalysts was also investigated by means of H2-TPR, IRand ESR.The results show that the copper ions (Cu2+and Cu+ ) coordinated with framework aluminium are a main active centre for SCRof NOover CuCl/AlMCM-41 catalyst, whereas in CuCl/SiMCM41 catalyst these kinds of copper ions could not been found.
    Growth of ZnO Film by Plasma-assisted MOCVD
    WANG Xin-Qiang, YANG Ru-Sen, YANG Shu-Ren, WANG Jin-Zhong, LI Xian-Jie, YIN Jing-Zhi, Ong H. C., JIANG Xiu-Ying, GAO Chun-Xiao, DU Guo-Tong
    2002, 23(5):  927-931. 
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    The growth of ZnO film by plasma-assisted MOCVD was reported in this atricle.From X-ray diffraction spectrum, the intensity of (0002) peak at 2θ=34.56°was high, indicating a c-axis orientation perpendicular to the substrate surface in ZnO.Ultraviolet(UV) emission with a high intensity at 375 nm was attributed to the excitation emission from photoluminescence (PL) spectrum.In PLspectrum, we also found green emission with a low intensity and wide FWHM.This green emission came from deep level transition due to defect levels in ZnO film.The ratio of the intensity of UVemission to that of green emission was as high as 193, indicating a high quality of the samples.This high quality was also confirmed by Atomic Force Microscope (AFM) analysis.Two methods were used in order to get ZnO film with a high resistivity.One was annealing ZnO film every ten minutes under relative high pressure of oxygen (O2) at 700,the other was N-doping by N2.ZnO film with a high resistivity was successfully prepared.The resistivity was 5×104Ω·cm and 1100Ω·cm, respectively, while that of untreated sample was as low as 0.65Ω·cm.Furthermore, N-doped sample had a higher resistivity and better photoluminescence properties than that of the sample obtained by annealing under oxygen.
    Preparation of YSZ Electrolyte Membrane Tube by Vacuum Casting and Its Application to Solid Oxide Fuel Cells
    HE Tian-Min, LU Zhe, LIU Han-Jun, YANG Jing-Dong, PEI Li, LIU Wei, HUANG Xi-Qiang, LIU Zhi-Guo, LIU Jiang, SU Wen-Hui
    2002, 23(5):  932-936. 
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    The dense yittria-stabilized zirconia membrane tube was prepared by using pyridine as dispersant by vacuum casting.The thickness of the membrane in the tube is 0.2 mm and the length is 140 mm.The effect of sintering temperature on the density and ionic conductivity of the samples was studied.The solid oxide fuel cell(SOFC) was made of the YSZmembrane tube, which was sintered at 1650 for 2 h.The electrochemical property of the SOFCwas studied from 500 to 900,hydrogen and city coal gas were used as fuel, respectively.The research shows that the YSZmembrane tube with a high quality and density can be prepared by the vacuum casting, the relative density of the YSZmembrane tube reaches 98.1% of theoretical density at sintering temperature of 1600,approaching the theoretical density.The maximum of open voltage is 1.213 V, and the maximum of output power is 0.48 W.The electrical property of the SOFCwith hydrogen as fuel is superior to that of the one with city coal gas as fuel.
    Ordered Assembly of Triblock Copolymer on Air-water Interface
    WANG Gang, WEI Li, HONG Xia, WANG Da-Yang, YANG Wen-Sheng, LIU Feng-Qi, LI Tie-Jin, BAI Yu-Bai
    2002, 23(5):  937-940. 
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    Sulfonated hydrogenated styrene-butadiene-styrene triblock copolymer(S-SEBS) was prepared by reaction of hydrogenated styrene-butadiene-styrene triblock copolymer(SEBS) with acetic anhydride and sulphuric acid.The assembly of S-SEBSon air-water interface was studied by using Langmuir film balance.Langmuir-Blogett(LB) film of S-SEBS was prepared and investigated by atomic force microscopy (AFM) in non-contact mode.The aggregations of S-SEBSin solution and in LBfilms were studied by fluorescence spectroscopy by using pyrene as fluorescence probe.The experimental results show that the ordered 2D and 3D-nanostructures composed of amphiphilic nanospheres have been obtained on the air-water interface.Apossible mechanism for the formation of the nanostructures is proposed.
    Studies on Energy Level Splitting of 9-Hydroxyphenalenone in the Ground State by Using a Solvable Sextic Function
    LIU Hai-Ying, DING Shi-Liang
    2002, 23(5):  941-943. 
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    The double-well potential model is very useful for describing proton transfer.And the curve pic-ture of the sextic function V(R, γ) =R6+2γR4 + (γ2+μ)R2 has a double-well form, when γ and μ satisfya specific conditions.So it can be used as the potential function of proton transfer by modification.Mostimportantly, its corresponding Schrdriinger equation has exact1y analytic solutions.Thus it shows its su-periority over the quartic one V(R) =A(R4-BR2) which has double-well form, but is not a solvable po-tential function.Based on the sextic function, the energy level splitting of the ground state of 9-hydrox-yphenalone was studied by using linear variational method.The obtained results is better compared withthe experimental ones.
    AFM Study of Gold Nano wires Array Electrodeposited Under AC Lower Frequency
    SU Yi-Kun, WANG Zhen, LI Hu-Lin
    2002, 23(5):  944-946. 
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    Hexagonally ordered microporous aluminum anoxic oxide(AAO) template was prepared by two-step anodization process.The thickness and diameter of the anodic alumina pore is proportional to the an-odization voltage and the second time anodization.Au/AAOmembrane was also characterized by X-ray diffraction (XRD).Gold nanowires array was prepared in AAOby a lower frequency ACelectrodeposition.The deposition rate of gold nanoparticles under the lower frequency is slower than under the higher frequency,so the membrane surface of Gold/AAOis uniform.The morphology of the nanowires array uniformly filled in hexagonally ordered pore was also monitored by atomic force microscope (AFM) after dissolution parts of alumina film.
    Preparation and Property of High Surface Area Alumina Resisting High TemperatureEffect of Barium Addition and Its Synergy with Lanthanum on the Thermal Stability of Alumina
    GONG Mao-Chu, ZHANG Jie, LIN Zhi-En, XIE Chun-Ying, CHEN Yao-Qiang, ZHENG Lin, LI Xiao-Wei, XU Qing-Huai
    2002, 23(5):  947-949. 
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    High surface area alumina resisting high temperature was prepared by sol-gel method or sol-gel assisted impregnation method.The effects of barium addition and its synergy with lanthanum on the thermal stability were studied by XRDand surface analysis techniques.The results showed that when Ba was introduced by sol-gel method, Ba showed a little effect in improving the thermal stability of alumina.While 5.2% La introduced by sol-gel method and 2.0% Ba was introduced by impregnation method, because of the synergy between barium and lanthanum, the alumina maintained surface area of 112.90 m2/g after calcination at 1100 for 32 h.
    Studies on the Calculation Method for Molecular Surface Areaof Chemical Compounds
    GUO Ming, LIU Wen-Jie, WANG Yong-Mei
    2002, 23(5):  950-952. 
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    A new algorithm is suggested to calculate the molecular surface area.The statistics method of random variable is introduced to the calculation system for the first time, which can be used to calculate molecular surface area of molecular conformation in any case.The result shows that this algorithm has the same accuracy as the others.Besides, the method possesses the advantage of simplicity and directness and quick-speed.
    Oxidation of Hexanol to Hexanoic Acid over SiO2 Supported Peroxotungsto-phospho-quaternary Ammonium Catalyst System
    BI Ying-Li, WANG Min, ZHUANG Hong, XIAN Mo, LI Wen-Xing, ZHEN Kai-Ji
    2002, 23(5):  953-954. 
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    The factors influencing the catalytic properties for the oxidation of hexanol to hexanoic acid over SiO2 supported peroxotungsto-phospho-quaternary ammonium catalyst were investigated.The catalysts were characterized by means of IRand BETtechniques.The influence of different reaction conditions such as reaction temperature, reaction time, amount of hydrogen peroxide and catalyst was discussed for the oxidation reaction.The optimal reaction conditions were given.SiO2 supported POWPcatalysts are obviously superior to the unsupported POWP under the same reaction condition.
    REMPI Analysis of Air Pollutants Caused by Car Exhaust
    PENG Wei-Xian, LOU Xiao-Jie, XU Huai-Liang, DAI Zhen-Wen
    2002, 23(5):  955-957. 
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    A laser-based ultra-sensitive detection technique used for determining urban air pollutants caused by car exhaust has been described.Asmall ion chamber working under the condition of atmospheric pressure was used as the detector and a laser system with UVoutput was used as the light source.A 1 + 1 and a 2 + 1 REMPI scheme were used for the ultra-sensitive analysis of NOx(x=1 ,2) and COin car exhaust.
    The Channel Behavior of Gramicidin in Mercaptan Self-assembled Monolayer Membrane
    GUO Ji-Dong, XING Wei, LU Tian-Hong, YANG Hui
    2002, 23(5):  958-960. 
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    The present paper reports the channel behavior of gramicidin in mercaptan self-assembled mono-layer on the surface of the gold electrode by using the electrochemical method.The current responses to K+ ions and the electrode potential for the gold electrodes modified .with self-assembled mercaptan mono-layer incorporating and not incorporating gramicidin Dwere compared.The results firstly indicated that gramicidin Dmolecules can be incorporated into the mercaptan monolayer assembled on the surface of the gold electrode and form monovalent ion channel.Amechanism of the phenomenon was proposed.
    Characteristic Dynamic Rheological Response to Phase Separation for Poly(methyl methacrylate)/Poly(styrene-co-acrylonitrile) Blends
    DU Miao, WANG Li-Qun, YANG Bi-Bo, SONG Xu-Bing, ZHENG Qiang
    2002, 23(5):  961-964. 
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    On the basis of phase separation temperatures (Tc) for poly (methyl methacrylate )/poly-(styrene-co-acrylonitrile) (PMMA/SAN) blends with different compositions, measured by small angle laser light scattering (SALLS), we have studied the dynamic rheological behavior of these blends at various temperatures below, near and above Tc.The results showed that the time-temperature superposition principle could be applied and the linear viscoelastic response emerged in the terminal region at temperatures below Tc.However, it was found that the breakdown of time-temperature superposition principle appeared, and viscoelastic response was deviated from the linear behavior in the terminal region at temperatures near and above Tc.
    The Effect of Water Absorption on the Behavior of Dynamic Relaxation of the Epoxy Resins
    DING Yi-Fu, LI Hua, LIU Mo-Jun, WU Xian-Guo, LI Shan-Jun
    2002, 23(5):  965-969. 
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    O-Cresol novolac epoxy resins (ECN) were cured with phenol novolac resin (NOV) and three esterified phenol novolac resins.Gravimetric method and DMAwere used to study the effect of water absorption on the dynamic relaxation.Experimental results show that the relaxation behavior is greatly affected by the water absorption, which is affected by the polarity and the flexibility of the side groups.
    Research on Molecular Dynamic Simulation in Macromolecular System
    SHEN Rong-Xin, FANG Ya-Yin, ZHAO Wei, SUN Hong-Wei, Yuan Man-Xue, LAI Cheng-Ming
    2002, 23(5):  970-973. 
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    Single polyethylene chain has been used as a model for investigating various molecular dynamic simulation methods that could be useful in the study of macromolecule system.The result of the investigation indicated that different force fields caused obviously different structures of polyethylene.When using OPLSforce field under vacuum condition, the phenomena of vitrification were found at 100 K, the phenomena of local crystallization was found at 200 and 300 K, and the phenomena of melting were found at 400 and 500 K.When the periodic box was added to the system, both the disordered state and crystalline state throw out stability to some extent at 300 Kin molecular dynamic simulation.
    Characterization of p-Aminobenzoic-acid-modified Epoxy Resin and Its Emulsification Properties
    ZHANG Zhao-Ying, HUANG Yu-Hui, LIAO Bing, CONG Guang-Min
    2002, 23(5):  974-978. 
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    The bisphenol type epoxy resin was modified by p-aminobenzoic acid to from amphophilic products.Although the modified resins had a poorer solubility in organic solvents, they tended to be dissolved more easily in basic solvents.The modified resins were characterized by using IRspectroscopy and DSC.The IRspectra of the modified resin indicate that the epoxy conversion increased with the increase of the content of p-aminobenzoic acid.The DSCcurves demonstrated the same trend of the glass transition temperature of the modified resins.The conductivity variations during the emulsification process of different systems were investigated.The dissociation of carboxyl groups and aggregation of particles during emulsification were proposed for the conductivity variation.The influence of neutralization value and solvent polarity on the particle size and morphology of the modified resin emulsion were also studied.
    Studies on Superoxide Formation in Photosystem Ⅱ with a Novel Spin Trap
    SUN Jian, LIU Ke, XU Ying-Kai, CHEN Zhong-Wei, LIU Yang
    2002, 23(5):  979-981. 
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    Under strong illumination, photosystem Ⅱ (PS Ⅱ )of higher plant was active in superoxide production.However, it keeps unclear about the mechanisms and sites of superoxide formation by PS Ⅱ .Concerning above questions, the molecular mechanisms of superoxide formation by PS IIfrom spinach in this work has been studied.The site range for possible superoxide formation by PS Ihas been constricted by the study on the donor or acceptor inhibited PS Ipreparation.The results indicated that the plasto-quinones located at QA and QB of PS Ⅱ was the primary site responsible for superoxide formation.
    Studies on Catalyst Containing Novel Asymmetric Diether forPropene Polymerization
    XU De-Min, MA Zhi, MI Xia, KE Yu-Cai, HU You-Liang, WU Chun-Hong
    2002, 23(5):  982-984. 
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    MgCl2 supported Ziegler-Natta catalyst containing a novel asymmetric diether as internal donor was prepared for polymerization of propene.The effects of polymerization temperature and the n(Al)/ n(Ti) ratio on the catalytic activity and the molecular weight, the isotacticity and the melting point of polypropene were investigated.In comparison with the symmetric diether catalysts, the catalytic activity and the isotacticity of polypropene were much lower.The stereosequence distributions were analyzed by means of 13C NMR and the results obtained indicate that isotactic, syndiotactic and iso-syndiotactic block polypropenes were produced.The stereo effect of MBF and the polymerization mechanism were discussed.
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