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排序方式: 共有211条查询结果,搜索用时 31 毫秒
1.
Philipp R. Heck Christopher Herd Jeffrey N. Grossman Dmitry Badjukov Audrey Bouvier Emma Bullock Hasnaa Chennaoui‐Aoudjehane Vinciane Debaille Tasha L. Dunn Denton S. Ebel Ludovic Ferrire Laurence Garvie Jrme Gattacceca Matthieu Gounelle Richard Herd Trevor Ireland Emmanuel Jacquet Robert J. Macke Tim McCoy Francis M. McCubbin Takashi Mikouchi Knut Metzler Mathieu Roskosz Caroline Smith Meenakshi Wadhwa Linda Welzenbach‐Fries Toru Yada Akira Yamaguchi Ryan A. Zeigler Michael Zolensky 《Meteoritics & planetary science》2019,54(7):1397-1400
2.
Katharina Marger Matthieu Harlaux Andrea Rielli Lukas P. Baumgartner Andrea Dini Barbara L. Dutrow Anne‐Sophie Bouvier 《Geostandards and Geoanalytical Research》2020,44(3):593-615
Six tourmaline samples were investigated as potential reference materials (RMs) for boron isotope measurement by secondary ion mass spectrometry (SIMS). The tourmaline samples are chemically homogeneous and cover a compositional range of tourmaline supergroup minerals (primarily Fe, Mg and Li end‐members). Additionally, they have homogeneous boron delta values with intermediate precision values during SIMS analyses of less than 0.6‰ (2s). These samples were compared with four established tourmaline RMs, that is, schorl IAEA‐B‐4 and three Harvard tourmalines (schorl HS#112566, dravite HS#108796 and elbaite HS#98144). They were re‐evaluated for their major element and boron delta values using the same measurement procedure as the new tourmaline samples investigated. A discrepancy of about 1.5‰ in δ11B was found between the previously published reference values for established RMs and the values determined in this study. Significant instrumental mass fractionation (IMF) of up to 8‰ in δ11B was observed for schorl–dravite–elbaite solid solutions during SIMS analysis. Using the new reference values determined in this study, the IMF of the ten tourmaline samples can be modelled by a linear combination of the chemical parameters FeO + MnO, SiO2 and F. The new tourmaline RMs, together with the four established RMs, extend the boron isotope analysis of tourmaline towards the Mg‐ and Al‐rich compositional range. Consequently, the in situ boron isotope ratio of many natural tourmalines can now be determined with an uncertainty of less than 0.8‰ (2s). 相似文献
3.
Although meteorites are now considered as scientific objects, they still bear a strong and powerful symbolic meaning due to their extraterrestrial provenance. The present article focuses on their legal status, in other words the collection of rules, very diverse in nature, which are applicable to them. Despite a growing international market, the question of meteorites is often ignored or regarded as a detail in international relations and is rarely taken explicitly into account in negotiations and treaties. This relative neglect explains why a non‐State player, the Meteoritical Society, has taken methodological initiatives into meteoritic science and has effectively become a regulator of meteorite naming and acceptance, with a global scope. We show that to understand the legal status of meteorites, it is necessary to consider them under the prism of public international law, transnational law, and national law. We conclude that, despite the universality of meteorites as extraterrestrial objects, the variability of legal rules applicable to meteorites depending onto which territory they fall or where they are found. We note, however, that there is a trend toward regulatory uniformity in the scientific analysis of meteorites, which frames the practices of researchers and regulates traders’ activities. Finally, we contend that a meteorite remains a badly defined legal object, because it can be viewed under many angles: as an object susceptible to private appropriation, as a “common thing” (res communis), or as an element of national heritage. 相似文献
4.
5.
A new elastoplastic model called loading memory surface based on the critical state concept and the multi‐surface framework is proposed for geomaterials. The model uses a hypoelastic formulation and two plastic mechanisms. The formulations of the model are made in three‐dimensional stress–strain space and work under both monotonic and cyclic loadings. A newly introduced formalism makes it possible to obtain the cyclic response directly from the monotonic loading one. This formalism gives a three‐dimensional generalization of the well‐known Masing rule. The model has been validated against test results of Hostun sand under several conditions: monotonic and cyclic, drained and undrained, tests in compression and in extension, and at different confining pressures and different densities. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
6.
7.
Jennifer Vandenhecke Matthieu Waeles Jean-Yves Cabon Cédric Garnier Ricardo D. Riso 《Estuarine, Coastal and Shelf Science》2010
Over this one-year study, the variations of inorganic As species were examined monthly along the salinity gradient of the Penzé estuary (NW France) in relation with different biogeochemical parameters. In most cases, dissolved As exhibited a non-conservative behaviour which resulted from the competition between two major processes. In the upstream section of the estuary, a strong input of both total inorganic As and As(III) occurred. Then, the removal of the same species, under precipitation of iron oxides/oxyhydroxides, was observed in the low-salinity range (S < 10). Using our experimental data, the fluxes of the various As species were estimated for the first time in estuarine waters. Inputs from the river were mainly constituted of particulate As (∼70%). Conversely, dissolved species were predominant in the net fluxes (∼65%) and As(III) accounted for ∼15% of the dissolved net flux. 相似文献
8.
Th sorption and export models in the water column: A review 总被引:2,自引:3,他引:2
Nicolas Savoye Claudia Benitez-Nelson Adrian B. Burd J. Kirk Cochran Matthew Charette Ken O. Buesseler George A. Jackson Matthieu Roy-Barman Sabine Schmidt Marc Elskens 《Marine Chemistry》2006,100(3-4):234
Over the past few decades, the radioisotope pair of 238U / 234Th has been widely and increasingly used to describe particle dynamics and particle export fluxes in a variety of aquatic systems. The present paper is one of five review articles dedicated to 234Th. It is focused on the models associated with 234Th whereas the companion papers (same issue) are focused on present and future methodologies and techniques (Rutgers van der Loeff et al.), C / 234Th ratios (Buesseler et al.), 234Th speciation (Santschi et al.) and present and future applications of 234Th [Waples, J.T., Benitez-Nelson, C.R., Savoye, N., Rutgers van der Loeff, M., Baskaran, M., Gustafsson, Ö., this issue. An Introduction to the application and future use of 234Th in aquatic systems. Marine Chemistry, FATE special issue]. In this paper, we review current 234Th scavenging models and discuss the relative importance of the non-steady state and physical terms associated with the most commonly used model to estimate 234Th flux. Based on this discussion we recommend that for future work the use of models should be accompanied by a discussion of the effect that model and data uncertainty have on the model results. We also suggest that future field work incorporate repeat occupations of sample sites on time scales of 1–4 weeks in order to evaluate steady state versus non-steady state estimates of 234Th export, especially during high flux events (> ca. 800 dpm m− 2 d− 1). Finally, knowledge of the physical oceanography of the study area is essential, particularly in ocean margins and in areas of established upwelling (e.g., Equatorial Pacific). These suggestions will greatly enhance the application of 234Th as a tracer of particle dynamics and flux in more complicated regimes. 相似文献
9.
10.
Stability analysis of the 2007 Chehalis lake landslide based on long-range terrestrial photogrammetry and airborne LiDAR data 总被引:1,自引:1,他引:0
Marc-André Brideau Matthieu Sturzenegger Doug Stead Michel Jaboyedoff Martin Lawrence Nicholas J. Roberts Brent C. Ward Thomas H. Millard John J. Clague 《Landslides》2012,9(1):75-91
On December 4th 2007, a 3-Mm3 landslide occurred along the northwestern shore of Chehalis Lake. The initiation zone is located at the intersection of the
main valley slope and the northern sidewall of a prominent gully. The slope failure caused a displacement wave that ran up
to 38 m on the opposite shore of the lake. The landslide is temporally associated with a rain-on-snow meteorological event
which is thought to have triggered it. This paper describes the Chehalis Lake landslide and presents a comparison of discontinuity
orientation datasets obtained using three techniques: field measurements, terrestrial photogrammetric 3D models and an airborne
LiDAR digital elevation model to describe the orientation and characteristics of the five discontinuity sets present. The
discontinuity orientation data are used to perform kinematic, surface wedge limit equilibrium and three-dimensional distinct
element analyses. The kinematic and surface wedge analyses suggest that the location of the slope failure (intersection of
the valley slope and a gully wall) has facilitated the development of the unstable rock mass which initiated as a planar sliding
failure. Results from the three-dimensional distinct element analyses suggest that the presence, orientation and high persistence
of a discontinuity set dipping obliquely to the slope were critical to the development of the landslide and led to a failure
mechanism dominated by planar sliding. The three-dimensional distinct element modelling also suggests that the presence of
a steeply dipping discontinuity set striking perpendicular to the slope and associated with a fault exerted a significant
control on the volume and extent of the failed rock mass but not on the overall stability of the slope. 相似文献