摘要：The concave die design of self-pierce riveting(SPR) is of critical importance for product quality. The optimization of concave die parameters based on orthogonal test is proposed to explore the relationship between self-pierce riveted joint quality and die parameters. There are nine independent die parameter factors in orthogonal test and each factor has 4 levels. In order to evaluate the interlock and neck thickness, we carry out numerical simulations by the software DEFORM-2D. Then, the primary and secondary factors that affect the joint quality have been found out by means of range analysis. Finally, an optimization scheme is brought forward to design concave die in SPR process, which indicates that the joint has higher quality than that of former orthogonal *** work can be extended by a detailed mechanical and fatigue analysis for the joint quality of SPR process.

摘要：Direct methanol fuel cell(DMFC)has great potential to replace the traditional battery in the field of portable power *** study investigates the operational and structural aspects of a vapor-feed semi-passive DMFC supplied with concentrated *** effectiveness of using vaporous methanol to improve the cell performance is experimentally *** indicate that there exits an optimal value of methanol concentration that favors both methanol supply and control of methanol crossover(MCO).With the increase in vaporization temperature,the cell performance can be *** on the traditional structural design,a sintered porous metal plate is further used to depress the impact of MCO so that the cell performance can be significantly improved at a relatively higher methanol *** is of great importance to enhance the energy density and operating duration for portable *** mechanisms related to the performance behaviors are discussed in detail.