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81.
地理信息系统在海运智能交通中的应用   总被引:7,自引:1,他引:6  
智能交通系统(ITS)是当前交通领域研究的热点,更是未来交通发展的方向。本文提出了海运智能交通系统的概念,分析了系统功能和构成。从海运交通的特点出发,以ECDIS为基础,对智能交通系统的重要组成部分-海运交通地理信息系统的处理模型、关键技术和方向进行了分析探讨。  相似文献   
82.
提高和改善大型集装箱船舶装载能力的探讨   总被引:1,自引:1,他引:0  
充分掌握大型集装箱船在满足船舶规范规定的适航、适货条件(船舶吃水、稳性、强度、系固、安全航行及适货要求),结合国际及国内有关法规及港口有关规定,提高和改善其装载能力,发挥更大经济效益是值得深入探讨的。  相似文献   
83.
几种肝脏食品中部分有害物质含量分析   总被引:4,自引:0,他引:4  
为了解动物肝脏食品的卫生质量,保障广大消费者的利益和健康,对南宁市10个主要农贸市场中销售的猪肝、牛肝、鸡肝及鸭肝共37份样品进行了黄曲霉毒素Bl及有害元素铅、汞、镉、砷的检测。结果表明:4种肝脏食品中黄曲霉毒素Bl均未检出,有害元素汞、砷的含量也符合相应的国家卫生标准,但镉与铅含量较高,其均值分别为0.149及0.703mg/kg,超出了我国的食品卫生标准,其中主要是鸭肝和猪肝受污染严重,而牛肝的卫生质量相对较好。提示目前在动物肝脏食品中存在着一定的有害元素镉、铅的污染,应引起有关管理部门的注意。  相似文献   
84.
This paper describes a simplified methodology designed for quick investment appraisal of improvements to a transport network, and discusses its limitations and advantages particularly in the context of a developing country. The approach basically considers:
  • - a method to define the total population (relevant origin-destination pairs) affected by the project
  • - the selection of a low-cost background model to represent transport demand on a network at an aggregate level
  • - the choice of a suitable marginal demand model (in this case a discrete mode choice model) capable of providing the required sensitivity and accuracy to model the project
  • - the estimation of the marginal demand due to the project during all the years of the study horizon, and
  • - a sensitivity analysis to assess the robustness of the decision recommended using these two models.
  • Finally, the paper summarises the results of applying the methodology to the case of an extension to the Santiago underground; it was found that the project has a high social rate of return (almost 20 per cent). However, from the point of view of a private evaluation, it can cover its operating costs only.  相似文献   
    85.
    Over the past decades research on travel mode choice has evolved from work that is informed by utility theory, examining the effects of objective determinants, to studies incorporating more subjective variables such as habits and attitudes. Recently, the way people perceive their travel has been analyzed with transportation-oriented scales of subjective well-being, and particularly the satisfaction with travel scale. However, studies analyzing the link between travel mode choice (i.e., decision utility) and travel satisfaction (i.e., experienced utility) are limited. In this paper we will focus on the relation between mode choice and travel satisfaction for leisure trips (with travel-related attitudes and the built environment as explanatory variables) of study participants in urban and suburban neighborhoods in the city of Ghent, Belgium. It is shown that the built environment and travel-related attitudes—both important explanatory variables of travel mode choice—and mode choice itself affect travel satisfaction. Public transit users perceive their travel most negatively, while active travel results in the highest levels of travel satisfaction. Surprisingly, suburban dwellers perceive their travel more positively than urban dwellers, for all travel modes.  相似文献   
    86.
    Rail-road crossings generate a range of transport, economic, social and environmental impacts. While much research has focused on selected impacts such as safety, little consideration has been given to wider impacts. The aim of this research was to therefore develop a holistic understanding of the impacts of rail-road crossings (both at-grade and grade-separated) and to identify key gaps in knowledge in this field. An international synthesis of rail-road crossing impacts was developed through a detailed literature review, which revealed a total of 18 different types of impacts associated with rail-road crossings. The review found that most research to date has focused on quantifying transport and economic impacts, particularly safety and road vehicle delay, with little consideration given to social and environmental impacts. A number of research gaps have been identified which provide a clear agenda for future research. These gaps include the use of empirical evidence to support impact assessments, and the need to better understand the impacts of grade-separating rail-road crossings in terms of safety, travel time variability, land use, traffic flow, rail vehicle delay, disability access, and crime.  相似文献   
    87.
    论宪法的控权本质   总被引:4,自引:0,他引:4  
    现代法治最本质的精神和特点就是控权。在现代法治国家,法治的控权功能首先由宪法确立并由宪法所保障。并成为宪法的核心内容。没有控权就没有宪法,没有宪法也没有控权。宪法的控权本质是宪法作为根本法的前提和依据。宪法作为根本法就因为它是控权法。反之,宪法如果没有控权功能,就会失去根本法的地位。宪法的控权本质在中国长期不受重视。中国宪法学界的“多重本质论”在很大程度上削弱了宪法的控权本质,从而影响了中国宪法的实施。中国的宪政建设不仅面临宪法观念的突破,而且面临控权制度的建设。  相似文献   
    88.
    预应力锚索抗滑桩的动态设计法   总被引:11,自引:0,他引:11  
    提出了预应力锚索抗滑桩的动态设计概念,即跟踪锚索桩的实际工作状况,分析桩和锚索在各种受荷条件下的内力,再进行优化组合,以其中的最大内力为依据进行桩结构设计和锚索承载力设计,对锚索预应力值的确定问题进行了探讨,算例分析表明,本文中的设计方法能反映桩的最危险状态,使锚索和桩留有合理的安全储备。对锚索桩长期正常工作有利。  相似文献   
    89.
    论文将锥头射弹侵彻贯穿金属薄靶板的耗能分为整体和局部耗能两部分。基于空腔膨胀理论,给出了靶板对射弹的阻力表达式,然后计算出局部变形耗能。根据量纲分析和相似原理,由搜集到的弹道试验数据拟合求得整体变形耗能,推出了射弹穿透金属靶板的弹道极限公式。并将模型预测结果和数值仿真分析的结果进行了比较分析。  相似文献   
    90.
    The two main value propositions in international container transport are ‘port-to-port’ services and ‘door-to-door’ services. In port-to-port services, buyers ‘just’ purchase maritime transport from a shipping line. Door-to-door services comprise the total transport chain and include land-based transport. Carriers as well as forwarders offer these door-to-door services. In this paper we provide a qualitative assessment of an emerging third value proposition that is centred around inland terminals (ILTs). Such a value proposition consists of transport up to the ILT, and may have advantages over port-to-port services, such as better leverage of scale economies, better repositioning of empty containers and better alignment with the business model of forwarders. This paper conceptually and empirically explores such a value proposition.  相似文献   
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