“外旋”用英语怎么说？

他研究了摆线 、 圆外旋轮线和四点圆的旋轮线的几何性质.He investigates geometrical properties of cycloids , epicycloids, and hypocycloids.而在答应出现动力性外旋时则出现了更明显的滞后现象.Hysteresis was significantly greater when dynamic external rotation was allowed to o...