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简介：用单辊甩带法制备了不含高生物毒性元素的Ti60Zr10Ta15Si15非晶薄带,并在高于其晶化开始温度的不同温度下对该非晶薄带进行了真空退火,研究了该非晶薄带在磷酸盐缓冲溶液（PBS）中的电化学腐蚀行为及热处理对其显微组织及其电化学行为的影响。结果表明,用单辊甩带法制备的Ti60Zr10Ta15Si15金属薄带为完全的非晶态结构,其玻璃转变温度和晶化开始温度分别为759K和833K,经过878K真空热处理后,薄带发生了部分晶化,在非晶的基底上析出了Ti相;经过938K热处理后,薄带发生了完全晶化,晶化相主要由Ti、Si3Ta5和SiZr以及TiSi组成。动电位极化测试表明,该非晶合金在PBS溶液中可表现出较为优异的耐蚀性能,部分晶化可进一步提高该合金的耐蚀性能,而完全晶化的合金抗腐蚀性能明显下降。

简介：有0.2–的直径的新宏观规模的SBA-15范围；0.5公里被sol–准备；胶化方法，tetrabutylorthosilicate(TBOS)在被用作硅来源和triblock共聚物和polyoxyethylene辛基酚醚(OP-10)(P123)被用作模板。结果球形的样品被XRD描绘，N2adsorption–；解吸附作用，TEM和SEM方法。结果证明SBA-15宏范围的内部结构有宏多孔的隧道(0.5μ；m)并且我酣睡的骨骼(4–；5nm)。有层次毛孔结构的这些SBA-15宏范围为Emodin分子表明高吸收能力。

简介：Atwo-dimensionalsteadyReynolds-averagedNavier–Stokes(RANS)equationwassolvedtoinvestigatetheeffectsofaGurneyflaponSFYT15thickairfoilaerodynamicperformance.Thisairfoilwasdesignedforflightvehicleoperatingat20kmaltitudewithfreestreamvelocityof25m/s.Thechordlength(C)is5mandtheReynoldsnumberbasedonchordlengthisRe=7.76×105.Gurneyflapswiththeheightsrangingfrom0.25%Cto3%Cwereinvestigated.Theshearstresstransport(SST)k-ωturbulencemodelwasusedtosimulatetheflowstructurearoundtheairfoil.ItisshowedthatGurneyflapcanenhancenotonlytheprestallliftbutalsolift-to-dragratioinacertainrangeofanglesofattack.Specially,atcruiseangleofattack(α=3°),Gurneyflapwith0.5%Cheightcanincreaselift-to-dragratioby2.7%,andliftcoefficientby12.9%,respectively.Furthermore,thesurfacepressuredistribution,streamlinesandtrailing-edgeflowstructurearoundtheairfoilareillustrated,whicharehelpfultounderstandthemechanismsofGurneyflaponairfoilaerodynamicperformance.Moreover,itisfoundthattheincreaseofairfoildragwithGurneyflapcanbeattributedtotheincreaseofpressuredragbetweenthewindwardandtheleewardsidesofGurneyflapitself.

简介：《数学课程标准》要求学生所掌握的空间与图形内容如下：能够借助不同的方法探索几何对象的有关性质；能够使用不同的方式表达几何对象的大小、位置与特征；能够在头脑里构建几何对象，进行几何图形的分解与组合，能够对某些图形进行简单的变换；能够借助数学证明的方法确认数学命题的正确性。图形与证明是空间与图形的核心内容之一，课标要求学生掌握基本的图形基础知识与基本技能；了解证明的含义，掌握证明的方法，体会证明的过程；能把所学的公理、定理和基本事实正确运用到证明的过程中，在合情推理的基础上发展初步的演绎推理能力；初步通过观察、实验、归纳、类比、推测获得数学猜想，体验数学活动充满着探索性和创造性，感受证明的必要性、证明过程的严谨性及结论的稳定性，它贯穿在整个几何知识的学习及运用之中．

简介：Asanimportantmulti-functionalmaterialappliedinsurfaceacousticwavedevices,opticalcommunications,laserandoptoelectronicsduetoitsgoodphotoelectricandpiezoelectricproperties,lithiumtantalate(LiTaO3)hasdrawnextensiveinterests[1].NumerousphysicalpropertiesofLiTaO3,suchasacoustical,electronicstructures,opticalpropertiesandeffectivemass,thermodynamicproperties,havebeenreportedinseveralpapers.Pointdefectswillaffecttheelectronicstructurewhichshouldberesponsibleformanyphysicalproperties,especiallyopticalproperties.

简介：Fieldemissionoccurredinsuperconductingradio-frequency(SRF)cavitiesisthemajorobstacleoftheacceleratorsoperatingathighgradient,whichpartlycausedbytheinnersurfacecontamination,suchasthehydrocarbonsandtheabsorbedresidualgas.Theplasmaprocessingcanbeaneffectivemethodtosolvethefieldemissionissues.Thepropertiesoflowtemperatureglowdischarge,whichwasargonplasmawiththechemicallyreactiveoxygen,wereinvestigatedfortheSRFcavitiesusedforCADSproject.

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简介：它被Bouchet推测承认的每张bidirected图一没什么地方--零k流动将承认一没什么地方--零6流动。当6被216代替时，他证明conjecture是真的。Zyka与6改进了结果在30代替了。徐和张证明conjecture为6-edge-connected图是真的。并且为证明的4-edge-connected图，Raspaud和朱，它与6是真的在4代替了。在这份报纸，我们证明Bouchets推测与6是真的为3-edge-connected图在15代替了。

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简介：ThispaperstudiestheequilibriumgeometriesandelectronicpropertiesofBenandBenLiclusters,upton=15,byusingdensity-functionaltheory(DFT)atB3LYP/6-31G(d)level.Thelowest-energystructuresofBenandBenLiclustersweredetermined.Theresultsindicatethatasinglelithiumimpurityenhancesthestabilityandchemicalreactivityoftheberylliumclusters.Itfindsthatthegeometriesofthehostclusterschangesignificantlyaftertheadditionofthelithiumatomforn≥8.Thelithiumimpuritypreferstobeontheperipheryofberylliumclusters,andoccupiesvertexsites.BothBe4Li,Be9Li,andBe13Liwerefoundtobeparticularlystablewithhigheraveragebindingenergy,localpeaksofsecond-orderenergydifferenceandfragmentationenergies.ForalltheBenLiclustersstudied,wefoundchargetransfersfromtheLitoBesiteandco-existenceofcovalentandmetallicbondingcharacteristics.更多还原

简介：Veryhighcyclefatigue(VHCF)propertiesofalowtemperaturetemperingbearingsteelGCr15withsmoothandhole-defectspecimensarestudiedbyemployingarotarybendingtestmachinewithfrequencyof52.5Hz.Bothsmoothandhole-defectspecimensbreakinVHCFregimewithsomedifferenceinfatiguecrackinitiation.Forsmoothspecimens,afinegranulararea(FGA)isobservednearthegrainboundaryinthefracturesurfaceofthespecimensbrokenafter10~7cycles.ButnoFGAisobservedinthehole-defectspecimensbrokeninVHCFregime,andtheVHCFcrackdoesnotinitiatefromthesmallholeatthesurfaceasitdoesatloworhighcyclefatigueregime.InternalstressisemployedtoexplaintheVHCFbehaviorofthesetwotypesofspecimens.Atlast,anadvanceddislocationmodelbasedonTanakaandMuramodelisproposedtoillustratetheinternalstressprocessandtopredictfatiguecrackinitiationlifewithFGAobservedinthefractureregion.

简介：2017年7月14—17日，由全国大学生数学建模竞赛组委会、中国工业与应用数学学会数学模型专业委员会和教育工作委员会共同主办，全国大学生数学建模竞赛山东赛区组委会和烟台大学共同承办的第15届全国数学建模教学和应用会议将在山东省烟台市举行。

简介：<正>二次函数在中考中所占比例较大,它可以以单独形式命题,也可以与其他知识(如一次函数、反比例函数、方程、不等式或圆、多边形等)进行综合命题,经综合后往往难度较大,还可以将其与生活实际联系,命出阅读理解、开放探索、应用等类型的难度稍底的新型试

简介：Ithasbeenproposedthatfusionreactionsbetweenneutron-richlightnuclei,forexample24C,24Oand28Ne,maycontributetoachievingtheignitiontemperatureforexplosivecarbonburningprocessduringsuperbusrsts[1,2].Studiesoffusionreactionsinvolvingneutron-richnucleiarebeyondordinaryexperimentaltechniques,sincetheintensityofradioactivebeambecomelowforthesemeasurements[3].TheactivetargettechniqueusingTPC(TimeProjectionChamber),withpropertiesofmulti-sampling,highefficiencyandlowbackground,isasuitablesolutiontotheproblem.

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简介：Phasebehaviorofbinarysystemofbromobenzene-chlorobenzene(C6H_5Br-C_6H_5Cl)confinedinSBA-15andMCM-41(porediameter8nm,3.8nm,respectively)hasbeeninvestigatedbymeansofdifferentialscanningcalorimetry(DSC).PhasediagramofC_6H_5Br-C_6H_5ClsystemconfinedinSBA-15isatypeofthecompletemisciblebothinliquidandsolidstate,thesamephasebehaviorasthebulksystem.However,thephasediagramcomprisesonlyoneboundaryline,whichisshifteddown22-36Kwithrespecttothebulksystem.C_6H_5Br,C_6H_5ClorthemixturewithinnanoporesofMCM-41isnonfreezing.ThedifferentphasebehaviorofthesystemconfinedinSBA-15andMCM-41isthoughtmainlyduetotherelativesizeofporetomolecule.

简介：Themesonproductioninnucleon-nucleoncollisionsnearthresholdhasthepotentialtogaininformationonhadronpropertiesandalsoplaysanimportantroleinexploringthebaryonspectroscopy[1].Inrecentyears,theexperimentaldatabaseonthereactionofpp!ppK+Knearthresholdhasbeenexpandedsignificantly.Inadditiontothemeasurementsofthetotalanddifferentialcrosssections,belowthethresholdoftheproductionofthe?meson,performedexperimentallywithCOSY-11andANKEdetectorsatthecoolersynchrotronCOSYinGermany,invariantmassdistributionsofvarioussubsystemshavebeenobtainedatlowenergies.Unlikeabovethethresholdoftheproductionofthe?meson,inthelowenergyregion,wedonotneedtoseparatethenon-?fromthe?contribution,andduetothefactthatthedatawerespreadoverawiderangeofK+K??invariantmasses,ithasaspecialadvantagetoinvestigatethescalarmesonsa0(980)$andf0(980)whicharedynamicallygeneratedfromtheinteractionsofK￣K,ππ,andπηtreatedascoupledchannelsinI=0andI=1,respectively.BothofthemcouplestronglytotheK￣Kchannel.

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