The upper and lower rings have opposite charges, which allow the motor to contract and release, alternately tugging at the DNA like a ring of hands pulling on a rope.

高环和低环具有相反的电荷，这样的特性可以使其像拉绳子的两只手一样交替地拉住DNA。

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The contract states between the stator and the rotator of traditional ring type traveling wave USM is dynamic point-area contract, which lead to low output torque.

传统的圆环型行波超声电机定转子之间的接触状态为动态的点面接触，造成其输出力矩低。

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Those who find themselves in demand by name designers and the editors of Vogue may or may not ever snag the brass ring--a multiyear (two to five years) contract with a clothing or cosmetics company.

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