Weiping Liu

MAXI J1348-630, a low-mass black hole X-ray binary, exhibited a major outburst in early 2019 followed by a weaker reflare before returning to quiescence. We analyze Insight-Hard X-ray Modulation Telescope observations of this reflare over MJD 58637–58691 in the 1–100 keV band, together with radio monitoring, to investigate the disk–corona–jet evolution. The X-ray spectral analysis shows that the disk flux and the total coronal-powered flux, defined as the sum of the direct Comptonized continuum and reflected emission, follow a similar rise–plateau–decay pattern, with the latter dominating the X-ray emission. Our interpolated cross-correlation function analysis reveals no robust evidence for a nonzero lag on day timescales between the radio emission and either the X-ray count rates or the decomposed disk and total coronal-powered fluxes. This result is consistent with close coupling among the truncated disk, hot inner flow/corona, and compact jet on day timescales, while minute-to-hour delays remain unresolved. Compared with the ordered multiwavelength evolution observed during the 2019 main outburst, this distinct timing behavior suggests that the reflare is not merely a fainter repetition of the major event, but may instead reflect renewed activity within a residual hard-state–like inner accretion structure, potentially involving a lower-lying or more horizontally extended corona temporally coupled to the compact jet on day timescales.

The study of nuclear structure has evolved significantly with the exploration of nuclei far from stability, revealing phenomena such as the modification of shell closures, the emergence of halos, and clustering. This review examines direct nuclear reactions as a primary experimental tool for probing these exotic structures and constraining astrophysical reaction rates, with an emphasis on the experimental observables that connect exotic nuclear structure, indirect astrophysical constraints, and modern inverse-kinematics instrumentation. We discuss the theoretical frameworks and experimental applications of elastic and inelastic scattering, transfer reactions, and knockout reactions. Special attention is given to the role of these mechanisms in mapping shell evolution and in characterizing nuclear deformation and α -clustering. Furthermore, the review highlights the intersection of nuclear structure and astrophysics, detailing indirect approaches such as the asymptotic normalization coefficient technique and the Trojan horse method for determining key stellar reaction rates at low energies. Finally, state-of-the-art instrumentation is surveyed, including high-resolution spectrometers, active target time projection chambers, and storage rings, which enable high-precision measurements in inverse kinematics.

Type I X-ray bursts are thermonuclear flashes on the surface of accreting neutron stars, involving hundreds of nuclei and thousands of reactions with larger uncertainties in reaction rates. To investigate the impact of nuclear reaction rate uncertainties on type I X-ray burst nucleosynthesis, comprehensive Monte Carlo simulations were performed with temperature-independent and -dependent variations in reaction rates using the REACLIB and STARLIB libraries, respectively. A total of 1711 ( p , γ ), ( p , α ), ( α , p ), and ( α , γ ) reaction rates are varied simultaneously along with their inverse reactions via detailed balance. For the first time, it has been found that Monte Carlo sampling with larger perturbations to these reaction rates may lead to multipeak abundance distributions for certain isotopes, such as ⁶⁴ Zn and ⁵⁵ Co. These multipeak structures arise not only from coupled reactions but also from single reactions in some cases. Our studies also confirm previously identified key reactions and provide more robust lists that deserve priority consideration in future studies.

Present and future rare isotope accelerator facilities provide new opportunities to explore the structure of unstable nuclei. We report the measurements of the elastic scattering angular distributions of ²¹Na and ²²Na on the doubly magic ⁴⁰Ca above the Coulomb barrier energies, using high-purity post-accelerated ISOL beams from Beijing Radioactive Ion Beam Facility (BRIF). Angular distributions were measured with a silicon detector telescope array, and relative cross sections were determined with a CaF₂ target on Au backing. The data were well reproduced by optical model calculations with Woods–Saxon and USNP potentials, the latter giving better agreement. These results confirm the stable operation and performance of the BRIF ISOL production and post-acceleration system, demonstrate its capability to provide radioactive beams of useful intensity and purity for future investigations of reaction dynamics and astrophysically relevant processes involving proton-rich nuclei, and simultaneously extend proton-rich elastic scattering studies to heavier systems.

This study presents a comprehensive application and validation of a multi-software coupling workflow for the research and development of gaseous detector systems. The integrated workflow includes particle interaction (Geant4/Garfield++), electrostatic field computation (COMSOL), electronic response (LTspice), and digital signal processing (ROOT). Applied to a Frisch-grid ionization chamber (FGIC) developed for the High-Intensity heavy-ion Accelerator Facility (HIAF), the integrated system simulates the entire response chain, including geometric structure modeling, particle source definition and interactions, electric field distribution calculations, electron-ion transport, electronic circuit response, and digital shaping algorithms. The key advantage of this systematically integrated approach lies in its ability to perform waveform-level simulation and validation. As demonstrated by the FGIC case study, the simulated waveforms show a correlation coefficient of 0.9 with measurements, and the energy spectra exhibit a peak position deviation of <0.5%, confirming the high-fidelity physical simulation of gaseous detectors. This methodology provides a tool for optimizing the design of the FGIC and interpreting its experimental data, with general applicability to other gaseous detector development efforts.

核反应率数据库是天体核合成与恒星演化建模的关键输入量, 直接影响各类核天体物理过程的计算精度与物理可信度. 近年来, 高分辨4π探测器阵列、新型气体探测器、γ-带电粒子符合测量等先进实验技术在关键核天体物理反应研究中得到广泛应用; 同时, 锦屏深地核天体物理实验平台等地下低本底设施也取得了一系列重要进展. 这些新的低能区实验测量结果, 相较于传统数据库依赖的经验外推或者理论计算, 为关键核反应天体环境温度区间的热核反应率评估提供了更直接的约束, 也为未来数据库的持续优化提供了新的实验支撑. 本文系统回顾了当前主流核反应率数据库—REACLIB、STARLIB、BRUSLIB等的建库目标、数据结构与典型应用, 梳理了它们在数据库覆盖、拟合方式与误差评价等方面的特征. 这些数据库在推动核反应网络计算标准化进程中发挥了重要作用. 在此基础上, 结合当前核反应率数据库特点, 在元数据存储结构、数据库更新以及人员组织形式等方面提出若干方法, 并强调了前沿实验进展对先进数据库构建的重要性.

GRS 1915+105 has been well studied since its discovery, and is well-known for its complex light curve variability. Using the full currently available Insight-HXMT dataset from July 2017 to June 2023, we make a comprehensive spectral-timing analysis of this source and report four main findings. First, we uncover a QPO frequency rising branch between MJD 58206 and 58230, where the centroid frequency increases from $\sim$2 Hz to $\sim$6 Hz, consistent with a spectral state transition from the hard to intermediate state. This rising branch completes the full QPO frequency evolution cycle when combined with the subsequent frequency decay phase, and had been missed in prior NICER and Insight-HXMT studies. Second, we identify a previously unreported Flare 3 during the obscured state, which shows distinct spectral and timing properties compared to the earlier flares. Third, we detect sub-Hz QPOs (<1 Hz) in all three flares, specifically at $\sim$0.01 Hz in Flare 1 and $\sim$0.2 Hz in both Flares 2 and 3. In particular, the weak $\sim$0.2 Hz signals observed in Flare 3 indicate ongoing coronal activity despite strong obscuration. Finally, a comparison between QPOs above and below 1 Hz suggests distinct origins, with the former likely arising from Lense-Thirring precession of the inner hot flow and the latter from magnetic perturbations driving a failed disk wind. These findings offer new insights into the unique accretion geometry and variability behaviors of GRS 1915+105.