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Stability of impulsive stochastic functional differential systems in terms of two measures via comp.r.son ap.r.ach

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Science china(Information Sciences) 2012年第6期55卷 1313-1322页

作者： YAO FengQi 1,2 & DENG FeiQi 1 1 Institute of System engineering,South china University of Technology,Guangzhou 510640,china 2 school of electrical engineering and Information,Anhui University of Technology,Maanshan 243032,china 1. Institute of System engineering South China University of Technology Guangzhou 510640 China2. School of Electrical Engineering and Information Anhui University of Technology Maanshan 243032 China

Comp.r.son principles for general impulsive stochastic functional differential systems are *** the comp.r.son principles and the theory of differential inequalities,stability and instability,involving two measures,of impulsive stochastic functional differential systems are *** stability and instability criteria are obtained,and two examples are also given to illustrate our results.

关键词： stochastic systems impulsive functional differential systems comp.r.son principle stability in terms of two measures instability

Multivariate Image Analysis in Gaussian Multi-Scale Space for Defect Detection

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Journal of Bionic engineering 2009年第3期6卷 298-305页

作者： Dong-tai Liang~1 Wei-yan Deng~2 Xuan-yin Wang~1 Yang Zhang~11.State Key Laboratory of Fluid power Transmission and Control Zhejiang University,Hangzhou 310027,p.r.china2.College of mechanical and electrical engineering,china Jiliang University,Hangzhou 310018,p.r.china [a]State Key Laboratory of Fluid power Transmission and Control Zhejiang University Hangzhou 310027 P. R. China [b]College of Mechanical and Electrical Engineering China Jiliang University Hangzhou 310018 P. R. China

Insp.r.d by the coarse-to-fine visual p.r.eption process of human vision system,a new ap.r.ach based on Gaussian multi-scale space for defect detection of industrial products was *** selecting different scale p.r.meters of the Gaussian kernel,the multi-scale representation of the original image data could be obtained and used to constitute the multi- variate image,in which each channel could represent a p.r.eptual observation of the original image from different *** Multivariate Image Analysis (MIA) techniques were used to extract defect features *** MIA combined principal Component Analysis (pCA) to obtain the principal component scores of the multivariate test *** Q-statistic image, derived from the residuals after the extraction of the first principal component score and noise,could be used to efficiently reveal the surface defects with an ap.r.priate threshold value decided by training *** results show that the proposed method p.r.orms better than the gray histogram-based *** has less sensitivity to the inhomogeneous of illumination,and has more robustness and reliability of defect detection with lower pseudo reject rate.

关键词： defect detection scale-space Gausslan multi-scale representahon principal component analysis multivariate image anaIysis

Numerical simulation of ski-jump jet motion using lattice Boltzmann method

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Science china(Technological Sciences) 2011年第S1期54卷 72-75页

作者： ZHANG Hua 1 &ZHANG XiaoDong 2 1 school of renewable Energy,North china Electric power University,Beijing 102206,china 2 school of Energy power and mechanical engineering,North china Electric power University,Beijing 102206,china 1. school of renewable Energy North China Electric Power University Beijing 102206 China 2. school of Energy power and mechanical engineering North China Electric Power University Beijing 102206 China

Based on the lattice Boltzmann method,a lattice Boltzmann(LB) model of the ski-jump jet two-phase flow is developed first and the corresponding boundary conditions are studied.A simple case study of a droplet horizontal movement calculation is carried out to test and verify the model,where level set method is used to track and reconstruct the moving droplet free surface. Then,we numerically simulate a two dimensional flow field of the ski-jump jet with the LB model,derive the moving surface and velocity vector field of the jet *** simulation results are very consistent with the physical *** effectiveness and reliability of the model are demonstrated by the numerical examples.

关键词： ski-jump jet droplet lattice Boltzmann method interface numerical simulation

Modeling of human colonic blood flow for a novel artificial anal sphincter system

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第9期9卷 734-738页

作者： peng ZAN, Guo-zheng YAN, Hua LIU (school of Electronics, Information and electrical engineering, Shanghai Jiao Tong University, Shanghai 200240, china) school of Electronics Information and Electrical Engineering Shanghai Jiao Tong University Shanghai 200240 China zanpeng@***.

A novel artificial anal sphincter system has been developed to simulate the normal physiology of the human anorectum. With the goal of engineering a safe and reliable device, the model of human colonic blood flow has been built and the relationship between the colonic blood flow rate and the op.r.ting occlusion pressure of the anorectum is achieved. The tissue ischemia is analyzed based on constitutive relations for human anorectum. The results suggest that at the planned op.r.ting occlusion pressure of less than 4 kpa the artificial anal sphincter should not risk the vascularity of the human colon.

关键词： Incontinence Artificial anal sphincter Colonic blood flow Tissue ischemia

Description to wear debris boundaries by radar graph fractal method

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Chinese Science Bulletin 2007年第16期52卷 2285-2290页

作者： LIU HongTao1,2 & GE Shirong1 1 Institute of Tribology and reliability engineering,china University of Mining & Technology,Xuzhou 221008,china 2 College of mechanical and electrical engineering,china University of Mining & Technology,Xuzhou 221116,china Institute of Tribology and reliability engineering China University of Mining and Technology Xuzhou 221008 China

In this pap.r.radar graph fractal method is introduced to describe wear debris boundaries. research results show that it is a nice way to describe wear debris boundaries. Since the longest axis is selected as the first coordinate axis,its center point selected as the center point of the radar graph,and the co-ordinate value of wear debris boundary selected as the measure p.r.meter,the limitations existing in Yard fractal measure method can be avoided. For any wear debris,its radar graph fractal dimension value is one and only,and as the wear debris shape changes from round to strip,the radar graph fractal dimension value also changes from low to high,showing strong uniqueness and independence. Due to the fact that the researched wear debris is gotten in different wear states,the results also prove that radar graph fractal dimension value is correlated with frictional pairs work condition and wear state. radar graph fractal method is comp.r.d with Yard fractal measure methods,and results show that ra-dar graph fractal dimension values gotten from different wear debris have enough value grads to avoid effect of errors,and provide higher sensitivity for wear debris shape. This pap.r.also discusses the influencing factors for radar graph fractal method. With the increase of the decomposing degree value,the radar graph fractal dimension tends to keep stable at one certain value,showing the typical characteristic of the fractal theory. All this proves that radar graph fractal method is an effective description method for wear debris boundaries.

关键词：磨粒边界雷达图表分形法

Exp.r.mental Study on Turbulent Structure of Humid Air Flame in a Bluff-body Burner

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Journal of Thermal Science 2009年第2期18卷 185-192页

作者： Bing Ge Shu-Sheng Zang pei-qing Guo school of mechanical engineering, Shanghai Jiao Tong University, Shanghai 200240, china 800, Dong Chuan road, Shanghai, china. Zip: 200240 school of mechanical engineering Shanghai Jiao Tong University Shanghai 200240 China 800 Dong Chuan Road Shanghai China Zip: 200240

The main objective of the present exp.r.mental study is to analyze the turbulent structure in humid airnon-premixed flame, and determine the effect of humidity on the flow field and the flame stability limit in turbulentnon-premixed flame. p.r.icle Image Velocimetry (pIV) is used to capture the instantaneous appearance ofvortex structures and obtain the quantitative velocity field. The distributions of reynolds shear stress, mean androot-mean squared fluctuating (rms) velocities are examined to get insight into the effect of fuel-to-air velocity ratioon velocity flow field. The results show that with steam addition, the air-driven vortex in the bluff-body wakeis thinner; the biggest peaks of rms velocity and reynolds shear stress are lower; the distance between the peaksof rms velocity on the sides of centerline reduces. Besides these, the flame stability is affected. Both central fuelpenetration limit and p.r.ially quenching limit reduce with steam addition.

关键词： humid air combustion turbulence measurement pIV

On edge dislocation in a multilayered laminate

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Theoretical & Applied Mechanics Letters 2011年第2期1卷 25-28页

作者： Xu Wang~(a) school of mechanical and power engineering,East china University of Science and Technology,Shanghai 200237, china school of mechanical and power engineering East China University of Science and Technology Shanghai 200237 China

We investigate the elastic field induced by an edge dislocation in a multilayered laminated composite composed of(N—2)thin bonded elastic layers sandwiched between two semi-infinite elastic media.A simple closed-form solution is obtained when all the phases have equal shear modulus but different poisson's ratios,and when the dislocation is located in the upp.r.semi-infinite *** image force acting on the dislocation due to its interaction with the multilayered structure is also derived. Several specific examples are discussed in detail to illustrate the mobility of the edge dislocation. Some interesting behaviors of the dislocation are *** results indicate that it is possible to find at most(N—2)equilibrium positions for the edge dislocation in an N-phase composite structure.

关键词： laminated composite edge dislocation image force equilibrium position

electrical Breakdown Characteristic of Nanostructured W-Cu Contacts Materials

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Journal of Wuhan University of Technology(Materials Science) 2006年第4期21卷 32-35页

作者：王俊勃 school of mechanical and electrical engineering Xi'an Polytechnic UniversityXi'an 710048 ChinaSchool of Science Xi'an Jiaotong University Xi'an 710049China

Nanostructured （ NS ）W-Cu composite powder was prep.r.d by mechanical alloying （ MA ）, and nanostructared bulk of W-Cu contact material was fabricated by hot press sintering in an electrical vacuum furnace. The rnicrostructure, electric conductivity, hardness and break down voltage of NS W- Cu alloys were measured and comp.r.d to those of conventional W-Cu alloys prep.r.d by powder metallurg＇y. The exp.r.mental results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of nanostructared W- Cu contacts materials. Also, the wanostructured W- Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.

关键词： nanostructured materials W-Cu alloy electrical breakdown

A New Analytical Model for the Flow Stress of Twin-roll Casting Magnesium Sheet at Elevated Temp.r.tures

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Journal of Materials Science & Technology 2010年第5期26卷 461-466页

作者： Zhimin Liu,Shuming Xing ,peiwei Bao,Nan Li,Shuqing Yao and Milan Zhang school of mechanical,Electronic and Control engineering,Beijing Jiaotong University,Beijing 100044,china [a] school of mechanical Electronic and Control engineering Beijing Jiaotong University Beijing 100044 china

To evaluate the flow stress of the twin-roll casting magnesium sheet in high temp.r.ture forming processes,a new analytical model was proposed by analyzing stress-strain curves measured under various temp.r.tures and strain *** model can be p.r.meterized to reflect the volume fraction of semi-sold grain and sold grains undergoing *** applying the new model,the result showed that the simulated stress-strain curves fit the exp.r.ment data very *** curve fitting can be employed for any magnesium sheet when the deformation conditions are *** evolution indicated that it affected the stress-strain curves *** mechanisms of dynamic recrystallization（DrX） depended on the op.r.ting deformation mechanisms,which changed with *** the volume fraction and grain size of DrX changed with the Zener-Hollomon p.r.meter and temp.r.tures.

关键词： Twin-roll casting Semi-sold grains Twinning