Instead of the solid block of glass of the prism in pentaprism system, here 3 simple mirrors are used to perform the same task.

面镜不一整个玻璃棱镜，3块镜子来达到相同的目的。

A method is also presented for calculating the side area and volume of critical rocks with arbitrary pentahedron as example.

以任意面为例,介绍了危石侧面积、积的计算方法。

The pentahedral bicharacteristic curve grid can be applied to investigate the thrust misalignment characteristics in a unsteady flow.

面双特徵曲线网格方法可来研究非定常流动条件下的推力偏心特性。