简介：TheevaluationofcreepdamagesofCr-Mo-Vsteelusedinthegasturbineofpowerplanthasbeencarriedoutusingtheline-focus-beam(LFB)acousticmicroscopy.Thevelocityofleakysurfaceacousticwave(LSAW)propagatednearthespecimensurfacewasusedforthequantitativeevaluations,whichwasmeasuredbyLFBacousticmicroscopyusingthev(z)curveanalysismethod.IthasbeenshownthatwiththeincreaseofcreepdamagefractionofmetalmaterialtheLSAWvelocitydecreasesobviously,whichsuggeststhepossibilityofnondestructiveandquantitativeevaluationsofcreeddamagesinmetalmaterialsbyacousticmicroscopy.

简介：Simpleandefficientsurfaceacousticwave(SAW)two-portresonatorswithlowinsertionlossandhighQ-valuesonST-Xquartzsubstrateusingacorrosion-proofA1/Au-stripeelectrodestructurearedevelopedforgassensing.Itwascomposedoftwoshortedgratingreflectorsandadjacentintedigitaltransducers(IDT),andanactivemetalfilminthecavitybetweentheIDTsforthesensitivefilmcoating.Thedevicesareexpectedtoprovidegoodprotectiontowardsmetalelectrodeforgassensorsapplicationinchemicallyreactiveenvironments.Excellentdeviceperformanceaslowinsertionloss,highQfactorandsingle-modeareachievedbycarefullyselectingthemetallicelectrodethickness,cavitylengthandacousticaperture.Priortofabrication,thecouplingofmodes(COM)modelwasperformedfordevicesimulationtodeterminetheoptimaldesignparameters.Thefabricatedsingle-modeSAWresonatoratoperationfrequencyof300MHzrangeexhibitsmatchedinsertionlossof~6.5dBandloadedQfactorinthe3000range.Usingthefabricatedresonatorasthefeedbackelement,adualresonator-oscillatorwithexcellentfrequencystability(0.1ppm)wasdevelopedandevaluatedexperimentally,anditissignificantforperformanceimprovementofSAWgassensor.