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Roles of Upper-Level Descending Inflow in Moat Development in Simulated Tropical Cyclones with Secondary Eyewall Formation

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Advances in Atmospheric Sciences 2024年第6期41卷 1100-1114页

作者： nannan QIN Liguang WU Nanjing Joint Institute for Atmospheric Sciences Nanjing 210041China Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China Department of Atmospheric and Oceanic Sciences and Institute of Atmospheric Sciences Fudan UniversityShanghai 200438China Innovation Center of Ocean and Atmosphere System Zhuhai Fudan Innovation Research InstituteZhuhai 518057China

This study investigated the effects of upper-level descending inflow(ULDI)associated with inner-eyewall convection on the formation of the moat in tropical cyclones(TCs)with secondary eyewall formation(SEF).In our numerical experiments,a clear moat with SEF occurred in TCs with a significant ULDI,while no SEF occurred in TCs without a significant *** eyewall convection developed more vigorously in the control run.A ULDI occurred outside the inner-eyewall convection,where it was symmetrically *** ULDI was initially triggered by the diabatic warming released by the inner eyewall and later enhanced by the cooling below the anvil *** ULDI penetrated the outer edge of the inner eyewall with relatively dry air and prevented excessive solid-phase hydrometeors from being advected further *** produced extensive sublimation cooling of falling hydrometeors between the eyewall and the outer *** sublimation cooling resulted in negative buoyancy and further induced strong subsidence between the eyewall and the outer *** a result,a clear moat was *** of the moat in the ongoing SEF prevented the outer rainband from moving farther inward,helping the outer rainband to symmetrize into an outer *** the sensitivity experiment,no significant ULDI formed since the eyewall convection was weaker,and the eyewall anvil developed relatively lower,meaning the formation of a moat and thus an outer eyewall was less *** study suggests that a better-represented simulation of inner-eyewall convective structures and distribution of the solid-phase hydrometeors is important to the prediction of SEF.

关键词： tropical cyclone secondary eyewall formation upper-level descending inflow eyewall convection

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CMMCAN:Lightweight Feature Extraction and Matching Network for Endoscopic Images Based on Adaptive Attention

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Computers, Materials & Continua 2024年第8期80卷 2761-2783页

作者： nannan Chong Fan Yang School of Electronic and Information Engineering Hebei University of TechnologyTianjin300401China School of Information and Intelligence Engineering Tianjin Renai CollegeTianjin301636China

In minimally invasive surgery,endoscopes or laparoscopes equipped with miniature cameras and tools are used to enter the human body for therapeutic purposes through small incisions or natural ***,in clinical operating environments,endoscopic images often suffer from challenges such as low texture,uneven illumination,and non-rigid structures,which affect feature observation and *** can severely impact surgical navigation or clinical diagnosis due to missing feature points in endoscopic images,leading to treatment and postoperative recovery issues for *** address these challenges,this paper introduces,for the first time,a Cross-Channel Multi-Modal Adaptive Spatial Feature Fusion(ASFF)module based on the lightweight architecture of ***,a novel lightweight feature extraction and matching network based on attention mechanism is *** network dynamically adjusts attention weights for cross-modal information from grayscale images and optical flow images through a dual-branch Siamese *** extracts static and dynamic information features ranging from low-level to high-level,and from local to global,ensuring robust feature extraction across different widths,noise levels,and blur *** and local matching are performed through a multi-level cascaded attention mechanism,with cross-channel attention introduced to simultaneously extract low-level and high-level *** ablation experiments and comparative studies are conducted on the HyperKvasir,EAD,M2caiSeg,CVC-ClinicDB,and UCL synthetic *** results demonstrate that the proposed network improves upon the baseline EfficientViT-B3 model by 75.4%in accuracy(Acc),while also enhancing runtime performance and storage *** compared with the complex DenseDescriptor feature extraction network,the difference in Acc is less than 7.22%,and IoU calculation results on specific datasets outperform complex dense ***

关键词： Feature extraction and matching lightweighted network medical images endoscopic attention

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Analysis of piezoelectric semiconductor fibers under gradient temperature changes

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Applied Mathematics and Mechanics(English Edition) 2024年第2期45卷 311-320页

作者： Shuangpeng LI Ruoran CHENG nannan MA Chunli ZHANG Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China

Piezoelectric semiconductors(PSs)possess both semiconducting properties and piezoelectric coupling effects,making them optimal building blocks for semiconductor *** fiber-like structures have wide applications in multi-functional semiconductor *** this paper,a one-dimensional(1D)theoretical model is established to describe the piezotronic responses of a PS fiber under gradient temperature *** theoretical model aims to explain the mechanism behind the resistance change caused by such gradient temperature *** results demonstrate that a gradient temperature change significantly affects the physical fields within the PS fiber,and can induce changes in its surface *** provides important theoretical guidance on the development of piezotronic devices that are sensitive to temperature effects.

关键词： piezoelectric semiconductor(PS)fiber one-dimensional(1D)model piezotronic effect gradient temperature change

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Observing eddy dye patches induced by shear instabilities in the surf zone on a plane beach

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Acta Oceanologica Sinica 2024年第3期43卷 15-29页

作者： Chunping Ren nannan Fu Chong Yu Yuchuan Bai Kezhao Fang State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China College of Water Resource Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

The effects of surf zone eddy generated by alongshore currents on the deformation and transport of dye are still poorly understood,and related tracer release experiments are ***,a tracer release laboratory experiment was conducted under monochromatic,unidirectional incident waves with a large incident angle(30°)on a plane beach with a 1:100 slope in a large wave basin.A charge-coupled device suspended above the basin recorded the dye patch *** evolution of eddy dye patch was observed and the transport and diffusion were analyzed based on the collected ***,a linear instability numerical model was adopted to calculate the perturbation velocity field at the initial *** observation and image processing results show that surf zone eddy patches occurred and were separated from the original dye *** numerical analysis results demonstrate that the structure of the perturbation velocity field is consistent with the experimental observations,and that the ejection of eddy patches shoreward or offshore may be ascribed to the double vortex.

关键词： surf zone tracer release experiment evolution of eddy patch shear instability of alongshore currents

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Sustainable development of electroencephalography materials and technology

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SusMat 2024年第2期4卷 125-144页

作者： Ling Xiong nannan Li Yi Luo Lei Chen Institutes for Breast Health Medicine West China HospitalSichuan UniversityChengduChina Micro/Nano Fabrication Laboratory Microsystem and Terahertz Research CenterChina Academy of Engineering PhysicsChengduChina Institute of Electronic Engineering China Academy of Engineering PhysicsMianyangChina Department of Neurology Joint Research Institution of Altitude HealthWest China HospitalSichuan UniversityChengduChina

Electroencephalogram(EEG)is one of the most important bioelectrical signals related to brain activity and plays a crucial role in clinical *** by continuously expanding applications,the development of EEG materials and technology has attracted considerable ***,systematic analysis of the sustainable development of EEG materials and technology is still *** review discusses the sustainable development of EEG materials and ***,the developing course of EEG is introduced to reveal its significance,particularly in clinical ***,the sustainability of the EEG materials and technology is discussed from two main aspects:integrated systems and EEG *** integrated systems,sustainability has been focused on the developing trend toward mobile EEG systems and big-data monitoring/analyzing of EEG *** is related to miniaturized,wireless,portable,and wearable systems that are integrated with big-data modeling *** EEG electrodes and materials,sustainability has been comprehensively analyzed from three perspectives:performance of different material/structural categories,sustainablematerials for EEGelectrodes,and sustainable manufacturing *** addition,sustainable applications of EEG have been ***,the sustainable development of EEG materials and technology in recent decades is summarized,revealing future possible research directions as well as urgent challenges.

关键词： clinical medicine electroencephalography technology limitations and future directions materials and electrodes sustainable development

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A Cover-Independent Deep Image Hiding Method Based on Domain Attention Mechanism

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Computers, Materials & Continua 2024年第3期78卷 3001-3019页

作者： nannan Wu Xianyi Chen James Msughter Adeke Junjie Zhao School of Computer and Software Nanjing University of Information Science and TechnologyNanjing210044China School of Electronics and Information Engineering Nanjing University of Information Science and TechnologyNanjing210044China

Recently,deep image-hiding techniques have attracted considerable attention in covert communication and high-capacity information ***,these approaches have some *** example,a cover image lacks self-adaptability,information leakage,or weak *** address these issues,this study proposes a universal and adaptable image-hiding ***,a domain attention mechanism is designed by combining the Atrous convolution,which makes better use of the relationship between the secret image domain and the cover image ***,to improve perceived human similarity,perceptual loss is incorporated into the training *** experimental results are promising,with the proposed method achieving an average pixel discrepancy(APD)of 1.83 and a peak signal-to-noise ratio(PSNR)value of 40.72 dB between the cover and stego images,indicative of its high-quality ***,the structural similarity index measure(SSIM)reaches 0.985 while the learned perceptual image patch similarity(LPIPS)remarkably registers at ***,self-testing and cross-experiments demonstrate the model’s adaptability and generalization in unknown hidden spaces,making it suitable for diverse computer vision tasks.

关键词： Deep image hiding attention mechanism privacy protection data security visual quality

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Effects of Different Concentrations of Sulfate Ions on Carbonate Crude Oil Desorption:Experimental Analysis and Molecular Simulation

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Fluid Dynamics & Materials Processing 2024年第8期20卷 1731-1741页

作者： nannan Liu Hengchen Qi Hui Xu Yanfeng He School of Petroleum and Natural Gas Engineering Changzhou UniversityChangzhou213164China

Low salinity water containing sulfate ions can significantly alter the surface wettability of carbonate ***,the impact of sulfate concentration on the desorption of oil film on the surface of carbonate rock is still *** study examines the variations in the wettability of the surface of carbonate rocks in solutions containing varying amounts of sodium sulfate and pure *** problem is addressed in the framework of molecular dynamics simulation(Material Studio software)and *** experiment’s findings demonstrate that sodium sulfate can increase the rate at which oil moisture is turned into water *** final contact angle is smaller than that of pure *** results of the simulations show that many water molecules travel down the water channel under the influence of several powerful forces,including the electrostatic force,the van der Waals force and hydrogen bond,crowding out the oil molecules on the calcite’s surface and causing the oil film to *** relative concentration curve of water and oil molecules indicates that the separation rate of the oil film on the surface of calcite increases with the number of sulfate ions.

关键词： Carbonate rocks wettability sulfate ions concentration molecular simulation desorption

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A Note on the Signless Laplacian Spectral Ordering of Graphs with Given Size

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Journal of Mathematical Research with Applications 2024年第3期44卷 304-312页

作者： nannan LIU Shuguang GUO School of Mathematics and Statistics Qinghai Normal University School of Mathematics and Statistics Yancheng Teachers University

Abstract For a simple undirected graph G with fixed size m≥2k （k∈Z+） and maximum degree?（G）≤m-k,we give an upper bound on the signless Laplacian spectral radius q（G）of *** two connected graphs G1and G2with size m≥8,employing this upper bound,we prove that q（G1）>q（G2） if?（G1）>?（G2）+1 and■.For triangle-free graphs,we prove two stronger *** an application,we completely characterize the graph with maximal signless Laplacian spectral radius among all graphs with size m and circumference c for m≥max{2c,c+9},which partially answers the question proposed by Chen et ***[Linear Algebra Appl.,2022,645:123–136].

关键词： signless Laplacian spectral radius upper bound ordering size circumference

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Pyramid-resolution person restoration for cross-resolution person re-identification

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Science China(Information Sciences) 2024年第6期67卷 451-452页

作者： Chunlei PENG Bo WANG Decheng LIU nannan WANG Xinbo GAO State Key Laboratory of Integrated Services Networks Xidian University School of Cyber Engineering Xidian University School of Telecommunications Engineering Xidian University Chongqing Key Laboratory of Image Cognition Chongqing University of Posts and Telecommunications

Person images captured by surveillance cameras are typically with various resolutions and are susceptible to pose changes,occlusion and background variations,thus affecting the performance of person Re *** approaches[1,2]either use an image restoration model to restore the lowresolution images to obtain a corresponding high-resolution image,

关键词： Restoration

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Frequent recombination in Cynoglossus abbreviatus(Pleuronectiformes:Cynoglossidae)ribosomal 18S rDNA

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Acta Oceanologica Sinica 2024年第8期43卷 98-103页

作者： Li Gong Tingqi Jiang Bilin Hu Kaixin Wang nannan Zhang Zengliang Miao National Engineering Laboratory of Marine Germplasm Resources Exploration and Utilization Zhejiang Ocean UniversityZhoushan 316022China Marine Science and Technology College Zhejiang Ocean UniversityZhoushan 316022China

The conventional theory of concerted evolution has been used to explain the lack of sequence variation in ribosomal RNA(rRNA)genes across diverse eukaryotic ***,recent investigations into rRNA genes in flatfish genome have resulted in controversial *** study focuses on 18S rRNA genes of the widely distributed tongue sole,Cynoglossus abbreviatus(Pleuronectiformes:Cynoglossidae),aiming to explore sequence *** distinct 18S rDNA sequence types(Type A,B,R1,R2,and R3)were identified,suggesting a departure from concerted evolution.A combination of general criteria and variations in highly conserved regions were employed to detect *** results pinpointed Type A sequences as potential pseudogenes due to significant sequence variations and deviations in secondary structure within highly conserved *** types(Type R1,R2,and R3)were identified as recombinants between Type A and B sequences,with simple crossing over and gene conversion as the most likely recombination *** findings not only contribute to rRNA pseudogene identification but also shed light on the evolutionary dynamics of rRNA genes in teleost genomes.

关键词： ribosomal RNA tongue sole non-concerted evolution pseudogene crossing over gene conversion

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