排序方式： 共有16条查询结果，搜索用时 31 毫秒
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The paper deals with a numerical integrated procedure to calculate the effects of the interaction between sea waves and a tripod-type steel gravity platform. The main aspects to be taken into account for a reliable wave loading analysis of such a new type of platform are emphasized. Among them, the field perturbation effect due to the large bodies presence is analysed. Finally, some principal results in terms of structure global loads obtained by the numerical integrated procedure are presented. 相似文献
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P. Davoodi F. Pozzi S. Oliver M. Polletta A. Afonso-Luis D. Farrah E. Hatziminaoglou G. Rodighiero S. Berta I. Waddington C. Lonsdale M. Rowan-Robinson D. L. Shupe T. Evans F. Fang H. E. Smith J. Surace 《Monthly notices of the Royal Astronomical Society》2006,371(3):1113-1124
We present the rest-frame optical and infrared colours of a complete sample of 1114 z < 0.3 galaxies from the Spitzer Wide-Area Infrared Extragalactic (SWIRE) Legacy Survey and the Sloan Digital Sky Survey (SDSS). We discuss the optical and infrared colours of our sample and analyse in detail the contribution of dusty star-forming galaxies and active galactic nuclei (AGN) to optically selected red sequence galaxies.
We propose that the optical ( g − r ) colour and infrared log( L24 / L 3.6 ) colour of galaxies in our sample are determined primarily by a bulge-to-disc ratio. The ( g − r ) colour is found to be sensitive to the bulge-to-disc ratio for disc-dominated galaxies, whereas the log( L 24 / L 3.6 ) colour is more sensitive for bulge-dominated systems.
We identify ∼18 per cent (195 sources) of our sample as having red optical colours and infrared excess. Typically, the infrared luminosities of these galaxies are found to be at the high end of star-forming galaxies with blue optical colours. Using emission-line diagnostic diagrams, 78 are found to have an AGN contribution and 117 are identified as star-forming systems. The red ( g − r ) colour of the star-forming galaxies could be explained by extinction. However, their high optical luminosities cannot. We conclude that they have a significant bulge component.
The number densities of optically red star-forming galaxies are found to correspond to ∼13 per cent of the total number density of our sample. In addition, these systems contribute ∼13 per cent of the total optical luminosity density, and 28 per cent of the total infrared luminosity density of our SWIRE/SDSS sample. These objects may reduce the need for 'dry mergers'. 相似文献
We propose that the optical ( g − r ) colour and infrared log( L
We identify ∼18 per cent (195 sources) of our sample as having red optical colours and infrared excess. Typically, the infrared luminosities of these galaxies are found to be at the high end of star-forming galaxies with blue optical colours. Using emission-line diagnostic diagrams, 78 are found to have an AGN contribution and 117 are identified as star-forming systems. The red ( g − r ) colour of the star-forming galaxies could be explained by extinction. However, their high optical luminosities cannot. We conclude that they have a significant bulge component.
The number densities of optically red star-forming galaxies are found to correspond to ∼13 per cent of the total number density of our sample. In addition, these systems contribute ∼13 per cent of the total optical luminosity density, and 28 per cent of the total infrared luminosity density of our SWIRE/SDSS sample. These objects may reduce the need for 'dry mergers'. 相似文献
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Berta Biescas François Dufour Glória Furdada Giorgi Khazaradze Emma Suriñach 《Surveys in Geophysics》2003,24(5-6):447-464
Seismic signals generated by avalanches have been recorded by theavalanche team of the Universitat de Barcelona at theVallée de la Sionne experimental site (Switzerland) since 1998. During these years avalanches of varying size and flowwere recorded by two sensors located at different positions.In the present paper we show the general features of the running spectra of the seismicsignals for the different type of recorded avalanches. Using this method we are able not only to detect avalanches with low amplitude signals but also to distinguishbetween avalanches and other seismic sources (i.e., local earthquakes) which have thesame frequency content but a different frequency evolution. 相似文献
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Seismic attenuation of coda waves in the eastern region of Cuba 总被引：1，自引：0，他引：1
Cuba's seismic attenuation had never been studied in detail. In this paper we present the results of the research on the seismic attenuation of Cuba's eastern zone based upon the information collected by the seismological Cuban network from 1998 to 2003. 581 earthquakes were selected from the Cuban catalogue to make this study. All of them, recorded by at least three seismic stations, had their epicenters located in the eastern Cuban region (19.3–22 N, 79–73 W), epicentral distances between 15 km and 213 km, their coda duration magnitudes ranging from 2 and 4.1 and their focal depths reaching up to 30 km. The seismic wave attenuation was studied using coda waves. The single scattering method proposed by Sato in 1977 was applied, the attenuation and frequency dependency for different paths and the correlation of the results with the geotectonics of the region are presented in this paper.The mean Qc value calculated was Qc = (64 ± 2)f0.84 ± 0.01. The relatively low Q0 and the high frequency dependency agree with the values of a region characterized by a high tectonic activity. The Qc values of seven subregions of eastern Cuba were calculated and correlated with the geology and tectonics of the area. 相似文献
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Abstract In this paper we process diachronic SPOT satellite images acquired with different viewing angles in order to assess the aerosol optical thickness (AOT) spatial distribution over Brescia. This urban area, located in Northern Italy, is subject to frequent visibility‐reducing smog episodes. AOT was calculated by using the Differential Textural Analysis (DTA) code on a satellite data series consisting by one pollution‐free and various pollution‐loaded SPOT images. The resulting maps showed the horizontal distribution of AOT with a resolution of 500 metres. These maps can be readily integrated with the results obtained by mesoscale modelling, ground measurements, and respond to local scale application requirements. Satellite AOT retrieval compared successfully with available AOT ground‐based measurements and with pollution measurements in the ambient air. In this study the use of diachronic multiangle SPOT imagery allowed us to analyse the effect of the viewing angle variation on AOT retrieval accuracy based on the contrast reduction method. 相似文献
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Michael Rowan-Robinson Tom Babbedge Seb Oliver Markos Trichas Stefano Berta Carol Lonsdale Gene Smith David Shupe Jason Surace Stephane Arnouts Olivier Ilbert Olivier Le Févre Alejandro Afonso-Luis Ismael Perez-Fournon Evanthia Hatziminaoglou Mari Polletta Duncan Farrah Mattia Vaccari 《Monthly notices of the Royal Astronomical Society》2008,386(2):697-714
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