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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

大规模新能源接入的电力系统惯量缺失机理及惯量水平评估

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南方能源建设 2024年第5期11卷 132-139页

作者：李逸欣吴伟杰张伊宁郑敏嘉娄源媛庾力维蔡颖倩广东电网有限责任公司电网规划研究中心广东广州510000 广东电网有限责任公司广东广州510000 广东电网有限责任公司东莞供电局广东东莞523000 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

[目的]为满足我国“30、60”的碳达峰、碳中和目标,大量风电、光伏等新能源发电通过变流器接口接入系统,以替代燃煤同步机组出力,极大地影响了电力系统惯量及相应的频率动态特性。[方法]首先分析传统电力系统惯量运动方程及传统发电机... 详细信息

[目的]为满足我国“30、60”的碳达峰、碳中和目标,大量风电、光伏等新能源发电通过变流器接口接入系统,以替代燃煤同步机组出力,极大地影响了电力系统惯量及相应的频率动态特性。[方法]首先分析传统电力系统惯量运动方程及传统发电机扰动后的惯量响应阶段的功频动态过程,再定性讨论了大规模新能源接入后的系统惯性缺失机理。[结果]讨论了国内外常用的集中惯性评价指标,阐述了用系统的总动能和惯性常数作为电网惯性评价指标的依据。[结论]结合某省级电网的新能源开发和消纳的规划,对该省级电网的惯量水平进行了工程化评估,提出了相应的惯量提升建议。

关键词：新能源发电电力系统惯量频率惯量常数

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

Thin-film neural networks for optical inverse problem

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Light(Advanced Manufacturing) 2021年第4期2卷 23-30页

作者： Lingjie Fan Ang Chen Tongyu Li Jiao Chu Yang Tang Jiajun Wang Maoxiong Zhao Tangyao Shen minjia zheng Fang Guan Haiwei Yin 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 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 Microsstructures Nanjing UniversityNanjing 210093China

The thin-film optical inverse problem has attracted a great deal of attention in science and industry,and is widely applied to optical ***,as the number of layers increases,the time it takes to extract the parameters of thin films drastically ***,we introduce the idea of exploiting the structural similarity of all-optical neural networks and applied it to the optical inverse *** propose thin-film neural networks(TFNNs)to efficiently adjust all the parameters of multilayer thin *** test the performance of TFNNs,we implemented a TFNN algorithm,and a reflectometer at normal incidence was *** on multilayer thin films with 232 layers,it is shown that TFNNs can reduce the time consumed by parameter extraction,which barely increased with the number of layers compared with the conventional *** were also used to design multilayer thin films to mimic the optical response of three types of cone cells in the human *** light passing through these multilayer thin films was then recorded as a colored photo.

关键词： method inverse film

Photonic-dispersion neural networks for inverse scattering problems

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Light(Science & Applications) 2021年第10期10卷 1819-1828页

作者： Tongyu Li Ang Chen Lingjie Fan minjia zheng Jiajun Wang Guopeng Lu Maoxiong Zhao Xinbin Cheng Wei Li Xiaohan Liu Haiwei Yin Lei Shi Jian Zi State Key Laboratory of Surface Physics Key Laboratory of Micro-and NanoPhotonics Structures(Ministry of Education)and Department of PhysicsFudan UniversityShanghai 200433China Shanghai Engineering Research Center of Optical Metrology for Nano-fabrication(SERCOM) Shanghai 200433China Institute of Precision Optical Engineering School of Physics Science and EngineeringTongji UniversityShanghai 200092China National Institute of Metrology Beijing 100029China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China

Inferring the properties of a scattering objective by analyzing the optical far-field responses within the framework of inverse problems is of great practical ***,it still faces major challenges when the parameter range is growing and involves inevitable experimental ***,we propose a solving strategy containing robust neuralnetworks-based algorithms and informative photonic dispersions to overcome such challenges for a sort of inverse scattering problem—reconstructing grating *** two typical neural networks,forward-mapping type and inverse-mapping type,we reconstruct grating profiles whose geometric features span hundreds of nanometers with nanometric sensitivity and several seconds of time consumption.A forward-mapping neural network with a parameters-to-point architecture especially stands out in generating analytical photonic dispersions accurately,featured by sharp Fano-shaped ***,to implement the strategy experimentally,a Fourier-optics-based angle-resolved imaging spectroscopy with an all-fixed light path is developed to measure the dispersions by a single shot,acquiring adequate *** forward-mapping algorithm can enable real-time comparisons between robust predictions and experimental data with actual noises,showing an excellent linear correlation(R2>0.982)with the measurements of atomic force *** work provides a new strategy for reconstructing grating profiles in inverse scattering problems.

关键词： scattering dispersion neural

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