239 research outputs found
Newton-Euler, Lagrange and Kirchhoff formulations of rigid body dynamics: a unified approach
A unified formulation of rigid body dynamics based on Gauss principle is
proposed. The Lagrange, Kirchhoff and Newton-Euler equations are seen to arise
from different choices of the quasicoordinates in the velocity space. The
group-theoretical aspects of the method are discussed.Comment: 5 page
Diffraction effects in length measurements by laser interferometry
High-accuracy dimensional measurements by laser interferometers require
corrections because of diffraction, which makes the effective fringe-period
different from the wavelength of a plane (or spherical) wave . By
using a combined X-ray and optical interferometer as a tool to investigate
diffraction across a laser beam, we observed wavelength variations as large as
. We show that they originate from the wavefront evolution
under paraxial propagation in the presence of wavefront- and intensity-profile
perturbations.Comment: preprint, 10 pages, 6 figures, submitted to Optics Expres
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