受大气湍流影响的光学波前模拟方法研究

介绍了模拟自适应光学系统中受大气湍流影响的光学波前的四种方法，即基于Zernike多项式的K—L函数展开法、小波法、Fourier法以及ARMA法。分析比较了四种方法模拟精度和速度。结果表明，前两种方法不论是精度还是速度上都比较好，更适合湍流波前的模拟。     

振幅起伏对自适应光学系统的限制

本文讨论了补偿前以及经柔形镜对位相畸变完全校正后的光强分布和斯特列尔比,分析了振幅起伏对自适应光学技术的基本限制。结果表明:振幅起伏的影响最严重时补偿后的中心光强仅为衍射极限的一半,斯特列尔比的极限值在最低时为0.5。     

聚焦光束模拟湍流效应自适应光学补偿实验

报道了聚焦光束传输模拟湍流效应校正实验研究，描述了短曝光情况下，补偿效率积分概率的意义，给出了本套自适应光学系统补偿效率与变形镜驱动器的光束发射直径上的平均间中距和湍流相干长度的系统定标关系。     

基于趋势关联遗传算法的系统参数辨识

在利用遗传算法的系统参数辨识中 ,利用了灰色理论中的趋势关联分析方法来构造遗传算法的适值函数 ,在适值函数的选择上兼顾了“接近性”和“相似性”的要求 ,仿真结果证明 ,本方法克服了常规遗传算法容易早熟的缺点 ,取得了满意的效果 .     

激光谐振腔内激活介质像差效应的数值分析

根据气体激光器谐振腔的衍射理论和Ｚｅｒｎｉｋｅ多项式，导出了谐振腔光场振幅分布表达式。用数值分析的方法研究了在不同的相位扰动下，稳腔和非稳腔功率和模式分布曲线。     

环形激光光束的波前复原算法比较

 针对环形激光光束净化自适应光学系统中的波前传感器子孔径与变形反射镜驱动器布局，仿真比较了直接斜率法、区域法的Fried模式和Southwell模式三种波前复原算法, 其中, 直接斜率法的波前校正能力及稳定性均为最好。     

用结构适应实现不同系统之间的完全同步

本文研究不同系统之间的完全同步.按照我们在中提出的观点,建立了一种在结构适应基础上的自适应方法.我们认为这种自适应性是比较正确地反映了复杂系统中自适应的基本特征.我们从控制论的控制器的设计和物理上相互耦合作用两种观点证明了方法的正确性.     

短波SFH/MFSK系统的自适应选频

采用伪误码探测的方法，对ＳＦＨ／ＭＦＳＫ系统的误码率进行了实时的探测，从而为在跳频频段内选取可跳频的频点，建立跳频点优劣评价表提供了依据．从理论上验证了该方案的可行性，并给出了具体的实现方案图以及计算机模拟的结果     

An adaptive Cartesian grid generation method for ‘Dirty’ geometry

Traditional structured and unstructured grid generation methods need a ‘water‐tight’ boundary surface grid to start. Therefore, these methods are named boundary to interior (B2I) approaches. Although these methods have achieved great success in fluid flow simulations, the grid generation process can still be very time consuming if ‘non‐water‐tight’ geometries are given. Significant user time can be taken to repair or clean a ‘dirty’ geometry with cracks, overlaps or invalid manifolds before grid generation can take place. In this paper, we advocate a different approach in grid generation, namely the interior to boundary (I2B) approach. With an I2B approach, the computational grid is first generated inside the computational domain. Then this grid is intelligently ‘connected’ to the boundary, and the boundary grid is a result of this ‘connection’. A significant advantage of the I2B approach is that ‘dirty’ geometries can be handled without cleaning or repairing, dramatically reducing grid generation time. An I2B adaptive Cartesian grid generation method is developed in this paper to handle ‘dirty’ geometries without geometry repair. Comparing with a B2I approach, the grid generation time with the I2B approach for a complex automotive engine can be reduced by three orders of magnitude. Copyright © 2002 John Wiley & Sons, Ltd.     

An Advanced Signal Processing Technique Designed for Multilevel Signal Optical Disc System

We propose a novel signal processing technique by which we can increase the effective signal to noise ratio of optical discs. This technique is capable of reducing the influence of random noise even when the playback signal contains a distortion. We apply this signal processing technique to single carrier independent pit edge recording optical disc system. When a linear recording density of 0.2 μm/bit and a track pitch of 0.8 μm for an optical pickup is used in a DVD pickup (γ =635 nm, NA=0.6), the experimental results show that the system can obtain tangential and radial skew margins of ±0.5° and ±0.75°, respectively. From the experimental results, we estimate that the proposed method is capable of increasing the capacity of DVD by a factor of about 1.2.