The solution of the projection on inward concave compositionsurface of cylinder and cone is discussed. and the critical point on the projection is calculated with analytical method.
本文着重介绍内凹的圆柱和圆锥组合面上落影的求法，并尝试利用解析的方法，求出落影上的特殊点。
2
That's why MESSENGER is loaded with instruments to determine the surfacecomposition.
这就是为什么信使装着工具，以确定它的表面组成。
3
New Horizons' infrared observations may provide insight into the composition of the moon's surface and interior.