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91.
Battesti R Fouché M Detlefs C Roth T Berceau P Duc F Frings P Rikken GL Rizzo C 《Physical review letters》2010,105(25):250405
In this Letter we describe our novel photon regeneration experiment for the axionlike particle search using an x-ray beam with a photon energy of 50.2 and 90.7 keV, two superconducting magnets of 3 T, and a Ge detector with a high quantum efficiency. A counting rate of regenerated photons compatible with zero has been measured. The corresponding limits on the pseudoscalar axionlike particle-two-photon coupling constant is obtained as a function of the particle mass. Our setup widens the energy window of purely terrestrial experiments devoted to the axionlike particle search by coupling to two photons. It also opens a new domain of experimental investigation of photon propagation in magnetic fields. 相似文献
92.
Aurora Modica Marco Di Bella Maria Francesca Alberghina Maria Brai Dorotea Fontana 《Natural product research》2019,33(7):987-996
AbstractThe subject of this present work is a group of nine historical pictures shot in Palermo by the Sicilian photographer E. Interguglielmi in 1912. They are nine matte-collodion prints mounted on the original cardboard supports and all of them show foxing stains affecting the paper surface. In order to characterise the chemical composition of the supports and investigate foxing spots, non-destructive and micro-destructive analysis were carried out. X-rays fluorescence (XRF) analysis was used to characterise the elemental composition of all the mounting boards, allowing a comparison between the foxing spots and non-affected areas. Laser-Induced Breakdown Spectroscopy was used to investigate the presence of lower atomic number elements, not detectable by XRF, while SEM imaging allowed the investigation of surface appearance and nature of original paper samples from the cardboards. 相似文献
93.
Birarda Giovanni Delneri Ambra Lagatolla Cristina Parisse Pietro Cescutti Paola Vaccari Lisa Rizzo Roberto 《Analytical and bioanalytical chemistry》2019,411(27):7315-7325
Analytical and Bioanalytical Chemistry - Biofilms are communities of bacteria living embedded in a highly hydrated matrix composed of polysaccharides, proteins, and extracellular DNA. This life... 相似文献
94.
Giuseppe E. De Benedetto Silvia Nicolì Antonio Pennetta Daniela Rizzo Luigia Sabbatini Annarosa Mangone 《Journal of Raman spectroscopy : JRS》2011,42(6):1317-1323
Painted Canosa ceramics were examined to identify the nature of the pigments employed and their manufacturing technology. A multi‐technique approach was used, comprising Raman microspectroscopy and laser ablation hyphenated to inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS). The analysed samples were mainly produced for burial in tombs and were not intended for everyday use. They belong to the period between the end of the mid‐7th century and the first half of the 4th century BC, and were excavated from the Toppicelli archaeological district near the suburbs of Canosa (Puglia, Italy). Forty‐eight pottery fragments were available for this study. No handling of the samples was required for the Raman study, and it was possible to excise the pigmented layer in such a way that the lacunae were not distinguishable to the naked eye due to the micrometric size of the laser spot as far as LA‐ICP‐MS is concerned. Their combination turned out to be quite useful for the investigation of these archaeological materials: the chemical nature of the white, red, brown and black pigments employed in the pottery manufacture was investigated. Iron and manganese compounds were identified as the red and brown/black main colouring substances, respectively; on the other hand, whites and engobes (whitish slips) were based on kaolinite. This set of colouring substances is of importance, as it enabled the artisan to obtain in one oxidising firing cycle brown, black and red paints. Finally, the finding of manganese black in these Canosa potsherds confirms that Canosa was an important centre connecting the near East to central Italy and Europe since the pre‐Roman age. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
95.
Ana Maria Percebom Vinícius Jesus Towesend Marina de Paula Silva de Andrade Pereira Aurora Pérez Gramatges 《Current Opinion in Green and Sustainable Chemistry》2018
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96.
Rizzo A 《Analytical and bioanalytical chemistry》2008,392(1-2):47-55
As a non-invasive or micro-invasive technique attenuated total reflectance Fourier transform infrared spectroscopic (ATR-FTIR) microscopy is a valuable tool for the analysis of materials in works of art. An application for which it has received growing interest is in the analysis of paint cross-sections. However, FTIR microscope configurations, objectives' geometries and low spatial resolutions, and issues of sample preparation have often hampered the characterization of individual layers or features in cross-sections. With the use of case studies, it is demonstrated here that an ATR-FTIR microscope featuring a crystal of optimized geometry and a viewing capability feature allows characterization of individual layers, or areas within layers, of 10 microm thickness or less in single measurements. Of particular value is a remote aperturing feature which allows the analysis of selected areas within the contact footprint of the ATR crystal. Since the technique is non-destructive, the same area can be analyzed by complementary microscopic techniques such as Raman spectroscopy and scanning electron microscopy with energy-dispersive spectroscopy. Pyrolysis gas chromatography-mass spectrometry was also used in some cases to corroborate the spectroscopic data. The analyses presented provided data which were important in informing art historical interpretation and conservation of the artworks examined. 相似文献
97.
The asymmetric alkoxycarbonylation of vinylarenes catalysed by palladium complexes bearing chiral phosphine ligands has attracted much attention over the last decades. The products of both mono- and bis(alkoxycarbonylation) reactions are important intermediates in the syntheses of pharmaceuticals such as 2-arylpropionic acids, the most important class of non-steroidal anti-inflammatory drugs. In this article, a general overview of the topics will be presented and the recent advances in this field will be particularly detailed. Besides the term alkoxycarbonylation, hydroesterification and hydroalkoxycarbonylation are also used in the literature to describe this reaction. Furthermore, more specific terms such as methoxycarbonylation can be found. In this report, the term alkoxycarbonylation will be used as the general term, and specific terms will be used to unambiguously define which reaction is meant. 相似文献
98.
Giovanni Neri Giuseppe Rizzo Lidia De Luca Andrea Donato Maria Grazia Musolino Rosario Pietropaolo 《Reaction Kinetics and Catalysis Letters》2008,93(2):193-202
Selective catalytic reduction of campholenic aldehyde to naturanol was investigated over Sn-and Fe-doped SiO2, and Fe2O3-supported Pd catalysts. On Pd/SiO2 and Pd-Sn/SiO2 only saturated campholenic aldehyde is formed. Addition of Fe increases the C=O hydrogenation rate producing the corresponding
unsaturated alcohol with a good selectivity. Also Fe2O3-supported catalysts were found to be more selective towards carbonyl hydrogenation. Addition of tin to Pd/Fe2O3 contributes to a further selectivity enhancement towards naturanol. 相似文献
99.
Lin N Santoro F Zhao X Rizzo A Barone V 《The journal of physical chemistry. A》2008,112(48):12401-12411
The vibrationally resolved electronic circular dichroism (ECD) spectra of the two dominant conformers of (R)-(+)-3-methylcyclopentanone in gas phase are computed by density functional response theory, with a full account of Franck-Condon and Herzberg-Teller vibrational contributions at the harmonic level. Proper inclusion of the latter contributions was made possible by the recent implementation of effective-scaling computations of vibrational overlaps and of analytical gradients of time dependent DFT. The Coulomb-attenuated Becke three parameters Lee-Yang-Parr (CAM-B3LYP) functional reproduces both the position and the intensity of the experimental peaks, providing a remarkable improvement over the spectra obtained with the popular hybrid B3LYP functional, and allowing a confident assignment of the CD fine vibrational structure. Franck-Condon and Herzberg-Teller contributions are discussed in detail. The computed decrease of the CD intensity in the gas phase upon increase of the temperature of the sample follows the trend observed experimentally in different solvents. 相似文献
100.
Cruz-Cabeza AJ Day GM Jones W 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(29):8830-8836
We report on the crystal structure of urea (U) with acetic acid (A), its physical stability and its predictability using computational methods. The crystal structure of urea:acetic acid (U:A) shows hydrogen-bond ribbons and a 1:2 stoichiometry. Crystal structure prediction calculations are presented for two sets of U:A stoichiometries: 1:1 and 1:2. A 1:3 stoichiometry is also partially explored by means of a synthon approach. The calculated lattice energies, along with hydrogen-bond patterns, of crystal structures predicted with the three stoichiometries are presented and analysed to provide a rationalisation for the stoichiometry observed. Exploring stoichiometric diversity using computational methods provides a tool for the rationalisation of stoichiometry preferences in crystalline multicomponent systems and a first step towards their prediction. 相似文献