Advanced Materials Research Vols. 1049-1050

Abstract: Frequency selective surface (FSS) is a two-dimensional periodic structure. It exhibits total reflection and transmission in the neighborhood of the element resonances. As it performs as a filter, FSS is widely used in the fields of microwave and optics. In this paper, the finite element method is used to analysis frequency selective surface and study on the feasibility of Ansoft HFSS software for frequency selective surface simulation. Hexagonal element of frequency selective surface is as an example to explore the simulation method and the process of Ansoft HFSS. Through the comparison of the simulation curves and the measured curves of hexagonal element frequency selective surface film by photoetching technology, the simulation method of Ansoft HFSS software for frequency selective surface is correct. At the same time, this paper further verified the reliability of the simulation through the example of the ring and the cross unit structure.

Abstract: Power line communication (PLC) has received much attention recently because of the need of reliable and automatic metering, In this paper we present a comprehensive study over the use of PLC in China. We begin with some background including the distribution grid topology, the power line channel environments, and the deployment of PLC network. Then we show some field test results of PLC-based meter-reading in a high frequency band. In addition, a suggestion how to improve G3-PLC is presented which can adapt China grid better.

Abstract: Off-grid systems are proposed for the power shortage in remote areas. In an off-grid home, electronic devices can result in poor power quality issues. In this paper, two topologies of off-grid systems are presented and compared to chose more suitable one for an off-grid home. One compared topology is a system with inverter and transformer, and another one with the converter and inverter. We compared and examined their corresponding current, voltage waveforms, and the THD values based on the same power source and load by the Matlab/Simulink software. The simulation results show that the system with inverter and transformer is more suitable for off-grid home in remote areas.

Abstract: Dust particles and organic contaminants in environment can intrude into electronic device interior through the shell and opening holes. The intrusive contaminants can adhere on electric contact interface. Therefore, it can reduce components’ electric connection reliability. Widely it used acoustic dust-proof mesh to protect the mobile phone and other electric devices’ earpieces and speakers from contamination intrusion. This preventing contamination role makes much dust particles and organics adhere on the mesh. It is necessary to evaluate dust-proof mesh ability against contamination. In this paper, actual field contaminated meshes have been taken failure analysis. Then, lab simulation experiments have been established with considering meshes and contaminants’ characters. Finally the influence of mesh’s parameter on contamination has been researched.

Abstract: A novel approach was performed to eliminate the expensive proton exchange membrane (PEM) from the direct formic acid fuel cell (DFAFC). In the new designed PEM-free direct formic acid self-electrolyte fuel cell (SEFC), formic acid performed the functions of both fuel and ion conductor because of it can be ionized in the aqueous solution. Porous PTFE film was used as the separator in the SEFC to isolate the electron transport inside the fuel cell. This acidic SEFC utilizing Pt as anodic/cathodic catalysts can achieve a power density greater than 1.0 mW cm^–2, which was about 1/5 of that of a traditionally PEM-equipped DFAFC with the same catalysts, after the optimization of thickness and porosity of the porous PTFE film.

Abstract: The cooling of proton exchange membranes fuel cell (PEMFC) is one of the crucial components in the heat management of a fuel cell. This paper presents three cooling channels of PEMFC: linear, serpentine and heat pipe. The cooling geometric models are proposed for the three cooling channels, respectively, and the corresponding temperature distributed diagrams are derived under steady state by SINDA/FLUINT. From the simulation, the linear cooling channel of PEMFC renders local overheating inside the cell under the same conditions, obviously. It is also observed that the serpentine cooling channel ensures the uniformity of cell temperature, whereas the change of channel diameter is not able to adjust the radiating performance effectively. Extensive simulation results show that the heat pipe cooling channel not only outperforms the other cooling channels in radiating performance, but also provides a remarkable environmental factor.

Abstract: The keys for development of copper-based chalcogenide crystal thin film solar cells are to improve efficiency and reduce costs. Oriented growth and band gap grading of its absorption layer crystal film are important ways to improve the efficiency. It proposed controllable preparation of this type thin film by chemical solution deposition and co-reduction, and study on the crystal orientation and regulation of the band gap gradient. It will design the composition and band gap gradient of multi-component and multilayer films, and establish the models for design, theoretical calculation and performance prediction; It will explore the effect of band gap gradient on electrical and optical properties and reveal the effecting laws and mechanism on electrical and optical properties.

Abstract: Based on IR2103S half-bridge drive chip, high-power wide voltage DC motor drive circuit is successfully designed. This paper analyses high power wide voltage DC motor drive control principle, H-bridge drive principle, control characteristics of MOSFET and drive method, moreover, this paper also introduces operating characteristics of wide voltage IR2103S half-bridge drive chip and its control logic and operation modes, in addition, it provides interface method for connecting IR2103S chip and single-chip microcomputer, and measures to control high-power wide voltage DC motor by the single-chip microcomputer.

Abstract: Aiming at the current widespread present situation of that the design and manufacturing of the construction machinery will lead to many adverse effects on the environment and resources In the whole life cycle,We explored the method of the green design and manufacturing for the Construction machinery the selection of green materials and some green manufacturing technology These new technology are used to improve the resource utilization rate, lower costs, reduce environmental pollution, face with the challenges of the international green trade barriers and carry out the strategy of sustainable evelopment in the manufacturing.

Abstract: The aim of this study was to obtain the method of the green design and modular design that oriented construction machinery products. A variety of modern design tools such as the finite element analysis software package and optimize design package and a two-factor evaluation fuzzy modelare used to analyze and Evaluation the green degree and the module degree of the construction machinery. Some modern mathematical tools such as AHP and fuzzy comprehensive evaluation method are used to calculate and evaluate the green degree and the module degree in construction machinery design. The proposed design method can meet the requirements of the green degree and the module degree of the construction machinery.