25 February 2011, Volume 42 Issue 02
    

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  • Hydrophilization of polymeric UF/MF membranes: from PEGylation to ionization
    ZHAO Yi Fan
    . 2011, 42(02): 1-0.
    Abstract ( ) Knowledge map Save
    For most polymeric ultrafiltration (UF) and microfiltration (MF) and membranes, the hydrophobic character of membrane materials fails to provide good antifouling ability and biocompatibility, and thus their applications are limited to some extent. An effective solution for this problem is improving the surface hydrophilicity of the membranes by surface modification. In the previous reports, PEGylation is the main way to perform surface modification. In recent years, ionization has being playing more and more important role in hydrophilization of membrane material. In this paper, the previous work on membrane hydrophilization in our groups is reviewed. PEGylation and ionization for UF and MF membranes are introduced in detail. Ionization is thought to be a new and dominating trend in future researches.
  • Progress in SrMoO4-based Materials with Scheelite Structure
    . 2011, 42(02): 2-0.
    Abstract ( ) Knowledge map Save
    SrMoO4-based materials with scheelite structure have wide applications in optical emissions, and optical detections and modulations. In the present paper, combined with the research results in the authors’ group and the research developments worldwide, the research progresses of SrMoO4-based materials were reviewed; the research status of SrMoO4-based solid-solution materials at present was discussed; the new development trend of SrMoO4-based materials was analyzed; and the future development for the SrMoO4-based material with scheelite structure was forecasted.
    • 研究与开发
  • The study of PLGA nanoparticle surface modified with chitosan as Protein Drug Carriers
    . 2011, 42(02): 3-0.
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    Abstract：The purpose of this research was to develop polylactic-co-glycolic acid nanoparticles (PLGA NP) surface modified with chitosan (CS). PLGA NP were prepared by a solvent evaporation technique. The PLGA NP surface was modified with CS by two strategies (adsorption and covalent binding, ADCS NP, CBCS NP). The change of Zeta potential, encapsulation efficiency, drug loading and in vitro release of nanoparticles were investigated using bovine serum albumin (BSA) as a model drug. PLGA NP of (228.1±20.4) nm in diameter characterized by the laser light scattering technique, scanning electron microscopy (SEM) are spherical and its drug encapsulation efficiency is (84.1±3.4)%. Zeta potential of PLGA NP was measured to be negative -(23.31±3.15)mV. The positive zeta potential of modified nanoparticles reveals the presence of CS on the surface of the modified nanoparticles. X-ray photoelectron spectroscopy (XPS) shows the N 1s (atomic orbital 1s of nitrogen) region of the surface of the modified nanoparticles, corresponding to the primary amide of CS. In vitro drug release demonstrated that the release ratios of BSA from three kinds nanoparticles followed the order of VCBCS NP> VADCS NP> VPLGA NP.. The conformation of BSA from the CBCS NP was altered (CD data) with the reductions of α-helices, and with increases of β-sheet for free BSA. The conformations of the BSA from PLGA NP and ADCS NP did not underwent significant changes. ADCS NP showed a potential as a good carrier for the pepteids drugs.
  • Preparation and Characterization of Hollow Hydroxyapatite submicrospheres/ Chitosan Injectable hydrogels
    LI
    . 2011, 42(02): 4-0.
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    Hollow hyroxyapatite(HAP) submicrospheres were prepared by a W/O/W multiple emulsion method, HAP/Chitosan hydrogels were developed by filling hollow HAP submicrospheres with chitosan/glycerol-phosphate(CS/GP) solutions, and chitosan hydrogels were also prepared. The composition and morphology of the products were analyzed by XRD、TEM、FT-IR and SEM, gel formation time, stability and compressive strength of the two hydrogels were measured. The results showed hollow HAP submicrospheres with diameter of approximately 300nm were obtained; the HAP/CS solution was neutralized to physiological pH and retained stable at room temperature while allowing gel formation upon heating 37℃. Both of the gels had open-cellular pore structure, and the Gel2 with increased porosity exhibited better compression performance than Gel1. The hollow HAP submicrospheres/CS injectable hydrogels have potential applications for the development of new tissue repairing materials.
  • Synthesis and Fluorescence Properties of a novel triphenylamine dendrimer
    Ying QIAN
    . 2011, 42(02): 5-0.
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    A novel triphenylamine dendrimer, 1, 2, 4, 5-tetra-{4-{N,N-Bis{4-{4-[5-(4-tert-butylphenyl) -1,3,4-oxadiazol-2-yl]-styryl}phenyl}amino} styryl} benzene(TPAB-OXA), were synthesized through Wittig-Horner reactions. The structure were characterized by IR, NMR and melting points. The maximum absorption peak in dichloromethane was at 420 nm for TPAB-OXA. The maximum emission wavelengths was at 504 nm for TPAB-OXA in dichloromethane. The fluorescence lifetime for TPAB-OXA were 1.41 ns with fluorescence quantum yields of 0.65. The relationship of Stoke’s shift with solvent polarity was discussed.
  • Experimental study of directed band gaps of 2D phononic crystal consisting of steel cylinders in water with square lattice
    ;Huanyu Zhao ;
    . 2011, 42(02): 6-0.
    Abstract ( ) Knowledge map Save
    Based on the ultrasonic immersion transmission technique, the directed band gaps of two-dimensional (2D) phononic crystal consists of a square array of steel cylinders in water were measured experimentally along the Γ-X and Γ-M directions of first irreducible Brillouin zone. The relations of layers and first band gaps stability can be analyzed in detail. This is better advantage of design for finite-sized 2D phononic crystal or acoustic devices. An excellent agreement between the frequency range of overlapping transmission spectra of acoustic waves and complete band gap of 2D phononic crystal for theoretical predict with plane wave expansion method is observe.
  • Influence of Concrete Constituents on Autogenous Shrinkage and Interior Relative Humidity of Concrete at Same Compressive Strengths
    HE Zhi Hai
    . 2011, 42(02): 7-0.
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    The influence law and mechanism as well as the relationships of polyvinyl alcohol (PVA) fiber, shrinkage reducing admixture (SRA) and the combined addition of fly ash and slag on autogenous shrinkage and interior relative humidity of concrete with 7 days same compressive strengths at early ages were studied by the self-made test device. The results indicate that PVA fiber, SRA and the combined addition of fly ash and slag significantly reduce autogenous shrinkage of concrete, the best effect with SRA; the development speed of autogenous shrinkage is very fast before 72 hours (3 days), more than 80% of the 672 hours (28 days) value, but the development speed of autogenous shrinkage of concrete with SRA is relatively slow, showing some lag effect; interior relative humidity of concrete at early ages has undergone the initial vapor saturated stage and the subsequent reduction stage, the concrete with SRA showing a strong moisturizing capacity; autogenous shrinkage of concrete also shows 2 distinct stages, corresponding with interior relative humidity, both showing significant linear correlation; the measured autogenous shrinkage of the vapor saturated stage mainly is chemical shrinkage and small amount of settlement shrinkage, depending on the moisturizing capacity of PVA fiber, SRA and mineral admixtures on concrete and autogenous shrinkage of the reduction stage mainly is self-desiccation shrinkage, depending on the hydration degree and rate of cementitious materials.
  • Electromagnetic properties and microwave absorbing characteristics of carbonyl iron/Si-epoxy matrix composites
    ;Fa-shen Li;;
    . 2011, 42(02): 8-0.
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  • Study on the thermoelectric properties of FeNi29Co18MnSi alloy
    . 2011, 42(02): 9-0.
    Abstract ( ) Knowledge map Save
    Abstract:This paper investigates the thermoelectric properties of FeNi29Co18MnSi alloy，It analyses the EMF of Ni-Co alloy and Ni-Fe alloy and the effect of content（Mn、Si）、cold working on EMF properties of alloy.
  • Electroless Nickel Plating on Diamond/Cu Composite Material for Electronic Packaging
    ;
    . 2011, 42(02): 10-0.
    Abstract ( ) Knowledge map Save
    Abstract：The electroless nickel plating was used to improve the weldability of diamond/Cu composite.Before the electroless nickel plating, the pretreatment was applied to the surface of the composite by means of sensitization with SnCl2 solution and subsequent activation with PdCl2 solution.The influence of pH value and temperature on plating rate were studied.The SEM、EDX、XRD and scratching method were used to examined the coating. The results show that a uniform ,compact and tight-bonded Ni-P coating could be plated on the surface of diamond/Cu composite.The coating is microcrystal, pertaining to medium phosphorous coating.
  • Synthesis and electronic transport research of Mn substituted NaxCoO2 ploycrystalline
    ;Yan guo wen
    . 2011, 42(02): 11-0.
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    The NaxCoO2(x=0.5+?,0.7)and Na0.5+?Co0.95Mn0.05O2 polycrystals are of γ-phase with highly preferential c-orientation, which were prepared by solid-state reaction; Mn-doping hinders the grain growth. The curves of resistivity vs temperature showed that NaxCoO2 present metallic behavior, the Na0.5+?Co0.95Mn0.05O2 present insulating behavior. We considered that the electrons of the 3d bands substituted by Mn4+ are less than the electrons of Co3.5+, which reduces the carriers in overlap band e`g+a1g of t2g orbital and increases the resistivity. In addition, the highest orbital level of Mn4+ t2g electrons occupied is lower than that of Co3.5+ t2g electrons does, which results in energy gap of electrons jumping, reduces the jumping probability and increases the resistivity. The grain boundary scattering also increases the resistivty.
  • CNT Promoted Preparation and Catalytic Properties of CuCo-based Catalysts for High-alcohol Synthesis
    ;
    . 2011, 42(02): 12-0.
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    CuCo-based catalysts for high-alcohol synthesis from syngas have been prepared by ultrasound assisted reverse coprecipitation. The influence mechanism of carbon nanotubes on the structure, adsorption property and catalytic imformance were investigated in the present work. The XRD results showed that CNT modification was favorable to the formation of Cu-Co spinel structure and increase active sites for alcohol synthesis. Temperature-programmed experiments analysis indicated that after the addition of CNT, the reducibility was improved, the capabilities of adsorption-activation of CO on the catalyst surface and carbon-chain growth were enhanced significantly. The CNT modified catalyst exhibits higher catalytic activity, alcohol yield and selectivity to C2+OH.
  • The Study of Silicon Carbide Ceramic Membrane used in oil-water separation
    ; ;;;;
    . 2011, 42(02): 13-0.
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    Under the conditions of temperature of 20 ℃ and transmembrane pressure (△TMP) of 0.2 MPa, a silicon carbide ceramic membrane with a pore size of 0.1 μm was introduced to treat oil wastewater with the dead end filtration method in conjunction with a periodical backwash technique. The membrane was found to exhibit high flux, and the quality of the permeate can meet the standards of the recommended “SY/T5329 - 94 of Injection Water Quality for Detrital Rock Oil Reservoirs and Analyzing Methods” of China. Especially, the membrane is easy to be cleaned, and membrane flux recovery can reach 100 %.
  • Effect of the treatment by different oxidation system on Multiwalled Carbon Nanotubes
    ;;
    . 2011, 42(02): 15-0.
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    Multiwalled Carbon nanotubes (MWCNTs) were functionalized with three kinds of oxidation system (H2SO4/H2O2, H2SO4/K2Cr2O7, H2SO4/HNO3), respectively. The samples were characterized by Fourier Transform Infrared spectroscopy (FT-IR), Raman spectroscopy, transmission electron microscopy (TEM), thermogravimetry analysis (TGA) and Zeta potential measurement analyzer. The results show that the tubular structures of MWCNTs are not distinctly destroyed. In addition, carboxylic groups (-COOH) are induced onto the surface of MWCNTs, the corresponding amounts of carboxyl are determined as 0.95%, 6.08% and 9.2% by acid-base titration according to the above sequence of oxidation system. Oxidized samples are dispersed in deionized water uniformly and stably.
  • Low Temperature Hydrothermal Synthesis and Performances of Nanotube Patterned Barium Titanates Thin films
    . 2011, 42(02): 16-0.
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    Nanotube patterned barium titanate thin films were prepared via hydrothermal method using titania nanotube arrays as a template. It was discussed that hydrothermal temperature, reaction time, the concentration of alkali effected on morphology of the samples. Crystal and micro-morphology were observed by x-ray diffraction and scanning electron microscope; thermal properties and dielectric behaviors of materials were characterized by thermogravimetry and differential scanning calorimeter and broadband dielectric spectrometer. The results demonstrated that single-phase structure of nanotube patterned barium titanate thin films could be obtained with the temperature as low as 100oC after reacting 6h. The longer of reaction time and the higher temperature were helpful to promote the dielectric constant of the samples. Diffusion rates of Ba2+ ions insert into the template was restrained while the growth rates of particles located at the surface of nanotubes were enhanced with the addition of mineralizer KOH. The phenomena of structural transition and phase transition for nanotube patterned barium titanate thin films present at the temperature of 700oC～1100oC and 1280oC, respectively.
  • Cordierite support fabricated from bimodal cordierite powder
    ;;
    . 2011, 42(02): 17-0.
    Abstract ( ) Knowledge map Save
    Cordierite powder with different diameters 1.5 μm and 25 μm were ball-mill mixed in a certain proportion, in which appropriate binder and pore-forming agent were added. After kneading、aging、extrusion molding and drying, green bodies were sintered by temperature-programming to certain temperature and held for 2h . It is shown that support body with 20 wt% fine powder and sintered at 1400℃ has much better comprehensive functions: water flux is 10.1m3.m-2.h-1 and the bursting strength is 2.21 MPa. After dipping in 5 wt% NaOH solution for 36 h at 100℃, the support body still has a bursting strength up to 1.85 MPa. This shows that the alkaline resistance property of cordierite support body is excellent and can be used under alkali conditions in industry.
  • Photoinduced Relaxation effect in YBCO superconducting thin film
    ;
    . 2011, 42(02): 18-0.
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    The superconducting thin film YBCO has been prepared on single crystal substrate LaAlO3 using TFA-MOD method. The XRD method is used to characterize the construction of superconducting thin film YBCO and we get the best technology of deposition. The photoinduced properties of the film in different temperature and laser power have been studied. The YBCO film obviously has the relaxation phenomenon related with electronic system under the laser irradiation. This proves that the superconducting state of the YBCO film is attributed to the power of laser.
  • Investigation of energy transfer and upconversion luminescence in Er3+/Ho3+-codoped GeS2-In2S3-CsI glasses
    ;;;;;
    . 2011, 42(02): 19-0.
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    A serials of chalcohalide glasses based on the composition 80GeS2-10In2S3-10CsI doped with the different Er3+/Ho3+ ions ratio were synthesized by melt-quenching technique. The state stability, Raman spectra, absorption spectra, upconversion emission spectra of glass samples were measured.Three intense upconversion luminescence emissions are observed at around 526,549,and 660nm, which correspond to Er3+: 2H11/2→4I15/2, Er3+: 4S3/2→4I15/2+Ho3+: 5S2(5F4) →5I8 , and Er3+: 4F9/2→4I15/2+ Ho3+: 5F5→5I8 transitions, respectively. In 0.6 mol%Er2S3/xHo2S3 codoped glasses , increase of Ho2S3 had positive effect up to the upconversion fluorescences. The upconversion emissions reach the maximum values when Ho2S3 is 0.6 mol%, and the intensities of the green and red light emissions were 4.2 and 10 times stronger than those un-doped Ho2S3, respectively. The possibie upconversion mechanisms and energy transfer between Er3+ and Ho3+ were also estimated and evaluated. All the three emissions are based on two photon absorption processes.
  • Research on tunable metamaterial absorber
    . 2011, 42(02): 20-0.
    Abstract ( ) Knowledge map Save
    Abstract：We present a simple design of electromagnetic metamaterial absorber, which is composed of periodic array of electric ring resonator (ERR) and short wires backed by a FR4 printed circuit board. This structure can provide electric and magnetic resonances in the same frequency range. By use of the numerical simulation method, we computed the S parameters, and figured out the absorbance in 8-12 GHz range. A single unit cell layer demonstrates an absorption peak greater than 98.7％ at 8.92 GHz. By adjusting the length and width of the ERR split, or the electromagnetic parameters of the substrate, the resonance frequency and the absorption band will change. By use of the effective circuit description of the structure, we can explain the electromagnetic absorption mechanism.
  • Study of the structure and soft magnetic properties of RE La-doped Fe-based amorphous strips
    xu xue jiao;
    . 2011, 42(02): 21-0.
    Abstract ( ) Knowledge map Save
    Fe-based amorphous strips are mainly used in the electrics and sensors fields. This paper discusses the structure and soft magnetic properties of La-doped Fe-based amorphous strips when the content of La is different. The results show that with the increasing of the weight ratios of La, the temperature of the precipitation of phase Fe-Si in the Fe73.5Cu1Nb3Si13.5B9 amorphous strips decreases, while the temperature of the precipitation of phase Fe-B increases; on one hand, the amorphous thermal stability goes down, on the other hand, phase Fe3Si can precipitate from the Fe73.5Cu1Nb3Si13.5B9 amorphous strips . After the La-doped Fe-based amorphous strips are annealed, when the weight ratio of La increase ,the testing frequency f between 50Hz and 1KHz, the Ls values decrease which means that the based mental exhibited excellent low-frequency characteristics, while when the testing frequency are 1KHz ~500KHz, the Ls values significantly increase. La can improve high-frequency properties of the amorphous strip. The comprehensively soft magnetic properties of amorphous strips with the weight ratios of La 0.7wt% are the best
  • Preparation of Mesoporous Nano-Alumina with Large Pore Volume and high specific surface area by pH swing precipitation - Azeotropic Distillation method
    ;;;
    . 2011, 42(02): 22-0.
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    Precursors of objective γ-Al2O3 were prepared from Al2(SO4)3 and NH4OH by pH swing precipitation method combined with azeotropic distillation. The γ-Al2O3 powders were obtained from the precursor after calcination at 550 ℃ and were characterized by means of XRD, BET, SEM and HRTEM. The morphology of γ-Al2O3 powders obtained from pH swing precipitation method is irregular. The specific surface area, average pore size, pore volume of γ-Al2O3 powders are biggest when reaction temperature is 80℃ and pH swing times is 3 without aging time. The fibrous nano mesoporous γ-Al2O3 powders obtained from pH swing precipitation method combined with azeotropic distillation are uniform in particle size distribution with large pore volume, large average pore size and high specific surface area. The average pore size is 16.04 nm; pore volume is 1.31 cm3/g; specific surface area is 327 m2/g, average particle width is 5 nm and average particle length is 40-60 nm.
  • Investigation of structure and optical property of Cup-like ZnO microcrystal prepared by a hydrothermal route
    LUO Ying Min
    . 2011, 42(02): 23-0.
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    Cup-like ZnO microcrystal were prepared by hydrothermal method with Zn(CH3COO)2?2H2O as source reactant. The X-ray diffraction spectra show that the typical wurtzite hexagonal structure was obtained. The single cup like ZnO crystals and the symmetric cup like ZnO crystals combined with each other were investigated by SEM photos. The morphology of ZnO crystals were mainly determined by the hydrothermal time, and the formation mechanism of cup like ZnO crystals were elucidated from the view of nucleation and growth based on the evolution of ZnO crystal with hydrothermal time. The effect of hydrothermal time modification on the optical property of ZnO crystals were investigated by room photoluminescence (PL) spectra.
  • Performances characteristics of dye-sensitized solar cells based on counter electrodes with different Pt concentration
    HUANG guang sheng ;
    . 2011, 42(02): 24-0.
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    Pt concentration have significant impact for the property of platinized counter electrode and the performance of the dye-sensitized solar cell (DSSC)，especially when illuminate the cell through the counter electrode(CE).In this research,DSSCs were based on CEs with Pt films of different concentration, the effects of the concentration of Pt film on impedence,light harvest when illuminate the cell through the CE were investigated. The result showed that 10mmol / L was the best Pt concentration illuminated through the CE, in a certain concentration range, open circuit voltage and energy conversion efficiencies at first increased and then decreased with the increase in the Pt concentration,at the same time short-circuit current decreased.
  • Preparation and Capacitive performances of activated carbon/MnO2 Composite Electrode Materials
    Li-Zhen WangZHANG Yong;;
    . 2011, 42(02): 25-0.
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    An activated carbon (AC)/MnO2 composite electrode material (MAC) was prepared by vacuum impregnation and chemical precipitation methods. The as prepared MAC was characterized by means of SEM, EDS and XRD and its electrochemical performance was investigated by cyclic voltammetry, A.C. Impedance and Galvanostatic Charge/Discharge tests. Test results showed that AC particles were coated with γ-MnO2. Under a current density of 200 mA/g, the specific capacity of the composite reached 417 F/g at first cycle, and declined to 337 F/g after 100 cycles, which was 116 % higher than AC. The composite also showed specific capacitances 231F/g at a higher current density of 200 mA/g, which is 99% higher than AC, exhibiting a better rate performance.
  • Agglomeration of aqueous ferrofluid subjected to the magnetic field by 3-D Dissipative Particle Dynamics simulation
    ;;;
    . 2011, 42(02): 26-0.
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    Based on the coarse graining model of ferrofluid, Dissipative Particle Dynamics simulations are performed in three-dimensional space to investigate the morphological characters and the distribution of agglomeration. Interaction parameters of components in ferrofluid are calculated by Flory-Huggins solution theory. The long-range interactions of magnetic nanoparticles are solved by Ewald summation method. The simulation results show that no ordering microstructure is observed in ferrofluid when there is no magnetic field. The length and the diameter of chain-like agglomeration increase with strengthening the magnetic field. More chain-like agglomeration formats with higher concentration of magnetic nanoparticles and the length added as the concentration and the diameter of nanoparticles increase.
  • Study on the preparation and anti-crossion performance of Ni-P/n-CeO2 composite coatings Study on the preparation and anti-crossion performance of Ni-P/n-CeO2 composite coatings Study on the preparation and anti-crossion performance of Ni-P/n-CeO2 composite coatings Study on the preparation and anti-crossion performance of Ni-P/n-CeO2 composite coatings of Ni-P/n-CeO2 composite coatings Study on the preparation and anti-crossion performance of Ni-P/n-CeO2 composite coatings Study on the preparation and anti-crossion performance of Ni-P/n-CeO2 composite coatings Study on the preparation and anti-crossion performance of Ni-P/n-CeO2 composite coatings of Ni-P/n-CeO2 composite coating
    zhou xiao wei
    . 2011, 42(02): 27-0.
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    Abstract: Electroless Ni-P/n-CeO2 composite coatings were preparated under the traditional watt acidic plating solution condition,and its anti-corrosion properties were studied and compared.Ni-P/CeO2 composite coatings were co-deposited on A3 steel substrate surface. The results show that the Optimal quantity of CeO2 additive should retain 15~20 g?L-1.Rare earth particles absorb on matrix surface and produce lots of nano-scale nucleus of crystal , refined grain. Only this, nano-CeO2 particle can get dispersed sufficiently and effectively. Rare-earth CeO2 increase the P content（wt（P）≥12%）. Rare earth particles n-CeO2 produced at micropore and other defects, decrease activity of impurities, refine the crystal boundary,which due to rare-earth CeO2 nano-particle addictive co-deposite with Ni,P. Corrosion test manifests that rare earth additive CeO2 makes porosity lower, the corrosion morphology of coatings has change from corrosive pitting to be general corrosion, the anti-corrosion property and passivity improve in Ni-P/CeO2 coatings. Electric polarization curves are determined by constant potential rectifier has used to study anti-corrosion resistance, the results show that potential ennoblement and corrosion current drop 1 order of magnitude. The polarization curves slightly move to positive direction and decrease corrosion current density. According to the electrochemistry theory, the corrosion property is improved.Besides, the paper also studys the effect upon heating about microstructure, anti-corrosion resistance and so on. It finds that Ni3P precipitation and Ni crystallization take place at 450℃ 2h heat treatment. In addition, Ni-P/CeO2 coatings have sintered phase of NiCe2O4 spinels, precipitated phase CeO2 is priority produced at micropore and other defects. So, Ni-P/CeO2 composite coatings can get diffused sufficiently and effectively, increase grain density ,microhardness can reach 1000HV .
  • The effect of temperature on the interface reaction and connectivity between Ag-Cu alloy braze and ceramic oxygen-permeable membrane
    LIU Jiao
    . 2011, 42(02): 28-0.
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    The sessile drop wetting experiment and joint strength test was conducted to study the Ag-3.3mol% Cu air brazing BaCo0.7Fe0.2Nb0.1O3-δ(BCFNO) mixed-conducting membranes for oxygen. The results indicate that the filler has good wetting property to the substrate; With the temperature increasing the wetting angle decreases and the joining strength increases. Controlling the brazing temperature over the monotectic reaction temperature within a certain range, the CuO-rich liquid reacting with BCFNO playing the role of pre-wetting and forming a reaction layer is beneficial to the improvement of the interface joining strength. Then the interface joining strength of joints can reach 65% of ceramic membranes substrate, fracture occurs mainly in the interface layer between the ceramic substrate and the filler metal.
  • Process Research of RF-ZnO Buffer Layer for Thick GaN Film Growth
    Wang Ru; ;
    . 2011, 42(02): 29-0.
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    RF-ZnO buffer layers for HVPE-GaN thick films were fabricated.Quality of ZnO buffer layers and thick GaN films were characterized by SEM, XRD, AFM and PL. The results showed that RF-ZnO film with (0002) single orientation, clear-grain-boundary and uniform-grain-size microstructure was obtained at the conditions as follows: sputtering power was 60W, Ar gas pressure was 2.0Pa and temperature of sapphire substrate was at room temperature. The FWHM value of (0002) reflection of thick HVPE-GaN film with RF-ZnO buffer layer was 265secarc and yellow luminescence was not observed clear in PL spectrum at room temperature.
  • The property study of porous P(NIPAm-co-AAm) hydrogels prepared by freezing polymerization
    . 2011, 42(02): 30-0.
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    Porous poly(N-isopropylamide-co-acrylamide) [P(NIPAAm-co-AAm)] hydrogels with a very fast thermo-responsive rate were prepared by freezing polymerization method. The internal pore structure and surface morphology of hydrogels were observed by surface area analyzer and scanning electron microscope. The equilibrium swelling ratio and the swelling/deswelling kinetics of the hydrogels were investigated. The in?uence of reaction time of the pre-freezing polymerization on the thermo-responsive rate of the hydrogels was also studied. The results showed that the interconnecting porous network structure had been successfully prepared by the freezing polymerization method. These open pore structures are very useful to accelerate the responsive rate of the hydrogel. The results of swelling properties show that the time of pre-freezing polymerization play a dominant role in the final properties of P(NIPAAm-co-AAm) hydrogel. The equilibrium swelling ratio (SR) of hydrogels reduced with reaction time of pre-freezing polymerization increasing. The lowest critical phase transition temperature (LCST) of P(NIPAm-co-AAm) hydrogels were all around 35 ℃, and different reaction time of pre-freezing polymerization have little effect on it . The swelling/deswelling rate decreased with the reaction time of the pre-polymerization polymerization increasing.
  • Effect of pH on the electrochemical corrosion behavior of reinforcing steel in simulated concrete pore solutions
    ; ;;;
    . 2011, 42(02): 31-0.
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    The passivation and depassivation behavior of reinforcing steel in simulated concrete pore solutions (SPS) with different pH values was studied by the polarization curves, electrochemical impedance spectroscopy and scanning electron microscopy. The results indicated that reinforcing steel was in the passive state in the simulated concrete pore solution with pH 12.50. The lower the pH value of solutions, the more unstable the passive film of reinforcing steel. The critical pH value for the localized corrosion of the reinforcing steel in the simulated concrete pore solutions was between 11.12 and 11.05 based on the electrochemical measurements.
  • Preparation and study of controllable particle size of nickel-doped carbon molecular sieves
    Jin LiuDun Deng;Fenna Zhao;Qingwen Lin
    . 2011, 42(02): 32-0.
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    Nickel-doped carbon molecular sieves (CMS) with controlled particle size have been prepared by the method of inverse suspension polymerization to synthesize poly(furfuryl alcohol) with nickel nitrate as carbon precursor, utilizing template porous nanosilica, through a mild carbonization and post-treatment process . The preparation mechanism and micro-structure of CMS have been characterized through XRD, SEM, N2 adsorption, FT-IR and TGA. The results show that the different carbonization conditions have a definite effect on the particle size and distribution of CMS; Additionally, when the carbonization temperature from 650 ℃ up to 700 ℃, the mesopore volume and the total pore volume raised to 0.40 cm3/g and 0.67 cm3/g, respectively. The micropore volume has expanded twice with the carbonization heating rate increased. The XRD and AAS analysis proved that nickel have been doped into CMS successfully, and 2.24 wt% for doping quantity.
  • Synthesis and Characterization of Poly(γ-benzyl-L-glutamate) / Polyacrylamide Copolymer
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    . 2011, 42(02): 33-0.
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    Allyl-terminated poly (γ-benzyl-L-glutamate)( A-PBLG) was successfully synthesized by the anion ring-opening polymerization of N-carboxy-γ-benzyl-L-glutamate anhydride(Bz-L-Glu-NCA) initiated by allylamine. A-PBLG have many advantages such as good biocompatibility and innocuity of degradation products and having the functional group(allyl) that improves its biomedical application. Acrylamide with good hydrophility was copolymerized with A-PBLG through photo-induced polymerization and amphophilic PBLG-AM was successfully prepared. Strurtcture and property was fully characterized. Results indicated that the hydrophility and biodegradation property of PBLG-AM was improved.
  • Two-steps Prepared Monodisperse Li-doped Y2O3:Eu3+ microspheres and their luminescence properties
    ;
    . 2011, 42(02): 34-0.
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    Y2O3:Eu3+ is the most important red phosphor. In this paper, we prepared monodisperse Li-doped Y2O3:Eu3+ microspheres using a two-step wet-chemical method and investigated their luminescence properties at room temperature. In the method, monodisperse Y2O3:Eu3+ microspheres were firstly prepared by a coprecipitation technique and then Li-doped Y2O3:Eu3+ microspheres were obtained by an ultrasonic-solvothermal method in the LiOH/ethanol mixture. Based on the characterization of scanning electron microscope, X-ray diffraction, and the fluorescence spectrum, it showed that Li-doping could largely decrease the crystallization temperature of Y2O3:Eu3+ and enhance the crystallization level, and as a consequence improve the luminescence of Y2O3:Eu3+.
  • Non-isothermal kinetics studies on the thermal decomposition of g-C3N4 by TG Method
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    . 2011, 42(02): 35-0.
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    Melamine was directly pyrolyzed in semi-closed system to prepare C3N4. The analytic results of XRD, XPS and element analysis(EA) proved that the product is graphite-like C3N4 (g-C3N4). The thermal decomposition processes taking place in g-C3N4 have been studied using TG-DTG technique. The iterative procedure method was employed to calculate the activation energy Eα , integral method with 36 types of kinetic function was proposed to define the most probable kinetic function.The decomposition kinetic parameters were determined, which the average activation energy Eα was 178.59kJ/mol, the most probable kinetic function belonged to g (α) = g(α)=[–ln(1–α)]4, the pre-exponential A was 21.67s-1, and the corresponding thermal decomposition dynamic function was .
  • RuO2.xH2O Electrode Materials Prepared by rotation coating method and Investigation on its Properties
    . 2011, 42(02): 36-0.
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    Abstract: RuO2 film electrodes were prepared by rotation coating method. SEM indicated film thickness is 7.7～8.0μm and the average of adhesion for the film is 18.00 MPa through tensile experiment. XRD microstructure analysis shows the thin film ideal annealing temperature is 270℃.Addition,electrochimica experiment indicated excellent cyclic voltammetry and chronoamperometry and impedance of thin film. The thin film specific capacitance and energy dencity power density and inner resistance are 705.3 F/g、141.05 wh/Kg、0.41 kw/Kg、0.436Ω, respectively.
  • Microstructure and Electrical Properties of (0.94-x) Bi0.5Na0.5TiO3-0.06BaTiO3-xLiNbO3 Lead-free piezoelectric ceramics
    ZHOU FeiLang WU
    . 2011, 42(02): 37-0.
    Abstract ( ) Knowledge map Save
    Abstract: (0.94-x)Bi0.5Na0.5TiO3–0.06BaTiO3–xLiNbO3 (BNBT–xLN, x=0–0.03) lead-free piezoelectric ceramics were prepared by solid state reaction method. The microstructure, ferroelectric, and piezoelectric properties of BNBT–xLN ceramics was investigated. The X-ray diffraction analysis shows that all of the ceramics have single-phase perovskite structure. The grain size becomes more identical and the density increases after the incorporation of certain amount of LiNbO3. For the ceramics with x ≤ 0.02, the remanent polarization (Pr) reduces slightly with increasing x. When x > 0.02, the polar and non-polar phases may coexist in the ceramics at room temperature, resulting in a sharp decline in the Pr and coercive field (Ec). With increasing x, both the dielectric constant (εr) and dielectric loss (tan?) increase gradually, and the piezoelectric constant (d33) increases initially and then decreases. The ceramics with x = 0.02 exhibit the optimum electrical properties: d33 = 150 pC/N, kp = 27%, Pr = 34.1 μC/cm2, Ec = 28.8 kV/cm. The depolarization temperature Td is shifted toward lower temperatures with increasing x.
  • Synthesis and Characterization of a Novel Waterborne Polyurethane 2, 2,-dihydroxyl-4-sodium sulfonyl-6-nitro-azonaphthalene
    . 2011, 42(02): 38-0.
    Abstract ( ) Knowledge map Save
    A novel polymeric dye, waterborne polyurethane 2,2,-dihydroxyl-4-sodium sulfonyl-6-nitro-azonaphthalene (WPU-WAN) was synthesized from poly(propylene glycol) (PPG), 2,4-tolylene diisocyanate (TDI), dimethylol propionic acid (DMPA), 2.2，-dihydroxyl-4-sodium sulfonyl-6-nitro-azonaphthalene（WAN） and triethylamine (TEA) depending on a modified acetone process. FT-IR and UV-visible spectra were used to identify structure of the polymeric dye, indicating weight percentage of chromphores is 12.8% in PU-WAN. The absorption maxima of the polymer showed obviously bathochromic shift (34nm) with contrast to monomer in UV-visible spectra. In addittion the polymer dye has a glass transition temperature (Tg≈74℃) and a two-stage degradation (253～370℃ or 370～550℃).
  • Synthesis and Studies on Photocatalytic Degradation of Bismuthtrioxide Film
    ; ;
    . 2011, 42(02): 39-0.
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    Bismuth oxide films were prepared by DC reactive sputtering. We studied the structure and optical properties of the films and evaluated their photocatalytic activities. The results showed that the ratio of O2 to Ar and annealing treatment could affect the properties of the films. 20:80 was the best ratio of O2 to Ar. The crystallization was enhanced with the increase of annealing temperature. The optimum photocatalytic performance was obtained when the films were annealed at 500℃.
  • Preparation and characterization of spheric micoporous lingin beads
    LI Xianfa
    . 2011, 42(02): 40-0.
    Abstract ( ) Knowledge map Save
    Abstract: With technical kraft lignin as raw materials, the transformer oil as dispersive phase, adding sodium dodecyl sulfate as dispersant and epichlorohydrin as crosslinking agent, spheric micoporous lingin beads were prepared by reversed phase suspension polymerization technique. The suitable process conditions of preparing the lignin beads were determined by signal-factor and orthogonal experiments.The lignin beads were Characterized by Scanning electron microscopy(SEM), fourier transform infrared (FT-IR) and X-ray diffraction Analysis. The results shows that the ideal spherical lignin beads with the 87.75% of the yield and effective diameter 0.6~1.4mm could be obtained under the such conditions as 5g ligin dissolved in 50ml water by adjusting the pH value of the solution 10~13, 0.2g sodium dodecyl sulfate, 3g epichlorohydrin and 200ml transformer oil. Morphology studies show that lignin beads have the full spheric shape and inner porous microstructure. Evidence for the reaction between lignin and epichlorohydrin has been observed by using FT-IR analysis.The results of X-ray diffraction analysis indicate that crosslinked lignin beads is an amorphous polymer.
  • Synthesis and electrochemical characterizations of nanosized manganese dioxides
    ivronwu
    . 2011, 42(02): 41-0.
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    A series of nanosized manganese dioxides have been synthesized via a co-precipitation process with additive of CTAB. SEM result indicated that with additive of CTAB, MnO2 nanosphere with about 20 nm in diameter and a narrow particle size distribution has been obtained, comparable with nanorode morphology with a wide particle size distribution synthesized without CTAB. The adding amount of CTAB has been studied by SEM, XRD, N2 adsorption and desorption and cyclic voltammetric tests. The results found that as the decrease in particle size of MnO2, the specific capacitance of MnO2 increased from 162 to 213 F g-1.
  • Study to Improve Magnetic Properties of Thin Magnets by vaccum annealing
    ;;;Yang Bin;
    . 2011, 42(02): 42-0.
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    Abstract: In the article we have done the research on the influence of the annealing treatment on the surface grains’ strain, micro-structure, sub-crystallite size and magnetic properties of the thin NdFeB magnet by ordering the SEM scanning electron microscope, X-ray diffraction and magnetic Property measurement. The results showed that: firstly,above the three-phase eutectic temperature,900℃×2h+490×5h of annealing treatment can completely eliminate machining strain,stress and defects. Secondly, the capillary action and diffusion of the grain boundary Nd-rich phase uniformly and continuously distributed in the grains and grain boundary around. The Nd-rich phase of this network structure eliminated the grain boundary cracks and defects, and played an important role on the magnetic properties recovery and improvement.
  • Preparation of silicon nanowire arrays by electroless metal deposition method
    YANG Wen Bin
    . 2011, 42(02): 43-0.
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    Large-area regular silicon nanowire arrays (SiNWs) were prepared on silicon substrate by electroless metal deposition method under hydrothermal conditions. Mechanism and effects of morphology control of SiNWs were studied. Morphologies and structures of SiNWs and Ag dendritic crystal were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that morphology of SiNWs could be influenced by solution ratio、temperature and reacting time of hydrothermal system. Large-area SiNWs, which the length is 30-50 μm and the diameter is about 200 nm, can be obtained on condition that temperature is 50℃, and concentrations of HF and AgNO3 are 4.6mol/L and 0.02mol/L, respectively. The electroless metal deposition method is a kind of simple, moderate technology for preparation of silicon nanowires and SiNWs.
  • Influence of Annealing Process on BiFeO3 Films by Liquid Phase Self-assembled Method
    ;;
    . 2011, 42(02): 44-0.
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    OTS as stencil,BiFeO3 films were successfully prepared on ITO/glass substrates by Liquid Phase Self-assembled Method using Bi(NO3)3?5H2O,Fe(NO3)3?9H2O and citrate acid as raw materials.The influence of annealing temperature and holding time on BiFeO3 films were studied.The crystalline behavior of BiFeO3 precursor particles were characterized by DSC/TG,the phase and surface morphology of BiFeO3 films prepared under different annealing process were characterized by XRD and FE-SEM.The results indicated that:the crystalline transition temperature of crystalline BiFeO3 films are around 440℃;the pure phase BiFeO3 films are actually obtained after annealing at 550℃ for two hours,the surface of the films are smooth and dense, the grains are completely developed and well-distributed, no obvious defect could be seen;grains would grow abnormally and impurity phase would forms when the annealing temperature is too high; BiFeO3 would pyrolyses when the holding time was too long.
  • Investigation on the electronic structure of La2Ni7 and LaMgNi7 hydrogen storage alloys
    Lin Yu-Fang
    . 2011, 42(02): 45-0.
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    Density functional theory calculation have been performed on the electronic structure of La2Ni7 and LaMgNi7 hydrogen storage alloys. We discussed the relationship between microstructure and characteristics of the alloys. The result show: the bonding of N-Mg in the system of LaMgNi7 is formed, and the system stability is higher than that of La2Ni7. The bonding of Ni-Ni in LaMgNI7 is weaker than that in La2Ni7 system, so the energy-barrier when H atom diffusing in the system is lowered, then the dynamics is improved and the hydrogenation plateau is reduced.
  • Hydrogen storage kinetics of nanocrystalline and Mg2Ni1-xCux (x = 0-0.4) alloys prepared by melt spinning
    Yanghuan Zhang ;;;;
    . 2011, 42(02): 46-0.
    Abstract ( ) Knowledge map Save
    The nanocrystalline Mg2Ni-type Mg2Ni1-xCux (x = 0, 0.1, 0.2, 0.3, 0.4) alloys were synthesized by the melt-spinning technique. The influence of the melt spinning on the structures and the hydrogen storage kinetics of the alloys were investigated. The structures of the as-cast and spun alloys were studied by XRD, SEM and HRTEM. The hydrogen absorption kinetics of the alloys was measured using an automatically controlled Sieverts apparatus. The high rate discharge ability (HRD) of the alloy was measured by an automatic galvanostatic system. The electrochemical impedance spectrums (EIS) and the semilogarithmic curves of anodic current versus time responses of the alloy were plotted by an electrochemical workstation, and the hydrogen diffusion coefficients (D) in the alloys were obtained by virtue of potential-step method. The results show that all the as-spun alloys display a nanocrystalline structure. The substitution of Cu for Ni does not change the major phase Mg2Ni. The melt spinning significantly improves the hydrogen storage kinetics of the alloys. Both the hydrogen absorption kinetics and the high rate discharge ability (HRD) increase with growing the spinning rate.
  • Preparation and microstructure of MCMB in silicone oil dispersion system
    Zhen WANG
    . 2011, 42(02): 47-0.
    Abstract ( ) Knowledge map Save
    Mesocarbon microbeads (MCMB) were prepared by heat condensation in the retort with coal tar pitch and silicone oil as the dispersion and heat exchange medium. The influence of silicone oil on the preparation of MCMB was studied by Polarized microscopy, SEM and TEM. The results showed the heating temperature and holding time had important influence on the formation of MCMB. MCMB were obtained at 350-380℃, and polarized microstructure changed, the diameter and yield increased with holding time prolonging. The building units of MCMB were molecular layer, and the structure was Brooks-Taylor type. Furthermore, Optimum conditions were as follow: the heating temperature was 380℃, and the holding time was 2h.
  • Preparation and Infrared Emissivity of Bi2O3/ATO Mixed Burning Filler
    ;;Han Peng De
    . 2011, 42(02): 48-0.
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    Bi2O3/ATO powders were prepared by solid state reaction. The phase composition, reflectivity in visible region, morphology, elemental composition, infrared transmittance and infrared emissivity of the obtained Bi2O3/ATO powders were characterized by XRD, ultraviolet-visible spectrophotometer, SEM, EDS, FTIR and infrared emissivity analyzer, respectively. The results showed that the obtained Bi2O3/ATO powders possessed excellent infrared transparency. Moreover, infrared emissivity decreased first and then increased with the increase of the Bi2O3 contents, and infrared emissivity reached the minimum 0.67 when the content of Bi2O3 was 70 wt%. In addition, the colors could be adjusted by changing the content of Bi2O3. Bi2O3/ATO powders were suitable for preparing the multicoloured infrared camouflage packing.
  • Effect of H3BO3 Flux on Luminescent Properties of SrAl2O4:Eu2+, Dy3+, Pr3+Prepared by Combustion Synthesis
    . 2011, 42(02): 49-0.
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    SrAl2O4:Eu2+, Dy3+, Pr3+long afterglow phosphor were prepared by combustion at lower temperature (600~620℃),using nitrate and carbamide as starting materials. The effect of H3BO3 on the phase composing、crystal structure, luminescence capability and long afterglow characteristic of SrAl2O4:Eu2+, Dy3+, Pr3+ was investigated in this paper. When mass percentage of H3BO3 was 0.65％, it played a great role in stabilizing SrAl2O4 phase and greatly improving the initial brightness and luminescence properties of powder judged from the XRD patterns, excitation and emission spectra, decay curves, mictocosmic structure of SrAl2O4:Eu2+, Dy3+, Pr3+ phosphor. The sample had the characteristics of loose texture, good crystal, uniformity mixed and good luminous intensity.
  • Photoelectric Properties of Cellulose / CdS Nano-composites Prapared by Sonochemical method
    . 2011, 42(02): 50-0.
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    Microcrystalline cellulose (MCC)/CdS nanocomposites were prepared by sonochemical process using cadmium chloride and sodium sulfide as raw materials and MCC as matrix. The structure and properties of obtained MCC/CdS nanocomposites were characterized by means of atomic force microscopy（AFM）, X-ray diffraction (XRD) and fluorescence spectrum (PL). The as-prepaered MCC/CdS nanocomposites was immobilized on the surface of indium tin oxide (ITO) electrode and its electrochemical properties were investigated by photoelectrochemical experiments. According to AFM images, micro-nano-CdS particles are evenly distributed on the surface of microcrystalline cellulose, with the size of 30-70 nm. XRD indicate that CdS is cubic phase and the PL peak observed from CdS nanocomposites is 525 nm. Through photoelectrochemical experiments, the stable photocurrent characteristics is examined.
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