rate of increment

The ratio of df to dt is called the rate of increment of function f.

函数f的增加量df与时间的增加量dt之比称为函数f的增加率,而非变化率。

The paper first gives the statistics data on the percentage of the subsystems mass to satellite dry mass and qualitative influence of design lifetime on the subsystems,puts emphasis on quantitative analysis of the effects of design lifetime on the design parameters and mass of the subsystems,and then gives the subsystems mass,mass penalty and percent mass penalty as a function of design lifetime.

首先给出了卫星各分系统质量(mass)在整星干重中所占比例的统计数据及设计寿命对分系统的定性影响;重点定量分析了设计寿命对各分系统设计参数及质量的影响,给出诸分系统的质量、质量增加、质量增加率与设计寿命的关系曲线;最后分析并给出卫星干重及总质量与设计寿命的关系,指出设计寿命的延长是以质量增加和成本上升为代价的,应综合考虑设计寿命与成本。