scrobicular ring

• 凹环

scrobicular ring的用法和样例：

例句

1. The sectorial different-color filters are stuck sequentially on the upper surface of motor casing to form a ring.
   另外，一圆环状遮片以其中央开孔套固于转轴上，并与滤光片保持一空隙，遮片的外侧面另外挖设凹环。