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简介：Scatteringattenuationinshortwavelengthshaslongbeeninterestingtogeophysicists.Ultrasoniccodawaves,observedasthetailportionofultrasonicwavetrainsinlaboratoryultrasonicmeasurements,areimportantforsuchstudieswhereultrasonicwavesinteractwithsmallscalerandomheterogeneitiesonascaleofmicrometers,butoftenignoredasnoisesbecauseofthecontaminationofboundaryreflectionsfromthesideendsofasamplecore.Numericalsimulationswithaccurateabsorbingboundarycanprovideinsightintotheeffectofboundaryreflectionsoncodawavesinlaboratoryexperiments.Thesimulationofwavepropagationindigitalandheterogeneousporouscoresreallychallengesnumericaltechniquesbydigitalimageofporoelasticproperties,numericaldispersionathighfrequencyandstrongheterogeneity,andaccurateabsorbingboundaryschemesatgrazingincidence.Toovercomethesedifficulties,wepresentastaggered-gridhigh-orderfinite-difference(FD)methodofBiot’sporoelasticequations,withanarbitraryeven-order(2L)accuracytosimulateultrasonicwavepropagationindigitalporouscoreswithstrongheterogeneity.Anunsplitconvolutionalperfectlymatchedlayer(CPML)absorbingboundary,whichimprovesconventionalPMLmethodsatgrazingincidencewithlessmemoryandbettercomputationalefficiency,isemployedinthesimulationtoinvestigatetheinfluenceofboundaryreflectionsonultrasoniccodawaves.Numericalexperimentswithsaturatedporoelasticmediademonstratethatthe2LFDschemewiththeCPMLforultrasonicwavepropagationsignificantlyimprovesstabilityconditionsatstrongheterogeneityandabsorbingperformanceatgrazingincidence.TheboundaryreflectionsfromtheartificialboundarysurroundingthedigitalcoredecayfastwiththeincreaseofCPMLthicknesses,almostdisappearingattheCPMLthicknessof15grids.ComparisonsoftheresultingultrasoniccodaQscvaluesbetweenthenumericalandexperimentalultrasonicSwaveformsforacylindricalrocksampledemonstratethatthe

简介：Thispaperpresentsaflexibleandhighspeeddigitalscanconverter(DSC)withtheabilitytohandlehighfrequencyultrasoundimaginginreal-time.Thecharacteristicsinimagingsystemsuchasfocuslengthoftransducer,theswingradiusandsamplinglengthetc.couldbechangedeasilyincompliancewiththeresearcher'sapplicationbasedonthisflexibledigitalscanconverter.Linearinterpolationisemployedtoachievethecoordinatetransformationsalgorithm.Custom-builtsoftwareisprogrammedtopreliminarilyhandlethealgorithmaccordingtodifferentultrasoundimagingapplications.HighperformanceFPGAwillimplementhighspeedinterpolationcalculationbasedonthepreliminarydatawhicharestoredintheDDR2SDRAMfromthesoftware.64bit66MHzPCIisemployedtoaccomplishhighspeeddatatransmission.Experimenthasshownthatmorethan500frameratecouldbeachievedbasedonthishighspeeddigitalscanconverter.ThedesignedflexibleandhighspeeddigitalscanconvertercouldbeusedincurrentFPGAbasedhighfrequencyultrasoundimagingsystem.

简介：ThepresentpapersummarizesajointeffortundertakenbytheInstitutoGeográficoMilitardeChile(IGM)andtheInstitutoAntárticoChileno(INACH)inordertoobtaindigitalcartographyoftheFildesPeninsula,ReyJorgeIsland,Antarctica.ThispeninsulaconstitutestheprototypeprojectareaforthemainIGM_INACHprojectN°153“CartographicSurveyandGeographicInformationSystemoftheSouthShetlandsIslands'TheDigitalCartographywasimplementedatthe1∶5000scale,usinggeodeticGPScontrolpointsreferencedtoITRF92andWGS84Data.TheUTMProjectionwasused.AllproductswereproducedincompliancewiththecartographicstandardsoftheIGM.ThiscartographywasdesignedinordertosatisfytherequirementsofaGeographicInformationSystemdevelopedbyINACH.Thisgeo_referenceddatabaseincorporatesavarietyofthematicinformation,enablingittosupportscientificinvestigations,environmentalandmulti_disciplinarystudies,andotherapplications.AsaresultofthisprojecttheInstitutoGeográficoMilitardeChileproducedamapat1∶5000scaleindigitalformat,andalsoa1∶10000topographicmap,inpaperformat,withtwoeditions:firsteditionoftwochartsandasecondeditionwithonechartcoveringthewholeprojectarea.Chileandothercountrieshaveanumberofimportantpermanentactivitiesinthisarea.Thesemapsaredesignedtosupportseveralanddiversegeo_spatialstudiesrelatedtotheseactivities.

简介：Targetdynamicsareassumedtobeknowninmeasuringdigitalspeckledisplacement.Useismadeofasimplemeasurementequation,wheremeasurementnoiserepresentstheeffectofdisturbancesintroducedinmeasurementprocess.Fromtheseassumptions,Kalmanfiltercanbedesignedtoreducevarianceofmeasurementnoise.Anopticalandanalysissystemwassetup,bywhichobjectmotionwithconstantdisplacementandconstantvelocityisexperimentedwithtoverifyvalidityofKalmanfilteringtechniquesforreductionofmeasurementnoisevariance.

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简介：此机作为IXYDIGITALL2的升级产品，它具备2.4倍光学变焦，显示屏为11.8万像素的1.8英寸LCD，采用DIGIC画面处理芯片。开机时间从1.8秋缩短到1.2秋，一次充电后可连续进行160张拍摄，像素为500万，最高分辨率为2592×1944，感光度ISO50/100/200/400，

简介：FortheAMANDAexperimentanewtypeofopticalmodule-thedigitalanalogopticalModule(dAOM)-hasbeendeveloped,Itincorporatessomelocal'intelligece'forslowcontrolandactiveelectronicsforanalogpulsetransmission.Morethan20dAOMprototypeshavebeensuccessfullydeployedintothepolariceduringthe1999/2000antarcticseasonandarerunningsincethattime.TheyareconnectedtothedAOMDAQboardsatthesurfacebysingletwistedparicablesoverdistancesupto2.7km.CORBAbasedclient-serverapplicationsestablishworld-wide,logicalaccesstoeverydAOM.

简介：Beetlewingsareveryspecializedflightorgansconsistingoftheveinsandmembranes.Thereforeitisnecessaryfromabionicviewtoinvestigatethematerialpropertiesofabeetlewingexperimentally.Inthepresentstudy,wehaveusedaDigitalImageCorrelation(DIC)techniquetomeasuretheelasticmodulusofabeetlewingmembrane.Specimenswerepreparedbycarefullycuttingabeetlehindwinginto3.0mmby7.0mmsegments(thegagelengthwas5mm).Weusedascanningelectronmicroscopeforaprecisemeasurementofthethicknessofthebeetlewingmembrane.Thespecimenwasattachedtoadesignedfixturetoinduceauniformdisplacementbymeansofamicromanipulator.WeusedanARAMISTMsystembasedonthedigitalimagecorrelationtechniquetomeasurethecorrespondingdisplacementofaspecimen.Thethicknessofthebeetlewingvariedatdifferentpointsofthemembrane.Theelasticmodulusdifferedinrelationtothemembranearrangementshowingastructuralanisotropy;theelasticmodulusinthechordwisedirectionisapproximately2.65GPa,whichisthreetimeslargerthantheelasticmodulusinthespanwisedirectionof0.84GPa.Asaresult,thedigitalimagecorrelation-basedARAMISsystemwassuc-cessfullyusedtomeasuretheelasticmodulusofabeetlewing.Inadditiontomembrane’selasticmodulus,weconsideredthePoisson’sratioofthemembraneandmeasuredtheelasticmodulusofaveinusinganInstronuniversaltensilemachine.TheresultrevealsthePoisson’sratioisnearlyzeroandtheelasticmodulusofaveinisabout11GPa.

简介：在这研究，数字图象关联(DIC)被采用评估牛的蹄角的机械性质。用特定的过程，张力的标本地区包括了4脚底和5从前面的爪和一头成熟黑安格斯奶牛的后面的蹄被切除。在抽取以后，标本被调节与任何一个0%的相对潮湿内容获得角(干燥)或100%(湿)然后使遭到了到单轴的紧张到失败。所有“干燥”、“湿”的蹄角的平均有弹性的模量(E)是2870瑵漠?潦吗？

简介：A320×240CMOSimagesensorisdemonstrated,whichisimplementedbyastandard0.6μm2P2MCMOSprocess.Forreducingthechiparea,each2×2-pixelblocksharesasample/holdcircuit,analog-to-digitalconverterand1-bmemory.The2×2pixelpitchhasanareaof40μm×40μmandthefillfactorisabout16%.Whileoperatingatalowframerate,thesensordissipatesaverylowpowerbypower-managementcircuitmakingpixel-levelcomparatorsinanidlestate.Adigitalcorrelateddoublesampling,whicheliminatesfixedpatternnoise,improvesSNRofthesensor,andmultiplesamplingoperationsmakethesensorhaveawidedynamicrange.

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简介：AbstractCurrently, the diagnosis of tuberculosis (TB) is mainly based on the comprehensive consideration of the patient's symptoms and signs, laboratory examinations and chest radiography (CXR). CXR plays a pivotal role to support the early diagnosis of TB, especially when used for TB screening and differential diagnosis. However, high cost of CXR hardware and shortage of certified radiologists poses a major challenge for CXR application in TB screening in resource limited settings. The latest development of artificial intelligence (AI) combined with the accumulation of a large number of medical images provides new opportunities for the establishment of computer-aided detection (CAD) systems in the medical applications, especially in the era of deep learning (DL) technology. Several CAD solutions are now commercially available and there is growing evidence demonstrate their value in imaging diagnosis. Recently, WHO published a rapid communication which stated that CAD may be used as an alternative to human reader interpretation of plain digital CXRs for screening and triage of TB.

简介：Vegetationfractionalcoverage(VFC)isoneofthekeyindicatorsofvegetationdistribution.Intheworkameasurement-basedmodelwasdevelopedtoderivetotalforestVFC(TG)aswellastheVFCoftrees(T)andshrub-grasses(G)separatelyinasubtropicalforestareainNanjing,China.Bothupwardanddownwardphotographsweretakenwithadigitalcamerain72quadrats(10m×10meach).Fifteenmodelswereestablishedandvalidated.ModelsjointlyusingbothTandGperformedbetterthanthoseusingtheTandGseparately.Thebestmodel,TG=T+G-1.134×T×G-0.025(R2=0.9115,P<0.01,rootmeansquarederror=0.0789),isrecommendedforapplication.ThismodelprovidesagoodwaytoobtaintotalforestVFCvaluesthroughtakingtreeandshrub-grassphotosongroundbelowtreecanopyratherthanabovetreecanopy.

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