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91.
一类脉冲中立型时滞抛物方程组的振动性 总被引:7,自引:0,他引:7
研究一类脉冲中立型时滞抛物方程组解的振动性,得到了该类方程组在两类不同边界条件下所有解振动的若干充分条件. 相似文献
92.
Differential algebraic equations with after-effect 总被引:4,自引:0,他引:4
C. T. H. Baker C. A. H. Paul H. Tian 《Journal of Computational and Applied Mathematics》2002,140(1-2):63-80
In this paper, we are concerned with the solution of delay differential algebraic equations. These are differential algebraic equations with after-effect, or constrained delay differential equations. The general semi-explicit form of the problem consists of a set of delay differential equations combined with a set of constraints that may involve retarded arguments. Even simply stated problems of this type can give rise to difficult analytical and numerical problems. The more tractable examples can be shown to be equivalent to systems of delay or neutral delay differential equations. Our purpose is to highlight some of the complexities and obstacles that can arise when solving these problems, and to indicate problems that require further research. 相似文献
93.
Veronica Felli Susanna Terracini 《Calculus of Variations and Partial Differential Equations》2006,27(1):25-58
This paper deals with a class of nonlinear elliptic equations involving a critical power-nonlinearity as well as a potential featuring multiple inverse square singularities. When the poles form a symmetric structure, it is natural we wonder how the symmetry affects such mutual interaction. The present paper means to study this aspect from the point of view of the existence of solutions inheriting the same symmetry properties as the set of singularities.
Mathematics Subject Classification (2000) 35J60, 35J20, 35B33 相似文献
94.
超声波波型转换与表面波的检测 总被引:1,自引:0,他引:1
分析了超声波纵波、横波、表面波3种波型的产生条件和声速关系,检测了超声波在固体表面的波型转换,并测量了声表面波的速度,讨论了声表面波在超声延迟线方面的应用. 相似文献
95.
Although quantum field theory allows the local energy density negative, it also places severe restrictions on the negative energy. One of the restrictions is the quantum energy inequality (QEI), in which the energy density is averaged over time, or space, or over space and time. By now temporal QEIs have been established for various quantum fields, but less work has been done for the spacetime quantum energy inequality. In this paper we deal with the free Rarita-Schwinger field and present a quantum inequality bound on the energy density averaged over space and time.Comparison with the QEI for the Rarita-Schwinger field shows that the lower bound is the same with the QEI. At the same time, we find the quantum inequality for the Rarita-Schwinger field is weaker than those for the scalar and Dirac fields. This fact gives further support to the conjecture that the more freedom the field has, the more easily the field displays negative energy density and the weaker the quantum inequality becomes. 相似文献
96.
The present paper deals with the long-time behavior of a class of nonautonomous retarded semilinear parabolic differential equations. When the time delays are small enough and the spectral gap conditions hold, the inertial manifolds of the nonautonomous retard parabolic equations are constructed by using the Lyapunov-Perron method. 相似文献
97.
98.
Mark L. Lewis 《Algebras and Representation Theory》2002,5(3):277-304
Let G be a solvable group with five character degrees. Suppose that there is some prime p so that G/O
p
(G) is not Abelian. Also, assume that cd(G) contains a degree that is not divisible by p. Under these hypotheses, we show that the derived length of G is at most 4. 相似文献
99.
The asymptotic null distribution of the likelihood ratio test for two cases of ordered hypotheses in a particular genetic model is considered. A simple iterative process is proposed in order to get the restricted estimates. It is shown that both tests have asymptotically a chi-bar squared distribution and the same size. A simulation study is also conducted in order to compare the usual unrestricted test with the corresponding one of ordered hypotheses. Finally, the results are extended to some special cases. 相似文献