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21.
Christian Moeck Dirk Radny Adrian Auckenthaler Michael Berg Juliane Hollender Mario Schirmer 《Isotopes in environmental and health studies》2017,53(5):484-499
Stable isotopes of water, organic micropollutants and hydrochemistry data are powerful tools for identifying different water types in areas where knowledge of the spatial distribution of different groundwater is critical for water resource management. An important question is how the assessments change if only one or a subset of these tracers is used. In this study, we estimate spatial artificial infiltration along an infiltration system with stage–discharge relationships and classify different water types based on the mentioned hydrochemistry data for a drinking water production area in Switzerland. Managed aquifer recharge via surface water that feeds into the aquifer creates a hydraulic barrier between contaminated groundwater and drinking water wells. We systematically compare the information from the aforementioned tracers and illustrate differences in distribution and mixing ratios. Despite uncertainties in the mixing ratios, we found that the overall spatial distribution of artificial infiltration is very similar for all the tracers. The highest infiltration occurred in the eastern part of the infiltration system, whereas infiltration in the western part was the lowest. More balanced infiltration within the infiltration system could cause the elevated groundwater mound to be distributed more evenly, preventing the natural inflow of contaminated groundwater.
Dedicated to Professor Peter Fritz on the occasion of his 80th birthday 相似文献
22.
Ansgar Jüngel José Luis López Jesús Montejo–Gámez 《Journal of statistical physics》2011,145(6):1661-1673
A quantum Navier–Stokes system for the particle, momentum, and energy densities is formally derived from the Wigner–Fokker–Planck
equation using a moment method. The viscosity term depends on the particle density with a shear viscosity coefficient which
equals the quantum diffusion coefficient of the Fokker–Planck collision operator. The main idea of the derivation is the use
of a so-called osmotic momentum operator, which is the sum of the phase-space momentum and the gradient operator. In this
way, a Chapman–Enskog expansion of the Wigner function, which typically leads to viscous approximations, is avoided. Moreover,
we show that the osmotic momentum emerges from local gauge theory. 相似文献
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A novel (to our knowledge) dual-core ytterbium (Yb(3+)) doped fiber, as an optically pumped amplifier, boosts the output power from a 1060 nm swept source laser beyond 250 mW, while providing a wavelength tuning range of 93 nm, for optical coherence tomography (OCT) imaging. The design of the dual-core Yb-doped fiber amplifier and its multiple wavelength optical pumping scheme to optimize output bandwidth are discussed. Use of the dual-core fiber amplifier showed no appreciable degradation to the coherence length of the seed laser. The signal intensity improvement of this amplifier is demonstrated on a multichannel in vivo OCT imaging system at 1060 nm. 相似文献
25.
Elisabeth-Jeanne Popovici Mihail Nazarov Laura Muresan Do Young Noh Marius Morar Ecaterina Bica Emil Indrea 《Radiation measurements》2010,45(3-6):300-303
Terbium activated yttrium niobium tantalate phosphors were prepared by solid-state reaction and were characterized by photoluminescence measurements, X-ray diffraction and scanning electron microscopy. Photoluminescence (PL) of Y0.95Tb0.05Ta1?xNbxO4 phosphors (x = 0–1) are influenced by the host-lattice composition, degree of crystalline order and particle morphology and size. The effect of the morpho-structural properties on PL characteristics of Y(Ta,Nb)O4:Tb powders is reported. 相似文献
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George Stoica 《Comptes Rendus Mathematique》2003,336(2):191-193
We extend the Bovier–Picco–Zhang laws of the iterated logarithm for geometrically weighted random series, and give the rate of convergence towards the limit set. To cite this article: G. Stoica, C. R. Acad. Sci. Paris, Ser. I 336 (2003). 相似文献
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Ronald J. Adrian 《Optics and Lasers in Engineering》1988,9(3-4):211-228
A particle image velocimeter method is described in which double exposed fields of particles moving in a two-dimensional slice of a steady turbulent flow are photographed repeatedly to build up a statistical ensemble of flow field realizations on a single photographic plate. Each interrogation spot on the plate contains a sample of the probability density function of the two components of velocity that lie in the photographic object plane, assuming paraxial photography. Theory is developed showing how this sample can be measured by two-dimensional spatial correlation analysis, followed by deconvolution to remove the effects of finite particle image size. The probability density measurements are biased inherently against large velocities, but these effects can be minimized and/or corrected. 相似文献