The system can be an open system, or it can be a closed system, or it can be isolated.

系统可以是开系，可以是闭系，或是孤立系。

麻省理工公开课 - 热力学与动力学课程节选

We don't say anything about implicitly here, we're talking about a closed system, so there's no mass leaving the system.

我们不讨论,这是隐含条件，因为我们讨论的是孤立系统，因此系统没有物质流失。

麻省理工公开课 - 热力学与动力学课程节选

The closed system allows energy to transfer through the boundary but not mass.

闭系允许能量通过它的边界传递,但质量不行。

麻省理工公开课 - 热力学与动力学课程节选

So a closed system would be, for instance, a glass of ice water with an ice cube in it, with the lid on top.

因此闭系可以是，比如说，一杯放了,一个冰块的冰水，顶上加了盖子。

麻省理工公开课 - 热力学与动力学课程节选