Analysis of Cr Atoms Three-Dimensional Deposition Characteristics
The semi-classical model is used to simulate the three-dimensional trajectory and deposition distribution of the chromium atoms in the Gaussian laser standing wave field using the Runge-Kutta method, and then the three-dimensional deposition stripes are also given, besides, the effects of atomic beam divergence, chromatic aberration and spherical aberration on deposition structure are also analyzed.
Atom-optical properties of a standing-wave light field
The focusing of atoms to nanometer-scale dimensions by a near-resonant standing-wave light field is examined from a particle optics perspective. The classical equation of motion for atoms traveling through the lens formed by a node of the standing wave is derived and converted to a spatial trajectory equation. A paraxial solution is obtained, which results in simple expressions for the focal properties of the lens, useful for estimating its behavior. Aberrations are also discussed, and an exact numerical solution of the trajectory equation is presented. The effects on focal linewidth of angular collimation and velocity spread in the atomic beam are investigated, and it is shown that angular collimation has a much more significant effect than velocity spread, even when the velocity spread is thermal.
Transient nonlinear thermal stability analysis of metro cable under pulse power
The load of metro cable system varies a lot from morning rush hours to the evening closure time. With many trains hopping in the rush hours, the long term and economical short term thermal stability become a big issue as a result of the large difference between thermal time constant and the electrical time constant of cable. Based on a 10kV three-core XLPE metro power cable model, the theoretical thermal capacity was calculated according IEC standard. Then, a Finite Element Method (FEM) was employed to analyze the transient electro-thermal phenomena, taking into account various types of power loss in cable system and the non-linear electrical conductivity of the conductor. Finally, the thermal distribution inside the cable was presented as a function of time, and the maximum thermal capacity was predicted in metro cable.