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341.
Szegö Karoly Crifo Jean-François Rodionov Alexander V. Fulle Marco 《Earth, Moon, and Planets》2002,90(1-4):435-443
The cameras carried onboard the flyby missions to comet P/Halleyin 1986 imaged the near nuclear jet activity fromseveral spatial
directions. The observed, very structured near nucleardust jets were considered at that timeas the result of dust emission
from well localized active surface regions(without supporting 3-D model computations, however).Based on the first, recently
developed 3-D gas dynamical model ofP/Halley's activity,we have been shown that jet features can be reproduced assuming ahomogeneous
dusty icenucleus surface. The dust in the collisional near nuclear comais concentrated along the gas flow discontinuities
resulting from thecomplicated surface orography, creating the visual impression ofdust jets. We present here the results of
these calculations forthe near nucleus dust distributions,and we compare them with the direct observations made during thethree
Halley flybys (Vega 1, Vega 2, and Giotto). 相似文献
342.
Rodrigo Leonardi Brian Williams Marco Bersanelli Ivan Ferreira Philip M. Lubin Peter R. Meinhold Hugh ONeill Nathan C. Stebor Fabrizio Villa Thyrso Villela Carlos A. Wuensche 《New Astronomy Reviews》2006,50(11-12):977
The COsmic Foreground Explorer (COFE) is a balloon-borne microwave polarimeter designed to measure the low-frequency and low-ℓ characteristics of dominant diffuse polarized foregrounds. Short duration balloon flights from the Northern and Southern Hemispheres will allow the telescope to cover up to 80% of the sky with an expected sensitivity per pixel better than 100 μK/deg2 from 10 GHz to 20 GHz. This is an important effort toward characterizing the polarized foregrounds for future CMB experiments, in particular the ones that aim to detect primordial gravity wave signatures in the CMB polarization angular power spectrum. 相似文献
343.
Marco Anzidei 《地学学报》1994,6(1):82-89
The Nepal region, between the Ganges plain and the Tibetan Plateau, shows the great effects of the orogenetic deformation which started between 40 and 55 Ma, following the collision between the Indian and Asiatic continental plates. Today the Himalayan chain and the Tibetan plateau are some of the best manifestations of the collision process.
Data from a geodetic network in Eastern Nepal were employed to study the motion of the crust in this recently evolved area. The data were collected by means of the Global Positioning System; this geodetic space technique can achieve a centimetric resolution in coordinate definition and baseline computation for observation sites, even those located at long distances away and it provides a powerful new tool for the comprehension of the dynamics of active tectonic regions. 相似文献
Data from a geodetic network in Eastern Nepal were employed to study the motion of the crust in this recently evolved area. The data were collected by means of the Global Positioning System; this geodetic space technique can achieve a centimetric resolution in coordinate definition and baseline computation for observation sites, even those located at long distances away and it provides a powerful new tool for the comprehension of the dynamics of active tectonic regions. 相似文献
344.
345.
Down‐faulting at the north‐west margins of the Gulf of Aqaba is inferred to have triggered a catastrophic sedimentary event at 2.3 ka that killed the Elat fringing coral reef. Whereas segments of the Holocene reef were perfectly fossilized and preserved beneath a veneer of siliciclastic sediments, other segments were abraded, settled by nomads, and later re‐submerged under 4 m of water. Repeated damage triggered by down‐throwing earthquakes degenerate the fringing reefs of the north‐west end of the gulf. Conversely, on the north‐eastern and southern parts of the gulf, where earthquakes uplift the margins, modern reefs are thriving, attached to uplifted fossil reef terraces. Therefore, coastal subsidence moderates the development of fringing coral reefs during the late Holocene sea‐level stand still. 相似文献
346.
This paper describes the Borexino detector and the high-radiopurity studies and tests that are integral part of the Borexino
technology and development. The application of Borexino to the detection and studies of geoneutrinos is discussed.
Talk given by M.G. Giammarchi 相似文献
347.
The classical treatment of implied differences on the orbital ellipticelements from the errors involved at an initial epoch is not possible toapply if we consider a long interval of integration, because there is atemporal variation for all the partial derivatives of the elements withrespect to all the variations in the initial ones. We propose asemi-analytical method to compute these partial derivatives by solving a setof initial value problems which are obtained from the planetary Lagrangeequations and their partial derivatives with respect to all the variationsin the initial elements. 相似文献
348.
349.
350.
Edoardo Barbero Luca Pandolfi Morteza Delavari Asghar Dolati Emilio Saccani Rita Catanzariti Valeria Luciani Marco Chiari Michele Marroni 《地学前缘(英文版)》2021,12(3):101106
The Durkan Complex is a key tectonic element of the Makran accretionary prism (SE Iran) and it has been interpreted as representing a continental margin succession. We present here a multidisciplinary study of the western Durkan Complex, which is based on new geological, stratigraphic, biostratigraphic data, as well as geochemical data of the volcanic and meta-volcanic rocks forming this complex. Our data show that this complex consists of distinct tectonic slices showing both non-metamorphic and very low-grade metamorphic deformed successions. Stratigraphic and biostratigraphic data allow us to recognize three types of successions. Type-I is composed by a Coniacian – early Campanian pelagic succession with intercalation of pillow lavas and minor volcaniclastic rocks. Type-II succession includes a volcanic sequence passing to a volcano-sedimentary sequence with Cenomanian pelagic limestones, followed by a hemipelagic sequence. This succession is characterized by abundant mass-transport deposits. Type-III succession includes volcanic and volcano-sedimentary sequences, which are stratigraphically covered by a Cenomanian platform succession. The latter is locally followed by a hemipelagic sequence. The volcanic rocks in the different successions show alkaline geochemical affinity, suggesting an origin from an oceanic within-plate setting. Our new results indicate that the western Durkan Complex represents fragments of seamounts tectonically incorporated in the Makran accretionary wedge during the latest Late Cretaceous–Paleocene. We propose that incorporation of seamounts in the frontal prism caused a shortening of the whole convergent margin and possibly contributed to controlling the deformation style in the Makran Accretionary Wedge during Late Cretaceous–Paleocene times. 相似文献