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1.
Intervals of the parameters λ and μ are determined for which there exist positive solutions to the system of dynamic equations $$ \begin{array}{lll} && (-1)^nu^{\Delta^{2n}}(t)+\lambda p(t)f(v(\sigma(t)))=0,\quad t\in[a, b], \\ &&(-1)^n v^{\Delta^{2n}}(t)+\mu q(t)g(u(\sigma(t)))=0, \quad t\in[a, b], \end{array} $$ satisfying the Sturm–Liouville boundary conditions $$ \begin{array}{lll} &&\alpha_{i+1} u^{\Delta^{2i}}(a)-\beta_{i+1} u^{\Delta^{2i+1}}(a)=0,\;\gamma_{i+1} u^{\Delta^{2i}}(\sigma(b))+\delta_{i+1} u^{\Delta^{2i+1}}(\sigma(b))=0,\\ &&\alpha_{i+1} v^{\Delta^{2i}}(a)-\beta_{i+1} v^{\Delta^{2i+1}}(a)=0,\; \gamma_{i+1} v^{\Delta^{2i}}(\sigma(b))+\delta_{i+1} v^{\Delta^{2i+1}}(\sigma(b))=0, \end{array} $$ for 0?≤?i?≤?n???1. To this end we apply a Guo–Krasnosel’skii fixed point theorem.  相似文献   

2.
In this paper, we are concerned with the existence criteria for positive solutions of the following nonlinear arbitrary order fractional differential equations with deviating argument
$\left \{{l@{\quad}l}D_{0^+}^{\alpha}u(t)+h(t)f(u(\theta(t)))=0, & t\in ( 0,1 ),\ n-1<\alpha\leq n,\\[3pt]u^{(i)}(0)=0, & i=0,1,2,\ldots,n-2,\\[3pt][D_{0^+}^{\beta} u(t)]_{t=1}=0, & 1\leq\beta\leq n-2, \right .$\left \{\begin{array}{l@{\quad}l}D_{0^+}^{\alpha}u(t)+h(t)f(u(\theta(t)))=0, & t\in ( 0,1 ),\ n-1<\alpha\leq n,\\[3pt]u^{(i)}(0)=0, & i=0,1,2,\ldots,n-2,\\[3pt][D_{0^+}^{\beta} u(t)]_{t=1}=0, & 1\leq\beta\leq n-2,\end{array} \right .  相似文献   

3.
This paper deals with the existence of weak solutions to a class of degenerate and singular elliptic systems in ℝ N , N 2 of the form
$\left\{{l@{\quad}l}-\mathop{\mathrm{div}}(h_{1}(x)\nabla u)+a(x)u=f(x,u,v)&\mbox{in}\mathbb{R}^{N},\\-\mathop{\mathrm{div}}(h_{2}(x)\nabla v)+b(x)v=g(x,u,v)&\mbox{in}\mathbb{R}^{N},\right.$\left\{\begin{array}{l@{\quad}l}-\mathop{\mathrm{div}}(h_{1}(x)\nabla u)+a(x)u=f(x,u,v)&\mbox{in}\mathbb{R}^{N},\\-\mathop{\mathrm{div}}(h_{2}(x)\nabla v)+b(x)v=g(x,u,v)&\mbox{in}\mathbb{R}^{N},\end{array}\right.  相似文献   

4.
We study the global in time existence of small classical solutions to the nonlinear Schrödinger equation with quadratic interactions of derivative type in two space dimensions $\left\{\begin{array}{l@{\quad}l}i \partial _{t} u+\frac{1}{2}\Delta u=\mathcal{N}\left( \nabla u,\nabla u\right),&;t >0 ,\;x\in {\bf R}^{2},\\ u\left( 0,x\right) =u_{0} \left( x\right),&;x\in {\bf R}^{2}, \end{array}\right.\quad\quad\quad\quad\quad\quad (0.1)$ where the quadratic nonlinearity has the form ${\mathcal{N}( \nabla u,\nabla v) =\sum_{k,l=1,2}\lambda _{kl} (\partial _{k}u) ( \partial _{l}v) }We study the global in time existence of small classical solutions to the nonlinear Schr?dinger equation with quadratic interactions of derivative type in two space dimensions
$\left\{{l@{\quad}l}i \partial _{t} u+\frac{1}{2}\Delta u=\mathcal{N}\left( \nabla u,\nabla u\right),&t >0 ,\;x\in {\bf R}^{2},\\ u\left( 0,x\right) =u_{0} \left( x\right),&x\in {\bf R}^{2}, \right.\quad\quad\quad\quad\quad\quad (0.1)$\left\{\begin{array}{l@{\quad}l}i \partial _{t} u+\frac{1}{2}\Delta u=\mathcal{N}\left( \nabla u,\nabla u\right),&t >0 ,\;x\in {\bf R}^{2},\\ u\left( 0,x\right) =u_{0} \left( x\right),&x\in {\bf R}^{2}, \end{array}\right.\quad\quad\quad\quad\quad\quad (0.1)  相似文献   

5.
Da-Xue Chen 《Acta Appl Math》2010,109(3):703-719
In this paper, we derive some sufficient conditions for the oscillation and asymptotic behavior of the nth-order nonlinear neutral delay dynamic equations
${rcl}&&\left\{a(t)\Psi(x(t))\left[|(x(t)+p(t)x(\tau(t)))^{\Delta ^{n-1}}|^{\alpha-1}(x(t)+p(t)x(\tau(t)))^{\Delta^{n-1}}\right]^{\gamma}\right\}^{\Delta}\\[12pt]&&{}\quad +\lambda F(t,x(\delta(t)))=0,$\begin{array}{rcl}&&\left\{a(t)\Psi(x(t))\left[|(x(t)+p(t)x(\tau(t)))^{\Delta ^{n-1}}|^{\alpha-1}(x(t)+p(t)x(\tau(t)))^{\Delta^{n-1}}\right]^{\gamma}\right\}^{\Delta}\\[12pt]&&{}\quad +\lambda F(t,x(\delta(t)))=0,\end{array}  相似文献   

6.
In this paper we deal with local estimates for parabolic problems in ${\mathbb{R}^N}$ with absorbing first order terms, whose model is $$\left\{\begin{array}{l@{\quad}l}u_t- \Delta u +u |\nabla u|^q = f(t,x) \quad &{\rm in}\, (0,T) \times \mathbb{R}^N\,,\\u(0,x)= u_0 (x) &{\rm in}\, \mathbb{R}^N \,,\quad\end{array}\right.$$ where ${T >0 , \, N\geq 2,\, 1 < q \leq 2,\, f(t,x)\in L^1\left( 0,T; L^1_{\rm loc} \left(\mathbb{R}^N\right)\right)}$ and ${u_0\in L^1_{\rm loc}\left(\mathbb{R}^{N}\right)}$ .  相似文献   

7.
We consider the following fourth order mean field equation with Navier boundary condition $$\Delta^2 u = \rho \frac{h(x) e^{u}}{\int_\Omega h e^{u}}\,\,{\rm in}\, \Omega,{\quad}u = \Delta u = 0\,\,{\rm on}\,\partial \Omega,\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad(*)$$ where h is a C 2,?? positive function, ?? is a bounded and smooth domain in ${\mathbb{R}^4}$ . We prove that for ${\rho \in (32m\sigma_3, 32(m + 1)\sigma_3)}$ the degree-counting formula for (*) is given by $$d(\rho)=\left\{\begin{array}{ll}\frac{1}{m!} (-\chi (\Omega) +1) \cdot\cdot \cdot (-\chi(\Omega)+m) & {\rm for}\, m >0 ,\\ 1 & {\rm for}\, m=0\end{array}\right.$$ where ??(??) is the Euler characteristic of ??. Similar result is also proved for the corresponding Dirichlet problem $$\Delta^2 u = \rho \frac{h(x) e^{u}}{\int_\Omega h e^{u}}\quad{\rm in}\,\Omega, \quad u = \nabla u = 0 \quad {\rm on}\,\,\partial \Omega.\quad\quad\quad\quad\quad\quad\quad\quad\quad\quad(**)$$   相似文献   

8.
Fujita exponents for evolution problems with nonlocal diffusion   总被引:1,自引:0,他引:1  
We prove the existence of a critical exponent of Fujita type for the nonlocal diffusion problem
$\left\{{l@{\quad}l}u_t(x, t) = J*u(x, t)-u(x, t) + u^p(x, t), & \qquad x \in \mathbb{R}^N,\; t > 0,\\ u(x, 0) = u_0(x), & \qquad x \in\mathbb{R}^N,\right.$\left\{\begin{array}{l@{\quad}l}u_t(x, t) = J*u(x, t)-u(x, t) + u^p(x, t), & \qquad x \in \mathbb{R}^N,\; t > 0,\\ u(x, 0) = u_0(x), & \qquad x \in\mathbb{R}^N,\end{array}\right.  相似文献   

9.
The study of dynamic equations on time scales is an area of mathematics. It has been created in order to unify the study of differential and difference equations. In this paper, we consider the time-scale boundary value problems
where is a time scale. By means of Leggett-Williams fixed point theorem, sufficient conditions are obtained that guarantee the existence of at least three positive solutions to the above boundary value problem. The results obtained are even new for the special cases of difference dynamic equations (when ) and differential dynamic equations (when ), as well as in the general time scale setting. Supported by National Natural Sciences Foundation of China (10671012) and the Doctoral Program Foundation of Education Ministry of China (20050007011).  相似文献   

10.
In this paper, we consider the functional differential equation with impulsive perturbations
$ \left\{ {{*{20}{c}} {{x^{\prime}}(t) = f\left( {t,{x_t}} \right),} \hfill & {t \geq {t_0},\quad t \ne {t_k},\quad x \in {\mathbb{R}^n},} \hfill \\ {\Delta x(t) = {I_k}\left( {t,x\left( {{t^{-} }} \right)} \right),} \hfill & {t = {t_k},\quad k \in {\mathbb{Z}^{+} }.} \hfill \\ } \right. $ \left\{ {\begin{array}{*{20}{c}} {{x^{\prime}}(t) = f\left( {t,{x_t}} \right),} \hfill & {t \geq {t_0},\quad t \ne {t_k},\quad x \in {\mathbb{R}^n},} \hfill \\ {\Delta x(t) = {I_k}\left( {t,x\left( {{t^{-} }} \right)} \right),} \hfill & {t = {t_k},\quad k \in {\mathbb{Z}^{+} }.} \hfill \\ \end{array} } \right.  相似文献   

11.
The aim of this work is to study the existence of solutions of quasilinear elliptic problems of the type
$\left\{{ll}-{\rm div}([a(x) + |u|^q] \nabla u) + b(x)u|u|^{p-1}|\nabla u|^2 = f(x), & {\rm in}\,\Omega;\\ \quad \quad \quad \quad \quad \quad \quad \quad \quad \; u = 0, & \,{\rm on}\,\partial\Omega. \right.$\left\{\begin{array}{ll}-{\rm div}([a(x) + |u|^q] \nabla u) + b(x)u|u|^{p-1}|\nabla u|^2 = f(x), & {\rm in}\,\Omega;\\ \quad \quad \quad \quad \quad \quad \quad \quad \quad \; u = 0, & \,{\rm on}\,\partial\Omega. \end{array}\right.  相似文献   

12.
Consider the linear neutral functional differential equation of the form
$\left\{{l@{\quad }l}\frac{\partial}{\partial t}Fu_t=BFu_t+\Phi u_t, & t\ge 0,\\[3pt]u_0(s)=\varphi(s),& s\in [-r,0],\right.$\left\{\begin{array}{l@{\quad }l}\frac{\partial}{\partial t}Fu_t=BFu_t+\Phi u_t, & t\ge 0,\\[3pt]u_0(s)=\varphi(s),& s\in [-r,0],\end{array}\right.  相似文献   

13.
In this work, we consider the following second-order m-point boundary value problem on time scales $$\left\{\begin{array}{@{}l}(\phi_{p}(u^{\triangle}(t)))^{\nabla}+h(t)f(t,u(t),u^{\triangle }(t))=0,\quad t\in(0,+\infty)_{\mathbb{T}},\\[4pt]\displaystyle u(0)=\sum_{i=1}^{m-2}\alpha_{i}u(\eta_{i}),\qquad u^{\triangle}(+\infty)=\sum_{i=1}^{m-2}\beta_{i}u^{\triangle}(\eta_{i}).\end{array}\right.$$ We establish new criteria for the existence of at least three unbounded positive solutions. Our results are new even for the corresponding differential $({\mathbb{T}}={\mathbb{R}})$ , difference equation $({\mathbb{T}}={\mathbb{Z}})$ and for the general time-scale setting. An example is given to illustrate our results.  相似文献   

14.
In this paper we consider the following elliptic system in \mathbbR3{\mathbb{R}^3}
$\qquad\left\{{ll}-\Delta u+u+\lambda K(x)\phi u=a(x)|u|^{p-1}u \quad &x \in {\mathbb{R}}^{3}\\ -\Delta \phi=K(x)u^{2} \quad &x \in {\mathbb{R}}^{3}\right.$\qquad\left\{\begin{array}{ll}-\Delta u+u+\lambda K(x)\phi u=a(x)|u|^{p-1}u \quad &x \in {\mathbb{R}}^{3}\\ -\Delta \phi=K(x)u^{2} \quad &x \in {\mathbb{R}}^{3}\end{array}\right.  相似文献   

15.
Let Ω be an open, bounded domain in \mathbbRn  (n ? \mathbbN){\mathbb{R}^n\;(n \in \mathbb{N})} with smooth boundary ∂Ω. Let p, q, r, d 1, τ be positive real numbers and s be a non-negative number which satisfies 0 < \fracp-1r < \fracqs+1{0 < \frac{p-1}{r} < \frac{q}{s+1}}. We consider the shadow system of the well-known Gierer–Meinhardt system:
$ \left \{ {l@{\quad}l} \displaystyle{u_t = d_1\Delta u - u + \frac{u^p}{\xi^q}}, & \quad {\rm in}\;\Omega \times (0,T), \\ \displaystyle{\tau \xi_t = -\xi + \frac{1}{|\Omega|} \int\nolimits_\Omega\frac{u^r}{\xi^s} {\rm d}x}, & \quad {\rm in}\;(0,T), \\ \displaystyle{\frac{\partial u}{\partial \nu} =0}, & \quad {\rm on}\;\partial \Omega \times (0,T), \\ \displaystyle{\xi(0) = \xi_0 >0 , \quad u(\cdot,0) = u_0(\cdot)} \geq 0 & \quad {\rm in}\;\Omega. \right. $ \left \{ \begin{array}{l@{\quad}l} \displaystyle{u_t = d_1\Delta u - u + \frac{u^p}{\xi^q}}, & \quad {\rm in}\;\Omega \times (0,T), \\ \displaystyle{\tau \xi_t = -\xi + \frac{1}{|\Omega|} \int\nolimits_\Omega\frac{u^r}{\xi^s} {\rm d}x}, & \quad {\rm in}\;(0,T), \\ \displaystyle{\frac{\partial u}{\partial \nu} =0}, & \quad {\rm on}\;\partial \Omega \times (0,T), \\ \displaystyle{\xi(0) = \xi_0 >0 , \quad u(\cdot,0) = u_0(\cdot)} \geq 0 & \quad {\rm in}\;\Omega. \end{array} \right.  相似文献   

16.
The purpose of this article is to study the existence and uniqueness of global solution for the nonlinear hyperbolic-parabolic equation of Kirchhoff-Carrier type: $$ u_{tt} + \mu u_t - M\left (\int _{\Omega _t}|\nabla u|^2dx\right )\Delta u = 0\quad \hbox {in}\ \Omega _t\quad \hbox {and}\quad u|_{\Gamma _t} = \dot \gamma $$ where $ \Omega _t = \{x\in {\shadR}^2 | \ x = y\gamma (t), \ y\in \Omega \} $ with boundary o t , w is a positive constant and n ( t ) is a positive function such that lim t M X n ( t ) = + X . The real function M is such that $ M(r) \geq m_0 \gt 0 \forall r\in [0,\infty [ $ .  相似文献   

17.
This paper is concerned with power concavity properties of the solution to the parabolic boundary value problem $$\begin{aligned} (P)\quad \left\{ \begin{array}{l@{\quad }l} \partial _t u=\varDelta u +f(x,t,u,\nabla u) &{} \text{ in }\quad \varOmega \times (0,\infty ),\\ u(x,t)=0 &{} \text{ on }\quad \partial \varOmega \times (0,\infty ),\\ u(x,0)=0 &{} \text{ in }\quad \varOmega , \end{array} \right. \end{aligned}$$ where $\varOmega $ is a bounded convex domain in $\mathbf{R}^n$ and $f$ is a nonnegative continuous function in $\varOmega \times (0,\infty )\times \mathbf{R}\times \mathbf{R}^n$ . We give a sufficient condition for the solution of $(P)$ to be parabolically power concave in $\overline{\varOmega }\times [0,\infty )$ .  相似文献   

18.
In this paper we prove the L -boundedness of solutions of the quasilinear elliptic equation
$ {ll} Au \, = f(x,u,\nabla u) &\quad \rm{in }\, \Omega, \\ \dfrac{\partial u}{ \partial \nu} \, = g(x,u) &\quad \rm{on }\, \partial \Omega, $ \begin{array}{ll} Au \, = f(x,u,\nabla u) &\quad \rm{in }\, \Omega, \\ \dfrac{\partial u}{ \partial \nu} \, = g(x,u) &\quad \rm{on }\, \partial \Omega, \end{array}  相似文献   

19.
The paper proves the nonexistence of the solution for the following Cauchy problem\begin{align*}\begin{cases}u_{t} ={\rm div}\left(\left|\nabla u^{m} \right|^{p-2} \nabla u^{m} \right)-\lambda \; u^{q},&\qquad \left(x,t\right)\in S_{T} ={\mathbb{R}}^N \times \left(0,T\right), \\u\left(x,\; 0\right)=\delta \left(x\right), &\qquad x\in {\mathbb{R}}^,\end{cases}\end{align*}under some conditions on \textit{m,p,q},$\lambda$, where $\delta $ is Dirac function.  相似文献   

20.
We study the radially symmetric Schr?dinger equation
$ - \varepsilon ^{2} \Delta u + V{\left( {|x|} \right)}u = W{\left( {|x|} \right)}u^{p} ,\quad u > 0,\;\;u \in H^{1} ({\mathbb{R}}^{N} ), $ - \varepsilon ^{2} \Delta u + V{\left( {|x|} \right)}u = W{\left( {|x|} \right)}u^{p} ,\quad u > 0,\;\;u \in H^{1} ({\mathbb{R}}^{N} ),  相似文献   

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