30 September 2013, Volume 44 Issue 18

    

• Select all
  |

工艺 技术
• Select
  Mechanochemical synthesis and magnetic properties of separated SmCo permanent magnetic nanoparticles

  . 2013, 44(18): 1-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Separated, single-crystal Sm2Co7, SmCo5 and Sm2Co17 hard magnetic nanoparticles with coercivities of 37.1kOe, 35.5kOe and 10.8kOe have been fabricated by mechochemcial sythesis. The influences of milling time, Sm/Co ratio of precursors and annealing process on the microstructures, phase structures and magnetic properties have been investigated. The results show that it is necessary that mechanochemical milling time was 4 h or more to obtain Sm-Co hard magnetic powders. Majority of the milled powders without annealing were non-crystal and its coercivity was low. The coercivities of the synthesized powder increased with the increase of annealing temperature and reached a maximum of 35.5 kOe when the annealing temperature was 600 oC. Then it decreased with further increasing the annealing temperature. The particle size of the synthesized Sm-Co nanoparticles deceased clearly with the decrease of annealing temperatures.
• Select
  Preparation and Optical Properties of Thermochromic VO2 thin films

  ;;;;

  . 2013, 44(18): 2-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Vanadium dioxide (VO2) thin film was deposited on quartz glass by magnetron sputtering. The plasma emission monitoring (PEM) was used to control the plasma emission intensity of vanadium during the experiment. Investigations on the structure, optical properties and phase transition performance of the films using XRD, XPS, SEM,UV-Vis-NIR spectrophotometer and Fourier infrared spectrophotometer. The results show that the VO2 films have the (011) orientation, with the width of the hysteresis loop is 25℃. A sample with balanced luminous transmittance (Tlum )and switching efficiency (ΔTsol) of the films are about 34.1% (20℃) and 35.3 %(90℃), and 6.8%(ΔTsol),respectively. At the phase transition process, the maximum variation of reflectance in infrared regions up to 44.4%.
• Select
  Preparation of Konjac superabsorbent polymer in tubular reactor

  Xiao-yang Zheng

  . 2013, 44(18): 3-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Abstract: The reactant solutions are pumped into tubular reactor by proportioning pumps. After reacting for a predetermine time in the reactor, the reaction solution is sprayed to form drops in the pressure injection device. And then, the drops complete the polymerization reaction and are dried in the continuous phase which is heated in advance. The KSAP granules are prepared in this way. The optimized products which give an absorbency of 411 and whose average diameter is 1.65 mm are obtained by the following condition. The mass ratio of cross linker and initiator to KGM is 0.29 and 0.45, respectively. The inner diameter of the tubular reactor is 4 mm meanwhile the length of the reactor is 36 m (reactive time is 25 min). The reactor is heated to 78℃. The pressure offered by the pressure injection device is 0.7 MPa. The continuous phase is polyethylene glycol-600(PEG-600). The temperature of the continuous phase is 80℃.
• Select
  Study on curing of polycarbosilane fibers using γ-ray irradiation

  Yang LI;Gao Jiao Cheng

  . 2013, 44(18): 4-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Polycarbosilane precursor fibers were irradiated byγ-ray in open air atmosphere. The irradiation curing properties were studied. Results showed that bridge structures of Si-O-Si, Si-O-C and Si-CH2-Si are formed in the fibers when irradiated in air atmosphere. Weight gain of the fibers is increased, and oxygen comsumption is decreased with absorbed dose increasing. The gel point dose is about 1.5MGy and the gelling dose is about 4.0MGy, respectively. The pyrolysis yields of the PCS fibers could be improved by irradiation. The pyrolysis yields reach up to 86.2% when the absorbed dose reached the gelling dose.
• Select
  Study on the Co77Fe2.5Mn1.4Mo2.1Si13B4 amorphous films used for low power consumption Micro-Fluxgate

  Bo GUO; ;;

  . 2013, 44(18): 5-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Co77Fe2.5Mn1.4Mo2.6Si13B4 amorphous films which used for micro-fluxgate were prepared by DC magnetron sputtering. Then the selected films were installed in a furnace and subsequently annealed in a vacuum chamber with an in-plane transverse magnetic field. The magnetic hysteresis loop, phase composition, surface appearance, and elemental composition of the films were investigated through Vibrating Sample Magnetometer, X-ray Diffraction, and Scanning Electron Microscopy. Using the prepared films as cores of a dual-core fluxgate, we tested the excitation current, sensitivity, and linear ranges of the fluxgate. The results showed that the amorphous phase was predominant, high conductivity and the hysteresis have obvious inflection point at a small magnetic field. When the films used as cores of fluxgate, we obtained obvious fluxgate signal similar with using Co-based amorphous ribbons. When working at 40 kHz, the fluxgate exhibit high sensitivity of 2700 V/T with a small excitation current 22 mA. Therefore the film material is suitable for the application in the low power consumption and high sensitivity micro-fluxgate.
• Select
  Raman spectroscopy study of In2S3:Ag thin film

  Si-Le LIN;

  . 2013, 44(18): 6-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  The phase composition and the structural characteristics of In2S3:Ag thin films were studied via X-ray diffraction and Raman spectroscopy. The samples were prepared by thermal deposition. The XRD peaks were matched to cubic In2S3 (00-032-0456). After Ag doped, the grain size of the thin film changed. The Raman spectroscopy showed the peak 232 cm-1 and 272 cm-1 had bathochromic shift, which was due to the increasing of grain size. The SEM test also supported the increasing of grain size.
研究 开发
• Select
  Adjusting and Preparation for the Microstructure of TiO2 Nanofiber

  Li Qi ming

  . 2013, 44(18): 7-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  SiO2/TiO2 composite nanofiber with one-dimensional microstructure was firstly prepared through electrospinning. Then porous TiO2 nanofiber with high specific surface area can be obtained based on hot alkaline chemical etching technique. TG analysis revealed that the organic precursor components can be completely removed above 550oC and thus pure inorganic SiO2/TiO2 nanofiber can be obtained. Meanwhile, it was found that TiO2 phase transition from anatase to rutile can be effectively inhibited by the doping of SiO2 into the bulk of TiO2. Hence, highly crystallized rutile TiO2 can be gotten at 700oC. SEM characterization showed that most SiO2 can be successfully etched from the bulk of SiO2/TiO2 composite nanofiber and thus high-quality porous TiO2 nanofiber can be formed. Compared with the nanofiber without any treatment, porous TiO2 nanofiber exhibited higher specific surface area and better microstructure.
• Select
  Preparation and Dielectric Properties of Graphene Nanosheets／Epoxy Composites

  Xiao-Qin GUO

  . 2013, 44(18): 8-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Graphene nanosheets (GNSs) with few-layer graphene have been prepared from natural flake graphite by oxidation intercalation and microwave expansion. Then GNSs was modified by silane coupling agent KH-560. GNSs/ EP composites was finally prepared by the ultrasonic mixing method. The structure and morphology of the samples were characterized by FT-IR and SEM. The dielectric properties of the composite was tested by impedance analyzer. The results show that the permittivity increases with the rise of GNSs content to the maximum when GNSs content get to 0.3wt.%, and then decreases. The effect of GNSs content on dielectric loss is the opposite. Modified GNSs / EP composite has a higher permittivity and lower dielectric loss compared with GNSs / EP composite.
工艺 技术
• Select
  The study of the preparation and the heating treatment of NiFeCr/NiFe/MgO/Ta films

  Ming-Hua LIWei Li;;

  . 2013, 44(18): 9-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  The NiFeCr(45?)/NiFe(100?)/MgO(40?)/Ta(50?) films were prepared by magnetic sputtering and were annealed in a vacuum furnace with an applied plane field. The anisotropic magnetoresistance (AMR) increases dramatically after the annealing and it reaches to 3.02% after annealing at 400℃. Afterwards, the AMR decreases with a further increase of the heating treatment temperature. The XRD results show that the perfect diffraction peak of NiFe(111) is well presented. At the same time the MgO(111) is presented also and the intensity of the MgO(111) decreases with the increase of the heating treatment temperature.
• Select
  Fabrication of gradient WC-Ni cemented carbide materials by high-gravity-assisted combustion synthesis and infiltration

  ;;Shi-Bin GUO;

  . 2013, 44(18): 10-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Gradient WC-Ni cemented carbide materials were prepared by high-gravity-assisted combustion synthesis and infiltration, where Ni melt was in-situ synthesized and then infiltrated into porous compacts of WC powder. The obtained materials consisted of two layers and showed a gradient feature along the high-gravity direction, in which the upper layer was Ni metal and the under layer was WC-Ni cemented carbide. The hardness of the Ni metal and WC-Ni cemented carbide reached 72 HRA and 87 HRA, respectively. The agitation of Ni melt during infiltration resulted in the presence of WC particles in the Ni metal and growth of WC grains in the cemented carbide layer. The WC-Ni cemented carbide materials showed a relatively low bending strength of 770 MPa, which may be connected with the down-to-up solidification kinetics.
• Select
  Effect of Al doped on Microstructure and Properties of TiN Coating

  Yong-Yao SU ;;;

  . 2013, 44(18): 11-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Abstract: Al-TiN coating deposited on high speed steel by plasma enhanced magnetron sputtering ion plating and evaporating deposition combination sources equipment. Study on the effect of little Al doped on the microstructure and mechanical properties of TiN coating. The elements, phase structure, film-substrate cohesion and microhardness were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), microhardness meter; the wear resistance was investigated with CSEM pin- on- disk wear test apparatus and step profiler. The results show that the addition of little Al make the film-substrate cohesion and wear resistance are evidently improved.
综述 进展
• Select
  Development of the exchange bias in NiMn-based ferromagnetic/antiferromagnetic films

  Xuan PAN;Guang-Hong ZHOU

  . 2013, 44(18): 12-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  The NiMn alloy film, as a kind of high performance anti-ferromagnetic materials, has an important application prospect in the giant magnetoresistance devices, which attracts more attention by the scientists in the field of physics and materials science. Firstly, this paper reviews the basic properties of NiMn alloy film; then some characteristics of exchange bias in the ferromagnetic/antiferromagnetic bilayers based on NiMn alloy are systemic analyzed.
• Select
  Progress in Bismuth Molybdenum Composite Oxide

  ;

  . 2013, 44(18): 13-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  In this work, a variety of the preparation methods of bismuth molybdenum composite oxides have been summarized, such as solid state reaction, precipitation, sol-gel, hydrothermal method, spray-drying and so on. The advantages and disadvantages of these methods were also commented. Then, the application of bismuth molybdenum composite oxides were introduced, including oxidation catalysts, photocatalysts and electrolyte material, as well as the effect of structure, morphology, composition on the properties of materiel. The development direction of the preparation techniques, the components and the structure and morphology were pointed out, in view of its application filed.
研究 开发
• Select
  INFLUENCE OF THE DIFFERENT MODULI IN TENSION AND COMPRESSION ON THREE-POINT BENDING OF ALUMINUM FOAM SANDWICH PANELS

  ; ;

  . 2013, 44(18): 14-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Abstract: Aluminum foam is a typical bimodulous material with different elastic moduli in tension and compression. The three-point bending behaviors of sandwich panel were simulated using ABAQUS FEA software. The crushable foam material constitutive model was used to simulate aluminum foam core, and the different elastic moduli were adopted in tension and compression zone to study the influence of the elastic moduli. Furthermore, the void model with bimodulous character was used to simulate the three-point bending response of aluminum foam sandwich panels. Based on the same monotonic compression response of aluminum core, the simulated results of void model were compared with that of crushable foam model without bimodulous character. It is shown that the elastic moduli of aluminum foam core has a great influence on the three-point bending behavior of aluminum foam sandwich panels. If the bimodulous effects of aluminum foam is neglected, the simulated loading stiffness and yield load are obviously on low side for the three-point bending behaviour of aluminum foam sandwich panel.
• Select
  Properties of Magneto-rheological Fluids based on Hollow Cobalt Micro-particles

  ;Xu-Feng DONG; min qi

  . 2013, 44(18): 15-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Cobalt particles were prepared by hydrothermal method. Their composition, morphology, and magnetic property were analyzed by using X-ray diffractometer, scanning electron microscope, and vibrating sample magnetometer, respectively. The results indicate the composition of the particles is pure cobalt with close-packed hexagonal structure. The particles present hollow structure with particle size distributed in the range of 3 to 5 micrometers. The saturation magnetization of the particles is 161 emu/g, which is close to that of carbonyl iron particle (CIP). Magnetorheological (MR) fluids were prepared with the hollow cobalt particle (HCP), the volume fraction of which was 12%, and silicone oil. Their properties were tested, the results of which indicate that the MR fluids present a field-induced yield stress of 37 kPa. Their shear stress stability with time at constant shear rate, and sedimentation stability during long time standing was better than that of the MR fluids based on carbonyl iron particles with the same volume fraction.
• Select
  Synthesis and Application of Waterborne Polyurethane Adhesive Modified With Sulfonic Groups

  ;Xiao-rui Li ;

  . 2013, 44(18): 17-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Waterborne polyurethane prepolymer were synthesized by a prepolymer process using dimethylol propionic acid (DMPA) and 2,4-diamino-benzenes sulfonic acid sodium salt(SDBS) as hydrophilic chain extender agent. And the sulfonic polyurethane adhesive emulsion with solid content of 50% was obtained when emulsified with the mixture of ethylene-vinyl acetate copolymer（EVA）and deionized water. The structure of the film was confirmed by means of Fourier transform infrared spectroscopy (FTIR). The results indicated that the SDBS has been successfully introduced into the polyurethane chain. The influence of the SDBS content on the primeval peel strength , heat resistance and stability of the adhesive emulsion and films were studied．The results show that when SDBS content increases from 0% to 2.5%，the primeval peel strength increases from 20.98N to 89.23N，heat resistance and stability of the adhesive emulsion and films also increases. Transmission electron microscope(TEM) photos show that SWPU emulsions emulsified with EVA dispersed well with neat appearance.
• Select
  Effect of Stibium on Microstructure and Properties of Mg-3Sn-1.5Al-1Zn-1.2Si Magnesium Alloy

  Jian-Xin ZHANG

  . 2013, 44(18): 18-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  The effects of Sb on microstructure and mechanical properties of Mg-3Sn-1.5Al-1Zn-1.2Si magnesium alloy were studied when Sb was added into melt in the form of pure metal with the range of 0-1.8% (mass fraction, similarly hereinafter). The results demonstrate that Sb element and Mg matrix preferentially combine to form Mg3Sb2 phases, the addition of 1.0% Sb has a strong modification for Chinese script morphology Mg2Si phases. Sn can replace Si of Mg2Si then form Sn-rich Mg2(Si,Sn) compound phase, whose physical properties lie between Mg2Si and Mg2Sn. With the increase of Sb content, the elongations of as-cast and extruded alloy decrease, and tensile strengths increase firstly and then decrease, a best combination of strength and plasticity is 1.0% or so. The increase of Sb is beneficial to improve the heat resistance of Mg-3Sn-1.5Al-1Zn-1.2Si alloy.
• Select
  Effects of terminal group of silicone oil on properties of oxalate group-modified amorphous titanium oxide nanoparticles-based electrorheological fluids

  Xu-Feng DONG;; min qi ;;

  . 2013, 44(18): 19-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Electrorheological (ER) fluids were fabricated by dispersing oxalate group-modified amorphous titanium oxide nanoparticles in silicone oil with similar viscosity but different terminal groups （hydroxyl, hydrogen, and methyl）. The yield stress, zero-field viscosity, ER efficiency, leak current density, shear stability and sedimentation stability was tested to find the influence of the terminal group of silicone oil on properties of ER fluids. The results indicated that the ER fluids based on the silicone oil with polar terminated group presents improved yield stress, higher ER efficiency, and better sedimentation stability, but larger leakage current density, while the ER fluids based on the silicone oil with small terminated group presents higher yield stress, higher ER efficiency, and less leakage current density, but worse sedimentation stability.
• Select
  Study on the preparation of cadmium telluride powder by liquid-phase reduction and hydrogen treatment

  ;;

  . 2013, 44(18): 20-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  The uniformly mixing precursor powders at nanoscale size was prepared by in-situ reaction which used cadmium chloride and tellurium dioxide as raw materials, and hydrazine hydrate as a reducing agent and a complexing agent. The cadmium telluride was obtained by hydrogen reduction of precursor powders during 110～400°C. Moreover, the evolution of phases and microstructures were investigated by XRD, TG, SEM etc. The results show that during the preparation of precursor the tetravalent tellurium was changed to elemental tellurium at nanoscale size, while the ions of cadmium precipitated in the form of 2 ~ 5μm Cd(N2H4)xCl2 complexes. Furthermore, the elemental tellurium and Cd(N2H4)xCl2 dispersed uniformly. The single phase cadmium telluride can be obtained from the precursor treated by hydrogen at 400℃ and the precursor was prepared with cadmium chloride and tellurium dioxide mixed with a molar ratio 1:1.
• Select
  Synthesis of KH550 crosslinking Modified Solvent-free Polyurethane/Polyacrylate Emulsion

  ;Yi-ding SHEN ;

  . 2013, 44(18): 21-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  A series of Solvent-free anionic polyurethane/polyacrylate modified by KH550 were prepared by in-situ polymerization.The influence of content of KH550 on properties of the WPUA emulsion and its film’s property were systematically studied. The structure and related application performance of the WPUA emulsion was analyzed by Fourier Transform Infrared(FTIR),Thermogravimetry Analysis(TGA),Dynamic Light Scattering Instrument(DLS),Atomic Force Microscope(AFM),water absorption test. The results show that KH550 reacted with –NCO of polyurethane.Furthermore,the average particle size of the WPUA emulsion was 104.5 nm and the film was endowed with excellent thermal stability when w(KH550)=1.05%.Additional, the film was endowed with flat and regular coating surface, the pencil hardness of the film reached 2H,adhesive force grade reached the 0 level,and the water absorption was 8.57%,the impact resistance was up to GB/T1732-93.
• Select
  synthesis of Iodine butyl - dimethoxy dibenzyloxyphosphoiyl propionamide polysiloxane and its water repellency and flame retardancy on cotton fabric

  Chao-hong DONG;Zhou LV;Ping ZHU

  . 2013, 44(18): 22-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Abstract: Reactive Iodine butyl-co-N-methoxy-3-(dimethoxy dibenzyloxyphosphoiyl) propionamide polysiloxane〔（IB-co-N-MDPA)PDMS）〕 with double functions of water repellency and flame retardancy was synthesized using N - methylol - 3 - (dimethoxy dibenzyloxyphosphoiyl) acrylic amide, sodium hydroxide and poly[(4-iodo-n-butoxy)methylsiloxane] as raw materials. The structure of （IB-co-N-MDPA)PDMS was characterized by the FT-IR and 1H NMR. It can be combined with cotton by covalent bonds. The morphology, thermal properties, flame retardency and flame retardent mechanism of the multifunctional cotton fabric were analyzed using TGA and Limit Oxygen Index (LOI) instrument. The contact angle and water repellency of it were tested. The results showed that（IB-co-N-MDPA)PDMS reacted with cotton fiber to form crosslinked membrane on the surface, which had water repellency function. And also the coexistence of silicon, nitrogen and phosphorus could produce synergistic flame-retardant effect.
• Select
  Studies on preparation and adsorptive properties of thermo-sensitive D-naproxen molecularly imprinted hydrogels

  ;zhao yi ping ;;;

  . 2013, 44(18): 24-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  A novel thermo-sensitive D-naproxen (D-Npx) molecularly imprinted hydrogels (MIH) was prepared by thermal polymerization with D-Npx as the template molecule, N-isopropylacrylamide as functional monomer, N,N'-methylene- bis-acrylamide and ethylene glycol dimethacrylate as cross-linking agent, respectively. The thermo-sensitivity and the influences of the cross-linking agent on structure and separation performance of the hydrogels were investigated. The results showed that the equilibrium swelling ratio of MIH decreased with the increase of the concentration of MBAA, and adsorption and desorption amount of D-Npx increased firstly and then decreased. The adsorption and desorption amount of D-Npx increased continually with the increase of the concentration of EGDMA. MIHs exhibit obvious thermo-sensitivity. The concentration of MBAA had little effect on the lower critical solution temperature (LCST) of the hydrogels, and MIHs exhibited excellent reverse swelling-deswelling property, the maximum of desorption amount of D-Npx could reach up to 90%.
• Select
  Synthesis and properties of sulfonated poly(phthalazinone ether sulfone) containing pendant phenyl groups as proton exchange membrane materials

  shouhai zhang ;;

  . 2013, 44(18): 25-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  A series of poly (phthalazinone ether sulfone ) containing pendant phenyl groups (PPES-P) were synthesized from 4-(3-phenyl-4-hydroxyphenyl)-2,3-phthalazin-1-one, 4-(4-hydroxyphenyl)-2,3-phthalazin-1-one and 4,4'-dichlorodiphenyl sulfone. Sulfonated poly (phthalazinone ether sulfone) containing pendant phenyl groups (SPPES-P) were prepared from PPES-P with concentrated sulfuric acid as the sulfonating agent. The ion exchange capacity(IEC) of SPPES-P was obtained by titration method and theoretical calculation. The chemical structure of PPES-P and SPPES-P were characterized with 1H-NMR and FI-IR. SPPES-P proton exchange membranes with different IEC values were prepared. SPPES-P membranes exhibited moderate water uptake and low swelling. SPPES-P membranes showed high oxidative stability and low methanol permeability. The methanol permeability values of SPPES-P membranes ranged from 7.34×10-8 cm2?s-1 to 1.2×10-7 cm2?s-1, which were much lower than that of Nafion117 membrane (1.04×10-6 cm2?s-1) under the same test condition. The proton conductivities of SPPES-P membranes increased with the increase of IEC and temperature. The proton conductivity of SPPES-P100 membrane reached 1.4×10-2 S?cm-1 at 95 oC.
• Select
  Effect of powder size on coating microstructure of high-aluminum bronze by supersonic plasma spraying

  ; ;;;

  . 2013, 44(18): 26-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Took 45 steel as the matrix, high aluminum bronze alloys coatings were prepared by S-APS with four different particle sizes powders, which were -280 ~ + 320 meshes, -320 ~ +360 meshes,-360 ~ +400 meshes and -400 meshes. The phase composition, microstructure, microhardness were analyzed by means of XRD and SEM. The results shows that the powder particle sizes have an important influence on the coating structure and performance. The smaller powder sizes are, the better the coatings structure and performance are. The coating prepared by the - 400 meshes powders has dense and homogeneous organization, obvious laminar structure characteristic .The average hardness of the coating of - 400 meshes powders reaches 367.5HV.
• Select
  The study on in vitro degradation of bilayer spider silk protein vascular scaffold

  Liang ZHAO;;;

  . 2013, 44(18): 27-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  The preparation of vascular scaffold becomes a necessary condition for cure for cardiovascular disease. In this paper electrospinning technique was used to prepare the (pNSR16/PCL/CS)/(pNSR16/PCL/Gt) bilayer vascular scaffold, and its degradation in vitro was studied after being soaked in phosphate buffer solution ( pH 7.14 ) and multiple enzyme solution for different time. The changes of weight loss rate, water absorption rate, pH value of degradation solution, mechanical property and molecular weight were tested after sampling at 2nd, 4th, 8ht, 12th week respectively, and at the same time the morphology was observed using scanning electron microscope. The results showed that:the initial bending strength and molecular weight of (pNSR16/PCL/CS)/(pNSR16/PCL/Gt) bilayer vascular scaffold were greater than those of (PCL/CS)/(PCL/Gt), the degradation velocity and decreasement velocity of molecular weight and weight loss rate of the former were faster than the latter, and the addition of pNSR16 promoted the degradation of vascular scaffold. In the process of degradation, pH value of degradation solution was weakly acidic and neutral, the scaffold decreased rapidly in in the prophase and showed stable trend in the late period. The degradation speed of scaffold in the enzyme solution was faster than it in the hydrolysis soultion.
• Select
  Preparation of Low Resistivity Tantalum Film Deposited by Magnetron Sputtering

  ; ;

  . 2013, 44(18): 28-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Tantalum films deposited on silicon substrates by DC magnetron sputtering at different sputtering pressure and sputtering power, which were prepared in pure Argon at room temperature without underlayer, have been studied. The film resistivity, crystalline phase and surface morphology were investigated with Four Point Probe, X-Ray diffraction and Atomic Force Microscope. The results showed that the film resistivity increased due to the appearance of tetragonal crystalline structure (?-phase) with increasing the sputtering pressure. Under the same sputtering pressure, the film resistivity first decreased and then increased when the sputtering power gradually increased. Lowest film resistivity which was 29.7???cm, has been obtained at an optimized condition.
• Select
  Controlled Preparation and Properties of Flaky alumina for White LEDs

  . 2013, 44(18): 29-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Light Emitting Diode( LED) has been widely applied in the field of lighting and displaying. Flaky Alumina Powders was synthesized using aluminum nitrate and urea as the raw materials, PEG 2000 as the surfactant and aluminum fluoride as the additive. The YAG∶Ce3+ phosphor was synthesized with Flaky Alumina by the method of hydrothermal-pyrolysis. The structure and morphologies of the synthesized samples were investigated by XRD, SEM and FM techniques. The results showed that after 24 hours’ thermal reaction at 120℃, by adding appropriate amount of aluminum fluoride, regular hexagon tabular alumina with particle size of 3-4μm and thickness of 0.2-0.3μm can be obtained through high-temperature calcination.The additive aluminum fluoride plays an important role in controlling the particle size of the alumina. This study explores the application of the flaky alumina powders, which is synthesized by the method of hydrothermal-pyrolysis and served as the base LED phosphor powder, in the phosphor powder YAG: Ce3+.and obtains optimized results．
• Select
  Purification of Motor Vehicle Exhaust Gas by Perovskite Catalyst based on the Porous TiAl alloys

  Fan YANG ;;;

  . 2013, 44(18): 30-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  In this work, Ti-48Al-6Nb porous alloys were fabricated by powder sintering and the structure and three-way catalytic property of a perovskite catalyst were evaluated. The skeletons of porous alloys consisted of α2 and γ phases, and the porosity is 39.5%. After successful compose with the LaMnO3 catalyst, elements Sr and Pd were doped into B site. In addition, a few Pd elements could replace the ion in B site and go into the perovskite lattice, resulting in reducing the ignition temperature and improving the catalytic conversion efficiency at great extent.
• Select
  Effect of Ni addition on glass forming ability and soft magnetic properties for FeZrNbB alloys

  Mu-Zhu CHEN

  . 2013, 44(18): 31-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Abstract: Amorphous Fe(86-x)Zr2Nb2B10Nix (x=0,1,3,5) alloy ribbons were prepared by the single roller melt-spinning method. The effect of Ni addition on glass forming ability and magnetic properties of FeZrNbB alloy ribbons was investigated by X-ray diffraction (XRD), differential scanning calorimeter (DSC), vibrating sample magnetometer (VSM) and precision magnetics analyzer. It was found that the glass foming ability is improved and the first crystallization onset temperature (Tx1) increase with increasing Ni addition. The α-Fe phases with grain size (D) of 12nm precipitated from alloy ribbons doped Ni, which had a lower Hc of 8.1 A/m. The results of Fe85Zr2Nb2B10Ni1 ribbons annealed at 510℃ for 20min showes a higher Bs of 1.61T, effective permeability (μe) of 48.4k, and coercivity (Hc) of 8.3A/m.
• Select
  Crystallization behaviors of (Na0.85K0.15)0.5Bi0.5TiO3 ferroelectric thin films prepared by a sol-gel route

  ;Han-Fei ZHU

  . 2013, 44(18): 32-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  Lead-free (Na0.85K0.15)0.5Bi0.5TiO3 (NKBT) ferroelectric thin films were successfully deposited on (111)Pt/Ti/SiO2/Si substrate using a sol-gel route. The crystallization behaviors and the surface morphology of NKBT films were characterized separately by XRD and AFM. It was found that, within a certain temperature range, the crystallinity of films were more and more complete with the increase of pyrolysis temperature and annealing temperature, and the grains became more uniform and dense. The film pyrolyzed at 450°C and annealed at 700°C exhibited optimal crystallinity, the good ferroelectric properties with a remanent polarization of 10.37μC/cm2 and a coercive field of 78.2kV/cm for NKBT film were achieved.
• Select
  Study on Synthesis, Characterization and Mechanism of Carboxylated Collagen Fiber

  ; ;Longfang Ren

  . 2013, 44(18): 33-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  The carboxylated collagen fiber (CCF) was prepared by modifying collagen fiber (CF) with glyoxylic acid. The contents of amino and carboxyl of CF and CCF were measured by chemical analysis methods, and the isoelectric point of CF and CCF was determined by Ze-ta potential analyzer. The results indicated that the amino content decreased by 69.23% while carboxyl content increased by 52.77% after modification, and the isoelectric point from 6.91 down to 5.45. The result of surface area and porosity determination showed that the acetaldehyde acid modification can effectively increase the specific surface area and reduce the porosity of the collagen fiber. Furthermore, the form, structure and thermal properties of CF and MCF were characterized and analyzed by SEM, FTIR and DSC respectively. Finally, the reaction mechanism between aldehyde acid and collagen fiber was studied by means of collagen molecule modification and amino acid analysis.
• Select
  Solvothermal Synthesis of amino-doped graphene and its Electrochemical behavior on ascorbic acid

  ;Min LUO ;;;

  . 2013, 44(18): 34-0.

  Abstract ( ) Download PDF ( ) Knowledge map Save

  N-doped graphene was synthesized by on-pot solvothermal process in the mixed solution using ethylenediamine and graphene oxide (GO) as precursors. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) were utilized to characterize structure and electrochemical behavior of the as synthesized N-doped graphene. The organic amine is not only as reductant to remove the oxygen-containing groups (OCGs) in the graphene oxide, but also as nitrogen sources to obtained the N-doped graphene. The EIS revealed the electron transfer impedance of the N-doped graphene is obviously lower than graphene, indicating that the introduction of nitrogen-containing groups remarkably improve the electrical conductivity. The obtained N-doped graphene was also applied to electrochemical determination of ascorbic acid. The detection limit was found to be 1.7×10-7mol/L. This demonstrated the material is of excellent electrocatalytic property.