简介：铱(Iridium)再次成功发射七枚卫星,令整个铱计划已发射的卫星总数增至63枚．占计划发射66枚的90％,这七枚卫星可担任覆盖全球之话务、数据、传真及传呼等个人通讯眼务．这次是铱公司第十三次成功发射卫星．未来星期将再有2次发射计划.

简介：Carbonsupportedgold-iridiumcomposite(AuIr/C)wassynthesizedbyafacileone-stepprocessandwasinvestigatedasthebifunctionalcatalystforoxygenreductionreaction(ORR)andoxygenevolutionreaction(OER).ThephysicalpropertiesoftheAuIr/Ccompositewerecharacterizedbytransmissionelectronmicroscopy(TEM),X-raydiffraction(XRD)andX-rayphotoelectronspectroscopy(XPS).AlthoughtheAuandIrintheAuIr/Cdidnotformalloy,itisclearthattheintroductionofIrdecreasestheaverageAuparticlesizeto4.2nmcomparedtothatintheAu/C(10.1nm).BysystematicalanalysisonchemicalstateofmetalsurfaceviaXPSandtheelectrochemicalresults,itwasfoundthattheAusurfacefortheAu/Ccanbeactivatedbypotentialcyclingfrom0.12Vto1.72V,resultingintheincreasedsurfaceroughnessofAu,thusimprovingtheORRactivity.Bythesamepotentialcycling,theIrsurfaceoftheIr/Cwasirreversiblyoxidized,leadingtodegradedORRactivitybutuninfluencedOERactivity.FortheAuIr/C,IrprotectsAuagainstbeingoxidizedduetothelowerelectronegativityofIr.CombiningtheadvantagesofAuandIrincatalyzingORRandOER,theAuIr/CcatalystdisplaysanenhancedcatalyticactivitytotheORRandacomparableOERactivity.Inthe50-cycleacceleratedagingtestfortheORRandOER,theAuIr/Cdisplayedasatisfiedstability,suggestingthattheAuIr/Ccatalystisapotentialbifunctionalcatalystfortheoxygenelectrode.

简介：本文介绍了一种车载线天线，该天线采用遗传算法业设计，它既可以用于GPS系统，也可以用于IRIDIUM系统。这种天线具有右旋圆极化和半球覆盖性能，其工作频段为1225－1625MHz。这种天线采用数字电磁代码（NEC）来模拟，然后加以制作和测试。它由5个串联的铜管线段（segment)组成，其形状非常奇特，而且价格非常便宜，其体积近似为10cm×10cm×15cm。计算并测量了输入电压驻波比（VSWR）和圆极化辐射方向图。VSWR在1225MHz、1575MHz和1625MHz设计频率上小于2.2。在170°的天线扇区内天线增益的变化小于12dB。一般来说，增益会在水平线附近减小。因此，在天线扇区为150°和160°时天线增益的变化更小。这种新的天线设计采用了遗传算法和电磁码，它有几种非常特殊的天线结构，这些天线结构都已被证明其工作性能比常规设计的工作性能好。

简介：ThesynthesisandphosphorescencepropertiesoftwonovelIr（Ⅲ）complexesbearingtert-butylsubstituents,bis(4-tert-butyl-2-phenylbenzothiozolato-N,C2′)iridium（Ⅲ）（acetylacetonate）[（tbt）2Ir（acac）]andbis(4-tert-butyl-1-phenyl-1H-benzimidazolato-N,C2′)iridium（Ⅲ）（acetylacetonate）[（tpbi）2Ir（acac）],arereported,theirmolecularstructuresareconfirmedby1HNMR,ESI-MSandelementaryanalysis.Photoluminescence（PL）studiesrevealedthattheycanemitstronggreenandorangephosphorescenceinhighquantumyields.Comparedtotheirprototypeslackingoftert-butylsubstituents,thetwonoveliridium（Ⅲ）complexesbothhaveshorterlifetimesandimprovedornearlysimilarPLquantumefficiencies,implyingthattheexcitonquenchingisinhibitedeffectivelywhenmolecularsterichindranceincreases.Thetwochelateshavegreatpotentialtobeusedaselectrophosphorescentmaterials.

简介：Iridiumnanoparticles(IrNPs)andsubmicroparticles(IrSMPs)withdifferentshapesweresynthesizedandassembledonindiumthinoxide(ITO)andSisubstratesusingtwodifferentmethods:directsurfacegrowthanddrop-dryingassembly.TheobtainedIrNPsandIrSMPswerecharacterizedusingscanningelectronmicroscopy(SEM)andenergydispersivespectroscopy(EDS).TheIrSMPs(orIrNPs)withdisc-likeshapeandirregularshapeswereobtainedonITOsubstratebydirectsurfacegrowthmethodusingpolyvinylpy...

简介：Thesynthesisandspectrophotometricpropertiesof2-(6-methyl-2-benzothiazolylazo)-5-diethylaminophenol(MBTAE),andtheuseofitasaprecolumnderivatizingreagenttoseparateCo(Ⅱ),Ni(Ⅱ),Rh(Ⅲ)andIr(Ⅳ)complexesbyHPLCarediscussed.Whenthemobilephaseconsistsofmethanol/water(90/10Ⅴ/Ⅴ),acetatebufferwithpH4.0and5×10-5mol/LEDTAsolution,thefourcomplexesCanbeseparatedwithin9minonODScolumn.Thedetectionlimits(20μLsamplesize)are0.059ppb,0.062ppb,0.053ppband0.049ppbforCo(Ⅱ),Rh(Ⅲ),Ni(Ⅱ)andlr(Ⅳ)respectivelyatasignal-to-noiseratioof3.