How to shield the difference among the distributed heterogeneous database is the primary problem to be solved to implement the mutual visiting among the multiple databases.
如何屏蔽分布在不同站点上的异构数据库之间的差异，是实现多个数据库互访要解决的首要问题。
2
Shield tunneling method has become a primary method in underground excavation with its predominance, earth pressure balanced shield tunneling (EPBS) is the most universal type in our country.
盾构隧道法开挖凭借自身的优势成为城市地下施工的主要手段，其中土压平衡式盾构目前在国内使用较为普遍。
3
Its shielded box should be used the main air gap and prevent the primary current to produce the magnetic field concentrating in the shield shell metal plate.