简介：“佛界-西藏壁画展”暨“巴定记忆-西藏乡村风情摄影展”在北京摄影艺术展览馆开幕，此次展览展出了西藏著名摄影艺术家高志勇八十多幅壁画摄影作品和八十多幅西藏乡村人文景观摄影作品。

简介：摘要本文提出了一种基于局部自动搜索和光谱匹配技术的训练样本纯化的BP网络分类方法。利用影像的空间信息在图像局部范围内自动搜索和选择最佳样区位置，再用光谱匹配对寻找到的最佳样区在光谱空间上进一步纯化。从空间和光谱两个角度对样区进行了纯化，使得训练样本更适合遥感图像分类的要求，最后利用BP网络对遥感图像进行分类。实验结果证明，原始遥感图像经过样区纯化算法处理后，目视判读效果和数值分析都表明提高了分类精度。

简介：Inthisworkpulsegenerationinboththe1.5and2μmspectralrangesusingagrapheneoxide(GO)-paper-basedsaturableabsorberinEr-andTm-dopedfiberlasersispresented.ThearticledescribesthefabricationmethodofGOpaperanditscharacterization.Theperformanceofbothlasersisdiscussedindetail.Stable,mode-lockedoperationprovides613fsand1.36pssolitonpulsescenteredat1565.9and1961.6nminEr-andTm-dopedfiberlasers,respectively.Furthermore,scalingofspectralwidth,andhencethepulseduration,byincreasingthenumberofGOpaperlayersintheEr-dopedlaserisdescribed.TheversatilityandsimplicityofGOpaperfabricationcombinedwiththepossibilityofscalingtheopticalspectrumfullwidthathalf-maximumareessentialfeaturesthatmakeitagoodcandidateforultrafastlow-powermode-lockedlasersoperatingindifferentspectralregions.

简介：Background:Accelerometershavebeensuggestedtoprovideadditionalinformationduringthe6-minwalktestwhichmaybeusefulinevaluatingchangesinfunctionalexercisecapacity.TheaimofthestudywastoidentifywhethertheadditionalinformationmeasuredbytheMyWellnessKey~(TM)(MWK)accelerometerduringatreadmill6-minwalktest(t-6MWT)wasrelatedtocurrentlyusedoutcomemeasures.Methods:Fifteenparticipants(9males,6females)performedaself-pacedt-6MWT.RespiratorygasanalysisandwalkingdistanceweremeasuredwhilstwearingtheMWK.Results:Asignificantcorrelationwasestablishedbetweenactivitycountsand6-minwalkdistance(6MWD)(r=-0.847,p<0.001)yetnot6-minwalkwork(6MWW)(r=-0.337,p=0.220).EnergyexpenditureestimatedbytheMWKwasstronglycorrelatedto6MWW(r=0.938,p<0.001)butnot6MWD(r=0.477,p=0.072).TheMWKsignificantlyunderestimatedenergyexpenditure(36.73,CI=33.9-39.7kcal)comparedtogasanalysis(54.35,CI=46.2-61.4kcal)demonstratingpooragreementbetweenthetwoanalyses(Bias=-17.61kcal,Limitsofagreement=-37.4,t2.2kcal).Measurementoftimespentundertakinglight,moderate,andvigorousphysicalactivitywasnotsignificantlydifferent(p>0.05)betweentheMWKandgasanalysis.Conclusion:EstimatedenergyexpenditureprovidedbytheMWKwasstronglycorrelatedto6MWW;however,MWKunderestimatedenergyexpenditureasmeasuredbygasanalysis.TheMWKmayprovideoutcomedatathatsupplementthosecurrentlyprovidedbythe6MWDforfunctionalcapacityassessmentduringthet-6MWT.

简介：LanthanidedopedNaYF4microcrystalsweresynthesizedviaafacilehydrothermalmethod.MulticolorupconversionluminescencewasobservedinNaYF4microcrystalsdopedwithYb3+/Er3+,Yb3+/Tm3+,andYb3+/Er3+/Tm3+undertheexcitationof980nminfraredlight.Importantly,theexcitationpowerdensitydependenceofupconversionemissionintensityindicatedclearlytheenergytransferfromTm3+toEr3+ionsundertheexcitationoflowpowerdensity(5×102–9×102W/cm2).Meanwhile,theinverseenergytransferfromEr3+toTm3+ionsundertheexcitationofrelativelyhigherpowerdensity(4.1×104–4.9×104W/cm2)wasalsorevealed.ThiswasadirectevidenceforreversibleenergytransferbetweenEr3+andTm3+ions.Undertheexcitationofhighpowerdensity(4.1×104–4.9×104W/cm2),darksensitizerswerealsomotivatedsothatthebottleneckeffectofhighconcentrationYb3+iondopingwasbroken.ThiswasthemainreasonforrealizinghighupconversionefficiencyofthesampleswithheavydopingofYb3+ion.

简介：Amolybdenumdisulfide（MoS2）saturableabsorberwasfabricatedbythermallydecomposingtheammoniumthiomolybdate.ByusingtheMoS2absorber,acompactdiode-pumpedpassivelyQ-switchedTm:GdVO4laserhasbeendemonstrated.AstableQ-switchedlaserwithrepetitionratesfrom25.58to48.09kHzwasachieved.Maximumaverageoutputpowerwas100mWwiththeshortestpulsedurationof0.8μs.Maximumpulseenergyis2.08μJatcenterof1902nm.

简介：2014年11月27日，索尼（中国）有限公司正式发布了α系列便携全画幅微单^TM数码相机新品α711（型号名：ILCE-7M2）。α711采用约2430万有效像素的全画幅ExmorCMOS影像传感器，并内置BIONZX影像处理器，

简介：

简介：WithMoS2assaturableabsorber,passiveQ-switchingandQ-switchedmode-lockingoperationsofaTm-dopedcalciumlithiumniobiumgalliumgarnet（Tm:CLNGG）laserwereexperimentallydemonstrated.TheQ-switchedlaseremittedamaximumaverageoutputpowerof62mWandhighestpulseenergyof0.72μJ.Q-switchedmodelockingwasalsoobtainedintheexperiment.TheresearchresultswillopenupapplicationsofMoS2atthemid-infraredwavelength.