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Table of Content

    24 March 1999, Volume 20 Issue 3
    Articles
    A Study of Conformation Equilibrium and Interaction of Porphyrin Dimers
    REN Qi-Zhi, HUANG Jin-Wang, LIN Cui-Wu, JI Liang-Nian
    1999, 20(3):  333-338. 
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    Aseries of porphyrin dimers and their zinc complex covalently linked with _O(CH2)-nO_ chain were synthesized and characterized. Their steady state fluorescence spectra show the existence of intramolecular energy transfer processes in these free base porphyrin dimers. C4free dimer has the greatest efficiency of energy transfer. By using IR and 1HNMR methods, the relationship between the conformation equilibrium and the length of the alkoxyl chain, the metal complexation was studied. With the increase of the length of the chain, the conformation equilibrium of porphyrin dimers moves to the closed conformation, the chain length of C4dimer was suitable to form the closed conformation. The metallation with zinc ion increases the magnitude of π-π interaction of two porphyrin rings while it does not affect the conformation equilibrium of porphyrin dimers.
    The Synthesis and Structure of Al2Mo3-xWxO12
    ZHAO Xin-Hua
    1999, 20(3):  339-343. 
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    The title compounds were synthesized and characterized as P21/a space group in monoclinic phase for x=0, 0.5, 1.0, 1.5, 2.0 and Pbcn space group in orthohombic phase for x=2.5, 3.0. The structure refinments were success for x=0, 0.5, 1.0, 1.5, 2.0 using laboratory Xray data. The preliminary interpretation of the phase transition was discussed on the basis of the structural parameters.
    Synthesis, Characterization and Catalysis Acitivity of the MCM-48 Framework Containing Ti, Co, Cr, Mn, Cu, Mo
    CAI Qiang, WEI Chang-Ping, XU Yong-Yi, PANG Wen-Qin, ZHEN Kai-Ji
    1999, 20(3):  344-349. 
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    In this paper, the MCM-48 framework containing Ti, Co, Zr, Cr, Mn, Cu and Mo was synthesized and characterized by means of HRTEM, pore diameter distribution, XRD, XPS and IR absorption spectra. In addition, we also studied their catalysis behavior for the conversion from eicosanol to eicosanic acid. The experimental results show that the Ti, Cr, Zr doped MCM-48 pocesses excellent catalysis properties.
    Syntheses and Properties for Strontiumphthalocyanine and Its Sulfonated Derivative
    GUO Zhong-Ping, WU Ming-Guang, ZHAN Meng-Xiong
    1999, 20(3):  350-352. 
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    Strontiumphthalocyanine and its sulfonated derivative were synthesized. The structures of products were characterized by means of IR, UV-V is spectra and elementary analysis. The constituents of strontiumphthalocyanine and sulfonated strontiumphthalocyanine were identified as SrPc and SrPcSx(Pc=C32N8H16, S=SO3, x=2~3), respectively. Besides, the solubility and photoelectric properties of the products were determined.
    New Method for Distinguishing GeometricaLIsomers of Tri-substituted Keggin-type Heteropolyanions α-and β-[SiW9M3(H2O)3O39]7-(M=Al3+, Ga3+)
    HUANG Ru-Dan, QIAO Zheng-Ping, LI Bai-Tao, FEI Bao-Li, WANG En-Bo
    1999, 20(3):  353-355. 
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    The tri-substituted heteropolyanions with Keggin structure, α-and β-, are two important geometricaLIsomers. They have promising utilizations in catalysis, high protonic conductors and anti-vitus. The phase transformation method has been used to investigate the different microcosmic crystals, when tri-substituted Keggin-type heteropolyanions are dissolved in the organic solvent of benzene. The different microcosmic crystals are taken as the new method to distinguish geometricaLIsomers of tri-substituted Keggin-type heteropolyanions. This work has filled up the gaps of microcosmic crystals in doing research work containing heteropolyanions in organic solvent.
    A Novel MCM-41-β-zeolite Composite Molecular Sieve with Mesoporous and Microporous Structure
    GUO Wan-Ping, HUANG Li-Min, CHEN Hai-Ying, LI Quan-Zhi
    1999, 20(3):  356-358. 
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    MCM-41-β-zeolite, a new type of molecular sieve with meso-microporous composite structure was synthesized hydrothermally by using cetyltrimethylammonium bromide and tetraethylammonium hydroxide as the template. The structure and property of the molecular sieve were studied by means of XRD, SEM, DTG, FTIRand probe reaction teachniques. The results show that the composite molecular sieve contains stable hexagonal mesoporous structure and the microporous structure of β-zeolite. It appears in globular particles with loose surface and the results of DTG and FTIR exhibit that the meso-microporous composite molecular sieve is different from the mechanical mixture of MCM-41 and β-zeolites. Compared with the mechanical mixture of MCM-41 and β-zeolites, MCM-41-β-zeolite has a much higher hydrocracking activity for n-heptane.
    Hydrothermal Synthesis and Characterization of BiFeO3
    SHI Yan-Hui, FENG Shou-Hua, LI Ji-Xue, ZHANG Rui-Chang, LI Wan-Feng
    1999, 20(3):  359-360. 
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    The compound BiFeO3was synthesized in alkaline medium with BiONO3(or BiCl3) and Fe(NO3)39H2O as the reactant at 120-40 for 1-3d. The product was characterized by powder X-ray diffraction, thermogravimetric and differential thermal analyses and IR spectroscopy. The compound crystallizes in a rhombohedral system with cell parameters a=0.3956 nm, α=89.43.
    Studies on the Diffusion-controlled Solid-solid State Reaction by Means of XRD
    ZHOU Yi-Ming, YE Xiang-Rong, LI Dao-Hua, XIN Xin-Quan
    1999, 20(3):  361-363. 
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    Solid-solid state condensation reaction of p-hydroxybezaldehyde and p-chloroaniline was conducted at low-heating temperature. The reaction product was proved to be the corresponding Schiff base. TG-DTA and XRD measurements were performed to investigate the solid-solid state reaction process. It is fairly definite that the reaction is diffusion-controlled.
    Factor Analysis Used to Peak Position Optimization and SpectraLINterference Correction in Inductively Coupled Plasma Atomic Emission Spectrometry
    LIU Si-Dong, GUO Li-Ping, ZHANG Zhuo-Yong, CHEN Hang-Ting, ZENG Xian-Jin
    1999, 20(3):  364-368. 
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    Target transformation factor analysis was used to correct spectraLINterference in inductively coupled plasma atomic emission spectrometry(ICPAES) for the determination of rare earth impurities in high purity thulium oxide. Data matrix was constructed with pure and mixture vectors and background vector. Amethod based on an error evaluation function was proposed to optimize the peak position, so the influence of the peak position shift in spectral scans on the determination was eliminated or reduced. Satisfactory results were obtained using factor analysis and the proposed peak position optimization method.
    Studies on the Determination of Superoxide Anion Radical(O2) and Superoxide Dismudase(SOD) Activity by Flowinjection Spectrophotometry
    DU Ming, LIANG Fang-Zhen, TANG Bo, SHEN Han-Xi
    1999, 20(3):  369-373. 
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    Four thiocarbohydrazones of 1,5-bis(salicylidene)thiocarbohydrazone(BSTZ), 1,5-bis(phydroxybenzaldene)thiocarbohydrazone (BHBTZ), 1,5-bis(mmethoxyphydroxybenzaldene)thiocarbohydrazone(BMHBTZ) and 1,5-bis(mmethoxysalicylidene)thiocarbohydrazone(BMSTZ) were synthesized. BHBTZ and BMHBTZ can be oxidated by superoxide anion radical(O2) and H2O2.Based on the reaction, the determination of O2by flow injection spectrophotometry was developed. The linear range of O2concentration is from 4.5×10-7mol/Lto 1.5×10-6mol/L. The detection limit is 1.5×10-7mol/L. The relative standard deviation is 5.23%. Coexist substances in many biological samples have no interference. The method can also be used to determine the activity of superoxide dismudase(SOD).
    Synthesis of the New Reagent of p-Dimethylaminochlorophosphonazo and Its Coloration Reaction with Thorium(Ⅳ)
    HUANG Ya-Li, LIU Shao-Pu
    1999, 20(3):  374-377. 
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    The synthesis of the new reagent p-dimethylaminochlorophosphonazo(CPApDMA) and its colour reaction with thorium(Ⅳ) were studied. In HCl medium, the reagent reacted with thorium(Ⅳ) to form a blue complex with n[Th(Ⅳ)]:n[CPApDMA]=12 and an apparent molar absorptivity of 9.86×104L·mol-1·cm-1at 674 nm. The accumulating method of absorbances at multiwavelength for determining thorium(Ⅳ) was based on the sum of absorbances for the complex at 674, 612 and 538 nm, the apparent molar absorptivity in this case was 1.74×105L·mol-1·cm-1. Beers law is obeyed for thorium(Ⅳ) in the range of 0~30 g/25 mL. Most of the coexistent ions did not interfere with the determination of Th(Ⅳ). The method has been applied to the determination of trace amounts of thorium in rock standard samples with a high sensitivity and selectivity.
    Studies on Adaptive Filtering of AnalyticaLINstrument Signal Based on Wavelet Theory
    DONG Yan-Shi, CHENG Yi-Yu
    1999, 20(3):  378-382. 
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    In this paper, a new type of adaptive filtering algorithm, which can adaptively remove all kinds of noises from signals of analyticaLINstruments under a variety of complex conditions, is proposed. At present, the popular filtering algorithms which are widely applied to the data processing equipment for analyticaLINstrument are lowpass filter or bandpass filter. The fundamental of those filters depends on the fact that the frequency characteristics of real signals are different from those of noises. These filtering algorithms based on the different frequency distribution characteristics between signals and noises have an obvious defect, that is, users have to preset properly initial filter factors according to the width of peaks, which greatly influences the objectivity and veracity of computational results in analytical procedures. In the light of the wavelet transform modulus maximum theory proposed by Mallat, the characteristics of wavelet transform modulus maxima of real signals are distinctively different from those of noises in the practical signals of analyticaLINstruments, such as chromatography. It is easy to identify them. Taking advantage of the different characteristics between real signals and noises on different scales in wavelet transformation domain, noises can be removed from the practical signals of analyticaLINstruments while avoiding to distort the real signals. The adaptive filtering algorithm designed by this principle breaches the popular patterns of current filtering algorithms, and radically improves the filtering effects. Alot of tests using chromatography data prove that this algorithm has a serial of virtues, such as no requirement on artificially presetting filter factors, excellent separation of signals and noises, holding the position and height of peaks, and so on. Its performance in the robustness, adaptability and fidelity of peak completely satisfy the needs of signal processing for analyticaLINstruments.
    Wavelet Smoothing and Denoising to Process Capillary Electrophoresis Signals
    WANG Li-Shi, YANG Xiao-Yun, XI Shao-Feng, MO Jin-Yuan
    1999, 20(3):  383-386. 
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    In this work, the results of wavelet smoothing and wavelet denoising to process capillary electrophoresis(CE) signals show that in processing CE signals, using wavelet smoothing the signal peaks are broadened and shortened, and using wavelet denoising, the peaks are well described.
    A New Mathematical Model for Investigating the Sampling Errors of Twocomponent Particulate Mixtures
    GAO Zhi, HE Xi-Wen, ZHANG Gui-Zhu
    1999, 20(3):  387-391. 
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    Anew mathematical model was established for investigating the sampling of twocomponent particulate mixtures by mass. By the introduction of a new concept named as logical unit of sampling by mass, equations of estimating the standard deviation and relative standard deviation of sampling by mass were presented. The physical meaning of the logical unit of sampling by mass was also studied. These equations were verified by the sampling for chemical analysis of twocomponent medicine tablets. This theory is generally applicable so as to enrich the sampling theory of analytical chemistry and direct the sampling practices.
    Sensing Characteristics of Thicknessshearmode Acoustic Wave Sensor Modified with Plasmadeposited n-Butylamine Film
    XIANG Jian-Nan, YIN Xia, CAO Zhong, WANG Ke-Min, LIN Hui-Gai, YU Ru-Qin
    1999, 20(3):  392-394. 
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    Anbutylamine plasma coated thicknessshearmode(TSM) acoustic wave sensor was prepared on the surface of quartz crystal using a plasma deposited technique. The response characteristics of the TSM sensor for a series of organic vapors were reported. It shows that the TSM can be used for sensing carboxylic acid vapor efficiently and possesses considerably long lifetime compared with the sensor coated by common chemical polymer. The sensor possessed good reproducibility, high stability and rapid response time to formic acid while coating with 96.40 g of plasmadeposited nbutylamine. Compared with acidbase titration method, the sensor can be .used for the determination of HCOOH sample with recovery rate of 96.6% to 104.2%.
    Syntheses and Biological Activities of 2-Arylamidothioacyl-3-isothiozolones and 4-Cyano-5-methylthio-2-arylamidothioacyl-3-isothiozolones
    YANG Xiao-Ping, LI Zheng-Ming, CHEN Han-Song, LIU Jie, LI Shu-Zheng
    1999, 20(3):  395-398. 
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    Novel compounds, 2-arylamidothioacyl-3-isothiozolones 6 and 4-cyano5-methylthio-2-arylamidothioacyl-3-isothiozolones 7 were synthesized by reacting of 3-hydroxyisothiozoles(4, 5) with aryLIsothiocyanates 3 . The unique coupling constants of 4-H and 5-H of isothiazole ring of compounds 6 were discovered and explained according to the coplanarity of isothiazole ring with thioacyl group. The preliminary test of fungicidal activity showed that some of the title compounds possessed promising activity.
    Structure and Bioactivities of Lacguer Polysaccharides from Chinese Lac Trees of Wild Species and Cultispecies
    DU Yu-Min, YANG Jian-Hong, KONG Zhen-Wu, XIAO Ling
    1999, 20(3):  399-402. 
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    Two lacguer polysaccharides(LP) were isolated and purified from sap of Damu(wild species) and Xiaomu(cultispecies) lac trees in Hubei Province of China, and were analyzed by using chemical degradation, FTIR, GC, GCMS, 1HNMR and HPGPC. The results indicated that two LP were all composed of β(1→3)D-Gal main chain with the branches having (16) linked glucuronic acid, arabinose and rhamnose. Differently, the LPfrom Damu contain branches linked with (14) and higher branching factor than that of Xiaomu. The molecular weight (Mw) was obtained to be 10.7104 and 12.5104 by HPGPC, respectively. The results obtained by intra perctoncaLINjection in mice showed that DLP and XLP have immunostimulant activities, and the DLP from Damu has a significantly higher bioactivity in motivating the growth of leucocytes than that of Xiaomu. It is regarded that the decrease in the molecular weight could lead to an enhancement of bioactivities of the DLP from Chinese lac tree of wild species.
    Synthesis and Spectroscopic Characterizations of Polyfluoroalkoxy Chlorophthalocyanines
    SI Yu-Gui, GONG Yue-Fa, ZHANG Zheng-Bo
    1999, 20(3):  403-406. 
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    The preparation of some chlorophthalocyanines and the reactions of them with sodium polyfluoroalkoxide were reported in this paper. Some polyfluoroalkoxy chlorophthalocyanines have been obtained by this way, and characterized by elementary analysis, IR, UV-Vis, 19FNMR spectra after purification. The effects of introduction of polyfluoroalkoxy group in the ring on the solubility, thermodynamic stability and electronic spectra were also discussed.
    Synthesized and Biological Activity of Chlorosubstituted Propenol Prethreid
    WEI Yun-Ting, HUANG Run-Qiu, BI Fu-Chun
    1999, 20(3):  407-410. 
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    Twenty new compounds were synthesized by acylation reaction of chlorosubsti-tuted propenol with 3(2,2dichlorovinyl)2,2-dimethylcyclopropane carbonyl chloride, 3(2,2-dimethylvinyl)2,2-dimethylcycloprepane carbonyl chloride and 2(4-chlorobenzenyl)2isopropyl carbonyl chloride. Their structures were confirmed by means of elemetal analysis and 1HNMR; the preliminary biological tests show that the knock down activities(KT50) against mosquito of the compounds 6 (3.9 min) and 15 (4.2 min) are higher than the compared insecticide methothrin(KT505.7 min and 4.8 min respectively), and the title compounds , when Y=H, have better insecticidal activities than which Y=CN.
    Synthesis and HilLINhibitory Activity of Ethyl 2-Cyano-3-methylthio-3-arylaminoacrylates
    LIU Hua-Yin, LU Rong-Jian, CHEN Kai, TAN Hui-Fen, YANG Hua-Zheng
    1999, 20(3):  411-414. 
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    Based on our previous studies, the title compounds were designed and synthesized, all compounds have been confirmed by 1HNMR and elemental analysis. The HilLINhibitory activity of all titlecompounds were tested, and the bioassay results indicate that some of themshow a good inhibitory activity, the relationship between the structure andinhibitory activity was analyzed.
    The Improved Synthesis of Queen Bee Pheromones
    ZHU Hong-You, LIN Jun, HE Hong-Ping, LIU Fu-Chu
    1999, 20(3):  415-417. 
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    In this paper, we described the synthesis of the main bioactive components of queen bee pheromones, queen substance 9-oxo-2E-decenoic acid (1) and stink-odour inhibitor 9-hydroxy-2E-decenoic acid (2) from natural oleic acid. The key intermediate 9-heptadecene-2-one (5) was obtained by PdCl2(PPh3)2catalytic decarboxylation of oleic acid and followed by Wacker oxidation. The synthesis of the trace components, 4-hydroxy-3-methoxyphenylethanol (3), is also reported.
    A Facile Onestep Synthesis of 1-Acylindolizines by the Reaction of Pyridinium Salts with Mannich Bases in the Presence of TPCD
    WANG Bing-Xiang, HU Jia-Xin, HU Yue-Fei, HU Hong-Wen
    1999, 20(3):  418-420. 
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    Afacile onestep method is presented for the synthesis of 1acylindolizines in moderate yields by the reaction of pyridinium salts with Mannich bases in the presence of NaHCO3and a mild oxidizing agent, tetrakispyridine cobalt dichromate (TPCD).
    BaeyerVilliger Oxidation of 4-Bromo-5-methylisatin
    CHEN Wei-Min, ZENG Long-Mei
    1999, 20(3):  421-423. 
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    Two different products were obtained while 4-bromo-5-methylisatin was oxidized by separately using organic peroxy acids and Caros acid as the oxidizing agent. The chemical structures of the oxidation products were elucidated by spectra analysis to be a pair of isomer: novel compound 5-bromo-6-methyl-1H-benzo oxazine-2,3-dione and the known compound 5-bromo-6-methyl-1-Hbenzo oxazine-2,4-dione. The product is free of isomer for each reaction. The reaction mechanisms were also discussed.
    Studies on Microstructure of Dodecylbetaine System with 1HNMR and Raman Method
    LI Ying, LI Gan-Zuo, HAO Shu-Xuan, LI Li-Xia
    1999, 20(3):  424-427. 
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    1HNMR spectroscopy was used to study the microstructure of dodecylbetaine/phenylcarbinol/water system and determine the position of phenylcarbinol molecule in the micell. It was found that there was another kind of transitional structure beside W/O and O/W type in the system. According to the results of 1HNMR and Raman study it should be a long-range ordered structure called pseudo liquid crystal. Analyzing the 1HNMR spectra of the system the range of the three types of micell was given: W/O, pseudo liquid crystal, O/W. In pseudo liquid crystal system, the molecules were highly orderized.
    Theoretical Study on Stochastic Resonance in Pt(100)/NO+CO System
    ZHOU Bao-Jing, YANG Ling-Fa, XIN Hou-Wen
    1999, 20(3):  428-431. 
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    The Pt(100)/NO+CO system exhibits complex kinetic phenomena such as chemical oscillation and multisteady state when located far from the equilibrium. Applying the mathematical model suggested by Fink, we add periodic and stochastic perturbations on carbon monoxide partial pressure in computer simulation. The result shows stochastic resonance(SR) phenomena existing in two different regions. One is the traditional bistable region, the other is the coexistence of the oscillation with the stable state. Acontrast between SR phenomena in the two regions demonstrates that the two coexisting states vary considerably in their stability.
    Theoretical Study on the Addition Reaction Mechanisms of C60
    SHANG Zhen-Feng, PAN Yin-Ming, WANG Hai-Xiang, ZHAO Xue-Zhuang, TANG Ao-Qing
    1999, 20(3):  432-435. 
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    Detailed AM1 calculation is reported for the reaction mechanism of C60with o-quinodimethanes. The geometries of products and transition states have been optimized. The result show that the reaction of C60with o-quinodimethanes has a concerted mechanism. Frontier orbital theory was used to study the reactivity of dienes and it was found that the reaction was controlled by the LUMO of C60.
    Ab initio Study of Silver Sulfur Binary [Ag·(Ag2S)n]+(n=1,2) Clusters
    CUI Meng, FENG Ji-Kang, GE Mao-Fa, WANG Su-Fan, SUN Chia-Chung, GAO Zhen, KONG Fan-Ao
    1999, 20(3):  436-439. 
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    The possible geometrical structures of [Ag·(Ag2S)n]+(n=1,2) cluster were optimized by using the methods of ab initio Molecular Orbital Restrict Hatree-Fock(RHF) and Density Function Theory(DFT). The corresponding stable geometries and electronic structures were obtained. That the two clusters can act as the deep trap of free electron of sulfur sensitive center was also explained.
    Monte Carlo Simulation of CO Desorption from Fe(100)
    FU Gang, XIA Wen-Sheng, WAN Hui-Lin, ZHANG Qian-Er
    1999, 20(3):  440-444. 
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    On the basis of bridgelike model, temperatureprogrammed desorption(TPD) spectrum for CO parallel adsorption on Fe(100) surfaces is simulated by Monte Carlo method, which is combined with bondorder conservation Morse potential(BOCMP) approach. The surface reaction process and metaladsorbate(MA) and adsorbateadsorbate(AA) interactions were considered in this simulation. The results are agreement with those observed experimentally. In addition, the effect of CO dissociation and desorption on TPD spectra is also discussed.
    Periodic and Aperiodic Oscillation of Cyclic Voltammetric Responses of Oxidition of Alcohol at Platinized Platinum Electrode in Alkaline Medium with Na2MoO4
    FU Hong-Gang, YU Hai-Tao, WANG Jun-Dong, CHEN Xu, XU Shan-Peng, HUANG Ju-Ying
    1999, 20(3):  445-449. 
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    Avariety of nonlinear phenomena, which was observed during the electrochemical oxidation of ethanol and methanol at a platinized platinum electrode, is described. The cyclic voltammetric responses of ethanol and methanol that are oxidized at a platinized platinum working electrode in alkaline medium with Na2MoO4show the periodic and aperiodic cyclic voltammetric oscillatory behavior. The periodic and aperiodic cyclic voltammetric oscillatory responses were obtained under given experiment conditions. The period of oscillation can be controlled by changing little low potential limit. The alkalinity has an important effect on the oscillation. The periodic oscillations appear when the concentration of ethanol vary between 0.5 mol/Land 1.0 mol/Land the solution contain Na2MoO4. Without Na2MoO4in the solution, the oscillation doesnt appear in such an alkalinity. The periodic and aperiodic oscillation have the properties of chaos. We consider that the nonlinear behavior is the surface.
    A Theoretical Study on the Electrophilic Activities of Squaraines
    YANG Ming-Li, SUN Ze-Min, YAN Guo-Sen
    1999, 20(3):  450-453. 
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    On the basis of AM1 method, the interactions between the squaraines and the anions, such as F-, Cl-, Br-, O2-, S2-, etc., have been studied by means of the proposed modeLIN which the anion approaches vertically the center of the four-membered rings of the squaraine. The calculated results suggest that the squaraines are characterized by the particular electron-defect rings and tend to act upon the electron-rich anions. The strength of these action is related to the charges and polarizabilities of the anions and is improved by the introduction of electron with drawing groups.
    Effect of Different Surfactants on the Behavior of AgCl Nanoparticles in Reversed Micelles
    ZHANG Zhi-Ying, WANG Chuan-Yi, LIU Chun-Yan
    1999, 20(3):  454-457. 
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    The effects of surfactants with different charges on the interaction of eosin(EO) and AgCl nanoparticles in reversed micelles have been studied. The effects of AgCl nanoparticles on the absorption and fluorescence spectra and the fluorescence lifetime of eosin in reversed micelles have been observed. The influence of PMT and TAIon the interaction was also discussed.
    Theoretical Studies on the Structure and Vibrational Spectrum of N@C60
    GE Mao-Fa, FENG Ji-Kang, CUI Meng, TIAN Wei-Quan REN Ai-Min, SUN Xiu-Yun, SUN Chia-Chung
    1999, 20(3):  458-460. 
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    The geometry of N@C60 was optimized by using ab initio Unrestricted Hartree-Fock method. The results show that nitrogen is in the center of the cage in the form of atom basically, but there are some interactions between nitrogen atom and carbon cage. That is in agreement with the experimental results. We further calculated the vibrational spectrum of N@C60 and compared it with C60.
    A Study of Mechanism of Modified TiO2Photocatalysts for Photoreduction of CO2 with Surface Photovoltage Spectrum
    XU Yong-Jun, XIE Teng-Feng, WANG De-Jun, WANG Ying, LI Tie-Jin
    1999, 20(3):  461-463. 
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    The study of mechanism of modified TiO2photocatalysts for photoreduction of CO2with surface photovoltage spectrum(SPS) was reported for the first time. The results showed that a new surface photovoltaic response band appears in the SPS curve of Pd/TiO2or Pd/RuO2/TiO2in near IRregion, moreover, the stronger SPS response intensity in near IRis, the higher the catalytic activities of photoreduction of CO2.The surface state plays a role in the process of photocatalysis.
    SnCl4Catalysed Oxidation of Acetone with Hydrogen Peroxide to Macrocyclo Peroxide
    JIANG Heng, LI Hai-Ying, HAN Xiao-Xiang, QIAO Qing-Dong
    1999, 20(3):  464-466. 
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    SnCl4·5H2Oand SnCl2·2H2O are the efficient catalysts for the oxidation of acetone with 30% hydrogen peroxide at room temperature to tetrametric acetone peroxide which is identified by molecular determination, elemental analysis, FT-IR, NMR, and MS. The catalytic activity of SnCl4·5H2O and SnCl2·2H2O is much higher than that of HCl. In the case of SnCl4·5H2O, the maximum yield of tetrametric acetone peroxide reaches 95.0%. The results show that the active species of catalytic reaction may be Sn4+.
    Preparation of Ultrafine Rutile Titania Crystals by Liquid Method
    ZHAO Jing-Zhe, WANG Zi-Chen, LIU Yan-Hua, WANG Li-Wei, SONG Qing, YANG Hua, ZHAO Mu-Yu, FENG Shou-Hua, XU Ru-Ren
    1999, 20(3):  467-469. 
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    Rutile titania crystals were directly prepared in liquid system without anatase-to-rutile transformation, while Ti(SO4)2and ammonia are the raw materials. The process of preparation can be divided into two parts: one is precipitating, the other is peptizing. The conditions of precipitating influence the structure of the resulted crystals, even though Ti(OH)4precipitates obtained during precipitating are amorphous. Peptizing is the process of the formation of crystals, the amorphous Ti(OH)4precipitates changing into titania with the change of rutile structure.
    Studies on Phase Structure of Polyurethanes Prepared from Poly(1,3-dioxepane) Diols --Effect of Chemical Structure of Soft Segment on Phase Structure of Polyurethanes
    LIU Ye, YANG Bo, ZHOU Xian-Zhi, PAN Cai-Yuan
    1999, 20(3):  470-473. 
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    Polyurethanes were prepared using poly(1,3-dioxepane)diols(polyDOP) and poly(tetrahydrofuran)diols(polyTHF) as soft segment. The phase structures of these polyurethanes were analyzed by means of FTIR and DSC methods. The introduction of oxymethyl groups into the main chain of poly(THF) resulted in lower crystallization abilities of soft segment phase and heterogeneity of order region in hard segment phase. The effects of the chemical structure of soft segment on the crystallization of soft segment phase and order region in hard segment phase were discussed.
    Influence of Molecular Weight of Chitosanon Liquid Crystalline Behavior
    WANG Jian-Wei, DONG Yan-Ming, LIU Huang-Nan, YUAN Qing, MEI Xue-Feng
    1999, 20(3):  474-477. 
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    The lyotropic cholesteic liquid crystalline phase was observed in the dichloroacetic acid solutions of the three chitosans with different molecular weights from 2.34106 to 0.44106 but with the same degree of deacetylation. The critical concentration of chitosan decreased when its molecular weight increased and was higher than chitin with the same degree of polymerization. The value of average pitch obtained by both small angle light scattering and polarized microscopy decreased when the molecular weight of chitosan increased.
    Development in Microemulsion Polymerization
    XU Xiang-Ling, YIN Ya-Dong, GE Xue-Wu, YE Qiang, ZHANG Zhi-Cheng
    1999, 20(3):  478-485. 
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    The difference between microemulsion and emulsion polymerization was summarized on polymerization mechanism, polymer properties. The new development of microemulsion polymerization was also introduced.
    Conformation Transformation of Syndiotactic Polypropylene Induced by Stretching and Annealing
    ZHANG Bin, YANG De-Cai
    1999, 20(3):  486-488. 
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    Conformation transformation of syndiotactic polypropylene(sPP) induced by stretching and annealing processes has been investigated by WAXD, IRand DSC. The results indicate that not only the quenched samples but also the isothermally crystallized samples can form the crystals with alltrans conformation by means of uniaxially stretching at room temperature. The alltrans conformation crystals are of metastability, which can transform to stable crystals with (TTGG)2helical conformation at higher annealing temperatures.
    Synthesis of Rigid Long Sidechain Liquid Crystalline Polymers with Intermolecular Hydrogen Bonds
    XIE Xiao-Lin, LI Bo-Geng, PAN Zu-Ren
    1999, 20(3):  489-491. 
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    Rigid long sidechain liquid crystalline polymers with intermolecular hydrogen bonds were synthesized with random styrenmaleic anhydride copolymer(RSMA) and phydrobenzoic acid(HBA) by catalyzing and insitu acetylation. Their chemical structures were characterized by FTIR spectrum. Polarizing microscope with hotstage and DSC were applied to investigate the liquid crystallinity. It was found that RSMA-g-HBA copolymers contain intermolecular hydrogen bonds and exhibit nematic mesophase.
    Studies on Synthesis of Graft Copolymers with p-Chloromethyl-styrene Copolymers as Macroinitiators
    ZHANG Yong-Ming, LUO Ning, YING Sheng-Kang
    1999, 20(3):  492-494. 
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    Aseries of graft copolymers were synthesized by ATRP initiated with macroinitiators which had been made from copolymerization of p-chloromethylstyrene and other monomers, such as methyl methacrylate, butyl methacrylate, acrylonitrile, styrene, vinyl acetate, isobutene-maleic anhydride, styrene-maleic anhydride etc.. The graft copolymers were characterized by IRand 1HNMR spectra. The numbers of graft points or the branches on the graft copolymers were determined by Ion Chromatography. The design for the various structures and architectures of the graft copolymers was made by changing the compositions of the backbones and the branches. The results indicated that it is a versatile route to synthesize a lot of graft copolymers and will be commercially important in the future.
    Surface Activity of the PAMAM Dendrimer Aqueous Solutions
    LONG Fei, FAN Yu, DING Hui-Jun, JIA Xin-Ru, LI Ming-Qian
    1999, 20(3):  495-497. 
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    The generations of 0.5, 1.5, 2.5, 3.5, 4.5 of the PAMAM dendrimers and 1, 2, 3, 4 of the PAMAM dendrimers have been synthesized with an EDA core. Surface tensions of the dendrimer aqueous solution have been measured by drop-volume method. It is showed that (1) the dendrimer aqueous solutions have a surface activity and the order of the surface activity is G=4.5>G=3.5>G=2.5>G=1.5>G=0.5; (2) the plateau area of G=4.5 is more obvious than those of G=3.5 and G=2.5, the reason is not clear now; (3) as compared with G=0.5, 1.5, 2.5, 3.5, 4.5 of dendrimer, the cationic ones containing ——C12H25had a higher surface activity.