使用30°楔形防松螺纹安装扭矩的建议

为明确30°楔形防松螺纹在同样的施加扭矩下所获得的轴力。试验了30°楔形防松螺纹和普通螺纹经振动防松试验轴力的衰减情况和同扭矩下扭矩系数及轴力的比对试验。从而获得在施加相同扭矩下,30°楔形防松螺纹所获得的轴力比普通螺纹所获得的轴力低。     

老化公路SBS改性沥青多次再生的流变性能与耐久性研究

提取随岳高速公路废旧SBS改性沥青作为研究对象,采用0.8粉胶比并叠加9%再生剂配置沥青胶浆,利用旋转薄膜烘烤和PAV叠加仪对SBS改性沥青进行多次老化和再生。然后通过车辙因子G、劲度模数S和蠕变因子m对多次再生SBS改性沥青的流变性能和低温抗疲劳性能进行了回归分析和总结。研究发现:随着老化与再生次数增多,再生剂对于SBS改性沥青的再生效果逐渐变差,粘弹性逐渐降低;高温下多次再生沥青胶浆的车辙因子随着再生次数的增加呈现逐渐增强的趋势,并且三次老化>二次老化>一次老化>三次再生>二次再生>一次再生>原样;中温重复加载试验中二次老化与三次再生的衰减程度差别一般为2%~3%;低温下沥青胶浆的劲度模数与再生次数呈反向关系,多次再生后沥青胶浆的m值不具有明细的规律性,多次再生样品拥有更好抗低温性能,但是m值曲线与原装沥青胶浆的离散型偏大。     

解析铁道行业标准《铁道客车及动车组集便装置》

从规范性引用文件,产品使用环境条件,产品防护等级,产品可靠性、可维护性及安全性规定,以及污物箱液位开关等方面,解析TB/T 3338—2013《铁道客车及动车组集便装置》,对标准的实施提出具体建议。     

公路隧道交通量的预测及分析

公路隧道交通量的预测对隧道通风系统的节能以及降低隧道运营成本有很重要的意义。分别利用多元统计分析法和BP神经网络两种方法对公路隧道交通量进行了预测,并对两类预测数据进行分析比较,得出了多元统计分析法适用于车流量少而且稳定的公路隧道的预测,而BP神经网络法则适用于车流量大而且不稳定的公路隧道的预测的结论。     

Lane-harmonised passenger car equivalents for heterogeneous expressway traffic

In order to account for variations in traffic composition during traffic analysis, passenger car equivalent (PCE) factors are used to convert flow rates of various vehicle classes into flow rates in terms of passenger car units (PCUs). Earlier studies have developed various methods to estimate PCE values but only a few of them are based on uninterrupted traffic flow, particularly for flow regimes with heterogeneous traffic where differential (lower) speed limits are imposed on commercial vehicles. This paper proposes a lane-harmonisation approach, which leverages on the high variation in traffic composition across the lanes, to estimate PCE factors for urban expressways. Multiple linear regression is used and the PCE factors obtained for motorcycles, light goods vehicles, and heavy goods vehicles are 0.65, 1.53, and 2.75, respectively. The estimated capacity flow rate after the application of the obtained PCE factors is around 2200 PCUs per hour per lane.     

沥青路面使用性能评价中行驶质量与路面损坏的关系探讨

现有的沥青路面使用性能评价体系,通过对路面的损坏状况指数、行驶质量指数、车辙深度指数、抗滑性能指数及结构强度指数的线性加权,获得路面使用性能指数。其中,影响路面行驶质量指数的主要因素是路面平整度,而它受到如裂缝、坑槽、修补等路面损坏的影响。因此,路面行驶质量指数与路面损坏状况指数存在着某种重叠关系,但这种关系并不明确,...     

低温环境钢筋剥肋滚轧直螺纹套筒连接可靠性研究

通过不同温度条件下接头及钢筋母材的力学试验,得出结论：钢筋直螺纹套筒连接的伸长率与钢筋母材的伸长率在常温至-50℃呈现有规律的变化,钢筋直螺纹套筒连接在常温至-50℃的力学性能指标满足规范要求,论证了在北方严寒环境中使用钢筋剥肋直螺纹套筒接头的可靠性。     

Bus arrival time prediction at bus stop with multiple routes

Provision of accurate bus arrival information is vital to passengers for reducing their anxieties and waiting times at bus stop. This paper proposes models to predict bus arrival times at the same bus stop but with different routes. In the proposed models, bus running times of multiple routes are used for predicting the bus arrival time of each of these bus routes. Several methods, which include support vector machine (SVM), artificial neural network (ANN), k nearest neighbours algorithm (k-NN) and linear regression (LR), are adopted for the bus arrival time prediction. Observation surveys are conducted to collect bus running and arrival time data for validation of the proposed models. The results show that the proposed models are more accurate than the models based on the bus running times of single route. Moreover, it is found that the SVM model performs the best among the four proposed models for predicting the bus arrival times at bus stop with multiple routes.     

基于MFC的多线程编程技术在插销试验机微机控制系统中的应用

介绍了在Windows95下基于MFC的多线程编程技术及其在插销试验机微机实时控制系统中的应用,着重阐述了在插销试验机微机控制系统中多线程的同步问题,并给出了编程实例。     

基于灰色聚类分析的城市交通路网综合评价方法研究

针对城市交通路网的多指标综合评价中存在的主观性等问题,依据灰色聚类分析原理,提供了一种计算各指标权重的方法,使得指标之间的权重在评价过程中自动产生,不需要经过人为判断,减少了评价过程中的主观因素。在此基础上,结合杭州市萧山区城市路网进行综合评价,并根据评价过程与结果,提出路网改善建议。