通孔玻璃材料的研制

研究了利用废旧玻璃用松装烧结和模压烧结方法生产通孔材料的可能性，以及原始粉末尺寸、烧结工艺和造孔剂添加量对通孔材料的密度和孔隙度的影响。实验结果表明，用废旧玻璃经松装烧结或模压烧结后可制得通孔材料；松装烧结时，随烧结温度提高，烧结保温时间延长，原始粉末粒度变细，烧结后通孔材料的密度增大，而孔隙度降低；模压烧结时造孔剂的最佳百分含量为５％～５０％，且通孔材料随造孔剂的百分含量增加，密度降低，孔隙度增大。     

杭州城市交通拥挤现状及对策

在分析杭州市交通供需现状的基础上,提出了规划多中心结构和混合功能区,以减少不必要的出行以及合理配置交通源,并对改善中心区交通提出切实可行的对策。     

一种改进的基于密度和网格的高维聚类算法

提出了一种改进的基于密度和网格的高维聚类算法,并对算法有效性进行了验证.该算法通过减少样本点数量的方法达到减少稠密子空间数量.在发现高维稠密子空间时,对样本库进行精简.这些样本点的求得能有效减少求解最小聚类的时间复杂度.     

刚构-连续梁桥船撞桥墩最不利位置及安全性评价

以湘府路湘江大桥(65+5×120+65)m刚构-连续梁桥为工程背景,采用2种方法研究了桥墩在纵横向船舶撞击力作用下的墩身弯矩随船舶撞击高度的变化规律,以确定船撞桥墩的最不利位置。方法一采用简化计算模型进行桥墩弯矩公式推导,方法二采用Midas Civil建立空间有限元仿真全桥模型进行墩身弯矩计算。计算结果表明:有限元仿真全桥模型计算得出的墩身弯矩与简化计算模型推导出的结论是一致的,在船撞力作用下整个桥墩中墩底弯矩最大,且墩底弯矩随着船撞力作用点的升高而增大;简化计算模型中采用了若干简化处理,在进行桥梁船撞安全性评价时宜采用有限元仿真全桥模型计算。本文结果对桥墩设计与船撞安全评价具有一定的指导意义,并在此基础上对此刚构—连续梁桥船撞桥墩安全性进行了评价。     

沥青混合料最大理论密度的计算

通过对矿质集料的物理状态及其在混合料中存在方式进行分析,探讨了沥青混合料最大理论密度计算中矿料密度的引用及其影响.     

基于自适应遗传算法的路堤边坡稳定性分析方法

基于圆弧滑动面假定,提出了一种用自适应遗传算法搜索最危险滑动面及其对应的最小安全系数的新方法。该方法是一种改进的遗传算法,采用自适应求取适值、动态调整交叉率和变异率、自适应区间收缩。自适应遗传算法有效克服了传统方法易陷入局部极小的缺陷,提高了算法的搜索效率、精度和稳定性。     

沥青路面破损程度分级与破损换算系数取值的探讨

本文分析现行规范中对沥青路面破损程度、密度分级以及破损换算系数取值中存在问题,通过分析沥青路面破损程度与路面使用状况关系,结合沥青路面养护措施,提出沥青路面裂缝破损密度分级的方法,并对车辙破损严重程度分级标准、裂缝和车辙破损换算系数的修正值提出建议。     

The identification and empirical characterization of vehicular (Lagrangian) fundamental diagrams in multilane traffic flow

Traditional macroscopic traffic flow modeling framework adopts the spatial–temporal coordinate system to analyze traffic flow dynamics. With such modeling and analysis paradigm, complications arise for traffic flow data collected from mobile sensors such as probe vehicles equipped with mobile phones, Bluetooth, and Global Positioning System devices. The vehicle‐based measurement technologies call for new modeling thoughts that address the unique features of moving measurements and explore their full potential. In this paper, we look into the concept of vehicular fundamental diagram (VFD) and discuss its engineering implications. VFD corresponds to a conventional fundamental diagram (FD) in the kinematic wave (KW) theory that adopts space–time coordinates. Similar to the regular FD in the KW theory, VFD encapsulates all traffic flow dynamics. In this paper, to demonstrate the full potential of VFD in interpreting multilane traffic flow dynamics, we generalize the classical Edie's formula and propose a direct approach of reconstructing VFD from traffic measurements in the vehicular coordinates. A smoothing algorithm is proposed to effectively reduce the nonphysical fluctuation of traffic states calculated from multilane vehicle trajectories. As an example, we apply the proposed methodology to explore the next‐generation simulation datasets and identify the existence and forms of shock waves in different coordinate systems. Our findings provide empirical justifications and further insight for the Lagrangian traffic flow theory and models when applied in practice. Copyright © 2015 John Wiley & Sons, Ltd.     

A new model for temporal–spatial stochastic analysis of vehicle–track coupled systems

The vehicle–track coupled system has a random nature in the time–space domain. This paper proposes a computational model to analyse the temporal–spatial stochastic vibrations of vehicle–track systems, where the vehicle–track system is divided into a vehicle subsystem, track subsystem, and interfacial subsystem between the wheel and rail. In this model, the time-varying randomicity of dynamical parameters of the vehicle system, correlation, and randomness of the track structural parameters in the time–space joint dimensions, and randomness of the track random irregularities are considered. A probability dimension-reduction method was used to randomly combine different random variables. Furthermore, the probability density evolution method was applied to solve the delivery problem of probabilities between excitation inputs and response outputs. The temporal–spatial stochastic vibrations of the vehicle–track system with different coefficients of variation were studied, in which we assumed that the dynamic parameters obeyed the normal distribution, and the stochastic simulation method of the track random irregularities is probed into. The calculated results from this model are consistent with the actual measured results and physical conceptions. Thus, the temporal–spatial stochastic evolutionary mechanism can be explored, and the limits of dynamic indices can be formulated by using this developed model.     

关于公交停靠站影响区范围的研究

随着城市公共交通系统的发展,公交停靠站对道路交通流的影响已逐渐引起人们的注意。分析公交停靠站的影响首先应该对停靠站的影响区范围进行界定。在分析前人研究成果的基础上,基于交通波理论,按考虑超车与否,分析公交停靠站的影响区范围长度,得到不同交通流密度条件下公交停靠站影响区长度的计算公式。