0 a change in a situation that is much bigger than usual -- 阶跃变化，步进变化（在某一局势下，比常规大得多的变化）
There is a step change taking place in communications technology. 通讯技术取得了较大的变化。
The step change determines the initial state for the postimpact motion.
The step change in angular speed is about -0.75 rad/s.
Finally, we explored how a step change in density at the base of the constant gradient region influenced the thermal.
Second, we determined the fraction of the thermal that penetrated an elevated inversion (step change in density) above a neutral surface layer.
As a cursory investigation of this problem, two sets of experiments were conducted with a step change in density at the base of the gradient.
For two populations of cells responding more transiently to a step change, a similar cancellation would require higher reversal frequencies.
Similarly, after the step change back to the flat plate, the regrowth in the skin friction may signal another reorientation of the new structures formed a t the wall.
Given the relatively large size of the stress bore after only 36, of recovery, it is clear that some extremely energetic mixing must occur following the step change in curvature.
