25 May 2011, Volume 42 Issue 05
    

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    研究与开发
  • Structure and IR optical property of nitrogen-rich MeNx（Me=Ti、Zr、Hf）films
    ;;;;
    . 2011, 42(05): 1-0.
    Abstract ( ) Knowledge map Save
    MeNx（Me=Ti、Zr、Hf）films have been prepared by using the reactive radio frequency magnetron sputtering technique, and the N2/Ar flow rate ratio of the process has been systematically varied, so that its effects on structure and optical properties of the films could be studied. Results of X-ray diffraction experiments showed that the nitrogen-rich TiNx films are mainly composed of TiN phase, but the nitrogen-rich MeNx（Me=Zr、Hf）films are amorphous in their structure. Optical transmittance of the MeNx（Me=Ti、Zr、Hf）films was measured in the wavelength range of 0.4~12.5 ?m, and the results show that the TiNx films were opaque, but the ZrNx and HfNx films were transparent, especially in the infrared regimes. The results also proved that the variation in the N2/Ar flow rate ratio had little effects on the structure as well as the optical properties of the MeNx（Me=Zr、Hf）films. It is also found that HfNx films deposited on ZnS substrates could significantly increase the surface hardness of the samples, and at the same time, the films would maintain the transmittance of the ZnS material. Therefore, HfNx films have the potential to become a new material for protecting ZnS infrared windows.
  • Investigation on the mechanical Lapping and polishing of CdZnTe Wafers
    ;
    . 2011, 42(05): 2-0.
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    In this paper, the mechanical lapping and polishing processes of Cadmium Zinc Telluride (CZT) wafers were investigated. Adopting the Al2O3 powder with different diameter, the CZT wafers were mechanical lapped and polished, considering the parameters of lapping pressure, lapping plate rotation, and duration times. Then the surface quality, roughness, lapping and polishing rate were investigated by means of metallographic microscope, atomic force microscope and micrometer measurement. The results showed that, with the 2.5 ?m diameter Al2O3 powder, the optimal lapping pressure and plate rotation speed were 120 g/cm2 and 75 r/min respectively, and lapping rate was 1 ?m/min. Under the mechanical polishing with 0.5 ?m Al2O3 suspension, the optimal concentration of Al2O3 suspension was 6.5 wt% with the polishing rate of 0.28 ?m/min. The AFM measurement showed that, after lapping, the roughness Ra value of CZT wafers was 13.83 nm, then after polishing for 4 hours the Ra value decreased to 4.22 nm.
  • Fabrication and characterization of quasi-regular arranged porous silicon
    ;Xueming Li ;;
    . 2011, 42(05): 3-0.
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    Abstract: The regularity of pore arrangements of porous silicon prepared by electrochemical process depends sensitively on the anodization parameters. In this work, self-assembly quasi-regular pore arrangements have been fabricated by electrochemical anodization without prestructuring or PAA template. Effect of electrolyte composition, HF mass fraction and anodization time on morphology of porous silicon is analyzed respectively. The result shows that the pore depth increases, the pore diameter increases firstly and then stable, with the increasing of anodizing time. When the mass fraction of HF and dimethylformamide is 20:80, the current density is 75mA/cm2 and anodic oxidation time is 5min, the as-prepared porous silicon has quasi-regular pore arrangements, pores grow perpendicular to the surface and parallel to each other, they have almost the same size and depth. The pore diameter is about 1μm and pore depth being capable of reaching 20μm.
  • Influence of several carbon source on Ti(C, N) powders prepared by carbothermal reduction and nitridation method
    Peng-Fei YU
    . 2011, 42(05): 4-0.
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    Ti(C, N) powders can be prepared by carbothermal reduction and nitridation method with the nanometer TiO2 and different carbon source as starting materials. X-ray diffractometer, TG/DSC thermal analyzer, SEM and chemical analysis are applied to investigate the reaction mechanism on carbothermal reduction-nitridation of TiO2 and the effects of different cardon source on preparation of titanium carbonitride powders. The results show that, in the reaction process, the predominant reaction mechanism is TiO2/C solid-solid reaction in the beginning and subsequent the gas-solid reaction in which CO participates. The reaction of mixtures with carbon black as the carbon source is more complete than those with active carbon and graphite, and the former is finer than the latter two in the grains of reaction products. At the same time, with the specific surface area of carbon black increasing, the carbon/nitrogen ratio declines, and the free carbon content and oxygen content decrease. Moreover, if the mixtures with carbon black specific surface of 600m2/g as the carbon source and a carbon content of 28.8% were isothermal treated for 3 hours at 1700℃ in an atmosphere of nitrogen flow at 1000ml/min , TiCN powders with free carbon content <0.2%, oxygen content<0.5% ,and total carbon content =11.42% can be synthesized.
  • Preparation of polylactide asymmetric membrane and its osteoblasts affinity
    ;;Xianglin Luo
    . 2011, 42(05): 5-0.
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    Poly (L-lactide) (PLLA) with different molecular weight were synthesized by ring-opening polymerization of L-lactide, with which asymmetric porous membrane with a porous side and a dense side were prepared by a molding technology of ammonium bicarbonate foaming. The SEM confirmed the asymmetric structure of the membrane : one porous side with lots of interconnected pores ranging from 50 μm to 500 μm and one dense side with some small pores ranging from 1 μm to 5 μm. Mechanical properties test showed that tensile strength of PLLA membrane reduced with the decrease of molecular weight PLLA and the increase of ammonium bicarbonate content. Culture of osteoblasts in vitro demonstrated that PLLA asymmetric porous membrane had good osteoblasts affinity. These results suggest that the membranes are promising for bone tissue guide membrane application.
  • Study on the Hydrophilicity of Porcine Acellular Dermal Matrix Crosslinked by Glycerol Polyglycidyl Ether
    DAN Nian-hua
    . 2011, 42(05): 6-0.
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    Porcine acellular dermal matrix (pADM) was crosslinked by serial dosage 0%, 5%, 10%, 20%, 40%,100% (wt/wt) of glycerol polyglycidyl ether (GPE). The properties of them were characterized with shrinkage temperature（Ts）, hygroscopicity, rate of absorbed water, water retentivity, contact angle, FT-IR, XPS and SEM before and after crosslinked. With the increase of GPE concentration, Ts of GPE-pADM was enhanced obviously. The holes of GPE-pADM tended to shrink after crosslinked from the SEM images of the material surface, and it resulted in the fall of the rate of absorbed water and hygroscopicity. Improvement of surface hydrophilicity was proved by the decline of contact angle in the surface of GEP-pADM. Consistent with the principle of GPE crosslink reaction, the added polar bond, aliphatic ether bond and C-O bond, were discovered by the shape (about 1083cm-1) change of IR spectroscopy curves and the increase of content of oxygen were observed by XPS. All of these promoted the increase of combined water and decrease of contact angle. These proved that hydrophilicity of pADM was increased after crosslinked by GPE.
  • Magnetization and Faraday effect of Cd0.8Mn0.2Te single crystal
    . 2011, 42(05): 7-0.
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    The Cd0.8Mn0.2Te single-crystal ingot was grown by the vertical Bridgman method. The magnetization (M) measurements of Cd0.8Mn0.2Te sample was performed at 2 K under external magnetic field (H) from -20 to 20 kOe, and at 10 Oe from 2 to 200 K with magnetic field cooling and without magnetic field cooling respectively, using the superconducting quantum interference device (SQUID) magnetometer. Faraday rotation as a function of photon energy for Cd0.8Mn0.2Te crystal was measured at 300 K under magnetic field less than 0.2 T. The M-H analysis indicates that there is an antiferromagnetic interaction between Mn2+ ions in the crystal. The results of susceptibility vs temperature fit Curie-Weiss laws at temperatures above 40 K and a deviation from the Curie-Weiss law at temperatures from 2 to 40 K, which indicate Cd0.8Mn0.2Te crystal possess paramagnetic properties in the temperature range from 2 K to 200 K and the paramagnetism enhances with the temperature decrease below 40 K. The results of Faraday rotation show that Cd0.8Mn0.2Te has a Verdet constant up to 2×103deg/cm.T and a single-oscillator model fits the data very well with the exciton energy E0=1.831eV, which proves that the sp-d exchange interaction is the main reason that introduces Faraday rotation to Cd0.8Mn0.2Te.
  • First principle studies of electronic structures and red shift effect heavily N-doped rutile TiO2
    HOU QING-YU
    . 2011, 42(05): 8-0.
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    Abstract By adopting the ab-initio study of plane wave ultra-soft pseudo-potential technique based on the density function theory (DFT), we presented geometric structure optimizations, as well as calculations of band distribution, density of states and absorption spectrum, on heavily N-doped rutile TiO2 supercell models as well as non-doped TiO2 ones.. Calculation results show that, when the concentration of N equals x=0.0625, N 2p state and O 2p state hybrid couples together, causing valence band shifting up, minimum band gap narrowing, and absorption spectrum red shifting, which is consistent with similar effects in experiments on heavily N-doped TiO2.
  • Effects of Nb and Zr substitution content on the boundary phases and the coercivity of powder sintered Nd(Dy,Gd)-Fe(Nb,Zr,Al,Cu)-B magnets
    ;PAN JingXin-cai LIU;;;
    . 2011, 42(05): 9-0.
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    Nd(Dy,Gd)-Fe(Nb,Zr,Al,Cu)-B powder sintered magnets with 0.8at%Nb+0.9at%Zr or 1.5at%Nb+1.2at%Zr were prepared. The effects of Nb and Zr substitution content on the formation of intergranular phases and the relationship between the intergranular new phases and the coercivity have been investigated on the analysis basis of microstructures, micro-area compositions and magnetic properties of the magnets. The results show that, in the magnets with 0.8at%Nb+0.9at%Zr, a new grey boundary phase with high content of Nb and Zr elements is formed, accordingly the intrinsic coercive force of the magnets is 1900 kA?m-1. And in the magnets with 1.5at%Nb and 1.2at%Zr, in addition to the new grey boundary phase, a new kind of block NbFe phase with round or polygonal morphology, about 2μm, appear in magnet boundaries. This makes the intrinsic coercive force of the magnets further increases to 2229.3 kA?m-1.
  • Preparation and properties of nano-aluminum hydroxide/ Calcium alginate fibers
    . 2011, 42(05): 10-0.
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    Calcium alginate fiber and nano-aluminum hydroxide/calcium alginate fiber have been prepared by wet spinning process. Field emission scanning electron microscope and the IR of the two fibers showed that nano-aluminum hydroxide particles dispersed in sodium alginate well and formed a package structure, thus the strength of nano-aluminum hydroxide/calcium alginate fibers have been greatly enhanced because of the existence of the nano-alumina hydroxide particles. The thermal stability of the two fibers were characterized by thermal gravimetric analyzer test , The results showed that the thermal stability of the composite fiber was superior to that of calcium alginate fiber.
  • Study on the synthesis and properties of nano-TiO2 co-doped with N, Fe
    Yan-hua Liu
    . 2011, 42(05): 11-0.
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    A nanosized TiO2 photocatalyst co-doped with N, Fe was synthesized by the sol-gel method. The prepared samples were characterized by XRD and XPS. The grain size, grain surface area and lattice distortion for the samples were analyzed and the effect of N, Fe co-doped in TiO2 was studied. The results showed that the change from anatase to rutile transformation with temperature was inhibited by N, Fe co-doped and the phase transfer of TiO2 was significantly delayed. By N and Fe co-doping, the grain size was clearly reduced, and the surface area of photocatalyst was clearly increased. Regardless of doping or not, as the calcination temperature was increased the grain size of TiO2 was increased and the surface area was reduced, but non-doped TiO2 showed larger grain size and smaller surface area. After N and Fe being doped the effect of the temperature on TiO2 decreased. In the crystals of the nano-TiO2 co-doped with N and Fe, N existed with the bonds of Ti-N and N-O and Fe existed in Fe2O3. With the increasing of calcination temperature, the grain size of the prepared nanopowder simples increased, and the grain surface area and the lattice distortion decreased, then the doping effect was lowered.
  • In situ Preparation and Property of Nano-Ag / PMMA Composite Film
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    . 2011, 42(05): 12-0.
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    In situ preparation of silver nano-particles in polymethylmethacrylate (PMMA) using N, N-dimethylformamide (DMF) as a medium has been performed successfully. Nano-Ag/PMMA composite film was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), UV-Vis absorption spectrum (UV-vis). The results showed that: the sample exhibits a typical face-centered cubic(fcc) silver phase, and with the reaction time increasing, the nano-silver particles sizes increased gradually, by the shaps changed spherical into nanoprisms. In the composition film, there was a certain mutual chemical reaction between the nano-silver particles and the PMMA martix, which lead to the nano-silver particles existenced in PMMA matrix stably and distributedly, and the film obviously had optical absorbtion in UV-Vis for SPR(Surface Plasma Resonace) of nano-sliver.
  • Error Analysis of Dipole Approximation in Magnetorheological Fluid
    Zu-Zhi TIAN ;
    . 2011, 42(05): 13-0.
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    Abstract: To improve the accuracy of calculating the rheological behavior of magnetorheological fluid by dipole approximation, the limits of validity for dipole approximation is analyzed by the method of comparing the dipole model with the finite element model, the errors of dipole approximation of magnetorheologcial fluid with different volume fractions are calculated. The results indicate that the particles are mainly affected by the adjacent particles, the maximum relative error of dipole approximation appears in the point nearing the adjacent particle and the value is 62%. When the volume fraction of magnetorheological fluid is 6.5%, the maximum error of dipole approximation is 3% and the dipole model is valid; while the volume fraction is 20%, the maximum error change to 19% and the dipole model is invalid. The external magnetic field has influence on the error of dipole approximation, the stronger the magnetic field, the little the relative error.
  • The research of LSCM/3YSZ mixed ionic-electronic
    Jie ZOU ;;;
    . 2011, 42(05): 14-0.
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    A series of ionic-electronic conductors were made by compound different quality of LSCM（La0.75Sr0.25Cr0.5Mn0.5O3）and 3YSZ. The physics characteristics of MIECs were tested by X-ray diffraction, SEM and thermal expansion analysis etc. The LSCM forms a connected space network and there are impurity phases as a result of the reaction between Zr and Sr or Cr, with the increase of LSCM content. When the percentage content of LSCM is 0~40%, each thermal expansion curves have a clear inflexion in the temperature range from 0 to 1350℃.The conductivities of ion and electron are tested by wagner DC polarization method. When the LSCM percentage content reach 40%, the ionic and total conductivities are increased quickly, when the LSCM percentage content is 50% and the test temperature is 800℃, the total and ionic conductivities are 0.24S/cm and 0.08S/cm, respectively.
  • The MBE Growth Research on InGaAs/GaAs Heterofilms
    Luo Zijiang;
    . 2011, 42(05): 15-0.
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    This paper reports an experiment research which utilized of the molecular beam epitaxy technology to grow the InGaAs / GaAs film, the film growth conditions was monitored through the RHEED patterns in real-time, we measured the growth rate and determined the composition of In/Ga in InGaAs / GaAs film by RHEED intensity oscillations, and then put forward a method to control the composition of In/Ga in InGaAs / GaAs film. According to the RHEED patterns，the surface of InGaAs film was (2 × 3) reconstructed. After growth, the sample was quenched down and transferred into STM for scanning, a smooth, atomically flat surface of InGaAs / GaAs film was confirmed by the STM images.
  • Biocompatibility Evaluation of a New Bone Graft Material-Poly(amino acids)/Calcium Sulfate Composite
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    . 2011, 42(05): 16-0.
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    PAA/CS composite was synthesized by melt polycondensation process. The PAA/CS plate and its extract were co-cultured with L929 cells for observation of the cells morphology. The proliferation activity of the L929 cells was quantified by a CCK-8 kit and the growth circle of the cells was determined on the flow cytometry. The compact PAA/CS cylinders were implanted into the proximal tibia in rabbits for macroscopical and histological observation. The results indicate that the PAA/CS composite and its extract has no influence on the L929 cell growth, and the cytotoxicity of PAA/CS composite is under level 1, which meets the national requirement for biomaterial. The PAA/CS composite is of excellent tissue compatibility and bioactivity that can guide new bone ingrowth and form bony bond with host bone, without any visible foreign body rejection.
  • Insulating Function of Asphalt-based Composites with Porous Aggregate
    . 2011, 42(05): 17-0.
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  • The high-frequency electromagnetic and microwave absorption properties of Nd-doped BaTiO3
    Jian XIONGDENG Lian Wen
    . 2011, 42(05): 19-0.
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    Nano-particles of Nd-doped BaTiO3 were prepared by modified sol-gel method. The microstructure and high-frequency electromagnetic properties were characterized by using X-ray diffraction(XRD),vector network analyzer. The results showed that Nd-doped barium titanate samples crystalline sound with annealed 1h at 700℃. With the increase of Nd content, the lattice size of the BaTiO3 powders decreased with the grain refinement. Within the bandwidth of 2-18GHz, the real part of dielectric constant of 5% Nd-doped BaTiO3 powders decreased slightly with the stability improved, but the imaginary part of dielectric constant greatly increased. Both the peak of the Complex permittivity and permeability has blue shift with Nd-doped. The reflection loss of 5% Nd-doped BaTiO3 powders is greatly increased and reflection peak has blue shift compared with pure BaTiO3 powders. The above shows that Nd-doping can greatly improved the microwave absorption properties of the BaTiO3.
  • Research on microstructure and property of surface aluminum-alloying layer of magnesium alloy
    Xiong ZHANG;CHEN dong fengCHEN Dong Feng
    . 2011, 42(05): 20-0.
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    An aluminum-alloying layer was fabricated on magnesium alloy surface by the method of lost foam casting. And microstructure, composition, phase and corrosion property of the surface alloying layer were also analyzed. The results show that the thickness of the layer is 750μm and coverage of the new phase reaches to 76.2% when the vacuum degree was 0.08Mpa and the particle size of Al powder was 150μm. The main phase of the surface alloying layer which shows chrysanthemum or mesh structure and is metallurgical bonded with the substrate is Mg17Al12, Mg and Al. The corrosion property of surface alloyed magnesium alloy is improved. Only when the coverage of the new phase is greater than the critical value of 37.1%, the surface alloying layer can play a role in anti-corrosion and the higher the coverage is, the better the corrosion resistance will be.
  • Influence of Concrete Constituents on Creep Characteristics of Concrete at Same Compressive Strengths
    HE Zhi Hai
    . 2011, 42(05): 21-0.
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    The influence law of polyvinyl alcohol (PVA) fiber, shrinkage reducing admixture (SRA) and the combined addition of fly ash and slag on creep characteristics of concrete with 7 days same compressive strengths were studied by the self-made creep loading device and the influence mechanism were analyzed by testing chemically combined water of paste with same water-binder ratio with concrete. The results indicate that creep coefficients develop rapidly, becoming stable after 100 days’ loading; SRA and the combined addition of fly ash and slag significantly reduce creep coefficients of concrete, the better effect with SRA, the value of 450 days only being 0.63, but PVA fiber increases creep coefficient, not suitable to produce concrete for high speed railway; creep coefficients of concrete decrease with the rise of chemically combined water of paste, and hydration at 60 days early ages is in favor of reducing creep coefficients but hydrated products at 450 days later ages can not make contribution to reducing creep coefficients.
  • Preparation of Oxidized alginate sodium cross-linked chitosan scaffold for drug delivery
    Xu Zhang;;;;
    . 2011, 42(05): 22-0.
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    To obtain a novel composite drug delivery system (DDS), chitosan (CS) microspheres were firstly prepared by emulsion cross-linking method. Then these microspheres mixed with Calcium polyphosphate (CPP)/ CS composite particles were crosslinked with oxidized alginate sodium (ADA) by using the method of freeze-drying. The properties were characterized by the methods of infrared spectra (IR), scanning electronic microscope (SEM) and in vitro drug release. The results shows that CPP are distributed uniformly into CS phase and properties of CPP and CS are stable in the DDS. Pores are distributed uniformly in the system and have high interconnection. CS microspheres (5-50μm) in the system have smooth surface and dense spherical integrity. This research will offer a new kind of carrier with good properties for bone tissue engineering and for the sustained release of drug which will have great potential to be used for bone or cartilage repair.
  • Luminescent characteristics of KCaPO4:Tb3+ green phosphor
    . 2011, 42(05): 23-0.
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    A green phosphor, KCaPO4:Tb3+, was synthesized by the high temperature solid state reaction method. Li2CO3, Na2CO3, K2CO3, CaCO3, NH4H2PO4, NH4Cl, Tb4O7 and CeO2 were used for starting materials. After these individual materials were blended and grounded thoroughly in an agate mortar, the homogeneous mixture was heated at 900℃ for 3 h, and then the phosphors were obtained. The phase present of the samples was characterized by a powder x-ray diffraction. The spectral characteristics of the phosphors were measured by a SHIMADZU RF-540 fluorescence spectrophoto- meter. KCaPO4:Tb3+ shows several emission peaks, and locates at 437, 490, 545, 587 and 623 nm, which correspond to the 5D3→7F4 and 5D4→7FJ=6. 5, 4, 3 transition of Tb3+, respectively, and the main emission peak is 545 nm. Monitored at 545 nm emission, the excitation spectrum consists of several bands, and the main peak locates at 380 nm. The effects of Tb3+ doping content, the compensators (Li+, Na+, K+ or Cl-), and the sensitize activator Ce3+ on the emission intensity of KCaPO4:Tb3+ phosphor were studied. The results show that the emission intensity can be enhanced by select the prime condition.
  • Synthesis and Properties of Novel Conjugated Polymers Based on Carbazole and Indolocarbazole
    . 2011, 42(05): 24-0.
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    Two novel conjugated polymers based on carbazole and indolocarbazole were synthesized via Suzuki coupling reaction. The resulting polymers present high molecular weights, good thermal and electrochemical properties. The photophysical properties show that the prepared polymers are potential pure blue light emitting materials.
  • Structure and properties of double crosslinking waterborne polyurethane
    . 2011, 42(05): 25-0.
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    Ketone hydrazine crosslinking and silane coupling waterborne polyurethane(WPU) was prepared by using DDP as chain expanders and KH550 as end capping agent. The structure and property of the WPU films was confirmed by means of ATR-FTIR and TGA. FTIR results indicated that the reaction between ketone carbonyl and hydrazine has happened during the film curing. TGA indicated that thermal stability of the films are improved by increasing DDP and KH550 content. when w(KH550)=10% and DDP content increases, tensile strength increases from 20.09MPa to 29.56MPa, water absorption of the films decreases from 32.36% to 18.92%, acetone absorption also decreased. water contact angle of WPU films increases from 63.15° to 82.20° with increasing w(KH550). when w(DDP)=6.08% and w(KH550)=10%, the prepared double crosslinking WPU are endowed with good application properties. The pencil hardness of the WPU reached 2H, pendulum hardness reached 0.85, adhesive force grade reached the 0 level and impact resistance was up to GB/T1732-93.
  • High salt rejection nanofiltration membrane prepared by Poly(amidoamine) (PAMAM) dendrimer
    huiyu DENG
    . 2011, 42(05): 26-0.
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    N-(2-aminoethyl)-piperazine cored amine-terminated poly (amido-amine) (PAMAM) dendrimer was synthesized by divergent procedure. A series nanofiltration (NF) membranes with high salts rejection were prepared with PAMAM and trimesoyl chloride (TMC) via in situ interfacial polymerization. Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were applied to characterize the NF membranes. Water contact angle was also employed to evaluate the hydrophilicity of the resulting membranes. The results indicated that membrane became more compact by using higher generation PAMAM, increasing the PAMAM concentration or prolonging reaction time which lead to higher salt rejection. The salt rejection coefficient of Na2SO4、MgCl2、MgSO4 reached 93.0%，92.3% and 91.4%, respectively for the membrane prepared by NG2 dendrimer (4.46×10-3 mol/L). It should be noted that the increase of PAMAM concentration resulted in the amount of acyl chloride group changed from excess to relatively less than amino group which greatly affected the salt rejection order of NaCl、Na2SO4、MgCl2 and MgSO4.. The MgCl2 rejection changed from lower to higher than and then nearly equal to that of Na2SO4 and MgSO4, all of them finally reached more than 90%.
  • Microstructure and electrical properties of Mn-Co-Zn-Cu-O NTC thermistors
    学平 chai
    . 2011, 42(05): 27-0.
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    Series of Mn2.3Co3.7ZnxCuyO4（x=0、0.03、0.06；y=0、0.05、0.08、0.1、0.2）were used as negative-temperature-coefficient (NTC) thermistor. The microstructure and electrical properties of the samples were studied by EDS、SEM and FTIR. The results indicate that series of Mn-Co-O NTC ceramics with the relatively low electrical resistivity and high B constant were obtained by adding ZnO、CuO, when the x=0.03，y=0.05 led to the desired electrical parameters. The added Zn+ cations have a strong tendency to place themselves on the octahedral sites of the spinel lattice and lead to an increase in electrical resistivity and the B constant，but Cu2+ ions occupy both octahedral and tetrahedral sites and cause an decrease in those parameters . At the same time, we find that segregation of CuO occur at the grain boundary.
  • Surface modification of aluminum for improving bonding strength between PPS and aluminum
    WANG SHI XI; ;
    . 2011, 42(05): 28-0.
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    Abstract: The aluminum surface was pre-treated in order to improve the bond strength between the Polymer and Aluminum without gluing. The surface wettability and microstructure of the treated surface were examined using contact angle and SEM, and the surface component was analyzed using EDS. The bonding strength was studied with single overlapped tensile shear testing and vertical tensile testing. The results showed that after the process of sodium hydroxide etching and hydrazine hydrate polarizing, the contact angle had reduced obviously, and the rough surface with compact oxide film can be obtained. The aluminum roughness surface can form mechanical adhesion, and the oxide film can react with polymer and connect with covalent bond. Compared with the non-treated samples, the treated samples have higher bonding strength and durability, and this process is a promising pre-treatment for bonding between polymer and aluminum without gluing.
  • Synthesis of Amide-Containing Ferrocenyl Organometallic Third-order Nonlinear Optical Materials
    ; ;;
    . 2011, 42(05): 29-0.
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    A series of 7 amide-containing ferrocenyl organometallic third-order nonlinear optical materials were synthesized via carboxylation, acyl chlorination and N-acylation. Two new materials were reported. The yield 41%~92%. The structure of the materials were confirmed by IR, 1H NMR and MS. The UV-vis absorption spectra of the materials were determined and the third-order optical nonlinearity was measured by optical path of degenerate four-wave mixing.
  • The study on structure and properties of fluorocarbon films prepared by RF magnetron sputtering at varying target-substrate distance
    Zeng-Ji LIU ;; ;
    . 2011, 42(05): 30-0.
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    Fluorocarbon films were prepared by RF magnetron sputtering on regenerated cellulose substrate, we used PTFE as the target and used as the working gas. The atomic force microscope (AFM) was employed to determine the morphology of the surface. The function parts of the surface were checked by XPS. And the contact angle was measured by the static contact angle testing apparatus. The experiment showed that the fluorocarbon films were islands-structure composed of nanometer particles. The surface of islands was not flat. The regenerated cellulose films were covered with fluorocarbon films which consisted of four components:—CF3—, —CF2—, —CF—and—C—, The ratio of fluorine to carbon (F/C) of films drops from 0.551 to 0.427 and the contact angle drops from107°to 75°with increase of the target-substrate distance from 30 to 80 mm, decreased the target-substrate distance is beneficial to enhance hydrophobicity of fluorocarbon films.
  • Simulation and experimental measurement of local performance of anode supported solid oxide fuel cell
    jie wang ;;;;;;
    . 2011, 42(05): 31-0.
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    In order to prepare high performance large size anode-supported planar solid oxide fuel cell (SOFC) and avoid the gas distribution difference during the test, in this research single cell with dimension of 10×10 cm2 (active reaction area of 9×9 cm2) was divided into 9 independent segments (each segment with dimension of 2.8×2.8 cm2) to measure the local performance and temperature. Each segment was measured independently about the current-voltage curve and the local temperature. For comparison, computational fluid dynamics (CFD) was used to simulate the gas distribution in the cathode side. Both the simulation and experimental results show an inhomogeneous distribution of gas during the test. This work is crucial to design large size SOFC single cell with optimization of the gas distribution layer.
  • Preparation and Properties of Continuous Porous Polyacrylamide Gels from Bicontinuous Microemulsions
    ZHOU Ying-Xue
    . 2011, 42(05): 32-0.
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    Organogel, hydrogel and an organo/hydro hybrid gel were prepared by bicontinuous microemulsion(BME) template of sodium dodecyl sulfate (SDS)/toluene/ 2-butanol/saline. 12-Hydroxystearic acid (12-HA) was organogeltor. These gels were self-supported, and aqueous and oil microphases bicontinuously coexisted and were immobilized in the gels. Particles dimenters and polydispersion of BME solution were detected by static light scattering (SLS) and dimenter was 8-800nm. Morphology constructure of gels were observated by scanning electrinic microscopy (SEM) and was continuous porous networks. Several peaks were measured of gels tested by differential scanning calorimetry (DSC) and thermogravity (TG) for thermal properties due to bicontinuous microemulsion composites. Compared to pure cross-linked polyacrylamide, the swelling ratio and swelling saturated times of BME hydrogel were instrictly decreased.
  • The effects of growth temperature on the properties of Cd1-xZnxTe prepared by close-spaced sublimation
    YUAN Yan-yan;;;
    . 2011, 42(05): 33-0.
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    Abstract: The Cd1-xZnxTe polycrystalline thin films were deposited by Close-spaced Sublimation(CSS) with the powders sources Cd1-xZnxTe.The influence of growth temperature on the growth rate, structure and properties of thin films were studied by analysising the film with SEM, XRD, UV spectrophotometer and so on. The results showed that the growth rate increased with the temperature increases and increasing rate speed up above the 528℃. The Cd1-xZnxTe thin films prepared at of the different temperature possess cubic structure, and tend to grow along the orientation of (111) face. The crystal size increases with the increases of temperature which reaches the 1μm and 20μm at the 438℃ and 568℃ respectively. The opitcal energy gap of all the films are in the region of 1.49 eV-1.51 eV.
  • Application research of a cathode prepared with ketjen black as conductive additives in LiFePO4 batteries
    Jie ZHANG
    . 2011, 42(05): 34-0.
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    SEM, constant current charge-discharge test, EIS were used to evaluate the influence of the amount of KB and the way of KB was dispersed in slurry on the adhesive force of cathode plates ,and to evaluate the charge-discharge properties and cycle performance of batteries, and compared the electrochemical behavior of LiFePO4 batteries prepared with ketjen black and acetylene black as conductive additives. The results indicate that high speed shear can solve the agglomeration of the battery slurry, improve the dispersion state of the battery slurry, then improve the adhesive force of cathode plates. LiFePO4 with 3% KB adding has the best rate performances with a discharge capacity of 141mAh/g at 1C rate.
  • Preparation and Research of PLLA Blend with High Transparence and Heat Resistance
    . 2011, 42(05): 35-0.
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    ABSTRACT : Poly(L-lactide) (PLLA) was melt blended with poly(methyl methacrylate) PMMA. In this way, transparent blend was produced. It is found that PLLA/PMMA blend has high miscibility in the amorphous state because only single Tg is observed in the DSC measurement. The bending strength, impact strength and tensile strength of PLLA/PMMA blends are higher than those of pure PLLA and pure PMMA. Avrami index shows that the adding of PMMA does not change the nucleation and crystal growth mechanism of PLLA. But the crystallization rate of PLLA is lowered. Vicat transition temperature of the blend will increase when the PMMA content rises. Thermal treatment was also used to prepare translucent PLLA/PMMA blend of high heat resistance. Best condition of thermal treatment has been decided.
  • Thermoelectric properties of Ce0.8Fe4-xNixSb12 compounds prepared by MS+SPS technique
    . 2011, 42(05): 36-0.
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    Single-phase skutterudite compounds with highly relative density Ce0.8Fe4-xNixSb12(x=0~0.15) were prepared by combining melt spinning technique with spark plasma sintering. Their phase structure, microstructure and thermoelectric properties were investigated. The result reveals that all samples show p-type conduction. When Fe was substituted by Ni, the electrical properties can be reduced to some extent, but the total thermal conductivity is decreased more evidently due to the reduction of ?c caused by decreased carrier concentration and ? L caused by alloying scattering. The maximum ZT value of ~0.73 is obtained at 800 K for the x=0.05 and x=0.10 samples, which is 18% higher than that of x=0 sample.
  • Microwave Hydrothermal Synthesis of γ-AlOOH and γ-Al2O3 Hierarchically Nanostructured microspheres self-assembled by nanosheets
    ;;;Zhen-Feng ZHU
    . 2011, 42(05): 37-0.
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    Hierarchically nanostructured γ-AlOOH microspheres self-assembled by nanosheets were successfully prepared via microwave hydrothermal method at 160℃ for 30 min, by using AlCl3?6H2O, NaOH as raw materials and cetyltrimethyl ammonium bromide (CTAB) as surfactant, respectively. The morphology-contained γ-Al2O3 can be obtained through the thermal decomposition of γ-AlOOH precursors at 500℃ for 2 h. The as-prepared products were characterized by SEM、TEM、SAED and XRD. Besides, the thermal behavior of decomposing γ-AlOOH precursors synthesized by hydrothermal process was studied through TG-DAT. Finally, both of γ-AlOOH and γ-Al2O3 microspheres were used to adsorb Congo red from water solution. The experimental results shown that hierarchically nanostructured γ-AlOOH microspheres with the diameter about 1 μm self-assembled by nanosheets with the thickness ~30 nm can be obtained by using the microwave hydrothermal method. The morphology-contained γ-AlOOH microspheres were obtained after a thermal decomposition process, and nanometer-size holes appear on the surface of the nanosheets. Both of γ-AlOOH and γ-Al2O3 microspheres are powerful in the removal of Congo red pollutant from waste water.
  • Rapid Synthesis of B-doped Si80Ge20 alloy and their thermoelectric properties
    Wen-Hui LUO;;;;Tang Xinfeng
    . 2011, 42(05): 38-0.
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    p-type polycrystalline Si8oGe20Bx(x=0.5, 1,1.5, 2) alloy were prepared by arc melting and ball milling followed by spark plasma sintering (SPS) method. The phase composition and the microstructure of the bulk were investigated, and their thermoelectric properties were measured form room terperature to 1000 K. XRD patterns show that all samples are single phase. No obvious segregation phenomenon was found in the bulks form the FESEM and EDS results. The carrier concentration increased significantly by B-addition. The electrical conductivity was continuously enhanced with increasing B content, while the Seebeck coefficient was decreased. The lattice thermal conductivity was significantly decreased beacause the phonon scattering was increased by B-doped. The maximum ZT value of 0.78 is obtained at 1000 K for the sample with x = 1.
  • The Interaction Mechanism of Dicarboxylic Acids and Electrically Conductive Adhesives
    Xiang-Yan CHEN;;Fei XIAO
    . 2011, 42(05): 39-0.
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    Abstract：The conductivity of electrically conductive adhesives (ECAs) was improved by surface functionalizing silver flakes with dicarboxylic acids, or by directly adding dicarboxylic acids into ECA. The resistivity of ECAs was among 2~5×10-5Ω?cm. Raman spectroscopy and X-ray photoelectron spectroscopy reveal that the pentanedioic acid is chemically adsorbed onto the silver flake surface with monodentate bond. The differential scanning calorimetry (DSC) results show that pentanedioic acid can promote the curing reaction of epoxy in both processes, and thus increase conductivity of ECAs.
  • Synthesis ZnSe:Fe Nanocrystals via Liquid-Solid-Solution Method and Their Optical Characterization
    Ling-Yun LIU
    . 2011, 42(05): 40-0.
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    ZnSe:Fe nanocrystals(NCs) were synthesized by a simple liquid-solid-solution method. The crystalline and optical properties of ZnSe:Fe NCs were characterized by X-ray diffraction,transmission electron microscopy, photoluminescence spectroscopy, UV-visible spectrometer and FT-IR spectrometer, respectively. The influence of doping on the optical properties of ZnSe:Fe NCs was investigated. It was found that the ZnSe:Fe NCs are highly crystalline and show zinc blende structure with an average particle size of about 3.5nm-4.5nm. Compared to the pure ZnSe NCs, the ZnSe:Fe NCs exhibited significantly enhanced luminescence properties. The emission band and the intensity of PL emission were all changed when the doping concentration altered. The absorption peak of sample is observed at around 410nm which is blue shifted from the corresponding bulk value, it may be due to quantum size effect. The optical band gap of ZnSe:Fe was calculated using theTauc relation,it was 3.4eV.
  • Influence of melt spinning on hydrogen storage kinetics of nanocrystalline/amorphous Mg2Ni-type alloy
    Yanghuan Zhang ;;;;
    . 2011, 42(05): 41-0.
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    The Mg2Ni-type alloys with nominal compositions of Mg2Ni1-xCox (x = 0, 0.1, 0.2, 0.3, 0.4) are fabricated by melt-spinning technique. The as-spun alloy ribbons, which have a continuous length, a thickness of about 30 μm and a width of about 25 mm, are obtained. The structures of the as-spun alloy ribbons are characterized by XRD and TEM. The hydrogen absorption and desorption kinetics of the alloys were measured by an automatically controlled Sieverts apparatus. The electrochemical hydrogen storage kinetics of the as-spun alloy ribbons are tested by an automatic galvanostatic system. The electrochemical impedance spectrums (EIS) and the Tafel polarization curves are plotted by an electrochemical workstation. The hydrogen diffusion coefficients in the alloys are calculated by virtue of potential-step method. The results show that the as-spun alloys have nanocrystalline/amorphous structure, and the amorphization degree of the alloys visibly increases with rising spinning rate. Furthermore, the melt spinning treatment significantly improves the hydrogen storage kinetics of the alloys. As the spinning rate increases from 0 (As-cast is defined as the spinning rate of 0 m/s) 30 m/s, the hydrogen absorption saturation ratio ( ) of the (x=0.3) alloy increases from 81.9 to94.7%, the hydrogen desorption ratio ( ) from 34.9 to 57.3%, the hydrogen diffusion coefficient (D) from 7.24×10?12 to 3.66×10?11cm2/s and the limiting current density (IL) from 121.7 to 811.6 mA/g, respectively.
  • Effect of thermomechanical treatments on properties of dilute CuCr alloys
    Cheng-Dong XIA
    . 2011, 42(05): 42-0.
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    Two different thermomechanical treatments (TMT) and their effects on the properties of Cu-0.4Cr alloys were investigated. The alloys were characterized using the measurement of Vickers and electrical conductivity to optimize the process which was suitable for commercial producing the alloys with best combination of strength and conductivity. The microhardness and electrical conductivity of the alloys after online hot rolling-quenching and cold rolling with 60% reduction and then aging 450℃ for 30min reached 156HV, 86.4%IACS, respectively, and the process was suitable for commercial production; Alloys which were prepared by solution treatment – cold rolling with 80% reduction – aging 450℃ for 30min obtained the excellent properties with microhardness and conductivity reached 176HV, 80.2%IACS, respectively, but it was unpractical to carry out on the production line. Analysis of the results indicated the prepared Cu-Cr alloys were sensitive to aging temperature and aging time, and easily inclined towards overaging, and the higher aging temperature and cold rolling reduction, the more distinctly overaging, so it was difficult to control the production. Micro-alloying maybe a worth study to suppress the softening of Cu-Cr alloy.
  • Structure and Electrochemical properties of LiGdxMn2-xO4（0≤x≤0.1）materials
    huai-bing SUN;;Y.G. Chen
    . 2011, 42(05): 43-0.
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    Gd3+-doping lithium manganese oxide LiGdxMn2-xO4 (x=0, 0.01, 0.05, 0.1) materials were synthesized by solid-state sintering method and their structure and electrochemical performance were investigated in this paper. The part substitution of rare-earth element Gd3+ for Mn in LiMn2O4 was found to decrease the lattice parameter, unit cell volume, Mn-Mn and Mn-O bond spacings, Mn3+/Mn4+ ratio, which result in the improvement of structure stability of LiMn2O4. When x?0.05, Gd2O3 second phase appears. Cyclic voltammongram (CV) and Electrochemical impedance spectroscopy (EIS) analyses indicated that Gd3+-doping could reduce the cathode & anode polarization and the charge transfer resistance during the electrochemical process, and thus improve the electrochemical reversibility and kinetics of LiMn2O4 electrode material. Electrochemical measurements showed that the cyclability, high-temperature and high-rate performances of LiMn2O4 electrode materials were significantly improved with increasing Gd3+ addition.
  • Effect of Different Graft Ratio on the Properties of PVDF-g-PNIPAAm Temperature Sensitive Membranes
    ; ;zhao yi ping
    . 2011, 42(05): 44-0.
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    The poly(vinylidene fluoride)-g-poly(N-isopropylacrylamide) (PVDF-g- PNIPAAm) copolymers with different graft ratio were synthesized via grafting NIPAAm onto PVDF substrate using atom transfer radical polymerization (ATRP) and radical polymerization of alkali treated PVDF, respectively. The graft copolymers were cast by phase inversion into PVDF-g-PNIPAAm temperature sensitive membranes. The chemical structures of the graft copolymers and membranes were characterized, respectively, by 1H-NMR and X-ray photoelectron spectroscopy (XPS). The pore structure of the copolymer membranes were measured using mercury injection apparatus. In comparison with ATRP method, the graft ratio of the copolymer synthesized by alkali treatment method was higher. The effect of temperature on the rejection ratio of bovine serum albumen (BSA) was investigated. The results showed that the temperature sensitivity of the copolymer membranes was controlled by the graft ratio of PNIPAAm. The temperature sensitivity of the PVDF-g-PNIPAAm membrane prepared by ATRP method was opposite to that of alkali treatment method.
  • Preparation and study of NiO buffer layer for superconducting coated conductor
    . 2011, 42(05): 45-0.
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    A randomly oriented NiO growth is an important problem for the preparation of superconducting coated conductor. A simple and valid method is to prepare textured NiO film on the bare nickel tape. In this paper, NiO film was prepared in air by the surface oxidation epitaxial method. High temperature and short time are in favor of the growth of smooth and densification NiO film. We obtained the smooth and densification NiO film at optimal temperature and for optimal time. The buffer layer of SmBiO3 was fabricated on the NiO film. This provides a potential value of the substrate for preparing superconducting layer.
  • First-principle study on electronic structures of barium zirconate titanate (BZT)
    meng huo
    . 2011, 42(05): 46-0.
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    Using the pseudopotential plane wave method based on density functional theory (DFT), electronic structures of Zr doped BaTiO3 are studied by first principles. The results show that the band gap of pure barium titanate (BTO) is 1.863 eV. As the content of zirconate increases, the total densities of states of barium zirconate titanate (BZT) moves to high level and the band gap gradually increases, therefore the conductivity and dielectric loss decrease.
  • Performance and Structure of LiFePO3.99F0.01/C as Cathode Material for Lithium Ion Battery
    ;;;Yan-xuan WEN
    . 2011, 42(05): 47-0.
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    LiFePO4 has been studied intensively as a potential cathode material for rechargeable Li-ion batteries. However, poor rate performance limits its commercial application. In our work, LiFePO4-xFx/C composite cathode materials were prepared by carbothermal reduction technology to improve its rate performance. The crystalline structure, morphology and electrochemical performances of the samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transfer infrared spectroscopy (FT-IR), charge-discharge experiments, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results showed that doping with F- can reduce the electrochemical polarization and the resistance of charge transfer, and improve lithium ion diffusion rate, which improve the rate capability of cathode material. Among these composite cathode materials, LiFePO3.99F0.01/C delivered a discharge capacities of 109.9 mAh?g-1 and 110.6 mAh?g-1 after 50 cycles at 5C and exhibited good rate performance.
  • Preparation and characterization and biological functions of collagen from Alaska pollock processing by-products
    Han LIU; ;;;;
    . 2011, 42(05): 48-0.
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    Acid-soluble collagen from the processing waste of Alaska pollock was extracted and characterized. It had a maximum UV absorbance at 230nm while amino acid composition and SDS-PAGE suggested it was type I collagen. FTIR spectra showed the existence of helical arrangements. Hydrolysates were prepared by acid hydrolysis. The average molecular weights of its hydrolysates ranged from 3.2kDa to 53kDa. Functional properties of the collagen have been diversified by hydrolysis. For the collagen polypeptides of higher molecular weight, stimulatory effects on hemostasis and wound healing were found. Besides, clotting time reduction in mice was also revealed. While the molecules of lower molecular weight showed positive effects on scald repair.
  • study on the high-quality WRe thermocouple material and its compensation method
    ;;;;;
    . 2011, 42(05): 49-0.
    Abstract ( ) Knowledge map Save
    In this paper, a high-quality WRe thermocouple material is Prepared and it’s thermo-electric property and compensation method are analyzed, The Distribution of trace elements and Microstructure of WRe thermocouple material were characterized by energy dispersive spectrometer scanning electron microscope (EDS-SEM),X-ray diffraction (XRD),The effect of the distribution of trace elements and microstructure on the thermo-electric property were investigated, and relation of the compensation temperature of WRe thermocouple and the measures temperatures accuracy were analysed. This type of thermocouple material is made into the quick Response WRe thermocouple and it is used to measures temperatures in liquid steel, The result showed that temperature stability of the quick Response WRe thermocouple is ±3℃.
  • The Influence of Additives on Asphalt Combustibility Performance
    Rui-Kun DONG
    . 2011, 42(05): 50-0.
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    The warm mix asphalt modifier is often used to decrease the paving or rolling temperature during the pavement construction in the tunnel or other special environment. But there is little research on whether the warm-mixing modifier affects the asphalt combustibility performance. In this paper, three different additives ADZ, ADW, ADS are selected and blended to different asphalt respectively, and the oxygen indexes are tested through the digital oxygen index meter. The effects of additive on the combustibility performance of asphalt or flame retardant asphalt are discussed. The experimental results indicated that three kinds of additives have no adverse effects on the combustion performance of asphalt, and will not affect the flame retardant properties.
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