电解沉积的分形维数与ZnSO_4溶液浓度的关系

用电沉积方法得到了不同浓度硫酸锌电解液的分形凝聚图像;进行图像处理,得到了其分形维数与浓度的关系曲线;用粒子扩散限制凝聚模型解释了此关系     

Role of gallium wetting layer in high-quality ZnO growth on sapphire (0001) substrates

ZnO is a wide direct bandgap (Eg=3.37 eV at room temperature) II-VI compound semiconductor of wurtzite structure (a = 3.249 ? c = 5.207 ?. Compared to GaN and ZnS, ZnO has a larger exciton binding energy, ~60 meV (cf. ~25 meV for GaN and ~40 meV for ZnS), which is advantageous to realizing low-threshold excitonic lasers. Since optically pumped UV lasing of ZnO at room temperature was reported in 1997[1], much attention has been paid to the crystal quality improvement and p-type conduc…     

一种研究自旋翻转散射效应的新方法

金属中自旋翻转散射长度远长于电子平均自由程，近来关于自旋翻转散射效应的研究主要集中于扩散区域．文章作者提出了一种使用双势垒磁性隧道结来研究纳米尺度结构中弹道区域的自旋翻转散射效应的新方法．这种方法可以从磁电输运性质的测量，得出中间隔离层中的自旋翻转散射效应的温度和偏压关系，进一步可以得出诸如电子平均自由程和自旋翻转散射长度等自旋散射信息，以及中间层的态密度和量子阱信息．     

Effect of magnon–phonon interaction on transverse acoustic phonon excitation at finite temperature

A magnon–phonon interaction model is developed on the basis of two-dimensional square Heisenberg ferromagnetic system. By using Matsubara Green function theory transverse acoustic phonon excitation is studied and transverse acoustic phonon excitation dispersion curves is calculated on the main symmetric point and line in the first Brillouin zone. On line Σ it is found that there is hardening for transverse acoustic phonon on small wave vector zone (nearby point Γ), there is softening for transverse acoustic phonon on the softening zone and there is hardening for transverse acoustic phonon near point M. On line Δ it is found there is no softening and hardening for transverse acoustic phonon. On line Z it is found that there is softening for transverse acoustic phonon on small wave vector zone (nearby point X) and there is hardening for transverse acoustic phonon nearby point M. The influences of various parameters on transverse acoustic phonon excitation are also explored and it is found that the coupling of the magnon–phonon and the spin wave stiffness constant play an important role for the softening of transverse acoustic phonon.     

Electronic transport properties and Microstructures of TiO2:Co magnetic semiconductors

TiO₂:Co thin films of high Co concentration were investigated by the high resolution transmission electron microscopy, physical property measurement system and energy dispersive X-ray. The as-deposited films are amorphous magnetic semiconductors and we did not find any Co metal particles in them. The electronic transport process in the low-temperature range below 80 K could be described by the spin-dependent variable-range-hopping process. However, after the samples were annealed at 300 °C, large amounts of Co metal particles were observed to connect each other and the films show a metallic behavior. The origin of ferromagnetism of the thin films is also discussed.     

Periodic entanglement of magnons in an antiferromagnet

The dynamics of entanglement for two-mode magnons in an antiferromagnet is investigated according to the entanglement criterion proposed by Duan et al. [L.M. Duan, G. Giedke, J.I. Cirac, P. Zoller, Phys. Rev. Lett. 84 (2000) 2722]. It is shown that entanglement between the two modes of magnons can be generated and occurs periodically with time.     

Magnetic properties,electronic structure,and optical properties of the filled skutterudite BaFe4Sb12

The magnetic properties, electronic structure, and optical properties of the filled skutterudite BaFe₄Sb₁₂ are calculated by the first-principles full-potential linearized augmented plane wave (FPLAPW) plus local orbital method. It is found that the local spin density approximation (LSDA) method appears more accurate than the generalized gradient approximation (GGA) method in calculating the electronic structures and optical properties of this compound. Furthermore, our calculated lattice constant and spin magnetic moments with the LSDA method are in overall better agreement with experiment. In contrast with recent experiment, our calculations are in good agreement with experimental reflectivity spectra and optical conductivity spectrum.     

具有不可缩小Beltrami系数的拟共形映射

本文讨论了不可缩小Beltrami系数与无限小不可缩小Beltrami系数的局部 性与整体性的关系;并通过烟囱形区域上仿射拉伸的实例,指出构造一类极值的具有 非常数模的不可缩小Beltrami系数与无限小不可缩小Beltrami系数的方法.     

Ordered Solid‐State Microstructures of Conjugated Polymers Arising from Solution‐State Aggregation

Controlling the solution‐state aggregation of conjugated polymers for producing specific microstructures remains challenging. Herein, a practical approach is developed to finely tune the solid‐state microstructures through temperature‐controlled solution‐state aggregation and polymer crystallization. High temperature generates significant conformation fluctuation of conjugated backbones in solution, which facilitates the polymer crystallization from solvated aggregates to orderly packed structures. The polymer films deposited at high temperatures exhibit less structural disorders and higher electron mobilities (up to two orders of magnitude) in field‐effect transistors, compared to those deposited at low temperatures. This work provides an effective strategy to tune the solution‐state aggregation to reveal the relationship between solution‐state aggregation and solid‐state microstructures of conjugated polymers.