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11.
Demetrio Pitea Laura Bonati Elena Collina Ugo Cosentino Marina Lasagni Giorgio Moro Roberto Todeschini 《Fresenius' Journal of Analytical Chemistry》1994,348(1-2):111-120
Summary The role of multivariate analysis methods in evaluating, rationalizing, and working out complex environmental problems is discussed. The discussion is organized in two sections; a literature analysis of the application of chemometric methods to PCDD/PCDF data interpretation and source correlation and a review of the role of chemometric methods in analysing the results obtained by the Authors studying PCDD/PCDF formation and destruction mechanisms in MSW combustion processes. 相似文献
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The authors give error estimates, a Voronovskaya-type relation, strong converse results and saturation for the weighted approximation of functions on the real line with Freud weights by Bernstein-type operators. 相似文献
14.
The Fourier transform of orthogonal polynomials with respect to their own orthogonality measure defines the family of Fourier–Bessel
functions. We study the asymptotic behaviour of these functions and of their products, for large real values of the argument.
By employing a Mellin analysis we construct a general framework to exhibit the relation of the asymptotic decay laws to certain
dimensions of the orthogonality measure, that are defined via the divergence abscissas of suitable integrals. The unifying
r?le of Mellin transform techniques in deriving classical and new results is underlined.
Submitted: November 5, 2004. Accepted: January 6, 2006. 相似文献
15.
This paper presents the preliminary results obtained using an Electron Paramagnetic Resonance imaging apparatus operating at 280 MHz. The acquisition technique and the procedure used to obtain the spin density spatial localization are presented and specimen images of extended samples are given. The accuracy of the images and the spatial resolution are also discussed. 相似文献
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Beverina L Abbotto A Landenna M Cerminara M Tubino R Meinardi F Bradamante S Pagani GA 《Organic letters》2005,7(19):4257-4260
[graph: see text] Condensation of squaric acid with a number of differently substituted 2-pyrrolyl derivatives afforded three new classes of squaraines. Their sharp and intense absorption bands in the biological window (700-900 nm), inherent singlet oxygen generation capabilities, together with proper functionalization allowing good water solubility make them suitable candidates as new non-porphyrinic singlet oxygen photosensitizers for photodynamic therapy (PDT). 相似文献
19.
Alberto Sturaro Giorgio Parvoli Lucio Doretti Cristina Bancomina Carlo Neonato 《Journal of mass spectrometry : JMS》1994,29(10):575-577
The determination of vinyl acetate at parts per 109 by volume (ppbv) levels in air by gas chromatography/mass spectrometry (GC/MS) was achieved by optimizing the GC conditions and choosing specific extraction solvents that are sufficiently pure. The ideal solvent should not give rise to fragment ions at m/z 43, in order to rule out any possible interference during the monitoring of the same vinyl acetate ion. Traces of acetone and butan-2-one in solvents suitable for this GC/MS determination may also mislead the detection of vinyl acetate. A 440 μl volume of a mixture of tetrachloroethylene containing 9% acetonitrile allowed the recovery of more than 90% of the ester with a detection limit of 1.5 ppbv in air together with a good linearity of response. 相似文献
20.
Silver clusters grown by the inert gas aggregation technique have been investigated by HREM. Undistorted cuboctahedra and icosahedra together with twinned particles have been observed. Three types of nucleation and growth mechanisms are proposed which can explain the observed particle structures. The untwinned large particles are created by the coalescence of liquid- like small clusters. The twins are produced by the coalescence of solid subunits. 相似文献