Advanced Materials Research Vols. 347-353

Abstract: LiNixMn2-xO4 (x=0, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5) compounds with spinel crystal structure are synthesized by sol-gel method. The dependence of the physicochemical properties of these compounds has been extensively investigated by using X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammogram (CV) and charge-discharge test. It is found that as Mn is replaced by Ni, the initial capacity decreases, but the capacity retention is enhanced. Of all the LiNixMn2-xO4 (x=0, 0.05, 0.1, 0.2, 0.3, 0.4) compounds, the LiNi0.2Mn1.8O4 has best electrochemical performance, about 120mAhg-1 discharge capacity, its capacity retention rate of 96.6% after 100 cycles. However the LiNi0.5Mn1.5O4 sample shows excellent electrochemical performance at 4.7 V high potential, 150 mAhg-1 discharge capacity, above 110 mAhg-1 of capacity retention after 42 cycles of charge/discharge. The prepared LiNi0.5Mn1.5O4 powders sintered at 750 °C here has Fd3m space group.

Abstract: Article introduces the gray prediction GM (1,1) and the modeling process that first proposed by Professor Deng Julong. The system analyzes its advantages and disadvantages. With the development of electricity market, the importance of load forecasting is becoming increasingly obvious. An increasing demand for the accuracy of load forecasting is significant. The result traditional forecasting predicts has reference value and the method is mature. But some improvement is needed to improve prediction accuracy.

Abstract: Through the application research of expert system shell ESTA, We have established a transformer condition evaluation expert system(ES) based on ESTA and corporate standards of State Grid (Q/GDW 169-2008) «Guide forCondition Evaluation of Oil-immersed Power Transformers (Reactors) ». Knowledge Base consists of several sections, parameters, rules in the evaluation of state variables, components and transformers. The value of the transformer condition evaluation expert system is that it supports and enhances the operation and maintenance personnel work, guidance (less experienced) the operation and maintenance personnel to understand the basic process of transformer condition evaluation. The application show that the system is effective and practical.

Abstract: Luminous efficiency of high power white light LED (light emitting diode) at different temperature and driver current is measured with the photometric, chromatic and electric characteristics analyzer. It is shown that the luminous efficiency decreases as the temperature and (or) the driver current increases. The highter the driver current is, the more strongly temperature worsens the efficiency. However, the changing rate of efficiency with current is similar at different temperature. At last, a luminous efficiency model with temperature and current is constructed. This research is very important for the design of energy-saving LED lamps.

Abstract: Airborne DC converter is the most important secondary aircraft power conversion equipment, analysis of some Airborne DC-DC converter's working mechanism, according to the actual requirements of the system design the converter main circuit. Meanwhile, calculated the logic test circuit parameters, build a simulation model of Airborne DC converter with the saber software, simulated and tested the system, simulation results show that the system design come to the corresponding functional requirements, and finally optimized the system using the results of simulation, and ultimately make the system more reasonable, for the future design of airborne converter provides a useful reference.

Abstract: The computational fluid dynamics analysis of a small vertical axis wind turbine with ball-shaped blades has been done in this paper. First, a three-dimensioned model of the wind turbine with the ball-shaped blades has been constructed by using the software of FLUENT 6.3. Then, by giving the size parameters and shape parameters of the blades, the simulation has been done and the corresponding simulation results have been obtained. The contuours of static pressure around the wind blade area has been shown. The simulated model and the results can be used for finding the factors which will affect the power efficiency of this type of wind turbine in the future. Finally, the simulation results of the blade with zero curvature radius and curvature radius of 2 are shown and compared in order to demonstrate the effectiveness of this computational fluid dynamics analysis method. It can be concluded that the blades with curvature of 2 can obtain more toruqe comparing with the zero one and it would be the more suitable option in the blade design.

Abstract: This paper introduces the fiber filter device by adjusting the charge and discharge water to adjust the fiber density - filter accuracy, interception capacity, filtration resistance and other parameters. In the industrial, commercial market prospects, environmental, economic and social benefit is remarkable.

Abstract: The relationship between CO2 emission and economic growth of Shanghai is discussed, which is realized in the way of mutual study of the cointegrating analysis of GDP, energy consumption and CO2 emission from 1993 to 2009 of Shanghai and the study of causality based on VECM. As can be seen from the conclusion, in the long run, the relationship between the economic growth and CO2 emission of Shanghai is unidirectional, i.e., the growth of economy will promote the quantity of emitted CO2.However, CO2 emission is not the Granger cause of economic growth. But in the short run, they constitute no cause-and-effect relationship. Therefore, some suggestions regarding the energy conservation and emission reduction policies of Shanghai are presented based on an empirical analysis.

Abstract: This paper selected 16 cities of the Yangtze River Delta as research objects, using 5 economic indicators, namely economic aggregate, economic structure, degree of openness, infrastructure construction and sustainable development to set up an evaluation index system. Based on the otherness of the evaluation index, this paper uses the entropy weight method to assess the weights impersonally. By means of TOPSIS method, this paper evaluates and compares the integrated power of economic development in “the Yangtze River Delta” economic circle.

Abstract: The structure of vertical axis wind turbine with wind speed-adapting is based on Darrieus straight-bladed turbine. It features that its blades are composed of movable and fixed blades. Through the opening and closing of the movable blades to adapt to the wind speed automatically, the turbine not only can start up in low wind speed, but also realize the conversion from drag-mode to lift-mode. Due to the special structure, the aerodynamic model of this turbine in drag-mode is different from that of Savonius and Darrieus turbine. So in this article, the aerodynamic model of this turbine in drag-mode is established. Then the coefficient of start-up torque is calculated and compared with that of Darrieus straight-bladed turbine which has the same size. The results show that the start-up performance of this turbine is obviously better than that of Darrieus straight-bladed turbine.