变量变化法
the variable transformation
质量变化规律
quality change rule
quality changes rule
the law of quality variability
变质量起落部分
changed mass elevating parts
变质量完整系统
variable mass holonomic system
变质量运动
movement with different mass
变质量热力学
variable-mass thermodynamics
变质量力学系统
variable mass mechanical system
转动变质量系统
rotational variable mass system
变质量弹性系统
variable mass-point elastic system