The perfectly designed square-wave insures the stableness and concentration of electric arc.设计理想的方波电源，确保了电弧的稳定和集中。
The symmetric structure of oxalic acid molecule and two carboxylic group on both ends ensure the stableness of c=c doubl草酸分子属于对称结构，两端的羧基使两个碳原子稳定化。