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Paul A. Crowther Joanne L. Bibby James P. Furness J. Simon Clark 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
We highlight how the downward revision in the distance to the star cluster associated with SGR 1806–20 by Bibby et al. (2008) reconciles the apparent low contamination of BATSE short GRBs by intense flares from extragalactic magnetars without recourse to modifying the frequency of one such flare per 30 years per Milky Way galaxy. We also discuss the variety in progenitor initial masses of magnetars based upon cluster ages, ranging from ∼50 M⊙ for SGR 1806–20 and AXP CXOU J164710.2–455216 in Westerlund 1 to ∼17 M⊙ for SGR 1900+14 according to Davies et al. (2009) and presumably also 1E 1841–045 if it originated from one of the massive RSG clusters #2 or #3. 相似文献
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Evgenia V. Troitskaia Irene V. Arkhangelskaja Leonty I. Miroshnichenko Andrey I. Arkhangelsky 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
By the data on intensity-time profiles of the neutron capture line of 2.223 MeV we have studied some characteristics of two solar flares, 28 October 2003 and 20 January 2005 (INTEGRAL and CORONAS-F observations, respectively). The SINP code was applied making allowance for the main processes of neutron interactions and deceleration in the solar plasma, character of neutron source, losses of neutrons and density model of the solar atmosphere. Comparison of the computed time profiles of 2.223 MeV line with observed ones for the flare of 28 October 2003 confirms the results obtained earlier for three other flares. Namely, the effect of density enhancement (EDE) in the sub-flare region, as well as the variations (hardening) of accelerated particle spectrum in the course of the event have been confirmed. The usual modeling procedure by the SINP code, however, seems to be inapplicable to the event of 20 January 2005. Possible causes of density enhancements during some flares and peculiarities of the 20 January 2005 flare are discussed. 相似文献
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Joanne Irene Gabrynowicz 《Space Policy》1997,13(3):229-244
A ground-level view of Earth observations reveals that emerging ground segments are of at least two major categories: those that are satellite-driven and which have top-down organizations and those that are data-driven and organized from the bottom up. Or put differently, the former are generally data users. A ground-level perspective also suggests that continually rising scientific and economic value of data and decreasing national budgets require balancing satellite investment with effective ground segment evolution to provide demonstrable reasons to continue funding both satellites and ground activities. 相似文献
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The work of the US National Satellite Land Remote Sensing Data Archive Advisory Committee: 1998–2000
Earth observation data have been acquired and stored since the early 1970 s. One of the world's largest, and most important, repositories for land satellite data is the Earth Resources Observation Systems (EROS) Data Center (EDC). It is a data management, systems development and research field center for the US Geological Survey's (USGS) National Mapping Division in Sioux Falls, SD, USA. It was established in the early 1970 s and, in 1992, the US Congress established the National Satellite Land Remote Sensing Data Archive at EDC. Although data have been acquired and stored for decades, the world's remote sensing community has only recently begun to address long-term data preservation and access. One such effort was made recently by remote sensing leaders from academia, industry and government as members of a federal advisory committee from 1998 to 2000.2 This paper provides a brief account of the Committee's work product. 相似文献
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Neutrinos are fundamental particles in the collapse of massive stars. Because of their weakly interacting nature, neutrinos can travel undisturbed through the stellar core and be direct probes of the still uncertain and fascinating supernova mechanism. Intriguing recent developments on the role of neutrinos during the stellar collapse are reviewed, as well as our current understanding of the flavor conversions in the stellar envelope. The detection perspectives of the next burst and of the diffuse supernova background will be also outlined. High-energy neutrinos in the GeV-PeV range can follow the MeV neutrino emission. Various scenarios concerning the production of high-energy neutrinos are discussed. 相似文献
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Dominik Quantius Daniel Schubert Volker Maiwald Rosa París Lopéz Jens Hauslage Wolfgang Seboldt Ondrej Doule Irene Lia Schlacht Stephen Ransom 《Acta Astronautica》2014
An effective and self-sustainable artificial habitat design is essential for human spaceflight and expansion of mankind into orbit or towards other celestial bodies. There are two approaches that need to be implemented in future sustainable habitats: the use of re-cycling technologies in order to gain experience in closed-loop processes and the primary production of resource materials using In Situ Resource Utilisation (ISRU) principles. Various products will be provided and, where applicable, recycled in such a system taking into account basic human factors requirements such as crew work load capacity, safety and well-being, namely: 相似文献
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Irene R.A.E. Snger-Bredt 《Acta Astronautica》1980,7(12):1451-1455
To day's predominant opinion about the fact of a finitely large, expanding universe is based on observations of a distance dependent red shift in the spectrum of cosmic light sources, as reported about fifty years ago by the American astronomer E. P. Hubble.
Doubts appeared in the meantime about this hypothesis of expansion. Those as well as the prerequisites to alternate models of the universe and its evolution will be treated. 相似文献
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Joanne Irene Gabrynowicz 《Space Policy》1993,9(4):319-328
After nearly a decade of attempting to guide the complex process of land remote sensing in the US, the 1984 Land Remote Sensing Commercialization Act was repealed. In its place, Congress passed the Land Remote Sensing Policy Act of 1992. This action was prompted by what many observers consider a failed attempt at commercialization and the inability of the old law's provisions to meet the compelling needs of scientific research. The new law attempts to address these failures and, in many respects, is successful. Nonetheless it still embodies some of the problems associated with the earlier law. This article compares the provisions of the two laws and provides an analysis of the new law's strengths and weaknesses. 相似文献
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Maurice M. Averner Berrien Moore III Irene Bartholomew Robert Wharton 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,4(12):231-239
Concepts of biologically-based regenerative life support systems anticipate the use of photosynthetic organisms for air revitalization. However, mismatches in the rates of production and uptake of oxygen or carbon dioxide between the crew and the plants will lead to an accumulation or depletion of these gases beyond tolerable limits. One method for correcting these atmospheric changes is to use physicochemical devices. This would conflict with the constraint of minimal size and weight imposed upon the successful development of a competitive bioregenerative system. An alternate control strategy is based upon reducing the gas exchange mismatch by manipulation of those environmental parameters known to affect plant or algae gas exchange ratios. We have initiated a research program using a dual approach of mathematical modelling and laboratory experimentation aimed at examining the gas exchange characteristics of artificial animal/plant systems closed to the ambient atmosphere. Our goal is to develop control techniques and management strategies for maintaining the atmospheric levels of carbon dioxide and oxygen at physiological levels. A mathematical model simulating the atmospheric behavior in these systems has been developed and an experimental gas-closed system has been constructed. These will be described and preliminary results will be presented. 相似文献
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