15 November 2012, Volume 43 Issue 21

    

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综述
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  Research Progress on Die-upset Texture of nanocomposite permanent magnetic Alloys

  ;PAN Jing ;;Xin-cai LIU

  . 2012, 43(21): 1-0.

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  The easy magnetization axis crystal texture (magnetic texture) of R(Nd, Pr)2Fe14B phase is difficult to be obtained during the hot deformation of nanocomposite permanent magnets, which becomes a critical problem that needs to be solved for high performance of the magnets. Recently, by adding element Cu or Zn, as well as applying big single axis strain, the magnetic texture in die-upset R-lean Nd-Fe-B alloys has been achieved, and the texture formation mechanism has been researched. In addition, a new kind technology of Electric Backscattered Diffraction (EBSD) has begun to be applied in charactering the magnetic texture of Nd-Fe-B permanent magnets, and certain experiences have been accumulated, which will be helpful to the researches on the texture formation mechanism of die-upset R-Lean Nd-Fe-B alloys. In this paper, these works are reviewed.
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  Research progress in the preparation of patterened sapphire substrates for high-efficiency and high-power GaN-based LEDS

  . 2012, 43(21): 2-0.

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  Patterned substrate sapphire has attracted much interest in recent years due to its outstanding properties in improve GaN epitaxial crystal quality and light output powers of the LEDs. In this paper, the fabrication methods of patterned substrate sapphire are reviewed, including dry etch, wet etch and epitaxial growth method. The relationship between the mechanism of improve epitaxial crystal quality and morphology of the patterned substrate sapphire (grooves, micron hole, micron columnar, micron hemispherical, nano-hole and nano-columnar) is also discussed.
研究与开发
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  Preparation of Nanoporous SiC Coating on SiC Foam

  zhen-ming YANG

  . 2012, 43(21): 3-0.

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  Nanoporous silicon carbide (SiC) coating was successfully fabricated on foam-shaped SiC ceramics by using silicon-modified phenolic resin as the coating material. The molecular level mixed silicon and carbon elements in the coating material led to in situ formation of nanoscale SiC particles and pores during the subsequent carbothermal reduction reaction. Adding an appropriate amount of activated carbon into the modified resin was beneficial for fabrication of high quality nanoporous SiC coating on foam SiC suitable for catalyst support use. By contrast, without adding activated carbon, deflects such as weak adhesion, particle aggregation and cracks were observed in the coating. Meanwhile, the specific surface area of the fabricated composite was low.
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  Preparation of mesoporous carbon fibers via blend and catalytic

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  . 2012, 43(21): 4-0.

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  In order to the effect of metal ion on preparation of mesoporous carbon fiber by blending and carbonization, mesoporous carbon fibers were produced by electrospinning blend of polyacrylonitrile (PAN) and Polyvinyl Butyral (PVB) with and without Sn2+ in this paper. The blending fibers and porous carbon fibers were analyzed by using scanning electron microscopy (SEM), differential scanning calorimeter (DSC), Fourier infrared spectroscopy (FTIR), surface porosity analyzer. The results showed that PAN and PVB in blending fibers was phase separation. And the phase behavior of PAN and PVB took place to change obviously after Sn2+ was added. Sn2+ not only improved compatibility between PAN and PVB in DMF, making fibers thick and even, but also acted as catalyzer, reducing obstacle of decomposition and carbonization between two phases. The mesoporous carbon fibers derived from blend fiber with Sn2+showed better morphology and structure. At the 6/4 mass ratio of PAN/PVB, surface area, pore volume, mean pore size were 140.7 m2?g-1, 0.26 ml?g-1 and 7.3nm, respectively. The mass ratio between two phases also has important influence on surface structure.
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  Preparation and characterization of konjac glucomannan/attapulgite nanocomposites

  . 2012, 43(21): 5-0.

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  A natural nano-clay, attapulgite (AT), was introduced for the modification of Konjac glucomannan (KGM) by solution blending, and KGM/AT nanocomposites were prepared by casting the blend aqueous solutions. The structure and morphology of KGM/AT blend films were characterized by using X-ray diffraction(XRD), FT-infrared(FTIR), scanning electron microscopy(SEM). Besides, the thermal stability, mechanical properties as well as water resistance of the composites were investigated by thermogravimetric analysis(TG), measurements of mechanical properties, and swelling test, respectively. The results show that strong interactions between KGM and AT can be generated through hydrogen bond formation. Besides, the crystallinity of KGM was slightly increased with the addition of AT to a certain degree. It was also found that the appropriate amount of AT nano-rods could be dispersed uniformly with single crystal state in the matrix of KGM while excessive AT nano-rods were easily to aggregate, inducing an irregular distribution in the matrix. In addition, the thermal stability of KGM/AT composites was improved based on the increase of initial temperature of thermal decomposition and the temperature of maximum thermo-gracimetric rate. Meanwhile, a certain improvement of the mechanical properties and water resistance of the KGM films were also observed by addition of AT nano-clay.
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  Study on Chemical Polymerization Process and The Structural Properties of Conductive Polymer PEDT

  Sheng LU ;;

  . 2012, 43(21): 6-0.

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  Abstract: 3,4 - Asian Ethylene dioxythiophene (EDT) monomer polymerization process, the chemical polymerization of PEDT film preparation process, a systematic study of polymerization conditions on the PEDT film performance, and PEDT film electricalproperties and thermal stability analysis, the results indicate that the content of the initial temperature of the polymerization process, polymerization time, conductivity enhancer, the solution of the reaction system and other factors have a significant impact on the structure and performance of the conductive polymer PEDT. Used this prepared PEDT as solid electrolyte in the manufacture of chip tantalum electrolytic capacitor, capacitor performance improved significantly, and the ESR value is less than 50mΩ. Key words: Conductive polymers, chemical oxidation, PEDT, structure and properties
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  Synthesis of coploymer of resorcinol and 3,5-dihydroxybenzoic acid using HRP/H2O2 initiation and correlation of its structure and properties

  shenghua lu ;;

  . 2012, 43(21): 7-0.

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  A phenol copolymer was synthesized by free-radical copolymerization of resorcinol (RE) and 3,5-dihydroxybenzoic acid (DBA) using horseradish peroxidase (HRP)/H2O2 initiation. The effects of the monomer composition and molecular weight (Mw) of the copolymer on the tanning properties were investigated. The structure of the copolymer were characterized by Fourier Transform Infrared spectroscopy (FTIR), Nuclear　Magnetic　Resonance (NMR) and Gel Permeation Chromatography (GPC) and ultraviolet visible spectrophotometer (UV-Vis). The remarkable characteristics of HRP enzymatic catalysis free-radical copolymerization are that the molecular weight is easily to control and the benzene rings of phenol copolymer linked together produce a larger conjugated system. The applied results show that the phenol copolymer has excellent tanning properties and the shrink temperature (Ts) of tanned leather may reach to 78.6℃, and retanned leather has the merits of good selective filling, fullness and softness.
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  Synthesis Pathways of CIGS from an Amorphous Precursor Film

  . 2012, 43(21): 8-0.

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  In this paper, copper indium gallium selenium (CIGS) thin films were deposited by RF magnetron sputtering from a single quaternary target without any additional selenization, followed by one-stage annealing at different temperature (150~350 ℃) in argon vacuum (100 Pa). The as-deposited and annealed CIGS thin films were characterized by XRD, SEM, EDS, UV-vis spectrophotometer, four point probe instrument. Measurement results show that the CIGS thin film exhibit amorphous feature when depositing at room temperature. Phase evolution was occurred from amorphous CIGS precursors to CuSe phase then to CIGS phase with the increase of annealing temperature. The CuSe phase formed at the annealing temperature of 150 ℃, and it shows the lowest resistance and light transmittance in the annealed samples. CIGS phase formed as the annealing the temperature is beyond 200 ℃. The grains size, crystallization quality, resistance and light transmittance of the corresponding films are enhanced with the increase of annealing temperature.
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  Hydrothermal Synthesis of Plate-like ZnO Micro-cystal Films on Silicon Substrates

  . 2012, 43(21): 9-0.

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  The hex plate-like Zinc micro-crystal films were deposited on silicon substrates through the vacuum evaporation method and the plate-like ZnO micro-crystal films were prepared on silicon substrates by hydrothermal method. The results of XRD, SEM and EDS analyses indicate that the plate-like ZnO micro-crystals with zincblende structure have a thickness of ~ 1 μm and a length of ~ 100 nm, which grow vertically to the surface of Si substrate and assemble randomly to form a continuous film. Base on the morphologies of oxidation product of Zn micro-crystal film on Si substrates at ambient, the mechanism of Zinc hydroxide dehydration – zinc oxide aggregation is suggested to explain the formation process of the plate-like ZnO micro-crystal films on silicon substrates. The photoluminescence spectrum shows that the ZnO micro-crystal films are with a strong emission peak at near edge band-gap and weak emission peaks related to defects.
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  Nano Cu3(BTC)2 Fabricated by Coordination Modulation Method at Room Temperature

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

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  Abstract: Cu3(BTC)2 (HKUST-1, BTC=1,3,5-benzenetricarboxylate)，one of the most well-known coordination polymers, has been synthesized at room temperature using coordination modulation method. By adjusting the concentrations of the reactants, Cu3(BTC)2 crystals in the size range of 50-200 nm were successfully obtained. The products were characterized by powder XRD and TGA. The results show highly crystalline particles with good thermal stabilities. N2 sorption measurements reveal large BET surface areas and total pore volumes. The significantly smaller particle sizes and high capacity of gas sorption are considered advantageous for envisaged applications in practical industrial process.
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  Preparation and properties of La3+ -doped TiO2 nanowires

  . 2012, 43(21): 11-0.

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  Study of the extinction spectrum of ordered Au nanosphere arrays on the glass substrate

  . 2012, 43(21): 12-0.

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  Study on the corrosion resistance of Fe73.5Cu1Nb3Si13.5B9 nanocrystalline alloys in NaCl solution

  Qin Hu;Zhenghou ZhuLei YIN

  . 2012, 43(21): 13-0.

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  The corrosion resistance of Fe73.5Cu1Nb3Si13.5B9 nanocrystalline alloys in 0.1mol/L NaCl solution and its influence to soft magnetic properties are studied. The results show that an orange precipitate was produced in the NaCl solution after corrosion, X-ray diffraction show that Fe-based nanocrystalline alloys retain amorphous -nanocrystalline duplex structure after corrosion; the effective permeability of Fe-based nanocrystalline alloys reduce with increasing of corrosion time, after corrosion for 30 days , the effective permeability decreased by 35.9%、35.3% and 27.6% at 50Hz、1 KHz and 100 KHz, respectively, coercive force increase from 0.7097 A/m to 1.117 A/m, increased by 57.4%, hysteresis loss increase from 1.819 J/m3 to 2.994 J/m3, increased by 64.6%, the soft magnetic properties of Fe-based nanocrystalline alloys are decreased after corrosion.
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  Effects of Al2O3 Content on PVDF/PVC/Al2O3 Blend Hollow Fiber Membrane

  Xiao Luo;Shuang-Shuang Teng;;;ma-tai DING;

  . 2012, 43(21): 14-0.

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  The hollow fiber membrane was prepared by blending polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC) and nano-Al2O3. The effects of Al2O3 content on the performances of PVDF/PVC/Al2O3 blend hollow fiber membrane were investigated. The results demonstrated that pore structure and hydrophilicity of the blend membrane were improved significantly after adding suitable content of Al2O3. In addition, the amount of macropore decreased and that of micropore increased after adding suitable content of Al2O3. When Al2O3 content was 3% (wt%), the water flux of the blend membrane could reach 301 L?h-1?m-2 and the rejection of bovine serum albumin (BSA) was 77.2%, respectively.
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  High Temperature Oxidation Resistance of Nickel-base nano-ZrO2 Composite Coating Prepared with Electro-brush Plating

  . 2012, 43(21): 15-0.

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  Nickel based composite coating with nano-ZrO2 particles was prepared by electro-brush plating. The microstructure and high temperature oxidation resistance of Ni/ZrO2 composite coating were studied with scan electronic microscope and X-ray diffraction compared with fast nickel coating. The results show that the surface morphology of Ni/ZrO2 nano composite coating is relatively smooth and compact and the crystal size obviously reduced. High-temperature oxidation test in air at 800℃ indicates that the grain size of Ni/ZrO2 nano composite coating after oxidation is still smaller and more evenly and the weight-increased rate is obviously lower than that of fast nickel coating.
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  Influence of Bi2O3 dopant on microstructure and magnetic property of Li0.45Ni0.2Ti0.1Fe2.25O4 ferrites

  . 2012, 43(21): 16-0.

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  Abstract: Ferrites of Li0.45Ni0.2Ti0.1Fe2.25-δO4, doped with different Bi2O3 contents on the basis of iron deficiency content δ at 0.06, were fabricated by oxide ceramic processing. Result shows that Li-ferrite doped with Bi2O3 exhibits a single phase with pure spinal structure and are crystallized well. Appropriate content of Bi2O3 helped to improve microstructure which contributed to increasing saturation magnetizations and remanence ratios and decreasing coercivety. Ferrite with the doping content at 1.5wt% shows well combination property with apparent densities d at 4.72g·cm-3, saturation magnetizations 4πMs at 2275Gs, remanence ratios R at 0.853 and coercivety Hc at 2.9Oe.
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  Study on Porcine Acellular Dermal Matrix Crosslinked by Genipin

  Nian-hua DANWei-hua Dan ;;

  . 2012, 43(21): 17-0.

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  Porcine acellular dermal matrix (pADM) was crosslinked by serial dosage 0%, 2%, 4%, 6%, 8%, 16% (wt/wt) of Genipin (GP) respectively, and the properties of which were characterized with shrinkage temperature（Ts）, rate of hygroscopicity, adhered water, absorbtion water, FT-IR, and SEM before and after crosslinked. With the increase of GP concentration, Ts of GP-pADM was enhanced obviously, but tensile strength declined. Observed from the SEM images of the material surface, the holes of GP-pADM tended to shrink after crosslinked, which resulted in the fall of the rate of hygroscopicity, adhered water,absorbtion water. Conjugated bouble-bonds were discovered and formed a new absorption in δ2358.48cm-1 after crosslinking. Acute oral toxicity was not appear and cytotoxicity of extraction botainted from them respectively weren’t observed in L-929 fibroblasts cultivated experiment . It was concluded that genipin was a superior crosslink agent for pADM.
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  Research of Bonding Strength of Ni Microstructure on Different Substrate

  . 2012, 43(21): 18-0.

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  Titanium or Cr/Cu seeding layer was deposited by r.f. sputtering on glass substrate, The surfaces of Ti substrate were treated with some chemical regent before electroplating of Ni microstructure. The effect of heat treatment temperature and the surface roughness on the bonding strength of Ni microstructure was investigated on different substrate. The results show that the bonding strength of Ni microstructure are greatly influenced by the surface roughness and heat treatment temperature .After heat treatment at 200°C, the bonding strength is doubled compared with that without heat treatment. Furthermore, the microstructure of the cross section of the sample was investigated using Environment Control Scanning Probe Microscope and Scanning Electron Microscopy. The factors which affect the bonding strength of Ni microstructure were discussed.
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  tudy on degradable β-cyclodextrin microsphere containing mefenamic acid

  . 2012, 43(21): 19-0.

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  The β-cyclodextrin microspheres were synthesized in inverse emulsion ,then its adsorption to mefenamic acid were studied . The preparation process was optimized through the L9(34) orthogonal experimental design and the structure and performance were identified by scanning electron microscope, FT-IR spectroscopy, X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Drug loadings and sealed rate were 32.6 μg/mg and 58.7% by means of ultraviolet spectrophotometry. under the following conditions : m(β-CD microsphere/g) 1g, mefenamic acid concentration0.003 g/mL-1,time 3h, temperature 70℃. Influence factors were the reaction temperature, the quantity ofβ-cyclodextrin microsphere, the concentration of mefenamic acid ,the reaction time in order.
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  Study on the effects of modified SiO2 nanoparticles on the morphologies and properties of PVdF-HFP membranes for Li-ion batteries

  Ju-Wen MENG;Ming-Zu ZHANG ;;Jin-Lin He;

  . 2012, 43(21): 20-0.

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  Microporous separators for Li-ion batteries were made by adding SiO2 modified with different silane-coupling agents (KH550, KH560 and KH570) to the solution of PVdF-HFP. The modified SiO2 nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA). The SEM, stretching, shrinking and AC impedance test results of membranes showed that the properties of PVdF-HFP composite membranes were improved significantly by the addition of modified SiO2 nanoparticles. The electrochemical tests showed that the discharge capacity and cycle stability of the PVdF-HFP composite membranes containing modified SiO2 nanoparticles were better than that containing the unmodified SiO2 nanoparticles. Especially for the PVdF-HFP composite membrane containing SiO2 nanoparticles treated with KH-570, the tensile strength was up to 8.63 MPa, the ionic conductivity was as high as 1.53×10-3 S/cm, and the discharge capacity remained above 142 mA?h?g-1 within 100 charge-discharge cycles.
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  The effect of electrochemical polishing time on the bioactivity of conventional and ultrafine-grained TiNi alloy

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

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  The effect of electrochemical polishing time (60s, 180s) on the surface morphology and bioactivity of conventional TiNi and ultrafine-grained TiNi alloy were investigated. The results shows that with the increase of electrochemical polishing time from 60 s to 180 s, the conventional TiNi alloy exhibited much higher density of nano-scale corrosion pits but only a sligher higher bioactivity (growth rate of Ca-P layer in simulated body fluid), while the ultrafine-grained TiNi alloy exhibited much lower density of nano-scale corrosion pits and a much lower bioactivity but is higher than that of conventional TiNi alloy. The present results illustruate that besides the nano-scale corrosion pit morphology, the ultrafinement processing of microstructure is an effective approach to improve bioactivity.
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  Influence of the Various Annealing Treatment Effect on Photoluminescence Spectra of P3HT∶PCBM Thin Films

  . 2012, 43(21): 22-0.

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  The phenomance of photoluminescence spectra of poly(3-hexylthiophene) (P3HT) and P3HT:[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) blend systems was reported. The effect of various annealing treatment on the photoluminescence spectra of poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) was analyzed, photoluminescence (PL) spectra of blend films showed the PL intensity the blend of P3HT∶PCBM increase with the increasing of temperature of thermal annealing, At the annealing temperature 130 ℃, the peak intensity of photoluminescence spectra of blend films tended to the maximum, which shows that annealing treatment benefits ordered arrangement of polymer chains in the blend films.
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  Influence of artificial accelerating UV aging on carbon fiber reinforced epoxy composite

  ; Xue-Ping GAOXie Ben ;

  . 2012, 43(21): 23-0.

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  Carbon fiber reinforced epoxy resin composite was made by pultrusion process, and then artificial accelerating UV aging test was taken. Bending strength test, impact strength test, dynamic mechanical thermal (DMA) analysis were applied to study the Influence of artificial accelerating UV aging on carbon fiber reinforced epoxy composite. The results show that the bending strength and the impact strength of carbon fiber reinforced epoxy composite decayed with UV aging time, especially as an exponential function because of the influence on the outermost layer of the composite；glass transition temperature (Tg) increased relatively significant at the beginning of UV aging test, and then Tg showed no obvious change; within UV region, UV aging weaken the interface between carbon fiber and epoxy matrixto a certain extent, which gave reason to the decrease of the mechanical properties.
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  Hydrothemal synthesis of ferrite/carbon composite absorbent and its electromagnetic performance

  Jing ZHANG ;;

  . 2012, 43(21): 24-0.

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  Ferrite/carbon composite powder was prepared by hydrothermal reaction of glucose solution and BaZn2Fe16O27 powder synthesized by the solid-state method. The XRD, SEM were used to analyze the structure and the morphology of the composite powder. The vector network analyzer were used to test the electromagnetic performance of the composite absorbent at different hydrothermal reaction temperatures. The results showed that glucose was carbonized after hydrothermal reaction, and grafted on the surface of flake ferrite. The ferrite/carbon micro-nano composite absorbent was obtained. At the frequency range from 2 to 18 GHz, compared with single ferrite, the magnetic loss of composite materials was slightly increased, but the dielectric loss was obviously increased. When the hydrothermal reaction temperature was 160℃, the dielectric loss reached the maximum, and there were dielectric loss peaks and magnetic loss peaks in many places, it was beneficial to the absorption of electromagnetic wave, moreover, the absorbing band of microwave was broadened, the amount of absorbent was reduced, and the absorption effect was further increased.
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  Effects of Substrate Temperature Composite Control Methods on DC Arc Discharge Plasma CVD nanocrystallite Diamond Films

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  . 2012, 43(21): 26-0.

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  The nanocrystallite diamond films have been deposited on cemented carbide tool surface by a novel home-made DC arc discharge plasma CVD device with the substrate temperature opened and closed loop composite control system under different cooling water flow. The morphology, texture, phase and quality of diamond films was characterized by scanning electron microscopy, X Ray diffraction and laser Raman spectroscopy. The results indicated that as the cooling water flow change from 10→5→15→20 ml/min, the surface roughness, graphite phase and (110) faceted microcrystallite grains size of the nanocrystallite diamond films increases gradually with altering cooling water flow, while leading to cobalt phase diffusion from inside to surface of the cemented carbide substrate . The substrate temperature real-time altering under opened and closed loop composite control with different cooling water flow is the main factor affecting the nanocrystallite diamond film growth and quality.
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  Research on the Crystal Defects and Electrochemical Performances of Highly-Dispersed ZrO2

  Hui-Min CHEN

  . 2012, 43(21): 27-0.

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  Highly-dispersed ZrO2 nanoparticles (NPs) were successfully synthesized via sol-gel and supercritical fluid drying (SCFD) method with zirconium oxychloride as the source. The as-synthesized ZrO2 was characterized by X-ray Diffraction (XRD), High Resolution Transmission Electron Microscope (HRTEM), Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetary (CV). The results indicate that the nearly spherical ZrO2 three-dimensional network NPs possess diameters of ~10nm, and the pure ZrO2 after SCFD treatment maintains uniform crystal structure while the 3Y-ZrO2 have many crystal defects. The electrochemical performance of ZrO2 NPs showed that the pure ZrO2 NPs after SCFD treatment have very small electrochemical impedance and well-performance of cyclical stability, which provide a new orient of lithium batteries materials.
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  Synthesis and properties of anti-yellowing polymer compound with fluorescence

  . 2012, 43(21): 28-0.

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  Replacing one of the amino compounds with 4-amion-2,2′,6,6′-tetramentylniperidine free radicals capturer（4-TEMP）, the triazine-stilbene anti-yellowing monomer with fluorescence were synthesized through two-step condensation reaction with cyanuric chloride as the crosslinking monomer. The new anti-yellowing polymer compound with fluorescence were prepared by condensation reaction of the above anti-yellowing monomer with the series of polyethylene glycol (PEG). Its structure was demonstrated by FT-IR and 1H NMR, the physical properties were examined by UV-vis and photoluminescence(PL) spectra, besides the effect of anti-yellowing were evaluated – as the surface sizing agent on handsheet of chemi-mechanical pulps by using the ultraviolet aging apparatus. The results showed that in the performance of application, comparing with anti-yellowing monomer with fluorescence and the traditional fluorescent brighteners, such as VBL, the brightening effect and light stability of the new polymer compound are nice, its structure stability and anti-yellowing effect are improved obviously. At the same time, the quantum yield of fluorescence and ultraviolet ray absorption performance of the new macromolecular compound are increased obviously.
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  The Magnetic Properties of Sr1-xLaxFe12-xCoxO19 Hexaferrite Prepared from Masson Pine Sapwood

  . 2012, 43(21): 29-0.

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  Abstract: The Sr1-xLaxFe12-xCoxO19（x=0～0.2）ferrites were prepared by so1-gel method from Masson Pine sapwoods.The microstructure,morphology and magnetic properties of the sample were characterized by XRD,SEM and VSM.Results show that the morphology of the La,Co-doped strontium ferrite remained the Multilayer wall structure of Masson Pine sapwoods.The thichness of the thin layer wall was within the range of 1～2μｍ and the grain size of polycrystalline ferrite was approximated to be in the range of 1～1.5μｍ.Each grain was only horizontally connected together to form polycrystalline tracheid walls.The saturation magnetization of the sample increased with the increase of x value. The coercive force increased first,and then decreased with the increase of x value. But we observed significant low value of the coercive force in the parallel direction(A direction) compared with other direction(B and C direction).
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  In-situ construction on the surface of the biological materials and characterization of Collagen nanometer thin films

  Wei ZHOU;Rong Hua ZHANGPeng ZHAO;Chao LIN;;

  . 2012, 43(21): 30-0.

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  Nanometer thin filims with type I collagen as main component were constructed by electrostatic layer-by-layer self-assembly technique. The thickness and the plies of the films show linearly relationship. By the way of spraying, the thickness-controllable collagen films could be in-situ formed on the surface of biodegradable polyester materials without any chemical treatment to improve the hydrophilicity of the polyester materials greatly. In the mouse fibroblast (L929) culture experiments, polylatic acid (PLA) covered multilayer films demonstrated good biocompatibility.
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  Theoretical study on the performance of porous silicon explosion

  Xiao-Hua HU ;;

  . 2012, 43(21): 31-0.

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  With the methods of model chemistry and DFT calculation,this paper calculates the model of different number of silicon atoms, which synchronously adsorbe some marerials such as H,O,,NO3-.And it calculates the vibration frequency of SiHX .This paper analyses the factors of overlap population and FT-IR . The results show that it can cause an explosion for the porous silicon surface adsorption of H, Oand nitrate can weaken the Si-Si bond, resulting in the emergence of silicon hydroxide, thus oxidation or rupture to generate Si-H or Si-O molecular fragments.
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  Finite element analysis of the foreshortening property of customized coronary stents

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  . 2012, 43(21): 32-0.

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  Foreshortening is an important property of customized coronary stents, deciding the choice of stent and precise positioning of stent length. The primary aim of this investigation was to investigate the effects of varying customized stent “design parameter” and expansion diameter on the foreshortening of stent by using the finite element method (FEM). The results show that L-stent forshortening was the best and the M-stent the worst. The amplitude and expansion diameter are the dominant parameter in this study. Increasing amplitude decreases forshortening rate. However, Increasing expansion of stent increases forshortening rate of stent. Besides, Strut thickness, strut width, amplitude or radius of curvature and the length of link influence the forshortening hardly. In conclusion, FEM can quantify some mechanical behaviors of stent and help surgeons to select stent and designers to optimize stent.
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  Effect of components on viscosities and coefficients of thermal expansion of borosilicate glasses

  wang yanhang ;;

  . 2012, 43(21): 33-0.

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  The effect of components on viscosities and coefficients of thermal expansion of borosilicate glasses were studied. With the increasing of B2O3/SiO2 ratio, the viscosities of borosilicate glasses decrease, and their coefficients of thermal expansion increase. When Al2O3 replaces SiO2, the viscosities of borosilicate glasses enhance, but their coefficients of thermal expansion have little change. The viscosities rapidly decrease and coefficients of thermal expansion increase if Li2O is adopted. ZnO can also improve the melting of borosilicate glasses, but its influence is less than Li2O’s. When CaO replaces Na2O, the viscosity change of high temperature is little, but that of low temperature is much. The coefficients of thermal expansion decrease when ZnO and CaO are adopted. If a few TiO2, ZrO2 and La2O3 are introduced, the viscosities of borosilicate glasses decrease and their coefficients of thermal expansion have little increase. The coefficient of thermal expansion of E glass is matched excellently with that of Kovar alloy, indicating that E glass has a great potential application.
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  Preparation and properties of poly(butylene succinate)/ hydrotalcite nanocomposites

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  . 2012, 43(21): 34-0.

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  Biodegradable poly(butylene succinate) (PBS) and hydrotalcite (HT) nanocomposites were prepared via melt blending in a twin-screw extruder. The microstructure, crystallization, spherulitic morphology and mechanical properties of PBS and its nanocomposite were studied by SEM, TEM, DSC, XRD, POM and DMA in detail. HT nanoparticles were found to be well distributed at the nanometer level. The addition of HT is found to enhance the crystallization of PBS, due to the heterogeneous nucleation effect. POM observation shows that the nucleation density increases and the spherulite size of PBS decrease distinctly with the presence of HT nanoparticles. The tensile strength of the PBS/HT nanocomposites increased when the content of HT nanoparticles is 1%, and the elongation at break of the nanocomposites decreased whereas the Young’s modulus increased with increasing HT loading. DMA measurement indicated that a significant enhancement of the modulus of the nanocomposites is achieved.
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  Influences of La/Cu Molar Ratio and Dispersant on the Preparation and Optical Property of La2CuO4 Crystallites Synthesized by Sol-Gel Process

  Yi-Feng LI ;;

  . 2012, 43(21): 35-0.

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  La2CuO4 crystallites were prepared via a sol-gel process using lanthanum nitrate and cupric nitrate as raw materials with different La/Cu molar ratios. The phase composition, microstructure and optical property of the as-prepared La2CuO4 powders were characterized by X-ray diffraction, scanning electron microscope and UV-Vis-NIR spectrophotometer. The results show that pure La2CuO4 crystallites can be obtained when La/Cu molar ratio corresponds with the stoichiometric ratio (2:1). CuO or La2O3 impurity phase can be detected when the La/Cu molar ratio is lower or higher than the stoichiometric ratio. According to UV-Vis-NIR spectral analysis, the optical band gap is 1.37eV when La/Cu molar ratio is 2:1, while it decreases along with the appearance of impurity phase. With ascorbic acid or glucose as dispersant, the dispersity of the products is improved. Using polyethylene glycol as dispersant, the reunion phenomenon appears. And the corresponding optical band gap is 1.39eV, 1.41eV and 1.33eV, respectively.