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Cutting path-dependent machinability of SiCp/Al composite under multi-step ultra-precision diamond cutting

Chinese Journal of Aeronautics 2021年第4期34卷 241-252页

作者： Shijin LU Junjie ZHANG Zengqiang LI Jianguo ZHANG Xiaohui WANG Alexander HARTMAIER Jianfeng XU Yongda YAN Tao SUN Center for Precision Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China School of Mechanical Engineering University of JinanJinan 250022China Interdisciplinary Centre for Advanced Materials Simulation Ruhr-University BochumBochum 44780Germany

Particle-tool interactions,which govern the synergetic deformation of SiC particle reinforced Al matrix composites under mechanical machining,strongly depend on the geometry of particle position residing on cutting *** the present work,we investigate the influence of cutting path on the machinability of a SiCp/Al composite in multi-step ultra-precision diamond cutting by combining finite element simulations with experimental observations and *** consistent with experimentally characterized microstructures,the simulated SiCp/Al composite is considered to be composed of randomly distributed polygonally-shaped SiC particles with a volume fraction of 25 vol%.A multi-step cutting strategy with depths of cut ranging from 2 to 10 lm is adopted to achieve an ultimate depth of cut of 10 *** material parameters and extrinsic cutting conditions utilized in finite element simulations of SiCp/Al cutting are consistent with those used in corresponding *** results reveal different particle-tool interactions and failure modes of SiC particles,as well as their correlations with machining force evolution,residual stress distribution and machined surface topography.A detailed comparison between numerical simulation results and experimental data of multi-step diamond cutting of SiCp/Al composite reveals a substantial impact of the number of cutting steps on particle-tool interactions and machined surface *** findings provide guidelines for achieving high surface finish of SiCp/Al composites by ultra-precision diamond cutting.

关键词： Cutting path Diamond cutting Finite element simulation Particle-tool interaction SiCp/Al composites

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Modeling of Drama Performance Intelligent Evaluation Driven by Multimodal Data 15th

Modeling of Drama Performance Intelligent Evaluation Driven...

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15th International Conference on Genetic and Evolutionary Computing, ICGEC 2023

作者： Song, Zhen Wu, Yufeng Zhang, Longfei Tao, Wenting Li, Lijie Ding, Gangyi Advanced Research Center for Digitalization of Traditional Drama The Central Academy of Drama 39 Dongmian Hutong Dongcheng District Beijing China Key Laboratory of Digital Performance and Simulation Technology Beijing Institute of Technology 5 Zhongguancun South Street Haidian District Beijing China Military Dance Performance Teaching and Research Office School of Military Culture National Defense University of the People’s Liberation Army of China 18 Zhongguancun South Street Haidian District Beijing China

ISBN: (纸本)9789819700677

The purpose of this study is to explore a data-driven intelligent evaluation method for drama performances, and to improve the evaluation quality of drama performances. Our research work is mainly to establish the temporal relationship between motion and musical features in dramatic performances and to construct a multimodal evaluation dataset (PEMD, Performance Evaluation Multimodal Dataset) for drama performances based on computer vision methods and deep learning technologies. Then the evaluation of drama performance is achieved by detecting and evaluating the match degree (DMD, Dramatic Match Degree) of the motion and musical features in the drama performance. The main works includes: (1) A data-driven intelligent evaluation framework for drama performance is proposed, which defines and describes the collection method, classification and feature extraction of drama performance evaluation data;(2) A sliding window computing unit based on Dramatic Stylization Annotation is proposed. As the core computing module of the drama performance evaluation architecture, it establishes the corresponding relationship between performance motion and music based on temporal features, and constructs Multimodal Evaluation Dataset (PEMD) for the drama performance;(3) Aiming at the temporal features of drama performances, a co-training method is proposed to establish the Theater Performance Evaluation Model (TPEM) and realize intelligent computing methods for drama performance intelligent evaluation. The experimental results show that the average accuracy rate (MAP Mean Average Precision) of the drama performance evaluation model proposed in this paper reaches 62.41%, showing excellent evaluation ability. © 2024, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Feature extraction

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Development and Application of a D-DOT Sensor For Peaking Capacitor Voltage Measurement in a High-Altitude Electromagnetic Pulse Simulator

Development and Application of a D-DOT Sensor For Peaking Ca...

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IEEE International Conference on Plasma Science (ICOPS)

作者： L. Cheng W. Jia K. Mei Z. Chen F. Guo W. Ding W. Wu National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi’an China College of Advanced Interdisciplinary Studies National University of Defense Technology Changsha China School of Electrical Engineering/State Key Laboratory of Electrical Insulation and Power Equipment Xi’an Jiaotong University Xi’an China

ISBN: (数字)9798350360912

ISBN: (纸本)9798350360929

In a large-scale high-altitude electromagnetic pulse (HEMP) simulator, accurately measuring the voltage of the peaking capacitor is crucial for determining the status of the output switch and assessing faults in the capacitor during device operation. This paper focuses on designing and developing a miniaturized D-dot sensor to meet the specific measurement requirements of a maximum pulse amplitude of 3 MV and a rising time of 30 ns in a complex electromagnetic environment. The sensor is designed as a coaxial structure, consisting of a substrate, coupled electrode, shielding electrode, insulation dielectric layer and BNC connector. The response characteristics of the sensor are calibrated offline using a step-wave generator with a rising time less than 3 ns. The scale factor is determined through online calibration when the sensor is compactly mounted on the outer conductor of the peaking capacitor. Calibration results demonstrate that the designed sensor has a bandwidth exceeding 100 MHz and a scale factor of 10370, with a measurement uncertainty as high as 5%. A voltage waveform reconstruction approach based on the wavelet analysis and numerically integration is proposed. A comparative analysis between two postprocessing methods, passive resistor-capacitor integration and numerical process, is conducted. The proposed D-dot sensor is utilized to measure the actual working voltage waveforms of the peaking capacitor in a vertical polarized dipole (VPD) HEMP simulator. The measurement results indicate a linear increase in voltage amplitude on the peaking capacitor, ranging from 1.3 MV to 3.7 MV, as the charging voltage of the primary drive source increases from 15 kV to 50 kV, with the rising time varying based on the operation conditions of the output switch, which can accurately reflect the operating status of the peaking circuit of the device.

关键词： Electrodes Voltage measurement Pulse measurements Capacitors Switches Wavelet analysis Time measurement

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CMAS + sea salt corrosion to thermal barrier coatings

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Corrosion Science 2023年第1期218卷

作者： Guo, Lei Zhang, Xinmu Liu, Mingguang Yang, Shuo Dai, JianWei School of Materials Science and Engineering Tianjin University Tianjin300072 China Tianjin Key Laboratory of Advanced Joining Technology Key Lab of Advanced Ceramics and Machining Technology of Ministry of Education Tianjin300072 China Naval Logistics Academy Tianjin300450 China Center for analysis and Test Tianjin University 300072 China Key laboratory for advanced corrosion and protection of aviation materials AECC Beijing Institute of Aeronautical Materials Beijing100095 China

In marine environment, sea salt and calcium-magnesium-alumina-silicate (CMAS) coexist largely endangering thermal barrier coatings (TBCs) service safety. In this study, the corrosion behavior of synthetic sea salt and CMAS to TBCs was investigated. Sea salt changed the CMAS structure, thereby decreasing its melting temperature and high-temperature viscosity. At 1200 ℃, CMAS + sea salt completely melted but CMAS did not;at 1250 ℃, both melted while CMAS + sea salt had stronger penetration ability in TBCs than CMAS. Thus, TBCs which have not been or are less affected by CMAS may be damaged due to CMAS + sea salt attack. © 2023 Elsevier Ltd

关键词： Alumina

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Vparrot Optimization Algorithm for Improved Multi-Strategy Fusion for Feature Optimization of Data in Medical and Industrial Field

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SSRN 2024年

作者： Huang, Gaoxia Wei, Jianan Yuan, Yage Huang, Haisong Chen, Hualin Key Laboratory of Advanced Manufacturing Technology Ministry of Education Guizhou University Guizhou Guiyang550025 China Guizhou Equipment Manufacturing Digital Workshop Modeling and Simulation Engineering Research Center Guizhou Guiyang550025 China

Feature selection is crucial in enhancing model performance in machine learning, data mining, and pattern recognition. In the medical-industrial domain, data often contains redundant and irrelevant features, impacting model efficiency and generalization. Meta-heuristic algorithms have shown superior performance in addressing complex problems with constraints, making them suitable for feature selection *** study proposes an improved Multi-Strategy Fusion Parrot Optimization algorithm (MIPO) tailored for optimizing feature selection. MIPO integrates four core mechanisms: balanced foraging behavior for pinpointing key features, lens imaging reverse dwell behavior for local search enhancement, vertical and horizontal cross-communication for population co-evolution, and memory-guided behavior for intelligent search direction. A pacifying behavior strategy enhances algorithm stability in complex *** study conducts exhaustive experiments, including ablation studies against mainstream algorithms, to validate MIPO's performance across various dimensions. Using the S/V transfer function, nine binary variants address diverse feature selection challenges. Results on 23 medical-industrial datasets demonstrate MIPO's efficiency and strong generalization *** integrated with KNN, SVM, and RF classifiers, MIPO significantly enhances model accuracy compared to the original parrot algorithm: 55.38%, 35.53%, and 49.59% on average, respectively. The optimal MIPO variant performs well across all classifiers, with average improvement rates of 53.91%, 34.38%, and 49.94%.This research underscores MIPO's broad applicability and robustness in feature selection for medical engineering applications. It provides empirical evidence supporting MIPO as a powerful tool for processing and analyzing complex datasets, thereby advancing feature selection technology in practical settings. © 2024, The Authors. All rights reserved.

关键词： Feature Selection

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Brain Functional Network Generation Using Distribution-Regularized Adversarial Graph Autoencoder with Transformer for Dementia Diagnosis

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Computer Modeling in Engineering & Sciences 2023年第12期137卷 2129-2147页

作者： Qiankun Zuo Junhua Hu Yudong Zhang Junren Pan Changhong Jing Xuhang Chen Xiaobo Meng Jin Hong School of Information Engineering Hubei University of EconomicsWuhan430205China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources and Hydropower ResearchBeijing100038China School of Computing and Mathematic Sciences University of LeicesterLeicesterLE17RHUK Shenzhen Institutes of Advanced Technology Chinese Academy of SciencesShenzhen518055China Faculty of Science and Technology University of MacaoMacao999078China School of Geophysics Chengdu University of TechnologyChengdu610059China Laboratory of Artificial Intelligence and 3D Technologies for Cardiovascular Diseases Guangdong Provincial Key Laboratory of South China Structural Heart DiseaseGuangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhou519041China Medical Research Institute Guangdong Provincial People’s Hospital(Guangdong Academy of Medical Sciences)Southern Medical UniversityGuangzhou519041China

The topological connectivity information derived from the brain functional network can bring new insights for diagnosing and analyzing dementia *** brain functional network is suitable to bridge the correlation between abnormal connectivities and dementia ***,it is challenging to access considerable amounts of brain functional network data,which hinders the widespread application of data-driven models in dementia *** this study,a novel distribution-regularized adversarial graph auto-Encoder(DAGAE)with transformer is proposed to generate new fake brain functional networks to augment the brain functional network dataset,improving the dementia diagnosis accuracy of data-driven ***,the label distribution is estimated to regularize the latent space learned by the graph encoder,which canmake the learning process stable and the learned representation ***,the transformer generator is devised to map the node representations into node-to-node connections by exploring the long-term dependence of highly-correlated distant brain *** typical topological properties and discriminative features can be preserved ***,the generated brain functional networks improve the prediction performance using different classifiers,which can be applied to analyze other cognitive *** on the Alzheimer’s Disease Neuroimaging Initiative(ADNI)dataset demonstrate that the proposed model can generate good brain functional *** classification results show adding generated data can achieve the best accuracy value of 85.33%,sensitivity value of 84.00%,specificity value of 86.67%.The proposed model also achieves superior performance compared with other related ***,the proposedmodel effectively improves cognitive disease diagnosis by generating diverse brain functional networks.

关键词： Adversarial graph encoder label distribution generative transformer functional brain connectivity graph convolutional network dementia

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Review of electrochemical degradation of phenolic compounds

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International Journal of Minerals,Metallurgy and Materials 2021年第9期28卷 1413-1428页

作者： You Xue Xi Hu Qian Sun Hong-yang Wang Hai-long Wang Xin-mei Hou Beijing Advanced Innovation Center for Materials Genome Engineering Collaborative Innovation Center of Steel TechnologyUniversity of Science and Technology BeijingBeijing 100083China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China State Environmental Protection Key Laboratory of Environmental Planning and Policy Simulation Chinese Academy of Environmental PlanningBeijing 100012China School of Materials Science Engineering Zhengzhou UniversityZhengzhou 450001China

Phenolic compounds are widely present in domestic and industrial sewage and have serious environmental *** oxidation(EO)is one of the most promising methods for sewage degradation because of its high efficiency,environmental compatibility,and *** this work,we present an in-depth overview of the mechanism and factors affecting the degradation of phenolic compounds by *** particular,the effects of treatment of phenolic compounds with different anode materials are discussed in *** non-active anode shows higher degradation efficiency,less intermediate accumulation,and lower energy consumption than the active *** combined with other treatment methods(biological,photo,and Fenton)presents advantages,such as low energy consumption and high degradation ***-while,the remaining drawbacks of the EO process in the phenolic compound treatment system have been ***,future re-search directions are put forward to improve the feasibility of the practical application of EO technology.

关键词： electrochemical oxidation phenolic compounds degradation mechanism anode material

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Research on the Configuration and Capacity Calculation of DC Side Dynamic Braking System

Research on the Configuration and Capacity Calculation of DC...

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HVDC (HVDC), International Conference on

作者： Yu Bai Yuexi Yang Xiao Zhou Zhenyu Du Yinghong Hu Yu Li National Key Laboratory of Advanced Power Transmission Technology Beijing Key Laboratory of DC Grid Technology and Simulation State Grid Smart Grid Research Institute Co. Ltd. Beijing China Electric Power Research Institute State Grid JiBei Electric Power Co. Ltd. Beijing China

ISBN: (数字)9798350387759

ISBN: (纸本)9798350387766

The Flexible DC Transmission technology circumvents the limitation of transmission distance caused by the charging power of AC cables. Additionally, it boasts technical advantages such as effectively isolating the interactions between onshore AC power grids and offshore wind farms, providing stable grid-connected voltage for offshore wind farms, and enabling flexible regulation of system operations. These factors make it the preferred technology for transmitting power from remote offshore wind farms. The offshore wind power flexible grid-connected system incorporates a DC-side dynamic braking system, which functions to absorb excess power injected by the wind farm and prevent system overvoltage when the AC main grid malfunctions, leading to the inability of the onshore converter station to deliver rated power. In this paper, the technical route, configuration scheme and capacity demand of DC side dynamic braking systems are studied, and the DC side dynamic braking system configuration scheme applicable to unipolar and bipolar isolated island new energy transmission flexible system is proposed, and the capacity demand of DC side dynamic braking system is analyzed, and the capacity design scheme of DC side dynamic braking system that conforms to the national calibration and meets the demand of system power balancing and fault ride-through and other requirements under the faulty AC system is proposed. The capacity design scheme of energy consuming devices is proposed in compliance with national calibration and can meet the system power balance and fault ride-through requirements in case of AC system failure and other working conditions.

关键词： HVDC transmission Systems operation Power system dynamics Layout Wind farms Power system stability Wind power generation Calibration Voltage control Standards

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Lightweight and Covalent-Crosslinked Polybenzoxazine Aerogels for Fire Resistance and Thermal Insulation

SSRN

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SSRN 2024年

作者： Li, Liangjun Zhou, Jinlong Xiao, Yunyun Zeyu, Li Liu, Saihui Zhang, Sizhao Feng, Jian Science and Technology on Advanced Ceramic Fibers and Composites Laboratory College of Aerospace Science and Technology National University of Defense Technology Changsha410073 China International Institute for Innovation Jiangxi University of Science and Technology Jiangxi Nanchang330013 China Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems Jiangxi Nanchang330013 China

The rapid advancement of modern industry and aerospace has imposed demands on thermal insulators to possess not only efficient isolation but also multifunctionality. Polybenzoxazine (PBz) aerogels with several advantages have garnered considerable research interests in recent years. Nevertheless, PBz aerogels acquired from ambient pressure drying still confront the challenge of exhibiting relatively high densities and thermal conductivities. Herein, to enrich the category and provide ideas for overcoming the above plight, hexamethylene diisocyanate (HDI) was chosen as an additive to achieve the chemical modification of the PBz aerogels. The chemical structure characterization shown that a successful reaction was occurred between the isocyanates and the hydroxyl groups, forming a urethane-bridged structure between two PBz molecular chains. In this paper, the effect of introducing HDI on the physical and thermal insulation properties of the aerogels was investigated. The HDI-modified PBz (PBz-HDI) aerogels demonstrated lower densities (0.237–0.256 g·cm−3) and thermal conductivities (0.0354−0.0370 W·m−1·K−1) in comparison with the pristine aerogel. In addition, despite an observed reduction in the residual char yields in the PBz-HDI groups, the introduction of HDI has been demonstrated to not impact their superior intrinsic flame retardancy. Given such commendable properties, PBz-HDI aerogel is expected to be a promising candidate for thermal insulation and fire resistance applications in various domains. © 2024, The Authors. All rights reserved.

关键词： Thermal insulation

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Urban constructed wetlands: Assessing ecosystem services and disservices for safe, resilient, and sustainable cities

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Frontiers of Engineering Management 2023年第4期10卷 582-596页

作者： Aamir Mehmood SHAH Gengyuan LIU Yu CHEN Qing YANG Ningyu YAN Feni AGOSTINHO Cecilia MVBALMEIDA Biagio FGIANNETTI State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing 100875China Beijing Engineering Research Center for Watershed Environmental Restoration&Integrated Ecological Regulation Beijing 100875China Advanced Interdisciplinary Institute of Environment and Ecology Beijing Normal UniversityZhuhai 519087China Key Laboratory for City Environmental Safety and Green Development of the Ministry of Education Institute of Environmental and Ecological EngineeringGuangdong University of TechnologyGuangzhou510006China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou511458China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentBeijing Normal UniversityBeijing100875China Programa de Pós-graduação em Engenharia de Produção Laboratório de Produção e Meio AmbienteUniversidade Paulista(UNIP)São Paulo04026-002Brazil

Climate change and rapid urbanization are pressing environmental and social concerns, with approximately 56% of the global population living in urban areas. This number is expected to rise to 68% by 2050, leading to the expansion of cities and encroachment upon natural areas, including wetlands, causing their degradation and fragmentation. To mitigate these challenges, green and blue infrastructures (GBIs), such as constructed wetlands, have been proposed to emulate and replace the functions of natural wetlands. This study evaluates the potential of eight constructed wetlands near Beijing, China, focusing on their ecosystem services (ESs), cost savings related to human health, growing/maintenance expenses, and disservices using an emergy-based assessment procedure. The results indicate that all constructed wetlands effectively purify wastewater, reducing nutrient concentrations (e.g., total nitrogen, total phosphorus, and total suspended solids). Among the studied wetlands, the integrated vertical subsurface flow constructed wetland (CW-4) demonstrates the highest wastewater purification capability (1.63E+14 sej/m^(2)/yr) compared to other types (6.78E+13 and 2.08E+13 sej/m^(2)/yr). Additionally, constructed wetlands contribute to flood mitigation, groundwater recharge, wildlife habitat protection, and carbon sequestration, resembling the functions of natural wetlands. However, the implementation of constructed wetlands in cities is not without challenges, including greenhouse gas emissions, green waste management, mosquito issues, and disturbances in the surrounding urban areas, negatively impacting residents. The ternary phase diagram reveals that all constructed wetlands provide more benefits than costs and impacts. CW-4 shows the highest benefit-cost ratio, reaching 50%, while free water surface constructed wetland (CW-3) exhibits the lowest benefits (approximately 38%), higher impacts (approximately 25%), and lower costs (approximately 37%) compared to other we

关键词： constructed wetland emergy ecosystem services disservices ternary diagram

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