共查询到15条相似文献,搜索用时 70 毫秒
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叶子飘 《原子与分子物理学报》2002,19(1):112-114
计算表明在太阳核心从R=0至R=0.125R⊙之间,存在三价铍7离子数几乎为零.重新计算的铍7太阳中微子和硼8太阳中微子流量要比标准太阳模型分别降低1.2倍和增加1.2倍. 相似文献
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假定11Li,14Be和17B是由N=2Z核芯和两个外层中子组成的三体系统,核芯-中子和中子-中子间的作用为弱吸引指数势,不足以形成核芯-中子和中子-中子二体束缚态.本文的计算表明,核芯-中子-中子三体系统可形成束缚态,计算结果基本上解释了11Li,14Be,17B的基态能量和异常大核半径的实验结果. 相似文献
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通过对太阳核心3He核反应扩散系统的非线性分析,说明在对流和扩散效应的影响下,系统形成一种新的超临界空间结构,3He的密度总量因此被增大.进一步分析说明,3He可以浓集在太阳核心某个有限的局域内,从而使3He+3He反应速率加快以致在这个区域内可以有高的产能率,但中微子产生率不会增加.
关键词: 相似文献
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最近的研究表明13N的beta衰变对于Ia型超新星爆炸前的电子丰度有着重要的影响.本文在壳模型的基础上,首先计算13N基态到基态以及基态到不同激发态的Gamow-Teller(GT)跃迁强度,并将其与实验数据进行了比较.在理论计算的GT强度基础上,对不同温度和密度天体环境下13N的电子俘获率进行了细致的计算,并重点讨论基态到激发态的GT跃迁对电子俘获率变化的影响.结果表明,考虑基态到激发态的跃迁后,超新星的电子丰度下降,中微子能量损失增大.基态到激发态跃迁对电子俘获率的影响主要由低激发能级贡献.
关键词:
Gamow-Teller跃迁
壳模型
电子俘获
激发态 相似文献
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研究了超强磁场对中子星外壳层核素56Fe,56Co,56Ni,56Mn和56Cr电子俘获过程中微子能量损失的影响.结果表明,就大部分中子星表面的磁场B<1013G,超强磁场对中微子能量损失率的影响很小.对于一些磁场范围为1013—1015G的超磁星,超强磁场可使中微子能量损失率大大降低,甚至超过5个数量级. 相似文献
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LIU Jing-Jing KANG Xiao-Ping HE Zhong HUANG Huai-Ren SHI Huan-Yu HUANG Hong-Chao ZHONG Shan FENG Hao LI Chang-Wei 《中国物理C(英文版)》2011,35(3)
Gaussian modifications of the neutrino energy loss (NEL) by electron capture on the strongly screening nuclides 55Co and 56Ni are investigated. The results show that in strong electron screening (SES),the NEL rates decrease without modifying the Gamow-Teller (G-T) resonance transition. For instance, the NEL rates of 55Co and 56Ni decrease more than two and three orders of magnitude for ρ7 = 5.86, T9≤ 5,Ye = 0.47, △ = 6.3, respectively. In contrast, due to Gaussian modification, the NEL rates increase about two orders of magnitude in SES. Due to SES, the maximum values of the C-factor (in %) on NEL of 55Co, 56Ni are of the order of 99.80%, 99.56% at ρ7 = 5.86 Ye = 0.47 and 99.60%, 99.65% at ρ7 = 106 Ye = 0.43, respectively. 相似文献
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Gaussian modifications of the neutrino energy loss (NEL) by electron capture on the strongly screening nuclides 55Co and 56Ni are investigated. The results show that in strong electron screening (SES), the NEL rates decrease without modifying the Gamow-Teller (G-T) resonance transition. For instance, the NEL rates of 55Co and 56Ni decrease more than two and three orders of magnitude for ρ7=5.86, T9≤5, Ye=0.47, Δ=6.3, respectively. In contrast, due to Gaussian modification, the NEL rates increase about two orders of magnitude in SES. Due to SES, the maximum values of the C-factor (in %) on NEL of 55Co, 56Ni are of the order of 99.80%, 99.56% at ρ7=5.86 Ye=0.47 and 99.60%, 99.65% at ρ7=106 Ye=0.43, respectively. 相似文献
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The electron capture rates of 55Co and 56Ni in the ultra-strong magnetic field at four typical temperature- density points have been calculated using the nuclear shell model and Landan energy levels quantized approximate correction. The results show that the electron capture rates of 55Co and 56Ni are increased greatly in the ultra-strong magnetic field, and even exceed two orders of magnitude in the range from 4.414×10^13G to 2.207×10^27 G. The change rate of electron abundance, ye, of 55Co and 56Ni under the condition of B=4.414×10^15G in the magnetar surrounding has been calculated and discussed, the proportions of ye of 55Co and 56Ni in the total Ye have been reduced by 50 percent in all more than the condition without a magnetic field. 相似文献
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The chemical potential of electrons in a strong magnetic field is investigated. It is shown that the magnetic field has only a slight effect on electron chemical potential when B 〈 10^11 T, but electron chemical potential will decrease greatly when B 〉 10^11 T. The effects of a strong magnetic field on electron capture rates for ^60Fe are discussed, and the result shows that the electron capture sharply decreases because of the strong magnetic field. 相似文献
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The astrophysical S-factor for the reaction 7Be(p, γ)8B up to an energy of 2 MeV (c.m.) and the capture cross section of 7Li(n,γ)8Li up to 1 MeV (c.m.) are calculated using the Direct Capture model (DC). Both calculations are in good agreement with experimental data. 相似文献
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The electron capture rates of~(55)Co and~(56)Ni in the ultra-strong magnetic field at four typical temperaturedensity points have been calculated using the nuclear shell model and Landau energy levels quantized approximate correction.The results show that the electron capture rates of~(55)Co and~(56)Ni are increased greatly in the ultra-strong magnetic field,and even exceed two orders of magnitude in the range from 4.414×10~(13)G to 2.207×l0~(17)G.The change rate of electron abundance,Y_e,of~(55)Co and~(56)Ni under the condition of B=4.414×l0~(15)G in the magnetar surrounding has been calculated and discussed,the proportions of Y_e of~(55)Co and~(56)Ni in the total Y_e have been reduced by 50percent in all more than the condition without a magnetic field. 相似文献
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Effect of strong magnetic field on electron capture of iron group nuclei in crusts of neutron stars
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In this paper electron capture on iron group nuclei in crusts of
neutron stars in a strong magnetic field is investigated. The
results show that the magnetic fields have only a slight effect on
electron capture rates in a range of 10$^{8}-10^{13}$G on surfaces of
most neutron stars, whereas for some magnetars the magnetic fields
range from 10$^{13}$ to 10$^{18}$~G. The electron capture rates of
most iron group nuclei are greatly decreased, reduced by even four
orders of magnitude due to the strong magnetic field. 相似文献