An automatic stabilizer for the high-speed drill spindle in which when the rotation speed of the drill spindle is in excess of the natural frequency, the vibration centric momentum goes in the opposite direction of the mass imbalance. Further, in the electric drill, when the direction of drilling is displaced in drilling work using the electric drill, it is sensed automatically to stop the drilling. The first and the second compartments have fluid communication with each other, to simulate perfusion between the first and the second compartments. The segmentation is preferably accomplished using a graph cutslevel set method to obtain a grid of signed distance function data. The strip is positioned under tension. Once the icon is selected, voice based on the recording time recorded in association with the icon is reproduced to sound the comments, etc.