简介:目的:探讨超声e-flow技术结合梯形成像在下肢交通支静脉功能不全诊断中的作用。方法回顾性分析23例行交通静脉结扎手术患者的超声图像,术前利用超声e-flow技术结合梯形成像检出交通支静脉,将其定位结果与手术结果比较,以检验其准确率。结果下肢交通支静脉功能不全表现为朝向体表的条状或网状血流,超声检出功能不全的交通支静脉47条,手术发现交通支静脉56条,以手术结果为金标准,诊断准确率为83.9%。结论超声e-flow技术结合梯形成像能准确诊断和定位功能不全的交通支静脉,有助于术中寻找需结扎的交通支静脉。
简介:目的探讨E-Flow血流显像技术对胎儿冠状动脉瘘的诊断价值。方法在胎儿超声心动图检查中除使用常规彩色多普勒外加用了E—Flow血流显像技术,产前诊断冠状动脉瘘5例。使用Alokaod0彩色超声诊断仪,探头频率为3.5~5.0MHz。对二维超声(2D)发现胎儿一侧心房、心室异常增大或冠状动脉增粗的患者,进一步探查冠状动脉。先以彩色多普勒超声(CDFI)获取心腔内异常血流,再以连续多普勒(CW)获取舒张期为主的高速血流频谱.初步证实该异常血流来自于冠状动脉。此时启动E-Flow显像模式追溯该异常血流。结果5例胎儿冠状动脉瘘均出生后经超声证实。其中2例为左冠状动脉右心室瘘、1例为左冠状动脉右心房瘘,1例为右冠状动脉右心房瘘,1例为右冠状动脉右心室瘘。E-Flow显像技术能够敏感地捕捉冠状动脉瘘血流,清晰显示冠状动脉瘘的起源、瘘管的走行以及瘘口的位置、大小,其血流显像优于传统的彩色多普勒。结论应用E-Flow显像技术可以在产前更加准确、快速地诊断胎儿冠状动脉瘘。推荐E—Flow血流显像技术成为胎儿冠状动脉瘘的诊断工具之一。
简介:Steadywatersurfaceprofileofgraduallyvariedflowcanbecalculatedusingei-therasteadyflowapproachoranunsteadyflowapproach.Thesteadyflowapproachrequiresit-erativeprocedureswhichmayhaveconvergenceproblemsunlessthestepsize1xislessthanamaximumvalue△x.Theunsteadyflowapproachbasedontheexplicitcharacteristicmethodhasastabilityproblemunless△xislessthan△x.Aseriesofnumericalexperimentswerecarriedoutandtheresultsoftwoapproachesarecompared.
简介:摘要目的探讨超声E成像联合超声造影在甲状腺癌筛查中的诊断价值。方法回顾分析甲状腺结节患者 477 例(共613个结节),均进行超声造影和超声E成像检查,以病理检查结果为参照,比较单纯超声造影和超声E成像联合超声造影在甲状腺癌诊断中的准确度、敏感性和特异性,并分析两种检查方案的阳性似然比。结果病理检查结果显示,甲状腺良性结节496个,甲状腺癌117个。超声E成像联合超声造影在鉴别甲状腺良、恶性中的准确度(90.37%)高于单纯超声造影(84.01%),差异具有统计学意义(χ2=11.111,P=0.001);超声E成像联合超声造影诊断甲状腺癌的敏感性(81.20%)低于单纯超声造影(86.32%),但差异无统计学意义(χ2=1.131,P=0.376);其特异性优于单纯超声造影(92.54%比83.46%),差异具有统计学意义(χ2=19.336,P<0.001)。超声E成像联合超声造影诊断甲状腺癌的阳性似然比为10.885,表明其诊断甲状腺癌的可能性显著增加。结论超声E成像联合超声造影可提高诊断甲状腺癌的准确性,使患者避免不必要的侵入性操作。
简介:ThesupersonicductflowwithfixedbackpressuretostagnationpressureratioPb/P0underheatingisinvestigatedanalytically.A“FlowPatternDiagram”Whichconsistsofsixpatternzonesisdeveloped.BythisdiagramtheactualflowstateinsupersonicductflowsystemcanbedeterminedconvenientlywhenPb/Poandheatingintensityareknows.Itisimpossibleforflowwithheavyheatingtobecomesupersonic,eventhoughthepressureratioismuchsmallerthanthecriticalpressureratio,Basedontheanalogybetweenviscouseffectandheatingeffectathermaldragfactorhaseendefined.whichcanpredicttheflowpropertyvariationduetoheatingandtherelaiveimportanceofviscouseffectandheatingeffect.
简介:摘要目的探讨超声显像与B-Flow技术在下肢深静脉血栓病变的诊断及应用。方法选取2015年4月~2016年4月我院收治的118例患者为研究对象,回顾分析其临床资料,在诊断中应用超声显像与B-Flow技术,观察其血栓情况。结果本组118例患者,确诊率100.00%(118/118),双下肢血栓8例、单下肢血栓110例,急性下肢深静脉血栓90例、慢性下肢深静脉血栓28例,研究组的股静脉与腘静脉内径值均大于正常组,差异有统计学意义(P<0.05)。同时,本组患者中59例血管呈无回声,29例呈自发显影,10例呈实质性低回声,20例呈稍强回声。结论在诊断下肢深静脉血栓病变时应用超声显像与B-Flow技术,提高了诊断准确率,并且安全可靠,值得推广。
简介:Allexistingprotonexchangemembrane(PEM)fuelcellgasflowfieldshavebeendesignedonthebasisofsingle-phasegasflowdistribution.Thepresenceofliquidwaterintheflowcausesnon-uniformgasdistribution,leadingtopoorcellperformance.Thispaperdemonstratesthatagasflowrestrictor/distributor,asiscommonlyusedintwo-phaseflowtostabilizemultiphasetransportlinesandmultiphasereactors,canimprovethegasflowdistributionbysignificantlyreducinggasmal-distributioncausedbyeithernon-uniformwaterformationinparallelflowchannelsorflowinstabilityassociatedwithnegative-slopepressuredropcharacteristicoftwo-phasehorizontalflowsystems.
简介:Experimentswereconductedtoinvestigatetheeffectofimpellergeometryandtongueshapeontheflowfieldofcrossflowfans.Threeimpellers(Ⅰ,Ⅱ,Ⅲ)havingsameouterdiameter,butdifferentradiusratioandbladeangleswereemployedfortheinvestigation.Eachimpellerwastestedwithtwotongueshapes.Flowsurveywascarriedoutforeachimpellerandtongueshapeattwoflowcoefficients.andforeachflowcoefficientatdifferentcircumferentialpositions.Theflowistwo-dimensionalalongthebladespanexceptneartheshrouds.Thetotalpressuredevelopedbytheimpellersineachcaseisfoundtobemaximumatacircumferentialpositionofaround270°.Thetotalandstaticpressuresattheinletofimpellersaremoreorlesssameregardlessofimpellerandtonguegeometry,buttheyvaryconsiderablyatexitoftheimpellers.ImpellerⅢwithtongueT2developshighertotalpressureandefficiencywhereasimpellerⅡwithtongueT2developsminimumtotalpressure.HigherdiffusionandsmallervortexsizearethereasonsforbetterperformanceofimpellerⅢwithtongueT2。
简介:BasedonthePreissmannimplicitschemefortheone-dimensionalSaint-Venantequation,themathematicalmodelforone-dimensionalrivernetworksandcanalnetworkswasdevelopedandthekeyissuesonthemodelwereexpatiatedparticularlyinthisarticle.Thismodelappliesthemethodofthree-stepssolutionforchannel-junction-channeltosimulatetherivernetworks,andtheGausseliminationmethodwasusedtocalculatethesparsematrix.Thismodelwasappliedtosimulatethetree-typeirrigationcanalnetworks,complexloopedchannelnetworksandtheLowerColumbiaSloughnetworks.TheresultsofwaterlevelanddischargeagreewiththedatafromtheAdlulandfielddata.Themodelisprovedtoberobustforsimulatingunsteadyflowsinrivernetworkswithvariousdegreesofcomplexstructure.Thecalculatedresultsshowthatthismodelisusefulforengineeringapplicationsincomplicatedrivernetworks.Futureresearchwasrecommendedtofocusonsettingupecologicalnumericalmodelofwaterqualityinrivernetworksandcanalnetworks.
简介:Theformulaswhicharesuitabletobirefringentmediumwithsymmetricplanearederivedbymeansofphaseretardintegration.Wehaveadoptedthisconcepttotheaxisymmetricproblemsanddeducedsomeusefulformulasforthesecases.Asapracticalapplication,thestrainrateanalysisofflowinadivergingoraconvergingvesselisillustratedattheendofthispaper.