The properties of γ instability in rapidly rotating even-even132-138 Nd isotopes have been investigated using the pairing-deformation self-consistent total-Routhian-surface calculations in a deformation space of（β2, γ,β4）. It is found that even-even134-138 Nd nuclei exhibit triaxiality in both ground and excited states, even up to high-spin states. The lightest isotope possesses a well-deformed prolate shape without a γ deformation component.The current numerical results are compared with previous calculations and available observables such as quadrupole deformation β2 and the feature of γ-band levels, showing basically a general agreement with the observed trend ofγ correlations（e.g. the pattern of the odd-even energy staggering of the γ band）. The existing differences between theory and experiment are analyzed and discussed briefly.
High-spin yrast structures of even-even superheavy nuclei 254-25SRf are investigated by means of total- Routhian-surface approach in three-dimensional （f12, 7, f14） space. The behavior in the moments of inertia of 256Rf is well reproduced by our calculations, which is attributed to the J15/2 neutron rotation-alignment. The competition between the rotationally aligned ila/2 proton and j15/2 neutron may occur to a large extent in 256Rf. High-spin predictions are also made for its neighboring isotopes 254＇2ssRf, showing that the alignment of the j15/2 neutron pair is more favored than that of the i13/2 proton pair.
Total Routhian surface （TRS） calculations for even-even N = 76 isotones with 54 ≤ Z ≤ 68 have been performed in three-dimensional （β2,γ,β4） deformation space. Calculated results of the equilibrium deformations are presented and compared with other theoretical predictions and available experimental data. The behavior of collective angular momentum shows the neutron rotation-alignment is preferred in the lighter N = 76 isotones, while for the heavier ones the proton alignment is favored. Moreover, multi-pair nucleon alignments and their competition （e.g., in 144Er） are predicted. It is pointed out that these nuclei in the N=76 isotonic chain exhibit triaxiality or γ softness in high-spin states as well as ground states. Based on deformation-energy curves with respect to axial and non-axial quadrupole deformations, the shape instabilities are evaluated in detail and predicted, particularly in γ direction. Such instabilities are also supported by the odd- and even-spin level staggering of the observed γ bands, which is usually used to distinguish between y-rigid and γ-soft asymmetry.
