30 May 2012, Volume 43 Issue 10

    

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研究与开发
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  Studies on the synthesis and electrochemical performance of polypyrrole/vanadium oxide nanotubes as cathode materials

  . 2012, 43(10): 1-0.

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  Vanadium oxide nanotubes were firstly prepared by hydrothermal treatment, in which V2O5 and H2O2 were used as raw materials and C16H33NH2 as structure-directing template. And then, polypyrrole/vanadium oxide nanotubes were synthesized by exchanging organic template with conducting polymer polypyrrole. TEM and FTIR were employed to investigate the morphology and structure of the samples. The results confirmed that the template was replaced by conducting polymer polypyrrole without destroying the previous nanotubular structure. Moreover, the electrochemical performance of the synthesized samples was tested by galvanostatic charge-discharge cycling and cyclic voltammetry. The results demonstrated that polypyrrole/vanadium oxide nanotubes had enhanced capacity and improved cycle stability, the improved electrochemical performance may be attributed to the incorporation of the conducting polymer polypyrrole.
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  Preparation of MnCe(y)Ox/TiO2 catalysts and their catalytic activity for catalytic combustion of toluene

  Xin LI;; ;;

  . 2012, 43(10): 2-0.

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  In this work, a series of MnCe(y)Ox/TiO2 catalysts with different Ce/(Mn+Ce) molar ratio were prepared by impregnation method. Then, the prepared samples were characterized by X-ray diffraction (XRD), oxygen temperature programmed desorption (O2-TPD) and hydrogen temperature programmed reduction (H2-TPR). Catalytic activity tests of the prepared samples were performed in a fixed-bed reactor. The results showed that the catalysts MnCe(y)Ox/TiO2 had good catalytic activity for oxidation of toluene. The MnCe(0.1)Ox/TiO2 catalyst was the most active catalyst among the catalysts tested, and the reaction temperature required for 90% conversion of toluene was 254℃. The addition of a small amount of cerium favored the formation of smaller particles and higher dispersion of manganese species on the support. As a consequence of that, the catalytic activity of the catalyst MnCe(0.1)Ox/TiO2 was greatly improved in comparison with the catalyst MnOx/TiO2.
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  Preparation of Metallic Glass based Composites and Measurement of the Fracture Toughness

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  . 2012, 43(10): 3-0.

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  The dumbbell-shaped metallic glass based composites of (Zr0.55Al0.1Ni0.05Cu0.30)100-xTix(x=0,2,4,6,8) were prepared by copper mold casting method. Microstructure and fracture toughness of samples were studied by X-ray diffraction (XRD), universal testing machine and scanning electron microscope(SEM). The results indicate that metallic glass based composites can be fabricated by adjusting Ti addition. The structure of the alloys are composed of metallic glass and crystal when the Ti content is x=0,2,4 and the structure of the alloys are crystal when the Ti content is x=6,8. The fracture toughness of composites which Ti content is x=0,2,4 are measured by three point bending method, and the KIC value are 10.529MPa?m1/2，5.142 MPa?m1/2 and 3.446 MPa?m1/2 respectively.
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  Effect of sputtering pressure on the surface morphology of the Ge/Si Nanodots

  xiao-Song YE

  . 2012, 43(10): 4-0.

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  Abstract: A series of Ge nanodots samples on Si (100) surface were epitaxial grown with different pressures by using magnetron sputtering technique．The morphology and structure of Ge nanodots were also characterized by atomic force microscopy (AFM)、Raman and X-ray fluorescence spectrum (XRF). It is indicated that the surface roughness of the films have an abrupt transition at a critical pressure. Such transition shows a close relation with the turning point of energetic particle thermalization. The growth process of nano-island is well analyzed, and the typical growth stage of nano-island and film with the increase of pressure in certain ranges is also presented.
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  Analysis on the Reduction Mechanism of 7022 AluminumAlloy in the FSJ Jointing Area

  WANG Hong feng;

  . 2012, 43(10): 5-0.

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  Experimental study was carried out on the FSJ of 10mm thick 7022 aluminium alloy. The cross-section of jointing area was analyzed by the tool microscope. The results show that the plastic metal of seam in the advancing side along the surface of the stirring pin was squeezed into the cavity clockwise and the plastic metal of seam in the retreating side along the surface of the stirring pin was squeezed into the cavity counterclockwise. In high rotation speed of the stirring head, the plastic metal soften by shaft shoulder friction stirring was generated vortex flow and squeezed into the cavity under the pressure of shaft shoulder. With the high speed of stirring pin, the plastic metal in the cavity squeezes the base metal to the surrounding, resulting in plastic deformation of base metal. At the same time, the part of plastic metal of the bottom was squeezed to the surface of base metal, which was squeezed to the surrounding and formed the “Flash” under the action of the pressure of shaft shoulder. As the vortex flow, the metal layer of the middle was concave, and the middle position of the surface of seam was sunken. “Reduction effect” phenomenon was occurred in the jointing area. The model of “filling indirect squeeze - vortex flow” can accurately express the flow pattern of the plastic metal of jointing area and reduction formed process.
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  Removal of Toluene by Mn, Fe and Cu Oxides Catalyst Combined with Nonthermal Plasma

  Jun-Liang WU;

  . 2012, 43(10): 6-0.

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  The activity of MnOx/γ-Al2O3、FeOx/γ-Al2O3和CuOx/γ-Al2O3 catalysts for toluene oxidation was investigated in a dielectric barrier discharge reactor. The catalysts were prepared by impregnation method, and then characterized with X-ray diffraction (XRD), and temperature programmed reduction by H2 (H2-TPR). Results showed that the catalytic activity of these metal oxide catalysts for toluene decomposition followed the order: MnOx/Al2O3 > CuOx/ Al2O3 > FeOx/ Al2O3, and meanwhile the activity of these catalysts for ozone decomposition to produce active oxygen also followed the order: MnOx/Al2O3 > CuOx/ Al2O3 > FeOx/ Al2O3. The Mn loading has a significant effect on the activity of the catalysts for catalytic oxidation of toluene. The activity of the catalyst with 1 wt% Mn loading was the highest. A 100% conversion of toluene at an energy density of 20 J/L was achieved by using the catalyst with Mn loading of 1 wt%. Results of XRD quantitative analysis and H2-TPR showed that 1 wt% Mn loading was close to the monolayer dispersion threshold of MnOx on γ-Al2O3, and thus there was strong interaction between MnOx and the support, suggesting a highly dispersion system. As a result, the catalyst with Mn loading of 1 wt% exhibited the optimum performance of toluene oxidation in the plasma zone.
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  Preferential corrosion of Fe element in NiFe2O4-10NiO based ceramic for aluminum electrolysis

  he han-bing

  . 2012, 43(10): 7-0.

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  The electrolysis corrosion performance of NiFe2O4-10NiO based ceramic was investigated in high temperature melt of 78.07% Na3AlF6-9.5%AlF3-5.0%CaF2-7.43%Al2O3. The results showed that Fe/Ni atomic ratio in NiFe2O4 and NiO phase after sintered is 2.211-2.89 and 0.136-0.34, respectively, but Fe/Ni atomic ratio in NiFe2O4 and NiO phase after electrolysis is 2.07—2.335 and 0.120—0.195, respectively. So the Fe/Ni atomic ratio in NiFe2O4 and NiO phase decreased in some extent and preferential corrosion of Fe element happened in the process of aluminum electrolysis. Possibly because the synergism of chemical corrosion and electrochemical corrosion result in the preferential corrosion dissolution of Fe element.
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  The Effect of Collagen Mimetic Peptides on L929 Cells Adhesion

  Huijuan Chen;Lingrong Liu;Jingjie Wang;

  . 2012, 43(10): 8-0.

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  In this study, collagen mimetic peptides (CMPs) incorporating the triple-helical sequence or/and integrin-binding sequence were designed. To evaluate biocompatibility of CMPs in vitro, fibroblast cells (L929) were cultured. The proliferation and attachment of cell were observed in certain time．It is demonstrated that all CMPs had no obvious effect on the proliferation of L929 cells. The results also showed that all CMPs promote migration and attachment of L929 to the coated surface．And the cells attachment shape and proliferation rate of L929 were good. After coating with CMP27 which containing the triple-helical sequence and integrin-binding sequence, the cell adhesion and spreading of L929 were significantly improved compared with others, and comparable to that observed on type I collagen. The triple-helical sequence and the integrin-binding sequence were shown to be important roles on promoting cell adhesion collaboratively. Therefore, CMP is effective for improving the bioactivity of cell adhesion, and could be potentially used as an adhesive for biomedical application. Moreover, this study provided new insights in designing other peptide-based bioactivity materials.
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  Growth and Characterization of Cd1-xZnxTe(x=0.2) Crystals by Temperature Gradient Solution Growth

  Dong Wang ;;;;;

  . 2012, 43(10): 9-0.

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  Cd1-xZnxTe(x=0.2) bulk crystals with the Al dopant and In dopant have been grown by the temperature gradient solution growth (TGSG) with the lower starting growth temperature of 1223K, temperature gradient of 20-30 K/cm and growth rate of 1mm/h. IR microscopy, FTIR transmission spectroscopy, SEM/EDS and I-V characteristics were adopted to analyze the Te inclusions, IR transmittance, Zn component distribution and resistivity of the crystals, respectively. The results showed that the density of Te inclusions in the first-to-freeze and stable growth of the ingots were 8.3×103/cm-2, 9.2×103/cm-2 respectively, which were about 1 magnitude order lower than that of ingots grown by the vertical Bridgman growth, while the corresponding IR transmittance of the ingots were 61%, 60%. The resistivity of the Al doped CdZnTe crystal was 1.05×106 Ωcm, while the resistivity of the In doped CdZnTe was 7.85×109 Ωcm. In addition, the radial distribution of the Zn component was uniform in the first-to-freeze and stable growth of the ingots.
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  Experimental Study on Carbothermic Reduction of Magnesia by Calcium Fluoride as a Catalyst

  . 2012, 43(10): 10-0.

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  The reducibility of four carbonaceous reducing agents selected for magnesia (MgO) were coke > charcoal > activated charcoal > graphite, primarily determined by reduction rates. With the optimal coke as a reducing agent, the orthogonal experiment of MgO reduction was carried out. The results have showed that the particle size of coke was most important, followed by soaking time, carbon content and least-important temperature. Moreover, the introduction of calcium fluoride (CaF2) into the reduction system can accelerate the reduction and therefore increase reduction rates at lower temperature. At 1500°C/1h, the reduction rate with 3%CaF2 increased from 67% to 99% and at 1400°C/1h that with 5% CaF2 up to 91%.
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  Beating Effects On The Synthesis Of Polyurethane From Plant Fibers

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  . 2012, 43(10): 11-0.

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  Abstract: In order to understand the influence of fiber beating on the synthesis of polyurethane from plant fibers, its physical properties, surface feature, valence bonds were tested. Based on the analysis of physical properties on the fiber based polyurethane composites, the dry tensile index, wet tensile index, folding endurance and tear index were all increased with the increase of beating degree, when the adding dosage of imidazole-TDI-PEG400 (called ITP400 for short) was 10% (of absolutely dry pulp) . When the beating degree was 55°SR, the dry tensile index, wet tensile index, folding endurance and tear index of the obtained composite can be increased by 1.06 times, 9.75 times, 1.12 times and 1.12 times. The SEM observation of treated composite reveals the dosage of needles and membrane ,which may form crosslinking between fibers, was increased with the increase of beating degree. The XPS characteristics show that the content of urethane bond was also increased with the increase of beating degree. The content of urethane bond was 1.63% when the beating degree of composite was 75°SR, which is 6.30 times more than composite of 10°SR.
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  Study on preparation and luminescence properties of Ce, Cr co-doping YAG glass ceramics

  ;XIANG Wei Dong ;;;

  . 2012, 43(10): 12-0.

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  At present, the color index of white LED is low due to the weakness of red emission. The red emission and color index of the Ce: YAG (Ce: Y3Al5O12) phosphor used for white LED have been enhanced by doping Cr3+. The crystalline phase structure, luminescence properties and lifetime were examined by X-ray diffraction (XRD) and photoluminescence spectroscopy, respectively. Effect of Cr3+ on properties of the Ce: YAG glass-ceramics was studied. The principle of enhancement of red emission was also investigated. The XRD results showed that only YAG crystal have been precipitated in the mother glass after heat treatment. Characteristic excitation peak located at 460nm was observed in the excitation spectra of the Ce: YAG and Ce, Cr: YAG glass ceramics, which indicated the glass ceramics, could be effectively excited by blue light chip. Abroad emission band center located at 530nm was observed from 480 to 650 nm using blue light chip excitation. There are three red emission peaks located at 688nm, 692nm and 705nm in Ce, Cr: YAG glass ceramic due to a nonradiative energy transfer from the Ce3+(2E) level to Cr3+(4T) level, which could improve the color rendering index of LEDs.
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  Comparative Study of Synthesis and Characterization of Pr:YAG Nanoparticles Using Different Precipitator by Co-Precipitation Method

  Jing LI;

  . 2012, 43(10): 13-0.

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  Pr:YAG nanopowders were synthesized by co-precipitant method using two different precipitator--ammonium hydrogen carbonate and urea. The as-prepared nanopowders were characterized by XRD, FTIR and TEM. The reaction mechanism of different precipitator and the effect on the particle size and dispersion of Pr:YAG powders were investigated. The results show that uniform particle with good dispersion were obtained by ammonium hydrogen carbonate compared to the larger and agglomerated powders from urea. Moreover, the PL spectroscopy indicated that the larger particle will increase the fluorescence intensity of Pr:YAG nanopowders.
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  Study on Zr and Y co-doped BaCeO3 film enhencement Lightning-Strike Protection equipment

  HUANG Yan-qin

  . 2012, 43(10): 14-0.

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  Measurement of Ultra Small Residual Stress in Deep Submicron Thick Films by the Annular Thin Plates

  Da-Yong QIAO

  . 2012, 43(10): 15-0.

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  In order to sensitive measure the small residual stress in deep submicron thick films, some improvement have been made on the annular structures, Three deep submicron films of various thickness were prepared to measure the residual stress with this improved annular structures, and released in HF solution to get the critical etching length under an on line monitoring system. The critical etching length was inputted into the ANSYS software to predict the residual stress by the eigenvalue buckling analysis. Small compressive stress less than 10 MPa within films were resolved successfully with this improved annular structure, but the micro rotating structures fabricated in the same die cannot generate a distinguishable deformation and failed to measure the residual stress.
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  EG-solvothermal Synthesis of Self-assembly SrTiO3 NanoSheets and Photocatalytic Property

  Yan-Fang ZHANG;Gang XU ;;;Wei ZHENG;

  . 2012, 43(10): 16-0.

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  Strontium titanate (SrTiO3) nanosheets self-assembled by nanoparticles were successfully synthesized by ethylene glycol solvothermal reaction route with titanium oxide hydroxyl as reaction materials and potassium hydroxide (KOH) as mineralizer at 200 oC. The composition and morphology of the synthesized powders were investigated using XRD, SEM and TEM. The photocatalytic activities of the samples synthesized by hydrothermal and solvothermal method were studied through recording the degradation of rhodamine B (RhB) in UV. The result shows that the SrTiO3 self-assembly nanosheets perform better photocatalytic activities.
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  Preparation of porous ceramic suspension and modification of positively charged

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  . 2012, 43(10): 17-0.

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  In this study, industrial waste fly ash was used as the main raw material to prepare a suspended ceramic granule which has a specific density close to water （0.80～1.10g/cm3）and good wear resistance. In addition, heterogeneous condensation, repeatedly suspended ceramic coating method modified positively charged surface, and adsorption properties of modified ceramic, iron load, bulk density, apparent porosity, compressive strength, modification of surface morphology ，surface electrical and phase composition of coatings were characterized by analysis. The best modification conditions were determined by methylene blue adsorption experiments as follows: 1mol/L of ferric chloride, calcination temperature 650 ℃, roasting time 3 h. Prepared under this condition, the modified ceramic removal rate of 86.3% methylene blue, is 3-4 times that of unmodified ceramic. The test showed that the modified ceramic granule was covered with a layer iron oxide with uneven thickness. The main phase of iron oxide layer was α-Fe2O3 which exhibited porous structures.
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  Effects of pH value on synthesis of polyphenylpropiolic acid

  TANG Jian Guo

  . 2012, 43(10): 18-0.

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  Abstract: Acetic acid of phenylpropiolic acid (PhPA) is an effective terminator, so PhPA can not be directly polymerized. After adding NaOH, the monomer is conversion into sodium salt. Then phenylpropiolic acid salt was polymerized into phenylpropiolic acid salt. With HCl acidification, we can get phenylpropiolic acid. The monomer was synthesized by the addition reaction of cinnamic acid with bromine and the followed elimination reaction. The structure and properties of both PhPA and PPhPA were confirmed by IR, UV, FS, GPC and TGA. The disappearance of the characteristic vibrations at 2212cm-1 (C≡C) and the appearance of the characteristic vibrations at 1602 cm-1(C=C) indicated the polymerization of monomers (Mw=10552) which has higher molecular weight and absorption spectra than without NaOH. On the fluorescence investigation of the polymer, the solutions of polymer emit blue light and show the peak emissions at 465 nm when excited at 375 nm. The polymer also has thermal stability.
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  Hydrothermal Synthesis and Characterization of Perovskite Oxide

  he lijie

  . 2012, 43(10): 19-0.

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  The perovskite-type AgNbO3 crystals was prepared by mild hydrothermal method and determined by powder X-ray diffraction. Rietveld refinements indicate that AgNbO3 crystallize in trigonal system with space group R-3C. The compounds were characterized by scanning electron microscopy (SEM), Brunauer-Emmet-Teller surface area (BET), XPS, FTIR and UV-vis diffuse reflectance spectra (UV-vis DRS). The photocatalytic activity of AgNbO3 powders were evaluated by degradation of gentian violet under visible-light irradiation. The result showed that the titled compound have high photocatalytic activity at room temperature and potential future applications in photocatalysis.
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  Preparation and Performance of Siloxane Modified WPU/ATO Hybrid Dispersions

  Wu Jin Li

  . 2012, 43(10): 20-0.

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  Abstract:: WPU/ATO hybrid dispersion was prepared through synthesized waterborne polyurethane (WPU) and nano antimony tin oxide (ATO) dispersion. The influences of the crosslinking reaction ofγ-glycidoxypropyltrimethoxy silane (KH560) on the performance of formed films were investigated in paper. FTIR proves that the condensation reaction between silanol, and the esterification between carboxyl of WPU and epoxy groups in KH560. Functional films were modified with post-crosslinking reaction, and the hardness, adhesion and water resistance were improved effectively, while sufficient transparency and excellent heat insulation performance remain as well. When the contents of KH560 and ATO are 3.0% and 7.0%, pencil hardness, adhesion force and water absorption reached 2H, 0 degree and 10.7%, respectively. On the otherhand, the average transmittance for visible light is 70.1% and the shield rate to near infrared light is 66.5%, therefore exhibiting effective heat-insulatability and transmittance.
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  Microwave Hydrothermal Synthesis of γ-AlOOH and γ-Al2O3 nanosheets

  . 2012, 43(10): 21-0.

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  γ-AlOOH nanosheets were successfully prepared via microwave hydrothermal method at 180℃ for 30 min, by using Al(NO3)3?9H2O, urea as raw materials and polyvinylpyrrolidone (PVP) as surfactant respectively. The morphology-contained γ-Al2O3 can be obtained though the thermal decomposition of γ-AlOOH precursors at 600℃ for 2h. The as-prepared products were characterized by SEM, TEM, SAED and XRD etc. Finally, γ-Al2O3 nanosheets were used to adsorb Congo red from water solution. The experimental results shown that γ-AlOOH nanosheets about 1 μm long, 30nm thick can be obtained by using the microwave hydrothmal method. The morphology-contained γ-AlOOH nanosheets were obtained after a thermal decomposition process, and nanometer-size holes appear on the surface of the nanosheets. γ-Al2O3 nanosheets are powerful in the removal of Congo red pollutant from waste water.
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  Numerical Simulation for Electromagnetic Field Effect of Laminated Composites

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  . 2012, 43(10): 22-0.

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  In order to solve the problem that the present research method of numerical simulation can not calculate the layered absorptivity, layered reflectivity and the multi angle reflectivity of laminated composites, the finite element model of laminated composites microstructure is therefore established, which is composed of carbon fibers, graphite particles and polystyrene meeting the requirement of research program, making use of Poynting vector which characterizes the direction and size of energy flow. By combining the program design and finite element method (FEM), the calculation of electromagnetic field effect are thus realized.Research results show that the designed laminated composites have a stable electromagnetic field effect in a wide frequency range: in the work frequency ranging from 2GHz to 18GHz, the absorptivity of the laminated composites could reach as high as 50%, while the normal reflectivity reaches only 10%. The oblique reflectivity decreases as the reflection angle increases. The absorptivity as well as the reflectivity of the first layer is much larger than the second layer. The results of numerical simulation meet the requirements set by the research program. The research method is applicable for any laminated composites microstructures.
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  Biomimetic modification of poly(D, L- lactic acid) via glycerophosphorylcholine and its biological assessments

  Ya FU

  . 2012, 43(10): 23-0.

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  In this study, the maleic anhydride is grafted onto the side-chain of poly(D, L-lactic acid) (PDLLA)by free radical polymerization firstly . Secondly the maleic anhydride is reacted with glycerophosphorylcholine(GPC) .Thus the phospholipid choline bionic chemical modification with PDLLA can be got. It was characterized by Fourier transform infrared spectroscopy (FTIR)and 13C-NMR. Biodegradation test showed that this functional poly(D, L-lactic acid) could significantly inhibit the acid induced degradation of the PDLLA. In vitro cell morphology observation confirmed that GPC modified PDLLA was cytocompatible. Meanwhile, protein adsorption test and platelet adhesion test revealed that the GPC modified PDLLA was also hemocompatible. These results suggested that GPC modified PDLLA could be an excellent biocompatible candidate for the development of tissue engineering scaffold and blood contacting implants.
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  Effects of phosphoric acid modification of NaZSM-5 zeolite on the properties of TiO2/ZSM-5 photocatalyst

  . 2012, 43(10): 24-0.

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  TiO2/HZSM-5 was synthesized by a sol-gel method using the supporter of HZSM-5 modified by different concentration of phosphoric acid. The photocatalysts were characterized by XRD, SEM, BET, FT-IR and XPS measurements. The results showed that phosphoric acid modification did not change crystalline structure of ZSM-g zeolite and had minor effect on the surface morphology. TiO2 was coated on the surface of the zeolite as TiO2 where titanium existed in its Ti4+ oxidation state. There was no direct chemical bonding between TiO2 and the zeolite. Surface area of the supported photocatalyst increased drastically with increasing phosphoric acid concentration. Degradation rate of Reactive Brilliant Red X-3B varied with phosphoric acid concentration, leading to the optimal concentration of 0.5 mol/L. 50%TiO2/0.5HZSM-5 showed much higher photocatalytic activity than TiO2, resulting in 93.4% degradation of the dye after 2 h of irradiation, compared with 61.0% degradation on TiO2.
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  Vitro Study of the Effect of Drug Free Layers to Drug Release of Drug Eluting Stents

  . 2012, 43(10): 25-0.

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  To retard the burst-release of Rapamycin, a film of drug free polymer（polycarbonate）was loaded as the outer layer of the stent coating. The experiments demonstrated that the release of Rapamycin was affected by the outer drug free layers, the thickness and different polymers of the outer polymer were the factors that affected the drug release. The gradient drug coating was also experimented to be another factor.
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  Preparation and characterization of the magnetic hydroxyapatite composite

  ; ;;

  . 2012, 43(10): 26-0.

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  Abstract: For the purpose of exploring the potential application of magnetic hydroxyapatite (HA) composite particles in treatment the osteoporosis due to lack of stress stimulus, a novel method was employed to fabricate HA/Fe3O4 composite particles with good bioactivity and superparamagnetism. The nano-iron oxide (Fe3O4) slurry synthesized by chemical precipitation was used as substrate in Ca, P solution to deposite HA on the Fe3O4 spheres through slowly increase of pH by decomposition of urea using urease as the catalytic. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray energy dispersive spectroscopy (EDX), vibrating sample magnetometer (VSM) and the magnet were used to characterize the substrate and the resultant samples. The results show that: it's a good method to prepare the superparamagnetic hydroxyapatite composite which has better magnetic performance by using the nano-iron oxide (Fe3O4) slurry as substrate and the Ca, P solution of certain concentration ( the Ca/P ratio of 5:3; Ca/Fe ratio of 5:3) containing the sodium chloride as the media, reacting in water bathing at 37 ℃ for 48h. The saturated magnetization (Ms) of the composite sample is 7.23emu/g, the remanence (Mr) is 0.073emu/g and the coercivity (Hc) is 3.28Oe.
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  Study of the small and dense Ge nanodots deposited on vicinal Si (001) substrate by ion-beam sputtering

  ;;;Yu YANG

  . 2012, 43(10): 27-0.

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  Small self-assembled Ge nanodots were grown densely on vicinal Si (001) substrate by ion beam sputtering (IBS) technique. The action of the adsorbed atoms on vicinal substrate was monitored during the initial growth. The topography of nanodot as well as the size and density was observed to evaluate with deposition amount. It is indicated that the diffusion of the adsorbed atoms was restricted by the step of the vicinal substrate, which promoted nucleation and suppressed the nanodots coarsening. Thus small size nanodots with high density were obtained on vicinal substrate.
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  The Mechanical Property of C/C Composites Modified by SiCNF

  Xian-Feng XU

  . 2012, 43(10): 28-0.

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  Using Nickel granules as catalysts, straight SiC nano-fibers (SiCNF) were deposited in-situ on the surface of unilateralism carbon fibers by the method of Catalytic Chemical Vapor Deposition (CCVD). The compound felts reinforced by SiCNF both and carbon fibers were prepared. With this felts as precursor, C/C composites (the density is around 1.7 g/cm3 ) was get by the method of CVD Pyrogenation Carbon (PyC). The mechanical property tests show that the C/C composites modified by SiCNF have higher flexural strength, compressive strength and rigidity. The observations by Scanning Electron Microscope and Polarization Microscope indicate that the modified by SiCNF can change the structure of PyC matrix and form the Rough Layer (RL) structure.
综述
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  An Overview on the Progresses of High Performance Barium Titanate /Polymer Composites

  Liang ZHANG

  . 2012, 43(10): 29-0.

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研究与开发
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  Preparation and Properties of Functionalized Fluorine–Containing Acrylate Copolymer

  Juan LU;

  . 2012, 43(10): 30-0.

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  The fluorine–containing polyacrylate latex with poly(hexafluorobutyl acrylate–co–butyl acrylate–co–methyl methacrylate) was developed by semi–continuous emulsion polymerization using sodium dodecyl sulfate SDS and poly(ethylene glycol) as emulsifier. The mechanical properties and water–resistance of films synthesized by different molar ratio of BA and MMA were studied. The amount of HFBA was ultimately optimized. The dosage of MMA increased, the tensile strength and the water–resistance of films were improved, whereas the breaking elongations were decreased. In addition, the introduction of fluorine has contributed greatly to the water–resistance of films. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) proved that fluorine has transferred to the surfaces. Contact angle revealed that the contract angle of films increased with the incorporation of fluorine.
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  Preparation and degradation of polymers based on 6-aminocaproic acid and β-alanine

  ;Yong-Gang YAN ;Gang Zhang

  . 2012, 43(10): 31-0.

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  Abstract: Amino acid polymers (PAA) based on 6-aminocaproic acid and β-alanine were prepared by melt condensation polymerization and characterized by Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results showed that PAA was a kind of comonomers of polyamide polymers. The comonomers were amorphous polymers when the ratio of the two monomers was 1:1. The crystallization degree and melting point decrease first and then increase with β-alanine content of the comonomers increasing, while its decomposition temperature decreases gradually. The results of degradation of comonomers in water showed that its degradation rate decreases first and then increases with β-alanine content of the comonomers increasing. The comonomers were degraded fastest and completely degraded in two weeks wile the monomer ratio is 1:1. The pH value of degradation liquid was relatively stable during the whole process. The comonomers would be potentially applied as eco-friendly materials.
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  Thermal stability and optical properties of HfTaO films prepared by reactive RF magnetron sputtering?

  Chun-Yu MA ;;;Qingyu zhang

  . 2012, 43(10): 32-0.

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  Effects of Ta doping on microstructure, surface morphology, band gap and optical properties of HfO2 thin films deposited by reactive rf magnetron sputtering have been investigated by X-ray diffraction (XRD), atomic force microscopy (AFM) and spectrophotometry. The results indicate that the introduction of Ta can improve the film crystallization temperature to 800, 900, and 950oC for HfTaO thin films containing 10%Ta, 26%Ta and 50%Ta, respectively. When the ratio of Ta/Hf+Ta is about 72%, the film remains amorphous at a high temperature up to 950 ℃. Thermal stability of the amorphous HfTaO film is significantly improved by the controlled addition of Ta. AFM results show that the amorphous HfTaO film is smooth. Refractive indice of the films increases from 1.90 to 2.15 with increasing Ta percentage. Eg is determined to be in the range 4.15-5.29eV, the band gap energy of the HfTaO films as a function of increasing Ta percentage decreases.
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  Research on water-holding and cooling concrete deisgn method and its perfomance

  Li-Qun Hu

  . 2012, 43(10): 33-0.

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  Water-holding material containing cement, fly-ash and grinding granulated blast furnace slag was poured into porous cement concrete matrix to form water-holding and cooling concrete. In the paper, design methods of porous cement concrete matrix and water-holding material were provide respectively, and water-holding and cooling concrete specimens were made to test strength, cooling effect and freezing resistance performance. Test results showed that the porous cement concrete matrix and water-holding material could meet the construction and performance demand. The 28 days compressive strength and flexural strength of specimens were 27.7MPa and 38.2MPa respectively, the surface temperature of water-holding and cooling concrete was 7 ℃ less than that of ordinary concrete under 33 ℃ of air temperature, but cooling effect would be reduced along with the decrease of water content. The specimen compressive strength decline was not obviously after freeze thaw cycles.