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控制策略与载波比对电机损耗与温度场的研究

电机与控制学报 2016年第6期20卷 17-25页

作者：李伟力李金阳姜少义李琳北京交通大学电气工程学院北京100044 哈尔滨工业大学电气工程及自动化学院黑龙江哈尔滨150001

以一台2 000 r/min、12.5 k W的永磁伺服电机为研究对象,根据电机实际结构与控制参数建立两种控制策略的永磁伺服电机二维瞬态有限元场路耦合模型。然后对采用正弦波控制策略的二维瞬态有限元场路耦合模型进行计算,通过与实测结果对比,... 详细信息

以一台2 000 r/min、12.5 k W的永磁伺服电机为研究对象,根据电机实际结构与控制参数建立两种控制策略的永磁伺服电机二维瞬态有限元场路耦合模型。然后对采用正弦波控制策略的二维瞬态有限元场路耦合模型进行计算,通过与实测结果对比,验证计算方法的准确性。在此基础上,详细研究采用方波控制和正弦波控制时载波比对电机定子铁耗与转子护套涡流损耗的影响。最后,根据稳态传热理论,建立永磁伺服电机三维全域温度场有限元模型,分别对采用上述两种控制方式不同载波比情况下电机的温度场进行了计算,研究了电机各部件的温度变化规律。研究内容为永磁伺服电机控制方式及控制参数的选择提供参考依据。

关键词：永磁伺服电机控制方式场路耦合涡流损耗温度场

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买方势力条件下的供应链扭曲与协调问题研究

系统工程学报 2017年第4期32卷 522-534页

作者：李凯李伟东北大学工商管理学院辽宁沈阳110169

针对买方势力不断增强的现象,在具有创新和促销特征的供应链中,构建了不同买方势力分布的决策模型,考察了不同势力结构下企业的最优创新决策、促销决策和供应链总利润,分析了买方势力变化对供应链扭曲程度的影响.研究结果表明:在不同买... 详细信息

针对买方势力不断增强的现象,在具有创新和促销特征的供应链中,构建了不同买方势力分布的决策模型,考察了不同势力结构下企业的最优创新决策、促销决策和供应链总利润,分析了买方势力变化对供应链扭曲程度的影响.研究结果表明:在不同买方势力条件下,企业创新决策、促销决策以及供应链总利润都会发生扭曲,且扭曲程度主要取决于价格敏感系数、创新成本系数以及促销成本系数的取值.此基础之上,论文还探讨了买方势力背景下的供应链协调机制,设计了基于买方势力的供应链协调契约,消除了创新决策和促销决策的扭曲,使供应链达到了协调.

关键词：买方势力供应链扭曲供应链协调创新决策促销决策

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WT-ANFIS在孤岛检测中的应用研究

电机与控制学报 2016年第1期20卷 35-42页

作者：周皓李维刚童朝南李伟力茆美琴北京科技大学自动化学院北京100083 北京交通大学电气工程学院北京100044 武汉科技大学信息科学与工程学院湖北武汉430081 合肥工业大学教育部光伏系统工程中心安徽合肥230009

针对传统被动式孤岛检测法存在检测时间长、盲区大,而主动式孤岛检测法影响电能质量的缺点,提出一种新的基于模糊神经网络与小波变换的孤岛检测方法。该方法首先采集逆变器输出的电流信号和公共耦合点处的电压信号,再将该电流信号和电... 详细信息

针对传统被动式孤岛检测法存在检测时间长、盲区大,而主动式孤岛检测法影响电能质量的缺点,提出一种新的基于模糊神经网络与小波变换的孤岛检测方法。该方法首先采集逆变器输出的电流信号和公共耦合点处的电压信号,再将该电流信号和电压信号分别进行小波变换,然后通过对各尺度上的细节信号进行算法处理来获取适合于孤岛检测的特征向量,最后该特征向量通过模糊神经网络进行模式识别来判断系统是否发生孤岛现象。仿真与实验结果表明,该方法在并网逆变器功率与本地负载功率匹配及失配的多种条件下均能有效识别,具有检测速度快,盲区小,对电能质量无影响等优点,并且适合于单相、三相光伏并网系统。

关键词：孤岛检测小波变换模糊神经网络细节信号特征向量

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次级对直线感应电动机性能的影响

电机与控制学报 2008年第1期12卷 47-51页

作者：彭威李伟力程树康李红涛中国舰船研究设计中心湖北武汉430064 哈尔滨理工大学电气与电子工程学院黑龙江哈尔滨150040 哈尔滨工业大学电气工程及自动化学院黑龙江哈尔滨150001

为了研究直线感应电动机次级材料和厚度对电机性能和气隙磁密的影响,采用有限元方法,建立了电机的电磁场计算模型,研究电机的起动及运行过程。在数值计算的基础上得到电机的磁场分布,对气隙磁密进行谐波分析,得到了随着次级板厚度减小,... 详细信息

为了研究直线感应电动机次级材料和厚度对电机性能和气隙磁密的影响,采用有限元方法,建立了电机的电磁场计算模型,研究电机的起动及运行过程。在数值计算的基础上得到电机的磁场分布,对气隙磁密进行谐波分析,得到了随着次级板厚度减小,气隙磁场增强,谐波含量较小的变化规律,并在电磁气隙不变的情况下,分析次级厚度及材料变化时对电机推力的影响,即随着次级板厚度及次级电导率减小,电机起动推力减小。实验结果验证了该电机计算模型的正确性。

关键词：直线感应电动机气隙磁密起动推力有限元法

Nerve plane-sparing radical hysterectomy： a simplified technique of nerve-sparing radical hysterectomy for invasive cervical cancer

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Chinese Medical Journal 2011年第12期124卷 1807-1812页

作者： li Bin li wei SUN Yang-chun ZHANG Rong ZHANG Gong-yi YU Gao-zhi WU ling-ying Department of Gynecologic Oncology Cancer Hospital PekingUnion Medical College Chinese Academy of Medical SciencesBeijing 100021 China

Background In order to simplify the complicated procedure of nerve-sparing radical hysterectomy, a novel technique characterized by integral preservation of the autonomic nerve plane has been employed for invasive cervical cancer. The objective of this study was to introduce the nerve plane-sparing radical hysterectomy technique and compare its efficacy and safety with that of nerve-sparing radical hysterectomy. Methods From September 2006 to August 2010, 73 consecutive patients with International Federation of Gynecology and Obstetrics stage IB to IIA cervical cancer underwent radical hysterectomy with two different nerve-sparing approaches. Nerve-sparing radical hysterectomy was performed for the first 16 patients （nerve-sparing radical hysterectomy group）. The detailed autenomic nerve structures were identified and separated by meticulous dissection during this procedure. After January 2008, the nerve plane-sparing radical hysterectomy procedure was developed and performed for the next 57 patients （nerve plane-sparing radical hysterectomy group）. During this modified procedure, the nerve plane （meso-ureter and its extens;ion） containing most of the autonomic nerve structures was integrally preserved. The patients＇ clinicopathologic characteristics, surgical parameters, and outcomes of postoperative bladder function were compared between the two groups. Results There were no significant differences between the nerve plane-sparing radical hysterectomy and nerve-sparing radical hysterectomy groups regarding age, International Federation of Gynecology and Obstetrics stage, pathological type, preoperative treatment, or need for intraoperative blood transfusion. The nerve plane-sparing radical hysterectomy group had a higher body mass index than that of the nerve-sparing radical hysterectomy group （P=0.028）. The mean surgical duration in the nerve plane-sparing radical hysterectomy and nerve-sparing radical hysterectomy groups were （262_＋46） minutes and （341＋36） minute

关键词： cervical cancer radical hysterectomy pelvic autonomic nerves pelvic nerve plane bladder function

HL-2A Tokamak Experiment Data System

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Southwestern Institute of Physics Annual Report

Southwestern Institute of Physics Annual Report 2005年第1期 77-78页

作者： CHEN liaoyuan LUO Cuiwen liYongge PAN li PAN wei ZHAO li li Guohui

HL-2A tokamak experiment data system （ HL-2A EDS ） consists of an experiment network, various of dada acquiring sub-systems, a great deal of realtime data processing applications, a display system, a lot of interacting data analyzing workstations, a data storage system, a management platform, and a high performance computer. The system was built start in 2002, and has been modified greatly since then.

关键词： Data system Dada acquiring Data processing

SCGM(1,m)_c model with time-lag and its application in deformation analysis

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Journal of Central South University of Technology 2001年第1期8卷 40-44页

作者： li Zhi wei 1, li Tao 1,ZHU Jian jun 1,WANG Ren qian 2 (1.College of Resources, Environment and Civil Engineering, Central South University, Changsha 410083, China 2.Department of Civil Engineering, Huaqiao University, Quanzhou 350029, China) College of Resources Environment and Civil Engineering Central South University Changsha China Department of Civil Engineering Huaqiao University Quanzhou China

Originated in the early 1990s, SCGM(1, m ) c model has enjoyed widespread application in the fields of urban planning, society economy prediction and modal control in recent years. However, none of these applications have taken account of time lag effects in the modeling process. Aiming at overcoming the defect, the authors introduced time lag items into SCGM(1, m ) c model and developed a SCGM(1, m ) c model with time lag, then discusses in detail some principal problems in the model, such as parameters estimation, model verifying, model prediction, etc. The model was used on a real slope monitoring project and compared with the conventional SCGM(1, m ) c model. The results show an improvement of average models precision from 1.321 to 0.238 and total average of relative prediction errors from 12.41% to 7.98% when the modeling data length ranges from 29 to 48 in the slope monitoring case.

关键词： grey system SCGM(1,m)c time-lag deformation analysis

GC-MS STUDY ON DIURETICS IN URINE Ⅰ.BETECTION METHOD USING METHYLATION

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Chinese Chemical Letters 1990年第3期1卷 225-228页

作者： Ya wei li Jun li Shao Tang ZHU Tong Hui ZHOU Institute of Materia Medica,Chinese Academy of Medical Sciences Beijing 100050,China

A reliable and sensitive method is developed for the detection of common diuretics in human urine. diuretics along with probenecid are methylated and subjected to GC-MS *** chromatographic and mass spectrometric data are obtained in selected ion monitoring and full scanning *** average detection limit is 0.1-1.0 ag/mi *** method is suitable to large-scale and routine screening or confirmation of diuretics in doping control.

关键词： OC GC-MS STUDY ON DIURETICS IN URINE BETECTION METHOD USING METHYLATION MS

NUMERICAL SIMULATION AND EXPERIMENTAL INVESTIGATION OF THE GUIDE-VANE FLOW AND THE INFLUENCE FROM THE LEAKAGE FLOW

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Journal of Hydrodynamics 2003年第1期15卷 103-110页

作者： liaowei-li liJian-zhong InstituteofwaterResourcesandHydroelectricEngineering Xi＇anUniversityofTechnologyXi＇an710048China InstituteofwaterResourcesandHydroelectricEngineering Xi＇anUniversityofTechnologyXi＇an710048China

This paper presents numerical and experimental results of the flow in the tipclearance region of the guide vane row in hydraulic turbine. The 3-D Navier-Stokes equations wereemployed to model the flow in end clearance region of guide vane cascade, the Reynolds stressdifferential model was used for turbulence closure, and the body-fitted curvilinear coordinates andthe SIMPLE! algorithm were adopted. The governing equations were discretized with the non-staggeredgrids by means of the finite volume method. Detailed comparison of hydrodynamical characteristics ofguide vane in hydraulic turbine with or without tip gap was made. Special attention was paid to theinfluence of leakage flow on the main flow and to the movement of tip leakage flow in the end guidevane. The position and strength of the roll-vortex on the sides of guide vane in were *** numerical solutions agree with the experimental results obtained by particle image *** results help to clarify the loss, wear and cavi-tation erosion between the guide vane andrings, especially for those used in the Yellow River which has a high sediment content.

关键词： leakage flow guide vane reynolds stress differential model