齿轮轮齿接触印痕
gear tooth contact pattern
发动机飞轮齿轮箱
engine flywheel gear case
复合轮齿齿轮副
complex wheel teeth gear set
小齿轮轮齿啮合
pinion gear tooth contact
小齿轮轮齿啮合型式
pinion tooth contact pattern
超声辅助助剂提取技术
ultrasounic extraction technology
沉箱辅助安装
assistant caisson installation