High-field magnetic phase diagram of CsCoCl3 revised

A fine structure of high-field magnetization curves of CsCoCl₃ and related compounds is discussed. It is shown that a precursor of a high-field phase transition originates from nucleation of an intermediate high-field ferrimagnetic (IFM) phase. Since the IFM state is degenerate its growth starting from few nucleation centers gives rise to domain walls formation. Their creep also makes a contribution to the magnetization dynamics similar to slow relaxation in Ca₃Co₂O₆. An experimental verification of the model is proposed.     

硅基孔状光子晶体高选择性滤波器设计

通过平面波展开法研究了三角孔状光子晶体晶格的能带结构,并考虑了该过程的辐射损耗.用时域有限差分的方法模拟计算了对应六边形环行腔结构的光谱透射特性,得出优化的晶格周期和占空比.在C波段上,优化的结构达到了98.8%的光学选择比和32.9 nm的半高全宽.用光刻和反应离子刻蚀的方法对样片的加工过程进行了尝试并给出加工参量.搭建相应的系统测试了样片的光谱性能,结果表明:实际样片孔状的样片较之柱状样片更为稳定,而基于环行谐振腔的结构在未来有应用于滤波器、波分复用系统、微陀螺等领域.     

Nonorientable triangular embeddings of complete graphs with arbitrarily large looseness

The looseness of a triangular embedding of a complete graph in a closed surface is the minimum integer m such that for every assignment of m colors to the vertices of the embedding (such that all m colors are used) there is a face incident with vertices of three distinct colors. In this paper we show that for every p?3 there is a nonorientable triangular embedding of a complete graph with looseness at least p.     

Mode Matching Analysis of Propagation Characteristics for Dielectric Ridge Guide with Triangular and Trapezoidal Profiles*

Leaky characteristics of dielectric ridge guide with triangular and trapezoidal cross section are analyzed by a method that combines the mode matching procedure with the staircase approximation and multimode microwave network theory. Our emphasis in this paper is on the parametric effects of cross section profile on leakage and propagation properties of the ridge guide. Some numeral results with their explanations are given for practical reference.*Supported by the National Natural Science Foundation of China (No. 60171019) and (No. 60371010)     

Two- and three-spin triangular ising model: Variational approximations

The implications of the known hard-hexagon lattice gas results for the triangular Ising model with both pair and triplet interactions are pointed out. Employing an appropriate generalization of the variational method of Baxter we determine, using the lowest-order approximation, the phase boundaries for this model when the pair interactions are ferromagnetic. Higher approximations are presented for the case of pure triplet interactions and the resulting phase diagrams are in excellent agreement with all exactly known results.     

Free surface wave motions and interactions

This paper investigates the problems involved in the numerical simulation of free surface wave motions and surface wave effects on marine structures. Various approaches that might be taken in meeting these problems are discussed, and their relative advantages and disadvantages are considered. One particular approach combines a Lagrangian formulation of the governing equations, a triangular grid and a finite-difference solution procedure. Since this approach has some distinct advantages in the numerical calculation of fluid flows which include a free surface, it formed the basis for the development of one particular computer code, SPLISH. Sufficient progress has been made with the SPLISH code to demonstrate the attractiveness of numerical calculations for wave flow problems. Recent computational results demonstrate that realistic time-varying local flow fields, pressures and forces on and near structures such as a half-cyclinder on the ocean floor can be determined from numerical calculations for certain conditions. Good agreement is found in comparison of the numerical results from SPLISH, recent linear wave Green's function and fifth-order asymptotic solutions for wave motion over a bottom seated half-cylinder, and an experimental simulation in a wave channel.     

The efficient solution of large-scale linear programming problems—some algorithmic techniques and computational results

First, this paper presents the results of experiments with algorithmic techniques for efficiently solving medium and large scale linear and mixed integer programming problems. The techniques presented here are either original or recent.The solution of a great number of problems has shown that efficient problem solving requires automatic adaptation of algorithmic techniques upon problem characteristics. We show when a given technique should be used for a particular problem.The last part of this paper describes an attempt to provide a powerful mathematical programming language, allowing an easy programming of specific studies on medium-size models such as the recursive use of LP or the build-up of algorithms based on the simplex method.All these features have been implemented in the IBM Mathematical Programming System, MPSX/370, and its feature MIP/370. Extensive numerical results and comparisons on real-life problems are provided and commented upon.Presented at the IXth International Symposium on Mathematical Programming in Budapest (1976).     

Triangular Toeplitz contractions and Cowen sets for analytic polynomials

Let be the collection of lower triangular Toeplitz matrices and let be the collection of lower triangular Toeplitz contractions. We show that is compact and strictly convex, in the spectral norm, with respect to ; that is, is compact, convex and , where and denote the topological boundary with respect to and the set of extreme points, respectively. As an application, we show that the reduced Cowen set for an analytic polynomial is strictly convex; more precisely, if is an analytic polynomial and if , then is strictly convex. This answers a question of C. Cowen for the case of analytic polynomials.

     

Bounding Pyramids and Bounding Cones for Triangular Bézier Surfaces

This paper describes practical approaches on how to construct bounding pyramids and bounding cones for triangular Bézier surfaces. Examples are provided to illustrate the process of construction and comparison is made between various surface bounding volumes. Furthermore, as a starting point for the construction, we provide a way to compute hodographs of triangular Bézier surfaces and improve the algorithm for computing the bounding cone of a set of vectors.     

基于三角范数的多模态手指生物特征的分数层融合方法

多模态的生物特征融合已成为目前生物识别研究领域的主要发展趋势,从防伪性角度出发,满足普适性和易采集、易接受性的应用需求,提出了基于手指静脉,并结合指纹、指关节纹和指形的分数层融合来实现多模态生物特征的身份认证方案。实验结果表明,本文提出基于Sugeno-Weber三角范数的分数层融合方法,能够增大类内与类间匹配分数分布间的距离,提高了多模态生物特征的身份认证性能。