15 January 2014, Volume 45 Issue 01

    

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工艺 技术
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  Study of Mesa Etching for InAs/GaSb Superlattice Infrared Detector using ICP System

  Jie GUO

  . 2014, 45(01): 1-0.

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  InAs/GaSb superlattice infrared thin film with pin structure was grown on GaSb substrates by molecular beam epitaxy system. Using inductively coupled plasma (ICP) etching technique and Cl2/Ar etching gas to form the smooth mesa, the influence of time, Cl2 percent and power on the etching rate and morphology were studied. It showed that the etching rate of InAs was lower than that of GaSb and the surface was smooth at Cl2 in the range of 20%～40%. It benefits to form ohm contact and decrease surface leakage current in the photovoltaic detector.
研究 开发
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  Study on bisphenol A imprinted sensor based on the film of gold nanoparticles

  Guang-Chao Zhao

  . 2014, 45(01): 2-0.

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  In this work, the gold nanoparticles (AuNPs) modified molecularly imprinted polymers (MIPs) sensing electrode towards bisphenol A has been made by electrochemical methods and molecular imprinting technique on the surface of the gold electrode substrate. SEM, TEM and electrochemical analysis were employed to characterize the films on electrode. The results show that the electrochemical deposition method can make the gold nanoparticles grow regularly and the obtained film uniform. AuNPs modified Au electrode has a three-dimensional structure on the surface, and part of gold nanoparticles can be found within the mosaic structure in the MIPs, which increases the surface conductivity of the electrode significantly. The signals response to bisphenol A show that the MIP-AuNPs-Au electrode has a 2.63 times higher response compared to the MIPs-Au electrode and its detection limit is 1.47×10-8mol/L in detecting bisphenol A. Besides, the MIPs-AuNPs-Au electrode has a good selectivity towards bisphenol A and favorable stability.
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  Research on Ferro-matrix Composite Reinforced by Al2O3-TiC/TiCN Particles

  LIU Sheng-Ming

  . 2014, 45(01): 3-0.

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  The ferro-matrix composite reinforced by Al2O3-TiC/TiCN particles which was produced by in-Situ synthesis from ilmenite are successfully prepared by hot-pressing process. In this paper, the phase、microstructure and properties are investigated by using XRD、SEM and mechanical testing means. The XRD results show that the TiC / TiCN particles will be oxidized and the intermediate oxide of titanium appears during the sintering process. The properties of synthetic material are excellent, the hightest mechanical property of the material for the flexural strength is 1334 MPa and the Vickers hardness is 802.
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  Preparation of C/SiCw composite and its Electromagnetic absorption properties

  ;;Jin LI;

  . 2014, 45(01): 4-0.

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  C/SiCw composite was prepared through sol-gel and carbon thermal reduction，taking Phenolic resin as a carbon source and TEOS as silica precursor. The components, morphology and electromagnetic absorption properties of the prepared composite were characterized by component analysis, XRD, SEM and electromagnetic parameters determination methods, and the effects of preparation conditions such as catalyst and temperature on structures and properties of the prepared composite were systemally investigated. The results show that C/SiCw-50 composite has an optimal performance for electromagnetic absorbing, which was prepared under 1500 ° C with FeCl3 as catalyst, from the precursor with a carbon-silicon ratio of 3. In the range of 2-18GHz, the maximum reflection loss of C/SiCw-50 composite is -27.2dB, with bandwidth about 4.5GHz corresponding to the reflection loss below -5dB at 6.3-10.8GHz.
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  Electric induced domain switching of PLZT by In-situ XRD measurements

  Ying LIU;

  . 2014, 45(01): 5-0.

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  Abstract: The nominal composition of Pb0.93La0.07(Zr0.52,Ti0.48)O3 ferroelectric ceramics with the average grain size of 1~2μm in tetragonal structure was prepared through a conventional solid-state synthesis route. The in-situ XRD measurements under the applications of different DC electric fields were carried out by employing a self-made electric loading device and a commercial X-ray diffractometer. The percentages of 90° domain reorientation were calculated through the analyses in relative peak intensities of (002) and (200), and compared with those obtained by ex-situ measurements. The behaviors of electric induced domain switching before and after the applications of electric fields were preliminary investigated. It was found that a domains as high as 7% would reorient right after the moment by unloading electric field.
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  Effect of microstructure and solubility of calcium silicate hydrate modified by polyethyleneglycol

  . 2014, 45(01): 6-0.

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  In order to enhance the solubility of calcium silicate hydrate (CSH), this material was modified by polyethyleneglycol (PEG) as pore-generation agent. This study focuses on the effect of molecular weight of PEG on the microstructure and solubility of CSH. The research shows that PEG molecules insert the defect region of oxygen-silicon tetrahedron chain or the layers of CSH. This progress prevents the association of Van Der Waals force among the CSH particles. The residual space caused by the incineration of PEG increased the pore volume and specific surface area of CSH. The pore volume and specific surface area of CSH modified by PEG with molecular weight 2000 was 87.48m2/g and 0.33cm3/g, respectively. And the concentration of Ca2+ was 6.75mg/L. The phosphorus content of sediment after phosphorus recovery could reach 19.05%.
综述 进展
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  Researches on the composition design and phase-boundary building of KNN based lead-free piezoelectric ceramics

  Chao LIU;Fangxu LI; Jian-Guo ZHU

  . 2014, 45(01): 7-0.

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  Potassium sodium niobate (KNN) based lead-free piezoelectric ceramics, which have superior piezoelectric and dielectric properties especially for the compositions near their morphotropic phase boundary (MPB) or polymorphic phase boundary (PPB), have been deeply and widely researched. In this paper, the dependence of the phase-boundary building and composition design for KNN based lead-free piezoelectric ceramics are summarized and the recent progress of the composition design with phase-boundary building and properties’ adjustment are reviewed according to the related reports. The significances of the composition design and phase-boundary building in the field of lead-free piezoelectric ceramics are explained, and the research prospects of the phase-boundary building in lead-free piezoelectric ceramics are also prodicted in this paper.
研究 开发
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  Study of the Segregation and Segregation Structure in an A356 Casting by Local filling Squeezing

  Jiang kaiyan

  . 2014, 45(01): 8-0.

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  Circular spots take place on the surface near local fillng squeezing puncher pin of an A356 aluminum alloy squeeze casting Air Cylinder. Corresponds to one filling squeezing and the twice fillng squeezing monocyclic and bicyclic spots, the circle spot diameter are 33mm and 61mm, its width 0.6mm-2mm.The silicon content at circle spot exceeds 29% above the average of the alloy, about 8.5 times the average relative content of the eutectic in alloy. Local fillng squeezing in the area of solid-liquid two-phase result in the liquid separating from solid , liquid flow direction opposite to the direction of extrusion, then resulting component segregation and segregation microstructure. Segregation microstructure with normal matrix microstructure to maintain the integrity of the bonding, no defects such as cracks, the Air Cylinder part still meet use airtight and pressure resistance requirements.
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  Fatigue wear test study of a new artificial mechanical heart valve

  Liang-Liang WU;;;;

  . 2014, 45(01): 9-0.

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  In order to test the fatigue wear characteristics of the new valve, TH-2200 fatigue life tester was used for an artificial bileaflet heart valves with polyformaldehyde(POM) leaflets to have accelerated fatigue tests, surface topography was detected by scanning electron microscopy (SEM). After the 4×108 times fatigue tests, it was shown that no significant wear on the valve ring, valve leaflets rotated flexibility and the heart valves worked well, but a small POM pit adhesion was found in the valve ring part of the pivot position, POM particles size was about 0.1-1μm, leaflets total wear rate was 0.681%. Although the new valve fatigue test showed that the valve had reasonable structural design, which could meet the requirements of national standard fatigue life, but the valve still need to surface treatment, to improve the wear resistance of the valve leaflets.
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  Synthesis and characterization of amine-immobilized ionic liquid for capture of CO2

  ;; ;;

  . 2014, 45(01): 10-0.

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  A new amino-functionalized ionic liquid immobilized on silica was prepared by the organic-inorganic grafting method. Its structure and composition were confirmed by element analysis and nuclear magnetic resonance. The product presents a high specific surface area and excellent thermal stability in terms of the results of thermogravimetric analysis and BET. The absorbing contents of CO2 in the ionic liquid were measured as 0.041mmol/g,0.068mmol/g, 0.189mmol/g and 0.405mmol/g in the corresponding pressure of atmospheric pressure, 0.4MPa, 0.7MPa and 1.0MPa, respectively. The absorption capacity of the product is perfect. With the increase of adsorption pressure, the adsorption capacity increases rapidly. After recycling use of the product for 5 times, the absorption capacity didn’t decreased significantly.
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  Effect of activation medium on microstructure and CO2 adsorption performance of activated carbon

  Xiang-kun JIAN;;

  . 2014, 45(01): 11-0.

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  Developed microporous activated carbons were prepared from carbonized coal by using steam activation and CO2 activation. The N2 adsorption-desorption isotherms, iodine value, methylene blue value, CO2 adsorption capacity, CO2 desorption value and SEM were applied to characterize the activated carbons. The results show that the main pore of activated carbons distribute in the range of 0.5～1.0 nm by using steam activation and CO2 activation, in the same experiment condition, using CO2 activation are 10 % more the pore content in the range of 0.5～1.0 nm than using steam activation, while the mesopore of activated carbons by using steam and CO2 activation respectively distribute in the range of 2.0～3.0 nm and 2.0～2.5 nm. The methylene blue value, iodine value and CO2 desorption value of activated carbons by using steam activation are higher than activated carbons’ by using CO2 activation, but the CO2 adsorption capacity of activated carbons by using CO2 activation are higher than activated carbons’ by using steam activation.
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  Preparation and thermoelectric properties of K and Al co-doped Bi2Te2.7Se0.3

  Xing-Kai DUAN

  . 2014, 45(01): 13-0.

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  K and Al co-doped Bi2Te2.7Se0.3 thermoelectric materials were synthesized by vacuum melting and hot pressing method. Phase structure and surface morphology were characterized via X-ray diffraction (XRD), scanning electron microscope (SEM). XRD results indicate that all the characteristic peaks of the bulk K0.04Bi1.96-xAlxTe2.7Se0.3 can be indexed into rhombohedral Bi2Te2.7Se0.3. SEM analysis shows that the bulk samples are compact with the laminated structure. Seebeck coefficients of K0.04Bi1.92Al0.04Te2.7Se0.3 alloy are improved. K0.04Bi1.88Al0.08Te2.7Se0.3 and K0.04Bi1.84Al0.12Te2.7Se0.3 samples results in substantial increase in electrical conductivity. Thermal conductivity can be reduced by partial Substituting Bi with K and Al. K and Al co-doping can effectively enhance the thermoelectric figure of merit of Bi2Te2.7Se0.3 alloy from 300 K to 500 K.
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  The lubricating and in situ reconditioning effects of the nano scale attapulgite fiber on carbon steel tribopairs

  Bao-Sen ZHANG ;;;WANG Zhang-Zhong

  . 2014, 45(01): 14-0.

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  A friction geometry modifier was prepared out of nanoscale attapulgite fibers using mechanical ball-milling method. The lubricating and in situ reconditioning effects of the as-prepared modifier on carbon steel tribopairs were evaluated by employing a reciprocating friction and wear tester. The mechanisms for friction and wear reducing and reconditioning effects were discussed based on the characterization of the self-reconditioning layer with scanning electron microscope (SEM), energy dispersive spectroscope (EDS) and nano-indenter. Results show that the nano scale attapulgite fiber has excellent friction and wear reducing performance associated with the match of the applied load and sliding velocity. Under the condition of 50N and 1.0m/s, the corresponding friction coefficient and mass wear rate reach the lowest value, and decrease by 58% and 81%, respectively, compared to those of the base oil. An induced uniform and continuous multi-apertured self-reconditioning layer has formed on the friction surface with a thickness about 1.52μm due to the complex physicochemical interactions between the fibers and contact surface. The layer shows smooth and possesses nano-mechanical properties, which is responsible for the significant decrease in friction and wear, mainly with Fe, C, O ,Si and small content of Mg and Al.
工艺 技术
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  Preparation of PNR/NiHCF/CNTs film modified electrode and the electrocatalytic properties for H2O2

  . 2014, 45(01): 15-0.

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  Abstract: Eletroactive composite film with poly(neutral red)/nickel hexacyanoferrate(PNR/NiHCF) on carbon nanotubes(CNTs) modified glassy carbon electrode(GCE) were synthesized by using cyclic voltammetry(CV). The morphologies and structures of the as-prepared PNR/NiHCF/CNTs ?lms were characterized using scanning electron microscopy(SEM) and Fourier transform infrared spectroscopy(FT-IR),respectively. SEM Images showed the three-dimensional porous network composite films with uniform distribution of both PNR and NiHCF nanoparticles along the CNTs. The composite films were applied for H2O2 detection and showed synergy and excellent electrocatalytic activity. The linear range for the detection of H2O2 was 6.25×10-6~3×10-3M with a high sensitivity of 1455.9mAM?1cm?2 and a rapid response(less Than 3s).The detection limit for H2O2 was as low as 1×10-7M(S/N=3). The hybrid ?lm prepared had good stability and reproducibility in the detection of H2O2,and should be useful in practical H2O2 sensors.
研究 开发
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  Preparation and characterization of Fe3O4@TiO2 core-shell magnetic nanomaterials

  . 2014, 45(01): 16-0.

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  Abstract: Core-shell magnetic Fe3O4@TiO2 nanomaterials with different morphplogies have been obtained by combining the sol-gel method and solvothermal method. The monodisperse Fe3O4 core was synthesized by solvothermal reaction, and the TiO2 shell was derived using solvothermal reaction and sol-gel method with tetrabutyl titanate as the precursor. The morphology, structure and magnetic properties of Fe3O4@TiO2 nanomaterials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM). The results showed that Fe3O4 nanoparticles were coated by TiO2, and Fe3O4@TiO2 exhibited high degree of crystallinity, regular crystalline morphologies and excellent magnetism. These integrated features would make the Fe3O4@TiO2 materials have attractive applications in areas of environmental purification, biomedical field, energy conversion and storage. In addition, the formation mechanism of TiO2 shell was also proposed.
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  Improving Photocatalytic Performance of ZnIn2S4 Loaded with Cocatalysts

  wenhui yuan ;;

  . 2014, 45(01): 17-0.

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  ZnIn2S4 was synthesized by hydrothermal method. PdS、SrS、Pt、Ru were respectively loaded onto ZnIn2S4 as cocatalyst. PdS and noble metal co-loaded photocatalyst were also prepared. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible diffuse reflectance spectroscopy (UV–vis). The results indicated that all the samples were of the same crystalloid structures and optical properties. The formation of PdS could be evidenced by XPS analysis results. PdS and noble metal co-loaded can interact with each other and cooperate on improving the photocatalytic activity. The highest photocatalytic activity was observed on ZnIn2S4 co-loaded with 0.5wt% PdS and 0.5wt% Pt, with the rate of hydrogen evolution to be 1.79mmol·h-1, which was ca. 19 times more than that of ZnIn2S4. The possible coordinated mechanism was discussed.
工艺 技术
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  The preparation of nanometer tellurium powder with liquid phase reduction method under the condition of different solvents

  ;;

  . 2014, 45(01): 18-0.

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  At room temperature and pressure, the nano-tellurium powder was prepared by hydrazine hydrate via liquid-phase reduction with the elemental tellurium dissolved in acid solution. With X-ray diffraction (XRD), scanning electron microscopy (SEM), different solution system and dispersants on the tellurium powder structure and morphology were studied and the effect of Cl- during telluride crystal formation was analyzed. The results showed that: in nitric acid solution system, tellurium reduced by hydrazine synthesis was nano-particulate. The grain size was about 20 ~ 50nm; Cl-exist in a mixed acid system, due to Cl- with a release agent coordination role and the role of the tellurium or prismatic nanorods were large grain size of about 5 ~ 10μm, a width of 300 ~ 500nm. A high concentration of Cl- can make tellurium nucleation point increase in the number of small grains more uniform nanorods, the size is about 200 ~ 300nm, a width of 10 ~ 20nm; Cl- system in the dispersant is added PVP when tellurium than a single grain shape uniform, nanorods, the grain size of about 0.5 ~ 3μm, diameter of 20 ~ 50nm.
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  Ultrasonic-assisted preparation of well-dispersed magnesium hydroxide with spherically flower shape

  Peng QIAN;;钱鹏

  . 2014, 45(01): 19-0.

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  In this paper, well-dispersed magnesium hydroxide (MH) with spherically flower shape was synthesized through one-step precipitation process, in which magnesium sulfate solution (MgSO4) and ammonia water (NH4OH) were simultaneously added into an organic phase with the aid of ultrasonic radiation. The polarity,morphology and thermal property of the products are analyzed in terms of XRD, SEM, FT-IR, TG, DSC respectively. In addition, sedimentation experiments were carried out in order to verify the dispersibility of the products. Besides, it is also concluded that the decrease of reaction temperature would lead to an improvement of morphology in uniformity and disperibility.
研究 开发
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  Conductive properties of conductive titanium dioxide / PA fiber

  ;;;

  . 2014, 45(01): 20-0.

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  The surface of conductive titanium dioxide was treated by solution of sodium, then it was mixed with PA . Finally the conductive fiber was prepared through melt spinning.The conductive titanium oxide can be well dispersed in the PA matrix and PA matrix’s compatibility was well after being treated. The conductive properties were studied, along with the result that it belonged to tunnel conductive when the ratio of the conductive titanium oxide is lower than 7% and tunnel conductive and ohmic conductive combination of conductive when its concentration between 10% and 13%, while it was the ohmic conductive when the doping is greater than 13%
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  Effects of hexametaphosphate on rapid growth and optical properties of KDP crystals

  Sheng-Jun ZHU; ;;;;;;

  . 2014, 45(01): 21-0.

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  By altering the concentration of hexametaphosphate in the growth solution, a series of KDP crystals was grown by “point seed” rapid growth method at the growth rates about 20mm/day. Effects of hexametaphosphate on the rapid growth and optical properties of these as-grown KDP crystals were investigated, comparing with those crystals grown by the traditional temperature lowering method. The results indicated that, in the presence of a small amount of hexametaphosphate, the stability of growth solution was decreased greatly and the growth of crystal faces was inhibited significantly. At the same time, many macro defects occurred easily such as mother liquid inclusions, parasite crystals and crushing cracks. Furthermore, due to the presence of hexametaphosphate, the light scattering in KDP crystals was aggravated markedly and the laser damage threshold was decreased greatly. The crystal grown by "point seed" rapid growth was affected more severely than that by traditional growth method, in the same concentration of hexametaphosphate. The impact mechanism was also analyzed combining with the structure of KDP crystals and chemical characteristics of hexametaphosphate molecules.
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  Adsorption Kinetic Studies of Cu2+ onto carboxymethyl cellulose gauze from Aqueous Solution

  Xi-Hui ZHAO;

  . 2014, 45(01): 22-0.

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  Carboxymethyl cellulose gauze (CMC gauze) was prepared with cotton gauze. The adsorption behavior of Cu2+ on CMC gauze was studied. The adsorption mechanisms were investigated with three different kinds of kinetic models (Lagergren’s pseudo-first-order, Ho’s pseudo-second-order equations and intra-particle diffusion mode1)．The results indicated that the experimental data of the Cu2+ adsorption on CMC gauze could be well described by the Ho’s pseudo-second-order model, the correlation coefficients R2 all reached 0.99. The adsorption process is a complex and heterogeneous chemical adsorption process, the rate were controlled by Membrane diffusion and intra-partiele diffusion process．
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  Numerical Simulation of thermocapillary convection in Detached Solidification

  Gong Huan

  . 2014, 45(01): 23-0.

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  Abstract: A numerical study about heat and momentum transfers in the melt was proformed to clarify the effect of cusp magnetic field on the melt thermocapillary convection in detached solidification by the method of the finite-difference method. During the calculation the melt was considered to be an incompressible Newtonian fluid，the ratio of height and radius and the width of gap were 1 and 0.1, respectively. The process of crystal growth was simulated for Ha=0, 45, 90 and 135 under different Ma numbers. The results indicated that the cusp magnetic field can effectively suppress the flow in the melt, and the inhibition effect was enhanced with the increase of magnetic field strength.
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  Collagen Fiber as a Template for Mesorporous TiO2 and Lax/TiO2 Nano-fibers: Synthesis, Characterization and Photocatalytic Activities

  . 2014, 45(01): 24-0.

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  Mesorporous TiO2 and Lax/TiO2 nano-fiber were prepared by loading Titanium (Ti4+), or Titanium (Ti4+) and Lanthanum (La3+) on collagen fiber template, respectively, and then heat treated. The physicochemical properties of these nano-?bers were fully characterized by means of ?eld emission scanning electron microscopy (FESEM), N2 adsorption-desorption, X-ray diffraction (XRD), UV-vis absorption spectra and photoluminescence spectra (PL). It was found that the fibrous morphology of collagen fiber was well preserved in the TiO2 and La0.02/TiO2 nano-?bers. The N2 adsorption-desorption isotherms of TiO2 and Lax/TiO2 nano-?bers were the typical type IV, which associated with the characteristics of mesoporous materials. XRD analysis showed that La3+ doped into TiO2 has a significant influence on crystal size of TiO2. Compared with Degussa P25, the TiO2 and Lax/TiO2 (x≤0.02) nano-?bers showed a red-shift in their UV-vis absorption spectra, and their PL spectra intensity also exhibited a significant decrease. By using the photocatalytic degradation of malachite green (MG) as a model reaction, the photocatalytic activity of the as-prepared TiO2 and Lax/TiO2 nan-o?bers were evaluated. Mesorporous TiO2 and Lax/TiO2 nano-?bers exhibited much higher photocatalytic activities than Degussa P25 under visible light and UV light irradiation. In addition, Lax/TiO2 nano-fibers showed remarkably improved visible light catalytic efficiency than that of un-doped TiO2 nano-fibers.
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  Synthesis and rare earth doped of CdSe and CdSe/ZnS QDs

  XUE FEI;

  . 2014, 45(01): 25-0.

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  CdSe,CdSe/ZnS and Eu doped QDs were synthesized in LSS system. The QDs were characterized by TEM, XRD , PL and EDX. The TEM results show that the QDs have uniform size and morphology . And the results of XRD show CdSe/ZnS QDs belong to hexagonal crystal system . The PL of the samples prove that the CdSe QDs coated with suitable thickness ZnS have a remarkable rise in Luminous efficiency and the FWHM(the full width half maximum) . And we analyzed this results. The CdSe QDs doped with Eu have a new emission peak.in red area, while the CdSe(Eu)/ZnS QDs do not. We also clarified the causes of this phenomenon .
工艺 技术
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  Study on the microstructure and electrical properties of (Ba1-xCax)(Ti0.85Zr0.15)O3 ceramics prepared by direct reaction sintering method

  ;;;Zhi Jun xu ;;;Guorong Li

  . 2014, 45(01): 26-0.

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  (Ba1-xCax)(Ti0.85Zr0.15)O3 (x=0-0.15) lead-free piezoceramics were prepared by direct reaction sintering method. The phase structure, microstructure, density and electrical properties of the ceramics with different Ca contents were analyzed. The ceramics prepared by direct reaction sintering method possessed pure perovskite phase structure. The ceramics showed compact microstructure and large diameter shrinkage. The Curie temperatures of the samples slightly decreased for all the samples. The piezoelectric constant d33 increased gradually with increasing the Ca content. When x=0.15 the sample possessed largest piezoelectric constant of 208pC/N.
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  One pot synthesis of hypercrosslinked adsorption resin with hierarchical pore structure

  Bao-Juan DOU

  . 2014, 45(01): 28-0.

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  Hypercrosslinked adsorption resins were synthesized with Friedel-Crafts reaction of 4, 4’-bis(chloromethyl)-1,10-biphenyl in mixed solvent by using one pot synthesis. The resultant adsorption resins exhibit hierarchical pore structure, adjustable pore size, super high pore volume（2.53 cm3g-1）and surface area（1592 m2g-1）. It was found that the n-hexane in mixed solvent can used as mesoporous template, and the pore size of the adsorption resin can be effectively adjusted by changing the mixing ratio.
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  Research on the enhanced magnetoresistive response in magnetic-annealed La0.7Sr0.3MnO3

  ;;Dun-Hui WANG

  . 2014, 45(01): 29-0.

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  Polycrystalline perovskite La0.7Sr0.3MnO3 was annealed under magnetic field in order to increase the low-field magnetoresistance effect. The experimental results show that the magnetic annealing would not affect the magnetic moments but remarkably change the magnetic anisotropy of the sample. Compared with the perovskite without magnetic annealing, the magnetic-annealed La0.7Sr0.3MnO3 exhibits large magnetoresistance effect, which can be more obviously observed in low magnetic field. At room temperature, a 140% enhancement of magnetoresistance response at 0.1T was observed in the magnetic-annealed sample, which can be explained with the mechanism of spin-polarized intergrain tunneling.
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  Preparation and application in crystalline silicon solar cell grid of Ni/Cu films by light-induced plating

  ;;;

  . 2014, 45(01): 31-0.

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  Abstract: Nickel films and copper films were fabricated by the method of light-induced plating (LIP), and the influence of some technological factors (deposition temperature , deposition time ect.) on films was studied. To characterize the composition, morphology, resistivity and ununiformity of films, X-ray Diffraction(XRD), Scanning Electron Microscopy(SEM) and Four-probe Tester are used. The results indicates that the copper film’s resistivity is 1.87×10-8 Ω?m and the ununiformity is 2.64%. What’s more, in this paper, Ni/Cu films deposition technique is also introduced in developing the crystalline silicon solar cell. Then the electrical parameters of solar cell were investigated by measuring light I-V solar cell measurements, and FFs is 77.8%.
研究 开发
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  First-principles study on electronic structures and optical properties of Na doping Zincblende ZnS system

  Yuan-Peng XIONG

  . 2014, 45(01): 33-0.

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  The crystal structures, electronic structures and optical properties of Na doping Zincblende (ZnS_B3) system (Zn（1-x）NaxS (x=0, 0.0625, 0.125)) were calculated by using first-principles calculation based on the density functional theory (DFT) within the framework of generalized gradient approximation (GGA). The equilibrium lattice constant, electronic structure including the density of state and band structure of Zn（1-x）NaxS (x=0, 0.0625, 0.125) were discussed in detail. The effects of the electron configuration around Fermi level on optical properties of Na doped-ZnS materials were analysized theoretically. The calculated results reveal that Na doping plays an important role on the optical properties of ZnS_B3, The Na2S doped-ZnS materials show good comprehensive optical properties when the doping concentration of Na+ ion is at 6.25at.%. while the concentration of effective negative charge increases when the doping concentration of Na+ ion is at 12.50at.%, and the S_3p electron states cross the Fermi-level and transit to high energy level. New dielectric peak present in infrared spectra with low energy level and increase the light absorption coefficient, thus decrease the transmission coefficient of ZnS materials. Present calculated results agree considerably with the experiment results in available literatures.