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15 个结果
  • 简介:Inthispaper,wegivethedistributionoftemperaturefie1dandpulsephotoacousticpressuregener-atedbypulsedlaserinliquid.Theeffectofpulsedurationandlaserbeamdimensiononthepres-suresignalisdiscussed.TheexperimentalresultsobtainedbytheGausslaserbeamdeflectiontech-niqueagreewiththetheoryqualitatively.Thistechniqueprovidesanovelopticalmethodforthecontactlessandrapidmeasurementofthermodynamicparameters.

  • 标签: DEFLECTION pulsed excitation LASER PROBING THERMODYNAMIC
  • 简介:Acousticimpulsesproducedthroughthemechanismofthelaser-inducedbreakdowninwaterhavebeeninvestigatedintherangefrom0℃toroomtemperature.Differentlyfromtheacousticimpulsesproducedviathermalexpansion,thepolarityandtheamplitudeofacousticimpulseproducedvialiquidbreakdownmechanismdonotchangewithwatertemper-ature.Thisindirectlyprovesthattheproductionofacousticimpulseisduetotheexpansionofthecavityitselfwhichincludesplasma.Asemiempiricaldescriptionofthisphenomenonisgiveninthispaper.

  • 标签: BREAKDOWN TEMPER IMPULSE dielectric polarity SURROUNDING
  • 简介:Photoacousticophthalmoscopy(PAOM)isanovelimagingmodality,whichiscapableofnon-invasivelydetectingopticalabsorptionpropertiesintheretina.WevisualizethemicrovasculatureinretinaandchoroidinalbinomouseusingPAOMguidedbyspectral-domainopticalcoherencetomography.Sincealbinomousecharacterizesbylackingmelanininretinalpigmentepithelium(RPE),PAOMilluminationlasercanpenetratethroughtheRPEontochoroid,andconsequentlyprovidesvolumetricvisualizationofchorioretinalvasculaturesasaresultofstronghemoglobinopticalabsorption.Thehigh-qualitychorioretinalmicrovascularimagingacquiredbyPAOMimpliesitsgreatpotentialinunderstandingpathologicalmechanismsanddevelopingtherapeuticstrategiesformajorchorioretinaldiseasesthatcorrelatewithvasculardisorders.

  • 标签: 视网膜血管 脉络膜 成像 小鼠 白化 光声
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  • 简介:在这份报纸,我们以可变健全速度在photoacoustic断层摄影术调查伴随方程,并且建议三个变化反复的算法。这些算法的基本想法是反复地计算原来的方程和伴随方程。我们现在的数字例子和表演这些变化反复的算法的井表演。[从作者抽象]

  • 标签: 变分迭代算法 断层扫描 SPEED 光声 伴随方程 原始方程
  • 简介:Nanocrystallinetitaniaasphotocatalysthasattractedconsiderableattentionforitspotentialuseinenvironmentalcleaning.Recently,lanthanideionsdopedtitaniasampleshavebeenshowntoincreasethephotocatalyticefficiencyofselectedreactions.Inthiswork,TiO2nanoparticlesdopedwithEr3+werepreparedviaanultrasonicassistedsol-gelmethod.Theopticalpropertiesofthesamplesweredeterminedbyphotoacoustic(PA)spectroscopy.Itwasfoundthattheabsorptionedgeshiftedtolowerwavelengthw...

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  • 简介:Thephotoacoustictomographybyusingthehandheldprobehasagreatpotentialinclinicalbreastimaging.However,theshapeoftheprobelimitsthechoiceoflightdeliveryinthissetup.Inthisletter,westudytwocommonlyusedilluminationtypesforhandheldprobe:bright-fieldilluminationanddark-fieldillumination.Ourresultsdemonstrateseveralparametershaveimportantimpactonthephotonfluenceindeepbreasttissue.Theresultswillhelptooptimizethedesignofthephotoacousticbreastimagingsystemwithahandheldprobe.

  • 标签: 手持式 探头 成像仿真 光声 光传输 乳腺
  • 简介:Thephotoacousticmodelofmultilayerwithastrong-absorbingsurfacelayerisdeveloped.Thephaseofph0toacoustiesignalismeasuredasafunctionofmodulatedfrequencyusingapparatustotallycontrolledbyacomputersystem.Thethermaldiffusivity,effusivityaswellasthicknessofseveralburiedlayersareobtainedindependentlythroughthebestfitofexperimentaldataaccordingtothetheoreticalmodel.Themultilayersofthinmetalandalloyfilmareinvestigated.Thismethodisprovedtobevaluableparticularlyinnondestructiveexaminationofsubsurfacephysicalproperties.

  • 标签: PHOTOACOUSTIC detection MULTILAYER SAMPLE BURIED properties.
  • 简介:Thisworkproposesamethodtoconcurrentlycalibratemultipleacousticspeedsindifferentmediumswithaphotoacoustic(PA)andultrasound(US)dual-modalityimagingsystem.First,physicalinfrastructureinformationofthetargetisacquiredthroughaUSimage.Then,werepeatedlybuildPAimagesaroundaspecialtargettoyieldthebestfocusedresultbydynamicallyupdatingtheacousticspeedsinadifferentmediumofthetarget.Withthesecorrectacousticpropagationvelocitiesintheaccordingmediums,wecaneffectivelyoptimizethePAimagequalityastheexperimentsproved,whichmightbenefitfutureresearchinbiomedicalimagingscience.

  • 标签: 光声层析成像 传播速度 质量优化 自适应 校正 图像质量
  • 简介:生物织物的吸收系数是在biomedicine的一个重要参数,但是它的决心仍然是挑战。在这份报纸,我们用集中photoacoustic成像技术和圆柱的扩散纤维(CDF)的内部轻照耀确定建议一个方法目标光吸收系数。为墨水吸收器的吸收系数第一在一样的刺激通过photoacoustic和spectrophotometric大小被决定,它表明这个方法的可行性。另外,有几集中的墨水吸收器的光吸收系数被测量。最后,二维的扫描photoacoustic图象被获得。光吸收系数测量和吸收器的同时的photoacoustic成像non-invasively是方法的典型特征。这个方法能为血氧浸透,基于吸收的成像和治疗的非侵略的决心起一个重要作用。

  • 标签: 光吸收系数 声测量 分光光度法测定 无损伤 内照射 光纤
  • 简介:Objective:Photoacoustic(PA)tomography(PAT)hasattractedextensiveinterestbecauseofitsopticalabsorptioncontrastandultrasonicdetection.ThisstudyaimstodevelopabiocompatibleandbiodegradablePAcontrastagentparticularlypromisingforclinicalapplicationsinhumanbody.Methods:Inthisstudy,wepresentedaPAcontrastagent:1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethyleneglycol)](DSPE-PEG)-coatedsuperparamagneticironoxide(SPIO)nanoparticles(NPs)loadedwithindocyaninegreen(ICG).WeusedICGandSPIONPsbecausebothdrugsareapprovedbytheU.S.FoodandDrugAdministration.Giventhestrongabsorptionofnear-infraredlaserpulses,SPIO@DSPE-PEG/ICGNPswithauniformdiameterof~28nmcouldsignificantlyenhancePAsignals.Results:WedemonstratedthecontrastenhancementoftheseNPsinphantomandanimalexperiments,inwhichtheinvivocirculationtimeofSPIO@DSPE-PEG/ICGNPswasconsiderablylongerthanthatoffreeICG.ThesenovelNPsalsodisplayedahighefficiencyoftumortargeting.Conclusions:SPIO@DSPE-PEG/ICGNPsarepromisingPATcontrastagentsforclinicalapplications.

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  • 简介:氨(NH3)挥发在土壤headspace是在碱的土壤,和NH3集中的氮损失的重要小径之一直接与NH3挥发被连接。氨被Fourier变换描绘中间红外线的photoacoustic光谱学(FTIR舞步)和在8501200厘米1的区域的二个典型吸收乐队被观察,它能在土壤headspace被用于NH3集中的预言。从诺思中国的碱的土壤在三个授精处理(没有N输入(CK)的控制,脲和涂的脲)下面涉及土壤孵化,壶和地实验。在土壤headspace的氨集中在每个实验被决定。在土壤孵化实验,NH3排出物被N输入开始,在白天2上到达了最高的集中,并且减少了到在在8d以后的CK测量了的水平,与在与涂的脲处理相比的脲处理的显著地更高的NH3排出物,特别在开始的4d期间。在壶实验的土壤headspace的NH3集中在孵化实验作为那显示出类似的动力学;然而,在在地实验的土壤headspace的NH3集中孵化和壶实验与那些表明了一个显著地不同的排放模式,并且为NH3集中有4-d延期。因此,在孵化的NH3集中和壶实验不能直接被用来象土壤温度和土壤骚乱一样在授精方法和申请率由于差别在这块地里为真实NH3排放建模。在控制版本的授精和参与以后在第二个星期内点亮灌溉,这被推荐涂的脲能被用来显著地减少从NH3挥发的观点的N损失。

  • 标签: 红外光声光谱 碱性土壤 氨浓度 傅里叶变换 光谱测量 中红外
  • 简介:Measurementoflightdistributioninbiologicaltissuecontributestoselectingstrategyandoptimizingdoseforbiomedicalapplication.Inthisletter,aphotoacousticmethodcombinedwithMonteCarlosimulationwasusedtoestimatethethree-dimensionallightdistributioninbiologicaltissue.Thelightdistributionwasproducedbyacylindricaldiffuserwhichinterposedintotissues.Thelightprofilesobtainedbythemethodwerecomparedtothosedetectedbyphotodiodes.Theexperimentalresultsdemonstratethefeasibilityofthismethod.Theapproachcanplayasignificantroleforphoto-dosimetryinbiomedicalphototherapy.

  • 标签: 生物组织 光分布 扩散器 光声成像 三维 圆柱形