简介:Theinfluenceofexternallowfrequency(0-100Hz)vibrationonthetip-sampleinteractioninSPMisthemainconcernofthispaper.Aconcept,vibrationrejectionratio(VRR)proposedbyThompsonetal,wasinvestigatedtheoreticallyandexperimentally.Aconcisetheoreticalbackgroundwasintroduced,avibrationstimulatingandmeasuringsystemforSPMwasbuiltup,andanexperimentalresearchoftheinfluenceonSPMVRRwascarriedoutwithdifferentSPMprobes,samples,tippre-loadsandopen/closeloopsoftip-sampleinteraction.ItwasprovedbothintheoryandexperimentthatSPMVRRhadcorrelationswiththespringconstant,theairdampingconstant,theeffectivemassofthecantilever,thecontactspringconstantandthecontactdampingconstantbetweentipandsample.SPM'svibrationrejectingabilitycanbeimprovedbylongercantileverprobe,softersamplesurface,greatertippre-load,andclose-loopcontrolfortip-sampleinteraction.Moreattentionshouldbepaidtoapropercombinationoftheaboveparameters.
简介:无
简介:Amodelofquasi-CPA(chirpedpulseamplification)system,inwhichtheinputisthetransform-limitedGaussianpulses,issetupnumericallytoinvestigatetheimpactofthesecondorderdispersionontheadaptivecompensationofself-phasemodulation(SPM)effect.Theadaptivephasepre-shapingcontrolledbydifferentialevolutionalgorithmisintroducedtotheinputpulsebeforeamplificationandrecompression.Withmaximizingthepeakpoweroftheoutputpulse,thesimulationresultsshowthatthenormaldispersionisreallyhelpfultoeliminatethesidelobesoftheoutputpulseandincreasethepulsepeakpower.
简介:摘要:目的 探究新生儿缺氧缺血性脑病病理机制中脑血管内皮的功能,或许与SPM促脑发育训练增加脑血管剪切力介导的PECAM-1/eNOS/NO通路调控相关联,并最终实现了脑保护作用。方法 选择成年雄性蒙古沙鼠(60-80 克),沙鼠腹腔注射戊巴比妥钠1% (v/w)麻醉,夹闭双侧颈总动脉5分钟诱导缺血,后松解恢复血流。不同组采用SPM促脑发育训练手段,最终分别检测各组的组织形态、蛋白及凋亡检测等相关数据。结果 SPM促脑发育训练可以增加剪切力,继而作用于PECAM-1/eNOS/NO通路影响脑血管内皮功能,内皮功能改善有助于缺氧缺血性脑病的康复。结论 SPM促脑发育训练增加脑剪切力,剪切力通过PECAM-1/eNOS/NO通路改善血管内皮功能,继而改善缺氧缺血性脑病介导的脑损伤。