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141.
142.
A euphotic zone seems to exist at about 1 cm subsurface in the Martian epilith. At this depth visible light is still intense enough to be utilized by conceivable photosynthetic organisms; but the germicidal ultraviolet intensities at the Martian surface have been reduced to values manageable by terrestrial life. Such euphotic zone organisms would experience moderately high Martian temperatures at equatorial latitudes and can be dispersed readily during global dust stroms. During such storms the Martian euphotic zone may reach the surface. The aerosol content of the Martian atmosphere can be monitored by multiband single line scans of the sun at large zenith angles by the Viking lander camera; and the postulated euphotic zone organisms can be searched for with the Viking lander sample arm and biology experiments. 相似文献
143.
144.
Carl A. Rouse 《Solar physics》1986,106(2):205-216
The high-Z core (HZC) model of the Sun, supported in Rouse (1985) by superior agreements of nonradial g-mode periods of oscillation with long period observations, is used to calculate frequencies of oscillation in the five-minute band (5MB). Allowing for the fact that the present HZC model profile does not include an upper photosphere and self-consistent chromosphere, the HZC model of the Sun is also supported by the very good agreements of the 5MB nonradial frequencies of oscillation with observations for HZC l degrees 0 to 19 and orders n 20, and the good agreement of the HZC purely radial frequencies of oscillation with about the same n-orders with observations previously identified as l = 0 oscillations. Two important aspects of these agreements are (1) the nonradial frequencies were calculated with the equations that neglect the gravitational perturbation (the Cowling approximation), and (2) the radial frequencies were calculated with the equation that includes the gravitational perturbation. The present agreements suggest that for solar-type stars, the gravitational perturbation may not affect the nonradial p-modes of oscillation as much as it affects the radial modes and the nonradial g-modes. More research will be performed. 相似文献
145.
Carl Sagan 《Icarus》1973,20(4):513-514
Some 109 to 1010 metric tons of low albedo material, transported during the course of a century to the permanent Martian polar caps, may be capable of rapidly transforming Mars to much more Earth-like conditions. Alternatively the introduction to Mars of a dark plant which grows on the polar snows might accomplish the same objective. Fortunately neither program is a practical engineering venture for the near future. 相似文献
146.
Carl Troll 《International Journal of Earth Sciences》1944,34(7-8):545-694
Ohne Zusammenfassung 相似文献
147.
Carl T. F. Ross Andrew P. F. Little Leonidas Chasapides Jeff Banks Daniele Attanasio 《Ocean Engineering》2004,31(2):239-252
The paper reports on the buckling of three ring-stiffened prolate domes under external hydrostatic pressure. The study was partly theoretical and partly experimental, where in the case of the latter, the finite element was used. Comparison between experiment and theory was good. The effect of ring stiffening the domes was to increase their buckling resistances by factors varying from 4.43 to 5.72. 相似文献
148.
After reviewing the inverse method, we apply it to deducing the general circulation of the North Atlantic ocean. We argue that the method is purely classical in nature, being nothing more than a mathematical statement of the principles upon which nearly all previous circulation schemes have been based. The ‘smoothed’ solution is shown to represent the components of the flow field that are determinable independently of the initial reference level. We then produce two circulation schemes based upon two different initial reference levels — 2000 decibars and the bottom — called North Atlantic-1A and North Atlantic-1B respectively. The models share many features in common and are strikingly similar to several previous schemes, most notably those of Jacobsen and Defant in the region west of Bermuda. No simple level-of-no-motion emerges in the flow fields; rather the velocity sections exhibit a complex cellular structure. Zonally integrated meridional cells of models and of the uniquely determined components are very similar, showing a poleward movement of warm saline water compensated at depth by a return flow of cold, fresher water. The magnitudes of the implied polar sea overflows and the heat fluxes are in good agreement with previous estimates. Finally, it is argued that neither these model circulations nor any other circulation pattern based upon the existing data can be regarded as actually representing the true time average ocean circulation because the data are aliased in time; the frequency/wavenumber spectrum of the ocean is inadequately known to determine the resulting errors. 相似文献
149.
The paper presents a theoretical and an experimental investigation into the free vibration of a large ring-stiffened prolate dome in air and under external water pressure.The theoretical investigation was via the finite element method where a solid fluid mesh with an isoparametric cross-section was used to model the water surrounding the dome, and a truncated conical shell and ring stiffener were used to model the structure. Good agreement was found between theory and experiment. Both the theory and the experiment found that as the external water pressure was increased the resonant frequencies decreased. 相似文献
150.
Kell Laurence T.; Pilling Graham M.; O'Brien Carl M. 《ICES Journal of Marine Science》2005,62(7):1483-1491