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简介：ThispaperdealswithastudyonSnPbandlead-freesolderedjointreliabilityofPLCCdeviceswithdifferentleadcountsunderthreekindsoftemperaturecycleprofiles,whichisbasedonnon-linearfiniteelementmethod.Byanalyzingthestressofsolderedjoints,itisfoundthatthelargeststressisattheareabetweenthesolderedjointsandtheleads,andanalysisresultsindicatethatthevonMisesstressatthelocationslightlyincreaseswiththeincreaseofleadcounts.ForPLCCwith84leadsthesolderedjointswasmodeledforthreetypicalloading(273-398K,218-398Kand198-398K)inordertostudytheinfluenceofaccelerationfactorsonthereliabilityofsolderedjoints.Andtheestimationofequivalentplasticstrainofthreedifferentlead-freesolderalloys(Sn3.8Ag0.7Cu,Sn3.5AgandSn37Pb)wasalsocarriedout.

简介：Thedigitalizationofarcweldingpowersourcemainlydependsonthedigitalizationofarcweldinginverter,sothatmaincircuitandcontrollingsystemcangivefullplaytoadvantages.DigitalswitchingcontrolmakesmaincircuitdigitalandDSPand/orMCUmakescontrollingsystem,digital.SoIGBTdrivingcircuit,asatieofmaincircuitandcontrollingsystem,shouldalsobegotdigitalized.Thus,adigitaldrivingcircuitbasedonoptocouplerdeviceHCPL-316Jisprovided.Sometestingexperimentsweredone.Afterdrivingtesting,thedrivingcircuitcertificatesthatdrivingwaveformssatisfytherequirementsofarcweldingpowersourceandthedrivingcircuitisreasonablyandsimplydesigned.Andthedrivingcircuithashighcontrollingprecisionandreliability.No-load-voltagetestingandweldingexternalcharacteristictestingprovethatthedrivingcircuitcanbeappliedinarcweldingpowersource.

简介：Weldshapecontrolisafundamentalissueinautomaticwelding.Inthispaper,adoublesidevisualsystemisestablishedforpulsedgasmetalarcwelding(P-GMAW),andbothtopsideandbacksideweldpoolimagescanbecapturedandstoredcontinuouslyinrealtime.Byanalyzingtheweldshaperegulationwiththemoltenmetalvolume,sometopsideweldpoolcharacterizedparameters(WPCPs)areproposedfordeterminingpenetrationinbuttweldingofthinmildsteel.Moreover,someBPnetworkmodelsareestablishedtopredictbacksideweldpoolwidthwithweldingparametersandWPCPsasinputs.

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简介：21世纪，世界已经进入“服务经济时代”。现在的产品与服务可谓“你中有我、我中有你”。服务因素在竞争中已取代产品价格成为竞争的新焦点。毫不夸张地说，现代企业的赢利大多数来自服务，如何在顾客服务中提高顾客满意度、品牌忠诚度，已成为现代企业面临的一项紧迫、重要的课题，而服务理念与服务质量已成为企业竞争力的分水岭。

简介：3月19日上午，2012年北京·埃森焊接与切割展览会《展会综合技术报告》预备会在京如期举行。本次会议由《报告》总策划、中国机械工程学会监事长宋天虎先生主持，来自中国机械工程学会、中国焊接协会焊接设备分会、焊材专委会及切割机具专委会、哈尔滨焊接研究所、国家焊接材料质量监督中心、北京工业大学和《电焊机》杂志社的多位专家学者应邀与会讨论。