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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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.

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一种三角形俄国乐器，有三根弦，发出类似于曼陀林琴的声音。

Russian instrument with a triangular body and three strings that produces sounds similar to those of a mandolin.

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