纵向耦合对垂直腔面发射激光器的影响

考虑到垂直腔面发射激光器中的光子与载流子的纵向耦合,在行波速率方程中引入了纵向耦合因子。利用这个速率方程,讨论了阀值电流与量子阱数目的关系,计算结果表明光子与载流子的纵向耦合是不容忽视的。给出了阀值电流表达式,它表明纵向耦合因子越大,阀值电流越低。     

色散缓变光纤中的调制不稳定性分析

研究了色散缓变光纤中调制不稳定效应,得到了增益谱与光纤纵向色散参量的一般关系式.结果表明,色散缓变光纤较常规光纤具有较宽的增益谱.选取色散级变光纤的色散参量可以获得较大的增益带宽.数值模拟显示,利用色散缓变光纤中的调制不稳定性可以产生高重复率的基本孤子脉冲串.     

应用自适应遗传算法的气动优化设计

对简单遗传算法(SGA)加以改进,形成了气动优化设计中的自适应遗传算法(SAGA)。采用实数编码来表示种群中的个体,不需要进行二进制的编码和解码操作,并针对具体问题设计了杂交和变异算子,提高了优化设计的质量和效率。最后分别以翼型和机翼为例,应用自适应遗传算法对跨音速翼型和机翼的升阻比进行优化设计。     

超短脉冲激光再生与多程放大器的理论分析与实验建立Ⅰ.理论部分

从半经典理论的麦克斯韦－布洛赫方程出发,对种子激光脉冲在再生和多程放大器中的放大过程进行了分析,结合实际的物理条件得出了放大器的峰值输出的解析表达式。     

Nonlinear phase adjustment of selective excitation pulses

A continuous transformation of an RF waveform with a modified Korteweg-de Vries equation or generalization can be used to adjust the phase behavior of a selective excitation pulse while preserving the magnitude behavior of the spin response. This transformation has applications in removing or adding to the nonlinear phase properties of a selected region.     

Nearly Vertical Hopf Bifurcation for a Passively Q-Switched Microchip Laser

Passively Q-switched microchip lasers generate strongly pulsating intensity oscillations that emerge from a Hopf bifurcation point. We show that this bifurcation is nearly vertical and explain why strongly pulsating oscillations are immediately observed as we pass the Hopf bifurcation point. The laser dynamical problem is mathematically a singular perturbation problem which we investigate. The leading order problem is conservative and corresponds to Lotka–Volterra equations.     

The Application of Mode-Locked Laser Technologies to Long Distance Transmission and Control of Soliton

The control scheme of long distance optical transmission is treated based on conception of mode-locked Laser cavity in this paper. The general mode-locking equation of fiber ring soliton Laser is first constructed, then we give the general perturbed nonlinear schrödinger equation, and finally the transmission and control equations of optical soliton communication systems with various different configurations, respectively, are obtained.     

Quantum relativistic theory of an electron in terms of local observables

Dirac equation is reformulated in terms of real local observables, which are mean values of the wave function . The quadrivector current is shown to be a function of the potential vector and of other local observables. The equations describe the evolution of a four dimensional system T, X, Y, Z, and of two scalars, in the coordinate system ct, x, y, z. The current is proportional to the T vector. The Z vector is associated with the spin of the electron. Energy and gauge transformations correspond to rotations in the plane (X, Y). In the presence of a static field, the (real) solutions of the equations appear as eigenfunctions associated with energy eigenvalues. Received 7 September 1998     

On Highest Weight Modules Over Elliptic Quantum Groups

The purpose of this Letter is to define and construct highest weight modules for Felder's elliptic quantum groups. This is done by using exchange matrices for intertwining operators between modules over quantum affine algebras.     

计算应力强度因子的离散分离变量法

提出一种用于数值求解带有一条边界裂纹的多角形区域上的Navier's方程组边值问题的半离散方法。做一个适当的坐标变换后,将原边值问题化为半无限长条上的不连续系数问题。将其半离散化以后,等价于一个常系数常微分方程组的边值问题。进一步,用直接法来求解这个边值问题,便得到原问题的半离散近似解。值得指出的是,这个用分离变量形式给出的半离散近似解自然地具有原问题的奇性。数值例子显示,用该方法可以很方便地计算出在裂纹顶端的应力强度因子的近似值。