Strip Waveguide Directional Coupling Modulator with Equivalent Refractive Index

The equivalent refractive index(ERI) method is employed to analyze the function of the strip waveguide directional coupling modulator(SWM). Through deducing the diagnostic equation of the Enm^x mode of the four--layer media film waveguide equivalent to the SWM,the transmission constant of the symmetrical mode of the positive phase and negative one and the coupling length of powerful transference are obtained. The veracity of ERI is validated with the example of Enm^x basal mode under the condition of comparing the three results of ERI,EIM and Marcatili.     

应用多重尺度法推导浅水波方程和悬沙扩散方程

根据潮流、波浪及湍流运动尺度不同的特点，引入奇异摄动理论中的多重尺度法，应用导数展开法分离Navier-Stokes方程和质量传输方程，导出了波浪作用下的浅水环流方程、潮位和潮流作用下的浅水波方程及波流联合作用下的悬水扩散方程，用数学方法解释了潮流波浪的相互作用和影响。并与雷诺方程进行了比较。为研究海岸动力因素运动规律和诸动力因素与海岸相互作用奠定了理论基础。     

导波光学技术在测量“夹心”光学薄膜各向异性方面的应用:不同膜堆结构中同类薄膜特性的比较

本文介绍了应用导波光学技术测量“夹心”光学薄膜的特征参数的方法,并研究了比较简单的结构(由二、三层膜组成),检测到了高折射率薄膜的各向异性。从不同结构的膜系中的同类薄膜的比较中发现了单层膜与膜堆中对应的“夹心”膜之间在折射率和各向异性上的差别。     

Brain waves and problems of psychology.

Since World War II numerous advances have been reported dealing with the relationships between brain waves and psychological processes. These studies are summarized and discussed under the categories of sleep and wakefulness, sensation, response processes, perception, and complex processes. "Each new discovery seems to reveal the brain as an even more versatile organ than was previously appreciated. The major advances in the areas discussed have unquestionably stemmed from the delineation of anatomical connections and physiological functions of the reticular formation of the lower brain stem and the diffuse thalamic projection system." 206 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transverse Electromagnetic Standing Waves: A New Length Scale in Superconducting Thin Films

The resonance condition for transverse standing waves in superconducting thin films is derived and shown to relate the film's thickness (d) to its material parameters. Surface reactance (X_s) data are shown to be important in interpreting the surface resistance (R_s) data: their relative magnitude bears on the detectability of these standing wave resonances. The periodicity of these resonant thicknesses of otherwise identical films ( d) is a new length scale in superconductors and is given by , where is the complex electromagnetic penetration depth of the superconducting thin film. Many signatures of these standing waves, including an oscillatory transition temperature (T_c) vs. d and an anticorrelation between T_c and the normal state resistance—as a function of the film thickness—collaborate with data reported in the literature. It is important to delineate the contribution of this length scale in superconducting thin-film data that has been known for more than 30 years as, inter alia, the quantum-size effect, the Wyatt–Dayem effect, nonequilibrium superconductivity, and the Carlson–Goldman mode. This is the first report to suggest these standing waves are a possible origin to these phenomena. To further test if noted experimental data are consistent with the standing waves discussed herein, X_s experiments to compliment R_s experiments are proposed.     

一般密度分布的分层流体中内孤立波三阶理论

在浅水假定下,可以用KdV方程描述一阶内孤立波演化,其单个孤立波解有熟知的“Sech”波形,波速与波幅呈线性关系,波长与波幅的平方根成反比。本文借助计算机代数软件一MATHEMATICA,这种理论推广到三阶,得知高阶项满足线性化非齐次KdV方程,并得到波形和波速的三阶修正以及波长的二阶修正。在Boussinesq近似下讨论了有线性基本剪切流动与不变的Brunt-Vaeisalae频率这一特殊情形。     

Operator separation of variables for adiabatic problems in quantum and wave mechanics

Linear problems in mathematical physics where the adiabatic approximation is used in a wide sense are studied. From the idea that all these problems can be treated as problems with an operator-valued symbol, a general regular scheme of adiabatic approximation based on operator methods is proposed. This scheme is a generalization of the Born–Oppenheimer and Maslov methods, the Peierls substitution, etc. The approach proposed in this paper allows one to obtain “effective” reduced equations for a wide class of states inside terms (i.e., inside modes, subbands of dimensional quantization, etc.) with possible degeneration taken into account. Next, by application of asymptotic methods, in particular the semiclassical approximation method, to the reduced equation, the states corresponding to a distinguished term (effective Hamiltonian) can be classified. It is shown that the adiabatic effective Hamiltonian and the semiclassical Hamiltonian can be different, which results in the appearance of “nonstandard characteristics” while passing to classical mechanics. This approach is used to construct solutions of several problems in wave and quantum mechanics, particularly problems in molecular physics, solid-state physics, nanophysics and hydrodynamics.     

On the Comparison of Timoshenko and Shear Models in Beam Dynamics

The classical Timoshenko beam model and the shear beam model are often used to model shear building behavior both for stability or dynamic analysis. This technical note questions the theoretical relationship between both models for large values of bending to shear stiffness parameter. The simply supported beam is analytically studied for both models. Asymptotic solutions are obtained for large values of bending to shear stiffness parameter. In the general case, it is proven that the shear beam model cannot be deduced from the Timoshenko model, by considering large values of bending to shear stiffness parameter. This is only achieved for specific geometrical parameter in the present example. As a conclusion, the capability of the shear model to approximate Timoshenko model for large values of bending to shear stiffness parameter is firmly dependent on the material and geometrical characteristics of the beam section and on the boundary conditions.     

Viscous Effect on the Roll Motion of a Rectangular Structure

The viscous effect on the roll motion of a rectangular structure was investigated in a two-dimensional wave tank. The structure was used to simulate a simplified barge in the beam sea condition. The structure with a draft one-half of its height was hinged at the center of gravity and free to roll (1 degree of freedom) by waves. The dynamic characteristics of the structure were first identified, including its roll natural period. The dynamic response of the barge-like structure under wave actions was then tested with regular waves with a range of wave periods that are shorter, equal to, and longer than its roll natural period. Particle image velocimetry was used to obtain the velocity field in the vicinity of the structure. The coupled interactions between the incident waves and the structure were demonstrated by examining the vortical flow fields to elucidate the effect of viscous damping (also called the eddy making damping) to the roll motion of the structure over wave periods. For incoming waves with a wave period same as the roll natural period, the structure roll motion was, as expected, greatly reduced by the viscous-damping effect. At wave periods shorter than the roll natural period, the structure roll motion was slightly reduced by the viscous effect. However, at wave periods longer than the roll natural period, the viscous effect due to flow separation at structure corners indeed amplified the roll motion. This indicates that not only can the viscous effect damp out the roll motion, it can also amplify the roll motion.