Stress intensity factors for a finite plate with an inclined crack by boundary collocation

In this paper, we combine the Muskhelishvili＇s complex variable method and boundary collocation method, and choose a set of new stress function based on the stress boundary condition of crack surface, the higher precision and less computation are reached. This method is applied to calculating the stress intensity factor for a finite plate with an inclined crack. The influence of θ （the obliquity of crack） on the stress intensity factors, as well as the number of summation terms on the stress intensity factor are studied and graphically represented.     

塔板理论色谱流出曲线性质的研究

塔板理论是色谱动力学理论的重要部分。本文采用数学方法把塔板理论色谱流出曲线从离散函数形式变换为连续函数形式。在此基础上运用计算机进一步研究了塔板理论色谱流出曲线的性质。     

Study on Electrical Conductivity and Mechanical Performance of Polymeric Composite Flow Field Plates for Fuel Cell Applications

Fuel cell technology has received a great deal of attention as a candidate for an alternative power source due to its environmental benefits compared to conventional sources. Flow-field plates are one of the most important components of the Proton Exchange Membrane (PEM) and Direct Methanol (DM) fuel cells technology, which is expected to possess high electrical and thermal conductivity, low hydrogen permeability, and good mechanical performance. In this study, a systematic investigation was carried out to formulate and fabricate electrically conductive polymer composites to be used in production of flow field plates using a simple low temperature, single step moulding process. It focused on the careful selection of both materials and processing methodology. ElectroPhen^? binders, various concentrations of graphite powder and enhanced dispersion agents were employed to make composite plates with high electrical conductivity and satisfactory mechanical performance. Electrical conductivity measurements were carried out using purpose-built in-plane and through-plane electrical conductivity test kits. Flexural tests were carried out to evaluate the mechanical performance of the composites. It has been found that polymer composite flow field plates can attain the electrical conductivity and mechanical performance requirements for commercial fuel cell applications without requiring a high temperature multi-step production process.