排序方式: 共有35条查询结果,搜索用时 15 毫秒
11.
Anthony Boccaletti Jean Schneider Wes Traub Pierre-Olivier Lagage Daphne Stam Raffaele Gratton John Trauger Kerri Cahoy Frans Snik Pierre Baudoz Raphael Galicher Jean-Michel Reess Dimitri Mawet Jean-Charles Augereau Jenny Patience Marc Kuchner Mark Wyatt Eric Pantin Anne-Lise Maire Christophe Vérinaud Samuel Ronayette Didier Dubreuil Michiel Min Michiel Rodenhuis Dino Mesa Russ Belikov Olivier Guyon Motohide Tamura Naoshi Murakami Ingrid Mary Beerer 《Experimental Astronomy》2012,34(2):355-384
SPICES (Spectro-Polarimetric Imaging and Characterization of Exoplanetary Systems) is a five-year M-class mission proposed to ESA Cosmic Vision. Its purpose is to image and characterize long-period extrasolar planets and circumstellar disks in the visible (450?C900 nm) at a spectral resolution of about 40 using both spectroscopy and polarimetry. By 2020/2022, present and near-term instruments will have found several tens of planets that SPICES will be able to observe and study in detail. Equipped with a 1.5 m telescope, SPICES can preferentially access exoplanets located at several AUs (0.5?C10?AU) from nearby stars (<25 pc) with masses ranging from a few Jupiter masses to Super Earths (??2 Earth radii, ??10 M??) as well as circumstellar disks as faint as a few times the zodiacal light in the Solar System. 相似文献
12.
13.
Marco Massa Francesca Pacor Lucia Luzi Dino Bindi Giuliano Milana Fabio Sabetta Antonella Gorini Sandro Marcucci 《Bulletin of Earthquake Engineering》2010,8(5):1175-1187
The Italian strong-motion database was created during a joint project between Istituto Nazionale di Geofisica e Vulcanologia
(INGV, Italian Institute for Geophysics and Vulcanology) and Dipartimento della Protezione Civile (DPC, Italian Civil Protection). The aim of the project was the collection, homogenization and distribution of strong motion data acquired in Italy in the
period 1972–2004 by different institutions, namely Ente Nazionale per l’Energia Elettrica (ENEL, Italian electricity company), Ente per le Nuove tecnologie, l’Energia e l’Ambiente (ENEA, Italian energy and environment organization) and DPC. Recently the strong-motion data relative to the 23th December 2009, Parma (Mw = 5.4 and Mw = 4.9) and to the April
2009 L’Aquila sequences (13 earthquakes with 4.1 ≤ Mw ≤ 6.3) were included in the Italian Accelerometric Archive (ITACA) database
(beta release). The database contains 7,038 waveforms from analog and digital instruments, generated by 1.019 earthquakes
with magnitude up to 6.9 and can be accessed on-line at the web site . The strong motion data are provided in the unprocessed and processed versions. This article describes the steps followed
to process the acceleration time series recorded by analogue and digital instruments. The procedures implemented involve:
baseline removal, instrumental correction, band pass filtering with acausal filters, integration of the corrected acceleration
in order to obtain velocity and displacement waveforms, computation of acceleration response spectra and strong motion parameters.
This procedure is applied to each accelerogram and it is realised to preserve the low frequency content of the records. 相似文献
14.
John Douglas Sinan Akkar Gabriele Ameri Pierre-Yves Bard Dino Bindi Julian J. Bommer Sanjay Singh Bora Fabrice Cotton Boumédiène Derras Marcel Hermkes Nicolas Martin Kuehn Lucia Luzi Marco Massa Francesca Pacor Carsten Riggelsen M. Abdullah Sandıkkaya Frank Scherbaum Peter J. Stafford Paola Traversa 《Bulletin of Earthquake Engineering》2014,12(1):341-358
This article presents comparisons among the five ground-motion models described in other articles within this special issue, in terms of data selection criteria, characteristics of the models and predicted peak ground and response spectral accelerations. Comparisons are also made with predictions from the Next Generation Attenuation (NGA) models to which the models presented here have similarities (e.g. a common master database has been used) but also differences (e.g. some models in this issue are nonparametric). As a result of the differing data selection criteria and derivation techniques the predicted median ground motions show considerable differences (up to a factor of two for certain scenarios), particularly for magnitudes and distances close to or beyond the range of the available observations. The predicted influence of style-of-faulting shows much variation among models whereas site amplification factors are more similar, with peak amplification at around 1s. These differences are greater than those among predictions from the NGA models. The models for aleatory variability (sigma), however, are similar and suggest that ground-motion variability from this region is slightly higher than that predicted by the NGA models, based primarily on data from California and Taiwan. 相似文献
15.
Cinzia Belmonte Dino Boccaletti Giuseppe Pucacco 《Celestial Mechanics and Dynamical Astronomy》2006,95(1-4):101-116
We investigate the dynamics in a galactic potential with two reflection symmetries. The phase-space structure of the real system is approximated with a resonant detuned normal form constructed with the method based on the Lie transform. Attention is focused on the stability properties of the axial periodic orbits that play an important role in galactic models. Using energy and ellipticity as parameters, we find analytical expressions of bifurcations and compare them with numerical results available in the literature. 相似文献
16.
Microzonation of Potenza (Southern Italy) in terms of spectral intensity ratio using joint analysis of earthquakes and ambient noise 总被引:1,自引:1,他引:0
Angelo Strollo Stefano Parolai Dino Bindi Leonardo Chiauzzi Rossella Pagliuca Marco Mucciarelli Jochen Zschau 《Bulletin of Earthquake Engineering》2012,10(2):493-516
A temporary seismic network composed of 11 stations was installed in the city of Potenza (Southern Italy) to record local
and regional seismicity within the context of a national project funded by the Italian Department of Civil Protection (DPC).
Some stations were moved after a certain time in order to increase the number of measurement points, leading to a total of
14 sites within the city by the end of the experiment. Recordings from 26 local earthquakes (Ml 2.2−3.8 ) were analyzed to compute the site responses at the 14 sites by applying both reference and non-reference site techniques.
Furthermore, the Spectral Intensity (SI) for each local earthquake, as well as their ratios with respect to the values obtained
at a reference site, were also calculated. In addition, a field survey of 233 single station noise measurements within the
city was carried out to increase the information available at localities different from the 14 monitoring sites. By using
the results of the correlation analysis between the horizontal-to-vertical spectral ratios computed from noise recordings
(NHV) at the 14 selected sites and those derived by the single station noise measurements within the town as a proxy, the
spectral intensity correction factors for site amplification obtained from earthquake analysis were extended to the entire
city area. This procedure allowed us to provide a microzonation map of the urban area that can be directly used when calculating
risk scenarios for civil defence purposes. The amplification factors estimated following this approach show values increasing
along the main valley toward east where the detrital and alluvial complexes reach their maximum thickness. 相似文献
17.
Giuseppe Pucacco Dino Boccaletti Cinzia Belmonte 《Celestial Mechanics and Dynamical Astronomy》2008,102(1-3):163-176
The phase-space structure of two families of galactic potentials is approximated with a resonant detuned normal form. The normal form series is obtained by a Lie transform of the series expansion around the minimum of the original Hamiltonian. Attention is focused on the quantitative predictive ability of the normal form. We find analytical expressions for bifurcations of periodic orbits and compare them with other analytical approaches and with numerical results. The predictions are quite reliable even outside the convergence radius of the perturbation and we analyze this result using resummation techniques of asymptotic series. 相似文献
18.
Brandon T. Overstreet Clifford S. Riebe John K. Wooster Leonard S. Sklar Dino Bellugi 《地球表面变化过程与地形》2016,41(1):130-142
We present a set of river management tools based on a recently developed method for estimating the amount of salmon spawning habitat in coarse‐bedded rivers. The method, which was developed from a mechanistic model of redd building by female salmon, combines empirical relationships between fish length, redd area, and the sizes of particles moved by fish during spawning. Model inputs are the grain‐size indices D50 and D84 and an estimate of female fish length, which is used to predict the size of the redd that they will build and the size of the largest particle that they can move on the bed. Outputs include predictions of the fraction of the bed that the fish can use for redd building and the number of redds that they can build within the useable area. We cast the model into easy‐to‐use look‐up tables, charts, an Excel worksheet, a JavaScript web applet, and a MATLAB user interface. We explain how these tools can be used in a new, mechanistic approach to assessing spawning substrates and optimizing gravel augmentation projects in coarse‐bedded rivers. © 2016 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd. 相似文献
19.
Both natural and synthetic crystals of whewellite (CaC2O4·H2O, sp.g. P21/c) occur commonly as twins. The geometrical, reticular and structural features of the most important twin law, twin plane (100), and the dubious law ( \(\overline {\text{1}} \) 01) were investigated. The strict application of the periodic bond chain (PBC) theory (Hartman and Perdok 1955) makes possible the identification of original composition planes (OCP). Following the OCP analysis it has been deduced that the energy necessary to produce a (100) twin is very low. This is evidenced by the easy reciprocal arrangement of the two crystal structures which can be shown in two slightly different ways, i.e., by a (100) reflection with a mean [0, 1/2, ?a 0cosβ] translation and a weak relaxation (from 0.1 to 0.25 Å) of the common interface. In OCP an important role is played by water molecules. With regard to ( \(\overline {\text{1}} \) 01) twinning, the geometrical and reticular agreement is not matched by the structural situation. The structural and growth approach to the twin laws of whewellite therefore justifies the very common occurrence only of (100) twinned crystals. 相似文献
20.
Marco Ciolli Massimiliano de Franceschi Roberto Rea Alfonso Vitti Dino Zardi Paolo Zatelli 《Transactions in GIS》2004,8(2):191-209
The ability to manage and process fully three‐dimensional information has only recently been made available for a few Geographical Information Systems (GIS). An example of integrated and complementary use of 2D and 3D GRASS modules for the evaluation and representation of thermally induced slope winds over complex terrain is presented. The analytic solution provided by Prandtl (1942) to evaluate wind velocity and (potential) temperature anomaly induced by either diurnal heating or nocturnal cooling on a constant angle slope is adopted to evaluate wind and temperature profiles at any point over both idealised and real complex terrain. As these quantities depend on the slope angle of the ground and on the distance from the slope surface suitable procedures are introduced to determine the coordinate n of a point in the 3D volume measured along the direction locally normal to the terrain surface. A new GRASS module has been developed to evaluate this quantity and to generate a 3D raster file where each cell is assigned the value of the cell on the surface belonging to the normal vector. The application of the algorithm implemented in GRASS to an ideal valley and to a real valley close to the city of Trento in the Alps provides results in accordance with data reported in the literature. An extension of Prandtl's (1942) model to take into account humidity and evaporation processes on the soil is also proposed and implemented. 相似文献