核心素养的提出表示国家越来越重视学生能力的培养,而不是单纯给学生灌输知识。解决物理问题不仅是衡量学生是否掌握物理知识的主......

论述了基于Petri网络理论进行电网故障诊断的方法,描述了故障元件、保护、开关之间内在的动作关系,提出了运用简单的矩阵计算进行......

In this paper a new chemical method has been developed for separating rare-earth minerals, such as rare-earth-carbonates......