It's a unidirectional, a one-directional flow of electrical charge.

这一种单向的、一方向的电荷流动。

What determines whether it is unidirectional or bi-directional?

什么决定单向还双向的呢？

Uh, the security camera microphone is unidirectional.

监控摄象头上的麦克风单向的。

Consequently, the cultural exchange becomes unidirectional, with visitors observing rather than participating, and assimilating only what is selectively presented.

因此，文化交流变得单向，参观者观察而参与，只吸收选择性呈现的东西。

They probably had unidirectional air flow, just like modern birds do, making them very efficient at breathing, even while flying.

们很可像现代鸟类一样具有单向气流，使们在飞行非常高效地呼吸。

This unidirectional current flow could be controlled by varying the voltage to the cathode, which makes it release more or less electrons.

这种单向电流可以通过调节施加在阴极上的电压来控制，电压的变化会促使阴极释放或多或少的电子。

One of the reasons why React was so successful is because it took that unidirectional flow, brought it to the front end.

React之所以如此成功的原因之一在于，采用这种单向数据流的理念，并将其引入到前端开发中。