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Reliability testing and reliability analysis of the over-load protective relay

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第3期8卷 475-480页

作者： ZHAO Jing-ying CHEN Hong-jian LIU Guo-jin ZHANG Yong WU Pin-hua postdoctoral research work station Delixi Group Co. Ltd Wenzhou 325604 China Electrieal Apparatus Institute Hebei University of Technology Tianjin 300130 China

The over-load protective relay is widely used directly affects the safe running of a motor. The reliability for motor protection. The reliability of the over-load protective relay testing and reliability analysis of the over-load protective relay is an important way to improve the reliability of products. In this paper, the reliability test method of the over-load protective relay is studied, and the reliability tests of the typical products are carried out on a reliability tester developed by authors. In terms of the testing results, the reliability analysis is finished. The failure reasons are found and the measures are put forward to improve the reliability of the products.

关键词： Over-load protective relay Protective success analysis ratio Sampling and checking plan Reliability testing Reliability analysis

Study on the influences of ionization region material arrangement on Hall thruster channel discharge characteristics

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Plasma Science and Technology 2018年第2期20卷 47-55页

作者：胡翔段萍宋继磊李文庆陈龙边兴宇 College of Science Dalian Maritime University Transportation Engineering postdoctoral research station Dalian Maritime University

There exists strong interaction between the plasma and channel wall in the Hall thruster,which greatly affects the discharge performance of the *** this paper,a two-dimensional physical model is established based on the actual size of an Aton P70 Hall thruster discharge *** particle-in-cell simulation method is applied to study the influences of segmented low emissive graphite electrode biased with anode voltage on the discharge characteristics of the Hall thruster *** influences of segmented electrode placed at the ionization region on electric potential,ion number density,electron temperature,ionization rate,discharge current and specific impulse are *** results show that,when segmented electrode is placed at the ionization region,the axial length of the acceleration region is shortened,the equipotential lines tend to be vertical with wall at the acceleration region,thus radial velocity of ions is reduced along with the wall *** axial position of the maximal electron temperature moves towards the exit with the expansion of ionization ***,the electron-wall collision frequency and ionization rate also increase,the discharge current decreases and the specific impulse of the Hall thruster is slightly enhanced.

关键词： Hall thruster segmented electrode particle-in-cell wall material

Acoustic localization scheme and accuracy analysis for underwater vertical moving target using seabed stations

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Chinese Journal of Acoustics 2019年第2期38卷 145-166页

作者： ZHANG Xu SUN Ao XIN Jian HAN Xu Unit 91550 of PLA postdoctoral Scientific research work station in Unit 92493 of PLA

To measure the trajectory of an underwater vertical moving target(UVMT) in transient motion with high accuracy and high frame rate,an acoustic localization model using seabed stations with an acoustic beacon was presented.A solution algorithm based on the Gauss-Newton method was derived,which was shown to satisfy the local linear *** analysis of the numerical simulation indicated that the station location,sound velocity,and signal time delay estimation errors were propagated to location parameters through measurement ranges,and the main affecting factors included the station geometry,target relative location,and acoustic *** accuracy was improved using a supplemental surface station coupled with the seabed *** characteristics were indicated by accuracy distribution from the full test sea area.A 14-station array composed of 13 seabed stations and 1 surface station in a test sea of 1 km x 1 km and 60 m in depth demonstrated that the average root mean square errors(RMSEs) in the x,y,and z directions were 0.30,1.47,and0.34 m,respectively,in the vertical range of 35-60 *** work provided a technical approach for UVMT localization,which would be useful for designing related measurement systems.

关键词： Acoustic localization scheme and accuracy analysis for underwater vertical moving target using seabed stations

Perturbation of the Moore–Penrose Metric Generalized Inverse in Reflexive Strictly Convex Banach Spaces

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Acta Mathematica Sinica,English Series 2016年第6期32卷 725-735页

作者： Jian Bing CAO Wan Qin ZHANG postdoctoral research Base He'nan Institute of Science and Technology postdoctoral research station of Physics He'nan Normal University Department of Mathematics He'nan Institute of Science and Technology

Let X, Y be reflexive strictly convex Banach spaces, let T, δT ： X → Y be bounded linear operators with closed range R（T）. Put T= T ＋ δT. In this paper, by using the concept of quasiadditivity and the so called generalized Neumman lemma, we will give some error estimates of the bounds of ｜｜T^M｜｜. By using a relation between the concepts of the reduced minimum module and the gap of two subspaces, some new existence characterization of the Moore-Penrose metric generalized inverse T^M of the perturbed operator T will be also given.

关键词： Metric generalized inverse perturbation reflexive strictly convex Banach space

Electrochemical performance of nano-scale β-Ni(OH)_2 prepared at different transformations of pH value

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Journal of Harbin Institute of Technology(New Series) 2008年第2期15卷 160-163页

作者：赵力张利军韩喜江张翠芬 postdoctoral station of Material Science and Engineering Harbin Institute of Technology postdoctoral work station Jiangsu Shuangdeng Group Co.LtdJiangyan 225526China Dept of Applied Chemistry Harbin Institute of Technology

The influence of transforming pH values on the electrochemical performance of nano-scale Ni （OH）2 was analyzed. The measurement results of XRD indicate that the nano-scale Ni （OH） 2 prepared at different transformations of pH value is β （ Ⅱ ）-phase with different crystal lattice parameters. Cyclic voltammograms （CV） and electrochemical impedance spectroscopy（EIS） measurement results show that transformations of pH value affect the proton diffusion coefficient （D） and charge-transfer resistance （Re,） of the material. The simulation *** experiment shows that the sample prepared at a pH of 10. 1 exhibits the maximum specific capacity （327.8 mAh/g） and higher discharge platform, the discharge performance of electrodes depends on both D and Rct, so the kinetics characteristics that electrodes reaction is controlled by both mass-transfer step and charge- transfer step are put forward.

关键词： nano-material Ni(OH)2 electrochemical transformations of pH value

Fabrication of nano-crystalline W-Ni-Fe pre-alloyed powders by mechanical alloying technique

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中国有色金属学会会刊：英文版 2009年第S3期19卷 711-717页

作者：晏建武刘莹彭阿芳卢全国 Institute of Micro/Nano Actuation and Control Nanchang Institute of Technology postdoctoral workstation of Jiangxihengda Group postdoctoral station of Nanchang University

Nano-crystalline pre-alloyed powders of W-Ni-Fe were fabricated by high energy ball milling mechanical alloying (MA) technique. The change of appearances and the crystallite sizes of powders before and after high energy ball milling were investigated by XRD, TOPAS P software, SEM and EDS. The results show that the nano-crystalline pre-alloyed powders can be fabricated by 5 h high energy ball milling. During the MA process, the diffusion of W, Ni and Fe happens in the process of repeated welding and fracturing. As a result, nano-crystalline supersaturated solid solutions are formed. The crystallite sizes won't be refined after 10 h ball milling. The crystallite sizes of different compositions are almost the same under the same MA condition. Due to the toughening mechanism of rare earth element, the powders of 90W-4Ni-2Fe-3.8Mo-0.2RE alloy are seriously agglomerated after ball milling compared with the other alloys. It can be concluded that the optimal sintering temperature of 90W-4Ni-2Fe-3.8Mo-0.2RE pre-alloyed powders after 15 h mechanical alloying is 1 300-1 350 ℃.

关键词： tungsten based high-density alloy mechanical alloying high energy ball milling nano-crystalline low temperature sintering

Application of fiber Bragg grating sensor network in aluminum reduction tank shell temperature monitoring

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Journal of Central South University 2013年第4期20卷 924-930页

作者：姜明顺隋青美苗飞贾磊彭蓬 School of Control Science and Engineering Shandong University Jinan 250061 China Yanzhou Coal Mining Group postdoctoral work-station Zoucheng 273500 China

A fiber Bragg grating temperature sensor network was designed to implement the real-time health monitoring of the aluminum reduction cell. The heat transfer process was simulated using software ANSYS, and an on-line shell monitoring system was established based on optical sensing technology. According to aluminum reduction cell heat transfer theory, the 2D slice finite element model was developed. The relationship between shell temperature and cell status was discussed. Fiber Bragg grating （FBG） was chosen as the temperature sensor in light of its unique advantages. The accuracy of designed FBG temperature sensors exceeds 2 ~C, and good repeatability was exhibited. An interrogation system with 104 sensors based on VPG （volume phase grating） filter was established. Through the long-term monitoring on running state, the status of the aluminum reduction cell, including security and fatigue life could be acquired and estimated exactly. The obtained results provide the foundation for the production status monitoring and fault diagnosis. Long-term test results show good stability and repeatability which are compatible with electrolysis process.

关键词： aluminum reduction cell fiber Bragg grating numerical simulation shell temperature production status

Preparation of AZ91D magnesium alloy semi-solid billet by new strain induced melt activated method

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中国有色金属学会会刊：英文版 2006年第5期16卷 1080-1085页

作者：姜巨福罗守靖邹经湘 School of Materials Science and Engineering Harbin Institute of Technology postdoctoral Mobile station of Mechanics Harbin Institute of TechnologyHarbin 150001China postdoctoral Mobile station of Mechanics Harbin Institute of Technology

New strain induced melt activated (new SIMA) method for preparing AZ91D magnesium alloy semi-solid billet is introduced by applying equal channel angular extrusion into strain induced step in SIMA method, by which semi-solid billet with fine spheroidal grains and average grain size of 18 μm can be prepared. Furthermore, average grain size of semi-solid billet is reduced with increasing extrusion pass of AZ91D magnesium alloy obtained in ECAE process. By using semi-solid billet prepared by new SIMA, thixoforged magazine plates component with high mechanical properties such as yield strength of 201.4 MPa, ultimate tensile strength of 321.8 MPa and elongation of 15.3%, can be obtained.

关键词：等通道角挤压半固体坯料机械性能镁合金

Two-Level Linear Relaxation Method for Generalized Linear Fractional Programming

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Journal of the Operations research Society of China 2023年第3期11卷 569-594页

作者： Hong-Wei Jiao You-Lin Shang postdoctoral research Base Henan Institute of Science and TechnologyXinxiang453003HenanChina postdoctoral research station of Control Science and Engineering Henan University of Science and TechnologyLuoyang471023HenanChina

This paper presents an efficient algorithm for globally solving a generalized linear fractional programming *** establishing this algorithm,we firstly construct a two-level linear relaxation method,and by utilizing the method,we can convert the initial generalized linear fractional programming problem and its subproblems into a series of linear programming relaxation *** on the branch-and-bound framework and linear programming relaxation problems,a branch-and-bound algorithm is presented for globally solving the generalized linear fractional programming problem,and the computational complexity of the algorithm is ***,numerical experimental results demonstrate the feasibility and efficiency of the proposed algorithm.

关键词： Generalized linear fractional programming Global optimization Two-level linear relaxation method Branch-and-bound