Advanced Materials Research Vols. 347-353

Abstract: In most FEM codes, the isotropic-elastic & transversely anisotropic-elastoplastic model using Hill's yield function has been widely adopted in 3D shell elements (modified to meet the plane stress condition) and 3D solid elements. However, when the 4-node quadrilateral plane strain or axisymmetric element is used for 2D sheet metal forming simulation, the above transversely anisotropic Hill model is not available in some FEM code like Ls-Dyna. A novel approach for explicit analysis of transversely anisotropic 2D sheet metal forming using 6-component Barlat yield function is elaborated in detail in this paper, the related formula between the material anisotropic coefficients in Barlat yield function and the Lankford parameters are derived directly. Numerical 2D results obtained from the novel approach fit well with the 3D solution .

Abstract: Three kinds of calculations are used in this literature based on the calculating modes on water resources carrying capacity in my literature [2]. The different level year & different guarantee rate water resources carrying capacity of Rizhao City will be calculated by the water-using efficiency factor and environment contribution (baffled) factor of America in 2005. The different welfare level (living standard) water resources carrying capacity of Rizhao City when the water-using efficiency factor and environment contribution (baffled) factor changed and it when the pollutants receiving capacity decreases 20%. The conclusion compared to the calculation results got by the method in literature [3]. According to the water resource carrying capacity status quo of Rizhao City, the thesis puts forward with development strategy in three aspects to strengthen the water resource carrying capacity of Rizhao City: Engineering type, Structure type and Economy & technique type.

Abstract: Basing on the input-output indicators, this paper analysed the regional energy efficiency of China by DEA model. The results showed: the energy efficiency in each region of China continues to be improved, but the rising speed was slow; the difference of energy efficiency in each region was great, specifically speaking, the east was the best and the middle was better and the west was the worst; from the convergence analysis on energy efficiency, it indicated that there was a convergence trend on energy efficiency in each region of China, and the eastern and middle regions were convergence, but it was divergent in the western region.

Abstract: A mathematical model is built for the heat and mass transfer during charge and discharge in a sodium sulfur cell by coupling the electrochemical equations with the equations of species transport and heat transfer. Numerical simulation is performed for the two-dimensional axisymmetric domain of a single cell. The simulated charge-discharge characteristics agree well with the experimental data of a 650 Ah Na/S cell. The transient non-uniform distributions of the electric potential, the current density, the sodium polysulfide composition and the temperature during charge and discharge are obtained. The results show that the non-uniform distribution of the sodium polysulfide composition and current density may deteriorate the degradation of the ceramic electrolyte and the corrosion of the metal container, thus may shorten the cell life. The graphite fibers in the sulfur electrode matrix are preferably radially oriented, which is advantageous for reducing the cell resistance, for improving the rechargeability and for extending the cell life. The simulation results of the transient temperature fields provide useful guidance for the optimized thermal design so as to enhance the energy efficiency of the battery system.

Abstract: Aimed to evaluate response of ecosystem service value to land use change in coastal zone of Bohai sea in last 30years, Series satellite remote sensing images obtained in 1988, 1998 and 2007 were employed to surveyed land use change integrated field surveying,firstly.Then an unit table of ecosystem services function value of main land use type was created. The response of ecosystem service value to land use change in 13 coastal zone regions of the Bohai sea in last 30 years was assessed. The result showed: the ecosystem service value lost 60.74×108RMB in coastal zone of Bohai sea caused by land use change in last 30years. Amony the 13 coastal zone region, the ecosystem service value increased only in Yantai coastal zone region and Dalian coastal zone region, there are 0.36×108RMB and 0.20×108RMB,respectively. While the ecosystem service value reduced in 11 coastal zone regions, such as Yingkou coastal zone region, Panjin coastal zone region, Binzhou coastal zone region, et al.the total lost value is 60.30×108RMB.

Abstract: Revitalizing regional economy is one of the economic development basic strategies in our country. Finance-taxation policies, as the main macroeconomic control legal means under the conditions of market economy, play a positive and key role in revitalizing regional economy, including the development process of special economic zones, southeast coastal open, developing western regions and revitalizing northeast old industrial base etc. Taking the preferential tax to the eastern coastal areas in regional economic development, financial system of weakening the Midwest financial capability, the limited role of equalization in financial transfer payment, and tax system of widening gap in development between regions into account, the author considered that some finance-taxation policies should be carried out, such as renovating the prevailing financial system, carrying out comprehensive finance-taxation policies, normalizing transfer payment system, and strengthening preferential tax policy.

Abstract: The rise of environmental protection and the progressive exhaustion of traditional fossil energy sources have increased the interest in integrating renewable energy sources into existing power systems. The energy saving and emission reduction is of most importance. Wind energy could be one of the most promising renewable energy sources. However, the intermittency and unpredictability of wind power generation creates difficulty in control of frequency and generation scheduling. Many problems will arise in the renewable energy based hybrid power system. In this paper, a fuzzy unit commitment model including wind generators is presented. Primary energy consumption, gas emission and the risk of wind are synthetically considered. Through defining membership function, the deterministic problem is transformed into the fuzzy problem. Then it is reformulated into the nonlinear problem by means of the maximum-minimum fuzzy satisfaction. Improved Genetic Algorithms (IGA) is used to solve the fuzzy optimization problem. The simulation results of a 10-unit system demonstrate that the proposed method is feasible. It can compromise between the primary energy consumption and the risk according to the decision-maker’s will. It provides valuable information in both operational and planning problems in the future.

Abstract: The (Y,Eu)2O3 precursor prepared by microwave with ultrasonic-assisted co-precipitation is superior to the one prepared by co-precipitation of conventional approach as well as co-precipitation assisted by microwave. The effect of preparation conditions on the morphology and particle size of (Y,Eu)2O3 precursor was completely investigated in this study. The ideal conditions were optimized as 0.25M Ln3+ ions concentration, 80°C reaction temperature, 90 minutes reaction time and 0 minute ageing time. Consequently, the (Y,Eu)2O3 precursor in the needle-like shape with average size of 0.25μm in diameter was obtained. The possible mechanism was also presented.

Abstract: This paper introduces a voltage regulator controll technology using AC–chopping method (AC-PWM), and applies it to the design of energy-efficient lighting controller. The power circuit, principle, control scheme and how to design of the lighting controller are described. The lighting controller proved to be low cost, low weight, low volume, high precision of output voltage, high rate of electric energy- efficient and its output wave be sinusoid approximately.

Abstract: In order to dominate the lighting market, LED needs more electrical power to be driven for higher brightness, thereby increasing thermal power dissipation, which contributes to a high heat flux of 85W/cm² within a recent typical high power LED chip. And the junction temperature has direct influence upon the light output efficiency, device life time, emitting wavelength and reliability of LED. Therefore, effective removal of heat to maintain a safe junction temperature is the key to meet the future flux per LED requirements. Compared with other individual thermal resistances along the thermal path, thermal design for much lower packaging thermal resistance is more critical to improve the performances of LED. In this paper, major present technical researches on packaging thermal management were analyzed for high power LED, and the advantages and shortcomings of these techniques were respectively summarized. Besides, some suggestions were provided for further research in this area.