Axial offset control of PWR nuclear reactor core using intelligent techniques

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.     

办公室防辐射7杯美味OL养生香茶

干燥的气候让爱美的MM叫苦连连,整日躲在办公室里的OL们面对着电脑辐射更为补水养颜忙,一杯水接着一杯水,虽有效果但是却不明显。如果补水的同时也能起到养颜润肤的效果,该是多一举两得的事情。     

采用双向偏置曝光的成像干涉光刻技术

成像干涉光刻技术(IIL)具有干涉光刻技术(IL)的高分辨力和光学光刻技术(OL)产生任意形状集成电路特征图形的能力。在IIL中,按掩模图形的不同空间频率成份分区曝光,并使其在抗蚀剂基片上非相干叠加,得到高分辨抗蚀剂图形。本文在研究一般三次曝光IIL原理基础上,提出采用沿X轴正、负方向以及沿Y轴正、负方向偏置的双向偏置照明,分别曝光 X方向、-X方向、 Y方向、-Y方向的高空间频率分量并与垂直于掩模方向的低空间频率分量曝光相结合的五次曝光IIL。理论和计算模拟表明,该方法可以提高图形对比度和分辨力,并减小因调焦误差引起的图形横向位移误差,有利于改善抗蚀剂图形质量。     

PowerBuilder中图片文件的处理

文章总结了在ＰｏｗｗｅｒＢｕｉｌｄｅｒ应用程序中处理图片文件的两种方法,ＰｏｗｅｒＢｕｉｌｇｄｅｒ语句加Ｐｉｅｔｕｒｅｒ控件以及ＯＬＥ列加ＯＬＥ控件。作者从图片的存储。显示民族 三方面对这两种方法进行了徼讨论。     

神经网络短期负荷预测输入变量选择新方法

输入变量选择是神经网络建模前的一项重要工作,是否能够选择出一组最能反映期望输出变化原因的输入变量直接关系到神经网络预测的性能。文中将正交最小二乘(OLS)法应用于神经网络短期负荷预测的输入变量选择。以南京地区1998年、1999年夏季日最大负荷预测为例,对比了OLS法与相关系数法的输入变量选择结果。结果显示OLS法可以得到更小、更准确的输入变量集,神经网络的收敛速度更快,预测结果也更好,从而验证了该方法的有效性。     

A graphical design method for reaction–extraction processes in quaternary systems

This paper proposes a graphical design method for quaternary systems in simultaneous chemical and physical liquid–liquid equilibrium (reaction–separation process). The reactive phase equilibrium data and the stage by stage calculation are represented into two projections diagrams with rectangular coordinates. The graphical method has been applied to reversible reactive systems where all of the components of the reaction have the same stoichiometric coefficient. This graphical method allows estimating the number of reactive theoretical stages, the limits of the solvent to feed ratio (D/F), the extent of reaction and the conversion. Results obtained for seven design problems (involving four different reactive systems) are in good agreement with state of the art simulation software and with literature.     

Biochemistry Department,University of Oxford

Howard Watson describes how Hawkins\Brown's new Biochemistry Department for the University of Oxford represents an innovative new model for scientific research institutes. Spatially, its interior not only positively embraces and encourages social interaction and the fertilisation of ideas, but also brings art, architecture and science together under a single roof. Copyright © 2009 John Wiley & Sons, Ltd.     

BG2003 释光谱仪

介绍了新型BG2003释光谱仪。它在对同一结晶固体进行热释光和光释光测定时．可选择性地使用光释光和／热释光来达到目的。可获得释光过程图和释光光谱图．获得有关样品的释光信息。     

Indian parallelism on unary ol systems

In this paper we impose the Indian parallelism restriction on the unary developmental system, i. e. on UOL system. We observe that corresponding to any P_aUL language we can get a unary language of Restricted parallel content free language (RP_aCLUL).

Section 1 deals with definitions and Section 2 deals with some propoerties of P_aUL systems. In Section 3, we compare P_aUL language with unary languages of parallel content free grammars and also characterize some subfamilies of P_aUL languages. In the last section, we state a few hierarchial and closure properties.     

An improved artificial bee colony optimization algorithm based on orthogonal learning for optimal power flow problem

The increasing fuel price has led to high operational cost and therefore, advanced optimal dispatch schemes need to be developed to reduce the operational cost while maintaining the stability of grid. This study applies an improved heuristic approach, the improved Artificial Bee Colony (IABC) to optimal power flow (OPF) problem in electric power grids. Although original ABC has provided robust solutions for a range of problems, such as the university timetabling, training neural networks and optimal distributed generation allocation, its poor exploitation often causes solutions to be trapped in local minima. Therefore, in order to adjust the exploitation and exploration of ABC, the IABC based on the orthogonal learning is proposed. Orthogonal learning is a strategy to predict the best combination of two solution vectors based on limited trials instead of exhaustive trials, and to conduct deep search in the solution space. To assess the proposed method, two fuel cost objective functions with high non-linearity and non-convexity are selected for the OPF problem. The proposed IABC is verified by IEEE-30 and 118 bus test systems. In all case studies, the IABC has shown to consistently achieve a lower cost with smaller deviation over multiple runs than other modern heuristic optimization techniques. For example, the quadratic fuel cost with valve effect found by IABC for 30 bus system is 919.567 $/hour, saving 4.2% of original cost, with 0.666 standard deviation. Therefore, IABC can efficiently generate high quality solutions to nonlinear, nonconvex and mixed integer problems.