实时光电混合联合变换相关器单元的实验研究

本文根据联合变换相关的原理，提出了一种实时光电混合联合变换相关器，它采用一个液晶光阀作为输入器件，用另一个液晶光阀记录和显示联合功率谱，所给出的实验结果证实了该系统设计及性能分析的正确性。     

Geometrical frustration in 2D optical patterns

In the case of 2D optical patterns, frustration comes from the interplay between the physical constraints (light-matter interaction) and the geometrical constraints (cavity length and structure). Depending on the dynamical parameters, we are able to single out two distinct behaviors. For small diffusion and close to threshold, the system is forced to fulfill the geometrical constraints giving rise to a phase dynamics of quasicrystals. For larger diffusion, the system fragmentates into spatial domains giving rise to a competition between different patterns. By means of a geometrical argument, we show that the spatial distribution of domains is related to the symmetry imposed by the geometrical constraint and that the domain borders are disinclination defects. These defects being the nucleation centers of spatial domains, they trigger the onset of pattern competition. Received 27 December 1999 and Received in final form 29 March 2000     

模糊Hopfield网络及其模糊聚类功能研究

本文提出了一种能进行模糊逻辑计算的Ｈｏｐｆｉｌｅｄ型人工神经元网络，ＦｕｚｚｙＨＮ的神经元对应模式集合中的元素，模式间的模糊相似关系作为联结神经元的权值矩阵被存储在ＦｕｚｚｙＨＮ中。本文对ＦｕｚｚｙＨＮ的稳定性及模糊聚类功能进行研究，获得了良好的理论分析结果和实验研究结果。     

Consideration of Fractional Fringe Method on the Basis of the Least Squares Method

The traditional fractional fringe method has been applied to measure 1-dimensional size of a block gauge using multiple wavelengths. Recently, similar methods have been used in pattern interferometry and also in pattern projection profilometry. However, the technique does not seem to be based on a well-established principle. In this paper, the fractional fringe method is formulated on the basis of the least squares method and on its basis effects of errors in fractional fringes and wavelengths are analyzed and the effective selection of wavelengths is considered.     

Interference Pattern in Resonance Fluorescence from Two Atom System

It is studied the fringe contrast factor of the fluoresence field emitted by two interacting atoms driven by a coherent field and a squeezed vacuum field. The result shows that both the Rabi frequency and the phase difference between the coherent field and the squeezed vacuum field affect the interference pattern significantly. Nonzero phase difference and intermediate Rabi frequency can lead to the vanishing of the dark center.     

多光束莫尔偏折术的探讨

本文探讨了莫尔偏折术应用的新方法——多光束莫尔偏折术.该法无需测量莫尔条纹偏折角,而是记录条纹对比度最好时试件的位置.文章阐述了其基本原理,并在光栅栅距和光楔楔角测量上进行了实验验证,取得较好的结果.     

Wave pattern characteristics of a two-phase nozzle flow by shock propagation

In this paper, the wave pattern characteristics of shock-induced two-phase nozzle flows with the quiescent or moving dusty gas ahead of the incident-shock front has been investigated by using high-resolution numerical method. As compared with the corresponding results in single-phase nozzle flows of the pure gas, obvious differences between these two kinds of flows can be obtained. Received 14 June 1996 / Accepted 19 October 1996     

Traffic of Molecular Motors Through Tube-Like Compartments

The traffic of molecular motors through open tube-like compartments is studied using lattice models. These models exhibit boundary-induced phase transitions related to those of the asymmetric simple exclusion process (ASEP) in one dimension. The location of the transition lines depends on the boundary conditions at the two ends of the tubes. Three types of boundary conditions are studied: (A) Periodic boundary conditions which correspond to a closed torus-like tube. (B) Fixed motor densities at the two tube ends where radial equilibrium holds locally; and (C) Diffusive motor injection at one end and diffusive motor extraction at the other end. In addition to the phase diagrams, we also determine the profiles for the bound and unbound motor densities using mean field approximations and Monte Carlo simulations. Our theoretical predictions are accessible to experiments.     

A CCD-based polarization interferometric technique for testing waveplates

A CCD-based polarization interferometric technique is developed to test waveplates. A Babinet compensator is used to produce interference fringes for polarized input and the retardance introduced by the waveplate when inserted in the optical beam is calculated from the fringe shifts using the phase matching technique. A theoretical model is fitted with the observed fringe shifts to get an accuracy of 0.5° in the retardance calculation. The experimental set-up and the measurement of retardance for zero-order and high-order quarter waveplates are discussed. The retardance calculation for a zero-order waveplate is found to be more accurate than the high-order waveplate. This technique can also be used to measure an arbitrary amount of retardance produced by any birefringent waveplate and also to determine its optic axis direction.     

几种傅里叶子的深入比较研究

用于模式识别的傅里叶子主要有基于极半径函数、转角函数和曲率函数等三种方法 ,通过比较研究 ,找出一种运算简便且精度高的傅里叶子。对不同的图形用三种方法分别计算出原函数和傅里叶频谱 ,然后从大到小依次选取k个 (k =1,2 ,… ,N)傅里叶系数进行反变换 ,计算出反变换函数与原函数之间存在的误差 ,根据误差随k变化的曲线判断三种方法的优劣。实验结果表明 ,基于极半径函数的傅里叶子最为理想。将它用于孢子的识别和计数 ,正确识别率达 99%。