简介：TheLS-SVM(Leastsquaressupportvectormachine)methodispresentedtosetupamodeltoforecasttheoccurrenceofthunderstormsintheNanjingareabycombiningNCEPFNLOperationalGlobalAnalysisdataon1.0°×1.0°gridsandcloud-to-groundlightningdataobservedwithalightninglocationsysteminJiangsuprovinceduring2007-2008.Adatasetwith642samples,including195thunderstormsamplesand447non-thunderstormsamples,arerandomlydividedintotwogroups,one(having386samples)formodelingandtherestforindependentverification.ThepredictorsareatmosphericinstabilityparameterswhichcanbeobtainedfromtheNCEPdataandthepredictandistheoccurrenceofthunderstormsobservedbythelightninglocationsystem.Preliminaryapplicationstotheindependentsamplesfora6-hourforecastofthunderstormeventsshowthatthepredictioncorrectionrateofthismodelis78.26%,falsealarmrateis21.74%,andforecastingtechnicalscoreis0.61,allbetterthanthosefromeitherlinearregressionorartificialneuralnetwork.

简介：摘要：针对传感器信号采集系统中出现的误差，引入了基于最小二乘支持向量机（LS—SVM）的信号自适应补偿方法，以保证采集信号的准确度。介绍了常用的信号补偿方法，在此基础上提出了基于LS—SVM的补偿算法，并利用MATLABQuartusII软件进行仿真。结果表明该方案正确有效。

简介：为提高某轿车保险杠的耐撞性，根据GB17354-1998标准，在LS—DYNA软件中建立虚拟碰撞试验的有限元模型，对不同车体边界条件、材料屈服强度和地面摩擦系数下的主梁和吸能盒变形以及系统内能进行了对比分析，探讨了这些参数对保险杠耐撞性的影响．研究表明：依据实际试验情况，车体边界条件应设为不固定；合理组合主梁和吸能盒的屈服强度可提高保险杠耐撞性；地面摩擦系数增大，保险杠吸能量增加．

简介：Thestudypresentedhereininvestigatedthemaincharacteristicsofcarbonmonoxideintraseasonalvariabilityandevaluateditspossibleimpactfactorsusingtheuppertroposphereandlowerstratosphere(UT/LS)AuraMicrowaveLimbSounder(MLS)observationsoverTibetanPlateauanditsadjacentareasinsummer(JunetoAugust)of2005and2006.ObservationsshowapersistentconstituentextremeextendingupintotheUT/LSthroughoutsummer,aswellasatemporallyreversedphasevariationbetweenthecarbonmonoxideandozoneinUT/LS.Theintraseasonaloscillations(ISOs)ofcarbonmonoxideduringsummerareinvestigatedbyusingmethodsofwaveletandbandpassfilteranalysis.ItisfoundthatISOsovertheTibetanPlateauhaveperiodsof10to20daysand30to60days.Theformermainlyappearedinuppertropospherewhilethelatterinlowerstratosphere.FurtheranalysisshowsthatthesetwoperiodsofISOsinUT/LSaremainlyinphasetotheactivitiesofconvectionoverthesouthoftheplateauandthevariationofSouthAsiaHigh,respectively.TheabovetwofactorsandtheirdynamicalcouplingmayberesponsibleforthetracerISOsatdifferentlevels.

简介：摘要目的评价VITEK2-compact微生物鉴定仪对产EsβLs菌株快速检测的可靠性。方法应用标准的纸片扩散方法对临床已分离出的大肠埃希菌和肺炎克雷伯菌产ESβLs进行确证试验。同时，应用VITEK2-compact微生物鉴定仪进行检测，将两种方法在时间和检出率上的差异进行比较。结果同时检测的两种方法，42株肺炎克雷伯菌ESβLs检测符合率达93.5％，66株大肠埃希菌ESβLs检测符合率达96.3％。标准纸片扩散法平均检测时间为18h，而VITEK2-compact微生物鉴定仪的平均检测时间为6.5h。结论VITEK2-compact微生物鉴定仪不仅能快速准确检测产ESβLs的肺炎克雷伯菌和大肠埃希菌，而且结果可靠。