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131.
132.
Gilbert F. White 《The Professional geographer》1972,24(4):302-309
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The Resolving Power of Gross Earth Data 总被引:22,自引:0,他引:22
A gross Earth datum is a single measurable number describing some property of the whole Earth, such as mass, moment of interia, or the frequency of oscillation of some identified elastic-gravitational normal mode. We show how to determine whether a given finite set of gross Earth data can be used to specify an Earth structure uniquely except for fine-scale detail; and how to determine the shortest length scale which the given data can resolve at any particular depth. We apply the general theory to the linear problem of finding the depth-variation of a frequency-independent local Q from the observed quality factors Q of a finite number of normal modes. We also apply the theory to the non-linear problem of finding density vs depth from the total mass, moment, and normal-mode frequencies, in case the compressional and shear velocities are known. 相似文献
136.
G. Fielder 《Planetary and Space Science》1962,9(12):929-938
Measurements of shadows cast by the lunar Straight Wall are corrected, where possible, for systematic errors and relative altitudes are obtained. All known sources of error are taken into account to compute the most probable error in a result, which is commonly ±10 per cent of the altitude. The results from the photographic method are compared with visual estimates. It is shown that the top of the Straight Wall is level to within ±100 m. For several different shadow lengths, the greatest relative altitude is near to the centre of the Wall, and is of the order of 400 m. The mean relative altitude of the Straight Wall is 300 m for short shadows and 380 m for long shadows. 相似文献
137.
Gilbert Mille Jan Yu Chen Henri Dou Edgar Azoulay Maryse Colin Jean-Claude Bertrand 《Marine environmental research》1985,17(1):65-80
Coastal Mediterranean sediments highly polluted by refinery effluents have been studied for their hydrocarbon content and bacterial activity. The study has taken into account both the distance from the refinery and depth of sampling. Very high hydrocarbon concentrations have been found (1–250 g/kg dry sediment). Micro-organisms in the sediments have a high bacterial activity and a good correlation exists between hydrocarbon concentrations and bacteria able to use these substrates as a carbon and energy source. 相似文献
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G. D. Gilbert L. S. Dolin I. M. Levin A. G. Luchinin S. Stewart 《Izvestiya Atmospheric and Oceanic Physics》2006,42(1):115-123
Statistical models of the useful and background signals forming an image of the sea bottom observed through a rough sea surface are constructed. The methods for estimating the signal-to-noise ratio in the image of the bottom with the test distribution of the reflectance are described. The dependence of the signal-to-noise ratio on observational conditions, in particular, on the mutual orientation of the directions of sighting, wind, and solar vertical, is analyzed. Recommendations on the choice of optimal conditions for bottom observations from airborne carriers are given. 相似文献
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