К вопросу о влиянии неоднородного диэлектрического покрытия на характеристики металлической поверхности

Within the framework of the quantum-statistical functional and the Ritz method, the the problem of finding the surface energy per unit area and work function electrons of a metal flat surface with a inhomogeneous dielectric coating, taken into account in the approximation of a continuous medium. For a uniform coating, the calculated values are insensitive to the selection one-parameter functions for an electronic profile, but sensitive to the gradient series of kinetic energy non-interacting electrons. Calculations are performed for Al, Na and the comparison with the calculations by the Kohn-Shem method is made. Analytically the connection between the theory of the Ritz method for inhomogeneous coatings and calculations by the Kohn-Shem method work function of electrons for metal-dielectric nanosandwiches. As it turned out, the influence inhomogeneous coating on the characteristics of the metal surface can be scaled down to a uniform coverage case. The possibility of using the obtained results in various experimental situations are discussed.

Spectral-Reflectance Estimation under Multiple Light Sources

We describe a comprehensive method for estimating the surface-spectral reflectance from the image data of objects acquired under multiple light sources. This study uses the objects made of an inhomogeneous dielectric material with specular highlights. A spectral camera is used as an imaging system. The overall appearance of objects in a scene results from the chromatic factors such as reflectance and illuminant and the shading terms such as surface geometry and position. We first describe the method of estimating the illuminant spectra of multiple light sources based on detecting highlights appearing on object surfaces. The highlight candidates are detected first, and then some appropriate highlight areas are interactively selected among the candidates. Next, we estimate the spectral reflectance from a wide area selected from an object's surface. The color signals observed from the selected area are described using the estimated illuminant spectra, the surfacespectral reflectance, and the shading terms. This estimation utilizes the fact that the definition domains of reflectance and shading terms are different in each other. We develop an iterative algorithm for estimating the reflectance and the shading terms in two steps repeatedly. Finally, the feasibility of the proposed method is confirmed in an experiment using everyday objects under the illumination environment with multiple light sources.

Numerical simulation of characteristics of propagation of symmetric waves in microwave circular shielded waveguide with a radially inhomogeneous dielectric filling

The paper presents a numerical simulation of the propagation characteristics of symmetric E-type and H-type waves in microwave circular shielded waveguide with radially inhomogeneous dielectric filling. Using the modified Galerkin method, the calculation of a circular two-layer shielded waveguide was carried out, as a result of which the distribution of the electromagnetic field of the waveguide with linear and parabolic distribution of permeability was determined. The results obtained using the modified Galerkin method were compared with the results obtained using the classical partial domain method, which agree well enough.

An alternative method for field analysis in inhomogeneous domains

Purpose This paper aims to solve inhomogeneous dielectric problems by matching boundary conditions at the interfaces among homogeneous subdomains. The capabilities of Hilbert transform computations are deeply investigated in the case of limited numbers of samples, and a refined model is presented by means of investigating accuracies in a case study with three subdomains. Design/methodology/approach The accuracies, refined by Richardson extrapolation to zero error, are compared to finite element (FEM) and finite difference methods. The boundary matching procedures can be easily applied to the results of a previous Schwarz–Christoffel (SC) conformal mapping stage in SC + BC procedures, to cope with field singularities or with open boundary problems. Findings The proposed field computations are of general interest both for electrostatic and magnetostatic field analysis and optimization. They can be useful as comparison tools for FEM results or when severe field singularities can impair the accuracies of other methods. Research limitations/implications This static field methodology, of course, can be used to analyse transverse electro magnetic (TEM) or quasi-TEM propagation modes. It is possible that, in some case, these may make a contribution to the analysis of axis symmetrical problems. Originality/value The most relevant result is the possible introduction of SC + BC computations as a standard tool for solving inhomogeneous dielectric field problems.