It may be flat, concave, and convex or any one of a great variety of shapes to promote turbulence or help control combustion.
活塞顶部可以做成平的、凹的、凸的或是能够促进涡流帮助燃烧的任何形状。
2
Various lines and shapes show planes of light reflections to the viewer. Convex and concave areas make for exciting shapes. Realistic design should look like a natural object.
各个线条及面对观察者显示多个反光面，凹面或凸面用于令人激动的形状，应该象个自然物体。
3
The diaphragm is formed to make maximum a difference in air pressure of the front surface and the rear surface of the diaphragm, thereby forming any one of concave and convex shapes thereof.