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1.
Marcel Oliver 《Theoretical and Computational Fluid Dynamics》1997,9(3-4):311-324
The so-called lake equations arise as the shallow-water limit of the rigid-lid equations—three-dimensional Euler equations
with a rigid-lid upper boundary condition—in a horizontally periodic basin with bottom topography. We prove an a priori estimate in the Sobolev space H
m
for m≥ 3 which shows that a solution to the rigid-lid equations can be approximated by a solution of the lake equations for an
interval of time which can be estimated in terms of the initial deviation from a columnar configuration and the magnitude
of the initial data in H
m
, the gradient of the bottom topography in H
m+1
, and the aspect ratio of the basin. In particular, any solution to the lake equations remains close to some solution of the
rigid-lid equations for an interval of time that can be made arbitrarily large by choosing the aspect ratio of the basin small.
Received 10 October 1996 and accepted 15 May 1997 相似文献
2.
Marcel Crabbé 《Comptes Rendus Mathematique》2004,338(6):433-436
We investigate the notion of substitution in an abstract way, without defining it explicitly. We single out the essential features of the operation of performing a substitution in order to define a concept of substitutive structure, called logos. We then prove a completeness theorem making precise and justifying the intuition that formulas true for the usual substitution can be proved from the logos axioms only. To cite this article: M. Crabbé, C. R. Acad. Sci. Paris, Ser. I 338 (2004). 相似文献
3.
Marcel Erné 《Order》1991,8(2):159-173
We introduce a special type of order-preserving maps between quasiordered sets, the so-called cut-stable maps. These form the largest morphism class such that the corresponding category of quasiordered sets contains the category of complete lattices and complete homomorphisms as a full reflective subcategory, the reflector being given by the Dedekind-MacNeille completion (alias normal completion or completion by cuts). Suitable restriction of the object class leads to the category of separated quasiordered sets and its full reflective subcategory of completely distributive lattices. Similar reflections are obtained for continuous lattices, algebraic lattices, etc. 相似文献
4.
The syntheses of two rigid organic molecular rods bearing a nitronyl-nitroxide radical and a terminal nitrogen-based functionality like a pyridine or a cyano group are reported. Both new paramagnetic molecules are fully characterized, including crystal structure analysis. Furthermore their magnetic behaviours in the crystalline state are investigated and their spin concentration corroborate their excellent purity. While the pyridine functionalized rod is synthesized by converting the corresponding benzaldehyde to the phenyl-nitronyl-nitroxide radical, the synthesis of the cyano functionalized rod demonstrates the accessibility of highly sophisticated spin-labelled molecules via cross-coupling reaction with a meta-iodo-phenyl-nitronyl-nitroxide moiety. 相似文献
5.
6.
Marek Pękała Jan Mucha Benedicte Vertruyen Rudi Cloots Marcel Ausloos 《Journal of magnetism and magnetic materials》2006
Samples of La0.7Ca0.3Mn1−xGaxO3 with x=0, 0.025, 0.05 and 0.10 were prepared by standard solid-state reaction. They were first characterized chemically, including the microstructure. The magnetic properties and various transport properties, i.e. the electrical resistivity, magnetoresistivity (for a field below 8 T), thermoelectric power and thermal conductivity measured each time on the same sample, are reported. The markedly different behaviour of the x=0.1 sample from those with a smaller Ga content, is discussed. The dilution of the Mn3+/Mn4+ interactions with Ga doping considerably reduces the ferromagnetic double exchange interaction within the manganese lattice leading to a decrease of the Curie temperature. The polaron binding energy varies from 224 to 243 meV with increased Ga doping. 相似文献
7.
Marcel Erné 《Algebra Universalis》1988,25(1):290-321
By a result of Pigozzi and Kogalovskii, every algebraic latticeL having a completely join —irreducible top element can be represented as the lattice L() of equational theories extending some fixed theory . Conversely, strengthening a recent result due to Lampe, we show that such a representationL=L() forcesL to satisfy the following condition: if the top element ofL is the join of a nonempty subsetB ofL then there are elementsb..., B such thata=(... (((b1 a) b2) a) ... bn) a for alla L. In presence of modularity, this equation reduces to the identitya=(a b1) ... (a bn). Motivated by these facts, we study several weak forms of distributive laws in arbitrary lattices and related types of prime elements. The main tool for applications to universal algebra is a generalized version of Lampe's Zipper Lemma.Presented by Ralph Freese. 相似文献
8.
The primary amino group of 3-(2-aminoethyl)-3-(4-chlorophenyl)-2,3-dihydro-1H-isoindol-1-one ( 1 ) was acylated with acetyl chloride, benzoyl chloride and phenyl acetyl chloride to form the amides 2a -c, respectively. These were cyclized in phosphorus oxychloride to give the 1-substituted-4a-(4-chlorophenyl)-4,4a-dihydropyrimido [6,1-a]isoindol-9(3H)-ones 3a-c . Heating of 1 in formic acid lead to the formation of 4a-(4-chlorophenyl)-4,4a-dihydropyrimido[6,1-a]isoindol-9(3H) -one (3d) . Heating of 1 in the presence of phosgene lead to the formation of 4a-(4-chlorophenyl)-2,3,4,4a-tetrahydropyrimido[6,1-a]isoindole-1, 9-dione (4). 相似文献
9.
Henri-Edouard Audier Marcel Fetizon Yannik Henry Thierry Prange 《Journal of mass spectrometry : JMS》1976,11(10):1047-1055
The fragmentation mechanisms of oxazole have been studied in detail on using various experimental techniques (refocusing of metastable ions, deuteration, AP measurements) and by theoretical calculations. 相似文献
10.
The temperature dependence of the 35Cl nuclear quadrupole resonance spectra of tetrachloro-o-benzoquinone (TOB) is reported. An analysis of the change in line multiplicities suggests that TOB undergoes three phase changes in going from 77 to 330 K. The transition temperatures have been determined. 相似文献