认证字典的一种新的分类方法

认证字典是一类重要的数据结构,它在众多研究领域都具有重要的理论和应用价值,诸如科学数据挖掘、地理数据服务器、Internet上的第三方数据发布以及PKI中的证书撤销等。该文介绍了认证字典的基本概念与原理;首次在认证字典模型中引入了时间约束,并据此给出了认证字典的一种新的分类方法,探讨了认证字典的实现技术。最后,简要讨论了认证字典在PKI/WPKI中的应用。     

Magneto-absorption of donor impurities in quantum-well wires

We show calculations for far-infrared absorption of shallow-donor impurities in quantum well wires in the presence of an external magnetic field. The wave functions and the eigenvalues are obtained in the effective-mass approximation by using an extended variational approach in which the ground and excited magneto-impurity states are simultaneously obtained. We investigate the allowed intra-donor transitions for radiation circularly polarized in the plane perpendicular to the magnetic field. We present results for the absorption coefficient as a function of the photon energy for several field strengths and arbitrary impurity positions.     

Temperature dependent optical properties of stacked InGaAs/GaAs quantum rings

In this paper we describe the results of temperature dependent photoluminescence intensity and decay time measurements of In(Ga)As/GaAs quantum rings where the depth of barrier is varied from sample to sample. The activation energy found for the reduction of the exciton decay time as a function of the temperature is approximately half the value of the thermionic escape energy of excitons. The temperature dependant behaviour is ascribed to the carriers lost via the excited state to the WL.

The time resolved PL study indicates that thermal escape mechanisms is not so affected by reducing the spacer thickness, but it's influenced essentially by the excited state recombination.     

PLC在20MN快速锻压机上的应用

以Modicon Quantum（昆腾）系列PIE在20MN快速锻压机上的具体应用，着重描述了系统配置及控制功能。     

Computational analysis of the refractive index of multiple quantum wells for QWSC applications

In this paper, the authors extend on previous work regarding a new approach to calculating the refractive index of the quantum wells of a quantum well solar cell device. The new approach is computational and considers the presence of an electric field perpendicular to the quantum well layers. The model is based on the modified single effective oscillator (MSEO) model. The MSEO model is dependent upon three specific parametric equations. Using the relationships between these equations and how electric field effects these three parameters. The effects of the electric field on the refractive index of the quantum well layer can be determined. Computational analysis under AM 1.5 conditions for a hypothetical quantum well structure is performed with any discrepancies in the approach discussed.     

Lattice quantum hadrodynamics on a CRAY Y-MP

Quantum corrections to the mean-field equation of state for nuclear matter are estimated in a lattice simulation of quantum hadrodynamics on a CRAY Y-MP. In contrast with lattice quantum chromodynamics, where coordinate space methods are the standard, the calculations are carried out in momentum space and on nonhypercubic (irregular) lattices. The quantum corrections to the known, mean-field equation of state were found to be considerable. The time frame of the project and the large computational needs of the program required the use of powerful supercomputers, like the CRAY Y-MP, which are capable of performing at a very high computing speed by using both vector and parallel hardware, the latter being exploited by means of autotasking. The paper describes the applied analytical and the numerical methods as well as the changes needed for the program to be executed in parallel. After some code modifications a very efficient version could be obtained on a CRAY Y-MP8/832, leading to an overall performance of 2.13 gigaflops.     

A new approach to modelling quantum dot concentrators

Luminescent collectors have advantages over geometric concentrators in that tracking is unnecessary and both direct and diffuse radiation can be collected. However, development has been limited by the performance of luminescent dyes. We have recently proposed a novel concentrator in which the dyes are replaced by quantum dots (QDs). Advantages over dyes include that the absorption threshold can be tuned by choice of dot diameter, and that the red shift between absorption and luminescence is related to the spread of dot sizes. In this paper we discuss how we have developed a self-consistent thermodynamic model for planar concentrators which allows for re-absorption by the QDs.     

二元Bent序列的前馈生成＊

通过对[1]中二元Bent序列的等价定义,本文给出了使用前馈网络生成二元Bent序列的快速方法,使二元Bent序列的产生比[2]中的方法简单,迅速。     

能带工程对电子和光子器件发展的影响

简要概述能带工程的概念,能带工程的外延手段和常用材料的特性,并介绍了以能带工程为基础的几种新器件.     

电磁导弹的可实现性问题

由于电磁场的量子化效应,电磁系统发射有限能量的电磁场,其频谱必有一高频率上限。本文指出,现有的电磁导弹理论是基于经典理论。电磁导弹在物理上不可能实现。任何涉及实现和利用电磁导弹现象的理论分析和实验企图必定与现有的量子理论相冲突。