Shears mechanism in two-dimensional cranking relativistic mean field approach

Using the new two-dimensional cranking relativistic mean field (RMF) approach, the shears mechanism of magnetic rotation based on configuration πh121/2νh-211/2 in 142Gd is microscopically and self-consistently examined by investigating the aligning angular momenta of the valence nucleons.     

Shears mechanism in two-dimensional cranking relativistic mean field approach

Using the new two-dimensional cranking relativistic mean field (RMF) approach, the shears mechanism of magnetic rotation based on configuration πh²_11/2⊙νh^－2_11/2 in ¹⁴²Gd is microscopically and self-consistently examined by investigating the aligning angular momenta of the valence nucleons.     

Progress on tilted axis cranking covariant density functional theory for nuclear magnetic and antimagnetic rotation

Magnetic rotation and antimagnetic rotation are exotic rotational phenomena observed in weakly deformed or near-spherical nuclei, which are respectively interpreted in terms of the shears mechanism and two shearslike mechanism. Since their observations, magnetic rotation and antimagnetic rotation phenomena have been mainly investigated in the framework of tilted axis cranking based on the pairing plus quadrupole model. For the last decades, the covariant density functional theory and its extension have been proved to be successful in describing series of nuclear ground-states and excited states properties, including the binding energies, radii, single-particle spectra, resonance states, halo phenomena, magnetic moments, magnetic rotation, low-lying excitations, shape phase transitions, collective rotation and vibrations, etc. This review will mainly focus on the tilted axis cranking covariant density functional theory and its application for the magnetic rotation and antimagnetic rotation phenomena.     

Lectin法分析uNK细胞在人妊娠母胎界面的分布变化

通过Lectin法分析uNK细胞在人妊娠早、晚期母胎界面的分布变化。结果发现:(1)在妊娠早期的蜕膜中,uNK细胞主要有两种形式,一种是成熟uNK细胞,细胞体积较大,胞浆和胞膜呈现强烈的棕黄色染色,分布于蜕膜的血管中。另一种是未成熟uNK细胞,细胞体积较小,胞核呈现黄色染色,分布于蜕膜细胞之间。(2)在妊娠早期的绒毛组织中,uNK主要是未成熟uNK,分布于绒毛间质之间。(3)与妊娠早期蜕膜的uNK细胞数相比,至妊娠晚期,蜕膜的uNK细胞数量明显减少(P<0.01)。(4)在妊娠晚期,绒毛组织不表达uNK细胞。结论:uNK细胞主要分布于子宫蜕膜组织,且随着妊娠的进展,其表达数量明显下降。这种时空性的表达变化可能与其在调控滋养层细胞的侵袭、血管重建及免疫耐受方面密切相关。     

Chiral doublet bands and energy-level crossing

Different definitions for chiral doublet bands based on excitation energies, B(E2) and B(M1) respectively are discussed in the triaxial particle rotor model. For the ideal chiral geometry, the selection rules of the electromagnetic transitions in different band definitions are illustrated. It is also shown that the energy-level crossings between chiral doublet bands may occur.     

核能存储及释放的新机制

 1938年,德国科学家奥托·哈恩等人发现铀裂变现象1939年8月2日,爱因斯坦在写给美国总统罗斯福的信中指出铀裂变可能导致新型重要能源的产生和武器的建造,由此导致了1942年美国研制原子弹的“曼哈顿”计划和1945年7月16日在美国新墨西哥州的沙漠里进行的世界上第一颗原子弹试验,从而使得核能成为可供利用的主要能源之一。通常所说的核能包括原子核的裂变能和聚变能。裂变能是重原子核通过裂变而释放的能量而聚变能是由两个轻原子核聚合成一个较重核而释放能量。除了核武器外,裂变能主要用于发电,目前世界的核电已达总电量的16%。     

从简化模型中悟出质点动力学的真谛

从2016年诺贝尔物理奖及费曼物理教育思想受到启发,本文讨论了目前大学物理教学所欠缺的方面:溯本求源和结果推广.以阿特武德机、抛体轨迹、斜面上的非惯性系、桌面上的绳子为例,从简单模型悟出质点动力学的几个要点:对约束方程求导获得变量之间关系;弹道曲线的理想化和无量纲化;非惯性中的等效重力;逆向思维判断系统运动趋势等.     

Exotic Magnetic Rotation in 22F

The rotation structure in exotic neutron-rich nucleus 22F is investigated based on the configuration πd5/2（×）vd5/2s^-1 with the newly developed tilted axis cranking relativistic mean field theory in a fully microscopic and seff- consistent way. The possible existence of magnetic rotation is suggested for ^22F via investigating the spectra, the relation between the rotational frequency and the angular momentum, the electromagnetic transition probabilities B（ M1） and /3（E2） together with the shears mechanism characteristic of magnetic rotation. The effect of the nuclear current is also discussed by comparing the calculation results with and without currents.     

Nuclear Current and Magnetic Rotation

The magnetic rotational bands based on the configuration πh11/2^2 vh11/2^-2 in ^142Gd are investigated with the newly developed tilted axis cranking relativistic mean field （RMF） theory with and without nuclear current. The effect of the nuclear current is discussed by comparing the total Routhians, single particle levels, electromagnetic transition probabilities B（M1） and B（E2） in self-consistent tilted axis cranking RMF caIculation with those obtained without the nuclear current. The nuclear currents are found to play an important role in the magnetic rotation of nuclei.     

基于非对称粒子空穴组态的手征双重带

利用三轴形变的粒子转子模型对基于非对称粒子空穴组态πg–1 9/2 νh11/2和πh–1 11/2 νi13/2等的手征双重带进行了研究.详细分析了转动能谱、角动量随转动频率的变化关系、以及约化跃迁几率B(E2)和B(M1)等性质.发现基于非对称组态的三轴形变原子核也有类似对称组态的手征双重带现象.但它们所对应的最佳三轴形变值从γ=30°变为γ～27°.随着组态中价核子角动量的增加,出现手征双重带的自旋随之增加,简并区间也相应增大