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    24 February 1991, Volume 12 Issue 2
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    Articles
    The Extraction and Complexes of Silver with 1,2-Bis[alkyl(aryl)thio] ethane
    Shao Pin-xi, Yao Xin-kan, Wang Hong-gen, Wang Wen-hu, Liu Bin, Li Mei, Luo Li-wen, Xu De-he
    1991, 12(2):  143-147. 
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    In this paper the extraction of silver with RSCH2CH2SR(L)[R=n-C3H7(BPrTE),n-C5H11(BATE), n-C8H17(BOTE), C6H5(BPTE)] is studied. The effects of concentration of nitric acid, diluent and Rgroup on the extraction are discussed. It is found that silver can be quantitatively extracted from large amount of common metals and chloride in nitric acid medium. The study on the solution complexes and the analyses of solid and liquid complexes indicate that the composition of complexes is in ratio Ag : L=2. 5=1, 2 : 1, 3 : 2, 1 : 1, 2 : 3 and 1 : 2.
    Studies on Ternary Complexes of Antitumour Compound 7-Oxabicyclo-[2,2,1]-hept-5-ene-2,3-dicarboxylic Acid with Amino Acidsand Computer Simulation of Blood Plasma Model
    Huang Zhong-xian, Wang Yun-hua, Dai Xiao-ying, Chen Jun
    1991, 12(2):  148-152. 
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    The ternaty complex formation constants of 7-oxabicyclo-[2,2, 1]-hept-5-ene-2,3-dicar-boxylic acid (OHDA) with several typical amino acids and Zn(Ⅱ), Cu(Ⅱ) were potentiometrically determined under physiological conditions(37℃, 0. 15 mol/L NaCl). The calculation of mixed ligand complex constants of OHDA shows that the OHDA and amino acids both share the great benefit from the formation of the mixed complexes. Computer simulation of blood plasma model indicates that OHDA acting as a drug ligand does participate in the complicate biological equilibrium of low molecular weight metal complexes disturbing the distribution of essential metal ions--zinc which propably results in changing the activity and function of crucial zinc--containing enzymes. Meanwhile, attention must be paid to the effect of administering OHDAon Cu(Ⅱ) ion balance.
    Studies on Porphyrin Compounds (Ⅷ)--Synthesis and Structure of Diporphyrin Cobalt Complexes
    Huang Su-qiu, Liu Jun, Wang Yu-ting, Jiang Zhao-ci
    1991, 12(2):  153-156. 
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    This paper reports the synthesis of the five diporphyrin compounds linked by diamido groups with different length of aliphatic chains and their cobalt complexes. Their structures are also discussed according to UV, IR, 1HNMR and MS spectra.
    Synthesis and Crystal Structure of the Complex of Bis[4,4,4-Trifluoro-1-(2-Thienyl) Butanedione-1,3] Copper(Ⅱ) with Diquinoline
    Yu Yun-peng, Zhu Duo-lin, Xu Zheng, Gou Shao-hua, You Xiao-zeng, Liu Shi-xiong, Lin Chi-chang
    1991, 12(2):  157-160. 
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    The title compound was synthesized and characterized by elemental analysis, thermo-analy-sis(TG-DTA), 1R and X-ray diffraction analysis.The carystal belongs to triclinic system with a=9. 782(2)Å,6=9. 978(2)Å, c=9. 562(2)Å, α=91.62(2)°, β=111. 09(1)°, γ=104. 75(2)°,V=834. 7A3,Z=1,Dc=1. 52 g·cm-3,Dm=1.51 g·cm-3,M=764. 22, F(000)=387e and the space group is P1.The structure was solved by patterson method and refined by least squares method to final R=0. 045 for 2491 reflections. Cu (Ⅱ) is hexacoordinated and lies on the plane formed by four oxygen atoms, two quinoline molecules with Cu(Ⅱ) form the trans-bis-quinoline addut. The plane CuO4is almost perpendicular to the quinoline ring, the angle between the planes is 93. 8°.
    Studies on Magnetic Circular Dichroism of A New Tailed Porphyrin Iron
    Zhao Dong-yuan, Cao Xi-zhang, Xiu Zheng-kun, Dong Qing-chu
    1991, 12(2):  161-164. 
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    The magnetic circular dichroism spectra of new tailed porphyrin iron complexes, MDMBPTPPFe(Ⅲ)Cl and MDMBPTPPFe(Ⅱ) with a series of axial ligands such as imidazole, pyri-dine,4-methylpyridine, piperidine, Et3N, Et2NH, n-C4H9NH2,n-C3H7NH2, CO, NO, were observed. The MCD of high spin ferric porphyrin complex is type Bwhich is ascribed to the angular momenta induced by the external magentic field, because of appreciable configuration mixings due to the charge-transfer excited states of exactly the same symmetry Eu3. The ligands binding to the five-coordination ferrous porphrin is accompanied by dramatic changes in the visible and soret region of the optical spectrum. The MCD of the mixing axial ligands ferrous porphyrin complexes differs form that of the bisli-gands ferrous prophyrin complexes in the region of 530 to 560 nm because of the difference between the symmetries of the two complexes. The MCD of ferrous porphyrin complexes is type A, which is contributed by the transitions from the nondegenerate ground state to the degenerate excited state.
    Characterization and Structure of Complex of Cadmium with 2-[(o-Hydroxybenzylidene)amino]phenol and Pyridine
    Liu De-xin, Cui Xue-gui, Hao Shu-xuan, Li Feng-ling
    1991, 12(2):  165-168. 
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    Acomplex of cadmium with 2-[(o-hydroxybenzylidene) amino] phenol (H2Sap) and pyri-dine Cd2(C13H9NO2)2(C5H5)6was prepared. Its structure was determined. It is found that the crystal belongs to the monoclinic system with space group P21/c, and the unit cell parameters are:a=14. 006(3)Å, b=10. 362(1)Å, c=18. 435(2)Å,β=111.29(1)°,V=2492. 77Å3M=1121.86, Z=2, DI=1.495g/cm3, μ=9. 023 cm-1, F(000)=1136.The cadmium coordination configuration is octahedral. The properties of the complex have been characterized by IR, NMR, DTA and TGtechniques.
    Separation and Determination of Rare Earth Chelates by High PerformanceLiquid Chromatography Using 4-(2-Pyridylazo) Resorcinolas Chromophoric Reagent
    Gao Jin-zhang, Wang Ji-min, Hu Ping, Bai Guang-bi
    1991, 12(2):  169-172. 
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    A method for separation and determination of nine lanthanides chelates in 12min by using reversed phase ion pair high performance liquid chromatography with 4-(2-pyridylazo) resercinol (PAR) as the chromophoric reagent has been studied. The optimum condition of separation and determination are also described in this paper. The calibration curve is a linear function of concentration in the range of 0. 01 -3. 0 ppm for La, 0. 03-2. 8 ppm for Ce, 0. 06-3. 50 ppm for Nd, 0. 05-3. 8 ppm for Pr, 0. 01 -3. 0 ppm for Sm, 0. 05-3. 40 ppm for Eu, 0. 02-3. 0 ppm for Tb, 0. 01 -3. 4 ppm for Ho and 0. 02-4. 00 ppm for Er. The variational coefficient is found to be less than
    Studies on Chromatographic Characteristics and Mechanism of theSide-chain Oxygen Crown Ethers Polysiloxane as Stationary Phases for Capillary Gas Chromatography
    Wu Cai-ying, Wang Cheng-ming, Zeng Zhao-rui, Lu Xue-ran
    1991, 12(2):  173-176. 
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    Two new kinds of crown ether, n-undecyloxymethyl-18-crown-6(or 15-crown-5) side-chain polysiloxane were prepared and coated on capillary column. Their chromatographic characteristics including column efficiency, allowable operating temperature range, thermal stability, polarity and selectivity were studied, and their separation mechanism was discussed.
    Studies on the Simultaneous Determination of Multicomponent System by Absorption Spectrometry--Determination of Cobalt, Nickel and Copper in TricomponentMixing System by MR and PLS Methods
    Lu Xiao-hua, Zhu Li-hua
    1991, 12(2):  177-179. 
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    The partial least-square (PLS) and multivariable linear regression methods are used in the simultaneous determination of Co, Ni and Cu mixtures. The effects of parameters, the number of calibration samples n, the number of wavelengths p and the latent variables d, on the prediction of results are discussed. The results show that the accuracy of PLSanalysis is superior to that of MR method for determining a multicomponent system in the case of the spectra with a low selectivity.
    Standard Addition Dual Wavelength Spectrophotometry Used for Selective Determination of Manganese
    Lin Hui-gai, Li Meng-long, Shi Learning, Li Zhi-laing, Yu Ru-qin
    1991, 12(2):  180-182. 
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    The two-model standard addtion method was developed for the improvement of selectivity of spectrophotometry. Based on the combination of dual wavelength spectrophotometry and standard addtion method, the standard addtion-dual wavelength spectrophotometry was designed to estimate the concentration of analyte and to eliminate the interference of coexisting species, which could remedy some defects for the two original methods. The proposed method was applied to the determination of manganese(Ⅱ) in the presence of zinc(Ⅱ), with no separation, using the 5-Br-PADAP/triton X-100 chelating system.
    Studies on the Evaporation and Excitation Behaviour of Rare Earth Elements in Ar-N2/D.C.ARC Discharge
    You Xin-guo, Jiang Zu-cheng, Hu Jun, Zen Yun-e
    1991, 12(2):  183-185. 
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    In this paper the investigation of the influence of the discharge medium (Ar-N2, Ar-O2) and their ratio on the line intensities of rare earth elements, spectral background, the evaporation rate of rare earths, the evaporation rate of sample, and excitation temperature was carried out by experimental method; The adequate conclusions are presented.
    Potential Titration on Uncoupled Platinum Electrode
    Xing Bao-zhong, Weng Yun-rong, Zhu Jun-jie, Gao Hong
    1991, 12(2):  186-188. 
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    In this paper, it is shown that the potential titration was carried out on a uncoupled platinum electrode. The platinum eletcrode used as an indication electrode, must should be treated with abasic solution. The change of E-t curves on the end-point was given in the form of peak-shape and could be observed on the oscillograph. This methed was applied to complexometric, precipitating and neutralizing titrations. The accurate results obtained will be significant for the theoretical reseach.
    Synthesis and Spectral Properties of 2,2'-Bisbenzoxazole Derivatives
    Zhou Yi-min, Xia Xiao-ping, Gao Zhen-heng
    1991, 12(2):  189-192. 
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    Sixteen of 2, 2'-bisbenzoxazole derivatives were synthesized, 13 of them are new compounds. Their m. p., IR, UV absorption spectra, fluorescence emission spectra, fluorescence quantum efficiencies and laser conversion efficiencies of the compounds were determined. 2,2'-Bisbenzoxa-zolyl derivatives were compared with l,4-bis(1',3'-benzoxazolyl-2')benzene derivatives and E-1,2-bis(l',3' benzoxazolyl-2')ethene derivatives and the difference of their spectra properties were also discussed.
    Mechanism of Inhibiting Light Fading of Magenta Azomethine Dye by the Antioxidants
    Shi Jun-ying, He Shu-lin, Zheng Zhi-de, Wang Zai-lan, Wang Wen-feng
    1991, 12(2):  193-197. 
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    The interaction between oxygen and magenta azomethine dye was studied by laser flash kinetic spectrophotometry. It was found that the contact charge transfer complex was formed. The light fading of magenta azomethihe dye not only relates to the singlet oxygen, but also possibly to the free radical anion of oxygen. The effect of antioxidants on the excited state of magenta azomethine dye was observed and this verifies the former can quench the excited dye. The mechanism of inhibiting the light fading of magenta azomethine dye by the antioxidants was discussed.
    A New Synthetic method of Bis(η5-Cyclopentadienylchromium Tricarbonyl) Mercury and Its Single Crystal Molecular Structure
    Song Li-cheng, Hu Qing-mei, Yang Wen, Shen Jin-yu
    1991, 12(2):  198-201. 
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    Reaction of η5-cyclopentadienylchromium tricarbonyl sodium with methylmercuric chloride in diglyme at room temperature for 12 h gave bis(η5-cyclopentadienylchromium tricarbonyl) mercury [η5-C5H5Cr(CO)3]2Hg in58% yield. Its structure was fully confirmed by combustion analysis, IR, 1HNMR, MS and X-ray diffraction methods. The crystal belongs to monoclinic space group P21/c. Cell parameters are a=8. 023 (2)Å, b=20. 843(9)Å, c=10. 331 (2)Å; β=96. 00(3)°, V=1718. 2Å3; Z=4. The average Cr-Hg bond length is 2. 655Å. Mercury atom is approximately co-linear with two chromium atoms (<Cr(1)HgCr(2)=171. 12°). Each chromium atom can be viewed as being on the common apex of the pentagonal pyramid constructed from cyclopentadienyl pentagon bottom and the square-based pyramid with the bottom of three carbonyls and one mercury atom.
    The Aklol Condensation of N,N-Diformyl a-Amino Acetophenone with Aromatic Aldehydes and the Crystal Structure of 1,3-Diphenyl-2-formylamino-3-hydroxy-1-propanone
    Han Ying-lin, Hu Hong-wen, Zhou Zhong-yuan, Yu Kai-bei
    1991, 12(2):  202-206. 
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    Five new aldol products were obtained by the condensation of N,N-diformyl a-amino ace-tophenone (1) with aromatic aldehydes in the presence of a catalytic amount of potassium hydroxide in methanol and the crystal and molecular structure of 1, 3-diphenyl-2-formylamino-3-hydroxy-1-propanone(3a) was determined by X-ray crystallography on a four-circle diffractometer. The crystal belongs to space group P1with lattice parameters: a=10. 802(2)Å, 6=11. 088(2)Å, c=14. 395 (3)Å, α=68. 20(1)°, β=69.19(1)°, γ=64. 35(1)°; V=1403. 7(0. 5)Å3; Dc=1. 27 g/cm3. Z=4, F(000)=567. 92(e). The structure was refined by the block-matrix least-squares, the final R=0.046.
    Solvent Effects on the Electronic Spectra of 1,4-Bis (Substituted Phenyl Ethynyl) Benzenes
    Tang Jian-sheng, Huan Zhen-wei, Gao Zhen-heng
    1991, 12(2):  207-209. 
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    The electronic spectra of 1,4-bis(phenyl ethynyl)benzene 1 and 1,4-bis[(4-t-butylphenyl) ethynyl] benzene 2 in fourteen solvents were measured, and the solvent effects were studied by using Linear Regression Program QSAR. It is found that the vmaxUVand vmaxFL of the compounds varied with (n2-1)/(2n2+1), (ε-n2)(2ε-n2)/ε(n2+2)2and (ε-1)/(ε+2)-(n2-1)/(n2+2) of the solvents. The attractive forces between the molecules of the solutes and the molecules of the solvents are mainly dispersion force.
    Studies on the Synthesis and Properties of Siloxane Containing Benzoin Ether Group
    Zhang Xian-liang, Wang Quan, Zhuo Ren-xi
    1991, 12(2):  210-212. 
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    Allyl benzoin alkyl ethers (Ⅰa,b), r-(benzoin alkyl ether) propylcyclotetrasiloxanes (Ⅱa,b), and polysiloxanes containing a pendent benzoin alkyl ether group (Ⅲa,b)were synthesized and structurally characterized. These photoinitiators were used for the curing of polymethyl r-(methacry-loxy) propyl siloxane (Ⅳ). All of the organosiloxane photoinitiators show a good compatibility with the photosensitive polysiloxane(Ⅳ). The cyclotetrasiloxane photoinitiators(Ⅱa,b) exhibit a higher curing speed.
    Studies on Chemical Composition of Volatile Oil of Patrinia Heterophylta Bge.
    Li Zhao-lin, Zhu Jia-liang, Chen Ning, Chen Yao-zu
    1991, 12(2):  213-215. 
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    In this paper, the volatile oil of Patrinia heterophylla Bge. was obtained by the simultaneous steam distillation-solvent extraction, which was carried out in the device designed in our lab. The yield of the oil was 0. 63%. Its chemical composition was studied by capillary gas chromatography-mass spectrometry. Over 50 components were separated, of which 30 compounds composing 56.32% of the oil were identified. The major component, isovaleric acid, was separated by distillation under reduced pressure and identified by MS, IR and NMR.
    The IRC Method in Chemical Reactions (Ⅶ)--Reaction Ergodography for the Cycloaddition of Acetylene and Ethylene
    Pu Qiang, Xia Xin-fu, Zhao Cheng-da, Huang Jing-an, Chen Bin
    1991, 12(2):  216-218. 
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    The reaction mechanism for [2s+2a] cycloaddition of acetylene and ethylene was studied by using ab initio at the RHF/3-21Glevel. The result indicates that this reaction process go through the transformation from the translation of reactant to the vibration of product. Thus, the subtitution effect will have an important influence on such a reaction process. The physically visual picture provided by the IRCanalysis gives a convincing evidence for the Woodward-Hoffmann rule.
    The IRC Method in Chemical Reactions (Ⅷ)--Reaction Ergodography for the Pyrolysis of Methyl Azide
    Chen Bin, Zhao Cheng-da, Fu Qiang, Li Ying-wei
    1991, 12(2):  219-221. 
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    The ab initio calculations were performed on the reaction ergodography for the pyrolysis of methyl azide by the Intrinsic Reaction Coordinate (IRC) method. The potential energy hypersurface and transition state structure were determined at RHF/4-31G level. The IRC analysis indicates that the pyrolysis of methyl azide occured through a 1,2-H shift coupled to N2elimination, but the N2elim-ination is prior to the 1,2-H shift. That is to say, such a reaction process is concerted but nonsyn-chronous. This mechanism can well explain the temperature-dependence of pyrolysis of alkyl azides (H3C)2H3-nC-N3(n=0-2) determined by PEspectra.
    Interaction Between Cationic-Anionic and Nonionic Surfactants in Mixed Aqueous Solutions
    Ding Hui-jun, Hou Xiang-ling, Zhao Guo-xi
    1991, 12(2):  222-226. 
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    Cationic-anionic surfactants have a high surface acivity. But they are liable to precipitate as the concentration is slightly over cmc, so their uses are restricted. This paper describes their various surface properties and solubility phenomena when a nonionic surfactant is added into them. The results indicate that (1) owing to solubilization of nonionic surfactant, the solubility of cationic-anionic surfactants is increased and the surface activity of cationic-anionic surfactant is essentially kept constant under the condition of certain proportions; (2) the interaction between cationic-anionic and nonionic surfactants is very small, they can form nearly an ideal mixed micelle; (3) the cloud points of TX-100(8. 33 × 10-3mol/kg) increase as the concentration of C+C-increases and decrease as the concentration of C+C-goes beyond the cmc.
    A Study on Mechanism of Photochemical Reaction of New Photosensitizer-Sulfonated Aluminum Phthalocyanine
    Chen Shi-ming, Chen Ji-yao, Lu Ya-meng, Cai Huai-xin
    1991, 12(2):  227-230. 
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    The photochemical reaction of sulfonated aluminum phthalocyanine (A1SPC) was studied by ESR spectrometry. By using TMHP as a probe, the intermediates of A1SPC photochemical reaction were detected according to the ESR signal of nitroxyl free radical. It was shown that the formation ofthe nitroxyl free radical--the photooxide of TMHP depends on the presence of oxygen. The results,that the ESR signal is enhanced by deuterated water(D2O), inhibited completely by β-carotene and partially inhibited by cytochrome Cand superoxide dismutase(SOD), show that the singlet oxygen (1O2) is produced and is the main intermediate product.
    A Study of Charge Transfer Between NiPc and Surface-Adsorbed Oxygen and Pyridine
    Liang Yue-xia, Liu Wang, Wang De-jun, Xiao Liang-zhi, Tang Guo-qing, Li Tie-jin
    1991, 12(2):  231-234. 
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    In this paper, the effects of adsorption of O2and pyridine on the photovoltaic properties of NiPc was studied by surface photovoltage spectroscopy. Avery weak photovoltaic response band near 450 nm was observed for the first time besides three strong bands near 335, 580 and 650 nm(Bb and and Qband), and was assigned to the charge transfer transition from the dπ orbital of central metal ion Ni2+to the eg(πn) orbital of PCring. In the presence of O2, the three strong bands slightly decreased in intensity, but the weak band disappeared and even reversed. Unlike O2, the adsorption of pyridine can make all photovoltaic response bands of NiPc disappear, but no reversed band was observed. The above results show the charge transfer interaction between NiPc and surface electron acceptors.
    Kinetics of Ion Exchange Reaction of Transition Metals on Stannic Antimonylpyrophosphate Cation Exchanger
    Guo Peng, Liu Jin-chun, Liu Liang-bin, Cheng Jie-ke
    1991, 12(2):  235-238. 
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    The Nernst-Planck equations were applied to the study of the ion exchange reaction kinetics for the transition metal ions(Co2+, Cu2+, Zn2+and Cd2+) with H+-ions on stannic antimonylpy-rophosphate(SSbPP). Under the control of particle diffusion, the rate of exchange has been found to be independent of the metal ion concentration at and above 0. 050 mol/L. The self-diffusion coefficients (D0), the activation energies(Ea) and the entropies of activation (△S*) of transition metal ions have also been calculated by solving Nernst-Planck equations with Apple-II computer. These parameters are useful for predicting the ion exchange mechanism taking place on SSbPP.
    Studies on the Phase Diagram of SmI2-KI Binary System
    Wang Xiao-dong, Wang Shi-hua
    1991, 12(2):  239-242. 
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    The isopiestic phase diagram of SmI2-KIbinary system, the properties and structures of KSm2I5, K2SmI4in the system were studied by DTA and X-ray powder diffraction methods. According to J. Kutscher's view point for discussing REX3-AX(RE=Rare earth metals, A=alkali metals), the formation rules of compounds in the SmI2-KI and YbI2-KI(A=Na, K, Rb, Cs)systems are discussed.
    Preparation and Behaviour of Cobalt Hexacyanoferrate Film Electrode
    Wang Guang-qing, Gao Zhi-qiang, Zhao Zao-fan
    1991, 12(2):  243-247. 
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    The very stable cobalt hexacyanoferrate film electrodes (CHCF/GC) were prepared, which can undergo successively over 10000 cycles of potential sweep between -1. 0 V and + 0. 9 V(vs SCE). Various factors which affect the voltammetry of CHCF film electrodes and the charge transport process of the electrodes are discussed. The size of the hydrated cations, the concentration of electrolyte and the swelling property of the film in the solvent have significant effects on voltammetry of CHCF film electrodes. Electrocatalysis of CHCF film electrode to Fe3+/Fe2+is also discussed.
    Studies on the State-Selected Reaction of H+H2(v) and Its Isotopic Analogues by Variational Transition State Theory
    Ju Guan-zhi, Yang Yu-wei, Deng Cong-hao
    1991, 12(2):  248-252. 
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    In this paper, the variational transition state theory is extended to calculate the state-selected reaction rate constants for an arbitrarily assigned vibrational excited reactants and their transition state. The extended theory can be used to calculate the rate constants for a series reactions of H+H2(v) and its isotopic analogues through different vibrational excited transition states. In comparison of the calculated results with experimental values, it is found that the results obtained by the exciting bend vibration modes are nuch close to the experimental values. It is also first obtained that when an energy is given, the exciting transition state's bend modes are more favourable to the reactions than the exciting stretch ones.
    A Study of the Effect of Alkyl Group on the Reactivity of Carbonyl Compounds by CNDO/2
    Huang Liu-shu
    1991, 12(2):  253-255. 
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    According to the results of CNDO/2, this paper considers that the positive charge of the car-boxylic carbon increases under the influence of alkyl group. This is in agreement with the rule that alkyl groups have the a-electron repulsing effect. The frontier orbital method is used to explanin that alkyl group reduces reactivity of carbonyl group.
    Studies on Electronic Energy Band and Doping Conducting Mechanism of PMT by Quantum Chemistry
    Hou Yang, Fu Yu-jie, Wang Hui-zhong, Wang Rong-shun, Zhao Cheng-da
    1991, 12(2):  256-258. 
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    The electronic energy bands of poly-m-toluidine(PMT) and polyaniline(PAn) doped before and after with proton acid were calculated by EHMO-COmethod and the atomic charge distribution, valence bands and band gap were made a comparison between PMT and PAn. The effect of substituent has been discussed by quantum chemistry. The calculation results support the hypothesis of electric conducting mechanism of a polaron conduction band.
    Studies on the Characteristics of Metastable Zone of the Aqueous K2SO4Solution (Ⅲ)--The Induction Period of Nucleation
    Wang Zi-chen, Zhang Li-hua, Yang Yong-hua, Zhao Mu-yu
    1991, 12(2):  259-261. 
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    The induction periods of nucleation for the aqueous K2SO4solution were measured. It can be concluded that the value of nucieation kinetics exponent m provided by the measurements of metastable zone widths is in better agreement with that obtained by measuring the induction periods of nucleation. At the low supersaturation region, experimental results deviate from the theoretical characteristics of homogeneous nucleation. The results seem to indicate that at low supersaturation region(S<1. 08), the heterogeneous nucteation mechanism is dominant. In the high supersaturation region(S>1.1),the homogeneous nucleation becomes the rate-controlling step.
    Electrocatalysis of Pyrochlore Oxides for Oxygen Electrode Reaction
    Yang Yi-fu, Zhou Yun-hong, Zha Quan-xing
    1991, 12(2):  262-264. 
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    Pyrochlore oxides (Pb2Ru2-x-ySbxPby)O7-z, 0≤x≤1, 0≤y≤1, 0≤z≤0. 5) are a new kind of bifunctional oxygen electrode catalysts. These oxides possess good electrocatalytic properties for both reduction and generation of oxygen in alkaline electrolyte at room temperature. The number of electrons involved in oxygen reduction process were found to be about 3. 55. Tafel slop involved in oxygen generation is 28 mV.
    Studies on Deposition of Silicon Film by Laser-Plasma-Induced Dissociation of SiCl4
    Zhang Jie, Zhang Chang-yan, Lin En-hui, Li Yan-ling, Qiu Ming-xin, Lu Xue-biao
    1991, 12(2):  265-266. 
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    Silicon film was first deposited on a quartz substrate by laser-plasma-induced dissociation of SiCl4. The characteristics of the film obtained is compared with that from laser deposition of SiH4in some references.
    Studies of Liquid Film Diffusion Mass Transfer in the Process of Ion Exchange (I)
    Chang Zheng, Qiu Ling, Lin Xue, He Bing-lin
    1991, 12(2):  267-270. 
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    The liquid film diffusion mass transfer of adsorption of AuCl4- from hydrochloric acid with various concentrations through the film encompassing macroporous crosslinked polymethacrylate resin MET-802 was studied. The results, deviated from the theoretical formula proposed by James J. Car-berry, show that the mass transfer coefficient Kf is in proportion to v7.4(v is kinematic viscosity) and the thickness of the film a is much larger than the diameter of the resin. The above results are discussed and two general empirical equations for expressing Kfand σ are suggested.
    Studies on Polyether-Polyurethane/Polymethyl Methacrylate Interpenetrating Polymer Networks
    Li Yu-wei, Yuan Sheng-hui, Wang Jing-yuan, Tang Xin-yi
    1991, 12(2):  271-275. 
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    In this article we determined the stress-strain, morphology and mechanical properties of interpenetrating polymer networks of PE-PU/PMMA. The effect of the crosslinking, chain extending and intercrosslinking agent and the compositional ratio of PE-PU/PMMAon the mechanical properties were invesitgated. The results show that the sample with the composition ratio of PE-PU/PMMA=25/75 exhibits the highest mechanical properties which has a yield point and hehaves like leathery materials. The results of the dynamic mechnical properties and morphology show that a great phase separation occurs in this system. The compatibility of the two composition is remarkably improved by adding chain extending agent and intercrosslinking agent.
    UV-Vis Spectral Studies of 1,2-Polymerization System of Butadiene Catalized by Molybdenum Tetrachloride
    Chen Dian-bao, Kong Xian-si, Liu Li, Tang Xue-ming
    1991, 12(2):  276-280. 
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    MoCl4in ethyl acetate is of a brown-red color and paramagnetism, which is the result of three absorption bands in the red and blue parts of the spectrum due to the d-d spin-allowed transtition. The change in the types of ligands attached to Mo(Ⅳ), such as C-, C8H17O-, PhO-, Bd, C8H17OH, PhOH and CH3COOC2H5, has no influence on the position of the absorption band. The peak-value of characteristic absorption band of Mo (Ⅳ) complex at 512 nm varies with the amount of cocatalyst added into Mo-Al system. The disappearance of the characteristic absorption band implies that Mo(Ⅳ) is reduced to a low-valency state Mo(Ⅲ). The reduction of Mo(Ⅳ) is improved and the catalytic activity is raised in the aging catalyst system MoCl4-2(OC8H17)2-Bd-Al(i-Bu)2OPhCH3.
    Studies on Catalytic Characteristic of Mimetic Peroxidase
    Sun Shu-sheng, Wang Chun-hai
    1991, 12(2):  281-283. 
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    Amimetic peroxidase, chelate of manganese with tetrakis (3-N-methylpyridyl)-porphyrin was synthesized, and its catalytic characteristic of chromogenic reaction of hydrogen peroxide with 4-aminoantipyrine and N,N-diethylaniline was investigated. Asensitive spectrophotometric method for the determination of trace hydrogen peroxide is developed. The glucose in human serum was determined by the proposed reaction combining with glucose oxidase system with satisfactory results.
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