The optimum programme can be used to design four-connecting lever pneumatic roof-window mechanism of all kinds of multi-span plastic greenhouses by changing load and structure parameters.
通过改变载荷参数和结构参数，优化模型可用于其它塑料温室的气动四连杆天窗机构的设计。
2
This paper puts forward a new system of multi-prestressed steel lattice shell structure for large span space roof.
本文对大跨度空间屋盖提出了一种多次预应力钢网壳结构新体系。
3
Underwater placement of bridge's platform and cradle construction method for multi-span continuous box-girder structure constitute the construction feature of Fuyang bridge in Zhejiang province.