That's the first derivative of the position versus time.

它就是位置，对时间的一阶导数。

youdao

For the first time, derivative distribution of velocity in cell is presented and some new conclusions are obtained.

首次给出了电池内的速度导数分布，得出了一些新的结论。

youdao

Some first order time derivative terms are contained in the equations.

方程中含有强迫场的一阶时间导数项。

youdao

From the looks of it ECRI takes the first principle component of these four variables and then charts the first time derivative.

FORBES: On Lakshum Achuthan and ECRI: This is Becoming Embarrassing for Everyone