According to the above method, the transmission surfaces of {HEAD ~ the first combination} of {TAIL ~ transmission elements} vibrate in a substantially same phase so that the transmission surfaces of the first combination vibrate in an integral manner 
of
According to the above method , the transmission surfaces of { HEAD ~ the first combination } of { TAIL ~ transmission elements } vibrate in a substantially same phase so that the transmission surfaces of the first combination vibrate in an integral manner
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH