简介:Wereportonanoveldibenzothiophene-basedtwo-photonfluorescentprobeforselectivenuclearbioimaging,whichcontainsbilaterallysymmetricalpyridineringsconnectedbyacentralconjugated-bridgedibenzothiophene.Thisprobepossessesalargetwo-photonabsorptioncross-sectionof471GM,yieldsa25-foldenhancementofthefluorescencetitration,andastrongerphotostabilityfornucleilabelingthanexistingprobes.Thereal-timeobservationperiodisaminimumof1800sunderafemtosecondlaserexcitation,whichissignificantlylongerthanthatof40,6-diamidino-2-phenylindole.Theaboveresultsconfirmthatthisnovelmoleculeisasuitabletwo-photonfluorescentprobeforapplicationtonuclearbioimagingincells.
简介:Wereportanopticallyaddressedliquidcrystallightvalve,ahome-madedevicethathassolvedtheproblemoflowtransmittancecausedbyopaqueelectrodesinpresenttransmissivespatiallightmodulators.Theoperatingcharacteristicofthelightvalveisanalyzed.Theoptimumdrivingvoltageofthisdeviceis27Vat300Hz,asdeducedfromtheequivalentelectricmodel.Itstransmittancereaches80%anditscontrastisapproximately40:1.Itsdynamicperformance,especiallyitsabilitytoobscurelaserlightatprogrammedlocations,isdemonstrated.Theresultsareingoodagreementwiththedesiredshape,whichindicatesthatourlightvalveperformsverywell.
简介:Thereisatradeoffbetweenthequantumefficiencyandthespectralresponselinewidthinresonant-cavityenhanced(RCE)photodetectors.Recentlyanewtypeofphotodetectorstructurehasbeenproposed,whichutilizesaninclinedmirrorinathree-mirrorcavity.Itdecouplesthequantumefficiencyandthespectralresponselinewidthandhashighresponsespeed,highquantumefficiency,andnarrowlinewidthsimultaneously.Theanalysisresultindicatesthatthelinewidthof0.8nmandquantumefficiencyhigherthan70%canbeachievedonthisdevice.Fora30×30μm2device,themaximumbandwidthapproaches23GHz.
简介:如果拥堵费阻力过大,采用上海等城市采用的牌照拍卖制度也能有效避免车辆购置权分配与实际需求不匹配的浪费问题。6月15日,北京市交通委公布了新的对外地牌照汽车进行进一步限行的通告。原本外地牌照车辆除了不允许上二环路和长安街主路以外,只是工作日早晚高峰不允许进入五环内部行驶,其他时间只要在手机上办理进京证,就可以在绝大部分路段行驶。推行新政后,不但限行区域从
简介:针对在四通道液压振动台及试车场路试过程中,某样车排气管支架出现的焊接螺母疲劳开裂问题,在考虑焊接螺母焊点和螺栓预紧力的前提下,建立开裂支架的局部非线性有限元模型,根据Miner线性疲劳累计损伤理论和材料S-N曲线,对正弦信号激励下的排气管支架进行疲劳分析。在此基础上,提出优化方案,进行仿真疲劳寿命预测,并对简化后的局部排气管支架模型进行疲劳验证,优化前后的仿真模型寿命曲线趋势与试验结果基本吻合,危险区域分布与试验一致。针对焊接螺母或者螺栓连接的支架疲劳开裂问题,在考虑螺栓预紧力的基础上,建立局部模型疲劳分析并结合试验验证,提出优化方案解决问题。试验结果表明,该流程方法对解决实际问题具有一定的借鉴意义。
简介:随着汽车工业的发展,汽车行、他企业的投资力度不断加大,汽车工业固定资产净值平均余额逐年增加。2000年汽车工业固定资产净值平均余额为l723.9亿元,占制造业的5.1%,同比增长10.8%,比1990年增加8.6倍,平均年增长率25.4%。其中.汽车行业七大企业集团固定资产净值平均余额占全行业总额的39.9%。作为国民经济支柱产业,汽车工业仍需大幅增加固定资产的投资。