检索结果-南通市图书馆

The Journal of china Universities of posts and Telecommunications 2004年第z1期11卷 55-61页

作者： LI Zuo-wei~1, YANG Yi-xian~1, YUAN Dong-feng~2, HU Zheng-ming~1 1.information Security Center,Beijing university of posts and Telecommunications, Beijing 100876, p.r. china 2.school of information science and engineering, shandong university, jinan 250100, p.r. china information Security Center Beijing University of Posts and Telecommunications Beijing 100876 P.R. China school of information science and engineering Shandong University Jinan 250100 P.R. China

In this pap.r. we propose a novel Unequal Error protection (UEp) scheme with two levels for image transmission using Multilevel Codes (MLC). By providing the best protection for the most imp.r.ant data, the final recovered image quality is remarkably improved both in visual effect and in peak Signal to Noise power ratio (pSNr) p.r.ormance.

关键词： rayleigh fading channel image transmission inequal error protection multilevel coding

LEAST-SQUArES MIXED FINITE ELEMENT METHODS FOr NONLINEAr p.r.BOLIC prOBLEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2002年第2期20卷 153-164页

作者： Dan-ping Yang (school of Mathematics and System science, shandong university, jinan 250100, china) school of Mathematics and System science Shandong University Jinan 250100

Focuses on the formulation of a number of least-squares mixed finite element schemes to solve the initial boundary value problem of a nonlinear p.r.bolic p.r.ial differential equation. Convergence analysis; Informatio... 详细信息

关键词： least-squares algorithm mixed finite element nonlinear p.r.bolic problems convergence analysis

Synthesis of a novel centipede-like copolymer of styrene and methyl methacrylate

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2007年第2期50卷 253-257页

作者： LI AiXiang1 & LU ZaiJun2 1 school of Material science and engineering,shandong university of Technology,Zibo 255049,china 2.school of Chemistry and Chemical engineering,shandong university,jinan 250100,china 1. school of Material science and engineering Shandong University of Technology Zibo 255049 China 2. school of Chemistry and Chemical engineering Shandong University Jinan 250100 China

A well-defined,A2B-type,centipede-like copolymer of styrene and methyl methacrylate(pS-pS-pMMA) was synthesized by the combination of living anionic polymerization and atom transfer radical polym-erization(ATrp) . The synthetic ap.r.ach involves the coupling reaction of polystyrene(pS) backbone bearing 1,1-diphenylethene(DpE) pendant groups,produced by ATrp and Wittig reaction,with living polystyryllithium(pSLi) ,and subsequent polymerization of the resulting 1,1-diphenylmethyl anions with methy methacrylate. The centipede-like copolymer was characterized by 1H NMr,Ir,SEC,SLS,and DSC measurements.

关键词： architecture atom transfer radical polymerization centipede-like copolymer coupling reaction living anionic polymerization

Adaptive bidirectional diffusion for image restoration

在线全文

学校读者我要写书评

暂无评论

science china(information sciences) 2010年第12期53卷 2452-2460页

作者： FU ShuJun 1,2 & ZHANG CaiMing 1 1 school of Computer science and Technology, shandong university, jinan 250101, china 2.school of Mathematics, shandong university, jinan 250100, china 1. school of Computer science and Technology Shandong University Jinan 250101 China2. School of Mathematics Shandong University Jinan 250100 China

A large number of applications in image processing and computer vision depend on image quality. In this pap.r. combining the forward diffusion with the backward diffusion by different weights, we present an adaptive bidirectional diffusion method for image denoising and deblurring simultaneously. Further, we introduce a gradient factor into the data fidelity term, which forms a spatially varying constraint and allows a better restoration of image edges and fine details. In order to obtain a stable solution, we develop a numerically stable scheme and give its theoretical analysis. Finally, we show advantages of this method in deblurring edges, denoising and restoring fine details of image comp.r.d with other related methods in exp.r.ments.

关键词： image restoration bidirectional diffusion inverse diffusion anisotropic diffusion stabilizing scheme spatially varying constraint

repetitious-Hot-pressing Technique in Hot-pressing process

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials science & Technology 2003年第5期19卷 486-488页

作者： Shixue SONG, Xing AI, Wei GAO and Jun ZHAO1)school of Mechanical engineering, shandong university, jinan 250061, china2.school of science, jinan university, jinan 250022, china school of Mechanical engineering Shandong University Jinan 250061 China school of science Jinan University Jinan 250022 China

A new pressing method was proposed for hot-pressing process. Exp.r.mental results indicated that the p.r.sity in Al2O3/TiC/ Ni/Mo (hereafter called AI2O3/TiC composite) composite compacts decreases by 6% after adopting this new technique, comp.r.d to traditional hot-pressing technique under the same sintering temp.r.ture. The flexural strength and Vicker hardness increase from 883 Mpa to 980 Mpa and from 16 Gpa to 21.1 Gpa, respectively. A theoretical model was given to analyze the densification mechanism of the composite in the process of repetitious-hot-pressing.

关键词： Hot-pressing sintering repetitious-hot-pressing sintering Composite

Adsorption studies of the removal of anions from aqueous solutions onto an adsorbent prep.r.d from wheat straw

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2010年第6期53卷 1414-1419页

作者： XU Xing,GAO Yue,GAO BaoYu,YUE QinYan & ZHONG QianQian school of Environmental science and engineering,shandong university,jinan 250100,china 1. school of Environmental science and engineering Shandong University Jinan 250100 China

Modified wheat straw (MWS) was prep.r.d by the grafting of epichlorohydrin,triethylamine and ethylenediamine onto *** characteristics of MWS and its adsorption capacity for NO-3,pO34and Cr2O72were *** results indicate that amine groups with positive charge have been introduced into the structure of MWS,and significantly increased its anion adsorption *** functions of MWS dosage,the solution pH,the contact time and temp.r.ture have significant influence on the adsorption process,and the adsorption is well fitted with the Langmuir equation and pseudo second-order *** maximum adsorption capacity of MWS for NO-3,pO34(p) and Cr2O27(Cr) is 53.5,62.4 and 386.2 mg g-1,respectively.

关键词： wheat straw anion adsorption maximum adsorption capacity

Stability for a class of nonlinear time-delay systems via Hamiltonian functional method

在线全文

学校读者我要写书评

暂无评论

science china(information sciences) 2012年第5期55卷 1218-1228页

作者： YANG renMing 1,2 & WANG YuZhen 1 1 school of Control science and engineering,shandong university,jinan 250061,china 2 shandong Jiaotong university,jinan 250023,china 1. school of Control science and engineering Shandong University Jinan 250061 China2. Shandong Jiaotong University Jinan 250023 China

This pap.r.investigates the stability of a class of nonlinear time-delay systems via Hamiltonian functional method,and proposes a number of new results on generalized Hamiltonian realization (GHr) and stability analysis for this class of ***,the concept of GHr of general nonlinear time-delay systems is proposed,and several new GHr methods are ***,based on the new GHr methods obtained,the stability of time-delay systems is investigated,and several delay-dependent sufficient conditions in term of matrix inequalities are derived for the stability analysis by constructing suitable Lyapunov-Krasovskii (L-K) ***,an illustrative example shows that the results obtained in this pap.r.have less conservatism,and work very well in the stability analysis of some nonlinear time-delay Hamiltonian systems.

关键词： nonlinear time-delay systems stability Hamiltonian functional method generalized Hamiltonian realization

H∞ control of a class of nonlinear Hamiltonian descriptor systems

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(information sciences) 2010年第11期53卷 2195-2204页

作者： SUN LiYing1,2 & WANG YuZhen1 1school of Control science and engineering, shandong university, jinan 250061, china 2school of science, university of jinan, jinan 250022, china 1. school of Control science and engineering Shandong University Jinan 250061 China2. School of Science University of Jinan Jinan 250022 China

This pap.r.studies the stabilization and H∞ control of a class of nonlinear Hamiltonian descriptor systems. Firstly, based on the structural characteristic of the nonlinear Hamiltonian descriptor system, an equivalent nonlinear dissipative Hamiltonian differential-algebraic system is obtained by using restricted system equivalent theory. With the dissipative form, the stabilization problem is then discussed for the nonlinear Hamiltonian descriptor systems, and an H∞ controller is designed. Finally, simulations on a nonlinear circuit system are given.

关键词： nonlinear Hamiltonian descriptor systems stabilization H∞ control

Numerical Simulation for FWM power Evaluation in Optical Fiber Transmission Systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

光学学报 2003年第S1期23卷 41-42页

作者： Yan Liu Kang Li Fanmin Kong school of information science and engineering, shandong university, jinan 250100, p. r. china school of information science and engineering Shandong University Jinan 250100 P. R. China

In order to realize reliable and fast simulation of FWM power evaluation, USSD (Uniform Step-Size Distribution) method is modified and its corresponding simulation results of FWM efficiency and computational time are ... 详细信息

关键词： Simulation be FWM Numerical Simulation for FWM power Evaluation in Optical Fiber Transmission Systems for in

A maximum principle for p.r.ially observed optimal control of forward-backward stochastic control systems

在线全文

学校读者我要写书评

暂无评论

science china(information sciences) 2010年第11期53卷 2205-2214页

作者： WU Zhen school of Mathematics, shandong university, jinan 250100, china 1. school of Mathematics Shandong University Jinan 250100 China

This pap.r.studies an optimal control problem for p.r.ially observed forward-backward stochastic control system with a convex control domain and the forward diffusion term containing control variable. A maximum principle is proved for this kind of p.r.ially observable optimal control problems and the corresponding adjoint processes are characterized by the solutions of certain forward-backward stochastic differential equations in finite-dimensional spaces. One p.r.ially observed recursive linear-quadratic (LQ) optimal control example is also given to show the application of the obtained maximum principle. An explicit observable optimal control is obtained in this example.

关键词： maximum principle p.r.ial information adjoint equation backward stochastic differential equation filtering linear-quadratic optimal control