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    24 April 1998, Volume 19 Issue 4
    Articles
    Conformation Equilibrium of Iron(Ⅲ)-metal-free Porphyrin Dimers and Its Effect on Catalytic Activity for Cyclohexane Hydroxylation
    REN Qi-Zhi, HUANG Jin-Wang, LIU Zhan-Liang, JI Liang-Nian 
    1998, 19(4):  497-501. 
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    A series of iron(Ⅲ)-metal-free porphyrin dimers covalently linked with -O(CH2)n O- chain( n =2~5) have been synthesized and characterized. By using UV-Visible spectra, an equilibrium of two different conformations of porphyrin dimers, open and closed, in chloroform solution has been observed for the first time. The intensity of adsorption band 680 nm may be related to the conformation equilibrium, the longer the length of the alkoxy chain, the stronger the intensity of band 680 nm is present. As a new model catalytic system of cytochrome P450, all these dimers have higher catalytic activities than the corresponding mono iron(Ⅲ) porphyrin, and their catalytic activities increase gradually with the increase of the length of flexible chain. The higher catalytic activities may be related to the steric hindrance and intramolecular electron transfer of the porphyrin dimers caused by the conformation equilibrium.
    Synthesis of (C26 H40 N2O4)[Ln(NO3)5H2O] and Crystal Structure of (C26 H40 N2O4)[Eu(NO3)5H2O]
    CHEN Zhao-Hui, JIN Lin-Pei, GUO Jian-Quan
    1998, 19(4):  502-506. 
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    Four novel rare earth compounds H2L[Ln(NO3)5H2O](Ln=Pr,Nd,Sm,Eu; L= C26 H38 N2O4 : 1,7,10,16-tetraoxa-4,13-diaza-N, N ′-dibenzyl-cyclooctadecane) were synthesized and characterized by elemental analysis and IR. The crystal structure of C26 H40 N2O4[Eu·(NO3)5H2O] was determined by X-ray analysis. The crystal belongs to triclinic, P1 space group with cell dimensions: a =0.9100(4) nm, b =1.3560(3) nm, c =1.6463(4) nm; α =68.62(2)°, β =74.84(3)°, γ =87.50 (2)°; Z =2. The central europium ion is bonded to ten oxygen atoms from the five nitrate groups and one oxygen atom from a water molecule. Coordination number is 11. 1,7,10,16-Tetraoxa-4,13-diaza-N, N ′-dibenzyl cyclo octadecane is not bonded to the europium ion.
    Synthesis of Rare Earth Ultrafine Powders by Spray Pyrolysis (Ⅰ) Particle Morphology and Formation Mechanism of Y2O3 Powder
    ZHAO Xin-Yu, ZHANG Yu, GU Hong-Chen, GAO Wei
    1998, 19(4):  507-510. 
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    Spray pyrolysis is a promising process for mass-production of high quality ultrafine powder. However, studies for preparation of rare earth powder by spray pyrolysis are relatively few until now. In this study the spray pyrolysis process was used to prepare Y2O3 ultrafine powder. First, the thermal properties of precursor Y(NO3)3·6H2O were determined by DTAand TG. It was indicated that Y(NO3)3·6H2Owas fully decomposed into Y2O3 above 580 ℃ at a heating rate 20 ℃/min. Based on the thermal analysis results, pure cubic phase Y2O3 powders with uniform size of 0.50~1.50 μm were prepared by spray pyrolysis from aqueous solution of Y(NO3)3·6H2O. The particle size can be adjusted by controlling the operation parameters such as droplet size and concentration of precursor solution. It was proposed that the formation mechanism of Y2O3 powders conforms with One-Droplet One-Particle mechanism(ODOP). This spray pyrolysis process can also be adapted to prepare other kinds of rare earth powders.
    Synthesis and Characterization of Amino Acid Bridged Novel Chiral Zinc Porphyrin Dimer
    LIU Hai-Yang, HUANG Jin-Wang, TIAN Xuan, HU Xin-Ming, JI Liang-Nian
    1998, 19(4):  511-513. 
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    Novel phenylalanine bridged dimeric porphyrin was synthesized by the reaction of 5-[o-(2-bromo-1-ethoxyl)]-10,15,20-triphenylporphyrin and amino acid in DMF in the presence of phase transfer catalyst BTEACin about 10%—15% yields. Zinc complexes derived exhibit strong split induced circular dichroism(ICD) at the soret absorption region and weak single peak ICD at the Qabsorption. While the corresponding free base porphyrin exhibits no obvious ICD. L-and D-phenylalanine bridged zinc porphyrin dimer constituted pairs of enantiomers. These complexes can be used as good model compounds for the investigation of induced circular dichroism of porphyrin occurring in natural systems.
    Studies on Extraction and Mass Transfer of Samarium and Neodymium in Hollow Fiber Membrane(HFM) with HEH/EHP
    ZHANG Feng-Jun, LI De-Qian, WU Yong-Lie, CHENG Yong-Jie
    1998, 19(4):  514-516. 
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    The membranes of polyvinylidene fluoride, which were synthesized by our laboratory, were used to study the transfer and extraction performances of Nd(Ⅲ) and Sm(Ⅲ) with the extraction system of HEH/EHP-kerosene. The results show that the membrane material was suitable to the study on membrane extraction, and could offer a good transfer performance in the membrane construction parameters selected. The extraction reaction in the membrane module was the same as that in liquid liquid process. HEH/EHPammoniated for increasing the mass transfer coefficient was almost the same with increasing the concentration of HEH/EHP, and H+ was still transferred first at higher pHrange of feed solution when HEH/EHP was ammoniated. The controlling model of the membrane extraction process was the diffusion model accompanied by interfacial reaction. The controlling function of interfacial reaction would increase gradually with the increasing of the membrane pore size. The mass transfer coefficient increased when extraction and stripping were carried out simultaneously.
    Syntheses and Structures of Na2[Zn(ida)2]·7H2O and Na4[Hg(nta)2]·7H2O
    WANG Jun, ZHANG Wei-Qun, ZHANG Xiang-Dong, XING Yan, LIN Yong-Hua, JIA Heng-Qing
    1998, 19(4):  517-519. 
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    The title complexes were synthesized and the crystal structures of their salts were determined by single crystal X-ray structure analyses. Na2[Zn(ida)2]·7H2O: Triclinic, P1, a =0.5234(2) nm, b =0.89710(10) nm, c =1.06910(10) nm, α =85.910(10)°, β = 76.380(10)°, γ =83.52(2)°, V =0.4842(2) nm3, Z =1. The complex anion [Zn(ida)2]2- has a pseudo octahedral structure in which the two Natoms are in a trans configuration. Na4[Hg(nta)2] ·7H2O: Monoclinic, Cc, a =1.7980(4) nm, b =0.8929(2) nm, c = 1.5754(2) nm, β =92.78(3)°, V =2.5262(9) nm3, Z =4. The complex anion [Hg(nta)2]4- has a pseudo bicapped octahedral structure in which the two Natoms are in a trans configuration.
    On-line Coupling Technique of Packed Capillary High Performance Liquid Chromatography with Capillary Gas Chromatography
    JIANG Tao, GUAN Ya-Feng 
    1998, 19(4):  520-525. 
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    An on-line coupling system of packed capillary high performance liquid chromatography(PC-HPLC) with capillary gas chromatography(CGC) has been developed. The interface consists of a 10-port valve and a multi-position valve, which cuts and stores fractions continuously from PC-HPLC, and transfers them into the GCcolumn separately without sample loss. An auxiliary solvent loop was used to wash the sample loop of the interface. The dead volume that cannot be washed is less than 0.1μL. The factors that affect the performance of the system were investigated in detail. The error of the reproducibility of the system is less than 1.5% relative standard deviation. The analysis of diesel fuel and transformer oil were demonstrated, which shows the strong separation power and application potential of this system for complex compounds.
    Photoacoustic and Fluorenscence Studies of Rare Earth β-Diketone Complexes Doped Silica Gel
    SU Qing-De, GAO Kun-Xiu, TAO Ye, ZHAO Gui-Wen
    1998, 19(4):  526-529. 
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    A series of rare earth β-diketone complexes doped silica gel have been prepared by Sol-Gel technique. The photoacoustic and fluorescence spectra of these gel have been measured. Compared with the solid complexes, emission peaks of these doped silica gel show redshift while photoacoustic absorption peaks blueshift. The intramolecular energy transfer processes of Eu-β-diketones doped silica gel have been studied.
    Artificial Neural Network Applied to Diagnosis of Lung Cancer
    ZHANG Zhuo-Yong, LIU Si-Dong, DING Bao-Jun, REN Yu-Lin, CHEN Hang-Ting, ZENG Xian-Jin
    1998, 19(4):  530-533. 
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    Artificial neural network(ANN) approach was applied to classification of normal persons and lung cancer patients based on the metal content of hair and serum samples obtained by inductively coupled plasma atomic emission spectrometry(ICP-AES) for the two groups. This method was verified with independent prediction samples and can be used as an aiding means of the diagnosis of lung cancer. The case of predictive classification with one element missing in the prediction samples was studied in details. The significance of elements in hair and serum samples for classification prediction was also investigated.
    A Study on Analytical Performance of THGF
    HE Zhi-Rong, CHEN Jiang-Han, HE Hua-Kun
    1998, 19(4):  534-537. 
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    The isothermal and analytical performance of transversely heated graphite furnace(THGF) have been studied and discussed theoretically and experimentally, and was compared with Massmann-type graphite furnace. The results showed that THGF has better isothermal performance than Massmann-type furnace, the former has shorter atomization time, shorter occupied time of atomic absorption signal, lower atomization temperature and m 0 value.
    Preparation of Chiral Stationary Phases Coated Using Cellulose Derivatives and Study of Chiral Resolution in HPLC
    HOU Jing-Guo, ZHOU Hong-Ying, JIANG Sheng-Xiang, ZHOU Zhi-Qiang, CHEN Li-Ren, OU Qing-Yu
    1998, 19(4):  538-542. 
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    Optical resolution of a range of racemic compounds was investigated using cellulose tribenzate and trisphenylcarbamate coated onto a small-partial spherical organosilane modified silica. The influence on chiral discrimination of factors such as coated loadings and mobile phase was performed. The loadings of 15% on the support gave the best results. The regioselectivity of an asymmetric hydroesterification of styrene was determined by HPLCusing a chiral stationary phase(CTPC-CSP). Asatisfactory result had been obtained on CTPCchiral column with n-hexane/2-propanol(98/2 in volume ratio) as mobile phase.
    Studies on the Effects of Five Kinds of Divalent Metal Ions on LDH Activity by Single Sweep Voltammetry
    WANG Xun-Qing, GAO Xiao-Xia 
    1998, 19(4):  543-546. 
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    In this paper the effects of five kinds of divalent metal ions on LDH activity were studied. The results showed that Zn 2+ and Ca 2+ do not affect LDH activity while Mn 2+ exerted inhibitory effect. At low concentrations, Cu 2+ and Mg 2+ slightly stimulate LDH activity. From the binding model of ternary complex, it could be concluded that LDH is a non-metallic enzyme and Zn 2+ did not play a catalytic role in LDH. The different effects of Cu 2+, Mg 2+, Mn 2+ and Ca 2+ ions were also discussed.
    Investigation on Application of Wavelet Transform in Recovering Useful Information from Oscillographic Signal
    ZHONG Hong-Bo, ZHENG Jian-Bin, PAN Zhong-Xiao, ZHANG Mao-Sen, GAO Hong
    1998, 19(4):  547-549. 
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    Application of wavelet transform in recovering useful information from different kinds of oscillographic chronopotentiometric signal was studied in this paper. Effects of the transform frequency, white noise and kinds of wavelet function and the oscillographic signal on the transform results are discussed. In above-mentioned factor, the noise and the transform frequency are two main factors of the influence. Experimental result for the former indicated that for the noise and favorable peak shape a signa-to-noise ratio of 3 can be tolerated at the 5% error level, which means that a significant reduction in the detection limit can be obtained in comparison with the classical signal-processing methods. And the findings of the latter showed that peak height caused by depolarizer depends on decomposition frequency for the signal, and the optimum choice of this frequency, in turn, depends on kinds of the signal. For dE /dt-t signal, three frequency of the transform can obtain the best peak shape and the largest peak height. Thus, compared with Fourier transform, it is easy to recover useful information from the oscillographic signal with noise and background signal caused by base solution.
    Studies of Stability of Co—N Bond on the VB12 Model Molecule
    FENG Ya-Qing, ZHANG Xiao-Dong, ZHANG Wei-Hong
    1998, 19(4):  550-554. 
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    Vitamin B12 model molecule, dicyano hexamethyl-N-(3-imidazoly)propylamido cobyrinates perchlorate 4b—4f were synthesized and treated with acidic buffers in methanol, and the ring was opened to give compounds 5b—5f. UV-Vis spectra were determined in buffers with different pHvalues, and equilibrium constants of Co—N bonds were calculated. The strength of coordination bonds between Natom in the side chain of cobyrinates and Co atom was in the order of 4d>4f>4c>4e>4b.
    The Synthesis and Biological Activity of N-(4,6-Dimethoxy-2-pyrimidinyl)-N'-phosphoryl Urea Derivatives
    ZHAO Guo-Feng, YANG Hua-Zheng, WANG Ling-Xiu
    1998, 19(4):  555-559. 
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    In this paper N-(4,6-dimethoxY-2-pyrimidinyl)-N'-dichloro-phosphoryl urea(Ⅰ) was synthesized by addition reaction of dichloro phosphoryl isocyanate with 4,6-dimethoxY-2-aminopyrimidine. Compound Ⅰ reacted with two equivalents of amines or alcohols to obtain symmetric disubstituted phosphoryl urea derivatives Ⅱa_Ⅱi, and reacted with one equivalent of amines to give monochlorophosphoryl ureas Ⅲa_Ⅲe which reacted with one equivalent of alcohols to obtain asymmetric disubstituted phosphoryl urea derivatives Ⅳa_ Ⅳg. The biological tests indicated that compounds Ⅱ, Ⅲ and Ⅳ showed herbicidal activities.
    Structures and Mesomorphic Properties of Monoarmed Crown Ether Liquid Crystals
    JIANG Qing, XIE Ming-Gui, LI Long-Zhang, RUAN Ji-Wu, WANG Xue-Jun
    1998, 19(4):  560-563. 
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    Four monoarmed crown ether liquid crystals were designed and synthesized. The relationship between the properties of liquid crystal and central bridge bond that contact the crown ether and lipophilic structural unit was investigated. The melting point of crown ether liquid crystals was changed a little by variation central bridged bond. The various central bridged bonds change the stability of liquid crystalline phase. The order of clearing point is _N=CH_ > _N=N_ > _O_CO_ > _HN_CO_.
    A Preliminary Study on Expression of Fibroin C Subunit as a Fusion Protein in E. Coli
    LI Hong-Jie, CAI Zai-Sheng, SHI Hua-Fang, YU Tong-Yin, HUANG Wei-Da 
    1998, 19(4):  564-567. 
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    The structural gene of fibroin Csubunit(i.e. fibroin light chain, FL) was amplified by polymerase chain reaction(PCR) from pFL18 plasmid, which carries a cDNAclone of fibroin Csubunit. The PCR product was cloned on fusion protein expression vector pRIT2T, and was expressed in the E. Coli strain P2392. SDS-polyacrylamide gel electrophoresis(SDS-PAGE) and immunoblotting were carried out to verify the expression of protein Afibroin Csubunit fusion protein.
    Synthesis of Novel Chiral Copper(Ⅱ) Complexes and Their Application on Asymmetric Cyclopropanation of Olefins
    LIU Shang-Zhong, CHEN Fu-Heng
    1998, 19(4):  568-571. 
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    Four chiral copper(Ⅱ) complexes derived from two novel chiral compounds (S)-(-)-α-substituted-2-hydroxy-5-methylbenzylamine were synthesized. All the complexes were used as catalysts in the asymmetric cyclopropanation reaction of styrene, 1,1-diphenylethylene and 2,5-dimethyl-2,4-hexadiene. It is found that the more effective catalysts are related to complexes with ligands prepared from optically active amine and 2-hydroxy-1-naphthylaldehyde.
    One Pot Synthesis and Biological Activity of 2,5-Dipyrazolyl-1,3,4-oxadiazoles
    CHEN Han-Song, LI Zheng-Ming 
    1998, 19(4):  572-573. 
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    2,5-Dipyrazolyl-1,3,4-oxadiazoles were synthesized from 5-pyrazole formic acid and its hydrazide by one pot synthetic method in the presence of phosphorus oxychloride. The method shortened synthetic route and simplified experimental operation. The preliminary biological activity tests showed that compound 3b has fungicidal and herbicidal activity.
    Thermoregulated Phase transfer Ligands and Catalysis(Ⅴ) ——Synthesis and Catalytic Properties of Mono and Di p polyoxyethylene Substituted Triphenylphosphines
    ZHENG Xiao-Lai, CHEN Rui-Fang, JIN Zi-Lin
    1998, 19(4):  574-576. 
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    Mono- and di-p-polyoxyethylene substituted triphenylphosphines(1) were prepared by the ethoxylation of diphenyl(4-hydroxyphenyl)phosphine and phenyldi(4-hydroxyphenyl)phosphine. RhCl3/1 complexes have desirable catalytic properties in aqueous/organic biphasic hydroformylation of 1-hexene, with a conversion up to 95%, and can be reused for 5 times without loss in activity. Since ligands 1 possess inverse temperature-dependent solubility in water, the hydroformylation has undergone an interesting process of thermoregulated phase-transfer catalysis, in which the catalyst transfers into the organic phase to catalyze the reaction at a higher temperature, and returns to the aqueous phase to be separated from the product at a lower temperature after the reaction is completed.
    Synthesis of 3-Acylhydrazino-5-(2,4-dichlorophenyl)-1,3,4-oxadiazole and Studies on Their Cyclization
    FENG Xiao-Ming, HE Xun, JIANG Yao-Zhong
    1998, 19(4):  577-579. 
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    Fourteen new 2-acylhydrazino-5-(2,4-dichlorophenyl)-1,3,4-oxadiazoles were prepared by nucleophilic displacement of acylhydrazine at the 2-position of 2-methylsulfonyl-5-(2,4-dichlorophenyl)-1,3,4-oxadiazole . Fourteen new 3-substituted-6-(2,4-dichloro-phenyl)-S-triazolo-1,3,4-oxadiazoles were obtained by treating 2-acylhydrazino-5-(2,4-dichloro phenyl)-1,3,4-oxadiazoles with K2CO3 solution. The structures of new compounds were determined by elementary and spectral analyses. All the new compounds showed a significant antibacterial activity.
    The Synthesis and Bioactivity of Some Novel Pyrethroids
    ZHENG Guo-Jun, ZHOU Rong-Can
    1998, 19(4):  580-582. 
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    In order to search for the highly efficient and low toxic pyrethroids, sixteen novel compounds were synthesized by reaction of 1-aryloxy-4-chloro-2-butyne with pyrethroid acid. Their structures were confirmed by 1H NMR, IR, elementary analysis or MS. The preliminary bioassays of all compounds indicated that four of them, B1, B2, B4 and B6, showed high insecticidal activity to mosquito larva.
    Theoretical Study on Secondary Chemical Bond in Organic Compound(Ⅳ) The Secondary Chemical Bonds in Copper(Ⅱ) Complex of 4,8-(8-Methylquinolyl)-1,4,8,11-tetraazacyclotetradecane
    YUAN Man-Xue, YANG Da-Jun, SHI Jing, BU Xian-He, LAI Cheng-Ming
    1998, 19(4):  583-585. 
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    According to the data of X-ray crystal structure of CuL2[14]-2qu, we have used the calculating methods of molecular mechanics, quantum chemistry CNDO/2 and molecular electrostatic potential. The results show that there are the secondary chemical bonds between Cu(Ⅱ) and Nof quinoline ring in the coordinate compound(CuL2[14]-2qu). The existance of secondary chemical bonnds makes the two quinoline pendants on the different sides of the macrocycle plane and the three atoms N11—Cu—N12 nearly co linear.
    Theoretical Study on the Thermal Isomerization from 1,2-Butadiene to 2-Butyne
    LEI Ming, QIAN Ying, WANG Yan, FENG Wen-Lin
    1998, 19(4):  586-590. 
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    Ab initio UHF/631G** method was employed to study the reaction mechanisms of the thermal isomerization from 1,2-butadiene to 2-butyne, which involves two reaction pathways. The geometries of the reactant, the intermediates, the transition states and the product for the reaction are optimized by Berry technique. Each transition states was further confirmed by having one and only one imaginary vibrational frequency. In addition, the zero point energies were calculated for correcting the energies of stationary points. As an important intermediate, 1-methylcyclopropene play a significant part in the isomerization. The calculated activation energy of the pathway proceeding in multisteps via 1-methylcycloproene etc is 28683 kJ/mol, which is in good agreement with arrhenius value of 26460 kJ/mol. The results indicate that the thermal rearrangement of 1,2-butadiene to 2-butyne via 1-methyl-cyclopropene is more energetically favourable than that via two-step hydrogen-shift process.
    Photo-electric Properties of Ordered Films of Polyvinylcarbazole and Arachidic Acid
    ZHANG Wei-Feng, GUO Hong, MA Guo-Hong, HUANG Ya-Bin, DU Zu-Liang
    1998, 19(4):  591-594. 
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    The solid state films of photo-conducting PVKmaterial were prapared by means of LBtechnique. The fluorescence spectra showed that strong excimer emission of PVKappeared in the films, and the surface photovoltaic spectra revealed that PVKfilms/p-Si have a significant surface photovoltaic effect.
    The Electronic Structure of the Carbon Nanotubes with the Cages as the Caps
    LI Qian-Shu, ZHANG Xiao-Dong, ZHU He-Sun
    1998, 19(4):  595-597. 
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    Similar to the modified carbon nanotubes structure constructed by Hamada, we also constructed some simple carbon nanotubes models with the carbon element cages as the caps, which have C5/C3 symmetry. Under the Hückel approximation, the π electronic structures of the carbon nanotube models were calculated with the help of group reducible theorem. From these calculated results, some conclusions could be drawn: (1) For all carbon nanotube models, the average single electronic energy increases with increasing the numbers of the hexagonal layers. This implies that the longer carbon nanotubes might be potential molecules. Compared with the isolated C55 and C54 and the open carbon nanotubes, those models molecules are potential molecules. (2) For the molecules with subgraphs e, h and h, the number of bonding orbital is equal to that of antibonding orbital. So they are stable closed shell structure. (3) For the molecule with subgraphs a, b, c, d, f and g, the different values between the numbers of bonding and antibonding orbitals are 2,4,6,2,4 and 4, respectively. The molecules with subgraphs f also have two nonbonding orbitals. Therefore these molecules could form neutral or anion molecules. (4) The molecules with subgraphs i( k =3, 6 and 9), i'( k =1, 4, 7 and 10) and j might form cation structure as their HOMOs are nonbonding orbital. (5) The molecules with subgraphs i'( k =1, 4, 7 and 10) and j'could form cation, and those molecules with subgraphs g and d could form anion, therefore it seems that the formers could interact with the latters to form two dimensional and three-dimensional systems constructed by Hamada.
    The Calculation of Thermodynamic Equilibrium Constant in CuSO4-aminate P507-n-C6H14 System
    CUI Dan, DUAN Shu-Hong, SUN Tie
    1998, 19(4):  598-602. 
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    The thermodynamic equilibrium model of acidic phosphoric extractant and metal system was studied with thermodynamic method. The activity coefficients of the components such as water, C6H14, extractant in organic phase can be calculated according to the thermodynamic relation, and γCu2+ can be estimated according to Pitzer's equation. The experimental data can be used to correlate and solved on computer. The results showed that the thermodynamic equilibrium constant Kwas in the range of 1.62×10~7 ~5.26×10-7 and the activity coefficients of the components were achieved.
    Application of Geminal N-Electron Basis Set to LiH Molecule
    WANG Guo-Li, LIU Jing-Yao, SUN Chia-Chung
    1998, 19(4):  603-605. 
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    By means of the geminal N-electron basis set, the LiHmolecule is calculated, where the ab initio STO-6G basis set has been used. The calculated results show that for spin singlet and triplet states of LiHmolecule we can accurate the results via an adequate choice of a small number of the geminal N-electron bases without using the full geminal N-electron basis set.
    Selective Catalytic Reduction of NO with C3H6 over CuCl/ZSM-5 Zeolites Prepared by Disperse Method
    JIA Ming-Jun, ZHANG Wen-Xiang, XIAO Feng-Shou, WU Tong-Hao, SUN Tie
    1998, 19(4):  606-608. 
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    The selective catalytic reduction of nitrogen monooxide with propene in the presence of oxygen has been studied over CuCl/ZSM 5 prepared by the disperse method. It was found that the catalytic properties were changed obviously with the change of the type of parent zeolite, and the conversion of NO on CuCl/H ZSM-5 was much higher than that on Cu/Na ZSM-5. For CuCl/H-ZSM-5, the activity was increased with the increasing of copper amount. The activity of CuCl/H-ZSM-5(Cu amount>4%) was higher than that of ion-exchanged Cu-ZSM-5 zeolites at 573K.
    In Situ Studies of Highly Oriented Zn-Ni Alloy Electroplating by Using ECSTM
    XIE Zhao-Xiong, MAO Bing-Wei, YANG Fang-Zu, ZHUO Xiang-Dong, MU Ji-Qian, TIAN Zhao-Wu
    1998, 19(4):  609-612. 
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    Based on a very effective “two-step-coating” method developed for ECSTM tip preparation, highly oriented Zn-Ni alloy electroplating was studied by in situ ECSTM. The in situ ECSTMobservation showed a 3-D growth of the Zn Ni alloy crystal in the absence of the additives. However, when additive AA-1/DIEwas introduced to the plating solution, the Zn-Ni alloy crystal grew along the step and layer by layer. This result indicated that the crystal plane of lower electrochemical activity may be reserved to form the highly oriented layer along the surface of the electrode. The X-ray diffraction patterns showed a highly oriented (100) crystal plane of the deposition along the electrode surface in the presence of AA-1/DIEadditive.
    Theoretical Studies on the Structures and Reactions of Halocarbenoids(Ⅱ) ——Structures and Stability of Carbenoid CHClFLi
    LI Ji-Hai, FENG Sheng-Yu
    1998, 19(4):  613-616. 
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    The structures and stabilities of the CHClFLi, as a model carbenoid substituted by two different halogenes, were first predicted by using ab initio theory. Four equilibrium geometries were optimized. Two σ-complexes(geometries 1 and 2), formed by interaction of HOMO of singlet carbene HFC∶ with Li of LiCl, is close in energy and the most stable one. The three-membered ring geometry(geometry 3), formed by interaction of HOMOand LU-MO of singlet carbene HClC∶ with Li and Fof LiF respectively, is “loose” in the structure and more unstable. Geometry 4 is a double three membered ring, and it is the most unstable one. The center carbon of those four geometries except 3 have positive charges, so the nuclophilic reaction of CHClFLi should be slower than that of CHCl2 Li and CHBr 2Li. The transition states of geometries 2, 3 and 4 to 1 were given. The barriers of conversion are very little (1.76, 7.24, 1.53 kJ/mol). The four geometries are all more stable than their corresponding carbene(dissociation energies is 89.67, 87.11, 145.2, 50.11 kJ/mol respectively).
    Ab Initio Study on the Geometries and Reaction Activities of HPXF(X=Li, Na)
    LU Xiu-Hui, WANG Yi-Xuan, DENG Cong-Hao
    1998, 19(4):  617-621. 
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    The Geometries of the two lacking electron fragments HPXF(X=Li, Na) have been investigated by using ab initio method at RHF/6-31G* level, and characteristics of all the geometries have also been analysed in terms of bonding concepts. By comparing with free phosphinidene ( 1HP), reaction activities of HPXF(X=Li, Na) were discussed. Moreover, the effect of alkali metal atoms on the geometries and activities of HPXF(X=Li, Na) have been briefly discussed.The results indicate that both HPLiF and HPNaFhave three types of equilibrium geometries among them, the three-membered ring geometry is the most stable one, and it may be the basic geometry taking part in chemical reactions. It is expected that HPXF(X=Li, Na) is a superior electrophilic intermediate to free phosphinidene in selectivity and control ability.
    Studies on the Structure and Stability of Small Alkali metal Clusters by Using Hückel-Hubbard Method
    HE Fu-Cheng, LI Ji-Shu, LI Xiang-Yuan
    1998, 19(4):  622-625. 
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    The topology and fragmentation of small alkali-metal clusters An,An+,An-(A=Li, Na, K; n ≤5) have been investigated based on the Hückel Hubbard approximation. The calculated results show that the clusters( n ≤5) prefer planar equilibrium geometries. The predominant fragmentation channels associated with the lowest energy difference have been found to correspond to the ejection of either a neutral monomer or a neutral dimer.The odd even alternation is very pronounced for the cluster stability. These qualitative conclusions are in agreement with the experimental ones and the results calculated with more sophisticated methods.
    Partial Oxidation of Methane to Synthesize Gas over Ni/ α-Al2O3 Catalyst Promoted by Noble Metals
    YAN Qian-Gu, YU Zuo-Long, YUAN Song-Yue
    1998, 19(4):  626-628. 
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    The production of synthesis gas by partial oxidation of methane in oxygen has been examined over Ni/ α-Al2O3 catalyst promoted by noble metals(Rh, Ru, Pt and Pd), especially with Pt. The reactivity is considered in conjunction with the result of H2 TPR, CO TPD, SEMand XRD. It is found that small amount of Pt results in a great improvement of activity for the Ni/ α-Al2O3 catalyst. The activity order is : Rh-Ni>Pt-Ni≈Ru-Ni>Pd-Ni, meantime the Pt improves the stability of Ni/ α-Al2O3 catalyst except for Pd which is easy to be deactivated by carbon deposition. The results of TPD, SEMand XRDindicate that there is an interaction between Ni and Pt metals in the catalyst. The interaction increases the dispersions of Pt and Ni, the presence of Pt suppresses the growth and the migration of Ni grains over the surface of the catalyst.
    Synthesis, Crystal and Molecular Structure of Complex [Cu2(Gly GlyO)2(4,4′ bpy)(OH)2]·10H2O
    GUO Xiu-Ying, ZHANG Wen-Xiang, CUI Ai-Li, SHEN Lian-Chun, WANG Feng-Shan, LI Zhi-Ying
    1998, 19(4):  629-632. 
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    A novel binuclear cupric complex with Gly-GlyO chelate ring and 4,4′-dipyridyl as an intermediate radical was synthesized by the reaction of 4,4′-dipy-ridyl and cupric nitrate in aqueous solution. The structural formula of the complex was confirmed as [(H2NCH2CONHCH2COO)(C10 H8N2)Cu(OH)(H2NCH2CONHCH2COO)]·10H2O by X-ray single crystal structure analysis. Crystallographic data are as follows: a triclinic system with a space group P1, a =0.7124(2) nm, b =1.1405(1) nm, c =1.1434(1) nm, α=67.65°, β=79.02°, γ=77.97°, V =0.834(3) nm3, Z =1. The structural data were refined by the block matrix least squares program to final Rvalue of 00727.
    Synthesis and Properties of Two Kinds of Poly( p-phenylene vinylene co-2,5-didodecyl-p-phenylene vinylene)
    GAO Guang-Hua, GUO Jun-Shi, XIE Hong-Quan 
    1998, 19(4):  633-637. 
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    Random copolymers of P(PV-DDOPV) were synthesized via chlorine precursor route, whereas alternating copolymer of P(PV-DDOPV) was obtained through Heck reaction. The two kinds of copolymers were characterized by elemental analysis, GPC, DSCand absorption spectra. The effect of charging ratio on conductivity, solubility and fluorescent properties was studied. Difference of properties between the random copolymer and alternating copolymer was compared.
    Extrusion of High Hoop Strength HDPE Tube by Self-reinforcement and the Study of the Structure and Properties of the Sample
    JIANG Long, SHEN Kai-Zhi, JI Ji-Liang
    1998, 19(4):  638-641. 
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    This article introduced a new extrusion method to produce HDPE pipes with greatly increased hoop strength. The schematic structure and theory of this extrusion system were discussed. Appropriate melt pressure and temperature fields, in conjunction with rotating mandrel permit the production of PEpipes with high hoop strength and modulus. The morphology of reinforced products has been studied by WAXD, SEM and DSC. The reinforcement is due to the shish-kebab structure, which is responsible for the improvement of thermal and mechanical properties. The influence of processing parameter such as melt pressure and speed of mandrel on the strength and modulus of hoop and axis directions has also been investigated. The hoop strength increased with increasing melt pressure and rotating speed of mandrel.
    Complexation Competition in Cationic Polymerization with TiCl4 Coinitiator
    GUO Wen-Li, LI Shu-Xin, MA Yu-Hong, XU Rui-Qing, WU Guan-Ying
    1998, 19(4):  642-646. 
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    The tert-butyl acetate/TiCl4/IB/CH2Cl2, Cl2/TiCl4/IBVE/C6H5CH3, n butyl propenylate/TiCl4/IB/ CH2Cl2 cationic polymerization systems were studied. Summarizing and comparing results of the GPCtraces and the characteristic absorption bands of UVand FTIRspectra respectively, one can conclude: (1) The GPCtraces of polymer changed in line with increase of initiator concentration from unimodal with comparatively high Mw to bimodal showing both high and low Mw fraction. The former unimodal traces are corresponded to single active center[TiCl4←H2O] and the later bimodal traces are corresponded to two active centers comprising both [TiCl4←initiator] and [TiCl4←H2O]. (2) The different properties of polymers obtained by different sequences of chemicals addition and ageing procedure were due to complexation competition and equilibrium which usually required a certain period of time. (3) There are at least two sorts of initiating species in equilibrum.
    Pervaporation Properties of Cross-linked PVA/PVP Blend Membrane(Ⅰ)
    HU Xiao-Hua, PING Zheng-Hua, ZHU Qing, DING Zhi-Ming, DING Ya-Di
    1998, 19(4):  647-651. 
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    The pervaporation properties of the ploy(vinyl alcohol)(PVA) and poly(vinyl pyrrolidone)(PVP) blend membranes crosslinked by glutaraldehyde and a water soluble diazo compound(4,4′-diazidostilbene-2,2′-disulfonic acid disodium salt(DAS) in the separation of ethanol/water mixture were studied. It was found that the pervaporation properties of the membranes are changed as the PVPcontent changed, and the selectivity of the membranes are improved after crosslinking.
    Characterization of Cyclic(aryl ether ketone)s by Matrix-assisted Laser Desorption Ionization-time of Flight Mass Spectrometry
    JIANG Hong-Yan, CHEN Tian-Lu, QI Ying-Hua, XU Ji-Ping
    1998, 19(4):  652-655. 
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    Matrix-assisted laser desorption ionization-time of flight mass spectrometry(MALDI-TOF MS) was used to identify cyclic(aryl ether ketone) oligomers, using 2,5-dihydroxybenzoic acid as a matrix, and Na+ and K+ as cationization agents. The existence of different ring-sized cyclic oligomers up to 9 and their distribution were determined and compared with GPCresults. The results indicated that MALDI-TOF MSwas a powerful and rapid analytical tool for the cyclic oligomers.
    Structural Relaxation of an Inorganic Glass Li2O·2SiO2(Ⅰ) ——Tool Narayanaswamy Moynihan(TNM) Model
    HAN Yan-Chun, YANG Yu-Ming, LI Bin-Yao, Alberto D'Amore, Luigi Nicolais
    1998, 19(4):  656-660. 
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    The main characteristics of structural relaxation and the associated Tool Narayanaswamy-Moynihan(TNM) model are thoroughly introduced. The structural relaxation of an inorganic glass (Li2O·2SiO2) at different aging temperatures and aging times is found to be well modeled by the TNM model.
    The Synthesis and Characterization of Epoxy-terminated Phenolphthalein Poly(cyanoarylether)
    LIAO Wei-Lin, ZENG Xiao-Jun, CUI Guo-Di, WANG Sheng
    1998, 19(4):  661-663. 
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    Epoxy-terminated poly(cyanoarylether)(E-PCE) with Mn from 1000 to 12000 were synthesized by the reaction of epichlorohydrin with PCEoligomer with —OK terminal groups prepared by condensation of phenolphthalein (PPH) with 2,6-dichlorobenzonitrile (DCBN) using K2CO3 as catalyst. The E-PCEs were characterized by IR and 1H NMR spectra, the solubility of E-PCE samples was also measured. In addition, the solidification action and the heat resisting quality of the fully crosslinked E-PCE/DDS were also measured by DSCand TGA.
    Several New Phenomena in the Formation of Ring banded Spherulites of Poly( ε-caprolactone) and Poly(styrene-random-acrylonitrile) Blends
    WANG Zhi-Gang, LUO Jun, JIN Jiao-Kai, JIANG Bing-Zheng
    1998, 19(4):  664-666. 
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    Ring-banded spherulites in crystallization of poly( ε-caprolactone) and poly(styrene-random-acrylonitrile) blends were observed with polarizing optical microscopy and digital image analysis technique was applied directly to the image obtained by polarizing microscope. Several new interesting phenomena were found. One is that the ring-banded structure is still clearly seen after the analyzer was removed and this astonished phenomenon couldn't result from the general concept about formation mechanism of ring-banded spherulite——lamellae twisting. Another one is that there is a slight, dark line in the bright band when cross polars were added, which may be related to the formation process and mechanism of ring-banded spherulites in the blends of poly( ε-caprolactone) and poly(styrene-random-acrylonitrile).