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    24 October 2003, Volume 24 Issue 10
    Articles
    Effect of Val162 Mutation on Structure and Function of Cytochrome c Oxidase Soluble Domain
    SONG Ai-Xin, LI Lian-Zhi, HUANG Zhong-Xian
    2003, 24(10):  1733-1737. 
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    The effect of Val162 mutation(potentially relative to cancer) on cytochrome coxidase soluble Cu Adomain was studied by site-directed mutagenesis technique combined with UV-Vis, CD, fluorescence spectra, EPR and rapid kinetic methods.It is found that the mutation at the Val162site leads to a structural transformation and decreasing electron transfer activity.It provides important information for understanding the pathological mechanism.
    Fabrication and Characterization of La0.8Ca0.2MnO3Nanowires
    ZHANG Hui, MA Xiang-Yang, XU Jin, YANG De-Ren
    2003, 24(10):  1738-1741. 
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    La0.8Ca0.2MnO3nanowires were prepared by using a simple sol-gel method with nano-channel alumina(NCA) as template.The effects of two kinds of annealing methods on the structure, morphology of La0.8Ca0.2MnO3nanowires were investigated.The diameter of La0.8Ca0.2MnO3nanowires prepared by ramping the furnace temperature directly to 800℃ with a rate of 10℃/min is larger than that of pores within NCA.While, the diameter of La0.8Ca0.2MnO3nanowires prepared by ramping the furnace temperature to 400 ℃ with a rate of 2 ℃/min and keeping at this temperature for 1h, then ramping to 800 ℃ with a rate of 10 ℃/min and keeping at this temperature for 2h is nearly equivalent to that of pores within NCA.XRDand selected area electron diffraction indicate that the nanowires derived under the two annealing conditions are of monoclinic perovskite structure.It is demonstrated that the La0.8Ca0.2MnO3nanowires with monoclinic perovskite structure can be fabricated at low temperatures by employing a solution route.The method presented in this paper is also feasible for fabricating the nanowires of other mono-component and multi-component oxides.
    Uptake of 99mTcN-MIBI in Tumor Cells in vitro and the Comparison of it with 99mTc-MIBI
    ZHANG Xian-Zhong, TIAN Yan-Cong, WANG Xue-Bin, LUO Qian
    2003, 24(10):  1742-1746. 
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    In this study, the uptake of 99mTcN-MIBIand99mTc-MIBIwere investigated by colorectal cancer cell line CL-187, lung cancer cell line L-973 and breast cancer cell line MCF-7 in vitro, respectively.The results of uptake kinetics shows that 99mTcN-MIBI has maximal accumulations between 20 and 40 min after incubation in all of these tumor cells, and the accumulation(D%) of 99mTcN-MIBIwas found to be significantly higher than that of 99mTc-MIBI, especially in colorectal cancer cell line CL-187. Up take of 99mTcN-MIBIdecreased in the order MCF-7→CL-187→L-973. The maximal accumulation occurring at 40 min after incubation of99mTcN-MIBI in MCF-7 with the uptake rate about 30% per 105cells.The influences of the culture conditions, such as cell concentration and incubation temperature, on the accumulation were also investigated, and the uptake of 99mTc-complexes by cells were affected significantly by the culture conditions.
    Synthesis and Characterization of Water-soluble Metallofullerene Derivatives
    SUN Bao-Yun, GU Zhen-Nan
    2003, 24(10):  1747-1749. 
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    Three water-soluble metallofullerene derivatives have been synthesized.IRand XPSanalysis indicate that they have average compositions of Gd@C82(OH)22, Gd@C82(OH)6(NHCH2CH2SO3H)8and Gd@C82(OH)5(NHCH2COOH)9, respectively.They are particularly interesting in medical application.
    Growth of <110> Oriented ZnO Films Used for SAWF by MOCVD
    ZHAO Bai-Jun, DU Guo-Tong, WANG Jin-Zhong, YANG Hong-Jun, ZHANG Yuan-Tao, YANG Xiao-Tian, MA Yan, LIU Bo-Yang, YANG Tian-Peng, LIU Da-Li
    2003, 24(10):  1750-1752. 
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    ZnO films with <110> orientation were grown on R-Al2O3substrates by LP-MOCVD, and the growth temperature was optimized.The quality of crystal, surface morphology and optical characteristic of the samples were investigated by XRD, AFM and PLmethod.The experimental results show that the FWHM of the optimized sample is only 0.50°. Compared with that of the sample grown on C-Al2O3materiaLUnder the same conditions, the surface morphology of the first sample is denser and smooth, while the PLspectra indicate that the exciton emitting intensity of <110> oriented ZnO film in the ultraviolet range is lower.However, the deep-level emission related to the intrinsic defects disappears in the spectrum.All above indicate that the <110> oriented ZnO film is more suitable for fabrication of the film SAWF with a low loss and a high frequency than for fabrication of the emitting device in ultraviolet range.
    Design of New Polypyridyl Ligands and Their Effects on DNA-binding Mechanisms of Complexes
    ZHANG Qian-Ling, LIU Jian-Hong, LIU Jian-Zhong, REN Xiang-Zhong, ZHANG Pei-Xin, WEI Bo, XU Hong, JI Liang-Nian
    2003, 24(10):  1753-1755. 
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    Two structurally related polypyridyl ligands ODHIP(3,4-dihydroxyl-imidazophenanthroline), MDHIP(2,4-dihydroxyl-imidazo phenanthroline) and their ruthenium(II) complexes [Ru(phen)2ODHIP]2+and [Ru(phen)2MDHIP]2+were prepared and characterized.Their DNA-binding properties were studied by spectroscopic methods and viscosity measurements.The results indicated that the two complexes are bound to DNA by different modes due to the different planarities of ligands.For the complex [Ru(phen)2MDHIP] 2+, the 2-position ortho group of MDHIP could form an intramolecular hydrogen bond with the nitrogen atom of the imidazole ring to extend the planarity and strengthen the binding affinity.On the other hand, the 4-position ortho group hindered the complex from intercalating into the base pairs of DNA, and finally, making the complex bind to DNA by a partial intercalative mode.However, for the complex [Ru(phen)2ODHIP]2+, there was no intramolecular hydrogen bond formed and the two ortho groups further increased the steric effect and decreased the binding affinity, thus making the complex bind to DNAby groove binding mode.
    Synthesis of Calcium Fluoride Nanoparticles from Microemulsion
    HUA Rui-Nian, LEI Bing-Fu, XIE De-Min, SHI Chun-Shan
    2003, 24(10):  1756-1764. 
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    Calcium fluoride nanoparticles were synthesized by water/cetyltrimethylammonium bromide (CTAB)/2-octanol microemulsion systems.X-ray powder diffraction analysis showed that the products were a single phase.The result of scanning electron microscopy confirmed that the average sizes of the calcium fluoride particles were below 100 nm in diameter.With decreasing water content and reaction time, the particle sizes decreased.
    A Study on Assembly of a Rare Earth Complex [C5H5NC16H33] [Eu(TTA)4] in the Channel of Si-MCM-41
    XU Qing-Hong, LI Hong-Wu, LI Lian-Sheng, ZOU Yong-Cun, XU Ru-Ren
    2003, 24(10):  1758-1769. 
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    It was proved by ICP, fluorescence spectra and N2adsorption that the rare earth complex [C5H5NC16H33] [Eu(TTA)4] is in the channel of Si-MCM-41 in the course of assembly.The rare earth complex of 67.9% is in the channel, suggesting that the assembly of the complex molecular on the mesoporous MCM-41 was carried out mainly in the channel.
    Real-time Visualization of Ligation Reaction Catalyzed by E.coli DNA Ligase Based on Molecular Beacon
    LIU Ling-Feng, TANG Zhi-Wen, WANG Ke-Min, TAN Wei-Hong, LI Jun, GUO Qiu-Ping, MENG Xiang-Xian, HUANG Shan-Sheng, LI Du
    2003, 24(10):  1761-1774. 
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    Nucleic acids ligation is a crucial step in replication and repair of DNA and in genetic recombination.Researches on DNA ligation have been generally based on gel electrophoresis and autoradiography in the past, which include complex work and are time-consuming.In this paper, a novel approach was developed for real-time monitoring of DNA ligation process.By using this approach, DNA ligation process can be monitored in real-time providing abundant, successive, dynamic and real-time data, which is of great importance for the mechanistic studies and dynamics research of DNA ligation.Ulteriorly, a qualification assay method for the ligase is developed, with a linear range from 4.0×10-6to 2.0×10-4U/μLand a detection limit of 4.0×10-6U/μL.
    Preperation of Poly(ferulic Acid) Glassy Carbon Modified Electrode and Its Electrocatalytic Oxidation of NADH
    ZHANG Yu-Zhong, ZHAO Hong, YUAN Zhuo-Bin
    2003, 24(10):  1765-1768. 
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    The preparation of poly(ferulic acid) glassy carbon modified electrode and its electrochemical properties were studied.The modified electrode gives a quasi-reversible redox peaks in 0.1 mol/Lphosphate buffer solution(pH=6.60) over the potential range from -0.1 to 0.5 V(vs.Ag/AgCl), in which the formal potential is 0.188V(vs.Ag/AgCl).The formal potential shifts in a negative direction with the increasing of pHvalues.The electrode reaction contains one electron and one proton.The PFA modified electrode shows an electrocatalytic activity for the oxidation of NADH in 0.1 mol/Lphos phate buffer solution.The apparent electron transfer rate constant(ks) and transfer coefficient for electron transfer between the electrode surface and immobilized PFA were calculated as 6.6 s-1and 0.496, respectively, the diffusion coefficient of NADH was calculated as 1.76×10-6cm2/s by using chronoamperometric results.The peak currents were proportional to the concentrations of NADH in the range of 0.01-5.0 mmol/L.Finally the heterogeneous rate constant for the oxidation of NADHon the PFAmodified electrode surface was also determined and found to be about 6.82×103 mol-1·L·s-1.
    Kinetic Characteristics of the Interaction Between Morphine and Its Antibody by SPR Competitive Immunoassay
    CHEN Shou-Hui, CUI Xiao-Qiang, YANG Fan, NI Yong-Nian, YANG Xiu-Rong
    2003, 24(10):  1770-1774. 
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    It is impossible for surface plasmon resonance to measure directly the binding kinetics between a low-molecular-weight analyte interacting and its immobilized binding partner.Solution competition method was applied to the kinetic study of the interaction between morphine and its antibody.The affinity constant between the antibody of morphine and morphine-BSAimmobilized on the sensor chip was also obtained.The result showed that the affinity of polyclonal antibody is stronger than that of monoclonal antibody.And it also indicated that the protein combined with the analyte affected the binding of antibody to antigen.
    Enhancement of Signal-to-Noise Ratio in Chip-based Capillary Electrophoresis Systems by a Hadamard Transform Approach
    ZHANG Tao, FANG Qun, FANG Zhao-Lun
    2003, 24(10):  1775-1778. 
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    The first demonstration of Hadamard transform capillary electrophoresis(CE) is reported for enhancing the signal-to-noise ratios(S/N) on a microfluidic chip using a simple electrokinetically gated injection approach in this paper.Sample or running buffer was alternatively injected into the separation channel according to a 7-bit, 127-step pseudorandom binary sequence(PRBS).The electrophoregram rebuilt from detector signal with inverse Hadamard transform improved the S/Nratio by a factor of 5(5.6 in theory), compared to conventional single injection electrophoregram, almost without affecting the sample throughput.
    Studies on Quantized Capacitance Charging of Monolayer-protected Clusters with Microelectrode
    CHEN Yu-Jing, HU Xiao-Ya, WANG Cheng-Yin, GOU Rong
    2003, 24(10):  1779-1783. 
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    Measuring the quantized capacitance charge of the C6Au monolayer protected clusters(MPCs) in the dichloromethane solution with the microelectrode was reported.The results from cyclic voltammetry(CV) and differential pulse voltammetry(DPV) showed five pairs of quantized capacitance charging peaks in dichloromethane solution.The average capacitance of single MPCs was obtained from the result of DPV.Single potential step chronocoulometry was used to demonstrate that each pair of the peaks corresponded to one electron transferring across the interface of the MPCs.From the i l,s of the CV of the microelectrode, the charge transfer coefficient α was evaluated.Compared to the conventional Pt electrode, the microelectrode exhibits obvious and well-defined peaks, and is favorable in the study of MPCs in the solution with a high impedance without supporting electrolyte and in the process of high sweep rate.
    HPLC and ESI-TOF-MS Analysis of the Anomeric Isomers of Morroniside
    YAN Cun-Yu, ZHAO Yi-Min, QIAO Shan-Yi, LIU Qin, XIE Jian-Wei, ZHANG Yong-Xiang
    2003, 24(10):  1784-1786. 
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    Morroniside consists of two anomeric isomers, α-morroniside and β-morroniside.These two anomeric compounds have been separated by reversed-phase high-performance liquid chromatography(HPLC) using a gradient mobile phase of acetonitrile-water at 7 ℃, and verified to be anomers of morroniside by ESI-TOF-MS.The higher peak in the chromatogram was appointed to α-morroniside according to NMR data reported in previous literature.The molar ratio of α-morroniside to β-morroniside was found to be 2.855∶1 at 25℃. Temperature appeared to be an important factor, which affects the separation result, and a better separation was achieved at a lower temperature.The relative peak height of β-morroniside in the total ion current chromatogram measured with positive ion ESI-TOFmass spectrometer was only a half of that in UVchromatogram.This indicates that β-morroniside is less sensitive to positive ion electrospray ionization than the α-isomer.
    Preface
    Determination of Trace Nucleic Acids Using Neutral Red as the Fluorescent Probe
    LI Wen-You, WU Hui-Ling, HE Xi-Wen, LIANG Hong
    2003, 24(10):  1787-1789. 
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    The fluorescence spectra and binding reaction of neutral red with nucleic acids have been studied.At pH=4.5, a new method for the determination of trace nucleic acids based on fluorescence quenching measurement was established.When 8.0×10-6mol/L NRis employed, the linear ranges of the calibration graphs are 0.08-2.0 μg/mLfor calf thymus DNA(ctDNA), 0.12-2.2 μg/mLfor fish sperm DNA(fsDNA) and 0.30-1.4 μg/mLfor yeast RNA(yRNA), respectively.The corresponding detection limits are 30, 33 and 66ng/mL, respectively.The real samples were analyzed satisfactorily.
    Articles
    A Novel Method for Electrochemical Dual Quartz Crystal Impedance Analysis
    XIE Qing-Ji, ZHANG You-Yu, YANG Xiao-Hui, LI Meng, HE Hong-Mei, YAO Shou-Zhuo
    2003, 24(10):  1790-1792. 
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    Anovel method for simultaneous impedance analyses of two resonating piezoelectric quartz crystals is proposed via the admittance measurements of two crystals in parallel and then nonlinear admittance fitting to an equivalent circuit of two Butterworth-Van Dyke circuits in parallel.Series of sucrose aqueous solutions and copper electro-deposition/stripping in a NH3-(NH4)2SO4buffer were used to test this method, giving that the impedance parameters of each of the parallel crystals reflecting the solution density-viscosity effect or the mass effect were very close to those measured with each single crystal alone.Also, simultaneous impedance measurements at the working and counter electrodes were carried out and discussed.
    A Novel Micro Drop Solvent Extraction Technique Combined with Low Temperature Electrothermal Vaporization ICP-AES for Ultra Trace Element Analysis
    WU Ying-Liang, JIANG Zu-Cheng, HU Bin
    2003, 24(10):  1793-1794. 
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    In this paper, a novel micro drop solvent extraction technique jonied with low temperature ETV-ICP-AES for ultra trace element analysis is reported.The apparatus of micro drop solvent extraction was designed, and preliminary investigation was made for the extraction of ultra trace La by a micro drop of 0.05mol/L PMBP-benzene(2μL).It was found that 500-fold concentration of ultra-trace La in 1m Lsolution was achieved in 0.2 mLof glass chamber by a single micro drop of PMBP-benzene suspended on the tip of a 10μLof microsyringe.The future development of micro drop solvent extraction technique in atomic spectrometry was briefly discussed.
    Studies on QSPR Between GC Retention Indices And Topological Indices of Cycloalkanes by Using Projection Pursuit Method
    DU Yi-Ping, LIANG Yi-Zeng, WANG Wen-Ming
    2003, 24(10):  1795-1797. 
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    Based on the results obtained from projection pursuit, all cycloalkanes investigated show an interesting classification.Thus, a new variable named class distance variable of cycloalkane, which essentially describes information of branch, number of rings in the molecules and homologous series for cycloalkanes, is proposed.With the help of the new variable, both of fitting and prediction accuracy of the regression model can be dramatically improved.
    Field Amplified Sample Injection of Cationic and Anionic Ions at Positive Voltage in Capillary Electrophoresis with Tris(2,2′-bipyridyl)ruthenium(Ⅱ) Electrochemiluminescence Detection System
    LIU Ji-Feng, YANG Xiu-Rong, WANG Er-Kang
    2003, 24(10):  1798-1800. 
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    The field-amplified sample injection behavior of cationic tripropylamine(TPA) and anionic proline(Pro) at a positive voltage in capillary electrophoresis with tris(2,2′-bipyridyl)ruthenium(Ⅱ) electrochemiluminescence(ECL) detection system was studied.In the case of TPA, where the sample solution was prepared in pure water, ECL sensitivity can be improved by 100 times compared to conventional electroinjection method when a positive voltage was applied.Under the same positive voltage condition, anionic Pro prepared in electrolyte solution can also be injected and concentrated in the column when a water plug was injected before sample introduction.The sensitivity and efficiency were enhanced by 10 and 46 times, respectively.The behavior of cationic TPA can be explained by conventional field amplified sample injection(FASItheory.When the ratio of resistivities of sample matrix to that of separation buffer is less than1(γ<<1), the conventional FASItheory can also be used to explain the improved sensitivity and theoretical plates of Pro.The sensitivity, plate, velocity(vep), amplified factor(vep/vep0) and peak variance(σ2) of Pro reach maximum at optimized water plug length and buffer concentration of the sample matrix.
    The Synthesis, Structure and Thermal Rearrangement Reaction of Tetramethyldisilane-bridged Bis(1-phenylcyclohexylcyclopentadienyl)tetracarbonyl Diiron
    SUN Xiu-Li, WANG Bai-Quan, XU Shan-Sheng, ZHOU Xiu-Zhong, WENG Lin-Hong
    2003, 24(10):  1801-1805. 
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    The reaction of 1,2-bis(1-phenylcyclohexylcyclopentadineyl)tetramethyldisilane with Fe(CO)5in refluxing xylene afforded the diiron complex(Me2SiSiMe2)[(1-Ph-c-C6H10C5H3)Fe·(CO)]2(μ-CO)2(2), existing as a mixture of cis and trans isomers(2c and 2t), which were separated by column chromatography.When the two isomers were heated in refluxing xylene, the cis substrate(2c) rearranged to the trans product[Me2Si(1-Ph-c-C6H10C5H3)Fe(CO)2]2(3t), while the trans substrate(2t) yielded the cis product(3c), respectively.This indicates that the rearrangement reaction is stereospecific.The molecular structures of compound 3c and 4t were determined by X-ray diffraction analysis.
    Enzyme-catalyzed Regioselective Synthesis of Novel Raffinose Vinyl Esters
    WU Qi, Lü De-Shui, CHEN Zhi-Chun, YU Guo-Hua, LIN Xian-Fu
    2003, 24(10):  1806-1810. 
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    Sugar esters have recently received increased attention from the viewpoint of renewable resources.Specifically vinyl esters from carbohydrates by enzyme-catalyzed regioselective transformations offer a new family of functional water-soluble monomers for preparation of sugar-based polymers.Here we reported enzyme-catalyzed regioselective synthesis of novel polymerizable raffinose vinyl ester.Transesterification of raffinose with divinyl succinate, divinyl adipate and divinyl sebacate in anhydrous pyridine at 50℃ for6d was catalyzed by an alkaline protease from Bacillus subtilis.Three raffinose vinyl esters with different acyl donor chain lengths were regioselectively synthesized at 55%, 48% and 30% yields, respectively.Characterization of the products by 1HNMR, 13CNMR, and 1H-1Hcorrelation spectroscopy and 1H-13C heteronuclear multiple quantum coherence NMR revealed that the ester was substituted at C-1 position of β-fructofuranose moiety in raffinose.Reaction conditions for the esterification were investigated.Activities of seven commercial enzymes from different sources catalyzing synthesis of raffinose ester were compared.Lipase from porcine pancreas(PPL) and alkaline protease from Bacillus subtilis had high activities.We also studied the effect of temperature and incubation time on raffinose esters synthesis catalyzed by alkaline protease from Bacillus subtilis and found the optimal temperature and reaction time were 50℃ and 6d respectively.
    Studies on Asymmetric Synthesis of 8-O-4′-Neolignan Compounds
    CHEN Xiao-Chuan, REN Xin Feng, PENG Kun, WU Tong-Xing, PAN Xin-Fu
    2003, 24(10):  1811-1814. 
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    Anew method for asymmetric synthesis of 8-O-4′-neolignans has been reported.There are two key steps in this synthesis route.The two chiral centers in 8-O-4′-neolignans are introduced by Sharpless asymmetric dihydroxylation reaction, and the two main sections are coupled to form the frame of 8-O-4′-neolignans by Mitsunobu reaction.Two diastereoisomers of a natural 8-O-4′-neolignan are obtained from protected ferulic alcohol in eight steps by the route, among which threo isomer is the major product.
    Assignment of the Disulfide Bonds of Huwentoxin-Ⅳ by Partial Reduction and Sequence Analysis
    LIU Zhong-Hua, LIANG Song-Ping
    2003, 24(10):  1815-1819. 
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    Huwentoxin-Ⅳ, a neurotoxic peptide from the spider Ornithoctonus huwena, contains three disulfide bonds in a chain of 35 residues.Fully the assignment of disulfide bonds was made by partial reduction and sequence analysis.Huwentoxin-Ⅳ was partially reduced with tris(2-carboxyethyl)-phosphine at 40℃ for 10min at pH=3 and the intermediates were isolated by reversed-phase HPLC.Appropriate isomers containing free thiols were alkylated by adding 100μL of 0.5 mol/Liodoa-cetamide, respectively, following by sequencer analysis, which enabled all three bridges Huwentox-in-Ⅳ to be identified as Cys2-Cys17, Cys9-Cys24 and Cys-Cys31.
    Total Synthesis of (±)-α-Chamigrene-3-one
    WANG Jin-Jun, YIN Jun-Gang, WU Xu-Ran, ZHAO Yan, TAKESHITA Histoshi, MORI Akira, HATSUI Toshihide
    2003, 24(10):  1820-1824. 
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    In this paper, (±)-α-chamigrene-3-one, a spiro-sesquiterpenoid isolated from Marchantia polymorpha, was synthesized via a useful synthon in the synthesis of chamigrene-type sesquiterpenes, i.e., 1,5,5-trimethyl-1-methoxycarbonylspiroundeca -1,8-dien-3-one(6).This precursor was obtained by the de Mayo reaction of terpinolene with methyl 2,4-dioxopentanoate, followed by the retro-aldol rearrangement of the proto-photocyclo-adducts and then Claisen condensation.The title compound was prepared via compound 6 by further transformed by chemical modification at the functional groups
    Design, Synthesis and Application of Polysiloxane-Supported NADH Model
    ZHANG Bao-Lian, ZHU Xiao-Qing, AI Teng, LU Jin-Yong, WANG Peng George, CHENG Jin-Pei
    2003, 24(10):  1825-1829. 
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    Akind of polymer reagentpolysiloxane-supported NADHmodel was designed and synthesized, which can reduce a variety of olefins in excellent yields.The most advantages of this reagent are that(1) separation is easy and(2) the reagent itself can be reused by recycle for many times, which may provide great potential applications in organic synthesis.
    Structural and Optical Properties of MgxZn1-xO Nanofilms Prepared by Sol-gel Method
    LI Jin-Hua, ZHANG Xin-Tong, LIU Yi-Chun, GUO Wei, BAI Yu-Bai, LI Tie-Jin
    2003, 24(10):  1830-1833. 
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    Nanofilms of MgxZn1-xO with different Mg contents were fabricated by sol-gel method.The XRD spectra indicated that the films were hexagonal wurtzite structure with 3-5 nm grain size and the lattice constant of Mg xZn1-xO gradually decreased with increasing Mg content.The UV-Vis absorption spectra showed that the band gap energy increased and the exciton peak had an obvious blue-shift with increasing Mg content.The strong deep level emission demonstrated that oxygen vacancy increased with the content of Mg atoms entering ZnO lattice.To obtain high quality MgxZn1-xO thin films, Mg0.03Zn0.97O film was annealed at 700℃ in oxygen ambient.The UV-Vis absorption spectrum and the PLspectrum demonstrated that high quality films could be obtained by annealing.
    Studies on Charge Transfer Across the Micro-liquid/Liquid Interface Supported at a Double-barrel Micropipette
    CHEN Yong, SU Bin, SHAO Yuan-Hua
    2003, 24(10):  1834-1837. 
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    In this paper, the charge transfer across the micro-liquid/liquid interface supported at the orifice of a double-barrel micropipette, namely, a θ-pipette, is reported.Simple ion transfer(TMA+), facilitated ion transfer(potassium ion transfer facilitated by DB18C6), and electron transfer(ferrocene and ferri/ferrocyanide system) have been investigated by cyclic voltammetry.The experimental results show that a very thin aqueous film, linking both barrels filled with the aqueous solution and the organic solution respectively, can spontaneously be formed on the outer glass surface of such a double-barrel micropipette to construct a micro-liquid/liquid interface, which provides the asymmetry of diffusion field.Such device is demonstrated experimentally which can be employed as one of the simplest electrochemical cells to investigate the charge transfer across the liquid/liquid interface.
    Influence of Thermal Treatment on Structural Phase Transformation of TiO2Nanotubes
    WANG Bao-Yu, GUO Xin-Yong, ZHANG Zhi-Jun, ZHAO Yan-Bao, JIN Zhen-Sheng
    2003, 24(10):  1838-1841. 
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    TiO2nanotubes can only exist in the amorphous state, and the tubulous structure of TiO2nanotubes is destroyed when the crystalline phase of TiO2calcined transforms from amorphous phase into anatase phase.The crystalline phase transformation is the fundamental reason why the tubulous phase strueture is destroyed.It was also found that the long-bar shape crystal columns in rutile were formed when TiO2nanotubes were calcined at 700-800 ℃, but the same case didn′t occur to the raw material how high no matter the temperature for calcining was.The temperatures of phase transformation of TiO2nanotubes from anatase to rutile is lower than that of the raw material calcined at about 350℃. TiO2nanotubes have a very large specific surface area and pole volume.
    Thermodynamic Parameters of Interaction of CsCl with D-Glucose, D-Fructose and D-Sucrose in Water at 298.15K
    JIANG Yu-Cheng, WANG Jian-Ji, ZHUO Ke-Lei, GAO Shi-Yang, XIA Shu-Ping, HU Man-Cheng
    2003, 24(10):  1842-1846. 
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    Electrochemical cells with a potassium ion selectivity electrode(Na-ISE) as a measuring electrode versus a chloride ion selectivity electrode as a reference electrode(Cl-ISE) were used to investigate the interaction of solute-solute and solute-solvent in the CsCl-saccharide(D-glucose, D-fructose and sucrose)-water ternary system at 298.15 K.The activity coefficients of CsCl in saccharides aqueous solutions can be determined through the measurements of electromotive force, and the activity coefficients of saccharides in CsCl aqueous solutions can be evaluated in terms of the Scatchard theory.The McMillan-Mayer theory is employed to relate the excess thermodynamic function with a series of interaction parameters of solute in water so as to obtain the pair Gibbs free energy interaction parameters and salting constant.These parameters have been analyzed by using the model of structural interaction, the effect of hydration of hydroxyl of saccharide and the theory of dispersion energy and the stereostructure of saccharides, which indicates that the interactions of these saccharides with CsCl are controlled mostly by the structure and conformation of their molecules in water.
    An Electrochemistry and in situ STM Studies of Self-assembled Monolayer of Schiff Base N-aete-N on Au(111) Surface
    KONG De-Sheng, CHEN Shen-Hao, WAN Li-Jun, LEI Sheng-Bin
    2003, 24(10):  1847-1851. 
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    The self-assembled monolayer of Schiff base N-aete-Nmolecules on Au(111) in 0.1mol/L HClO4solution has been investigated by electrochemical measurements and in situ STM.Two-dimensional ordered molecular arrays with a (6×7) commensurate structure were observed.The N-aete-Nmolecules are adsorbed on Au(111) in a flat-lying orientation and with a surface concentration of 5.5×10-11mol/cm2.
    Simulative Model and Method of Dynamics Equations Controlling Surface Reaction
    ZHANG Wen-Xia, CAI Mei-Chao, TIAN Feng-Hui, WANG Ze-Xin
    2003, 24(10):  1852-1856. 
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    We introduce a new model about the surface catalytic reaction, namely simulative model and method of dynamics equations controlling surface reaction.In this model, the surface reaction is dominated by dynamics equations that are gained from the law of mass action.The surface reaction is performed in the grid simulation reactor.This simulation model and method are tested by a typical surface catalysis reaction i.e. CO surface-catalytic oxidation.The simulative results are in agreement with those of the experiments.The model is simple and clear because the dynamics equations have no experiential parameter.The model can be generalized to complicated surface-catalytic reactions.
    NaY Zeolite Membrane Prepared by Using Pre-absorbed Nanosized NaY Zeolite Synthesized by Microwave Heating
    CHENG Zhi-Lin, LIN Hai-Qiang, CHAO Zi-Sheng, WAN Hui-Lin
    2003, 24(10):  1857-1861. 
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    Nanosized NaY zeolite was successfully synthesized by microwave heating at an ambient pressure and under reflux.The XRD and SEM results indicate that the resulted NaY zeolite has an average crystal size of 40nm.The compact NaY zeolite membranes consisting of twinborn and polycrystalline crystal were synthesized on a porous alumina substrate by using pre-absorbed nanosized NaY zeolite obtained above and then by being combined with a secondary in situ synthesis.The measuring result for the separation of CO2/N2mixture show that the separating selectivity increased with increasing temperature, and reached a maximum of 4.0 at 140 ℃.
    Ab initio Studies on Keggin Structure Polyoxometalate α-[SiW12O40]4-
    GUO Yuan-Ru, PAN Qing-Jiang, WEI Yong-De, LI Zhong-Hua, ZHOU Bai-Bin
    2003, 24(10):  1862-1864. 
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    The polyoxometalate α-[SiW12O40]4-with the Keggin structure was fully optimized by the ab initio Hartree-Fock method.The optimized geometry parameters of the title compound agree with experimental values.Based on such calculations, the single excited configuration interaction (CIS) method was performed to calculate the excited states related to absorptions.The absorption maximum was calculated at 232nm by using the CIS method and assigned as Od→W and Oc→W charge transfer transition, comparable to the 260nm absorption of α-H4SiW12O40in the experiment.The calculations showed that the distortion of WO6unit can stabilize the whole molecule and the SiO4unit has the quasi-tetrahedral structure.The four W3O13units in the heteropolyacid can possess 3-4 negative charges, which theoretically reveals why the unit with more electrons in the anion is still stable.
    Rate-determining Step of O2-Transportation in the RuO2|Pd|YSZ|Pd deNOxCell
    ZHAO Qin, WANG Xin-Ping, CAI Tian-Xi
    2003, 24(10):  1865-1868. 
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    The properties of the RuO2|M|YSZ|Pd(M=Ag, Pd, Pt, Au) cells for NO decomposition in the presence of excess O2were studied.The applied DC voltage was ranged from1to 4V, and the reaction was proceeded at the temperatures between 500 and 750℃. It is proposed that on the RuO2|Pd|YSZ|Pd cell at 600℃, the transportation of O2-on the Pd|YSZcathode interface is the rate-determining step in the overall O2-ion transportation process in the cell.The RuO2|Pd|YSZ|Pd cell tends to achieve a higher selectivity of the NO electrocatalysis decomposition compared to relative O2ionization at a lower reaction temperature.At 600 ℃, the resistance of O2-transportation on the M|YSZcathode interface increases in the order of Ag<Au<Pd<Pt.By using Ag instead of Pd as the cathode, the current density through the RuO2|M|YSZ|Pd cell was effectively enhanced, which made the RuO2|Ag|YSZ|Pd cell being used at the lower temperature possible and thus the property for NO decomposition was improved.At 500℃, the RuO2|Ag|YSZ|Pd cell shows better properties for NO decomposition, and in the cell the NO conversion reaches 15.3% and the NO decomposition selectivity factor α reaches 13.4.
    Computational Studies on Electrocyclic Reaction Mechanism of 2,3-Diaryl Maleic Anhydrides
    WANG Qi, LIU Yue, LIU Ying
    2003, 24(10):  1869-1872. 
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    Electrocyclic reaction mechanism of 2,3-diaryl maleic anhydrides was studied at B3LYP/6-311+G(d,p)//HF/3-21Glevel.There are two reaction paths for the mechanism.One keeps all the species in trans forms with a strict C2symmetry throughout the reaction path; and the other keeps all the species in cis forms with a strict Cs symmetry.The results are consistent with Woodward-Hoffman principle.The results also support the experimental result that the thermal irreversible property is improved when the hydrogen atoms on the central carbons involved in the bond forming process of the electrocyclic reaction are changed to methyl groups.There is less negative charge on central carbons involved in the electrocyclic reaction for 2,3-bis(2,4-dimethylthiophen-3-yl)maleic anhydride than for 2,3-bis(4-methylthiophen-3-yl)maleic anhydride, conforming the experimental result that the former compound is more stable to oxygen.The LUMO and HOMO energy gaps conform with experimental result that the maximum absorption wavelength for the closed-ring form of bis(methylthiophen-3-yl)maleic anhydride is longer than that of the open-ring form.
    Alkylation of Naphthalene with n-Hexanol over H-type Zeolites
    WEI Chang-Ping, ZHANG Wu-Yang, ZHANG Liang, ZHEN Kai-Ji
    2003, 24(10):  1873-1875. 
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    HY, Hβ and HMzeolites were synthesized and characterized by XRD, NH3-TPD and Py-IR.Selectively catalytic alkylation of naphthalene with n-hexanol to hexyl-naphthalene over the zeolites has been examined.The experimental results show that HY zeolite can be used as a catalyst for the title reaction and shows a higher naphthalene conversion.Higher reaction temperature and longer reaction time are beneficial for the production of β-hexyl-naphthalene over HYzeolite.
    DFT Theoretical Studies on Electronic Spectrum and Nonlinear Optical Properties of Two-dimension Charge Transfer Bis(salicylaldiminato) Schiff Base Zn(Ⅱ) Complexes
    YAN Li-Kai, SU Zhong-Min, KAN Yu-He, QIU Yong-Qing, ZHU Dong-Xia, WANG Yue
    2003, 24(10):  1876-1879. 
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    The geometrical structure of bis(salicylaldiminato) Schiff base compounds and its Zn(Ⅱ) complexes were optimized by using DFT(B3LYP) method at the level of 6-31G(d) basis set.On the basis of it, the NLO coffecients of these systems were calculated by means of finite field(FF) method by introducing external an electronic filed.At the same time, the electronic spectrum of these systems was investigated by TD-DFT method.The results show that the interaction which results from two molecular fragments could obviously increase the values of β and γ. The NLO coefficients of 1a were smaller than its related ligand, but the values of β and γ of complex 2a were higher than its related ligand.It is indicated that Zn(Ⅱ) has a different influence on the completive and local conjugated systems.
    Theoretical Studies on New Silaborate Sandwich Complexes of Cobalt, Rhodium and Iridium
    ZHANG Jian, ZHANG Ming-Yu, SUN Yan-Bo, SUN Jia-Zhong
    2003, 24(10):  1880-1882. 
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    New transition metal sandwich compounds, [(η5-C5H5)M(MeSiB10H10)]-(M=Co, Rh and Ir) have been investigated by using DFT/B3LYP method with relativistic pseudopotentials to study the optimized geometry and the electronic structure.The results obtained are in good agreement with the experimental ones.It is concluded that silaborane cage has stronger coordination abilities and the metal-Si bond length is very short.The electronic structure characters indicate that these sandwich cpmplexes satisfy the 18-electron rule, although they are thermally stable, and they may be photochemically active.
    Flexible Docking of Squamous Cell Carcinoma Antigen 2and Cathepsin-G
    GAO Xue-Feng, HUANG Xu-Ri, SUN Yan-Bo
    2003, 24(10):  1883-1884. 
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    The most softwares for protein-protein docking are regarded as two proteins being rigid, and take no account of the flexibility of proteins, which causes conformation variety of the interface because of interaction of the interface amino acids.On the premise of the rigidity of protein-protein docking, by the method of molecular dynamic simulation, we search the protein-protein interface conformations of the complexes which grounded on the rigid docking.Since the interaction of the amino acid was taken into account, to a certain extent, the complex conformations are more perfect.
    Dynamics Simulation of Rigid Body Movement of the α and α/β Domains of Pyrimidine Nucleoside Phosphorylase
    GAO Xue-Feng, HUANG Xu-Ri, SUN Yan-Bo
    2003, 24(10):  1885-1886. 
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    Pyrimidine nucleoside phosphorylase(PYNP) catalyzes the reversible phosphorolysis of pyrimidines in the nucleotide synthesis salvage pathway.The enzyme has two structure states: non-active opened structure and active closed structure.During change from non-active opened structure to active closed structure, the protein loop connecting domain α to domain α/β becomes bent remarkablely, which results in two domains closed up, and binding pocket reduce obviously.Setting about from the inactive-open X-ray structure, applying the method of molecular dynamic simulation, putting the ligand in the active-pocket, we carry out a dynamic simulation in the CVFF force-field for the entire system.The structures obstained are more approximately to the active-close X-ray structures, it proves that the rigid movement of the domains is arouse by the inducing effect of the ligand molecules.
    Carbosilane Liquid Crystalline Dendrimer Containing Twelve 4-Hexyloxyazobenzene Mesogenic Groups
    ZHANG Qi-Zhen, LIU Jian-Qiang, YIN Xiao-Ying, ZHANG Jing-Zhi, LI Guang, ZHAO Xiao-Guang, JI Yi-Ping
    2003, 24(10):  1887-1891. 
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    The divergent synthesis of a new carbosilane liquid-crystalline(LC) dendrimer(D1) was described.Twelve4-hexyloxyazobenzene groups (M3) were used as mesogenic fragments and attached to its periphery.Structure and properties of D1 were characterized by means of elemental analysis, 1H NMR, IR, UV, MALDI-TOF-MS, polarizing optical micrograph, DSC and WAXD.D1 is a nematic liquid crystal, which is the same as M3.The mesomorphic behaviour of the dendrimer depends on that of the mesogenic units.Phase behavior of D1 is K92N126I124N78K.m.p.of D1 is 24-30 ℃ lower than that of M3, its clearing temperature is 6-8 ℃ higher than that of M3 and its mesophase region is 30~38 ℃ wider than that of M3.The clearing enthalpy of D1 accords with the value that is commonly found for n-i phase transition in LCand LCpolymers.This may be due to the deformation of branched dendrimer D1 which can be change to fit into the anisotropic LC phase structure.Eight extinguished brushes emanating from a stationary point are observed, corresponding to the high-strength disclination of S=+2 of dendrimer.
    Synthesis of PAn/CA Composite Membrane by in-situ Permeating Ploymerization
    DU Jun, ZHENG Chan-Juan, TAO Chang-Yuan
    2003, 24(10):  1892-1895. 
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    The preparation of PAn/CA composite conductive membrane by in-situ permeating chemical polymerization was introduced in this paper.By this method, polyaniline was synthesized onto the pore wall of the CAmicroporous membrane.The influence of preparing conditions on the conductivity and apparent selectivity of CO2/O2was investigated.The pore size and distribution of the resulting membrane were evaluated by the method based on bubble pressure and liquid permeation.SEM, FTIRwere employed to characterize the composite membrane.The results showed that the pore size of PAn/CA composite membrane decreased and the pore size distribution became narrow, and the apparent selectivity of CO2/O2were improved.
    Studies on Sorption Property Forwards Caffeine and Theophylline by Phenolic Resin
    WANG Zhong, SHI Zuo-Qing, WANG Rui-Fang
    2003, 24(10):  1896-1901. 
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    The sorption of phenolic resin adsorbents JDW-2(made by ourself) and Duolite S-761 for caffeine and theophylline was studied under static and dymanic conditions in this paper.The experimental results show that the sorption properties of JDW-2 for caffeine and theophylline are superior to that of Duolite S-761. The surface area, the moisture retention and phenolic hydroxyl amount of adsorbents jointly influenced the sorption.Though JDW-2 has a lower surface area than Duolite S-761, the former sorbents has a higher moisture retention(42%) and phenolic hydroxyl amount(3.72 mmol/g) as compared to that of the latter.Finally, we have found that the sorption of caffeine by JDW-2 is faster than that by Duolite S-761 under static conditions, the saturation sorption capacity of JDW-2 for caffeine and theophylline is 246 and 127mg/g dried resin respectively, and that of Duolite S-761 is only 121 and 53 mg/g respectively.Asemi-empirical rate equation adequately fit the sorption rate data of caffeine in the initial period.The sorption mechanism of JDW-2 and Duolite S-761 resins for caffeine was confirmed by the particle-diffusion control of the sorption process in the initial period.The equilibrium sorption data for phenolic resin sorbents/caffeine(or theophylline) systems showed good agreement with the Langmuir isotherm equation.The correlation coefficients are bigger than 0.99.The sorption of caffeine and theophylline therefore is monomolecular sorption.It is clear that the volume of 1mol/Lhydrochloric acid in 40% aqueous methanol at the rate of desorption 1.5BV/h for removing 88% and 93% all the caffeine adsorbed on JDW-2 are 4 and 5BV(bed volume) respectively, and that of 1mol/Lhydrochloric acid in 80% aqueous methanol at the rate of desorption 1.5BV/h for removing 91% and 96% all the theophylline adsorbed on JDW-2 are 3 and 4 BVrespectively under dynamic conditions, which show that phenolic resin adsorbent possesses excellent desorption performance.It is very good to use 1mol/Lhydrochloric acid in 40%(or 80%) aqueous methanol as composite desorption solvent stripping caffeine(or theophylline) from JDW-2.
    Rate Model of Vinylidene Chloride Suspension Polymerization
    Lü Qun, TAO Chun-Yuan, WENG Zhi-Xue, HUANG Zhi-Ming
    2003, 24(10):  1902-1906. 
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    The kinetics of suspension polymerization of vinylidene chloride was studied by experiments.Similarities and differences of the kinetics behavior were analyzed for the polymerizations of vinylidene chloride and vinyl chloride.Based on the assumption that the polymerization of vinylidene chloride includes the reactions in monomer phase and on the interface between liquid and solid phases, a kinetic rate model was proposed for the heterogeneous polymerization of vinylidene chloride.The conversion value calculated by the model is consistent well with the experimental results of vinylidene chloride suspension polymerization nearly over the entire conversion range.
    Studies on the Exfoliating Mechanism of Montorillonite Slice Layer in Nylon 1212/Montorillonite System Under Shear-fluidic Field
    WANG Gang, ZHOU Chi-Xing, LI Jian, WU Zeng-Gang
    2003, 24(10):  1907-1910. 
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    There is a critical value(velocity gradient Xviscosity) at which the shear-induced plane compresion causes the slices of montmorillonite(MMT) to buckle and produces a cuneate space between the outside slice and the crystallite during the melt intercalation.The outest slice can be broken when it bends exceed the minimal curvature radius and yields exfoliation further.The appropriate intensity of flow is the key point of getting suitable slice configuration in the nano-composition process.
    Synthesis, Characterization and Property Studies on a Methyl-substituted Poly(ether ether ketone) and Its Copolymers
    LI Hui, ZHOU Hong-Wei, CHEN Chun-Hai, WU Zhong-Wen, ZHANG Rong-Ben, YU Shu-Yan
    2003, 24(10):  1911-1914. 
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    Anovel soluble methyl-substituted poly(ether ether ketone) PETMDEK was synthesized for the first time by aromatic nucleophilic substitution polycondensation.Aseries of random copolymers PETMDEK-PEDEK with different compositions were prepared and their properties were studied.The copolymers exhibit changes from crystals→liquid crystals→crystals→amorphous solid transitions with the increase of the content of PETMDEK.The copolymers also change from soluble substance to insoluble one.The thermotropic liquid crystalline behavior of 20% PETMDEK-PEDEK copolymer was characterized by DSC and PLM.
    Studies on Electrochemical and Electrocatalytic Properties of Functional Poly-2,5-dimethoxyaniline Membrane
    XU Yi-Ting, HE Yun-You, DAI Li-Zong, Rakotoartsoa Tahina, Gal Jean-Yves, WU Hui-Huang
    2003, 24(10):  1915-1919. 
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    Electrochemical activity of poly-2,5-dimethoxyaniline(PDMAn) is similar to parent polyaniline because of two symmetric substituted groups.Three oxidation states of PDM An can transform reversibly, known as the completely reduced leucoemeraldine(L), intermediate emeraldine(E) and the fully oxidized pernigraniline(P).In voltammograms, the L/E, E/P transformation peaks are located at 0.19 and 0.51V, respectively.Doping polymer and intrinsic polymer follow the redox transformation as LEHP and LHEHP separately.And E/P transformation peak shifts to lower potential by increasing pHvalue.In de-aerated solution the platinized polymer has an evidently catalytic activity on isopropanol oxidation.Furthermore the oxidative current enhances with increasing potential cycling numbers, whereas it decreases for platinized Pt electrode.The Pt particles not only highly disperse in PDMAn membrane, but also interact with PDMAn, resulting in changing their geometric structure and the electron properties of that metal.It is illustrated that as a catalytic system with a high catalytic and anti-poisoning activity, platinized PDMAn membrane electrode will also catalyze isopropanol oxidation in pH=4.7 buffer solution.It is pointed that PDMAn will degrade after preservation in air for three years.
    Synthesis of PMA/ZnAl-LDH Intercalation Nanocomposite by in situ Polymerization and Its Morphology
    CHEN Wei, QU Bao-Jun, FENG Li
    2003, 24(10):  1920-1922. 
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    Apoly(methyl acrylate)(PMA)/ZnAl layered double hydroxide(ZnAl-LDH) intercalation nanocomposite is synthesized by in situ polymerization of methyl acrylate with ogano-modified ZnAl-LDH(O-ZnAl-LDH).Its structure and morphology are confirmed by X-ray diffraction(XRD) and transmission electron microscopy(TEM) image.The d001of O-ZnAl-LDHis expanded to 2.85 nm after polymerization from 2.63 nm, which indicates the intercalation of PMAchains into the galleries of O-ZnAl-LDH.The (001) diffraction of PMA/ZnAl-LDH nanocomposite is broad due to the exfoliation of some O-ZnAl-LDH layers.The TEM image shows that the most of the layers of O-ZnAl-LDH are stacked with a distance of about 3 nm while some of them are exfoliated and dispersed disorderly in the PMA matrix.
    Studies on Crystallization Behavior of Polypropylene Catalloys
    LIN Zhong-Hua, PENG Mao, ZHENG Qiang
    2003, 24(10):  1923-1925. 
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    Non-isothermal crystallization behavior of molten polypropylene catalloys(PP-c) was studied by using differential scanning calorimetry(DSC).Besides, crystallization process and spherulite morphology were observed through polarized optical microscopy.Compared with pure polypropylene(PP), the crystallization peak temperature(tcp) of PP-c shifted to a higher temperature, and the value of tcp became bigger with the increase of ethylene component in PP-c.The spherulitic geometrical dimension of PP-c decreased distinctly, and the number of spherulite augmented obviously.It is believed that the ethylene component acts as the heterogeneous nucleation agent in PP-c.
    Monte Carlo Simulations for the Very Beginning of RAFT Seeded Emulsion Polymerization
    LUO Ying-Wu
    2003, 24(10):  1926-1928. 
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    Monte Carlo simulation technique was used to simulate the scenarios of the very beginning of a particle in RAFT seeded emulsion polymerization.It was first found that by introducing a high reactive RAFT agent, a large number of free radical need to be captured by the particle before polymerization starts up.The phenomenon was ascribed to the high reactivity of RAFT agent and fast exit of fragmented group of the original RAFT agent.The simulations could be successfully used to explain an unexpected long induction period and polymerization retardation reported.The results of this study will be of particular use in understanding and design of RAFT emulsion polymerization.