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821.
Mohamed Osman Awaleh Antonella Badia François Brisse 《Journal of chemical crystallography》2009,39(2):122-127
Abstract Two new silver(I)–dithioether coordination polymers based on the self-assembly of the dithioether ligands L
n
−R
= CH3–S(CH2)
n
S–CH3 (n = 1, 3) and AgX silver salts, where X = ClO4
− (1) and PF6
− (2), have been synthesized and characterized by single crystal X-ray diffraction and TGA. The crystallographic data of those
complexes are: (1) Monoclinic P21/c; a = 16.5861(3) ?; b = 10.1048(2) ?; c = 15.7843(3) ?; β = 112.570(1)°; V = 2442.83(8) ?3; Z = 4. (2) Monoclinic P21/n; a = 8.6500(2) ?; b = 9.4053(2) ?; c = 24.0357(6) ?; β = 92.750(2)°; V = 1953.19(8) ?3; Z = 4. In both complexes, the dithioether building blocks propagated the silver(I) centers to build cationic lamellar coordination
polymers, while ClO4
− and PF6
−, which were sandwiched between silver-ligand sheets, counterbalance only the charge of the networks. The thermogravimetric
investigation reveals that those complexes decompose in a single step respectively to metallic silver and silver salt.
Index Abstract Two new silver(I)–dithioether coordination polymers, obtained from the self-assembly of dithioether ligands and AgX salts
with noncoordinating counteranions (X = ClO4
− and PF6
−), were characterized by X-ray crystallography and thermogravimetric analysis (TGA). 相似文献
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826.
Mauro F. La Russa Silvestro A. Ruffolo Cristina M. Belfiore Valeria Comite Antonella Casoli Michela Berzioli Gianluca Nava 《Applied Physics A: Materials Science & Processing》2014,114(3):733-740
During the last restoration of the six paintings by Raffaele Rinaldi (1851–1916), located in the church of Maria SS. Annunziata (Marano Principato, Cosenza, Italy), made between 1890 and 1903, several scientific investigations were carried out on them. The present work aims at classifying the painting in terms of its materials and technical particularities. The goal of this study was to characterise the painting technique of the painter, its evolution and possible additions made during previous restorations. Pigments, binder media and raw materials used for the application of the ground and the paint layers were studied using electronic microscopy equipped with energy dispersive spectroscopy qualitative microanalysis (SEM-EDS), infrared spectroscopy (FTIR) and gas chromatography coupled with mass spectrometry (GC/MS). Furthermore, a complete analysis of the state of preservation of these paintings represents a scientific aid and guide for its restoration, taking into account the severe damage not exclusively due to natural decay processes. Our data can provide information about historical and stylistic background as well as advise for correct planning of the cleaning procedures. The identification of materials allowed a correct restoration. 相似文献
827.
Olive oil has great human health benefits and is an important component of the Mediterranean diet. Its quality, sensory attributes, and oxidative stability are linked to the presence of minor compounds. Vitamin E (α-tocopherol) is a key component in these properties. In this work, solid-phase microextraction coupled to gas chromatography–mass spectrometry was used for the determination of α-tocopherol in olive oil. The analytical performance of the method has been assessed in fortified olive oil with negligible vitamin E concentrations. The calibration curve was linear from 0.020 to 0.500?mg/g. The limits of detection and quantification were 0.006 and 0.021?mg/g, respectively. Intraday and interday relative standard deviations were 3.2 and 10.0, respectively, and were concentration independent. The method was used for the determination of α-tocopherol in virgin and extra virgin olive oil, reporting average concentrations of 0.044?±?0.03 and 0.200?±?0.05?mg/g, respectively. Overall, the method is simple, sensitive, rapid, and solvent free, and provided high recoveries of 97.7?±?3.1%. In addition, vitamin E stability in extra-virgin olive oil was characterized by a shelf-life study. 相似文献
828.
829.
F. Grassi 《Zeitschrift fur Physik C Particles and Fields》1988,38(1):307-316
An equation of state is computed for a plasma of one flavour quarks interacting through some phenomenological potential, at zero temperature. Assuming that the confining potential is scalar and colour-independent, it is shown that the quarks undergo a first-order mass phase transition. In addition, due to the way screening is introduced, all the thermodynamic quantities computed are independent of the actual shape of the interquark potential. This equation of state is then generalized to a several quark flavour plasma and applied to the study of the hadron-quark phase transition inside a neutron star. 相似文献
830.
Roberta Bernini Antonietta CorattiGiancarlo Fabrizi Antonella Goggiamani 《Tetrahedron letters》2003,44(50):8991-8994
The Baeyer-Villiger oxidation of cyclic ketones can be effected by methyltrioxorhenium/hydrogen peroxide in the ionic liquid [bmim]BF4. After simple extraction of the lactone with diethyl ether, the catalyst can be repeatedly recycled and efficiently reused for the lactonisation process in the same reaction medium. 相似文献