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简介：Si3N4/TiCnanocompositeceramicshavebeenfabricatedbyhotpressingtechniquewithAl2O3andY2O3asadditives.TheresultsshowedthatwelldispersedcompositepowderwascarriedoutbyaddingdispersantandadjustingpHvaluesofsuspensions.RemarkableincreaseinflexuralstrengthatroomtemperatureswasobtainedbyaddingnanoparticlesinSi3N4matrixwith10%(wtpct)ofnano-Si3N4and15%ofnano-TiC.Theflexuralstrength,fracturetoughnessandhardnesswere1025MPa,7.5MPa·1/2and15.6GPa,respectively.Themicrostructuresofmaterialswereanalyzedbyscanningelectronmicroscopy(SEM)andtransmissionelectronmicroscopy(TEM),whichindicatedthatTiCnanoparticlesdistributeinthematrixandatthegrainboundaries.Accordingtothefractureform,lowcontentsofnanoparticlescouldrefinematrixgrainsandleadtothecrackdeflectionaswellascrackpinning.Themultiplexmicrostructurewasformedbymixingnano-Si3N4particles.Thecracktrajectoriesexhibitedcrackdeflection,rod-likegrainbridgingandpull-out.

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简介：ThemagnesiabasedcurablespecimenswithdifferentSi3N4contentswerecastedusingsinteredmagnesite(w(MgO)=95%)asstartingmaterial,SiO2micro-powderasbinder,0.3%,4%and5%β-Si3N4powderreplacingtheequaladditionofmagnesiapowderrespectively.Theslagresistancetestwascarriedoutat1550℃for3husingBaosteeltundishslagandstaticcruciblemethod.Theresultindicatesthat:introducingSi3N4couldobviouslyimprovetheslagresistanceofMgObasedcastable,whichincreasedwithincreasingSi3N4.DenseSiO2sinteredlayerformedonthesurfaceofmagnesiabasedcastablebecauseoftheoxidationofSi3N4addition,whichcanpreventthefurtherslagpenetration.Inthedeepinnerofcastable,thepartial-pressureofoxygenwasverylow,soSi3N4canexiststably.Meanwhileinreducingatmosphere,Si3N4washardtobesintered,whichresultedinthelooseinteriorstructureofMgObasedcastable.

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简介：Amorphoussilicon(a-Si),nanocrystallinesilicon(nc-Si)andhydrogenatednanocrys-tallinesilicon(nc-Si:H)filmswerefabricatedbyusingchemicalvapordeposition(CVD)system.Thea-Siandnc-Sithinfilmswereirradiatedwith94MeVXe-ionsatfluencesof1.0×1011ions/cm-2,1.0×1012ions/cm-2and1.0×1013ions/cm-2atroomtemperature(RT).Thenc-Si:Hfilmswereirradiatedwith9MeVXe-ionsat1.0×1012Xe/cm-2,1.0×1013Xe/cm-2and1.0×1014Xe/cm-2atRT.Forcomparison,mono-crystallinesilicon(c-Si)sampleswerealsoirradiatedatRTwith94MeVXe-ions.AllsampleswereanalyzedbyusinganUV/VIS/NIRspectrometerandanX-raypowderdiffractometer.Variationsoftheopticalband-gap(Eg)andgrainsize(D)versustheirradiationfluencewereinvestigatedsystematically.Theobtainedresultsshowedthattheopticalband-gapsandgrainsizeofthethinfilmschangeddramaticallywhereasnoobservablechangewasfoundinc-SisamplesafterXe-ionirradiation.Possiblemechanismunderlyingthemodificationofsiliconthinfilmswasbrieflydiscussed.

简介：介绍了Fe3Si的一些基本特性及Fe3Si薄膜的几种主要制备方法,重点介绍了分子束外延法中不同类型衬底、温度对Fe3Si薄膜形成的影响,并且分析了各种制备方法中的一些重要参数对薄膜结构及性质的影响。随着Fe3Si薄膜制备工艺的不断完善,Fe3Si薄膜将会成为一种性能优秀的自旋电子器件。

简介：Siliconnanoconearrayswithmetalsilicide(FeandCr)-enrichedapexesarefabricatedonSi(100)substratebytheAr+ionbombardmentmethod.Thenanoconearraysshowexcellentfieldemissionproperties.Ahighcurrentdensity(J)of～0.33mA/cm2underafieldof～3V/μm,averylowturn-onfieldof～1.4V/μm,andaverylargeenhancementfactorof～9466arealsoobtained.TheemissionJofSinanoconearraysremainsextremelystableforlongperiodsoftime(24h).

简介：Pure-Ge/Sishortperiodsuperlattice(SPS)grownbygassourceMBE(GSMBE)isstudiedbyphotoluminescencespectroscopyandRamanscatteringspectroscopy.AnabnormalbandinphotoluminescenceisfoundinanintermediaterangeofLsibetween1.9nm-2.9nmforsampleswithLgefixedat1.5ml.Incontrasttoapure-Ge/Siquantumwell,theenergyofthebandshowsred-shiftasLsiincreases.RamanscatteringshowsthatSi-SivibrationrelatedRamanshiftreachesaminimumforsampleswithstrongestPLintensityoftheabnormalband.Itisthereforeconcludedthattheabnormalbandisrelatedwithstrainrelaxationprocess.

简介：TherearetwotpyesofphasetransformationsinFe-MnandFe-Mn-Sialloyswhenthetemperatureisdecreased,γ(fcc)→ε(hcp)martensitictransformation(MT)andparamagnetic-antiferromagnetictransition(AMT)ofγphase.Fromthethermodynamicpointofview,theformerusuallyappearsinaslightlyhighertemperaturerangethanthelatterbecauseifisgenerallyacceptedthatthemagnetictansitionhasasuppressingeffectonthethermallyinducedεmartensite(Satoetal.,1984.,BogachevandZvigintzeva,1976;Murakamietal.,1987:Yangetal.,1992)GartsteinandRobinkin(1979)eventhoughtthattheγ-εtransformationshouldbeterminatedbelowNeeltemperature(TN)duetothedecreaseoffreeenergyarisingfromtheAMTofγphase.However,someexperimentalresultshaeindicatedtheformationofεphasebelowT(LiandWayman,1994:Fujimori.1966).Inthepresentwert.thebehavorofγ-εtransformationbelowTNwasfurtherinvestigatedbyclectricalresistancemeasurements.

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简介：等离子喷涂液相合成法是一项生产纳米材料的新技术，这项新技术利用工业上的等离子体喷涂系统在大气环境中生产纳米粉末，用简单的平行电极静电收集器可进行粉末的收集。研究表明利用等离子体的高温、高温度梯度的特性，可使钛酸丁酯发生裂解而制得纳米TiO2粉末。等离子喷涂合成法是一个简单的工艺过程，

简介：送检地下水水型为HCO3^--SO4^2--Ca^2＋-（Mg^2＋）型，酸碱度为中性、水介质属氧化型（Eh=640my）、低矿化，样品水中各项水质分析项目为，K^＋＋Na^＋，Ca^2＋，Mg^2＋，Fe^3＋，Cl^-，SO4^2-，HCO3^-，CO3^2-，NO3^-，OH^-；所对应分析值为0．670×10^-3，1．200×10^-3，0．400×10^-3，1．79×10^-3，0．036×10^-3，0．88×10^-3，2．074×10^-3，10^-5.863，0．035×10^-3，10^-7.07。

简介：根据FFF02型防毒服改进研制要求，试制薄型阻燃炭布，在保持FFF02型防毒服内层材料115型阻燃炭布各项基本性能的基础上，采用新的原材料、新的喷炭配方和工艺，综合提高炭布的使用性能．通过试验，研究高吸附性能活性炭、黏合剂、炭浆配方以及阻燃绒布等材料对炭布性能的影响，为FFF02型防毒服改进研制打下良好的基础．

简介：本文记叙了2005年10月02日福州洪水对流体的干扰及其分析。

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简介：空气中的S0-2气体对丝织品文物有一定的危害作用。课题分别试验了各种丝织品试样在50μmol／mol的SO2气体下不同时间的影响变化。通过色差分析，红外分析，氨基酸分析及XRD分析对丝织品进行表征，得到了40℃下50天的干热老化丝织品试样在50μmol／mol的S0-2气体下，随着试验时间的延长，其色差变化最大。经S02气体处理的丝织品试样的氨基酸成分发生改变，结晶度也变大，老化程度加大。本研究结果可为保存和保护丝织品文物提供依据。