Mr.Obama is said to have declared that the United States and Cuba are "on a path of change", while reminding his fellow heads of state that the democratic process that brought them into office does not exist in Cuba.

VOA: standard.2009.04.18

If you have a quantity which is constant over any closed path, that quantity is a thermodynamics state function.

如果有一个物理量,对任何闭合回路积分是常数，这个物理量就是一个热力学态函数。

麻省理工公开课 - 热力学与动力学课程节选

All right, so I need to tell you the path, when I go from one state to the other.

好，当我从一个状态过渡到另一个状态时，我需要告诉你们路径。

麻省理工公开课 - 热力学与动力学课程节选

The amount of work you've put in to get here depends on the path. It's not a function of state.

这些量就能,决定系统的状态了。

麻省理工公开课 - 热力学与动力学课程节选

So the system will not be described by a single state variable during the path.

因此系统将不能被,路径上的单一状态变量描述。

麻省理工公开课 - 热力学与动力学课程节选

Now remember, we went through before how it's a state function but to calculate it, you'd need to find a reversible path, along which you can figure this out.

请记住，我们不需要知道它是怎样的一个态函数,只计算就可以了，你需要找到一条可逆路径，沿着这条路径就能算得这个结果。

麻省理工公开课 - 热力学与动力学课程节选

The sum of path number 2 and path number 3 get me to the same place, so the energy change by going through this time path, this intermediate point here back all the way to final state should be the same the red path.

而经过路径2和3可以3,到达同样的末态，因此经过路径,2和3带来的能量的变化，与路径1带来的,能量变化相同。

麻省理工公开课 - 热力学与动力学课程节选