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Varietal discrimination of Australian wines by means of mid-infrared spectroscopy and multivariate analysis 总被引:1,自引:0,他引:1
This study outlines the use of mid-infrared (MIR) spectroscopy combined with principal component analysis (PCA) and linear discriminant analysis (LDA) for the varietal classification of commercial red and white table wines. Three red varieties (Cabernet Sauvignon, Shiraz and Merlot) and four white varieties (Chardonnay, Riesling, Sauvignon Blanc and Viognier) were sourced from different wine regions in Australia. Wine samples were scanned in transmission on a FOSS WineScan FT 120 from wave numbers 926 to 5012 cm−1. All samples were sourced from the 2006 vintage and had not been blended with any other variety or wine from other regions. Spectral data were reduced to a small number of principal components (PCs) and LDA was then performed to successfully separate the wines into the different varieties. To test the robustness of the LDA models developed for the red wines, a set of red wines scanned in 2005 were used. Correct classification of over 95% was achieved for the validation set. 相似文献
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The technique of ferromagnetic resonance at 23 GHz has been used to determine the first three anisotropy constants of pure Ni down to 4.2K. A temperature and orientation dependent linewidth has also been observed. 相似文献
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Sinkov SI Rapko BM Lumetta GJ Hay BP Hutchison JE Parks BW 《Inorganic chemistry》2004,43(26):8404-8413
This report describes affinity measurements for two, water-soluble, methyl-alkylated diamides incorporating the malonamide functionality, N,N,N',N' tetramethylmalonamide (TMMA) and a bicyclic diamide (1a), toward actinide metal cations (An) in acidic nitrate solutions. Ligand complexation to actinides possessing oxidation states ranging from +3 to +6 was monitored through optical absorbance spectroscopy, and formation constants were obtained from the refinement of the spectrophotometric titration data sets. Species analysis gives evidence for the formation of 1, 4, 1, and 2 spectrophotometrically observable complexes by TMMA to An(III, IV, V, and VI), respectively, while for 1a, the respective numbers are 3, 4, 2, and 2. Consistent with the preorganization of 1a toward actinide binding, a significant difference is found in the magnitudes of their respective formation constants at each complexation step. It has been found that the binding affinity for TMMA follows the well-established order An(V) < An(III) < An(VI) < An(IV). However, with 1a, Np(V) forms stronger complexes than Am(III). The complexation of 1a with Np(V) and Pu(VI) at an acidity of 1.0 M is followed by reduction to Np(IV) and Pu(IV), whereas TMMA does not perturb the initial oxidation state for these dioxocations. These measurements of diamide binding affinity mark the first time single-component optical absorbance spectra have been reported for a span of actinide-diamide complexes covering all common oxidation states in aqueous solution. 相似文献
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James R. Vyvyan Jennifer M. Oaksmith Bevin W. Parks Elaine M. Peterson 《Tetrahedron letters》2005,46(14):2457-2460
The total synthesis of heliannuol C and E from a common intermediate are described. Key steps in the synthesis include a regioselective aromatic Claisen rearrangement to install the (1-vinyl)-4-methyl-3-pentenyl substituent and regioselective biomimetic 7-endo and 6-exo phenol epoxide cyclizations to form the cyclic ether moieties. 相似文献
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Michael addition of N-lithio-4-vinyl-azetidin-2-one to several vinyl phosphonates gave adducts which were converted to Δ-1 carbopenems via ozonolysis and an intramolecular Horner-Wittig reaction. 相似文献