简介：Inthispaper,weinvestigatetheroleofmorphingonflightdynamicsoftwobirdsbysimulatingtheflowoverrigidandmorphingwingsthathavethecharacteristicsoftwodifferentbirds,namelytheGiantPetrelandDovePrion.Thesimulationofaflappingrigidwingshowsthattherootofthewingshouldbeplacedataspecificangleofattackinordertogenerateenoughlifttobalancetheweightofthebird.However,inthiscasethegeneratedthrustiseitherverysmall,orevennegative,dependingonthewingshape.Further,resultsshowthatmorphingofthewingenablesasignificantincreaseinthethrustandpropulsiveefficiency.Thisindicatesthatthebirdsactuallyutilizesomesortofactivewingtwistingandbendingtoproduceenoughthrust.Thisstudyshouldfacilitatebetterguidanceforthedesignofflappingairvehicles.

简介：Theeffectofpiezoelectricityonphononpropertiesandthermalconductivityofgalliumnitride(GaN)nanofilmsistheoreticallyinvestigated.TheelasticitymodelisutilizedtoderivethephononpropertiesinspatiallyconfinedGaNnanofilms.ThepiezoelectricconstitutiverelationinGaNnanofilmsistakenintoaccountincalculatingthephonondispersionrelation.Themodifiedphonongroupvelocityandphonondensityofstateaswellasthephononthermalconductivityarealsoobtainedduetothecontributionofpiezoelectricity.TheoreticalresultsshowthatthepiezoelectricityinGaNnanofilmscanchangesignificantlythephononpropertiessuchasthephonongroupvelocityanddensityofstates,resultinginthevariationofthephononthermalconductivityofGaNnanofilmsremarkably.Moreover,thepiezoelectricityofGaNcanmodifythedependenceofthermalconductivityonthegeometricalsizeandtemperature.TheseresultscanbeusefulinmodelingthethermalperformanceintheactiveregionofGaN-basedelectronicdevices.

简介：Thestructuraldeformationvelocityplaysasignificantroleinthedynamiccalculationofundergroundblast-resistantstructures.Themotiondifferentiatingequationofastructuresystemtakingintoaccounttheroleofdeformationvelocityofthestructurewilltruthfullydescribetheactualsituationofstructuralvibration.Withtheone-dimensionalplanewavetheory,theexpressionofloadonthestructuralperipheryisdeveloped,andthegeneralizedvariationprincipleforthedynamicanalysisofundergroundarched-barstructuresisgiven.Atthesametime,theresultsofthenumericalcalculationarecompared.

简介：Thetsunamiwasasuddenmarinedisasters.Tsunamiwavescanquicklyspreadtonear-shoreandcausethedisasterafterthetsunami.Soitisveryimportantoftimelymonitoringandearlywarningofthetsunami.Afterseveralunsuccessfultsunamiforecasting,theUnitedStatesdevelopedtsunamibuoyspecificallyfortheearlydetectionoftsunamiwaves.Tsunamibuoycannotonlybeabletodisplayoccurrenceofthetsunami,itisrealtimedatabutalsobeassimilatedintothetsunamiwarningsystem,toimprovetheaccuracyofthetsunamiforecasting.Severaltsunamieventsintherecentfewyearshaveproventheimportantroleofthetsunamibuoys.Subsequently,thetsunamiwarningsystembasedontsunamibuoyswasintoregularoperation.ThesystemaccuratelypredictedtheresultsonMarch11,2011Japantsunamievent.StateOceanicAdministration(SOA),Chinaalsodeployed2tsunamibuoysintheSouthChinaSea(SCS),whichalsoplayedanimportantroleinthewarningprocessofJapantsunamionMarch11,2011.NationalMarineEnvironmentalForecastingCenter/StateOceanicAdministration(NMEFC/SOA)willcollaboratewithPacificMarineEnvironmentalLaboratory/NationalOceanicandAtmosphericAdministration(PMEL/NOAA)todevelopassimilationmethodmakinguseofrealtimedataoftsunamibuoyandbuildaforecastingsysteminSCSinthefuture.