The flight phase: As an athlete moves through the air, his leg swings backward and then moves rapidly forward.

腾空阶段：当运动员在空中移动之时，他的腿先向后摆动，然后迅速向前移动。

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So, the action of extending the leg backward creates a forward and upward movement (the flight phase).

因此，腿向后伸展的作用力，产生一个向前向上的运动(腾空阶段)。

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Two phase countercurrent flow in reactor hot leg at loss of coolant accident is studied by experiment and analysis.

对反应堆失水事故条件下热管段内的两相流逆向流动过程进行了实验研究和理论分析。

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Genzyme is itself involved in a European 300-patient phase II trial that attempts to use skeletal muscle cells from the leg to prevent heart failure.

FORBES: Small Stem Cells Find Big Backers