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    24 July 2002, Volume 23 Issue 7
    Articles
    Studies on the Phase Diagram of CsCl-C2H5OH-H2O Ternary System at 30, 40 and 50℃
    HU Man-Cheng, MENG Mei, GAO Shi-Yang, LIU Zhi-Hong, XIA Shu-Ping
    2002, 23(7):  1219-1222. 
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    The isothermal solubility of CsCl-C2H5OH-H2Oternary system in the range of whole temperature was determined and the phase diagram was constructed. The CsCl C2H5OH H2Oternary system at 30, 40 and 50℃ appeared in two liquid phases, alcoholic phase and water phase, while there was only one phase in the CsCl C2H5OH H2Oternary system at 20 ℃. By means of the experiment the critical temperature that appeared in two liquid phases was gained. The equilibrium solid phase is CsCl.
    Synthesis and Characterization of β-PbO2Nanorods and Pb3O4Nanocrystallites
    ZHUANG Jing, DENG Zhao-Xiang, LIANG Jia-He, LI Ya-Dong
    2002, 23(7):  1223-1226. 
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    Phase pure β-PbO2nanorods with diameter of 10-20 nm and length up to 400 nm with an aspect ratio >20 were synthesized through direct oxidation of Pb(Ac)2by NaClOunder alkaline conditions. The obtained β-PbO2nanorods were then decomposed at 420 ℃ to produce Pb3O4nanocrystals with crystallite size ~20 nm. The reaction conditions were optimized on the basis of detailed investigations of the influences of reaction temperature, time, concentraion of NaClO, and pHon the products. Powder X-ray diffraction(XRD) and transmission electron microscope were employed for the characterization of the structure, compositions and morphology of the obtained nanocrystalline products.
    Electrolyte and Electrode Materials of Intermedium-temperature SOFC Prepared by Glycine-nitrate Process
    JI Yuan, LIU Jiang, HE Tian-Min, CONG Li-Gong, SU Wen-Hui
    2002, 23(7):  1227-1230. 
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    By using a new combustion synthesis method, the glycine nitrate process, all the nano-size materials were prepared for a single solid oxide fuel cell(SOFC), in which(CeO2) x (SmO1.5)1-x (x=0.9, 0.85, 0.8) were used as the electrolytes, La0.6Sr0.4Fe0.8Co0.2O3with 50% samaria doped ceria(SDC) was selected as the cathode material, and a SDC-NiO-Ni composite powder was used as the anode material. In this study, the performance of the SOFCwas obtained up to 750 ℃, the maximum power density of 0.104 W/cm2and a short circuit current density of 500 mA/cm2of the cell was achieved at 750 ℃ by using (CeO2)0.9(SmO1.5)0.1electrolyte. The inferior SOFCperformance of the (CeO2)0.8(SmO1.5)0.2electrolyte was due to the physical discontinuity at the clearly grain boundary and could effectively introduce barriers to ionic conduction in reducing atmosphere, while the (CeO2)0.9(SmO1.5)0.1electrolyte′s boundary tends to be merged.
    Synthesis and Properties of [2-(2-Hydroxyphenyl)iminomethyl- [JZ]benzenethiolato(2-)-N,O,S](2-methoxy-(2-methoxy-carbonylethyl-C,O)tin Chloride
    TIAN Lai-Jin, ZHOU Zheng-Yu
    2002, 23(7):  1231-1235. 
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    The title complex, [2-(2-hydroxyphenyl)iminomethyl benzenethiolato(2-)-N, O, S] (2-methoxycarbonylethyl-C, O) tin chloride, CH3OCOCH2CH2SnClL(L=2-SC6H4CHN=C6H4O2), was synthesized by the reaction of 2 methoxycarbonylethyltin trichloride with N (2 hydroxy phenyl)thiosalicylideneimine. This complex reacted with neutral monodentate ligands such as dimethylsulfoxide(DMSO) and hexamethylphosphoramide(HMPA) to form the mixed ligand complexes, CH3OCOCH2CH2SnClLL′(L′=DMSO, HMPA), and also readily underwent transesterification with alcohols to produce the corresponding2alkoxycarbonylethyltin analogues, ROCOCH2CH2SnClL. These complexes were characterized by means of elemental analysis, IRand 1H NMRspectra. The crystal structure for the title complex was determined by X-ray diffraction analysis. The crystal belongs to triclinic system, space group P1with cell parameters α=0.8704(2) nm, b=0.9393(3) nm, c=1.4511(3) nm, α=98.05(3)°, β=103.03(3)°, γ=6.99(3)°, V=1.1299(4) nm3, Z=2, Dc=1.378 g/cm3, F (000)=524. In this compound, the tin atom adopts a distorted octahedral geometry via intramolecular carbonyl oxygen atom and the sulfur, nitrogen and oxygen atoms of the chelating ligand Lto tin coordination.
    Studies on the Polythermal Solubility of System Na2B4O7- Na2CO3-NaHCO3-NaBO2-H2O at0-45 ℃
    ZHANG Feng-Xing, YANG Qin, LI Jun, WANG Zhen-Jun, LI Heng-Xin
    2002, 23(7):  1236-1240. 
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    The isothermal solubilities of the system Na2B 4O7Na2CO3NaHCO3NaBO2H2Ohave been determined at 0, 15, 25, 35 and 45 ℃. On the basis of the isothermal solubilities of the system we constructed its polythermal solubility diagram at 0-45 ℃ by nonlinear fitting method. The formation temperature of Trona is _19.6 ℃, the temperature is lower than 32.7 ℃ when the system Na2B4O7Na2CO3H2Ois a real ternary one. These results have the values of theory and practice for finding the reason of salts mineral bed forming and phase relations of system.
    Hydrothermal Synthesis and Crystal Structure of a Layered Inner-tunnel Compound [(CuI)2(o-phen)2]
    WANG Shu-Tao, WANG En-Bo, LI Yang-Guang, WANG Li-HU Chang-Wen, HU Ning-Hai, JIA Heng-Qing
    2002, 23(7):  1241-1242. 
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    Alayered inner tunnel supramolecular compound 1, [(CuI)2(o-phen)2], was hydrothermally synthesized and structurally characterized by X-ray crystal diffraction. It crystallizes in triclinic system, space group P1 with a=0.7759(2) nm, b=0.9070(2) nm, c=0.91894(10) nm, α=96306(14)°, β = 104.567(16)°, γ=109.421(19)°, V=0.5768(2)nm3, Z=1, R=0.0348, wR=0.0920.
    Syntheses and Structure of α-(+)-Co(en)3V3O6·H2O
    LI Ya-Feng, CUI Wei, ZHU Guang-Shan, SHI Zhan, XU Xian-Zhu, XIAO Feng-Shou, QIU Shi-Lun
    2002, 23(7):  1243-1245. 
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    Co(en)3V3O6·H2Ohas been synthesized by using hydrothermal method and characterized by IR, ICP, XPSand X-ray diffraction analysis. The results of the X-ray diffraction analysis show that structure of Co(en)3(VO3)3·H2Ois orthorhombic with P2(1)2(1)2(1), and the crystal data are a=08192(7) nm, b=1.2639(1) nm, c=1.8048(2) nm, V =1.8688(3) nm3, Z=4, Dc=1.973 g/cm3, F (000)=1124, R 1=0.0407, wR2=0.0949, ( Δ/ρ )max=706 e/nm3and ( Δ/ρ )min =-452 e/nm3. The results of XPSshow that the Co 2+was oxidized to Co 3+(en)3at about pH=7.0 in the aqueous solution.
    A New Technique to Identify Individual Protein in Complex by Microcolumn-HPLC-ESIMS/MS
    ZHANG Su-Yan, WANG Jing, BIAN Li-Ping, XU Yun-Min, WANG Hong-Hai, YANG Peng-Yuan
    2002, 23(7):  1246-1250. 
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    In this work the identification method for protein mixture is reported, in which several proteins were varified by HPLC ESIMS/MSafter the whole complex proteins were directly digested in solution, instead of the routine 2-dimensional gel electrophoresis. The obtained data was then searched against NCBInr database by using MS/MS Ions Search(http://www.matrixscience.com), and a positive result was therefore obtained. With the simulated sequence spectra in database searching, a re identification method was developed for low-score matched protein by sequence-tag technique. As a typical example, Concanavalin A, a less-soluble protein with a low matching score, was also successfully identified, which indicated the great potential of complex digestion in proteomic study.
    Synthesis of a Silica-bonded Bovine Serum Albumin Carbonyl Chiral Stationary Phase for High-performance Liquid Chromatographic Resolution of Enantiomers
    FENG Shun, ZHANG Qiang, ZOU Han-Fa, WANG Ji-De, CHEN Xiao-Ming, ZHANG Zeng-Zi
    2002, 23(7):  1251-1254. 
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    An HPLCchiral stationary phase was synthesized by the in situ covalent immobilization of bovine serum albumin on a aminopropyl silica packed column activated with 1, 1 carbonyldiimidazole in a short time. The effects of mobile phase pHand the content of 1 propanol on k' and α of D, L-trypto-phan were investigated, and the resolution of seven chiral compounds was successfully achieved.
    Graphical Representation and the Similarity of DNA Primary Sequences
    ZHANG Qing-You, XU Lu
    2002, 23(7):  1255-1258. 
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    In this article, graphical representations of DNAprimary sequences were generated. Topological indices and molecular connectivity indices were calculated and used for the comparison of similarities among eight different DNAsegments. The satisfactory results were achieved by this analysis.
    Preparation and Evaluation of 2,4,6-Trinitrophenol-modified Zirconia- Alumina for High Performance Liquid Chromatography and Its Application in the Separation of Fullerenes
    WAN Jian-Di, FENG Yu-Qi, HU Yu-Ling, DA Shi-Lu, WANG Zhong-Hua
    2002, 23(7):  1259-1263. 
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    The zirconia-alumina composites, prepared by means of sol gel process, were modified with 2, 4, 6-trinitrophenol and used as π-acidic stationary phases for the separation of C60and C70. The influence of the mobile phase(toluene-cyclohexane) composition, the column temperature and the different flow rates on the separation of C60and C70was examined. At the same time, the effect of the composites, which were treated and untreated with nitric acid, on the separation was also investigated. The results show that the acid-treated zirconia alumina composite, after being modified with 2, 4, 6-trinitrophenol, exhibits advantage in the separation of C60and C70, and is a potential packing material for separation of fullerenes in preparation scale.
    Surface Modification of Poly(dimethylsiloxane)-fabricated Microfluidic Chip by UVRadiation
    MENG Fei, CHEN Heng-Wu, FANG Qun, ZHU Hai-Lin, FANG Zhao-Lun
    2002, 23(7):  1264-1268. 
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    UVradiation was applied to modify the surface of poly(dimethylsiloxane)(PDMS) fabricated microfluidic replica. After the surface of PDMSwas irradiated by a 6 Wlow pressure mercury lamp, the adhesion between PDMSplates was significantly strengthened, and the PDMSplates were irreversibly sealed when the irradiated surfaces were brought into contact. Hydrophilic behavior of PDMSreplica was improved due to the photochemical reaction induced by UVradiation, resulting in a significant increase in the electroosmotic flow of buffers filled in the microchannels of the chip. Compared with the reported procedures using oxygen plasma pretreatment, the present approach allows one to easily modify the surface of PDMSplates using very simple and cheap equipment available in analytical laboratory.
    A Novel Algorithm for Chemical Factor Analysis Based on Immune Algorithm
    SHAO Xue-Guang, LI Mei-Qing, SHAO Li-Min
    2002, 23(7):  1269-1272. 
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    Based on the principal of immune algorithm, a novel algorithm for chemical factor analysis was proposed, and called immune principal component analysis(IPCA). The basic idea of the proposed method is that it takes a data matrix as antigen, the retrieving eigen vector as antibody, and the orthogonal decomposition of the matrix can be achieved by an iteration of subtracting the principal component represented by the eigen vector, simulating the process of the interaction between antibody and antigen in an immune system. Comparing with the conventional principal component analysis, similar results were obtained. But if we combine the IPCAalgorithm with window factor analysis(WFA) technique, it will be more suitable for resolution of overlapping HPLC-DADsignals than the conventional WFAtechnique. Both simulated and experimental data sets were investigated. Similar results are obtained by the IPCAand PCAfor principal component analysis, but the IPCA-WFAis superior to the conventional WFAin resolution of the multicomponent overlapping HPLC-DADsignals.
    An Investigation on Effect of Desolvation System on Analytical Performance of MPT-AES
    ZHOU Jian-Guang, PENG Zeng-Hui, HUAN Yan-Fu, YU Ai-Min, JIN Qin-Han, ZHOU Xiang, LIU Mei
    2002, 23(7):  1273-1276. 
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    Apneumatic nebulizer(PN) was utilized as a sample introduction device for the microwave plasma torch atomic emission spectrometry(MPT-AES) in an attempt to study the relationship between analytical performance and desolvation system. The desovation system consists of a condenser and a cell with concentrated H2SO4.Some parameters were studied and discussed in this work. The optimized conditions for the MPT-AESwere obtained.
    Studies on Rapid Micro-scale Peptide Mapping Analysis Using a Capillary Micro-reactor
    GUO Zhong, ZHANG Qing-Chun, LEI Zheng-Deng, KONG Liang, MAO Xi-Qin, ZOU Han-Fa
    2002, 23(7):  1277-1280. 
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    Peptide mapping analysis by combining the enzymatic digestion and the MALDI-TOF-MS has emerged as a powerful tool for identification and characterization of protein. We describe a nanoliter micro-reactor prepared with immobilization of enzyme on the porous wall of a capillary. The advantages of the prepared micro-reactor for digestion of the proteins are the elimination of enzyme autolysis and concentration of the micro sample. Horse heart cytochrome c is selected as the target protein for the evaluation of micro reactor, and it is found that about 0.1 picomole of protein analyte could routinely be digested for peptide mapping analysis and even femtomole of protein can be well characterized.
    Compressibility Evaluation of IR Spectra Wavelet Compression
    LI Meng-Long, KANG Bin, QI Hua-Yi, WEN Zhi-Ning
    2002, 23(7):  1281-1284. 
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    The evaluated method for compressibility has been presented when the wavelet compression was applied to IRspectra. Using the method of controlling reconstructed RMSDwe can obtain the compression ratio under the condition of given reconstructed RMSD. With it, we can achieve the greater precision of which relative standard deviation is about eight percent and meet the need of estimating the error of reconstructed spectra and deciding the optimal parameter. In addition, for the different signals, the same wavelet function shows the different compressibilities. So we should select the spectra which are representative when evaluating the compressibility with the method of controlling RMSD.
    Heterolytic (R-H)Bond Dissociation Free Energies in Solution Derived from Electrochemically-monitored Acid-Base Titration(EABT)
    ZENG Qing, HE Jia-Qi, CHENG Jin-Pei
    2002, 23(7):  1285-1290. 
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    An Electrochemically Monitored Acid Base Titration(EABT) method using cyclic voltammetry was established to measure directly the concentration change of all species, then to get the acidic dissociation constants(pKRH ) and bond heterolysis energies(Δ Ghet ) of radical cations. pKRH s of phenothiazine and its analogues in dimethylsulfoxide and acetonitrile were obtained and in good accordance with the pKRH s derived from indirect methods. So, the credence of the present method was tested. Because the exact values of p Ka(or BDE) of the parent molecules and of the anion oxidation potentials needed by indirect methods are not required, the EABTmethod can be applicable to a wide range oforganic systems whose pKRH s may otherwise be difficult to be obtained.
    Studies on the Structural Effects on the Biomimetic Catalytic Properties of New Schiff Base Complexes
    CHEN Xin-Bin, YANG Yan, HU Ling, GUI Ming-De, ZHU Shen-Jie
    2002, 23(7):  1291-1293. 
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    The structural effects on the catalytic properties and the stabilities of new Schiff base complexes M2L{M=Mn(Ⅱ), Fe(Ⅲ)Cl; L=bis[N, N′-alkylene-2, 2′-(phenylmethylene)-bis(3, 4-dimethylpyrrole-5-aldimino)]; alkylene=1, 2-ethylene, 1, 3-propylene, 1, 4 butylene} for the monooxygenation of cyclohexane with PhIOwere studied. The results show that the catalytic activities and the stabilities of these complexes decrease with the increase of the cavity within the molecule of these complexes. We have found that the structural effects in these catalysts on their catalytic properties and stabilities are obvious, and the catalyst with five membered chelating ring is the best in the complexes.
    Effects of Surface Negatively Charged Amino Acid Mutation on Binding Between Cytochrome b5and Cytochrome c
    QIAN Cheng-Ming, WANG Yun-Hua, WANG Wen-Hu, YAO Yong, HU Jun, LU Jun-Xia, XIE Yi, HUANG Zhong-Xian, TANG Wen-Xia
    2002, 23(7):  1294-1298. 
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    The binding between different Cytochrome b5mutants and Cytochrome c has been studied by using of NMRmethod. The result shows that electrostatic effect plays an important role in maintaining the stability and specificity of the complex formed. The differences in association constants demonstrate the electrostatic contributions of Cytochrome b5surface negatively charged residues, which are suggested to be involved in the complex formation in the Brownian dynamics simulations and Salemme models, and to have a significant degree of additivity to the stability of Cyt c-Cyt b5complex, and the contribution of Glu48 is a little higher than that of Glu44. Moreover, our result suggests that the docking geometry obtained from Brownian dynamics simulations by Northrup et al, which was involved in the participation of Glu48, Glu56, Asp60 and heme propionate of Cytochrome b5, do occur in the association between Cytochrome b5and Cytochrome c. The competition between the ferricytochrome b5mutant Ⅰ(E48, E56/A, D60/A) and [Cr(oxalate)3]3-for ferricytochrome c shows that site Ⅲ of Cytochrome c, which is a strong binding site to wild type Cytochrome b5, still binds to the mutant with relatively weaker strength. Our results indicate that there are other docking domains between Cyt b5and Cyt c different from the above mentioned one from Brownian dynamics simulations, at the same time, it also implies that electrostatic interaction on the wild-type Cyt b5and Cyt c interface results in flexible association complexes.
    Synthesis and Anticancer Activities of Novel5-Fluorouracil-1-yl Phosphonotripeptides
    LIU Xue-Jun, CHEN Ru-Yu, YANG Yuan-Yuan
    2002, 23(7):  1299-1303. 
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    Aseries of novel 5-fluorouracil-1-yl phosphonotripetides were synthesized in yield 52%-83% by peptide coupling reaction with DCC/BtOH as the activiating carboxyl group reagent. All products were characterized by 1H NMR, 31P NMR, IRspectra and elemental analyses. The facile method was used to synthesize 5-fluorouracil-1-yl acetic acid(an important intermediate). It was found that two main factors affected the conversion of[(5-fluorouracil-1-yl)methylformyl]aminomethylformic acid to the title compounds. One is the apparent steric hindrance of an α aryl group having a bulky substituent at the ortho position. Another is the electronic effect of the substituent of the α aryl groups. The electron withdrawing groups decrease the nucleophilicity of the amino group. The yields of all products containing the strong electron withdrawing groups were lower than those of other products. The in vitro antitumor activity test showed that some of the synthesized compounds are the potential anticancer agent.
    Three Dimensional Quantitative Structure-activity Relationship of HEPT Analogues as HIV-1 Reverse Transcriptase Inhibitors
    MENG Ge, HE Yan-Ping, CHEN Fen-Er
    2002, 23(7):  1304-1308. 
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    Hydroxyethoxy)methyl]-6-(phenylthio)-thymine(HEPT) and its analogues inhibit HIV-1 reverse transcriptase(RT) selectively. Aseries of HEPTanalogues were analyzed in order to disclose the relationship between their structure and the activity. Thirty two HIV-1RTinhibitors were investigated by means of comparative molecular field analysis(CoMFA). Based upon the active conformation extracted from the HEPT/HIV-1RTcomplex, all the inhibitors were aligned and minimized in energy. Three kinds of CoMFAmodels were established and evaluated. The model(Ⅰ)of steric and electrostatic effects on their activities showed a higher ability to explain and predict the activities of these selective HIV-1 inhibitors than other models, cross-validated RCV2= 0.870, non-cross-validated R2= 0.986, F =294.546, standard error(SE)=0.146. The CoMFAmodel established by examining the steric and electrostatic effect on the structure without considering the effect of π value shows a very high ability to predict the biological activity for testing set compounds and training set compounds and offers an approach to design the new inhibitors. The CoMFAmodel revealed that the suitable length of the 1-side chain is crucial for the antiviral activity. And it also showed that the bulkier group in 5-position and the para-position of the 6-phenylthio group is also benefit for the enhancement of the antiviral activity.
    Synthesis and Crystal Structure of the Polymeric Tribenzyltin 4-Picolinate and Tributyltin 4-Picolinate
    YIN Han-Dong, WANG Chuan-Hua, WANG Yong, MA Chun-Lin
    2002, 23(7):  1309-1313. 
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    Tribenzyltin 4-picolinate(1) and tributyltin 4-picolinate(2) were synthesized by the reaction of sodium 4 picolinate with the tribenzyltin chlorideor tributyltin chloride and were characterized by IR, 1H NMRand MS. Their crystal structures were determined by X-ray single crystal diffraction. The crystal 1 crystallizes in monoclinic, space group P21/n with a=0.96564(8) nm, b=1.64085(14) nm, c= 1.49403(13) nm, β =97.681(2)o, V=2.3460(3) nm3, Z=4, Dc=1.456 g/cm3, and crystal 2 in monoclinic, space group P2 1/c with a=0.96673(14) nm, b=2.3845(4) nm, c=0.97071(14) nm, β =112.463(3)o, V=2.0679(5) nm3, Z=4, Dc=1.324 g/cm3. In crystals 1 and 2, the tin atom rendered five coordinate in trigonal bipyramidal structure by bridging pyridine Natom and the resulted structures are one dimensional infinite chain polymer.
    Synthesis and Resolution of Phenylalanine Analogues Substituted by Halogen
    YU Wen-Sheng, LIANG Yuan-Jun, LIU Ke-Liang, ZHAO Yu-Fen
    2002, 23(7):  1314-1317. 
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    Five kinds of racemic ring-modified phenylalanines were synthesized by using aniline derivatives as the raw materials and further characterized with routine analysis. Most of the amino acids were resolved with chymotrypsin or subtilisin and some protected forms of the amino acids were obtained. The possible mechanism of the method for the relatively large scale synthesis was discussed. These unusual amino acids were used as the building blocks for peptide based antagonists. It had latent investigation values that the physicochemical properties and metabolism behavior in vivo of the peptide containing the amino acids were changed.
    Preparation of Chiral Aminodiols and Their Applications in the Catalytic Enantioselective Addition of Diethylzinc to Aldehydes
    XU Qian-Yong, WU Tong-Xing, PAN Xin-Fu
    2002, 23(7):  1318-1320. 
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    Four new chiral aminodiols 1-4, which were prepared from methyl L-proline in 2 steps, were applied in the enantioselective addition of diethylzinc to benzaldehyde. The results indicated that the enantioselectivities enhance with increasing the bulkiness of substituents on chiral ligands and with chiral ligand 4 giving the best result. When ligand 4 was used to catalyze the enantioselective addition of diethylzinc to aromatic aldehydes, the substituents affect the enantioselectivities slightly and 1-naphthaldehyde gives the best enantiomeric excess(up to 75.3% ). On the other hand, 4-(dimethylamino)benzaldehyde gives a low enantiomeric excess, which may most likely arise from a non steroselective ethyl transfer to aldehyde promoted by zinc coordination of amino group. For aliphatic aldehydes, poor enantiomeric excesses are generally given.
    Preparation and Molecular Structure of Pyrrolinenitroxide Radical Urea
    CHEN Shao-Yuan, NIE Jing-Jing, XU Duan-Jun, CHEN Yao-Zu
    2002, 23(7):  1321-1323. 
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    The title compound was obtained as a by product in a contraction reaction by using DICas a coupling reagent. X-ray diffraction shows the title compound is a pyrrolinenitroxide radical urea. Two crystallographically independent molecules possess different conformations but the identical bond distances and angles. Based on the molecular structure a possible reaction mechanism is proposed for the reaction of DICand carboxylic acid.
    Enantioselective Total Synthesis of 12-Carboxyeudesma-3,11(13)-diene
    ZHOU Gang, CHEN Yong-Gang, GUAN Yu-Kun, ZHENG Guo-Jun, LI Yu-Lin 
    2002, 23(7):  1324-1326. 
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    The enantioselective total synthesis of 12-carboxyeudesma-3, 11(13)-diene(1) was achieved starting from(-)-dihydrocarvone in ten steps for the first time. The key steps mainly include the introduction of hydroxyl group into C-12 position of eudesmane by Vilsmeier chlorination and the generation of C3-C4 double bond into the eudesmane skeleton by elimination of halide.
    Diffusion of Oligomeric Penetrants in Rubbery Polymer Matrixes A Study of Simulation of Molecular Dynamics
    YU Kun-Qian, LI Ze-Sheng , LI Zhi-Ru, SUN Jia-Zhong
    2002, 23(7):  1327-1330. 
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    Molecular dynamics(MD) calculations are performed to simulate the diffusion of oligomers(from monomer to decamer) of methyl methacrylate(MMA) in polyMMAmatrix with a high molecular weight. The calculated diffusion coefficient constants are in the same trend as the experimental data with the degree of polymerization increasing. It is found that the diffusion coefficients of oligomers decrease rapidly from monomer to trimer and then keep nearly to be constant from tetramer to decamer as the degree of polymerization increases.
    Molecular Recognition and "on-off" Switching of Cyclo-bis(paraquat-p-phenylene) to Neutral Guests
    TENG Qi-Wen , WU Shi, CHEN Su-Qing, ZHANG Yan-Dong, ZHENG Xiao-Ming
    2002, 23(7):  1331-1334. 
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    AM1 and MNDOwere used to optimize supermolecular structures of cyclobis(paraquat-p-phenylene) to neutral guests and obtain ΔΔ Efor interchanging of complexes. Electronic spectra of four complexes were calculated with INDO/SCIbased on AM1 geometries, and it was indicated that their characteristic absorption peaks are red shifted compared with those of the host or the guests. Meanwhile the potential curve in the presence of H+ for the complex of the host and the biphenyl ether derivative was computed with AM1 and the mechanism of the "on-off" switching was discussed.
    Theoretical Studies on the Properties of Polyacene Doped with C60 as the Anode of Lithium Ion Battery
    ZHAO Yan-Ling, ZHOU De-Feng, PAN Xiu-Mei, SU Zhong-Min, WANG Rong-Shun 
    2002, 23(7):  1335-1338. 
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    According to semi-empirical method of AM1, the compounds which are located inside or outside C60 have been optimized. The results showed polyacenic semiconductor doped with C60 could absorb much more lithium ion, and lithium ions are easy to inset C60. The reason of improvement of polyacenic semiconductor conducting properties was analyzed theoretically, and the best doping proportion of C60 to polyacenic semiconductor was predicted.
    The Collisional Quenching of CCl2(A1B1) in Different Vibrational States by Alcohols and Ketones
    GAO Yi-De, CHEN Yang, Yang-Xue-Liang, CHEN Cong-Xiang
    2002, 23(7):  1339-1342. 
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    CCl2 free radicals were produced by dc discharge of CCl4(in Ar). Ground electronic state CCl2 radical was electronically excited to A1B1(0, 3, 0), (0, 4, 0), (1, 3, 0), (0, 6, 0), (1, 4, 0) and (2, 2, 0) vibronic states by Nd∶YAGlaser pumped dye laser at 550.56, 541.52, 532.25, 524.31, 523.82 and 523.37 nm respectively. The experimental quenching data of CCl2( A1B1and a3B1) by alcohols and ketones were obtained by observing time resolved fluorescence from the excited CCl2 radicals transition, which showed a superposition of two exponential decay components. The state-resolved rate constants kA and ka were acquired by analyzing and dealing with these data by using three-level model, which was put forward by us. It is found that the quenching rate constant is not dependent on the vibrational state.
    Surface Effect of ZrO2 Nanopowder in O2/H2
    WANG Xin-Ping, ZHAO Qin, LIN Qing-Song, CAI Tian-Xi
    2002, 23(7):  1343-1346. 
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    Akind of ZrO2 nanopowder annealed at different temperatures in H2 has been studied by ESR. On the surface of ZrO2, about 1×10-7 mol/g of Zr3+ centers are detected, which are the oxygen coordinatively unsaturated Zr. When the annealing temperature is lower than 400℃, the amount of Zr3+ center remains almost unchanged, while the amount of F-center increases in this temperature range, which may be resulted from the reduction of surface hydroxyl by H2. When the annealing temperature is higher than 400℃, O2- is originated on the surface of ZrO2, which may be formed from the reaction of Zr3+ and F-center with the trace amount of O2 in ordinary H2, and simultaneously, some Zr3+ centers are created, as being accompanied with the removal of surface hydroxyl.
    Synthesis, Characterization and Properties of Magnetic Nanometer-sized Solid Superacid
    ZHANG Mi-Lin, WANG Jun, MEI Chang-Song, JING Xiao-Yan, DUAN Xue
    2002, 23(7):  1347-1351. 
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    In this paper, magnetic solid acid catalyst of SO42-/Co0.5Fe2.5O4-ZrO2 with different molar ratios has been synthesized, and the influence of magnetic substrates Co0.5Fe2.5O4 on particle size, crystallizing temperature, and crystal structure of ZrO2 was investigated. The catalytic activity of the magnetic solid acid was studied for esterification reaction, and life, recovery and variation of magnetic property of the catalyst were tested. The results show that the addition of the magnetic substrate not only magnetizes but also delay the conversion from ZrO2(t) to ZrO2(m) during the formation of solid superacid, which makes acid sites on the surface of sample more stable and promotes its superacidity and catalytic activity. The conversion of esterification catalyzed by SO42-/Co0.5Fe2.5O4-ZrO2 can reach 97.31% and 74.69% conversion can be obtained after it was used for 6 times in the reaction and after it was regenerated, the conversion reaches 96.25%, meaning that the catalytic activity of this catalyst may be recovered.
    Effect of Spacer Chain Length on Aggregation of C12-s-C12·2Br Dimeric Surfactants in Aqueous Solutions
    ZHENG Ou, ZHAO Jian-Xi, YOU Yi
    2002, 23(7):  1352-1355. 
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    Effect of spacer chain length on aggregation of C12-s-C12·2Br dimeric surfactants in aqueous solutions has been investigated by using conductivity and viscosity measurements as well as steady fluorescence quench technique. The results showed the ability for the micelle formation of C12-s-C12·2Br dimeric surfactants is much better than that of their monomer, dodecyltrimethylammonium bromide(C12 TABr). The values of cmc for the former are lower than an order compared with the latter. The aggregation number Nof C12-s-C12·2Br micelles decreases with increasing concentration c, specially for s=2, the value of Nincreases rapidly at c>7.7 mmol/L. The calculated result indicates a significant change in the micellar shape and the formation of prolate ellipsoid micelles at c>7.7 mmol/L. The viscosity measurement for C12-2-C12·2Br micellar solutions demonstrates the calculated results.
    Theoretical Study of Armchair Single-walled Carbon Nanotubes
    LI Rui-Fang, SHANG Zhen-Feng, WANG Gui-Chang, PAN Yin-Ming, ZHAO Xue-Zhuang 
    2002, 23(7):  1356-1359. 
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    Armchair single-walled carbon nanotubes (3, 3) with different lengths were studied by AM1 and PM3 methods. We found that the hexagons in the ASWCNTs are distorted. The sum of the square of the orbital coefficients in one layer of the frontier orbitals decreases in zigzag manner from the middle to the edge of the nanotubes. The characteristic infrared absorptions of (3, 3) armchair single-walled carbon nanotubes caculated by AM1 method are between the wave number 1290 and 1645 cm-1.
    A Study of the Electronic Structure of Energetic Material Hexanitrohexaazaisowurtzitane by B3LYP Method
    ZHOU Ge, WANG Jing, HE Wen-Di, TIAN Shuang-He, TIAN An-Min, WEN Zhong, ZHAO Peng-Ji, XU Zhi-Lei
    2002, 23(7):  1360-1362. 
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    The geometry of hexanitrohexaazaisowurtzitane(CL-20) is optimized at the B3LYP/631G** level. The population, natural bond orbital and vibrational frequency analyses are carried out. Apossible stable molecular geometry is obtained, which is in agreement with the experimental results. The relationship between the bonding behavior and the properties of CL-20 has been discussed.
    Liquid-phase Hydrogenation of Furfural to Tetrahydrofurfuryl Alcohol Catalyzed by Polymer Resin Supported Palladium Catalysts
    YIN Jing-Bo, CHEN Xue-Si, ZHANG Long, LIU Ao, YANG Ya-Nan, YIN Min, LOU Ling
    2002, 23(7):  1363-1366. 
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    Three kinds of polymer resin supported Pd catalysts were prepared by mixing PdCl2 with alkaline styrene anion exchange resins[D392 -NH2, D382, -NHCH3, D301R, -NH(CH3)2], strongly alkaline styrene anion exchanged resin[201×7DVB, -NH+(CH3)3] and alkaline epoxy exchange resin (701, -NH2), and hydrogenating in liquid phase at 1.013×105Pa. The hydrogenation of furfural was studied under the reaction conditions such as solvent, temperature, Pd content in the supported catalyst and the amount of the catalyst. The yield of hydrogenation reaction of furfural markedly increased to 100% and the selectivity to tetrahydrofurfuryl alcohol increased to over 98% by polymer(alkaline styrene anion exchange resins D392, -NH2, D382, -NHCH3) supported palladium catalysts comparing with the yield over 70% and selectivity over 97% by palladium catalyst, in 50% alcohol 50% water or pure water solution at 1013×105Pa. The relationship between hydrogenation and the structures of functional group in the supporting resin was examined by XPSmethod.
    Electrocatalytic Performance of Pt-TiO2/C Complex Catalysts for Oxidation of Methanol
    LIU Chang-Peng, YANG Hui, XING Wei, LU Tian-Hong
    2002, 23(7):  1367-1370. 
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    It is reported for the first time that the Pt-TiO2/Ccatalyst prepared with chemical reduction and sol-gel method showed the excellent electrocatalytic activity and stability for the electrooxidation of methanol. When the atom ratio of Ti to Pt in the catalysts is 1/2, the catalysts showed the best electrocatalytic properties. After the catalyst is treated at 500 ℃, the performance is further improved. It is hopeful to use the catalyst in the pratical DMFC.
    Preparation of Titanium Dioxide Fibers and Their Photocatalysis Reactivity
    YANG Zhu-Hong, BAO Ning-Zhong, LIU Chang, FENG Xin, XIE Jing-Wei, JI Xiao-Yan, LU Xiao-Hua
    2002, 23(7):  1371-1374. 
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    Titanium dioxide fibers(TiO2) were prepared from K2Ti 4O9 fiber precursors by ion exchange reaction in hydrochloric acid. The photocatalytic reactivity of titanium dioxide fibers was studied with helianthin Bas a model compound of waste water and the property of suspension sedimentation at different pHvalues was studied. The results show that TiO2 fibers have good photocatalysis properties equivalent to the commercial micron size TiO2. Furthermore, the serious agglomeration appears at pH=6.0 and can be easily separated from solution.
    Diffusion Coefficient of Lithium for Intercalation in Highly Oriented Pyrolytic Graphite
    NU LI Yun-Na, WAN Chuan-Yun, YAN Man-Ming, ZHUANG Ji-Hua, JIANG Zhi-Yu 
    2002, 23(7):  1375-1378. 
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    The diffusion coefficient of lithium in Highly Oriented Pyrolytic Graphite(HOPG) was measured by using electrochemical impedance spectra(EIS) and potential step methods in 1mol/L LiPF6, V(EC)∶V(DMC)=1∶1 solution. It was found that the resistance of SEIfilm and the polarization resistance decreased with the increase of lithium intercalation degree. Aagreement was obtained between the diffusion coefficient values measured from these two methods. The diffusion coefficient of lithium in HOPGdecreased from 10-11 cm2/s to 10-12 cm2/s in the potential region of 0.2-0.05 V.
    Experimentation on Induction of Tumor Cell Apoptosis by Temperature and Anti-tumor Medicine
    LI Li, ZHANG Jia-Min, HU Yuan-Yang, FENG Ying, QU Song-Sheng
    2002, 23(7):  1379-1382. 
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    Techniques from microcalorimetry and transmission electron microscopy(TEM) were employed to investigate the metabolic effects and the ultrastructural changes of human body carcinoma of ovary cell line(COC1) at different temperatures with and without synergetic effects of anti tumor medicine(HCFU). The mechanism of hyperthemia and chemotherapy in the treatment of the tumor cells was explored at both macroscopic and microscopic levels. The results showed that the metabolic activity of the tumor cells was reduced at high temperature and the cell morphology changed malignantly. High temperature might induce apoptosis of the tumor cells; and the combined effects of hyperthemia and chemotherapy could speed up the apoptosis and reduce the metabolic power of the tumor cells. Asustained longer time action could lead to ultimate death of the tumor cells.
    Preparation of Polymer Electrolyte for Lithium-ion Battery
    REN Xu-Mei, GU Hui, CHEN Li-Quan, WU Feng, HUANG Xue-Jie
    2002, 23(7):  1383-1385. 
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    With the final goal of developing lithium ion batteries having a plastic configuration, we have characterized a high conducting microporous PVDFplastic electrolyte for lithium ion batteries prepared by using the phase inversion process. Gel polymer electrolyte composed of PVDF-based microporous membrane, LiPF6-EC/DECshow a high ionic conductivity (above 10-3S/cm at room temperature), and good mechanical properties(102 kg/cm2). The half cells consisting of Li/GPE/MCMBshow excellent cycling characteristics and the stable discharge capacity is 306 mA·h/g. At a current density of 1.0 mA·h/cm2(0.5 C), the cell was shown to retain 79% of initial capacity after 100 cycles.
    Direct Fabrication of Protein Arrays Using Dip-Pen Nanolithography
    WEI Li, HONG Xia, GUO Wei, BAI Yu-Bai, LI Tie-Jin
    2002, 23(7):  1386-1388. 
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    This paper covers the first application of Dip-Pen Nanolithography(DPN) to directly write protein patterns with submicrometer dimensions onto Au substrate. Using Bovine Serum Albumin(BSA) as the ink in the DPNprocedure, we were able to utilize lateral force microscopy(LFM) images to differentiate between Au substrate and patterned area with deposited monolayers of BSA. Then the first evidence for Au_ Sbonding was reported between the gold substrate and the BSAsurface thiol groups given by the angle resolved XPSmeasurements.
    Highly Effective Extraction and Electrochemical Properties of Sm-metallofullerene
    SUN Bao-Yun, LI Mei-Xian, GU Zhen-Nan 
    2002, 23(7):  1389-1391. 
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    Sm@C82 (Ⅲ) was effectively extracted by the high-temperature-DMF extraction and separated in one step HPLC, making the further studies of its properties possible. The successful purification of Sm metallofullerene with such a low yield indicates that the high-temperature-DMF extraction is much effective. The cyclic and differential pulse voltammgrams of the pure Sm@C82 (Ⅲ) were first measured, indicating that it has a good electron accepted ability. Up to 6 electrons can be added to them. The analysis of the potentials, the potential differential and the number of electron transferred show that Sm prefers to take +2 charge state in the carbon cage. The study of electronic structure would help us to produce, extract more metallofullerenes and synthesize useful materials.
    Immobilization of Plant Protoplast on Gold Electrode Surface
    ZHANG Hong-Ping, QI Yu-Lan, YAN Man-Ming, WEI Yi, LIN Zhong-Hua, JIANG Zhi-Yu
    2002, 23(7):  1392-1394. 
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    Barley protoplast was immobilized on poly(dially-dimethylammonium) (PDADMAC) modified gold electrode via the electrostatic attraction between the positively charged amine groups of PDADMACand the negatively charged barley protoplast. STMimage reveals that PDADMAC/Au(111) surface displays a nano-organized dot(4-6 nm) array structure. The processes of the PDADMACadsorption and of the barley protoplast immobilization were monitored from the in situ QCMfrequency change. The effects of the adsorbed mass and of the density and viscosity of medium on the frequency change of QCMwere discussed, respectively. The QCM result shows that the thickness of the adsorbed PDADMAClayer is 2.4 nm.
    Studies on Characterization of Active Sites of Sulfided PtMo/γ-Al2O3 Catalysts by Using Low Temperature FTIR Spectroscopy of Adsorbed CO and Their Thiophene HDS Activity
    QI Xing-Yi, GUO Lin, LI Wen-Zhao, XIN Qin, Michel-Lacroix, Michel-Vrinat, Francoise-Mauge
    2002, 23(7):  1395-1397. 
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    Aseries of sulfided PtMo/γ-Al2O3 catalysts[ w (Mo)=9.0%] with different contents of Pt were characterized by using low temperature FTIRspectroscopy of adsorbed CO, while their HDS activity was investigated with thiophene as a model substrate. Experimentally, it was found that no existence of the bands related to the surface complexes of Al 3+ ←COand Pt0←CO→Pt0 was observed at 77 Kand that the rate of the thiophene HDS reaction(573 K) is well linearly proportional to the area of the Pt0←COband at 2093 cm-1 with a higher extrapolated HDS rate compared to that of sulfided Mo/γ-Al2O3 catalyst at the zero content of platinum. On the basis of the results here, the conclusion may be made that the active monolayer phase of Pt Mo Smay be formed over sulfided PtMo/γ-Al2O3 catalysts during the sulfidation process and that both Mo 2+ and Pt0 sites for COadsorption should be the active reaction centers of thiophene HDS .
    Structure and Photocatalytic Performance of SO42-/TiO2-SiO2 Solid Superacid
    SU Wen-Yue, CHEN Yi-Lin, FU Xian-Zhi, WEI Ke-Mei
    2002, 23(7):  1398-1400. 
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    Aseries of SO42-/TiO2-SiO2 catalysts with different mass fractions of SiO2 were prepared by sol gel method. The effect of adding SiO2 on the crystal structure, specific surface area, oxygen adsorption, and acidity of SO42-/TiO2 catalyst and its photocatalytic property for degradation of bromomethane was studied. The results showed that the specific surface area and amount of oxygen adsorption of catalyst were increased by addition of SiO2, leading to the obvious increase on photocatalytic activity of SO42-/TiO2-SiO2 catalysts and mineralization ratio of bromomethane. Comparing with SO42-/TiO2, the acidic strength and anti moisture ability of SO42-/TiO2-SiO2 catalyst were decreased.
    Synthesis and Characterization of Nano-Hg2Cl2/Al2O3 Ordered Array System
    WANG Yin-Hai, MO Ji-Mei, CAI Wei-Li, YAO Lian-Zeng, LIU Yan-Mei
    2002, 23(7):  1401-1403. 
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    We have prepared ordered porous alumina membrane. Metal Zn was deposited within the pores of alumina membrane by direct current. The alumina membrane with Zn in the pores was immersed in HgCl2 solution and Hg2Cl2/Al2O3 ordered array was synthesized by utilizing Zn reduced HgCl2. The XRDand TEMmeasuring demonstrated Hg2Cl2 located in the pores of alumina membrane and the diameters range from 30 to 80 nm.
    Effects of Ring-substituted Groups on the Properties of Metallized Polyaniline Membrane Modified Electrode
    DAI Li-Zong, XU Yi-Ting, Jean-Yves-GAL, WU Hui-Huang
    2002, 23(7):  1404-1408. 
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    By comparing the redox potentials of poly-2, 5-dimethoxyaniline(PDMAn), poly-o-toluidine(POT ) and poly m chloroaniline(PmClAn) membrane modified electrodes, the morphology and crystal face orientation of Pt deposited on these polymers and isopropanol oxidation behavior on the platinized polyaniline electrodes, the relation of electrochemical properties of polyanilines to ring substituted groups in the polymers and the influence of different polyaniline on Pt deposition and the catalytic properties of platinized polyaniline modified electrodes were discussed in terms of the electronic and steric effects. The results indicated that among 3polyanilines, the redx potential of PDMAn was the most negative, and that of POT was less negative, and that of PmClAn was the most positive. The electrodeposition mechanisms of Pt particles on POT and on PDMAn membranes were different from that on PmClAn membrane. The Pt particles deposited on polyanilines were inclined towards the preferred orientation of Pt(200) crystal face, but the degree of preferred orientation depended on polymers. The preferred orientation on POT was stronger than that on PDMAn, and the weakest on PmClAn. The potentials of isopropanol oxidation on platinized polyaniline modified electrodes rely on the nature of polyanilines matrix. On POT modified electrode the isopropanol oxidation mainly occurs in the potential region where POT is electroactive, but on PDMAn and PmClAn modified electrodes it takes place in the potential region same as that on Pt. It follows that polymer matrix was not only as disperse media of Pt particles, but also exerts catalytic actions.
    Synthesis and Properties of the Copolymers Containing Both Conjugated Block(PPV) and Nonconjugated Block(PS) Segments
    ZHANG Ming, TANG Jie-Cong, LI Guo-Wen, ZHANG Rui-Feng, SHEN Jia-Cong
    2002, 23(7):  1409-1412. 
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    Three kinks of poly( p-phenylenevinylene)(PPV) copolymers with a conjugated block and nonconjugated polystyrene(PS) were synthesized by p-quinomethane active intermediate. The chemical structure of the copolymers was determined and confirmed by 1H NMRand FTIR. The introduction of flexible segment PSin the PPVtype of polymer leads to the interruption of conjugation, which shortens the effective conjugated length and improves their solubility and processibility for LEDdevices. In comparison with PPV, the copolymers containing both conjugated and noncojugated segments result in light emission of blue shifting, enhancement of luminescence efficiency and tuning color of emission light. The experiment results indicate that the polymerization of conjugated segment and noncojugated segment by p-quinomethane intermediates is a new and effective synthetic route for the copolymers.
    Studies on the Formation of Physical Hydrogels During a Monomer Post-added Microemulsion Polymerization of PMMA
    矹IANG Wan, WANG Lei, LI Ming-He, WANG Chang-Chun, FU Shou-Kuan
    2002, 23(7):  1413-1416. 
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    Nearly transparent PMMAphysical hydrogels were formed during a monomer post-added microemulsion polymerization procedure by using ammonium persulfate(APS) as an initiator at a higher temperature up to 70 ℃. SEMobservations suggested that a lot of nanoparticles would be able to connect one another to form a physical network.The factors which affect the formation of these hydrogels were discussed and the formation mechanism was proposed in this paper.
    Studies on the Membrane Strength of Alginate/Chitosan Microcapsule Prepared by Emulsification/Internal Gelation Method
    LIU Qun, XUE Wei-Ming, YU Wei-Ting, LIU Xiu-Dong, YAN Ruo-Yuan, LI Jin-Yun, MA Xiao-Jun
    2002, 23(7):  1417-1420. 
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    The alginate/chitosan microcapsule was prepared by emulsification/internal gelation method. It was found that the membrane strength was significantly affected by the molecular weight of chitosan, reaction time of these two polymers and the pHvalue of chitosan solution. When the molecular weight of chitosan was lower than 0.1 million, reaction time was higher than 15 min, pHof chitosan solution was about 6.0, then the most strongest membrane was obtained. At the same time the principle of the reaction of polyelectrolyte complexation was investigated.
    Preparation of a New Adsorbent for Binding Low Density Lipoprotein
    XU Jian-Kuan, HE Bing-Lin
    2002, 23(7):  1421-1424. 
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    Anew adsorbent for binding low-density lipoprotein was prepared by the immobilization of sulfuric group on crosslinked poly(vinyl alcohol) bead. Spacers with different lengths were introduced, by the reaction with polyethylene polyamine, to the crosslinked poly(vinyl alcohol) bead with epoxy group, and then sulfuric group was immobilized by the reaction with DMF/ClSO3H. It was found that this method could increase the amount of immobilized sulfuric group, which increased with decreasing crosslinking degree and increasing PVAconcentration. The adsorption experiments in vitro showed that this kind of adsorbent had a satisfactory adsorption capacity and selectivity.
    Structures and Properties of PA6/PP/SBS Blends Prepared by Pan-milling
    AO Ning-Jian, WANG Qi
    2002, 23(7):  1425-1428. 
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    Anovel technique to modify the morphology and thus to enhance the mechanical properties of polyamide 6(PA6)/polypropene(PP)/styrene-butadiene-styrene triblock copolymer(SBS) blends was reported. Ultra fine PA6 and PPparticles were prepared by using the pan type milling equipment and were mixed with SBSto produce blends. The phase structure of the blends was studied with TEMand the mechanical properties of the blends processed at different temperatures were also investigated. The PA6 PPco powder prepared by pan milling shows the improved compatibility and interfacial action with SBS. When the addition of PA6/PPwas 4%~8%, the tensile strength of the blends was enhanced greatly and the elongation at break changed little. With the variation of the processing temperature, phase structure of PA6/PPchanged remarkably and the PPparticles adhered to form chain structure and the performances of the blends were further promoted.
    Affinity Adsorbents for N-Demethylvancomycin
    ZHAO Qing-Xiang, YAN Hu-Sheng, CHENG Xiao-Hui, HE Bing-Lin
    2002, 23(7):  1429-1432. 
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    Poly( N-hydroxyethyl acrylamide) resin was prepared by reacting ethanolamine with crosslinked poly(methyl acrylate). α Hydroxyl chloroethyl groups were introduced into the resin by treating the resin with epichlorohydrin with the acid catalysis. Three adsorbents with D-alanine, Lananine or glycine, respectively, were made by reacting the α hydroxyl chloroethyl group containing resin with the corresponding amino acids. The results of adsorbing N-demethylvan-comycin of the adsorbents indicated that the adsorbent with D-alanine had the highest adsorption capacity, the second was the adsorbent with glycine, while the adsorbent with Lalanine didn't adsorb N-demethylvan-comycin. The optimal pHfor the adsorption for adsorbent with D-alanine was ~5.8 and the adsorption capacity decreased with increasing salt(NaCl) concenttration. The adsorbed N-demethylvan-comycin was completely desorbed with 0.4 mmol/L Na 2CO3/CH3CN(molar ratio 7∶3, pH=9.5).
    One-step Synthesis of High Tg Organo-soluble Side-chain Fluorinated Polyimides Containing a Triazine-azo Chromophore
    PAN Xiao-Xia, SUI Yu, XU Hong-Jie, YIN Jie, LIU Yan-Gang, GAO Jian, ZHU Zi-Kang, HUANG De-Yin, WANG Zong-Guang
    2002, 23(7):  1433-1436. 
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    Aseries of fluorinated copolyimides containing a triazine azo chromophore were prepared by a one step method. The copolyimides obtained were characterized by FTIRspectra, UV-Vis spectra, DSC, TGAand the prism coupling device. The copolyimides are soluble not only in aprotic organic solvents such as Nmethyl 2 pyrrolidone(NMP), N, Ndimethyl acetamide(DMAc), N, Ndimethyl formamide(DMF), dimethylsulfoxide(DMSO), but also in low boiling point solvents such as ethyleneglycol monomethyl ether and tetrahydrofuran(THF). They are almost completely transparent at wavelengths greater than 500nm. All copolyimides possess high glass transition temperatures(Tg, 544-562 K) and are almost independent of the chromophore loading level. The 5% weight loss temperatures( T5) of the copolyimides are more than 100 Khigher than the corresponding Tgs and this high thermal stability would ensure high temperature electric poling of the copolyimides. The in plane refractive index of a copolyimide is increased as the chromophore content is increased.
    Rheological Characterization of Lightly Sulfonated Polystyrene Ionomers and Its Blends with Precursor Polystyrene
    WANG Jin, ZHENG Xue-Jing, LIU Chen-Yang, CHENG Xing-Guo, HE Jia-Song 
    2002, 23(7):  1437-1443. 
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    The rheological properties of 0.98%(molar frac‘tion) lightly sulfonated polystyrene ionomer(SPS), zinc neutralized SPS(ZnSPS) and their blends with precursor polystyrene(PS) are reported. It is found that the rheological properties of ionomers and their blends are quite different with PS, due to the ionic aggregates acting as physical cross links in ionomers. Using linear viscoelasticity data, the time-temperature superposition can be conducted to all samples. Differences are also found in the low frequency region of linear viscoelasticity data. Correlated with the relaxation of polymer chains, the moduli of ionomers are higher than those of PSdue to the effect of ionic aggregates. In the steady shear test, typical yield phenomena can be found in the apparent viscosity curves of ionomers, which are also resulted from the ionic aggregates. Utracki's formula for yield stress fits the apparent viscosity data properly and the yield stress and zero shear viscosity of ionomers are obtained. It is also found that the yield phenomena of ionomers are disappeared above certain temperature. The Cox-Merz rule is invalid for ionomers, due to the complex viscosity and apparent viscosity characterizes at different state of ionomer fluid, with ionic aggregates and breakdown of ionic aggregates, respectively. Finally, the different relationship between blends composition and rheological properties indicate that different ionic aggregate structure or ionic association exists in the PS/SPSand PS/ZnSPSblends.
    Electrochemical Properties of Electric Double-layer Capacitors Using Activated Carbon as Their Electrodes Prepared from Pyrolytic Treatment of Phenol Formaldehyde Resin
    HUANG Xiao-Wen, XIE Zhong-Wei, QU Xiao-Guang, SUN Hai-Zhu, QU Lun-Yu, XIE De-Min
    2002, 23(7):  1444-1446. 
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    Electric double-layer capacitors using activated carbon as their electrodes are peculiar power sources with a high reliability, it is extremely resistant to oxidation, chemical and heat treatment. In this paper, we have developed the material of electric double-layer capacitors prepared from pyrolytic treatment of phenol formaldehyde resin. The experiment results of its electrochemical properties show that this kind of capacitor has a large capacity, good cycle life and can be used in a large scale.
    Cooperative Motion Algorithm from Dynamic Monte Carlo Simulation of Polymer
    QIN Yuan, LIU Hong-Lai, HU Ying
    2002, 23(7):  1447-1449. 
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    A Monte Carlo simulation algorithm of polymer was proposed, which was similar to the cooperative motion algorithm in literatures. In this algorithm several segments of the polymer can move cooperatively, this may be interpreted as the effect of tensile force in the polymer chain. Its dynamic behavior is in agreement with the Rouse theory, so it can be used as a dynamic Monte Carlo simulation algorithm.
    Self-assembly and AFM Study of Ultra-thin Films of Cellulose Sulfate Salt and Chitosan
    LI Wan, YAN Li-Feng, LIN Wei, ZHU Qing-Shi
    2002, 23(7):  1450-1452. 
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    Tosyl cellulose sulfate sodium and chitosan ultra thin films were self assembled through electrostatic attraction on the positively charged quartz substrate. The morphologies obtained by AFMdemonstrated that the arrangement of the polymer chains transformed from original irregularity into well-alignment and the thickness of the films was around 1-2 nm. The films were stable enough for constructing functional ultrathin films.