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Phonon Transport Across Gan-Diamond Interface: The Nontrivial Role of Pre-Interface Vacancy-Phonon Scattering

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SSRN 2023年

作者： Yang, Chao Wang, Jian Ma, Dezhi Li, Zhiqiang He, Zhiyuan Liu, Linhua Fu, Zhiwei Yang, Jia-Yue School of Energy and Power Engineering Shandong University Jinan250100 China Science and Technology on Reliability Physics and Application of Electronic Component Laboratory China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou510610 China Optics & Thermal Radiation Research Center Institute of Frontier and Interdisciplinary Science Shandong University Qingdao266237 China

Diamond substrate with superior thermal conductivity has been the most promising heat sink to solve the heat dissipation issues in GaN-based power electronics. The phonon transport behaviors across the GaN-diamond interface crucially determine the thermal performance and still remain largely unexplored especially considering the presence of pre-interface vacancies. Herein, the influence of localized high-concentration Ga/N atomic vacancies on phonon transport across the GaN-diamond interface is fully investigated using non-equilibrium molecular dynamics. The calculated interface thermal resistance (ITR) of the perfect GaN-diamond interface at room temperature is approximately 1.5 m2·K/GW, consistent with prediction of the diffusion mismatch model. After introducing the Ga/N vacancies at a concentration of 30%, the existence of vacancy-phonon scattering increases the interfacial thermal resistance (ITR) by up to 67%. Analyzing the phonon density of states and the spectral heat current, the heat flux contributed by GaN high-frequency phonons decreases after introducing vacancy defects. This is attributed that the vacancy-phonon scattering in GaN enhances anharmonic phonon scattering, and the phonon energy is redistributed among different phonon modes. Moreover, the collective vibration of propagation phonons is disrupted randomly by the vacancy-phonon scattering. This work aims to understand the influence of vacancy-phonon scattering on the phonon transport across GaN-diamond interface and provide helpful guidance to engineering such interface for better heat dissipation performance. © 2023, The Authors. All rights reserved.

关键词： Diamonds

Distribution Optimization of the Error Sensors for Active Noise Control of a Fairing

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Distribution Optimization of the Error Sensors for Active No...

第八届国际振动工程会议

作者： Zhang Wen-Yong Yuan Kai Niu Mu-Qing Zhang Zhong Chen Li-Qun School of Science Harbin Institute of Technology Science and Technology on Reliability and Environment Engineering Laboratory Beijing Institute of Structure and Environment Engineering

In the design of an active noise control system for the fairing of a launch vehicle,the distribution of the error sensors directly affects the noise reduction performance. In this paper,an acoustic-structural coupled model of a fairing is established with a finite element method. The acoustic paths originated from the noise sources and the controlled loudspeakers to the error sensors are identified with a state subspace method. An active noise control system is constructed with a multiple-input-multiple-ouput Fx-LMS algorithm. Taking the minimum global sound potential energy as the optimization objective, the locations of error sensors are optimized with genetic algorithm. The results show that the optimization method of error sensors location based on genetic algorithm can quickly converge to the optimal solution, and the global acoustic potential near the payload can be reduced by 87.5 %. Compared with centralized distribution and dispersed distribution, The optimal distribution scheme obtained by genetic algorithm takes into account the magnitude of acoustic potential energy reduction at the layout point and the distribution of measuring points, so as to minimize the global sound potential energy.

关键词： Distribution Optimization of the Error Sensors for Active Noise Control of a Fairing Active

Anomaly Detection Via Kpis for Software Performance Failures

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SSRN 2022年

作者： Wang, Shuguang Lu, Minyan Kong, Shiyi Ai, Jun Wang, Jie Wong, W. Eric The Key Laboratory on Reliability and Environment Engineering Technology School of Reliability and Systems Engineering Beihang University Beijing100191 China Department of Computer Science University of Texas at Dallas 2601 N Floyd Road RichardsonTX75083 United States

As cloud services have become more popular, high-reliability requirements for distributed storage systems have also increased significantly. However, the software systems often suffer performance failures during long-term running. Anomaly detection based on performance indicators is an effective approach for performance failures. To handle the complexity of the distributed databases, this paper proposes a novel anomaly detection methodology via key performance indicators monitored at different levels. Then, a variance inflation factor (VIF) feature selection method is proposed to reduce the multicollinearity problem in the multivariate time series of performance indicators. For a long-running software system, some unavoidable noise will be introduced when monitoring these performance indicators. Therefore, it is necessary to explore the suitable feature processing method to enhance features and eliminate noise interference from indicators. Discrete wavelet analysis has a superior performance in feature extraction in signal analysis. Thus, in this paper, discrete wavelet transform is modified to create an adaptive DWT for noise reduction and feature extraction by taking advantage of the multiresolution analysis. Then, unsupervised anomaly detection algorithms are used to detect the expected indicator outliers. The anomaly detection performance of the proposed method is evaluated in terms of precision, recall, and the F1-score. Finally, this approach is verified through the experiments conducted on Cassandra, and the F1-score is 0.974 which means this approach is effective. © 2022, The Authors. All rights reserved.

关键词： Benchmarking

Thermal cycling creep properties of a directionally solidified superalloy DZ125

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Journal of Materials science & technology 2022年第9期104卷 269-284页

作者： Wenrui An Satoshi Utada Xiaotong Guo Stoichko Antonov Weiwei Zheng Jonathan Cormier Qiang Feng Beijing Advanced Innovation Center for Materials Genome Engineering State Key Laboratory for Advanced Metals and MaterialsUniversity of Science and Technology BeijingBeijing 100083China Institut Pprime UPR CNRS 3346Department of Physics and Mechanics of MaterialsISAE-ENSMABP4010986961 Futuroscope Chasseneuil CedexFrance China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou 510610China Department of Microstructure Physics and Alloy Design Max-Planck-Institut für Eisenforschung GmbHDüsseldorf 40237Germany

Aero-engine turbine blades may suffer overheating during service,which can result in severe microstructural and mechanical degradation within tens of *** this study,the thermal cycling creep under(950℃/15 min+1100℃/1 min)-100 MPa was performed on a directionally solidified superalloy,*** effects of overheating and thermal cycling on the creep properties were evaluated in terms of creep behavior and microstructural evolution against isothermally crept specimens under 950℃/100 MPa,950℃/270 MPa,and 1100℃/100 *** results indicated that the thermal cycling creep life was reduced dramatically compared to the isothermal creep under 950℃/100 *** plastic creep deformation mainly occurred during the overheating stage during the thermal cycling *** thermal cycling creep curve exhibited three stages,similar to the 1100℃isothermal creep,but its minimum creep rate occurred at a lower creep *** overheating events caused severe microstructural degradation,such as substantial dissolution ofγ'phase,earlier formation of raftedγ'microstructure,widening of theγchannels,and instability of the interfacial dislocation *** microstructural degradation was the main reason for the dramatic decrease in thermal cycling creep life,as the thermal cycling promoted more dislocations to cut intoγ'phase and more cracks to initiate at grain boundaries,carbides,and residual eutectic *** study underlines the importance of evaluating the thermal cycling creep properties of superalloys to be used as turbine blades and provides insights into the effect of thermal cycling on directionally solidified superalloys for component design.

关键词： Directional solidified superalloy Thermal cycling creep Overheating Creep properties Microstructural degradation

NSPG-Miner: Mining Repetitive Negative Sequential Patterns

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arXiv

arXiv 2025年

作者： Li, Yan Wang, Zhulin Liu, Jing Guo, Lei Fournier-Viger, Philippe Wu, Youxi Wu, Xindong School of Economics and Management Hebei University of Technology Tianjin300401 China School of Artificial Intelligence Hebei University of Technology Tianjin300401 China State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin300401 China College of Computer Science and Software Engineering Shenzhen University Shenzhen518061 China Hebei Key Laboratory of Big Data Computing 300401 China Key Laboratory of Knowledge Engineering with Big Data The Ministry of Education of China Hefei University of Technology Hefei230009 China

Sequential pattern mining (SPM) with gap constraints (or repetitive SPM or tandem repeat discovery in bioinformatics) can find frequent repetitive subsequences satisfying gap constraints, which are called positive sequential patterns with gap constraints (PSPGs). However, classical SPM with gap constraints cannot find the frequent missing items in the PSPGs. To tackle this issue, this paper explores negative sequential patterns with gap constraints (NSPGs). We propose an efficient NSPG-Miner algorithm that can mine both frequent PSPGs and NSPGs simultaneously. To effectively reduce candidate patterns, we propose a pattern join strategy with negative patterns which can generate both positive and negative candidate patterns at the same time. To calculate the support (frequency of occurrence) of a pattern in each sequence, we explore a NegPair algorithm that employs a key-value pair array structure to deal with the gap constraints and the negative items simultaneously and can avoid redundant rescanning of the original sequence, thus improving the efficiency of the algorithm. To report the performance of NSPG-Miner, 11 competitive algorithms and 11 datasets are employed. The experimental results not only validate the effectiveness of the strategies adopted by NSPG-Miner, but also verify that NSPG-Miner can discover more valuable information than the state-ofthe-art algorithms. Algorithms and datasets can be downloaded from https://***/wuc567/PatternMining/tree/master/NSPG-Miner. Copyright © 2025, The Authors. All rights reserved.

关键词： Miners

reliability-Aware Network Slicing based on Multi-Objective Optimization

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Reliability-Aware Network Slicing based on Multi-Objective O...

Congress on Evolutionary Computation

作者： Qiqi Xia Jin Wang Chengqiang Huang Xin Yao Research Institute of Trustworthy Autonomous Systems (RITAS) Southern University of Science and Technology Shenzhen China Department of Computer Science and Engineering Guangdong Key Laboratory of Brain-inspired Intelligent Computation Southern University of Science and Technology Shenzhen China Reliability Technology Lab Huawei Technologies Co. Ltd. Shenzhen China Department of Computing and Decision Sciences Lingnan University Hong Kong SAR China

ISBN: (数字)9798350308365

ISBN: (纸本)9798350308372

Network slicing is an essential technology in 5G and the forthcoming 6G networks. It aims to embed multiple virtual networks, i.e., network slices, on top of a shared substrate network to meet diverse service requirements. While a considerable body of existing research strives to maximize overall profits by meeting the resource demands of the network slices, optimizing their reliability is frequently overlooked. In this paper, we formalize the network slicing problem as a multi-objective optimization problem that aims to maximize total profits and reliability of network slices. To tackle this problem, we propose a new multi-objective optimization approach that improves over the state-of-the-art algorithm, which can achieve good approximate Pareto front results balancing total profits and reliability of network slices. The performance of our proposed method is evaluated on both artificial and real-world network topologies. Experimental results demonstrate the superior performance of our proposed method compared to the baseline algorithm, outperforming the latter in 92% of instances in terms of the Hypervolume (HV) metric.

关键词： Measurement 6G mobile communication Costs Network topology Network slicing Evolutionary computation Approximation algorithms

A Compressive-Shear Biaxial Stress Field Model for Analyzing the Anisotropic Mechanical Behavior of Nanotwinned Diamond

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SSRN 2023年

作者： Ren, Yabin Yang, Bo Su, Yang Liu, Yimeng Huang, Rui Zhao, Libin Hassan, M.A. Hu, Ning School of Mechanical Engineering State Key Laboratory of Reliability and Intelligence Electrical Equipment National Engineering Hebei University of Technology Tianjin300401 China Industrial and Manufacturing Department Faculty of Innovative Design Engineering Egypt Japan University for Science and Technology Alexandria New Borg El-Arab City21934 Egypt

Synthetic nanotwinned diamond (Nt-D) with unprecedented hardness and toughness is an ideal material for manufacturing ultra-precision cutting tools. However, the existing surface formation mechanism is no longer applicable to Nt-D. It is thus imperative to investigate the surface formation mechanism of Nt-D under complex stress fields. Here, we developed a compressive-shear biaxial stress field model to study the extreme anisotropic mechanical behavior of Nt-D. It was found that graphitization occurred in all shear directions of the Nt-D (0001) plane through the microstructure evolution of 2H-diamond, 4H-diamond, 6H-diamond, and 9R-diamond, in which the stress release mechanism was accompanied by partial slips in certain specific crystal directions such as . In addition, the generalized stacking fault energy calculation indicates that the partial slip in 6H- and 9R-diamonds is mainly attributed to the adjacent interlayer slip energy barrier. These results expand our understanding of the surface formation mechanism of Nt-D and will aid in the manufacturing of a new generation of ultra-precision cutting tools. © 2023, The Authors. All rights reserved.

关键词： Stacking faults

Boron Nitride Hollow Microtube with Nanosheets Directionally Covering the Tube Wall: Preparation, Optical and Adsorption Property

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SSRN 2023年

作者： Ji, Yuchun Li, Zhengde Zhang, Laiping Wang, Jilin Li, Wenbiao Chen, Wenzhuo Zheng, Guoyuan Long, Fei Zou, Zhengguang School of Materials Science and Engineering Guangxi Key Laboratory of Optical and Electronic Materials and Devices Guilin University of Technology Guilin541004 China China Electronic Product Reliability and Environmental Testing Institute Guangdong511370 China

In this paper, a novel Boron nitride hollow microtube (BNHM) structure by annealing assisted high-pressure etching method. The products were characterized by XRD, FTIR, Raman, XPS, SEM, TEM, TGA, BET, UV-vis, and PL. The result shows that the sample displayed a one-dimensional hollow tube structure directionally covered with nanosheets. The average inner diameter of the hollow tube is 1 μm with a length of 2-4.5 μm. And the wall thickness of the hollow tube structure is about 100 nm. In addition, the band gap value of the sample is 5.51 eV presenting the strongest emission peak at 225 nm. The specific surface area of the sample is 272.6 m2·g-1, showing good adsorption efficiency on Congo red (absorbed 75% in 5 min). Meanwhile, the possible growth mechanism of BNHM is also discussed. © 2023, The Authors. All rights reserved.

关键词： Energy gap

Three-Step Growth of Aln Films on Sapphire Substrates by Metal Nitride Vapor Phase Epitaxy

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SSRN 2023年

作者： Lin, Xiangyu Zhang, Hui Li, Chaoyuan Xie, Xinjian Bian, Lifeng Chen, Guifeng State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin300130 China School of Materials Science and Engineering Hebei University of Technology Tianjin300130 China Hebei Engineering Laboratory of Photoelectronic Functional Crystals Hebei University of Technology Tianjin300130 China Frontier Institute of Chip and System Fudan University Shanghai200433 China

Control of the growth process is important for growing high-quality AlN films. In this work, AlN films were grown on c-plane sapphire substrates by metal nitride vapor phase epitaxy(MNVPE). Interlayer was added between the buffer layer and the formal layer, and the effect of the V/III ratio of the interlayer on the crystalline quality, surface morphology and stress evolution of the films was explored. An interlayer with proper V/III ratio can provide a stable transition from 3D growth mode to 2D growth mode, while high V/III ratio induce film separation. The optimum V/III ratio for the interlayer was found to be 11050, and the films obtained under this parameter had a FWHM of 641 arcsec for (002) plane and 840 arcsec for (102) plane, with an optical transmittance of 88%. And the film separation phenomenon was found on the three-step-growth samples with high V/III ratio, which was thought to be caused by being in 3D growth mode for a long time. © 2023, The Authors. All rights reserved.

关键词： Nitrides