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201.
Kleczek J. van Gent R. H. Rutten Robert J. de Munck J. C. Slottje C. Severne G. Pecker Jean-Claude Postma H. Grishchuk L. P. Niewenhuijzen H. Schuiling R. D. van Beek H. F. Reijnen G. C. M. Heidmann Jean Lemaire J. Bleeker Johan Icke V. Neéman Y. Feast M. W. de Graaff W. 《Space Science Reviews》1986,43(3-4):383-396
Space Science Reviews - 相似文献
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Low-thrust transfers between preset orbits are considered in the presence of perturbations of different origin. A simple method of finding the transfer trajectory is suggested, based on linearization of motion near reference orbits. The required accuracy of calculations is achieved by way of increasing the number of reference orbits. The method can also be used in the case of a large number of revolutions around the attracting center: no averaging of motion is required in this case. The suggested method is applicable as well, when the final orbit is specified partially and when there are constraints on the thrust direction. The optimal solution to the linearized problem is not optimal for the original problem; closeness of solutions to these two problems is estimated using a numerical example. Capabilities of the method are also illustrated by examples. 相似文献
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The RUSI ‘Space and UK National Security’ conference was held in London on 2 October 2012 and, with the ‘Cyber Alliances: Strategy Partnerships in Cyber Space’ conference’ of 14–15 November 2012, brought together space and cyberspace specialists from more than 15 countries, across four continents. Alixe Buckerfield de la Roche reports on key points discussed across both conferences: (1) space as a shared domain, and building resilience; (2) governance; (3) national responses to space security; (4) partnerships and alliances, space situational awareness, space debris, and new initiatives; (5) the space–cyberspace merger; and (6) commercial and military sectors. Consensus on critical areas for further action emerged, and for that reason the conjunction of the two conferences was significant. 相似文献
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J. Gorosabel A. de Ugarte Postigo A.J. Castro-Tirado I. Agudo M. Jelínek S. Leon T. Augusteijn J.P.U. Fynbo M.J. Michałowski D. Xu P. Ferrero D.A. Kann A. LLorente M. Bremer J.-M. Winters C.C. Thöne J. Cepa 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
We present the preliminary results of the recent Hα narrow-band imaging carried out for NGC 2770 with the Gran Telescopio Canarias (GTC) equipped with OSIRIS. We put the polarization measurements reported in Gorosabel et al. (2010) for SN 2007uy and SN 2008D in the context of the morphological information inferred from the Hα imaging. We estimated the orientation of the interstellar polarization (ISP) at the position of SN 2007uy and, most interestingly, at the site of SN 2008D which has been subject of an intensive debate due to its possible connection with Gamma-Ray Bursts (GRBs). The Hα imaging reveals a clumpy interstellar medium (ISM) composed of hundreds of compact emitting regions, for which we determined their sizes. The derived size for the Hα emitting region coincident with SN 2008D is consistent with the ISM cell size limits imposed by Gorosabel et al. (2010) based on millimetric data. A deeper data analysis is under way and will be published elsewhere. This article represents the first attempt to study the site of a possible GRB-like event combining millimetric, polarimetric and narrow-band data. 相似文献
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OTTAVY Xavier 《中国航空学报》2011,(3):235-242
In order to gain a better knowledge of the mechanisms and to calibrate computational fluid dynamics (CFD) tools including both Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES),a detailed and accurate experimental study of corner stall in a linear compressor cascade has been carried out.Data are taken at a Reynolds number of 382 000 based on blade chord and inlet velocity.At first,inlet flow boundary layer is surveyed using hot-wire anemometry.Then in order to investigate the effects of incidence,measurements are acquired at five incidences,including static pressures on both blade and endwall surfaces measured by pressure taps and the total pressure losses of outlet flow measured by a five-hole pressure probe.The maximum losses as well as the extent of losses of the corner stall are presented as a function of the investigated incidences. 相似文献