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Numerical solutions for cracks in an elastic half-plane 预览
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作者 N.R.F.Elfakhakhre N.M.A.Nik Long Z.K.Eshkuvatov 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第1期212-227,I0006共17页
The behavior of the stress intensity factor at the tips of cracks subjected to uniaxial tension σχ^∞= p with traction-free boundary condition in half-plane elasticity is investigated. The problem is formulated into... The behavior of the stress intensity factor at the tips of cracks subjected to uniaxial tension σχ^∞= p with traction-free boundary condition in half-plane elasticity is investigated. The problem is formulated into singular integral equations with the distribution dislocation function as unknown. In the formulation, we make used of a modified complex potential. Based on the appropriate quadrature formulas together with a suitable choice of collocation points, the singular integral equations are reduced to a system of linear equations for the unknown coefficients. Numerical examples show that the values of the stress intensity factor are influenced by the distance from the cracks to the boundary of the half-plane and the configuration of the cracks. 展开更多
关键词 ELASTIC HALF-PLANE Multiple cracks SINGULAR integral equation Sine-shaped CRACK
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Compactness for the commutators of multilinear singular integral operators with non-smooth kernels 预览
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作者 BU Rui CHEN Jie-cheng 《高校应用数学学报:英文版(B辑)》 SCIE CSCD 2019年第1期55-75,共21页
In this paper,the behavior for commutators of a class of bilinear singular integral operators associated with non-smooth kernels on the product of weighted Lebesgue spaces is considered.By some new maximal functions t... In this paper,the behavior for commutators of a class of bilinear singular integral operators associated with non-smooth kernels on the product of weighted Lebesgue spaces is considered.By some new maximal functions to control the commutators of bilinear singular integral operators and CMO(Rn)functions,compactness for the commutators is proved. 展开更多
关键词 singular integral OPERATOR maximal function weighted norm inequality COMMUTATOR compact OPERATOR
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On the Structures of K2(Z[G]), G a Finite Abelian p-Group
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作者 Yakun Zhang Guoping Tang Hong Chen 《代数集刊:英文版》 SCIE CSCD 2019年第1期105-112,共8页
Let G be a finite abelian p-group,Г the maximal Z-order of Z[G]. We prove that the 2-primary torsion subgroups of K2Z[G]) and K2(Г)are isomorphic when p ≡ 3, 5, 7 (mod 8, and K2(Z[G])■zZ[1/p] is isomorphic to K2(... Let G be a finite abelian p-group,Г the maximal Z-order of Z[G]. We prove that the 2-primary torsion subgroups of K2Z[G]) and K2(Г)are isomorphic when p ≡ 3, 5, 7 (mod 8, and K2(Z[G])■zZ[1/p] is isomorphic to K2(Г)■zZ[1/p] when p = 2,3,5,7. As an application, we give the structure of K2(Z[G]) for G a cyclic p-group or an elementary abelian p-group. 展开更多
关键词 ALGEBRAIC K-THEORY K2-group INTEGRAL group RING
一种控制舱积分漂移测试技术
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作者 程丰 李恒松 +1 位作者 侯生彪 齐军利 《仪表技术》 2019年第2期27-30,共4页
针对控制舱环境试验检测系统研制过程中遇到的积分漂移测试不一致问题,研究控制舱积分电路及积分漂移产生的原理,分析控制舱环境试验检测系统积分漂移测试程序机理,提出了一种控制舱积分漂移测试技术,对比控制舱环境试验检测系统测试数... 针对控制舱环境试验检测系统研制过程中遇到的积分漂移测试不一致问题,研究控制舱积分电路及积分漂移产生的原理,分析控制舱环境试验检测系统积分漂移测试程序机理,提出了一种控制舱积分漂移测试技术,对比控制舱环境试验检测系统测试数据与示波记录仪监测数据计算结果,确认该测试数据与示波记录仪监测数据计算结果更加接近。 展开更多
关键词 积分 控制舱 漂移
Monitoring and analysis of mining 3D deformation by multiplatform SAR images with the probability integral method
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作者 Meinan ZHENG Kazhong DENG +1 位作者 Hongdong FAN Jilei HUANG 《地球科学前沿:英文版》 SCIE CAS CSCD 2019年第1期169-179,共11页
Only one-dimensional (1D)deformation along the radar line of sight (LOS)can be obtained using differential interferometry synthetic aperture radar (D-InSAR),and D-InSAR observation is insensitive to deformation in the... Only one-dimensional (1D)deformation along the radar line of sight (LOS)can be obtained using differential interferometry synthetic aperture radar (D-InSAR),and D-InSAR observation is insensitive to deformation in the north direction.This study inferred three-dimensional (3D)deformation of a mining subsidence basin by combining the north-south deformation predicted by a probability integral method with the LOS deformation obtained by D-InSAR.The 15235 working face in Fengfeng mining area (Hebei Province,China)was used as the object of study.The north-south horizontal movement was predicted by the probability integral method according to the site's geological and mining conditions.Then,the vertical and east-west deformation fields were solved by merging ascend-orbit RadarSAT-2, descend-orbit TerraSAR,and predicted north-south deformation based on a least squares method.Comparing with the leveling data,the results show that the vertical deformation accuracy of the experimental method is better than the inversed vertical deformation neglecting the horizontal deformation.Finally,the impact of the relationship between the azimuth of the working face and the SAR imaging geometry on the monitoring of the mining subsidence basin was analyzed.The results can be utilized in monitoring mining subsidence basins by single SAR image sources. 展开更多
关键词 D-INSAR ascend-descend ORBIT data SUBSIDENCE prediction probability integral method 3D DEFORMATION
关于定义在单位圆上的复函数的拟Grüss型伴随不等式
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作者 朱建 陈丽娟 薛巧玲 《高等学校计算数学学报》 CSCD 北大核心 2019年第2期97-106,共10页
Several companions of quasi Grüss type inequalities for the Riemann-Stieltjes integral of continuous complex valued integrands defined on the complex unit circle C[0,2π] are given,while the integrator u is the c... Several companions of quasi Grüss type inequalities for the Riemann-Stieltjes integral of continuous complex valued integrands defined on the complex unit circle C[0,2π] are given,while the integrator u is the case of bounded variation,Lipschitzian,respectively.Some inequalities are generalized for second derivative. 展开更多
关键词 Grüss type INEQUALITIES Riemann-Stieltjes INTEGRAL unit circle
A NECESSARY CONDITION FOR CERTAIN INTEGRAL EQUATIONS WITH NEGATIVE EXPONENTS 预览
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作者 许建开 谭忠 +1 位作者 王伟伟 熊泽鹏 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第1期284-296,共13页
This paper is devoted to studying the existence of positive solutions for the following integral system {u(x)=∫Rn|x-y|λv-q(y)dy, ∫Rn|x-y|λv-p(y)dy,p,q>0,λ∈(0,∞),n≥1.It is shown that if(u,v) is a pair of pos... This paper is devoted to studying the existence of positive solutions for the following integral system {u(x)=∫Rn|x-y|λv-q(y)dy, ∫Rn|x-y|λv-p(y)dy,p,q>0,λ∈(0,∞),n≥1.It is shown that if(u,v) is a pair of positive Lebesgue measurable solutions of this integral system, then 1/(p-1)+1/(q-1)=λ/n, which is different from the well-known case of the Lane-Emden system and its natural extension, the Hardy-Littlewood-Sobolev type integral equations. 展开更多
关键词 integral equations Lane-Emden system CONFORMAL INVARIANCE positive solutions existence
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整体式教学楼教室利用率分析与探讨——以天津师范大学为例 预览
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作者 王健 《中国轻工教育》 2019年第2期55-58,78共5页
如何合理规划教学资源,提高教学资源的利用效率已成为一个备受瞩目的问题,其对推进绿色校园建设,促进我国高等学校的办学水平和教育质量有着重要的意义。教室作为学校教育中最基本也是最重要的教学资源,合理安排高校的教室资源,提高其... 如何合理规划教学资源,提高教学资源的利用效率已成为一个备受瞩目的问题,其对推进绿色校园建设,促进我国高等学校的办学水平和教育质量有着重要的意义。教室作为学校教育中最基本也是最重要的教学资源,合理安排高校的教室资源,提高其利用效率也就显得尤为重要。本文以天津师范大学劝学楼为调查研究对象,较为全面地分析整体式教学楼的利用现状及存在的问题,提出相关对策,使教室资源更好地为高校师生服务。 展开更多
关键词 整体式 教室 利用率
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Convergence of truncated rough singular integrals supported by subvarieties on Triebel-Lizorkin spaces
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作者 Feng LIU Qingying XUE Kozo YABUTA 《中国数学前沿:英文版》 SCIE CSCD 2019年第3期591-604,共14页
Let Ω be a function of homogeneous of degree zero and satisfy the cancellation condition on the unit sphere. Suppose that h is a radial function. Let Th,Ω,φ be the classical singular Radon transform, and let Th^ε,... Let Ω be a function of homogeneous of degree zero and satisfy the cancellation condition on the unit sphere. Suppose that h is a radial function. Let Th,Ω,φ be the classical singular Radon transform, and let Th^ε,Ω,φ be its truncated operator with rough kernels associated to polynomial mapping which is defined by Th^ε,Ω,φf(x)=|f|y|>εf(x-φ(y))h(|y|)Ω(y)|y|^-ndy|.In this paper, we show that for any a ∈(-∞,∞) and (p, q) satisfying certain index condition, the operator Th^ε,Ω,φ enjoys the following convergence properties lim ε→0||Th^ε,Ω,φf-Th,Ω,φf||Fα^p,q(R^d)= 0 and limε→0||Th^ε,Ω,φf-Th,Ω,φf||Bα^p,q(R^d)=0, provided that Ω∈L(log+ L)β(S^n-1) for some β∈(0,1], or Ω∈H^1(S^n-1), or Ω∈(U1<q<∞Bq^(0,0)(S^n-1)). 展开更多
关键词 SINGULAR RADON transform TRUNCATED SINGULAR integral ROUGH kernel CONVERGENCE
Plane Analysis for an Inclusion in ID Hexagonal Quasicrys tai Using the Hyp er singular Integral Equation Method
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作者 Fei Lou Ting Cao +1 位作者 Taiyan Qin Chunhui Xu 《固体力学学报:英文版》 SCIE EI CSCD 2019年第2期249-260,共12页
A model of a thin elastic inclusion embedded in an infinite ID hexagonal quasicrystal is discussed. The atomic arrangements of the matrix and the inclusion are both periodic along the xi-direction and quasiperiodic al... A model of a thin elastic inclusion embedded in an infinite ID hexagonal quasicrystal is discussed. The atomic arrangements of the matrix and the inclusion are both periodic along the xi-direction and quasiperiodic along the a;2-direction in the oxiX2-coordinate system. Using the hypersingular integral equation method, the inclusion problem is reduced to solving a set of hypersingular integral equations. Based on the exact analytical solution of the singular phonon and phason stresses near the inclusion front, a numerical method of the hypersingular integral equation is proposed using the finite-part integral method. Finally, the numerical solutions for the phonon and phason stress intensity factors of some examples are given. 展开更多
关键词 Elastic INCLUSION ID HEXAGONAL QUASICRYSTAL Hypersingular integral equations
基于综合素质积分的高校图书馆阅读推广模式实践和启示——以广东科学技术职业学院图书馆为例
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作者 余和剑 《图书馆学研究》 CSSCI 北大核心 2019年第12期91-94,F0003共5页
积分制是运用量化的方法对工作或表现给予适度奖惩的一种管理机制,它引起了图书馆领域专家学者的注意,正逐渐成为图书馆学界关注的聚焦点之一,图书馆领域专家学者从不同视角开展了诸多有益探索。文章立足近一年来基于综合素质积分的阅... 积分制是运用量化的方法对工作或表现给予适度奖惩的一种管理机制,它引起了图书馆领域专家学者的注意,正逐渐成为图书馆学界关注的聚焦点之一,图书馆领域专家学者从不同视角开展了诸多有益探索。文章立足近一年来基于综合素质积分的阅读推广模式在高校图书馆的应用实践,在介绍项目概况、实施案例及取得成效的基础上,总结该模式的成果经验,以期为高校图书馆同仁在开展阅读推广工作时提供参考和借鉴。实践证明,基于学生综合素质积分的阅读推广模式在提高图书馆利用率和提升图书馆活动的用户关注度等方面有着明显的推动作用。 展开更多
关键词 综合素质 积分 高校图书馆 阅读推广
Combined approach for analysing evolutionary power spectra of a track-soil system under moving random loads 预览
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作者 Y.Zhao L.T.Si H.Ouyang 《力学学报:英文版》 SCIE EI CAS CSCD 2019年第3期674-690,共17页
The pseudo-excitation method combined with the integral transform method (PEM-ITM) is presented to investigate the ground vibration of a coupled track-soil system induced by moving random loads. Commonly in the track ... The pseudo-excitation method combined with the integral transform method (PEM-ITM) is presented to investigate the ground vibration of a coupled track-soil system induced by moving random loads. Commonly in the track model, the rail, sleepers, rail pads, and ballast are modelled as an infinite Euler beam, discretely distributed masses, discretely distributed vertical springs, and a viscoelastic layer, respectively. The soil is regarded as a homogenous isotropic half-space coupled with the track using the boundary condition at the surface of the ground. By introducing a pseudo-excitation, the random vibration analysis of the coupled system is converted into a harmonic analysis. The analytical form of evolutionary power spectral density responses of the simplified coupled track-soil system under a random moving load is derived in the frequency/wavenumber domain by PEM-ITM. In the numerical examples, the effects of different parameters, such as the moving speed, the soil properties, and the coherence of moving loads, on the ground response are investigated. 展开更多
关键词 Track-soil system MOVING random loads EVOLUTIONARY POWER spectrum Pseudo-excitation METHOD Integral TRANSFORM METHOD Vibration transmission
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QUANTITATIVE WEIGHTED BOUNDS FOR A CLASS OF SINGULAR INTEGRAL OPERATORS 预览
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作者 高文华 胡国恩 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第4期1149-1162,共14页
In this article, the authors consider the weighted bounds for the singular integral operator defined by TAf(x)=p.v.∫Rn Ω(x-y)/|x-y|n+1(A(x)-A(y)-▽A(y))f(y)dy,where Ω is homogeneous of degree zero and has vanishing... In this article, the authors consider the weighted bounds for the singular integral operator defined by TAf(x)=p.v.∫Rn Ω(x-y)/|x-y|n+1(A(x)-A(y)-▽A(y))f(y)dy,where Ω is homogeneous of degree zero and has vanishing moment of order one, and A is a function on Rn such that ▽A ∈ BMO(R^n). By sparse domination, the authors obtain some qua nt itative weighted bounds for Ta when Q satisfies regularity condition of L^τ-Dini type for some r∈(1,∞). 展开更多
关键词 Singular integral operator SPARSE DOMINATION Ap constant MAXIMAL OPERA TOR
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The surface current method in gray Dancoff factor calculation 预览
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作者 Omid Safarzadeh 《核技术:英文版》 SCIE CAS CSCD 2019年第6期28-34,共7页
The Dancoff correction is important in the calculation of the effective cross section of resonant isotopes in a heterogeneous system. Although the neutron current method is a simple and straightforward approach to est... The Dancoff correction is important in the calculation of the effective cross section of resonant isotopes in a heterogeneous system. Although the neutron current method is a simple and straightforward approach to estimate the Dancoff factor, its use is limited to the black Dancoff factor. In this paper, we expand the current method used to determine both the black and gray Dancoff factors. The method developed also relies on a neutron transport solver, where a fixed source on a fuel rod surface has an outward direction, a cosine distribution, and a constant shape. The detector is located on the surface of the rods to measure incoming and outgoing currents;therefore, there is no need to calculate the chord length, and the development, validation, and verification of the code can be omitted. The mathematical foundation of the suggested method is derived using the integral transport equation. The effects of the moderator and lattice configuration are followed by a sensitivity analysis of the Dancoff factor for several problems, including pressurized water reactor and cluster fuel assemblies. The maximum and average relative errors of the calculated results are approximately 0.3% and 0.05%, respectively. 展开更多
关键词 BLACK Dancoff GRAY Dancoff INTEGRAL TRANSPORT EQUATION Interface current TRANSPORT SOLVER
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积分的整体性 预览 被引量:1
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作者 吕中学 《高等数学研究》 2019年第1期126-128,共3页
本文从积分的整体性对数学分析中积分学部分的教和学,给出一些建议,即整体把握积分思想,整体把握积分脉络,整体把握积分计算,整体把握积分之间的联系,使教和学更加有的放矢.
关键词 积分 整体性 教和学
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NUMERICAL ANALYSIS FOR VOLTERRA INTEGRAL EQUATION WITH TWO KINDS OF DELAY 预览
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作者 郑伟珊 陈艳萍 《数学物理学报:B辑英文版》 SCIE CSCD 2019年第2期607-617,共11页
In this article, we study the Volterra integral equations with two kinds of delay that are proportional delay and nonproportional delay. We mainly use Chebyshev spectral collocation method to analyze them. First, we u... In this article, we study the Volterra integral equations with two kinds of delay that are proportional delay and nonproportional delay. We mainly use Chebyshev spectral collocation method to analyze them. First, we use variable transformation to transform the equation into an new equation which is defined in [-1,1]. Then, with the help of Gronwall inequality and some other lemmas, we provide a rigorous error analysis for the proposed method, which shows that the numerical error decay exponentially in L^∞ and Lω^2c-norm. In the end, we give numerical test to confirm the conclusion. 展开更多
关键词 VOLTERRA integral equation proportional DELAY nonproportional DELAY linear transformation CHEBYSHEV spectral-collocation method GRONWALL INEQUALITY
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Sharp L^p decay of oscillatory integral operators with certain homogeneous polynomial phases in several variables
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作者 Shaozhen Xu Dunyan Yan 《中国科学:数学英文版》 SCIE CSCD 2019年第4期649-662,共14页
In this paper, we obtain the L^p decay of oscillatory integral operators Tλ with certain homogeneous polynomial phase functions of degree d in(n + n)-dimensions;we require that d > 2 n. If d/(d-n)< p < d/n,t... In this paper, we obtain the L^p decay of oscillatory integral operators Tλ with certain homogeneous polynomial phase functions of degree d in(n + n)-dimensions;we require that d > 2 n. If d/(d-n)< p < d/n,the decay is sharp and the decay rate is related to the Newton distance. For p = d/n or d/(d-n), we obtain the almost sharp decay, where "almost" means that the decay contains a log(λ) term. For otherwise, the L^p decay of Tλ is also obtained but not sharp. Finally, we provide a counterexample to show that d/(d-n) p d/n is not necessary to guarantee the sharp decay. 展开更多
关键词 OSCILLATORY integral operators SHARP L^p DECAY several variables NEWTON distance
基于啮合线积分的直齿轮副啮合效率计算方法 预览
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作者 王成 《陕西理工大学学报:自然科学版》 2019年第3期17-21,共5页
在沿啮合线积分法的应用中得到的均是一对轮齿从啮入到啮出的啮合效率,而非一对齿轮传动的啮合效率,不符合齿轮连续传动的实际情况。基于上述问题,从一对齿轮副连续传动的过程入手,首先给出了单对齿轮副瞬时接触点啮合效率的计算公式,... 在沿啮合线积分法的应用中得到的均是一对轮齿从啮入到啮出的啮合效率,而非一对齿轮传动的啮合效率,不符合齿轮连续传动的实际情况。基于上述问题,从一对齿轮副连续传动的过程入手,首先给出了单对齿轮副瞬时接触点啮合效率的计算公式,然后计算了齿轮连续传动过程中各段啮合线的长度,推导出了每段的啮合效率。在此基础上,根据齿轮连续传动的实际情况,计算得到齿轮副的平均啮合效率。最后,分析了齿轮设计参数与齿轮啮合效率之间的关系,提出了提高齿轮啮合效率下齿轮参数的设计原则。 展开更多
关键词 直齿轮 啮合效率 啮合线 积分
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Spectral method for multidimensional Volterra integral equation with regular kernel
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作者 Yunxia WEI Yanping CHEN +1 位作者 Xiulian SHI Yuanyuan ZHANG 《中国数学前沿:英文版》 SCIE CSCD 2019年第2期435-448,共14页
This paper is concerned with obtaining an approximate solution for a linear multidimensional Volterra integral equation with a regular kernel. We choose the Gauss points associated with the multidimensional Jacobi wei... This paper is concerned with obtaining an approximate solution for a linear multidimensional Volterra integral equation with a regular kernel. We choose the Gauss points associated with the multidimensional Jacobi weight function ω(x)=∏di=1(1-xi)^α(1+xi)^β,-1<α,β<1/d-1/2 (d denotes the space dimensions) as the collocation points. We demonstrate that the errors of approxima te solution decay exponentially. Numerical results are presen ted to demonstrate the effectiveness of the Jacobi spectral collocation method. 展开更多
关键词 MULTIDIMENSIONAL Volterra integral equation JACOBI COLLOCATION discretization: MULTIDIMENSIONAL Gauss QUADRATURE formula
Multiple Positive Solutions to Singular Fractional Differential System with Riemann-Stieltjes Integral Boundary Condition 预览
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作者 Zhang Hai-yan Li Yao-hong 《数学研究通讯:英文版》 CSCD 2019年第3期208-218,共11页
In this paper, we study a class of singular fractional differential system with Riemann-Stieltjes integral boundary condition by constructing a new cone and using Leggett-Williams fixed point theorem. The existence of... In this paper, we study a class of singular fractional differential system with Riemann-Stieltjes integral boundary condition by constructing a new cone and using Leggett-Williams fixed point theorem. The existence of multiple positive solutions is obtained. An example is presented to illustrate our main results. 展开更多
关键词 FRACTIONAL differential equation positive solution INTEGRAL boundary condition fixed point THEOREM
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