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1.
In this paper we are interested in the large time behavior of the nonlinear diffusionequationu_1=(φ(u))_xx φ(u), x∈R,t∈R~ =(0, ∞))We consider functionsφ(u)andφ(u)which allow the equation to possess travelingwave solutions.We first present an existence and uniqueness as well as some comparisonprinciple result of generalized solutions to the Cauchy problem.Then we give forφ(u)=u(1-u)(u-a)some threshold results,from which we can see that u=a is stable,while u=0 or u=1 is unstable under some assumptions,etc.  相似文献   

2.
This paper deals with connected branches of nonstationary periodic trajectories of Hamilton equations
emanating from the degenerate stationary point for H being the generalized Hénon-Heiles (HH) Hamiltonian:
or the generalized Yang-Mills (YM) Hamiltonian:
The existence of such branches has been proved. Minimal periods of searched trajectories near x0 have been described.  相似文献   

3.
Uptonow ,thequalitativebehaviorofthesecond_ordernonlineardifferentialequationsandtheirapplicationshavebeendiscussedextensivelyinliterature.WerefertotheRefs .[1 -8] .Conversely ,thediscussionforthequalitativebehaviorofthedelaysystemisless .Inthispaper,westudyt…  相似文献   

4.
By using comparison theorem and constructing suitable Lyapunov functional, we study the following periodic Lotka–Volterra model with M-predators and N-preys by pure-delay type
A set of easily verifiable sufficient conditions are obtained for the existence and global attractivity of a unique positive almost periodic solution of the above model, which improve and generalize some known results.  相似文献   

5.
LetP(t) denote the density of mature cells in blood circulation. Mackey and Glass (1977) have proposed the following equations:
  相似文献   

6.
IntroductionAtpresent,thereareonlyafewpapers[1~3]havingbenpublishedontheglobalexistenceofperiodicsolutionsforneutraldelaypopu...  相似文献   

7.
IntroductionIntherecentyears,withalotofapplicationsofneuralnetworkmodels,manyauthors[1~3]areinterestedintheresearchofthestructureandperformanceforthesenetworks.BecauseHopfieldneuralnetworkwellsimulatetheecologicalsystem,manystudiesareconcentratedonth…  相似文献   

8.
IntroductionOwingtotheextensiveapplicationofneutralequations,moreandmorestudieshavebenmadeonthebehaviorofthesolutions[1,2].Fo...  相似文献   

9.
A criterion to predict bifurcation of homoclinic orbits instrongly nonlinear self-excited one-degree-of-freedom oscillator
is presented. TheLindstedt–Poincaré perturbation method is combined formally withthe Jacobian elliptic functions to determine an approximation of thelimit cycles near homoclinicity. We then apply a criterion forpredicting homoclinic orbits, based on the collision of the bifurcatinglimit cycle with the saddle equilibrium. In particular we show that thiscriterion leads to the same results, formally and to leading order, asthe standard Melnikov technique. Explicit applications of this criterionto quadratic or cubic nonlinearities f(x) are included.  相似文献   

10.
We investigate the dynamics of the semiflow φ induced on H01(Ω) by the Cauchy problem of the semilinear parabolic equation
on Ω. Here is a bounded smooth domain, and has subcritical growth in u and satisfies . In particular we are interested in the case when f is definite superlinear in u. The set
of attraction of 0 contains a decreasing family of invariant sets
distinguished by the rate of convergence . We prove that the Wk’s are global submanifolds of , and we find equilibria in the boundaries . We also obtain results on nodal and comparison properties of these equilibria. In addition the paper contains a detailed exposition of the semigroup approach for semilinear equations, improving earlier results on stable manifolds and asymptotic behavior near an equilibrium.Supported by DFG Grant BA 1009/15-1.  相似文献   

11.
This paper examines the asymptotic behavior of measure valued solutions to the initial value problem for the nonlinear heat conduction equation
  相似文献   

12.
The article deals with positive solutions of the Dirichlet problem for
where f(s)>0 for s>0 and f(0)=0. The asymptotic behavior of solutions is discussed for a rather large class of g. For g regular near zero, stability properties of equilibria are investigated.  相似文献   

13.
Measurements on seven rigid PVC compounds were carried out with a slit rheometer working in combination with an injection moulding machine. Plastication of the compounds occurred in the screw of the plastication unit, which also forced the melt through the die with a controlled forward velocity. The rectangular slit had a length of 90 mm and a widthB of 20 mm. The heightH could be varied between 0.8 and 3.3 mm. Pressures and temperatures were recorded at several positions in and before the die. Measurements were carried out at shear rates from 10 to 2000 s–1.When the reduced volume output was plotted against the wall shear stress W , only four compounds showed master curves independent ofH, which is indicative of wall adhesion. In the other cases this plot did not produce such a master curve, but the plot of the mean velocity against W was independent ofH (slip curve). This indicated that slip flow prevailed with a slip velocityv G When, in the case of wall slip, the smooth inner surfaces of the die were replaced by surfaces with grooves perpendicular to the direction of flow, slip flow was prevented and the flow curves were shifted to much higher values of Wc Above a critical value of the wall shear stress ( Wc ) at which slip flow began, the output became nearly independent of W . From the measurements made below Wc a vs. relation for the shear flow could be derived, which was used to calculate the superimposed shear flow . Exact values of the slip velocity were then given by . Wall slip only occurred for compounds with a high shear viscosity, which corresponds to a high molecular weight (K-value).Dedicated to Professor H. Janeschitz-Kriegl on the occasion of his 60th birthday.  相似文献   

14.
IntroductionConsiderthenonlinearautonomousdelaydifferentialequationx′(t) ∑mi=1pifi(x(t-τi) ) =0 (1 )andthelinearequationx′(t) ∑mi=1pix(t-τi) =0 ,(2 )where ,pi ∈ (0 ,∞ ) ,τi ∈ [0 ,∞ )andfi ∈C(R ,R)fori =1 ,… ,m .InRef.[1 ] ,thelinearizedoscillationsofEq .(1 )wasstudiedanditwasprovedthatift…  相似文献   

15.
Let E be a Banach space. We prove the instability of the trivial solution of the differential equation
where f: [0, +∞) × E → ℝ is a continuous mapping for which
__________ Translated from Neliniini Kolyvannya, Vol. 8, No. 3, pp. 404–414, July–September, 2005.  相似文献   

16.
We consider the system of difference equations
where > 0 and T N 0. Our aim is to determine the values of for which the above system has a constant-sign solution. In addition, explicit intervals for are presented. The generality of the results obtained is illustrated through applications to several well-known boundary-value problems. We also extend the above problem to that on {0, 1, ...}:
Finally, both systems above are extended to the general case where is replaced by i .  相似文献   

17.
Foschi  S.  Mingari Scarpello  G.  Ritelli  D. 《Meccanica》2004,39(4):357-368
In 1985 Franz Rothe [J. Reine Angew Math. 355 (1985) 129–138] found, by means of the thermodynamical equilibrium theory, an asymptotic estimate of the period of solutions of ordinary differential equations originated by predator–prey Volterra–Lotka model. We extend some of the Rothe's ideas to more general systems:
and succeed in calculating the period's asymptotic analytic expression as a function of the energy level. We finally check our result re-obtaining classical period's estimation of some popular Hamiltonian systems. We apply our technique also to a non-linear Hamiltonian system whose period is not available in the literature.  相似文献   

18.
Consideringthehigherdimensionalperiodicsystemswithdelayoftheformx′(t)=A(t,x(t))x(t)+f(t,x(t-τ)),(1)x′(t)=gradG(x(t))+f(t,x(t-...  相似文献   

19.
The paper gives a solution of the random differential equation with random coefficient, that is , where K (t) is a random process and is a damp coefficient, it is a little parameter.  相似文献   

20.
We establish the saddle-point property of the system of functional differential equations (t) = Ax(t) + Bx((t)) + C ((t)) + f (x(t), x((t))), (0) = 0.Translated from Neliniini Kolyvannya, Vol. 7, No. 3, pp. 302–310, July–September, 2004.  相似文献   

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