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   21篇
  免费   0篇
大气科学   1篇
地质学   15篇
海洋学   2篇
天文学   1篇
自然地理   2篇
  2021年   1篇
  2020年   2篇
  2017年   2篇
  2016年   4篇
  2014年   2篇
  2013年   2篇
  2010年   1篇
  2009年   1篇
  2007年   1篇
  2006年   3篇
  2002年   1篇
  1983年   1篇
排序方式: 共有21条查询结果,搜索用时 15 毫秒
1.
A channel account approach is proposed to estimate longitudinal changes in runoff along large river systems. This new method provides a quantitative basis for describing the fluvial transport of suspended particulate material and dissolved substances. This method includes an evaluation of basic elements of water balance in separate sections of the river network and subsequent correction of channel accounting equations for the entire system using a maximum likelihood principle. To calculate water discharges of tributaries that have no hydrological information, structural analysis of river network is performed. This approach provides less error in comparison with traditional methods of estimating lateral inflow. The method is used to trace water discharge with increasing distance along the Lena river basin and to evaluate the contribution of geologically and lithologically uneven sub-basins in water discharge formation during a summer low water period.  相似文献   
2.
3.
4.
A comprehensive lithological–geochemical study of Neopleistocene–Holocene sediments from Russian Arctic showed that these sediments formed in rather similar sedimentation conditions, which were common for polar lithogenesis. This is reflected in the lithology of bottom sediments and their relatively close compositions.  相似文献   
5.
This work presents the results of studying zones bounded by the Archean and Early Proterozoic Taratash block, which breaks the meridional structure of the Urals, pinching its structural zones at the latitude of the town of Miass. The mesostructures of rupture zones, microtextures of tectonites, anisotropy of the magnetic susceptibility, and seismic-wave propagation rate in blastomylonites were studied. The kinematic history of the Taratash block consists of two phases: (1) exhumation in the Middle Riphean under conditions of crustal extension; and (2) the formation of an indenter in the Late Paleozoic under conditions of compression.  相似文献   
6.
Spatiotemporal variability of the internal gravity waves in the Sea of Japan shelf zone (in the Peter the Great Bay) is analyzed basing on the results of the experimental data processing. It is shown that, as for autumn water structure, the tidal internal waves moving towards the coast are transformed due to the non-linear effects and may reach significant amplitudes (of about 10 meters). Such waves are usually referred to as strongly non-linear. The main characteristics of such intense waves were estimated. An example of the disintegration of solitary temperature depression into the package of short-period intense internal waves is given.  相似文献   
7.
Materials of bottom sampling and drilling on Ebelyakh Bay, the Cape Svyatoi Nos area, and southern part of the Dmitry Laptev Strait by researchers from VNIIOkeangeologiya during the past 60 years and data on the geological setting of the Chokhchur–Chokurdakh zone (Ebelyakh Bay included) were also examined. The geology and lithology of Cenozoic sediments in the water area of the bay and adjacent land were scrutinized to elucidate mineral resources in the Earth’s interior in the study area. Analysis of the Upper Jurassic–Holocene summary section shows that terrigenous material was derived from (i) coastal zones composed of granitoid or contact metamorphic rocks, (ii) Quaternary friable sediments of marine terraces and beaches, (iii) submarine rises, and (iv) river discharge. It is shown that cassiterite is associated with the Pliocene–lower Pleistocene Serkino horizon and Holocene sediments. New promising cassiterite areas have been revealed. The results suggest that prospecting for tin placers should be continued at Ebelyakh Bay.  相似文献   
8.
Presented is a detailed characterization of the present state and pollution of soil cover in the influence area of the Dzhidinskii tungsten-molybdenum plant which takes into consideration the spatial geological inhomogeneity and the functional purpose of urban territories. As part of the investigation, we determined the content levels of heavy metals and metalloids in background soils, and the elements which are the main pollutants of urban soils in the zones of different functional purposes, ascertained the degree of technogenic geochemical transformation of soil cover in the city of Zakamensk, and identified the leading soiland landscape-geochemical factors for accumulation of heavy metals and metalloids in the urban topsoil (0?10 cm) horizons. An assessment was also made of the ecological hazard of soil pollution by a set of heavy metals and metalloids in the main functional zones of the city. A soil-geochemical survey was carried out, and the ICP-MS method was used to determine the total content levels of 14 heavy metals and metalloids of hazard classes I?III as well as Be, Sn, Cs and Bi. The elements were determined, which are the main pollutants of the soils in Zakamensk: W, Bi, Cd, Pb and Mo. The study revealed a need to take into account the metallogenic specific character and geological inhomogeneity of the area by using the local coefficients of concentration (EF l ) and dispersal (DF l ) which must be calculated not with respect to the average regional background but from the individual (for each parent material) background value in order to more accurately determine the degree of technogenic geochemical transformation of soils, and the ecological hazard of pollution. It is suggested that the ecological hazard should be assessed on the basis of the Integrated Pollution Index (IPI) which is calculated with respect to the world’s average concentrations of heavy metals and metalloids in soils and takes into account hazard classes of elements.  相似文献   
9.
Doklady Earth Sciences - For the first time, the concentrations of 11 polycyclic aromatic hydrocarbons (PAHs) in urban sealed soils (ekranozems) and asphalt concrete pavement in eastern Moscow have...  相似文献   
10.
Izvestiya, Atmospheric and Oceanic Physics - A way of constructing 3D models of rigid objects from one satellite image is described. It is based on the use of two convolution neural networks which...  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