Design of Grazing-Incidence Broad-Band Multilayers for Hard X-Ray Reflectors

A new method of designing x-ray supermirrors with broad angular or energy response for use as coatings in x-ray optics is presented. The design is based on an analytical method with oversimplified analytical and semi-empirical formulae, and an extensive numerical method is used in the optimization design. A better initial multilayer is obtained with the former method and optimized with the latter method. In the optimization, a good design is achieved with much less computing time. In addition, the saturation effect due to the interfacial roughness in multilayer also emerges in the design of x-ray supermirrors with definite performances. The reflectivity of C/W x-ray supermirrors as a function of photon energy at the fixed grazing incident angle 0.5°is presented.     

Multi-domain spectral method for modal analysis of optical waveguide

A multi-domain spectral method for scalar optical modal analysis is developed and presented. The method is mesh-free and is applicable to three-dimensional optical waveguide structures that are invariant in one direction. The mode profile is represented as a superposition of one-dimensional preselected basis functions with variable coefficients. As common to spectral methods, the presented method is inherently fast and efficient. Different optical waveguides are analyzed for comparison purpose to exhibit the validity and accuracy of the presented method.     

A method of developing regional road traffic noise management strategies

Road traffic noise management strategies or noise action plans are a necessary tool for pro-active road traffic noise management. A method is proposed for regional scale noise action plans, in part using noise mapping, which is flexible towards various data qualities. A six step method is proposed which links GIS data to road traffic noise calculation methods with the final strategies being presented in GIS format. A ‘Parcel Priority Index’ and a ‘Link Priority Index’ are presented as key variables in the production of regional strategies and planning visions on a road link basis. The noise management strategy method presented is used on a large regional area in South East Queensland, Australia which covers seven local government areas. The results presented indicate the method is successful in prioritising road links equitably for detailed road traffic noise management actions.     

Measurement of moments for centroid estimation in Shack-Hartmann wavefront sensor—a wavelet-based approach and comparison with other methods

A wavelet-based method of moment calculation with a set of basis functions is presented for centroid estimation in a Shack-Hartmann Wavefront Sensor. The method has been compared with other algorithms such as statistical averaging, FFT and least-squares method. A comparative analysis shows that wavelet method has a high accuracy and processing speed, and better suited for wavefront reconstruction applications. Further, the wavelet method presented here has a variable accuracy and resolution, and can be optimized for a particular application under consideration.     

A level-set continuum method for two-phase flows with insoluble surfactant

A level-set continuum surface force method is presented to compute two-phase flows with insoluble surfactant. Our method recasts the Navier–Stokes equations for a two-phase flow with insoluble surfactant as “one-fluid” formulation. Interfacial transport and interfacial jump conditions are treated using the level-set method and the discrete Dirac function. Based on the density-weighted projection method, a stable semi-implicit scheme is used to decouple the velocity components in solving the regularized Navier–Stokes equations. It allows numerical simulations for a wide range of viscosity ratios and density ratios.Numerical simulations on single drop deformation in a 2D shear flow are presented. Simulations on two drop interaction shows that surfactants can play a critical role in preventing drop coalescence. A fully 3D simulation demonstrating the physical interactions of multiple surfactant-laden drops is presented.     

Adaptive edge detection method for images

The novel two-dimensional (2D) wavelet with anisotropic property and application of it has been presented. Wavelet is constructed in the polar coordinate system to obtain anisotropic properties. A novel edge detection method has been developed with the aid of this wavelet. This method detects gradient jump and than follows along this jump. In this way the number of calculation for edge localization is reduced. Moreover, the presented method is able to detect all edges in an image in multi-scale together with its spatial orientation. Proposed wavelet as well as edge extraction method seems to be new way to edge detection for an image.     

基于MOF界面重构的多物质ALE方法

提出一种基于MOF(Moment-of-Fluid)界面重构的多物质ALE(Arbitrary Lagrangian-Eulerian)方法.流体力学方程组采用相容有限元方法进行空间离散.提出一种新的二维子网格力学模型,用来计算混合网格中的物理量经过一个拉氏步后发生的变化,混合网格内的界面重构采用MOF方法.提出一种精确积分守恒重映方法.给出数值算例,如空气和水的Riemann问题,Dukowicz问题,水中强激波与空气泡相互作用问题等.结果表明,方法具有较高的精度,能够处理物质界面和网格的大变形问题.     

一种改进的快速Mini-Norm算法

Ｋｕｍａｒｅｓａｎ和Ｔｕｆｔｓ提出的Ｍｉｎｉ－Ｎｏｒｍ算法通过对空间协方差矩阵进行特征分解，随后构造噪声子空间向量来求解方位。     

Study of the Leakage Loss in a Silica-on-Silicon Slab Waveguide

A simple and efficient method for studying the leakage loss in a conventional silica-on-silicon planar waveguide is presented. The magnitude of the leakage loss is obtained by calculating the complex propagation constant of the leaky waveguide structure. The dependence of the leakage loss on the thickness of the silica buffer layer (as well as the thickness of the silica upper-cladding layer) is investigated. Numerical results are presented and compared to those calculated with the beam propagation method.     

New method for detection of multipaction

A new global method for unambiguous detection of multipaction in microwave communication systems is presented. Theory as well as experiments demonstrate the potential and usefulness of the method. A short review of existing methods for multipaction detection is given as a background, in order to illustrate the advantages of the new method.     

三角形银纳米柱阵列传感乙醇气体方法研究

提出了一种基于金属纳米结构局域表面等离子体共振光谱的有机气体的传感方法.通过时域有限差分法设计了一种具有较高折射率灵敏度的三角形纳米柱阵列,并利用纳米球光刻法进行了制作.对乙醇蒸汽的传感实验结果证明,所制作的三角形银纳米柱对乙醇分子浓度非常敏感,其探测灵敏度达到24ppm/nm.该金属纳米结构传感有机气体的方法有望应用于环境监测等方面.     

Aeroacoustic sound generation in simple expansion chambers

A method is presented for measuring the aeroacoustic source strength in ducts with flow at frequencies at which the wave motion can be considered substantially one-dimensional. The method is based on coherent power flux measurements using pairs of microphones positioned both upstream and downstream of the source region. The method is applied to a flow excited expansion chamber with aeroacoustic source measurements presented for chambers with a range of flow velocities and chamber lengths. The results indicate locked-on flow tones are generated in the chamber. The frequency of these locked-on flow tones is compared with that predicted using describing function theory applied to resonators with a grazing flow as well as that of other literature.     

Semi-implicit magnetohydrodynamic calculations

A semi-implicit algorithm for the solution of the nonlinear, three-dimensional, resistive MHD equations in cylindrical geometry is presented. The specific model assumes uniform density and pressure, although this is not a restriction of the method. The spatial approximation employs finite differences in the radial coordinate, and the pseudo-spectral algorithm in the periodic poloidal and axial coordinates. A leapfrog algorithm is used to advance wave-like terms; advective terms are treated with a simple predictor-corrector method. The semi-implicit term is introduced as a simple modification to the momentum equation. Dissipation is treated implicitly. The resulting algorithm is unconditionally stable with respect to normal modes. A general discussion of the semi-implicit method is given, and specific forms of the semi-implicit operator are compared in physically relevant test cases. Long-time simulations are presented.     

A numerical technique for solving the coupled radiative transfer and heat equations in a random medium with plane geometry

A Monte Carlo based numerical method is presented which generates statistical information equivalent to the unknown flux density solution of the radiative transfer equation within a plane geometry, for a useful class of problems. This method scores all vectorial intersections of randomly generated light paths with a set of internal data surfaces spanning the random medium. This approach has not been previously considered, but can be implemented on a simple and compact computer code that is straightforward to utilize and adapt. The method is presented as an alternative or complement to standard numerical methods and is tested with diffusion theory. Many useful computations can be performed within several minutes. It is particularly well suited to modelling laser-generated heat sources within finite, artificial or biological random media. A numerical solution of the heat equation is then possible on the same set of data surfaces used in the optical model. Illustrative calculations are presented.     

Multibeam X-ray lithography to form deep regular microstructures

A method for the fabrication of regular microstructures with a high aspect ratio (for example, X-ray gratings) by direct multibeam vector recording in layers of an SU-8 resist is presented. An X-ray beam with a wavelength from 0.4 to 1.7 Å is used for recording. The features of the method are described. The fabricated samples of regular microstructures of the SU-8 resist and gold-plated X-ray masks are presented as finished products.     

天体光谱信号的连续谱归一化新方法

采用事先扣除强谱线的策略,提出小波变换与样条拟合相结合的方法进行连续谱拟合,并通过对实际光谱的试验,与较常用的连续谱拟合方法进行比较,结果表明文章提出的方法有明显的优越性。另外,针对多项式拟合等方法得到的连续谱可能会出现负值的情况,推导出有效的连续谱校正公式。     

Vibrations of nearly annular and circular plates

A general procedure is presented to determine the natural frequencies and mode shapes of nearly annular and circular plates. A straightforward perturbation procedure is used with a transfer of the boundary conditions to obtain solutions given by simple expressions. As well as yielding good accuracy quantitatively, the method accurately predicts qualitative behavior. Numerical results are presented for clamped elliptical and square plates.     

Combining the complex variable reproducing kernel particle method and the finite element method for solving transient heat conduction problems

In this paper, the complex variable reproducing kernel particle (CVRKP) method and the finite element (FE) method are combined as the CVRKP-FE method to solve transient heat conduction problems. The CVRKP-FE method not only conveniently imposes the essential boundary conditions, but also exploits the advantages of the individual methods while avoiding their disadvantages, then the computational efficiency is higher. A hybrid approximation function is applied to combine the CVRKP method with the FE method, and the traditional difference method for two-point boundary value problems is selected as the time discretization scheme. The corresponding formulations of the CVRKP-FE method are presented in detail. Several selected numerical examples of the transient heat conduction problems are presented to illustrate the performance of the CVRKP-FE method.     

Relativistische Verallgemeinerung des „modifizierten APW-Verfahrens“

A relativistic generalization of the “modified augmented-plane-wave method” is presented. It permits application to the exact Dirac Hamiltonian as well as to approximated two-component Hamiltonians. The method produces spinors which are everywhere continuous with continuous derivates which is particularly important for the relativistic case.     

非线性薄膜波导TE模色散特性的多层分割法计算

对于芯区为非线性介质、衬底及包层为线性介质的平板波导、提出用多层分割法分析芯区的模场,采用递推公式（等效于推广的传递矩阵法）求解传播常数与光功率间的依赖关系,该法适用地克尔型或非克尔型介质及芯区折射率非均匀的一般情形,实例计算结果与已有的精确数值计算结果十分符合。