简介:随着气象部门事业结构调整和业务体制改革的深入以及业务现代化建设的快速发展,与80年代以前相比,县局预报业务体制、运作方式、可获取的信息量等已经并将继续发生显著变化.县局怎样进一步适应预报业务体制改革新形势?怎样发挥计算机终端在预报业务使用中的效能?从而在上级台的预报指导下提高预报业务水平,增强预报服务能力是摆在县局和业务管理部门面前的重要课题.1现状与问题几年来,新预报业务体制的试行,减少了各级台站长期以来的重复劳动,给台站自我发展创造了条件,增加了活力,预报业务质量基本是稳定的.近一、二年来,县级计算机终端的建立并投入业务使用,预报、情报信息量之大,传递速度之快,是传统的通讯手段无法比拟的,大大提高了天气预报的时效和准确
简介:针对目前不同时效的数值预报结果存在“跃变”问题,基于Poor—man集成预报方法的思想,综合考虑各个时效的数值预报结果,利用最小二乘法,构建了一个预报模型,并利用2005--2010年欧洲中心下发的数值预报资料对该模型的预报效果进行了验证。结果表明,该模型较好地克服了利用单一时次预报带来的预报结果“跃变”的不足,对提高预报水平具有一定的作用。
简介:Photocatalyticwatersplittingandcarbondioxidereductionprovideuscleanandsustainableenergyresources.Thecarbondioxidereductionisalsotheredemptionofthegreenhouseeffect.MoS3/TiO2photocatalystsbasedonTiO2nanoplateshavebeensynthesizedviaahydrothermalacidificationrouteforwaterandcarbondioxidereductionreactions.ThisfacileapproachgenerateswelldispersedMoS3withlowcrystallinityonthesurfaceofTiO2nanoplates.Theas-synthesizedMoS3/TiO2photocatalystshowedconsiderableactivityforbothwaterreductionandcarbondioxidereduction.ThethermaltreatmenteffectsofTiO2,theloadingpercentageofMoS3andthecrystallinephaseofTiO2havebeeninvestigatedtowardsthephotocatalyticperformance.TiO2nanoplatesynthesizedthroughhydrothermalreactionwiththepresenceofHFacidisanidealsemiconductormaterialfortheloadingofMoS3forphotocatalyticwaterandcarbondioxidereductionsimultaneouslyinEDTAsacrificialsolution.
简介:Two-dimensionalmaterialsaregeneratinggreatinterestduetotheiruniqueelectricalandopticalproperties.Inparticular,transitionmetaldichalcogenidessuchasmolybdenumdisulfide(MoS2)areattractivematerialsduetotheexistenceofadirectbandgapinthemonolayerlimitthatcanbeusedtoenhancenonlinearopticalphenomena,suchasRamanspectroscopy.Here,wehaveinvestigatedfour-wavemixingprocessesinbulkMoS2usingamultiplexcoherentanti-StokesRamanspectroscopysetup.Theobservedfour-wavemixingsignalhasaresonanceatapproximately680nm,correspondingtotheenergyoftheAexcitonictransitionofMoS2.Thisresonancecanbeattributedtotheincreasedthird-ordernonlinearsusceptibilityatwavelengthsneartheexcitonictransition.ThisphenomenoncouldopenthepathtousingMoS2asasubstrateforenhancingfour-wavemixingprocessessuchascoherentanti-StokesRamanspectroscopy.
简介:NativedefectsinHfSiO_4areinvestigatedbyfirstprinciplescalculations.TransitionlevelsofnativedefectscanbeaccuratelydescribedbyemployingthenonlocalHSE06hybridfunctional.Thismethodologyovercomesthebandgapproblemintraditionalfunctionals.BybandalignmentsamongtheSi,GaAsandHfSiO_4,weareabletodeterminethepositionofdefectlevelsinSiandGaAsrelativetotheHfSiOibandgap.Weevaluatethepossibilityofthesedefectsactingasfixedcharge.Nativedefectsleadtothechangeofvalenceandconductionbandoffsets.Gateleakagecurrentisevaluatedbythebandoffset.Inaddition,wealsoinvestigatediffusionsofnativedefects,anddiscusshowtheyaffecttheMOSdeviceperformance.
简介:【 摘要】 LTE语音解决方案以 VoLTE为主,语音质量是影响服务质量的最关键因素,而语音质量主要以 MOS值来评价。本文主要介绍质差环境下 VoLTE语音 MOS质量的提升方法。
简介:TheMoS2catalystswerepreparedfromvariousmolybdateprecursorsincludinginorganicandorganicmolybdatecompounds.ThesulfidationdegreeandmorphologyofactivephasesofMoS2activatedbyvariousmolybdateprecursorsinH2S/H2streamatdifferenttemperatureswerestudiedbyX-rayphotoelectronspectroscopy(XPS)andhigh-resolutiontransmissionelectronmicroscopy(HRTEM).TheorganicmolybdateprecursorsleadtoMoS2catalystswithhighersulfidationdegreeandsmalleractivephasestodemonstratehighercatalyticactivityduringhydrodesulfurizaiton(HDS)of4,6-DMDBT.