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Optimize performance of a diffractive neural network by controlling the Fresnel number

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Photonics Research 2022年第11期10卷 2667-2676页

作者： minjia zheng LEI SHI JIAN ZI State Key Laboratory of Surface Physics Key Laboratory of Micro-and Nano-Photonic Structures(Ministry of Education)and Department of PhysicsFudan UniversityShanghai 200433China Institute for Nanoelectronic Devices and Quantum Computing Fudan UniversityShanghai 200433China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

To achieve better performance of a diffractive deep neural network, increasing its spatial complexity(neurons and layers) is commonly used. Subject to physical laws of optical diffraction, a deeper diffractive neural network(DNN) would be more difficult to implement, and the development of DNN is limited. In this work, we found controlling the Fresnel number can increase DNN’s capability of expression and its spatial complexity is even *** with only one phase modulation layer was proposed and experimentally realized at 515 nm. With the optimal Fresnel number, the single-layer DNN reached a maximum accuracy of 97.08% in the handwritten digits recognition task.

关键词： Fresnel controlling number

含抽水蓄能电站的输电线路扩展规划启发式算法

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电工技术 2024年第3期 12-15页

作者：李逸欣吴伟杰左郑敏郑敏嘉陈逸鹏广东电网有限责任公司电网规划研究中心广东广州510000 中国能源建设集团广东省电力设计研究院有限公司广东广州510663

针对含抽水蓄能电站的输电线路规划中存在的非线性和非凸问题,提出了一种基于MILP的输电线路扩展规划启发式算法。首先将混合整数线性问题(MILP)传输扩展规划(TEP)模型的精确解与元启发式算法的随机解相结合;然后引入了基于MILP的启发(M... 详细信息

针对含抽水蓄能电站的输电线路规划中存在的非线性和非凸问题,提出了一种基于MILP的输电线路扩展规划启发式算法。首先将混合整数线性问题(MILP)传输扩展规划(TEP)模型的精确解与元启发式算法的随机解相结合;然后引入了基于MILP的启发(MBH)算法来解决线性近似和元启发式过程中出现的问题;最后在IEEE RTS-24节点测试系统的单阶段TEP验证了所提出算法的有效性。

关键词：输电扩展规划元启发式混合整数线性问题线性近似

“双碳”背景下“下库结合”抽水蓄能电站开发模式研究

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水利发展研究 2024年第4期24卷 92-96页

作者：张伊宁吴伟杰邓雪原李逸欣郑敏嘉左郑敏广东电网有限责任公司电网规划研究中心广东广州510220 广东省水利电力勘测设计研究院有限公司广东广州510630

抽水蓄能是新能源发展的重要组成部分,文章以茶坑站为例,探索了广东省“下库结合”抽水蓄能电站新开发模式。研究表明:(1)茶坑抽水蓄能电站是利用已建成的常规水电站水库做下库,在其上游新建上库,拟装机容量为28万kW的茶坑抽水蓄能电站... 详细信息

抽水蓄能是新能源发展的重要组成部分,文章以茶坑站为例,探索了广东省“下库结合”抽水蓄能电站新开发模式。研究表明:(1)茶坑抽水蓄能电站是利用已建成的常规水电站水库做下库,在其上游新建上库,拟装机容量为28万kW的茶坑抽水蓄能电站,是抽水蓄能电站建设模式的新探索。(2)茶坑抽水蓄能电站建成后,是对清远市电网安全经济运行的有力补偿,使系统调峰能力增强,并能更好地保证清远市风—光联合系统的稳定出力。(3)利用已建成的常规水电站兴建茶坑抽水蓄能电站,站址区域构造稳定性好,工程建设范围内不涉及生态保护红线,征(用)地面积3 682.77亩,茶坑抽水蓄能电站建设基本不存在制约工程建设的因素。本次提出的“下库结合”开发模式完善了抽水蓄能电站开发模式,可给利用已建成水库作为下库只需新建上库的抽水蓄能电站开发提供参考。

关键词：抽水蓄能电站下库结合开发模式高质量发展广东省

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Full description of dipole orientation in organic light-emitting diodes

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Chinese Optics Letters 2023年第2期21卷 92-98页

作者：范灵杰赵茂雄楚娇沈唐尧郑敏嘉关放殷海玮石磊资剑 Department of Physics Key Laboratory of Micro-and Nano-Photonic Structures(Ministry of Education)and State Key Laboratory of Surface PhysicsFudan UniversityShanghai 200433China Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication(SERCOM) Shanghai 200433China Institute for Nanoelectronic Devices and Quantum Computing Fudan UniversityShanghai 200438China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

Considerable progress has been made in organic light-emitting diodes(OLEDs)to achieve high external quantum efficiency,among which dipole orientation has a remarkable *** most cases,the radiation of the dipoles in OLEDs is theoretically predicted with only one orientation parameter to match with corresponding ***,we develop a new theory with three orientation parameters to fully describe the relationship between dipole orientation and power ***,we design an optimal test structure for measuring all three orientation *** three orientation parameters could be retrieved from non-polarized *** theory provides a universal plot of dipole orientations in OLEDs,paving the way for designing more complicated OLED devices.

关键词： organic light-emitting diodes dipole orientation Fourier series expansion

Plate tectonics in the Archean:Observations versus interpretations

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Science China Earth Sciences 2024年第1期67卷 1-30页

作者： YongFei zheng School of Earth and Space Sciences University of Science and Technology of ChinaHefei 230026China Key Laboratory of Crust-Mantle Materials and Environment Chinese Academy of SciencesHefei 230026China Center of Excellence for Comparative Planetology Chinese Academy of SciencesHefei 230026China

Plate tectonics theory,established in the 1960s,has been successful in explaining many geological phenomena,processes and events that occurred in the ***,the theory has often struggled to provide a coherent framework in interpreting geological records in continental interior and Precambrian *** dealing with the relationship between plate tectonics and continental geology,continental interior tectonics was often separated from continental margin tectonics in the inheritance and development of their structure and *** separation led to the illusion that the plate tectonics theory is not applicable to Precambrian geology,particularly in explaining the fundamental geological characteristics of Archean *** this illusion does not mean that the Archean continental crust did not originate from a regime of plate tectonics,it led to the development of alternative tectonic models,often involving vertical movements under a regime of stagnant lid tectonics,including not only endogenous processes such as gravitational sagduction,mantle plumes and heat pipes but also exogenous processes such as bolide *** vertical processes were not unique to the Archean but persisted into the *** result from mantle poloidal convection at different depths,not specific to any particular *** the plate tectonics theory from the traditional kinematic model in the 20th century to a holistic kinematic-dynamic model in the 21st century and systematically examining the vertical transport of matter and energy at plate margins,it is evident that plate tectonics can explain the common geological characteristics of Archean cratons,such as lithological associations,structural patterns and metamorphic *** deciphering the structure and composition of convergent plate margins as well as their dynamics,the formation and evolution of continental crust since the Archean can be divided into ancient plate tectonics in the Preca

关键词： Plate tectonics Archean geology Continental origin Crustal reworking Plate interior Plate margin

Discovery of the Significant Impacts of Swell Propagation on Global Wave Climate Change

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Journal of Ocean University of China 2024年第3期23卷 594-604页

作者： zheng Chongwei Dalian Naval Academy Dalian 116018China Marine Resources and Environment Research Group on the Maritime Silk Road Dalian 116018China

This study compared the differences in the wave climate in the South China Sea and North Indian Ocean under these two datasets:ERA-40 wave reanalysis and Mei’s hindcast wave *** the numerical calculation of regional ocean waves,the wave climate characteristics exhibited significant bias if the influence of external swells(swells from afar)was not fully considered,which may provide an incorrect basis for global climate change analysis.1)The trends of the significant wave height(SWH)obtained from the two datasets showed significant differences,such as those of the Bay of Bengal and the Java Sea in *** the past 45 years,SWH from ERA-40(SWH-ERA)exhibited a significant annual increase in low-latitude waters of the North Indian Ocean(0.2-0.6 cm yr^(-1))and South China Sea(0.2-0.8 cm yr^(-1)).2)In the Bay of Bengal,the SWH-ERA in each month was generally 0.5 m higher than the SWH from Mei’s hindcast wave data(SWH-Mei)and can reach 1.0 m higher in some months.3)In the Bay of Bengal,SWH-ERA and SWH-Mei increased significantly at annual rates of 0.13 and 0.27 cm yr^(-1),*** increasing trend was mainly reflected after ***-ERA showed a trough in 1975(1.33 m)and a crest in 1992(1.83 m),which were not reflected in SWH-Mei.

关键词： wave climate climatic trend monthly variation annual variation external swell

A positive trend in the stability of global offshore wind energy

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Acta Oceanologica Sinica 2024年第1期43卷 123-134页

作者： Chongwei zheng Dalian Naval Academy Dalian 116018China Marine Resources and Environment Research Group on the Maritime Silk Road Dalian 116018China Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of ChinaQingdao 266100China

The recognition on the trend of wind energy stability is still extremely rare,although it is closely related to acquisition efficiency,grid connection,equipment lifetime,and costs of wind energy *** the 40-year(1979–2018)ERA-Interim data from the European Center for Medium-Range Weather Forecasts,this study presented the spatial-temporal distribution and climatic trend of the stability of global offshore wind energy as well as the abrupt phenomenon of wind energy stability in key regions over the past 40 years with the climatic analysis method and Mann-Kendall(M-K)*** results show the following 5 points.(1)According to the coefficient of variation(C_(v))of the wind power density,there are six permanent stable zones of global offshore wind energy:the southeast and northeast trade wind zones in the Indian,Pacific and Atlantic oceans,the Southern Hemisphere westerly,and a semi-permanent stable zone(North Indian Ocean).(2)There are six lowvalue zones for both seasonal variability index(S_(v))and monthly variability index(M_(v))globally,with a similar spatial distribution as that of the six permanent stable zones.M_(v) and S_(v) in the Arabian Sea are the highest in the world.(3)After C_(v),M_(v) and S_(v) are comprehensively considered,the six permanent stable zones have an obvious advantage in the stability of wind energy over other sea areas,with C_(v) below 0.8,M_(v) within 1.0,and S_(v) within 0.7 all the year round.(4)The global stability of offshore wind energy shows a positive climatic trend for the past four decades.C_(v),M_(v) and S_(v) have not changed significantly or decreased in most of the global ocean during 1979 *** is,wind energy is flat or more stable,while the monthly and seasonal variabilities tend to shrink/smooth,which is beneficial for wind energy utilization.(5)C_(v) in the low-latitude Pacific and M_(v) and S_(v) in both the North Indian Ocean and the low-latitude Pacific have an obvious abrupt phenomenon at the end of

关键词： global oceans wind energy stability spatial-temporal distribution climatic trend

Wind power and sand/dust storms

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 175-176页

作者： XiaoJing zheng Center for Particle-Laden Turbulence Lanzhou UniversityLanzhou 730000China

Sand/dust storms,a globally prevalent catastrophic weather phenomenon,can cause significant erosion to the climate and ecological *** high concentration of sand particles they carry not only impacts atmospheric qualit... 详细信息

关键词： Wind power and sand/dust storms

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Damping Characteristic Analysis and Optimization of Wind-thermal-bundled Power Transmission by LCC-HVDC Systems

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 299-312页

作者： Liwen zheng Shiying Ma the Power System Department China Electric Power Research InstituteBeijing 100192China

With the rapid development of renewable energy,wind-thermal-bundled power transmission by line-commutated converter based high-voltage direct current(LCC-HVDC)systems has been widely *** dynamic interaction mechanisms among permanent magnet synchronous generators(PMSGs),synchronous generators(SGs),and LCC-HVDC system become *** deal with this issue,a path analysis method(PAM)is proposed to study the dynamic interaction mechanism,and the damping reconstruction is used to analyze the damping characteristic of the ***,based on the modular modeling,linearized models for the PMSG subsystem,the LCC-HVDC subsystem,and the SG subsystem are ***,based on the closed-loop transfer function diagram of the system,the disturbance transfer path and coupling relationship among subsystems are analyzed by the PAM,and the damping characteristic analysis of the SG-dominated oscillation mode is studied based on the damping *** with the PAM,the small-signal model of the system is obtained and eigenvalue analysis results are ***,the effect of the control parameters on the damping characteristic is analyzed and the conclusions are verified by time-domain ***,the penalty functions of the oscillation modes and decay modes are taken as the objective function,and an optimization strategy based on the Monte Carlo method is proposed to solve the parameter optimization *** simulation results are presented to validate the effectiveness of the proposed strategy.

关键词： Wind-thermal-bundled power transmission line-commutated converter based high-voltage direct current(LCC-HVDC) path analysis method(PAM) damping characteristic analysis Monte Carlo method