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Joint Optimization of Power Allocation and Beamforming for UAV-RIS Communication System

IEEE Wireless Communications Letters 2025年

作者： Guo, Xinying Liu, Longfei Zhang, Jiankang Chen, Sheng Ministry of Education Key Laboratory of Grain Information Processing and Control Henan University of Technology China Henan University of Technology College of Information Science and Engineering Zhengzhou450001 China Bournemouth University Department of Computing and Informatics BH12 5BB United Kingdom University of Southampton School of Electronics and Computer Science SouthamptonSO17 1BJ United Kingdom

This paper considers the communication system assisted by a fixed-trajectory unmanned aerial vehicle (UAV), which is equipped with a reconfigurable intelligent surface (RIS). For this UAV-RIS assisted system, we jointly optimize the power allocation and active beamforming at the base station (BS) and the passive beamforming at the RIS, by a novel phase block coordinate descent algorithm framework aimed at maximizing the system sum-rate. Specifically, the joint optimization problem is decomposed into two phases, and we propose two optimization algorithms: one for BS power allocation using fractional programming (FP) and the other for jointly optimizing active and passive beamforming using FP-manifold, which alternately optimize two phases. Simulation results not only highlight the rapid convergence and evident superiority of our proposed framework but also reveal that the optimal UAV-RIS placement is related to the flight height. © 2012 IEEE.

关键词： Unmanned aerial vehicles (UAV)

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Observation of Copropagating Chiral Zero Modes in Magnetic Photonic Crystals

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Physical Review Letters 2025年第3期134卷 033802-033802页

作者： Zhongfu Li Shaojie Ma Shuwei Li Oubo You Yachao Liu Qingdong Yang Yuanjiang Xiang Peiheng Zhou Shuang Zhang New Cornerstone Science Laboratory Department of Physics The University of Hong Kong Hong Kong 999077 China Shanghai Engineering Research Centre of Ultra Precision Optical Manufacturing Department of Optical Science and Engineering School of Information Science and Technology Fudan University Shanghai 200433 China National Engineering Research Center of Electromagnetic Radiation Control Materials Key Laboratory of Multi-spectral Absorbing Materials and Structures of Ministry of Education University of Electronic Science and Technology of China Chengdu China College of Electronics and Information Engineering Shenzhen University 518060 Shenzhen China School of Physics and Electronics Hunan University Changsha 410082 China Materials Innovation Institute for Life Sciences and Energy (MILES) HKU-SIRI 518000 Shenzhen China

Topological singularities, such as Weyl points (WPs) and Dirac points, can give rise to unidirectional propagation channels known as chiral zero modes (CZMs) when subject to a magnetic field. CZMs, as distinct zeroth Landau levels (bulk modes) with high degeneracy, are responsible for intriguing phenomena like the chiral anomaly in quantum systems. The propagation direction of each CZM is determined by both the applied magnetic field and the topological charge of the singularity point. While counterpropagating CZMs have been observed in 2D and 3D systems, the realization of copropagating CZMs has remained elusive. Here, we present the first experimental observation of copropagating CZMs in magnetic photonic crystals hosting a single pair of ideal Weyl points. By manipulating the crystal’s structural configuration and applying a uniform bias magnetic field, we spatially alter the locations of the WPs, creating pseudo-magnetic fields of opposite directions for different WPs. This arrangement results in a pair of CZMs that possess the same group velocity and copropagate. Our work opens up new possibilities for the topological manipulation of wave propagation and may lead to advancements in optical waveguides, switches, and various other applications.

关键词： Wave propagation

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The Impacts of Climate Change on the Environment and Human Health in China:A Call for more Ambitious Action

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Biomedical and Environmental Sciences 2025年第2期38卷 127-143页

作者： Shilu Tong Yu Wang Yonglong Lu Cunde Xiao Qiyong Liu Qi Zhao Cunrui Huang Jiayu Xu Ning Kang Tong Zhu Dahe Qin Ying Xu Buda Su Xiaoming Shi National Institute of Environmental Health Chinese Center for Disease Control and PreventionBeijing 100021China School of Public Health and Social Work Queensland University of TechnologyBrisbane 4001Australia State Key Laboratory of Marine Environmental Science and International Institute for Sustainability Science College of the Environment and EcologyXiamen UniversityXiamen 361102FujianChina State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing 100875China National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases National Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and PreventionBeijing 102206China School of Public Health Shandong UniversityJinan 250012ShandongChina Vanke School of Public Health Tsinghua UniversityBeijing 100084China Institute of Reproductive and Child Health/National Health Commission Key Laboratory of Reproductive Health and Department of Epidemiology and Biostatistics/Ministryof Education Key Laboratory of Epidemiology of Major Diseases(PKU) School of Public HealthPeking University Health Science CentreBeijing 100191China SKL-ESPC&SEPKL-AERM Department of Environmental HealthCollege of Environmental Sciences and Engineering&Center for Environment and HealthPeking UniversityBeijing 100871China China Meteorological Administration Beijing 100081China National Climate Centre China Meteorological AdministrationBeijing 100081China Nanjing University of Information Science and Technology Nanjing 210044JiangsuChina Chinese Center for Disease Control and Prevention Beijing 102206China

As global greenhouse gases continue rising,the urgency of more ambitious action is clearer than ever *** is the world’s biggest emitter of greenhouse gases and one of the countries affected most by climate *** evidence about the impacts of climate change on the environment and human health may encourage China to take more decisive action to mitigate greenhouse gas emissions and adapt to climate impacts.

关键词： change greenhouse climate

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From Spent Lithium-Ion Batteries to Femn2o4-Rgo for Advanced Li-Co2 Batteries: Case of Comprehensive Utilization of Spent Cathodes and Anodes

SSRN

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SSRN 2025年

作者： Deng, Qinghua He, Bin Zhang, Shi Li, Xuguang Chen, Dan Wang, Tianyu School of Material Engineering Wuhu Institute of Technology Wuhu241002 China Huzhou Key Laboratory of Environmental Functional Materials and Pollution Control Department of Materials Chemistry Huzhou University Huzhou313000 China Key Laboratory of Environmental Remediation and Ecological Health Ministry of Industry and Information Technology School of Environmental and Biological Engineering Nanjing University of Science and Technology Nanjing210094 China

The upcoming massive lithium ferromanganese phosphate batteries (LMFP) utilization suggests a huge spent LMFP in near future. Improper disposal not only cause waste of valuable materials in spent LMFP, but also raise the risk of environmental pollution. Meanwhile, exploitation of efficient catalytic cathode holds the key to the commercialization of Li-CO2 batteries, a high energy density next-generation energy storage device. This work describes an integrated functionalization pathway of spent LMFP by converting Fe/Mn in spent cathode to FeMn2O4 nanoparticles and immobilizing them on spent anode-derived reduced graphene oxide (rGO) for advanced Li-CO2 batteries cathodes. The electronic structure of the Fe/Mn bimetallic interface facilitates the adsorption and activation of CO2 as well as the decomposition of discharged products. In addition, the highly conductive rGO realizes the interface resistance suppression and the output power enhancement. Benefiting from the reliable treatment processes of spent LMFP and the rational design of FeMn2O4-rGO, the assembled Li-CO2 batteries exhibited favorable discharge capacity of 12810 mAh g-1, operating voltage of 2.71 V, and cycling performance of >200 cycles at rate of 100 mA g-1. Moreover, the electrochemical mechanism is further investigated by density functional theory calculations coupled with experimental tests. This work provides new pathway for the comprehensive utilization of spent cathodes and anodes of LMFP and the exploitation of advanced Li-CO2 batteries cathode. © 2025, The Authors. All rights reserved.

关键词： Anodes

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Design and Testing of a Direct Oil Cooled Homopolar Synchronous Generator with Dual DC-Link via Diode Rectifiers

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IEEE Transactions on Transportation Electrification 2025年

作者： Vannini, Amedeo Nardo, Mauro Di Rocca, Antonino La Riccio, Jacopo Korman, Oguz Rocca, Salvatore La Marfoli, Alessandro Gerada, Chris University of Nottingham Power Electronics Machines and Control Research Institute NottinghamNG7 2GT United Kingdom Politecnico di Bari Department of Electrical Engineering and Information Technology Bari70126 Italy ARQUIMEA Research Center Santa Cruz de Tenerife Spain

The drivetrains of large transportation systems, such as aircraft or ships, are evolving towards hybrid configurations with DC primary power distribution thanks to their higher efficiency. In this context, synchronous homopolar machines equipped with diode rectifiers are promising solutions for on-board generation units as they eliminate the need for active power electronic converters. In this paper, a synchronous homopolar generator with a dual DC-link configuration, where each power bus is supplied via two series-connected rectifiers, is designed and tested. A direct oil-cooled excitation coil provides the full voltage-control capability of the two independent DC links. The manuscript addresses the challenge of the analytical electromagnetic sizing of this machine topology, which has an intrinsic three-dimensional magnetic behaviour. The electromagnetic design is validated through a 3D-FE analysis, while the thermal sizing of the solenoid hollow oil-cooled excitation coil is analytically carried out and validated through CFD analysis. A 1.2 kW, 6000 rpm proof-of-concept demonstrator has been built and tested, and the reported measurements match the predicted electromagnetic and thermal operation. Although the experimental validation is performed on a small-scale prototype, this work may provide a foundation for designing an active power electronic-free electric generation unit for future large transportation systems. © 2015 IEEE.

关键词： Electromagnetic propulsion

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Enhanced Security Through Honeywords and Video CAPTCHA: An Innovative Authentication and Tracking Mechanism

Enhanced Security Through Honeywords and Video CAPTCHA: An I...

引用

Advances in Electrical, Computing, Communication and Sustainable Technologies (ICAECT), International Conference on

作者： Madhuri Gurale Komal Borate Rachana R. Sangitrao Garima Tiwari Information Technology Department D. Y. Patil College of Engineering Akurdi Pune India Artifical Intelligency and Data Science Department D. Y. Patil College of Engineering Akurdi Pune India Department of Instrumentation and Control D. Y. Patil College of Engineering Akurdi Pune India Department of Electronics & Communication D. Y. Patil College of Engineering Akurdi Pune India

ISBN: (数字)9798350356236

ISBN: (纸本)9798350356243

In recent years, activities across countries have increasingly been carried out digitally, with information being shared over networks to boost speed and efficiency. However, this digital transformation poses security threats. Cybercrime has consistently evolved, necessitating improved network security measures to combat digital scams. To maintain security, users are assigned unique identification passwords, which they are instructed to keep secret. Despite this, attackers often manage to steal passwords. To counter these threats, we propose using honeywords, which are decoy passwords created from the existing user password. If an attacker inputs a honeyword, an alert is activated for the administrator. Moreover, we implement IP and location monitoring for users and introduce a approach known as the video click-based CAPTCHA system. This scheme authenticates users by distinguishing between humans and bots, addressing issues in traditional graphic password CAPTCHA schemes. This architecture significantly enhances protection and security of data and applications over online networks.

关键词： Resistance Authentication Passwords Network security Reliability Protection Computer crime Usability Monitoring CAPTCHAs

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Photonic axion insulator

引用

Science (New York, N.Y.) 2025年第6730期387卷 162-166页

作者： Liu, Gui-Geng Mandal, Subhaskar Xi, Xiang Wang, Qiang Devescovi, Chiara Morales-Pérez, Antonio Wang, Ziyao Yang, Linyun Banerjee, Rimi Long, Yang Meng, Yan Zhou, Peiheng Gao, Zhen Chong, Yidong García-Etxarri, Aitzol Vergniory, Maia G. Zhang, Baile Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore Research Center for Industries of the Future Department of Electronic and Information Engineering School of Engineering Westlake University Hangzhou China School of Electrical Engineering and Intelligentization Dongguan University of Technology Dongguan China National Laboratory of Solid State Microstructures School of Physics Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing China Donostia International Physics Center Donostia-San Sebastian Spain Institute for Theoretical Physics ETH Zurich Zurich Switzerland Material and Applied Physics Department University of the Basque Country (UPV/EHU) Donostia-San Sebastián Spain Department of Electronic and Electrical Engineering Southern University of Science and Technology Shenzhen China National Engineering Research Center of Electromagnetic Radiation Control Materials Key Laboratory of Multi-spectral Absorbing Materials and Structures of Ministry of Education University of Electronic Science and Technology of China Chengdu China State Key Laboratory of Optical Fiber and Cable Manufacture Technology Department of Electronic and Electrical Engineering Guangdong Key Laboratory of Integrated Optoelectronics Intellisense Southern University of Science and Technology Shenzhen China Centre for Disruptive Photonic Technologies Photonics Institute Nanyang Technological University Singapore IKERBASQUE Basque Foundation for Science Bilbao Spain Max Planck Institute for Chemical Physics of Solids Dresden Germany Département de Physique et Institut Quantique Université de Sherbrooke Sherbrooke Canada

Axions, hypothetical elementary particles that remain undetectable in nature, can arise as quasiparticles in three-dimensional crystals known as axion insulators. Previous implementations of axion insulators have largely been limited to two-dimensional systems, leaving their topological properties in three dimensions unexplored in experiment. Here, we realize an axion insulator in a three-dimensional photonic crystal and probe its topological properties. Demonstrated features include half-quantized Chern numbers on each surface that resembles a fractional Chern insulator, unidirectional chiral hinge states forming topological transport in three dimensions, and arithmetic operations between fractional and integer Chern numbers. Our work experimentally establishes the axion insulator as a three-dimensional topological phase of matter and enables chiral states to form complex, unidirectional three-dimensional networks through braiding.

关键词：

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Enhanced Security Through Honeywords and Video CAPTCHA: An Innovative Authentication and Tracking Mechanism 5

Enhanced Security Through Honeywords and Video CAPTCHA: An I...

引用

5th IEEE International Conference on Advances in Electrical, Computing, Communication and Sustainable Technologies, ICAECT 2025

作者： Gurale, Madhuri Borate, Komal Sangitrao, Rachana R. Tiwari, Garima D. Y. Patil College of Engineering Information Technology Department Akurdi Pune412101 India D. Y. Patil College of Engineering Artifical Intelligency and Data Science Department Akurdi Pune412101 India D. Y. Patil College of Engineering Department of Instrumentation and Control Akurdi Pune412101 India D. Y. Patil College of Engineering Department of Electronics & Communication Akurdi Pune412101 India

ISBN: (纸本)9798350356236

关键词： Malware

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High-temperature current conduction through three kinds of Schottky diodes

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Chinese Physics B 2009年第11期18卷 5029-5033页

作者：李菲张小玲段毅谢雪松吕长志 Department of Electronic Information and Control Engineering Beijing University of Technology

Fundamentals of the Schottky contacts and the high-temperature current conduction through three kinds of Schottky diodes are studied. N-Si Schottky diodes, GaN Schottky diodes and AlGaN/GaN Schottky diodes are investigated by I-V-T measurements ranging from 300 to 523 K. For these Schottky diodes, a rise in temperature is accompanied with an increase in barrier height and a reduction in ideality factor. Mechanisms are suggested, including thermionic emission, field emission, trap-assisted tunnelling and so on. The most remarkable finding in the present paper is that these three kinds of Schottky diodes are revealed to have different behaviours of high-temperature reverse currents. For the n-Si Schottky diode, a rise in temperature is accompanied by an increase in reverse current. The reverse current of the GaN Schottky diode decreases first and then increases with rising temperature. The AlGaN/GaN Schottky diode has a trend opposite to that of the GaN Schottky diode, and the dominant mechanisms are the effects of the piezoelectric polarization field and variation of two-dimensional electron gas charge density.

关键词： Schottky diodes Schottky barrier height ideality factor reverse current

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Characteristic and Mechanism of Pressure Fluctuation Caused by Self-Induced Oscillation of Supersonic Impinging Jet

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Journal of Thermal Science 2013年第2期22卷 123-127页

作者： Tsuyoshi Yasunobu Yumiko Otobe Hideo Kashimura Department of Control & Information Systems Engineering Kitakyushu College of Technology

When the underexpanded supersonic jet impinges on the obstacle, it is well known that the self-induced flow os- cillation occurs. This oscillation depends on the pressure ratio in the flowfield, the position of an obstacle and is related with the noise problems of aeronautical and other industrial engineering. The characteristic and the mechanism of self-induced flow oscillation, have to be clarified to control various noise problems. But, it seems that the characteristics of the oscillated flowfield and the mechanism of an oscillation have to be more cleared to control the oscillation. This paper aims to clarify the effect of the pressure ratio and the obstacle position and the mechanism of self-induced flow oscillation by numerical analysis and experiment, when the underexpanded su- personic jet impinges on the cylindrical body. From the result of this study, it is clear that occurrence of the self-induced flow osciUation depends on the pressure balance in the flowfield.

关键词： Supersonic Jet Mach Disk Barrel Shock Flow Oscillation Flow Visualization Numerical Analysis

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