A device is capable of preventing a door and a user from being damaged by automatically locking the door during a cab tilting of a truck. The operator interface system includes instructions for using the volume of cardiac image data and the viewable image for bi-ventricular pacing planning, atrial fibrillation procedure planning, or atrial flutter procedure planning. By reacting an inorganic acid with the quaternary ammonium hydroxycarboxylate or its mixture, a quaternary ammonium salt of inorganic acid or its mixture is produced.