掺氢与激励电路对钡蒸气激光输出特性的影响

对用Blumlein电路放电激励的钡蒸气激光在掺氢和不掺氢时的输出特性进行了实验研究.结果表明，用掺氢1.5%的氖气作缓冲气体能使激光功率增加近2倍.在此基础上，进一步比较了相互作用电路与Blumlein电路时钡蒸气激光的输出特性，发现相互作用电路能显著提高钡蒸气激光的输出功率和效率，获得了3W最大功率和0.4%效率的1.5μm波长激光输出.测量并分析了各工作参量与激光功率之间的关系，定性解释了掺氢与相互作用电路的作用机理 . 关键词： Blumlein电路 相互作用电路 掺氢 钡蒸气激光     

聚乙烯基咔唑与Alq3混合薄膜的发光性能与能量传递过程

研究了Alq3与聚乙烯基咔唑(PVK)按不同比例的混合体系制备的薄膜的发光特性.通过对混合薄膜的吸收光谱、激发光谱和发射光谱的分析，研究了PVK与Alq3之间的 能量传递规律.当Alq3与PVK的质量比为1∶7时，能量传递效率最高.用一个由单链模 型扩展到包括杂质的哈密顿量对实验进行模拟，发现该模型能够较好地解释有关的实验结果. 关键词： 吸收光谱 激发光谱 发射光谱 能量传递     

强非线性吸收下高斯光束Z-扫描衍射理论模型

 摘要：在同时考虑非线性折射和非线性吸收的情况下，借助光的衍射理论，研究了Z-扫描技术的衍射理论模型，分析了非线性折射和非线性吸收同时存在时Z-扫描曲线的形状特征和变化规律。数值计算表明，非线性吸收相移和非线性折射相移的比值是影响接收小孔输出光功率的重要因素。要想得到好的光限幅效果，应选取非线性相移比值远小于1或远大于2的非线性材料。     

Two-Layered Poly-o-phenylenediamine/Polyaniline Composite: Electrosynthesis and Spectroelectrochemical Properties

Spectroelectrochemical properties of poly-o-phenylenediamine (PPD) and the synthesized composite of PPD and polyaniline—two chemically related polymers containing an amino-substituted benzene ring but having different conduction nature—are studied. The polyaniline synthesis on PPD-modified electrodes involves stages of the reaction initiation, the copolymer formation, and the formation of a polyaniline layer at the copolymer/solution interface.     

Elliptic and parabolic problems in unbounded domains

We consider elliptic and parabolic problems in unbounded domains. We give general existence and regularity results in Besov spaces and semi‐explicit representation formulas via operator‐valued fundamental solutions which turn out to be a powerful tool to derive a series of qualitative results about the solutions. We give a sample of possible applications including asymptotic behavior in the large, singular perturbations, exact boundary conditions on artificial boundaries and validity of maximum principles. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Non-protein amino acids in peptide design

An overview of the use of non-protein amino acids in the design of conformationally well-defined peptides, based on work from the author’s laboratory, is discussed. The crystal structures of several designed oligopeptides illustrate the useα-aminoisobutyric acid (Aib) in the construction of helices, D-amino acids in the design of helix termination segments and^DPro-Xxx segments for nucleating ofβ-hairpin structures.β- andγ-amino acid residues have been used to expand the range of designed polypeptide structures. Dedicated to Professor C N R Rao on his 70th birthday     

A monotone iterative scheme for a nonlinear second order equation based on a generalized anti–maximum principle

In this paper, a generalized anti–maximum principle for the second order differential operator with potentials is proved. As an application, we will give a monotone iterative scheme for periodic solutions of nonlinear second order equations. Such a scheme involves the L^p norms of the growth, 1 ≤ p ≤ ∞, while the usual one is just the case p = ∞.     

Parabolic Capacity and Soft Measures for Nonlinear Equations

We first introduce, using a functional approach, the notion of capacity related to the parabolic p-Laplace operator. Then we prove a decomposition theorem for measures (in space and time) that do not charge the sets of null capacity. We apply this result to prove existence and uniqueness of renormalized solutions for nonlinear parabolic initial boundary-value problems with such measures as right-hand side.     

工程施工中运输网络优化方案

施工工地运输方案的优化设计可以归结为 :按施工期要求设计运输线路或验证已有线路通行能力 ,计算总线路中影响提高流量的关键路段 ,取得最小费用最大流 .本文运用图论理论这一数学工具把实际问题抽象为有向网络 ,进而建立数学模型 .此方法理论上严密 ,解题步聚直观清晰 ,对水利、公路、水路、铁路等其它运输系统有普遍意义 .     

NECESSARY CONDITIONS FOR OPTIMAL CONTROLS OF SEMILINEAR ELLIPTIC VARIATIONAL INEQUALITIES INVOLVING STATE CONSTRAINT

This paper deals with maximum principle for some optimal control problem governed by some elliptic variational inequalities. Some state constraints are discussed. The basic techniques used here are based on those in [1] and a new penalty functional defined in this paper.