简介:文章定义了HA-凸函数的概念,给出了HA-凸函数的充要条件及其判定定理,导出了HA-凸函数的Jensen型不等式及其应用.
简介:Thepurposeofthepresentstudywastosynthesizeanewcompositesscaffoldcontainingpoly(γ-benzyl-L-glutamate)modifiedhydroxyapatite/(poly(L-lacticacid))(PBLG-g-HA/PLLA)andtoinvestigatetheirinvitrobehaviouronbonemesenchymalstromalcells(BMSCs).TheresultsdemonstratedthatBMSCproliferationwassignificantlyincreasedonPBLG-g-HA/PLLAscaffoldsafter3and7dayspostseedingwhencomparedtoPLLAandHA/PLLAscaffolds.TheinvitroosteogenicdifferentiationalsofavouredthecompositePBLG-g-HA/PLLAscaffoldswhencomparedtocontrolsbysignificantlyincreasingRunx2,ALPorosteocalcinmRNAexpressionasassessedbyreal-timePCR.TheresultsillustratethepotentialofPBLG-g-HA/PLLAscaffoldsforbonetissueengineeringapplications.AndtheinvivotestingfurtherconfirmsthePBLG-gHA/PLLAscaffolds'potentioalforhealingcriticalbonedefects.
简介:摘要目的探讨丹参酮IIA治疗慢性肺心病急性加重期的疗效观察。方法将118例慢性肺心病急性加重期患者随机分为对照组和治疗组,对照组采用常规基础治疗,给予患者依拉普利治疗,治疗组在对照组基础上给予丹参酮IIA治疗,对比两组患者疗效情况及治疗前后心功能改善情况。结果治疗组患者治疗后总有效率为94.92%,对照组患者治疗后总有效率为81.36%,两组总有效率对比差异有统计学意义(P<0.05);治疗组治疗后RVP、LVEF、Mpvp指标显著优于治疗前及对照组治疗后,且差异有统计学意义(P<0.05)。结论丹参酮IIA治疗慢性肺心病急性加重期的疗效显著,能显著改善患者心功能。
简介:Precipitationresponseofarecentlydevelopedb-typeTi–25Nb–2Mo–4Snalloy(wt%)duringagingwasinvestigatedindetail.Experimentalresultsindicatethatthemetastableωorequilibriumαphasecanformalternativelyevenunderthesameagingcondition,dependingontheconditionpriortotheaging,i.e.,solutiontreatmentorseverecoldrolling.Thisprovides,forthefirsttime,thedirectevidenceforthecompetitionbetweenωandαinagedβ-typeTialloys.Thispeculiaragingresponseisfoundtobecloselyrelatedtohigh-densitydislocationsandgrainboundarieswhichsuppresstheformationofωbutfavortheprecipitationoffineaphase.
简介:TheeffectsofheattreatmentsonthephasetransformationbehaviorofTi49Ni49.5Fe1V0.5andTi48Ni48.5Fe1V2.5alloyswereinvestigated.TheresultsindicatethatthealloyssubjectedtodifferentheattreatmentshaveB2structureatroomtemperature.AllthespecimensexhibitatwostageB2→R→B190martensitictransformationoncooling,butaB190→B2one-stagereversemartensitictransformationonheatingexceptagedA1alloy,whichundergoesanabnormaltwo-stagetransformationuponheating.ThephasetransformationtemperaturesareaffectedbyheattreatmentsandVcontent,whichcanbeattributedtothevariationofthesecond-phaseparticlescontentinthematrix.
简介:Duetolowactivationcharacteristics,desirablehigh-temperaturestrength,goodresistancetoradiationdamageandusablefabricationproperties,vanadium(V)alloysareattractivecandidatestructuralmaterialsforfusionreactors[1].Irradiationinducedhardening/embrittlementatlowtemperatureisamajorproblemforthematerialsapplicationinfusionreactor[2].Inthisstudy,H/Heionswithvariousenergieswereusedtoirradiateapurevanadium(V)andaValloy(V-4Ti)toobtainadamageplateaufromsamplesurfacetothedepthof1.5m,asshowninFig.1[3].Thedetailsofirradiationparameters(energies,fluences)forHandHeionsareshowninTable1.NanoindentationwasperformedtoinvestigatethehardeningbehaviorofV-4TialloyandpureVunderirradiation.
简介:WedevelopasplicingtechnologyofTi:sapphirecrystalsforahigh-energychirpedpulseamplifierlasersystemthatcansuppresstheparasiticlasingtoimprovetheamplificationefficiencycomparedtoalarge-sizesingleTi:sapphirecrystalamplifier.TheoreticalinvestigationsonthecharacteristicsoftheamplifierwithfoursplicingTi:sapphirecrystals,suchasparasitic-lasingsuppressionandamplificationefficiencies,arecarriedout.Somepossibleissuesresultingfromthissplicingtechnology,includingspectralmodulation,stretchingorsplittingofthetemporalprofile,andthesidelobegenerationinthespatialdomain(nearfieldandfarfield),arealsoinvestigated.Moreover,thefeasibilityofthesplicingtechnologyispreliminarilydemonstratedinanexperimentwithasmallsplicingTi:sapphirecrystalsamplifier.ThetemporalprofileandspatialdistributionoftheoutputpulsefromthesplicingTi:sapphirecrystalamplifierarediscussedinrelationtotheoutputpulsefromasingleTi:sapphirecrystalamplifier.
简介:Sn-dopedTiO_2nanoparticleswithhighsurfaceareaof125.7m~2·g~(-1)aresynthesizedviaasimpleone-stephydrothermaimethodandexploredasthecathodecatalystsupportforprotonexchangemembranefuelcells.ThesynthesizedsupportmaterialsarestudiedbyX-raydiffractionanalysis,energydispersiveX-rayspectroscopyandtransmissionelectronmicroscopy.Itisfoundthattheconductivityhasbeengreatlyimprovedbytheadditionof30mol%SnandPtnanoparticlesarewelldispersedonTi_(0.7)Sn_(0.3)O_2supportwithanaveragesizeof2.44run.ElectrochemicalstudiesshowthattheTi_(0.7)Sn_(0.3)O_2nanoparticleshaveexcellentelectrochemicalstabilityunderahighpotentialcomparedtoVulcanXC-72.Theas-synthesizedPt/Ti_(0.7)Sn_(0.3)O_2exhibitshighandstableelectrocatalyticactivityfortheoxygenreductionreaction.ThePt/Ti_(0.7)Sn_(0.3)O_2catalystreservesmostofitselectrochemicallyactivesurfacearea(ECA),anditshalfwavepotentialdifferenceis11mV,whichislowerthanthatofPt/XC-72(36mV)under10hpotentialholdat1.4Vvs.NHE.Inaddition,theECAdegradationofPt/Ti_(0.7)Sn_(0.3)O_2is1.9timeslowerthancommercialPt/XC-72under500potentialcyclesbetween0.6Vand1.2Vvs.NHE.Therefore,theassynthesizedPt/Ti_(0.7)Sn_(0.3)O_2canbeconsideredasapromisingalternativecathode,catalystforprotonexchangemembranefuelcells.
简介:采用电磁悬浮方法,通过原位观察再辉曲线进行过冷Ti-46Al-7Nb亚包晶合金的快速凝固研究,获得的最大过冷度为240K。在一定过冷度下对悬浮的熔体进行铜基底悬淬,进而对凝固合金的微观组织进行分析。超过一定的临界过冷度(ΔT*=205K),凝固模式将从具有包晶转变特征向包晶转变被抑制转化。当熔体初始过冷度ΔT≤ΔT*时,遵循包晶合金的典型凝固规律,β相作为初生相析出,在随后的冷却过程中包晶相α以包晶反应、包晶转变的方式析出。当ΔT〉ΔT*时,β相直接凝固,包晶相α的析出被抑制。包晶反应能否发生取决于包晶相α的孕育时间τP与再辉后熔体完全β相凝固所需的时间tβ的相对大小。当过冷度相差不大时,通过改变凝固过程的冷速,组织中获得β相向α"相的马氏体转变。