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A Feasible Zone Analysis Method with Global Partial Load Scanning for Solving Power Flow Coupling Models of CCHP Systems

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Journal of Modern Power Systems and Clean Energy 2022年第2期10卷 371-377页

作者： Pohan Chen kai sun Chenghui Zhang Bo sun the Department of Electrical Engineering Tsinghua UniversityBeijingChina the School of Control Science and Engineering Shandong UniversityJinanChina

Heat exchanger systems(HXSs)or heat recovery steam generators(HRSGs)are commonly used in 100 kW to 50 MW combined cooling,heating,and power(CCHP)*** flow coupling(PFC)is found in HXSs and is complex for researchers to *** could possibly mislead the dispatch schedule and result in the inaccurate *** is caused by the inlet and outlet temperatures of each component,gas flow pressure variation,conductive medium flow rate,and atmosphere condition *** this paper,the expression of PFC is built by using quadratic functions to fit the non!inearit>of thermal *** fitting the model,the environmental condition needs prediction,which is calculated using phase space reconstruction(PSR)Kalman *** order to solve the complex quadratic dispatch model,a hybrid following electricity load(FEL)and following thermal load(FTL)mode for reducing the dimension of dispatch model,and a feasible zone analysis(FZA)method are *** a result,the PFC problem of CCHP system is solved,and the dispatch cost,investment cost,and the maximum power requirements are *** this paper,a case in Jinan,China is *** PFC model is proven to be more precise and accurate compared with traditional models.

关键词： Combined cooling heating and power(CCHP)system renewable energy source(RES) load prediction operation strategy exergy and energy analysis power flow coupling(PFC)model.

Optimal control of a spacecraft with deployable solar arrays using particle swarm optimization algorithm

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Science China(Technological Sciences) 2011年第5期54卷 1107-1112页

作者： GE XinSheng sun kai College of Mechanical & Electrical Engineering Beijing Information Science & Technology University Beijing 100192 China Department of Mechanics Peking University Beijing 100871 China

The optimal control problem of the multibody dynamics of a spacecraft in space, modeled as a central body with one-sided connected deployable solar arrays, is investigated. The dynamical equations of motion of the spacecraft with solar arrays are derived using the multibody dynamics method. The control of the attitude motion of a spacecraft system can be transformed into the motion planning problem of nonholonomic system when the initial angular momentum is zero. These are then used to investigate the motion planning of the spacecraft during solar arrays deployment via particle swarm optimization (PSO) and results are obtained with the optimal control input and the optimal trajectory. The results of numerical simulation show that this approach is effective for the control problem of the attitude of a spacecraft during the deployment process of its solar arrays.

关键词： multibody spacecraft attitude dynamics optimal control particle swarm optimization

Location methods of oscillation sources in power systems: a survey

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Journal of Modern Power Systems and Clean Energy 2017年第2期5卷 151-159页

作者： Bin WANG kai sun University of Tennessee Knoxville TN 37996 USA

The deployment of a synchrophasor-based widearea measurement system(WAMS) in a power grid largely improves the observability of power system dynamics and the operator’s real-time situational awareness for potential stability issues. The WAMS in many power grids has successfully captured system oscillation events, e.g. poorly damped natural oscillations and forced oscillations, from time to time. To identify the root cause of an observed oscillation event for further mitigation actions, many methods have been proposed to locate the source of oscillation based on different ideas and principles. However, most methods proposed so far for locating the oscillation source in a power grid are not reliable enough for practical applications. This paper presents a comprehensive review of existing location methods, which basically fall into four major categories, plus a few other methods. Their advantages and disadvantages are discussed in detail. Some trends and challenges on the problem of oscillation source location are pointed out along with potential future research directions. Finally, a practical, general scheme for oscillation source location using available location methods is suggested and analyzed.

关键词： Power oscillation Oscillation source location Traveling wave Damping torque Mode shape Transient energy Oscillation test cases library

Evolvable dialogue state tracking for statistical dialogue management

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Frontiers of Computer Science 2016年第2期10卷 201-215页

作者： kai YU Lu CHEN kai sun Qizhe XIE Su ZHU Key Laboratory of Shanghai Education Commission for Intelligent Interaction and Cognitive EngineeringSpeechLab Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China Department of Computer Science Cornell University Ithaca NY 14853 USA

Statistical dialogue management is the core of cognitive spoken dialogue systems （SDS） and has attracted great research interest. In recent years, SDS with the ability of evolution is of particular interest and becomes the cuttingedge of SDS research. Dialogue state tracking （DST） is a process to estimate the distribution of the dialogue states at each dialogue turn, given the previous interaction history. It plays an important role in statistical dialogue management. To provide a common testbed for advancing the research of DST, international DST challenges （DSTC） have been organised and well-attended by major SDS groups in the world. This paper reviews recent progresses on rule-based and statistical approaches during the challenges. In particular, this paper is focused on evolvable DST approaches for dialogue domain extension. The two primary aspects for evolution, semantic parsing and tracker, are discussed. Semantic enhancement and a DST framework which bridges rule-based and statistical models are introduced in detail. By effectively incorporating prior knowledge of dialogue state transition and the ability of being data-driven, the new framework supports reliable domain extension with little data and can continuously improve with more data available. This makes it excellent candidate for DST evolution. Experiments show that the evolvable DST approaches can achieve the state-of-the-art performance and outperform all previously submitted trackers in the third DSTC.

关键词： dialogue management domain extension,evolvable dialogue state tracking parser tracker

Metal-free tetra-n-butylammonium bromide-mediated aerobic oxidative synthesis of β-ketosulfones from styrenes

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Science China Chemistry 2017年第3期60卷 353-357页

作者： Xin Wan kai sun Guisheng Zhang College of Chemistry and Chemical Engineering Anyang Normal University School of Chemistry and Chemical Engineering Henan Normal University

An efficient and broadly applicable protocol for the aerobic coupling of styrenes with sulfonylhydrazides has been developed that affords P-ketosulfones bearing various functional groups in moderate to excellent *** preliminary experimental results support the involvement of active benzyl radical species,and a radical pathway was therefore proposed for the reaction.

关键词： styrenes aerobic difunctionalization ketosulfones transition metal-free conditions

Distance Distribution and Reliability of Small-World Networks

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Chinese Physics Letters 2001年第3期18卷 452-454页

作者： sun kai OUYANG Qi Department of Physics and Mesoscopic Physics Laboratory Peking UniversityBeijing 100871

We have studied the distribution of distances in small-world network by computer *** found that in a small world network,the longest distance between two vertices is just slightly longer than the average distance,indicating that the efficiency of the network is absolute rather than in *** also investigated the robustness of a small-world network by randomly cutting some long paths in the *** results show that the network is reliable against random cutting.

关键词： absolute slightly Reliability

Copper-catalyzed arenes amination with saccharins

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Science China Chemistry 2015年第8期58卷 1354-1358页

作者： kai sun Yan Li Qian Zhang College of Chemistry and Chemical Engineering Anyang Normal University Department of Chemistry Northeast Normal University

A novel copper-catalyzed direct C–N formation reaction of simple arenes with cheap and pharmacological saccharin derivatives under relatively mild conditions was developed with arenes as limiting *** work provided a ... 详细信息

关键词： aromatic amines C-N bond formation arenes saccharins arenes as limiting reagents

A review on applications of holomorphic embedding methods

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iEnergy 2023年第4期2卷 264-274页

作者： kaiyang Huang kai sun Department of Electrical Engineering and Computer Science University of TennesseeKnoxvilleTN 37996USA

The holomorphic embedding method(HEM)stands as a mathematical technique renowned for its favorable convergence properties when resolving algebraic systems involving complex *** key idea behind the HEM is to convert the task of solving complex algebraic equations into a series expansion involving one or multiple embedded complex *** transformation empowers the utilization of complex analysis tools to tackle the original problem *** the 2010s,the HEM has been applied to steady-state and dynamic problems in power systems and has shown superior convergence and robustness compared to traditional numerical *** paper provides a comprehensive review on the diverse applications of the HEM and its variants reported by the literature in the past *** paper discusses both the strengths and limitations of these HEMs and provides guidelines for practical *** also outlines the challenges and potential directions for future research in this field.

关键词： Holomorphic embedding method power flow polynomial solutions nonlinear algebraic equations differential equations

A deterministic FE contact analysis of 3D rough surfaces with textures and comparison with classic statistical contact models

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Science China(Technological Sciences) 2021年第2期64卷 297-316页

作者： ZHANG Rui MENG XiangHui LYU BuGao sun kai School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China AECC Commercial Aircraft Engine Company Limited Shanghai 200241China

Accurate contact calculations of real rough surfaces are fundamental but complicated. The model-based methods are convenient and straightforward. But these methods ignore some factors and may lead to less accurate results. This is especially true when considering multi-scale topographic features of engineering rough surfaces. Based on artificially generated rough surfaces, the deterministic contact analysis of two 3D rough surfaces is conducted by the finite element method(FEM). The calculations show that when the separation between surfaces reduces, results of classic model-based methods are quite different from those of this study, especially when the roughness distribution and textures are considered. As friction pairs are working under increasing harsh conditions, the accurate contact calculation in this paper will be of great significance.

关键词： deterministic contact analysis multi-scale topography finite element method(FEM) engineering rough surfaces