圆和椭圆边缘检测的快速方法

利用图形边界对偶点及其平移、缩放和旋转的不变性质 ,结合 Hough变换 ,建立圆和椭圆边缘快速检测的算法 ,并且弥补了文 [1 ]和 [3]中关于圆和椭圆计算公式的缺陷 .实验例子表明本文方法不仅简便、计算速度快、对噪声不敏感 ,而且可以灵活应用解决一些较难的检测问题     

On the representation and implicit integration of general isotropic elastoplasticity based on a set of mutually orthogonal unit basis tensors

A simple and compact representation framework and the corresponding efficient numerical integration algorithm are developed for constitutive equations of isotropic elastoplasticity. Central to this work is the utilization of a set of mutually orthogonal unit tensor bases and the corresponding invariants. The set of bases can be regarded equivalently as a local cylindrical coordinate system in the three‐dimensional coaxial tensor subspace, namely, the principal space. The base tensors are given in the global coordinate system. Similar to the principal space approach, the proposed method reduces the problem dimension from six to three. In contrast to the conventional approach, the transformation procedure between the principal space and the general space is avoided and explicit computation of the principal axes is bypassed. With the proposed technique, the matrices, which need to be inverted during iteration, take a simple form for the great majority of constitutive equations in use. The tangent operator consistent with the proposed algorithm can be decomposed into the direct sum of two linear maps over the coaxial tensor subspace and the subspace orthogonal to it. Consequently, its closed form is derived in an extremely simple manner. Finally, numerical examples demonstrate the high quality performances of the proposed scheme. Copyright © 2014 John Wiley & Sons, Ltd.     

液阻悬置惯性通道阻尼特性的实验与计算分析

以一轿车动力总成惯性通道型液阻悬置为研究对象,讨论了线性与非线性集总参数模型和模型中物理参数的特点及应用范围;应用流体力学有限元分析的方法,计算得到了惯性通道两端压力差与其中液体流动流量的关系,设计并制作了实验台,对计算结果进行了验证.利用惯性通道中液体流动的动量方程和惯性通道两端的压力差与其流量的关系,采用最小二乘方法,得到了惯性通道中液体流动的阻尼参数.该方法得到的阻尼参数,在较大激振频率和激振振幅范围内反应了惯性通道的阻尼特性.利用非线性的集总参数模型和本文方法得到的惯性通道阻尼特性参数,对一液阻悬置的动态特性进行了计算分析,计算结果和实验结果具有较好的一致性.     

朝鲜半岛构造系统地质环境演化及动力学机制的地球卫星遥感影像解译研究

采用将东亚地区综合资料分析成果与地球卫星遥感影像解译相结合的方法,深入研究了全球构造域中典型的构造地段朝鲜地块。详细识别出朝鲜半岛地区的基本构造形式,其基本类型主要有环形构造（及辐射构造）、追踪构造、共轭构造、菱形构造、多米诺构造等;对其构造地质环境演化过程及地球动力学机制进行了宏观阐述,晚古生代之前朝鲜半岛是由中国东部三个不同板块（华北板块;扬子板块、华南板块）贴拼焊接而成,中生代隆起成陆以后遭受了三期构造运动的影响（松林运动、大宝运动、佛国寺运动）,新生代发生了玉岭运动。朝鲜地块基本构造形式的形成受中国边缘海盆地与日本海盆地的侧向水平运动的影响,其构造主应力轨迹线方向为北东-南西向延伸,近代主应力轨迹线方向表现为北西西-南东东向展布,对其引起的现代地质作用及环境效应得到有关部门的充分注意。     

On the numerical solution of the Dirichlet initial boundary-value problem for the heat equation in the case of a torus

The initial-boundary-value problem for the heat equation in the case of a toroidal surface with Dirichlet boundary conditions is considered. This problem is reduced to a sequence of elleptic boundary-value problems by a Laguerre transformation. The special integral representation leads to boundary-integral equations of the first kind and the toroidal surface gives one-dimensional integral equations with a logarithmic singularity. The numerical solution is realized by a trigonometric quadrature method in cases of open or closed smooth boundaries. The results of some numerical experiments are presented.     

On the continuation of the limit distributions of the extreme and central terms of a sample

We consider the situation where the distribution functions (d.f.'s) of the suitably normalized extreme and central order statistics on an interval [c,d] converge to arbitrary nondecreasing functions. The continuation of these convergences (weak) on the whole real line to the extreme and central value distributions is then proved under general conditions.     

Features of the Construction of a Checking Scheme for Instruments for Measuring DC Voltage and Electromotive Force

The features of the transfer of the dimensions of the volt from a new-generation primary standard to working measuring instruments in the new State checking scheme for instruments for measuring dc voltage and electromotive force are considered. __________ Translated from Izmeritel'naya Tekhnika, No. 8, pp. 48–49, August, 2005.     

Side-sensitive modified group runs charts with and without measurement errors for monitoring the coefficient of variation

The coefficient of variation (CV) is used in process monitoring when the process mean and standard deviation are proportional to each other. In this work, a side-sensitive modified group runs CV (SSMGR CV) chart is proposed for monitoring the process CV. The run length performance of the SSMGR CV chart is compared to those of the existing CV charts in terms of the average and standard deviation of the run length criteria. The SSMGR CV chart is found to outperform the existing CV charts. In addition, the run length performance of the SSMGR CV chart is also evaluated in the presence of measurement errors, as these errors are not only unavoidable in practice but they also affect the sensitivity of a control chart in detecting an out-of-control situation. The results obtained show that the accuracy and precision errors affect the performance of the SSMGR CV chart in detecting an out-of-control situation.     

On solvability of a boundary integral equation of the first kind for Dirichlet boundary value problems in plane elasticity

The solution of a Dirichlet boundary value problem of plane isotropic elasticity by the boundary integral equation (BIE) of the first kind obtained from the Somigliana identity is considered. The logarithmic function appearing in the integral kernel leads to the possibility of this operator being non-invertible, the solution of the BIE either being non-unique or not existing. Such a situation occurs if the size of the boundary coincides with the so-called critical (or degenerate) scale for a certain form of the fundamental solution used. Techniques for the evaluation of these critical scales and for the removal of the non-uniqueness appearing in the problems with critical scales solved by the BIE of the first kind are proposed and analysed, and some recommendations for BEM code programmers based on the analysis presented are given.     

Research and Application for the Regularity of Distribution about Curvature Radius and Curvature Center of the Linkage Point Track in a Link Mechanism

It is illustrated that there exists an inflection circle on the linkage rigid body by the principle of relative motion. Confirmed methods of the inflection circle, curvature radius and curvature center of the point track on the linkage rigid body are given in the case of the different contact type of move instantaneous center line and static instantaneous center line. The regularity of distribution of curvature radius and curvature center of the point track is researched. The identification methods called determination parameters and auxiliary vertical line of the diameter and direction of the inflection circle in the four bar mechanism are pointed out. A design method of the crane hoisting mechanism is discussed in the end of this paper.     

The selection of international standards for the thermodynamic properties of HFC-134a and HCFC-123

The objectives and activities of the International Energy Agency-Annex 18 are summarized. One of the goals of the Annex was to determine the formulations that best represent the thermodynamic properties of HFC-134a and HCFC-123. The formulations selected were those which accurately represented the experimental data and simultaneously exhibited thermodynamic consistency. Methods of comparison include analysis of the experimental data, statistical comparisons of values calculated from the property formulations to experimental values, and graphical analyses of the thermodynamic surface. The analytical methods used are summarized in this paper. The equations of state reviewed in these comparisons represented the most accurate formulations available in December 1992. Four equations of state were reviewed for HFC-I34a and three equations of state were considered for HCFC-123. These equations represented the work of independent researchers in Germany, Japan, and the United States. The formulations selected as international standards are presented.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

A method and instrument for measuring the thermal properties of samples of a regenerative product in a matrix when they are heated by a constant heat flux

A mathematical model of a method of measuring the thermal properties of new regenerative products is developed. The construction of a measuring instrument is proposed. Experimental data on the thermal conductivity and volume heat capacity of regenerative products in a matrix are obtained. Translated from Izmeritel’naya Tekhnika, No. 5, pp. 49–53, May, 2009.     

基于百年办学史探工艺美术人才培养模式改革

正值湖北美术学院办学100周年之际,亦是工艺美术专业恢复招生的第6年。现今的工艺美术专业已经有别于20世纪50年代的工艺美术,但百年办学历史上,从图案工艺到工艺美术,再到艺术设计,至今天的工艺美术专业,虽几经波折,但学脉始终延续。文章通过对湖北美术学院各阶段办学史中的工艺美术相关人才培养模式的梳理和分析,立足时代发展,对该校工艺美术专业改革提出创新性建议。     

Use of a modified Gurson model approach for the simulation of ductile fracture by growth and coalescence of microvoids under low, medium and high stress triaxiality loadings

In the paper the modified Gurson model is developed for the simulation of damage growth and ductile fracture under low, medium and high stress triaxiality loadings. A new coalescence criterion is introduced based on a simple assumption that singular value of the effective stress triggers the coalescence of microvoids in materials. According to the introduced approach the void coalescence described by means of the modified Gurson model is not only determined by the so-called critical, constant void volume fraction but also by the stress triaxiality ratio. Computational simulations have been carried out for Al 2024–T351 aluminum specimens. In order to find some improvements of micromechanical damage models, two different approaches have been compared for modeling the shear driven microvoid coalescence under low stress triaxiality loadings.