The invention relates to an apparatus for machining bevel gears in an indexing method and method for machining the pitch of gears, wherein the production-related pitch error is compensated. The method provides a catheter having a distal end, a proximal end, and a longitudinal axis, the distal end having an intradiscal section with at least one energy delivery device. The method of preparing the dispersed solution of the carbon nanotubes can easily produce a dispersed solution of carbon nanotubes without performing a separate chemical treatment. The pressure of the gas so-injected is adjusted based on the attribute so-sensed. According to the present structure, the number of element electrodes required by the semiconductor integrated circuit can be reduced.