排序方式: 共有18条查询结果,搜索用时 15 毫秒
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F. Bocchio 《Geophysical Journal International》1983,72(2):453-459
Summary. It is shown that disturbing masses can be found which can give locally rise in the external gravity field of a spherically symmetric earth to singularities both in geodetic and in gravity space coordinates; in this connection the concept of absolute geodetic singularities is introduced. It is also shown that the previous results hold independently of the mass of the disturbing body and for densities of the disturbing mass which can be lower than the mean Earth density. The connection between the geodetic singularity problem and the study and design of gravity gradient compensators for orbital experiments is put into light. 相似文献
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Fe (136,900 ppm)- and Ti (28,540 ppm)-rich eclogites contained in the Voltri serpentinites show contents of metallic trace elements different from those of other eclogites described so far, both those of ophiolitic type and those included in ultramafic rocks. The Voltri eclogites are enriched in Mn (1,894 ppm), V (610 ppm), and Co (75 ppm) and depleted in Cr (110 ppm), Ni (56 ppm), and Zr (46 ppm) in comparison with other occurrences. The analyzed samples are: twelve flaser-eclogites, four fine-grained bimineralic eclogites and three eclogites showing an advanced degree of retrometamorphism toward greenschist facies. The given average values (in ppm) are based on nineteen analyzed samples. This trace-element content is believed to reflect the highly fractionated tholeiitic character of the eclogites and suggests that the Voltri rocks originated from the isochemical metamorphism of ferrogabbros which were probably intruded into the serpentinized lherzolites of a mid-oceanic ridge at the time of the opening of the Pennidic trough. 相似文献
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F. Bocchio 《Geophysical Journal International》1985,81(2):463-467
Summary. In view of present attempts to build orbiting gravity gradiometers with an accuracy of about 10−4 E, perturbing gravitational gradients arising from tide-generating bodies and from rotational deformations induced by polar motion are evaluated. 相似文献
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F. Bocchio 《Geophysical Journal International》1979,57(2):343-351
Summary. The first-order theory of three-dimensional representations of the actual gravity field of the Earth on the normal field given by Bocchio has been applied to the class of isoparametric-and of isozenithal-type mappings. The resulting linear and angular deformations together with the expressions for the gravity anomalies and disturbances have been compared and discussed and some invariant relations have been put into evidence. 相似文献
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F. Bocchio 《Geophysical Journal International》1982,68(3):643-652
Summary. An inverse geodetic singularity problem is considered for a non-homogeneous spherical planet. The singularity condition is expressed in terms of the density distribution and of the geometrical parameters of the configuration; the condition for the density distribution is deduced which gives rise to singularities of parabolic type in the external gravity field of the planet. The structure of the gravity field in the neighbourhood of the singularities is investigated in detail together with the behaviour of the gradients of the disturbances in the geodetic coordinates. 相似文献
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Marcio M. Lobão Jari N. Cardoso Marcio R. Mello Paul W. Brooks Claudio C. Lopes Rosangela S.C. Lopes 《Marine pollution bulletin》2010,60(12):2263-2274
The current work aimed to identify the source of an oil spill off the coast of Maranhão, Brazil, in September 2005 and effect a preliminary geochemical survey of this environment. A combination of bulk analytical parameters, such as carbon isotope (δ13C) and Ni/V ratios, and conventional fingerprinting methods (High Resolution Gas Chromatography and Mass Spectrometry) were used. The use of bulk methods greatly speeded source identification for this relatively unaltered spill: identification of the likely source was possible at this stage. Subsequent fingerprinting of biomarker distributions supported source assignment, pointing to a non-Brazilian oil. Steranes proved the most useful biomarkers for sample correlation in this work. Distribution patterns of environmentally more resilient compound types, such as certain aromatic structures, proved inconclusive for correlation, probably in view of their presence in the background. 相似文献
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