在经典系统中，当自由粒子所处的体积发生膨胀时，总是会对外界输出正功；然而，在相同条件下，量子系统的体积膨胀并不一定输出正功，这取决于膨胀的速度．本文探讨了无限深势阱壁在有限匀速膨胀过程中对外输出功的特性．计算结果表明，势阱壁移动速度越快，总的输出功越小．

 In classical systems, when the volume occupied by a free particle expands, positive work is always done on the surroundings. However, under the same conditions, the expansion of a quantum system does not necessarily result in positive work; this depends on the speed of the expansion. This paper explores the characteristics of the work output during the finite uniform expansion of the walls of an infinite potential well. The calculations show that the faster the walls of the potential well move, the smaller the total work output.