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Atomic-resolution studies on reactions between basal dislocations and {1012} coherent twin boundaries in a Mg alloy

Journal of Materials science & technology 2021年第7期66卷 28-35页

作者： Huhu Su Xinzhe Zhou Shijian Zheng Hengqiang Ye Zhiqing Yang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesSchool of Materials Science and EngineeringUniversity of Science and Technology of ChinaShenyang110016China State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of TechnologyTianjin300130China Jihua Laboratory Foshan528251China

Reactions between basal 〈a60〉 dislocations and {1012} coherent twin boundaries(CTBs) in a Mg alloy were studied with atomic resolution. Individual dislocation-CTB reactions produced steps with residual dislocations and multiple t winnin g dislocations(TDs) gliding away, consequently resulting in TB migration. Reactions between {1012} CTBs and low-angle grain boundaries composed of basal 〈a60〉 dislocations created either basal-prismatic/prismatic-basal interfaces or asymmetric tilt grain boundaries, depending on whether TDs gliding away or not. Not only the emission of TDs by dislocation-TB reactions may drive TB migration, but also the resultant steps or facets along TBs can act as TD sources to facilitate TB migration. Our results indicate that roughness or severe loss of local coherency induced by dislocation-TB reactions does not intrinsically impede TB migration in Mg alloys. Dislocation-TB reactions may provide another feasible strategy to improve the ductility of Mg alloys, in addition to other techniques like grain refinement and texture modification.

关键词： Mg alloys Dislocation Twin boundary Migration Plastic deformation

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Cooperative adsorption performance of topological nodal surface fermions and excess electrons in a three-dimensional topological electride Ba3CrN3

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Physical chemistry chemical physics : PCCP 2025年第22期27卷 2025 May 27页

作者： Zhizuo Liu Ying Liu Zihan Li Xuefang Dai Xiaoming Zhang Guodong Liu State Key Laboratory of Reliability and Intelligence of Electrical Equipment and School of Materials Science and Engineering Hebei University of Technology Tianjin 300130 China. ying_liu@***.

Electrides and topological materials have individually been identified as promising candidates for use in electrochemical catalysis. Recently, the concept of topological electrides has emerged, where the topological fermions arise from the excess electrons characteristic of electrides, highlighting their potential in catalytic processes. In this work, we report that the topological electride BaCrN, hosting nodal surface fermions near the Fermi level, exhibits excellent adsorption properties-a critical requirement for catalytic applications. The bands forming the nodal surface are predominantly derived from the excess electrons located at the corners of the BaCrN unit cell. Due to the extensive projection of the nodal surface onto the Fermi level, BaCrN demonstrates robust adsorption characteristics, even under external biaxial strain up to 6%. Moreover, by doping holes to neutralize excess electrons, its adsorption ability is suppressed, confirming that these excess electrons play a pivotal role in the adsorption process. Overall, we reveal that the exceptional adsorption properties stem from the interplay between its topological features and the presence of excess electrons, providing insights into its catalytic potential.

关键词： Catalysis

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Fault Diagnosis Model for UAV with Small Sample Size and Imbalanced Data

Fault Diagnosis Model for UAV with Small Sample Size and Imb...

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Prognostics and System Health Management Conference (PHM-Qingdao)

作者： Guoqing Song Ke Ma Yang Yang Yanchen Dong Danyang Han Mingliang Suo School of Reliability and Systems Engineering Beihang University Beijing China No.31850 People's Liberation Army of China Beijing China National Key Laboratory of Science and Technology on Reliability and Environmental Engineering Institute of Reliability Engineering School of Reliability and Systems Engineering Beihang University Beijing China

ISBN: (数字)9798350354010

ISBN: (纸本)9798350354027

With the development of Unmanned Aerial Vehicles (UAV), their application scenarios and task requirements have become more complex, demanding higher standards for subsequent fault diagnosis and equipment maintenance. The actual flight data of UAV usually exhibits small sample sizes and imbalanced characteristics. To achieve more efficient fault prediction for UAV, this paper establishes a SMOTE-IWOA-RF fault diagnosis model. This model optimizes the Whale Optimization Algorithm (WOA) using chaotic initialization, nonlinear convergence factors, and Lévy flight strategies, resulting in better convergence accuracy and global search capability, as well as faster convergence speed. The model is compared with other classification models on data with different imbalance ratios, demonstrating that it is more efficient and accurate in UAV fault diagnosis, with the F1 score improving by about 10% compared to the pre-optimization state. Furthermore, the IWOA-RF model is combined with other data preprocessing methods, showing that SMOTE-IWOA-RF performs better on UAV operational data, indicating its practical value.

关键词： Fault diagnosis Solid modeling Accuracy Autonomous aerial vehicles Data models Whale optimization algorithms Classification algorithms Optimization Standards Convergence

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Influence of crevice width on sulfate-reducing bacteria(SRB)-induced corrosion of stainless steel 316L

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Corrosion Communications 2021年第4期4卷 33-44页

作者： Cong Wu Zhaopeng Wang Zhan Zhang Bowei Zhang Guojia Ma Qiong Yao Zhaohong Gan Junsheng Wu Xiaogang Li Institute for Advanced Materials and Technology University of Science and Technology Beijing Aeronautical Key Laboratory of Advanced Surface Engineering Technology China Aviation Manufacturing Technology Institute Key Laboratory of Space Lauching Site Reliability Technology

In the present work, the distribution of sulfate-reducing-bacteria(SRB) inside the crevice and the effect of crevice width on SRB-induced corrosion of stainless steel 316L(SS 316L) were systematically investigated. A cambered crevice configuration consisting of a convex lens and a wire beam electrode(WBE) was employed to measure the current and potential distributions under different crevice widths. Subsequently, scanning electronic microscopy(SEM), electrochemical impedance spectroscopy(EIS) and X-ray photoelectron spectroscopy(XPS) were adopted to study SRB-induced corrosion behavior of SS 316L in different crevice locations. Results show that crevice width plays an essential role in corrosion on SS 316L in crevice environment with SRB. The most severe corrosion with dense pits occurred at the crevices with 150 μm in width due to the combined effects of microbiological corrosion and crevice corrosion. In narrow crevices, corrosion is much slighter since SRB can hardly enter into the crevices to induce corrosion. In contrast, the crevices with 700 μm in width suffer the mildest corrosion because the influence of crevice corrosion is negligible with a weakened crevice corrosion tendency. Additionally, it was found that SRB could affect the composition of the passive film and destroy its compactness, thus accelerate the crevice corrosion of SS 316L in artificial seawater. The findings of this work are beneficial to understanding the mechanisms of MIC-induced corrosion in various environments.

关键词： SS 316L SRB WBE Crevice corrosion

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Failure Mechanism Analysis and reliability Evaluation of Wind Turbine Pitch Control System 12

Failure Mechanism Analysis and Reliability Evaluation of Win...

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12th International Conference on Quality, reliability, Risk, Maintenance, and Safety engineering, QR2MSE 2022

作者： Wang, Yanfang Chen, Ying Yue, Dawei Zhu, Guixia Science and Technology on Reliability and Environmental Engineering Laboratory Beihang University Beijing China School of Electrical Engineering Hebei University of Technology Tianijin China Research Institute of Nuclear Power Operation China

ISBN: (纸本)9781839538360

In recent years, the new clean energy mainly based on wind energy has been developed rapidly, and the reliability of wind turbines has also received more and more attention. In view of the problems existing in the current reliability evaluation, such as dependence on failure data and lack of understanding of failure mechanism, a reliability evaluation method based on failure mechanism tree is proposed in this paper and the reliability evaluation of wind turbine pitch control system is completed with consideration of the correlations of the failure mechanisms, which is achieved by combining the system failure mechanism and failure behavior from the perspective of performance parameters. © 2022 IEEE.

关键词： Wind turbines

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Simulation Analysis and Belief reliability Evaluation of Electromagnetic Performance of Electronic Products 12

Simulation Analysis and Belief Reliability Evaluation of Ele...

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12th IEEE Global reliability and Prognostics and Health Management, PHM-Nanjing 2021

作者： Chu, Qiaohui Chen, Ying Science And Technology On Reliability And Environmental Engineering Laboratory Beihang University Beijing China

ISBN: (纸本)9781665401302

This paper proposes a simulation analysis method of anti-electromagnetic interference based on field-circuit co-simulation for a case. Without considering the degradation of electronic products, the interdisciplinary equation, margin equation and measurement equation are established based on the margin reliability principle and the uncertainty principle, which are used to conduct a belief reliability assessment of anti- electromagnetic interference before products are put into use. Based on the evaluation results, optimization and improvement measures are proposed to improve products' reliability. The application of belief reliability theory and method in electromagnetic simulation analysis is realized, and it is of great significance to the improvement of existing electromagnetic simulation analysis methods. Finally, the paper summarizes the full text and looks forward to the follow-up work. © 2021 IEEE.

关键词： reliability analysis

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LLM-based Framework for Bearing Fault Diagnosis

arXiv

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arXiv 2024年

作者： Tao, Laifa Liu, Haifei Ning, Guoao Cao, Wenyan Huang, Bohao Lu, Chen Hangzhou International Innovation Institute Beihang University Hangzhou China Institute of Reliability Engineering Beihang University Beijing China Science & Technology on Reliability & Environmental Engineering Laboratory Beijing China School of Reliability and Systems Engineering Beihang University Beijing China

Accurately diagnosing bearing faults is crucial for maintaining the efficient operation of rotating machinery. However, traditional diagnosis methods face challenges due to the diversification of application environments, including cross-condition adaptability, small-sample learning difficulties, and cross-dataset generalization. These challenges have hindered the effectiveness and limited the application of existing approaches. Large language models (LLMs) offer new possibilities for improving the generalization of diagnosis models. However, the integration of LLMs with traditional diagnosis techniques for optimal generalization remains underexplored. This paper proposed an LLM-based bearing fault diagnosis framework to tackle these challenges. First, a signal feature quantification method was put forward to address the issue of extracting semantic information from vibration data, which integrated time and frequency domain feature extraction based on a statistical analysis framework. This method textualized time-series data, aiming to efficiently learn cross-condition and small-sample common features through concise feature selection. Fine-tuning methods based on LoRA and QLoRA were employed to enhance the generalization capability of LLMs in analyzing vibration data features. In addition, the two innovations (textualizing vibration features and fine-tuning pre-trained models) were validated by single-dataset cross-condition and cross-dataset transfer experiment with complete and limited data. The results demonstrated the ability of the proposed framework to perform three types of generalization tasks simultaneously. Trained cross-dataset models got approximately a 10% improvement in accuracy, proving the adaptability of LLMs to input patterns. Ultimately, the results effectively enhance the generalization capability and fill the research gap in using LLMs for bearing fault diagnosis. Copyright © 2024, The Authors. All rights reserved.

关键词： Semantics

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A Measurement Amplification Method for TSV Weak Resistance 3

A Measurement Amplification Method for TSV Weak Resistance

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2022 3rd International Conference on Electrical technology and Automatic Control, ICETAC 2022

作者： Gong, Tao Zeng, Sheng Chen, Si Lu, Xiangjun Shao, Dengyun School of Materials Science and Engineering Xia Men University of Technology Xiamen361024 China Nanjing Electronic Devices Institute Nanjing210016 China Science and Technology on Reliability Physics and Application of Electronic Component Laboratory The Fifth Electronics Research Institute of the Ministry of Industry and Information Technology Guangzhou511370 China

In the TSV electromigration test process, this paper has carried out relevant research on how to accurately measure TSV resistance and make it conducive to the observation of standard instruments, aiming at the problem that the resistance value of TSV reaches the magnitude of a microburst. Observing the resistance value change in the electromigration process is challenging. This paper analyzes and designs a measurement circuit for TSV. This circuit uses the cascade of an integrated amplifier. It combines with the four-probe method to amplify the TSV resistance change signal based on accurate measurement of TSV resistance, which is more conducive to the measurement of standard instruments and makes it easier to observe the change of resistance when TSV electromigration occurs. © Published under licence by IOP Publishing Ltd.

关键词： Electromigration

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reliability evaluation of avionics system with imperfect fault coverage and propagated failure mechanisms

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Chinese Journal of Aeronautics 2020年第12期33卷 3437-3446页

作者： Ying CHEN Song YANG Rui KANG Science and Technology on Reliability and Environmental Engineering Laboratory Beihang UniversityBeijing 100083China

Fault tolerance designs are essential techniques for systems that require high levels of reliability,such as aircraft or spacecraft control *** Fault Coverage(IFC)may lead to the failure of a system or subsystem even with adequate *** studies of IFC mostly concentrated on evaluating Coverage Factor(CF),whereas the system failure behaviors with IFC have rarely been *** that occur in low-layer may be covered by ***,if the coverage is imperfect,uncovered failure will have functional and physical impact on the system *** this thesis,the failure behavior and reliability of IFC of multi-layer systems are studied and a Binary Decision Diagram(BDD)-based modeling and simulation method are proposed to evaluate system *** a case,the failure behavior of an aero engine electronic controller with IFC is *** results show that the IFC may impact system behavior without taking the IFC into account,the system maintenance intervals may reduce,and thus the maintenance costs will increase.

关键词： Acceleration Binary Decision Diagram(BDD) Failure mechanism Imperfect Fault Coverage Multi-layer system reliability evaluation

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A Traffic-Fractal-Element-Based Congestion Model Considering the Uneven Distribution of Road Traffic

SSRN

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SSRN 2023年

作者： Zheng, Xiangyu Huang, Ning Zhang, Xin School of Reliability and Systems Engineering Beihang university Beijing China Science and Technology on Reliability and Environmental Engineering Laboratory Beihang university Beijing China

The uneven distribution of road traffic has been proved to play a crucial role in congestion evolution within transportation networks. Establishing congestion models to explore global congestion evolution under its impact is of great significance for predicting congestion. Current congestion models commonly describe the uneven distribution of traffic on roads through continuous differential equations or the simulation of vehicles operational mechanisms by which to model traffic flow dynamics. However, these models fail to directly reveal the mechanism by which the uneven distribution characteristics affect congestion, which makes it difficult to uncover the fundamental factors that affect congestion evolution and general laws for predicting ***, this paper first constructs traffic fractal elements (TFE) based on the fractal characteristics exhibited by uneven traffic distribution. A local parameter namely the load duty ratio (LDR) is introduced to represent the uneven distribution level of TFE. By employing fractal interpolation functions, we model road traffic as the iterations of TFE. Then we define the fractal evolution rule and the load transfer rule to inscribe the relationship equation between global congestion evolution and the LDR, ultimately establishing a TFE-based ***, the proposed model is validated using empirical data from AMAP and simulation data from a calibrated Cellular Automata (CA) model. Finally, by comparing the results with a CA-based congestion model, the LDR of TFE is confirmed to be a comprehensive parameter affecting congestion evolution. By simulating and fitting the congestion evolution data under different LDRs, our proposed model demonstrates its value in congestion prediction and analysis. © 2023, The Authors. All rights reserved.

关键词： Cellular automata

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