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    24 January 2001, Volume 22 Issue 1
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    Articles
    Luminescence Properties of YTaO4:Nb,Eu
    LI Bo, GU Zhen-Nan, LIN Jian-Hua, SU Mian-Zeng
    2001, 22(1):  1-5. 
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    Aseries of Y1-x Eux Ta1-y Nby O4 ( x =0—0.20, y =0—1.00) are synthesized by a modified solid state reaction method. When the concentration of NbO43- in yttrium tantalate is low, the structure of these systems is M' type YTaO4. With increasing concentration of NbO43-, its structure completely changed from M' type YTaO4 to fergusonite YNbO4. Under UVexcitation, the emission spectra of YTaO4:Nb,Eu consist of two parts, the emission band between 300—450 nm is the charge transfer emission of NbO43-, and the sharp line emissions in the range of 500—720 nm originate from the transition of electrons in 4f shell of Eu 3+. The main peak at 612.7 nm can be ascribed to the Eu 3+5 D0→ 7F2 transition and shows a strong red emission. Fixing the concentration of Nb 5+ and Eu 3+ separately, and changing the concentration of another ions, the luminescent properties of Y1-x Eux Ta1-y Nby O4 will change rapidly. The difference of luminescence is originated from different structures. The excitation spectra of NbO43- emission ( λ =400 nm) in YTa 0.98 Nb0.02 O4 is a strong excitation band peak at 235 nm. In fact, the band is composed of charge transfer excitation of TaO43- and charge transfer excitation of NbO43-. The excitation spectra of Eu 3+5D0→ 7F2 transition emission have two parts, the sharp lines between300—600 nm and wide band between200—300 nm. The sharp lines originate from Eu 3+ f-f electron transitions, and the wide band includes both charge transfer excitation of TaO43- and NbO43-, and charge transfer excitation of Eu 3+. The excitation spectra of NbO43- emission ( λ =400 nm) in Y0.99 Eu0.01 Ta0.98 Nb0.02 O4 is also a strong band, in which there also exists a charge transfer excitation of TaO43- and a charge transfer excitation of NbO43-. The strong evidence from excitation spectra, emission spectra of this system show that there is a energy transfer from host lattice to activator in the process of luminescence.
    Preparation of Self-doped La1-x MnO3+δ Polycrystalline by Electrochemical Deposition
    HUANG Yun-Hui, WANG Zhe-Ming, ZHU Tao, CHEN Xing, LIAO Chun-Sheng, YAN Chun-Hua
    2001, 22(1):  6-9. 
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    The perovskite-type self doped La1-x MnO 3+ δ was prepared by heat treatment of the gel precursor deposited on a Pt electrode in solutions containing both La 3+ and Mn 2+ ions using catholic reduction electrochemical method. The influence of molar ratio of La 3+ and Mn 2+ in solution, deposition potential and current density on product composition was investigated. Our results indicate that varying the ratio of La 3+ and Mn 2+ in solution, deposition potential or current density can conveniently control the product composition, lattice deficiencies and hence the self-doping level x. In addition, the transport properties are mainly influenced by Mn 4+ content and ion vacancies for the self-doped manganites.
    Synthesis of Ultrafine Zeolite NaY(Ⅱ)——Effect of Complexing Agent
    CHAO Zi-Sheng, LIN Hai-Qiang, CHEN Guo-Zhou, WU Ting-Hua, WAN Hui-Lin, MIN EN Ze
    2001, 22(1):  10-15. 
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    Ultrafine zeolite NaYwas hydrothermally synthesized with silica sol and Al2(SO4)3 as silica and alumina sources, respectively, by adding complexing agent such as citrate, acetate or editate to synthesis batch. The effect of the amount of citrate on the crystallization rate, SiO2/Al2O3 ratio and crystal size of as synthesized zeolite NaYwas investigated. When the relatively lower amount of citrate[ n (citrate): n (Al2O3) ≤2:1] was added, both the crystallization rate and the SiO2/Al2O3 ratio increased while the crystal size reduced obviously comparing with that in the absence of citrate. This indicates that the nucleation and crystallization of zeolite NaYwas promoted by complexing agent. When the relatively higher amount of citrate[ n (citrate): n (Al2O3)>2:1] was added, the above promotion effect diminished. The crystallization rate was found to reduce comparing with that in the absence of citrate, although the crystal size was still smaller than that in the later case. The optimum amount of citrate added to batch appears to be at the citrate:Al2O3 molar ratio of 1.5:1. The similar promotion effect was also observed both for the addition of editate and acetate with the molar ratio of editate:Al2O3 and acetate:Al2O3 equal to 1.5, respectively. The promotion effect of complexing agents to the nucleation and crystallization of zeolite NaYwas related with their complexing ability to aluminum.
    Synthesis of Tetra(4-n-decanoyloxyphenyl)porphyrin Complexes and Fourier Transform Infrared Photoacoustic Spectra
    LIU Wei, SHI Tong-Shun, AN Qing-Da, YANG Da-Zhi
    2001, 22(1):  16-20. 
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    Six complexes of tetra(4-n-octanoyloxyphenyl)porphyins with Mn(Ⅲ), Fe(Ⅲ), Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ) and Zn(Ⅱ) have been synthesized in mixed solvents CH2Cl 2+DMF. The complexes were determined by elemental analysis, UV-Vis, FTIRphotoacoustic spectrum, 1H NMRand molar conductivity measurement. The domains of stability and the structure of the liquid crystalline phases are determined by optical microscopy and differential scanning calorimerials(DSC). The fourier transform infrared photoacoustic spectra of TDPPH2 and its complexes in the range of 3600—190 cm-1 were measured and investigated.
    Binding Equilibrium Study Between La(Ⅲ) and HSA or BSA
    LIANG Hong, BIAN He-Dong, TU Chu-Qiao, SHEN Pan-Wen
    2001, 22(1):  21-25. 
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    The binding of La(Ⅲ) to human serum albumin (HSA) or bovine serum albumin(BSA) has been studied by equilibrium dialysis at pH6.3. The results from Scatchard plots indicate that there are two strong sites and eight weak sites in HSA and two strong sites and six weak sites in BSA, respectively. The results of La(Ⅲ)competing with Cu(Ⅱ), Zn(Ⅱ), Cd(Ⅱ) for binding to HSAor BS Asuggest that one of the strong binding sites is most probably coordinated with atoms which are almost all oxygen. The successive stability constants which are reported for the first time are obtained by non-linear least square method fitting Bjerrum formula. For both La(Ⅲ)-HSA and La(Ⅲ)-BSA systems, the order of magnitude of K1 was found to be 104. The analyses of Hill coefficient and free energy coupling show that some negative cooperative effect was found in both La(Ⅲ)-HSA and La(Ⅲ)-BSA systems.
    Spectroscopic Studies on the Binding of Lanthanides to the Apolactoferrin
    ZHU Bing, DU Xiu-Lian, LI Rong-Chang, WANG Kui, JIN Jian, WANG Bo-Cheng
    2001, 22(1):  26-30. 
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    The binding of Tb 3+ and Eu 3+ to apolactoferrin has been studied on the basis of the changes in differential UV, fluorescence and CDspectra. It was found that Tb 3+ and Eu 3+ are able to bind to two ferric binding sites and the corresponding conditional equilibrium constants for the Tb 3+ binding were determined to be lg K1=8.48±0.24, lg K2=6.72±0.18(0.10 mol/L NaCl, 0.10 mol/L Hepes, pH7.4 and 25 ℃),but Tb 3+ can not displace the ferric ions from lactoferrin. By lower Tb 3+ /Lf ratio, the conformation became more compact with tryptophane residues exposed to more hydrophobic environment. When more Tb 3+ bound to Lf, the conformation changed in other direction. Anyhow, Tb 3+ binding did not affect the secondary structure.
    Synthesis and Characterization of Long Chain Alkyl Costa-type Organocobalt Complexes and Their Inclusion Interaction with β-CD
    SHEN Xu-Jie, XIANG Ping, CHEN Hui-Lan
    2001, 22(1):  31-33. 
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    Two long carbon chain alkyl (aqua) Costa-type organocobalt complexes (R=C6H13 and C8H17 ) have been synthesized for the first time and characterized by elemental analysis, UV-Vis and 1H NMR. Their inclusion behavior with β-cyclodextrin was studied by 1H NMRmethods. It was indicated that in aqueous solution supramolecular adducts have been formed, in which the alkyl groups of the guests were included into the cavity of β-CD. Cyclic voltammetry methods was also used to study the electrochemical properties of organocobalt complexes in the absence and presence of β-CD.
    Studies on Quantum Dots-labeled Trichosanthin
    ZHANG Chun-Yang, MA Hui, DING Yao, JIN Lei, CHEN Die-Yan, MAO Pi, NIE Shu-Ming
    2001, 22(1):  34-37. 
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    Semiconductor quantum dots were used for the first time to label trichosanthin. The absorption spectrum, fluorescent spectrum and enzymatic activity of quantum dots-labeled trichosanthin were studied in this paper. The absorbane of QDs-TCSvaried to a less extent with wavelength in the range of 400-600 nm. The fluorescent spectrum of QDs-TCSunderwent a blue-shift in the emission peak, but the intrinsic spectral width was unchanged. No changes were found in the enzymatic activity of QDs-TCSin comparison with trichosanthin. Distribution of QDs-TCSwithin human choriocarcinoma cells was simultaneously observed with two-photon laser scanning microscopy and confocal laser scanning microscopy. The results indicated that QDs-TCScould enter the cytoplasm across the membrane and aggregated around the nuleolus.
    An Optode Membrane for CO2 Based on Fluorescence Quenching of the Inclusion Complex of Cyclodextrin and Porphyrin
    YANG Rong-Hua, WANG Ke-Min, XAIO Dan, ZHANG Liu-De, YANG Xiao-Hai
    2001, 22(1):  38-42. 
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    Heptakis(2,6-di-O-isobutyl)-β-cyclodextrin(DOB-β-CD) is able to increase the fluorescence of meso-tetra(4-methoxylphenyl)porphyrin(TMOPP) immobilized in plasticized PVCmembrane, and the fluorescence is quenched by carbon dioxide in aqueous solution. Based on this mechanism, a fluorescence sensing membrane has been developed for the determination of carbon dioxide in aqueous solution. The optimal membrane consists of 2 mg of TMOPP, 8 mg of DOB-β-CD, 50 mg of PVCand 100 mg of bis(2-ethylhexyl)sebate (DOS). With the optimal condition described, carbon dioxide in solution from 475×10-7 to 39×10-5 mol/Lcan be determined. Besides a high reproducibility of the optical signals, the very short response time less than 30s is realized. The sensor exhibits a good selectivity over some common ions.
    High Performance Liquid Chromatography Analysis of D-Ribose Content in Glucose Zymotic Fluid
    ZHANG Jin-Feng, WANG Jian-Gang, DENG Guo-Cai, YANG Si-Hai, CHEN Rong-Ti
    2001, 22(1):  43-45. 
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    The method has been put forward to analyze the content of D-ribose obtained from glucose zymotic fluid. D-ribose was determined by HPLC, on a Sugar PakⅠcolumn, by using a refractive index detector and a mobile phase of pure water. We have also studied the separation conditions of sugars. It has many advantages, such as rapid analysis, high sensitivity and high precision and good reproducibility. The recovery of D-ribose were 95.5%—104%, RSDwere less than 1.5%, the detection limit of D-Ribose was 50 ng.
    TLC-FT-SERS Study on a Pair Isomer in Uncaria Rhynchophylla Jacks Alkali
    WANG Yuan, WANG Song-Ying, ZHAO Yi-Xue, ZI Feng-Lan, WANG Ying-Feng, WANG Hong-Jie, ZHANG Jing-Bing
    2001, 22(1):  46-48. 
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    Anew method for analysing the ingredients of rhynchophylline and isrhynchophylline in Uncaria Rhynchophylla Jacks using hyphenaed high efficiency thin layer chromatographic(TLC) and the surface-enhanced raman spectroscopic(SERS) technics is reported. The results show that the characteristic spectral bands of rhynchophylline can be obtained from the TLCspot with minimum amount of rhynchophylline sample of about 25 mm diameter. The difference between the SERSand solid spectra are found. Spectral band at 1397 cm-1 was obtained wits great enhanced want. Molecule was absorbed in surface silver sol by pair of electrons in —OCH3. Isrhynchophylline sample spectrum band at 1615 cm-1 obtained the greatest enhance. Isrhynchophylline molecule was absorbed in surface silver sol by pair of electron at Natom in ring indole. An absorption model of rhynchophylline and isrhynchophylline and silver sol is proposed. That effective combination of TLCand SERScan be used to analyse the chemical ingredients with high sensitivity.
    Preparation and Electrochemical Behavior of Eu(Ⅲ)-Calix-2Ar Arene Film Modified Electrode
    CHEN Yong, LI Hai-Bing, WANG Chang-Fa, CHEN Yuan-Yin
    2001, 22(1):  49-51. 
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    The Eu(Ⅲ) with 25,27-dibenzyloxy-5,11,17,23-tetra-tert-butyl-26,28-dihydroxycalix[4]-arene film electrode(Eu(Ⅲ)-Calix-2Ar/GC) was firstly prepared. Cyclic voltammetric experiments showed that, in NaClO4 solution, the film electrode has one pair of well defined and relatively stable reduction and oxidation peak. For this pair of peak, Epc=-0.69 Vand Epa= -047 V(vs. SCE). Various factors which affect the voltammetry of Eu(Ⅲ)-Calix-2Ar film electrode and the charge transport process of the electrode are discussed. Research showed that the voltammetry of the film electrode is affected by the concentration of supporting electrolyte,the film thickness, solvent and the film has some properties of supramolecular system.
    Newborn Screening of Phenylketonuria by GC-CI-MS-SIM
    DENG Chun-Hui, HU Yao-Ming, HU Ke-Ji, ZHANG Ya-Fen, GU Xue-Fan
    2001, 22(1):  52-54. 
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    The application of MSin newborn screening is one of the most important branches of MS's current clinical application. In this paper we first reported a new method of newborn screening for Phenylketonuria (PKU) by GC-CI-MS-SIM, which was relatively cheap, fast, sensitive and accurate. In this method Phenylalanine (Phe) and Tyrosine (Tyr) were extracted from dry blood spots with 0.1% mol/L HCl-methanol. The protein in the extraction was gotten rid of by centrifugor. Phe and Tyr were reacted with 30 mol/L HCl-butanol, then the products Phe and Tyr butyl esters were reacted with trifluoroacetic anhydride. The final derivations from Phe and Tyr, alanine, 3-phenyl-N-(trifluoroacetyl)-, butyl este and L-tyrosine, N(trifluoroacetyl)-, butyl ester, trifl were analyzed by GC-CI-MS-SIM. The contents of the two amino acids in blood samples were determined by calculating the areas of their final derivations with exterior standard. Finally, the molar ratios of Phe to Tyr in blood sample were calculated as the basis of PKUdiagnosis. Because chemical ionization and selective ion measurement were used in this method, the limits of detection for Phe and Tyr were low and the sensitivity was excellent. About 30 blood samples were analyzed by this method, and the results prove that this method could successfully discriminate between normal infants and PKUpositive ones. The price of instrument GC-MSis cheaper than that of MS-MS. Therefore it was capable for large-scale screening in developing countries.
    Theoretical Study on Secondary Chemical Bond in Organo-metallic Compounds(Ⅴ) Study on Formation of Secondary Chemical Bond by Molecular Mechanics Method
    JIANG Ping, SHI Jing, SUN Hong-Wei, YUAN Man-Xue, LAI Cheng-Ming
    2001, 22(1):  55-58. 
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    In this paper, the steric energies of the following molecule pairs are discussed and compared by means of the molecular mechanics method, (1) cis- and trans-: ClHgCHCHCl(Ⅰ), ClHgCHCHHgCl(Ⅱ), ClCHCHCl(Ⅲ). The energy orders are Ecis-Ⅰ < Etrans-Ⅰ, Ecis-Ⅱ> Etrans-Ⅱ, Ecis-Ⅲ > Etrans-Ⅲ; (2) o- and m-: C6H4HgCl2(Ⅳ), C6H4Hg2Cl2(Ⅴ), C6H4Cl2(Ⅵ), the energy orders are Eo-Ⅳ < Em-Ⅳ, Em-Ⅴ > Eo-Ⅴ, Eo-Ⅵ > Em-Ⅵ. From the energy barriers of internal rotations of the following molecules, ClHgCH2CH2Y, Y=CN(Ⅶ), C6H5(ⅩⅠ), the energies of cis-molecules(Ⅶ, ⅩⅠ), are lower than those of trans-ones. The energies would be increased when we changed _Hg_Cl into _Cl or _CN. From above calculation, we concluded that there are secondary chemical bonds in such an organo-metallic compounds as cis-Ⅰ, o-Ⅳ, Ⅶa, ⅩⅠa. The formation of secondary bond can decrease the molecules energies.
    The Pocket Effect of Extraction of Iron(Ⅲ) from Sulphuric Acid Solution with Primary Amine N1923
    LI Xue-Mei, YANG Yong-Hui, SHAO Hua, SUN Si-Xiu, LIU Zhao-Ping, ZHONG Hong-Mei
    2001, 22(1):  59-62. 
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    The extraction of iron(Ⅲ) from sulfuric acid media by primary amine N1923 was investigated. The pocket effect was proposed for the first time by using IRspectra and TEM. When the concentration of extractant reached to 0.05 mol/L, primary amine N1923 formed the spherical reversed micelle, which could improve the distribution coefficient of extraction greatly, and the pocket effect emerged. The whole action of extraction contained the two kinds of mechanism, ionic complex extraction and micelle solubilization, the extraction equation can be showed as follows: D=K1c(N1923)+K2cm(N1923)
    Total Synthesis of Two Neolignans for (±)-Eusiderin E and (±)-Eusiderin F
    JING Xiao-Bi, GU Wen-Xin, BIE Ping-Yan, REN Xin-Feng, PAN Xin-Fu
    2001, 22(1):  63-66. 
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    (±)-Eusiderin Eand (±)-Eusiderin F, two neolignans, were first synthesized from pyrogallol, in which route the Claisen Rearrangement was used to afford four C6_C3 units 2,6-dimethoxy-3-allyl-phenol(5), 1-(3,5-dimethoxy-4-hydroxy-phenol)propene(6), 3-methoxy-5-allyl-1,2-benzene-diol(9), 1-(5-methoxy-3,4-dihydroxy-phenol)propene(10).
    Studies on Imitation of SOD by N-Dodecanoyl-glycylglycinato-cuprate(Ⅱ)
    XIE Ying, ZHOU Xuan, WANG Jun-Bo, LI Feng-Mei, DENG Xi-Xian
    2001, 22(1):  67-69. 
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    Anew kind of analogues of SOD(N-dodecacyl-glycylglycinato)-cuprate(Ⅱ) [Cu(C12-Gly-Gly)] and di-[N-dodecacyl-glyglycinate-cuprate(Ⅱ)][Cu(C12-Gly-Gly)2] were prepared. Their SODlike activities were studied by using pulse radiolysis. It was found that the SODlike activity would be improved through adding long chain on Gly-Gly, and close to the natural SOD. The new complexes achieved to imitate SODas a whole.
    First Enantioselective Syntheses of (2R,3R)- and (2S,3S)-3-(4-Hydroxy-3- methoxyphenyl)-2-hydroxymethyl-1,4-benzodioxan-6-carbaldehyde
    GU Wen-Xin, WU Tong-Xing, CHEN Xiao-Chuan, PAN Xin-Fu
    2001, 22(1):  70-71. 
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    An enantioselective and regioselective total synthesis approach to chiral 1,4-benzodioxane lignans(2R,3R)- and (2S,3S)-2-(4-hydroxy-3-methoxyphenyl)-3-hydroxymethyl-1,4-benzodioxan-6-carbaldehyde was reported firstly.
    Crystal Structure Study of2-Thiazolidines
    HAN Jia-Xiang, PU Min-Li, YUAN De-Kai, YAO Xin-Kan
    2001, 22(1):  72-74. 
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    Aseries of 2-phenyliminothiazolidines has been successfully synthesized; and 2-(2-methylphenyl)iminothiazolidine(Ⅰa) and 2-(4-methylphenyl) iminothiazolidine(Ⅰb) have been selected to determine their crystal structures by X-ray diffraction technique, from their molecular graph of it is shown that double bond at 2-carbon atom of the heterocycle is all extro-cyclic at the crystal state, and there are two main plaines in Ⅰa and Ⅰb. But in Ⅰa, the angle between the planes is 61.4° and in Ⅰb the angle is about 41.4°. And so there is a strong conjugative effect in Ⅰb than in Ⅰa. So it is thought that the difference in fungicidal activies between 2-substitutedphenyl compounds(Ⅰa) and 4-substitutedphenyl compounds(Ⅰb) is due to their space factors.
    Studies on the Carbonylation of Carbon Dioxide Under Single Wavelength Visible Light Irradiation
    ZHUANG Jian-Qin, YIN Jing-Mei, GAO Da-Bin, ZHENG Xue-Fang, ZHOU Guang-Yun, ZHOU Ning-Zhang, WANG Xiang-Sheng, GUO Xin-Wen
    2001, 22(1):  75-77. 
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    It is the first time to report the carbonylation of cyclohexene with carbon dioxide under ambient conditions irradiated at single wavelength visible light.The effects of catalysts, the additives and different wavelength have been investigated, which indicated that the metal complexes such as CoTPPand MnTPPacted as catalyst of the carbonylation as well as sensitizer under the irradiation of special wavelength visible light. Furthermore, when adding sodium proponiate to the solution, the catalysts such as PCFe would be activated and the formation of ester was promoted obviously. We also detected the quantum yield of this reaction, and found it can reach to 10-2. As far as the quantum yield and taking good advantage of the energy from solar was concerned. HSO3PCCo was the better catalyst for the carbonylation.
    Michael Addition-elimination Reactions of Chiral-5-Alkoxy-3,4-dihalo-2(5H)-Furanones in DMF
    LI Xue-Qiang, GONG Bo-Lin, WANG Feng-Rong, CHEN Qing-Hua, WANG Zhi-Dan
    2001, 22(1):  78-80. 
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    In this paper, we report the tandem Michael addition-elimination reactions of chiral 5-alkoxy-3,4-dihalo-2(5H)-furanones with DMF by the catalyst of metal sodium. The optically pure 5-(S)-alkoxy-4-N,N-dimethyl-3-halo-2(5H)-furanones 6a-6d were identified on the basis of their analytical data, such as [α]D20, UV, IR, 1H NMR, 13C NMR, MSand elemental analysis.
    Influence of the Computation Conditions on the Results in Density Functional Calculations
    MO Yi, LI Le-Min
    2001, 22(1):  81-85. 
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    The influence of the computation conditions on the results in the calculations with Kohn-Sham density functional theory has been studied through a series of calculations on the molecules with various compositions and structures such as BCl3, SO2, ZnO, TiCl4, LuF3. Three factors are considered. It is found that the completeness of the basis sets is the most important factor. The number of the grid points of the numerical integration is less important. The projection for decomposing the molecular charge into multipolar components centered in each atomic nucleus converges fairly rapidly. The molecular geometry and the fundamental vibrational frequency are insensitive to the computation conditions, while the total energy and bond energy are pretty sensitive. If the same basis set and the same numerical integration points are used for a molecule and its constituting atoms in calculating its bond energy, the error of the calculated result could be reduced. It is shown that the calculation results with an accuracy matched with the approximate DFTformulas can be obtained by choosing the mediate computation conditions with a smaller computational effort.
    A Quantum Chemistry Study on the Electronic Structure of Mercapto Flotation Reagents and Its Coordination with Metal Ions
    YANG Gang, LONG Xiang-Yun
    2001, 22(1):  86-90. 
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    The electronic structure of mercapto flotation reagents MBT, MBO, MBMwas calculated by use of a quantum chemistry program package, MOAN. As a results, the experiment factors for the stability of isomers of these flotation reagents were explained: the activity site and the role played by benzene ring were discussed and some reasons for that N, O, Son pentahetero ring do not act as a reaction site when coordinating with M(Ⅱ) were also found. Furthermore, the interactions between species above and Pb(Ⅱ), Zn(Ⅱ) as well as some of transition metal ions, Pt(Ⅱ), Fe(Ⅱ), Cu(Ⅱ), were also calculated and discussed here.
    Preparation of Carbon-coated Iron Carbide Nanocrystals by Using AC Carbon Arc Discharge Method
    ZHANG Xun-Gao, JIANG Ming, LIU Ying, HAO Guang-Ming, XU Zhi-San, ZHU Ling, SHENG Rong-Sheng
    2001, 22(1):  91-94. 
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    Ahighly effective method for preparation of carbon-coated iron carbide nanocrystals by ACcarbon arc discharge was studied, the yield of magnetic micro powder was over 90%. The result of thermogravometric analyses(TG)(>800 ℃, O2, 5 ℃/min) indicated that there was 17.5% of Fe wrapped by graphite carbon in the magnetic micro powder. The structural characterization by X-ray diffraction(XRD) and transmission electron microscopy(TEM) revealed that Fe3C and Fe5C2 particles were wrapped by graphite carbon, no evidence of α-Fe was observed. The size of the wrapped iron carbide particles was typically in the range 3—10 nm. The formation mechanism of carbon-coated iron carbide nanocrystals was discussed. The magnetic hysteresis loop(B-H) at room temperature was investigated, it showed that Bs=2.6×10-2 T, Br=2.5×10-3 T, Br/Bs=9.7%, Hc=5.52 kA/m.
    Studies on Electrochemical Properties of Tetrahydrocarbonthia- tetrathiafulvalenes and Their Three-dimensional Quantitative Structure-property Relationship(3D-QSPR)
    LI Hua, TIAN Min, ZHANG Si-Chun, GAO Hong
    2001, 22(1):  95-98. 
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    Three-dimensional quantitative structure-property relationship(3D-QSPR) and comparative molecular field analysis(CoMFA) have been applied to elucidating the correlation of the structures of tetrahydrocarbonthia-tetrathiafulvalenes(TTF) and their electrochemical properties. Six new π-donor TTFmolecules are prepared and their electrochemical properties have also been investigated by cyclic voltammogram. CoMFAresulted in a quantitative description of major steric and electrostatic field effects, and gave significant new insights to the factors governing electrochemical properties. The model was used to predict the half-wave potentials of TTFwith satisfactory results.
    Raman Spectroscopy of Supersaturated Aqueous Solution of Borate
    JIA Yong-Zhong, GAO Shi-Yang, XIA Shu-Ping, LI Jun, LI Wu
    2001, 22(1):  99-103. 
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    Supersaturated aqueous solution of MgO·2B2O3-H2O, Na2O·5B2O3-H2Oand MgO·3B2O3-H2Owere prepared. Raman spectra of the solutions have been obtained. The results show that there exist various polyborate anions in the supersaturated aqueous solutions. The assignments of the recorded frequencies of the borate aqueous solution were given. The interaction mechanism between polyborate ions in supersaturated solution was discussed.
    Organic Modification on the Sub-micron Particles of TiO2 Pre-coated with SiO2 and Al2O3
    LIN Yu-Lan, WANG Ting-Jie, QIN Cao, YANG Jun, JIN Yong
    2001, 22(1):  104-107. 
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    Five kinds of silane and titanate coupling, triethanolamne and pentaerythrite modification regents were used to modify the sub-micron particles of TiO2 pre-coated with SiO2 and Al2O3. The hydrophobic characteristics of samples at different modification temperatures, regent concentrations and time were investigated. Ahydrophobic index and the relative contact angle in the hydrophobic and wetting experiments were employed to evaluating modification results. The titanate coupling regent(CH3)2CHOTi(OCOOR)2OP(O)(OR')2 was found to be the best modification regent for the TiO2 particles pre-coated with SiO2 and Al2O3 from hydrophilicity to hydrophobicity. The checking results of pyrolytic gas chromatography, thermogravimetric analysis and the X-ray photoelectron spectra have shown that some modification regents were tightly coated on the particle surface. The chemical bond of Al—O—Ti is likely to form between the molecule of organic reagent (CH3)2CHOTi(OCOOR)2OP(O)(OR')2 and the particle surface in the modification process.
    A Study of Lyotropic Liquid Crystal Flooding System and Its Research at Enhanced Oil Recovery
    LI Gan-Zuo, XIAO Hong-Di, LI Ying, MU Jian-Hai, WANG Lian-Wei
    2001, 22(1):  108-111. 
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    The phase diagram of the petroleum sulfonate/pentanol/water ternary system and petroleum sulfonate/pentanol/decane/water quarternary system have been established at 25 ℃. 2H NMRspectroscopy and rheological method have been used to determine the structure which is the hexagon lyotropic liquid crystal. The results show that the areas of the liquid crystal become gradually small with the contents of decylane under a certain temperature 25 ℃. Furthermore, the lyotropic liquid crystal systems are used in place of alkaline/surfactant/polymer complicated system for ternary oil recovery. The coreflood test in the laboratory of the liquid crystal system resulted in a greater recovery of crude oil as compared to ASP(alkaline, surfactant and polymer) flooding system.
    Phase Behavior and Protein Partitioning in Aqueous Two-phase Systems Formed by Mixtures of Polymer and Cationic-anionic Surfactants
    XIAO Jin-Xin, BAO Yan-Xia, FANG Lei
    2001, 22(1):  112-114. 
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    Anovel aqueous two-phase system can be formed by the mixtures of a polymer and cationic-anionic surfactants. Such a system can be used as a partitioning system of proteins. In this work, we investigated the formation, phase behavior and protein partitioning in aqueous two-phase systems formed by dodecyltriethylammonium bromide/sodium dodecylsulfate/PEGand dodecyltriethylammonium bromide/sodium dodecylsulfate/dextran. The ligands with affinity were attached to the polymers and the affinity partitioning of proteins was investigated. It was shown that the surfactants and polymers are enriched in different phases of aqueous two-phase systems. Phase separation are promoted by increasing temperature and adding inorganic salts. Different proteins are partitioned in different phases. The selectivity of protein partitioning is increased by adding ligands with affinity.
    Studies on the Relation of Black Film Thickness and Film Tension
    HAN Guo-Bin, WU Jin-Tian, XU Xiao-Ming, WEI Guang
    2001, 22(1):  115-117. 
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    This paper covers the method of direct measurement of the disjoining pressure isotherm for sing, isolated foam films stabilized with TTABabove cmc by microinterferometric technique. It has been studied that the relation of disjoining pressure and film thickness, and the difference between the surface tension of solution and that of the common black film under different liquid film thickness conditions. The experimental results show that common black film thickness depends on the disjoining pressure and electrolytic concentration. At a low disjoining pressure, the film thickness decreases with the increase of the disjoining pressure. At a high disjoining pressure, the film thickness decreases slightly with the increase of the disjoining pressure. This signifies that the transition between black films is jumping. The electrolyte can reduce the interaction forces between two charged monolayers of film and thin the film, so the equilibrium thickness of film decreases with increasing electrolyte concentration of the solution from which they are formed. The surface tension of common black film calculated from the disjoining pressure isotherm is slightly different from the surface tension of solution.
    Monte Carlo Simulation of Diffusion of Adsorption Species on Heterogeneous Surface
    ZHANG Xiao-Gang, HAN Bu-Xing, LI Yong-Wang, ZHONG Bing, PENG Shao-Yi
    2001, 22(1):  118-121. 
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    Monte Carlo method was used to study the effect of diffusion of adsorbed hydrogen atoms on the methanol synthesis reaction behavior under a supercritical condition. The lattice model was employed to describe the surface processes, which included adsorption of reactants, surface reaction, surface diffusion of adsorbed species and re-adsorption of the product. The model converted Monte Carlo steps to the real time according to Botzzman equation. The results indicated that when the adsorbed hydrogen atoms diffused slowly, the active sites reached saturation and the turnover frequency (TOF) declined quickly. The magnitude of TOFwas not influenced by the diffusion rate of adsorbed hydrogen atoms when it reached an enough high value.
    The Conformation of N-Phenylmethylene-2-thiazoleamine Species and the Driving Forces for Twisting Molecule
    YU Zhong-Heng, XUAN Zheng-Qian, GUO Yan-Shen, PENG Xiao-Qi, WANG Tong-Xin, JIN Xiang-Lin
    2001, 22(1):  122-126. 
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    The crystal structures of N-phenylmethylene-2-thiazoleamine(2a) and N-[(4-nitrophenyl)methylene]-2-thiazoleamine (2b) were determined. Twenty-two rotational geometries(θ=0°90°) of each of two molecules were optimized using AM1, RHF/6-311G** B3LYP/6-311Gand B3LYP/6-311G** The twist angles of their preferential geometries obtained from DFTare both 0°, which are most close to the experimental values (2a, θ=8.9°; 2b, θ=3.9°) of all angles obtained from various optimized methods. Although there is a great difference in the twist angles of the five molecules, 2a, 2b, N-(4-nitrophrnyl)methylene-2-pyrimidineamine (1a), N-(4-nitrophenyl)methylene-2-pyridine-amine (1b) and N-phenyl)methylene-3-pyridineamine (1c ), their lowest total electronic energies occur in the optimized geometries with the similar twist angles which are in the region of θ from 37 to 42° and almost have nothing to do with the optimized methods (HFand DFT) and Gaussian basis sets. The π system in the geometry with θ=0° is destabilized no matter whether it is delocalized or not. It appears that the π system always prefers a twisted geometry. The driving force for out-of-plane twist of the molecules arises from the electronic interaction, and the nuclear repulsion is, practically, a resistance for distortion of molecule.
    Studies on the Reaction of OH Radical with Hexachlorobenzene
    WANG He-Feng, LI Zhao-Long, ZHU Ka-Ke, WANG Yu-Bin, HUANG Ming-Bao, WEN Zhen-Yi
    2001, 22(1):  127-129. 
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    DFTand AM1 methods were used to study the reaction of OHradical with hexachlorobenzene(HCB). The optimized structures of the reactants, the products and the transition states were found. Areasonable reaction path was determined through IRCcalculations. The activation energy obtained is in good agreement to the experimental value.
    Template Synthesis and Characterization of TiO2 Nanotubules
    LI Xiao-Hong, ZHANG Xiao-Gang, LI Hu-Lin
    2001, 22(1):  130-132. 
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    The template method for preparing nanostructures entails the synthesis of the desired material within the pores of a nanoporous membrane. In this work, TiO2 nanotubules of the anatase form have been synthesized by sol-gel chemical method using porous anodic alumina as the template. Transmission electron microscopy(TEM), scanning electron microscopy(SEM), infrared spectroscopy(IR) and X-ray diffraction were used to investigate the structure and morphology of the TiO2 nanotubules. The results showed that the diameter and length of the obtained nanotubules were determined by the pore size and length of the PAAtemplate. It was founded that through control of immersion time, both tubules and fibrils can be prepared; in addition, the wall thickness of the nanotubules can be varied at will. The result indicated that the sol particles absorbed preferably to the pore walls of the PAAmembrane due to the fact that the pore walls were negatively charged and the TiO2 particles were positively charged.
    Studies on the Surface Activity Properties of A New Type of Amphiphilic Chitosan Derivative
    SUI Wei-Ping, CHEN Guo-Hua, GAO Xian-Chi, SHANG Chun-Qing, SUN Ming-Kun
    2001, 22(1):  133-135. 
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    Anew type of amphiphilic derivative of carboxymethylchitosan(CMCHS) was prepared by reaction of CMCHSwith p-nonylphenyl glycidyl ether. The structure of the resulting derivatives, i.e., (2-hydroxyl-3-p-nonylphenoxy) propyl-carboxy-methylchitosan(HNP-CMCHS) had been identified by UVand IRspectroscopy. They are water-soluble and have surface activity, which is related to the degree of substitution and the added electrolyte in the solution. In the presence of NaCl, two transitions appeared on the surface tension-concentration plots, that means the possibility of the formation of intramolecular micelle. It was also found that it need a long time for the surface tension of the derivative solutions to get a equilibrium value and the time is related to the derivative concentration, degree of substitution and added electrolyte of the solution.
    Fluorescence of Photochromic Salicylaldehyde-Derived Schiff Bases
    ZHAO Jian-Zhang, ZHAO Bing, LIU Ju-Zheng, WANG Xu, QIU Deng-Li, SUN Li, WANG Zong-Mu, LI Yao-Xian
    2001, 22(1):  136-138. 
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    The luminescence and photochromism of a series of six salicylaldehyde-derived Schiff base in solution and solid state were investigated by fluorescence spectroscopy 2,2'-[1,2-phenylenebis(nitrilomethylidyne)]bisphenol(1); 2,2'-[1,4-phenylenebis(nitrilomethylidyne)]bis-phenol(2); 2,2'-[1,2-cyclohexanediylbis(nitrilomethylidyne)]bisphenol(3); 2,2'-[1,2-ethane diylbis(nitrilomethylidyne)]bisphenol(4); 2,2'-[1,6-hexanediylbis(nitrilomethylidyne)]bisphenol(5); 2-{[(1-phenylethyl)imino]methylidynephenol}(6). The experimental results show that the fluorescence intensity of Schiff base 1～6 is related to the structure of the conjugated system or the carbon bridge linking the two fluorophores in the molecules. The time-resolved fluorescence spectroscopy of 1, 3—6 show that they are photochromic in either solution or solid state(2 is known as a thermochromic one). The time course fluorescence spectroscopy show that the “macro-response” of Schiff bases 3, 5 and 6 with irradiation is extremely rapid, especially for 5, of which the fluorescence intensity changed by about 70% within 10 s.
    Studies on Radiation Preparation and Characteristics of κ-Carrageenan/PVP Blend Hydrogel
    ZHAI Mao-Lin, HA Hong-Fei, YOSHII Fumio, MAKUUCHI Keizo
    2001, 22(1):  139-142. 
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    In this work, a series of hydrogels in the form of rod were prepared from κ-carrageenan(KC) and poly(N-vinyl pyrrolidone)(PVP) by gamma radiation with 60Co γ source at room temperature. The properties of the prepared hydrogels, such as the gel strength, gel fraction and swelling behavior were investigated. High molecular weight PVP(k-90) blending with KCcould produces excellent hydrogels, but low molecular weight PVP(k-30) dosen't. With increasing KCcontent in the prepared hydrogel, both the gel strength and the equilibrium degree of swelling were improved. The experimental analyses showed that the crosslinking reaction of PVP(k-90) was quicker than the degradation of KCat low dose(less than 30 kGy), and the degradation of KCwas inhibited in PVP/KCmixture system. An interpenetrating polymer network(IPN) hydrogel composed of PVP(a chemically crosslinked network) and KC (a physically crosslinked network) was proposed. In addition, the dose influenced greatly the preparation of the hydrogel.
    A Molecular Device Controlled by Acid-Base——A New Switch of the Pseudorotaxane Based on Electron Donor Biphenyl Ether Derivatives and Electron Accepter CPQT
    WANG Le-Yong, XI Hai-Tao, SUN Xiao-Qiang, PAN Yi, HU Hong-Wen
    2001, 22(1):  143-145. 
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    Anew type pseudorotaxanes are formed in solution by self-assembly of wire-type electron donor 4,4'-oxydianiline(A) and electron accepter cyclo bis(paraquat-phenylene)tetracationic cyclophane(CPQT) which can be unthreaded and rethreaded by acid-base. The threading/unthreading processes are accompanied and therefore can be monitored by strong changes in 1H NMRchemical shift data of system.
    Preparation of Mosaic Latex Particles
    LI Xiao-Yu, SHI Shu-Xian, KOU Yi, DONG Han-Peng, XIA Yu-Zheng
    2001, 22(1):  146-150. 
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    Anew kind of mosaic latex particles with gradient distribution of hard polymer have been synthesized through two-stage emulsion polymerization based on natural rubber latex. One or two or three of styrene, methyl methacrylate, acrylonitrile, isobornyl acrylate were used as hard monomer in order to prepare interpenetrating polymer network. When oleinic acid was selected as emulsifier, t-butylhydroperoxide-tetraethylene pentamine as oxi-reduction initiation system, the polymerization proceeded for 6 h in natural rubber latex smoothly with the 99% conversion of monomer. The effects of emulsifiers and the initiators on the polymerization were studied; the effects of crosslinker, swelling degree, hard monomer on morphology of the title latex particles were also investigated. The result of morphology analysis of the latex showed that the latex particle was mosaic structure with hard polymer gradient distributed.
    Effect of Substrate on the Phase Inversion of PMMA/PS Blend Films
    FANG Jian, KONG Xiang-Ming, GUO Bao-Hua, HU Ping, XIE Xu-Ming
    2001, 22(1):  151-153. 
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    The effect of substrate on the phase morphologies of PMMA/PSblend films was investigated by means of phase contrast microscope. PMMA/PSblend films were cast onto various substrates(such as glass substrate and PPsubstrate) by spin-coating with thickness of about 10 μm. It was observed that there was a large difference of the phase inversion region between the blend films cast on glass and on PPsubstrates. On glass substrate, the phase inversion occurred at about Φm=04(PSmass fraction) while at Φm=05 on PPsubstrate. This implies that there is a shift of the phase inversion region with the change of substrate in cast polymer blend films. In other words, phase inversion region depends on the substrate. ATR-FTIRanalysis was used to detect the composition of the surface and the bottom of the films(about 100 μm thick) obtained by evaporating solvent from the polymer blend solution. The ATR-FTIRspectra of the surface and the bottom of the PMMA/PSblend thin films cast on glass substrate and PPsubstrate showed that PMMAcomponent preferentially segregated to glass substrate and PScomponent was enriched on the PPsubstrate. This selective segregation was due to the difference of the wetting abilities of PSand PMMAon the two kinds of substrates. The polymer-substrate interfacial tension γ were calculated and the results supported the ATR-FTIRresults. It could be inferred that the shift of the phase inversion region with the change of the substrate in PMMA/PSblend film was due to the fact that the composition of the blend in the bulk changed, owing to the selective enrichment of one component of polymer blend to the substrate. In other words, the affinity between polymer and substrate can strongly influence the phase morphologies and the phase inversion region in polymer blend films.
    Lanthanum Stearate Composite Act as β-Modification Nucleating Agent of Isotatic Polypropylene
    FENG Jia-Chun, CHEN Ming-Cai, HUANG Zhi-Tang
    2001, 22(1):  154-156. 
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    Acomposite of 60% of lanthanum stearate and 40%(mass fraction) of stearic acid was prepared and its influence on the crystallization characteristics of isotatic polypropylene (iPP) was investigated. The results showed that we had found a new kind of β-crystalline form nucleating agent. The composite might induced rather high proportion of β-modification. The relative content of β-phase estimated by WAXDand DSCwas 30% and 51.8% in a PPcontaining 2.5%(mass fraction) of the composite respectively. The isothermal crystallization at 130 ℃ and melting behavior examined by DSCrevealed that the composite accelerated the overall rate of crystallization remarkably. The half crystallization period t 1/2 decreased from 118 min of pure PPto 75 min of PPcontaining 2.5% of the composite. However, the composite had no obvious influence on crystallization mode and the size of α-crystal unit cell.
    Synthesis of Poly(methyl methacrylate)-block-polytetrahydrofuran by Coupling of Cationic and Anionic Living Chains
    WANG Guo-Jian, YAN De-Yue, AxelH. E. Müller
    2001, 22(1):  157-159. 
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    The diblock copolymer poly(methyl methacrylate)-block-polytetrahydrofuran(PMMA-b-PTHF) was successfully synthesized by means of the coupling reaction of living cationic PTHF+, SbF-6 and living anionic PMMA-, Li+. Lithium chloride, which is frequently used as a ligand in the polymerization of (meth)acrylates, obstructs the coupling reaction between the anionic and the cationic precursors due to the combination of the chlorine anion with the PTHFcation. Thus, the anionic polymerization should be carried out in the absence of LiCl.
    Studies on Polymerization of Norbornene with Titanocene/MAO Catalyst System
    LU Ying-Ying, WU Qing, LU Ze-Jian
    2001, 22(1):  160-162. 
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    Vinyl-type polymerization of norbornene has been carried out with half-titanocene/MAOcatalysts. It was found that the Cp(cyclopentadienyl)-bearing titanocene catalysts afford the polynorbornene at much higher yield than the related Cp*(pentamethylcyclopentadienyl)-bearing one. On the other hand, substitution of —ORligand for chlorine at the Cp-bearing compound causes remarkbaly increase in catalytic activity. The optimum temperature for the polymerization is 60 ℃. All the polynorbornenes obtained with CpTi(OCH2Ph)3/MAOcatalyst are soluble in the organic solvents such as cyclohexane and monochlorobenzene. The FTIRand 13C NMRspectra indicate that the polynorbornene obtained is vinyl-type polymer and has low stereo-regularity.
    PTC Effect in HDPE/EPDM/CB Composites
    HE Xiu-Juan, WANG Li-Jie, LIU Zhi-Cheng, CHEN Xin-Fang
    2001, 22(1):  163-165. 
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    Polymer positive temperature coefficient(PTC) material comprising conductive particles, e.g. carbon black(CB), dispersed in polymer matrix is suitable for use as electrical devices such as circuit overcurrent protection device, self-regulation heaters, sensors, etc.. In this paper, the PTCeffect of carbon black filled polyethylene and ethylene-propylene-diene terpolymer blends was studied. Effects of raw material ratio and type of carbon black were investigated. The distribution of CBin polymer matrix and the function of crystallites on PTCeffect were discussed.
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