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25 September 2008, Volume 24 Issue 5

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Content of Chemical Research in Chinese Universities Vol.24 No.5(2008)

2008, 24(5):  0-0.  doi:

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Articles

Comparison of the Sol-gel Method with the Coprecipitation Technique for Preparation of Hexagonal Barium Ferrite

WANG Jing-ping , LIU Ying , ZHANG Mi-lin , QIAO Ying-jie , XIA Tian

2008, 24(5):  525-528.  doi:

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Hexagonal barium ferrite BaFe₁₂O₁₉ particles were prepared by sol-gel and coprecipitation methods, respectively. The composition of the so-obtained materials was investigated by means of XRD. By the sol-gel method, non-anticipated intermediate crystalline phases, such as γ-Fe₂O₃, α-Fe₂O₃, BaCO₃, and BaFe₂O₄ etc., were formed with the delay of the formation of BaFe₁₂O₁₉. The formation of single phase BaFe₁₂O₁₉ required calcination at 850 oC for 4 h. On the other hand, using coprecipitation technique, amorphous hydroxide precursor was directly transferred into BaFe₁₂O₁₉ almost without the formation of intermediate crystalline phases. BaFe₁₂O₁₉ was prepared by calcining at 700 oC for 3 h. The results were confirmed by ESEM and VSM analyses. Based on the already reported results and the observed results in this study, it can be concluded that the coprecipitaion technique is easier to control than the sol-gel method for preparation of BaFe₁₂O₁₉ at a low temperature.

Hydrothermal Synthesis, Crystal Structure and Spectroscopic Investigations of [Y(C6NO2H5)3(H₂O)₂]_n(1.5nZnCl₄)·nH₂O with Unprecedented Polycationic Chains

FANG Xiao-niu , CHEN Wen-tong , LIU Dong-sheng

2008, 24(5):  529-533.  doi:

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A new heterometallic 4f-3d complex [Y(C₆NO₂H₅)₃(H₂O)₂]_n(1.5nZnCl₄)·nH₂O(1), was synthesized via a hydrothermal reaction and structurally characterized. Complex 1 crystallized in the monoclinic system with space group P2₁/c: a=0.94847(9) nm, b=2.0947(2) nm, c=1.6001(2) nm, β=104.467(2)°, V=3.0781(5) nm³, M_r=823.04, D_c=1.776 g/cm³, S=1.009, μ(Mo Kα)=3.603 mm^–1, F(000)=1632, R=0.0787, and wR=0.2273. Complex 1, with four formula units in a cell, was characteristic of a one-dimensional polycationic chain-like structure. Photoluminescent investigation showed that the title complex displayed a strong emission in the blue region, which was attributed to the intraligand π-π^* transition of the nicotinic ligands. Optical absorption spectrum of complex 1 revealed the presence of a wide optical bandgap of 4.17 eV.

Synthesis and Soft Magnetic Properties of Mg-doped Ni Nanoparticles

YANG Jing-hai , FENG Bo , LIU Yang , ZHANG Yong-jun , YANG Li-li, , WANG Ya-xin , LANG Ji-hui , WANG Dan-dan

2008, 24(5):  534-536.  doi:

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Mg-doped Ni nanoparticles with good soft magnetic properties were prepared with the sol-gel method and were sintered at 400, 500, 600, and 900 °C in argon atmosphere, respectively. The structure and magnetic properties of the samples were studied by means of X-ray diffraction, TEM, and VSM magnetometers. X-Ray powder diffraction results show that Ni-Mg solid solution was formed with the single phase of face-centered cubic(fcc) structure. The particle size became larger with the increase of temperature. When the sintering temperature was 400 °C, the particle size was 6.3 nm, whereas it was 46.2 nm at 900 °C. Both the saturation magnetization(M_s) and the coercivity were enhanced with the increase of the particle size. The M_s values of the samples ranged from 18.965 to 46.766 emu/g and the coercivity ranged from 1051.3568 to 9145.0848 A/m.

Gold Nanoparticle-based Colorimetric Sensor for pH Sensing

ZHU Lin , XUE Dong-hua , WANG Zhen-xin

2008, 24(5):  537-540.  doi:

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We present a newly designed colorimetric sensor sensitive to pH value based on a gold nanocomposite composed of gold nanoparticles and pH-sensitive polymer{dodecylthioether end functionalized poly[2-(diethylamino) ethyl methacrylate], poly(DEAEMA)-DDT}. We have shown that this design can produce stable GNP precipitate under weakly basic condition(pH=7.5) and this precipitate can be dispersed in acidic solution(pH=4.0), due to the 2-(diethylamino) ethyl methacrylate protonated by H⁺. The precipitation-dispersion process is reversible and accompanied by distinct color change that are clearly visible to the naked eye. This development may have application in the controlled fabrication of reversible pH-sensitive nanostructures and/or devices.

QSAR Studies on PCDD/Fs by Kernel PLS

TANG Kai-lin, LI Tong-hua , CHEN Kai

2008, 24(5):  541-545.  doi:

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QSPR models of PCDD/Fs were generated by means of kernel partial least squares. The molecular distance-edge vector method was used as descriptors to get model I for predicting PCDD/Fs retention behavior. The chlorinated positions were also used and model II was obtained. In studied cases, the predictive ability of the KPLS model is comparable or superior to those of PLS and ANN. The results indicate that KPLS can be used as an alternative powerful modeling tool for QSPR studies.

Iodine Determination by Microwave Plasma Torch Atomic Emission Spectrometer Coupled with Online Preconcentration Vapor Generation Technique

FEI Yan-qun , LUO Gui-min , FENG Guo-dong , CHEN Huan-wen , FEI Qiang , HUAN Yan-fu , JIN Qin-han

2008, 24(5):  546-549.  doi:

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This article focuses on iodine determination by microwave plasma torch atomic emission spectrometry (MPT-AES) coupled with online preconcentration vapor generation method. A new desolvation device, multistrand Nafion dryer, was used as the substitute for condenser desolvation system. Some experimental conditions, such as preconcentration time, acidity of sample solution, rinsing solution acidity and dynamic linear range were investigated and optimized. The new desolvation system eliminates the problem of decreasing emission intensity of I(I) 206.238 nm line with the increase of working time on a conventional condenser desolvation system, thus greatly improving the reproducibility.

Subunit Characteristics of Pig Pancreas Ferritin Revealed by MALDI-TOF MS and RP-HPLC

HUANG Lin, , LIN Zhi-cao , LIN Qing, , LUO Lian-zhong, , HUANG He-qing,

2008, 24(5):  550-556.  doi:

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Pig pancreas ferritin(PPF) was purified by ultra-centrifugation, ion-exchange chromatography, and native gradient polyacrylamide gel electrophoresis(PAGE_NG). Sodium dodecyl sulfate(SDS)-PAGE indicates that PPF consists of two subunit types, namely, H(21000) and L(19000) subunits, and its core shows an average element composition of 1698 Fe³⁺ and 179 phosphate molecules within the hollow shell, giving a 9.5:1 ratio of Fe³⁺ to phosphate. An off line approach combining reversed-phase high-performance liquid chromatography(RP-HPLC) with matrix-assisted laser desorption ionization time of flight mass spectrometry(MALDI-TOF MS) made the decomposition of PPF shell into H and L subunits for the analysis of mass spectrometry(MS), giving molecular weights of both H(21014.4) and L(18319.9) subunits. Both subunit types were further identified by an approach combining peptide mass fingerprint(PMF) with database search. A ratio of 1H to 2L subunits in PPF was determined by SDS-PAGE, RP-HPLC, and MALDI-TOF MS, respectively. It is well known that the non-covalent interaction of L-L or H-L subunits is stronger than that of H-H subunits in PPF, which may be further used to explain the unclear physiological function between H and L subunits in PPF.

Selective Reduction of 7-Demethylsinomenine

LI Yu-feng , BU Qing-min , QIAN Yi , PAN Yi , LI Jian-xin , HUANG Le-qun , ZHU Hong-jun

2008, 24(5):  557-560.  doi:

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Several borohydride reagents: sodium borohydride, sodium cyanoborohydride, soudium acetoxyborohydride and soudium triacetoxyborohydride were screened, respectively, for the reduction of 7-demethylsinomenine, which was an α,β-dicarbonyl compound derived from sinomenine. Highly regio- and stereo-selectivity was acquired when sodium cyanoborohydride or NaBH(OAc)₃ was used. The product was structurally confirmed as 7R configuration by NMR, X-ray crystal diffraction analysis. Some preliminary discussion was also made on the mechanism of the selective reduction.

Syntheses and Structures of Binaphthyl-bridged Schiff Bases

WANG Bin, LI Min-xiong, XU Shan-sheng, SONG Hai-bin , WANG Bai-quan

2008, 24(5):  561-564.  doi:

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The reaction of dinaphthofuran with lithium in anhydrous diethyl ether led to a solution of the corresponding C,O-dilithiated intermediate which, upon treatment with DMF at −78 oC, afforded, after hydrolysis, 2’-hydroxy-1,1’- binaphthyl-2-carbaldehyde in a good yield. Then binaphthyl-bridged Schiff bases were prepared by the condensation of 2’-hydroxy-1,1’-binaphthyl-2-carbaldehyde with the corresponding aromatic amines.

Isolation of Trichoderma reesei pyrG Negative Mutant by UV Mutagenesis and Its Application in Transformation


LONG Hao, WANG Tian-hong , ZHANG Ying-kuan

2008, 24(5):  565-569.  doi:

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Two uridine auxotrophic mutants of Trichoderma reesei were isolated by resistance to 5-fluoroorotic acid after UV mutagenesis. One mutant, called M23, was complemented with the Aspergillus niger pyrG gene carried by plasmid pAB4-1. A mutated pyrG gene of M23 was cloned and DNA sequencing analysis indicated that a cytosine was inserted into the 934―939 oligo dC position of the pyrG coding region, resulted in a frameshift mutation. Transformation efficiency was approximately 200―300 transformants per microgram of DNA with plasmid pAB4-1. Stable transformants were obtained by monosporic culture and showed to be prototroph after successive propagation. Vitreoscilla hemoglobin expression plasmid pUCVHb was cotransformed with plasmid pAB4-1 and attained a transformation efficiency of 71.8% or of 26.1% with pAN7-1. Southern blot analysis of the transformants demonstrated that plasmid pUCVHb was integrated into the chromosomal DNA. The experimental results demonstrated that the pyrG-based system was more efficient and timesaving than the conventional hygromycin B resistance-based transformation system.

Synthesis and Luminescent Property of Polycarbazole/Polyhedral Oligomeric Silsesquioxane Nanocomposites

ZHU Yu-fang , ZHAO Jun-feng , WANG Xi , LI Qi-fang

2008, 24(5):  570-574.  doi:

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Polyvinylcarbazole(PVK) composites containing organic-inorganic hybrid polyhedral oligomeric silse- squioxane(POSS) PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole and were completely dispersed at molecular level in PVK matrix and PVK-POSS nanocomposites display higher glass transition temperature(T_g) in comparison with neat PVK. Optical properties of PVK/POSS nanocomposites were investigated by UV-spectrum and PL-spectrum and the results show that the PVK-POSS nanoparticles have a good interface effect and improve color purity effectively. The maximum absorption wavelength bathochromically shifts gradually with the increasing of the content of POSS. The luminescent intensity becomes higher and higher with the increase of POSS content, and reaches its maximum luminescent intensity when the POSS content is 3% (mass fraction), while some POSS-rich nanoparticles are present in matrix when contents of POSS are beyond 5%.

Synthesis, Characterization and Biological Activities of Novel Acrylamide Compounds

XU Liang-zhong , XU Zhong-jie, ZHANG Gong-sheng, ZHOU Kai , ZHAI Zhi-wei

2008, 24(5):  575-578.  doi:

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With dimethomorph and flumorph as the leading compounds, four novel acrylamide compounds with two types of structure were designed and synthesized by means of the method of “me too chemistry”. The target compounds were characterized by ¹H NMR, IR, MS, and elemental analysis. The influences of solvent and raw material on the yield were investigated and optimum processing conditions were determined. The results of preliminary biological tests show that all those compounds exhibit certain antifungal activities.

Construction of HIV-1 Virus-like Particle Vaccine

ZHAO Dong-hai , ZHANG Xi-zhen , YU Xiang-hui , KONG Wei

2008, 24(5):  579-583.  doi:

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The virus-like particle(VLPs) vaccine is an ideal HIV-1 vaccine, which can simultaneously induce a neutralizing antibody reaction and cell-mediated immunity effectively. In this study, two kinds of plasmids have been used, one can express the HIV-1 main structure proteins, Gagpol and Env, and the other contains an antibiotic gene. The two kinds of plasmids have been cotransfected into 293 cells. A stable cell line that can express Gagpol and Env proteins efficiently and lastingly has been screened. It has been confirmed that Gagpol and Env proteins in the cell culture supernatant can be self-assembled into virus-like particles. The authors have detected the secretion of VLPs in the cell medium, defined the peak of the secretion, and followed and monitored the stability of expression.

Isolation and Purification of Polysaccharides from Cordyceps minlitaris and Its Inhibition on the Proliferation of Rat Glomerular Mesangial Cells

HOU A-li, MENG Qing-fan, AN Jin-shuang, ZHU Kai, FENG Yun , TENG Li-rong

2008, 24(5):  584-587.  doi:

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The crude polysaccharide was obtained by means of the decolorization of porphyrized Cordyceps minlitaris stroma with organic solvent, extraction with hot water, precipitation in 80% ethanol, and protein removal with the Sevag method. After purification with Sephadex G-75, two of its components, CMP-1 and CMP-2, were obtained. Through the assay of gel chromatography and polarimetry, CMP-1 was identified as pure polysaccharide. The results demonstrated that CMP-1 had favorable oxidation resistance activity, which could scavenge not only oxygen-free radicals in the self-oxidation system of pyrogallic acid, but also the hydroxide-free radicals in the Fenton system. The study focused on the effects of low, medium, and high dosages of CMP-1 in rat blood serum on the proliferation of glomerular mesangial cells in vitro. Through MTT Colorimetric analysis, the activities were compared among the blank control group and the Niaoduqing positive control group CMP-1 and CMP-2. The results shows that CMP-1 was able to inhibit the proliferation of rat glomerular mesangial cells effectively. Therefore, CMP-1, one component of polysaccharides of Cordyceps minlitaris, was certainly a potential remedy for hyperplastic glomerular nephritis, whose antioxidant activity could slow down the process of chronic renal failure(CRF) to some extent.

Preparation and Characterization of Biodegradable Polylactide(PLA) Microspheres Encapsulating Ginsenoside Rg3

LIU Cheng-bai, ZHANG Di, LI De-guan, JIANG Dan , CHEN Xia

2008, 24(5):  588-591.  doi:

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In this study, the process of a biodegradable polylactide(PLA) microsphere encapsulating ginsenoside Rg3 was first studied by the emulsion solvent evaporation method, for enhancing solubility and stability of ginsenoside Rg3. Alabum was also first used as a modifier in this method. The mean diameter of the prepared PLA microspheres containing Rg3 was 40 µm. Ginsenoside Rg3 released from the microspheres was studied by HPLC and detected by UV. It was found that the drug release curve fitted the Model Heller-Baker best.

Purification and Characterization of the Catalytic Domain of Protein Tyrosine Phosphatase SHP-1 and the Preparation of Anti-ΔSHP-1 Antibodies

LI Wan-nan , ZHUANG Yan , LI He , SUN Ying , FU Yao , WU Xiao-xia , ZHAO Zhi-zhuang, , FU Xue-qi

2008, 24(5):  592-596.  doi:

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This study is focused on the expression of an SH2 domain-truncated form of protein tyrosine phosphatase SHP-1(designated ΔSHP-1) and the preparation of its polyclonal antibodies. A cDNA fragment encoding ΔSHP-1 was amplified by PCR and then cloned into the pT7 expression vector. The recombinant pT7-ΔSHP-1 plasmid was used to transform Rosetta(DE3) E. coli cells. ΔSHP-1 was distributed in the exclusion body of E. coli cell extracts and was purified through a two-column chromatographic procedure. The purified enzyme exhibited an expected molecular weight on SDS-gels and HPLC gel filtration columns. It possesses robust tyrosine phosphatase activity and shows typical enzymatic characteristics of classic tyrosine phosphatases. To generate polyclonal anti-ΔSHP-1 antibodies, purified recombinant ΔSHP-1 was used to immunize a rabbit. The resultant anti-serum was subjected to purification on ΔSHP-1 antigen affinity chromatography. The purified polyclonal antibody displayed a high sensitivity and specificity toward ΔSHP-1. This study thus provides the essential materials for further investigating the biological function and pathological implication of SHP-1 and screening the inhibitors and activators of the enzyme for therapeutic drug development.

Etoposide Induces Mitochondria-Associated Apoptotic Cell Death in Human Gastric Carcinoma Cells

LI Jing-hua , CHEN Yue , WANG Jia-si , KONG Wei , JIN Ying-hua

2008, 24(5):  597-602.  doi:

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Recent observations indicate that the resistance of apoptosis is an important process of tumor metastasis and metastases are the cause of 90% of human cancer death. Etoposide, a semisynthetic derivative of the podophyllotoxins, is a clinically used anti-cancer reagent, but the effects of it on metastatic gastric carcinoma cells are totally unknown. In this study, etoposide induced apoptotic cell death in human gastric adenocarcinoma cell line SGC-7901, derived from metastatic lymph nodes, as evidenced by the analysis of DNA fragmentation, apoptotic body formation, caspase activation, and apoptosis specific changes in cell morphology is demonstrated. The depolarization of mitochondrial membrane and the release of cytochrome c were most early events in etoposide treated SGC-7901 cells, and were followed by caspase-3 activation and PARP cleavage. Caspase-8 activation was not detected under the same condition. Thus, it was proposed that etoposide induces caspase-associated apoptotic cell death in human metastatic gastric carcinoma, which is initiated by mitochondrial cytochrome c release.

Low Temperature Heat Capacities and Thermodynamic Properties of Zinc L-Threonate Zn(C₄H₇O₅)₂(s) by Adiabatic Calorimetry

CHEN Jing-tao , DI You-ying , TAN Zhi-cheng , CHEN San-ping , GAO Sheng-li

2008, 24(5):  603-607.  doi:

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Low-temperature heat capacities of the solid compound Zn(C₄H₇O₅)₂(s) were measured in a temperature range from 78 to 374 K, with an automated adiabatic calorimeter. A solid-to-solid phase transition occurred in the temperature range of 295—322 K. The peak temperature, the enthalpy, and entropy of the phase transition were determined to be (316.269±1.039) K, (11.194±0.335) kJ·mol^-1, and (35.391±0.654) J·K^-1·mol^-1, respectively. The experimental values of the molar heat capacities in the temperature regions of 78—295 K and 322—374 K were fitted to two polynomial equations of heat capacities(C_p,m) with reduced temperatures(X) and [X=f(T)], with the help of the least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound, relative to that of the standard reference temperature 293.15 K, were calculated on the basis of the fitted polynomials and tabulated with an interval of 5 K. In addition, the possible mechanism of thermal decomposition of the compound was inferred by the result of TG-DTG analysis.

Thermal Behavior, Nonisothermal Decomposition Reaction Kinetics of Mixed Ester Double-base Gun Propellants

YI Jian-hua, ZHAO Feng-qi , XU Si-yu, GAO Hong-xu , HU Rong-zu

2008, 24(5):  608-614.  doi:

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The thermal decomposition behavior and nonisothermal reaction kinetics of the double-base gun propellants containing the mixed ester of triethyleneglycol dinitrate(TEGDN) and nitroglycerin(NG) were investigated by thermogravimetry(TG) and differential thermogravimetry(DTG), and differential scanning calorimetry(DSC) under the high-pressure dynamic ambience. The results show that the thermal decomposition processes of the mixed nitric ester gun propellants have two mass-loss stages. Nitric ester evaporates and decomposes in the first stage, and nitrocellulose and centralite II(C₂) decompose in the second stage. The mass loss, the DTG peak points, and the terminated temperatures of the two stages are changeable with the difference of the mass ratio of TEGDN to NG. There is only one obvious exothermic peak in the DSC curves under the different pressures. With the increase in the furnace pressure, the peak temperature decreases, and the decomposition heat increases. With the increase in the content of TEGDN, the decomposition heat decreases at 0.1 MPa and rises at high pressure. The variety of mass ratio of TEGDN to NG makes few effect on the exothermic peak temperatures in the DSC curves at different pressures. The kinetic equation of the main exothermal decomposition reaction of the gun propellant TG0601 was determined as: dα/dt=10^21.59(1–α)³e^{–2.60×104/T}. The reaction mechanism of the process can be classified as chemical reaction. The critical temperatures of the thermal explosion(T_be and T_bp) obtained from the onset temperature(T_e) and the peak temperature(T_p) are 456.46 and 473.40 K, respectively. ΔS^≠, ΔH^≠, and ΔG^≠ of the decomposition reaction are 163.57 J·mol^–1·K^–1, 209.54 kJ·mol^–1, and 133.55 kJ·mol^–1, respectively.

TiO₂-Supported Binary Metal Oxide Catalysts for Low-temperature Selective Catalytic Reduction of NO_x with NH₃


WU Bi-jun , LIU Xiao-qin , XIAO Ping , WANG Shu-gang

2008, 24(5):  615-619.  doi:

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Binary metal oxide(MnO_x-A/TiO₂) catalysts were prepared by adding the second metal to manganese oxides supported on titanium dioxide(TiO₂) , where, A indicates Fe₂O₃, WO₃, MoO3, and Cr₂O₃. Their catalytic activity, N₂ selectivity, and SO₂ poisonous tolerance were investigated. The catalytic performance at low temperatures decreased in the following order: Mn-W/TiO₂＞Mn-Fe/TiO₂＞Mn-Cr/TiO₂＞Mn-Mo/TiO₂, whereas the N₂ selectivity decreased in the order: Mn-Fe/TiO₂＞Mn-W/TiO₂＞Mn-Mo/TiO₂＞Mn-Cr/TiO₂. In the presence of 0.01% SO₂ and 6% H₂O, the NO_x conversions in the presence of Mn-W/TiO₂, Mn-Fe/TiO₂, or Mn-Mo/TiO₂ maintain 98.5%, 95.8% and 94.2%, respectively, after 8 h at 120 °C at GHSV 12600 h^-1. As effective promoters, WO₃ and Fe₂O₃ can increase N₂ selectivity and the resistance to SO₂ of MnO_x/TiO₂ significantly. The Fourier transform infrared(FTIR) spectra of NH₃ over WO₃ show the presence of Lewis acid sites. The results suggest that WO₃ is the best promoter of MnO_x/TiO₂, and Mn-W/TiO₂ is one of the most active catalysts for the low temperature selective catalytic reduction of NO with NH₃.

Catalytic Oxidation of NO over La_0.8Sr_0.2MnO₃ Perovskite

ZHAO Ying-xian , WEI Feng , YU Ying

2008, 24(5):  620-627.  doi:

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Catalytic oxidation of NO by O₂ over La_0.8Sr_0.2MnO₃ was tested in a tubular reactor. The reaction temperature ranged from 373 to 473 K, space time from 0.090 to 0.720 s, inlet NO concentration from 300 to 2000 μL/L, and O₂ volume fraction from 3% to 9%. The steady-state conversion of NO was increased significantly with increasing reaction temperature and the space time, slightly with increasing the O₂ concentration but decreased with increasing the inlet NO concentration at a lower temperature. Under the conditions of 0.720 s space time, 500 μL/L NO concentration, 5% O₂ volume fraction and 473 K, NO conversion reached 90%. A kinetic model including a network of 12 elementary reactions with the desorption of NO₂ as the rate-limiting step is established and fits the experimental data well. The activation energy of NO₂ desorption from the catalyst surface is determined to be 101 kJ/mol.

Thermal Degradation Kinetics of N,N’- Di(diethoxythiophosphoryl)-1,4-phenylenediamine

REN Yuan-lin , CHENG Bo-wen , ZHANG Jin-shu , JIANG Ai-bing , FU Wen-li

2008, 24(5):  628-631.  doi:

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The non-isothermal degradation kinetics of N,N’-di(diethoxythiophosphoryl)-1,4-phenylenediamine in N₂ was studied by TG-DTG techniques. The kinetic parameters, including the activation energy and pre-exponential factor of the degradation process for the title compound were calculated by means of the Kissinger and Flynn-Wall- Ozawa(FWO) method and the thermal degradation mechanism of the title compound was also studied with the Satava-Sestak methods. The results indicate that the activation energy and pre-exponential factor are 152.61 kJ/mol and 9.06×10¹⁴ s^-1 with the Kissinger method and 154.08 kJ/mol with the Flynn-Wall-Ozawa method, respectively. It has been shown that the degradation of the title compound follows a kinetic model of one-dimensional diffusion or parabolic law, the kinetic function is G(α)=α² and the reaction order is n=2.

Effects of Lanthanide Ions on Electrooxidation of Methanol

WANG Hai-tao , YIN Yu-chun , GAO Shu-juan

2008, 24(5):  632-634.  doi:

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Four kinds of lanthanide ions(Sm³⁺, Yb³⁺, Eu³⁺, La³⁺）as an additive were added into the aqueous solution containing methanol, respectively, and their effects on methanol elecotrooxidation in aqueous solutions were studied with cyclic voltammetry. The results show that the four kinds of ions have promotion action upon the electrooxidation of methanol to different degrees. The best additive, Sm³⁺, can increase the anodic oxidation current of methanol by 80% and the peak potential shifted negatively about 50 mV. The promotion effects of the lanthanide ions were considered to be related to the extranuclear electron distribution of these ions and their adsorption on the Pt electrode surface.

Electroless Nickel Plating and Electroplating on FBG Temperature Sensor

SHEN Ren-sheng , TENG Rui , LI Xiang-ping , ZHANG Jin , XIA Dao-cheng , FAN Zhao-qi , YU Yong-sen , ZHANG Yu-shu , DU Guo-tong

2008, 24(5):  635-639.  doi:

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Metal-coated fiber Bragg grating(FBG) temperature sensors were prepared via electroless nickel(EN) plating and tin electroplating methods on the surface of normal bare FBG. The surface morphologies of the metal-coated layers were observed under a metallographic microscope. The effects of pretreatment sequence, pH value of EN plating solution and current density of electroplating on the performance of the metal-coated layers were analyzed. Meanwhile, the Bragg wavelength shift induced by temperature was monitored by an optical spectrum analyzer. Sensitivity of the metal-coated FBG(MFBG) sensor was almost two times that of normal bare FBG sensor. The measuring temperature of the MFBG sensor could be up to 280 °C, which was much better than that of conventional FBG sensor.

Blends of Polypropylene and Syndiotactic 1,2-Polybutadiene: Morphology, Crystallization Behaviors and Mechanical Properties

ZHANG Cheng-wu , HUANG Yu-dong , WANG Sheng-chao , ZHANG Chun-yu , ZHANG Xue-quan

2008, 24(5):  640-643.  doi:

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Morphologies, crystallization behavior and mechanical properties of polypropylene(PP)/syndiotactic 1,2-polybutadiene(s-1,2 PB) blends were investigated. Morphology observation shows the well dispersed domains of s-1,2 PB in PP matrix with the rather small domain sizes from 0.1 to 0.5 µm when the s-1,2 PB content increases from 5% to 20% (mass fraction) in the blends, and the phase structure tends to become co-continuous as s-1,2 PB content further increases. Crystallization temperature(T_c) of PP component in the blends is fluctuated with the variation of s-1,2 PB content in the blends. Compatibilization, to some extent, between the two components is inferred from the examination of both morphology and crystallization behavior. Improvement of impact strength of PP toughened by s-1,2 PB becomes significant only in the case of s-1,2 PB content above 20%(mass fraction).

Influence of Glycerol Content on Properties of Wheat Gluten/Hydroxyethyl Cellulose Biocomposites


SONG Yi-hu , ZHENG Qiang , LIU Cheng

2008, 24(5):  644-647.  doi:

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Environmentally friendly biocomposites were prepared by blending wheat gluten(WG) as a matrix, hydroxyethyl cellulose(HEC) as a filler, and glycerol as a plasticizer, followed by thermo-molding of the mixture at 120 °C for crosslinking the matrix. Moisture absorption, tensile properties, dynamic mechanical analysis, and dynamic rheology were evaluated in relation to the glycerol content. Tensile strength and modulus drop dramatically with increasing glycerol content, which is accompanied by significant depression in the glass transition temperature and improvement in the extensibility of the biocomposites.

PTC/NTC Behavior of PVDF Composites Filled with GF and CF

WANG Xin-lei, ZHANG Guo , LI Ji-xin, LI Zhuo-shi, LIU Zhan-fang , LIU Xiu-qi

2008, 24(5):  648-652.  doi:

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Conductive polyvinylidene fluoride(PVDF) matrix composites filled with graphited fiber(GF) or carbon fiber(CF) were prepared by the melt-mixing method. The breakage and length distribution of the fibers in the polymer matrix were studied by scanning electron microscope(SEM) and optical microscope(OM) observations, respectively. The differences in the positive temperature coefficient(PTC) effects of the composites were mainly attributed to inter-fiber contact ability. The elimination of the negative temperature coefficient(NTC) effect for CF/PVDF composite was because of an increase in the viscosity of the polymer matrix. With the same filler content, CF could be more effective, to eliminate the NTC effect when compared with GF. Addition of 2% CF(mass fraction) in the PVDF composite with 7% GF(mass fraction) could effectively eliminate the NTC phenomenon of the composite.

Effect of Ultrasonication on Optical Properties and Electronic States of Conjugated Polymer MEH-PPV

WU Meng, YANG Gui-zhong, WANG Meng, WANG Wei-zhi, WANG Min , LIU Tian-xi

2008, 24(5):  653-657.  doi:

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Poly[2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene](MEH-PPV) solutions with different concen- trations were prepared in chloroform for different ultrasonication times. The ultraviolet absorption and photoluminescence(PL) spectra of the MEH-PPV solutions were measured, and the electronic states of the polymer chains under different experimental conditions were studied. The results showed that the effects of ultrasonication on the dilute and concentrated solutions were different. After ultrasonication, the intensity of the absorption peak at 280 nm significantly decreased, relative to the absorption peak at 500 nm for both dilute and concentrated solutions, indicating that the proportion of the two excited states in the polymer chains had changed. For dilute MEH-PPV solutions, the blue-shifted absorption(at about 500 nm) and PL spectra show that ultrasonication also led to polymer chain degradation and thus shortened the effective conjugation length. For concentrated solutions, however, the peak positions of the absorption spectra remained unchanged. In addition, the effects of the solution temperatures on the optical spectra for the MEH-PPV solutions were also discussed.

Research Note

Reduction of Aldehydes by Fe-H₂O-CO₂ System in Supercritical Carbon Dioxide

HUANG Xi-zhe , JIANG Huan-feng

2008, 24(5):  658-660.  doi:

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Fe-H₂O-CO₂ was first reported as a good reducing reagent for the reduction of aldehydes in supercritical carbon dioxide (scCO₂). The corresponding aromatic alcohols were obtained in moderate to good GC yields (76–100%) and high chemoselectivity. Aliphatic aldehydes were also reduced to corresponding alcohols. The results showed that carbon dioxide plays an important role as both solvent and reagent.