Sumários
X-ray diffraction methods
23 abril 2019, 15:00 • João Luís Maia Figueirinhas
The Laue method, the rotating crystal method and the crystalline powder sample method. Use of the Bragg law in the identification of the type of crystalline lattice in simple base crystals by analysis of diffractograms obtained by the crystalline powder method. Solving application problems.
Crystal lattices in 2 and 3 dimensions
22 abril 2019, 13:00 • João Luís Maia Figueirinhas
The different types of crystalline lattices in 2 and 3 dimensions. Bragg's Law. Miller indexes for the families of crystal lattice plans. Reciprocal lattice. X-ray diffraction by a small crystal, Laue's equations, equivalence with Bragg's law.
Introduction to X-ray diffraction
9 abril 2019, 15:00 • João Luís Maia Figueirinhas
Scattered field E by a free electron. Scattered field E by an atom, classical treatment, scattering factor of the atom. Differences for the classical -and quanto-mechanical treatment of EM radiation scattering by an electron. X-ray scattering by a crystalline structure, crystal lattice and base concepts.
Optical Behavior of the PDLC Cell
8 abril 2019, 13:00 • João Luís Maia Figueirinhas
Determination of the effective differential and total light cross-sections using the Van-Hulst scattering matrix, the anomalous-diffraction approach and the Raleigh-Ganz approximation. Calculation of the Intensity transmitted through the PDLC cell using the Lambert-Beer law and considering simple scattering.
Optical Behavior of the Twisted Nematic Cell
2 abril 2019, 15:00 • João Luís Maia Figueirinhas
Obtaining the scatter plot for an electromagnetic wave with wave vector parallel to the torsion axis. Analysis of the characteristics of the different propagation modes.