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71.
电机在稳定运行状态下的绕组温度是反映电机性能的重要参数。通常,检测机构依据GB/T1032-2012中规定的方法进行温升试验,至少需要持续3小时,甚至达到6小时。短时间内求取电机稳定温度能够提升检测机构温升检测试验的效率,节约检测机构大量的电力成本和人工成本。同时,根据预测温度能够监测绕组温度,避免绕组的绝缘漆损坏而导致电机烧毁。通过研究均匀纯铜的指数发热规律、创新实时带电测量绕组温度的装置和基于线性逼近方式建立参数估计模型的方法,搭建了在短时间高精度预估电机温度的系统。在对不同功率段电机进行现场温升实验验证中,结果表明系统能够高效准确的预测电机的稳定温度。 相似文献
72.
XU Xiang-yang HAN Jian-min XU Bin-shi LIU Shi-can ZHOU Zhong-rong . Institute of Materials Science Engineering Beijing Jiaotong University Beijing China . Institute of Surface Engineering Chinese Society of Mechanical Engineering Beijing China . Institute ofTribology Southwest Jiaotong University Chengdu China 《材料热处理学报》2004,25(5)
FRETTING is referring to a reciprocating motion withthe small displacement between two components incontact[1].Fretting wear is superficial materialremoval during the fretting.It severely reduces theperformance,efficiency and service lifetime of thecomponents[2],Thermal spraying has been employedto enhance the fretting wear resistance of components,and the fretting wear behavior of the coatings has beenalso explored.However,the experimental results wereoften contradictive and confusing.On … 相似文献
73.
The experiments for rheologic behaviors of semisolid continuous casting billets of A356 alloy in semisolid state had been carried out with a multifunctional rheometer. The results show that the deformation rate increases with loading time, the maximum strain reaches to 120% (which is one time larger than that of traditional mold casting billet) and the strain can be rapidly eliminated to 10% after unloading. Moreover, there is a critic stress for billet deformation even in semisolid state, which is named as critic shear stress. This stress increases with the decreasing of heating time. The theologic behaviors can be expressed by five elements mechanical model (H_2- [N_1|H_2]-[N_2|S]) and can be modified with the increasing of heating time. 相似文献
74.
ZHAO Xuehui ) HUANG Kelong) JIAO Feipeng) LI Zhiaojian) and PENG Xiahui) ) College of Chemistry Chemical Engineering Central South University Changsha China ) Chemistry Department Hunan Technology BOE Science University Zhuzhou China 《稀有金属(英文版)》2006,(2)
1. Introduction Rare earth elements have an important function inlife process. The fluorescence enhancement of lan-thanides in aqueous solutions has therefore becomean area of active study in trace-level estimation oflanthanides using spectrofluorimetry [1]. Its possiblemechanism and application as fluorescence probesin biological systems have also attracted attention inrecent years [2]. Generally, fluorescence enhance-ment can be achieved through ligand sensitization.Various ligands have bee… 相似文献
75.
FAN Jin-juan WANG Quan-sheng ZHANG Wei-fang . Failure Analysis Center of Beijing Institute of Aeronautical Materials Beijing China .Department of material science engineering Beijing Institute of Technology Beijing China 《材料热处理学报》2004,(5)
THERMAL BARRIER COATINGS can holdbackintrusion of high temperature,high heat to increaseapplied temperature and life of substrate metal parts,and have been applied on heat position of rocket,satellite,aero engine and gas engine"31.But thermalstresses are produced during thermal shock due tomismatch of thermal properties between ceramiccoatings and substrate metal,therefore thermal shockproperties of coatings are very poor.Gradient thermalbarrier coatings make materials gradually chang… 相似文献
76.
GAO Bo HAO Sheng-zhi ZOU Jian-xin JIANG Li-min ZHOU Ji-yang'''' DONG Chuang .State Key Lab. of Materials surface Modification by Laser Ion Electron Beams Dalian China .Department of Materials Engineering Dalian University of Technology Dalian China 《材料热处理学报》2004,25(5)
MAGNESIUM ALLOYS exhibit high strength toweight ratio and stiffness and are finding theirapplications in air,automobile and electronic industries.Despite the worldwide growing interests inmagnesium alloys,their inferior wear resistance is aserious impediment.Considering that wear is asurface-related behavior,surface modification canresolve the problem.Recently,intense and pulsed energetic beams areemerging as new and effective methods for surfacemodification.The High Current Pulsed Ele… 相似文献
77.
XU Xiang-yang HAN Jian-min ZHONG Min-lin LIU Wen-jin . Institute of Materials Science Engineering Beijing Jiaotong University Beijing China . Department of Mechanical Engineering Tsinghua University Beijing China 《材料热处理学报》2004,25(5)
NiAl intermetallic alloys are potential high temperaturestructural materials in aeronautical and astronauticalindustries[1].However,the poor ductility andtoughness at room temperature severely restrict theirengineering applications[2,3].It is important todevelop new technology to product intermetallicmaterials for the improvement of the comprehensiveproperties and the workability.Laser powder depositionhas been used to synthesize many new materials.Furthermore,if incorporated with rapid proto… 相似文献
78.
Chemical composition of open-hearth furnace slag isimportant for the metal and casting quality. The chemicalcomponents of slag need to be analyzed precisely andaccurately.For a long time the composition determination of slag ismade chemically, which involves complicated processes,long analytical cycle, high cost and tedious work. A greatmany successful applications of ores analysis by x-rayfluorescence spectrometry (XRF) have been reported[1-4].Powder-fused wafer is a sampling method used in… 相似文献
79.
Shen Yifu Feng Zhongchao Chen Jizhi Liang Yong Institute of Metal Research The Chinese Academy of Sciences Shenyang Department of Materials Science Engineering Nanjing University of Aeronautics an 《中国有色金属学会会刊》1997,(4)
SURFACEMODIFICATIONONSTEELBYRAREEARTHANDLASERTREATMENT①ShenYifu1,2,FengZhongchao1,ChenJizhi1,LiangYong11InstituteofMetalResea... 相似文献
80.
1 INTRODUCTIONAsitwassynthesizedundertheconditionofhightemperatureandhighpressure ,andowingtothecommoncharacteristicsoffinedimensionandhighsurfaceenergyofnanoscaledparticles ,nanodiamond (ND )preparedbydetonationexplosioncaneasilyformstrongaggregates WhenNDpowderwasaddedinaqueousmedia ,obviousaggregationandsedimentationcanbeobserved ,whichimpairsitscharacteristicsasananometerparticle ,andthushindereditsapplication Inthiscase ,stabledispersionofNDinaqueousmediaisofgreatimportance[1 4 ] … 相似文献