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The effect of the Kerr nonlinearity on the transmission through the nanoslit gold film

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science china(Physics,Mechanics & Astronomy) 2010年第3期53卷 474-480页

作者： XIE SuXia1,2, LI HongJian1,2, XU HaiQing1, ZHOU Xin1, 2, FU ShaoLi1 & WU JinJun1 1 college of Physics science and technology, Central South university, changsha 410083, china 2 college of Materials science and Engineering, Central South university, changsha 410083, china Central South university College of Physics Science and Technology Changsha China (GRID:grid.216417.7) (ISNI:***) Central South university College of Materials Science and Engineering Changsha China (GRID:grid.216417.7) (ISNI:***) Central South university College of Physics Science and Technology Changsha China (GRID:grid.216417.7) (ISNI:***)

This paper has made a theoretical study of enhanced transmission through a gold grating with arrays of subwavelength slits filled with nonlinear Kerr medium. The results of the research are based on rigorous finite-difference time domain calculations. The resonance transmission peaks in the investigated wavelength range are produced as a result of the surface plasmon resonance collaborated with the localized waveguide resonance. The paper also gives a detailed analysis of the influence exerted by various factors: thickness, third-order susceptibility and line refractive index of the nonlinear medium filled in the gold slits arrays and the incident intensity to the transmission. It is found that the small changes of parameters such as medium thickness, third-order susceptibility and line refractive index of the nonlinear medium filled in the gold slits arrays as well as the incident intensity can bring great changes of lateral shift and magnitude variation of the transmission resonance peaks. The report proposes that these phenomena can be applied to designing precise optical switches.

关键词： slit array nonlinear medium localized waveguide resonance surface plasmon resonance Kerr nonlinear effect

Study on BaTiO_3 films prepared by AC power microarc oxidation

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science china(Technological sciences) 2009年第8期52卷 2195-2199页

作者： HUANG WenBo, LI WenFang & HAN Bing college of Material science and Engineering, South china university of technology, Guangzhou 510640, china college of Material science and Engineering South China University of Technology

BaTiO3 films were prepared by microarc oxidation (MAO) with an in-house built alternating current (AC) power supply in Ba(OH)2 solution in this study. The surface morphology, combinability with the substrate and phase composition of the films were investigated by XRD, SEM and TEM. The BaTiO3 films were annealed at a temperature range of 900 to 1200℃ and phase compositions were tested thereafter. The results showed that the BaTiO3 films were mainly composed of the primitive hexagonal phase with relatively small amount of tetragonal and amorphous phases. Moreover, the amount of amorphous phase decreased with the time of annealing. The transformation of BaTiO3 from hexagonal structure to tetragonal stucture became obvious until the annealing temperature reached 1200℃. The film consisted mainly of BaTiO3 tetragonal structure with ferroelectric property. The influence of annealing on surface morphology and mechanism of phase transformation of the films were also discussed.

关键词： microarc oxidation ferroelectric film BaTiO3 annealing phase composition

Algorithm of graph isomorphism with threedimensional DNA graph structures

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Progress in Natural science:Materials International 2005年第2期15卷 86-89页

作者： LIU Guangwu 1,2*, YIN Zhixiang 1,3, XU Jin1 and DONG Yafei1(1. Department of Control science and Engineering, Hua Zhong university of science and technology, Wuhan 430074, china 2. college of transportation, Wuhan university of technology, Wuhan 430063, china 3. Department of Mathematics and Physics, Anhui university of science and technology, Huainan 232001, china) Department of Control science and Engineering Hua Zhong University of Science and Technology Wuhan 430074 China. college of transportation Wuhan University of Technology Wuhan 430063 China. Department of Mathematics and Physics Anhui University of Science and Technology Huainan 232001 China

An algorithm for solving the graph isomorphism problem with 3-D DNA structures is proposed in this paper. The k-armed branched junction molecules are used to code k-degree vertices. Double stranded molecules are used to code edges. Then the molecules are mixed in a tube to be ligated. The result can be detected by gel electrophoresis. The time complexity of the algorithm is O(n2), where n is the number of vertices of the graph.

关键词： DNA computing DNA graph structure graph isomorphism

Focusing transform-based direction-of-arrival method exploiting multi-cycle frequencies

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Progress in Natural science:Materials International 2005年第6期15卷 491-495页

作者： HUANG Zhitao*, JIANG Wenli and ZHOU Yiyu(School of Electronic science and Engineering, National university of Defense technology, changsha 410073, china) School of Electronic science and Engineering National University of Defense Technology Changsha 410073 China

When single cycle frequency is employed, the existing spectral correlation-signal subspace fitting (SC-SSF) algorithms usually contain two disadvantages: those single-cycle estimators cannot reach the best performance; it is inconvenient to be applied in practice since the right cycle frequency has to be selected. Based on the Jacobi-Anger expansion and the idea of focusing transform, a new approach exploiting multi-cycle frequencies of cyclostationary signal is discussed in this paper. Simulation results demonstrate the effectiveness of the new method.

关键词： cyclostationary signal direction-of-arrival multi-cycle frequencies focusing transform.

INTELLIGENT CAR STYLING TECHNIQUE AND SYSTEM BASED ON A NEW AERODYNAMIC-THEORETICAL MODEL

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Chinese Journal of Mechanical Engineering 2002年第2期15卷 110-115页

作者： Huang Xiangdong Xie Chaolin Xie Yuecongcollege of traffic and Communications, South china university of technology,Guangzhou 510640, china college of traffic and Communications South China University of Technology Guangzhou 510640 China ***

Car styling technique based on a new theoretical model of automotiveaerodynamics is introduced, which is proved to be feasible and effective by wind tunnel *** of a multi-module software system from this technique, including modules of knowledgeprocessing, referential styling and ANN aesthetic evaluation etc, capable of assisting car stylingworks in an intelligent way, is also presented and discussed.

关键词： Automotive aerodynamics Artificial intelligence Computer aided styling

Preparation of polystyrene/silica nanocomposites by radical copolymerization of styrene with silica macromonomer

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science china Chemistry 2007年第3期50卷 385-391页

作者： OU BaoLi1,2 & LI DuXin2 1 college of Chemistry and Chemical Engineering, Hunan university of science and technology, Xiangtan 411201, china 2 State Key Laboratory of Powder Metallurgy, Central South university, changsha 410083, china college of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan China State Key Laboratory of Powder Metallurgy Central South University Changsha China

A two-stage process has been developed to generate the silica-based macromonomer through surface-modification of silica with polymerizable vinyl groups. The silica surfaces were treated with excess 2,4-toluene diisocynate (TDI), after which the residual isocyanate groups were converted into polymerizable vinyl groups by reaction with hydroxypropylacrylate (HPA). Thus, polystyrene/silica nanocomposites were prepared by conventional radical copolymerization of styrene with silica macromonomer. The main effecting factors, such as ratios of styrene to the macromonomer, together with polymerization time on the copolymerization were studied in detail. FTIR, DSC and TGA were utilized to characterize the nanocomposites. Experimental results revealed that the silica nanoparticles act as cross-linking points in the polystytene/silica nanocomposites, and the glass transition temperatures of the nanocomposites are higher than that of the corresponding pure polystyrene. The glass transition temperatures of nanocomposites increased with the increasing of silica contents, which were further ascertained by DSC.

关键词： silica nanoparticles surface modification styrene radical copolymerization nanocomposites

The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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science china(Technological sciences) 2006年第2期49卷 238-247页

作者： ZHANG Hai’ou1, QIAN Yingping1,3, WANG Guilan1 & ZHENG Qiguang2 1. School of Material science and technology, Huazhong university of science and technology, Wuhan 430074, china 2. Institute of Laser technology and Engineering, Huazhong university of science and technology, Wuhan 430074, china 3. Mechanical Engineering college, Hubei university of technology, Wuhan 430068, china School of Material science and technology Huazhong University of Science and Technology

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

Preparation of well-defined polystyrene/silica hybrid nanoparticles by ATRP

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science china Chemistry 2008年第1期51卷 51-57页

作者： OU BaoLi1,2 LI DuXin2 1 college of Chemistry and Chemical Engineering,Hunan university of science and technology,Xiangtan 411201, china 2 State Key Laboratory of Powder Metallurgy,Central South university,changsha 410083, china college of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan China State Key Laboratory of Powder Metallurgy Central South University Changsha China

Immobilization of the atom transfer radical polymerization (ATRP) macroinitiators at the silica nanoparticle surfaces was achieved through surface modification with excess toluene-2,4-diisocynate (TDI), after which the residual isocyanate groups were converted into ATRP macroinitiators. Structurally well-defined polystyrene chains were grown from the nanoparticle surfaces to yield individual particles composed of a silica core and a well-defined, densely grafted outer polystyrene by ATRP, which was initiated by the as-synthesized silica-based macroinitiator. FTIR, NMR and gel permeation chro-matography (GPC) were used to characterize the polystyrene/silica hybrid particles.

关键词： silica nanoparticles surface modification atom transfer radical polymerization polystyrene hybrid particle

Structure and Properties of BaFe_(12)O_(19) Coated Fly Ash Cenospheres by Sol-Gel Process

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Journal of Wuhan university of technology(Materials science) 2006年第3期21卷 129-131页

作者：曾爱香 Department of Materials science and technology Changsha University of Science and TechnologyChangsha 410076ChinaState Kay Laboratry of Die and Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

Thin films of barium hexaferrite were prepared on fly ash cenosphere particles by the sol-gel method using Fe（ NO3 ）3 ·9H2O, Ba（ NO3 ）2 and citric acid as raw materials. The prepared films were characterized by differential thermal and thermogravimetric analysis （DTA-TG）, X-ray diffraction analysis （XRD）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDX）, X-ray photoelectron spectroscopy （XPS）, and vibrating sample magnetometry . The magnetic and structural properties of barium hexaferrite coated cenosphere particles were also studied. The experimental results show that even and continual barium hexaferrite coatings were prepared on fly ash cenospheres , and the magnetic conductivity was imparted to these non-conducting oxide ceramic particles. The low density barium hexaferrite coated cenosphere particles may be atilized for manufacturing microwave absorbing materials.

关键词： barium hexaferrite coating fly ash cenosphere particles sol-gel