Step Structure in Cold-Rolled Deformed Nanocrystalline Nickel

The microstructure characteristic of the cold-rolled deformed nanocrystalline nickel metal is studied by transmission electron microscopy. The results show that there are step structures nearby the grain boundary （CB）, and the contrast of stress field in front of the step corresponds to the step in the shape. It is indicated that the interaction between twins and dislocations is not a necessary condition to realizing the deformation. In the later stage of the deformation when the grain size becomes about lOOnm, the deformation can depend upon the moving of the boundary of the stack faults （SFs） which result from the partial dislocations emitted from CBs. However, when the size of SFs grows up, the local internal stress which is in front of the step gradually becomes higher. When this stress reaches a critical value which stops the gliding of the partial dislocations, the SFs will stop to grow up and leave a step structure behind.     

电化学二氧化碳还原中的铜基催化剂

由于不断增加的二氧化碳排放导致全球变暖,且能源短缺等问题日益恶化,将二氧化碳电化学还原为高附加值化学品和燃料引起了极大的兴趣,设计高效催化剂对实现二氧化碳的高效选择性转化具有重要意义. 在所探索的各种催化剂中,铜基催化剂具有良好的开发潜力,可用于烃类生产. 本文综述了铜基电化学二氧化碳转化材料的最新进展. 分别从尺寸结构到不同形式（合金、氧化物）的铜基催化剂,以及分子催化剂等方面展开,重点讨论铜基催化剂上二氧化碳电解还原的反应机理. 最后,对未来高效铜基催化剂的设计提出展望,以促进二氧化碳转化的可持续发展.