15 January 2015, Volume 46 Issue 01
    

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    工艺 技术
  • Study on Synthesis and Electromagnetic Properties of ZnFe2O4 Nanoparticles Prepared by Co-precipitation Method
    . 2015, 46(01): 1-0.
    Abstract ( ) Knowledge map Save
    ZnFe2O4 spinel nanoparticles were synthesized by co-precipitation method. By means of Transmission electron microscopy (TEM), X-ray diffraction (XRD), Vibrating sample magnetometer (VSM) and Vector network analyzer, we analyze the surface morphology, crystal structure and chemical composition of the samples, and study its magnetic properties and electromagnetic properties. The research results show that the particles size was in the range of 14-17nm, uniform grain distribution and single-crystal cubic structure as the calcination temperature of the precursor mixture was 500℃. When the calcination temperature was from 500 to 800℃, magnetic moment was antiparallel alignment, performance for the ferromagnetic material. With the increase of calcination temperature, the crystallization of samples increased, but the saturation magnetization decreased. The selected sample has repeatedly appeared to the loss peaks in the range of 2-18GHz, in the process of relaxation polarization and dispersion of the medium, the electric energy is converted into heat energy and dissipated. This preparation method has many advantages, such as, the simple process, low equipment cost, excellent electromagnetic properties etc.
  • Preparation of multilayer coated glass with Low-E and thermal insulation properties
    Zhao Gaoling
    . 2015, 46(01): 2-0.
    Abstract ( ) Knowledge map Save
    SnO2:F/silica aerogel multilayer coated glass was prepared via sol-gel process. SEM, thermal conductivity meter，FT-IR，and UV-Vis optical spectrometer were used to characterize the mophology, thermal conductivity, low-E performance and transmittance of the coated glass. The results showed that the transmittance of the coated glass was up to 75%, the emittance was 0.53. Compared to FTO glass, the thermal conductivity of multilayer coated glass decreased from 3.615W/m to 3.368W/mK, indicating that the multilayer coated glass possessed both low thermal conductivity and low emittance properties.
  • Influences of post-treatment processes on the bioactivity of anodized titanium
    Xiuchun Yang
    . 2015, 46(01): 3-0.
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    Abstract: Titanium and titanium alloy have become good bone repair and replacement materials because of their good mechanical and biological properties. In order to improve the bioactivity of pure titanium metal, two-step electrochemical anodic oxidation was adopted to modify the surface of titanium metal, which favors the formation of porous nanostructures on Ti surface. After heat treatment at 450℃, the anodized Ti sample was further treated by NaOH solution or NaOH-CaCl2 solution. Finally, the post-treated sample was immersed into a simulated body fluid (SBF) to study the growth process and mechanism of apatite on the sample surface. The phase, morphology, elementary composition of the samples were characterized via X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) with the energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectrometry (FTIR), and inductively coupled plasma atomic emission spectrometry (ICP-OES). The results revealed that amorphous TiO2 nanotube arrays can not induce the formation of apatite on its surface. While the well-crystallized anatase nanotube arrays formed after annealing at 450℃ has some certain degree of bioactivity, namely, it can induce the formation of some apatite on its surface. Further post-treatment by NaOH-CaCl2 solution can accelerate the formation of hydroxyapatite. Its thicknesses are about 5μm after the post-treated samples are immersed in the simulated body fluid (SBF) for 8 days. The hydroxyapatite layer is composed of many flower-like spheres with nano-flakes.
    • 综述 进展
  • The Preparation and Application of Phenolic Resin-based Porous Carbon
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    . 2015, 46(01): 4-0.
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    As a common precursor of activated carbon, phenolic resin has attracted much attention of researchers due to its unique properties. The pore structure plays an important role in the performance of activated carbon. Therefore, pore size tailoring is crucial in the preparation process. There are lots of pore size tailoring methods of activated carbon, such as metal catalytic method, adding pore-forming agents and template technique. The obtained phenolic resin-based porous carbon with different pore size distribution has extensive applications in fields of environmental protection, electrochemistry, medicine and catalysis. This paper reviews the preparation of phenolic resin-based porous carbon and different pore size tailoring methods as well as its main applications in recent years. The future research and application of phenolic resin-based porous carbon are also highlighted in this review.pore-forming agents and template technique. The obtained phenolic resin-based activated carbon with different pore size distribution has extensive applications in fields of environmental protection, electrochemistry, medicine and catalysis. This paper reviews the preparation of phenolic resin-based activated carbon and different pore size tailoring methods as well as its main applications in recent years. The future research and application of phenolic resin-based activated carbon are also highlighted in this review.
  • Particulate Reinforced Metal Matrix Composites Prepared by Spray Forming: an Overview
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    . 2015, 46(01): 5-0.
    Abstract ( ) Knowledge map Save
    Spray forming is a new developed high-performance metal forming technology, during the process of which the metal stream is firstly atomized into a spray of droplets by high-pressure gas jets and then deposited on a substrate. After the introduction of spray forming into the preparation of metal matrix composites field, several preparation methods are developed such as particulate premixed spray forming, reaction spray forming and spray deposition. The principles, characteristics, and development situations of the mentioned methods are reviewed. Through the comparative analysis, spray deposition is a more promising preparation method because of the technological feasibility and extensive adaptability. At last a self-developed spray deposition technology is introduced. During the progress, a gas-particulate dual-phase is used as the atomizing medium to improve the atomization efficiency and enhance the particulate distribution uniformity.
  • Research Progress of LiNi1-x-y CoxAlyO2 as Cathode Materials for Lithium Ion Battery
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    . 2015, 46(01): 6-0.
    Abstract ( ) Knowledge map Save
    The mixed Ni, Co, Al material has the highest capacity as the industrialized cathode of lithium-ion batteries, which has the advantages of reasonable cycle ability, low cost and rich raw materials. It is the candidate of the potential materials for lithium ion power battery. However, it is difficult to prepare a pure phase of LiNi1-x-yCoxAyO2 by these methods. On the other hand，the disadvantages，such as low Charge-discharge efficiency，poor stability in high temperature and low tap density，constrained its development and application. Current research of LiNi1-x-yCoxA1yO2 material was focused on this review, including synthetic methods, doping, coating and surface treatment. The application and prospects of LiNi1-x-yCoxA1yO2 for lithium ion batteries are predicted.
    • 研究 开发
  • Nanoindentation characterization of strain rate sensitivity of lead-free solders
    ;;Guo-Zheng Yuan;;
    . 2015, 46(01): 7-0.
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    ABSTRCT： Nanoindentation tests were conducted on lead-free solders of Sn-3.0Ag-0.5Cu、Sn-0.7Cu and Sn-3.5Ag to investigate the strain rate sensitivity at room temperature. For the lead-free solders, indentation load under the same indentation depth increases with increasing loading strain rate. The contact stiffness during loading increases with indentation depth approximatively linearly, and the elastic modulus of the lead-free solders under different strain rates basically remains unchanged. The hardness increases as strain rate increases, indicating the strain rate hardening effect of viscous solders. During the holding stage, creep displacement increases with increasing strain rate during loading, while the creep strain rate firstly declines sharply and then stabilizes. Effects of stain rate on the mechanical properties of lead-free solders was systematically studied, providing valuable information for the reliability evaluation of lead-free solder joints in the service process.
  • Growth Kinetics Analysis of Al2O3 in CuAl2O3 Composites
    ;;; ;;
    . 2015, 46(01): 8-0.
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    The growth kinetics behaviors of Al2O3 particles in CuAl2O3 composites prepared by spray deposition internal-oxidation method were investigated by analyzing the reaction of aluminum and oxygen on the surface of a copper- aluminum alloy and calculating the precipitation amount of aluminum in the copper- aluminum alloy, the diffusion rate of aluminum in copper matrix and the size of Al2O3 particles. It is indicated that the growth kinetics of Al2O3 particles in the spray deposition internal-oxidation process follows a parabolic law, the reaction of aluminum and oxygen on the surface of the copper-aluminum alloy is controlled by aluminum diffusion, and the growth of Al2O3 particles is influenced by the content, diffusion rate and location (grains or grain boundaries) of aluminum in the copper-aluminum alloy. The calculated size of aluminum oxide particles agrees with the measured one.
  • Underwater Acoustic Performance Simulation of Polyurethane / Epoxy resin Elastomer
    wei-hong SUN; ;;
    . 2015, 46(01): 9-0.
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    An underwater acoustic model of polyurethane / epoxy resin (PU / EP) elastomer was established based on the acoustic boundary conditions, The influences of the PU / EP elastomer's Young's modulus, loss factor and Poisson's ratio to its acoustic performance; the underwater acoustic property of PU / EP(70/30) elastomer was tested on underwater acoustic pulsetube system. The simulation results show that Larger modulus, suitably damping factor and higher Poisson ratio are the key to obtain low reflection and high acoustic absorption performance. The underwater acoustic test results showe that the average acoustic absorption coefficient of PU / EP (70/30) elastomers is 0.39, the maximum absorption coefficient is 0.42, and the reflection coefficient over the entire frequency range of less than 0.4, it can be used as acoustic absorbing material matrix. And the numerical examples show the experimental results of PU/EP elastomer are basically consistent with the acoustic model simulation results.
  • Effects of Rapid Quenching and Annealing on Structure and Magnetostriction of Fe83Ga17Ce0.8 Alloys
    Zhanquan Yao;xiao tian
    . 2015, 46(01): 10-0.
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    Rare earth Ce doped Fe83Ga17Ce0.8 as-cast alloy was prepared by non-consumable vacuum arc melting furnace using high purity elements under a protective argon atmosphere and then rapidly quenched at 6 m/s. Finally, the Fe83Ga17Ce0.8 quenched alloy was annealed at 1223 K for 5 h. The effects of rapid quenching and annealing on structure and magnetostriction property of Fe83Ga17Ce0.8 alloys were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and magnetostriction measurements, respectively. The results showed that the Fe83Ga17Ce0.8 as-cast alloy is composed of the Fe(Ga) solid solution phase with bcc structure and a small amount of CeFe2 secondary phase. However, the Fe83Ga17Ce0.8 quenched alloy is mainly composed of the Fe(Ga) solid solution phase with bcc structure, a small amount of CeFe2 and unsymmetrical Fe3Ga phase with DO3 structure. After annealing, the CeFe2 phase of quenched alloy is conversed into Ce-poor rare earth phase of Ce2Fe17. The magnetostriction coefficient of quenched Fe83Ga17Ce0.8 alloy (382×10-6) is larger than that of the as-cast Fe83Ga17Ce0.8 alloy (356×10-6) and annealed Fe83Ga17Ce0.8 alloy (182×10-6) at the magnetic field of 557 kA/m.
  • Theoretical study of effective thermal conductivity of graphite foam/eutectic salt composite
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    . 2015, 46(01): 11-0.
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    In order to study the effective thermal conductivity (ETC) of the graphite/eutectic salt composite, a cubic unit cell model is proposed in this paper. The cubic structure is comprised of the six plates which has one hole in the center. This model has a good ability to accommodate different structure in the composite through changing the thickness of plate and the diameter of the interconnected pore. Firstly, the ETC of graphite/air composite is derived and comparisons of the results between the proposed model and published data in the literature show good agreement. So the validity of the current model is verified. Secondly, the ETC of graphite foam/eutectic salt in the different porosity is calculated. Finally, the effect of the diameter of the interconnected pore on the overall ETC is analyzed. The results show that with the increase of porosity, the ETC of the composite is on the decline. The solid graphite skeleton has great promotion effect on the thermal conductivity of eutectic salt. The effect of the interconnected pore diameter on the overall thermal conductivity decreases gradually, when the porosity increases.
  • Preparation and Properties of Lanthanum Doping TiO2／quartz sand composite photocatalyst
    . 2015, 46(01): 12-0.
    Abstract ( ) Knowledge map Save
  • Preparation and characterization of Si-Ti composite microparticles with UV-induced wettability conversion for easy-clean sunscreen
    ;Tao Meng
    . 2015, 46(01): 13-0.
    Abstract ( ) Knowledge map Save
    A new type of SiO2-TiO2 composite microparticles modified with trimethyl chlorosilane has been prepared as sunscreen, using the convenient, low-cost sol-gel method and layer-by-layer technique. Transmission electron microscope (TEM) and x-ray photoelectron spectroscopy (XPS) were used to characterize the morphology and chemical composition of the microparticles. In UV-Vis tests, the modified composite microparticles have showed significantly higher UV absorption than the unmodified and the pure TiO2 particles at 190~350nm. According to contact angle tests, the target microparticles were originally oleophylic and hydrophobic, and became oleophylic and hydrophilic after UV irradiation for several hours. In this study, the employment of composite microstructure produced good anti-UV property and also improved safety of use; the ability of UV-induced wettability convention on the surface of microparticles made cleaning a lot easier, highlighting the promising application of the novel microparticles for sunscreen preparation.
  • Synthesis and Characterization of PAMAM Dendritic Waterborne Polyurethane
    Longfang RenZiDong GUO;
    . 2015, 46(01): 14-0.
    Abstract ( ) Knowledge map Save
    Abstract: The polyurethane prepolymer was prepared in which the isophorone diisocyanate (IPDI), polycarbonate glycol (PCDL), diethanolamine (DEA), castor oil (C.O.) and 2,2-Dimethylol propionic acid (DMPA) were as raw materials, the dibutyltin dilaurate(DBTDL) was as catalyst. The polyurethane prepolymer was grafted on 1.0generation of polyamide-amine (PAMAM), and then a new type of dendritic waterborne polyurethane was synthesized. The synthesis conditions were optimized by single factor analysis method. The optimum conditions were that the prepolymerization reaction temperature was 80℃, the temperature of chain extension reaction was 75℃, the dosage of DBTDL was 0.08% and the dosage of DMPA was 6%. The product took on good water dispersibility. The products were characterized by Fourier transform infrared spectroscopy (FT-IR) and Thermogravimetric Analysis (TGA), its crystallization degree was determined by XRD and the water resistance and tensile strength of the film were tested too. The results showed that its bibulous rate was 12.1%, the tensile strength was 16.2 MPa and the thermal decomposition temperature was 205 ℃.
  • Simulation of effect of reinforcement particles on grain growth during laser melt injection based on CA
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    . 2015, 46(01): 15-0.
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    Based on the cellular automaton method, the definition of Moore neighbor type and the grain growth theory, a model of simulation for the grain growth process was established, which simulated the influence of the SiC reinforcement particles and 316L stainless steel reinforced the surface of magnesium alloy by laser melt injection. Many factors such as grain boundary mobility and grain boundary energy were considered in the model. Simulated the influence of different volume fraction and size of reinforcement particles on the grain growth process were obtained. The results show that: the grain growth process can be simulated very well by the method, the grain growth index can be obtained as 0.42; the higher volume fraction of the particles, the slower the speed of the grain growth, the smaller grain size; the smaller the particles size is, the slower the grain grows, the smaller grain size and the microstructure is more uniform.
  • Effects of bias-induced stress on AlInN/GaN high electron mobility transistors
    . 2015, 46(01): 16-0.
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    Drain current collapses under DC-bias-induced stress in passivated InAlN/GaN high electron mobility transistor grown on sapphire substrate were investigated. The experimental results indicated that the degradation of DC characteristics occurred after both the off-state stress and on-state stress, and the degradation degree increases with the accumulation of bias voltage and time. Theoretical analysis and device simulation results shown that the drain current collapse under the off-state stress was due to the virtual gate caused by surface state, while the collapse mechanism under the on-state stress was dominated by the hot-electron effect. In addition, we found that the current collapse under bias-stress was a reversible process. The degraded current can almost restore to the original values after ten days in the absence of any external exciting source.
  • The effect of dendritic-linear polymer PAMAM-AGE on the properties of wet blue leather
    . 2015, 46(01): 17-0.
    Abstract ( ) Knowledge map Save
    The dendritic-linear polymer poly(amido)amine-graft-alkyl glycidyl ether (G1 PAMAM-AGE) has been synthesized by the reaction of poly(amido)amine and alkyl glycidyl ether under alkaline conditions in isopropanol. The structure, grafting rate and average particle size of G1 PAMAM-AGE were investigated by FT-IR，1H NMR and laser?size instrument. The results show that the grafting rate is 85% and the G1 PAMAM-AGE emulsion exhibits good stability and the average particle size (APS) is 15.5 μm. The influence of the PAMAM-AGE on the structure, thermal stability and mechanical properties of the wet blue leather were investigated by IR, SEM and TG. The results indicate that the introduced PAMAM-AGE molecules are linked with the collagen fibers by strong interaction, which make the collagen fibers sticking together and improve the thermal stability and mechanical properties of the treated wet blue leather.
  • Corrosion monitoring of Fe-C fiber Bragg grating corrosion sensor at simulated marine environment
    Xing ZHENG
    . 2015, 46(01): 18-0.
    Abstract ( ) Knowledge map Save
    Fiber Bragg grating corrosion sensor based on Fe-C film with the similar composition of carbon steel was studied in this paper. Fiber corrosion sensor and electrochemical method were compared for corrosion monitoring in 3.5% NaCl solution. EDX, xrd and SEM were investigated on Fe-C film, sensor’s structure and principle were introduced. The experiment result shows fiber corrosion sensor has the biggest shift of 430pm in 2.5d corrosion; After 10d corrosion film falls off, corresponding to the decrease of wavelength. Compared to electrochemical method, fiber Bragg grating corrosion sensor shows dominance in long-term monitoring; it can get the time, speed and degree of corrosion, which has great significance in online monitoring of carbon steel.
  • Preparation and dielectric property of SiO2 surface coating modified BaTiO3/polyimide composite film
    Ya-Jun WANG ;;
    . 2015, 46(01): 19-0.
    Abstract ( ) Knowledge map Save
    Polyimide (PI) was chosen as the matrix of the composite, barium titanate/polyimide (BT/PI) nanocomposite films were prepared with in situ polymerization. In order to improve the dispersion and the physical-chemical properties of BT surface, barium titanate was modified by SiO2 coating and modified barium titanate/polyimide (BT/PI) nanocomposite films were prepared. The prepared modified BT was characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), and the dielectric properties of the composites were characterized in detail. It was shown that surface modification with SiO2 is the physical effect and there were no new substances forming. When BT was modified by 5% SiO2, the dielectric constant of the composite film was 21.8 (103 Hz), the loss tangent 0.00521, breakdown strength 76 MV?m-1, energy storage density 0.56 J?cm-3. The BT surface coating modification by SiO2 is beneficial to the dielectric properties of the BT/PI composite film.
  • The effect of reaction temperature on the micro-nano structure and the capacitance properties of cryptomelane-type manganese oxide
    fen ran ;;;;;;;;
    . 2015, 46(01): 20-0.
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    In this article, the uniform cryptomelane-type manganese oxide with an octahedral molecular sieves structure was prepared under mild hydrothermal condition; the effects of hydrothermal temperature on the micro-nanostructure and supercapacitance properties of manganese dioxide were studied in detail. The structures were characterized by SEM, XRD and TEM; and the supercapacitive behaviors were investigated with cyclic voltammetry, galvanostatic charge and discharge tests. The experiment results suggested that: the prepared nanoparticles can be self-organized into dendritic nanostructures, and the nanocluster arrays are composed of nanoneedles or tetragonal prism nanorods; With the increase of reaction temprature, the crystal morphology of manganese oxide was gradually improving, and was trasformed from nanoneedles to tetragonal prism nanorods; The capacitance of MnO2 electrode was a combined contribution of electrical double-layer capacitance and pseudocapacitance, and the best specific capacitance value of MnO2 electrode was 603 F/g corresponding to the charge/discharge current density of 5 mA/cm2; With the increase of reaction temperature ranging from 100-180℃, the specific capacitance of manganese oxide gradually decline.
  • Study on the Construction and Reliability of Back-Gate Mono-Layer Graphene Field Effect Transistor
    Xin-Li GUO
    . 2015, 46(01): 21-0.
    Abstract ( ) Knowledge map Save
    High-quality mono-layer graphene films were prepared by use of the technique of low pressure chemical vapor deposition (LPCVD). The as-prepared graphene was used to construct a back-gate mono-layer graphene field effect transistor by a simple process i.e.: The as-prepared mono-layer graphene was firstly transferred onto the surface area of SiO2/Si substrate covered with two parallel arranged heat release tapes with a gap distance ~500um. The graphene strip (~10000 um×500um) closely combined with the SiO2/Si substrate was obtained by heating and cutting. Finally, the Au electrodes were deposited on the surface of graphene strip by use a mask. The results of electrical properties measurements showed that the graphene strip was in good ohm contact with Au electrodes. The hole mobility of graphene was up to 735 cm2V-1s-1 at room temperature and the graphene exhibited an unique bipolar characteristic. The hysteresis behaviors in the transfer characteristics curves of back-gate mono-layer graphene field effect transistors were observed and become more obvious with the increase of gate voltage, which exhibited high properties reliability.
  • Numerical simulation on electrical property of carbon nanotube cement-based composites
    Jian-Wei NIU
    . 2015, 46(01): 22-0.
    Abstract ( ) Knowledge map Save
    Abstract: The finite element model of carbon nanotube (CNT) cement-based composites is set up by using ANSYS 12.0 and Monte Carlo method. The effects of aspect ratio, diameter and concentration of CNT on the effective electrical resistivity of composites are investigated with finite element analysis method. Furthermore, the effective resistivity calculated by finite element analysis and the resistivity tested in experiment are respectively regressed through General Effectvie Media equation. The results of numerical simulation show that the resistivity calculated with finite element analysis consists with the resistivity tested in experiment. This proves that using finite element analysis to simulate electrical property of CNT cement-based composites is feasible. The effective resistivity of CNT cement-based composites decreases with the increasing of the CNT concentration and CNT aspect ratio, and the decreasing of the CNT diameter. The curve changes regressed by General Effectvie Media on the numerical results of the effective resistivity calculated with finite element analysis and the results of the effective resistivity of the CNT cement-based composites tested in experiment are consistent.
  • Study on the mechanism of micro-slip for γ-TiAl alloy with single crystal
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    . 2015, 46(01): 23-0.
    Abstract ( ) Knowledge map Save
    Aimed at the deficiency of the study about the mechanism of micro-slip for γ-TiAl single crystal. The model of crystal slip for γ-TiAl single crystal with uniaxial tension was established in this paper. The Schmid factors along different slip directions were calculated based on the geometry relationship in model and the slip directions given by Weiss Zone Law. The result that crystal will be easier slip along and than other directions was obtained by comparing the calculated results. Besides, the result that critical value of external tensile strain under the given case of double slip system is 0.633 was got. Furthermore, the mechanism for micro-slip of γ-TiAl alloy with monocrystal under uniaxial tension given in this paper is correct, which was verified by numerical simulation.
  • Preparation and anti-fouling properties of the positively charged P(MMA-co-BVIm-Br)/PVDF blend membranes
    Xu-Min MA; ;;Li-Guang Wu
    . 2015, 46(01): 24-0.
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    The amphiphilic poly(ionic liquid) copolymer P(MMA-co-BVIm-Br) was synthesized by radical polymerization process. P(MMA-co-BVIm-Br) was used to prepare P(MMA-co-BVIm-Br)/PVDF blend membranes. Infrared spectroscopy(FTIR),contact angle, zeta potential instrument and scanning electron microscopy (SEM) were used to characterize the surface chemical structure and the morphology of the blend membranes. The protein separation properties of blend membranes were also studied. The results indicated that the pH value of the solution would change the charged property of the protein, which would affect the separation properties of the membranes. When the pH value of solution was below the isoelectric point of the protein, the rejection, reversible fouling rate and the flux recovery ratio of the blend membranes were all increased. These phenomena suggested that the blend membranes had good charged and anti-fouling properties.
    • 工艺 技术
  • Preparation and thermal properties of Graphene oxide/ MF composites
    Jian-Chuan WANG;;
    . 2015, 46(01): 25-0.
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    Graphene oxide/ Melamine-formaldehyde resin（GO/MF）composites were prepared by in situ polymerization. The Structure and morphologies of GO and composites were investigated using Fourier transformation infrared spectroscopy（FTIR）， Atomic force microscope（AFM）and scanning electron microscope（SEM）. The thermal properties of samples were studied by thermal gravimetric analysis (TGA). The result showed that thermal stability of the composites with GO were improved. Thermal conductivity of the GO/MF composites with 0.84 wt% GO could be increased by 32.0% compared to MF without GO.
  • Morphology Effect of Polished Copper on the Graphene Quality by CVD
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    . 2015, 46(01): 26-0.
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    Copper is a widely used catalyst for graphene synthesis by Chemical Vapor Deposition (CVD), whose surface quality has great influence on the graphene quality. Electrochemical polishing is an important method of pre-treatment of the metal surface morphology. In this paper, we comprehensively discussed the relationship between process parameter of electrochemical polish with surface morphology and graphene quality. It is found that, Compared with the graphene grown on the unpolished copper foil, the qualities of the graphene grown on the polished copper foil improved significantly。And, at certain current density range, the surface morphology is in direct ratio with the polishing voltage., Correspondingly the graphene has less defects, better monolayers, transmittance and conductivity.
  • Formation Design and Performance of Concrete Filled Steel Tube Applied in Ganhaizi bridge
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    . 2015, 46(01): 27-0.
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    Abstract: According to winter concrete construction requirements and raw materials properties of Ganhaizi bridge, sodium nitrite and ethylene glycol were used to form organic and inorganic coordination antifreeze, frost resistance core concrete with outstanding package, excellent fluidity and good self-compacting ability was prepared. The laws of later strength evolution of concrete filled steel tube which pouring and maintenance at low temperature were investigated. Scanning electron microscope (SEM) was used to analyze the micro-morphology features of core concrete. It was confirmed that core concrete and concrete filled steel tube short column which manufactured at the low-temperature have a high early strength, and the later strength would steady grow when the temperature rise. The concrete prepared have prominent working performance and mechanical properties at low temperature, and good frost resistance, which would meet the winter concrete construction requirements of Ganhaizi bridge.
  • The preparation and properties of Inorganic Wheat-straw Particleboard
    . 2015, 46(01): 28-0.
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    With wheat straw and inorganic glue as main raw materials, inorganic wheat-straw particleboard was prepared by moulding pressing technology. The effect by adding different level of wheat straw（Glue-straw ratio） and density of board on physical and mechanical properties of inorganic wheat-straw particleboard was studied. X-Ray diffraction (XRD), Thermogravimetric Analyzer(TGA) and Scanning Electron Microscope(SEM) were used to analyze influencing mechanism of a different level of Glue-straw ratio and density of the board. The results show that inhibition effect of wheat straw to hydration reaction of inorganic composition decreases with the increasing Glue-straw ratio during board maintenance. hydration reaction speed of inorganic composition in inorganic wheat-straw particleboard was increased, and the reaction carries out more completely, produced more complete crystallization and more inorganic glue. IB of inorganic wheat-straw particleboard increases gradually and TS of that decreases gradually; MOR and MOE of that firstly increase and then decrease, wheat straw have a good distribution in the particleboard. Properties of bonding interface between wheat straw and inorganic adhesive became better as well as good mechanical properties were formed, interface friction and thermal stability were increased, hydration reaction speed of inorganic composition in inorganic wheat-straw particleboard was increased and produced more inorganic glue with the increase of particleboard density. IB and MOR, MOE of inorganic wheat-straw particleboard increases gradually and TS was decreased. The interaction between the crystalline particles were increased，mechanical properties, interface friction and thermal stability were increased too with the increase of particleboard density.
  • Preparation of Supported Pd Catalyst and Its Catalytic Activity for methanol Oxidation
    xue-qiao ZHANG ;
    . 2015, 46(01): 29-0.
    Abstract ( ) Knowledge map Save
    A series of Pd+M（M=MgO、CaO、SrO、BaO）catalysts was prepared by impregnation method. Specific surface area measurements (BET), CO-chemisorption, X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR), were used to characterize the effect of Alkaline Earth Metal on the physicochemical properties of the catalysts. Their catalytic activity towards methanol oxidation was evaluated. The results show that the addition of Alkaline Earth Metal increases palladium highly dispersed and enhances the amount of active oxygen. X-ray photoelectron spectroscopy (XPS) result shows that the electron effects between Pd and support is improved. It is favorable for maintaining Pd in a higher oxidized state and increasing the concentration of Ce3+on the catalyst surface, which led to a better redox property. The excellent redox property helped to improve the catalytic activities toward methanol over Pd-based catalysts. The aid catalytic activity is following the order: BaO > CaO > MgO > SrO. Key words: palladium; methanol; catalytic oxidation; Alkaline earth promot
  • Study on the evolution of microstructure and properties in preparing Fe-6.5%Si alloy by means of PVD method
    Guang-Ke TIAN ;;
    . 2015, 46(01): 30-0.
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    Si-enriched films were deposited by DC magnetron sputtering onto both surfaces of low-Si steel substrate with 0.35 mm thickness, subsequent annealing in vacuum at 1180℃×1h results in penetration of Si into the substrate. The microstructure and Si concentration were investigated by optical microscopy and scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The phases were identified by X-ray diffractometer (XRD) and transmission electron microscope (TEM). With the increment of Si content by penetration of Si, the substrate still exhibited??-Fe(Si) bcc and the lattice constant decreased slightly. After 4 rounds of the Si-enriched process, the alloys demonstrated uniform distribution of Si with 6.5%. Iron losses of the prepared Fe-6.5% Si alloy were declined about 40-50% comparing with the starting substrate.
  • The effect of Sodium tetra borate on the deposition rates and corrosion resistance of electroless Ni-P amorphous coating
    FU Chuan Qi
    . 2015, 46(01): 31-0.
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    Abstract: Sodium tetra borate (Borax) promoted Ni-P amorphous coating were prepared on the 45# carbon steels specimens by electroless deposition. The surface morphology and structure of the coatings were analyzed by scanning electron microscope (SEM) and X-ray diffraction, and the deposition rates, the element of P content, porosity in the coating and the fouling rates of the composite coatings were investigated. The results indicate that added significantly Sodium tetra borate into the bath increased density of coating and deposition rates. With the increasing Sodium tetra borate content, the deposition rates has a rising trend, gradually the trend of P content reduce. When the content of Sodium tetra borate is larger than 2.5 g?L-1 solution of stability will be greatly reduced. The content of sodium tetra borate is 2.5 g?L-1 plating speed to a maximum of 21.35 μm?h-1, and the content of P is 14.3%. The addition of Sodium tetra borate has little effect on the corrosion resistance of the coating. In contrast, the increasing of planting speed that can improve the cycle of coating makes better economic efficient and using value.
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