The characteristics of welding currents in a rotating arc lead tandem GMAW process and the weld-seam tracking

Tandem gas metal arc welding (T-GMAW) process shows a high deposition rate that up to three times of the single electrode GMAW,so the welding speed could be significantly increased in this process.However,the majority of this process applications are based on the pre-programmed robotic welding,which does not allow them to track the seam real-time during welding.Rotating arc sensor,sensing the seam position by detecting the changing of welding currents,has been widely adopted in the automatic robot welding process.It is proposed in this paper to integrate the rotating arc sensor with a trailing torch to develop a new approach of rotating arc lead tandem gas metal arc welding (RLT-GMAW) process.The characteristics of the welding currents in the proposed new welding process were firstly studied,and then a self-turning fuzzy control seam tracking strategy was developed for the mobile robot automatic welding.The experimental results showed that the proposed RLT-GMAW process had an excellent seam tracking performance and high welding deposition rate.Even if there were some electromagnetic interactions between the two arcs,the deviation of the welding seam could also be reflected by the fluctuation of the welding currents on the leading arc once the correct welding parameters were selected.Based on the detected deviation,the welding tracking experiments showed that the proposed self-turning fuzzy controller had a good performance for the RLT-GMA W process seam tracking.     

变电站带电水冲洗机器人的运动学建模与仿真分析

带电水冲洗是变电站绝缘子串防污闪的主要措施,应用带电水冲洗机器人,可以解决人工水冲洗存在的问题。介绍了带电水冲洗机器人的构型,对其移动底盘、机械臂和整机进行运动学建模,并进行仿真分析。所做研究为带电水冲洗机器人的优化设计与应用提供了参考。     

灌区信息化系统集成方案研究与实现

针对灌区信息化过程中因投资的阶段性而导致的软件系统分割和异构给集成带来的困难,研究了基于门户的异构软件系统的集成模型、结构和实现方法。这个方法充分利用Java所固有的平台无关性,通过Web服务来实现基于门户的集成。门户采用网站方式,通过模型视图控制（Model View Control,MVC）模式访问外网的订阅数据库,实现对各种页面的浏览。业务系统通过Web服务建立与异构子系统的交互,实现访问控制和数据交换。而单点登录则实现了对用户权限的一次性认证,因此,简化了操作,也保证了系统执行过程管理的统一性。     

白兰花园长短桩复合地基设计

介绍长短桩复合地基在白兰花园工程设计中的应用的设计思路和计算方法,可为同类工程设计提供参考。     

坚持创新发展 完善约束机制 加强认可监管

2007年的认可工作在各方面都取得了新的发展。认可运行体系进一步完善，认可约束作用进一步增强。认可工作内容进一步拓宽。认可制度影响力进一步扩大，基础建设和自身能力得到进一步加强。     

女儿墙、框架填充墙的裂缝控制实践

本文采用设构造柱方法控制了砌体女儿墙温度裂缝的发生，并给出了这种控制方法的计算万法。对框架填充墙外顶面与梁底界面间的裂缝进行了估算，采用挂丝网等施工方法，控制了外墙饰面砖开裂的质量通病，可供类似工程参考。     

Rheology elasticity determined by deformation of stretchable molecular trains

The average stretching direction,local rotation angular,and stretching ratio parameters of molecular trains were used to express the rheology deformation.Based on this micro geometrical deformation,the macro deformation of medium was expressed.Then,using intrinsic elasticity concept,the stress-strain relation was obtained.In this theoretic formulation,the response functions of extension ratio and rotation angular were used to express the rheology feature of medium.For medium composed by incompressible molecular trains,the local rotation angular divides rheology deformation into three kinds:viscoelastic deformation or elasticity enhancement,viscoplastic deformation or elasticity degenerate and constant elasticity range.These results explain the experimental features of rheology deformation well.     

正交介质弹性本构关系及角散的研究

本文首先讨论了双层EDA裂隙介质的各向异性弹性本构关系，并导出了基于Postma方法的正交EDA介质的等效弹性常数求解公式和角散公式；然后简要介绍了正演伪谱法算法；最后分别利用角散公式和伪谱法对正交介质的波速与走时进行了数值模拟计算，获得了一致的结果，即正交介质的S波分裂现象比其他介质类型明显。     

汽油机与加热器联合运行降低冷起动阶段排放水平的试验研究

为满足欧-Ⅲ排放法规的要求,提出了通过利用汽车加热器在冷起动前提升汽油机温度的方案,重点解决了-7℃环境温度下的冷起动排放问题.在欧-Ⅲ低温冷起动模拟试验台架上进行了汽油机与加热器联合运行以后冷起动阶段排放水平的初步测试.试验结果表明:该方案能够有效降低汽油机冷起动阶段的THC、CO、NOx有害气体排放量.     

3，3’-二乙基-4，4’-二苯甲烷型多马来酰亚胺／聚苯醚树脂的固化反应研究

热固性聚苯醚(PPO)已成为高性能印制电路板用树脂(PCB)发展的主流。本课题组的前期研究表明,3,3,-二乙基-4,4,-二苯甲烷型多马来酰亚胺(PEDM)/烯丙基化PPO是一种新型高性能PCB用树脂。文章采用红外光谱和裂解气相色谱,对PEDM的含量为PPO 10%的PEDM/烯丙基化PPO树脂的固化反应进行研究,结果表明,PEDM分子的不饱和双键与PPO的烯丙基和羟基在加热过程中发生了反应。