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41.
概述辽、金、元三代有关测绘的管理和机构,职官设置,各类测绘状况及成果,着重介绍了元代的测绘技术,发明创造及著述。 相似文献
42.
A classification system for the assessment of slope stability of terrains along highway routes in Jordan 总被引:2,自引:0,他引:2
The establishment of comprehensive development plans, in general, and the proper selection of highway routes, in particular,
require an assessment of landslides or instability hazards in the project sites. The frequent landslides that occurred along
the routes of major highways in Jordan, and particularly along the Amman-Na'ur-Dead Sea highway and Irbid-Jerash-Amman highway,
have substantially increased the cost of construction and caused a considerable delay in the completion of work. The study
of many landslides that occurred in the last 25 years along the highway routes and in the sites of some major civil engineering
projects in Jordan has led to the recognition of major factors that affect the stability of slopes, and thus the safety and
economics of these projects. The geological formation, structural features, topographic characteristics, geometry, and climatic
conditions were adopted as the basis for the classification of terrains in terms of their stability. Each factor has been
assigned a rating to indicate its relative contribution to the overall stability according to engineering judgment and past
experience. The areas have been classified into 5 groups according to their total stability rate. The simplicity, comprehensiveness,
and accuracy are the main characteristics of the proposed classification. Its significance stems from its helpfulness as a
guide to the geotechnical and highway engineers in assessing the overall stability of the alternative routes of proposed highway
projects.
Received: 3 December 1996 · Accepted: 29 April 1997 相似文献
43.
Z. Kaymaz 《Annales Geophysicae》1998,16(4):376-387
This study presents cross-sectional vector maps of the magnetic field derived from IMP 8 magnetometer in the magnetosheath at 30 Re behind the Earth. In addition the vector patterns of the magnetosheath field for northward, southward, and east-west interplanetary magnetic field (IMF) directions are qualitatively compared with those obtained from the Spreiter-Stahara gas dynamic (GD) and Fedder-Lyon magnetohydrodynamic models (MHD). The main purpose is to display the cross-sectional differences in relation to the dayside merging with different IMF directions, allowing the reader to make direct visual comparisons of the vector patterns. It is seen that for east-west IMF directions, the data-based and MHD-based patterns differ noticeably in a similar way from the GD model, presumably reflecting the influence of dayside magnetic merging of the Earths magnetic field with the y-component of the interplanetary magnetic field. All three northward IMF cross sections show comparable field draping patterns as expected for a closed magnetosphere. For southward IMF case, on the other hand, differences between the three cross-sectional patterns are greater as seen in the field vector sizes and directions, especially closer to the magnetopause where more disturbed magneto-spheric conditions are known to be exist. The data comparisons with the MHD and GD models show that the differences result from the magnetic field-flow coupling and that the effects of dayside reconnection are present in IMP 8 magnetic field measurements. 相似文献
44.
《The Professional geographer》1990,42(3):386-390
AMOS—Analysis of MOment Structures . James Arbuckle CLIMATEDATA–Summary of the Day . (Version 1.10). HYDRODATA–U.S.G.S. Daily Values (Version 2.0). The MAP SETS (includes EUROPEAN MAPSET, US MAPSET and WORLD MAPSET). James Taylor 相似文献
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??2012??1???????????????????г??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????к?????????????????????????????????--?????????????????????????????? 相似文献
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