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991.
The detrimental oxidative reactions which occur in thermoplastic polyurethane elastomers based on aromatic isocyanate monomers during irradiation with polychromatic light (λ > 300 nm) may be accounted for by the interference of two mechanisms. The first mechanism, observed at λ < 330–340 nm, involves a photo-Fries rearrangement. The second mechanism is a photo-induced hydroperoxidation. The photo-Fries products exhibit an anti-ultraviolet effect and partially inhibit the photo-induced oxidation. In contrast to aromatic polyurethane elastomers, aliphatic models exposed to ultraviolet light undergo a photo-induced oxidation which is independent of the excitation wavelength. 相似文献
992.
Félicité Misago Jacques Walrand Ghislain Blanquet 《Journal of Molecular Spectroscopy》2006,237(1):46-52
Using a tunable diode-laser spectrometer, N2-broadening coefficients have been measured for 15 lines in the ν3 band of C32S2 at room and low temperatures (298, 273.2, 248.2, 223.2, and 198.2 K). These lines with J values ranging from 2 to 62 are located in the spectral range 1519-1545 cm−1. The collisional widths are obtained by fitting each measured spectral line with a Voigt and a Rautian lineshape model and for a few lines we also used a Galatry model. From these results, we have determined the n parameter of the temperature dependence of each broadening coefficient. A semiclassical calculation of these broadenings has been performed by considering in addition to the main electrostatic quadrupole-quadrupole interaction an anisotropic dispersion contribution leading to satisfactory results at all temperatures and providing the n temperature dependence parameter in good agreement with the experimental determination. 相似文献
993.
994.
Jacques Lalevée Ali Dirani Mohamad El‐Roz Xavier Allonas Jean Pierre Fouassier 《Journal of polymer science. Part A, Polymer chemistry》2008,46(9):3042-3047
In this article, germanes are presented as new coinitiators for both radical and cationic photopolymerization processes. For the free radical polymerization process, the newly proposed structures are characterized by efficiencies similar or better than the reference amine. Germyl radicals are also found to be excellent initiators for free radical promoted cationic photopolymerization (FRPCP) of an epoxy resin. The associated reactivity is even better under air. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3042–3047, 2008 相似文献
995.
996.
997.
We complete the proof that the two-dimensional Hubbard model at half- filling is not a Fermi liquid in the mathematically precise sense of Salmhofer, by establishing a lower bound on a second derivative in momentum of the first nontrivial self-energy graph.submitted 20/12/04, accepted 10/12/05 相似文献
998.
999.
1000.
Kazuchika Ohta Takuya Watanabe Satoshi Tanak Testsuya Fujimoto Iwao Yamamoto Pierre Bassoul Nathalie Kucharczyk Jacques Simon 《Liquid crystals》1991,10(3):357-368
Octakis(alkyloxyphenyl)-phthalocyanine derivatives ((CnOph)8PcH2 n = 8, 10 12 and 18), their corresponding copper (II) complexes ((CnOph)8PcCu, n = 10, 12 and 18) and octakis(2-ethylhexyl)-PcH2 have been synthesized and their mesomorphic properties characterized. (CnOph)8PcH2, (n = 12 and 18) exhibit hexagona disordered columnar mesophases whereas (CnOph)8PcCu (n = 12 and 18) yields a rectangular disordered columnar liquid crystal. An alkylphenyl-oxymethyl derivative, (C12phOCH2)8PcH2, was synthesized to determine the influence of the connecting link between the side chains and the phthalocyanine macrocycle on the mesomorphic properties. 相似文献