20万吨级绿色环保型散货船开发与设计

介绍了针对市场需求设计开发的20万吨级绿色环保散货船的基本概况、设计特点和主要要素.特别介绍了该船在线型优化、节能附体、主机选型优化、NOx、SOx、压载水处理系统等方面的独特设计,使该船成为真正意义上的“绿色船舶”.     

Real time queue length estimation for signalized intersections using travel times from mobile sensors

We study how to estimate real time queue lengths at signalized intersections using intersection travel times collected from mobile traffic sensors. The estimation is based on the observation that critical pattern changes of intersection travel times or delays, such as the discontinuities (i.e., sudden and dramatic increases in travel times) and non-smoothness (i.e., changes of slopes of travel times), indicate signal timing or queue length changes. By detecting these critical points in intersection travel times or delays, the real time queue length can be re-constructed. We first introduce the concept of Queue Rear No-delay Arrival Time which is related to the non-smoothness of queuing delay patterns and queue length changes. We then show how measured intersection travel times from mobile sensors can be processed to generate sample vehicle queuing delays. Under the uniform arrival assumption, the queuing delays reduce linearly within a cycle. The delay pattern can be estimated by a linear fitting method using sample queuing delays. Queue Rear No-delay Arrival Time can then be obtained from the delay pattern, and be used to estimate the maximum and minimum queue lengths of a cycle, based on which the real-time queue length curve can also be constructed. The model and algorithm are tested in a field experiment and in simulation.     

A link-node complementarity model and solution algorithm for dynamic user equilibria with exact flow propagations

In this paper, we propose a link-node complementarity model for the basic deterministic dynamic user equilibrium (DUE) problem with single-user-class and fixed demands. The model complements link-path formulations that have been widely studied for dynamic user equilibria. Under various dynamic network constraints, especially the exact flow propagation constraints, we show that the continuous-time dynamic user equilibrium problem can be formulated as an infinite dimensional mixed complementarity model. The continuous-time model can be further discretized as a finite dimensional non-linear complementarity problem (NCP). The proposed discrete-time model captures the exact flow propagation constraints that were usually approximated in previous studies. By associating link inflow at the beginning of a time interval to travel times at the end of the interval, the resulting discrete-time model is predictive rather than reactive. The solution existence and compactness condition for the proposed model is established under mild assumptions. The model is solved by an iterative algorithm with a relaxed NCP solved at each iteration. Numerical examples are provided to illustrate the proposed model and solution approach. We particularly show why predictive DUE is preferable to reactive DUE from an algorithmic perspective.     

铁路电力配电所跨所供电设计面面观

对铁路电力配电所跨所供电条件进行设计探讨。通过对有关铁路设计规范与铁路运行规程的比较,指出存在的问题。从设计与运行的角度,对配电所跨所供电进行技术、经济、可靠性、节能方面的分析,客观指出配电所跨所供电的利弊,以及设计中应该注意的事项,并对配电所跨所供电提出建议。     

强化水旋澄清池技术处理高浊度黄河水的研究

分析了常规水旋澄清池处理工艺.提出了增加投药器、改变投药方式和改造水旋澄清池进水方式的强化措施.实验结果表明,水旋澄清池经强化技术改造后,黄河水中浊度、有机物、氨氮的去除率均有了较大提高.为水厂在黄河水较高浊度期的正常供水提供了技术保障.     

车门内把手设计开发

本文通过归纳分析车门内把手的典型结构形式、其与周边相关各部件的匹配关系及其试验验证方法,提出了车门内把手设计流程及思路,总结了车门内把手设计开发方法及要点,以保证车门内把手开发的准确性。     

襄渝铁路二线马鞍山隧道出口段围岩变形监测

以马鞍山隧道施工为例,从监测项目、测点布置、管理标准、预警制度及监测实施等方面,论述了围岩监测不仅是实施信息化所必须,且为隧道的安全施工提供了可靠信息和决策依据。     

拥挤定价理论发展及对我国城市交通管理的启示

拥挤定价作为城市交通需求管理的重要组成部分,是交通经济学的核心内容之一。本文综述了拥挤定价理论的发展历程和最新进展,提出了该领域的研究方向,分析了拥挤定价理论在实践中的应用效果,给出了我国推行该政策的建议,拥挤定价的实践表明该政策在控制交通流方面效果显著,该政策是否具有可操作性取决于公众的态度,这将是我国大中城市推行该政策的基本出发点和难点。     

低质量船舶存在的问题及应对的对策

低质量船舶指无审批图纸或未按图施工,或造船工艺达不到船检法规和规范要求,或建造质量低劣,或未完成必须的建造检验项目而生产出来的船舶.近年来,随着国内水运经济的发展,造船业兴旺,沙滩、滩涂造船在一些地区发展迅速,大量的低质量船舶涌入航运市场,成为水上安全的重大隐患。