15 April 2012, Volume 43 Issue 07
    

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    研究与开发
  • An Tang;Ding-Fei Zhang;Liu Yang
    . 2012, 43(07): 817-819.
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    Red-emitting phosphor In2(MoO4)3:Eu3+,Bi3+ has been synthesized by solid-state reaction at 900℃ in air. X-ray diffraction (XRD) and fluorescence spectrometer were used to characterize the samples. The prepared In2(MoO4)3:Eu3+,Bi3+ has a cubic structure with pure phase. Photoluminescence spectra indicate that the phosphor can be effectively excited under the excitation of near-UV light (395 nm) and emit intensive red light at 612 nm. The phosphor In2(MoO4)3:0.4Eu3+ has strong luminescence intensity among Eu3+-doped In2(MoO4)3 phosphors. The photoluminescent intensity reaches the maximum when Bi3+ concentration is 3 mol% in the In2(MoO4)3:0.4Eu3+,Bi3+ and is stronger than that of no Bi3+ phosphor In2(MoO4)3:0.4Eu3+. Compared with CaMoO4:Eu3+, In2(MoO4)3:0.4Eu3+,0.03Bi3+ has stronger luminescence intensity. Therefore the In2(MoO4)3:0.4Eu3+,0.03Bi3+ may be a novel red phosphor for near-UV white LED.
  • Yue Wang;YA-Jun Zhang;Chuan-Jie Zhong
    . 2012, 43(07): 820-822.
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    Based on solution processing, Use two kinds of materials which have different dielectric constant, 2.6 for PMMA and 16 for P(VDF-TrFE).fabricate two different structures of double-layer insulating films on P type silicon substrates and test their high frequency C-V characteristic and leakage characteristics. For Si-PMMA-P(VDF-TrFE)-Ag structure, The capacitance per unit is 35nF/cm2 and leakage current under 40 volt decrease gradually from 7.29×10-7A/cm2 to 3.44×10-7A/cm2 with the number of scans increase. When comes to the Si-P(VDF-TrFE)-PMMA-Ag structure, The capacitance measured is only 15 nF/cm2,And the leakage current is 1.93×10-8A/cm2 at the same voltage. Based on this we analysis the influence of electron traps and electric field strength for the C-V and I-V characteristics in double layer insulating films.
  • You-Feng Li;Hong-Ji Ye;Hu Zhou
    . 2012, 43(07): 823-827.
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    Ce doped yttrium aluminum garnet (YAG: Ce) spherical nanopowder was synthesized by dropping A l(NO3 )3?9H2O , Y ( NO3)3?6H2O and Ce ( NO3 )3?6H2O solution and ammonium hydrogen carbonate solution into the impinging streams reactor simultaneously at the same rate. The precursors and the YAG: Ce powders were characterized by XRD, FTIR, SEM and fluorescence spectrophotometer. The factors affecting the powder characteristics, including the mother salt concentration, the dropping speeds of solutions solution, sintering methods and temperature were analyzed and discussed. The results show that the dispersion, the composition, the morphology and luminescence intensity of the YAG phosphors are affected remarkably by these factors. The YAG powders without any interphases can be obtained at 900 ℃ when the mother salt concentration ( c0= 0.055 mo l/L ) is relatively low. The crystallinity can be increased with the increasing feeding rate at corresponding scope. The pure YAG phase could be obtained by Na2CO3-S-K2CO3 mixture molten calcination method at 700 ℃. Compared with the direct calcination method, the YAG: Ce3+ phase transition temperature with the present method can be decreased about 300 ℃, and the luminescent intensity of as-prepared phosphor can be increased greatly than that prepared by direct baking method.
  • Jiang-Bo Jiang;Ming Xue;Yun-Lai Wu
    . 2012, 43(07): 828-830.
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    We prepared marine magnesium phosphate cement (MPC) based materials by using sea water and sand, then we researched the storage performance, the early strength characteristics and the anti-sea erosion performance of this materials. The results show that the magnesium phosphate cement has good storage performance, after the raw materials was stored with certain storage method for 360 days, the strength of MPC was decreased less than 5%, and after the raw materials was stored for 1000 days, the strength of MPC was decreased less than 10%. The compressive strength of this marine MPC based materials hydrating for 2h was more than 28MPa, the compressive strength of this marine MPC based materials hydrating for 1d had reached more than 52MPa, and the setting time was less than 25min. The marine MPC mortar we prepared has good performance against sea erosion.
  • Yu-Dao Lin;Tao Xu;Qing-Ju LIU
    . 2012, 43(07): 831-834.
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    Formaldehyde gas-sensing properties of Ag-LaFeO3 prepared by sol-gel method combined with microwave chemical method were studied in this paper. The specimen powders were characterized by thermo-gravimetry-differential scanning calorimetry (TG-DSC), X-ray diffraction(XRD) and fourier transform infrared spectroscopy (FT-IR). The results show that the phase of Ag-LaFeO3 powders including Ag and LaFeO3 are perovskite. The sensor of Ag-LaFeO3 synthesized from the AgNO3 and La (NO3)3 precursors with the molar ratio of 1:9 shows the best sensitivity for 1ppm formaldehyde than the others. In addition, the response and recovery time are both about 180s.
  • Li-Jian Wang;Xin Li;Qi-Bing Sha
    . 2012, 43(07): 835-838.
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    In the present work we studied the toluene decomposition activity of cobalt based catalysts prepared by chemical reduction with ethylene glycol (EG), in comparison to catalysts prepared via typical impregnation procedure. The properties of the supported Co catalysts were studied by means of X–ray diffraction (XRD), temperature programmed reduction by H2 (H2-TPR),X-ray photoelectron spectroscopy (XPS), Temperature programe desorptionand (TPD). Activity tests of the catalysts were carried out in a fixed bed reactor. Results showed that the catalytic activity of the catalyst Co/cord-EG prepared by chemical reduction with ethylene glycol was much higher than that of the catalyst Co/cord prepared by the conventional impregnation. The cobalt species presented on the catalyst Co/cord-EG were mainly in the form of cobalt (II) oxide, and those presented on the catalyst Co/cord were in the forms of both cobalt (II) oxide and cobalt (III) oxide. The application of the EG reduction method favored the formation of smaller particles and higher dispersion of cobalt species on the supports. As a consequence of that, the catalytic activity of the catalyst Co/cord-EG was greatly improved in comparison with the catalyst Co/cord pretreated by the traditional impregnation.
  • Zhi-Chun Wang;Sheng-zhou CHEN;
    . 2012, 43(07): 839-842.
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    Supported catalyst calcium chloride/activated carbon (CaCl2/AC) was prepared and used in dehydrochlorination of pentachloroethane to produce perchloroethylene. Influences of reaction temperature, space velocity and CaCl2 loading amount on catalytic activity of CaCl2/AC were investigated. Stability of catalytic activity of catalyst was also studied. Results of experiment showed that the optimal conditions were reaction temperature 240℃, space velocity 3.4h-1,CaCl2 loading amount 0.3mmol?g-1. Under the optimal conditions, the conversion of pentachloroethane and the yield of perchloroethylene can reach more than 99% and 95%, respectively. And the repeatability of catalytic activity of catalyst was fine. The catalysts were characterized by T-ray diffraction (XRD) and nitrogen adsorption-desorption method. The results showed that the dispersion of CaCl2 on activated carbon surface was good . The BET surface area and pore volume of CaCl2/AC Catalyst gradually decreased with the CaCl2 loading amount increased.
  • Yan-Jiao Li;Jing-En Zhou;Chang-Jiang Liu
    . 2012, 43(07): 843-847.
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    BN/EG nanofluid was synthesized through a two-step method. The influencing factors such as time of ultrasonic agitation, pH value and dispersant on stability was investigated. The experimental results indicated that too long or too short ultrasonic agitation time will decrease the stability of BN/EG nanofluids and the optimal ultrasonic agitation time is 30min in current experiment. The addition of acid or alkali will lead to the deterioration of stability of the nanofluids. Proper quantities of PVP can improve the stability of the nanofluids.
  • YONG CHEN;Feng Wang;Ling-Xiang Chen
    . 2012, 43(07): 848-850.
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    Cubic MgZnO nanowires were prepared on silicon substrates by a thermal evaporation method. MgO nanowires could be prepared using Mg powders as the source material. MgZnO nanowires could be obtained using the mixture of Mg and Zn powders as the source materials, with the Zn content of 7 at.% and the diameter of 200-300 nm, and there were hexagonal ZnO nanowires coexisting with the cubic MgZnO nanowires in the product. Both the MgZnO and the ZnO nanowires were single crystals. The Zn content in MgZnO nanowires was much lower than that in the source material, which may be due to the higher vapor pressure of ZnO and Zn than MgO and Mg.
  • Jie Yue;Yi-Ding Shen;Xiao-Juan Lai
    . 2012, 43(07): 851-854.
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    In this paper, two component waterborne polyurethane wood coating were obtained by hydroxyl polyurethane-acrylate(PUA) composite dispersion with synthesized curing agent. The influences of acrylate (PA) content and curing agent on the paint film properties were investigated by particle size analysis and transmission electron microscopy(TEM), respectively.It was found that when the content of PA is 15% and the curing agent is 5%, the waterborne polyurethane wood coating obtained better emulsion stability ,hardness, toughness, impact resistance and more excellent solvent resistance.
  • Gang Chen;Zhan-Fang Liu;Xiao-Wei Feng
    . 2012, 43(07): 855-858.
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  • Yi-Hui Chen;Guo-Ying Li
    . 2012, 43(07): 859-862.
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    Alkali-solubilized collagen solution cross-linked with N-hydroxysuccinimide activated adipic acid (NHS-AA) ester. The effect of NHS-AA on the secondary structure of alkali-solubilized collagen was examined. The infrared bands, determined by the fourier-transform infrared spectroscopy (FT-IR), did not reflect characteristics which were caused the amount of cross-linking, but the results from two-dimensional infrared correlation spectroscopy (2D-IR) indicated that the positive synchronous cross-peaks, derived from stretching vibrations of C=O at 1672 cm-1, C-N stretching vibrations and wagging of N-H at 1554 cm-1 and in plane deformation of N-H at 1241cm-1 of collagen, were indicative of local conformational changes of collagen. The order of secondary structure changes of cross-linked collagen was amide III than amide I than amide II than -CH3 than -CH-. It was shown that the microcosmic information of a change in dynamic structure could be provided for cross-linked collagen with the interruption of the cross-linker concentration. These fundamental data should provide available information for understanding of the relationship between the structure and function of cross-linked collagen.
  • Zhi-Hui Yu;Cui-Hua Ren;Fan Li
    . 2012, 43(07): 863-867.
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    Nano-Polypyrrole(PPy) were prepared on glassy carbon(GC) electrodes by electrodeposited method. The morphology of the PPy was obtained by scanning electron microscopy (SEM). The GOD/PPy/GC electrode was prepared by immobilization glucose oxidase(GOD) on the PPy . The electrocatalytic properties of GOD/PPy/GC electrode were characterized by cyclic voltograme method;The results showed that GOD can be immobilized on the nano-PPy and the Biological activation of GOD was retained. The GOD/PPy/GC electrode exhibits good eleccatalytic performance without any electron mediator at the medium of phosphate buffer (0.1mol/L).
  • Jin-Qiong Fan;Feng Wang
    . 2012, 43(07): 868-871.
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    Titanium dioxide (TiO2) particles composed of anatase, were prepared by a hydrolytic method at interface of butanol and water from trabutoxytitanium. The polyamide thin film nanocomposite (TFN) membranes were formed on the top of polysulfone ultrafiltration membranes by interfacial polymerization in the presence of TiO2 either in trimesoyl chloride (TMC)/n-hexane solution or in m-phenylenediamine (MPD) aqueous solution. The structure and performance of the new TFN membranes loaded with TiO2 were characterized by standard protocols. According to SEM morphologies, the TiO2 particles were found in the bottom of skin layer and finger-like pore of polysulfone support layer when they were added in MPD aqueous solution. When the TiO2 particles were added in TMC/n-hexane solution, the surface morphology of the TFN membranes is compact and exhibits the familiar “peak and valley” and TiO2 particles are visible on the membrane surface. The TFN membraness with TiO2 added in the TMC organic phase had presented better performance than which with TiO2 added in MPD aqueous solution. The antibacterial experimental had revealed that the hybrid TFN membranes loaded with TiO2 possess excellent bactericidal effect on Escherchia coli (E. coli) under UV light irradiation.
  • Xu-Dong Zha;Yong-Qiang Chen;Jing Chen
    . 2012, 43(07): 872-876.
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    In order to determine a reasonable carbon fiber contents for the conductive asphalt mixture with carbon fiber, the chopped polyacrylonitrile (PAN) based carbon fiber was selected as a conductive phase material. Many laboratory experiments were conducted to analyze the effect of the carbon fiber contents on the Marshall performances and the conductive performances for the AC-13C of conductive asphalt mixture and then verify its pavement performances. The results show that, under the same asphalt-aggregate ratio, with the increases of the carbon fiber contents, the bulk volume density, the voids filled with asphalt and the Marshall stability of the conductive asphalt mixture are appeared the trend from increasing to decreasing, the volume of air voids and the voids in mineral aggregate are changed as the relation from decreasing to increasing, but the flow value is increased continuously. The technical standards of AC, adjustment and SMA were applied to the asphalt mixtures with the different ranges of carbon fiber content, respectively, and the reasonable optimal asphalt-aggregate ratios were determined. There is a good semilogarithm correlation between the optimal asphalt-aggregate ratios and the carbon fiber contents. Under the optimal asphalt-aggregate ratio, a good correlation of power function is showed between the logarithms of electrical resistivity and the carbon fiber contents for the conductive asphalt mixture. All the pavement performances of asphalt mixture with 0.1% of carbon fiber content have attained the technical requirements of modified asphalt mixture and SMA in the climate conditions with high demand. Therefore, the suitable carbon fiber content can play an excellent role in reinforcing the conductive asphalt mixture and then form the stable conductive network. The technical requirements of various performances and conductive heating are integrated to recommend the suitable carbon fiber content as 0.1%.
  • Wei-Hong Sun;Xin Yan;Xi Zhu
    . 2012, 43(07): 877-879.
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    The effect of catalyst and reaction temperature on the reaction kinetics of p-Methylphenol end-capped with polyurethane was studied by Fourier transform infrared spectroscopy (FTIR) technique. The results showed that triethylamine could increase the speed of p-Methylphenol end-capped with polyurethane prepolymer reaction; The activation energy of this reaction was reduced to 5.4 kJ/mol when adding 0.2%triethylamine catalyst, compared with that was 15.16kJ/mol without catalyst; Moreover, the end-capped reaction was first-order reactions when adding triethylamine catalyst while that was second-order reactions without catalyst
  • Cui-Li Li;Zhong-Qiang Shan;Jian-Hua Tian
    . 2012, 43(07): 880-883.
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    A series of sulfur composite materials which used acetylene black, aphanitic graphite,Cabot Vulcan XC-72 carbon black and Cabot Bp2000 Super conductive carbon black were prepared. The physical structures were determined by X-ray diffraction,scanning electron microscopy and specific surface area measurements. The electrochemical performances of the sulfur composite material were characterized by cycling test.The results indicate that: factors such as surface morphology, pore size distribution and specific surface area of the matrix materials can affect the electrochemical performance of the composite materials.In this paper,the best matrix material is Bp2000 super conductive carbon. Its initial discharge specific capacity is 1385.1mAh/g. The specific capacity still keep as high as1080.2mAh/g, after 30 cycles at room temperature just 22% fade.
  • He-Li Ma;Kun Song;Liang Zhou
    . 2012, 43(07): 884-887.
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    we use the electrochemical deposition self-assembly method to fabricate a metamaterial absorber with nanoscale silver dendritic pattern unit. The metamaterial absorber is consisted of “unit-dielectric-metal” structure, which contains randomly distributed silver dendritic pattern units with diameters of 70-140nm, PVA dielectric interlayer and nanoscale silver metal plane. By means of changing the deposition conditions, such as deposition voltage and concentration of PEG, the absorption peak quantity and absorption magnitude of the metamaterial absorber can be modulated. The experiment result shows that the absorber can realize multi-frequency absorption at 538nm and 656nm with the magnitude of 21.1% and 24.8%. The fabrication of this large structure area metamaterial absorber has the advantages of easy processing and low cost.
  • Ming-Guang WANG;Yang Qi
    . 2012, 43(07): 888-891.
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    The La0.7Ca0.3MnO3 films were prepared by pulsed laser deposition on a (100) LaAlO3 substrate at the temperature between 600 and 800℃. The microstructure of these films was studied by high resolution electron microscopy. The results show that La0.7Ca0.3MnO3 films were epitaxially grown on LaAlO3 substrates at the temperatures chosen and were composed of a lot of columnar grains. The oriented relationship between film and substrate was identified as follows: (ⅰ) (100)f∥(001)s, [011]f∥[100]s,(ⅱ) (011)f∥(001)s, [100]f∥[100]s. The film has lamella domain structure, that is, the film close to the substrate shows (ⅱ)-domain and the upper lamella shows a complex of (ⅰ)and (ⅱ)-domains. Anti-phase domains and twins were also observed in these films. The misfit dislocations between films and substrates were seldom seen in these films. The films grow in a mode of Stranski-Krastanov.
  • Wen-Jing Guo;Baao-Zhong Zheng;Qing-Mei Yuan
    . 2012, 43(07): 892-895.
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    Microcapsules containing styrene were synthesized in an oil-in-water emulsion with poly (Urea Melamine and Formaldehyde resin) as the shell material and styrene as the core substance for self-healing thermoplastic materials. The chemical composition , the shape and surface morphology of microcapsule were analyzed by infrared spectroscopy(IR),scanning electron microscopy(SEM)and Nano-Particle Size Analyzer, respectively. The surface was found to be dense and rough. Studies showed that the shape of microcapsules was spherical and its size distribution was concentrated and the core content was 72%. It may be used in self-healing materials.
  • Xin-Zheng Li;Wei-Dong Lai;Xiao-Wei Li
    . 2012, 43(07): 896-898.
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    The light-thermal sensitive microcapsule is synthesized with interfacial polymerization method, which is a new type of optical information recording function material. It is investigated that the dye ODB-2 effects on the excitation state of photoinitiator and the polymerization property in microcapsule by fluorescence spectrum and infrared spectrum. The results show that photo-absorption of dye precursor in ultraviolet region causes the fluorescence spectrum intensity of photoinitiator to decrease, and make the number of molecules in excited state reduce. The quantum yield of primary radical and proceeding of photopolymerization is affected by the dye precursor. The speed and extent of polymerization in microcapsule decrease as dye precursor concentration increases. The degree of influences of different kinds of dye on photo-polymerization is different.
  • Ting-Ting Yang;Shi-Rong Wang;Xiang-Gao Li
    . 2012, 43(07): 899-903.
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    In order to improve the surface morphology and strength of UF resin electrophoretic microcapsules, the microcapsules was modified by gelatin as a modifier. The preparation conditions of gelatin-UF resin electrophoretic microcapsules had been studied in this paper. The microcapsules with smooth surface, compact structure and high strength could be obtained at the optimal condition of the preparation, in which the pH is 9.0~9.5 in the process of addition reaction and 3.0~3.5 in the condensation polymerization step,respsectively, when the mass fraction of the gelatin is 0.5%(w/w) in reaction system. The model display device was prepared by the coating of microcapsules. When the applied electric field is15V, the reflectance of the display device is 39.6% in white state, and 4.4% in black state, the contrast ratio is 9.0, and the response time is 460ms. The device shows the excellent display performance and therefore the display device of eight segment clock and active matrix which has the property of quick response and high contrast could be obtained.
  • Jie Deng;Jie Tao;Jie Gao
    . 2012, 43(07): 904-907.
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    Polyaniline/titanium dioxide (PANI/TiO2) composite film electrodes were deposited on flexible conductive plastic substrates using the “doctor blading” method by PANI/TiO2 composite sol which was prepared by in situ chemical oxidation polymerization of aniline in the presence of acid TiO2 sol. The PANI/TiO2 composite sol and the composite film were characterized by FT-IR, XRD, TEM, UV-Vis spectroscopy and the photocurrent density vs applied electrode potential curves. The results showed that the composition between TiO2 and polyaniline in structure was achieved and the incorporation of polyaniline enhances the availability of the sun light. The photoelectric properties of PANI/TiO2 composite film electrodes were improved with the addition of polyaniline. The preparation of PANI/TiO2 film using composite sols expands the scope of substrates.
  • Hua Xin;Xiao-Rui Li;Yi-Ding Shen
    . 2012, 43(07): 908-911.
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    The perfluorinated acrylate modified cationic polyurethane (FAPU) hybrid emulsion was prepared and characterized by IR and F19NMR.The FAPU hybrid emulsion was used for paper surface sizing. The emphasis was put on the influence of the content of MDEA as cationic extender and the content of FA as functional monomer on the paper properties. The contact angles result showed that the water and oil-repellency property of the papers treated with FAPU increased and then decreased with the MDEA content increase, while the water and oil-repellency property both increased with the increase of FA content. The initial contact angles of water and liquid paraffin on the paper treated with FAPU of 30% content FA were 132o and 114o, respectively. In addition, the contact angles changed little within 300s which indicated that the paper treated with FAPU possessed good water and oil-repellency ability. The mechanical property test results showed the paper tensile strength increased with the increase of the MDEA and FA content. At last, the surface and crosssection of the paper untreated and treated with FAPU were observed by SEM, respectively. The result showed that the fibers of the treated paper more closely combined.
  • Yan-Jie Zhang;Xiang-Yun Deng;Li-Ren Han
    . 2012, 43(07): 912-914.
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    The BaTiO3 ceramics with high dielectric constant have been prepared by sol-gel combing twice-sintering technique. The system has been indicated the coexist of tetragonal and cubic phases from the X-ray diffraction pattern and crystal partial size is 1 micron from the scanning electron microscope pattern , the maximum dielectric constant has reached 38306 with TF2000 Analyzer under testing conditions of room temperature and small signal frequence 100Hz. The effects of temperature, frequency and applied electric field on switching current of BaTiO3 ferroelectric ceramic have been studied in the paper, it is found that the domain switching current slowly decreases with increasing temperature and sharply increases with increasing frequency and applied electric field. The results obtained also can be interpreted by the factors of the temperature and electric field from the viewpoint of energy analysis.
  • Wei-Jie Liu;Zheng-Hao Sun;Bo Zhou
    . 2012, 43(07): 915-918.
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    At low temperature, colloidal crystal template was prepared by one-substrate vertical deposition. In the formed colloidal crystal, large areas of square array were observed, because thermal motion of particles is inhibited at low temperature and dislocation is happened. Subsequently, Ag nanoparticles and titania were deposited one by one on the PS spheres by an electroless plating method and sol-gel technology. Finally the sample was calcined to remove the colloidal crystal template and the ordered hollow Ag/TiO2 spheres with square array were successfully prepared. The sample was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the sample clearly retains its original square array of the colloidal crystal template and possesses highly ordered nanostructure. We chose photodegradation of methyl orange to evaluate the photocatalytic ability of square ordered hollow Ag/TiO2 spheres. For comparison, we also evaluated the photocatalytic activity of flat TiO2 film and square ordered hollow TiO2 spheres. The results show that the as-prepared ordered hollow Ag/TiO2 sphere exhibits the most efficient photocatalytic activity. The long-range ordering porosity and the addition of Ag nanoparticles are the main factors leading to the improved photocatalytic activity.
  • Jing-Hua Yi;Xiu-Zhou Lin;Min-Hao ZHU
    . 2012, 43(07): 919-923.
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    By changing the angle displacement amplitude, torsional fretting corrosion behaviors of Ti6Al4V alloy were studied in 25% serum solution of 37 ℃ in the new torsional fretting corrosion test device at constant temperature. The results showed that the angle displacement amplitude had an important effect on corrosion behaviors and running regimes of torsional fretting. The friction torque - angular displacement amplitude (T-θ) curves showed linear, elliptical and parallelogram type.Torsional fretting running regimes of Ti6Al4V alloy presented partal slip regime, mixed regime and slip regime. When the angle displacement amplitude was small, the torsional wear occurred at the edge of contact area and the damage was slight; torsional fretting had almost no influence on corrosion ,and the fluctuation of corrosion current and corrosion potential versus time curve was small.With the angle displacement amplitude increased, a strong plastic deformation occurred in the contact surface and the damage was severe. Corrosion current and corrosion potential versus time curves showed that the torsional fretting influenced corrosion strongly and wear accelerated corrosion.
  • Yan-Ming Wang;Guang-Jian Wang;Su-Fang Ding
    . 2012, 43(07): 924-926.
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    Porous spherical Li2MnSiO4/C composite was prepared via a wet ball milling-spray drying method and exploited as cathode material for lithium ion batteries. X-ray diffraction (XRD) pattern of the sample conforms the formation of orthorhombic Li2MnSiO4 with Pmn21 space group. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show that the aggregated spherical particles in diameter of ca. 10 μm are composed of large numbers of nanoparticles with size of ca. 25 nm. The Li2MnSiO4 nanoparticles are covered with a carbon layer of ca. 3 nm thick . The electrochemical test reveals that the initial discharge capacities of Li2MnSiO4/C are 153 mAh/g and 110 mAh/g at 0.05 C and 0.5 C rate, long with the capacity retention of 80% and 66% after 50 cycles, respectively.
  • yao-wu zhao;Lihua LiLI Hong;bo li;
    . 2012, 43(07): 927-931.
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    ABSTRACT: This study investigated the role of calcium alginate gel in the occlusion and mineralization of dentinal tubules to treat dentine hypersensitivity.. Calcium alginate gel was formed from sodium alginate (SA), calcium carbonate and gluconolactone (GDL) by in situ phase transition on dentin. The gel formation time and the pH value of the extract were measured with changes in a single variable of calcium alginate concentration, f value (the molar ratio of calcium ion and carboxyl) or n value (the molar ratio of GDL and calcium ion). The structure and morphology of dentinal tubules were observed by Scanning Electron Microscopy (SEM) before and after the calcium alginate treatment. The results showed that the gel formation was optimized at sodium alginate concentration of 2.5%, f value of 0.5 and at n value of 0.6. The open tubules became narrower or occluded after the calcium alginate treatment. Layers of dense mineral deposits were seen on the surface of the gel in the dentinal tubules. The XRD analysis demonstrated that the mineral deposits were highly crystallized hydroxyapatite (HA) only. Altogether, our results indicate that calcium alginate mixture occludes the dentinal tubules by intratubular gel formation, and that the formed gel induces the deposit of highly crystallized HA providing a new way of further exploring the dentin biomineralization.
  • Yong-Huang TONG;Ye-Wei Fu;Le-hua QI;
    . 2012, 43(07): 932-935.
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    Aligned short carbon fibre (Aligned Csf) and 2.5D carbon fabric reinforced magnesium alloy composites were fabricated by vacuum infiltration-semisolid extrusion technology. The microstructure of composites were observed, the coefficient of thermal expansion(α) of composites between 30℃ to 350℃ were measured, and the corresponding theory models for predicting the α were modified based on Schapery model. The results show that the α of composites was increased with the temperature increased between 30℃ to 200℃, however the α of composites was decreased or tended to stability when the temperature exceeded 250℃. the α didn’t increased continuously with the temperature increased, which was due to the solubility of aluminum element increased, Magnesium alloy occurred plastic deformation; The errors between the theory values of revised model and the experimental values were all less than 5%, which indicated the theory model could predict the α of experimental effectively.
  • Zhi-Qiang Xie;Jin-Ming Huang;Xian-Hong Chen
    . 2012, 43(07): 936-939.
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    A novel kind of composite foaming agents for rigid PVC(R-PVC) was prepared from modifying azodicarbonamide (AC) with kickers (carbamide, zinc carbonate) and sodium bicarbonate. The samples were analysed with thermal analysis and gas volume test. The results indicate that the novel composite foaming agent with a mass ratio of 10︰10︰2.5︰2.5, which represent AC, carbamide, zinc carbonate and sodium bicarbonate respectively, poses optimized properties: its decomposition temperature lies within the temperature range suitable for R-PVC processing, its endotherm equals exotherm on the whole and this composite foaming agent has a high volume of liberated gas but without any abruptness. R-PVC foam manufactured with this composite foaming agent has better mechanical properties, and its SEM images present fine microcellular structure.
  • Zhan-Hua Huang;Bing Zhang;Li Zhou
    . 2012, 43(07): 940-943.
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    Silk-like fungus fibre with micrometer size was prepared via fungus method. SEM, FTIR, CP/MAS13C-NMR and XRD were used for the microtopography and chemical structutre analysis of the obtained fungus fibre. Result of SEM indicated that the fungus fibre is silk-like within micrometer size (0.8μm), which formed a distinct 3-D network. The result of FTIR revealed that the fungal cellulose contain primaryly –OH, -C-O-C-, -CH2 and -CH2CONH- groups. Chemical shift of fungal cellulose is similar with that of bacterial cellulose, together with high content of I-type crystal cellulose and non-crystal compounds. The characteristics of fungus fibre revealed its potential as templates and reinforced polymer material.
  • Liang-Feng JIang;Xiu-Lin Ji;Shun-Zhen Yang
    . 2012, 43(07): 944-948.
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    Abstract:With the variation of impingement velocity, sand content and sand size, erosion-corrosion behavior of amorphous Ni-P electrodeposits was investigated using model MSH erosion-corrosion equipment in this paper. Results show that the mass loss rates of erosion and erosion-corrosion are increased with impingement velocity, sand content and sand size. Compared with AISI 304 SS, the mass loss rate of erosion and total mass loss rate of amorphous Ni-P electrodeposits are higher, but mass loss rate of corrosion is lower. And it also suggests amorphous Ni-P electrodeposits has good erosion-corrosion resistance. The erosion-corrosion mechanism of rod amorphous Ni-P electrodeposits is lip and fracture on its frontal side and cutting and furrow on its lateral side.
  • Dong-Ying Li;Jun-Fu Wei;Kong-Yin Zhao
    . 2012, 43(07): 949-952.
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    In this paper, the functional fiber (PP-g-CaSiO3) was prepared by coating of sodium silicate (Na2SiO3) and then crosslinking of calcium chloride (CaCl2) on the acrylic acid (AA) grafted polypropylene (PP) fiber. FTIR spectroscopy, BET measurement and Scanning Electron Microscopy (SEM) analysis indicated that CaSiO3 was successfully grafted onto polypropylene fiber, and the specific surface area of fiber increased significantly. The adsorption of bisphenol A (BPA) on PP-g-CaSiO3 was also studied. The results showed that the data of BPA adsorption on the fiber sample were fitted to the Langmuir isotherm model and second-order kinetics equation, and its saturated adsorption capacity reached 39.23 mg/g.