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51.
Benoit Perthame Athanasios E. Tzavaras 《Archive for Rational Mechanics and Analysis》2000,155(1):1-48
For scalar conservation laws, the kinetic formulation makes it possible to generate all the entropies from a simple kernel.
We show how this concept replaces and simplifies greatly the concept of Young measures, avoiding the difficulties encountered
when working in L
p
. The general construction of the two kinetic functions that generate the entropies of 2 × 2 strictly hyperbolic systems
is also developed here. We show that it amounts to building a “universal” entropy, i.e., one that can be truncated by a “kinetic
value” along Riemann invariants. For elastodynamics, this construction can be completed and specialized using the additional
Galilean invariance. This allows a full characterization of convex entropies. It yields a kinetic formulation consisting of
two semi-kinetic equations which, as usual, are equivalent to the infinite family of all the entropy inequalities.
Accepted May 29, 2000?Published online November 16, 2000 相似文献
52.
Athanasios Deligiannis 《manuscripta mathematica》2000,102(2):251-261
We construct for all topological space X and all n∈N a natural section e
n
X
:G
n
X→G
n
G
n
X of the Ganea projection :G
n
G
n
X→G
n
X and show that the triple (G
n
,g
n
,e
n
) is a comonad on Top
*.
Received: 6 March 2000 相似文献
53.
54.
Hoang Tuy Saied Ghannadan Athanasios Migdalas Peter Värbrand 《Mathematical Programming》1996,72(3):229-258
We show that the production-transportation problem involving an arbitrary fixed number of factories with concave production
cost is solvable in strongly polynomial time. The algorithm is based on a parametric approach which takes full advantage of
the specific structure of the problem: monotonicity of the objective function along certain directions, small proportion of
nonlinear variables and combinatorial properties implied by transportation constraints. 相似文献
55.
We devise Lyapunov functionals and prove uniform L1 stability for one-dimensional semilinear hyperbolic systems with quadratic nonlinear source terms. These systems encompass a class of discrete velocity models for the Boltzmann equation. The Lyapunov functional is equivalent to the L1 distance between two weak solutions and non-increasing in time. They result from computations of two point interactions in the phase space. For certain models with only transversal collisional terms there exist generalizations for three and multi-point interactions. 相似文献
56.
Hoang Tuy Saied Ghannadan Athanasios Migdalas Peter Värbrand 《Journal of Global Optimization》1995,6(2):135-151
We prove that the Minimum Concave Cost Network Flow Problem with fixed numbers of sources and nonlinear arc costs can be solved by an algorithm requiring a number of elementary operations and a number of evaluations of the nonlinear cost functions which are both bounded by polynomials inr, n, m, wherer is the number of nodes,n is the number of arcs andm the number of sinks in the network.On leave from Institute of Mathematics, P.O. Box 631, Bo Ho, Hanoi, Vietnam. 相似文献
57.
Methyl esters of N-(3,5-dinitrobenzoyl)-amino acids have been used as chiral solvating agents to induce NMR spectral nonequivalence between the enantiomers of a broad array of solutes. 相似文献
58.
The ability of vesicle-coated silica to aid the extraction of organic compounds from water prior to liquid chromatographic analysis is presented for the first time. The method is based on the formation of silica supported cationic multi-lamellar vesicles of gemini surfactants inherently ensuring the presence of hydrophilic and hydrophobic sites for the partitioning of analytes bearing different properties. Method development is illustrated by studying the adsolubilization of UV absorbing chemicals from swimming pool water. Due to the requirement for external energy input (intense shearing) a method based on solid-phase dispersion (SPD) was applied producing better results than off-line solid-phase extraction (SPE). Meticulous investigation of the experimental parameters was conducted in order to elucidate the mechanisms behind the proposed extraction pattern. Analyte recoveries were quantitative under the optimum experimental conditions offering recoveries higher than 96% with RSD values below 5%. 相似文献
59.
Reaction of 1-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfonyl}acetone with sodium hydroxide with or without zinc gave 1-(2-nitrophenyl)(1H-pyrrol-2-ylsulfonyl)methane by a Truce-Smiles type of transformation and 1-(2-nitrophenyl)-2-methylsulfonylpyrrole by deacetylation. Similar treatment of 1-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfinyl}acetone gave only 1-(2-nitro-phenyl)(1H-pyrrol-2-ylsulfinyl)methane. 1-{[1-(2-Nitrophenyl)-1H-pyrrol-2-yl]sulfanyl}acetone, 2-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfanyl}-1-phenyl-ethan-1-one or 2-{[1-(2-nitrophenyl)-1H-pyrrol-2-yl]sulfanyl}acetonitrile were reductively cyclised with sodium borohydride and 5% palladium-on-carbon into 6-methyl(or phenyl)-5,6-dihydro-7H-pyrrolo[1,2-a][3.1.6]benzothiadiazocin-7-ol or 6-amino-5H-pyrrolo[1,2-a][3.1.6]benzothiadiazocine-7-oxide, respectively. 相似文献
60.
Petros Giastas Athanasios Papakyriakou George Tsafaras Socrates J. Tzartos Marios Zouridakis 《Molecules (Basel, Switzerland)》2022,27(14)
The β3 subunit of nicotinic acetylcholine receptors (nAChRs) participates in heteropentameric assemblies with some α and other β neuronal subunits forming a plethora of various subtypes, differing in their electrophysiological and pharmacological properties. While β3 has for several years been considered an accessory subunit without direct participation in the formation of functional binding sites, recent electrophysiology data have disputed this notion and indicated the presence of a functional (+) side on the extracellular domain (ECD) of β3. In this study, we present the 2.4 Å resolution crystal structure of the monomeric β3 ECD, which revealed rather distinctive loop C features as compared to those of α nAChR subunits, leading to intramolecular stereochemical hindrance of the binding site cavity. Vigorous molecular dynamics simulations in the context of full length pentameric β3-containing nAChRs, while not excluding the possibility of a β3 (+) binding site, demonstrate that this site cannot efficiently accommodate the agonist nicotine. From the structural perspective, our results endorse the accessory rather than functional role of the β3 nAChR subunit, in accordance with earlier functional studies on β3-containing nAChRs. 相似文献