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The Calculation Method of Neutron Transport Equation and its Conjugate Equation Based on Finite Deconvolution Neural Network

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SSRN 2022年

作者： Li, Xiangyu Cheng, Kun Huang, Tao Tan, Sichao Heilongjiang Provincial Key Laboratory of Nuclear Power System & Equipment Harbin Engineering University Harbin15001 China College of Nuclear Science and Technology Harbin Engineering University Harbin150001 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

Aiming at the problem that the current neutron transport equation solving method, which is mainly numerical calculation, takes too long to calculate the inverse of the stiffness matrix, this paper designs a shallow neural network algorithm based on finite deconvolution neural network, which does not need to calculate the inverse matrix for the sti ness matrix or use other iterative algorithms. The algorithm uses a deconvolution neural network algorithm as the basic structure, replaces the deconvolution kernel with the finite volume method, and uses the calculation equation of reactor power as the loss function. The gradient descent method and the power residual are used to update the algorithm parameters to ensure algorithm convergence. The algorithm can use the neutron transport equation and its conjugate equation to calculate the distribution of neutron flux density and neutron importance in the space. © 2022, The Authors. All rights reserved.

关键词： Numerical methods

On the Theory of Atomic Relaxation in Twisted Van Der Waals Bilayers with Out-of-Plane Deformation

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SSRN 2024年

作者： Zhang, Baidu Qiu, Wei Liao, Xiangbiao He, Linghui Ni, Yong 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 Anhui Hefei230026 China Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology Beijing100081 China

The effects of out-of-plane deformation on atomic relaxation in twisted van der Waals bilayers are investigated by comprehensive multiscale modeling and simulations. The model integrates the DFT-informed generalized stacking-fault energy for interlayer interaction between layers and the Föppl–von Kármán plate theory for elastic energy in each layer with minimization of the total free energy for atomic relaxation governed by a gradient flow method. Our simulation results elucidate twist-angle dependent moiré pattern, strain field, tortional displacement field and stacking domain structures, in good agreement with recent experimental observations. In particular, we derive the strain soliton solution at a small twist angle and the elastic solution at a large twist angle for the reconstructed van der Waals bilayer with out-of-plane deformation. These results show that out-of-plane deformation not only narrows the strain soliton width but also induces substantial alterations in the strain field, local rotation, and stacking structures. Our findings reveal the pivotal role played by out-of-plane deformation in the atomic relaxation of twisted van der Waals bilayers, particularly at smaller twist angles. The intricate interplay between in-plane atomic relaxation and out-of-plane deformation provides opportunities for strain engineering in twisted van der Waals bilayers. © 2024, The Authors. All rights reserved.

关键词： Atoms

Biomimetic Composite Tendon and Pneumatic Actuation for Soft Manipulator: Balancing High Load-Bearing Capacity, Repetitive Precision, and Active Softening Contact Safety

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SSRN 2024年

作者： Li, Xianglong Zhang, Shouyi Xiong, Quan Sui, Dongbao Zheng, Tianjiao Zhang, Qinghua Wang, Ziqi Luan, Lingkai Zhao, Jie Zhu, Yanhe State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150001 China Department of Biomedical Engineering National University of Singapore Singapore117583 Singapore Ji Hua Laboratory Foshan528200 China Harbin University of Science and Technology Harbin150001 China

Soft manipulator is a prominent research area in the field of soft robotics, but designing a soft manipulator capable of serving human life remains challenging, facing issues such as low motion robustness and poor accuracy. The trunk of an elephant, a unique biological tissue in nature, is characterized by its flexibility, strong load-bearing capacity, and dexterous yet soft tip, distinct from skeletal-dependent movements. Inspired by the thrust-deformation mechanism of the elephant trunk under multi-muscle action, this paper reports a novel composite tendon and pneumatic hybrid-driven tapered soft manipulator that mimics the multi-muscle action of the elephant trunk. In the design, a common Bowden tube is introduced as an artificial tendon to simulate the thrust of elephant trunk muscles. This paper first establishes an equivalent finite element model for Bowden tube tendons, along with an exploration of the impact of constraint ring distribution intervals on tendon buckling during thrust generation. This paper also establishes a finite element model for the entire experimental prototype, validating the effectiveness of Bowden tendon tension and thrust and demonstrating the large deformation curvature and flexible motion space of the soft manipulator. Finally, the paper experimentally tests the stability of repetitive motion, load-bearing capacity, and safety of active softening contact with humans of the soft manipulator, demonstrating that this biomimetic design exhibits not only flexibility and agility but also robustness in motion and precision in accuracy, closely resembling the capabilities of an elephant trunk, and holds promise as flexible supernumerary robotic limbs for mobile or humanoid robots. © 2024, The Authors. All rights reserved.

关键词： Tendons

Collaborative Fall Detection and Response Using Wi-Fi Sensing and Mobile Companion Robot

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Collaborative Fall Detection and Response Using Wi-Fi Sensin...

IEEE International Conference on Robotics and Biomimetics

作者： Yunwang Chen Yaozhong Kang Ziqi Zhao Yue Hong Lingxiao Meng Max Q.-H. Meng Shenzhen Key Laboratory of Robotics Perception and Intelligence Southern University of Science and Technology Shenzhen China Department of Electrical and Electronic Engineering SUSTech Shenzhen China School of System Design and Intelligent Manufacturing SUSTech Shenzhen China

ISBN: (数字)9798331509644

ISBN: (纸本)9798331509651

This paper presents a collaborative fall detection and response system integrating Wi-Fi sensing with robotic assistance. The proposed system leverages channel state information (CSI) disruptions caused by movements to detect falls in non-line-of-sight (NLOS) scenarios, offering non-intrusive monitoring. Besides, a companion robot is utilized to provide assistance capabilities to navigate and respond to incidents autonomously, improving efficiency in providing assistance in various environments. The experimental results demonstrate the effectiveness of the proposed system in detecting falls and responding effectively.

关键词： Navigation Biomimetics Collaboration Robot sensing systems Sensors Fall detection Wireless fidelity Monitoring Injuries Channel state information

Super-Twisting Control for Re-entry Rigid-Elastic Coupled Hypersonic Vehicles

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Super-Twisting Control for Re-entry Rigid-Elastic Coupled Hy...

Chinese Automation Congress (CAC)

作者： Wentao Tang Junfang Fan Yi Ji Yafeng Li Xiaobin Xu Luyao Zang Beijing Key Laboratory of High Dynamic Navigation Technology Beijing Information Science and Technology University Beijing China School of Automation Beijing Information Science and Technology University Beijing China The System Design Institute of Mechan-ical-Electrical Engineering Beijing China

A super-twisting control strategy is proposed to tackle the complex problem of attitude stabilization control for rigid-elastic coupled hypersonic vehicles experiencing significant aerodynamic perturbations. Initially, the elastic modes are treated as uncertain factors, leading to the construction of a control-oriented dynamic model. To design the attitude subsystem, a combination of a super-twisting algorithm and a non-singular terminal sliding mode is proposed. A first-order differentiator is introduced to address the “derivative explosion” issue commonly found in traditional control methods, thus eliminating the need for intricate differential computations. Moreover, a switching control strategy is integrated into the nonlinear feedback control law design, ensuring robust velocity tracking. Simulation results validate that the proposed control method surpasses conventional methods in both tracking performance and robustness.

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Capillary Evaporating Film Model for a Screen-Wick Heat Pipe

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SSRN 2022年

作者： Ma, Yugao Zhang, Yingnan Yu, Hongxing Huang, Shanfang Deng, Jian Chai, Xiaoming Zeng, Chang Zhang, Zhuohua He, Xiaoqiang Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Department of Engineering Physics Tsinghua University Beijing100084 China

Screen-wick heat pipes are efficient passive heat transfer devices. The heat transfer capacity is determined by the capillary pressure, which is related to the film curvature inside the screen wick. A capillary evaporating film model was developed for the screen wick that divided the film into a capillary pressure microlayer region and a macroscopic film. The film surface shape in the capillary pressure microlayer region is mainly influenced by the long-range molecular forces (disjoining pressure) and the surface tension, while the film surface shape in the macroscopic film is affected by the wick geometry. The numerical results show that the present model more accurately predicts the three-dimensional characteristics of the liquid film inside the screen wick than the classical model. The wire opening distance and the wire diameter affect the capillary pressure and the flow path in the wick. As the liquid film recedes into the wick, the capillary force first increases and then decreases. The film dynamics in the wick are related to the liquid height, which automatically adapts to the required evaporation and pressure balance for a given heat load. High operating temperatures can lead to a mismatch between the capillary head and the pressure loss, leading to dry out in the wick. Thus, this work provides a reference for operating alkali-metal wick heat pipes. © 2022, The Authors. All rights reserved.

关键词： Heat pipes

Perceived vs. Objective Human Performance in Diagnostic Tasks: Under-Confidence or Over-Confidence?

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SSRN 2022年

作者： Lyu, Xi Li, Zhizhong Ma, Quan She, Manrong Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China Department of Industrial Engineering Tsinghua University Beijing100084 China

Humans are not very good at assessing their own performance, and usually exhibit over-confidence. Little effort has been done to investigate how and how well diagnosticians perceive their performance of sub-processes of diagnosis, for example information seeking and information integration. This study analyzed the performance data of an experiment of diagnosing an accident in a simulated nuclear power plant. The objective performance was measured by eight indicators and the perceived performance was measured by three indicators. Difference relations and correlations between these indictors were explored. Results showed that on one hand there were systematic deviations between perceived and objective performance, on the other hand the perceptions did have some validity. Perceptions of information seeking manifested under-confidence while perceptions of information integration and the overall diagnosis manifested over-confidence. The authors argue that these two biases were mutually complementary and facilitating rather than contradictory. The findings could be used to help diagnosis-related training, operation and decision making. © 2022, The Authors. All rights reserved.

关键词： Information retrieval

Effects of rolling on characteristics of system under forced circulation and natural circulation

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Effects of rolling on characteristics of system under forced...

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

作者： Cai, Rong Yue, Nina Fang, Hongyu Chen, Baowen Liu, Lili Ma, Zehua Science and Technology on Reactor System Design Technology Laboratory Chengdu China Cnnc Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology Chengdu China Xi'an Jiaotong University Xi'an Shaanxi China

ISBN: (纸本)9780791883785

The marine nuclear power plant operating in the marine environment has complicated motion under the influence of wind and waves. The movement of marine nuclear power plant will affect the thermal-hydraulic characteristics of its nuclear reactor system. Compared with other typical motion conditions, the effects of rolling conditions on the thermal-hydraulic characteristics of the nuclear reactor system are the most complex. In order to study the effects of rolling conditions on the thermal-hydraulic characteristics of the nuclear reactor system, a thermal-hydraulic system code for motion conditions named STAC was developed. The STAC code was verified by the experiments conducted in Japan. The effects of rolling conditions on the thermal-hydraulic characteristics of the nuclear reactor system under forced circulation and natural circulation are studied with the STAC code. The simulation results show that the thermal parameters of the reactor system under rolling condition fluctuate periodically. The fluctuation period of the thermal parameters of the core is half of the rolling period, and the fluctuation periods of other thermal parameters are the same as the rolling period. The effect of rolling condition on thermalhydraulic parameters under forced circulation is smaller than that under natural circulation. The fluctuation amplitudes of the thermal parameters increase with the angle amplitude of the rolling condition. There is a rolling period with the smallest fluctuation amplitude. Under the rolling condition with short period, the fluctuation amplitudes of the thermal parameters increase and their average values change rapidly as the rolling period decreases. Under the rolling condition with large period, the fluctuation amplitudes of the thermal parameters increase with the rolling period, and they tend to fixed values. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Nuclear fuels

Anomaly Detection of Logistics Packages Based on CNN and Image Recognition technology

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Anomaly Detection of Logistics Packages Based on CNN and Ima...

Data science and Computer Application (ICDSCA), IEEE International Conference on

作者： Kun Liang Hang Zhang School of Management Tianjin University of Technology Tianjin China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin China

ISBN: (数字)9798350368239

ISBN: (纸本)9798350368246

To address abnormal situations such as packaging damage, liquid leakage, and item displacement during logistics package transportation, this paper introduces Convolutional Neural Network (CNN) and image recognition technology to achieve real-time anomaly detection and alarm, improving the response speed and accuracy of the logistics system. First, by designing multiple layers of convolution and pooling layers, adding Batch Normalization layers and Dropout layers to prevent overfitting, a CNN deep learning model suitable for logistics package anomaly detection is constructed. key features are extracted through image preprocessing methods such as normalization and data enhancement to ensure that the model has high recognition adaptability to various abnormal situations such as damage and leakage. Secondly, through data enhancement methods such as rotation, scaling, brightness adjustment, and transfer learning using pre-trained models, the model's adaptability in different lighting, angles, and occlusion conditions is improved. Finally, the model is applied to actual monitoring, and real-time alarms are issued for abnormalities such as damage and leakage, which are then fed back to the system closed-loop management. This method is significantly better than traditional methods in terms of detection accuracy and response speed. Under natural light environment, the model detection accuracy is as high as 98.4%, reducing false positives and false negatives. Combining CNN's anomaly detection technology effectively improves the accuracy and efficiency of logistics monitoring and provides technical support for intelligent logistics management.

关键词： Industries Adaptation models Accuracy Image recognition Data models Real-time systems Convolutional neural networks Anomaly detection Monitoring Logistics