An apparatus and method for obtaining diffusion weighted magnetic resonance images is described. The system includes a power supply unit, a data-retention-voltage monitor cell for monitoring static noise margin of SRAM, a data loss detector for generating a data loss signal, and a dynamic regulating controller that receives the data loss signal for generating a refresh signal and a switch signal. Left and right side portions of the corrugated sheet are connected to the left and right floor frame members. Thus, infinite object and proximate object can be picked up by the same optical system. The valve plate includes a valve face adapted for sliding rotational engagement with a complementary mating face formed on the cylinder block.