开洞网架结构的稳定性分析

以弹性支座下的开有矩形洞口的双层正放四角锥网架结构为研究对象,利用SAP2000对开洞网架和不开洞网架分别进行了线性屈曲和非线性屈曲分析,获得了开洞网架结构的屈曲荷载、极限荷载及塑性铰发展过程,并分析了不同开洞大小和位置对网架结构整体稳定性的影响。分析结果表明：洞口大小与位置对网架的稳定性影响不可忽略,开洞网架结构较不开洞网架的稳定性承载力显著减小,必须限制洞口的长宽比以减小对稳定性的不利影响;开洞网架与不开洞网架结构屈服机制不同,未开洞网架的屈服一般从中央上弦杆开始而开洞网架结构塑性铰则首先出现在洞口四角处的腹杆上;在洞边增加拉压杆对提高网架结构的稳定性效果并不明显,需采取加大杆件截面尺寸等加强措施以避免洞口处杆件过早屈服。     

基于大学生科学商店的上海科普资源整合与利用机制创新

为推动科普事业发展,在全社会建立跨部门、社会化的科普资源整合与利用机制,以上海、北京等地为代表的城市政府借鉴欧美经验引进创办了大学生科学商店。在实地调研的基础上,对科普资源整合与利用机制、上海大学生科学商店模式进行了综述性研究,从经费投入、社会动员、创新激励、协调管理和评估反馈等五大机制层面探讨了该模式对上海科普资源整合与利用机制的突破与创新。     

滚珠丝杠及丝母预紧力自动测控装置设计

以滚珠丝杠及丝母预紧力装置为对象,在分析和研究以往对滚珠丝杠预紧力测量装置的基础上,设计了一种新的连续可调预紧装置并进行了MATLAB/SIMULINK仿真,仿真显示设计效果良好,为以后滚珠丝杠的装配提供了切实可行的依据。     

一种专门用于金属丝抗拉强度自动检测仪的夹紧机构的设计

介绍了一种能够自动检测金属丝抗拉强度的检测仪,并着重说明了专用夹紧机构的设计。该机构能够很好地解决在试件检测过程中的夹紧问题,从而有效地提高了检测过程的可靠性和工作效率,使设备更加适于生产现场的连续批量检测任务。     

基于ABAQUS的钢管混凝土组合剪力墙弹塑性有限元分析

钢管混凝土组合剪力墙是一种新型剪力墙,能充分发挥不同受力体系和不同材料的抗震优势.采用大型有限元分析软件ABAQUS对该新型剪力墙进行了弹塑性有限元分析,研究了钢管混凝土组合剪力墙在荷载作用下的应力、应变等微观受力状态,揭示了其破坏过程和抗震机理.     

Orientation density and workspace analysis of a parallel stabilized platform testing system

An optimized workspace calculation method is proposed for parallel stabilized platform testing systems.This method refines the searched space progressively in order to approach the boundary of the workspace from both the inside and the outside of it.The orientation density is defined and used as an evaluation index to calculate the orientation workspace.The algorithm of the orientation density is embedded into the computer program of the workspace calculation.Then the workspaces of the testing system are solved.In the solution,the orientation density is regarded as a discrete function of the reachable workspace.As a result,the reachable workspace and the orientation workspace are represented in the same multidimensional graphs.Finally the useful workspace of the testing system is determined based on these results.This case study indicates that the calculation efficiency is enhanced by adopting the optimized method and the practicability of workspace study is improved by proposing the orientation density.     

Properties and mechanism of red mud in preparation of ultra-lightweight sludge-red mud ceramics

New ultra-lightweight sludge-red mud ceramics (ULS-RMC) were prepared by red mud (RM), clay and dried sewage sludge (DSS). The properties and mechanism of RM in the preparation of ULS-RMC were discussed. The chemical components, thermal properties and mineral phases of RM were determined by energy dispersive X-ray (EDX), differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA) and X-ray diffraction (XRD), respectively. Constant dosage of DSS to clay and different amounts of RM were utilized in the preparation of ULS-RMC. Physical properties test (bulk density, grain density, water absorption and expansion ratio), XRD and scanning electron microscopy (SEM) were employed to characterize the ULS-RMC. The results show that RM exhibits high hydroscopic property and good water-retention property, and bloating property and fluxing property of RM are caused by abound of gaseous components and flux, respectively. The two chemical properties are utilized to discuss the mineral phases and microstructures differences between ULSC and ULS-RMC.     

淮安市建设苏北重要中心城市动力机制研究

在深入分析与探索可以促使淮安市中心城市建设持续推进和发展的主要动力因素基础上,运用系统动力学的理论和原理,构建由相关决策变量、增长极、动力变量和城市中心化水平等因素构成的概念模型,从而在理论和逻辑上理清淮安市中心城市建设的动力机制问题,并可作为政府部门决策参考及后续研究基础。     

高校党建工作机制的构建与创新

党建工作机制对于党建工作的健康发展具有基础性和根本性的保障作用.在高校党建工作机制建设中,通过创建"书记亲自抓"的领导机制、多部门协作的联动机制、程序完善的党员培养教育管理机制、特色鲜明的党建工作品牌机制,以及符合"四有"标准的党建工作保障机制,能够使高校党建工作在内外条件发生变化时自动迅速地作出反应,及时调整和优化已定的策略和措施,以促进实现"培养中国特色社会主义事业合格建设者和可靠接班人"的战略目标.