15 December 2014, Volume 45 Issue 23
    

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    研究 开发
  • Study on Constitutive Relation of Asphalt Mixtures Based on Dynamic Creep Test
    Ying-Mei YIN
    . 2014, 45(23): 1-0.
    Abstract ( ) Knowledge map Save
    Under certain temperature and external loads, the strain of asphalt mixtures will occur gradually with increasing of time, this phenomenon is called creep of asphalt mixtures or asphalt pavements. The repeated load creep tests reflected the relationship of the traffic load and deformation response and commonly used to analysis the rutting resistance performance of asphalt pavements at high temperature. In order to simulate the mechanical condition of asphalt pavements and describe the dynamic creep properties of asphalt mixtures, the dynamic creep tests of four asphalts and two asphalt mixturesdynamic creep test were carried out in this paper. During the dynamic creep tests, it is found that dynamic creep of asphalt mixtures was nonlinear; meanwhile the dynamic creep test data are fitted using classic Burgers model and fractional derivative Burgers with the series combination of the Maxwell model and fractional derivative Kevin model, and comparative analysis of the fitting results. It is showed that the fractional parameter a represents the memory role of the materials, fractional derivative Burgers model can describe quantitatively the nonlinear of dynamic creep property and analyze high-temperature property for asphalt mixtures.
  • Synthesis and characterization of Core-shell magnetic molecularly imprinted polymers for solid-phase extraction of Rhodamine 6G
    Xiao-Yan LI
    . 2014, 45(23): 2-0.
    Abstract ( ) Knowledge map Save
    Fe3O4 magnetic nanoparticles were synthesized by the chemical co-precipitation method. With (3-aminopropyl)triethoxysilane (APTES) on the surface modification, Fe3O4 @ SiO2-NH2 nanoparticles were formed. Core-shell magnetic molecularly imprinted polymers (Fe3O4@MIPs) were prepared by using Rhodamine 6G as template molecule, acrylamide (AM) as functional monomer, trimethylolpropane trimethacrylate (TRIM) as cross-linking agent, and amino-modified Fe3O4 magnetic nanoparticles as the magnetic core. The Fe3O4@MIPs were characterized using a Fourier transform infrared spectrometer(FT-IR), field emission scanning electron microscope (FESEM), vibrating sample magnetometer(VSM), and thermogravimetric analysis (TGA). The Fe3O4@MIPs showed a highly improved imprinting capacity and significant selective; they could be used as solid-phase extraction material and applied to the safety detection of illegal add Rhodamine 6G in foods.
  • Surface Tension and Surface Absorption of Undenatured Collagen Bio-surfactant
    ;;;;
    . 2014, 45(23): 3-0.
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    The surface tension and the surface absorption properties of undenatured collagen bio-surfactant (CBS) in aqueous solution were investigated in this paper. The results showed that with CBS concentration increased, the surface tension of CBS solution decreased firstly and then kept at constant; the equilibrium surface tension was 55.92 mN/m. Meanwhile, when the pH value of CBS solution was close to the isoelectric point of CBS, the net charge of CBS would decrease, which resulted in the lower surface tension. At lower temperature, CBS exhibited good surface activity; while at higher temperature (>35 °C), the surface tension increased rapidly due to the denaturation. The absorption of CBS solution belonged to Langmiur-type absorption and the saturated absorption quantity were close according to the γ-lgC, Γ-C and C/Γ-C fitting curves, which were 1.86×10^-10, 1.97×10^-10 and 2.03×10^-10 mol/cm^2, respectively. Additionally, the absorption free energy of CBS was -3.53 kJ/mol, suggesting that the surface absorption of CBS in aqueous solution could be spontaneous at the standard condition.
  • Adsorption Mechanism of Amphoteric Bacterial Cellulose for Persistent Pollutants
    ;;
    . 2014, 45(23): 4-0.
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    Allylamine-acrylic acid-bacterial cellulose (al-AA-BC) as amphoteric adsorbent was preparation with bacterial cellulose as new material, allylamine and acrylic acid as monomer ceric, ammonium nitrate as initiator. The adsorption isotherm and kinetic characteristics of amphoteric bacterial cellulose for Cu2+、Pb2+、Cd2+ and Cr(VI) were studied. And the adsorption mechanism was investigated by the static adsorption experiments. The results show that adsorption process can be described by Langmuir-Freundlich model, as shows the adsorbent must has some heterogeneity after graft copolymerization of BC. And the adsorption rate of al-AA-BC to heavy metal ions could be well fitted by pseudo-second rate model, as illustrates adsorbents adsorbed metal ions mainly via chemical adsorption. The orders of adsorption ratio of adsorbent to the for different persistent pollutants is Cd2+＞Cr(VI)＞Pb2+＞Cu2+. Because the constants C obtained with a particles internal diffusion model is not zero，particles internal diffusion is not the only one controlling rate step.
  • Surface modi?cation of chitosan by electrostatic adsorption with polyanion bearing phosphorylcholine groups
    . 2014, 45(23): 5-0.
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    Three random copolymers poly(2-methacryloyloxyethyl phosphorylcholine-co-methacrylic acid) (PMAs) were synthesized by free radical polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and methacrylic acid (MA) with different monomer ratios under monomer-starved conditions. The synthesized PMA polyanions were assembled on chitosan (CS) ?lm surfaces via electrostatic adsorption (CS-PMA). The modi?ed surfaces were characterized by dynamic contact angle (DCA), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The anticoagulation property of the surfaces was estimated by platelet adhesion measurements. The results indicated that cell outer membrane mimetic structures were formed on the modi?ed surfaces with PMA and the anticoagulation property of the modi?ed surfaces was signi?cantly improved. This facile method of fabricating cell outer membrane mimetic surfaces may have potential applications in the ?elds of hemocompatible coatings, drug delivery, and tissue engineering.
  • In Situ AFM Observations on the Defects of ZTS Crystals
    ;;
    . 2014, 45(23): 6-0.
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    The real-time growth process of the (100) face of zinc tris-thiourea (ZTS) was observed using in situ atomic force microscopy (AFM). It comes out that pits could be result from the hollow surface and impurities on crystal surface that block up step advancement. The coverage by the macrostep of pits and impurities is the basic cause for inclusion generation. The impurity pinning phenomenon of ZTS crystal was observed for first time. Immobile impurities didn’t terminate the advancement of steps.
  • Microstructure changes of reduced activation steel after deuterium ion irradiation at high temperature
    Ping-Ping LIU; ;
    . 2014, 45(23): 7-0.
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    A good understanding on the effect of deuterium which exists in the environment of fusion reactions and irradiation is important to develop structural materials in fusion reactors and for a safe design and operation of innovative nuclear systems. Reduced activation ferritic/matensitic (RAFM) steel is considered as the candidate of structural materials for fusion power reactors due to their excellent resistance to swelling under irradiation and low cost. To investigate the effects of deuterium ion and irradiation on the microstructure of RAFM steel, CLAM steel, one kind of RAFM steel, and Fe-10Cr model alloy have been irradiated by 58 KeV deuterium ion at 500 °C The microstructural changes were investigated by high-resolution transmission electron microscope (HRTEM). The results show that lots of defects such as dislocation loops have been induced. Precipitates have also been induced after deuterium ion irradiation at high temperature. According to the HRTEM image of M23C6 in irradiated CLAM steel, no obvious amorphization has been observed. This complex phenomenon was discussed.
  • Preparation and properties of polyethylene terephthalate/mutil-walled carbon nanotubes nanocomposites
    ;Chang-kun DING ;;
    . 2014, 45(23): 8-0.
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    Polyethylene terephthalate (PET)/carbon nanotubes (CNT) nanocomposites were fabricated via a simple melt compounding method using an Mini-Lab twin-screw extruder. The effects of the raw and acid-modified multi-walled carbon nanotubes (MWNT-COOH) on the conductive properties and crystallization behavior of PET nanocomposites were comparatively investigated via surface resistance meter, field emission scanning electron microscope (FESEM) and differential scanning calorimeter (DSC). It was revealed that the nanocomposites had antistatic and conductive functionality when the loading of CNT was more than 1wt%, which formed three-dimensional conductive networks. MWNT-COOH owing polar oxygen-containing groups on the surface was beneficial to combine with PET matrix and the uniform dispersion. So conductive performance of PET/MWNT-COOH composites were better than that of PET/MWNT composites. Moreover, the crystallization temperatures of the nanocomposites were increased more than 40℃ compared with neat PET. Very obvious heterogeneous nucleation and induced crystallization effects could be achieved when the loading of CNT was only 0.1wt%. Meanwhile, the crystallinity of the nanocomposites were improved and the melting points were increased slightly.
  • Study on heat transfer performance of POM/Aluminum alloy Interpenetrating Phase Composites
    Zhen ZHANG;Chun-Guang LONGFang-Yu GUO;Yang SU;Yan YIN;Tai-Shan CAO
    . 2014, 45(23): 9-0.
    Abstract ( ) Knowledge map Save
    Polyoxymethylene(POM)/Aluminum alloy foam Interpenetrating Phase Composites were prepared by injection molding technique after aluminum foam was modified by silane coupling agent KH570. FT-IR spectrophotometer, scanning election microscope(SEM) and thermal conductivity meter were employed to research the infrared structure of the modified aluminum alloy foam , the interfacial bonding and the heat transfer performance of the POM/aluminum alloy foam interpenetrating phase composites The results showed that silane coupling agent KH570 was grafted to the aluminum alloy surface, The interface between aluminum alloy and POM were bonding well, the heat transfer performance of composites improved with the filling with aluminum alloy foam. When the porosity of aluminum alloy foam were ranged from 60.48% to 75.41%, the thermal conductivity of the POM/aluminum alloy foam interpenetrating phase composites decreased with the increasing the porosity of Al alloy foam percentage. Then the thermal conductivity of samples was between 10.2945W/(m·K) to 17.6471W/(m·K).
  • Mechanism of high temperature performance of natural asphalt based on gel permeation chromatography
    Feng Ma;
    . 2014, 45(23): 10-0.
    Abstract ( ) Knowledge map Save
    In order to understand the relation between molecular weight distributions and road performance of asphalt modified with natural asphalt, the gel chromatography tests are conducted. The weight-average molecular weight, number-average molecular weight, peak molecular weight and distribution ratio are analyzed. The properties of asphalt modified with natural asphalt are evaluated by penetration test, softening point test, viscosity test and aging test. Test results show that molecular weight decrease in M<1000 range, and that molecular weight increase in 1000 -6000 range. There is a good linear relation between the weight-average molecular and road performance. There is a good linear relation between the percentage content of M<4000 and road performance. The additive of natural asphalt increases the high temperature performance of base asphalt and aging asphalt.
  • Preparation of Co3O4/mpg-C3N4 catalyst and its visible-light photocatalytic performance
    ;;;
    . 2014, 45(23): 11-0.
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    Cobalt modified mesoporous graphitic carbon nitride (Co3O4/mpg-C3N4) was synthesized via a facile impregnation method. The as-synthesized catalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption analysis, UV-vis absorption spectra (UV-vis DRS) and Photocurrent transient measurement, respectively. It indicated that the addition of Co3O4 could improve the light-absorbing ability of mpg-C3N4 and enhance the separation efficiency of electron and hole on the catalyst surface. The Co3O4/mpg-C3N4 photocatalyst showed prominently enhanced photocatalytic activity for the degradation of methylene blue (MB) under visible-light irradiation than that of mpg-C3N4 and an optimum content of cobalt doping in the mpg-C3N4 was 3%.
  • Effect of size of nano-silica on the mechanical properties of the nano-silica/Natural Rubber composites
    . 2014, 45(23): 12-0.
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    Nano-silica with different size was used to prepare the nano-silica/nature rubber composites. The influence of the structure of nano-silica (15nm, 30nm and 80nm) with the different sizes on the basic properties of nano-silica/natural rubber(NR) composites such as mechanical properties, Mullins effect of the static properties, Payne-effect of the dynamic properties, DMA, the dynamic heat generation and tanδ, were investigated in this work. The results show that when size of nano-silica increases in the nano-composite, tensile strength of the composite material becomes large and Mullins effect exhibited a upward trend. The particle size becomes larger, the Payne-effects and the tanδ of the composite are decreased obviously, meanwhile, the dynamic compression temperature rise lower. Payne-effect and Scanning electron microscope (SEM) show that the large size nano-silica is easy to disperse in rubber, while the small size nano-silica of the composites has a good aggregation. Dispersion of nanoparticles has a direct effect on the mechanical properties in nano-composite.
    • 综述 进展
  • Advances in the Application of Heavy Metals and Antibiotics Adsorption on Graphene
    ; Jie MA
    . 2014, 45(23): 13-0.
    Abstract ( ) Knowledge map Save
    Heavy metals and antibiotics pollutants share the characteristics of high stability, resistance to degradation, high toxicity, and accumulative effects. With increasing probability of synergistically toxicity effect in water and soil environment, they have a tendency to become a global problem. Graphene, one of the most popular carbon nanomaterials, has large specific surface area and high activity characteristics. As an excellent adsorbent, it has broad prospects in application in the field of environmental pollution control. Graphene oxide is the oxide form of graphene with large number of oxygen groups on its surface, it could be easily modified chemically and is more hydrophilic than graphene, it has excellent qualities as adsorbent for the removal of pollutants from aqueous solution. However, as nano powder adsorbents, graphene oxide and graphene is easy to agglomerate and difficult to be separated from water, which restrict its practical application and speed the emergence of three dimensional macro graphene aerogels. Graphene aerogels effectively solve the problem of agglomeration and separation and show better characteristics and application prospects. 3D graphene has various appearances and microstructures owing to different preparation methods such as chemical vapor deposition, hydrothermal method and chemical oxidation and reduction method, its shape could be exist as either bulk, plate or nets. The generation of 3D graphene constructs the bridge of graphene from micro investigation to macro investigation. In recent years, the investigations on pollutants adsorption on graphene are wide and deep, not only the improvements of preparation methods to get better characteristics, but also broaden the kinds of pollutants as adsorbate. In this paper, adsorption of heavy metals and antibiotics on graphene, graphene oxide and graphene aerogel including the modification of graphene to become better adsorbents in recent years are reviewed, moreover, the research trend and hotspots are explored and the trend of future research is outlined.
    • 工艺 技术
  • Experimental Investigation on Magnetic-control Mechanical Behavior of Magnetorheological Elasticity Cement
    . 2014, 45(23): 14-0.
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    Elasticity cement consisting of high viscosity linear polysiloxane based magnetorheological elasticity cement (MEC) with 20%, 40% and 60% weight fraction of carbonyl iron powder were prepared. Magnetorheological rheological properties and dynamic mechanical properties were systematically tested. The constitutive relation and parameters of MEC were identified. The relationship of viscoelastic properties with magnetic field, iron powder content, shear strain and shear frequency were analyzed. The results demonstrate that the constitutive relation of MEC can be described using a Herschel-Bulkley model. The shear stress and stiffness of MEC with 60% weight fraction of carbonyl iron powder can be controlled by magnetic field with a wide range (for example, adjustable range of shear stress is from 16 kPa to 128 kPa, adjustable range of storage modulus is from 0.52 MPa to 3.28 MPa). The shear stress increases, the elasticity increases and the viscosity decreases with the iron mass fraction and magnetic field increasing. The critical strain, which is from the linear viscoelastic region to nonlinear viscoelastic area, is different at various magnetic field. The range of the linear viscoelastic region can be broaden with the magnetic field increasing. Magnetorheological elasticity cement is independent of frequency (0 ~ 80 Hz) in the linear viscoelastic range.
  • A Study of Metallization for PZT Piezoelectric Buzzer Using Magnetron Sputtering Technology
    Mei HE;De-Miao WANG
    . 2014, 45(23): 15-0.
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    We proposed a novel metallization process for PZT piezoelectric buzzers using direct-current (DC) magnetron sputtering method, and compared it to the traditional screen-printed method Three groups of samples with different sputtering processes were investigated, namely Cr/Cu/Ag, Ti/Cu/Ag and Cu/Ag multilayer structures. The micro-structure of surface and cross-section view of metallized films were analyzed by scanning electron microscopy (SEM), other aspects, such as adhesion and electric characteristics were also investigated. Results show that the performance of films prepared by magnetron sputtering method has surpassed those by screen-printed method in all aspects. The proposed method provides more dense, uniform, and conformal films than the traditional one, and the Ti/Cu/Ag structure shows the best performance owing to the matching of materials between Ti glue layer and PZT substrate. The largest tensile strength reaches 13.5 MPa, and the mean resonant resistance and electromechanical coupling coefficient are 25 Ω and 0.7, respectively, which are better than those of screen-printed ones. Additionally, the thickness of metallized film of magnetron sputtering is only about 1.7 micron that is much less than the screen-printed one. Due to the good performance, low-cost as well as non-pollution, the magnetron sputtering show promising applications in piezoelectric buzzer and other PZT based devices.
  • Preparation of low-dimensional photonic crystals and its application in organic lasing cavity
    Yue-Ling Jing
    . 2014, 45(23): 16-0.
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    A simple and low-cost fabrication method of controllable one-dimensional and two-dimensional photonic crystal arrays was reported in this paper by the means of e-beam lithography with reactive Ion etching. We employed efficient etching process which could improve accuracy control in the sizes, period, and surface morphology of photonic crystal arrays. Based on these advantages, the high-performance distributed feedback polymer lasing cavity has been fabricated. The optical pumping results show that we have successfully achieved a lasing from organic laser dye with a low amplified spontaneous emission threshold of 260 kW/cm2 and a narrow full width half maximum of 0.22 nm.
  • Preparation and dielectric properties of ZnO-MgO-TiO2-SnO2 system high frequency dielectric ceramic
    Xue-Li FENG; ;;
    . 2014, 45(23): 17-0.
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    (1-x)ZnO-xMgO-0.88TiO2-0.12SnO2 ceramic was synthesized as a type of new ceramic by doping MgO on the basis of ZnO-TiO2-SnO2 ceramic, of which the phase transition, microstructure and high frequency dielectric properties were studied. The results showed that without any sintering aids, the compound with pure spinel structure (Zn0.5,Mg0.5)2(Ti0.88,Sn0.12)O4 can be sintered at 1080℃ while x=0.05. According to the bulk density and dielectric properties, the compound’s relative density is 94.4% with excellent high-frequency dielectric properties of ε=18.88，tanδ＝5×10-4,τ?=2.89ppm/℃ at 1MHz, indicating that the compound can serve as a promising low-sintered high-frequency dielectric capacitor.
  • Fabrication and characterization of freestanding β-SiC/SiOxCy/Cfree heat dissipation ceramic films by precursor method
    Rong-Qian YAO;Chang-Ping FU;Shuai-Feng ZHANG;;Zu-De FENG
    . 2014, 45(23): 18-0.
    Abstract ( ) Knowledge map Save
    Freestanding β-SiC/SiOxCy/Cfree nanocomposite films were synthesized by melt spinning the polycarbosilane (PCS) precursor. Their microstructure were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and Raman spectroscopy, morphology analysis was investigated by scanning electron microscope (SEM). Resistivity and thermal conductivity of the films were measured at room temperature. Effect of pyrolysis temperatures on the heat dissipation properties of nanocomposite films were investigated. The results show that thermal conductivity increases as the resistivity of the β-SiC/SiOxCy/Cfree films decreases by increasing pyrolysis temperatures. The sample sintered at 1200 °C with good insulation (2.1×108 Ω.m) and high heat transfer capability (46.8 W/m.K) can be silk-screened and used as heat dissipation substrate for high-power LED devices. The obtained results are expected to have important applications in high-temperature electronic and advanced optoelectronic devices.
  • Preparation and Thermal Properties of Paraffin/ SiO2 Phase Change Material
    . 2014, 45(23): 19-0.
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    Phase change material based on paraffin acting as the heat-absorbing material and nano SiO2 as the supportive material was prepared by sol-gel method, under the condition of using silane coupling agen. The morphology, chemical characteristics and thermal properties of paraffin/ SiO2compostie PCM were investigated by transmission electron microscopy, Fourier-transform infrared, thermo-gravimetric analysis, and different scanning calorimetry. Meanwhile, thermal conductivity coefficient of the paraffin/ SiO2compostie PCM was measured. The results indicated that the paraffin be immobilized in three-dimensional network structure during the process of phase change. The proportion of paraffin in the composite is 39% by mass, and the phase change temperature and latent heat were 39.15℃and 59.33J/g, respectively. The thermal conductivity coefficient of the paraffin/ SiO2compostie PCM was 0.0845W?m-1?K-1.through the transient hot-wire method. Hence, the paraffin/ SiO2compostie PCM can be applied as the thermal insulation material.
    • 研究 开发
  • Cushioning properties of two-layered cushioning structure made from honeycomb and calcium plastic board subjected to quasi-static compressive loading
    JUN FENG
    . 2014, 45(23): 20-0.
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    Basing on universal testing machine，the static stress-strain curve of calcium plastic corrugated paperboard, honeycomb paperboard and composite structure were obtained. By calculating the relationship curves between the stress and energy absorption, the curves of three different type cushioning structure, namely, composite cushioning structure made from honeycomb and calcium plastic board, single-layered honeycomb and calcium plastic board were compared and analyzed subjected to different static compression loading. The empirical formula of the composite structure of the maximum stress-speed was established and corresponding parameters in the model were identified by the least squares method. The experimental results investigate that the theoretical model can provide guidance for cushioning packaging design.
    • 综述 进展
  • The research progress of friction and wear properties of polyetheretherketone and its modified materials for artificial joints
    ;;;;
    . 2014, 45(23): 21-0.
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    Polyetheretherketone（PEEK）provides new hope for the development of the long lifetime artificial joints due to its excellent friction and wear properties. The application and research progress for the friction and wear properties of PEEK, carbon fiber reinforced PEEK, particle-filled PEEK, plasma modified PEEK applied as artificial joint material surface using conventional tribology method and on articular surface such as total hip, knee and artificial intervertebral disc prosthesis using simulators were summarized respectively. At last, the development trends were prospected.
    • 研究 开发
  • Research on intergranular corrosion of welded joint of nuclear-grade austenitic stainless steel
    Rui Luo;Xiao-nong CHENG ;
    . 2014, 45(23): 22-0.
    Abstract ( ) Knowledge map Save
    Abstract: The tendency to intergranular corrosion of the welded joints of Incology800H and Cr18Ni30Mo2Al3Nb alloy was investigated. Sensitizing treatment of 650 ℃×100 h and no treatment was used. The microstructure, morphology and the intergranular corrosion resistance of samples were studied by optical microscope、SEM and Method of copper sulfate-sulfuric acid test for stainless steels. The results show that the dissimilar welded joints are all the single austenite (γ) organizations. TiN inclusions lead to pitting corrosion in alloy 800H. However, no excessive pitting corrosion in Cr18Ni30Mo2Al3Nb alloy. As can be seen from the weightlessness, corrosion depth test results, clearly shown that Cr18Ni30Mo2Al3Nb welded joint has better intergranular corrosion resistance than 800H.
  • Study on preparation dry sample of polyacrylonitrile nascent fibers
    . 2014, 45(23): 23-0.
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    Polyacrylonitrile (PAN)-spun fibers are obtained by dry jet wet spinning process, different drying methods are used to obtain PAN nascent fibers dried samples. Then studied the effect on physical characteristics, surface morphology and internal structure of three methods by contrasting natural drying, air forced drying and freeze-drying. Three methods all caused shrinkage on the nascent fiber samples, cross-sectional area and length of samples were reduced, but with different degree of change. And three drying methods have different effects on the morphology of the surface of the nascent fiber PAN, crystallization characteristics, the amount of residual dimethylsulfoxide (DMSO), and pore structure. The results show that the impact of freeze drying on PAN nascent fibers are minimum, and it can effectively preserve the original structure of PAN nascent fibers spun fibers, so it can be used for sample preparation for testing.
    • 工艺 技术
  • Effect of KH550-modified Al2O3 on the properties of PI/Al2O3 composite films
    ;Ling Weng
    . 2014, 45(23): 24-0.
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    In this paper, the surface of Al2O3 was modified with the different content of γ-aminopropyltriethoxyl silane, the modified Al2O3 particles was characterized by spectroscopy(FT-IR) and X-ray diffraction(XRD). The result shows that KH550 was attached on the surface of Al2O3 particles successfully. And the Al2O3 particles and KH550-modified Al2O3 particles were added to the PI matrix, respectively, PI composite films with 16wt% of Al2O3 content were prepared with in-situ polymerization. The cross-section microstructure of the obtained composite films was characterized with scanning electron microscope(SEM), and the result indicates that different contents of KH550 have a great influence on the dispersion of inorganic particles. In addition, the mechanical properties and breakdown field strength of the composite films were tested. Test results show that when the content of KH550 is 2wt%, the tensile strength and elongation at break of PI/KH550-Al2O3 composite films were optimal and is 130.25MPa, 11.79% respectively. Compared with the PI/Al2O3 films, the tensile strength and elongation at break of PI/KH550-Al2O3 composite films was increased by 22.8% and 44.49%, respectively, and the breakdown field strength of that is similar to PI/Al2O3 films.
  • Synthesis of Cu-water thermal conduction nanofluids using sodium citrate as dispersant by one step method
    Fei-Long ZHANG
    . 2014, 45(23): 25-0.
    Abstract ( ) Knowledge map Save
    Cu-water thermal conduction nanofluids were synthetised by one step method using sodium citrate as dispersant , KBH4 as the reducing agent, CuS04?5H20 as the oxidant. The technological parameter: n(CuS04?5H20)：n(KBH4)=2.5:1, the content of sodium citrate is about 0.7mol/L, the reaction temperature is 40℃, the reaction time is 100min. TEM proved that Cu nano-particles were uniformly dispersed in thermal conduction nanofluids; laser granularity apparatus showed that particle average size is 1.1nm; Thermal conductivity is 0.7812W/m.K at 25℃, and 30% higher than pure water.
  • Influence of seed crystals and crystallization mode on the synthesis of metal-organic framework MIL-101
    Heng Chen;;;
    . 2014, 45(23): 26-0.
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    In order to enhance the yield of metal-organic framework MIL-101, seed crystals method and dynamic hydrothermal crystallization method were involved to synthesize MIL-101.The static hydrothermal crystallization method was also involved to compare with the dynamic hydrothermal crystallization method. The influence of seed crystals and crystallization mode on the yield and grain size of MIL-101 was investigated by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and N2 physical adsorption. The result showed that MIL-101 powders as seed crystals were dissolved into appropriate structural unit as a growth core of MIL-101 crystal during the synthesis of MIL-101. Consequently, the crystallization introduction period was shortened and the yield of MIL-101 was enhanced. Crystallization mode affected the yield and grain size of MIL-101. The yield of MIL-101 synthesized by dynamic crystallization method was higher than static crystallization method, which were increased with the increasing of stirring speed when it is lower than 200 r/min. The grain size of MIL-101synthesized by dynamic crystallization method was less than static crystallization, which was decreased with the increasing of stirring speed.
  • Synthesis of nanostructured CrSi2 films doped with Ti
    Song Gui Hong
    . 2014, 45(23): 27-0.
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    In this paper, the CrSi2 films doping Ti are synthesized by depositing alternatively Cr,Ti layer and Si layer using multi-target magnetron sputtering system and following annealing in vacuum. The film contains part deposited Si phase and a few CrSi phase as well as the (Cr,Ti)Si2 phase after the film deposited alternatively is annealed for 2h at 500℃. The deposited Si phase and CrSi phase reduce but (Cr,Ti)Si2 phase increase with extending annealing time. The mean grain size computation by half height wide of X-ray diffraction peak shows that the grain size of (Cr,Ti)Si2 phase in films approximately linearly increases from 68 nm to 81 nm as the annealing time increases from 2h to 8h. The films obtained by annealing are nanostructured and single (111) orientation. The diffraction angle of (Cr,Ti)Si2 phase (111) plane gradually move to small value with increasing Ti mol. fraction, which suggests the crystalline constant a and c of (Cr,Ti)Si2 phase gradually increase. The variation of crystalline constant shows approximately linear relation with Ti mol fraction. It is the result that the Cr atom in lattice is substituted by the longer radius Ti atom. The computation and analysis show that the (Cr,Ti)Si2(111) epitaxial growth on Si(100) results from the low lattice distortion energy at interface. The prefer orientation degree of CrSi2(111) decreases with increasing Ti mol. fraction.
  • The preparation and dielectrical properties of Fe-Si-B/resin composite
    Qing HOU; ;;;;;
    . 2014, 45(23): 28-0.
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    In this paper, resin was used as matrix to prepare epoxy resin matrix composite and phenolic resin matrix composite, in which the content of amorphous Fe-Si-B powder vary 20 wt% to 80 wt%. The phase characterization, microstructure and dielectric properties of the composite were analyzed by XRD, SEM and impedance analyzer. The result suggested that both the dielectric constant and conductivity of the samples raised with the increase of the conductive phase, moreover, the conductivity showed a exponential relationship with frequency. The reactance decreased with the increase of frequency, and took a negative value over the testing frequency range which indicated a capacitive character.
  • Design and Preparation of Multi-Functional Single-Layer Silica Antireflective Coatings
    Xin-Xiang ZHANG ;;;
    . 2014, 45(23): 29-0.
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    Single-layer antireflective (AR) coatings with high transmittance have been designed by the thin film design software (TFCalcTM). The silica sols were prepared by using tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as co-precursors, HCl as catalyst, and cetyltrimethylammonium bromide (CTAB) as template. The single-layer AR coatings with multi-functions were prepared by the dip-coating process combined with evaporation-induced self-assembly. It was found that the transmittance of AR coatings at 650 nm was 99.9%, and the photovoltaic transmittance (TPV) at 400-1100 nm reached to 98.7%. The introduction of methyl groups increased the water contact angle of AR coatings from 24 to 85. In addition, this AR coating also had good abrasion-resistance. This multi-functional silica AR coating with high transmittance, good abrasion-resistance and improved hydrophibicty will find important application in the field of solar cells.
  • Study of Hydroxyapatite Materials Doped with Europium and Its Luminescence Property
    ZHAO Gao-Yang;;;
    . 2014, 45(23): 30-0.
    Abstract ( ) Knowledge map Save
    A series of hydroxyapatite (HAP) particles doped with different content of europium (Eu3+) were designed and synthesized by a ‘‘one-pot’’ wet-chemical precipitation method and their structure, composition and luminescent property were characterized. XRD patterns and IR adsorption peaks showed the characteristic structure and corresponding groups for Eu doped HAP samples. The typical emission peaks attributed to Eu ions were observed in emission spectra of HAP:xEu samples under excitation. The luminescent intensity of Eu doped samples enhanced with the rising Eu ions content. Meanwhile, the fluorescent lifetime of doped samples decreased with the rising doped concentrations. Furthermore, the ratio of intensity between 617 nm and 595 nm corresponding to electric-dipole and magnetic-dipole (IR/IO) was also observed to increase with Eu ions content, which revealed the proportion of substitute type and site of Ca ions by Eu ions and was helpful to realize the substitute process and functional structure design.
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