Timelike Minimal Surfaces via Loop Groups

This work consists of two parts. In Part I, we shall give a systematic study of Lorentz conformal structure from structural viewpoints. We study manifolds with split-complex structure. We apply general results on split-complex structure for the study of Lorentz surfaces.In Part II, we study the conformal realization of Lorentz surfaces in the Minkowski 3-space via conformal minimal immersions. We apply loop group theoretic Weierstrass-type representation of timelike constant mean curvature for timelike minimal surfaces. Classical integral representation formula for timelike minimal surfaces will be recovered from loop group theoretic viewpoint.     

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.     

一类二阶椭圆型微分方程振动性的判定

利用积分平均和完全平方技巧，给出了一类二阶椭圆型微分方程所有解在R^n的一个外区域Ω上均振动的新的充分条件。     

硅基两维光子晶体的制备和光子带隙特性

利用反应离子束刻蚀设备制备了硅基的两维空气柱光子晶体，并用红外显微镜测试了样品的 反射谱. 理论上用时域有限差分(FDTD)方法计算了样品的光子带隙，从测试结果看光子带隙 和理论计算的光子带隙符合得很好.  关键词： 光子晶体 光子带隙 反射谱 时域有限差方法     

二次谐波系统在浑沌态下的光子统计

数值分析了调制泵浦作用下的二次谐波产生系统的浑沌动力学行为.考虑到混沌运动的遍历性,提出一种研究浑沌态光场光子统计的数值方法,即通过数值积分求解系统动力学方程估计光子数的系统平均.运用这一方法于二次谐波系统,计算了其在浑沌态下的光子统计分布,结果表明是一种超Poisson分布.     

KDP晶体三倍频实验和分析

报道了ＫＤＰ晶体中的三倍频产生的实验研究，计算了比较了直接三倍频过程和级联过程对ＫＤＰ晶体三阶有效非线性系数的贡献，并探讨了ＫＤＰ作为非线性晶体材料三阶非线性系数测量基准的可行性。     

LB膜混合聚集体中极性基团相互作用对光学非线性的影响

通过紫外－可见吸收光谱、压力－面积等温线、二次谐波的测量，研究了不同活性分子混合聚集体的形成对ＬＢ膜光学性质的影响。分子极性基团间的相互作用，使激发态能量及平均偶极矩发生变化，导致ＬＢ膜的光学非线性明显地增强或减弱。     

Paul阱内的压缩效应与量子跃迁

处理一个一维Ｐａｕｌ阱系统中的压缩现象与量子跃迁现象，对于阱内的最强压缩态和共振跃迁（一种极不稳定状态）之间的关系作了阐述，并对利用压缩性质在阱内进行精密测量的可能性作了讨论     

Assignment of conformation-sensitive near-infrared bands in high-spin ferrous haemoproteins. Low-temperature magnetic circular dichroism data

An assignment of the near-infrared bands in the 600–800 nm spectral region observed in magnetic circular dichroism (MCD) spectra of high-spin ferrous haemoproteins is presented. The assignment is based on a relative energy level scheme for iron d-electrons, a comparison of predicted and measured temperature dependences of MCD intensity, a sign of MCD bands and a group theoretical analysis of allowed transitions. The proposed assignment is consistent with the ∼15-nm red shift of the ∼760 nm band on breakage of the Fe-His bond in deoxy-myoglobin at low pH, with low-temperature photolysis experiments available for CO complexes of several haemoproteins. In accordance with the observations, the intensity of the MCD bands for proteins with a sulphur anion of cysteine as proximal haemligand (cytochrome P450 and chloroperoxidase) is predicted to be diminished by at least one order of magnitude compared to that for proteins with an imidazole of a histidine as a protein-derived haemligand (i.e. myoglobin, haemoglobin and horseradish peroxidase). Received: 4 February 1997 / Accepted: 1 May 1997     

A Note on Geometric Structures of Linear Ordered Orthogonal Arrays and (T,M,S)-Nets of Low Strength

The equivalent geometrical configurations of linear ordered orthogonal arrays are determined when their strengths are 3 and 4. Existence of such geometrical configurations is investigated. They are also useful in the study of (T, M, S)-nets.