  The present work is a continuations of our previous paper [J.-G. Deng, et
al., Chin. Phys. C, {\bf41}: 124109 (2017)]. In present work, the
$\mathcal{\alpha}$ decay half-life of unknown nucleus $^{296}$Og is predicted
within the two-potential approach and the hindrance factors of all 20 even-even
nuclei in the same region with $^{296}$Og, i.e. proton number $82<Z<126$ and
neutron number $152<N<184$, from $^{250}$Cm to $^{294}$Og are extracted. The
prediction is 1.09 ms within a factor of 5.12. In addition, based on the latest
experimental data, a new set of parameters of $\mathcal{\alpha}$ decay
hindrance factors for the even-even nuclei in this region considering the shell
effect and proton-neutron interaction are obtained.
