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71.
Aur��lien Bideaud Benoit Belier Alain Benoit Laurent Berg�� Philippe Camus Sophie Collin Louis Dumoulin Christian Hoffmann Stefanos Marnieros Alessandro Monfardini 《Experimental Astronomy》2011,32(2):179-191
Microbolometers are at present the most sensitive detectors for mm and sub-mm Astronomy. They are in use in most of the present instruments in that bandwidth. We have developed filled arrays of NbSi-based planar antenna coupled microbolometers. The fabrication details are given, together with characterization of the NbSi thermometers and optical results. The optical performances are potentially good for ground-based mm-wave astronomy applications, while the overall detectors performances are limited by low-frequency excess noise in the thermometric NbSi high-impedance sensors (Anderson insulator). 相似文献
72.
We present a method to transform the governing equations of multispecies reactive transport in porous media. The reformulation leads to a smaller problem size by decoupling of equations and by elimination of unknowns, which increases the efficiency of numerical simulations. The reformulation presented here is a generalization of earlier works. In fact, a whole class of transformations is now presented. This class is parametrized by the choice of certain transformation matrices. For specific choices, some known formulations of reactive transport can be retrieved. Hence, the software based on the presented transformation can be used to obtain efficiency comparisons of different solution approaches. For our efficiency tests, we use the MoMaS benchmark problem on reactive transport. 相似文献
73.
A 1,460-m-long profile of a Late Glacial subglacial, glacio-fluvial, glacio-limnic and glacio-deltaic sequence exposed at
a cliff section on Usedom Island (SW Baltic Sea coast) is described. The sequence is up to 31 m thick and shows sedimentary
structures typical of a glacial setting. Soft-sediment deformation is encountered and is associated with changes in lithology.
These deformations include liquefaction, slumping, and faulting. As the most plausible cause, earthquake-induced shaking is
discussed. The associated neotectonic activity is seen as a consequence of the postglacial isostatic crustal rebound. As the
deglaciation earthquake ratio diminishes with time and as the rebound is phasing out, no large earthquakes are anticipated
for northern Germany, although in conclusion the lithosphere of the North German Basin has to be regarded as weakened by repeated
ice loading and deloading. 相似文献
74.
Nadine Hoffmann Klaus Reicherter Christoph Grützner Jochen Hürtgen Andreas Rudersdorf Finn A. Viehberg Martin Wessels 《Central European Journal of Geosciences》2012,4(1):94-110
Lake Ohrid (between FYR of Macedonia and Albania), situated in an active tectonic region of the Balkanides, is characterized by N ?? S trending active faults. To reconstruct the Holocene shoreline evolution we investigated the coastline using sediment cores and geophysical methods to image sedimentary and tectonic structures. We revealed areas of differing sedimentation regimes. The plains north and south of the lake are dominated by clastic input related to climate variations and uplift/erosion, whereas the steep western and eastern margins are controlled by recent tectonics. Furthermore, no evidence for a much higher lake-level during the Holocene was found in the plains north and south of the lake, except rare temporary floodings. This is supported by mappings of the limestone cliffs around Lake Ohrid, which yielded no evidence for abrasional platforms or notches as indicators for past highstands. 相似文献
75.
J. Bremer P. Hoffmann R. Latteck W. Singer M. Zecha 《Journal of Atmospheric and Solar》2009,71(14-15):1571-1576
Strong VHF radar echoes have been observed not only during summer months at polar latitudes (polar mesosphere summer echoes, PMSE) but also at middle latitudes (mesosphere summer echoes, MSE). These echoes are closely connected with small ice particles, thus containing information about mesospheric temperature and water vapour content. But the (P)MSE also depend on the ionisation due to solar wave radiation and precipitating high energetic particles. Observations with VHF radars at Andenes (69.3°N; 16.0°E) since 1994 and at Kühlungsborn (54.6°N; 11.8°E) since 1998 are used for investigations of the solar and geomagnetic control of the (P)MSE as well as of possible long-term changes. The (P)MSE are positively correlated with the solar Lyman α radiation and the geomagnetic activity and have slightly positive trends. Due to the limited measuring period, the significance levels of the detected (P)MSE trends are small. Positive trends in noctilucent clouds (NLC) and polar mesospheric clouds (PMC) are in general agreement with (P)MSE trends. 相似文献
76.
Diana Jordanova Petar Petrov Viktor Hoffmann Tilman Gocht Cristian Panaiotu Tsenka Tsacheva Neli Jordanova 《Studia Geophysica et Geodaetica》2010,54(3):417-442
Detailed magnetic study on vegetation samples from several strongly polluted and clean sites in Bulgaria is carried out in
order to evaluate suitability of different species as passive dust collectors in magnetometry. From each location, available
species among lichens, mosses, poplar leaves, dandelion, needles have been sampled. Magnetic susceptibility calculated on
mass-specific basis shows wide variability between diamagnetic signal up to 846 × 10−8 m3/kg. Lichens and mosses are found to be the species, showing magnetic signals with the strongest contrast between clean and
polluted environment. The main magnetic phase is magnetite-like according to the results from thermomagnetic analysis of susceptibility
on magnetic extracts. Scanning electron microscopy (SEM) microphotographs reveal the presence of abundant particulate matter
on vegetation surface both with anthropogenic (spherules) and lithogenic origin. Magnetic grain size deduced by the ratio
of saturation remanent magnetization (SIRM) and mass-specific magnetic susceptibility (χ) and coercivities (Bc and Bcr) suggest that different species accumulate preferentially small SD-like grains from pollution emissions. Contrasting relationship
of the ratio of anhysteretic remanent magnetization (ARM) and χ for polluted vs clean sites deduced by needles and lichens
may be related to transformation of the accumulated dust particles within lichens’ tissue. This finding indicates that the
exact species used as biological dust collector is of importance when studying spatial grain size distribution of magnetic
dust particles. Pilot study on polycyclic aromatic hydrocarbons (PAH) content and its relation to magnetic parameters shows
good correspondence between high levels of PAHs and high SIRM values for locations affected by non-ferrous industrial production. 相似文献
77.
78.
对取自首都钢铁厂附近的土壤样芯进行了重金属含量、形态分析和的磁学测量.探讨了利用磁参数追踪和指示重金属污染和有机结合态和铁锰氧化结合态重金属的可行性.结果表明:土壤样芯中Cu、Pb、Zn、Fe和Mn的含量与χ、SIRM和ARM存在着十分相似的垂向变化特征,且相关关系显著(0.98>R>0.86).进一步对磁化率和Cu、Pb、Zn、Fe和Mn各结合态进行相关分析表明:五种元素的有机结合态与铁锰结合态和磁化率呈显著相关关系(0.98>R>0.56),而交换态和残渣态重金属与磁化率基本不存在相关关系.反映了磁性矿物和和重金属在赋存状态的本质联系.表明了磁性测量可作为工业区土壤重金属污染及有机结合态与铁锰结合态重金属记录信息提取的辅助手段. 相似文献
79.
R. Friedrich B. Wickert P. Blank S. Emeis W. Engewald D. Hassel H. Hoffmann H. Michael A. Obermeier K. Schäfer T. Schmitz A. Sedlmaier M. Stockhause J. Theloke F.-J. Weber 《Journal of Atmospheric Chemistry》2002,42(1):179-206
Measurements and model developments with the objective to improve the quality and resolution of estimations of anthropogenic emissions are described. Measurement results on a chassis dynamometer were used to determine VOC profiles for exhaust gas emissions of passenger cars for different vehicle and fuel types and different driving modes. Further measurements resulted in emission factors and VOC profiles for lignite burning in residential stoves. Using remote sensing techniques benzene emission factors of gas stations and the efficiency of gasoline vapour recovery systems were measured.To improve the quality and the spatial and temporal resolution of emission data, emission models were improved or modified. This was done by elaborating and applying new methods for important emission source categories (e.g., solvent use, road traffic, small combustion) as well as including new data sources in the calculation routines (e.g. emission statements, land use data, import/export indices of solvents). Simultaneously considerable progress was made improving temporal and spatial allocation functions and VOC profiles. With these improvements a large number of anthropogenic emission data sets for 14 different grid projections in Germany and Europe have been generated. An emission scenario for Germany for 2010 suggests that considering air quality directives from the EU and Germany which are in force or in pipeline, German emissions of VOC and NOx will decrease, but still exceed the national emission ceilings of the EU-NEC directive. 相似文献
80.
An Inter-Laboratory Assessment of the Thorium Isotopic Composition of Synthetic and Rock Reference Materials 总被引:2,自引:0,他引:2
Kenneth W.W. Sims James B. Gill Anthony Dosseto Dirk L. Hoffmann Craig C. Lundstrom Ross W. Williams Lary Ball Darren Tollstrup Simon Turner Julie Prytulak Justin J.G. Glessner J.J. Standish Tim Elliott 《Geostandards and Geoanalytical Research》2008,32(1):65-91
We present a concerted international effort to cross-calibrate five synthetic Th isotope reference materials (UCSC Th "A", OU Th "U", WUN, IRMM-35 and IRMM-36), and six rock reference materials (UCSC TML, Icelandic ATHO, USGS BCR-2, USGS W-2, USGS BHVO-2, LV18) using multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS). We then compare our new values with a compilation of literature mass spectrometric data for these reference materials and derive recommended "consensus"230 Th/232 Th values for each. We also present isotope dilution U and Th concentration data for four rock reference materials (UCSC TML, Icelandic ATHO, USGS BCR-2, USGS W-2). 相似文献