Hopfield neural network and its applications on image edge detection

A method of image edge detection using the Hopfield neural network (HNN) is proposed in this paper.The image edge parameters are introduced in detail, and the energy function of HNN is given based on the edge parameters. Tests on the image edge detection show that images detected by the proposed method have good edge closeness and true edge, at the same time it has good anti-noise performance. The image edge detection using HNN is better than that obtained by some other edge detection operators.     

边角效应对双辉离子渗金属加工的影响

在采用双辉光放电实施的离子渗金属加工中，存在强烈的边角效应。从等离子体性能入手，实验研究了这种边角效应，并分析了该种边角效应产生的原因，讨论了它对双辉光放电离子渗金属加工的影响。     

基于多特征和FCM的图像边缘检测方法

提出了一种新的基于多特征和FCM的边缘检测算法.该方法根据边缘点附近灰度分布特点构造了多个反映边缘特性的特征分量,并利用输入图像提取该组特征分量,组成一个反映图像边缘特征的数据集.用FCM聚类算法将该数据集分为两类,即边缘点数据和非边缘点数据,实现边缘检测.该方法无需确定阈值,对弱边缘检测较敏感,在特征的选取上充分考虑了边缘和噪声的本质区别,因而具有优异的抗噪性能.     

Free vibrations of a plate with an inner support

The title problem is tackled by using a simple polynomial co-ordinate function and the Rayleigh-Schmidt method. It is assumed that the inner support is parallel to the free edge. When the support coincides with the free edge the frequency equation degenerates properly into the case of a simply supported edge. Numerical results are presented for the situation where two opposite edges are simply supported and the edge parallel to the free edge is either clamped or simply supported.     

Edge stacking dislocations in two-dimensional bilayers with a small lattice mismatch

Incomplete stacking dislocations are predicted to form at edges of the shorter upper layer in two-dimensional hexagonal bilayers upon stretching the longer bottom layer. A concept of the edge Burgers vector is introduced to describe such dislocations by analogy with the Burgers vector of standard bulk dislocations. Analytical solutions for the structure and energy of edge stacking dislocations in bilayer graphene are obtained depending on the magnitude of elongation and angles between the edge Burgers vector, direction of elongation and edge. The barrier for penetration of stacking dislocations inside the bilayer is estimated. The possibilities to measure the barrier to relative motion of graphene layers and strain of graphene on a substrate by observation of edge stacking dislocations are discussed.     

Edge absorption and circular photogalvanic effect in 2D topological insulator edges

The electron absorption on the edge states and the edge photocurrent of a 2D topological insulator (TI) are studied. We consider the optical transitions within linear edge branches of the energy spectrum. The interaction with impurities is taken into account. The circular polarization is found to produce the edge photocurrent, the direction of which is determined by light polarization and edge orientation.     

Effect of isolated defects and defect pairs on the spectrum of the edge luminescence of solids

Expressions for the intensities of bands in the edge luminescence spectrum of a solid containing both isolated defects (shallow acceptors and donors) and defect pairs are given. Conditions under which the contribution of defects to the edge luminescence bands is negligible or dominant are found. Analysis of the edge luminescence spectrum of semi-insulating GaAs shows that situations in which the intensities of the edge luminescence bands are determined by the states of isolated shallow acceptors and donors and donor-acceptor pairs are quite probable.     

Propagation of partially coherent beams carrying an edge dislocation through atmospheric turbulence along a slant path

This paper derives the explicit expressions for the average intensity, beam width and angular spread of Gaussian Schell-model (GSM) beams with edge dislocation propagating through atmospheric turbulence along a slant path. The propagation of GSM beams with edge dislocation through horizontal atmospheric turbulence can be treated as a special case through a slant one. The propagation properties of GSM beams with edge dislocation through slant atmospheric turbulence are studied, where the influence of edge dislocation parameters including the slope p and off-axis distance d on the spreading of GSM beams with edge dislocation in atmospheric turbulence is stressed. It shows that the spreading of the intensity profile of GSM beams with edge dislocation along a slant path is smaller than that along a horizontal path in the long-distance atmospheric propagation. The larger the slope vert pvert and the smaller the off-axis distance vert dvert are, the less the beam-width spreading and angular spread of GSM beams with edge dislocation are affected by turbulence. The GSM beams with edge dislocation is less affected by turbulence than that of GSM beams without edge dislocation. The results are illustrated numerically and their validity is interpreted physically.     

Circular photogalvanic effect caused by the transitions between edge and 2D states in a 2D topological insulator

The electron absorption and the edge photocurrent of a 2D topological insulator are studied for transitions between edge states to 2D states. The circular polarized light is found to produce the edge photocurrent, the direction of which is determined by light polarization and edge orientation. It is shown that the edge-state current is found to exceed the 2D current owing to the topological protection of the edge states.     

一种多尺度边缘测度融合加权HD算法

一般的边缘加权Hausdorff算法,由于单尺度边缘检测算子本身对噪音敏感,会造成真实和虚假边缘显著性差异小,从而加权后对噪音鲁棒性改善有限.为此,提出了一种基于多尺度边缘测度融合加权的Hausdorff景象匹配算法.对图像提取多尺度边缘测度后,引入证据推理理论,提出一种双向指数基本置信指派构造方法,并构造出多尺度边缘测度的基本置信指派函数,然后采用冲突再分配DSmT组合规则进行融合.为了进一步区别真实边缘与高频噪音,对加权Hausdorff公式进行了一些改进,给出了更为有效利用融和后边缘测度的加权Hausdorff公式.对可见光和SAR景象的匹配实验证明:本文算法所提取边缘在抑制噪音的同时保留了大量景象细节信息,并通过横向对比验证本文算法提高了噪音鲁棒性.     

晶体缺陷规范场中的刃位错

本文用位错连续分布方法表出了刃位错所产生的应变和应力场,得到了刃位错芯区内、外的应力场,位错芯区的无限小位错分布用缺陷规范场表出,并在一定规范条件下求解了位错规范场,在刃位错芯区外,其应力场与Volterra位错的应力场完全一样,而在芯区内,当r趋于零,刃位错的应力场为有限,消除了应力的奇异性。 关键词：     

一种改进的Zernike正交矩亚像素边缘检测算法

在分析Ghosal提出的基于Zernike正交矩亚像素边缘检测算法的基础上,对Ghosal算法进行了改进。指出了Ghosal算法的两点不足,即没有考虑模板效应和没有考虑边缘梯度方向上的一阶导数模型。针对这种不足提出了改进方法。改进后的算法在计算边缘亚像素坐标时更准确,同时还具有细化边缘的能力,使边缘定位更精确。     

Binaural coherence edge pitch

The binaural coherence edge pitch (BICEP) is a dichotic broadband noise pitch effect similar to the binaural edge pitch (BEP). The BICEP stimulus is made by summing spectrally dense sine wave components with random phases. The interaural phase angle is a constant (0 or pi) for components with frequencies below (or above) a chosen edge frequency, and it is a random variable for the remaining components. The chosen edge frequency is a coherence edge because the noises to the two ears are mutually coherent within any band of frequencies on one side of the edge and they are mutually incoherent in any band on the other side. Pitch-matching experiments show that the BICEP exists for coherence edge frequencies between about 300 and 1000 Hz. It is matched by a pure-tone frequency that differs from the edge frequency by 5% to 10%. The matching frequency lies on the incoherent side of the edge, an important result that is consistent with the way that the equalization-cancellation model has been applied to binaural pitch effects, especially the BEP. The results of BICEP experiments depend upon whether the coherent components are presented in 0 or pi interaural phase for some listeners but not for all. The BICEP persists if the noise to one of the ears is delayed, but it becomes weaker and less well matched as the delay increases beyond 2 ms. The BICEP does not depend on whether the component amplitudes are all created equal or are given a Rayleigh distribution. Some reliable pitch sensation exists even when the component amplitudes are entirely independent in the two ears, so long as the phase coherence conditions of the BICEP stimulus are maintained. The existence of the BICEP is a challenge for current models of dichotic pitch because none of them predicts all its features.     

前缘形状对钝三角翼边界层稳定性及转捩的影响

选择典型高速流动条件,基于线性稳定性理论研究了不同前缘几何特征对典型大后掠角平板钝三角翼外形高速边界层流动稳定性及转捩的影响.研究表明,椭前缘(截面为椭圆)形状的变化仅影响前缘附近的流场特征和边界层流动稳定性;前缘截面长短轴比(形状因子)变大,前缘形状变尖,则横流速度变大,扰动波增长率变大;对于横流模态和第1模态,不同...     

Vibrational properties and Raman spectra of different edge graphene nanoribbons,studied by first-principles calculations

The vibrational properties and Raman spectra of graphene nanoribbons with six different edges have been studied by using the first-principles calculations. It is found that edge reconstruction leads to the emergence of localized vibrational modes and new topological defect modes, making the different edges identified by polarized Raman spectra. The radial breathing-like modes are found to be independent of the edge structures, while the G-band-related modes are affected by different edge structures. Our results suggest that the polarized Raman spectrum could be a powerful experimental tool for distinguishing the GNRs with different edge structures due to their different vibrational properties.     

Sound pulse scattering from an edge of thick elastic plates:experimental and numerical investigations

I.IntroductionItisdifficulttoanaIysesoundscattcringfromanedgeofathickpIatetheoretica11y.Inmostprevious.ork['-'],thecdgcdifTractionsofidca1ha1fp1aneswereconsidered,i.e.theplanesarepcrfcct1yhardorpcrfcctlysoftoroncsurfacehardandonesurfacesoftandtheirthicknessisneg1cctcd,thccorrespondingthporicsarcquitecomp1ctc.Inthisstudy,thecdgcscattcringfromthickelasticplatesinwatcrisinvestigated.Theex'perimentalrcsultsarccxamincdphysica1lybythcp1atethcoryandcomparcdquantitative1ywithca1culationsfromanumeric…     

Hydrogen passivation tunes edge magnetism in the ZMoS2NR with a sulfur vacancy

We performed density functional theory study on electronic structure, magnetic properties and stability of zigzag MoS₂ nanoribbons with a S vacancy (ZMoS₂NRs-V_S) and considered their different edge passivation. The ZMoS₂NR-V_S systems are magnetic metals with ferromagnetic (FM) edge states. The magnetic moments are greatly influenced by the site of S vacancy and edge passivation because the vacancy and edge states significantly change the structure of the systems. Importantly, we can achieve distinct FM states such as both edge FM and single edge FM states in the ZMoS₂NRs-V_S by tuning edge passivated pattern. Additionally, edge passivation can not only tune the magnetism of the ZMoS₂NRs-V_S but also enhance their stability by eliminating dangling bonds. These interesting findings on the ZMoS₂NRs may open the possibility of their application in nanodevices and spintronics.     

Acoustic diffraction by deformed edges of finite length: theory and experiment

The acoustic diffraction by deformed edges of finite length is described analytically and in the frequency domain through use of an approximate line-integral formulation. The formulation is based on the diffraction per unit length of an infinitely long straight edge, which inherently limits the accuracy of the approach. The line integral is written in terms of the diffraction by a generalized edge, in that the "edge" can be a single edge or multiple closely spaced edges. Predictions based on an exact solution to the impenetrable infinite knife edge are used to estimate diffraction by the edge of a thin disk and compared with calculations based on the T-matrix approach. Predictions are then made for the more complex geometry involving an impenetrable thick disk. These latter predictions are based on an approximate formula for double-edge diffraction [Chu et al., J. Acoust. Soc. Am. 122, 3177 (2007)] and are compared with laboratory data involving individual elastic (aluminum) disks spanning a range of diameters and submerged in water. The results of this study show this approximate line-integral approach to be versatile and applicable over a range of conditions.     

椭圆目标的亚像素边缘定位方法研究

分析和比较了三种常见的基于矩的亚像素边缘定位方法,得出三种方法获取的边缘角度以及OFMM法与ZOM法获取的亚像素边缘相同的结论。提出了一种针对椭圆目标的亚像素边缘定位方法。在ROI提取和SOBEL算子初步检测边缘的基础上,利用初步获取的椭圆目标的几何信息,将参与计算的模板个数减少至一个,从而大大减少了运算时间,提高了算法的运算速度。同时实验结果表明,与其他基于矩的亚像素边缘定位方法相比,新方法不仅有更高的运算速度,而且精度和抗噪性能都有很大地提高。