25 February 2010, Volume 41 Issue 02
    

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    研究与开发
  • Preparation and Properties of Aliphatic Polyurethane/Hydroxyapatite composites by In Situ Polymerization
    ;;;;
    . 2010, 41(02): 1-0.
    Abstract ( ) Knowledge map Save
    In order to avoid toxic degradation products of aromatic polyurethanes in vivo, aliphatic polyurethanes with good biocompatibility and bioactive hydroxyapatite were selected to fabricate porous PU/HA scaffolds for tissue engineering by in situ polymerization. The morphology and properties of the scaffolds were characterized by SEM,IR and mechanical testing. The effects of the amount of blowing agent(water) and HA content on the pore structure and mechanical strength of scaffolds were investigated. The results indicate that when adding 1wt%-1.5wt% blowing agent into PU, the scaffolds possess interconnected porous structure with a pore size mainly ranging from 300μm to 800μm, and 50-200μm micropores existed on the pores’ walls, the porosity of the scaffolds is more than 80%. The compressive strength and modulus of the composite scaffolds show higher enhancement with increasing HA content. Considering comprehensively the reinforcing effect of the HA filler and the open porous structure for tissue engineering scaffold, in this system, the optimal addition of HA particles in polyurethane can be 40wt% and the optimal amount of blowing agent can be 1wt%.
  • Room-temperature ferromagnetism in Zn1-xCoxO DMSs prepared by rheological phase reaction method
    wang yong
    . 2010, 41(02): 2-0.
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    Abstract：Zn1-xCoxO（x=0.02,0.04, 0.06, 0.08）diluted magnetic semiconductors were synthesized by rheological phase reaction-precursor method. No secondary phase was observed with the sensitivity of XRD measurement. Electronic microscope photos and absorption spectra results indicated that Co2+ successfully incorporated into the wurtzite lattice at the Zn2+ sites. The measurement of magnetism was carried out by using a superconducting quantum interference device (SQUID), it reveals that the Zn0.96Co0.04O powder clearly exhibit room-temperature ferromagnetic behavior. The mechanism of this phenomenon is discussed with the BMPs theory.
  • Synthesis and photocatalytic property ofAg+/ FeVO4 Photocatalyst
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    . 2010, 41(02): 3-0.
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    ABSTRACT: Silver( Ag+) doped iron（III）vanadate( FeVO4) sanples were prepared by the liquid phase precipitation method. The obtained samples were characterized by XRD, SEM, BET, and XPS and their photocatalytic activity was studied by photocatalytic oxidation of methyl orange under energy-saving lamp irradiation. The XRD patterns indicated that Ag+/FeVO4 photocatalysts consist of triclinic phase and the lattice was distorted beacause of doping Ag. Doping with the appropriate Ag content can improve the photocatalytic activity of FeVO4. In the experimental conditions used, the optimal photocatalytic activity for all the prepared samples is reached when the Ag doping was 1 wt%. The decoloration rate of MO was more 20％ or so than that of pure FeVO4.
  • Feasibility of Ti Alloy Plating Ni Used in the air industry
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    . 2010, 41(02): 4-0.
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    The feasibility of Ti alloy Ti6Al4V plating Ni used in the air industry is searched in the paper, results show that the Ti alloy plating Ni not only owns high surface hardness, but also own excellent anti-wear, can be as the material of air craft: the combinative intensity between Ni plating coating and Ti alloy is 232Mpa, high enough to resist the impact of air environment, and fit to as the material of air craft; the hardness of Ni plating coating is 527 HV0.1, improve the seizure resistance and anti-scratching of Ti alloy, as it is used to be the material of air craft, Ti alloy can resist scratch well; on the condition of dry friction, the wear loss of Ni plating coating is only 1/47 of Ti alloy’s, when lubricating by seawater, the wear loss of Ni plating coating is only 1/42 of Ti alloy’s, so plate Ni on Ti alloy can improve the property of anti-sliding wear; the abrasive wear test shows that the wear loss of Ni plating coating is 5.4mg/1000circle, but the wear loss of Ti alloy is 28.9mg/1000circle, more serious than Ni plating coating, then plate Ni on Ti alloy can improve its property of anti-abrasive wear. To sum up, the plating coating of Ni is not only combine with Ti alloy tightly, but also improve the surface property of Ti alloy, tie in the high specific strength, excellent anti-erosion of Ti alloy, Ti alloy fits to be the materail of air craft.
  • SYNTHESIS AND CHARACTERIZATION OF STAR-SHAPED POLY(ε-CAPROLACTONE) WITH END GROUP FOLIC ACID
    ;;;Xianglin Luo
    . 2010, 41(02): 5-0.
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    Abstract Star-shaped poly(ε-caprolactone)s (StarPCLs) with six arms were successfully synthesized via ring-opening polymerization (ROP) of ε-caprolactone (CL) initiated by a dendrimer which was synthesized by TME and 2,2-bishydroxymethylepropanoic acid. Then by conjugating the end hydroxyl groups of StarPCLs with the carboxyl groups of folic acid, star-shaped poly(ε-caprolactone)s with folic acid (StarPCL-FAs) were obtained. Characterizations of these materials by 1H-NMR, FT-IR were carried out. The Results showed that the arm number of the StarPCLs was in accordance with the hydroxyl group number of the initiator and the conjugation of folic acid was successful. These polymers are expected to be used as drug carriers for targeted drug delivery.
  • The effects of heating rate on densification and microstructure of Y-α-sialon ceramics
    SHAN Ying Chun;
    . 2010, 41(02): 6-0.
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    The composition of yttrium-doped α-sialon was designed according to Y-Si-Al-O-N phase diagram, and the α-sialon with composition of Y0.4Si9.8Al2.2O1.0N15 was fabricated by hot pressing at 1900 ℃ for 30 min, then the effects of heating rate on the densification, phase composition and microstructure were investigated. It was found that single phase α-sialon ceramics were prepared in all the samples, and all the densification process curves show the same changing tendency for the sialon sintered by different heating rate, but they parallel move to high temperature zone with heating rate increasing , and the start and finish temperature of shrinkage and the peak value of shrinkage rate of the ceramics all increase with heating rate increasing. Higher heating rate contribute to increase nucleation density and inhibit elongated grain developing, and the size and aspect ratio of elongated grains decrease with heating rate increasing.
  • Preparation and Properties of Cd1-xZnxS (x=0.88) Polycrystalline Thin Films
    Wei Li
    . 2010, 41(02): 7-0.
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    In this paper, the polycrystalline Cd1-xZnxS thin films were prepared by the vacuum co-evaporation method and structural, optical, and electrical properties of Cd1-xZnxS（x=0.88）thin films were investigated. Cd1-xZnxS（0 ＜x ≤0.9）thin films were hexagonal structure and showed highly preferential orientation. The composition of Cd1-xZnxS thin films determined from Vegard law and quartz crystal oscillation method agrees with that determined from the X-ray fluorescence spectra. Optical absorption edge of optical transmittance for Cd1-xZnxS thin films exhibits a blue shift with the increase of the zinc content, which indicates that optical energy gap can be tuned between 2.44~3.78 eV. Finally, the values of dark conductivity for Cd1-xZnxS thin films at various temperatures were measured, and conductivity activation energies were calculated.
  • The influence of filled carbon black on the properties of conductive silicon rubber used in flexible tactile sensor
    ;huang yu;;;
    . 2010, 41(02): 8-0.
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    Carbon Black (CB) filled in insulating Silicon rubber to produce the conductive Silicon rubber with piezoresistive properties, which is common material to make flexible tactile sensors. Experiments had been conduct to research the percolation phenomenon of the three types of CB, piezoresistive properties of the Silicon rubber when the three types of filled CB are at the same content. The result exhibited that the Percolation thresholds are different; the Piezoresistive properties are different at the same content. Studied the piezoresistive properties of the same type of CB at different contents, discovered that the piezoresistive properties was best when the filler content was at percolation threshold. Scanning electron microscopy (SEM) was used to analysis the cross-section morphology of conductive Silicon rubber, the research showed that the conductive performances were related to the dispersion of CB filled in the matrix, which was related to structural characteristics of CB: the smaller the particle size, the greater the apparent density and specific surface area, in other words, higher structure CB would obtain better dispersion, lower percolation threshold and better piezoresistive characteristics.
  • STUDY ON THE PREPARATION OF SHAPED ACYIVE CARBON BY BITUMINOUS COAL AND ITS PERFORMANCE FOR CONCENTRATING METHANE FROM CH4/N2 BY PRESSURE SWING ADSOEPTION
    Min GU;
    . 2010, 41(02): 9-0.
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    Abstract：Shaped active carbon adsorbents using bituminous coal from Chonqing mine as raw material for concentrating methane from CH4/N2 mixtures were prepared by taking carbonization-activation-deposition process and the effect of the preparation conditions on the pressure swing adsorption (PSA) concentrating performance was studied. The micro-structure characterization of active carbon was investigated by low temperature liquid nitrogen adsorption method. Experimental results showed that the methane concentration had increased 20.0% at the vacuum stage of PSA process with five steps using the shaped active carbon prepared as absorbent. As for one of the shaped active carbon adsorbents which concentrating effect was 20%, its BET specific surface area was 580m2/g, total micropore volume was 0.14cm3/g and its pore diameter size distribution was mostly between 20? and 40?.
  • Electrochemical Properties of LiFe1-2xMnxMgxPO4/C cathode material as lithium ion batteries
    . 2010, 41(02): 10-0.
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    LiFe0.8Mn0.1Mg0.1PO4/C and LiFePO4/C were respectively prepared using MnCO3 and (MgCO3)4?Mg(OH)2?5H2O, glucose as doping starting materials by high-temperature solid state reaction under Ar atmosphere. The prepared composites were characterized by X-ray diffraction, scanning electron microscope and FT-IR spectroscopic, and electrochemical performance was investigated with constant current charge-discharge experiment. The results showed that LiFe0.8Mn0.1Mg0.1PO4/C preserved olivine structure with no impurity. Compared with LiFePO4/C, the electronic conductivity of LiFe0.8Mn0.1Mg0.1PO4/C has been improved. LiFe0.8Mn0.1Mg0.1PO4/C had a reversible capacity of 131mAh/g at 0.1C discharge rate, and showed good electrochemical properties.
  • Structure and the dependence of magnetic properties on temperature for rare earth ErCrO3 chromites
    SU Yu Ling;;;;
    . 2010, 41(02): 11-0.
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    The rare earth ErCrO3 chromites have been systemically studied by structural and magnetic measurement. The results indicate that the samples show the perovskite-type ErCrO3 orthorhombic structure with space group Pbnm. The magnetic properties shown that ErCrO3 possess significant weak ferromagnetism below 133K. At TSR≈20K, ErCrO3 undergoes a spin reorientation from Г4(Ax,Fx,Cz) toГ1(Ax,Gy,Cz) orГ1(0) where the weak ferromagnetic moment disappears. And in the region of higher temperature T＞133K, the reciprocal of magnetic susceptibility of ErCrO3 chromites behaves linearly indicating a typical Curie–Weiss behavior fitted. The effective magnetic moment μeff=10.57μB and asymptotic paramagnetic Curie temperature Tcw=-30K, which suggests the predominance of antiferromagnetic interactions in ErCrO3 chromites. The current magnetization can be interpreted from the interaction between Cr3+-Cr3+，Cr3+-Er3+，Er3+-Er3+.
  • Microstructure and electrochromic mechanism of WO3 film
    Yang Hai-Gang ;;;;
    . 2010, 41(02): 12-0.
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    Tungsten oxide films were deposited on ITO coated glass substrates by reactive DC magnetron sputtering. The electrochromic (EC) properties of the films were studied with different target-substrates distance in the deposition process. The WO3 films were characterized with x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The electrochromic properties and mechanism were discussed by means of spectrophotometry. It indicates that the samples are amorphous and have more pores that are beneficial for Li+ to inject and eject from the film. The original-state films are composed of tungsten and oxygen, and tungsten ions are W6+. After electrochemical reactions, the main component becomes LixWO3 in which tungsten ions normally exhibit both W6+ and W5+. The films exhibited cathodic electrochromism. The coloration and bleaching of the WO3 film is associated with insertion and deinsertion of Li+ ions and electrons in the films.
  • Synthesis and electrochemical properties of LiNi0.8Co0.2O2 prepared by the eutectic molten-salt method
    . 2010, 41(02): 13-0.
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    he cathode material LiNi0.8Co0.2O2 for lithium-ion battery is prepared using the eutectic molten salt 0.434LiNO3-0.266LiOH?H2O-0.3CH3COOLi?2H2O, which is in well molting state at 80-90℃. The well-layered α-NaFeO2 structure and regular morphology are confirmed by X-ray diffraction (XRD) and scanning electronmicroscopy (SEM). Electrochemical studies indicate the first discharge of this sample is 174.1 mAh/g at a 0.2C between 2.8-4.3V and the discharge capacity retention of 95% after 20 cycles.
  • PREPARATION OF HYDROXYAPTITE/CHITOSAN COMPOSITE SCAFFOLDS VIA IN-SITU HYDRATION
    LI Hong;;
    . 2010, 41(02): 14-0.
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    Abstract Hydroxyapatite(HAP)/chitosan(CS) composite is a biocompatible and bioactive biocomposite. In order to enhance the properties of the composite, a novel homogenous HAP/CS composite scaffold was developed via lyophilization and in situ hydration. The morphologies, components, mechanical strength, bioactivity and biocompatibility of the composite scaffolds were investigated. The HAP particles with relatively homogenous distribution in the pore-wall surface of the scaffold were obtained while the scaffold remained sponge structure after hydration treatment. X-ray diffraction (XRD) and Fourier-Transformed Infrared spectroscopy (FTIR) confirmed the phase purity of the formed HAP crystals. The compressive strength of the scaffold showed much higher than those of the scaffold blended and the CS-only scaffold. The results suggest that the homogenous composite scaffolds with better strength can be prepared via the in situ hydration process, which may serve as a good scaffold for bone tissue engineering.
    • 论文
  • N,N-DIMETHYLFORMAMIDE-MEDIATED SYNTHESIS OF COPPER SULFIDE POWDER AND CHARACTERIZATION
    caiwen
    . 2010, 41(02): 15-0.
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    copper sulfide powders were successfully synthesized by solvothermal method with CuCl2?2H2O as the copper source, N, N-dimethylformamide as the reaction medium, L-cysteine, thiourea, thioacetamide as the sulfur source respectively at 130°C for 8h. The crystallinity, phase structure, morphology, composition and optical property of the as-prepared samples were investigated by X-ray diffraction(XRD),X-ray photo-electron spectroscopy(XPS),field-emission scanning electron microscopy(FESEM), Transmission electron microscope(TEM) and UV-vis absorption spectroscopy respectively. The results showed that structure and morphology of the products were significantly influenced by the sulfur source. The CuS product synthesized in dimethylformamide(DMF) with L-cysteine as the sulfur source was amorphous stacked by numerous nanoparticles disorderly, but those synthesized with thiourea and thioacetamide as the sulfur source respectively were microspheres composed of large numbers of nanorods. The morphology and form of CuS synthesized with different sulfur sources were discussed. And the possible growth mechanism of products with different morphologies was expatiated based on the experimental results.
    • 研究与开发
  • Effect of Ce Dopant on the Crystal Transformation of TiO2
    ZHU Zhen Feng
    . 2010, 41(02): 16-0.
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    With Ti(OBu)4 and Ce(NO3)3?6H2O as raw material, the pure and Ce doped TiO2 powder were prepared by a sol-gel method. The effect of dopping amount on the crystal transformation of TiO2 was studied. The results showed that the doped Ce hindered the process of phase transition of TiO2 particles from anatase to rutile, and propagated the temperature ranges of anatase. The crystallites growed larger with the increasing of the calcination temperature, and the crystal size became smaller with the the doping increased. TiO2 particles were well dispersed in the state of anatase, with no agglomerates observed.
  • Research of Formation Mechanism and Process of Zinc Phosphate Coating on AZ91D Magnesium Alloy
    HU WEI;;
    . 2010, 41(02): 17-0.
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    Abstract: The formation mechanism, coating structure and growing process of zinc phosphate coating on AZ91D magnesium alloy were studied by means of scanning electron microscopy(SEM), X-ray diffraction(XRD), open circuit potential(OCP) . The results show that the growing process of zinc phosphate coating on AZ91D magnesium alloy forming in the phosphating bath process is divided into five stages: the initial nucleation stage(1-5 s), the rapid dissolution stage(5 s-1 min), the rapid growth stage(1-2 min), steady-state growth stage(2-10 min) and the deposition-dissolution equilibrium stage(after 10 min). The hopeite phosphate coating on AZ91D magnesium alloy formed in the zinc phosphating bath by batches. The first batch of hopeite nucleus grow into grain gradually, continuous nucleation of new generation occurred simultaneity. The coverage of phosphate grain increased gradually on the alloy surface, the boundary of grain growing closed, and the phosphating process is end until the entire surface is completely covered. With the growth of nucleation and its epitaxial, the phosphate coating formed of on AZ91D magnesium alloy, which is not occured in the metal matrix of the grain boundary with priority.
    • 论文
  • Review on influence factors of surface plasmon resonance for nobel metal nanoparticles
    liuhuixin
    . 2010, 41(02): 18-0.
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    Noble metal nanoparticles could be used to optical energy transport, near field scanning optical microscopy, surface enhanced spectroscopy, chemical and biological sensors because of its tuneable plasmon resonant frequency. This article reviews systematically the influences of particle size, distribution, shape, volume fraction, constitute and structure on the plasmon resonant absorption, which are helpful to deeply understand the physical origin of the plasmon resonant absorption and to tune plasmon resonant frequency.
    • 研究与开发
  • Synthesis and characterization of poly(ethyleneglyeol) modified Poly(lactide)
    . 2010, 41(02): 19-0.
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    Abstract: The biodegradable material poly(D,L-lactic acid)-polyethylene glycol(PLEG) was synthesized with stannous octanoate as catalyst via directly melt polycondensation of D,L–racemic lactic acid (D,L–LA) as monomer with PEG–400,600,800,1000 and 2000 at molar ratio n(PEG)/n(D,L–LA)＝1/600. The copolymerization reaction was performed at temperature of 170℃, ω(Sn(Oct)2) of 0.8%, and pressure of 0.096 MPa for 8 hours. The PLEGs were characterized by viscosity-average molecular weight, FT–IR, XRD and contact angle testing. The results demonstrate that the contact angle of PLEG–800 was 63°and the maximum Mη of PLEG–800 can reach 48997. Better hydrophilicity and crystallinity can be reached in case of PEG is chosen as 800,compared with poly(D,L-lactic acid).
  • Synthesis and Electrochemical Properties of Li4Ti5O12 Nano-crystalline by Nonaqueous Sol-gel Method
    Jin Wang;;;
    . 2010, 41(02): 20-0.
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    Nano-sized Li4Ti5O12 powders with high dispersivity were prepared by a novel sol-gel route using lauric acid as surfactant. The crystal structure, microstructure and the electrochemical properties of the samples were characterized by XRD, SEM, TG-DSC and galvanostatically charge-discharge experiments. The effects of molar ratio of Li to Ti, the content of surfactant and the calcining temperature on the phase structure, the microstructure and the electrochemical properties were studied to optimize process. The results demonstrated that the crystallization, microstructure and electrochemical properties were influenced significantly by the content of the surfactant. Li4Ti5O12 powders calcined at 800℃ for 10 h comprised of crystallites with the particle size in the range 100～300nm revealing high dispersivity almost without any agglomerates, exhibiting an excellent electrochemical performance. Its discharge capacity at 1C and 2C rates can reach 163.3 and 132.3mAh/g, respectively. After 50 cycles, fairly stable cycling performance was achieved without obvious capacity fade.
  • Magnetic property and microstructure characterization of Fe3O4 nano-magnetic ferrofluid
    ;
    . 2010, 41(02): 21-0.
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    This paper introduced the preparation, performance and applications of Fe3O4 nano-magnetic ferrofluid, principally observed the characterization of microstructure by Atomic Force Microscope (AFM), and measured the particle size and morphology of nano-magnetic ferrofluid. The magnetic property was analyzed from the microstructure characterization, the analysis results show that: The size of Fe3O4 nano-particle is about 5.00 nm, the magnetic property is closely related to the chain microstructure and influenced by nano-particles distribution in Fe3O4 magnetic ferrofluid.
  • Preparation and photoactivity of zinc phthalocyanine grafted thermosensitive hydrogel
    ;;;;
    . 2010, 41(02): 22-0.
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    A novel polymer catalyst (GE-ZnPc) was prepared by immobilizing highly reactive zinc phthalocyanine onto Poly(N-isopropylacrylamide) hydrogel. The thermosensitive property of GE-ZnPc was studied by differential scanning calorimetry, and the volume phase transition temperature was 34.28 °C. The photocatalytic activity of GE-ZnPc for the oxidation of α-naphthol was determined by ultra performance liquid chromatography. The result showed that GE-ZnPc exhibited a high photocatalytic activity under the visible light irradiation. Furthermore, the result of gas chromatography-mass spectrometry analysis indicated that the main oxidative product of α-naphthol was phthalic acid. In addition, GE-ZnPc was stable and remained efficient in six test cycles.
  • PREPARATION AND ADSORPTION PROPERTIES OF SODIUM ALGINATE/MULTIWALLED CARBON NANOTUBES COMPLEX GEL BEADS
    ;dan xie
    . 2010, 41(02): 23-0.
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    Abstract This study deals with the development of a clean and safe process for water pollution remediation. To follow an ‘ecoconception’ approach, gel beads containing multil-walled carbon nanotubes (MWNTs) are prepared with a biopolymer extracted from algae, sodium alginate (SA). The use of renewable bioresources of low cost and those disposable in large amount allows the development of a product with a low impact on the environment. In this study, MWNTs are individually dispersed in aqueous solution using SA through noncovalent method, and then the SA-Ca and SA-MWNTs-Ca gel beads are prepared in CaCl2 solution. Their adsorption capacity is investigated by measuring the removal of methyl orange (MO) of different charges from aqueous solutions. The remove rate of the beads has been compared with that of non-encapsulated MWNTs. The results showed that the remove rate of MO from aqueous solutions using SA-Ca gel beads is very low, and it could be improved sharply with the increasing of the content of MWNTs in SA/MWNTs-Ca gel beads. The amount of SA/MWNTs-Ca gel beads has significant effect on adsorption of MO. Adsorption efficiency in different pH values are also studied, which showed that it has better adsorption at low pH value due to the specific surface area increasing of SA/MWNTs-Ca gel beads in acidic environment.
  • Structure and Surface Morphology of nano-crystalline CdZnTe films by Vacuum deposition method
    ZHOU Hao
    . 2010, 41(02): 24-0.
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    Nano-crystalline CdZnTe films were grown on ITO glass by Vacuum deposition method. The thickness，composition, surface morphology and structure were studied by the Step profiler，the X-ray Photoelectron Spectroscopy (EDS), X-ray diffraction (XRD), Atomic force microscope (AFM). The results showed that the films possess a preferable growth surface of (111). The films are rich in amorphous Te at the beginning of the growth, but tend to the stechiometric composition of zinc blend structure of CdZnTe crystal. The surface roughness (Ra) of the films was 2-5 nano-meters. With the increase of the time, the individual grains tend to form continues multi-grain layer. For the deposition time of 15min、30min and 45min, the thickness of the film as measured to be 100nm、300nm and 400nm, and the average size of the gain are 43.15nm、30.81nm and 71.94nm respectively.
  • Syngas Production from coke oven gas by using an oxygen-permeable membrane reactor
    ;;
    . 2010, 41(02): 25-0.
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    Syngas from coke oven gas was investigated in an oxygen-permeable membrane BaCo0.7Fe0.2Nb0.1O3-δ (BCFNO) reactor. It was found that the membrane itself has poor catalytic activity methane. After the catalyst was packed on the membrane surface, both methane conversion and oxygen permeation flux were greatly improved by the synergetic effect between the membrane and catalyst, at 875 ℃, 87.0% of methane conversion, 78.3% of H2 selectivity, 105.6% of CO selectivity and as high as 15.8 ml/cm2/min of oxygen permeation flux were obtained. The react pathway of CH4 in the coke oven gas in the membrane reactor is as follows: firstly, H2 in the coke oven gas reacts with the O2, and generate H2O, then CH4 reforms with the H2O to produce H2 and CO. The membrane reactor exhibited not only good activity but also chemical stability resistance to hydrogen-enriched COG atmosphere.
  • Effect of the Ammonia Flow Rate on the the Growth and Characterization of GaN Nanowires
    ;;;;;
    . 2010, 41(02): 26-0.
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    Ga2O3/Co films were deposited on the Si substrates through magnetron sputtering technique. Then the films were annealed at 950℃ for 15min at different ammonia flow rate. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transformed infrared (FTIR) spectroscopy, high resolution transmission microscopy (HRTEM) and photoluminescence (PL). The results show that the ammonia flow rate had a great effect on the the growth and characterization of GaN nanowires. The growth mechanism is briefly discussed.
  • Studies on non-stoichiometry CaCu3Ti4O12 giant dielectric constant ceramics
    . 2010, 41(02): 27-0.
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    Abstract：Non-stoichiometry CaCu3Ti4O12（CCTO）ceramics are prepared by the conventional solid-state reaction method .Relative dielectric constant of CCTO ceramics attain 4×105（1KHz）if the atoms mol ratio of Ca、Cu、Ti elements are 1.08：3.00：4.44. It is one magnitude higher than stoichiometry CCTO ceramics . Microstructures and crystalline structures and component analyzing are examined by scanning electronic microscopy (SEM)、 x-ray diffraction (XRD) and energy dispersive x-ray spectroscopy(EDX), respectively. The giant dielectric constant mechanism of CCTO ceramics is discussed.
  • INFLUENCE OF ANNEALING ON STRUCTURE AND MAGNETIC PROPERTIES OF AMORPHOUS NICKEL-PHOSPHORUS ULTRAFINE POWDERS
    ;
    . 2010, 41(02): 28-0.
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    Abstract: Ultrafine nickel-phosphorus powders were prepared by pulse discharge in NiSO4 solution containing the reducing agent of NaH2PO2. The nickel-phosphorus powders were annealed at temperatures ranging from 200℃ to 450℃ and then analyzed by TEM、FESEM and XRD. The magnetic properties of the products was characterized by VSM. The results showed that the ultrafine nickel-phosphorus powders were amorphous. The grains with diameters between 300nm and 500nm were linked tightly in the form of chain-liked structures. Excellent soft magnetic performance was obtained after annealing at a temperature of 250℃ or 280℃, and the coercivity of nickel-phosphorus powders was reduced to 0.437G after annealing at the temperature of 250℃.
  • Study of Preparation and Field Emission Properties of ZnO nanomaterial
    Zhi-xian LIN;;;
    . 2010, 41(02): 29-0.
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    A variety of morphologies and dimension of ZnO nanomaterial was synthesized using hydrothermal methods. The structure and morphologies of ZnO products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The impact of the growth of ZnO material factors was analyzed and the mechanism of growth was discussed too. The characteristics of field emission for a variety of morphologies ZnO array were studied. The experimental results show that field emission performance of nano-tube ZnO was the best in all of various structure of ZnO nanomaterial. The maximum current density reached 0.2 mA/cm2 and its turn-on field was 2.5 V/μm. The results provide a feasible method for improving field emission properties of Zno nanomaterial.
  • Preparation and photocatalytic degradation properties of ZnO nanopodwers with different morphologies
    ;;;;Tianyou Peng
    . 2010, 41(02): 30-0.
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    ZnO nanopowders with different morphologies were prepared by using Zn(NO3)2?6H2O and NH4HCO3 as raw materials through a direct precipitation method. The effect of reaction terminal pH values and post-treatment of precipitation on the crystal phase, morphology, particle size distribution and aggregation of the obtained ZnO nanopowders were investigated in detail. The results show that the network-like and granular ZnO nanoparticles can be controllably prepared by adjusting the reaction conditions especially the terminal pH values. Moreover, the samples were utilized for the photodegradation of Rhodamine B in an aqueous suspension. The obtained network-like ZnO nanoparticles show excellent photocatalytic activity in comparison with the granular ZnO nanoparticles, and the photocatalytic activities of the network-like and granular ZnO nanoparticles are better obviously than that of the commercial available photocatalyst P25.
  • Studies on the Synthesize Iron Oxide from Ferric Citrate under Different Atmosphere
    . 2010, 41(02): 31-0.
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    Abstract: Iron Oxides were prepared by heat-treating ferric citrate under rich-oxide and non-oxide atmosphere. The pyrogenations of ferric citrate at different atmospheres were characterized by the technique of TG. The relation between the reaction temperature ＆ reaction time of pyrolyze ferric citrate and the composition, structure of iron oxide were studied by XRD. The results show that the pyrolytic products under air atmosphere are Fe3O4, the transformation of α-Fe2O3 from Fe3O4 is enhanced with increasing reaction temperature or prolonging reaction time; while, the pyrolytic products under non-oxide atmosphere are Fe3O4 and amorphous carbon, the redox reaction between Fe3O4 and amorphous carbon is promoted by increasing reaction temperature or prolonging reaction time.
  • The inhibitory effect on glioblastoma cells viability by nano-HA coatings and HA/CTS coatings
    ;;; ;
    . 2010, 41(02): 32-0.
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    In current study, nano-hydroxyapatite coatings (nHA), nano-hydroxyapatite and micro-hydroxyapatite/chitosan complex films (nHA/CTS, mHA/CTS) were electrodeposited on the titanium substrate. The physical and chemical characteristics of the coatings were profiled using X-Ray diffraction (XRD), SEM and FTIR determination. After co-cultured with human glioblastoma multiforme cell line U87(U87), the inhibitory effects of three kinds of surface layers on U87 cells viability were compared by MTT method and observation of the U87 cell morphology incubated on the coatings under SEM. The results showed that, among the 3 kinds of coatings, nHA coatings is more effective on inhibiting the proliferation of the U87 cells, and exhibits a potent anti-glioma capability in vitro.
  • Effects of Vanadium Carbide Nanopowders on Preparation of Ultrafine WC-based Cemented Carbides
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    . 2010, 41(02): 33-0.
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    Effects of vanadium carbide nanopowders (V8C7) on the phase compositions, microstructures and properties of ultrafine WC-based cemented carbides were investigated under Spark Plasma Sintering (SPS) conditions. The results show that ultrafine WC-based cemented carbides mainly consists of WC and Co3C phases, and the diffraction peaks of WC shift towards small angle compared with unsintered material. Vanadium carbide nanopowders can effectively inhibit the WC grain growth in ultrafine WC-based cemented carbides, and the inhibition action increases with increasing specific surface area of V8C7 nanopowders. The majority of the grain sizes WC are less than 0.5μm when ultrafine WC-based cemented carbide was added to V8C7 nanopowders with the specific surface area of 63.36m2/g. Vanadium carbide nanopowders have important effects on the properties of ultrafine WC-based cemented carbides, which increase with increasing specific surface area. Ultrafine WC-based cemented carbide has higher properties (Relative Density 99.5%, HRA 93.2 and KIC 12.5 MPa?m1/2) when it is added to V8C7 nanopowders with the specific surface area of 63.36m2/g.
  • Catalytic activity of electrodeposited amorphous Ni–Fe-P coating for hydrogen evolution reaction
    Li-Jun SONG;
    . 2010, 41(02): 35-0.
    Abstract ( ) Knowledge map Save
    Abstract: The different amorphous Ni-Fe-P coatings have been prepared with direct current plating technology through changing the current density. Catalytic activity of those electrodes prepared for hydrogen evolution reaction (HER) was compared with the steady-state polarization technique. Results indicated that Ni-Fe-P coating prepared at current density of 200A/m2 shows much better catalytic activity. Surface morphology and elemental composition of the coatings were investigated by scanning electron microscopy (SEM) and energy dispersive X-ray diffraction microanalysis (EDX). Crystal structure of coatings was determined by X-ray diffraction (XRD) analysis. Studies showed P content of amorphous Ni-Fe-P coating was responsible for catalytic activity. The maximum catalytic activity of HER for the Ni-Fe-P coating could be obtained at Fe content of maximum18.63 % and P content of minimum 13.14 %.
  • THE EFFECT OF THE SODIUM CONTENT ON THE HYDROTHERMAL TRANSFORMATION OF TITANATE NANOTUBES TO PREPARED TiO2 NANOMATERIALS
    xu yuan mei;;
    . 2010, 41(02): 36-0.
    Abstract ( ) Knowledge map Save
    Single-crystalline TiO2 nanomaterials were synthesized by hydrothermal method and characterized by XRD, TEM, and HRTEM. The effects of the sodium content of titanate nanotubes on the phase composition, morphology and size of the obtained TiO2 nanomaterials were investigated. At pH of 1, single-crystalline anatase nanoparticles with rhombic shape were obtained by hydrothermal transformation of titanate nanotubes with sodium content of 7.34%, whereas single-crystalline anatase nanoparticles in great majority and rutile nanorods in little minority were obtained by hydrothermal transformation of titanate nanotubes without sodium; At pH of 4, single-crystalline anatase nanorods with large aspect ratio were obtained by hydrothermal transformation of titanate nanotubes with sodium content of 7.34%, length of 300-500 nm, width of about 60 nm, whereas short anatase nanorods with size of 20×60nm were prepared by hydrothermal transformation of titanate nanotubes without sodium. The possible mechanism was presented on the effect of sodium.
  • Photocatalytic Effect of Zn/ZnO Nano-composite
    ;
    . 2010, 41(02): 37-0.
    Abstract ( ) Knowledge map Save
    Zn nano-particles were prepared by a dry roller vibration milling at room temperature, and Zn/ZnO nano-composite was manufactured by hydrolyzing Zn nano-particles. The Zn/ZnO nano-composite exhibited much better photo-catalytic performance under the sun and ultraviolet light irradiation. TEM and XRD analysis showed that Zn particles size was 10~20nm after 11 hour milling, and the solid product of the hydrolysis had a blended morphology of nano-rods and nano-flakes. UV-Vis spectra indicated that the absorption strength of the Zn/ZnO nano-composite much more exceeds that of the ZnO nano-particles in visible light zone, and particle size reduction causes the exciton peak blue shift, then nano-particles perform much better than bulk materials in the degradation process.
  • Performance Evaluation on Activated Carbon Fiber Anode in Electrochemical Oxidation process
    ;Shuixia CHEN
    . 2010, 41(02): 38-0.
    Abstract ( ) Knowledge map Save
    In this paper, the electrochemical oxidation process was performed using an activated carbon fiber (ACF) felt as an anode under constant current in Na2SO4 solution. After electrolyzing different times, ACFs were taken out and washed with distilled water and dried for 12h in vacuum at 110℃. After cooling to room temperature in desiccator, ACFs were weighed and analyzed by means of FT-IR spectroscopy and nitrogen adsorption method. At the same time, the contrast experiment was carried out using a graphite flake as an anode. The results showed that the amount of oxygen-containing groups on the ACF surface is increased in the process of electrochemical oxidation and ACF anode has better oxidation resistance performance and higher oxygen evolution potential compared with graphite anode. So, ACF is more appropriate to be the anode than graphite flake in the electrochemical oxidation process of refractory organics.
  • Preparation and characteristics of Cu/AAO composite
    zou xiao ;yang xiu chun;;;
    . 2010, 41(02): 39-0.
    Abstract ( ) Knowledge map Save
    Ordered porous anodic aluminum oxide (AAO) template with an ultrathin barrier and an Al substrate was successfully prepared by a method of step-by-step voltage decrement. Cu/AAO composite was prepared by electrodepositing Cu in the above-prepared AAO template by a cyclic voltammetry method. The morphology, composite and structure of Cu/AAO composite were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The results indicate that the Cu nanowires have a face centered cubic single crystalline structure, the filling degree of Cu nanowires in the AAO template is high and the diameter of the nanowire is about 70nm with a length up to 30μm.
  • SYNTHESIS AND CHARACTERIZATION OF ZnS:Cr NANOCRYSTALS by CO-PRECIPITATION
    . 2010, 41(02): 40-0.
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    ZnS and ZnS:Cr nanocrystals were synthesized by chemical co-precipitation method. Sodium lauryl benzenesulfate and sodium-hexametaphosphate were used as a dispersant. The crystalline, microscopy and luminescent properties of ZnS:Cr nanocrystals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectra. The results show that ZnS:Cr nanocrystals have cubic zinc blende crystal structure, and the size of these spheroidal particles is about 3 nm. At room temperature, the luminescence properties are investigated with PL spectra. In PL spectra, the emission peaks of ZnS:Cr at about 420nm and 440nm, which may be attributed to sulfur vacancy. The emission peak at 495 nm of ZnS:Cr be assigned to the emitting of surface states or centers of radiation. Fourier transform infrared red (FT-IR) spectroscopy results provide evidence of the presence of sodium-hexametaphosphate and TAA.
  • Preparation of nano TiO2 film modified with phosphatotungstic acid and photocatalytic performance
    . 2010, 41(02): 41-0.
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    The nano TiO2 film modified with phosphatotungstic acid （PW12/TiO2）was prepared by sol-gel method using tetrabutyl titanate (TBOT) as a precursor and acetic acid as solvent, and was characterized by FTIR,UV-Vis,XRD,BET and SEM. The result indicates that the TiO2 nanoparticles has the anatase structure and high specific surface. Phosphatotungstic acid still keeps Keggin structure in TiO2 ,and inhibites the growth of crystal grain. The photocatalysis degradation of p-chlorophnol with PW12/TiO2 film was investigated to study the catalytic activities of the film. The result indicated that photocatalysis reaction accorded to L-H mechanism with PW12/TiO2 film(the ratio of phosphatotungstic acid and titania was 0.02:1,calcinated at 240℃), First-order reaction rate constant was 0.016 min-1.There produced obvious synergy between PW12 and TiO2 in photocatalysis reaction.
  • Study on preparation and catalytic performance of transition metals nitrides over carbon nanotube
    . 2010, 41(02): 42-0.
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    Sevral transition metals nitrides over carbon nanotube were synthesized through impreganation methods and temperature-programmed reaction in N2-H2 mixture gases. The surface composition and reaction performance were investigated by XRD, BET, H2-TPR techniques . The results show that the CoNX/CNTs exhibited higher surface area and optimum catalytic activity for ammonia decomposition. The BET surface area of CoNX/CNTs could be up to 151.85m2?g-1. The ammonia conversion was 80.3% at 650℃, and complete decomposition of ammonia was observed at 850℃.
  • Synthesis of submicron long-lasting phosphor SrAl2O4:Eu,Dy by Hydrothermal-homogeneous precipitation method
    Li Yi Dong;;;
    . 2010, 41(02): 43-0.
    Abstract ( ) Knowledge map Save
    green long-lasting phosphors SrAl2O4:Eu2+,Dy3+ were synthesized by Hydrothermal-homogeneous precipitation method. X-ray diffraction, emission scanning electron microscopy, photoluminescence, as well as thermo-stimulated luimnescence were utilized to characterize the long-lasting phosphors. XRD analysis indicated the obtained SrAl2O4:Eu2+,Dy3+ annealed at 1000℃ for 4 hours were monoclinic crystal phase. With the temperature increasing, their crystallinity would also enhanced. The obtained phosphors consist of well dispersed submicron spherical particles with a narrow size distribution of 200-500nm，and these phosphor particles show Blue-purple emission corresponding to 5d-4f (513nm) of Eu2+ under the excitation of ultraviolet (360nm).
  • Study on the preparation and properties of Novel Poly (γ-benzyl-L-glutamate)-co-Poly (ethylene glycol)
    . 2010, 41(02): 44-0.
    Abstract ( ) Knowledge map Save
    Abstract: In order to improve the low biodegradation rate and the poor hydrophility of allyl-terminated poly (γ-benzyl-L-glutamate) (A-PBLG), dimethylacrylate poly (ethylene glycol) (DMA-PEG) with good hydrophility and antithrombogenicity was introduced to A-PBLG through in situ photo-crosslinking and the copolymer of A-PBLG and DMA-PEG (PBLG-PEG) was obtained. The structure of PBLG-PEG was characterized by Raman and XRD and its water absorbency, in vitro biocompatibility and antithrombogenicity were also studied at the same time. The results indicated that the hydrophility and biodegradation performances of PBLG-PEG were improved because PEG was hydrophilic and crystalline degree of PBLG in PBLG-PEG decreased. The results of blood platelet adhesion and hemolysis experiments showed that PBLG-PEG had better antithrombogenicity than A-PBLG.
  • Study on the gas sensitivity of PEDOT nanoparticles based on reversed micelle method
    . 2010, 41(02): 45-0.
    Abstract ( ) Knowledge map Save
    Based on a new type of conducting polymer poly (3, 4-ethylenedioxythiophene) (PEDOT), this paper focused on the preparation and gas sensitivity of PEDOT nanostructure with reversed micelle method. PEDOT nanoparticles were characterzed to gas sensitivity by different methods, such as ultraviolet/visible (UV-Vis) spectroscopy, X-ray photoelectron spectroscopy (XPS) and so on. The latest investigation of gas sensitivity of PEDOT nanoparticles to HCl gas was carried out, and it has been found that the response time of PEDOT nanoparticles deposited QCM to 20 ppm HCl gas was about 20 S and well reproducible sensitivity of QCM device was achieved. Furthermore, the nanoparticles exhibited well detecting ability to lower gas concentration (5 ppm) than conventional one.
  • Preparation and Characterization of photocatalyst with Porous shell and magnetic core structure
    li yu
    . 2010, 41(02): 46-0.
    Abstract ( ) Knowledge map Save
    Magnetic separable TiO2/SiO2/NiFe2O4 particles were synthesized by using P123 as direction agent and TBOT as the source of titanium dioxide. The samples were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The results showed that the coating composite are sphere and has an even distribution, and the average size was about 40 nm in diameter. The prepared samples have potential applications for cleaning polluted water with the help of magnetic separation. The photocatalytic activity of the composite particles was investigated for degradation of nitrobenzene by UV illumination. Experimental results show that the nitrobenzene pollutant can be completely degraded within 240 min, which showed it has excellent photo-catalytic property.
  • Measurement and analysis of mechanical properties of UV-LIGA Ni thin film
    ;;;;;
    . 2010, 41(02): 47-0.
    Abstract ( ) Knowledge map Save
    Electrodeposited Ni fabricated by LIGA or UV-LIGA, particularly suitable for micro-devices as a structural material. Mechanical properties of materials play an important role in micro-devices design, simulation and the actual use. In this paper, by the use of conventional mechanical testing machine and self-built micro-tensile platform, through a method of uniaxial tensile test, we measured mechanical properties of the UV-LIGA Ni thin films deposited with a current density of 20mA/cm2. The results of three test methods showed a consistent change - and Young's modulus dramatically reduced while strength significantly increased, indicating that UV-LIGA Ni has significantly different mechanical properties comparing with bulk Ni. Through X-ray diffraction spectrum analysis (XRD), we measured the preferred orientation and grain size of the specimen, by field emission scanning electron microscope (SEM), we observed the surface morphology and tensile fracture surface of the specimen, and preliminarily analyzed the causes of change in mechanical properties of UV-LIGA Ni. The test results provide an important frame of reference for the design and simulation of the micro-devices.
  • Preparation and Study of Spectra Characteristics of Expandable Graphite
    ;;;;;;
    . 2010, 41(02): 48-0.
    Abstract ( ) Knowledge map Save
    In this work, the expandable graphite (EG) with high expanding volume has been successfully prepared by chemical oxidation method using graphite powders (≤30 μm) as raw materials, H2SO4 and KMnO4 as oxidant, and H3PO4 as assisted intercalation agent. The micro-structure, morphology, spectral properties and thermal stability of the obtained products are characterized by XRD, Raman, SEM, EDS, FT-IR and TG?DTA. The experimental results show that the optimum volume ratio of H2SO4 and H3PO4 is 2 : 1, while the swelling volume at 400 ℃ gets to 102 mL.g-1. The elements such as P, S and Mn have been found in the layers of EG, therefore, there could be H3PO4, H2SO4, and dihydric phosphate & sulphate containing Mn in the layers of EG. It is also demonstrated that the initial expanding temperature of EG is about 160 ℃ through TG–DTA curves. The ordered structure of graphite hasn’t been absolutely destroyed after it is oxidized and intercalated, and part of EG sill has a good thermal stability under air atmosphere. In addition, the possible mechanism of EG formation and expansion has been discussed.
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