Correlation between Atomic Size Ratio and Poisson＇s Ratio in Metallic Glasses

We report the correlation between atomic size ratio and Poisson＇s ratio in various metallic glasses. It is found that atomic size ratio has an influence on the atomic packing density of metallic glasses, which would significantly impact the shear modulus rather than bulk modulus. The findings may be helpful for understanding the structural origin of Poisson＇s ratio in metallic glasses, and are instructive for designing tough metallic glasses with large Poisson ＇s ratio.     

碱促进剂在Ru/CNFs催化山梨醇氢解制备二元醇中的作用

研究了NaOH,KOH,Mg（OH）₂,Ba（OH）₂和CaO等5碱促进剂在Ru/CNFs催化山梨醇氢解过程中的作用机制.结果表明,这些碱均能显著提高山梨醇的转化率,但生成二元醇的选择性随碱种类而有所差异,其中以CaO促进的催化剂二元醇选择性最高.CaO提供了用以催化C—C键断裂的OH^-,同时与中间产物形成络合物从而影响反应历程.提出了CaO作为促进剂时山梨醇氢解生成二元醇的反应历程,并由此进一步优化了山梨醇浓度、Ru催化剂用量和碱促进剂用量之间的匹配以达到更高的二元醇产率.