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191.
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
192.
D.O. Demir U. Dogan 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
This paper reports on the estimation of changes of a GPS-based crustal deformation field as function of the observing session duration. This investigation was carried out on the Marmara Continuous GPS Network (Marmara region) by using GPS data collected on a set of 10 stations during the period 2002.50–2005.47 The GPS observations were processed in the ITRF 2005 reference frame using Bernese v5.0 software. 相似文献
193.
高能束流(High Energy Density Beam)加工技术包含了以激光束、电
子束和等离子弧为热源对材料或构件进行特种加工的各类工艺方法.高能束流焊(或高能密度焊)是指焊接功率密度比通常的氩弧焊(TIG、MIG)或CO2气体保护焊高的一类焊接方法.严格地讲,焊接能量和焊接功率密度是2个不同的概念,但二者具有相关性. 相似文献
194.
U. Weinbach S. Schön 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Processing data from Global Navigation Satellite Systems (GNSS) always requires time synchronization between transmitter and receiver clocks. Due to the limited stability of the receiver’s internal oscillator, the offset of the receiver clock with respect to the system time has to be estimated for every observation epoch or eliminated by processing differences between simultaneous observations. If, in contrast, the internal oscillator of the receiver is replaced by a stable atomic clock one can try to model the receiver clock offset, instead of estimating it on an epoch-by-epoch basis. In view of the progress made in the field of high-precision frequency standards we will investigate the technical requirements for GNSS receiver clock modeling at the carrier phase level and analyze its impact on the precision of the position estimates. 相似文献
195.
R. Duffard K. Kumar S. Pirrotta M. Salatti M. Kubínyi U. Derz R.M.G. Armytage S. Arloth L. Donati A. Duricic J. Flahaut S. Hempel A. Pollinger S. Poulsen 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
We propose a dual-rendezvous mission, targeting near-Earth asteroids, including sample-return. The mission, Asteroid Sampling Mission (ASM), consists of two parts: (i) flyby and remote sensing of a Q-type asteroid, and (ii) sampling of a V-type asteroid. The targeted undifferentiated Q-type are found mainly in the near-Earth space, and to this date have not been the target of a space mission. We have chosen, for our sampling target, an asteroid from the basaltic class (V-type), as asteroids in this class exhibit spectral signatures that resemble those of the well-studied Howardite–Eucrite–Diogenite (HED) meteorite suite. With this mission, we expect to answer specific questions about the links between differentiated meteorites and asteroids, as well as gain further insight into the broader issues of early Solar System (SS) evolution and the formation of terrestrial planets. To achieve the mission, we designed a spacecraft with a dry mass of less than 3 tonnes that uses electric propulsion with a solar-electric power supply of 15 kW at 1 Astronomical Unit (AU). The mission includes a series of remote sensing instruments, envisages landing of the whole spacecraft on the sampling target, and employs an innovative sampling mechanism. Launch is foreseen to occur in 2018, as the designed timetable, and the mission would last about 10 years, bringing back a 150 g subsurface sample within a small re-entry capsule. This paper is a work presented at the 2008 Summer School Alpbach,“Sample return from the Moon, asteroids and comets” organized by the Aeronautics and Space Agency of the Austrian Research Promotion Agency. It is co-sponsored by ESA and the national space authorities of its Member and Co-operating States, with the support of the International Space Science Institute and Austrospace. 相似文献
196.
Bartley William C. McCracken Kenneth G. Rao U.R. 《IEEE transactions on aerospace and electronic systems》1967,(2):230-235
This paper describes an aspect system flown on PIONEERS VI and VII2 which incorporates an extremely accurate adaptive digital computer in order to define rigorously equal time intervals which are submultiples of the spacecraft spin period. The several submultiples which compose the complete spin period exhibit equality to within 2.5 parts in 105. This system has potential applications in other experiments involving the study of the angular dependence of cosmic radiation and other physical phenomena being measured by a single directional detector mounted on spin-stabilized spacecraft. Included here are the scientific goals for this experiment, system restraints, and the generalized system operation. Some details on specific logic and hardware implementation for the Pioneer experiments are included along with in-flight performance evaluation of the system aboard PIONEER VI. 相似文献
197.
P. Lemaire K. Wilhelm U. Schühle W. Curdt A.I. Poland S.D. Jordan R.J. Thomas D.M. Hassler J.-C. Vial 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1997,20(12):2249-2258
The increase of our understanding of the processes acting in the solar corona and maintaining it is strongly dependent on the quality of the data that are obtained to check theories. The fine structure of the solar atmosphere seen from the photosphere and extending to the hottest parts of the corona requires data with high resolution in all parameter space (angular, spectral and temporal). To constrain the hypotheses that are proposed to describe the solar corona, it is necessary to establish an accurate energy budget taking into account the processes which are acting from the chromosphere to the corona. Some requirements can be established and compared with the data collected so far (or about to be collected) with the present SUMER (Solar Utraviolet Measurements of Emitted Radiations) instrumentation. 相似文献
198.
199.
J. P. McFadden C. W. Carlson D. Larson J. Bonnell F. Mozer V. Angelopoulos K.-H. Glassmeier U. Auster 《Space Science Reviews》2008,141(1-4):477-508
Early observations by the THEMIS ESA plasma instrument have revealed new details of the dayside magnetosphere. As an introduction to THEMIS plasma data, this paper presents observations of plasmaspheric plumes, ionospheric ion outflows, field line resonances, structure at the low latitude boundary layer, flux transfer events at the magnetopause, and wave and particle interactions at the bow shock. These observations demonstrate the capabilities of the plasma sensors and the synergy of its measurements with the other THEMIS experiments. In addition, the paper includes discussions of various performance issues with the ESA instrument such as sources of sensor background, measurement limitations, and data formatting problems. These initial results demonstrate successful achievement of all measurement objectives for the plasma instrument. 相似文献
200.
K. Scherer H. Fichtner T. Borrmann J. Beer L. Desorgher E. Flükiger H.-J. Fahr S. E. S. Ferreira U. W. Langner M. S. Potgieter B. Heber J. Masarik N. Shaviv J. Veizer 《Space Science Reviews》2006,127(1-4):467-465
In recent years the variability of the cosmic ray flux has become one of the main issues interpreting cosmogenic elements
and especially their connection with climate. In this review, an interdisciplinary team of scientists brings together our
knowledge of the evolution and modulation of the cosmic ray flux from its origin in the Milky Way, during its propagation
through the heliosphere, up to its interaction with the Earth’s magnetosphere, resulting, finally, in the production of cosmogenic
isotopes in the Earth’ atmosphere. The interpretation of the cosmogenic isotopes and the cosmic ray – cloud connection are
also intensively discussed. Finally, we discuss some open questions. 相似文献