closed tube是什么意思

用法例句

The paper introduces closed management of slab yard and some work having been done such as enriching the varieties of charging and optimizing the structure of charging.

介绍了电炉厂在废钢场地封闭管理,丰富炉料品种和优化炉料结构等方面所做的工作,证实了精料方针能显著改善技经指标。