简介:研究KTiOAsO4晶体的生长缺陷,对于改善它的性能和应用前景,有很大的意义。本文利用化学腐蚀光学显微术和同步辐射X射线形貌术研究了KTiOAsO4晶体的缺陷,实验结果表明,两种腐蚀剂对于显示KTA晶体的表面缺陷效果显著,KTA晶体中主要的缺陷有铁电畴、生长层、扇形界、位错和包裹物。讨论了这些缺陷形成的原因。
简介:LiNdP4O12(LNP)晶体是一种新型的激光材料。本文报道了用同步辐射X射线白光形貌术和光学显微法研究由助熔剂籽晶旋转法生长的LNP晶体的生长缺陷,观察到了圆形生长台阶及精细的系列台阶结构,对晶体中的包裹物和位错缺陷等进行了详细的观察描述,还发现了一种比较奇特的腐蚀沟槽,分析了这种腐蚀沟槽的形成机理及各种缺陷的成因和克服办法。
简介:报道了用同步辐射X射线白光形貌术和光学显微法研究由助熔剂籽晶旋转法生长的LNP晶体的生长缺陷。本文除对晶体中的包裹物和位错缺陷等进行了详细观察描述外,还发现了一种比较奇特的腐蚀沟槽。最后分析了这些缺陷的成因和克服办法。
简介:Insituwhite-beamsynchrotronradiationtopographicobservationsunderanelectricfieldhavebeenmadeontheKTiOPO4(KTP)familyofcrystals.Theinvestigationshowsastrongenhancementofdiffractedintensityforhklreflections(l≠0)andtopographiccontrastintheformoffinestriationswhentheexternalelectricfieldisparalleltothepolaraxis.Severalkkindsofdopedandundopedsampleswithvariousgrown-indefects,suchasdomainboundaries.growthstriations,growth-sectorboundaries.dislocations.etc.,havebeenstudiedindetail.Theresultssuggestthatthesedefectshaveverylittleeffectonthefield-inducedstriations,ItisbelievedthatthemovementofK^+ionsdrivenbytheelectricfieldleadstoalocalaccumulationofchargesandalatticedistortion.Thestronlyanisotropicconductivityisagoverningfactorintheexplanationofthefield-relatedphenomenainthiskindofquasi-one-dimensionalconductor.
简介:Anewtwo-dimensionalstructuremodulationalongc-andb-axeshasbeendiscoveredinsuperconductingsinglecrystalsofBi2.13Sr1.87CuO6+δ(Bi2201)byx-rayscattering.Suchmodulationstructuredoesnotexistinnon-superconductingBi2201singlecrystals.Butinsteadlatticedistortionsareobservedinthea-b-plane.Thisphenomenonmayindicatethatbothstrainrelaxationandchargemodulationinthea-b-planeareimportanttotheoccurrenceofsuperconductivityinthecopperoxides.
简介:Attheambienttemperatureandpressureaglowdischargeplasmawasusedasanewapproachforthecouplingofmethanewiththenewly-developedrotarymultidentatehelixelectrode.Inthepresenceofhydrogen,theeffectsoftheinputpeakvoltagesandgasflowratesonmethaneconversion,C_2singlepassyieldandselectivitywereinvestigated,andthentheresultswerecomparedwiththosefromthethree-discmultidentateelectrode.Thisdemonstrated,onanexperimentalscale,thattherotarymultidentatehelixelectrodewasbetterthanthemultidentatethree-discelectrodeastherewaslittleaccumulationofcoke,andtheC_2yieldperpasswas69.85%andC_2selectivityover99.14%with70.46%methaneconversionataninputpeakvoltageof2300Vand60ml/mingasflowrate.
简介:In-situwhite-beamsynchrotronradiationtopographicobservationsunderanelectricfieldhavebeenmadeonKTiOPO4familycrystals.Theinvestigationshowsastrongenhancementofdiffractedintensityofhklreflections(l≠0)andthetopographicextinctioncontrast,whenthefieldisappliedalongthepolaraxis.Dopedandundopedsampleswithgrown-indefectsarestudiedindetail.ItisbelievedthatthemovementofK^+ionsdrivenbythefieldleadstoalocalaccumulationofchargesandthelatticedistortion.Allthefield-relatedphenomenaappeartoberelatedtotheone-dimensionalionicconductance.