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    24 June 2004, Volume 25 Issue 6
    Articles
    Hydrometallurgical Preparation of Gold by Electrolysis from Gold-loaded Organic Phase
    ZHOU Wei-Jin, TAO Jia-Xun, LI Wei-Hong, ZHOU Yong, HE Yong-Ke, GAO Hong-Cheng, CHEN Jing, WU Jin-Guang
    2004, 25(6):  991-996. 
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    A new method on direct electrolysis recovery of gold from loaded-metal organic phase with electrolyte aqueous solution together was reported . Electrolysis recovery of gold from the organic phase of extracting Au(CN)-R4N+ by tributyl phosphate(TBP) was studied. Many influences on the recovery of gold were investigated,such as the technical conditions of electrolysis,the concentration of gold,the type and concentration of electrolytes and the effect of the reducing agents. The results show that this method not only omits the traditional procedures such as stripping and reducing and so on,but also obtains adherent sheet gold of high quality with a high recovery rate. And by addtion of small quantity of reducing agent in electrolyte solution,the recovery rate can be further improved. This method was also suitable for the recovery of silver and copper. To prepare silver,the used system was similar to that of preparing gold,but to prepare copper,it should be performed in the system of the Cu-loaded D2EHPA-heptane organic phase with aqueous acidic solution of some electrolytes together.
    Self-assembly Synthesis,Structure Characterization and Antibacterial Activity of Complexes (ABOB)4[H2V10O28]·9H2O and (ABOB)6[V10O28] ·4H2O(ABOB=Moroxydine)
    LIU Shu-Xia, ZHAI Hong-Ju, PENG Jun, LI De-Hui, DAI Zhi-Min, WANG En-Bo, HU Ning-Hai, JIA Heng-Qing
    2004, 25(6):  997-1001. 
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    Two novel complexes(C6H14 N5O)4 [H2V10 O28 ] ·9H2O(1) and (C6H14 N5O)6 [V10 O28 ] ·4H2O(2) were synthesized by the self-assembly of decavanadate and ABOB in aqueous medium at different pH values for the first time. Their structures were determined by means of IR, 51V NMR and X-ray diffraction. Complex 1 crystallizes in the monoclinic system,space group P21/n with a= 1.339 58(8) nm ,b=1.482 62(9) nm,c=1.713 53(14) nm,β=111.450(3)°,V=3.167 5(4) nm3,Z=2,R1=0.050 0,wR2=0.143 4. Complex 2 crystallizes in the monoclinic system,space group P21/n with a=11.698 8(7) nm,b=2.407 94(11) nm,c=1.313 20(10) nm,β=91.635(2)°,V=3.697 8(4) nm3,Z=2,R1=0.039 7,wR2=0.100 8. The X-ray crystallographic study shows that the crystals are constructed by electrostatic forces and hydrogen bond interactions among decavanadate anions,protonated ABOB cations and lattice water molecules. The polyanions,cations and water molecules arrayed in a good order to form 2D layered arrangements along the c axis in complex 1. The antibacterial trial shows that the two complexes show an good antibacterial activity against Staphylococcus aureus,Staphylococcus epidermis,MRSA and MRSE.
    Synthesis,Characterization,Liquid Crystal and Photoluminescent Properties of Surfactant Ruthenium(Ⅱ) Complex
    LI Bin, FU Chun-Yan, SU Zhong-Min, LIU Jing-Fu
    2004, 25(6):  1002-1004. 
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    A new surfactant Ru(Ⅱ) complex [Ru(bpy)2(d19-phen)] Cl2(bpy=2,2′-bipyridine,d19-phen=4,7-dinonadecyl-1,10-phenanthroline) was synthesized and characterized by elemental analysis, mass spectra and 1H NMR. The complex-water mixture displays lyotropic liquid crystalline behaviour. Photophysical properties of the complex was investigated. The complex shows a good luminescence property with a high quantum yield.
    Synthesis and Characterization of ZrW1.7W0.3 O7H0.3(OH)2·2H2O
    ZHAO Huai-Zhou, ZHAO Xin-Hua, HAN Bu-Xing
    2004, 25(6):  1005-1009. 
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    A new sort of heteropoly blue compound,ZrW1.7W0.3O7H0.3(OH)2·2H2O,was synthesized by the acidic-steam hydrothermal process and the microemulsion hydrothermal process. XRD pattern proves that the heteropoly blue compound has the same type of crystal structure as that of ZrMo2O7(OH)2· 2H2O. The rietveld refinement method was used to refine the crystal structure of the heteropoly blue compound. The bond parameters were calculated and the bond valences of atoms were obtained. The EPR result affirmed the subsistence of W Ⅴ ion in the new compound,and the molar ratio of W Ⅴ/W Ⅵ was determined by XPS. Combining with bond valences of atoms and IR spectra analysis,random hydroxylation of W—O3—H0.15 exits in the molecule and the FTIR absorption spectra were assigned.
    Synthesis and Anti-liver Cancer Activity of 5-Fluorouracil Salt of 12-Tungstoboric Acid
    LI Juan, LI Jing, QI Yan-Fei, WANG Hong-Fang, WANG En-Bo, HU Chang-Wen, XU Lin, WU Xin-Yu
    2004, 25(6):  1010-1012. 
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    5-Fluorouracil salt(WBF) of 12-tungstoboric acid with Keggin structure was synthesized and its structure was characterized by IR, 1H NMR, 183 W NMR and elementary analysis. The MTT experimental results show that WBF has a stronger killing ability for liver cancer cells in vitro. The acute toxicity of WBF was carried out. The half toxicity dose LD50 of WBF orally administrated to mice is 1 117.4 mg/kg.
    Preparation and Characterization of NiO Nanofibers via an Electrospinning Technique
    SHAO Chang-Lu, GUAN Hong-Yu, WEN Shang-Bin, CHEN Bin, HAN Dong-Xue, GONG Jian, YANG Xing-Hua, LIU Yi-Chun
    2004, 25(6):  1013-1015. 
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    Thin PVA/nickel acetate composite fibers were prepared by using sol-gel processing and electrospinning technique. After the calcination of the above precursor fibers,NiO nanofibres with a diameter of 50—100 nm could be successfully obtained. The fibers were characterized by TG-DTA, FT-IR,WAXD and SEM respectively. The results showed that the crystalline phase and morphology of NiO fibres were greatly influenced by the calcination temperature.
    Synthesis and Crystal Structure of a 3D Inorganic-Organic Hybrid Compound [Zn3(BTC)2(H2O)3]n with Micropores
    FANG Qian-Rong, ZHU Guang-Shan, XIN Ming-Hong, ZHANG Da-Liang, SHI Xin, WU Gang, TIAN Ge, TANG Lu-Lu, XUE Ming, QIU Shi-Lun
    2004, 25(6):  1016-1018. 
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    The title compound [Zn3(BTC)2(H2O)3]n (BTC=1,3,5-benzenetricarboxylic acid) was synthesized under mild conditions and its crystal structure was determined by single crystal X-ray diffraction. The compound crystallizes in the cubic system and belongs to space group Fm-3m with a=2.662 6(3) nm ,V=18.877(4) nm3,Z=16,Dc=1.51 g/cm3,Mr=664.4,μ=0.198 mm-1 , F(000)=852 ,R=0.062 5,wR=0.129 4. Its structure reveals that the title polymer is composed of dimeric zinc tetracarboxylate units,with a short Zn-Zn internuclear separation of 0.295 0(4) nm. The coordination of BTC ligands with Zn ions forms a 3D infinite framework with about 1.117 4 nm×1.327 4 nm pores along the [001],[100] and [010] direction.
    Determination of E3 in Serum by EIA with Biotin-Avidin Amplification System
    ZHAO Jin-Fu, WANG Yong-Cheng, MI Jian-Qiu, CHANG Wen-Bao
    2004, 25(6):  1019-1022. 
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    The complex of Estriol and Biotin(E3-Biotin) was prepared by a simple procedure. E3-Biotin and horseradish peroxidase-labelled avidin(HRP-Avidin) were regarded as a probe in enzyme immunoassay(EIA). A sensitive EIA was developed and applied to determining E3 in serum. The unspecific adsorption of HRP-Avidin was inhibited by adding the calf serum into enzyme buffer. The experimental results indicated that the higher sensitivity and better stability and repeatability were achieved without any influence from the unspecific adsorption. The calibration curve covered a range from 0.1 to 10 ng/mL,and the limit of detection was 0.06 ng/mL(n=10,3σ/N).
    Application of Independent Component Analysis to the IR spectra Analysis
    BI Xian, LI Tong-Hua, WU Liang
    2004, 25(6):  1023-1027. 
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    A new method for separating the IR spectra based on the Independent Component Analysis(ICA) is presented. The main advantage of this method is that it can be used to separate the spectra of the independent components from the mixed spectra. The separation is a blind source separation,since the independent components in the mixtures was unknown. ICA was used to process the mixed system of {n-hexyl} alcohol,acetone and n-butyl alcohol in this study. We also discussed the effect of various preprocessing methods on the result of ICA and developed the ICA algorithm by adding PCA in front of ICA.
    Preparation of Molecular Imprinting Sol-gel Nanotubes Membrane and Its Application to Biochemical Separations
    ZHANG Shu-Qiong, YANG Huang-Hao, ZHUANG Zhi-Xia, WANG Xiao-Ru
    2004, 25(6):  1028-1030. 
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    Molecular imprinting has become a powerful method for the preparation of robust materials that have the ability to recognize a specific chemical species. The stability,ease of preparation and low cost of these materials have led to their assessment as substitutes for antibodies or enzymes in chemical sensors,catalysis and separations. The present techniques used to prepare molecular imprinting materials most often result in materials exhibiting a high affinity and selectivity but low capacity and poor site accessibility of the target molecules. In this study,we report a simple procedure for applying molecular imprinting functional groups to the inner surfaces of the AAO template-synthesized sol-gel nanotubes for biochemical separation of estrone. Using of nanotubes as the imprinted materials has the advantage of high affinity,selectivity,capacity and site accessibility for the target molecules. And it is important to emphasize that template route can be used to prepare imprinted nanotubes of nearly any materials.
    Enantioseparation of 3-Substituted Isoindolin-1-ones by HPLC
    RUAN Yuan-Ping, XU Xiu-Qing, HE Ming-Zhu, ZHOU Xiang, HUANG Pei-Qiang
    2004, 25(6):  1031-1033. 
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    The enantioseparation of 3-alkyl-isoindolin-1-ones(1—9) and 3-alkyl-3-hydroxy-isoindolin-1-ones(10—14)(R=Me,Et,n-Pr,n-Bu,n-C5H11 ,n-C7H15 ,i-Bu,Ph and Bn),as well as 3-n-heptyl-2-[2-hydroxy-1-phenylethyl]-isoindolin-1-one(15) by HPLC using (S)-tert-leucine and (S)-1-α-NEA as a chiral stationary phase,and 1%—6%(volume fraction) 2-propanol or ethanol in hexane as the mobile phase was studied. The effect of content of polar solvent in mobile phase on the enantioseparation was discussed. The effects of 3-substituents on retention factor and chiral recognition were studied. For the majority of racemates(1—14),a baseline separation could be obtained. For racemate(15),the elution orders are (3R,1′R)/(3S,1′S) then (3R,1′S)/(3S,1′R) with n-hexane/2-propanol(volume ratio 99∶1) as a mobile phase and the resolutions are 1.44 and 5.58,respectively.
    Molecular Imprinting Mechanism Study with Benzoic Acid and Ethyl Benzoate Analogues as Templates
    YANG Min-Li, LI Yuan-Zong
    2004, 25(6):  1034-1036. 
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    Molecularly imprinted polymers(MIPs) were synthesized by using derivatives of benzoic acid and ethyl benzoate as the templates. The paper aims at studying the effect of the different functional groups on the imprinting process by summarizing the chromatographic data,and the relationship between the imprinting interaction and the solvents used during the polymerization was discussed. The experimental results show that the structure of the template plays a decisive role in imprinting effect,and imprintogenicity can be improved by changing solvent and monomer for the template. In addition,when carboxy group is replaced by ester group,the templates would lose their imprinting effect completely in acetonitrile;if chloroform is used as porogen,the imprintogenicity of ethyl p-aminobenzoate and ethyl p-hydroxybenzoate will evidently be improved. The result indicates that the solvents used during the polymerization have a great influence on whether the groups of the template can act as effective imprinting groups. Therefore,the solvents should be taken into account in designing the experiments or in theoretical prediction of the imprinting effect of the templates.
    A Rapid Separation and Determination of Amino Acids by Capillary Electrophoresis with a High Frequency Conductivity Detector
    ZHAI Hai-Yun, CAI Pei-Xiang, CHEN Zuan-Guang, LI Guan-Hong, YE Xin, MO Jin-Yuan
    2004, 25(6):  1037-1039. 
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    A reversed capillary electrophoresis with contactless high frequency conductivity detection method to determine amino acids mixture was described. In this study,cetyltrimethylammonium bromide(CTAB) was used to reverse electro-osmotic flow in order to shorten the analysis time. β-CD was added to optimize the separation further. The effects of separation potential,concentration of CTAB,buffer electrolyte and β-CD etc. were researched and the best analysis conditions were obtained. Ten kinds of amino acids were separated and detected directly in running medium of 15.0 mmol/L diethylamine/0.10 mmol/L H3BO3/0.10 mmol/L CTAB/0.25 mmol/L β-CD(pH=11.0) at the separation potential of -20 kV within 7 min. The correlation coefficients of amino acids are 0.991—0.999 in the linear range of 1.00×10-6 —1.00×10-3 mol/L,the limit of detection are 0.17—0.94 μmol/L(S/N=3).
    Resonance Rayleigh Scattering Spectra of Interaction of Trace Amounts of Cationic Surfactants with Some Acidic Triphenylmethane Dyes and Their Analytical Applications
    YANG Zhuo, LIU Shao-Pu, LIU Zhong-Fang, HU Xiao-Li
    2004, 25(6):  1040-1042. 
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    In a thin HCl medium,RRS intensities of an alone CS or acidic triphenylmethane dye (TPMD) are very week. However,when TPMD reacts with a CS to form an ion-associate,the RRS intensity is enhanced greatly and a new RRS spectrum appears. The spectral characteristics of the RRS for the ion-associates and the optimum conditions for the reactions are investigated. The intensity of RRS is directly proportional to the mass concentration of CS in the range of 0—3.5 or 0—5.0 μg/mL. The method has a high sensitivity for the determination of CS,their detection limits are between 3.1 and 9.8 ng/mL depending on the different CS. In this case,most metal and non-metal ions do not interfere,so that the method has a good selectivity. Therefore,a sensitive,selective,simple and rapid method for the determination of CS by RRS is developed.
    Infrared Spectroscopy Studies of Nano-graphite Synthesized by Explosive Detonation
    WEN Chao, JIN Zhi-Hao, GUAN Jin-Qing, SUN De-Yu, LI Xun, LIU Xiao-Xin, LIN Ying-Rui, TANG Shi-Ying, ZHOU Gang, LIN Jun-De
    2004, 25(6):  1043-1045. 
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    The nano-graphite powder was prepared by means of detonating of pure TNT(trinitrotoluene) explosives in a steel chamber. X-ray diffraction(XRD) and IR results indicate that the black solid powder which collected from the wall and the bottom of the chamber after the detonation has graphite structure and the average size of the particles of graphite is 1.86—2.58 nm. In the FTIR spectrum,there are two characteristic absorption peaks of graphite at 1 561 and 1 233 cm-1 and two antisymmetrical stretch vibration absorption peaks of CH2 at 2 923 and 2 853 cm-1 ,and one flexural vibration absorption peak of CH2 at 1 467 cm-1 . The vibration absorption peaks of CH2 disappeared when the nano-graphite is treated by acid. From the XRD spectrum and the mechanism of forming nano-graphite,the reason of the vibration absorption peaks of CH2 existing in the FTIR of nano-graphite was discussed.
    Simulation,Construction and Expression of the Recombinant dscuPA with Thrombolytic and Antithrombus Bifunction
    ZHANG Lei-Liang, JIAO Jian-Wei, SHAO Kai-Feng, YU Mei-Min, RU Bing-Gen
    2004, 25(6):  1046-1050. 
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    A recombinant chimeric plasminogen activator(dscuPA) was constructed, consisting of the decorsin(platelet aggregation inhibitor) and a low molecular mass(32 000) single-chain urokinase(scuPA-32k,comprising Leu144 through Leu 411). The structure of the designed protein was predicted and simulated. The recombinant protein was produced in E. Coli after IPTG induction and exited in inclusion body. After refolded in vitro,the chimeric protein was purified by chromatography. The special activity of the chimera was 92 000 IU/mg detected by fibrin plate determination. The chimera could activate plasminogen following Michaelis-Menten kinetics with Km=1.36 μmol/L and kcat=0.002 8 s-1,corresponding to that of scuPA. It was also shown that chimera inhibited ADP-induced platelet aggregation in a concentration dependent manner. These results showed that the chimeric protein not only had high thrombolytic activity but also had anti-thrombus function.
    Improvement of Total Synthesis of (±)-Hinesol and (±)-Agarospirol
    WANG Jin-Jun, MORI Akiro, HATSUI Toshihide, TAKESHITA Hitoshi
    2004, 25(6):  1051-1055. 
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    The basic framework of spiro [4,5] decane was constructed by photo-cycloaddition of methyl 2,4-dioxopentanoate(1) to 1,5-dimethyl-6-methylenecyclohexene(2) and retro-benzilic acid rearrangement of the proto-[2+ 2]photocycloadduction to afford a spirocyclic compounds(3) having vetivan structure. The carbon-carbon double bond of the five-membered ring in compound 3 was selectively reduced by using zinc dust to give spirocyclic diketone 4. The exocyclic carbonyl group was protected and the cyclic ketone group was converted into methylene group to give important vetivan-type precursor 6. The title compound 11 as a mixture was obtained by Grignard reaction with methyl magnesium bromide. The phenylurethanes isomers 12,derived from compound 11 by reaction of hydroxyl group with phenylisocyonate,was isolated from each other. (±)-Hinesol and (±)-agarospirol were synthesized by reduction with lithium aluminum finally. This method shortened the synthetic line,simplified empirical processes and raised the overall yield in comparison with our preceding papers.
    Studies on Adsorption Performance of Affinity Adsorbent for Bacterial Endotoxins
    FANG Hui, WEI Jiao, YU Yao-Ting
    2004, 25(6):  1056-1059. 
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    Bacterial endotoxins(ET) are recognized as the principal mediators in endotoxin shock and multiple organ failure(MOF). Removal of ET in blood by hemoperfusion is one of the effective methods to remove the pathogenic toxin. In the present study,8 amino acids and a poly-L-Lys immobilized on cellulose beads were used in static adsorption experiments to adsorb ET in water solution. Adsorption capacity,adsorption isotherm and affinity mechanism of immobilized amino acid on adsorbents were investigated. The experimental results show that the ligands,Arg and Lys have the highest adsorption capacity which are 182.0 and 160.0 pg/mL gel in 100.0 pg/mL ET solution respectively. Adsorption isotherm of Lys ligand shows that the adsorption amounts of ET increased linearly with increased ET concentrations which shows a good adsorption capacity. The Lys immobilized adsorbent showed to have a high potential for clinical application in endotoxin removal from patients.
    Preparation,Identification and Properties of [B10Glu,B24-Asp-B25] Human Insulin Analogues
    HUAI Wen-Hui, SUN Ting-Wan, YU Mei-Min, RU Bing-Gen
    2004, 25(6):  1060-1064. 
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    Diabetes mellitus is a kind of serious endocrinopathy and insulin is the most effective medicine for the treatment of diabetes. The effective form of insulin when used as medicine is monomer. However,normal insulin usually forms polymers because of its high self-association,which makes it lag in the regulation of glucose level in blood. So it is necessary to develop monomeric insulin analogues. Research on the structure and function of insulin indicates that the interaction between the two insulin molecules of dimer insulin exists mainly between the two β-sheets of C terminus of B chains. There is a strong hydrophobic interaction between aromatic rings of B24,B25,B26 residues. The hydrophobic interaction is crucial for the formation of insulin dimer. B10 His residue is very important for the formation of hexamer. Based on these points,mutations were introduced to the interaction surface,expecting to get monomeric insulin with a low self-association. A mutant gene was constructed through asymmetric PCR. B10His residue was replaced with Glu and Asp was inserted between B24 and B25 residues. The gene was cloned into pBV220,which is a heat-inducing expression vector. The gene was expressed in E.Coli DH5α with a high level. Protein was purified through Sephacyl S-100 after denature and refolding. The proinsulin analogue was digested by trypsin and carboxypeptidase B,the product of which was purified through DEAE Sepharose and RP-HPLC. Protein identities were confirmed by MALDI-TOF mass spectrometry. Purified insulin analogue was obtained. The self-association of the insulin analogue was studied through analytical size exclusive chromatography with Superdex 75 column. The result showed an lower self-association than human insulin obviously. Conformation changes were studied through circular dichoism,results of which also showed the insulin analogue had a low self-association. These results indicated this insulin analogue had a strong monomeric property. B10His was replaced with Glu,and hexamer could not form. The acidic residue Asp was inserted between B24 and B25.It could destroy the hydrophobic interaction between molecules. These two factors could weaken the self-association of insulin greatly. The biological activity of the human insulin analogue was also studied in vitro. The relative activity of RIA was {73.7%}. The relative activity of RBA was 146%. The analogue retained high activities in vitro. It suggested that [B10Glu,B24-Asp-B25] human insulin could be a potential drug for the treatment of diabetes.
    A Pair of New Enantiomeric Amides with DNA-cleaving Function
    ZHU Chang-Jin, LU Yang, DU Hai-Lian, JIANG Yu-Yang, ZHAO Yu-Fen
    2004, 25(6):  1065-1068. 
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    A number of small molecules have been shown to hydrolyze RNA as probes in RNA structure studies but very few reports have been found that small molecules can hydrolyze DNA. Previously we found that ser-his dipeptide could cut DNA probably via a hydrolytic mechanism,and also showed protein-cleaving activity. We have focused on developing additional small molecules with DNA cleavage activity and studying their mechanism in the cleavage. In the present study,we designed a pair of new enantiomeric serine/histamine amides,L-Ser-Hism and D-Ser-Hism. These two amides were synthesized by coupling of L- and D-serine with histamine,respectively,using the common DCC peptide synthesis method. Their function was assessed by the electrophoresis of DNA products,which were produced from the incubation of the amides with DNA. It was found that both of the amides were capable of cleaving DNA significantly at optimal pH=6.0——6.5,and that the isomer L-Ser-Hism showed a stronger cleavage function than the other isomer D-Ser-Hism. However,they could not cleave the protein BSA when the amides were tested in the protein cleavage experiment. These findings suggest the preferential DNA cleavage function of the amides.
    A Novel Synthesis of Optically Pure trans-(+)-Sobrerol
    WANG Qiu-An, LUO Jun-Xia, LIAO Tou-Gen
    2004, 25(6):  1069-1072. 
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    A novel and highly efficient synthesis of optically pure trans-(+)-sobrerol,starting from methyl 3,5-dihydroxy-4-methyl benzoate(2) in 7 steps with overall yield 27%,was reported. The key intermediate(+)-5 was prepared in remarkably high yield by lipase__catalyzed asymmetrization of 4. A critical step to stereoselectively inverse the configuration of(+)-6 was realized under Mistunobu conditions. The structures of all the compounds were confirmed by IR,MS and NMR spectra.
    Protection of Small Molecule Corn Peptide Leu-Asp-Tyr-Glu from Mitochondria Against Oxidative Damage
    XU Li, LI Xiang-Lu, HUANG Yi-Bing, WU Xiao-Xia, HOU Rui-Zhen, WANG Hua, WANG Na, ZHANG Xue-Zhong
    2004, 25(6):  1073-1075. 
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    A small molecule peptide Leu-Asp-Tyr-Glu(LDYE) prepared from the enzymatic hydrolysate of zein was tested for its anti-oxidative activities. The effects of LDYE on the turgidity of mitochondria,the fluidity of membrane,the activity of cytochrome C oxidase and ATPase at subcellular level were investigated by using H2O2/Fe2+-induced mitochondria damage model system. It was found that the small peptide exhibited an obvious ability of removing free radicals and protecting the mitochondria from damage by oxidation.
    Preparation and Characterization of Cu Doped TiO2 Nanoparticles and Their Photocatalytic Activity
    XIN Bai-Fu, JING Li-Qiang, FU Hong-Gang, SUN Zhi-Hua, REN Zhi-Yu, WANG Bai-Qi, CAI Wei-Min
    2004, 25(6):  1076-1080. 
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    In this work,pure and Cu doped TiO2 nanoparticles with different molar fractions of Cu were prepared by a sol-gel process,and were characterized by means of XRD,TG-DTA,XPS,DRS and FS spectra. We mainly investigated the effects of calcining temperature and Cu content on the properties and the photocatalytic activity of as-prepared TiO2 samples,and also discussed the relationships between FS spectra and photocatalytic activity as well as the mechanisms of Cu doping on TiO2 phase transformation. The results showed that Cu2+ dopant greatly promoted TiO2 phase transformation,and made the optic response range of TiO2 nanoparticles expand to the visual light,Cu dopant did not give rise to new FS phenomena,but it could make the FS intensity decrease with an appropriate Cu content. Moreover,in the experiment of photocatalytic degradation phenol,Cu doped TiO2 nanoparticles calcined at 500 ℃ exhibited a higher photocatalytic activity,corresponding to the characterization results. The order of photocatalytic activity of Cu doped TiO2 samples with different molar fractions of Cu was opposite to the orders of their PL intensity,namely,the weaker the PL intensity,the higher the photocatalytic activity. This could be explained by the points that the dopant Cu2+ could capture photoinduced electrons not only to make the FS intensity decrease during the process of photoluminescence but also to promote the oxidation of organic pollutants during the process of photocatalytic reaction.
    Theoretical Studies on Dipole Moment Surface and Ro-vibrational Transition Intensities of He-N2O
    ZHOU Yan-Zi, ZHU Hua, XIE Dai-Qian, YAN Guo-Sen
    2004, 25(6):  1081-1084. 
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    The intermolecular potential energy surface and dipole moment surface for He-N2O have been calculated by using the forth-order Moller-Plesset(MP4) perturbation theory with a large basis set (AVTZ) augmenting with the midpoint bond function set 3s3p2d. The two-dimensional discrete variable representation method was employed to calculate the ro-vibrational energy level for 4He-N2O and 3He-N2O. The transiton intensities of the rotational transitions in the ν3 region of N2O for the ground vibrational state have been calculated and compared with the observed results.
    Studies on the Pseudo-ternary-component Phase Diagrams of CTAB/ n-Butanol-n-octane-water or Brine Systems and Electrical Conduction of Its Microemulsion Microstructure
    LUO Jing-Qing, ZHAO Xin-Hua, ZHOU Gu
    2004, 25(6):  1085-1089. 
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    The phase diagrams of the pseudo-ternary-component of CTAB/n-butanol-n-octane-water or brine[Al(NO33 or Na2WO4] systems were studied by dilution method. The microstructures of microemulsions were determined through conductance technique. Via percolation theory and electrolyte theory the single-phase regions of the microemulsions were delimited as W/O,O/W and bicontinuous microemulsion domains. In the W/O microemulsion regions we got a small domains(L′) in which the dispersed entities are of spherical form.
    Effect of Pretreatment Conditions on the Activity of Catalytic Reduction of NO over Pt/Al2O3 Catalyst
    WANG Jing, FU Li-Xin, LI Jun-Hua
    2004, 25(6):  1090-1095. 
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    Pt/Al2O3 catalysts were prepared by impregnation method in which Pt loading was fixed at mass fraction 0.5%,and the Al2O3 carrier was prepared by sol-gel method. The activity for selective catalytic reduction of nitric oxide by propene in the presence of oxygen over Pt/Al2O3 catalyst was investigated and the bonding state of Pt in the samples pre-treated under different conditions was studied. It has been found that the activity window of the catalyst calcined in H2 is the widest,and it changed little when the calcined temperature increased;the catalyst activity of the catalyst pretreated in O2 at 523 K is the highest,the activity window shifted to a higher temperature when the calcined temperature increased. The reason of the activity difference is explained by the temperature programmed desorption. According to XPS measurements,the main bonding state of platinum supported on Al2O3 is Pt2+ calcined in O2 at 523 K,and Pt0 calcined in N2 and H2 at 523 K,respectively.
    Studies on Bonding Property and Stability of [C(AuPH3m]n+ (m=4—6;n=0—2)
    PAN Qing-Jiang, ZHANG Hong-Xing
    2004, 25(6):  1096-1099. 
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    The ab initio MP2 method was employed to fully optimize the structures of C(AuPH34[1a(C4v );1b(Td)],[C(AuPH35]+[2a(C3h );2b(Cs)] and [C(AuPH36]2+[3a(C2h );3b(C2v)]. The calculated geometry parameters agreed with the experimental values. The natural bond orbitals (NBO) analysis at the second-order perturbation approximation level shows that the Au atom possesses d(sp) hybrid character,in which the (sp) means the mixed orbital character with the s and p orbitals. The interplay between the radial C—Au σ bonding and the tangential Au-Au weak interaction stabilizes the title compounds. Compounds 1a,2 and 3 possess 2 or 3 three-center two-electron bondings,suggesting that it is necessary to adopt a delocalized molecular orbital bonding description to account for their electronic and stereochemical requirements.
    Application of Tree Structured Fingerprint to the Prediction of pKa of Pyridine Derivatives
    QI Yu-Hua, ZHANG Qing-You, LUO Cao-Cao, WANG Jun, XU Lu
    2004, 25(6):  1100-1103. 
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    For the prediction of pKa of pyridine derivatives,the combinations of the parameters by using the method of tree structured fingerprint and the quantum-chemical parameters was performed. The results of the cross-correlation among the selected ten parameters showed that they possessed low correlations. And the results of the cross-validation method indicated that the multiple linear regression model was very steady. Furthermore,the pKa values were estimated by using artificial neural networks.
    Quantum Chemical Study on the Energy Level Structure of Thiophene Oligomers
    YANG Guo-Bo, ZHOU Yin-Hua, TIAN Wen-Jing, ZHOU Xin, PAN Qing-Jiang, REN Ai-Min
    2004, 25(6):  1104-1107. 
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    Thiophene-based monodispersed linear π-conjugated oligomers with a well-defined chemical structure are the subject of considerable current interest related to their potential applications as active material in organic electronics and photonic devices in molecular electronics. In this paper,we have investigated two series of EDOT oligomers,in which EDOT moieties have been inserted either as a median bis-{EDOT} core or and external end groups by quantum chemical calculations. Their absorption spectral peaks,the frontier molecular orbitals HOMO and LUMO were calculated by using the semi-experiential method AM1 and PM3. It is indicated that the changing tendency of the calculated results is in good agreement with the experimental observations.
    Synthesis and Characterization of CdSe Nanoparticle Stabilized by Hexadecyl Amine
    SHAN Gui-Ye, LÜ Qiang, AN Li-Min, WANG Ting-Ting, KONG Xiang-Gui, YANG Wen-Sheng, BAI Yu-Bai, LI Tie-Jin, SUN Jia-Zhong
    2004, 25(6):  1108-1110. 
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    CdSe colloid nanocrystals with a High luminescence quality were synthesized by the reaction of CdO and Se precursors at a high temperature. In this experiment,three kinds of sizes of CdSe nanocrystals were obtained by changing the amount of hexadecyl amine in the system. With TEM,XRD and fluorescence emission spectra,we characterized the morphology,structure and optical quality. The results indicate that hexadecyl amine has so great effect on the size of nanocrystals that the size of CdSe nanocrystal increases with increasing the amount of hexadecyl amine
    Theoretical Study on the Hydrogen Bond Strength in Polypeptide Molecules
    WANG Chang-Sheng, QI Xue-Jie, MA Ying-Ge, YANG Zhong-Zhi
    2004, 25(6):  1111-1114. 
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    The geometrical structures of tetrapeptide,and octapeptide complexes were optimized with B3LYP method. The hydrogen bond strength was studied by using the hydrogen bond acidity. It was concluded that the hydrogen bond has a the biggest hydrogen bond strength in peptide molecules if it has the smallest H…O distance and the largest N—H…O angle. It is intrinsic for the polypeptide to form the hydrogen bond,which has a smaller distance of H…O,a larger angle of N—H…O,and a bigger membered ring. There does exist the cooperativity among the hydrogen bonds in the 310 helix structure of peptides. The more the numbers of the hydrogen bonds in the helix structure,the stronger each hydrogen bond is.
    Photo Stimulated Surface Catalytic Syntheses of Methanol and Hydrogen from Methane and Water over MoO3-TiO2/SiO2
    SANG Li-Xia, ZHONG Shun-He, XIAO Xiu-Fen, WANG Xi-Tao, TAN Jian-Hua, ZHOU Zhi-Quan
    2004, 25(6):  1115-1119. 
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    TiO2/SiO2 were prepared by the chemical modification reaction on SiO2,and MoO3-TiO2/SiO2 were prepared by isovolumetric impregnation of TiO2/SiO2. Based on the characterization of XRD,BET,TPR,UVDRS,IR and TPD,the surface species of supported n-p coupled semiconductors(MoO3-TiO2/SiO2) are well-dispersed,which have the quantum size effects and make the photo absorption threshold blue-shifting. The experiments also confirmed that the incorporation of TiO2 can not only enhance the interaction between MoO3 and supports but also improve photo absorption property. In addition,the reactants CH4 and H2O can be adsorbed and activated effectively. The gas-phase photocatalytic production of CH3OH and H2 from CH4 and H2O was performed in the presence of MoO3-TiO2/SiO2 at 100 ℃ by using a fixed-bed annular photoreactor under UV irradiation,with a selectivity of CH3OH being 85.6%. The “photo-surface-thermal” synergistic action can be formed at the reaction temperature,which accelerated the photocatalytic reaction. And the reaction mechanism was proposed.
    Electrochemical Performance of Carbon Nanotube and Graphite Composite Materials
    ZHOU De-Feng, ZHAO Yan-Ling, MA Yue, HAO Jie, XIE Hai-Ming, WANG Rong-Shun
    2004, 25(6):  1120-1123. 
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    When natural graphite(NG) is doped with different ratios of carbon nanotube(CNT),a composite material formed by nano-C and graphite-C was obtained. The measurements show that the complex with 10% CNT(in mass fraction) possesses the best electrochemical performance. Undergoing charge/discharge cycles for 20 times,the charge capacity of this material is obviously improved,15.9% more than that of pure graphite without CNT. Due to the mid-hollow structure and anti-collapse property for CNT,this composite material would increase charge/discharge capacity and stable cycle property.
    Multi-orientated One-dimensional Small Angle X-ray Scattering Study of Microvoids in Polyacylonitrile-based Carbon Fibers
    HUANG Zu-Fei, WANG Chun-Zhong, WEI Ying-Jin, XU Yue, GAO Zhong-Min, HUA Zhong, CHEN Gang
    2004, 25(6):  1124-1127. 
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    The configuration of the microvoids in polyacrylonitrile(PAN)-based carbon fibers was studied by multi-orientated one-dimensional small angle X-ray scattering. The microvoids show a preferred orientation and have needlelike shape elongating along the fiber axis,and the oriented angle is Φ=14°. the cross-section radius of the microvoids projected onto the fiber cross section is R=1.14 nm and the length projected onto the fiber axis is L=17.98 nm. The method developed in this paper reveals some aspects of the configuration of the microvoids which were only available with two-dimensional small angle X-ray scattering technique such as Φ and L,and can be applied to the characterization of the configuration of the microvoids or the microfibrils in other fiber systems.
    Photogeneration Carriers in Organic Doped Systems
    TIAN Wen-Jing, WANG Huan
    2004, 25(6):  1128-1131. 
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    Stationary photocurrrent in phenyl substituted polyphenylenevinylene (PhPPV) and hexabenzocoronene(HBC) doped by perylenediimide(PDI) in a broad range of PDI mass fractions was investigated by steady state photocurrent measurements and using thin films in a light-emitting devices sandwich structure. It is shown that at and above the moderate mass fractions the yield of the charge photogeneration carriers is almost independent of the system and the mass fractions of dopant. As PDI mass fractions >10%,the photogeneration quantum yield increases by two to three orders of magnitude by comparing with the pure system.
    Investigation of Surface Diffusion and Recombinaton Reaction Kinetics of Adsorbed H-Atoms in the Process of Hydrogen Evolving Reaction(HER) at Au Electrodes
    SU Lei, WU Bing-Liang
    2004, 25(6):  1132-1136. 
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    In the electrochemical devices with the proton exchange membrane(PEM) as the ion conductor the surface diffusion of the adsorbed intermediates impels the catalyst particles which are not in contact with the PEM to take part in the electrode reaction,and thus increases the utilization efficiency of the catalyst. In this paper,a specially designed experimental device based on the planar Au as the working electrode has been used to study the surface diffusion and the recombination reaction of overpotential-deposited(OPD) H-atoms in the process of the HER on the gold surface. In the chronoamperometric experiment,it was observed that the experimental current increases due to the surface diffusion and recombination reaction of the OPD H-atoms on the surface of gold. Under the supposed kinetic model,the numeric analysis has been done,and the surface concentration of the OPD H-atoms as the function of the reaction potential,the surface diffusion coefficient and the kinetic constant of surface recombination reaction were obtained by fitting current obtained experimentally.
    Effect of Ionic Liquid on the Oxidative Esterification From Methacrolein to Methyl Methacrylate
    LI Gui-Hua, ZHANG Suo-Jiang, LI Zeng-Xi, LI Ming-Xiu, ZHANG Xiang-Ping
    2004, 25(6):  1137-1138. 
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    Ionic liquid(IL),[bmim]PF6,was used in the reaction of one-step oxidative esterification from methacrolein to methyl methacrylate. It was found that ionic liquid not only increased the selectivity of methyl methacrylate but also inhibited its polymerization. The selectivity of methyl methacrylate was increased from 45% to 100% with ionic liquid. The experiment results showed that the content of ionic liquid had no effects on the selectivity of methyl methacrylate in a certain range of IL concentration,which indicated that ionic liquid could be used as a potential inhibitor of polymerization.
    ESR Evidence on Light-induced Nitric Oxide Formation in Higher Plant Chloroplasts
    LIU Bin, ZHANG Shu-Xiao, SONG Yu-Guang, NIE Zhou, TIAN Qiu, LIU Yang
    2004, 25(6):  1139-1141. 
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    Spin-trapping ESR method was used to study a novel NO formation pathway in higher plant chloroplasts with Fe3+(MGD)2 as a NO trap. The oxygen evolution complex (OEC) of the chloroplasts was treated with TEMED,and the electron donor DPC was provided to recover the electron transfer chain. Under anaerobic conditions,NO2- was reduced by strongly illuminating chloroplast to form NO. However,when kept in dark or when illuminated without DPC,no NO signal could be detected in the reaction system. The results show that the formation of NO is closely related with the light-induced electron transfer in higher plant chloroplasts.
    Effectof UV Illumination Treatment on Surface Photovoltaic Properties of TiO2 Films
    FENG Wen- Hui, SONG Yan- Lin, WANG De- Jun, ZHAI Jin, JIANG Lei
    2004, 25(6):  1142-1144. 
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    Ti O2 films and N- doped Ti O2 films were prepared by magnetron sputtering methodology.The films were illuminated at365 nm for5— 20 min followed by the measurementof contactangles and surface photovoltage spectroscopy.The results show thatfor n- type Ti O2 film,UV illumination treatment can in- crease the photovoltage,while for p- type Ti O2 film,such treatment can decreases the photovoltage.The photovoltaic changing was explained by Ti— OH group increasing due to photo- induced hydrophility.For n- type Ti O2 film,Ti— OH groups can increase the photo- induced charge separation and thus iucrease the photovoltage;for p- type Ti O2 film,Ti—OH groups decrease the photo- induced charge separation and thus decrease the photovoltage.
    Effect of PPC on the Crystallization Behavior of Poly(β-hydroxybutyrate-co-β-hydroxyvalerate)
    LI Jing, LIU Jing-Jiang
    2004, 25(6):  1145-1148. 
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    The crystallization behavior of PHBV and PHBV/PPC(mass ratio: 30∶70) blend was investigated by DSC and FTIR. The result showed that PHBV and PPC had a certain extent of transesterification reaction in the melt blending process. The certain interaction between the two macromolecules was confirmed by means of FTIR analysis. The fold surface free energy of the developing crystals of PHBV isothermally crystallized from melt decreased,however,the relative degree of crystallization,the linear growth rate of spherulites,equilibrium melting temperature and crystallization capability of PHBV decreased due to the addition of PPC.
    Conductive Performance of Polyethylene/Carbon Black Composites
    SUN Dao-Xing, ZHANG Shu-Sheng, WEI Qing-Li, ZHUANG Xin-Jie
    2004, 25(6):  1149-1152. 
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    The net conductive performance and the reason why this kind of PE/CB conductive composite material has a positive temperature coefficient(PTC) were put forward and validated in this paper,and the influence of the process, temperature,radiation crosslinking etc. on the electric performance of the PTC composites were analyzed.
    Studies on Principle of Room Temperature Resistivity of Polyethylene/Polyacenic Semiconductor Composites
    SUN Hai-Zhu, TONG Cui-Yan, ZHANG Wei, SHAO Chen, ZU Long-Fei, HE Xing-Quan, XIE De-Min
    2004, 25(6):  1153-1155. 
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    A novel conductive material——polyacenic semiconductor (PAS) was used as filler instead of carbon black (CB) to prepare polyethylene (PE)/PAS composites. The percolation threshold of PE/PAS composites was confirmed and the mechanism resulting in the phenomenon of percolation threshold was investigated. The room temperature resistivity of the conductive composites was studied from the content of PAS and heat-treatment method. The experimental results showed that the composites were in their percolation threshold,when the mass fraction of PAS was between 20% and 40%,heat-treatment method could make the crystal of PE and conductive chain complete;PE/PAS composites had a high PTC effect;radiation crosslinking could increase PTC effect and decrease NTC effect of composites.
    Synthesis and Thermal Properties of PEEK-PEDEK Block Copolymers
    WANG Han-Fu, ZHAO Xiao-Gang, LIU Xin-Cai, CHEN Liang, WANG Li-Feng, CHEN Chun-Hai, WU Zhong-Wen
    2004, 25(6):  1156-1159. 
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    A series of PEEK-PEDEK block copolymers were synthesized by one step method. Their crystallization and melting behavior were analyzed by Differential Scanning Calorimeter (DSC) and Wide Angle X-ray Diffraction (WAXD). The results show that the glass transition temperature of the copolymer increases obviously as a result of the introduction of biphenyl (BP) units. With the increasing of BP molar fraction,the melting point presents a down and up trend whereas the lowest melting point turns out at a point where the molar fraction of biphenyl is 20%.
    Function of Potassium in Spinning Process of Spider Nephila
    CHEN Xin, HUANG Yu-Fang, SHAO Zheng-Zhong, HUANG Yao, ZHOU Ping, David P. Knight, Fritz Vollrath
    2004, 25(6):  1160-1163. 
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    The spider dragline silks have attracted many interests for their marvelous comprehensive mechanical properties in the past few decades. However,the application of such an excellent material is extraordinarily restricted due to the difficulty of collection. Therefore,many attempts have been made in order to obtain spider silk fibers,in which the artificial spinning was thought to be most practical. Unfortunately,till now the properties of artificial silk fibers still cannot compare with the natural one. We think the reason for poor artificial silk fibers may be the only consideration of pure silk protein spinning solution and industrial spinning condition in the artificial spinning process. We know the spider spinning process in a bioprocess,therefore we think it is necessary to consider its biological environment. In this article,we found the potassium content was much higher in Nephila dragline silk than in its spinning dope by means of ICP-MS. We also found the addition of KCl into Nephila spidroin solution made it become turbid. The electron microscope observation revealed the nanofibril formation in the solution and the turbidimetry showed the turbidity declined about 1 h later indicating the precipitation of spidroin aggregation from the solution. Moreover,the conformation transition from random coil/helical to β-sheet was monitored with FTIR and Raman spectroscopy when the Nephila spidroin membranes were immersed in KCl solution. In conclusion,all the experimental results suggest that potassium may have a special effect in the spinning process of spider Nephila.
    Microstructure and Aqueous Solution Behavior of Amphiphilic Block Copolymer of Acrylamide-styrene
    GAO Bao-Jiao, XU Ru-Xiu, YU Shi-Kui, XU Li, GE Zhen
    2004, 25(6):  1164-1169. 
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    Three series of the amphiphilic block copolymers of acrylamide(AM) and styrene(St) were prepared in microemulsion medium by using sodium dodecyl sulfate(SDS) as the surfactant. One of the copolymer PAM-b-PSt series had a variation of the amount of the hydrophobic block segments PSt by changing the feed ratio in copolymerization at fixed amount of initiator and at constant level of St/SDS,the second had different lengths of the hydrophobic block section PSt by changing the ratio St/SDS which decides the length of the hydrophobic blocks,under fixed amount of initiator and at constant level of feed ratio of monomers,and the third had a variation of molecular weight by changing the amount of initiator at constant level of feed ratio of monomers and constant level of St/SDS. The hydrophobic associating behavior of amphiphilic block copolymers can be revealed at a macroscopic level by the formation of hydrophobic microdomains in aqueous solution and its surface activity can be displayed by the ability to decrease surface tension of aqueous solution. So the relationship between the microstructue and the hydrophobic associating property and surface activity of the amphiphilic block copolymer PAM-b-PSt was investigated by florescence probe technology and measuring of surface tension of aqueous solution. The experiment results showed that the hydrophobic associating property of PAM-b-PSt was dependent on its microstructue strongly. In aqueous solution,above a critical associating concentration,intermolecular hydrophobic interactions lead to the formation of polymolecular associations and the formation of hydrophobic microdomains. When the content of PSt blocks and molecular weight are constant for copolymers PAM-b-PSt, the hydrophobic associating extent varies with the change of the length of the hydrophobic blocks. The longer the hydrophobic blocks are,the stronger the hydrophobic association degree is. But the length of the hydrophobic blocks does not influence its surface activity nearly. When the length of the hydrophobic blocks and molecular weight are constant,the hydrophobic associating extent varies with the change of the content of PSt blocks,at a appropriate level of the content of PSt in the PAM-b-PSt molecular chains there are the strongest hydrophobic associating effects. When the length and content of the hydrophobic blocks are constant for copolymers PAM-b-PSt,the hydrophobic associating extent does not vary with the change of the molecular weight nearly. But,the molecular weight influences the surface activity of PAM-b-PSt obviously. The lower the molecular weight is,the stronger the surface activity is. Thus after clarifying the relationship between the aqueous solution properties and the microstructue for PAM-b-PSt,it is possible to control its association degree and surface activity for some purpose.
    Synthesis and Characterization of Gradient Copolymer Composed of Styrene and Methyl Methacrylate in Water Dispersion System
    ZHANG Bin, ZHANG Zhao-Bin, WAN Xiao-Long, HU Chun-Pu , YING Sheng-Kang
    2004, 25(6):  1170-1173. 
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    The controllability as well as the monomer reactivity for the atom transfer radical copolymerization of styrene(St) and methyl methacrylate(MMA) in water dispersion system was examined with ethyl 2-bromoisobutyrate as the initiator,CuBr/CuBr2/1,10-phenanthroline as catalyst and sodium laurylsulfonate as surfactant,respectively. The gradient copolymerization of St and MMA was performed in the water dispersion system with continuous addition of the second monomer MMA into the copolymerization system. The experimental results showed that the water dispersion gradient copolymerization proceeded in a living fashion,producing well-defined copolymers with narrow polydispersities and controlled molecular weights. The increase of the cumulative composition and instantaneous composition of MMA unit along the copolymer chain length demonstrated that the gradient copolymer composed of St and MMA was successfully synthesized in such a water dispersion system.
    Rate Retardation in RAFT Polymerization
    LI Li, HE Jun-Po, YANG Yu-Liang
    2004, 25(6):  1174-1176. 
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    Two opposing explanations to significant rate retardation in dithioester-mediated polymerization with reversible addition fragmentation chain transfer process(RAFT),e.g: slow fragmentation of intermediate radicals (Model A),and cross termination between intermediates and growing radicals (Model B),had been proposed by Davis and Monteiro independently. In this paper,a comparison of simulation results of Model A and Model B with experiment results was presented. The simulated results show that the intermediate concentration of Model A is much higher than that of experiments,while Model B gives a rather high polymerization rate than experiments with large concentration of dithioesters. The reaction model was better fitted,in light of kinetics,intermediate concentration and distribution of molecular weight,to experimental data when both cross termination and slow fragmentation were taken into account.
    Synthesis and Thermal Cross-linking of Cross-linkable Poly(ether ether ketone ketione) Alternating Copolymer
    ZHAO Xiao-Gang, BEN Teng, LIU Xin-Cai, GAO Zi-Hong, YANG Xiao-Qing, ZHANG Wan-Jin
    2004, 25(6):  1177-1179. 
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    A novel cross-linkable poly(ether ether ketone ketone) alternating copolymer was synthesized by introducing thio-ether moiety to PEEKK rigid main chain. The copolymer can be processed at 628 K and be cross-linked by annealing at 653 K for 5 h. The cross-linking reaction was caused by the introduced thio-ether moiety instead of the PEEKK moiety. The cross-linked material has better mechanical properties and thermal stability that uncross-liked one. The results will give proof to the further research on controllable cross-linking PEEKK. This material is anticipated to be processed as a thermoplastic material as well as used a as thermosetting material after being cross-linked.
    Synthesis of Tetra(4-diazoniumbenzene)porphyrin and the Self-assembled Film with Poly(styrene sulfonate)
    ZHANG Mao-Feng, JIANG Wei, YANG Zhao-Hui, CAO Wei-Xiao
    2004, 25(6):  1180-1182. 
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    Tetra(4-diazoniumbenzene)porphyrin(TDBP) was synthesized via diazo-reaction of tetra-(4-aminobenzene)porphyrin(TABP). From the analysis results of MALDI-TOF mass spectroscopy and FTIR,it was confirmed that the synthesized porphyrin derivative mainly consists of tetra(4-diazoniumbenzene) porphyrin with trace tri- and di-substituted compounds. The self-assembly of TDBP with poly(styrene sulfonate)(PSS) was carried out and a novel TDBP/PSS multilayer ultrathin film on silicon substrate was obtained. The self-assembled film is very sensitive to heat and light,after heating or irradiation of UV light,the thin film becomes very stable towards polar solvents such as DMF. The coupling reaction of TDBP with phenol and the thermal stability of TDBP were also investigated preliminary.
    Preparation of a New Adsorbent for Removal of Low Density Lipoprotein
    FU Guo-Qi, CHEN Xin-Fu, YUAN Zhi, LIU Bin, SHEN Bin, HE Bing-Lin
    2004, 25(6):  1183-1185. 
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    On the basis of low density lipoprotein (LDL) adsorption on matrix-bound tryptophan,a new LDL adsorbent was prepared with indole-3-acetic acid (IAA) as a ligand,which had indole group in its chemical structure just as tryptophan. Macroporous polyvinyl alcohol (PVA) beads were obtained by suspension copolymerization of vinyl acetate and triallyl isocyanurate in the presence of porogen,followed by subsequent alcoholysis step. The PVA beads were allowed to react with epichlorohydrin,and the thus obtained epoxidized beads were then reacted with several polyamines to introduce space arms with different lengths. IAA was then coupled to the spacer-attaching beads by using DCC/HOBt method employed usually in polypeptide synthesis. The primary in vitro adsorption tests show that the resultant adsorbents provide a satisfactory binding capacity for LDL,and manifest much larger capacity than the adsorbent prepared by direct immobilization of tryptophan on the epoxy-activated PVA beads. This proves that indole groups do play an important part in binding LDL.
    Modification of Kerner-Nielson Equation and Correlation Between Electrical Percolation and Viscoelastic Percolation in CB/HDPEConductive Composites
    ZHENG Qiang, WU Gang, SHEN Lie, SONG Yi-Hu
    2004, 25(6):  1186-1188. 
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    The study on the correlation between electrical percolation and viscoelastic percolation for carbon black(CB) filled high-density polyethylene(HDPE)conductive composites was carried out through examining the filler volume fraction dependence of the volume resistivity(ρ) and normalized dynamic storage modulus,G'c/G'p,in which G'c,G'p are dynamic storage modulus of the composites and the matrix respectively. The results revealed that the critical filler volume fraction of viscoelastic percolation approached the lower threshold(φ1) of the electrical percolation,indicating an insulator-semiconductor change corresponding to the beginning of network structure formation. Substituting K for A,a modified Kerner-Nielson equation was obtained and used to analyze the formation of network structure. It is suggested that parameter K is associated with CB volume fraction.