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111.
2-D fracture dynamics' problems for elastic bimaterials with cracks located at the bonding interface under the oblique time harmonic wave are considered in the study. The system of boundary integral equations for displacements and tractions is derived from Somigliana identity taking the contact interaction of the opposite crack faces into account. For the numerical solution the collocation method with piecewise constant approximation is used. The numerical results are obtained for various values of the angle of the wave incidence and the wave frequency taking the friction effects into account. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
112.
Marboutin L Petitjean H Xerri B Vita N Dupeyrat F Flament JP Berthomieu D Berthomieu C 《Angewandte Chemie (International ed. in English)》2011,50(35):8062-8066
Vibrations of the metal active site of the Cu,Zn-superoxide dismutase enzyme were analyzed by far-infrared difference spectroscopy and theoretical normal mode calculation. Both electrochemically triggered Cu(I) and Cu(II) redox states show well-defined infrared vibrational modes, notably modes of the histidine ligands, the Cu(II) -His(61) -Zn(II) bridge and of the water pseudo-ligand. 相似文献
113.
Andrea Di Vita 《Central European Journal of Physics》2012,10(1):86-95
Metal hydrides are solutions of hydrogen in a metal, where phase transitions may occur depending on temperature, pressure
etc. We apply Le Chatelier’s principle of thermodynamics to a particular phase transition in TiH
x
, which can approximately be described as a second-order phase transition. We show that the fluctuations of the order parameter
correspond to fluctuations both of the density of H+ ions and of the distance between adjacent H+ ions. Moreover, as the system approaches the transition and the correlation radius increases, we show -with the help of statistical
mechanics-that the statistical weight of modes involving a large number of H+ ions (‘collective modes’) increases sharply, in spite of the fact that the Boltzmann factor of each collective mode is exponentially
small. As a result, the interaction of the H+ ions with collective modes makes a tiny suprathermal fraction of the H+ population appear. Our results hold for similar transitions in metal deuterides, too. A violation of an -insofar undisputed-upper
bound on hydrogen loading follows. 相似文献
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119.
Antonio Cardone Carmela Martinelli Vita Pinto Francesco Babudri Maria Losurdo Giovanni Bruno Pinalysa Cosma Francesco Naso Gianluca M. Farinola 《Journal of polymer science. Part A, Polymer chemistry》2010,48(2):285-291
Fully fluorinated arylenevinylene polymers have been synthesized via a methodology based on the Stille cross‐coupling reaction and characterized by FTIR spectroscopy and MALDI‐TOF mass spectrometry. Investigation of thin film properties by cyclic voltammetry and ellipsometry shows that complete substitution of hydrogen atoms with fluorine atoms on the conjugated backbone of the poly(arylenevinylene)s results in a strong increase of the band gap. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 285–291, 2010 相似文献
120.
Jason Nguyen William Wonderly Tatum Tauscher Robin Harkins Francesco Vita Giuseppe Portale 《Liquid crystals》2013,40(12):1754-1764
We have previously demonstrated that the incorporation of lateral methyl groups on oxadiazole-based liquid crystals leads to relatively low-temperature cybotactic nematic phases which, in some cases, supercool to room temperature. We report here the synthesis and phase behaviour of related compounds that possess lateral halogen groups and in some cases, lateral methyl groups as well. Derivatives with three lateral substituents (one halogen and two methyl groups) in a specific pattern supercool in the nematic phase to room temperature. As was the case with the previously reported trimethylated derivatives, the low-temperature nematic phase is glassy in nature. Two of the new trisubstituted derivatives (with bromo and chloro groups) remain in the nematic phase upon subsequent heating until transitioning to the isotropic phase indicating that the low-temperature nematic phase may be more stable than that shown by the trimethylated analogue. Preliminary X-ray diffraction analysis confirms the presence of a tilted cybotactic nematic phase. In addition, the splitting observed in the wide-angle scattering feature is indicative of enhanced local biaxial packing. 相似文献