30 April 2013, Volume 44 Issue 08
    

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    综述·进展
  • LI Jun;ZHU Jun-jun;CHENG Xiao-nong
    . 2013, 44(08): 1065-1068.
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    Negative thermal expansion (NTE) material has an abroad potential application in the electronic, aero and optical areas. It becomes a new research topic of materials science in recent years. The research progress of NTE rare earth Tung state materials is introduced in this paper in detail,including Sc2W3O12, Lu2W3O12 and Y2W3O12. The NTE mechanism for this kind of materials is explained with the “quasi-rigid unit mode” theory. And this paper prospects the NTE research orientations.
  • 研究·开发
  • GAO Zheng-yuan;PAN Fu-sheng;TANG Ai-tao;CHENG Yi
    . 2013, 44(08): 1069-1072.
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    A novel protective coating, consisting of single layer (nanocrystalline Al2O3 thin film), was deposited on the surface of AZ31 magnesium alloy. Electrochemical system and tribological tester were performed to investigate the wear and corrosion resistance of the coated AZ31 magnesium alloy, respectively. The coating reduced its friction coefficient from 0.21 to 0.15, which consequently induced a great improvement of the magnesium alloy's wear resistance. Furthermore, the corrosion resistance of the AZ31 magnesium alloy with the coating was also enhanced with the corrosion current density decreasing from 2.009 × 10? 4 A/cm2 to 6.792 × 10? 6 A/cm2 in a 3.5 wt.% NaCl solution.
  • WU Hui;MA Yong-jun;ZHU Dong-sheng;PEI Chong-hua
    . 2013, 44(08): 1073-1076.
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    Abstract: Carbonated bacterial cellulose/graphene (CBC/CCG) compositions were prepared by the ultrasonication and in situ reduced using hadrozine hydrate, with a mass ratio of graphene oxide(GO)/CBC,(7:3).Scanning electron microscopy(SEM)、atomic force microscopy(DFM)、X-ray diffraction(XRD) and laser Raman spectoscopy(Raman) were characterize the samples.The capacitive behaviors of the CCG/CBC composite and CCG as electrodes for supercapacitors were compared in terms of cyclic voltammograms, charge-discharge curves and electrochemical impedance spectroscopy(EIS)in 6mol/L aqueous KOH.The results showed that the speci?c capacitance of CBC/CCG composites could be up to 168.99F/g under the current density of 10mA/cm2,which was superior to CCG of 87.79 F/g, indicating that CCG/CBC composites have good prospects for electrochemical applications.
  • XIE Yong;JIE Wan-qi;WANG Tao;CUI Yan;GAO Jun-ning;YU Hui;WANG Ya-bin
    . 2013, 44(08): 1077-1080.
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    Catalyst-free ZnO thin nanowires were epitaxially grown on a-plane sapphire using a seed layer. X-ray diffraction and temperature dependent temperature photoluminescence (PL) measurements confirm the desired epitaxial relationship and very high crystalline and optical quality. The luminescent peak at 3.37737 eV was assigned to be free exciton luminescence by temperature dependent PL, Vashni model fitted well of the peak shift of the free exciton while from 60 K to 150 K Vina model fitted better. Through the donor-accepter pair peak at 3.29 eV,the net donor carrier concentration was calculated to be 1.8×1018 cm-3, which fairly comparable to other electrical measurement.
  • 工艺 技术
  • JIA Ying;LI Jian;YAN Jun
    . 2013, 44(08): 1081-1085.
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    The SnS thin films were thermal evaporated on glass substrate, of which the mixed ratio for Sn:S is 1:0.2(wt%). After heat-treatment at 350℃ for 40 min in nitrogen atmosphere, simple orthorhombic SnS polycrystalline films were obtained, with resistivity of 103 .Zn (2wt% and 4wt%, respectively) doping was applied to improve the conductivity of SnS thin films.The experimental results showed that the structure of Zn doped SnS thin films was turned to a mixed phase with simple orthorhombic and face-center orthorhombic, and the most effective heat-treatment condition was 300℃ for 40min.The resistivity of the Zn (2wt% and 4wt%) doped SnS thin films,with n-type behavior, ranged from 1.8528×10-3 to 4.944×10-4 .Chemical states of Sn, S and Zn were +2, -2 and +2. Interstitials doping and substitutions doping both existed for Zn atoms in SnS thin films. Due to the crystal structure, the major contribution for the improvement of conductivity was the interstitials state.
  • 研究·开发
  • JIN Shao-hu;AN Guo-fei;CHEN Guo-wei;ZHAO Xiao-peng
    . 2013, 44(08): 1086-1088.
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    A sol-gel synthesis method was introduced to incorporate trivalent samarium ions into perovskite CaTiO3 nanoparticles luminescent materials. The resulting materials were characterized by X-ray diffraction (XRD). Studied the properties of luminescence of Sm3+ in the sample by measured electroluminescence and photoluminescence, Sm3+ can emit salmon pink light brightly. However, the patterns of EL and PL are not the same. After analyzed the test results, we think there are two crystal structures: Site I and Site II, and analyzed the influences of different structures on EL and PL, the EL mainly dependent on the Sm3+ in Site I, the PL mainly dependent on the Sm3+ in Site II, and validated the influences of matrixes’ structures on luminescence of Sm3+ with experiments.
  • YAN Jun;TAO Jin-bo;HU Xian-chao;SHAO Hui-ping;CHEN Fei-bi;ZHANG Gang-sheng
    . 2013, 44(08): 1089-1093.
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    The microstructural characteristic of nacreous layer in freshwater cultured pearls was investigated by field emission-scanning electronic microscope(FE-SEM).It is shown that the thickness of aragonite platelets varied in all specimens. Furthermore, the further from the center of pearl, the greater the thickness of aragonite platelets. In addition, it was discovered that the thickness of aragonite sheets are obviously different in nacreous layer nearly out surface region of pearls with different color, at the same time, the "terraced" structure and morphology are also different on pearls surface. The more compact "terraced" structure is, the thinner the thickness of aragonite platelets near the surface of pearl is.
  • LI Yong-sheng;SHUAI Mao-bing;ZHOU Yuan-lin;CHEN Hui;TANG Xian-chen;DONG Fa-qin;XIAO Bin
    . 2013, 44(08): 1094-1097.
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    Parylene C (PC) film prepared by means of thermal chemical vapor deposition polymerization had excellent barrier properties and was widely used in many fields. But its application was limited in some extent due to its poor impact resistance. In order to overcome this limitation, a UV-cured flexible film was developed for protection of the PC film. The results showed that the UV-cured film had high adhesion to PC (zero level), good flexibility and acid resistance. Both the elongation at break and impact strength of PC film with UV-cured film had all been greatly improved. And the combined film had an improved hydrogen and air barrier property while the moisture permeability had no change.
  • WU Chang-he;FENG Xiao-wei;YE Pei;FU Zhi;LIU Zhan-fang
    . 2013, 44(08): 1098-1101.
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    Abstract: To explore the effect of strain rate on the compression mechanical property of vulcanized rubber, dynamic and quasi-static compression experiments were performed by using a split Hopkinson pressure bar system(SHPB)and Material Test System machine MTS810, respectively. And the stress-strain curves were experimentally obtained. The results show strain rate effect of vulcanized rubber was not obvious at lower strain rate, however, the dynamic stress-strain relation was significantly affected by the strain rates. Elastic modulus,yield stress and flow stress was increased as the strain rates were raised, the constitutive models of vulcanized rubber based on strain-energy function theory were used to describe the mechanical behavior of vulcanized rubber under uniaxial compression loading. The stress-strain history of vulcanized rubber would be numerically simulated, and experimental results are very consistent with the simulation results.
  • LI Yan-jun;LIAO Li;XIE Ke-nan;MENG Zhi-han
    . 2013, 44(08): 1102-1105.
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    In this paper, liquid phase reductive method was used to prepare superfine WC-Co hard alloy powder with WC, CoCl2?6H2O and C6H5O7Na3?2H2O as raw materials and N2H4?H2O as reductant. Densify the powder by sinter-HIP, and WC-Co hard alloy powder was prepared with fine mechanical properties. The temperature of the system and the reaction time was explored to study coating rate of hard alloy. SEM、TEM、XRD were applied to characterize the hard alloy. Optimization conditions were ensured to prepare WC-Co hard alloy powder. Different sizes and different ways of sintering were compared to affect the mechanical properties of the hard alloy. Result shows that: the WC-Co hard alloy prepared with this method is of high purity, uniform particles and without reunion. Hard alloy after Sinter-HIP is of fine mechanical properties.
  • ZHAO Li-feng;WANG Shu-lin;XIA Li-zhen;QIU Ying-xin;JIAN Dun-liang;CUI Mao;TIAN Hui-quan
    . 2013, 44(08): 1106-1109.
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    Roller vibration milling was used to manufacture zinc nanoparticles of 20-30 nm at room temperature. The product was preheated at 260℃ and hydrolyzed with normal steam to obtain hybrid of ZnO and Zn nano-structures. The hybrid structures were put as catalyst into the methyl orange solution in darkroom at ambient temperature, a decomposition degree 80% was obtained after 60 minutes. The hydrolysate’s catalytic effect to methyl orange is excellent and the process is according with the pseudo-first-order kinetics equation. The reason of the degradation phenomenon maybe the lattice defects formed by the mechanical force to zinc powder, in the hydrolysis reaction process, these internal defects may not disappear and exist in the form of electron-hole pair. At the same time, un-reacted zinc powder is attached to the zinc oxide nanorods becoming the metal-semiconductor structures. These metal-semiconductor structures decrease the composition of the electron-hole pair effectively, increasing the catalytic efficiency signally.
  • SONG Lin-wei;HUANG Wan-xia;ZHANG Yu-bo;XU Yuan-jie;ZHANG Yang;LI Na;LI Dan-xia
    . 2013, 44(08): 1110-1112.
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    The mixture of hydrogen peroxide and vanadium pentaoxide powder is used as a precursor to prepare V2O5 sol on the muscovite substrate. Then the V2O5 film is annealed to fabricate the VO2 film. SEM, XRD are employed to analyze the morphology and microstructure of the film. FTIR and UV-Vis spectrophotometer are used to test the optical properties. The result indicate that the film is perfectly (011) orientated on muscovite substrate. The grains are compact and the size distributed uniformly. The film has excellent MIT sharpness. The phase transition temperature and the hysteresis width are lower. In the infrared, the change of the transmittance and reflectance are larger. In the visible, the thin film has high transmittance both before and after phase transition.
  • CHEN Shu;HUANG Si-da;LE Yuan
    . 2013, 44(08): 1113-1117.
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    PLA drug-loaded microspheres have been prepared by means of coaxial electrospray. PLA solution and drug solution were individually delivered to the inner and outer channel of a coaxial-tube spinneret to form the core-shell structure. Moreover, chitosan was added into the inner-channel solution with the aim of both increasing the solution conductivity and improving the hydrophilicity and function of PLA. Several influential factors on morphology and size of the microspheres have been discussed. Experimental results indicated that under the condition of the outer-channel flow rate was 3ml/h, the inner-channel flow rate was1ml/h, both the concentration of the outer and the inner channels solution were 1% (w/v), spray voltage was 20kV, and receiving distance was 15cm, the sustained released TP-5 drug-loaded microspheres with encapsulation efficiency and loading efficiency of 76.64% and 7.11% could be obtained, and the average size of the microspheres were about 1μm.
  • WANG Yu-xing;SHEN Jiang-nan;WANG Ting;DU Chun-hui;WU Li-guang;GAO Cong-jie
    . 2013, 44(08): 1118-1123.
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    Multi-walled carbon nanotubes(MWCNT) were modified by HNO3/H2SO4 mixture and diaminodiphenyl methane(MWCNT-NH2),And then MWCNT-NH2/poly(MMA-AM) hybrid membranes were prepared through in-situ copolymerization of MWCNT-NH2,methyl methacrylate(MMA) and acrylamide (AM). The structure of MWCNT,and MWCNT-NH2 were characterized by Raman spectrum, FTIR, transmission electron microscopy(TEM). The structure and performance of the hybrid membranes were analyzed by SEM,Zeta potential and sorption-swelling behavior. The results shown that the modification of MWCNT promoted the dispersion of MWCNT-NH2 in MWCNT-NH2/poly(MMA-AM) hybrid membranes. The equilibrium swelling degree of benzene(A∞,b) was higher than that of cyclohexane(A∞,c) in the hybrid membranes,but the sorption-swelling selectivity of benzene to cyclohexane(αS,b/c) of MWCNT-NH2/poly(MMA-AM) was higher than that of p-MWCNT/poly(MMA-AM). A∞,b and αS,b/c increased with increase of MWCNT-NH2 content(c) in MWCNT-NH2/poly(MMA-AM) hybrid membranes,and the equilibrium swelling degree of cyclohexane(A∞,c) was less changed. MWCNT-NH2/poly(MMA-AM) hybrid membrane displays a characteristics of benzene preferentially selective sorption-swelling for separation of benzene/cyclohexane mixture.
  • WANG Guang-min;YANG Hui;WANG Jia-heng;NING Ce;XU Yi-chen;QI Yang
    . 2013, 44(08): 1124-1127.
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    The microstructure of Al-doped nano-ZnO thin films deposited on glass substrate by sol-gel method has investigated by X-ray diffraction and transmission electron microscopy. The results show that all the ZnO films prepared on glass substrate have preferred c-axis orientation. XRD reveal that the film with Al content of 2 at.% has the highest doping level in ZnO film. Excessive Al-doping can weaken preferred c-axis orientation in the films. The increase of Al content causes the decrease of grain size of ZnO. It is inferred that the surplus Al atoms may form a state of amorphous Al2O3 and pin the movement of ZnO grain boundary, which leads to the decrease of grain size.
  • ZHOU Qing;LIU Ke;LUO Zi-jiang;GUO Xiang;ZHOU Xun;DING Zhao
    . 2013, 44(08): 1128-1131.
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    Multi-period vertically stacked InGaAs quantum dots were grown by molecular beam epitaxy in Stranski-Krastanov mode with interruption of source, the multilayered 2D-arrays In0.43Ga0.57As/GaAs(001) dots-in-a-well were obtained with tunable dimension and density. The epitaxy structure of sample is composed of 500nm GaAs buffer layer, multi-period stacked InGaAs quantum dots and 60 monolayer GaAs. The growth process was monitored real time with reflection high energy electron diffraction, the surface morphology of sample was scanned with scanning tunneling microscope after anneal.
  • NIU Jin-fen;YAO Bing-hua;YU Xiao-jiao;PENG Chao;LU Lei-lei
    . 2013, 44(08): 1132-1135.
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    The zinc porphyrin (ZnTHPP) sensitized TiO2 photocatalysts were synthesized by in –situ Solvothermal method. The photocatalysts were characterized by XRD, SEM, VU-Vis, and TG-DTA. The results showed that ZnTHPP was indeed appeared during the in-situ method, and the crystal structure and morphology of TiO2 were not affected by the existance of porphyrin. The TG-DTA and degradation test results show that ZnTHPP-TiO2 composite exhibited the better thermal stability and catalytic activity than those prepared by simple physical adsorption method.
  • CHEN Xu;LI Guo-ying
    . 2013, 44(08): 1136-1140.
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  • SHANG Jian-li;WANG Si;DONG Li
    . 2013, 44(08): 1141-1144.
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    Phase chang material energy storage microcapsules have been prepared by in-situ condensation polymerization method with PAR as core material and Super oil-absorbing resin POL as inner membrane, after the formation of inner core, microcapsule composite have been fabricated by interfacial polymerization method with hygroscopic resin SOD as outer membrane. The performance of temperature and humidity control have been tested by differential scanning calorimeter(DSC) and isothermal sorption curve, morphology and structure of microcapsule composite have been analysed using scanning electron microscope(SEM)and infrared spectra analysis. It is shown that the microcapsule composites quipped with good thermal and humility controled performance can be used as temperature humidity regulator preparation temperature humidity building materials.
  • GAO Peng;HUANG Lang-huan
    . 2013, 44(08): 1145-1149.
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    In order to enlarge the utilization ratio of the visible light, the Pr3+:Y2SiO5/TiO2 composite was prepared by sol-gel method. The as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, and ultraviolet-visible absorption spectra. Meanwhile,the composite powder (prepared under different conditions) degradation of RhB was studied. All the results proved that the Pr3+:Y2SiO5/TiO2 had more excellent photocatalytic activities than pure TiO2, mixed powders (the mixture of Pr3+:Y2SiO5 powder and TiO2 powder).Of which, as an upconversion luminescence agent, the Pr3+:Y2SiO5 can transform the visible light into ultraviolet light, satisfying the requirement of TiO2 for photocatalytic degradation. In addition, the photocatalytic mechanics of the degradation reaction was investigated.
  • ZHANG Xin-yue;MA Hua-li;ZENG Fan-guang;YAO Ning;ZHANG Bing-lin
    . 2013, 44(08): 1150-1152.
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    A mixture of nano-amorphous carbon and carbon nanotubes films was synthesized on stainless steel plates by a micro wave plasma enhanced chemical vapor deposition system. It shows excellent field emission properties with diode structure. The cathode plate and anode plate were made of normal-gate triode structure field emission display (FED) panel and its field emission performance was tested. The experimental results show that the structure of nano-amorphous carbon and carbon nanotubes films with normal-gate triode structure FED has a good gate modulation, a good field emission performance and good application prospects.
  • SONG Liu-bin;LI Xin-hai;WANG Zhi-xing;GUO Hua-jun;XIAO ZHong-liang;ZHOU Ying
    . 2013, 44(08): 1153-1158.
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    Thermal behaviors of LiFePO4 lithium-ion cells during charge and discharge process were investigated by electrochemical-calorimetric measurement. The thermal model of lithium-ion cell was established with theory of thermal conduction. The steady temperature field was simulated with ANSYS software. The results show that total heat effects during charge-discharge process of the cell were exothermic. The amount of heat and heat production rate were linear with the charge-discharge rate. With the increase of current, the amount of heat and heat production rate increased. The temperature distribution of the cell was strongly affected by charge-discharge rate and operating temperature. With the operating temperature increasing uniform temperature distribution decreased under the same rate. When the operating temperature was the same, with the rate increasing uniform temperature distribution decreased.
  • LI Di;QIAN Lin-jian;CUI Yu-ting
    . 2013, 44(08): 1159-1162.
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    Single crystal samples of Ni50.3Mn24.5Ga25.2 are grown by Czochralski method in this work. The samples are annealed and quenched in a vacuum. The influence of the annealing temperature and quenching temperature on the premartensitic and martensitic phase transition temperature of Ni50.3Mn24.5Ga25.2 single crystals is investigated by the alternating-current magnetic susceptibility. It is found that the anneal treatment induces greatly falling of the premartensitic transformation temperature, slightly reduce the martensitic transformation temperature; and premartensitic transformation become obvious with the quenching temperature rising below 1023K, but the situation is opposite when temperature above the 1023K. It is also found that the samples which underwent high temperature quenching will recover the obvious premartensitic transformation symptom after the samples being annealed again. Analysis shows that the heat treatment has an influence on the symptom of premartensitic transformation through by changing the internal stress.
  • WANG Xing-juan;ZHU Li-guang;LIU Ran;LI Zhi-hao
    . 2013, 44(08): 1163-1167.
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    Using the tube furnace, high-frequency heating furnace and mold slag film simulator, the flux film were made under tradional and high-frequency electromagnetic field conditions, and in combination with XRD diffraction and microscopic observation, the effect of high-frequency electromagnetic field on flux crystallization were analysised. On the other hand, a three dimensional finite element model of joule heat and fluid flow of high frequency electromagnetic field were developed to investigate the effect mechanism of flux crystallization properties under high-frequency electromagnetic field. The results show that there is no new phases generate under high-frequency electromagnetic field, but the high-frequency electromagnetic field can raise crystallization rate and reduce grain size significantly. It may be the main reason for this result that the high-frequency electromagnetic field provides a certain amount of energy and has a stirring effect on the mold flux.
  • XING Yang-yang;LI Rui;ZONG Lan-lan;LI Qiu-ye;YANG Jian-jun
    . 2013, 44(08): 1168-1171.
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    AgBr/titanic acid nanotubes (TAN) nanocomposites were prepared by the coprecipitation-calcination method. TEM images showed that the one-dimensional morphology of titanic acid nanotubes transformed into nanoparticles as the increase of the calcination temperature. And the XRD results illustrated that the crystal structure of TAN transformed from the orthorhombic into anatase. The UV-vis DRS spectra indicated that the absorption of TAN was significantly expand after sensitization by AgBr nanoparticles. The presence of the surface Ag species in the AgBr/TAN composites was estimated to be Ag+ by XPS analysis. The photo-degradation of methyl orange (MO) was selected as the model chemicals to evaluate the photocatalytic activity of AgBr/TAN composites. AgBr/TAN-200 showed the highest photocatalytic activity, the degradation yield of MO reached more than 90% within 30 min. As the increase of the calcined temperature, the photocatalytic activity of AgBr/TAN decreased gradually.
  • 工艺 ·技术
  • HEI Hong-jun;LI Yi-feng;LIU Yan-qing;TANG Wei-zhong;MA Shi-jie
    . 2013, 44(08): 1172-1176.
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    High Current DC extended Arc Chemical Vapor Deposition (HCDCA CVD) technique was used to deposit a SiC coating which was designed as an interlayer for diamond coatings on cemented carbide micro-tools. The result shows that a continuous and compact SiC nanostructured interlayer could be prepared by HCDCA CVD technique, and such a SiC interlayer can restrain effectively the out-diffusion of Co element and ensure good adhesion of diamond coatings to the tools without using the acid etching pretreatment to remove Co from the tools. Cutting experiment results show that there is less chips adherent on the SiC interlayer/ diamond coated micro-tools than on the uncoated tools. Moreover, surface of the workpiece machined by the coated micro-tools has fewer burrs than that machined by the uncoated tools. These results indicate that the SiC interlayer/ diamond coated micro-tools may exhibit excellent machining ability.
  • GAO Long-fei;ZHAO Dong-lin;ZHAO Hai-jing;LI Xiao;LI Feng
    . 2013, 44(08): 1182-1187.
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    The optimized vacuum/pressure impregnation technique of silica/ biocarbon composite is highly effective for the preparation of biomorphic porous SiC ceramics. Pine wood with shaped sample dimensions of 60×18×5 mm3 (axial) was selected as the raw material, samples were dried at 105 ℃ for 24 h. SiO2 sol was impregnated into pine wood under different vacuum/pressure conditions. SiO2 gel was introduced in pine after drying procedures and multiple impregnation. SiO2/pine composites were pyrolyzed at 500 ℃ under N2 atmosphere for 2 h to prepare SiO2/ biocarbon composite. The morphology and structure of the samples were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The effects of impregnation pressure and cycles on the microstructures of silica/ biocarbon composite have been systematacially investigated.
  • LI Li;YIN Feng-shi;NIU Zong-wei;YUAN Guang-ming
    . 2013, 44(08): 1188-1190.
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    In electrical discharge machining, electrode is an important factor which influences machining quality and efficiency. The SiC particles were added into the solution to make copper-based composite by using electroforming technology. The influence of diameter of SiC particles, current density, electroforming temperature on the SiC content was studied. Influence of SiC particles on surface micro morphology was also studied. Electrical discharge machining experiments were carried out to study its corrosion resistance. Results show that the grain of SiC reinforced copper-based composite is small and the surface is compact. Relative electrode removal rate decreases and its corrosion resistance is improved.
  • PAN Jian-mei;YAN Xue-hua;CHENG Xiao-nong;ZHANG Cheng-hua;XU Gui-fang
    . 2013, 44(08): 1191-1194.
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    Hierarchical porous woodceramics were prepared using sugarcane bagasse as biomass material impregnated with epoxy resin (mass ratio of sugarcane bagasse to epoxy resin=2.5:1) followed by sintering at high temperatures. The phase composition, morphological evolution and thermal stability of the woodceramics were observed by XRD, SEM and TG, respectively. The hierarchical porous structure from micrometer to nanometer scale was analyzed by mercury intrusion and N2 adsorption method. Experimental results show that the woodceramics are composed of the non-graphitizing carbon sheets and a small amount of tridymite. The woodceramics retain the tubular pores of sugarcane bagasse and have the hierarchical porous structure containing both mesopores and macropores. The macropore size distrbution of the woodceramics is in the range of 0.4-6 μm, and the BET surface area is up to 39.7m2/g. With the increase of the temperature, the BET surface area, mesopore volume and average pore diameter of the woodceramics decrease.
  • LIAO Kun-tian;XU Lv-si;LI Jia-tong
    . 2013, 44(08): 1195-1199.
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    A new kind of flame-resistance heat-insulating foam was synthesized by blending the low density polyethylene (LDPE) with the regeneration polyolefin(RPE)by employing the two-steps foaming method, in which the red phosphorus, halogen-free and flame resistant PE masterbatches were used as the flame retardant agents. The optimum blending ratio and physicochemical properties, such as the mechanical performance, flame retardancy, heat insulation performance, as well as the combustion smoke composition were also investigated. The results indicated that, in addition to reducing the cost, blending RPE could improve the low gel rate of pure LDPE, which would make it much easier to go through second pressured foaming of polyolefin foam and also the improved the capacities of the foam. In addition, The optimum blending ratio of LDPE and RPE was 50%, when performance of the material got the best: the foaming ratio was 32, the oxygen index reached 30,The vertical burning velocity was 13mm/min, the water absorbed rate was 0.0016g/cm3, The thermal conductivity was 0.017W/(m*K). After combustion, the constituents of the smoke was similar with that of the pyrolysis products of polyethylene, which indicated the PE foam material had a poor contact with oxygen in the combustion process and the dioxin and others toxic gases were also not been detected.
  • LI Meng;FAN Zhan-peng;YANG Wen-feng;QIN Wen-feng
    . 2013, 44(08): 1200-1203.
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    The surface cladding treatment of nano-sized rutile TiO2 was carried out with KH-550 silane as cladding reagent. The dispersibilities of the original and treated nano TiO2 powder in the ECL-GC-7 aerial varnish were studied. Nano TiO2 modified coating was then prepared by adding the treated nano TiO2 powder into the ECL-GC aerial coating. The ultraviolet light absorption and ageing resistance properties of the modified coating layer were characterized as well. It was found that the initial precipitations of the nano-sized particles in the aerial varnish can be visual inspected after 4h, and stable dispersed state of the powder can be maintained up to 200h with adoption of the cladding treatment and adding of R912 dispersant. After being modified by nano TiO2, the ultraviolet light absorption and ageing resistance properties of the coating layer are improved. In addition, the cost-performance ratio of the modified coating are comparatively good when the level of addition of nano TiO2 gets to 2.0 wt.%.
  • YU Hong;XIE Quan;XIAO Qing-quan;CHEN Qian
    . 2013, 44(08): 1204-1207.
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  • LIU Yua-gang;SUN Xue-zhan;WANG Shi-bin
    . 2013, 44(08): 1212-1216.
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    To combine the characteristics of different carriers for better properties, carrier combination has been a hot field in recent years. In this article, a novel nanoparticles embedded microcapsules (NEMs) was constructed for the encapsulation and release of macromolecular drugγ-globulin to extend the release period of microcapsules. The prepared NEMs showed smooth surface, good sphericity and dispersity. The capsules had no adhesion and were well distributed. The drug initial concentration, chitosan molecular weight and concentration on drug loading and release in vitro were investigated. Compared with microcapsules, NEMs could extend the release period obviously, and it would supply experimental data in the future application of NEMs in macromolecular drug release.