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本原代换的非周期不动点的Hausdorff维数函数
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作者 贾保国 《数学年刊(A辑)》 CSCD 北大核心 2000年第6期739-744,共6页
设 A={0, 1,…, N-1},ξ是 A上的一个本原代换, u是ξ的非周期不动点.记 X(ξ)=Orb(u)
关键词 本原代换 Hausdorff维数函数 Morse序列 FIBONACCI序列 非周期不动点
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与FMRA相联系的Parseval框架多小波的刻画 被引量:2
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作者 吴国昌 许素梅 杨晓慧 《河南师范大学学报(自然科学版)》 CAS CSCD 北大核心 2009年第6期25-27,共3页
通过Parseval框架多小波的维数函数,与一个框架多尺度分析相联系的Parseval框架多小波的充要条件被给出,从而来自于一个多尺度分析的Parseval框架多小波的刻画问题被彻底地解决.
关键词 Parseval 框架多小波 维数函数 半正交小波 框架多尺度分析
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基于多重分形理论的近海污染物空间分布特性研究 被引量:2
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作者 牛志广 陆仁强 何晓云 《海洋环境科学》 CAS CSCD 北大核心 2010年第1期99-103,共5页
针对我国近海污染物空间分布特征难于辩析的问题,通过对多重分形理论的研究,提出了一种新的近海污染物空间分布特征的分析方法。以天津市近岸海域20个水环境监测点为例,随机选择两个不同水期的COD监测数据进行分析,采用多重分形矩方法计... 针对我国近海污染物空间分布特征难于辩析的问题,通过对多重分形理论的研究,提出了一种新的近海污染物空间分布特征的分析方法。以天津市近岸海域20个水环境监测点为例,随机选择两个不同水期的COD监测数据进行分析,采用多重分形矩方法计算COD空间分布的多重分形维数谱函数f(α)。计算结果显示其α(q)-f(α)曲线均为连续不对称的上凸曲线,表明近海污染物在空间上的分布并不是简单的正态或对数正态分布,而是连续多重分形分布,近海污染物高浓度部分的奇异性较低浓度部分大,平水期的奇异性较丰水期大。应用表明,该分析结果与天津市近岸海域实际情况相一致,这些成果的取得为辩析近海污染物的空间分布特征,并进一步采用基于多重分形理论的算法模型计算近海水环境容量提供了理论依据。 展开更多
关键词 近海 污染物 多重分形 函数
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框架小波的可扩展性(英文)
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作者 王丽娟 李万社 江南 《纺织高校基础科学学报》 CAS 2008年第3期289-294,共6页
规范紧框架小波的可扩展性是超小波理论的一个重要方面.阐述了规范紧框架小波的维数函数的定义和相关性质.作为维数函数的应用,更进一步地研究了框架小波的可扩展性,得到了一个规范紧框架小波可扩展成任何长度超小的充分条件.另外,给出... 规范紧框架小波的可扩展性是超小波理论的一个重要方面.阐述了规范紧框架小波的维数函数的定义和相关性质.作为维数函数的应用,更进一步地研究了框架小波的可扩展性,得到了一个规范紧框架小波可扩展成任何长度超小的充分条件.另外,给出一个例子和两个推论. 展开更多
关键词 规范紧框架小波 维数函数 超小波
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A Class of Fractal Functions and Their Dimension Estimates 被引量:4
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作者 王宏勇 杨守志 《Chinese Quarterly Journal of Mathematics》 CSCD 2000年第4期84-90,共7页
本文作者首先借助于b进制分数及无穷级数构造了一类分形函数,然后研究了这些函数图象的分形维数及其Hoelder性质,得到了一些维数结果。
关键词 b-adic fraction fractal function fractal dimension Holder continuity
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关于Hausdorff测度的一个不等式
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作者 樊庆菊 商朋见 《北方交通大学学报》 CSCD 北大核心 2003年第3期43-45,共3页
在Besicovitch广义的Hausdorff测度定义下,推出了Hausdorff测度的一个不等式.
关键词 HAUSDORFF测度 上密度 下密度 维数函数
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我国沪铜期货价格的分形统计 被引量:5
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作者 苑莹 庄新田 《东北大学学报(自然科学版)》 EI CAS CSCD 北大核心 2008年第1期137-140,共4页
运用分形分布参数估计、函数盒维数以及多重分形分析等方法对我国沪铜期货价格时间序列进行了实证研究.结果表明,沪铜期货价格不服从正态分布,价格之间存在长记忆性,从而对有效市场假说提出了质疑.函数盒维数及多标度分析的结果揭示了... 运用分形分布参数估计、函数盒维数以及多重分形分析等方法对我国沪铜期货价格时间序列进行了实证研究.结果表明,沪铜期货价格不服从正态分布,价格之间存在长记忆性,从而对有效市场假说提出了质疑.函数盒维数及多标度分析的结果揭示了期货价格的聚类特征及标度变化,说明用单一分形模型来描述期货价格是不充分的,多重分形分析方法为更好地描述期货价格的变化规律提供了有力的工具. 展开更多
关键词 铜价格 上海期货市场 有效市场假说 分形 估计 函数
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Wigner Function of Density Operator for Negative Binomial Distribution 被引量:1
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作者 XU Xing-Lei LI Hong-Qi 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第6期1453-1456,共4页
By using the technique of integration within an ordered product (IWOP) of operator we derive Wigner function of density operator for negative binomial distribution of radiation field in the mixed state case, then we... By using the technique of integration within an ordered product (IWOP) of operator we derive Wigner function of density operator for negative binomial distribution of radiation field in the mixed state case, then we derive the Wigner function of squeezed number state, which yields negative binomial distribution by virtue of the entangled state representation and the entangled Wigner operator. 展开更多
关键词 IWOP Wigner function negative binomial distribution
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Wigner Function for Klein-Gordon Landau Problem
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作者 买吾兰江.热合曼 沙依甫加马力.达吾来提 李康 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第11期809-812,共4页
First we calculate the Wigner phase-space distribution function for the Klein-Gordan Landau problem ona commmutative space.Then we study the modifications introduced by the coordinate-coordinate noncommuting andmoment... First we calculate the Wigner phase-space distribution function for the Klein-Gordan Landau problem ona commmutative space.Then we study the modifications introduced by the coordinate-coordinate noncommuting andmomentum-momentum noncommuting, namely, by using a generalized Bopp’s shift method we construct the Wignerfunction for the Klein-Gordan Landau problem both on a noncommutative space (NCS) and a noncommutative phasespace (NCPS). 展开更多
关键词 Wigner function Klein-Gordan Landau problem noncommutative space noncommutative phasespace Bopp's shift
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Fractal Dimension of Graph of Weierstrass Function and Its Derivative of the Fractional Order
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作者 邓冠铁 《Chinese Quarterly Journal of Mathematics》 CSCD 1996年第3期50-54,共5页
In this paper,we obtain the fractal dimension of the graph of the Weierstrass function, its derivative of the fractional order and the relation between the dimension and the order of the fractional derivative.
关键词 fractals DIMENSION Weierstrass function fractional derivative order of fractional derivative
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A Lifting Line Theory for a Three-dimensional Hydrofoil 被引量:1
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作者 梁辉 宗智 《Journal of Marine Science and Application》 2011年第2期199-205,共7页
Prandtl’s lifting line theory was generalized to the lifting problem of a three-dimensional hydrofoil in the presence of a free surface. Similar to the classical lifting theory, the singularity distribution method wa... Prandtl’s lifting line theory was generalized to the lifting problem of a three-dimensional hydrofoil in the presence of a free surface. Similar to the classical lifting theory, the singularity distribution method was utilized to solve two-dimensional lifting problems for the hydrofoil beneath the free surface at the air-water interface, and a lifting line theory was developed to correct three-dimensional effects of the hydrofoil with a large aspect ratio. Differing from the classical lifting theory, the main focus was on finding the three-dimensional Green function of the free surface induced by the steady motion of a system of horseshoe vortices under the free surface. Finally, numerical examples were given to show the relationship between the lift coefficient and submergence Froude numbers for 2-D and 3-D hydrofoils. If the submergence Froude number is small free surface effect will be significant registered as the increase of lift coefficient. The validity of these approaches was examined in comparison with the results calculated by other methods. 展开更多
关键词 lifting line theory singularity distribution method 3-D hydrofoil free surface Green function
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New Exact Solutions to (2+1)-Dimensional Variable Coefficients Broer-Kaup Equations
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作者 ZHU Jia-Min 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第3X期393-396,共4页
In this paper, using the variable coefficient generalized projected Rieatti equation expansion method, we present explicit solutions of the (2+1)-dimensional variable coefficients Broer-Kaup (VCBK) equations. The... In this paper, using the variable coefficient generalized projected Rieatti equation expansion method, we present explicit solutions of the (2+1)-dimensional variable coefficients Broer-Kaup (VCBK) equations. These solutions include Weierstrass function solution, solitary wave solutions, soliton-like solutions and trigonometric function solutions. Among these solutions, some are found for the first time. Because of the three or four arbitrary functions, rich localized excitations can be found. 展开更多
关键词 variable coefficient generalized projected Ricatti equation method (2+l)-dimensional variable coefficients Broer-Kaup equations Weierstrass function solution solitary wave solution trigonometric function solution
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具有特殊伸缩矩阵的Parseval框架小波集的结构 被引量:3
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作者 黄永东 《数学学报(中文版)》 CSCD 北大核心 2016年第2期163-186,共24页
揭示具有特殊伸缩矩阵的Parseval框架小波集的丰富结构.借助于平移不变空间和维数函数,研究了具有特殊伸缩矩阵M的Parseval框架小波(M-PFW)、半正交M-PFW和MRA M-PFW的各种性质,探讨了M-PFW集合的各种子类,给出了这些子类的构造性算例.
关键词 特殊伸缩矩阵 Parseval框架小波 平移不变空间 维数函数
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A-Parseval框架小波的特征刻画
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作者 黄永东 孙娜 《数学学报(中文版)》 SCIE CSCD 北大核心 2011年第5期767-790,共24页
研究与伸缩矩阵A相关的Parseval框架小波(A-PFW)的特征刻画,其中伸缩矩阵A满足A^3=2I_3且A的每一列元素之和均为偶数.首先,讨论了与两个特殊伸缩矩阵B,C相关的Parseval框架小波(B-PFW,C-PFW)之间的关系,并得到C-PFW分别与两类特殊伸缩矩... 研究与伸缩矩阵A相关的Parseval框架小波(A-PFW)的特征刻画,其中伸缩矩阵A满足A^3=2I_3且A的每一列元素之和均为偶数.首先,讨论了与两个特殊伸缩矩阵B,C相关的Parseval框架小波(B-PFW,C-PFW)之间的关系,并得到C-PFW分别与两类特殊伸缩矩阵D,■相关的Parseval框架小波(D-PFW,■-PFW)之间的等价关系.其次,探讨了伪尺度函数和源于多分辨分析的A-PFW(MRA A-PFW)的特征刻画.最后,借助于维数函数,给出了A-PFW是MRA A-PFW的一个充要条件. 展开更多
关键词 Parseval框架小波 MRA 小波 维数函数
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On the Dimension for Multivariate Weak Spline Function Spaces
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作者 许志强 王仁宏 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2002年第1期7-12,共6页
In this paper, the dimension formulaes of multivariate weak spline are discussed. The dimension formulaes of non-degree multivariate weak spline on a vertex are presented. The dimension formulaes on triangulation are ... In this paper, the dimension formulaes of multivariate weak spline are discussed. The dimension formulaes of non-degree multivariate weak spline on a vertex are presented. The dimension formulaes on triangulation are also discussed. At last, the local supported bases of W31(I1Δ) are presented. 展开更多
关键词 SPLINE weak spline dimension.
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Blow Up of Solutions to Semilinear Wave Equations with Critical Exponent in High Dimensions 被引量:22
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作者 Yi ZHOU 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2007年第2期205-212,共8页
In this paper, the author considers equations with critical exponent in n ≥4 space tions on the initial data, it is proved that there small the initial data are. the Cauchy problem for semilinear wave dimensions. Und... In this paper, the author considers equations with critical exponent in n ≥4 space tions on the initial data, it is proved that there small the initial data are. the Cauchy problem for semilinear wave dimensions. Under some positivity condican be no global solutions no matter how 展开更多
关键词 Semilinear wave equation Critical exponent Cauchy problem Blow up
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Sound absorption performance of natural fibers and their composites 被引量:15
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作者 YANG WeiDong LI Yan 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第8期2278-2283,共6页
This research aimed to study the sound absorption properties of natural fibers and their reinforced composites.Sound absorption coefficients of three types of natural fibers,i.e.,ramie,flax and jute fibers and their c... This research aimed to study the sound absorption properties of natural fibers and their reinforced composites.Sound absorption coefficients of three types of natural fibers,i.e.,ramie,flax and jute fibers and their composites were measured by the two-microphone transfer function technique in the impedance tube.The results were compared with synthetic fibers and their composites.It was found that both natural fibers and their composites had superior capability of noise reduction.The multi-scale and hollow lumen structures of natural fibers contributed to the high sound absorption performance.Moreover,the sound absorption properties of these natural fibers were also calculated by the Delany-Bazley and Garai-Pompoli models.They showed good agreement with the experimental data.It was concluded that multi-functional composite materials can be made by natural fibers so that both the mechanical and acoustical functions can be achieved. 展开更多
关键词 natural fiber reinforced composites sound absorption impedance tube
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The Hausdorf dimension of certain sets in a class of α-Lroth expansions
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作者 CHEN HaiBo WEN ZhiXiong 《Science China Mathematics》 SCIE 2014年第2期303-313,共11页
In this paper,we consider sets of points with some restricts on the digits of theirα-Lroth expansions.More precisely,for any countable partitionα={An,n∈N}of the unit interval I,we completely determine the Hausdorf ... In this paper,we consider sets of points with some restricts on the digits of theirα-Lroth expansions.More precisely,for any countable partitionα={An,n∈N}of the unit interval I,we completely determine the Hausdorf dimensions of the sets F(α,φ)=x=[l1(x),l2(x),...]α∈I:ln(x)φ(n),n 1,whereφis an arbitrary positive function defined on N satisfyingφ(n)→∞as n→∞. 展开更多
关键词 Hausdorff dimension the a-Ltiroth expansion EXPANDING expansive exponent eventually de-creasing
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Three-dimensional aerodynamic optimization design of high-speed train nose based on GA-GRNN 被引量:24
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作者 YAO ShuanBao GUO DiLong YANG GuoWei 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第11期3118-3130,共13页
With the speed upgrade of the high-speed train,the aerodynamic drag becomes one of the key factors to restrain the train speed and energy saving.In order to reduce the aerodynamic drag of train head,a new parametric a... With the speed upgrade of the high-speed train,the aerodynamic drag becomes one of the key factors to restrain the train speed and energy saving.In order to reduce the aerodynamic drag of train head,a new parametric approach called local shape function(LSF) was adopted based on the free form surface deformation(FFD) method and a new efficient optimization method based on the response surface method(RSM) of GA-GRNN.The optimization results show that the parametric method can control the large deformation with a few design parameters,and can ensure the deformation zones smoothness and smooth transition of different deformation regions.With the same sample points for training,GA-GRNN performs better than GRNN to get the global optimal solution.As an example,the aerodynamic drag for a simplified shape with head + one carriage + tail train is reduced by 8.7%.The proposed optimization method is efficient for the engineering design of high-speed train. 展开更多
关键词 aerodynamic drag GA-GRNN PARAMETRIC high-speed trains
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The first eigenfunctions and eigenvalue of the p-Laplacian on Finsler manifolds 被引量:1
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作者 YIN SongTing HE Qun 《Science China Mathematics》 SCIE CSCD 2016年第9期1769-1794,共26页
This paper proves that the first eigenfunctions of the Finsler p-Lapalcian are C^(1,α). Using a gradient comparison theorem and one-dimensional model, we obtain the sharp lower bound of the first Neumann and closed e... This paper proves that the first eigenfunctions of the Finsler p-Lapalcian are C^(1,α). Using a gradient comparison theorem and one-dimensional model, we obtain the sharp lower bound of the first Neumann and closed eigenvalue of the p-Laplacian on a compact Finsler manifold with nonnegative weighted Ricci curvature,on which a lower bound of the first Dirichlet eigenvalue of the p-Laplacian is also obtained. 展开更多
关键词 the first eigenvalue p-Laplacian Ricci curvature S curvature
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