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Erosion Characteristics of Oil-immersed On-load Tap Changer Contacts Under Varying Contact Speeds and Pressures

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Chinese Journal of Electrical Engineering 2024年第1期10卷 21-34页

作者： Zongying li Shuaibing li Yongqiang Kang Zheng li Hongwei li School of New Energy and Power Engineering Lanzhou Jiaotong UniversityLanzhou 730070China School of Electrical Engineering Southwest Jiaotong UniversityChengdu 611756China School of Automation and Electrical Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

With the growing demand for precise voltage adjustment and reactive regulation,the frequent operation of on-load tap changers(OLTCs)in oil-immersed systems has led to increased erosion of switch contacts by arcs during the switching *** erosion causes significant wear on the contacts,thereby reducing their ***,the present study aims to investigate the behavior and mechanism of arc erosion on contact surfaces in oil-immersed *** achieve this,a self-designed friction and wear test device for OLTC contacts was utilized to conduct experiments at various sliding speeds and contact ***,finite element analysis was employed to validate the experimental results regarding the influence of sliding speed on arc *** surface morphology of the contacts was observed using an optical *** findings revealed that as the sliding speed increased,the arc energy,arc initiation rate,and contact resistance initially exhibited an upward trend,then decreased,and eventually increased *** minimum values were observed at a sliding speed of 90 mm/***,the arc energy,arc initiation rate,and contact resistance decreased gradually as the contact pressure *** reaching a contact pressure of 1.5 N,the variation in the arc energy *** lower contact pressures,arc erosion dominated the wear on the contact ***,at higher contact pressures,the wear transitioned from predominantly arc erosion to a combination of mechanical wear and arc *** summary,experimental and analytical investigations provided insights into the effects of sliding speed and contact pressure on the behavior of arc erosion,contact resistance,and surface damage of OLTC contacts in oil-immersed systems.

关键词： Oil-immersed on-load tap changer arc energy contact resistance friction and wear arc erosion

Coupling interface constructions of hollow Co-Mo mixed multiple oxidation states heterostructure for high-performance aprotic li-O_(2) battery

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Nano Research 2024年第5期17卷 4100-4107页

作者： Xingzi Zheng Mengwei Yuan Jingshen Xu Zihan li Caiyun Nan Genban Sun Beijing Key Laboratory of Energy Conversion and Storage Materials College of ChemistryBeijing Normal UniversityBeijing 100875China Center for Advanced Materials Research Beijing Normal UniversityZhuhai 519087China

Constructing interfaces in heterostructures is effective for modulating the electronic properties of *** hollow CoMoO_(4)-Co_(3)O_(4) heterostructure(HCMCH)was prepared as a bifunctional electrocatalyst for li-O_(2) *** different components in CoMoO_(4)-Co_(3)O_(4) heterostructure presented the efficient coupling and enhanced the electrocatalytic activity for aprotic oxygen reduction reaction(ORR)and oxygen evolution reaction(OER),in which it improved the obviously reduced overpotential of 300 mV(compared with the pure Ketjen black(KB)electrode),enhanced reversibility of 80%capacity retention after 6 full cycles and the superior cyclability of more than 200 cycles with an optimized *** battery performance of the HCMCH was not only associated with the unique hollow structure and rich active sites but also with coupling interface constructions synergetic effects attaching to the improving conductivity and optimized the discharge *** results suggested that this HCMCH electrocatalyst was a promising candidate for the li-O_(2) battery and it gave a novel insight for high performance electrocatalyst designing.

关键词： li-oxygen battery heterostructure electrocatalyst coupling interface

Nanoscale Zero-Valent Iron(nZVI)for Heavy Metal Wastewater Treatment:A Perspective

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Engineering 2024年第5期36卷 16-20页

作者： Shaolin li Lei li Weixian Zhang State Key Laboratory for Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

Industries such as non-ferrous metal smelting discharge billions of gallons of highly toxic heavy metal wastewater(HMW)worldwide annually,posing a severe challenge to conventional wastewater treatment plants and harming the *** is traditionally treated via chemical precipitation using lime,caustic,or sulfide,but the effluents do not meet the increasingly stringent discharge *** issue has spurred an increase in research and the development of innovative treatment technologies,among which those using nanoparticles receive particular *** such initiatives,treatment using nanoscale zero-valent iron(nZVI)is one of the best *** nZVI is already well known for its site-remediation use,this perspective highlights its application in HMW treatment with metal *** demonstrate several advantages of nZVI in this wastewater application,including its multifunctionality in sequestrating a wide array of metal(loid)s(>30 species);its capability to capture and enrich metal(loid)s at low concentrations(with a removal capacity reaching 500 mg·g^(-1)nZVI);and its operational convenience due to its unique *** these advantages are attributable to nZVI’s diminutive nanoparticle size and/or its unique iron *** also present the first engineering practice of this application,which has treated millions of cubic meters of HMW and recovered tons of valuable metals(e.g.,Cu and Au).It is concluded that nZVI is a potent reagent for treating HMW and that nZVI technology provides an eco-solution to this toxic waste.

关键词： Nanoscale zero-valent iron Wastewater Heavy metal Resource recovery

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银杏大麦酒的酿造工艺及品质分析

中国酿造 2019年第1期38卷 193-199页

作者：李傲然胡倬瑜杨宁孙郡何静仁何毅武汉轻工大学食品科学与工程学院湖北省农产品加工与转化重点实验室大宗粮油精深加工省部共建教育部重点实验室湖北武汉430023

以银杏果和大麦为原料,研究银杏大麦酒的酿造工艺,通过比较不同品牌酵母产酒精能力的大小选择广西丹宝利酵母作为银杏大麦酒的发酵菌。研究了不同的酵母菌接种量、发酵温度、初始pH值、初始糖度对银杏大麦酒酒精含量的影响;在此基础上... 详细信息

以银杏果和大麦为原料,研究银杏大麦酒的酿造工艺,通过比较不同品牌酵母产酒精能力的大小选择广西丹宝利酵母作为银杏大麦酒的发酵菌。研究了不同的酵母菌接种量、发酵温度、初始pH值、初始糖度对银杏大麦酒酒精含量的影响;在此基础上进行了4因素3水平银杏大麦酒发酵工艺条件的响应面试验优化。结果表明,银杏大麦酒发酵的最佳工艺条件为:初始糖度22.80°Bx、接种量0.24%、初始pH值3.70、发酵温度27.0℃。在此优化条件下,银杏大麦酒的酒精度为11.46%vol,测定其在最佳酿造过程中总酸、总酚、总黄酮含量及抗氧化性能力。结果表明,银杏大麦酒中总酸、总酚以及总黄酮含量最高分别为121 mg/100 m L、0.34 mg/m L、1.6 mg/m L,且具有良好的抗氧化活性。

关键词：银杏大麦酒酿造工艺抗氧化性响应面试验

A Novel 6G Scalable Blockchain Clustering-Based Computer Vision Character Detection for Mobile Images

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Computers, Materials & Continua 2024年第3期78卷 3041-3070页

作者： Yuejie li Shijun li Department of Mathematics and Computer Engineering Ordos Institute of TechnologyOrdos017000China School of Mathematics and Physics North China Electric Power UniversityBeijing102206China School of Electrical Information Hunan University of EngineeringXiangtan411104China

6G is envisioned as the next generation of wireless communication technology,promising unprecedented data speeds,ultra-low Latency,and ubiquitous *** tandem with these advancements,blockchain technology is leveraged to enhance computer vision applications’security,trustworthiness,and *** the widespread use of mobile devices equipped with cameras,the ability to capture and recognize Chinese characters in natural scenes has become increasingly *** can facilitate privacy-preserving mechanisms in applications where privacy is paramount,such as facial recognition or personal healthcare *** can control their visual data and grant or revoke access as *** Chinese characters from images can provide convenience in various aspects of people’s ***,traditional Chinese character text recognition methods often need higher accuracy,leading to recognition failures or incorrect character *** contrast,computer vision technologies have significantly improved image recognition *** paper proposed a Secure end-to-end recognition system(SE2ERS)for Chinese characters in natural scenes based on convolutional neural networks(CNN)using 6G *** proposed SE2ERS model uses the Weighted Hyperbolic Curve Cryptograph(WHCC)of the secure data transmission in the 6G network with the blockchain *** data transmission within the computer vision system,with a 6G gradient directional histogram(GDH),is employed for character *** the deployment of WHCC and GDH in the constructed SE2ERS model,secure communication is achieved for the data transmission with the 6G *** proposed SE2ERS compares the performance of traditional Chinese text recognition methods and data transmission environment with 6G *** results demonstrate that SE2ERS achieves an average recognition accuracy of 88%for simple Chinese characters,compared to 81.2%with traditional ***

关键词： 6G technology blockchain end-to-end recognition Chinese characters natural scene computer vision algorithms convolutional neural network

A novel micro-rolling&incremental sheet forming hybrid process:Deformation behavior and microstructure evolution

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Chinese Journal of Aeronautics 2024年第5期37卷 603-622页

作者： Yanle li Feifei liU Hao YUAN Xiaoqiang li Jianfeng li Guoqun ZHAO Key Laboratory of High Efficiency and Clean Mechanical Manufacture Ministry of EducationShandong UniversityJi'nan 250061China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Key Laboratory for liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong UniversityJi'nan 250061China

Thin-walled metal parts with functional micro-featured surface have broad application prospects in the fields of resistance reduction,noise reduction,*** this study,a novel micro-rolling&incremental sheet forming hybrid process(μR-ISF)is proposed to fabricate thin-walled metal parts with microgroove *** analytical model which relates the rolling force and microgroove depth in the micro-rolling stage was first ***,the formation mechanism of microgroove morphology during both micro-rolling stage and macro-shape forming stage are *** the micro-grooved sheet being incrementally formed,a significant reduction(between 21%to nearly 60%)is occurred in the depth of both transverse and longitudinal grooves compared to the flat ***,the width of transverse grooves decreases slightly by about 10%on average,while the width of longitudinal microgrooves increases significantly by more than 30%on *** micro-rolling,85°{102}tensile twins appear on the micro-grooved sheet and the percentage of 65°{112}compressive twins *** incremental forming,the percentage of low-angle grain boundaries and the density of geometrically necessary dislocations in the formed part increase significantly,and the grain size distribution becomes more *** present work provides a new strategy for the fabrication of 3D metal thin-walled components with surface micro-features.

关键词： Incremental sheet forming Microgrooves rolling Surface micromachining Groove size Microstructural evolution

A hybrid nickel/iron-pyromellitic acid electrocatalyst for oxygen evolution reaction

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Nano Research 2024年第4期17卷 2481-2491页

作者： Guoqi li lin li Wenlong li Fusheng li Chunze Yuan Nian Zhang Hui Zhang Tsu-Chien Weng School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Center for Transformative Science ShanghaiTech UniversityShanghai 201210China State Key Lab of Fine Chemicals Institute of Artificial PhotosynthesisDUT-KTH Joint Education and Research Center on Molecular DevicesDalian University of Technology(DUT)Dalian 116024China State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China

The migration of protons during the oxygen evolution reaction(OER)is a key factor that affects the performance of OER *** enhance proton transportation,we designed a catalyst based on nickel/iron-pyromellitic acid(NiFe-PMA)prepared by the electrochemical deposition *** catalyst exhibited a low overpotential of 188 mV at a current density of 10 mA·cm^(-2),a Tafel slope of 28.2 mV·dec^(-1),and long-term stability for 30 days with a current of 50 mA·cm^(-2).We characterized the NiFe-PMA catalyst using various techniques,including Fourier transform infrared(FTIR)spectroscopy,Raman spectroscopy,X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),and inductively coupled plasma-optical emission spectrometry(ICP-OES).Our results showed that NiFe-PMA contains nickel,iron atoms,and both coordinated and uncoordinated carboxylate ***,XPS data confirmed that carboxylate ligands could adjust the outer electronic structure of metal ions,resulting in the high valence state of Ni in *** result of XAS indicated that the nickel atoms present in the catalyst might be easier to maintain a higher chemical *** investigations using kinetic isotope effects(KIEs)and proton inventory revealed that the uncoordinated carboxylic protons played a crucial role in receiving protons during the OER,which promoted the proton transfer of the rate-determining step of the *** novel electrocatalysts provide a new strategy for designing more active and cost-effective catalysts for the OER.

关键词： nickel/iron-pyromellitic acid oxygen evolution reaction kinetic isotope effects

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

Phosphorylated cellulose nanofibers establishing reliable ion-sieving barriers for durable lithium-sulfur batteries

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Journal of Energy Chemistry 2024年第5期92卷 619-628页

作者： Zihao li Pengsen Qian Hongyang li He Xiao Jun Chen Gaoran li School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina National Forestry and Grassland Administration Key Laboratory of Plant Fiber Functional Materials Fuzhou 350108FujianChina

The shuttle effect is among the most characteristic and formidable challenges in the pursuit of high-performance lithium-sulfur(li-S)***,phosphorylated cellulose nanofibers(pCNF)are intentionally engineered to establish an ion-sieving barrier against polysulfide shuttling and thereby improve battery *** phosphorylation,involving the grafting of phosphate groups onto the cellulose backbone,imparts an exceptional electronegativity that repels the polysulfide anions from penetrating through the ***,the electrolyte wettability and li^(+)transfer can be significantly promoted by the polar nature of pCNF and the facile li^(+)*** such,rational ion management is realized,contributing to enhanced reversibility in both sulfur and lithium *** a result,li-S cells equipped with the self-standing pCNF separator demonstrate outstanding long-term cyclability with a minimum fading rate of 0.013%per cycle over 1000 cycles at 1 C,and a decent areal capacity of 5.37 mA h cm^(-2) even under elevated sulfur loading of 5.0 mg cm^(-2) and limited electrolyte of 6.0 mL g^(-1).This work provides a facile and effective pathway toward the well-tamed shuttle effect and highly durable li-S batteries.

关键词： lithium-sulfur batteries Cellulose Phosphorylation Ion-sieving Shuttle effect