A monochromator with improved focusing properties has been designed and constructed using a novel optical geometry based on the Seya–Namioka concept. The only optical elements used are a spherical grating and a cylindrical mirror mounted in the exit arm within the Rowland circle , retaining the Seya–Namioka scanning simplicity while minimizing reflections. This optical system compensates for th...

In applications such as astrophysics and inertial confine fusion, there are many threedimensional cylindrical-symmetric multi-material problems which are usually simulated by Lagrangian schemes in the two-dimensional cylindrical coordinates. For this type of simulation, a critical issue for the schemes is to keep the spherical symmetry in the cylindrical coordinate system if the original physic...

The elongated shape of linear, worm-like, micelles is among the most common aggregation geometries of amphiphilic molecules in aqueous solutions. The cylindrical body of these uni-dimensional micelles can be regarded as an intermediate packing geometry, of a higher growth dimensionality than that of a spherical micelle and lower than that of a planar bilayer. In all these three canonical struct...

We report on a novel approach to the realization of nematic liquid-crystal (LC) phase correctors to form spherical and cylindrical wave fronts. A LC cell with a distributed reactive electrical impedance was driven by an ac voltage applied to the cell boundary to yield the desired spatial distribution of the refractive index. The two-dimensional function of the phase delay introduced into the li...

Reconstruction of hand-held laser scanner data is used in industry primarily for reverse engineering. Traditionally, scanning and reconstruction are separate steps. The operator of the laser scanner has no feedback from the reconstruction results. On-line reconstruction of the CAD geometry allows for such an immediate feedback. We propose a method for on-line segmentation and reconstruction of ...

A number of heating sources are available for minimally invasive thermal therapy of tumours. The purpose of this work was to compare, theoretically, the heating characteristics of interstitial microwave, laser and ultrasound sources in three tissue sites: breast, brain and liver. Using a numerical method, the heating patterns, temperature profiles and expected volumes of thermal damage were cal...

Approximations of the Sedov self-similar solution for a strong point explosion in a medium with the power-law density distribution ρo ∝ r−m are reviewed and their accuracy are analyzed. Taylor approximation is extended to cases m 6= 0. Two approximations of the solution are presented in the Lagrangian coordinates for spherical, cylindrical and plane geometry. These approximations may be used fo...

We consider the free energy of confinement for a flexible self-avoiding polymer inside a spherical cavity. Accurate numerical calculations allow us to arbitrate between competing scaling predictions. We find that, for moderate confinement, the free energy exhibits a power-law dependence on cavity size that is different from what is observed for planar and cylindrical confinement. At high monome...

We first study the linear stability of an interface between two fluids following the passage of an imploding or exploding shock wave. Assuming incompressible flow between the refracted waves following shock impact, we derive an expression for the asymptotic growth rate for a three-dimensional combination of azimuthal and axial perturbations as a function of the Atwood ratio, the axial and azimu...