25 July 2010, Volume 41 Issue 07
    

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    研究与开发
  • . 2010, 41(07): 1-0.
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    Abstract: Spherical titania particles with colltrollable particle size were prepared by sol-gel synthesis with the addition of a salt solution. The particles were characterized by SEM, XRD, IR, TG-DSC, The influence of various kinds of salt solution and concentrations on the particle size and the size distribution were investigated respectively. At the same times, the growth mechanism of these titania particles with colltrollable particle size were simply discussed. The experimental results show that the particle size minished with increasing of the radius of the positive ions in the salt solution, the reason may be hydrated radius decreased with increasing of the radius of the positive ions;while the diameter of the titania particles becomes bigger with the increasing of the concentrations of the same kind of salt solution,this may be the diffusion layer becomes thin and crash becomes frequently.
  • Wang Hai Zhen
    . 2010, 41(07): 2-0.
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    Bismuth sodium titanate [Bi0.5Na0.5TiO3, BNT] fine powders can be prepared using tetrabutyl titanate, bismuth nitrate pentahydrate and sodium acetate anhydrous as starting materials by sol-gel method. The structure characteristics and microstructure of the synthesized powders were analyzed by XRD and TEM. Applying orthogonal experiment method, the influence of reaction temperature, pH and water volume on the grain size of final BNT powders were analyzed. It was founded that, the primary and secondary sequence affecting the grain sizes of the BNT powders is: water volume> pH> reaction temperature. The results show that when the reaction temperature is 60℃, value of pH is 4.5 and the water volume is 7.2ml, the grain sizes of the powders is about 200~350 nm.
  • . 2010, 41(07): 3-0.
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    MgO thin films were produced on Si(100) substrates by rf magnetron sputtering. The samples at different deposition pressure and Ar partial pressure were post annealed at 1000oC in oxygen. It is found that the preferred orientation of MgO thin films strongly depended on the total pressure and Ar partial pressure according to XRD analysis results. The orientation of Si substrate could also influence the orientation of MgO thin films. The post annealing process made MgO thin films turn out to be crystal and post annealing-process resulted in micro-cracks on the face of MgO thin films.
  • . 2010, 41(07): 4-0.
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    Abstract: The isoflavones 3a and 3b were synthesised and characterized by IR, 1H NMR, MS and elemental analysis. The UV and fluorescence spectra were measured. In different pH, compound 3a and 3b show different absorbance peak, the absorbance peak shifted regularly with the pH data increased. The structure of 3a and 3b show interesting change in different In pH condition. The fluorescent spectra showed that in different solvents, compound 3a and 3b show different fluorescent intensity.
  • ; ;;;
    . 2010, 41(07): 5-0.
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    (GDC/YSZ)12 oxygen ionic conductive multi-layers with different modulation ratio were synthesized on (0001) single crystal sapphire substrates using reactive magnetron sputtering method. The composition of the multi-layers, measured by microprobe technology, is 5.73:1 (Zr : Y ) and 4.12:1(Ce : Gd ) in molar ratio. The results of X-Ray Diffraction (XRD) and X-Ray Reflection (XRR) measurements indicated the super-lattice structures for samples with GDC/YSZ modulation ratio of 5:1,2:1 and 1:2. Atomic Force Microscopy (AFM) results showed that the multilayers exhibit surface morphologies of dense growth islands with smaller sizes and higher density as compared with GDC and YSZ single thin films. Measurement and analysis of the electrical properties indicated that the multilayer with rough interfaces had a higher conductivity, meanwhile, more GDC composition caused higher conductivities for the multilayers with superlattice structures.
  • Qi Yu Min;Chunxiang Cui;;
    . 2010, 41(07): 6-0.
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    The morphologies, microstructure and growth of the potassium hexatitanate whiskers was analyzed by XRD、SEM、TEM. The results showed that K2Ti6O13 whiskers reaction synthezed have higher superficial quality, being stylolitic in shape. Array of its interior atoms was very inerratic and crystal dislocation was not found. Side surface and terminal surface of whiskers have a transition layer of atoms staggered arrangement. The growth direction of whiskers is along their axial and radial. And the axial coarsening rate of whiskers is faster. The axial growth direction parallels to [010] orientation.
  • Zhenghou Zhu
    . 2010, 41(07): 7-0.
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    A small amount of La added to Fe73.5Cu1Nb3Si13.5B9 amorphous ribbons was successfully prepared by single-roller method, and the influence of test frequency, test temperature and annealing temperature on the piezomagnetic properties of La-doped ribbons is investigated. It is found that the sensitivity and the thermostability of the piezomagnetic properties of La-doped ribbons significantly enhance as compared with the pure ribbons at the same condition. The stress-impedance of the ribbons increases as soon as increasing the test frequency in the range of 1KHz~1MHz. The ΔZ of the ribbons dramatically increases with the increasing of stress in the range of 0~0.2MPa, while the trend of stable in the later range of 0.2~1.2MPa. When in the test temperature of 20~50℃, the ΔZ of the ribbons increases with the rising of test temperature. the temperature stability of the ribbons remarkably improves as soon as trace of La doping to ribbons, and its temperature coefficient (αT) changes from 1.3×10-3Ω/℃ to 2.68×10-4Ω/℃. The piezomagnetic properties of ribbons greatly enhances, while annealing treatment to ribbons.
  • . 2010, 41(07): 8-0.
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    Polyaniline (PANI) nanofibers were synthesized in the presence of triblock copolymer P123 (EO20PO70EO20). The morphology, composition, and optical properties of the resulting products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, and ultraviolet-visible absorption spectra. In addition, PANI was also immobilized on the surface of a glassy carbon electrode (GCE) to construct a biosensor. The obtained PANI-modified GCE showed high catalytic activity for the oxidation of ascorbic acid. The possible formation mechanism of the PANI nanofibers was also discussed.
  • ;;;
    . 2010, 41(07): 9-0.
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    BaCo0.7Fe0.3-xNbxO3-δ (x=0.08~0.14) were synthesized by solid state reaction. Niobium doping had significant effect on structural stability, chemical stability, microstructure, and oxygen permeability of the oxides. The higher formability and grain refining with the increase of niobium concentration would enhance the oxygen permeation of membrane. The oxygen permeation of BaCo0.7Fe0.2Nb0.1O3-δwith different sintering time confirmed that grain refining enhances the permeability of BaCo0.7Fe0.3-xNbxO3-δ membrane.
  • Zhenghou Zhu
    . 2010, 41(07): 10-0.
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    The effects of heat processing on electromagnetic shielding properties of composites based on Fe73.5Cu1Nb3Si13.5B9 amorphous powders/butyl rubber were investigated. The results show that the best electromagnetic shielding properties of composites have been obtained at 350℃ for 1h in the state of amorphous, the shielding properties can be further improved at 550℃ for 2h when powders have been partly crystallized and the value of ︱SE︱at 550℃ for 2h is 2 to 3dB higher than that of︱SE︱at 350℃ for 1h in the frequency range 1000~6000MHz; The shielding properties were also remarkably influenced by post-heat treatment of composites, the amplitude of shielding property increases most obviously after post-heat treatment for 6 h when the powders are in the form of amorphous. The value of ︱SE︱has been improved more than 3dB at 180℃ for 6h in contrast to the non-heat-treatment composites when the frequency is in the range of 1000 to 6000MHz.
  • Bo Zhang
    . 2010, 41(07): 11-0.
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    Using metal–organic chemical vapor deposition system, GaN films were grown on the patterned silicon-on-insulator (SOI) substrate by epitaxial lateral overgrowth. GaN films were characterized by the scanning electron microscopy (SEM), the Cross-section transmission electronmicroscopy (XTEM) and the Raman spectroscopy. It is shown that the residual stress and the threading dislocation density can be decreased in the ELO areas of GaN films.
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    . 2010, 41(07): 12-0.
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    A green-emitting phosphor Zn2Ca(PO4)2:Tb3+ was prepared by high temperature solid-state reaction. The XRD pattern indicated that the phosphor of Zn2Ca(PO4)2:Tb3+ synthesized under reducing atmosphere at high temperature was pure phase. The result showed that the main excitation peaks were located at 340~400nm and the emission peaks centering 490nm, 544nm, 584nm and 622nm were corresponding to 5D4→7FJ(J= 6, 5, 4, 3) transitions of Tb3+. The effect of the contents of Tb3+ ion in Zn2Ca(PO4)2 on the luminescent intensity was studied. The self-quenching mechanism of Tb3+ monitored at 544nm was analyzed. And the effect on intensity by adding the sensitizer Ce3+ was also investigated. The luminescence characteristics demonstrates that this green phosphor Zn2Ca(PO4)2:Tb3+ has a potential application for UVLED.
  • Ling Wang
    . 2010, 41(07): 13-0.
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    La0.5Ce0.5Ni5 alloy was prepared via the electrochemical deoxidation in a molten CaCl2 electrolyte at 850℃ by constant voltage electrolysis, with sintered pellets of a mixture of La2O3, CeO2 and NiO as cathode and high density carbon rod as anode. The the analytical results of XRD and SEM show that the sample sintered at 1050℃ can be deoxidized to La0.5Ce0.5Ni5 alloy when samples were electrolyzed at voltage of 3.1V for 12 h. XRD patterns of samples electrolyzed at voltage of 3.1V for different times show that the reduction mechanism is that firstly NiO was reduced to Ni,and then LaOCl and CeOCl were reduced to La and Ce on the surface of newly formed Ni and form La0.5Ce0.5Ni5 alloy. Whereas LaOCl and CeOCl came from La2O3 reaction with CaCl2 and CeO2 partially reduced.
  • Chen Xiao Qing ;;;
    . 2010, 41(07): 14-0.
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    Al-doped SiC films are deposied on silicon substrates by metal-organic chemical vapor deposition (MOCVD). The flow rate ratio between SiH4 and TMA, which determines the aluminium content in the SiC films, plays an important role in determining the conduction type of SiC films. XPS spectrum shows that aluminium atoms are institials in major and the SiC films are n-type when the aluminium content is less than 1.5% and that aluminium atoms substitute silicon atoms in major and the films are p-type when the aluminium content is between 1.5% and 3.0%, and the SiC films becomes high resitivity and the crystall quality becomes worse as the aluminum content exceeds 3%.
  • ;Kongjun Zhu;;;
    . 2010, 41(07): 15-0.
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    0.55Pb(Ni1/3Nb2/3)O3–0.45Pb(Zr0.3Ti0.7)O3 (0.55PNN-0.45PZT) piezoelectric ceramics are high-performance piezoelectric materials, which are widely used to fabricate the fibers with Pt core and other electronic devices. In order to improve the electrical properties of the piezoelectric ceramic fibers, the 0.55PNN-0.45PZT ceramics with high electrical properties were fabricated by the traditional sintering method in this study. The effects of sintering temperature on the phase structure, microstructure and electrical properties of material have been investigated. High electrical properties ceramic were fabricated by optimizing the sintering temperature. The highest piezoelectric properties were observed when the ceramics were sintered at 1200℃ and their values were ρ=8.12g/cm3, d33=850pC/N, kp=0.62, εr=7317, tanδ=0.033, and Qm=41.66.
  • Da-Li YAN;De-Jun Li
    . 2010, 41(07): 16-0.
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    The structure and Curie temperature of ErFe10.5-xCrxMo1.5 (x=0, 0.5, 1, 1.5, 2, 2.5, 3) compounds have been investigated by means of X-ray diffraction and magnetization measurements. The compounds all crystallize in the ThMn12-type structure. With increasing Cr content, the unit-cell volume and the lattice constant a and c decrease first, and then increase. This may result from the preferential occupation of Cr. Magnetization measurements show that the Curie temperature TC of ErFe10.5-xCrxMo1.5 compounds decrease monotonously with increasing x. This may be due to the comprehensive factors that the substitution of Cr for Fe weakens the Fe-Fe interaction and the preferential occupation of Cr in the ErFe10.5-xCrxMo1.5 compounds.
  • . 2010, 41(07): 17-0.
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    Thermal expandable microcapsules were prepared by suspension polymerization method with Toluene-p-sulfonyl hydrazide as core material and poly (AN-MMA-BA) as shell material. The effect of surfactant on size distribution and that of monomers composition on thermal expansion of the microcapsules obtained were discussed. The chemical structure, morphologies and property of microcapsules were characterized. FTIR spectra identified successful capsulation of Toluene-p-sulfonyl hydrazide(TSH) in poly(AN-MMA-BA) shell material. Well defined core-shell structure was clearly shown in the SEM image of the cross-section of microcapsule. Desirable thermal expansion property can be obtained with a shell monomers composition of 70%AN/20%MMA /10%BA. Waterborne wood coatings containing 2% of thermal expandable microcapsules exhibited an obvious thermal expansion after heat treatment. TG analysis suggested that thermal degradation of APU coating film containing microcapsules started at 210 °C, which was 20 °C higher than that of APU coating film without microcapsules, and terminated at 380 °C, revealing a slow thermal degradation between 250 to 320 °C. It was indicated from TGA determination that Thermal decomposition rate of the coatings film became slow, presenting thermal stability.
  • Yanghuan Zhang ;;;;
    . 2010, 41(07): 18-0.
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    In order to improve the hydriding and dehydriding kinetics of the Mg2Ni-type alloy, Ni in the alloy was partially substituted by element Co. The nanocrystalline/amorphous Mg20Ni10-xCox (x = 0, 1, 2, 3, 4) alloys were prepared by melt-spinning technology. The structures of the as-cast and spun alloys were analyzed. The hydriding and dehydriding kinetics of the alloys were measured. The influences of substituting Ni with Co and melt spinning on the hydriding and dehydriding kinetics of the alloys were investigated. The results show that no amorphous phase formed in the as-spun (x=0) alloy, but the as-spun (x=4) alloy shows nanocrystalline and amorphous structure, indicating that the substitution of Co for Ni enhances the glass forming ability of Mg2Ni-type alloy. The substitution of Co for Ni did not change the major phase of Mg2Ni in the alloy, but it led to secondary phase MgCo2 formed. The hydrogen absorption capacity of the alloys first increases and then decreases with rising Co content, but the hydrogen desorption capacity of the alloys monotonously grows with increasing Co content.
  • ma-tai DING ;;;;
    . 2010, 41(07): 19-0.
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    Due to their excellent fluidity and self-cross-linking, hyperbranched liquid polycarbosilanes (HBPCSs) have found applications as a matrix source for SiC matrix composites. Therefore, the HBPCSs have drawn great attention. This article reviews the development focused on synthesis, cross-linking, ceramization and applications of the HBPCSs. In addition, the expectations of developments of the HBPCSs in the future were given.
  • . 2010, 41(07): 20-0.
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    Nitric oxide (NO), with a variety of biological properties and functionalities such as anti-coagulant and anti-proliferation of cells, is an important signal molecule in the cardiovascular system. In this work, for improving the anti-platelet adhesion ability of the TiO2 film, a catalytic activity layer was built by grafting the cysteamine or cysteamine selenocysteine onto the TiO2 film. Firstly, the dodecyl phosphonic acid was self-assembled onto the TiO2 film surface with aim to gain the alkyl groups, The 4 - azido acid molecules was then bonded to the dodecyl phosphonic acid by photochemical methods for forming a functional layer with carboxyl groups. Furthermore, the cysteamine or cysteamine selenocysteine was chemically connected onto the above surface due to the carboxyl group activated by the EDC/NHS/MES solution system. The FTIR absorption spectroscopy (FTIR) and the X-ray photoelectron spectroscopy (XPS) results showed that, the molecule of cysteamine and cysteamine selenocysteine was successfully grafted to the TiO2 film surface, respectively. The in vitro catalytic experiment results confirmed that the modified layer possessed the catalytic activity. The platelet adhesion experiment disclosed that the modified TiO2 film surface could prohibit the adhesion behavior of platelets. This work successfully improved the biocompatibility of the TiO2 film, and provided a novel method for the bio-catalytic activation of the inorganic materials.
  • SONG Xue-ping ;
    . 2010, 41(07): 21-0.
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    Surface topography of ultrathin Au films with different thicknesses, prepared by direct current magnetron sputtering technique, was analyzed by atomic force microscopy. Power spectral density was used to calculate fractal dimension of the ultrathin Au films. The results show that as sputtering time increases, the fractal dimension of Au films decreases from 2.579 to 2.500 in high frequency region, and that of Au films increase from 2.607 to 2.819 in low frequency region. The surface topography of Au films has multi-scale feature. Multifractal spectra show that the spectrum width of Au films changes from 0.051 to 0.118, indicating that surface roughness of Au films increases with increasing sputtering time. The of samples are positive, suggesting that the number of highest peak sites greater than that of lowest valley sites.
  • yu Quanzhuang li
    . 2010, 41(07): 22-0.
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    Nano-sized GaOOH and GaOOH:Eu3+grains have been successfully synthesized by hydrothermal method by adding NaAc at 170℃. The as-synthesized product was characterized by X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and fluorescence spectrophotometer. From the experimental results, it was revealed that NaAc played an important role in the formation of the samples with different morphologies and sizes. The GaOOH obtained at 140℃ are cubic crystals and GaOOH obtained at 170℃ are nanoparticles of 5 nm. The growing mechanism of GaOOH with or without NaAc at different temperatures was discussed in the paper. Compare the GaOOH:Eu3+ obtained at different temperatures, the corresponding emission intensity of GaOOH:Eu3+ prepared at 170℃ was higher than that of 140℃. When the doping concentration is 10mol%, the sample has the highest emission intensity which is 4 times of the results that have been reported and concentration quenching was observed when the doping concentration reached 15mol%.
  • ;;
    . 2010, 41(07): 23-0.
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    A novel kind of thermoresponsive shape memory fiber was prepared by mixing the P(SA-co-AA) copolymers of stearyl acrylate (SA), and acrylic acid (AA), with PVA polyvinyl alcohol through chemically crosslinking after spinning and drawing. The molecular structure, thermomechanical properties and shape memory behaviors of mixed fibers with different drawing ratio were investigated. It was found that the rupture strength of fibers increased and the swelling ratio of them decreased with the increasing of drawing ratio. The crystal melting temperature increased and the module of fibers increased.The drawed P(SA-co-AA)/PVA fibers also showed a good shape memory effect, and the shape reversion ratio increased with the increasing drawing ratio.
  • . 2010, 41(07): 24-0.
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    Effects of the proportion of formaldehyde to urea, condensation polymerization temperature and time, condensation polymerization pH, as well as the addition of modifiers on free formaldehyde content of urea formaldehyde (UF) resin adhesive, which was prepared using urea and formaldehyde as the main materials , were studied. The optimal conditions to produce the adhesive with a free formaldehyde content of 0.25% were obtained on the premise of the bonding strength of the adhesive.
  • xia xiaohong
    . 2010, 41(07): 25-0.
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    High specific surface area activated carbons used for supercapacitors were prepared from bamboo char and petroleum coke by activation with KOH. The influences of the ratio of KOH to carbon on pore structure, adsorption behavior and capacity performance were investigated. Particular pore structure was showed in activated carbon when different carbon precurcor was used. Abundant micropores (<2 nm) were discovered in bamboo char-based AC, whereas a relative high mesoporosity was exhibited in petroleum coke based AC when at the same ratio of KOH to carbon. The KOH-activated bamboo char and petroleum coke carbons presented high BET surface area up to 2610.7 m2/g and 2597.9 m2/g , respectively. When used for the electrodes of supercapacitors, they exhibited excellent capacitance characteristics in 30 wt% H2SO4 aqueous electrolytes and showed high speci?c capacitances of 206 F/g and 213 F/g, respectively.
  • ;;
    . 2010, 41(07): 26-0.
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    Different amounts of Cu-doped TiO2 nanotube arrays were prepared by dipping method using anodized titania nanotube arrays as precursors. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD),X-ray photoelectron spectra (XPS) and photoluminescence spectra (PL) were used to characterize the samples. Aqueous solution of Cr6+ was used as target contamination in photoelectrocatalytic reactions to compare reductive effects of different amounts of Cu-doped TiO2 nanotube arrays. The results showed that morphology of titania nanotube arrays had no evident change before and after copper doping. The doped copper in the titania nanotube arrays was confirmed as Cu2+ .The reductive effect of Cu-doped titania nanotube arrays was improved after copper doping; and low-concentration Cu-doped TiO2 nanotube arrays was better than high-concentration Cu-doped ones.
  • Lian-Liang WANG
    . 2010, 41(07): 27-0.
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    LiFePO4/C particles whose partial appearance was three dimensional network structure was prepared by hydrothermal method with that acidified Li2CO3 as the lithium resource. Its highest specific capacity was 143.4 mAh/g and no capacity lost was found after 100 charge-discharge cycles at 0.5C. Li1-xFePO4 were prepared by chemically delithiated method. Li1-xFePO4 were characterized by XRD and EIS. Results show that, with the increasing extraction of Li+ from LiFePO4, XRD analysis of Li1-xFePO4 support the LiFePO4/FePO4 model. Surface resistance of cathode and anode increases at first and then decreases.
  • JIA Gui-xi
    . 2010, 41(07): 28-0.
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    Self-lubricating Cr/C composite coatings were deposited on GCr15 bearing steel balls,45# steel and single crystal silicon substrates by closed field unbalanced magnetron sputtering ion plating technique with same sputtering carbon current and different sputtering chromium current. Coatings microstructure was analyzed by the XRD, friction and wear behaviors, adhesion, hardness and toughness were tested, coatings wear scars were observed by the OM. Results indicate that coatings microstructrue are amorphous phase structrue, with chromium target current increased, and gradual transition to crystal phase structure . Compared to the uncoatings, coatings have excellent friction and wear performance and Payload capacity behaviors. At chromium current of 0.1A to 1.0A, coatings hardness gradually decreased and toughness gradually strengthened. The coatings of chromium current 0.1A and 0.3A have better self-lubricating properties, and the latter has the best comprehensively mechanical properties.
  • . 2010, 41(07): 29-0.
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    A series of p-N,N-dimethylaminobenzaldehyde thiosemicarbazone molecules has been synthesized and characterized by elemental analysis, 1H NMR,and MS . Their solid fluorescence was determined and studied with respect to their solid fluorescence properties and their crystal structures.The study show that with the poor packing of π-π interaction results in its monomer emission.
  • ;DU Gao Xiang;;
    . 2010, 41(07): 30-0.
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    The surface of superfine magnesium hydroxide was modified with Trimethoxy[3-(phenylamino)propyl]silane. The modification mechanism was analyzed by SEM, TGA-DSC and FT-IR. The results showed that the siloxane structure grafted onto the surface of magnesium hydroxide. The modification effect was evaluated by oil absorbing rate, sedimentation time and suspension viscosity of magnesium hydroxide in liquid paraffin. The optimal dosage of silane was 1.5 wt%. As a result, both of the dispersivity and lipophilicity of modified magnesium hydroxide improved remarkably.
  • . 2010, 41(07): 31-0.
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    New preparation method of aluminum foam was explored by accumulative roll-bonding with L2 pure aluminum as matrix metal and TiH2 powder as blister. The results show that the ARB cycle has significant effect on porosity and average pore size of aluminum foam, so porosity increases and average pore size reduces with ARB cycles increasing. TiH2 content and foaming temperature are major influencing factors for foaming driving forcing. Foaming driving forcing enhances with TiH2 content increasing and foaming temperature improving in the range of test temperature so that both porosity and average pore size increase after foaming. L2 pure aluminum of ARB six cycles containing 0.5wt.% TiH2 foams at 670℃ for 5min, through which aluminum foam with 61.4% porosity and 1.6mm average size is produced. Studies mentioned above indicate that accumulative roll-bonding is an effective preparation method of aluminum foam, which can prepare aluminum foam with pore uniformity and high porosity by parameter optimization process.
  • ;;
    . 2010, 41(07): 32-0.
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    ABSTRACT: In this paper, the effect of ZnSO4.7H2O, NaH2PO2.H2O, pH of the bath, temperature on deposition rate and deposition composition were investigated. The compositions were characterized by scanning electron microscopy, energy dispersive analysis and X-ray diffractometer. The best processing conditions are: 25g/L NiSO4.6H2O,8g/L ZnSO4.7H2O, 60g/L C6H5Na3O7?2H2O, 25g/L(NH4)2SO4?H2O , 30ml/L lactic acid, Ph=9.0, and the bath temperature is 85℃±1℃. The electroless plating Ni-Zn-P alloy is composed with amorphous and solid solution of nickel. The erosion behavior was tested with 0.05mM HCl. The results show that , mass loss of the deposition is increasing with corrosive medium flow rate increasing and erosion angle decreasing.
  • Hao Xiao Li;
    . 2010, 41(07): 33-0.
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    The novel porous semi-interpenetrating network (semi-IPN) membranes of Calcium Alginate (CA) - Poly (vinyl Alcohol) (PVA) were prepared by freeze-drying method. The surface structure of the porous membranes was characterized by SEM, and their water absorption ratio, retention ratio and swelling ratio were explored. Results showed that the membranes possessed interconnected pore structure and the average pore sizes were 40-200um. The membranes were sensitive to the normal saline,while their absorbency and retentiveness were relevant to the concentration of PVA. The membranes could reach swelling equilibrium in 10mins.?
  • bai yong mei
    . 2010, 41(07): 34-0.
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    Li0.99Y0.01FePO4/C composite material was synthesized by solid state method with phenolic resin as carbon source. The crystalline structure, morphology of particles, structure of surface and electrochemical performance were characterized by X-ray diffraction, scanning electron microscopy, high resolution transmission electron microscope and galvanostatic experiments. The results show that the Li0.99Y0.01FePO4/C material is pure olive-type phase, the composite particles after covering with carbon constitute a well conductive network, therefore its electrochemical performance is greatly improved. When the current density is 0.1C, the fist discharge capacity is 143.43 mAh/g and the charge-discharge efficiency is 90.54%, When the current density is 0.1C, the first discharge capacity is 101.17 mAh/g.
  • . 2010, 41(07): 35-0.
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    Abstract : The self- assemble behavior between the dendrimer PAMAM (1G) and the derivatives of Indolizine (CCA) were studied ,which realized the peripheral modifying for the dendrimer PAMAM, and also realized the transferring of CCA from oil phase to water phase. The fluorescent intensity and the UV absorbance of the PAMAM solution are all increased with the concentration of CCA obviously, all proved the self-assemble really happened.
  • ;
    . 2010, 41(07): 36-0.
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    The unmodified nano-SiO2 and organic modified nano-SiO2 (5wt% SiO2) which was treated with KH550, KH560, KH570 and KH8431 were used to prepare EVOH /SiO2 nano-composites, and the composites were blown to film later. Nano-SiO2 treated by different silane coupling agents were characterized and analyzed by FT-IR and TEM, and the structure of the composites was analyzed by SEM. The rheological behaviors, mechanical properties, barrier properties, thermal properties and transparency of the composites were characterized too. The results show that: chemical bonds were formed between nano-SiO2 and the four silane coupling agents, and the organic modified nano-SiO2 had a better dispersion and processability than unmodified nano-SiO2 in the EVOH. In contrast, nano-SiO2 treated with KH550 had the best dispersion and interaction force with EVOH. Compared to the composites prepared by unmodified nano-SiO2, the tensile strength and storage modulus of the composites prepared by organic modified nano-SiO2 increased by 17.2% and 136%, and the moisture permeance factor and oxygen permeability coefficient decreased by 11.2% and 9.5% respectively, and the light transmission rate was 74.9%, fog degree was 14.89%.
  • ;;
    . 2010, 41(07): 37-0.
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    Great difference in self-assembly has been found when linear diblock (SB), linear triblock [(SB)2] and four-arm star-shaped triblock [(SB)4] poly(styrene-block-butadiene) copolymers dissolved in selective solvent methyl ethyl ketone. Viscosity measurement and TEM observation show that, single-molecular aggregates formed with the inner polybutadiene blocks of (SB)4 self-assembled together while outer polystyrene blocks stretched out; open-style core-shell structures of (SB)2 were observed when the polymer concentration was below the critical concentration, while stable aggregates could be formed when concentration over the critical concentration; SB self-assembled into giant aggregates to form swelled colloidal particles.
  • Yuan Junjie ;
    . 2010, 41(07): 38-0.
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    Using sulfonic acid-functionalized hollow silica spheres (SHS) as templates and KNO3 as oxidant, the silica/MeFe2O4 hollow composite spheres was prepared by co-precipitation reaction. The results indicated that sulfonic acid groups on the SHS surface have strong adsorption capacity to the transition metal ions and MeFe2O4 nanoprticles. The MeFe2O4 nanoprticles were coated on the hollow silica shell. The crystal sizes of the MeFe2O4 nanoparticles on the SHS could be controlled under 15nm by adjusting proportion between Me2+ and Fe3+. The composite hollow spheres show soft magnetic properties. The saturation magnetization of silica/MeFe2O4 hollow composite spheres was 9.75emu/g when the total concentration of the metal ion was 0.10M.
  • DING Mei feng
    . 2010, 41(07): 39-0.
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    Abstract: Barium ferrite (BaFe12O19 ) thin films have been grown on (0006)-oriented sapphire substrates with MgO buffer by pulsed laser deposition(PLD). The effect of substrate temperature on microstructure and magnetic properties were studied. X-Ray Diffraction studies show that excellent C axis oriented BaM films on sapphire substrates were obtained. And the optimum conditions were found to be as follows: deposition rate 6Hz, pulse laser energy intensity 180mJ/pulse, MgO thickness 50 nm and growth temperature 750℃, Excellent C axis oriented BaM film was observed, The full width at half maximum (FWHM) of (0008) rocking curve is 0.289°of BaM film, indicating that the film is of a good quality. Scan electron micro-scope (SEM) analysis showed that thin BaM films have a few of hexangular grains when growth temperature reached 750℃. Vibrate sample magnetometer investigation showed that the perpendicular saturation magnetism and squareness (SQ=Mr/Ms) for the BaM/MgO/Al2O3 sample fabricated at 750℃ are 190 emu/cm3 and 0.82,respectively. Thus, the obtained BaM thin films with the high crystalline quality and good magnetic property in our work is helpful to study the fabrication of thick films and related devices.
  • Zhang Hui
    . 2010, 41(07): 40-0.
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    AZO thin films were prepared on PEN substrate by r.f. magnetron sputtering method at room temperature. The structural, optical and electrical properties of the films deposited under varied working pressure (0.05Pa~0.4Pa) were investigated. The results showed that films exhibited good c-axis preferred orientation. Increased working pressure reduced the intensity of (002) peak and grain size, roughened the film surface, and debased the electrical properties. Film transmittance in visible range changed little at higher working pressure, but the optical band gap was narrowed down. Compared with those on glass substrate, films on PEN exhibited higher figure of merit, with optimized resistivity of 1.11×10-3Ω?cm, carrier concentration of 4.14×1020cm-3, Hall mobility of 13.60 cm2 V-1s-1, and an absolute visible transmittance of 95.7%.
  • LIU Xiang Zhi;;;;;
    . 2010, 41(07): 41-0.
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    Abstract: Nano-alumina powders with different specific surface area were prepared by sol-gel method, ultrasonic-chemical precipitation method and reverse microemulsion method. The morphology, structure, specific surface area and pore volume of the nano-alumina powders were characterized and compared by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), X-ray diffraction (XRD) and specific surface area analyzer. The specific surface area of the nano-alumina powders is in the range of 200 m2/g to 600 m2/g (changing with different preparation methods) and the crystal structure is γ-Al2O3. The particle size is very uniform. The effects of different preparation methods and different drying methods on the characteristics of the product were studied. The results indicate that the nano-alumina powders with specific surface area higher than 500m2/g can be prepared by vacuum freeze-drying process combining with reverse microemulsion method.
  • ;Qi-An ZHU ;;;
    . 2010, 41(07): 42-0.
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    The precursor, BaO2?H2O2 were prepared from the reaction of BaCl2?2H2O and H2O2 in NH3?H2O aqueous solution under the ambient condition. BaTiO3 nanoparticles were produced by molten salt method using H2TiO3 and the as-prepared precursor BaO2?H2O2 as reactant, KNO3 and KOH as a flux. XRD, SEM, TEM, EDS and FT-IR techniques were used to characterize the structures, morphologies and compositions of the products. The results show that BaTiO3 nanoparticles with uniform size distribution and particle sizes of 25—50 nm, similar to spherical shape, can be obtained through calcining an mixture of the molten salt at 500—600℃ for 24h, and the structures of the as-obtained nanoparticles are of cubic phases. As the increases of reaction temperature, the cell parameters of BaTiO3 nanoparticles decrease, and the crystallite sizes increase. In addition, the formation mechanism of BaTiO3 nanoparticles prepared by molten salt method was also discussed.