And what we'll discover is that when we allow the gas to expand reversibly, we get the most work. This is neat.

最后将发现,当气体可逆膨胀的时候，对外做功最大。

麻省理工公开课 - 热力学与动力学课程节选

The purpose here is to look at a series of processes in which temperature is held constant, and we're going to calculate how much work we get from allowing a gas to expand under various conditions.

目的是让大家了解一下,几个保持温度不变的过程，然后我们将计算,气体在不同膨胀过程中,的对外做功。

麻省理工公开课 - 热力学与动力学课程节选

And here, in an isothermal expansion, The bath is putting back the energy that the gas is expanding or using to expand, and so the energy is flowing back into the gas through the environment in the isothermal expansion.

而在等温膨胀中，恒温环境将气体膨胀对外做功,而损失的能量又返还回来，在等温膨胀中,能量从环境,流向系统。

麻省理工公开课 - 热力学与动力学课程节选