Two or more vibration generators may introduce {HEAD ~ vibrations} with different frequencies into {TAIL ~ the chemical bath liquid} and at different angles 
into
Two or more vibration generators may introduce { HEAD ~ vibrations } with different frequencies into { TAIL ~ the chemical bath liquid } and at different angles
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH