简介:一曲动人的《美丽的亚美利加》给我们带到了美国雄伟壮丽的落基山脉,那里的一座海拔4300米气势奇特的山峰,它就是冬天里山上雪花纷飞,峰顶白雪皑皑的“美丽之山”——派克峰。
简介:Graycrosscorrelationmatchingtechniqueisadoptedtoextractcandidatematcheswithgraycrosscorrela-tioncoefficientslessthansomecertainrangeofmaximalcorrelationcoefficientcalledmulti-peakcandidatematches.Multi-peakcandidatesareextractedcorrespondingtothreeclosestfeaturepointsatfirst.Thecorrespondingmulti-peakcandidatematchesareusedtoconstructthemodelpolygon.Correspondenceisdeterminedbasedonthelocalgeometricrelationsbetweenthethreefeaturepointsandthemulti-peakcandidates.Thedisparitytestandtheglobalconsistencycheckoutareappliedtoeliminatetheremainingambiguousmatchesthatarenotremovedbythelocalgeometricrelationaltest.Experimentalresultsshowthattheproposedalgorithmisfeasibleandaccurate.
简介:TransientthermalimpedanceofGaN-basedhigh-powerwhitelightemittingdiodes(LEDs)iscreatedusingathermaltransienttester.Anelectro-thermalsimulationshowsthatLEDjunctiontemperature(JT)risestoaverylowdegreeunderlowdutycyclepulsedcurrent.AtthesameJT,emissionpeaksareequivalentatpulsedandcontinuouscurrents.Moreover,thediferenceinpeakwavelengthwhenaLEDisdrivenbypulsedandcontinuouscurrentsinitiallydecreasesthenincreaseswithincreasingpulsewidth.Thus,selectinganappropriatepulsewidthdecreaseserrorsinJTmeasurement.
简介:ThestimulatedBrillouinscattering(SBS)thresholdaffectedbyrepetitionrateandpulsedurationinasinglefrequencynanosecondpulsedfiberamplifierisstudied.TheexperimentalresultsdemonstratethattheSBSthresholdcanbeimprovedeitherbyreducingtherepetitionrateorbynarrowingthepulseduration;however,theaveragepowermaybelimitedinsomecases.Otherwise,twoevaluationmethodsfortheSBSthresholdinthefiberamplifierarecomparedanddiscussed,aimingtoobtainamoreaccuratedescriptionfortheSBSthresholdinoursingle-frequencyamplifiersystem.