A disk drive including a method for determining an amplitude for signal transmission over an interconnect is disclosed. The tubular member includes a large diameter portion and a small diameter portion therebetween having a step defining an inclined portion. A vessel support block supports respective sample vessels below each reactor device for recieving material from the reactor devices. As the compounds reactive with aldehydes, organic amines, organic amine salts, compounds producing organic amines by the reaction with discharges, organic amines, amide compounds, and compounds having a mercapto group can be used. The terahertz electric field time waveform measured by high-speed sampling with the measurement time window of the pulse period is subjected to time-scale conversion and Fourier transform.