The optimal focusing arrangement for second-harmonic generation is a compromise between the focal intensity and the depth of focus (confocal parameter) within the crystal. In the absence of birefringence (noncritical phasematching), the fundamental beam should have a circular cross section and a confocal parameter of 0.35 of the crystal’s length.1 Angle-tuned (critical) phase matching causes th...

a new dynamic friction model for modeling of elliptical vibration assisted turning (evat) was developed in this research. the periodic change of the friction force direction is known to be one of the most important causes of this phenomenon. in modeling of machining processes (including the evat process), static coulomb friction model was employed by most of the researchers. because of the peri...

In this paper, numerical simulation for a two-dimensional viscous and incompressible flow past the elliptical airfoil is presented by Random Vortex Blob (RVB). RVB is a numerical technique to solve the incompressible, two-dimensional and unsteady Navier-Stocks equations by converting them to rotational non-primitive formulations. In this method, the velocity vector at a certain point can be cal...

Numerical characterization of animal body forms using elliptical Fourier decomposition may be a useful analytic technique in a variety of marine mammal investigations. Using data collected from the Weddell seal (Leptonychotes weddellii), we describe the method of body form characterization using elliptical Fourier analysis and demonstrated usefulness of the technique in photogrammetric mass-est...

We present a study of the efficiency and optimization of cw second harmonic generation by elliptical Gaussian laser beams. Elliptical focusing slightly improves conversion efficiency and reduces crystal damage risk when heavy walk-off is present. Single-pass measurements of the efficiency for doubling 5 15-nm radiation in beta-barium borate (BBO) agree with theory. Thermal effects, caused by ra...