30 December 2012, Volume 43 Issue 24
    

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    研究与开发
  • Study on Preparation of different morphological nano-ZnO array with hydrothermal method and its optical properties
    Sheng-Hui TU
    . 2012, 43(24): 2-0.
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    Nanorod, pencil-like and tower-like nano-ZnO array were prepared by hydrothermal method in this study. The structure , morphology and optical properties of nano-ZnO array samples were characterized by transmission electron microscopy(SEM), X-ray diffraction (XRD) and photoluminescence spectroscopy. The results showed that the crystal of nano-ZnO array sample was better with a strong UV emission peak at 380nm. Meanwhile, the photocatalytic investigations showed that the nano-ZnO array sample have good photocatalytic properties for degradation of the simulated pollutants (Methyl orange), and the tower-like nano-ZnO have higher photocatalytic properties than others.
  • Surface Integrity of IN718 Nickel Alloy After Electrical Discharge Machining
    Li LI ;;
    . 2012, 43(24): 3-0.
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    Nickel based super alloys are widely used in many areas because of its excellent performance. According to its turning problem, electrical discharge machining method is utilized in this paper to explore it machining surface intetrity. Experiments are carried out primarilly. The influence of pulse current and pulse on time on surface integrity is analyzed. Results show that surface roughness increases with the pulse current and pulse on time. The movement direction of has no effect on surface roughness. The SEM figures are characterized by discharge craters, droplets, micro-voids and debris. There is no micro cracks on the machined surface.The value of microhardness changes little. Low discharge energy results in small recast layer and good surface integrity.
  • Mechanical and Tribological Performances of Graphene Reinforced Polyimide Composites
    Wei-jiu HUANG ;
    . 2012, 43(24): 4-0.
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    The graphene was prepared by reduction process of graphite oxide, and the polyimide (PI) composites reinforced by graphene were prepared by solution blending method. The mechanical and tribological properties of PI composites reinforced by graphene were evaluated, and the wear mechanism was also analyzed. The results show that the tensile strength, elongation at break and hardness of the composites increased and then decreased with the increasing content of graphene, while the impact strength increased and then decreased, and rose again. The polyimide composites filled with 1 wt.% graphene exhibited the ultimate value of the tensile strength and elongation at break, the two values had been increased by 149% and 652%, compared with the pure polyimide, respectively. The addition of graphene may effectively enhance the tribological properties of composites. Along with the graphene content increased, the wear rate of the composites declined and then rose, while the friction coefficient significantly reduce at first and then gently decrease. The wear rates of the composites display the gentle decline trend with an increase of load and ascendant trend with increasing sliding speed. The main wear mechanism of the composites modified by grapheme was adhesive wear.
  • Preparation of Trifunctional Amine Terminated Polyether
    Li-Juan ZhangQiting Lu;;
    . 2012, 43(24): 5-0.
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    The effect of the activated Raney nickel catalyst composition on the catalytic amination is studied by preparation of trifunctional amine terminated polyether in a magnetically stirred stainless steel autoclave. The experiments indicate that the catalyst with 20wt% aluminium is more effective for the catalytic amination of polyether polyols, and the total amine of the product is up to 340mgKOH/g. X-Ray Diffraction (XRD) is employed to characterize the catalyst properties and the chemical composition is analyzed by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The reaction route is deduced on the basis of the products and the off-gas analysis by Gas Chromatography(GC) and Fourier Transform Infrared Spectroscopy (FTIR).
  • Design and fabrication of ceramic composites based on the cellular automata
    Bin Li
    . 2012, 43(24): 6-0.
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    The simulation of the microstructure for the ZrB2/(W, Ti)C composite materials based on the cellular automata theory and related experiments are presented. The simulation results show that: with the increases of (W, Ti)C, the morphology of the grain is changed. The grain size distribution is more suitable and homogeneous in the composite matrix with a reasonable (W, Ti) C proportion. The test results show that: the change rule of simulation basically agree with the test data. Simulation of composite materials based on the cellular automata theory, can achieve good effect for the microstructure evolution.
  • Investigation of the Preparation of MoS2 Coating on the Surface of cemented carbide by sol-gel method
    . 2012, 43(24): 7-0.
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    On the basis of MoS2 soft coating on the surface of cemented carbide was successfully obtained by citric acid sol-gel method, influence of added amount of MoS2 in the coating on sueface microscopic morphology and friction coefficient of MoS2 coating was studied by Scanning Electron Microscope and friction test. The results indicated that, MoS2 coatings with high quality and good binding with the substrate on surface of cemented carbide samples can be prepared by sol-gel method of respectively adding 13g/L, 20g/L, 27g/L MoS2 into 1.6 mol/L citrate solution and making one on the surface by burshing. The surface morphology of the MoS2 coating is of lamellar. The samples with MoS2 soft coating significantly reduces the friction coefficient from 0.6-0.8 of original sample to 0.15-0.25. But the adding amount of MoS2 in soft coating has no obvious difference in the friction coefficient. The fact that the soft coating could reduce the friction coefficient of samples could be attributed to the presence of the coating with MoS2, that has advantages of lower friction and great bearing capacity, and changed friction nature between the friction pairs materials becauce of the existence of coating.
  • Synthesis and Photophysical Behaviors of rhodamine-based sensor probe for Cu2+ detection in aqueous solution
    Hai-Qiang WU;;;;LIU Xiao-Ya
    . 2012, 43(24): 8-0.
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    A novel rhodamine-based sensor probe R6GHS was synthesized from the Schiff base reaction of R6GH with 4-(diethylamino) salicylaldehyde. The structure of R6GHS was confirmed. The UV-vis absorption and fluorescence spectrum study found R6GHS showed highly selective detection for Cu2+ over a wide range of metal ions in CH3CN-water(3:7, V/V)Tris-HCl (pH = 7.0). Furthermore, upon the addition of Cu2+, the spirolactam ring of R6GHS was opened and the solution color changed from colorless to red. Strangely, an unexpected fluorescence was observed, which is contrary to the fluorescence turn-on of the most rhodamine-based, and the response process was quick and reversible, which is promising for its practical utility in fast detection of Cu2+ in aqueous environment.
  • Magnesium and Aluminium Layered Double Hydroxide: Modification, Granulation and the Adsorptive Removal of PO43-
    . 2012, 43(24): 9-0.
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    Powder layered double hydroxide of Mg-Al LDH has been prepared by hydrothermal technology with 500 kg?batch-1, modified and granulated (MG Mg-Al CLDH) by deposition method. After modification and granulation, the fixed bed could not be accumulated and cloged by the adsorbents. MG Mg-Al CLDH has been characterized with SEM-EDX, specific surface area and pore volume, XRD, FT-IR. The surface area of MG Mg-Al CLDH was 233.34 m2?g-1, 40% higher than G Mg-Al CLDH (granulated but without modification). The mechanism of modification was hydroxyl group and ion exchange. PO43- was removed from aqueous solution by MG Mg-Al CLDH with column experiments, the breakthrough adsorption capacity was 13.49 mg?g-1, more than 6 times of G Mg-Al CLDH. The exhausted MG Mg-Al CLDH could be desorbed with 0.1 mol?L-1 NaOH and 3 mol?L-1 NaCl and regenerated with 25% MgCl2. The regeneration rate was 126.24%. After removal, the water quality could satisfy with 0.5 mg?L-1, the first degree of integrated wastewater discharge. So this work is very useful for the practical application of Mg-Al LDH and the removal of phosphorus.
  • Study of preparation and modification and properties of melamine formaldehyde resin foam
    ;;;;
    . 2012, 43(24): 10-0.
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    Melamine formaldehyde (MF) foam is one autologous fire-retardant material which can be easily self-extinguished without producing toxic drips during combustion, it can be used as thermal insulation and sound-absorption material and has a bright future. However, the shortcomings such as large fragility restrict its wider application. In this paper, we discussed the differences between morphology and compressive modulus in different ways of foaming and then the influence on foam morphology of foaming agent as well as the effect on the properties with the addition of PVA which has good flexibility, then analyzed its fire-retardant, mechanics and thermal insulation properties using LOI, compression and coefficient of thermal conductivity test respectively.
  • Ethanol Sensing Properties of Multiwalled Carbon NanoTube-doped ZnO
    ;; ;;
    . 2012, 43(24): 11-0.
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    Multiwalled carbon nanotubes (MWNTs) were prepared by chemical vapor deposition. Then the heater-type gas sensor was made by doping MWNTs in ZnO powder. The morphology of MWNTs-doped ZnO powder was characterized by scanning electron microscope (SEM). The studies reveal that the sensitivity of ZnO gas sensor is significantly improved with the addition of MWNTs. The sensitivity of the sensor is 46 and the response and recovery times are 4s and 20s respectively when the concentration of ethanol is 50ppm. It also shows the prominent selection to common interference gases.
  • The Study on the Hydrothermal Method Synthesis and Up-Conversion Luminescence Characteristic of β-NaYF4:Yb,Er(/Tm) with Different Morphology
    ;;Xi-xian Luo
    . 2012, 43(24): 12-0.
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    Hydrothermal method was used to prepare NaYF4:Yb,Er(/Tm) by adding different surfactants and the samples were characterized by means of XRD, TEM, FT-IR and up-conversion luminescence spectrum to analysis its physical phase, morphology, surface and the intensity of up-conversion luminescence. The results show that the samples are all hexagonal phase under the equivalent reactive temperature and time condition; The morphology of the samples are different from each other by adding different surfactants, we can tailor the growth of crystal by controlling the type and dose of added surfactants. The sample with citric acid as surfactant exhibits the highest intensity of up-conversion luminescence.
  • Sacrificial template-directed synthesis of YVO4:Eu hollow microspheres and their photoluminescence properties
    ;;
    . 2012, 43(24): 13-0.
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    Monodispersed YVO4:Eu hollow microspheres with average diameters of 250 nm were successfully synthesized by one-pot hydrothermal treatment of YOHCO3:Eu colloidal spheres. The structure, morphology, and photoluminescence properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), transmission electron microscopy (TEM), and photoluminescence (PL) spectrometer. The formation of the YVO4:Eu hollow microspheres was revealed to be normal solution transport process. Under ultraviolet (280 nm) excitation, the YVO4:Eu hollow microspheres showed strong red emission at 618 nm.
  • Research on drag reduction mechanism of polymer coating with binary structured surface
    ;;
    . 2012, 43(24): 14-0.
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    Experiments were performed to investigate the relationship between drag reduction property and surface topography characteristics of polymer coating with binary structured surface, and computational fluid dynamic methods were conducted to numerically simulate the process of vortex cavitation caused by binary structured surface. And based on the experiments and simulations, the effect mechanism of binary structured surface on drag reduction was analyzed. According to the results, gas phase was generated due to vortex cavitation and developed in low pressure condition provided by surface topography. With the gas phase at the solid-liquid surface, the shear force at the solid-liquid interface was partly replaced by gas-liquid interfacial shear. As the gas-liquid interfacial shear is much smaller compared with the solid-liquid interfacial shear, the skin friction drag was reduced effectively.
  • Synthesis of Cationic Water-based Polyurethane Emulsion Modified by Epoxy Resin and Its Strengthening Effect of Surface Treatment for Paper
    Jia CHEN
    . 2012, 43(24): 15-0.
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    A series of cationic water-based polyurethane emulsion modified by epoxy resin were successfully prepared by in situ polymerization using isophorone isocyanate (IPDI),hexamethylene-1,6-diisocyanate (HDI) and polycaprolactone diols (PCL1000), then epoxy resin (E-44) were introduced for crosslink modification. Fourier transform infared spectrometer (FTIR) were used to characterize the structure of the polymer. Medium resistance, mechanical properties and water contact angle of the cast films were also measured. Effects of E-44 content on the properties of polymer and sizing performance were investigated. The surface of the paper before and after treatments were observed by scanning electron microscope (SEM).The results show that the emulsion and sizing performance were excellent when n(NCO)/n(OH)=1.3，W(MDEA)=10%，W(E-44)=12%.At the same time, the papers sizing value can reach 79s, and w et strength approaches 39% , folding endurance 57 times. With the increase of E-44 content, the water absorption of the film decreased from 13.69% to 6.46%, toluene absorption from 121.5% to 74.8%,the contact angle of the film increased from 64.85o to 116.49o,as well as the mechanical strength increased.
  • Study on mechanochemical treatment PVC membranes preparation by TIPS method
    . 2012, 43(24): 16-0.
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  • Matching design and study of compatible characteristics about infrared-radar stealth
    Yu ZENG
    . 2012, 43(24): 17-0.
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    Design of infrared low-emissivity and radar high-loss compatible stealth characteristics is the urgent need and difficulty of multi-spectral stealth materials. In this paper, the electromagnetic parameters of radar high-loss materials and infrared low-emissivity materials were analyzed, using impedance matching principle, compatible design of infrared low-emissivity materials and radar high-loss materials was done. The insertion of matching layer can improve its impedance matching, infrared-radar compatible stealth characteristics was achieved, the experimental performance of multi-layer structure about infrared-radar compatible stealth materials was basically consistent with the simulation result. The study of infrared low-emissivity and radar high-loss two-layer compatible stealth materials had a certain reference for engineering applications.
  • The influence of pretreatment on kapok fiber/CdS nanocomposites morphology structure by AFM
    Ting-Ting HU;
    . 2012, 43(24): 18-0.
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    By using pretreated kapok fibers as matrices，kapok fiber/CdS nanocomposites were prepared through in situ composition with CdS. The morphology structure of nanocomposites was observed by scanning electron microscope (SEM) and atomic force microscope (AFM). The influences of the pretreatment methods on the microstructure of kapok fiber/CdS nanocomposites were characterized quantitatively by AFM. The results showed the amount of Cd attached onto the nanocomposite prepared from kapok fibers was higher than that of the untreated kapok fibers. And the CdS nanoparticles attached onto the kapok fiber/CdS nanocomposites with TEMPO oxidation dispersed most evenly, and had the most uniformly diameters. This research has a significant guiding role to the preparation and structure characterization of cellulose/inorganic nanocomposites based on plant cellulose resources.
  • Study on the Fabrication and Thermal Performance of Aluminum Substrate for High Power LED
    . 2012, 43(24): 19-0.
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    Accelerated aging tests at 1A were carried out on a new type of integrated high-power white GaN-based light-emitting diodes which we encapsulated the LED chip to the aluminum plate directly.Then the electrical,luminous and spectral characteristics were researched to analyse the failure mechanism of the device including the LED chips and phosphor.The electrical characteristics demonstrated that both the series resistance and thermionic emission current increase after aging.Luminous flux curve shows that the lower electron mobility, the higher the recombination rate, so the decay rate of the LED is slow when the drive current is low.Spectral and color temperature curves show that the phosphor degradated fast in initial stage of aging,well blue chip attenuation was dominant after a certain period of time.
  • Study of planarization efficiency of an alkaline copper slurry on 300mm pattern wafer CMP
    . 2012, 43(24): 20-0.
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    Due to the incorporation of Cu/Low-K for copper interconnects fabrication, the Cu chemical mechanical planarization (CMP) is necessary to be performed at a reduced down pressure. In this paper, we have developed an inhibitor free alkaline copper slurry, the dissolution rate results indicate that the slurry has a low etch rate on copper (20?/min), the polish results reveal that the copper removal rate can be achieved at 6333 ?/min under a low down pressure of 1.5psi. The planarization efficiency results show that the slurry has a high planarization capability, it can eliminate about 7946? step height. Atomic force microscope (AFM) test show that the copper polished by this slurry has a lower roughness (0.178nm). All the results above show that the slurry can be applied in multi-layers copper CMP.
  • Preparation and characterization of Sm3+ and Gd3+ co-doped TiO2 powders with high photocatalytic activity
    Lu Xu Dong
    . 2012, 43(24): 21-0.
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  • The influence of junction temperature on the spectral characteristics of white LED with low color temperature and high color rendering index
    Tian-Jing LIANG
    . 2012, 43(24): 22-0.
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    Mixing MEH-PPV with YAG phosphors, we utilize a new kind of light-emitting diodes which are encapsulated the LED chip to the aluminum plate directly to replace the traditional stent. The junction temperature can be directly measured by the thermocouple. Research the influence of the junction temperature on white LED spectral characteristics. Experiments show that: with the junction temperature rising, blue spectrum peak is declining and red shift is occurred; The absorption of phosphor is enhanced, while yellow and red spectral peaks increase first and then decrease; The blue shift of the red light band spectrum is occurred; And the color render index falls from 90.3 to 78.6, While the color temperature increases from 3265 K to 3672 K rapidly first, then drop to 3612 K slowly; The flux and luminous efficiency have the same variation trend which increase first and then decrease.
  • Preparation of High Purity and Ultrafine SiO2 Powder from Natural Quartz
    ;LIU Laibao Qi-Long LIAO
    . 2012, 43(24): 23-0.
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    The high purity and ultrafine SiO2 powder (the content more than 99.99%) had been prepared after those process measures included surface scrubbing, crushing, magnetic separation, calcinations, water quenching, grinding, acid leaching, washing, filtration, drying and so on, which using natural quartz of Jinzishan in Sichuan Guangyuan as the main raw materials. It was examined that removed effect of a single sour leaching treatment on main detrimental impurity (Al and Fe) by orthogonal test. And then the mix sour leaching processing which is feasible in technology and economy was obtained by experiments. The particle size (d50) of the sample was approximately 291nm by Laser particle size analysis. And the test results of ICP-OES show that the Al content is 13.65ppm and Fe 2.36ppm, which reach the technical requirements of electronics industry standard.
  • Humic acids graft copolymer of synthesis and conditions on the apparent viscosity effect
    ZHANG Guang-Hua ;
    . 2012, 43(24): 24-0.
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    By using agueous solution polymerization method, using potassium persulfate as initiator, with potassium humic acid, acrylamide as raw material was prepared by graft copolymerization。Study of the amount of initiator, monomer ratio, reaction temperature, and reaction time on the apparent viscosity effect。To determine the best process conditions of polymerization: reaction temperature 75℃, reaction time 2.5h,dosage of initiator, acrylamide and 5% humic acid mass ratio 0.8:1.When the amount of dispersing agent for coal water slurry 3% of the total weight, coal-water slurry apparent viscosity of 790mPa?s。The viscosity of CWS, stability studies,and determination of the apparent viscosity of CWS, Learned that the CWS dispersants has the characteristics of Humic acid Department of dispersant,that is good dispersion properties,and improve Humic acid Department of dispersant the characteristics of easy to form precipitates and formation of CWS poor performance.
  • Correlativity between pore structure parameters and thermal conductivity of cenosphere insulating refractory
    ;
    . 2012, 43(24): 25-0.
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    Pore structure parameters of cenosphere insulating refractory were changed by adjusting the content of the cenosphere additive (25%, 35%, 65% and 85%, respectively). The influence of cenosphere additions on pore structure parameters of the specimens was investigated. Based on the regression analysis and gray relational theory, the correlation of porosity and pore size distribution with thermal conductivity of the specimens was analyzed. The results showed that closed porosity of the specimens was increased significantly with increasing of cenosphere additive content; however, the apparent porosity didn’t change obviously. The range of pore size distribution of the specimens was about 1～300?m, however, the pore diameter was mainly distributed in the range of 50～100?m. In a certain temperature range, the thermal conductivity related to the total porosity by an exponent function and the dependence exponent decreased as the total porosity increased. Based on grey relation theory, the study of correlation of pore size interval with thermal conductivity indicated that the pore size interval of <150?m had the highest correlation index.
  • Magnetoelectric effect for bending modes in functionally graded ferroelectric and ferromagnetic composites
    ;Kai-Yu XU
    . 2012, 43(24): 26-0.
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    Based on the magnetostrictive phase and piezoelectric phase constitutive equations, and the method of elasticity, a static mechanical model is formulated. Assuming all physical parameters of ferroelectric and ferromagnetic material are linear or exponential function along the thickness direction, the magnetoelectric effects of a functionally graded bilayer ferroelectric ferromagnetic composite of PZT as a ferroelectric material and CoFe2O4 as a ferromagnetic material are calculated for bending deformations. Our results show that the magnetoelectric voltage coefficient can reach two peaks. When the gradient factor of material parameters of ferroelectric (or ferromagnetic) materials is negative, the magnetoelectric effect is enhanced; the magnetoelectric effect is reduced when the gradient factor is positive; the ferroelectric and ferromagnetic materials are simultaneously graded which results in the greatest magnetoelectric effect.
  • Temperature and applied field effect on ferroelectric properties of nanocrystalline BaTiO3 ceramics
    Jia LIU;; De-Jun Li ;;;Xue-Liang YANG;;
    . 2012, 43(24): 27-0.
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    100 nm is the crucial size between the micron-crystalline and the ultrafine nanocrystalline in BaTiO3 ceramics. Microstructure and ferroelectric properties have been analyzed for 100 nm BTO ceramics. Extrinsic temperature and applied field effects on ferroelectricity of BTO ceramics are studied in this paper. Different from ultrafine nano-crystalline BTO ceramics, tetragonal is the main phase; from the curves of ε-T , there is typical dispersion characteristics in orthorhombic to tetragonal phase transition, and the loss tangent (tanδ) is lower than 0.02. Moreover, the results indicated that, there is well ferroelectric hysteresis quality in BTO ceramics, with the increase of field, the energy loss density, Pr and Ec are increasing; however, ferroelectricity is reducing with the growth of temperature, when the temperature higher than Curie temperature, the ferroelectric phase shift to paraelectric phase, and there is disappearing of ferroelectric phase. Therefore, ferroelectricity is closely associated with the temperature and field.
  • Preparation and Photoelectric Properties of Ag Micro-grid Modified ITO Films
    ; ;;
    . 2012, 43(24): 28-0.
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    In this paper, the technology of polystyrene (PS) microsphere template and DC magnetron sputtering is utilized to conduct surface-modification on In2O3: Sn ( ITO ) films with the micro-grid of Ag in order to get periodic surface structure on the ITO films. This paper studies the effects of the diameter of the PS microspheres and the sputtering time on the surface morphology, transmittance in UV – Visible range, diffuse reflectance and conductive properties of the modified ITO films. Both the experiments and analyses showed that the modification of the ITO film with Ag micro-grid under the optimized conditions will improve the conductive properties of the films to the maximum of 19.5% , and its diffuse reflectance properties to 200%, with the decrease of the transmittance in visible region less than 10%, and with 2 μm diameters of polymer microspheres and 30 s sputtering time. This will help improving the light trapping effect of solar cells using ITO films as transparent electrodes.
  • Effect of rolling reduction on the texture of 6.5wt.%Si electric steel during warm rolling
    Xian-shi FANG ;;
    . 2012, 43(24): 29-0.
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    6.5wt.%Si electric steel has excellent soft magnetic properties, on which texture play important role. In this experiment, warm rolling technique was employed to investigate the effect of rolling reduction on texture. It was found that the density of {100}<110>, {110}<100> and γ-fiber textures first increased and then decreased with increasing the rolling reduction. At 75% reduction, the microstructure along the thickness of the sheet formed three zones, containing surface layer with {110}<100> orientation of refined grains, transition layer with {111}<110> and {111}<112> deformed grains, and center layer with elongated γ-fiber and {100}<110> grains. This inhomogeneity on microstructure and texture affect the development of final texture significantly.
  • Preparation and characterization of silver particles modified polyethersulfone antifouling hollow fiber membranes
    Yue Wang;Bao_li Shi
    . 2012, 43(24): 30-0.
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    Silver particles prepared by in situ reduction were used to modify polyethersulfone (PES) hollow fiber membranes for enhancing the antifouling property. Polyvinylpyrrolidone (PVP) used as dispersive agent and ethylene glycol used as reducing agent to reduce AgNO3 in the casting solution, phase inversion method was used to prepare silver modified PES hollow fiber membrane. The results indicated that the antifouling ability of silver modified PES hollow fiber membrane was stronger than PES hollow fiber; meanwhile the mechanical property of the modified PES hollow fiber membrane was improved. The initial water flux and reject rate of modified PES hollow fiber membrane were higher than PES hollow fiber membrane. The antifouling property of silver modified PES hollow fiber membrane was strongest when the PVP content was 7.5%, at the same time, the water flux was 183L?m-2?h-1, rejection rate was 94.5% and breaking strength was 2.87MPa. In this condition, the silver loss rate was only 4.7% during silver modified membrane preparation, and silver content was 4.55g per 100g membrane.
  • Immobilization Heparin/Type IV collagen onto titanium surface for improving the biocompatibility
    Kun ZHANG ;;;Junying Chen
    . 2012, 43(24): 31-0.
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    Endothelialization is a good way to obtain ultimate long-term compatibility of the interfaces between stents and blood or/and tissue. Rapid endothelialization on the biomaterials surface is possible through the aggregation, growth and proliferation of endothelial progenitor cells. In this paper, the anti-clotting drug of heparin and type IV collagen as a main component of basement membrane were combined onto the titanium surface to improve the biocompatibility. The formation of positively charged amino surface on titanium was firstly completed after alkali activation and silane treatment. The residual negative charges of heparin / type IV collagen complex were then combined to the positively charged amino surface via electrostatic interaction. The change of the groups on the surface was detected by the Fourier transform infrared spectroscopy. The water contact angle measurement and scanning electron microscopy were used to track the surface hydrophilic and hydrophobic properties and surface morphology changes. Qualitative characterization of type IV collagen and the morphology of endothelial progenitor cells were detected by immunofluorescence staining. The results showed that the bioinspired layer was successfully constructed. In compared with titanium, the bionic modified surface had more endothelial progenitor cells (EPCs) adhesion, more rapid cell growth and proliferation, and better cell morphology. It was concluded that the cell compatibility was significantly improved due to the biological modification on materials surface. The introductions of type IV collagen to materials surface provide an important pathway for the surface modification of cardiovascular implants.
  • Effects of W on the Performance of Fe-Ni Invar Alloy
    WANG Chao
    . 2012, 43(24): 32-0.
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    The element W has the properties of paramagnetic and grain refinement ability. The Expansion alloy has a low coefficient of thermal expansion (CTE) and high strength was made by W of Fe-Ni invar alloy. The sample was prepared by melting, forging and heat treatment. On the basis of Chemical analysis, metallographic and scanning electron microscopy, grain size, microhardness and CTE testing, The mechanism of performance improvement was analyzed according to the theory of magnetostrictive and metal strengthening. The result shows: the strength of matrix is improved by W alloying and the CTE is lower than that of the criteria required.
  • Selection analysis of catalytic materials in BCFNO Membrane Reactor
    . 2012, 43(24): 33-0.
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  • Effects of Ti buffer layer on the absorption characteristic and fluorescence spectrum of ZnO films
    ; ;;;;;
    . 2012, 43(24): 34-0.
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    ZnO films using different thick Ti buffer layers were deposited on Si and glass substrates by radio frequency (RF) reactive magnetron sputtering. The effect of buffer layers on the absorption characteristic and fluorescence spectrum of ZnO films was characterized by ultraviolet-visible spectrophotometer and fluorescence spectrophotometer. The results revealed that all films had an average optical transparency over 80% in the visible range, the UV absorption edge shifted to a longer wavelength after Ti buffer introduced and shifted to a shorter wavelength as the thickness of Ti buffer increased. Three main emission peaks including a UV located at about 390nm, two blue peaks located at about 435 and 487 nm and two green peaks located at about 525 and 560nm were observed from the PL spectra. The origin of these emissions was discussed.
  • Effects of Die-upset Temperatures on Magnetic Anisotropy of Nd14Fe80B6
    ;Xin-cai LIU ;PAN Jing
    . 2012, 43(24): 35-0.
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    In order to investigate the effects of die-upset temperatures on magnetic anisotropy, Nd14Fe80B6 Magnets were fabricated by MPQA power hot-pressed/die-upset process, under conditions of strain 70%, 4min and 850~880℃. As the deformation temperature is increased, the anisotropy is first improved, and then decreased. Die-upset at 870℃, the magnet with the ideal magnetic anisotropy, (006) texture, has been obtained, with (006) highest peak on the pattern of XRD, (004) poles relative density 130.01, I(006)/I(105) 1.88, and saturation magnetization 1.453T. If the belt-like microstructures with larger equiaxed grains are elimilated, and the angles between the local stay flaky grains and well orientated ones are narrowed, the (006) texture will be improved. If Nd2Fe14B equiaxed grains are changed to become flaky ones when the strain of whole magnet is not lower than 65%, (006) texture can be obtained, while the local rich-Nd phase is only favorable for grains to slip and the flaky ones to form. To refine their thickness will guarantee the magnet with both high coercive force, and high ratio between residual magnetization and saturation one. The average thickness of the grains in Nd14Fe80B6 die-upset at 850℃ is 76nm, and coercive force 450.6kA/m, and Mr/Ms 0.92.
  • Experimental Research on Mechanical Property for Stent with Micropores
    宗民 马;
    . 2012, 43(24): 36-0.
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    Through comparative tensile experiments of two kinds of stent tubes with micropores and electro polished and comparative radial strength experiments of two kinds of stents with micropores and electro polished, the results show that the deviation of mechanical properties of stent with micropores is very small in comparison with stent without micropores. This indicates that micropores structure on the stent surface almost does not have any effect on the mechanical performance of stent and proves that the stent with micropores is safe, which may help to promote the use of polymer-free stent direct drug-loading by micropores.
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