Within the framework of the U<SUB>sdpf</SUB>(16) interacting boson model (IBM), the effects of strong correlations of the dipole (p<SUP>?</SUP>-boson) and the octupole (f<SUP>?</SUP>...Within the framework of the U<SUB>sdpf</SUB>(16) interacting boson model (IBM), the effects of strong correlations of the dipole (p<SUP>?</SUP>-boson) and the octupole (f<SUP>?</SUP>-boson) degree of freedom on the positive-parity states of even-even nuclei in SU(3) limit are discussed. It is shown that configurations of an even number of many p- and f-bosons can not only be incorporated into the usual low-lying collective rotational bands, such as the ground state band, β- and γ-vibrational bands, but also naturally form the rotational bands, etc. These results are similar to that of U<SUB>sdg</SUB>(15)-IBM and in good agreement with the experimental data of the nucleus. Besides, several intraband E2 transition probabilities are given, which are consistent with that of U<SUB>sd</SUB>(6)-IBM.展开更多
Every compressor works in a limited operational range. Surge as one of the sources of this limitation has been studied for many years. In this research, an isolated blade row of compressor rotor is numerically modeled...Every compressor works in a limited operational range. Surge as one of the sources of this limitation has been studied for many years. In this research, an isolated blade row of compressor rotor is numerically modeled and solved. In order to improve operational limit and postpone the surge occurrence, a stepped blade of RAF6E with higher stall angle of attack is used to investigate the near stall flow behavior. In this study, several location of step on blades are tried and the results are compared with the case with no step on blades. It is shown that, as the step moves toward the leading edge of blades, the effect of delay on surge is reduced and even efficiency is also decreased significantly. By moving the step towards the trailing edge, surge is delayed due to the reattachment of flow after the step. Efficiency is also decreased but not in the order of the previous case.展开更多
文摘Within the framework of the U<SUB>sdpf</SUB>(16) interacting boson model (IBM), the effects of strong correlations of the dipole (p<SUP>?</SUP>-boson) and the octupole (f<SUP>?</SUP>-boson) degree of freedom on the positive-parity states of even-even nuclei in SU(3) limit are discussed. It is shown that configurations of an even number of many p- and f-bosons can not only be incorporated into the usual low-lying collective rotational bands, such as the ground state band, β- and γ-vibrational bands, but also naturally form the rotational bands, etc. These results are similar to that of U<SUB>sdg</SUB>(15)-IBM and in good agreement with the experimental data of the nucleus. Besides, several intraband E2 transition probabilities are given, which are consistent with that of U<SUB>sd</SUB>(6)-IBM.
文摘Every compressor works in a limited operational range. Surge as one of the sources of this limitation has been studied for many years. In this research, an isolated blade row of compressor rotor is numerically modeled and solved. In order to improve operational limit and postpone the surge occurrence, a stepped blade of RAF6E with higher stall angle of attack is used to investigate the near stall flow behavior. In this study, several location of step on blades are tried and the results are compared with the case with no step on blades. It is shown that, as the step moves toward the leading edge of blades, the effect of delay on surge is reduced and even efficiency is also decreased significantly. By moving the step towards the trailing edge, surge is delayed due to the reattachment of flow after the step. Efficiency is also decreased but not in the order of the previous case.
