Series 709 features a modular design concept which facilitates complete maintenance and assembly by retaining the spring load.
系列709采用模块设计概念，弹簧负载的保持有助于全过程的维护和组装。
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And the effects of the retaining wall stiffness, strut stiffness, perforce and soil spring stiffness on the internal force and deformation of the retaining structures.
The valve consists of an electromagnetic loop, a valve core, a replacement spring and a shell and the valve core consists of a retaining iron, a movable bar and a sealing pad.