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Sharp Threshold of Global Existence for a Nonlocal Nonlinear Schr?dinger System in R3
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作者 Zaihui GAN Xin JIANG Jing LI 《数学年刊:B辑英文版》 SCIE CSCD 2019年第1期131-160,共30页
In this paper,the authors investigate the sharp threshold of a three-dimensional nonlocal nonlinear Schr?dinger system.It is a coupled system which provides the mathe- matical modeling of the spontaneous generation of... In this paper,the authors investigate the sharp threshold of a three-dimensional nonlocal nonlinear Schr?dinger system.It is a coupled system which provides the mathe- matical modeling of the spontaneous generation of a magnetic field in a cold plasma under the subsonic limit.The main difficulty of the proof lies in exploring the inner structure of the system due to the fact that the nonlocal effect may bring some hinderance for establishing the conservation quantities of the mass and of the energy,constructing the corresponding variational structure,and deriving the key estimates to gain the expected result.To overcome this,the authors must establish local well-posedness theory,and set up suitable variational structure depending crucially on the inner structure of the system under study,which leads to define proper functionals and a constrained variational problem.By building up two invariant manifolds and then making a priori estimates for these nonlocal terms,the authors figure out a sharp threshold of global existence for the system under consideration. 展开更多
关键词 NONLOCAL NONLINEAR Schr?dinger SYSTEM SHARP threshold BLOW-UP Global existence
Instability of Epitaxially Strained Thin Films Based on Nonlocal Elasticity
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作者 周旺民 李望君 《中国物理快报:英文版》 SCIE CAS CSCD 2019年第1期44-47,共4页
We perform a linear analysis of the elastic fields and stability of epitaxially strained thin films based on nonlocal elasticity.We derive expressions of perturbed stresses to the first order of perturbation amplitude... We perform a linear analysis of the elastic fields and stability of epitaxially strained thin films based on nonlocal elasticity.We derive expressions of perturbed stresses to the first order of perturbation amplitude,which show that the stresses are directly proportional to the lattice mismatch and the perturbation amplitude,and decrease with an increase in the perturbation wavelength.The critical perturbation wavelength distinguishes whether the fiat film for the perturbation is stable,which is inversely proportional to the square of the mismatch and decreases with the thickness of the film. 展开更多
关键词 NONLOCAL ELASTICITY EPITAXIAL strain film Thin Films
Fujita-type Phenomenon of the Nonlocal Diffusion Equations with Localized Source
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作者 Lili YANG Zhongping LI 《数学研究及应用:英文版》 CSCD 2019年第2期171-180,共10页
In this paper, we investigate the Cauchy problem for the nonlocal diffusion system with localized source ut = J*u-u + a(x)v~p, v_t = J*v-v + a(x)u~q. We first prove that the Fujita curve is(pq)_c*-= 1+max{p+1, q+1}bas... In this paper, we investigate the Cauchy problem for the nonlocal diffusion system with localized source ut = J*u-u + a(x)v~p, v_t = J*v-v + a(x)u~q. We first prove that the Fujita curve is(pq)_c*-= 1+max{p+1, q+1}based on whether there exist global solutions, thatis, if 1 < pq(pq)_c,then every nonnegative solution blows up in finite time, but for pq >(pq)_c,there exist both global and non-global solutions to the problem. Furthermore, we establish the secondary critical curve on the space-decay of initial value at infinity. 展开更多
关键词 NONLOCAL diffusion system Fujita CRITICAL CURVE secondary CRITICAL CURVE global EXISTENCE BLOW-UP
Nonlinear free vibration of piezoelectric cylindrical nanoshells 预览
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作者 Yanqing WANG Yunfei LIU J. W. ZU 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第5期601-620,共20页
The nonlinear vibration characteristics of the piezoelectric circular cylindri- cal nanoshells resting on an elastic foundation are analyzed. The small scale effect and thermo-electro-mechanical loading are taken into... The nonlinear vibration characteristics of the piezoelectric circular cylindri- cal nanoshells resting on an elastic foundation are analyzed. The small scale effect and thermo-electro-mechanical loading are taken into account. Based on the nonlocal elastic- ity theory and Donnell’s nonlinear shell theory, the nonlinear governing equations and the corresponding boundary conditions are derived by employing Hamilton’s principle. Then, the Galerkin method is used to transform the governing equations into a set of ordinary differential equations, and subsequently, the multiple-scale method is used to obtain an approximate analytical solution. Finally, an extensive parametric study is conducted to examine the effects of the nonlocal parameter, the external electric potential, the temperature rise, and the Winkler-Pasternak foundation parameters on the nonlinear vibration characteristics of circular cylindrical piezoelectric nanoshells. 展开更多
关键词 PIEZOELECTRIC CYLINDRICAL NANOSHELL NONLINEAR vibration Donnell's NONLINEAR shell THEORY nonlocal elasticity THEORY multiple-scale method size effect
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一个非局部平面凸曲线的发展演化 预览
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作者 邢巧芳 《河南科技大学学报:自然科学版》 CAS 北大核心 2019年第2期87-90,110共5页
针对受外力影响的曲线发展问题,研究了一种新的非局部平面凸曲线的发展演化。在演化过程中,曲线保持凸性,所围区域的面积增大而曲线的长度减少。在Hausdorff测度下,当t趋向于无穷大时,曲线收敛到有限圆。
关键词 非局部 凸曲线 支撑函数 发展演化 曲率半径
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A nonlocal Burgers equation in atmospheric dynamical system and its exact solutions
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作者 刘希忠 俞军 +1 位作者 楼智美 钱贤民 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期189-194,共6页
From a two-vortex interaction model in atmospheric and oceanic systems, a nonlocal counterpart with shifted parity and delayed time reversal is derived by a simple AB reduction. To obtain some approximate analytic sol... From a two-vortex interaction model in atmospheric and oceanic systems, a nonlocal counterpart with shifted parity and delayed time reversal is derived by a simple AB reduction. To obtain some approximate analytic solutions of this nonlocal system, the multi-scale expansion method is applied to get an AB-Burgers system. Various exact solutions of the AB-Burgers equation, including elliptic periodic waves, kink waves and solitary waves, are obtained and shown graphically.To show the applications of these solutions in describing correlated events, a simple approximate solution for the two-vortex interaction model is given to show two correlated dipole blocking events at two different places. Furthermore, symmetry reduction solutions of the nonlocal AB-Burgers equation are also given by using the standard Lie symmetry method. 展开更多
关键词 AB–BA EQUIVALENCE principle NONLOCAL BURGERS equation periodic waves
Deep postbuckling and nonlinear bending behaviors of nanobeams with nonlocal and strain gradient effects 预览
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作者 Bo ZHANG Huoming SHEN +2 位作者 Juan LIU Yuxing WANG Yingrong ZHANG 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第4期515-548,共34页
In this paper,multi-scale modeling for nanobeams with large deflection is conducted in the framework of the nonlocal strain gradient theory and the Euler-Bernoulli beam theory with exact bending curvature.The proposed... In this paper,multi-scale modeling for nanobeams with large deflection is conducted in the framework of the nonlocal strain gradient theory and the Euler-Bernoulli beam theory with exact bending curvature.The proposed size-dependent nonlinear beam model incorporates structure-foundation interaction along with two small scale param-eters which describe the stiffness-softening and stiffness-hardening size effects of nano-materials,respectively.By applying Hamilton’s principle,the motion equation and the associated boundary condition are derived.A two-step perturbation method is intro-duced to handle the deep postbuckling and nonlinear bending problems of nanobeams analytically.Afterwards,the influence of geometrical,material,and elastic foundation parameters on the nonlinear mechanical behaviors of nanobeams is discussed.Numerical results show that the stability and precision of the perturbation solutions can be guaran-teed,and the two types of size effects become increasingly important as the slenderness ratio increases.Moreover,the in-plane conditions and the high-order nonlinear terms appearing in the bending curvature expression play an important role in the nonlinear behaviors of nanobeams as the maximum deflection increases. 展开更多
关键词 nanobeam NONLOCAL strain gradient theory TWO-STEP PERTURBATION method deep POSTBUCKLING
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Pull-in Instability Analysis of Nanoelectromechanical Rectangular Plates Including the Intermolecular, Hydrostatic, and Thermal Actuations Using an Analytical Solution Methodology
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作者 F.Samadani R.Ansari +1 位作者 K.Hosseini A.Zabihi 《理论物理通讯:英文版》 SCIE CAS CSCD 2019年第3期349-356,共8页
The current paper presents a thorough study on the pull-in instability of nanoelectromechanical rectangular plates under intermolecular, hydrostatic, and thermal actuations. Based on the Kirchhoff theory along with Er... The current paper presents a thorough study on the pull-in instability of nanoelectromechanical rectangular plates under intermolecular, hydrostatic, and thermal actuations. Based on the Kirchhoff theory along with Eringen’s nonlocal elasticity theory, a nonclassical model is developed. Using the Galerkin method(GM), the governing equation which is a nonlinear partial differential equation(NLPDE) of the fourth order is converted to a nonlinear ordinary differential equation(NLODE) in the time domain. Then, the reduced NLODE is solved analytically by means of the homotopy analysis method. At the end, the effects of model parameters as well as the nonlocal parameter on the deflection, nonlinear frequency, and dynamic pull-in voltage are explored. 展开更多
关键词 Nanoelectromechanical rectangular plates PULL-IN instability Kirchhoff THEORY Eringen's nonlocal elasticity THEORY HOMOTOPY ANALYSIS method
一个具有附益性及保序性算子的形态学非局部拓展 预览
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作者 孙忠贵 高新波 +2 位作者 张冬梅 李洁 王颖 《电子学报》 CSCD 北大核心 2018年第8期1969-1975,共7页
近年,形态学非局部拓展工作在图像处理领域受到众多关注.而附益性算子是经典形态学的最基本形式,也是形态学分析方法最重要的变换工具.为此,一些研究者就形态学非局部拓展中如何保持算子的附益性开展工作.本文从理论及实例两个方面说明... 近年,形态学非局部拓展工作在图像处理领域受到众多关注.而附益性算子是经典形态学的最基本形式,也是形态学分析方法最重要的变换工具.为此,一些研究者就形态学非局部拓展中如何保持算子的附益性开展工作.本文从理论及实例两个方面说明,相关拓展工作为保持算子的附益性而丢失了保序性的不足;进一步,通过设计非局部权值的获取过程,并结合现有工作,本文提出了一个新的形态学非局部拓展,并定理证明了所得算子同时具备附益性及保序性两个重要性质;人工合成图像及自然图像上的仿真实验也表明了本文所提算法的有效性. 展开更多
关键词 形态学 非局部 附益性 保序性 腐蚀 膨胀
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Improved Weight Function for Nonlocal Means Image Denoising 预览
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作者 许建楼 郝岩 《东华大学学报:英文版》 EI CAS 2018年第5期394-398,共5页
The nonlocal means(NLM)has been widely used in image processing.In this paper,we introduce a modified weight function for NLM denoising,which will compute the nonlocal similarities among the pre-processing pixel patch... The nonlocal means(NLM)has been widely used in image processing.In this paper,we introduce a modified weight function for NLM denoising,which will compute the nonlocal similarities among the pre-processing pixel patches instead of the commonly used similarity measure based on noisy observations.By the law of large number,the norm for the pre-processing pixel patches is closer to the norm of the original clean pixel patches,so the proposed weight functions are more optimized and the selected similar patches are more accurate.Experimental results indicate the proposed algorithm achieves better restored results compared to the classical NLM s method. 展开更多
关键词 image DENOISING NONLOCAL means(NLM) WEIGHT PATCH SIMILARITY
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Controllable wave propagation in a weakly nonlinear monoatomic lattice chain with nonlocal interaction and active control 预览
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作者 Jiao WANG WeijianZHOU +3 位作者 Yang HUANG Chaofeng LYU Weiqiu CHEN WeiqiuZHU 《应用数学和力学:英文版》 SCIE EI CSCD 2018年第8期1059-1070,共12页
The one-dimensional monoatomic lattice chain connected by nonlinear springs is investigated,and the asymptotic solution is obtained through the Lindstedt-Poincar′e perturbation method.The dispersion relation is deriv... The one-dimensional monoatomic lattice chain connected by nonlinear springs is investigated,and the asymptotic solution is obtained through the Lindstedt-Poincar′e perturbation method.The dispersion relation is derived with the consideration of both the nonlocal and the active control effects.The numerical results show that the nonlocal effect can effectively enhance the frequency in the middle part of the dispersion curve.When the nonlocal effect is strong enough,zero and negative group velocities will be evoked at different points along the dispersion curve,which will provide different ways of transporting energy including the forward-propagation,localization,and backwardpropagation of wavepackets related to the phase velocity.Both the nonlinear effect and the active control can enhance the frequency,but neither of them is able to produce zero or negative group velocities.Specifically,the active control enhances the frequency of the dispersion curve including the point at which the reduced wave number equals zero,and therefore gives birth to a nonzero cutoff frequency and a band gap in the low frequency range.With a combinational adjustment of all these effects,the wave propagation behaviors can be comprehensively controlled,and energy transferring can be readily manipulated in various ways. 展开更多
关键词 monoatomic LATTICE CHAIN NONLOCAL effect NEGATIVE group velocity active control band gap
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Frequency equations of nonlocal elastic micro/nanobeams with the consideration of the surface effects 预览
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作者 H.S.ZHAO Y.ZHANG S.T.LIE 《应用数学和力学:英文版》 SCIE EI CSCD 2018年第8期1089-1102,共14页
A nonlocal elastic micro/nanobeam is theoretically modeled with the consideration of the surface elasticity,the residual surface stress,and the rotatory inertia,in which the nonlocal and surface effects are considered... A nonlocal elastic micro/nanobeam is theoretically modeled with the consideration of the surface elasticity,the residual surface stress,and the rotatory inertia,in which the nonlocal and surface effects are considered.Three types of boundary conditions,i.e.,hinged-hinged,clamped-clamped,and clamped-hinged ends,are examined.For a hinged-hinged beam,an exact and explicit natural frequency equation is derived based on the established mathematical model.The Fredholm integral equation is adopted to deduce the approximate fundamental frequency equations for the clamped-clamped and clamped-hinged beams.In sum,the explicit frequency equations for the micro/nanobeam under three types of boundary conditions are proposed to reveal the dependence of the natural frequency on the effects of the nonlocal elasticity,the surface elasticity,the residual surface stress,and the rotatory inertia,providing a more convenient means in comparison with numerical computations. 展开更多
关键词 FREDHOLM INTEGRAL equation micro/nanobeam natural frequency NONLOCAL ELASTICITY surface effect
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Experimental test of generalized Hardy’s paradox
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作者 Yi-Han Luo Hong-Yi Su +7 位作者 He-Liang Huang Xi-Lin Wang Tao Yang Li Li Nai-Le Liu Jing-Ling Chen Chao-Yang Lu Jian-Wei Pan 《科学通报:英文版》 SCIE EI CSCD 2018年第24期1611-1615,共5页
Since the pillars of quantum theory were established, it was already noted that quantum physics may allow certain correlations defying any local realistic picture of nature, as first recognized by Einstein,Podolsky an... Since the pillars of quantum theory were established, it was already noted that quantum physics may allow certain correlations defying any local realistic picture of nature, as first recognized by Einstein,Podolsky and Rosen. These quantum correlations, now termed quantum nonlocality and tested by violation of Bell’s inequality that consists of statistical correlations fulfilling local realism, have found loophole-free experimental confirmation. A more striking way to demonstrate the conflict exists, and can be extended to the multipartite scenario. Here we report experimental confirmation of such a striking way, the multipartite generalized Hardy’s paradoxes, in which no inequality is used and the conflict is stronger than that within just two parties. The paradoxes we consider here belong to a general framework [S.-H. Jiang et al., Phys. Rev. Lett. 120(2018) 050403], including previously known multipartite extensions of Hardy’s original paradox as special cases. The conflict shown here is stronger than in previous multipartite Hardy’s paradox. Thus, the demonstration of Hardy-typed quantum nonlocality becomes sharper than ever. 展开更多
关键词 Hardy's PARADOX Bell's inequality NONLOCAL CORRELATIONS MULTIPARTITE ENTANGLEMENT
Nonlocal buckling of embedded magnetoelectroelastic sandwich nanoplate using refined zigzag theory 预览
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作者 A.GHORBANPOUR-ARANI F.KOLAHDOUZAN M.ABDOLLAHIAN 《应用数学和力学:英文版》 SCIE EI CSCD 2018年第4期529-546,共18页
This paper is concerned with a buckling analysis of an embedded nanoplate integrated with magnetoelectroelastic(MEE)layers based on a nonlocal magnetoelectroe-lasticity theory.A surrounding elastic medium is simulated... This paper is concerned with a buckling analysis of an embedded nanoplate integrated with magnetoelectroelastic(MEE)layers based on a nonlocal magnetoelectroe-lasticity theory.A surrounding elastic medium is simulated by the Pasternak foundation that considers both shear and normal loads.The sandwich nanoplate(SNP)consists of a core that is made of metal and two MEE layers on the upper and lower surfaces of the core made of BaTiO3/CoFe2O4.The refined zigzag theory(RZT)is used to model the SNP subject to both external electric and magnetic potentials.Using an energy method and Hamilton’s principle,the governing motion equations are obtained,and then solved analytically.A detailed parametric study is conducted,concentrating on the combined effects of the small scale parameter,external electric and magnetic loads,thicknesses of MEE layers,mode numbers,and surrounding elastic medium.It is concluded that in-creasing the small scale parameter decreases the critical buckling loads. 展开更多
关键词 SANDWICH nanoplate(SNP) refined ZIGZAG theory(RZT) nonlocal magne-toelectroelasticity THEORY buckling MAGNETOSTRICTIVE layer
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Small scale effects on buckling and postbuckling behaviors of axially loaded FGM nanoshells based on nonlocal strain gradient elasticity theory 预览
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作者 S.SAHMANI A.M.FATTAHI 《应用数学和力学:英文版》 SCIE EI CSCD 2018年第4期561-580,共20页
By means of a comprehensive theory of elasticity,namely,a nonlocal strain gradient continuum theory,size-dependent nonlinear axial instability characteristics of cylindrical nanoshells made of functionally graded mate... By means of a comprehensive theory of elasticity,namely,a nonlocal strain gradient continuum theory,size-dependent nonlinear axial instability characteristics of cylindrical nanoshells made of functionally graded material(FGM)are examined.To take small scale effects into consideration in a more accurate way,a nonlocal stress field parameter and an internal length scale parameter are incorporated simultaneously into an exponential shear deformation shell theory.The variation of material properties asso-ciated with FGM nanoshells is supposed along the shell thickness,and it is modeled based on the Mori-Tanaka homogenization scheme.With a boundary layer theory of shell buck-ling and a perturbation-based solving process,the nonlocal strain gradient load-deflection and load-shortening stability paths are derived explicitly.It is observed that the strain gradient size effect causes to the increases of both the critical axial buckling load and the width of snap-through phenomenon related to the postbuckling regime,while the nonlocal size dependency leads to the decreases of them.Moreover,the influence of the nonlocal type of small scale effect on the axial instability characteristics of FGM nanoshells is more than that of the strain gradient one. 展开更多
关键词 nanomechanics functionally GRADED material(FGM) NONLOCAL strain gra-dient theory nonlinear instability perturbation technique
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Semi-analytic solution of Eringen’s two-phase local/nonlocal model for Euler-Bernoulli beam with axial force 预览
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作者 Licheng MENG Dajun ZOU +4 位作者 Huan LAI Zili GUO Xianzhong HE Zhijun XIE Cunfa GAO 《应用数学和力学:英文版》 SCIE EI CSCD 2018年第12期1805-1824,共20页
Eringen’s two-phase local/nonlocal model is applied to an Euler-Bernoulli nanobeam considering the bending-induced axial force,where the contribution of the axial force to bending moment is calculated on the deformed... Eringen’s two-phase local/nonlocal model is applied to an Euler-Bernoulli nanobeam considering the bending-induced axial force,where the contribution of the axial force to bending moment is calculated on the deformed state.Basic equations for the corresponding one-dimensional beam problem are obtained by degenerating from the three-dimensional nonlocal elastic equations.Semi-analytic solutions are then presented for a clamped-clamped beam subject to a concentrated force and a uniformly distributed load,respectively.Except for the traditional essential boundary conditions and those required to be satisfied by transferring an integral equation to its equivalent differential form,additional boundary conditions are needed and should be chosen with great caution,since numerical results reveal that non-unique solutions might exist for a nonlinear problem if inappropriate boundary conditions are used.The validity of the solutions is examined by plotting both sides of the original integro-differential governing equation of deflection and studying the error between both sides.Besides,an increase in the internal characteristic length would cause an increase in the deflection and axial force of the beam. 展开更多
关键词 NONLOCAL ELASTICITY internal characteristic length size effect nanobeam AXIAL force UNIQUE solution
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N-soliton solutions for the nonlocal two-wave interaction system via the Riemann–Hilbert method
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作者 徐思齐 耿献国 《中国物理B:英文版》 SCIE EI CAS CSCD 2018年第12期157-163,共7页
In this paper, a nonlocal two-wave interaction system from the Manakov hierarchy is investigated via the Riemann–Hilbert approach. Based on the spectral analysis of the Lax pair, a Riemann–Hilbert problem for the no... In this paper, a nonlocal two-wave interaction system from the Manakov hierarchy is investigated via the Riemann–Hilbert approach. Based on the spectral analysis of the Lax pair, a Riemann–Hilbert problem for the nonlocal two-wave interaction system is constructed. By discussing the solutions of this Riemann–Hilbert problem in both the regular and nonregular cases, we explicitly present the N-soliton solution formula of the nonlocal two-wave interaction system. Moreover,the dynamical behaviour of the single-soliton solution is shown graphically. 展开更多
关键词 NONLOCAL two-wave interaction SYSTEM Riemann–Hilbert problem N-SOLITON solutions
Peridynamics versus XFEM:a comparative study for quasistatic crack problems
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作者 Jinhai ZHAO Hesheng TANG Songtao XUE 《结构与土木工程前沿:英文版》 EI CSCD 2018年第4期548-557,共10页
Peridynamics (PD)is a nonlocal continuum theory based on integro-differential equations without spatial derivatives.The fracture criterion is implicitly incorporated in the PD theory and fracture is a natural outcome ... Peridynamics (PD)is a nonlocal continuum theory based on integro-differential equations without spatial derivatives.The fracture criterion is implicitly incorporated in the PD theory and fracture is a natural outcome of the simulation.However,capturing of complex mixed-mode crack patterns has been proven to be difficult with PD.On the other hand,the extended finite element method (XFEM)is one of the most popular methods for fracture which allows crack propagation with minimal remeshing.It requires a fracture criterion which is independent of the underlying discretization though a certain refinement is needed in order to obtain suitable results.This article presents a comparative study between XFEM and PD.Therefore,two examples are studied.The first example is crack propagation in a double notched specimen under uniaxial tension with different crack spacings in loading direction.The second example is the specimens with two center cracks.The results show that PD as well as XFEM are well suited to capture this type of behaviour. 展开更多
关键词 XFEM peridynamic BILATERAL CRACK parallel double cracks NONLOCAL theory
改进相似性度量准则的SAR-BM3D相干斑抑制算法 预览 被引量:1
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作者 鲁自立 贾鑫 曾创展 《国外电子测量技术》 2017年第11期21-25,共5页
针对三维块匹配(BM3D)算法在合成孔径雷达(SAR)图像相干斑抑制时存在块相似性度量不准确的问题,提出一种改进广义似然比准则(GLR)的SAR-BM3D相干斑抑制算法。该算法根据在光学图像去噪效果良好的BM3D算法,以变换域方法和非局部思... 针对三维块匹配(BM3D)算法在合成孔径雷达(SAR)图像相干斑抑制时存在块相似性度量不准确的问题,提出一种改进广义似然比准则(GLR)的SAR-BM3D相干斑抑制算法。该算法根据在光学图像去噪效果良好的BM3D算法,以变换域方法和非局部思想为基础,考虑SAR图像相干斑特性,采用概率相似性度量方法用于块匹配步骤,从而达到较好的相干斑抑制效果。实验证明,提出的算法对SAR图像的相干斑抑制可以获得更高的信噪比和更好的视觉效果。 展开更多
关键词 合成孔径雷达 SAR图像相干斑抑制 三维块匹配 广义似然比 非局部 概率相似性
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基于非局部自适应字典的乘性噪声去除 预览
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作者 陈利霞 何成凤 王学文 《计算机工程与设计》 北大核心 2017年第9期2451-2456,共6页
为更好保护图像的重要信息,在非局部模型及BF模型的基础上,提出一种乘性噪声去除算法。利用对数变换将乘性噪声转换为加性噪声,结合PCA稀疏字典和迭代收缩算法更新稀疏编码,用牛顿迭代法得到对数域中的去噪图像,通过指数函数以及误差校... 为更好保护图像的重要信息,在非局部模型及BF模型的基础上,提出一种乘性噪声去除算法。利用对数变换将乘性噪声转换为加性噪声,结合PCA稀疏字典和迭代收缩算法更新稀疏编码,用牛顿迭代法得到对数域中的去噪图像,通过指数函数以及误差校正得到实数域中的去噪图像。实验结果表明,该算法能够有效去除噪声,较好保留图像的边缘、细节和纹理信息。 展开更多
关键词 乘性噪声 字典学习 稀疏表示 非局部 迭代收缩算法
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