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Reflection behaviors of negative permeability metamaterials in X-band

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Progress in Natural Science:Materials International 2006年第3期16卷 324-327页

作者： KANG Lei, ZHAO Qian and ZHAO xiaopeng (Institute of Electrorheological Technology, department of applied physics, Northwestern Polytechnical university, xi’an 710072,{4.) [a]Institute of Flectrorheological Technology Department of Applied Physics Northwestern Polytechnical University Xi'an China

We experimentally investigate the reflection behaviors of negative permeability metamaterials (NPMs) consisting of a periodic array of copper hexagonal split ring resonators (SRRs). Results show that, for the two-dimensional (2-D) NPMs samples, a reflectivity peak with the height of 10 dB appears near the resonance frequency, and the reflectivity is remarkably weak on both sides of the transmission gap; the reflection behaviors of 3-D samples similar to that of the 2-D ones are strongly affected by the lattice constants; the reflection phase increases with the frequency, and an inflexion exists at the resonance frequency of 2-D samples.

关键词： negative permeability metamaterials reflection behaviors.

Surface Nitridation of Molybdenum by Laser-promoted Reaction

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Chinese Journal of Lasers 1997年第2期B6卷 161-168页

作者： WU Jiada WU Changzheng ZHONG xiaoxia SONG Zhoumo LI Fuming(department of physics, Fundan university, Shanghai 2004.3)(Deprtment of applied physics, Northwestern Polytechnical university, xi'an 710072, china) Fudan Univ Shanghai China

Experimental results are reported about the surface nitridation of molyly denum by repeated pulsed laser irradiation on molyboenum foils in pure nitrogen atmosphere. In this laser treatment, the laser irradiation activates nitrogen and melts Mo surface, initating a nitridation reaction in liquid phase. The obtained nitride layers were analyzed and characterized by scanning electron micrography, Auger electron spectroscopy and X -ray diffraction. It is found that the nitride layers contain γ-Mo2N phase and have microstructure much denser than that of the original material. Surface heating and melting and transicnt shock waves induced by laser pulses could account for the microstructure densification of the nitride layers.

关键词： laser-promoted reaction laser heating and melting surface nitridation

All-optical Steerable Directional Coupler Using Kerr Dark Spatial Soliton Waveguides

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Chinese Journal of Lasers 1997年第5期B6卷 452-460页

作者： CHEN xianfeng CHEN Yingli LI Qu (Institute of Optics and Photonics department of applied physics,Shanghai jiaotong {4., Shanghai 200030, china) Shanghai jiaotong Univ Shanghai China

Based on guidemode characters of spatial soliton wavesuides and theory of coupling between two waveguides, it has realized a kind of all-optical steerable directional coupler using spatial soliton waveguides. When input site and corresponding POwer intensity of two spatial solitons change, the output site of the signal through coupling between the two soliton waveguides will change. Some factors such as ratio of soliton and signal wavelength, linear refractive-index of media and coupling length which have influence on the performance of the steerable all-optical directional coupler have been studied.

关键词： spatial soliton waveguides all-optical directional coupler optical communication

The Effect of SRS on Signal Power in Single mode Silica Fiber in DWDM Optical Communication System with Equally Spaced Channels

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Chinese Journal of Lasers 2000年第1期9卷 52-57页

作者： GONG Jiamin 1 FANG Qiang 2 LIU Juan 2 WANG Yongchang 1 ( 1Institute of Modern physics, xi'an jiaotong university, xi'an 71004.,{4. 2department of Telecommunications, xi'an Institute of Posts and Telecommunications, xi'an 710061, C 西安交通大学陕西西安西安邮电学院陕西西安

Assuming that the Raman gain profile of silica fiber is a triangular function, we derive analytic solutions of N channel  steady state forward SRS coupling wave equation with equal (but arbitrary) channel spacing. Considering the SRS cross coupling among N channels,  the analytic solutions are applicable to arbitrary signal light power. The results point out that the sequence m i=p i(z)/p i(0) 〔p i(z) and p i(0) is the power of signal light of i th  channel at transmission length z and 0, respectively. i=1,2,…N〕 maintains a geometric progression with the common ratio q in the transmission process. The common ratio q varies as a exponential function of the effective transmission length, the sum of input light power and the channel spacing, respectively.

关键词： stimulated Raman scattering (SRS) density wavelength division multiplexing fused silica fiber

Exact Controllability of Age-Structured Predator-Prey Populations

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生物数学学报 1997年第3期12卷 208-212页

作者： Zhang Shenghai(department of applied Mathematics xi'an jiaotong university, xi'an {4.,P.R.china) 西安交通大学应用数学系陕西西安

Most predator prey studies have focused on interacting species without age ***,in this paper,we deal with interacting populations with agestructure and obtain global controllability results for a general age-structured predatorprey population systems,using some techniques of nonlinear functional analysis and theories of Semigroup of operators.

关键词： controllability age-structure predator-prey population

LINEAR ACTIVE STRUCTURES AND MODES (Ⅱ) —DISCRETE SYSTEMS AND BEAMS

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applied Mathematics and Mechanics(English Edition) 2004年第8期25卷 854-862页

作者：王永刚龚靖School of Civil Engineering and Mechanics xi'an jiaotong university xi'an 71004. P.R.china {4. of Civil Engineering Northeast china Institute of Electric Power Jilin 132012 P.R.china 张景绘School of Civil Engineering and Mechanics xi'an jiaotong university xi'an 71004. P.R.china School of Civil Engineering and Mechanics Xi'an Jiaotong University Xi'an 710049 P.R.ChinaSchool of Science Chang'an University Xi'an 710064 P.R.China

The basic concepts about the active structures and some attributes of the modes were presented in paper “Liner Active Structures and Modes]( I) ". The characteristics of the active discrete systems and active beams were discussed, especially, the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-storeyed building with sensors and actuators. The concept of the adjoint active structure was extended from the discrete systems to the beams that were the representations of the continuous structures. Two types of beams with different placements of the measuring and actuating systems were discussed in detail. One is the beam with the discrete sensors and actuators, and the other is the beam with distributed sensor and actuator function. The orthogonality conditions were derived with the modal shapes of the active beam and its adjoint active beam. An example shows that the variation of eigenvalues with feedback amplitude for the homo-configuration and non-homo-configuration active structures.

关键词： I) ". The characteristics of the active discrete systems and active beams were discussed especially the stability of the active structures and the orthogonality of the eigenvectors. The notes about modes were portrayed by a model of a seven-s

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GLOBAL SOLUTIONS AND BLOW UP FOR ACTIVATOR INHIBITOR MODEL

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Systems Science and Mathematical Sciences 1998年第3期11卷 238-244页

作者： ZHANG Quande(department of Mathematics, Shaanxi Normal university, xi’an 710062, china)LI Kaitai(Research Center for applied Mathematics,{4., xi’an 71004., china)

This paper deals with the existence and nonexistence of global positive solutions of initial and boundary value problem for the general activator-inhibitor model In this paper, we do not restrict ourselves to the initial data 1/uo, 1/uo ∈L∞(Ω). We prove that there exist glolal solutions if 0 ≤ u0 ≤ u0 and they will blow up in finite time if 0 ≤ v0 ＜ u0 whether u0, v0 are small or large.

关键词： Global solutions blow up of solution activator-inhibitor model

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Tunable left-handed metamaterial based on electrorheological fluids

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Progress in Natural Science:Materials International 2008年第7期18卷 907-911页

作者： Yong Huang, xiaopeng Zhao *, Liansheng Wang, Chunrong Luo Institute of Electrorheological Technology, department of applied physics, Northwestern Polytechnical university, xi’an 710072,{4. Institute of Electrorheological Technology Department of Applied Physics Northwestern Polytechnical University Xi’an 710072 China

A tunable left-handed metamaterial consisting of a periodic array of the left-handed dendritic structure units infiltrated with electro- rheological fluids is demonstrated. Experimental results show that the passband can move from the original 8.50–10.60 GHz to 7.16– 8.39 GHz after electrorheological fluids are infused. When a dc (direct current) electric field of 666 V/mm is applied, the passband moves toward lower frequency of within 7.08–8.30 GHz. This method provides one convenient way to design adaptive metamaterials.

关键词： Left-handed metamaterials Dendritic model Electrorheological fluids Omnidirection

LINEAR ACTIVE STRUCTURES AND MODES (Ⅰ) —BASIC CONCEPTS AND PROPERTIES

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applied Mathematics and Mechanics(English Edition) 2004年第8期25卷 845-853页

作者：张景绘龚靖School of Civil Engineering and Mechanics xi'an jiaotong university xi'an 71004. P.R.china {4. of Civil Engineering Northeast china Institute of Electric Power Jilin 132012 P.R.china 王永刚School of Civil Engineering and Mechanics xi'an jiaotong university xi'an 71004. P.R.china School of Science Chang'an university xi'an 710064.P.R.china School of Civil Engineering and Mechanics Xi'an Jiaotong University Xi'an 710049 P.R.China

Some basic concepts about the active structures were firstly explained, and the main subjects to study in the field of active structure dynamics were synthesized. For the linear active structures, the annotations on the modes were done in detail. The physical meanings of the right and left eigenvectors were explained. The right eigenvectors are the modal shapes and the modal responses of an active structure depend on the left ones. The adjoint structure of an active structure was defined and the reciprocity theorem was interpreted. For two active structures, which are adjoint to each other and with the reciprocal gain-matrices, the right and left eigenvector are reciprocal. The relationship between an active structure and the corresponding passive structure is expressed with the transfer functions, which is employed to resolve the estimation problems.

关键词： active structure vibration control smart structure mode

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