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991.
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994.
The generalized 2-D problem of a half-infinite interfacial electrode layer between two arbitrary piezoelectric half-spaces
is studied. Based on the Stroh formalism, exact expressions for the Green’s functions of a line force, a line charge and a
line electric dipole applied at an arbitrary point near the electrode edge, were prsented, respectively. The corresponding
solution for the intensity factors of fields were also obtained in an explicit form. These results can be used as the foundational
solutions in boundary element method (BEM) to solve more complicated fracture problems of piezoelectric composites.
Foundation item: the Alexander von Humboldt Foundation of Germany
Biography: GAO Cun-fa, Associate Professor, Doctor, E-mail: cfgao@yahoo.com 相似文献
995.
Polarizable continuum models (PCMs) are a widely used family of implicit solvent models based on reaction-field theory and boundary-element discretization of the solute/continuum interface. An often overlooked aspect of these theories is that discretization of the interface typically does not afford a continuous potential energy surface for the solute. In addition, we show that discretization can lead to numerical singularities and violations of exact variational conditions. To fix these problems, we introduce the switching/Gaussian (SWIG) method, a discretization scheme that overcomes several longstanding problems with PCMs. Our approach generalizes a procedure introduced by York and Karplus [J. Phys. Chem. A 103, 11060 (1999)], extending it beyond the conductor-like screening model. Comparison to other purportedly smooth PCM implementations reveals certain artifacts in these alternative approaches, which are avoided using the SWIG methodology. The versatility of our approach is demonstrated via geometry optimizations, vibrational frequency calculations, and molecular dynamics simulations, for solutes described using quantum mechanics and molecular mechanics. 相似文献
996.
Two silylene nickel carbonyl complexes of composition L·Ni(CO)(3) (1) {L = PhC(NtBu)(2)SiCl} and L'(2)·Ni(CO)(2) (2) { L' = RSiCl(2), R = (1,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene)} were prepared by reacting 1 equivalent of Ni(CO)(4) with 1 equivalent of heteroleptic chlorosilylene L for 1 and with 2 equivalents of carbene stabilized dichlorosilylene L' for 2 in toluene at room temperature. Both complexes 1 and 2 were characterized by single-crystal X-ray analysis, NMR and IR spectroscopy, EI-MS spectrometry, and elemental analysis. 相似文献
997.
Ricardo Rodríguez-Palacios Marisol Reyes-Lezama Lucila Márquez-Pallares Ana Adela Lemus-Santana Obdulia Sánchez-Guadarrama Herbert Höpfl Noé Zúñiga-Villarreal 《Polyhedron》2010
Reaction of ReBr(CO)5 with Li[Ph2P(O)NP(O)Ph2] afforded the cryptate Li[Re2(CO)6{μ-Ph2P(O)NP(O)Ph2-κ2O,O’}3]; whereas K[Ph2P(O)NP(O)Ph2] reacted with ReBr(CO)5 to give K[Re2(CO)6{μ-Ph2P(O)NP(O)Ph2-κ2O,O′}{Ph2P(O)NP(O)Ph2-κ2O,O′}2]. Other chalcogen ligands’ salts M[Ph2P(E)NP(E)Ph2], E = Se and S, M = K and Li gave dirhenium carbonyls with bromido and Ph2P(E)NP(E)Ph2, E = Se or S bridges upon reaction with ReBr(CO)5. 相似文献
998.
999.
Bacterial adhesion to epithelial cells is a key step in infections, allowing subsequent colonization, invasion and internalization of pathogens into tissues. Anti-adhesive agents are therefore potential prophylactic tools against bacterial infections. The range of anti-adhesive compounds is largely confined to carbohydrate analogues. Tannins are generously recognized as potent antimicrobials, but little data exist on their anti-adherence potency. Using a model for mucosal pathogenesis with labeled group A-streptococci (GAS) and human laryngeal HEp-2 cells, a series of flavan-3-ols (epicatechin, epigallocatechin, epigallocatechin-3-O-gallate) and highly purified and chemically characterized proanthocyanidin samples including procyanidins based on epicatechin, catechin or 'mixed' constituent flavanyl units, prodelphinidins made up of (epi)gallocatechin monomeric unts as well as oligomers possessing A-type units in their molecules was evaluated for anti-adhesive effects. Reduced microbial adherence was observed exclusively for prodelphinidins, suggesting that pyrogallol-type elements, i.e., (epi)gallocatechin units are important structural features. This is the first report on structure-activity relationships regarding the anti-adhesive potency of proanthocyanidins. In addition, the structures of the first chemically defined proanthocyanidins from Pelargonium sidoides are disclosed. 相似文献
1000.
Kinetics of the reactions of allylsilanes (1) and silyl enol ethers (2) with benzhydrylium ions (3) were studied by UV-vis spectroscopy in dichloromethane at 20 °C. The less than three times higher reaction rates of the tris(trimethylsilyl)silyl compounds in comparison to the corresponding trimethylsilyl compounds indicate that the previously reported strong electron-donating effect of the supersilyl group operates only in the α-position and not in the β-position. 相似文献