检索结果-南通市图书馆

A class of strong deviation theorems and an approach of Laplace transformation

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第19期43卷 1605-1610页

作者： LIU Wen hebei university of technology, Tianjin 300130, China hebei university of technology Tianjin China

The limit properties of the dependent sequence of absolutely continuous random variables are investigated by using the notion of likelihood ratio, and a class of strong limit theorems, represented by inequalities, i.e. the strong deviation theorems, are obtained. In the proof an approach of applying the Laplace transformation to the investigation of the strong limit theorems is proposed.

关键词： strong deviation theorem strong limit theorem likelihood ratio Laplace transformation.

DYNAMIC RESPONSE OF SHAPE MEMORY ALLOY SYSTEM AND ITS VIBRATION CONTROL

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2000年第4期13卷 312-317页

作者： Wei ZhiSun Dongchang Tan Runhua (School of Mechanical Engineering,hebei university of technology) 河北工业大学天津

A hysteric model is represented to describe the dependence of restoring force on deformation of pseudoelastic *** dynamic response of the system is investigated by means of mathematical *** result shows that this kind of vibration absorbing system can suppress vibration with large amplitude ***,the vibration absorbing system can work in optimum state by adjusting temperature and using piezoelectric sensors and actuators.

关键词： Shape memory alloy Pseudoelasticity Mathematical model Dynamic response Vibration control

NOVEL 6-SPS PARALLEL 3-DIMENSIONAL PLATFORM MANIPULATOR AND ITS FORCE/MOTION TRANSMISSION ANALYSIS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2002年第4期15卷 298-302页

作者： Jin Zhenlin School of Mechanical Engineering, Yanshan university, Qinhuangdao 066004, ChinaGao Feng hebei university of technology School of Mechanical Engineering Yanshan University Qinhuangdao 066004 hebei university of technology

The unique design for a novel 6-SPS parallel 3-dimensional platformmanipulator with an orthogonal configuration is investigated. The layout feature of the parallelmanipulator is described. Its force/motion transmission capability, evaluation criteria arepresented. At the orthogonal configuration, the criteria and the relationships between the criteriaand the link lengths are analyzed, which is important since it can provide designer a piece ofvaluable information about how to choose the linear actuators. From the analysis of the results itis shown that the force/motion transmission capabilities of the parallel manipulator arecharacterized by isotropy at the orthogonal configuration. The manipulator is particularly suitablefor certain applications in 6-DOF micromanipulators and 6-axis force/moment transducers.

关键词： 6-SPS parallel manipulator 3-dimensional platform manipulator isotropy

GENERALIZED SIMULATION MODEL FOR MILLED SURFACE TOPOGRAPHY-APPLICATION TO PERIPHERAL MILLING

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2001年第2期14卷 121-126页

作者： Xu Anping Qu Yunxia Li Weimin School of Mechanical Engineering, hebei university of technology Zhang Dawei Huang Tian Tianjin university 河北工业大学机械学院天津天津大学天津

Based on analyzing various factors influencing milled surface topography, firstly, a generalized model for milled surface topography is proposed. Secondly, using the principles of transformation matrix and vector operation, the trajectory equation of cutting edge relative to workpiece is derived. Then, a three dimensional topography simulation algorithm is constructed through dividing the workpiece into regular grids. Finally, taking the peripheral milling process as an example, the generalized model is simplified, and the corresponding simulation examples are given. The results indicate that it is very efficient for the generalized model to be used to analyze and simulate the peripherally milled surface topography.

关键词： Generalized simulation model Arbitrary contour mill Peripheral milling process Surface topography

Large Eddy Simulation of New Vortex Generator Enhancing Heat Exchange of Solar Energy

在线全文

学校读者我要写书评

暂无评论

湖南大学学报（自然科学版） 2009年第S1期36卷 186-192页

作者： WEN Juan,YANG Li,QI Cheng-ying(Department of Thermal Power Engineering,hebei university of technology,Tianjin 300401,China) Department of Thermal Power Engineering Hebei University of Technology Tianjin 300401 China

This paper put forward a new-type vortex generator enhancing heat exchange of solar air-drier and air-heater on the gas side,and investigated the mechanism of heat transfer enhancement and drag reduction by the influence of vortex generators on the coherent structure of turbulent boundary *** flow and heat transfer characteristics of rectangle channel with bevel-cut half-elliptical column vortex generators were obtained using large eddy simulation(LES)and the hydromechanics software *** instantaneous properties of velocity,temperature and pressure in channel were *** coherent structure of turbulent boundary layer flow was showed,and the characteristic of vortex induced by inclined-cut semi-ellipse vortex generator and its influence on turbulent coherent structure were *** the effect mechanism of turbulent coherent structure on flow field,pressure field and temperature field was *** on the results,the heat transfer coefficient and drag reduction of the new vortex generator with different pitch angles were ***,the coherent effects of the increased wall heat transfer and the decreased skin friction do not satisfy the Reynolds *** turbulent coherent structure can be controlled through the geometry of the vortex generator,so the heat transfer and drag reduction can also be *** we can seek suitable form of vortex generator and structure parameters,in order to achieve the enhanced heat transfer and flow of drag reduction in the solar air-heater and solar air-drier.

关键词： large eddy simulation vortex generator bevel-cut half-elliptical column coherent structure heat transfer enhancement

QUALITY FUNCTION DEPLOYMENT IN BOTTOM-UP PROCESS FOR DESIGN REUSE

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2001年第4期14卷 381-384页

作者： Tan Runhua, Duan Guolin, Liang Yanhong, Yuan Caiyun (School of Mechanical Engineering,hebei university of technology) 河北工业大学天津

To deal with a bottom up process model for design reuses a specific extended house of quality(EHOQ)is proposed Two kinds of supported functions,basic supported functions and new supported functions,are *** processes to determine two kinds of functions are presented A kind of EHOQ matrix for a company is given and its management steps are studied.

关键词： Quality function deployment Bottom up process Design reuse

Three-Dimensional and Cross-sectional Characteristics of Normal Grain Growth Based on Monte Carlo Simulation

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 129-133,139页

作者： Xiaoyan Song Guoquan Liu(Material Science and Engineering School, university of Science and technology Beijing, Beijing 100083, China)(Department of Materials Science and Engineering, hebei university of technology, Tianjin 300130, China) Material Science and Engineering School University of Science and Technology Beijing Beijing 100083 China Departments of Materials Science and Engineering Hebei University of Technology Tianjin 300130 China

An appropriate Monte Carlo method was developed to simulate the three-dimensional normal grain growth more completely. Comparative investigation on the three-dimensional and the cross-sectional characteristics of normal grain growth was done. It was found that the time exponent of grain growth determined from cross-section exhibits the same rule of increasing slowly with time and approaching the theoretical value n = 0.5 of steadygrain growth as the three-dimensional (3-D) system. From change of the number of grains per unit area with timemeasured in cross-section, the state of 3-D normal grain growth may be predicted. The gtain size distribution incross-section is different from that in 3-D system and can not express the evolution characteristic of the 3-D distribution. Furthermore, there exists statistical connection between the topological parameters in cross-section and thosein three-dimensions.

关键词： Monte Carlo simulation normal grain growth three-dimension cross-section characteristics

ARCHITECTURE OF MANUFACTURING EXECUTION SYSTEM IN THE EXTENDED ENTERPRISE

在线全文

学校读者我要写书评

暂无评论

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 university of Science and technology，Shijiazhuang 050054，China Wang Jiahai Zhang Shu Tongji university 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

Fabrication and magnetic properties of Sm_3(Fe,Ti)_(29)N_x/α-Fe dual-phase nanocomposite permanent magnetic material

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2007年第2期50卷 184-189页

作者： CUI ChunXiang, ZHANG Ying, SUN JiBing & WANG Ru School of Materials Science and Engineering, hebei university of technology, Tianjin 300130, China School of Materials Science and Engineering Hebei University of Technology Tianjin China

Sm3(Fe,Ti)29Nx/α-Fe dual-phase nanometer magnetic material was fabricated through rapid solidification, crystallization and nitridation of Sm-Fe (Ti) alloy. The effect of combination of rapid solidification and Ti alloy addition on the phase for- mation and microstructure of the Sm-Fe alloy is investigated in this paper. The mi- crostructure of amorphous phase and dual-phase nano-grain crystals before and after crystallization annealing were observed using a high-resolution transmission electron microscope (HREM). The dual-phase nano-grains after annealing were compacted together with a clear interface with the direct exchange-coupling mechanism. Different annealing processes were used to examine the melt-spun alloy. Comparison of the images of SEM showed that annealing at 750 ℃ for 10 min was most suitable to get homogeneous and nano-grains. No obvious kink was de- tected in the second quadrant of the hysteresis loop like a single hard magnet, and strong exchange coupling was found between hard magnets and soft magnets.

关键词： rapid solidification microstructure Sm3(Fe Ti)29Nx/α-Fe dual phase nanocomposite exchange-coupling