独立存在体
1.Under the earthquake, towers which vibrate severally if there is no connective structures occur interacting because of the connection. Their responses are more complex than that of a single tower or twin towers without the connective structure. Vibration coupling and torsion increasing will occur.
2.Onepart of silver is lied in galena, chalcopyrite and pyrite as independent minerals, such asnature silver, pyrargyrite, argentite, tetrahedrite, polybasite and silver-bearingtetrahedrite, another part of silver is lied in sulphide as isomorphism, and galena is avery important mineral inclusing silver which reaches 1000～2000(×10-6).
