20 September 2011, Volume 42 Issue 09
    

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  • Phase behaviors of liquid crystals under confined conditions(1) Effects of different physical confinements
    WANG Xiaotao;BI Shuguang;PENG Haiyan
    . 2011, 42(09): 1543-1546.
    Abstract ( ) Knowledge map Save
    Liquid crystals (LCs) as functional materials have wide applications in display, information storage, anti-counterfeit, et al. The review summarized the researching progress on phase behaviors of LCs under physical confinements such as micro-channels, polymer matrixes and supermolecular gels. Under confinement of micro-channels, the phase transition of LC molecules depends on the size of micro-channels and interface interaction between LC and the wall of micro-channels. When the size of micro-channels is larger than the critical value, the liquid crystal-isotropic transition is first order. However, when the size of micro-channels is smaller than the critical value, the liquid crystal-isotropic transition is second order, and the surface-induced orientation improves the stability of LC phases. For polymer/LC composites, there exists a obvious phase separation between LCs and polymer at high content of polymer, and the phase transition and crystallization temperatures of LC tend to increase with the content of LCs, and the glass transition temperature of polymer matrix decreases due to plasticization effect of LCs; At low content of polymer in composites, the polymer networks improve the stability of LC phases, especially blue phase LCs. And supermolecular gels could adjust the phase structure and properties of LCs.
    • 研究与开发
  • Antifatigue Mechanism of Cold-extruded Internal Thread Based on High-strength Steel
    MIAO Hong;ZUO Dunwen;ZHANG Ruihong
    . 2011, 42(09): 1547-1550.
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    According to the forming process of cold-extruded internal thread of high-strength steel，the effect of parts status on the fatigue properties of internal thread was studied from the microscopic viewpoint, such as residual stress, surface roughness, microhardness, hardened layer, etc. The results showed that the metal surface of cold-extruded internal thread had a long fibrous structure, and it appeared to be streamline type and distributed along the normal direction of the tooth surface. The grains were pressed and refined, and the dislocation density was increased significantly. The work hardening phenomenon was appeared, and made the strength and the hardness of the metal increase. The residual compressive stress field formed on the surface of the metal could eliminate the impact of stress concentration, reducing fatigue notch sensitive, extending period of crack forming and slowing or restraining the expanding of the crack. The surface of cold-extruded internal thread had obvious finish mark, and its smooth of the surface was well. The surface roughness could be eliminated effectively, and reducing stress concentration and contributing to increasing the fatigue properties of internal thread.
  • Research on the Removal Mechanism of Phosphorus from Polysilicon by Vacuum Induction Melting
    LUO Dawei;SUN Jinling;ZHANG Shuang
    . 2011, 42(09): 1551-1554.
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    Phosphorus is one of the main impurities in polysilicon. Currently, its content in polysilicon can not be reduced to level required by solar grade silicon (SOG-Si) through acid leaching and directional solidification processes. It can be effectively removed by vacuum melting as phosphorus in silicon has a higher vapor pressure. The vacuum melting furnace and directional solidification furnace which were designed by us were used to refine metallurgical grade silicon (MG-Si) under vacuum conditions. The effect of the vacuum degree, refining times and refining temperatures on phosphorus removal was investigated, respectively. The relationship of phosphorus content in SOG-Si with refining times and refining temperatures was derived. And the thermodynamic and kinetic of phosphorus removal process under vacuum induction melting was also analyzed.
  • PbI2 Thick Films Prepared by Close-spaced Sublimation and Its Properties
    ZHU Xinghua;YANG Dingyu;SUN Hui
    . 2011, 42(09): 1555-1558.
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    Polycrystalline PbI2 thick ?lms were grown on glass substrates using close-spaced sublimation(CSS) technique, and its structural, morphological and photoluminescent(PL) properties as a function of depostion condition were investigated. It is found that the deposition rate increases rapidly with increasing sublimation source temperature and decreasing deposition pressure. The crystal structure and surface morphology of samples as function of deposition rate was characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results reavealed PbI2 thick ?lms have a layered hexagonal structure, formed by the stacking of (001) plane, with a prefferred [001] orientation, and the grain size decreases with increasing deposition rate. meanwhile, the (001) diffraction peaks( ) was shifted towards large-angle as a result of decreasing lattice constant attributes to increasing films compressive stress. The SEM images of samples also show that the [001] orientation( axis) of layered grains is parallel to the substrate, and its ordering degree as well as film density reduces with the increases of deposition rate. Furthermore, high deposition rate also presents “hexagonal center” subgrain, grown perpendicularly on the layered grains, lead to a dramatically improve in surface roughness. Finally, the samples PL spectra only exhibit intrinsic luminescence, and the PL peak shifted to longer wavelengths with braoden peak width and lower intensity, owing to increasing deposition rate.
  • Modification of nano carbon black particles to obtain surface charge for Electronic ink
    ZHANG Junhong;LUO Chunrong;ZHAO Xiaopeng
    . 2011, 42(09): 1559-1562.
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    Abstract: The surfaces of nano carbon black particles were modified by silane coupling agent 3-Triethoxysilylpropylamine (KH550) and concentrated sulfuric acid. Manifested by transmission electron microscope, ultraviolet-visible spectrophotometer UV4100, there were almost no changes in the size and color purity of between the unmodified and modified carbon black particles; Electrophoretic display (EPD) experiments of the modified nano carbon black particles show that the conductivities of carbon black whose surfaces were positively or negatively charged, have been converted to very low from high. The modified nano carbon black particles have good electric field response characteristics and reversible movement at low voltage.
  • Isothermal crystallization of PLGA filled with surface grafting treatment of n-HA
    Jiang Liuyun;XIONG Chengdong;LI Qing
    . 2011, 42(09): 1563-1568.
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    The influence of n-HA with surface grafted low molecular weight PDLLA on the isothermal rystallization and melting behaviour of PLGA were investigated by DSC. The Avrami equation had been used to analyze isothermal crystallization, and the correlative kinetics parameter values were given. Moreover, the crystal morphology of them were observed by a polarized optical microscopy(POM) with automatic hot-stage thermal unit. The results showed that the Avrami equation was suitable for describing the isothermal process in this system. The fastest crystallization temperature of the two n-HA/PLGA composites and PLGA were all at 110℃, and the crystallization rate slowed with increasing crystallization temperature. However, the surface grafting treatment of n-HA had a poorer effect on the crystallization rate, melting point and crystallization activiation engery of PLGA than that of the unmodified of n-HA. Besides, the POM results showed the crystal morphology of the two n-HA/PLGA composites and PLGA were similar, and the nucleation speed of them were all lower with the higher crystallization temperature. However, the n-HA/PLGA composites with unmodified n-HA particles displayed the highest nucleation speed among the three samples. It indicated that the unmodified n-HA acted as an more effective heterogeneous nucleating agent than the surface grafting treatment of n-HA. All the results showed the surface grafting treatment of n-HA had better bonding interface, so that it had a poorer nucleating effect on the crystallization of PLGA, comparing with n-HA/PLGA composite filled with unmodified n-HA.
  • Structure and properties of electrospun PLLA/PCL/PEG blend fibrous membranes
    JIANG Kaifeng;LIAO Guiying;XIA Hua
    . 2011, 42(09): 1569-1572.
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    Poly(L-lactide) (PLLA)/poly(ε-caprolactone) (PCL) /polyethylene glycol(PEG) blend fibrous membranes were prepared by electrospinning. The effect of solvent volume ratio, polymer blending weight ratio and solution concentration on their morphology were investigated. Their thermal stability, crystallinity, mechanical properties and hydrophilicity were characterized. Due to the incorporation of PEG, the thermal stability and crystallinity of the fibrous membranes were improved, and their tensile strength, Young’s modulus and hydrophilicity were also enhanced.
  • Synthesis and characterization of novel organic polymer-inorganic hybrid materials ZnPS-PVPA
    HU Xiaoyan;FU Xiangkai;HUANG Jing
    . 2011, 42(09): 1573-1576.
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    A new type of zinc poly(styrene-phenylvinylphosphonate)-phosphate Zn(NaPO4)1-x(O3PG)x·mH2O (x=0.35~1.0, G is organic group) in a series of stoichiometric ratios was synthesized in the absence of template agent in this paper. The phenylvinylphosphonate and sodium dihydrogen phosphate have been used as phosphorus resource. These compounds were well characterized by FT-IR、N2 volumetric adsorption、TG、XRD、SEM. The results showed that the new hybrid materials with regular layered structure, determinate surface area and thermal stability could be used as a new type of catalyst support materials.
  • Effects of Nb2O5 Addition on the Magnetic Properties of Mn-Zn Ferrite Materials with High Initial Permeability and Low Specific Loss Factor
    HU Feng;LIU Xiansong;ZHU Deru
    . 2011, 42(09): 1577-1579.
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    Mn-Zn ferrite materials with high initial permeability and low specific loss factor were prepared by the conventional ceramic technology. The effects of Nb2O5 dopant on the magnetic properties were researched. The results showed that Mn-Zn ferrite，which was doped with 0.015wt% Nb2O5, had a good soft magnetic property with the initial permeability μi=13386, the specific temperature factor of initial permeability αμ/μi=-0.6×10-6/K and the specific loss factor tanδ/μi=3.2×10-6.
  • A novel method for preparation of zinc oxide nanoparticles
    ZHANG Menglei;SUN Lei;ZHAO Yanbao
    . 2011, 42(09): 1580-1583.
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    A novel method to prepare ZnO nanoparticles is proposed in this paper. This method is based on the reduction of Zn(NO3)2 in liquid ammonia solution of sodium and subsequent oxidization of the newly formed Zn particles in the ambient air. To investigate the effects of surface modification on the morphologies, sizes and properties of the as-synthesized powders, sodium dodecyl sulfate (SDS) modified ZnO nanoparticles were also prepared. The structures and morphologies of samples were characterized by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry and differential thermal analysis (TG&DTA). The results show that the as-synthesized ZnO particles exhibit a hexagonal wurtzite crystal structure. The unmodified ZnO particles aggregate severely, but the surface modified ZnO nanoparticles exhibit a rod-like morphology and disperse well. FI-IR and thermal analysis show that SDS does exist on the surface of modified ZnO nanoparticles. The optical properties of samples were investigated by techniques of UV-visible spectroscopy (UV-vis) and room temperature Photoluminescence (PL). The results show that the as-synthesized samples possess the characteristic absorbance bands of ZnO. The method proposed in this paper can be used extensively to prepare other metal and oxides nanomaterials.
  • Effects of natural fiber powder on the structure and performance of polyvinylidene difluorid membrane
    ZUO Danying;LI Hongjun;WANG Yan
    . 2011, 42(09): 1584-1587.
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    Down powder/PVDF composite membrane and ramie powder/PVDF composite membrane were prepared by the solution phase inversion method, and membrane structure and performances were measured. The experimental results revealed that the porosity and water fluxes decreased gradually as the following order of ramie powder/PVDF composite membrane, down powder/PVDF composite membrane and PVDF membrane. While the membrane crystallinity increased according to the above order. These three membranes displayed the same membrane morphology with the dense skin layer and the porous sublayer. But the water-absorbability reduced in sequence of down powder/PVDF composite membrane, ramie powder/PVDF composite membrane and PVDF membrane. These results showed that porosity had a significant influence on membrane water fluxes and membrane water-absorbability was controlled by hydrophilicity of fiber powder. For membrane mechanical properties, fiber powder addition made PVDF membrane strength enhance with the elongation reduction.
  • Highly Selective Fluorescence Detection of Cu2+ by the Schiff base of EDA-NECD
    HAN Qiaorong;JIANG Yuliang;WANG Bingxiang
    . 2011, 42(09): 1588-1590.
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    The schiff base of EDA-NECD was synthesized. Its structure was characterized by using IR, Uv and 1HNMR. The fluorescent and the influence of different transitional metal ions such as Co2+、Ca2+、Zn2+、Cu2+、K+、Ni2+、Mn2+、Pb2+ on this schiff base were studied systematically. The results showed this schiff base exhibited a highly selective fluorescence quenching effect by Cu2+ ions, while other metal ions almost no quenching happened. The absorption spectra increased with the addition of Cu2+ into the solution of EDA-NECD, suggesting that chemical reaction occurred between the Cu2+ and EDA-NECD. This schiff base is promising to be the probe for the Cu2+ .
  • Ag nanoparticles loaded on multi-walled carbon nanotubes and their electrocatalytic effect on oxidation of methanol
    LIU Xuegang;DU Feipeng;DING Yigang
    . 2011, 42(09): 1591-1594.
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    Silver nanoparticles loaded on multi-walled carbon nanotubes (AgNP@MWNT) had been successfully prepared with water-soluble poly (sodium 4-styrenesulfonate-co-acrylic acid) (PSA) grafted MNWT as template, and their electrocatalytic effect on oxidation of methanol was studied in alkaline state. Due to PSA grafted on MWNT, the AgNPs were uniformly loaded on the surface of MWNT with size of 2-4 nm, and the interface between AgNP and MWNT was enhanced greatly. Additionally, AgNP@MWNT had good dispersivity in water, good electrocatalytic activity and tolerance to poisoning species in the oxidation of methanol.
  • Microstructure and Properties of WC-8Co Superfine Coating on Cast Iron by Electro-spark Deposition
    GAO Yuxin;ZHAO Cheng;YI Jian
    . 2011, 42(09): 1595-1598.
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    The cast iron surface is strengthened with the electrode of WC-8Co cemented alloy using electro-spark deposition (ESD) technique. The microstructure and properties of the coating were investigated by X-ray diffraction, scanning electron microscopy and Vickers hardness tester. The results show that ESD technique can produce dense coating on surface of the cast iron with proper process parameters. The coating consists of Fe3W3C, Co3W3C, Fe7W6 and W2C phases, and metallurgically bonded with the cast iron substrate. Nanometer-sized Fe7W6 and W2C particles dispersedly distribute in the coating. The maximum hardness of the coating is 1512.1 HV0.3, and its wear resistance is 2.3 times of the substrate. The wear mechanism includes abrasive and fatigue wear. Superfine hard phases which distribute dispersedly in coating are the main factors leading to high hardness and wear resistance of the coating.
  • Study on Dynamics of Magnetostrictive Thin Film in Hard Axis
    WANG Fuji;JIA Zhenyuan;LIU Huifang
    . 2011, 42(09): 1601-1605.
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    High driving frequency of magnetic field is one of the key factors which restrict the popularization and application of giant magnetostrictive thin film device. The research on how to reduce the magnetic field driving frequency of giant magnetostrictive thin film device has important significance to the popularization and application of this kind of device. Based on the deep analysis of fundamental reason which cause giant magnetostrictive thin film existing anisotropy, combining the motion mechanism of domains in the magnetostrictive process of thin film, the paper puts forward a new idea that as long as it is able to overcome the demagnetizing field existing in giant magnetostrictive thin film, better dynamic characteristics can be obtained in the direction of hard magnetization axis under low driving frequency of magnetic field. An experiment is carried out in the hard magnetization axis experimental system of giant magnetostrictive thin film. The results show that it is able to make the thin film generate superharmonic resonance with excellent response through applying a suitable bias magnetic field to overcome demagnetizing field. The experimental results provide a new way for reducing the diving frequency of giant magnetostrictive thin film device.
  • Preparation and Characterization of Wheat Straw MCC for Synthetic Leather
    LI Jinbao;ZHANG Meiyun;LIU Yinshan
    . 2011, 42(09): 1606-1609.
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    Microcrystalline cellulose (MCC) applied as an excellent micropore and thickening agents in wet-process production of PU and PVC synthetic leather could give comfortable feeling and good elasticity to them. However, cotton pulp and wood pulp resources commonly used to produce MCC for synthetic leather are very limited. The study was undertaken to obtain MCC from bleaching wheat straw pulp by means of chemical treatment, enzyme treatment and mechanical treatment. This paper emphased on the effect of conditions of acid hydrolysis on performance of MCC, and the optimization of process parameters. Morphology, particle size, crystallinity and thermostability of MCC were characterized by scanning electron microscopy, X-ray diffraction, TGA spectrograph. It is suggested that MCC from wheat straw pulp could meet the requirements of synthetic leather industry standards for MCC, and replace the current PU synthetic leather MCC products based on cotton and wood pulp.
  • The effects of Ag-doped to the Ag-V/TiO2 catalysts with low Vanadium loadings for DeNOX
    WANG Zaihua;LI Xingjun;SONG Wenji
    . 2011, 42(09): 1610-1613.
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    A series of Ag-doped Ag-V/TiO2 catalysts with low Vanadium loadings were prepared by the sol-gel methods for selective catalytic reduction (SCR) of NOX with ammonia as reductant, using tetrabutyl titanate, ammonium metavanadate and silver nitrate as raw materials. The catalysts were characterized by X-ray powder diffraction (XRD), X-ray photoelectron spectra (XPS), temperature programmed reduction (TPR), Thermogravimetry-Mass Spectrometry (TG-MS) and Fourier transform infrared spectroscopy (FTIR).The activity was also investigated. The results showed that the low temperature activity improved and the high temperature activity increased firstly and then decreased with the increasing of Ag amounts. The durability of the catalysts was good. Silver doping inhibited the growth of crystal size, reduced the activation energy of surface oxygen, the bond energy of V=O and the reduction temperature of vanadium oxides.
  • Preparation and characterization of polymer electrolytes based on polymeric ionic liquid
    DU Qiuliang;FU Xiangkai;LIU Sujuan
    . 2011, 42(09): 1614-1618.
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    N-Vinylimidazole, methyl bromoacetate and lithium trifluoromethanesulfonimide (LiTFSI) being the materials, poly(methyl 2-(3-vinylimidazolidin-1-yl)acetate tri?uoromethanesulfonimide (PMVIm-TFSI) was synthesized by solution polymerization. Different composition of polymer electrolytes were prepared by blending PMVIm-TFSI with LiTFSI and poly(methyl methacrylate-co-vinyl acetate) (P(MMA-VAc)). 1H NMR, FT-IR, DSC, TGA, XRD, SEM and AC impedance results revealed that when PMVIm-TFSI was added into polymer electrolytes consisting of P(MMA-VAc)/LiTFSI, the thermal stability and ionic conductivity improved significantly, the maximum of which is 4.71×10-4S?cm-1 at 30℃. Moreover, P(MMA-VAc)/PMVIm-TFSI/LiTFSI electrolyte membrane (transmittance≥90%) can be used as the ion-conductive layer material for electrochromic devices (ECDs), which revealed excellent electrochromic performance.
  • Research on Electric Heating property of new Carbon/ceramic Composite
    WEI Wei;XIA Jintong;LI Jin
    . 2011, 42(09): 1619-1622.
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    Abstract: The electric heating carbon/ceramic composites were prepared by blending, ball milling, 50Mpa die forming and 1000℃non-oxidizing sintering for 3h of raw materials, which include ceramic matrix of Bentonite and conductive components of flake graphite, pretreated graphite, black carbon and SiC as reinforced part. The phase and micromorphology of the carbon/ceramic composites were characterized and analyzed by XRD and SEM. The research of electrothermal property, mechanical property and antioxidation were carried on. Electric heating carbon/ceramic composites prepared possess superior electric heating property, which showed a rapid increase and then a relative stability in temperature only at a low voltage of 10V.The best performing one could rise to 643℃.By modifying content of SiC, flexural strength of the composite could reach to 14.3MPa. By combining carbon materials and ceramic materials, oxidation-resistance of carbon materials can be improved effectively for rasing the weight losing temperature of 200℃.
  • The formation conditions of perovskite-type LaCoO3 with different preparation method
    WANG Guangjian;LIU Dunqiang;BING Liancheng
    . 2011, 42(09): 1627-1630.
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    Two combustion synthesis methods, the coprecipitation method and sol-gel process, have been used to prepare complex oxide desulphurization catalyst of LaCoO3. The microscopic structure, catalytic specific surface, crystal formation of the perovskite oxides are analyzed and characterized by BET, XRD, SEM, TG-DTA. Higher surface area and more pure LaCoO3 samples could be achieved under following conditions: coprecipitation method, 12 h, 900 ℃; sol-gel process, 4 h, 800 ℃ and burning temperature of dried gel, 180 ℃.
  • The preparation and characterization of CMCS-coated VE liposome
    DANG Qifeng;LIU Chengsheng;YAN Jingquan
    . 2011, 42(09): 1631-1634.
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    In the present work, we report the synthesis of Carboxymethyl chitosan(CMCS) and the preparation of CMCS-coated VE liposome. TEM images of the CMCS-coated VE liposome showed that the particles were spherical and well separated. The influences of the CMCS concentration were not obvious to the zeta potential and average particle size of the CMCS-coated VE liposome. The conserving rate of the liposome increased and sedimentation volume rate decreased with the increasing CMCS concentration. The results indicated that the coating of the CMCS enhanced the storage stability of the VE liposome effectively.
  • Effects of carbonization temperature on properties of layered structural pantograph slide plate
    LU Wenbo;WANG Chengguo;YUAN Hua
    . 2011, 42(09): 1635-1638.
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    The effects of carbonization temperature on properties of layered structural pantograph slide plates（LSPSP） were investigated. LSPSP were treated at 400℃, 600℃, 800℃ in nitrogen gas atmosphere. By testing density, heat resistance, electrical conductivity property, impact resistance and abrasive resistance of LSPSP, the effects of carbonization temperature on properties of LSPSP were investigated. The wear mechanism was discussed through examining and analyzing the worn surface with scanning electron microscope (SEM). The results show that the density decrease when carbonization temperature increase. When the temperature is over 600℃, the temperature resistance of the resin is greatly enhanced. The electrical conductivity increases after carbonization, but its impact strength and abrasive resistance decreases with the increase of carbonization temperature. The major wear mechanism of composite is adhesion wear at low carbonization temperature, while adhesion wear and abrasive wear are the major mechanism at high temperature. The LSPSP carbonized at 600℃ have good comprehensive performances. The performance testing indicators meet the TB/T 1842.2-2002 standards.
  • Preparation and Characterization of acrylics resin- Silicasol / isocyanate wood adhesive without formaldehyde
    LI Xuan;SHEN Yiding;LI Xiaorui
    . 2011, 42(09): 1639-1641.
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    With polyvinyl alcohol (PVA) as polymeric colloid stabilizer, a kind of surfactant-free copolystyrene-acrylat latex with good stable and excellent property was successfully synthesized by reacting styrene (St), butyl acrylate (BA), N-hydroxymethyl Acrylamide (NMA) and acrylic acid (AA). The copolystyrene-acrylat latex as the main agent, silicasol and isocyanate as cross-linking agent, a kind of wood adhesive without formaldehyde was synthesized by copolystyrene-acrylat latex, silicasol and isocyanate. At the same time, the factors affecting its synthetic condition were discussed, and the synthetic process was optimized. The results show that adhesive owns excellent property when ω(PVA)=8%，ω(AA)=8%，ω(NMA)=4%，n(BA)/n(St)=2:1，ω(Sil)=10%，ω(HDI)=8%. when the resin content is 250g/m2 on the application experiment, the plank bonding strength reaches 0.82Mpa and the static strength reaches 20.5 Mpa. The outcome conformed the national standards. And it was characterized by the method of IR and TG.
  • Effect of Calcination Temperature on Photocatalytic Properties of TiO2 Hollow Microspheres
    ZHANG Gaowen;AO Wei;YANG Ni
    . 2011, 42(09): 1642-1645.
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    TiO2 hollow microspheres were successfully prepared with mono-dispersed cationic polystyrene microspheres as template, titanium tetrabutoxide as precursors by sol-gel method. TiO2 hollow microspheres with different crystalline phases were produced at different calcination temperatures．The microstructure, phase composition and photocatalytic activity of the as-synthesized products were characterized by using TEM, SEM, FT-IR, XRD and UV-Vis DRS. The experimental results indicate that the TiO2 hollow microspheres with the average diameters of 1.23μm possess a thin shell (30nm). The crystallite dimension of anatase increases with the increasing of calcination temperature and appears mixed crystal structure at 700℃. The TiO2 hollow microspheres calcined at 500℃ exhibit better photocatalytic activity and stability for the decomposition of methyl orange (MO) in aqueous solution compare to P25.
  • Preparation and Properties of Nanoporous Polyimide Films With Low Dielectric Permittivity
    JIA Hongjuan;YIN Xunqian;ZHA Junwei
    . 2011, 42(09): 1646-1648.
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    ABSTRACT: SiO2/polyimide(PI) nanocomposite films with low dielectric permittivity with diamines of pyromellitic dianhydride (PMDA) and 4,4-oxydianiline (ODA) were successfully synthesized by a wet phase inversion process. Then removal of the silica cores of the nano- composite films by HF etching gives rise to the nanoporous of PI films. It is found that the dielectric permittivities of the porous films can be reduced from 3.54 of the pure PI to 3.05 (1kHz)by using 15 wt% pore-former (SiO2). The nanopores were characterized by transmission electron microscopy (TEM). The relationships between the structure of the films and the properties, including the dielectric permittivity , the heat resistance, the contact angles and the mechanical strength , were researched.
  • On-line monitoring the curing behaviors of hydroxyl-terminated polybutadiene/toluene diisocyanate system via ultrasonic wave
    ZHAO Jinchao;ZHANG Aiqing;LUO Zhihua
    . 2011, 42(09): 1649-1652.
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    A longitudinal ultrasonic transmission method was applied to on-line monitor the curing behaviors of hydroxyl-terminated polybutadiene/toluene diisocyanate (HTPB/TDI) system at different temperature, the velocities and attenuations of longitudinal waves were determined during the whole curing process, and the gelation, vitrification and cure off time were identified based on the longitudinal storage modulus and curing degree of the HTPB/TDI system. Compared to infrared spectroscopy method, the ultrasonic monitoring reveals the curing process more reasonably due to the combination of physical and chemical gelations through the variation of modulus, and it is more sensitive to monitor the curing behavior of HTPB/TDI system after vitrifying.
  • The preparation and photoelectric characteristic of MgZnO films
    WU Xiaopeng;FU Zhuxi
    . 2011, 42(09): 1653-1656.
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    A series of MgxZn1-xO thin films have been grown by radio frequency magnetron sputtering on Si (100) substrates and quartz substrates which used MgxZn1-xO target. The thin films were characterized with X-ray diffraction spectrum(XRD)，Electron Spectroscopy for Chemical Analysis(XPS)，transmission spectrum and photoconduction spectrum. The XRD result shown that, MgxZn1-xO thin films only has a high diffraction peak of (002) of the hexagonal structure and the diffraction peak angle shift to larger angle with x increased when x≤0.325. They have a mixed hexagonal and cubic phase for MgxZn1-xO films when x≥0.40. From XPS patens, we found that MgxZn1-xO thin films were single hexagonal structure when x was 0.325. From transmission spectrum, we can found that all the MgxZn1-xO thin films high transmittance. By the Calculation of the MgxZn1-xO thin films absorption edges, we found the band gap energy were enlarged with x increased when x≤0.325. When x≥0.40, the band gap energy were decreased with x increased. All the MgxZn1-xO thin films have high photoresponse in ultraviolet band. The inflexions of photocurrent response curves were shift to blue with x increased when x≤0.325, it shown that the band gap energy were enlarged with x increased. We also found that the band gap energy was 4.9 eV when x was 0.325; this gap energy was in the solar blind.
  • Surface and Interface Analysis of 9, 9′-bianthracene /SiO2 using AFM and XPS
    LI Jianfeng;SONG Qing;NIU Zhenchuan
    . 2011, 42(09): 1660-1662.
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    The 9, 9′-bianthracene was deposited on SiO2 with dry oxidation by vacuum evaporation. Its morphology is characterized by atomic force microscopy (AFM), and the electron states are investigated by X-ray photoelectron spectroscopy (XPS). Analysis shows unwell distributed and film quality of 9, 9′-bianthracene on SiO2 was very rough with many cracks and pores, which can lead to heavy absorption of gas molecules。The oxygen can only result from the diffusion of O in the SiO2 layer and of H2O and O2 molecules absorbed at the CuPc film surface. SiO2 layers produced by spurting technology are better than those produced by oxidation technology in OFET.
  • Effects of Sputtering Power on Composition and Structural Properties of CdZnTe Films
    ZENG Dongmei;ZHOU Hai;LU Yimin
    . 2011, 42(09): 1663-1665.
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    CdZnTe films were prepared by radio frequency (r.f.) magnetron sputtering from Cd0.9Zn0.1Te crystals target with different sputtering power (60-120 W). The effects of sputtering power on the composition and structural properties of CdZnTe films were studied. CZT has a cubic zinc-blende structure of main (111) peak. As the increase of the sputtering power, the deposition rate and crystallinity of the films increases. The Cd atomic composition was higher than the Te atomic composition at any sputtering power. This behavior may be explained by the preferential sputtering of cadmium atoms rather than tellurium atoms in Cd0.9Zn0.1Te crystal target.
  • Peroxidase-like activity of bioinorganic ferromagnetic nanoparticles
    HU Lili;MA Qiufeng;XIE Chunlan
    . 2011, 42(09): 1666-1668.
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  • Preparation of CdS-Pt/TiO2 composite photocatalyst by low temperature method and its performance for photocatalytic hydrogen evolution under visible light irradiation
    PENG Shaoqin;HUANG Yahui;AN Ran
    . 2011, 42(09): 1669-1672.
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    CdS-Pt/TiO2 composite photocatalyst was prepared using a variety of methods. The photocatalysts were characterized by X-ray diffraction, BET, and UV-vis absorption spectroscopic techniques. The photocatalytic activity of CdS-Pt/TiO2 composite under visible light (λ≥420nm) was evaluated by photocatalytic hydrogen evolution. It was found that the preparation method enormously influenced the activity of CdS-Pt/TiO2 composite. The CdS-Pt/TiO2 composite by low-crystalline CdS coupled with Pt/TiO2 has the highest activity and the apparent quantum yield amount was 6.95%.
  • Optimal Identification of Parameters at Hot Plastic Deformation for 7075 Aluminum Alloy Based on Processing Map
    QUAN Guozheng;WANG Yixin;CHEN Tao
    . 2011, 42(09): 1673-1677.
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    The hot deformation behaviors of 7075 aluminum alloy at the temperature range of 573 K ~ 723 K and strain rate range of 0.01 s-1~10 s-1 have been studied by using hot compressing testing on a Gleeble-1500 simulation, then the true stress-strain data collected resulted the performance of calculations for strain rate sensitivity (m-value), power dissipation efficiency (η-value) and instability parameter (ξ-value) under the different ture strain. The processing maps including strain of hot deformation of 7075 aluminum alloy was constructed according to three criterion of the above, and the microstructures of deformed specimens were observed as a evidence index. The regions of flow instabilities and optimum hot working condition are can be attained from the processing map and microstructure. The results show that the security domain mainly of hot working for 7075 aluminum alloy in the high temperature and low strain rate region, furthermore the power dissipation factor increase gradually with increasing strain; By the metallographic observations, the grain refinement by dynamic recrystallization under the stable deformation conditions, and bands of ?ow localization which have been associated with cracking under the unstable deformation conditions. The optimal working parameters identified by the processing maps including strain contribute to designing the the hot forming process of 7075 aluminum alloy forging without any defect.
  • Preparation and Characterization of Carbon Nanofibers Containing Fe
    REN Chongbin;WANG Jianbin;SU Jianfeng
    . 2011, 42(09): 1678-1681.
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    A mixture of polyacrylonitrile (PAN) and polyferrocenylmethoxylmethylsilanes (PFMMS) in N,N-dimethylformamide and tetrahydrofuran was electronspun into submicrometer fibers with a microphase-separated structure. The fiber precursors were stabilized, and then carbonized. The morphology, size and components of pyrolyzed fibers were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy (XPS).
  • Photochromic Property and Mechanism of a Viologen Film Containing Ferric Chloride
    CHAI Yue;HE Ni;LI Zhibin
    . 2011, 42(09): 1682-1685.
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    Photochromic viologen/polymer blended films exhibit obvious coloring when exposed to UV light. The bleaching process of the colored film, however, is rather slow. Bleaching can be promoted by addition of transition metal ions into the blended films. A photochromic film composed of Ferric Chloride and viologen/polyvinylpyrrolidone is prepared in this work. Ferric Chloride destroyed the radical cations from the photoreduced viologens in the film, and makes the color of the film lighter with increased bleaching rate. The color of the photochromic films gradually becomes deeper with increasing times of repeated coloring/bleaching cycles. The blended film with mole ratios of Ferric Chloride to viologen in 1:1 after three times of cycles showed deeper coloring can be deeply colored when exposed to UV light， and bleached to colorless after repeated cycles of coloring/bleaching. Bleaching of the blended film is adjustable by the concentration of Fe2+ and the temperature of bleaching. The results of XPS spectra indicate that there exist both Fe2+ and Fe3+ in the blended film after exposing to UV light. A mechanism for the photochromic process is proposed: Fe3+ abstracts electron from the radical cation of the photoreduced viologen and becomes the redued Fe2+ while the photoreduced viologen returns back to the colorless oxised state.
  • The preparation on micro/nano-particles of carbazole-chalcone derivatives and their aggregation-induced emission enhancement (AIEE)
    WU Lina;WANG Xiaomei;FAN Congbin
    . 2011, 42(09): 1686-1689.
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  • Porous Poly caprolactone3-D Scaffolds By ScCO2 Induced Phase Separation
    DING Zhaohong;LIU Zhijun;GUI Qiuyuan
    . 2011, 42(09): 1690-1693.
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    Abstract : 3-D porous scaffolds has an important role in tissue engineering. Supercritical CO2 (ScCO2) induced phase separation method was employed to produce porous poly caprolactone (PCL) 3-D scaffold, and the effects of process parameters on pore size and structure were also investigated. A self-designed experiment system was set up. Four solution concentrations (15,20,25and30wt.%), three CO2 pressures (10,12,and14MPa), and three temperatures (35,40and45℃) were examined using the system. The morphologies of the scaffolds were examined by scanning electronic microscope. Pore distribution and pore size of the scaffolds were measured using Image-Pro-Plus software. Porous PCL 3-D scaffolds with pore size range of 40-80μm were obtained. The results indicated that the pore size decreased as the solution concentration increased; while it also decreased as the temperature decreased. However, the change of CO2 pressure had no significant effect on pore size. The results were also explained qualitatively in terms of the thermodynamics calculations using ScCO2-AC-PCL ternary system.
  • The effect of un-round magnetic particle on magnetorheologic grease shear stress and its computational model
    HE Guotian;LIAO Changrong;WANG Ping
    . 2011, 42(09): 1694-1697.
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    magnetorheologic grease is another magnetorheologic intelligent material with great development after magnetorheologic liquid and elastomer. This paper …, constructed the shear stress model of non-magnetic particle This model simulated the relation between shearing yield stress and magnetic density when radius and side length are equal, and when the volume is the same, and simulated the shearing stress under zero field. The result indicates that when the volume is the same the shear stress of non-round magnetorheologic grease of magnetic particle is bigger round one, and shear stress decreases with contacting border length, however, it is always bigger than round magnetic particle. Even though under zero field, the shear stress of non-round magnetorheologic grease of magnetic particle is bigger round one, which demonstrates that round magnetorheologic liquid is not the best choice. Thus, the mechanism investigation on magnetorheologic grease of non-round magnetic particle is significant for the manufacturing and application of high performance magnetorheologic liquid.
  • Characteristic analysis of fluorene OLEDs material
    ZHENG Huajing;RUAN Zheng;JIANG Yadong
    . 2011, 42(09): 1698-1703.
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    OLEDs were fabricated with a novel fluorene derivative material BDHFLYDFLQ as a molecular probe, exciplex emission was observed in devices with emitting peak locates around 542 nm. However, OLEDs have low efficiency and brightness because of the existence of exciplex. In order to manipulate the strength of exciplex emission, thin layer of CBP was inserted into the interface of NPB/ BDHFLYDFLQ heterojunction. Light emission of exciplex was decreased once CBP was inserted, and emission of electroplex will occur when CBP 15 not thick enough. When the film thickness of CBP layer 15 increased, light emissions of exciplex and electroplex were both eliminated. Light emittied from the device with 6 nm CBP layer inserted into NPB/B DHFLYDFLQ interface only characteristic light from BDHFLYDFLQ excitons was observed, and this device had higher external quantum efficiency and lower turn-on voltage.
  • Design, synthesis and properties of a novel cyclometalated organic ligand containing porphyrin
    SONG Bin;REN Jun;YANG Peng
    . 2011, 42(09): 1704-1707.
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    Efficent aqueous-phase Aldol condensation, Adler condensation, Michael addition, Vilsmeier and Knoevenagel reaction were successfully employed to synthesize a new donor-π-acceptor (D-π-A) type C^N^N structure of the cyclometaled organic ligand: trans-4-[2-(5,10,15,20-Tetraphenylporphyrin-2-yl)-ethenyl]-N-{4-[(2-phenyl-6-pyridine)pyridium]tolyl}-pyridium bromine salt (abbreviated as TPPB), The compound was characterized by 1H-NMR, 13C-NMR and ESI–MS. Linear optical, thermostability and electrochemical properties of the novel ligand were investigated. The results showed that the target molecule had good solubility and fluorescence properties which were instructive explorations for pursuing new luminescent materials.
  • Electrical properties and structural stabilities of GDC/YSZ electrolyte multilayer with different number of modulation period
    JIANG Xuening;MENG Xin;MENG Xianqin
    . 2011, 42(09): 1708-1711.
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    GDC/YSZ electrolyte multilayers with the same modulation period and different period number have been synthesized on sapphire singe crystal substrate by reactive magnetron sputtering. Their structure, growth morphologies and electrical properties have been characterized by x-ray diffraction, atomic force microscopy and ac impedance measurement respectively. The results indicate that, the first layer on the substrate acts as a growth template for the multilayer; the first layer of GDC and YSZ results in random growth and (111) textures for the multilayers respectively. The multilayers undergo a roughing growth process leading to increasing roughness and grain sizes with increase in thickness. Electrical conductivities of the multilayers increase with more modulation periods (i.e. interfaces), while their activation energies remain almost the same (~1.3eV). After sintered at temperatures of 500-800℃, the GDC/YSZ multilayer proves to be structural stable, and its conductivities decrease slightly (decrease ratio <5%) probably due to increase of grain sizes during sintering.
  • Synthesis and Characterization of CdS Nanorods in Ionic liquids [BMIM][BF4]
    JIANG Da;SI Wei;WANG Yanjing
    . 2011, 42(09): 1712-1713.
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    CdS nanorods were synthesized in room temperature ionic liquid via chemical reduction under ambient conditions. XRD and TEM were used to characterize the structure of the CdS nanorods. The results indicate that the diameter and the length of the bone-like nanorods are about 30nm and 300nm respectively and the structure of the CdS nanorods were hexagonal phase. the one dimension CdS nanorods weie formed by dual role of ionic liquids and decylamine. So we conclude that the room temperature ionic liquid is not only used as reaction medium but also as finishing agent and guiding agent.
  • Synthesis and Adsorption Properties of Sulfhydryl-functionalization HS-Zr-Ce-SBA-15 Mesoporous Materials with Short Mesochannels
    YUAN Jinfang;LI Jiansheng;WANG Fang
    . 2011, 42(09): 1714-1718.
    Abstract ( ) Knowledge map Save
    Thiol-functionalized HS-Zr-Ce-SBA-15 (HS-ZCS) mesoporous materials with unique hexagonal platelet morphologies and short channels were synthesized by a Co-condensation method using 3-mercaptopropyltriethoxysilane (MPTS) as organic modifiers , tetraethyl orthosilicate (TEOS) as a silica source, zirconyl chloride and cerous nitrate as precursors, and pluronic P123 triblock copolymer as a structure directing agent. The as-synthesized materials were characterized by low-angle X-ray diffraction (LXRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetry (TG), and N2 adsorption/desorption isotherms. Characterization revealed that the functionalized HS-ZCS mesoporous materials have unique hexagonal platelet morphologies with short channels and they possess a highly ordered two-dimensional hexagonal mesoporous structure similar to conventional SBA-15. The uptake of rhodamine 6G onto the organic functionalized HS-ZCS and HS-SBA-15 were compared. The results demonstrate that HS-ZCS materials have higher adsorption rates and adsorption capacities compared with HS-SBA-15. The resultant HS-ZCS materials with short channels are superior to conventional SBA-15 in terms of fiber morphology facilitating molecular diffusion when used in adsorption, separation, and catalytic processes.
  • Fabrication of the YAG transparent ceramic by the SHS quick densification technique under ultra-high-gravity field
    GUO Shibin;YANG Zengchao;LIU Guanghua
    . 2011, 42(09): 1719-1721.
    Abstract ( ) Knowledge map Save
    The technique of combustion synthesis under ultra-high-gravity field which combines the self-propagating high-temperature synthesis and the ultra-high-gravity field is the novel preparation method for the ceramics. But the ceramics can not be dense completely by the gravity field. There are many loosen areas in the YAG ceramics with the relative density 85%. When a weight block places on the system of the combustion synthesis under ultra-high-gravity field, the whole dense production can be prepared quickly. The technique is named the SHS quick densification technique under ultra-high-gravity field. The whole dense YAG ceramic with the relative density 98% was prepared by this technique. The results show that the YAG ceramics are dense from the macro-photograph and the micro-pattern. The loose areas are disappeared, and the grains are refined.
  • Deposition of polycrystalline diamond films by a new type MPCVD reactor at high power density
    YU Shengwang;LI Xiaojing;ZHANG Sikai
    . 2011, 42(09): 1722-1726.
    Abstract ( ) Knowledge map Save
    Polycrystalline diamond films were grown by using H2-CH4 as the source gas in a new type microwave plasma CVD reactor with an input power of 5 kW, gas pressure of 100 torr and 200 torr and different methane concentrations. Optical emission spectroscopy was used to evaluate the concentrations of H atoms and carbon active groups in the plasma. The surface morphology, fracture morphology and the quality of the films were examined by using scanning electron microscope and raman spectrum. Experimental results show that the new type microwave plasma CVD reactor is able to form diamond films in the condition of high power density. The concentrations of H atoms and carbon active groups were obviously increased by enhancing the power density, and hence the deposition rates of diamond films will be increased while keeping the quality of the diamond films as well.
  • Effects of deformation ratios on the average grain sizes and coercivity of Hot-pressed/Die-upset Nanocomposite Nd9Fe84.5Co1B5.5 Magnets
    LIU Yanjun;PAN Jing;ZHANG Wenwang
    . 2011, 42(09): 1727-1730.
    Abstract ( ) Knowledge map Save
    Nanocomposite Nd9Fe84.5Co1B5.5 magnets were prepared by hot pressed/die-upset process. The effects of deformation ratios on the average grain sizes of hard and soft magnetic phases and the resulting changes of intergranular interaction and intrinsic coercivity in the magnets have been studied. The results show that the average grain sizes of hard and soft magnetic phases in the die-upset magnets at the deformation ratio of 54% are 61.0nm and 51.8nm respectively, approaching those (52.1nm and 54.0nm) in the hot-pressed ones. However they are greatly reduced to 19.23nm and 22.36nm respectively at the deformation ratio of 74%. Comprehending with the outstanding refinement of the average grain sizes in the mangnets, the intergranular interaction between hard and soft phase changes from magnetostatic-coupling interaction in controlling to exchange-coupling interaction in controlling, resulting in an enhancement of intrinsic coercivity with 64%.
  • Research on the absorbing properties of absorbing plates based on the hollow-sphere structure
    LI Baoyi;DUAN Yuping;LIU Shunhua
    . 2011, 42(09): 1731-1734.
    Abstract ( ) Knowledge map Save
    The absorbing properties of expanded polystyrene beads (EPS) coated with carbon black were studied. Absorbing mechanisms of hollow-spheres were discussed, which indicated that the losses by resonance and scattering play an important role. The attenuation loss and resonant frequency can be controlled by adjusting the thickness of conducting layer and sphere radius. Filling with EPS coated with carbon black, the absorbing properties of cement composites were improved greatly, especially in the low frequency range. Thus, it is promising to use EPS coated with carbon black as a kind of light, efficient absorber.
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