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High-power Pr^(3+):YLF continuous wave lasers at 691.7 nm,701.4 nm,705.0 nm,and 708.7 nm

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Chinese Optics Letters 2024年第8期22卷 82-86页

作者： Run Fang Rongbin Dai Huiying Xu Zhiping Cai department of electronic Engineering Xiamen UniversityXiamen 361005China School of Physics and electronic Science Guizhou Normal UniversityGuiyang 550001China Fujian Key Laboratory of Ultrafast Laser Technology and Applications Xiamen UniversityXiamen 361005China

Lasers from^(1)I_(6)to^(3)F_(4)transitions were first demonstrated in a Pr^(3+):YLF crystal by inserting a birefringent *** powers up to 2.44 W,2.10 W,2.01 W,and 2.42 W were obtained at 691.7 nm,701.4 nm,705.0 nm,and 708.7 nm,*** slope efficiencies were 19.8%,16.5%,15.8%,and 19.4%,*** M_(x)^(2)and M_(y)^(2)factors were measured to be 2.29and 2.03 at 691.7 nm,2.23 and 1.86 at 701.4 nm,2.31 and 2.08 at 705.0 nm,and 2.41 and 2.04 at 708.7 nm,with corresponding power fluctuations of less than 5.3%,5.6%,5.8%,and 2.9%.

关键词： Pr^(3+):YLF laser high power laser Pr^(3+):YLF crystal

Biomechanical energy harvesting technologies for wearable electronics:Theories and devices

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Friction 2024年第8期12卷 1655-1679页

作者： Xiaowen LI Xu ZENG Junwei LI Boyuan LI Yu CHEN Xiaosheng ZHANG University of electronic Science and Technology of China Chengdu 611731China

Wearable biomechanical energy harvesting devices have received a lot of attention recently,benefiting from the rapid advancement of theories and devices in the field of the micro electromechanical system(MEMS).They not only fulfil the requirements for powering wearable electronic devices but also provide an attractive prospect for powering self-powered flexible electronic devices when *** this article,we provide a review of the theories and devices of biomechanical energy harvesting technology for wearable *** different forms of biomechanical energy harvesting mechanisms,including the piezoelectric effect,electromagnetic effect,and electrostatic effect,are investigated in *** fundamental principle of converting other types of energy from the biomechanical environment into electrical energy,as well as the most commonly-used analytical theoretical models,are outlined for each ***,the features,properties,and applications of energy harvesting devices are *** addition,the coupled multi-effect hybrid energy harvesting devices are listed,showing the various possibilities of biomechanical energy harvesting devices for serving as sources,sensors,and ***,we present perspectives on the future trends of biomechanical energy harvesting devices for wearable electronics applications.

关键词： micro electromechanical system(MEMS) nanogenerators biomechanical energy harvesters wearable electronics

Small-signal Stability Criteria in Power electronics-dominated Power Systems:A Comparative Review

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Journal of Modern Power Systems and Clean Energy 2024年第4期12卷 1003-1018页

作者： Qifan Chen Siqi Bu Chi Yung Chung department of Electrical and electronic Engineer The Hong Kong Polytechnic UniversityHong KongChina department of Electrical and electronic Engineering Shenzhen Research InstituteCentre for Grid ModernisationInternational Centre of Urban Energy NexusCentre for Advances in Reliability and SafetyResearch Institute for Smart Energyand Policy Research Centre for Innovation and TechnologyThe Hong Kong Polytechnic UniversityHong KongChina

To tackle emerging power system small-signal stability problems such as wideband oscillations induced by the large-scale integration of renewable energy and power electronics,it is crucial to review and compare existing small-signal stability analysis *** this basis,guidance can be provided on determining suitable analysis methods to solve relevant small-signal stability problems in power electronics-dominated power systems(PEDPSs).Various mature methods have been developed to analyze the small-signal stability of PEDPSs,including eigenvalue-based methods,Routh stability criterion,Nyquist/Bode plot based methods,passivity-based methods,positive-net-damping method,lumped impedance-based methods,bifurcation-based methods,*** this paper,the application conditions,advantages,and limitations of these criteria in identifying oscillation frequencies and stability margins are reviewed and compared to reveal and explain connections and discrepancies among ***,efforts are devoted to mathematically proving the equivalence between these small-signal stability ***,the performance of these criteria is demonstrated and compared in a 4-machine 2-area power system with a wind farm and an IEEE 39-bus power system with 3 wind farms.

关键词： Impedance-based method oscillation analysis power electronic converter power electronics-dominated power system renewable power generation small-signal stability

Epileptic brain network mechanisms and neuroimaging techniques for the brain network

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Neural Regeneration Research 2024年第12期19卷 2637-2648页

作者： Yi Guo Zhonghua Lin Zhen Fan Xin Tian department of Neurology Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina Sichuan Provincial Center for Mental Health Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina department of Geriatrics Sichuan Provincial People’s HospitalUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina department of Neurology Chongqing Key Laboratory of NeurologyThe First Affiliated Hospital of Chongqing Medical UniversityChongqingChina

Epilepsy can be defined as a dysfunction of the brain network,and each type of epilepsy involves different brain-network changes that are implicated diffe rently in the control and propagation of interictal or ictal *** more detailed information on brain network alterations can help us to further understand the mechanisms of epilepsy and pave the way for brain network-based precise therapeutic approaches in clinical *** increasing number of advanced neuroimaging techniques and electrophysiological techniques such as diffusion tensor imaging-based fiber tra ctography,diffusion kurtosis imaging-based fiber tractography,fiber ball imagingbased tra ctography,electroencephalography,functional magnetic resonance imaging,magnetoencephalography,positron emission tomography,molecular imaging,and functional ultrasound imaging have been extensively used to delineate epileptic *** this review,we summarize the relevant neuroimaging and neuroelectrophysiological techniques for assessing structural and functional brain networks in patients with epilepsy,and extensively analyze the imaging mechanisms,advantages,limitations,and clinical application ranges of each technique.A greater focus on emerging advanced technologies,new data analysis software,a combination of multiple techniques,and the construction of personalized virtual epilepsy models can provide a theoretical basis to better understand the brain network mechanisms of epilepsy and make surgical decisions.

关键词： electrophysiological techniques epilepsy functional brain network functional magnetic resonance imaging functional near-infrared spectroscopy machine leaning molecular imaging neuroimaging techniques structural brain network virtual epileptic models

Yttrium‐and nitrogen‐doped NiCo phosphide nanosheets for high‐efficiency water electrolysis

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Carbon Energy 2024年第8期6卷 214-231页

作者： Guangliang Chen Huiyang Xiang Yingchun Guo Jun Huang Wei Chen Zhuoyi Chen Tongtong Li Kostya(Ken)Ostrikov department of Materials Engineering Huzhou UniversityHuzhouChina School of Materials Science and Engineering Zhejiang Sci‐Tech UniversityHangzhouChina School of Physics and electronic Information Gannan Normal UniversityGanzhouChina School of Chemistry and Physics Centre for Materials ScienceCentre for Clean Energy Technologies and PracticesCentre for Waste−Free WorldQueensland University of Technology(QUT)BrisbaneQueenslandAustralia

Engineering high‐performance and low‐cost bifunctional catalysts for H_(2)(hydrogen evolution reaction[HER])and O_(2)(oxygen evolution reaction[OER])evolution under industrial electrocatalytic conditions remains ***,for the first time,we use the stronger electronegativity of a rare‐Earth yttrium ion(Y^(3+))to induce in situ NiCo‐layered double‐hydroxide nanosheets from NiCo foam(NCF)treated by a dielectric barrier discharge plasma NCF(PNCF),and then obtain nitrogen‐doped YNiCo phosphide(N‐YNiCoP/PNCF)after the phosphating process using radiofrequency plasma in *** obtained NYNiCoP/PNCF has a large specific surface area,rich heterointerfaces,and an optimized electronic structure,inducing high electrocatalytic activity in HER(331mV vs.2000mA cm^(−2))and OER(464mV vs.2000mA cm^(−2))reactions in 1MKOH electrolyte.X‐ray absorption spectroscopy and density functional theory quantum chemistry calculations reveal that the coordination number of CoNi decreased with the incorporation of Y atoms,which induce much shorter bonds of Ni and Co ions and promote long‐term stability of N‐YNiCoP in HER and OER under the simulated industrial ***,the CoN‐YP_(5)heterointerface formed by plasma N‐doping is the active center for overall water *** work expands the applications of rare‐Earth elements in engineering bifunctional electrocatalysts and provides a new avenue for designing highperformance transition‐metal‐based catalysts in the renewable energy field.

关键词： overall water splitting plasma etching plasma N‐doping rare‐earth electrocatalyst yttrium incorporation

Communication Resources Allocation for Time Delay Reduction of Frequency Regulation Service in High Renewable Penetrated Power System

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 468-480页

作者： Hongjie He Ning Zhang Chongqing Kang Song Ci Fei Teng Goran Strbac State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China department of Electrical and electronic Engineering Imperial College LondonSW72BULondonU.K

The high renewable penetrated power system has severe frequency regulation *** resources can provide frequency regulation services but are limited by com-munication time *** paper proposes a communication resources allocation model to reduce communication time delay in frequency regulation *** device resources and wireless spectrum resources are allocated to distributed resources when they participate in frequency *** reveal impact of communication resources allocation on time delay reduction and frequency regulation ***,we study communication resources allocation solution in high renewable energy penetrated power *** provide a case study based on the HRP-38 *** show communication time delay decreases distributed resources'ability to provide frequency regulation *** the other hand,allocating more communication resources to distributed resources'communica-tion services improves their frequency regulation *** power systems with renewable energy penetration above 70%,required communications resources are about five times as many as 30%renewable energy penetrated power systems to keep frequency performance the *** Terms-Communication resources allocation,commun-ication time delay,distributed resource,frequency regulation,high renewable energy penetrated power system.

关键词： Communication resources allocation communication time delay distributed resource frequency regulation high renewable energy penetrated power system

Advancing from scalar to vectorial liquid crystal holography:a paradigm shift

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Light(Science & Applications) 2024年第9期13卷 1696-1697页

作者： Yan Li Shin-Tson Wu department of electronic Engineering Shanghai Jiao Tong UniversityShanghai 200240China College of Optics and Photonics University of Central FloridaOrlandoFL 32816USA

A versatile and tunable vectorial holography is demonstrated based on single-layer single-material liquid crystal *** novel approach advances the process from scalar to vectorial holography,opening new opportunities f... 详细信息

关键词： liquid crystal versatile

A Hybrid Integrated and Low-Cost Multi-Chip Broadband Doherty Power Amplifier Module for 5G Massive MIMO Application

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Engineering 2024年第7期38卷 223-232页

作者： Fei Huang Guansheng Lv Huibo Wu Wenhua Chen Zhenghe Feng department of electronic Engineering Tsinghua UniversityBeijing 100084China

In this paper,a hybrid integrated broadband Doherty power amplifier(DPA)based on a multi-chip module(MCM),whose active devices are fabricated using the gallium nitride(GaN)process and whose passive circuits are fabricated using the gallium arsenide(GaAs)integrated passive device(IPD)process,is proposed for 5G massive multiple-input multiple-output(MIMO)*** inverted DPA structure with a low-Q output network is proposed to achieve better bandwidth performance,and a single-driver architecture is adopted for a chip with high gain and small *** proposed DPA has a bandwidth of 4.4-5.0 GHz that can achieve a saturation of more than 45.0 *** gain compression from 37 dBm to saturation power is less than 4 dB,and the average power-added efficiency(PAE)is 36.3%with an 8.5 dB peak-to-average power ratio(PAPR)in 4.5-5.0 *** measured adjacent channel power ratio(ACPR)is better than50 dBc after digital predistortion(DPD),exhibiting satisfactory linearity.

关键词： 5G Doherty power amplifier Multi-input multi-output Multi-chip modules Hybrid integrated

Hole-Transporting Materials with Rational Combination of Pyridine and Dibenzo[a,c]phenazine as Electron Acceptor for Dopant-Free Perovskite Solar Cells

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Chinese Journal of Chemistry 2024年第10期42卷 1100-1106页

作者： Weidong Ling Fei Wu Wentao Yuan Linna Zhu Qianqian Li Zhen Li Hubei Key Lab on Organic and Polymeric Opto-electronic Materials Department of ChemistryWuhan UniversityWuhanHubei 430072China Chongqing Key Laboratory for Advanced Materials and technologies of Clean Energy Faculty of Materials&EnergySouthwest UniversityChongqing400715China TaiKang Center for Life and Medical Sciences Wuhan UniversityWuhanHubei 430072China

Perovskite solar cells(PSCs)have been proven to be a promising option for photovoltaic *** the aim to achieve efficient and stable PSCs,it is essential to explore dopant-free hole-transporting materials(HTMs)with high hole ***,HTMs bearing electron donor(D)-electron acceptor(A)-electron donor(D)structures have been constructed with strong intramolecular charge transfer(ICT)effect,based on rational combination of dibenzo[a,c]phenazine and pyridine as electronic acceptors and anchoring groups to perovskite ***,high hole mobility(7.31×10^(-5) cm^(2)·V^(-1)·s^(-1))and photoelectric conversion efficiency(20.45%)have been achieved by dopant-free DPyP-based *** afforded an efficient way to design HTMs with high hole mobility by adjustment of molecular configurations and electronic property of conjugated systems.

关键词： Perovskite solar cell Charge transfer Donor-acceptor systems Energy conversion Hole mobility