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First wetland mapping at 10-m spatial resolution in South America using multi-source and multi-feature remote sensing data

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science China Earth sciences 2024年第10期67卷 3252-3269页

作者： Weiwei SUN Gang YANG Yuling HUANG Dehua MAO Ke HUANG Lin ZHU Xiangchao MENG Tian FENG Chao CHEN Yong GE Department of Geography and spatial information Techniques Ningbo University State Key Laboratory of Resources and Environmental information System Institute of Geographic Sciences & Natural Resources ResearchChinese Academy of Sciences Natural Resources and Planning Bureau Shanghai Pudong New District Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Faculty of Electrical Engineering and Computer science Ningbo University School of Geography science and Geomatics Engineering Suzhou University of Science and Technology

Wetland degradation has been accelerating in recent years globally. Accurate information on the geographic distribution and categories of wetlands is essential for their conservation and management. Despite being the world′s fourth largest continent, South America has limited research on wetland mapping, and there is currently no available map that provides comprehensive information on wetland distribution and categories in the region. To address this issue, we used Sentinel-1, Sentinel-2 and SRTM data, developed a sample collection method and a wetland mapping method with a collection of multi-source features such as optical features, polarization features and shape features for South American wetlands. We produced a 10-m resolution wetland map based on the Google Earth Engine（GEE） platform. Our Level-1 wetland cover map accurately captured six wetland sub-categories with an overall accuracy of 96.24% and a kappa coefficient of 0.8649, while our Level-2 water cover map included five sub-categories with an overall accuracy of 97.23% and a kappa coefficient of0.9368. The results show that the total area of existing wetlands in South America is approximately 1,737,000 km2, which is6.8% of the total land area. Among the ten wetland categories, shallow sea had the largest area（960,527.4 km2）, while aquaculture ponds had the smallest area 1513.6 km2. Swamp had the second largest area（306,240.1 km2）. Brazil, Argentina,Venezuela, Bolivia, and Colombia were found to have the largest wetland areas, with Brazil and Colombia having the most diverse wetland categories. This product can serve as baseline data for subsequent monitoring, management, and conservation of South American wetlands.

关键词： Wetland mapping Google Earth Engine Sentinel imagery South America

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A Tutorial on Quantized Feedback Control

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IEEE/CAA Journal of Automatica Sinica 2024年第1期11卷 5-17页

作者： Minyue Fu IEEE the School of System Design and Intelligent Manufacturing Shenzhen Key Laboratory of Control Theory and Intelligent Systems and Centre for Control Science and TechnologySouthern University of Science and TechnologyShenzhen 518055China

In this tutorial paper, we explore the field of quantized feedback control, which has gained significant attention due to the growing prevalence of networked control systems. These systems require the transmission of feedback information, such as measurements and control signals, over digital networks, presenting novel challenges in estimation and control design. Our examination encompasses various topics, including the minimal information needed for effective feedback control, the design of quantizers, strategies for quantized control design and estimation,achieving consensus control with quantized data, and the pursuit of high-precision tracking using quantized measurements.

关键词： Consensus control high-precision control networked control quantized estimation quantized feedback control robust control

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Prediction of Sea Ice Concentration Anomalies in The Barents-Kara Sea Based on Machine Learning

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Journal of Earth science 2024年

作者： Luzhen Wu Ming Shangguan Jintao Zhu Qimin Deng Shuyun Zhao Wuke Wang School of Geography and information Engineering， China University of Geosciences Department of Atmospheric science， China University of Geosciences(Wuhan) centre for Severe Weather and Climate and Hydro-Geological Hazards Research centre for Complex Air Pollution of Hubei Province

. Variations of sea ice in the Barents-Kara seas attracts global attention because of its both local and remote climate impacts. The accurate prediction of Barents-Kara Seas sea ice concentration anomalies (BKSICA) is critically important for science and economics. This study employs four machine learning (ML) models， including extreme learning machine (ELM)， nonlinear autoregressive exogenous model (NARX)， long short-term memory (LSTM)， and extreme gradient boosting (XGBoost)， combined with empirical orthogonal function (EOF) methods to predict seasonal BKSICA. The ML models are trained based on the 1979-2014 oceanic and meteorological data， and are then used to predict the BKSICA for 2015-2022. Results indicate that the ML models provide reliable prediction up to 6 months， achieving a PCC over 0.6. Such prediction skill outperforms the state-of-the-art dynamical model at 2-6 months’ prediction， although it is slightly less accurate at 1 month lead time. Among them， the ELM exhibits the optimal performance， attaining a regional average Pearson correlation coefficient (PCC) of 0.18 higher than the ECMWF at a 6-month lead time. The physical interpretability of the ML models is also analyzed， showing that subsurface ocean heat content anomalies to be a critical new predictor for BKSICA. These results highlight the effectiveness of the ML models in seasonal sea ice prediction.

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UltrahighQ Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)microwave dielectric ceramics for temperature-stable millimeter-wave dielectric resonator antennas

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Journal of Advanced Ceramics 2024年第2期13卷 155-165页

作者： Guoqiang He Yu Jiang Kaixin Song Yanjun Liu Yuan Nie Wenjie Zhang Ziqi Zhao Yinghan He Xinyue Ma Xiuli Chen Xu Li Huanfu Zhou Collaborative Innovation centre for Exploration of Hidden Nonferrous Metal Deposits and Development of New Materials in Guangxi Key Laboratory of Nonferrous Materials and New Processing TechnologyMinistry of EducationSchool of Materials Science and EngineeringGuilin University of TechnologyGuilin 541004China College of Electronic information Hangzhou Dianzi UniversityHangzhou 310018China

Microwave dielectric ceramics should be improved to advance mobile communication technologies *** this study,we prepared Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics with nonstoichiometric Sr^(2+)ratios based on our previously reported SrY_(2)O_(4) microwave dielectric ceramic,which has a low dielectric constant and an ultrahigh quality factor(Q value).The ceramic exhibited a 33.6% higher Q-by-frequency(Q×f)value(Q≈12,500)at x=0.02 than SrY_(2)O_(4).All Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics exhibited pure phase structures,although variations in crystal-plane spacings were *** ceramics are mainly composed of Sr-O,Y1-O,and Y_(2)-O octahedra,with the temperature coefficient of the resonant frequency(τ_(f))of the ceramic increasing with Y_(2)-O octahedral *** ceramic comprises uniform grains with a homogeneous elemental distribution,clear grain boundaries,and no obvious cavities at x=*** Sr_(1+x)Y_(2)O_(4+x)(x=0-0.04)ceramics exhibited good microwave dielectric properties,with optimal performance observed at x=0.02(dielectric constant(εr)=15.41,Q×f=112,375 GHz,and τ_(f)=-17.44 ppm/℃).The τ_(f) value was reduced to meet the temperaturestability requirements of 5G/6G communication systems by adding CaTiO_(3),with Sr_(1.02)Y_(2)O_(4.02)+2wt% CaTiO_(3) exhibiting ε_(r)=16.14,Q×f=51,004 GHz,andτf=0 ppm/℃.A dielectric resonator antenna prepared using Sr_(1.02)Y_(2)O_(4.02)+2wt%CaTiO_(3) exhibited a central frequency of 26.6 GHz,with a corresponding gain and efficiency of 3.66 dBi and 83.14%,***,Sr_(1.02)Y_(2)O_(4).02-based dielectric resonator antennas are suitable for use in 5G millimeter-wave band(24.5-27.5 GHz)applications.

关键词： millimeter wave microwave dielectric ceramics dielectric resonator antenna nonstoichiometric ratio

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Superconductivity in kagome metal ThRu3Si2

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Chinese Physics B 2024年第5期33卷 50-55页

作者：刘艺厉静杨武璋卢佳依曹博雅李华旬柴万力武思祺李佰卓孙云蕾焦文鹤王操许晓峰任之曹光旱 School of Physics Zhejiang University Department of Applied Physics Zhejiang University of Technology School of science Westlake Institute for Advanced Study Westlake University Department of Physics Shandong University of Technology School of information and Electrical Engineering Zhejiang University City College Interdisciplinary Center for Quantum information and State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University Collaborative Innovation centre of Advanced Microstructures Nanjing University

We report the physical properties of ThRu3Si2featured with distorted Ru kagome lattice. The combined experiments of resistivity, magnetization and specific heat reveal bulk superconductivity with Tc= 3.8 K. The specific heat jump and calculated electron–phonon coupling indicate a moderate coupled BCS superconductor. In comparison with LaRu3Si2,the calculated electronic structure in ThRu3Si2shows an electron-doping effect with electron filling lifted from 100 meV below flat bands to 300 meV above it. This explains the lower superconducting transition temperature and weaker electron correlations observed in ThRu3Si2. Our work suggests the Tc and electronic correlations in the kagome superconductor could have an intimate connection with the flat bands.

关键词： superconductivity kagome lattice flat band

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An improved typhoon monitoring model based on precipitable water vapor and pressure

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Geodesy and Geodynamics 2024年第3期15卷 276-290页

作者： Junyu Li Haojie Li Lilong Liu Jiaqing Chen Yibin Yao Mingyun Hu Liangke Huang Fade Chen Tengxu Zhang Lv Zhou College of Geomatics and Geoinformation Guilin University of TechnologyGuilin 541006China Guangxi Key Laboratory of spatial information and Geomatics Guilin 541006China Qinzhou Institute of Surveying and Mapping for Housing and Urban-Rural Development Co. Ltd.Qinzhou 535000China School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China School of Resources and Environmental science and Engineering Hubei University of Science and TechnologyXianning 437100China

The potential of monitoring the movement of typhoons using the precipitable water vapor(PWV) has been confirmed. However, monitoring the movement of typhoon is focused on PWV, making it difficult to describe the movement of a typhoon in detail minutely and resulting in insufficient accuracy. Hence,based on PWV and meteorological data, we propose an improved typhoon monitoring mode. First, the European centre for Medium-Range Weather Forecasts Reanalysis 5-derived PWV(ERA5-PWV) and the Global Navigation Satellite System-derived PWV(GNSS-PWV) were compared with the reference radiosonde PWV(RS-PWV). Then, using the PWV and atmospheric parameters derived from ERA5, we discussed the anomalous variations of PWV, pressure(P), precipitation, and wind speed during different typhoons. Finally, we compiled a list of critical factors related to typhoon movement, PWV and P. We developed an improved multi-factor typhoon monitoring mode(IMTM) with different models(i.e.,IMTM-I and IMTM-II) in different cases with a higher density of GNSS observation or only Numerical Weather Prediction(NWP) data. The IMTM was evaluated through the reference movement speeds of HATO and Mangkhut from the China Meteorological Observatory Typhoon Network(CMOTN). The results show that the root mean square(RMS) of the IMTM-I is 1.26 km/h based on ERA5-P and ERA5-PWV,and the absolute bias values are mostly within 2 km/h. Compared with the models considering the single factor ERA5-P/ERA5-PWV, the RMS of the IMTM-I is improved by 26.3% and 38.5%, respectively. The IMTM-II model manifests a residual of only 0.35 km/h. Compared with the single-factor model based on GNSS-PWV/P, the residual of the IMTM-II model is reduced by 90.8% and 84.1%, respectively. These results propose that the typhoon movement monitoring approach combining PWV and P has evident advantages over the single-factor model and is expected to supplement traditional typhoon monitoring.

关键词： Typhoon GNSS/ERA5 PWV Pressure Monitoring Improved model

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重金属污染与生态风险评价——基于自组织地图和正矩阵分解的临澧县土壤研究

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Journal of Central South University 2024年第4期31卷 1371-1382页

作者：邹昊李武清任伯帜谢青蔡昭奇陈禄源王瑾 School of Civil Engineering Hunan University of Science and TechnologyXiangtan 411201China Institute of Geological Survey of Hunan Province Changsha 410083China School of Resource Security Hunan University of Science and TechnologyXiangtan 411201China School of Earth science and spatial information Hunan University of Science and TechnologyXiangtan 411201China College of Foreign Languages Hunan UniversityChangsha 410082China

土壤重金属污染一直是环境科学中备受关注的问题。本文对中国临澧县土壤中六种重金属(As、Cd、Cr、Cu、Zn和Pb)的污染水平、分布、来源及其对生态环境的影响进行了分析。样本浓度分析结果显示Cd的浓度均超过背景值,超标率达到100%,其余... 详细信息

土壤重金属污染一直是环境科学中备受关注的问题。本文对中国临澧县土壤中六种重金属(As、Cd、Cr、Cu、Zn和Pb)的污染水平、分布、来源及其对生态环境的影响进行了分析。样本浓度分析结果显示Cd的浓度均超过背景值,超标率达到100%,其余元素的平均浓度与背景值相近,超标率均在13.5%以下。地累计指数和富集因子指数均显示Cd是污染最严重的元素,其他元素则处于轻度污染级别以下。自组织地图(SOM)和正矩阵分解(PMF)的分析结果显示农业活动是土壤中重金属元素主要来源之一,而自然风化和工业污染也会导致土壤污染。Cd是临澧县土壤中污染最显著的元素,对生态环境造成的影响最大,达到较高风险等级。本研究为降低土壤重金属污染和生态环境风险提供了重要参考,同时也为相关部门制定有效的污染防治、生态环境保护政策提供了理论指导。

关键词：生态风险正矩阵分解重金属污染土壤自组织地图

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High-Efficiency Photo-Induced Charge Transfer for SERS Sensing in N-Doped 3D-Graphene on Si Heterojunction

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Energy & Environmental Materials 2024年第2期7卷 272-280页

作者： Guanglin Zhang Jie Sun Genwang Wei Shan Zhang Zhengyi He Huijuan Wu Bingkun Wang Siwei Yang Guqiao Ding Zhiduo Liu Zhiwen Jin Caichao Ye Gang Wang Department of Microelectronic science and Engineering School of Physical Science and Technology Ningbo University Department of Biochemistry and Molecular Biology School of Basic Medical Sciences Shenzhen University Academy for Advanced Interdisciplinary Studies & Department of Materials science and Engineering Guangdong Provincial Key Laboratory of Computational Science and Material Design Southern University of Science and Technology State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information Technology Chinese Academy of Sciences centre for Quantum Physics Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE) School of Physics Beijing Institute of Technology School of Physical science and Technology & Key Laboratory for Magnetism and Magnetic Materials of the Ministry of Education Lanzhou University

Nitrogen-doped three-dimensional graphene（N-doped 3D-graphene） is a graphene derivative with excellent adsorption capacity, large specific surface area, high porosity, and optoelectronic properties. Herein, N-doped 3Dgraphene/Si heterojunctions were grown in situ directly on silicon（Si）substrates via plasma-assisted chemical vapor deposition（PACVD）, which is promising for surface-enhanced Raman scattering（SERS） substrates candidates. Combined analyses of theoretical simulation, incorporating N atoms in 3D-graphene are beneficial to increase the electronic state density of the system and enhance the charge transfer between the substrate and the target molecules. The enhancement of the optical and electric fields benefits from the stronger light-matter interaction improved by the natural nano-resonator structure of N-doped 3D-graphene. The as-prepared SERS substrates based on N-doped 3D-graphene/Si heterojunctions achieve ultralow detection for various molecules: 10-8M for methylene blue（MB） and10-9M for crystal violet（CRV） with rhodamine（R6G） of 10-10M. In practical detected, 10-8M thiram was precisely detected in apple peel extract. The results indicate that N-doped 3D-graphene/Si heterojunctions based-SERS substrates have promising applications in low-concentration molecular detection and food safety.

关键词： charge transfer DFT simulation N-doped 3D-graphene SERS Thiram detection

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Super-resolution diffractive neural network for alloptical direction of arrival estimation beyond diffraction limits

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Light(science & Applications) 2024年第8期13卷 1602-1614页

作者： Sheng Gao Hang Chen Yichen Wang Zhengyang Duan Haiou Zhang Zhi Sun Yuan Shen Xing Lin Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Beijing National Research Center for information science and Technology Tsinghua UniversityBeijing 100084China

Wireless sensing of the wave propagation direction from radio sources lays the foundation for communication,radar,navigation,***,the existing signal processing paradigm for the direction of arrival estimation requires the radio frequency electronic circuit to demodulate and sample the multichannel baseband signals followed by a complicated computing process,which places the fundamental limit on its sensing speed and energy ***,we propose the super-resolution diffractive neural networks(S-DNN)to process electromagnetic(EM)waves directly for the DOA estimation at the speed of *** multilayer meta-structures of S-DNN generate super-oscillatory angular responses in local angular regions that can perform the all-optical DOA estimation with angular resolutions beyond the diffraction *** spatial-temporal multiplexing of passive and reconfigurable S-DNNs is utilized to achieve high-resolution DOA estimation over a wide field of *** S-DNN is validated for the DOA estimation of multiple radio sources over 5 GHz frequency bandwidth with estimation latency over two to four orders of magnitude lower than the state-of-the-art commercial devices in *** results achieve the angular resolution over an order of magnitude,experimentally demonstrated with four times,higher than diffraction-limited *** also apply S-DNN’s edge computing capability,assisted by reconfigurable intelligent surfaces,for extremely low-latency integrated sensing and communication with low power *** work is a significant step towards utilizing photonic computing processors to facilitate various wireless sensing and communication tasks with advantages in both computing paradigms and performance over electronic computing.

关键词： beyond optical network

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Remote sensing and its applications using GNSS reflected signals:advances and prospects

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Satellite Navigation 2024年第1期5卷 10-51页

作者： Shuanggen Jin Adriano Camps Yan Jia Feng Wang Manuel Martin-Neira Feixiong Huang Qingyun Yan Shuangcheng Zhang Zhongyu Li Komi Edokossi Dongkai Yang Zhiyu Xiao Zhongmin Ma Weihua Bai Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai200030China School of Surveying and Land information Engineering Henan Polytechnic UniversityJiaozuo454003China Department of Signal Theory and Communications Technical University of CataloniaBarcelona08034Spain Department of Surveying and Geoinformatics Nanjing University of Posts and TelecommunicationsNanjing210023China School of Electronics and information Engineering Beihang UniversityBeijing100191China European Space Research and Technology centre(ESTEC) European Space Agency2200-AGNoordwijkThe Netherlands National Space science Center Chinese Academy of SciencesBeijing100190China School of Remote Sensing and Geomatics Engineering Nanjing University of Information Science and TechnologyNanjing210044China College of Geological Engineering and Geomatics Chang’an UniversityXi’an710054China University of Electronic science and Technology of China Chengdu611731China

The Global Navigation Satellite Systems(GNSS),including the US’s GPS,China’s BDS,the European Union’s Galileo,and Russia’s GLONASS,offer real-time,all-weather,any-time,anywhere and high precision observations by transmitting L band signals continuously,which have been widely used for positioning,navigation and *** the development of GNSS technology,it has been found that GNSS-reflected signals can be used to detect Earth’s surface characteristics together with other signals of *** this paper,the current status and latest advances are presented on Global Navigation Satellite System-Reflectometry(GNSS-R)in theory,methods,techniques and *** developments and progresses in GNSS-R instruments,theoretical modeling,and signal processing,ground and space-/air-borne experiments,parameters retrieval(*** speed,sea surface height,soil moisture,ice thickness),sea surface altimetry and applications in the atmosphere,oceans,land,vegetation,and cryosphere are given and reviewed in ***,the challenges in the GNSS-R development of each field are also ***,the future applications and prospects of GNSS-R are discussed,including multi-GNSS reflectometry,new GNSS-R receivers,GNSS-R missions,and emerging applications,such as mesoscale ocean eddies,ocean phytoplankton blooms,microplastics detection,target recognition,river flow,desert studies,natural hazards and landslides monitoring.

关键词： GNSS Reflectometry Remote sensing Environmental change

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