Reaction pathway analysis was carried out to investigate the activation energy barriers of Shockley partial dislocation mobility in 3C-SiC. For each partial dislocation, there are two types of dislocations according to which kind of atom, Si or C, comprises the core edge of the dislocation line. In this paper, the partial dislocation is simulated by Vashishta potential functions. Moreover, the activation energy of kink pair nucleation and kink migration are investigated by reaction pathway analysis. The dependence of the activation energy on the driving shear stress is also discussed. The results show that during kink migration, 30° partial dislocations have a lower activation energy barrier than 90° partial dislocation. And, C-core partial dislocations have a higher activation energy barrier than Si-core dislocations for both degrees of partial dislocations during kink migration and nucleation. This conclusion is consistent with the experimental result that Si-core dislocations migrate more readily than C-core dislocations. Furthermore, we found that partial dislocations with larger distance between the dangling bond atoms along the dislocation line have higher activation energy barriers. Based our calculation results, we propose new models to account for the morphological differences in the dislocation lines.
In a sodium-cooled fast reactor (SFR), liquid sodium is used as a heat transfer fluid because of its excellent heat transport capability. On the other hand, it has strong chemical reactivity with water vapor. One of the design basis accidents of the SFR is the water leakage into the liquid sodium flow by a breach of heat transfer tubes in a steam generator. Therefore the study on sodium-water chemical reactions is of paramount importance for safety reasons. This study aims to clarify the sodium-water reaction mechanisms using laser diagnostics. The sodium-water counter-flow reactions were measured using laser diagnostics such as laser induced fluorescence, CARS, Raman scattering and photo-fragmentation. The measurement results show that the sodium-water reaction proceeds mainly by the reaction Na H 2 O NaOH H and the main product is NaOH in this reaction. Its forward and backward reaction rates tend to balance with each other and the whole reaction rate reduces as temperature increases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.