改进型无限冷硬铸铁
modified infinitely chilled cast iron
凸焊机
projection welder
projection welding machine
凸焊工艺
projection welding process
Projection welding technology
凸函数次梯度
subgradient of convex function
凸函数
convex functions
geometric convex function
convex function
convex
concave function
convex cone