Influence of Track Parameters on Welded Turnout Group

Introduction Welded turnout is a key part for continuouswelded rails (CWRs). Longitudinal force and dis-placement of rails should be considered in the designof welded turnout. When the distance between thewelded turnouts at places like railway stations is…     

单元板式轨道脱空伤损识别的柔度曲率特征值法

为了实现对CRTS Ⅲ板式无砟轨道结构中轨道板板底脱空伤损的识别和定位,首先通过轨道结构模型的模态分析,获取其结构的柔度矩阵,结合高斯曲率和降噪数据处理构建柔度曲率特征值矩阵,利用非伤损区域内反映不规则突起对伤损定位影响的准确性指标和反映识别伤损范围的有效性指标得到合理的测点密度,最后建立多种伤损工况,研究该指标识别的应用范围. 研究结果表明:已脱空轨道板的柔度曲率特征值在伤损区域内存在明显突起,且峰值位置与伤损区域中心吻合,可在无基准参数下有效识别CRTS Ⅰ及CRTS Ⅲ型两种材料性能不同的单元板式轨道板底的隐蔽伤损;针对板底大于0.4 m × 0.4 m的脱空伤损,采用测点密度为0.2 m时有利于降低噪声对伤损定位准确性的影响,提高伤损范围识别的有效性;当轨道板底伤损区域边长大于0.3 m时,可利用柔度曲率特征值进行伤损识别和定位;轨道板柔度曲率最大绝对值随脱空尺寸变大而增加,二者基本呈线性关系,结合柔度曲率特征值的可视化图形可进行伤损面积识别.      

基于iForest+Biscting K-means的驾驶风格辨识方法研究

提出了一种基于iForest+ Biscting K-means模型的客运驾驶员驾驶风格辨识方法.该方法针对在Bisceting K-means模型中,聚类质心严重影响聚类结果问题,采用iForest模型训练聚类中心候选集作为聚类质心集的方法加以改进.通过考察某城际客运线路30位客车职业驾驶员,在直线道路行驶工况下,90余天约400万条客车行驶数据开展模型验证.试验表明:在加速度标准差和超速倾向系数作为聚类指标的情况下,客运驾驶员驾驶风格聚类为谨慎型、普通型和激进型3类,其中谨慎型11人,普通型19人,激进型0人.     

弯曲河道水流泥沙运动研究进展

弯曲河道的水沙运动一直是河流研究者十分关注的课题之一,关系到河道演变与治理.重点概述了单一弯道与连续弯道水沙运动国内外研究进展,梳理了弯曲河道的水面比降、纵横向流速分布、悬移质泥沙及推移质泥沙的运动特性.分析结果表明:以往研究大多是基于相对平衡的水沙条件与尺度相对较小的自然河流情况下取得的成果,针对水沙过程发生较大变化尤其是来沙大幅度减少的大尺度河流的弯曲河道水沙运动规律研究较少,限制了对减沙条件下大尺度弯曲河道演变规律的深入认识.因此,需要在前人研究基础上开展变化环境下弯曲河道水沙运动特性的研究,为进一步深入研究弯道演变规律与治理提供基础.     

Sasobit温拌排水沥青混合料老化性能

为了分析Sasobit温拌排水沥青混合料老化后性能,以热拌OGFC-13沥青混合料、温拌OGFC-13沥青混合料、掺加5%Na Cl的温拌OGFC-13沥青混合料为研究对象,分别在未老化、短期老化、长期老化的条件下,采用室内实验对沥青混合料路用性能进行对比研究.实验结果表明:老化后的混合料高温稳定性、水稳定性、低温抗裂性较未老化时均降低,长期老化的影响最显著,其中对低温抗裂性能影响最大;长期老化后,Na Cl掺量为5%的沥青混合料低温抗裂性较未掺加Na Cl时大幅度下降,说明5%掺量的Na Cl对长期老化后沥青混合料的低温指标有负面影响.     

基于谱分析的路段行程时间多步预测方法

路段多步行程时间预测数据是动态交通诱导系统的重要参数,但已有研究成果,大多集中于一步预测,且存在适应性不强、计算量大、基础数据需求多等不足.应用谱分析及Karhunen-Loeve（K-L）变换对历史及当前检测行程时间序列进行分解与重构,重构时以历史序列与当前检测序列的欧式距离作为相似性度量指标,优化重构时的特征向量系数,使与当前检测序列相似度高的历史序列信息在重构中占据主要地位,通过重构,实现对后续若干时段的行程时间的预测,实测数据检验显示该方法可实现多步预测,预测精度良好,较以往方法有所提高,且历史数据需求量小,计算量小.     

Critical Conditions for Left-Turn Lane’s Stop Line Backwards Setting Under Exclusive Left-Turn Phase

Aiming at the problem that the vehicles always turn left in advance which causes heavy conflicts in the intersection and effected traffic efficiency,the solution of the left-turn lane’s stop line backwards setting was proposed,and the critical conditions on the stop line’s setting were studied.Firstly,we studied the characteristics of trajectories distribution in the release process of turning left in advance vehicles.Based on that,we proposed to move the stop line backwards to solve the problem of turning left in advance.Considering the intersection’s geometric features and the vehicle operation features,the geometric critical condition was given for setting the position of left-turn lane’s stop line.And then the model of left-turn vehicles’queuing length was established based on queuing theory and traffic wave theory.By using queuing length model,the flow restrictions of stop line backwards could be found.Assuming left-turn vehicles’arrival rate is stable in a certain period of time,the minimum green time and the maximum red time of left-turn phase were given after the stop line was set up.According to the changes of the vehicles’turning paths,the shortest yellow setting recommendation was given.Finally,the application of the critical limits used in stop line backwards setting was demonstrated.The research result could provide a theoretical basis for traffic signs and markings’setting and perfect the relevant laws and regulations.     

锂对慢性铝暴露大鼠脑内CDK5和PP2A表达的影响

目的 研究锂对慢性铝暴露大鼠脑内周期蛋白依赖性激酶5(CDK5)和蛋白磷酸酯酶2A(PP2A)表达的影响,进一步探讨锂抑制tau蛋白磷酸化的作用机制.方法 慢性铝暴露大鼠12只,随机分为锂治疗组和非治疗组.锂治疗组给予氯化锂[200mg/(kg·d)]溶液连续灌胃6周;非治疗组以等量生理盐水灌胃.另取6只同月龄非铝暴露大鼠为正常对照组.Morris水迷宫测试3组大鼠学习记忆功能;Western blotting检测大鼠大脑皮层及海马磷酸化tau蛋白、CDK5、PP2A的表达.结果 慢性铝暴露非治疗组大鼠脑内磷酸化tau蛋白含量、CDK5表达明显高于正常对照组大鼠(P<0.05),且慢性铝暴露非治疗组大鼠脑内磷酸化tau蛋白含量与CDK5表达呈正相关(r=0.702,P=0.036).锂治疗组大鼠脑内磷酸化tau蛋白含量、CDK5表达明显低于非治疗组(P<0.05),且锂治疗组大鼠脑内CDK5表达与磷酸化tau蛋白含量呈正相关(r=0.871,P=0.024),而正常组、锂治疗组和非治疗组大鼠皮层及海马PP2A含量无明显差异(P>0.05).结论 抑制脑内CDK5表达可能是锂降低tau蛋白过度磷酸化,减少大鼠脑内神经原纤维缠结的又一途径.     

钢轨电位分布模型及仿真

随着电力机车牵引电流不断增大,钢轨电位过高成为突出问题.本文通过建立直供方式下钢轨电位的分布参数模型,并用MATLAB进行仿真,得出了钢轨上电位和电流的分布情况.分析了主要参数对钢轨电位分布的影响;考虑机车本身的影响,引入了机车系数来修正钢轨电位峰值.最后给出了在通常情况下钢轨电位计算值和实际值的比较,验证了模型的正确性.     

Intelligent Vehicle's Path Tracking Based on Fuzzy Control

Autopilot vehicle is an important part of intelligent transportation systems. The objective is to develop the driver assistance systems on highway and urban road, to help or even to replace the driver, which may reduce traffic accidents and improve the efficiency of traffic system. A method based on machine vision and fuzzy control is proposed to realize intelligent vehicles' autopilot. It uses the CMOS sensor as its path recognition device to draw its lane centerline through image analysis. Taking the feedback speed as the additional input, the study forms the closed-loop control and establishes one graduation fuzzy controller which controls vehicle direction with two fuzzy controller combinations and replaces traditional PID control vehicle speed by fuzzy control. Compare with the conventional PID algorithm and the fuzzy control algorithm, the improved fuzzy control algorithm ensures a high speed and steady running of intelligent vehicle with smaller over modulation in corner.