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Table of Content

    26 August 2018, Volume 38 Issue 4 Previous Issue   
    A Flowbox Theorem with Uniform Relative Bound
    Han Bo
    Acta mathematica scientia,Series A. 2018, 38 (4):  625-630. 
    Abstract ( 116 )   RICH HTML PDF (299KB) ( 114 )   Save
    In this paper, we give a flowbox theorem for the Lipschitz vector fields on a Banach spcace. We prove:if X is a Lipschitz vector field with a Lipschitz constant L, then there is a constant r0 associated to L only such that for any regular point x of X, there is a flowbox with size r0||X(x)||, and the Lipschitz constants of the respected lipeomorphism in the flowbox theorem has a uniform bound.
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    A Sharper Uncertainty Principle for L2(Rn) Space
    Qu Feifei, Deng Guantie
    Acta mathematica scientia,Series A. 2018, 38 (4):  631-640. 
    Abstract ( 99 )   RICH HTML PDF (271KB) ( 91 )   Save
    In this paper, we generalize some definitions of a signal about time and Fourier frequency to a function f(t) ∈ L2(Rn) and propose a form of uncertainty principle strictly stronger than Heisenberg inequality in L2(Rn). We also deduce the conditions that give rise to the equal relation of the uncertainty principle.
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    Complex Approximation Properties of the Baskakov-Kantorovich Operators in Compact Disks
    Li Wenxia, Qi Qiulan
    Acta mathematica scientia,Series A. 2018, 38 (4):  641-648. 
    Abstract ( 101 )   RICH HTML PDF (240KB) ( 71 )   Save
    In this paper, the approximation properties of the modified Baskakov-Kantorovich operators are studied according to the definition and properties in the complex space. We obtain the approximation order for the modified complex Baskakov-Kantorovich operators attached to entire functions or to analytic functions in compact disks.
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    Perturbation Analysis for Constrained Extremal Solution Problems in Reflexive Strictly Convex Banach Spaces
    Cao Jianbing
    Acta mathematica scientia,Series A. 2018, 38 (4):  649-657. 
    Abstract ( 121 )   RICH HTML PDF (361KB) ( 58 )   Save
    In this paper, with the help of recent perturbation results of the Moore-Penrose metric generalized inverse, also based on an equivalent formation of the constrained extremal solution problems and the perturbation result for general extremal solution problems, we present some results on the perturbation analysis for extremal solution problems with equality constraints in reflexive strictly convex Banach spaces. As a consequence, some particular cases and applications will be also presented.
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    Prolongation Structures of Generalized Coupled Equation
    Bai Xirui
    Acta mathematica scientia,Series A. 2018, 38 (4):  658-670. 
    Abstract ( 113 )   RICH HTML PDF (326KB) ( 58 )   Save
    In this paper, we adopt the theory of continuation structure and properties of simple or semi-simple Lie algebra and studied the prolongation structure for two dual systems. Furthermore, the Lax pair of these equations are obtained by the method of Lie representation theory. Considering the CH type equation, based on analysing its determined equations, we select the functions F that ord(F) ≤ 2. However, there merely exists one order situation through calculation and analysis.
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    q-Equicontinuous Points and q-Sensitive Points
    Zhong Yuehua, Wang Huoyun
    Acta mathematica scientia,Series A. 2018, 38 (4):  671-678. 
    Abstract ( 57 )   RICH HTML PDF (354KB) ( 41 )   Save
    In this paper, we introduced the notions of q-equicontinuous points and q-sensitive points. We showed that a point xX is mean equicontinuous point of a dynamical system (X, T) if and only if it is a q-equicontinuous point of (X, T) for any q belongs to[0,1). And a point xX is mean sensitive point of a dynamical system (X, T) if and only if it is a q-sensitive (X, T) point for some q belongs to (0, 1].
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    The Inverse Problem for the Supersonic Plane Flow Past a Curved Wedge
    Wang Li
    Acta mathematica scientia,Series A. 2018, 38 (4):  679-686. 
    Abstract ( 59 )   RICH HTML PDF (270KB) ( 71 )   Save
    The inverse problem for the supersonic plane flow described by TSD equation past a curved wedge is considered. For a uniform supersonic oncoming flow, under the hypothesis that the position of the shock is given, we will globally determine the curved wedge. This kind of problem plays an important role in the aviation industry. Under suitable assumptions, with the help of Riemann invariants and Lax transform, by solving a generalized Cauchy problem, the global existence and uniqueness for the above mentioned problem is established.
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    On the Existence of Positive Solutions for Generalized Quasilinear Schrödinger Equations
    Xie Chaodong, Chen Zhihui
    Acta mathematica scientia,Series A. 2018, 38 (4):  687-696. 
    Abstract ( 102 )   RICH HTML PDF (310KB) ( 82 )   Save
    In this paper, we prove the existence of positive solutions for generalized quasilinear Schrödinger equations. By detailed analysis of g(u) in -div(g2(u)▽u), we have better results.
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    An Existence Result for Impulsive Boundary Value Problem for Fractional Differential Equations with Multiple Base Points
    Wang Huiwen, Zeng Hongjuan, Li Fang
    Acta mathematica scientia,Series A. 2018, 38 (4):  697-715. 
    Abstract ( 68 )   RICH HTML PDF (374KB) ( 66 )   Save
    In this paper, we study the existence of solutions for impulsive boundary value problem for nonlinear multiple base points differential equations of fractional order α ∈ (1, 2). By using some well-known fixed point theorem, we obtain an existence result on solution under the weak assumption. Three examples are given to illustrate the existence theorems.
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    Boundedness of the Intrinsic Square Function on Variable Exponent Herz and Herz-Hardy Spaces
    Wang Liwei, Shu Lisheng
    Acta mathematica scientia,Series A. 2018, 38 (4):  716-727. 
    Abstract ( 90 )   RICH HTML PDF (337KB) ( 75 )   Save
    In this paper, we show that the intrinsic square function Sβ is bounded on the variable exponent Herz spaces Kp(·)α(·), q(Rn) and Herz-Hardy spaces HKp(·)α(·), q(Rn), where α(·) and p(·) are variable. In particular, when α(·) ≡ α is constant, the corresponding main results are also new.
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    Oscillation of Generalized Emden-Fowler Differential Equations with Nonlinear Neutral Term
    Zhang Xiaojian
    Acta mathematica scientia,Series A. 2018, 38 (4):  728-739. 
    Abstract ( 70 )   RICH HTML PDF (374KB) ( 61 )   Save
    We study the oscillatory behavior of a certain class of second-order nonlinear variable delay generalized Emden-Fowler functional differential equations with a nonlinear neutral term of the form
    {a(t)|[x(t)+p(t)xα(τ(t))]'|β-1[x(t)+p(t)xα(τ(t))]'}'+q(t)f(|x(δ(t))|γ-1x(δ(t)))=0(tt0). By using the generalized Riccati transformation and Bernoulli's inequality and Yang's inequality, we establish some new oscillation criteria for the equations under the cases when
    t0+∞ a-1/β(t)dt=+∞ and ∫t0+∞ a-1/β(t)dt < +∞,
    the results obtained extend and improve some related results reported in the literature. Examples are provided to illustrate assumptions in our theorems are less restrictive.
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    Oscillation Analysis of Analytical Solutions for a Kind of Nonlinear Neutral Delay Differential Equations with Several Delays
    Wang Huiling, Gao Jianfang
    Acta mathematica scientia,Series A. 2018, 38 (4):  740-749. 
    Abstract ( 88 )   RICH HTML PDF (304KB) ( 83 )   Save
    This paper is concerned with oscillation of a kind of nonlinear neutral delay differential equations with constant coefficients. The sufficient conditions for oscillation in the case of 0 < p < 1 and the sufficient and necessary conditions for oscillation in the case of p ≥ 1 are obtained, respectively. To compare with other existing results, we give two experiments to verify our results.
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    Blow-Up Analysis for a Nonlocal Reaction-Diffusion Equation with Variant Diffusion Coefficient
    Zhao Yuanzhang, Ma Xiangru
    Acta mathematica scientia,Series A. 2018, 38 (4):  750-769. 
    Abstract ( 50 )   RICH HTML PDF (412KB) ( 61 )   Save
    In this paper, blow-up phenomena for the Dirichlet initial boundary value problem of a reaction-diffusion equation with variant diffusion coefficient is considered. By virtue of the auxiliary function method and the modified differential inequality, we established appropriate conditions on variant diffusion coefficient and nonlinearities to guarantee existence of global solution or blow-up solution at finite time. Moreover, lower bounds for the blow-up time of the solution are derived in all dimensional spaces (N ≥ 1). In the meantime, several examples are presented to illustrate applications of our results.
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    Interval Bifurcation for the p-Laplacian Equation and Its Applications
    Shen Wenguo
    Acta mathematica scientia,Series A. 2018, 38 (4):  770-778. 
    Abstract ( 58 )   RICH HTML PDF (345KB) ( 58 )   Save

    In this paper, we establish a unilateral global interval bifurcation result for the p-Laplacian equation. Furthermore, we shall prove the existence of the principal half-eigenvalues for the half-linear p-Laplacian equation. Moreover, we also investigate the existence of radial nodal solutions for the problems.
    ,
    where 1< p < +∞, ψp(s)=|s|p-2s, a(r) ∈ C[0, 1], a(r) ≥ 0,a(r)?0 on any subinterval of[0, 1]; λ is a parameter, u+=max{u, 0}, u-=-min{u,0}, α, βC[0, 1] are radially symmetric; fC(R, R), sf(s) > 0 for s∈R+, and f0 ∈[0, ∞) and f ∈ (0, ∞) or f0 ∈ (0, ∞] and f=0 or f0=0 and f=∞, where f0= f(s)/s, f=f(s)/s. We use unilateral global bifurcation techniques and the approximation of connected components to prove our main results.

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    Carleman Estimate for a 2×2 Strongly Coupled Partial Differential System with Nonsingular Coefficient Matrix of Principal Parts and Application to an Inverse Source Problem
    Wu Bin, Gao Ying, Yan Lin, Yu Jun
    Acta mathematica scientia,Series A. 2018, 38 (4):  779-799. 
    Abstract ( 77 )   RICH HTML PDF (409KB) ( 226 )   Save
    We study a Carleman estimate for a 2×2 strongly coupled partial differential system with nonsingular coefficient matrix of principal parts. Different from the method to prove Carleman estimate for a strongly coupled hyperbolic system as in[7] and[15], we first establish a pointwise Carleman estimate by considering two equations in the governing system as a whole rather than by using diagonalization of the system. Furthermore, we prove a global Carleman estimate for this kind of strongly coupled differential system. Finally, as an application, we establish a Hölder stability for an inverse problem of determining two source functions by the boundary observation data.
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    Green's Function Method for the First Boundary Value Problem of Poisson Equation in the Quadric Surface Region
    Xiang Pei, Fu Jingli
    Acta mathematica scientia,Series A. 2018, 38 (4):  800-809. 
    Abstract ( 84 )   RICH HTML PDF (383KB) ( 63 )   Save
    Green's function method is an important way to solve the modern physical problems. The wave equation, the diffusion equation, the Helmholtz equation, the Poisson equation, which is one of the important equations to describe the steady field, and many problems in modern engineering can be solved by using Green's function method. For the first boundary value problem of Poisson equation, most of the research only gives the Green's function solution to the areas with ellipsoidal surface or spherical surface and so on, but there is little discussion on other types of areas. Based on the quadratic surface imaging formula, the first boundary value problem of the Poisson equation in the areas with quadratic surfaces such as ellipsoid, hyperboloid, paraboloid and sphere is studied uniformly in this text by using electric image method. The purpose is to give the Green's function.
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    One-Pulse Travelling Front Solutions of a sine-Gordon Equation with Slowly Varying Parameters
    Liao Shupeng, Shen Jianhe
    Acta mathematica scientia,Series A. 2018, 38 (4):  810-822. 
    Abstract ( 54 )   RICH HTML PDF (591KB) ( 62 )   Save
    By combining Fenichel's geometric singular perturbation theory and Melnikov function method, this paper studies the existence of 1-pulse travelling front solutions of a sineGordon equation with slowly varying parameters. Firstly, we get the layer system and the reduced system respectively as well as their global dynamics via the technique of fast-slow separation, and then, we introduce the Melnikov function to determine the transversal intersections between the stable and unstable manifolds of the slow manifold, where we define the so-called Take-off and Touch-down curves. By controlling the Take-off and Touch-down curves to respectively intersect with the stable and unstable manifolds of the saddle points on the slow manifolds transversally, we get the singular heteroclinic orbits with transversality. Correspondingly we get the existence of heteroclinic orbits of the full singularly perturbed system by perturbing such singular heteroclinic orbits. Finally, we consider an example to verify the correctness of the obtained theoretical results.
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    A Filtering Algorithm for Removing Cauchy Noise in Images
    Wang Xiaoyan, Ding Yiming
    Acta mathematica scientia,Series A. 2018, 38 (4):  823-832. 
    Abstract ( 86 )   RICH HTML PDF (2231KB) ( 76 )   Save
    Digital images may be disturbed by different noises during acquisition and transfer processes. Treatment methods are varied with the characteristics of noises. It is interesting to develop algorithms to recover the images from strong noises, because the traditional filtering algorithms do not work well in strong noises. A new filtering algorithm combined median filtering with local area pixel clustering is proposed to filter strong Cauchy noises from digital images. Based on the processing of three images with Cauchy noise, it is demonstrated that the algorithm can obtain more details of images than the median filtering. In comparison with other methods, our filtering algorithm is an effective strong noise removal filtering algorithm because it protects image details and the edges significantly.
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