Loading...
CJCU

Table of Content

    24 September 1997, Volume 18 Issue 9
    Previous Issue    Next Issue
    Articles
    Studies on the Crystallization Behavior of Zeolite Silicalite－1 in(TPA)2O-Na2O-SiO2－H2O System(Ⅱ)──Low Temperature Preparation and Characterization of Fine Crystals
    WU Ai－Mei, LONG Ying－Cai
    1997, 18(9):  1407-1413. 
    Asbtract ( )   PDF (584KB) ( )  
    Related Articles | Metrics
    Zeolite slllcallte－1 with a high crystallinity was synthesized in the system of(TPA)2O-Na2O-SiO2－H2Oat 60℃ by using fumed silica－silica aerogel(Ⅰ) or silica sol(Ⅱ)as the silicon source. The crystal size of products obtained is 0.2 μm in(Ⅰ) and 0.45μm in(Ⅱ) measured by SEM, and 0.02μm determined by the method of XRDpeak broadness.Incomparison with the properties of sample Aprepared at 180℃,the fine crystals Bsynthe－sized at 60℃ possess some characters which the nanometer particles have.The adsorption ofn－hexane on sample Bis abnormaly high.Investigated by XRD, FT－IR, 29Si MAS NMRandTG/DTG/DTA, the temperatures for structural damage and for monoclinic/orthorhombicspmmetrt transformation ofsample Bare obviously lower than that of sample A. The de－fects of Si-OHin sample Bare much more than those in sample A.
    Research on Obtaining the Refined X-ray Powder Diffraction Pattern and Indices of [Co(NH3)5Br]Br2
    WU Hong-Xiang, MA Li-Dun, SHEN Xiao-Liang, SHI Guo-Shun
    1997, 18(9):  1414-1419. 
    Asbtract ( )   PDF (468KB) ( )  
    Related Articles | Metrics
    In this paper, the refined X-ray powder diffraction pattern and its indices werepresented according to the requirements on ah initio structure determination from powderdiffraction data. Instrumental conditions, sample preparation methods and standardreference materials' application were discussed. The questions and solutions on indexing had beensummed up. The refined unit cell parameters for orthorhomblc system of the title compoundare: a=1. 3710(1) um, b=1. 0715(1) um, c=0. 6947(1) um, V=1. 0206(1)nm3, Z=4,Dx= 2.50g·cm-3, F30=81. (0.0071, 52), M20=41. Extinction conditions indicate that thespace group is Puma or Pn21a.
    Studies on Phase Chemistry of Meyer's Reaction in Alkali Metal Bromide/Rare Earth Metal Tribromide Systems(Ⅱ)──A Study on Phase Diagrams of CsBr-REBr3-13%HBr──H2O Quaternary System(25℃, RE=La, Pr, Nd,Sm)
    WANG Hui, LI Ya-Hong, RAN Xin-Quan, CHEN Pei-Yan
    1997, 18(9):  1420-1424. 
    Asbtract ( )   PDF (362KB) ( )  
    Related Articles | Metrics
    Phase chemistry of CsBr-NdBr3-13%HBr──H2Oquaternary system at 25℃ wasstudied. The characteristics of the light rare earth compounds is very similar and the"bicomponent effect" of the light rare earth is very obvious by comparing the phase chemicalbehavior and the relation of these quaternary systems with each other. Meanwhile, a new solidreaction is designed according to the phase relation and new compounds are synthesizedaccording to the design.
    Preparation of Phosphors MBPO5: Eu2+ and MBPO5: Yb2+ in Air
    JING Hai-Qiang, WU Guo-Qing, DU Bao-Shi
    1997, 18(9):  1425-1428. 
    Asbtract ( )   PDF (329KB) ( )  
    Related Articles | Metrics
    MBPO5: RE2+ (M = Ca, Sr, Ba; RE= Eu, Yb) were synthesized with RE2O3,H3BO3, (NH4)2HPO4 and MCO3 as the starting materials in air, instead of preparing them inH2/N2 atmosphere. The peaks in their excitation and emission fluorescence spectra as well ashalf-widths of emission were measured. The results show that it is possible to preparedivalent Eu and Yb ions activated phosphors in air, if the crystal structure of the matrix enablesthese divalent ions to be stable in the light of its geometric factors and if the matrix itselfenables reducing trivalent Eu and Yb to be divalent.
    Single Crystal Growth and Spectroscopic Properties of KZnF3: Eu3+
    AN Yong-Lin, SHI Chun-Shan, NI Jia-Zhuan
    1997, 18(9):  1429-1431. 
    Asbtract ( )   PDF (253KB) ( )  
    Related Articles | Metrics
    Single crystal of KZnF3: Eu3+ has been grown by means of Bridgman-Stockbargertechnique in Ar atmosphere. The emission and excitation spectra of europium ion weremeasured. The results show that a small amount of Eu2+ exists in the crystal. The existence ofEu2+ ions was also confirmed by ESRdata. The valence change of Eu ions during the crystalgrowth is due to unequivalent substitution of Eu3+ ions for the lattice ions. The sites possiblyoccupied by Eu ions in this crystal were also discussed.
    Studies on Application of Microwave Heating Techniques for the Solid State Reactions of Coordination Compounds(Ⅰ)── Synthesis of Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ) Complexes by Solid State Reactions Under Microwave
    JIA Dian-Zeng, YANG Li-Xin, XIA Xi, XIN Xin-Quan
    1997, 18(9):  1432-1435. 
    Asbtract ( )   PDF (309KB) ( )  
    Related Articles | Metrics
    Solid state reactions of the transition metal acetates such as Co (OAc)2·4H2O,Ni(OAc)2·4H2O,Cu (OAc)2·H2Owith organic compounds such as amino acids, Schiffbases, β-diketon, 8-hydroxyquinoline have been investigated in the microwave oven. It isshown that the coordination compounds can be synthesized by solid state reactions up to 50times faster in a microwave oven than by conventional techniques. The results suggest asignificant Potential value of microwave heating in solid state coordination chemistry.
    Synthesis of Nanocrystalline γ-MnO2 by Hydrothermal Method and Its Characterization
    LI Ya-Dong, LI Cheng-Wei, LI Long-Quan, QIAN Yi-Tai
    1997, 18(9):  1436-1437. 
    Asbtract ( )   PDF (167KB) ( )  
    Related Articles | Metrics
    γ-MnO2 nanocrystalline was synthesized by hydrothermal method. XRD, TG,DTAand TEa were used to characterize the MnO2, nanocrystalline and its precursor. Theresults indicate that the powder obtained form crystallizing at 400℃ was γ-MnO2 with size inthe range of 5-10nm. When the powders were crystallized at 500℃, they agglomerated tobe spherical particles with a size about 50 nm. The thermal sensitivity of the MnO2nanocrystalline was also studied.
    Kinetics and Mechanism of Pyrogallol Autoxidation
    YUAN Zhuo-Bin, GAO Ruo-Mei
    1997, 18(9):  1438-1441. 
    Asbtract ( )   PDF (426KB) ( )  
    Related Articles | Metrics
    The kinetics of pyrogallol autooxidation has been studied by single-sweeposcillopolarography in Tris-HCIbuffer soluton in the PHrange 7. 20-9. 10. The reaction wasfirst order to pyrogallol in the presence of excess dissolved O2. The focus was put onpyrogallol autooxidation with products of semiquinone free radical and active oxygen. Amechanism was presented which explains the increase in rate with increasing PHby postulating thatH2PYR-has a greater reactivity with dissolved O2 than H3PYR. The derived rate law is ingood agreement with the experimental observations. The paper also presented a new assayfor superoxlde dismutase and antioxidant activity of pharmaceuticals.
    Preparation and Characterization of Zeolite Membrane Gas-liquid Capillary Column
    KOU Deng-Min, YUN Xi-Qin, LU Xue-Mei, LI Su-Qi
    1997, 18(9):  1442-1446. 
    Asbtract ( )   PDF (361KB) ( )  
    Related Articles | Metrics
    Various stationary phases with different polarity have been coated evenly on thesurface of in Situ synthesized zeolite membrane. The zeolite membrane modified gas columnhas been prepared. Some characteristics of this new kind of column such as columnefficiency, separating power, quantitative accuracy and thermostability of stationary phasehave been evaluated. Large-bore zeolite membrane SCOTcolumn has also been parpared inorder to replace the packed column in regular analysis. its column capacity and separationpower under the condition of split stream and no supplemental gas have been studied.
    Chiral Recognition of Cyclodextrin Supramolecular System──Simultaneous Fluorescence Determination of D,L-Tryptophan Enantiomer by Chiral Recognition of β-Cyclodextrin
    XIE Jian-Wei, ZHAI Yan-Qiang, YANG Zao-Ping, RUAN Jin-Xiu
    1997, 18(9):  1447-1449. 
    Asbtract ( )   PDF (332KB) ( )  
    Related Articles | Metrics
    The paper reports the simultaneous fluorescence determination of D,L-tryptophanenantiomer by chiral recognition of β-cyclodextrin for the first time. Chiral discrimination isobserved for fluorescence emission of D- and L-tryptophan when complexed toβ-cyclodextrin, and is significantly related to reaction temperature, time and PH. The proposedenantiomeric resolution of D- and L-tryptophan is based on the non-fluorescellce emission ofLtryptophan in β-cyclodextrln solution at 35℃ and after 24 h standing by. The fluorescenceemission and absorbance of L-tryptophan disappear with the Increase of β-cyclodextrin at 35℃ and 24 h standing by, where as it is not observed for D-tryptophan. The detection limitsare 3.1×10-8 mol/Lfor D-tryptophan and 2.7 ×10-7 mol/Lfor L-tryptophan, respectively,with a RSDof 1. 0%-2. 6% (n=7). The method has been shown to be accurate with a ratioof 2%(molar ratio) of one enantiomer in the presence of the other. The observed pseudofirst-order rate constant is calculated. The reaction mechanism has been discussed usingpyrene as a fluorescence probe.
    Studies on the Zeolite Membrane PLOT Column by in situ Synthesis
    KOU Deng-Min, YUN Xi-Qin, LU Xue-Mei, FU Chun-Xiao, PEI Wei
    1997, 18(9):  1450-1452. 
    Asbtract ( )   PDF (317KB) ( )  
    Related Articles | Metrics
    The preparation of the zeolite membrane PLOTcapillary column by in situsynthesis was described. The advantages of this new kind of column were discussed. Someanalytical application to the separation of various mixtures on zeolite membrane PLOTcolumncompared with those on the coated zeolite PLOTcolumn were reported. The reproducibility ofthe zeolite membrane PLOTcolumn were evaluated. It has been found that the zeolitemembrane obtained is more homogeneous and thinner than coated zeolite. The zeolite membranePLOTcolumn can shorten the analysis time, make the peak more symmetric, allowseparation at lower temperature and broaden the range of utilization of zeolites in GC.
    Separation and Determination of Organic Acids in Foods by Capillary Electrophoresis with indirect UV Detection
    FU Xiao-Yun, LU Jian-De, CHEN Yao-Zu
    1997, 18(9):  1453-1455. 
    Asbtract ( )   PDF (337KB) ( )  
    Related Articles | Metrics
    Capillary electrophoresis(CE) with indirect UVdetection method for theseparation and determination of several organic acids commonly found in foods were developed.Effects of PH, background electrolytes and electroosmotic flow modifiers on separation wereinvestigated. The carrier electrolyte PHplayed an important role in the separation of organicacids. All analytes could be separated in one run by performing CEwith 5. 0 mmol/Lphthalate-3.0 mmol/Ldodecyl trimethyl ammonium chloride (DTAC) at pH=7. 0 within 6 min.The reproducibllity(RSD) of the method is less than 0.17% for migration time and 4. 2% forthe peak area (n=8). Linearity was observed more than one order between 1 and 80 mg/L.The detection limits are obtained from 0. 5 to 5. 0 mg/L. Avariety of matrix samples such aswine, juices and soy sauce were determined by the method. The recoveries were in the rangeof 95 %-102 %.
    Determination of DNA by a Self-quenching Fluorescence Probe
    ZHAO Yi-Bing, WANG Dong-Yuan, XU Ke-Wei, GUO Xiang-Qun, XU Jin-Gou
    1997, 18(9):  1456-1458. 
    Asbtract ( )   PDF (255KB) ( )  
    Related Articles | Metrics
    This paper describes a new fluorescence probe technique for the determination ofDNA, which is based on a self-quenching course of high concentration of o-hydroxybenzoicacid or o-aminobenzoic acid. Studies involving calf thymus (CT) DNA, salmon (SM) DNAand herring sperm(HS) DNArevealed that the differential value of fluorescence intensity inthe presence and absence of nucleic acid was proportional to the concentration of nucleic overthe range of about 15 ng/mL 6.0μg/mL.
    Studies on the interaction of Photosensitizers and Glucose Oxidase Using Capillary Electrophoresis
    HU Ping, LUO Guo-An, WANG Ru-Ji, DONG Run-An, SONG Xin-Qi
    1997, 18(9):  1459-1461. 
    Asbtract ( )   PDF (233KB) ( )  
    Related Articles | Metrics
    The interaction of glucose oxidase (GOD) and four photosensitizers, ZnpcS4,ZnPc(NHCH2COOH)4, CIAIPcS, and porphyrine-like, were monitored by capillaryelectrophoresis. GOD, its degenerated products and photosensitizers were simultaneouslyseparated in a buffer of 300 mmol/Lborate at PH8.5 on a commercial CEinstrument. Bycomparison of the electropherograms of GODas well as the mixture of GODand photosensitizerswithout/with irradiation of different time, it was found that photosensitized oxidationsbetween GODand different photosensitizers have different reaction mechanisms and kinetics.
    Synthesis of High Efficiency Packing and Using for Recombinant Human Interferons Separation in High-performance Hydrophobic Interaction Chromatography
    GUO Li-An, ZHU Bao-Quan
    1997, 18(9):  1462-1464. 
    Asbtract ( )   PDF (250KB) ( )  
    Related Articles | Metrics
    The synthesis of packing of oxygen-ethane as end-ligand bonded to silica andseparation for recombinant human interferons(rhIFN) in high-performance hydrophobicinteraction chromatography has been studied in this paper. It was showed that the packingsynthesized was not only suitable for separating standard proteins, but also for different rhIFNs,i. e., rhIFN-αAexpressed in yeast, rhIFN-αAand rh1FN-γ in E. colt. The purify of threerhIFNs purified by one-step HPHIC, which rhIFN-γ expressed in E. colt was recognized as80%, rhIFN-αAexpressed in yeast as 70%, and rhIFN-αAexpressed in E. colt as 30%, wasmore than that of other chromatography besides affinity chromatography.
    Synthesis and Characterization of Tricyclohexyl (phenyl, butyl)tin Arylthio(sulfinyl, sulfonyl) Acetates
    BAO Ming, HE Xiao-Zhi, HE Qing-Lin, ZHANG Zhan-Jin, LIU Bao-Dian
    1997, 18(9):  1465-1468. 
    Asbtract ( )   PDF (392KB) ( )  
    Related Articles | Metrics
    Twenty-two tricyclollexyl (phenyl, butyl) tin arylthio (sulfinyl, sulfonyl) acetateswere synthesized and their structures were characterized by elementary analysis, IR,1HNMR, MS, XPS. The data of iRand XPSindicate that these compounds are four-coordinated organotin compounds for the tricyclohexyltin arylthio (sulfinyl, sulfonyl)acetates andfive-coordinated, carboxylate-bridged poymers for the triphenyl (butyl)tin arylthio(sulfinyl,sulfonyl)acetates. Environmental sorption ability and bioconcentratlon ability for compoundswere predicted by calculating their n-octanol-water partition coefficients Kow.
    Studies on Carbohydrates (XXV)──Synthesis of Disaccharide Units of Serratia marcescens O4 Antigen Oligosaccharide
    ZHANG Ke-Qin, LI Shu-Chun, MAO Jian-Min, CHEN Hong-Ming, CAI Meng-Shen
    1997, 18(9):  1469-1473. 
    Asbtract ( )   PDF (526KB) ( )  
    Related Articles | Metrics
    Ablocked disaccharide portion of the biological repeat unit, [→4) α-D-Glcp (1→3)-α-L-Rhap (AcO→2) (1→] of the Serratia marcescens O4 oligosaccharide wasprepared by using 1-O-trlfluoroacetoxy, trlchloroacetoxy or trichloroacetimido as leaving groupof sugar in the presence of Lewis acid. The reaction conditions were very mild, and theyields were also good. Trlfluoroacetoxy and trlchloroacetoxy are good leaving groups and af-ford the products in a high stereoselectivity. All compounds were confirmed by IR, MS, Hand 13C NMRspectral methods.
    Synthesis, Properties of Asymmetric Carbocyanine Dyes and Squarylium Cyanine Dyes Containing Benzotellurazoles
    LUO Xue-Hong, LIU Xiu-Fang, XU Han-Sheng
    1997, 18(9):  1474-1478. 
    Asbtract ( )   PDF (484KB) ( )  
    Related Articles | Metrics
    Starting from benzotellurazolium iodldes, four asymmetric carbocyanlne dyescontaining tellurium were synthesized by refluxing with 3-ethy1-2-(β-acetylanilide) vinylbenzothiazolium iodlde in dry pyridine. Aconvenient procedure for synthesis of asymmetricsquarylium cyanlnes has been developed. The particular reactiveness betweenbenzotellurazolium iodide and squarlc acid was found. Only 1:1 condensation is Involved in thisreaction, and the resultant can condense easily with benzothiazolium lodide to give asymmetricsquarylium dye of tlnique component without separation. The "Brooker deviation" of theasymmetric telluracarbocyanines was also discussed.
    Ester-Containing Polymer Encapsulated PackingMaterial for Liquid Chromatography
    ZUO Yu-Min, ZHANG Kun, LU Wen-Shuo, XU Xiao-Wen, PANG Zhi-Long, QI Jing-Xian
    1997, 18(9):  1479-1483. 
    Asbtract ( )   PDF (458KB) ( )  
    Related Articles | Metrics
    Aseries of ester-containing polymer encapsulated packing material for reversedphase high performance liquid chromatography was prepared by radical polymerization ofmethyl or octyl acrylate and divinylbenzene with vinyl-bonded silica in solution. The polymerlayer was characterized by FTIR, SEMand elemental analysis. Some characteristics such asresidual silanols, column pressure, column efficiency and peak asymmetry were evaluated.The polymer encapsulated packing materials are inorganic packings with organic coatings,thus combining the favorable mechanical properties of silica nuclei with the favorablechemical stability of polymer coatings. The plots of lgk' of solute against methanol content of amobile phase using the packing material. In the case of aniline, benzene, and o-nitrophenol,the plots have a linearity similar to those of reversed phase packings. These packings weresuitable for separation of amino-and hydroxyl groups containing compounds because of thestability and the absence of acidic silanol groups. At the same time, they will play animportant role in rapid separations of complex mixtures because the mass transfer to the stationaryphase is fast. Its superior performance for the analysis of Lovastatin is demonstrated asapplication example.
    Studies on the Mg2+-Catalyzed Reductions of N-Arylfluorenimines by NAD(P)H Models
    LU Yun, XIAN Ming, CHENG Jin-Pei
    1997, 18(9):  1484-1487. 
    Asbtract ( )   PDF (329KB) ( )  
    Related Articles | Metrics
    The reductions of N-arylfluorenlmines by Hantzsch ester in the presence andabsence of Mg2+ have been studied. The similar reductions by BNAHhave been compared.The results show that (1) Mg2+ plays a role of electrophilic catalyst; (2) the strongerreduction ability of Hantzsch ester than BNAH Is the result of electrostatic effect caused by its3,5-carbonyl oxygens which decreases the energy of the transition state more effectively;(3) one-step hydride transfer mechanism has been proposed.
    Synthesis, Optical Absorption and Xerographic Properties of Bisazo Pigments from 2,7-Diaminofluorenone
    ZHANG Yu-Hong, ZHU Long-Guan, CAI Guo-Qiang, MA Lin, YU Qing-Sen
    1997, 18(9):  1488-1490. 
    Asbtract ( )   PDF (309KB) ( )  
    Related Articles | Metrics
    Several bisazo pigments were synthesized by coupling 2, 7-diaminoflurenone with avariety of 2-hydroxy-3-naphthanilides. The results of elementary analysis and iRindicatedthat the synthesis and purification were successful. The UVspectra of the pigments in DMFrevealed that the visible absorption bands of Azo-3 and Azo-4 were red-shifted obviouslywhich can be attributed to the significant conjugate effect. When the pigments in DMFwereirradiated using an infrared lamp, the properties of photochrism were observed. When theirradiation was carried out by using a high pressure mercury lamp, the absorption of thesolutions was decreased. The xerographic performence of Azo-3 in combination with two chargetransport molecules [ 4-(diethylamino) benzaldehyde diphenyl-hydrozone (DEH) and4(dimethylamino) benzaldehyde phenylnaphthylhydrozone (DENH)] was investigated. Wefound Azo-3 has a better photosensitivity by using DENHas charge transport molecule andpoly(methyl methacrylate) (PMMA) as charge blocking layer.
    In situ FTIR Spectroscopic Investigations of Abnormal Infrared Properties of Absorption of CO and SCN- on Dispersed Pt and Pd Surfaces
    LU Guo-Qiang, SUN Shi-Gang, CHEN Sheng-Pei, CAI Li-Rong, LI Nan-Ha, TIAN Zhao-Wu
    1997, 18(9):  1491-1495. 
    Asbtract ( )   PDF (406KB) ( )  
    Related Articles | Metrics
    The in situ molecular-probe FTIRspectroscopy was employed in the present workto study the adsorption of CO and SCN- on surfaces of dispersed Pt and Pd thin layers,which were deposited electrochemically on glassy carbon (denoted as Pt/GCand Pd/GC)uner voltanmmetric conditions. Abnormal IRfeatures of adsorption of COand SCN- andPt/GCand Pd/GChave been observed for the first time. In comparison with IRfeatures ofadsorption of these molecules on smooth Pt and Pd electrodes, the abnormal IRfeaturesconsist of mainly the inversion of the direction of IRband and the enhancement of bandintensities. The enhancement factors were evaluated at 20 for linearly bonded COon the Pt/GCsurface anal at 26 for bridge bonded CO on the Pd/GCsurface. Nevertheless other spectralfeatures(the vibrational frequency, the Stark effects, etc.) are nearly the same as thoseobserved on smooth Pt and Pd electrodes, and no significant difference in IRfeatures presentedfor adsorption of solution species (CO2, SCN-) on the dispersed surfaces. The surfaceroughness of these dispersed electrodes was measured relatively small (1.6 for Pt/GCand 1.2for Pd/GC). The present study discovered an interesting IRproperty of dispersed metallicthin layers, and suggested that the in situ iRspectra of larger signal to noise ration may beobtained by employing the specially prepared Pt/GCand Pd/GCelectrodes.
    Theoretical Studies of Nonlinear Second-Order Optical Properties of a Series of Molecules of Benzoquinone Derivatives
    FENG Ji-Kang, REN Ai-Min, LI Zhi-Ru, SUN Chia-Chung
    1997, 18(9):  1496-1501. 
    Asbtract ( )   PDF (436KB) ( )  
    Related Articles | Metrics
    On the bases of AM1 and ZINDOmeth0ds, according to the sumover-states ex-pression, the nonlinear second-order optical susceptibilities βijk of a series of molecules ofbenzoquinone derivatives have been calculated. Systematic theoretical studies on the nonlin-ear optical second-order properties of benzoquinone series molecules have been performed, i.e. on the base of R'C6H4NHC6O2NH2Rindependently changing Rand R', the rule of varia-tions of β has been examined. The regularity summarized from calculated results has beenexplained micromechanica1ly.
    Factors Influencing the Formation of Plating Zn-Ni Alloy and Its Reaction Mechanism
    WU Chen, LI Dong-Feng, WANG Jian-Gang
    1997, 18(9):  1502-1505. 
    Asbtract ( )   PDF (369KB) ( )  
    Related Articles | Metrics
    Recently great progress has been made on the research on plating Zn-Ni alloy.However, research on the factors influencing its formation is still insufficient. Experimentsto investigate all factors inf1uencing its formation were conducted in our research and the fac-tors influencing the composition and properties of the plating layer were reported in this pa-per. Arigorous reaction mechanism was proposed,
    Ab Initio Study of the Reaction of Alkaline Earth Atom on Ground State Ba(1S) with ClO2
    HUANG Jian-Hua, YE Song, DAI Shu-Shan
    1997, 18(9):  1506-1510. 
    Asbtract ( )   PDF (354KB) ( )  
    Related Articles | Metrics
    The reaction of alkaline earth atom Ba (1S) on ground state with ClO2 has beenstudied using ab i,lItio MOmethod. Two different channels on doublet potential energy sur-face have been discussed and compared. The results show that channel (1), through whichchlorizate was generated, is favorable in energy. The dominant products are BaCl and O2,which are in agreement with the experimental results. Moreover, the formation of productswith a low excited state has also been discussed.
    Kinetic Studies for State-State Transition of SO2(X1A1,A1A2, B1B1) System Excited by266 nm Laser
    ZHANG Qun, ZHANG Hua, CHEN Cong-Xiang, YU Shu-Qin, MA Xing-Xiao
    1997, 18(9):  1511-1516. 
    Asbtract ( )   PDF (501KB) ( )  
    Related Articles | Metrics
    The dispersed fluorescence spectrum of SO2 (B1B1→X1A1. 320~380 nm) excitedby 266 nm laser lnto the first allowed absorptlon reglon (240~340 nm) where the high vibrational levels of A1A2 an B1B1 states are strongly coupled, and its preliminary assignment arepresented. Athree-level model ls proposed to deal with the SO2 (X1A1, A1A2, B1B1) systern,and the coup1ing coefficlent, ξ, and the relaxation time, τ, at tlie high vibratlonal levels ofA1A2 and B1B1 states have been obtalned. The results show that ξ and τ keep basically constant under our exl)erimental conditions, which reflects the cI1aracteristics of the system.
    The Structure-Function Relationship of Core Complexes in Phycobilisome(Ⅱ) ──Studies on Chromophore-Chromophore Interactions in Four Allophycocyanin Complexes
    WANG Hui, ZHAO Jing-Quan, YANG Zi-Xuan, ZHANG Jian-Ping, JIANG Li-Jin
    1997, 18(9):  1517-1522. 
    Asbtract ( )   PDF (466KB) ( )  
    Related Articles | Metrics
    Four forms of allophycocyanin (APC) complexes with different structures andspectral properties in trinleric as well as monomeric aggregates were isolated from phycobili-some and characterized by both absorption and fluorescence spectra. The interactions be-tween chromophores of these APCcomplexes and their functlons in energy transfer processwere studied by deconvolutlon of absorption spectra. The results indicate that the interactionbetween chromophores of allophycocyanin complexes could be explained by Forster dipoledipole resonance Tnechanism, and it was linker polypeptides and homologous chromophoresthat influence the structural symmetry which flnally affects the interaction mechanism ofchromop hores.
    Chemical Reactions of Laser Ablated Ti Atom with Halomethanes in Gas Phase
    LIANG Bin-Yong, ZHANG Yong, GU Zhen-Ning, QIN Qi-Zong
    1997, 18(9):  1523-1526. 
    Asbtract ( )   PDF (306KB) ( )  
    Related Articles | Metrics
    The gas-phase reactions between laser ablated Ti atom and four different kinds ofhalomethane (CF4, CF3Br, CF3Cl, CCl4) were studied by a home-made tlme-of-fIight massspectrometer (TOF-MS) coupled wlth a pulse molecular beam device. Apulsed laser beam at532 nm was employec1 to ablate a tltanlum target and generate the metal Ti atoms, whichwill react with a pulsed supersonic molecular beam of halomethane using Ar as a carrier gas.The neutral products were detected by laser nonresonance photoionization with 266 nm pho-tons and timech-of-flight (TOF) mass spectrometry. The measured TOFmass spectra showthat only TiFis formed in the reactions of Ti atom with CF4, CF3Br and CF3Cl, while TiCl isformed in the reaction of Ti atom with CCl4. Our results can be explained in terms of an elec-tron transfer mechanism via an ion-pair complex, such as:Ti+CF3X→[Ti+2X] → TiF + CF2X
    Effects of Cationic Surfactant Cetylpyridine Bromide Micelle upon the Hydrolysis of 2,4-Dinitrochlorobenzene
    SHEN Ji-Jing, ZHAO Zhen Guo, MA Ji-Ming
    1997, 18(9):  1527-1529. 
    Asbtract ( )   PDF (2313KB) ( )  
    Related Articles | Metrics
    The Ieaction between hydroxide ion and 2, 4-dinitrochlorobenzene in water wascatalyzed by cationic micelles of cetylpyridine bromide (CPB). The rate constant first increased sharply. then remained relatively constant as the concentration of CPBincreased.The kinetic form can be interpreted quantatively in terms of incorporation of substrate andhydroxide ion into the eationic micelles. Increasing the hydroxide ion concentration decreasedthe second-order rate constant of the micellar-catalyzed hydrolysis. The rate enhancement ismore pronounced in CPBthan in cetyltrinlethylammonium1 bromide system. The difference ofthe effects of the two cationic micelles has also been discussed.
    Catalysis of Copper-containing Transition Metal Hydrotalcitelike Compounds in the Phenol Hydroxylation with Hydrogen Peroxide
    ZHU Kai-Zheng, LIU Chi-Biao, YE Xing-Kai, WU Yue
    1997, 18(9):  1530-1533. 
    Asbtract ( )   PDF (268KB) ( )  
    Related Articles | Metrics
    Hydrotalcite-like compounds containing carbonate ion as the interlayer anion wereprepared by coprecipitation under low supersaturation condition by mixing an aqueous solu-tion of metal nitrates with an aqueous solutions of NaOHand Na2CO3 at room temperature,maintaining pH =8-10 with vigorous stirring- Following the mixing, the resulting heavyslurry was aged at 353 Kfor 18 h with vigorous stirring, The precipitate was then filtered,washed several times with hot distilled water and dried in air at 353 Kovernight. In thisway, CuM1 AlCO3-HTLcs and M1 AlCO3-HTLcs were synthesized and characterized bymeans of XRDand lR. The catalysis of the above mentioned HTLcs were investigated in thephenol hydroxylatlon with H2O2. The results indicated that all of the copper-containingHTLcs had a higher catalytic activity in the reaction. However, those catalysts that did notcontaln copper had no catalytlc actlvlty in this reaction- This means that copper was the ac-tive center in the phenol hydroxylation. Meanwhile, the mechanism was also proposed,which could be used to explain the main reason for higher activity for CuCuAlCO3-HTLcs inthe phenol hydroxylation and the effect of Mg2+, Zn2+, Co2+, Ni2+ on activlty of CuM1 Al-CO3-HTLcs.
    Studies on the Formation of Charge Transfer Complex Between Fullerene and Zinc Phthalocyanine
    CHEN Zai-Hong, XIE Yong-Ming, LI Juan, ZHAN Meng-Xiong
    1997, 18(9):  1534-1536. 
    Asbtract ( )   PDF (242KB) ( )  
    Related Articles | Metrics
    The system of ZnPc-C60 ln speclal mixed organic solvents has been studled by UVVis, fluorescence and laser Raman spectra. The results prove the existence of a chargetransfer complex (CTC) by the lnteractlon between ZnPc and C60 The molar ratio of ZnPc/C60 in CTCis 2: 1. The formation equilibrium constant(K) was determined at 25 C. Mea-surements of photovoltaic effect show that ZnPc-C60 CTCleads to a rernarkable enhancementof photosensitivity comparing to that of ZnPc.
    The Bulk Free Radical Copolymerization of Styrene and Maleic Anhydride
    DONG Yu-Ping, FENG Lin-Xian, YANG Shi-Lin, SHEN Jia-Cong
    1997, 18(9):  1537-1540. 
    Asbtract ( )   PDF (386KB) ( )  
    Related Articles | Metrics
    The comPosition of copolymer depended on the concentration of initiator in thebulk free radical polymerization of styrene (St) and maleic anhydride (MA) at 7O ℃. In Iowconcentration of initiator the cornposition of copolymer had nothing to do with the content ofmonomer in the feed. However, in high concentration of initiator the product of polymeriza-tion contained polystyrene and random copolymer. Homopolymerization of styrene took placewhen copolymerization stopped at lower conversion. At the sarne time, copolymer tended to1: 1 alternation with the increasing of content of MAin the feed in the range of 70-160℃.The experimental results indicated that the two sorts of polymerization simultaneously exist-ed if temperature was over 12O℃. The conversion of copolymerization had less dependenceon the temperature and were less than 50%. The composition of copolymers tended to 1: 1alternation as the temperature approached 140℃. The random copolymers of St and MAwere yielded above 140 ℃.
    Morphologies and Mechanical Properties of Epoxy Resins Toughened by Hydroxyl-terminated Butadiene-acrylonitrile Copolymer
    LI Shao-Ying, HAN Xiao-Zu, ZHANG Qing-Yu
    1997, 18(9):  1541-1545. 
    Asbtract ( )   PDF (507KB) ( )  
    Related Articles | Metrics
    The morphologies and mechanical properties of epoxy resins toughened by hy-droxyl-terminated butadiene-acrylonitrile copolymer (HTBN) and cured with hexahydroph-thalic anhydride were studled. The results show that the level of HTBNin epoxy resin, con-tent of acrylonitri1e in HTBNand curing temperature influence the morphology and then in-fluence the mechanical properties of cured epoxy resin.
    Microemulsion Polymerization of Styrene Initiated with Potassium Persulfate
    XU Xiang-Ling, ZHANG Zhi-Cheng, ZHANG Man-Wei, GE Xue-Wu, WU Zhi-Chao
    1997, 18(9):  1546-1550. 
    Asbtract ( )   PDF (519KB) ( )  
    Related Articles | Metrics
    The monomer content and the ratlo of monomer to emulsifier in styrene mi-croemulsion were greatly uplifted when it was stabllized with an emulsifier with Ystructure.The microemulsion was polyrnerized in dilatometer with potassium persulfate as an initiator.The change of polymerization rate with conversion was recorded, and the plateau of polymer-ization rate in microemulsion polymerization of styrene was first observed. The Iength of theplateau was shortened with the increase of KPSconcentration and emulsifier concentration,or with the decrease of monomer concentration. The polymerlzation kinetics and the poly-merization mechanisms were also discussed.
    Rheological Properties of PET/PA66/Liquid Crystalline Copolyesteramide Blends
    XIE Xiao-Lin, SHEN TU Bao-Qing, LI Bo-Geng, PAN Zu-Ren, WU Da-Cheng
    1997, 18(9):  1551-1555. 
    Asbtract ( )   PDF (509KB) ( )  
    Related Articles | Metrics
    The blends of poly(ethylene terephthalate) (PET), polyamlde 66 (PA66) andliquid crystalline copolyesteramide (LC30) were prepared by mechanical mixing. Theirmorphology and rheological properties were investigated by means of SEM, cross polarizingoptical microscope with hot-stage and Instron3211 type capillary rheometer. The results showthat PET/PA66/LC30 is an incompatible multiphase blending system in thermo dynamics.The compatibility and rheological properties of PET/PA66 blends are greatly improved byadding LC30. The viscosity curves of PET/PA66/LC30 melts consist of two regions: a shearthinning region at low shear rate and a"pseudo Newtonian" region. PET/PA66/LC30 blendsshow the character of the positive deviation blends (PDB), whereas PET/PA66 blends showthe character of the negative deviation blends (NDB). The rheological properties of theseblends are affected by their morphologlcal structure.
    Synthesis of Phosphatidyl Ethanolamine Polyphosphate Liposomal Materials
    LIU Zhen-Hua, CHEN Mao, FAN Chang-Lie, ZHANG Jie, ZHUO Ren-Xi
    1997, 18(9):  1556-1559. 
    Asbtract ( )   PDF (320KB) ( )  
    Related Articles | Metrics
    Four phosphatidyl ethanolamine polyphosphates were prepared by polycondensation of β-chloroethyl dichlorophosphate and pentaerythritol di-fatty acid esters in benzene,and then by aminatlon with ammonia. Liposomes were prepared with these amphiphilicpolymers according to REVmethod. All materials could form large unilamellar vesicles (LUV)detected by polarized optical microscope and electron microscope. Encapsulation efficienciesof liposome (Ⅱa-Ⅱd) to 5-fluorouracil and release rate of liposome were determined.
    Effect of Secondary Doping on Properties of the Conductive Composites of Polyaniline
    MA Yong Mei, WANG Xiang-Yang, GUO Jun-Shi, XIE Hong-Quan
    1997, 18(9):  1560-1564. 
    Asbtract ( )   PDF (424KB) ( )  
    Related Articles | Metrics
    The conductivity of composite, which was prepared by in situ emulsionpolymerization technique, shows different percolation thresholds: 21. 0% for PAn/CSPEand 7. 0%for PAn/SBScomposites cast from solution. It Increases two orders of magnitude andexhibits a new percolation threshold 3. 0% for two kinds of composites after secondary dopingwith mucresol. The secondary doping noticeably increases permanent set change withpolyaniline content. The SEMimage of broken section shows that the secondary dopingchanges the ductile fracture Into the brittle fracture. The results show that the secondarydoping induced a tenuous interconnected network through expanded polyaniline backbone.Secondary doping had no marked effect on tensile strength and elongation, which Indicatesthat the tenuous Interconnected network of the conductive component had no contribution forstress-transfer. Electrochromic performance of composite film was also studied in neutral oracidic electrolyte.
    The Characterization of Polymer Microspheres Composited with Fe2O3 in Nano-Scale
    DU Hui, LIU Zhi-Qiang, LIU Feng-Qi, LI Tie-Jin, TANG Xin-Yi, XU Wei-Qing, WU Ying
    1997, 18(9):  1565-1567. 
    Asbtract ( )   PDF (280KB) ( )  
    Related Articles | Metrics
    Fe2O3 nanoparticles with diameter 3-5 um were encapsulated in polymer latexparticles. The size of the composite microspheres was 80 um. From IRspectra, the changesof absorption band on carbonyl groups indicated the strong interaction between Fe2O3 and thesurface groups of seed latex particles. According to Mdssbauer spectra, we were sure aboutthe core-shell structure of the inlayer microspheres from the changes of the electron densityand symmetry of the chemical environment around Fe2O3.
    Analysis of the Waterborne Particles of Bisphenol A Type Epoxy Resin
    YANG Zhen-Zhong, ZHAO De-Lu, XU Mao, XU Yuan-Ze
    1997, 18(9):  1568-1570. 
    Asbtract ( )   PDF (387KB) ( )  
    Related Articles | Metrics
    The waterborne particles of bisphenol Aepoxy resin were prepared by the phaseinversion technique, and the effects of the concentration of the synthetic polymeric emulslfleron the particles size and structure were discussed. At lower concentration of the emulsifier,the bigger molecular sieves alike particles were obtained, on the contrary, the smallerparticles with some aggregation were prepared at higher concentration of the emulslfler. Theformation mechanism of different particle sizes and structure at different concentrations of theemulsifier was proposed. presides, the probable model of the aggregation was also brieflypresented.
Special Issues
More...
Download
More...
Links
More...