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    24 October 2004, Volume 20 Issue 5
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    Articles
    Synthesis and Spectroscopic Characterization of Organothiophosphoryl Polyoxotungstates α-[C6H11P(S)]2Xn+W11O39(8-n)- (Xn+=P5+, Si4+, Ge4+, Ga3+)
    SUN Zhen-gang, YOU Wan-sheng, ZHU Zai-ming, GU Yuan-peng, LIU Jing-fu
    2004, 20(5):  517-520. 
    Abstract ( )   PDF (208KB) ( )  
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    Organothiophosphoryl polyoxotungstate derivatives α-C6H11P(S)]2Xn+W11O39(8-n)- (X=P, Si, Ge, Ga)were obtained by the reactions of the monovacant α-[Xn+W11O39](12-n)- (X=P, Si, Ge, Ga) anions with electrophilic C6H11P(S)Cl2 in acetonitrile.These new organic-inorganic hybrid anions were characterized by elemental analyses, IR, 31P and 183W NMR spectrometries.The six-line 183W NMR spectrum indicates that [C6H11P(S)]2Xn+W11O39(8-n)- (X= P, Si, Ge, Ga) anions possess true Cs symmetry in acetonitrile.According to the spectroscopic observation and the chemical analyses, it is known that each of the hybrid anions consists of an α-[XW11O3)] framework on which two equivalent C6H11P(S) groups are grafted through P-O-W bridges.
    Preparation of α-Fe2O3 Nanofiber via Electrospinning Process
    SHAO Chang-lu, YANG Xing-hua, GUAN Hong-yu, YU Na, LIU Yi-chun
    2004, 20(5):  521-522. 
    Abstract ( )   PDF (147KB) ( )  
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    A thin PVA/FeCl3 composite fiber was prepared by using sol-gel processing and electrospinning tech niques.A nanofiber of α-Fe2O3 with the diameter of 50_150 nm was obtained via high temperature calcina tion of the PVA/FeCl3 composite fiber.The material was characterized by infra-red(IR) spectroscopy, X-ray diffraction(XRD), and scanning electron microscopy(SEM).The results show that the fiber after the calci nation at 700 ℃ was a pure α-Fe2O3 nanofiber.
    Change Color Effect and Spectral Properties of Gold Nanoparticle-cationic Surfactants System
    JIANG Zhi-liang, PAN Hong-cheng, YUAN Wei-en
    2004, 20(5):  523-528. 
    Abstract ( )   PDF (292KB) ( )  
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    The change color effect of gold nanoparticle solutions was studied by means of resonance scattering and absorption spectrometry and scan electron microscopy.The red Au nanoparticles with a size of 10 nm exhibit a resonance absorption peak and a resonance scattering peak all at 525 nm.After some inorganic electrolyte was added to a red Au nanoparticles solution, the color of the solution became blue and the absorbance at 600_700 nm was significantly increased.The ratio of the concentration of monovalent cations, at which the resonance scattering of the system at 525 nm is maximal to that of divalent cations, is in the range of 100 : 1 _100 : 1.8.It is in good agreement with the Schulze-Hardy rule of the coagulation value of electrolyte.After adding some cationic surfactants to the above solution, the color of the solution is in deep blue, with two resonance absorption peaks at 550 and 680 nm, and a greatly enhanced resonance scattering peak at 525 nm.The experiments demonstrate that the stronger the hydrophobicity of the cationic surfactant is, the stronger the change color effect of the Au nanoparticle solution promoted by cationic surfactant is.The change color effect of Au nanoparticle solution is resulted from the increased diameter of Au nanoparticles, and the changes of resonance absorption peak and resonance scattering.
    Electrocatalytic Oxidation and Ion Chromatography Detection of S2O32-, SO32-, I- and SCN- at Glassy Carbon Electrode with Functionalized Multi-Wall Carbon Nanotubes Film
    XU Ji-ming, WANG Yan-ping, XIAN Yue-zhong, JIN Li-tong
    2004, 20(5):  529-533. 
    Abstract ( )   PDF (263KB) ( )  
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    In this research, a glassy carbon electrode modified with the functionalized multi-wall carbon nanotubes (MWNT-COOHs) film was used as an amperometric sensor for the determination of S2O32-, SO32-, I- and SCN-.The electrochemical behavior of those oxidizable inorganic anions at this modified electrode was studied by means of cyclic voltammetry(CV).The experimental results indicate that the modified electrode exhibits a high electrocatalytic activity towards the oxidation of those anions with a relatively high sensitivity, a good stability and a long-life.Separated by ion chromatography(IC) with 1.25 mmol/L H2SO4 as an eluent,those oxidizable anions can be determined by the MWNT-COOHs modified electrode successfully.Under the optimal chromatographic conditions, the detection limits are 1.5 × 10-7 mol/L for S2O32-, 2.5 × 10-7 mol/L for SO32-, 1.2 × 10-7 mol/L for I- and 2.0 × 10-7 mol/L for SCN-, respectively.The method was applied successfully to the determination of those anions in environmental water.
    Determination of Heroin Based on Analyte Pulse Perturbation to an Oscillating Chemical Reaction
    REN Jie, GAO Jin-zhang, Suo-nan, ZHAO Guo-hu, YANG Wu, LÜ Dong-yu, SUN Kan-jun, LI Chong-yang
    2004, 20(5):  534-538. 
    Abstract ( )   PDF (264KB) ( )  
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    A new analytical method is proposed for the determination of heroin based on a sequential perturbation caused by trace amounts of heroin in the Cu (Ⅱ)-catalyzed oscillating reaction between hydrogen peroxide and sodium thiocyanate in an alkaline medium with the aid of a continuous-flow stirred tank reactor (CSTR).The method relies on the linear relationship between the change in oscillation period of the system and the concentration of heroin, with a detecting limit of 4.0× 10-7 mol/L.The calibration curve fits a linear equation very well when the concentration of heroin is in the range of 2.0 × 10-6_ 1.2 × 10-5 mol/L (r = 0.9971).This method features good precision(RSD= 0.98%).The influences of temperature, injection point, flow rate and reaction variables on the oscillation period were investigated in detail and a possible mechanism of the performance of heroin in the Cu( Ⅱ )-catalyzed oscillating reaction system is also discussed.The proposed method opens a new avenue for the determination of heroin.
    Screen and Capacity of Predominant Strain for Toluene Biodegradation in Groundwater
    ZHANG Lan-ying, LIN Xue-yu, Taboure Aboubacar, LIU Rui, ZHANG Yu-ling
    2004, 20(5):  539-542. 
    Abstract ( )   PDF (218KB) ( )  
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    The soil nearby a gas station was collected, from which we isolated a series of strains by means of enrichment and screening technigues.The most effective strain for the degradation of toluene, i.e., JYZ0315 was screened by the further mutation of the above strains.The degradation capacity experiment was carried out in simulated groundwater.Under the optimal conditions, the degradation rate could reach 93.5%.During the extend application experiments with a percolation tank, the degradation of toluene reached 87.3% in 11 d and 95.2% in 15 d, which was close to that of the microenvironment, and this proves that JYZ0315 is one of the predominant strains to degrade toluene in groundwater.
    Syntheses of 1,3,4-Thia(oxa)diazole-substituted Pyrazole Derivatives and Their Fungicidal Activities
    WANG Wen-yan, ZHAO Wei-guang, LI Zheng-ming
    2004, 20(5):  543-547. 
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    A series of 1,3,4-oxadiazole or 1,3,4-thiadiazole-substituted pyrazole derivatives were synthesized from 4-pyrazole formhydrazide; their biological activities were studied.The structures of all the new compounds were confirmed by means of spectroscopic methods and mieroanalyses.The preliminary bioassay results indicate that some compounds of them have a good fungicidal activity against Phoma asparagi and Physalospora piricola Nose.
    Syntheses, Characterization and Crystal Structures of Two-dimensional 4,4'-Bipyridyl Lead Halides,PbI2 (4,4'-bpy) and PbBr2 (4,4'-bpy)
    YIN Han-dong, CUI Ji-chun
    2004, 20(5):  548-550. 
    Abstract ( )   PDF (1270KB) ( )  
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    Two-dimensional 4,4-bipyridyllead halides, PbI2 (4,4'-bpy) (1) and PbBr2 (4,4'-bpy) (2), were synthesized.The structures were determined by means of X-ray single crystal diffraction.The structure shows a distorted octahedral configuration with six-coordinated central lead atoms.In crystals 1 and 2, the molecules are packed in a two-dimensional network structure through bridging halide atoms and 4,4'-bipyridine ligands between the adjacent lead atoms.
    Syntheses and Bioactivity of 4"-Sulfonate-5-triphenylsilyl Avermectin B1a and Ivermectin B1a Derivatives
    LIAO Lian-an, FANG Hong-yun, LI Zheng-ming, ZHAO Wei-guang, FAN Zhi-jin
    2004, 20(5):  551-557. 
    Abstract ( )   PDF (330KB) ( )  
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    Fourteen new derivatives of avermectin B1a and ivermectin B1a were synthesized from C5-O-triphenylsilyl avermectin B1aand ivermectin B1a(yield from 40% to 83%).Their chemical structures were characterized by means of IR, 1H NMR, 13C NMR and FAB-MS spectrometries.Some of them show excellent insecticidal activity.
    Synthesis and Structure Characterization of Novel Triazole Compounds Containing 1,3-Dioxolane
    XU Liang-zhong, JIAN Fang-fang, NIU Shu-yan, JIANG Zhi-guo
    2004, 20(5):  558-561. 
    Abstract ( )   PDF (218KB) ( )  
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    Five novel triazole compounds containing group 1,3-dioxolane were designed and synthesized by taking difenoconazole as the start compound and changing diphenyl ether for benzyl phenyl ether.Their structures were confirmed by elemental analyses, 1H NMR and IR spectra.The single crystal structure of 2-[4-(2,4-dichlorophenylmethoxy]phenyl-2- (1,2,4-triazol-1-yl) methane-1, 3-dioxolane was determined by means of X-ray diffraction.The preliminary bioassays showed that the synthesized compounds exhibited some activities of fungicides and plant growth regulators.
    X-ray Structure of Bis(salicylidene)-p-diaminobenzene
    ZHANG Shu-sheng, YE Su-juan, ZHANG Tong, LI Xue-mei
    2004, 20(5):  562-564. 
    Abstract ( )   PDF (714KB) ( )  
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    The crystal and molecular structures of Schiff base bis (salicylidene)-p-diaminobenzene were determined by X-ray crystallography.It crystallized in a monoclinic system with space group P2 (1)/c, lattice parameters a=1.4649(3) nm, b=0.45770(9) nm, c=1.2241(2) nm, α=γ=90.00°, β=112.07 (3)°, V=0.7606(3) nm3, and Z=4.The crystal structure of the title compound is composed of discrete monomeric molecule of (C6HD (NCC6H4OH)2 which is planar.The intermolecular hydrogen bonds make the compound steady.
    Synthesis and Crystal Structure of Novel Dimer of Bismuth( Ⅲ ) Complex with Dithiotetrahydropyrrolocarbamate: [Bi(S2CNC4H8)2 (NO3)]2
    YIN Han-dong, WANG Chuan-hua, MA Chun-lin
    2004, 20(5):  565-567. 
    Abstract ( )   PDF (577KB) ( )  
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    A novel dimer of the bismuth ( Ⅲ ) complex with dithiotetrahydropyrroloearbamate, [Bi(S2CNC4H8)2 ·(NO3)]2, was synthesized and the crystal structure was determined by X-ray single crystal diffraction.The crystal belongs to a monoclinic system with space group P21/n, a=0.64718(13) nm, b=2.6738(6) nm, c=1.0423(2) nm, β=106.384(3)°, Z=4, V=1.730(3) nm3, Dc=2.163 g/cm3, μ=10.682 mm-1, F(000)=1072, R= 0.0329, wR=0.0659.The structure shows a distorted pentagonal bipyramidal configuration with the seven-coordinated central Bi atom.In the crystal, the molecular packing in the unit cell reveals that the two adjacent molecules are symmetrically linked each other in the dimer by virtue of a couple of Bi-S interaction.
    Synthesis of Cyclic Carbonates from CO2 and Epoxides Catalyzed by Hexaalkylguanidinium Halides
    DUAN Hai-feng, LI Sheng-hai, LIN Ying-jie, XIE Hai-bo, ZHANG Suo-bo, WANG Zong-mu
    2004, 20(5):  568-571. 
    Abstract ( )   PDF (563KB) ( )  
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    Hexaalkylguanidinium halides exhibit an efficient catalytic activity in the synthesis of cyclic carbonates from epoxides and carbon dioxide.By this method cyclic carbonates can be obtained in a high yield and a high selectivity at a low temperature and atmospheric pressure.This procedure is easy for the product isolation and recycling of the catalyst.
    A Global Minimization Algorithm for Empirical Contact Potential Functions
    WANG Yu-hong, LI Wei
    2004, 20(5):  572-574. 
    Abstract ( )   PDF (1481KB) ( )  
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    Global minimization algorithm is indispensable to solving the protein folding problem based upon thermodynamic hypothesis.Here we propose a pseudo potential function, contact difference (CD), for simulating empirical contact potential functions and testing global minimization algorithm.The present paper covers conformational sampling and global minimization algorithm called BML03, based upon Monte Carlo and simulated annealing, which is able to locate CD's global minimum and refold extended protein structures into ones with root mean square distance(RMSD) as small as 0.03 nm from the native structures.For empirical contact potential functions, these results demonstrate that their global minimization problems may be solvable.
    Resolution of 2-Octanol via Lipase-catalyzed Enantioselective Acetylation in Organic Solvents
    WANG Zhi, LI Zheng-qiang, Yu Da-hai, WENG Liang, LIU Ming, ZHANG Gui-rong, CAO Shu-gui
    2004, 20(5):  575-578. 
    Abstract ( )   PDF (692KB) ( )  
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    The lipases from different sources were screened for their ability to catalyze the resolution of 2-octanol in organic solvents with vinyl acetate as the acylating reagent.The medium effect has been studied on the irreversible transesterification with varying water activity(aw).The influence of vinyl acetate concentration on it has also been investigated.Under the optimal conditions, the enantiomeric ratio(E value) of pseudomonas fluorescence lipase(PFL) exceeded 200 with an enantiomeric excess(e.e.) of S-2-octanol above 99% at a 51% degree of conversion.
    Preparative Purification and Bioassay of Bt Toxin from Cry1Ab Transgenic Rice
    WU Jian-min, YE Qin-fu
    2004, 20(5):  579-583. 
    Abstract ( )   PDF (716KB) ( )  
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    A method of extracting and purifying Cry1Ab protein(Bt toxin) from Cry1Ab transgenic rice was established.Most of the Bt toxin present in the tissue of Cry1Ab transgenic rice was extracted effectively with a solution of 50 mmol/LNa2CO3 and NaHCO3.The crude protein containing Bt toxin was obtained after the pretreatment of Cry1Ab transgenic rice with ultra-filtration, ammonium sulfate precipitation and centrifugation.The dialysed crude protein was futher separated on DEAE Sephadex A-50 columns and Sephadex G-150 columns.The protein bound on DEAE Sephadex A-50 gel was eluted with buffer solution B(10 mmol/L trisHCl buffer+1.0 mmol/L EDTA, pH=8.0) mixed with 0.1, 0.3, 0.5 and 0.8 mol/L NaCl in a discontinuous gradient elution mode.The peak of the Bt toxin eluted from the columns was identified by ELISA and bioassayed with larvae of tobacco hornworms and silkworms.The purity and the bioactivity of the Bt toxin were determined by means of SDS-PAGE and larvicidal assay, respectively.The purity of the Bt toxin obtained by this method is high, and its insecticidal activity is retained after the toxin is purified.
    Solid-phase Synthesis of Acyl-plasminogen-Streptokinase Activator Composite(APSAC) and Its Thrombolytic Properties
    TENG Li-rong, LIANG Fang, SUN Hong, QIN Yi, HONG Shui-sheng, CHEN Jia, LIU Lan-ying
    2004, 20(5):  584-587. 
    Abstract ( )   PDF (731KB) ( )  
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    The dialysis method has been traditionally used for the conversion of native human plasminogen (GluHpg) to lys-plasminogen(Lys-Hpg).Here is described a solid-phase synthesis method for the preparation of an acyl-plasminogen-streptokinase activator complex(APSAC) from Lys-Hpg, streptokinase (SK) and chemical modification agent(4-amidinophenyl-4'-aminobenzoate hydrochloride) with the L-lysine-Sepharose 4B Column as the carrier.The new method significantly increases the product yield and purity over the liquidphase methods.The APSAC prepared with the new method exhibits a significant thrombolytic effect with a long half-life of about 8.8 h in rabbits.
    Purification and Characterization of Cyclic AMP-Binding Protein from Ganoderma lucidum
    WANG Qi, KIM Jung-Sik, CHUNG Ki-Chul
    2004, 20(5):  588-593. 
    Abstract ( )   PDF (817KB) ( )  
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    Cyclic AMP-binding protein was purified 30 fold from the mycelia of Ganoderma lucidum by the methods of ammonium sulfate precipitation, DEAE-cellulose, phospho-cellulose ion exchange chromatography and Sephacryl S-100 gel filtration.The molecular mass of the purified protein is 34.5 kDa and 17 kDa by Sephacryl S-100 gel filtration and SDS-ployacrylamide gel electrophoresis, respectively.From these results it is suggested that the protein has a homometric dimmer structure.The pI of the purified protein is pH 8.2 by native isoelectric focusing gel.The half-life of the protein activity in 10% glycerol at 4 ℃ is 7 d in crude extract, but its half-life is only 3 d under purifying conditions.The optimal conditions of the protein activity are at 1 ℃ and pH 7.5.Its activity is increased 6 times by 1 mmol/L Zn2+ and is slightly inhibited by cGMP,Cu2+ and Mn2+.
    Kinetic Studies on Interactions of Ferreous-porphyrins with Hydrogen Peroxide
    YAN Yan, JIAN Wen-ping, GUO Hong-wei, YANG Ke-er, Tong Shan-ling, FANG Chi-guang, LI Qing, CHANG Xin, XIAO Feng-shou
    2004, 20(5):  594-597. 
    Abstract ( )   PDF (1013KB) ( )  
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    In an alkali-methanol solution, both 1- and 2-naphthol can be converted into 2-hydroxy-1,4-naphthoquinone (HNQ) with selectivity more than 95% by H2O2 over metalloporphyrin catalyst.The UV-Vis spectra indicate that a high valence oxygen-ferreous porphyrin intermediate has been produced by addition of an aqueous solution of H2O2 into the catalytic system.This intermediate formation rate is influenced by the concentrations of low valence ferrous porphyrin, H2O2, and NaOH existing in the system.With the aid of the UVVis spectrum varieties, the rate equations and formation rate constants of the intermediate at different temperatures can be determined by changing the original concentration of each reactant.The formation activation energy of this intermediate was also determined by changing temperature.
    Ultrasonic-enhanced Stereoselective Debromination of vic-Dibromides to Alkenes with Metallic Zinc Powder in Aqueous Media
    LI Pin-hua, RAO Wan-ping, WANG Min, WANG Lei
    2004, 20(5):  598-601. 
    Abstract ( )   PDF (730KB) ( )  
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    Carbon-carbon double bond functional groups are often protected through a popular bromination/debromination method because of their reactivity.An ultrasonic-enhanced stereoselective debromination of vicdibromides with metallic zinc powder in aqueous media has been developed, which generates E-alkenes with excellent yields.The reactivity of vic-dibromides decreases in the order of 1,2-dibromo-1,2-diphenylethane＞1,2-dibromo- 1-phenylethane ＞ 1,2-dibromo-1,2-dialkylethane.
    Intermolecular Interaction of HMX: an Application of ONIOM Methodology
    JU Xue-hai, BEI Feng-li, XIA Qi-ying, XIAO He-ming
    2004, 20(5):  602-605. 
    Abstract ( )   PDF (2021KB) ( )  
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    Ab initio calculations at the B3LYP/3-21G**, HF/3-21G＞** and ONIOM(HF/3-21G** : AM1) levels of the theory in combination with counterpoise procedure for BSSE correction were performed on HMX dimers.There exist two O…H intermolecular contacts and the dispersion forces are dominant in the dimers.The corrected binding energies of the dimer are -15.10 and -17.81 kJ/mol at the HF/3-21G** and ONIOM(HF/3-21G**: AM1)levels, respectively.The calculation by the B3LYP method gives irrational corrected binding energies though it produces similar intermolecular distances as those produced by the HF or ONIOM method.The geometrical parameters, the contact distances and the binding energies demonstrated,for the first time, the validity of the ONIOM method applied in the calculation of the parameters of intermolecular interactions.
    Effects of Hydrogen-bonding Interaction and Polarity on Emission Spectrum of Naphthalene-Triethylamine in Mixed Solvent
    XIE Guo-bin, Yoshimi Sueishi, Shunzo Yamamoto
    2004, 20(5):  606-611. 
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    The effects of the protic and aprotic polar solvents on the emission spectrum of the naphthalene-triethylamine system in THF were studied under conditions of steady-state illumination.The fluorescence spectrum of the naphthalene-triethylamine system consists of two emission bands, the fluorescence band of naphthalene (band A, 329 nm) and the emission band of the exciplex(band B, 468 nm).The intensities of both the emission bands decrease with increasing the solvent polarity.The intensity of band B also decreases due to the hydrogen-bonding interaction between triethylamine and protic solvent, while that of band A increases.It is thus suggested that the quenching of naphthalene fluorescence by triethylamine in THF occurs through the charge transfer and electron transfer reactions.The spectral changes upon the increase of solvent polarity can be explained by the dependences of the equilibrium constant between exciplex and ion-pair and the rate constant for the electron transfer reaction from triethylamine to the excited naphthalene on the relative permittivity of solvent.It is shown that the formation of intermolecular hydrogen-bonding between triethylamine and protic solvent suppresses the quenching reaction by the decrease in free amine.Acetonitrile has only a polar effect and trichloroacetic acid only a hydrogen-bonding(or protonation) effect, while alcohols have both the effects.The effects of alcohols could be separated into the effects of solvent polarity and intermolecular hydrogen-bonding interaction quantitatively.
    Thermodynamic Analysis and Experimental Investigation into Nonflame Combustion Technology(NFCT) with Thermal Cyclic Carrier
    HE Fang, WANG Hua, DAI Yong-nian
    2004, 20(5):  612-616. 
    Abstract ( )   PDF (715KB) ( )  
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    The utilization of fossil fuels causes serious negative impacts on the environment and human life.To mitigate greenhouse gases and other pollutants, a novel combustion process-the nonflame combustion technology with a thermal cyclic carrier of molten salt is introduced.In this technology, a whole combustion is divided into two steps, i.e., the section of producing oxide and the section of combustion.In the first step, oxygen is separated from air, and pure N2 is simultaneously formed which is easily recovered.In the other step, the fuels react with lattice oxygen in the oxides formed in the first step, and at the same time, thermal energy,CO2 and H2O vapor are produced.It is noted that the CO2 is easily separated from water vapor and ultimately captured.Theoretically, there are no environmental-unfriendly gases such as CO2, NOx and SO2 discharged in the whole combustion process.Some metal oxides scattered into molten salts play the roles of oxygen carriers in the combustion system, and they can constantly charge and discharge oxygen element from air to fuels during the combustion process.A nonflame combustion system with Li2CO3+K2CO3+Na2SO4 as the molten salt system, CH4 as the fuel and CuO as the catalyst was experimentally investigated.The experimental results show that the combustion process proceeded as it was theoretically analyzed, and CO2 with a high volume fraction of 77.0%_95.0% and N2 with a high volume fraction of 91.9%_99.3% were obtained.The high concentration of CO2 is favorable for capturing and storing subsequently.Therefore, the potential of reducing CO2 emissions of this nonflame combustion technology is huge.
    Enhanced Capacitive Characteristics of Activated Carbon by Secondary Activation
    YANG Hui, LU Tian-hong, Yoshio Masaki
    2004, 20(5):  617-623. 
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    The effect of the improvement of commercial activated carbon(AC) on its specific capacitance and high rate capability of double layer(dl) charging/discharging process has been studied.The improvement of AC was carried out via a secondary activation under steam in the presence of catalyst NiCl2, and the suitable condition was found to be a heat treatment at about 875 ℃ for 1 h.Under those conditions, the discharge specific capacitance of the improved AC increases up to 53.67 F/g, showing an increase of about 25% as compared with that of as-received AC.The good rectangular-shaped voltammograms and A.C.impedance spectra prove that the high rate capability of the capacitor made of the improved AC is enhanced significantly.The capacitance resistance(RC) time constant of the capacitor containing the improved AC is 1.74 s, which is much lower than that of the one containing as-received AC(an RC value of 4.73 s).It is noted that both kinds of AC samples show a similar specific surface area and pore size distribution, but some changes have taken place in the carbon surface groups, especially a decrease in the concentration of surface carbonyl groups after the improvement, which have been verified by means of X-photoelectron spectroscopy.Accordingly, it is suggested that the decrease in the concentration of surface carbonyl groups for the improved AC is beneficial to the organic electrolyte ion penetrating into the pores, thus leading to the increase in both the specific capacitance and high rate capability of the supercapacitor.
    Kinetics and Mechanism of Exothermic First-stage Decomposition Reaction of 2,6-Bis (2,2,2-trinitroethyl)glycoluril
    HU Rong-zu, YANG De-suo, GAO Sheng-li, ZHAO Feng-qi, CHEN San-ping, CHEN Pei, LUO Yang, ZHAO Hong-an, SHI Qi-zhen
    2004, 20(5):  624-626. 
    Abstract ( )   PDF (1337KB) ( )  
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    The thermal behavior, mechanism and kinetic parameters of the exothermic first-stage decomposition of the title compound in a temperature-programmed mode were investigated by means of DSC, TG-DTG and IR.The reaction mechanism was proposed.The kinetic model function in differential form, apparent activation energy(Ea) and pre-exponential factor(A) of this reaction are (3/2)(1-a)[-ln(1-a)]1/3, 185.52 kJ/mol and 1017.78 s-1, respectively.The critical temperature of the thermal explosion of the compound is 201.30 ℃.The values of ΔS≠, ΔH≠ and ΔG≠ of this reaction are 72.46 J/(mol · K), 175.1 kJ/mol and 141.50 kJ/mol, respectively.
    Characterization of Microporous Activated Carbon Electrodes for Electric Double-layer Capacitors
    MENG Qing-han, LIU Ling, SONG Huai-he
    2004, 20(5):  627-630. 
    Abstract ( )   PDF (704KB) ( )  
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    A ctivated carbons (ACs) with a wide range of surface areas were made from petroleum coke by means of KOH activation.The electrochemical characterization was carried out for several activated carbons used as polariz able electrodes of electric double-layer capacitors (EDLCs) in an aqueous electrolytic solution.The porous structures and electrochemical double-layer capacitance of the activated carbons were investigated by virtue of nitrogen gas adsorption and constant current cycling(CCC) methods.The relationship among the surface area, pore volume of the activated carbons and specific double-layer capacitance was discussed.It was found that the specific capacitance of ACs increased linearly with the increase of surface area.The presence of mesopores in the activated carbons with very high surface area(＞2000 m2/g) was not very effective for them to be used as EDLCs.The influence of chemical characteristics of the activated carbons on the double layer formation could be considered to be negligible.
    Thermal Decomposition Kinetics of Lead 2,4,6-Trinitroresorcinate Monohydrate
    HU Rong-zu, CHEN San-ping, GAO Sheng-li, ZHAO Feng-qi, SONG Ji-rong, SHI Qi-zhen, CHEN Pei, LUO Yang, ZHAO Hong-an, YAO Pu, LI Jing
    2004, 20(5):  631-636. 
    Abstract ( )   PDF (1826KB) ( )  
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    The non-isothermal decomposition of lead 2,4,6-trinitroresorcinate monohydrate, Pb (TNR) · H2O.was investigated by means of TG-DTA, DSC and IR.The thermal decomposition mechanism and the dissociated kinetics were also investigated.The kinetic parameters were obtained from the analysis of the DSC curves by integral and differential methods.The most probable kinetic model function of the dehydration reaction of Pb(TNR) · H2O was suggested by the comparison of the kinetic parameters.
    Physico-chemical Characterization of Mo-Hβ Zeolite Catalysts
    LIU Sheng-lin, HUANG Sheng-jun, XIN Wen-jie, QIN xin-hua, XIE Su-juan, XU Long-ya
    2004, 20(5):  637-639. 
    Abstract ( )   PDF (485KB) ( )  
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    A series of Mo-impregnated Hβ samples, with MoO3 loading in Hβ zeolite in the mass fraction range of 0.5%-6.0%, were studied by means of XRD and IR in order to characterize their structures.Mo/Hβ samples' crystallinity almost linearly decreases with increasing the amount of MoO3 loaded.The IR spectra and XRD patterns suggest that the progressive destabilization of the Hβ zeolite structure is caused by increasing Mo loading in (MoO3+Hβ zeolite).During the calcination, Al2(MoO4)3 formed from the dealumination of Hβ zeolite, causes the substantially partial breakdown of the zeolite framework when the Mo loading in MoO3 +Hβ is relatively high.
    Structure and Properties of Semiconductor Microclusters GanPn(n=1-4): A First Principle Study
    ZHANG Cai-rong, CHEN Hong-shan, WANG Guang-hou
    2004, 20(5):  640-646. 
    Abstract ( )   PDF (1016KB) ( )  
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    The possible geometrical structures and relative stabilities of semiconductor microclusters GanPn(n= 1-4) were studied by virtue of density functional calculations with generalized gradient approximation (B3LYP).For the most stable isomers of GanPn(n= 1-4) clusters, the electronic structure, vibrational properties,dipole moment, polarizability and ionization potential were analyzed by means of HF, MP2, CISD and B3LYP methods with different basis sets.
    Electrochemical Performance Studies of Tin Oxide Prepared by Sol-Gel
    MA Yue, ZHOU De-feng, ZHANG Jing-ping, HAO Jie, XIE Hai-ming, ZHANG Xi-yan, SU Zhong-min, WANG Rong-shun
    2004, 20(5):  647-651. 
    Abstract ( )   PDF (814KB) ( )  
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    SnO2 prepared with the sol-gel technique at different temperatures was used as an anode material of the lithium-ion battery.We obtained the qualititave relationship between the electrochemical performance of tin oxide anode material and each of its carbon component, particle size, structure and surface morphology in detail.It was found that the best electrochemical performance can be reached by controlling the physical characteristics of SnO2, which was affected greatly by the treatment temperature.The SnO2 obtained at 600 ℃ was pure.When it was used as the anode material of the lithium-ion battery, it demonstrated a high initial specific capacity of 770 mA · h/g.
    Preparation and Characterization of Aromatic Polybenzoxazoles Copolymers Containing 2,6-Naphthalene Units
    LI Lei, FAN Xing-he, ZHAO Xiao-dong, ZHOU Jing-lun, CHEN Xiao-fang, WAN Xin-hua, ZHOU Qi-feng
    2004, 20(5):  652-655. 
    Abstract ( )   PDF (718KB) ( )  
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    A series of polybenzoxazoles (co)polymers bearing crankshaft units in the main chain was synthesized by the conventional solution polycondensation of 4, 6-diaminorescinol dihydrochloride, terephthalic acid (TA)and 2,6-naphthalene dicarboxylic acid(NDA).All of the polymers show lyotropic liquid crystal behavior in polyphosphoric acid(PPA) and methanesulfonic acid (MSA).The polybenzoxazoles exhibit an excellent thermal resistance although the crankshaft monomer has been introduced into the polymer backbone.The temperature for the 5% weight loss of all the polymers is above 600 ℃.The X-ray diffraction analysis results show that the series of the polymers has a high crystallinity.The introduction of NDA makes a slight decrease in the thermal resistance of the polymers.The maximum absorption peak in the UV-Vis spectra can be adjusted according to the amount of 2,6-naphthalene units in the polymers, which indicates the potential application of the polymers as optoelectric materials.
    Covalentely Attached Multilayer Films Comprising Phthalocyanine and Their Photoelectron Conversion Properties
    ZANG Mao-feng, YAO Qiao-hong, YANG Zhao-hui, HUANG Chun-hui, CAO Wei-xiao
    2004, 20(5):  656-659. 
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    The photosensitive multilayer films from sulfonated metal-free, sulfonated copper-, and sulfonated nickel-phthalocyanines were fabricated with diazoresin layer by layer on a substrate via electrostatic interaction by the self-assembly technique.Under UV irradiation, the linkage nature between the layers of the film is converted from the electrostatic bonding to covalent bonding.The covalently attached multilayer films are very stable towards polar solvents and salt aqueous solutions.The photovoltaic properties of the covalently attached film can be determined by means of a traditional three-electrode photoelectrochemical cell in aqueous solutions with KCl as the supporting electrolyte.The photocurrent determination has shown that the sulfonated copper-containing phthalocyanine films possess a higher photocurrent value than sulfonated metalfree and sulfonated nickel-containing phthalocyanine films.
    Vibration-dependent Crystal Form of Isotactic Polypropylene under Nonisothermal Crystallization
    SHANGGUAN Yong-gang, TONG Li-fang, PENG Mao, ZHENG Qiang
    2004, 20(5):  660-664. 
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    A study concerning the effect of vibration on the crystal structure and morphology for isotactic polypropylene(iPP) was conducted.The crystallite size, crystal structure and crystallinity of iPP under or without vibration treatment were investigated by means of differential scanning calorimetry(DSC) and wideangle X-ray diffraction(WAXD).The results reveal that the crystallinity of the vibrated samples decreases at a high cooling rate, but it remains constant at a low cooling rate because of the chain relaxation of iPP.It has been found that vibration obviously increases the content of β-form of crystal phase and the amount of β-crystal mainly depends on the vibration amplitude.
    A Paleogenomic Algorithm for Reconstruction of Ancient Operons from Complete Microbial Genome Sequences
    WANG Yu-hong, LI Wei, FANG Xue-xun, John P. Rose, WANG Bi-Cheng, LIN Da-wei
    2004, 20(5):  665-667. 
    Abstract ( )   PDF (516KB) ( )  
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    Syntheses of Novel Flavones Containing Schiff Base Moiety
    TANG Li-jun, ZHANG Shu-fen, GAO Wen-tao, YANG Jin-zong
    2004, 20(5):  668-670. 
    Abstract ( )   PDF (415KB) ( )  
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    Skeletal Rearrangement of Substituted Benzaldoxime 3-(2,2-Dichlorovinyl)-2,2-dimethyl Cycle-propane Carboxylates under EI-MS
    XIA Yan, HE Shui-ji, CHEN Qi-fa, ZUO Yu-min
    2004, 20(5):  671-673. 
    Abstract ( )   PDF (1601KB) ( )  
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