中文摘要：

一般认为范氏气体方程在大体积极限下和理想气体状态方程一样．不过理想气体还要求满足焦耳定律等，也就是内能对体积的偏导数为零．由于内能对体积的偏导数可以化为物态方程的一阶导数，是否能在状态方程一阶导数这一层次上也要求范氏方程的大体积极限和理想气体一致就值得探讨．结果表明：如果在一阶导数层次上比较，范氏气体方程在大体积极限下不能再回复到理想气体．推广范氏方程让范氏系数依赖于温度，可以得到实际气体在大体积极限下的一个渐近形式．

英文摘要：

It is well-known that van der Waals equation of state goes over to that for the ideal gas in the limit of large volume, but whether the first derivative of it also works is a problem without explicitly explored hitherto. The exploration shows that the further requirement on the real gas as it in the limit of large volume can reproduce the ideal gas in sense of the first derivative is inappropriate unless asymptotically.