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41.
Qing An WU Zhen Yuan XU Mei ZHENG Dan Qian XU Jun XU Yin Chu SHENCollege of Chemical Engineering Materials Zhejiang University of Technology Hangzhou 《中国化学快报》2004,(7)
Six new 13-O-acylavermectin Bl aglycones(3-8) were synthesized from avermectin B1 aglycone and their bioactivities were evaluated against Spodoptera exigua, Spodoptera eridania, Tetranychus urticae and Aphis fabae. 相似文献
42.
Fabio A. C. C. Chalub Peter A. Markowich Benoît Perthame Christian Schmeiser 《Monatshefte für Mathematik》2004,142(1-2):123-141
Kinetic models for chemotaxis, nonlinearly coupled to a Poisson equation for the chemo-attractant density, are considered. Under suitable assumptions on the turning kernel (including models introduced by Othmer, Dunbar and Alt), convergence in the macroscopic limit to a drift-diffusion model is proven. The drift-diffusion models derived in this way include the classical Keller-Segel model. Furthermore, sufficient conditions for kinetic models are given such that finite-time-blow-up does not occur. Examples are given satisfying these conditions, whereas the macroscopic limit problem is known to exhibit finite-time-blow-up. The main analytical tools are entropy techniques for the macroscopic limit as well as results from potential theory for the control of the chemo-attractant density.Present address: Centro de Matemática e Aplicações Fundamentais, Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003, Lisboa, Portugal 相似文献
43.
Zhaoyang Yin 《Monatshefte für Mathematik》2004,141(4):337-344
We prove under quite general assumptions the existence of a bounded positive solution to the semilinear Schrödinger equation in a two-dimensional exterior domain. 相似文献
44.
We prove the existence of solutions to nonlinear free boundary problem with singularities at given points. 相似文献
45.
C. Sparber J. A. Carrillo J. Dolbeault P. A. Markowich 《Monatshefte für Mathematik》2004,141(3):237-257
We analyze the long-time behavior of transport equations for a class of dissipative quantum systems with Fokker-planck type diffusion operator, subject to confining potentials of harmonic oscillator type. We establish the existence and uniqueness of a non-equilibrium steady state for the corresponding dynamics. Further, using a (classical) convex Sobolev inequality, we prove an optimal exponential rate of decay towards this state and additionally give precise dispersion estimates in those cases, where no stationary state exists. 相似文献
46.
On a Definitizable Analog of the Trigonometric Moment Problem Generating an Indefinite Toeplitz Form
We prove the existence of an integro-polynomial representation for a sequence of numbers such that there exists a difference operator mapping this sequence to a sequence that generates the solvable trigonometric moment problem. A similar result related to the power moment problem was given in [12]. 相似文献
47.
Walter Benz 《Monatshefte für Mathematik》2004,141(1):1-10
The lines of euclidean and hyperbolic geometries are characterized as metric lines in the sense of Blumenthal–Menger, and the lines of spherical and elliptic geometry as periodic ones. In euclidean geometries there do not exist periodic lines. 相似文献
48.
Victor Bondarenko 《Bulletin des Sciences Mathématiques》2003,127(3):191-206
In present paper the parabolic equation solution is built. The construction is reduced to iterative procedure. And convergence of the latter is proven. 相似文献
49.
We investigate several versions of a cardinal characteristic defined by Frankiewicz. Vojtáš showed , and Blass showed . We show that all the versions coincide and that is greater than or equal to the splitting number. We prove the consistency of and of .
Received: 2 October 1996 / Revised version: 22 May 1997 相似文献
50.
Modifying complex plane rotations, we derive a new Jacobi-type algorithm for the Hermitian eigendecomposition, which uses only real arithmetic. When the fast-scaled rotations are incorporated, the new algorithm brings a substantial reduction in computational costs. The new method has the same convergence properties and parallelism as the symmetric Jacobi algorithm. Computational test results show that it produces accurate eigenvalues and eigenvectors and achieves great reduction in computational time.The work of this author was supported in part by the National Science Foundation grant CCR-8813493 and by the University of Minnesota Army High Performance Computing Research Center contract DAAL 03-89-C-0038.The work of this author was supported in part by the University of Minnesota Army High Performance Computing Research Center contract DAAL 03-89-C-0038. 相似文献