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Energy & Environmental Materials 2024年第4期7卷 396-403页

作者： Myeong-Hyeon Kim Sang-Joon Park Tae-Jun Ha department of {1. Materials engineering Kwangwoon University

In this study,wearable triboelectric nanogenerators comprising bar-printed polyvinylidene fluoride (PVDF) films incorporated with cobalt-based metalorganic framework (Co-MOF) were *** enhanced output performance of the TENCs was attributed to the phase transition of PVDF from α-crystals to β-crystals,as facilitated by the incorporation of the MOF.

关键词： bar printing phase transition polyvinylidene fluoride incorporated with cobalt-based metal–organic framework self-powered mobile electronics wearable triboelectric nanogenerators

Watt-level acousto-optically Q-switched Pr:YLF laser at 639 nm

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Chinese Optics Letters 2024年第1期22卷 76-83页

作者：薛喻宸张瑞松戴征东王中玉许惠英蔡志平 department of {1. engineering School of Electronic Science and Engineering(National Model Microelectronics College)Xiamen UniversityXiamen 361005China

We present a study on a watt-level acousto-optically Q-switched Pr:YLF laser at three different repetition rates(1. kHz,20 kHz,and 50 kHz)for the first time,to the best of our *** corresponding average output powers and pulse widths were measured to be 1.1. W,1.2 W,and 1.32 W,and 40 ns,52 ns,and 80 ns,respectively.A maximum pulse energy of0.1. mJ was obtained,corresponding to a peak power of up to 2.8 kW at a repetition rate of 1. *** simulated dynamics of a fast Q-switched Pr:YLF laser is in agreement with the *** laser's ability to generate stable pulses with high peak power and short pulse width makes it highly desirable for various practical applications,such as laser machining and material processing.

关键词： red pulsed laser Pr:YLF diode pump acousto-optical Q switching

Monolithic integrated optoelectronic chip for vector force detection

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Microsystems & Nanoengineering 2024年第3期10卷 245-257页

作者： Jiansong Feng Zhongqi Wang Mengyuan Zhanghu Xu Zhang Yong Shen Jing Yang Zhibin Li Bin Chen Taihong Wang Xiaolong Chen Zhaojun Liu department of Electrical and {1. engineering Southern University of Science and TechnologyShenzhen 518055China department of Electrical and {1. engineering The University of Hong KongHong KongChina

Sensors with a small footprint and real-time detection capabilities are crucial in robotic surgery and smart wearable *** device footprint while maintaining its high performance is a major challenge and a significant limitation to their ***,we proposed a monolithic integrated micro-scale sensor,which can be used for vector force *** sensor combines an optical source,four photodetectors,and a hemispherical silicone elastomer component on the same sapphire-based AlGaInP *** chip-scale optical coupling is achieved by employing the laser lift-off techniques and the flip-chip bonding to a processed sapphire *** hemispherical structure device can detect normal and shear forces as low as 1.N within a measurement range of 0–220 mN for normal force and 0–1. mN for shear *** packaging,the sensor is capable of detecting forces over a broader range,with measurement capabilities extending up to 1. N for normal forces and 0.2 N for shear *** has an accuracy of detecting a minimum normal force of 25 mN and a minimum shear force of 20 ***,this sensor has been validated to have a compact footprint of approximately 1.5 mm^(2),while maintaining high real-time *** also demonstrate its promising potential by combining this sensor with fine surface texture perception in the fields of compact medical robot interaction and wearable devices.

关键词： robot force smart

Statistical analysis and interpretation on lightning impulse breakdown voltages of ester liquids under varying field uniformity

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High Voltage 2024年第1期9卷 22-34页

作者： Haichuan Yu Qiang Liu Zhongdong Wang department of Electrical and {1. engineering The University of ManchesterManchesterUK department of {1. University of ExeterExeterUK

Ester liquids(ELs),as the alternative transformer liquids to the conventional mineral oils(MOs),have been increasingly used in power transformers with high voltage *** various properties,the lightning impulse breakdown voltages(LIBDVs)have been studied elaborately in the past two decades under different electric field *** electric field uniformities do have an effect on the breakdown characteristics,for example,breakdown mechanisms,polarity effects,and differences of LIBDV between ELs and MOs,which is quantitatively investigated based on the LIBDVs collected from the *** breakdown mechanism transition phenomenon between streamer initiation dominated breakdown and streamer propagation dominated breakdown has been reviewed ***,the transition field factor boundaries to observe the polarity effect on LIBDVs are taken at around 20 for ELs and 1. for ***,the transition field factor boundaries to observe the LIBDV distinctions between ELs and MOs are about 1.9 and 1. under positive and negative lightning impulse,*** systematic analysis and interpretation on the transition field factor boundaries among different phenomena can provide insights on insulation design of ELs filled power transformers.

关键词： field lightning breakdown

A Joint Activity and Data Detection Scheme for Asynchronous Grant-Free Rateless Multiple Access

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China Communications 2024年第1期21卷 34-52页

作者： Wei Zhang Xiaofeng Zhong Shidong Zhou department of {1. engineering Tsinghua UniversityBeijing 100084China

This paper considers the frameasynchronous grant-free rateless multiple access(FAGF-RMA)scenario,where users can initiate access at any symbol time,using shared channel resources to transmit data to the base *** coding is introduced to enhance the reliability of the *** literature has shown that FA-GFRMA can achieve lower access delay than framesynchronous grant-free rateless multiple access(FSGF-RMA),with extreme reliability enabled by rateless *** support FA-GF-RMA in more practical scenarios,a joint activity and data detection(JADD)scheme is *** the feature of sporadic traffic,approximate message passing(AMP)is exploited for transmission signal matrix ***,to determine the packet start points,a maximum posterior probability(MAP)estimation problem is solved based on the recovered transmitted signals,leveraging the intrinsic power pattern in the *** iterative power-pattern-aided AMP algorithm is devised to enhance the estimation performance of *** results verify that the proposed solution achieves a delay performance that is comparable to the performance limit of FA-GF-RMA.

关键词： asynchronous grant-free JADD rateless codes

Integrated bound-state-in-the-continuum photon-pair source

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Photonics Research 2024年第6期12卷 1322-1327页

作者： FAN YE YUE QIN CHENFEI CUI XIANKAI SUN HON KI TSANG department of {1. engineering The Chinese University of Hong KongHong KongChina

Integrated photon-pair sources based on spontaneous parametric down conversion(SPDC)in novel high-χ^((2))materials are used in quantum photonic systems for quantum information processing,quantum metrology,and quantum ***,the need for extensive fabrication process development and optimization of dry-etching processes significantly impedes the rapid exploration of different material platforms for low-loss quantum photonic ***,bound states in the continuum(BICs)have emerged as a promising approach for realizing ultralow-loss integrated photonic circuits without requiring an etching *** realizations of BIC photonic circuits have,however,been limited primarily to the classical ***,we explore the BIC phenomena in the quantum regime and show that the etchless BIC platform is suitable for use in integrated entangled photon-pair sources based on the SPDC process in high-χ^((2))*** lithium niobate as an example,we demonstrate photon-pair generation at telecommunication wavelengths,attaining a maximum internal generation rate of 3.46 MHz,a coincidence-to-accidental ratio of 5773,and an experimental two‐photon interference visibility of 94%.Our results demonstrate that the BIC platform can be used for quantum photonic circuits,and this will enable the rapid exploration of different emergingχ^((2))materials for possible use in integrated quantum photonics in the future.

关键词： process quantum continuum

Temporal and Spatial Optimization for 5G Base Station Groups in Distribution Networks

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1159-1169页

作者： Silu Zhang Nian Liu Jianpei Han department of Electrical and {1. engineering North China Electric Power UniversityBeijingChina

With the large-scale connection of 5G base stations(BSs)to the distribution networks(DNs),5G BSs are utilized as flexible loads to participate in the peak load regulation,where the BSs can be divided into base station groups(BSGs)to real-ize inter-district energy transfer.A Stackelberg game-based opti-mization framework is proposed,where the distribution net-work operator(DNO)works as a leader with dynamic pricing for multi-BSGs;while BSGs serve as followers with the ability of demand response to adjust their charging and discharging strategies in temporal dimension and load migration strategy in spatial ***,the presence and uniqueness of the Stackelberg equilibrium(SE)are ***,differ-ential evolution is adopted to reach the SE and the optimization problem in multi-BSGs is decomposed to solve the time-space ***,through simulation of a practical system,the results show that the DNO operation profit is increased via cut-ting down the peak load and the operation costs for multi-BSGs are reduced,which reaches a win-win effect.

关键词： 5G base station dynamic pricing demand response energy storage load migration Stackelberg game optimization

Few-shot incremental radar target recognition framework based on scattering-topology properties

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Chinese Journal of Aeronautics 2024年第8期37卷 246-260页

作者： Chenxuan LI Weigang ZHU Bakun ZHU Yonggang LI Graduate School Space Engineering UniversityBeijing 101400China department of {1. and Optical engineering Space Engineering UniversityBeijing 101400China

The continuous emergence of new targets in open scenarios leads to a substantial decrease in the performance of Inverse Synthetic Aperture Radar(ISAR)recognition ***,data scarcity further exacerbates the challenge of identifying new classes of ISAR *** this paper,a few-shot incremental target recognition framework based on Scattering-Topology Properties(STPIL)is ***,STPIL extracts scattering-topology properties of ISAR targets as recognition ***,the pseudo-incremental training strategy effectively alleviates the algorithm’s forgetting of old knowledge,and improves compatibility with new ***,a feature embedding network,with few parameters,is designed based on the graph neural *** embedding network is highly adaptable to changes in data ***,STPIL fully considers the joint distribution and marginal distribution in scattering features,and uses the Brownian distance metric module to make the scattering-topology features more *** results on both the simulation dataset and the public measured data indicate that STPIL can effectively balance new classes with old classes,and has superior performance to other advanced methods in the incremental recognition of targets.

关键词： Brownian distance metric Graph neural networks Incremental learning Inverse Synthetic Aperture Radar(ISAR) Scattering

A Review of State-of-the-art Flexible Power Point Tracking Algorithms in Photovoltaic Systems for Grid Support:Classification and Application

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Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 1-21页

作者： Mina Haghighat Mehdi Niroomand Hossein Dehghani Tafti Christopher D.Townsend Tyrone Fernando the department of Electrical {1. University of IsfahanIsfahanIran the department of Electrical Electronic and Computer EngineeringUniversity of Western AustraliaCrawley WA 6009Australia

To maximize conversion efficiency,photovoltaic(PV)systems generally operate in the maximum power point tracking(MPPT)***,due to the increasing penetra tion level of PV systems,there is a need for more developed control functions in terms of frequency support services and voltage control to maintain the reliability and stability of the power ***,flexible active power control is a manda tory task for grid-connected PV systems to meet part of the grid ***,a significant number of flexible pow er point tracking(FPPT)algorithms have been introduced in the existing *** purpose of such algorithms is to real ize a cost-effective method to provide grid support functional ities while minimizing the reliance on energy storage *** paper provides a comprehensive overview of grid support functionalities that can be obtained with the FPPT control of PV systems such as frequency support and volt-var *** of these grid support functionalities necessitates PV sys tems to operate under one of the three control strategies,which can be provided with FPPT *** three control strate gies are classified as:①constant power generation control(CP GC),②power reserve control(PRC),and③power ramp rate control(PRRC).A detailed discussion on available FPPT algo rithms for each control strategy is also *** paper can serve as a comprehensive review of the state-of-the-art FPPT algorithms that can equip PV systems with various grid support functionalities.

关键词： Maximum power point tracking(MPPT) flexi ble power point tracking(FPPT) power reserve control(PRC) power ramp rate control(PRRC) low voltage ride-through(LVRT) constant power generation(CPG)

Near-field wideband beam training for ELAA with uniform circular array

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Science China(Information Sciences) 2024年第6期67卷 370-383页

作者： Yuhao CHEN Linglong DAI department of {1. engineering Tsinghua UniversityBeijing National Research Center for Information Science and Technology (BNRist)

Extremely large-scale antenna array(ELAA) at millimeter wave(mmWave) and Terahertz(THz)band has been considered a key technology for combating high attenuation in high-frequency bands in future6G communications. Uniform circular arrays(UCAs) have attracted much attention because of their ability to provide flat beamforming gain at all angles. To realize efficient beamforming, beam training is widely used to acquire channel state information. However, with a large antenna number, the beam training overhead in ELAA systems becomes overwhelming. Moreover, with a large bandwidth, the beam defocus effect severely degrades beam training accuracy. To address these issues, this paper proposes a frequency-dependent focusing(FDF)-based beam training scheme to realize effective beam training in near-field wideband ELAA systems with UCA. Specifically, we first analyze the FDF property of UCA, where signals at different subcarriers can simultaneously focus on different distances. Then, by exploiting the FDF property to search different distances using different subcarriers simultaneously, we design a hierarchical codebook and propose an FDFbased beam training scheme. To reveal the effectiveness of the proposed scheme, we compare its necessary beam training overhead with that of existing schemes. Finally, the simulation results demonstrate that the proposed scheme can achieve accurate beam training in near-field wideband UCA systems with a low beam training overhead.

关键词： extremely large-scale antenna array (ELAA) uniform circular array (UCA) near-field wideband beam training