本文研究了自由翼的翼型的几何特征，表明它们的中弧线都具有反折的特点；
The geometry of airfoils, which is proper for the free-wings, was numerically investigated and the results indicated that the airfoils must be featured by the S-shaped camber.
一年生草本茎外倾或直立，30-90厘米高，分枝，具棱，具稀的反折的皮刺沿着棱。
Herbs annual. Stems decumbent or erect, 30-90 cm tall, branched, angulate , with sparse retrorse prickles along angles.
焦点之间的中点为中心。椭圆的一个特性是：连自一个焦点的直线边界反折会通过另一个焦点。
The flatter the ellipse, the farther apart are the foci, and the farther each focus is from the center .
第二，如果字符串用一行表示太长，您可以使用Python连续字符：反斜线 (\) 来对字符串进行折行。
Second, if a string is too long for a single line, you can wrap the string using the Python continuation character: the backslash (\).
在折反系统中，用同一种红外材料实现了像差特别是二级光谱的校正。
In the catadioptric infrared optical system, both aberration and second spectrum are corrected by using the same infrared optical material.
在折反系统中，用同一种红外材料实现了像差特别是二级光谱的校正。
In the catadioptric infrared optical system, both aberration and second spectrum are corrected by using the same infrared optical material.
应用推荐