稀土变质剂对中碳马氏体铸钢中夹杂的影响

通过光镜、扫描电镜、电子探针、俄歇能谱等手段,研究了稀土变质剂对中碳马氏体铸钢中夹杂的变质作用,并研究了夹杂的化学组成,结果表明,稀土变质剂改善了中碳马氏体铸钢中夹杂的形态、大小及分布。稀土作为表面活性元素,富集在硫化物、氧化物夹杂周围,形成复合夹杂,且阻止夹杂长大,从而使夹杂变得圆整细小,分布均匀,削弱了夹杂对钢的有害作用,提高了中碳马氏体铸钢的力学性能,特别是冲击韧性。

Stochastic calculus for Markov processes associated with non-symmetric Dirichlet forms

Nakao＇s stochastic integrals for continuous additive functionals of zero energy are extended from the symmetric Dirichlet forms setting to the non-symmetric Dirichlet forms setting. ItS＇s formula in terms of the extended stochastic integrals is obtained.