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在核物理和核天体物理中，约束超出饱和密度的核物质状态方程（EOS）具有至关重要的意义。  相对论~Brueckner-Hartree-Fock（RBHF）理论是一种基于现实核力的非微扰核多体方法，但其当前适用的最高密度范围仅限于约三倍饱和密度 $3\rho_0$ ($\rho_0=0.16\ \text{fm}^{-3}$)，因此需要借助可靠的外推技术扩展至更高密度区域。  本工作采用监督式机器学习方法，在低密度RBHF数据上训练了数千个神经网络。  通过施加热力学稳定性和光滑性约束，我们筛选出~264 个采用~Swish 激活函数的最优模型。  利用这些模型将~EOS 外推至高密度区间，获得了核物质对称能，进而计算了中子星的质量-半径关系和潮汐形变，所得结果与当前天文观测高度吻合。  外推不确定性通过统计系综方法进行量化，得到五倍饱和密度处的对称能~$E_\mathrm{sym}(5\rho_0)=136.0 \pm 52.8$~MeV，压强~$P(5\rho_0)=346.3 \pm 97.4~\mathrm{MeV/fm^3}$，最大中子星质量$M_\mathrm{max}=2.18 \pm 0.18~M_\odot$，以及潮汐形变~$\Lambda_{1.4M_\odot}=532 \pm 34$。  本工作建立了一个通用的数据驱动框架，将第一性原理计算与现代机器学习技术相结合，用于探索纯核子、无相变条件下的高密度外推。

The size distribution of aerosols formed from species released by lead-bismuth eutectic (LBE) is an important input for evaluating particle transport and filtration in nuclear facilities. In this study, PbTe-doped LBE was used as a nonradioactive surrogate system. Outlet particle size distributions were measured using a scanning mobility particle sizer (SMPS) at 400-800 °C and inlet relative humidities (RH in ) of 5%, 40%, and 60%, and interpreted together with characterization of the source-pool surface and downstream deposits. Within the 15-30 min comparison window, the total particle number concentration ranged from approximately 2 × 10⁴ to 9 × 10⁸ cm⁻³, and the geometric mean diameter (GMD) ranged from approximately 27 to 77 nm. At 400-600 °C, increasing temperature under low-and intermediate-humidity conditions increased the number concentration, decreased the GMD, and narrowed the distribution, indicating an enhanced small-particle mode. From 700 to 800 °C, the GMD increased from approximately 29-42 to 60-77 nm at all three humidities, indicating a shift toward larger particles. The direction of the humidity effect on number concentration reversed at the tested temperature of 700 °C: high humidity increased the number concentration by approximately two to four orders of magnitude at 400-600 °C, whereas the ordering became 5% > 40% > 60% RH in at 700 °C. At 800 °C, the number concentrations approached 10⁸ cm⁻³ at all humidities. Increasing the temperature from 500 to 700 °C was accompanied by relative Te depletion at the source-pool surface, relative Te enrichment at the deposit surface, and pronounced flake-like and block-like structures. These observations support downstream migration of Tecontaining species and their contribution to deposit formation. The results identify distinct temperature regimes characterized by enhancement of a small-particle mode and a shift toward larger particles, together with a reversal of the humidity effect between 600 and 700 °C. They provide an experimental basis for selecting condition-specific particle size distributions for transport and filtration models of LBE-related aerosols.

We investigate the rapidity density distributions of identified particles and light nuclei produced in Au+Au collisions at $\sqrt{s_{NN}}$ = 3 GeV, measured by the STAR experiment at the BNL Relativistic Heavy Ion Collider (RHIC), using a fireball model with Boltzmann-Gibbs thermodynamics. The fireball model provides a satisfactory description of the experimental data for identified mesons and baryons across all centrality classes. This overall consistency demonstrates that the fireball model provides a useful phenomenological framework for describing the measured rapidity distributions. However, the description requires species-dependent values of the effective temperature and fireball-shape parameters. While the model reasonably reproduces the rapidity density distributions of deuterons ($d$) produced in central and semi-central collisions, it fails to reproduce their rapidity density distributions in peripheral collisions, as well as those for heavier light nuclei with $A\ge 3$. These results imply that light nuclei produced in high-energy heavy-ion collisions originate from a different particle production mechanism than the identified hadrons.

Whether hexadecapole deformation ($\beta_4$) affects $\alpha$ decay remains controversial: machine-learning studies suggest a strong link to $\alpha$-cluster preformation, whereas empirical formulas find only a marginal effect. We show that this discrepancy originates in the treatment of shell effects. When shell effects are not included explicitly in empirical formulas, the residuals can be absorbed into fitted deformation coefficients, obscuring the genuine $\beta_4$ dependence. Including the inverse Casten factor $C_{pn}$, which accounts for valence proton--neutron correlations relative to the nearest closed shells, and the parent-nucleus deformation $\beta_4^{(p)}$ to the Royer formula reduces the root-mean-square deviation from 0.309 to 0.184 for 192 even--even nuclei. The fitted coefficient of $\beta_4^{(p)}$ is negative: positive deformation shortens the half-life, While negative deformation has the opposite effect. This trend is consistent with enhanced $\alpha$-cluster preformation at locally convex surface regions. In the Pu isotopic chain, where $\beta_4^{(p)}>0$ is pronounced, the original Royer formula overestimates half-lives by up to $\sim\!0.42$~dex, providing a testable signature of this surface-preformation effect. The same correction improves the UDL formula, and global predictions for 1060 even--even nuclei are provided in the Supplemental Material.

Unlike ground-state two-proton (2p) radioactivity, excited-state 2p emission is generally characterized bylarger decay energies and non-zero angular momentum, making it a sensitive probe of the nuclear structure ofextremely proton-rich nuclei. However, reliable theoretical descriptions of excited-state 2p radioactivity halflivesremain challenging. To examine whether the generalized liquid drop model (GLDM) with the improvedproximity energy Prox. 77-Set 13, whose parameters were optimized using ground-state 2p radioactivity data,can be extended to excited-state 2p emission, this work calculates the half-lives of 14O∗, 17Ne∗, 18Ne∗, 29S∗,and 94Ag∗. The present calculations are compared with experimental data and with results from the effectiveliquid drop model (ELDM), the unified fission model (UFM), and the Coulomb and proximity potentialmodel (CPPM). The GLDM results agree well with the available experimental data and with other theoreticalcalculations, supporting the applicability of the GLDM with improved proximity energy to excited-state 2p radioactivity.The dependence of the half-life on the decay energy and angular momentum is also systematicallyinvestigated, providing further insight into the decay properties of exotic proton-rich nuclei.