共查询到20条相似文献，搜索用时 31 毫秒
1.
In this paper, first a class of fractional differential equations are obtained by using the fractional variational principles.
We find a fractional Lagrangian L(x(t), where
a
c
D
t
α
x(t)) and 0<α<1, such that the following is the corresponding Euler–Lagrange
At last, exact solutions for some Euler–Lagrange equations are presented. In particular, we consider the following equations
where g(t) and f(t) are suitable functions.
D. Baleanu is on leave of absence from Institute of Space Sciences, P.O. BOX MG-23, 76900 Magurele-Bucharest, Romania. e-mail:
baleanu@venus.nipne.ro. 相似文献
| (1) |
| (2) |
| (3) |
2.
Xinyu He 《Journal of Mathematical Fluid Mechanics》2007,9(3):398-410
Let
be the exterior of the closed unit ball. Consider the self-similar Euler system
Setting α = β = 1/2 gives the limiting case of Leray’s self-similar Navier–Stokes equations. Assuming smoothness and smallness of the boundary
data on ∂Ω, we prove that this system has a unique solution
, vanishing at infinity, precisely
The self-similarity transformation is v(x, t) = u(y)/(t* − t)α, y = x/(t* − t)β, where v(x, t) is a solution to the Euler equations. The existence of smooth function u(y) implies that the solution v(x, t) blows up at (x*, t*), x* = 0, t* < + ∞. This isolated singularity has bounded energy with unbounded L
2 − norm of curl v. 相似文献
3.
Hans-Otto Walther 《Journal of Dynamics and Differential Equations》2009,21(1):195-232
Systems of the form
generalize differential equations with delays r(t) < 0 which are given implicitly by the history x
t
of the state. We show that the associated initial value problem generates a semiflow with differentiable solution operators
on a Banach manifold. The theory covers reaction delays, signal transmission delays, threshold delays, and delays depending
on the present state x(t) only. As an application we consider a model for the regulation of the density of white blood cells and study monotonicity
properties of the delayed argument function . There are solutions (r, x) with τ′(t) > 0 and others with τ′(t) < 0. These other solutions correspond to feedback which reverses temporal order; they are short-lived and less abundant.
Transient behaviour with a sign change of τ′ is impossible.
相似文献
4.
In association with multi-inhomogeneity problems, a special class of eigenstrains is discovered to give rise to disturbance
stresses of interesting nature. Some previously unnoticed properties of Eshelby’s tensors prove useful in this accomplishment.
Consider the set of nested similar ellipsoidal domains {Ω1, Ω2,⋯,Ω
N+1}, which are embedded in an infinite isotropic medium. Suppose that
in which and ξ
t
a
p
, p=1,2,3 are the principal half axes of Ω
t
. Suppose, the distribution of eigenstrain, ε
ij
*(x) over the regions Γ
t
=Ω
t+1−Ω
t
, t=1,2,⋯,N can be expressed as
where x
k
x
l
⋯x
m
is of order n, and f
ijkl ⋯m
(t) represents 3N(n+2)(n+1) different piecewise continuous functions whose arguments are ∑
p=1
3
x
p
2 /a
p
2. The nature of the disturbance stresses due to various classes of the piecewise nonuniform distribution of eigenstrains,
obtained via superpositions of Eq. (‡) is predicted and an infinite number of impotent eigenstrains are introduced. The present theory not only provides a general
framework for handling a broad range of nonuniform distribution of eigenstrains exactly, but also has great implications in
employing the equivalent inclusion method (EIM) to study the behavior of composites with functionally graded reinforcements.
The paper is dedicated to professor Toshio Mura. 相似文献
| (‡) |
5.
K. Pileckas 《Journal of Mathematical Fluid Mechanics》2006,8(4):542-563
The existence and uniqueness of a solution to the nonstationary Navier–Stokes system having a prescribed flux in an infinite
cylinder is proved. We assume that the initial data and the external forces do not depend on x3 and find the solution (u, p) having the following form
where x′ = (x1, x2). Such solution generalize the nonstationary Poiseuille solutions. 相似文献
6.
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
7.
Iterative solution of nonlinear equations with strongly accretive operators in Banach spaces 总被引：1，自引：0，他引：1
周海云 《应用数学和力学(英文版)》1999,20(3):282-289
1IntroductionandPreliminariesLetXbearealBanachspacewithnormIJ'11andadualX'.ThenormalizeddualitymappingJ:X~ZxisdefinedbyJx={x'eX*I(x,x')=11x112=11x if'},where',')denotesthegeneralizeddualitypairing.Itiswell-knownthatifX isstrictlyconvex,Jissingle-valuedandJ(tx)=tjxforallt201xeX.IfX*isuniformlyconvex,thenJisuniformlycontinuousonanyboundedsubsetSofX(of.Browde,fljandBarbuL2]).AnoperatorTwithdomainD(T)andrangeR(T)inXissaidtobeaccretiveifforeveryx,y6D(T),thereexistsajeJ(x--y)suchthat(T… 相似文献
8.
郭艾 《应用数学和力学(英文版)》1999,20(6):683-689
１ＰｒｏｂｌｅｍｓａｎｄＭａｉｎＲｅｓｕｌｔｓＩｎｔｈｉｓｐａｐｅｒ,ｗｅｓｔｕｄｙｔｈｅｎｏｎｌｉｎｅａｒｖｉｂｒａｔｉｏｎｓｏｆｉｎｆｉｎｉｔｅｒｏｄｓｗｉｔｈｖｉｓｃｏｅｌａｓｔｉｃｉｔｙ．Ｔｈｅｃｏｎｓｔｉｔｕｔｉｏｎｌａｗｏｆｔｈｅｒｏｄｓ... 相似文献
9.
李永昆 《应用数学和力学(英文版)》1999,20(5):579-584
ＩｎｔｒｏｄｕｃｔｉｏｎＡｔｐｒｅｓｅｎｔ,ｔｈｅｒｅａｒｅｏｎｌｙａｆｅｗｐａｐｅｒｓ［１～３］ｈａｖｉｎｇｂｅｎｐｕｂｌｉｓｈｅｄｏｎｔｈｅｇｌｏｂａｌｅｘｉｓｔｅｎｃｅｏｆｐｅｒｉｏｄｉｃｓｏｌｕｔｉｏｎｓｆｏｒｎｅｕｔｒａｌｄｅｌａｙｐｏｐｕ... 相似文献
10.
We study the dynamics and regularity of level sets in solutions of the semilinear parabolic equation
where is a ring-shaped domain, a and μ are given positive constants, is the Heaviside maximal monotone graph: if s > 0, if s < 0. Such equations arise in climatology (the so-called Budyko energy balance model), as well as in other contexts such as
combustion. We show that under certain conditions on the initial data the level sets are n-dimensional hypersurfaces in the (x, t)-space and show that the dynamics of Γ
μ
is governed by a differential equation which generalizes the classical Darcy law in filtration theory. This differential
equation expresses the velocity of advancement of the level surface Γ
μ
through spatial derivatives of the solution u. Our approach is based on the introduction of a local set of Lagrangian coordinates: the equation is formally considered
as the mass balance law in the motion of a fluid and the passage to Lagrangian coordinates allows us to watch the trajectory
of each of the fluid particles. 相似文献
11.
It is well-known that a KAM torus can be considered as a graph of smooth viscosity solution. Salamon and Zehnder (Comment
Math Helv 64:84–132, 1989) have proved that there exist invariant tori having prescribed Diophantine frequencies for nearly
integrable and positively definite Lagrangian systems with associated Hamiltonian H, whose Diophantine index is τ. If the invariant torus is represented as in the cotangent bundle , then we can show that for any viscosity solution u (x, P), which satisfies the H-J Eq. (1.1),
when is small enough.
For the more exact form, please see Theorem 2 for details. 相似文献
12.
David N. Cheban 《Journal of Dynamics and Differential Equations》2008,20(3):669-697
In the present article we consider a special class of equations
when the function (E is a strictly convex Banach space) is V-monotone with respect to (w.r.t.) , i.e. there exists a continuous non-negative function , which equals to zero only on the diagonal, so that the numerical function α(t):= V(x
1(t), x
2(t)) is non-increasing w.r.t. , where x
1(t) and x
2(t) are two arbitrary solutions of (1) defined on . The main result of this article states that every V-monotone Levitan almost periodic (almost automorphic, Bohr almost periodic) Eq. (1) with bounded solutions admits at least
one Levitan almost periodic (almost automorphic, Bohr almost periodic) solution. In particulary, we obtain some new criterions
of existence of almost recurrent (Levitan almost periodic, almost automophic, recurrent in the sense of Birkgoff) solutions
of forced vectorial Liénard equations.
相似文献
13.
Ｗｅｈａｖｅｄｉｓｃｕｓｓｅｄｃｏｎｃｅｐｔｏｆｅｑｕａｔｉｏｎｗｉｔｈｎ＿ｔｕｒｎｉｎｇｐｏｉｎｔｓｉｎｍｙｐａｐｅｒ［１］,ｉ．ｅ．,ａｓｅｃｏｎｄｏｒｄｅｒｌｉｎｅａｒｏｒｄｉｎａｒｙｄｉｆｆｅｒｅｎｔｉａｌｅｑｕａｔｉｏｎｄ２ｙｄｘ２＋［λ２ｑ１（ｘ）＋λｑ２（ｘ,λ）］ｙ＝０,ｗｈｅｒｅｑ１（ｘ）＝（ｘ－μ１）（ｘ－μ２）…（ｘ－μｎ）ｆ（ｘ）,ｆ（ｘ）≠０,ａｎｄλｉｓａｌａｒｇｅｐａｒａｍｅｔｅｒ．Ａｌｔｈｒｏｕｇｈｔｈｅｆｉｒｓｔｔｅｒｍｏｆｔｈｅａｓｙｍｐｔｏｔｉｃｅｘｐａｎ… 相似文献
14.
Mei-Yue Jiang 《Journal of Dynamics and Differential Equations》2006,18(4):1043-1067
We consider the periodic solutions of
with f being periodic in t and discontinuous in x. Some results of periodic solutions for continuous nonlinearities are generalized via the critical point theorems for locally Lipschitz functionals. 相似文献
15.
Zhi-Cheng Wang Wan-Tong Li Shigui Ruan 《Journal of Dynamics and Differential Equations》2008,20(3):573-607
In this paper, we study the existence, uniqueness and stability of traveling wave fronts in the following nonlocal reaction–diffusion
equation with delay
Under the monostable assumption, we show that there exists a minimal wave speed c* > 0, such that the equation has no traveling wave front for 0 < c < c* and a traveling wave front for each c ≥ c*. Furthermore, we show that for c > c*, such a traveling wave front is unique up to translation and is globally asymptotically stable. When applied to some population
models, these results cover, complement and/or improve a number of existing ones. In particular, our results show that (i)
if ∂2
f (0, 0) > 0, then the delay can slow the spreading speed of the wave fronts and the nonlocality can increase the spreading
speed; and (ii) if ∂2
f (0, 0) = 0, then the delay and nonlocality do not affect the spreading speed.
相似文献
16.
We study the stationary Dirac equation
where M(x) is a matrix potential describing the external field, and R(x, u) stands for an asymptotically quadratic nonlinearity modeling various types of interaction without any periodicity assumption.
For ħ fixed our discussion includes the Coulomb potential as a special case, and for the semiclassical situation (ħ → 0), we handle the scalar fields. We obtain existence and multiplicity results of stationary solutions via critical point
theory. 相似文献
17.
Georgy M. Kobelkov 《Journal of Mathematical Fluid Mechanics》2007,9(4):588-610
For the system of equations describing the large-scale ocean dynamics, an existence and uniqueness theorem is proved “in the
large”. This system is obtained from the 3D Navier–Stokes equations by changing the equation for the vertical velocity component
u
3 under the assumption of smallness of a domain in z-direction, and a nonlinear equation for the density function ρ is added. More precisely, it is proved that for an arbitrary
time interval [0, T], any viscosity coefficients and any initial conditions
a weak solution exists and is unique and and the norms are continuous in t.
The work was carried out under partial support of Russian Foundation for Basic Research (project 05-01-00864). 相似文献
18.
Let X be a uniformly smooth real Banach space. Let T:X → X be continuos and strongly accretive operator. For a given f ε X,
define S: X → X by Sx =f−Tx+x, for all x ε X. Let {an}
n=0
∞
, {βn}
n=0
∞
be two real sequences in (0, 1) satisfying:
;
Assume that {un}
n=0
∞
and {υn}
n=0
∞
are two sequences in X satisfying ‖un‖ = 0(αn) and ‖υn‖ → 0 as n → ∞. For arbitrary x0 ε X, the iteration sequence {xn} is defined by
Moreover, suppose that {Sxn} and {Syn} are bounded, then {xn} converges strongly to the unique fixed point of S. 相似文献
| ((i)) |
| ((ii)) |
| (1) |
19.
S. H. Saker 《Nonlinear Oscillations》2011,13(3):407-428
Our aim is to establish some sufficient conditions for the oscillation of the second-order quasilinear neutral functional
dynamic equation
|
( p(t)( [ y(t) + r(t)y( t(t) ) ]D )g )D + f( t,y( d(t) ) = 0, t ? [ t0,￥ )\mathbbT, {\left( {p(t){{\left( {{{\left[ {y(t) + r(t)y\left( {\tau (t)} \right)} \right]}^\Delta }} \right)}^\gamma }} \right)^\Delta } + f\left( {t,y\left( {\delta (t)} \right)} \right. = 0,\quad t \in {\left[ {{t_0},\infty } \right)_\mathbb{T}}, 相似文献
20.
Philippe G. Ciarlet Liliana Gratie Cristinel Mardare 《Archive for Rational Mechanics and Analysis》2008,188(3):457-473
The fundamental theorem of surface theory classically asserts that, if a field of positive-definite symmetric matrices (a
αβ
) of order two and a field of symmetric matrices (b
αβ
) of order two together satisfy the Gauss and Codazzi-Mainardi equations in a simply connected open subset ω of , then there exists an immersion such that these fields are the first and second fundamental forms of the surface , and this surface is unique up to proper isometries in . The main purpose of this paper is to identify new compatibility conditions, expressed again in terms of the functions a
αβ
and b
αβ
, that likewise lead to a similar existence and uniqueness theorem. These conditions take the form of the matrix equation
|