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Atomic study of hydrogen behaviors at∑3(111)grain boundary in equiatomic CoCrNi and CoCrNiFe alloys

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Tungsten 2022年第3期4卷 239-247页

作者： Hua-Qing Guan Yan-Mei Jing shao-song huang Key Laboratory of Material Modification by Laser Ion and Electron Beams(Dalian University of Technology)Ministry of EducationDalian116024China

High-entropy alloys are potential advanced structural materials for applications in nuclear energy due to their proved high irradiation ***,exposing components made of structure materials to service conditions under certain nuclear environments may induce hydrogen embrittlement(HE)as one of the typical failure *** this work,we performed density functional theory(DFT)calculations to examine the role of specific element species in HE mechanism in CoCrNi and CoCrNiFe *** solution energy,binding energy and diffusion barrier of H atoms at∑3 GBs(GBs is short for grain boundaries)are *** on the DFT data,we found that Cr limits the H atom to a specific potential position,thus suppresses H *** dipole moment interaction between H and Fe atoms weakens the binding of H *** lattice distortion effect-induced trapping for H provides higher H diffusion barriers at∑3 GBs than that in pure Ni.

关键词： Hydrogen embrittlement Grain boundary DFT High-entropy alloy

Identification of Linear Systems Using Binary Sensors with Random Thresholds

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Journal of Systems Science & Complexity 2024年第3期37卷 907-923页

作者： huang Zhiyong song Qijiang School of Mathematics Renmin University of ChinaBeijing 100872China School of Mathematics Sino-French InstituteRenmin University of ChinaBeijing 100872China

In this paper,the problem of identifying autoregressive-moving-average systems under random threshold binary-valued output measurements is *** the help of stochastic approximation algorithms with expanding truncations,the authors give the recursive estimates for the parameters of both the linear system and the binary *** reasonable conditions,all constructed estimates are proved to be convergent to the true values with probability one,and the convergence rates are also established.A simulation example is provided to justify the theoretical results.

关键词： α-mixing binary sensor quantized system stochastic approximation stochastic thresh-old strongly consistent system identification

Irradiation-induced void evolution in iron：A phase-field approach with atomistic derived parameters

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Chinese Physics B 2017年第2期26卷 363-369页

作者： Yuan-Yuan Wang Jian-Hua Ding Wen-Bo Liu shao-song huang Xiao-Qin Ke Yun-Zhi Wang Chi Zhang Ji-Jun Zhao Key Laboratory of Materials Modification by Laser Ion and Electron Beams (Ministry of Education) Dalian University of Technology Dalian 116024 China Department of Nuclear Science and Technology Xi' an Jiaotong University Xi' an 710049 China Center of Microstructure Science Multi-Disciplinary Materials Research Center Frontier Institute of Science and TechnologyState Key Laboratory for Mechanical Behavior of Materials Xi' an Jiaotong University Xi' an 710049 China Department of Materials Science and Engineering Ohio State University Columbus Ohio 43210 USA Key Laboratory of Advanced Materials of Ministry of Education School of Materials Science and Engineering Tsinghua University Beijing 100084 China

A series of material parameters are derived from atomistic simulations and implemented into a phase field（PF） model to simulate void evolution in body-centered cubic（bcc） iron subjected to different irradiation doses at different *** simulation results show good agreement with experimental observations — the porosity as a function of temperature varies in a bell-shaped manner and the void density monotonically decreases with increasing temperatures; both porosity and void density increase with increasing irradiation dose at the same temperature. Analysis reveals that the evolution of void number and size is determined by the interplay among the production, diffusion and recombination of vacancy and interstitial.

关键词： phase field method atomistic simulation void evolution irradiation

Comparison-embedded evidence-CNN model for fuzzy assessment of wear severity using multi-dimensional surface images

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Friction 2024年第6期12卷 1098-1118页

作者： Tao shao Shuo WANG Qinghua WANG Tonghai WU Zhifu huang Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

Wear topography is a significant indicator of tribological behavior for the inspection of machine health *** intelligent in-suit wear assessment method for random topography is here ***-dimension(3D)topography is employed to address the uncertainties in wear ***,3D topography reconstruction from a worn surface is accomplished with photometric stereo vision(PSV).Then,the wear features are identified by a contrastive learning-based extraction network(WSFE-Net)including the relative and temporal prior knowledge of wear ***,the typical wear degrees including mild,moderate,and severe are evaluated by a wear severity assessment network(WSA-Net)for the probability and its associated uncertainty based on subjective *** integrating the evidence information from 2D and 3D-damage surfaces with Dempster–Shafer(D–S)evidence,the uncertainty of severity assessment results is further *** proposed model could constrain the uncertainty below 0.066 in the wear degree evaluation of a continuous wear experiment,which reflects the high credibility of the evaluation result.

关键词： wear severity assessment contrastive learning subjective logic Dempster-Shafer(D-S)evidence theory

A learning-based control pipeline for generic motor skills for quadruped robots

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 443-454页

作者： Yecheng shao Yongbin JIN Zhilong huang Hongtao WANG Wei YANG Center for X-Mechanics Zhejiang UniversityHangzhou310027China ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou311200China State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou310058China Institute of Applied Mechanics Zhejiang UniversityHangzhou310027China

Performing diverse motor skills with a universal controller has been a longstanding challenge for legged *** motion imitation-based reinforcement learning(RL)has shown remarkable performance in reproducing designed motor skills,the trained controller is only suitable for one specific type of *** synthesis has been well developed to generate a variety of different motions for character animation,but those motions only contain kinematic information and cannot be used for *** this study,we introduce a control pipeline combining motion synthesis and motion imitation-based RL for generic motor *** design an animation state machine to synthesize motion from various sources and feed the generated kinematic reference trajectory to the RL controller as part of the *** the proposed method,we show that a single policy is able to learn various motor skills ***,we notice the ability of the policy to uncover the correlations lurking behind the reference motions to improve control *** analyze this ability based on the predictability of the reference trajectory and use the quantified measurements to optimize the design of the *** demonstrate the effectiveness of our method,we deploy the trained policy on hardware and,with a single control policy,the quadruped robot can perform various learned skills,including automatic gait transitions,high kick,and forward jump.

关键词： Quadruped robot Reinforcement learning(RL) Motion synthesis Control

Stationary Almost Markov ε-Equilibria for Discounted Stochastic Games with Borel Spaces and Unbounded Payoffs

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Journal of Systems Science & Complexity 2024年第4期37卷 1672-1684页

作者： WU Yiting ZHANG Junyu huang song School of Mathematics Sun Yat-Sen UniversityGuangzhou 510275China School of Software and Microelectronics Peking UniversityBeijing 100871China

This paper is concerned with nonzero-sum discrete-time stochastic games in Borel state and action spaces under the expected discounted payoff *** payoff function can be *** transition probability is a convex combination of finite probability measures that are dominated by a probability measure on the state space and depend on the state *** suitable conditions,the authors establish the existence of stationary almost Markov ε-equilibria and give an approximation method via some stochastic games with bounded ***,a production game is introduced to illustrate the applications of the main result,which generalizes the bounded payoff case.

关键词： Almost Markovε-equilibrium Borel state space expected discounted payoff criterion nonzero-sum stochastic games unbounded payoffs

Noninvasive beam diagnosis based on the TM_(010)mode

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Nuclear Science and Techniques 2024年第7期35卷 115-125页

作者： Chuang-Ye song Wen-Hui huang Department of Engineering Physics Tsinghua University BeijingBeijing100084China of Education Beijing100084China

A resonant cavity based on the TM_(010)mode is an effective tool for noninvasive beam characterization. This technique has the advantages of a high signal-to-noise ratio, compact structure, and is related to multiple parameters compared with other beam monitors. In this study, high-precision measurements of the bunch charge, arrival time, bunch length, and energy parameters based on the TM_(010)mode are discussed. A cavity beam arrival time monitor(BAM) utilizing a phase cavity has been widely used in many facilities. Regarding bunch-length measurements, the influence of the beam energy, beam offset,and longitudinal spectrum on the TM_(010)mode are carefully considered to reduce errors, and the theoretical resolution of two cavities with different frequencies is analyzed. Owing to the dependence of the beam velocity of the beam loss factor, this method can also be used for the detection low beam energy using two cavities with the same frequency but different cavity lengths. A set of three cavities with different lengths and frequencies of 1.902 and 11.424 GHz is presented for measuring the four aforementioned parameters.

关键词： TM_(010)mode Noninvasive diagnosis Beam length Low energy

Patterns and drivers of seasonal water sources for artificial sand-fixing plants in the northeastern Mu Us sandy land,Northwest China

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Pedosphere 2024年第1期34卷 63-77页

作者： Yanwu PEI Laiming huang Ming'an shao Jiao WANG Yinglong ZHANG Yellow River Delta Modern Agricultural Engineering Laboratory Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Natural Resources and Environment Northwest Agriculture and Forestry UniversityYangling 712100China State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences of Chinese Academy of SciencesBeijing 100085China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Shenmu Ecological Association Shenmu 719399China

Understanding plant water-use patterns is important for improving water-use efficiency and for sustainable vegetation restoration in arid and semi-arid regions. However, seasonal variations in water sources and their control by different sand-fixing plants in water-limited desert ecosystems remain poorly understood. In this study, stable isotopic ratios of hydrogen(δ^(2)H) and oxygen(δ^(18)O) in precipitation, soil water, groundwater, and xylem water were determined to document seasonal changes in water uptake by three representative plant species(Pinus sylvestris var. mongolica Litv., Amygdalus pedunculata Pall., and Salix psammophila) in the northeastern Mu Us sandy land, Northwest China. Based on the depth distribution and temporal variation of measured gravimetric soil water content(SWC), the soil water profile of the three species stands was divided into active(0.01 g g^(-1)45%) layers. Annually, P. sylvestris, A. pedunculata, and S. psammophila obtained most water from deep(59.2%±9.7%, moist layer and groundwater),intermediate(57.4%±9.8%, stable and moist layers), and shallow(54.4%±10.5%, active and stable layers) sources, respectively. Seasonally, the three plant species absorbed more than 60% of their total water uptake from the moist layer and groundwater in the early(June) dry season;then, they switched to the active and stable layers in the rainy season(July–September) for water resources(50.1%–62.5%). In the late(October–November) dry season, P. sylvestris(54.5%–66.2%) and A. pedunculata(52.9%–63.6%) mainly used water from stable and moist layers, whereas S. psammophila(52.6%–70.7%) still extracted water predominantly from active and stable layers. Variations in the soil water profile induced by seasonal fluctuations in precipitation and groundwater levels and discrepancies in plant pheno

关键词： desert ecosystem MixSIAR model plant water uptake soil moisture stable isotopes vegetation restoration water-use efficiency

Effect of Low-Temperature Thermal Oxidation on the Capillary Performance of Sintered Copper Powder Wicks

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Journal of Thermal Science 2024年第1期33卷 29-40页

作者： ZHU Minghan FANG Runquan HU Yanxin ZHANG Jiangyun shao Dan huang Jin School of Material and Energy Guangdong University of TechnologyGuangzhou 510006China School of Electric Power Engineering Guangdong Polytechnic of Water Resources and Electric EngineeringGuangzhou 510006China Research into Artifacts Guangdong Key Laboratory of Battery SafetyGuangzhou Institute of Energy testingGuangzhou 511447China

In this study,a composite powder capillary wick is prepared,manufactured by sintering copper powder and surface treated by low-temperature thermal *** is used to improve the performance of the capillary *** forced flow method and infrared imaging method are used to test the permeability and capillary performance of the *** effects of different oxidation temperatures on the performance of capillary wick are *** experimental results show that the wetting performance of the oxidized samples is significantly *** the increase of oxidation temperature,the permeability *** capillary height and velocity of the thermally oxidized samples are significantly higher than those of the untreated capillary ***,the oxidation temperature needs to be adjusted to obtain the best capillary *** highest capillary performance is found at oxidation temperature of 300℃,with an increase of 46% compared to the untreated *** with other composite wicks show that the sample with an oxidation temperature of 300℃ has competitive capillary performance,making it a favorable alternative to two-phase heat transfer *** study shows that combining low-temperature thermal oxidation technology with powder sintering is a convenient and effective method to improve the capillary performance of powder wicks.

关键词： low-temperature thermal oxidation capillary performance copper powder permeability