简介:Currentliteraturesassumethataconsumer’swillingtopay(WTP)forabundleisequaltothesumofhisorherseparatereservationpricesforthecomponentgoodsandconcludesthatmixedbundlingissuperiortopurecomponentsinamonopolymarket.However,fullmixedbundlingisadiscountconductinordertoattractmoreconsumers,andthepriceofthebundlemustbelowerthanthesumofthepricesoftwoproducts,whichmustbeconsideredinaconsumers’WTPforthebundle.Then,ifconsumers’reservationpricesareheterogeneousandsubjecttotheuniformdistribution,wecandrawoppositeconclusions:FullmixedbundlingisdisadvantageoustofirmswhenStackelbergpricing.Theprofitunderfullmixedbundlingislessthanthatunderpurecomponents.
简介:Aplasmaarcwelding(PAW)-tungsteninertgas(TIG)hybridweldingprocessisproposed.AndthispaperinvestigatedthemicrostructureandpropertiesofpurenickelN6jointsbyPAW-TIGhybridwelding.ComparedwiththeconventionalPAWmethod,thecharacteristicofPAW-TIGweldingprocessisthatthereisnointeractionbetweenthetwoarcs.TheadditionofTIGcanenhancetheintrinsichigh-efficiencypeculiarityandthestabilityofthekeyholestatusofPAW.ThejointsmadeusingPAWandPAW-TIG,respectively,weresubjectedtomicrostructuralevaluationsandtensiletestingsoastoanalyzetheeffectofTIGarcenergyonthemicrostructureandmechanicalpropertiesofthesejoints.Theresultsofthisinvestigationindicatethatsignificantgraincoarseningwasobservedintheweldmetal(WM)andheataffectedzone(HAZ)anditisfoundthattheextentofgraincoarseningincreasedwiththeadditionofTIGarc.Andthemicrostructureinhybridjoint,withwiderweldwidthandthesmoothsurface,iscoarserthaninPAWjoint.Furthermore,themicrohardnessandultimatetensilestrength(UTS)ofhybridjointisslightlylowerthanthatofPAWjoint.ThefractographobservationshowsthatthefracturingmechanismofPAWjointsductile,whilethehybridweldingjointsexistsasbrittle-ductilefracturemode.Theoutcomeofthisworkshowsthatintheconditionofsamedepositedrate,TIGarcpost-weldheattreatmentcanimprovetheweldingefficiencyandweldingspeed.TheproposedPAW-TIGhybridweldingprocessisdemonstratedtobesuitableforweldingnickelanditsalloysinindustryapplication.
简介:完全经肛全直肠系膜切除术(pure-TaTME)是一种真正符合微创发展理念的手术。从手术切口而言,微创发展追求的极致就是消除切口,即经自然腔道完成体腔内手术(naturalorificetransluminalendoscopicsurgery,NOTES)。完全经肛完成直肠全系膜切除术不仅符合NOTES的概念,而且越来越多的文献表明经肛的中低位直肠癌TME手术中,远端切缘、环周切缘、标本完整性等指标较经腹手术有一定优势。随着技术的发展和成熟,此种手术方式可能会成为经典的直肠癌根治性手术方式之一。
简介:Weprovidethefirstdemonstrationofpureredemissioninthevisiblelightregionviathree-photonexcitationinmonodisperseNa_3ZrF_7:Ernanoparticles(NPs)byusingalaseroperatinginthetelecommunicationband.NPsof~22nmindiameteraresynthesizedat260°Cbythethermaldecompositionmethod.TheexperimentalresultsrevealthattheNa_3ZrF_7:ErNPsexhibitpureredemissioninthevisibleregionunder1480nmlaserexcitation,andtheemissionintensityissignificantlyinfluencedbytheEr~(3+)ionconcentration.Thedecaytimesofthe~4S_(3∕2)→~4F_(15∕2)and~4F_(9∕2)→~4F_(15∕2)transitionsoftheEr~(3+)ionsat540and655nm,respectively,arereducedbyincreasingtheEr~(3+)ionconcentrationintheNa_3ZrF_7:ErNPs.Thesuppressedemissionintensityresultfromthedefect-relatedquenchingeffect:whentrivalentEr~(3+)ionsreplactetravalentZr~(4+)ions,extraNationsandFvacanciesareformedtore-balancethechargeintheNa_3ZrF_7matrix.TheemissioncoloroftheNa_3ZrF_7:ErNPsisrelatedtothecrossrelaxationbetweenEr~(3+)ions.Theseresultsprovideanimportantsteptowardmoreeffectivebiologicalimagingandphotodynamictherapybyminimizingthescatteringoftheexcitationlightandincreasingthepenetrationdepth.
简介:本文以2011~2015年沪深A股农业上市公司为样本,通过综合功效系数得分XS划分企业财务风险的高低,然后采用二分类Logistic回归模型对农业上市公司治理结构的财务风险进行实证研究。研究结果表明,在农业上市公司中,股权集中度、国有控股、两职合一能抑制财务风险;股权制衡度、董事会规模、独立董事比例、监事会规模会扩大财务风险;董事会会议次数、监事会会议次数、高管人员持股比例、高管人员薪酬对财务风险没有显著影响。