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Thomas R. Love 《International Journal of Theoretical Physics》1993,32(1):63-88
The Poincaré group is replaced byU(3, 2), the pseudounitary extension of the de Sitter groupSO(3, 2), as internal and space-time symmetries are combined in a geometric setting which invalidates the no-go theorems. A new model of elementary particles as vertical vectors on the principal fiber bundleU(3, 2) U(3, 2)/U(3, 1)×U(1) is introduced and their interactions via Lie bracket analyzed. The model accounts for the four known superselection rules: spin, electric charge, baryon number, and lepton number. 相似文献
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Love JC Wolfe DB Haasch R Chabinyc ML Paul KE Whitesides GM Nuzzo RG 《Journal of the American Chemical Society》2003,125(9):2597-2609
The adsorption of n-alkanethiols onto polycrystalline thin films of palladium containing a strong (111) texture produces well-organized, self-assembled monolayers. The organization of the alkane chains in the monolayer and the nature of the bonding between the palladium and the thiol were studied by contact angle measurements, optical ellipsometry, reflection absorption infrared spectroscopy (RAIRS), and X-ray photoelectron spectroscopy (XPS). The XPS data reveals that a compound palladium-sulfide interphase is present at the surface of the palladium film. The RAIR spectra, ellipsometry data, and wetting properties show that the palladium-sulfide phase is terminated with an organized, methyl-terminated monolayer of alkanethiolates. The local molecular environment of the alkane chains transitions from a conformationally disordered, liquidlike state to a mostly all-trans, crystalline-like structure with increasing chain length (n = 8-26). The intensities and dichroism of the methylene and methyl stretching modes support a model for the average orientation of an ensemble of all-trans-conformer chains with a tilt angle of approximately 14-18 degrees with respect to the surface normal and a twist angle of the CCC plane relative to the tilt plane of approximately 45 degrees. The SAMs are stable in air, although the sulfur present at the surface oxidizes in air over a period of 2-5 days at room temperature. The differences in chain organization between SAMs formed by microcontact printing and by solution deposition are also examined by RAIRS and XPS. 相似文献
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Jack D. Dunitz 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》1988,100(7):1035-1035
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Calculations of quantum mechanical probabilities and rate constants for the collinear reaction Br + HCl(ν = 2,3,4) → BrH + Cl, Br + HCl(ν < ν) were performed using hyperspherical coordinates. Removal of vibrationally excited HCl proceeds mainly by reaction to a nearly degenerate HBr state. Processes for which a large change in the internal enery occurs have low probabilities. 相似文献
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