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.
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.
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