1) three lays and four regions
三层四区
1.
According to the security principles of the state power grid ,the whole dispatching information system networks is divided to “three lays and four regions”, also the paper descr.
按照原国家电力公司制定的有关规定，论文重点介绍了电力系统“三层四区”的概念，即按照调度管理体制，把整个省级电力调度信息系统纵向分为：省级调度中心、地区级调度中心、县级和变电站调度室这三个层面。
2) 3-and 4-stage fault
三、四级断层
1.
Research and exploration practice on screened reservoir-forming of 3-and 4-stage fault in complex fault zone-taking central anticlinal belt of Dongying sag as an example.;
复杂断裂带三、四级断层遮挡成藏研究与勘探实践——以东营凹陷中央背斜带为例
3) Third and Fourth Order Stratigraphic Cycles
三.四级地层层序
5) magnetite
[英]['mægnitait] [美]['mægnə,taɪt]
四氧化三铁锈层
6) three counties and four areas in Hefei
合肥市三县四区
补充资料：三层大，二层小
1.谓家庭中人口众杂，上辈之上还有上辈，下辈下面还有下辈。
说明：补充资料仅用于学习参考，请勿用于其它任何用途。
参考词条