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121.
122.
Silvia Vicini Alberto Mariani Elisabetta Princi Simone Bidali Silvia Pincin Stefano Fiori Enrico Pedemonte Antonio Brunetti 《先进技术聚合物》2005,16(4):293-298
Polymeric products are largely used for consolidation of stone in the field of cultural heritage. Nevertheless, the main problem of polymeric compounds is related to their macromolecular nature, it being difficult for a polymer to penetrate inside the pores which may have a very small diameter. These considerations are the starting points for in situ polymerization. According to this technique, not the pre‐formed polymer, but the monomer is introduced into the stone and it is polymerized in situ in a subsequent step. Frontal polymerization (FP) is a particular technique in which the heat released by the exothermal reaction of monomer to polymer conversion is exploited to promote the formation of a hot traveling front able to propagate and self‐sustain the reaction. In the present work, FP is performed inside the pores of the stone and the results lead to the conclusion that the hot front is still active in the presence of an inorganic material which dissipates partially the heat released during the polymerization. In addition some recent applications of FP are discussed in comparison with the traditional polymerization for the in situ consolidation and protection of stones. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
123.
Brunetti FG Varotto A Batara NA Wudl F 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(31):8604-8608
We have designed the synthesis of "deconvoluted fullerene" derivatives that present an ordered pattern of hexagons and pentagons in the backbone of the molecule. We not only mimicked the fullerene structure in dihedral planes, but also preserved its electron accepting behavior and enlarged its optical absorption. Moreover, very preliminary photoluminescence (PL) quenching experiments also confirmed the potentiality of these materials as acceptors in the field of organic photovoltaics (OPV)s. A brief discussion of the surface morphology, based on AFM analysis, is also presented. 相似文献
124.
The uncertainty of measurement is the key indicator of the quality of any experimental result. Proper consideration of this
uncertainty is imperative when testing a sample against legal/compositional limits. This task can be quite challenging when
the entity measured in the investigated sample is so close to the limit that its uncertainty, however estimated, critically
affects decision-making. This explains the many literature contributions discussing the problem. Even though some of the most
authoritative organisations have issued specific guidelines aimed at assisting the staff involved in such measurements, several
aspects of conformity testing are still debated in the literature. In this review, after a short outline of existing information,
somewhat more detailed insight is given into the guidelines of ASME, ISO, and Eurachem/CITAC, because they are the most useful
tools for operators of testing and calibration laboratories. Some aspects of Council Directive 96/23/EC are also discussed.
Insight into the contents of the mentioned documents enables emphasis of analogies and discrepancies. 相似文献
125.
Dovigo LN Pavarina AC Ribeiro AP Brunetti IL Costa CA Jacomassi DP Bagnato VS Kurachi C 《Photochemistry and photobiology》2011,87(4):895-903
This study describes the association of curcumin with light emitting diode (LED) for the inactivation of Candida albicans. Suspensions of Candida were treated with nine curcumin concentrations and exposed to LED at different fluences. The protocol that showed the best outcomes for Candida inactivation was selected to evaluate the effect of the preirradiation time (PIT) on photodynamic therapy (PDT) effectiveness, the uptake of curcumin by C. albicans cells and the possible involvement of singlet oxygen in the photodynamic action. Curcumin-mediated PDT was also assessed against biofilms. In addition to the microbiological experiments, similar protocols were tested on a macrophage cell line and the effect was evaluated by Methyltetrazolium assay (MTT) and SEM analysis. The optical properties of curcumin were investigated as a function of illumination fluence. When compared with the control group, a statistically significant reduction in C. albicans viability was observed after PDT (P < 0.05), for both planktonic and biofilm cultures. Photodynamic effect was greatly increased with the presence of curcumin in the surrounding media and the PIT of 20 min improved PDT effectiveness against biofilms. Although PDT was phototoxic to macrophages, the therapy was more effective in inactivating the yeast cell than the defense cell. The spectral changes showed a high photobleaching rate of curcumin. 相似文献
126.
127.
Tert-butyl chloride has been broadly studied experimentally through various techniques such as X-ray crystallography, DTA, and NMR. It was also studied experimentally through nuclear quadrupole resonance (NQR), but this study was limited and incomplete. In this paper, we present a more detailed study of TBC through the NQR of 35Cl. Our results show that near 120 K, the onset of the CH3 groups semirotations around symmetry axis C3 takes place with an activation energy U=16.1 kJ mol−1. This intramolecular movement produces a T1 minimum near 148 K and is the dominant mechanism of the nuclear spin-lattice relaxation in phase III of this compound. In phase II of TBC, we show that there are not only methyl groups semirotations, but also semirotations of the whole molecule around a different axis from the symmetry axis C′3 (C–Cl bond) with an activation energy of E=10.4 kJ mol−1. 相似文献
128.
129.
B. Brunetti P. Candori S. Falcinelli B. Lescop G. Liuti F. Pirani F. Vecchiocattivi 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(1):21-27
A crossed beam experiment is carried out to measure the energy of electrons
emitted in Penning ionization processes by Ne*(3P2,0)–Kr
collisions. The electron energy spectra have been measured at four different
collision energies: 0.050, 0.140, 0.190, 0.460 eV. The analysis of the
results allows the separation of spin orbit contributions both in the
entrance and in the exit channels providing the related cross-section
ratios. Some theoretical considerations have been made to clarify nature and
role of interatomic potentials driving the collisions and some general
features about the role of atomic fine structure in the Penning ionization
processes. 相似文献
130.
F. Rosi C. Miliani C. Clementi K. Kahrim F. Presciutti M. Vagnini V. Manuali A. Daveri L. Cartechini B. G. Brunetti A. Sgamellotti 《Applied Physics A: Materials Science & Processing》2010,100(3):613-624
A non-invasive study has been carried out on 18 paintings by Alberto Burri (1915–1995), one of Italy’s most important contemporary painters. The study aims to demonstrate the appropriate and suitable use of portable non-invasive instrumentation for the characterization of materials and techniques found in works dating from 1948 to 1975 belonging to the Albizzini Collection. Sampling of any kind has been forbidden, in order to maintain the integrity of the paintings. Furthermore, the material heterogeneity of each single artwork could potentially result in a poorly representative sampling campaign. Therefore, a non-invasive and in situ analytical approach has been deemed mandatory, notwithstanding the complexity of modern materials and challenging data interpretation. It is the non-invasive nature of the study that has allowed for the acquisition of vast spectral data (a total of about 650 spectra including XRF, mid and near FTIR, micro-Raman and UV–vis absorption and emission spectroscopies). In order to better handle and to extrapolate the most meaningful information from these data, a statistical multivariate analysis, namely principal component analysis (PCA), has been applied to the spectral results. In particular, the possibility of combining elemental and molecular information has been explored by uniting XRF and infrared spectra in one PCA dataset. The combination of complementary spectroscopic techniques has allowed for the characterization of both inorganic and organic pigments, extenders, fillers, and binders employed by Alberto Burri. 相似文献