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    10 January 2006, Volume 27 Issue 1
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    Contents
    高等学校化学学报2006年第27卷第1期目次
    2006, 27(1):  0-0.  doi:
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    Hydrothermal Synthesis   and  Structures  Characterization  of a Novel Three-dimensional Iron Phosphite: (H3O)2·[FeⅡ5(HPO3)6]
    FAN Yong, LI Guang-Hua, YU An-Hui, HE Xin, ZHANG Zhi-Ming, SONG Tian-You, FENG Shou-Hua
    2006, 27(1):  1-4. 
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    The replacement of phosphate with phosphite in the transition metal phosphates has attracted more and more research efforts. To date, only a few phosphite materials containing Fe cation have been reported. Our group has developed the hydrothermal synthesis of many novel metal phosphites. Here we reported another three-dimensional iron phosphites (H3O)2·[FeⅡ5(HPO3)6]synthesized under mild hydrothermal conditions and characterized by single crystal X-ray diffraction. The title compound crystallized in the trigonal space group P3c1, with unit cell parameters, a=1.026 9(5) nm, b=1.026 9(5) nm, c=0.929 5(6) nm, and Z=2. The compound formed three-dimensional frameworks with six-membered channels along the c axis. The Fe centers in the frameworks adopt slightly distorted octahedral coordination geometry and were bridged by the pseudo-pyramidal phosphites. The temperature dependence of magnetic susceptibility measurements for the title compound indicates the occurrence of antimagnetic interaction between Fe ions. Neel′s temperature for Title compound is 6.43 K. Above Neel′s temperature materials have paramagnetic behavior which obeys to Curie-Weiss equation. The Curie constants is 23.4 emu\5K-1\5mol-1. The effective magnetic moment of the compound  at 300 K is 4.25μB per Fe 2+ .

    Silver Biomimetic Mineralization in vitro with Inorganicbinding  Peptide AG4(NPSSLFRYLPSD) Immobilized on PET Film
    ZHANG Xu, CHEN Jin-Chun, YANG Peng, YANG Wan-Tai
    2006, 27(1):  5-8. 
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    AbstractAG4(NPSSLFRYLPSD)is a peptide that specifically and selectively binds to silver resulting from Dr. Stony′s phage display peptide combination library. The peptides that have similar characteristic are defined as inorganicbinding peptides. In our experiment, AG4 was adsorbed on the surface of protonated PET-N(CH3)2 film for studying its biomineralization behavior in vitro. Based on the XPS results of both silver crystallite on AG4/PET-N+(CH3)2 film and AgNO3 salt, we approved that Ag+ exactly reduced to Ag0 and further formed silver crystallites. In addition, the images of SEM revealed that silver crystallite was 1-2 μm in size with a square shape and a triangular shape. At last, we discussed the reaction mechanism possibly occurring in this process.

    Adsorption Behavior of VB12 on Mesoporous Carbon Molecular Sieves
    with Different Pore Diameters
    GUO Zhuo, ZHU Guang-Shan, XIN Ming-Hong, GAO Bo, QIU Shi-Luan
    2006, 27(1):  9-12. 
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    AbstractThe CMK-3-130 exhibits the largest adsorption capacity than CMK-3-100 and CMK-3-150. Mesoporous carbon sieves were prepared from SBA-15 materials at different temperatures. This allows the synthesis of mesoporous carbons sieves with pore dismeters in the range from 3.7 nm(CMK-3-100) to 6.3 nm(CMK-3-150).The mesoporous carbons sieves were studied in the adsorption of VB12 from water solutions. The maximal adsorption capacity of 412.5 mg/g was found for CMK-3-130, which is probably a consequence of its highly ordered mesostructures and larger pore.

    Effects of La 3+ on Transient Outward K+ and Delayed Rectifier K+ Currents Kinetics in Hippocampal Neurons of Rat
    DU Hui-Zhi, YANG Pin
    2006, 27(1):  13-16. 
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    Using the whole cell patchclamp technique, the effects of La 3+ on transient outward K+ and delayed rectifier K+ currents kinetics were studied in acutely isolated rat hippocampal neurons. The results show that La 3+ in the external solution inhibited IA(K+ current) in a concentration and voltage-dependent manner. The La 3+ concentration of 10-5 mol/L could significantly affect Vh of the activation curve and inactivation curve of IA, respectively, but the k was not changed. La 3+ in the external solution did not affect IK(platform current) and the activation curve. These may contribute to abnormity of the central nervous system by La 3+ .

    Synthesis of a Mesoporphyrin Dimer by Direct Condensation Between Two Mesocarboxy Group of Porphyrin Ring
    FA Huan-Bao, ZHAO Lang, WANG Xing-Qiao
    2006, 27(1):  17-19. 
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    A meso-porphyrin dimer was synthesized by direct condensation between two meso-corrboxy group of porphyrin ring. The purple rude product was purified on a silicon gel column. The identity of the mesoporphyrin dimer was confirmed by the methods of elemental analysis, MS, 1H NMR, UV-Vis and IR. The synthesis method is simple and the rude-product is easy to be purified with a high yield.

    Synthesis of High Performance Silicalite-1 Zeolite Membranes
    CHEN Hong-Liang, LI Xian-Shuo, LIU Jie, YANG Wei-Shen
    2006, 27(1):  20-22. 
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    Synthesis of high performance Silicalite-1 zeolite membranes on silica tubes was first reported in this paper. After two-step insitu hydrothermal synthesis, well intergrown Silicalite-1 zeolite membranes were synthesized on silica tubes after aging at 75 ℃ for 12 h. The Silicalite-1 zeolite membranes were characterized by SEM. The separation performance towards ethanol/water mixtures was evaluated by pervaporation. With temperature increasing, the flux of S-1 membrane, increased from 0.2 kg·m-2·h-1 at 30 ℃ to ca. 1.0 kg·m-2·h-1 at 80 ℃, while the separation factor decreased from 110 to 89. These results showed that silica supports may be more suitable for preparing high performance Silicalite-1 membranes.

    Preparation of SiC Hollow Spheres from SiO2@PPy Core/Shell Structure
    ZHU Yu-Fang, FANG Ying, LIU Ya-Yun, SHI Jian-Lin
    2006, 27(1):  23-25. 
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    AbstractA SiO2@PPy core/shell structure was synthesized by performing the polymerization of pyrrole monomers around SiO2 spheres. For the first time, the SiC hollow spheres with a high surface area was prepared from the SiO2@PPy with a core/shell structure by using a carbothermal reduction reaction technique. The preparation process and the structures of the products were characterized with XRD, TEM, SEM, N2 adsorption-desorption isotherms and XPS. The results indicate that β-SiC hollow spheres with a specific surface area of 101.3 m2/g could be prepared from the SiO2@PPy with a core/shell structure.

    A  Computational Method Based on Information Fusion  for Evaluating the Similarity of Multiple Chromatographic Fingerprints of TCM
    FAN Xiao-Hui, YE Zheng-Liang, CHENG Yi-Yu
    2006, 27(1):  26-29. 
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    AbstractAn computational method based on information fusion is developed to evaluate the similarity of multiple chromatographic fingerprints of TCM,  where it solves a current  key problem on evaluating the similarity of multiple fingerprints. In this method,  the information of individual fingerprint was combined by using serial or parallel information fusion strategy at raw data level,  and then the integral similarity of multiple fingerprints was calculated by comparing their fusion results. Subsequently,  this method was applied to simulated datasets and a set of Compound Danshen Dripped Pills(CDDP) samples. The results indicate that,  by this method,  the similarity among multiple chromatographic fingerprints of TCM can be calculated,  and the lot-to-lot consistency of samples can be evaluated quantitatively.

    Studies on Column Size Scale-up and Flow Profile in Conical Shape Liquid Chromatographic Column of 10° by Visualization Method
    GUAN Wen-Na, TAN Feng, GUAN Ya-Feng
    2006, 27(1):  30-34. 
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    AbstractAn improved visualization device made of polymethyl methacrylate(PMMA), packed with C18, was utilized to study the 3D flow profile of conical columns with an angle of 10°. The outside wall of the conical columns was a rectangular shape in order to improve the transparency property of the column wall and reduce the deformation of image for better observation of the flow profiles of colored solutes inside the column. The influence of mobile phase flow rate, particle size and shape on the flow profile of a colored band was studied both for a 5 cm long column and a scaled-up column of 4 fold in volume. The experimental results show that the flow rate of mobile phase has a little influence on the flat flow profiles of the iodine band while the properties of stationary phase have a certain influence on them. The flow profiles of the scaled-up column are flat during the whole chromatographic process, and the efficiency and resolution of the column are also increased in accordance with theoretical prediction. The results indicate that the 10° conical columns can be proportionally scaled up while still keeping the flat flow profile and superior column efficiency than conventional column.

    Multi-components Comprehensive Evaluation  on Chemical Stability  of Fermented Red Yeast Rice
    LI Yong-Guo, LIU Hong, WANG Zheng-Tao, HU Zhi-Bi
    2006, 27(1):  35-38. 
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    A novel multi-components comprehensive evaluation approach in the present research is superior to the conventional single marker-orientation method in being more reasonable and suitable for the demonstration of the chemical stability of Chinese Medicines(CMs). An application of this proposed method on the chemical stability study of fermented red yeast rice, one of traditional Chinese healthcare food and medicines, was addressed. The accelerated testing(40 ℃, 75%RH) for 3 months and the stress testing under five storage conditions involving  high temperature(80 ℃, 60 ℃), high humidity(25 ℃ and 92.5%RH) and high humidity with high temperature(60 ℃ and 75%RH) and light effects were carried out. A complex criteria, given name “variability percentage[V(%)]” was initiated to display the combination of multi-components stability in CM. The results show that variability percentage[V(%)] generated from the sum of monacolin lacton and acid forms was preferred to assess the stability of red yeast rice. This proposed way could be used as technique platform and applied to stability evaluation of other CMs, which could provide detail information on the inter- and intra- varieties of multi-components in CM.

    A Novel Method of Fast Sample Preparation for Determination of Sulfur Dioxide in  Foodstuffs
    MA Juan, WANG Xing-Hua, LI Bao-Hua, HUANG Feng, XIE Fei, YU Ai-Min
    2006, 27(1):  39-42. 
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    The semimicro fractional distillation and the semiconducting refrigeration techniques were applied to the fast determination of sulfur  dioxide in foodstuffs. A novel distilling method which did not require mercuric  absorbent and cooling water was proposed. A fast distillation equipment which,  can complete the distillation of sulfur dioxide in foodstuffs in 15 min,  was developed. The effects of acidity, volume of sample solution, volume of distillate  and time of distillation on distillation yield of sulfur dioxide were studied. The calibration curve is linear at the mass SO2 content  of 1.0-100.0 mg/kg sample,  the correlation coefficient is over 0.998, the lower limit of detection is 1.0 mg/kg.   With the method and the equipment mentioned above, the interference of the sample color and the pollution of the mercuric absorbent can be avoided, and the analysis of each sample can be completed in 30 min including the sample preparation time. More than 20 kinds of practical samples were analyzed.   The results  are in good agreement with the results obtained by the standard method, and the relative errors of determined values are less than 5% when the sulfur SO2 concentrations are more than 10 mg/kg. 

    A Novel Electrochemical Sensor for the Determination of Nitric Oxide
    WANG Ya-Zhen, CHEN Yan-Guo, HE Zhi-Ke, HU Sheng-Shui
    2006, 27(1):  43-46. 
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    A novel water-soluble poly(p-phenylenevinylene) derivative was electropolymerized at glass carbon electrode by cyclic voltammetric method or two-potential steps method to develop a sensitive nitric oxide(NO) sensor.  The experimental results show  that the sensor exhibits apparent current response to NO by cyclic voltammetry.  Two anodic peaks potential  significantly shifted negatively copared with bare GCE.  The oxidation current(measured by chronoamperometry) is linear with NO concentration ranging from 1.8×10-7 to 1.0×10-4 mol/L with a linear coefficient of 0.999 3.  The detection limit of NO is 2.3×10-8 mol/L(S/N=3).  The electrochemical behavior of NO on this sensor was also characterized by rotating disk electrode.  The results also indicate that the oxidation of NO proceeds in two steps.  Rotating disk experiments yield a diffusion coefficient of NO in 0.1 mol/L PBS at 20 ℃, that is DNO=2.92×10-5 cm2/s.  The value of DNO was validated by chronocoulometry.

    Preparation and Evaluation of Open-tubular Capillary  Electrochromato-graphy  Column with the Poly(amidoamine)(PAMAM) Dendrimers as Bonded Stationary Phase
    ZHANG Zhi-Sheng, YANG Yi
    2006, 27(1):  47-51. 
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    The objective of our study is to explore the potential of poly(amidoamine)(PAMAM) dendrimers as a bonded stationary phase in open tubular capillary electrochromatography(CEC). 1G, 2G and 3G poly(amidoamine)(PAMAM) dendrimers were bonded to the interior wall of silica capillaries through a 3-aminopropyltriethoxysilane linker step by step. The obtained columns were characterized by CEC process. The results show that the electroosmotic flow(EOF) gradually reduced with increasing PAMAM generation. The performances of the column were evaluated by the separation of alanine and praline. The results indicate that the resolution of alanine(Ala) and proline(Pro) was gradually improved with increasing the amount of PAMAM generation. By open-tubular capillary electrochromatography column modified with the 3rd  generation PAMAM, the baseline separation of the alanine and proline can be obtained. Five underivatized amino acids, arginine(Arg), alanine(Ala), proline(Pro), histidine(His) and methionine(Met), were successfully separated by OCEC modified with 3G PAMAM and by using UV detection at 200 nm. The reproducibility and stability of the column were satisfactory.

    Tandem Mass Spectrometry Analysis of Saponins from Sapindus mukurossi
    LI Rui, ZHOU Yan, YANG Yong-Cheng, WU Zhi-Jun, DING Li-Sheng
    2006, 27(1):  52-54. 
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    The saponins of Sapindus mukurossi was analyzed by tandem mass spectrometry. The molecular weights of 12 saponins from the total saponin of S. mukurossi were determined by positive and negative ions ESI-MS and their molecular formula were acquired by HR-ESI-MS. Furthermore, the four hederagenin saponins and seven acyclic sesquiterpene saponins were identified based on the tandem mass spectrometry.

    Studies on Blind Separation of Gas Sensor Array Signals
    WEI Guang-Fen, TANG Zhen-An, CHEN Zheng-Hao, YU Juan, WANG Li-Ding, YAN Gui-Zhen
    2006, 27(1):  55-57. 
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    Responses of a Micro-hotplate based integrated gas sensor array to CO and CH4 were measured with an automated gas sensor calibration system. Combining with the blind source separation(BSS) techniques, the blind separability in gas mixture analysis was discussed. The widely used BSS approach-Independent Component Analysis(ICA) was adopted to verify the proposed method by analyzing the gas mixtures of CO and CH4. The analysis results demonstrate that BSS was an effective way to extract the information of gas components in mixtures, from which the gas concentrations can be estimated. The average relative quantification errors were 9.37% and 8.11% for CO and CH4, respectively, in the specified concentration ranges.

    Studies on Topological Isomers(Ⅰ)Spectrum Properties and Structure Identification of C-Shaped and
    S-Shaped Topological Isomers
    ZHOU Bao-Han, YIN Guo-Dong, LIU Xiao-Peng, WU An-Xin
    2006, 27(1):  58-61. 
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    With the development of the supramolecular chemistry, a type of novel stereoisomers with the same chemical formula and connectivity but different folding shapes has been found. These topological stereoisomer have different three-dimension structures which result in its different functions in molecular recognition, assembly and aggregation. In this paper we reported four synthesized topological isomers whose chemical configurations were characterized by means of 1H NMR, 13C NMR, IR, UV and SEM. It is found that the topological configuration of C-shaped and S-shaped molecules can be identified by 1H NMR, and the topological isomers of S-shaped cis(SC)and trans(ST); C\|shaped cis(CC)and trans(CT)can be identified by 13C NMR. There is little difference in IR, UV and SEM of the four isomers.

    Regulation of Hydrogen Production by Uncoupler CCCP in Green Algae Chlamydomonas reinhardtii
    RAN Chun-Qiu, ZHANG Wei, YU Xing-Ju, JIN Mei-Fang, DENG Mai-Cun
    2006, 27(1):  62-66. 
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     Uncoupler,  carbonylcyanide-m-chlorophenylhydrazone[CCCP],  can markedly inhibit the photochemical activity of photosystem Ⅱ and repress the rate of photosynthetic oxygen evolution.  As a result,  the anaerobic condition can promptly induce hydrogenase expression and accelerate hydrogen photoproduction under the  continuous illumination by Chlamydomonas reinhardtii.  When C. reinhardtii cultured in TAP medium and treated with 0,  5 and   15 μmol/L CCCP under the continuous illumination,  the photochemical activity of algae could not be obviously inhibited.  But 15 and 20 μmol/L CCCP could markedly depress the photochemical activity and substantial amount of hydrogen gas was photoproduced.  The photochemical activity of C. reinhardtii cultured with TAP-S at all concentrations of CCCP under the continuous llumination was distinctly inhibited and the cultures photoproduced hydrogen gas rapidly.  The algae of C. reinhardtii cultured with TAP and TAP-S medium,  different concentrations of CCCP altered the process of hydrogen metabolism and the efficiency of utilization and conversion of solar energy by the center of PSⅡ.

    Deproteinization from Epimedium Polysaccharide by Macroporous Adsorption Resin
    LI Rui-Jun, LI De-Yao, ZHANG Xian-Feng, LIN Dong-Chun, LIU Hong-Min
    2006, 27(1):  67-70. 
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    To deproteinize from crude Epimedium polysaccharide, ADS-7 type of resin was selected from four kinds of macroporous adsorption resins.  The influence factors, such as pH value, tannic Acid, elution volume and so on, were investigated.  The content of proteins in crude Epimedium polysaccharide decreased from 1.2% to 0.035%.  The results show that deproteinization from crude Epimedium polysaccharide by macroporous adsorption resin is a feasible method.

    Degradation Character of a Alginate Lyase from Vibrio sp.  WYA
    ZHANG Zhen-Qing, YU Guang-Li, ZHAO Xia, WANG Yuan-Hong, LV Zhi-Hua, GUAN Shi-Hu
    2006, 27(1):  71-74. 
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    The characterization of an alginate lyase, which was purified from Vibrio sp.  WYA, was studied.  This enzyme can specific ally degrade alginate to produce oligosaccharides, the oligosaccharides was separated by BioGel P6 column, and purified by Mono Q column.  The degree of polymerization and structure of these oligosaccharides were confirmed by HPTLC, ESIMS and NMR methods, respectively.  The results show that, all the oligosaccharides are trimers, and have structures of DGG, DMG and DMM, respectively. The minimal recognition and hydrolysis fragment of this enzyme is hexasaccharide, and the degradation site occurred on the non\|reducing end mannuronic acid of the polysaccharide.  The degradation mechanism of this kind of enzyme is very unique, and very useful for the alginate structure analysis, and alginate trisaccharides preparation. 

    Synthesis and Properties of Photochromic 2,2-Diarylnaphthopyrans Compounds
    TAN Ting-Feng, FU Yi-Fang, HAN Jie, LONG Mei-Li, MENG Ji-Ben
    2006, 27(1):  75-78. 
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    On fading rate and maximum absorbent intensity consideration, a series of novel 2,2-diarylnaphthopyrans were designed and synthesized purposefully through the reaction of Gringnard reagents and naphthopyran biones, respectively. The structures of all the compounds were determined by 1H NMR, IR, MS, and elemental analysis. Combined with UV-Vis, the photochromic properties of these compounds were studied intensively. The results indicated that the maximum absorbent wavelength of compounds in solutions will shift to longwave  with the increase of electron\|donor  effect under UV\|Vis irradiation. Moreover, the relationship between the structure and photofading rates was analyzed. The laws between photofading rate and substituent position were preliminarily explored. The speed of fading rate principally lies on the degree of freedom of C—C bond rotation. These laws gave us a valuable reference to synthesize the practical organic photochromic compounds.

    Proteomic Analysis of Proteins with Altered Expression Induced
    by Phenylephrine in Neonatal Rat Cardiomyocyte
    LIU Ning, LI Zi-Jian, LIU Zhi-Qiang, LIU Shu-Ying, HAN Qi-De, ZHANG You-Yi
    2006, 27(1):  79-81. 
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    AbstractIn order to find candidate proteins that are potentially associated with the phenotype in neonatal rat cardiomyocytes treated with phenylephrine(PE),   the differential proteins expression pattern after α-adrenergic receptor stimulation in neonatal cardiomyocytes was analyzed by  using a series of methods,  including two dimensional polyacrylamide gel electrophoresis,  PDQuest 2-DE software analysis and peptide mass fingerprint mapping based on MALDI-TOF-MS.  The good two-dimensional  pattern with a high resolution and reproducibility was obtained.  Totally 14 differential protein spots were found.  Out of these,  11 proteins were preliminarily identified. Desmin, Txndc5, etc. were found to be up-regulated in PE-treated cardiomyocytes, while caspase-11, 4-hydroxyphenylpyruvic acid dioxygenase, etc. were found to be down-regulated. It suggests that the differential expression analysis of proteome may be useful to the further study of the related proteins and the molecular markers of cardiovascular diseases.

    Synthesis of 1,3,5-Tri{3-[2,4,8,10-tetra\|oxa-9(3,5-di(2,6-dioxa-4,4-dihydroxymethylcyclohexyl)phenyl]spiro\[5.5]undecyl}benzene for Novel Dendrimer
    WEI Rong-Bao, CHEN Su-Zhan, LIANG Ya, LIU Xiu-Meng, LI Hong-Bo
    2006, 27(1):  82-84. 
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    Dendrimers are the subject of intense attention recently because of their anticipated potentialities and the peculiar structural properties.  A novel synthetic route for the preparation of functionalized dendrons built on the 1,3,5-benzenetricarboxaldehyde core and endowed with a periphery of pentaerythritol groups has been developed.  1,3,5-Tri(2,6\|dioxa-4,4-dihydroxymethyl cyclohexyl) benzene(1) was synthesized by the condensation of 1,3,5\|benzenetricarboxaldehyde with pentaerythritol in the presence of hot CHCl3 and p-methyl benzene sulfonic acid  with 55% yield. By turning 1,3,5-benzenetricarboxaldehyde into its trioxime, it was protected to decrease the cross\|linked reaction with compound 1 both including many groups.    The reaction of compound 1 with 1,3,5-benzenetricarboxaldehyde trioxime and pentaerythritol afforded 1,3,5-tri{3-[2,4,8,10 -tetra-oxa-9(3,5-di(2,6-dioxa-4,4-dihydroxymethylcyclohexyl) phenyl\]spiro[5.5]undecyl}benzene (2) by using I2 as the catalyst, and the yield was 25.2%.  Product 2 and its intermediates were identified by IR, 1 H NMR, MS spectra and elemental analysis.

    Effect of Support Acidity on Selective Catalytic Reduction of
    NO by C3H6 over Cu-based Pillared Clay Catalyst
    LIN Qi-Chun, LIN Wei-Ming, HAO Ji-Ming, LI Jun-Hua, FU Li-Xin
    2006, 27(1):  85-88. 
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    New pillared clay catalysts were studied for NOx removal by hydrocarbon in the presence of oxygen. The purpose of this work is to study the role of support acidity in the selective catalytic reduction(SCR) of NO by propylene. In this paper, montmorillonite was pillared by multi-oligomeric hydroxyl cation to synthesize Al--Ce-PILC and then treated by NH4NO3 and(NH4)2SO4 respectively. Cu-based pillared clay catalysts(Cu/Al-Ce-PILC) were prepared by impregnation and applied to C-H6SCR of NO. The influence of treatment methods on the structure and acidity of Al-Ce-PILC and the performance of Cu/Al-Ce-PILC were characterized by Py-IR,IR and DSC. The results show that, both Lewis and Br-nsted acid sites exist on Al-Ce-PILC, with Lewis acid sites as the main ones, and the maximum NO conversion of Cu/Al-Ce-PILC reaches only 18.5%. As a result of the NH4NO3 treatment, the Lewis acid sites increase, while NO conversion decreases. As for Al-Ce-PILC treated by(NH4)2SO4, more Br-nsted acid sites are identified and a superacid structure is formed, and the NO conversion over Cu/Al-Ce-PILC catalyst increases remarkably to 50.2% at 350 ℃, which is associated with the change of the support acidity. It is concluded that Br-nsted acid sites are necessary for the SCR reaction of NO because they promote the absorption of C3H6 to form proper intermediates that are active for the reduction of NO to N2. The increase of Br-nsted acid sites plays a vital role in the improvement of catalytic performance.

    Spatial Periodic Analytic Solution for Three Variable
    Reaction-diffusion Equations
    LV Ling, LI Gang
    2006, 27(1):  89-91. 
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    The stability of three variable reaction-diffusion equations was analyzed. The critical value μc was ascertained when the reaction system changes from the stable state to the unstable state by adjusting parameter μ, and the system takes on a spatial periodic order structure. The analytic solution describing the spatial period was obtained and it is accordant with experimental result.

    A Valence Bond Study of Electron Transfer Process in
    Alkane Systems
    LIN Yong-Hui, SONG Ling-Chun, MO Yi-Rong, WU Wei
    2006, 27(1):  92-95. 
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    The electron transfer process in trans alkyl chain systems was studied by valence bond theory at BOVB and VBCIS levels. For the cation systems, the results obtained with the two methods are both in good agreements with experimental values. For the anion systems, the results obtained with VBCIS method matches fairly the experimental values, while the β value of BOVB was higher than that of experiment. The results obtained from our study show that the valence bond theory provides a potential tool for studying the electron transfer process.

    Localization Character of LFMO and NBO and Interaction Energy Analysis
    LIU Xiang-Wen, BAO Peng, YU Zhong-Heng
    2006, 27(1):  96-99. 
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    To analyze the vertical resonance energy(VRE) of C12H6, the localized fragment molecular orbital(LFMO) and the natural bond orbital(NBO) basic sets are constructed. Then, the NBO and Morokuma′s SCF energetic analysis are performed over each of them. The VRE, obtained from the NBO electronic analysis, is always unstable. But the VRE, obtained from Morokuma′s SCF energy partition, depends on the basis set. In addition, the singly diagonalized process for the Fock matrix in the NBO energetic analysis ignores the electronic coupling between σ and π systems. In a word, the NBO basic set and its energetic analysis seems to be unreasonable as far as the calculation of VRE is concerned.

    Effects of Fe-Doping and Natural Zeolite-Support on the Photocatalytic Activity of TiO2
    HOU Tian-Yi, JIANG Yin-Shan, LI Fang-Fei, SUN Shen-Mei
    2006, 27(1):  100-103. 
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    Key Laboratory of Automobile Materials,  Ministry of Education, College Department of Materials Science and Engineering,  Jilin University,  Changchun 130026,  China

    Preparation and Forming Mechanism of Porous Film with
    Low Dielectric Constant
    XU Hong-Yao, WANG Xian-Biao, WU Zhen-Yu
    2006, 27(1):  104-107. 
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    AbstractPOSS sol-gel as the porous silica template was prepared by hydrolyzation and condensation of KH-570(γ-methacryloxypropyltrimethoxy silane). Porous film with a low dielectric constant was obtained by calcination of POSS template. The process and mechanism of film formation were investigated by FTIR and its structure was characterized by 29Si NMR, Ellipsometr, N2 adsorptiondesorption and TEM. The results show that the film possesses uniform pore with about 1 nm size, dielectric constant 2.5, and Sbet=384.1 m2/g and the effects of the surface modification reagent and it′s concentration on the dielectric property of film were discussed.

    Adsorption of Methanol on Surface of Zinc Oxide
    WANG Mou-Hua, DONG Qiang-Nian, ZHANG Wen-Yu, WEI Wei, SUN Yu-Han
    2006, 27(1):  108-111. 
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    AbstractThe adsorption of methanol on the surface of zinc oxide was investigated by in situ FTIR and pulse reaction. The FTIR results show that methoxyl group was formed from the adsorbed methanol on the surface of zinc oxide, and its amount increased with increasing adsorption temperature. Further investigation indicates that methoxyl group was produced only by the reaction of methanol with surface hydroxyl group. It was also revealed that methoxyl group vanished quickly when it was exposed to water vapor. In the pulse reaction, water was detected while methanol was adsorbed on the the surface of zinc oxide, and then methanol was found while methoxy group contacted with water. Thus, the reaction of methanol with hydroxy group on the surface of zinc oxide surface was reversible.

    Gas\|phase Reaction of Herbicide 2-Methyl|4|chlorophenoxy Acetic Acid(MCPA) with OH Radicals
    HAN Lei, SHU Tong, SUN Feng-Long, CHANG Jing
    2006, 27(1):  112-115. 
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    The investigations about the atmospheric degradation of organic herbicides became more and more important in China.  In our present research, the rate constant of the reaction of 2-methyl-4-chlorophenoxy acetic acid(MCPA) with OH radicals was measured by a long path quartz reactor connecting with Fourier Transform Infrared Spectroscopy(FTIR).  At 23 ℃ and under one atmosphere, the rate constant was determined to be 2.67×10-11 cm3/(s*mol), the atmospheric life time of MCPA was estimated to be 14.9 h.  The results show that MCPA can be degraded in  atmosphere and is not feasible to cause wide\|spreading and persisting pollution through long range atmospheric transport.

    Mechanical Ball Milling Preparation and Electrochemical Hydrogen Storage Properties of Amorphous Mg-Fe Composites
    XIAO Xue-Zhang, CHEN Chang-Pin, WANG Xin-Hua, CHEN Li-Xin, GAO Lin-Hui, WANG Li, DU Shu-Li
    2006, 27(1):  116-120. 
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    The microstructure and electrochemical properties of (2Mg+Fe)+x%Ni(mass fraction)  composites(x=0, 50, 100, 200) prepared by using the ball milling method have been investigated. The results show that there are still Mg and Fe single phase for the nickel-free mixtures of Mg and Fe powders milled for 120 h, and the discharge capacity of the nickel-free composite is less than 20 mA·h/g. However, increasing the Ni content and enhancing the milling power make it easy to form amorphous Mg-Fe structure and to reduce the crystal size. The Mg-Fe composites could reach higher amorphorization extent and the  better electrochemical properties with introducing more amount of Ni. Compared with the composites obtained by milling with the uniform balls, the composites milled with mixed balls have a higher amorphorization extent, much more homogeneous and smaller particle sizes. As x=100, the maximal discharge capacities of the composite milled for 120 h with the balls of  different sizes and the uniform balls are 542.0 and 455.3 mA·h/g, respectively.

    Electrooxidation of Hydroxypivalaldehyde at  PbO2-SPE Composite Electrode
    YU Jian-Guo, CAO Xue-Jing, ZHANG Heng-Bin, LI Fei, XU Yu-Ling
    2006, 27(1):  121-124. 
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    The lead dioxide-solid polymer electrolyte(SPE) membrane composite electrode was prepared by hot-press and electroplating methods. The electrooxidation behavior of hydroxypivalaldehyde was studied by means of cyclic voltammetric and cell voltage-overpotential curves. The current response  at the PbO2-SPE composite electrode and cell voltage were analyzed with or without liquid supporting electrolyte in the anolytes as well as in different catholytes. It was found from the experiment restuts that the PbO2-SPE composite electrode had a good electrocatalytic activity for the  oxidation of hydroxypivalaldehyde.

    Thermal Decomposition Mechanism, Non-isothermal  Reaction Kinetics of Bismuth Citrate and Its Catalytic Effect on Combustion of Double-base Propellant
    SONG Xiu-Duo, ZHAO Feng-Qi, LIU Zi-Ru, PAN Qing, LUO Yang
    2006, 27(1):  125-128. 
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    The thermal decomposition reaction of bismuth citrate in a temperature-programmed mode was investigated by TG-DTG, DSC and heating in-situ cell FTIR. The decomposition mechanism was proposed, and the kinetic parameters of the major decomposition reaction were calculated. The apparent activation energy and pre-exponential factor of the major decomposition reaction of bismuth citrate are 213.82 kJ/mol and 1 016.48 s-1 respectively. The kinetic equation of the major decomposition process can be expressed as:dα/dt=1016.48exp(-2.56188×10 4/T)[-ln(1-α)2/3]. The catalytic performance of CIT-Bi in the combustion of double-base propellant was also investigated. The result shows that CIT-Bi possesses a good catalytic function. It can markedly increase the burning rate of double-base propellant and reduce pressure exponent. Especially, when CIT-Bi together with a little carbon black(CB) is used, the catalytic efficiency is higher.

    Effects of Surface Oxidation of Carbon Nanofibers in Mixed Concentrated HNO3-H2SO4 Acid Solution on Dispersion State of Supported Pd-Pt Catalyst Particles
    TANG Tian-Di, CHEN Jiu-Ling, LI Yong-Dan
    2006, 27(1):  129-133. 
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    Catalytically grown carbon nanofibres were treated with a mixture of concentrated nitric and sulphuric acids at different temperatures. The effects of the oxidation treatment on the graphite structure and texture properties were studied by X-ray diffraction and N2-physisorption. The formation of the surface oxygencontaining groups on the surface of the carbon nanofibers was investigated by DRIFT FTIR and the ionexchange method. The Pd-Pt catalysts supported on the fresh and treated carbon nanofibres were prepared with the incipient wetness impregnation method. The Pd-Pt metal dispersion and the interaction of them with the carriers were studied by the pulses of hydrogen, the high-resolution electron microscopy and the TPRFTIR. The results demonstrated that there were no clear changes of the bulk structure and the texture properties of carbon nanofibers after the treatment in the mixed acids below 150 ℃. The concentration of the formed oxygencontaining surface groups increased with raising the treatment temperatures and it could produce a pronounced promoting effect in the dispersion of metal in the carbon nanofibers. The mechanism of the role of the surface oxygen-containing groups in improving the dispersion of Pd-Pt particles was also discussed.

    Photocatalysis Reaction for Synthesizing Methacrolein from
    Propane and CO2 over Cu/MoO3-TiO2/SiO2 Catalyst
    HU Rong-Rong, ZHONG Shun-He
    2006, 27(1):  134-139. 
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    AbstractSolid material of metaldecorated coupled semiconductors Cu/MoO3-TiO2/SiO2, prepared by the chemical modification method and the isovolumetric impregnation method, was introduced into photopromoted surface reaction(PPSR) process to synthesize methacrolein from propane and carbon dioxide. BET, XRD, TEM, IR, Raman and UV-Vis DRS experiments were used to characterize the surface structure, photon absorbing and chemisorbing ability of the material. It was shown that the semiconductors TiO2 and V2O5, dispersed well on the surface of the catalyst Cu/MoO3-TiO2/SiO2, can be coupled each other by the chemical bonds and form manifold active chemisorbed sites. The decoration of metal Cu is helpful to expend the lightresponding scope of the material, which can also improve the photo absorbing ability of the whole reaction. The active chemisorbing of CO2 and propane on the catalyst greatly promotes the photochemical synthesis of methacrolein and the selectivity of methacrolein can reach 85%, even at the lower temperature. On the basis of the experiments, the mechanism of photo-promoted surface reaction for synthesizing methacrolein from C3H8 and CO2 on Cu/MoO3-TiO2/SiO2 was discussed.

    Application of  Free Electron Laser in Aramid Processing
    WU Yan-Jie, YANG Li-Min, XU Yi-Zhuang, YANG Xue-Pingng, LI Yong-Gui, WANG Ming-Kai, WANG Du-Jin, WU Jin-Guang, XU Duan-Fu
    2006, 27(1):  140-143. 
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    Because the melting temperature of aramid is higher than its thermo\|decomposition temperature, processing of aramid fiber in the  molten state is not feasible. Here we propose an approach to process aramid fiber using infrared Free Electron Laser(FEL). The temporal structure of the FEL pulses allows the fiber to be excited to higher vibrational levels so that the polymer becomes soft enough to be processed without significant thermo-decomposition. Microscopic observation using convention optical microscope and polarized technique shows that \!necking phenomenon\" and re\|orientation occur on an aramid fibrous sample that was treated with FEL under external strain. In comparison with the the sample without treatment of FEL, significant changes are observable on the morphology of the broken aramid fiber treated with FEL. The above results strongly suggest that the aramid fiber is molten under the excitation of FEL. FTIR spectroscopic studies show that no thermal decomposition was observed on the aramid sample after FEL treatment. The above result may be helpful to develop a new way to process aramid in the future.

    Studies on Desulfurization from Cracking of Gasoline
    Catalyzed by Phase Transfer Catalyst
    DIAO Di-Shun, MA Si-Guo, LIU Cui-Wei, REN Hong-Wei
    2006, 27(1):  144-146. 
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    AbstractDesulfurization from cracking of gasoline via selective oxidation catalyzed by phase tranfer catalyst is investigated. Using cetyltrimethyl ammonium bromide(CTAB) as the phase transfer catalyst, hydrogen peroxide as the oxidant, acetic anhydride as the assistant oxidant, the effects of different conditions, such as reaction time, reaction temperature, the content of phase transfer catalyst, on the desulfurization rate are investigated. When the volume ratio of gasoline and oxidative system is 0.2, the volume ratio of hydrogen peroxide and acetic anhydride is 5, the content of phase transfer catalysis is 0.06 g, reaction time is 0.5 h, the desulfurization rate of the FCC gasoline is 80.13%. After analyzed by GC-FPD, there is no oxidized sulfur-containing compounds remained in the gasoline.


    Implicit and Explicit Internal Signal Stochastic Resonance in Calcium Ion Oscillations System
    LI Ya-Ping, LI Qian-Shu
    2006, 27(1):  147-149. 
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    AbstractThe dynamic behavior of calcium ion oscillations was investigated when noise was injected to the system located in a steady state and an oscillatory state, respectively. It was found that noise can contribute to phenomenon of implicit or explicit internal stochastic resonance(IISR or EISR), and that distance to bifurcation point was a key factor for controlling IISR or EISR. Then an external signal was added to the system, the result shows that IISR or EISR can not occur, implying an external signal destroys the cooperation of internal signal and noise. Furthermore, the difference and the similarity were discussed between IISR and EISR.

    Structure-performance Relationship of some Chinese Herb Components Containing Structural Unit of Coumarin During Binding to Bovine Serum Albumin
    LIU Xue-Feng, XIA Yong-Mei, CAO Yu-Hua, FANG Yun, ZOU Zhu-Yan, MAO Ben-Gang, DING Yi
    2006, 27(1):  150-152. 
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    The interaction between bovine serum albumin(BSA) and five active components of Chinese Herb CⅠ-CⅤ containing structural unit of coumarin was investigated by ultraviolet(UV) and fluorescence spectroscopy(FS). The intrinsic fluorescence of BSA was quenched by pharmaceuticals via forming pharmaceutical-BSA complexes. The quenching mechanism is mainly a combination of static quenching with  nonradiative energy transfer. The parameters of pharmaceutical-BSA binding process, such as statistic quenching constant KP, the apparent association constant KA, the value of binding site n, the efficiency of energy transfer E, the spatial distance r  and ΔG were obtained. The above parameters disclose the structural-performance relationship of pharmaceutical-BSA interaction as follows. The process of pharmaceutical-BSA binding is promoted strongly by both 4-methyl and 6-hydroxyl in coumarin molecule, but the latter must endure simultaneously some adverse effects caused by increment of molecular polarity and stereo hindrance. Decreasing the polarity of 7-substituent group and increasing the volume of substituting group destroys the pharmaceutical-BSA binding, and the effect is almost totally opposite to that of 6-hydroxyl.

    Theoretical Study on Host-guest Interaction Between Bis(amidopyridine)-linked Calix[4]arenes and Aliphatic Dicarboxylic Acids
    CHEN Dong-Hui, SUN Hong-Wei, CHEN Lan, CHEN Rong-Xin, YUAN Jing, CHEN Pei-Quan, YUAN Man-Xue, LAI Cheng-Meng
    2006, 27(1):  153-155. 
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    The interest in calixarenes has been related to their ability as receptors for neutral molecules. In the present paper, molecular mechanics and molecular dynamics simulations were used to investigate the  molecular recognition of bis(amidopyridine)\|linked calix\[4\]arene and a series of aliphatic dicarboxylic acids. The computational results indicate that multiple hydrogen bonds were formed between the amide of host molecule and dicarboxylic acids guest molecules with different chain lengths, the binding capacity increased with the chain length increasing.  The further study results show that average binding energy obtained by molecular dynamic simulation can be in agreement with the experimental binding constants. Meanwhile, the binding energy, which was calculated from the stable conformation gained by dynamic simulation in vacuum and in solution, agrees with the result of the experiment as well.

    Molecular Dynamics Simulation on  Phase Separation of Polymer Blend Systems
    WEI Dong-Shan, LI Yi-Jie, LIAO Qi, JIN Xi-Gao
    2006, 27(1):  156-160. 
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    A molecular dynamics simulation(MD) is performed to study the phase separation of binary symmetric polymer blend systems. The blend systems comprise of two kind of polymers with equal chain length of 20 and total chain number of 1 000. By adjusting chain numbers of polymer A,  a series of volume fractions φ from 0.1 to 0.5 were obtained. Polymer chains were simulated by a coarse-grained bead-spring model. The interaction potential between monomers is purely repulsive Lennard-Jones 12-6 potential and the bond potential between neighbor monomers along the sequence of the chain is FENE potential. The collective structure factor evolving with time,  S(q,t),  is obtained by the fast Fourier transform(FFT) of the concentration fluctuation function. As the phase separation proceeds,  the maximum of the collective structure factor increase with the increase of  time. The average phase domain size R(t) keeps constant at the early stage. At the intermediate stage,  R(t) increase with the increase of  time and a scaling relation  of R(t) vs. t1/3 is observed. At the last stage of the phase separation,  R(t) is time independent again. The time evolution of polymer chain size,  as well as the coordination number of monomer is also investigated during the phase separation. All these indicate that MD simulation is an effective and advantageous method for studying the dynamics of phase separation of polymer blend systems.

    Crystalline Morphologies and Molecular Orientation of Poly(ε-caprolactone) Thin Films
    WANG Zhen, XIE Xu-Ming, YANG Rui, WANG Xiu-Feng
    2006, 27(1):  161-165. 
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    Crystalline morphologies and molecular orientation of poly(ε-caprolactone)(PCL) thin films were investigated by means of combination of microscopic and spectroscopic methods. The PCL films with different thicknesses were prepared on Si and Al substrate by spin-coating. Atomic force microscopy(AFM) observations reveal that for the PCL films with thickness of ca. 200 nm and thicker than it, crystallization occurs preferentially in the form of edge-on lamellar crystals, whereas for thinner films, nucleated edge-on lamellar crystals become to rotate with some tilt angles, and with further decreasing film thickness, lamellae prefer into the plane of the film and grow as flat-on lamellae, which led to a preferred orientation of the PCL main chain axis perpendicular to the surface of the substrate. In addition, there is a dendritic crystal morphology formed when the film thickness is ca. 15 nm. The mean orientation of the polymer molecules in the  films was measured by polarized ATR-FTIR(attenuated total reflection-Fourier transform infrared) spectroscopy, and the results of the polarized ATR-FTIR  correspond to the AFM observations mentioned above. Those phenomena were discussed under a diffusion-limitation crystallization condition in PCL thin films.

    Rheological Behavior of  Phase-separation in PMMA/SMA Blends
    LI Run-Ming, YU Wei, ZHOU Chi-Xin
    2006, 27(1):  166-169. 
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    The dynamic viscoelasticity of poly(methyl methacrylate)(PMMA)/poly(styrene-co-maleic anhydirde)(SMA) blends in the molten state was investigated. The apparent phase separation was marked by a change in slope of the storage modulus and the occurrence of a peak in the loss tangent as a function of temperature. It was found that the apparent phase separation temperatures are strongly dependent on the frequency applied. The phase separation temperature obtained through extrapolation to zero frequency was lower than the cloud point by turbidity method.

    Cure Kinetics Study of the Polymerization of N,N,N′N′-Tetrapropargyl-p,p′-Diamino Diphenyl Methane with 1,1′-Bezidomethyl-4,4′-biphenyl
    LUO Yong-Hong, HU Yan-Hong, WAN Li-Qiang, XUE Lian, ZHOU Wei, HUANG Fa-Rong, SHEN Xue-Ning, QI Hui-Min, DU Lei, CHEN Xiang-Bao
    2006, 27(1):  170-173. 
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    A novel low temperature curing  resin was prepared by the 1,3-dipolar cycloaddition polymerization of N,N,N′,N′-tetrapropargyl-p,p′-diamino diphenyl methane(TPDDM) and 1,1′-bezidomethyl-4,4′-biphenyl(BAMBP) at 70 ℃. The variation of TPDDM with BAMBP of the reactively functional groups during the polymerization was traced by FTIR, the polymerizing reaction of TPDDM with BAMBP and the reaction kinetics were investigated  using FTIR and differential scanning calorimetry(DSC) at a variety of heating rates. The kinetic parameters at different temperatures including the reaction order, activation energy and pre-exponential factor were obtained. The apparent  reaction order n,  activation energy Ea and  pre-exponential factor A calculated from FTIR and DSC data were mutually evidential.

    Effective Interaction Potentials Between Regular Star Polymers by  Self-consistent Field Theory
    XU Jia-Jing, QIU Feng, ZHANG Hong-Dong, YANG Yu-Liang
    2006, 27(1):  174-177. 
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    The effective pair potential and triplet potential of regular star polymers in athermal solvent were calculated by using self-consistent field theory(SCFT), and were compared to the results of scaling arguments and other particle based simulations.  The pair potential is a function of the distance between cores of the two star polymers and their functionality, which has the scaling form: U(d)∝-f3/2ln(d/R).   The triplet potential is attractive when the closest distance among the cores of the three star polymers is less than the effective dimension of the star polymers and its magnitude is only 10% of the pair potential.  Therefore, the pair potential contributes largely to the total interaction potential, which validates the particle based on the simulations where only the pair potential was considered.

    Preparation,  Structure and Properties of Porous Polyimide Films via PAA/PU Alloy
    LIU Jiu-Gui, JIANG Li-Zhong, ZHAN Jia-Yu, WU De-Zhen, JIN Ri-Guang
    2006, 27(1):  178-181. 
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    A new route to porous polyimide films which leads to pore sizes in the nanometer regime was  developed. The polyimide foams were prepared from blending PAA and PU via in situ polymerization(the latter being the disperse phase) by the thermolysis of PU and imidization of PAA, so porous polyimide(PI) films were prepared. The results of  IR, TGA and TEM measurement shows that the optimal thermolysis temperature of PU is 360 ℃, upon a thermal treatment the PU undergoes thermal decomposition, leaving strip nanopores in PI matrix, and the size of pores increases with  increasing PU content. Because of the existence of nanopores, the dielectric constant of PI decreased by a wide margin and was less than 2.0 at PU mass fraction 20%, thus proving that this is an effective means to reduce the dielectric constant of PI, but it cause the decrease of tensile strength and the rise of water absorption.

    Effect of pH of Chitosan Solution on  Properties of Sodium Alginate-Chitosan Microcapsules with Cells
    XU Wei-Ting, LIU Xiu-Dong, LI Xiao-Xia, QI Wen-Tao, REN Dong-Wen, MA Xiao-Jun
    2006, 27(1):  182-186. 
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    Sodium alginate-chitosan(AC) microcapsules are often used as the immobilization carriers for cell culture.  They are composed of porous gel as the core facilitating cell adhesion, and coated with polyelectrolyte complex membrane protecting cells and allowing selective mass transfer.  Therefore, the regulation and control of membrane properties can directly affect the growth and metabolism of cells in microcapsules.  Among many parameters, pH of chitosan solution is the important one.  In this paper, the formation of polyelectrolyte membrane, the degree of complex formation and protein diffusion at different pH values were directly observed in situ by using a confocal laser scanning microscope(CLSM).  The effect of pH on the properties of AC microcapsule membrane was discussed.  The optimal pH was determined in the preparation of AC microcapsules with different cells(animal and microbial cells).  It was demonstrated that the membrane thickness showed “high-low-high” shape, the swelling behavior of microcapsules “low-high-low” shape and the protein diffusion across the membrane “low-high-low” shape as a function of pH, the inflection points all appeared at pH=4.00 and 5.50.  Combining with the sensitivity experiment of different kinds of cells to environment pH, it was suggested that the optimal pH of chitosan solution for AC microencapsulated animal cells was 5.50, AC microencapsulated E.  coli cells 5.00, and AC microencapsulated yeast cells such as saccharomyces cerevisiae(S.  cere.) 4.50, respectively.

    Dynamic Research of Pattern Formation in Two Phase System of Nematic  Liquid Crystal and Hard Particles
    WANG Tao, HONG Ke, ZHANG Hong-Dong, YANG Yu-Liang
    2006, 27(1):  187-191. 
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    In order to inspect the influence of impurities or stuffing on the liquid crystal, numerical results from the modeling and computer simulation of the nematic liquid crystal/hard particles composites pattern formation are presented in this paper. In the simulation, XY model was used to deal with the order parameter and standard cell dynamical  scheme(CDS) was adopted to translate the continuous space into lattice space. The polarizing light pattern from the computer simulation fits the experiment results well, and this gives supports to the model. In order to describe the evolvement of the domain size,  real space correlation function and structure factor were calculated which obey the dynamical scaling with  increasing  nondimensional time t. The defects number also was  checked and it also obeys the dynamical scaling with  decreasing  nondimensional  time t, but  increasing  particle number.  In conclusion,  interactions between  hard particles and liquid crystal do not only decrease the  ordering rate of the order parameter, the grow rate of the domain size and the elimination rate of the defects, but also break the dynamical scaling laws and make the system more complex.

    Controlled/Living Photopolymerization of Methyl Methacrylate Mediated by Bimolecular Systems for HTEMPO/2,2,6,6-Tetramethyl-Piperidinone
    LIU Xiao-Xuan, REN Ya-E, ZHANG Ting, HAN Mei, WU Guang-Guo
    2006, 27(1):  192-195. 
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    Controlled/living photopolymerization of methyl methacrylate(MMA) mediated by bimolecular systems for 4-hydroxy-2,2,6,6-tetramethyl-piperidinyl-1-oxyl(HTEMPO) and 2,2,6,6-tetramethyl-piperidinone(TMPD) was performed at ambient temperature. The effects of HTEMPO, TMPD and their different molar ratio as a mediator and photo-induced oxidization in situ of TMPD in the system were discussed respectively. It is shown that the molecular weight(Mn) of MMA homopolymer increased linearly and the polydispersity index(PDI) decreases with the conversion increasing, even until the conversion up to 80%, mediated by bimolecular system with both HTEMPO and TMPD, which is the characteristic of a controlled/living free radical polymerization. It is found that the obtained MMA homopolymer prepared by the photopolymerization exhibited a narrow molecular weight distribution as was characterized by GPC, the smallest value of PDI is 1.2. The result also shows that the bimolecular systems with HTEMPO/TMPD as a mediator has a  better controlling kinetic performance than that only mediated by HTEMPO under the same condition.

    Conducting PANI/PAN Coaxial Nanofibers with Tuned Wettability
    ZHU Ying, ZHANG Jing-Chang, ZHENG Yong-Mei, ZHAI Jin, JIANG Lei
    2006, 27(1):  196-198. 
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    Abstract By using the template of electrospun polyacrylonitrile (PAN) nanofibers, PANI/PAN nanofibers of conducting forms were prepared in situ chemical polymerization of aniline with the oxidant (NH4)2S2O4.  The SEM indicates that the long nanofibers are randomly distributed in a fibrous mat with a rough surface composed PANI particles whose diameters are about 70-80 nm.  And the nanofibers′  core-shell structure, i.e. coaxial structure, which is consisted of core nanofiber of PAN and shell of PANI, is also displayed clearly by TEM image.  The PANI/PAN coaxial conducting nanofibers were dedoped by dilute ammonia solution and then redoped by PFOS, exhibiting wonderful superhydrophobicity.  The wettability of PANI/PAN coaxial nanofiber can be actively controlled by the doped different organic sulfonic acids on the surface.

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