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Influence of nanometric CeO2 coating on high temperature oxidation of Cr

Progress in Natural Science:Materials International 2007年第5期17卷 601-606页

作者： Jin Huiming , Zhang Linnan and Liu Xiaojun (Materials Research Center, Department of mechanical engineering, Yangzhou university, Yangzhou 225009, {3. college of Materials Science and engineering, North-East university, Shenyang 110014, {3.) Materials Research Center Department of Mechanical Engineering Yangzhou University Yangzhou 225009 China college of Materials Science and engineering North-East University Shenyang 110014 China

Isothermal and cyclic oxidation behavior of chromium and its superficially applied nanometric CeO2 samples were studied at 900℃in air. Scanning electronic microscopy (SEM), transmission electronic microscopy (TEM) and high resolution electronic microscopy (HREM) were used to examine the morphology and micro-structure of oxide films. It was found that ceria addition greatly improved the anti-oxidation ability of Cr both in isothermal and cyclic oxidizing experiments. Acoustic emission (AE) technique was used in situ to monitor the cracking and spalling of oxide films, and AE signals were analyzed in time-domain and number-domain according to the related oxide fracture model. Laser Raman spectrometer was also used to study the stress status of oxide films formed on Cr with and without ceria. The main reason for the improvement in anti-oxidation of chromium was that ceria greatly reduced the growing speed and grain size of Cr2O3. This fine-grained Cr2O3.oxide film might have better high temperature plasticity and could relieve parts of compressive stress by means of creeping, and maintained the ridge character and relatively low internal stress level. Meanwhile, ceria application reduced the size and the number of interfacial defects, while remarkably enhanced the adhesive property of Cr2O3.oxide scale formed on Cr substrate.

关键词： oxidation stress CeO2 nanoparticle coating chromium.

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Microstructure and formation mechanism of twins of laths of austenite with high nitrogen

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Science china(Technological Sciences) 2007年第6期50卷 755-764页

作者： WU CuiLan1,2 & LUO ChengPing2 1 Center for High Resolution Electron Microscopy, college of Materials Science and engineering, Hunan university, Changsha 410082, {3. 2 college of mechanical engineering, South {3. university of Technology, Guangzhou 510641, {3. Center for High Resolution Electron Microscopy College of Materials Science and Engineering Hunan University Changsha China college of mechanical engineering South China University of Technology Guangzhou China

The microstructure of composite diffusion layer of the nitrided and chromized 0.2% carbon steel is investigated using TEM and EDS. It is found that laths of austenite with high nitrogen (γ N) precipitate from α-ferrite matrix in the deeper zone of the diffusion layer. These γ N laths are all twins, with their {111} twinning planes parallel to the lath axis, thus forming a characteristic "back-to-back" morphology. There are two types of γN lath. The first is a genuinely {111} twin, and γ N and α keep the accurate K-S relationship, and each γ N and α form a sharp and smooth γ N/α inter- face of {335}γN//{341}α, namely habit plane {335}fcc. The second is a pseudo-twin, with micro-twins {111} or faults formed within the two twin components. Localized lattice deformation (relaxation) seems to have occurred at the interfaces of the second type of γ N due to the formation of micro-twins or faults within the twin components. These micro-twins or faults make the orientation relationship (OR) between each of the γN and the α-matrix deviate from the accurate K-S OR, and the OR between two γ N twin components deviate from the genuine {111} twin relation- ship. In addition, the γ N/α interface of the second type of γ N is not as sharp or smooth as that of the first one.

关键词： austenite containing nitrogen, twins, steel 20, nitriding, composite chromizing

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MOTION ANALYSIS AND DESIGN OF ACCUMULATOR FOR HYDRAULIC ROCK DRILL

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中国有色金属学会会刊：英文版 1996年第2期6卷 148-151页

作者： Liu Shixun(college of mechanical and Electrical engineering, Central South {3. of Technology, Changsha 410083. college of mechanical and Electrical engineering Central South University of Technology Changsha 410083 China

ＭＯＴＩＯＮＡＮＡＬＹＳＩＳＡＮＤＤＥＳＩＧＮＯＦＡＣＣＵＭＵＬＡＴＯＲＦＯＲＨＹＤＲＡＵＬＩＣＲＯＣＫＤＲＩＬＬＬｉｕＳｈｉｘｕｎ（ＣｏｌｌｅｇｅｏｆＭｅｃｈａｎｉｃａｌａｎｄＥｌｅｃｔｒｉｃａｌＥｎｇｉｎｅｅｒｉ... 详细信息

ＭＯＴＩＯＮＡＮＡＬＹＳＩＳＡＮＤＤＥＳＩＧＮＯＦＡＣＣＵＭＵＬＡＴＯＲＦＯＲＨＹＤＲＡＵＬＩＣＲＯＣＫＤＲＩＬＬＬｉｕＳｈｉｘｕｎ（ＣｏｌｌｅｇｅｏｆＭｅｃｈａｎｉｃａｌａｎｄＥｌｅｃｔｒｉｃａｌＥｎｇｉｎｅｅｒｉｎｇ，ＣｅｎｔｒａｌＳｏｕｔｈＵｎ...

关键词： hydraulic accumulator diaphragm service life stretching ratio parameter design,motion analvsis

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Cutting Performance and Mechanism of RE Carbide Tools

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Rare Metals 2001年第3期20卷 197-201页

作者： Jianbing Cheng, Yufang Wu, Qixun Yu 1) Department of mechanical engineering, Beijing Technology and Business university, Beijing 10003., {3. 2) college of mechanical engineering and Automation, Beijing Institute of Technology Beijing 100081, {3. 北京工商大学北京 100037 北京理工大学北京 100081

The research of rare earth elements (RE), added into cemented carbide tools, is one of the recent developments of new types of tool materials in china. Systematic experiments about RE carbides YG8R. (K3.), YT14R (P20) and, YW1R (M10) were made to study on the cutting performance in comparison with non-RE carbides YG8, YT14 and YW1. The cutting experiments were as follows: tool life, cutting force, tool-chip friction coefficient and interrupted machining. The action of RE on the carbide materials and the cutting mechanism of the RE carbide tools in the cutting process were verified with the aid of SEM and energy spectrum analysis. Experimental results show that the RE carbide tools have a good overall performance.

关键词： rare earth elements cemented carbide tool cutting performance cutting mechanism

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Control of Multi-Agent Formation with Optimally Persistent Graph

Control of Multi-Agent Formation with Optimally Persistent G...

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第24届中国控制与决策会议

作者： Shikai Shao 1 , Xiaoyuan Luo 1 , Tao Jin 2 , Xinping Guan 1,3.1. Institute of Electrical engineering, yanshan university, qinhuangdao, {3. china 2. college of mechanical engineering, yanshan university, qinhuangdao, {3. china 3. School of Electronic and Electric engineering, Shanghai Jiangtong {13., Shanghai, 200240, china

In this paper, a distributed control law for optimally persistent formation of leader-follower multi-agent systems is presented. According to the characteristic of optimally persistent formation, each follower, except the one which follows the leader, can only communicate with its two precedent neighbors. Based on the state information received from neighbors, a scalable gradient-like control law is designed to control the motion of the formation. Through using this control law, any three agents that are not in a line can achieve a stable triangular persistent formation. Extend this implementation to the whole formation, thus each agent will keep desired distance constraints to its two precedent neighbors. Finally, simulation examples are illustrated to show the efficiency of the proposed control law.

关键词： Persistent formation Multi-agent systems Rigid graph Leader-follower

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ARCHITECTURE OF MANUFACTURING EXECUTION SYSTEM IN THE EXTENDED ENTERPRISE

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Chinese Journal of mechanical engineering 2002年第1期15卷 90-93页

作者： Song Haisheng college of Electronic and mechanical engineering， Hebei {3. of Science and Technology，Shijiazhuang 050054，china Wang Jiahai Zhang Shu Tongji {3. college of Electronic and mechanical engineering Hebei University of Science and Technology Shijiazhuang 050054 Tongji university

The extended enterprise is formed according to the philosophy of dispersednetworked manufacturing. Manufacturing execution system (MES) can close the information gap whichexists between device control system and production information management system. The functions andthe web-based architecture of the MES in the extended enterprise are introduced. Using thecooperating system models of object-oriented and distributed agents and CORBA, all objects keep touniform interface standards and are easily inserted to object request broker. The utilization ofdistributed MES in extended enterprise can adapt fast change of manufacturing environment andresource. It also can improve the independent management capability of manufacturing cell and theenterprise response capability to global economic competition.

关键词： Extended enterprise Manufacturing execution system Dispersed networkedmanufacturing Agent

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Structural ensemble dynamics based closure model for wall-bounded turbulent flow

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Acta Mechanica Sinica 2009年第5期25卷 731-736页

作者： Zhen-Su She Ning Hu You Wu State Key Laboratory for Turbulence and Complex Systems and Dept mechanical and Aerospace engineering,college of engineering, Peking university,100871 Beijing, china State Key Laboratory for Turbulence and Complex Systems and Dept mechanical and Aerospace engineering College of Engineering Peking University Beijing China

Wall-bounded turbulent flow involves the development of multi-scale turbulent eddies, as well as a sharply varying boundary layer. Its theoretical descriptions are yet phenomenological. We present here a new framework called structural ensemble dynamics （SED）, which aims at using systematically all relevant statistical properties of turbulent structures for a quantitative description of ensemble means. A new set of closure equations based on the SED approach for a turbulent channel flow is presented. SED order functions are defined, and numerically determined from data of direct numerical simulations （DNS）. Computational results show that the new closure model reproduces accurately the solution of the original Navier-Stokes simulation, including the mean velocity profile, the kinetic energy of the streamwise velocity component, and every term in the energy budget equation. It is suggested that the SED-based studies of turbulent structure builds a bridge between the studies of physical mechanisms of turbulence and the development of accurate model equations for engineering predictions.

关键词： Turbulence Closure equation Channel flow Structural ensemble dynamics

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Development of Electro-hydraulic Proportional Power Match System for Transporting Girder Vehicle’s Driving

Development of Electro-hydraulic Proportional Power Match Sy...

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第五届流体传动与控制国际会议

作者： Zhao Jingyi Wang Zhiyong Wang Yongchang college of mechanical engineering {3. university qinhuangdao Hebei 066004.china

＜正＞On the basis of analysis of the theory of mechanical-hydraulic power match system,the electro-hydraulic proportional power match system which is suitable for matching TLC900 transporting girder vehicle of the engine is developed according to the driving force-speed curve and parameter,and the control rule and program flow chart about it are put forward [1].Experiments and practice have indicated that the power match system satisfies the capability requirements of the transporting girder vehicle and is of great significance to improve performance and efficiency of the transporting girder vehicle;meanwhile it is useful for other huge driving construction machineries.

关键词： transporting girder vehicle hydraulic system engine power match electro-hydraulic proportional

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INVESTIGATION ON DEPOSITIONS AND HARDNESS CHARACTERISTICS OF a-SiC:H FILMS

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Acta Metallurgica Sinica(English Letters) 1999年第5期12卷 761-764页

作者： X.F.Rong and Z.Y.Qin college of mechanical engineering,Taiyuan {3. of Technology, Taiyuan 03.024, china Taiyuan Univ of Technology Taiyuan China

In this paper, a deposition feature of a SiC:H films deposited by a RF sputtering system and a effect on the hardness of the films with various deposition conditions are investigated, and the effects of the silicon on a C:H are studied. It follows from the results that the properties of hardness can be changed with the depositing conditions. An increase of silane in the gas phase allows to deposit a SiC:H having tetrahedral structure. The sets of deposition conditions by which the different types of a SiC:H films can be deposited are obtained.

关键词： a SiC:H film sputtering hardness

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Load Distribution for Toroidal Drive

Load Distribution for Toroidal Drive

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第十一届IFTOMM世界大会

作者： Lizhong Xu Jinliang Li Wen Yan School of mechanical engineering yanshan {3. qinhuangdao 066004.china

＜正＞Considering eccentric load in the direction of worm axe, the paper gives calculating formulae of the load distribution for the toroidal drive, the calculating results is in good agreement with Peeken test results;The paper also analyzes the regularity of load distribution for the drive. The results are useful in manufacture and design of the drive.

关键词： Toroidal drive Load distribution

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