In the standard reference equation of state for the thermodynamic properties of water, known as IAPWS-95, the fourth virial coefficient D(T) becomes abnormally large in magnitude at temperatures below approximately 300 K. At conditions where a virial expansion using only second and third virial coefficients should be essentially exact (such as vapors at pressures near 100 Pa or 1000 Pa), such a truncated expansion may miss on the order of 2 % of the deviation from ideal-gas behavior in the compressibility factor or the fugacity. The term in IAPWS-95 that causes this issue is identified, and suggestions are made for future equation-of-state development.

中文翻译：

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IAPWS-95在低温下的病毒膨胀异常

在水的热力学性质的标准参考状态方程（称为 IAPWS-95）中，第四维里系数 D(T) 在温度低于约 300 K 时变得异常大。第三维里系数应该基本准确（例如压力接近 100 Pa 或 1000 Pa 的蒸汽），这种截断的膨胀可能会错过压缩系数或逸度与理想气体行为偏差的 2% 数量级。确定了 IAPWS-95 中导致此问题的术语，并为未来的状态方程发展提出了建议。