Applications of computer algebra to the theory of electron energy loss

This thesis develops dielectric theory in multilayers and following cases have been considered: - Normal incidence on a multilayered slab with n isotropic layers. - Parallel incidence on a multilayered slab with n isotropic layers. - Normal and parallel incidence on a multilayered with n anisotropic layers, analysed in the non-retarded limit. In each case we have developed the appropriate transfer matrix recurrence relation and solved it exactly, using computer algebra (REDUCE and MATHEMATICA) as an essential guide. For all the problems listed above, we have obtained closed form solutions for the dispersion relations of surface and interface plasmons and for the angle-resolved energy-loss function. The energyloss spectrum is then obtained by integrating over wavevectors. The formulas we have derived are applied to real materials such as Al/Mg, Al/Al2O3, Al/SiO2/Si, diamond and graphite

Ghost imaging lidar via sparsity constraints

For remote sensing, high-resolution imaging techniques are helpful to catch more characteristic information of the target. We extend pseudo-thermal light ghost imaging to the area of remote imaging and propose a ghost imaging lidar system. For the first time, we demonstrate experimentally that the real-space image of a target at about 1.0 km range with 20 mm resolution is achieved by ghost imaging via sparsity constraints (GISC) technique. The characters of GISC technique compared to the existing lidar systems are also discussed.Comment: 4pages, 3figure

A Novel Web Page Filtering System by Combining Texts and Images

With the rapid development of the Internet, people benefit much from the sharing of information. Meanwhile, the WWW era is a double-edged sword which spreads harmful and erotic content widely. In this paper, a new statistical approach has been exploited by combining the results of two or more different classification methods using our filtering system. We first briefly introduce the classification of discrete texts, continuous texts and images separately, and then describe the specific way we have been exploring to merge the text and image classification result. Also there is a section illustrating our system framework. Finally we assess our method by demon-strating the experimental results and comparing it to some common-used filtering methods

Shared Values and Normal Families of Meromorphic Functions

AbstractIn this paper, we study the normality of a family of meromorphic functions concerning shared values and prove the following theorem: Let F be a family of meromorphic functions in a domain D, let k≥2 be a positive integer, and let a, b, c be complex numbers such that a≠b. If, for each f∈F, f and f(k) share a and b in D, and the zeros of f(z)−c are of multiplicity ≥k+1, then F is normal in D