研究了三角形周长平分弦的性质，得出任一三角形均可确定其最长和最短周长平分弦。
Discuss the properties of the perimeter bisection chord of a triangle, give any triangle, its longest and shortest bisection chords can be determined.
基于扇翼机的飞行原理，提出通过改变攻角以及增加尾部升力面弦长的方式提高气动效率，进而实现垂直升降的方法。
Based on the principle of flight of fan wing aircraft, realizing methods of VTOL are preposed by changing the Angle of attack and increasing chord length of the tail.
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