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891.
Bruno Franchi 《Mathematische Nachrichten》1986,127(1):25-50
In this paper, we prove a trace theorem for anisotropic weighted Sobolev spaces in a cube Q naturally associated to a class of degenerate elliptic operators. The fundamental property of this class is the existence of a suitable metric d which is “natural” for the operators. The basic tool of the proof is a representation formula obtained via suitable non-euclidean translations closely fitting the geometry of the d-balls. In a more particular situation, we construct a right inverse of the trace operator and we describe the compatibility conditions on the edges of Q. 相似文献
892.
We have performed a series of electroreflectance, photoluminescence, and electric-field-modulated photoluminescence experiments
to characterize the strain-induced electric fields in (111)B InGaAs/AlGaAs quantum well p-i-n diode structures. A 180° phase
change in the lineshapes of electroreflectance spectra of these samples determines when the quantum well is biased to flatband.
Using this bias and a depletion model for the diode, the polarization field in the quantum well can be determined. Contrary
to expectations, this polarization field increases significantly with increasing temperature. In addition, at fixed temperature,
the quantum well transition energies red-shift with increasing excitation intensity when excited by photons of energy higher
than the lowest quantum well transition but lower than the AlGaAs diode's bandgap. When excited with photons of energy greater
than the AlGaAs bandgap, the transition energy first red shifts then blue shifts with increasing excitation intensity. 相似文献
893.
Bruno Poizat 《Order》1985,2(3):323-325
Résumé Je caractérise les combinaisons booléennes de parties finales d'un ordre partiel P au moyen d'une limitation de la façon dont elles peuvent alterner sur les chaînes de P.
I characterize the Boolean combinations of final segments of an ordered set by restricting the way they alternate on the chains of P.相似文献
894.
A careful discussion of the concept of conditional event leads to a sensible use of frequency data as conditional probabilities: as a by-product, the well-known ‘paradoxes’ arising from the so-called confounding effect are avoided. 相似文献
895.
We study the class of structures formed by all the polygons over a given monoid, which is equivalent to the study of the varieties in a language containing only unary functions. We collect and amplify previous results concerning their stability and superstability. Then we characterize the regular monoids for which all these polygons are ω-stable; the question about the existence of a non regular monoid with this property is left open. 相似文献
896.
Costa Riberiro P. Bruno A.C. Saboia e Silva P.L. Hall Barbosa C.R. Parente Ribeiro E. Costa Monteiro E. Fonseca Costa A. 《IEEE transactions on bio-medical engineering》1992,39(8):818-824
We discuss the use of magnetocardiography to detect reentry currents in cardiac flutter and fibrillation. The magnetic field produced by induced atrial flutter was measured in isolated rabbit hearts. A moving dipole model is proposed to treat the experimental data and to locate the reentry path. 相似文献
897.
In this paper, we study a rational function which plays an important role in several problems of interest (eigenvalue problems, linear control theory, ... ). Our main interest is to determine zero-free regions. We also derive upper and lower bounds for this function. 相似文献
898.
The possibility of performing in proximity of the Earth experiments to test the predictions of general relativity for the trajectories of particles and photons in weak gravitational fields is studied. Three experiments are analyzed, all based on optical detection methods. The first experiment would allow to detect the tidal acceleration using a freely-falling Michelson interferometer. In a second experiment, based on laser-ranging methods, the relativistic correction to the classical gravity acceleration could be detected. Finally, the possibility of detecting light deflection induced by space curvature in an optical cavity with high-reflectivity mirrors is discussed. 相似文献
899.
Hans-Dietrich Stachel Bruno Wiesend Christine Kreiner 《Journal of heterocyclic chemistry》1985,22(5):1413-1418
The epimeric bromoghydrins 13/14 as well as their ethers 5/6 rearrange in the presence of silver ions to the 5-hydroxypyridones 15 or their ketals 9 respectively. with the bromohydrin ethers 5/6a and b this transformation is effected also with sodium methoxide. Under these reaction conditions the ring expansion is presumend ot proceed via bicyclic aziridines of which 7 could be issolated, The N-methylated compounds 5c/6c which cannot react likewise, form with sodium methoxide the 6-methoxypyridone 12 . 相似文献
900.
Bruno Putman Paul Van der Meeren Jan Vanderdeelen 《Particle & Particle Systems Characterization》1997,14(2):73-78
In order to analyse the output data of centrifugal photosedimentation experiments using CONTIN software, a mathematical model has been derived. This model is based on Fick's second law and describes the sedimentation behaviour of monomodal particles in a centrifugal field: it predicts that the extinction at the detection point decays exponentially until the particles are sedimented past the detection point, which gives a sharp drop of the curves to the baseline. In practice, however, a more fluently decaying profile was obtained. Simulations revealed that the polydispersity of the sample was responsible for this behaviour. When centrifugal photosedimentation data for effective monomodal and bimodal samples of fairly monodispersed PMMA lattices were analysed with CONTIN, using the model proposed, accurate particle size distributions were obtained, provided that the sample cell was completely filled. This was imperative in order to minimize the deviations of the practical application as compared with the theoretical model. 相似文献