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141.
142.
臭氧和平流层动力学的相互作用 总被引:1,自引:0,他引:1
讨论了给定的南极春季臭氧洞(取自1979—1985年臭氧减少的观测结果)对二维平流层—对流层模式中温度和环流的影响。11月份,南极上空约17km处,温度最多可降低6℃。这种温度变化引起的平均经向环流对臭氧洞起填塞作用,不过,这种影响很小,每年仅产生14DU的变化。观测事实表明,近年来10月份,南半球波活动减弱。为此,我们作了南半球波作用全年都减少一半,并考虑了臭氧洞的数值试验。结果表明,臭氧柱在11月份76°S减少了44DU,在赤道却增加了12DU。 相似文献
143.
144.
Mikls Kedves 《Ore Geology Reviews》1990,5(5-6)
Samples of manganese carbonate and oxide layers from the Úrkút ore deposit were investigated for organic remains, especially for spores and pollen grains. Light (LM), Transmission Electron (TEM), and Scanning Electron Microscopy (SEM) methods were used. LM revealed several new sporomorph taxa; a microstratigraphic standard was established by reconstructing vegetation zones surrounding the sedimentary basin. Index fossils of palynomorphs and the relative abundance of other taxa support a Liassic (Lower Jurassic) age for these layers. TEM data were used to establish: (1) important new understanding about the phylogeny of the pollen-exine ultrastructure and, in particular, the tectate columellar ectexine of the Mesozoic gymnospermous pollen grain, Spheripollenites; and (2) the degree of destruction of the exine ultrastructure helps to reconstruct taphonomical processes during sedimentation and to unravel biopolymer-type molecular structures in the walls of palynomorphs. The SEM method aided in the taxonomy of the microfossils. Combined TEM and SEM methods revealed that submicroscopic surface degradation may be a consequence of bio-degradation during deposition of manganese ore. 相似文献
145.
The three GC coeluting C40 bis-phytanes with head-to-tail, tail-to-tail and head-to-head linkages considered to be archaebacterial markers, have been recognized in petroleum by enhanced mass-fragmentography. Supporting evidence has been obtained by the simultaneous occurrence of two C21–C24 series of isoprenoid and quasi-isoprenoid hydrocarbons that are supposedly formed during the catagenetic degradation of the isomeric C40 isoprenoids. The C21–C24 quasi-isoprenoid hydrocarbons have been identified conclusively for the first time by comparison with authentic standards. 相似文献
146.
Maria Nikkarinen Eeva Kallio Pekka Lestinen Matti Ayrs 《Journal of Geochemical Exploration》1984,21(1-3)
The variation of Cu and Zn contents with grain size was studied in the size fractions: 2000-500 μm, 500-64 μm, 64-2 μm and minus 2 μm. The fixation to different minerals was investigated in the 500-64 μm and minus 64 μm fractions with microscope, microprobe, electron microscope and X-ray diffraction after heavy-liquid separation.The distribution of Cu and Zn between the four size fractions is very similar in all target areas. The contents tend to be highest in the minus 2 μm fraction, and to decrease with increasing grain size except for an increase in the coarsest material. This feature is typical in mineralized areas with till having anomalously high Cu and Zn contents.The anomalous Cu and Zn in the till of Talvivaara are mainly fixed to chalcopyrite and sphalerite, respectively, which indicates that the main part of the material originates from fresh bedrock and that postglacial alterations are slight. In the till of Outokumpu and Maaselkä sulphides are rare. We assume that in Outokumpu the reason for this is the postglacial weathering of sulphides and that in Maaselkä a great deal of till derives from highly weathered, sulphide-poor, preglacial regolith. In both target areas Cu in till seems to fix to limonite and also to clay minerals, particularly in Maaselkä. Zinc seems mainly to be hosted by limonite in Outokumpu. 相似文献
147.
A detailed local structural map of the Mérens Fault zone at Port Vell (Vall Ferrera) reveals that the main fault-related mylonite band splits westwards into a network of mylonite zones. These consist of bands of highly-strained rocks exhibiting tightened folds, transposed foliations and extensive obliteration of pre-existing structures. Evidence of continuity of marble layers across the Port Vell mylonite zone, and structural and metamorphic similarities on both sides of the Port Vell mylonite band, indicate that there is no significant throw across it.The mylonite foliation forms parallel to the axial planes of tight folds in or near the mylonite zone which can be related to more open folds in adjacent areas. The Port Vell mylonite band corresponds to a pinched W-E axial trending late fold.In order to estimate the importance of these results, a review of the controversial geological significance of mylonite belts in the Pyrenees, with special emphasis on the Mérens Fault, introduces the paper. 相似文献
148.
The concept of space is one of the most fundamental of geographical concepts. There is no work in geography that does not certain it. Nevertheless, geography has not as yet formulated an explicit and unambiguous definition of geographical space. This fact has had negative consequences for geographical theory, methodology and application. In the effort of contributing to its elimination we will try to outline the basic connotations of the concept.The concept of geographical space is a relational one. It acquires meaning and sense only when related to other concepts. The concept of space may be conceived as a supplement to things, i.e. substantively conceived objects. Space conceived in this way is the synonym of emptiness. The concept of space may be also conceived in relation ti individual landscape elements as their environments. Space conceived in this way has the character of a field of force. And, finally, space may be conceived also with respect to the totality of landscape elements, i.e. the system expressed by the term synergic. It is only this third variant of space which should be understood as the geographical space in the full menaing of the term. It is only this conception of geographical space as the space filled with qualities in relations and proportions that is considered as one of the basic prerequisites for the formulation of the theory of geography as science capable of prediction and thus also of practical utilization. 相似文献
149.
André Deprit Jesúus Palacián Etienne Deprit 《Celestial Mechanics and Dynamical Astronomy》2001,79(3):157-182
The relegation algorithm extends the method of normalization by Lie transformations. Given a Hamiltonian that is a power series = 0+ 1+ ... of a small parameter , normalization constructs a map which converts the principal part 0into an integral of the transformed system — relegation does the same for an arbitrary function [G]. If the Lie derivative induced by [G] is semi-simple, a double recursion produces the generator of the relegating transformation. The relegation algorithm is illustrated with an elementary example borrowed from galactic dynamics; the exercise serves as a standard against which to test software implementations. Relegation is also applied to the more substantial example of a Keplerian system perturbed by radiation pressure emanating from a rotating source.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
150.
It is presently widely accepted that the solar low p modes show asymmetric profiles when their power spectrum is analysed and that the fact of fitting symmetric profiles yields systematic effects in the obtained frequencies which could affect the results of inversions. In this paper the low p-mode profiles are analysed using wavelets to denoise the power spectra of the modes. This denoising method is applied both to artificial data generated by Kosovichev (the Hare and Hound exercise) and to real data obtained with the GOLF instrument. The asymmetries as well as the frequencies obtained are studied in both cases. The results show that although the obtained p-mode profiles present a slightly negative asymmetry, the use of symmetric profiles to fit the power spectra does not introduce any systematic effect in the obtained frequencies. 相似文献