31 October 2014, Volume 45 Issue 20

    

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工艺 技术
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  Influence of coarse aggregate angularity on open-graded friction courses’ performance

  Li-Qun HU ;

  . 2014, 45(20): 1-0.

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  In the paper, 12 kinds of Open-graded Friction Courses（OGFC）mixtures were prepared according to the gradation of OGFC-10, OGFC-13 and OGFC-16, the coarse aggregates used in the OGFC mixture were worn in different degree by using Los Angeles abrasion machine. Then coarse aggregate angularity composite values (Ic) of 12 OGFC mixtures were got by using aggregate imaging measurement system and the road performances of these OGFC samples were tested. The results showed that when the aggregate gradation of the OGFC mixture are the same, the Marshall stability, dynamic stability, porosity and skid resistance performance of OGFC decreased along with the decrease of coarse aggregate angularity value significantly, but the permeability performance of these OGFC change slightly. When the aggregate gradation of the OGFC mixtures are different, Marshall stability, dynamic stability and skid resistance performance of OGFC-16 and porosity of OGFC-10 decreased obviously along with the decrease of coarse aggregate angularity composite values (Ic).
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  Influence of temperature on the performance of magnetorheological fluid

  Fei CHENZu-Zhi TIAN

  . 2014, 45(20): 2-0.

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综述 进展
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  Progress of High Thermal Conductivity and Low Expansion Composite Silicone Rubber and Thermally Conductive Filler

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  . 2014, 45(20): 3-0.

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  Advances in the high thermal conductivity and low expansion rate silicone rubber and thermally conductive filler were summarized. First, the common thermally conductive filler and basic properties of thermally conductive filler were introduced, including metals, oxides, nitrides, carbides, etc.. And the performance characteristics of various types of thermally conductive filler was described in detail and pointed out the influence of the basic performance of the thermal conductivity on thermal conductivity, including filler ratio, size, size distribution, shape and surface properties of the filler and so on. Followed by a detailed description of the basic ways to improve thermal conductivity were given, including introduction of thermal conductivity mechanism; matrix materials research; development of new high-performance thermally conductive filler; conduct thermally conductive filler surface modification; silicone rubber molding process optimization, etc.. Then some basic ways to reduce the coefficient of thermal expansion were introduced, including modification of inorganic nanoparticles and so on. Finally, some of the basic problems acurrently existing in the field and some ideas of solutions were advanced and the development trends were prospected.
研究 开发
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  Magnetic dynamical properties of exchange-coupled soft/hard magnetic bilayer systems

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  . 2014, 45(20): 4-0.

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  The magnetic dynamical properties of exchange-coupled soft/hard bilayer structure are investigated in the framework of a one-dimensional atomic chain model based on the Landau-Lifshitz equation. The frequencies and the spatial distribution characteristics of the spin wave eigenmodes are calculated for the uniform magnetic structure before reversal and the spiral magnetic structure during exchange-spring process. The spin wave dispersion relation is obtained. It is found that the magnetization reversal mechanism is closely related to soft mode of spin wave. The magnetization reversal of the soft layer is induced by softening of the first-order spin wave mode, and reversal process is determined by the spatial distribution of the soften mode. The critical fields determined from the magnetic properties are in good agreement with the result of analytic solution.
工艺 技术
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  Investigation on preparative technology and microstructure of Fe-Al mixture with rich aluminum by hot-pressing sintering

  Qiang LI; ;

  . 2014, 45(20): 5-0.

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  Abstract: Hot-pressing sintering process was performed on Fe-Al mixture to fabricate alloy specimens. Intermetallic compounds sintered with different pressure and temperatures were analyzed by X-ray diffraction (XRD) and energy disperse spectroscopy (EDS), and the microstructure was investigated with scanning electron microscopy (SEM). The results show that the critical temperature which compounded Fe2Al5 in pressure of 10MPa was 550℃, and the product was FeAl3 instead with pressure of 20MPa.The simple substance iron could be coated gradually by compounds of rich aluminum with the increase of pressure, which obstructed the diffusion. For keeping the energetic feature of sintering body, the Sintering temperature and pressure should be controlled at 600℃ and 10Mpa. The study results provided a reference for processing Fe-Al mixture with rich aluminum by Hot-pressing sintering.
研究 开发
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  Preparation of metal Co from Co3O4 by the SOM method

  Shan Lin GU;;

  . 2014, 45(20): 6-0.

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  Metal cobalt has been widely studied and applied because of its special physical and chemical properties. In this paper, the preparation of cobalt direct from cobaltosic oxide by the solid oxygen ionic membrane (SOM) method has been studied. The influences of the pressed pressure, sintering temperature and electrolysis time on experiment have been investigated. The results show that the porosity of the Co3O4 pellet decreases with increasing the pressed pressure and sintering temperature. Furthermore, the particle size of the electrolysis products decreases with the increase of the pressed pressure. 2 g Co3O4 pellet pressed under 10 MPa and sintered at 900 °C for 4 h can be electrolyzed to pure Co within 2 h at 1000 °C and 4 V.
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  Modification of Polypropylene Separator by Graft Crosslinking Copolymerization of Divinylbenzene and Methyl Acrylate

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  . 2014, 45(20): 7-0.

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  This study was about the surface modification of PP separator by introducing crosslinked divinylbenzene(DVB)/methyl acrylate(MA) to increase its thermal dimensional stability. The total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used to prove that the copolymerization of DVB and MA did occur on the surface. The influences of reaction time, reaction temperature, concentration of initiator on the grafting ratio and thermal properties of PP separator were explored. Furthermore, KH570 was introduced onto the surface by the copolymerization of DVB and KH570 double bonds，by which the SiO2 particles were also introduced. The pore structure was observed by SEM. The thermal shrinkage of modified separator reduced a lot than before. The shrinkage at 130℃ reduced from 12% to 4% in 4h.
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  Theoretical research of SrO adsorption on GaN(0001) surface

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  . 2014, 45(20): 8-0.

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  The adsorption of SrO on GaN (0001)2×2 surface is theoretically calculated employing the density functional theory within a plane-wave ultrasoft pseudopotential scheme. The adsorption orientation, the adsorption energy, and the bonding characteristics of SrO molecule are studied. The simulated results show that SrO adsorbs on GaN(0001) surface mainly in the form of undissociated molecule and the most stable position of SrO on surface is at the bridge site of Ga, and the chemical bonding energy is achieved to be 7.257—7.264eV. The charge population and PDOS reveal that the chemical bonding of Ga—O shows a covalent bonding property. After adsorption, electrons of SrO transfer to part Ga atoms of the GaN(0001) surface, and the surface exists still the surface state.
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  Stable Dispersion of Detonation Nano-diamond in Base Oil

  Hong Xiao WANG;Jun Wang

  . 2014, 45(20): 9-0.

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  Research on the flexural properties of SBR latex modified cement concrete

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  . 2014, 45(20): 10-0.

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  The effects of styrene butadiene latex on the ratio of compressive strength to flexural strength, deflection at max bending load and flexural toughness are investigated. The results showed that the latex content increased from 0 to 60%, the flexural strength and flexural toughness coefficient of modified concrete first increased and then decreased, the flexural strength and flexural toughness coefficient reached the max value of 7.54MPa and 2.029MPa when latex content was 17% and 19%. The max bending load deflection increased linearly with the latex content increased from 0 to 60%. Considering the high cost of SBR latex and the properties of the modified concrete, the content was suggested about 13%~15%. When the latex content ≤ 21%, the ratio of compressive strength to flexural strength decreased exponentially and the deflection at max bending load increased linearly with the increase of flexural toughness coefficient. The deflection at max bending load can characterize the flexural toughness coefficient more precisely.
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  Pretreatment of QF with terminalalkynes-containg silane coupling agent and properties of their PSA composites for wave-transmitting applications

  Yu GE

  . 2014, 45(20): 11-0.

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  Abstract: A novel silane coupling agent (AG-2) containing terminalalkyne groups was synthesized and introduced to promote the interfacial bonding performance of QF/PSA composites. The interactions among the coupling agent, resin and matrix were characterized. FT-IR and 1H-NMRspectra indicated the well preparation of AG-2. Gelation time and TGA analysis showed that heat-resistant performance of PSA was hardly influenced by AG-2.TGA, XPS, SEM and surface energy analyses inferred effective chemical bonds formed between fiber surface and AG-2 as well as the resin and AG-2.The surface energy of QF increased which made interface matched. Significant enhancement of ILSS and Flexural Strength of modified composite had been achieved and promoted by 34.77% and 38.30% compared to those unmodified.
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  Bifunctional ionic liquid as template in the preparation of mesoporous silica via a sol-gel method

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  . 2014, 45(20): 12-0.

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  A novel bifunctional ionic liquid 1?methyl?3?(3?sulfopropyl)?imidazolium n-dodecayl sulfonate ([PMIM(SO3H)][C12SO3]) was conveniently synthesized, and the structure was determined by FT?IR, 1H NMR and 13C NMR, respectively. Furthermore, mesoporous silica was prepared from ethyl silicate (TEOS) as silica source and the obtained ionic liquid as acid source and template by traditional sol?gel methods. The formation of the mesoporous material was characterized by TGA and FT?IR. Several methods such as SAXRD, SEM, TEM and nitrogen adsorption?desorption isotherms were employed to characterized the morphological structure and properties of mesoporous silica. The experiment on Pb2+,one kind of heavy metal ion, adsorption was applied so as to detect the property of the material. The resultant mesoporous silica material exhibited the specific surface area of 1010 m2/g, the pore volume of 0.95 cm3/g and the average pore diameter size of 3.25 nm, respectively, while the mesoporous silica has a good adsorption property for heavy metal ion of Pb2+.
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  Research on Stability of Al2O3-EA Nanofluids in Mild and Low Temperature Environment

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  . 2014, 45(20): 13-0.

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  Abstract: Non-electrolyte ethanol absolute (EA) based Al2O3 nanofluids with 1% concentration were prepared by double step method without addition of any surfactants or dispersants. Influence of temperature change on stability of EA based Al2O3 nanofluids were researched in mild and low temperature environment. Nanofluids stability was appraised by UV-light analyzer. Size distribution and Zeta potential of nanoparticles were measured as well. Sedimentation velocities of nanoparticles were calculated by pre-existed formula. Functions of particle size distribution and sedimentation velocity variation with time change at different temperatures were built by statistics fitting method. Energy barrier variation was applied to analyze experimental phenomenon theoretically. The experimental results demonstrated that nanofluids maintain more stable at low temperature environment.
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  Preparation of PTF-sensitized TiO2 hollow microspheres and visible-light catalytic properties

  ;Bing-hua YAOWeng Zhang;;

  . 2014, 45(20): 14-0.

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  Using polymethyl methacrylate (PMMA) microspheres as template, the TiO2 hollow microspheres (h-TiO2) were prepared by hydrothermal method. The 9-phenyl-2,3,7–trihydroxy-6-fluorone (PTF) used as sensitizer, the h-TiO2 hollow microspheres were dye-sensitized by using immersion method, and a novel dye-sensitized TiO2 hollow microspheres (PTF-h-TiO2) was successfully synthesized. The morphology and structures of samples were characterized by the SEM, XRD, FT-IR and UV-vis DRS. The effects of the parameters such as hydrothermal time and temperature, addition amount of template and calcination temperature on the photocatalytic activity of samples were investigated respectively. The optimum synthesis condition of the h-TiO2 preparation was obtained to be the 5% addition amount of template, hydrothermal time of 6 h, hydrothermal temperature of 120°C. The photocatalytic activities were also evaluated by degradation of methylene blue(MB) and chloramphenicol(CAP) under UV visible-light. The results showed that the h-TiO2 photocatalyst possessed UV-visible photocatalytic activity, and the PTF-h-TiO2 photocatalyst exhibited excellent visible-light catalytic activity. The degradation rate of as-prepared PTF-h-TiO2 is quit high, up to about 98.1% in 50min for 10 mg/L MB solution, and about 86.9% in 120min for 20 mg/L CAP solution under Xe lamp irradiation (>400nm).
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  Synthesis and properties of polyimide aerogels

  yiren chen

  . 2014, 45(20): 15-0.

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  Polyimide sol were prepared based on the ODA ,ODPA and crosslinker TAB in NMP, polyimide aerogels were obtained via supercritical CO2 drying. Study on the effects of sol formula and density ,shrinkage, porous structure, BET surface area, tensile strength, and thermal conductivities of polyimide aerogels,to prepared low density,small pore diameter, high BET surface area, low thermal conductivity aerogels.
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  Influence of particle shape on the magnetic properties of Fe-35wt%Co alloy absorber

  . 2014, 45(20): 16-0.

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  Abstract: The water atomized Fe-35wt%Co soft magnetic alloy powder was milled by high-energy milling method. Variations of the morphology, static magnetic parameters and microwave complex permeability within 2~18GHz with different ball milling times for the alloy powder were investigated using SEM ,VSM and vector network analyzer, respectively. The results show that the alloy powder particles can be flattened after ball milling, so that the real and the imaginary parts of its complex permeability are significantly improved; With the increase of milling time, the saturation magnetization of the milled powder decreases while coercivity increases ,the aspect ratio and the real and imaginary parts of the complex permeability all show the tendency of increasing first and then declining, which suggests that overmilling will deteriorate the performance of soft magnetic alloy powder, and is not conducive to the improvement of microwave permeability.
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  Effects of air-entraining agent on electromagnetic wave reflectivity and transmission rate of the cement-based materials

  Xiu-zhi ZHANG

  . 2014, 45(20): 17-0.

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  The effect of the Chemical Structure of CMC on the Stability of Milk Protein

  . 2014, 45(20): 18-0.

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  Abstract：In this paper, two types of carboxymethyl cellulose samples CMCm and CMCe, used for foodstuffs stability, were prepared in mixed isopropanol and ethanol system at high bath ratio and in ethanol system at low bath ratio, respectively. The stability of two types of carboxymethyl cellulose milk micelle was analyzed by their acid salt tolerance property of these milk beverages. The results showed that the CMCm milk beverage showed higher ratio of acidity to viscosity (AVR) , higher temperature resistance, lower precipitation ratio（AVR）and better stability. The morphology structure of milk protein was studied by SEM. It showed that the structure of milk protein with CMCm formed continuous network and homogeneous morphology. However the structure of milk protein with CMCe showed network defects and tendency of aggregation. In order to have in-depth discussion on the structure-property relationship, the distribution of carboxymethyl group on CMCm and CMCe was researched by NMR. The CH2COO- group on anhydroglucose unit (AGU) of CMCm showed regioselectively substituted at C6, while CMCe had high selectively substituted at C2.
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  Immobilization of Laccase on Epoxy-functionalized Macroporous SiO2 Block Materials

  . 2014, 45(20): 19-0.

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  A novel macroporous silica block material was epoxy-modified via post-grafting method under solvothermal conditions. The epoxy-functionalized macroporous silica were employed as the supports for immobilization of the commercial Novozymes laccase by using covalent binding method. Immobilization conditions were optimized, the properties of immobilized and free laccase were studied. The optimum conditions for immobilization of laccase were at the immobilization time of 4h, the buffer of pH 4.5 and the initial laccase concentration of 25mg/ml, under these conditions, the activity of immobilized laccase reaches 101.7U/g. The optimum pH and temperature of immobilized laccase were 4.0 and 50℃, respectively. The experiments show that the immobilization significantly improves the pH stability and thermal stability of laccase. The immobilized laccase can be used repeatedly, and the remained activity is 43.4% after 10 times of reaction with the substrate.
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  Effects of the PVP on Polyarylene sulfide sulfone membrane

  Jia Liu;

  . 2014, 45(20): 20-0.

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  PASS has many advantages such as high temperature resistance and solvent resistance as a kind of membrane material. However, its application is limited because of the poor hydrophilicity. In this study, hydrophilic polymer Polyvinylpyrolidone (PVP) was added to improve thehydrophilicity of PASS membrane. The optical angle gauge, scanning electron microscope, filter bowl and UV spectrophotometer were used to characterize the contact angle, morphology, flux and rejection of membranes with different PVP concentration separately. The experiment results showed that the addition of PVP distinctly improved the hydrophilicity and flux of PASS membrane without a significant change in rejection. In addition, the morphology of membrane was also changed because of the addition of PVP. When the concentration of PVP was 15%, membrane with the best comprehensive performance was prepared.
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  Study on the delayed hypersensitivity of the polyurethanes for vascular grafts

  ;;Xing-Yi XIE

  . 2014, 45(20): 21-0.

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  Dermal sensitization resulting from the raw materials of polyurethanes like diisocyanates has been frequently reported, however the study on allergic reactions to polyurethanes themselves is seldom seen. In this study, the delayed hypersensitivity to three polyurethanes for vascular grafts has been investigated according to guinea pig maximization test (ISO 10993-10). Among the three materials, PCUL2 is a polycarbonate urethane chain-extended with lysine while PCUL2-PO and PCUL2-PN are comb-like polymers from PCUL2 backbones grafted with polyethylene glycol (PEG) diglycidyl ether and PEG bisamine respectively. These materials are highly porous with functional groups intended for conjugating with bioactive molecules to induce in situ endothelialization. The test groups were saline extracts prepared at 70±2℃for 24±2 h using the maximum extraction concentration (0.1 mg/mL). The saline was used as negative control while the 2,4-dinitrochlorobenzene in ethanol (1 g/L) was used as positive control. The results showed that the test groups induced minor hypersensitivity (2/12 for PCUL2-PO; 1/12 for the others). The negative results of the delayed hypersensitivity to the tested polyurethanes suggest that further in vivo studies are worthwhile.
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  Study on Cytocompatibility of Poly (trimethylene carbonate) via Self-polymerization of Dopamine and Covalent Immobilization of Peptide

  ;;;Jin Wang

  . 2014, 45(20): 22-0.

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  Abstract：In this study, due to the poor compatibility of poly (trimethylene carbonate) (PTMC) with endothelial cells (ECs), the polydopamine coating and further immobilization of the peptide REDV (Arg-Glu-Asp-Val) were used to promote adhesion and proliferation of ECs. The hydrophilicity of PTMC film modified by polydopamine coating and immobilization of the peptide REDV was significantly improved; Compared to the surface of PTMC, the surfaces of P-D-48h and P-D-REDV had higher average roughness. The result of QCM-D indicated that 98.4ng/cm2 REDV was immobilized on the PTMC. Endothelial cells in vitro indicated that the PTMC film immobilized with REDV peptides can promote the adhesion, spreading and proliferation of ECs, but this REDV-modified PTMC film had no significant influence on the adhesion and proliferation of smooth muscle cells.
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  Synthesis of polyacrylamide composite microspheres by distillation precipitation polymerization

  Xue-Ming xue ZHANG; ;Qiang CAI ;

  . 2014, 45(20): 23-0.

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  Polyacrylamide composite polymer microspheres were firstly developed by distillation precipitation polymerization using the N-N’ methylene bisacrylamide as the cross-linking agent in acetonitrile solvent. The optimal reaction conditions were obtained by varying the proportion of reactive monomer or crosslinking agent and the total monomer concentration. Some other monomers were also copolymerizated with acrylamide by binary copolymerization or ternary copolymerization, as different monomers have different characteristic, the prepared microspheres have different functions. This method is simple and convenient, the prepared polymer microspheres are mono-dispersed with a narrow size distribution；They swell a few times in aqueous solution and have some elasticity, have a good application in deep water shut-off and profile control for oil reservoir and enhance the oil recovery.
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  The thermal characteristic experiments of PMMA/Cu Carbon nanotubes Composites

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  . 2014, 45(20): 24-0.

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  CNT has the advantages of quasi-one-dimensional hollow and excellent aspect ratio, which makes it a kind of superexcellent thermal conductivity material. In this paper, MWCNTs / poly (methyl methacrylate) (PMMA), MWCNTs / copper (Cu), and MWCNTs / Cu / PMMA composites were prepared by in-situ polymerization and powder metallurgy method respectively. Experimental results show that: the thermal conductivity of the 1.3wt% MWCNTs / PMMA and the 1.3wt% MWCNTs/1.3wt% Cu / PMMA composites increases by 8% and 29.14% compared to the pure PMMA respectively; the 2vol% MWCNTs/Cu enhances the thermal conductivity by 8.47% compared to the pure Cu; SEM figures show MWCNTs are dispersed in the substrates and G band and D band were obtained from the Raman spectrum.
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  Preparation and Mechanical Properties of Soft Magnetic Composite Made of Carbonyl-Iron/Silicone-Rubber

  GAO WeiWANG Kai qiang;Wang Xing Zhe

  . 2014, 45(20): 25-0.

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  In this study, we present the fabrication of thin sheets of magnetic composite materials by organized different volume fraction micron-sized carbonyl iron powder inside RTV-2 silicon rubber in the absence of magnetic field. The tensile mechanical properties of the composites with/without magnetic field were tested utilized the mechanical-magnetic-thermal multi-field instrument and analyzed by some super-elastic models. The results indicated that the mechanical performance of this kind of magneto-active composites is obviously enhanced by applying uniform external magnetic field. The tensile strength and Young’s modulus of the composites significantly increase and its elongation rate at break increases firstly and then reduces with further increase in the volume fraction of particles inclusion. By means of comparison between the experiment data and modeling simulations for the composite in conditions of zero field and an applied magnetic field, it is found that its mechanical behaviors manifest super-elastic characteristic similar to the common super-elastic rubber. The stress-strain relationship can be described satisfactorily by Mooney-Rivlin model with fewer modeling parameters, which may offer convenient approach for mechanical properties and behavior analysis of such soft magnetic composite in engineering applications.
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  Preparation and Performance Study of High Water Stability Zein/CA composite nanofibers Spun by Elecrospinning

  ;;;Da-Wei LI;Lei LUO;;

  . 2014, 45(20): 26-0.

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  Zein/CA nanofibers blend with different mass ratios were fabricated by electrospinning. The spectra of FT-IR indicated that two compositions of composite nanofibers maintained their own original functional groups. The morphologies and diameter distributions of Zein/CA composite nanofibers were observed by SEM. The thermal properties of composite nanofibers were studied by DSC and TGA, the results from characterizations revealed that the composite nanofibers still maintained superior thermal stability with the addition of CA. The wettability and water absorption ability of composite nanofibers were examined by ST, the results elucidated the hydrophilic increased for composite nanofibers with increasing Zein composition. Meanwhile, the composite nanofibers possessed definite water-adsorption capacity.
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  Performance of rut resistance asphalt mixture Compacted in low temperature

  Feng Ma

  . 2014, 45(20): 27-0.

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  There is only about five months for constructing of hot mixture of asphalt in cold regions. Some distresses occur on asphalt pavement which is compacted in very low temperature. In this paper, the performance of a rut -resistance asphalt mixture compacted in low temperature is analyzed. The asphalt mixture with PRLT additive can be molded in 130℃. The high temperature rut test, moisture resistance test and low temperature blending test of asphalt mixture were conducted in laboratory. Test results showed that asphalt mixture with PRLT additive can be compacted in a relatively low temperature. The PRLT additive improves the compactibility of asphalt mixture in cold environment. The construction season is extended for hot asphalt mixture with PRLT additive in cold regions .The PRLT additive improves obviously the high temperature stability of asphalt mixture. At the same time, the low temperature performance, mechanical property and moisture resistance performance are improved to a certain extent.
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  A new artificial mechanical curved surface bi-leaflet cardiac valve: in vitro result

  . 2014, 45(20): 28-0.

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  Abstract：Heart valves which could provide unidirectional function of the blood are autologous valves without nerve control. Under the multi physics factors, the basic movements of the heat valves are directed by blood flow fields and the interaction of valve and tendons. In the clinical study, the patients' survival rate and the incidence of valvular complications all closely depend on the blood flow fields of the heart valve, thus the evaluation of the hemodynamics of the heart valves is critical important. In this paper, thought the theoretical analysis and transient fluid-structure interaction simulation hemodynamic performance of the valve; then tested the self-design curved bileaflet mechanical heart valves under the simulation of dynamic human body environment to measure the hemodynamic of the curved bileaflet heart valve. The utility of pulsating flow experiment makes the evaluation of the performance of artificial mechanical heart valve more effective. The valves' functions, such as valve pressure, opening area and regurgitation volume are all considered and studied under the Vivitest dynamic simulation condition in vitro. Moreover, the clinical hemodynamic of curved bileaflet mechanical aortic valves were proactively investigated, and the dynamic properties were also studied comparing with St.Jude bileaflet valve and GK domestic valve. The results show that the developed new curved heart valve is of excellent hemodynamic.
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  Preparation and properties of polyacrylate superabsorbent with high temperature resistantance

  Xiao-Yun ZHANGXiang-Peng WANG;;;

  . 2014, 45(20): 29-0.

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  A high temperature resistant superabsorbent was prepared through solution polymerization based on sodium acrylate at 25 ℃, using triallylammonium chloride (TAAC) as crosslinker, 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (VA-044) as initiator respectively. The effects on water absorbency at 200 ℃ such as mass ratios of crosslinker to AA, initiator to AA and neutralization degree were studied. Results showed that the swelling ratio of superabsorbent synthesized at the optimum conditions was 824g/g in distilled water and the superabsorbent displayed good salt and pH resistance at high temperature.
工艺 技术
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  Mn-Fe/ACF catalyst for low-temperature selective catalytic reduction of NO

  Yu -Ying ZHENG ;;;;Qian Zhou

  . 2014, 45(20): 30-0.

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  A series of 1.2 %Mn-Fe/ACF catalysts using MX rejects-based activated carbon fibers as supports were prepared by an incipient wetness method and used for low-temperature selective catalytic reduction of NO. The catalysts were characterized by BET, XRD, FESEM and EDX techniques. The results of activity tests showed that addition of an appropriate amount of iron could improve catalytic activity of catalyst, and 1.2 %Mn(0.75)-Fe/ACF catalyst yielded almost 92 % NO conversion at 200 oC at a high space velocity of 56,000 h-1. The results of BET, XRD and FESEM showed that a high surface area and well-dispersed metal oxides on the surface of support would improve the catalytic activity of catalyst.
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  Preparation and NTC characterization of Mn1.56Co0.96Ni0.48O4 nanopowders by solid-state ball milling hydrothermal method

  Ren-Jun MA;Ai-min Chang

  . 2014, 45(20): 31-0.

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  The Mn1.56Co0.96Ni0.48O4 nanopowders were prepared by solid-state ball milling hydrothermal method. The effects of hydrothermal temperature on structure and morphology of the powders were studied and synthesis mechanism of solid-state ball milling hydrothermal method was discussed. The structure and electrical properties of the prepared samples were characterized by X-ray diffraction (XRD), Scanning electron microscope (SEM) and Direct current (DC) resistance temperature measurement. Because it combines the advantages of the solid ball milling method and one-step hydrothermal method, the solid-state ball milling hydrothermal method can be applied to obtain smaller particle size and high dispersion of tetragonal spinel structure nanopowders at low crystallization temperatures. Electrical properties demonstrated that all ceramic samples prepared by the Mn1.56Co0.96Ni0.48O4 nanopowders have obviously negative temperature coefficient characteristics in a wide temperature range from 193K to 373K. The B values were in the range of 3396-3625K.
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  On study of composition and structure of Ti-O film prepared by reactive magnetron sputtering Using CO2

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  . 2014, 45(20): 32-0.

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  In this paper, carbon-doped Ti-O films were prepared on silicon wafer by reaction magnetron sputtering using CO2 as carbon and oxygen source. The composition and structure of as-prepared Ti-O films were characterized by XRD, XPS and Raman spectra. The thickness of the as-prepared Ti-O films was characterized by profilometer. Ultraviolet-visible (UV-Vis) spectrophotometer was used to record the absorbance of as-prepared Ti-O films, the band gaps of as-prepared Ti-O films have been calculated too. The results showed that C doped Ti-O films were synthesized successfully using CO2 gas as C and O source and rutile phase in the Ti-O films had a significant decrease after carbon doped and carbon was doped in the Ti-O lattice by the means of carbon substituted for oxygen, and the crystallization of TiO phase was also promoted. When CO2 and O2 coexisted as reactive gas, Ti atom was priority to combine with oxygen atom and restrained the formation of TiO phase. Carbon doping could decrease the band-gap of and make the absorption edge extended from UV to visible light region and improved the absorption of visible light.