简介:Consideringanopticalbistablesystemwithcross-correlatedadditivewhitenoiseandmultiplicativecolorednoise,westudytheeffectsofcorrelationbetweenthenoisesonthecorrelationfunctionC(s)usingtheunifiedcolorednoiseapproximationandtheStratonovichdecouplingansatzformalism.Theeffectsoftheself-correlationtimeTofthemultiplicativecolorednoiseandthecorrelationintensityλbetweenthetwonoisesarestudiedwithnumericalcalculation.ItisfoundthatC(s)increaseswiththeincreaseoftheself-correlationtimeT,butdecreaseswiththeincreaseofthecorrelationintensityλ.AtlargevalueofT,thereisalmostnochangeforC(s)whenTchanges.
简介:Wefabricatewhitephosphorescentorganiclight-emittingdiodes(PHOLEDs)withthreedopantsanddoubleemissivelayer(EML)toachievecolorstability.ThewhitePHOLEDsuseFIrpicdopantforblueEML(BEML),andIr(ppy)3:Ir(piq)3dopantsforgreen:redEML(GR-EML)withN,N′-dicarbazolyl-3,5-benzene(mCP)ashostmaterial.ThicknessesofB-EMLandGR-EMLareadjustedtoformanarrowrecombinationzoneattwoEML’sinterfaceandchargetrappinghappensinEMLaccordingtowidehighestoccupiedmolecularorbitaland/orlowestunoccupiedmolecularorbitalenergybandgapofmCPandsmallerenergybandgapofdopants.ThetotalthicknessofbothEMLsisfixedat30nminthedevicestructureofITO(150nm)/MoO3(2nm)/N,N′-diphenyl-N,N′-bis(l-naphthyl-phenyl)-(l,l′-biphenyl)-4,4′-diamine(70nm)/mCP:Firpic-8.0%(12nm)/mCP:Ir(ppy)3-3.0%:Ir(piq)3-1.5%(18nm)/2′,2′,2′′-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole)(30nm)/8-hydroxyquinolinolato-lithium(2nm)/Al(120nm).WhitePHOLEDshows18.25cd/Aofluminousefficiencyandwhitecolorcoordinatesof(0.358and0.378)at5000cd/m2andcolorstabilitywithslightCIEXYchangeof(0.028and0.002)asincreasingluminancefrom1000to5000cd/m2.
简介:TransientthermalimpedanceofGaN-basedhigh-powerwhitelightemittingdiodes(LEDs)iscreatedusingathermaltransienttester.Anelectro-thermalsimulationshowsthatLEDjunctiontemperature(JT)risestoaverylowdegreeunderlowdutycyclepulsedcurrent.AtthesameJT,emissionpeaksareequivalentatpulsedandcontinuouscurrents.Moreover,thediferenceinpeakwavelengthwhenaLEDisdrivenbypulsedandcontinuouscurrentsinitiallydecreasesthenincreaseswithincreasingpulsewidth.Thus,selectinganappropriatepulsewidthdecreaseserrorsinJTmeasurement.
简介:模型汽车的诞生模型汽车的出品是在实际汽车之后,自从1914年美国Tool-Dietoy公司制造了世界上第一个汽车模型-福特T型之后,就有人开始收藏汽车模型了。当时汽车模型仅是作为一种新奇的推销手段。
简介:在视频编码中,DCT系数分布模型是率失真理论模型的基础,视频量化一般可分别为硬判决量化(HDQ)以及软判决量化(SDQ),SDQ算法能实现最优编码性能,但其中维特比算法会导致严重的系数间串行处理依赖.比较而言,基于死区(deadzone)的HDQ算法率失真性能略有损失,但是不考虑系数间的相关性.提出了一种基于分段逼近TCM模型(TransparentCompositeModel)的自适应硬判决量化算法,采用更精确的DCT分布估计模型,估算不同频率分量DCT系数的分布参数.根据模型参数及DCT系数分布参数,优化构造自适应的死区偏移量模型.实验表明,相对于固定偏移量HDQ算法,其编码性能非常接近于SDQ算法.