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SSRN 2022年

作者： Zhao, Jiajun Sun, Dan Wang, Yuanyuan Xi, Liu Chen, Ping Zhao, Jijun Dalian University of Technology Liaoning Dalian China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Sichuan Chengdu China

Extensive attention has been paid to accident tolerant fuels (ATFs), such as uranium mononitride (UN) and uranium sesquisilicide (U3Si2), which are regarded as the potential candidates to replace uranium dioxide (UO2) in light water reactor (LWR). However, the thermodynamic behavior of fission gas atom in these fuels that can quantitatively affect the burnup characteristics of ATF needs to be explored. To this end, the systematic ab initio investigation on the energetic properties of xenon (Xe)-vacancy complexes in UO2, UN and U3Si2 is performed with the GGA+U approach as well as the corrected chemical potential. The stabilities of Xe-vacancy clusters, including interstitial trap site (IS), mono-, bi- and tri-atomic vacancy, are thoroughly assessed. The formation energies of vacancy complexes indicate that it is more likely to form vacancy cluster defects and their complexes with Xe in UO2 and to generate mono-atomic vacancy and Xe-vacancy complex in both UN and U3Si2. Xe can be strictly confined by the trap sites in UO2 and UN, and yet in U3Si2, it prefers to move to the centre of a large free volume trap site. The strongest soluble characteristic of Xe in U3Si2 indicates excellent storage compacity of fission gas products in the matrix. This work can provide comprehensive insights into the original reason of interplay between Xe and vacancy as well as the thermodynamic behavior of those defects in the uranium-based fuels. © 2022, The Authors. All rights reserved.

关键词： Uranium dioxide

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Load Calculation of Cylinder Moving in Waves 34th

Load Calculation of Cylinder Moving in Waves

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34th International Ocean and Polar Engineering Conference, ISOPE 2024

作者： Li, Jing Wang, Junyi Wang, Xianzhou Wang, Qing School of Naval Architecture and Ocean Engineering Huazhong University of Science and Technology China Key Laboratory of ship and ocean hydrodynamics of Hubei Province Hubei Wuhan China Wuhan Second Ship Design and Research Institute Hubei Wuhan China

ISBN: (纸本)9781880653784

In order to investigate the wave load of cylinder such as masts on submarines, this study compares numerical simulations of cylinder under different submerged depths and speeds in irregular wave and calm water. Before the study, validation of the numerical method was conducted for time-steps/grid independent studies and uncertainty analysis of the numerical simulation results includes evaluation of significant wave height. Then, the numerical loads in wave conditions are compared with those in calm waters, and the numerical wave results are also compared with those calculated by Morison formula. Finally, the discipline of wave load under different conditions and the ratios of numerical results to Morison formula results are concluded. © 2024 by the International Society of Offshore and Polar Engineers (ISOPE).

关键词： Uncertainty analysis

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A high-resolution numerical investigation of unsteady wake vortices for coaxial rotors in hover

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Chinese Journal of Aeronautics 2024年第11期37卷 278-299页

作者： Shaoqiang HAN Wenping SONG Zhonghua HAN Jianhua XU Tianfu Engineering-oriented Numerical&Software Innovation Center College of Computer ScienceSichuan UniversityChengdu 610065China National Key Laboratory of Science and Technology on Aerodynamic Design and Research School of AeronauticsNorthwestern Polytechnical UniversityXi’an 710072China

High-resolution numerical simulations for wake vortical flows have long been a challenge in rotor aerodynamics.A novel spectrum-optimized sixth-order Weighted Essentially NonOscillatory(WENO)scheme is proposed to discretize inviscid fluxes on moving overset grids,and the Improved Delayed Detached Eddy Simulation(IDDES)is employed to resolve turbulent *** integration of these methods facilitates a comprehensive numerical investigation into the unsteady vortical flows over coaxial rotors in *** results highlight the substantial improvement in numerical resolution,in terms of both spatial structure and temporal evolution of unsteady multiscale wake *** rotors in hover manifest three primary scales of wake vortex structures:(A)the helical evolution of primary blade tip vortices and the periodic occurrence of strong Blade-Vortex Interactions(BVI);(B)the continuous shedding of small-scale horseshoeshaped vortices from the trailing edges of rotor blades,forming the vortex sheets;(C)the emergence of small-scale secondary vortex braids induced by interactions between rotor tip vortices and the vortex *** vortex structures and their interactions cause high-frequency oscillations in rotor disk loads and induce unsteady perturbations in the local flow *** among these primary vortices,coupled with the generation of secondary vortices,result in the dissipation,distortion,and breakup of the rotor tip vortices,ultimately forming a vortex ***,a substantial quantity of seemingly weak small-scale secondary vortex braids significantly contribute to energy dissipation during the evolution of wake vortices for coaxial rotors in hover.ó2024 Chinese Society of Aeronautics and *** and hosting by Elsevier *** is an open access article under the CC BY-NC-ND license(http://***/licenses/by-nc-nd/4.0/).

关键词： Coaxial rotor Blade tip vortex Secondary vortex High-order scheme IDDES Moving overset grid

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Neural Oscillation-dependent Electroencephalographic Microstates Reveal Emotional Process-specific Dynamic Neuromarkers of Depression

Neural Oscillation-dependent Electroencephalographic Microst...

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2024 IEEE International Conference on Bioinformatics and Biomedicine, BIBM 2024

作者： Cui, Kunbo Zhao, Mingqi Wu, Zhongqing Zhang, Lixin Jiang, Hua Zhao, Qinglin Hu, Bin Lanzhou University School of Information Science and Engineering Lanzhou China Lanzhou University Key Laboratory of Special Functional Materials and Structural Design Ministry of Education Lanzhou China Beijing Institute of Technology School of Medical Technolog Beijing China

ISBN: (纸本)9798350386226

Depressive affective dysfunction could be manifested by dynamic reorganization processes of functional brain networks under emotional tasks. However, such emotional task-specific reorganizations remain not fully understood in terms of spatiotemporal organization of oscillation dynamics. The insufficiency of approaches for quantifying such dynamic reorganization limits the effective extraction of dynamic neuromarkers of depressive affective dysfunction. To address this gap, this study presents a neural oscillation-dependent microstate approach to quantify the dynamic reorganization process of functional networks at high temporal resolution. The approach was tested by analyzing a 64-channel electroencephalography (EEG) dataset with 110 participants (55 depressed patients and 55 normal controls) collected during emotional tasks with four affective polarities (positive, neutral, negative, and resting state). Our analyses revealed oscillation-dependent microstates that reflected abnormalities in the networks associated with external information processing and interoception in depression. Our analyses further suggest that such abnormalities may be caused by dysfunction in a limited number of brain regions, which then dynamically affects functional brain networks. These findings may reflect increased self-focus and deficits in the perception of external information in depression. In summary, our study further explores source-level evidence related to abnormalities in microstate features of depression based on the generalization of depression microstate research to a multi-band framework. Our study provides a direction for expanding the application of dynamic reorganization analyses of functional networks with high temporal resolution, and provides new support and insights into the neural mechanisms of affective dysfunction in depression. © 2024 IEEE.

关键词： Electroencephalography

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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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Larger Recovery Strain in a Conisi Alloy Due to Enhanced Reversibility of FccHcp Martensitic Transformation

SSRN

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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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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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Theoretical research on two-phase flow instability in parallel rectangular channels under periodic perturbation

Theoretical research on two-phase flow instability in parall...

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

作者： Qian, Libo Deng, Jian Huang, Tao Cai, Rong Science and Technology on Reactor System Design Technology Laboratory Npic Chengdu Sichuan China

ISBN: (纸本)9780791883785

A theoretical model for Density Wave Oscillations (DWOs) flow instability in parallel rectangular channels under periodic heaving motion is established with a lumped mathematical model based on homogenous hypothesis. The parallel rectangular channels comprise of the entrance section, the heating section, the riser section and the upper- and lower plenums, which guarantee the isobaric pressure drop condition between channels and the model consists of boiling channel model, pressure drop model, parallel channel model, additional pressure drop model generated by heaving motions, the constitutive and numerical models. The effect of periodic perturbation is introduced through additional pressure drop in the momentum equation. The model is validated with experimental data of a twin-rectangular-channel flow instability experiment under static condition. Then the flow instability in parallel-rectangular-channel system is studied under periodic perturbation and the margin of flow instability and the threshold power of the system under static condition is calculated as basis condition for comparison. The effect of the amplitude and period of perturbation is analyzed analytically and the results show that the amplitude and period of perturbation shows little effect on flow instability. While when the additional pressure difference introduced by heaving motion is comparable with that under static condition, the effect of amplitude becomes stronger. And the period of perturbation strongly effects the threshold power when it is identical to that of natural period of the system, which can be explained by resonance between the perturbation and the system. And this effect is even stronger when the asymmetric heating condition is introduced. © 2020 American Society of Mechanical Engineers (ASME). All rights reserved.

关键词： Pressure drop

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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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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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