isothermal heat treatment

例句：

1. 1. The temperature of the liquid was maintained at a constant level throughout the experiment.
   实验中，液体的温度在整个过程中保持不变。
2. 2. The process of heat transfer is isothermal in nature.
   热量传递的过程是等温的。
3. 3. The material undergoes a phase transition at an isothermal point.
   该材料在等温点发生相变。