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FRACTAL REsEARCH ON CRACKs PROPAGATION OF GAs PIPELINE X52 sTEEL WELDING LINE UNDER HYDROGEN ENVIRONMENT

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Acta Metallurgica sinica(English Letters) 2001年第3期14卷 219-226页

作者： s.H. Dong , Y.M. Lu, Y. Zhang and Q. Wu (Mechanics electronic Department, University of Petroleum, Beijing 102200, China) (Department of Material Physics, University of science and Technology Beijing, Beijing 100083, China) (Yan shan University, Qinhuangd dept. of Mech. electron. Univ. of Pet. Beijing 102200 China

Based on the theory of hydrogen enhanced localized plasticity of the hydrogen induced cracking and the consideration of the effect of the residual stress produced by eliminated stress heat-treatment, a fractal model of hydrogen induced cracking was presented, and the relationships among the effective surface energy (H), fractal dimension D and stress intensity factor of hydrogen induced cracking, KIH, for welding pipeline under hydrogen environment was set up, from which the relationship of D and KIsCC was obtained. The model has been verified experimentally to be correct.

关键词： Crack initiation Electric arc welding Environmental impact Fractals Hydrogen

Intelligent learning technique based-on fuzzy logic for multi-robot path planning

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Journal of Harbin Institute of Technology(New series) 2001年第3期8卷 222-227页

作者：孟庆春殷波熊建设魏天滨王旭柱王汝霖 dept. of electron. Eng. Ocean Univ. of Qingdao Qingdao 266003 China

soccer robot system is a tremendously challenging intelligent system developed to mimic human soccer competition based on the multi discipline research: robotics, intelligent control, computer vision, etc. robot path planning strategy is a very important subject concerning to the performance and intelligence degree of the multi robot system. Therefore, this paper studies the path planning strategy of soccer system by using fuzzy logic. After setting up two fuzziers and two sorts of fuzzy rules for soccer system, fuzzy logic is applied to workspace partition and path revision. The experiment results show that this technique can well enhance the performance and intelligence degree of the system.

关键词： fuzzy logic multi agent system intelligent system robot path planning

BREAKING WAVE FORCEs ON VERTICAL CYLINDERs

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Journal of Hydrodynamics 2002年第4期14卷 110-112页

作者： Ma Ru-jian, Li Gui-xi Department of Mechanical and electronic Engineering, Jinan University, Jinan 250022, China dept. of Mech. and electron. Eng. Jinan Univ. Ji'nan 250022 China

The breaking wave forces on vertical cylinders in shallow waters were studied by means of experimental methods. The results indicate that the breaking wave pressure is distributed exponentially with respect to water depth. An experimental formula was given using the test data. Compared with test data, the calculated breaking wave forces are in good agreement with the test data.

关键词： breaking wave forces pressure distribution of breaking waves experimental study

scattering Characteristics of Liquid Droplets spun Off from Rotating Disk Edge

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Journal of Thermal science 2012年第1期21卷 42-48页

作者： Mizue MUNEKATA Akira NOGUCHI Jun NIsHIYAMA Hiroaki KURIsHIMA Hiroyuki YOsHIKAWA dept. of Mech. system Eng. Kumamoto University 2-39-1 Kurokami Tokyo electron Kyushu Ltd. Fukuhara

scattering characteristics of liquid droplets spun off from a rotating disk edge are experimentally investigated. In the present research, aluminum disks are utilized and ethanol is employed for liquid. scattering phenomena of the droplets are captured by the high-speed digital camera. Frequency distribution of the droplet diameter is evaluated from these images and distributions of horizontal flying velocity and angle of the droplets were measured by PTV. Liquid filaments are stretched outward from the stagnant liquid layer by centrifugal force and skew complicatedly by aerodynamic force. some peaks appear in the distribution of the scattered droplet diameter and they are origi- nated from large terminal droplets and small droplets generated from filamentwise breakup. Most of the scattered droplets fly slightly inside in the tangential direction of the disk edge. The droplets spun off from the thin disk scatter widely compared with that from the thick one.

关键词： Rotating disk scattering droplet Visualization Particle tracking velocimetry

Robot path planning in dynamic environment based on reinforcement learning

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Journal of Harbin Institute of Technology(New series) 2001年第3期8卷 253-255页

作者：庄晓东孟庆春魏天滨王旭柱谭锐李筱菁 dept. of electron. and Eng. Ocean Univ. of Qingdao Qingdao 266003 China

Proposes an adaptive learning method based on reinforcement learning for robot path planning problem, which enables the robot to adaptively learn and perform effective path planning, to avoid the moving obstacles and reach the target. Thereby achieving automatic construction of path planning strategy and making the system adaptive to multi robots system dynamic environments, and concludes from computer simulation experiment that the method is powerful to solve the problem of multi robot path planning, and it is a meaningful try to apply reinforcement learning techniques in multi robot systems to develop the system’s intelligence degree.

关键词： reinforcement learning mobile robot path planning

Influence of Excessive siO_2 or TiO_2 on the Electric Properties of Ba_(0.92)Ca_(0.08)TiO_3 PTCR Ceramics

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Journal of Wuhan University of Technology(Materials science) 2001年第3期16卷 26-29页

作者：曹明贺 dept. of electron. sci. and Technol. Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The dependence of electrical properties of Ba0.92Ca0.08TiO3 PTC ceramics on the sYO2 or TiO2 content was studied. The dependence of room, temperature resistivity on the siO2 content was determined by the variation of the microstructure of Ba0.92Ca0.08TiO3 PTC ceramics . It was shown that a small amount of excessive TiO2 (2mol% ) added could increase the dielectric constant of materials, and it results in a reducing of the potential height (e·) of grain boundary. Thus, samples with particularly low room temperature resistivity were obtained. The relationship of PTC effect with the TiO2 content was also discussed by using the chemistry defect theory . The inferior PTC effect caused by excessive TiO2 may be concerned with the behavior of oxygen vacancies in the grains of ceramics.

关键词： PTCR Ceramics electric properties TiO2 ceramic

Application of neural networks for permanent magnet synchronous motor direct torque control

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Journal of systems Engineering and electronics 2008年第3期19卷 555-561页

作者： Zhang Chunmei Liu Heping Chen shujin Wang Fangjun Information Engineering school Univ. of Science and Technology Beijing Beijing 100083 China Engineering dept. Coll. of Electron Science and Technology Career Beijing 100029 China

Neural networks require a lot of training to understand the model of a plant or a process. Issues such as learning speed, stability, and weight convergence remain as areas of research and comparison of many training algorithms. The application of neural networks to control interior permanent magnet synchronous motor using direct torque control （DTC） is discussed. A neural network is used to emulate the state selector of the DTC. The neural networks used are the back-propagation and radial basis function. To reduce the training patterns and increase the execution speed of the training process, the inputs of switching table are converted to digital signals, i.e., one bit represent the flux error, one bit the torque error, and three bits the region of stator flux. Computer simulations of the motor and neural-network system using the two approaches are presented and compared. Discussions about the back-propagation and radial basis function as the most promising training techniques are presented, giving its advantages and disadvantages. The system using back-propagation and radial basis function networks controller has quick parallel speed and high torque response.

关键词： interior permanent magnet synchronous motor radial basis function neural network torque control,direct torque control.

Natural Mordenite Catalyst Used on the Ammoniation of Methanol

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Chinese Chemical Letters 2001年第6期12卷 527-528页

作者： Li Qiu MAO1, Tong Lai ZHANG1, Chang Gen FENG1, Qing Ze JIAO2, Da Zhen JIANG2 1Department of mechano-electronic Engineering, Beijing Institute of Technology, Beijing 100081 2Department of Chemistry, Jilin University, Changchun 130023 dept. of Mechano-electron. Eng. Beijing Institute of Technology Beijing 100081 China Department of Chemistry Jilin University Changchun 130023 China

The catalytic properties of natural mordenite as acidic catalysts were investigated using the ammoniation of methanol.

关键词： ammoniation of methanol natural mordenite catalytic activity

Photoluminescence of Nanometer siC Powder

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Journal of Materials science & Technology 1997年第4期13卷 333-335页

作者： Yang, XC Han, GR Zhang, XB Du, PY Ding, Zs Zhang, Z ZHEJIANG UNIV DEPT MAT SCI & ENGNHANGZHOU 310027PEOPLES R CHINA CHINEsE ACAD sCI BEIJING ELECTRON MICROSCOPE CTRBEIJING 100080PEOPLES R CHINA

Photoluminescence of nanometer siC powder was found firstly. By TEM, sAED, FTIR and chemical analyses, it is suggested that the quantum confinement effect of nanometer beta-siC be responsible for the blue light and vi... 详细信息

关键词： Nanostructured materials