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331.
Benjamin P. Weiss Jérôme Gattacceca Sabine Stanley Pierre Rochette Ulrich R. Christensen 《Space Science Reviews》2010,152(1-4):341-390
The large-scale compositional structures of planets are primarily established during early global differentiation. Advances in analytical geochemistry, the increasing diversity of extraterrestrial samples, and new paleomagnetic data are driving major changes in our understanding of the nature and timing of these early melting processes. In particular, paleomagnetic studies of chondritic and small-body achondritic meteorites have revealed a diversity of magnetic field records. New, more sensitive and highly automated paleomagnetic instrumentation and an improved understanding of meteorite magnetic properties and the effects of shock, weathering, and other secondary processes are permitting primary and secondary magnetization components to be distinguished with increasing confidence. New constraints on the post-accretional histories of meteorite parent bodies now suggest that, contrary to early expectations, few if any meteorites have been definitively shown to retain records of early solar and protoplanetary nebula magnetic fields. However, recent studies of pristine samples coupled with new theoretical insights into the possibility of dynamo generation on small bodies indicate that some meteorites retain records of internally generated fields. These results indicate that some planetesimals formed metallic cores and early dynamos within just a few million years of solar system formation. 相似文献
332.
Where does the stone go when we drop it? Development of French schoolchildren’s knowledge of gravity
Sören Frappart Valérie Frède 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2010
In this study, we explored children’s knowledge of gravity at different ages (5–6, 7–8, and 9–10 years), by asking the same question (“Where does a stone go when we drop it?”) in three different contexts (on Earth, in a spaceship orbiting the Earth, and on the Moon). We tested the influence of context and children’s age on both the answers and the justifications they provided. We expected that children of all ages would find it easier to make correct predictions in the Earth context than in the other two contexts. We were also interested in the kinds of justification children construct and how these justifications change during ontogenesis. Seventy-two French children were individually interviewed at their school. None of them had received any direct teaching about gravity. Results showed that children found it easier to predict the fall of the stone on Earth than its behaviour in the other two contexts, but that the younger children predicted the fall of the stone on the Moon more accurately than the older children. This unusual developmental effect only occurred for the Moon context. We also found that the categories of justifications changed with age, with a move away from intuitive considerations towards mechanistic ones. 相似文献
333.
A stable, observable liquid-gas interface was realized in an experimental cell (3 × 2 × 1 cm) under microgravity conditions. The liquid used was an aqueous 6.24 10?3 molal solution of n-heptanol. A temperature gradient, established at the interface, resulted in the build-up of a Marangoni convection cell with the liquid flowing in an unusual direction (i.e. at the surface the liquid flowed from the cold to the hot side).The same experiment on Earth gives rise to a Marangoni cell superimposed on buoyancy cells. The Marangoni and the buoyancy cells then turn in opposite directions. 相似文献
334.
335.
M. Van Der Klis 《Space Science Reviews》1993,62(1-2):173-202
The observational information on X-ray binaries that was collected with the 80 cm2 auxiliary X-ray detector onboard the COS-B gamma-ray satellite is reviewed. The results illustrate that in the study of X-ray binaries observations of long duration are extremely effective, even when using a small instrument. 相似文献
336.
B. Ehmann L. Balázs É. Fülöp R. Hargitai P. Kabai B. Péley T. Pólya A. Vargha J. László 《Acta Astronautica》2011,68(9-10):1560-1566
This paper is about a pilot application of narrative psychological content analysis in the psychological status monitoring of Crew 71 of a space analog simulation environment, the Mars Desert Research Station (MDRS). Both the method and its theoretical framework, Scientific Narrative Psychology, are original developments by Hungarian psychologists [5] (László, 2008). The software was NooJ, a multilingual linguistic development environment [11] (Silberztein, 2008). Three measures were conceptualized and assessed: emotional status, team spirit and subjective physical comfort. The results showed the patterns of these three measures on a daily basis at group level, and allowed for detecting individual differences as well. The method is adaptable to languages involved in space psychology, e.g. Russian, French and German in addition to English. 相似文献
337.
338.
We present the results of a study aimed at determining the 12C/13C ratio in two samples of planetary nebulae (PNe) by means of mm-wave observations of 12CO and 13CO. The first group includes six PNe which have been observed in the 3He+ hyperfine transition; the other group consists of 23 nebulae with rich molecular envelopes. We have determined the isotopic ratio in 14 objects and the results indicate a range of values between 9 and 23. In particular, three PNe have ratios well below the value predicted by standard evolutionary models ( 20), indicating that some extra-mixing process has occurred in these stars. We briefly discuss the implications of our results for standard and nonstandard stellar nucleosynthesis. 相似文献
339.
David H. Rodgers Patricia M. Beauchamp Laurence A. Soderblom Robert H. Brown Gun-Shing Chen Meemong Lee Bill R. Sandel David A. Thomas Robert T. Benoit Roger V. Yelle 《Space Science Reviews》2007,129(4):309-326
MICAS is an integrated multi-channel instrument that includes an ultraviolet imaging spectrometer (80–185 nm), two high-resolution
visible imagers (10–20 μrad/pixel, 400–900 nm), and a short-wavelength infrared imaging spectrometer (1250–2600 nm). The wavelength ranges were chosen
to maximize the science data that could be collected using existing semiconductor technologies and avoiding the need for multi-octave
spectrometers. It was flown on DS1 to validate technologies derived from the development of PICS (Planetary Imaging Camera
Spectrometer). These technologies provided a novel systems approach enabling the miniaturization and integration of four instruments
into one entity, spanning a wavelength range from the UV to IR, and from ambient to cryogenic temperatures with optical performance
at a fraction of a wavelength. The specific technologies incorporated were: a built-in fly-by sequence; lightweight and ultra-stable,
monolithic silicon-carbide construction, which enabled room-temperature alignment for cryogenic (85–140 K) performance, and
provided superb optical performance and immunity to thermal distortion; diffraction-limited, shared optics operating from
80 to 2600 nm; advanced detector technologies for the UV, visible and short-wavelength IR; high-performance thermal radiators
coupled directly to the short-wave infrared (SWIR) detector optical bench, providing an instrument with a mass less than 10
kg, instrument power less than 10 W, and total instrument cost of less than ten million dollars. The design allows the wavelength
range to be extended by at least an octave at the short wavelength end and to ∼50 microns at the long wavelength end. Testing
of the completed instrument demonstrated excellent optical performance down to 77 K, which would enable a greatly reduced
background for longer wavelength detectors. During the Deep Space 1 Mission, MICAS successfully collected images and spectra
for asteroid 9969 Braille, Mars, and comet 19/P Borrelly. The Borrelly encounter was a scientific hallmark providing the first
clear, high resolution images and excellent, short-wavelength infrared spectra of the surface of an active comet’s nucleus. 相似文献
340.