加强型聚碳硅氧烷防腐涂层在桥梁水泥混凝土防撞护栏防腐蚀施工中的应用

针对山东惠青黄河公路大桥水泥混凝土防撞护栏的病害,制定了加强型聚碳硅氧烷防腐涂层加固施工总体方案。对防腐涂层选择的RBS高弹性高分子防腐防水涂料、SHJS聚碳硅氧烷防腐涂料及 SHJS高聚物碳钢修补材料的性能及优点进行了介绍,对加强型聚碳硅氧烷防腐涂层的施工技术及质量控制要点进行了阐述和总结。护栏加固维修后,通过8a的观察,发现护栏状态良好,达到了维修方案的预期效果。维修方案通过对防腐基层的特殊处理和对防腐涂层的加厚,使得该防腐涂层质量更可靠。     

Integration of signal timing estimation model and dynamic traffic assignment in feedback loops: system design and case study

This paper presents an integrated framework for effective coupling of a signal timing estimation model and dynamic traffic assignment (DTA) in feedback loops. There are many challenges in effectively integrating signal timing tools with DTA software systems, such as data availability, exchange format, and system coupling. In this research, a tight coupling between a DTA model with various queue‐based simulation models and a quick estimation method Excel‐based signal control tool is achieved and tested. The presented framework design offers an automated solution for providing realistic signal timing parameters and intersection movement capacity allocation, especially for future year scenarios. The framework was used to design an open‐source data hub for multi‐resolution modeling in analysis, modeling and simulation applications, in which a typical regional planning model can be quickly converted to microscopic traffic simulation and signal optimization models. The coupling design and feedback loops are first demonstrated on a simple network, and we examine the theoretically important questions on the number of iterations required for reaching stable solutions in feedback loops. As shown in our experiment, the current coupled application becomes stable after about 30 iterations, when the capacity and signal timing parameters can quickly converge, while DTA's route switching model predominately determines and typically requires more iterations to reach a stable condition. A real‐world work zone case study illustrates how this application can be used to assess impacts of road construction or traffic incident events that disrupt normal traffic operations and cause route switching on multiple analysis levels. Copyright © 2014 John Wiley & Sons, Ltd.     

A stochastic computational model for yellow time determination and its application

This paper proposes a stochastic model to determine the yellow time according to the occurring probability of Type‐I dilemma zone (P_DZ). Unlike the conventional methods generally based on the deterministic traffic flow theory, the proposed model fully accounts for the randomness of input variables such as approaching speed, deceleration rate, perception‐and‐reaction time, and distance to stop‐line at the yellow onset. A theoretical model is firstly established, and a computational program incorporating Monte Carlo Simulation is then developed to facilitate its general solution. These two alternative solution approaches to derive P_DZ and Y are proposed, depending upon whether D/V and (τ + V/2d) follow certain analytical distributions or not. In addition, field data at a typical high‐speed highway intersection are collected to validate the model. Based on the validated model, comprehensive sensitivity analysis is conducted to look into the entire picture of the relationship between P_DZ and the distributions as well as correlations of the input variables. To demonstrate the application of the proposed model, the required yellow times for various conditions are calculated based on the acceptable levels of P_DZ, and representative application tables for typical cases are finally provided. With the aid of the proposed methodology, traffic engineers are capable of designing yellow time in a more sophisticated manner. Copyright © 2014 John Wiley & Sons, Ltd.     

高速公路路侧振动带行车安全性分析

随着高速公路路侧振动带的推广应用,振动带的振动冲击力对车辆运行安全性的影响,已成为目前研究人员比较关注的问题。鉴于此,以桑塔纳3000为代表车型,针对切削式、陶瓷式、热熔式三个类型振动带不同的设计方案、布局形式和车辆运行速度等,对振动带的行驶安全性能,从汽车操纵稳定性和车辆机件强度两个方面进行评价和分析。     

多束同心锚锚固区的劈裂力研究

提出预应力箱梁桥设计中群锚锚固区设计存在的问题,并在此基础上进行大量的参数化分析,对群锚同心锚锚固区的劈裂力进行的探讨分析,并提出相应的简化计算公式,对指导实际工作有一定的意义.     

河门口大桥设计探讨

河门口大桥横跨金沙江,设计为大跨高墩连续刚构.设计时要考虑高地震区抗震影响、水库蓄水影响,同时要考虑高边坡开挖,技术难度较大.重点介绍大桥的工程特点、总体布置及科学研究等.     

利用UG软件确定仪表板头部碰撞区域的方法

为缩短整车开发周期,降低设计验证风险,文章详细描述了利用UG软件确定仪表板头部碰撞区的方法。将做出的结果与通过实际试验得出的结果进行了比较,2个结果完全一致。表明该方法是正确的,可以用该方法在汽车仪表板数据设计过程中提前进行法规项的校核。     

公路施工区交通安全管理现状分析

通过文献检索和现场走访调研,对比了我国与发达国家在施工区标准规范和现场交通安全管理2个方面的情况,初步了解了我国公路施工区交通安全管理的现状,对交通安全管理方面存在的问题和诸多不足进行了分析,为施工区交通安全管理的提高和改善指明了方向。     

预应力混凝土箱梁锚下局部应力分析

在大吨位预应力束的作用下,锚下混凝土受力特征复杂,锚固区的安全性和抗裂性是结构设计的关键部分。运用Ansys对腹板锚固区的局部应力特征进行研究,并对张拉腹板束出现的斜裂缝进行原因分析。     

脑的神经再生

侧脑室室管膜下区和齿状回的颗粒下区的神经祖细胞通过增殖和分化产生新生细胞的神经再生过程终生存在于哺乳动物脑内.本文综述了神经祖细胞增殖、迁移、分化并功能性整合的调节机制,并对病理条件下的神经再生以及脑内神经再生研究目前存在的问题和局限性作了进一步的讨论和分析,希望对神经系统疾病的替代治疗研究具有一定的启示作用.