Effect of Both Adiabatic and Non-Adiabatic Atomic Motion in Generalized JC Model

This paper deals with the dynamic behavior of atom-evolu tion affected by motion of atomic mass-center in a high Q cavity. A generalized JC model is treated on this problem. The adia-batic condition is presented also in an explicit form. The time-evolution of the wavefunction is obtained, via quantum high-order adiabatic approximation (HOAA). Then the transition probability and average energetic distributions of each part at any time are discussed.     

Non-Abelian Induced Topological Action for Slowly Changing Quantum System and Non-Adiabatic Corrections

The induced topological action relevant to the non-Abelian Berry's phase factor (NABPF) is derived by combining the high-order adiabatic approximation (HOAA) method with Kuratsuji and Iida's adiabatic path integral formulation. The non-adiabatic corrections for the transition amplitude are thereby obtained and the corresponding graphic representations are defined for convenience in the calculation. The gauge invariant properties and the dynamical implications of the non-Abelian induced topological action are also analyzed in detail.Finally, some explicit calculations for a model of physics are carried out as examples.     

量子微腔中原子俘获的绝热微扰分析

详尽地研究了驻波腔场中两能级原子运动的能量转移和动力学演化的非绝热修正。从而定量地阐述了实现原子俘获的绝热近似条件。     

一种应用相息图对灰度图像信息进行隐藏的方法

一幅灰度图像的相息图被隐藏于一幅宿主图像中,该相息图是采用基于相息图迭代的双随机相位加密技术得到的.由于采用仅含有位相信息的相息图作为待加密灰度图像信息的载体,因而与隐藏图像同时具有振幅和相位信息的情况相比较,需要隐藏的信息量大大降低,从而可在对宿主图像影响较小的情况下,提高提取信息的质量;并可有效地提高信息提取时的光学效率,并且对二元图像信息的隐藏也同样适用.水印图像的剪切对隐藏信息提取质量的影响也被分析,模拟实验结果证明了所采用方法的有效性. 关键词： 灰度图像 相息图 信息隐藏     

基于Wigner-Ville分布的宽带回波瞬时多普勒估计方法

研究了基于Wigner-Ville分布的宽带回波瞬时多普勒估计方法。利用时频分析特有的时、频特征分离的特点,通过信号Wigner-Ville分布的时频相关,进行回波信号瞬时多普勒的估计,并通过理论证明其等价与传统的多普勒估计方法;在此基础上,本文提出了一种基于互Wigner-Ville分布峰值估计的瞬时多普勒估计方法。通过仿真研究,发现基于互Wigner-Ville分布峰值估计的方法具有更低的估计信噪比门限,大大降低了运算量,有利于工程实时应用。     

Hilbert assisted wavelet transform method of optical fringe pattern phase reconstruction for optical profilometry and interferometry

A Hilbert assisted wavelet transform (HWT) method is presented for phase reconstruction of 3D profilometry and interferometry. A rigorous mathematical demonstration about this HWT method is given in this paper. An important conclusion that the phase of the optical fringe pattern is equal to the phase of its HWT coefficients on the ridge is theoretically clarified. The strict relation between the scale parameter and the phase gradient (also called the angular frequency) of the fringe pattern is also given. Computer simulations and experiments reveal the validity of the method and the correctness of the mathematical demonstration. Since the filtering process is avoided in this method, it can deal with the frequency overlapping problem to a certain extent. Applications of this method in both optical profilometry and interferometry are shown and discussed in the experiment section.     

A two-way marching coupled-mode method for range-dependent propagation

##正##An efficient,accurate,and numerically stable coupled-mode solution is presented for acoustic propagation in a range-dependent waveguide.This method is numerically stable due to the appropriately normalized range solutions introduced in the formulation.In addition,by combining a forward marching and a backward marching,this method provides accurate solutions for range-dependent propagation problems,especially those characterized by large bottom slope angle and/or high impedance contrast between water and the bottom.Furthermore,this two-way solution also provides high efficiency,which is achieved by applying the single-scatter approximation.Numerical examples are also provided to demonstrate the efficiency,accuracy, and stability of this method.     

Analytical and numerical solutions of the Schrödinger–KdV equation

The Schrödinger–KdV equation with power-law nonlinearity is studied in this paper. The solitary wave ansatz method is used to carry out the integration of the equation and obtain one-soliton solution. The G′/G method is also used to integrate this equation. Subsequently, the variational iteration method and homotopy perturbation method are also applied to solve this equation. The numerical simulations are also given.     

水平变化波导中声传播问题的高效稳定耦合简正波解

提出了一种高效、精确而且数值稳定的耦合简正波方法,用于求解水平变化波导中的声传播问题。与现有的数值模型相比,本方法采用合理的归一化距离解,极大地提高了数值稳定性;通过结合一个前向传播过程和一个后向传播过程,该方法极大地提高了计算精度,可用于精确求解水平变化波导中的声传播问题,尤其适用于大角度斜坡以及海底与海水声阻抗差别较大的问题;此外,通过采用单次散射近似,该方法极大地提高了计算效率,而且对计算条件要求较低。从数值结果可以看出,本方法是一种高效、精确而且数值稳定的求解水平变化波导声传播问题的耦合简正波方法。     

Novel method for measurement of retardance of a quarter-wave plate

A novel and simple method used for measurement of retardance of a quarter-wave plate employing two polaroids and a right-angle prism is reported. The theoretical analysis of the principle is given taking the Jones matrix as a mathematical tool. The uncertainty of the method is theoretically analyzed. An application example is also given. The measured result of the example is verified with a test. The main advantage of this method is that it can completely determine the retardance value, which overcomes the shortcomings of the existing methods reported before for determining only the multi-value function values, such as cosine or tangent value of the retardance. In addition, this method is also accurate, easy to operate and can also be used for the retardance measurement of other retardation plates.     

An uncertain information fusion method based on possibility theory in multisource detection systems

In multisource detection systems, the information representing detection characteristics is uncertain, also the relationship between detection characteristics and detection performance has uncertainty, meanwhile the influence degrees of each characteristic on the performance are also different. In order to represent and process these uncertain information effectively, this paper proposes an uncertain information fusion method based on possibility theory. Firstly, possibility distributions of a series of characteristic parameters about sensor information are constructed, and effective detection characteristics are extracted through the similarity measurement according to the similarity based on distances. The uncertain relationship between detection characteristics and detection performance is quantified, and a certainty calculation method of possibility distributions is proposed based on the combination of holistic and local characteristics. According to the above certainty, the weights of each characteristic are obtained to achieve the fusion of possibility distributions. Finally, the metallic and nonmetallic adhesive structure is taken as a case, and this case shows that this method not only considers the differences of the various characteristics contributed on adhesive performance, but also can achieve the fusion of possibility distributions under different situations. It is a more reasonable fusion method and fits the reality well in practice, also it provides new method and new idea for the fusion of possibility distributions.     

用快速傅氏变换作次声信号的动态谱分析

本文提出了应用小型数字计算机和快速傅氏变换作次声信号动态频谱的分析方法,实验证明这种方法行之有效,且容易实施,从而克服了模拟分析器难以克服的困难。本文介绍数字化频谱分析的一般原理,着重讨论记录在纸上的次声信号的采样和分析方面的有关问题,给出了用FORTRAN语言编写的动态谱分析计算程序和绘图程序,和一个实际例子的分析结果。     

Control of coexisting attractors via temporal feedback

We propose a method for controlling coexisting attractors in multistable dynamical systems. In this method, the feedback for an initial duration of time can drive the system to the desired state. We have illustrated this method by considering temporal feedback in autonomous as well as non-autonomous dynamical systems. The experimental realisation of the proposed method is also presented.     

泡泡布点方法及其并行性

针对无网格和有限元方法中的布点需求,借鉴分子动力学方法和泡泡网格化方法的思想和处理技术,提出一种单纯的布点方法--泡泡布点方法.将区域内的点看作有相互作用力的泡泡,通过动态模拟得到高质量的点集,模拟中不需要网格连接.算例显示,生成的均匀点集和非均匀点集都具有很好的结构和渐进性,并对复杂区域具有很好的适应性.同时由于相互作用力的局部性,该布点方法类似于短程作用的分子动力学模拟,拥有潜在的并行性.通过初步的并行算例,验证了其并行化的可行性.     

一种主动浮标阵的定位解算方法仿真分析

在研究单枚主动定向浮标定位原理的基础上,推导出一种利用最小二乘法解算多枚浮标的定位结果的方法,并针对圆阵就阵元个数、圆阵半径以及测距误差对该解算方法的性能影响进行了数值仿真分析。仿真结果表明,该算法在测向均方误差较大或者目标在距离圆内的情况下,性能远优于单枚主动定向浮标;圆阵半径2 km左右,阵元个数在6左右时,该解算方法的性能达到最佳。此外,该解算算法很容易被扩展至三维定位问题,因此有一定的理论和应用价值。     

A Simple Bi-directional Mode Expansion Propagation Algorithm Based on Modes of a Parallel-plate Waveguide

The bi-directional mode expansion propagation algorithm (BEP) is known to be an accurate and efficient method for modelling field distribution in high-index contrast waveguide structures with strong back-reflections like Bragg gratings and photonic crystals. The main difficulty of this method is that for lossy structures, the propagation constants of modes are to be searched in the complex plane. To speed-up this procedure, a two-step algorithm for eigenmode calculation based on the expansion into the modes of an empty metallic waveguide has recently been proposed. Proper truncation rules possessing good convergence of the expansion method for both TE and TM modes have also been recently published. In this contribution, both these approaches are combined in the development of an extremely simple version of the two-dimensional BEP method that makes use of the field expansion into the eigenmodes of a parallel-plate waveguide. The method is strictly reciprocal and appeared to be computationally reliable also for strongly lossy structures. High numerical stability is ensured using the scattering matrix formalism, and an efficient method of calculating Bloch modes for symmetric as well as asymmetric periodic waveguide structures is adopted. A wide range of applicability of the method is demonstrated by a few examples.     

Construction of exact solutions to a family of wave equations by the functional variable method

The method developed in this work uses an alternative functional variable method to construct exact travelling solutions to a class of nonlinear wave equations. It is shown that it is possible to obtain by a direct treatment the general solutions to some important nonlinear model equations which arise in a wide variety of physical problems. We have also presented some interesting typical examples to illustrate the application of this method.     

基于液晶分划和数字图像处理的正透镜焦距测量研究

讨论了一种基于LCD、CCD和数字图像处理的正透镜焦距测量方法 ,是光电法自动化测量光学系统多个参数的一种有益的探讨。用液晶屏显示分划图形取代平行光管的分划板 ,用CCD在接收方采集数字图像并送入计算机 ,通过图像处理和分析得出被测透镜的焦距。运用叠加的方法提高图像的信噪比 ;结合重心法和平行线拟合方法求取平行线对的间距 ;应用高精度焦距标准透镜标定数字图像和实际像之间的比例关系。详细介绍了测量和图像处理的方法 ,进行了公式推导和误差分析 ,并给出了实验结果     

Application of the high-resolution Godunov method to the multi-fluid flow calculations

In this paper, we have numerically solved the multi-fluid problems using an operator-split two-step high-resolution Godunov PPM (parabolic piecewise method) for the flow in complex geometries. By using the front capturing method,the PPM integrator captures the interface in the solution process. The basic multi-fluid integrator is coupled to a Cartesian grid algorithm where a VOF (volume of fluid) representation of the fluid interface is also used. As an application of this method, we test the 2D interracial advection example and simulate an experimental hypervelocity launcher model from Sandia National Laboratories. The computational design of the hypervelocity launcher is also given in the paper.     

李代数方法在分子振动光谱研究中的应用

通过对动力学对称性的介绍,引出构造分子体系Hamiltonian的方法,并介绍李代数方法处理分子"振动-振动耦合"、"振动-转动耦合"Hamiltonian的一般步骤.还以HCO分子体系为例,说明如何选取特定的群链来构造Hamiltonian,并论证了对于该体系群链的唯一性.最后还对一些李代数方法在分子光谱中的其他应用(例如局域模,多原子分子的振转光谱研究)作了初步的介绍,并对于这一方法的不足和局限性做了论述.