内河船员理论考试试题的设计与开发

文章针对船员考试题型设计给出了新的思路,提出用多媒体试题来改革、补充和替代传统文本卷面的考试形式,具有较高的应用价值,对推动海事主管部门的考试改革、提高船员队伍素质具有一定的建设意义。     

某试验路段冲击碾压技术与孔隙水压力监控

在公路路基施工碾压过程中,每轮冲碾的时间间隔是一个重要的施工参数。考虑到现场条件的不便,通过实测数据重点分析孔隙水压力和地下水位的时变规律,提出用反算现场频率来指导冲碾施工的方法,对同类工程施工具有一定的参考价值。     

对于哈尔滨市地区道路结构适用性的比选研究

从哈尔滨市常用筑路材料的特性入手,系统介绍了该地区的常用道路结构组合,通过对其弯沉、拉应力、容许拉应力等检测指标及造价的分析比较,提出了各种道路结构的适用性、缺点,给出了适用于哈尔滨市地区的道路结构方案。     

摩托车燃油蒸发标准对比研究(1)

虽然世界不同国家和地区采用的摩托车燃油蒸发标准不尽相同,但所要达到的目的是一致的,就是在摩托车保有量大幅增长的同时,最大限度地降低对环境造成的污染并节约燃油能源,改善生态环境.据资料显示,通过GB 20998-2007标准的实施,我国摩托车年燃油蒸发量每年减少约100 000t.     

传动系统撞击现象的分析与优化

针对某后置后驱电动客车在收油门工况下产生的撞击问题,进行了整车试验测试.通过同步采集传动系统不同位置的噪声、振动以及转速信号,对撞击现象进行描述,并辨识撞击发生位置.以撞击持续时间内的信号RMS值作为评价指标,探究悬置以及齿轮副间隙对撞击剧烈程度的影响.从降低传动系统扭矩变化速率的角度出发,提出了优化撞击问题的措施.优...     

汽车液压感载比例阀性能试验台的研制

根据汽车感载比例阀的技术要求和检测方法,研制了液压感载比例阀性能试验台,介绍了该试验台及其控制系统的组成和功能。实际测试结果表明,该试验台测试精度高、性能稳定、装卸被测试件快速准确、测试时间短、测试结果可视化程度高、历史数据查询方便,可为液压感载比例阀的研制和在线检测提供可靠的测试依据和试验手段。     

客车涂层表观质量的测量评估及工艺优化

主要介绍影响客车涂层表观质量的光泽、雾影、桔皮、鲜映性、颜色等指标的测试原理和相应测试仪器,并从工艺角度探讨如何改善涂层表观质量.     

具有反馈检测功能的地铁列车开关门试验装置设计

传统地铁列车开关门试验装置,在试验过程中需工作人员确认地铁列车操纵台上的门全关指示灯是否点亮,检测效率较低.针对这种现状,设计一种具有反馈检测功能的地铁列车开关门试验装置.试验装置集成电路硬件以STM32F103C8T6型号的ARM芯片为控制核心,外围配置二极管、三极管、OLED12864显示屏、板载继电器和接线端子等...     

Required test durations for converged short-term wave and impact extreme value statistics–Part 2: Deck box dataset

In the assessment of wave-in-deck loads for new and existing maritime structures typically model tests are carried out. To determine the most critical conditions and measure sufficient impact loads, a range of sea states and various seeds (realisations) for each sea state are tested. Based on these measurements, probability distributions can be derived and design loads determined. In air gap model testing usually only few, if any, impact loads occur per 3-hour seed. This can make it challenging to derive reliable probability distributions of the measured loads, especially when only a few seeds are generated. In addition wave impact forces, such as greenwater loading, slamming, or air gap impacts are typically strongly non-linear, resulting in a large variability of the measured loads. This results in the following questions: How many impacts are needed to derive a reliable distribution? How is the repeatability of individual events affecting the overall distribution? To answer these questions wave-in-deck model tests were carried out in 100 x 3-hour realisations of a 10,000 year North Sea sea state. The resulting probability distributions of the undisturbed wave measurements as well as the measured wave-in-deck loads are presented in this paper with focus on deriving the number of seeds and exposure durations required for a reliable estimate of design loads.The presented study is Part 2 of a combined study on guidance for the convergence and variability of wave crests and impact loading extreme values. The data set of Part 1 ([1]) is based on greenwater loads on a sailing ferry and the data set of Part 2 on wave-in-deck loads on a stationary deck box.