The 270-MeV Ni-58 + Pd-102 reaction was used for the first recoil-decay tag
ging measurement with Gamma-sphere coupled to the Fragment Mass Analyzer at
Argonne National Laboratory. Level structures of Yb-155, Lu-156, and Lu-15
7, as well as the excited states associated with the 25/2(-) isomer in Lu-1
55, are identified for the first time. The systematical behavior of the ene
rgy levels is compared with that of neighboring isotones and isotopes. The
attractive interaction between h(11/2) protons and h(9/2) neutrons plays an
important role in the structure of Yb-155 and Lu-155,Lu-156.