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简介：Withthebirthofgraphenewithfasnicatingproperties,noveltwo-dimensionalnanomaterialshaveobtainedconsiderabledevelopmentsinthelastdecade.Amongthem,BNnanosheetshavebeenintensivelyinvestigatedbecauseoftheirlargeelasticmodulus,highmelting-point,superbthermalconductivityandlargedirectbandgap,whichcanbeusedinultraviolet-lightemitter,

简介：Photoniccrystalfibers(PCFs)withasteppedraised-coreprofileandonelayerequallyspacedholesinthecladdingareanalyzed.Usingeffectiveindexmethodandconsideringaraisedsteprefractiveindexdifferencebetweentheindexofthecoreandtheeffectiveindexofthecladding,weimprovethecharacteristicparameterssuchasnumericalapertureandV-parameter,andreduceitsbendinglosstoaboutonetenthofaconventionalPCF.ImplementingsuchastructureinPCFsmaybeonestepforwardtoachievelowlossPCFsforcommunicationapplications.

简介：Weinvestigatetheinteractionbetweenapositivemassandanegativeeffectivemassthroughathreemasschainconnectedwithelasticsprings,apairofmassesisdesignedtohaveaneffectivenegativemass,anditinteractswiththethirdpositiveoneasifanequivalenttwo-masschain.Thedynamicsoftheequivalenttwo-masschainshowsthatthetwobodiesmaybeself-acceleratedinsamedirectionwhentheeffectivemassbecomesnegative,theexperimentisalsoconductedtodemonstratethistypeofmotion.Wefurthershowthattheenergyprinciple(Hamilton’sprinciple)isapplicableiftheenergyofthenegativemassunitisproperlycharacterized.Theresultmayberelevanttocompositewithcellsofeffectivenegativemass,theirinteractionwithmatrixmayleadtomorericherunexpectedmacroscopicresponses.

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简介：Theeffectivethermalconductivityofmatrix-inclusion-microcrackthree-phaseheterogeneousmaterialsisinvestigatedwithaself-consistentmicromechanicalmethod（SCM）andarandommicrostructurefiniteelementmethod（RMFEM）,IntheSCM,microcracksareassumedtoberandomlydistributedandpen-ny-shapedandinclusionstobespherical,thecrackeffectisaccountedforbyintroducingacrackdensitypa-rameter,theeffectivethermalconductivityisderivedwhichrelatesthemacroscopicbehaviortothecrackdensityparameter.IntheRMFEM,thehighlyirregularmicrostructureoftheheterogeneousmediaisaccu-ratelydescribed,theinteractionamongthematrix-inclusion-microcracksisexactlytreated,theinclusionshapeeffectandcracksizeeffectareconsidered.ANi/ZrO2particulatecompositematerialcontainingran-domlydistributed,penny-shapedcracksisexaminedasanexample.Themainresultsobtainedare:（1）theeffectivethermalconductivityissensitivetothecrackdensityandexhibitsessentiallyalinearrelationshipwiththedensityparameter;（2）theinclusionshapehasasignificanteffectontheeffectivethermalconductiv-ityandapolygon-shapedinclusionismoreeffectiveinincreasingordecreasingtheeffectivethermalconduc-tivitythanasphere-shapedone;and（3）theSCMandRMFEMarecomparedandthetwomethodsgivethesameeffectivepropertyinthecaseinwhichthematrixthermalconductivityλ,isgreaterthantheinclusiononeλ2.Intheinversecaseofλ1<λ2,thetwomethodsagreeastheinclusionvolumefractionandcrackdensityarelowanddifferastheyarehigh.Areasonableexplanationfortheagreementanddeviationbetweenthetwomethodsinthecaseofλ1<λ2ismade.

简介：Takingα-FeandNd2Fe14Bgrainsasexample,thegrainsizedependenceoftheexchange-couplinginteractionandeffectiveanisotropyandalsotheirvariationsdependingontheratioofmagneticallysoftandhardgrainsizes,Ds∶Dh,wereinvestigated.WhengrainsizeD>Lex,thegrain'sanisotropyisthestatisticvalueofthecoupledanduncoupledpart.TheanisotropyconstantofuncoupledpartisthecommonvalueK1andthatofcoupledpartvarieswiththedistancetothegrainsurface.Theeffectiveanisotropyconstantbetweenmagneticallysoftandhardgrains,Keff,canbeexpressedasthesumoftheproductsofvolumefractionsforsoftandhardgrains,respectively,andthecorrespondingmeananisotropyconstants.Thecalculationresultsindicatethattheexchange-couplinginteractionisenhancedwiththereductionofgrainsize,andtheeffectiveanisotropydecreaseswithreducinggrainsizeandincreasingratioofDs∶Dh.Inordertogethigheffectiveanisotropyconstant,Keff,incompositemagneticallysoft-hardgrains,thehardgrainsizeshouldbelargerthan30nmandthesoftgrainsizeshouldbeabout10nm.

简介：Magdalena河有最大的长度(1612km)和排水区域(在哥伦比亚的任何河系统的257400km2)，和它的分水岭占据24%哥伦比亚的领土。河在加勒比海海(BocasdeCenizas)在3685m和流动的举起在Andes山脉的山脉发源到它的嘴。为这研究，每日的流动分泌物(Q)的信息，推迟的沉积运输(Qs)和平均数推迟了沉积集中(C从为Magdalena河的1990-2010的s)基于在计量车站(到嘴的最靠近的车站)的Calamar的大小，被水文学，气象学和哥伦比亚(用西班牙语的IDEAM)的环境研究的研究所提供。吝啬的年度推迟的沉积负担是169?踋???跱???????????迱??????x

简介：Basedonthesurveyresearchofpovertycontrollingmodelof'ThreeDrives,FourJoints'inZhen’anCounty,itsformingmotives,implementingmechanism,andconstraintfactorshavebeenexploredtotestifyitsenlightenmentandapplicability,establishingapromotable,applicable,andeffectivepovertyalleviationmodel.'ThreeDrives,FourJoints'modelislinkedtothepoorwholacksabilityofself-development.Relyingonthedrivesfromkeyleadingcompanies,thecapableandtherich,acommunitywithsharedinterestsbythepoorandthesubjectsofthe'threedrives'couldbeformedthrough'JointProduction,JointResources,JointCommunityofStock,andJointOperation'.Thelinkedpovertyalleviationdevelopmentmodelof'theinfluentialandtherichbringalongthepoor'and'Arichhouseholdwouldhelptheothers'comeintobeing.Itisfoundoutthatthemodelof'ThreeDrives,FourJoints'isinessenceapovertyalleviationmethodfocusingontheincreaseoftheincomeanddiversifiedwaysofincreasingtheearnings.Problemsofpovertyalleviationcarrierandjointmechanismhavebeensolvedinthepovertyalleviationprocess.Themodelisinnovativeinactivatingtheresourceelements,helpingtomovethepooroutofpoverty.Areferential,copyable,andapplicablemodelisofferedtoadvancethepovertyalleviationinmountainousareasinChina.

简介：TheChemicalFiberPlantofUrumqiPetrochemicalCompanyhasimplementedtheprojectforrecoveringthePTAmotherliquor.Thisprojectaimstorecoverthefeedstockanddesalterwaterandtoreducewastewaterdischarge.ThePTAmotherliquorfromtheoxidationunitafterbeingcooleddownin

简介：针灸的主要作用是促进气血的运行,有理由相信针刺所有的穴位都有这样的功能.本文认为针灸的治疗效应在于针刺部分最为有效的穴位就可以成功治疗任何疾病.理论依据就是气,气分阴阳,分属五行.道生一,一生气,气生阴阳,阴阳生四季和五行,五行创造了人和万物.医生可以根据阴阳五行辨证,也可以根据气辨证.由于气比阴阳五行的层次高,因此在气的水平上选择穴位将优于阴阳辨证.作者把根据其进行辨证成为'气针刺'.'气针刺'在4个层面上有不同的取穴策略:时间针刺,基本穴位,远道取穴和局部取穴或阿是穴.

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简介：A100-Gb/shigh-speedopticaltransmitterisproposedandexperimentallydemonstrated.Basedonfrequency-quadruplingtechnique,twosub-channelswithafixed50-GHzspacingareobtainedfromonelasersource.Usingreturn-to-zerodifferentialquadraturephase-shiftkeying(RZ-DQPSK)modulationformatandpolarizationmultiplexing(PolMux),onlylow-speedelectronicdevicesof12.5GHzareneededforthe100-Gb/stransmitter.Thiseliminatestheneedofultrahigh-speedoptoelectronicdevicesandthusgreatlyreducesthecost.Theexperimentalresultsshowthatthistransmittercanachievegoodperfor-manceindispersiontoleranceofa25-kmsinglemodefiber(SMF).

简介：复杂系统除了受到不确定性的影响以外,还常常演化为多重时间尺度和(或)多重空间尺度。因此,相应的随机偏微分方程模型包含了时间空间上的多尺度。段金桥与王伟的新书《EffectiveDynamicsofStochasticPartialDifferentialEquations(随机偏微分方程的有效动力学)》重点研究具有快慢时间尺度及大小空间尺度的随机偏微分方程,将平均、慢流形、均匀化等基本技巧发展到随机偏微分方程中,从中萃取出有效动力学。这本书之所以提出有效动力学的原因有二:一方面,有效动力学正

简介：Theaccuracyoflaser-inducedbreakdownspectroscopy(LIBS)quantitativemethodisgreatlydependentontheamountofcertifiedstandardsamplesusedfortraining.However,inpracticalapplications,onlylimitedstandardsampleswithlabeledcertifiedconcentrationsareavailable.Anovelsemi-supervisedLIBSquantitativeanalysismethodisproposed,basedonco-trainingregressionmodelwithselectionofeffectiveunlabeledsamples.Themainideaoftheproposedmethodistoobtainbetterregressionperformancebyaddingeffectiveunlabeledsamplesinsemi-supervisedlearning.First,effectiveunlabeledsamplesareselectedaccordingtothetestingsamplesbyEuclideanmetric.Twooriginalregressionmodelsbasedonleastsquaressupportvectormachinewithdifferentparametersaretrainedbythelabeledsamplesseparately,andthentheeffectiveunlabeledsamplespredictedbythetwomodelsareusedtoenlargethetrainingdatasetbasedonlabelingconfidenceestimation.Thefinalpredictionsoftheproposedmethodonthetestingsampleswillbedeterminedbyweightedcombinationsofthepredictionsoftwoupdatedregressionmodels.Chromiumconcentrationanalysisexperimentsof23certifiedstandardhigh-alloysteelsampleswerecarriedout,inwhich5sampleswithlabeledconcentrationsand11unlabeledsampleswereusedtotraintheregressionmodelsandtheremaining7sampleswereusedfortesting.Withthenumbersofeffectiveunlabeledsamplesincreasing,therootmeansquareerroroftheproposedmethodwentdownfrom1.80%to0.84%andtherelativepredictionerrorwasreducedfrom9.15%to4.04%.