等温等压不可逆相变过程和非等温等压不可逆相变过程状态函数增量可以通过设计途径法求算 ,所设途径中包含有与已知相变焓相应的可逆相变过程 .在标准压力下 ,通过改变温度设计途径 ;在一定温度下 ,通过改变压力设计途径 The isothermal isobaric irreversible phase change process and the non-isothermal isobaric irreversible phase change process state function increment can be calculated by the design approach method, which includes a reversible phase change process corresponding to the known phase change enthalpy, , By changing the temperature design approach; at a certain temperature, by changing the pressure design approach