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PD-YOLO:Colon Polyp Detection Model Based on Enhanced Small-Target Feature Extraction

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Computers, Materials & Continua 2025年第1期82卷 913-928页

作者： Yicong yu Kaixin Lin Jiajun Hong Rong-Guei Tsai yuanzhi Huang New Engineering Industry College Putian UniversityPutian351100China Engineering Research Center of Big Data Application in Private Health Medicine(Putian University) Fujian Province UniversityPutian351100China Computer College Guangdong University of Science&TechnologyDongguan523668China

In recent years,the number of patientswith colon disease has increased *** polyps are the precursor lesions of colon *** not diagnosed in time,they can easily develop into colon cancer,posing a serious threat to patients’lives and health.A colonoscopy is an important means of detecting colon ***,in polyp imaging,due to the large differences and diverse types of polyps in size,shape,color,etc.,traditional detection methods face the problem of high false positive rates,which creates problems for doctors during the diagnosis *** order to improve the accuracy and efficiency of colon polyp detection,this question proposes a network model suitable for colon polyp detection(PD-YOLO).This method introduces the self-attention mechanism CBAM(Convolutional Block Attention Module)in the backbone layer based on YOLOv7,allowing themodel to adaptively focus on key information and ignore the unimportant *** help themodel do a better job of polyp localization and bounding box regression,add the SPD-Conv(Symmetric Positive Definite Convolution)module to the neck layer and use deconvolution instead of *** results indicate that the PD-YOLO algorithm demonstrates strong robustness in colon polyp *** to the original YOLOv7,on the Kvasir-SEG dataset,PD-YOLO has shown an increase of 5.44 percentage points in AP@0.5,showcasing significant advantages over other mainstream methods.

关键词： Polyp detection YOLOv7 SPD-Conv CBAM deconvolution

Blind Channel Identification for Cyclic-Prefixed MIMO-OFDM Systems with Virtual Carriers

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China Communications 2020年第3期17卷 101-116页

作者： Jung-Lang yu Biling Zhang Yipu yuan wei-ting Hsu Graduate Institute of Applied Science and Engineering Fu Jen Catholic UniversityNew Taipei City 24205TaiwanChina The State Key Laboratory of Integrated Services Networks Xidian UniversityXian 710071China School of Network Education Beijing University of Posts and TelecommunicationsBeijing 100876China College of Physics and Information Engineering Quanzhou Normal UniversityQuanzhou 362000China Department of Electrical Engineering Fu Jen Catholic UniversityNew Taipei City 24205TaiwanChina

This paper applies the repetition index scheme(RIS)to the channel identification of cyclic prefixed(CP)multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM)systems with virtual carriers(VCs)in the environment of the number of receive antennas being no less than that of transmit *** VCs will cause a rank deficiency problem in computing the subspace *** the subcarrier mapping matrix,the received signal is simplified to remove the rank *** use the RIS scheme to generate many times of equivalent symbols so the channel identification can converge with few received OFDM *** RIS scheme will convert the white noise into non-white *** the Cholesky factorization,a noise whitening technique is developed to turn the non-white noise back to white *** further analyze the necessary conditions of identifiability of channel *** are performed to show the superiority of the proposed method.

关键词： OFDM MIMO virtual carrier channel identification Cholesky factorization

Spatio-temporal characteristics of population and economy in transitional geographic space at the southern end of"Hu Huan-yong Line"

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Journal of Mountain Science 2022年第2期19卷 350-364页

作者： DENG wei CHENG yu-fang yu Huan PENG Li KONG Bo HOU yu-ting School of Geography and Resource Science Sichuan Normal UniversityChengdu 610066China School of Earth Sciences Chengdu University of TechnologyChengdu 610059China Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China Institute of Aerospace Information Innovation Chinese Academy of SciencesBeijing 100094China

"Hu Huan-yong Line(Hu Line)"depicts a geographical pattern of China’s population *** essence is the regionality of humanland relationship and reflects basic characteristics and laws of human beings’adaptation to the natural *** the development of the times and the progress of modern science and technology,especially the rapid urbanization and construction of transportation network system in China,the connection between economic and geographical space has been continuously *** geographical transition zones from mountain areas to plains,i.e.,transitional geographical space,have promoted the changes in human-land relationships through population migration and *** Sichuan-yunnan provinces at the southern end of Hu Line as study area,this study analyzed the spatial correlation between population distribution and economy in this region,explored the pattern of geographical agglomeration and deagglomeration,and explained the changing characteristics of humanland relationship in transitional geographic space using global Moran’s I index,global regression model(GRM)and geographically weighted regression(GWR).The results show that population and Gross Domestic Product(GDP)have significant spatial dependence to this region,with obvious aggregation in geographical distribution and positive autocorrelation;comparing with the general least square model,the GWR model incorporating spatial effect was more suitable for revealing the distribution characteristics of geographical elements,with fine results and better fitting;the spatial model of population and GDP as well as the spatio-temporal evolution model of their changes,all of them strongly indicated that Normalized Difference Vegetation Index(NDVI)and road density were important factors governing the spatial differentiation of population and economy;under the rapid development of regional economy and continuous evolution of urban-rural relations,rural transformation and spa

关键词： Hu Huan-yong Line Spatial correlation Geographically weighted regression Population distribution Transitional geographic space

Integration of Electrical Properties and Polarization Loss Modulation on Atomic Fe–N‑RGO for Boosting Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第2期17卷 517-532页

作者： Kaili Zhang yuefeng Yan Zhen Wang Guansheng Ma Dechang Jia Xiaoxiao Huang yu Zhou State Key Laboratory of Precision Welding&Joining of Materials and Structures Harbin Institute of TechnologyHarbin 150001People’s Republic of China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001People’s Republic of China MIIT Key Laboratory of Advanced Structural‑Functional Integration Materials&Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001People’s Republic of China

Developing effective strategies to regulate graphene’s conduction loss and polarization has become a key to expanding its application in the electromagnetic wave absorption(EMWA)*** on the unique energy band structure of graphene,regulating its bandgap and electrical properties by introducing heteroatoms is considered a feasible ***,metal-nitrogen doping reduced graphene oxide(M–N-RGO)was prepared by embedding a series of single metal atoms M–N_(4) sites(M=Mn,Fe,Co,Ni,Cu,Zn,Nb,Cd,and Sn)in RGO using an N-coordination atom-assisted *** composites had adjustable conductivity and polarization to optimize dielectric loss and impedance matching for efficient EMWA *** results showed that the minimum reflection loss(RL_(min))of Fe–N-RGO reaches−74.05 dB(2.0 mm)and the maximum effective absorption bandwidth(EAB_(max))is 7.05 GHz(1.89 mm)even with a low filler loading of only 1 wt%.Combined with X-ray absorption spectra(XAFS),atomic force microscopy,and density functional theory calculation analysis,the Fe–N_(4) can be used as the polarization center to increase dipole polarization,interface polarization and defect-induced polarization due to d-p orbital hybridization and structural ***,electron migration within the Fe further leads to conduction loss,thereby synergistically promoting energy *** study demonstrates the effectiveness of metal-nitrogen doping in regulating the graphene′s dielectric properties,which provides an important basis for further investigation of the loss mechanism.

关键词： Electromagnetic wave absorption Fe-N-RGO Dipole polarization Conduction loss Impedance matching

The diapycnal mixing in the upper Pacific estimated from GTSPP observations

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Acta Oceanologica Sinica 2016年第1期35卷 46-52页

作者： DENG Zeng'an wei Guanghao yu ting wei Hongyu KANG Linchong HAN Luyao School of Marine Science and Technology Tianjin University Tianjin 300172 China National Marine Data and Information Service Tianjin 300171 China

Diapycnal mixing （DM） in the upper 600 m of the Pacific Ocean was estimated based on the huge amount of the observations from Global Temperature-Salinity Profile Programme （GTSPP）, using the strain version of the finescale parameterization. It is found that DM in each season exhibits similar distribution pattern, but differs in details. The intensification of DM is related to bottom roughness, surface near-inertial energy, and proximity to the equator. The intensified DM caused by rough topography shows in the profiles near the Mendocino fracture zone in the northeast Pacific, and the heightened DM caused by wind-generated near-inertial energy appears in the westerly region of the Southern Ocean. As compared to previous estimates, the DM estimate in this work has better spatial coverage and finer resolution, and more importantly it contains the seasonal variability, Furthermore, the resulting DM dataset is gridded, rendering it suitable for modeling applications.

关键词： diapycnal mixing GTSPP fine-scale parameterization Pacific

Optimization Strategies of Na_(3)V_(2)(PO_(4))_(3) Cathode Materials for Sodium‑Ion Batteries

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Nano-Micro Letters 2025年第2期17卷 204-251页

作者： Jiawen Hu Xinwei Li Qianqian Liang Li Xu Changsheng Ding yu Liu Yanfeng Gao School of Materials Science and Engineering Shanghai UniversityShanghai 200444People’s Republic of China Shanghai Institute of Ceramics Chinese Academy of SciencesShanghai 200050People’s Republic of China

Na_(3)V_(2)(PO_(4))_(3)(NVP)has garnered great attentions as a prospective cathode material for sodium-ion batteries(SIBs)by virtue of its decent theoretical capacity,superior ion conductivity and high structural ***,the inherently poor electronic conductivity and sluggish sodium-ion diffusion kinetics of NVP material give rise to inferior rate performance and unsatisfactory energy density,which strictly confine its further application in ***,it is of significance to boost the sodium storage performance of NVP cathode *** to now,many methods have been developed to optimize the electrochemical performance of NVP cathode *** this review,the latest advances in optimization strategies for improving the electrochemical performance of NVP cathode material are well summarized and discussed,including carbon coating or modification,foreign-ion doping or substitution and nanostructure and morphology *** foreign-ion doping or substitution is highlighted,involving Na,V,and PO_(4)^(3−)sites,which include single-site doping,multiple-site doping,single-ion doping,multiple-ion doping and so ***,the challenges and prospects of high-performance NVP cathode material are also put *** is believed that this review can provide a useful reference for designing and developing high-performance NVP cathode material toward the large-scale application in SIBs.

关键词： Sodium-ion batteries Na_(3)V_(2)(PO_(4))_(3) Cathode materials Electrochemical performance Optimization strategies

Co/Co_(7)Fe_(3)heterostructures with controllable alloying degree on carbon spheres as bifunctional electrocatalyst forrechargeable zinc-air batteries

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 476-487页

作者： Junkang Chen Yongyue Zhuang Yanxin Qiao yu Zhang Aihua yuan Hu Zhou School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Environmental and Chemical Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

Exploring efficient and nonprecious metal electrocatalysts of oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is crucial for developing rechargeable zinc-air batteries(ZABs).Herein,an alloying-degree control strategy was employed to fabricate nitrogen-doped carbon sphere(NCS)decorated with dual-phase Co/Co_(7)Fe_(3)heterojunctions(CoFe@NCS).The phase composition of materials has been adjusted by controlling the alloying *** optimal CoFe_(0.08)@NCS electrocatalyst displays a half-wave potential of 0.80 V for ORR and an overpotential of 283 mV at 10 mA·cm^(-2)for OER in an alkaline *** intriguing bifunctional electrocatalytic activity and durability is attributed to the hierarchically porous structure and interfacial electron coupling of highly-active Co_(7)Fe_(3)alloy and metallic Co *** the CoFe_(0.08)@NCS material is used as air-cathode catalyst of rechargeable liquid-state zinc-air battery(ZAB),the device shows a high peak power-density(157 mW·cm^(-2))and maintains a stable voltage gap over 150 h,outperforming those of the benchmark(Pt/C+RuO_(2))-based *** particular,the as-fabricated solid-state flexible ZAB delivers a reliable compatibility under different bending *** work provides a promising strategy to develop metal/alloy-based electrocatalysts for the application in renewable energy conversion technologies.

关键词： bifunctional electrocatalysts oxygen reduction reaction oxygen evolution reaction zinc-air battery metal/alloy carbon sphere

Unraveling the significance of cobalt on transformation kinetics,crystallography and impact toughness in high-strength steels

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 380-390页

作者： Yishuang yu Jingxiao Zhao Xuelin Wang Hui Guo Zhenjia Xie Chengjia Shang Collaborative Innovation Center of Steel Technology University of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China

This work reveals the significant effects of cobalt(Co)on the microstructure and impact toughness of as-quenched highstrength steels by experimental characterizations and thermo-kinetic *** results show that the Co-bearing steel exhibits finer blocks and a lower ductile-brittle transition temperature than the steel without ***,the Co-bearing steel reveals higher transformation rates at the intermediate stage with bainite volume fraction ranging from around 0.1 to *** improved impact toughness of the Co-bearing steel results from the higher dense block boundaries dominated by the V1/V2 variant ***,the addition of Co induces a larger transformation driving force and a lower bainite start temperature(BS),thereby contributing to the refinement of blocks and the increase of the V1/V2 variant *** findings would be instructive for the composition,microstructure design,and property optimization of high-strength steels.

关键词： high-strength steel cobalt transformation kinetics crystallography impact toughness

Broadband and perfect terahertz absorber based on multilayer metamaterial with cross-ring patterned structures

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Optoelectronics Letters 2025年第1期21卷 1-6页

作者： WEN Jin LIU Zhanzhi WU Zhengwei PAN yu ZHANG Ying School of Science Xi'an Shiyou University Shaanxi Key Laboratory of Measurement and Control Technology for Oil and Gas Wells

Broadband and perfect terahertz absorber based on multilayer metamaterial using cross-ring patterned structures is proposed and investigated. The structure of the absorber is double absorption layers consisting of a chromium cross ring and eight isosceles right triangles. The unique structure of the double absorbing layers excites the electric dipole multimode resonance, giving rise to high absorption performance. Meanwhile, the influence of construal parameters on absorber behavior is also discussed. The numerical results show that the absorption achieves over 90% ranging from 2.45 THz to 6.25 THz and 99% absorption in the range of 3.7—5.3 THz. The realization of broadband and perfect absorber is described using the impedance matching principle. It is obviously found that the absorber is insensitive to the high angle of incidence for both transverse electric(TE) and transverse magnetic(TM) polarizations. Compared with the former reports, this absorber has remarkable improved absorption efficiency and smaller period. The terahertz absorber may be found applications in the fields of energy capture and thermal detection.

关键词： Metamaterials