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The subject of this work is an investigation of the effects of surface anisotropy in ferromagnetic resonance (FMR) in bulk metal samples. The surface anisotropy (with arbitrary values of the constantK
s) is included in the equations of the macroscopic theory of FMR in the so called parallel experimental configuration. Its influence on the inflexion linewidth and on the resonance field correction is illustrated graphically for a typical value of the exchange-conductivity parameterE. It is also shown that experimental determination of the resonance parameters for samples with different surface orientations enables one to decide whether the Néel anisotropy dominates in the surface conditions. 相似文献
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Dr. Martin Kamlar Dr. Ivana Císařová Prof. Jan Veselý 《European journal of organic chemistry》2023,26(32):e202300400
We report a Brønsted acid-catalyzed synthesis of tetrasubstituted allenyl compounds decorated with heterocyclic sulfenyl group. The reaction proceeds readily from available propargylic alcohols in the presence of pentacarboxycyclopenatadienes (PCCPs) as organocatalysts. The developed strategy provides tetrasubstituted allene derivatives in high yields (from 55 to 98 %) and under mild reaction conditions. 相似文献
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Emanuele Casini Enrico Miglierina Łukasz Piasecki Libor Veselý 《Israel Journal of Mathematics》2016,216(1):355-369
We present a Lindenstrauss space with an extreme point that does not contain a subspace linearly isometric to c. This example disproves a result stated by Zippin in a paper published in 1969 and it shows that some classical characterizations of polyhedral Lindenstrauss spaces, based on Zippin’s result, are false, whereas some others remain unproven; then we provide a correct proof for those characterizations. Finally, we also disprove a characterization of polyhedral Lindenstrauss spaces given by Lazar, in terms of the compact norm-preserving extension of compact operators, and we give an equivalent condition for a Banach space X to satisfy this property. 相似文献
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Veselá A Barros AS Synytsya A Delgadillo I Copíková J Coimbra MA 《Analytica chimica acta》2007,601(1):77-86
The combination of the near infrared (NIR) and Fourier-transform infrared (FTIR) absorbance spectra (1100-2500 nm and 4000-600 cm−1) of 100 cocoa powder samples was used to build calibration models for the determination of the content of fat, nitrogen, and moisture. The samples that comprised the dataset had an average composition of 13.51% of fat, 3.77% nitrogen, and 3.98% moisture. The fat content ranged from 2.42 to 22.00%, the nitrogen from 0.88 to 4.48%, and moisture from 1.60 to 7.80%. For NIR, the relative root mean square error of cross-validation (RMSECV) was 7.0% (R2 = 0.96) for fat, 1.7% (R2 = 0.98) for nitrogen, and 5.2% (R2 = 0.94) for moisture. For FTIR, the relative RMSECV was 10.4% (R2 = 0.94) for fat and 3.9% (R2 = 0.95) for nitrogen. However, for moisture, it was not possible to build a calibration model with suitable predictability. The combination of the NIR and FTIR domains (data fusion) by outer product analysis PLS1 allowed to predict these parameters and to characterise frequencies in one domain based on the information of the other domain. This work allows to conclude that the second derivative of NIR is the recommended procedure to quantify fat, nitrogen, and moisture content in cocoa powders by infrared spectroscopy. 相似文献
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An analytical method for the determination of amitraz residues in beeswax after hydrolysis to 2,4-dimethylaniline is reported. It consists of wax extraction with an acid buffer solution, head space solid phase microextraction and GC-ITD analysis. The limit of determination is 1 ng g−1. Wax samples from beekepers and commercial foundations were analysed, content of residues varied from <1 to 20.5 ng g−1. 相似文献