Abstract: Considering the boundary conditions due to the slip effect, the modified Reynolds equation is applied to investigate the dynamical lubrication characteristics of the gas bearing of micro-rotor system in micro-electro-mechanical systems (MEMS), the real pressure distribution in the interior of the bearing, the load carrying capacity and the attitude angle are obtained by using numerical calculation method. The characteristics of micro-lubricated gas journal bearings compared with those obtained from macro infinite short bearing indicate that the slip effect has great impact on the dynamical lubrication characteristics of gas bearing. The macro infinite short bearing model and the bearing model without slip effect will overestimate the load carrying capacity of the gas bearing, particularly in the range of high eccentricity  ( >0.6), i.e., the discrepancy will be larger. When the micro-rotor system runs at high-speed or super high-speed, the pressure and load carrying capacity of the gas bearing can be improved.

Key words: Gas bearing, Micro-electro-mechanical systems (MEMS), Slip effect