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A Survey on 3D Visual Tracking of Multicopters

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International Journal of Automation and computing 2019年第6期16卷 707-719页

作者： Qiang Fu xiang-yang chen Wei He School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing 100083China Institute of Artificial Intelligence University of Science and Technology BeijingBeijing 100083China

Three-dimensional(3 D) visual tracking of a multicopter(where the camera is fixed while the multicopter is moving) means continuously recovering the six-degree-of-freedom pose of the multicopter relative to the camera. It can be used in many applications,such as precision terminal guidance and control algorithm validation for multicopters. However, it is difficult for many researchers to build a 3 D visual tracking system for multicopters(VTSMs) by using cheap and off-the-shelf cameras. This paper firstly gives an overview of the three key technologies of a 3 D VTSMs: multi-camera placement, multi-camera calibration and pose estimation for multicopters. Then, some representative 3 D visual tracking systems for multicopters are introduced. Finally, the future development of the 3D VTSMs is analyzed and summarized.

关键词： Multicopter three-dimensional(3D)visual tracking camera placement camera calibration pose estimation

HEAT-RESISTANT COMPOSITES CURED BY ELECTRON BEAM

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Chinese Journal of Polymer Science 2001年第1期19卷 53-57页

作者： Jian-wen Bao yang Li xiang-bao chen Feng-mei Li National Key Lab of Advanced Composites Institute of Aeronautical Materials Beijing 100095 China National Key Lab of Advanced Composites Institute of Aeronautical Materials Beijing 100095 China National Key Lab of Advanced Composites Institute of Aeronautical Materials Beijing 100095 China Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100877 China

Electron beam (EB) curing of composites has many advantages. Heat-resistant EB-curing composites could substitute polyimide composites used in aeronautical engines. In this paper, the effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical analysis (DMA). The experimental results show that the mechanical properties of the composites cured by EB could meet the specifications of aeronautical engines at 250 degreesC.

关键词： electron beam curing composites epoxy heat-resistance

Elevated-temperature tribological behavior of Ti–B–C–N coatings deposited by reactive magnetron sputtering

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Rare Metals 2015年第12期34卷 838-843页

作者： xiang-yang chen Shao-Fu Huang Sheng-Li Ma Run Huang Jin Zhang Hai-Xia Hu School of Mechanical Engineering Anhui University of Science and Technology State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University School of Materials Science and Engineering Anhui University of Science and Technology

Quaternary Ti–B–C–N coatings with various carbon contents were deposited on high-speed steel (HSS) substrates by reactive magnetron sputtering (RMS) system. The elevated-temperature tribological behavior of Ti–B–C–N coatings was explored using pin-on-disk tribometer, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The present results show that the steady-state friction coefficient value and the instantaneous friction coefficient fluctuation range of Ti–B–C–N coatings decrease as carbon content increases at 100 and 300°C, while the steady-state friction coefficient value of all Ti–B–C–N coatings becomes higher than 0.4 at 500°C. As ambient temperature increases, the running-in periods of all Ti–B–C–N coatings become shorter. Wear damage to Ti–B–C–N coatings during sliding at elevated temperature is mainly caused by adhesive wear, and adhesive-wear damage to Ti–B–C–N coatings increases as ambient temperature increases; however, higher carbon content is beneficial for decreasing the adhesive-wear damage to Ti–B–C–N coatings during sliding at elevated temperature.

关键词： Tribological behavior Ti–B–C–N coatings Reactive magnetron sputtering Elevated temperature

Interregional Value-Added Tax in the Era of E-Commerce: Tax Policy Design Based on Big Data from Online Retailing

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Journal of Social Computing 2024年第1期5卷 46-57页

作者： Yu chen Luwei xiang Hu yang School of Public Finance and Taxation Central University of Finance and EconomicsBeijing 100008China School of Management and Economics The Chinese University of Hong KongShenzhen 518172China School of Information Central University of Finance and EconomicsBeijing 100008China

The value-added tax(VAT)in China is levied and allocated based on the origin *** the background of the increasing substitution of online retail for traditional offline retail,this mechanism will exacerbate the disparity of regional tax revenue,and intensify tax competition among local ***,reconsidering the allocation mechanism of value-added tax in China can be an important policy decision,and it is influenced by various economic and social ***,we utilize large-scale retail transaction data from an e-commerce platform to measure regional disparities in retail and consumption among different regions and then reveals present tax policy results in revenue imbalance in different ***,we establish a model based on game theory to illustrate how the origin principle leads to fierce tax competition among ***,by establishing and solving tax allocation models between local governments and the central government,this study simulates and calculates the degree of revenue imbalance under different scenarios and attempts to propose policy *** results indicate that implementing the destination principle will reduce regional tax ***,adjusting the allocation ratio between the central government and local governments based on city levels is advantageous for further reducing regional tax revenue disparities.

关键词： value-added tax e-commerce destination principle origin principle

Precipitating thermally reinforcement phase in aluminum alloys for enhanced strength at 400℃

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Journal of Materials Science & Technology 2024年第5期172卷 71-82页

作者： xiang Su Yuan Lei yang chen Hongjie Qu Zhixiang Qi Gong Zheng Xu Liu Henggao xiang Guang chen National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China School of Aviation and Mechanical Engineering Changzhou Institute of TechnologyChangzhou 213032China

Heat-resistant aluminum alloys are widely used in aerospace and automotive fields for manufacturing hot components due to their advantages in lightweight design and energy ***,the high-temperature strength of existing cast aluminum alloys is always limited to about 100 MPa at 350℃due to coarsening and transformation of strengthening ***,we reveal that the yield strength and ultimate tensile strength of the T6 state Al-8.4Cu-2.3Ce-1.0Mn-0.5Ni-0.2Zr alloy at 400◦C increase by 34%and 44%after re-aging at 300℃for 100 h,and its thermal strength exhibits distinguished ad-vantage over traditional heat-resistant aluminum *** enhanced elevated-temperature strength is attributed to the reprecipitation of the Ni-bearing T-Al_(20)Cu_(2)Mn_(3)phase,whose number density increases over one *** significant segregation of Ni,Ce,and Zr elements at the interfaces helps improve the thermal stability of the T *** thermostable T phase effectively strengthens the matrix by in-hibiting dislocation ***,a highly interconnected 3D intermetallic network along the grain boundaries can still remain after long-term re-aging at 300℃,which is conducive to imposing a drag on the grain boundaries at high *** finding offers a viable route for enhancing the elevated-temperature strength of heat-resistant aluminum alloys,which could provide expanded opportunities for higher-temperature applications.

关键词： Aluminum alloys Precipitation Thermally reinforcement phase Re-aging treatment High-temperature strength

Lattice-distorted Pt wrinkled nanoparticles for highly effective hydrogen electrocatalysis

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Nano Research 2024年第5期17卷 3819-3826页

作者： Xue Li xiang Han Zhenrui yang Shun Wang Yun yang Juan Wang Jiadong chen Zhongwei chen Huile Jin Wenzhou Key Lab of Advanced Energy Storage and Conversion Zhejiang Province Key Lab of Leather EngineeringCollege of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325035China Institute of New Materials and Industry Technology College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325035China Department of Chemical Engineering Waterloo Institute for NanotechnologyUniversity of WaterlooWaterlooOntario N2L 3G1Canada

Modulating Pt surfaces through the introduction of lattice distortion emerges as immensely effective strategy that enhances the kinetics of alkaline hydrogen evolution and oxidation *** this study,we fabricated lattice-distorted Pt wrinkled nanoparticles(LD-Pt WNPs)for efficient hydrogen *** LD-Pt WNPs not only outperform the Pt/C benchmark in hydrogen oxidation reaction,achieving an excellent mass-specific current of 968.5 mA·mg_(Pt)^(-1)(9 times that of Pt/C),but also demonstrate outstanding hydrogen evolution reaction activity with a small overpotential of 58.0 *** experiments and density functional theory calculations reveal that lattice defects introduce an abundance of unsaturated coordination atoms while modifying the d-band center of *** dual effect optimizes the binding strength of crucial H and OH intermediates,leading to a significant reduction in the energy barrier of the reaction bottleneck,commonly known as the Volmer *** work unveils a fresh viewpoint on projecting and developing high efficiency electrocatalysts through defect engineering.

关键词： distortion nanoparticle hydrogen evolution reaction defect engineering hydrogen oxidation reaction

Privacy Protection for Blockchain-Based Healthcare IoT Systems: A Survey

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IEEE/CAA Journal of Automatica Sinica 2024年第8期11卷 1757-1776页

作者： Minfeng Qi Ziyuan Wang Qing-Long Han Jun Zhang Shiping chen yang xiang School of Science Computing and Engineering TechnologiesSwinburne University of TechnologyHawthorn3122VictoriaAustralia Faculty of Data Science City University of MacaoMacaoChina CSIRO Data61 SydneyNew South WalesAustralia

To enable precision medicine and remote patient monitoring,internet of healthcare things(IoHT)has gained significant interest as a promising *** the widespread use of IoHT,nonetheless,privacy infringements such as IoHT data leakage have raised serious public *** the other side,blockchain and distributed ledger technologies have demonstrated great potential for enhancing trustworthiness and privacy protection for IoHT *** this survey,a holistic review of existing blockchain-based IoHT systems is conducted to indicate the feasibility of combining blockchain and IoHT in privacy *** addition,various types of privacy challenges in IoHT are identified by examining general data protection regulation(GDPR).More importantly,an associated study of cutting-edge privacy-preserving techniques for the identified IoHT privacy challenges is ***,several challenges in four promising research areas for blockchain-based IoHT systems are pointed out,with the intent of motivating researchers working in these fields to develop possible solutions.

关键词： Blockchain internet of healthcare things(IoHT) privacy-preserving techniques(PPTs).

A process-oriented approach for identifying potential landslides considering time-dependent behaviors beyond geomorphological features

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 961-978页

作者： xiang Sun Guoqing chen Xing yang Zhengxuan Xu Jingxi yang Zhiheng Lin Yunpeng Liu State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu610059China China Railway Eryuan Engineering Group Co.Ltd. Chengdu610031China Power China chengdu Engineering Co.Ltd. Chengdu610072China

Geomorphological features are commonly used to identify potential ***,overemphasis on these features could lead to *** research proposes a process-oriented approach for potential landslide identification that considers time-dependent *** method integrates comprehensive remote sensing and geological analysis to qualitatively assess slope stability,and employs numerical analysis to quantitatively calculate aging ***,a time-dependent stability calculation method for anticlinal slopes is developed and implemented in discrete element software,incorporating time-dependent mechanical and strength reduction *** considering the time-dependent evolution of slopes,this method highlights the importance of both geomorphological features and time-dependent behaviors in landslide *** method has been applied to the Jiarishan slope(JRS)on the Qinghai-Tibet Plateau as a case *** results show that the JRS,despite having landslide geomorphology,is a stable slope,highlighting the risk of misjudgment when relying solely on geomorphological *** work provides insights into the geomorphological characterization and evolution history of the JRS and offers valuable guidance for studying slopes with similar landslide ***,the process-oriented method incorporating timedependent evolution provides a means to evaluate potential landslides,reducing misjudgment due to excessive reliance on geomorphological features.

关键词： Geomorphological features Evolution history Time-dependent stability calculation Landslides identification Qinghai-Tibet Plateau

Unveiling the chemistry behind the electrolytic production of hydrogen peroxide by oxygenated carbon

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Journal of Energy Chemistry 2024年第9期96卷 49-58页

作者： Pan xiang Kunshang yang Qihao yang yang Gao Wenwen Xu Zhiyi Lu Liang chen Zhiming Wang Ziqi Tian Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054SichuanChina Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201ZhejiangChina Institute for Advanced Study Chengdu UniversityChengdu 610106SichuanChina

Oxygenated carbon materials exhibit outstanding electrocatalytic performance in the production of hydrogen peroxide(H2O2)through a two-electron oxygen reduction *** nature of the active functional group and underlying reaction mechanism,however,remain ***,a comprehensive workflow was established to identify the active sites from the numerous possible *** common hydroxyl group at the notched edge demonstrates a key role in the two-electron *** local chemical environment weakens the binding of OOH intermediate to substrate while enhancing interaction with solution,thereby promoting the H_(2)O_(2)*** increasing pH,the intramolecular hydrogen bond between OOH intermediate and hydroxyl decreases,facilitating OOH ***,the rise in selectivity with increasing potential stems from the suppression of the four-electron *** active site was further validated through *** by theoretical understanding,optimal performance was achieved with high selectivity(>95%)and current density(2.06 mA/cm^(2))in experiment.

关键词： First-principles calculation Oxygen reductionreaction Hydrogen peroxide production Fixed-potential method Oxygenated carbon materials