排序方式: 共有54条查询结果,搜索用时 31 毫秒
1.
UN-affiliated regional centres for space science and technology education are being established or are in operation in Africa (Morocco, Nigeria), Asia and the Pacific (India), Latin America and the Caribbean (Brazil, Mexico), and Western Asia (Jordan). Education curricula at the university level, embracing remote sensing, satellite communications, satellite meteorology, and space science have been developed for these centres. This article briefly reports on the structure of the most recent updated education curricula in the four disciplines that have been made available for implementation in 2002 and 2003, in the six official languages of the United Nations. This is also an effort to bridge the gap between such education curricula as they vary significantly between nations and among educational institutions in nations. 相似文献
2.
3.
F. Durret J. S. Kaastra J. Nevalainen T. Ohashi N. Werner 《Space Science Reviews》2008,134(1-4):51-70
An excess over the extrapolation to the extreme ultraviolet and soft X-ray ranges of the thermal emission from the hot intracluster
medium has been detected in a number of clusters of galaxies. We briefly present each of the satellites (EUVE, ROSAT PSPC
and BeppoSAX, and presently XMM-Newton, Chandra and Suzaku) and their corresponding instrumental issues, which are responsible
for the fact that this soft excess remains controversial in a number of cases. We then review the evidence for this soft X-ray
excess and discuss the possible mechanisms (thermal and non-thermal) which could be responsible for this emission. 相似文献
4.
This report describes recent progress in the UN Basic Space Science Initiative (UNBSSI), which aims to facilitate space science education and research, and attendant resources in developing countries. In addition to holding workshops across the developing world, the UN Committee on the Peaceful Uses of Outer Space (COPUOS) successfully implemented the International Heliophysical Year (IHY) as a catalyst for improving understanding of the Sun and of solar-terrestrial physics. Building on this it is now preparing for the International Space Weather Initiative (ISWI). Achievements of the former are discussed, as are the goals and anticipated activities of the latter. 相似文献
5.
How do people describe the location of a target object to another? This task requires a reference object or frame and terms of reference. Traditional linguistic analyses have loosely organized perspectives around people, objects, or environments as reference objects, using reference terms based on a viewpoint or the intrinsic sides of an object, such as left, right, front, and back or based on the environment, such as north, south, east, and west. In actual communication, social, spatial, and cognitive factors may also affect perspective choice. We examine those factors by varying the spatial information (landmarks and cardinal directions), the communication task (relative cognitive burden to speakers and addressees), and the culture of participants (American and Japanese). Speakers used addressees' perspectives more when addressees had the greater cognitive burden. They also used landmarks and cardinal directions when they were available, especially to avoid difficult discriminations like left/right. Some cases appearing to be perspective taking can be interpreted as using a person as a landmark. Finally, terms like near indicating close proximity were preferred to far and to terms requiring projection of directions. Globally, perspective choices of American and Japanese samples were strikingly similar; that is, Japanese did not select addressees' perspectives more than Americans. The traditional linguistic analyses need to be enhanced to account for effects of cognitive, situational, and social factors. 相似文献
6.
Werner Schmutz 《Space Science Reviews》1993,66(1-4):253-261
A standard non-LTE Wolf-Rayet star atmosphere model is compared with an identical model but including line-blanketing. The structures of the two models are presented in detail and the implications of blanketed models for spectroscopic analyses are discussed. 相似文献
7.
Environmental reference systems for large-scale spaces 总被引:1,自引:1,他引:0
Human navigation in well-known environments is guided by stored memory representations of spatial information. In three experiments (N = 43) we investigated the role of different spatial reference systems when accessing information about familiar objects at different locations in the city in which the participants lived. Our results indicate that two independent reference systems underly the retrieval of spatial knowledge. Environmental characteristics, e.g., the streets at an intersection, determine which headings are easier to imagine at a given location and lead to differences in accessibility of spatial information (orientation-specific behavior). In addition, access to spatial information depends on the relative direction of a location with respect to the imagined heading, such that information about locations imagined in front of oneself is easier to access than about locations towards the back. This influence of an egocentric reference system was found for environmental knowledge as well as map-based knowledge. In light of these reference system effects, position-dependent models of spatial memory for large-scale environments are discussed. To account for the simultaneous effect of an environmental and an egocentric reference system, we present a 2-level model of spatial memory access. 相似文献
8.
9.
Markus J. Aschwanden Felix Scholkmann William Béthune Werner Schmutz Valentina Abramenko Mark C. M. Cheung Daniel Müller Arnold Benz Guennadi Chernov Alexei G. Kritsuk Jeffrey D. Scargle Andrew Melatos Robert V. Wagoner Virginia Trimble William H. Green 《Space Science Reviews》2018,214(2):55
Self-organization is a property of dissipative nonlinear processes that are governed by a global driving force and a local positive feedback mechanism, which creates regular geometric and/or temporal patterns, and decreases the entropy locally, in contrast to random processes. Here we investigate for the first time a comprehensive number of (17) self-organization processes that operate in planetary physics, solar physics, stellar physics, galactic physics, and cosmology. Self-organizing systems create spontaneous “order out of randomness”, during the evolution from an initially disordered system to an ordered quasi-stationary system, mostly by quasi-periodic limit-cycle dynamics, but also by harmonic (mechanical or gyromagnetic) resonances. The global driving force can be due to gravity, electromagnetic forces, mechanical forces (e.g., rotation or differential rotation), thermal pressure, or acceleration of nonthermal particles, while the positive feedback mechanism is often an instability, such as the magneto-rotational (Balbus-Hawley) instability, the convective (Rayleigh-Bénard) instability, turbulence, vortex attraction, magnetic reconnection, plasma condensation, or a loss-cone instability. Physical models of astrophysical self-organization processes require hydrodynamic, magneto-hydrodynamic (MHD), plasma, or N-body simulations. Analytical formulations of self-organizing systems generally involve coupled differential equations with limit-cycle solutions of the Lotka-Volterra or Hopf-bifurcation type. 相似文献
10.
Mika Ochiai Aimin NiuHeike Steffens Werner BaloghHans Haubold Mazlan OthmanTakao Doi 《Acta Astronautica》2014
The Human Space Technology Initiative was launched in 2010 within the framework of the United Nations Programme on Space Applications implemented by the Office for Outer Space Affairs of the United Nations. It aims to involve more countries in activities related to human spaceflight and space exploration and to increase the benefits from the outcome of such activities through international cooperation, to make space exploration a truly international effort. 相似文献