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1.
本文研究了不可压磁流体方程组弱解的正则性准则,设(u(t,x),6(t,x))是不可压磁流体方程组在(O,T)上的光滑解,如果旋度和电流密度满足(▽× u,▽× b) ∈ L 2-a/2 (O, T;B-aa∞, ∞(R3)) ηL1-a/2(O,T;B-∞1,-a∞(R3)),0<α<1,则光滑解(u(t,x),b(t,x))可以连续延拓到(O,T'),T'>T.而且这个条件可以保证满足能量不等式的弱解是(O,T)上的光滑解.  相似文献   

2.
利用能量估计与不等式研究三维广义Navier-Stokes方程弱解的正则性准则,证明如果速度场的水平分量ū=(u1,u2,0)满足ū∈L2α-(r+1)2α(0,T;r),r∈[0,1),或者水平速度场的水平梯度▽hū=(α1ū,α2ū)满足▽hū∈L2α-r2α(0,T;r),r∈[0,1],则弱解在[0,T)是唯一的强解.  相似文献   

3.
该文研究椭圆型方程{-Δpu+m|u|p-2u-Δqu+n|u|q-2u=g(x,u),x∈RN,u∈ W1,p(RN)∩W1,q(RN)弱解在全空间RN上的衰减性,其中m,n≥0,N≥3,1相似文献   

4.
本文研究了非线性抛物方程弱解的L2 衰减 ,证明了若u是非线性抛物方程的一个弱解 ,则u满足‖u‖L2 ≤C( 1 t) -n/ 4,其中C是常数且仅依赖于初始值u0 的范数 .  相似文献   

5.
研究奇异拟线性椭圆型方程{-div(|x|~(-ap)|▽u|~(p-2)▽u) + f(x)|u|~(p-2) = g(x)\u|~(q-2)u + λh(x)|u|~(r-2),x R~N,u(x) 0,x∈ R~N,其中λ0是参数,1pN(N3),1rpgp*=0a(N—p)/p,p*=Np/{N~pd),aa+l,d=a+l-60,权函数f(x),g(x),h(x)满足一定的条件.利用山路引理和Ekeland变分原理证明了问题至少有两个非平凡的弱解.  相似文献   

6.
以■记全体标准p-函数,设固定p_0∈■且0相似文献   

7.
Let u =(uh, u3) be a smooth solution of the 3-D Navier-Stokes equations in R3× [0, T). It was proved that if u3 ∈ L∞(0, T;˙B-1+3/p p,q(R3)) for 3 p, q ∞ and uh∈ L∞(0, T; BMO-1(R3)) with uh(T) ∈ VMO-1(R3), then u can be extended beyond T. This result generalizes the recent result proved by Gallagher et al.(2016), which requires u ∈ L∞(0, T;˙B-1+3/pp,q(R3)). Our proof is based on a new interior regularity criterion in terms of one velocity component, which is independent of interest.  相似文献   

8.
本文主要考虑三维广义Navier-Stokes方程的衰减率,其分数阶耗散项为Λu.我们证明,如果三维广义Navier-Stokes方程的弱解u(x,t)属于下面正则集▽u∈Lp(0,∞;Bq,∞0(R3)),2α/p+3/q=2α,3/2α0∈L2(R3)满足:∫s2|w0(rω)|2dω=Cr2αγ-3+o(r2αγ-3)(r→0),10/α-8≤γ≤25/2α-10.则其扰动方程的每个弱解v(x、t)以最优的上下界依代数收敛到u(x,t),C1(1+t)-γ/2≤‖v(t)-u(t)‖L2≤C2...  相似文献   

9.
利用Stokes算子的谱分解方法和线性Lp-Lq估计研究一类三维不可压缩非牛顿流体弱解的最优代数衰减速率,证明了当初速度满足u0∈L2(R3)和∫R3(1+|x|)|u0(x)|dx∞,其弱解在L2范数下的衰减率为t-5/4.  相似文献   

10.
在W1,p(x)空间框架下研究了具有p(x)增长条件的椭圆型偏微分方程:-d iva(x,u,D u) g(x,u,u)=f,得到了在W10,p(x)空间中弱解的存在性,推广了Boccardo等关于在Sobo lev空间中弱解的相应结论.  相似文献   

11.
This paper is concerned with the parabolic equation $\frac{\partial u}{\partial t}-div(|\bigtriangledown u|^{p-2}\bigtriangledown u)=0,x\in \Omega \subseteqq R^n,t>0$ with $p>max{3/2,2N/(N+2)}$ which is degenerate if p<2 er singular if 3/2相似文献   

12.
We consider the general initial-boundary value problem

(1)        
(2)        
(3)        
where is a bounded open set in with sufficiently smooth boundary.  The problem (1)-(3) is first reduced to the analogous problem in the space with zero initial condition and


The resulting problem is then reduced to the problem where the operator satisfies Condition  This reduction is based on a priori estimates which are developed herein for linear parabolic operators with coefficients in Sobolev spaces.  The local and global solvability of the operator equation are achieved via topological methods developed by I. V. Skrypnik. Further applications are also given involving relevant coercive problems, as well as Galerkin approximations.

  相似文献   


13.
Summary In this paper we study the noncharacteristic Cauchy problem, ut–(a(x)ux)x=0, x(0, l), t.(0, T], u(0, t)=(t), ux(0,t)=0, 0tT, assuming only L for a. In the case of weak a priori bounds on u, we derive stability estimates on u of Hölder type in the interior and of logarithmic type at the boundary. Also the continuous dependence on a is considered.
Sunto Nel presente lavoro consideriamo il problema di Cauchy non ben posto ut= (a(x)ux)x, x(0, l), t(0, T), u(0, t)=(t), ux(0, t)=0, 0tT. Supponiamo che a sia misurabile e limitato inferiormente e superiormente da constanti positive. Introduciamo delle limitazioni a priori su u e dimostriamo la dipendenza continua di u rispetto al dato sia in (0, l)×(0, T) (di tipo hölderiano) sia per x=l (di tipo logaritmico). Consideriamo, inoltre, la dipendenza continua di u da a.
  相似文献   

14.
本文处理带非线性边界条件 u n=uα, v n=vβ ,(x ,t) ∈ Ω× (0 ,T)的抛物方程组ut =vpΔu ,vt=uqΔv ,(x ,t) ∈Ω× (0 ,T) ,其中Ω RN 为一个有界区域 ,p ,q>0和α ,β≥ 0为常数 .研究了上述问题正解的整体存在性和爆破 ,建立了整体存在和爆破的新标准 .证明了当max{p+β,q+α}≤ 1时正解 (u ,v)整体存在 ,当min{p+β ,q+α}>1且max{α ,β}<1时正解 (u ,v)在有限时刻爆破  相似文献   

15.
Let L be the language of the intuitionistic propositional calculus J completed by the quantifiers and , and let calculus 2J in language L contain, besides the axioms of J, the axioms xB (x) B(y) and B(y) xB (x). A Kripke semantics is constructed for 2J and a completeness theorem is proven. A result of D. Gabbay is generalized concerning the undecidability of C2J+-extension of 2J by schemes x (x B) and x(A B(x))A xB (x) specificially: the undecidability is proven of each T theory in language L such that [2J]T [C2J+] ([2J] ([2J] denotes the set of all theorems of calculus 2J).Translated from Matematicheskie Zametki, Vol. 22, No. 1, pp. 69–76, July, 1977.  相似文献   

16.
Motivated by the results of J.Y.Chemin in "J.Anal.Math.,77,1999,27-50" and G.Furioli et al in "Revista Mat.Iberoamer.,16,2002,605-667",the author considers further regularities of the mild solutions to Navier-Stokes equation with initial data u0∈Ld(Rd).In particular,it is proved that if u∈C([0,T*); Ld(Rd)) is a mild solution of (NSv),then u(t,x) -evt△u0∈(L)∞ ((0,T); (B)1/d/2,∞)∩(L)1((0,T);(B)3/d/2,∞) for any T<T*.  相似文献   

17.
In this paper, some improved regularity criteria for the 3D magneto-micropolar fluid equations are established in Morrey–Campanato spaces. It is proved that if the velocity field satisfies
$\quad u\in L^{\frac{2}{1-r}}\left(0,T;\overset{.}{\mathcal{M}}_{p,\frac{3}{r}}( \mathbb{R}^{3})\right)\quad\text{with} \;r\in \left( 0,1\right)\;\text{or}\;u\in C\left(0,T;\overset{.}{\mathcal{M}}_{p,\frac{3}{r}}(\mathbb{R} ^{3})\right)$\quad u\in L^{\frac{2}{1-r}}\left(0,T;\overset{.}{\mathcal{M}}_{p,\frac{3}{r}}( \mathbb{R}^{3})\right)\quad\text{with} \;r\in \left( 0,1\right)\;\text{or}\;u\in C\left(0,T;\overset{.}{\mathcal{M}}_{p,\frac{3}{r}}(\mathbb{R} ^{3})\right)  相似文献   

18.
By employing the generalized Riccati transformation technique, we will establish some new oscillation criteria and study the asymptotic behavior of the nonoscillatory solutions of the second-order nonlinear neutral delay dynamic equation
, on a time scale . The results improve some oscillation results for neutral delay dynamic equations and in the special case when = ℝ our results cover and improve the oscillation results for second-order neutral delay differential equations established by Li and Liu [Canad. J. Math., 48 (1996), 871–886]. When = ℕ, our results cover and improve the oscillation results for second order neutral delay difference equations established by Li and Yeh [Comp. Math. Appl., 36 (1998), 123–132]. When =hℕ, = {t: t = q k , k ∈ ℕ, q > 1}, = ℕ2 = {t 2: t ∈ ℕ}, = = {t n = Σ k=1 n , n ∈ ℕ0}, ={t 2: t ∈ ℕ}, = {√n: n ∈ ℕ0} and ={: n ∈ ℕ0} our results are essentially new. Some examples illustrating our main results are given.   相似文献   

19.
Let us consider a signal-plus-noise model h(z)+B 0(z), z [0,1], where > 0, h: [0,1] , and B 0 is a Brownian bridge. We establish the asymptotics for the boundary crossing probability of the weighted signal-plus-noise model for , that is P (sup z [0,1] w(z)( h(z)+B 0(z))>c), for , (1) where w: [0,1] [0, is a weight function and c>0 is arbitrary. By the large deviation principle one gets a result with a constant which is the solution of a minimizing problem. In this paper we show an asymptotic expansion that is stronger than large deviation. As byproduct of our result we obtain the solution of the minimizing problem occurring in the large deviation expression. It is worth mentioning that the probability considered in (1) appears as power of the weighted Kolmogorov test applied to the test problem H 0: h 0 against the alternative K: h>0 in the signal-plus-noise model.  相似文献   

20.
We study the effective heat conductivity of regular arrays of perfectly conducting spheres embedded in a matrix with unit conductivity. Quasifractional approximants allow us to derive an approximate analytical solution, valid for all values of the spheres volume fraction [0, max] (max is the maximum volume fraction of a spheres). As a starting point we use a perturbation approach for 0 and an asymptotic solution for max. Three different spatial arrangements of the spheres, simple cubic, body centred and face centred cubic arrays, are considered. Results obtained give a good agreement with numerical data.  相似文献   

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