{TAIL ~ The apparatus} 1 in which said predetermined potential is between 200 V and {HEAD ~ 600 V} and said alternating potential has an amplitude comprised between 200 V and 600 V peak and a frequency between 100 Hz and 1500 Hz 
{ TAIL ~ The apparatus } 1 in which said predetermined potential is between 200 V and { HEAD ~ 600 V } and said alternating potential has an amplitude comprised between 200 V and 600 V peak and a frequency between 100 Hz and 1500 Hz
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH