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Advancements in heterojunction,cocatalyst,defect and morphology engineering of semiconductor oxide photocatalysts

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Journal of Materiomics 2024年第2期10卷 315-338页

作者： Guojing Wang Shasha Lv Yuanhua Shen Wei Li Linhan Lin Zhengcao Li State Key Laboratory of New Ceramics and Fine Processing Key Laboratory of Advanced Materials(MOE)School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Key Laboratory of Beam Technology and Material Modification Ministry of EducationCollege of Nuclear Science and TechnologyBeijing Normal UniversityBeijing100875China School of Physical Science and Technology Lanzhou UniversityLanzhou730000China Department of engineering Physics Tsinghua UniversityBeijing100084China State Key Laboratory of precision Measurement Technology and instruments Department of Precision InstrumentTsinghua UniversityBeijing100084China

Photocatalytic technology has emerged as a crucial avenue for harnessing solar energy,presenting itself as a viable solution to address the current energy crisis and environmental *** past 50 years have witnessed significant progress and breakthroughs in scientific research on photocatalytic *** paper provides a comprehensive review of the mechanism of photocatalytic technology and methods to improve the photocatalytic efficiency of semiconductor photocatalysts,such as TiO 2 and *** this paper,common modification methods are divided into four categories:heterojunction con-struction,cocatalysts,defects,and morphological *** origin and development of photo-catalysts in each category are briefly summarized;moreover,the latest progress in each type of modification is discussed.S-scheme heterojunctions retain the high reduction and oxidation capacity of photogenerated electrons and holes by sacrificing half of the photogenerated carriers,showing excellent performance in photocatalysis and great application *** challenges associated with current modification schemes are *** is growing interest in quantitative and atomic-level modu-lation as attractive approaches to tackling these *** the electronic spin state and internal field is important for minimizing photogenerated carrier recombination in *** review will inspire researchers and promote the application of photocatalytic technology.

关键词： Photocatalytic activity Modification Heterostructure Thermal annealing Ion irradiation

Novel Batch Polishing Method of Ceramic Cutting Inserts for Reducing Tool Wear

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Chinese Journal of Mechanical engineering 2024年第4期37卷 74-83页

作者： Rui Gao Chunjin Wang Yee Man Loh Xiaoliang Liang Chen Jiang Chi Fai Cheung State Key Laboratory of Ultra-precision Machining Technology Department of Industrial and Systems EngineeringThe Hong Kong Polytechnic UniversityHong Kong 999077China college of Mechanical engineering University of Shanghai for Science and TechnologyShanghai 200093China

Ceramic cutting inserts are a type of cutting tool commonly used in high-speed metal cutting ***,the wear of these inserts caused by friction between the workpiece and cutting inserts limits their overall *** order to improve the tool life and reduce wear,this study introduces an emerging method called magnetic field-assisted batch polishing(MABP)for simultaneously polishing multiple ceramic cutting *** polishing experiments were conducted under different conditions,and the wear characteristics were clarified by cutting S136H *** results showed that after 15 min of polishing,the surface roughness at the flank face,edge,and nose of the inserts was reduced to below 2.5 nm,6.25 nm,and 45.8 nm,***,the nose radii of the inserts did not change significantly,and there were no significant changes in the weight percentage of elements before and after ***,the tool life of the batch polished inserts was found to be up to 1.75 times longer than that of unpolished *** findings suggest that the MABP method is an effective way to mass polish ceramic cutting inserts,resulting in significantly reduced tool ***,this novel method offers new possibilities for polishing other tools.

关键词： Polishing Finishing Magnetic field-assisted Tool wear Ultra-precision machining

Multi-junction cascaded vertical-cavity surface-emitting laser with a high power conversion efficiency of 74%

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Light(Science & Applications) 2024年第3期13卷 555-565页

作者： Yao Xiao Jun Wang Heng Liu Pei Miao Yudan Gou Zhicheng Zhang Guoliang Deng Shouhuan Zhou college of electronics and Information engineering Sichuan UniversityChengdu 610064China Suzhou Everbright Photonics Co. LtdSuzhou 215163China

High electro-optical conversion efficiency is one of the most distinctive features of semiconductor lasers as compared to other types of *** further increase remains a significant *** enhancing the efficiency of edgeemitting lasers(EEL),which represent the highest efficiency among semiconductor lasers at present,is *** efficiency of vertical cavity surface emitting lasers(VCSELs)has always been relatively low compared to *** paper,combining modeling with experiments,demonstrates the potential of multi-junction cascaded VCSELs to achieve high efficiency beyond that of EELs,our simulations show,that a 20-junction VCSEL can achieve an efficiency of more than 88%at room *** fabricated VCSEL devices with different numbers of junctions and compared their energy efficiency.15-junction VCSELs achieved a maximum efficiency of 74%at room temperature under nanosecond driving current,the corresponding differential quantum efficiency exceeds 1100%,being the largest electro-optical conversion efficiency and differential quantum efficiency reported until now for VCSELs.

关键词： cascaded power cavity

AI-Driven Energy Optimization in UAV-Assisted Routing for Enhanced Wireless Sensor Networks Performance

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Computers, Materials & Continua 2024年第9期80卷 4085-4110页

作者： Syed Kamran Haider Abbas Ahmed Noman Mujeeb Khan Ali Nauman Sung Won Kim college of Internet of Things(IoT)engineering Hohai UniversityChangzhou213001China Department of Electrical and electronics engineering Beaconhouse International CollegeIslamabad44000Pakistan School of Computer Science and engineering Yeungnam UniversityGyeongsan38428Republic of Korea

In recent advancements within wireless sensor networks(WSN),the deployment of unmanned aerial vehicles(UAVs)has emerged as a groundbreaking strategy for enhancing routing efficiency and overall network *** research introduces a sophisticated framework,driven by computational intelligence,that merges clustering techniques with UAV mobility to refine routing strategies in *** proposed approach divides the sensor field into distinct sectors and implements a novel weighting system for the selection of cluster heads(CHs).This system is primarily aimed at reducing energy consumption through meticulously planned routing and path *** a greedy algorithm for inter-cluster dialogue,our framework orchestrates CHs into an efficient communication *** comparative analysis,the proposed model demonstrates a marked improvement over traditional methods such as the cluster chain mobile agent routing(CCMAR)and the energy-efficient cluster-based dynamic algorithms(ECCRA).Specifically,it showcases an impressive 15%increase in energy conservation and a 20%reduction in data transmission time,highlighting its advanced ***,this paper investigates the impact of various network parameters on the efficiency and robustness of the WSN,emphasizing the vital role of sophisticated computational strategies in optimizing network operations.

关键词： UAV trajectory clustering next-generation wireless sensor network(NGWSN) energy efficiency mobile sink

Controlling underestimation bias in reinforcement learning via minmax operation

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Chinese Journal of Aeronautics 2024年第7期37卷 406-417页

作者： Fanghui HUANG Yixin HE Yu ZHANG Xinyang DENG Wen JIANG School of electronics and Information Northwestern Polytechnical UniversityXi’an 710129China college of Information Science and engineering Jiaxing UniversityJiaxing 314001China

Obtaining the accurate value estimation and reducing the estimation bias are the key issues in reinforcement ***,current methods that address the overestimation problem tend to introduce underestimation,which face a challenge of precise decision-making in many *** address this issue,we conduct a theoretical analysis of the underestimation bias and propose the minmax operation,which allow for flexible control of the estimation ***,we select the maximum value of each action from multiple parallel state-action networks to create a new state-action value ***,a minimum value is selected to obtain more accurate value ***,based on the minmax operation,we propose two novel algorithms by combining Deep Q-Network(DQN)and Double DQN(DDQN),named minmax-DQN and ***,we conduct theoretical analyses of the estimation bias and variance caused by our proposed minmax operation,which show that this operation significantly improves both underestimation and overestimation biases and leads to the unbiased ***,the variance is also reduced,which is helpful to improve the network training ***,we conduct numerous comparative experiments in various environments,which empirically demonstrate the superiority of our method.

关键词： Reinforcement learning Minmax operation Estimation bias Underestimation bias Variance

Tribological behavior of shape-specific microplate-enriched synovial fluids on a linear two-axis tribometer

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Friction 2024年第3期12卷 539-553页

作者： Agnese FRAGASSI Antonietta GRECO Martina DI FRANCESCO Luca CESERACCIU Aiman ABU AMMAR Israel DVIR Thomas Lee MOORE Haytam KASEM Paolo DECUZZI Laboratory of Nanotechnology for precision Medicine Fondazione Istituto Italiano di TecnologiaGenova 16163Italy Department of Chemistry and Industrial Chemistry University of GenovaGenoa 16146Italy Materials Characterization Facility Istituto Italiano di TecnologiaGenova 16163Italy Department of Pharmaceutical engineering Azrieli College of Engineering JerusalemJerusalem 9103501Israel Department of Mechanical engineering Azrieli College of Engineering JerusalemJerusalem 9103501Israel

Nano-and micro-particles are being increasingly used to tune interfacial frictional properties in diverse applications,from friction modifiers in industrial lubrication to enhanced biological fluids in human osteoarthritic ***,we assessed the tribological properties of a simulated synovial fluid enriched with non-spherical,poly lactic-co-glycolic acid(PLGA)microparticles(μPL)that have been previously demonstrated for the pharmacological management of osteoarthritis(OA).Three different μPL configurations were fabricated presenting a 20μm×20μm square base and a thickness of 5μm(thin,5H μPL),10μm(10H μPL),and 20μm(cubical,20H μPL).After extensive morphological and physicochemical characterizations,the apparent Young’s modulus of the μPL was quantified under compressive loading returning an average value of~6 kPa,independently of the particle ***,using a linear two-axis tribometer,the static(μ_(s))and dynamic(μ_(d))friction coefficients of the μPL-enriched simulated synovial fluid were determined in terms of particle configuration and concentration,varying from 0(fluid only)to 6×10^(5) μPL/*** particle morphology had a modest influence on friction,possibly because the μPL were fully squeezed between two mating surfaces by a 5.8 N normal load realizing boundary-like lubrication ***,friction was observed to depend on the dimensionless parameterW,defined as the ratio between the total volume of the μPL enriching the simulated synovial fluid and the volume of the fluid *** coefficients of friction were documented to grow withWreaching a plateau of μ_(s)~0.4 and μ_(d)~0.15,already at Ω~2×10^(-3).Future investigations will have to systematically analyze the effect of sliding velocity,normal load,and rigidity of the mating surfaces to elucidate in full the tribological behavior of μPL in the context of osteoarthritis.

关键词： osteoarthritis microparticles tribology synovial fluid pin on plate

An Intelligent Big Data Security Framework Based on AEFS-KENN Algorithms for the Detection of Cyber-Attacks from Smart Grid Systems

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Big Data Mining and Analytics 2024年第2期7卷 399-418页

作者： Sankaramoorthy Muthubalaji Naresh Kumar Muniyaraj Sarvade Pedda Venkata Subba Rao Kavitha Thandapani Pasupuleti Rama Mohan Thangam Somasundaram Yousef Farhaoui Department of Electrical and electronics engineering CMR College of Engineering&TechnologyHyderabad 501401India Department of electronics and Communication engineering Vardhaman College of Engineering KacharamShamshabad 501218India Department of electronics and Communication engineering Sreenidhi Institute of Science and TechnologyHyderabad 501301India Department of electronics and Communication engineering Vel Tech Rangarajan Dr.Sagunthala R&D Institute of Science and TechnologyChennai 600062India Department of Electrical and electronics engineering Bharat Institute of Engineering and TechnologyHyderabad 501510India Department of Computer Science and engineering Amrita School of ComputingAmrita Vishwa VidhyapeethamBengaluru 560035India T-IDMS Department of Computer ScienceFaculty of Sciences and TechniquesMoulay Ismail UniversityErrachidia 52000Morocco

Big data has the ability to open up innovative and ground-breaking prospects for the electrical grid,which also supports to obtain a variety of technological,social,and financial *** is an unprecedented amount of heterogeneous big data as a consequence of the growth of power grid technologies,along with data processing and advanced *** main obstacles in turning the heterogeneous large dataset into useful results are computational burden and information *** original contribution of this paper is to develop a new big data framework for detecting various intrusions from the smart grid systems with the use of AI ***,an AdaBelief Exponential Feature Selection(AEFS)technique is used to efficiently handle the input huge datasets from the smart grid for boosting ***,a Kernel based Extreme Neural Network(KENN)technique is used to anticipate security vulnerabilities more *** Polar Bear Optimization(PBO)algorithm is used to efficiently determine the parameters for the estimate of radial basis ***,several types of smart grid network datasets are employed during analysis in order to examine the outcomes and efficiency of the proposed AdaBelief Exponential Feature Selection-Kernel based Extreme Neural Network(AEFS-KENN)big data security *** results reveal that the accuracy of proposed AEFS-KENN is increased up to 99.5%with precision and AUC of 99%for all smart grid big datasets used in this study.

关键词： smart grid Machine Learning(ML) big data analytics AdaBelief Exponential Feature Selection(AEFS) Polar Bear Optimization(PBO) Kernel Extreme Neural Network(KENN)

Dielectric anisotropy in liquid crystal mixtures with nematic and smectic phases

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Chinese Physics B 2024年第8期33卷 519-524页

作者：汤星舟叶家耀王子烨姜皓译尚小虎杨朝雁李炳祥 Nanjing University of Posts and Telecommunications College of Electronic and Optical Engineering&College of Flexible Electronics(Future Technology)Nanjing 210023China National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesNanjing UniversityNanjing 210023China

The modulation of dielectric anisotropy(△ε)is pivotal for elucidating molecular interactions and directing the alignment of liquid *** this study,we combine liquid crystals with opposing dielectric anisotropies to explore the impact of varying concentrations on their *** report the sign-reversal of△εin both the nematic and smectic A phases of these mixed liquid crystals,alongside a dual-frequency behaviour across a broad temperature *** research further quantifies the influence of mixture ratios under various temperatures and electric field *** exploration may pave the way for the discovery of new physical phenomena.

关键词： mixed liquid crystal dielectric anisotropy tunable nematic smectic

Surface treatment of GaN nanowires for enhanced photoelectrochemical water-splitting

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Chinese Chemical Letters 2024年第9期35卷 398-402页

作者： Wenhao Chen Jian Du Hanbin Zhang Hancheng Wang Kaicheng Xu Zhujun Gao Jiaming Tong Jin Wang Junjun Xue Ting Zhi Longlu Wang college of Integrated Circuit Science and engineering Nanjing University of Posts and TelecommunicationsNanjing 210023China college of Electronic and Optical engineering&college of Flexible electronics(Future Technology) Nanjing University of Posts and TelecommunicationsNanjing 210023China

High-efficiency hydrogen production through photoelectrochemical(PEC)water splitting has emerged as a promising solution to address current global energy challenges.Ⅲ-nitride semiconductor photoelectrodes with nanostructures have demonstrated great potential in the near future due to their high light absorption,tunable direct band gap,and strong physicochemical ***,several issues,including surface trapping centers,surface Fermi level pinning,and surface band bending,need to be *** this work,enhanced photovoltaic properties have been achieved using gallium nitride(GaN)nanowires(NWs)photoelectrodes by adopting an alkaline solution surface treatment method to reduce the surface *** was found that surface oxides on NWs can be removed by an alkaline solution treatment without changing the surface morphology through X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM)and other characterization *** findings provide new insights to the development of high-efficiency photoelectrodes for new energy source applications.

关键词： Water splitting Photoelectrochemical cells Gallium nitride Surface treatment Nano-architectures