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Title

Α. Υπολογισμοί συνολικής ενέργειας των στερεών με την APW μέθοδο. Β. Διάδοση κλασσικών κυμάτων σε σύνθετα περιοδικά υλικά

Alternative Title

Α. Total energy calculations of solids using the apw method. B. Classical waves propagation in periodic composite materials

Author

Σιγάλας, Μιχαήλ Μ

Thesis advisor

Οικονόμου, Ελευθέριος

Abstract

A. Using the APW method, we calculate the band structure and the total energies of alkalies and transition metals in both fcc and bcc structures. The resulting equilibrium lattice constants and bulk modulus are in good agreement with experiment. Also, the results for alkalies suggest certain structural changes. B. The existence of frequency gaps in the spectrum of classical {electromagnetic (EM), acoustic (AC), elastic (EL)} waves propagating in periodic composite materials may have potential applications such as design of filters, antennas, switches, e.t.c. We studied periodic materials consisting of spheres embedded in a host material. For EM waves, gaps appear only in diamond structure. In contract, for AC waves, propagating in fluids, gaps appear in all the structures and the ratio of the parameters between the spheres and the host material are small. Finally, for EL waves, gaps appear in all the structures but for much greater ratios of parameters.

Language

Greek

Issue date

1991-10-01

Collection

School/Department--School of Sciences and Engineering--Department of Physics--Doctoral theses

Type of Work--Doctoral theses

Permanent Link

https://elocus.lib.uoc.gr//dlib/4/1/8/metadata-dlib-1991DIS0160.tkl

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