检索结果-南通市图书馆

Local orthogonal transform for a class of acoustic waveguides

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第10期17卷 1136-1146页

作者： Zhu Jianxin and Li Peng(department of mathematics, zhejiang University,{2., china) department of mathematics Zhejiang University Hangzhou 310027 China

There are some curved interfaces in acoustic waveguides. To compute wave propagation along the waveguides with some marching methods, flattening of the internal interfaces is needed. In this paper, a local orthogonal coordinate transform and an equation transform are constructed to solve the two-dimensional Helmholtz equation for the waveguides bounded by a flat top, a flat bottom and two curved internal interfaces with three layered media. The curved internal interfaces are flattened by the local orthogonal coordinate transform, and the corresponding transformed Helmholtz equation can be solved by some marching methods. This treatment can be extended in multilayered medium waveguides. The one-way reformulation based on the Dirichlet-to-Neumann (DtN) map is then used to reduce the boundary value problem to an initial value problem. Numerical implementation of the resulting operator Riccati equation uses a large range step method to discretize the range variable and a truncated local eigenfunction expansion to approximate the operators. This method is particularly useful for solving long range wave propagation problems in slowly varying waveguides with multilayered medium structure.

关键词： Helmholtz equation local orthogonal transform DtN reformulation marching method internal interface one-way reformulation.

Functional limit theorem for moving average processes generated by dependent random variables

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第3期16卷 266-273页

作者： LIN Zhengyan and LI Degui (department of mathematics, zhejiang University,{2., china) [a]department of mathematics Zhejiang University Hangzhou China

Let {Xt,t≥1} be a moving average process defined by , where {bj,j≥0} is a sequence of real num- bers and {ξt,-∞ 详细信息

Let {Xt,t≥1} be a moving average process defined by , where {bj,j≥0} is a sequence of real num- bers and {ξt,-∞

关键词： functional limit theorem long memory process linear process moving average process φ-mixing.

A note on certain square functions on product spaces

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china mathematics 2006年第1期49卷 98-108页

作者： WANG Meng, CHEN Jiecheng2.& FAN Dashan department of mathematics, zhejiang University (at Yuquan campus),{2., china department of mathematics, zhejiang University (at Xixi campus),{2., china department of mathematics, University of Wisconsin-Milwaukee, Milwaukee, WI532.1, USA department of mathematics Zhejiang University [at Yuquan campus] Hangzhou 310027 China department of mathematics Zhejiang University [at Xixi campus] Hangzhou 310028 China department of mathematics University of Wisconsin-Milwaukee Milwaukee WI53201 USA

We study certain square functions on product spaces Rn × Rm, whose integral kernels are obtained from kernels which are homogeneous in each factor Rn and Rm and locally in L(log+ L) away from Rn × {0} and {0} × Rm by means of polynomial distortions in the radial variable. As a model case, we obtain that the Marcinkiewicz integral operator is bounded on Lp(Rn × Rm)(P > 1) for Ω∈ e Llog+ L(Sn-1 × Sm-1) satisfying the cancellation condition.

关键词： square function, Marcinkiewicz integral, product space.

The Cauchy Integral Operator on Weighted Hardy Space

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 2010年第4期31卷 461-472页

作者： Jianmiao RUAN Jiecheng CHEN department of mathematics Zhejiang University Hangzhou 310027 China department of mathematics Zhejiang Education Institute Hangzhou 310012 China

The authors show that the Cauchy integral operator is bounded from Hωp(R1) to hωp(R1) (the weighted local Hardy space). To prove the results, a kind of generalized atoms is introduced and a variant of weighted "Tb t... 详细信息

关键词： Cauchy integral Calder6n-Zygmund operator Weighted Hardy space Weighted local Hardy space

Transitional function of DG to CA3 in the hippocampus

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第12期17卷 1436-1444页

作者： Yan Chuankui1 and Liu Shenquan2.1. department of mathematics, hangzhou Normal University, hangzhou 310036, china 2. department of Applied mathematics, School of Mathematical Sciences, South china University of Technology, Guangzhou 510640, china) department of mathematics Hangzhou Normal University Hangzhou 310036 China department of Applied mathematics School of Mathematical Sciences South China University of Technology Guangzhou 510640 China

Using single cell channel model, the transmission features of CA3-DG network in the hippocampus are investigated. The influence of the stimulation on discharge pattern of pyramidal neurons is analyzed, which shows that it starts with period spiking discharges, followed by period-doubling bifurcation to chaos, and period 3 discharge evolving into chaos, and ultimately a period of bursting discharges. By the synaptic model, the CA3-DG network model is constructed, which analyzes the summation of postsynaptic currents in the network, the influence of postsynaptic current on discharge rhythm as well as the mechanism of bursting discharges. The strong capacity of spatiotemporal encoding in the network indicates the features of CA3 network during the information transmission process in the hippocampus. The modeling result with time delay of the synaptic transmission is in accordance with the experimental phenomena of action potential in the hippocampus.

关键词： hippocampus CA3-DG period-doubling bifurcation chaos.

On Holomorphic Automorphisms of a Class of Non-homogeneous Rigid Hypersurfaces in C^(N+1)

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 2010年第2期31卷 201-210页

作者： Qingyan WU department of mathematics,Linyi Normal University,Linyi 2.6005,Shandong,china department of mathematics,zhejiang University,hangzhou 31002.,china department of mathematics Linyi Normal University Linyi 276005 Shandong China department of mathematics Zhejiang University Hangzhou 310027 China

The author determines the real-analytic infinitesimal CR automorphisms of a class of non-homogeneous rigid hypersurfaces in CN+1 near the origin,and the connected component containing the identity transformation of al... 详细信息

关键词： Real-analytic infinitesimal CR automorphisms Rigid hypersurfaces Holomorphic automorphisms

Almost sure central limit theorems for random functions

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2006年第12期49卷 1788-1799页

作者： LU Chuanrong, QIU Jin & XU Jianjun School of mathematics and Statistics, zhejiang University of Finance and Economics, {2. 310018, china department of mathematics, zhejiang University, hangzhou 31002., china 1. School of mathematics and Statistics Zhejiang University of Finance and Economics Hangzhou 310018 China 2. department of mathematics Zhejiang University Hangzhou 310028 China

Let {Xn,-∞< n <∞} be a sequence of independent identically distributed random variables with EX1 = 0, EX12.= 1 and let Sn =∑k=1∞Xk, and Tn = Tn(X1,…,Xn) be a random function such that Tn = ASn + Rn, where supn E|... 详细信息

Let {Xn,-∞2.= 1 and let Sn =∑k=1∞Xk, and Tn = Tn(X1,…,Xn) be a random function such that Tn = ASn + Rn, where supn E|Rn| 2.) a.s., or Rn = O(n1/2.2.) a.s., 0 <γ< 1/8. In this paper, we prove the almost sure central limit theorem (ASCLT) and the function-typed almost sure central limit theorem (FASCLT) for the random function Tn. As a consequence, it can be shown that ASCLT and FASCLT also hold for U-statistics, Von-Mises statistics, linear processes, moving average processes, error variance estimates in linear models, power sums, product-limit estimators of a continuous distribution, product-limit estimators of a quantile function, etc.

关键词： statistics,random function,almost sure central limit theorem,logarithm average.

ON CONVERGENCE OF NOUREIN ITERATIONS FOR SIMULTANEOUS FINDING ALL ZEROS OF A POLYNOMIAL

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 2000年第2期18卷 113-122页

作者： Shi-mingZheng Zheng-da Huang (department of mathematics, Xixi Campus, zhejiang University,{2., china) 浙江大学浙江杭州 310028

Presents the first estimation conditions for Nourein iterations for simultaneous finding all zeros of a polynomial under which the iteration processes are guaranteed to converge. Computational formulas; Theorems and p... 详细信息

关键词： polynomial zeros parallel iteration Nourein iterations point estimation convergence

Synthesis and crystal structure of complex of Ce(NO_3)_3 with N-(3-methyl-pyridin-2.yl)-formimidoyl-(3-methyl-pyridin-2.yl) hydrazone

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2004年第3期47卷 251-256页

作者： JIANG Yinzhi1,2.& HU Weixiao1 1. department of Pharmaceutical Science, zhejiang University of Technology, {2. 310032. china 2. department of Applied Chemistry, zhejiang Institute of Science and Technology, {2. 310033, china 1. department of Pharmaceutical Science Zhejiang University of Technology 310032 Hangzhou China 2. department of Applied Chemistry Zhejiang Institute of Science and Technology 310033 Hangzhou China

The reaction of 3,6-di-(3-methyl-pyridin-2.yI)-s-tetrazine (DMPTZ, II) with CeIII salt [Ce(NO3)3 · 6H2.] generates a new ligand, N-(3-methyl-pyridin-2.yl)-formimidoyl-(3-methyl-pyridin-2.yl) hydrazone (L), and forms a new complex: a mononuclear complex [Ce(L)(NO3)2.(H2.)3] · NO3 (III). Crystal data for III: space group P-1, with a = 0.7133(4) nm, b = 1.1139(2. nm, c = 1.4572.3) nm, α= 102.13(2.°, β= 99.81(3)°, γ= 91.10(3)°, Z = 2. V = 1113.6(7) nm3, μ = 2.12. mm?1 and F(000) = 630. L acts as a tri-dentate chelating ligand in III. There are 10 coordination sites around Ce3+ of III, which are respectively occupied by seven oxygen atoms (four from two nitrate anions and three from three H2. molecules) and three nitrogen atoms (all from L). The cerium atom and three chelating nitrogen atoms are coplanar. The mechanism of the metal assisted decomposition is discussed briefly.

关键词： rare earth, complex, crystal structure, synthesize, 3,6-bis (3-methyl-pyridin-2.yl)-s-tetrazine, N-(3-methyl-pyridin- 2.yl)-formimidoyl-(3-methyl-pyridin-2.yl) hydrazone.