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Broadband high-efficiency dielectric metalenses based on quasi-continuous nanostrips

Opto-Electronic Advances 2024年第5期7卷 43-51页

作者： Xiaohu Zhang Qinmiao Chen Dongliang Tang Kaifeng Liu Haimo Zhang Lintong Shi Mengyao He Yongcai Guo Shumin Xiao Key Laboratory of optoelectronic Technology and Systems of the Education Ministry of china Chongqing UniversityChongqing 400044China Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic SystemsHarbin Institute of TechnologyShenzhen 518055China Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices School of Physics and ElectronicsHunan UniversityChangsha 410082China

Benefiting from the abrupt phase changes within subwavelength thicknesses,metasurfaces have been widely applied for lightweight and compact optical *** broadband and high-efficiency characteristics are highly attractive for the practical implementation of ***,current metasurface devices mostly adopt discrete micro/nano structures,which rarely realize both merits *** this paper,dielectric metasurfaces composed of quasi-continuous nanostrips are proposed to overcome this *** quasi-continuous nanostrips metasurface,a normal focusing metalens and a superoscillatory lens overcoming the diffraction limit are designed and experimentally *** quasi-continuous metadevices can operate in a broadband wavelength ranging from 450 nm to 1000nm and keep a high power *** average efficiency of the fabricated metalens reaches 54.24%,showing a significant improvement compared to the previously reported metalenses with the same *** proposed methodology can be easily extended to design other metadevices with the advantages of broadband and high-efficiency in practical optical systems.

关键词： broadband high-efficiency metalens sub-diffraction quasi-continuous

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Hyperspectral remote sensing identification of marine oil emulsions based on the fusion of spatial and spectral features

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Acta Oceanologica Sinica 2024年第3期43卷 139-154页

作者： Xinyue Huang Yi Ma Zongchen Jiang Junfang Yang School of Geography and Marine science Nanjing UniversityNanjing 210023China First Institute of Oceanography Ministry of Natural ResourcesQingdao 266061China Marine Telemetry Technology Innovation Center Ministry of Natural ResourcesQingdao 266061China Harbin Institute of Technology Harbin 150001China china University of Petroleum(East china) Qingdao 266061China

Marine oil spill emulsions are difficult to recover,and the damage to the environment is not easy to *** use of remote sensing to accurately identify oil spill emulsions is highly important for the protection of marine ***,the spectrum of oil emulsions changes due to different water *** remote sensing and deep learning can use spectral and spatial information to identify different types of oil ***,hyperspectral data can also cause information redundancy,reducing classification accuracy and efficiency,and even overfitting in machine learning *** address these problems,an oil emulsion deep-learning identification model with spatial-spectral feature fusion is established,and feature bands that can distinguish between crude oil,seawater,water-in-oil emulsion(WO),and oil-in-water emulsion(OW)are filtered based on a standard deviation threshold–mutual information *** oil spill airborne hyperspectral data,we conducted identification experiments on oil emulsions in different background waters and under different spatial and temporal conditions,analyzed the transferability of the model,and explored the effects of feature band selection and spectral resolution on the identification of oil *** results show the following.(1)The standard deviation–mutual information feature selection method is able to effectively extract feature bands that can distinguish between WO,OW,oil slick,and *** number of bands was reduced from 224 to 134 after feature selection on the Airborne Visible Infrared Imaging Spectrometer(AVIRIS)data and from 126 to 100 on the S185 data.(2)With feature selection,the overall accuracy and Kappa of the identification results for the training area are 91.80%and 0.86,respectively,improved by 2.62%and 0.04,and the overall accuracy and Kappa of the identification results for the migration area are 86.53%and 0.80,respectively,improved by 3.45%and 0.05.(3)The oil emulsion id

关键词： oil emulsions identification hyperspectral remote sensing feature selection convolutional neural network(CNN) spatial-temporal transferability

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Paleogene transgression process and environmental evolution in the deepwater area of the Baiyun Depression in the northern South china Sea

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Acta Oceanologica Sinica 2024年第4期43卷 15-24页

作者： Peijun Qiao Yuchi Cui Qiong Ma Qiang Yu Lei Shao State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China CNOOC Energy Technology&Services-Drilling&Production Co. CNOOC Central Laboratory Shenzhen BranchGuangdong 516000China

Multiple borehole samples are collected from the Baiyun Depression in deep-water area of the northern South china Sea(SCS)in an effort to reconstruct transgression processes during the Paleogene based on palynalgal *** study indicates that the Baiyun Depression generated a large group of palynopore assemblages and fluvial/lacustrine-related algae during the early and middle Eocene when the Wenchang Formation was *** entire depression was dominated by fluvial and lacustrine facies before *** eastern and southeastern sags transitioned to shallow marine environment by generating a large abundance of marine dinoflagellates during the Enping deposition of the late ***,the southern uplift zone simply yielded fluvial/lacustrine-related palynopores and algae,and was dominated by the fluvial and lacustrine environment during the early stage of the Enping Formation,prior to shifting into transitional setting in the later *** sags remained extensive fluvial and delta facies without existence of marine *** was until the depositional stage of the Zhuhai Formation(Oligocene)that the overall depression was strongly impacted from transgression *** eastern and southeastern sags were mainly under deep marine setting on a continental slope while northwestern and southern areas developed transitional *** distribution and accumulation patterns varied greatly among sub-sags,the overall Baiyun Depression was characterized by widespread development of marine *** should be noted that the northwestern sag also partly generated large-scale river delta *** to the eustatic rise and change of SCS spreading axis,the overall Baiyun Depression was mostly influenced by the deep marine environment on a continental slope during the early *** northwestern sag and southern uplift zone were found plentiful marine *** summary,transgression initiated from the ea

关键词： South china Sea Paleogene transgression sedimentary environment plant ecology

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A stable staggered-grid finite-difference scheme for acoustic modeling beyond conventional stability limit

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Petroleum science 2024年第1期21卷 182-194页

作者： Jing-Yi Xu Yang Liu national Key Laboratory of Petroleum Resources and Engineering China University of Petroleum(Beijing)Beijing 102249China china University of Petroleum(Beijing) Karamay CampusKaramay 834000XinjiangChina

Staggered-grid finite-difference(SGFD)schemes have been widely used in acoustic wave modeling for geophysical *** improved methods are proposed to enhance the accuracy of numerical ***,these methods are inevitably limited by the maximum Courant-Friedrichs-Lewy(CFL)numbers,making them unstable when modeling with large time sampling intervals or small grid *** solve this problem,we extend a stable SGFD scheme by controlling SGFD dispersion relations and maximizing the maximum CFL ***,to improve modeling stability,we minimize the error between the FD dispersion relation and the exact relation in the given wave-number region,and make the FD dispersion approach a given function outside the given wave-number area,thus breaking the conventional limits of the maximum CFL ***,to obtain high modeling accuracy,we use the SGFD scheme based on the Remez algorithm to compute the FD *** addition,the hybrid absorbing boundary condition is adopted to suppress boundary reflections and we find a suitable weighting coefficient for the proposed *** derivation and numerical modeling demonstrate that the proposed scheme can maintain high accuracy in the modeling process and the value of the maximum CFL number of the proposed scheme can exceed that of the conventional SGFD scheme when adopting a small maximum effective wavenumber,indicating that the proposed scheme improves stability during the modeling.

关键词： Acoustic wave Staggered-grid finite-difference(SGFD) modeling Courant-friedrichs-lewy(CFL)number Stability

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A typhoon-induced storm surge numerical model with GPU acceleration based on an unstructured spherical centroidal Voronoi tessellation grid

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Acta Oceanologica Sinica 2024年第3期43卷 40-47页

作者： Yuanyong Gao Fujiang Yu Cifu Fu Jianxi Dong Qiuxing Liu national Marine Environmental Forecasting Center Beijing 100081China Key Laboratory of Marine Hazards Forecasting Ministry of Natural ResourcesBeijing 100081China

Storm surge is often the marine disaster that poses the greatest threat to life and property in coastal *** and timely issuance of storm surge warnings to take appropriate countermeasures is an important means to reduce storm surge-related *** surge numerical models are important for storm surge *** further improve the performance of the storm surge forecast models,we developed a numerical storm surge forecast model based on an unstructured spherical centroidal Voronoi tessellation(SCVT)*** model is based on shallow water equations in vector-invariant form,and is discretized by Arakawa C *** SCVT grid can not only better describe the coastline information but also avoid rigid transitions,and it has a better global consistency by generating high-resolution grids in the key areas through transition *** addition,the simulation speed of the model is accelerated by using the openACC-based GPU acceleration technology to meet the timeliness requirements of operational ensemble *** only takes 37 s to simulate a day in the coastal waters of *** newly developed storm surge model was applied to simulate typhoon-induced storm surges in the coastal waters of *** hindcast experiments on the selected representative typhoon-induced storm surge processes indicate that the model can reasonably simulate the distribution characteristics of storm *** simulated maximum storm surges and their occurrence times are consistent with the observed data at the representative tide gauge stations,and the mean absolute errors are 3.5 cm and 0.6 h respectively,showing high accuracy and application prospects.

关键词： typhoon-induced storm surge numerical model GPU acceleration unstructured grid spherical centroidal Voronoi tessellation(SCVT)

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Retrieval of Antarctic sea ice freeboard and thickness from HY-2B satellite altimeter data

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Acta Oceanologica Sinica 2024年第3期43卷 87-101页

作者： Yizhuo Chen Xiaoping Pang Qing Ji Zhongnan Yan Zeyu Liang Chenlei Zhang Chinese Antarctic Center of Surveying and Mapping Wuhan UniversityWuhan 430079China Key Laboratory of Polar Surveying and Mapping science Ministry of Natural ResourcesWuhan 430079China Key Laboratory of Polar Environment Monitoring and Public Governance Ministry of EducationWuhan 430079China 4 School of Geography and Tourism Anhui Normal UniversityWuhu 241002China

Antarctic sea ice is an important part of the Earth’s atmospheric system,and satellite remote sensing is an important technology for observing Antarctic sea *** Chinese Haiyang-2B(HY-2B)satellite altimeter data could be used to estimate sea ice freeboard and provide alternative Antarctic sea ice thickness information with a high precision and long time series,as other radar altimetry satellites can,needs further *** paper proposed an algorithm to discriminate leads and then retrieve sea ice freeboard and thickness from HY-2B radar altimeter *** first collected the Moderate-resolution Imaging Spectroradiometer ice surface temperature(IST)product from the national Aeronautics and Space Administration to extract leads from the Antarctic waters and verified their accuracy through Sentinel-1 Synthetic Aperture Radar ***,a surface classification decision tree was generated for HY-2B satellite altimeter measurements of the Antarctic waters to extract leads and calculate local sea surface *** then estimated the Antarctic sea ice freeboard and thickness based on local sea surface heights and the static equilibrium ***,the retrieved HY-2B Antarctic sea ice thickness was compared with the CryoSat-2 sea ice thickness and the Antarctic Sea Ice Processes and Climate(ASPeCt)ship-based observed sea ice *** results indicate that our classification decision tree constructed for HY-2B satellite altimeter measurements was reasonable,and the root mean square error of the obtained sea ice thickness compared to the ship measurements was 0.62 *** proposed sea ice thickness algorithm for the HY-2B radar satellite fills a gap in this application domain for the HY-series satellites and can be a complement to existing Antarctic sea ice thickness products;this algorithm could provide long-time-series and large-scale sea ice thickness data that contribute to research on global climate change.

关键词： HY-2B satellite altimeter classification decision tree sea ice freeboard and thickness Antarctic waters

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The Middle Miocene lobe-shaped and band-shaped submarine fans in the Lingshui Sag,Qiongdongnan Basin:source-to-sink system,genesis and implication

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Acta Oceanologica Sinica 2024年第4期43卷 61-79页

作者： Xingzong Yao Congjun Feng Hongjun Qu Min Zhang Daming Li State Key Laboratory of Continental Dynamics Northwest UniversityXi’an 710069China Department of Geology Northwest UniversityXi’an 710069China Exploration and Development Technology Research Center of Yanchang Oilfield Co. Ltd.Yan’an 716000China Chexplor Resource Exploration Technology Co. Ltd.Huaibei 235000China

Deepwater oil and gas exploration is the key to sustainable breakthroughs in petroleum exploration *** Central Canyon gas field has confirmed the Lingshui Sag is a hydrocarbon-generating sag,and the deepwater reservoirs in the Lingshui Sag still have more fabulous oil and gas exploration *** on drilling data and three-dimensional(3D)seismic data,this paper uses seismic facies analysis,seismic attribute analysis,and coherence slice analysis to identify the types of submarine fans(lobe-shaped and band-shaped submarine fans)that developed in the Lingshui Sag during the Middle Miocene,clarify the source-to-sink system of the submarine fans and discuss the genesis mechanism of the submarine *** results show that:(1)the deepwater source-to-sink system of the Lingshui Sag in the Middle Miocene mainly consisted of a“delta(sediment supply)-submarine canyon(sediment transport channel)-submarine fan(deepwater sediment sink)”association;(2)the main factor controlling the formation of the submarine fans developed in the Lingshui Sag was on the relative sea level decline;and(3)the bottom current reworked the lobe-shaped submarine fan that developed in the northern Lingshui Sag and formed the band-shaped submarine fan with a greater sand *** paper aims to provide practical geological knowledge for subsequent petroleum exploration and development in the deepwater area of the Qiongdongnan Basin through a detailed analysis of the Middle Miocene submarine fan sedimentary system developed in the Lingshui Sag.

关键词： submarine fan source-to-sink system genesis mechanism Middle Miocene Lingshui Sag

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What induced the trend shift of mixed-layer depths in the Antarctic Circumpolar Current region in the mid-1980s?

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Acta Oceanologica Sinica 2024年第1期43卷 11-21页

作者： Shan Liu Jingzhi Su Huijun Wang Cuijuan Sui Key Laboratory of Marine Hazards Forecasting National Marine Environmental Forecasting CenterMinistry of Natural ResourcesBeijing 100081China Center for Earth System Modeling and Prediction of CMA Beijing 100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

An obvious trend shift in the annual mean and winter mixed layer depth(MLD)in the Antarctic Circumpolar Current(ACC)region was detected during the 1960–2021 *** trends stopped in mid-1980s,followed by a period of weak *** MLD deepening trend difference between the two periods were mainly distributed in the western areas in the Drake Passage,the areas north to Victoria Land and Wilkes Land,and the central parts of the South Indian *** newly formed ocean current shear due to the meridional shift of the ACC flow axis between the two periods is the dominant driver for the MLD trends shift distributed in the western areas in the Drake Passage and the central parts of the South Indian *** saltier trends in the regions north to Victoria Land and Wilkes Land could be responsible for the strengthening mixing processes in this region.

关键词： mixed layer depth trend shift Antarctic Circumpolar Current(ACC) flow axis

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An ensemble learning method to retrieve sea ice roughness from Sentinel-1 SAR images

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Acta Oceanologica Sinica 2024年第5期43卷 78-90页

作者： Pengyi Chen Zhongbiao Chen Runxia Sun Yijun He School of Marine sciences Nanjing University of Information Science&TechnologyNanjing 210044China East Sea Information Center of State Oceanic Administration Shanghai 200136China

Sea ice surface roughness(SIR)affects the energy transfer between the atmosphere and the ocean,and it is also an important indicator for sea ice *** obtain a small-scale SIR with high spatial resolution,a novel method is proposed to retrieve SIR from Sentinel-1 synthetic aperture radar(SAR)images,utilizing an ensemble learning ***,the two-dimensional continuous wavelet transform is applied to obtain the spatial information of sea ice,including the scale and direction of ice ***,a model is developed using the Adaboost Regression model to establish a relationship among SIR,radar backscatter and the spatial information of sea *** proposed method is validated by using the SIR retrieved from SAR images and comparing it to the measurements obtained by the Airborne Topographic Mapper(ATM)in the summer Beaufort *** determination of coefficient,mean absolute error,root-mean-square error and mean absolute percentage error of the testing data are 0.91,1.71 cm,2.82 cm,and 36.37%,respectively,which are ***,K-fold cross-validation and learning curves are analyzed,which also demonstrate the method’s applicability in retrieving SIR from SAR images.

关键词： 2-D Cauchy continuous wavelet transform(CWT) Adaboost Regression sea ice sea ice surface roughness

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Yuzaoea gen. nov., a new biraphid diatom(Bacillariophyceae)genus and its phylogenetic significance

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Acta Oceanologica Sinica 2024年第2期43卷 130-136页

作者： Honghan Liu Chenhong Li Lang Li Xuesong Li Lin Sun Junrong Liang Jun Zhang Yahui Gao Changping Chen Key Laboratory of Ministry of Education for Coastal and Wetland Ecosystems and School of Life sciences Xiamen UniversityXiamen 361102China State Key Laboratory of Marine Environmental science Xiamen UniversityXiamen 361102China Guangxi Key Laboratory of Marine Environmental science Guangxi Academy of Marine SciencesGuangxi Academy of SciencesNanning 530007China Beibu Gulf Marine Industry Research Institute Fangchenggang 538000China

The flexed frustules in pennate diatoms are usually associated with monoraphid diatoms. Interestingly, we found a biraphid diatom species with flexed frustules in an offshore intertidal beach environment on Weizhou Island,Beihai City, Guangxi Zhuang Autonomous Region, china. Therefore, based on morphological characteristics, we described a new genus of diatoms Yuzaoea sinensis gen. et sp. nov. CH Li, HH Liu, YH Gao & CP Chen. The frustule of this genus is characterized by heterogeneous frustule with one concave valve and one convex valve,complete raphe on both valves, straight and moderately eccentric raphe, uniseriate striae and girdle bands with a single row of areolae. The most identifying feature of this genus was the flexed frustule, which is rare in biraphid diatoms and common in monoraphid diatoms. We compared the morphometric characteristics of genus Yuzaoea with genus Rhoikoneis and several genera within the family Rhoicospheniaceae, including Rhoicosphenia,Campylopyxis, and Cuneolus. Phylogenetic analyses based on SSU rRNA and rbc L showed that the genus Yuzaoea was the sister group to the clade of Rhoicosphenia with a high support value(bootstrap values = 100%), and the clade “Yuzaoea+Rhoicosphenia” was sister to the clade of monoraphid diatoms, in which the genera Achnanthidium, Planothidium and some Cocconeis with high support values(bootstrap = 100%).Morphologically, the genus Yuzaoea shares many morphological features with monoraphid diatoms like genera Achnanthidium and Planothidium and the members within the Rhoicospheniaceae. Therefore, based on a combined morphological studies and phylogenetic results we suggested that this branch may represented the evolution of one kind monoraphid diatoms, from biraphid diatoms(e.g. genus Yuzaoea), to incompleted biraphid diatoms(e.g. genera Rhoicosphenia, Campylopyxis), to monoraphid diatoms(e.g. genera Achnanthidium and Planothidium).

关键词： biraphid diatom marine new genus Rhoicospheniaceae taxonomy Yuzaoea

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