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1.
本文简要评述了中能重离子碰撞中可能存在的奇异密度分布形成-气泡核和环形核的形成,并论述了实验观测方面的可能特征。  相似文献   

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在质量区A<70范围内,对远离β稳定线的缺中子核质子衰变的可能性进行了理论预言,计算基于Kelson-Garvey核力电荷对称质量关系和同位旋相似态质量公式,给出了预言的核素图,将预言计算与实验结果进行了比较,对绝大多数已发现的核,质子能量在300keV以内符合得很好.计算同时指出双质子、三质子衰变的可能性,并给出了目标核.  相似文献   

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奇异核漫谈     
 一八九六年放射性现象的发观,使人类第一次接收到来自原子核的信息.十五年以后,原子的有核模型出现了.到了一九三二年,发现了中子,这促使人们认识到原子核是由不带电的中子和带正电的质子所组成.在核物理与核化学中,把由一定数目的质子与中子组成的原子核称为一种核素.至今已发现的核素约有二千七百种,其中仅有二百八十种左右是稳定的,也就是说,人们没有发现它们通过放射性衰变而转化为另一种核素的现象.  相似文献   

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分析了20 < A < 190范围内丰中子核β衰变的实验数据,根据半衰期随质子数、中子数以及衰变能变化所呈现的壳效应和对效应等特点,提出了一种有效估算丰中子核β衰变寿命的公式。新的计算公式形式简单包含了较少的参数、计算量小。用该公式能较为准确地再现丰中子核的β衰变半衰期。用RIKEN最新测量丰中子核半衰期检验了该公式的外推能力,本工作可以为r-过程研究提供可靠的输入数据。Experimental data of the β--decay half-lives for the nuclei with atomic number between 20 and 190 are investigated. We have systematically studied the shell effects and pairing effects on β--decay half-lives versus the decay energy Q and nucleon numbers (Z, N). An empirical formula has been proposed to calculate the β--decay half-lives of neutron-rich nuclei. The empirical formula is simple and has relatively few parameters. Experimental β--decay half-lives of the neutron-rich nuclei are well reproduced by the new formula. In addition, the extrapolating capacity of this formula has been checked with the very recent experimental data from RIKEN. The predicted half-lives for r-process relevant nuclei with the current formula can be served as the reliable input of r-process model calculations.  相似文献   

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简要介绍了核结构和衰变数据评价国际协作网的组建,中国小组评价活动,历届会议简况,以及第11届会议取得的主要成果。  相似文献   

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系统地研究了相对论夸克模型框架下的底奇异介子的辐射衰变。给出了底奇异介子E1 和M1 辐射衰变分宽度。这些结果表明,大多数电偶极辐射衰变宽带能达到数个keV,大多数磁偶极辐射衰变宽度小于1 个keV,这为实验上通过辐射衰变寻找底奇异介子提供了理论依据。建设中的Belle II 上的实验可以进一步验证我们的结果。We systematically study the radiative transitions of bottom-strange mesons in the framework of the relativistic constituent quark model. The partial widths of the E1 and M1 decays are predicted. The results predict that most of E1 decay widths are several keV and most of M1 decay widths are less than 1 keV,which give a roadmap of searching for the higher bottom-strange mesons via radiative decays. The experimental searches by the forthcoming Belle II can in turn provide further tests to our result in the present work.  相似文献   

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简单介绍了近年来在超重核研究方面所取得的成就和理论方面所面临的挑战.着重介绍推广的液滴模型和准分子形状机制,它们的优点是考虑了精确的核半经、质量和电荷的不对称性、形变、亲和力和温度等.推广的液滴模型和准分子形状机制能很好地描述重核和超重核的裂变、衰变及完全熔合反应.The progress and challenge on studies of superheavy elements both experiments and theories has been briefly introduced. It is emphasis to introduce a generalized liquid drop model, including the proximity effects, the asymmetry, an accurate nuclear radius, and quasi molecular shapes. The α decay half lives of 373 nuclei and superheavy elements have been calculated in the generalized liquid drop model and compared with the available experimental data. The deformed energies have also been obtained ...  相似文献   

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本文从原理上分析了采用舍选法进行随机抽样,得到符合放射性衰变统计规律的模拟计数值,并用TC进行了编程实现;然后介绍了利用办公自动化软件中的电子表格EXCEL处理数据的方法;最后根据程序生成的模拟计数进行了处理,获得了理论频数和实验频数的对照图;进一步可以进行x2检验。  相似文献   

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就核衰变数据在活化反应截面评价中的作用和影响作了比较详细的介绍,通过几个实例,说明在活化反应截面评价中必须充分考虑核衰变数据的作用和影响.核衰变数据的不准确性有时是造成活化反应截面彼此间分歧的主要原因.  相似文献   

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A novel method for mass measurements of short-lived exotic nuclides is presented. Exotic nuclides were produced and separated in flight at relativistic energies with the fragment separator (FRS) and were injected into the experimental storage ring (ESR). Operating the ESR in the isochronous mode we performed mass measurements of neutron deficient fragments of 84Kr with half-lives larger than 50 ms. However, this experimental technique is applicable in a half-life range down to a few μs. A mass resolving power of 110000 (FWHM) has been achieved. Results are presented for the masses of 68As, 70,71Se and 73Br. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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Physics of Atomic Nuclei - Processes involving the ionization of atomic shells and x-ray transitions in daughter nuclei and accompanying alpha decay of superheavy isotopes are considered. The...  相似文献   

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在Vlasov框架下讨论了高温、高压缩核物质的动力学演化过程.通过研究得出,初始过程对碎裂的影响很大,这里密度的影响比热激发能的影响更大.在相同的初始条件下,不可压缩系数对碎裂过程影响很大,即热核在硬势的平均场中比在软势的平均场中更易裂开  相似文献   

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A high-sensitive fluorescence cell has been developed with an aim to perform laser spectroscopy of exotic nuclei. This fluorescence cell has been tested off-line for stable isotope 133Cs. Also, an investigation of the nuclear root mean square (r.m.s.) charge and neutron radii, and of the binding energies of the cesium long isotopic chain has been carried out in the relativistic mean field (RMF) and relativistic Hartree–Bogoliubov (RHB) formalisms. The RMF/RHB calculations are compared with the experimental data and are found to be in good agreement.  相似文献   

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介绍了用放射性核束研究奇异核性质的物理问题, 分析了理论研究的主要方法、模型和现状, 并就对关联、连续态与束缚态的耦合、壳效应和自旋 轨道相互作用、质子晕等问题作了进一步的讨论.We briefly present the physical aspects in the study of exotic nuclei with radioaction nuclear beams and introuduce the main theoretical methods,models and present status. A few theoretical problems,such as....  相似文献   

17.
The decay of unstable nuclei which disintegrate with simultaneous emission of few charged fragments is studied. The decay scenario is determined by means of consideration of the Coulomb-correlated quasi-classical motion of outgoing clusters in the sub-barrier region. It is shown that the special solutions which describe the self-similar expansion are particularly important to describe penetration through a multi-dimensional potential barrier. The correlated motion of outgoing particles at the final stage of sub-barrier penetration leads to the energy and angular correlations of emitted particles.  相似文献   

18.
A brief review of theoretical results for the double-beta decay and the double-electron capture in heavy deformed nuclei is presented. The half life of 160Gd is evaluated using an extended version of the pseudo SU(3) model. While the 2 mode is forbidden when the most probable occupations are considered, states with different occupation numbers can be mixed through the pairing interaction. The amount of this mixing is calculated using perturbation theory. The possibility of observing the decay in 160Gd is discussed for both the 2 and 0 modes.  相似文献   

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讨论奇特核和超核中的各种晕现象. 根据密度相关零程对力的相对论连续谱Hartree Bogoliubov理论给出的计算结果, 预言了中子滴线附近的Ca原子核中可能存在着巨晕, 并简要介绍了O, Ni, Zr, Sn和Pb等一些质子幻数核从质子滴线到中子滴线之间的原子核基态性质. 随后给出超核内的晕现象研究, 如Ca超核内的中子晕和153ΛC内的单Λ超子晕. Halos in the relativistic continuum Hartree Bogoliubov (RCHB) theory are investigated,including giant halo in the even N Ca isotope near neutron drip line,halos in hypernuclei and the hyperon halos in 153ΛC.  相似文献   

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