Magnetoelectroelastic fields in rotating multiferroic composite cylindrical structures

An analytical solution is obtained for a rotating multiferroic composite hollow cylinder made of radially polarized piezoelectric and piezomagnetic materials. Both the number of layers and the stacking sequence of the composite cylinder can be arbitrary. General mechanical, electric and magnetic boundary conditions can be applied at both the inner and outer cylindrical surfaces. The state space method is employed so that only a 2×2 matrix is involved in the whole solving procedure. In the numerical experiments, the distributions of elastic, electric as well as magnetic fields in an internally pressurized rotating BaTiO3/CoFe2O4 composite hollow cylinder subjected to different boundary conditions are presented graphically. The results clearly show that the stress fields in a multiferroic composite cylinder are controllable.     

Numerical computations of the flow in a finite diverging channel

The flow in a finite diverging channel opening into a large space and resembling the experimental prototype of Putkaradze and Vorobieff （2006） was numerically investigated. The effects of the Reynolds number, initial condition, intersection angle, length of the wedge edges, and the outer boundary condition were examined. The numerical results showed that the flow in the wedge undergoes a change from symmetrical flow to unsymmetrical flow with a weak backflow, then a vortical （circulation） flow and finally an unsteady jet flow as the Reynolds number is increased for an intersection angle of 32° and a wedge edge of length 30 times the width of the inlet slit. For the unsteady flow, the jet attached to one side of the wedge constantly loses stability and rolls up into a mushroom-shaped vortex-pair near the outlet of the wedge. As the intersection angle is increased to 50°, a stable jet flow is observed as a new regime between the vortex and unsteady regimes. Both the intersection angle and the wedge length have negative effects on the stability of the flow, although the effect of the wedge length on the critical Reynolds number for the symmetry-breaking instability is not pronounced. The outer boundary condition was found not to affect the flow patterns inside the wedge significantly. At a certain Re regime above the onset of symmetry-breaking instability, the flows evolve into steady state very slowly except for the initial stage in the case of decreasing flow flux. Two different solutions can be observed within the normal observation time for the experiment, providing a possible explanation for the hysteresis phenomenon in the experiment.     

A state space solution for the bending problem of thick laminated piezoelectric open cylindrical shells

Based on the theories of three-dimensional elasticity and piezoelectricity, and by assuming appropriate boundary functions, we established a state equation of piezoelectric cylindrical shells. By using the transfer matrix method, we presented an analytical solution that satisfies all the arbitrary boundary conditions at boundary edges, as well as on upper and bottom surfaces. Our solution takes into account all the independent elastic and piezoelectric constants for a piezoelectric orthotropy, and satisfies continuity conditions between plies of the laminates. The principle of the present method and corresponding results can be widely used in many engineering fields and be applied to assess the effectiveness of various approximate and numerical models.     

Science Letters：Visual odometry for road vehicles —— feasibility analysis

Estimating the global position of a road vehicle without using GPS is a challenge that many scientists look forward to solving in the near future. Normally, inertial and odometry sensors are used to complement GPS measures in an attempt to provide a means for maintaining vehicle odometry during GPS outage. Nonetheless, recent experiments have demonstrated that computer vision can also be used as a valuable source to provide what can be denoted as visual odometry. For this purpose, vehicle motion can be estimated using a non-linear, photogrametric approach based on RAndom SAmple Consensus (RANSAC). The results prove that the detection and selection of relevant feature points is a crucial factor in the global performance of the visual odometry algorithm. The key issues for further improvement are discussed in this letter.     

APPENDIX A： ALTERNATIVE WAY OF OBTAINING THE LEAST-SQUARES PROBLEM

It is worth to mention that Eq.（19） can be found alternatively first by describing the boundary conditions at each of the sampling points to obtain a set of linear equations with respect to the modal coefficients Then, determining the number of sampling points in order that the number of linear equations be twice the number of unknowns     

Analytical solution for functionally graded anisotropic cantilever beam under thermal and uniformly distributed load

The bending problem of a functionally graded anisotropic cantilever beam subjected to thermal and uniformly dis-tributed load is investigated,with material parameters being arbitrary functions of the thickness coordinate. The heat conduction problem is treated as a 1D problem through the thickness. Based on the elementary formulations for plane stress problem,the stress function is assumed to be in the form of polynomial of the longitudinal coordinate variable,from which the stresses can be derived. The stress function is then determined completely with the compatibility equation and boundary conditions. A practical example is presented to show the application of the method.     

《德伯家的苔丝》中苔丝悲剧的浅析(英文)

Tess of the D’Urbervilles is one of Thomas Hardy’s most famous novels.In this novel,the heroine,Tess,is figured with intelligence as well as beauty.She possesses all of praise-worthy qualities of labors:pure,industrious,responsible,brave and fortitudinous.And Tess has long been regarded as the most exceptional woman character in literary history.However,the life of this pure woman is tragic.This paper mainly analyzes the external reasons and internal reasons that results in the tragedy which she is changing from a girl with beauty and pureness to a young lady with muddling along and giving herself up,at last she walks to the execution ground.From all the points mentioned above,we can better and deeply understand Tess and her tragedy,and we can know the root of the Tess’s tragedy is the evil capitalist society at that time.     

On Translation of Passiveness from English to Chinese

Translation is an art,a bilingual art.Like painting,translation enables us to reproduce the fine thought of somebody,not in colors,but in words,in words of a different language.It is no easy job,not so easy as it is supposed.Many can speak and write it well,but they can not translate well.This paper is mainly discussing the method of translating English to Chinese.Also analyses and classifies the translation of the passive voice from English to Chinese,and also points several language points should be considered in translating.     

Relation among C-curve characterization diagrams

As three control points are fixed and the fourth control point varies, the planar cubic C-curve may take on a loop, a cusp, or zero to two inflection points, depending on the position of the moving point. The plane can, therefore, be partitioned into regions labelled according to the characterization of the curve when the fourth point is in each region. This partitioned plane is called a "characterization diagram". By moving one of the control points but fixing the rest, one can induce different characterization diagrams. In this paper, we investigate the relation among all different characterization diagrams of cubic C-curves based on the singularity conditions proposed by Yang and Wang (2004). We conclude that, no matter what the C-curve type is or which control point varies, the characterization diagrams can be obtained by cutting a common 3D characterization space with a corresponding plane.     

A new method in highway route design: joining circular arcs by a single C-Bézier curve with shape parameter

We constructed a single C-Bezier curve with a shape parameter for G^2 joining two circular arcs. It was shown that an S-shaped transition curve, which is able to manage a broader scope about two circle radii than the Bezier curves, has no curvature extrema, while a C-shaped transition curve has a single curvature extremum. Regarding the two kinds of curves, specific algorithms were presented in detail, strict mathematical proofs were given, and the effectiveness of the method was shown by examples This method has the following three advantages： （1） the pattern is unified; （2） the parameter able to adjust the shape of the transition curve is available; （3） the transition curve is only a single segment, and the algorithm can be formulated as a low order equation to be solved for its positive root. These advantages make the method simple and easy to implement.     

利用Coons曲面构造曲面上的G1插值曲线

利用双三次Coons曲面, 给出了一种对隐式或参数曲面上任意点序列及切方向给定时的G1连续插值方法.首先构造G1连续的组合Coons曲面, 其次求该组合曲面片与已知曲面的交线. 插值曲线是组合Coons曲面片与给定曲面的交线. 由于引入了若干控制参数, 可对曲线进行交互修改使得其最终的形状更好地满足我们的要求. 实验证明该方法简单可行, 适用于计算机辅助设计、计算机图形学等领域.     

基于MatLab整体线性分形插值的研究

本文分析了整体线性分形插值原理，利用曲线上的有限个插值点，选取适当的垂直比例因子，可以近似地构造出原曲线，在此逼近计算的过程中，给出了一种易实现的分形插值误差计算方法，并基于MatLab说明了整体线性分形插值的实现过程。同时提出了粒子群优化算法寻最优垂直比例因子的可能性。最后讨论了分形插值中的一些问题及发展状况。     

Subdivision surface modeling system based on arbitrary topological curves network and combined subdivision

Arbitrary topological curve network has no restriction in topology structure, so it has more powerful representing ability in defining complex surfaces. A complex surface modeling system is presented based on arbitrary topological curve network and the improved combined subdivision method, its functions including creating and editing curve network, and generating and modifying curve network’s interpolated surface. This modeling system can be used to the process of products’ concept design, and its applications is also significant to the development of subdivision method.     

二阶曲线射影分类方法探讨

判别二阶曲线射影分类方法有自极三角形法、选点法、主子式法、配方法和初等变换法。五种方法可把任给一条二阶曲线的方程化为标准形式,再判断它的类型。它们各有所长,可根据实际要求选择使用。     

正三角形三角点的分布

本文利用限制圆和限制区域,给出了费尔马点为三角点的判断条件,同时得到了特殊的正三角形的三角点的分布情况     

Intersections of two offset parametric surfaces based on topology analysis

INTRODUCTIONTheOSSI(OffsetSurface/SurfaceIntersection)problemisasub-problemofgeneralSSI.AlthoughtheOSSIproblemcanberesolvedbyapplyinggeneralSSIalgorithm,itiscomputationallyexpensiveandexhaustive.Inrecentdecades,effortshavebeenfocusedoncomputingSSIexactly,efficiently,androbustlyinageneralsetting(Abdel-MalekandYeh,1997;Changetal.,1994;BurkeandSabharwal,1996;Mullenheim,1991).Thesetechniquescanbeclassifiedmainlyintofivecategories:algebraic,latticeevaluation,marching(tracing)method,…     

Intersections of two offset parametric surfaces based on topology analysis

Conventional methods for solving intersections between two offset parametric surfaces often include iteratively using computationally expensive SSI (surface/surface intersections) algorithm. In addition, these methods ignore the relations between the intersection curves of parametric surfaces with different offset distances. The algorithm presented in this paper, makes full use of the topological relations between different intersection loops and calculates intersection loops with the help of previously calculated intersection loops. It first pre-processes two parametric surfaces to obtain the characteristic points, called topology transition points (TTPs), which can help in the subsequent finding of the topologies of the intersection curves. Then these points are categorized into several distinct groups, and we can determine the calculation strategy for searching initial points by analyzing the properties of these TTPs on the surfaces. Hence, all intersection curves can be marched from initial points by the tracing algorithm. The proposed algorithm could calculate intersection curves robustly and effectively, and has been tested to be capable of overcoming the degenerate conditions such as loop and singularities leaking that occur frequently in conventional algorithms. Project supported by the National Research Foundation for the Doctoral Program (No. 2000033554) of Higher Education of China and the Natural Science Foundation of Zhejiang Province, China (No. 6001107)     

Using texture synthesis in fractal pattern design

INTRODUCTIONIn the last two decades, research on fractal ge-ometry has received much attention for its theoretical significance and practical applications. Pattern design based on fractal geometry is an important application area of fractal techniques in the textile industry (Wang, 2003). Computer aided pattern design involves the de-sign of textures and colors in the pattern. The source of textures is rich. All kinds of objects and scenery including man-made abstract objects can be used…     

分形与计算机模拟

给出了分形的有关概念，以Koch分形工线为例介绍了用计算机模拟分形图形的方法，给出了画Koch分形的函数代码。     

基于布尔运算的巷道精准建模研究及应用

为了改善巷道三维建模算法中特殊交岔点不能相互贯通的缺点,研究基于布尔运算的巷道交岔点建模算法,以实现巷道各类交岔点的相互贯通。根据实测导线数据、断面参数及巷道属性信息,采用六元组统一方法表示断面形状,实现巷道交岔点及各断面形状的连接。实验结果表明,基于布尔运算算法的垂直巷道交岔点建模算法贯通率达到100%。该算法不仅实现了巷道交岔点的相互贯通,而且能有效修正巷道设计中存在的误差,提高巷道三维模型精度。