Advanced Materials Research Vols. 415-417

Abstract: It has come to light that the poor electrochemical cycle stability of RE-Mg-Ni based AB₃ and A₂B₇-types electrode alloys limited their practical application as the negative electrode materials of Ni-MH battery. In order to improve the electrochemical cycle stability of the La-Mg-Ni system A₂B₇-type electrode alloys, La in the alloy is partially substituted by Pr and the melt-spinning technology was used for preparing La_0.75−xPr_xMg_0.25Ni_3.2Co_0.2Al_0.1 (x = 0-0.4) electrode alloys. The microstructures and electrochemical cycle stability of the as-cast and spun alloys were investigated. The results obtained by XRD, SEM and TEM show that the as-cast and spun alloys have a multiphase structure which consists of two main phases (La, Mg)₂Ni₇ and LaNi₅ as well as a residual phase LaNi₂. The substitution of Pr for La gives rise to a visible grain refinement of the as-cast alloys instead of changing the phase structure of the alloys. The electrochemical measurement indicates that the cycle stability of the alloy remarkably grows with increasing both Pr content and spinning rate.

Abstract: We reported enhanced characteristics of the organic solar cells (OSCs) using pyromellitic dianhydride (PMDA) material as cathode interfacial layer. This PMDA cathode interfacial layer was used in a bilayered structure consisting of lithium fluoride (LiF) and pyromellitic dianhydride (PMDA) at the interface of poly(3-hexylthiophene-2,5-diyl)(P3HT)+[6,6]-phenyl C61 butyric acid methyl ester (PCBM) and Al. Better performance enhancement compared to OSCs without a cathode interfacial layer or with a single LiF interfacial layer was achieved by using a bilayered interfacial structure. The OSC with a cathode interfacial structure with LiF and PMDA combination showed 2.08 % power conversion efficiency (PCE) value, while the OSC with a single LiF cathode interfacial layer showed 1.72 % PCE value and the OSC without any cathode interfacial layer showed 1.35 % PCE value, respectively. And Cole-Cole plots of OSCs showed that bilayered interfacial structure reduced impedance probably by improving the electron transport between Al and PCBM+P3HT.

Abstract: For the purpose of improving the reproducibility and the semiconductor properties of chalcopyrite CuInS₂ thin film, potassium hydrogen phthalate (C₈H₅KO₄), as a complex agent, was added into the sulphate bath system. The optimum process parameter for the preparation of CuInS₂ thin film was determined by orthogonal experiment method. The effect of C₈H₅KO₄ on the composition and Mott–Schottky behavior of the as-deposited film was studied with electron dispersion spectroscopy (EDS) and alternating current (AC) measurement. It was found that the as-deposited film was p-type semiconductor with the flatband of 0.665 V and the acceptor density of 3.06×10¹⁹ cm^-3; the addition of C₈H₅KO₄ can effectively enhance the composition stability of the film and decrease its flatband potential and acceptor density.

Abstract: Polycrystalline filled Skutterudite compounds Ba_xCo₄Sb₁₂ (0-x-0.5) are synthesized by high pressure and high temperature （HPHT） technique. The thermal conductivity for CoSb₃ is depressed significantly by Ba-filling combined HPHT technique. The value of 1.25 Wm^-1 K^-1 for Ba_0.372Co₄Sb₁₂ is obtained at 633K. The dimensionless thermoelectric figure of merit ZT, increases with temperature increasing and reaches a maximal value of 1.01 at 663 K.

Abstract: Blends of Corn gluten meal (CGM) and poly (lactic acid) (PLA) plasticized with glycerol, water and ethanol, were extruded into pellets using single-screw extruder, and the pellets were compression-molded into composites, and the tensile strength, water resistance, thermal stability and morphology of the composite were evaluated. The results showed that PLA reinforced the composite, improved the water resistance. The structure of composite was observed by scanning electron microscopy (SEM), it was showed that PLA formed a network structure, and the modified CGM inlay in network. The result of thermal gravimetric analysis (TGA) considered that the composite could keep thermal stability below 180 °C.

Abstract: The present study evaluated the properties of the polymeric blend films obtained from chitosan and corn starch using glutaraldehyde as crosslinking agent and glycerol as plasticizer by the casting/solvent evaporation method. Fourier transform infrared (FTIR) analyses confirmed that the groups interactions of starch and chitosan in starch-chitosan blend films were present especially when using glutaraldehyde as crosslinking agent. Differential scanning calorimetry (DSC) studies revealed an endothermic peak of starch film at 98 oC corresponding to water evaporation. DSC also indicated that the endothermic peak of blend films moved to higher temperature with adding chitosan and glutaraldehyde compared with native corn starch film. The tensile strength of the blend films increased with the increasing content of glutaraldehyde. The starch-chitosan blend films exhibited the highest tensile strength of 11 MPa when the content of starch was 9% (w/v in water), glutaraldehyde content was 1.0 mL, chitosan ratio is 0.35 (w_chitosan/w_starch), glycerol ratio was 0.35 (w_glycerol /w_starch).

Abstract: In this paper, ions i.e. Cu²⁺, Pb²⁺and Cd²⁺ were absorbed by the carboxyl bagasse hemicelluloses, and the influences of pH value, adsorption time and the initial concentration of metal ion have been studied. The results show that the optimal adsorption pH values for Cu²⁺, Pb²⁺and Cd²⁺ are 5.5, 5.5 and 7.5, respectively. The adsorption capacity to ions Cu²⁺, Pb²⁺and Cd²⁺ reaches the maximum values when the adsorption time is 180 min. Net adsorption to ions Cu²⁺, Pb²⁺and Cd²⁺ increases with increasing the initial concentration of the metal ions. Analysis results of adsorption dynamics show that the adsorption of Cu²⁺, Pb²⁺and Cd²⁺ follows Ho 's Pseudo second-order kinetics linear model. It can be seen from the adsorption isothermal research that absorption of the carboxyl bagasse hemicelluloses to ions Cu²⁺, Pb²⁺and Cd²⁺ can be well described by the Langmuir isotherm linear model. Moreover, the theoretical values of the maximum absorption capacity qmax for ions Cu²⁺, Pb²⁺and Cd²⁺ were determined to be 20.28 mg/g, 82.64 mg/g and 30.58 mg/g, respectively.

Abstract: A three-dimensional Computer Aided Design (CAD) model of the mould clamping board is established by Pro/E software. The ViewCast program is utilized to study casting processes of solidification and mould-filling in order to design the risers and optimize the casting technology. Based on the solidification simulation, the casting defects such as shrinkage and porosity are forecasted visually in diagrams with the help of ViewCast. Reasonable risers are designed on the basis of the solidification simulation. The mould-filling simulation verify the metal fluid gates the mould smoothly and reposefully. The filling simulation results of initial casting scheme show that this casting technology is improper. The optimized scheme is completed through the filling simulation and a modified casting technology is obtained. The parting gating system is used to pouring the mold of clamping board. The simulation results of optimized scheme indicate that the shrinkage are eliminated effectively and the metal fluid fill the mold smoothly. Experimentally, the casting confirms that the optimized method is very useful in reducing the casting defects and improving the product quality.

Abstract: Based on the first-principle calculations, we present a study of the effect of Ca doping on the electronic properties of LiCoO₂. Studies of band structure and densities of states show that hole states, which enhance the conductivity of semiconductor appear in the valence bands of Ca-doped material due to the increase of Co⁴⁺ concentration. It is further found that the Ca doping concentration should be controlled within 10 mol% of LiCoO₂ to keep the crystalline structure unchanged. We expect this study might be helpful for synthesizing good conductivity LiCoO₂ by controlling Ca doping.

Abstract: Cu-based anode has no or little catalytic activity to reaction of precipitating carbon during using carbon-hydrogen fuel, which can avoid failure or disintegration of SOFC caused by catalytically precipitating carbon resulting from Ni-based anode. However, the melting point of CuO, that is 1148°C, is far below the sintering temperature of electrolyte which limits the use of Cu-based anode. So the property of sintering of Cu-based anode between 1050°C and 1150°C was studied by co-pressing and co-sintering Cu-based anode with electrolyte. The result shows that the diffusion of copper in the electrolyte is not apparent when the co-sintering temperature is below 1130°C. At 1140°C, the Matano plane moved to anode side and the diffusion coefficient of copper in the electrolyte is relevant to concentration of copper which is 0.543×10^-8-1.74×10^-8(cm²•s^-1) when the content of copper is 1.51%~18.7%.