离散可积耦合系统零曲率方程的代数结构及其对耦合Volterra系统的应用

基于Lie代数的半直和思想,
建立了离散可积耦合系统的代数结构,
并将这种结构应用到耦合 Volterra 族生成$\tau$-\!对称代数.     

Lehmer序列中的平方数与平方类

设Vn(R,Q)表示参数为R和Q的Lehmer伴随序列.如果R和Q为互素奇数且D=R-4Q>0,我们找出了满足Qn(R,Q)或n1Qn(R,Q)是平方数的所有奇数n.这里,从而改进了文[15]的工作.     

新型有机聚合物光子射频2路移相器的设计

以3dB带宽为12GHz的有机聚合物光子射频2路移相器的理论设计为目标，设计了一种新型的有机聚合物射频（RF）移相器，并对其光波导结构及电极系统进行了仿真。分析了移相器的输出特性，可在两个端口实现360°的连续线性移相，并且输出功率波动小于3dB。该器件移相性能好，体积小，有利于阵列集成。     

An Alternative Approach for Determining Photoionization Rate in H2^＋：Numerical Results

We present an alternative approach for determining the photoionization rate of hydrogen molecules under the interaction of intense light, by calculating the spatial overlap integral between the potential function and the time-dependent wavefunction. The suggested method was applied to varying excitation pulse shapes: square envelope and chirped hyperbolic secant envelope. The computed results confirmed that our method was robust and could be extended to general molecular dynamics calculations.     

A compact graphene Q-switched erbium-doped fiber laser using optical circulator and tunable fiber Bragg grating

We demonstrate a passively Q-switched tunable erbium-doped fiber laser(EDFL)based on graphene as a saturable absorber(SA).A three-port optical circulator(OC)and a strain-induced tunable fiber Bragg grating(TFBG)are used as the two end mirrors in an all-fiber linear cavity.The Q-switched EDFL has a low pump threshold of 23.8 mW.The pulse repetition rate of the fiber laser can be widely changed from 9.3 kHz to 69.7 kHz by increasing the pump power from23.8 mW to 219.9 mW.The minimum pulse duration is 1.7μs and the highest pulse energy is 25.4 nJ.The emission wavelength of the laser can be tuned from 1560.43 nm to 1566.27 nm by changing the central wavelength of the straininduced TFBG.     

基于共振异常的消偏振型窄带滤波器分析

亚波长光栅因光栅参量的不同而具有不同的衍射特性,通过对亚波长光栅参量的合理设计来实现消偏振窄带滤波是一种新的方法与途径。首先分析了基于共振异常的窄带滤波的物理机制及存在条件,讨论了二维亚波长光栅实现消偏振窄带滤波的可能性。然后,利用严格模式理论进行了计算模拟,其计算结果与导波理论所得结果基本吻合,其衍射特性表现出周期性共振异常、敏感的角度依赖性和波长依赖性。最后,讨论了由工艺误差对滤波特性所带来的影响。为具体工艺制作提供了一定的指导。     

Finite-time robust control of uncertain fractional-order Hopfield neural networks via sliding mode control

The finite-time control of uncertain fractional-order Hopfield neural networks is investigated in this paper. A switched terminal sliding surface is proposed for a class of uncertain fractional-order Hopfield neural networks. Then a robust control law is designed to ensure the occurrence of the sliding motion for stabilization of the fractional-order Hopfield neural networks. Besides, for the unknown parameters of the fractional-order Hopfield neural networks, some estimations are made. Based on the fractional-order Lyapunov theory, the finite-time stability of the sliding surface to origin is proved well. Finally, a typical example of three-dimensional uncertain fractional-order Hopfield neural networks is employed to demonstrate the validity of the proposed method.     

单摄像机虚拟立体视觉测量技术研究

以双目立体视觉传感器三维测量模型为基础,提出了一种用于测量空间三维点坐标的低成本单摄像机模型。该模型利用光学成像,把单摄像机镜像为一对虚拟摄像机,在一个CCD像面上采集到同一物体存在视差的两幅图像,从而恢复空间点的三维信息。讨论了单摄像机传感器测量空间三维点坐标的基本原理,建立了单摄像机传感器的测量模型,克服了双摄像机系统中成本高、切换采集左右摄像机的图像使检测速度减慢等诸多缺陷,为空间三维点的精密测量提供了经济、快速、有效的测量途径。实验表明．传感器可实现约0．8％的相对测量精度．证明了本方案合理、有效。     

非局域程度对向列相液晶中空间光孤子的影响

理论分析了非局域程度对向列相液晶中(1+2)维空间光孤子的影响.得到了非线性系数以及特征长度和预倾角的关系,并且给出了强非局域性的非线性薛定谔方程,最终得到了单孤子和临界功率的解析解.实验上,通过改变偏压从而间接测量了向列相液晶中的临界功率,并与数值模拟结果相结合与理论结果进行了比较,发现基本相符. 关键词： 空间光孤子 非线性系数 非局域程度 临界功率     

一种基于圆内接直角三角形的圆检测方法

提出一种基于圆内接直角三角形的圆检测方法.创建基于有效像素位置的数组存储空间,将图像空间的搜索任务转移到压缩的数组空间中完成,配以特定的搜索算法,降低了该方法复杂度.在存储空间中分级别搜索直角三角形,将圆参量的求解转化为三角形参量的计算,避免了反复的平方、开方运算,减少了运算时间.在结果计算过程中,将单个直角三角形求解结果进行聚合,最终得到合理全局解.合成图以及实际图像的实验结果表明,该方法用于一般图像的圆检测时,具有独特的抑制噪声以及非圆上边缘点干扰的优势,实验快速、可靠,具有可重复性,检测精度小于1 pixel.