In this paper airflow, nano-and micro-particle motions in an aerodynamic particle beam focusing system consisting of several lenses, a nozzle and the downstream chamber, was studied. A three-dimensional numerical simulation for the system was presented and the compressible airflow and thermal conditions in the aerodynamic lens system were evaluated. Dilute particle concentration was assumed so ...

An axi-symmetric and swirling vortex sheet is investigated as the simplest ow in which there is non-trivial vortex stretching and as a possible setting for studying vortex cancellation and singularity formation. Rayleigh's criterion indicates linear stability of a single sheet but instability for other conngurations of sheets. Due to the simplicity of vortex sheet problems, the linear modes and...

We first present a bidirectional beam propagation method (BiBPM) based on axially symmetric full-vectorial finite element (Axi-FVFEM). The Axi-FVFEM BiBPM is more versatile than previous scalar for axi-symmetric structure. It has potential to offer efficient analysis widely used FEM or difference techniques, especially large scale waveguide such as long periodic An air gap in an and fibre Bragg...

A novel approach is proposed for the attitude stabilization and reorientation of an axi-symmetric spacecraft subject to two gas jet actuators. The approach is based on a new formulation of the attitude kinematics. Abstract| In this paper we consider the problem of attitude stabilization of an axi-symmetric spacecraft using two pairs of gas jet actuators. These actuators provide control torques ...

In this paper, we consider the minimum-time reorientation problem of an axi-symmetric rigid spacecraft with two independent control torques mounted perpendicular to the spacecraft symmetry axis. The objective is to reorient the spacecraft from an initial attitude, with some angular velocity, to a nal attitude with a certain angular velocity in minimum time. All possible control structures, incl...