海洋立管的模态及参数敏感性分析

为分析海洋立管受不同形式的轴向张力作用时的模态求解问题,用哈密尔顿原理建立理论模型,讨论模态的计算方法,并分析相关参数对结果的影响。结果表明,在相同的张力因子下,随着立管长度增大其固有频率主要受张力的控制;在深水中因表观重力引起的沿轴向张力的线性变化不可忽略,对频率和振型都有重要影响,张力因子的增大使频率提高,这种影响对结构长度变化敏感;频率随附加水质量系数的增大而降低。     

Multilane first-order traffic flow model with endogenous representation of lane-flow equilibrium

In this study, we develop a multilane first-order traffic flow model for freeway networks. In the model, lane changing is considered as a stochastic behavior that can decrease an individual driver’s disutility or cost, and is represented as dynamics toward the equilibrium of lane-flow distribution along with longitudinal traffic dynamics. The proposed method can be differentiated from those in previous studies because in this study, the motivation of lane changing is explicitly considered and it is treated as a utility defined by the current macroscopic traffic state. In addition, the entire process of lane changing is computed macroscopically by an extension of the kinematic wave theory employing IT principle; moreover, in the model framework, the lane-flow equilibrium curve is endogenously generated because of self-motivated lane changes. Furthermore, the parsimonious representation enables parameter calibration using the data collected from conventional loop detectors. The calibration of the data collected at four different sites, including a sag bottleneck, on the Chugoku expressway in Japan reveals that the proposed method can represent the lane-flow distribution of any observation site with high accuracy, and that the estimated parameters can reasonably explain the multilane traffic dynamics and the bottleneck phenomena uphill of sag sections.     

On macroscopic freeway merge behavior: Estimation of merge ratios using asymmetric lane flow distribution

Data from several freeway merges reveal that, contrary to some previous findings, merge ratio can vary within a site with respect to the merge outflow and that the existing merge ratio estimates based on lane counts are not able to predict this within-site variation. Furthermore, the merge ratios estimated based on two well-known merging principles, “fair-share” and “zipper,” are found to be inaccurate for merges where merging streams compete directly due to a lane drop. In light of these findings, we estimate merge ratios using lane flow distribution (LFD) to better predict between and within site variations of merge ratio. In addition, we propose a merging principle specific for merges with a single lane-drop. The model was developed to better represent observed non-uniform redistribution of merging flow not captured by the current merge ratio estimation methods and merging principles. Empirical observations show that the proposed methods are able to improve merge ratio estimates, reproduce within-site variations of merge ratio, and represent more accurately non-uniform redistribution of merging flow dependent on the merge geometry.     

小缸径低速柴油机加装EcoEGR系统设计与布置

某型火车滚装船布置2台小缸径低速柴油机加装经济型废气再循环（Economical Exhaust Gas Recirculation，EcoEGR）系统，以满足Tier Ⅲ排放要求。以该船为依托，对该类型主机及相应船舶管路与控制系统的原理设计、实船布置等进行介绍和深入分析，为后续或类似船舶的小缸径低速柴油机加装EcoEGR系统及设备设计与建造提供有价值的参考。     

哈五公路声屏障设计原理

结合工程实例介绍了哈五公路声屏障的设计原理、结构、安全性和适应性等,指出了消除噪声污染在经济发展中的重要意义。     

冲击式压路机在伊嘉公路五汤段路基施工中的应用

简要介绍了冲击式压路机的工作原理和在路基施工中对提高压实度,减少沉降量的作用机理及其应用效果。     

可缩回式前照灯结构、原理及维护

通过对可缩回式前照灯特点的分析,详细阐述了其组成结构、工作原理以及维护措施等相关事项。     

复合材料薄壁杆件非线性扭转分析

考虑几何非线性的影响，建立了在拉、压、弯、扭组合变形下复合材料薄壁杆件理论．重点对杆件进行非线性扭转分析，由给出的等效本构方程和总势能泛函，根据最小势能原理导出了所给问题的平衡控制方程和相应边界条件．讨论了该方程和边界条件的求解．     

模糊粗糙集的表示定理

通过对偶方式定义了模糊集的上、下近似算子，给出了模糊粗糙集在相应的模糊关系及模糊集的截集下的表示定理，证明了这种模糊粗糙集关于模糊近似空间的上近似恰为其在二元模糊相似关系下导出的广义扩张原理之下的像。证明了Zadeh模糊推理合成规则(CRI)与特定的广义扩张原理具有相同的形式。推理结果也可由此获得，这样可借助广义扩张原理的性质及粗糙集理论研究模糊推理．