Nuclear Physics A最新文献_第5页

Measurement and analysis of excitation function for 16O+89Y at energies 4–7 MeV/nucleon 16O+89Y在4-7 MeV/核子激发函数的测量与分析

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2026-01-10 DOI: 10.1016/j.nuclphysa.2026.123326

Mohd Faizan Khan , Avinash Agarwal , I.A. Rizvi , Anuj Kumar Jashwal , Harsh Vardhan , Munish Kumar , S. Ali , M. Gull , Satyam Gangwar , Kamal Kumar , S. Dutt , A.K. Chaubey

In the last couple of years, fusion processes triggered by heavy ions (HIs) have been a primary focus of study in low-energy nuclear physics. Recent experiments have confirmed that complete fusion (CF) and incomplete fusion (ICF) are the most prevalent modes in heavy ion (HI) interactions at energies above the Coulomb barrier. The purpose of the present work is to exclusively explore and measure the excitation functions (EF) of the evaporation residues (ERs) populated in ¹⁶O +⁸⁹Y systems at energies  ≈  4 - 7 MeV / nucleon. A standard stacked foil activation technique followed by offline γ-ray spectroscopy with a high-resolution HPGe detector has been used. The theoretical predictions obtained from the statistical code have been assigned to scrutinise the experimentally measured EFs. In this present work, xn, pxn, αxn and 2αxn channels are investigated. Whereas, the measured excitation function of ERs populated via some xn (n = 2 and 3) channels has been observed to show a high-energy tail portion deviating from the trends of excitation functions as obtained by the statistical code at higher energies. This signifies the presence of pre-equilibrium (PE) emission for these reaction channels. A noticeable enhancement was observed in the production of reaction residues involving α particle(s) in the exit channels, even at energies close to the Coulomb barrier. This enhancement in the cross-section clearly demonstrates the incomplete fusion of the projectile with the target. The incomplete fusion probability has been calculated to better understand the reaction dynamics. The present findings and analysis of the data for various projectile-target combinations strongly suggest that entrance channel parameters like mass asymmetry (μ_A), Coulomb factor (Z_PZ_T) and the variation in neutron excess in the target nucleus (N-Z) play a significant role in the onset of incomplete fusion.

近年来，重离子（HIs）引发的核聚变过程一直是低能核物理学研究的主要焦点。最近的实验已经证实，完全聚变（CF）和不完全聚变（ICF）是重离子（HI）在库仑势垒以上能量相互作用中最普遍的模式。本工作的目的是专门探索和测量在能量 ≈ 4 - 7 MeV / nucleon的16O +89Y体系中存在的蒸发残基（ERs）的激发函数（EF）。采用了一种标准的叠箔活化技术，然后采用高分辨率HPGe探测器进行脱机γ射线能谱分析。从统计代码中获得的理论预测已被分配用于仔细检查实验测量的电场。本文研究了xn、pxn、αxn和2αxn通道。然而，通过某些xn （n = 2和3）通道填充的er的实测激发函数显示出与统计代码在高能量下获得的激发函数趋势不同的高能尾部。这表明这些反应通道存在预平衡（PE）发射。即使在接近库仑势垒的能量下，在出口通道中涉及α粒子的反应残馀的产生也明显增加。这种增强的横截面清楚地说明了弹丸与目标的不完全融合。为了更好地理解反应动力学，计算了不完全聚变概率。目前的研究结果和对各种射靶组合数据的分析强烈表明，入口通道参数如质量不对称（μA）、库仑因子（ZPZT）和靶核中子剩余量（N-Z）的变化在不完全聚变的发生中起重要作用。

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引用次数: 0

Elastic scattering and inclusive α angular distributions for 6Li+93Nb system around the Coulomb barrier 库仑势垒周围6Li+93Nb体系的弹性散射和包涵α角分布

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-12-01 DOI: 10.1016/j.nuclphysa.2025.123303

Arati Chavan , S. Rathi , K. Mahata , S.K. Pandit , V.V. Parkar , A. Shrivastava , K. Ramachandran , Sangeeta Dhuri , Satbir Kaur , Prasanna M , Vineet Kumar

Elastic scattering and inclusive α particle angular distributions were measured for ⁶Li+⁹³Nb system at lab energies of 24.6 MeV and 34.7 MeV. Optical model analysis of the measured elastic scattering angular distributions were analysed to extract the reaction cross sections. The energy and angle integrated α particle cross sections were determined. The reaction cross sections and the α production cross sections from the present measurement are compared with the available experimental data for ⁶Li projectile on various targets, to study the systematic behaviour. Extracted reaction cross sections from the optical model fits and the measured inclusive α agree very well with the systematic behaviour of reaction cross section and inclusive α production cross sections (due to non-compound nuclear process), respectively.

在实验室能量分别为24.6 MeV和34.7 MeV时，测量了6Li+93Nb体系的弹性散射和包包α粒子角分布。对测量的弹性散射角分布进行光学模型分析，提取反应截面。测定了α粒子的能量和角度积分截面。将测量得到的反应截面和α生成截面与已有的6Li弹丸在不同靶上的实验数据进行了比较，以研究其系统行为。从光学模型中提取的反应截面和测量的包涵α分别与反应截面和包涵α产生截面（由于非复合核过程）的系统行为吻合良好。

引用次数: 0

Nuclear shape transition of Th isotope at fission limits: a fourier shape parametrization approach 裂变极限处Th同位素的核形状跃迁：傅里叶形状参数化方法

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-11-24 DOI: 10.1016/j.nuclphysa.2025.123291

K. Jyothish, M.R. Asmitha, Rhine A.K. Kumar

The deformation energy landscape of ²³²Th nucleus along its fission path is investigated using the Lublin-Strasbourg Drop (LSD) model with the Fourier shape parametrization. The nuclear surface is represented by a truncated Fourier series in terms of collective coordinates associated with elongation (q₂), mass asymmetry (q₃), and neck formation (q₄). This parametrization offers enhanced flexibility in describing fission pathways and the complex shape transitions of the thorium isotope up to the scission point. Studying fission characteristics in actinide nuclei such as ²³²Th is crucial to advance our understanding of nuclear energy production and structure.

利用具有傅里叶形状参数化的卢布林-斯特拉斯堡滴（LSD）模型研究了232Th核沿裂变路径的变形能场。核表面由截断的傅立叶级数表示，其集体坐标与延伸率（q2）、质量不对称（q3）和颈部形成（q4）相关。这种参数化在描述裂变路径和钍同位素到裂变点的复杂形状转变方面提供了增强的灵活性。研究像232Th这样的锕系原子核的裂变特性对于提高我们对核能产生和结构的理解至关重要。

引用次数: 0

Systematics of electric dipole excitations in rare-earth 146−156Sm nuclei 稀土146 ~ 156Sm核中电偶极激发的系统论

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-11-29 DOI: 10.1016/j.nuclphysa.2025.123305

E. Guliyev , H. Quliyev , A.A. Kuliev , A. Jalili

The electric dipole responses of the even-even ^146–156Sm nuclei were studied using translational and Galilean invariant (TGI-) quasi-particle random-phase approximation (QRPA), with the highly fragmented E1 strength being predicted. By comparing these calculations with experimental data for the photon absorption cross section σ_γ, it was shown that the QRPA model can reproduce the shape of the GDR quite well. The excitation energies, transition probabilities, and splitting behaviors of the PDR into K = 0 and K=±1 branches and other properties were also investigated further. Calculations on one-phonon wave functions confirmed that the dipole states below the particle threshold energy have characteristics that are different from those exhibited by the giant dipole resonance. Using this difference, we thereby determined the character of the experimentally observed dipole excitations around 10 MeV and showed that the PDR can reach the 10 MeV region. For the first time, PDR and GDR calculations were performed specifically for the ¹⁴⁶Sm and ¹⁵⁶Sm isotopes, providing new insights into their dipole response characteristics.

利用平移和伽利略不变（TGI-）准粒子随机相位近似（QRPA）研究了偶偶146-156Sm核的电偶极子响应，并预测了高碎片化的E1强度。将这些计算结果与光子吸收截面σγ的实验数据进行比较，表明QRPA模型能较好地再现GDR的形状。进一步研究了PDR的激发能、跃迁概率、K= 0和K=±1分支的分裂行为以及其他性质。单声子波函数的计算证实，低于粒子阈值能量的偶极子态具有不同于巨偶极子共振所表现出的特征。利用这一差异，我们由此确定了实验观测到的偶极激发在10 MeV附近的特征，并表明PDR可以达到10 MeV区域。首次对146Sm和156Sm同位素进行了PDR和GDR计算，为其偶极子响应特性提供了新的见解。

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引用次数: 0

Thermal evolution of shape coexistence in Mo and Ru isotopes Mo和Ru同位素形态共存的热演化

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-12-28 DOI: 10.1016/j.nuclphysa.2025.123321

Mamta Aggarwal , Pranali Parab , A. Jain , G. Saxena

The temperature-driven shape dynamics of isotopic chains of Mo and Ru elements and their impact on decay modes have been investigated in a statistical theoretical framework with macroscopic-microscopic apporach. These isotopes located at the key points in r-process path are known for the rapid structural changes, shape instabilities and shape coexistence that impact the nuclear processes, decay modes and lifetimes. At high temperatures that may exist in stars or in various nuclear reaction processes, these nuclei undergo a variety of shape and deformation changes due to thermal shell quenching effects influencing the decay energies (Q value), and eventually life-time have been studied in detail. Our findings provide insight into the observed shift in the deformation, shapes and coexisting states due to the diminishing nuclear shell effects in hot nuclei, revealing that the structural changes influence the decay processes and significantly in the astrophysically relevant Mo-Ru region especially around A = 100.

本文采用宏观-微观方法，在统计理论框架下研究了Mo和Ru同位素链的温度驱动形状动力学及其对衰变模式的影响。这些同位素位于r-过程路径的关键点，以其快速的结构变化、形状不稳定和形状共存而闻名，这些变化影响着核过程、衰变模式和寿命。在恒星或各种核反应过程中可能存在的高温下，由于热壳淬火效应影响衰变能（Q值），这些原子核发生各种形状和变形变化，最终寿命得到了详细的研究。我们的发现提供了观测到的变形、形状和共存状态的变化，这是由于热核中核壳效应的减弱，揭示了结构的变化影响衰变过程，特别是在天体物理相关的Mo-Ru区域，特别是在A = 100附近。

引用次数: 0

Exploring the effect of entrance channel mass asymmetry in the fission of 197Tl* nucleus 探讨入口通道质量不对称对197Tl*核裂变的影响

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-12-18 DOI: 10.1016/j.nuclphysa.2025.123310

Golda Komalan Satheedas , H. Singh , Kavita Kavita , Mohit Kumar , N. Saneesh , A. Jhingan , P. Sugathan , C. Yadav , R. Kumar , R. Dubey , Abhishek Yadav , Neeraj Kumar , A. Banerjee , Anjali Rani , Kavita Rani , J.R. Acharya , S. Noor , S.K. Duggi

Fission fragment mass ratio distributions have been measured for the reactions ¹⁹F+¹⁷⁸Hf and ¹⁶O + ¹⁸¹Ta, both leading to the same compound nucleus, ¹⁹⁷Tl, at near-Coulomb barrier energies. The measured fission fragment mass width for both these systems does not show any substantial deviation from the statistical model predictions, which indicates the absence of non-compound nuclear reactions like quasi-fission. The measured mass widths of both the reactions at the same excitation energy are comparable within the experimental uncertainty and show a gradual increase with excitation energy. No noticeable influence of effect of entrance channel mass asymmetry on fragment mass distribution in these reactions, which differs from the previously reported entrance channel-dependent variation in average pre-scission neutron multiplicity.

对19F+178Hf和16O + 181Ta反应的裂变碎片质量比分布进行了测量，这两个反应都在近库仑势垒能下生成了相同的化合物核197Tl。这两种体系的裂变碎片质量宽度的测量结果与统计模型的预测没有任何实质性的偏差，这表明不存在像准裂变这样的非复合核反应。在相同激发能下，两种反应的测量质量宽度在实验不确定度范围内具有可比性，且随激发能的增加而逐渐增大。在这些反应中，入口通道质量不对称对碎片质量分布没有明显的影响，这与之前报道的平均裂变前中子多重度随入口通道的变化不同。

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引用次数: 0

Role of various nuclear densities and higher-order deformations on the dynamics of 16O+154Sm fusion reaction 不同核密度和高阶变形对16O+154Sm聚变反应动力学的影响

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-12-22 DOI: 10.1016/j.nuclphysa.2025.123314

M. Bhuyan , Shilpa Rana , Raj Kumar

Understanding the role of nuclear structure in heavy-ion fusion reactions is crucial, especially in the low-energy regime where nuclear shape and density profiles significantly influence the reaction dynamics. In this work, we investigate the

^{16} O +^{154} Sm

fusion reaction as an illustrative case by employing three different nuclear density descriptions, namely the relativistic mean-field (RMF) formalism, the Skyrme-Hartree-Fock (SHF) approach, and the two-parameter Fermi (2pF) formula. These densities are folded with relativistic R3Y and non-relativistic M3Y effective nucleon-nucleon (NN) interactions to obtain six different nuclear potentials. Furthermore, the role of quadrupole β₂ and higher-order hexadecapole β₄ deformations of the target nucleus is included in the calculations of nuclear densities, fusion barrier characteristics, and cross-sections. By comparing barrier heights at different orientations, it is observed that the M3Y interaction provides higher barriers than the R3Y interaction. Among the densities, the 2pF yields the highest fusion barrier, while the SHF yields the lowest. The inclusion of β₂ and β₄ deformations results in strong orientation dependence, modifying the fusion barrier, especially at

θ_{2} = 0^{\circ}

. Further, the inclusion of β₄ deformation of the ¹⁵⁴Sm results in a lowering of the fusion barrier height compared to only β₂ deformation, except for target orientation angles 36^∘ < θ₂ < 72^∘. The highest cross-sections are obtained with SHF densities, followed by RMF densities, whereas the 2pF densities underestimate the experimental data. A better match with the experimental cross-section is achieved when structural effects, such as β₂ and β₄ deformations, are included in the SHF and RMF densities, along with the R3Y NN interaction. These findings underline the importance of incorporating detailed nuclear structure effects for a reliable description of heavy-ion fusion dynamics.

了解核结构在重离子聚变反应中的作用是至关重要的，特别是在低能状态下，核形状和密度分布显著影响反应动力学。本文以16O+154Sm核聚变反应为例，采用三种不同的核密度描述，即相对论平均场（RMF）形式、Skyrme-Hartree-Fock （SHF）方法和双参数费米（2pF）公式。这些密度与相对论性R3Y和非相对论性M3Y有效核子-核子（NN）相互作用折叠，得到6种不同的核势。此外，靶核的四极β2和高阶六极β4变形的作用被包括在核密度、聚变势垒特性和截面的计算中。通过比较不同方向的势垒高度，可以发现M3Y相互作用比R3Y相互作用提供了更高的势垒。在各种密度中，2pF产生的聚变势垒最高，而SHF产生的聚变势垒最低。β2和β4变形的包含导致了强烈的取向依赖性，改变了融合障壁，特别是在θ2=0°时。此外，154Sm的β4变形与仅β2变形相比，导致融合屏障高度降低，但目标定向角除外36° <； θ2 <； 72°。以SHF密度获得的截面最大，其次是RMF密度，而2pF密度低估了实验数据。当SHF和RMF密度中包含β2和β4变形等结构效应以及R3Y - NN相互作用时，可以获得与实验截面更好的匹配。这些发现强调了结合详细的核结构效应对于可靠地描述重离子聚变动力学的重要性。

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引用次数: 0

Possible explanation of F2n/F2p at large x using quantum statistical mechanics 使用量子统计力学对F2n/F2p的可能解释

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-12-01 DOI: 10.1016/j.nuclphysa.2025.123300

C. Bourrely , F. Buccella , W.C. Chang , D. Di Bari , P.H. Frampton , J.C. Peng

The recent accurate measurements of the scattering of electrons off of the mirror nuclei ³H and ³He show with small errors that the neutron to proton ratio

r (x) = F_{2}^{n} (x) / F_{2}^{p} (x)

, approaches a value larger than 1/4 for x → 1. We suggest a possible explanation for this experimental result by studying the consequences of the Pauli exclusion principle for the parton distribution when the ratio is described by quantum statistical mechanics description in terms of three parameters inspired by the quantum statistical approach.

最近对镜像核3H和3He的电子散射的精确测量显示，在很小的误差下，中子质子比r(x)=F2n(x)/F2p(x)接近于1/4，对于x → 1。我们通过研究泡利不相容原理对部分子分布的影响，对这一实验结果提出了一种可能的解释，当比例被量子统计力学描述为受量子统计方法启发的三个参数时。

引用次数: 0

The role of nuclear symmetry energy and neutron skin thickness of 208Pb in controlling the underlying physics of neutron star 核对称能和208Pb的中子蒙皮厚度在中子星基础物理控制中的作用

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-12-17 DOI: 10.1016/j.nuclphysa.2025.123307

Queena, Mukul Kumar, Sunil Kumar, Raj K. Jagota, Shashi K. Dhiman

The nuclear symmetry energy is fundamental in nuclear astrophysics, influencing phenomena from nuclear structure to gravitational collapse and neutron star formation. Both the symmetry energy and its linear density dependence (L), are critical inputs for numerous nuclear physics and astrophysics applications, as they play a key role in determining properties such as neutron skin thickness (Δr_np) and neutron star radius. Recent results from parity-violating electron scattering experiments on ²⁰⁸Pb (PREX-II: The Lead Radius Experiment)) have offered new insights into these fields. Specifically, the PREX-II experiment has provided a neutron skin thickness for ²⁰⁸Pb of

Δ r_{n p} = 0.283 \pm 0.071

fm. This measurement helps to constrain the nuclear symmetry energy in laboratory environments. In this study, we propose several interactions (SRQs) based on relativistic energy density functionals that correspond to different values of Δr_np for ²⁰⁸Pb, as derived from the PREX-II limits. We observe a correlation between Δr_np of ²⁰⁸Pb and L. We compute the equations of state for nucleonic matter under β - equilibrium conditions for proposed interactions. We also discuss in detail the effects of Δr_np and L on nuclear matter and neutron star properties. Additionally, these interactions are utilized to explore the characteristics of rotating neutron stars.

核对称能是核天体物理学的基础，影响着从核结构到引力坍缩和中子星形成的各种现象。对称能和它的线性密度依赖关系(L)都是许多核物理和天体物理应用的关键输入，因为它们在确定中子表皮厚度（Δrnp）和中子星半径等特性方面起着关键作用。最近在208Pb上进行的违反宇称的电子散射实验（PREX-II：铅半径实验）的结果为这些领域提供了新的见解。具体来说，PREX-II实验为208Pb提供了Δrnp=0.283±0.071 fm的中子皮厚。这种测量有助于约束实验环境下的核对称能。在这项研究中，我们提出了几种基于相对论能量密度泛函的相互作用（srq），它们对应于208Pb的不同值Δrnp，这些值来自PREX-II极限。我们观察到208Pb和l的Δrnp之间存在相关性。我们在β -平衡条件下计算了核物质的状态方程。我们还详细讨论了Δrnp和L对核物质和中子星性质的影响。此外，这些相互作用被用来探索旋转中子星的特性。

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引用次数: 0

Accurate prediction of Gamow-Teller beta-decay matrix elements via machine learning: implications for nuclear structure 通过机器学习准确预测伽莫夫-泰勒β衰变矩阵元素：对核结构的影响

IF 2.5 4区物理与天体物理 Q2 PHYSICS, NUCLEAR

Nuclear Physics A

Pub Date : 2026-03-01 Epub Date: 2025-12-20 DOI: 10.1016/j.nuclphysa.2025.123318

Cafer Mert Yeşilkanat , Serkan Akkoyun

Accurate prediction of Gamow-Teller (GT) beta decay matrix elements [

M (G T)

] is essential for elucidating complex nuclear structure phenomena and understanding astrophysical processes. In this study, we employed five advanced machine learning models (Cubist, Support Vector Regression, Extreme Gradient Boosting, Random Forest, and Bayesian Regularized Neural Networks) to predict GT beta decay matrix elements in

s d

-shell nuclei, using experimental data from NNDC/ENSDF, NUBASE2016, and AME2016. This study systematically compared the predictive performance of traditional theoretical approaches (including the USDB, IM-SRG, CCEI, and CEFT) to that of advanced machine learning models trained based on experimental observations. Our primary objective was to determine whether data-driven models could achieve higher predictive accuracy than computationally expensive theoretical models by learning the complex and nonlinear relationships among experimental parameters that reflect nuclear structure and decay dynamics. The results demonstrate that the Cubist model achieves a significantly lower RMSE (0.073 in the full parameter modeling approach and 0.112 in the reduced parameter modeling approach) and high coefficients of determination (R² = 0.901 and 0.919, respectively), thereby outperforming traditional methods. Furthermore, SHapley Additive exPlanations (SHAP) analysis revealed that a minimal set of critical nuclear parameters predominantly governs GT decay dynamics, thereby enhancing model interpretability without compromising predictive accuracy. Complementing these findings, an online calculator was developed to facilitate rapid, high-fidelity predictions of GT matrix elements. Overall, our study demonstrates that a data-driven approach outperforms established theoretical models. More importantly, by identifying the minimal set of physical observables that govern GT transitions, our work provides crucial insights into the underlying physics of nuclear structure and offers a new benchmark for refining future theoretical models and astrophysical calculations.

准确预测Gamow-Teller (GT) β衰变矩阵元素[M(GT)]对于阐明复杂的核结构现象和理解天体物理过程至关重要。在这项研究中，我们使用了五种先进的机器学习模型（Cubist、支持向量回归、极端梯度增强、随机森林和贝叶斯正则化神经网络）来预测sd壳核中的GT β衰变矩阵元素，实验数据来自NNDC/ENSDF、NUBASE2016和AME2016。本研究系统地比较了传统理论方法（包括USDB、IM-SRG、CCEI和CEFT）与基于实验观察训练的先进机器学习模型的预测性能。我们的主要目标是通过学习反映核结构和衰变动力学的实验参数之间的复杂和非线性关系，确定数据驱动模型是否可以比计算昂贵的理论模型获得更高的预测精度。结果表明，立体主义模型的RMSE较低（全参数建模方法为0.073，约参数建模方法为0.112），决定系数较高（R²分别= 0.901和0.919），优于传统方法。此外，SHapley加性解释（SHAP）分析表明，最小的临界核参数集主要控制GT衰变动力学，从而在不影响预测精度的情况下提高模型的可解释性。为了补充这些发现，开发了一个在线计算器，以促进快速、高保真地预测GT矩阵元素。总体而言，我们的研究表明，数据驱动的方法优于已建立的理论模型。更重要的是，通过确定控制GT跃迁的最小物理观测集，我们的工作为核结构的潜在物理提供了至关重要的见解，并为完善未来的理论模型和天体物理计算提供了新的基准。

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引用次数: 0