学科分类
/ 25
500 个结果
  • 简介:ThispapersolvesanopenproblemofVaserstein.Themainresultis:theequationx^m+y^m=z^mhasasolutioninSL2zifandonlyifmisnotdivisibleby4or6andmisnotcongruentto3modulo6.

  • 标签: 数论 矩阵 FERMAT大定理 实数解
  • 简介:Synchrotronradiationsmall-angleX-rayscattering(SAXS)andtheviscositytechniquewereusedtoinvestigatetheeffectofdissolvedCO2intolueneontheconformationofpolystyrene(PS)inthesolution.TheviscosityofPSsolutiondecreasesfasterwithincreasingantisolventCO2pressurethanthatofthesolventintheabsenceofthepolymer.theintrinsicviscosity[η]calculatedusingthewellknownHugginsequationdecreaseswithantisolventpressure.ItwasfoundthatthesecondvirialcoefficientA2andtheapparentmean-squareradiusofgyration^1/2decreaseswithpressureofantisolventCO2.AllthesephenomenacanbeattributedtotheshrinkofPSchaininthecourseofaddingthegasantisolventbecausetheintercationbetweenthepolymerandsolventbecomesweaker.Thevalues^1/2atdifferentpressuresobtainedfromSAXSdataagreereasonablywiththosecalculatedfromFlorytheoryusingtheviscositydatadeterminedinthiswork.ThisimpliesthatFlorytheory,whichhasbeenusedwidelyforthesolutionsofpolymersinliquidsolvents,isalsoapplicabletothepolymersolutionwithgasantisolvent.

  • 标签: 小角X射线散射分析 聚苯乙烯 结构分析 SAXS 甲苯 同步加速器
  • 简介:运用离散变分Xα方法对双核金属酞菁(M=V2+、Cr2+、Mn2+、Fe2+、Co2+、Ni2+、Cu2+、Zn2+等)系列化合物进行了量子化学研究,得到了其费米能级。总态密度、前线轨道布居等,讨论了它们的催化活性。

  • 标签: DV-X_α法 费米能级 总态密度 前线轨道布居分析
  • 简介:ForquadraticnumberfieldsF=Q(√2pl…pt-1)withprimespj≡1mod8,theauthorsstudytheclassnumberandthenormofthefundamentalunitofF.TheresultsgeneralizenicelywhathasbeenfamiliarforthefieldsQ(√2p)withaprimep≡1mod8,includingdensitystatements.Andtheresultsarestatedintermsofthequadraticformx2+32y2andillustratedintermsofgraphs.

  • 标签: 古典群 雷代矩阵 二次数域 素数 初级子群
  • 简介:在介绍B.VANROOTSELAAR的解方程组x′=Ax的一种新方法的基础上,对矩阵F(0)求法作了补充,对照以往通常的解法,分析了它的优越性.文章用完全开放性的Maple语言程序在计算机上实现了这种方法的应用,并通过生动的例子说明了同样是借助计算机强大的计算功能,新的解法在速度上要提高上百倍,更有实用价值.

  • 标签: 向量微分方程 特征值 Wronskian矩阵 基解矩阵 Maple程序
  • 简介:拉制金属表被合拢与11%变硬工作。这些随后被使用,抵抗焊接构造X类型格子捆绑有0.17的核心亲戚密度的三明治面板。三明治面板在单轴的压缩被测试,为比较,有限元素的方法被采用模仿测量压缩压力紧张曲线。山峰压缩力量比金字塔形的核心三明治的高是32%。变硬工作的X类型格子结构的提高的机械性质主要与弯曲并且工作变硬的低度从直神气的贡献发源,而非二维的蹒跚的节点。

  • 标签: 加工硬化 桁架结构 压缩性能 X型 模拟 实验
  • 简介:Inthisarticle,wetaketheX(5568)asthediquark-antidiquarktypetetraquarkstatewiththespin-parityJ~P=0~+,constructthescalar-diquark-scalar-antidiquarktypecurrent,carryouttheoperatorproductexpansionuptothevacuumcondensatesofdimension-10,andstudythemassandpoleresidueindetailswiththeQCDsumrules.WeobtainthevalueM_X=(5.57±0.12)GeV,whichisconsistentwiththeexperimentaldata.ThepresentpredictionfavorsassigningtheX(5568)tobethescalartetraquarkstate.

  • 标签: QCD求和规则 双夸克 标量 模型 自旋宇称 真空凝聚
  • 简介:在脉冲X射线测量中,当出射X射线粒子总数低于108时,通过闪烁体成像测量角分布的方法难以获得结果。提出了一种将准直孔阵列、快时间响应闪烁体和多路延时光纤相结合的电流型测量方法,通过记录不同角度的瞬时脉冲波形,能够实现ns以下小焦斑快脉冲X射线角分布的测量。基于该方法研制的测量系统在亚ns重复频率快脉冲硬X射线源上进行了实验验证,获得了距源20cm处的角分布数据。

  • 标签: 脉冲X射线 角分布 闪烁体 光纤
  • 简介:主要考虑11维Boussinesq系统的一个Darboux变换,反复利用该Darboux变换,可以从该系统的一个已知解出发,通过代数运算和求导运算得到系统的新解.

  • 标签: 1+1维Boussinesq系统 可积系统 DARBOUX变换
  • 简介:Theinsertionof1,1-bis(1′-naphthyl)ethylenemonomerunitintotheactivepolystyrenechainendgreatlydecreasedthereactivityoftheactivechainendtothecarbonylgroup,andallowedthepolymericchainendtoreactonlywiththedoublebondinN-methacryloylcaprolactam,resultinginN-acylcaprolactamfunctionalizedpolystyrenein100%conversion.Newdiblockcopolymerofpolystyrenewithpolycaprolactamwassynthesizedbydirectreactionofthefunctionalizedpolymerwithcaprolactamwithoutaddingadditionalalkalimetalortheircaprolactamsalts.

  • 标签: 1 1-bis (1’ -naphthyl) ETHYLENE N-methacryloylcaprolactam
  • 简介:Aseriesofnovel1H-benzimidazol-1-ylacetatesand1H-benzimidazol-1-ylpropionatescontaining1H-1,2,4-triazolemoietyweresynthesizedundermicrowaveirradiationbymulti-stepreactions,inyieldsof87-94%.TheirinvitroantifungalactivitiesagainstBotrytiscinereaandSclerotiniasclerotiorumwereevaluatedbymycelialgrowthratemethod.AllthetargetcompoundsexhibithighactivitiesagainstB.cinereawiththeEC50valuesof7.96-21.74μg/mL,higherthanthatofcarbendazim.

  • 标签: 抗真菌活性 苯并咪唑 乙酸酯 体外 合成 基团
  • 简介:<正>Inthispaper,weapplythesolitontheorytothecaseofisometricimmersionindifferentialgeometryandobtainafamilyofisometricimmersionsfromMn1(c1)×Mn2(c2)tospaceformsMn(c)byintroducing2-parameterloopalgebra.

  • 标签: SOLITON THEORY ISOMETRIC immersion Riemaniann product
  • 简介:Anewseriesofliquidcrystalscomprisingeightheterocyclicisoflavoneesters,7-alkanoyloxy-3-[4’-(3-methylbutyloxyphenyl)]-4H-1-benzopyran-4-onesexhibitingenantiotropicnematic(N)andsmecticC(SmC)phasesweresynthesizedandinvestigated.Themesomorphicpropertiesofallderivativeswereinvestigatedbymeansofdifferentialcalorimetryandpolarizedopticalmicroscopy.WideangleX-raydiffractiontechniquewasemployedtoinvestigatethemolecularpackingassociatedwiththeintermolecularinteractionaswellasthecorrelationbetweenthethermalbehaviourofthesecompoundswiththeiranisotropypropertieswithinamesophase.

  • 标签: X射线衍射技术 黄酮衍生物 合成 杂环 液晶 表征