下阀芯起开关作用。

The lower valve core performs a switching function.

youdao

晶体管可以说是微电子中非常重要的器件，它最主要的功能是电流放大和开关作用。

Transistor is viewed as a very important amplification and switching device in micro-electric field.

youdao

进出水口有二个单向阀，水箱内置有浮球装置，该装置和二个单向阀共同起开关作用；

There are two one-way valves for water inlet and outlet, which cooperates with floating ball in water tank to play switch role.

youdao

Now, it's more complicated than that because it's not just sodium channels that are involved, there are potassium channels also, and the interplay between sodium channels opening and potassium channels opening, this is described in some detail in your book.

现在 事情更复杂了,因为这一过程不仅关系着钠离子通道,也关系着钾离子通道,以及钠离子通道和钾离子通道之间开关,的相互作用,书中有详细解释

耶鲁公开课 - 生物医学工程探索课程节选