28 February 2014, Volume 45 Issue 04

    

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研究 开发
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  Study of Electroless Ni/Sn Plating on Kevlar Fiber

  ;;Duan Yong Hua;Fang Dong Sheng

  . 2014, 45(04): 1-0.

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  Electroless coating of Ni/Sn on Kevlar fiber and its metallization were operated. The surface appearance、composition and phase of Kevlar were investigated by means of SEM, EDS and XRD. The corrosion resistance、adhesion strength and electrical conductivity was also measured. The results showed that the pretreatment is necessary for getting clean, catalytic and favorable layer. The compact Ni-layer could be obtained by plating 120min at pH 6, the adhesion strength is excellent and coating thickness reaches 752nm. The coating thickness of the compact Ni/Sn-layer obtain by plating 150min at pH 0.8~1.2 is 1.4μm and combined well with Kevlar. The fibers of electroless Ni/Sn have a good corrosion resistance、adhesion strength and electrical conductivity, it could well be used for electronic component and electromagnetic shielding.
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  Research on preparation and microstructures of Mg-Zn-Sr ternary alloys by molten-salt electrolysis

  . 2014, 45(04): 2-0.

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  Using Mg-ωt33% Zn alloys as the cathode,graphite as anode,to conduct electrolysis by liquid cathode alloying form KCl-SrCl2 melts at 740 ℃,and casting the reaction liquid at 670℃ to prepare the Mg-Zn-Sr alloys.After turning the casting product,samples of the alloys were analyzed by means of X-ray fluorescence, optical micrograph(OM),scanning electron microscopy (SEM),energy dispersive spectrometry(EDS) and X-ray diffraction(XRD),and compared with the cathode alloys.The results show that the reaction prepared Mg-Zn-Sr ternary alloys successfully, the mass fraction of Sr is 1.6279%,and Sr refine the cathode alloys. Compared to the microstructures of molten Mg-Zn-Sr alloys,and found that the electrolytic Sr can refine microstructures better.
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  Study on Selective Acid Hydrolysis of Cellulose Aggregation Structure Catalyzed by Fe3+

  Hang He

  . 2014, 45(04): 3-0.

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  It was a key technology that degraded the amorphous region and retained the crystalline region in the process of preparation of microcrystalline cellulose.It was studyed that woodpulp was acid hydrolyzed catalyzed by Fe3+.The crystal structure,chemical structure and microstructure of hydrocellulose were characterized by XRD,FTIR,SEM. The results indicated that cellulose was promoted by Fe3+ during the acid hydrolysis at the mild condition and strengthening condition. The yield of hydrocellulose was 87.28% and the crystallinity was 62.89% under the strengthening condition.XRD results indicated that the crystal structure did not change during the acid hydrolysis of cellulose.FTIR analysis showed that the hydrocellulose had the same functional groups as the cellulose and the contents of hydrogen bond had changed which led to the change of the absorption peak.
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  The growth of large-size organic thin crystals by solution process for the application on organic field effect transistors

  Yu XIAO;;

  . 2014, 45(04): 4-0.

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  The authors have adopted the improved co-solvent method to prepare the large-size thin crystals of semiconducting 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-PEN). The thin crystals show the lateral size as large as a few millimeters and the thickness in a range from 90 nm to 700 nm. Polarized optical microscopy confirms their single crystalline nature and it is found that the size and thickness of the thin crystals increase with the increasing of the solution concentration. X-ray diffraction and SEAD analysis reveals that the crystals exhibit high molecular orientation and high structural ordering. The field effect transistors (FET) based on the TIPS-PEN thin crystals exhibit a high hole mobility of 0.39 cm2V-1s-1, two orders of magnitude larger than those from the cast thin films. The hole mobility is found to increase with decreasing the thickness of the crystals.
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  The Trend of Microdrills for Printed Circuit Boards

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  . 2014, 45(04): 5-0.

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  More Printed Circuit Boards(PCB) would be produced with the development of electronic industry. And more microdrills for PCB woluld be needed. This paper describes the development of microdrill material. And The Development of the Manufacturing Technique was discussed in details. Our country should do more work on the study of the rheology of powder extrusion,new formagen, forming process, coating technology and equipment matching technology.
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  Review on compressive deformation of bulk metallic glasses

  Xin-cai LIU;PAN Jing

  . 2014, 45(04): 6-0.

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  In this paper, the compressive deformation behavior, samples surfaces and fracture microstructure characteristics have been reviewed at different temperatures and strain rates for bulk metallic glasses (BMGs). BMGs behave like Inhomogeneous brittle fracture, non-Newtonian fluid and Newtonian fluid mode respectively at reduced compressing temperature tr=T/Tg ranging of 77K/Tg ≤tr
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  Modification of a hyperbranched polycarbosilane with boron and its polymer-to-ceramic conversion

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  . 2014, 45(04): 7-0.

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  A boron-modified AHPCS was prepared by chemical reactions between allylhydridopolycarbosilane (AHPCS) with dimethylamine borane (DMAB), and then cross-linking at 170℃, followed by pyrolyzing at high temperatures to afford SiC-based ceramics. The cross-linking and polymer-to-ceramic conversion of the boron-modified AHPCS were characterized by FTIR, TGA and XRD. The results indicate that the cross-linking of AHPCS is improved, involving hydroboration reaction between vinyl groups of AHPCS and B-H groups of DMAB, and dehydrocoupling reaction between Si-H groups of AHPCS and B-H groups of DMAB. As a result, the ceramic yield of the B-modified AHPCS is significantly enhanced. Moreover, the introduction of boron inhibits the crystallization of β-SiC at high temperatures obviously.
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  Preparation of Ag/graphene nanocomposite and its SERS effect on methyl anthranilate

  ;Tianhao Ji;;

  . 2014, 45(04): 8-0.

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  Ag-deposited reduced graphene oxide (r-GO) nanocomposites, without any additional organic molecules, were obtained simply through two different preparation processes of ultra-violet reduction and hydrazine reduction. It has been demonstrated that particle-shaped Ag is formed on the surface of r-GO. Using ultra-violet reduction route, due to very slow reduction reaction, Ag particles on the r-GO surface exhibit relatively good dispersion and narrow size distribution with a diameter range of 25-80 nm. However, under hydrazine reduction, Ag particles show severely aggregation and wide size distribution with a diameter range of 20-130 nm due to fast reduction reaction. Based on the preparations, the surface-enhanced Raman scattering (SERS) spectroscopes of methyl anthranilate molecules on a series of Ag-deposited r-GO samples were measured in detail, and the results show that such composites have high SERS effect on the organic molecules with an enhancement factor of an order of 108, in which the composite prepared from hydrazine reduction shows obviously higher.
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  Effect of SDBS on Electrorheological Properties of Gly-O-Ti Suspensions

  ; Xu-Feng DONG;;;min qi

  . 2014, 45(04): 9-0.

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  Sodium dodecyl benzene sulfonate (SDBS) modified Gly-O-Ti particles were prepared via a hydrothermal method. The influence of SDBS on properties of Gly-O-Ti particles-based electrorheological (ER) fluids was investigated experimentally, and the mechanism was discussed. The results indicated that adding suitable amount of SDBS could improve the yield stress and decrease the leakage current density of Gly-O-Ti particles-based ER fluids.
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  Effect of Polyethylene Glycol Molecular Weight and Concentration on the performance of Polyethersulfone Hollow Fiber Ultrafiltration Membranes

  Kui Li;Qi Zhu;Huiying Chen;;ma-tai DING;

  . 2014, 45(04): 10-0.

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  The effect of polyethylene glycol (PEG) molecular weight and concentration on the performance of PES hollow-fiber membranes, fabricated by phase inversion process, was investigated. The results demonstrated that the rejection and tensile strength decrease gradually when the PEG molecular weight increases from 600 to 20000. Meanwhile, the pure water flux first increases and then decreases, which reaches the maximum value of 177.41 L/h?m2 at the PEG molecular weight of 6000. In addition, with the increase of the PEG-6000 concentration from 4% to 10%, the pure water flux gradually increases, whereas both the rejection and tensile strength gradually decrease.
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  Preparation and controlled release properties of cell outer membrane mimetic structures of chitosan nanoparticles

  Ming GONG

  . 2014, 45(04): 11-0.

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  The cell outer membrane mimetic structures of nanoparticles were prepared using methacrylic acid (MA), 2-methacryloyloxyethyl phosphorylcholine (MPC) as monomer, potassium persulfate (KPS) and chitosan by template polymerization. The size distribution and structure properties of nanoparticles were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and Zeta potential. The drug release properties of nanoparticles were estimated by doxorubicin in vitro release experiment. That cell outer membrane mimetic structures of nanoparticles may have potential applications in the ?elds of gene therapy and drug delivery. The controlled release properties had been an important academic significance on the study of outer cell membrane structures of nanoparticles.
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  The preparation and thermal properties of calcium alginate/gelatin (semi) IPNs crosslinked with oxidized sodium alginate

  ;;;Chuan-jie ZHANG;;Ping ZHU

  . 2014, 45(04): 12-0.

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  Calcium alginate/gelatin (semi) interpenetrating polymer networks (IPNs) were prepared with oxidized sodium alginate as a crosslinking agent. The structure and thermal stabilities of (semi) IPNs were characterized by Fourier transform infrared spectrometer (FTIR) and thermogravimetric analysis (TGA), respectively. And in contrast with calculated TGA data, the reactive mechanism in the blending process was studied. Compared with the thermal stabilities of (semi) IPNs crosslinked with glutaraldehyde, the results indicated that the thermal stabilities of (semi) IPNs crosslinked with oxidized sodium alginate were similar to those crosslinked with glutaraldehyde. And oxidized sodium alginate could be instead of toxic glutaraldehyde to crosslink the calcium alginate/gelatin (semi) IPNs system, and physical and/or chemical reaction may take place in the blending process.
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  The Effect of deposition atoms’ kinetic energy on three dimensional growth of BaTiO3 thin film by Monte Carlo

  Guo-feng XIE

  . 2014, 45(04): 13-0.

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  Considering the characteristics of perovskite structure, we proposed a Kinetic Monte Carlo method based on binary lattice system. Different from the traditional SOS (Solid-On-Solid) algorithm, the deposition, diffusion and bonding of adatoms were considered in this method. This Paper applied the method to simulate the homoepitaxial layers growth of BaTiO3 thin film, and analyse the effects of deposition atoms’ kinetic energy on the nucleation ratio, island density, three dimension growth mode, vacancy ratio and bonding ratio. The results are helpful to fabricate ferroelectric thin films with high performance.
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  Crystallization Behavior and Magnetic Properties of Fe64Nd7B25Nb4 Alloys Prepared by Copper Mold Casting

  . 2014, 45(04): 14-0.

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  Fe64Nd7Nb4B25 bulk amorphous alloy was prepared by copper mold casting. The structure, crystallization behavior and magnetic properties were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and vibrating sample magnetometer (VSM). The results showed that Fe64Nd7Nb4B25 alloy with amorphous structure exhibited good soft magnetic property, while the alloy after crystallization treatment exhibited hard magnetic property. When annealed at 963 K, the values of intrinsic coercivity (iHc) and remanence (Br) reached 560.2 kA/m and 42.6 Am2/kg, respectively. With increasing the annealing temperature, the magnetic property got worse.
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  The influence of high-temperature rapid treatment on the compressive properties of Cu-based amorphous alloys

  Ya-juan ZHANG;

  . 2014, 45(04): 15-0.

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  Cu50Zr42Al8 amorphous alloy was prepared by copper mold casting process, then high-temperature treatment at different temperatures was carried out. Structural, thermal and compressive properties of the annealed BMGs were studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscope (SEM) and compressive test methods. The results indicate: the sample treated at 873K didn’t form new phase, the other samples formed Cu10Zr7 and AlCu2Zr new phases, and with the treatment temperature increasing, the volume fraction of precipitated phase increased; The strength and plasticity of as-cast specimen is the best, and with the heat treatment temperature increasing, fracture strength firstly increase and then decrease. The sample treated at 1148K has the lowest fracture strength, the 1123K has the highest in the samples treated. In addition to the as-cast specimen, only the sample treated at 1198K shows plasticity with the plastic strain 0.83%.
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  Microstructure and mechanism of reinforced and toughened cement composites by nano graphene oxide

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  . 2014, 45(04): 16-0.

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  Graphene oxides (GO) with different oxygen content were prepared by oxidization and ultrasonic dispersion. The effect of oxygen content and dosage of GO and hydration time on microstructure and mechanical properties of cement composites were investigated. The results indicated that GO can regulate formation of flower-like hydration crystals and increase remarkably the tensile and folding strength of the corresponding cement composites. The results suggested that GO has template role in forming cement hydration crystals, which can regulate the microstructure of cement hydration products and improve toughness of cement composites. A possible mechanism of GO mediated formation of flower-like crystals was also presented in this paper. The research result provides a new pathway to significantly improving the toughness of hardened cement paste and has significant practical applications.
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  Advances on AgInS2 quantum dots

  XIANG Weidong ;;;

  . 2014, 45(04): 17-0.

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  Recently, the newly environmental friendly I-III-VI semiconductor quantum dots (QDs) AgInS2 has received significant progress by virtue of its excellent properties of quantum dots and the advantage of low-toxic. Therefore, it is expected to replace Cd-based quantum dots in various applications. Focus on the advances at home and abroad, the status and the existing problems of AgInS2 quantum dots are summerized and discussed. Furthermore, the prospects of the related research are presented.
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  The influence of thermo-mechanical training on the shape memory effect and structure in Fe-Mn-Si shape memory alloy

  Guoqiu He

  . 2014, 45(04): 18-0.

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  Effect of the times of thermo-mechanical training on the shape memory of Fe-Mn-Si shape memory alloy was studied in this paper. The results show that with the increase of the number of training, alloy strain recovery rate rises to the highest 1.95% after three training sessions and then begins to decrease. Microstructure analysis showed that the rise of it in the initial stage could be attributed mainly to thermo-mechanical training, inducing martensitic preferred orientation and resulting in a uniform distribution of martensite which is running parallel with each other with few of crossover. While the decrease of the recovery rate is primarily due to the serious dislocation tangle forming inside the alloy matrix, which leads to irreversible plastic deformation.
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  The influence of particle size on piezoresistivity and dielectric properties of Nickel/silicone rubber composite

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  . 2014, 45(04): 19-0.

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  Nickel-silicone rubber composites were prepared using nickel powder of different sizes (0.15?m, 0.2?m, 0.3?m, 3?m, 18?m) and silicone rubber at the ratio of 2.8:1 by weight. The effect of pressure on the piezoresistivity and dielectric properties of the composite samples at room temperature were measured. The results show that the piezoresistivity of the nickel-silicone rubber composites decreases abruptly as nickel particle size is reduced to less than 0.3?m. The ac conductivity, dielectric constant and loss of these composites become much lower and show little frequency dependence. In general, metallic particles would transform into insulator as size of the particles becomes very small, typically ~10nm. Our results suggest that there exists a size effect for Ni particles even at sub-?m range. Studying metal-polymer composites provides a simple and effective way in characterizing the size effect of metallic particles.
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  Structure and Properties of (0.84-x)Na0.5Bi0.5TiO3-0.16K0.5Bi0.5TiO3-xSrTiO3 Lead-free Piezoelectric Ceramics

  . 2014, 45(04): 20-0.

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  Bi-compensated (0.84-x)Na0.5Bi0.5TiO3-0.16K0.5Bi0.5TiO3-xSrTiO3(abbreviated as NBT-KBT-xST) lead-free piezoelectric ceramics were prepared by an ordinary sintering technique. The effects of different ST dosages on the structure and electrical properties of ceramic samples were investigated. The results indicate that full solid solution with a pure perovskite structure is formed after the ST is added. The phase structure of the ceramics at room temperature changed from rhombohedral to tetragonal with increased ST content, and the morphotropic phase boundary(MPB) of the system locates in the composition range of 0.03 ≤ x ≤ 0.04, which exhibit good ferroelectric and piezoelectric properties. When x = 0.04, the ceramics exhibit the best performance: the piezoelectric constant d33 = 156 pC/N, planar coupling factor kp = 0.29, relative dielectric constant εr = 1116, dielectric loss tanδ = 4.1%, remnant polarization Pr = 30.5 μC/cm2, coercive field Ec = 23.9 kV/cm. The temperature dependences of dielectric and ferroelectric properties suggest that the ceramics may contain both the polar and non-polar regions at temperatures above Td.
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  The effect of SiO2 particle size on the performance of magnetorheological fluids

  ; ;Zhi-De HU

  . 2014, 45(04): 21-0.

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  A novel mineral oil-based magnetorheological fluids was prepared with carbonyl iron powder for magnetic particle and SiO2 particles as thixotropic agent，The effect of particle size of SiO2 on magnetorheology, stability and tribological performance of magnetorheologicalfluids was studied by measuring the zero field viscosity, rheological curve, sedimentation rate, and the friction coefficient et al.. The results indicated that the SiO2 with middle particle size as a thixotropic agent could significantly improve the zero-field viscosity, and field-induced shear stress was enhanced with SiO2 in small particle size. Sedimentation stability was improved significantly with the increase of the particle size of SiO2, but the dispersion performance was poor with larger apparent viscosity of sediment. In addition the magnetorheological fluid showed good anti-friction performance with average SiO2 particle size in 15nm and 100nm.
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  Preparation and properties of blast furnace slag wool insulation board

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  . 2014, 45(04): 22-0.

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  Traditional insulation materials has the disadvantage of poor fire resistance and destructive to the environment, for example, organic insulation board . In this paper, by choosing the blast furnace slag as the main raw materials and adding water glass, polyvinyl acetate adhesive and hydrophobic agent, the non-combustible blast furnace slag insulation board with low heat shrinkage and high water resistance was produced. The mechanical properties、thermal stability、water absorbing capacity and hydrophobic of the insulation board with different additives was studied. Compression strength and water absorption of the insulation board is found to correlate with mass ratio of water glass. It is also observed that polyvinyl acetate adhesive can enhance flexural strength of the insulation board. The wetting angle experiment indicates that a hydrophobic film is formed on the fiber surface due to the addition of hydrophobic agent, which increases the wetting angle between the insulation board and water, and improves the hydrophobic nature.
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  Synthesis and characterization of benzotriazole-alt- 3-alkylthiophene by metal complex catalyses method

  . 2014, 45(04): 23-0.

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  Alternating copolymers of benzotriazole and thiophene containing different alkyl side chain were prepared by metal complex catalyses method. The chemical structure and basic properties of obtained copolymers were characterized by 1H-NMR , FT-IR, UV-vis, Fluorescence Spectroscopy and Gel Permeation Chromatography. The obtained polymers can be solved easily in common organic solvents such as CHCl3and THF. UV-vs maximum absorbance in CHCl3 of these copolymers appeared about 433 nm、432 nm、415 nm respectively. Number average molecular weights (Mn) of the polymers about 0.57 ?104~0.49?104. The polymers showed better fluorescence characteristics and electrochemical activity.
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  Electromagnetic shielding effectiveness of cement based materials filled expanded graphite inserted by Ni- ferrite

  HUANG Shao Wen

  . 2014, 45(04): 24-0.

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  Abstract：The influence of expanded graphite and nickel ferrite (NiFe2O4) expansion graphite on electromagnetic shielding effectiveness (SE) of cement paste were researched in this paper. The SE value of cement paste filled different modified graphite was measured by a coaxial flange method. Results show that the SE of cement paste filled expanded graphite inserted by Ni- ferrite can be substantially increased in the whole testing frequency band. Especially, the SE of cement paste is obviously improved in the low frequency band (30 MHZ ~ 1000 MHZ) . The best SE of cement paste filled expanded graphite inserted by 15% Ni- ferrite is 26 dB.
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  In-situ raman measurements of PZT ferroelectric ceramics under a stress field

  ; ;Ying Zhang

  . 2014, 45(04): 25-0.

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  Polycrystal ceramics of Pb(Zr0.52Ti0.48)O3 with tetragonal phase and average sizes of uniformly distributed grains being 2～3μm were prepared through a conventional solid state route. In-situ Raman measurements on individual single grain and multiple single grains in subsequence were carried out under a stress field by employing a four-point bending load. The relative intensity ratios of optical modes at lower Raman shifts (IE(1LO)/IE(2TO) and IE+B1/IE(2TO)) under different applied stresses were calculated by normalizing peak intensity. The results revealed that the values of (IE(1LO)/IE(2TO) and IE+B1/IE(2TO)) decreased with the increases in the applied tensile or compressive stresses, while increased with the extension of applying time. The values of (IE(1LO)/IE(2TO) and IE+B1/IE(2TO)) varied with the alterations of applied stresses on different single grains. However, the peak position of Raman spectra remained unchanged.
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  Preparation of lipid-soluble drug microparticles by the supercritical fluid expansion depression- impinging stream technology

  JIANG Jing-zhi;Hai-Ting CUI

  . 2014, 45(04): 26-0.

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  The supercritical fluid expansion depressurization process was combined with the impinging stream technology. The feasibility of this technology to prepare lipid-soluble drug microparticles was investigated with rifampicin as model material. The influences of the operation parameters, including the pressure and temperature in the mixing vessel, the solution concentration, the solution feed rate and the temperature of the precipitator, on the particle diameter and diameter distribution were studied in detail. Results of this study indicate that, in comparison with the supercritical fluid expansion depressurization process, the rifampicin microparticles with more well-defined morphology, smaller particle diameter and narrower diamater distribution were preapred by the supercritical fluid expansion depression-impinging stream technology. When the impinging stream technology was applied the unfavorable factors of the supercritical fluid expansion depressization to affect the microparticle character were weakened. The microparticels with well distribution can be obtained in a wider operation range. In addition, the heat and mass transfer between liquid droplets and heat gas were enhanced and the drying effect of microparticle was improved obviously. The well dispersion microparticles were obtained at the 10℃ lower than the optimal precipitator temperature of the supercritical fluid expansion depressuzation. The energy consumption was reduced significantly.
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  Influence of solvothermal treatment temperature on oxidation modification of carbon/carbon composites with ZrB2 micro-particles

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  . 2014, 45(04): 27-0.

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  Carbon/carbon composites were modified with a borate sol precursor and ZrB2 micro-particles by a sol-gel/solvothermal method. The as-modified C/C composites were characterized by XRD, SEM, EDS techniques. The influences of the solvothermal treatment temperature on the phase, microstructures and anti-oxidation properties of the modified C/C composites were investigated. Results show that the surface of the modified composites is covered by a B2O3 continuous molten layer and ZrB2 micro-particles, also the internal micro-holes are occupied by B2O3 and ZrB2. The anti-oxidation property of the composites after modification improves with the increase of the solvothermal treatment temperature from 100℃to 180℃. The carbon/carbon composite modified by 180℃ exhibits the best anti-oxidation ability, which can effectively protect carbon/carbon composite from oxidation in air at 600℃for 6h with a weight loss of 26.4 mg?cm-2.
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  Effect of Sm doping on structure and electrochromic properties of TiO2 thin film

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  . 2014, 45(04): 28-0.

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  Taking Butyltitanate(Ti(OC4H9)4) and Samarium nitrate(Sm(NO3)3?6H2O) as main components, it used sol-gel method to prepare TiO2 thin film doped with Sm on ITO conductive glass substrate surface. The Sm doping molar ratios are 0, 2%, 5%,10% and 20%. Structural, thermogravimetric and electrochemical Properties were investigated by XRD, TG-DTA and Cyclic Voltammetry curves(CV).The result indicates that the TiO2 thin film doped with Sm has higher amorphous degree. When the doped amount of Sm is at 5%, the peak current of thin film reaches its maximum value with most powerful charge storage capability, injected charge density at 13.35 mC?cm-2，and cyclic reversibility K value at 0.92. When the heat processing temperature is at 250℃, the organic components in the thin film are almost completely decomposed and obtain the stable Sm doped TiO2 thin film.
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  Low-Cycle Fatigue Behavior of cast AlSi9Cu3 Aluminum Alloy

  Bin LIU

  . 2014, 45(04): 29-0.

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  Low-cycle fatigue behavior of cast AlSi9Cu3 aluminum alloy under different strain amplitudes were studied. Fatigue behavior were tested by MTS, the relationship between strain amplitude and fatigue life were revealed . Fatigue fracture were analyzed by optical and scanning electron microscope. The research results show that :under low-cycle fatigue loading condition ,the cast AlSi9Cu3 aluminum alloy can exhibit the continuous cyclic strain hardening or initial cyclic strain hardening followed by cyclic stability, and the bigger of strain amplitude, the higher of hardening rate; A single-slope linear relation between plastic strain amplitude, elastic strain amplitude and reversals to failure is observed from cast alloy ,the experimental results conform to the Coffin - Manson formula. Fatigue fracture of material observed by SEM, the width of the fatigue stripes is related to strain amplitude, fatigue damage is related to the strain amplitude also.