碳纤维布加固钢筋混凝土梁挠度的一种计算方法

本文研究了碳纤维布加固性能,利用钢筋混凝土结构设计中的梁理论,推导并验算了粘贴碳纤维布加固钢筋混凝土梁挠度的计算公式方法,分析了影响碳纤维布加固钢筋混凝土梁挠度值大小的因素。     

有软弱夹层岩体边坡的稳定性评价

对发育多个规则软弱夹层的岩体边坡稳定性评价方法进行了探讨。在塑性极限分析的基础上，采用机动位移法，提出可以用能量系数作为稳定性评价的标准，并推导了相应公式。通过川藏公路上一个典型滑坡实例的稳定性分析，与极限平衡法进行了对比，证明了本方法的可行性。     

A test of the two-mode UMOT in the Netherlands

The UMOT model, presented as an alternative to conventional travel demand models, is critically examined for its feasibility to predict vehicle distance travelled and average daily traffic in The Netherlands. Using data from the National Travel Survey (OVG) 1978 a Dutch version of UMOT is developed, and an attempt is made to validate it on historical data from the period 1960 to 1980. Some comparisons are made with results of similar work using 1976 survey data in the UK by the Transport and Road Research Laboratory.     

航海教育模式及航海院校管理体制的比较研究

随着ＳＴＣＷ 新公约的生效和实施,航海教育改革在世界范围展开。本文从航海教育模式和院校管理体制两个视角比较研究国内外航海教育的经验和特点,阐述中国航海教育改革的必要性和迫切性     

The ‘safety in density’ effect for cyclists and motor vehicles in Scandinavia: An observational study

Safety in density (SID) potentially explains the safety in numbers (SIN) phenomenon by positing that ‘the SIN effect can be reproduced simply through encouraging behaviour that leads to the formation of higher-density cyclist groups’. The study further explores this hypothesis using event-based exposure, queues and groups of road users. Using three different definitions of encounters between road users, these were manually counted at signalized intersections, and their relationship to traffic volume was assessed. Based only on the frontmost motor vehicle in a queue and one cyclist among the several passing in front of that vehicle, the results show a less than linear relationship between meetings and traffic volume. An increase in the number of cyclists entails a general increase in cyclists passing in front of each motor vehicle, and an increase in motor vehicles increases queue lengths. However, crash data from the Swedish accident database (STRADA) show that it is exceedingly rare for multiple cyclists to be injured in the same crash. Together with results from a crash-encounter model, this suggests that the SID hypothesis may help to explain SIN     

Experimental investigations on continuous regenerative anti-lock braking system of full electric vehicle

Functions of anti-lock braking for full electric vehicles (EV) with individually controlled wheel drive can be realized through conventional brake system actuating friction brakes and regenerative brake system actuating electric motors. To analyze advantages and limitations of both variants of anti-lock braking systems (ABS), the presented study introduces results of experimental investigations obtained from proving ground tests of all-wheel drive EV. The brake performance is assessed for three different configurations: hydraulic ABS; regenerative ABS only on the front axle; blended hydraulic and regenerative ABS on the front axle and hydraulic ABS on the rear axle. The hydraulic ABS is based on a rule-based controller, and the continuous regenerative ABS uses the gain-scheduled proportional-integral direct slip control with feedforward and feedback control parts. The results of tests on low-friction road surface demonstrated that all the ABS configurations guarantee considerable reduction of the brake distance compared to the vehicle without ABS. In addition, braking manoeuvres with the regenerative ABS are characterized by accurate tracking of the reference wheel slip that results in less oscillatory time profile of the vehicle deceleration and, as consequence, in better driving comfort. The results of the presented experimental investigations can be used in the process of selection of ABS architecture for upcoming generations of full electric vehicles with individual wheel drive.     

季节冻土区高速公路路基冻胀试验观测研究

在季节性冻土区的路基工程中．冻胀是冻害的主要形式之一．冬季较强烈的冻胀也预示着春季可能要产生较严重的融沉和翻浆。根据2000～2002年间对吉林省长余高速公路路基冻张观测所获得的资料．描述了冻胀引起的路面变形破坏特征,对影响冻胀的因素进行了分析．并阐明了路基冻胀量沿冻深的分布状况。     

可预见的无故障切削

每一个加工工艺的目标应该是在保持高生产率和低生产成本的同时,尽可能提高安全性和可预见性。为此,需要考虑以下几个因素：工件的材料、形状和尺寸、机床、CAM系统、工件和刀具的夹紧、切削刀具的选择及使用情况（见图1）。     

整平推进阻力及支腿钢垫板摩擦系数实测试验

为完成离岸深水港抛石基床整平关键技术研究课题,设计制作了专用试验装置,对采用料仓摊铺方式进行整平的推进阻力和钢质垫板与抛石基床之间的摩擦系数进行了实测,总结了试验结果,为整平机的设计提供参数.