平面图的

1.The shape of cross-section is an ellipse folded in half through one symmetry axis, and the axis keeps perpendicular with pinacoid-view.

断形状为沿对称对折的椭圆，此对称始终垂直于截，其方向平图上的流道中线无关。

2.In this paper, we study the minimum-weight feedback vertex set problem in outerplanar graphs and present a linear time algorithm to solve it.

本文主要考虑外平图中的反馈点集并给了一个求外平图最小顶点赋权反馈点集的线性时间算法。

3.The drawing method for the double channel impeller is studied.It is found that there is an in-conformity between the dimensions of plane-view and pinacoid-view of fluid cross-section.

摘要研究了双流道污水泵叶轮常用的图纸表达方法，发现平图上的断投影结果图中确定的断形状尺寸不一致的问题。