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141.
Juliette Venel 《Numerische Mathematik》2011,118(2):367-400
The aim of this paper is to study a whole class of first order differential inclusions, which fit into the framework of perturbed
sweeping process by uniformly prox-regular sets. After obtaining well-posedness results, we propose a numerical scheme based
on a prediction-correction algorithm and we prove its convergence. Finally we apply these results to a problem coming from
the modelling of crowd motion. 相似文献
142.
We report on a large‐scale synthesis of F‐PNA trimer 10 and PNA trimer 11 . The key improvement is the facile two‐step synthesis of (2,4‐difluoro‐5‐methylphenyl)acetic acid ( 2 ). Water solubility of the corresponding F‐PNA oligomer 10 was achieved by synthesizing solubility enhancer 5a , which is twofold positively charged and only consists of inherent structural elements of PNA. Protected and unpaired PNA n‐mers exist in a mixture of 2n conformers undergoing slow exchange and leading to complicated NMR spectra. Structure analysis was improved by recording 1H‐ and 13C‐NMR spectra at elevated temperatures above the coalescence point. Fully protected backbone derivatives show sharp resonances where expected, and spectra of protected PNAs are remarkably simplified, thereby allowing an interpretation for the first time. Both trimers 10 and 11 are considered as building blocks for a self‐replicating system based on PNA. 相似文献
143.
Levels of nicotine higher than the maximum residue level were detected in edible mushrooms. Analyses of self-collected and purchased dried mushrooms were performed with a QuEChERS approach. A small amount (2.5 g) of dried sample matrix was mixed with 5 mL sodium hydroxide solution, 2.5 g of sodium sulfate/sodium chloride mixture (4:1) and 5 mL ethyl acetate. The organic phase was cleaned by using dispersive solid-phase extraction and analysed by GC–MS–MS. The linear range of the method was 0.01–10.00 mg kg?1 and the limit of detection 0.006 mg kg?1 on dry weight basis by using EURACHEM method. 相似文献
144.
Anne-Solenn Le Hô Martine Regert Olivier Marescot Chloé Duhamel Juliette Langlois Tetsuo Miyakoshi Christophe Genty Michel Sablier 《Analytica chimica acta》2012
This paper focuses on the identification of several chemical markers of vegetal species of Oriental lacquers with the aim at providing a methodology consistent with sampling restrictions necessarily applied in the field of cultural heritage. The method proposed is based on rapid and easy single step thermally assisted hydrolysis–methylation (THM) pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) analysis that can be carried out with a minimum amount of matter (typically 10 μg for a sample collected on a museum or an archaeological object). 相似文献
145.
146.
147.
Ackleh AS Ioup GE Ioup JW Ma B Newcomb JJ Pal N Sidorovskaia NA Tiemann C 《The Journal of the Acoustical Society of America》2012,131(3):2306-2314
Long-term monitoring of endangered species abundance based on acoustic recordings has not yet been pursued. This paper reports the first attempt to use multi-year passive acoustic data to study the impact of the Deepwater Horizon oil spill on the population of endangered sperm whales. Prior to the spill the Littoral Acoustic Demonstration Center (LADC) collected acoustic recordings near the spill site in 2007. These baseline data now provide a unique opportunity to better understand how the oil spill affected marine mammals in the Gulf of Mexico. In September 2010, LADC redeployed recording buoys at previously used locations 9, 25, and 50 miles away from the incident site. A statistical methodology that provides point and interval estimates of the abundance of the sperm whale population at the two nearest sites is presented. A comparison of the 2007 and the 2010 recordings shows a decrease in acoustic activity and abundance of sperm whales at the 9-mile site by a factor of 2, whereas acoustic activity and abundance at the 25-mile site has clearly increased. This indicates that some sperm whales may have relocated farther away from the spill. Follow-up experiments will be important for understanding long-term impact. 相似文献
148.
Bostedt C Eremina E Rupp D Adolph M Thomas H Hoener M de Castro AR Tiggesbäumker J Meiwes-Broer KH Laarmann T Wabnitz H Plönjes E Treusch R Schneider JR Möller T 《Physical review letters》2012,108(9):093401
Femtosecond x-ray laser flashes with power densities of up to 10(14) W/cm(2) at 13.7 nm wavelength were scattered by single xenon clusters in the gas phase. Similar to light scattering from atmospheric microparticles, the x-ray diffraction patterns carry information about the optical constants of the objects. However, the high flux of the x-ray laser induces severe transient changes of the electronic configuration, resulting in a tenfold increase of absorption in the developing nanoplasma. The modification in opaqueness can be correlated to strong atomic charging of the particle leading to excitation of Xe(4+). It is shown that single-shot single-particle scattering on femtosecond time scales yields insight into ultrafast processes in highly excited systems where conventional spectroscopy techniques are inherently blind. 相似文献
149.
R. C. Jasan R. R. Plá R. Invernizzi M. Dos Santos 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(1):101-105
PM10 and PM2.5 samples were taken using a Gent sampler to characterize the atmospheric aerosol of Buenos Aires metropolitan
area. A total of 114 samples were collected from October 2005 to October 2006 at one urban site, every third day, for 24 h.
Samples were analyzed by neutron activation, and black carbon and mass concentration were determined. In both fractions, elemental
and gravimetric mass concentrations were compared with historical data. Enrichment factors, backward trajectories and factor
analysis were calculated. The attribution of pollution sources is discussed. 相似文献
150.
Tashmukhambetov AM Ioup GE Ioup JW Sidorovskaia NA Newcomb JJ 《The Journal of the Acoustical Society of America》2008,123(6):4094-4108
In the summer of 2003, the Littoral Acoustic Demonstration Center conducted an acoustic characterization experiment for a 21-element marine seismic exploration airgun array of total volume of 0.0588 m(3) (3590 in.(3)). Two Environmental Acoustic Recording System buoys, one with a desensitized hydrophone, were deployed at a depth of 758 m in a water depth of 990 m, near Green's Canyon in the Gulf of Mexico. Shots over a grid were recorded and calibrated to produce absolute broadband (up to 25 kHz) pressure-time dependencies for a wide range of offsets and arrival angles in the water column. Experimental data are analyzed to obtain maximum received zero-to-peak pressure levels, maximum received sound exposure levels, and pressure levels in 13-octave frequency bands for each shot. Experimental data are quantitatively modeled by using an upgraded version of an underwater acoustic propagation model and seismic source modeling packages for a variety of ranges and arrival angles. Experimental and modeled data show good agreement in absolute pressure amplitudes and frequency interference patterns for frequencies up to 1000 Hz. The analysis is important for investigating the potential impact on marine mammals and fish and predicting the exposure levels for newly planned seismic surveys in other geographic areas. 相似文献