首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   93篇
  免费   0篇
公路运输   14篇
综合类   25篇
水路运输   4篇
铁路运输   3篇
综合运输   47篇
  2022年   1篇
  2021年   2篇
  2019年   1篇
  2018年   4篇
  2016年   2篇
  2015年   1篇
  2014年   4篇
  2013年   7篇
  2012年   4篇
  2011年   5篇
  2010年   4篇
  2009年   9篇
  2008年   16篇
  2007年   7篇
  2006年   2篇
  2005年   1篇
  2004年   1篇
  2002年   1篇
  2000年   3篇
  1999年   1篇
  1998年   1篇
  1995年   2篇
  1994年   1篇
  1993年   4篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1981年   1篇
  1978年   1篇
  1977年   1篇
  1974年   2篇
排序方式: 共有93条查询结果,搜索用时 15 毫秒
41.
Potential benefits of an adaptive forward collision warning system   总被引:1,自引:0,他引:1  
Forward collision warning (FCW) systems can reduce rear-end vehicle collisions. However, if the presentation of warnings is perceived as mistimed, trust in the system is diminished and drivers become less likely to respond appropriately. In this driving simulator investigation, 45 drivers experienced two FCW systems: a non-adaptive and an adaptive FCW that adjusted the timing of its alarms according to each individual driver’s reaction time. Whilst all drivers benefited in terms of improved safety from both FCW systems, non-aggressive drivers (low sensation seeking, long followers) did not display a preference to the adaptive FCW over its non-adaptive equivalent. Furthermore, there was little evidence to suggest that the non-aggressive drivers’ performance differed with either system. Benefits of the adaptive system were demonstrated for aggressive drivers (high sensation seeking, short followers). Even though both systems reduced their likelihood of a crash to a similar extent, the aggressive drivers rated each FCW more poorly than their non-aggressive contemporaries. However, this group, with their greater risk of involvement in rear-end collisions, reported a preference for the adaptive system as they found it less irritating and stress-inducing. Achieving greater acceptance and hence likely use of a real system is fundamental to good quality FCW design.  相似文献   
42.
This research is the first to develop a design for a powertain system of a plug-in parallel diesel hybrid electric bus equipped with a continuously variable transmission (CVT) and presents a new design paradigm of the plug-in hybrid electric bus (HEB). The criteria and method for selecting and sizing powertrain components equipped in the plug-in HEB are presented. The plug-in HEB is designed to overcome the vulnerable limitations of driving range and performance of a purely electric vehicle (EV) and to improve fuel economy and exhaust emissions of conventional bus and conventional HEBs. The control strategy of the complicated connected propulsion system in the plug-in parallel HEB is one of the most significant factors in achieving higher fuel economy and lower exhaust emissions of the HEV. In this research, a new optimal control strategy concept is proposed against existing rule-based control strategies. The optimal powertrain control strategy is obtained through two steps of optimizations: tradeoff optimization for emission control and energy flow optimization based on the instantaneous optimization technique. The proposed powertrain control strategy has the flexibility to adapt to battery SOC, exhaust emission amount, classified driving pattern, driving condition, and engine temperature. The objective of the optimal control strategy is to optimize the fuel consumption, electricity use, and exhaust emissions proper to the performance targets. The proposed control strategy was simulated to prove its validity by using analysis simulation tool ADVISOR (advanced vehicle simulator).  相似文献   
43.
Abstract

Since 1990s the liner shipping industry has faced a period of restructuring and consolidation, and been confronted with a continuing increase in container vessel scale. The impact of these changes is noticeable in trade patterns, cargo handling methods and shipping routes, in short ‘operations’. After listing factors influencing size, growth in container ship size is explained by economies of scale in deploying larger vessels. In order to quantify economies of scale, this paper uses the liner service cash flow model. A novelty in the model is the inclusion of +6000-20-foot Equivalent Unit (TEU) vessels and the distinction in costs between single and twin propeller units on ships. The results illustrate that scale economies have been – and will continue to be – the driving force behind the deployment of larger container vessels. The paper then assesses the link between ship size and operations, given current discussions about the increase in container vessel scale. It is found that (a) ship size and operations are linked; (b) optimal ship size depends on transport segment (deep-sea vs. short-sea shipping, SSS), terminal type (transhipment terminals vs. other terminals), trade lane (East-West vs. North-South trades) and technology; and (c) a ship optimal for one trade can be suboptimal for another.  相似文献   
44.
装备两台康明斯-水星QSC型8.3升540马力全电控船用发动机、燃用B100生物柴油(100%的生物柴油)的“环球竞赛号(Earthrace)”高速环保机动船6月27日抵达西班牙萨贡托港,结束了为期60天23小时49分钟的环球航程,从而打破英国高速船“大东电报号(Cable&Wireless)”十年前创下的74天20小时58分钟纪录。  相似文献   
45.
康明斯公司日前发布了三季度财务公报,销售额和利润再创新高。三季度的大好形势主要归因于国际业务的强劲增势.有效抵消了北美消费品市场持续走低和欧洲市场疲软带来的负面影响。  相似文献   
46.
47.
康明斯日前联手戴克公司和美国联邦环保署(EPA),共同在美国首都华盛顿向业界展示了当前全球排放最低、功率最强而且噪音最低的6.7升涡轮增压柴油机,这款新一代发动机专为克莱斯勒公司的2500和3500型道奇公羊重型皮卡配套.  相似文献   
48.
一年一度的美国中部地区卡车展览会(Mid America Truck Show)于今年3月19~21日在肯塔基州路易斯维尔如期举行,康明斯展出了全系列满足EPA 2010排放标准的中马力(6.7、8.3和9升)和重型柴油机(11.9升和15升)产品.  相似文献   
49.
For highly automated driving in urban regions it is essential to know the precise position of the car. Furthermore it is important to understand the surrounding context in complex situations, e.g. multilane crossings and turn lanes. To understand those situations there is not only the task to detect the lane border, but to detect the painted information inside the lane. The paper is facing and evaluating two methods to classify this additional lane information. Therefore the images from five cameras mounted around the car are used. Four of them with fisheye lenses. The methods have in common, that the input images are transformed into a bird view projection. First introduced method is to extract contours from the transformed images and collect geometrical features and Fourier coefficients. The second introduced way, is to calculate histograms of oriented gradients and use it as input for the classification step. Both classification approaches are implemented and evaluated as multiclass and single class detectors for each arrow type. Furthermore, the classification results from a support vector machine and random forest were faced for this classification problem. The results from the multiclass detectors are evaluated and presented in form of confusion matrices. With the introduced approaches a high detection confidence could be achieved, proofed with validation datasets and in practical use.  相似文献   
50.
One important parameter influencing mixture formation and spray/wall interaction within engines is the geometry of the nozzle. In contrast to Diesel nozzles, the influence of the orifice geometry on spray formation has hardly be investigated for gasoline nozzles. In order to demonstrate the potential of adjusting the nozzle geometry of a modern GDI nozzle, we compare two six-hole, high-pressure nozzles with an identical structure, but different rounding radius of the orifice hole-inlet and different orifice hole-geometries: nozzle A with a rounded inlet and an orifice length to diameter ratio of 3/2 and nozzle B with a sharp inlet and an orifice length to diameter ratio of 1. In a first measurement campaign the spray formation is visualized using high-speed shadowgraphy imaging. The results show differences in spray angle and penetration depth. In a second measurement campaign we examine the spray/wall interaction and wall film formation by means of infrared thermography. The thermography measurements indicate that the geometry of nozzle B produces sprays with beneficial characteristics. This is very important for a clean combustion process and a decrease of soot emissions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号