共查询到20条相似文献，搜索用时 46 毫秒
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V. A. Dorofeeva 《Geochemistry International》2016,54(1):7-26
Jupiter’s and Saturn’s regular satellites, which posses much ice, are currently thought to have been formed during the early evolution of the Solar System in circumplanetary protosatellite disks. Two of Saturn’s regular satellites—Titan and Enceladus—were experimentally proved to contain, along with water, other volatile components: molecular nitrogen, and methane (which are the major components of Titan’s atmosphere) and various nitrogen and carbon compounds in water plumes of Enceladus. The protomaterial of these rocky–icy satellites was formed in the outer regions of the gas–dust circumsolar nebula, and its closest analogue currently accessible to study is cometary material. The paper presents a review of experimental data on the chemical and isotopic composition of cometary material as possible sources of volatile components on Titan and Enceladus and model evaluations of temperatures in the circumsolar gas–dust protoplanetary disk and Jupiter’s and Saturn’s protosatellite disks during various evolutionary episodes of the solar system. The P–T parameters of the origin of the protomaterial of Jupiter’s and Saturn’s regular satellites were proved to have been remarkably different, and hence, the material of Europa, a Jupiter’s regular satellite, cannot contain any volatile components other than water, in contrast to Titan and Enceladus. This conclusion is supported by experimental data. Cometary material is likely genetically related to the material of Saturn’s regular satellites Titan and Enceladus. The paper presents results of thermodynamic simulation of the evolution of the chemical and phase composition of Saturn’s satellites and suggests a model for the origin of Titan’s nitrogen–methane atmosphere. 相似文献
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M. Yu. Reshetnyak 《Astronomy Reports》2010,54(11):1047-1052
The effects of a time lag in the magnetic quenching of the α effect is considered for an oscillating magnetic field in a Parker dynamo. The hypothesis of a parametric resonance in the
system is justified, a modification of the solution is found, and the appearance of processes with periods much longer than
the fundamental oscillation period is demonstrated. 相似文献
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A New Zealand Landslide Database has been developed to hold all of New Zealand’s landslide data and provide factual data for use in landslide hazard and risk assessment, including a probabilistic landslide hazard model for New Zealand, which is currently being developed by GNS Science. Design of a national Landslide Database for New Zealand required consideration of existing landslide data stored in a variety of digital formats and future data yet to be collected. Pre-existing landslide datasets were developed and populated with data reflecting the needs of the landslide or hazard project, and the database structures of the time. Bringing these data into a single database required a new structure capable of containing landslide information at a variety of scales and accuracy, with many different attributes. A unified data model was developed to enable the landslide database to be a repository for New Zealand landslides, irrespective of scale and method of capture. Along with landslide locations, the database may contain information on the timing of landslide events, the type of landslide, the triggering event, volume and area data, and impacts (consequences) for each landslide when this information is available. Information from contributing datasets include a variety of sources including aerial photograph interpretation, field reconnaissance and media accounts. There are currently 22,575 landslide records in the database that include point locations, polygons of landslide source and deposit areas, and linear landslide features. Access to all landslide data is provided with a web application accessible via the Internet. This web application has been developed in-house and is based on open-source software such as the underlying relational database (PostGIS) and the map generating Web Map Server (GeoServer). Future work is to develop automated data-upload routines and mobile applications to allow people to report landslides, adopting a consistent framework. 相似文献
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Luc Barbanson Stanislas Sizaret Olivier Rozembaum Jean Louis Rouet 《Mathematical Geosciences》2009,41(8):855-868
A solid can be regarded as a set of contiguous elementary units. The distribution within the solid of any properties, measurable
within each elementary unit, can be characterized using two parameters. These parameters are built using the constitution
and distribution heterogeneities of Gy. The former account for the granularity of the elementary units, whereas the latter
assess the spatial distribution of the property. A texture which definition involves several properties can be described using
a diagram where both parameters work as variables. Potential applications encompass (i) the textural classification of soils,
ore, breccia, and concrete and (ii) the monitoring of textural transformation during process like dolomitization, metamorphism,
weathering, deformation, or annealing. 相似文献
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Simpson’s Paradox in Natural Resource Evaluation 总被引：2，自引：2，他引：0
Y. Zee Ma 《Mathematical Geosciences》2009,41(2):193-213
Reversals of statistical relationships, when two or more groups of data in a cross tabulation are aggregated, were first revealed more than a century ago. The reversal was later named Simpson’s paradox after his reversal examples in a seminal paper drew the attention of the statistical community. However, almost all the published cases have been in sociology and biomedical statistics. Does Simpson’s reversal occur in geosciences? Various examples from petroleum geology and reservoir modeling will be shown in this paper. Boundary conditions for such a reversal will be discussed under a broader framework of sampling analysis. Ecological inference bias, change of support problem, modifiable areal unit problem, and reference class problem will be discussed in relation to the Simpson’s paradox in the framework of spatial statistics. It will be demonstrated that the traditional interpretation of the paradox as a result of disproportional sampling based on a contingency table is not always true in the framework of spatial statistics, and the reversal while theoretically benign is inferentially treacherous. Therefore, emphasis will be on the discussion of combining statistical and scientific inferences in geologic modeling and hydrocarbon resource evaluation under various sampling schemes or support effect with or without a Simpson’s reversal. 相似文献
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Abraham Akkerman 《GeoJournal》2013,78(4):727-741
In the early twentieth century Walter Benjamin introduced the idea of epochal and ongoing progression in interaction between mind and the built environment. Since early antiquity, the present study suggests, Benjamin’s notion has been manifest in metaphors of gender in city-form, whereby edifices and urban voids have represented masculinity and femininity, respectively. At the onset of interaction between mind and the built environment are prehistoric myths related to the human body and to the sky. During antiquity gender projection can be detected in western perceptions linking natural and built environments, commencing with Plato’s Atlantis and his Myth of Er, and later as a likely import of the Chinese yin-yang mythology. Culminating with the Age of Discovery, alongside advances in experiential awareness of the Earth’s sphericity, respective feminine and masculine earmarks can be detected in early modern perspicacity of the Earth’s southern and northern hemispheres. Our conceptions of natural and built environments inherently continue to contain gender traits. Yet urban voids, as the feminine face of city-form, have been severely understated in the built environment. Through design and configuration of urban voids, allegories of femininity in city-form ought to be celebrated, not discarded. 相似文献
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Doklady Earth Sciences - The influence of the compressibility and sphericity of the mantle on the temperature distribution in various models of mantle convection is analyzed. A model providing a... 相似文献
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《Geochimica et cosmochimica acta》1999,63(23-24):3937
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Geology of Ore Deposits - The distribution of major gold deposits in the Earth’s history is discussed. The primary heterogeneity of the Archean crust in terms of gold mineralization is... 相似文献
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Felix V. Kaminsky 《Geochemistry International》2018,56(12):1117-1134
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<正>It is estimated that the world has discovered more than1000 species and 800 genera of dinosaurs.Chinese scientists have named more than 170 species of dinosaurs,with 17 genera and 44 species of dinosaur egg fossils,35genera and 39 species of dinosaur footprints,since their first discovery in China in 1902.China has dinosaur occurrences from the Upper Triassic to the Upper 相似文献