PFC 代码语法解析：Cundall 等人在 1970 年代提出的粒子流代码

这句话语法上是正确的，但可以通过添加动词使其成为完整的句子。以下是一种方法：

'The particle flow code (PFC), which was proposed by Cundall et al. [25] in the 1970s, is based on the discrete element method.'