Method and apparatus for echo cancellation are provided. The present invention also provides process of preparing dosage form compositions and prophylactic andor therapeutic methods of using such dosage form. Even if the number of bits Q of the multipolar magnetic pole track is increased in order to enhance the resolution, the number of magnetic pole tracks does not need to be increased, and higher resolution can therefore be obtained without increasing the axial length. The displacement material reacts with the solution, and copper in the solution is grown as a result of the displacement over the recess of the conductive region.