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An end-to-end instance segmentation method based on improved ConvNeXt V2

International Journal of Wireless and Mobile Computing 2024年第4期26卷 384-392页

作者： Wang, Wenlu Sun, Ying Xu, Manman Bai, Dongxu Huang, Li Zou, Chunlong Chen, Baojia Tang, Dalai Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education Wuhan University of Science and Technology Hubei Wuhan China Research Centre for Biomimetic Robot and Intelligent Measurement and Control Wuhan University of Science and Technology Hubei Wuhan China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and Technology Hubei Wuhan China College of Computer Science and Technology Wuhan University of Science and Technology Hubei Wuhan China Hubei Province Key Laboratory of Intelligent Information Processing and Real-time Industrial System Wuhan University of Science and Technology Hubei Wuhan China College of Mechanical Engineering Hubei University of Automotive Technology Hubei Shiyan China Hubei Key Laboratory of Hydroelectric Machinery Design and Maintenance China Three Gorges University Hubei Yichang China School of Computer Information Management Inner Mongolia University of Finance and Economics Hohhot China

In order to improve the efficiency of indoor mobile robots in locating and segmenting environmental instances, an instance segmentation method based on RTMDet is proposed. Firstly, the more powerful ConvNeXt V2 is used as the backbone network of the model, which improves the performance of the existing RTMDet model. Subsequently, NAS-FPN is used as a converged network to detect the network at any given time. Finally, AdamW is used as the model optimiser, which effectively solves the problem of excessive memory occupation when updating parameters and improves the performance of the model. The proposed method obtains the highest evaluation index in all cases. After training and testing on the Cityscapes data set, the recognition accuracy reaches 65.0%. © 2024 Inderscience Enterprises Ltd.

关键词： Statistical tests

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One-DOF Rigid and Flat-Foldable Origami Polyhedrons with Slits

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Acta Mechanica Solida Sinica 2023年第4期36卷 479-490页

作者： Yuehao Zhang Yuanqing Gu Yan Chen Ming Li Xiao Zhang School of Mechanical Engineering Tianjin UniversityTianjin 300350China Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300350China Space Structure and Mechanism Technology Laboratory of China Aerospace Science and Technology Group Co.Ltd Aerospace System Engineering ShanghaiShanghai 201109China

Rigid origami has great potential in aerospace applications,especially deployable polyhedrons with one degree of freedom(DOF)and flat-foldability,whose types are few to *** this paper,we create a novel foldable cube and a rhombic dodecahedron by introducing slits and diagonal creases to the surfaces,whose one-DOF rigid and flat-foldable properties are verified by kinematic ***,based on the isohedral quadrilateral transform,we project the creases and slits of the rhombic dodecahedron onto a tetrahedron to obtain a novel foldable tetrahedron that has two flat-foldable motion paths due to the existence of collinear *** the second path,unnecessary creases are removed,and an origami tetrahedron with simplified creases is *** origami tetrahedrons possess a small folded *** analysis reveals that these newly discovered origami polyhedrons are flat-foldable with one DOF,demonstrating favorable application prospects for space architectures and extraterrestrial habitats.

关键词： Rigid origami Flat-foldability Cube Rhombic dodecahedron Tetrahedron

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INVESTIGATION ON THE SIMULATION OF TURBULENT HEAT TRANSFER OF LIQUID METAL FLOW IN A NARROW RECTANGULAR CHANNEL 29

INVESTIGATION ON THE SIMULATION OF TURBULENT HEAT TRANSFER O...

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2022 29th International Conference on Nuclear Engineering, ICONE 2022

作者： Zhang, Xue Yu, Hongxing Deng, Jian Du, Sijia Zhang, Xilin Zou, Ziqiang Feng, Wenpei Zhang, Yaoxiang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China Hefei China

ISBN: (纸本)9780791886434

Liquid metal has the advantages of high boiling point and strong thermal conductivity and is selected as the coolant for a new generation nuclear system. In addition, the narrow rectangular channel is used in the small reactors or research reactors due to its compact structure and high heat transfer capacity. In order to accurately simulate the turbulent heat transfer of liquid metals in narrow rectangular channels, based on the relevant experimental data, this paper explored suitable numerical simulation methods. First of all, according to the research object, the appropriate experimental data was selected, and the geometric modeling, mesh division, and the mesh independence verification were carried out. It was ensured that the y+ meets the requirements of each turbulence model and wall treatment model. Several typical turbulence models and the wall treatment models were evaluated. For the low Prandtl number fluid such as liquid metal, it is necessary to select a suitable turbulent Prandtl number model in the RANS simulation. The sensitivity of the calculation results to the turbulent Prandtl number was analyzed. Finally, the existing turbulent Prandtl number models were evaluated. The suitable at different Pe was given based on experimental value, so that the turbulent heat transfer of liquid metal in a narrow rectangular channel can be accurately simulated. Copyright © 2022 by ASME.

关键词： Liquid metals

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THE DEVELOPMENT OF FISSION PRODUCT DIFFUSION/RELEASE MODEL FOR FAILED TRISO PARTICLES 30

THE DEVELOPMENT OF FISSION PRODUCT DIFFUSION/RELEASE MODEL F...

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30th International Conference on Nuclear Engineering, ICONE 2023

作者： Zheng, Junqiang He, Yanan Wu, Junmei Wu, Yingwei Li, Yuanming Tian, Wenxi Su, Guanghui Qiu, Suizheng School of Nuclear Science and Technology Xi'an Jiaotong University Xi'an China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace Xi'an Jiaotong University Xi'an China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institution of China Chengdu China

ISBN: (纸本)9784888982566

TRISO coated fuel particle has been adopted in the design of various reactors and Accident Tolerant Fuel (ATF) due to its excellent accident tolerant performance under high temperatures and other severe conditions. Accurately estimating fission product release from TRISO-coated fuel particles is indispensable to calculate the mechanistic source term. In most models, a bare kernel is substituted conservatively for failed particle. Thus, a theoretical method was proposed to describe the transport of fission products in intact and failed fuel particles. In this paper, to analyze the diffusion and release characteristics of intact TRISO-coated fuel particles' fission products, the fission products diffusion model of TRISO-coated fuel particles with thermal-mechanical coupling was established based on the COMSOL Multiphysics software and verified by the IAEA CRP-6 benchmark. The results indicate that the predictions by the developed fission product transport model is reasonable. Moreover, to analyze fission product release for failed partials, a conceptual theoretical method was proposed. The adsorption and desorption constraint model for fission products at the gas-solid interface and the gas phase diffusion model were added to the original model to analyze. Subsequently, predictions comparison for fission products' fractional release in failed particles between the proposed method and the Settings adopted in BISON were completed. The result suggests that the gas-phase diffusion model is feasible and seems favorable to simulate the diffusion of fission products in the failed coating layers. © 2023 by JSME.

关键词： Fission products

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Experimental Study on Aerosol Removal Effected by Spray Characterization 23rd

Experimental Study on Aerosol Removal Effected by Spray Char...

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23rd Pacific Basin Nuclear Conference, PBNC 2022

作者： Hu, Peizheng Xu, Zhen Wang, Junlong Tong, Lili Cao, Xuewu School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu China

ISBN: (纸本)9789811988981

The containment spray system is widely used in pressurized water reactor nuclear power plants, which can not only remove the heat in the containment but also remove the fission products suspended in the containment to reduce the discharge of radioactive substances to the environment during accident conditions. The aerosol removal behavior is affected by the spray droplet size distribution. The effect of different spray flow rates on aerosol removal is studied experimentally, and an improved evaluation model is established based on the spray droplet size distribution to analyze the efficiency of removal mechanisms. The experiments are carried out in the CATH (Containment Aerosol Thermal-Hydraulics) test facility with a total volume of 18.5 m3, where aerosols are injected and scrubbed by spray droplets. The spray droplets are generated by a full-cone spray nozzle at the volume flow rate of 0.4 m3/h and 0.6 m3/h, where droplet size distribution is measured by a Laser Diffractometer. Polydisperse particles of TiO2 are used to simulate the solid aerosol, whose diameters are in the range of 0.2 ~ 1.6 μm measured with an Aerosol Spectrometer. Experimental results show that the removal efficiency is higher for the larger particles, and the global removal efficiency of aerosols improved with the increase of spray flow rate from 0.4 to 0.6 m3/h. In addition, the removal efficiency of inertial impaction, interception, Brownian diffusion are quantitatively evaluated by the improved model, which shows that the effect of inertial impaction and interception is more significant for large particles. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Aerosols

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Analysis of the impact of long-term service of inverter devices on electromagnetic compatibility 2

Analysis of the impact of long-term service of inverter devi...

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2nd China Power Supply Society Electromagnetic Compatibility Conference, CPEMC 2024

作者： Zhang, Ruiheng Pei, Xuejun Meng, Jin Fan, Hongming Zhou, Peng Yuan, Yuzhang Power Electronics and Energy Management Key Laboratory Ministry of Education of China Huazhong University of Science and Technology Wuhan China National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan China

ISBN: (纸本)9798331509552

Taking the IGBT power module of the inverter device as the research object, finite element analysis technology was used to explore the influence of long-term service on the thermal characteristics and stress-strain of the IGBT module. At the same time, the influence of service aging on the electromagnetic compatibility performance of the device was studied, and the finite element simulation results were verified through accelerated aging experiments. The results showed that during the long-term operation of the IGBT module, due to the different thermal expansion coefficients of its materials, strain differences were found, ultimately leading to an increase in its ground capacitance, resulting in an increase in the amplitude of the common mode conducted noise of the device by 3dBμA in the frequency band after 20MHz. This study will provide theoretical guidance for the electromagnetic compatibility design of inverter devices for long-term service. ©2024 IEEE.

关键词： Insulated gate bipolar transistors (IGBT)

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Physics-based battery SOC estimation methods:Recent advances and future perspectives

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Journal of Energy Chemistry 2024年第2期89卷 27-40,I0003页

作者： Longxing Wu Zhiqiang Lyu Zebo Huang Chao Zhang Changyin Wei College of Mechanical Engineering Anhui Science and Technology UniversityChuzhou 233100AnhuiChina Hubei Key Laboratory of Power System Design and Test for Electrical Vehicle Hubei University of Arts and ScienceXiangyang 441053HubeiChina School of Internet Anhui UniversityHefei 230039AnhuiChina School of Mechanical and Electrical Engineering Guilin University of Electronic TechnologyGuilin 541004GuangxiChina

The reliable prediction of state of charge(SOC)is one of the vital functions of advanced battery management system(BMS),which has great significance towards safe operation of electric *** far,the empirical model-based and data-driven-based SOC estimation methods of lithium-ion batteries have been comprehensively discussed and reviewed in various ***,few reviews involving SOC estimation focused on electrochemical mechanism,which gives physical explanations to SOC and becomes most attractive candidate for advanced *** this reason,this paper comprehensively surveys on physics-based SOC algorithms applied in advanced ***,the research progresses of physical SOC estimation methods for lithium-ion batteries are thoroughly discussed and corresponding evaluation criteria are carefully ***,future perspectives of the current researches on physics-based battery SOC estimation are *** insights stated in this paper are expected to catalyze the development and application of the physics-based advanced BMS algorithms.

关键词： Lithium-ion batteries State of charge Electrochemical model Battery management system

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Dynamics and stability analysis of unbalance responses in mid-positioned electrically assisted turbocharger rotor

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International Journal of Mechanical system Dynamics 2024年第4期4卷 515-535页

作者： Mingyue Hu Shuqian Cao Xiaolin Cao Zhiyong Zhang Rixiu Men Zhenzhen You Tianyou Wang School of Mechanical Engineering Tianjin UniversityTianjinChina Tianjin Key Laboratory of Nonlinear Dynamics and Control TianjinChina National Key Laboratory of Vehicle Power System TianjinChina Science and Technology on Diesel Engine Turbocharging Laboratory China North Engine Research InstituteTianjinChina

Electrically assisted turbochargers(EAT)improve intake efficiency by motor-assisted compressor impeller rotation,enhancing the system's transient ***,the addition of motor rotor components has increased the number of unbalanced positions in the shaft system,leading to problems such as excessive compressor end vibration and complex changes in oil film *** evaluate the effects of unbalance in the motor rotor,along with the parameters of floating ring bearings(FRB),on the dynamic response of EAT,a finite element model of an EAT rotor supported by nonlinear FRB is developed,and the vibration response of the compressor end bearing is obtained by numerical *** results indicate:(1)In contrast to the effect of compressor and turbine unbalance,proper motor rotor unbalance is more effective in suppressing oil whirl instability in the high-speed operating ***,a new inner oil film whirl“instability interval”is also induced in the low-speed operating range,leading to an increase in the Y1 compressor-end amplitude at low and medium speeds,and this“instability interval”increases with the amount of unbalance.(2)When an oil whirl occurs in the oil film,the maximum eccentricity of the bearing surges and is greater than 0.3,which can be used as an effective threshold for determining whether the oil film is unstable in engineering applications.(3)A suitable outer oil-film clearance range should be 35–40μm,otherwise,a wide range of outer oil-film whirl instability *** the amount of unbalance and oil-film clearance to suppress the subsynchronous vibration of the EAT,provides a theoretical basis for the design of the dynamics of the nonlinear rotor bearing system and improves the stability of the turbocharger's operation.

关键词： electrically assisted turbocharger motor unbalance oil-film clearance rotor dynamics nonlinear vibration

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Bioinspired polysaccharide-based nanocomposite membranes with robust wet mechanical properties for guided bone regeneration

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national science Review 2024年第3期11卷 215-226页

作者： Jian-Hong Xiao Zhen-Bang Zhang JiaHao Li Si-Ming Chen Huai-Ling Gao YinXiu Liao Lu Chen ZiShuo Wang YiFan Lu YuanZhen Hou HengAn Wu DuoHong Zou Shu-Hong Yu Department of Chemistry New Cornerstone Science Laboratory Institute of Biomimetic Materials&Chemistry Anhui Engineering Laboratory of Biomimetic MaterialsDivision of Nanomaterials&Chemistry Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of China Department of Dental Implant Center Stomatologic Hospital and College Key Laboratory of Oral Diseases Research of Anhui Province Anhui Medical University CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Department of Oral Surgery College of Stomatology National Clinical Research Center for Oral DiseasesShanghai Key Laboratory of Stomatology Shanghai Research Institute of Stomatology Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Institute of Innovative Materials(I2M) Department of Chemistry Department of Materials Science and Engineering Southern University of Science and Technology

Polysaccharide-based membranes with excellent mechanical properties are highly desired. However, severe mechanical deterioration under wet conditions limits their biomedical applications. Here, inspired by the structural heterogeneity of strong yet hydrated biological materials, we propose a strategy based on heterogeneous crosslink-and-hydration（HCH） of a molecule/nano dual-scale network to fabricate polysaccharide-based nanocomposites with robust wet mechanical properties. The heterogeneity lies in that the crosslink-and-hydration occurs in the molecule-network while the stress-bearing nanofiber-network remains unaffected. As one demonstration, a membrane assembled by bacterial cellulose nanofiber-network and Ca2+-crosslinked and hydrated sodium alginate molecule-network is designed. Studies show that the crosslinked-and-hydrated molecule-network restricts water invasion and boosts stress transfer of the nanofiber-network by serving as interfibrous bridge. Overall, the molecule-network makes the membrane hydrated and flexible; the nanofiber-network as stress-bearing component provides strength and *** HCH dual-scale network featuring a cooperative effect stimulates the design of advanced biomaterials applied under wet conditions such as guided bone regeneration membranes.

关键词： bioinspiration heterogeneous crosslink-and-hydration dual-scale network nanocomposite membrane wet mechanical properties guided bone regeneration

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Multi-Level Robotic Pouring Using Offline Reinforcement Learning

Multi-Level Robotic Pouring Using Offline Reinforcement Lear...

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2024 IEEE International Conference on Robotics and Biomimetics, ROBIO 2024

作者： Zhang, Xiaoxiong Liu, Junwei Zhang, Wei School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen Key Laboratory of Control Theory and Intelligent Systems Shenzhen518055 China

ISBN: (纸本)9781665481090

This paper presents a novel learning-based method for a robotic manipulator to achieve liquid pouring across different liquid levels using only visual sensors. Previous works have relied on either online reinforcement learning or imitation learning, which are limited by sim-to-real gaps or data efficiency. In this paper, we propose to combine supervised learning and offline reinforcement learning, utilizing a human demonstration dataset containing only successful pouring at the highest level. Specifically, our approach employs supervised learning for a visual classifier, transforming the visual input into a categorical distribution over liquid levels. The offline reinforcement learning method is applied to a binary-conditioned control policy, which takes a binary signal and the robot's proprioception as inputs to determine the action. The binary signal indicates whether the desired liquid level has been reached based on the target liquid level. Through experiments, our method demonstrates superior effectiveness compared to a state-of-the-art imitation learning algorithm. Moreover, tests in unseen scenarios and multiple liquid level commands verify the generalization and transferability of our approach. © 2024 IEEE.

关键词： Self-supervised learning

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