塑性收缩裂缝和断板的探讨及施工控制

塑性收缩裂缝和断板是水泥混凝土路面滑模施工所要解决的难点 ,这些病害受众多因素的影响 ,找清原因 ,措施得当是解决问题的关键。通过试验研究及泰化高速公路、青威一级公路的实践 ,总结了一系列成功的经验 ,对控制滑模施工出现的塑性收缩裂缝和断板具有很强的可操作性     

影响地方高等级公路建设质量管理的主要因素及其对策

影响地方高等级公路质量管理的主要因素是建设资金短缺，施工队伍素质差，地方行政干预大，管理制度不落实，不按基本建设程序办事等。采取分期建设，实行公开招标落实施工队伍，主要材料由业主购买并控制耗量，重要构件在专业化工厂定制或由专业化工厂在现场制作安装，砌石砂浆集中拌制等措施，可以控制好地方高等级公路建设质量。     

基于CORBA与RMI／EJB的异构分布对象系统的集成

本文系统地分析了分布式计算模型CORBVA，Java RMI的体系结构及组件模型EJB的现状和发展趋势的基础上，对CORBA与RMI／EJB的集成进行研究，并将其应用于大庆站信息系统的开发。     

Flexible long range planning using low cost information

Contemporary transport planning requires a flexible modelling approach which can be used to monitor the implementation of a long term plan checking regularly its short term performance with easily available data; the original model is periodically updated using low cost information and this allows the evaluation of the changes to the plan which may be required. Such an approach requires models suited to regular updating and to the use of data from different sources. Models to update trip matrices from traffic counts have been available for some time; however, the estimation and/or updating of other model stages with low cost data has escaped analytical treatment. The paper discusses this idea and formulates the updating problem for an example involving a joint destination/mode choice model under various assumptions about the nature of the available data. Analytical solutions are proposed as well as some general conclusions.requests for offprints     

Calculation of Transient Stress Field During Laser Transformation Hardening Process

IntroductionHighpowerCOzlaserssdsetransformationhardeningtechniquehasbeensuccessfullyusedinindusnyforWYears.BecausethetemPeratUrefleldislocalizedinmaterialdurllglasertransfonnationhMngProcess,highthermstrCsswillgenerateinmatgrialduringlasertfansformationhardeningProcess.Therisalsohighresidualstressinmaterial,bothintCnsionandcomPression['-'].ComPressresidualstressishelptoincreasethefatigueldrimeofthelasertreatedmaterial,butthetensilestresswillshortenthefatiguelifetmeofthelasertreatedmator…     

搞好新建公路绿化 恢复自然生态平衡

结合哈同公路佳哈段的绿化谈公路绿化美化的作用和方法 ,总结经验并指出了不足 ,可供有关人员参考。     

Challenges and Prospects of Fisheries Co-Management under a Marine Extractive Reserve Framework in Northeastern Brazil

In Brazil, Marine Extractive Reserves—MERs (Reservas Extrativistas Marinhas) represent the most significant government-supported effort to protect the common property resources upon which traditional small-scale fishers depend. From an initial small-scale experience in 1992, MERs have expanded countrywide, now encompassing 30 units (9,700 km²) and nearly 60,000 fishers. Despite such escalating interest in the model, there is little research on the effectiveness of MERs. In this article, we discuss relevant parts of the history and examine the current situation of the fisheries co-management initiative in the Marine Extractive Reserve of Corumbau, which was created in 2000 as the first MER to encompass coral reefs and reef fisheries. We describe the Extractive Reserve co-management arrangement and its main policy and legislative challenges. Finally, we discuss the prospects for the use of MERs as management frameworks for traditional small-scale fisheries in Brazil.     

Analysing the effect of trip satisfaction on satisfaction with the leisure activity at the destination of the trip,in relationship with life satisfaction

Transportation - Previous studies have indicated that positive (or negative) experiences of activity episodes are likely to correlate with positive (or negative) evaluations of a persons’...     

少支点支架在跨线桥整体现浇施工中的关键技术

现浇立交桥的跨线施工中,使用少支点支架进行施工,不仅满足了下跨线的安全运营问题,而且操作简单、快捷,施工质量也可以得到了保证。该文结合苏州工业园区北环路东延工程整体现浇跨越苏嘉杭高速施工过程,介绍了少支点支架在跨线桥整体现浇施工中的关键技术,可供桥梁施工人员参考。     

爆炸消除焊接残余应力的数值模拟

焊接残余应力及其控制技术是重大工程结构物(例如反应堆、潜艇等)建造中关注的核心问题之一。爆炸法消除残余应力是近年来发展起来的高效、低成本的1种新技术,但对其机理的研究仍然相当缺乏。本文利用非线性有限元软件ABAQUS对爆炸消除焊接残余应力技术进行了数值模拟,同时考察了焊缝中夹杂的裂纹缺陷对爆炸载荷的响应。研究对象为70 mm厚的超厚钢板对接焊缝,焊接坡口为X型。本文主要完成了以下2项研究工作。1)将盲孔法测得的焊接残余应力分布预置到模型中,计算了爆炸载荷作用下不同布药方式时焊接残余应力的再分布,并将其与对应的实测结果进行比较。研究结果表明,金属材料的塑性流动是爆炸消除焊接残余应力的根本因素。2)在模型的焊缝区引入面状裂纹来表征焊缝中的凝固裂纹,利用ABAQUS用户自定义子程序开发的基于虚拟裂纹闭合法的三维断裂单元,计算能量释放率对爆炸载荷的响应。研究结果表明,爆炸载荷并不一定会导致裂纹的扩展。因此,本文的研究方法和结果对于爆炸消除焊接残余应力在工程应用领域具有指导意义。