学科分类
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259 个结果
  • 简介:ThispaperdiscussesthesolutionsofthelinearmatrixequationBTXB=Donsomelinearmanifolds.Somenecessaryandsufficientconditionsfortheexistenceofthesolutionandtheexpressionofthegeneralsolutionaregiven.Andalsosomeoptimalapproximationsolutionsarediscussed.

  • 标签: 半定解 线性矩阵方程 线性流形 半定矩阵 正交矩阵
  • 简介:逃逸时间算法是生成Mandelbrot集(简称M集)最常用的算法,本文针对非线性复映射f(z)=z^m+c为迭代函数的情形进行讨论.首先.根据逃逸时间算法的基本原理给出相应的算法步骤;然后,对迭代函数f(z)=z^m+c进行了详细研究,从而合理地确定了算法中需要控制的变量B(参数值c0的取值范围)的取值,这样就大大地减少了迭代次数,从而提高了算法的运算效率.

  • 标签: MANDELBROT集 逃逸时间算法 控制变量 迭代函数
  • 简介:研究了线性空间C[a,b]上的线性相关性,给出了衡量C[a,b]上n个函数线性相关性程度的量以及线性相关的充分必要条件.

  • 标签: | 线性相关性 内积矩阵 最小特征根
  • 简介:Inthiswork,DSCandSEMstudiesindicatethation-ligandinteractioncanbeutilizedtoenhancetheinteractionofpoly(styrene-block-2-vinylpyridine)[P(S-b-2VP)]andpolyethylenebasedionomer(Surlyn).Thecompatibilityforthisblendingsystemcanbeimprovedbythisspecialinteractionand20/80wtistheoptimumblendingcompositionwithgoodcompatibility.FTIRresultsfurthercertifythatstronginteractionsexistintheblendingsystem.

  • 标签: 聚(苯乙烯-B-2-乙烯基嘧啶) 相容性 离子交联聚合物 离子配位键交互作用.
  • 简介:TwoseriesofterritremBanalogues(10a-10cand18)havebeendesignedandsynthesizedfromjujubogenin5awhichwaspreparedfromjujubogeninglycosides5bobtainedfromtheleavesofZizyphusjujuba.Thestructuresofthenewcompoundswereconfirmedby1H-,13C-NMRandMSdata.Compounds10cand18showedweakinhibitoryeffectonAChEat10^-4mol/E.

  • 标签: 合成 2-内-l-安息香酸盐 TerritremB相似物 Jujubogenin 配糖基 药物提取
  • 简介:在Zeng等人对有界变差函数f的Durrmeyer-Bézier算子在区间(0,1)上收敛于(1/(α+1))f(x+)+(α/(α+1))f(x-)的收敛阶进行研究的基础上,利用基函数的概率性质等方法,对其所给的Durrmeyer-Bézier算子收敛阶估计结果作进一步的改进,得到其收敛阶的精确估计.

  • 标签: Durrmeyer-Bézier算子 有界变差函数 收敛阶 系数估计
  • 简介:Invariantsubspacemethodisexploitedtoobtainexactsolutionsofthetwocomponentb-familysystem.Itisshownthatthetwo-componentb-familysystemadmitsthegeneralizedfunctionalseparablesolutions.Furthermore,blowupandbehaviorofthoseexactsolutionsarealsoinvestigated.

  • 标签: 分离变量 双组分 不变子空间 系统 泛函 广义
  • 简介:Thereisagrowingsupportforthelowlyingscalarmesonsf0(500),f0(980),a0(980),and(800)tobegenerateddynamicallyfromtheinteractionofpseudoscalarmesons,whilethecaseofthenextsetofscalarresonancesathigherenergies,f0(1370),f0(1710),K0(1430)ismoreaquestionofdebate.Soisthecaseofthetensorresonancesf2(1270),f′2(1525),K2(1430).AnewperspectiveonthesestateshasbeenofferedinRef.[1]wherethef0(1370)andf2(1270)resonancesareshowntobegeneratedfromtheinteractionprovidedbythelocalhiddengaugeLagrangiansimplementingunitarization.Itisshownthattheideaofthenatureofthesestatesasvectormeson-vectormesoncompositestateshasbeentestedinmanyreactions.Yet,thepermanentdiscussionoftheissuedemandsextrachecksforotherobservablesand,inthissense,theweakdecaysbringanewsourceofvaluableinformationthatshouldservetotestdifferentmodels.

  • 标签: J/Ψ source case SENSE NEXT IDEA
  • 简介:Kineticsofchloride/sulfate,chloride/nitrateandnitrate/sulfateforwardexchangesandreverseexchangesatsolutionconcentrationsof1N,0.2Nand0.02Non201×7strongbaseanionexchangeresin,respectively,havebeenexaminedat25℃.Itisfoundthattheforwardandthereverseexchangeratesofthetwogivenionsatlowsolutionconcentration,respectively,underidenticalconditionscanbecontrolledbydifferentmechanisms,whilethoseathighsolutionconcentrationareallcontrolledbyparticlediffusion.Theternaryexchangeratesofsulfate/(chloride+nitrate)andnitrate/(chloride+sulfate)havealsobeenexamined.

  • 标签: 二元离子交换 硫酸根-氯离子-硝酸根离子-201×7体系 三元离子交换 动力学
  • 简介:Hightimeresolutionmeasurementsoftheelectrostaticfluctuations,radialelectricfieldErandturbulence-inducedelectronfluxΓehavebeenperformedacrossthetransitionoflowerhybridcurrentdriveimprovedconfinementwithagraphiteLangmuirprobearrayatthelastclosedfluxsurfaceoftheHT-7tokamak.ThedecreaseofΓeisdominatedbythesuppressionoffluctuationlevels,whichfollowsthechangeofEr.AreversalofthepoloidalpropagationdirectionofturbulencedemonstratesthatthepoloidalpropagationisdominatedbyEr×Bφdrift.Theenhancementofpoloidalcoherenceaccompaniesthefluctuationsuppression,whichsuggeststhesubtlevariationofturbulencefeatures.

  • 标签: 等离子体 TOKAMAK 封闭磁通面
  • 简介:Dithia-monoaza18-Crown-6anditsimmobilizationproduct,silica-bound1,7-dithia-4-aza-10,13,16-trioxa-cyclooctadecaneviaaspacerofthreecarbonatoms,anditsplatinumcomplexhavebeensynthesized.Itisfoundthattheplatinumcomplexisanefficienthydrosilylationcatalystforolefins.TheXPSdataoftheplatinumcomplexarereported.

  • 标签: 二氧化硅 铂络合物 铂配合物 1 7-硫-4-氮杂-10 13 16-氧硫杂环十八烷
  • 简介:InsituhighpressureenergydispersiveX-raydiffractionmeasurementsonlayeredperovskite-likemanganateCa3Mn2O7underpressuresupto35GPahavebeenPerformedbyusingdiamondanvilcellwithsynchrotronradiation.Theresultsshowthatthestructureoflayeredperovskite-likemanganateCa3Mn2O7isunstableunderpressureduetotheeasycompressionofNaCl-typeblocks.ThestructureofCa3Mn2O7underwenttwophasetransitionsunderpressuresintherangeof0-35GPa.Onewasatabout1.3GPawiththecrystalstructurechangingfromtetragonaltgoorthorhombic.Theotherwasatabout9.5GPawiththecrystalstructurechangingformorthorhombicbacktoanothertetragonal.

  • 标签: 高压 X射线衍射 Ca3Mn2O7 钙钛矿结构 锰酸盐晶体 相变
  • 简介:Aseriesofethyl6-alkoxy-7-phenyl-4-hydroxy-3-quinolinecarboxylatesweredesignedandsynthesized.Theirstructureswereconfirmedby~1HNMR,~(13)CNMR,IRandHRMS.ThebiologicalactivitieswereprimarilyevaluatedagainstEimeriatenellaaccordingtoAnticoccidialIndex(ACI)methodinvivo.Theresultsshowedthatcompounds5e,5fand5iexhibitedanticoccidialactivitiesagainstE.tenellaat27mgkg~(-1).

  • 标签:
  • 简介:(八)统计初步目标测试(B)(满分100分,45分钟完成)一、填空:(共50分,每小题5分)1、为了了解某校初二年级女生400米跑的成绩,从中抽查了50名女生400米跑的成绩进行分析,在这个问题中,是总体,是总体的一个样本,是个体,是样本容量。2、样...

  • 标签: 样本容量 初中毕业生 样本标准差 样本数据 算术平均数 样本方差
  • 简介:Inthispaper,blendmembranesfrompolyvinylacetate(PVAc)andblockcopolymerpoly(amide-12-b-ethyleneoxide)(Pebax1074)arepreparedbysolutioncastingandsolventevaporationmethod.Althoughtheyarehomogeneousonamacro-scale,theobservationsfromDSCandSEMindicatemicro-phaseseparationforPVAc/Pebax1074blendmembranes.WiththeincreaseofPebax1074content,gaspermeabilitiesofCO2,H2,N2andCH4allincreasegreatly.PVAc/Pebax1074blendmembraneswithhighPVAccontentareappropriateforCO2/CH4separation.Thetemperaturedependenceofgaspermeabilityisdividedintorubberyregionandglassyregion.Theactivationenergiesofpermeationinrubberyregionaresmallerthanthoseinglassyregion,andtheyalldecreasewithincreasingPebax1074content.ForN2,H2andCH4,theirgaspermeationpropertiesaremainlyinfluencedbythedual-modesorptionandhydrostaticpressureeffect.ButforCO2,itspermeabilityincreaseswiththeincreaseofpressureduetoCO2-inducedplasticizationeffect,whichismoreobviousforPVAc/Pebax1074blendmembraneswithhighPVAccontent.

  • 标签: polyvinyl acetate poly(amide-12-b-ethylene oxide) blend membrane