近年来,在"大众创业、万众创新"背景下,高校大学生创新创业教育备受瞩目.朋辈作为一种非正式群体,在高校创新创业教育中的优势和作用逐渐引起重视.综合相关理论、调查研究和案例分析,以朋辈互助和大学生创新创业教育为研究对象,系统梳理了朋辈互助在大学生创新创业教育中的作用和模式,为大学生创新创业教育提供新方法、新思路.

Dahe Shipyard is one of the historical industrial buildings in Hangzhou.The reconstruction includes the protection of historic buildings and reinforcement of internal functions.Existing foundations,brick columns,bearing walls were reinforced;roof truss was recovered;the internal new mezzanine was structured by steel frame;new foundation was erected by single pile-cap-foundation.Those reconstruction measures mix together the characteristics of functional renovation and protection of historical building prefect well.

The span of a purlin in steel roof system usually being designed as the large one,is easily to buckle under the combined action of bending moment and axial force.The stability is guaranteed through two aspects:one is that the purlins connect with roof panel through self-tapping screws,so the roof cladding exerts uniformly distributed flexible constraints on purlins.On the other hand,the anti-sag rods are set at the web of purlin in order to maintain the stability of the roof system,which is equivalent to adding centralized spring at the midspan of the purlin.It was established an isolation model for purlin in roof systems,and analysed the improvement degree of buckling load.It was also verified that the anti-sag rods play apractical role in improving stability of purlin.However,when the constraints of anti-sag rods reach a certain level,a further increase in the constraints of anti-sag rods has no effect on improving of critical loads,so that there is a threshold stiffness.The conclusion can provide a theoretical basis for the design of anti-sag rods and purlin.