Anomalous Hall effect of heavy holes in III-V semiconductor quantum wells

The anomalous Hall effect of heavy holes in semiconductor quantum wells is studied in the intrinsic transport regime, where the Berry curvature governs the Hall current properties. Based on the first--order perturbation of wave function the expression of the Hall conductivity the same as that from the semiclassical equation of motion of the Bloch particles is derived. The dependence of Hall conductivity on the system parameters is shown. The amplitude of Hall conductivity is found to be balanced by a competition between the Zeeman splitting and the spin--orbit splitting.     

Persistent spin current in a quantum wire with weak Dresselhaus spin——orbit coupling

The spin current in a parabolically confined semiconductor heterojunction quantum wire with Dresselhaus spin--orbit coupling is theoretically studied by using the perturbation method. The formulae of the elements for linear and angular spin current densities are derived by using the recent definition for spin current based on spin continuity equation. It is found that the spin current in this Dresselhaus spin--orbit coupling quantum wire is antisymmetrical, which is different from that in Rashba model due to the difference in symmetry between these two models. Some numerical examples for the result are also demonstrated and discussed.     

极性晶体中强耦合表面磁极化子特性

研究极性晶体中表面磁极化子的特性。采用Huybrechts线性组合算符和幺正变换方法,导出了晶体中强耦合表面磁极化子处于基态的振动频率和有效哈密顿量,讨论了坐标z的两种极限情况,对RbCl晶体进行了数值计算。结果表明:振动频率和平行有效哈密顿量随磁场的增加而增大。     

不同电磁脉冲对细导线的耦合

 采用时域有限差分法,结合细线处理方法,分别对超宽带电磁脉冲、快前沿电磁脉冲和核电磁脉冲在自由空间细导线上耦合的电流进行了数值计算,得出了不同前沿和脉宽的电磁脉冲在细导线上的感应电流。     

纳米晶复合永磁材料的交换耦合相互作用和磁性能

本介绍了纳米磁性材料晶粒交换耦合相互作用的有关理论。采用不同模型讨论了晶粒交换耦合相互作用对纳米单相软磁材料、永磁材料及双相复合永磁材料磁性能的影响。简述了用δM（H）曲线和不可逆磁导率的变化研究晶粒交换耦合相互作用及反磁化过程的方法。讨论了合金分配比、添加元素、制备及热处理工艺对磁体硬磁性能的影响。从理论和实验两方面分析、研究了纳米复合永磁材料的反磁化过程和矫顽力机制。     

Determination of Backbone Angle ψ in Proteins Using a TROSY-Based α/β-HN(CO)CA-J Experiment

Transverse relaxation-optimized NMR experiment (TROSY) for the measurement of three-bond scalar coupling constant between ¹H^α_i−1 and ¹⁵N_i defining the dihedral angle ψ is described. The triple-spin-state-selective experiment allows measurement of ³J_H^αN from ¹³C^α, ¹⁵N, and ¹H^N correlation spectra H₂O with minimum resonance overlap. Transverse relaxation of ¹³C^α spin is minimized by using spin-state-selective filtering and by acquiring a signal longer in ¹⁵N-dimension in a manner of semi-constant-time TROSY evolution. The ³J_H^αN values obtained with the proposed α/β-HN(CO)CA-J TROSY scheme are in good agreement with the values measured earlier from ubiquitin in D₂O using the HCACO[N] experiment.     

Reinvestigation of the second negative (A 2 Π u−X 2 Π g) band system of O 2 +

TheA ² Π _ustate of O₂ ⁺ was earlier established as an inverted state contrary to previous assumptions. The rotational analysis of a few more bands of theA-X system of O₂ ⁺ has now been completed. These studies show that the spin-orbit coupling constantA in theA ² Π _ustate gradually varies with the vibrational quantum numberν and is found to be positive forν⩾6. It has also been observed that the spia-rotation interaction is not negligible in theA ² Π _ustate. The spin splitting constantγ is reported for various vibrational levels of this electronic state.     

^143Pm高自旋态研究

通过熔合蒸发反应^129Te(^19F,4nγ）布居了^143Pm的高自旋态,利用在束γ谱学方法,对^143Pm的高自旋态核结构进行了研究,测量了γ射线单谱和γ－γ符合谱,并进行了γ射线各向异性以及DCO比率分析,建立了激发高能达10535．4keV的能级纲图,其中包括新发现的32条γ射线和17个新能级,用弱耦合模型对^143Pm的晕态能级结构进行了解释。     

Fluctuations in nonequilibrium systems and broken supersymmetry

The fluctuation-dissipation theorem is not expected to hold for systems that either violate detailed balance or have time-dependent or nonpotential forces. Therefore the relation between response and correlation functions should have contributions due to the nonequilibrium nature. An explicit formula for such a contribution is calculated, which in the present derivation appears as a historydependent term. These relations are the Ward-Takahashi identities of a supersymmetric formulation of the Langevin models, and the new term results from a broken supersymmetry.     

A simplified cavity analysis for estimating energy coupling during laser ablation and drilling of solids — experiment

The theory for a general departure function, f, for laser-irradiated cavities was previously developed to estimate laser energy coupling to an opaque solid target as a function of heat transfer and the cavity shape and size. In this article, a specific form of f is calculated for ultraviolet (UV) laser ablation of copper (Cu) and aluminum (Al) targets. Methods are also given for calculating the geometric factor, a, and experimentally determining the heat transfer parameter, ν, which is shown for this form of f to be the intensity-dependent effective reflectivity of the material. Experimental results for different gauges of laser energy coupling with a solid target are given and compared to calculations of net absorbed energy based on f and the incident laser energy. Using the simplified cavity analysis, the results demonstrate that the experimental values for f fall within the limits predicted by the theory, and that energy coupling can be predicted to within a mean of 2% of experimental gauges. Neglecting the factors in f from calculations of energy coupling can lead to large errors for laser-irradiated cavities, establishing that both cavity shape and heat transfer should be simultaneously considered. In addition, a first-order sensitivity analysis based on f shows that the initial rate of change in material removal strongly increases with reflectivity, which can lead to runaway cavity formation for highly reflective materials.