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A computer simulation of nucleation and growth of thin films

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science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 442-451页

作者： ZHENG Xiaoping1,ZHANG Peifeng2,HE Deyan2,LIU Jun2& MA Jiantai3 1. Key Laboratory of Opto-electronic technology and Intelligent Control, Ministry of Education, Lanzhou Jiaotong university, Lanzhou 730070, china 2. school of Physical science and technology, Lanzhou university, Lanzhou 730000, china 3. school of Chemistry and Chemistry engineering, Lanzhou university, Lanzhou 730000, china Key Laboratory of Opto-electronic technology and Intelligent Control Ministry of Education Lanzhou Jiaotong University Lanzhou China school of Physical science and technology Lanzhou University Lanzhou China school of Chemistry and Chemistry engineering Lanzhou University Lanzhou China

A three-dimensional kinetic Monte Carlo technique has been developed for simulating the nucleation and growth of thin films. This model involves incident atom attachment, surface diffusion of the atoms on the growing surface and atom detachment from the growing surface. It takes some new effects into account, such as a significant improvement in calculation of activation energy for the atom diffusion, which renders the model more reasonable. In addition three optimum temperatures and the consistency of their dependence on deposition rate have been found out; the dependence of the surface roughness and relative density on the deposition rate has been discussed; and the approximation of freezing neighbour atoms and periodic boundary conditions has been applied.

关键词： Monte Carlo, thin film, nucleation, surface roughness, relative density.

UWBWA SAR Imaging Modeling and Its Time-frequency Processing

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UWBWA SAR Imaging Modeling and Its Time-frequency Processing

A Linear Domain System Identification for Small Unmanned Aerial Rotorcraft Based on Adaptive Genetic Algorithm

第七届国际信号处理会议

作者： JIN Tian ZHOU Zhimin CHANG Wenge school of electronic science and engineering national university of defense technology changsha china 410073

In the ultra wide-band, wide-angle synthetic aperture radar (UWBWA SAR) imaging, scatterers often perform the aspect angle and frequency dependent reflectivity character, which usuall

关键词： wide-band wide-angle synthetic aperture radar time-frequency transform

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Journal of Bionic engineering 2010年第2期7卷 142-149页

作者： Xusheng Lei,Yuhu Du school of the Instrumentation science and Opto-electronic engineering,Beihang university,Beijing 100191,P.R.china school of the Instrumentation science and Opto-electronic engineering Beihang University Beijing P. R. China

This paper proposes a new adaptive linear domain system identification method for small unmanned aerial *** the flash memory integrated into the micro guide navigation control module, system records the data sequences of flighttests as inputs (control signals for servos) and outputs (aircraft’s attitude and velocity information).After data preprocessing, thesystem constructs the horizontal and vertical dynamic model for the small unmanned aerial rotorcraft using adaptive *** identified model is verified by a series of simulations and *** between flight data and the one-stepprediction data obtained from the identification model shows that the dynamic model has a good estimation for real unmannedaerial rotorcraft *** on the proposed dynamic model, the small unmanned aerial rotorcraft can perform hovering,turning, and straight flight tasks in real flight tests.

关键词： small unmanned aerial rotorcraft dynamic space model model identification adaptive genetic algorithm

Construction of a multidimensional plane network-on-chip architecture based on the hypercube structure

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Progress in Natural science:Materials International 2009年第5期19卷 635-641页

作者： Chang Wu, Yubai Li, Qicong Peng, Song Chai, Zhongming Yang DSP Lab, school of Communication and Information engineering, university of electronic science and technology of china, Chengdu 610054, china DSP Lab School of Communication and Information Engineering University of Electronic Science and Technology of China Chengdu 610054 China

In current network-on-chip (NOC) studies and in practical applications, the mesh structure is the most widely used and deeply researched structure. However, the hypercube structure is more symmetrical and regular than the mesh or torus structures. This paper compares the network characteristics of these three direct topologies and proposes a method to compress the hypercube into a plane structure. This structure, which has the multidimensional property based on the hypercube, is called the multidimensional plane (MDP) NOC. The compression process is divided into two steps: the transformation of router denotations and the connection of channels. Then, SystemC is used to implement the MDP NOC and it is compared with the mesh and torus NOCs in terms of four aspects of performance, including average latency time, normalization throughput, energy consumption and area cost.

关键词： NOC Hypercube Dimension SystemC Simulation

Bionic Design and Finite Element Analysis of Elbow in Ice Transportation Cooling System

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Journal of Bionic engineering 2010年第3期7卷 301-306页

作者： Dejun Miao~(1,2), Xiuhua Sui~3, Linjing Xiao~3 1. Key Laboratory of Mine Hazard Prevention and Control (Ministry of Education, china), Shandong university of science and technology, Qingdao 266510, P. R. china 2. school of Architecture, Tsinghua university, Beijing 100084, P. R. china 3. College of Mechanical and electronic engineering, Shandong university of science and technology, Qingdao 266510, P. R. china Key Laboratory of Mine Hazard Prevention and Control (Ministry of Education China) Shandong University of Science and Technology Qingdao P. R. China school of Architecture Tsinghua University Beijing P. R. China College of Mechanical and electronic engineering Shandong University of Science and Technology Qingdao P. R. China

With the increase in mining depth, mine heat harm has appeared to be more prominent. The mine heat harm could be resolvedor reduced by ice refrigeration. Thus, ice transportation through pipeline becomes a critical problem; typically flowresistance occurs in the elbow. In the present study, according to the analysis of the surface morphology of fish scale, abiomimetic functional surface structure for the interior wall of elbow is designed. Based on the theory of liquid-solid two phaseflow, a CFD numerical simulation of ice-water mixture flowing through the elbow is carried out using finite element *** experiments of pressure drop and flow resistance for both bionic and common elbows are conducted to test theeffect of the bionic elbow on flow resistance reduction. It is found that with the increase in the ice mass fraction in the ice-watermixture, the effect of bionic elbow on resistance reduction becomes more obvious.

关键词： bionic elbow two phase flow ice transportation flow resistance reduction pressure loss

Analysis of forest backscattering characteristics based on polarization coherence tomography

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science china(Technological sciences) 2010年第S1期53卷 166-175页

作者： LUO HuanMin 1,LI XiaoWen 1,2,CHEN ErXue 3,CHENG Jian 4 & CAO ChunXiang 21 Institute of Geo-Spatial Information science and technology,university of electronic science and technology of china,Chengdu 610054,china 2 State Key Laboratory of Remote Sensing science,Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of sciences and Beijing Normal university,Beijing 100101,china 3Institute of Forest Resources Information Technique of Chinese Academy of Forestry,Beijing 100091,china 4 school of electronic engineering,university of electronic science and technology of china,Chengdu 610054,china Institute of Geo-Spatial Information science and technology University of Electronic Science and Technology of China Chengdu China State Key Laboratory of Remote Sensing science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Institute of Forest Resources Information Technique of Chinese Academy of Forestry Beijing China school of electronic engineering University of Electronic Science and Technology of China Chengdu China

It is difficult to make an inventory of vertical profiles of forest structure parameters in field ***,analysis and understanding of forest backscattering characteristics contribute to estimation and detection of forest vertical structure because of the close relationships between backscattering characteristics and structure *** vertical structure function in the complex interferometric coherence definition,which represents the vertical variation of microwave scattering with the penetration depth at a point in the 2-D radar image and can be used to analyze the forest backscattering characteristics,can be reconstructed from polarization coherence tomography(PCT).Based on PCT,the paper analyzes the forest backscattering characteristics and explores the inherent relationship between the result of PCT and the forest structure parameters from numerical simulation of Random Volume over Ground model(RVoG),Polarimetric SAR interferometry(PolInSAR)simulation of forest scene and PolInSAR data at L-band of the test site ***,the effects of the extinction coefficient and surface-to-volume scattering ratio in RVoG model on vertical backscattering characteristics are analyzed by means of numerical ***,by applying PCT to L-band POLInSAR simulations of forest scene,different variations of vertical backscattering due to different extinction coefficients and the ratios of surface-to-volume scattering resulting from different polarizations,forest types and densities are displayed and *** a concept of relative average backscattering intensity is presented,and the factors which affect its vertical distribution are also *** results show that there is high sensitivity of the vertical distribution of forest relative average backscattering intensity to the polarization,forest type and ***,based on repeat pass DLR E-SAR L-band airborne POLInSAR data,the capability of PCT technology for detection

关键词： backscattering characteristic POLInSAR PCT vertical structure function

A Novel Alternate Polarization Array and Its Filtering Performance

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A Novel Alternate Polarization Array and Its Filtering Perfo...

Crystallization in Zr_(60)Al_(15)Ni_(25) bulk metallic glass subjected to rolling at room temperature

2011 CIE International Conference on Radar(RADAR 2011)

作者： Xu Zhenhai Xiong Ziyuan Xiao Shunping school of electronic science and engineering national university of defense technology changsha 410073 china

Considering the limiting factors of the Polarization Sensitive Array （PSA） in realization, a novel Alternate Polarization Array （APA） has been proposed for the first time. The filtering performance has been presented theoretically and numerically. APA has anti-jamming ability in both space and polarization domains, but quantity of equipment are cut by half compared with PSA. APA possesses of perspective in radar and other fields.

关键词： Polarization Sensitive Array Alternate Polarization Array Filtering Completely Polarized

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science china(Technological sciences) 2010年第1期53卷 278-283页

作者： YAN ZhiJie,YAN Jun,HU Yong & DANG ShuE school of Materials science and engineering,Taiyuan university of science and technology,Taiyuan 030024,china school of Materials science and engineering Taiyuan University of Science and Technology Taiyuan China

The microstructure evolution of Zr60Al15Ni25 bulk metallic glass during rolling at room temperature is investigated by differential scanning calorimetry(DSC),high-resolution transmission electron microscopy(HRTEM) and selected area electronic diffraction(SAED).The HRTEM images show that shear bands are produced in the rolled specimens,indicating the essence of inhomogeneous deformation due to rolling,and that there exist nanocrystals with size of about 5-10 nm in the transition regions between the shear bands and the undeformed matrix in the rolled specimens with deformation degrees of 80% and 95%.Based on the polyhedral structure model and the shear transformation zone(STZ) theory,the influence of viscous flow,free volume,viscosity and the stress situation on the crystallization behaviors in the metallic glass during rolling is discussed.

关键词： metallic glasses plastic deformation nanocrystallization free volume

Design of nonuniform cosine-modulated filter-banks with the perfect-reconstruction property and arbitrary filter lengths

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Progress in Natural science:Materials International 2007年第3期17卷 340-345页

作者： XIE Xuemei (school of electronic engineering, Xidian university, Xi’an 710071, china) school of electronic engineering Xidian University Xi'an 710071 China

In this paper, a method is proposed to construct recombination nonuniform cosine-modulated filter banks (CMFBs) with a perfect-reconstruction property and with arbitrary filter lengths. In this filter bank (FB) structure, certain channels of an original M-channel uniform FB are merged by a set of transmultiplexers (TMUXs), yielding nonuniform outputs, and the length restrictions on the original CMFB and the recombination TMUXs are avoided, allowing them to have arbitrary filter lengths. By imposing certain improved matching conditions on the prototype filters, nonuniform FBs with arbitrary filter lengths and with good properties can be obtained. As a result, the flexibility of selecting modulation types and filter lengths is greatly increased in the design of recombination nonuniform CMFBs. Another benefit due to the flexibility is that the system delay can be reduced.

关键词： recombination nonunlform cosine-modulated filter bank transmultiplexer perfect-reconstruction arbitrary-length.