检索结果-南通市图书馆

Oblique derivative problem for general Chaplygin-Rassias equations

Science China Mathematics 2008年第1期51卷 5-36页

作者： WEN GuoChun LMAM, School of mathematical sciences, peking university, {3., China LMAM School of Mathematical Sciences Peking University Beijing 100871 China

The present paper deals with the oblique derivative problem for general second order equations of mixed (elliptic-hyperbolic) type with the nonsmooth parabolic degenerate line $$K_1 (y)u_{xx} + \left| {K_2 (x)} \right|u_{yy} + a(x,y)u_x + b(x,y)u_y + c(x,y)u = - d(x,y)$$ in any plane domain D with the boundary ?D=Γ ∪ L 1 ∪ L 2 ∪ L 3.∪ L 4. where Γ(? {y > 0}) ∈ C μ 2 (0 2, L 3. L 4.are four characteristics with the slopes ?H 2(x)/H 1(y), H 2(x)/H 1(y),?H 2(x)/H 1(y),H 2(x)/H 1(y) (H 1(y) = √|K 1(y)|, H 2(x) = √|K 2(x)| in {y 3.3.\frac{{\partial u}}{{\partial \nu }} = \frac3.{{H(x,y)}}\operatorname{Re} \left[ {\overline {\lambda (z)} u_{\tilde z} } \right] = r(z), z \in \Gamma \cup L_1 \cup L_4., \operatorname{Im} \left[ {\overline {\lambda (z)} u_{\tilde z} } \right]\left| {_{z = z_l } } \right. = b_l ,l = 1,2, u( - 1) = b_0 ,u(1) = b_3.,$$ in which z 1, z 2 are the intersection points of L 1, L 2, L 3. L 4.respectively. The above equations can be called the general Chaplygin-Rassias equations, which include the Chaplygin-Rassias equations $$K_1 (y)(M_2 (x)u_x )_x + M_1 (x)(K_2 (y)u_y )_y + r(x,y)u = f(x,y), in D$$ as their special case. The above boundary value problem includes the Tricomi problem of the Chaplygin equation: K(y)u xx+u yy = 0 with the boundary condition u(z) = ?(z) on Γ ∪ L 1 ∪ L 4.as a special case. Firstly some estimates and the existence of solutions of the corresponding boundary value problems for the degenerate elliptic and hyperbolic equations of second order are discussed. Secondly, the solvability of the Tricomi problem, the oblique derivative problem and Frankl problem for the general Chaplygin-Rassias equations are proved. The used method in this paper is different from those in other papers, because the new notations W(z) = W(x + iy) = $u_{\tilde z} $ = [H

关键词： oblique derivative problem equations of mixed type nonsmooth degenerate line 3.J70 3.L80 3.N99

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Global well-posedness for the 2D critical dissipative quasi-geostrophic equation

引用

Science China Mathematics 2007年第4期50卷 485-494页

作者： Zhi-fei ZHANG School of mathematical sciences, peking university, {3., China School of mathematical sciences Peking University Beijing 100871 China

We study the initial value problem for the 2D critical dissipative quasi-geostrophic equation. We prove the global existence for small data in the scale invariant Besov spaces ? p,1 2/p , 1 ? p ? ∞. In particular, for p = ∞, our result does not impose any regularity on the initial data. Our proofs are based on an exponential decay estimate of the semigroup $e^{{ - t\kappa ( - \Delta )}^{\alpha}} $ and the use of space-time Besov spaces.

关键词： quasi-geostrophic equation Besov space Littlewood-Paley decomposition well-posedness 3.Q3.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Maslov-type index and brake orbits in nonlinear Hamiltonian systems

引用

Science China Mathematics 2007年第6期50卷 761-772页

作者： Duan-zhi ZHANG School of mathematical sciences, peking university, {3., China 1. School of mathematical sciences Peking University Beijing 100871 China

In this paper, we study the Maslov-type index theory for linear Hamiltonian systems with brake orbits boundary value conditions and its applications to the existence of multiple brake orbits of nonlinear Hamiltonian s... 详细信息

关键词： brake orbit Maslov-type index relative Morse index dual variational method 58E05 70H05 3.C25

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Finite Groups in Which Sylow Normalizers Admit Supplements

引用

Acta Mathematica Sinica,English Series 2007年第3期23卷 417-422页

作者： Tian Ze LI School of mathematical sciences,peking university,{3.,P.R.China School of mathematical sciences Peking University Beijing 100871 P. R.China

For a group G and a subgroup M of G,we say that a subgroup A of G is a supplement toM in G,if G=*** prove that a finite group in which every Sylow normalizer admits a nilpotentsupplement is *** particular we confirm a... 详细信息

关键词： Sylow normalizer Supplement Wreath product

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A　Diference　Scheme　with　Anti－difusion　Terms　to　Improve　the　Computation　of　Contact　Discontinuities　and　the　Study　of　Weak　Discontinuities　in　Compresible　Flow

引用

Communications in Nonlinear Science and Numerical Simulation 1996年第4期1卷 42-51页

作者： Chunguang XU (College of mathematical Science ,peking university, beijing 100871) College of mathematical Science peking university beijing 100871 USA

Ａｂｓｔｒａｃｔ：ＴｈｅｉｎｖｅｓｔｉｇａｔｉｏｎｏｆＭａｃｈｒｅｆｌｅｃｔｉｏｎｆｏｒｍｅｄａｆｔｅｒｔｈｅｉｍｐｉｎｇｅｍｅｎｔｏｆａｗｅａｋｐｌａｎｅｓｈｏｃｋｗａｖｅｏｎａｗｅｄｇｅ，ｗｉｔｈｓｈｏｃｋＭａｃ... 详细信息

Ａｂｓｔｒａｃｔ：ＴｈｅｉｎｖｅｓｔｉｇａｔｉｏｎｏｆＭａｃｈｒｅｆｌｅｃｔｉｏｎｆｏｒｍｅｄａｆｔｅｒｔｈｅｉｍｐｉｎｇｅｍｅｎｔｏｆａｗｅａｋｐｌａｎｅｓｈｏｃｋｗａｖｅｏｎａｗｅｄｇｅ，ｗｉｔｈｓｈｏｃｋＭａｃｈｎｕｍｂｅｒＭｓｎｅａｒ１，ｉｓｓｔｉｌａｎｏｐｅｎｐｒｏｂｌｅｍ［１２］．Ｉｔ＇ｓｄｉｆｉｃｕｌｔｆｏｒｓｈｏｃｋｔｕｂｅｅｘｐｅｒｉｍｅｎｔｓｗｉｔｈｉｎｔｅｒｆｅｒｏｍｅｔｅｒｔｏｄｅｔｅｃｔｃｏｎｔａｃｔｄｉｓｃｏｎ－ｔｉｎｕｉｔｉｅｓ，ｉｆｉｔｉｓｔｏｏｗｅａｋ；ａｌｓｏｄｉｆｉｃｕｌｔｔｏｃａｔｃｈｗｉｔｈｄｕｅａｃｃｕｒａｃｙｔｈｅｔｒａｎｓｉｔｉｏｎｃｏｎｄｉｔｉｏｎｂｅｔｗｅｅｎＭａｃｈｒｅｆｌｅｃｔｉｏｎａｎｄｒｅｇｕｌａｒｒｅｆｌｅｃｔｉｏｎ．Ｔｈｅｉｎｔｅｒｅｓｔｔｏｔｈｉｓｐｈｅｎｏｍｅｎｏｎｉｓｃｏｎｔｉｎ－ｕｉｎｇ，ｅｓｐｅｃｉａｌｙｆｏｒｗｅａｋｓｈｏｃｋｓ，ｂｅｃａｕｓｅｔｈｅｒｅｗａｓｓｙｓｔｅｍａｔｉｃｄｉｓｃｒｅｐａｎｃｙｂｅｔｗｅｅｎｓｉｍ－ｐｌｉｆｉｅｄｔｈｒｅｅｓｈｏｃｋｔｈｅｏｒｙｏｆｖｏｎＮｅｕｍａｎｎ［８］ａｎｄｓｈｏｃｋｔｕｂｅｒｅｓｕｌｔ

关键词： weak reflection Mach reflection anti-diffusion

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

OBLIQUE DERIVATIVE PROBLEMS FOR SECOND ORDER NONLINEAR MIXED EQUATIONS WITH DEGENERATE LINE

引用

Acta Mathematica Scientia 2008年第3期28卷 604-612页

作者：闻国椿 School of mathematical sciences Peking University

The present article deals with oblique derivative problems for some nonlinear mixed equations with parabolic degeneracy, which include the Tricomi problem as a special case. First, the formulation of the problems for the equations is given; next, the representation and estimates of solutions for the above problems are obtained; finally, the existence of solutions for the problems is proved by the successive iteration and the compactness principle of solutions of the problems. In this article, the author uses the complex method, namely, the complex functions in the elliptic domain and the hyperbolic complex functions in hyperbolic domain are used.

关键词： Oblique derivative problems nonlinear mixed equations parabolic degeneracy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The lifting scheme of 4.channel orthogonal wavelet transforms

引用

Progress in Natural Science:Materials International 2006年第1期16卷 100-104页

作者： PENG Lizhong and CHU Xiaoyong (LMAM, School of mathematical sciences, peking university, {3., China) [a]peking Universiy LMAM School of Mathematical Sciences Beijing China

The 4.channel smooth wavelets with linear phase and orthogonality are designed from the 2-channel orthogonal wavelets with high transfer vanishing moments. Reversely, for simple lifting scheme of such 4.channel orthogonal wavelet transforms, a new 2-channel orthogonal wavelet associated with this 4.channel wavelet is constructed. The new 2-channel wavelet has at least the same number of vanishing moments as the associated 4.channel one. Finally, by combining the two such 2-channel wavelet systems, the lifting scheme of 4.channel orthogonal wavelet transform, which has simple structure and is easy to apply, is presented.

关键词： lifting scheme 4.channel orthogonal wavelet 2-channel orthogonal wavelet vanishing moment transfer vanishing moment linear phase.

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

r-matrix and algebraic-geometric symplectic map

引用

Chinese Science Bulletin 1999年第2期44卷 114-118页

作者： QIAO ZhijunInstitute of Mathematics and School of mathematical sciences, peking university, {3., China Institute of Mathematics and School of mathematical sciences Peking University Beijing China

A new Lax matrix is introduced for the integrable symplectic map (ISM), and the non-dynamical(i. e. constant) r-matrix of ISM is obtained. Moreover, an effective approach is systematically presented to construct the explicit solution(here, the explicit solution means algebraic-geometric solution expressed by the Riemann-Theta function) of a soliton system or nonlinear evolution equation from Lax matrix, r-matrix, and the theory of nonlinearization through taking the Toda lattice as an example. The given algebraic-geometric solution of the Toda lattice is almost-periodic and includes the periodic and finite-band solution.

关键词： symplectic map r-matrix algebraic-geometric solution.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

SOME BOUNDARY VALUE PROBLEMS FOR NONLINEAR DEGENERATE ELLIPTIC EQUATIONS OF SECOND ORDER

引用

Acta Mathematica Scientia 2007年第3期27卷 663-672页

作者：闻国椿 School of mathematical sciences Peking University

The present article deals with some boundary value problems for nonlinear elliptic equations with degenerate rank 0 including the oblique derivative problem. Firstly the formulation and estimates of solutions of the oblique derivative problem are given, and then by the above estimates and the method of parameter extension, the existence of solutions of the above problem is proved. In this article, the complex analytic method is used, namely the corresponding problem for degenerate elliptic complex equations of first order is firstly discussed, afterwards the above problem for the degenerate elliptic equations of second order is solved.

关键词： Boundary value problems nonlinear elliptic equations parabolic degeneracy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

ON THE CENTRAL RELAXING SCHEME Ⅱ: SYSTEMS OF HYPERBOLIC CONSERVATION LAWS

引用

Journal of Computational Mathematics 2001年第6期19卷 571-582页

作者： Hua-zhong Tang (School of mathematical sciences, peking university, {3., China) (LSEC,ICMSEC Academy of Mathematics and Systems sciences, Chinese Academy of sciences, beijing 100080, China) School of mathematical sciences Peking University Beijing 100871 China

This paper continues to study the central relaxing schemes for system of hyperbolic conservation laws, based on the local relaxation approximation. Two classes of relaxing systems with stiff source term are introduced to approximate system of conservation laws in curvilinear coordinates. Based on them, the semi-implicit relaxing schemes are con- structed as in [6, 12] without using any linear or nonlinear Riemann solvers. Numerical experiments for one-dimensional and two-dimensional problems are presented to demon- strate the performance and resolution of the current schemes.

关键词： Hyperbolic conservation laws The relaxing system The central relaxing schemes The Euler equations.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：