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    24 May 1997, Volume 18 Issue 4
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    Articles
    A Study of Top Layer of TiO2 Membrane Prepared by Chemical Vapor Deposition Method
    PENG Ding-Kun, YANG Ping-Hua, LIU Zi-Tao, MENG Guang-Yao
    1997, 18(4):  499-503. 
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    This paper reports the growth of TiO2 thin films deposited on porous α-Al2O3ce-ramic substrates by thermal chemical vapor deposition(CVD) and plasma enhanced CVDpro-cesses using TiCl4 or Ti (OC4H9)4 as the source material.The growth manner and rate of TiO2 films as well as the structure and the surface morphology of the films are observed byXRDand SEM.And their growth mechanism is discussed.We also evaluated the gas perme-ability of the ceramic membranes modified with TiO2, top layer by CVDrnethods.
    Synthesis and Characterization of Zeolite Ti-Fe-ZSM-5 Containing Double Heteroatom
    MA Shu-Jie, LI Lian-Sheng, SUN Fu-Ping, QIU Shi-Lun
    1997, 18(4):  504-508. 
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    The synthesis of zeolite Ti-Fe-ZSM-5 containing double heteroatom with silica solas Si sources, titanium sulfate and iron trichloride as the starting malerials and teterapropy-lammomium bromide, 1, 6-dihexamine and n-butylamine as the templates, respectively in theabsence of alkali metal ions was investigated in detail-Some physico-chemical properties and the structure of the product were characterized by using techniques of XRD, IR, SEM,Mossbauer, UV-Vis, ESRand TG-DTA.It is pr0ved that the double active centers exist inthe product, having a synergistic catalytic oxidative property by the method of GCanalysis ina reaction of phenol hydroxylation.
    Synthesis and Photoelectric Property for (η2-C70)Pd (PPh3)2 Complex
    LIN Yong-Sheng, ZHUANG Yan, WU Zhen-Yi, CHENG Da-Dian, CHEN Zai-Hong, ZHAN Meng-Xiong, ZHENG Lan-Sun
    1997, 18(4):  509-512. 
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    (η2-C70) Pd (PPh3)2 complex was prepared by replacement reactlon in inert gas.The photovoltaic effect (PVE) for (η2-C70) Pd (PPh3)2 complex on GaAs electrode formingn+n heterojunction in photoelectrochemical cell was investigated.The results show thatI2/I3 was the best redox couple in the photoelectrochemical cell.The photovoltaic propertyof (η2-C70)Pd (PPh3)2-GaAs electrode at 1 μm for thickness of (η2-C70)Pd (PPh3)2 was thebest.The photoelectric property of (η2-C70)Pd(PPh3)2 on GaAs electrode was excellent.
    Carboxyester Hydrolysis Promoted by New Zinc(Ⅱ) Macrocyclic Tetraamine Complexes with a Phenol Pendant
    LIN Hua-Kuan, KOU Fu-Ping, ZHU Shou-Rong, CHEN Rong-Ti
    1997, 18(4):  513-518. 
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    Three new macrocyclic tetraamine ligands(L1,L2,L3) bearing substituted phenolpendant were synthesized and charaterized by elementary analysis, IR, and 1H NMR.By pHtitration at 25±0.1℃, I=0.1 mol/L KNO3, studies of protonation of L3 and complexationof Zn(Ⅱ) with L3 have been carried out and revealed that the pendant phenol deprotonateswith relative low PKa values of 8.3 and 8.5 for these two cases, respectively.It is due to theformation of hydrogen bond between phenol and proton combining on the nitrogen atoms ofmacrocycle, and the coordination between phenol and Zn(Ⅱ) metal ion.The Zn(Ⅱ)-boundphenol is shown to be a reactive nucleophile and catalyzes 4-nitrophenyl acetate(NA) hydrol-ysis.Akinetic study of NAhydrolysis by these three ligands'Zn (Ⅱ) complexes in 10%(volume ratio) CH3CNat 25℃, I =0.1 mol/L NaClO4, and pH 8.63 (20mmol/L Trisbuffer), has established a second-order rate constant kc/L (mol/L)-1· s-1 ]of 3.48×10-2,1.52×10-2, 2.85×10-2, respectively.
    Effect of Synthesis Temperature on Structural Transformation of Mesoporous Molecular Sieve M41S Materials──Characterization of Different Structural Materials
    CHEN Xiao-Yin, DING Guo-Zhong, CHEN Hai-Ying, LI Quan-Zhi
    1997, 18(4):  519-524. 
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    For the synthesis system containing cetyltrimethylammonium bromide and sodiumsilicate at low surfactant concentrations and low Sur/Si ratio, the pore and local unit structures of mesoporous M4lSand microporous zeolite ZSM-5, which are obtained in the samesystem at different synthesis temperatures, have been characterized by means 0f N, adsorption-desorption measurments, FTIR, 29Si and 27Al MAS NMRand DTG-The experimentalresults indicate that when synthesis temperature increases from 100℃ to 135℃, the sizes ofmaterials are governed by small crystallites, the pore wall thickness increases but the mesoporous surface areas as well as the volume of materials decrease.When synthesis temperature increases from 135℃ to 150℃, the layers of lamellar M4lSmaterial, obtained fromhexagonal MCM-41 collapse and mesoporous structure disappears due to the removal of thesurfactants by calcination, which are in agreement with experimental findings of XRD.Meanwhile, the double ring vibration band near 598 cm-1 appears in the FTIRspectra.Thesilanols between layers are condensed, resulting in the loss of fine structure in29Si MASNMRspectra.When further increasing synthesis temperature to 165℃, the silanols of framework are highly condensed, resulting in the decrease of Q3/Q4 ratlo greatly.The intensity of double ring vibration band increases and its vibration position shifts to 548 cm-1.Thus, the lamellar M4lSis transformed to zeolite ZSM-5.The DTGresults suggest that theformations of different materials result from the different interactions between surfactantsand silicate species under different temperatures.
    Spectroscopic Studies on the Interactions of Water-soluble Porphyrins with Nucleic Acids
    HUANG Cheng-Zhi, LI Ke-An, TONG Shen-Yang
    1997, 18(4):  525-529. 
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    This paper presents the spectroscopic features of the interactions of two por-phyrins, meso-tetrakis (4-trimethylaminoniumphenyl )porphine (TAPP) and meso-tetrakls (N-methyl-4-pyridiniumyl)porphyrin (TMpyP-4 ) with nucleic aclds.Spectra involve electron ab-sorption, fluorescence and resonance light-scattering.The studies of absorption and fluores-cence show that the two porphyrins share common features when they interact with nucleicacids.That is, when the molar ratlo of porphyrins to nuclelc acids, R>0.25, nuclelc acidshave hypochromicity and fluorescence quenching effect on the Soret bands of the two por-phyrins;when R<0.25, new fluorescent products are formed.The difference of the interac-tions of the two porphyrins with nucleic acids can be distingushed by resonance light-scatter-ing spectra.Nucleic acids can strongly enhance the intensity of resonance light-scattering ofTAPP, but not of TMpyP-4.
    Multiresolution Analysis of Hyphenated Chromatographic Data
    SHEN Hai-Lin, WANG Ji-Hong, LIANG Yi-Zeng, CHEN Wen-Can
    1997, 18(4):  530-534. 
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    In this paper, multiresolution analysis(MA) based on orthonormal wavelet basesis introduced.Its applications in data compression and background eliminatlon of hyphenatedchromatographic data are discussed.The results show the proposed method can remove theinfluence of complex background successfully as well as compress data efficiently.Satisfacto-ry results from computer simulation and real analytical systems are achieved.
    Development and Application of Graphite-Teflon Composite Coating Electrode
    XU Hong-Ding, LUO Yun-Jing, ZOU Ming-Zhu
    1997, 18(4):  535-537. 
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    In this paper, the procedure of preparation of graphite-Teflon composite electrode(GTE) by coating was investigated.The coating consisted of a solid mixture 2.5 g(graphite 45%, Teflon 45% and PVC 10%) mixed with a solvent (THF: DMF=1:4 in volume) 0.8mL.Copper wires(=0.7 mm) were coated by the coating and heated at 200℃ for 5 min,and the GTEs were finished.They could be modified and changed into other metallic Tefloncomposite electrode only by electroplating in correspondent plating bath, such as mercury-cobalt-or copper-Teflon composite electrode.They had been applled to flow injection analy-sis by techniques of electrochemitry successfully.
    Simultaneous Determination of Fluorene, Acenaphthene,Anthracene and Perylene by Derivative Constant Energy Synchronous Fluorimetry
    LI Yao-Qun, SHI Ning, QIAN Fang, HUANG Xian-Zhi
    1997, 18(4):  538-540. 
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    The technique of derivative constant energy synchronous fluorimetry was intro-duced in this article.For mixture of fluorene, acenaphthene, anthracene and perylene, thedetection limit is 2.4, 17.1, 0.27, 0.043 ng/mL, respectively, when first-derivative con-stant energy synchronous fluorimetry is employed.The detectlon limit is 1.5, 15.0, 0.13,0.022 ng/mL, respectively, when second-derivative constant energy synchronous fluorlme-try is employed.In the method, four compounds can be simultaneously determined withoutany mutual interference.
    Manipulation of Electroosmotic Flow in Capillary Electrophoresis for Iodide and Iodate
    REN Hong-Xing, WU Ming-Jia
    1997, 18(4):  541-543. 
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    Manipulation of electroosmotic flow in capillary electrophoresis is an importantstep for separation of inorganic anions.The type and concentratlon of electroosmotic flowmodifier (OFM) exert a tremendous influence on the electroosmotic mobllity.ln the pres-ence of CTABas buffer solutions'pHvalues increase, the electroosmotic mobility becomeslower.At the same ionic strength, the buffer type affects the electroosmotic veloclty and themigration order for iodide and iodate.
    Studies on the Method of Leaps and Bounds Regression
    SHEN Qi, XU Lu, LI Hua
    1997, 18(4):  544-546. 
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    In this paper,we introduce the method of leaps and bounds regression which canbe used to select variables quickly and obtain the best regression models-These models con-tain one variable, two variables, three variables and so on-The results obtained by usingleaps and bounds regression were compared with those achieved by using stepwise regressionto lead to the conclusion that leaps and bounds regression is an effective method.
    Electrochemical Behavior of the Complex of Cobalt-Bipyridyl on Gold Electrode and Interaction of the Complex with Adenine
    ZHAO Guang-Chao, WANG Xue-Mei, CHEN Hong-Yuan
    1997, 18(4):  547-549. 
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    Electrochemical behavior of Co (bpy)32+ on gold electrode and interaction of thiscomplex with adenine was investigated.Voltammetric experiments indicated that the electro-chemistry of Co(bpy)32+ on gold electrode was quasi-reversible with one-electron transfer re-action in phosphate buffer(pH=7.0).The formal potential, E°'was 0.057 V.The electrontransfer rate constant, KS, was 1.43×10-2 cm/s.This property was characterized by spec-troelectrochemistry.Both anodic and cathodic peak potentials shifted to more positive valuesin the presence of adenine.In this case, E°'shifted to more positive potentials by 15 mV.The KS'descended about three times.The complex ratio was 1: 1.The complex constant was64.2 L/mol.The interaction was testified by electrochemistry and spectrum of adenine.
    Studies on Double Mannich Reaction of 3-Aryl-5-mercapto-1, 2, 4-triazoles
    WANG Zhong-Yi, YOU Tian-Pa, SHI Hai-Jian, SHI Hao-Xin
    1997, 18(4):  550-553. 
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    In this paper, thirteen new 3, 5-disubstltuted tetrahydro-s-triazolo [3'4-b][1'3,5]thiadiazines were prepared by double Mannich reaction in the presence of HCl-ethanol so-lution, arylamine-HCl and 37% aqueous formaldehyde solution or the condensation productof arylamine and para formaldehyde were reacted with 3-aryl-5-mercapto-1, 2, 4-triazole toform the title compounds at 45-65℃.The structure of these compounds were characterizedby elementary analysis, IR, 1H NMRand MS.Their antibactericidal activity against E.Col-i, B-Subtilis and S.Aureus were tested.
    The Spectroscopy Characteristics and the Second-order Nonlinear Optical Properties of Novel Azobenzene Molecules with Push-pull Structures
    YAN Xing-Zhong, XU Zhi-Ling, LUO Ting, YANG Pei-Qing, CAI Zhi-Gang
    1997, 18(4):  554-558. 
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    In this paper, the spectroscopy characteristics and the second-order nonlinear op-tical properties of a series of push-pull chromorphores (R-HANB) based on 4'-bis (N, N-hydroxyethylene)imino-4-nitro azobenzene were studied.R-HANBwere classified as pseu-do-stilbene type molecules, which possess ultrafast photoresponsive time scale.The intensi-ties of the second-order harmonic generation of R-HANBpowder were mostly in the intensehigher than that of Disperse Red 1, while their composite values of first hyperpolarlizabilitiesand ground state permanent dipole monents were in the order of >3.4×10-82 C2m4/V2.Thesecond harmonic coefficients for the poled R-HANB-doped PMMAfilms were in the orderof >7.2×10-19 4/V.The variation of these properties of R-HANBwas explained well bythe electron and steric effects of substituents.
    Synthesis of Glycerolipid Conjugates of Germatrane
    CHEN Ru-Yu, ZHANG Cheng-Xiang, ZHANG Zhong-Biao, LI Feng-Fu
    1997, 18(4):  559-562. 
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    The synthesis of glycerolipid conjugates of germatranes is reported.The strategyfor the synthesis using DCCas the condensating agent and pyridine as the catalyst in a con-densation reaction resulted in the target compounds.Both conditions and mechanism of thecondensation reaction were studied.The structures of the compounds were confirmed by1H NMR, IRand elementary analyses.
    The Synthesis of α,β-Dimethylanhydracetonebenzil
    LIU Zong-Lin, LIU Xiao-Ling
    1997, 18(4):  563-566. 
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    Two improved methods were worked out for the preparation of α,β-dimethylanhy-dracetonebenzil (Ⅰ) by condensation of benzil with 3-pentanone in the presence of KOHasthe catalyst.In method 1, the condensation was carried out with a 3 h stirring in ethanol atroom temperature.After keeping the reaction vessel to stand at room temperature for 3days, the product ⅠAobtained was demonstrated to be a mixture of two pairs of enan-tiomers.But in method 2, the solvent was changed from ethanol to benzene with an additionof suitable amount of polyethyIene glycol PEG-400.After refluxing the mixture for 3 h, theproduct ⅠA'obtained was proved only one pair of enantiomers.When ⅠA and ⅠA'were de-hydrated by heating with Ac2O-H2SO4 separately, both of them formed the same compound3, 4-dipheny1-2, 5-dimethyl cyclopentadienone (Ⅱ).The constituents of ⅠA'ⅠA'and Ⅱwere confirmed mainly by 1H NMRand IR.Finally, it was suggested that ⅠAbe c0nsistedof about equal amount of dl-erythro-Ⅰ and dl-threo-Ⅰ,while ⅠA'is only dl-erythro-Ⅰ.
    Epoxidation of Unfunctionalized Olefins Catalyzed by Unsymmetric Schiff-base-Mn(Ⅲ) Complexes
    DU Xiang-Dong, YU Xian-Da
    1997, 18(4):  567-570. 
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    The selective epoxidation of unfunctionalized olefins (styrene, cyclohexene,a-methylstyrene) catalyzed by synthesized unsymmetric Schiff-base-Mn (Ⅲ) complexesMn(CBP-phen-XSal)Cl [X = H, Cl, Br, NO2, CH3, OCH3] and the symmetric analogsMn(CBP-R-CBP)Y[R =CH2CH2, CH (CH3)CH2, C6H4; Y=Cl, OAc] was investigated un-der mild conditions with iodosylbenzene as the terminal oxidant.The results show that theunsymmetric complexes Mn(Ⅲ) (CBP-phen-XSal)Cl is an effective system in catalytically se-lective olefin-epoxidation; the smaller the binding energy of Mn(Ⅲ), the more effective inepoxidation; the highest epoxidation yields of the mentioned three olefins are 73%, 100%and 92% respectively.
    Selectivity of the Epoxidation Reaction of Dimethyldioxirane with Carbon Carbon Double Bonds in Some Natural Products
    SUN Rong-Qi, LIN Tong, HUANG De-Yin, WU Da-Jun, XUE Zhong-Hua, CHEN Jian-Cun
    1997, 18(4):  571-573. 
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    The acetone solution of dimethyldioxirane was prepared with caroate (KHSO5) andacetone.This solution can be kept at low temperature(-20℃) for days.It is much conve-nient to use the oxidant for the epoxidation of carbon carbon double bonds in some unsaturat-ed natural products.Five unsaturated compounds were oxidized to the corresponding epox-ides with dimethyldioxirane and the reaction selectivity was discussed.
    Using Molecular Graphics, Molecular Mechanics, Quantum Chemistry and Electrostatic Potential Method to Study Structure-Property Relationship on Pesticides(X) ──Study on Internal Rotation Passage in Sulfonylurea Molecule by Molecular Mechanics Method
    LIU Ai-Lin, CAO Wei, LAI Cheng-Ming, YUAN Man-Xue, ZHANG Jin-Pei, LIN Shao-Fan, LI Zheng-Ming
    1997, 18(4):  574-576. 
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    In this paper, we have disussed the internal rotation in sulfonylurea molecules,which belong to high active and low toxic herbicides and take the form of conformational iso-mers in their crystal structures.In order to understand the formation of their enantimers, weobtained a series of data of molecular energy of different conformation by using the molecularmechanics method and the stepwise rotation single-bond method.We found out the lowestinternal rotation passage and obtained the energy barrier of hindered rotation which is less 60kJ/mol.This result shows that there is a lower energy passage to exchange the conforma-tional isomers of these molecules, so exchanging the different conformational isomers is notvery difficult.
    In-situ Electrochemical Atomic Force Microscopy Studies of Nucleation of Single Nucleus on Microelectrodes
    CAI Xiong-Wei, XIE Zhao-Xiong, MAO Bing-Wei
    1997, 18(4):  577-580. 
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    The electrochemical nucleation and growth of silver single nucleus on glassy car-bon microelectrode have been monitored in-situ with electrochemical atomic force microscopy(ECAFM) at different stages.The AFMresults show that the silver single nucleus forms atthe edge of the glassy carbon and grows to form a crystallite with (100) facet preferentiallydominated.It is confirmed that the nucleation process strongly relies on the condition ofglassy carbon substrate.Multiple nuclei are formed on the substrate with nucleation historybut single nucleus can be achieved on the same substrate after the application of a special"purging" method.The work is the first example for the real time observation of nucleationand growth of a single nucleus on a microelectrode and for the application of ECAFMto thestudies of microelectrode systems.Comparison of the work with previous ex-situ measure-ments are given.The work also demonstrates a possible way to obtain a single crystal micro-electrode which c0uld be valuable for various purposes.
    Research Method for Kinetics of Chemical Reactions ──Self-function Regression Method and Its Applications
    ZENG Xian-Cheng, MENG Xiang-Guang, ZHANG Yuan-Qin, CHEN Min-Zhu, QIN Zi-Ming, HU Qi-Shan
    1997, 18(4):  581-585. 
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    Aself-function recursion equation,fi=b1fi+1+b2fi+2 can be obtained after theperfect nonlinear funtion,f(t)=A+Be-k1l+Ce-k2l has been transformed.Through treatingthe self-function recursion equation with the theory of regression analysis, a novel researchmethod for the kinetics of chemical reactions, self-function regression method, has been de-veloped.This method can be applied not only to thermokinetic studies, but also to ultravio-let spectrophotometry for treating kinetics of complex reactions.As a result of treating ther-mogram equation of the first order reaction with Laplace transform, the thermogramequation can be expressed as.Δ=A (e-k1l——e-kt.The rate constant of the first order reaction,k1, and the cooling constant of thermokinetic system, k, can be obtained at the same timewith the self-function regression method.In order to test the validity of this method, thesaponifications of ethyl acetate and ethyl butyrate have been studied at 25℃ in aqueous solu-tion.The rate constants calculated with this method are in agreement with th0se in litera-tures, and therefore the self-function regression method is correct in deed.
    Studies of Xanthine Oxidation by Xanthine Oxidase Using Microcalorimetry
    LIANG Yi, WANG Cun-Xin, ZOU Guo-Lin, QU Song-Sheng, WU Yuan-Xin, LI Ding-Huo
    1997, 18(4):  586-589. 
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    Thermokinetic model of two-parameter initial rate method for faster enzyme-cat-alyzed reactions has been suggested based on the two-parameter theoretical model of conduc-tion calorimeter.Thermokinetics of xanthine oxidation catalyzed by xanthine oxidase wasstudied using microcalorimetry.This faster enzyme-catalyzed reaction obeyed the Michaelis-Menten kinetics, and at 298.15 Kand pH 7.5, the Michaelis constant(Km) for xanthine was1.04×10-3 mol·L-1, which is in agreement with that given in the literature.
    INDO and Localized Molecular Orbitals Study on the Structures of Cr2(O2CR)4L2 Complexes
    LI Qian-Shu, HU Xu-Guang, QU Hong
    1997, 18(4):  590-594. 
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    The structures of Cr2(O2CCH3)4 (gas state and solid state) and [Cr=(CO3)4·(H2O)2]4-have been investigated by using INDOsemiexperiential method and the Edmiston-Ruedenberg localization method.The relationship between d four-fold bond and bond lengthhas been analyzed and it can be found that there exit four-fold bonds between the tlyo Cratoms in Cr2 (O2CCH3)4 (gas state ) and [Cr2 (CO3)4 (H2O)2]4-.The quantum chemical pic-tures of d four-fold bonds are given directly.The similarities and differences of the bondingproperties of these complexes are discussed and it can be explained that Cr2 (O2CCH3)4 (gasstate) interacts easily with ligands to form a new complex due to empty p orbitals exiting onthe along Cr-Cr bond axis.
    Studies and Applications of Corrosion Inhibitor IMC-80
    CAO Dian-Zhen, YANG Huai-Yu, ZHU Ying-Jian, GAO Hong-Lei, CAO Jia-Shou, WAN Fang-Lin, CHEN Jia-Jian, WANG Guo-Bin, CHUI Zhong-Xing, GUO Xue一Hui
    1997, 18(4):  595-599. 
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    Aseries of compounds, with amine and alkynyl-oxygen alkyl groups in the molec-ular structure, were synthesized.Based on the synthesized compounds, a new corrosion in-hibitor IMC-80 was formulated and its per formance was investigated using weight loss andelectrochemical methods in brine saturated with CO2 and hydrochloric acid solution.The re-sults show that the inhibitor has a higher inhibition effeciency in acid medium, oil well,sewage and water soluted a little H2Sand CO2. The inhibitor has been used to protect oilwell and its pipeline from corrosion, the inhibition effeciency is more than that of CI-203made in U.S.A.
    Enhancing Stability of Vitamine C in CTAB/n-C5H11OH/H2O System
    GUO Rong, SONG Gen-Ping, YU Wei-Li
    1997, 18(4):  600-604. 
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    Vitamine C(VC) was solubilized in the inner region in the interphase of O/WandW/Omicroemulsion, but n-C5H11 OHwas solubilited in the outer region.The water pene-trating into the interphase or amphiphilic layer was prevented from VCby n-C5H11OHso thatthe stability of VCwas enhanced.The mechanism of enhancing stability of VCin O/WandW/Omicroemulsion droplets was proved by the enhancing stabllity of VCin lamellar liquidcrystal.
    Studies on the Isothemal Solubilities of the Quaternary System KCl-K2SO4-CO(NH2)2-H2O at 25℃
    ZHANG Feng-Xing, WEI Xiao-Lan, ZHOU Xia, GUO Zhi-Zhen
    1997, 18(4):  605-608. 
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    The isothermal solubilities and the refraction indices, densities of the saturatedsolutions in the quaternary system KCl-K2SO4-CO(NH2)2-H2Owere investigated at 25℃ forthe first time.The isograms of the refraction indices, densities and water-content of the sat-urated solutions corresponding to K2SO4 have been obtained.The phase diagram of the qua-ternary system is simple cutectic type,in which there is a triple saturated point, KCl 14.06,K2SO4 0.51, CO(NH2)2 47.05, H2O38.88 (mass fraction×102).
    Theoretical Studies on the Nonlinear Optical Properties of Novel Diacetylene Derivatives with Azobenzene Substituents
    REN Ai-Min, FENG Ji-Kang, XIAO Chang-Yong, SUN Chia-Chung, WANG Jiang-Hong, YU Cong-Xuan
    1997, 18(4):  609-614. 
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    On the basis of AM1 and ZINDOmethods, according to the sum-over-states ex-pression, the nonlinear second-and third-order optical susceptibilities Pijk and Yijkl of noveldiacetylene derivatives with azobenzene substituents have been calculated.Thesystematic theoretical studies have been performed, that is on the basis of(这里有图片19970427-609-2.gif)introducing donor N (CH3 )2 onthe left side and acceptor CH2OHor(这里有图片19970427-609-3.gif) on the right side of above molecule,the rule of variations of β and γ has been examined.The regularity summarized from the cal-culated results has been explained micromechanically.
    Electron Transfer of Horseradish Peroxidase Entrapped in Poly-o-phenylenediamine Membrane Electrode
    CHEN Bin-Hui, ZHU Kan, WU Hui-Huang, ZHANG Ying-Zhou
    1997, 18(4):  615-620. 
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    The poly-o-phenylenediamine membrane electrode containing horseradish peroxi-dase was prepared by means of the electrochemical immobilization of enzyme, and thevoltammetric behavior of the resulting enzyme electrode and its bioelectrocatalysis to hydro-gen peroxide reduction was studied.It was found that the direct electron tansfer between theenzyme and the polymer matrix takes place in the biocatalytic processes.For the newly pre-pared enzyme electrode, however, the oligomers, which are formed during the polymeriza-tion of o-phenylenediamine and then incorporated in the enzyme membrane, can play a role ofelectron transfer mediators to accelerate the regeneration of the oxidized enzyme.From thefitting of experimental current response curves, it can be found that the change in the regen-eration rates of the oxidized enzyme with the electrode potentials obeys apparantly the Tafelrelationship.The procedure in the measurement of kinetic parameters for enzyme reactionswas suggested.
    Studies on Photoelectrochemical Properties of Porous Silicon
    WANG Bao-Hui, WANG De-Jun, LI Tie-Jin
    1997, 18(4):  621-624. 
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    The charge transfer and photoelectric properties of porous silicon were investigat-ed by photoelectrochemical techniques.The results show that the porous silicon fabricated bysingle crystalline p-Si exhibits photoelectric properties of p-type semiconductors with a high-er photocurrent than the original silicon.Due to the unique surface structure, the porous sili-con has a particular photocurrent spectrum.This is attributed to the photocharge-trappingeffect of surface states in the porous silicon.
    Studies of Surface Acidity and Basicity of the Attapulgite
    WANG Qing-Gen, TU Mai, WANG Wei-Dong, SHEN Jian-Yi
    1997, 18(4):  625-627. 
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    Attapulgite with the composition of [MgAlFe]5Si8O20(OH)2(OH)2(OH2)44H2Ohas beenwidely used as catalyst or catalyst support in various catalytic reactions.The surface acidityand basicity of attapulgite should play an important role, in particular, in the acid/base cat-alyzed reactions.In this paper, a Tian-Calvet type microcalorimeter was used to measurequantitatively the number and strength of acid/base sites on the surface of attapulgite sam-ple.The acid/base properties of the sample were also investigated with infrared spectroscopyand test reaction of isopropanol dehydration.The results indicated that the attapulgite dis-played the acidity with initial differential NH3 adsorption heat of 130kJ/mol and saturatedNHs coverge of 1.5 pmol/m2.The strength distributions of surface acid sites on attapulgiteand the calorometric results suggested that the attapulgite possessed only a few(<0.1 μmol/m2) very weak base sites with CO2 adsorption heat lower than 5kJ/mol.The infrared spec-troscopy revealed that the attapulgite had both Brdnsted and Lewis acid sites-Moreover, theLewis acid sites(1619 cm-1 ) were stronger than 90kJ/mol characteric of the NH, adsorptionheat.In summary, the attapulgite was a weak solid acid without any basicity compared tothe γ-Al2O3。
    Synthesis and Structural Studies of Polyamide-46(Ⅱ)──Characterization and Structure of Polyamide-46
    WANG Qun, SHAO Zheng-Zhong, YU Tong-Yin
    1997, 18(4):  628-632. 
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    Polyamide-46 prepared by interfacial and solution-solid-phase polycondensationwas characterized by FTIR, 1H NMRand DSC.The structure of the polymer in the con-densed state was studied using WAXSand STM.
    An Apparent Kinetics Study of Synthesizing Poly(phenylene sulfide) in N-Methyl Pyrrolidone
    HE Jian-Ye, HE Jiang-Chuan, HUANG Guang-Lin
    1997, 18(4):  633-636. 
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    The apparent kinetics of synthesizing of poly (phenylene sulfide) (PPS) fromp-dichlorobenzene and sodium sulfide has been investigated at 220℃ and 250℃ inN-methylpyrrolidone.The rates of sodium chloride generated and sodium sulfide consumedin a series of reaction time in polymerization reaction were determined and treated by meansof least-square method.It was found that the polycondensation process is dominated by acondensation reaction which, in turn, is followed by a self-polycondensation of ABtype(Eqs.2, 3).Thus an apparent kinetics expression of the polymerization was found as 1/(1-Pnacl+Pna2s)=c0kt+11and the apparent rate constants of the two temperatures are 4.5×10-4 3.0×10-3respectively, and the apparent active energy was estimated as134 kJ/mol.
    Effect of Poly-ε-caprolactone Hyperdispersants on the Rheological Behavior and Dispersion Stability of Magnetic Dispersion
    ZHANG Xue-Li, WANG Zheng-Dong, HU Li-Ming
    1997, 18(4):  637-641. 
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    The rheological behavior and dispersion stability of magnetic powder suspensionwere studied.With the aid of hyperdispersants having poly (ε-caprolactone) as solvatablechian, the viscosity of the suspension was lowered and the dispersion stability was improvedobviously.The effect of the hyperdispersants was the result of both the type of the anchor-ing group and the molecular weight of the solvable chain.When the molecular weight of thesolvatable chain is 700 and the anchoring group is the mixture of carboxyl and tertiaryamine, the hyperdispersant, has the best effectiveness.
    Compositional Heterogeneity of Ethylene Terephthalate-Ethylene Oxide Segmented Copolymer with Long Soft Segment
    LUO Xiao-Lie, ZHANG Xiao-Yun, WANG Ming-Tai, MA De-Zhu
    1997, 18(4):  642-646. 
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    The series of ethylene terephthalate-ethylene oxide segmented copolymers withdifferent long soft segments and different hard segment contents have been synthesized.Thehard segment contents are measured by 1H NMR.Four PET-PEOsegmented copolymerswere separated into soluble and insoluble parts in chloroform.The results have revealed avery evident compositional heterogeneity in these four samples,which depends on the molec-ular weight of soft segment and hard segment content.Simultaneously the melting and ther-mal spectra of the four PET-PEOsegmented copolymers were obtained by DSC.The solubleand insoluble parts have shown the quite different crystallizability both for soft and hard seg-ments, which has the good correspondence with the compositional heterogeneity.
    XPS Study of Static Adsorption of HPAM on SiO2
    YANG Ji-Ping, LI Hui-Sheng, HUANG Peng-Cheng
    1997, 18(4):  647-651. 
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    The relationship between the concentration of partially hydrolyzed polyacrylamide(HPAM) and the quantity of HPAMadsorbed on the SiO2 surface was studied.The X-rayphotoelectron spectroscopy(XPS) was used to investigate the interaction between the poly-mer molecules and the adsorbent surface.The experimental results show that the adsorptionof HPAMon SiO2 surface is consistent with Langmuir model.XPSanalysis of the samplessurface shows that the N/Si atomic concentration ratio reflects the quantity of HPAMad-sorbed on the SiO2 surface, and the increase of N15, binding energy is related to the formationof the hydrogen-bonding between the HPAMmolecules and the SiO2 surface.
    A New Method for the Synthesis of the Conjugated Polymer──Poly (N, N-dimethylaniline)
    ZHENG Hai-Peng, ZHANG Rui-Feng, SHEN Jia-Cong
    1997, 18(4):  652-654. 
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    This paper described a new synthetic method of a novel poly(phenylene) deriva-tive— poly(N, N-dimethylaniline) (PDMA) by forming a CTcomplex with monomer N,N-dimethylaniline and tetrachloro-p-quinone (TCQ).The CTcomplex was further studiedwhich could not only protect the side group (N,N-dimethyl), but also afford relatively lowenergy of activation in polymerization.The resulted polymer PDMAwas characterized by el-ementary analysis, FTIR, 1H NMRand UV-Vis spectra.The relationship between the spec-tra and its structure was also discussed.
    Synthesis and Characterization of Soluble Fluorescent Poly (aryl ether ketone)s
    RUAN Ru-Xiang, CHEN Chun-Hai, ZHOU Hong-Wei, WANG Jun-Zuo, WU Zhong-Wen
    1997, 18(4):  655-657. 
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    The soluble fluorescent poly(aryl ether ketone) polymers were synthesized by nu-cleophilic substitution reaction of diphenol and aromatic benzene substituted by active fluo-rine.These polymers have glassy transition temperature of 210-230℃, The polymers insolid state and their solutions are all of fluorescenre with the color of green and their maxi-mum excitation and emission wavelengths are 420 nm and 487 nm respectively.The fluores-cent strengths of the polymer solution damp with time delayance, but restitute when heatedto 220℃ for several minutes.
    A New Approach to the Synthesis of 1, 4, 7, 10-Tetraazacyclododecane
    WEI Jun-Fa, ZHUO Ren-Xi, YAN Guo-Ping, DU Po
    1997, 18(4):  658-660. 
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    Anew and simplified method for synthesis 1, 4, 7, 10-tetraazacyclododecane (cy-clen) has been proposed by two steps in this paper.The first step deals with cyclic condensa-tion of triethylenetetramine and diethyl oxalate in methanolic solution, giving the twelve-numbered cyclic oxamide, i.e., 1, 4, 7,10-tetraazacyclododecane-2, 3-dione.The pure prod-uct was obtained as a crystalline precipitate in 39% yield on addition of ethanol to the con-centrated solution of the reaction mixture.Subsequently, in the second step, the cyclic ox-amide was reduced in THFwith diborane produced in situ fr6m potassium borohydride andboron trifluoride etherate and extracted by CH2Cl2 from the basic aqueous solution of the sol-vent free residue, giving cyclen in 56% yield after removing the solvent.
    Determination of the Dissociation Equilibrium Constant and Conjugated Free Energy for the Bilirubin-Albumin Complex
    YU Yi-Hua, YUAN Zhi, HE Bing-Lin, GU Han-Qing
    1997, 18(4):  661-663. 
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    Crosslinked chitosan resin is a new type of billrubin adsorbent.It can adsorb boththe conjugated and unconjugated bilirubin-Adsorption experiments were performed byadding the resins to previously prepared bilirubin solution, with different concentrations ofbilirubin and BSA.The dissociation equilibrium constant and conJugated free energy for thebilirubin-albumin complex were obtained according to plot.
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