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排序方式: 共有390条查询结果,搜索用时 31 毫秒
331.
Juraj Tóth Ján Svoreň Jiří Borovička Pavel Spurný Antal Igaz Leonard Kornoš Peter Vereš Marek Husárik Július Koza Aleš Kučera Pavel Zigo Štefan Gajdoš Jozef Világi David Čapek Zuzana Krišandová Dušan Tomko Jiří Šilha Eva Schunová Marcela Bodnárová Diana Búzová Tereza Krejčová 《Meteoritics & planetary science》2015,50(5):853-863
We provide the circumstances and details of the fireball observation, search expeditions, recovery, strewn field, and physical characteristics of the Ko?ice meteorite that fell in Slovakia on February 28, 2010. The meteorite was only the 15th case of an observed bolide with a recovered mass and subsequent orbit determination. Despite multiple eyewitness reports of the bolide, only three videos from security cameras in Hungary were used for the strewn field determination and orbit computation. Multiple expeditions of professionals and individual searchers found 218 fragments with total weight of 11.3 kg. The strewn field with the size of 5 × 3 km is characterized with respect to the space distribution of the fragments, their mass and size‐frequency distribution. This work describes a catalog of 78 fragments, mass, size, volume, fusion crust, names of discoverers, geographic location, and time of discovery, which represents the most complex study of a fresh meteorite fall. From the analytical results, we classified the Ko?ice meteorite as an ordinary H5 chondrite. 相似文献
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Martin Pätzold Matthias Hahn Silvia Tellmann Bernd Häusler Michael K. Bird G. Leonard Tyler Sami W. Asmar Bruce T. Tsurutani 《Solar physics》2012,279(1):127-152
Coronal radio-sounding experiments were carried out using the S-band (2.3 GHz) and X-band (8.4 GHz) signals of the ESA Mars Express, Venus Express, and Rosetta spacecraft during five superior conjunctions occurring in 2004, 2006 (3×), and 2008/2009. Differential frequency and propagation delay (ranging) observations were recorded during these opportunities over the better part of a solar cycle, yielding information on the large-scale structure of the coronal electron-density distribution and its variations, including fluctuations on time scales from seconds to hours. These results concern primarily regions of slow solar wind because the radio propagation path is generally confined to the low heliolatitude regions by the conjunction. The mean frequency fluctuation and total electron content are determined as a function of heliocentric distance, and, with a few exceptions caused by streamers and CMEs, are found to be consistent with previous results from experiments on Ulysses. Dense coronal streamers and several coronal mass ejection (CME) events were identified in the radio-frequency data, some of which were observed in white light by the LASCO coronagraphs onboard SOHO. For those events with sufficient mutual coverage, good correlations are found between the electron-content fluctuations and structure imaged by the LASCO instrument. 相似文献
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Leonard Boszke Artur Kowalski Aleksander Astel Andrzej Barański Barbara Gworek Jerzy Siepak 《Environmental Geology》2008,55(5):1075-1087
The mobility and bioavailability of mercury in the soil from the area near a plant using elemental mercury for manufacturing
thermometers, areometers, glass energy switches and other articles made of technical glass has been evaluated. Mercury has
been determined by sequential extraction method and with additional thermo desorption stage to determine elemental mercury.
The procedure of sequential extraction involves five subsequent stages performed with the solutions of chloroform, deionized
water, 0.5 M HCl, 0.2 M NaOH and aqua regia. The mean concentration of total mercury in soil was 147 ± 107 μg g−1 dry mass (range 62–393), and the fractionation revealed that mercury was mainly bound to sulfides 56 ± 8% (range 45–66),
one of the most biounavailable and immobile species of mercury in the environment. The fractions that brought lower contribution
to the total mercury content were semi-mobile humic matter 22 ± 9% (range 11–34) and elemental mercury 17 ± 5% (range 8–23).
The contributions brought by the highly mobile and toxic organomercury compounds were still lower 2.3 ± 2.7% (range 0.01–6.5).
The lowest contributions brought the acid-soluble mercury 1.5 ± 1.3% (range 0.1–3.5) and water-soluble mercury 1.0 ± 0.3%
(range 0.6–1.7). The surface layer of soil (0–20 cm) was characterized by higher mercury concentrations than that of the subsurface
soil (60–80 cm), but the fractional contributions were comparable. The comparison of mercury fractionation results obtained
in this study for highly polluted soils with results of fractionation of uncontaminated or moderately contaminated samples
of soil and sediments had not shown significant statistical differences; however, in the last samples elemental mercury is
usually present at very low concentrations. On the basis of obtained correlation coefficients it seems that elemental mercury
soils from “Areometer” plant are contaminated; the main transformation is its vaporization to atmosphere and oxidation to
divalent mercury, probably mainly mediated by organic matter, and next bound to humic matter and sulfides. 相似文献
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Rachel Bynoe Nick M. Ashton Tim Grimmer Peter Hoare Joanne Leonard Simon G. Lewis Darren Nicholas Simon Parfitt 《第四纪科学杂志》2021,36(2):191-210
Recent archaeological discoveries from exposures of the Cromer Forest-bed Formation at Happisburgh, UK, have radically changed interpretations of the nature and timing of early hominin occupation of northern latitudes, but this in situ archaeology is only one part of the picture. Surface finds of Pleistocene mammalian remains have been found along this coastline for centuries, with stone tools adding to this record over the past 7 years. The ex situ nature of these finds, however, means they are often seen as limited in the information they can provide. This work contributes to a growing body of research from a range of landscape and environmental contexts that seeks to demonstrate the value and importance of these ex situ assemblages. Here the focus is on Palaeolithic flint artefacts and Pleistocene mammalian remains recovered by a group of local collectors through systematic, GPS-recorded beach collection from 2013 to 2017, and their use in developing a methodology for working with ex situ Palaeolithic finds in coastal locations. The results demonstrate significant patterning that identifies unexplored exposures both onshore and offshore, considerably expanding the known extent of deposits and facilitating new insights into the wider archaeological landscape associated with the earliest occupation of northern Europe. 相似文献
340.
Sonia Leonard Meg Parsons Knut Olawsky Frances Kofod 《Global Environmental Change》2013,23(3):623-632
Indigenous peoples offer alternative knowledge about climate variability and change based on their own locally developed knowledges and practices of resource use. In this article we discuss the role of traditional ecological knowledge in monitoring and adapting to changing environmental conditions. Our case study documents a project to record the seasonal knowledge of the Miriwoong people in northern Australia. The study demonstrates how indigenous groups’ accumulate detailed baseline information about their environment to guide their resource use and management, and develop worldviews and cultural values associated with this knowledge. We highlight how traditional ecological knowledge plays a critical role in mediating indigenous individuals and communities’ understandings of environmental changes in the East Kimberley region of north-west Australia, and how these beliefs may influence future decision-making about how to go about adapting to climate change at a local level. 相似文献