Effects of growth temperature on highly mismatched InAs grown on GaAs substrates by MBE

InAs layers were grown on GaAs by molecular beam epitaxy (MBE) at substrate temperature 450 and 480 degrees C, and the surface morphology was studied with scanning electron microscopy (SEM). We have observed a high density of hexagonal deep pits for samples grown at 450 degrees C, however, the samples grown at 480 degrees C have smooth surface. The difference of morphology can be explained by different migration of cations which is temperature dependent. Cross-sectional transmission electron microscopy (XTEM) studies showed that the growth temperature also affect the distributions of threading dislocations in InAs layers because the motion of dislocations is kinetically limited at lower temperature. (C) 1998 Elsevier Science B.V. All rights reserved.

Rapid thermal annealing processing of GaN epilayer on sapphire(0 0 0 1)

The effect of rapid thermal annealing (RTA) in a Nz ambient up to 900 degrees C has been investigated for GaN films grown on sapphire(0 0 0 1) substrates. Raman spectra, X-ray diffractometry and Hall-effect studies were performed for this purpose. The Raman spectra show the presence of the E-2 (high) mode and a shift in the wave number of this mode with respect to the annealing processing. This result suggests the presence and relaxation of residual stress due to thermal expansion misfit in the films which are confirmed by X-ray measurements and the structure quality of GaN epilayer was improved. Furthermore, the electron mobility increased at room temperature with respect to decrease of background electron concentration after RTA. (C) 1998 Elsevier Science B.V. All rights reserved.

视频监控系统网管子系统的设计和实现

随着社会信息化程度的不断提高，社会各行各业需要实施远程视频监控的范围大大增加，由传统的安防监控向管理监控和生产经营监控发展，对远程视频监控系统的要求也日益提高，往往需要与网络系统相结合，实现对大量视频数据实时、无地域阻碍地传输，为各级管理人员和决策者提供方便、快捷、有效的服务。 本文以下一代互联网中的视频监控应用需求为背景，介绍了视频监控和网络管理协议的相关内容，提出了基于SNMP协议的网络管理方案，设计并实现支持IPv4/IPv6双协议栈的网管系统。网管系统包括网管代理和网管服务器，主要功能是采集和记录网络视频监控系统中各种设备的工作状态数据，维护一个设备管理数据库，为管理员提供管理和监控视频监控网络系统运行情况的平台，以便及时发现系统出现的故障和异常情况，保证系统能稳定运行。 本文工作主要贡献以下： 1) 参与设计视频监控系统的整体框架和子系统间接口； 2) 提出以SNMP协议为基础的视频监控系统中的网络管理实现方案； 3) 设计了视频监控系统中的网络管理子系统框架； 4) 提出了用于管理大规模视频监控系统的特定管理信息集，设计并实现了视频监控系统网管子系统中的网管代理和网管服务器，还在CNGI网络上提供了该系统的示范应用。

identity based threshold proxy signature

IEEE Computer Society

自动化回归测试的技术和实现

提出了两种提高回归测试自动化程度的技术。其中一种技术采用数据驱动的方式,使得测试脚本成为可以驱动所有类似测试用例组的通用脚本,同时,实现了测试执行和测试逻辑的分离,使得测试用例的修改和维护更加容易。介绍的另一种技术使用附加的动态链接库来恢复被测软件的图形界面状态,使得软件图形界面的自动测试不易受到被测软件状态改变的影响,提高了整个自动测试系统的健壮性。

移动自组网中基于节能的AODV路由协议改进

在AODV路由算法的基础上,综合考虑节点剩余能量和跳数,提出了一种新的节能路由策略.该策略同时对数据包和路由控制包进行功率控制,改进了Hello机制.仿真结果显示该策略显著地提高了节能效果,延长了网络的生存时间.