concave slide

基本解释

The ejection mechanism used pin ejector to pull the plastic parts out with move slanting slide simultaneously leaving circular arc concave position.
脱模机构采用推杆推出塑件的同时带动斜滑块脱出圆弧形凹位，使脱模机构简单实用。
That far up, Evenson said, glaciers tend to be concave, allowing rocks to slide far along their surfaces. Lower down, the glaciers are more likely to be convex, trapping rocks near the edges.
最后，他说道，岩石肯定落到了融化速度快过结冰速度的冰川区域之上的某处，冰川上部往往是凹陷的，这使得岩石可以沿着表面一直滑落很远，而冰川较低处凸出的可能性更大，使得岩石在接近边缘处停止滑落。