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121.
Tobias Goerdt Ben Moore J. I. Read Joachim Stadel Marcel Zemp 《Monthly notices of the Royal Astronomical Society》2006,368(3):1073-1077
The dark matter dominated Fornax dwarf spheroidal has five globular clusters orbiting at ∼1 kpc from its centre. In a cuspy cold dark matter halo the globulars would sink to the centre from their current positions within a few Gyr, presenting a puzzle as to why they survive undigested at the present epoch. We show that a solution to this timing problem is to adopt a cored dark matter halo. We use numerical simulations and analytic calculations to show that, under these conditions, the sinking time becomes many Hubble times; the globulars effectively stall at the dark matter core radius. We conclude that the Fornax dwarf spheroidal has a shallow inner density profile with a core radius constrained by the observed positions of its globular clusters. If the phase space density of the core is primordial then it implies a warm dark matter particle and gives an upper limit to its mass of ∼0.5 keV, consistent with that required to significantly alleviate the substructure problem. 相似文献
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Landslide susceptibility analysis based on ArcGIS and Artificial Neural Network for a large catchment in Three Gorges region,China 总被引:1,自引:0,他引:1
Renneng Bi Markus Schleier Joachim Rohn Dominik Ehret Wei Xiang 《Environmental Earth Sciences》2014,72(6):1925-1938
A landslide susceptibility map is very important and necessary to efficiently prevent and mitigate the losses brought by natural hazard for a large area. For the purpose of landslide susceptibility analysis for the whole Xiangxi catchment (3,209 km2), Artificial Neural Network (ANN) analysis was applied as the main method. The whole catchment was divided into two parts: the training area and the implementation area. The backwater area (559 km2) of Xiangxi catchment was used as the training area for the ANN method. In the training area the correlations between the landslide distribution and its causative factors, which includes lithology, slope angle, slope curvature and river network, have been analyzed based on the geological map and digital elevation model (DEM). The back-propagation training algorithm in ANN was selected to train the sample data from the training area, which were composed of input data (causative factors) and target output data (landslide occurrence), in order to find the correlations between them. Based on these correlations and input data in the implementation area (causative factors), the network output data were obtained for the implementation area. In the end, a map of landslide susceptibility, which was established by network output data, was presented for Xiangxi catchment. ArcGIS was applied to extract and quantify input information from a DEM for susceptibility analysis and also to present the result visually. As a result, a landslide susceptibility map, in which 70 % of all landslides are rightly classified in the training area (backwater area), was created for Xiangxi catchment. 相似文献
124.
Ocean Dynamics - Salinity observations in the Vietnamese upwelling area in June 2016 indicated a significant increase in the salinity of the maximum salinity water (MSW). The source of MSW inflow... 相似文献
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Guanche García Yanira Shadaydeh Maha Mahecha Miguel Denzler Joachim 《Natural Hazards》2019,98(3):849-867
Natural Hazards - Detecting abnormal events within time series is crucial for analyzing and understanding the dynamics of the system in many research areas. In this paper, we propose a methodology... 相似文献
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Joachim Heimberger Michael Soffel Hanns Ruder 《Celestial Mechanics and Dynamical Astronomy》1989,47(2):205-217
The motion of artificial satellites in the gravitational field of an oblate body is discussed in the post — Newtonian framework using the technique of canonical Lie transformations. Two Lie transformations are used to derive explicit results for the longperiodic and secular perturbations for satellite orbits in the Einstein case. 相似文献
130.
Klaus Peter Jochum Steven A. Wilson Wafa Abouchami Marghaleray Amini Jérome Chmeleff Anton Eisenhauer Ernst Hegner Linda M. Iaccheri Bruno Kieffer Joachim Krause William F. McDonough Regina Mertz‐Kraus Ingrid Raczek Roberta L. Rudnick Denis Scholz Grit Steinhoefel Brigitte Stoll Andreas Stracke Sonia Tonarini Dominique Weis Ulrike Weis Jon D. Woodhead 《Geostandards and Geoanalytical Research》2011,35(2):193-226
This paper contains the results of an extensive isotopic study of United States Geological Survey GSD‐1G and MPI‐DING reference glasses. Thirteen different laboratories were involved using high‐precision bulk (TIMS, MC‐ICP‐MS) and microanalytical (LA‐MC‐ICP‐MS, LA‐ICP‐MS) techniques. Detailed studies were performed to demonstrate the large‐scale and small‐scale homogeneity of the reference glasses. Together with previously published isotopic data from ten other laboratories, preliminary reference and information values as well as their uncertainties at the 95% confidence level were determined for H, O, Li, B, Si, Ca, Sr, Nd, Hf, Pb, Th and U isotopes using the recommendations of the International Association of Geoanalysts for certification of reference materials. Our results indicate that GSD‐1G and the MPI‐DING glasses are suitable reference materials for microanalytical and bulk analytical purposes. 相似文献