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PRECIPITATION HARDENING IN B2-ORDERED NiAl BY Ni_(2)AlTi COMPOUND

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Acta Metallurgica Sinica(eng.ish Letters) 2001年第5期14卷 313-318页

作者： W.H. Tian, K. Ohishi and M. Nemoto 1)Department of Materials phys.cs and Chemistry, University of Science and Technology Beijing, Beijing 100083, China 2)Department of Materials Science and eng.neering, Faculty of eng.neering 36, Kyushu University, Fuk Dept. of Mat. phys. and eng. Univ. of Sci. and Technol. Beijing Beijing 100083 China

Microstructural variations and correlated hardness changes in B2-ordered NiAl containing fine precipitation of Ni2AlTi have been investigated by means of transmission electron microscopy (TEM) and hardness tests. The amount of age hardening is not large as compared to the large microstructural variations during aging. TEM observations have revealed that the L21-type Ni2AlTi precipitates keep a lattice coherency with the NiAl matrix at the beginning of aging. By longer periods of aging Ni2AlTi precipitates lose their coherency and change their morphology to the globular ones surrounded by misfit dislocations. The temperature dependence of the yield streng.h of precipitate-containing B2-ordered NiAl was investigated by compression tests over the temperature range of 873-1273 K. The fine precipitation of Ni2AlTi was found to enhance greatly the yield streng.h and the high-temperature streng.h is comparable with that of superalloy Mar-M200.

关键词： Aluminum Hardening Mechanical properties Nickel Precipitation (chemical)

Discovering Overlapping Communities by Clustering Local Link Structures

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Chinese Journal of Electronics 2017年第2期26卷 430-434页

作者： TAO Haicheng.WANG Youquan WU Zhi'ang BU Zhan CAO Jie college of Computer Sci.and eng. Nanjing University of Science and Technology

Recent advances point out that the existing community detection methods commonly face two challeng.s:incorrect base-structures and incorrect membership of *** overcome both problems,a Local link structure(LLS) clustering based method for overlapping community detection is *** extend the similarity of a pair of links to a group of links named LLS,and thus transform mining LLSs as a pattern mining *** prove that LLS with an appropriate threshold can filter weak-ties in the form of bridge and local bridge with its span being larger than 3.A compositive framework is presented for overlapping community detection based on LLS mining and *** experiments on both synthetical and real-world networks demonstrate that our method has advantage over six existing methods on discovering higher quality communities.

关键词： Complex network Overlapping community detection Weak-ties Hypergraph Clustering

Unsteady Correlation between Pressure and Temperature Field on Impinging Plate for Dual Underexpanded Jets

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Journal of Thermal Science 2009年第3期18卷 215-219页

作者： Minoru YAGA Hiroyuki HIGA Shoichi MATSUDA Izuru SENAHA Depts. Mech. Systems eng. Univ. of the Ryukyus Graduate student Faculty of Eng. Univ. of the Ryukyus Okinawa National college of Technology

In this paper, dual underexpanded impinging jets are experimentally studied by measuring unsteady wall staticpressure and temperature fields using high response semiconductor pressure sensors and infrared imaging cam-era(100 captures per sec) with dual converging sonic nozzles. The flow field is also visualized by means of highspeed schlieren system( up to 70000 frame per second) to clarify the unsteady behavior of the jet structures suchas barrel shock wave, and Mach disk. Experiments were performed with a blow down tunnel changing the parameterssuch as the nozzle to plate distance, the distance between the two nozzles, and wind tunnel pressure *** nozzle to plate distance L and the distance between the two nozzles H are non-dimensionalized by the nozzlediameter D covering H/D=1.5, 2.0, and 3, L/D= 2, 3,and 4, and po/pb=1.0 - 5.0, where po and pb are stagnationpressure and back pressure respectively. Although the response of the infrared camera is quite different fromthat of the high speed camera, the unsteady correlation between the pressure and temperature fields is confirmedunder some conditions. Also the high speed schlieren pictures and the wall static pressure fluctuations suggestthat the generation of the Mach disk promote the unsteady behavior of the jets. After the confirmation of the correlation,a simple way to find the severe fluctuating region can be provided according to the two dimensional unsteadytemperature images without a lot of unsteady pressure measurements.

关键词： Shock wave CFD supersonic flow unsteady jet fluctuation

Design of a Proportional-Integral-Derivative Controller for an Automatic Generation Control of Multi-area Power Thermal Systems Using Firefly Algorithm

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IEEE/CAA Journal of Automatica Sinica 2019年第2期6卷 503-515页

作者： K.Jagatheesan B.Anand Sourav Samanta Nilanjan Dey Amira S.Ashour Valentina E.Balas the Department of Electrical & Electronics eng. Mahendra Institute of Eng. & Tech. the Department of Electrical & Electronics eng. Hindusthan College of Eng. & Tech. the Department of Computer Science & eng.neering University Institute of Technology The University of Burdwan the Department of Information Technology Techno India College of Technology the Department of Electronics and Electrical Communications eng.neering Faculty of Engineering Tanta University the Faculty of eng.neering Aurel Vlaicu University of Arad

Essentially, it is significant to supply the consumer with reliable and sufficient power. Since, power quality is measured by the consistency in frequency and power flow between control areas. Thus, in a power system operation and control,automatic generation control(AGC) plays a crucial role. In this paper, multi-area(Five areas: area 1, area 2, area 3, area 4 and area 5) reheat thermal power systems are considered with proportional-integral-derivative(PID) controller as a supplementary controller. Each area in the investigated power system is equipped with appropriate governor unit, turbine with reheater unit, generator and speed regulator unit. The PID controller parameters are optimized by considering nature bio-inspired firefly algorithm(FFA). The experimental results demonstrated the comparison of the proposed system performance(FFA-PID)with optimized PID controller based genetic algorithm(GAPID) and particle swarm optimization(PSO) technique(PSOPID) for the same investigated power system. The results proved the efficiency of employing the integral time absolute error(ITAE) cost function with one percent step load perturbation(1 % SLP) in area 1. The proposed system based FFA achieved the least settling time compared to using the GA or the PSO algorithms, while, it attained good results with respect to the peak overshoot/undershoot. In addition, the FFA performance is improved with the increased number of iterations which outperformed the other optimization algorithms based controller.

关键词： Automatic generation control(AGC) firefly algorithm genetic algorithm(GA) particle swarm optimization(PSO) proportional-integral-derivative(PID) controller

Research on Secure Authentication Mechanism of Grid

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Journal of Donghua University(eng.ish Edition) 2005年第4期22卷 94-97页

作者：张龙军陈克非赵怀勋 Dept. of Computer Sci. and eng. Shanghai Jiaotong University Shanghai 200030 Dept. of Communicate eng. Eng. College of Armed Police Force Xi'an 710086

Based on the analysis on the security mechanism of grid, this paper discusses the advantages of latest techniques of grid security, and presents a secure authentication scheme of grid based on elliptic curve cryptosys... 详细信息

关键词： Grid GT3 ECC.

Nonlinear Mixed-Effects Models for Repairable Systems Reliability

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Journal of Shanghai Jiaotong university(Science) 2007年第2期12卷 283-288页

作者：谭芙蓉江志斌郭位裴锡柱 School of Mechanical eng. Shanghai Jiaotong Univ. college of eng. the Univ.of TennesseeKnoxvilleTN 37996USA Dept.of Industrial eng. Hanyang Univ.SeoulKorea

Mixed-effects models,also called random-effects models,are a regression type of analysis which enables the analyst to not only describe the trend over time within each subject,but also to describe the variation among different *** mixed-effects models provide a powerful and flexible tool for handling the unbalanced count *** this paper,nonlinear mixed-effects models are used to analyze the failure data from a repairable system with multiple *** using this type of models,statistical inferences about the population and all copies can be made when accounting for copy-to-copy *** of fitting nonlinear mixed-effects models to nine failure-data sets show that the nonlinear mixed-effects models provide a useful tool for analyzing the failure data from multi-copy repairable systems.

关键词： repairable systems reliability analysis nonlinear mixed-effects models power law process maximum likelihood estimation

An Expert System in FRP Composite Material Design

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Journal of Materials Science & Technology 2001年第5期17卷 556-560页

作者： Qingfen LI, Zhaoxia CUI and Weimin WANG college of Mechanical & Electrical eng.neering, Harbin eng.neering University, Harbin 150001, China Jianhua GAO Department of Mechanical eng.neering, Shanghai Jiao Tong University, Shanghai 200030, China Coll. of Mech. and Electron. eng. Harbin Eng. Univ. Harbin 150001 China

An expert system prototype for fibre-reinforced plastic matrix (FRP) composite material design, ESFRP, has been developed. The system consists of seven main functional parts: a general inference eng.ne, a set of knowledge bases, a material properties algorithm base, an explanation eng.ne, various data bases, several function models and the user interface. The ESFRP can simulate human experts to make design scheme for fibre-reinforced plastics design, FRP layered plates design and FRP typical eng.neering components design. It can also predict the material properties and make streng.h analysis according to the micro and macro mechanics of composite materials. A satisfied result can be gained through the reiterative design.

关键词： An Expert System in FRP Composite Material Design FRP

THE MAPPING RELATION AMONG SOLUTION OF SOME NONLINEAR EQUATIONS

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Acta Mathematica Scientia 1989年第2期9卷 131-141页

作者：倪光炯楼森岳 Inst. of Modern phys. Fudan Univ. Shanghai China Dept. of phys. Ningbo Normal College Ningbo China

Among the solutions of three kinds of nonlinear equations in one dimensional systems, cubic nonlinear Klein-Gordon (including Φ~4), Sine-Gordon and double Sine-Gordon, some mapping relations exist. When a solution of... 详细信息

关键词： DSG THE MAPPING RELATION AMONG SOLUTION OF SOME NONLINEAR EQUATIONS

Convective Boiling of Near-Azeotropic Refrigerant R410A in the Horizontal Micro-fin Tube

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Journal of Shanghai Jiaotong university(Science) 2007年第1期12卷 73-75,80页

作者：段雪涛马虎根邬志敏王芳 college of Power eng. Univ. of Shanghai for Science and Technology

Using near-azeotropic refrigerant R410A as the working fluid, the experimental studies on the horizontal micro-fin tubes were conducted. Several factors affecting heat transfer coefficients were analyzed, and the characteristics of flow boiling of the refrigerant in the horizontal micro-fin tubes were discussed. The local heat transfer coefficients increase with mass flux, heat flux and quality. And the heat transfer enhancement factor of those testing tubes is about 1.6 to 2.2.

关键词： horizontal micro-fin tube near-azeotropic refrigerant convective evaporation heat transfer