Ⅱ-Ⅵ族化合物薄膜电致发光

电致发光薄膜是平板显示器的重要材料之一,我们从研究ZnS:Mn,Cu直流电致发光薄膜的大面积稳定发光开始,首次将稀土离子引进直流电致发光薄膜,实现了各色的直流电致发光,并研究其激发机理、过热电子的能量分布、稀土离子的碰撞截面和稀土离子发光中心在晶格中的位置等。在国内首先研制成功ZnS:Mn交流电致发光薄膜计算机终端显示器,并扩大面积到640×480像素(对角线10英寸)。为了实现彩色化显示,研制出稀土离子掺杂的各色交流电致发光薄膜。研究不同稀土离子在薄膜中的浓度猝灭,以便提高薄膜的发光亮度。在致力于实现彩色的过程中,首要的任务是提高蓝色电致发光薄膜的亮度和探索新的蓝色电致发光薄膜材料:从ZnS:TmF₃到CaS:TmF₃,发光亮度有了很大的提高;使SrS:Ce薄膜蓝色电致发光的亮度超过1000cd/m²;同时探索纳米Si和非晶Si/SiO₂超晶格结构的蓝色电致发光。成功地实现了ZnS:Mn/SrS:Ce白色电致发光和SrS:HoF₃三基色线谱发射的白色电致发光,发光亮度也超过1000cd/m²。     

变系数非线性方程的Jacobi椭圆函数展开解

把Jacobi椭圆函数展开法扩展并应用到求解变系数的非线性演化方程,比较方便地得到新的解析解 关键词： Jacobi椭圆函数 变系数非线性方程 类椭圆余弦波解 类孤子解     

Minimal Submanifolds in a Locally Symmetric and Conformally Flat Space

We study minimal submanifolds in the locally symmetric and conformally flat Riemannian manifold and generalize Yau's result obtained in J. Amer. Math. 97 (1975), 76–100.     

Low‐gain adaptive stabilization of semilinear second‐order hyperbolic systems

In this paper low‐gain adaptive stabilization of undamped semilinear second‐order hyperbolic systems is considered in the case where the input and output operators are collocated. The linearized systems have an infinite number of poles and zeros on the imaginary axis. The adaptive stabilizer is constructed by a low‐gain adaptive velocity feedback. The closed‐loop system is governed by a non‐linear evolution equation. First, the well‐posedness of the closed‐loop system is shown. Next, an energy‐like function and a multiplier function are introduced and the exponential stability of the closed‐loop system is analysed. Some examples are given to illustrate the theory. Copyright © 2004 John Wiley & Sons, Ltd.     

类铜离子的电子碰撞参数及其规律

用准相对论扭曲波方法系统地计算了Ｂａ、Ｎｄ、Ｇｄ、Ｙｂ、Ａｕ、Ｐｂ类铜离子组态能级之间的电子碰撞激发强度Ω（ｎｌ－ｎｌ），３≤ｎ≤７，４≤ｎ≤７，同时给出了高能极限的碰撞强度和外推到阈值的碰撞强度，用最小二乘样条方法拟合了全能域碰撞强度及热平均速率系数。对于一个激发过程，用１０个参数可以得到碰撞电子在任意能量下的碰撞强度以及任意温度下的速率系数。     

A novel specimen for investigating the mechanical behavior of elastomers under multiaxial loading conditions

In this paper we describe the design and manufacture of an axial-torsion test specimen, and provide relationships needed when conducting stress-strain characterization experiments with the specimen. The specimen is a short hollow cylinder of rubber bonded between two steel mounting rings, in which simultaneous axial and shear strains are produced via independently controlled axial and twist displacements. We present calculations for the strain-displacement and stress-load relationships, and strain energy density. These relationships have been established and validated via a combination of analytical and experimental techniques, and finite element analysis. We have investigated the extent and effects of strain and stress field non-uniformity in the test specimen. The specimen design is sufficiently simple that a closed-form expression for the strain-displacement relationship has been successfully developed.     

基于阿贝尔黑格斯变量的杨-米尔斯理论的红外阿贝尔化

通过SU(2)规范场的法捷耶夫-Niemi分解给出了有效阿贝尔-黑格斯型作用量的 一个计算方法. 具体指出了该分解中所用的自然规范固定以及阿贝尔投射与杨-米尔斯理论的红外动力学之间的内在关系. 推导出了色电场的一个伦敦型方程.     

A Penrose-like inequality for maximal asymptotically flat spin initial data sets

We prove a Penrose-like inequality for the mass of a large class of constant mean curvature (CMC) asymptotically flat n-dimensional spin manifolds which satisfy the dominant energy condition and have a future converging, or past converging compact and connected boundary of non-positive mean curvature and of positive Yamabe invariant. We prove that for every n ≥ 3 the mass is bounded from below by an expression involving the norm of the linear momentum, the volume of the boundary, dimensionless geometric constants and some normalized Sobolev ratio.     

Spectral Properties of Four-Dimensional Compact Flat Manifolds

We study the spectral properties of a large class of compact flat Riemannian manifolds of dimension 4, namely, those whose corresponding Bieberbach groups have the canonical lattice as translation lattice. By using the explicit expression of the heat trace of the Laplacian acting on p-forms, we determine all p-isospectral and L-isospectral pairs and we show that in this class of manifolds, isospectrality on functions and isospectrality on p-forms for all values of p are equivalent to each other. The list shows for any p, 1 ≤ p ≤ 3, many p-isospectral pairs that are not isospectral on functions and have different lengths of closed geodesics. We also determine all length isospectral pairs (i.e. with the same length multiplicities), showing that there are two weak length isospectral pairs that are not length isospectral, and many pairs, p-isospectral for all p and not length isospectral. Mathematics Subject Classifications (2000): 58J53, 58C22, 20H15.