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Large second-order optical nonlinearities of s-triazine derivatives: View from micro molecules to macro crystals

science china Chemistry 2005年第3期48卷 203-209页

作者： FANG Qi1, LEI Hong2. CUI Yuezhi3, HUANG Zhenli4, XUE Gang1 & YU Wentao1 1. State Key Laboratory of Crystal Materials, shandong university, jinan 250100,{2. 2. school of information science and engineering, shandong university, jinan 250100,{2. 3. Department of Chemical engineering, Light Industry College of shandong, jinan 250100,{2. 4. Key Laboratory of Biomedical Photonics, Ministry of Education, Huazhong university of {12. and Technology, Wuhan 430074,{2. State Key Laboratory of Crystal Materials Shandong University Jinan China school of information {2. and engineering Shandong University Jinan China Department of Chemical engineering Light Industry College of Shandong Jinan China Key Laboratory of Biomedical Photonics Ministry of Education Huazhong University of Science and Technology Wuhan China

Three s-triazine derivatives have been synthesized and their structures been de-termined. These are Compound I: 2.4-dimethyl-6-(p-N,N-dimethylaminostyryl)-s-triazine (abbre-viated to NMe-1), Compound II: 2.4-dimethyl-6-(p-N,N-diethylaminostyryl)-s-triazine (to NEt-1), and Compound III: 2.methyl-4,6-bis(p-N,N-dimethylaminostyryl)-s-triazine (NMe-2.. NMe-1 and NEt-1 molecules belong to the D-π-A type with a one-dimensional charge-transfer character. NMe-1 crystallizes to centrosymmetric P1 space group, while NEt-1 to non-centrosymmetric polar Cc space group with all of the molecular charge-transfer axes taking the same orientation. Under the irradiation of 1064 nm fundamental laser, NEt-1 powder crystals radiate a 2.order harmonic light with an intensity 46.8 times that of urea. The Λ typed NMe-2.molecule, which has a two-dimensional charge-transfer character, crystallizes to polar P2. space group. Its powder crystals exhibit a 2.order harmonic intensity 46.2.times that of urea. The quantum chemical cal-culations and tensor analyses have been carried out to reveal the dependence of the macro 2.order nonlinear optical (NLO) efficiency on the micro 2.order NLO coefficients (β) and on the crystalline packing styles.

关键词： s-triazine derivatives, synthesis, structure, SHG intensities of crystals, βvalues of molecules.

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基于双Haar小波软阈值去噪的阈值选取

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山东大学学报（工学版） 2004年第6期34卷 32-34页

作者：刘真杨大成王欣北京邮电大学电信工程学院北京100876 山东大学信息科学与工程学院山东济南250100

基于双Haar小波提出了一种新的去噪方法 .尽管Donoho对软阈值去噪提出了一个计算阈值的公式 ,但它并不适合双Haar小波 .针对这一问题提出了一种适于双Haar小波变换以及其它非正交小波基的阈值选取方法 ,实验证明此阈值的选取是有效的 .

关键词：软阈值去噪双Haar小波变换阈值选取

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LEAST-SQUARES MIXED FINITE ELEMENT METHODS FOR NONLINEAR PARABOLIC PROBLEMS

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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,{2., 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 parabolic partial differential equation. Convergence analysis; Informatio... 详细信息

关键词： least-squares algorithm mixed finite element nonlinear parabolic problems convergence analysis

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

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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 {2.,shandong university of Technology,Zibo 2.5049,china 2.school of Chemistry and Chemical {2.,shandong university,jinan 250100,china school of Material science and {2. Shandong University of Technology Zibo China school of Chemistry and Chemical engineering Shandong University Jinan China

A well-defined,A2.-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 approach 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

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Adaptive bidirectional diffusion for image restoration

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science china({2. 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,{2., jinan 2.0101, china 2.school of Mathematics,{2., jinan 250100, china school of Computer science and Technology Shandong University school of Mathematics Shandong University

A large number of applications in image processing and computer vision depend on image quality. In this paper, 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 compared with other related methods in experiments.

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

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Repetitious-Hot-Pressing Technique in Hot-Pressing Process

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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,{2., jinan 2.0061, china2.school of science, jinan university, jinan 2.002., 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. Experimental results indicated that the porosity in Al2.3/TiC/ Ni/Mo (hereafter called AI2.3/TiC composite) composite compacts decreases by 6% after adopting this new technique, compared to traditional hot-pressing technique under the same sintering temperature. The flexural strength and Vicker hardness increase from 883 MPa to 980 MPa and from 16 GPa to 2..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

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Adsorption studies of the removal of anions from aqueous solutions onto an adsorbent prepared from wheat straw

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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 {2.,shandong university,jinan 250100,china school of Environmental science and {2. Shandong University Jinan China

Modified wheat straw (MWS) was prepared by the grafting of epichlorohydrin,triethylamine and ethylenediamine onto *** characteristics of MWS and its adsorption capacity for NO-3,PO34and Cr2.72.ere *** 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 temperature 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 Cr2.2.(Cr) is 53.5,62.4 and 386.2.mg g-1,respectively.

关键词： wheat straw anion adsorption maximum adsorption capacity

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A maximum principle for partially observed optimal control of forward-backward stochastic control systems

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science china({2. sciences) 2010年第11期53卷 2205-2214页

作者： WU Zhen school of Mathematics, shandong university,{2., china school of Mathematics Shandong University

This paper studies an optimal control problem for partially 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 partially 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 partially 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 partial information adjoint equation backward stochastic differential equation filtering linear-quadratic optimal control

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Optical waveguides in LiNbO_3 and stoichiometric LiNbO_3 crystals by proton exchange

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science china(Physics,Mechanics & Astronomy) 2008年第10期51卷 1479-1488页

作者： LI ShiLing College of Physics and engineering, Qufu Normal university, Qufu 2.3165,{2. school of Physics and Microelectronics, shandong university, jinan 250100,{2. College of Physics and engineering Qufu Normal University Qufu China school of Physics and Microelectronics Shandong University Jinan China

The formation of optical planar waveguides in LiNbO3 and stoichiometric LiNbO3 crystals by proton exchange was reported. The prism-coupling method was used to characterize the dark-line spectroscopy at the wavelength of 633 and 1539 nm, re-spectively. The mode optical near-field outputs from proton-exchanged LiNbO3 and SLN waveguides at 633 nm were presented. The mode field from stoichiometric LiNbO3 (SLN) waveguide is lighter and more uniform than that from LiNbO3 waveguide, which means the quality of the waveguide in SLN crystal is better than that of the LiNbO3 waveguide. For proton-exchanged LiNbO3 waveguides, the evo-lution of the refractive index profile with annealing was presented. The disorder profiles of Nb atoms in proton-exchanged LiNbO3 waveguides were obtained by Rutherford backscattering/channeling technique. It is shown that the longer the exchange time, the larger the displacement of Nb atoms.

关键词： optical waveguide proton exchange LiNbO3 crystal stoichiometric LiNbO3 crystal

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Intermediate processes and critical phenomena: Theory, method and progress of fractional operators and their applications to modern mechanics

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science china(Physics,Mechanics & Astronomy) 2006年第3期49卷 257-272页

作者： XU Mingyu1 & TAN Wenchang2.1. Institute of Applied Mathematics, school of Math & System science,{2., jinan 250100, china 2. State Key Laboratory of Turbulence and Complex Systems & Department of Mechanics and engineering science, Peking university, Beijing 100871, china nl.gov Institute of Applied Mathematics School of Math & System Science Shandong University Jinan 250100 China

From point of view of physics, especially of mechanics, we briefly introduce fractional operators (with emphasis on fractional calculus and fractional differential equa- tions) used for describing intermediate processes and critical phenomena in physics and mechanics, their progress in theory and methods and their applications to modern me- chanics. Some authors’ researches in this area in recent years are included. Finally, prospects and evaluation for this subject are made.

关键词： fractional operators,intermediate processes,critical phenomena,modern mechanics

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