Advanced Materials Research Vols. 287-290

Abstract: The electrochemical performance of capacitor was studied with LiCoO₂/AC as composite cathode and activated carbon (AC) as anode, in 1.0 mol/L LiPF₆/EC+DMC electrolyte. Cyclic Voltammetary, Constant-Current Charge and Discharge, Electrochemical Impedance Spectrum (EIS) and Leakage Current Test were tested to study the characteristics of supercapacitors. The results illustrate that recharging voltage of hybrid supercapacitor can reach to 3.0 V and show good capacitance characteristics. The supercapacitor can rapidly charge and discharge and show good cycling performance. There is a great effect to the performance of the capacitors by adopting different proportional composite electrode. When the ratio of composite electrode is 6:4, we get maximum symmetrical Cyclic Voltammetary and short charge-discharge time only 26.4min; When the ratio is 7:3, the minimum AC impedance of 26.2W can be attained and least leakage current is only 19.92mA/g; When the ratio is 5:5, the best first specific capacity can reach to 70.17F/g but a lower capacity retention rate is 74.86%.

Abstract: The interaction between a screw dipole inside the matrix and an elastic elliptical inhomogeneity containing a confocal crack under longitudinal shear is investigated. By using the complex method of elasticity, singularity analysis of stress function and Riemann boundary problem, the complex functions of matrix and inhomogeneity are obtained in the series form. And the singularity stress field of matrix, the image force and image torque acting on the center of screw dipole and the stress intensity factor of crack tip are deduced. Then the influence of the dip angle of screw dipole, the size of inhomogeneity and the misfit of materials on image force, torque of couple and the stress intensity are analyzed. The results show that the image force varies periodically as and there is two critical value of to make image force getting its maximum and minimum; the decreasing of relative shear modulus and the increasing of inhomogeneity may lead to the increasing of image force; the variation of will change the direction of screw dipole on stress intensity factor.

Abstract: Polystyrene(PS)/Low density Polyethylene(LDPE) blends were prepared in a twin-roll mill. Effects of the addition of nano-CaCO₃, LDPE-g-MA, and the mixing procedure on the morphology, crystallization behavior, rheological and mechanical properties of the blends were investigated by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Advanced Rheometric Expansion System (ARES) and mechanical testing. The results show that the addition of nano-CaCO₃ reduces the droplet size and the crystallinity of LDPE dispersed phase, hence increases both the tensile and impact strength of the blends. The two-step mixing procedure in which LDPE and nano-CaCO₃ were premixed prior to mixing with PS, facilitates forming encapsuled morphology, leading to a lower viscosity and a higher tensile strength of the blends.

Abstract: The objective of this study is to decompose gaseous acetone ((CH₃)₂CO) by a self-prepared nano-sized composite TiO₂/In₂O₃/SnO₂ film photocatalyst that was prepared by a multi-target vacuum sputter operating at a vacuum pressure of 3 mtorr. The operating parameters investigated for the sputtering process included oxygen to argon ratio (O₂/Ar), sputtering temperature, substrate materials, substrate layers, and sputtering duration. The nano-sized composite TiO₂/In₂O₃/SnO₂ film photocatalyst was mainly composed of anatase with a few rutile. The surface roughness of the TiO₂/In₂O₃/SnO₂ film photocatalyst in terms of RMS ranged from 2.292 to 7.533 nm, while the thickness of the single- and double-layer film photocatalysts were 473.5 and 506.0 nm, respectively. Gaseous acetone was initially injected into and further degraded in a self-designed batch photocatalytic reactor containing the nano-sized composite TiO₂/In₂O₃/SnO₂ film photocatalyst. Experimental results indicated that the highest acetone degradation efficiency of 99.9% was obtained at 50°C and 1 atm with the incident of near-UV illuminated by a fluorescent black light lamp. Under the incidence of blue light (430-500 nm), the reaction rates of acetone decomposition were 2.353x10^-5 and 3.478x10^-5 μmole/cm²-sec for using single- and double-layer TiO₂/In₂O₃/SnO₂ film photocatalysts, respectively.

Abstract: The preparation of 5-hydroxymethylfurfural (5-HMF) through the dehydration of fructose with room temperature ionic liquids (ILs) has received much attention as a way of producing liquid fuels from renewable resources, but the cost of the process is considerably increased with IL as a solvent rather than as a catalyst. In this work, we have shown that the alkaline Ionic Liquid, 1-Butyl-3-methylimidazolium Hydroxide ([BMIM]OH), can be used as a catalyst in the conversion of fructose to 5-HMF. The maximum yield of 5-HMF was 91.6% at 160 °C after 8 h using dimethylsulfoxide (DMSO) as solvent, and the ketose is more easily dehydrated than aldose in this catalyst system.

Abstract: TiO₂ nano powder doping with Sn⁴⁺ was directly synthesized by a low temperature hydrothermal method using tetrabutyl titanate (TBOT) as a Ti resource and NH₄Cl as a dispersant. The synthesized nano powder was characterized by XRD, BET, TEM and EDS analyses. XRD results show that increasing reaction temperature facilitates to form a stable phase, and the synthesized nano power size is uniform with particle size of 10-20 nm. Doping Sn⁴⁺ ion does not result in an obvious lattice distortion. The effect of doping Sn⁴⁺ ion on photocatalytic activity in visible light region for modified TiO₂ was investigated by degrading methylene blue solution.

Abstract: The experiments of alkali lignin degradation were catalyzed by phosphomolybdic acid H₃PMo₁₂O₄₀ and ultrasonic in homogeneous and heterogeneous reaction. The reaction time, solvents in the reaction, the concentration of phosphomolybdic acid were discussed by the analysis of active functional groups of degraded lignin. The results showed that contents of functional groups increased after degradation by phosphomolybdic acid in both homogeneous and heterogeneous reaction.

Abstract: Nano-catalyst was prepared in the lab. Non-thermal plasma was generated by dielectric barrier discharge (DBD). Through nano-catalyst coupled with non-thermal plasma, a series of experiments for toluene decomposition were carried out. Based on reactor input energy density and removal efficiency and energy efficiency and inhibition for O₃ formation, the load amount MnO_x catalyst on the surface of γ-Al₂O₃ pellets were compared in the experiment. The results show the catalysis performance of 10 wt% MnO_x/γ-Al₂O₃ coupled with non-thermal plasma resulted in higher removal efficiency of toluene and better energy efficiency. At the same time, 10 wt% MnO_x/γ-Al₂O₃ operated on a better inhibition for O₃ formation in the gas exhaust.

Abstract: After reviewing deficiencies of organic foundry binders such as furan, phenolic resin, the author in this paper introduces a new inorganic binder which is colorless and tasteless and does not burn when contacted with liquid metal and has no smoke and other harmful materials to emit into atmosphere. In the paper, the hardening characteristic and properties of inorganic binder nobake and heat hardened sand such as tensile strength, humidity resistance, gas forming and collapsibility are investigated. Foundry trials were carried out to prove that the new binder meets practical requirements.

Abstract: In this work, carbon nano-tube/TiO₂ (CNTs/TiO₂) nanocomposites were prepared using a conventional sol-gel method. To further obtain a uniform catalyst film, chitosan (CS) was used as a crosslinker for the CNTs/TiO₂ composite. The structure and property of CNTs/TiO₂/CS film were characterized using XRD, FT-IR, TEM, SEM, and UV-vis. The photocatalytic activities of CNTs/TiO₂/CS film were measured through the photocatalytic degradation of gaseous formaldehyde. Compared with the commercial TiO₂, higher degradation was achieved with the CNTs/TiO₂/CS film due to stronger absorbability and synergetic effect among CNTs, TiO₂, and CS.