noiselessly

The piston slides noiselessly up and down.

这个活塞上下活动，没有响声。

The traditional transformer is trending towards pocketsize and noiselessly in inverter using high-frequency link technique,but the control circuit becomes difficult to be designed.

高频链技术使逆变器中变压器趋向于型、无噪声化,但增加了控制电路的设计难度。