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α-clustering effect on flows of direct photons in heavy-ion collisions 被引量:6
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作者 Chen-Zhong Shi Yu-Gang Ma 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2021年第6期122-132,共11页
In this study,we reconstruct theγ-photon energy spectrum,which is in good agreement with the experimental data of ^(86)Kr+^(12)C at E/A=44 Me V within the framework of the modified EQMD model.The directed and ellipti... In this study,we reconstruct theγ-photon energy spectrum,which is in good agreement with the experimental data of ^(86)Kr+^(12)C at E/A=44 Me V within the framework of the modified EQMD model.The directed and elliptic flows of free protons and direct photons were investigated by considering theα-clustering structure of ^(12)C.Compared with free protons,direct photon flows provide clearer information about the early stage of a nuclear reaction.The difference in the collective flows between different configurations of ^(12)C is observed in this study.This indicates that the collective flows of direct photons are sensitive to the initial configuration.Therefore,theγbremsstrahlung process might be taken as an alternative probe to investigate theα-clustering structure in a light nucleus from heavy-ion collisions within the Fermienergy region. 展开更多
关键词 Nuclear reaction Direct photon Collective flow α-clustering configuration
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CEA:基于弱势种群保护抗早熟的聚类淘汰算法 被引量:1
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作者 向剑平 唐常杰 +2 位作者 陈瑜 王悦 杨宁 《四川大学学报(工程科学版)》 EI CAS CSCD 北大核心 2009年第5期146-150,共5页
传统基因表达式编程算法(GEP)决定个体遗传权时过分依赖适应度,忽略了个体间相互关系,造成GEP算法易早熟而影响进化效率。为克服该问题,从理论上研究了造成GEP早熟的原因,并根据研究结果提出弱势种群保护抗早熟的聚类淘汰算法CEA(cluste... 传统基因表达式编程算法(GEP)决定个体遗传权时过分依赖适应度,忽略了个体间相互关系,造成GEP算法易早熟而影响进化效率。为克服该问题,从理论上研究了造成GEP早熟的原因,并根据研究结果提出弱势种群保护抗早熟的聚类淘汰算法CEA(cluster-elutriate Algorithm);定义β-cluster及相关概念;用种群所含不同簇的数量来度量种群的多样性达到保护弱势种群。利用概率手段详细分析了个体参与下一代的机率。实验表明,基于CEA的算法能很好的防止GEP函数发现时的早熟现象,且极大地提高了函数发现效率。 展开更多
关键词 CEA算法 最远临近聚类 β-cluster 个体适应度相似
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Emission time sequence of neutrons and protons as probes ofα-clustering structure 被引量:1
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作者 黄勃松 马余刚 《Chinese Physics C》 SCIE CAS CSCD 2020年第9期122-129,共8页
Neutron-proton momentum correlation functions are constructed from a three-body photodisintegration channel,i.e.,core+n+p,and used to explore the spatial-time information of the non-clustering Woods-Saxon spherical st... Neutron-proton momentum correlation functions are constructed from a three-body photodisintegration channel,i.e.,core+n+p,and used to explore the spatial-time information of the non-clustering Woods-Saxon spherical structure as well as theα-clustering structures of^12C or^16O based on an extended quantum molecular dynamics model.The emission time sequence of neutrons and protons is indicated by the ratio of velocity-gated neutron-proton correlation functions,demonstrating its sensitivity toα-clustering structures.This work sheds light on a new probe forα-clustering structures. 展开更多
关键词 photonuclear reaction neutron-proton correlation α-clustering nuclei
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α-cluster structure of ^(12)C and ^(16)O in the covariant density functional theory with a shell-model-like approach 被引量:2
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作者 刘朗 赵鹏巍 《Chinese Physics C》 SCIE CAS CSCD 2012年第9期818-822,共5页
The α-cluster structures for 12^C and 16^O are investigated in the framework of the covariant density functional theory, where the pairing correlation is treated with a particle number conserving shell-model-like app... The α-cluster structures for 12^C and 16^O are investigated in the framework of the covariant density functional theory, where the pairing correlation is treated with a particle number conserving shell-model-like approach. The ground states of 12^C and 160 have been calculated and the density distributions demonstrate an equilateral triangle 3α clustering for 12^C and a regular tetrahedron 4α clustering for 16^O The existence of linear nα chain structure of both 12^C and 16^O is revealed at high quadrupole deformation. 展开更多
关键词 pairing correlation α-cluster covariant density functional theory shell-model-like approach
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Three-alpha structure of ^(12)C and symmetry 被引量:1
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作者 解文方 鲍诚光 《Science China Mathematics》 SCIE 1997年第4期436-440,共5页
The important features of the low-lying states of C are obtained via an analysis of quantum mechanical symmetry. The existence of a 4 state lower than the 4] state is found to be essential to judging the validity of t... The important features of the low-lying states of C are obtained via an analysis of quantum mechanical symmetry. The existence of a 4 state lower than the 4] state is found to be essential to judging the validity of the Set model of 12C. It is pointed out that the states can be candidates of the linear chain structure. 展开更多
关键词 QUANTUM mechanical SYMMETRY α-cluster model linear CHAIN structure.
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New microscopic wave function of α-condensation 被引量:1
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作者 Akihiro TOHSAKI 《Frontiers of physics》 SCIE CSCD 2011年第3期320-336,共17页
We explain how to treat a microscopic wave function of α-condensation taking a 3α-nucleus as a typical example. The wave function has been originally proposed ten years before by Horiuehi, Ropke, Schuck and the pres... We explain how to treat a microscopic wave function of α-condensation taking a 3α-nucleus as a typical example. The wave function has been originally proposed ten years before by Horiuehi, Ropke, Schuck and the present author (Phys. Rev. Lett., 2001, 87: 192501). The microscopic model, which fully takes into account the Pauli principle between all the constituent nucleons, effective inter- nucleon forces and the Coulomb force, can play an important role in reproducing an α-gas nature thanks to α-condensation as an excited state of α-like nuclei. An essential point of the wave function is to describe their ground state simultaneously. We study its typical features by giving an analytical formula of the norm kernel and the kernel concerning the one-body operator for 3α-condensation. 展开更多
关键词 α-cluster model analytical formula α-condensation
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Structural evolution and zero-field SMM behaviour in ferromagnetically-coupled disk-type Co_(7)clusters bearing exclusively end-on azido bridges
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作者 Yijia Jiao Yuzhu Li +4 位作者 Yuting Zhou Peipei Cen Yi Ding Yan Guo Xiangyu Liu 《Chinese Chemical Letters》 SCIE CAS 2024年第8期567-571,共5页
Concise chemistry leads to a family of heptanuclear Co^(Ⅱ)-clusters,[Co_(7)(N_(3))_(12)(CH_(3)CN)_(12)][Y_(2)(NO_(3))_(4)(piv)_(4)]·2CH_(3)CN(DC1)(pivH=pivalic acid),[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(0... Concise chemistry leads to a family of heptanuclear Co^(Ⅱ)-clusters,[Co_(7)(N_(3))_(12)(CH_(3)CN)_(12)][Y_(2)(NO_(3))_(4)(piv)_(4)]·2CH_(3)CN(DC1)(pivH=pivalic acid),[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(0.4)(Cl)_(1.6)]·4CH_(3)CN(DC2)and[Co_(7)(N_(3))_(12)(CH_(3)CN)_(10)(NO_(3))_(2)]·4CH_(3)CN(DC3),in which the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology.The resulting clusters exhibit interesting structural transformations and thermodynamically-distinct steady states verified by theoretical calcula-tions.Magnetic studies reveal the first observation of zero-field SMM behaviour in disk-like heptanuclear Co^(Ⅱ)complexes. 展开更多
关键词 Multinuclear Co^(Ⅱ)-clusters Disk-like motif Structural modulation Ferromagnetic coupling Zero-field SMM
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