排序方式: 共有9条查询结果,搜索用时 234 毫秒
1
1.
Dommergue A Bahlmann E Ebinghaus R Ferrari C Boutron C 《Analytical and bioanalytical chemistry》2007,388(2):319-327
Snow surfaces play an important role in the biogeochemical cycle of mercury in high-latitude regions. Snowpacks act both as
sources and sinks for gaseous compounds. Surprisingly, the roles of each environmental parameter that can govern the air–surface
exchange over snow are not well understood owing to the lack of systematic studies. A laboratory system called the laboratory
flux measurement system was used to study the emission of gaseous elemental mercury from a natural snowpack under controlled
conditions. The first results from three snowpacks originating from alpine, urban and polar areas are presented. Consistent
with observations in the field, we were able to reproduce gaseous mercury emissions and showed that they are mainly driven
by solar radiation and especially UV-B radiation. From these laboratory experiments, we derived kinetic constants which show
that divalent mercury can have a short natural lifetime of about 4–6 h in snow. 相似文献
2.
3.
Lohmeyer M. Bahlmann N. Zhuromskyy O. Hertel P. 《Optical and Quantum Electronics》1999,31(9-10):877-891
Coupled mode theory is applied to an arrangement of three raised strip waveguides with a multimode central strip. We use semivectorial numerically computed modes of the three single isolated waveguides as a basis for propagating supermode analysis of the entire structure. The pronounced polarization dependence of the raised strip guides allows for the design of a conveniently short polarization splitter. We discuss design guidelines and estimate the fabrication tolerances. The accuracy of the coupled mode approach is assessed by comparison with rigorously computed supermodes for comparable two waveguide couplers. Both types of structures indicate the limits in the applicability of the coupled mode model. 相似文献
4.
K. Fischer C. H. Weiss P. Woog E. Masters A. E. Goddard S. W. Ferris F. Höppler O. Scarpa L. Steiner St. M. Rogers L. R. Adkins H. Mallison H. Vollmann A. Ter-Pogossjan E. Schlenker J. Givaudon A. C. Galletti F. L. de Beaukelaer J. R. Powell E. F. Bahlmann 《Analytical and bioanalytical chemistry》1933,95(9-10):342-348
5.
Monitoring carbamazepine in surface and wastewaters by an immunoassay based on a monoclonal antibody
Arnold Bahlmann Michael G. Weller Ulrich Panne Rudolf J. Schneider 《Analytical and bioanalytical chemistry》2009,395(6):1809-1820
The pharmaceutical compound carbamazepine (CBZ) is an emerging pollutant in the aquatic environment and may potentially be
used as a wastewater marker. In this work, an enzyme-linked immunosorbent assay (ELISA) for the detection of carbamazepine
in surface and sewage waters has been developed. The heterogeneous immunoassay is based on a commercially available monoclonal
antibody and a novel enzyme conjugate (tracer) that links the hapten via a hydrophilic peptide (triglycine) spacer to horseradish
peroxidase. The assay achieves a limit of detection of 24 ng/L and a quantitation range of 0.05–50 μg/L. The analytical performance
and figure of merits were compared to liquid chromatography–tandem mass spectrometry after solid-phase extraction. For nine
Berlin surface water samples and one wastewater sample, a close correlation of results was observed. A constant overestimation
relative to the CBZ concentration of approximately 30% by ELISA is probably caused by the presence of 10,11-epoxy-CBZ and
2-hydroxy-CBZ in the samples. The ELISA displayed cross-reactivities for these compounds of 83% and 14%, respectively. In
a first screening of 27 surface water samples, CBZ was detected in every sample with concentrations between 0.05 and 3.2 μg/L.
Since no sample cleanup is required, the assay allowed for the determination of carbamazepine with high sensitivity at low
costs and with much higher throughput than with conventional methods.
相似文献
6.
Zhuromskyy O. Lohmeyer M. Bahlmann N. Hertel P. Dötsch H. Popkov A.F. 《Optical and Quantum Electronics》2000,32(6-8):885-897
We investigate a structure consisting of a magneto-optic multimode waveguide and two monomode waveguides serving as in- and outlets. The geometrical dimensions of the multimode waveguide can be adjusted such that the guided modes interfere constructively in forward direction and destructively for backward propagation. In this paper we present concepts for a circulator and two isolators based on multimode imaging. 相似文献
7.
Bahlmann N. Lohmeyer M. Wallenhorst M. Dötsch H. Hertel P. 《Optical and Quantum Electronics》1998,30(5-6):323-334
Non-reciprocal rib waveguide structures can be used to realize integrated optical isolators. In this paper, we propose a concrete design for a Mach–Zehnder interferometer type isolator for TM modes. Just one of the arms, which are of equal length, is a non-reciprocal magneto-optic waveguide. The rest of the interferometer is reciprocal. Required fabrication tolerances are estimated, and the entire isolator is simulated by applying a finite difference beam propagation method. 相似文献
8.
High performance liquid chromatography (HPLC) was hyphenated with a previously reported carbamazepine-specific enzyme-linked immunosorbent assay (ELISA) as a screening approach to water analysis in order to identify possible interferences from transformation products. Treated wastewater was analysed and three substances were recognized by the antibody besides carbamazepine: the metabolites 10,11-dihydro-10,11-epoxycarbamazepine and 2-hydroxycarbamazepine plus the structurally not obviously related antihistamine cetirizine. The molar cross-reactivity against cetirizine was found to be pH-dependent and assessed to be 400% at pH 4.5 and 22% at pH 10.5. Performing the ELISA at pH 10.5 greatly improved the accuracy when carbamazepine was determined in surface and wastewater samples. 相似文献
9.
Summary This paper provides a fast and storage-saving method for the solution of the first biharmonic boundary value problem (b.v.p.). The b.v.p. is approximated via a special variational finite difference technique suggested earlier by V.G. Korneev. It is shown theoretically that our method produces an approximate solution to the finite difference equations inO(NlnNln–1) arithmetical operations, whereN is the number of unknowns and (0<<1) denotes the relative accuracy required. The numerical results obtained by our computer code CGMFC decisively substantiate the theoretical estimates given. 相似文献
1