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简介：High-frequencyimagetechniquehasbeenwidelyappliedinmedicaldiagnosisrecently.Forhighvoltageprotection,highspeedstageandtriggercontrolcircuitryaredifficulttoimplementahigh-frequencyultrasoundimagingsystem.Inthisstudy,weutilizedalinearservowithhighnoisetoleranceandanovelmulti-depthexpressionmethodtoovercomethoseissuesindevelopedhigh-speedimagesystem.B-modeimageofthechickenphantomby25MHztransducershowstheresolutionoflateralandaxialresolutionsareupto123μmand59μmrespectively.Inaddition,theexperimentdemonstratesthattheaxialresolutionanddepthoffield(DOF)canbeimprovedbytimegaincompensation(TGC)andmulti-depthmethod.Theresultsindicatethattheproposedsystemcouldachieveover24fpsfor1mmscandistanceand100linesperframe.Inthefuture,thedevelopedsystemispotentialforotherclinicalapplicationssuchasophthalmologyanddermatology.

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简介：他们既不是成绩斐然的明星员工，也不是排名垫底的落后分子；他们胜任本职工作，整体表现尚可，但对于追求金钱和职业发展兴趣不大，一般管理和激励手段对他们无济于事。这个“夹生层”的积极性，如何激发出来？

简介：新年第一期杂志，临近寒假。临近春节。在这喜气祥和的时刻。本刊与同学们共同分享最HGIH的班级PARTY。在你的求学生涯中，总有一些班级PARTY让你HIGH到极致，不吐不快。一份份真挚的生日祝福，透过暖暖的烛光，传递的是温暖；一段段热辣的劲歌热舞，即兴耍宝，让全班同学开怀大笑；一句句“老师，您辛苦了”让人动容!这些最HIGH的班级PARTY故事，会让我们在冬日里内心温暖，也会让我们对春天更加向往!

简介：“我快乐吗？”泰瑞每天都要问自己，而且泰瑞自己每天的答案都是一样。泰瑞觉得自己要被自己逼疯了。枯燥烦闷的工作，老板严厉的脸色，了无希望的前途，让泰瑞似乎患上了“上班恐惧症”。回到家，除了瘫在沙发上看冗长的电视剧，就是呆呆地盯着窗外的大树树叶。泰瑞觉得自己似乎老态龙钟得像退休的老人，可自己实实在在才20多岁。他有些惶恐，自己以后的Ft子是不是每天都这样复制下去，是不是每天都要过这种快要生出霉苔的日子。

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简介：InordertoobtainhigheremissionperformancethanthatofatraditionalM-typecathode,wehavedevelopedanewtypeimpregnateddispensercathode.Thenewcathodeisimpregnatedwithanewactivesubstancewithmolarratioof26BaO·29SrO·8Sc2O3·7CaO·Al2O3.Thispaperintroducestheemissionperformance,surfaceactivematerial,andworkfunctionofthenewcathode.At1100℃B,theDCcurrentdensityandpulsecurrentdensityare30.6±1.0A/cm2and171.6±2.8A/cm2,respectively,2.1and5.4timesofthatofanM-typecathode.Theworkfunctionofthenewcathodeis1.668±0.002eV.HighconcentrationO-Al-Sc-Sr-BaandO-Al-Sc-Baarefoundintheporesandatporeedges,respectively.Bycomparingtheemissionperformancesandsurfacecharacteristicsofas-polishedandas-cleanedcathodes,itisproposedthat,theemissionaroundporeendsformsthemajorpartofthetotalemissionforthenewcathodes.

简介：Laserresistanceandstress-freemirrors,windows,polarizers,andbeamsplittersupto400mm×400mmarerequiredfortheconstructionoftheseriesSGfacilities.Inordertoimprovethecoatingquality,aprogramhasbeeninplaceforthelasttenyears.Forthesmall-aperturepick-offmirror,thelaser-induceddamagethreshold(LIDT)isabove60J/cm2(1064nm,3ns),andthereflectedwavefrontislessthanλ/4(λ=633nm).TheBrewster-anglepolarizingbeamsplitter(Φ50×10mm)showsthebestLIDTresult,upto29.8Jcm2(1064nm,10ns)forap-polarizedwaveinthe2012damagecompetitionoftheXLIVAnnualBoulderDamageSymposium.Forthelarger-aperturemirrorandpolarizer,theLIDTisabove23Jcm2(1064nm,3ns)and14Jcm2(1064nm,3ns),respectively.Thereflectedwavefrontislessthanλ/3(λ=633nm)attheusedangle.

简介：Forthepurposeofachievinghigh-resolutionoptimalsolutionsthispaperproposesanodaldesignvariablebasedadaptivemethodfortopologyoptimizationofcontinuumstructures.Theanalysismesh-independentdensityfield,interpolatedbythenodaldesignvariablesatagivensetofdensitypoints,isadaptivelyrefined/coarsenedaccordingtoacriterionregardingthegray-scalemeasureoflocalregions.Newdensitypointsareaddedintothegrayregionsandredundantonesareremovedfromtheregionsoccupiedbypurelysolid/voidphasesfordecreasingthenumberofdesignvariables.Apenalizationfactoradaptivitytechniqueisemployedtopreventprematureconvergenceoftheoptimizationiterations.Suchanadaptiveschemenotonlyimprovesthestructuralboundarydescriptionquality,butalsoallowsforsufficientfurthertopologicalevolutionofthestructurallayoutinhigheradaptivitylevelsandthusessentiallyenableshigh-resolutionsolutions.Moreover,comparedwiththecasewithuniformlyandfinelydistributeddensitypoints,theproposedadaptivemethodcanachieveahighernumericalefficiencyoftheoptimizationprocess.

简介：NanostructuredtitaniahavebeenintensivelyinvestigatedasanodematerialsofLi-ionbatteriesfortheirexcellenthighrateperformance.ThesizeeffectsofTiO2polymorphs(mainlyrutile,anataseandTiO2-B)ontheirelectrochemicalperformanceandthelatesteffortsinnanoengineeringtitaniaanodesthroughenhancingtheirionicorelectronictransportationorbotharereviewedinthiswork.Wesupposethatmicron-orsubmicronsizedporousstructuresassembledbyTiO2nanoparticles,nanowires/nanotubesornanosheetswithahighpercentageofexposinghighreactivefacetstogetherwithaconductivepercolatingnetworkareidealanodesnotonlyforhighratelithiumstoragebutalsoforhighpackingdensitiesoftheactivematerials.

简介：Permanentmagneticmaterialscapableofoperatingathightemperatureupto500°Chavewidepotentialapplicationsinfieldssuchasaeronautics,space,andelectroniccars.SmCoalloysarecandidatesforhightemperatureapplications,sincetheyhavelargemagnetocrystallineanisotropyfield(6–30T),highCurietemperature(720–920°C),andlargeenergyproduct([200kJám-3)atroomtemperature.However,thehighestservicetemperatureofcommercial2:17typeSmComagnetsisonly300°C,andmanyeffortshavebeendevotedtodevelopnovelhightemperaturepermanentmagnets.ThisreviewfocusesonthedevelopmentofthreekindsofSmCobasedmagnets:2:17typeSmComagnets,nanocrystallineSmComagnets,andnanocompositeSmComagnets.Theoxidationprotection,includingalloyingandsurfacemodification,ofhightemperaturepermanentmagnetsisdiscussedaswell.

简介：大学校园的生活多姿多彩，大学生活的快乐多种多样，有些快乐只能一个人独享，如埋头读书的快乐、独自沉思的快乐、，有些快乐要两个人一起才能获得，如偎依缠绵的快乐、布阵对弈的快乐，但还有一些快乐，要大家一起来，才够high!

简介：Intensiveturbulenceexistsinthewakesofhighspeedtrains,andtheaerodynamicperformanceofthetrailingcarcoulddeterioraterapidlyduetocomplicatedfeaturesofthevorticesinthewakezone.Asaresult,thesafetyandamenityofhighspeedtrainswouldfaceagreatchallenge.Thispaperconsidersmainlythemechanismofvortexformationandevolutioninthetrainflowfield.ArealCRH2modelisstudied,withaleadingcar,amiddlecarandatrailingcarincluded.Di?erentrunningspeedsandcrosswindconditionsareconsidered,andtheapproachesofunsteadyReynold-averagedNavier–Stokes(URANS)anddetachededdysimulation(DES)areutilized,respectively.ResultsrevealthatDEShasbettercapabilityofcapturingsmalleddiescomparedtoURANS.However,forlargeeddies,thee?ectsoftwoapproachesarealmostthesame.Inconditionswithoutcrosswinds,twolargevortexstreetsstretchfromthetrainnoseandinteractstronglywitheachotherinthewakezone.Withthereinforcementoftheground,acomplicatedwakevortexsystemgeneratesandbecomesstrengthenedastherunningspeedincreases.However,thelocationsofflowseparationsonthetrainsurfaceandtheseparationmechanismkeepunchanged.Inconditionswithcrosswinds,threelargevorticesdevelopalongtheleewardsideofthetrain,amongwhichtheweakestonehasnoobviousinfluenceonthewakeflowwhiletheothertwostretchtothetailofthetrainandcombinewiththehelicalvorticesinthetrainwake.Thus,optimizationoftheaerodynamicperformanceofthetrailingcarshouldbeaimingatreducingtheintensityofthewakevortexsystem.

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简介：MesoporousLiFePO4/Ccompositescontaining80wt%ofhighlydispersedLiFePO4nanoparticles(4-6nm)werefabricatedusingbimodalmesoporouscarbon(BMC)ascontinuousconductivenetworks.TheuniqueporestructureofBMCnotonlypromisesgoodparticleconnectivityforLiFePO4,butalsoactsasarigidnano-confinementsupportthatcontrolstheparticlesize.Furthermore,thecapacitieswereinvestigatedrespectivelybasedontheweightofLiFePO4andthewholecomposite.Whencalculatedbasedontheweightofthewholecomposite,itis120mAh·g-1at0.1Cofthehighloadingelectrodeand42mAh·g-1at10Cofthelowloadingelectrode.TheelectrochemicalperformanceshowsthathighLiFePO4loadingbenefitslargetapdensityandcontributestotheenergystorageatlowrates,whiletheelectrodewithlowcontentofLiFePO4displayssuperiorhighrateperformance,whichcanmainlybeduetothesmallparticlesize,gooddispersionandhighutilizationoftheactivematerial,thusleadingtoafastionandelectrondiffusion.

简介：Toimprovetheperformanceoftransmissionbyreducingthenumberoftransmissionandnetworkoverheadofwirelesssingle-hopnetworks,thispaperpresentsahighefficientmultipacketdecodingapproachfornetworkcoding(EMDNC)inwirelessnetworksaccordingtotheideaofencodingpacketswhichcannotbedecodedandarestoredinbufferbyreceivingnodes,thelostpacketscanberecoveredfromtheseencodedpackets.Comparedwiththenetworkcodingwirelessbroadcastingretransmission(NCWBR),EMDNCcanimprovetheefficiencyofdecodingandreducethenumberofretransmissionandtransmissiondelay.SimulationresultsrevealthatEMDNCcaneffectivelyreducethenumberofretransmissionandnetworkoverhead.

简介：Thestructuralpropertiesofjadeiteathighpressures(0.0001-30GPa)areinvestigatedusingplane-wavepseudopotentialdensityfunctionaltheorymethod.Asafunctionofpressure,themonocliniccellparameterswerecalculatedandthecompressibilitycoefficientsare0.0026,0.0023and0.0026GPa-1,respectively.Thebondlength,bondangleanddistortionvariationwerestudiedinordertoobtaintheinformationofpolyhedralcompression.Thepressure-volumeequationofstatewasconsideredinordertoobtainthebulkmodulusK0.ComparisonbetweenthecalculatedK0valuesandtheexperimentaldatasuggestedthatthemodelprovidesreasonableinsightsintocrystallographicandphysicalpropertiesofjadeite.

简介：Pantographsystemofhigh-speedtrainsbecomesignificantsourceofaerodynamicnoisewhentravellingspeedexceeds300km/h.Inthispaper,ahybridmethodofnon-linearacousticsolver(NLAS)andFfowcsWilliams-Hawkings(FW-H)acousticanalogyisusedtopredicttheaerodynamicnoiseofpantographsysteminthisspeedrange.Whenthesimulationmethodisvalidatedbyabenchmarkproblemofflowsaroundacylinderoffinitespan,wecalculatethenearflowfieldandfaracousticfieldsurroundingthepantographsystem.Andthen,thefrequencyspectraandacousticattenuationwithdistanceareanalyzed,showingthatthepantographsystemnoiseisatypicalbroadbandonewithmostacousticpowerrestrictedinthemedium-highfrequencyrangefrom200Hzto5kHz.Theaerodynamicnoiseofpantographsystemsradiatesoutwardsintheformofsphericalwavesinthefarfield.Analysisoftheoverallsoundpressurelevel(OASPL)atdifferentspeedsexhibitsthattheacousticpowergrowsapproximatelyasthe4thpoweroftrainspeed.Thecomparisonofnoisereductioneffectsforfourtypesofpantographcoversdemonstratesthatonlycase1canlessenthetotalnoisebyabout3dBasbafflesonbothsidescanshieldsoundwaveinthespanwisedirection.ThecoversproduceadditionalaerodynamicnoisethemselvesintheotherthreecasesandleadtotheriseofOASPLs.

简介：Thecoherenceisameasurefortheaccuracyoftheinterferometricphase,andthesyntheticapertureradar(SAR)interferometriccoherenceisaffectedbyseveralsourcesofthedecorrelationnoise.ForthecircularSAR(CSAR)imaginggeometry,thesystemresponsefunctionisintheformoftheBesselfunctionwhichbringsahighsidelobe,andthehighsidelobeofCSARwillbeanimportantfactorinfluencingtheinterferometriccoherence.Theeffectofthehighsidelobeonthecoherenceisanalyzedanddeduced.BasedontheinterferometriccharacteristicsoftheslightdifferenceintheviewinganglesandthepotentialpixeloffsetintheinterferometricSAR(InSAR)images,arelationbetweentheradarimpulseresponseandthecoherencelossfunctionisderived.Fromtherelationalmodel,thecoherencelossfunctionduetothehighsidelobeofCSARisthendeduced,andcomparedwiththatoftheconventionalSAR.ItisshownthatthehighsidelobeofCSARfocusingsignalwillseverelyaffectthebaselinedecorrelationandcoregistrationdecorrelation.SimulationresultsconfirmthetheoreticalanalysisandquantitativelyshowthebaselineandcoregistrationdecorrelationdegradationduetothehighsidelobesofCSAR.