Study of clusters of galaxies by correlation analysis     

José M. Solanes  Manuel Sanromà  Eduard Salvador-Solé 《Astrophysics and Space Science》1990,171(1-2):9-12

We present preliminary results of the application to real data of a new method for studying the structure of groups and clusters of galaxies. The new method is able to produce reliable results for structures with a small number of galaxies. The 6 clusters whose number density and velocity dispersion profiles are determined, could have hardly been studied with classical methods. These new results are particularly significant, especially in what concerns the velocity dispersion profile, since little is known so far on its characteristics.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

A continuous record of Holocene eolian activity in West Greenland     

Nico W. Willemse  Eduard A. Koster  Babette Hoogakker  Frank G. M. van Tatenhove   《Quaternary Research》2003,59(3):322-334

Eolian landforms are widespread alongside proglacial valley-sandurs in West Greenland and comprise low-relief sand sheets, climbing dunes, and upland loess. Sedimentary facies mainly reflect distance to outwash-source zones and the influence of vegetation cover. The sediments show stratification types typical for poorly to moderately vegetated sand-sheets, alternately laminated silt/peat sequences, and unstratified loess. Twenty-five accelerator mass spectrometry ¹⁴C dates provide the basis for the chronostratigraphy of the inland eolian deposits. ¹⁴C dates from interstratified sand-sheets suggest that the bulk of eolian sands were deposited prior to 3400 cal yr B.P. and after 550 cal yr B.P. This two-phase formation for the inland dunes most likely reflects local changes in proglacial floodplain development and meltwater rerouting associated with a significant recession of the Greenland ice sheet during the mid Holocene climate optimum. Subsequent floodplain regeneration and renewed sand-sheet formation after 550 cal yr B.P. followed when the ice margin readvanced to its present position. In contrast, atmospheric deposition of regionally derived silt in upland peat mires has been continuous since at least 4750 cal yr B.P. Silt influx data demonstrate a strongly episodic history of the intensity of eolian activity over the past five millennia, which tentatively reflects alternating periods of (winter) aridity associated with the variable incursion of maritime air masses over the interior ice-free areas of West Greenland.  相似文献   

Analysis of body supercavitation in shallow water   总被引：1，自引：0，他引：1  

Eduard Amromin   《Ocean Engineering》2007,34(11-12):1602-1606

Motion of a cavitating body in shallow waters undergoes a blockage effect. There are influences of the rigid boundary (the sea bottom) and the free boundary (sea surface) in shallow waters. As shown by computation carried out with the ideal fluid theory, the combination of these influences leads to an increase of cavitation number for a cavity of a fixed length and to 3D deformations of the cavity cross-sections, with a swelling of the down cavity part.  相似文献   

Two-range scaling for tip vortex cavitation inception     

Eduard Amromin 《Ocean Engineering》2006,33(3-4):530-534

The suggested scaling concept for cavitation inception index takes into account boundary layer separation caused by tip vortices, as well as difference in dependencies of boundary layer thickness on Reynolds number for laminar and turbulent boundary layer. Provided asymptotic analysis gives two scaling laws with different values of power for high and low Reynolds numbers. Deduced values correspond well to known experimental data.  相似文献   

Formulation of the multiple anisotropic scattering process in two dimensions for anisotropic source radiation     

Eduard Carcolé  Arantza Ugalde 《Geophysical Journal International》2008,174(3):1037-1051

The radiative transfer theory (RTT) describes the energy transport through a random heterogeneous medium, neglecting phase information. It provides an adequate framework for modelling high-frequency seismogram envelopes. For isotropic scattering and sources, the radiative transfer equation (RTE) has been formulated analytically and numerically simulated using Monte Carlo methods for acoustic and elastic media. Here, we derive an exact analytical solution of the RTE in 2-D space for the acoustic case, including anisotropic scattering for a anisotropic point-like impulsive source. For this purpose, we generalize the path integral method, which has been used before in the isotropic case, to take into account the anisotropy of both the source radiation pattern and scattering processes, simultaneously. Then we obtain a general solution, which is written in a closed form in the Fourier space. To illustrate the theoretical results, we compute the full space and time evolution of the specific intensity for an arbitrary case. We also compare the time traces computed from our general solution with cases in which the source and/or the scattering process are isotropic. The importance of taking into account both anisotropies simultaneously becomes obvious in our examples. We also show that at long lapse time, our example approaches the solution of the diffusion equation.  相似文献   

蒙古中部地区植被覆盖衰退问题案例研究（英文）     

Bair Z. TSYDYPOV  Endon Zh. GARMAEV  Arnold K. TULOKHONOV  Eduard A. BATOTSYRENOV  Alexander A. AYURZHANAEV  Zhargalma B. ALYMBAEVA  Ts. CHIMEDDORJ 《资源与生态学报(英文版)》2015,6(2):73-78

本文选择蒙古中部地区的两个模型多边形对植被多样性进行调查研究。它们都位于干旱、半干旱少雨地区。基于Landsat TM影像,本文研究了多边形区域的NDVI随时间变化的多时相NDVI值制图,得到所选择的具备不同值NDVI区域的全尺度景观特征。这一特征在对耐旱环境组的植被分析中得到了证实。该过程中将近整个实验多边形区域的植被偏离得到了追踪。NDVI的时间分布分析呈现出数值的降低,这说明了在戈壁,稀疏植被存在耐旱趋势。在半干旱气候区域中偏离植被趋势与牧草地的重载负直接相关。  相似文献   

Scale radii and aggregation histories of dark haloes     

Eduard Salvador-Solé  Alberto Manrique  José María Solanes 《Monthly notices of the Royal Astronomical Society》2005,358(3):901-912

  相似文献   

Reduction of the general fracture compliance matrix Z to only five independent elements     

Eduard Berg  Julie A. Hood  Gerard J. Fryer 《Geophysical Journal International》1991,107(3):703-707

  相似文献   

Model orbits of asteroid 3040 Kozai     

Nina A. Solovaya  Eduard M. Pittich 《Earth, Moon, and Planets》1995,68(1-3):523-528

The orbital evolutions of the asteroid 3040 Kozai and model asteroids with similar orbits have been investigated. Their osculating orbits for an epoch 1991 December 10 were numerically integrated forward within the interval of 20,000 years, using a dynamical model of the solar system consisting of all inner planets, Jupiter, and Saturn.The orbit of the asteroid Kozai is stable. Its motion is affected only by long-period perturbations of planets. With change of the argument of perihelion of the asteroid Kozai, the evolution of the model asteroid orbits changes essentially, too. The model orbits with the argument of perihelion changed by the order of 10% show that asteroids with such orbital parameters may approach the Earth orbit, while asteroids with larger changes may even cross it, at least after 10,000 years. Long-term orbital evolution of asteroids with these orbital parameters is very sensitive on their angular elements.  相似文献   

Reply to Comment by W. Kurz on “Tectonic map and overall architecture of the Alpine orogen”     

Stefan M. Schmid  Bernhard Fügenschuh  Eduard Kissling  Ralf Schuster 《Eclogae Geologicae Helvetiae》2005,98(1):99-101

  相似文献