section p-p p-p

compression wave， P-wave

dilatational wave， P-wave

p wave p

primary wave， P-wave

P-wave P

3-D travel-time wave field

S wave travel time

Seismic wave travel time

Time-Time-Time Switching Network TTT

3D P-wave

6-(P-2P-S) parallel robot

6-P-2P-S parallel macro manipulator

charmonium P wave spin singlet 1P 1

contravariant tensor of order p p

covariant tensor of order p p

direct P wave

downgoing P-wave

elastic P-wave