简介：胎儿缺氧常见,是引起围生期残障和死亡的主要原因[1,2]。更重要的是,近年来的研究证实了胎儿宫内慢性缺氧是日后成人慢性疾病包括肥胖、高血压、糖尿病、代谢综合征、动脉粥样硬化的主要易感因素之一[3-9]。因此,产前Doppler超声检测胎儿缺氧并加以干预具有重要的意义。本文主要介绍Doppler超声检测胎儿缺氧方法及其注意事项,如何分析并诊断,如何定量评价胎儿宫内缺氧及其严重程度。

简介：７１４ＳＤＤＯＰＰＬＥＲＷＥＡＴＨＥＲＲＡＤＡＲＳＹＳＴＥＭ￥ＧｅＲｕｎｓｈｅｎｇ（葛润生），ＺｈａｎｇＰｅｉｙｕａｎ（张沛源）ａｎｄＰｅｎｇＨｏｎｇ（彭红）７１４ＳＤＤＯＰＰＬＥＲＷＥＡＴＨＥＲＲＡＤＡＲＳＹＳＴＥＭＧｅＲｕｎｓｈｅｎｇ（葛润生），...

简介：ADopplersodarsystemcontrolledbymicrocomputerisdescribedinthispaper.Thesodarwasusedtodetecttheverticaldistributionofwindandtemperaturestratificationintheatmosphericboundarylayer.Thedetectingresultsshowthatatnighttheverticaldistributionofwindisverycomplicated,whichcanappearasastructureoftwoorthreelayers.Innocturnalatmosphericboundarylayersometimesthereexistsverythinlayerinmulti-layerinversionanditcanberetainedforalongtime.

简介：Windshearreflectsthatthewindfieldisnotuniform,whichisoneoftheprimaryfactorswhichmaketheretrievalofthewindfielddifficult.Basedonvolumevelocityprocess(VVP)windfieldretrievaltechnique,theintensityofwindshearisidentifiedinthispaper.Afteranalyzingthetraditionaltechniquesthatrelyonthedifferenceofradialvelocitytoidentifywindshear,afixeddifferenceamongradialvelocitiesthatmaycausefalseidentificationinauniformwindfieldwasfound.Becauseofthenon-uniformityinwindshearareas,thedifferenceofretrievedresultsbetweensurroundinganalysisvolumescanbeusedasameasurementtoshowhowstrongthewindshearis.AccordingtotheanalysisofasevereconvectiveweatherprocessthatoccurredinGuangzhou,itcanbefoundthattheareasofwindshearappearedwiththestrengthsignificantlylargerthaninotherregionsandthemagnitudegenerallylargerthan4.5m/(s·km).Besides,bycomparingthevariationofwindshearstrengthduringtheconvection,itcanbefoundthatnewcellswillbemorelikelytogeneratewhenthestrengthisabove3.0m/(s·km).Therefore,theanalysisofstrongwindshear'smovementanddevelopmentishelpfultoforecastingsevereconvections.

简介：Todetectthelaserdopplersignal,theunknownsignalistrackedbytheknownsignalusingtheconceptoftopologicalcontravariance.TheunknowntopologicalspaceUandknownspaceMarefounded,andthentheunknownsignal'stransformationistrackeddynamicallyaccordingtothismappingrelationshipbetweenthetwospaces.Thesystemequationisobtainedbygradient-descentmethod,andtheconditionsofstabilityaregivenbyPoincarémapping.Theproposedmethodisappliedtomeasurethein-planedisplacementsignalofthesolid50mawayusinglaserdoppler,signal.Theresultprovesthatthemethodcandetectlaserdoppler.signalaccurately,itsrelativeerrorislessthan0.7%.

简介：目标结构的机械颤动将调制雷达backscattering的阶段函数，并且将从目标导致返回的信号的频率调整。它产生目标身体Doppler频率的乐队转移的一个方面，它对目标识别有用。基于这，micro-Doppler原子宝库为目标识别被造，并且四种普通分类器独立被使用执行分类识别。模拟试验性的结果证明这个方法让高识别超过90%评价。

简介：

简介：AjammingsuppressionmethodbasedonpolarizationsignaldetectionisproposedundercommonrangeandvelocitycheatingjammingforpulseDopplerradar.Onthebasisoftheseparationofthetargetandthejamming,therangeandvelocitytrackonthetruetargetarerealized.FirstlythesignalprocessingmodelofthefullpolarizationpulseDopplerradarisintroduced.Secondlythemethodofcorrecttargetseparationisdiscussed,whichisthetwicedetectionsofenergyandpolarizationstateonthetwodimensionresolutioncellsofrangeandvelocityoftheradarecho.Finallythesimulationsareperformedandtheresultsprovethevalidity.What'smore,multiplerangeandvelocitycheatingjammingcanbesuppressedatthesametimeifthetargetandthejammingaredifferentinthepolarizationdomain.

简介：Range-Doppler(RD)methodandReverse-Range-Doppler(RRD)methodarecombinedtogethertoachieveautomaticgeocodingofSyntheticApertureRadar(SAR)imagequicklyandaccuratelyinthepaper.TheRDmethodisfirstlyusedtolocatethefourcornersoftheimage,thentheotherpixelsoftheimagecanbelocatedbyReverse-Range-Doppler(RRD)method.Resamplingisperformedatlast.Theapproachhasanadvantageoverprevioustechniquesinthatitdoesnotrequiregroundcontrolpointsandisindependentofspacecraftattitudeknowledgeorcontrol.ItcancompensatetheshiftduetotheassumedDopplerfrequencyinSARimagepreprocessing.RRDsimplifiestheprocessofRD,thereforespeedsupthecomputation.TheexperimentalresultsshowthataSARimagecanbeautomatedgeocodedin30susingthesingleCPU(3GHz)with1Gmemoryandanaccuracyof10misattainablewiththismethod.

简介：Objective:　ToinvestigatethevalueoftranscranialDoppler(TCD)ultrasonographyinevaluatingtheoutcomeofseveretraumaticbraininjuryandtocorrelatetheTCDvalueswithintracranialpressure(ICP)andcerebralperfusionpressure(CPP)monitoring.　　Methods:　AprospectivestudywasconductedtoevaluatethecontributionofTCDultrasonographytoneurologicaloutcomeinaseriesof96severetraumaticbraininjurypatients.ThequantitativevariablesofTCDultrasonographyincludedthemeanbloodflowvelocityofthemiddlecerebralartery(MCA)andpulsatilityindexwithinthefirst24hoursofadmission.TheICPandCPPvalueswerealsorecorded.Outcomein6monthspostinjurywasevaluatedusingtheGlasgowOutcomeScale(GOS4-5wasconsideredas“good”andGOS1-3as“poor”).　　Results:　ThemeanbloodflowvelocityoftheMCAwaslargerthan40cm/sin30(51%)patientswithgoodoutcomewhereasitwaslessthan40cm/sin27(73%)patientswithpooroutcome(P<0.025).ThemeanPIincasesofgoodoutcome(34patients,57%)waslowerthan1.5whereasinpooroutcome(30patients,83%)washigherthan1.5(P<0.001).ThecorrelationsofICPandCPPtopulsatilityindexwerestatisticallysignificant(P<0.01).　　Conclusions:　TCDultrasonographyisvalidinpredictingthepatientsoutcomeof6monthsandcorrelatessignificantlywithICPandCPPvalueswhenitisperformedinthefirst24hoursofseveretraumaticbraininjury.

简介：Inanactiveradar-trackingsystem,thetarget-motionmodelisusuallymodeledintheCartesiancoordinates,whiletheradarmeasurementusuallyisobtainedinpolar/sphericalcoordinates.Thereforethetarget-trackingproblemintheCartesiancoordinatesbecomesanonlinearstateestimationproblem.Anumberofmeasurement-conversiontechniques,whicharebasedonpositionmeasurements,arewidelyusedsuchthattheKalmanfiltercanbeusedintheCartesiancoordinates.However,theyhavefundamentallimitationstoresultinfilteringperformancedegradation.Infact,inadditiontopositionmeasurements,theDopplermeasurementorrangerate,containinginformationoftargetvelocity,hasthepotentialcapabilitytoimprovethetrackingperformance.AfilterisproposedthatcanuseconvertedDopplermeasurements(i.e.theproductoftherangemeasurementsandDopplermeasurements)intheCartesiancoordinates.ThenovelfilteristheoreticallyoptimalintheruleofthebestlinearunbiasedestimationamongalllinearunbiasedfiltersintheCartesiancoordinates,andisfreeofthefundamentallimitationsofthemeasurement-conversionapproach.Basedonsimulationexperiments,anapproximate,recursiveimplementationofthenovelfilteriscomparedwiththoseobtainedbyfourstate-of-the-artconversiontechniquesrecently.Simulationresultsdemonstratetheeffectivenessoftheproposedfilter.

简介：在医药Doppler超声系统，是的一个高通行证的过滤器通常采用了过滤墙喧嚷部件，将移开未经触动的Doppler超声血表明的低速度血flow.To摘录的信息，一条新奇途径基于空间地选择的噪音过滤被建议。墙信号被空间地选择的噪音过滤第一从小浪估计空间关联性质。然后，墙喧嚷被降噪消除剩余血流动信号的技术的小浪阀值确切获得。最后，未经触动的血流动信号被从混合信号减去墙信号完成。这条途径被用于模仿的计算机并且在vivo颈动脉Doppler超声信号。实验结果证明基于的小浪空间来临能确切提取血流动信号，并且比高通行证的过滤的在吝啬的绝对错误完成大约45%更低的结果。这条途径被期望是一个有效方法在Doppler超声系统移开墙喧嚷。

简介：与从Shantou和厦门和公民的Doppler雷达数据，环境预言和公民的中心为大气的研究(NCEP/NCAR)分析数据集中，台风Chanchu在2006年5月17日引起的短期的重暴风雨的特征被学习。Doppler雷达数据显示在从1800～19005月17日的时期期间，积极、否定的光线的风最大值的方位角的阶段在台风的核心半径附近是不对称的，即，轨道的左边上的光线的风在右边上比那反常地大。研究证明这被冷空气的侵入导致(在东北弯屈)，它首先在中间降低层被定位，比4km低；这由于强迫空气高举的侵入的冷空气，提高不稳定性精力的版本，它触发重降水。在冷空气活动的迟了的阶段期间，台风很快被削弱。与冷空气的观察雷达的侵入一致，风数据的NCEP/NCAR分析也证明在台风中心(18005月17日)左边在中间降低层(近似1-3km)有明显的大分级的风价值，并且在所有区域除了，侵入的寒冷影响的那些通风--轨道的右边上的风速度在左边上仍然保持比那些大。而且，Rankine模型结果证实在东北冷的空气在轨道左边在中间降低层被介绍给台风。计算也指出那在那里存在有与高度和发生在福建省的南方的超级重暴风雨向西北从东南倾斜到的高se的一个正面的地区就在正面的地区附近躺。

简介：在这份报纸，卫星转菠在空中的bistaticSAR(SA-BiSAR)的一个特殊几何学盒子被考虑，在哪个卫星和飞机飞行路径是平行的，他们的天线在长带地图正在驾驶。这个盒子是一个简单却典型的申请例子，它为非合作的照明是适用的。SA-BiSAR系统的集成时间经由传输器和接收装置脚印的运动被导出。在平行和stripmap模式，Doppler频率通过在卫星转菠、在空中的SAR之间的联合被获得。另外的Doppler性质被想象，包括Doppler带宽和方位角分辨率。全面模拟实验被进行，一些特征被展出。批评参数，在SA-BiSARDoppler性质上有重要效果，被分析表情和数字模拟提取。在平行和长带地图模式并且与ENVISAT-1的参考，SA-BiSAR系统拥有经由模拟结果的分析产出为C乐队的10m方位角分辨率和0.5s集成时间的潜力。

简介：Vehicularnodepositioningneedstobequickandpreciseonhighwayforsafetyconsidera-tion.Inthispaper,wepresentanovelandpracticalvehicularnodepositioningmethodwhichcanachieveahigheraccuracyandmorereliabilitythantheexistingglobal-positioning-system-basedpo-sitioningsolutionsbymakinguseofDoppler-shiftedfrequencymeasurementstakenbyvehicularnodeitself.Thispositioningmethodusesinfrastructurenodeswhichareplacedontheroadsideeveryseveralkilometersasradiationsourcestoestimatetherelativedistancesofvehicletotheinfrastructurenode.Throughcoordinateconversion,wegettheabsolutecoordinatesofvehicularnodebasedonknownabsolutecoordinatesofinfrastructurenode.Wealsoanalyzetheoptimaldistanceofneighborinfra-structurenodesinordertoensureahighaccuracy.Inaddition,simulationresultsdemonstratethattheaccuracyofourmethodwithExtendedKalmanFiltering(EKF)issuperiortothemethodwithoutEKF.

简介：台风Rananim(0414)被从分析的中心和暴风雨(帽子)的预言使用非静水力学的先进地区性的预言系统(ARPS)模仿了。Rananim的预言通常用新一代CINRADDoppler雷达数据与ARPS被改进了。有那或没有使用数据显示出的雷达的数字实验与在ARPS的光线的速度数据能改变的吸收雷达为起始的域建模在对流层的中间和高水平的风域；热带气旋(TC)的好特征被介绍进起始的风，TC的风速度南方的x部件被增加那么它向西是y部件。他们导致在时间TC轨道预报改进在以后乍见陆地。混合混合比率的比率，温度，云水混合比率和雨水的水蒸汽的地被使用雷达反射率数据也改进了。模型对hydrometeors的介绍的起始的反应被增加了。水平模型分辨率在紧张预报上有重要影响，这被显示出，由极大地改进特殊预报TC的TC降雨，和重暴风雨，以及它有时间的分发和变化。

简介：Ubiquitousradarisanewradarsystemthatprovidescontinuousanduninterruptedmultifunctioncapabilitywithinacoveragevolume.Continuouscoveragefromclose-in'pop-up'targetsincluttertolong-rangetargetsimpactsselectionofwaveformparameters.Thecoherentprocessinginterval(CPI)mustbelongenoughtoachieveacertainsignal-to-noiseratio(SNR)thatensurestheefficiencyofdetection.TheconditionofdetectioninthecaseoflowSNRisanalyzed,andthreedifferentcasesthatwouldoccurduringintegrationarediscussedandamethodtodeterminetheCPIispresented.ThesimulationresultsshowthattargetsdetectionwithSNRaslowas-26dBintheexperimentalsystemcanpossiblydeterminetheCPI.

简介：

简介：UsingsingleDopplerweatherradarechoinformation,thispaperpresentsatechniqueforrecognizingtwo-di-mensionalflowfieldstructureoftheseverestormandestimatingthedivergence,thevorticity,andtheintensityofwindshearline,andgivessomeexamples.

简介：由广东的力量供应商在2004在广州和闪电数据基于CINRADDoppler雷达数据，统计学习被在雷达的回响上覆盖闪电的位置做。结果显示出下列。更多的否定闪电在发生在中间的层次(2-14km)的集中的时期在雷达回响是中等的的地方(12-45dBz)，而非在有最弱的回响的底层或在有最强壮的回响的高水平。在层次3-11km，在雷达回响在10dBz和35dBz之间的地方，否定闪电的区域比在省的其余部分在中央广东是大得多的。在雷达回响在44dBz和51dBz之间的层次0.5-7km，为一个点的概率从0.4～0.7变化有否定闪电。