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991.
简要介绍了赢得值原理的一些基本概念及其在设计项目管理中的作用.重点介绍了该原理在洛阳石油化工工程公司总承包的1.0 Mt/a延迟焦化装置设计进度控制中的应用.通过综合控制ACWP, BCWP二条曲线与BCWS曲线的偏差使其平稳紧密上升,可成功地对项目成本和进度进行偏差分析、纠偏控制及趋势预测.总结了赢得值在设计项目管理成本/进度控制应用中的重点和难点. 相似文献
992.
New small‐scale dispersed generation systems, such as fuel cells and micro gas turbines, have made remarkable advances lately and they will be applied practically in the near future. Although a large number of researches on the introduction of small‐scale dispersed generation systems have been carried out, only a small number of small‐scale dispersed generation systems are considered in these researches. Therefore, little is known about problems to be solved when a large number of small‐scale dispersed generation systems are introduced into electric power systems. This paper deals with a super‐distributed energy system that consists of a great number of dispersed generation systems such as fuel cells, micro gas turbines, and so on. The behavior of a customer with a dispersed generation system is simulated as the Ising model in statistical mechanics. The necessity of a distribution network in super‐distributed energy systems is discussed based on the Ising model. The feasibility of decentralized autonomous control using vicinity information is also investigated on the basis of stability analysis of the Hopfield neural network model. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 151(1): 43–55, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10368 相似文献
993.
传统的干燥控制系统思维方式是把干燥流程看成是一个大的惯性场,以惯性的形态看待与过程相关的数据,对输入参数的过程实时性很少研究,这样的结果就是控制准确性、精确度与实际过程的吻合程度较差。拟从干燥系统输入体系的结构入手,采用时序分析的手法对入粮到干燥的传输时序进行解析,推理出动态实时数据模型。 相似文献
994.
Bong-Un Lee Hwa-Suk Oh Ja-Young Kang 《Journal of Mechanical Science and Technology》2007,21(3):436-447
The geometric singularity problem is one of principal difficulty when using single-gimbal control moment gyros as spacecraft
attitude control devices. To overcome singularity, new steering logics are suggested in this paper which results in a reduction
in the difficulty of generating gimbal rates around a singular state. One of the suggested steering laws presented is the
reduced dimensional singular value decomposition steering law, which adopts the singular value decomposition in reduced dimensional
forms. Two other steering laws make use of the least square method in reduced dimensional forms. All of the suggested steering
laws have been generated for the compensation of the torque insufficiency. These logics are verified mathematically and simulations
at a singular condition and non-singular condition are performed to see how well they work. 相似文献
995.
Verbruggen Frederick; Liefooghe Baptist; Vandierendonck André; Demanet Jelle 《Canadian Metallurgical Quarterly》2007,33(2):342
In the task-switching literature, it has frequently been demonstrated that although advance task preparation reduces the switch cost, it never really eliminates the switch cost. This remaining residual switch cost received much attention, and it has been argued that advance preparation is restricted in nature. In the present study, the role of task-cue presentation in the establishment of the residual switch cost was investigated. In 4 experiments, the cue was removed during the preparation interval, and it was hypothesized that this would encourage participants to complete advance task preparation. The results of all 4 experiments provided support for this hypothesis: When the cue was presented for a short time and then removed, the residual switch cost completely disappeared. This was found for different cue types. Furthermore, Experiment 3 demonstrated that it was not the presence of the cue itself but merely differences in advance task preparation that caused the effects. This suggests that advance task preparation is not as restricted in nature as previously assumed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
996.
埕岛油田馆陶组油藏调剖技术初探 总被引:2,自引:0,他引:2
讨论了埕岛油田注水井调剖中施工场地、调剖剂配制水选择以及井下防砂管等因素对调剖施工方式的影响。分析了多种类型调剖剂的适应性,筛选出冻胶类调剖剂作为埕岛油田的调剖剂。研制出由改性HPAM为主剂、Cr3 有机络合物为交联剂和以金属络合物为主的交联稳定剂组成的HST-1型海水基冻胶调剖剂,并用于CB251A-6井调剖,取得了良好效果。探索出了一套适用于埕岛油田不动管柱、海水配制调剖剂和采用船载施工设备进行现场施工的注水井调剖工艺。 相似文献
997.
本文主要从选择卡伦水库实行洪水风险调度的依据、水库洪水控制标准、调度原则及效益等方面论述卡伦水库实行洪水风险调度的重大意义。特别强调在水库洪水调度过程中适度承担风险,必须确保工程安全运行、科学调度,加强管理,依法防洪,合理蓄水,要正确把握水库安全度汛与水资源合理利用的关系,正确处理防洪与兴利的关系,正确处理风险与效益的关系,充分发挥水库的综合效益。适度承担风险进行水库洪水调度,既充分利用雨洪资源,又尽最大可能变水害为水利,实现雨洪资源化,达到人、水与自然和谐共处,促进经济社会协调发展。 相似文献
999.
1000.
Manabu Ishitobi Takeshi Myoi Koji Soshin Eiji Hiraki Mutsuo Nakaoka 《Electrical Engineering in Japan》2005,153(3):79-87
This paper presents a single lossless inductive snubber‐assisted ZCS‐PFM series resonant DC‐DC power converter with a high‐frequency high‐voltage transformer link for industrial‐use high‐power magnetron drive. The current flowing through the active power switches rises gradually at a turned‐on transient state with the aid of a single lossless snubber inductor, and ZCS turn‐on commutation based on overlapping current can be achieved via the wide range pulse frequency modulation control scheme. The high‐frequency high‐voltage transformer primary side resonant current always becomes continuous operation mode, by electromagnetic loose coupling design of the high‐frequency high‐voltage transformer and the magnetizing inductance of the high‐frequency high‐voltage transformer. As a result, this high‐voltage power converter circuit for the magnetron can achieve a complete zero current soft switching under the condition of broad width gate voltage signals. Furthermore, this high‐voltage DC‐DC power converter circuit can regulate the output power from zero to full over audible frequency range via the two resonant frequency circuit design. Its operating performances are evaluated and discussed on the basis of the power loss analysis simulation and the experimental results from a practical point of view. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(3): 79–87, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20126 相似文献