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101.
Sang Ro Park 《Mathematische Nachrichten》1999,198(1):169-178
In this paper the non-existence of global solutions of two fourth-order hyperbolic equations with dynamic boundary conditions is considered. Here we prove stronger results than that of M. Kirane, S. Kouachi and N. Tatar by a different method. 相似文献
102.
Stefan Langer 《国际流体数值方法杂志》2012,69(2):332-352
We derive and investigate point implicit Runge–Kutta methods to significantly improve the convergence rate to approximate steady‐state solutions of inviscid flows. It turns out that the point implicit Runge–Kutta can be interpreted as a preconditioned explicit Runge–Kutta method, where the preconditioner arises naturally as local derivative of the residual function. Moreover, many preconditioners suggested in the literature so far are identified as special case of our general ansatz. Conditions will be formulated such that explicit Runge–Kutta methods with local time stepping are equivalent to point implicit methods. In numerical examples, we will demonstrate the improved convergence rates. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
103.
We present a detailed account of the technical aspects of stochastic quantum molecular dynamics, an approach introduced recently by the authors [H. Appel, M. Di Ventra, Phys. Rev. B 80 (2009) 212303] to describe coupled electron-ion dynamics in open quantum systems. As example applications of the method we consider both finite systems with and without ionic motion, as well as describe its applicability to extended systems in the limit of classical ions. The latter formulation allows the study of important phenomena such as decoherence and energy relaxation in bulk systems and surfaces in the presence of time-dependent fields. 相似文献
104.
We study a system of two first-order differential equations arising in averaging nonlinear systems over fast single-frequency
oscillations. We consider the situation where the original system contains weak dissipative terms. We construct the asymptotic
form of a two-parameter solution with an unbounded increasing amplitude. This result gives a key for understanding autoresonance
in weak dissipative systems as a phenomenon of significant increase in the forced nonlinear oscillation initiated by a small
external pumping.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 160, No. 1, pp. 102–111, July, 2009. 相似文献
105.
A modification of the Roe scheme called L2Roe for low dissipation low Mach Roe is presented. It reduces the dissipation of kinetic energy at the highest resolved wave numbers in a low Mach number test case of decaying isotropic turbulence. This is achieved by scaling the jumps in all discrete velocity components within the numerical flux function. An asymptotic analysis is used to show the correct pressure scaling at low Mach numbers and to identify the reduced numerical dissipation in that regime. Furthermore, the analysis allows a comparison with two other schemes that employ different scaling of discrete velocity jumps, namely, LMRoe and a method of Thornber et al. To this end, we present for the first time an asymptotic analysis of the last method. Numerical tests on cases ranging from low Mach number (M∞=0.001) to hypersonic (M∞=5) viscous flows are used to illustrate the differences between the methods and to show the correct behavior of L2Roe. No conflict is observed between the reduced numerical dissipation and the accuracy or stability of the scheme in any of the investigated test cases. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
106.
Chromatographic determination,decline dynamic and risk assessment of sulfoxaflor in Asian pear and oriental melon 下载免费PDF全文
《Biomedical chromatography : BMC》2018,32(3)
The dissipation pattern of sulfoxaflor in Asian pear cultivated in an open field conditions and in oriental melon grown under plastic house conditions was each studied in two different locations. Residues in field‐treated samples were determined using liquid chromatography coupled with an ultraviolet detector and confirmed by liquid chromatography–tandem mass spectrometry. A calibration curve for sulfoxaflor was linear over the concentration range 0.1–5.0 mg/L, with a coefficient of determination of 0.9999. The limits of detection and quantification (LOQ) were 0.007 and 0.02 mg/kg, respectively. Recoveries at three fortification levels (LOQ, 10 × LOQ and maximum residue limit) ranged from 70.5 to 86.2%, with a relative standard deviation ≤5.8%. The dissipation half‐lives were 10.8 and 7.9 days in pear and 5.4 and 5.9 days in oriental melon, at sites 1 and 2, respectively. Based on a pre‐harvest residue limit curve, it was predicted that, if the residues at 10 days before harvest in Asian pear are <0.54/0.61 mg/kg and those in oriental melon are <1.43/1.26 mg/kg, then the residue level will be below the maximum residue limit at harvest. Risk assessment at zero days showed a percentage acceptable daily intake of 10.80% in Asian pear and 1.77 and 1.55% in oriental melon, for sites 1 and 2, respectively. These values indicate that the fruits are safe for consumption. 相似文献
107.
108.
A modification of the material law associated with the well‐known Biot system as suggested by Murad and Cushman (Int. J. Eng. Sci. 1996; 34(3):313–338) and first investigated by Showalter (J. Math. Anal. Appl. 2000; 251(1):310–340) is reconsidered, generalized and analysed in the light of a new approach to a comprehensive class of evolutionary problems. The framework allows a uniform approach to problems involving general anisotropic, inhomogeneous, non‐smooth media thus covering, for example, transmission problems in layered materials. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
109.
A liquid sloshing absorber consists of a container, partially filled with liquid. The absorber is attached to the structure to be controlled, and relies on the structure’s motion to excite the liquid. Consequently, a sloshing wave is produced at the liquid free surface within the absorber, possessing energy dissipative qualities. The behaviour of liquid sloshing absorbers has been well documented, although their use in structural control applications has attracted considerably less attention. 相似文献
110.
爆炸力学数值模拟中本构建模问题的讨论 总被引:19,自引:2,他引:17
就爆炸力学数值模拟中的本构建模问题的有关内容作了讨论,包括:波传播研究与材料的动态特性研究的相互依赖、容变律与畸变律的解耦与耦合、率型本构关系与失效准则、应变率效应与温度效应的等效性、加载本构关系与卸载本构关系以及流变过程与损伤演化过程的耦合等,并展望了今后的有关发展动向。 相似文献