This pattern is used to forbid cyclic dependencies between model elements (for example, there is no link from one object to itself).
该模式用于禁止模型元素之间的循环依赖（举例来说，不存在从对象到其本身的连接）。
2
The unsaturated link occurs in a cyclic system.
在环体系中存在不饱和键。
3
The structure of physical layer, link layer and application layer was applied in field-bus of network control, data was gained through cyclic query of principal and subordinate PC in link layer.