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Flight Time Minimization of UAV for Cooperative Data Collection in Probabilistic LoS Channel

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China Communications 2024年第2期21卷 210-226页

作者： Yan Li Shaoyi Xu Yunpu Wu Dongji Li School of electronic and Information engineering Beijing Jiaotong UniversityBeijing 100044China School of Electrical engineering and electronic Information Xihua UniversityChengdu 610039China

This paper investigates the data collection in an unmanned aerial vehicle(UAV)-aided Internet of Things(IoT) network, where a UAV is dispatched to collect data from ground sensors in a practical and accurate probabilistic line-of-sight(LoS) channel. Especially, access points(APs) are introduced to collect data from some sensors in the unlicensed band to improve data collection efficiency. We formulate a mixed-integer non-convex optimization problem to minimize the UAV flight time by jointly designing the UAV 3D trajectory and sensors’ scheduling, while ensuring the required amount of data can be collected under the limited UAV energy. To solve this nonconvex problem, we recast the objective problem into a tractable form. Then, the problem is further divided into several sub-problems to solve iteratively, and the successive convex approximation(SCA) scheme is applied to solve each non-convex subproblem. Finally,the bisection search is adopted to speed up the searching for the minimum UAV flight time. Simulation results verify that the UAV flight time can be shortened by the proposed method effectively.

关键词： data collection flight time probabilistic line-of-sight channel unlicensed band unmanned aerial vehicle

Significantly Improved High-Temperature Energy Storage Performance of BOPP Films by Coating Nanoscale Inorganic Layer

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Energy & Environmental Materials 2024年第2期7卷 30-38页

作者： Tiandong Zhang Hainan Yu Young Hoon Jung Changhai Zhang Yu Feng Qingguo Chen Keon Jae Lee Qingguo Chi School of Electrical and electronic engineering Harbin University of Science and TechnologyHarbin 150080China department of Materials Science and engineering Korea Advanced Institute of Science and TechnologyDaejeon 350701Korea

Biaxially oriented polypropylene(BOPP)is one of the most commonly used commercial capacitor films,but its upper operating temperature is below 105℃due to the sharply increased electrical conduction loss at high *** this study,growing an inorganic nanoscale coating layer onto the BOPP film's surface is proposed to suppress electrical conduction loss at high temperature,as well as increase its upper operating *** kinds of inorganic coating layers that have different energy band structure and dielectric property are grown onto the both surface of BOPP films,*** effect of inorganic coating layer on the high-temperature energy storage performance has been systematically *** favorable coating layer materials and appropriate thickness enable the BOPP films to have a significant improvement in high-temperature energy storage ***,when the aluminum nitride(AIN)acts as a coating layer,the AIN-BOPP-AIN sandwich-structured films possess a discharged energy density of 1.5 J cm^(-3)with an efficiency of 90%at 125℃,accompanying an outstandingly cyclic *** the discharged energy density and operation temperature are significantly enhanced,indicating that this efficient and facile method provides an important reference to improve the high-temperature energy storage performance of polymer-based dielectric films.

关键词： coating layer energy storage interfacial barrier polymer films

Deep unfolding based channel estimation for wideband terahertz near-field massive MIMO systems

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Frontiers of Information Technology & electronic engineering 2024年第8期25卷 1162-1172页

作者： Jiabao GAO Xiaoming CHEN Geoffrey Ye LI College of Information Science and electronic engineering Zhejiang UniversityHangzhou 310027China department of Electrical and electronic engineering Imperial College LondonLondon SW 2BUUK

The combination of terahertz and massive multiple-input multiple-output(MIMO)is promising for meeting the increasing data rate demand of future wireless communication systems thanks to the significant band-width and spatial degrees of ***,unique channel features,such as the near-field beam split effect,make channel estimation particularly challenging in terahertz massive MIMO *** one hand,adopting the conventional angular domain transformation dictionary designed for low-frequency far-feld channels will result in degraded channel sparsity and destroyed sparsity structure in the transformed *** the other hand,most existing compressive sensing based channel estimation algorithms cannot achieve high performance and low complexity *** alleviate these issues,in this study,we first adopt frequency-dependent near-field dictionaries to maintain good channel sparsity and sparsity structure in the transformed domain under the near-field beam split ***,a deep unfolding based wideband terahertz massive MIMO channel estimation algorithm is *** each iteration of the approximate message passing-sparse Bayesian learning algorithm,the optimal update rule is learned by a deep neural network(DNN),whose architecture is customized to effectively exploit the inherent channel ***,a mixed training method based on novel designs of the DNN architecture and the loss function is developed to effectively train data from different system *** results validate the superiority of the proposed algorithm in terms of performance,complexity,and robustness.

关键词： Terahertz Massive MIMO Channel estimation Deep learning

The Combined Effect of Spin-Transfer Torque and Voltage-Controlled Strain Gradient on Magnetic Domain-Wall Dynamics:Toward Tunable Spintronic Neuron

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Chinese Physics Letters 2024年第5期41卷 120-137页

作者：郁国良何鑫岩施胜宾邱阳朱明敏王嘉维李燕李元勋王杰周浩淼 College of Information engineering China Jiliang UniversityHangzhou 310018China The Key Laboratory of Electromagnetic Wave Information Technology and Metrology of Zhejiang Province Hangzhou 310018China department of engineering Mechanics Zhejiang UniversityHangzhou 310027China School of electronic Science and engineering University of Electronic Science and Technology of ChinaChengdu 611731China

Magnetic domain wall(DW), as one of the promising information carriers in spintronic devices, have been widely investigated owing to its nonlinear dynamics and tunable properties. Here, we theoretically and numerically demonstrate the DW dynamics driven by the synergistic interaction between current-induced spin-transfer torque(STT) and voltage-controlled strain gradient(VCSG) in multiferroic heterostructures. Through electromechanical and micromagnetic simulations, we show that a desirable strain gradient can be created and it further modulates the equilibrium position and velocity of the current-driven DW motion. Meanwhile, an analytical Thiele's model is developed to describe the steady motion of DW and the analytical results are quite consistent with the simulation data. Finally, we find that this combination effect can be leveraged to design DW-based biological neurons where the synergistic interaction between STT and VCSG-driven DW motion as integrating and leaking motivates mimicking leaky-integrate-and-fire(LIF) and self-reset function. Importantly, the firing response of the LIF neuron can be efficiently modulated, facilitating the exploration of tunable activation function generators, which can further help improve the computational capability of the neuromorphic system.

关键词： tunable synergistic integrating

Formal Modeling of Frame Selection in Asynchronous TSN Communications

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Chinese Journal of electronics 2024年第2期33卷 549-563页

作者： Ershuai LI Xuan ZHOU Jinjing SUN Huagang XIONG Feng HE School of electronic and Information engineering Beihang University

The asynchronous time-sensitive networking(TSN) based on IEEE 802.1Qcr is expected to be a promising solution for the asynchronous transmissions of safety-critical flows without the support of clock *** the asynchronous traffic shaping(ATS) mechanism is adopted to meet the deadline requirements for transmissions of safety-critical flow, it is necessary to formally verify the real-time properties and corresponding network ***, it is still unclear how to build an efficient formal model to evaluate different frame selection methods during the ATS scheduling process, which originate from the dominations of priority or eligibility time. In this paper, we present a formal modeling framework to compare the impacts of different frame selection on transmission sequence under the ATS mechanism. According to the priority level(p ATS) or eligibility time(e ATS) for flows, two transmission selection methods in ATS are modeled and compared. Then, we verify the real-time properties of ATS. The result shows that the shaping-for-free property can be satisfied with the p ATS method but can not be fulfilled with the e ATS method. Besides, the timing analysis results illustrate that the e ATS method can provide more fairness than the p ATS method for the transmission of low-priority flows in TSN networks.

关键词： System recovery Real-time systems Delays Synchronization

Wavelength-interval switchable Brillouin–Raman random fiber laser through Brillouin pump manipulation

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Chinese Physics B 2024年第7期33卷 374-379页

作者：李阳徐恩明陈睿佳 Yu-Gang Shee 张祖兴 Advanced Photonic Technology Laboratory College of Electronic and Optical Engineering&College of MicroelectronicsNanjing University of Posts and TelecommunicationsNanjing 210023China department of Electrical and electronic engineering Lee Kong Chian Faculty of Engineering&Science(LKC FES)Universiti Tunku Abdul Rahman(UTAR)Sungai Long CampusMalaysia

A wavelength-interval switchable Brillouin–Raman random fiber laser(BRRFL) based on Brillouin pump(BP) manipulation is proposed in this paper. The proposed wavelength-interval switchable BRRFL has a full-open cavity configuration, featuring multiwavelength output with wavelength interval of double Brillouin frequency shifts. Through simultaneously injecting the BP light and its first-order stimulated Brillouin-scattered light into the cavity, the laser output exhibits a wavelength interval of single Brillouin frequency shift. The wavelength-interval switching effect can be manipulated by controlling the power of the first-order stimulated Brillouin scattering light. The experimental results show the multiwavelength output can be switched between double Brillouin frequency shift multiwavelength emission with a broad bandwidth of approximately 60 nm and single Brillouin frequency shift multiwavelength emission of 44 nm. The flexible optically controlled random fiber laser with switchable wavelength interval makes it useful for a wide range of applications and holds significant potential in the field of wavelength-division multiplexing optical communication.

关键词： wavelength-interval switchable fiber laser Brillouin fiber laser stimulated Brillouin-scattered random fiber laser

Effect of Blood Circulation in Veins on Resonance Suppression of the Dragonfly Wing Constructed by Numerical Method

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Journal of Bionic engineering 2024年第2期21卷 877-891页

作者： Lijun Zhang Xu Zhang Kaifei Wang Zhenwei Gan Shibo Liu Xiao Liu Zhengjun Jing Xudong Cui Jiahui Lu Jing Liu College of Mechanical and electronic engineering China University of PetroleumQingdao266580China

To reveal the resonance suppression mechanism of the blood circulation in dragonfly wings,a numerical modeling method of dragonfly wings based on Voronoi diagrams is proposed,and the changes in mass,aerodynamic damping,and natural frequencies caused by blood circulation in veins are *** equivalent mass of blood,boundary conditions,and aerodynamic damping are calculated *** analysis and harmonic response analysis of wing models with different blood circulation paths are performed using the finite-element method(FEM).The vibration reduction ratioδis introduced to compare the damping efficiency of different mass ***,a natural frequency testing device is constructed to measure the natural frequencies of dragonfly *** results indicate that the shape,mass,and natural frequencies of the dragonfly wing model constructed by numerical method agree well with *** mass distribution on the wing can be altered by blood circulation,thereby adjusting the natural frequencies and achieving resonance *** highestδof 1.013 is observed in the C region when blood circulates solely in secondary veins,but it is still lower than theδof 1.017 when blood circulates in complete *** aerodynamic damping ratio(1.19–1.79%)should not be neglected in the vibration analysis of the beating wing.

关键词： Dragonfly wings Blood circulation Resonance suppression Voronoi diagram FEM

Emerging direct current triboelectric nanogenerator for high-entropy mechanical energy harvesting

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Science China(Technological Sciences) 2024年第5期67卷 1297-1316页

作者： CHEN Jie GUO RuiLong GUO HengYu College of Physics and electronic engineering Chongqing Normal UniversityChongqing 401331China department of Applied Physics Chongqing UniversityChongqing 401331China

In the era of the Internet of Things(IoT),the provision of sustainable power to distributed,mobile,and low-power-consumption electronic devices is a critical *** overcome this challenge,the triboelectric nanogenerator(TENG),a highly efficient high-entropy mechanical energy harvesting device,was developed in *** device enables the direct conversion of irregular and low-frequency mechanical energy into pulsed alternating current(AC)***,the incompatibility of most electronic devices with AC signals necessitates rectifier circuits or generators that deliver direct current(DC)*** recent years,DC-TENGs have undergone extensive development,achieving significant milestones in various application fields while also facing crucial challenges that require *** this review,three categories of DC-TENG devices with distinct operating mechanisms are comprehensively explored:multiphase coupling,mechanical rectification,and air *** typical structures and working mechanisms are thoroughly discussed,and specific output performance limitations,along with corresponding optimization strategies,are ***,the applications of DC-TENGs in various scenarios are ***,the challenges faced by DC-TENGs and potential solutions are analyzed to guide further advancements in this technology.

关键词： TENG direct current working mechanisms output performance limitations optimization strategies

Broadband intelligent programmable metasurface with polarization-modulated self-adaptive electromagnetic functionality switching

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Photonics Research 2024年第7期12卷 1395-1409页

作者： XIMING LI RUI XU XIAOFENG SUN YUAN ZHAO ZHAO YANG GUOHONG DU College of electronic engineering Chengdu University of Information TechnologyChengdu 610225China

Programmable metasurfaces have received a great deal of attention due to their ability to dynamically manipulate electromagnetic(EM) waves. Despite the rapid growth, most of the existing metasurfaces require manual control to switch among different functionalities, which poses severe limitations on practical applications. Here, we put forth an intelligent metasurface that has self-adaptive EM functionality switching in broadband without human participation. It is equipped with polarization discrimination antennas(PDAs) and feedback components to automatically adjust functionalities for the different incident polarization information.

关键词： equipped adjust polarization