排序方式: 共有9条查询结果,搜索用时 78 毫秒
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Yen AS Gellert R Schröder C Morris RV Bell JF Knudson AT Clark BC Ming DW Crisp JA Arvidson RE Blaney D Brückner J Christensen PR DesMarais DJ de Souza PA Economou TE Ghosh A Hahn BC Herkenhoff KE Haskin LA Hurowitz JA Joliff BL Johnson JR Klingelhöfer G Madsen MB McLennan SM McSween HY Richter L Rieder R Rodionov D Soderblom L Squyres SW Tosca NJ Wang A Wyatt M Zipfel J 《Nature》2005,436(7047):49-54
The mineralogical and elemental compositions of the martian soil are indicators of chemical and physical weathering processes. Using data from the Mars Exploration Rovers, we show that bright dust deposits on opposite sides of the planet are part of a global unit and not dominated by the composition of local rocks. Dark soil deposits at both sites have similar basaltic mineralogies, and could reflect either a global component or the general similarity in the compositions of the rocks from which they were derived. Increased levels of bromine are consistent with mobilization of soluble salts by thin films of liquid water, but the presence of olivine in analysed soil samples indicates that the extent of aqueous alteration of soils has been limited. Nickel abundances are enhanced at the immediate surface and indicate that the upper few millimetres of soil could contain up to one per cent meteoritic material. 相似文献
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I. M. Rodionov A. Mukhammedov I. Poletaeva L. G. Romanova V. N. Yarigin 《Cellular and molecular life sciences : CMLS》1977,33(1):39-40
Summary The data obtained are evidence of the decreased resistance of sympathectomized animals to excitement caused by afferent stimuli. 相似文献
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本文的目的在于研究n型和p型硅单晶材料在外荷载作用下的变形性质。将云纹干涉和散斑干涉技术用于硅单晶材料变形性质的测定。试验结果表明,当载荷值小时,其变形量增大,而当载荷增加时,其变形增长量减小,这一现象证实了在硅晶体中存在着弱结合空位层,在外载荷作用下,排出晶体中的空位,致使晶体增密,或者说提高了硅单晶的密度所致。 相似文献
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V. B. Koshelev I. M. Rodionov I. B. Tsorin 《Cellular and molecular life sciences : CMLS》1979,35(2):204-204
Summary The frequency of spontaneous activity of single preganglionic fibres in the cervical sympathetic nerve of sympathectomized and intact animals was compared, and was found to be higher in the sympathectomized group, averaging 5.9±1.4 pulses per sec, compared with 2.3±0.5 in the control group. 相似文献
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Goetz W Bertelsen P Binau CS Gunnlaugsson HP Hviid SF Kinch KM Madsen DE Madsen MB Olsen M Gellert R Klingelhöfer G Ming DW Morris RV Rieder R Rodionov DS de Souza PA Schröder C Squyres SW Wdowiak T Yen A 《Nature》2005,436(7047):62-65
The ubiquitous atmospheric dust on Mars is well mixed by periodic global dust storms, and such dust carries information about the environment in which it once formed and hence about the history of water on Mars. The Mars Exploration Rovers have permanent magnets to collect atmospheric dust for investigation by instruments on the rovers. Here we report results from M?ssbauer spectroscopy and X-ray fluorescence of dust particles captured from the martian atmosphere by the magnets. The dust on the magnets contains magnetite and olivine; this indicates a basaltic origin of the dust and shows that magnetite, not maghemite, is the mineral mainly responsible for the magnetic properties of the dust. Furthermore, the dust on the magnets contains some ferric oxides, probably including nanocrystalline phases, so some alteration or oxidation of the basaltic dust seems to have occurred. The presence of olivine indicates that liquid water did not play a dominant role in the processes that formed the atmospheric dust. 相似文献
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