30 March 2012, Volume 43 Issue 06
    

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    研究与开发
  • Xiao-Dan Bai;Guo-Dong Fan;Tian-Tian Li
    . 2012, 43(06): 681-683.
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    The Poly(lactic acid-co-L-tyrosine) copolymers (PLA-co-Tyr) were synthesized via directly melt polycondensation with lactic acid (D,L-LA) and L-tyrosine (Tyr) as raw material using linear heating method. The best synthesis conditions were pressure 0.095 MPa, catalyst dosage 0.4% (mass fraction), polymerization temperature of 170℃ and polymerization time 10 h. The copolymers were characterized by viscosity-average molecular weight, FT-IR, 1H-NMR , GPC,DSC and TG . The results demonstrate that the biggest weight average molecular weight of PLA-co-Tyr is 2900. Compared with PLA , it has lower Tg and the decomposition temperature is more than 180℃. The new method with easier steps is cheaper .PLA-co-Tyr could be used in drug delivery systems.
  • Hui Li;Yu-Zhuo Li;Zhi-Ping Li
    . 2012, 43(06): 684-687.
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    Berberine-Cl imprinted polymer was synthesized on silica-gel particle as a sacrificed material by using berberine-Cl as template, MAA or 4-VP, EDMA and AIBN as function monomer, cross-linker and initiator, respectively. Polymer particle size was observed by optical microscope and its rebinding behavior to template investigated by IR spectrum and static adsorption of berberine-Cl on polymers. Results indicated a higher rebinding ability of Mip prepared by using MAA as functional monomer than by using 4-VP. This selective rebinding of template on the Mip resulted from specific affinity sites complementary to template in size, shape and functional group. Also, dissociation constants and maximum adsorption amount of two types of adsorption sites on Mip were obtained by Scatchard analysis.
  • Wen-Gang Chen;Shi-Rong Ge
    . 2012, 43(06): 688-691.
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    Two kind DlC films were deposited on single crystal silicon surfaces using the PECVD-2D plasma chemical vapor deposition system at low temperature. The surface topography and composition of the two kind films were detected with Raman spectrum, X-ray diffractometer and tridimensional stereo pattern apparatus. The friction properties were investigated by an UMT-2 type friction tester. The worn surface topography was detected with scanning electronic microscope. The results show that the surface of the two kind films are very smoothing and they can be subsumption to nano-hard film. The two kind film both have well antifriction and resistance to wear performance. The antifriction performance of the DLC film is outgo Si-DLC film and the resistance to wear performance of the Si-DLC film is outgo DLC film. The reason is that the bonding force of the Si-DLC film with the silicon substrate is stronger because the exist of the Si transition layer, and the exist of the Si transition layer also induce the antifriction performance of the Si-DLC film reduce.
  • Kun Qiu;Xin-Yong Wang;Si-Qin Pang
    . 2012, 43(06): 692-695.
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    This paper tests, analysis of the use of K24 YW1 cutting tool, the cutting of the cutting temperature. The greatest impact on the cutting temperature is cutting speed, but with the cutting speed increases the amount of the increase in cutting temperature is decreased. This is because in the cutting process, the speed increase makes the vice flank wear increased, the depth of cut decreases, reducing the cutting force, cutting temperature with the relative reduction. Cutting the impact of cutting temperature, followed by feed rate, cutting depth is minimal impact. Through the experiment of cutting and cutting temperature of empirical formula, formula for the merger of these three available cutting temperature on cutting the overall empirical formula.
  • . 2012, 43(06): 696-699.
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    Abstract: Miniemulsion emulsion polymerization is used to produce encapsulation of two-phase electronic ink nanocapsules —carbon black / TiO2 nanoparticles as dispersant phase and the mixture of tetrachloroethylene (TEC) and SPAN-80 as dispersant agent . In this experiment, Styrene (SM) - methyl methacrylate (MMA) is used as reaction monomers, hexadecane (HD) as hydrophobe, azobisisobutyronitrile (AIBN) as initiator, polyvinyl alcohol (PVA) as surfactant and ethanol as solvent. In this article, we do a lot of research on nanocapsules that encapsulate different chemicals such as organic colloidal of TiO2, carbon black nanoparticles, TiO2 nanoparticles and the pure polymer nanoparticles and discuss the effects of PVA content, ethanol and different surface modification on Nano-encapsulated particles on particle size and particle size distribution of carbon black / TiO2 nanoparticles .
  • He-Li Wan;Bao-Qiang Xu;Bing Yang
    . 2012, 43(06): 700-703.
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    Abstract: Preparation of Ti powders by calciothermic reduction of Titania and calcium chloride(AR) in vacuum furnace was investigated by XRD, SEM/EDS. The result indicates that calcium chloride was added which could effectively reduced the sintering effect and help to increase the gas-solid reduction reaction interface. The mass ratio of CaCl2 and TiO2 was about 1:4, and pieces were reduced by calcium vapor at 1273K for 6h. after leaching with hydrochloric acid, the Ti powders with low impurities was prepared. The Ti powders were irregular shape(10-20μm particle size) and the surface of powder was homogeneous and loose agglomeration.
  • Chao Lian;Ying Huang;Feng Gao
    . 2012, 43(06): 704-707.
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    The electric network and humidity sensing property of the multiwall carbon nanotube/silicon rubber composites materials under investigation were manufactured by using the multi-wall carbon nanotube and silicon rubber . Surface morphology of chemically modified and non-modified multiwalled carbon nanotube was examined by scanning electronic microscope. The electric network structure of the multi-wall carbon nanotube/silicon rubber was examined by transmission electron microscope. The electric mechanism of the multiwall carbon nanotube/silicon rubber composites materials was analyzed. The humidity sensing property the multiwall carbon nanotube/silicon rubber was studied. Results show that in the range of 11%?98% relative humidity, the humidity sensor of modified multi-wall carbon nanotube has a humidity sensitivity of about 0.03469/% RH. Moreover, the modified humidity sensors showed faster the response and better repeatability.The humidity sensitivity of the multi-wall carbon nanotube/silicon rubber composites materials indicates it promise as a kind of humidity sensitive material.It obtains a wide range of applications of humidity environment detection.
  • Guang-Sheng Zeng;Rui-Zhen Lin;Cong Meng
    . 2012, 43(06): 708-711.
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    Abstract: The mixture of azodicarbonamide and zinc oxide(AC/ ZnO) was used as a blowing agent to produce the starch-composite foams strengthened by plant-fiber and the effect of the content of the blowing agent on the properties of the foams was discussed. The optimal proportion of AC/ ZnO is 2:1 that was measured by Thermogravimetric Analysis. The initial samples were under ambient conditions at 50 % relative humidity at 25℃ for seven days befor the mechanical test. The results showed that the foams has an excellent performance in mechanical properties that tensile strength is 6.38MPa and elongation at break is 91.3%. The mixture of AC/ ZnO has a remarkable influence on the foaming of the foams by the calculation of the Rebound Rate and porosity. When the AC/ ZnO content is 1.5% to starch-composite, the foams showed that the highest rebound rate is 87.6% and the highest porosity is 91.6%.
  • Yu-fENG Sun;Shao-Bo Liu;Hui-Hua Li
    . 2012, 43(06): 712-714.
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    Graphene have attracted wide attention for its unique characteristics (e.g. electronic, thermal, mechanical etc.). Graphene oxide not only possesses the intrinsic properties of graphene but also contains many oxygen-containing functional groups such as hydroxyl, epoxy, carboxyl and carbonyl groups. Those oxygen-containing functional groups may improve the adsorbability of graphene oxide to gases which is advantageous for its gas sensing properties. In this investigation, graphene oxide was synthesized by a modified Hummer’s method. The gas sensing properties of the as-prepared graphene oxide to NH3was then investigated. The results indicate that graphene oxide exhibited excellent sensitivities to NH3 with a well linearly relationship ranging from 150 ppm to 350 ppm.
  • ;
    . 2012, 43(06): 715-717.
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    Nano-fibrous carboxymethylcellulose acetate butyrate (CMCAB) mats with excellent superhydrophobicity (water contact angle 155°) were prepared by electrospinning the kind of biodegradable cellulose derivative. By analyzing the SEM image of CMCAB fibers prepared under different solvent system, it is found that the fibers have groove surface at the solvent of methylene dichloride/ethanol with the composition of 8/2 (wt/wt). AFM image reveal that the CMCAB mats have concave-convex surface and resembled the rough surface of lotus leaves. Hydrophobicity of CMCAB mats are strongly influenced by average diameter and surface roughness of CMCAB fiber via the determination of water contact angle. In order to improve its hydrophobicity,the effect of solution concentration and voltage on average diameter were researched and the electrospinning conditions were optimized based on the above results.
  • Jin-Feng Li;Rui-Qiang Liu;Qiang Li
    . 2012, 43(06): 718-721.
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    Bulk amorphous Fe80P13C7 alloy with a diameter of ~2mm can be prepared by means of a rapid J-Quenching technique at a low cooling rate(lower than 1000 K/s). A comparative study of the electrochemical corrosion behavior of Fe80P13C7 bulk amorphous alloy, melt-spun glassy ribbon and crystalline alloy had been performed by means of the testing of anodic polarization curve and the observation on the morphologies of the samples after corrosion in 1 mol/L HCl solution. The results show that bulk amorphous alloy have a higher corrosion resistance than others. This could be accounted for the fact that the low cooling rate in the preparation process makes the time of atomic structural relaxation longer and results in the increase of atomic binding energy. So the reaction rate between the atoms in alloy and ions in solution slows down and the corrosion resistance of bulk amorphous alloy is improved
  • Lei YIN;Zheng-Hou Zhu;Hai-Juan Zheng
    . 2012, 43(06): 722-724.
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    The coating with epoxy on Fe78Si9B13 amorphous alloy magnetic core and its influence to soft magnetic properies are studied. It is found that the core’s mechanical strength and the strip’s flatness are improved after coating .At the same time, a insulation layer of coating can be formed on the surface of the strip.The coatings play significant roles in decreasing the core loss of amorphous alloy magnetic cores at high frequencies.After coating,the core loss of amorphous alloy magnetic cores decreased by 14% at Bm=1T, f=1kHz. Considering the factor such as mechanical strength, magnetization, and core loss, the coating achieves best as the ratio of coating adhesive is 2%.
  • Jun-Ning Gao;Yan-Yan Yuan
    . 2012, 43(06): 725-728.
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    This paper presents the study on the influences of the final cooling processes on the morphology and micro-structure of CdZnTe film deposited via close-spaced sublimation using field emission scanning electron microscopy and x-ray diffraction techniques. The influences of both the cooling speed and whether mass transfer stopped during cooling after the growth stage were studied, using fast (furnace cooling, -8℃/min when T>400℃) and low (-2℃/min) cooling speeds, respectively. All the films obtained with different conditions possess zinc blende structure. Both lowering the cooling speed and stopping the mass transfer shall improve the film density, decrease the roughness, and reduce the texture strength of the film. The growth during cooling suppresses the two dimensional in plane spreading of the grains that blunts their edges.
  • Lin-Lin Xu;Ya-Wei Zhou;Lin-Feng Gao
    . 2012, 43(06): 729-731.
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    The core-shell PS/Ag composite nanospheres were synthesized via the method of fractional steps. Firstly, the highly monodisperse PS nanospheres were prepared by taking the emulsifier-free emulsion polymerization approach, and the carboxyl group of acrylic acid was used to modify their surfaces to be surrounded with negative charges. Secondly, [Ag(NH3)2]+ was deposited on the modified surfaces of PS nanospheres and then was reduced with the SDS as the reducing agent in the water bath environment (80℃) so as to obtain the PS/Ag core-shell composite nanospheres. The particle size distribution, morphology and structure of the prepared core-shell PS/Ag composite nanospheres were chacacterized by using the Dynamic light scattering and transmission election microscope. The influence of AA amount on the core-shell PS/Ag composite particle size and the coat of Ag shell thickness were investigated. It showed that the Ag coating became more compact and thicker with the increase of AA amount. When AA came to15%, the PS/Ag composite nanospheres with completely coated Ag were obtained.
  • Zhi-Ming Zhao;Er-Yun Ma;Xiao-Jing Zhang
    . 2012, 43(06): 732-735.
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    Abstract Si/Si1-xNx multilayers were grown by alternating deposition of Si layer and Si1-xNx layer using magnetron sputtering and reactive magnetron sputtering under different N2 flows, and the post-deposition annealing of Si/Si1-xNx multilayers was performed. Transmission electron microscopy (TEM) was used to characterize the microstructure of multilayers. The cross-sectional TEM revealed that the formation of Si3N4 nanocrystallines for 2.5sccm N2 flows and Si nanocrystallines were embedded in Si layers and Si1-xNx layers of multilayers deposited under 5.0sccm N2 flows and in Si layers of multilayers deposited at 7.5sccm N2 flows.
  • Shao-Teng Yan;Ning Bai;Jing-Ren Diao
    . 2012, 43(06): 736-739.
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    In this paper, Dy1-xSrxFeO3(x = 0.0, 0.05, 0.15, 0.25) were prepared by the conventional solid-state reaction and the microwave magnetic performance were also studied. The phase structure, morphology and particle size of Dy1-xSrxFeO3 powders were characterized by X-ray diffraction and scanning electron microscope. The electromagnetic properties were measured by network analyzer, and then the microwave absorption were calculated using YRcomputer reflection simulating software. The reflection spectra were measured by spectrophotometer. The results show that the powders are perovskite structure, and the reflection loss of single-layer coating (the thickness is 2.8mm) reaches the peak value about -20dB when x=0.3, and the bandwidth (RL ≥ -10dB) reaches 2.9GHz, and when x=0.3, the reflectivity (950nm-1200nm) was reduced to 0.05%.
  • Li Wang;Cong Liu;Chun-Yan Zhuang
    . 2012, 43(06): 740-743.
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    A key factor of preparing nano calcium sulfate is to employ a appropriate technology condition for forming reverse micelle microemulsion, which makes CaSO4 crystal grow with an ideal templating effect of reverse micelle. Homogeneous spherical nano CaSO4 with an average diameter of 70nm were prepared by using reverse micelle microemulsion of AOT, OP-10 compound surfactants/ cyclohexane / n-pentanol / water under mole ratio of water to surfactants 20, reactants concentration [Ca2+]=[SO42-]=0.125 mol/L and aging time 10 min. The influence factors such as the molar ratio of water to surfactants (ω), reactants concentration, [Ca2+]/[SO42-] value, aging time T, etc. were also analyzed.
  • Chun-Yan Ma;Chuan-Xu Luo;Li-Hua Li
    . 2012, 43(06): 744-748.
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    In order to explore the electrochemical deposition of hydroxyapatite on carbonic substrate, highly oriented pyrolytic graphite plate, which possesses a nano-scaled smooth surface, was used as the cathode substrate in the electrophoretic depositon. TEM, SEM, AFM, EDS and XRD were applied to characterize the coating composition and topography to study the influences of the deposition time, the solution pH and solution concentration on the HA coating. The results showed that it is favorable for the HA growth and obtaining porous monolayer-coating composed of flake-like microstructure when the initial pH is 5 and Ca2+ concentration is under 0.007mol/L. The XRD and EDS shows the coating is Ca-deficient HA. Moreover, With the increasement of the deposition and aging time, the HA coating is more inclined to grow perpendicularly on the substrate and has a higher calcium-phosphorus ratio. This reseach will provide necessary theoretical and experimental support for the electrochemical deposition of hydroxyapatite.
  • Zhi-Gang Zhang;Li-Zhen Hong;Jun-Gang Fan
    . 2012, 43(06): 748-751.
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    Abstract: Adsorption is one of most promising methods in deep desulfurization of gasoline. The activated carbon was modified by HNO3 oxidation, calcinations and loading with metallic ions. The desulfurization performance of the activated carbons was evaluated by adsorptive removal of thiophene from thiophene-cyclohexane binary solution with equilibrium adsorption capacity as the criterion for evaluation. The experimental results show that the surface acidity groups of activated carbon increase considerably by HNO3 treatment and improved its desulfurization performance; The desulfurization rate of modified activated carbon increased through calcinations under N2 atmosphere;Loading of Fe、Zn、Cu、Ni ion on the activated carbon improved its adsorption of thiophene , while modified by Fe ion gave the higher desulfurization rate than by other metal ions. Then, the effect of different modification method combination on the activated carbon are studied. The complex modification of active carbon, oxidized firstly by HNO3 before loading active component. its desulfurization efficiency greatly enhanced. and then impregnated by Fe ion, gave the highest desulfurization rate, which could reach 85%for the thiophene.
  • Ying-Ying Tian;En-Hui Liu;Hai-Jie Shen
    . 2012, 43(06): 752-755.
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    Novel activated carbon has been prepared from tea seed shell by activation with K2CO3. The porosity of the activitated carbon sample was studied by the nitrogen adsorption at 77 K. The testing supercapacitors were assembled with carbon electrode and electrolyte of 6 mol L-1 KOH solution. Its electrochemical properties were investigated by galvanostatic charge/discharge, cyclic voltammogram, impedance spectrum. The results showed that the specific surface area of the activated carbon is sharply increased after activation, the value is up to 1272 m2 g-1, and the electrochemical performance is obviously improved, the specific capacitance is up to 150 F g-1, which suggests that it may be promising candidates for supercapacitors.
  • Sha-Sha Wei;Guo-Qiang Tan;Hui-Jun Ren
    . 2012, 43(06): 756-759.
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    Under different alkali concentrations of the precursor solution BiVO4 powers were synthesized by microwave-hydrothermal method at 200℃, using Bi(NO3)3?5H2O and NH4VO3 powders as raw materials. The phases, structures and morphologies of BiVO4 photocatalysts were characterized respectively by XRD, FE-SEM, BET, and UV-vis methods. The photocatalytic properties of the BiVO4 powders prepared under the different alkali concentrations were also studied. The powder prepared under the precursor dissolved deionized water was BiVO4 mixed crystal with monoclinic phases and tetragonal phases with 1-3μm octahedral structure. When the precursor was dissolved into HNO3 and NaOH solutions, the as-prepared powder was 3μm pure monoclinic 3μm ball-like BiVO4. When the concentration of NaOH was increased to 4mol/L, the powder became the mixed crystal with 2μm fishbone-like BiVO4. The results of photocatalytic activity show that the order of the photocatalytic activities under UV-light was BiVO4 (deionized water) > BiVO4 (4mol/L NaOH) > BiVO4 (2mol/L NaOH). Under the visible-light irradiation, the order was BiVO4(4mol/L NaOH) > BiVO4 (deionized water) > BiVO4(2mol/L NaOH).
  • Qiang Shen;Jin-Hua Liu;Feng-Xian Qiu
    . 2012, 43(06): 760-763.
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    A new azo polyurethane with chiral atoms was synthesized with 4-nitroaniline, sodium nitrite and S(-)-α-methylbenzylamine by diazo coupling reaction. The absorption spectrum of this novel azo polyurethane with chiral atoms was characterized by UV-Vis spectroscopy. The solubility was measured with different kinds of organic solution. And the thermal property was characterized by X-5 micro melting point apparatus, by which the melting point is 165℃. This result showed that the new azo polyurethane had excellent thermal stability. Mechanical properties of the novel polyurethane with chiral atoms, such as tensile strength and hardness, were also studied. The refractive index of the polymer waveguide thin film was detected by attenuated total reflection (ATR) method at different temperature, wavelength and mode of the incident light. The results showed that the refractive index of the material decreases with the temperature rising. Compared with inorganic materials, the new material has a bigger thermo-optic coefficient. At the same time, the dispersion coefficient was calculated by the Sellmeyer Equation. The thermo-optical coefficients of the material for TM (transversal magnetic) and TE (transversal electric) modes were also studied and they are obviously different, which can be used to design and develop the novel thermo-optic switch and even all-optical switch in the future.
  • Lian-Wen Deng;Sheng-Xiang Huang;Xin Liu
    . 2012, 43(06): 764-766.
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    The recycled polystyrene was modified by magnetic fillers composing of ferrite and iron-alloy. Complex permeability, complex permittivity and microwave absorbing capability of such polystyrene/magnetic filler composite were measured by vector-network-analyzer. Results show that magnetism and polarization become stronger when the content of magnetic filler becomes more. Good microwave absorbing capability presents when the mass content reaches 15%. A few peaks of microwave absorbing in 2~18 GHz appear and the peak value around 2GHz is -12dB. The modified polystyrene composite becomes multi-functioned material presenting heat insulation, sound insulation and microwave absorbing ability.
  • Xue-Wei Dong;Xiang-Feng Li
    . 2012, 43(06): 767-770.
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    In this paper,based on the built coupled thermo-mechanical model of friction stir welding process and the heat input model,friction stir welding sequence of aluminum alloy sheets with hole was researched by finite element method, and the curve of temperature variation and transient stress variation was obtained under different weld sequence during welding process,as well as the residual deformation after welded. By comprehensive comparation of these results we could know that sequence 2 was superior to sequence 1 and sequence 3. Moreover, the FEM results were agreed much with the experimental results.
  • Liu-Jun XU;Qing-Ju LIUNing-Ning YAN;
    . 2012, 43(06): 771-774.
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    Yb-doping TiO2 photocatalysts were synthesized by sol-gel method and characterized by XRD, UV-Vis, FT-IR et al. Meanwhile, the degradation of methyl blue (MB) was investigated under fluorescent lamp to test the influence of different Yb-doping concentration and sintered temperature on the photocatalytic activity of the prepared samples. The results show that all the prepared samples consist of anatase and rutile phases. Yb-doping can extend the absorption spectrum of TiO2 to the visible light region and increase the separation of the photoelectron-hole pairs. Thus, the photocatalytic activity is improved. The best preparation condition is as follows: sintered temperature T=650℃, Yb-doping concentration: Yb﹕Ti= 0.005 (molar ratio) and pH value=2.5.
  • . 2012, 43(06): 775-778.
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    Polystyrene microspheres were successfully prepared through emulsifier-free emulsion polymerization,employing potassium persulfate as initiator,styrene as monomers.The effects of the reaction parameters such as the monomer concentration in the systems,the initiator dosage and adding mode,polymerization temperature on the particle size were investigated.The microsphere composition,surface morphology,surface potential,particle size and its distribution were characterized by FT-IR spectroscopy,transmission electron microscopy,field emission scanning electron microscopy,potential and nano particle size analyzer.The results showed that the microspheres prepared by the method were uniform and monodisperse.The monodispersed microspheres with the size from 100 nm to 200 nm were obtained.
  • Ming-Yu Li;Xiong Liu;Jun-Jun Lv
    . 2012, 43(06): 779-782.
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    A kind of novel amino fiber was prepared from styrene grafted polypropylene (PP-g-St) fiber through acetylation and amination reaction. Factors affecting the acetylation process, such as reaction time, temperature, catalyst and the amount of acetyl chloride, were investigated. The effects of mol-ratio of amine vs. acetyl, amine vs. paraformaldehyde and amine vs. hydrochloric plus reaction time were also studied to obtain the optimum amination conditions by orthogonal experiment design. The results showed that the adsorption capacity of Cu2+ could reach 2.00 mmol?g-1 by this kind of amino fiber.
  • Wei-Zhong Mai;Mei TU;Jie Kong
    . 2012, 43(06): 783-787.
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    The PEG was grafted onto the surface of polyurethane membranes using a microwave irradiation technology,which was compared with the conventional heated method. The results showed that microwave could apparently accelerate grafting polymerization of the polyurethane surface. Microwave power, reaction time as well as the mass fraction had influences on grafting effects. In this experiment, the microwave reaction could get the best efficiency when the microwave power was 100W, the mass fraction 5% and the reaction time 10 minute. Scanning electron microscopy and atomic force microscopy observations displayed that the membrane surface was smoother and in smaller destruction with microwave irradiation than with conventional heated method. The water contact angle data also indicated that the membrane surface had better hydrophilicity after grafting the PEG assisted by microwave.
  • Xin Sui;Jian Lin;Qiao Tao
    . 2012, 43(06): 788-790.
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    Traditional planar ZrO2 Nernst-type oxygen sensors still use air as the reference, so they have many shortages such as complex ceramic molding process and high cost. In order to solve such problems, we use ceria-zirconia solid solution as solid reference layer to replace the air reference, as cerium ions has a valance change between four and three. In this way, we discussed how different chemical composition and thickness of ceria-zirconia solid reference layer can make a difference to the output signal attenuation. Through adding a pump oxygen unit to inhibit the signal attenuation, the solid referenced oxygen sensor can fully meet the needs of vehicle oxygen sensor.
  • Xiao-Nan FU;Kun Li
    . 2012, 43(06): 791-793.
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    A quasi-periodic structure of Au/Si-NPA active substrate was fabricated by immersion plating gold on Si-NPA. The optimum Au/Si-NPA active substrate was characterized by FE-SEM and XRD, its SERS enhancement was tested with probe molecule R6G, and the relevant enhance mechanism was analyzed.
  • Jing-Na Bai;Xia Feng;Li Chen
    . 2012, 43(06): 794-797.
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    Alkali-treated poly(vinylidene flouride) (PVDF) grafted poly(N-isopropylacrylamide) (PNIPAAm) copolymer (PVDF-g-PNIPAAm) was synthesized via radical copolymerization and the different grafting ratio of PNIPAAm was obtained by regulating reaction time. The copolymer membranes were prepared by phase inversion method. The results indicated that the grafting ratio of PNIPAAm was enhanced with the increase of reaction time resulting in the formation of microporous structures on the membrane surface due to the pore-forming ability of the amphiphilic structure. In addition, the hydrophilicity and temperature-sensitivity were also improved with the increase of grafting ratio. At the room temperature, the copolymer membrane exhibited excellent protein-resistant property due to the hydrophilicty of PNIPAAm.
  • Fu You;Ji-Dong Li;Yi Zuo
    . 2012, 43(06): 798-802.
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    The viscosity of slurry plays an important role in fabrication of porous scaffolds by using thermally Induced phase separation method. In this paper, nano-hydroxyapatite/polyamide 66 (n-HA/PA66) porous scaffolds were prepared with n-HA/PA66 composite slurry of different viscosity to investigate the influence of slurry viscosity on structure and mechanical property of the fabricated scaffolds. The pore structure and mechanical property of the scaffolds were compared. The results showed that the pore size, pore distribution, total porosity and interconnective porosity of n-HA/PA66 scaffolds reduced with the increase of slurry viscosity, while mechanical property of the scaffolds changed in an inverse tendency. When the slurry viscosity was 330Pa?s, the n-HA/PA66 porous scaffold exhibited an appropriate average pore size of (324±67.1)μm, porosity of (75±1.6)% and interconnective porosity of (59±2.5)%, as well as compressive strength of (2.12±0.90)MPa, which will be desirable for bone tissue engineering.
  • Dan Chen
    . 2012, 43(06): 803-805.
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    The copper nanoparticles were prepared through aqueous chemical reduction method with copper chloride as the copper source, hydrazine as the reductant, cetyl trimithyl ammonium bromide as the stabilizer, ammonia water as the complexant. The results indicated that with the concentration of hydrazine decresed, the particle size of the obtained copper nanoparticles increased. The MIC values of the samples were measured to be 750~3000 mg/L by broth dilution method. The studies also showed that the smaller the size of the copper particle was, the higher the antibacterial activity displayed. Copper ions through hydrolysis or ionization may be responsible for antibacterial properties.
  • Jian-Yun Zhang;Jian-Ping Han;Xue-Hui Zhang
    . 2012, 43(06): 806-808.
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    Si/Al composite was fabricated by pressureless infiltration. Effect of infiltration temperature on Si phase shape in prepared Si/Al composite was investigated. The matrix alloy solidification microstructure of Si phase interspace was analyzed. The coefficient of thermal expansion, thermal conductivity and bending strength of Si/Al composite were tested. The results show that at same infiltration time, with infiltration temperature increasing Si phase is from particle shape to network shape in prepared Si/Al composite. The microstructure of Al-Si matrix alloy in the interspace of Si phase is no typical primary phase and eutectic microstructure. There is a phenomenon similar to the separate-eutectic microstructure. Primary Si phase and eutectic Si phase crystallize and grow at origin Si phase. XRD analyzing shows that there are Si phase and Al phase in prepared Si/Al composite. With infiltration temperature increasing, the coefficient of thermal expansion, thermal conductivity and bending strength of Si/Al composite decrease.
  • Jin-Xiang Wang;Xiao-Bo Peng;Chang-Rong Xia
    . 2012, 43(06): 809-812.
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    SnP2O7 proton conductors of χP/Sn(χ=2.0, 2.2, 2.4, 2.6, 2.8, 3.0) was synthesized and characterized as a potential electrolyte for intermediate temperature that operated range of 120°C~260°C. X-ray diffraction investigation (XRD) showed that SnP2O7 was cubic structure and Thermal gravimetric analysis (TG) showed that SnP2O7 was stable when operated at intermediate temperature. The conductivity, measured using impedance spectroscopy, improved with increasing the molar remains of HPO3 in SnP2O7, This indicates that HPO3 is responsible for the high conductivity and SnP2O7 serves as a supporting matrix. For 3.0P/Sn, the highest proton conductivity were determined to be 5.1×10-2 Scm-1 under dry atmosphere and 6.6×10-2 Scm-1 under wet atmosphere at 200℃, respectively. Because HPO3 easily causes deliquescence and exhibits strong acidity, it is critical to develop electrode materials for the intermediate temperature. The mechanism of proton conduction is examined in detail.
  • Jun-Yan Zhu;Gong-Bing Gu
    . 2012, 43(06): 813-816.
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    Zinc oxide as a typical semiconductor with adjustable conductivities can grow into different micro/nano-structures. In this paper, several types of nanostructures with multi-interfaces of zinc oxide have been prepared through hydrothermal method under atmospheric pressure, and the scanning electron microscopy (SEM) was used to observe the morphologies of the samples. It was found that different nanostructures with multi-interface could be obtained by changing the sort of zinc salts. Kinetic studies showed that the nucleation rates for different kind of zinc salts were almost equivalent, the obvious disparities of the ratios for growth stages might be ascribed to the radius and hydratability, which was speculated to the main reason why the as-prepared zinc oxides exhibit different morphologies. The electromagnetic properties of multi-interfacial structure was investigated, and the consequences indicated that interfacial behaviors exibited distinct effect on the intensity and frequency of reflectivity of electromagnetic wave.