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Mehrdad Boroushaki Mohammad B. Ghofrani Caro Lucas Mohammad J. Yazdanpanah Nasser Sadati 《Nuclear Engineering and Design》2004,227(3):285-300
Improved load following capability is one of the main technical performances of advanced PWR (APWR). Controlling the nuclear reactor core during load following operation encounters some difficulties. These difficulties mainly arise from nuclear reactor core limitations in local power peaking, while the core is subject to large and sharp variation of local power density during transients. Axial offset (AO) is the parameter usually used to represent of core power peaking, in form of a practical parameter. This paper, proposes a new intelligent approach to AO control of PWR nuclear reactors core during load following operation. This method uses a neural network model of the core to predict the dynamic behavior of the core and a fuzzy critic based on the operator knowledge and experience for the purpose of decision-making during load following operations. Simulation results show that this method can use optimum control rod groups maneuver with variable overlapping and may improve the reactor load following capability. 相似文献
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PLC和触摸屏组合控制系统的应用 总被引:7,自引:0,他引:7
为了使PLC的应用更加灵活并实现可视化,对PLC和触摸屏组合控制系统进行了研究。分别采用S7-200 CPU224XP和迪文触摸屏作为系统的控制器和人机界面,采集现场的温度、压力信号,控制现场的执行机构。详细阐述了触摸屏界面的制作方法、PLC程序的设计方法及设计过程中遇到的问题。考虑到西门子PLC和迪文触摸屏之间不能进行直接通信,在分析了迪文触摸屏的数据帧结构及数据传送方式的基础上,设计了无源RS-485/RS-232转换电路。系统已投入运行,其运行效果良好。 相似文献
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基于PLC的原煤输配控制系统设计与应用 总被引:2,自引:1,他引:1
阐述了选煤厂原煤输配系统采用PLC控制的主要特点,对输煤部分和配煤部分的电气控制系统进行硬件组态、软件设计,用压力继电器检测煤位高低以控制煤流大小,实现高精度配煤,系统中加入完善的连锁保护、报警和显示功能,突出了PLC在工业控制系统中的应用。 相似文献
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文章结合新钢公司新建2500m3高炉炉渣处理工艺,设计开发了渣处理PLC自动控制系统,介绍了该系统的组成,功能及其应用。 相似文献
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介绍一种基于PC机为上位机,以PLC为下位机组成的半自动配料系统在橡胶制品生产中的的运用.探讨了一种具有灵活性和可扩展性的通用半自动系统的设计思想和方法,可以运用在与此类似的工业生产线上. 相似文献
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Closed-chamber transepidermal water loss measurement: microclimate, calibration and performance 总被引:1,自引:0,他引:1
R. E. Imhof † M. E. P. De Jesus‡ P. Xiao † L. I. Ciortea† E. P. Berg† 《International journal of cosmetic science》2009,31(2):97-118
The importance of transepidermal water loss (TEWL) as a measure of the skin barrier is well recognized. Currently, the open-chamber method is dominant, but it is increasingly challenged by newer closed-chamber technologies. Whilst there is familiarity with open-chamber characteristics, there is uncertainty about the capabilities of the challengers. The main issues are related to how microclimate affects TEWL measurements.
The aim of this paper is to provide a framework for understanding the effects of microclimate on TEWL measurement. Part of the problem is that TEWL measurement is indirect. TEWL is the diffusion of condensed water through the stratum corneum (SC), whereas TEWL methods measure water vapour flux in the air above the SC. This vapour flux depends on (i) the rate of supply of water to the skin surface and (ii) the rate of evaporation of water from the skin surface. Rate (i) is a skin property (TEWL), rate (ii) is a microclimate property. The controlling rate for the combined process is the lower of the above two rates. Therefore, TEWL instruments measure TEWL only when TEWL is the rate-limiting process.
Another problem is that SC barrier property and SC hydration are affected by the microclimate adjacent to the skin surface. This is discussed insofar as it affects the measurement of TEWL. The conclusion is that such changes occur on a timescale that is long compared with TEWL measurement times.
An important aspect of TEWL measurement is calibration. We present an analysis of the traditional wet-cup method and a new droplet method that is traceable and has been independently verified by a standards laboratory.
Finally, we review performance indicators of commercial closed-chamber instruments with reference to open-chamber instruments. The main findings are that TEWL readings correlate well, but there are significant differences in the other aspects of performance. 相似文献
The aim of this paper is to provide a framework for understanding the effects of microclimate on TEWL measurement. Part of the problem is that TEWL measurement is indirect. TEWL is the diffusion of condensed water through the stratum corneum (SC), whereas TEWL methods measure water vapour flux in the air above the SC. This vapour flux depends on (i) the rate of supply of water to the skin surface and (ii) the rate of evaporation of water from the skin surface. Rate (i) is a skin property (TEWL), rate (ii) is a microclimate property. The controlling rate for the combined process is the lower of the above two rates. Therefore, TEWL instruments measure TEWL only when TEWL is the rate-limiting process.
Another problem is that SC barrier property and SC hydration are affected by the microclimate adjacent to the skin surface. This is discussed insofar as it affects the measurement of TEWL. The conclusion is that such changes occur on a timescale that is long compared with TEWL measurement times.
An important aspect of TEWL measurement is calibration. We present an analysis of the traditional wet-cup method and a new droplet method that is traceable and has been independently verified by a standards laboratory.
Finally, we review performance indicators of commercial closed-chamber instruments with reference to open-chamber instruments. The main findings are that TEWL readings correlate well, but there are significant differences in the other aspects of performance. 相似文献
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Anite Systems Space and Defence Division is a mature organization, certified to ISO 9001 standards and possesses considerable experience in the application of the European Space Agency (ESA) Software Engineering Standards to major software systems development. We have been selected by the European Commission to perform a Process Improvement Experiment (PIE) under its European Systems and Software Initiative (ESSI). The project is entitled ASTERIX - Automated Software Testing for Enhanced Reliability In Execution. The project's objective is to determine how greater attention to system-level testing can improve software product quality whilst reducing overall costs as measured across the full software development lifecycle (including extended warranty periods). The project is scheduled to run from early 1997 to late 1998.This paper is the project's Interim Dissemination deliverable providing details on project progress to date. It highlights the benefits the project's results will bring to the Software Quality, Process Improvement, and Space Software communities. 相似文献
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