标准椭圆方程
standard elliptic equation
标准椭圆封头
standard elliptical dished head
standard elliptical head
standard ellipsoidal head
standardellipsoidal head
ellipsoidal head
非标准椭圆封头
non-standard elliptical head
半椭圆形弹簧
semi elliptic spring
half elliptic spring
semi-elliptical spring
half-elliptic spring
half-elliptic spring(semi-elliptic spring
半椭圆形垄
ridge of half ellipse shape