简介：Thispaperpresentsalternatingdirectionfinitevolumeelementmethodsforthree-dimensionalparabolicpartialdifferentialequationsandgivesfourcomputationalschemes,oneisanalogoustoDouglasfinitedifferenceschemewithsecond-ordersplittingerror,theothertwoschemeshavethird-ordersplittingerror,andthelastoneisanextendedLODscheme.TheL2normandH1semi-normerrorestimatesareobtainedforthefirstschemeandsecondone,respectively.Finally,twonumericalexamplesareprovidedtoillustratetheefficiencyandaccuracyofthemethods.

简介：Thispaperdealswiththeasymptoticstabilityanalysisofθ-methodsformultipantographdelaydifferentialequation{ú(t)=λu(t)+∑↑ιi=1μiu(qit),0

简介：这份报纸开发一个新方法在二和三种尺寸在矩形的格子上分析有限元素方法的重申的缺点修正计划的集中。主要想法是提出精力内部的产品和精力(半)标准进矩阵形式。然后，包含的二关键不平等的二个常数是min，二的最大特征值分别地联系概括特征值问题。这二个概括特征值问题的元素水平上的本地版本确切被解决突然地获得(更低)这二个常数的上面的界限。这和为重申的答案的一些必要观察在减少的2D和单调建立集中在3D的性质。为二种尺寸，结果此处在文学改进那些；为三种尺寸，结果此处是新的。数字结果被介绍检验理论结果。[从作者抽象]

简介：Inthispaper,weconsiderlowerorderrectangularfiniteelementmethodsforthesin-gularlyperturbedStokesproblem.ThemodelproblemreducestoalinearStokesproblemwhentheperturbationparameterislargeanddegeneratestoamixedformulationofPois-son'sequationastheperturbationparametertendstozero.Weproposetwo2Dandtwo3Dnonconformingrectangularfiniteelements,andderiverobustdiscretizationerrorestimates.Numericalexperimentsarecarriedouttoverifythetheoreticalresults.

简介：Theboundaryelementmethod(BEM)isamainmethodforanalyzingtheinteractionsbetweenthewavesandthemarinestructures.AswiththeBEM,asetoflinearequationsaregeneratedwithafullmatrix,therequiredcalculationsandstorageincreaserapidlywiththeincreaseofthestructurescale.Thus,anacceleratedmethodwithalowstorageisdesirableforthewaveinteractionwithaverylargestructure.AsystematicreviewisgiveninthispaperfortheBEMforsolvingtheproblemofthewaveinteractionwithalargescalestructure.VariousintegralequationsarederivedbasedondifferentGreenfunctions,theadvantagesanddisadvantagesofdifferentdiscretizationschemesoftheintegralequationsbytheconstantpanels,thehigherorderelements,andthesplinefunctionsarediscussed.Forthehigherorderelementdiscretizationmethod,thespecialconcernsaregiventothenumericalcalculationsofthesingle-layerpotential,thedoublelayerpotentialandthesolidanglecoefficients.Foralargescalecomputationproblemsuchasthewaveinteractionwithaverylargestructureoralargenumberofbodies,theBEMswiththeFMMandpFFTaccelerationsarediscussed,respectively,includingtheprinciplesoftheFMMandthepFFT,andtheirimplementationsinvariousintegralequationswithdifferentGreenfunctions.Finally,somepotentialapplicationsoftheaccelerationmethodsforproblemswithlargescalecomputationsintheoceanandcoastalengineeringareintroduced.

简介：CO2emissionofthesteelindustrytakesupagreatproportionofthetotalemissionoftheworld.ItisnecessarytoreducetheCO2intensityofsteelproductsinordertosaveenergy,protecttheenvironmentandkeepasustainabledevelopmentinthesteelindustry.Basedontheresearchofsteelproducts'lifecycleinventory,thosewhoconductedthisresearchhavefocusedontheanalysisofCO2emissionfactorsandmeasures.Adoptingthelifecycleinventorymodelofacertainsteelmakingsite,togetherwiththeTornadoChart,theresearchershaveidentifiedsignificantfactors,providedsomeexplanation,andsuggestedsomepossiblemeasurestoreduceCO2emission.TheresultshaveshownthatthemostimportantfactorsaretheCO2intensityofblastfurnacegas(BFG),hotmetalratioofbasicoxygenfurnace(BOF)andthematerialutilizationefficiency.Accordingly,somemeasuressuchasremovingCO2inBFG,decreasingthehotmetalproportioninBOF,andimprovematerialutilizationefficiencyineachprocess,maybetakentodecreaseCO2emission.

简介：Inthispaperweimprovethetwoversionsofthetwo-sidedprojectedquasi-Newtonmethod-onewasproposedbyNocedal&Overtonin[1]andtheotherwasdiscussedinourpreviouspaper,byintroducingthreedifferentmeritfunctionstomakeinexactone-dimensionalsearches.Itisshownthattheseimprovedquasi-Newtonalgorithmshavegainedglobalconvergencepropertywhichisnotpossessedbytheoriginaltwoalgorithms.

简介：Twomethodsforimprovingtheequidrivingpower-frequencycharacteristicsofbroad-bandhighpowerklystronsarepresented.Oneisthatacomb-linebandpassfilterwithsomeattenuationpropertiesisinsertedbetweentheTWTdriverandtheklystronforcompensatingthegain-frequencycharacteristicsoftheklystrontogettherequiredequidrivingpower-frequencycharacteristics.Theotheristhatareactiveelementisconnectedwiththeinputcavitytochangeitsresonancefrequenciesf0andQL,andthustoimprovethepower-frequencycharacteristicsoftheklystron.

简介：金属涂的cenospheres广泛地在工业被使用了。不同涂层方法导致不同典型金属电影。由化学涂层的cenosphere上的金属电影不看起来很光滑，展出积累的金属和表面上的大头针洞并且离开某点uncoated。同时，金属电影紧没被吸收到cenospheres上并且是容易的开脱皮。然而，磁控管劈啪作响准备的金属电影是紧缩的，光滑并且在大头针洞外面。这部电影有好亲密关系到cenosphere表面。甚至当cenosphere被压碎时，如此的电影不用它分开。两个都，金属电影给一样的XRD模式，显示金属的水晶结构由这二个方法拍摄是一样。化学涂层是一个复杂过程并且有害环境，而是它适合极其细小的粉末涂层(粒子尺寸能是不到2)。磁控管劈啪作响的方法是环境的友好并且快速工作，但是这个方法要求特殊设计的设备并且不为极其细小的粉末工作。如果粒子尺寸是不到30，涂层过程是难的继续。

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简介：在这篇论文，一个不连续的有限元素方法为积极、对称，一阶的夸张系统(稳定、非稳定的状态)被使用线性三角元素构造并且分析，并且最佳的错误估计的O(h2)顺序为准确答案在强烈常规的三角测量和H3整齐的假设下面被导出。集中分析基于插值近似的一些超级靠近的估计。最后，我们在一个二维的领域讨论马方程，并且数字实验被给验证理论结果。

简介：Thispapergivesthedirectivityfunctionofasectoralmul-ti-elementcylinderarray,analyzeitsphasefactor,explainindetailthesideloberejectionbyselectingthenumberofelements,bafflingandamplitudeweighting.Theyareparticularlyusefulfordirectionaltrackingofacousticalsignalandtargetlocating.

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简介：云在红外线的发光传播上有重要效果因为在数据吸收的云效果的包括不能仅仅极大地改进吸收大气的参数的质量，而且由调整红外线的发光数据的部分最小化云参数的起始的错误。根据Grapes-3D-var(全球、地区性的吸收和预言提高了系统)，云液体水，云冰水和云盖子在吸收作为管理变量被增加。在晴朗天空，部分多云的盖子和完全多云的盖子的条件下面，16条MODIS隧道的亮度温度在理想的测试分别地被吸收。结果看那模仿的背景亮度温度什么时候比观察低，分析的地将由增加它的温度并且减少它的潮湿，云液体水，云冰水，和云增加模仿的亮度温度盖子。如果调整在矛盾的方向被做，模仿的亮度温度能被减少。在晴朗天空条件下面的温度和特定的湿度的调整一致很好到MODIS的设计隧道，而是它在云层下面为层次被削弱。理想的测试由同时作为在红外线的发光的吸收期间管理变量增加云参数和大气的参数表明那，云参数和大气的参数能用观察红外线的发光和常规气象学的元素被调整充分利用红外线的观察。

简介：1.IntroductionConsidertheinitialvalueproblemwhichisassumedtohaveauniquesolutiony(t)ontheinterval[0,+co).Forsolving(1.1),considerthes--stageimplicitRunge-Kutta(IRK)methodandthes-stagemono-implicitRunge-Kutta(MIRK)method{2,51swhereh)0isthestepsize,hi,c...

简介：Drylandsareamongthoseregionsmostsensitivetoclimateandenvironmentalchangesandhuman-inducedperturbations.Themostwidelyaccepteddefinitionofthetermdrylandisaratio,calledtheSurfaceWetnessIndex(SWI),ofannualprecipitationtopotentialevapotranspiration(PET)beingbelow0.65.PETiscommonlyestimatedusingtheThornthwaite(PETTh)andPenman–Monteithequations(PETPM).ThepresentstudycomparedspatiotemporalcharacteristicsofglobaldrylandsbasedontheSWIwithPETThandPETPM.ResultsshowedvastdifferencesbetweenPETThandPETPM;however,theSWIderivedfromthetwokindsofPETshowedbroadlysimilarcharacteristicsintheinterdecadalvariabilityofglobalandcontinentaldrylands,exceptinNorthAmerica,withhighcorrelationcoefficientsrangingfrom0.58to0.89.Itwasfoundthat,during1901–2014,globalhyper-aridandsemi-aridregionsexpanded,aridanddrysub-humidregionscontracted,anddrylandsunderwentinterdecadalfluctuation.Thiswasbecauseprecipitationvariationsmademajorcontributions,whereasPETchangescontributedtoamuchlesserdegree.However,distinctdifferencesintheinterdecadalvariabilityofsemi-aridanddrysub-humidregionswerefound.ThisindicatedthattheinfluenceofPETchangeswascomparabletothatofprecipitationvariationsintheglobaldry–wettransitionzone.Additionally,thecontributionofPETchangestothevariationsinglobalandcontinentaldrylandsgraduallyenhancedwithglobalwarming,andtheThornthwaitemethodwasfoundtobeincreasinglylessapplicableunderclimatechange.

简介：ＤｅｔｅｒｍｉｎａｔｉｏｎｏｆＤｉｆｆｕｓｉｏｎＣｏｅｆｆｉｃｉｅｎｔｏｆＡｃｔｉｖｅＣｏｍｐｏｎｅｎｔｉｎＬｉｑｕｉｄＡｌｌｏｙｗｉｔｈＭｏｌｔｅｎＳａｌｔＥｌｅｃｔｒｏｃｈｅｍｉｃａｌＭｅｔｈｏｄｓＤｕＳｅｎｌｉｎａｎｄＳｕＭｉｎｇｚｈｏｎｇ（杜...

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简介：Inthispaperweproposeaspectralelement:vanishingviscosity(SEW)methodfortheconservationlawsonthesemi-infiniteinterval.Byusingasuitablemapping,theproblemisfirsttransformedintoamodifiedconservationlawinaboundedinterval,thenthewell-knownspectralvanishingviscositytechniqueisgeneralizedtothemulti-domaincaseinordertoapproximatethistrarsformedequationmoreefficiently.Theconstructiondetailsandconvergenceanalysisarepresented.Underausualassumptionofboundednessoftheapproximationsolutions,itisproventhatthesolutionoftheSEWapproximationconvergestotheuniciueentropysolutionoftheconservationlaws.Anumberofnumericaltestsiscarriedouttoconfirmthetheoreticalresults.

简介：TheHermitianandskew-Hermitiansplitting(HSS)methodisanunconditionallyconvergentiterationmethodforsolvinglargesparsenon-Hermitianpositivedefinitesystemoflinearequations.BymakinguseoftheHSSiterationastheinnersolverfortheNewtonmethod,weestablishaclassofNewton-HSSmethodsforsolvinglargesparsesystemsofnonlinearequationswithpositivedefiniteJacobianmatricesatthesolutionpoints.ForthisclassofinexactNewtonmethods,twotypesoflocalconvergencetheoremsareprovedunderproperconditions,andnumericalresultsaregiventoexaminetheirfeasibilityandeffectiveness.Inaddition,theadvantagesoftheNewton-HSSmethodsovertheNewton-USOR,theNewton-GMRESandtheNewton-GCGmethodsareshownthroughsolvingsystemsofnonlinearequationsarisingfromthefinitedifferencediscretizationofatwo-dimensionalconvection-diffusionequationperturbedbyanonlinearterm.ThenumericalimplementationsalsoshowthataspreconditionersfortheNewton-GMRESandtheNewton-GCGmethodstheHSSiterationoutperformstheUSORiterationinbothcomputingtimeanditerationstep.