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91.
We show that suitable upper estimates of the heat kernel are sufficient to imply the L
p
boundedness of several families of operators associated with the Schr?dinger group in various situations. This generalizes
results by Sj?strand and others in the Euclidean case, and by Alexopoulos in the case of Lie groups and Riemannian manifolds.
RID="*"
ID="*"Research partially supported by the European Commission (European TMR Network "Harmonic Analysis" 1998-2001, Contract
ERBFMRX-CT97-0159). 相似文献
92.
Brownstein SK Ding J Robertson G Roovers J Enright G 《The Journal of organic chemistry》2002,67(3):663-667
A new example of magnetic nonequivalence of chemically equivalent atoms is identified from the proton and carbon resonance spectra of 9,10-di(9,9-dioctylfluorenyl)anthracene with the aid of its conformation in the crystalline state. Molecular modeling suggests that it has a similar conformation in solution. 相似文献
93.
J. Devaux P. Godard J. P. Mercier R. Touillaux J. M. Dereppe 《Journal of Polymer Science.Polymer Physics》1982,20(10):1881-1894
The structure of the four-component copolyester resulting from the exchange reaction between molten bisphenol-A polycarbonate and poly(butylene terephthalate) is analyzed as a function of the reaction time by infrared and nuclear magnetic resonance spectroscopy. By applying a statistical method developed earlier, the mean chain length of the various sequences as well as the degree of randomness is computed. The exchange reaction leads initially to the formation of a block copolyester with reduced solubility. As the reaction proceeds, a soluble random copolycondensate is progressively formed. 相似文献
94.
The Mg(0001) face is subjected to oxygen adsorption from 0 to 103 L. Three characteristic stages of oxygen adsorption are detected from 0 to 10 L. The AES signal of clean Mg decays exponentially against exposure with slopes α ai such that αA2 (0.75 → 3 L) >αA1 (0 → 0.75 L)>αA3 (3 → 10 L). For increasing exposures, they correspond to: (1) a clear (1 × 1)-Mg(0001), (2) a diffuse (1 × 1)-Mg(0001) and (3) a (1 × 1) with a weaker (1 × 1)-R30°-MgO(111) LEED patterns, respectively. At the end of the third stage, a supplementary ( pattern is observed. In ELS, a very fast intensity decrease of energy loss peaks due to surface and bulk plasmon excitations of the clean metal is recorded during the first stage. The energy loss peak due to the oxidized surface plasmon excitation reaches a maximum intensity at the end of the second stage. Energy loss peaks to be attributed to excitations in bulk MgO appear during the third stage. The work function of the sample decreases and shows a minimum around 6 L, and then slowly increases. Beyond 10 L, a logarithmic relation between oxide thickness and exposure seems to exist. These results are interpreted by the following sequential processes: stage 1: random oxygen chemisorption followed by oxygen incorporation (αA1); stage 2: assembling into islands and lateral island growth (αA2); stage 3: oxide formation (αA3) and stage 4: oxide thickening. Lattice models describing these processes are proposed and discussed. The influence of surface roughness on the results is emphasized. 相似文献
95.
Claude Delmas Francis Menil Gilles Le Flem Claude Fouassier Paul Hagenmuller 《Journal of Physics and Chemistry of Solids》1978,39(1):51-53
A Mössbauer study of the dimensionality of magnetic interactions in the layer oxide LiCr0.99Fe0.01O2 shows a 2-D behaviour. 相似文献
96.
Guy Solladié Christine Greck Gilles Demailly Arlette Solladié-Cavallo 《Tetrahedron letters》1982,23(48):5047-5050
It is shown that reductions of β-ketosulfoxides of identical chirality (R) at sulfur, lead to reduction products of opposite stereochemistry according to the reducing agent used. The high enantiomeric excesses obtained (80 to 100%) provide a general route to both enantiomers of methylcarbinols from the corresponding esters. 相似文献
97.
Gilles Pisier 《Acta Mathematica》1983,151(1):181-208
98.
Gilles Godefroy 《Israel Journal of Mathematics》1983,44(1):61-74
We show that ifE is a non-reflexive Banach lattice, there exists for everyn a dual of finite even order ofE which contins isometicallyl
n
/l
. We show that itE is a Banach lattice which is isometric to the dual of a Banach spaceX, then the order intervals are σ (E, X)-compact. We prove then that under various conditions, a Banach lattice which is a dual as a Banach space, is a dual as a
Banach lattice. In particular, this is true when the predual ofE is unique.
相似文献
99.
Jean-Louis Tassoul Gilles Aubin 《Journal of Mathematical Analysis and Applications》1974,45(1):116-126
This paper deals with finite-amplitude axisymmetric disturbances in a self-gravitating fluid column of finite radius R. It is shown that the cutoff wavelength λnl above which gravitational breakup occurs now depends on the relative amplitude of the initial perturbation. Actually, for small-but finite-amplitude disturbances, , where λl ( = 5.8898R) designates the cutoff wavelength predicted in the linear approximation. 相似文献
100.
The perturbation of the racemic equilibrium of luminescent D3 lanthanide(III) complexes by added chiral agents, such as amino acids, may be a useful technique for determining the absolute configuration of the added species. It is shown in this work, however, that simple interpretation of the equilibrium shift of racemic tris-terdentate complexes of Tb(III) with 2,6-pyridine-dicarboxylate by amino acids, as measured by the sign of the resultant circularly polarized luminescence (CPL) in terms of specific structural characteristics is not possible. CPL results for a number of derivatized amino acids are also presented, and some insights into the nature of the chiral discriminatory forces that might be exploited in this kind of study are discussed. 相似文献