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Table of Content

    24 May 1997, Volume 18 Issue 5
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    Articles
    Synthesis of C60-Pyrrolidine Derivatives by 1,3-Dipolar Cycloaddition of Azomethine Ylides to C60
    ZHOU De-Jian, ZHAO Yi-Lei, GAN Liang-Bing, LUO Chu-Ping, HUANG Chun-Hui, LU Mu-Jian, PAN Jinn-Qi, WU Yi
    1997, 18(5):  665-670. 
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    Aseries of different substituted azomethine Ylides were prepared through the reaction between sarcosine and different substituted benzoaldehydes, conjugated aldehydes and ketones.Further 1, 3-dipolar cycloaddition of these azomethine Ylides to C60 give rise to a series of new C60-pyrrolidine derivatives.The molecular structures of these compounds were ldent1fied and characterized by 1HNMR, 13CNMR, FDMS, FT-IRand UV-Vis spectro-scopies.
    Electrochemistry Characteristics of Adriamycin-Fe(Ⅲ) Complex and Its Interaction with DNA
    WANG Hong-Fei, YANG Pin, LI Qing-Shan, WU Qiang
    1997, 18(5):  671-675. 
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    Electrochemistry characteristics of adriamycin-Fe(Ⅲ) complex was studied by the methods of osillopolarograph and cyclic voltammetry.At physiological pH, Fe (Ⅲ) binds with ADMto form a complex of 2: 1 stoichiometry.ADMwas reduced at a more negative potential when it was complexed with Fe(Ⅲ), which is close related to the low cardiac toxicity of the complex.The interaction model of ADM-Fe(Ⅲ) complex with DNAwas studied by the methods of spectroscopy, electrochemlstry and electrophoresis.The complex preserves the DNAintercalation characteristics, and binds to DNAto form a ternary complex composed of DNA, Fe(Ⅲ) and ADM.
    Preparation, Crystal Structure and Thermolysis Mechanism of [Y(NTO)2NO3(H2O)5]·2H2O
    SONG Ji-Rong, HU Rong-Zu, LI Fu-Ping, MAO Zhi-Hua, ZHOU Zong-Hua, HONG Zhou
    1997, 18(5):  676-679. 
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    [Y(NTO)2NO3 (H2O)5].2H2Owas prepared by mixing the aqueous solution oflithium 3-nitro-1 2, 4-triazol-5uonate and the dilute nitric acid solution of yttrium oxide.The single crystal structure was determined by a four-circle X-ray diffractometer.The crystal is monoclinic, space group Cm with crystal parameters of a = 0.6773(2) nm, b= 2.0866(2)nm, c=0.6551(1) nm; β=102.98(2)°, V=0.9021(1) nm3, Z=2, Dc=1.970 g.cm-3,p=33.49 cm-1, F(000) =540, R=0.032.The two carbonyls of NTOanion, one NO3-, and five water molecules are coordinated to Y3+.The coordinate bond lengths are between 0.2283 nm and 0.2478 nm, so the distorted dodecahedron is formed.Based on the thermal analysis, the thermolysis mechanism of [Y(NTO)2NO3(H2O)5].2H2Ohas been derived.
    Synthesis of Magnesium Nitride of Nanometric Size
    ZHANG Yuan-Kui, LIAO Shi-Jian, Xu Yun
    1997, 18(5):  680-681. 
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    Magnesium nitride powder of nanometric size was prepared by reaction of magne sium in highly reactive form (Mg*) with nitrogen gas under mild conditions in high yields.This Mg* was obtained by the thermal decomposit on of magnesium anthracene.3THFat 200℃ under vacuum.The average particle size of Mg3N2 obtained is around 20-3Onm as shown by the transmission electron microscopy.At 450 ℃ at normal pressure of N, atom sphere, the yield of Mg3N2 by the nitridation of Mg doped with NiCl2 is 93% in 20 h.
    Synthesis of Long Aliphatic Carbochain Porphyrins and Their LB Films and Study on Their Gas Sensitivity
    LIU Yu-Wen, ZHAO Yu-E, WANG Li-Bo, WANG Run-Wei, LIANG Hong-Bin, ZHU Hao, CAO Xi-Zhang
    1997, 18(5):  682-684. 
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    Tetranicotinamidephenyl porphyrin(TNAPP) reacts with n-C16H33Br and n-C12H25 Br, respectively to yield the products tetra (N-hexadecyl nicotinamide phenyl) porphyrin bromide (THNAPPBr) and tetra-(N-dodecylnicotinamide phenyl) porphyrin bromide.Its cobalt complex and zinc complex are also prepared.Those porphyrins and metal porphyrins have good film-forming properties.The gas sensitivity studies show that the six kinds of porphyrins are sensitive to NH3 and has a fine selectivity.
    Investigation of the Stability of Microemulsion in Extraction Organic Phase of Saponated P507
    SHEN Xing-Hai, LI Gai-Ling, GAO Hong-Cheng
    1997, 18(5):  685-687. 
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    The activation energy ΔEcan indicate the strength of the interfacial membranes of microemulsion particles, so it could be used to discribe and discuss the stability of the formed microemulsion in extraction organic phase-Variations of activation energies with water content for microemulsions formed in the organic phase of saponated P507 (2-ethyl-hexylphosphonic acid mono-2-ethylhexyl ester)-alcohol (n-propanol, n-butanol, n-pentanol and n-hexanol)-heptane-water were determined by measurement of electric conductivity.The curves between ΔEand water content VH2O were given.It is found that ΔEof butanol system decreases slightly with the increase of water content, while that of pentanol and hexanol systems presents a maximum.It is also found that the activati0n energy increases with the increase of the length of alcohol chain.These results reveal that the longer the length of alcohol chain, the bigger the strength of the interfacial membranes of particles, and the more stable the microemulsion is.Based on the above results, hexanol or octanol was always used as co-surfactant in extraction process.
    Studies on the Transmembrane of Rare Earth Coordination Compound by Phosphorescent Probe Method
    MA Gui-Bin, GUO Yu-Ling, CHEN Liang, ZHAO Jian-Guo, YANG Pin, ZHAO Chun-Gui
    1997, 18(5):  688-690. 
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    Varied behavior of luminophors phosphorescent life of rare earth terbium coordination compound as a molecular probe existing in different concentration quench of dioxygen and lipoid system was studied by phosphorescent spectrum.The terblum coordination compound probe was applied to study the interaction between rare earth and cells.The research results show that the molecular probe of terbium coordination compound was an effective probe for applying to the study of transmembrane process for rare earth ions.
    Studies on the Mechanism of Fluorescence Quenching of Tb3+-Tiron Complex by Nucleotides, Polynucleotides and Nucleic Acids
    ZHAO Yi-Bing, WANG Dong-Yuan, GUO Xiang-Qun, XU Jin-Gou
    1997, 18(5):  691-695. 
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    The mechanism of fluorescence quenching of Tb3+-Trion complex by nucleotides,polynucleotides and nucleic acids has been studied.It was considered that it is a static quenching which is based on the phosphate moieties of nucleotides, polynucleotides and nucleic acids conpeting the Tb3+ ion with Tiron and forming non-fluorescent binary complex under the optimal conditions.The experimental results of nucleic acids reacting with intercalating reagent of DNAor metal ion using Tb3+-Trion complex as a fluorescence probe indicated that the mechanism is reasonable.
    Detection of Combustible Material with Piezoelectric Crystal Sensor Array Using Pattern-Recognition Techniques
    XING Wan-Li, FANG Yan-Hong, HE Xi-Wen
    1997, 18(5):  696-700. 
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    Agas sensors array with seven piezoelectric crystals each coated with a different partially selective coating material was constructed to identify four kinds of combustible material which generate smoke contammg different components.The signals from the sensors were analyzed with both conventional multivariate analysis, stepwise discriminant analysis (SDA), and artificial neural networks (ANN).The results show that the predictions were even better with ANNmodels.In our experiment, we have reported a new method for training data selection," stepwise expanding training set method" to solve the problem that the network can not converge at the beginning of training.
    Studies on Protein Denaturation by Sizc-exclusion Chromatography
    CHEN Guo-Liang, LI Rong, LI Hua-Ru
    1997, 18(5):  701-705. 
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    Asize-excltlsion chromatography able to study conformational change during protein denaturation was proposed by comparing the correlations between protein biophysicalproperties and chromatographic behaviors.The relatiove volume of denatured protein may becompared by e-exclusion chromatography in term o fchanges in retention time.The numberof forming denatured species can be determined by chromatographic peak number.The expansion extent of protein may be described using changes in peak shape and peak number.The exposure of aromatic amino acid residues in denatured proteins can also be deduced from peak height under different wave lengths.We utilized the extablished size-exclusion chromatography to examine the denatured aspects for liquid and solid a-amylase upon long term storage under lower temperature, to discuss the influence of denaturation time and denaturation temperature on unfolding behavior of proteins
    The Electrochemical Characteristics of Gold Electrode Modified by Thionine Covalently Bound to Self-assembled Cysteamine Monolayer and Its Electrocatalytic Oxidation for Ascorbic Acid
    XU Jing-Juan, FANG Hui-Qun, CHEN Hong-Yuan
    1997, 18(5):  706-710. 
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    Agold electrode modified by thionine covalently bound to self-assembled cysteamine monolayer (Th-SAM) has been prepared.The electrochemical properties of this ThSAMmodified electrode was investigated by electrochemical methods.There were two redox couples when it was swept in the range of -0.45-+0.50 V(vs.SCE) by cyclic voltammetry.As to pH7.7, the peak potentials were Epa1＝214mV。Epc1＝82mV,Epa2＝－75mV,Epc2＝－160mV, respectively.The participating number of proton was 2 for peak 1 and 1 for peak 2 in the pHrange between 5.0 and 9.0.The surface electron transfer rate constant(ks)of peak 2 was 0.02 s-1.The Th-SAMmodified electrode could be successfully used for the electrocatalytic oxidation of ascorbic acid and the catalytic currents increased linearly with the ascorbic acid concentration in the range of 1.0 ×10-6-4.0×10-3 mol/L-The heteroge neous electron transfer rate constant was about 2.68×10-3 cm/s.
    A Study on the Properties and H+ Ion Sensitive Function of Poly(n-butylamine) Film Polymerized by Plasma
    XIANG Jian-Nan, ZHANG Wei-Qiang, WANG Ke-Min, YAN Yong-Hong, WANG Bin-Feng, YIN Xia
    1997, 18(5):  711-715. 
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    Thin organic polymer films with properties of good chemicaIstability and good adhesion to glass and vitreous carbon and some metal substrates were prepared by plasma poly merization using n-butylamine as a monomer.Studies on IRspectrum and elemental analysis and other chemical properties showed that these polymer films had a very highly branched and cross-linked structure with good resistance to heat and erosion.The potential metric chemical sensors constructed by this kind of sensitive membranes of plasma poly (n-buty-lamine) gave a super-Nernst response to H+ ion in strong acid solution, and these electrodes had good stability and reproducibility.
    Quantitative Analysis of Gray System for the Spectra of Background and Analytes Severely Overlapped by Using pH Distribution-spectra
    C0NG Pei-Sheng, ZHU Zhong-Liang, LI Tong-Hua
    1997, 18(5):  716-719. 
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    The differences among components were increased because each component appears to be several species in an acid-base mixture.Based on the thesis of RBL, it has been achieved to use this information and introduce pHdistribution-spectra information into quantitative analysis of gray system by combining numeric genetic algorithm.The result shows that for gray systems which the spectra of background and analytes severely overlaps the prediction accuracy for analytes is higher.
    Investigation on the Separation of Maltooligosaccharide by Capillary Zone Electrophoresis
    XU Dan-Ke, CHEN Hong-Yuan, ZHU Shu-Tao
    1997, 18(5):  720-722. 
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    The effect of ionic hydrodynamic radius in the separation of capillary zone electrophoresis is discussed by using maltooligosaccharide as model compounds.The linear correlation between μep and n-1 (n is the number containing the glycosyl units) has been derived and has experimentally been verified with various buffer systems and separation voltages.The results show that hydrodynamic radius is one of the actual factors in HPCZEother than molecular weights.The proposed equation could provide the approach determining glycosyl units of maltooligosaccharide.
    Studies on the Properties and Mechanism for Organobentonites to Adsorb Organic Compounds
    LI Yi-Min, ZHU Li-Zhong, WANG Ju, ZHANG Jian-Ying
    1997, 18(5):  723-725. 
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    Three organobentonites were synthesized by placing cation surfactants such as octadecyltrimethylammonium bromide (OTMAD), cetyltrimethylammonium bromide (CTMAB) and dodecyltrimethylammonium bromide(DTMAB) on bentonite.The properties for organobentonites to adsorb phenol, p-nitrophenol, aniline, nitrobenzene and 1-naphthylamine in water were investigated in detail.The mechanism that organic compounds were adsorbed by organobentonites was studied.The removal rates for organobentonites to treat organic compounds from water were associated with the properties of organic compounds, the ammount of cation surfactants exchanged on the bentonite and the length of alkyl chain of the cation surfactant.
    Quantitative Structure-Activity Relationship Study of HerbicidaI 1,4,2-Diazaphospholidin-5(thi)one-2-oxides
    CHEN Ru-Yu, HE Liang-Nian, YANG Hua-Zheng, YANG Xiu-Feng, WANG Hui-Lin
    1997, 18(5):  726-729. 
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    The quantitative relationship between the structure of 1,4,2-diazaphospholidin-5(thi)one-2-oxides and their herbicidal activity on the rape was analyzed, using the physicochemical parameters of the substitutents and regression analysis.The results were used in guiding the synthesis of higher active compounds and verification.
    Studies on Potassium Channel Openers(Ⅰ)─Synthesis and Cardiovascular Activity of Substituted trans-4-Amino-3, 4-dihydro-2, 2-dimethyl-2H-1-benzopyran-3-ols
    SUN Hong-Bin, HUA Wei-Yi, CHEN Ling, PENG Si-Xun, WANG Ting, LIU Guo-Qing
    1997, 18(5):  730-733. 
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    Thirteen novel substituted trans-4-amino-3, 4-dihydro-2, 2-dimethyl-2H-1-ben zopyran-3-ols have been prepared and evaluated for their relaxant activity in the anaesthetized normotensive sprague-dawley rats.The synthetic route to these compounds involves the conversion of 2H-1-benzopyrans to bromohydrins, followed by conversion to epoxides,which were ring opened with appropriate amines or acylhydrazines.Some of these compounds showed marked vasodilator and antihypertensive activities.
    Synthesis of the IS3 Segment of the Rat Brain Sodium Ion Channel
    MIAO Zhen-Wei, JIANG Yun, LI Xiang-Qun, XU Xiao-Jie, TANG You-Qi
    1997, 18(5):  734-738. 
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    The IS3 segment, a peptide with 22 amino acid residues in length, of the rat brain sodium ion channel was synthesized by the fragment condensation using the phenacylester as the temporary protection group of a-carboxyl group.After removal of the protection group,the crude product was purified by HPLCfirst on Protein Parck column and then on C18 column, using 40% acetonitrile in 0.1 mol/L NH4HCO3 aqueous solution as the mobile phase.The purified IS3 segment was confirmed by amino acid analysis and FAB-MS.
    Synthesis and Biological Activity of Silicon-containing Phosphorodithioates
    HE Zheng-Jie, LI Zheng-Ming, BI Fu-Chun, WANG Wen-Li
    1997, 18(5):  739-743. 
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    Silylmethanethiols R1R2MeSiCH2SHsmoothly undergo Mannich-type condensation reaction with O,O-dialkyl phosphorodithioates (RO)2P(S)SHand formaldehyde.By utilizing the above reaction and nucleophilic substitution of O,O-diethyl-S-(2-bromoethyl)phos phorodithioate with silylmethanethiols, 37 novel si1icon-containing phosphorodithioates (RO)2P (S)S (CH2)nSCH2SiMe R1R2 (n = 1, 2) were synthesized.The bioassay results show that the main title compounds possess some insecticidal and acaricidal activities at the preliminary screening concentration.
    Chemical Modification of Tryptophan Residues in Human Plasminogen
    ZHAO Chen-Guang, LIU Lan-Ying, QIU Ai-Dong, LIU Shu-Ying
    1997, 18(5):  744-747. 
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    Tryptophan(Trp) residues in human plasminogen(HPg) was modified by N-bro-mossuccinimide(NBS).The results indicate that there are 19 tryptophan residues in HPg.Five tryptophan residues are located on the surface of the enzymogen, two of them are fast reactive residues.Among all the Trp residues, one is essential for the activity of the enzyme and may be located at the substrate binding site of the enzyme.The spectra of circular dichroism(CD) of HPg are changed after treatment with NBS.
    The Structure of a New Sesquiterpene from Ligularia Dentata
    GAO Kun, YANG Li, JIA Zhong-Jian
    1997, 18(5):  748-749. 
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    Anew germacrane sesquiterpene was obtained from the roots of L.Dentata which was a folk herb medicine in China-Its structure was elucidated to be 1α, 4β, 6α, 10a-tetrahy-droxy-3β, 5a, 8a-triangeloyloxygermacr-11-en-9-one with the spectroscopic techniques (such as IR, MS, 1HNMR, 13CNMRand 2D-NMR) and chemical transformation.
    Syntheses, Structure and SAR Study on Sulfonylurea Compounds(Ⅴ)─Crystal and Molecular Structure of N-[2-(4-Ethyl)triazinyl]-2-nitrobenzene Sulfonylurea
    LI Zheng-Ming, LIU Jie, WANG Xia, YUAN Man-Xue, LAI Cheng-Ming
    1997, 18(5):  750-752. 
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    Synthesis and crystal structure of the title molecule was reported here.The crystal is monoclinic, belonging to space group P21/n, with unit cell parameters a = 0.7861 (3)nm, b=0.5809(2) nm, c=3.2729(6) nm, β=93.25°, V=1.492(1) nm3, Dx=1.568 g/cm3, μ=2.441 cm-1, F(00 0) =728 for 1084 reflections.R=0.046, Rw=0.046.Molecular structure was discussed.There are three different planes in the molecule, with a conjugated system in each.The conformation difference between this molecule and other sulfonylure a molecule which has a different bioactivity was compared.
    Studies on the Metabolism of Mitochondria and Sub-mitochondria and the Effect of Laccase on It by Microcalorimetry
    XIONG Ya, TAN Zhi-Qun, LIU Yi, PAN Zheng-Jun, WU Ding-Quan, KANG Li-Shan, QU Song-Sheng
    1997, 18(5):  753-756. 
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    Microcalorimetry was first applied to investigating sub-cell organ.The metabolism of mitochondria and sub-mitochondria, and the effect of laccase on sub-mito-chondria were studied by microcalorimetry.Their metabolism thermokinetic parameters were obtained by the MTDequation and evolutionary optimization.It is found that the metabolism rate constant and the heat of mitochondria are almost the same as that of sub-mitochondria, and laccase may enormously speed the metabolism of mitochondria although the metabolism heat of sub-mitochondria-laccase system is almost the same as sub-mitochondria.
    Magnetic Design of Trinitrene
    LU Hui-Zhe, FU Qiang, QIU Yong-Qing, ZHAO Cheng-Da
    1997, 18(5):  757-759. 
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    The molecular structures and magnetism of a series of trinitrenes were designed by ab initio UHFmethod and their magnetism was discussed on the basis of considering the effects of geometries and substituents.The results indicate that these molecules are all ferromagnetic and have high spin states.The values of Jab change with different substituents.One of these values we proposed is expected to be synthesized because of its high Jab value and low total energy.
    Studies on the Preparation of AOT-n-Heptane Microemulsion and Transport of Metal Ions Through the Microemulsion System
    HAN Li-Xin, LI Ke-An, TONG Shen-Yang
    1997, 18(5):  760-763. 
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    The water-in-oil(W/0) microemulsions have been prepared by using the surfactant diethylhexyl sodium sulphasuccinate and the oil solvent n-heptane.The transporting behavior of metal ions, such as Cu2+, Zn2+, Pb2+, Cd2+, Hg2+, Co2+, Ni2+, Cr3+ and Cr(VI),has been studied from the water phases or feed phases into the microemulsion phases.The optimum conditions of preparing microemulsions and transporting metal ions have been obtained.The experimental results show that all of these metal ions studied except Cr(VI)have high transport ratios under these conditions.
    Crystal Field Splitting of Nd3+ Ion and Chemical Bonds on the Host Crystals
    WU Cheng-Xun, ZHANG Si-Yuan, DING Pei-Zhu
    1997, 18(5):  764-766. 
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    In terms of the theory of chemical bonds on complex crystals(CBCC), the crystal structure and coordination, the chemical bond parameters of a group of ABO4-type crystalswere calculated in detail.The results show that the relation between the crystal field splitting of Nd3+ ion and the covalency of the crystal is linear.
    Studies on Changing Regulations of the Electronic Polarizability and the Stability of Polyacence Homologue
    HUO Yu-Qiu, SU Zhong-Min, HUANG Zong-Hao, WANG Xiu-Jun, WANG Rong-Shun
    1997, 18(5):  767-771. 
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    The quantum chemistry CNDO/2 method introduced with external electric field perturbation is used to calculate the energies and the electronic polarizability of polyacene homologue (C4n+2,H2n+4).The results indicate that the polarizabilities of total and л electrons in crease with the increasing of the ring numbers, but the increasing rate reduces gradually.When n is large enough, the increasing rate tends to be a constant.The increasing rate of polarizability along the direction of molecular chain is much larger than that along other directions.The increasing rate of л electronic polarizability is generally higher than that of the total one.The stability laws of polyacene homologue are: the stability of the trans-type is about the same as that of the cis-type.Both of them are more stable that the average-bond type.The energies of all systems.decrease when the length of molecular chains are gradually increased.The decreasing values reduce a little with the increasing of the length of molecular chains.
    Studies on Mixed-Valence Compounds(Ⅱ)─Electrochemical and in situ UV-Vis-Near-IR and FTIR Spectroelectrochemical Studies of Mixed-Valence Heteropolyanion [HAs2Mo18O62]n- in Aprotic Media
    ZHANG Shu-Yan, SUN Hao-Ran, YANG Guo-Yu, XU Ji-Qing
    1997, 18(5):  772-776. 
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    The mixed-valence heteropolyanion [HAs2Mo18O62]n- (n= 6, 7, 8, 9) were inves tigated by electrochemical and in-situ UV-Vis-Near-IRand FTIRspectroelectrochemical methods in aprotic media.The results indicate that the heteropolyanion [HAs2Mo18O62]5- with four step one electron transfer reductions and the mixed-valence heteropolyanions [HAs2Mo18O62]n- (n = 6, 7, 8, 9) were formed after electroreduction.The mixed-valence heteropolyanions have IVCTbands in Near-IRspectral region-The characteristic absorption of Mo = Odouble bond and the Mo-Obridge bond shift to low wavenumber after electrore duction.
    In situ Infrared Studies of the Catalytical Synthesis of Dimethyl Oxalate from CO and CH3ONO Over Al2O3 Supported Pd-Cu Alloy Catalysts
    LIANG Xian-Zhen, ZHAO Wei-Jun, YANG Rui-Hua, FENG Ming-Hua, WANG Zhong-Wen, MA Xin-Bin, XU Gen-Hui
    1997, 18(5):  777-781. 
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    The catalytical synthesis of dimethyl oxalate from COand CH3ONOat normal pressure was investigated with in situ IRtechnique.We discovered that there was a subsidiary reaction during the formation of dimethyl oxaIate.The by-product NOcontinued to react with COto produce CO2 and N2O.Palladium was dispersed by copper in the alloy Pd Cu catalysts and consequently results in the increase of the linearly bound COspecies and the decrease of the multiply coordinated COspecies.The main reaction has no relation with the multiply coordinated COspecies but the subsidiary reaction firmly depends on them.The linearly bound COof 2058 cm-1 are more active in the production of dimethyl oxalate.The possible mechanism was also discussed.
    Ab Initio Calculations on HCnS- and HSCn- Cluster Ions
    LIU Zhao-Yang, HUANG Rong-Bin, ZHENG Lan-Sun
    1997, 18(5):  782-785. 
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    Ab initio calculations were carried on the cluster anions composed of 1-9 carbon atoms, a sulfur atom and a hydrogen atom.Two structural isomers, HCnS- and HSCn-,were considered and HF/6-31Gbasis set was selected for the calculation of the optimum molecular geometry, total electron energy and fragmentation energy of various dissociation paths.The calculated results show that, among the two structural isomers, HCnS- is more stable than HSCn-, and the cluster anions with even n are more stable than those with odd n.The calculation result is consistent with the experimental observations.
    Studies on the Reaction Between Laccase and 3,4,5-Trihydroxybenzoic Acid by Microcalorimetry
    WANG Tian-Zhi, WU Ding-Quan, WAN Hong-Went, QU Song-Sheng, DU Yu-Min
    1997, 18(5):  786-790. 
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    The reactions between laccase and 3,4,5-trihydroxybenzoic acid have been studied by LKB-2107 batch microcalorimetry system at different temperatures and pH = 7.4.The rnolar reaction enthalpy (ΔrHm), the Michaelis constant (Km), the rate constant (k2), the laccase activity (EA), the binding energy (ΔG0), the activation Gibbs free energy (ΔG≠T),the actlvation energy(Ea) and the activation entropy (ΔS≠T) have been determined.The results have been discussed from changes in free energy by using the transition state theory.The activation entropy (ΔS≠T ＜ 0) indicated that enzyme-substrate/transition structure is　bound more orderly than enzyme-substrate complex.
    Atomic Force Microscopic Observation of Local Supramolecular Structure in Phosphatidic Acid Langmuir-Blodgett Films
    YUAN Chun-Bo, DING De-Sheng, GU Ning, LU Zu-Hong, LIU Ju-Zheng
    1997, 18(5):  791-794. 
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    The Langmuir-Blodgett bilayer films of phosphatidic acid(DPPA) have been in vestigated by using atomic force microscopy in both large and nano-scale.Large scale AFMimage shows that the bilayer of DPPAis a plane film with some defects which enable us to detect the thickness of bilayer by a trace of section analysis across the defects structure.Molecularly resolved images show that the polar head groups (phosphate groups) are packed in an ordered hexagonal organization with a long range orientational and positional ordering.Intermolecular hydrogen bonding interactions between adjacent phosphate groups are first visualized and local supramolecular structures are first observed in polar region of DPPAbilayer.Some phosphate groups in polar region linked with each other through intermolecular hydrogen bonding interaction to form local supramolecular structure with a diameter of 1.5 nm in size.
    Fragmentations of Some Bifunctional Phenylether Compounds by Intermediate Ion/Neutral Complexes
    SHE Yi-Min, LIU Shu-Ying, YANG Ming-Sheng
    1997, 18(5):  795-799. 
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    The fragmentations of three bifunctional phenylether compounds including 2-(2,6-dichlolo)phenoxyl propionitrile, N-hydroxyl-4-butoxyl phenylacetyl amine (bufexamc) and 2-(1-methylethoxyl) phenol methylcarbamate (Propoxur) under electron impact ionization were reported.Metastable ion(MI) and collision-induced dissociation(CID) at a low energyhave been used to study the fragmentation pathways from molecular ions.Apart from the simple bond cleavages, and the unimolecular dissociations viaion/neutral complex intermediate as a competitive mechanism were demonstrated-Moreover, the intramolecular hydrogen transfer and double hydrogen transfers in the fragmentations of these compounds were discussed in detail.
    Investigation on the Conductivity and Microstructure of Mixed Reverse Micelles
    LIU Dao-Jun, MA Ji-Ming, CHENG Hu-Min, ZHAO Zhen-Guo
    1997, 18(5):  800-802. 
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    Properties and microstructure of mixed reverse micelles of anionic surfactant AOTand nonionic surfactants in n-heptane were investigated using conductivity, fluorescence probe,and dynamic light scattering.As in the reverse micelle formed with AOTalone, a conductivity maximum was also observed in conductivity-W0,(molar ratio of water to surfactants) curves for mixed reverse micellar systems, and W0,mex (W0, at the conductivity maximum) moves to a smaller value with the increase of nonionic surfactants contents and their EOchain length.This phenomenon was interpreted in terms of the results of dynamic light scattering and the microstructure of the mixed reverse micelles.The fluorescent behaviour of fluorescence probe Ru(bPy)32+ in mixed reverse micelles indicates that W0, at which the hydration of head groups of surfactants finished, decreases with the increase of nonionic surfactants contents, but increases with their EOchain length at a constant ratio of nonionic surfactants to AOT.
    Poly(methyl methacrylate)/TiO2 Hybrid Polymer Materials Prepared by the Sol-Gel Process
    HUANG Zhi-Hua, QIU Kun-Yuan
    1997, 18(5):  803-806. 
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    In this paper, the PMMA/TiO2 hybrid polymeric materials were prepared by the sol-gel process.In order to introduce the chemical bond between the organic polymer chain and inorganic network in the hybrid, the trimethoxysilyl functional group was introduced on the polymer side chain by copolymerization with 3-(trimethoxysilyl) propyl methacrylate (MSMA).The result of solvent extraction shows that the gel content in the hybrids with the presence of chemical bond through the reaction of MSMAwith titanium(IV) butoxide is much higher.The chemical structure of the hybrid was analyzed by the FTIR, and the effect of inorganic content on the properties of materials were investigated by TGAand DSC.
    Studies on the Influence of Soft-segment Structure on the Properties of Polyurethane Adhesive
    ZHU Yong-Qun, HUANG Yi-Jun, HU Qiao-Ling, FU Yan-Bin, YU Xiao-Wei
    1997, 18(5):  807-812. 
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    Two series of polyesters were synthesized from adipic acid(AA), dimethyl terephthalate (DMT), isophthalic acid (IPA), phthalic anhydride (PA), with ethylene glycol (EG),butylenediol-1, 4 (1, 4-BDO), propanediol-1, 2 (1, 2-PDO), hexanediol-1, 6 (1, 6-HDO) and diethylene glycol(DEG) respectively by using melt-polycondensation method in the presence of H,PO4, SnCl2.2H2O, (这里有图片,19970536-807-1.gif), as catalyst respectively.The technological conditions of the polyesters synthesized were studied.This polyesters react separately with diphenylmethane diisocyanat (MDI) by solution polymerization to afford two series of linear block polyurethane adhesives.The crystallinity and the melting point of the polyesters and polyurethanes were determined by means of X-ray diffraction (WAXD), differential scanning calorimetry (DSC)-The relationship between structure and properties of the Polyesters, expecially the influence of the polyesters type on adhesion behavior of the corresponding tl1e polyurethanes were discussed.
    Studies on the Syntheses and Properties of Phosphorus containing Polyanhydrides for DDS
    FU Jie, ZHUO Ren-Xi, FAN Chang-Lie
    1997, 18(5):  813-817. 
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    Phosphorus-containing polyanhydrides (2a, 2b) and copolyanhydrides (la-CPP,1b-CPP) were synthesized by melt polycondensation using monomers bis (p-carboxypheny-loxyethyl), ethyl phosphate and bis (p-carboxyphenyloxyethyl), phenyl phosphate.Their chemical structures were confirmed by 1HNMR, FTIR, UVand elementary analysis.The average molecular weight and store stability as well as thermostability of these polyanhydries and copolyanhydrides were investigated.The degradation of polyanhydrides in vitro in phosphate buffer solution at 37℃ was monitored by HPLC.The experimental data revealed that fission of phosphate bond took place after that of the anhydride bond.Enzymatic degradation showed that ribonuclease and alkaline phosphatase can catalyze and accelerate the degradation of these phosphorus-cotaning polyanhydrides.Drug release profile of ciprofloxacin was also studied.
    Studies on Viscosity Enhancement of P(AM-AA)/P(AM-DMDAAC) Complex Used as Polymer Flooding Agent
    DAN Yi, WANG Qi
    1997, 18(5):  818-822. 
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    The viscosity enhancement, resistance to temperature and salt, as well as the oil recovery rate of poly (acrylamide-acrylic acid)/poly (acrylamide-dimethyldiallylammoniumchloride) [P (AM-AA)/P (AM-DMDAAC)] intermacromolecular complex used for polymer flooding agent were studied by means of viscosity measurement and simulated enhanced oil recovery test.The experimental results show that when AAmolar content in P(AM-AA) is 27-02%, DMDAACmolar content in P(AM-DMDAAC) is 4-59%, and the weight ratio of P (AM-AA) to P (AM-DMDAAC) is 5O/50, the viscosity of complexed solution gets its maxium, 3.5 times high as that of P (AM-AA) solution.Compared to the constituents,P(AM-AA)/P(AM-DMDAAC) complex solution exhibits better tolerance to temperature and salt.The result of simulated enhanced oil recovery test shows that, using P(AM-AA)/P(AM-DMDAAC) complex as polymer flooding agent, the oil recovery rate could reach 61-91 %, being 11.91 % higher than the rate of 50% reached by water flooding.
    The Formation and Characterization of Lyotropic Liquid Crystal Phase of Polyaniline Doped with Dodecylbenzene Sulfonic Acid
    ZHENG Yu-Dong, LI Ji-Bo, HUANG Jiong-Liang
    1997, 18(5):  823-825. 
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    Polyaniline thermal doped with dodecylbenzene sulfonic acid was found to form a liquid-crystalline solution in m-cresol.Apolarizing optical microscope and X-ray diffraction measurement were used to study the texture of liquid-crystalline phase.The doped methods had a great effect on the solubility of PAN-DBSAin organic solvents and the appearance of lyotropic liquid crystal of PAN-DBSAsolution.An ordered smectic structure with a layer spacing of d=3.309 nm can be observed for the thermal doped PAN-DBSAin m-cresol.
    Studies on Poly(ether ether ketone ketone)-Poly(ether biphenyl ether ketone ketone) Copolymers and Blends
    NA Hui, YUAN Jing, NI Yu-Wei, ZHANG Wan-Jin, WU Zhong-Wen, ZHANG Hong-Fang, MO Zhi-Shen
    1997, 18(5):  826-828. 
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    We synthesized a series of polymers: poly(ether ether ketone ketone) (PEEKK),poly (ether biphenyl ether ketone ketone) (PEBEKK) and their copolymer by polycondensation.We also prepared a series of PEEKK-PEBEKKblends.By using DSCmethod, we found that Tg of the copolymers and the blends rose with the increasing of biphenyl contents in the polymers.Tc of the copolymers and the blends is higher than the corresponding homopolymer.From the results, we think that PEEKK-PEBEKKcopolymer and blends are miscible and the copolymer is random.
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