简介：提出了一种新型OCDMA多维码构造方案.该多维码是在一维EPC(扩展的素数码)时域码的基础上,对其进行PC(素数码)跳频编码,并加上了偏振信息.然后通过偏振片和FBG(布拉格光线光栅)实现这种码的编解码,详述了其特点,最后描述了使用该地址码进行信息传输的OCDMA系统结构.计算表明该新型地址码具有更大的容量,能容纳更多的用户同时通信.

简介：针对典型目标识别问题,提出了一种基于投影寻踪的高光谱目标识别算法。先对高光谱图像进行最小噪声分离变换,计算出本征维度,同时对图像去噪,然后采用信息散度作为投影指标,对投影指标值自适应分割,得到所要提取的波谱曲线,最后用光谱角匹配识别出目标及其位置。高光谱图像验证结果表明,该方法有效地去除了图像噪声,而且能够快速、可靠地提取端元并识别出目标。

简介：论述了一种典型隐形防伪二维码识读系统的光学设计方法。设计合理利用反光镜折断光路减小检测面法线方向光学长度，使得系统总体紧凑协调，同时保证了图像处理所要求的高质量成像要求，这种设计的优点对大检测面场合尤其显著。最后通过实例分析给出了清晰的设计计算过程，计算结果满足初始的设计需求。该设计方法已应用到防伪二维码识别产品中，对其他类似的证件专用识读系统（OCR阅读系统）有参考价值。

简介：目标识别与人工智能技术研究一直以来都是备受关注的前沿方向，在军用、民用领域都具有广泛的应用前景和潜在的经济价值，已成为一项极为重要和基本的技术。目标的探测与识别就是通过目标信息的“获取”、“处理”、“显示”、“传输”等途径实现目标的“探测”、“识别”和“辨识”，它是一门多学科综合的应用技术，其研究内容涉及传感器技术、信号提取、图像处理、模式识别、测试仿真等多个学科内容。

简介：在数据融合的基础上，以红外／毫米波双模传感器的智能融合结构为模型，将模糊神经网络与D-S证据理论相结合，提出了一种新的目标识别方法。该算法根据红外／毫米波传感器的性能及工作范围，构造模糊变量作为神经网络的输入，根据神经网络的不同输出判别目标的真伪，并利用D-S证据理论进行目标身份识别。仿真结果证明了该算法的可行性。

简介：针对舰船目标和海杂波轮廓结构的不同，提出了基于边缘链码高阶分形特征的舰船目标检测算法，算法利用相对链码对5类舰船目标轮廓进行编码，分别计算分形维和缝隙，得到了舰船目标的4个分形特征的范围。实验结果表明边缘链码的4个分形特征能有效区分舰船目标和海杂波。

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：Thenonlinearswitchingcharacteristicsoffusedfiberdirectionalcouplerswerestudiedexperimentally.Byusingfemtosecondlaserpulseswithpulsewidthof100fsandwavelengthofabout1550nmfromasystemofTi:sapphirelaserandopticalparametricamplifier(OPA),thenonlinearswitchingpropertiesofanullcoupleranda100%couplerweremeasured.Theexperimentalresultswerecoincidentwiththesimulationsbasedonnonlinearpropagationequationsinfiberbyusingsuper-modetheory.Nonlinearlossinfiberwasalsomeasuredtogettheinjectedpoweratthecoupler.Afterdeductingthenonlinearlossandinputefficiency,thenonlinearswitchingcriticalpeakpowersfora100%andanullfusedcouplerswerecalculatedtobe9410and9440W,respectively.ThenonlinearlossparameterPNinanexpressionofαNL=αP/PNwasobtainedtobePN=0.23W.

简介：Thepotentialenergycurves(PECs)ofBOmolecule,includingΣ+andΠsymmetrieswithdoubletspinmultiplicities,areobtainedemployingmulti-referenceconfigurationinteraction(MRCI)methodandDunning'scorrelationconsistentbasissets.Theanalyticalpotentialenergyfunctions(APEFs)arefittedusingtheMurrell-Sorbie(MS)functionandtheleastsquaremethod.BasedonthePECs,thespectroscopicconstantsofthestateshavebeendeterminedandcomparedwiththetheoreticalandexperimentalresultsavailabletoaffirmtheaccuracyandliabilityofthecalculations.Theroot-mean-square(RMS)errorsbetweenthefittedresultsandtheabinitiovaluesaretoolittleincomparisonwiththechemicalaccuracy(349.755cm-1).ItisshownthatthepresentAPEFsareaccurateandcandisplaytheinteractionbetweentheatomswell.ThepresentAPEFscanbeusedtoconstructmorecomplicatedAPEFordosomedynamicinvestigations.

简介：Usingamicrowavegenerator,chlorinedilutedbyheliumwasdissociatedtochlorineatomsthatsubse-quentlyreactedwithhydrogenazidetoproducetheexcitedstatesofNCl(a1△).Meanwhile,moleculariodinewithcarriergasofheliumreactedwithatomicchlorinetoproduceatomiciodinewhichthenwaspumpedtoexcitedstateofI(2P1/2)byanenergytransferreactionfromNCl(a1△).Inthispaper,thechangesofNCl(a1△)andNCl(bi∑)emissionintensityispresentedwhenI2/HeisintroducedintothestreamofCl/Cl2/He/HN3/NCl(a1△)/NCl(b1∑).ThedependencesofatomiciodineI(2P1/2)onflowratesofgaseswerealsoinvestigated.TheoptimumparametersforI(2P1/2)productionaregiven.

简介：FourkindsofY2O3stabilizedZrO2(YSZ)thinfilmswithdifferentY2O3contents(from0to12mol%)aredepositedonBK7glasssubstratesbyelectron-beamevaporationmethod.TheeffectsofdifferentY2O3dopantcontentsonresidualstress,structure,andopticalpropertiesofZrO2thinfilmsareinvestigated.TheresultsshowthatresidualstressinYSZthinfilmsvariesfromtensiletocompressivewiththeincreaseofY2O3molarcontent.TheadditionofY2O3isbeneficialtothecrystallizationofYSZthinfilmandtransformationfromamorphoustohightemperaturephase,andtherefractiveindexdecreaseswiththeincreaseofY2O3molarcontent.Moreover,thevariationsofresidualstressandtheshiftsofrefractiveindexcorrespondtotheevolutionofstructuresinducedbytheadditionofY2O3.

简介：Ag-MgF2cermetfilmswithdifferentAgfractionswerepreparedbyvacuumevaporation.Themicrostruc-tureofthefilmswasexaminedbyRamanscatteringtechnique.Thesurface-enhancedRamanspectrumforMgF2moleculesinthecermetfilmstronglysuggeststheexistenceofAgnanoparticlesdispersedinMgF2matrix.TheintensitiesoftheRamanspectraofAg-MgF2cermetfilmsincreasewithAgfraction.TheenhancementofRamanscatteringdisappearswhenAgcontentreacheswt.20%.TheanalyseswiththetransmissionelectronmicroscopyshowedthatAg-MgF2cermetfilmsaremainlycomposedofamor-phousMgF2matrixwithembeddedfaced-center-cubicAgnanoparticles.Itsuggeststhatthepercolationthresholdshouldbearoundwt.20%ofAgcontent.

简介：Nitridatedβ-Ga_2O_3(100)substratewasinvestigatedasthesubstrateforGaNepitaxialgrowth.Theeffectsofnitridationtemperatureandsurfaceroughnessofβ-Ga_2O_3wafersontheformationofGaNwerestudied.Itwasfoundthatthemostoptimizednitridationtemperaturewas900°C,andhexagonalGaNwithpreferredorientationwasproducedonthewell-polishedwafer.Thenitridationmechanismwasalsodiscussed.

简介：AprototypeRamanlidarwasdesignedformonitoringtroposphericCO_2profileandotherscientificin-vestigations.ThethirdharmonicofNd:YAGlaser(354.7-nmwavelength)wasusedasstimulatedlightsourcetoprovidenighttimemeasurements.FilterwithhighrejectionratioperformancewasusedtoextractCO_2RamansignalsfromRayleigh-Miescatteringsignalseffectively.Toimprovetherealtimemonitoringfunction,atwo-channelsignalcollectionsystemwasdesignedtocollectCO_2andN_2Ramanscatteringsig-nalssimultaneously.TheN_2Ramanscatteringsignalswereusedtoretrieveaerosolextinctioncoefficient.TypicalfeaturesofCO_2concentrationprofileandaerosolextinctioncoefficientinHefeiwerepresented.ThemixingratioofatmosphericCO_2inHefeicanreachabout360-400ppmv.

简介：采用HCl与NH2·H2O分步催化制各了SiO2胶体，在同一终点pH值下可得到不同的粒度,用静电自组装法制各了PDDA／SiO2有机／无机多层复合光学增透薄膜。用TEM测试了薄膜的微观结构，用721分光光度计监测了薄膜的透射率，研究了薄膜的光学性能随薄膜层数及波长的变化。

简介：选用高功率脉冲TEACO2激光器,对不同颜色不同种类的油漆进行了清洗实验,运用数码照片分析程序计算出清洁率,找出了完全清洗阈值和损伤阈值.实验结果较为清晰地给出了激光输出能量和重复频率对清洗效果的影响.对红色醇酸漆来说,完全清洗阈值为10.37J/cm^2,而损伤阈值为11.43J/cm^2;红色金属喷漆的完全清洗阈值为9.66J/cm^2,其损伤阈值达10.37J/cm^2;黄色金属喷漆的完全清洗阈值为10.71J/cm^2,损伤阈值则为11.07J/cm^2.输出能量和重复频率未达指定参数时,激光清洗清洁率则低于100%.

简介：以正硅酸乙酯为前驱体，乙醇为溶剂，盐酸为催化剂，采用溶胶-凝胶法制备了用于压敏漆基质薄膜材料的SiO2溶胶。不同的成膜助剂对SiO2溶胶的涂膜性能影响较大，其中以异丙醇作为添加剂的溶胶涂膜性能最好。吸收光谱测试结果表明SiO2溶胶不吸收激发光，同时发射光谱研究结果表明SiO2溶胶发光波长为415nm左右，不影响压敏漆探针分子的发光。

简介：Becausepulserepetitionrateaffecteddirectlythemomentumcouplingcoefficientoftransverselyexcitedatmospheric(TEA)CO2laserpropulsion,adoublepulsetrigger,controllinghighvoltageswitchoflaserexcitationcircuit,wasdesigned.Thepulseintervalrangedbetween5and100ms.Themomentumcouplingcoefficientforair-breathingmodelaserpropulsionwasstudiedexperimentally.Itwasfoundthatthemomentumcouplingcoefficientdecreasedwiththepulserepetitionrateincreasing.

简介：WhenfemtosecondlaserpulsesinterferewithchirpedfemtosecondlaserpulsesinAs2S3fiber,achirpedfibergratingisformed.Ananalyticalexpressionisgiventodescribethechirpedgrating,anditsBraggreflectivityiscalculated.BecauseofthehighphotosensitiveeffectofAs2S3material,thechirpedfibergratinghasawideBraggreflectivespectrumandhighreflectivitybychoosingproperparameters.Thisindicatesthatthechirpedfibergratingcanbeusedasastretcherinthefemtosecondchirpedpulseamplification(CPA)system.

简介：Thecombinationofdeepwetetchingandamagneto-rheologicalfinishing(MRF)processisinvestigatedtosimultaneouslyimprovelaserdamageresistanceofafused-silicasurfaceat355nm.ThesubsequentlydepositedSiO2coatingsareresearchedtoclarifytheimpactofsubstratefinishingtechnologyonthecoatings.Itisrevealedthatadeepremovalproceedingfromthesinglesideordoublesidehadasignificantimpactonthelaser-induceddamagethreshold(LIDT)ofthefusedsilica,especiallyfortherearsurface.Afterthedeepetching,theMRFprocessthatfolloweddoesnotactuallyincreasetheLIDT,butitdoesamelioratethesurfacequalitieswithoutadditionalLIDTdegradation.Thecombinationguaranteeboththeintegrityofthesurface’sfinishandthelaserdamageresistanceofthefusedsilicaandsubsequentSiO2coatings.