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461 个结果
  • 简介:以未来火星探测任务为背景,简要分析了通过气动刹车到达目标轨道方案的优缺点。基于给定的火星大气修正指数模型,建立了气动刹车的动力学模型。针对飞行器自身和轨道限制,设置必要的约束条件,利用高斯求解出气动刹车方案中每个周期所需的维持近火点高度的脉冲速度增量,实现了通过气动刹车的方式到达指定轨道的目标。结果表明,利用高斯优化计算得到的气动刹车方案可以满足要求,可为气动刹车相关的后续研究提供新的思路。

  • 标签: 火星探测 高斯伪谱法 轨道仿真 气动刹车
  • 简介:TheauthorobtainsaWeierstrassrepresentationforsurfaceswithprescribednormalGaussmapandGausscurvatureinH3.AdifferentialequationaboutthehyperbolicGaussmapisalsoobtained,whichcharacterizestherelationamongthehyperbolicGaussmap,thenormalGaussmapandGausscurvature.TheauthordiscussestheharmonicityofthenormalGaussmapandthehyperbolicGaussmapfromsurfacewithconstantGausscurvatureinH3toS2withcertainalteredconformalmetric.Finally,theauthorconsidersthesurfacewhosenormalGaussmapisconformalandderivesacompletelynonlineardifferentialequationofsecondorderwhichgraphmustsatisfy.

  • 标签: 双曲空间 高斯映射 调和映射 WEIERSTRASS表示 曲率
  • 简介:StabilizedorChebyshevexplicitmethodshavebeenwidelyusedinthepasttosolvestiffordinarydifferentialequations.MakinguseofspecialpropertiesofChebyshev-likepolynomials,thesemethodshavefavorablestabilitypropertiescomparedtostandardexplicitmethodswhileremainingexplicit.Anewclassofsuchmethods,calledROCK,introducedin[Numer.Math.,90,1-18,2001]hasrecentlybeenextendedtostiffstochasticdifferentialequationsunderthenameS-ROCK[C.R.Acad.Sci.Paris,345(10),2007andCommun.Math.Sci,6(4),2008].InthispaperwediscusstheextensionoftheS-ROCKmethodstosystemswithdiscretenoiseandproposeanewclassofmethodsforsuchproblems,theT-ROCKmethods.Onemotivationforsuchmethodsisthesimulationofmulti-scaleorstiffchemicalkineticsystemsandsuchsystemsarethefocusofthispaper,butournewmethodscouldpotentiallybeinterestingforotherstiffsystemswithdiscretenoise.TwoversionsoftheT-ROCKmethodsarediscussedandtheirstabilitybehaviorisanalyzedonatestproblem.ComparedtotheT-leapingmethod,asignificantspeed-upcanbeachievedforsomestiffkineticsystems.Thebehavioroftheproposedmethodsaretestedonseveralnumericalexperiments.

  • 标签: 切比雪夫 离散噪声 刚性常微分方程 动力学系统 随机微分方程 ACAD
  • 简介:Weraiseandpartlyanswerthequestion:whetherthereexistsaMarkovsystemwithrespecttowhichthezerosoftheChebyshevpolynomialsaredense,butthemaximumlengthofazerofreeintervalofthenthChebyshevpolynomialdoesnottendstozero.Wealsodrawtheconclu-tionthataMarkovsystem,underanadditionalassumption,isdenseifandonlyifthemaxi-mumlengthofazerofreeintervalofthenthassociatedChebyshevpolynomialtendstozero.

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  • 简介:LetthelinearsystemAx=bwherethecoefficientmatrixA=(aij)∈Rm,nisanL-ma-trix(thatis,aij>0(?)iandaij≤0(?)i≠j),A=I-L-U,Iistheidentitymatrix,-Land-Uare,respectively,strictlylowerandstrictlyuppertriangularpartsofA.In[1]theauthorsconsideredtwopreconditionedlinearsystems?x=(?)and?x=(?)

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  • 简介:<正>InthispaperwestudysurfacesinS~4andtheirtwistorGaussmaps.SomenecessaryandsufficientconditionsthatthetwistorGaussmapisharmonicaregiven.Wefindmanyexamplesofnonisotropicharmonicmapsfromasurfaceto(?)P~3.

  • 标签: Twistor GAUSS MAP HARMONIC MAP ISOTROPY
  • 简介:Inthispaper,ageneralalgorithmforthecomputationoftheFouriercoefficientsof2π-periodic(continuous)functionsisdevelopedbasedonDirichletcharacters,GausssumsandthegeneralizedM¨obiustransform.ItpermitsthedirectextractionoftheFouriercosineandsinecoefficients.Threespecialcasesofouralgorithmarepresented.AVLSIarchitectureispresentedandtheerrorestimatesaregiven.

  • 标签: 算术傅立叶变换 高斯和 人物 傅里叶系数 狄利克雷 直接提取
  • 简介:Inthispaper,weestablishanewtypeofalternationtheoryformoregeneralrestrictedrangesChebyshevapproximationwithequalities.Theuniquenessandstronguniquenesstheoremsaregiven.Applyingtheresults,weobtainthealternationtheoremanduniquenesstheoremforbestcoposiliveapproximation.

  • 标签: Chebyshev APPROXIMATION generaized Haar SUBSPACE RESTRICTED
  • 简介:本文引进带权的Chcbyshev逼近并给出它的应用。

  • 标签: 逼近 引进 应用
  • 简介:提出了用智能化极仪(JP-303型),在HC1O4-H3PO4-抗坏血酸体系中测定大量铟中锌的方法,锌浓度范围在0~300μg/mL时与锌的峰电流呈正比,锌标准工作曲线线性相关系数大于0.9998;所拟方法快速简便,不需分离铟便可直接测定0.00X%~XX%含量范围内的锌,样品加标回收率大于92%,样品多次(n=5)分析精密度满意,RSD<6%,解决了大量铟干扰锌测定的难题,效果良好.

  • 标签: 极谱测定
  • 简介:AnasynchronousparallelmultisplittingnonlinearGauss-SeideliterativemethodisestablishedfortheparticularlystructuredsystemofnonlinearequationsAφ(x)+Bφ(x)=bwithA,B∈(R^n)φ,φtR^n→R^nbeingdiagonalmappingsandb∈R^n,andtheglobalconvergenceofitisproved.

  • 标签: GAUSS-SEIDEL迭代法 异步平行 非线性方程 构建系统
  • 简介:ONEXCHANGEALGORITHMFORNONLINEARBESTCHEBYSHEVAPPROXIMATIONWITH LGHCONDITIONXiongGuijing(熊规景);WeiDan(韦旦)(Inst.ofMath.Sci.,Chin....

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  • 简介:性质awc1被许多作者使用由弱Chebyshevsubspaces的元素有关近似获得结果。在这份报纸,作者在细节学习这个性质,由收集有关它并且由发现新的散布结果。

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  • 简介:在这份报纸,我们考虑随机的线性补充问题(SLCP)的一个班与有限地许多元素。可行semismooth抑制了高斯牛顿算法因为SLCP被建议。建议算法的全球、局部地二次的集中在合适的条件下面被获得。一些数字结果在这份报纸被报导,它证实建议算法的好理论性质。

  • 标签: Gauss-Newton法 半光滑 求解 线性互补问题 局部二次收敛 算法理论