Monitoring of CdTe atomic layer epitaxy using in-situ spectroscopic ellipsometry

Atomic layer epitaxy or ALE has proven to be useful for the growth of epitaxial layers of high uniformity, good quality, and well-controlled thickness. In this study, we have carried out in-situ monitoring during the atmospheric pressure ALE of CdTe on GaAs (100) substrates using spectroscopic ellipsometry (SE). The susceptor temperature, reactant partial pressures, as well as the flow and flush duration for each precursor are crucial process variables for ALE growth. Growth was carried out for 20–25 cycles under different sets of these process conditions during the experiment and in-situ SE was used to verify the presence of layer-by-layer growth, which enabled the quick determination of the process window. We observed ALE growth of CdTe at 300°C, supporting the explanation that the growth of CdTe occurs via a surface catalyzed decomposition of the Te precursor di-isopropyltelluride (DIPTe). Investigation of ALE mode growth behavior for different susceptor temperatures and DIPTe flush times indicated that the growth was limited by competition between desorption and reaction of the adsorbed DIPTe species on the Cd terminated surface.     

西门子自动化实验室的建立及应用

介绍以西门子S7-300/200PLC、WINCC6.0、MM440变频器、6SE70系列变频器等产品为基础建立的莱钢新区炼钢厂西门子自动化实验室。     

Comparing interpolation techniques for monthly rainfall mapping using multiple evaluation criteria and auxiliary data sources: A case study of Sri Lanka

Interpolating climatic variables such as rainfall is challenging due to the highly variable nature of meteorological processes, the effects of terrain and geography, and the difficulty in establishing a representative network of stations. While interpolation models are being adapted to include these effects, often the rainfall data contain significant gaps in coverage. In this paper, we evaluated rainfall data from an agro-ecological monitoring network for producing maps of total monthly rainfall in Sri Lanka. We compared four spatial interpolation techniques: inverse distance weighting, thin-plate splines, ordinary kriging, and Bayesian kriging. Error metrics were used to validate interpolations against independent data. Satellite data were used to assess the spatial pattern of rainfall. Results indicated that Bayesian kriging and splines performed best in low and high rainfall, respectively. Rainfall maps generated from the agro-ecological network were found to have accuracies consistent with previous studies in Sri Lanka.     

Protel 99SE在电液仿形系统电路设计中的应用

介绍了Protel 99SE应用软件的功能特点以及设计电路的一般方法步骤,结合实际在电液仿形系统电路设计中的应用,指出了设计中遇到的一些问题,并给出了具体的解决方法和注意事项,对学习和应用Protel?9SE会有一定的帮助.     

基于Rsview SE的铜电解监控系统的设计与开发

本文先对监控系统系组态软件RSview SE及监控画面的设计流程做了介绍,接着以某铜业公司铜电解自动化系统为例,从监控画面的几个组成部分来设计和开发监控系统画面。     

Protel 99SE电路仿真

电路仿真可提高电路设计效率和降低成本。文章从实际应用的角度出发 ,全面介绍了Protel 99SE电路仿真功能 ,旨在让更多的电子设计工程师了解和掌握此电路分析设计工具 ,并令其在电子设计过程中发挥作用。     

Estimation of catchment-scale water-balance with a soil-vegetation-atmosphere transfer model

Catchments with a small elevation range and relatively long dry periods in high radiation conditions may be described as an array of vertical one-dimensional pathways for water and energy. Such a representation enhances the ability of SVAT modeling to simulate mass exchanges across the catchment. This note reports on a comparison of a Soil-Vegetation-Atmosphere Transfer (SVAT) model (Braud et al., 1995), a deterministic hydrological model (Dawes and Hatton, 1993) and a stochastic hydrological model (Sivapalan and Woods, 1995; Kalma et al., 1995). The original version of the SVAT model only considers vertical transport and this one-dimensional representation must be aggregated to describe the entire catchment. Therefore, two new versions have been developed: a deterministic SVAT model which sub-divides the catchment into 40 sub-regions linked by surface flow, and a stochastic model which provides a distribution of the output fluxes as related to the spatial distribution of initial water content and/or soil properties. All simulations have been made for a 60-day period.     

SE Linux安全策略灵活性研究

安全操作系统要能够灵活充分地支持大量广泛的安全策略。这些灵活性需要支持控制访问权限的转移，执行细粒度的访问控制和撤消之前许可的访问权限。当前的一些系统在这些方面有所欠缺。本文介绍了一种操作系统安全构架可以解决当前的这些问题。构架提供了针对每个安全决策必须与安全策略做出协商的转移控制机制，使用保证安全决策一致性的安全决策缓存，并在服务组件中提供了细粒度的访问控制和撤消机制。     

基于XYZ/SE的软件部分正确性验证

针对软件形式化描述和正确性验证研究中存在的问题,提出了基于XYZ/SE的统一框架研究该问题。在该框架下,基于逐步求精思路对软件进行抽象;对软件整体进行形式化描述和部分正确性验证;对抽象得到的软件各部分进行形式化描述和部分正确性验证;进行调整和验证,即：如果推导结果与预期不一致,则需要重写相关程序或者回溯检查推导过程是否存在错误,直至程序部分正确性得到验证为止。以国库信息处理系统为对象,分析了基于XYZ/SE的统一框架性能。分析表明,基于该框架能够对软件的不同抽象层次进行规范描述,实现从抽象（静态语义）到具体（动态语义）的平滑过渡。同时,基于XYZ/SE的统一框架也可以表示Hoare逻辑推演规则。