简介:利用蒙特卡罗模拟程序MCNP研究了NaI(Tl)探测器对海水中137Cs、131I的比计数率响应情况;计算了NaI(Tl)探测器对不同半径海水球体源中137Cs与131I的比计数率响应曲线;分析了探测器防水套筒、NaI(Tl)晶体尺寸与结构、射线能量等因素对比计数率响应的影响;拟合了3R3型、5R5型NaI(Tl)探测器最大比计数率ymax及有效探测距离D。防水套筒模型与裸晶体简化模型的计算结果对比表明,裸晶体模型会给计算带来明显的偏差,应在模型设计时,考虑探测器结构,构建更精确的模型。
简介:Wegiveaconstructionofthemaximum,andtheminimumofthesetofnondecreasmgapproxmantsinthediscretecase,whereisapositiveconoexfunction.Acharacterizationofthatsetisalsoobtained.
简介:On △I=4 Bifurcation PhenomenaOn△I=4BifurcationPhenomena¥ZhangJingye;YangSunandMikeGuidryTheexperiments-bythenew7--raydetector...
简介:Thispaperstudiestheinteractionofshockandgradientwave(soundwave)ofsolutionstothesystemofinviscidisentropicgasdynamicsasamodelforthecorrespondingproblemsfornonlinearhyperbolicsystems.Theproblemcanbereducedtoaboundaryvalueprobleminawedgeddormain,ByusingthemethodofconstructingasymptoticsolutionsandNewton'siterationprocessitisprovedthatifaweakshockhitsagradientwave,thenthegrandientwavewillsplitintotwogradientwaves,whiletheshockcontinusespropagating.Inthispapertheauthorreducestheproblemtoastandardformandconstructsasymptoticsolutionoftheproblem.Theexistenceofthegenuinesolutionwillhegiveninthefollowingpaper.
简介:Theauthorintroducesanotionofweak1sequencesandcharacterizessuchsequencesbymeansofhomologicalmethods.ThisnotionextendsthenotionofweekM-sequencesandthusextendsthenotionsofgeneralizedCohen-MacaulaymodulesandBuchsbaummodulestomoregeneralcases.
简介:ThemultivariatesplineswhichwerefirstpresentedbydeBooorasacompletetheoreticalsystemhaveintriguedmanymathematicianswhohavedevotedmanyworksinthisfieldwhichisstillintheprocessofdevelopment.Theauthorofthispaperisinterestedintheareaofinter-polationwithspecialemphasisontheinterpolationmethodsandtheirapproximationorders.ButsuchB-splines(bothunivariateandmultivariate)donotinterpolateddirectly,soIap-proachedthisprobleminanotherwaywhichistoextendmyinterpolatingsplineofdegree2n-1inunivariatecase(See[7])tomultivariatecase.Iselectedtriangulatedregionwhichisinspiredbyothermathematicians’works(e.g.[2]and[3])andextendtheinterpolatingpolynomialsfromunivariatetom-variatecase(See[10])Inthispapersomeresultsinthecasem=2arediscussedandprovedinmoreconcretedetails.Basedonthesepolynomials,theinterpolatingsplines(itisdefinedbymeaspiecewisepolynomialsinwhichtheunknownpar-tialderivativesaredeterminedundercertaincontinuousconditions)arealsodiscussed.Theapproximationordersofinterpolatingpolynomialsandofcubicinterpolatingsplinesareinverstigated.Welunitedourdiscussionontherectangulardomainwhichispartitionedintoequalrighttriangles.Astothecaseinwhichtherectangulardomainispartitionedintounequalrighttrianglesaswellasthecaseofmorecomplicateddomains,wewilldiscussinthenextpa-per.
简介:TheauthorsconsiderthemultilinearoscillatorysingularintegraloperatordefinedbyTA1,A2,…,Akf(x)=∫R^ne^ip(x,v)k/∏/j=1Rmi(Ajix,y)(Ω(x-y))/(│x-y│^n+M)f(y)dy,whereP(x,y)isareal-valuedpolynomialonR^n×R^n,Ωishomogeneousofdegreezero,Rmj(Aj;x,y)denotesthemj-thorderTaylorseriesremainderofAjatxexpandedabouty,M=k/∑j=1mj,ItisshownthatifΩbelongstothespaceLlog^+L(S^n-1)andhasvanishingmomentuptoorderM,then‖TA1,A2,…,Akf‖q≤ck/∏/j=1(∏/│α│=mj‖D^αAj‖rj)‖f‖p,providedthat1