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For a given two-dimensional surface μ, we studi invariants for oriented links in μ×[0,1] which generalize the two-variable
HOMFLY polynomials when μ is the 2-disk. These invariants are connected to multiparameter quantum groups whose special properties
are discussed.
Si studiano gli invarianti dei nodi in spazi del tipo μ×[0,1], dove μ è una superficie. Questi invarianti generalizzano gli
invarianti di HOMFLY.
(Conferenza tenuta dal Prof. P. Cotta-Ramusino il 16 maggio 1991) 相似文献
(Conferenza tenuta dal Prof. P. Cotta-Ramusino il 16 maggio 1991) 相似文献
5.
CuPc molecules adsorbed on Au(1 1 0)-(1 × 2): growth morphology and evolution of valence band states
Fabrizio Evangelista A. RuoccoValdis Corradini M.P. DonzelloCarlo Mariani Maria Grazia Betti 《Surface science》2003,531(2):123-130
We present the growth morphology, the long-range ordering, and the evolution of the valence band electronic states of ultrathin films of copper phthalocyanine (CuPc) deposited on the Au(1 1 0)-(1 × 2) reconstructed surface, as a function of the organic molecule coverage. The low energy electron diffraction patterns present a (5 × 3) reconstruction from the early adsorption stages. High-resolution UV photoelectron spectroscopy data show the disappearance of the Au surface states related to the (1 × 2) reconstruction, and the presence of new electronic features related to the molecule-substrate interaction and to the CuPc molecular states. The CuPc highest occupied molecular orbital gradually emerges in the valence band, while the interface electronic states are quenched, upon increasing the coverage. 相似文献
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Maurizio Serva 《Journal of statistical physics》1998,91(1-2):31-45
The model considered is a d=2 disordered Ising system on a square lattice with nearest neighbor interaction. The disorder is induced by layers (rows) of spins, randomly located, which are frozen in an antiferromagnetic order. It is assumed that all the vertical couplings take the same positive value J
v, while all the horizontal couplings take the same positive value J
h. The model can be exactly solved and the free energy is given as a simple explicit expression. The zero-temperature entropy can be positive because of the frustration due to the competition between antiferromagnetic alignment induced by the quenched layers and ferromagnetic alignment due to the positive couplings. No phase transition is found at finite temperature if the layers of frozen spins are independently distributed, while for correlated disorder one finds a low-temperature phase with some glassy properties. 相似文献
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Summary This paper reports the results of a study on the use of a new polymer-based, strong anion-exchange, stationary phase for rapid
and selective separation of carbohydrates and related compounds by high-pH, anion-exchange chromatography with pulsed amperometric
detection. The new adsorbent has been obtained by direct nitration of 2.8 μm, spherical non-porous highly cross-linked, styrene-divinylbenzene
copolymer beads, followed by reduction of superficially introduced nitro groups with nascent hydrogen and quaternization of
the resultant amino groups with iodomethane. It is reported that by optimizing the ionic strength of the mobile phase, columns
packed with the new anion-exchanger can be successfully employed to separate, either in isocratic or gradient elution mode,
oligosaccharides, positional isomers of gluco-disaccharides, as well as uronic acids and sugar monophosphates. 相似文献
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Francesco Ghetti Giuliano Colombetti Francesco Lenci Enzo Campani Erseo Polacco Maurizio Quaglia 《Photochemistry and photobiology》1985,42(1):29-33
Abstract— The spectroscopic characterization of the photoreceptor pigment is one of the main questions in the study of the photosensory transduction chains in photomotile microorganisms. One of the possible techniques that can be used is in vivo microspectrofluorometry. By means of a tunable dye-laser microspectrofiuorometer developed by us, we have investigated some of the spectroscopic properties of the photoreceptor pigment of the green flagellate Euglena gracilis. The in vivo fluorescence excitation spectrum has been determined and the fluorescence quantum yield has been measured. The results show that flavins are indeed present in the paraflagellar body of E. gracilis and that their fluorescence quantum yield is much lower than that of a free flavin. An estimate of the order of magnitude of the rate constants for primary molecular reactions is tentatively given. 相似文献