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The Conjugacy of Long Periodic Auroral Luminosity Pulsations

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The Conjugacy of Long Periodic Auroral Luminosity Pulsations

Bidirectional high sidelobe suppression silicon optical phased array

1997年中国地球物理学会第十三届学术年会

作者： T．Araki N．Sato T．Kamei T．Iyemori A．Kadokura H．Minatoya Faculty of Science Kyoto Univ National Institute of Polar Research Faculty of Science Kyoto Univ Faculty of Science Kyoto Univ National Institute of Polar Research University of electro-Communications

＜正＞Auroral luminosity pulsation so far observed on the ground may be divided mainly into two *** first occurs in common sense within pulsating patches with period of 2- 20sec,of which the characteristics were well ...

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Photonics Research 2023年第4期11卷 659-668页

作者： HUAQING QIU YONG LIU XIANSONG MENG XIAOWEI GUAN YUNHONG DING HAO HU DTU electro Department of Electrical and Photonics EngineeringTechnical University of DenmarkDK-2800 Kgs.LyngbyDenmark Jiaxing Key Laboratory of Photonic Sensing&Intelligent Imaging Jiaxing 314000China Intelligent Optics&Photonics Research Center Jiaxing Research Institute Zhejiang UniversityJiaxing 314000China

An optical phased array(OPA),the most promising non-mechanical beam steering technique,has great potential for solid-state light detection and ranging systems,holographic imaging,and free-space optical communications.A high quality beam with low sidelobes is crucial for long-distance free-space transmission and ***,most previously reported OPAs suffer from high sidelobe levels,and few efforts are devoted to reducing sidelobe levels in both azimuthal(φ)and polar(θ)*** solve this issue,we propose a Y-splitter-assisted cascaded coupling scheme to realize Gaussian power distribution in the azimuthal direction,which overcomes the bottleneck in the conventional cascaded coupling scheme and significantly increases the sidelobe suppression ratio(SLSR)in theφdirection from 20 to 66 dB in theory for a 120-channel ***,we designed an apodized grating emitter to realize Gaussian power distribution in the polar direction to increase the *** on both designs,we experimentally demonstrated a 120-channel OPA with dual-Gaussian power distribution in bothφandθ*** SLSRs inφandθdirections are measured to be 15.1 d B and 25 dB,***,we steer the beam to the maximum field of view of 25°×13.2°with a periodic 2λpitch(3.1μm).The maximum total power consumption is only 0.332 W with a thermo-optic efficiency of 2.7 m W∕π.

关键词： sidelobe optical directions

An integrated analysis platform merging SuperDARN data within the THEMIS tool developed by ERG-Science Center (ERG-SC)

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Advances in polar Science 2013年第1期24卷 69-77页

作者： Tomoaki Hori Nozomu Nishitani Yoshizumi Miyoshi Yukinaga Miyashita Kanako Seki Tomonori Segawa Keisuke Hosokawa Akira S Yukimatu Yoshimasa Tanaka Natsuo Sato Manabu Kunitake Tsutomu Nagatsuma Solar-Terrestrial Environment Laboratory Nagoya University Furou-cho The University of electro-Communications National Institute of polar Research National Institute of Information and Communications Technology

The Energization and Radiation in Geospace （ERG） mission seeks to explore the dynamics of the radiation belts in the Earth＇s inner magnetosphere with a space-borne probe （ERG satellite） in coordination with related ground observations and simulations/modeling studies. For this mission, the Science Center of the ERG project （ERG-SC） will provide a useful data analysis platform based on the THEMIS Data Analysis software Suite （TDAS）, which has been widely used by researchers in many conjunction studies of the Time History of Events and Macroscale Interactions during Substorms （THEMIS） spacecraft and ground data. To import SuperDARN data to this highly useful platform, ERG-SC, in close collaboration with SuperDARN groups, developed the Common Data Format （CDF） design suitable for fitacf data and has prepared an open database of SuperDARN data archived in CDE ERG-SC has also been developing programs written in Interactive Data Language （IDL） to load fltacf CDF files and to generate various kinds of plots-not only range-time-intensity-type plots but also two-dimensional map plots that can be superposed with other data, such as all-sky images of THEMIS-GBO and orbital footprints of various satellites. The CDF-TDAS scheme developed by ERG-SC will make it easier for researchers who are not familiar with SuperDARN data to access and analyze SuperDARN data and thereby facilitate collaborative studies with satellite data, such as the inner magnetosphere data pro- vided by the ERG （Japan）-RBSP （USA）-THEMIS （USA） fleet.

关键词： ERG Science Center SuperDARN database data analysis software TItEMIS Common Data Format

NaNbO_(3) modulated phase transition behavior and antiferroelectric stability evolution in 0.88(Bi_(0.5)Na_(0.5))TiO_(3)-0.12BaTiO_(3) lead-free ceramics

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Journal of Materiomics 2022年第5期8卷 1067-1076页

作者： Yi Zhang Jian Fu Aiwen Xie Tianyu Li Xuewen Jiang Ruzhong Zuo Dou Zhang Institute of electro Ceramics&Devices School of Materials Science and EngineeringHefei University of TechnologyHefei230009China Center for Advanced Ceramics School of Materials Science and EngineeringAnhui Polytechnic UniversityWuhu241000China State Key Laboratory of Power Metallurgy Central South UniversityChangshaHunan410083China

Giant strains in(Bi_(0.5)Na_(0.5))TiO_(3) based ceramics are usually attributed to electric field induced nonpolar to polar phase *** it is an ergodic relaxor R3c/P4mm ferroelectric(FE)to long-range ordered FE phase transformation or a reversible P4bm antiferroelectric(AFE)to FE phase transition is still ***,lead-free(0.88-x)(Bi_(0.5)Na_(0.5))TiO_(3)-0.12BaTiO_(3-x)NaNbO_(3) ceramics exhibit a compositionmodulated FE tetragonal P4mm to relaxor AFE tetragonal P4bm phase transition,in which double hysteresis loop,sprout-shaped S-E curves,near-zero quasi-static d33 together with a large volume change suggest the AFE characteristics of P4bm *** interesting finding is that the reversibility of fieldinduced AFE P4bm phase to FE P4mm phase transition strongly depends on the NN content,from being completely irreversible at x=0.01e0.02,to partially reversible at x=0.03e0.05,and finally to completely reversible at x=*** is indicated that the variation of reversibility should be attributed to the change of relative free energy caused by decreasing the FE to AFE phase transition temperature with increasing the NN content.

关键词： Lead-free ceramic Sodium bismuth titanate Strains Antiferroelectric stability

Imaging energetic electron spectrometer onboard a Chinese navigation satellite in the inclined GEO orbit

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Science China(Technological Sciences) 2018年第12期61卷 1845-1865页

作者： ZOU Hong YE YuGuang ZONG QiuGang CHEN HongFei ZOU JiQing CHEN Jiang SHI WeiHong YU XiangQian ZHONG WeiYing WANG YongFu ZHOU XuZhi HAO YiXin CHEN XingRan JIA XiangHong XU Feng SHAO SiPei WANG Bo HAO Xiaoyun ZHANG XiaoXin Institute of Space Physics and Applied Technology Peking University Beijing 100871 China State Key Laboratory of Space Medicine Fundamentals and Application Chinese Astronaut Research and Training Center Beijing 100094 China Shandong Aerospace electro-technology Yantai 264000 China Key Laboratory of Space Weather National Center for Space Weather Beijing 100081 China

The energetic electron measurement is one of the most important issues to understand dynamics in space physics and the applications for space weather. In this study, the principle and functional components of the imaging energetic electron spectrometer(IES) onboard a Chinese navigation satellite in the inclined GEO orbit(IGSO) was introduced. The IES instrument is developed by the team in Peking University(BeiDa), thus it is named as BD-IES. Based on the pin-hole technique, the instrument can measure 50–600 keV electrons incident from 9 directions over a range of 180° in polar angle. With pulse height analysis(PHA), the spectrum can be determined for each direction. The energy and angular calibrations were performed, which show the good energy and angular characteristics of BD-IES. Monte Carlo simulations show that the anti-proton design of BDIES can effectively decrease the proton contamination on the electron measurements in the inclined GEO orbit. The primary results of BD-IES verify the successful design of this instrument.

关键词： imaging energetic electron spectrometer pin-hole imaging system IGSO satellite

Highly stable full-color display device with VLC application potential using semipolarμLEDs and all-inorganic encapsulated perovskite nanocrystal

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Photonics Research 2021年第11期9卷 2132-2143页

作者： TINGZHU WU YUE LIN YU-MING HUANG MENG LIU KONTHOUJAM JAMES SINGH WANSHENG LIN TINGWEI LU XI ZHENG JIANYANG ZHOU HAO-CHUNG KUO ZHONG CHEN School of electronic Science and Engineering Fujian Engineering Research Center for Solid-State LightingXiamen UniversityXiamen 361005China Fujian Science&Technology Innovation Laboratory for Energy Materials of China Xiamen 361005China Department of Photonics and Graduate Institute of electro-Optical Engineering College of Electrical and Computer EngineeringTaiwan Chiao Tung UniversityHsinchu 30010China Semiconductor Research Center Hon Hai Research InstituteTaipei 11492China

A promising approach for the development of effective full-color displays is to combine blue micro LEDs(μLEDs)with color conversion *** nanocrystals(PNCs)are notable for their tolerance to defects and provide excellent photoluminescence quantum yields and high color purity compared to metal chalcogenide quantum *** stability of PNCs in ambient conditions and under exposure to blue light can be improved using a SiO;*** study proposes a device that could be used for both display and visible light communication(VLC)*** semipolar blueμLED array fabricated in this study shows a negligible wavelength shift,indicating a significant reduction in the quantum confined Stark *** to its shorter carrier lifetime,the semipolar μLED array exhibits an impressive peak 3 dB bandwidth of 655 MHz and a data transmission rate of1.2 Gb/s corresponding to an injection current of 200 m *** PNC-μLED device assembled from a semipolarμLED array with PNCs demonstrates high color stability and wide color-gamut features,achieving 127.23% and 95.00%of the National Television Standards Committee standard and Rec.2020 on the CIE 1931 color diagram,*** results suggest that the proposed PNC-μLED device is suitable for both display-related and VLC applications.

关键词： VLC quantum polar

A Review on Extraction of Lakes from Remotely Sensed Optical Satellite Data with a Special Focus on Cryospheric Lakes

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Advances in Remote Sensing 2015年第3期4卷 196-213页

作者： Shridhar D. Jawak Kamana Kulkarni Alvarinho J. Luis polar Remote Sensing Division Earth System Science Organization (ESSO) National Centre for Antarctic & Ocean Research (NCAOR) Ministry of Earth Sciences Vasco da Gama India School of electronics Devi Ahilya Vishwavidyalaya Indore India

Water on the Earth’s surface is an essential part of the hydrological cycle. Water resources include surface waters, groundwater, lakes, inland waters, rivers, coastal waters, and aquifers. Monitoring lake dynamics is critical to favor sustainable management of water resources on Earth. In cryosphere, lake ice cover is a robust indicator of local climate variability and change. Therefore, it is necessary to review recent methods, technologies, and satellite sensors employed for the extraction of lakes from satellite imagery. The present review focuses on the comprehensive evaluation of existing methods for extraction of lake or water body features from remotely sensed optical data. We summarize pixel-based, object-based, hybrid, spectral index based, target and spectral matching methods employed in extracting lake features in urban and cryospheric environments. To our knowledge, almost all of the published research studies on the extraction of surface lakes in cryospheric environments have essentially used satellite remote sensing data and geospatial methods. Satellite sensors of varying spatial, temporal and spectral resolutions have been used to extract and analyze the information regarding surface water. Multispectral remote sensing has been widely utilized in cryospheric studies and has employed a variety of electro-optical satellite sensor systems for characterization and extraction of various cryospheric features, such as glaciers, sea ice, lakes and rivers, the extent of snow and ice, and icebergs. It is apparent that the most common methods for extracting water bodies use single band-based threshold methods, spectral index ratio (SIR)-based multiband methods, image segmentation methods, spectral-matching methods, and target detection methods (unsupervised, supervised and hybrid). A Synergetic fusion of various remote sensing methods is also proposed to improve water information extraction accuracies. The methods developed so far are not generic rather they a

关键词： Cryospehere Remote Sensing Semi-Automatic Extraction Lakes Spectral Index Ratio

Ultrahigh energy density and improved discharged efficiency in bismuth sodium titanate based relaxor ferroelectrics with A-site vacancy

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Journal of Materiomics 2018年第3期4卷 202-207页

作者： Xiao Liu Jing Shi Fangyuan Zhu Huiling Du Tangyuan Li Xiangchun Liu Hai Lu School of Materials Science and Engineering Xi'an University of Science and TechnologyXi'an710054China School of electro-Mechanical Engineering Xidian UniversityXi'an710071China Shanghai Synchrotron Radiation Facility Shanghai Institute of Applied PhysicsChinese Academy of SciencesShanghai 201204China Frontier Institute of Science and Technology Xi'an Jiaotong UniversityXi'an710049China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an710072China

Novel A-site deficient(1-x-y)Bi_(0.5)Na_(0.5)TiO_(3-x)BaTiO_(3-y)Bi_(0.2)Sr_(0.7)TiO_(3)lead-free relaxor ferroelectrics have been explored for energy storage *** slim polarization hysteresis(P-E)loops are observed in 0.655Bi_(0.5)Na_(0.5)TiO_(3)-0.065BaTiO_(3)-0.28Bi_(0.2)Sr_(0.7)□_(0.1)TiO_(3)(6.5BNBT-BST)at ambient temperature resulting in a giant recoverable energy density(W_(rec)=1.5 J cm^(-3))and extremely high efficiency(η=90%)at 100 kV cm^(-1),which are closed related to the track of P-E *** the addition of Bi_(0.2)Sr_(0.7)TiO_(3)(BST)content,the ergodic relaxor phase becomes dominant with dynamic polar nanoregions attributed to the absence of ferroelectric domain in the relaxor ***,the recoverable energy density exhibits small variation in elevated temperature where the depressed polarization is compensated by almost hysteresis free loops(ηup to 97%).The achievement of these characteristics in P-E loops provides that Bi_(0.2)Sr_(0.7)TiO_(3)tailoring by A-site vacancies is a potential route when designing new relaxor ferroelectrics for energy-storage applications.

关键词： Lead-free ceramics Bi_(0.5)Na_(0.5)TiO_(3) Energy storage Efficiency A-site vacancy

Energy‑efcient integrated silicon optical phased array

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Frontiers of Optoelectronics 2023年第3期16卷 77-100页

作者： Huaqing Qiu Yong Liu Xiansong Meng Xiaowei Guan Yunhong Ding Hao Hu DTU electro Department of Electrical and Photonics EngineeringTechnical University of DenmarkKgs.Lyngby DK-2800Denmark Interuniversity Microelectronics Center(IMEC) Kapeldreef 75Leuven 3001Belgium Jiaxing Key Laboratory of Photonic Sensing and Intelligent Imaging Jiaxing 314000China Intelligent Optics and Photonics Research Center Jiaxing Research InstituteZhejiang UniversityJiaxing 314000China

An optical phased array(OPA)is a promising non-mechanical technique for beam steering in solid-state light detection and ranging *** performance of the OPA largely depends on the phase shifter,which afects power consumption,insertion loss,modulation speed,and ***,for a thermo-optic phase shifter,achieving good performance in all aspects is challenging due to trade-ofs among these *** this work,we propose and demonstrate two types of energy-efcient optical phase shifters that overcome these trade-ofs and achieve a well-balanced performance in all ***,the proposed round-spiral phase shifter is robust in fabrication and fully compatible with deep ultraviolet(DUV)processes,making it an ideal building block for large-scale photonic integrated circuits(PICs).Using the high-performance phase shifter,we propose a periodic OPA with low power consumption,whose maximum electric power consumption within the feld of view is only 0.33 ***,we designed Gaussian power distribution in both the azimuthal(ψ)and polar(θ)directions and experimentally achieved a large sidelobe suppression ratio of 15.1 and 25 dB,respectively.

关键词： Optical phased array Optical phase shifter Silicon photonics Integrated optics