简介:MoleculardynamicssimulationusingauniversalforcefieldhasbeenemployedtodeterminethediffusioncoefficientsofO2andNa2SO4vaporintoB2O3andSiCfrom700Kto1273K,respectively.Einsteindiffusionwasobservedina250~300pssimulation.ThediffusioncoefficientfortheO2rangefromabout9.279×10-9cm2/sforB2O3to2.275×10-10cm2/sforSiCataloadingof32moleculespersimulationbox,thatfortheNa2SO4vaporrangefromabout9.888×10-7cm2/sforB2O3to1.837×10-10cm2/sforSiCataloadingof8moleculespersimulationbox.EnvironmentpropertiesofC/SiCcompositewillbeincreasedviatheB2O3preventingthediffusionofO2andNa2SO4vaporintothepyrolyticinterphaseandcarbonfibers.
简介:λ-MnO2waspreparedbycolumnmethodfromnormalspinelLiMn2O4withpurityof99.38%.TheinfluenceofLiMn2O4grainsizeandacidityofleachingsolutiononthelithiumleachingprocesswasstudied.TheresultsshowthattheappropriaterangeofLiMn2O4grainsizewas60-160meshesandtheconcentrationofleachingsolutionHClwas0.1mol·L-1.TheadsorptioncapacityQofλ-MnO2forlithiumincreasedwiththeincreaseofpHandchangedmarkedlyatpH6.0-10.0.Itwas3.80mmol/gatpH12.0.ThedistributioncoefficientsKdofLi+andNa+were3.406×104and2.300respectively,andtheseparationcoefftcientaLiNawas1.481×104atpH6.5.Asaresult,λ-MnO2isahighperformanceion-sievematerialforlithiumion.
简介:Asanodematerialsforlithium-ionbatteries,SiO_2isofgreatinterestbecauseofitshighcapacity,lowcostandenvironmentalaffinity.AfacileapproachhasbeendevelopedtofabricateSiO_2@Chollowspheresbyhydrolysisoftetraethylorthosilicate(TEOS)toformSiO_2shellsonorganicspheretemplatesfollowedbycalcinationsinairtoremovethetemplates,andthentheSiO_2shellsarecoveredbycarbonlayers.ElectronmicroscopyinvestigationsconfirmhollowstructureoftheSiO_2@C.TheSiO_2@ChollowsphereswithdifferentSiO_2contentsdisplaygradualincreaseinspecificcapacitywithdischarge/chargecycling,amongwhichtheSiO_2@CwithSiO_2contentof67wt%exhibitsdischarge/chargecapacitiesof653.4/649.6mAhg~(-1)over160cyclesatcurrentdensityof0.11mAcm~(-2).TheimpedancefittingoftheelectrochemicalimpedancespectroscopyshowsthattheSiO_2@CwithSiO_2contentof67wt%hasthelowestchargetransferresistance,whichindicatesthattheSiO_2@Chollowspheresispromisinganodecandidateforlithium-ionbatteries.
简介:ZrC涂层被低压力在石墨底层上扔有Br的化学蒸汽免职(LPCVD)2-Zr-C3H6-H2-Ar系统。微观结构和ZrC涂层的生长行为上的免职时间的效果被调查。ZrC涂层在一个岛层模式成长了。涂层的形成被ZrC的成核统治在起始20分钟,和快速的成核产生了ZrC的有细密纹理的结构涂层。免职时间什么时候在30min上,涂层的生长被统治由晶体,给安排列的结构。精力散X光检查光谱学证明到锆的碳的臼齿的比率在在ZrC涂层,和X光检查的1:1附近显示出的光电子光谱学ZrC是在涂层的主要阶段,由大约2.5mol%伴随了ZrO2次要的阶段。
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简介:Hydroxyapatite(哈,Ca10(PO4)6(哦)2)涂层被激光cladding技术在纯Ti(TA2)上制作。阶段结构,微观结构,microhardness和激光cladded的电气化学的行为哈在人工的身体液体的涂层被调查。HA涂层主要高度被创作的结果表演结晶哈。过渡的层在之间哈涂层和Ti底层被形成。Microhardness测量显示出逐渐地在过渡的层在TA2底层从150HVmicrohardness增加到600HV,并且由一减少到400HV在列在后面哈涂的层。电气化学的腐蚀测试证明HA涂层与TA2底层相比有更高开的电路潜力,更低的腐蚀水流密度和腐蚀率。
简介:为了降低ε型六硝基六氮杂异伍兹烷(ε-HNIW)的感度,提出了一种以液态CO2作为反溶剂的新的包覆方法,该包覆方法解决了水悬浮法对溶剂的选择局限性大的问题。对ε-HNIW包覆前后进行SEM、XRD和FT-IR分析,研究表明:选用这种新的包覆方法,氟橡胶、ESTANE和EPDM包覆剂能均匀包覆于ε-HNIW的表面;偶极矩-极性大的包覆剂溶剂使ε-HNIW包覆后转变为α-HNIW晶体;随着包覆剂添加量的增加、或系统压力的降低、或温度的升高,ε-HNIW复合颗粒的分散性越差,球形造型粉颗粒度越好。对ε-HNIW包覆前后进行撞击感度测试表明,相同包覆剂添加量情况下,3种包覆剂降低ε-HNIW感度的大小顺序为:ESTANE〉FE26〉EPDM。
简介:Inthepaper,theauthorsanalysetherela-tionshipbetweentheelectricalconductivityσofZrO2andthecontentofdopedstabilizingagentbythePositronAnnihilationTechnique,andexplainthechangetendencyofσwiththecontentofstabilizingagent.Theresearchshowsthat"numberofeffectivevacancy"inmaterialisadecisivefactorcausingchangeofσ.