简介:本文采用磁粉、X射线、CT和超声等无损检测和金相分析等方法对40CrNi2Si2,MoVA钢制零件的磁痕显示进行了系统分析。研究认为,40CrNi2Si2MoVA钢制零件的磁痕显示为显微成分沿变形方向偏析导致的马氏体转变点Ms差异所致。显微成分偏析是钢锭结晶过程中不可避免的,但可通过优化熔炼工艺参数降低显微偏析的程度。本文还分析了四种磁痕显示的类型及其判别方法。
简介:Si_3N_4-Si_2N_2Ocomposites被液相sintering(LPS)与非结晶的缩放nano的氮化矽粉末制作。Si_2N_2O阶段被in-situreaction2Si_3N_4(s)+1.5O_2(g)=3Si_2N_2O+N_2(g)产生直到在体积的60percent的Si_2N_2O阶段的内容在1650t的sintering温度被获得并且当sintering温度增加了或减少时,减少了,显示反应是可逆的。集体损失,相对密度和平均谷物尺寸与增加sintering温度增加了。当sintering温度在1700degC下面时,Theaverage谷物尺寸是不到500nm。Thesintering过程包含复杂结晶化和阶段转变:非结晶的氮化矽->equiaxialalpha-Si_3N_4->equiaxial->Si_3N_4->杆--相似Si_2N_2O->像针的beta-Si_3N_4。小回合--塑造的beta-Si_3N_4粒子在Si_2N_2O谷物被骗诱,界定差错的高密度位于在1650degC的sintering温度的Si_2N_2O谷物的中间。坚韧在1600degCto7.2MPa从3.5Mpa中心点m~(1/2)增加了在1800degC的中心点m~(1/2)。坚硬在1600degC象21.5GPa(Vickers)一样高。
简介:Aneffectivedispersion-strengtheningphaseinAl-8Fe-2Mo-2Zr-2Nd-0.7Ti-1.6SialloywasidentifiedtobeanagedprecipitatephasewithpossiblechemicalstoichiometryofAl20(Ti,Mo)2Ndandfcccrystalstructurewithao=1.455nm.ThestructurewasdeterminedtobeFm3mspacegroup.
简介:AnO'-Sialon-Al2O3compositerefractorywaspreparedbyinsitureactionofSi3N4-ZrSiO4-Al2O3mixturewithfusedaluminaaggregates.Densification,insitureactionprocedureandmicrostructureofthematerialwereinvestigatedbymeansofX-raydiffraction,opticalandscanningelectronicmicroscopesandEDAX.
简介:做Si的Ge(2)sb(2)Te(5)电影被dc劈啪作响magnetronco与Ge2Sb2Te5和Si目标准备了。在在两结晶化温度和阶段转变温度fromface-centred-cubic(fcc)的增加的Te(5)电影结果分阶段执行到的Ge(2)sb(2)的Si的增加六角形(十六进制)阶段。Ge2Sb2Te5电影的抵抗力显示出重要增加,Si做。当在这部电影做Si的11.8at.%时,在退火的460度C以后的抵抗力与undopedGe2Sb2Te5电影相比从64~99终止从1~11m终止(.)厘米和动态抵抗增加增加。这对写阶段变化随机存取记忆的当前的减小很有用。
简介:Usingtransganglionicdegenerativemethed,weinvestigatedtheprimaryafferentinformationofacupointsofQuanliao(SI18)andShibai(ST2).Theresultsshowedthatthelargeamountsofdegenerativefiberscouldbefoundbilaterallyintrigeminalspinalnucleusanditstract,trigeminalprincipalsensorynucleus,trigeminalmesencephalicnucleusandsomedegenerationscouldbeobservedipsilaterallyinsolitarytractanditsnucleus,medullarylateralreticularnucleus,giganto-cellularreticularnucleusandnucleusraphemagnusfollowingtransectionofinfraorbitalnerve.Averymoderatedegenerativefiberscouldbeidentifedinipsilateralaccessoryspinalnucleusandspinalreticu-larnucleus.Afewdegenerativefiberswereseenonthecontralateralmagnocellularpartofcaudatepartoftrigeminalspinalnucleusbypassingthroughtheposteriorcommissureofcanaliscentralis.TheseresultssuggestthattheprimaryinformationofacupointsofQuanliaoandShibaicouldbetrans-mitteredintotheabovestruc
简介:AninitialstructuredesignofMMI1×8opticalpowersplittersisreported.ThewaveguidematerialisSi-basedSiO2Ge-dopedanddepositedbyPECVDmethod.Embeddedstripstructureisimpliedinthesectiondesign.ByusingBPM-CAD,afavorableresultisobtainedthatthisdevicehasasounduniformityandfairlylowloss.Meanwhile,simulationsofdesignswithcertainchangedparametersisalsoimplementedforabetterdesignconfiguration.
简介:二次根式(a~2)~(1|2)和((a~2)~(1|2))有什么区别吗?主要表现在下面三个方面:1.读法不同.(a~2)~(1|2)读作根号a的平方,而((a~2)~(1|2))读作括号根号a括号的平方.2.表示的意义不同.(a~2)~(1|2)是求a~2。的算术平方根.((a~2)~(1|2))求的是a的算术平方根的平方.一个表示求一
简介:Anultrahighvacuumchemicalvapordeposition(UHV/CVD)systemisintroduced.SiGealloysandSiGe/Simultiplequantumwells(MQWs)havebeengrownbycold-wallUHV/CVDusingdisilane(Si2H6)andgermane(GeH4)asthereactantgasesonSi(100)substrates.ThegrowthrateandGecontentsinSiGealloysarestudiedatdifferenttemperatureanddifferentgasflow.ThegrowthrateofSiGealloyisdecreasedwiththeincreaseofGeH4flowathightemperature.X-raydiffractionmeasurementshowsthatSiGe/SiMQWshavegoodcrystallinity,sharpinterfaceanduniformity.Nodislocationisfoundintheobservationoftransmissionelectronmicroscopy(TEM)ofSiGe/SiMQWs.TheaveragedeviationofthethicknessandthefractionofGeinsingleSiGealloysampleare3.31%and2.01%,respectively.
简介:Twonewdicyanamidecoordinationpolymers,{Mn(dmpz)[N(CN)2]2}2(1)and{Cu(dmpz)[N(CN)2]2}2(2)(dmpz=3,5-dimethylpyrazole),weresynthesizedandcharacterizedbysinglecrystalX-raydiffractionanalysisandIRspectroscopy.In1and2themetalionshavetwodifferentcoordinationmodes,whereoneiscoordinatedtofourdicyanamideanionsandtwomonodentatedmpzmoleculestoformaslightlydistortedoctahedralgeometry,whiletheotheradoptsoctahedralgeometry,surroundedbyfournitrileNatomsandtwoamideNatomsofthedicyanamideanions.Bothcomplexescontaintwoalternatingchainsthatareparalleltoeachother.
简介:在本期的“课例大家评”中,我们刊登了同一课题下的6篇课例供大家点评.2001年第4期,我刊登出了“直线方程的一般形式(第一课时)”课例的征稿启事.截止4月30日,我们收到课例来稿百余篇.这6篇课例就是从这些应征稿件中遴选出来的.为了便于大家点评,我们将6篇课例按学生学习状况的优、中、差分为三组,每组有2篇课例.在撰写点评稿时,您可以对6篇课例进行总评,也可以就学生学习状况相当的两篇课例进行评析,还可以对某一课例做单独的评议.总之,点评的内容应相对集中,以便于编者对稿件进行选择和组构.文稿字数以1000字左右为宜,截稿日期为9月10日.投稿时请在信封左下方注明“课例大家评”字样.欢迎广大数学教师和教研工作者积极参与本次“课例大家评”活动,我们将以较大篇幅集中发表观点新颖、论述深刻、对教学具有较强启发性的优秀来稿.在此,我们还特别对提供“直线方程的一般形式”课例的所有老师表示衷心的感谢.
简介:ThecrystalstructureofDi-nitratobis(ethylcaprolactam)uranyl(Ⅱ)UO2[CH2(CH2)4CONC2H5]2(NO3)2wasestablishedbyasingle-crystalX-raydiffractionstudy.Itistriclinie,spacegroupP1,witha=7.171(2),b=8.655(3),c=10.182(5)A,α=78.27(3),β=70.63(3),γ=81.76(3)°,V=581.7(4)A3,Z=l,Dc=1.94g.cm-3.FinalRvalueis0.0218.Theresultrevealsthaturanylioniscoordinatedtosixoxygenatoms,twoofthemarefromtwocarbonylgroupsofethylcaprolactamandtheotherfourarefromtwonitrategroups.