门座起重机刚柔耦合动力学仿真研究

基于虚拟样机技术,针对门座起重机刚柔耦合系统及钢丝绳柔性,利用UG,ADAMS与AN-SYS联合建模,进行起升、变幅和回转工况过程的动态仿真,为门座起重机的设计和分析提供了一种新方法.结果表明,该仿真模型能准确模拟门座起重机各作业工况运动和动态响应.     

Experimental study on mechanical behavior of box-brace to box-column foot joints

This paper presents results of three tests carried out to study the mechanical behavior of foot joints used in the tower boiler steel frame. Each foot joint consists of a box column and a box brace. These three specimens have different connection types or different details of stiffeners. The tests are carried out by using the large multi-function structural experiment system WAW-1000J. The load-displacement curves and the strain distribution are measured during the tests. The mechanical behavior of foot joints under adverse load cases is analyzed. The safety of these three specimens under design load is assessed. The strength and deformation of different joints are compared. The results indicate that connection types or details of inner stiffeners have effects on strength and failure mode and that the specimen with end-plate connection can optimize the strain distribution along the height of brace web and can change the force transfer mechanism between column and brace. In addition, a finite element model of the specimen is conducted and numerical results generally agree well with the test results. The work in this paper provides a base for further analysis on the performance of joint used in the tower boiler steel frames.     

Surface hardness evaluation of components made by color stereolithography

Surface hardness value is a commonly used indicator for describing the mechanical property of stereolithography parts. In order to investigate colorants how to influence the surface hardness of colorful resin component, a procedure is proposed to fabricate testing specimens based on color stereolithography technology in this study. Liquid photosensitive resin LPR2001 is mixed with two colorants （phthalocyanine blue and eosin powder） respectively before curing. The phthalocyanine blue powder is insoluble and only dispersive in the solid- liquid mixture which results in deposits. Therefore, surface modification is conducted to the phthalocyanine blue powder for improving wettability. By contrast, the eosin powder is dissoluble and does not cause any deposits in the liquid resin. Specimens are produced by laser curing colored resin and tested by MTSR Nano Indenter XP system. The change of hardness values is illustrated at certain mass percentages of colorant. Comparisons and discussions are carried out to explain the colorants＇ effect. It is concluded that incorporating colorant to liquid resin results in decreasing the surface hardness of components. But sensibilization effect of the colorants also influences the curing process. Surface modification to the phthalocyanine blue powder is a feasible method to increase the hardness value of color stereolithography components. Dissolvable eosin has an approximate linear effect on surface hardness.     

The effect of bile reflux on the intragastric pH

Oblective To observe the effect of bile reflux on the intragastric pH. Methods We used ambulatory intragastric pH monitoring along with simultaneous Bilitec 2000 to measure the pH and absorbance of the mixed gastric juice diluted with bile with increasing bilirubin concentration in vitro and the yellow and clear gastric juice aspirated under endoscopy. In vivo,we studied 20 functional dispepsia patients for 24 h with simultaneous intragastric pH and bilirubin monitoring. Results In vitro dilutions,the absorbance value reached to 0. 900 while the concentration was only 20% ,but when the pH of the solution was more than 4,it′s concentration was already up to 60％. The mean absorbance of the yellow gastric juice(0. 348± 0. 131) was significantly higher than that of the clear juice (0. 008 ± 0. 003)(P＜0.05). The pH of 80％ yellow gastric juice was less than 4, the percentage was not significantly different from the clear samples (81％) (P＞0. 05). The pH showed no correlation with the absorbance in the yellow and clear groungs. Eight of the 12 patients with the spontaneous nocturnal episcodes of alkalinization had simultaneous increase of absorbance,4 of the 8 subjects with no aikalinization had increase of absorbance. Gonclusion In some concentration,bile reflux affect little on the intragastric pH.     

一种无人驾驶轮式越野车导航定位与自引导方法

介绍了一种越野环境下无人驾驶轮式越野车导航定位与自引导方法,说明了地图创建、目标引导和路径规划与跟踪的控制策略.通过实车试验验证了文中提出方法的可行性和可靠性.     

卵石持力层桩端后压浆效果检测分析

该文介绍了杭州德胜快速路桩端持力层为卵石层的两根桩端后压浆钻孔灌注桩所进行的自平衡测试。结果表明后压浆对钻孔灌注桩的承载力提高具有显著效果。通过钻孔取芯试验,发现压浆后20d测试时,水泥浆与土形成的水泥土固结体几何形状不规则,还未达到稳定,因此随着水泥土强度逐步提高,桩身承载力会进一步增大。通过对比分析,论证了后压浆技术会带来很好的经济效益。     

电控系统下线管理与故障诊断功能开发

在Infineon XC167平台的电控单元上开发了基于CAN总线ISO15765协议的电控单元下线功能,以及SAE J1939协议的车辆运行数据共享和故障诊断功能.软件具有良好的模块化结构和可移植性,可以应用在不同的硬件平台上.     

Eliminator防水体系及浇注式沥青混凝土在无锡S342钢箱梁桥面施工中的应用

该文介绍了Eliminator防水体系及浇注式沥青混凝土应用于无锡S342主线西互通钢箱梁桥面铺装底层的情况,详细阐述了铺装方案及施工过程,根据已完工程的施工经验,并结合无锡S342主线西互通钢箱梁桥的实际情况,总结了施工工艺。     

干湿循环-硫酸盐侵蚀下混凝土损伤机理的分析

结合扩散-反应方程,重点分析了干湿循环-硫酸盐侵蚀作用混凝土的侵蚀机理.研究认为干湿循环改变了硫酸盐介质在混凝土中的迁移方式和侵蚀过程,加剧了混凝土性能的劣化.通过对研究成果的总结与分析,指出了几种主要因素,如硫酸盐种类及浓度、矿物掺合料、混凝土强度等级等,对侵蚀后混凝土性能的影响规律.     

城市路内停车管理战略及实践

为有效缓解城市停车问题,从公安交通管理角度研究路内停车管理战略。首先探讨路内违章停车对道路交通的影响,并分析问题的根源。提出引导式路内停车管理战略架构,在分析城市路内停车功能定位的基础上,阐述停车管理战略意义和目标。从确定严管区域、合理设置路内停车位、完善停车安全管理设施、强化执法手段和加大处罚力度五个方面提出路内停车管理措施;从加强宣传、增加有效停车位供给、调整城市交通结构和建立停车位电子档案库四个方面提出引导式停车管理配套措施,并探讨相应的战略保障机制。最后,通过杭州市和长沙市实例分析了停车管理战略的应用效果。