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    03 August 1999, Volume 19 Issue 3 Previous Issue    Next Issue
    Articles

    Solvability and Hypoellipticity for  Operate  Lm&mu|on the Heisenberg Group Hn

    Ma Yulan Luo Xuebo
    Acta mathematica scientia,Series A. 1999, 19 (3):  241-246. 
    Abstract ( 781 )   RICH HTML PDF (341KB) ( 760 )   Save

    In this paper ,explicit fundament solution um for partial differential oprator Lmμ on the Heisenberg group Hn is given .By using this um,the solvability and teh hypoellipticity for operator Lmμ  are studied.

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    Existence and Uniqueness of Solutions for Boundary Value Problems of Higher Order Ordinary Differential Equations
    Hong Shihuang Hu Shigeng
    Acta mathematica scientia,Series A. 1999, 19 (3):  247-255. 
    Abstract ( 762 )   RICH HTML PDF (362KB) ( 896 )   Save

    In this paper,we consider the boundary value problems of higher order ordinary differentinal  equations.By using the monotone iterative technique, some existence and uniqueness theorms for solutions are obtained.

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    The Decay Rate of a One Dimensional Linesr Themoelastic System with Boundary Stabilizer
    Zhou Rong Guo Baozhu
    Acta mathematica scientia,Series A. 1999, 19 (3):  256-265. 
    Abstract ( 1041 )   RICH HTML PDF (365KB) ( 719 )   Save

    In this paper,we give an asymptotic estimation of the eigenfrequencies of a one dimensional thenoelastic system with one end stress damping.It is shown that this kind of boundry stress feedback can improve arbitrarily thr decay rate of teh higher eigenfrequencies.The Legendre spectral method is used to compute the eigenvalues of teh damped operator.Numerical results confirms teh theoretical estimations.

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    A |note on end-regularity of teh join of two trees
    Li Weimin
    Acta mathematica scientia,Series A. 1999, 19 (3):  266-269. 
    Abstract ( 719 )   RICH HTML PDF (337KB) ( 667 )   Save

    In this paper ,the join of two trees with a regular monoid is explicitly described .

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    The Herz Spaces on Space of Homogeneous Type and Their Applications
    Liu Zongguang Zen Yuesheng
    Acta mathematica scientia,Series A. 1999, 19 (3):  270-277. 
    Abstract ( 794 )   RICH HTML PDF (327KB) ( 875 )   Save

    In this paper,we define the Herz spaces and weak Herz spaces on spaces of homogeneous type and study teh properties of some sublinear operators on these spaces .

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    Fem with |teh Method of Characteristics for Compressible Flow of Contamination From Nuclear Waste in Porous Media
    Cheng Aijie Wang Gaohong
    Acta mathematica scientia,Series A. 1999, 19 (3):  278-285. 
    Abstract ( 858 )   RICH HTML PDF (384KB) ( 899 )   Save

    We wii study teh finite element method for compressible flow of contamination from nuclear in porous media,in which both of molecular diffusion and dispersion are considered.The mathematical model is a coupled quasilinear syetem of parabolic equations about pressure,temperature,brine and radionuclide.Starting from  teh primitive model ,finite element scheme based on teh method of characterristics is estabilishe and analysed.Some new estimates about elliptic projection are given,a modified tachnique is proposed to establish teh evolution inequlity for pressure error,the optimal error estimate in L∞ (J;H1(Ω))is proved.

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    Some New Applications of Homogeneous Balance Method
    Fan Engui Zhang Hongqing
    Acta mathematica scientia,Series A. 1999, 19 (3):  286-292. 
    Abstract ( 771 )   RICH HTML PDF (338KB) ( 1485 )   Save

    The homogeneous balance method is very effective to seek for solitary wave solution of nonliear evolution equations. in this paper we will give three kinds of important applictions of homogenceous balance method;1)to find new exact solutions for nonlinear evolution equaton;2)to seek for Backlund transformation and Lax  parirs of nonlinear evolution ;3)to give symmetry reduction and similarity solution of nonlinear evolution equation .

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    Generalized Gaussian Integral |Method for Calculations of Scaling Function Transform of Wavelets |and Its Application
    Zhou Jihe Wang Jizeng
    Acta mathematica scientia,Series A. 1999, 19 (3):  293-300. 
    Abstract ( 1043 )   RICH HTML PDF (465KB) ( 1389 )   Save

    in this paper,a generalized Gaussian integral method is established to take calculation of intergral for decomposion  coefficients of the scaling function transform in the Daubechies wavelet theory.By using teh resolution level increases.After taht,an explicit formula of reconstruction of functions based on teh scaling function transform is deduced out.and some expressions are displayed to functional,differential and integral operations of functions.it is found that this method is powerful to solve for soulutions of strong nonlinear problems.finally,an example of a two-point boundary value problem with strong nonliearity is given to show the efficiency of teh method.

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    The Singular Perturbed Nonlocal Boundary Value Problems for Higher Order of Nonilinear Elliptic Equations
    Mo Jiaqi
    Acta mathematica scientia,Series A. 1999, 19 (3):  301-306. 
    Abstract ( 823 )   RICH HTML PDF (320KB) ( 803 )   Save

    in this paper a class of singular perturbation of nonlocal boundary value problems for elliptic partial differentail equations of hingher order is considered by using teh differential inequalities,the uniformly valid asymptotic expansion of solution is obtained .

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    Diophantine Approximation,Gevrey Hypoellipticity and Almost Periodic Motion on the Torus T2
    Chen Wwenyi Tian Yan
    Acta mathematica scientia,Series A. 1999, 19 (3):  307-311. 
    Abstract ( 924 )   RICH HTML PDF (323KB) ( 760 )   Save

    IN THIS paper,we consider a class of irrational rumber which can be  approximated by rational number at most exponental order,Applications are given in partial differential equation and dynamical systems.

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    High-Order Runge-Kutta Methods With Two Parameters
    Ruan Baogeng
    Acta mathematica scientia,Series A. 1999, 19 (3):  312-317. 
    Abstract ( 741 )   RICH HTML PDF (341KB) ( 680 )   Save

    a class of runge-kutta methods charaterized only by two parameters RKs(μ,δ)  is given  so taht all s-stage runge-kutta methods with distinct abscissas in the interval [0,1],if consisistent of order at less 2s-1 ,are recovered as special cases .for these methods both a-stability or algebraic stability are all equivalent to the condition μ≧,this criteria is an improvement of a famous result by burrage ([3],theorem 4.6.11).based on the methods of this class arbitrarily high order exponentially fitted methods are offered which are algebraically stable and therefore suitable for integration with a large stepsize for fast decaying components of stiff systems.

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    On Square-Rooting Matrices of A Jordan Block
    Zhu Degao
    Acta mathematica scientia,Series A. 1999, 19 (3):  318-321. 
    Abstract ( 979 )   RICH HTML PDF (280KB) ( 883 )   Save

    in this paper ,we give that a  jordan block Jm(λ)   has square -rooting matrices if and only if m=11 or λ≠0,Jm(λ)  has exactly two square-rooting matrices::±A,where a1 = c , a2 = 1/2c , a3 = -1/8c3 , ,

     ak = -(a2ak-1+a3ak-2++ak-2a3+ak-1a2)/2a1 , (k=3,4,,m), c2 = λ.

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    Coexistence of Two Species |in Competitive |Systems
    Li Fuyi Shen Peilong Feng Jinfeng
    Acta mathematica scientia,Series A. 1999, 19 (3):  322-325. 
    Abstract ( 748 )   RICH HTML PDF (311KB) ( 968 )   Save

    in this paper we study the coexistence of two species in competitive  systems by using the theory of cone and order in banach spaces,and obtain that two species in competitive systems can attain unique a coexistence under certain conditions.

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    Wuwen-tsun-Differential Charateristic Algorithm of Symmetry Vectors of Partial Differential Equations
    Chao Lu
    Acta mathematica scientia,Series A. 1999, 19 (3):  326-332. 
    Abstract ( 752 )   RICH HTML PDF (369KB) ( 638 )   Save

     In this paper,The Wu-differential characteristic set algorithm for computations symmetries of partial differential equations(PDEs) and the united theoretic framework for determination of classical and nonclassical symmetries of PDEs are put forwarded.The algorithm always yield all Determining equatins  (D.Es) of symmetry of the considering   PDEs and makes the“superlargescale”D.Es equivalently  reduce to“smallerscale” set of differential  equaitons and therefore significantly  decrease the computational efforts of  solving D.Es.Also a principle of Mechanical symmetry computing and testing of PDEs'symmetry is given.As an application of our algorithm,completely nonclassical symmetries of Burgers equation are calculated.

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    A Problem of Lower Bounds for the Modulus of Analytic Functions
    Wang Guang
    Acta mathematica scientia,Series A. 1999, 19 (3):  333-337. 
    Abstract ( 1162 )   RICH HTML PDF (295KB) ( 877 )   Save

     In this paper,we give a lower bound for the modulus of analytic functions which have zeros is |z|<R; the corollary extends Thm.1 of [4] in such a waythat one can easIly deduce the results of[5] about division in weighted algebras of analytic functions on the unit disc.

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    The Probability Character of Statistically Self-Similar Sets And Measures
    Hu Dihe
    Acta mathematica scientia,Series A. 1999, 19 (3):  338-346. 
    Abstract ( 830 )   RICH HTML PDF (357KB) ( 801 )   Save

    In this paper,we have proved that the statistically self-similar set is generated by a collection of random contraction operators{fσ,σ∈D},where fσ isa random elements from probability space(Ω,,P) to con(E),and con(E) denotes all contraction operators from complete separable metric spaceEtoE.

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    A new exploration of the inverse operator solution for a kind of strong nonliear partial differential equations with initial-boundary value problems
    Wu Baoting Sun Yanping
    Acta mathematica scientia,Series A. 1999, 19 (3):  347-355. 
    Abstract ( 709 )   RICH HTML PDF (376KB) ( 893 )   Save

     By means of the Inverse Operator Method, the approximate analytic solution for the mathematical model of the packed bed catalytic reactor (i.e.akind of strong nonliner partial differential equations  with initial-boundary value problems) are studied.A new technique,which replaces‘the arithmetic mean of the partial solutions’by ‘the geometry mean of the partial solutions’, is put forward. The technique leds that the appoximate analytic solutions are given reasonably.

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    Deficient functions of Random power Series
    Sun Daochun
    Acta mathematica scientia,Series A. 1999, 19 (3):  356-360. 
    Abstract ( 752 )   RICH HTML PDF (302KB) ( 809 )   Save

     The paper studies the random power series of general enough,and proves that the random power series of finite order do not have almost surely deficient function.

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