Assuming that the Quantum Chromodynamics(QCD)system reaches a state of thermal equilibrium,based on the universality of critical behavior,by mapping the variables of the three-dimensional Ising model onto the QCD phase plane,we investigate the density distributions of fifth-,seventh-,and ninth-order generalized susceptibilities of the net baryon number on the phase plane,as well as their dependence on the net-baryon chemical potential along the chemical freeze-out line.When only the leading-order critical contribution from the Ising model is considered,approaching the critical point from the low net-baryon chemical potential region,the generalized susceptibilities all exhibit a structure characterized by a negative dip fol-lowed by a positive peak.Upon incorporating the next-leading-order critical contribution,the presence of the negative dip be-comes dependent on the distance to the phase boundary and the scaling parameters corresponding to the critical region.However,the positive peak structure remains consistently present and unaffected by these factors.In comparison to the negat-ive dip,the positive peak structure can be considered a more robust feature indicative of the critical point.
Nuclear mass plays an important role on nuclear structure and nuclear astrophysics.For the exotic nuclei far away from the stability valley,at least three orders of the magnitude for the half lives of emitters might be arisen by hundreds of keV difference of the separation energy given by the nuclear mass.At present,149Lu is the proton emitter with shortest lives dis-covered in experiments.The separation energies of the neighbor undetected nuclei will influence the nucleosynthesis path.To this end,we apply Artificial Neural Network(ANN)model and Bayesian Neural Network(BNN)model to constrain the pro-ton separation energy,and the practice indicates that the two approaches have the overfitting and precision problems respect-ively.In order to improve the precision and mitigate the overfitting problem,based on BNN model,and take the uncertainties of the labels and the ensemble uncertainty of the models into account simultaneously,we develop the BNN-Beihang(BH)model.The uncertainties of 148Lu and 160-161Re predicted by the model decreased to less than 100 keV for the first time.These results will effectively improve the precision of the theoretical predictions to the Lu and Re chain proton emitters' lives.
The deep inelastic collision(DIC)process in the 18O+238 U system at an incident energy of 8.5 MeV/u has been in-vestigated by combining the improved quantum molecular dynamics(ImQMD)model with the GEMINI++statistical decay model.Analysis of the total kinetic energy versus the mass distribution of the reaction products confirms that projectile-like fragments are produced predominantly via the DIC mechanism.In this study,key dynamical observables—including differen-tial cross sections,emission angles,and projectile-target contact times—have been extracted for selected projectile-like iso-topes such as carbon(C),oxygen(O),and fluorine(F).The simulations reveal that the differential cross sections of neutron-rich projectile-like fragments peak sharply in the forward angular region,reaching a maximum near 0°.Furthermore,a system-atic trend is observed:as the neutron-to-proton(N/Z)ratio of the projectile-like products increases,the projectile-target con-tact time becomes longer,while the average emission angle shifts toward smaller values.This behavior originates from the prolonged rotational motion(exceeding 200 fm/c,spanning approximately 90°)of the neck-shaped dinuclear system formed during the collision,which facilitates extensive nucleon exchange.Notably,several multi-nucleon transfer channels—specific-ally,the transfer of 1p+2n,1p+3n,and 1p+4n from the 238U target to the 18O projectile—are characterized by positive Q-val-ues(4.212,3.492,and 5.805 MeV,respectively).These exothermic processes significantly enhance the production probabilit-ies,leading to increased differential cross sections for the 21-23F isotopes.The simulation results agree satisfactorily with available experimental data,validating the reliability of the combined ImQMD+GEMINI++approach for describing such heavy-ion collision dynamics.Our findings elucidate the underlying microscopic dynamics of DIC and provide useful theoret-ical insights for future low-energy nuclear physics experiments,particularly those employing next-generation zero-degree spectrometers designed for the efficient production of secondary beams of exotic nuclei.
Based on neutron thermal scattering theory,a neutron thermal scattering cross-section calculation module(ThermalXS)was developed independently in the advanced evaluated nuclear cross section processing program AXSP.Differ-ent types of neutron thermal scattering cross-sections were calculated using the thermal scattering law files of nuclides such as U,H,and Zr.To verify the reliability of the ThermalXS module for thermal neutron calculations,its results were compared with those obtained from the THERMR module of NJOY2016 program.Compared with the THERMR module,the ThermalXS module employs an adaptive incident energy grid technology,which ensures higher accuracy of thermal scatter-ing cross-sections for metal hydrides.Additionally,it is capable of processing thermal scattering law data incorporating one-phonon corrections.In this study,the variations of the thermal scattering cross-sections of graphite across the ENDF/B-Ⅶ.1,ENDF/B-Ⅷ.0,and ENDF/B-Ⅷ.1 evaluated nuclear data libraries were systematically analyzed and validated against ex-perimental values.The results show that the thermal scattering cross section of graphite in ENDF/B-Ⅷ.1,modified using the one-phonon model,shows better agreement with experimental data compared to the graphite crystal model.The primary reas-on is the elimination of the incoherent approximation in the cross-section calculation.The calculated thermal scattering cross section of reactor graphite in ENDF/B-Ⅷ.1 exhibits a trend of increasing with porosity,yet it remains significantly lower than the experimental data for graphite with porosity.
The feasibility study of 18-month fuel management of 157 core was carried out by using the gadolinium rod optim-ization technique.The Equilibrium Cycle fuel management of gadolinium rod optimization scheme was designed,and the main calculation results of the base scheme and gadolinium rod optimization scheme were given.The results show that the gadolinium rod optimization scheme can meet the design criteria of 18-month refueling cycle operation by rationalizing the ar-rangement of fuel assemblies and burnable poison.In the same cycle length,the average discharge burnup of the core with gadolinium rod optimized fuel management design is higher,the fuel usage cost is less,and the economy is better.
