简介:由于Newman有理算子对|x|逼近效果较好,所以考虑利用Newman-α型有理算子对|x|~α进行逼近.构造Newman-α型有理算子,讨论Newman-α算子在Chebyshev结点组下逼近|x|~α的收敛速度,最后得到精确的逼近阶为O(1/(n~αlogn)).该结果包含了α=1时的情形.
简介:Theeffectofλ/2SiO2overcoatonthelaserdamagecharacteristicsofHfO2/SiO2high-reflector(HR)coatingsisinvestigatedwith1-on-1andN-on-1laserdamagetestmethods.Thelaserdamagesurfaceof1-on-1isanalyzedbyastepanalyzer.ThesurfacemorphologiesshowthatlaserdamagemakesthecoatingdamagedareaprotrudentandroughforHRcoatingwithoutλ/2silicaovercoat,butconcaveandsmoothforHRcoatingwithλ/2silicaovercoat.Theresultof10-on-1multi-pulseirradiationonthesamepointofthecoatingshowsthatthereisanenergydensitystageonthedamagecurve.Ifthelaserenergydensityiswithintherangeofthestage,HfO2/SiO2HRcoatingswithλ/2silicaovercoatwillnotbedamagedmorethan2timesformulti-shots,andthesurfacedamagesareveryslightsothatthereisnoimpactonthecoatingperformance.Anotherinterestingresultisthattheenergydensitystageextendsfromthedamagethresholdtothepointofabout3timesofthreshold,whichissimilartotheeffectofthelaserconditiononcoating.
简介:FF系列是环球影业的“摇钱树”第七部是所有系列中唯一一部票房超过10亿美金的,这一纪录打破了《阿凡达》此前的纪录,并成为史上最快超过10亿美金的电影.FF系列越来越多的收入来自于美国以外的市场,全部电影的票房加起来将近40亿美金,其中有75%来自于海外市场.它也是环球影业最挣钱的一个系列电影.第七部成功之后,环球影业立即趁热打铁地决定,再拍三部,每两年一部.范·迪塞尔(VinDiesel)和道恩·强森(DwayneJohnson)两大主演是票房的保证,而他们的日程也越来越紧张,能够留住他们非常的关键,如果环球影业可以做到这点,相信接下来的FF系列还能再创佳绩.FF系列的灵感来自真人真事环球影业的前总裁斯科特·斯塔博(ScottStuber)看到Vibe杂志上关于纽约街头飙车的报道,并把它拿给制作人尼尔·H·莫瑞兹(NealH.Moritz期导演罗伯·科恩(RobCohen)看.本来罗伯·科恩兴趣不大,觉得不会有市场,但在亲身参加了一场洛杉矶的街头赛车后,改变了主意.当年这篇文章的作者肯·李(KennethLi)和街头赛车手拉斐尔·埃斯特维兹(RafaelEstevez)是朋友.拉斐尔·埃斯特维兹在非法赛车界是个传奇,赢了很多场高风险的赛事,并经常把自己的本田Civic飙到320公里/小时的速度以摆脱警察的追击.他现在在纽约的皇后区经营一个车库.
简介:SiO_2thinfilmscontainingSi_(1-x)Ge_xquantumdots(QDs)arepreparedbyionimplantationandannealingtreatment.Thephotoluminescence(PL)andmicrostructuralpropertiesofthinfilmsareinvestigated.ThesamplesexhibitstrongPLinthewavelengthrangeof400—470nmandrelativelyweakPLpeaksat730and780nmatroomtemperature.Blueshiftisfoundforthe400-nmPLpeak,andtheintensityincreasesinitiallyandthendecreaseswiththeincreaseofGe-dopingdose.Weproposethatthe400—470nmPLbandoriginatesfrommultipleluminescencecenters,andthe730-and780-nmPLpeaksareascribedtotheSi=OandGeOluminescencecenters.
简介:日前,《中华人民共和国国家标准批准发布公告2009年第2号》正式发布。其中,13项产品几何技术规范(GPS)系列国家标准被修订,内容如下:
简介:Thenonlinearswitchingcharacteristicsoffusedfiberdirectionalcouplerswerestudiedexperimentally.Byusingfemtosecondlaserpulseswithpulsewidthof100fsandwavelengthofabout1550nmfromasystemofTi:sapphirelaserandopticalparametricamplifier(OPA),thenonlinearswitchingpropertiesofanullcoupleranda100%couplerweremeasured.Theexperimentalresultswerecoincidentwiththesimulationsbasedonnonlinearpropagationequationsinfiberbyusingsuper-modetheory.Nonlinearlossinfiberwasalsomeasuredtogettheinjectedpoweratthecoupler.Afterdeductingthenonlinearlossandinputefficiency,thenonlinearswitchingcriticalpeakpowersfora100%andanullfusedcouplerswerecalculatedtobe9410and9440W,respectively.ThenonlinearlossparameterPNinanexpressionofαNL=αP/PNwasobtainedtobePN=0.23W.