Advanced Materials Research Vols. 347-353

Abstract: Surface treatment of TiAl alloys by the small amounts of halogens leads to the formation of the protective alumina scale. The halogens can be applied by ion techniques as well as by spraying or dipping with halogen-containing compounds. In this work the results of the oxidation in air of a Ti-47Al-6Nb alloy dipped in a fluorine-containing resin were presented. The thermal cycling runs were carried out in the temperature 900°C.

Abstract: The cathode materials 0.3Li2MnO3•0.7LiMnxNixFe(1-2x)/2O2(0.35≤x≤0.5) were synthesized via low-heating solid-state reaction method. The prepared samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), thermogravimetric analysis (TG) and differential thermal analysis (DTA), and their electrochemical performances were also investigated here. The FESEM images of samples revealed that the particle of Fe-substituted samples became smaller and size distribution got narrower compared with the materials without Fe-doping. The results showed that electrochemical properties of the material depended on the content of Fe. 0.3Li2MnO3• 0.7LiMn0.4 Ni0.4Fe2O2 maintained 99.5% of the reversible capacity after 60 cycles

Abstract: A safe lithium-ion battery system of Li4Ti5O12/LiFePO4 was prepared, the solid electrolyte interface on the surface of Li4Ti5O12 electrode and the electrochemical performances of this lithium-ion battery system were studied. XRD、SEM and EIS texts were used to analyses the solid electrolyte interface on the surface of anode electrode. The result of XRD indicates that new material does generate at the surface of Li4Ti5O12 anode electrode. The result of EIS indicates that the SEI film increased the resistance of the battery, and the resistance will decrease as the cycle time increasing.

Abstract: To develop and take advantage of wind energy resources in the South China Sea's coral reefs, the paper discussed the situation of local wind resources, typhoon, corrosion, geology, wind turbine transportation and installation problems. The analysis indicates that the South China Sea typhoon-prone, serious corrosion, bad geology will cause many difficulties to installation and use of wind turbines. Authors believe that, installing and using small wind turbine in the coral reefs is feasible, but the suitable measure of anti-typhoon, anti-corrosion, transportation, installation and maintenance must be accepted, which needs a great deal of budget support.

Abstract: With the requirement of renewable energy and sustainable development, green energy resources are more and more fashionable and focused. Among of them, small wind turbine is popular and with many customers because it has an unique feature. For the blades of the small wind turbine working under the conditions of Low-Reynolds, the air viscosity has relatively greater influence on its aerodynamic performance. This is one of the greatest difficulties to design a small wind turbine. This paper studied the aerodynamic performance of the airfoil under the Low-Reynolds and designed a blade based on the airfoil of the seagull. The CFD computational result and the analysis show that the airfoil of the seagull is suitable for the special work circumstances of the small wind turbine, and it can be used for the further design of the blades. The results may provide technical reference for the wind turbine deign.

Abstract: The influences of different catalysts added to the activated carbon were studied for reducing energy consumption and enhancing reaction selectivity while microwave irradiate activated carbon for removal of sulfur dioxide and nitrogen oxides. It was found that the addition of catalyst can lower the power of microwave needed for the same sulfur dioxide and nitrogen oxides removal efficiency to a large extent; moreover, different catalysts introduced would cause different effects, in which the zincous catalyst and manganese catalyst had more apparent catalytic effects, about 95% removal efficiency could be achieved under microwave power 420W. X-ray diffraction (XRD) was adopted to have a study of the microstructure of the activated carbon, and it is shown that some catalyst components do exist on the surface of the activated carbon

Abstract: In order to increase wind energy utilization efficiency by the optimization of the wind farm micro sitting, a method which could calculate the wind farm velocity is proposed by consideration of multi turbines wake loss and superposition. Based on the given velocity data of a wind farm, the maximal annual energy production is set as the optimal objective and the ordinates of wind turbines would be the optimal variables, micro sittings of the wind farm turbines are optimized by genetic algorithm. Layout calculation result of the optimal method is quite similar to that of other successful search method, but higher efficiency is reached, and the micro sitting layout is agreement with the regular plum-type layout. Annual energy productions are also calculated under the condition of different wind turbine number. Results show annual energy production increases with the wind turbine number increased, but the increasing trend is lower and lower. The research could provide a reference to wind farm micro-sitting.

Abstract: Wind power forecast is of great significance for power grid operation and scheduling. The effection of historical time series of output power and weather factors to wind power are considered in this paper. By use of BP neural network, an iterative forecasting model about output power time series is built. An Elman neural network forecasting model is established between numerical weather prediction data and output power. Then combining the above two forecasting models using covariance optimal combination method, a combined forecasting model for wind power is achieved so as to use all effective information of different data. The simulation experiment shows that the prediction accuracy has been improved by the combination forecast.

Abstract: Aims at the small wind generations output voltage fluctuation problems, according to the characteristics of permanent magnet synchronous generator, by the vector control methods, in MATLAB/Simulink lans established permanent magnet synchronous motor current speed 2-ring vector control simulation model. Simulation results show that, the method can improve the small wind turbine output voltage stability.

Abstract: This paper aims to investigate the soil fertility of Shunyi District’s cropland combing remote sensing and ground census data based on the Geostatistical Analyst of ArcGIS. Firstly, Landsat TM image was used to identify the spatial distribution and estimate the cropland plot area using support vector machine (SVM) classification method, and the overall classification is 91.5 % by 435 field survey points. Then, the survey indicators were added to ArcGIS such as organic matter, available P, available K, total N, soil pH, etc. After exploring the sample data for each indicator, trend surfaces were generated using the optimum prediction models after cross validation. Finally, according to the identified cropland plots, the soil quality index (SQI) was derived to map the soil fertility of the study area. The result shows that the southwestern part and northeastern corner of this district were found to be high in soil pH, which lies in between 8.2 and 8.6. Additionally, wide variability of organic matter, total N, available P and K were noted which can be due to the extent of cultivation in these areas while the change in fertility level could be due to anthropogenic influence. When considering the soil heavy metals, Zn, Fe, Cu and Mn show almost the same distribution.