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对称电容谐振式高压直流装置送能系统 被引量:1
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作者 高阳 高冲 +4 位作者 林畅 李栋 贺之渊 寇龙泽 刘栋 《电力自动化设备》 EI CSCD 北大核心 2021年第2期104-110,共7页
高电位驱动电路的送能系统是保证混合式直流断路器稳定工作的关键设备。与目前"磁隔离"送能原理不同,利用电容器"隔直通交"特性和LC电路串联谐振原理,提出一种对称电容谐振式高压直流装置送能系统,实现了地电位侧... 高电位驱动电路的送能系统是保证混合式直流断路器稳定工作的关键设备。与目前"磁隔离"送能原理不同,利用电容器"隔直通交"特性和LC电路串联谐振原理,提出一种对称电容谐振式高压直流装置送能系统,实现了地电位侧电能向高电位直流侧装置的高效传输。分析了该送能系统的工作原理,并针对该拓扑结构提出了电路参数设计原则和设计方法以及若干衍生拓扑结构。通过仿真对具体算例进行验证,仿真结果表明在直流故障工况下该送能系统仍然可以稳定工作,进而验证了所提新型送能系统的可行性和可靠性。 展开更多
关键词 高压直流装置 高压直流断路器 送能系统 LC串联谐振 拓扑结构
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Teleportation Capability of Six-Qubit Cluster State 被引量:2
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作者 查新未 宋海洋 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第12期1007-1009,共3页
Recently Wei-Bo Gao et al.[Phys.Rev.Lett.104 (2010) 020501]; reported on the creation of a 4-photon6-qubit cluster state.It is shown this states can be utilized for perfect teleportation of arbitrary three qubit syste... Recently Wei-Bo Gao et al.[Phys.Rev.Lett.104 (2010) 020501]; reported on the creation of a 4-photon6-qubit cluster state.It is shown this states can be utilized for perfect teleportation of arbitrary three qubit systemsand controlled teleportation of an arbitrary two-qubit state.Therefore, the six-qubit cluster state as quantum channelsis equivalent to that of maximally six-qubit entangled state. 展开更多
关键词 six-qubit cluster state TELEPORTATION controlled teleportation
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New Approach to the Delivery of Construction in Botswana
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作者 Aderemi Adeyemi Pasis Mselle +1 位作者 Dean Kashiwagi Jacob Kashiwagi 《Journal of Civil Engineering and Architecture》 2011年第7期606-617,共12页
The construction industry in Botswana has been identified as an industry with many problems. Currently the Botswana government uses the design-bid-build process, using prequalification and awards to the lowest bidder ... The construction industry in Botswana has been identified as an industry with many problems. Currently the Botswana government uses the design-bid-build process, using prequalification and awards to the lowest bidder for construction services. The government can also use the design-build delivery system. The current delivery system uses an engineering group that delivers designs and construction, uses a procurement group to award the contract and contract modifications. However, the analysis for all actions is done by the engineering group. The model is very similar to the Corps of Engineers traditional processes in the United States. Construction performance (on time and no contract deviations) has not been good. The authors propose that the delivery system and the paradigm of direction, control and decision making by the engineering group causes risk to the project and results in poor contractor performance. The authors suggest making modifications in the process and to use the design-build process. The authors also propose to change the paradigm using best value PIPS/IMT concepts. 展开更多
关键词 Botswana procurement new PM model paradigm change.
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Is the Culture or Unstable Procurement System Causing Nonperforming Projects?
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作者 Dean Kashiwagi Jacob Kashiwagi +1 位作者 Pasis Mselle Aderemi Adeyemi 《Journal of Civil Engineering and Architecture》 2011年第5期389-401,共13页
A research group at the University of Botswana has been investigating how culture and construction delivery system stability affect the Botswana construction industry performance. The government of Botswana is attempt... A research group at the University of Botswana has been investigating how culture and construction delivery system stability affect the Botswana construction industry performance. The government of Botswana is attempting to increase the construction performance and sustainability of the Botswana construction industry in an environment of local contractors who do not seem to have the expertise and experience. Currently, the Botswana industry is heavily dependent on foreign contractors. The researchers are trying to identify if the problem is the underdeveloped industry and Botswana culture, or potentially the combination of culture and unstable delivery system, and can a stable delivery system raise the performance of Botswana contractors. The two potential areas of interest are the country culture, and the project delivery/management model. The authors are using deductive logic, logical and simplistic models, and dominant or extreme information to minimizing the need to get into a long drawn out study of details which may be difficult to obtain and not necessarily solve the issue. The objective of the paper is to identify the best method to increase the performance of the construction industry, addressing both the cultural and delivery system problems. The preliminary measurement of the success of the solution is the acceptance of the concepts by major users in Botswana. This paper will propose the potential solution, which will be tested starting January 2011. If this solution is valid, it has a tremendous potential in underdeveloped countries. 展开更多
关键词 CULTURE project management Botswana.
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Simulation of natural gas transmission pipeline network system performance
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作者 Abraham Debebe Woldeyohannes Mohd Amin Abd Majid 《Journal of Energy and Power Engineering》 2009年第12期29-38,共10页
Simulation has proven to be an effective tool for analyzing pipeline network systems (PNS) in order to determine the design and operational variables which are essential for evaluating the performance of the system.... Simulation has proven to be an effective tool for analyzing pipeline network systems (PNS) in order to determine the design and operational variables which are essential for evaluating the performance of the system. This paper discusses the use of simulation for performance analysis of transmission PNS. A simulation model was developed for determining flow and pressure variables for different configuration of PNS. The mathematical formulation for the simulation model was derived based on the principles of energy conservation, mass balance, and compressor characteristics. For the determination of the pressure and flow variables, solution procedure was developed based on iterative Newton Raphson scheme and implemented using visual C++6. Evaluations of the simulation model with the existing pipeline network system showed that the model enabled to determine the operational variables with less than ten iterations. The performances of the compressor working in the pipeline network system xvhich includes energy consumption, compression ratio and discharge pressure were evaluated to meet pressure requirements ranging from 4000-5000 kPa at various speed. Results of the analyses from the simulation indicated that the model could be used for performance analysis to assist decisions regarding the design and optimal operations of transmission PNS. 展开更多
关键词 ENERGY transmission pipeline network: compressor station: natural gas: simulation
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