Advanced Materials Research Vols. 989-994

Abstract: A new model and method for incorporating the effect of protection system failures into distribution system reliability evaluation are developed this paper. Firstly, the distribution system is partitioned into zones with the auto (or non-auto) switch being the boundary; through the network equivalent approach, for each load point, three component groups are respectively formed by two types of zone-elements. Then two types of protection failures and their impacts on reliability modeling are discussed. Finally, the reliability Markov model of load point with protection failures has been developed. The test results of the samples demonstrate the practicability and validness of the method.

Abstract: A novel is based on a simplified two-diode model of photovoltaic (PV) module,which can more accurately predict the output characteristic of the solar cells I-U curve. On this basis, Aiming at promptness and stability tracking the maximum power point of the photovoltaic cells under the conditions of the constant temperature and light intensity, a novel control strategy based on sliding mode based extremum seeking control (SM-ESC) system for optimally tracking the maximum power point of the photovoltaic cells is proposed.To achieve higher control quality, an adaptive adjustment method is further presented on the basic of stabilizing conditions of SM-ESC system, avoiding complicated manually parameter adjustment.Thus photovoltaic system can quickly stabilize at the maximum power point, less volatile when tracking the optimum output curve. Simulation results show the effectiveness and validity of the control strategy and adjustment method proposed .

Abstract: The Three Gorges Reservoir as an important hydraulic project of Yangtze River, the environmental issues attracts worldwide attention, and the environmental problems of littoral wetlands of the Three Gorges Reservoir are more important aspect. Total organic carbon (TOC) content by potassium dichromate oxidation spectrophotometry of downstream the Three Gorges Reservoir in Fengjie, Kaixian, Wushan, Fengdu, Daning estuary in the five regions in soil were determined. Then the organic carbon content of the soil classification comparison, analysis of the causes of soil organic carbon content of the various main reasons for differences, soil classification: the same region, same altitude, different species; the same area, the same species, different altitudes. Finally, by calculating the content of these five regions of the average total organic carbon is about 10.43g/kg.

Abstract: For boosting public greenbelt (PG) construction level, hastening urban ecological civilization construction velocity, the optimization model and its algorithm for urban PG layout is studied. The layout optimization presupposition of urban PG is described. The bi-objective optimization model for urban PG layout is established. The optimization objectives consist of maximum consistency between PG distribution and population distribution, maximum PG area in certain region. In model constraints, budget capital investment sum for PG construction, distance tolerance threshold from each citizen’s habitation to nearest PG, sum of PG needed to be upgraded and reconstructed from grade two to grade one, minimum oxygen supply capacity from given greenbelt, maximum potential supply area of PG. Genetic algorithm (GA) is employed to solve above model, the main cycles of GA for above model are designed. Above greenbelt layout optimization model and its algorithm are validated.

Abstract: In this paper, we proposed a metamaterial polarization transformer which exhibits linear dichroism and linear conversion dichroism simultaneously. Through simulation and experiment studies in the microwave regime, it was found that only cross-polarization transmissions of x-polarized waves and co-polarization transmissions of y-polarized waves are allowed in the designed structures. As a result, the proposed metamaterials can transform any polarizations into y-polarizations with signal-to-noise ratios over 20 dB and transmissions over 0.6.

Abstract: In order to obtain stable cold plasma jet under atmospheric pressure condition, we designed a high-voltage DC power supply based on the principle of multilayer piezoelectric ceramic transformer (MPT). At the same time, we developed a cold plasma jet device that its shape is similar to the gun structure. The total weight of device, including the power supply and the generator, is less than 500 g. In the experiments of argon plasma under atmospheric pressure, current–voltage measurements show that the discharge actually appears periodically pulsed with a frequency of about 30 kHz. The discharge current has a pulse-width that is about 100 ns, while its peak value reaches about 32 mA. The maximum length of the plasma is about 3 cm. The further study showed that the discharge current pulse frequency is determined by the ion drift mechanism.

Abstract: The fault-diagnosis and recovery strategy of the electric distribution network were discussed. The procedure of the hybrid genetic – particle swarm optimization algorithm, together with a practical example, was also introduced.

Abstract: An analytical model is established to predict the seepage performance of the liner system composed of a compacted clay liner (CCL) covered by a geomembrane (GM). The contaminant of Pb²⁺ diffusing through the geomembrane is assumed to be a steady-state process. The liner systems with low leakage performance are usually utilized in the municipal solid waste landfills to prevent the contaminants of the leachate from polluting the groundwater and soil beneath the landfill. To investigate the seepage rate of the Pb²⁺ in the liner systems of the landfill considering the effects of the geomembrance, the influence of the geomembrance on the seepage performance of the liner system is studied. Parametric analyses are conducted to study the effects of the thickness of GM and the number of defects in the GM on the leakage performance of the liner system. In conclusion, some suggestions for the design of the municipal solid waste landfills are proposed based on the analyses results.

Abstract: The near-tip fields of an anti-plane crack in functionally graded piezoelectric materials (FGPMs) are investigated. To make the analysis tractable as usual, the elastic stiffness, piezoelectric parameter, and dielectric permittivity of FGPMs are assumed to be exponential functions of x parallel to the crack. The boundary conditions on crack surfaces are assumed to be the stress free and electrically impermeable. The high order crack tip stress and electric displacement fields are obtained by the eigen-expansion method. This study possesses fundamental significance as Williams’ solution to homogeneous materials.

Abstract: Contradiction between the environment and economic development have become increasingly prominent, high-carbon development model of the world economy is more difficult to maintain, low-carbon development has becomea strategic objective of all countries. Countries hold low-carbon technologies, the establishment of a green trade barriers, lack of core technology and our industry, lack of international competitiveness of exports facing enormous challenges. For this reason, the paper deeply analyzes the impact of a low-carbon economy on the international competitiveness of the industry and made a reasonable suggestions and strategies from both countries and companies on how to enhance the international competitiveness of industry.