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Two-Staged Method for Ice Channel Identification Based on Image Segmentation and Corner Point Regression

China Ocean Engineering 2024年第2期38卷 313-325页

作者： DONG Wen-bo ZHOU Li ding shi-feng WANG Ai-ming CAI Jin-yan School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Identification of the ice channel is the basic technology for developing intelligent ships in ice-covered waters,which is important to ensure the safety and economy of navigation.In the Arctic,merchant ships with low ice class often navigate in channels opened up by icebreakers.Navigation in the ice channel often depends on good maneuverability skills and abundant experience from the captain to a large extent.The ship may get stuck if steered into ice fields off the channel.Under this circumstance,it is very important to study how to identify the boundary lines of ice channels with a reliable method.In this paper,a two-staged ice channel identification method is developed based on image segmentation and corner point regression.The first stage employs the image segmentation method to extract channel regions.In the second stage,an intelligent corner regression network is proposed to extract the channel boundary lines from the channel region.A non-intelligent angle-based filtering and clustering method is proposed and compared with corner point regression network.The training and evaluation of the segmentation method and corner regression network are carried out on the synthetic and real ice channel dataset.The evaluation results show that the accuracy of the method using the corner point regression network in the second stage is achieved as high as 73.33%on the synthetic ice channel dataset and 70.66%on the real ice channel dataset,and the processing speed can reach up to 14.58frames per second.

关键词： ice channel ship navigation identification image segmentation corner point regression

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Regulation of the quantum barrier and carrier transport toward high-efficiency quasi-2D Dion-Jacobson tin perovskite solar cells

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Journal of Energy Chemistry 2024年第8期95卷 200-207页

作者： Huanhuan Yao Chang shi Tai Wu Shurong Wang Mingyu Yin Liming ding Yong Hua feng Hao School of Materials and Energy University of Electronic Science and Technology of China College of Chemistry and Molecular Engineering Peking University Yunnan Key Laboratory for Micro/Nano Materials & Technology School of Materials and Energy Yunnan University Center for Excellence in Nanoscience (CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication (CAS) National Center for Nanoscience and Technology

Quasi-2D Dion-Jacobson（DJ） tin halide perovskite has attracted much attention due to its elimination of Van der Waals gap and enhanced environmental stability.However,the bulky organic spacers usually form a natural quantum well structure,which brings a large quantum barrier and poor film quality,further limiting the carrier transport and device performance.Here,we designed three organic spacers with different chain lengths(ethylenediamine（EDA）,1,3-propanediamine（PDA）,and 1,4-butanediamine（BDA）) to investigate the quantum barrier dependence.Theoretical and experimental characterizations indicate that EDA with short chain can reduce the lattice distortion and dielectric confinement effect,which is beneficial to the effective dissociation of excitons and the inhibition of trap-free non-radiative relaxation.In addition,EDA cation shows strong interaction with the inorganic octahedron,realizing large aggregates in precursor solution and high-quality films with improved structural stability.Furthermore,femtosecond transient absorption proves that EDA cations can also weaken the formation of small n-phases with large quantum barrier to achieve effective carrier transport between different nphases.Finally,the quasi-2D DJ（EDA）FA9Sn10I31solar cells achieves a 7.07% power conversion efficiency with good environment stability.Therefore,this work sheds light on the regulation of the quantum barrier and carrier transport through the chain length of organic spacer for qua si-2D DJ lead-free perovskites.

关键词： Carrier transport Chain lengths Lattice distortion Organic spacers Quantum well

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Large magnetostriction of Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composites in a wide temperature range

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Journal of Rare Earths 2024年第4期42卷 705-709页

作者： Hehe ding Yangguang shi Shaolong Tang MIIT Key Laboratory of Aerospace Information Materials and Physics Department of Applied PhysicsNanjing University of Aeronautics and AstronauticsNanjing210016China National Laboratory of Solid State Microstructures Nanjing UniversityNanjing210093China

We report the magnetostrictive performance of the Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composites.Measurement of M?ssbauer spectra and the XRD results indicate that the easy magnetic direction of the Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)compound is alongdirection with spontaneous magnetostrictionλ111 of1900 ppm.The-oriented Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composites with particle volume fractions of20 vol%-55 vol%were prepared.Magnetization measurements demonstrate that the composite is highly anisotropic.The raw material cost of Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)is about 85%of that of the Terfenol-D(Tb_(0.3)Dy_(0.7)Fe_(2))composition.Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composites possess comparable magnetostriction with those composites made of Tb_(0.3)Dy_(0.7)Fe_(2)particles.At room temperature,the magnetostrictionλ_Ⅱof the Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93)/epoxy composite reaches 420 ppm at a low field of 80 kA/m and about1000 ppm at 239 kA/m.In addition,the composite exhibits a large saturation magnetostrictionλ_Ⅱover1200 ppm from 300 to 100 K,suggesting its potential applications as a low-cost magnetostrictive material in a wide temperature range.Therefore,the current study offers an opportunity to widen the operating temperature range of the magnetostrictive composite.

关键词： Magnetostrictive composite Nd_(0.2)Tb_(0.3)Dy_(0.5)Fe_(1.93) Wide temperaturerange Laves phase Rare earths

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Effect of tungsten carbide particles on microstructure and mechanical properties of Cu alloy composite bit matrix

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Journal of Iron and Steel Research(International) 2024年第2期31卷 519-530页

作者： ding-qian Dong feng-yuan He Xin-hui Chen Hui Li Kai-hua shi Hui-wen Xiong Xin Xiang Li Zhang College of Mechanical Engineering Sichuan University of Science and EngineeringZigong643000SichuanChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083HunanChina Zigong Cemented Carbide Co. Ltd.Zigong643011SichuanChina Material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Science and EngineeringZigong643000SichuanChina

Copper alloy composite bit matrix was prepared by pressureless vacuum infiltration,using at least one of the three kinds of tungsten carbide particles,for example,irregular cast tungsten carbide,monocrystalline tungsten carbide and sintered reduced tungsten carbide particles.The effects of powder particle morphology,particle size and mass fraction of tungsten carbide on the microstructure and mechanical properties of copper alloy composite were investigated by means of scanning electron microscopy,X-ray diffraction and abrasive wear test in detail.The results show that tungsten carbide morphology and particle size have obvious effects on the mechanical properties of copper alloy composites.Cast tungsten carbide partially dissolved in the copper alloy binding phase,and layers of Cu_(0.3)W_(0.5)Ni_(0.1)Mn_(0.1)C phase with a thickness of around 8–15μm were formed on the edge of the cast tungsten carbide.When 45%irregular crushed fine cast tungsten carbide and 15%monocrystalline cast tungsten carbide were used as the skeleton,satisfactory comprehensive performance of the reinforced copper alloy composite bit matrix was obtained,with the bending strength,impact toughness and hardness reaching 1048 MPa,4.95 J/cm^(2) and 43.6 HRC,respectively.The main wear mechanism was that the tungsten carbide particles firstly protruded from the friction surface after the copper alloy matrix was worn,and then peeled off from the matrix when further wear occurred.

关键词： Polycrystalline diamond compact Pressureless vacuum infiltration Copper alloy composite bit matrix Microstructure characterization Abrasive wear behavior

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Mesenchymal stem cell-derived extracellular vesicles in skin wound healing:roles,opportunities and challenges

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Military Medical Research 2024年第3期11卷 400-429页

作者： Jia-Yi ding Min-Jiang Chen Ling-feng Wu Gao-feng Shu shi-Ji Fang Zhao-Yu Li Xu-Ran Chu Xiao-Kun Li Zhou-Guang Wang Jian-Song Ji Key Laboratory of Imaging Diagnosis and Minimally Invasive Intervention Research Institute of Imaging Diagnosis and Minimally Invasive Intervention Researchthe Fifth Affiliated Hospital of Wenzhou Medical UniversityZhejiangLishui 323000China Oujiang Laboratory(Zhejiang Lab for Regenerative Medicine Vision and Brain Health)School of Pharmaceutical ScienceWenzhou Medical UniversityWenzhou 325035ZhejiangChina Clinical College of the Affiliated Central Hospital School of MedicineLishui UniversityLishui 323000ZhejiangChina Department of Overseas Education College Jimei UniversityXiamen 361021FujianChina Department of Medicine II Internal MedicineCardio-Pulmonary Institute(CPI)Universities of Giessen and Marburg Lung Center(UGMLC)Member of the German Center for Lung Research(DZL)Justus-Liebig University Giessen35392 GiessenGermany Pulmonary and Critical Care Department of Medicine VInternal MedicineInfectious Diseases and Infection ControlUniversities of Giessen and Marburg Lung Center(UGMLC)Member of the German Center for Lung Research(DZL)Justus-Liebig University Giessen35392 GiessenGermany

Skin wounds are characterized by injury to the skin due to trauma,tearing,cuts,or contusions.As such injuries are common to all human groups,they may at times represent a serious socioeconomic burden.Currently,increasing numbers of studies have focused on the role of mesenchymal stem cell(MSC)-derived extracellular vesicles(EVs)in skin wound repair.As a cell-free therapy,MSC-derived EVs have shown significant application potential in the field of wound repair as a more stable and safer option than conventional cell therapy.Treatment based on MSC-derived EVs can significantly promote the repair of damaged substructures,including the regeneration of vessels,nerves,and hair follicles.In addition,MSC-derived EVs can inhibit scar formation by affecting angiogenesis-related and antifibrotic pathways in promoting macrophage polarization,wound angiogenesis,cell proliferation,and cell migration,and by inhibiting excessive extracellular matrix production.Additionally,these structures can serve as a scaffold for components used in wound repair,and they can be developed into bioengineered EVs to support trauma repair.Through the formulation of standardized culture,isolation,purification,and drug delivery strategies,exploration of the detailed mechanism of EVs will allow them to be used as clinical treatments for wound repair.In conclusion,MSCderived EV-based therapies have important application prospects in wound repair.Here we provide a comprehensive overview of their current status,application potential,and associated drawbacks.

关键词： Mesenchymal stem cell(MSC) Extracellular vesicles(EVs) Wound repair Engineered nanoparticles

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Stability of the Phase Separation State for Compressible Navier-Stokes/Allen-Cahn System

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Acta Mathematicae Applicatae Sinica 2024年第1期40卷 45-74页

作者： Ya-zhou Chen Hakho Hong Xiao-ding shi Department of Mathematics College of Mathematics and PhysicsBeijing University of Chemical TechnologyBeijing100029China Institute of Mathematics State Academy of SciencesPyongyangKorea

This paper is concerned with the large time behavior of the Cauchy problem for Navier-Stokes/AllenCahn system describing the interface motion of immiscible two-phase flow in 3-D. The existence and uniqueness of global solutions and the stability of the phase separation state are proved under the small initial perturbations. Moreover, the optimal time decay rates are obtained for higher-order spatial derivatives of density,velocity and phase. Our results imply that if the immiscible two-phase flow is initially located near the phase separation state, then under small perturbation conditions, the solution exists globally and decays algebraically to the complete separation state of the two-phase flow, that is, there will be no interface fracture, vacuum, shock wave, mass concentration at any time, and the interface thickness tends to zero as the time t → +∞.

关键词： Navier-Stokes/Allen-Cahn system existence uniqueness large time behavior decay rate

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Chord length sampling correction analysis for dispersion fuel in Monte Carlo simulation

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Nuclear Science and Techniques 2024年第4期35卷 57-64页

作者： Zhao-Yu Liang ding She Yu-Tong Wen Lei shi Institute of Nuclear and New Energy Technology(INET) Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of EducationTsinghua UniversityBeijing 100084China

Dispersion fuels,knowned for their excellent safety performance,are widely used in advanced reactors,such as hightemperature gas-cooled reactors.Compared with deterministic methods,the Monte Carlo method has more advantages in the geometric modeling of stochastic media.The explicit modeling method has high computational accuracy and high computational cost.The chord length sampling(CLS)method can improve computational efficiency by sampling the chord length during neutron transport using the matrix chord length?s probability density function.This study shows that the excluded-volume effect in realistic stochastic media can introduce certain deviations into the CLS.A chord length correction approach is proposed to obtain the chord length correction factor by developing the Particle code based on equivalent transmission probability.Through numerical analysis against reference solutions from explicit modeling in the RMC code,it was demonstrated that CLS with the proposed correction method provides good accuracy for addressing the excludedvolume effect in realistic infinite stochastic media.

关键词： Stochastic media Monte Carlo Chord length sampling Excluded-volume effect Chord length correction

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Effect of hot isostatic pressure on the microstructure and tensile properties of γ'-strengthened superalloy fabricated through induction-assisted directed energy deposition

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1089-1097页

作者： Jianjun Xu Hanlin ding Xin Lin feng Liu Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 MPa,and 3 h).Results show that the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ phases in interdendritic and dendritic core regions.After HIP,grain morphology changed negligibly,whereas the size of the γ’ phase became increasingly even.After further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ phase in the as-deposited and HIPed samples presented a bimodal size distribution,whereas that in the as-deposited sample showed a size that remained uneven.The comparison of tensile properties revealed that the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’phases,especially large cubic γ’ phases.Finally,the relationship between phase transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.

关键词： directed energy deposition Ni-based superalloys high-temperature preheating hot isostatic pressing microstructure tensile properties

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Sound event localization and detection based on deep learning

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Journal of Systems Engineering and Electronics 2024年第2期35卷 294-301页

作者： ZHAO Dada ding Kai QI Xiaogang CHEN Yu feng Hailin School of Mathematics and Statistics Xidian UniversityXi’an 710071China Science and Technology on Near-Surface Detection Laboratory Wuxi 214035China

Acoustic source localization(ASL)and sound event detection(SED)are two widely pursued independent research fields.In recent years,in order to achieve a more complete spatial and temporal representation of sound field,sound event localization and detection(SELD)has become a very active research topic.This paper presents a deep learning-based multioverlapping sound event localization and detection algorithm in three-dimensional space.Log-Mel spectrum and generalized cross-correlation spectrum are joined together in channel dimension as input features.These features are classified and regressed in parallel after training by a neural network to obtain sound recognition and localization results respectively.The channel attention mechanism is also introduced in the network to selectively enhance the features containing essential information and suppress the useless features.Finally,a thourough comparison confirms the efficiency and effectiveness of the proposed SELD algorithm.Field experiments show that the proposed algorithm is robust to reverberation and environment and can achieve higher recognition and localization accuracy compared with the baseline method.

关键词： sound event localization and detection(SELD) deep learning convolutional recursive neural network(CRNN) channel attention mechanism

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Inflammatory Factor IL1αInduces Aberrant Astrocyte Proliferation in Spinal Cord Injury Through the Grin2c/Ca2+/CaMK2b Pathway

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Neuroscience Bulletin 2024年第4期40卷 421-438页

作者： Yu Xia Lu ding Changlin Zhang Qi Xu Ming shi Tianshun Gao feng-Quan Zhou David Y.B.Deng Scientific Research Center The Seventh Affiliated Hospital of Sun Yat-sen UniversityShenzhen518107China Department of Gynecology The Seventh Affiliated Hospital of Sun Yat-sen UniversityShenzhen518107China Pelvic Floor Disorders Center The Seventh Affiliated Hospital of Sun Yat-sen UniversityShenzhen518107China Big Data Center The Seventh Affiliated Hospital of Sun Yat-sen UniversityShenzhen518107China Sir Run Run Shaw Hospital Zhejiang University School of MedicineHangzhou310016China Orthopaedic and Neurological Repair Center The Seventh Affiliated Hospital of Sun Yat-sen UniversityShenzhen518107China

Spinal cord injury(SCI)is one of the most devastating traumas,and the aberrant proliferation of astrocytes usually causes neurological deficits.However,the mechanism underlying astrocyte over-proliferation after SCI is unclear.Grin2c(glutamate ionotropic receptor type 2c)plays an essential role in cell proliferation.Our bioinformatic analysis indicated that Grin2c and Ca2+transport functions were inhibited in astrocytes after SCI.Suppression of Grin2c stimulated astrocyte proliferation by inhibiting the Ca2+/calmodulin-dependent protein kinase 2b(CaMK2b)pathway in vitro.By screening different inflammatory factors,interleukin 1α(IL1α)was further found to inhibit Grin2c/Ca2+/CaMK2b and enhance astrocyte proliferation in an oxidative damage model.Blockade of IL1αusing neutralizing antibody resulted in increased Grin2c expression and the inhibition of astrocyte proliferation post-SCI.Overall,this study suggests that IL1αpromotes astrocyte proliferation by suppressing the Grin2c/Ca2+/CaMK2b pathway after SCI,revealing a novel pathological mechanism of astrocyte proliferation,and may provide potential targets for SCI repair.

关键词： IL1α Grin2c Astrocyte Spinal cord injury

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