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Table of Content

    24 March 1998, Volume 19 Issue 3
    Articles
    Studies on the Magnetic Properties of Binuclear Copper(Ⅱ) Complex of a Bibracchial Lariat Ether
    ZHANG Hua, WANG Guo-xiong, JI Feng, WANG Gu-Feng, WANG De-Fen, HU Hong-Wen, YAO Tian-Yang
    1998, 19(3):  331-334. 
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    The variable temperature(4~300 K) magnetic susceptibility of binuclear copper(Ⅱ) complex of the bibracchial lariat ether [Cu2L(OH) (ClO4)3Me2CO(L= N,N'-bis(8-quinolylmethyl)-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane) (1) was measured in an appropriate magnetic field of 500000 A/m. The strongly antiferromagnetic interaction constants are as follows: J =-257.7 cm-1, Zj'=-30.1 cm-1. It is shown that there is an antiferromagnetic interaction between molecules. The | J | value (<500 cm-1 ) is not large enough to lead to the diamagnetic coupling. The plot of χm-H, which is different from the normal plot of χm-H, is explained through the spin canting phenomenon. By analyzing the crystal structure of the complex and 3d orbitals of two Cu2+ cations, we suggest that the exchange path is through OH bridge. Compared with the other two analogous binuclear copper(Ⅱ) complexes coordinated by macrocycle ligand and bridged by OH, we analyzed the correlation between J value and the overlap of orbitals.
    Studies on Divalent Thulium Ternary Iodide
    WANG Shi-Hua, WANG Mei-Tian
    1998, 19(3):  335-339. 
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    In this paper two types of compounds [ATmI3(A=K, Rb, Cs) and A4TmI6(A=Rb, Cs)] were synthesized by one-step procedure and their crystal structures were determined by X-ray powder diffraction. The crystal structures of CsTmI3, RbTmI3 and KTmI3 are orthorhombic ones. CsTmI3: a =0.8689(3) nm, b =1.2339(4) nm, c =0.8565(3) nm, space group: Pnma, Z =4; RbTmI3: a =1.0381(3) nm, b =0.4686(3) nm, c =1.7256(9) nm; space group: Pnma, Z=4; KTmI3: a =0.4576(2) nm, b =1.5133(20) nm, c = 1.1679(6) nm, space group: Cmcm, Z =4; The linking manner among the structural unit [TmI6] of octahedral in the three kinds of structures are different and they are corner-sharing, edge-sharing and both corner-and edge-sharing separately. The coordination number of atom of Cs, Rb and K decreases orderly and they are 10, 9 and 8. The structures of Cs4TmI6 and Rb4TmI6 belong to K4CdCl6-type(trigonal, space group: R3 c, Z =6). Rb4TmI6: a = 1.41714(9) nm, c =1.7473(1) nm, Cs4TmI6: a =1.4516(1) nm, c =1.8292(2) nm.
    Mild Hydrothermal Syntheses and Characterization of Nanocrystalline Titanlanthanates
    MAO Ya-Chun, FENG Shou-Hua
    1998, 19(3):  340-344. 
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    Novel perovskite titanlanthanates, M0.5La0.5TiO3 (M=Na, Ag0.66Na0.33, Li0.6Na0.4) were hydrothermally synthesized under mild conditions, and characterized by means of X-ray diffraction(XRD), scanning electron microscopy(SEM), differential thermal and thermogravometric analyses(DTA-TG), inductively coupled plasma analysis(ICP) and infrared spectroscopy(IR). The ionic transport properties were measured by an ac impedance method. Some factors, e.g., crystallization temperature, pH, and Ti/La molar ratio in reaction mixture dominate the hydrothermal syntheses of the single phase products. Na0.5La0.5TiO3 and Ag0.33Na0.17La0.5TiO3 crystallized in cubic system with cell parameters: a =0.3877 nm and a =0.3890 nm, respectively, whereas Li0.3Na0.2La0.5TiO3 has orthorhombic symmetry with parameters a =0.3894 nm, b =0.3912 nm and c =0.3890 nm. Under a similar experimental condition, the average particle sizes of the products are 50 nm for Na0.5La0.5TiO3, 70 nm for Ag0.33 Na0.17La0.5TiO3 and 5 Lm for Li0.3Na0.2La0.5TiO3. An ac impedance study indicates that conductivities of Ag0.33 Na 0.17La0.5TiO3 and Li0.3Na0.2La0.5TiO3 at 713 Kare 1×10-5 and 1×10-6 S/cm, respectively.
    Studies on the Thermal Dissociative Process of Microcline
    QIU Long-Hui, WANG Li-Sheng, JIN Zuo-Mei
    1998, 19(3):  345-349. 
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    The microcline CaSO4-CaO system was determined to be used to obtain K2SO4 by thermodynamical analysing and computing lots of possible reactions of 6 microcline systems. The effects of roasting temperature, time and ratios of reactants on the potassium recovery of the microcline CaSO4-CaCO3 were studied and the favorable conditions were determined as follow: 1323 K, 3.0 h, m (microcline)∶ m (CaSO4·2H2O)∶ m (CaCO3)=1∶1∶3. In the presence of 0.9% additive I, the roasting temperature decreased from 1323 Kto 1223 Kand the potassium recovery was 84%. Kinetic experimental data of the two systems with or without additive I both fitted a diffusion-through-product-layer-reaction-controlmodel, and their kinetic equations were presented with apparent activation energies 184.4 kJ·mol-1 and 158.9 kJ·mol-1 respectively.
    Production of Various Forms of Nanotubes by AC Arc Discharge
    ZHU Ling, ZENG Huang, HAO Guang-Ming, SHENG Rong-Sheng
    1998, 19(3):  350-352. 
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    V arious forms of nanotubes were produced by AC arc discharge method at a low He pressure. Because the two graphite electrodes we used have the same diameter, there was no deposit formed on the end of the cathode. This is a significant difference from the conventional DC method used to form carbon nanotubes. Some forms of nanotubes different from those reported were found in the soot(but not the cathode deposit). They were the carbon nanocapsule, carbon cone-shaped nanotube and the carbon toroidal nanotube. The nanocapsule has a length-diameter ratio below the conventional nanotubes. The cone nanotube has a cone shape. The toroidal nanotube has a shape like a tire. These novel products were found in the soot. Their formation may arise from the periodic alternantion of the current we used. The difference of the formation mechanisms between AC arc discharge and DC arc discharge were discussed.
    On-line Capillary Electrophoresis-mass Spectrometry for Determination of Peptide Mixture and Protein Mixture
    ZHOU Guo-Hua, LUO Guo-An, ZHOU Ke-Yu, GU Zhuo-Liang
    1998, 19(3):  353-358. 
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    The influence of uncoated, coated linear polyacrylamide(LPA) and amino coated capillaries on the separation of five peptide mixtures, including angiotensin Ⅰ, Ⅱ, Ⅲ, substance P and somatostain, was studied. The results showed that the peptide mixtures could not be separated completely in uncoated capillary by volatile buffer which was suitable for the MSanalysis, whereas they could be separated in LPA and amino coated capillary by pH 5.0 and pH 4.5 NH4Ac buffer respectively. In addition, the above peptide mixtures, protein mixtures comprised of myoglobin and carbonic anhydrase Ⅱ, tryptic digests of erythropoietin, were separated and characterized by capillary electrophoresis mass spectrometry(CE-ESI-MS) with electrospray ionization interface. The factors affecting the determination in CE-ESI-MS were also discussed.
    Simultaneous Determination of Mixed Metal Ions by Complexometric Titration and Principal Component Regression
    NI Yong-Nian, WU Ying-Liang, JIN Ling
    1998, 19(3):  359-362. 
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    Anew method of complexometric titration for determination of mixed metal ions with principal component regression(PCR) was developed. The principle of this method was described and the linear complexometric titration equation was derived. In this work, a mercury film electrode(MFE) was used as the indicator electrode for potentiometric measurements, and a double junction Ag/AgCl electrode as the reference electrode. The mixtures of metal ions were titrated with ethylenediamine teraacetic acid(EDTA), the potentiometric titration data were recorded at each selected potential points and were then treated by chemometric approach of PCR. A set of synthetic mixtures of lead, copper, zinc and cobalt with concentration levels from 0.5 mmol/Lto 1.5 mmol/Lwere analyzed by the proposed method and acceptable results were obtained.
    Studies of the Piezoelectric Immunosensor for the Detection of Fibrin Using Protein A Oriented Immobilization of Antibody
    PEI Ren-Jun, HU Ji-Ming, HU Yi, ZENG Yun'E
    1998, 19(3):  363-367. 
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    Ahighly sensitive piezoelectric crystal immunosensor has been developed for the detection of human fibrin. The crystal used was 9 MHz quartz AT-cut with gold coated electrodes. Three methods for immobilization of anti-fibrin antibody on the gold electrodes were employed. The immobilization method with a thin protein A layer gave the best results in terms of sensitivity, stability and reproducibility. The crystal was precoated with either polyethyleneimine adhesion and glutaraldehyde cross-linking, or bovine serum albumin adsorption and glutaraldehyde cross linking, gave inferior results. Protein A molecular membrane could be developed as a matrix for oriented immobilization of antibody molecule because of both specific binding to the Fc fragment of IgG and adsorption strongly to the gold electrode surface. In this paper, quartz crystal was dipped into 0.1 g/L protein A solution. Then a thin protein A membrane was performed on the crystal surface so that fibrin antibody could be effectively self-assembled. Then an orderly and closely arranged self-assembled antibody molecular membrane was immobilized orientationally on the protein A layer. The coated crystal using this immobilization method was stable for 6 weeks when stored in silica gel dry over at room temperature. The influence factors related to the sensitivity of the system such as the concentration of protein A coated, the titer of antibody, the absorption time of protein A, the immobilization time of antibody, the reaction time of immunoreaction etc., were discussed. U nder the optimized experimental conditions chosen, the coated crystal had a good response to fibrin in the concentration range of 1×10-4~1×10-2 g/L. This sensor had a good selectivity, other materials in human serum did not interfere the detection. The reusability of the immunosensor was also studied. We eluted the bound materials on the crystal surface with strong acid and alkali solutions, then the crystal was washed with ultrasonic bath. The crystal could be regenerated nearly 10 times without detectable loss of activity.
    Investigation of 3.5th Order Differential Cyclic Oscillochronopotentiometry
    ZHENG Jian-Bin, FU Ye-Wei, LI Yuan, GAO Hong
    1998, 19(3):  368-371. 
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    The semiintegral and semidifferential technology was applied to process cyclic oscillochronopotentiometric signal in this paper.The instrument of 3.5th order differential cyclic oscillographic chronopotentiometry has been designed. The experimental results of determination for Cd, In, Rh and Pb in pH=10 HAc-NaAc-0.06% HCup solution show that the method has three advantages: (a) compared with the classifical oscillographic method based on dE/dt~E curve, the sensibility of the new method is increased about 5~10 times; (b) better resolving power; (c) the peak height caused by depolarizer on Y3.5~E curve is easy to be measured. As a result, 35th order differential cyclic oscillographic chronopotentiometry will become a really feasible analytical method.
    Recent Development of Intermediate Ion/Neutral Complexes
    SHE Yi-Min, LIU Zhi-Qiang, LIU Shu-Ying
    1998, 19(3):  372-378. 
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    The fundamental aspects of ion/neutral complex as an important intermediate of unimolecular fragmentation in mass spectrometry have been summarized in this review, especially for the classified description of its formations, characteristics, reactions, investigation methods, recent achievements and application. Meanwhile, another kind of proton-bound complex, which is a special type of ion/neutral complex, has been also introduced briefly. Among them, a part of authors' work was included.
    Studies on Ray-tracing of UV Detector in High Performance Capillary Electrophoresis
    XU Xu, WU Ru-Jin, LIN Bing-Cheng
    1998, 19(3):  379-381. 
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    A computer program is compiled to work out the ray tracing of UV detector of high performance capillary Electrophoresis (HPCE). Based on calculating results obtained by calculating, some practical methods for adjusting the distance between lens and capillary are provided to make UV detector work on the optimatic condition. The experiments with the aid of the method show a satisfactory detection sensitivity. The method for adjusting ray tracing can be used into all kinds of HPCE UV detector.
    Fabrication of a Self-assembling Film Electrode Containing Vanadium-oxygen Phthalocyanine and Its Electrocatalytic Oxidation for Hydrazine
    SUN Chang-Qing, LIU Guo-Jing, ZHANG Hong-An
    1998, 19(3):  382-384. 
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    A monolayer containing vanadium-oxygen phthalocyanine on the surface of 2 dimethylaminoethanethiol-modified gold electrode was achieved based on electrostatic interaction. The electrode exhibits a high catalytic activity toward the electrooxidation of hydrazine. The method is very useful in other fabrication of functional molecules.
    The Studies of Synthesis and Spectral Characterization of Bis[N,N'-ethylene-2,2'-(phenylmethylene) bis(3,4-dimethylpyrrole-5-aldimino)]dimanganese and Biomimetic Catalytic Reaction
    CHEN Xin-Bin, ZHU Shen-Jie, GUI Ming-De
    1998, 19(3):  385-390. 
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    This paper first reports the synthesis and spectral characterization of bis [N,N'-ethylene 2,2'-(phenylmethylene)bis(3,4-dimethylpyrrole-5-aldimino)] dimanganese as well as the biomimetic catalytic properties for the monooxygenation of cyclohexane with PhIO. The results show that the catalytic properties and stability of this binuclear manganese complex are similar to those of TPPMnCl and better than those of other Schiff base complexes known.
    Studies on the Separation and Extraction of α-Amylase and Proteinase from Fermented Liquor of α-Amylase by Aqueous Two-phase Partitioning
    JIAO Qing-Cai, LIU Qian, CHEN Yao-Zu
    1998, 19(3):  391-394. 
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    Aqueous two-phase system composed of PEG/(NH4)2SO4 was once to isolate α-amylase and proteinase from fermented liquor of α-amylase in this paper. The optimum extraction conditions were: 15% PEG1000, 20% (NH4)2SO4, pH=8, the partition coefficient of α-amylase was as high as 19.6 with a yield of 90%. The separation coefficients between α-amylase and proteinase were 15.1 and 1.5 folds increase of specific activity compared with those the original fermented liquor. The yield of proteinase in water phase was more than 60%. The preliminary study on back-extraction condition was done in this paper.
    Syntheses and Antitumor Activities of Spin-labeled5-Fluorouracil Derivatives
    MAO Man-Jun, TIAN Xuan, CHEN Yao-Zu
    1998, 19(3):  395-398. 
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    Ten new spin-labeled derivatives of 5-fluorouracil(2a-8) were synthesized by introducing four kinds of stable nitroxyl radicals into N1 and N3 site of 5-Fu. The structures of these new compounds were confirmed by IR, UV, MS, ESR spectra and elemental analysis. The antitumor activities of these compounds were tested to be against KB, HCT-8 and A 2780. The preliminary results showed that the antitumor activities of compounds 2a and 3a were stronger than that of 5-Fu and were similar to that of HCFU.
    Studies on the Asymmetric Synthesis of(R)-α-Terpineol
    PEI Wen
    1998, 19(3):  399-401. 
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    (R)-α-Terpineol, a natural product, was synthesized enantioselectively by an asymmetric catalyzed Diels-Alder reaction from 1-phenylsulfonyl-3-buten-2-one with 2-methyl-1,3-butadiene. The optical purity of (R)-α-terpineol was obtained in 92% ee.
    Asymmetric Diels-Alder Reactions of α'-Benzenesulfonyl-α,β-Unsaturated Ketones with Cyclopentadiene Catalyzed by a Chiral Titanium Reagent
    PEI Wen
    1998, 19(3):  402-405. 
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    Asymmetric Diels-Alder reaction of α'-benzenesulfonyl-α,β-unsaturated ketones with cyclopentadiene using a catalytic amount of a chiral titanium reagent was performed. The Diels-Alder adducts were achieved in high yields and high enantioselectivities. The relationship between the substituent on the dienophile and reactivity and also the optical purity of the product were discussed. The absolute configuration of the cycloadducts was determined by an alternative synthetic route of compound 2 also by an asymmetric Diels-Alder reaction of the acyloxazolidinone 4 with cyclopentadiene, and the nucleophilic addition of benzenesulfonylmethyl lithium to the product.
    Rhabdasterol——A Novel Steroid from the South China Sea Marine Sponge Rhabdastrella sp.
    RAO Zhi-Gang, DENG Song-Zhi, WU Hou-Ming, JIANG Shao-Kai
    1998, 19(3):  406-407. 
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    Rhabdastero——25(29)-methylene-26-methyl-26-ethycholesterol, a novel marine sterol with unusual side chain has been isolated from a yellow sponge Rhabdastrella sp., which was collected from South China Sea. The chemical structure has been determined by spectral data of IR, HRMS, EIMS, 1H NMR, 13C NMR and TOCSY etc..
    The Reactions Between 3-Aroylethylsydnones and Phenylhydrazine
    ZHANG Zhan-Bin, WU Yong-Ren, YIN Cheng-Lie
    1998, 19(3):  408-409. 
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    3-Aroylethylsydnones and phenylhydrazine were heated in ethanol via an elimination, condensation, and cyclization to give 1-phenyl-3-arylpyrazolines. Their structures are confirmed by elemental analysis, IR, UV and 1H NMR analysis.
    Synthesis and Crystal Structure of Aluminium Complex with 3-Hydroxyflavone
    WU Yi-Qun, ZHANG-Bin, ZHU Qing-Tao, WU Zhen, LIN Yong-Hua, XING Yan, HUA Rong
    1998, 19(3):  410-413. 
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    Al[(C15H9O3)3]2·2CHCl3·8H2O was synthesized, and its crystal structure was determined. It belongs to trigonal system, R3, a=b =1.6558(3) nm, c =3.6465(20) nm, α=β=90°, γ=120°, V =8.65608(0.00586) nm3. Dc=1.45 g/cm3, μ(Mo Kα)=3.20 cm-1, F (000)=3924. The crystal structure was solved by Patterson and Fourier techniques, and refined by a block-diagonal least-squares method. A total of 3737 independent intensity data were collected, of which 1033 with I ≥3σ( I0) were observed, R=0.0918, Rw= 0.0918. Al3+ ion was 6-coordinated, bound to six oxygen atoms from three 3-hydroxyflavones to form a distortional coordination octahedron.
    Studies on the Elimination of NO over the La-Ba-CU Mixed Oxide Catalysts with Perovskite Structure
    LIU Yu, YANG Xiang-Guang, ZHAO Zhen, WU Yue
    1998, 19(3):  414-418. 
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    The mixed oxides, including YBa2Cu3O7, LaBa2Cu3O7, LaBaCu2O5, La2BaCu3O7, La4BaCu5O12 with perovskite structure, were prepared. The catalysts were characterized by means of chemical analysis, XRD, TPD and TPR method. It was found that they were the active catalysts for the NO decomposition and NO reduction by CO. The existance of Cu3+ is an important factor to give the catalysts a high activity for the NOreduction by CO.
    Studies on Cellulose-based Magnetic Polyamidoxime Adsorbents——Copper Chloride Adsorbed by Alkali-treated Resin
    YANG Chao-Xiong, WU Jin-Yuan
    1998, 19(3):  419-423. 
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    Cu2+ ions can be adsorbed by alkaline cellulose-based magnetic polyamidoxime adsorbent(BMAO). After contact for 20 min, the adsorption capacity and the binding ratio were found to be 0.69 and 0.59, respectively, and then the adsorption rate decreases suddenly. It is considered that the reaction is going into the next stage. The results of adsorption kinetics and the observation of SEM suggested that CuCl2 was adsorbed by BMAO to give a bidentate chelate, and the redox reaction took place between them afterwards. The results obtained by the variation of CuCl2 concentration or liquid-solid proportion show that BMAO is suitable for CuCl2 uptake from dilute solution and adsorption on a large-scale.
    Ab Initio Studies of Lithium Ethenolate
    WANG Yi-Gui, SUN Chang-Jun, DENG Cong-Hao
    1998, 19(3):  424-428. 
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    Two possible geometries of CH2=CH-OLi and transition states between them were optimized by using RHF/3-21G and RHF/6=31G*. The stability of the two structures were discussed. The mechanism of producing CH2=CH—OLi from CH3—CH(=O) and Li-OH in gas phase was investigated under RHF/3-21G level. We found that the concerted mechanism was preferred. We also calculated the reaction heat by using 6-31G* basis sets at MP 2 level.
    Studies on the Energy Band Structures and Chemical Bond Properties of LaX(X=N,P,As,Sb)Crystals
    MENG Qing-Bo, WU Zhi-Jian, ZHANG Si-Yuan
    1998, 19(3):  429-432. 
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    The energy band structures of LaX(X=N, P, As, Sb) crystals have been studied by using LMTO-ASA method. The calculated energy gaps of these crystals are 2.30 eV for LaN, 2.05 eV for LaP, 16.6 eV for LaAs and 1.34 eV for LaSb. The results are in good agreement with experimental data. At the same time, using these calculated results of energy band structures of these crystals, the chemical bond properties have been analyzed and calculated. The covalency values of these crystals are 26.15% for LaN, 32.54% for LaP, 33.30% for LaAs and 36.49% for LaSb, which agree satisfactorily with the calculated ones by using PV(Phillips-Vechten) theory.
    Kinetics of Catalysis by Ribonuclease A in Reverse Micelles Formed by Dodecylammonium Butyrate and Water in Cyclohexane
    GUO Hong, HUANG Wen, GU Ti-Ren
    1998, 19(3):  433-437. 
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    The kinetics of hydrolysis of cytidine 2',3'-cyclic phosphate(CP) catalyzed by ribonuclease A(RNase A) solubilized in reverse micelles formed by dodecylammonium butyrate(DAB) in cyclohexane has been investigated. The results show that the Michaelis-Menten law can be applied to DAB-cyclohexane reverse micellar solutions as well as to aqueous solutions. The enzyme efficiency(expressed in terms of the ratio kcat/km) of RN ase A solubilized in DAB cyclohexane reverse micellar solutions is 14—30 times of that in aqueous solution. Under the conditions at constant concentration of DAB as well as at constant molecular ratio of H2O and DAB, the enzymetic activity of RN ase A in reverse micellar solutions decreases as the water content is increased. The results were explained briefly in terms of the changes in the conformation of the enzyme as well as in the concentrations of the enzyme and the substrate in inner water phase.
    Comparative Studies of Methanol and Methathiol Decomposition Reactivity on Metal Surfaces
    XIA Wen-Sheng, WANG Hai-You, WAN Hui-Lin, ZHANG Qian-Er
    1998, 19(3):  438-441. 
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    The reactivities of methanol and methathiol on Ni(111), Pt(111) and Cu(111) have been investigated using bond order conservation-Morse potential(BOC-MP) method. The results show that, from Ni to Pt to Cu, the relative cleavage probabilities of C-S bond in methathiol decrease, and those of S-H bond increase, and thus on Cu surface only the S-H bond break occurs. Methanol on Ni surface is dissociated easily into CH3- and CH3O-, but the dissociation on Pt and Cu surface is not easy. From Ni to Pt to Cu, the cleavage selectivity of C-S bond in CH3S— and C-H bond in CH3O— increases. The dissociation barriers of CH3XH and CH3X—(X=O, S) increase in the order Ni<Pt<Cu. The final product of CH3OH dissociation is CO on Ni surface, and H2CO on Cu surface.
    Hydrogen Transfer Hydrogenation of Acetophenone by Ruthenium Complexes Containing Polydentate Aminophosphine Ligand
    XU Pian- Pian, GAO Jing-Xing, ZHENG Rong-Hui, PENG Wei-Ping, HUANG Pei-Qiang, WAN Hui-Lin, WANG Wen-Guo, DING Kai-Ning, CHEN Shou-Zheng
    1998, 19(3):  442-445. 
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    The catalytic hydrogen transfer hydrogenation of acetophenone using C2-symmetric diamine/diphosphine ruthenium(Ⅱ) complex has been studied. Complex RuCl2(P2N2H4) shows an excellent catalytic activity in hydrogen transfer hydrogenation of acetophenone in a molar ratio of substrate/Ru/iso-PrOK 200∶1∶12, leading to 2-phenylethanol in 99% yield after 2 h. Ahydrogen transfer mechanism is also discussed.
    Theoretical Study on Structure,Electronic Spectra and13C NMR spectra of C60O3
    TIAN Wei-Quan, FENG Ji-Kang, GE Mao-Fa, REN Ai-Min, LI Zhi-Ru, HUANG Xu-Ri, SUN Chia-Chung
    1998, 19(3):  446-450. 
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    Various possible isomers of C60O3 were studied by using INDO methods. The calculation results suggest that the addition take place readily on the 6-6 bonds near to the epoxide structure. Among the possible isomers, the isomer in which all the three epoxides of 6-6 bond are on one six-membered ring is the most stable one. The other two isomers C2, Cs with the third oxygen being added on the adjacent six membered ring's 6-6 bond are also stable. The calculated 13C NMR spectra of C2 and Cs are consistent well with those of experiment. The calculated electronic spectra of C60O3 is of prediction. Maybe, C60O3 has a good reactivity.
    Effect of Alkyl Group on the Structures and Thermal Stability of Substituted Lithofluro-Silylenoids R2SiLiF
    FENG Da-Cheng, FENG Sheng-Yu, DENG Cong-Hao
    1998, 19(3):  451-454. 
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    Isomeric structures and energies of dimethyllithoflurosilylenoid and diethyl lithoflurosilylenoid were investigated by using ab initio molecular orbital theory. Alkyl groups increase the donor of σ electrons of silicon to lithium atom and it leads to an increase of the thermal stability of σ-complex. But alkyl groups decrease the donor of π electrons of fluorine atom to silicon, leading to a decrease of the thermal stability of p-complex. However, because of the joint action of that two effect, alkyl groups change little the thermal stability of the three-membered ring.
    Collapsed Deposition of Accelerated C60 Beam on Solid Surfaces(Ⅲ)——ab initio Calculation of Quantum Chemistry
    LIN Meng-Hai, LU Yun-Peng, TANG Zi-Chao, ZHENG Lan-Sun
    1998, 19(3):  455-456. 
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    C60 molecule was absorbed on the Au(Ⅲ) surface and studied by ab initio calculations. It may be formed plane shaped molecule C45 or C48, and plane shaped C60 (C5v) or hill shape C60 (C6v), if added more carbon atoms.
    Effect of Surfactants on Stability and Rheological Properties of Highly Concentrated Aqueous Titanium Dioxide Suspensions
    CHEN Xiao-Bin, CHENG Hu-Min, MA Ji-Ming
    1998, 19(3):  457-459. 
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    The effects of sodium dodecyl sulfate(SDS) and ethoxylated octylphenol(TX100) on the adsorption, stability and rheological properties of aqueous TiO2 suspensions have been studied. It was found that the adsorption isotherm of SDS on TiO2 surface was shown to be the type of "S". With the increasing of SDSconcentration, the ζ potential and stability increase, while the viscosity and yield value decrease at first and then increase. The adsorption amount of nonionic surfactant TX100 is much smaller than that of SDS. No obvious effect was shown on the stability and rheological properties of the TiO2 suspensions.
    Volume Phase Transition of Copolymerized Sulfonic Acid Gels in Mixed Organic Solvents
    LIU Xin-Xing, HU Ou, TONG Zhen, GU Ju
    1998, 19(3):  460-463. 
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    Radical copolymerization of 2-acrylamido 2-methylpropane sulfonic acid(AMPS) with 2-hydropropyl methacrylate(HPM) was conducted in ethylene glycol/water(1∶1 in weight) at 70 ℃. The azeotropic composition was found at the monomer molar ratio of AMPS/HPMas 8/2. Three sulfonic gels were prepared at this composition with the crosslinker N,N'-methylene-bis(acrylamide) of 2%, 3% and 5%(molar percentage), and referred to as G02, G03 and G05, respectively. As expected from their polyelectrolyte nature, these gels swell in dimethyl sulfoxide(DMSO) but shrink in tetrahydrofuran(THF) at 25 ℃. The volume phase transition takes place in the G02 and G03 swollen in DMSO/THF mixtures when THFcontent is increased beyond 55%~60%(volume ratio). In ethanol/THF mixture, however, no volume phase transition was found though the gel still shrunk with increasing THF. The dipole dipole interaction model in less-polar medium was adopted to interpret these results with the concept of preferential solvation.
    Real-time Characterization for Surface Wettibility of Cysteamine Self-asembled Monolayers on Gold
    ZHAO Jian-Wei, YU Hua-Zhong, WANG Yong-Qiang, LIU Zhong-Fan
    1998, 19(3):  464-468. 
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    The characteristic change of surface wettibility of cysteamine self-assembled monolayers was reported. Contact angle titration method was used to carry out the real time measurements of the surface wettibility of the monolayers which were formed by dipping gold substrate into dilute HSCH2CH2NH2/CH3CH2OH solution. After the monolayers transfered from solid/liquid interface to solid/air interface, the contact angles of the monolayers underwent a sharp increase, then got down to a slow variation process. From the perspective surface free energy, the structural rearrangement of monolayers was considered as the main reason for such a phenomenon. The contact angle titration curve for basic group tailored SAM swas obtained by using a series of solutions with different pH values. The pKb value of cysteamine SAM swas derived to be 1.7±0.2. Based on above characterization, the change of surface wettibility for the monolayers was further studied at a long time scale by taking account of changes in pKb and △θ (difference between two plateaus of the contact angle titration curve).
    Studies on Nucleation of Cellulose Aromatic Ester Thermotropic Liquid Crystal on Polyethylene Terephthalate
    RUAN Wen-Hong, SHEN Jing-Wei, LI Bai-Qian
    1998, 19(3):  469-471. 
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    Using a self prepared cellulose aromatic ester(CAE) thermotropic liquid crystal as polyethylene terephthalate(PET) nucleating agent, the isothermal crystallizing kinetics characteristics of PET/CAE(CAEcontent≤1%) in the temperature range of 110~200 ℃ were investigated. The results show that CAEcan significantly accelerate crystallizing rate (Z) of PET, with the change of crystallizing temperature and CAE content, Zhas a maximum value Zmax (TC) and Zmax ( WCAE), the temperature Tmax corresponding to Zmax (TC) decreases with the increase of CAE content. The mechanism of CAE accelerating PET crystallization is different from that of common nucleating agent.
    Stability of Emulsion Copolymerization of Acrylic Monomers Containing Amino and Hydroxyl Groups
    YU Zhang-Qing, LI Bo-Geng, LI Bao-Fang, PAN Zu-Ren
    1998, 19(3):  472-476. 
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    The copolymer latex of MMA-BA-HEMA-DMAEMA was prepared in the batch and semi-continuous emulsion copolymerization process. The effects of emulsifier type and concentration, polymerization temperature and the feeding rate of emulsified monomer on the stability of polymerization were studied systematically. The results show that the HLB is not critical parameter for selecting the emulsifier used for the emulsion polymerization containing water-soluble monomers. The available method for determining emulsifier system is still directly by the stability observation of the polymerization runs. The increase of functional monomer HEMA and DMAEMA content is beneficial to polymerization stability. The decrease of the polymerization temperature and the reduction of the feeding rate of the emulsified monomers are favorable to the stability of polymerization. The stability of batch polymerization is inferior to that of semi-continuous polymerization for this system. The results also show that the increase of the emulsifier concentration will improve the stability of polymerization and uniformerize the particle size.
    Development in the Thermodynamic Theories of Polymer-Polymer Miscibility
    TANG Ping, LI Guang-Xian, HUANG Rui
    1998, 19(3):  477-482. 
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    The recent development of thermodynamic theories of polymer blend, including the F-H mean-field theory and the equation of state theory were reviewed in the paper, and the simplification of EOS as well as its application in the study of homopolymer and copolymer blend systems was discussed in detail.
    Synthesis and Characterization of Poly(ester-ether)s as Thermoplastic Liquid Crystalline Elastomers
    YANG Cheng, WU Da-Cheng
    1998, 19(3):  483-485. 
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    In this paper a series of new thermoplastic liquid crystalline elastomers were synthesized by high temperature solution polycondensation of 4,4'-(terephthaloyldioxy) dibenzoyl chloride, 1,10-decandiol, and poly(ethylene glycol) (PEG 1500). Their thermal properties and liquid crystalline behavior were characterized by DSC and polarizing optical microscope. Tensile strength values of these block copolymers were in the range of 10~40 MPa, elastic modulus values 5~30 MPa, and elongation values at break 200%~320%.
    Surface Modification of Polyethylene by Microwave Plasma
    WANG Zhen, QIU Ye, HONG Pin-Jie, DAI Shu-Shan, YANG Ai-Min, CUI Yong-Jie
    1998, 19(3):  486-488. 
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    Surface modifications of polyethylene(PE) by various microwave plasma(N2, CO2, O2) were investigated and compared. These plasma treatment all improve the hydrophilicity of samples and introduce oxygen-containing groups into the samples surface. Moreover amine was also formed for the N2 plasma modified. The effect of N2 plasma modification is best on the improvement of surface hydrophilicity, and its modification depth is about 5~6 nm, which can be got by calculating from the result of angular dependent ESCA analysis. The influences of sample location, microwave power, system pressure and treatment time on hydrophilicity of plasma modified PE were also studied. The results show that a similar pattern and the optimal operation conditions are suited for these plasma treatment.
    Microwave Plasma-initiated Grafting of Methyl Methacrylate onto Polyethylene Surface
    QIU Ye, WANG Zhen, HONG Pin-Jie, DAI Shu-Shan, ZHANG Cheng-Cong
    1998, 19(3):  489-491. 
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    The He cold plasma excited by microwave was used to activate the surface of polyethylene(PE). It resulted in forming of active sites on the surface and was followed by graft reaction with methyl methacrylate(MMA). The MMA-grafted samples were shown to be more hydrophilic than of untreated one. The influence of MMA conentration, microwave power and plasma treatment time on the graft degree and wettability for MMA-grafted PE were also studied. A coincidence of graft degree with wettability of PE films was found. The optimal operation condition was also advice, that is, MMA concentration, microwave power, and plasma treatment time were 0.1 mol/L, 200 W and 2.5 min, respectively.
    Free Radical Copolymerization of Fullerenes(C60/70) with Acrylic Acid
    GUAN Wen-Chao, DUAN Biao, YU Jun
    1998, 19(3):  492-493. 
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    C60/70 acrylic acid water soluble copolymer, whose average molecular weight is 2000, was synthesized by means of typical free radical copolymerization method. C60/70 (85% C60, 14%C70, 1% high fullerenes) mixture of 45 mg and 2.5 mLacrylic acid were dissolved in 15 mL toluene. The polymerization was initiated by 30 mg A IBN at 70 ℃ under the protection of N2 for 13~15 h, yielding a red brown precipitate. The pured copolymer which is soluble in water has significantly different spectroscopic properties from C60/70.
    Studies on Fracture Morphology of Short Carbon Fiber Reinforced Poly(phenylene ether ketone)(SCF/PEK-C)Composites
    ZHAO Dong-Yu, LI Bin-Yao, YU Fu-Sheng
    1998, 19(3):  494-495. 
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    The shear fracture morphology of SCF/PEK-C composite with carbon fibers treated for different times was studied carefully by SEM. The result shows that the adhesion between fiber and matrix was improved and fractured model also changed from interface fracture to brittle fracture with increasing treatment time of carbon fiber.The fracture mechanism was discussed prelimiary.