Distribution,speciation, and budget of atmospheric mercury   总被引：9，自引：0，他引：9  

F. Slemr  G. Schuster  W. Seiler 《Journal of Atmospheric Chemistry》1985,3(4):407-434

Total gaseous mercury (TGM) concentrations over the Atlantic Ocean and over Central Europe were measured repeatedly in the years 1978–1981. The latitudinal TGM distribution showed a pronounced and reproducible interhemispherical difference with higher TGM concentrations in the Northern Hemisphere. TGM was found to be vertically well mixed within the troposphere. The TGM concentration seems to increase with time at a rate of 10±8%/yr in the Northern and 8±3%/yr in the Southern Hemisphere. Measurements of mercury speciation showed that elemental mercury is the main TGM component contributing more than 92% and 83% of TGM in marine and continental air, respectively. The tropospheric mercury burden was calculated to be 6×10⁹g. The interhemispheric distribution and temporal and spatial variability of TGM imply a tropospheric residence time of TGM of about 1 yr. Sink strengths calculated independently from the measured mercury concentration on particles and in rainwater are consistent with the above figures.  相似文献   

Erfahrungen auf dem Gebiet der Entölung von Kraftwerksabwässern     

H. Schuster 《洁净——土壤、空气、水》1980,8(5):473-483

Je nach Brennstoffbasis und Technologie der Kraftwerke entstehen Abwässer mit unterschiedlichen Mengen und verschiedenen Konzentrationen an Öl und Feststoffen. Hiernach orientieren sich der Umfang und die Methoden der Emulsionsbrechung, Entölung sowie Feststoffabtrennung. Die gegenwärtig üblichen Verfahren werden an mehreren schematischen Darstellungen erläutert. Abschließend werden Vorschläge für künftige Forschungsaufgaben gebracht, wobei der Schwerpunkt der Untersuchungen auf die Wiedergewinnung von Wertstoffen wie Öl, Vanadinpentoxid u. a. zu orientieren ist. Durch wasserwirtschaftliche Prozeßanalysen in den Kraftwerken sind Ansatzpunkte zur Intensivierung bzw. Rationalisierung vorhandener oder neuartiger Technologien zu entwickeln.  相似文献   

Interferometric interpolation of sparse marine data     

Sherif M. Hanafy  Gerard T. Schuster 《Geophysical Prospecting》2014,62(1):1-16

We present the theory and numerical results for interferometrically interpolating 2D and 3D marine surface seismic profiles data. For the interpolation of seismic data we use the combination of a recorded Green's function and a model‐based Green's function for a water‐layer model. Synthetic (2D and 3D) and field (2D) results show that the seismic data with sparse receiver intervals can be accurately interpolated to smaller intervals using multiples in the data. An up‐ and downgoing separation of both recorded and model‐based Green's functions can help in minimizing artefacts in a virtual shot gather. If the up‐ and downgoing separation is not possible, noticeable artefacts will be generated in the virtual shot gather. As a partial remedy we iteratively use a non‐stationary 1D multi‐channel matching filter with the interpolated data. Results suggest that a sparse marine seismic survey can yield more information about reflectors if traces are interpolated by interferometry. Comparing our results to those of f‐k interpolation shows that the synthetic example gives comparable results while the field example shows better interpolation quality for the interferometric method.  相似文献   

Submillimeter CO spectroscopy of low mass young stellar objects     

K. -F. Schuster  A. P. G. Russell  A. I. Harris 《Astrophysics and Space Science》1995,224(1-2):117-120

We report submillimeter CO(6-5) observations around 15 nearby young stellar objects of low mass. The correlation between linewidth and peak temperature indicates shock heating of dense gas, presumably at the origin of molecular outflows.  相似文献   

美国西部滑坡坝的合作研究   总被引：1，自引：0，他引：1  

李天池  吴积善  R.L.舒斯特 《山地学报》1988,(4)

沟谷的滑坡成坝已成为美国西部山地中一个值得注意的问题。1985年作者们考察了美国西部六州九个滑坡坝的特点。这是执行1979年中美科学技术合作协议(特别是1980年地学合作补充议定书)的部分内容。中美两国科学家和工程专家考察九个滑坡坝后,取得了一些研究成果,即论述了滑坡坝(尤其是近代滑坡坝)的成因与稳定性,并列举了灾变性溃坝防止措施的若干成功经验。  相似文献   

Reply to Comment by W. Kurz on “Tectonic map and overall architecture of the Alpine orogen”     

Stefan M. Schmid  Bernhard Fügenschuh  Eduard Kissling  Ralf Schuster 《Eclogae Geologicae Helvetiae》2005,98(1):99-101

  相似文献   

Migration methods for imaging different-order multiples   总被引：2，自引：0，他引：2  

Zhiyong Jiang  Jianming Sheng  Jianhua Yu  Gerard T. Schuster  Brian E. Hornby 《Geophysical Prospecting》2007,55(1):1-19

Multiples contain valuable information about the subsurface, and if properly migrated can provide a wider illumination of the subsurface compared to imaging with VSP primary reflections. In this paper we review three different methods for migrating multiples. The first method is model-based, and it is more sensitive to velocity errors than primary migration; the second method uses a semi-natural Green's function for migrating multiples, where part of the traveltimes are computed from the velocity model, and part of the traveltimes (i.e., natural traveltimes) are picked from the data to construct the imaging condition for multiples; the third method uses cross-correlation of traces. The last two methods are preferred in the sense that they are significantly less sensitive to velocity errors and statics because they use “natural data” to construct part of the migration imaging conditions. Compared with the interferometric (i.e., crosscorrelation) imaging method the semi-natural Green's function method is more computationally efficient and is sometimes less prone to migration artifacts. Numerical tests with 2-D and 3-D VSP data show that a wider subsurface coverage, higher-fold and more balanced illumination of the subsurface can be achieved with multiple migration compared with migration of primary reflections only. However, there can be strong interference from multiples with different orders or primaries when multiples of high order are migrated. One possible solution is to filter primaries and different orders of multiples before migration, and another possible solution is least squares migration of all events. A limitation of multiple migration is encountered for subsalt imaging. Here, the multiples must pass through the salt body more than twice, which amplifies the distortion of the image.  相似文献   

Static elasticity of cordierite II: effect of molecular CO2 channel constituents on the compressibility     

K. S. Scheidl  G. D. Gatta  T. Pippinger  B. Schuster  C. Trautmann  R. Miletich 《Physics and Chemistry of Minerals》2014,41(8):617-631

Two natural CO₂-rich cordierite samples (1.00 wt% CO₂, 0.38 wt% H₂O, and 1.65 wt% CO₂, 0.15 wt% H₂O, respectively) were investigated by means of Raman spectroscopy and single-crystal X-ray diffraction at ambient and high pressures. The effect of heavy-ion irradiation (Au 2.2 GeV, fluence of 1 × 10¹² ions cm^?2) on the crystal structure was investigated to characterize the structural alterations complementary to results reported on hydrous cordierite. The linear CO₂ molecules sustained irradiation-induced breakdown with small CO₂-to-CO conversion rates in contrast to the distinct loss of channel H₂O. The maximum CO₂ depletion rate corresponds to ~12 ± 5 % (i.e. ~0.87 and ~1.49 wt% CO₂ according to the two samples, respectively). The elastic properties of CO₂-rich cordierite reveal stiffening due to the CO₂ molecules (non-irradiated: isothermal bulk modulus K ₀ = 120.3 ± 3.7 GPa, irradiated: K ₀ = 109.7 ± 3.7 GPa), but show the equivalent effect of hydrous cordierite to get softer when irradiated. The degree of anisotropy of axial compressibilities and the anomalous elastic softening at increasing pressure agrees with those reported for hydrous cordierite. Nevertheless, the experimental high-pressure measurements using ethanol–methanol reveal a small hysteresis between compression and decompression, together with the noticeable effect of pressure-induced over-hydration at pressures between 4 and 5 GPa.  相似文献   

Palaeoseismicity of the Oquirrh fault, Utah from shallow seismic tomography     

David Morey  & Gerard T. Schuster 《Geophysical Journal International》1999,138(1):25-35

The magnitude and frequency of normal-fault palaeoearthquakes are usually determined by trenching studies that ascertain the size and number of colluvial wedges along the fault. Such information can be invaluable in predicting the seismic hazard and potential for a future earthquake in that region. Digging trenches across normal faults, however, is environmentally intrusive, expensive and limited in the penetration depth. To overcome these problems we propose the use of 3-D seismic tomography as a means to identify the shapes and sizes of colluvial wedges along normal faults. As an example,2-D and 3-D seismic surveys were conducted across the Oquirrh fault, Utah with the purpose of imaging the normal-fault structure to a depth of about 10  m. Results show that the 3-D tomogram clearly delineates the fault zone and a colluvial wedge, both of which correlate extremely well with the geological cross-section interpreted from an adjacent trench. The thickness of the colluvial wedge image is used in conjunction with a seismic section to compute an estimate of a 6.8 moment magnitude earthquake for the most recent event on this fault, which is in close agreement with the 7.0 estimate based on a nearby trenching study. These tomographic results demonstrate, for the first time, that seismic imaging methods can be used in some cases to estimate unambiguously the shapes of colluvial wedges and the sizes of prehistoric earthquakes. Thus, seismic tomography has the possibility of providing cheaper, deeper and wider, but less resolved, images of fault systems than the intrusive excavation of trenches across faults.  相似文献   

Strömgren 4-Color Photometry of Very Metal-Poor Stars     

W.J. Schuster  L. Parrao  A. Franco  T.C. Beers  P.E. Nissen 《Astrophysics and Space Science》1999,265(1-4):183-184

Strömgren uvby photometry has been observed for an additional 140 very metal-poor stars from the survey of Beers et al. (1992). These Galactic stars of very-low metallicity provide crucial information for the investigation of the formation and evolution of the Galaxy, as well as on the nature of the early Universe. The Strömgren uvby-β system allows the measurement of stellar atmospheric parameters as a prelude to detailed abundance studies which will make use of high-resolution spectroscopy and the new generation of large telescopes. The photometric techniques developed by Schuster et al. (1996) are used not only to classify these very metal-poor stars but also to derive effective temperatures, surface gravities, and improved estimates for their interstellar reddenings. In particular, photometric diagrams such as [c ₁], [m ₁] and c ₀, (b-y)₀ are used to classify these stars, especially those near the main-sequence turnoff, where contamination from slightly-evolved subgiants, lower surface-gravity horizontal-branch stars, and even a few supergiant or AGB candidates is found.  相似文献