30 January 2012, Volume 43 Issue 02
    

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    研究与开发
  • Raman and XPS analyses of carbon nitride nanostructure materials
    Xuan Chen
    . 2012, 43(02): 137-139.
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    Carbon nitride nanostructure materials with different structures were prepared by plasma-enhanced hot filament chemical vapor deposition under different conditions. Their structures were analyzed by scanning electron microscopy (SEM), micro-Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), respectively. The SEM images show that carbon nitride nanotips, cones and fibers can be formed under different growth conditions. Raman spectra exhibit the D and G peaks at about 1350 and1607cm-1, which indicates that the prepared materials are mainly composed of sp2 carbon. According to the intensity ratio of D to G peak, the sp2 carbon clusters are estimated to be about 4 nm. Each XPS spectrum shows a peak related to nitrogen at 398.4 eV, which illustrates that nitrogen is incorporated into the prepared materials. After the N 1s XPS spectra were fitted, it was found that each fitting peak was composed of two peaks at about 398.3 and 400.0 eV. The two peaks are related to sp3 and sp2 C-N bonds, respectively, which indicates that the carbon atoms in the materials are partically replaced by nitrogen atoms.
  • The microstructure and electrochemical performance of LiFePO4 prepared by different Li sources
    Hong YANG;Yun-Gun Chen
    . 2012, 43(02): 144-147.
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    LiFePO4/C composites were synthesized by two step solid reaction process using Li2CO3、LiOH?H2O、LiNO3、LiF as Li sources. It was found that LiFePO4/C composites prepared with different Li-containing compounds exhibited obvious differences in the microstructure and electrochemical performance. LiFePO4/C synthesized by LiOH?H2O showed the best electrochemical property, with a high discharge capacity of 161 mAh/g at 0.1C, 117 mAh/g at 1C and excellent cycle stability. The different electrochemical performances of LiFePO4/C composites by different Li sources may be contributed to their difference in the particle size, particle size distribution, degree of agglomeration and purity.
  • Preparation and Properties of Bamboo Charcoal Polypropylene Fibers
    Wang-Xi Zhang;Zu-Pei Yuan;Yan-Zhi Wang
    . 2012, 43(02): 148-151.
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    Polypropylene (PP) had been compounded with bamboo charcoal (BC) modified by nano-TiO2 for preparing 3 wt% BC/PP masterbatch using a twin-screw extruder, and the BC/PP fibers were prepared using high-speed melt-spinning device. The particle size and distribution of BC powders were characterized by Mastersizer 2000 laser particle size analyzer, scanning and transmission electron microscopy (SEM and TEM). The physical properties of masterbatch and fibers were examined using SEM, FTIR and TG/DSC. These techniques indicated that the BC particle size was found to be less than 5.8 μm and the particles were dispersed uniformly in PP matrix. The diameter of the BC/PP fibers was 25～80μm, the surface was not smooth as the BC particles were distributed on the surface of the fibers. IR spectra showed that BC/PP fibers and pure PP fibers had the similar spectral fingerprint area, but BC/PP fibers appeared CO2 absorption peak. TG result showed that the addition of BC powders accelerated the degradation of PP. The antibacterial effects of the BC/PP fibers were assessed from inhibition zone and shake flask test, and an excellent antibacterial performance was discovered against E.coli.
  • Preparation of Activated Carbon From coal tar residue by Chemical Activation with phosphoric acid
    Lei Gao;Fa-Qin Dong;Qun-Wei Dai
    . 2012, 43(02): 152-155.
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    Studying on the activated carbon was prepared from coal tar residue by phosphoric acid carbonization and activation with one stage at the condition of 400℃~1000℃,which sampled in Shaanxi province. Taking the temperature and time of carbonization and activation, the ratio of material to phosphoric acid as influencing factor, researching the effect of them on absorption and pore structure. The results revealed that the yield of activated carbon was affected by the temperature and time of carbonization and activation mainly, the active agent adsorption property and pore structure was affected by the temperature of carbonization and activation and the ratio of material to phosphoric acid, high temperature and long time will lead to more carbon loss. Experimental results show that the optimized process for preparation of activation is 850℃、3h、1:3. Through measuring the properties of activated carbon including the pore size distribution as well as the surface functional group idcated that :soaking coal tar residue with phosphoric acid is benefit to produce more large and medium pore structure on activated carbon, The pore size distribution of coal tar residue activation carbon is about 20nm - 100nm.
  • Self-crosslinkable Styrene-acrylic Copolymer as Surface Sizing Agent of Recycled-Fiber Sheets
    Yan-Na Zhao;Yi-Ding Shen
    . 2012, 43(02): 156-158.
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    Self-crosslinkable styrene-acrylic copolymers were successfully prepared by soap-free emulsion polymerization, using vinyltriethoxysilane as acrosslinking agent and polyvinyl alcohol(PVA) as polymeric colloid stabilizer. The synthetic processwas optimized. According to the application results, the optimum reaction conditionswere described as below: when w(AM)=9%, w(VTES) =5%. Moreover, the applied properties of the sized paper were measured as follows when the dosage of the surface sizing agent was 0.2% self-crosslinkable styrene-acrylic copolymers and 5.0% oxidation starch : the sizing value can reach 66s, picking velocity can reach 3.8s and folding endurance 15 was times. The Self-crosslinkable Styrene-acrylic Copolymer was characterized by FT-IR and TEM, the results indicate the formation of Si-O-Si of membranes and the incorporation of VTES does not increase the size of emulsion.
  • Preparation of Graft Copolymer of Phenols and Starch by HRP-Catalyzed System and Characterization of Structure and Properties
    Sheng-Hua Lv;Rui-Gong;Xiao-Liang Yan
    . 2012, 43(02): 159-162.
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    A graft copolymer was synthesized by means of radical copolymerization of phloroglucinol (PG)、Hydroxyl benzene sulfonic acid sodium(HBS) and degraded starch which was degraded by ?-amylase and the graft copolymerization was catalyzed by hrseradish peroxidase (HRP)/H2O2. It was investigated the effects of degradation degree of starch, monomer ratio of phenols, the dosage of HRP, polymerization temperature and pH value on structure and properties of modified starch. The optimum reaction conditions were obtained as follows: mass ratio of PG to HBS 12:20, 15g starch which was degraded by α-amylase, polymerization 30 °C pH 7.0 and 5 mg of HRP solution. The surface tension of modified starch solution was 26.6mN/m and the shrinkage temperature (Ts) of tanned leather reached 78°C. Meanwhile the chemical structure of the graft copolymer was characterized by FTIR, 1H-NMR, UV-Vis and GPC.
  • Preparation of Bunches of Aligned Boehmite Nanowires
    Zhen-Feng Zhu;Zheng-Yang Zhang;Hui Liu
    . 2012, 43(02): 163-165.
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    A simple method based on a hydrothermal process using （C8H11NaO7）n as template is proposed for the synthesis of aligned bunches of boehmite (γ-AlOOH) nanowires. Most bunches of aligned boehmite nanowires are with widths of 800 to ~900 nm and lengths of about 2μm. XRD patterns, FTIR spectra, and SEM and TEM images were used to characterize the products. The absorption of RhB can be indexed the products have a good property of abaorption. The importance of adding（C8H11NaO7）n for the formation of bundle morphologies has been discussed.
  • Effect of Electromagnetic Field on Solidification Structures and Segregation of Lead Brass Billets by Horizontal Continuous Casting
    Zhi-Qiang Cao;Ji-Long Kang;Yan-Ju Li
    . 2012, 43(02): 166-169.
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    Abstract: The macrostructure、microstructure and distribution of Pb element of horizontal continuously cast billets of Lead brass were investigated, which was solidified under the actions of no electromagnetic field and with electromagnetic field, separately, and theoretically interpreted .Experimental results show that the structure of lead brass is refined effectively and distribution of Pb element is affected with the application of electromagnetic field during horizontal continuous casting, what，s more, the phenomenon that the uneven distribution of structure over the cross-section of the traditional horizontal continuous casting is suppressed, that is, the solidification structure of the top mainly being small columnar crystal, the bottom being coarse columnar grains changes to all of fine equiaxial ones. When the electromagnetic field is added, the solidification lag of ingot，s upper is eliminated; the macro-segregation of Pb element is suppressed, and the solidification structure of 30Hz、100A is better than that of 30Hz、80A.
  • Study on Rheological Behaviors of Collagen
    Shi-Wei Xiao;Hai Lin;Wei-Hua Dan
    . 2012, 43(02): 170-173.
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    In this study, the rheological behaviors of collagen solutions prepared with collagen extracted from pigskin were studied at different concentration. By means of fitting the Ostwald de Wale model and based on the good fitting degree, the dependence of viscosity on collagen concentration, temperature and shear rates was analyzed. Results revealed that this collagen solution has pseudo-plastic behavior. And the concentration of solutions increased, the value of non-Newton index get smaller, the pseudo-plastic behavior appeared more obviously. Viscosity of different concentration declined increasingly with increasing shear rate and temperature. The higher concentration it is, the higher viscosity it has, the larger the value of Eη is and the more sensitive it is to temperature.
  • Synthesis and mineralization behavior study of bionic functional chitosan
    Shan Ding;Min-Jian Tang;Chang-Ren Zhou
    . 2012, 43(02): 174-177.
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    Cholesterol-modified chitosan conjugate with succinyl linkages (CHCS) was synthesized and characterized by fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR). The mineralization behaviors of CHCS were performed with a rapid and facile approach. Results revealed that CHCS have the ability of guided the apatite which similar to organisms’ bone formation. With the ratio of cholesterol grafted increased the effect of CHCS guidance of bone-like apatite formation strengthened. And the deposited apatite present an order accumulated was similar to organisms’ bone.
  • Floating Zone Growth and Characterization of Single Crystal REB6(LaB6，CeB6)Cathode
    Ning Zhang;Jiu-Xing Zhang
    . 2012, 43(02): 178-180.
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    The high quality, high purity and large size LaB6，CeB6 single crystals have been successfully grown by optical floating zone method.Each parameter which impact in the process of crystal growth was studied in this article. We determine the optimum crystal growth (a)LaB6: speed of 30rpm, the growth rate of 8-10mm/h,twice zone melting (b)CeB6: speed of 30rpm,the growth rate of 15-20mm/h,once zone melting. And then analysis the characterizations of single crystals. We use the main method, and they are single crystal diffraction, Raman diffraction, rocking curve, cross-section scanning. These are show that floating zone growth is the best method in the produced single crystal REB6 (LaB6, CeB6) cathode.
  • Preparation and Characteristics of Deoxycholic acid-modified pullulan nanoparticles
    Yan-Ping Shi
    . 2012, 43(02): 181-184.
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    To synthesize Deoxycholic acid-modified pullulan derivation (DP) by coupling Deoxycholic acid to pullulan and prepare nanoparticles（DPNs） by nanoprecipitation. The effects of different parameters on the nanoparticles formation were investigated for further research of the DP as targeting anti-tumor drug carriers. FI-IR spectroscopy (Bio-Rad Merlin) and 1H-NMR (INOVA 500Hz) were used to confirm the synthesis of the DP. The physicochemical properties of the nanoparticles were characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential. DP with different degree of substitution were synthesized. The TEM demonstrated that the shape of nanoparticles was spherical with smooth surface. The mean diameter was in the range of 100~300 nm and zeta potential was -20mv. Deoxycholic acid-modified pullulan was formed nanoparticles by nanoprecipitation. Their physicochemical properties were affected by parameter of preparation.
  • Synthesis and Thermo-Responsive Property of End-Functionalized Poly(N-Isopropylacrylamide) with Two Saccharide Groups
    Zheng-Guo Gao;Yuan Cui;Xiang-Dong Tao
    . 2012, 43(02): 190-195.
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    Two kinds of derived carbohydrates (AcCDBr and AcGlABr) were synthesized as the initiators for atom transfer radical polymerization (ATRP) of N-isopropylacrylamide. The polymerizations of end-functionalized poly(N-isopropylacrylamide) with different saccharide groups (CD-PAM and GlA-PAM for short) were carried out using CuBr/tris(2-dimethylaminoethyl)amine(Me6TREN) as the catalyst system with the feed ratio of [monomer]0:[initiator]0:[CuBr]0:[Me6TREN]0 = 50:1:1:1 in DMF/water at 60 °C. The structures of the initiators and the polymers were characterized by means of FT-IR and NMR. Low polydispersity indices (PDI = 1.12~1.20) were obtained by gel permeation chromatography (GPC). Ultraviolet-visible spectroscopy (UV-vis) and differential scanning calorimetry (DSC) were employed to measure the lower critical solution temperature (LCST) of the end-functionalized PNIPAMs. The results showed the LCSTs of end-functionalized PNIPAM were increased due to the hydrophilicity of the saccharide groups, and the LCST of GlA-PAM was about 3.7 °C higher than that of CD-PAM. Furthermore, the end-functionalized PNIPAM showed an inverse molecular weight dependence of their cloud points.
  • Compression-sensitivity of Conductive Silicone Rubber Composites
    Bo Liao;Guo-Qing Zhou;Teng-Fei Wan
    . 2012, 43(02): 196-199.
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    The compression-sensitivity and repeatability of short carbon fiber/carbon black-silicone rubber conductive composites are studied by single and circular compression test. The results show that both conductive composites have the better compression-sensitivity. The composites carbon fiber filled have high sensitivity (gage factor about 250) and have linear relationship between the value of relative resistance and strain while the composites filled with carbon black have better reproducibility, but poor sensitivity. The sensitivity of the two composites are analyzed through the conductive mechanism.
  • Preparation and property characterizations of HAp-5.0wt.%SiO2 bioceramic composites
    Xue Zhang;Xiao-Wu Li
    . 2012, 43(02): 200-204.
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    Abstract: HAp-5wt.%SiO2 bioceramic composites were prepared successfully by sintering the powders of hydroxyapatite (HAp) mixed directly with additive of 5.0wt.%SiO2 at 1200℃. XRD and FT-IR analyses of the sintered samples demonstrate that the SiO2 additive promotes the thermal decomposition of HAp. The major phase compositions of the HAp/SiO2 composite consist of α-TCP, HAp, Ca2P2O7, bioglass (BG), and etc. The in vitro bioactivity assessments show that the petal-like apatite sediments appear on the surface of the sample after soaking for 24 hours in stimulated body fluid (SBF), and the plate sediments form as the soaking time is increased to 72 hours. After further immersing up to 120 hours, the sample surface is fully covered by a thicker bone-like apatite layer. XRD analyses indicate that the apatite layer is mainly composed of hydroxycarbonate apatite (HCA), which is the major inorganic component of the human bone. As compared with pure HAp, the synthesized HAp-5wt.%SiO2 bioceramic composite has a superior in vitro bioactivity, and it can be expected to act as a potential material for bone repair.
  • Study on the Performances of a New Anti-radon Paintcoat in Underground Engineering
    Rui-Xue QU
    . 2012, 43(02): 205-208.
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    This research focus on the performances of a new anti-radon paintcoat which is suitable for the special high humidity and inclosed environment. Test results of the radon mitigation efficiency using the local static method and the RAD7 radon detector test show that the radon mitigation efficiency is rising along with the coating thickness of the paintcoat, the radon mitigation efficiency is superior 92% when the coating thickness is 0.8mm, in the meanwhile, the radon mitigation efficiency reach to 98.91% and 99.02% when the coating thickness is 2.0mm and 2.4mm respectively. The hard dry time of this new anti-radon paintcoat is 12.1h when the temperature is 23.7℃, the RH is 95% and the thickness is 2.0 mm. Researches of the aging resistance of the new anti-radon paintcoat show better performance in resistancing to high concentration of radon radiation, hot and humidity as well as resistancing to mould fungus. So, the new anti-radon paintcoat can well meet the demanding application-required of underground engineering.
  • Preparation and Performance of Polyacrylate/nano-TiO2 composite
    Jun-Li Liu;Jian-Zhong Ma;Yan Bao;Zhen-Feng ZHU
    . 2012, 43(02): 209-212.
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    Polyacrylate/nano–TiO2 composite was prepared through emulsion-free in-situ polymerization stabilized with polymerizable surfactant allyloxy nonylphenol propyl polyoxyethylene ether sulfate(DNS-86). The structure of the composite were characterized by fourier transform infrared spectroscopy (FTIR), dynamic laser light scattering (DLS), transmission electron microscopy (TEM) analysis. Effect of nano-TiO2 on the properties of composite were studied by mechanical properties and water resistance test. FTIR analysis showed a small amount of nano-TiO2 was grafted to the polymer. DLS analysis indicated both the average diameter and the polydispersion index of polyacrylate/nano–TiO2 composite latex decreased in compared with pure polyacrylate. TEM analysis demonstrated TiO2 was distributed in polymers. The result of properties analysis shows polyacrylate/nano–TiO2 composite has better mechanical properties when the dosage of TiO2 is 0.5%. Nano-TiO2 can improve water resistance of polyacrylate.
  • Study on the preparation、microstructural analysis and mechanical property of polypropylene mesh containing nano-silver
    Bi-Si Wang;
    . 2012, 43(02): 213-216.
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    AbSTRCT OBJECTIVE: Explored an effective method to preparation polypropylene mesh containing nano-silver，and studied on its mechanical property and microstructural analysis。 METHODS: Polypropylene antibacterial chips containingnano-silver were prepared by blending and granulation.And prepared to the corresponding polypropylene mesh containing nano-silver（divided into 6 group）.Then tested their mechanical property and microstructural analysis:In order to investigate the influence of the different additives of nano-silver on the mechanics properties of polypropylene mesh. And observed the agglomeration of nano-silver in different samples. RESULTS AND CONCLUSION: With the corresponding process,the mechanical property of polypropylene mesh containing nano-silver could be preparated：In each group, nano-sliver could improve the mechanical properties of fiber,without significantly influenced of their weight, fiber forming and fibrillation; Overall,the agglomeration increases with the nano-sliver increased，but the phenomenon was not to much. The adding dosage of nano-sliver should under further study，not only to get the balance between the antibacterial activity ,mechanical properties and weight of the mesh,but also provides a new way to get medical antibacterial polypropylene mesh.
  • Research on the Crack Induced by Sulphate doping on KDP Crystal
    Yun Sun;Sheng-Lai Wang;Qing-Tian Gu
    . 2012, 43(02): 217-221.
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    In this paper, KDP crystals were grown by the traditional temperature lowing method from the aqueous solution doped with different concentrations of SO42- ion. The macro defects and crack models have been analysis in detail. The main reason that causing KDP crystal crack were analysis from the view point of crystal growth. The experiment indicate that, the main crack model of KDP crystal is vertical to the growth layer of {101} face with the rise of the dopant concentration. The crystal sectors which have many cracks also have many mother liquor inclusions. With the doping concentration increase, the quality of KDP crystal decreased heavily.
  • An Identification and Characterization for the dynamic Recrystallization Critical Conditions of Ti-6Al-2Zr-1Mo-1V Alloy
    Guo-Zheng Quan;Lei Zhao;Yan-Wei Zhang
    . 2012, 43(02): 222-226.
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    The true stress-strain curves of Ti-6Al-2Zr-1Mo-1V alloy were achieved by a series of isothermal compression tests under the deformation temperatures of 1073～1323K and the strain rates of 0.01～10s-1, which would be taken as the basic data for identifying and further characterizing the critical conditions of dynamic recrystallization(DRX). Through comparison of flow stress curves under different deformation conditions, it’s found that in low temperature, high strain rate conditions softening effect is mainly due to dynamic recovery, while in high temperature, low strain rate conditions due to dynamic recrystallization. Based on the true stress-strain data, curves under different deformation conditions were obtained through introducing hard working rate. Combined with the infection criterion of curves, two potential parameters were identified as following: the critical strain and the critical stress for DRX, which contribute to characterizing the initiation of DRX evolution. The Arrhenius equation was introduced for calculating several important material constants such as , , , ,and further for response surface of the activation energy of DRX to strain rate and deformation temperature. A critical stain model representing the DRX critical conditions was further adopted and the mathematical relation between critical strain and thermodynamic parameters during hot deformation was explicated. Final simulation results show that the critical model is of high precision.
  • Preparation of porous silica fibers impregnated with superacid and its application in esterification
    Jin-Xi Lin;Jing He;Ma-Tai Ding
    . 2012, 43(02): 227-230.
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    E-glass fibers are acid-leached to prepare porous silica fibers. The fibers are impregnated with sol and heat-treated to produce SO42-/ZrO2 solid superacid catalyst. This catalyst is used in the synthesis of n-butyl acetate. It has been found that the solid catalyst has high surface area and high activity. It is more effective than liquid superacid or nano-powder supported solid superacid. Consequently, the catalyst consumption can be reduced and the yield of esterification is improved. Moreover, this catalyst can be recovered easily by filtration. After 5 times of recovery, the catalyst can still give a good esterification yield of over 70%.
  • Aluminum-induced crystallization and Grain preferred orientation characteristics of polysilicon thin flims
    Wei Yu;Ya-Ping Guo
    . 2012, 43(02): 231-234.
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    Polycrystalline silicon (poly-Si) films were prepared from amorphous silicon (a-Si) films by aluminum-induced crystallization ( AIC) method，and the nucleation and growth mechanism of the poly-Si films was studied. Amorphous silicon (a-Si) films were deposited on glass substrate by plasma enhanced chemical vapor deposition (PECVD), and then annealed in N2 atmosphere at different temperatures after aluminum(Al) layer was sputtered on a-Si film’s surface. The results show that the film sequence of Si layer and Al layer was exchanged after annealing, and the average grain size of the poly-Si was about 150 nm. X-ray diffraction results reveal that the film’s crystal orientation was particularly dependent on the annealing temperature. At the low temperature, the AIC speed was at a lower level, and the crystal orientation was related on atom arrangement trend of the a-Si film’s initial cluster. While at high temperature, the AIC played a key role on preferential nucleation of the poly-Si (111) and the subsequent solid phase growth process.
  • Effect of Magnetic Field on the Absorption of Schiff Base for Pb(II)
    Li-Hong Duan
    . 2012, 43(02): 235-239.
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  • Preparation of Expanded graphite-based carbon/carbon composite electrode and its degradation of phenol
    Tai-Bin Wang;Zhi-Gang Chen;Feng Chen
    . 2012, 43(02): 240-243.
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    Abstract: Expanded graphite-based carbon/carbon composite electrode (EGC electrode) has been made of compressed expanded graphite impregnated by sucrose-phosphoric acid solution. The microstructure of the composite electrode has been investigated by nitrogen adsorption method and SEM. The influence of initial sucrose concentration on the surface structure and porous characteristics has been investigated, as well as the impact of electrolytic conditions on phenol degradation. The results indicate that the EGC electrode is comprised of a graphite backbone coated by a thin layer of activated carbon. The pore width distribution is among 0.5-2.5 nm. The EGC electrode could obtain the highest surface areas as the sucrose concentration reaches 50%, and it performs highly effectively in electrochemical oxidation of phenol. The data shows that the removal efficiency of phenol increases with lowering the initial phenol concentration and increasing the current density and electrolyte concentration.
  • Effects of Insulation Coating on Magnetic Properties of Fe78Si9B13 Amorphous Magnetic Powder Core
    Ying-Lei Ren;Zi-Jian Ling;Jun-Hua You
    . 2012, 43(02): 244-246.
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    In this experiment, the Fe78Si9B13 amorphous powder crashed by airflow is used to prepare magnetic powder core. Effects of passivant addtion, binding admixture content and insulating compound content on magnetic properties of magnetic powder core are investigated by scanning electronic microscope and B-H analysis meter in the insulation coating process . The results indicate that: The passivant addtion can improve frequency character, reduce the magnetic loss and increase the quality factor. Eddy current loss can be reduced by increasing the insulating compound content, but excessive insulating compound can reduce the magnetic permeability. The best binding admixture content is 3.5%.
  • Magnetic phase transitions and Magnetocaloric properties of Gd2Co2Al alloy
    Qiang Zheng
    . 2012, 43(02): 247-249.
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    Gd2Co2Al alloy synthesized by arc melter was W2Co2B-type single-phase structure in the as-cast state. It can be seen from the temperature dependence magnetization that three magnetic phase transitions occurred at 40K, 80K, and 215K, respectively, when the applied field was under 1 kOe. However, only one transition occurring at 80 K can be observed when the applied was above 10 kOe. It was speculated that the transitions at 215K and 80K corresponded to the ordering temperatures of Co, and Gd sub-lattice, respectively, and the transition at 40 K was a spin-reorietation. The maximal magnetic entropy change(-ΔSMmax) under 0-50kOe is about 10.7J/kgK occurring at 80K and the relative cooling powder (RCP) is about 5.4×102J/kg, which makes Gd2Co2Al alloy a promising candidate magnetic refrigerant near liquid-nitrogen temperatures.
  • Preparation and Electrical Properties of BiFeO3 Films on FTO/Glass Substrate by Chemical Solution Deposition
    Meng Cheng;Guo-Qiang Tan
    . 2012, 43(02): 250-252.
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    Abstract: BiFeO3 thin films were prepared on hydrophilic FTO/glass substrate by chemical solution deposition. XRD, FE-SEM, XPS, Agilent E4980A precision LCR meter and TF-Analyzer2000 were used for the characterization of BiFeO3 thin films. The results indicated that the thin films were the well-crystallized BiFeO3 thin film with multi-crystals and pure phases. BiFeO3 crystalline grain with 100-300nm diameter were piled up and formed densely. The surface appeared even and level. The thickness of the thin film was 450nm. The oxidation state of Fe was Fe3+. There was no Fe2+ present. At 10 KHz, the dielectric constant and dielectric loss were respectively 134 and 0.005. The remanent polarizability of the thin film was 0.58μC/cm2. Under the testing electric field of 0～250KV/cm, the leakage current step remained 10-6A/cm2
  • Methodology for Prediction of Triplet Energy Level of the Ligands of Tb3+ by Quantum Chemistry Calculation
    Qi-Qin Zhang;Qi-Liang Pan;Hu-Sheng Jia
    . 2012, 43(02): 253-256.
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    Three Tb (III) complexes were synthesized using 2-Aminobenzoic acid (ＨL) as primary ligand and 1, 10-Phenanthroline (Phen) and triphenylphosphine oxide (TPPO) as neutral ligand. The structure of the complexes was characterized with IR spectrum. The result shows that both amino and carboxyl were coordinated with Tb (III) ion, and Phen and TPPO were coordinated with Tb (III) ion. The luminescent properties were studied by UV-vis absorption spectrometry and fluorescence spectrometry. Luminescent intensity has the order of Tb(L)3(TPPO)2＞Tb(L)3(H2O)2＞Tb(L)3(Phen). The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), and the singlet and triplet energy levels of ligands were calculated by quantum chemistry calculation. Energy transfer process was researched into the Tb (III) complexes with different neutral ligands.
  • First-principles Study Of Na, N Acceptor Pair Co-doped P-type ZnO
    Xiao-Yu Jie;Hui-Qing Sun;Du-Yang Wang
    . 2012, 43(02): 257-260.
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    Abstract The geometry optimization of pure ZnO, Na, N single doped and Na-N co-doped wurtzite ZnO has been investigated by using first principle ultrasoft pseudo-potential approach of the plane wave based upon the density functional theory. Na, N co-doped ZnO has two cases which are Na, N connection and Na, N separation. Basing on the geometry optimization, the band structure, total density of states, partial density of states of these several kinds of wurtzite ZnO were studied. The results show that the effect of Na, N co-doped p-type ZnO is better than single-doped cases. Comparing to Na, N connection co-doped case, Na, N separation co-doped case could get a better p-type effect.
  • Effects of Spinning Parameters on the membrane performance of PVC/PVB Hollow Fiber Membrane
    Qiang Li
    . 2012, 43(02): 261-263.
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    Polyvinyl chloride (PVC)-Polyvinyl butyral (PVB) hollow fiber membrane was prepared by phase-inversion technique. The spinning parameters, such as different compositions of coagulation bath, speeds of bore fluid, speeds of winding and air gaps, were examined to investigate their effects on the performance of the membrane. The results demonstrated that different surface structures of hollow fiber membrane could be obtained by adjusting the solvent content in the coagulation bath. The inner diameter and wall thicknesse of membrane changed as the speed of bore fluid and winding changed. The water flux and the BSA rejection rate were controlled by adjusting the air gap. Hence, different properties of PVC/PVB hollow fiber membranes could be prepared by controlling the spinning parameters.
  • Electrochemical properties of AZ alloys as anode material of magnesium dry batteries
    Yi Cheng;Fu-Sheng Pan
    . 2012, 43(02): 264-267.
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    The electrochemical properries of AZ21 alloy and AZ31 alloy as anode materials for magnesium - manganese dry batteries were studied by weight lose、linear sweep voltammetry and discharge measurement of coin-type cells，and the affects of Li2CrO4 as inhibiter also were studied. The results show that：the corrosion rate and the open-circuit potentials of AZ21 alloy in Mg(ClO4)2 solution are higher than AZ31 alloy. The battery’s capacity and positibe utilization when AZ21 alloy as anode material are lower than AZ31 alloy. The corrosion rates of AZ21 and AZ31alloys were reduced greatly with a little Li2CrO4, and the inhibiton efficiency was increased with the addition of Li2CrO4，but it was reduced when the concentration over 0.3 wt.%. The Li2CrO4 also can improve the working voltage、battery capacity and positive utilization.
  • Study on polyacrylate/nano-TiO_2 composite for leather finishing agent
    Yan Bao;Bing Wang;Jian-Zhong Ma
    . 2012, 43(02): 268-272.
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    Polyacrylate/nano-TiO_2 composite was prepared via in situ polymerization, in which butyl titanate was used as precursor of TiO2, AM, VAc, BA, MA were chosen as monomers and A-151 was chosen as silane coupling agent. The effects of initiator and butyl titanate contents, reaction time on properties of polyacrylate/nano-TiO_2 composite emulsion and films were investigated. The structure of composite was characterized by FTIR and TEM. The results show that: with the dosage of initiator and butyl titanate increasing, the tensile strength of films decreases first and then increases, but the elongation at break increases first and then decreases. The water resistance of films increases first and then declines. With the prolonging of reaction time, the tensile strength and elongation at break of films show an opposite trend, compared with the dosage of initiator and butyl titanate. The water resistance of films presents downtrend basically. The FTIR and TEM show that Nano-TiO_2 exists in polyacrylate, and mainly exists in surface of the polyacrylate latex particles.
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