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971.
972.
S. H. Saker 《Acta Mathematica Hungarica》2003,100(1-2):37-62
We present new oscillation criteria for the second order nonlinear neutral delay differential equation [y(t)-py(t-τ)]'+ q(t)y
λ
(g(t)) sgn y(g(t)) = 0, t ≧ t
0. Our results solve an open problem posed by James S.W . Wong [24]. The relevance of our results becomes clear due to a carefully
selected example.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
973.
M.K. Samal P. Seshu S. Parashar U. von Wagner P. Hagedorn B.K. Dutta H.S. Kushwaha 《Finite Elements in Analysis and Design》2005,41(15):1464-1480
It has been experimentally observed that piezoceramic materials exhibit different types of nonlinearities under different combinations of electric and mechanical fields. When excited near resonance in the presence of weak e to a Duffinor such as jump phenomena and presence of superharmonics in the response spectra. There has not been much work in the litrature to model these types of nonlinearities. Some authors have developed one-dimensional models for the above phenomenon and derived closed-form solutions for the displacement response of piezo-actuators. However, the generalized three-dimensional (3-D) formulation of electric enthalpy, the variational formulation and the FEM implementation have not yet been addressed, which are the focus of this paper. In this work, these nonlinearities have been modelled in a 3-D piezoelectric continuum using higher order quadratic and cubic terms in the generalized electric enthalpy density function. The coupled nonlinear finite element equations have been derived using variational formulation. A special linearization technique for assembling the nonlinear matrices and solution of the resulting nonlinear equations has been developed. The method has been used for simulating the nonlinear frequency response of a lead zirconate titanate plate excited near its first in-plane vibration resonance frequency with sinusoidal excitations of different electric field strengths. The results have been compared with those of the experiment. 相似文献
974.
1IntroductionConsiderthenonlinearhomogeneousdifferenceequationfwhereashi>0,I--1,''5m,qandrarequotientsofpositiveoddintegers,p20,r=p q,a13'',amarepositiveintegerswithal"<''相似文献
975.
中立型时滞差分方程解的渐近性 总被引:3,自引:0,他引:3
给出了中立型时滞差分方程△(xn+pxn-k)+qnf(xn-m)=0一切非振动解趋于零(n→∞)的充分条件,证明了方程(E)一切解振动的两个新的定理。 相似文献
976.
977.
978.
In this paper we consider generalized convexity and concavity properties of the optimal value functionf
* for the general parametric optimization problemP(ε) of the form min
x
f(x, ε) s.t.x∈R(ε). Many results on convexity and concavity characterizations off
* were presented by the authors in a previous paper. Such properties off
* and the solution set mapS
* form an important part of the theoretical basis for sensitivity, stability and parametric analysis in mathematical optimization.
We give sufficient conditions for several types of generalized convexity and concavity off
*, in terms of respective generalized convexity and concavity assumptions onf and convexity and concavity assumptions on the feasible region point-to-set mapR. Specializations of these results to the parametric inequality-equality constrained nonlinear programming problem are provided.
Research supported by Grant ECS-8619859, National Science Foundation and Contract N00014-86-K-0052, Office of Naval Research. 相似文献
979.
980.
G. S. Whiston 《Nonlinear dynamics》1991,2(5):335-351
Elementary applications of singularity theory to dynamical systems are outlined. The main idea is to consider the geometry of the wrinkled surface generated by the time development of a one variable solution as a function of initial conditions or system parameters. Applications of singularity theory to vibro-impacting systems are discussed in some detail and further applications to dynamics are briefly reviewed. 相似文献