电阻箱的故障分析与调修

电阻箱是广泛用于工矿企业、科研单位的重要精密电测量计量器具。本文对电阻箱的残余电阻大及接触电阻变差大、电阻箱示值超差、电阻箱回路不通或某几个电阻线圈不通三个方面常见的电阻箱故障进行了分析,并提出了调修和正确使用方法。     

Playing on the Field of Social and Technical Innovation: The Impact of the Sale of Lawn Tennis Sets in the Netherlands, 1874–1887

In 1874, after tennis had been played indoors for centuries, British officer Walter Wingfield introduced an open-air version of the game, which he called sphairistike or lawn tennis. He developed a lawn-tennis box that was easy to carry and that contained all the necessary equipment for playing. Wingfield's concept was innovative, not only technologically in both game and design, but also socially. He made it clear, for instance, that lawn tennis was also intended for ladies and he fabricated lighter rackets for women. Little is known, however, about the introduction of lawn tennis in the Netherlands. Our study reveals that the strong sales and marketing concept of Wingfield – and his competitors – also facilitated a quick diffusion of the game in the Netherlands. The first places where lawn tennis was played were estates owned by nobility, seaside resorts such as Domburg and Noordwijk, attracting well-to-do ‘Brits’ for recreational purposes, and – interestingly – also farms. Soon, the first ‘one box clubs’ arose as precursors of the formally established clubs. For most upper-class players, tennis was a leisure-time activity, yet the organization of the first national tennis tournament in 1887 shows that some already had lucrative business models in mind.     

曲线预应力混凝土箱梁桥施工过程研究

文章对一座2×25m的曲线预应力箱形梁桥进行了施工过程的试验研究,并采用三维实体有限元法进行了理论分析。试验结果表明,该曲线预应力箱梁桥设计合理,施工质量可靠。试验与理论分析结果相近,表明该试验方案设计合理,结果可靠,对桥梁建设提供了有效的依据,对实际工程具有一定的指导意义。     

资源受限环境下IPTV益智程序开发

由于受到网络机顶盒性能、内存等资源的限制,使得面向网络机顶盒开发在家即可享受的IPTV服务程序与其他普通程序开发有所不同．本文以一款“快乐娃娃”IPTV益智程序开发为例,从软件开发需求分析、开发环境搭建和程序代码实现等方面,阐述了使用小图片和少代码行数的小功能程序开发的实现方法．“快乐娃娃”程序的开发可为相关程序开发人员提供技术参考．     

考虑畸变效应的梁单元刚度矩阵应用

基于势能驻值原理和广义坐标法原理推导出考虑截面畸变效应的梁单元刚度矩阵.根据此梁单元刚度矩阵,编制了计算薄壁钢箱梁结构的有限元程序,且此程序可以考虑截面畸变效应和扭转效应.运用自编程序,分析横隔板间距对薄壁钢箱梁受力性能的影响.通过数值计算,得出布置横隔板对畸变正应力的影响最大,对弯曲正应力的影响很小.畸变荷载作用下,只有当横隔板布置间距小到一定数值时,薄壁箱梁的畸变正应力才会减小.最后,引入畸变翘曲影响系数γ,简化了薄壁箱形梁纵向正应力的计算方法.当横隔板布置间距L与薄壁箱梁横截面最大尺寸H的比值小于2时,畸变翘曲影响系数γ趋于1,表明薄壁箱形梁的畸变正应力趋于零,可以忽略畸变效应的影响.     

某大桥主桥连续箱梁施工技术

结合工程实例,对菱形挂篮的设计与施工、连续箱梁0#段、悬臂梁段与合龙段施工以及悬臂施工中线形控制等方面进行了介绍,可供同类工程参考。     

框计算模式对图书馆机构的影响分析

介绍框计算的概念、构想和实践,认为框计算的理念构想和技术方向与图书馆的追求相契合,框计算模式为图书馆领域提供了全方位的思路借鉴,也可能加剧图书馆机构发展空间和发展质量的危机感。基于框计算模式提出了"数字化服务图书馆"概念,认为将它作为图书馆的高级发展阶段,比数字图书馆定位更适合图书馆机构。     

What's in Your Box? Promoting Self-Reflection and Analysis of External Influences on Gender Expression and Sexual Orientation Attitudes

This lesson plan is designed to stimulate awareness and reflection on personal attitudes toward gender expression and sexual orientation. Participants are guided to identify and analyze how external influences from various socialization agents shape gender and sexual orientation norms and, consequently, personal attitudes about gender expression and sexual orientation. This lesson introduces a box as a metaphor for a human being, with the intention of enlightening participants that humans are dynamic beings with unique characteristics that do not necessarily fit in neat boxes. This lesson plan describes how to achieve these goals in college classrooms and with other adult learners.     

Mastercam的异形箱体数控加工坐标系的设置

介绍在Mastercam中数控加工异形箱体工件时,工件坐标系的设置过程。以此实例详细介绍工件三维实体模型导入Mastercam后,如何将其坐标系方向与Mastercam数控加工坐标系方向转换成一致,再进行工件坐标系设置的方法。     

铁路客运专线箱梁梁体混凝土开裂原因分析与控制

统计目前铁路客运专线箱梁梁体混凝土开裂的现状,分析开裂的主要原因,介绍箱梁梁体混凝土开裂的预防理念和具体措施。