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Effect of temperature on the mechanical properties of Ni-based superalloys via molecular dynamics and crystal plasticity

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Journal of Materials science & technology 2024年第36期203卷 126-142页

作者： Y.-Z.Liu Z.-L.Shi Y.-B.Zhang M.Qin S.-P.Hu X.-G.Song W.Fu B.-J.Lee State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066000China Department of Materials Science and Engineering National University of SingaporeSingapore 117576Singapore Shandong Institute of Shipbuilding Technology Weihai 264209China Department of Materials Science and Engineering Pohang University of Science and TechnologyPohang 790784Korea

Study on the influence of temperature on the mechanical properties across multiple scales has been a focus on the research of Hastelloy-X(HX)alloys for the application in high-temperature structure *** this work,Molecular Dynamics(MD)and Crystal Plasticity(CP)are put together to solve it from atomic scale to mesoscopic *** research indicates that the deformation of HX alloy occurs in two stages at temperature below 300 K:initially,as stacking fault deforms,stacking fault can trans-form into twinning with increasing *** the temperature exceeds 300 K,deformation primarily forms a stacking *** twinning deformation path transforms from intrinsic stacking fault to extrin-sic stacking fault and then to twinning.A mesoscopic-scale CP model was developed using atomic-scale deformation mechanisms to bridge the gap between deformation mechanisms and experimental *** CP results indicate a functional relationship between the strength of HX alloy and *** relationship appears insensitive to crystal texture and grain *** grain morphology and texture into the model significantly impacts the strength response of calculating HX *** the ten-sile deformation of HX alloy at 300 and 1173 K,the atomic scale deformation results characterized by transmission electron microscopy are aligned with the MD simulation *** relationship between strength and temperature predicted by CP results has also been validated.A thorough investigation into the deformation behavior of HX alloys across different scales,employing MD and CP models,introduces a novel approach for predicting the mechanical properties of superalloys.

关键词： Molecular dynamics Twinning Superalloy High-temperature strength Crystal plasticity

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Spacecraft Chase and Escape Game Based on PPO Algorithm 7th

Spacecraft Chase and Escape Game Based on PPO Algorithm

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7th Chinese Conference on Swarm Intelligence and Cooperative control, CCSICC 2023

作者： Ye, Ruiqing Deng, Wudong Guo, Yanning Li, Chuanjiang Department of Control Science and Engineering School of Astronautics Harbin Institute of Technology Harbin150001 China Shanghai Institute of Satellite Engineering Shanghai201109 China

ISBN: (纸本)9789819733231

This paper addresses the pursuit-evasion game problem for spacecraft using pulse propulsion, uses Particle Swarm Optimization (PSO) and Proximal Policy Optimization (PPO) algorithms as pursuit and evasion strategies for the spacecraft. The distance between the spacecraft is employed as the optimization objective for the PSO algorithm, aiming to minimize the distance between them. Similarly, the distance between the spacecraft is used as the reward function for the PPO algorithm, aiming to maximize the distance between them. Additionally, the paper takes into account that the spacecraft use pulse propulsion with a maximum velocity increment constraint. Through simulation examples, the effectiveness of using the PPO algorithm as a spacecraft strategy-solving method is validated. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Spacecraft

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Attitude and Orbit Optimal control of Combined Spacecraft via a Fully-Actuated System Approach

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Journal of Systems science & Complexity 2022年第2期35卷 623-640页

作者： DUAN Guangquan LIU Guo-Ping Center for Control Theory and Guidance Technology Harbin Institute of TechnologyHarbin 150001China Department of Electronic and Electrical Engineering Southern University of Science and TechnologyShenzhen 518055China

This paper investigates the attitude and orbit control for the combined spacecraft formed after a target spacecraft without the autonomous control ability is captured by a service *** optimal controller of fully-actuated system is proposed to realize the attitude and orbit stabilization control of combined *** stability of the system is proved by introducing Lyapunov *** simulation of the combined spacecraft and physical experiment based on the combined spacecraft simulator(CSS)are *** simulation and experiment results demonstrate the effectiveness and practicability of the optimal controller of fully-actuated system.

关键词： Attitude control combined spacecraft fully-actuated system optimal controller orbit control

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Boosting the direct conversion of NH4HCO3 electrolyte to syngas on Ag/Zn zeolitic imidazolate framework derived nitrogen-carbon skeleton

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Frontiers of Chemical science and engineering 2023年第9期17卷 1196-1207页

作者： Huiyi Li Jianmin Gao Jingjing Shan Qian Du Yu Zhang Xin Guo Shaohua Wu Zhijiang Wang Institute of Combustion Engineering School of Energy Science and EngineeringHarbin Institute of TechnologyHarbin150001China MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin150001China Harbin Bolier Co. Ltd.Harbin150040China Department of Environmental Engineering Shanxi UniversityTaiyuan030006China

The electrochemical reduction of NH4HCO3 to syngas can bypass the high energy consumption of high-purity CO_(2)release and compression after the ammonia-based CO_(2)capture *** technology has broad prospects in industrial applications and carbon neutrality.A zeolitic imidazolate framework-8 precursor was introduced with different Ag contents via colloid chemical *** material was carbonized at 1000℃to obtain AgZn zeolitic imidazolate framework derived nitrogen carbon catalysts,which were used for the first time for boosting the direct conversion of NH4HCO3 electrolyte to *** AgZn zeolitic imidazolate framework derived nitrogen carbon catalyst with a Ag/Zn ratio of 0.5:1 achieved the highest CO Faradaic efficiency of 52.0%with a current density of 1.15 mA·cm^(−2)at−0.5 V,a H2/CO ratio of 1-2(−0.5 to−0.7 V),and a stable catalytic activity of more than 6 *** activity is comparable to that of the CO_(2)-saturated NH4HCO3 *** highly discrete Ag-N_(x)and Zn-N_(x)nodes may have combined catalytic effects in the catalysts synthesized by appropriate Ag doping and sufficient *** nodes could increase active sites of catalysts,which is conducive to the transport and adsorption of reactant CO_(2)and the stability of*COOH intermediate,thus can improve the selectivity and catalytic activity of CO.

关键词： Ag catalyst zeolitic imidazolate framework CO_(2)electroreduction ammonium bicarbonate electrolyte syngas

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Mechanical and shape-memory properties of TPMS with hybrid configurations and materials

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International Journal of Smart and Nano Materials 2024年第4期15卷 786-810页

作者： Tianzhen Liu Wei Zhao Yongtao Yao Cheng Lin Hanxing Zhao Jianguo Cai Key Laboratory of C&PC Structures of Ministry of Education National Prestress Engineering Research CenterSoutheast UniversityNanjingChina Department of Astronautical Science and Mechanics Harbin Institute of TechnologyHarbinChina National Key Laboratory of Science and Technology on Advanced Composites in Special Environments Harbin Institute of TechnologyHarbinChina

Triply periodic minimal surface(TPMS)structures with excellent properties of stable energy absorption,light weight,and high specific strength could potentially spark immense interest for novel and programmable functions by combining smart materials,*** memory polymers(SMPs).This work proposes TPMS lattices with hybrid configurations and materials that are composed of viscoelastic and shape-memory materials with the aim to bring temperature-dependent mechanical properties and additional dissipation *** configurations and diverse materials of polylactic acid(PLA),fiber-reinforced PLA,and polydimethylsiloxane(PDMS)are induced,generating five types of TPMS lattices,including(Schoen’s I-WP)IWP uniform lattice,IWP lattice with density gradient,hybrid configurations,hybrid materials,and filled PDMS,which are fabricated by 3D *** fracture morphologies and the distribution of carbon fibers are demonstrated via scanning electron microscopy with a focus on the influence of carbon fiber on shape-memory and mechanical *** recovery tests are conducted,which proves good shape memory properties and reusable capability of TPMS *** combined methods of experiments and numerical simulation are adopted to evaluate mechanical properties,which presents multi-stage energy absorption ability and tunable vibration isolation performances associated with temperature and hybridization *** work can promote extensive research and provide substantial opportunities for TPMS lattices in the development of functional applications.

关键词： Triply periodic minimal surface shape memory property hybridization multi-stage energy absorption

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Adaptive RBFNN-Based Fast Fixed-Time Backstepping control for Robotic Manipulators

Adaptive RBFNN-Based Fast Fixed-Time Backstepping Control fo...

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2024 China Automation Congress, CAC 2024

作者： Yao, Bowei Liu, Zhuang Zhu, Qiaoman Zhang, Ouyang Chen, Weiliang Liu, Jianxing Control Science and Engineering Harbin Institute of Technology Harbin China Jianghuai Advance Technology Center Hefei China

ISBN: (纸本)9798350368604

This article explores the time-varying trajectory tracking control for robotic manipulators with uncertainties. Initially, we propose a novel fixed-time backstepping control algorithm. This innovation allows the system to achieve fixed-time convergence more rapidly. Considering that the manipulator system are affected by disturbance and model uncertainty, we adopt an adaptive radial basis function neural network (RBFNN) to compensate for the lumped disturbance. The effectiveness of the proposed algorithm is verified by simulation. Compared to existing methods, this approach shows a more rapid convergence rate and superior convergence performance. © 2024 IEEE.

关键词： Radial basis function networks

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A deep learning-based model for automated STN localization using local field potentials in Parkinson’s disease

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Soft Computing 2025年第4期29卷 2343-2362页

作者： Hosny, Mohamed Naeem, Mohamed A. Zhu, Minwei Gao, Wenpeng Elshenhab, Ahmed M. Fu, Yili Department of Electrical Engineering Benha Faculty of Engineering Benha University Benha Egypt State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin150080 China Department of Mechatronics and Robotics Engineering Faculty of Engineering South Valley University Qena Egypt First Affiliated Hospital Harbin Medical University Harbin150001 China School of Life Science and Technology Harbin Institute of Technology Harbin150080 China Department of Mathematics Faculty of Science Mansoura University Mansoura35516 Egypt

Accurate identification of the subthalamic nucleus (STN) borders is time-consuming, relying heavily on the neurosurgeon expertise in manually interpreting the electrophysiological signals. Local field potentials (LFPs) have garnered imperative attention due to their strong correlation with the STN. However, existing detection models often face challenges with high computational complexity, hyperparameter optimization and lack of explainability, making them unreliable for clinicians. Therefore, this study introduces an explanatory framework using convolutional neural networks (CNN) for detecting the STN region from LFPs. Continuous wavelet transform is employed to convert LFPs signals into scalogram images, which are then processed by sixteen CNN models. We evaluated our framework by examining the impact of various limiting factors on the classification performance, including model size, learning rate (LR), optimizers and data scaling. Deep features are extracted from the top-performing CNN architectures to capture rich representations of the scalograms. These features are then fused and classified using k-nearest neighbour algorithm. Gradient-weighted class activation mapping is used to explain the decisions made by the proposed model. Our approach achieved an accuracy of 99.61%, outperforming individual CNN models for STN localization. The experimental results revealed that CNN models, embedded with additional hyperparameters and layers, generally outperformed smaller models. Besides, low LR significantly enhanced the performance compared to high LR. Moreover, features extracted from untuned networks produced lower performance than tuned networks. The proposed system could revolutionize deep brain stimulation surgery by increasing efficiency and reducing reliance on clinician expertise for STN detection. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.

关键词： Wavelet transforms

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Simultaneous achievement of large strain, low hysteresis, and high-temperature stability in textured BT-based piezoelectric ceramics

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Journal of Advanced Ceramics 2025年第2期14卷 131-139页

作者： Xiyue Zhang Zhe Wang Peng Li Yingchun Liu Juan Du Jigong Hao Wei Li Jiwei Zhai School of Materials Science and Engineering Laboratory of Sensitive Materials and Devices Shandong Department of EducationLiaocheng UniversityLiaocheng 252059China Functional Materials and Acoustooptic Instruments Institute Harbin Institute of TechnologyHarbin 150080China School of Materials Science and Engineering Tongji UniversityShanghai 201804China

BaTiO_(3) (BT)-based piezoceramics with large temperature-stable strains and low hysteresis are urgently needed for high-precision actuators because of increasing environmental problems. Here, tetragonal [001]c-textured (Ba_(0.98)Ca_(0.02))(Ti_(0.96)Sn_(0.04))O_(3) (BCTS) ceramics with a texture degree (F_(001)) of ~98% were obtained via the templated grain growth (TGG) method. A large maximum unipolar strain (S_(max)) of ~0.24% with a low strain hysteresis (Hs) of ~3.8% and an optimized piezoelectric strain coefficient (d_(33)^(*)) of ~1124 pm·V^(−1) are simultaneously achieved in the textured BCTS ceramics. Moreover, the variation in the strain response is less than 20% from room temperature (RT) to 100℃ for the textured ceramics. The underlying mechanism for the optimized strain performance could be attributed to the synergetic effect of the polarization extension and a fine domain structure. This work provides new insight for achieving a balance of multiple strain properties (large strain, low hysteresis, and high-temperature stability) in BT-based ceramics, showing the widespread application prospects of lead-free ceramics in high-precision actuators.

关键词： textured ceramics strain performance hysteresis temperature stability

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Achieving high strength-ductility synergy in TiB_(w)/near α-Ti composites by ultrafine grains and nanosilicides via low-temperature severe plastic deformation

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Journal of Materials science & technology 2024年第35期202卷 253-266页

作者： Changjiang Zhang Xiaojian Liang Yonggang Sun Shuzhi Zhang Ruipeng Guo Hong Feng Fantao Kong Peng Cao College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Yanshan UniversityQinhuangdao 66004China Department of Chemical and Materials Engineering The University of AucklandPrivate Bag 92019Auckland 1142New Zealand

The common problem of low strength-ductility matching prevails in near-αhigh-temperature titanium matrix composites(TMCs).In this work,the design strategy of ultrafine grains and dispersed(Ti,Zr)_(6)Si_(3) nanoprecipitates in the microstructure of TiB_(w)/nearα-Ti composites via low-temperature isothermal mul-tidirectional forging(IMDF),is expected to break the trade-offdilemma between strength and *** results show that with the decrease in the temperature of IMDF,the grain scale decreased from 0.98 to 0.59μm,and the location of silicide precipitation shifted from phase boundaries and grain boundaries toα-grain boundaries and intracrystalline *** experiments confirm that the local segregation of Si and the temperature of thermomechanical deformation are the key factors affecting the precipitation behavior of *** the decrease of the deformation temperature,the precipitation mechanism of silicides changes from a single diffusion-controlled precipitation to the coupling of two mechanisms,namely,elemental diffusion and dislocation-assisted nucleation,which facilitates the successive precip-itation of nanometer-sized silicides at the grain boundaries and in the inner *** ultimate ten-sile strength(UTS)and elongation of the composites were substantially increased after IMDF at 950 and 800℃,especially the excellent performance at 800℃,where the strength reached 1320.3 MPa and the elongation was 5.8%.The room and high-temperature strengthening and failure mechanisms of the com-posites are analyzed and discussed,and the yield strength(YS)increments provided by various strength-ening mechanisms at room temperature are quantified,aiming to provide a potential preparation strategy for the synergistic strengthening of near-αTMCs with ultrafine grains and nanoparticles.

关键词： Titanium matrix composites High temperature titanium alloy Severe plastic deformation Ultrafine grain Silicides Strengthening mechanisms

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Versatile BiFeO_(3) shining in piezocatalysis:From materials engineering to diverse applications

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Journal of Advanced Ceramics 2025年第3期14卷 1-27页

作者： Jian Dai Zhenhao Fan Hang Xie Yitao Jiao Fu Huang Ahmad Azmin Mohamad Yunfei Chang Yangke Long Dawei Wang School of Instrumentation Science and Engineering Harbin Institute of TechnologyHarbin 150080China Institute of Applied Physics and Materials Engineering University of MacaoAvenida da UniversidadeMacao 999078China Energy Materials Research Group(EMRG) School of Materials and Mineral Resources EngineeringUniversiti Sains MalaysiaNibong Tebal 14300Malaysia Zhengzhou Research Institute Harbin Institute of TechnologyZhengzhou 450046China Department of Transportation and Environment Shenzhen Institute of Information TechnologyShenzhen 518172China

The growing global demand for sustainable solutions to address energy and environmental challenges has spurred significant interest in catalytic *** has emerged as a sustainable technology for environmental remediation and energy conversion because of its unique characteristics of harvesting mechanical energy into electrochemical *** BiFeO_(3)(BFO)stands out among a range of piezocatalysts for its distinctive integration of piezoelectric,multiferroic,and optical *** review critically examines piezocatalytic mechanisms,including energy band theory,screening charge effects,and displacement current theory,revealing the intricate roles of internal charges,screening charges,and piezoelectric electrons in driving catalytic ***,the evolution of BFO-based piezocatalysis is systematically reviewed,emphasizing its structural characteristics,representative synthesis methods,performance optimization strategies,and diverse applications,such as organic pollutant degradation,H_(2) production,H_(2)O_(2)generation,CO_(2)reduction,and *** particular,the underestimated ferroelectric polarization effect of BFO on CO_(2)reduction is critically analyzed and *** review identifies critical challenges and outlines future research directions to advance high-efficiency BFO-based piezocatalytic ***,this comprehensive analysis underscores the potential of BFO in piezocatalysis,bridging materials engineering with practical applications and offering insights into future advancements.

关键词： BiFeO_(3)(BFO) piezocatalysis piezoelectric effect environmental remediation energy conversion

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