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排序方式: 共有370条查询结果,搜索用时 140 毫秒
81.
Caiming Lei 《Applied mathematics and computation》2009,215(8):2855-2857
In this remark, we shall show that the Lemma 1 and parts of the proof of Theorem 1 in the paper “Oscillation criteria for second-order linear difference equations” (Applied Mathematics and Computation 145 (2003) 591-601) are incorrect. 相似文献
82.
The ion-exchange electrochromatography with an oscillatory electric field perpendicular to the mobile-phase flow driven by pressure (pIEEC) was used to separate hen egg-white (HEW) proteins. The results were compared with those of normal ion-exchange chromatography (IEC). The column was designed as three-compartment rectangular column of 2-mL with dimensions (length x width x depth) of 40 x 10 x 5 mm(3) and the electric field was applied across the direction of column width. Q Sepharose FF was packed into the central compartment as the chromatographic bed. It was confirmed that the dynamic binding capacity (DBC) of different proteins (ovotransferrin and ovalbumin) in the HEW solution increased 2.3 times when an oscillatory electric current of 30 mA at 1/20 Hz was applied in the transverse column direction. Then, the HEW proteins were separated by the pIEEC at loading amounts 2.3-fold higher than those by the IEC. When the feedstock of about one-third of the DBC was applied to the columns (i.e., 7 mL for the pIEEC and 3 mL for the IEC), similar separation efficiencies of the two chromatographic modes were achieved. Both the recovery yield and purity reached 73% to over 90%. The results indicate that the pIEEC is promising for high-capacity purification of proteins. 相似文献
83.
The motion around the center of mass of a rigid unmanned aircraft, whose flight control system fails, in an “Aero Data Model In a Research Environment” is described, by a set of nine nonlinear ordinary differential equations. The longitudinal flight with constant forward velocity is described by a subset of three nonlinear differential equations, obtained from the general system. In this paper, the existence of oscillatory solutions of this system of three differential equations is proved by means of coincidence degree theory and Mawhin's continuation theorem. 相似文献
84.
Björn Engquist 《Journal of Computational and Applied Mathematics》2010,234(6):1851-1859
This paper presents a new directional multilevel algorithm for solving N-body or N-point problems with highly oscillatory kernels. We address the problem by first proving that the interaction between a ball of radius r and a well-separated region has an approximate low rank representation, as long as the well-separated region belongs to a cone with a spanning angle of O(1/r) and is at a distance which is at least O(r2) away from the ball. Based on this representation, our algorithm organizes the high frequency computation using a multidirectional and multiscale strategy. Our algorithm is proved to have an optimal O(NlogN) computational complexity for any given accuracy when the points are sampled from a two-dimensional surface. 相似文献
85.
A sixth order diagonally implicit symmetric and symplectic Runge-Kutta method for solving Hamiltonian systems
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The paper is concerned with construction of symmetric and symplectic Runge-Kutta methods for Hamiltonian systems. Based on the symplectic and symmetrical properties, a sixth-order diagonally implicit symmetric and symplectic Runge-Kutta method with seven stages is presented, the proposed method proved to be P-stable. Numerical experiments with some Hamiltonian oscillatory problems are presented to show the proposed method is as competitive as the existing Runge-Kutta methods in scientic literature. 相似文献
86.
Estimates of oscillatory integrals with stationary phase and singular amplitude: Applications to propagation features for dispersive equations
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《Mathematische Nachrichten》2018,291(5-6):793-826
In this paper, we study time‐asymptotic propagation phenomena for a class of dispersive equations on the line by exploiting precise estimates of oscillatory integrals. We propose first an extension of the van der Corput Lemma to the case of phases which may have a stationary point of real order and amplitudes allowed to have an integrable singular point. The resulting estimates provide optimal decay rates which show explicitly the influence of these two particular points. Then we apply these abstract results to solution formulas of a class of dispersive equations on the line defined by Fourier multipliers. Under the hypothesis that the Fourier transform of the initial data has a compact support or an integrable singular point, we derive uniform estimates of the solutions in space‐time cones, describing their motions when the time tends to infinity. The method permits also to show that symbols having a restricted growth at infinity may influence the dispersion of the solutions: we prove the existence of a cone, depending only on the symbol, in which the solution is time‐asymptotically localized. This corresponds to an asymptotic version of the notion of causality for initial data without compact support. 相似文献
87.
Hongchao Kang 《Applied mathematics and computation》2010,217(8):3890-3897
In this paper we explore the evaluation of highly oscillatory integrals containing an algebraic singularity based on the change of variable t = x−r, where r is a positive real number, and the analytical continuation. Robust numerical results demonstrate the accuracy and effectiveness of the proposed approach. 相似文献
88.
The mathematical analogy between properties of simple and complex models of non-linear reactions was used to determine reaction steps in the complex model, necessary to generate instability region and appropriate type of bifurcations on the border between stable and unstable non-equilibrium stationary state. The autocatalator was recognized as the simple prototype two-variable non-linear model practical for examination of the complex four-variable non-linear neuroendocrine system known as the Hypothalamic-Pituitary-Adrenal (HPA) axis. In both cases, we derived the instability criteria by stoichiometric network analysis (SNA), determine conditions under which dynamic transitions, i.e. bifurcations occur, and identify the type of bifurcation. The supercritical Andronov–Hopf bifurcation was found in both cases whereas saddle-node bifurcation was detected only in the model for HPA axis.Thus, by stoichiometric network analysis, the mathematical analogy is found between two different models with same autocatalytic steps, that is, between two models with easily recognizable qualitative analogy. 相似文献
89.
Guangying Lv 《Journal of Mathematical Analysis and Applications》2010,370(1):82-100
In this paper, we study the existence, uniqueness and profiles of traveling waves to some integral-differential equations arising from nonlinear nonlocal neuronal networks with oscillatory kernels. Our approach is fundamental ideas in differential equation and function analysis. 相似文献
90.
In this paper, we are concerned with the global attractivity of the positive equilibrium of the following delay “food-limited” model with exponential impulses: