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   30篇
  免费   0篇
测绘学   1篇
地球物理   4篇
地质学   9篇
海洋学   5篇
天文学   9篇
自然地理   2篇
  2016年   3篇
  2015年   1篇
  2014年   3篇
  2013年   1篇
  2010年   2篇
  2009年   2篇
  2008年   1篇
  2007年   2篇
  2006年   1篇
  2005年   1篇
  2004年   3篇
  2003年   2篇
  2002年   1篇
  1999年   1篇
  1997年   1篇
  1996年   1篇
  1995年   1篇
  1983年   1篇
  1981年   1篇
  1976年   1篇
排序方式: 共有30条查询结果,搜索用时 15 毫秒
1.
The paper deals with a numerical integrated procedure to calculate the effects of the interaction between sea waves and a tripod-type steel gravity platform. The main aspects to be taken into account for a reliable wave loading analysis of such a new type of platform are emphasized. Among them, the field perturbation effect due to the large bodies presence is analysed. Finally, some principal results in terms of structure global loads obtained by the numerical integrated procedure are presented.  相似文献   
2.
3.
4.
长江三角洲南部“大城市圈振兴”理论的质疑   总被引:3,自引:0,他引:3  
Mart.  AM 《地理学报》1996,51(3):272-282
工业发展和城市化的传统理论,对亚洲的某些具有较高生产力水平,且还在发展中的“大城市圈”不能充分地解释,本文对长江三角洲南部空间经济转为的“大城市圈振兴”理论进行了批判地评论,根据最新的现场调查结果,从根本上对“转为过程”的假说提出质疑,并且提出了更适当的的区域发展战略,此外还证明,关于亚洲大城市带的一般结论,必须建立在对地方性经济变革认识的基础之上。  相似文献   
5.
We present the rest-frame optical and infrared colours of a complete sample of  1114 z < 0.3  galaxies from the Spitzer Wide-Area Infrared Extragalactic (SWIRE) Legacy Survey and the Sloan Digital Sky Survey (SDSS). We discuss the optical and infrared colours of our sample and analyse in detail the contribution of dusty star-forming galaxies and active galactic nuclei (AGN) to optically selected red sequence galaxies.
We propose that the optical  ( g − r )  colour and infrared  log( L 24/ L 3.6)  colour of galaxies in our sample are determined primarily by a bulge-to-disc ratio. The  ( g − r )  colour is found to be sensitive to the bulge-to-disc ratio for disc-dominated galaxies, whereas the  log( L 24/ L 3.6)  colour is more sensitive for bulge-dominated systems.
We identify ∼18 per cent (195 sources) of our sample as having red optical colours and infrared excess. Typically, the infrared luminosities of these galaxies are found to be at the high end of star-forming galaxies with blue optical colours. Using emission-line diagnostic diagrams, 78 are found to have an AGN contribution and 117 are identified as star-forming systems. The red  ( g − r )  colour of the star-forming galaxies could be explained by extinction. However, their high optical luminosities cannot. We conclude that they have a significant bulge component.
The number densities of optically red star-forming galaxies are found to correspond to ∼13 per cent of the total number density of our sample. In addition, these systems contribute ∼13 per cent of the total optical luminosity density, and 28 per cent of the total infrared luminosity density of our SWIRE/SDSS sample. These objects may reduce the need for 'dry mergers'.  相似文献   
6.
The “TNOs are Cool!: A survey of the trans-Neptunian region” is a Herschel Open Time Key Program that aims to characterize planetary bodies at the outskirts of the Solar System using PACS and SPIRE data, mostly taken as scan-maps. In this paper we summarize our PACS data reduction scheme that uses a modified version of the standard pipeline for basic data reduction, optimized for faint, moving targets. Due to the low flux density of our targets the observations are confusion noise limited or at least often affected by bright nearby background sources at 100 and 160 \(\mu \) m. To overcome these problems we developed techniques to characterize and eliminate the background at the positions of our targets and a background matching technique to compensate for pointing errors. We derive a variety of maps as science data products that are used depending on the source flux and background levels and the scientific purpose. Our techniques are also applicable to a wealth of other Herschel solar system photometric observations, e.g. comets and near-Earth asteroids. The principles of our observing strategies and reduction techniques for moving targets will also be applicable for similar surveys of future infrared space projects.  相似文献   
7.
The boloSource() algorithm is a tool to separate the signal of compact sources from that of the diffuse background in the timeline of far-infrared measurements performed by the PACS camera of the Herschel Space Observatory. An important characteristic and quality indicator of this method is that how well it can reproduce the flux of faint standard stars which have reliable flux estimates. For this propose we selected a few calibrator targets and constructed light curves by extracting point source flux for each repetition of the measurements independently using standard aperture photometry methods. These were compared with the light curves obtained using the boloSource() method on the same dataset. The results indicate that boloSource() provides a similar level of photometric accuracy and reproducibility as the usual flux extraction and photometry methods. This new technique will be developed further and also tested against other methods in more complex fields with the goal to make it usable for large-scale studies in the future.  相似文献   
8.
Marton  A 《地理科学》1997,17(1):8-17
在东北亚区域发展方向论述了经济快速增长,资源转移和区域贸易格局的特点,随着后分析了图们江地区开发的国际环境以及图们江发展计划,指出图们江开发的几种可能选择和图们江与东北亚经济协作前景,特别提出加强国与国之间的贸易具有重要意义。  相似文献   
9.
Australia’s Integrated Marine Observing System (IMOS, imos.org.au) is research infrastructure to establish an enduring observing program for Australian oceanic waters and shelf seas. The observations cover physical, biological, and chemical variables to address themes of multi-decadal ocean change, climate variability and weather extremes, boundary currents and inter-basin flows, continental shelf processes and ecosystem responses.IMOS observations are collected by national facilities based on various platform types and operated by partner institutions around the country. In this paper we describe the infrastructure and workflows developed to manage and distribute the data to the public. We highlight the existing standards and open-source software we have adopted, and the contributions we have made. To demonstrate the value of this infrastructure we provide some illustrations of use and uptake.All IMOS data are freely and openly available to the public via the Ocean Portal (https://imos.aodn.org.au). All IMOS-developed software is open-source and accessible at https://github.com/aodn.  相似文献   
10.
From 1955 to 1985 an intensive hydrogeological survey has been carried out in Slovakia, in order to ascertain the conditions of forming mineral and geothermal waters in various geological structures and to find new sources of the afore-mentioned waters. The survey helped to clarify the laws of their distribution and evaluate the quantitative and qualitative properties of water developing on the basis of geologic-tectonic conditions and physical-geographic terms of the given territory. The Slovakian territory belongs to the Carpathian geological system. Five separate geological units having a different hydrologic characteristic, quality and water yield of reserves and resources form this geological system. A great number of mineral and thermal springs in Slovakia displaying different quantities and quality, provide numerous possibilities of their practical utilization.  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