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   121篇
  免费   0篇
公路运输   31篇
综合类   20篇
水路运输   44篇
铁路运输   14篇
综合运输   12篇
  2024年   1篇
  2022年   3篇
  2021年   1篇
  2020年   3篇
  2019年   2篇
  2018年   1篇
  2017年   4篇
  2016年   5篇
  2015年   4篇
  2014年   7篇
  2013年   12篇
  2012年   10篇
  2011年   9篇
  2010年   4篇
  2009年   5篇
  2008年   7篇
  2007年   13篇
  2006年   7篇
  2005年   3篇
  2004年   5篇
  2003年   2篇
  2002年   2篇
  2001年   4篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1994年   1篇
排序方式: 共有121条查询结果,搜索用时 0 毫秒
61.
This research applied the Green Flag Program to assess the benefits of reducing speed and fuel transfer for large merchant vessels (bulk and container) entering Kaohsiung Port. This study adopts an activity-based model to calculate fuel consumption and emissions, as well as setting up two scenarios, (1) decrease vessel speed to 12 knots 20 nm away from port; and (2) decrease vessel speed to 12 knots and transfer fuel 20 nm away from port, which based on the Green Flag Program in Long Beach, in the U.S. The findings are (1) In scenario one, the container and bulk vessels saw reductions in CO2 emissions of about 41% and 14%, respectively. In scenario two, container and bulk vessels had reductions of about 48% and 43% in SO2 emissions, respectively. (2) Large vessels are more environmentally friendly than small vessels. (3) Using the CATCH model to assess the effectiveness of the two scenarios, it was found that container vessels benefited from both reducing speed and fuel transfer, while bulk carriers only did so from the former.  相似文献   
62.
概述了二甲醚汽车在国内外的发展现状,通过对二甲醚汽车特点和经济、社会效益的分析,认为发展二甲醚汽车无论在推广成本、产品安全性、经济性、还是在环保和产业带动等方面都有良好表现,值得社会关注并大力推广。  相似文献   
63.
In this work, a full-state feedback controller is designed to prevent the oscillatory instability or snaking behaviour of an articulated steer vehicle. To design the controller, first, a linearized model of the vehicle is developed and analyzed to identify the most important uncertain tire parameters with regard to the snaking mode. By using this linearized model, the equations of motion are represented in the form of a polytopic system, which depends affinely on the most important uncertain tire parameters. Then, by solving some linear matrix inequalities, both the Lyapunov and state feedback matrices for the robust stabilization of the vehicle are found. The performance of the resulting controller is evaluated by conducting several simulations based on the linearized model. To verify the results from the linearized model analysis, some simulations are also done by a virtual prototype of the vehicle in ADAMS. The results based on the linearized model are reasonably consistent with those from the simulations in ADAMS. They show that the controller can effectively stabilize the vehicle during the snaking mode in different driving conditions.  相似文献   
64.
This paper presents a real-time traffic network state estimation and prediction system with built-in decision support capabilities for traffic network management. The system provides traffic network managers with the capabilities to estimate the current network conditions, predict congestion dynamics, and generate efficient traffic management schemes for recurrent and non-recurrent congestion situations. The system adopts a closed-loop rolling horizon framework in which network state estimation and prediction modules are integrated with a traffic network manager module to generate efficient proactive traffic management schemes. The traffic network manger adopts a meta-heuristic search mechanism to construct the schemes by integrating a wide variety of control strategies. The system is applied in the context of Integrated Corridor Management (ICM), which is envisioned to provide a system approach for managing congested urban corridors. A simulation-based case study is presented for the US-75 corridor in Dallas, Texas. The results show the ability of the system to improve the overall network performance during hypothetical incident scenarios.  相似文献   
65.
陈登杰 《世界海运》2002,25(4):17-18
主要介绍了PSC检查中发现的主要缺陷,怎样做好接受PSC检查的准备工作和PSC检查时应注意的问题。  相似文献   
66.
毛泽东早期在改造国家的问题上,曾经吸收和借鉴过各种国内外进步思想。在接触马克思主义以前。青年毛泽东为探寻救国之路,对于世界上许多探求真理的思想家,特剐是近代中国进步思想家的思想和学说,都有过接触和研究,并在此基础上形成了其丰富独特的国家变革思想。  相似文献   
67.
This study aims to explore how factors including charging infrastructure and battery technology associate the way people currently charge their battery electric vehicles, as well as to explore whether good use of battery capacity can be encouraged. Using a stochastic frontier model applied to panel data obtained in a field trial on battery electric vehicle usage in Japan, the remaining charge when mid-trip fast charging begins is treated as a dependent variable. The estimation results obtained using four models, for commercial and private vehicles, respectively, on working and non-working days, show that remaining charge is associated with number of charging stations, familiarity with charging stations, usage of air-conditioning or heater, battery capacity, number of trips, Vehicle Miles of Travel, paid charging. However, the associated factors are not identical for the four models. In general, EVs with high-capacity batteries are initiated at higher remaining charge, and so are the mid-trip fast charging events in the latter period of this trial. The estimation results also show that there are great opportunities to encourage more efficient charging behavior. It appears that the stochastic frontier modeling method is an effective way to model the remaining charge at which fast-charging should be initiated, since it incorporates trip and vehicle characteristics into the estimation process to some extent.  相似文献   
68.
沉船的强制打捞清除是目前海事管理中一个存有争议和尚待解决的难点。通过对《残骸清除公约(草案)》中沉船强制打捞清除的定义、成立要件、实施及费用的实现等内容深入了解,越来越多的国家已认识到该公约的必要性和重要性,很多航运大国以及国际海事组织都在为公约的生效而积极努力。深入分析了该公约对沿海国、船旗国的权利、责任以及海上强制保险制度,并阐述对难点问题的建议和主张。  相似文献   
69.
Location-Based Social Networking (LBSN) services, such as Foursquare, Facebook check-ins, and Geo-tagged Twitter tweets, have emerged as new secondary data sources for studying individual travel mobility patterns at a fine-grained level. However, the differences between human social behavioral and travel patterns can cause significant sampling bias for travel demand estimation. This paper presents a dynamic model to estimate time-of-day zonal trip arrival patterns. In the proposed model, the state propagation is formulated by the Hawkes process; the observation model implements LBSN sampling. The proposed model is applied to Foursquare check-in data collected from Austin, Texas in 2010 and calibrated with Origin-Destination (OD) data and time of day factor from Capital Area Metropolitan Planning Organization (CAMPO). The proposed model is compared with a simple aggregation model of trip purposes and time of day based on a prior daily OD estimation model using the LBSN data. The results illustrate the promising benefits of applying stochastic point process models and state-space modeling in time-of-day zonal arrival pattern estimation with the LBSN data. The proposed model can significantly reduce the number of parameters to calibrate in order to reduce the sampling bias of LBSN data for trip arrival estimation.  相似文献   
70.
基于VHDL的有限状态机电路设计   总被引:1,自引:0,他引:1  
林若波 《中国水运》2007,5(9):210-212
有限状态机(FSM)及其应用技术是数字系统设计中的重要组成部分,基于VHDL的有限状态机设计已经成为EDA技术中的主要设计方法。论文通过对AD采样控制状态机的原理分析,介绍了基于VHDL平台的有限状态机的设计技术和实现过程。  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