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   19篇
  免费   1篇
公路运输   6篇
综合类   1篇
水路运输   4篇
铁路运输   1篇
综合运输   8篇
  2021年   2篇
  2017年   1篇
  2015年   2篇
  2014年   1篇
  2013年   1篇
  2012年   3篇
  2011年   4篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2005年   1篇
  2003年   1篇
  1995年   1篇
排序方式: 共有20条查询结果,搜索用时 234 毫秒
1.
We report on an intensive campaign in the summer of 2006 to observe turbulent energy dissipation in the vicinity of a tidal mixing front which separates well mixed and seasonally stratified regimes in the western Irish Sea. The rate of turbulent dissipation ε was observed on a section across the front by a combination of vertical profiles with the FLY dissipation profiler and horizontal profiles by shear sensors mounted on an AUV (Autosub). Mean flow conditions and stratification were obtained from a bed mounted ADCP and a vertical chain of thermistors on a mooring. During an Autosub mission of 60 h, the vehicle, moving at a speed of ~ 1.2 m s− 1, completed 10 useable frontal crossings between end points which were allowed to move with the mean flow. The results were combined with parallel measurements of the vertical profile of ε which were made using FLY for periods of up to 13 h at positions along the Autosub track. The two data sets, which show a satisfactory degree of consistency, were combined to elucidate the space–time variation of dissipation in the frontal zone. Using harmonic analysis, the spatial structure of dissipation was separated from the strong time dependent signal at the M4 tidal frequency to yield a picture of the cross-frontal distribution of energy dissipation. A complementary picture of the frontal velocity field was obtained from a moored ADCP and estimates of the mean velocity derived from the thermal wind using the observed density distribution. which indicated the presence of a strong (0.2 m s− 1) jet-like flow in the high gradient region of the front. Under neap tidal conditions, mean dissipation varied across the section by 3 orders of magnitude exceeding 10− 2 W m− 3 near the seabed in the mixed regime and decreasing to 10− 5 W m− 3. in the strongly stratified interior regime. The spatial pattern of dissipation is consistent in general form with the predictions of models of tidal mixing and does not reflect any strong influence by the frontal jet.  相似文献   
2.
电动小车     
MINI品牌和SMART品牌异口同声地问道——如今城市中的年轻人到底想要些什么?两家公司都得出了同一个结论——不会是汽车。你也许会认为,这个结论对于两大时尚汽车品牌来说是个大麻烦,但他们却不苟同。两大品牌一致认为,年轻人可以先使用他们出品的电动踏板车,以此来尝鲜,等到有了足够经济实力之时,再去购买汽车。两大品牌都在着手让电动踏板车可以用你的iPhone来进行操纵。MINI品牌背后  相似文献   
3.
Resilience theory has management implications useful when planning for cruise ship tourism. In small coastal communities, cruise ships often provide welcomed economic incentives that can bolster a waning economy. However, in some coastal communities, the magnitude and intensity of passenger visits can reduce social resilience and induce an economic regime shift that leads to rapid socioeconomic reorganization. The implications of such a regime shift are a loss of economic diversity, reduced social resilience, and a loss of social capital. Planning for cruise ship resilience increases the likelihood of successful coping strategies and addresses the socioecological changes inherent to a cruise ship destination. Both Holling's adaptive cycle and the four principals for building resilience established by Berkes and Seixas are fundamental to a successful management plan.  相似文献   
4.
这是一个严肃的命题。作为艺术界的"饱学之士",龚福尔现代艺术中心(Confort Moderne)将通过SarahBraman的雕塑传达一种"针对近期某些愤世嫉俗的知识分子言论以及带有自我反省色彩的玄妙语言而作出的救赎性反应"。我可以向你保证,有许多理由足以促使你去普瓦捷(Poitiers)参观这位美国艺术家的展览!首先,你可以看到各种  相似文献   
5.
Integrated land use and transportation forecasting models are used to assist decision-makers in the policy analysis and infrastructure capital improvement selection process. These models are typically given precise, point-estimate inputs that are mathematically linked, through a series of submodels, to forecasted model outputs. These point-estimate inputs represent an unrealistic level of precision and a growing body of research is focusing on statistical techniques to model uncertainty in model inputs and parameters and tracking the effects of this uncertainty through the various submodels to the model outputs. This paper presents an uncertainty analysis of the Large Zone Economic Module (LZEM) of the Simple, Efficient, Elegant, and Effective Model (SE3M) of land use and transportation. Three case-study implementations of the model are used to obtain a reasonably sound approximation of how uncertainty affects LZEM outputs: Guam, Puerto Rico, and Oahu, Hawaii. These case studies were the subject of an early transferability study with SE3M and were selected based on both their insularity and diverse physical, economic, and demographic geographies. The findings of this research demonstrate that LZEM has a robust framework, with the potential to estimate error both in the positive and negative direction under uncertain input/parameter conditions.  相似文献   
6.
RELU-TRAN2, a spatial computable general equilibrium (CGE) model of the Chicago MSA is used to understand how gasoline use, car-VMT, on-the-road fuel intensity, trips and location patterns, housing, labor and product markets respond to a gas price increase. We find a long-run elasticity of gasoline demand (with congestion endogenous) of ?0.081, keeping constant car prices and the TFI (technological fuel intensity) of car types but allowing consumers to choose from car types. 43% of this long run elasticity is from switching to transit; 15% from trip, car-type and location choice; 38% from price, wage and rent equilibration, and 4% from building stock changes. 79% of the long run elasticity is from changes in car-VMT (the extensive margin) and 21% from savings in gasoline per mile (the intensive margin); with 83% of this intensive margin from changes in congestion and 17% from the substitution in favor of lower TFI. An exogenous trend-line improvement of the TFI of the car-types available for choice raises the long-run response to a percent increase in the gas price from ?0.081 to ?0.251. Thus, only 1/3 of the long-run response to the gas price stems from consumer choices and 2/3 from progress in fuel intensity. From 2000 to 2007, real gas prices rose 53.7%, the average car fuel intensity improved 2.7% and car prices fell 20%. The model predicts that from these changes alone, keeping constant population, income, etc. aggregate gasoline use in this period would have fallen by 5.2%.  相似文献   
7.
Alcorn  Louis G.  Karner  Alex 《Transportation》2021,48(3):1361-1377
Transportation - Informal minibus services dominate public transportation in Lagos, Nigeria. Local, state, and federal government entities in Nigeria have historically only been able to provide...  相似文献   
8.
为什么欧阳若曦被很多人称为波子王呢?这个和他那位富有传奇色彩的父亲有关。想走进这位首位出战FIA世界超级跑车锦标赛的中国人的内心世界吗?请跟我来。汽车生活:最近你的表现非常的良好,在上海会延续这股势头吗?欧阳:说实话,我在上赛场的运气一直不怎么样,我在这里7年跑了12场  相似文献   
9.
"谁会在里面呢?"15年来,每当尼克维阿瑟对人体或者实物进行X线照相时,这个"亘古不变"的问题都会浮现在他的脑海里。令人不解的是,这个对X光射线近乎痴狂的英国人,既不是医生,也不是科学家。人们不禁要问,究竟是什么在他的体内激发出了如此冷门的关趣?事实上,尼克在16岁时就早早辍学,之后为了生计,也只是做了几份  相似文献   
10.
"谁会在里面呢?"15年来,每当尼克维阿瑟对人体或者实物进行X线照相时,这个"亘古不变"的问题都会浮现在他的脑海里。令人不解的是,这个对X光射线近乎痴狂的英国人,既不是医生,也不是科学家。人们不禁要问,究竟是什么在他的体内激发出了如此冷门的关趣?事实上,尼克在16岁时就早早辍学,之后为了生计,也只是做了几份无关痛痒的兼职。也就在那时候,他买了自己的第一个相机,正式开始自己的职业生涯。他起初也只是接一些小打小闹的活。虽然做起来很酷,但是收入也很有限。直到他33岁那年,他才终于找到属于自己的"地盘":X射线。直到现在,尼克仍会把当时看做自己的"命运时刻"。  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