15 January 2012, Volume 43 Issue 01
    

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    研究与开发
  • Low temperature synthesis of different flowerlike ZnO by water bath method
    Zhen-Feng Zhu;Hua-Ni Lin;Zhi-Zhan Chen
    . 2012, 43(01): 1-5.
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    Flowerlike ZnO microcrystals with different rods have been successfully synthesized by a simple water bath route at 70?C. Zinc acetate was used as raw material, ammonia as regulating pH agent and PEG-2000 as the capping agent. The results showed that the as-grown ZnO microcrystals presented flowerlike structure with existing PEG-2000. The use of different quantities of ammonia with the precursor altered the top morphology of the ZnO from hexagonal rods to sword-like rods. X-ray diffraction analysis showed that the diffraction peak intensity ratio of (002) to (101) were quite different for different rods. Transmission electron microscopy observation indicated that the hexagonal rods are single crystalline in nature, while the sword-like rods are oriented polycrystalline structures. The room temperature photoluminescence spectra of ZnO with different rods showed typical peaks at ~380nm which corresponded to the near band-edge emission.
  • The Flame Retardancy Research of SiO2/Mg(OH)2 Composite
    Jie Pan;Bin Li;Zhao-Bo Wang;Fang-Lin Du
    . 2012, 43(01): 6-9.
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    A composite was prepared with SiO2/Mg(OH)2 powder and POE by melt-blending. The properties of the composite were studied by glow wire tester; the cross-section morphology and the interfacial compatibility were investigated by SEM; and the dispersion in the matrix was characterized by EDS. The mechanical properties of SiO2/Mg(OH)2/POE were also studied. The results showed that SiO2/Mg(OH)2 composite flame retardants were of good dispersion and interfacial compatibility, excellent flame retardancy; the mechanical properties of polymer materials could be well improved. Thus, SiO2/Mg(OH)2 is a new inorganic material that was suitable for popularization.
  • Effect of Additive on Properties of Polyimide Liquid Crystal Vertical Alignment Film
    Zi-Jun Deng;Ming Liu; Ying-Han Wang
    . 2012, 43(01): 10-13.
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    Abstract:The effect of polyimide (PI) structure and preparing condition on properties of alignment film has been reported widely, but to our knowledge, the effect of additive on alignment film has not been explored. In this paper, the effect of the additive on alignment property, rubbing-resistance, thermal stabilities and transmittance of PI was investigated. The PI alignment film was prepared by pyromellitic dianhydride (PMDA), p-Phenylenediamine (PDA) and 4- hexyloxy -bip henyl-3′,5′2-diaminobenzoate (C6-BBDA). The PI was modified by the additive (end capping agent and crosslinking agent). The structures and properties of PI were measured with infrared spectrometer (FT-IR), thermogravimetric analysis (TGA), ultra-visible spectrometer, polarized microscopy and pretilt angle tester. It was found that uniform LC vertical alignment was induced by four kinds of PI films. PI film modified with crosslinking agent showed excellent rubbing-resistance and still kept LC vertical alignment after strong rubbing in rubbing strength as 600mm. PI films with the additives possessed good thermal stabilities. Moreover, PI films with the additives had high transmittance.
  • Fabrication and Spectral properties of Ceramic cenospheres coated with Cu
    Cheng-Wu Fu;Shuan-Qin Zhang;Jun-Fang Meng;Chen-Ming Qing
    . 2012, 43(01): 14-16.
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    Chemical plating method was used to fabricate ceramic cenospheres coated with Cu in this paper. SEM, XRD and EDS were applied to analyze the morphology and the state of the coated ceramic cenospheres, and the optimum volume concentration of reductant was determined. The 1.06μm and 10.6μm laser reflectivity were measured by Infrared Spectrometer, CO2 Laser scanner and Energy meter. With increasing the CuSO4 concentration, the 1.06μm and 10.6μm laser reflectivity decreased correspondingly.
  • Experiment on the Radar Stealth Effect of Blended Materials for Cement based Materials
    Wei-Hong Xie
    . 2012, 43(01): 17-20.
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    By using more extensive application of current international evaluation method Measuring experiment by arch method ,taking cement as matrix, blending material silica fume and culver zed fuel ash, graphite and carbon fibers, nano-TiO2 and steel fibers for absorbing agent trial Sample, in the 8 ~ 18 GHz frequency band within the absorbing performance is analyzed, the experiment results indicate that silica fume and culver zed fly ash, nano-TiO2 and steel fiber and composite cement which made of Absorbing material has good absorbing performance, in the 8~18 GHz test frequency band, the more content of blending material increased, the better absorbing efficiency performance, but there is a limit. Graphite and carbon fiber and cement composite made of the effectiveness of absorbing materials when the graphite and carbon fiber fraction is 6wt% above, absorbing properties of composites will decline. Silica fume and culver zed fly ash mixture of the best content is 30wt%, while the best content of nano-TiO2 and steel fiber is nano-TiO2 4 vol%, and 4wt% steel fiber. Studied results showed that there's a comprehensible comparative analysis carried out on the basis hot a large number of experimental data obtained . increased blending materials led the composite's dielectric constant and magnetic permeability decreased, and the material itself, the loss of performance degradation. When blending material exceeding a certain threshold, enhance its ability of wave-transparent enhance while absorbing performance will be reduced.
  • Simulation of thin film growth in organic vapor phase deposition
    Guo-Dong Li
    . 2012, 43(01): 21-23.
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    The transport regime in OVPD system was briefly described by modeling the transport process. The simulation of dynamical deposition of organic vapor through apertures employing monte carlo method shows that the deposition pattern shape was affected by the process parameters such as molecular mean free path (deposition pressure), the aperture geometry and the mask-to-substrate separation. The simulation discussed here indicates that a high pattern definition could be achieved by reducing the space of mask-to-substrate and by decreasing the deposition pressure. The using efficiency of materials could be improved by using a thinner mask.
  • Preparation and characterization of Yb3+，Er3+ and Eu3+-codoped TiO2 nanobelts
    Li Li;Jing-Guo Lei;Tian-Hao Ji
    . 2012, 43(01): 24-27.
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    Yb3+, Er3+ and Eu3+-codoped anatase TiO2 nanobelts were obtained simply through two-step exchangeable and hydrothermal processes. Such tri-cation-doping has not damaged TiO2 structure and morphology yet. The optical measurement results show that as rare earth doping concentration is low, the positions of up-converted emission peaks arised from Yb3+ and Er3+ co-dopants, whereas the luminescent emission peak of Er3+ dopants can be observed due to the excitation of up-conversion emission, and simultaneously, the down-conversed emissions of Eu dopants are not affected by Yb3+ and Er3+ co-dopants. The investigation of the up-conversion emissions of the rare-earth-doped products demonstrates that such emissions are two-phonon processes, which are markedly influenced by TiO2 matrix and Eu-doping.
  • Preparation and Photocatalytic Activities of Cu2O-WO3 Composites
    Ji-Mein Song;Hong Wang;Xiao-Xia Zhang
    . 2012, 43(01): 28-30.
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    Cuprous oxide (Cu2O) microcubes and Cu2O-WO3 composites have been successfully fabricated by solution-phase reducing method at room temperature. The samples were characterized by X-ray powder diffractometer (XRD), field emission scanning electron microscopy (FESEM). The decoloration rate of dyes for the as-synthesized Cu2O microcubes as photocatalyst were examined at different conditions. The results showed that the decoloration rate of anion dyes were higher and that of cation dyes were lower. The photocatalytic activities of the as-synthesized Cu2O-WO3 composites were studied by monitoring the degradation of cation dyes (methylene blue) solution. It was found that photocatalytic activities of the as-synthesized Cu2O-WO3 composites were more superior than Cu2O microcubes. The decoloration rate of methylene blue was reached 61.8% for 10% Cu2O-WO3. Moreover, the photoluminescence properties of the products were investigated. The photocatalytic degradation mechanism for the composite as photocatalyst was proposed.
  • Synthesis and Characterization of α-Ni(OH)2 and NiO with flowerlike hierarchical architectures
    Chang-Yu Li;Shou-Xin Liu
    . 2012, 43(01): 31-35.
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    α-nickel hydroxide (Ni(OH)2) with flowerlike hierarchical architectures was successfully synthesized, using urea and Ni(NO3)2 as the starting materials .The prepared products were characterized by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TG) and N2 dsorption-desorption. According the results, the prepared Ni(OH)2 was typical α-phase with specific surface area of 245.0 m2/g and showed flowerlike structure with 4-6 um in diameter. Flowerlike nickel oxide (NiO) with the similar flowerlike and the pecific surface area of NiO was 125.2 m2/g.
  • Wear and Corrosion Behavior of Ti-Matrix Functional Gradient Layer
    Fang-You Hu
    . 2012, 43(01): 36-38.
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    To improve the wear and corrosion resistance of Ti600, and alleviate thermal stress as well under hyperthermal and excessive temperature difference condition, experiments of Ti-matrix FGL on Ti600 substrate by pulsed Nd:YAG had been carried out. The microstructures and phase composition of FGL were investigated. The friction wear and corrosion properties of FGL, N-FGM and Ti600 substrate were examined. It was found that a rapidly solidied microstructure consisting of in situ synthesized TiC reinforced phase distributed on FGL substance evenly and dispersely in the form of globular grains had three main different shapes:bulky or imperfect arborescent crystal, fine or approximately equiaxial crystal and chopped fibriform crystal. The wear and corrosion resistance of FGL was improved. Friction coefficient and wear rate decreased significantly, 0.3-0.5 times of Ti600 substrate. Corrosion current and resistance were 0.72 and 1.31 times of Ti600 substrate separately.
  • The cushion model and its application of C-flute corrugated paperboard
    Fu-de Lu;De Gao
    . 2012, 43(01): 39-41.
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    Basing on universal testing machine and drop testing machine, the cushion theoretical model of C-flute corrugated paperboard is established and the parameters of the model are identified by using least square method. The given example of cushion packaging dynamic shows the constitutive model can be used to packaging design, and this method is better than the maximum acceleration-static stress curves that need more test and data in designing cushioning packaging.
  • Effect of zinc lactate nano-wires as nucleating agent on the crystallization of poly(lactic acid)
    Ping Song
    . 2012, 43(01): 42-45.
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    Abstract: Effects of zinc lactate (ZL) and zinc lactate nano-wires (ZLNW) on the crystallization behavior, melting behavior, crystalline structure and morphology of poly(lactic acid) were investigated contrastively by means of differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and polarizing optical microscopy (POM). The results showed that zinc lactate nano-wires was a more effective nucleating agent in comparison to normal zinc lactate, supplied more activated nuclei for the crystallization of poly(lactic acid), played a role in heterogeneous nucleation, enhanced the crystallization temperature, degree of crystallinity and crystallization rate, additionally, the spherulites became smaller and more homogeneous. The crystal growth manner, crystalline structure and crystal form of poly(lactic acid) were not changed with the incorporation of zinc lactate and zinc lactate nano-wires.
  • Research on catalytic graphitization progress of C/C-SiC composite by compression moulding
    Ming-Yu Zhang;Dong Huang;Zhe-An Su
    . 2012, 43(01): 46-49.
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    Compression moulding of short carbon fiber and resin, liquid resin impregnation and pyrolysis was included in C/C-SiC composites fabrication. Firstly, the analysis on graphitization shows carbon-silicon reaction enhanced Si activation to B and its graphitization rises from 87.9% to 97.3%. Investigation of morphologies and gradients shows graphitization occurred with carbon-silicon reaction. SiC shows uniform distribution inside materials. Secondly, boron-catalytic graphitization is discussed. With mass fractions of boracic formaldehyde-phenol resin，decreased from 69.9% to 46.3%, the graphitization degrees reduce from 91.6% to 70.4%. Finally, catalytic graphitization mechanism of Si is put forward. As contents of Si rises from 0% to 6.3%, graphitization degree of composites rises from 78.1% to 90.7%.
  • Hydrothermal Synthesis and Photocatalytic Property of CaTiO3 assisted with Sodium Citrate
    Wei Zheng;Xiao Wei;Zhao-Hui Ren
    . 2012, 43(01): 50-53.
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    Calcium titanate (CaTiO3) nanocrystals were successfully synthesized by using titanium oxide hydroxyl which is the hydrolysis precipitation of tetrabutyl titanate ((C8H9O)4Ti), calcium nitrate (Ca(NO3)2?4H2O) and potassium hydroxide (KOH) as mineralizer and sodium citrate as complexing agent via hydrothermal reaction route at 200℃ for 12h. The morphology, crystalline size and phase formation of the synthesized powders were investigated using SEM, XRD and TEM. The photocatalytic activity was studied through recording the degradation of rhodamine B (RhB) in UV. Sodium citrate must be playing a key role in the hydrothermal synthesis of CaTiO3 nanaocrystals. The morphology and photocatalytic activity of samples vary with the concentration of sodium citrate.
  • PID Control and Controller Gains Optimization of Hysteretic Systems of SMA Actuator
    Wang-Zhong Liu;Zhao-Bo Chen;Shan-Yun Huang
    . 2012, 43(01): 54-58.
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    Shape memory alloy is a new functional materials, which was popular with many applications in various fields as a result of good candidate to be excellent electrothermal actuator. However, the inherent nonlinearity and hysteresis occered in material that pose a challenge in the design of control system and thermomechanical modeling that is of significant importance in implementing a simple controller strategy and realtime control. In this paper, a hysteretic mode1 relating the displacement to the temperature of SMA wire based on Preisach theory is presented, the fundamentals on the thermal transfer in actuator is explored, and then the traditional proportional-integral-differential control is idealed to this nonlineaer system with the optimizing parameters by the huristic algorithm like swarm particle and ant colony strategy. Compared to the conventional method regulating the PID parameters, the intelligent algorithms optimizing the controllers can track the step signal and sinsoidal input better, and is stronger in real time, overcoming the nonlinearity and hysteresis in the actuator system.
  • Synthesis and Characterization of ZnS:Fe nanocrystals by micro-emulsions method
    Li-Hua Li;Rui-Shi Xie;Jin-Quan Xiao
    . 2012, 43(01): 59-61.
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    Abstract：ZnS: Fe nanocrystals were synthesized in W/O micro-emulsions by using Span 80/Tween 80/cyclohexane/water systems. The crystalline, microscopy and luminescent properties of ZnS:Cr nanocrystals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence (PL) spectra. The results show that ZnS:Fe nanocrystals have cubic zinc blende crystal structure, and the size of these spherical particles is 3nm. From PL spectra of ZnS: Fe nanocrystals in micro-emulsion with different doping concentrations of Fe ion, the intensity of the emission peaks in ZnS: Fe(1%) nanocrystals was found the strongest, indicating that doping concentration has a great influence on the luminescence properties of ZnS substrate. In addition, the fluorescence decay curves of the ZnS: Fe nanocrystals were tested, and the calculated fluorescence lifetime of the ZnS: Fe nanocrystal was 3.07 ns.
  • Preparation of ZnS-CdS composite nanoparticles by sulfuration of a double hydroxide precursor and its photocatalytic performance
    Zhao-Di Xu;Yue-Xiang Li;Shao-Qin Peng
    . 2012, 43(01): 62-65.
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    Abstract: ZnS-CdS composite nanoparticles with different Zn/Cd molar ratios were prepared by sulfuration of a double hydroxide precursor. The crystal structure and composition of the obtained products were investigated by XRD. The optical absorption properties of the products were characterized by UV-Vis DRS. Using the SO32-/S2- as electron donor and Pt as a cocatalyst, hydrogen evolution of the products prepared under different conditions (preparation method, Zn/Cd molar ratio and reaction temperature) was studied under visible light (λ≥420 nm). The product ZnS-CdS-2:1, which was synthesized by means of mixture of cadmium sulfate and zinc sulphate first coprecipitated with NaOH solution, following sulfuration with S2-, had the highest photoactivity and good stability.
  • Effect of the Crystallization Treatment of Bioactive Borate-Based Glass Containing Strontium on its degradation and Bio-activity in vitro
    Lin-Lan Lu;Jian Lin;Yi-Fei Gu
    . 2012, 43(01): 66-68.
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    For the research of the effect of crystallization treatment on bioactivity in vitro and degradability (dissolution) of borate-based glasses containing strontium, particle samples with different strontium contents were prepared by a melting process(Sr=0, 2, 6 mol%) and then heat-treated at 700 oC for 4 hours. After immersed in a 0.02M K2HPO4 solution (a similar solution to simulation body fluid solution, SBF) at 37oC with a given period of time, with the ratio of 1g glass powder corresponding 100 ml solution, each group of samples both before and after crystallization were characterized by mass loss analysis, pH value measurement of the solution, and their immersion products were analyzed by X-ray diffraction and FTIR. The results show that the samples both before and after crystallization can convert into the strontium- contained hydroxylaptite, showing the virtro bioactivity, and that the ion leach rate from the samples can be slow down after crystallization, thus reducing the high degradability rate of the borate-based glasses, that can be matched with the bone growth rate. Therefore, the biodegradability rate of the samples can be adjusted by the crystallization of borate-based glasses and this kind of crystallized glass would be found their clinic application in bone repair.
  • Fabrication of Ordered Porous Films of Urushiol Copper Polymers by Breath Figures
    Zhen Luo;;Yan-Lian Xu;Jin-Huo Lin
    . 2012, 43(01): 69-72.
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    Ordered porous films have received great interest in the past few years because of their potential application in functional membrane, biological materials and medical science. Even though lots of lithographic techniques were used to prepare ordered porous materials, the expensive cost limited its wide range of application. However, the so-called breath figures approach which had the inexpensive and simple process attracted researchers’ attention. To prepare the porous films with excellent thermal stability and corrosion resistance, urushiol metal polymers, which contained the superior heat resistance and chemical resistance, were employed in the work. High ordered porous films were successfully prepared via the breath figures method making use of the urushiol copper polymers (UCP). The effects of solvents, the relative humidity and the moist airflow speed on the morphology of the porous films were investigated, and then the product was characterized by SEM and IR. The results showed that the honeycomb-structure porous films could be obtained by taking carbon disulfide as solvent in the static state (the relative humidity: 95%) or in the gas flow rate of 400 ml/min (the relative humidity: 85%). And they had good hydrophobicity, excellent chemical resistance and thermal stability. Furthermore, the pore size was about 1.5μm under 95% relative humidity and 0.85μm under 85% relative humidity.
  • Synthesis of amphiphilic graft copolymers in supercritical carbon dioxide and hydrophilicity modi?cation of poly(vinylidene fluoride) membranes
    Jian-Hua Wang
    . 2012, 43(01): 73-76.
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    In this work, supercritical carbon dioxide (SCCO2) was used as reaction medium, amphiphilic graft copolymers composed of poly(styrene-alt-maleic anhydride) (SMA) backbones and methoxyl poly(ethylene glycol) (MPEG) side chains were successfully synthesized in solid state. The structure and characteristic of the graft copolymers were investigated by 1H NMR and FT-IRT respectively. Then, the copolymers were used as hydrophilic additives in the preparation of composite poly(vinylidene fluoride)(PVDF) membranes via phase inversion process. The membranes were characterized by SEM, XPS, water contact angle and BSA static absorb experiment.The blend membranes exhibited higher hydrophilicity and anti-fouling property.
  • The wetting and interface reaction mechanism of Ag-Cu-O brazes on BaCo0.7Fe0.2Nb0.1O3-δ oxygen-permeable membrane ceramic
    Qi-Fei Zhang;Yu-Wen Zhang;Li-Juan Hou
    . 2012, 43(01): 77-80.
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    The wetting and interface reaction mechanism of Ag-Cu-O brazes on BaCo0.7Fe0.2Nb0.1O3-δ（BCFNO）oxygen-permeable membrane ceramic were investigated by the sessile drop wetting experiment and SEM/EDS test. The results indicate that the wetting of Ag-Cu-O brazes on BCFNO follow the wetting mechanism of interface reaction, with the Cu content and temperature increased, wetting angle rapid decreased. When the content of Cu was 3.3(mol %), in BCFNO side at the interface a layer of reactive layer was generated. The existence of reactive layer reduced the liquid-solid interfacial energies, then improved the wettability of interface and enhanced the mutual metallurgy effect. Reactive layer are caused by the interface reaction (CuOx + BaCoFeNbO→Ba-Cu-O + Co-Cu-O) occurs in the interface. The complex oxide Ba-Cu-O, Co-Cu-O in the grain boundary of BCFNO matrix show island shape distributed.
  • Preparation and Electrochemical Capacitive Properties of Co3O4-NiO composite particles modified by ethylenediamine
    Hui Xu
    . 2012, 43(01): 81-83.
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    Ni(OH)2-Co(OH)2 was obtained by an easy simple liquid coprecipitation method. After calcination, the Co3O4-NiO composite particles were gotten, then modified by ethylenediamine. And the dispersion of Co3O4-NiO particles improved, morphology was flake, it formed loose mesoporous structure among each particles. Meanwhile, electrochemical supercapacitors properties of Co3O4-NiO electrode material were tested. The consequence manifested that the Co3O4-NiO composite particles showed excellent electrochemical performance and its single electrode specific capacitance was up to 1202F/g at the potential window of 0-0.4V, which increased 171F/g compared with the unmodified.
  • Thermal performance of high melting points paraffin emulsions for latent heat transportation
    De-Qiu Zhou;Rui Xiao;Zi-Ping Feng
    . 2012, 43(01): 84-87.
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    To match the temperature range of central heating systems, several types of commercial grade paraffin with melting points have been investigated as the candidate phase change material (PCM). And the thermal behavior of the paraffin was tested. According to the phase change temperature difference and heat of fusion, the paraffin with the melting point at 87 ℃, latent heat of 203.9J/g, phase change temperature range of 80-90℃ was selected as the best phase change material. Paraffin emulsions were prepared by mixing non-ionic surfactants and co-surfactants. Thermal physical properties of these paraffin emulsions such as phase transition temperature and latent heat were tested. Because paraffin emulsions can store their latent heat during phase change process in the temperature range of 80-90 ℃, their heat storage density their and heat carrier density are higher than water. Based on that, paraffin emulsions are suitable for latent heat transportation.
  • Preparation and rheological property of 2-hydroxy-3-butoxypropyl guar gum
    Xue-Xiao Jia;Yi-ding Shen;Xiao-Juan Lai
    . 2012, 43(01): 88-91.
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    2-hydroxy-3-butoxypropyl guar gum(HBPG) was synthesized with guar gum(GG) as material, using n-butyl glycidyl ether(BGE) as the hydrophobic reagent, sodium hydroxide as catalyst and isopropanol as solvent. The structure of HBPG was characterized by means of FT-IR、XRD and TGA, meanwhile, the rheological property of the aqueous solution and the gel of HBPG were discussed. The results showed that the hydrophobic modification can reduce the crystallinity and improve the thermal stability. Compared to GG, HBPG has better thickening property and the solution stability has significantly improved. The rheological property of the gel of HBPG was better than GG. The gel of HBPG has good temperature resistance and shear stability properties.
  • Preparation and Properties on Rare-earth element Cerium Doped Nano-Titanium Dioxide Photocatalyst
    Ning-Ning Yan;;;;Ying Zhang;Chang-Jie Gong;Qing-Ju LIU
    . 2012, 43(01): 92-95.
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    The nano-TiO2 doped with Ce was prepared by sol-gel method. The samples were analyzed by X-ray diffraction(XRD), FT-IR, UV-Vis, PL, Nano-sizer Nano Particle Size Analyzer, et al. The photocatalytic activity of Ce-TiO2 was investigated at different doping dosage and different calcinated temperatures by measuring the degradation rate of methyl blue(MB) under the irradiation of fluorescent lamp, the results show that crystal phase of Ce-TiO2 samples are all mixed phase of anatase and rutile. The existence of the doped element Ce expands TiO2’s spectrum absorption under the visible light, and increases the photocatalytic activity of TiO2. Meanwhile, the photocatalytic activity of the sample at pH=1.5, Ce:TiO2 =1:300(molar ratio) and the calcinated temperature of 600℃ is the best, and it is obvious higher than that of P25.
  • Preparation and Investigation of Magnetic Properities of Amorphous Fe78Si9B13 Powder Core
    Jian Tang;Fa-Zeng Lian;Min Yu
    . 2012, 43(01): 96-98.
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    Amorphous magnetic powder cores were fabricated from the amorphous Fe78Si9B13 alloy powder prepared by jet milling. The effects of annealing temperature and forming pressure on the performance of the core were investigated. The results show that when the annealing temperature is below the initial crystallization temperature of the alloy powder, the loss of the core first decrease and then increase with the increasing of annealing temperature, opposite to permeability and reach their peak value when the annealing temperature is around 350℃. The forming pressure increases lead to magnetic powder core density increased, while decreased the core loss and increased the permeability. When the pressure is around 2000MPa, they achieve their maximum.
  • Compression deformation behavior of 30%Mo/Cu-Al2O3 composite at elevated temperature
    Yong-Wei Sun;Yong Liu;Bao-Hong Tian
    . 2012, 43(01): 99-102.
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    Using the Gleeble-1500D thermal simulator, the high-temperature plastic deformation behavior and processing map of 30%Mo/Cu-Al2O3 composite are investigated at 450~750℃ with the strain rate of 0.01~5s-1 and total strain of 0.7. The results show that the softening mechanism of dynamic recrystallization is a feature of high-temperature flow stress-strain curves of 30%Mo/Cu-Al2O3 composite, and the peak stress increases with the decreased deformation temperature or the increased strain rate. Based on the true stress-strain curves, the established constitutive equation represents the high-temperature flow behavior of 30%Mo/Cu-Al2O3 composite, and the calculated results of the flow stress are in good agreement with the experimental results of the high-temperature deformation. Meanwhile, the obtained processing map of Dynamic Material Modeling is used to analyze the deformation mechanism and the destabilization mechanism of 30%Mo/Cu-Al2O3 composite, the optimal deformation processing parameters of the deformation temperatures rang and the strain rates rang are 650~750℃, and 0.01~0.1s-1, respectively.
  • Alignment of single-walled carbon nanotubes strands
    Dan-Na Yang;Lin Wang;Xiao-Xian Zhang
    . 2012, 43(01): 103-107.
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    Fluidic assembly method is a simple and effective way to align the single-walled carbon nanotubes (SWNTs). In this paper, we applied fluidic assembly technique to successfully align SWNTs on the parallel patterns substrate with different wettabilities. SWNTs suspension was droped into photo-resist resin mircochannels, and the shear force of solvent evaporation could stretch and align SWNTs into strands with nanoscale width in the mirochannels. Then these aligned SWNT patterns were successfully transferred to a pair of gold electrodes with different gaps to fabricate carbon nanotube field effect transistor (CNTFET). The electrical performance of CNTFET) fabricated by this technique was evaluated. The result indicated that the SWNTs strands could bridge different gaps to fabricate CNTFETs with good performance.
  • Biosorption Behavior of Dead Baker’s Yeast to Sr2+ and Its Effect by γ-ray Radiation
    Qun-Wei Dai;Fa-Qin Dong;Wei Zhang
    . 2012, 43(01): 108-111.
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  • UV grafting modification of Li-ion battery separator
    Xiao-Yuan Lv;Hua Li;Zhi-Qiang Zhang
    . 2012, 43(01): 112-115.
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    The ultraviolet irradiation method was used to graft methyl acrylate (MA) to Li-ion battery separator. It was found that the degree of grafting (DG) was influenced by initiator concentration, monomer concentration and irradiation time. The MA-graft-separator was analyzed by FT-IR、SEM and contact angle testing. With BP concentration of 0.02g/ml, pure MA monomer solution and irradiation time of 90s, DG was 68.9%, and the wetting ability improved obviously with the contact angle reduced to 12°from 46°.
  • Influence of Impregnating time on Oxidation resistance of Carbon/carbon Composites modified by a Solvothermal Process
    Jia Zhu;Jian-Feng Huang;Li-Yun Cao
    . 2012, 43(01): 116-119.
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    Carbon/carbon (C/C) composites were modified by a sol-gel integrated with solvothermal process using Tributyl borate sol and B2O3 micro powders. The as-modified C/C composites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) techniques. The influences of the solvothermal treatment time on the phase, microstructures and anti-oxidation properties of the modified C/C composites were investigated. Results show that the surface of the C/C composites is covered by a B2O3 protective layer; meanwhile, the internal defects of the matrices are occupied by B2O3 after modification. The density and smoothness of the layer are improved when the temperature range from 12h to 72h, moreover, the oxidation resistance of the C/C composites is effectively improved. The anti-oxidation property of the modified C/C composites is improved with the increasing of solvothermal time. The mass loss of the modified C/C composites is only 2.13% after oxidized in air at 600°C for 17h.
  • Preparation of Ag/cubic textured Cu composite tapes for coated conductor
    Feng-Hua Li;Lei Pang;Qing-Wei Luo
    . 2012, 43(01): 120-122.
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    Cubic textured Cu tapes were prepared by cold rolling twice combined 850℃ post heat treatment. Uniform Ag films were deposited on cubic textured Cu tapes by electroless plating with silver nitrate, sodium sulfite and sodium thiosulfate as the main raw materials. Ag films retained (200) preferred orientation when heated to 600℃ holding for 30min. But when the temperature was raised to 830℃, Ag films spreaded to Cu substrates. Only after repeated electroless plating silver and 830℃ heat treatment five times, Ag films showed (200) preferred orientation and a small amount of in-plane texture. The final Ag/cubic textured Cu composite tapes can be metallic substrates of the second generation high temperature tapes YBCO coated conductor.
  • Speedy synthesis of β-SiC and the investigation on supported Pd catalyst
    Hui-Yun Hong
    . 2012, 43(01): 123-125.
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    Silicon carbide (SiC) with a surface area of 159m2/g was speedy synthesized by a simple sol-gel process and carbothermal reduction method. In this method, the cheap sodium silicate and sucrose were used as silicon resource and carbon resource, respectively. Meanwhile, HCl was used as acidity regulator while H2SO4 acted as catalyst. Then the Pd/SiC catalyst was prepared by incipient impregnation for the investigation of oxidation on CO and C3H6. The result showed that the catalyst loaded 0.45wt.% Pd exhibited relatively high catalyst activity, and the lowest complete conversion temperature of CO was 230℃ and C3H6 was 235℃.
  • Effect of nonstoichiometry on the phase transitions and properties of (K0.465Na0.465Li0.07)(Nb0.95Sb0.05)O3 lead-free piezoelectric ceramics
    Wen-Feng Liang;Wen-Juan Wu;Ding-Jin Xiao
    . 2012, 43(01): 126-129.
    Abstract ( ) Download PDF ( ) Knowledge map Save
    The (K0.465+xNa0.465+yLi0.07)(Nb0.95-zSb0.05)O3 (with x, y, and z varying from -0.01 to 0.02) ceramics were prepared by conventional technique and the effect of nonstoichiometry on the phase transitions and piezoelectric properties of the ceramics were studied. The results reveal that the ceramics with stoichiometric composition have perovskite structure with tetragonal phase; the excess or deficiency of K or Nb component cannot change the symmetry of the ceramics in experimental composition range, however, the excess of Na component will lead to the increase of TO-T of the ceramics above room temperature and the TO-T increase with y in the range concerned; the volatilization loss of the alkaline K or Na can be compensated by adding ~0.5 % mol of K or Na content and enhanced piezoelectric properties are obtained; and the ceramics still have such promising piezoelectric properties d33>200 pC/N and kP>40% even with composition deviation from designed one (x =0~0.02 when y=z=0, y =0~0.01 when x=z=0, and z =-0.01~0.005 when x=y=0). These results are much favorable for the experimental work and/or for the mass production when the materials are adopted for devices applications.
  • Aligned Porous Conductive Carbon Black/Polyvinyl Alcohol Composite Obtained by Directional Freeze-drying
    Hong He;Ding-Fei Zhang;Xiang-Bin Xu;Hong Chen
    . 2012, 43(01): 130-132.
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    Aligned porous conductive Carbon Black (CB) /Polyvinyl Alcohol (PVA) composite is obtained through directional freeze-drying process in this paper. The result shows that the conductive property of CB/PVA composite does not obeys the universal percolation theory. The value of critical resistance exponent is not in the range predicted by the universal percolation theory. The nonrandomly distribution of CB in PVA matrix and the special aligned porous structure leads to the high value of resistance exponent.
  • Preparation and Characterization of Poly(N,N-diethyl acrylamide)-g-Polyacrylonitrile/Polystyrene Microspheres with Thermosensitivity
    Jing Sui;Ming-Qing Chen
    . 2012, 43(01): 133-136.
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    Poly(N,N-diethylacrylamide) with a terminal hydroxyl end group (PDEAm-OH) was synthesized by radical polymerization in the presence of 2-mercaptoethanol (ME). Thermosensitive poly(N,N-diethylacrylamide) (PDEAm) macromonomer was prepared by condensation reaction of PDEAm-OH with acryloyl chloride. The macromonomer was characterized by FT-IR, 1H NMR, UV-spectrophotometer, which has a lower critical solution temperature (LCST) of 36.4℃ in aqueous media. Then PDEAm grafted poly(acrylonitrile/styrene) (PDEAm-g-PAN/PSt) polymeric microspheres can be prepared by dispersion copolymerization of PDEAm macromonomer with AN /St in ethanol/water mixed solvents. The morphology and the average size of the polymeric microspheres can be controlled by changing the polymerization conditions. Scanning electron microscopy (SEM) images and particle size analysis under different temperature show that the miceospheres have monodispersibility and thermosensitivity.
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