库仑程函近似下扭曲因子对散射振幅的影响

在库仑程函近似框架下,引进实参量积分,将能壳上跃迁矩阵元分为靶的结构因子和弹的扭曲因子,导出了非分波扭曲因子的主项表达式和结构因子解析表达式,分析了扭曲因子对电子与类氢离子的非弹性散射角分布的影响 关键词： 库仑程函近似 散射矩阵元 扭曲因子     

库仑玻恩近似下电子与氦离子非弹性散射结构因子的计算与分析

在库仑玻恩近似框架下 ,利用库仑势带有数学参量积分的球谐表达式的形式 ,将散射振幅的跃迁矩阵分解为彼此独立的两部分 :入射扭曲因子和靶结构因子 ,以电子与类氢离子—氦离子在库仑玻恩近似下 1s - 2s激发和 1s - 2 p激发的非弹性散射为例 ,导出了靶结构因子的解析发达式 ,并分析了它对微分散射截面的贡献。     

几何结构因子的计算

把几何结构因子分解成两个因子的乘积，使几何结构因子的计算得到简化。     

自相似时间信息的谱研究

本文以Cantor分维集合为时轴,构想了三种自相似时间信息。理论上以逐代繁衍的眼光看待自相似信息,导出它们的谱结构因子递推公式和谱形状因子递推公式,并给出四组谱图。从谱图的比较和演变,看出结构因子的本底作用和形状因子的调制作用,以及各代之间的竞争现象。此项研究为在另一表象(频域)中进一步认识自相似信息提供一种依据。 关键词：     

衍射扭曲高斯-谢尔模型光束在远场的光谱移动和光谱开关

从部分相干光的传输理论出发,研究了被光阑衍射扭曲高斯-谢尔模型光束远场的光谱变化规律。结果表明,扭曲高斯-谢尔模型光束在远场也会出现光谱移动和光谱开关效应。与衍射高斯-谢尔模型光束情况相比,光谱移动和光谱开关效应不仅与光束空间相关性、截断参量和源光谱谱宽有关,光束的扭曲因子也会对衍射扭曲高斯-谢尔模型光束远场的光谱移动和光谱开关效应产生影响。通过数值计算结果详细讨论了光束扭曲因子影响衍射扭曲高斯-谢尔模型远场光谱的规律。     

LiNbO3电光偏转器的研究

从电光效应出发，对ＬｉＮｂＯ３电光偏转器的基本品质因子进行研究，导出了偏转器的设计公式，用有限差分法计算了四柱面电极电光偏转器的电场分布，对不同结构参数，给出了梯度线性度和结构因子。     

双核子削裂、掇取反应的结构因子的研究

本文探讨了影响双粒子削裂、摄取反应强度的结构因子。用集体振荡态的结构波函数(简化的模型)和壳结构波函数对结构因子作了一些分析,发现在集体振荡态的情况下,结构因子随满壳外核子数的变化有显著的规律性。     

非对称螺旋扭曲管管内流动与传热特性数值模拟研究

本文利用数值模拟方法对一种非对称螺旋扭曲管在雷诺数4000~20000的范围内管内流动阻力和传热特性进行了研究.结果表明,与椭圆扭曲管相比,非对称的螺旋扭曲管的努塞尔数得到了显著的提高.通过流场的对比分析可知,非对称螺旋管横截面上的三叶扭曲,使得三叶区域内的流体流动发生偏向,形成强烈的二次旋流使得传热性能得到提升.低雷诺数时,非对称螺旋扭曲管(顺向扭曲)显示出更好的传热性能和更高的阻力因子.随着雷诺数的增加,非对称螺旋扭曲管与对称性螺旋扭曲管的传热与阻力特性差别不大.此外,通过两种不同综合性能因子对比不同管型传热综合性能。在相同泵功率下,非对称螺旋扭曲管在低雷诺数时显示较优的性能,而在相同质量流率下,传统的椭圆扭曲管显示较好的性能。     

自旋-轨道耦合作用下双组分量子气体中的动力学结构因子与求和规则

在自旋-轨道耦合作用下,双组分量子气体中密度涨落和自旋涨落的动力学结构因子满足不同形式的求和规则.特别是动力学结构因子的一阶矩一般不具有空间反演对称性.针对两个特定的模型——Raman耦合作用下的无相互作用费米气体与弱相互作用玻色气体,分别计算了在不同参数条件下密度涨落和自旋涨落的动力学结构因子,并讨论了实验上观测其一阶矩偏离空间反演对称所需达到的能谱分辨率.     

关于中微子的电磁形状因子的测定

近年来高能电子在核上的散射直接肯定了核子具有一定的结构,实验并已较好地测出了质子和中子的电磁形状因子。但是,轻粒子的形状因子还没有测定。在轻粒子中,中微子的形状因子又是一个很有兴趣的问题。由于中微子只参与弱相互作用,所以对它的结构因子的理论分析可能较为简单。我们在工作中曾经指出,通过和电子(或μ介子)的弱相互作用,中微子将具有一定的电磁形状因子。初看起来,通过中微子v_e在电子上的散射,可以测定中微子的电磁形状因子。但是事实上,因为v_e和电子有一级的弱相互     

Nuclear β-decay. I

In order to clarify the validity of the theory of nuclearβ-transition a new formulation is given. The nuclear properties are contained in form factors, arising from a decomposition of the matrix element of the V-A operator for nuclear states. The connection of these form factors with nuclear physics matrix elements is tabulated. The total transition amplitude can be written as an integral over these form factors folded with off-shell amplitudes for elastic and inelastic electron scattering on nuclei.     

Backscattering correction for quantitative Auger analysis: I. Monte Carlo calculations of backscattering factors for standard materials

The electron backscattering effect which is important for the quantitative interpretation of “matrix effects” in AES is investigated by applying the Monte Carlo calculation technique. The present calculation model is based on the use of a precise elastic scattering cross-section obtained by the partial wave expansion method, as well as on the combined use of Gryzinski's excitation function and Bethe's stopping power for inelastic scattering. Systematic calculations of the backscattering factors were performed for over 25 materials including pure elements, compounds, and alloys, which have been widely used as standard materials for practical Auger analysis. The results should enable the accuracy of quantitative analysis by AES to be improved.     

Application of the expansion technique of Harris and Michels to electron-hydrogen inelastic scattering

The algebraic variational method of Harris and Michels has been applied to the calculation of reactance matrix elements in electron-hydrogen scattering, using the 1s-2s-2p close coupling approach. The results are compared to those obtained using other methods.     

0(+)(gs) --> 2(+)(1) excitations in the mirror nuclei 32Ar and 32Si

We measured the strength of the 0(+)(gs)-->2(+)(1) excitations in the radioactive mirror nuclei 32Ar and 32Si using the techniques of intermediate-energy Coulomb excitation for 32Ar and inelastic proton scattering in inverse kinematics for 32Si. The 32Ar measurement, taken together with previously existing Coulomb excitation data for 32Si, yields the isoscalar and isovector multipole matrix elements for the 0(+)(1)-->2(+)(1) transition between T = 2 states in the A = 32 system. The proton scattering measurement for 32Si, when combined with the Coulomb excitation data for this nucleus, yields a ratio of neutron and proton matrix elements, M(n)/M(p), for 32Si.     

Magnetic form factor determination by inelastic scattering of neutrons as compared to elastic scattering measures

The difference between the magnetic form factor for elastic and inelastic scattering of neutrons is derived to interpret recent neutron scattering experiment.     

Microscopic R-matrix theory in a generator coordinate basis: (III). Multi-channel scattering

The microscopic R-matrix theory presented in two previous papers is extended to the multichannel scattering case. An antisymmetrized wave function is built in the two-centre harmonic oscillator model. This wave function is proved to be equivalent to the resonating group one even if the nuclei have non-zero spin. The method only requires the calculation of numerical values of matrix elements between Slater determinants. The microscopic R-matrix theory may be applied to study both reactions and inelastic scattering.     

Coordinate space structure in the parton model

We study the relation between the parton model and light cone analyses for highly inelastic leptonic processes. Results are displayed which follow from scaling laws in general, independently of specific parton model predictions. We conclude that the assumptions of the light cone analysis of inelastic electron scattering are supported by the parton model. However, the parton model matrix element for massive muon pair production is not light-cone dominated, nor does it have the same light cone singularity as inelastic electron scattering.     

Microscopic transport theory of heavy-ion collisions

Drift and diffusion coefficients for the variables of mass fragmentation and excitation energy are studied for deeply inelastic collisions. The transport coefficients are obtained in closed form as functions of the parameters of the interaction matrix elements between nucleonic states and as functions of the binding energy of the intermediate rotating quasimolecular configuration. Drift and diffusion coefficients for excitation and mass transfer are related (dissipation fluctuation theorem). In good approximation these relations take the simple form of Einstein's relation between the mobility and the diffusion coefficient of a particle in a medium. For the total mass numbers 100, 250 and 500 the results are discussed in detail. The transport coefficients are compared with experimental results. Within the uncertainties of determination from experimental data, the drift and diffusion coefficients are well described by two previously adjusted parameters of the mean interaction matrix elements. Consequences for the production of superheavy elements in deeply inelastic collisions of U on U or Cf are discussed.