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51.
Vassilis N. Stathopoulos Vassiliki C. Belessi Athanasios K. Ladavos 《Reaction Kinetics and Catalysis Letters》2001,72(1):49-55
The catalytic combustion of methane with stoichiometric amounts of oxygen to CO2 and H2O has been studied over samarium based high surface area perovskite type oxides SmFe1-xAlxO3 (x=0.00, 0.50 0.95) prepared via a new sol-gel method. A comparison to other lanthanum perovskites prepared by the ceramic method shows higher catalytic activity for SmFeO3 and SmFe0.5Al0.5O3 samples. 相似文献
52.
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
53.
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
54.
We consider the wave equation with a focusing cubic nonlinearity in higher odd space dimensions without symmetry restrictions on the data. We prove that there exists an open set of initial data such that the corresponding solution exists in a backward light-cone and approaches the ODE blowup profile. 相似文献
55.
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
56.
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
57.
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
58.
59.
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
60.
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