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Validation of the stochastic distorted-wave Born approximation model with broad bandwidth total target strength measurements of Antarctic krill 总被引:2,自引:0,他引:2
In the computations of SDWBATTS(f) in Figure 4, the scatteredvector was integrated over all orientations in the XY plane,where X is the main axis of the krill, but a factor of 2 was 相似文献
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This document explores the possibilities of multiscale expansions and domain decomposition to solve part of the Couplex 1 exercise. We concentrate on the hydrostatic pressure and show that the slenderness of the domain and the large variations of the Darcy constants allows an analytical approximation which our test reveals to be true to relative errors smaller than 10–3. The numerical tests are done in 2D with freefem+ and in 3D with freefem3D. Some considerations are also given for Iodine transport. 相似文献
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In the caption for Figure 5, it was erroneously stated thatthe TS curves were normalized to L = 31.6 mm. They were normalizedto L = 38.35 相似文献
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Nicolas Mangold Aline Gendrin Stephane LeMouelic Véronique Ansan Yves Langevin Gerhard Neukum 《Icarus》2008,194(2):519-543
Sulfates have been discovered by the OMEGA spectrometer in different locations of the planet Mars. They are strongly correlated to light toned layered deposits in the equatorial regions. West Candor Chasma is the canyon with the thickest stack of layers and one with the largest area covered by sulfates. A detailed study coupling mineralogy derived from OMEGA spectral data and geology derived from HRSC imager and other datasets leads to some straightforward issues. The monohydrated sulfate kieserite is found mainly over heavily eroded scarps of light toned material. It likely corresponds to a mineral present in the initial rock formed either during formation and diagenesis of sediments, or during hydrothermal alteration at depth, because it is typically found on outcrops that are eroded and steep. Polyhydrated sulfates, that match any Ca-, Na-, Fe-, or Mg-sulfates with more than one water molecule, are preferentially present on less eroded and darker outcrops than outcrops of kieserite. These variations can be the result of a diversity in the composition and/or of the rehydration of kieserite on surfaces with longer exposure. The latter possibility of rehydration in the current, or recent, atmosphere suggests the low surface temperatures preserve sulfates from desiccation, and, also can rehydrate part of them. Strong signatures of iron oxides are present on sulfate-rich scarps and at the base of layered deposits scarps. They are correlated with TES gray hematite signature and might correspond to iron oxides present in the rock as sand-size grains, or possibly larger concretions, that are eroded and transported down by gravity at the base of the scarp. Pyroxenes are present mainly on sand dunes in the low lying terrains. Pyroxene is strongly depleted or absent in the layered deposits. When mixed with kieserite, local observations favor a spatial mixing with dunes over layered deposits. Sulfates such as those detected in the studied area require the presence of liquid water to form by precipitation, either in an intermittent lacustrine environment or by hydrothermal fluid circulation. Both possibilities require the presence of sulfur-rich groundwater to explain fluid circulation. The elevation of the uppermost sulfate signatures suggests the presence of aquifers up to 2.5 km above datum, only 1 km below the plateau surface. 相似文献
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Intensity measures for probabilistic assessment of non‐structural components acceleration demand 下载免费PDF全文
Marco De Biasio Stephane Grange Frederic Dufour Frederic Allain Ilie Petre‐Lazar 《地震工程与结构动力学》2015,44(13):2261-2280
A fundamental issue in the framework of seismic probabilistic risk analysis is the choice of ground motion intensity measures (IMs). Based on the floor response spectrum method, the present contribution focuses on the ability of IMs to predict non‐structural components (NSCs) horizontal acceleration demand. A large panel of IMs is examined and a new IM, namely equipment relative average spectral acceleration (E‐ASAR), is proposed for the purpose of NSCs acceleration demand prediction. The IMs efficiency and sufficiency comparisons are based on (i) the use of a large dataset of recorded earthquake ground motions; (ii) numerical analyses performed on three‐dimensional numerical models, representing actual structural wall and frame buildings; and (iii) systematic statistical analysis of the results. From the comparative study, the herein introduced E‐ASAR shows high efficiency with respect to the estimation of maximum floor response spectra ordinates. Such efficiency is particularly remarkable in the case of structural wall buildings. Besides, the sufficiency and the simple formulation allowing the use of existing ground motion prediction models make the E‐ASAR a promising IMs for seismic probabilistic risk assessment. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Nisha Kurian Matthieu Lengaigne Gopalakrishna Venkata Vissa Jerome Vialard Stephane Pous Anne-Charlotte Peter Fabien Durand Shweta Naik 《Ocean Dynamics》2013,63(4):329-346
Active and break phases of the Indian summer monsoon are associated with sea surface temperature (SST) fluctuations at 30–90 days timescale in the Arabian Sea and Bay of Bengal. Mechanisms responsible for basin-scale intraseasonal SST variations have previously been discussed, but the maxima of SST variability are actually located in three specific offshore regions: the South-Eastern Arabian Sea (SEAS), the Southern Tip of India (STI) and the North-Western Bay of Bengal (NWBoB). In the present study, we use an eddy-permitting 0.25° regional ocean model to investigate mechanisms of this offshore intraseasonal SST variability. Modelled climatological mixed layer and upper thermocline depth are in very good agreement with estimates from three repeated expendable bathythermograph transects perpendicular to the Indian Coast. The model intraseasonal forcing and SST variability agree well with observed estimates, although modelled intraseasonal offshore SST amplitude is undere-stimated by 20–30 %. Our analysis reveals that surface heat flux variations drive a large part of the intraseasonal SST variations along the Indian coastline while oceanic processes have contrasted contributions depending of the region considered. In the SEAS, this contribution is very small because intraseasonal wind variations are essentially cross-shore, and thus not associated with significant upwelling intraseasonal fluctuations. In the STI, vertical advection associated with Ekman pumping contributes to ~30 % of the SST fluctuations. In the NWBoB, vertical mixing diminishes the SST variations driven by the atmospheric heat flux perturbations by 40 %. Simple slab ocean model integrations show that the amplitude of these intraseasonal SST signals is not very sensitive to the heat flux dataset used, but more sensitive to mixed layer depth. 相似文献