简介：Thispaperdescribesanovelwavelet-basedapproachtothedetectionofabruptfaultofRotorcraftUnmannedAerialVe-hicle(RUAV)sensorsystem.Byuseofwavelettransformsthataccuratelylocalizethecharacteristicsofasignalbothinthetimeandfrequencydomains,theoccurringinstantsofabnormalstatusofasensorintheoutputsignalcanbeidentifiedbythemulti-scalerepresentationofthesignal.Oncetheinstantsaredetected,thedistributiondifferencesofthesignalenergyonalldecomposedwaveletscalesofthesignalbeforeandaftertheinstantsareusedtoclaimandclassifythesensorfaults.

简介：Theenhancedcardiaccontractilityeffectofhumanrecombinantgrowthhormone(hr-GH)onthecongestiveheartfailure(CHF)wasstudiedonthepig.Tobuildapigmodelofcongestiveheartfailure,atemporaryartificialcardiacpacemakerwasimplantedinthepig'sbodyandpacedat220beatsto240beatsperminutefor1week.Afterthemodelofcongestiveheartfailurewassuccessfullysetup,thefrequencyofthepacemakerwaschangedto150beatsto180beatsperminutetomaintaintheCHFmodelstable.Pigsweredividedintothreegroups:Thehr-GHgroupinwhich0.5mg/kgperdayofhr-GHwasadministratedintramuscularlyfor15days,theinjectioncontrolgroupinwhichanequalamountofphysiologicalsalinewasinjectedintramuscularly,andanormalcontrolgroup.Theleftventriculardiastolicendpressurewas(10.60±2.41)mmHginthehr-GHgroup,but(19.00±3.81)mmHginthesalinecontrolgroup(P＜0.01);Cardiacoutputwas(1.86±0.13)L/mininthehr-GHgroup,but(1.56±0.18)L/mininthesalinecontrolgroup(P＜0.05);Peripheralmin)-1inthesalinecontrolgroup(P＜0.05);±dp/dtmaxwas(2900±316.23)and(2280±286.36)inthehr-HGgroupandthesalinecontrolgrouprespectively(P＜0.05).Theresultsshowthathr-GHenhancesmyocardialcontractilityofCHF,andtheCHFmodelbuiltbyatemporaryartificialcardiacpacemakeratahighrateofstimulationisreasonableandapplicable.

简介：ThespinesofpencilandlanceurchinsHeterocentrotusmammillatusandPhyllacanthusimperialiswerestudiedasamodeloflight-weightmaterialwithhighimpactresistance.Thecomplexandvariableskeletonconstruction("stereom")ofbodyandspinesofseaurchinsconsistsofhighlyporousMg-bearingcalciumcarbonate.Thisbasicallybrittlematerialwithpronouncedsingle-crystalcleavagedoesnotfracturebyspontaneouscatastrophicdevicefailurebutbygracefulfailureovertherangeoftensofmillimeterofbulkcompressioninstead.Thiswasobservedinbulkcompressiontestsandbluntindentationexperimentsonregular,infiltratedandlatexcoatedseaurchinspinesegments.MicrostructuralcharacterizationwascarriedoutusingX-raycomputertomography,opticalandscanningelectronmicroscopy.Thebehaviorisinterpretedtoresultfromthehierarchicstructureofseaurchinspinesfromthernacroscaledowntothenanoscale.Guidelinesderivedfromthisstudyseeceramicswithlayeredporosityasapossiblebiomimeticconstructionforappropriateapplications.

简介：Seaurchinspineswerechosenasamodelsystemforbiomimeticceramicsobtainedusingstarch-blendedslipcasting.Porousaluminaceramicswithcap-shapedlayerswithdifferentalternatingporositieswerefoundtohavesuperiorfracturebehaviorunderbulkcompressioncomparedtoceramicswithuniformporosity.Theyfailinacascadingmanner,absorbinghighamountsofenergyduringextendedcompressionpaths.TheporosityvariationinanotherwisesinglephasematerialmimicksthearchitecturalmicrostructuredesignofseaurchinspinesofHeterocentrotusmammillatus,whicharepromisingmodelmaterialsforimpactprotection.