Positive Q-value neutron transfer mediated sub-barrier fusion reactions are studied with an empirical coupled channels model, which takes into account neutron rearrangement related only to the dynamical matching condi...Positive Q-value neutron transfer mediated sub-barrier fusion reactions are studied with an empirical coupled channels model, which takes into account neutron rearrangement related only to the dynamical matching condition with no free parameters. Fusion cross sections of collision systems ^32S＋^90,94,96Zr are calculated and analyzed. Logarithmic residual enhancement （LRE） is proposed to evaluate the discrepancy between calculated results and experimental data. The experimental data can be described well with this model for the first time as a whole, while the LRE analysis shows that there are still theoretical systematic deviations.展开更多
The fusion dynamic mechanism of heavy ions at energies near the Coulomb barrier is complicated and still not very clear up to now. Accordingly, a self-consistent method based on the CCFULL calculations has been develo...The fusion dynamic mechanism of heavy ions at energies near the Coulomb barrier is complicated and still not very clear up to now. Accordingly, a self-consistent method based on the CCFULL calculations has been developed and applied for an ongoing study of the effect of the positive Q-value neutron transfer （PQNT） channels in this work. The typical experimental fusion data of Ca ＋ Ca and Ni ＋ Ni is analyzed within the unified calculation scheme. The PQNT effect in near-barrier fusion is further confirmed based on the self-consistent analysis and extracted quantitatively.展开更多
The static and energy-dependent nucleus–nucleus potentials are simultaneously used along with the Wong formula for exploration of fusion dynamics of 8^16O＋50^112,116,120Sn reactions. The role of internal structure d...The static and energy-dependent nucleus–nucleus potentials are simultaneously used along with the Wong formula for exploration of fusion dynamics of 8^16O＋50^112,116,120Sn reactions. The role of internal structure degrees of freedom of colliding pairs, such as inelastic surface vibrations, are examined within the context of coupled channel calculations performed using the code CCFULL. Theoretical calculations based on the static Woods–Saxon potential along with the one-dimensional Wong formula fail to address the fusion data of 8^16O＋50^112,116,120Sn reactions.Such discrepancies can be removed if one uses couplings to internal structure degrees of freedom of colliding nuclei.However, the energy-dependent Woods–Saxon potential model（EDWSP model） accurately describes the sub-barrier fusion enhancement of 8^16O＋50^112,116,120Sn reactions. Therefore, in sub-barrier fusion dynamics, energy dependence in the nucleus–nucleus potential governs barrier modification effects in a closely similar way to that of the coupled channel approach.展开更多
The role of positive Q-value neutron transfers in sub-barrier fusion reactions has been studied with a modified quantum coupled channels model with all order couplings（CCFULL model）. Neutron rearrangement related on...The role of positive Q-value neutron transfers in sub-barrier fusion reactions has been studied with a modified quantum coupled channels model with all order couplings（CCFULL model）. Neutron rearrangement related only to the dynamical matching condition with no free parameters is implemented in the model, which provides a way to understand especially the Q-value dependence of sub-barrier fusion reactions. The fusion cross sections of the collision systems 40^Ca＋94,96^Zr have been calculated and analyzed. The general trend of experimental data can be reproduced well with additional channels for neutron rearrangement. We find that enhancement of sub-barrier fusion cross sections is closely related to the Q-value of the transferred neutrons, in particular for channels with sequential even number transferred neutrons.展开更多
A vast body of fusion data has been analyzed for different projectiles and target nuclei. It is indicated that the sub-barrier fusion depends on the fusion Q-value. In terms of a recently introduced fusion Q-value rul...A vast body of fusion data has been analyzed for different projectiles and target nuclei. It is indicated that the sub-barrier fusion depends on the fusion Q-value. In terms of a recently introduced fusion Q-value rule and an energy scaling reduction procedure, the experimental fusion excitation functions are reduced and compared with each other. It is found that the reduced fusion excitations of selected fusion systems show a similar trend. The fusion data for massive nuclei are in agreement with the Q-value rule. In the fusion process, the Q contribution should be considered. Within this approach, the sub-barrier fusion cross sections of most fusion systems can be predicted without involving any structure effects of colliding nuclei. Instances of disagreement are presented in a few fusion systems. The use of the energy scaling as a criterion of possible experimental data inconsistency is discussed. More precise experimental fusion data need to be measured.展开更多
本文介绍了一种基于平面肖特基势垒二极管的440GHz次谐波混频器,采用三维建模提取寄生参数的仿真方法,电路为石英基片悬置微带形式,反向并联二极管对倒置黏贴在基片上。电路中的无源结构以及二极管的线性寄生参数部分利用三维建模并进...本文介绍了一种基于平面肖特基势垒二极管的440GHz次谐波混频器,采用三维建模提取寄生参数的仿真方法,电路为石英基片悬置微带形式,反向并联二极管对倒置黏贴在基片上。电路中的无源结构以及二极管的线性寄生参数部分利用三维建模并进行有限元法分析,最后与二极管的非线性部分联合进行谐波平衡仿真,通过仿真优化获得二极管的最佳嵌入电路。最终,仿真结果显示在3.3m W的本振驱动功率下,射频频率420~460GHz范围内单边带变频损耗低于10d B,在437GHz附近取得最佳值7.3 d B。展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11635003,11025524,11161130520,11175218and U1332207the National Basic Research Program of China under Grant No 2010CB832903the European Commission's 7th Framework Programme(Fp7-PEOPLE-2010-IRSES)under Grant No 269131
文摘Positive Q-value neutron transfer mediated sub-barrier fusion reactions are studied with an empirical coupled channels model, which takes into account neutron rearrangement related only to the dynamical matching condition with no free parameters. Fusion cross sections of collision systems ^32S＋^90,94,96Zr are calculated and analyzed. Logarithmic residual enhancement （LRE） is proposed to evaluate the discrepancy between calculated results and experimental data. The experimental data can be described well with this model for the first time as a whole, while the LRE analysis shows that there are still theoretical systematic deviations.
基金Supported by the National Key Basic Research Development Program of China(2013CB834404)the National Natural Science Foundation of China(11475263,11375268,U1432246 and U1432127)
文摘The fusion dynamic mechanism of heavy ions at energies near the Coulomb barrier is complicated and still not very clear up to now. Accordingly, a self-consistent method based on the CCFULL calculations has been developed and applied for an ongoing study of the effect of the positive Q-value neutron transfer （PQNT） channels in this work. The typical experimental fusion data of Ca ＋ Ca and Ni ＋ Ni is analyzed within the unified calculation scheme. The PQNT effect in near-barrier fusion is further confirmed based on the self-consistent analysis and extracted quantitatively.
基金Supported by Dr.D.S.Kothari Post-Doctoral Fellowship Scheme sponsored by University Grants Commission(UGC)New DelhiIndia
文摘The static and energy-dependent nucleus–nucleus potentials are simultaneously used along with the Wong formula for exploration of fusion dynamics of 8^16O＋50^112,116,120Sn reactions. The role of internal structure degrees of freedom of colliding pairs, such as inelastic surface vibrations, are examined within the context of coupled channel calculations performed using the code CCFULL. Theoretical calculations based on the static Woods–Saxon potential along with the one-dimensional Wong formula fail to address the fusion data of 8^16O＋50^112,116,120Sn reactions.Such discrepancies can be removed if one uses couplings to internal structure degrees of freedom of colliding nuclei.However, the energy-dependent Woods–Saxon potential model（EDWSP model） accurately describes the sub-barrier fusion enhancement of 8^16O＋50^112,116,120Sn reactions. Therefore, in sub-barrier fusion dynamics, energy dependence in the nucleus–nucleus potential governs barrier modification effects in a closely similar way to that of the coupled channel approach.
基金Supported by National Natural Science Foundation of China(11635003,11025524,11161130520,11175218,U1332207)National Basic Research Program of China(2010CB832903)+1 种基金European Commission’s 7th Framework Programme(Fp7-PEOPLE-2010-IRSES)Agreement Project(269131)
文摘The role of positive Q-value neutron transfers in sub-barrier fusion reactions has been studied with a modified quantum coupled channels model with all order couplings（CCFULL model）. Neutron rearrangement related only to the dynamical matching condition with no free parameters is implemented in the model, which provides a way to understand especially the Q-value dependence of sub-barrier fusion reactions. The fusion cross sections of the collision systems 40^Ca＋94,96^Zr have been calculated and analyzed. The general trend of experimental data can be reproduced well with additional channels for neutron rearrangement. We find that enhancement of sub-barrier fusion cross sections is closely related to the Q-value of the transferred neutrons, in particular for channels with sequential even number transferred neutrons.
基金Supported by National Nature Science Foundation of China(11475013,11035007,11175011)State Key Laboratory of Software Development Environment(SKLSDE-2014ZX-08)Fundamental Research Funds for the Central Universities and the Key Laboratory of High Precision Nuclear Spectroscopy,Institute of Modern Physics,Chinese Academy of Sciences
文摘A vast body of fusion data has been analyzed for different projectiles and target nuclei. It is indicated that the sub-barrier fusion depends on the fusion Q-value. In terms of a recently introduced fusion Q-value rule and an energy scaling reduction procedure, the experimental fusion excitation functions are reduced and compared with each other. It is found that the reduced fusion excitations of selected fusion systems show a similar trend. The fusion data for massive nuclei are in agreement with the Q-value rule. In the fusion process, the Q contribution should be considered. Within this approach, the sub-barrier fusion cross sections of most fusion systems can be predicted without involving any structure effects of colliding nuclei. Instances of disagreement are presented in a few fusion systems. The use of the energy scaling as a criterion of possible experimental data inconsistency is discussed. More precise experimental fusion data need to be measured.
文摘本文介绍了一种基于平面肖特基势垒二极管的440GHz次谐波混频器,采用三维建模提取寄生参数的仿真方法,电路为石英基片悬置微带形式,反向并联二极管对倒置黏贴在基片上。电路中的无源结构以及二极管的线性寄生参数部分利用三维建模并进行有限元法分析,最后与二极管的非线性部分联合进行谐波平衡仿真,通过仿真优化获得二极管的最佳嵌入电路。最终,仿真结果显示在3.3m W的本振驱动功率下,射频频率420~460GHz范围内单边带变频损耗低于10d B,在437GHz附近取得最佳值7.3 d B。
