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991.
Man Gyun Na Sun Ho Shin Dong Won Jung Soong Pyung Kim Ji Hwan Jeong Byung Chul Lee 《Nuclear Engineering and Design》2004,232(3):267-300
In this work, a probabilistic neural network (PNN) that has been applied well to the classification problems is used in order to identify the break locations of loss of coolant accidents (LOCA) such as hot-leg, cold-leg and steam generator tubes. Also, a fuzzy neural network (FNN) is designed to estimate the break size. The inputs to PNN and FNN are time-integrated values obtained by integrating measurement signals during a short time interval after reactor scram. An automatic structure constructor for the fuzzy neural network automatically selects the input variables from the time-integrated values of many measured signals, and optimizes the number of rules and its related parameters. It is verified that the proposed algorithm identifies very well the break locations of LOCAs and also, estimate their break size accurately. 相似文献
992.
HONG Xianlong MA Yuchun DONG Sheqin CAI Yici Chung-Kuan Cheng & GU JunDepartment of Computer Science Technology Tsinghua University Beijing China Department of Computer Science Engineering University of California San Diego La Jolla CA - USA Department of Computer Science Science Technology University of Hong Kong 《中国科学F辑(英文版)》2004,47(1):1-19
Floorplanning is a critical phase in physical design of VLSI circuits. The stochastic optimization method is widely used to handle this NP-hard problem. The key to the floorplanning algorithm based on stochastic optimization is to encode the floorplan structure properly. In this paper, corner block list (CBL)-a new efficient topological representation for non-slicing floorplan-is proposed with applications to VLSI floorplan. Given a corner block list, it takes only linear time to construct the floorplan. In floorplanning of typical VLSI design, some blocks are required to satisfy some constraints in the final packing. Boundary constraint is one kind of those constraints to pack some blocks along the pre-specified boundaries of the final chip so that the blocks are easier to be connected to certain I/O pads. We implement the boundary constraint algorithm for general floorplan by extending CBL. Our contribution is to find the necessary and sufficient characterization of the blocks along the boundary repre 相似文献
993.
This paper addresses the problem of local state feedback stabilization of a class of nonlinear systems, which have planar centre manifold. A new technique for designing centre manifold has been developed. Using this approach, a sufficient condition for stabilization of a class of nonlinear system is obtained. The approach has been specified for two particular critical cases: ‘zero centre’ with zero eigenvalue of multiplicity 2 and ‘oscillatory centre’ with a pair of pure imaginary eigenvalues. The control law, which stabilizes the overall system, is also presented. Some examples are presented to indicate how the present theorem may be implemented. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
994.
针对硝酸机组的工艺特点及其技术要求,基于PLC可编程控制器技术,实现了化工机组生产过程监控的自动化撞制系统。讨论了由现场级、PLC控制级和HM1监控级3层结构组成的自动化控制系统的结构、功能和控制方法。用防喘振控制模式、启停车控制逻辑模式及PlD回路控制实现了机组控制的目标。所完成的控制系统成功地应用于安徽化工10^5t稀硝酸机组控制系统,实现了机组运行过程的实时监控、防喘振控制和启停车联锁逻辑等功能,取得了明显的成效。 相似文献
995.
996.
Dong Ho Bae Chul Han Kim Seon Young Cho Jung Kyun Hong Chon Liang Tsai 《Journal of Mechanical Science and Technology》2002,16(9):1054-1064
Numerical prediction of welding-induced residual stresses using the finite element method has been a common practice in the
development or refinement of welded product designs. Various researchers have studied several thermal models associated with
the welding process. Among these thermal models, ramp heat input and double-ellipsoid moving source have been investigated.
These heat-source models predict the temperature fields and history with or without accuracy. However, these models can predict
the thermal characteristics of the welding process that influence the formation of the inherent plastic strains, which ultimately
determines the final state of residual stresses in the weldment. The magnitude and distribution of residual stresses are compared.
Although the two models predict similar magnitude of the longitudinal stress, the double-ellipsoid moving source model predicts
wider tensile stress zones than the other one. And, both the ramp heating and moving source models predict the stress results
in reasonable agreement with the experimental data. 相似文献
997.
采用直流电弧等离子体法 ,分别在 1个大气压的H2 +Ar和CH4+He混和气氛中制备了Fe、Ni、Fe-Ni合金磁性超微粒子 (UFP)。利用Fe、Ni、Fe-Ni合金超微粒子 ,选择适当的表面活性剂和载液 ,制备了高粘度磁性液体(ML) ,常温 (2 5℃ )粘度为 (2 6~ 6 0 )× 10 5mPa·s,高温 (85℃ )粘度为 (1 0~ 3 2 )× 10 5mPa·s,室温下饱和磁化强度为FeML 2 4 0 8~ 6 8 0 0Am2 /kg,NiML 10 19~ 17 83Am2 /kg,Fe-NiML 2 6 2 1~ 75 13Am2 /kg 相似文献
998.
999.
用工业个人计算机(IPC)开发CNC系统具有很多的优越性。本文主要介绍了基于IPC的CNC系统的硬件和软件妈及一些关键问题的解决措施。该系统已经与某型加工中心机床联调试切成功. 相似文献
1000.