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71.
Nicolas Le Calvez 《中国化学会会志》2002,49(4):585-592
The aim of this study was to develop an analytical method to determine the organochlorine concentrations in sediments. Combination of Microwave assisted Solvent Extraction (MASE) and capillary gas chromatography with specific detection (electron capture detector) was a viable approach for the determination of pesticides in solid matrixes. In this study, MASE development was focused on the selection of a suitable extraction solvent for all the target analytes. MASE procedure was validated by comparison with conventional methods such as Soxhlet and sonication extraction. The proposed method was then applied to determine the organochlorine insecticides concentrations in samples from Authie Bay (France). Environmental water samples were analysed and five target analytes were detected in concentrations from 0.03 to 0.56 ng/g of dry sediment. These investigations showed the accumulation and the persistency of these products in sediments in spite of the fact they were banned a few decades ago. 相似文献
72.
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Summary The existence of a joint asymptotic distribution for the windings of a three-dimensional Brownian motion around a finite number of straight lines is obtained. This complements the recent studies, by Pitman- Yor, and the authors, of the joint asymptotic distribution for the windings of planar Brownian motion around a finite number of points.The following principle governs the passage from results in the plane to results in space:Let B be a three-dimensional Brownian motion, and P
1, ..., P
k, k planes which intersect two by two. Then, the convergences in distribution concerning the planar Brownian motions B
i (1ik), defined respectively as the orthogonal projections of B on P
i (1ik), take place jointly, and the corresponding limit variables are independent. 相似文献
75.
76.
J. Kuriplach L. Lešták M. Rotter B. Sedlák M. Trhlík M. Finger T. Lešner J. Dupák P. Novák M. Vobecký 《Hyperfine Interactions》1987,34(1-4):339-342
First experimental results of160Tb nuclear orientation in yttrium single crystal matrix are described. The influence of external magnetic field in combination with the crystal field interaction is discussed. 相似文献
77.
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The synthesis of a biotinated amphiphile assembled from d-(+)-biotin, ethylene diamine as spacer, galactaric acid and 1-dodecylamine was achieved in six steps. The key step was the synthesis of a bisacetonide protected galactaric ester, the structure of which was determined by X-ray analysis. Aminolysis, spacer attachment, coupling with biotin and deprotection led to the amphiphilic galactaramide. 相似文献
79.
Sabine Schmid 《Journal of solid state chemistry》2003,174(1):221-228
The novel alkaline earth silicate borate cyanides Ba7[SiO4][BO3]3CN and Sr7[SiO4][BO3]3CN have been obtained by the reaction of the respective alkaline earth metals M=Sr, Ba, the carbonates MIICO3, BN, and SiO2 using a radiofrequency furnace at a maximum reaction temperature of 1350°C and 1450°C, respectively. The crystal structures of the isotypic compounds MII7[SiO4][BO3]3CN have been determined by single-crystal X-ray crystallography (P63mc (no. 186), Z=2, a=1129.9(1) pm, c=733.4(2) pm, R1=0.0336, wR2=0.0743 for MII=Ba and a=1081.3(1) pm, c=695.2(1) pm, R1=0.0457, wR2=0.0838 for MII=Sr). Both ionic compounds represent a new structure type, and they are the first examples of silicate borate cyanides. The cyanide ions are disordered and they are surrounded by Ba2+/Sr2+ octahedra, respectively. These octahedra share common faces building chains along [001]. The [BO3]3− ions are arranged around these chains. The [SiO4]4− units are surrounded by Ba2+/Sr2+ tetrahedra, respectively. The title compounds additionally have been investigated by 11B, 13C, 29Si, and 1H MAS-NMR as well as IR and Raman spectroscopy confirming the presence of [SiO4]4−, [BO3]3−, and CN− ions. 相似文献
80.
Carlier J Arscott S Thomy V Camart JC Cren-Olivé C Le Gac S 《Journal of chromatography. A》2005,1071(1-2):213-222
We report here on an integrated microfabricated device dedicated to the preparation of biological samples prior to their on-line analysis by electrospray ionization-mass spectrometry (ESI-MS). This microfluidic device is fabricated using the negative photoresist SU-8 by microtechnology techniques. The device includes a chromatographic module plus an ESI interface for MS. The chromatographic module is dedicated to sample purification and is based on a polymer monolithic phase which includes hydrophobic moieties. The ESI interface is integrated onto the chip and is based on a capillary slot. We present here the integration of these different modules onto a single system that is fabricated via a SU-8-based microtechnology route. We present also their testing for the purification of peptide samples. This started with a partial integration step with the combination of at least two of the modules (microsystem + monolith; microsystem + nib) and their test before the fabrication and testing of fully integrated microsystems. 相似文献