Modeling and simulation of an oxy-fuel combustion boiler system with flue gas recirculation

In this paper, a mathematical model of an oxy-fuel combustion boiler system with flue gas recirculation is investigated. The reduction of CO₂ emission from coal-fired power plants is an important research issue in alleviating the global warming. The entire dynamics are decomposed in two main parts; fire-side dynamics and water-side dynamics. The fire-side dynamics consist of the mass and energy balance equations in the furnace (combustion process) and the flue gas dynamics represented by the mass balance equations of five gases (O₂, CO₂, SO₂, H₂O and NO₂). The water-side dynamics include a drum pressure equation and a steam temperature equation. To validate the developed models, the real experimental data in Karakas, Koumanakos, et al. (2007) are used. To investigate the local behavior near an operating point, a linearization method at its steady-state condition is pursued. The time responses of the entire dynamics using step inputs (the oxygen mass flow rate, the coal mass flow rate, the primary air mass flow rate, etc.) are also discussed.     

RC／SRC结构梁柱边节点抗剪强度的试验研究

通过十个RC/SRC梁柱边节点在低周反复荷载作用下的试验,对RC/SRC梁柱边节点的破坏特征、剪切强度等问题进行了探讨,最后,给出了RC/SRC边节点抗剪强度计算公式。     

简易语音频宽演示仪

采用电子技术和单片微型计算机技术相结合的方法设计出简易语音频宽演示仪，主要组成部分有４８个相互独立的ＲＣ有源带通滤波器，利用ＤＳ－９８Ｃ型单片机教学开发机实现语音频宽的显示。     

钢筋混凝土柱爆破实验的灰关联分析

拆除爆炸中,如何设计好各种构件,如柱、梁的爆破,是建筑物能够倒塌解体的关键技术之一.在钢筋混凝土柱的爆破实验因素分析中引入新的分析方法--灰关联分析法.分析结果包含了设计主要参数与结果参数之间的各种变化关系,与关系曲线法分析结果作了对照,表明这种方法具有一定推广价值.     

Parallel application performance on shared high performance reconfigurable computing resources

The use of a network of shared, heterogeneous workstations each harboring a reconfigurable computing (RC) system offers high performance users an inexpensive platform for a wide range of computationally demanding problems. However, effectively using the full potential of these systems can be challenging without the knowledge of the system's performance characteristics. While some performance models exist for shared, heterogeneous workstations, none thus far account for the addition of RC systems. Our analytic performance model includes the effects of the reconfigurable device, application load imbalance, background user load, basic message passing communication, and processor heterogeneity. The methodology proves to be accurate in characterizing these effects for applications running on shared, homogeneous, and heterogeneous HPRC resources. The model error in all cases was found to be less than 5% for application runtimes greater than 30 s, and less than 15% for runtimes less than 30 s.     

Win32环境下的OpenGL程序设计

OpenGL是目前公认的三维图形开发标准,在Win32环境下开发高质量高性能的三维图形应用程序,OpenGL是比较理想的选择。简要介绍Win32环境下,使用OpenGL进行图形操作的具体步骤,详细介绍Win32环境下进行Open-GL编程涉及的相关技术细节,如关联设备描述表和绘制描述表、图形显示与重绘、实时动画与交互操作等,并编写一个简单的动画例程,较全面地演示了Win32环境下的OpenGL编程方法。     

基于计算可靠度的现有RC结构构件的安全等级划分研究

在考虑现有RC结构构件的后续使用年限和抗力衰减的基础上,利用计算的民用RC结构构件在不同情况下的可靠指标,研究了构件计算的可靠指标与其安全等级之间的关系;将现有RC结构构件的可靠指标的定量计算与鉴定时的分级定性评定结合,经过计算和与设计规范的要求比较,给出了安全等级划分评定时的计算可靠指标标准.提出的民用建筑结构RC构件鉴定时安全等级划分评定的量化方法,可应用于现有结构构件的鉴定中;得出的鉴定等级安全性与设计规范的安全性是一致的,实现了民用结构RC构件鉴定的定量计算.     

复合砂浆钢筋网加固RC简支梁抗剪性能的试验研究

复合砂浆钢筋网薄层加固是一种有效的新型加固方法,能够显著地提高钢筋混凝土梁的抗剪承载力以及抗裂性能.在6根复合砂浆钢筋网加固RC简支梁和1根对比梁的试验基础上,研究了加固梁各种参数对梁极限抗剪承载力的影响,并分析对比了各组加固梁的破坏形态、斜裂缝、荷载-跨中挠度曲线的变化规律.给出了复合砂浆钢筋网加固RC梁的极限抗剪承载力计算公式,计算结果与试验结果吻合较好.     

RC6中不同固定循环移位对差分分析的影响

论文首先讨论了不同的固定循环移位对RC6-I(用恒等函数代替平方函数的变体)的影响,从理论上证明了当固定循环移位的取值为lgw时,RC6-I抗差分分析的效果最好。     

From MC/DC to RC/DC: formalization and analysis of control-flow testing criteria

This paper describes an approach to the formalization of existing criteria used in computer systems software testing and proposes a new Reinforced Condition/Decision Coverage (RC/DC) criterion. This new criterion has been developed from the well-known Modified Condition/Decision Coverage (MC/DC) criterion and is more suitable for the testing of safety-critical software where MC/DC may not provide adequate assurance. As a formal language for describing the criteria, the Z notation has been selected. Formal definitions in the Z notation for RC/DC, as well as MC/DC and other criteria, are presented. Specific examples of using these criteria for specification-based testing are considered and some features are formally proved. This characterization is helpful in the understanding of different types of testing and also the correct application of a desired testing regime. Received July 2004 Revised November 2005 Accepted November 2005 by J. Derrick, M. Harman and R.M. Herons