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Self-design of arbitrary polarization-control waveplates via deep neural networks

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Photonics Research 2023年第5期11卷 695-711页

作者： ZHENGCHANG liU ZHIBO DANG ZHIXIN liU YU li XIAO HE YUCHEN DAI YUXIANG CHEN PU PENG zheyu FANG School of Physics State Key Lab for Mesoscopic PhysicsAcademy for Advanced Interdisciplinary StudiesCollaborative Innovation Center of Quantum MatterYangtze Delta Institute of Optoelectronicsand Nano-optoelectronics Frontier Center of Ministry of EducationPeking UniversityBeijing 100871China

The manipulation of polarization states beyond the optical limit presents advantages in various *** progress has been made in the design of meta-waveplates for on-demand polarization transformation,realized by numerical simulations and parameter sweep ***,due to the limited freedom in these classical strategies,particular challenges arise from the emerging requirement for multiplex optical devices and multidimensional manipulation of light,which urge for a large number of different nanostructures with great polarization control ***,we demonstrate a set of self-designed arbitrary wave plates with a high polarization conversion *** combine Bayesian optimization and deep neural networks to design perfect halfand quarter-waveplates based on metallic nanostructures,which experimentally demonstrate excellent polarization control functionalities with the conversion ratios of 85%and 90%.More broadly,we develop a comprehensive wave plate database consisting of various metallic nanostructures with high polarization conversion efficiency,accompanying a flexible tuning of phase shifts(0-2π)and group delays(0-10 fs),and construct an achromatic metalens based on this *** to the versatility and excellent performance,our self-designed wave plates can promote the performance of multiplexed broadband metasurfaces and find potential applications in compact optical devices and polarization division multiplexing optical communications.

关键词： polarization tuning wave

Rotor performance enhancement by alternating current dielectric barrier discharge plasma actuation

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Plasma Science and Technology 2023年第1期25卷 120-127页

作者：赵光银王畅杨永东李国强史喆羽 China Aerodynamics Research and Development Center Low Speed Aerodynamics InstituteMianyang 621000People's Republic of China

An experimental system was established to explore the plasma flow control effect for helicopter rotors in hover *** the plasma actuator applied at the leading edge of the rotor blades,alternating current dielectric barrier discharge(AC-DBD) plasma actuation was generated by a sinusoidal AC high-voltage *** direct force measurement,the influence of actuation parameters on the aerodynamic performance of the rotor was investigated at a tip Reynolds number of 1.7 × ***-DBD actuation can delay the blade stall to more than 3° with a 20%increase of about in the thrust coefficient at the post-stall *** a constant motor power driving the rotor,AC-DBD actuation could reduce the rotor’s torque at the stalled pitch and increase the rotational speed of the ***,AC-DBD actuation could maintain a relatively high hover efficiency of the rotor at large collective *** a wide range of actuation parameters,AC-DBD plasma actuation could improve the rotor’s aerodynamic performance at large blade ***-speed photography of the tuft motion on the blade’s upper surface showed that AC-DBD plasma actuation could promote the reattachment of the blade’s separation flow.

关键词： rotor flow control plasma actuator dielectric barrier discharge force measurement

Morphing UAV Formation Control Based on Adaptive Dynamic Programming

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Morphing UAV Formation Control Based on Adaptive Dynamic Pro...

Performance Assessment of Real-Time Precise Point Positioning Using SSR Corrections

第43届中国控制会议

作者： Ruifeng li liqian Dou Hui Yu zheyu Zhang Hao Cheng School of Electrical Engineering and Automation Tianjin University

In this study,an adaptive dynamic programming-based collaborative tracking control algorithm is developed for the formation of morphing unmanned aerial vehicles(UAVs).The multi-morphing UAVs system is divided into the position and attitude *** the position subsystem,a novel cost function fused with the impact of UAV morphing is introduced and the position controllers for morphing UAVs are developed using adaptive dynamic programming(ADP).To quantify the impact of morphing,a high-order finite-time observer is introduced which estimates the acceleration from aerodynamic force acting on the *** the attitude subsystem,an integral back-stepping controller is *** stability of morphing UAV formation is theoretically proven with the Lyapunov *** involving comparisons with PID algorithm and sliding mode control(SMC) method have been conducted to validate its effectiveness and robustness.

关键词： Morphing Unmanned Aerial Vehicle Formation Control Adaptive Dynamic Programming Optimal Control

来源： cnki会议评论

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Performance Assessment of Real-Time Precise Point Positionin...

Simulation of pore space production law and capacity expansion mechanism of underground gas storage

第十一届中国卫星导航年会

作者： Ruijin Qiu zheyu Feng Chenzhong Gu Zhimin Yuan Jianwen li Information Engineering University Central South University

Centre National d’Etudes Spatiales(CNES) now provides real-time correction information such as orbits/clock correction,code/phase bias,and ionospheric spherical harmonic coefficients,which are so-call

关键词： real-time precise point positioning CNES SSR corrections performance assessment CLK93

来源： cnki会议 cnki会议 cnki会议评论

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Petroleum Exploration and Development 2022年第6期49卷 1423-1429页

作者： liU Tao li Yiqiang DING Guosheng WANG Zhengmao SHI Lei liU zheyu TANG Xiang CAO Han CAO Jinxin HUANG Youqing State Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing 102249China Petroleum Engineering Institute China University of Petroleum(Beijing)Beijing 102249China PetroChina Research Institute of Petroleum Exploration&Development Beijing 100083China CNPC Key Laboratory of Oil&Gas Underground Storage Engineering Beijing 100083China PetroChina Exploration&Production Company Beijing 100120China

One-dimensional gas injection storage building and one-cycle injection-production modeling experiment,and two-dimensional flat core storage building and multi-cycle injection-production modeling experiment were carried out using one-dimensional long core and large two-dimensional flat physical models to find out the effects of reservoir physical properties and injection-production balance time on reservoir pore utilization efficiency,effective reservoir capacity formation and capacity-reaching *** results show that reservoir physical properties and formation water saturation are the main factors affecting the construction and operation of gas-reservoir type underground gas *** the construction and operation of gas-reservoir type gas storage,the reservoir space can be divided into three types of working zones:high efficiency,low efficiency and ineffective *** higher the reservoir permeability,the higher the pore utilization efficiency is,the smaller the ineffective working zone is,or there is no ineffective working zone;the smaller the loss of injected gas is,and the higher the utilization rate of pores *** better the reservoir physical properties,the larger the reservoir space and the larger the final gas storage capacity *** higher the water saturation of the reservoir,the more the gas loss during gas storage capacity building and operation *** injection-production regime to discharge water and reduce water saturation is an effective way to reduce gas loss in gas *** the process of multiple cycles of injection and production,there is a reasonable injection-production balance time,further extending the injection-production balance period after reaching the reasonable time has little contribution to the expansion of gas storage capacity.

关键词： gas reservoir-type underground gas storage multi-cycle injection and production injection-production equilibrium time pore utilization efficiency effective gas storage volume

风险偏好、政策干预与实地养分管理技术采纳——基于世行贷款农业面源污染治理项目的考察

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农林经济管理学报 2022年第1期21卷 10-19页

作者：左喆瑜李周新疆大学经济与管理学院新疆乌鲁木齐830000 仲恺农业工程学院经贸学院广东广州510225 中国社会科学院农村发展研究所北京100732

根据世行贷款农业面源污染治理项目村和非项目村1 190个地块数据,基于行为经济学的前景理论在测度农户风险偏好参数的基础上,利用bivariate probit模型探讨政策干预是否有助于缓解风险厌恶程度对农户实地养分管理技术采纳行为的抑制作用... 详细信息

根据世行贷款农业面源污染治理项目村和非项目村1 190个地块数据,基于行为经济学的前景理论在测度农户风险偏好参数的基础上,利用bivariate probit模型探讨政策干预是否有助于缓解风险厌恶程度对农户实地养分管理技术采纳行为的抑制作用,并借助两阶段方法分析风险偏好和政策干预对肥料生产率和肥料投入环境效率的影响。结果表明:风险厌恶系数和对小概率事件重视系数对农户实地养分管理技术采纳行为具有消极影响,技术支持政策对实地养分管理技术采纳行为影响为正;绿色农业补贴政策能够缓解风险厌恶程度对农户实地养分管理技术采纳行为的抑制作用;对于完全采纳行为,绿色农业补贴政策和技术支持政策会产生正的环境效应。基于此,建议通过绿色农业补贴政策调节风险偏好对农户实地技术采纳行为的消极影响,实施精准培训和促进社会学习提高技术采纳水平。

关键词：农业绿色发展风险偏好绿色农业补贴政策前景理论行为经济学

最低工资与买方垄断劳动市场的持续存在——江浙沪最低工资线的就业效果比较

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审计与经济研究 2017年第6期32卷 90-101页

作者：李晓春董哲昱南京大学商学院江苏南京210093

分析发展中国家在经济发展过程中,面对劳动力市场存在的持续性买方垄断行为,通过提升最低工资来持续性促进就业的特征,并以江浙沪的数据进行实证分析。研究发现:江浙沪的劳动力市场存在持续性买方垄断,但三地最低工资的就业效果不同;上... 详细信息

分析发展中国家在经济发展过程中,面对劳动力市场存在的持续性买方垄断行为,通过提升最低工资来持续性促进就业的特征,并以江浙沪的数据进行实证分析。研究发现:江浙沪的劳动力市场存在持续性买方垄断,但三地最低工资的就业效果不同;上海和浙江最低工资相对于城镇劳动者人均可支配收入偏低,最低工资上升对就业有促进作用,而江苏最低工资相对于城镇劳动者人均可支配收入偏高,最低工资上升对就业有抑制作用;上海和浙江相比,上海最低工资提升所能带动的就业量大于浙江;最低工资上升主要影响小型企业和民营企业。

关键词：最低工资持续买方垄断劳动市场江浙沪三地就业就业政策人口流动农民工城镇化农民工就业劳动力需求弹性

Bi-channel near-and far-field optical vortex generator based on a single plasmonic metasurface

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Photonics Research 2020年第6期8卷 986-994页

作者： QIAO JIANG YANJUN BAO JING li liFENG TIAN ToNG CUI liN SUN BOWEN DU BOWEN li BENFENG BAI JIA WANG HONGBO SUN Bo SHEN HAN ZHANG FENG liN XING ZHU zheyu FANG School of Physics State Key Laboratory for Mesoscopic PhysicsAcademy for Advanced Interdisciplinary Studiesand Nano-optoelectronics Frontier Center of Ministry of EducationPeking UniversityBeiing 100871China Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technica/Institute of Physics and ChemistryChinese Academy of SciencesBeiing 100190China State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentsTsinghua UniversityBeijing 100084China Collaborative Innovation Center of Quantum Matter BejingChina

With the recent development of the metasurface,generating an optical vortex in optical far or near fields is realized in various ***,to generate vortices in both the near and far fields simultaneously is still a challenge,although it has great potential in the future compact and versatile photonic ***,a bi-channel optical vortex generator in both the near and far fields is proposed and demonstrated within a single metasurface,where the surface plasmon vortex and the far-field optical vortex can be simultancously generated under circularly polarized *** ability of generating vortices with arbitrary topological charges is experimentally demon-strated,which agrces well with *** approach provides great freedom to integrate different vortex generators in a single device and ofers new opprtunities for integrated optical communications,trapping,and other related fields.

关键词： vortex generator generating

Rapid colorimetric detection of Cr3+ and Cr2O72- based on green synthesized of gold nanoparticles

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Rapid colorimetric detection of Cr3+ and Cr2O72- based on gr...