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一类特殊的组合数——线组合数
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作者 张静远 《科技信息》 2009年第28期94-94,共1页
作者引进了线组合数的概念,获得了线组合数几个恒等式。
关键词 组合 圆组合数 线组合
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The Filtration Problems of Fluid Containing Solute Through Layered Porous Media
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作者 邓聚成 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第3期77-87,共11页
In this paper, we consider the problem (θ(x,U))_t=(K(x,U)U_x)_x-(K(x,U))_x (x,t)∈G_T (θ(x,U)V(x,t))_t=(DθV_x)_x+(V(KU_x-K))_x,(x,t)∈G_T, u(x,0)=u_0(x),V(x,0),(x,0)=V_0(x),0≤x≤2, U(0,t)=h_0(t),U(2,t)=h_2(t),0≤t... In this paper, we consider the problem (θ(x,U))_t=(K(x,U)U_x)_x-(K(x,U))_x (x,t)∈G_T (θ(x,U)V(x,t))_t=(DθV_x)_x+(V(KU_x-K))_x,(x,t)∈G_T, u(x,0)=u_0(x),V(x,0),(x,0)=V_0(x),0≤x≤2, U(0,t)=h_0(t),U(2,t)=h_2(t),0≤t≤T, V(0,t)=g_0(t),V(2,t)=g_2(t),0≤t≤T. Where, θ(x,U)=θ_1(x,U) when (x,t)∈D_1={0≤x<1,0≤t≤T};θ(x,U)=θ_2(x,U),(x,t)∈D_2={1<x≤2,0≤t≤T}.K(x,U)=K_i(x,U),(x,t)∈D_i. θ_i, K_i are the Moisture content and hy draulic conductivity of porous Media on D_i respectively. V be the the concentration of solute in the fluid. In addition we also require that U, V, (K(x,U)U_x-1) and DθV_x+V(KU_x-K) are continu ous at x=1. We prove the exisence, uniqueness and large time behavior of the problem by the method of reg ularization. 展开更多
关键词 porous Media FILTRATION weak solution
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Linear Combination of Derivative Weighted Composition Operators
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作者 TONG Cezhong GENG Ligang 《Transactions of Tianjin University》 EI CAS 2012年第1期69-72,共4页
The relation between composition operators on the Dirichlet spaces in the open unit disk and derivative weighted composition operators on the Bergman spaces in the open unit disk is investigated firstly,and for a comb... The relation between composition operators on the Dirichlet spaces in the open unit disk and derivative weighted composition operators on the Bergman spaces in the open unit disk is investigated firstly,and for a combination of several derivative weighted composition operators which acts on classic Bergman space,the lower bound of its essential norm is estimated in terms of the boundary data of the symbols of d-composition operators.Some similar results about composition operators on the Dirichlet space are also presented.A necessary condition is given to determine the compactness of the combination of several derivative weighted composition operators on Bergman spaces. 展开更多
关键词 derivative weighted composition operator Bergman space Dirichlet space essential norm
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