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Acta Geotechnica - Rock-filled gabions are commonly installed in front of reinforced concrete structures to reduce concentrated impact loads induced by rock fall and boulders entrained in debris... 相似文献
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The organic analysis of the murchison meteorite 总被引:1,自引:0,他引:1
The organic compounds released from the Murchison carbonaceous chondrite following vaporization-pyrolysis at 150, 300 and 430°C were investigated. The total organic yield was 272 ppm and consisted of n-alkanes, alkenes, aromatic hydrocarbons and thioaromatics. The composition and yield at all three temperatures are compared with those obtained by an identical analysis on another carbonaceous chondrite, Allende, and two terrestrial rocks.Comparison of compounds released by 150°C volatilization of Murchison and Allende reveals remarkable similarities, suggesting commonality in the processes responsible for their formation. The origin of the organic compounds found can be explained in terms of the Fischer-Tropsch synthesis followed by partial equilibration of the primary products. However, problems concerning the relationship between types of carbonaceous chondrites remain unresolved. 相似文献
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Geologic relationships in the central Pyrenees of southern France demonstrate that lherzolite has been emplaced, as a plastic solid, into middle or upper Cretaceous calcareous rocks; that it has been eroded and clastic peridotite debris deposited in rocks of approximately the same age as those it intruded; and that it has also been juxtaposed against Cretaceous limestone or marble along or within the North Pyrenean fault zone. There are at least three types of late Cretaceous lherzolite breccias known from this region.Metamorphism of the country rock and penetrative deformation of the lherzolite and marble took place during shearing. Shearing was accompanied by an important period of motion (perhaps 85–100 m.y. ago) along the North Pyrenean fault and an associated thermal event which involved temperatures of 400 ± 100°C. Cretaceous metamorphism along the North Pyrenean fault zone was not due to forcible primary hot intrusion of lherzolite. 相似文献
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Farn Parungo Clarence Nagamoto Cecilia M. I. R. Girz Jeff Torgerson Zhou Mingyu 《海洋学报(英文版)》1995,14(2):201-207
ObservationofcloudsandsolarradiationoverthePacificOceanasrelationtoglobalclimate¥FarnParungo;ClarenceNagamoto;CeciliaM.I.R.Gi... 相似文献
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Wang Lingping Song Dongri Zhou Gordon G. D. Chen Xiao Qing Xu Min Choi Clarence E. Peng Peng 《Landslides》2022,19(8):1881-1896
Landslides - The multiple-barrier mitigation strategy in the debris-flow source area is an effective approach to inhibit debris-flow entrainment and scale amplification along the flow path.... 相似文献
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The signal measured by heave–pitch–roll directional wave buoys yields the first four coefficients of a Fourier series. Data adaptive methods must be employed to estimate a directional wave spectrum. Marine X-band radars (MRs) have the advantage over buoys that they can measure “model-free” two-dimensional (2D) wave spectra. This study presents the first comprehensive validation of MR-derived multi-directional wave characteristics. It is based on wave data from the 2010 Impact of Typhoons on the Ocean in the Pacific (ITOP) experiment in the Philippine Sea, namely MR measurements from R/V Roger Revelle, Extreme Air–Sea Interaction (EASI) buoy measurements, as well as WAVEWATCH-III (WW3) modeling results. Buoy measurements of mean direction and spreading as function of frequency, which do not require data adaptive methods, are used to validate the WW3 wave spectra. An advanced MR wave retrieval technique is introduced that addresses various shortcomings of existing methods. Spectral partitioning techniques, applied to MR and WW3 results, reveal that multimodal seas are frequently present. Both data sets are in excellent agreement, tracking the evolution of up to 4 simultaneous wave systems over extended time periods. This study demonstrates MR’s and WW3’s strength at measuring and predicting 2D wave spectra in swell-dominated seas. 相似文献
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An ecosystem-based approach for Alaska groundfish fisheries 总被引:4,自引:2,他引:2
Witherell David; Pautzke Clarence; Fluharty David 《ICES Journal of Marine Science》2000,57(3):771-777
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Acta Geotechnica - Granular impact—the dynamic intrusion of solid objects into granular media—is widespread across scientific and engineering applications including geotechnics.... 相似文献
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Aerosol samples, collected daily were analyzed with electron microscopy for particle concentration and size distribution. The chemical compositions of individual particles were determined with X-ray energy spectrometry and specific morphological tests. The results demonstrated clear and significant dependencies of aerosol properties on air trajectories computed from a backtrack model. Air parcels, such as American air pollution and Sahara dust, were identified. Their physical mixing and chemical reactions with marine aerosols as well as aerosol wet deposition are discussed. 相似文献