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397 个结果
  • 简介:根据超外差接收机原理和数字锁相环原理,简单介绍CD2003和MB1504的特性与基本用法,并给出一个应用该器件制作超外差调频接收机的具体设计方案。

  • 标签: 超外差 锁相环 调频 二次变频
  • 简介:InthispaperL^p-L^qestimatesforthesolutionu(x,t)tothefollowingperturbedhigh-erorderhyperbolicequationareconsidered,(ρπ--a△)(ρπ--b△)u+V(x)u=O,x∈R^n,n≥6,ρ1eu(x,O)=O,ρ^3eu(x,O)=f(x),(j=O,1,2).WeassumethattheotentialV(x)andtheinitialdataf(x)arecompactlysupported,andV(x)issufficientlysmall,thenthesolutionu(x,t)oftheaboveproblemsatisfiesthesameL^p-L^qestimatesasthatoftheunperturbedproblem.

  • 标签: L^p-L^q估计 高阶分支 双曲型偏微分方程 紧支撑
  • 简介:<正>InthispaperitisprovedthatforallcompletelydistributivelatticesL.thecategoryofL-fuzzifyingtopologicalspacescanbewmbeddedinthecategoryofL-topologicalspaces(stratifiedChang-Goguenspaces)asasimultaneouslybireflectiveandbicoreflectivefullsubcategory.

  • 标签: L-topological SPACE L-fuzzifying TOPOLOGICAL SPACE TOPOLOGICAL
  • 简介:WeconstructaclassofintegrablegeneralizationofTodamechanicswithlong-rangeinteractions.ThesesystemsareassociatedwiththeloopalgebrasL(Cr)andL(Dr)inthesensethattheirLaxmatricescanberealizedintermsofthec=0representationsoftheaffineLiealgebrasCr(1)andDr(1)andtheinteractionspatterninvolvedbearsthetypicalcharactersofthecorrespondingrootsystems.WepresenttheequationsofmotionandtheHamiltonianstructure.Thesegeneralizedsystemscanbeidentifiedunambiguouslybyspecifyingtheunderlyingloopalgebratogetherwithanorderedpairofintegers(n,m).Itturnsoutthatdifferentsystemsassociatedwiththesameunderlyingloopalgebrabutwithdifferentpairsofintegers(n1,m1)and(n2,m2)withn2<n1andm2<m1canberelatedbyanestedHamiltonianreductionprocedure.Forallnontrivialgeneralizations,theextracoordinatesbesidesthestandardTodavariablesarePoissonnon-commute,andwheneithernorm≥3,thePoissonstructurefortheextracoordinatevariablesbecomessomeLiealgebra(i.e.theextravariablesappearlinearlyontheright-handsideofthePoissonbrackets).Inthequantumcase,suchgeneralizationswillbecomesystemswithnoncommutativevariableswithoutspoilingtheintegrability.

  • 标签: 广义Toda力学 多体系统 泊松括号 非线性偏微分方程
  • 简介:对采用全自动凯氏定氮仪测定干旱区土壤全氮量的方法以及实验中影响因素进行了研究,对消解时间和硫酸用量进行了选择性实验,结果表明,土壤中有机物在30min时消解完全,硫酸用量在10~15mL时为最佳,干旱区土壤中氮一般含量为(0.260±0.003)%(P=0.95).方法的相对标准偏差(RSD)≤1%,用来测定硫酸铵标准物质,其检测结果与标准值基本吻合,检测的准确度和精密度都符合国家标准的要求.

  • 标签: 全自动凯氏定氮仪 全氮 方法改良 干旱区
  • 简介:Weconsiderforafixedμ,theclassofpolynomialsPn,μ,s:=P(z)=zsanzn-s+n-s∑j=μan-jzn-j-s;1≤μ≤n-sofdegreen,havingallzerosin|z|≤k,k≤1,withs-foldzerosattheorigin.Inthispaper,wehaveobtainedinequalitiesinthereversedirectionfortheaboveclassofpolynomials.Besides,extensionsofsomeTuran-typeinequalitiesforthepolarderivativeofpolynomialshavebeenconsidered.

  • 标签: 空间 多项式 NS NJS 不等式 原点
  • 简介:AnefficientroutetoprepareL-glucoseandL-galactoseisdescribed.TheL-sugarsareachievedbyusingthestrategyofswitchingthefunctionalgroupsatC1andC5ofD-glucoseandD-mannose.TheoxidationandreductionofthesilylenoletheratC1andthelead(IV)tetraacetatemediatedoxidativedecarboxylationatC5arethekeysteps.L-GlucoseandL-galactosearepreparedinaconvenientandinexpensiveway.

  • 标签: 半乳糖衍生物 D-葡萄糖 左旋 合成 D-甘露糖 甲硅烷基
  • 简介:Lp-LqdecayestimateofsolutiontoCauchyproblemofalinearthermoviscoelasticsystemisstudied.Byusingadiagonalizationargumentoffrequencyanalysis,thecoupledsystemwillbedecoupledmicrologically.Thenwiththehelpoftheinformationofcharacteristicrootsforthecoefficientmatrixofthesystem,Lp-LqdecayestimateofparabolictypeofsolutiontotheCauchyproblemisobtained.

  • 标签: 系统问题 柯西问题 衰变估计 CAUCHY问题 衰减估计 频率分析
  • 简介:1.IntroductionInthispaperweconsiderCauchyproblemforaclassofnonhomogeneousNavier-Stokesequationsintheinfinitecylinderwith.Givensatisfyinginthedistributionsensediv,weseekasolutionvectorandapressurefunctionP(t,x)suchthatwhereisanonlinearvector-valuedfun...

  • 标签: ADMISSIBLE triple NAVIER-STOKES equations CAUCHY problem
  • 简介:Inthispaper,asimplebutinherentrelationbetweentheL-integralandtheBueeknerworkconjugateintegralisprovedforcrackproblemsinisotropic,anisotropic,anddissimilarmateri-als,respectively.Itisfoundthat,intheabove-mentionedthreecases,theL-integral,fromthemath-ematicalpointofviewaswellasinprinciple,arisesfromBetti’sreciprocaltheorem.ThismeansthattheBuecknerworkconjugateintegralisamoregeneralpath-independentintegralthantheotherssinceanyotherpath-independentintegralscouldbederivedbyusin8theBuecknerintegralwhilechoosingadifferentsubsidiarystress-displacementfield.

  • 标签: INTEGRAL work CONJUGATE INTEGRAL crack SUBSIDIARY
  • 简介:采用湿法消解对不同地区不同深度的土壤进行前处理,在最佳的实验条件下,应用原子荧光光谱法测定砷和汞的含量,测定的相对标准偏差As为1.4%~2.3%,Hg为2.0%~3.5%,加标回收率As为91%~106%,Hg为96%~102%.方法操作简单、快速,检出限、准确度均能满足土壤环境样品检验的要求.

  • 标签: 土壤 原子荧光光谱法
  • 简介:We’llstudytheFEMforamodelforcompressiblemiscibledisplacementinporousmediawhichincludesmoleculardiffusionandmechanicaldispersioninone-dimensionalspace.Aclassofvertices-edges-elementsinterpolationoperatorinkisintroduced.Withthehelpofink(notellipticprojection),theoptimalerrorestimateinL∞(J;L2(Ω))normofFEMisproved.

  • 标签: Molecular diffusion and mechanical dispersion SINGLE-PHASE
  • 简介:Inthispaper,theLp-convergenceofGrünwaldinterpolationGn(f,x)basedonthezerosofJacobipolynomialsJ(α,β)n(x)(-1<α,β<1)isconsidered.Lp-convergence(00)ofGn(f,x)isobtainedfor-1<α,β≤0.Therefore,theresultsof[1]and[3-5]areimproved.

  • 标签: INTERPOLATION JACOBI ON L_p inequality notes
  • 简介:WeconsiderdiffusivelimitoftheBoltzmannequationinaperiodicbox.WeestablishL~6estimateforthehydrodynamicpartPfofparticledistributionfunction,whichleadstouniformboundsglobalintime.

  • 标签: L~6 ESTIMATE BOLTZMANN EQUATION diffusive LIMIT