30 May 2015, Volume 46 Issue 10

    

• Select all
  |

工艺 技术
• Select
  The Preparation and Morphology Study of PS-b-PNIPAAm Porous Thin Film

  Zhan LI;;;;Xia FENG

  . 2015, 46(10): 1-0.

  Abstract ( ) Knowledge map Save

  The amphiphilic PS-b-PNIPAAm block copolymer（BCP）was dissolved in tetrahydrofuran to obtain 2wt% solution and the nascent BCP thin films were fabricated by spin-coating. Subsequently, the thin films were annealed in ethanol vapor with different time. The effect of annealing time on microstructure of thin films was discussed. The results indicated that the extension of annealing time resulted in the obvious micro-phase separation of film surface and uniformly distribution of micropores. The film annealed by ethanol was then swelled in pure water or ethanol, respectively. The nanoporous thin films were prepared by swelling-induced pore-making method. The effect caused by swelling time, swelling temperature and solvent on microstructure of thin films was discussed. It is found that the elevation of swelling temperature and increase of swelling time contributed to the formation of microporous structures. Also, the pore-forming ability of ethanol was stronger than that of water in the swelling process.
研究 开发
• Select
  Synthesis of needle-like ZnO nanorods films and the Photoluminescence

  Yu-Wen LU; ;LI LAI QIANG;;

  . 2015, 46(10): 2-0.

  Abstract ( ) Knowledge map Save

  Assisted by NaOH, we synthesized needle-like ZnO films by drip method on Si substrate. The starting materials are commercial zinc powders prepared by vibration milling at room temperature and successive ultrasonic treatment. And we analyzed the phase structure, morphology, and photoluminescence (PL) performance of the films and studied the effect of the concentration of NaOH, milling time of Zn and the type of substrate on the growth of needle-like ZnO nanostructures. We also explored the growth mechanism of the nanostructures. The results show that the best conditions to synthesize needle-like ZnO are: concentration of NaOH is 0.036M, milling time of Zn is 1h and the substrate is Silicon with (111) orientation. The PL spectra demonstrate that ZnO films have excellent optical property. Our results may provide references for the development of nano-optoelectronic devices.
工艺 技术
• Select
  Preparation of supported TiO2 ultrafiltration membranes

  Yue Zhang

  . 2015, 46(10): 3-0.

  Abstract ( ) Knowledge map Save

  TiO2 colloidal sol was prepared by sol-gel method with titanium tetra-isopropoxide as raw material. TiO2 ultrafiltration membranes were prepared using Al2O3 microfiltration membrane of 100 nm pore size as support. Effects of additive contents in dipping sols, coating times and coating time on the integrity of TiO2 ultrafiltration membranes were investigated. It is indicated that defects in TiO2 ultrafiltration membranes can be deliminated by adjusting additive contents, coating times and coating time. Additive content in sol has no effects on the phase of TiO2 ultrafiltration membranes. TiO2 ultrafiltration membranes without cracks and pinholes can be obtained from TiO2 sol with a mass ratio mTiO2: mPVA: mHPC of 8:2:2 by coating for 10 -15 s twice. TiO2 layer thickness is about 1 μm , the pore size distributes in the range of 3 - 8 nm, and the porosity is 42%.
• Select
  Preparation, characterization and photocatalytic activity of N doped TiO2 by nodic oxidation combination with chemical reaction release N2

  Ying-Cao XU;Hong YOU

  . 2015, 46(10): 4-0.

  Abstract ( ) Knowledge map Save

  Abstract: N doping TiO2 was prepared by one step method of anodic oxidation combined with reaction of urea with sodium nitrite under acidic conditions to release nitrogen，anatase N-TiO2 were obtained upon calcination at temperature of 45℃ over four hours. The surface morphology, structure and elements composition was characterized by scanning electron microscope(SEM), energy dispersive spectrometry(EDS), x-ray diffraction(XRD) and X-ray photoelectron spectroscopy(XPS). Photocatalytic activity was characterized by degradation of methyl orange. The result showed that the diameters of the as-prepeared TiO2 and N-TiO2 were about 120nm and 80nm. XRD crystal structure analysis showed there were no changes of anatase phase in the process of N-doped TiO2, but 101 crystal plane peak was significantly enhanced. XPS detected the N atom percentage content of 5.60%. The photocatalytic degradation of methyl orange indicated N-doped TiO2 has higher photocatalytic activity than undoped.
• Select
  Preparation of the modified nanostuctural γ-Al2O3 particles

  Meng CHEN;

  . 2015, 46(10): 5-0.

  Abstract ( ) Knowledge map Save

  Mesoporous nanostuctural γ-Al2O3 was prepared from aluminum nanoparticles with sucrose, Zn powder grinded and Ag + respectively as auxiliary agent by precipitation with the aid of ultrasonic dispersion, drying, calcination. Textural Properties of the modification γ-Al2O3 was explored. The γ-Al2O3 were characterized by XRD, SEM and BET. The result indicated that, a novel and simple method using sucrose Zn powder grinded and Ag + as assistant agent was developed to prepare γ-Al2O3 with high surface area and narrow pore size distribution.
• Select
  Optimization the process parameters of YW2 cemented carbide tool modified by high current pulsed electron beam with response surface method

  Chang-Sheng LOU

  . 2015, 46(10): 6-0.

  Abstract ( ) Knowledge map Save

  The YW2 cemented carbide tools were surface modified by high current pulsed electron beam irradiation. An experiment program with three factors and three levels was designed by using central composite method of Box-Behnken. The effects of accelerate voltage, current, pulse number on the microhardness and roughness of YW2 carbide tools were optimized with response surface methodology. The results show that the optimal parameters are following: accelerate voltage of 10kV, current of 180A and pulse number of 45 times. Compared with the untreated tool, the irradiated YW2 tool under optimal condition has higher microharness and lower roughness. The cutting performance of the irradiated YW2 tool under optimal condition has improved through the cutting tests of titanium alloy.
• Select
  Preparation of Co-N-C and Co-Ti-N-C by Thermal Conversion Using Urea and Their Oxygen Reduction Activity and Stability

  ;Sheng-zhou CHEN ;;

  . 2015, 46(10): 7-0.

  Abstract ( ) Knowledge map Save

  Abstract: In this work，a proton exchange membrane fuel cell (PEMFC) oxygen reduction catalyst Co–N–C and Co–Ti–N–C was prepared by thermal conversion using urea as nitrogen precursor. The oxygen reduction performance and stability of catalyst Co–N–C and Co–Ti–N–C was researched with different urea/Co molar ratios(R)，different calcination temperature and different titanium content. Co–N–C and Co–Ti–N–C were characterized by elemental analysis，thermal gravimetric，X–ray diffraction and X–ray photoemission spectroscopy，and the structure of the oxygen reduction active center was researched. The results showed that the best oxygen reduction performance of the catalyst was in the heat treatment temperature 800℃，urea/Co molar ratios R=12，the peak potential (Ep,c) reached 0.142V (vs.SCE). After soaking for three days in the 353K sulfuric acid solution，the content of the catalyst active center Co4N was increased， Ep,c was moved to 0.445V. The doping of titanium didn’t change the structure of the oxygen reduction active center ，but obviously improved the stability of the catalyst in the acid medium.
• Select
  The Preparation and Properties of Waterborne Polyurethane Containing Epoxy group as Paper Sizing Agent

  ;

  . 2015, 46(10): 8-0.

  Abstract ( ) Knowledge map Save

  A kind of waterborne polyurethane containing epoxy group was successfully prepared by the reaction of :isophorone diisocyanate (IPDI), poly-caprolactone diol (PCL1000), triethylamine(TEA), 2,2-Bis(hydroxymethyl)propionic acid(DMPA) and 1-propanetriol glycidyl ether as the main raw materials. The structure and particle size distribution of waterborne polyurethane were characterized by Fourier transform infrared spectroscopy (FT-IR) and Nano-ZS particle sizer. The FT-IR confirmed that the epoxy group had been introduced into the chain of the WPU. Moreover, the applied properties of the paper were measured as follows when the dosage of the sizing agent was 3%: paper tensile strength was 51.75 N.m.g-1, the sizing value of paper was 35.5s and folding endurance was 38 times.
综述 进展
• Select
  Research status in structure characteristics and hydrogen storage features of superlattice R-Mg-Ni-based alloys

  Zi-Liang CHEN ;

  . 2015, 46(10): 9-0.

  Abstract ( ) Knowledge map Save

  R-Mg-Ni-based (R = rare earth elements，Ca element) superlattice alloys，which are made up of Laves-type A2B4 and CaCu5-type AB5 cells stacked along the c axis，possess the controllable kinetic/thermodynamics properties as well as the high hydrogen storage capacity and good reversibility，so they are considered as the most ideal negative materials for new generation Ni/MH battery．The present situation of research of structure characteristics and hydrogen storage features of R-Mg-Ni-based superlattice alloys are reviewed．Especially，this paper focuses on describing the relationship among the structure，Mg element and hydrogenation behavior of R-Mg-Ni-based superlattice alloys．Finally，the key issues related to the hydrogen storage mechanism which needed to be solved in future were further pointed out．
• Select
  The phase transition and applications of age hardening copper-titanium alloys

  Ying-Hui WEI

  . 2015, 46(10): 10-0.

  Abstract ( ) Knowledge map Save

  Copper-titanium alloys are a kind of age hardening alloys with high strength and good electrical conductivity performance. The phase transition process of copper-titanium alloys was illustrated in detail in this paper and the research status of copper-titanium alloys were described,that is,both aging in hydrogen atmosphere and prior-deformation combined with aging treatment can improve the performance ,such as electrical conductivity and strength. It is pointed out that the influence of grain boundary on performance and the effect of plastic deformation on phase transition are still not clear. Prior-deformation combined with aging treatment will be an attractive area of research in the future.
研究 开发
• Select
  First-principles study of properties in cubic BaTiO3

  ;;Hai-Dou WANG

  . 2015, 46(10): 11-0.

  Abstract ( ) Knowledge map Save

  We investigated the energy characteristics, optical characteristics and thermodynamics factors which influences the material performance of the cubic barium titanate crystal phase structure using the first principle density functional method. The calculation results demonstrate that the cubic phase BaTiO3 is direct semiconductor and the instability derived from the orbital interaction between Ti and O atoms. With the increase of energy, reflex points in the form of random fluctuation and the anisotropy of crystal clear. Enthalpy and heat capacity varies with temperature rise, while free energy fall.
• Select
  Study on Synthesis and Performances of SSS/AA/MPEGAA Polycarboxylates with long side chain

  ZHANG Guang-Hua ;Junfeng ZHU

  . 2015, 46(10): 12-0.

  Abstract ( ) Knowledge map Save

  The esterified macromonmer (MPEGAA) was obtained by esterification of methoxy polyethylene glycol (MPEG) with four kinds of different side chain lengths and acrylic acid. Four kinds of different side chain lengths of polycarboxylate dispersant were preared from esterified macromonmer(MPEGAA), acrylic acid (AA), Sodium p-styrenesulfonate(SSS) as monomers,potassium persulfate(K2S2O8) as initiator and isopropanol as the chain transfer agent. Their structures, thermodynamic performance, the molecular weights and distributions characterized and analyzed by FT-IR, 1H NMR,TG,DSC and gel permeation chromatography (GPC).They were applied to Binchang coal, and apparent viscosity, Zeta potential, the optimum dosage, the maximum slurry concentration and stability of the slurry were investigated. The results show that when the optimum dosage of dispersant is 0.4%, the highest concentration of CWS can reach 68 %, and Zeta potential changes from -11.2 mV to -41.5mV,polycarboxylic dispersant with the length of side chain PC500( n=11), as well as better function on viscosity reduction, dispersal and stabilization of Binchang coal.
• Select
  Properties of Waterborne cationic Acrylic/ Alkyd Coating

  Yi-ding SHEN ;Li-Yuan Guo;

  . 2015, 46(10): 13-0.

  Abstract ( ) Knowledge map Save

  A cationic acrylic/alkyd resin coating was successfully prepared using cationic acrylic/alkyd resin emulsions, titanium dioxide, dispersant, thickener and defoamer as raw materials. The stability, rheological property, thermal property, surface morphology and anti-corrosion property of coating were characterized. The result suggested the stability of coating was best with dispersant dosage of 1.5 wt% and thickener dosage of 0.9 wt%. The result also showed the coating displayed good thixotropic property that favored to storage and bush coating. In addition, the coating could apply to industry under 200℃ with the degradation temperature at 5% weight loss of 215.3℃. The anti-corrosion property test suggested the coating showed corrosion current of 1.076×10-4A/cm2 and exposure in salt spray for 240h. Meanwhile, the film also showed concavoconvex structure with surface roughness of 3.893nm.
• Select
  Synthesis of porous single-crystalline ZnO nanoplates and their sensing properties to indoor air pollutants

  ;;Fan-Li MENG

  . 2015, 46(10): 14-0.

  Abstract ( ) Knowledge map Save

  Porous single crystalline ZnO nanoplates were successfully synthesized through a hydrothermal process followed by annealing of the zinc carbonate hydroxide hydrate precursors.The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy, and high revolution transmission electron microscopy. Furthermore, the ZnO gas sensor was fabricated for the detection of indoor air pollutants containing benzene and formaldehyde. The results demonstrate that the porous single crystalline ZnO nanoplates exhibited both sensitive and stable performance towards indoor air pollutants. The response and recovery time of the as-prepared products also reduced compared with commercial ZnO powders. The sensing mechanism and the influence of porous and single-crystalline structures on sensing properties were discussed.
• Select
  Constitutive model on cyclic transformation included plasticity of super-elastic NiTi alloy

  Qiang-jun Yang;Qian-hua Kan Chao Yu;Shi-yu Dong

  . 2015, 46(10): 15-0.

  Abstract ( ) Knowledge map Save

  To describe quantitative super-elasticity degradation behavior caused by the cyclic transformation induced plasticity of NiTi shape memory alloy, the Graesser model was extended in the frame of general visco-plasticity to consider the difference between austenite and martensite elastic moduli and the nonlinear hardening behavior of martensite. The evolution equations of transformation stress and transformation strain during cyclic transformation were introduced in the proposed model to capture the behavior of the cyclic transformation induced plasticity and the method of parameter calibration was provided. The comparison of experimental and simulated results of NiTi micro-tube subjected to cyclic loading show that the proposed model can predict reasonably the cyclic transformation induced plasticity of NiTi shape memory alloy.
• Select
  Effect of the means of adding MgCl2 on the morphology and particle size distribution of Mg (OH) 2

  . 2015, 46(10): 16-0.

  Abstract ( ) Knowledge map Save

  Magnesium has an important prospect in the field of polymer flame retardant as a kind of halogen-free flame retardant. The nanoscale magnesium hydroxide powder was prepared by Reverse precipitation, the effect of the means of adding MgCl2 was studied on the particle size distribution and reunited state of Mg (OH) 2, and the pyrolysis regularity of Mg (OH) 2 was analyzed by the thermal infrared detection technology. The experimental results show that the means of adding MgCl2 has a significant effect on the distribution and reunited state of Mg(OH)2; the size distribution of Mg(OH)2 was the most homogeneous by four times to add for MgCl2, the proportion of small particles is the largest, and the reunion phenomenon is not easy to happen.
• Select
  Optimization Study on Planar Zero Thermal Expansion Coefficients of the Fiber Orthogonal Cell Laminates

  ;Liu-Shuang

  . 2015, 46(10): 17-0.

  Abstract ( ) Knowledge map Save

  In this paper, the expression of planar thermal expansion coefficients of the fiber orthogonal cell laminates which were called FOCL-CTEs, were deduced based on the classical lamination theory. The effects of fiber volume fraction and the kinds of the epoxy resin on FOCL-CTEs were also studied. It was shown that FOCL-CTEs were independent of ply angles, ply stacking sequences and layers. But when the fiber had greater negative longitudinal thermal expansion coefficient, the FOCL-CTEs would be zero when the fiber volume fraction was adjusted.
• Select
  Numerical Simulation on Wettability of Hydrophobic Surfaces Based on Lattice Boltzmann Method

  Qiao-Gao HUANG

  . 2015, 46(10): 18-0.

  Abstract ( ) Knowledge map Save

  Wettability has an important influence on the dynamic behavior of liquid on a solid surface. The special wettability is the fundamental reason that hydrophobic surfaces are widely applied in drag reduction, noise reduction, antifouling and so on. In this paper, the wettability of hydrophobic surfaces is simulated by lattice Boltzmann method based on Shan-Chen model, and effect of the material property and microcosmic topography on wettability of hydrophobic surfaces is obtained. The simulation results show that in order to make hydrophobic surfaces under Cassie-Baxter wetting state, the height of microcosmic topography must be greater than a critical value. Once hydrophobic surfaces are under Cassie-Baxter wetting state, increasing the height of microcosmic topography does not improve its hydrophobicity. The apparent contact angle of hydrophobic surfaces first increases and then decreases when the gas-liquid interface fraction increases, and there is an optimum gas-liquid interface fraction so that the apparent contact angle is maximized.
• Select
  Tribological Behavior of PEEK and Nano-SiO2 Reinforced PTFE Composites

  Dong Ya YANG

  . 2015, 46(10): 19-0.

  Abstract ( ) Knowledge map Save

  PEEK and Nano-SiO2 particles synergetic filled PTFE composites were prepared by mechanical blending-molding-sintering method. The tribological behavior of composites with different volume fraction of fillers was tested on different test conditions by a MRH-3 block-on-ring friction and wear tester. The transfer film on counterpart GCr15 ring was inspected and anslyzed with scanning electronic microscopy (SEM). The results demonstrated that the lowest friction coefficient was gained when the PTFE composite was filled with only 5% PEEK. The special wear rate of 10%PEEK/PTFE were decreased clearly with filled different contents of nano-SiO2 particles. The special wear rate of the sample with 5% nano-SiO2 and 10%PEEK had the lowest volume wear rete. The load and sliding speed effect significantly on the tribological behavior of nano-SiO2/ PEEK/PTFE composites, but the effect of environmental temperature on the friction coefficient and wear rate of the composite is not obvious.
• Select
  Low-temperature Selective Catalytic Reduction with NH3 Over MnOx-CeO2 Catalysts Supported on Nano Tetragonal-phase Zirconia

  ;Fei YE;;;;

  . 2015, 46(10): 20-0.

  Abstract ( ) Knowledge map Save

  The MnOx-CeO2/t-ZrO2 catalyst was prepared by impregnation with nano t-ZrO2 as the supporter. The influence of active component and reaction temperature on denitration performance of catalyst was investigated. The results showed that denitration efficiency improved as active component increased and reaction temperature rose. The denitration efficiency of 2.5% MnOx-CeO2/t-ZrO2 at 100℃ was 68.1% while 15% MnOx-CeO2/t-ZrO2 was 97.4%. The results of XRD, BET and H2-TPR showed that surface structure of loaded catalyst was good for oxidation-reduction and denigration. NH3-TPD test demonstrated that NH3 was mainly adsorbed at Lewis acid sites on the surface of catalysts and became coordination NH3. Intermediate product NH2NO generated from reactions between coordination NH3 and NO which finally changed into N2 and H2O.
• Select
  Effect of surfactants on the stability of Cu-H2O and ZrO2-H2O nanofluids

  . 2015, 46(10): 21-0.

  Abstract ( ) Knowledge map Save

  Cu-H2O and ZrO2-H2O nanofluids were prepared with surfactants and the impacts of different surfactants, such as sodium dodecyl benzene sulfonate, cetyl trimethyl ammonium bromide and octyl phenyl polyoxyethylene ether, on the stability of Cu-H2O and ZrO2-H2O nanofluids was also studied. Moreover, the interaction energies between various surfactants and the surface of Cu/ ZrO2 particles were calculated with the method of molecular dynamics simulation. It was shown that the addition of surfactants, especially for sodium dodecyl benzene sulfonate, to nanofluids would enhance the stability of the nanofluids to a large extent. Meanwhile, the result was that the adsorption between sodium dodecyl benzene sulfonate molecules and Cu/ZrO2 was strongest. Furthermore, the adsorption behavior between sodium dodecyl benzene sulfonate and Cu particles in the Cu-H2O nanofluid was simulated as well.
• Select
  Preparation and Photocatalytic Properties of La3+、Nd3+ and Non-metallic N Doped TiO2

  . 2015, 46(10): 22-0.

  Abstract ( ) Knowledge map Save

  TiO2, 1%-La/TiO2, 1%-Nd/TiO2 and a series of La3+ and Nd3+doped TiO2 photocatalysts were prepared by sol-gel method. Then, sol-gel method combined with hydrothermal method synthesized multi system of rare earth La, Nd, and nitrogen-doped TiO2 photocatalysts. Their microstructure, spectroscopic properties and ion doped form were characterized by X-ray powder diffraction (XRD), UV-Vis diffuse reflectance spectroscopy techniques, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS). The catalytic activity was tested for the degradation of methyl orange solution. The results showed that, all the samples which prepared in paper were Anatase TiO2 photocatalysts, the doping of La3+ or Nd3+could hinder the growth of TiO2 particle, even, the doping of La3+ with Nd3+ together could more effective hinder the growth of TiO2 particle; Non-metallic nitrogen-doped would broaden the Light response range of TiO2 photocatalyst. At the same time, the activity results indicated that the prepared samples showed superior UV light photocatalytic activity, the sample 1 %-(La:Nd,1:7) N/TiO2 possessed the highest UV-vis photocatalytic activity.
• Select
  Electrochemical performance of LiMnPO4 via co-substitution with Fe and Mg

  Li Ren

  . 2015, 46(10): 23-0.

  Abstract ( ) Knowledge map Save

  LiMn0.7Fe0.3-xMgxPO4/C（x=0.00，0.02, 0.04 , 0.06）composites were synthesized by a solid-state reaction route via Mn-site co-substitution with Fe and Mg, and the crystal structure, morphologies and electrochemical performance of the obtained materials were investigated by X-ray diffraction, scanning electron microscopy and electrochemical measurements. The result shows the obtained samples are contributed to an olivine structure with uniform particle size range of 100nm. Fe and Mg co-substitution could remarkably enhance the electrochemical properties of LiMnPO4/C, and the LiMn0.7Fe0.26Mg0.04PO4/C sample demonstrates the optimum electrochemical performance with initial discharge capacities of 159.7mAh/g,154.3mAh/g,148.2mAh/g,143.9mAh/g and 134.7mAh/g at 0.1C,0.2C,0.5C,1C,2C respectively. Meanwhile, it can retain 94.5% of the initial capacity after 50 cycles at 1C, revealing a stable cycling stability and exhibits an excellent rate capability.
• Select
  Hydrothermal Synthesis of RGO/MnOx Composite and Its Electrochemical Capacitance Properties

  ;

  . 2015, 46(10): 24-0.

  Abstract ( ) Knowledge map Save

  In the present work RGO/MnOx composites were fabracated by a hydrothermal method at different conditions. The crystal structure, chemical state of the elements, and the microstrucuture of the as-obtained samples were chracterized using power X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscopy (FESEM). Moreover, the electrochemical behaviors were evaluated by cyclic voltammogram (CV), galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) in a three electrod system. The test results showed that the specific capacitance of the optimal sample was calculated to be 289.8 F?g?1 in 1 mol?L?1 Na2SO4 electroyte at a current density of 1 A?g?1 with a operating window from 0 to 1 V, and its specific capacitance was 223.9 F?g?1 even at a current rate density of 20 A?g?1. In addition, the capacitance retention ratio of the sample remained 88% after 1000 cycles at a high current density of 5 A?g?1.
• Select
  4-coumaric acid grafted onto xylan catalyzed by laccase for improving its strength properties

  . 2015, 46(10): 25-0.

  Abstract ( ) Knowledge map Save

  Abstract: The reaction of graft copolymerization of xylan with 4-coumaric acid by laccase-catalyzed oxidation, in a way to improve quality of filming of xylan. It was analyzed by infrared FT-IR analysis, 13C-NMR analysis, Py-GC/MS analysis techniques for determining the reaction between xylan and 4-coumaric acid which were chemically connected, and occurred copolymer. By testing the degree of polymerization, results showed that the degree of polymerization of the xylan improved 17.78%; and the films showed a significant increase in Young's modulus by 25.29%, tensile strength increased from 0.601 MPa to 0.753 MPa and 1.020 MPa to 1.218 MPa, respectively. The grafting between xylan and laccase-catalyzed oxidation of 4-coumaric acid played an important role in reinforcing the films. The superior properties of the new films could have great potential applications.
• Select
  The effect of Cr- and Mo-doped on band structure of single-layer WSe2: an ab initio study

  ;;

  . 2015, 46(10): 26-0.

  Abstract ( ) Knowledge map Save

  We study the band structure of Cr- and Mo-doped single-layer WSe2 by using an ab initio method of plane wave potential technique based on the density function theory. Our calculated results show the energy band structures of single-layer WSe2 are significantly affected by Cr doping, but not by Mo doping. With the increase of doping concentration, the effects of Cr doping manifest as the transition of energy band structure from direct to indirect, and the decrease of band gap. Our analysis reveals that strain is the direct reason for the change of band structure in the Cr-doped WSe2.
• Select
  Preparation and Performance Study of cross-linked Zein/PVA-SbQ composite nanofibers Spun by Electrospinning

  . 2015, 46(10): 27-0.

  Abstract ( ) Knowledge map Save

  Zein/PVA-SbQ composite nanofibers blend with different mass ratios were fabricated by electrospinning. Then the nanofibers were irradiated under UV light to get the cross-linked ones. The morphologies and diameter distributions of Zein/PVA-SbQ composite nanofibers were observed by SEM. The spectra of FT-IR indicated that two compositions of composite nanofibers maintained their own original functional groups. The thermal properties of composite nanofibers were studied by DSC, the results from characterizations revealed that the composite nanofibers still maintained superior thermal stability with the addition of PVA-SbQ. The results of CA elucidated the hydrophobicity decreased for composite nanofibers with increasing PVA-SbQ composition. The strength test showed that the addition of PVA-SbQ increased the tensile strength of composite nanofibers.
工艺 技术
• Select
  Effect of Moist-Heat Treatment on the Properties of Bombyx mori Silk Fibers

  . 2015, 46(10): 28-0.

  Abstract ( ) Knowledge map Save

  Bombyx mori (B.mor) silk was composed of natural fibroin, and could be attacked by light, heat, water, and microorganisms, etc. The changes of the structure and properties of B.mori silk fiber induced by moist-heat treatment were determined. It was observed that as the relative humidity increase from 0% to 70% at 150℃ decrease its tensile strength. Introducing water to the ageing environment promoted hydrolytic degradation. The concentration for serine and tyrosine decreased significantly as the relative humidity increasing, which resulted in increasing in yellowness index. The crystalline structure of silk fiber did not show any significant change except processing a slightly crystallinity arising.
• Select
  Preparation and Application of Sodium Alginate/Cellulose Hydrogel Beads

  . 2015, 46(10): 29-0.

  Abstract ( ) Knowledge map Save

  Different mass fraction of sodium alginate/cellulose hydrogel beads were prepared by the falling ball method based on reversal pH and characterized by scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR).The results showed that sodium alginate/cellulose hydrogel beads including less than or equal to 50% sodium alginate(mass fraction) can keep a stable spherical structure with 3D network porous structure and have a good adsorption performance of cationic dyes (methylene blue, auramine O and safranine T). The adsorption capacity of methylene blue on the hydrogel beads containing 50% sodium alginate(mass fraction) was 163.36 mg/g.The adsorption was well described by pseudo-second-order kinetics and they still keep the initial 81% adsorption capacity after five times adsorption-desorption experiment.Therefore,the compound hydrogel beads could be employed as a low-cost alternative to other adsorbents in the removal of dyes from aqueous solution.
• Select
  Preparation of Super-phobic SiO2 Aerogel Powder by Using the Microemulsion Method

  Ning Zhang

  . 2015, 46(10): 30-0.

  Abstract ( ) Knowledge map Save

  SiO2 nanopowder aerogel was prepared using silicon source of water glass and dispersion of medium kerosene by microemulsion method in ambient pressure dying process to prepare. The aerogel has good properties of high specific surface area, uniform particles, and super-hydrophobic. Surfactant weight, dying time, and the density of the aerogel power were investigated. Also this study researched the particle size, specific surface area, morphology and hydrophobicity. Results show that the aerogel powder prepared by microemulsion method has the superiorities of uniform particle size, high efficiency and super-hydrophobic.