非自治随机微分方程的均方伪概周期温和解

主要考虑Hilbert空间上非自治随机微分方程均方伪概周期解存在的唯一性.利用不动点定理并结合发展系统理论,给出了这类非自治随机微分方程均方伪概周期解唯一存在的充分条件.     

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为了全面描述决策者在不确定环境下的出行行为,从价值变化和可靠性变化两个方面研究通勤者的路径选择行为及对待风险的态度,提出了基于累积前景理论（CPT）的通勤者路径选择模型。首先推广了两个参考点的CPT,接着根据不确定理论对行程时间进行预算,给出通勤者参考点估计的统一方法,然后构造通勤者的路径选择模型。最后在一个测试网络上研究可靠度与参考点及可靠度与累积前景值的关系。结果表明,通勤者的参考点可以根据可靠度要求动态设置。出发时刻相同,出行者可靠度要求较高时,风险较低的路径前景值较大;反之可靠度要求较低时,行程时间平均值较小,虽然风险较高的路径前景值也比较大,这一结论与事实相符合。本文所提出的决策模型能够有效地描述通勤者在随机路网中的路径选择行为。     

Determination of the transportable moisture limit of iron ore fines for the prevention of liquefaction in bulk carriers

In 2013, over 500 million metric tons of Iron Ore Fines (IOF) were transported around the world using bulk carriers. Under certain conditions IOF, while being transported, can possibly undergo liquefaction. Since 2006, there has been eight reported bulk carrier casualties possibly caused by the liquefaction of IOF. The objective of this study is to evaluate, compare and verify the limitations and relevance of the Proctor/Fagerberg, Flow Table and Penetration test methods that are used to determine the Transportable Moisture Limit (TML) of IOF. The TML is the maximum gross water content that bulk cargoes, including IOF, may contain while being transported at sea without being at risk of liquefying. A thorough literature review, along with laboratory research, was carried out to compare the TML results from the three leading test methods to determine whether they produce reliable results when testing IOF. The study concludes that the three test methods, as stated in the 2012 International Maritime Solid Bulk Cargoes Code, are unverified and therefore not appropriate for testing IOF. This is due to the variation in the results produced by the three test methods and also due to the difference in the physical properties of IOF when compared with the materials that were originally intended for testing. It is noted that the TML alone may not control the potential liquefaction of IOF and further studies, regarding the physical properties and system variables, which cause the material to liquefy, are required to determine the liquefaction potential of IOF.     

一种优化的船体外板三维点云数据提取方法

针对水火弯板机检测系统中船舶外板三维点云数据自动提取过程存在边缘噪点、板下贴合垫木识别效率低以及外板边缘拟合等问题,提出一种优化DBSCAN聚类算法,首先根据现场加工环境精简点云,利用网格划分来建立外板点云拓扑模型,然后根据DBSCAN密度聚类算法搜索出外板点云,最后采用最小二乘法进行边缘拟合。结果表明,该算法能有效识别外板边缘,提取出外板点云。     

单点系泊FPSO系泊缆疲劳寿命研究

采用准动态方法对单点系泊FPSO进行系泊分析,并采用T-N曲线和Miner线性疲劳累积损伤理论以及雨流计数方法对系泊系统进行疲劳分析,研究每一根系泊缆不同位置处的疲劳寿命,研究发现每一根系泊缆触地点位置的疲劳寿命最短。     

达布定理的一个应用

应用达布定理,纠正了不定积分计算中的一个错误。     

探索港口发展现代物流的切入点

介绍了港口发展现代物流的两个切入点,即从宏观上切入,逐步提高港口的国际竞争能力;从微观上切入,稳步提高港口经济运行质量和效益。阐述了发展现代物流也是港口自身实现跨越式发展的必然途径和战略目标。     

城市道路水泥混凝土路面锯齿形偏沟设计方案

水泥混凝土路设计时,遇到设计纵坡小于0.3%,按规范要求设置锯齿形偏沟或采取其他排水措施,过去常采用缩短雨水口的间距办法,来解决排水问题,实际上此措施是不能很好地解决排水问题的.提出:仅在道路边缘50cm范围内设置偏沟的办法(水泥混凝土路面一般不设置平石),雨水口距离可保持40m,不再要加密雨水口,缩短雨水口的间距,同...     

Effect of the combined centre of gravity on the running safety of freight wagons

ABSTRACT

This paper presents an analysis of loaded freight wagon dynamics in curve alignments. We investigate the effects of the combined centre of gravity (CCOG) on the running safety of freight wagons and examine proper position of the CCOG. A simple wagon-rail model is implemented using the multibody dynamics software ADAMS/Rail. The simulation model is operated on curve tracks with various radii and velocities and the curving performances are evaluated. The results indicate that the CCOG can be located within a flexible and accurate range. The longitudinal offset is good for the curving performance and the permissible lateral offset should be assessed based on the curve radius and cant deficiency.     

美日汽车起动机性能指标解析

从起动机设计的角度，分析影响起动机主要性能指标的各项因素和调控规律。重点论述如何调整设计和制造工艺，使产品全面达到满足发动机和整车配套的技术要求。