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SSRN 2023年

作者： Liao, Qi Wang, Dian Yang, Xiao He, Wei Yang, X. Peng, H.B. Wen, Y.H. School of Mechanical Engineering Sichuan University Chengdu China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu China School of of Mechanical Engineering Hebei University of Technology Tianjin China School of Manufacturing Science & Engineering China

It is not clear how coherent ordered nanoparticles affect characteristics of FCCHCP martensitic transformation in disordered alloys. In this paper, the precipitations of coherent ordered nanoparticles and their effects on the FCCHCP martensitic transformation were systematically investigated in a solution-treated Co24Ni6Si shape memory alloy. The results showed that both the coherent ordered L12 structured and L11 structured nanoparticles could precipitate even in the solution-treated Co24Ni6Si alloy followed by water quenching. The L12 structured nanoparticles strongly hindered the occurrence of stress-induced HCP martensitic transformation and its reverse transformation, but their hindrance dramatically reduced with the decrease of size when below 1.5 nm. The coherent ordered nanoparticles did not convert the nonthermoelastic FCCHCP martensitic transformation to the thermoelastic ones owing to absence of group-subgroup relation between the parent phase and martensite. A maximal recovery strain of 6.7% was obtained after only aging at 1073 K for 1 min. This value was 1~2% higher than the reported maximal ones in conventional FeMnSi-based alloys subjected to complicated thermomechanical treatments. The enhanced reversibility of HCP martensitic transformation could account for this larger recovery strain by the ultrafine coherent ordered L12 structured nanoparticles. © 2023, The Authors. All rights reserved.

关键词： Martensitic transformations

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Thinning air-water films stabilized by bacterial particles

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Acta Mechanica Sinica 2021年第1期37卷 27-34,I0001页

作者： Song Wu Yuehua Yang Hongyuan Jiang Hefei National Laboratory for Physical Science at the Microscale CAS Key Laboratory of Mechanical Behavior and Design of MaterialsDepartment of Modern MechanicsCAS Center for Excellence in Complex System MechanicsUniversity of Science and Technology of ChinaHefei230026China

The ability of particles to stabilize liquid films has broad applications in many fields,such as drug delivery,biofuel catalysis,and crude-oil *** mechanism of particles to stabilize emulsions has been widely ***,how particles affect the stability of suspension films is still ***,the dynamics of bacterial particles on free liquid films during evaporation is obtained by direct microscopic *** find that the initial concentration of the bacterial solution affects the evolution of the shapes and stabilities of liquid *** liquid film with a low bacterial concentration exhibits a drainage and rupture process similar to pure water,and bacteria would be evacuated during the evaporation of liquid ***,when the bacterial concentration is high,bacteria form a single-layer array in the center of the film and greatly enhance the stability of the liquid *** demonstrate that these two distinct film evaporation dynamics are caused by the difference in the lateral capillary force of the particles at different positions on the liquid film,which is not affected by the active motility of ***,our research reveals the critical role of bacteria concentration in stabilizing suspension liquid film.

关键词： Bacterial concentration Evaporation dynamics Film stability Lateral capillary force

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Experimental study on the sub-channel void fraction characteristics of bubbly flow in rod bundles

Experimental study on the sub-channel void fraction characte...

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2020 International Conference on Nuclear Engineering, ICONE 2020, collocated with the ASME 2020 Power Conference

作者： Ren, Quan-Yao Pu, Zeng-Ping Zheng, Mei-Yin Su, Min Chen, Ping Pan, Liang-Ming He, Hui He, Qing-Che Science and Technology on Reactor System Design Technology Laboratory Chengdu China Chongqing China

ISBN: (纸本)9780791883785

The gas-liquid two-phase flow behaviors are always associated with its dynamic void fraction, such as flow resistance, heat transfer coefficient, phase distribution, critical heat flux etc. As regard to the commercial PWR and BWR, rod bundles are the typical geometry, which contains many subchannels for coolant flowing. In present study, the sub-channel void fraction was measured in 5×5 rod bundles with the subchannel impedance void meter consisting of 12 strip electrodes. Based on the measured void fraction in different sub-channels, the void fraction dynamics, PDF (probability distribution function) and CDF (cumulative distribution function) curves were analyzed to make clear the effect of superficial gas and liquid velocity, flow development and casing tube. The empirical correlation for PDF of dynamic sub-channel void fraction has been developed, which showed good fitness with PDF and CDF curves and satisfying accuracy of averaged void fraction. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Void fraction

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Visual-Servo Based End-Effector Control for Continuum Robots 8

Visual-Servo Based End-Effector Control for Continuum Robots

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8th IEEE International Conference on Advanced Robotics and Mechatronics, ICARM 2023

作者： Chang, Le Kang, Rongjie Sun, Changchao Yuan, Peikang Wang, Tong Song, Zhibin Dai, Jian S. School of Mechanical Engineering Tianjin University Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin300072 China Institute for Robotics Southern University of Science and Technology Shenzhen China

ISBN: (纸本)9798350300178

Delicate manipulation for continuum robots remains challenging. The key is to establish a motion controller with real-time perception, fast response, and high precision. Integrating visual sensors into the system can enhance the precision of end position control while minimizing uncertainties in the robot model. In this paper, a depth camera is used to identify the Aruco code to provide pose information to the continuum robot. Then the end-effector is controlled to achieve horizontal linear displacement and plug into a socket based on the pose information. Based on experimental findings, it has been demonstrated that the control accuracy can achieve a level of precision in the centimeter range. The presented methods expand the potential scenarios of the continuum robot. © 2023 IEEE.

关键词： Position control

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Position-and-Force-Sensorless Control Considering Equivalent Mass Matrix and Cross-Coupling Factors 49

Position-and-Force-Sensorless Control Considering Equivalent...

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49th Annual Conference of the IEEE Industrial Electronics Society, IECON 2023

作者： Shimamoto, Keita Murakami, Toshiyuki Yaskawa Electric Corporation Tsukuba Research Laboratory Ibaraki Japan Graduate School of Science and Technology Keio University Yokohama Japan Keio University Department of System Design Engineering Yokohama Japan

ISBN: (纸本)9798350331820

This paper presents a hybrid position/force control with equivalent mass matrices for position-and-force-sensorless manipulators and the evaluation of the control system. Position and force estimation methods in the controller are cascaded to estimate the position and force according to the respective characteristics of the electrical and mechanical systems. The proposed controller is designed to reduce vibration of the force control axes' motion from the cross-coupling factors of the dq-axis inductance, which cause position estimation error, and the cross-coupling effects among control axes from equivalent mass matrices, which expresses the relationship between the workspace force and acceleration. The position estimation based on the voltage equation, including the cross-coupling factors, derives compensation terms of the estimation error. The cross-coupling effects between position and force control axes in the equivalent mass matrices are designed to suppress the undesired force response vibrations. The experimental results show that the proposed system kept contact with an object during the rubbing motion by a 4-degree-of-freedom manipulator without position and force sensors. The utilized equivalent mass matrix reduced the force vibration caused by the vibration of the position estimation. © 2023 IEEE.

关键词： Force control

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Representation Learning based and Interpretable reactor System Diagnosis Using Denoising Padded Autoencoder

arXiv

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arXiv 2022年

作者： Li, Chengyuan Qiu, Zhifang Yan, Zhangrui Li, Meifu Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Nuclear Power Institute of China Chengdu610213 China

With the mass construction of Gen III nuclear reactors, it is a popular trend to use deep learning (DL) techniques for fast and effective diagnosis of possible anomalies to ensure the safety of reactor systems under accidents. To improve the robustness of diagnostic model to crippled and noisy monitoring data, and to enhance the interpretability of the diagnostic outputs, this paper focuses on three aspects. First, a novel Denoising Padded Autoencoder (DPAE) model is proposed for representation extraction of monitoring data, and such representation extractor is effective on disturbed data with signal-to-noise ratios up to 25.0 and monitoring data missing up to 40.0%. Secondly, a diagnostic paradigm using DPAE encoder followed by shallow statistical learning algorithms is proposed, and such stepwise diagnostic approach is tested on disturbed datasets with 41.8% and 80.8% higher classification and regression task evaluation metrics, in comparison with the end-to-end diagnostic approaches. Finally, a hierarchical interpretation algorithm using SHAP and feature ablation is presented to analyze the importance of the input monitoring parameters and validate the effectiveness of the high importance parameters. The results of this study inform the development of robust, interpretable, intelligent reactor anomaly diagnosis systems in situations with high safety requirements. Copyright © 2022, The Authors. All rights reserved.

关键词： Monitoring

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Microstructure and mechanical properties of as-cast(CuNi)100-xCox medium-entropy alloys

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China Foundry 2022年第6期19卷 511-518页

作者： Zhi-yong Yang Wei-ping Chen Liang-yan Hao Chen-liang Chu Da-hai Zeng Wei Xiong Zhi-qiang Fu Guangdong Key Laboratory for Advanced Metallic Materials Processing South China University of TechnologyGuangzhou 510640China Physical Metallurgy and Materials Design Laboratory Department of Mechanical Engineering and Materials ScienceUniversity of PittsburghPittsburghPA15261USA National Engineering Research Center of Near-net-shape Forming for Metallic Materials South China University of TechnologyGuangzhou 510640China

Microstructure and mechanical properties of non-equiatomic(CuNi)_(100-x)Co_(x)(x=15,20,25 and 30,at.%)medium-entropy alloys(MEAs)prepared by vacuum arc-melting were *** show that all the as-cast MEAs exhibit dual face-centered cubic(fcc)solid-solution phases with identical lattice constant,showing typical dendrite structure consisting of(Ni,Co)-rich phase in dendrites and Cu-rich phase in *** positive enthalpy of mixing among Cu and Ni-Co elements is responsible for the segregation of *** the increase of Co content,the volume fraction of(Ni,Co)-rich phase increases while the Cu-rich phase decreases,resulting in an increment of yield strength and a decrement of elongation for the(CuNi)_(100-x)Co_(x) ***-indentation test results show a great difference of microhardness between the two fcc phases of the *** measured microhardness value of the(Ni,Co)-rich phase is almost twofold as compared to that of the Cu-rich phase in all the(CuNi)_(100-x)Co_(x) *** the deformation of the MEAs,the Cu-rich phase bears the main plastic strain,whereas the(Ni,Co)-rich phase provides more pronounced strengthening.

关键词： medium-entropy alloys microstructure mechanical properties nano-indentation

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Research and Application of Nuclear reactor Computational Data Framework Based on HDF5 7th

Research and Application of Nuclear Reactor Computational Da...

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7th International Conference on Artificial Intelligence and Security, ICAIS 2021

作者： Lu, Wei Feng, Jintao Yang, Hao Zeng, Hui Pan, Junjie Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China School of Computer Science Chengdu University of Information Technology Chengdu610225 China School of Information and Software Engineering University of Electronic Science and Technology of China Chengdu610054 China

ISBN: (纸本)9783030786175

Nuclear reactor computing software need to process and maintain complex and massive data sets. In order to meet the requirement of mass data storage and processing in software, the data storage model and I/O method and programming interface of HDF5 (Hierarchical Data Format v5) are deeply studied. According to the data storage and processing requirement of typical nuclear reactor computing data such as assembly or core neutronics computing data and core thermal-hydraulic computing data, RCDF-H5 (reactor Compute Data Framework based on HDF5) is proposed. KYMRES (KYlin-2 Main RESults databank) and COMRES (COre Main RESults databank) are designed and implemented based on RCDF-H5. The performance tests show that RCDF-H5 has a higher I/O efficiency than conventional storage solutions. A new data storage and management solution for nuclear reactor computing software is provided. © 2021, Springer Nature Switzerland AG.

关键词： Digital storage

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Uncertainty in Bayesian Reinforcement Learning for Robot Manipulation Tasks with Sparse Rewards

Uncertainty in Bayesian Reinforcement Learning for Robot Man...

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2023 IEEE International Conference on Robotics and Biomimetics, ROBIO 2023

作者： Zheng, Li Li, Yanghong Wang, Yahao Bai, Guangrui He, Haiyang Dong, Erbao University of Science and Technology of China Cas Key Laboratory of Mechanical Behavior and Design of Materials Department of Precision Machinery and Precision Instrumentation 96 Jinzhai Road Anhui Province Hefei230026 China

ISBN: (纸本)9798350325706

This paper aims to explore the application of Bayesian deep reinforcement learning (BDRL) in robot manipulation tasks with sparse rewards, focusing on addressing the uncertainty in complex and sparsely rewarded environments. Conventional deep reinforcement learning (DRL) algorithms still face significant challenges in the context of robot manipulation tasks. To address this issue, this paper proposes a general algorithm framework called BDRL that combines reinforcement learning algorithms with Bayesian networks to quantify the model uncertainty, aleatoric uncertainty in neural networks, and uncertainty in the reward function. The effectiveness and generality of the proposed algorithm are validated through simulation experiments on multiple sets of different sparsely rewarded tasks, employing various advanced DRL algorithms. The research results demonstrate that the DRL algorithm based on the Bayesian network mechanism significantly improves the convergence speed of the algorithms in sparse reward tasks by accurately estimating the model uncertainty. © 2023 IEEE.

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Numerical study on unsteady characteristics of backflow vortex cavitation in an axial flow pump 8

Numerical study on unsteady characteristics of backflow vort...

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8th International Conference on Pumps and Fans, ICPF 2024

作者： Cai, Shuting Huang, Renfang An, Yi Wang, Yiwei Li, Ning Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of Mechanics Chinese Academy of Sciences Beijing100190 China School of Engineering Science University of Chinese Academy of Sciences Beijing100049 China Marine Design and Research Institute of China Shanghai200011 China Science and Technology on Waterjet Propulsion Laboratory Shanghai200011 China

Axial pumps play a crucial role in various industries such as agriculture, construction, and chemical engineering, exhibiting optimal efficiency under design conditions. However, in practical applications, these pumps often operate under off-design conditions due to environmental constraints, which would lead to a series of problems such as increased vibration, elevated noise levels, and a shortened pump lifespan, thereby endangering its safe and stable operation. This study addresses the issue by using a modified RNG k-Ε turbulence model combined with the Zwart cavitation model to simulate the cavitation characteristics of an axial-flow pump. The calculated cavitation characteristics are consistent with the experimental results, proving the exactitude of the numerical approach. A noteworthy observation is the severe cavitation occurrences at the backflow vortex, termed backflow vortex cavitation. This phenomenon undergoes inception, development, and eventual collapse constantly. According to the severity of the backflow vortex cavitation, different periods are divided into the bimodal stage and small-peak stage. Significantly, it is identified that the backflow vortex cavitation interacts with the impeller blades, as the impeller moves, thereby inducing blade vibration, and noise, and exacerbating cavitation erosion. The research results offer a theoretical foundation that is beneficial to enhancing the safe and stable operation of axial flow pumps. © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Vortex flow

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