GRIN透镜在细径内窥镜中的应用

介绍在细径内窥镜中ＧＲＩＮ透镜的应用原理及其设计方法。     

纳米硅量子线的发现与研究

一维纳米材料是当今介观物理学研究的前沿领域．文章报道了一种利用脉冲激光成功地制备纯度高、直径分布均匀的纳米硅量子线（ＳｉＮＷｓ）的方法，介绍了纳米量子线的形貌、显微结构、生长机理和物理性能研究的最新结果．纳米硅量子线的发现具有重要的科学意义和潜在的应用前景．     

Role of stationary photon statistics in a high-Q cavity mode while it is exciting the active laser medium

It has been shown by Yu. M. Golubev, M. I. Kolobov, and I. V. Sokolov, Zh. éksp. Teor. Fiz. 111, 1579 (1997) [JETP 84, 864 (1997)], that when an optical cavity is excited by external radiation from a sub-Poisson laser the cavity mode may be in either a sub-Poisson or a Poisson stationary state. This is not important for a resonant medium which is excited into the upper laser level while interacting with this mode inside the cavity. The degree of regularity of the excitation will be identical to that of the initial light flux incident on the cavity, and this ultimately ensures the same sub-Poisson lasing as for strictly regular pumping of the resonant medium. Zh. éksp. Teor. Fiz. 113, 1223–1234 (April 1998)     

Positron annihilation in polycrystalline metals

The empirical relation θ _p ⁶ /I _p=aK (where θ _p is the limiting angle of the parabolic component in the angular distributions of annihilation photons in metals, I _p is the integrated contribution of this component, K=1, 2, 3, ... is an integer, and a is a constant independent of the type of metal) observed earlier has been tested on magnesium, aluminum, copper, zinc, lead, and bismuth samples. The validity of this relation has been substantiated. The value of the dimensionless constant a has been determined and was found to coincide within experimental error with the result obtained in previous measurements. It is shown that the value of K for the same metal but for different samples may be different. It is conjectured that this may be due to different defect concentrations in samples. Fiz. Tverd. Tela (St. Petersburg) 40, 600–602 (April 1998)     

Implementation of secure digital communication by hyperchaoticsynchronisation

By active-passive-decomposition synchronisation, the application of the one-way coupled ring map lattice hyperchaotic system in secure digital speech communication is demonstrated. Synchronisation guarantees strong security and recovery without error     

Determination of tyrosine traces by adsorption voltammetry of its copper (II) complex

The electrochemical behavior of the copper-tyrosine complex has been studied by linear-sweep adsorption voltammetry. In 0.02 mol/L Na₂HPO₄ buffer solution (pH=9.6), the complex can be adsorped on a hanging mercury drop electrode and reduced at a peak potential of about –0.42 V (vs. SCE). The secondary derivative peak height is linear proportional to the concentration of tyrosine in the range 1.0×10^–7–5.0×10^–5 mol/L. The detection limit is 5×10^–8 mol/L.Project supported by the Provincial Science Foundation of Shandong Province     

基于小波变换的医学图象压缩编码

本文研究了医学图象小波变换系数的统计特征。根据医学图象的特点，提出了基于小波变换的医学图象编码方法。实验表明，这种方法具有较好的压缩编码性能，优于JPEG标准。同时，它支持逐次浮现式传输，从而能满足医学图象存储、通信、检索的需要。     

A microprocessor-based toggle-control lighting system

Analysis, design, practical consideration, and implementation of a microprocessor-based toggle-control lighting system are presented. The system is primarily configured with a power factor corrector (PFC), a square-wave voltage generator, a manually controlled toggle switch, and two relays. Toggling the toggle switch can select a different number of lamps in operation, resulting in a mutual dimming feature. A fluorescent lamp lighting system with this specific ballast gains the merits of lower system cost and more flexibilities in lighting fixture design, as compared to conventional systems