urea clathration

例句：

1. 1. Urea crystallization is a process where urea is converted into solid urea crystals.
   尿素结晶是一个将尿素转化为固体尿素晶体的过程。
2. 2. During the urea crystallization process, the temperature and pressure must be carefully controlled to prevent contamination.
   在尿素结晶过程中，必须小心控制温度和压力以防止污染。
3. 3.The urea crystallization process is used in agriculture to improve soil fertility.
   尿素结晶过程用于农业以提高土壤肥力。