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Decentralized stabilization of large-scale systems with time delays

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Decentralized stabilization of large-scale systems with time...

2011 Chinese Control and Decision Conference（CCDC）

作者： Xiaoshi Xiao,Zhizhong Mao are with the Automation Institute,college of Information science and engineering,Northeastern university,Shenyang,Liaoning 110819,china

Based on Lyapunov-Krasovskii functional method,the problem of decentralized stabilization of large-scale systems with nonlinear time-delayed interconnections and uncertainties is investigated.A decentralized state-feedback controller is proposed to guarantee the asymptotic stability of the resulting closed-loop systems when bound functions of time-delayed interconnections are *** case one can not determine the bound functions of the nonlinear time-delayed interconnections,an adaptive fuzzy controller is put forward to guarantee the stability of the resulting closed-loop large-scale ***,a numerical is provided to demonstrate the efficacy of the proposed control schemes.

关键词： Decentralized stabilization adaptive fuzzy control large-scale systems time delay

Numerical Simulation of Temperature Dependency of Hydrodynamic Behavior in a Fluidization Bed of Coarse Granules

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Numerical Simulation of Temperature Dependency of Hydrodynam...

第七届国际粉体检测与控制学术会议

作者： Li Xiaoguang Xu Delong Fan Haihong college of material science and engineering,Xi’an university of Architecture and technology,china No.13,Yanta Road,Yanta District,Xi’an,710055,china

To explore hydrodynamic behavior of fluidized bed under different temperature,numerical simulation was per- formed in a two-dimensional fluidized bed with 11000 spherical particles of 3ram in *** approach was used to describe the gas flow and the discrete dement method(DEM)based on Lagrangian approach was applied to treat the movement of *** was shown that there is a complex relationship between the minimum fluidizing velocity and temperature,whereas minimum fiuidizing Reynolds number decreases with temperature increasing until it descends more smoothly over the temperature of *** fluidized bed can run more steadily in high temperature than in room tem- perature,because expansion ratio of bed are *** 1700K,majority of granules in emulsion phase retain a quasi- packing state with fluidization number increasing.

关键词： Fluidization Bed Numerical Simulation Coarse Granules Hydrodynamic Behavior

STUDY ON IMPROVING DRYING QUALITY OF SMALL-DIAMETER LUMBERS WITH INTERMITTENT-HEATING METHOD

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STUDY ON IMPROVING DRYING QUALITY OF SMALL-DIAMETER LUMBERS ...

作者： Guo Minghui, Zhao Xiping, Yang Haili Material science and engineering college, Northeast Forestry university, Harbin 150040, china

＜正＞Heating methods affect the drying quality of lumbers. In this study, the small-diameter Birch lumbers were dried with consecution-heats or intermittent-heating, visual drying defects （bow, crook, twist, check along grain and end check） were measured before drying and after drying, and then statistical analysis were performed. It was found that the drying quality of small-diameter Birch lumbers could be improved with intermittent-heating, but the intermittent time should be prolonged. Prolonging intermittent time helped to weaken or even avoid wood distortion and drying checks. It wasn’t helpful in avoiding crook. The drying quality of small-diameter Birch lumbers with all kinds of drying methods reached the second class of the Chinese National Standard. The drying quality reached the first class of the Chinese National Standard with the intermittent-heating in the area of visual wood defects.

关键词： Small-diameter timber Birch lumber Consecution-heats Intermittent-heating Drying quality

Metallographic Characterization of Porosity in A Cast Aluminum Alloy A356-T6

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Metallographic Characterization of Porosity in A Cast Alumin...

2006 Beijing International Conference on Aluminum materials(2006 BICAM)

作者： Guang Ran, Jing'en Zhou State Key Laboratory for Mechanical Behavior of materials, School of materials science and engineering, Xi'an Jiaotong university, Xi'an 710049, china

Microporosity in both HIPped and non-HIPped unmodified aluminum cast alloy A356-T6 was quantified metallographically in terms of its area, area percentage, length, sphericity and perimeter. In the studied materials, the secondary dendrite arm spacing (SDAS) values vary from 82μm to 96μm for both the HIPped and the non-HIPped castings. HIPping process significantly reduces porosity area fraction and pore sizes. The maximum area fraction of porosity and maximum pore area of the non-HIPped specimens are increased with increasing SDAS.

关键词： Cast Al alloy A356 Microporosity Hot isostatic pressing Statistical analysis

The Syntheses and Properties of Poly(L- Lactide)

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Wuhan university Journal of Natural sciences 2002年第4期7卷 473-476页

作者： Chen Lian xi 1, Wang Jun 2, Fu Jie 2, Lei Jia heng 1 1. School of Natural sciences, Wuhan university of technology, Wuhan 430070, Hubei, china 2. School of materials science and engineering, Wuhan university of technology, Wuhan 430070, Hubei, china School of Natural sciences Wuhan University of Technology Wuhan 430070 Hubei China School of materials science and engineering Wuhan University of Technology Wuhan 430070 Hubei China

Poly (L-lactide) was prepared by bulk polymerization ofL-lactide at 140°C in the presence of stannous octoate. The polymer products were characterized by number average molecular weight Mn, weight average molecular weight Mw and molecular weight distribution MWD (M w/M n) respectively. The results showed that stannous octoate was a high effective catalyst, and coordinated insertion mechanism of the reaction was proposed.

关键词： Key words polymerization L lactide molecular weight

维普期刊数据库

Evaluation of Interfacial Adhesion Property for Thin Hard Films with Fuzzy Method

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Journal of Wuhan university of technology(materials science) 2010年第5期25卷 829-831页

作者：朱强 School of Mechanical engineering Zhengzhou University

According to nanoscratch results for the TiN film, an evaluation method for interfacial fracture toughness of thin hard films is presented with fuzzy concepts, which can account for such influential factors in scratch test as surface roughness and material imperfection. Based on configuration changes in scratching curves, the parameters RV and RF are defined as the relative ratios of tip vertical displacement and of friction coefficinet. Fuzzy features of the scratching curves are analyzed carefully. The critical load is deduced from fuzzy logic operations and used to calculate the value of interfacial fracture toughness. With this method, the interfacial fracture toughness of TiN/HSS is evaluated approximately as 4.18 MPam^1/2. Results show that the method is valid and can benefit the interfacial adhesion property investigation for thin hard films.

关键词： interfacial adhesion thin hard films critical load fuzzy evaluation

维普期刊数据库

Some open problems in granular matter mechanics

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Progress in Natural science:materials International 2009年第5期19卷 523-529页

作者： Qicheng Sun a, Guangqian Wanga, Kaiheng Hub a Department of Hydraulic engineering, State Key Laboratory for Hydroscience and engineering, Tsinghua university, Beijing 100084, china b Institute of Mountain Hazards and Environment, Chinese Academy of sciences, Chengdu 610041, china Department of Hydraulic engineering State Key Laboratory for Hydroscience and Engineering Tsinghua University Beijing 100084 China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China

Granular matter is a large assemblage of solid particles, which is fundamentally different from any other type of matters, such as solid and liquid. Most models presented for granular matter are phenomenological and are only suitable for solving engineering problems. Many fundamental mechanical problems remain open. By analyzing characteristics of internal state structure, we propose that granular matter is intrinsically multiscale, i.e. microscale of particle size, mesoscale of force chain, and macroscale of the bulk of granular matter. The correlations among difference scales would be crucial. The mesoscale force chain network is determined by both particle properties and macroscopic boundary conditions. The evolution of the force the chain network contributes to macroscopic mechanical properties of granular matter. In addition, we discuss the drawbacks in simplifying contact forces in the current models, and the difficulties in analyzing the interaction of interstitial fluid in wet granular matter. As an appropriate application of granular matter, debris flow can be studied with granular matter mechanics; meanwhile, debris flow brings more challenges which certainly motivate future studies on granular matter.

关键词： Granular matter Multiscale mechanics Force chain Contact mechanics Debris flow

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中美理工大学研究生教育课程设置研究

外国教育研究 2008年第2期35卷 59-64页

作者：张喜梅陈建东北大学文法学院辽宁沈阳110004 南京理工大学泰州科技学院江苏南京225300

21世纪国家间的竞争是科技和人才的竞争,担负着发展高新科技、培养高级专门人才的研究生教育,特别是理工大学研究生教育,必须不断地通过改革创新来适应社会发展的需要。其中课程设置作为研究生培养中的关键,更值得研究。比较研究我国与... 详细信息

21世纪国家间的竞争是科技和人才的竞争,担负着发展高新科技、培养高级专门人才的研究生教育,特别是理工大学研究生教育,必须不断地通过改革创新来适应社会发展的需要。其中课程设置作为研究生培养中的关键,更值得研究。比较研究我国与美国理工科研究生课程设置存在的问题与成功的经验,可以为改进我国理工科大学研究生课程体系提供些许建议和对策。

关键词：理工大学研究生教育课程设置比较研究

维普期刊数据库

A new algorithm for text segmentation based on stroke filter

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A new algorithm for text segmentation based on stroke filter

2010 Chinese Control and Decision Conference

作者： ZHANG Xiu-li,SHI Zhen-gang college of Information science and engineering,Shenyang Ligong university,Shenyang,110168,china

＜正＞In order to solve segment text accurately and robustly from a complex *** paper propose a new algorithm for text segmentation in images by using a stroke *** this paper,we design a new algorithm for text segmentation by using the stroke ***,we describe the stroke filter briefly based on local region ***, the determination of text color polarity and local region growing procedures are performed based on the response of the stroke ***,the feedback procedure by the recognition score from an optical character recognition（OCR） module is used to improve the performance of text *** proposed algorithm is compared with other *** experimental results demonstrate that the proposed algorithm obtained satisfactory results.

关键词： Text segmentation Complex background Optical character recognition(OCR) Stroke filter