Lattice instability in ZnSe:Ni crystal

Ultrasonic experiments, done on ZnSe:Ni crystal with the dopant concentration 5.5×10¹⁹ cm⁻³, revealed precursor phenomenon in the form of lattice softening at temperatures significantly exceeding the temperature of structural transition (T_c=14.5 K). It proved to be that the order parameter of the transition was associated with the shear deformation ε₄. Investigation of thermal conductivity (κ) in the same temperature region pointed out that the Jahn-Teller (JT) effect could be responsible for the anomalous behavior of κ(T) and lattice instability.     

Internal quantum efficiency for solar cells

The total internal quantum efficiency (IQE) of a flat-band p–n homojunction silicon solar cell and contributions of the three regions to it are numerically evaluated. It is found that both the spatial widths of the cell and the surface recombination velocities have significant impacts on the IQEs. By a linear transformation and a proper approximation, the differential equation of the minority carrier density in a textured cell becomes the same form as for the flat cell. What makes differences is that texturization slightly enhances the IQEs for photons with longer wavelengths while notably increasing external quantum efficiency. Hence it plays a good role for getting a better performance of a solar cell. It is considered that the results in the present are of universal technical importance both in designing solar cells and their surface structures.     

基于量子遗传算法的粗糙集属性约简的研究

将粗糙集理论应用于股市的分析与研究,除了采用已有的约简方法进行试验之外,还引入了量子计算与遗传算法相结合的方法来进行粗糙集的属性约简.与其他约简算法不同的是,该算法采用量子旋转门策略来达到全局最优搜索和较高的收敛速度.最后,通过具有代表性的股票数据证明了该方法的有效性和高效性.     

二能级原子与相干态腔场之间的量子信息转移

利用二能级原子与腔场的大失谐相互作用Jaynes-Cummings(J-C)模型,提出了一种量子信息转移的方案.分别实现了单原子与单个腔场,纠缠的多个原子与单个腔场,及多个原子与多个腔场之间的量子信息的双向传递.     

用光梯度场控制原子制做纳米点阵研究

提出制做纳米点阵的一种新方法。用波长为 4 2 5 .5 nm的光梯度场操纵铬原子可制做出阵列密度达 2 .2 1× 10 7per/ mm2、理论半高宽度 (FWH M)可达 10 nm的纳米点阵。介绍用光梯度场操纵原子制做纳米点阵的原理 ,对原子束的准直进行分析 ,给出原子束在激光梯度场中聚焦的经典模型和量子模型并进行数值模拟。用光操纵原子制做纳米点阵使器件的阵列密度和尖端曲率得到大幅度提高 ,该器件作为发射极可以降低工作电压和提高发射电流。     

半导体量子器件

概述了半导体量子微结构中的量子效应，并介绍了谐振隧道器件，评述了新的量子微结构，如单电子隧道器件，电子波衍射晶体管和量子线量子箱激光器的开发，还讨论了量子微结构的尺寸要求和研究课题。     

High thermoelectric figures of merit in PbTe quantum wells

High-quality Pb_1−xEu_xTe/PbTe multiple quantum wells (MQWs) have been grown by molecular beam epitaxy. The measured 300K thermoelectric properties have been compared with that of the best bulk PbTe. This experimental investigation is the first detailed study of MQW structures designed to improve ZT of thermoelectric materials and has resulted in a breakthrough in the decades-long ZT ≅ 1 barrier for a room-temperature thermoelectric material. A value of Z_2DT >1.2 has been achieved for these PbTe quantum wells.     

稠油破乳作用机理的量子化学和分子力学研究

 采用半经验量子化学和分子力学方法，全优化计算了稠油中胶质模型化合物(SG)、双层结构胶质模型化合物 (DG)和含磺酸基团的破乳剂分子插入双层胶质形成的超分子模型(DGHB)的结构，探讨了破乳作用机理。结果表明， DG模型化合物分子间存在氢键，其作用能为 22.8416kJ/mol；含磺酸基团的破乳剂插入胶质双层结构后，破坏了胶质分子间的氢键。计算结果预示，含有强亲水基团的磺酸盐和带支链烷基的破乳剂可破坏稠油中胶质分子间的氢键，起到稠油破乳之功效。     

Macroscopic isotropy of two- and three-dimensional elastic lattice models

Particle methods such as the meso-particle method or the method of movable cellular automata provide new possibilities for the simulation of wear, mass-transfer, plastic deformation and melting processes. One crucial point, however, is to ensure that in the continuum limit macroscopic isotropy is guaranteed. We show how this can be done in two- and three-dimensional lattices.     

Spin–Lattice Relaxation of Mn Ions in Nanostructures with Semiconductor Quantum Dots

We use the combination of nonequilibrium phonon and exciton luminescence techniques to study the spin dynamics in diluted magnetic semiconductor structures with (Cd,Mn)Te and (Cd,Mn)Se quantum dots (QDs). We show that the spin–lattice relaxation (SLR) of Mn ions in these structures differs strongly from the SLR in quantum wells. We explain the results by a model where SLR process in structures with QDs is modified by the spin diffusion on Mn ions from the QD to a wetting layer.