One way to increase the efficiency of a high-bypass jet engine is to turn the fan into an open rotor, a bit like returning to propellers, but using two rings of stubby counter-rotating blades.

提高高旁通飞机引擎的方法之一就是把风扇变成开放式旋翼，有点回归于螺旋桨的味道，但要使用两圈粗短的反旋桨叶。

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The results show that the most significant feature of turbulent free jet is the intermittently generation, shed of elliptic vortex rings, and once they generate they shed immediately.

研究结果表明：湍流椭圆自由射流的最显著特征是椭圆涡环的间歇产生、脱落，这些涡环一旦产生立即脱落。

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Rings of jet-black earthworks were scattered across an enormous pit, an arrangement that might have been based on a blueprint from the Inferno.

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He of the classic pocket style, the effortless throwing motion, the three Super Bowl rings and enviable jet set glamour.

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Again and again Monday, Revis said that he would have loved to remain a Jet for the rest of his NFL career, and that rings true.

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