简介:运用Zemax光学设计软件构建Liou-Brennan眼模型,设计了增大焦深的非球面、折射型多焦点和衍射型多焦点人工晶体,并用点列图和视锐度分析了所设计的人工晶体的光学质量。对于非球面人工晶体,在3mm瞳孔下,当人眼无球差时,最佳视锐度相当高,但焦深仅为1.4m^-1;当人眼球差为0.4λ时,最佳视锐度可达0.9,焦深达2.2m,同时在整个焦深范围内视觉质量均优越。对于衍射型和折射型多焦点人工晶体,在明视条件下,虽然视远和视近时视觉质量良好,但是中间距离的视锐度〈0.5。衍射型多焦点人工晶体只有81%的光能用于成像,远近焦点能量均分,且与瞳孔大小无关;折射型多焦点人工晶体的远近焦点能量与瞳孔大小相关。设计的人工晶体均能增大人眼的焦深,但各有优缺点,临床上应该酌情选用。
简介:High-strengthsteelshavebeenwidelyappliedtoautomotivechassisparts.Inordertoformcomplexshapes,highholeexpansionratesandhighformabilityarerequired.Dualphase(DP)steelhasagoodformability,butapoorholeexpansionrate.Inthiscircumstance,anotherkindofsteelwhichhasamicrostructureofferrite-bainite,ratherthanferrite-martensite,hasbeenfoundtobeanalternativesolution.ItiscalledFBsteel.ThissteelwithSi,CandMnadditionsareappliedinthisstudy.Atwo-stepcooling...
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:MoleculardynamicssimulationsareperformedtoinvestigateCF3continuouslybom-bardingtheamorphoussiliconsurfacewithenergiesof10eV,50eV,100eVand150eVatnormalincidenceandroomtemperature.TheimprovedTersoff-Brennerpotentialswereused.Thesimu-lationresultsshowthatthesteady-stateetchingratesareabout0.019,0.085and0.1701for50eV,100eVand150eV,respectively.Withincreasingincidentenergy,atransitionfromC-richsurfacetoF-richsurfaceisobserved.IntheregionmodifiedbyCF3,SiFandCFspeciesaredominant.
简介:DenseSi3N4BNcompositeceramicswerefabricatedbysparkplasmasinteringat1500,1600and1650℃under50MPafor5minusingSi3N4andBNpowdersasstartingmaterialsand2mass%Al2O3and6mass%Y2O3assinteringadditives.ThevolumefractionofBNinSi3N4BNcompositepowderswaschosenas10%,20%,and30%,respectively.TheresultsofXRDandSEMshowthatα-Si3N4completelyturnsintoβ-Si3N4whenthecompositeceramicsaresinteredat1650℃;theadditionofBNhindersthegrowthofSi3N4grains,refiningthestructure;VickershardnessandfracturetoughnessofthecompositeceramicsdecreasewiththeincreaseofBNcontent.
简介:摘要白内障囊外摘出合并人工晶体植入术有许多并发症,本文将其分为术中和术后并发症二大类,对他们的预防和处理方法进行综述,以期探讨共同提高该手术的质量。
简介:摘要目的探讨小切口白内障摘除人工晶体植入临床效果。方法对176例(188眼)白内障行小切口白内障摘除人工晶体植入术,并对其临床效果进行分析。结果术后一周视力检查视力0.6以上者87眼占46.27%;术后一月视力检查视力0.6以上者168眼占89.36%。结论小切口白内障摘除手术时间短,并发症少,术后视力恢复较好。
简介:摘要目的探讨应用预装式推注器进行人工晶体(intraocularlens,IOL)植入手术的临床效果。方法超声乳化白内障吸净后,试验组76例采用预装式推注器植入ks-3(canon-staar公司),对照组67例采用传统推注器植入SN60ATIOL(ALCON公司)分别在术前,术后第1天,术后第7天,第1,第3,第6,第12个月时进行详细眼科检查,记录术中,术后并发症,结果所有患者均成功施行手术,术后各阶段视力均比术前提高(P均0.05),术中IOL破损,改变植入方法IOL翻转,IOL光学面夹痕,IOL光学面折痕,IOL襻弹出囊袋口发生率试验组分别为1.3%,2.2%,0%,0%,0%,对照组分别为0%,0%,1.5%,15.2%,9.5%,2.7%,未见其他术后并发症。结论应用预装式推注器和传统式推注器进行人工晶体植入手术均有良好的临床效果,但相比之下,预装式IOL更具备操作简单,方便清洁等优势,是一种较好的IOL植入方法。