25MeV/A 20Ne+20周边碰撞

用QMD方法,对²⁰Ne (25MeV/A)+²⁰Ne系统周边碰撞做了仔细的分析,讨论了它的特征,以及深部非弹碰撞与碎裂的共存和竞争,并探索了中间质量碎片的来源.     

294MeV 20Ne+159Tb反应中出射α粒子的研究

在294MeV Ne束轰击Tb靶的反应中,用ΔE-E望远镜测量了10°—150°发射的α粒子能谱,并用运动源模型拟合了所得的实验能谱,得到与前角度源、中等速度源、熔合蒸发源的有关参数.计算谱很好地复现了实验能谱的形状、峰位信数值,角分布也得到极好的模拟.实验所得的发射α粒子截面为3300mb,运动源模型计算值为3700mb.     

20Ne+12C系统与深光学势下的双α转移效应

基于核分子轨道理论分析了²⁰Ne+¹²C系统所展示的基本特征,并且再现了该系统弹性散射激发函数和角分布,研究结果表明,使用一个深光学势的双α转移效应,是产生这两个系统弹性散射激发函数之间差别的重要原因.     

294MeV 20Ne+159Tb反应发射中等质量碎片的研究

在294MeV ²⁰Ne轰击¹⁵⁹Tb靶的反应中,用△E—E望远镜测量了10°—150°发射的中等质量碎片(290°)这些能谱是钟罩型,峰位接近于出射道的库仑位垒.用运动源模型分析了这些能谱,结果说明这些碎片来自于共同的源—非完全熔合所形成的复合核.用统计模型GEMINI程序拟合了碎片的电荷分布和角分布,计算值和实验值很好的符合证实了中等质量碎片来源于复合核非对称的两体衰变.     

20Ne(14.7,19.2MeV/u)+58Ni反应中类弹碎片与α粒子的关联研究

我们研究了在²⁰Ne(14.7,19.2MeV/u)+⁵⁸Ni的反应中出射的类弹碎片α粒子的符合,发现除了原始激发碎片的相继衰变产生这种符合事件以外,还有一种反应过程导致深度耗散的类弹碎片与前方向α粒子的"非关联"符合,这种过程意味着α粒子在反应初期就从弹核²⁰Ne国飞出,而剩余的¹⁶O继而与靶核进行的一种耗散碰撞,我们称之为"非完全的深部非弹性过程".     

17F和18Ne与质子的弹性散射角分布

采用逆运动学方法对放射性核束¹⁷F和¹⁸Ne与质子进行弹性散射实验,得到了实验测量微分截面.用较准确描述放射性核素性质的CH89参数化的光学势为初始光学势,用扭曲波玻恩近似的理论计算程序DWUCK4和自动参数搜索程序ABOD对实验数据进行光学势参数理论拟合,得到了与实验数据相符合的光学势参数.将得到的光学势参数进行分析,得到了17F和18Ne实势相互作用均方根半径分别为3.239fm和3.317fm.     

80MeV/u 20Ne轰击9Be碎裂产物反应总截面的测量

介绍了用透射法测量中能区²⁰Ne打⁹Be靶碎裂产生的次级束与Si靶作用的核反应总截面的方法,以及实验的探测器布局、实验过程和实验结果.并对理论上预言有奇异结构的核¹²N,¹⁷Ne和¹⁷F的实验结果与其相邻核进行了比较.     

12C(7Li,t)16O和20Ne(d,6Li)16O反应的研究

本文把用于处理重离子引起的单粒子转移反应的Goldfarb-Buttle方法推广到多粒子转移反应。计算了¹²C(⁷Li,t)¹⁶O和²⁰Ne(d,⁶Li)¹⁶O反应,用了¹⁶O的全相干波函数,考虑了某些反冲因素,并将结果与实验作了比较。     

40Ca20是否稳定?

本文计算表明通常认为高稳定的双满壳层核⁴⁰Ca₂₀其实并不稳定。⁴⁰Ca₂₀将可能通过双K层电子俘获的机制而转化为⁴⁰Ar₁₈,其半衰期约为1.2×10³³年。 关键词：     

离化态原子Kα射线移位的规律

本文从理论上对离化态原子的K_α射线所发生的移位作了初步的研究,并总结了K_α射线随离化度和原子序变化的规律。提供了有关的数据图表,这可以用来估算各种离化态原子(原子序Z≤42)的K_α射线移位。最后还讨论了测量移位的K_α射线谱,这可以应用于等离子体的杂质诊断。 关键词：     

20Na的β+延发α粒子测量

利用兰州放射性次级束流线提供的²⁰Na束流,通过²⁰Naβ^{+ 20}Ne→¹⁶O+α过程,测量了²⁰Na的衰变半衰期T_1/2及衰变α粒子能谱.结果表明,除了E_d≥2.688MeV的9条较高激发能级的衰变α粒子外,实验中还观察到衰变能量E_d为0.890和1.054MeV,1.991MeV,2.424和2.457MeV的²⁰Ne低激发能级的3条α谱线.     

Equation of State of 20Ne gas in the temperature-range 27–36 K

The many-body phase shifts for ²⁰Ne gas are calculated for low number densities in the temperature-range 27–36?K, using the Galitskii-Migdal-Feynman formalism. These phase shifts are inserted in the Beth-Uhlenbeck formula to determine the quantum second virial coefficient. This is compared to the classical coefficient as well as to the experimental values and other theoretical results. It is used to investigate the pressure-volume-temperature behavior of the gas and to compute other thermodynamic properties – the Helmholtz free energy, total internal energy, entropy, and specific heat capacity – for a number density of 1×?10²⁷ atoms/m³. Our results show that, in cooling and compressing the system, vapor-liquid condensation always occurs.     

Effects of K4CuNb8O23 on phase structure and electrical properties of K0.5Na0.5NbO3–LiSbO3 lead-free piezoceramics

Dense K₄CuNb₈O₂₃ (KCN) modified 0.948K_0.5Na_0.5NbO₃–0.052LiSbO₃ (KNNLS) ceramics were prepared by conventional solid state reaction method. The effect of addition of K₄CuNb₈O₂₃ liquid phase sintering aid on the phase structure and electrical properties of ceramics was studied. Results showed that K₄CuNb₈O₂₃ induced a perovskite structure transition from coexistence of orthorhombic and tetragonal phases to orthorhombic symmetry. The addition of K₄CuNb₈O₂₃ promoted the sintering of KNNLS ceramics. In particular, the K₄CuNb₈O₂₃ addition to the KNNLS greatly improved the mechanical quality factor Q_m value. The ceramics with x=0.8 sintered at 1090 °C possess the optimum properties (Q_m=192, d₃₃=135 pC/N, tan δ=0.024 and k_p=0.357). These results indicate that the ceramic is a promising candidate for lead-free high-power piezoelectric devices, such as piezoelectric actuators, transformers and filter materials.     

α-decay study of 218Ac and 221Th in 40Ar+186W reaction

In this study,²¹⁸Ac and ²²¹Th nuclides were produced via the heavy-ion induced fusion evaporation reaction ⁴⁰Ar+¹⁸⁶W.Their decay properties were studied with the help of the gas-filled recoil spectrometer SHANS and a digital data acquisition system.The cross section ratio between ²²²Pa and ²¹⁸Ac was extracted experimentally,withmeasured value 0.69(9).Two new possible α decay branches to ²²¹Th are suggested.The valence neutron configurations for the daughter ²¹⁷Ra are discussed in terms of the hindrance factors.     

20 Ne(34 Ne)原子与18 Na2(23 Na2,37 Na2)分子低温下冷碰撞的同位素效应研究

本文用多体刚性椭球模型计算了相对入射能量为190 meV时,氖的同位素原子²⁰Ne,³⁴Ne与钠的同位素分子¹⁸Na₂,²³Na₂,³⁷Na₂ 替代碰撞体系的态态转动激发积分散射截面和总转动激发积分散射截面,在此基础上计算并分析了相互作用势的不同区域对²⁰Ne-¹⁸Na_{2关键词： 多体刚性椭球模型 转动激发积分散射截面 钠同位素分子 椭球等势面}     

14.7MeV/u、19.2MeV/u 20Ne诱发反应中转移和碎裂反应过程的竞争

对于在14.7MeV/u、19.2MeV/u ²⁰Ne+⁵⁸Ni反应中出射的类弹碎片,比较其单举动量分布和与前方向20个塑料闪烁体中带电粒子符合的动量分布,区分来自于碎裂过程和转移反应过程的贡献,并研究随束流能量变化时这两种过程的竞争.     

Resonance states in 16O+16O, 12C+16O, α+16O and α+12C with modified Morse potentials

The resonance states in ¹⁶O+¹⁶O, ¹²C+¹⁶O, α+¹⁶O and α+¹²C are described using modified Morse potential proposed earlier whose success has already been demonstrated in the case of ¹²C+¹²C system. The general validity of such a potential with long range, shallow depth and repulsive soft core determined from the resonance data itself is being examined through the present study of the resonances in the above four systems. In each system, the experimental data of a large number of states have been successfully described with a modified Morse potential. The success points out a common mechanism of the origin of these states, and reaffirms authentically the diatomic-like rotational and vibrational picture of the nuclear molecular resonances proposed previously. The close resemblance between the physics of diatomic molecules and nuclear molecular resonances extending to the level of potential which is Morse type in both the cases — although belong to two different areas of physics — is further strengthened through the present study.      

K2分子23∏g—13∑u+漫射谱强度的碰撞诱导增强效应

用4415.6?CW激光线获得了5730?附近的K₂分子2³∏_g—1³∑_u⁺漫射荧光谱。实验研究了缓冲气体Ar气压强P对漫射谱峰值强度I_diff的碰撞诱导增强效应。用稳态碰撞模型描述了C¹∏_u—2³∏_g间的能量转移过程,推导出了I_diff-P函数关系,对实验数据进行了令人满意的拟合。这种拟合表明:适当变更实验装置,利用本文模型可以得到C¹∏_u—2³∏_g间的能级交叉速率和碰撞诱导转移速率。 关键词：     

On the relation between the effective ferromagnetic resonance linewidth Δfeff and damping parameter αeff in ferromagnetic Fe-Co-Hf-N nanocomposite films

Ferromagnetic Fe-Co-Hf-N nanocomposite films were investigated concerning their microstructure-dependent frequency behaviour. To modify the composition, the films were deposited by reactive RF magnetron sputtering by using three different 6 in. targets with various Hf fractions. The films were post-annealed up to 600 °C in a static magnetic field to induce an in-plane uniaxial anisotropy and to obtain different crystal sizes. Depending on the annealing temperature, high-frequency losses were investigated by considering the full-width at half-maximum (FWHM) Δf_eff of the imaginary part of the frequency-dependent permeability which showed a resonance frequency f_FMR of 2.3 GHz for an in-plane uniaxial anisotropy field H_u of 4 mT. The FWHM in correlation with the damping parameter α_eff is discussed, e.g., in terms of two-magnon scattering. Damping occurs due to film inhomogeneity in magnetisation and uniaxial anisotropy caused by a magnetocrystalline anisotropy H_a and/or non-magnetic phases. This will result in homogenous or even inhomogeneous resonance line broadening if additional and resonance as well as precession frequencies of independent grains arise.