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

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 process.This erosion causes significant wear on the contacts,thereby reducing their lifespan.Therefore,the present study aims to investigate the behavior and mechanism of arc erosion on contact surfaces in oil-immersed OLTCs.To achieve this,a self-designed friction and wear test device for OLTC contacts was utilized to conduct experiments at various sliding speeds and contact pressures.Additionally,finite element analysis was employed to validate the experimental results regarding the influence of sliding speed on arc energy.The surface morphology of the contacts was observed using an optical microscope.The 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 again.The minimum values were observed at a sliding speed of 90 mm/s.Moreover,the arc energy,arc initiation rate,and contact resistance decreased gradually as the contact pressure increased.After reaching a contact pressure of 1.5 N,the variation in the arc energy stabilized.At lower contact pressures,arc erosion dominated the wear on the contact surface.However,at higher contact pressures,the wear transitioned from predominantly arc erosion to a combination of mechanical wear and arc erosion.In 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

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Fibroblast growth factor 21: An emerging pleiotropic regulator of lipid metabolism and the metabolic network

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Genes & Diseases 2024年第3期11卷 248-263页

作者： Shuo li Tiande Zou Jun Chen Jiaming li Jinming You Jiangxi Province Key Laboratory of Animal Nutrition Jiangxi Agricultural UniversityNanchangJiangxi 330045China

Fibroblast growth factor 21(FGF21)was originally identified as an important meta-bolic regulator which plays a crucial physiological role in regulating a variety of metabolic pa-rameters through the metabolic network.As a novel multifunctional endocrine growth factor,the role of FGF21 in the metabolic network warrants extensive exploration.This insight was obtained from the observation that the FGF21-dependent mechanism that regulates lipid metabolism,glycogen transformation,and biological effectiveness occurs through the coordi-nated participation of the liver,adipose tissue,central nervous system,and sympathetic nerves.This review focuses on the role of FGF21-uncoupling protein 1(UCP1)signaling in lipid metabolism and how FGF21 alleviates non-alcoholic fatty liver disease(NAFLD).Additionally,this review reveals the mechanism by which FGF21 governs glucolipid metabolism.Recent research on the role of FGF21 in the metabolic network has mostly focused on the crucial pathway of glucolipid metabolism.FGF21 has been shown to have multiple regulatory roles in the metabolic network.Since an adequate understanding of the concrete regulatory path-ways of FGF21 in the metabolic network has not been attained,this review sheds new light on the metabolic mechanisms of FGF21,explores how FGF21 engages different tissues and organs,and lays a theoretical foundation for future in-depth research on FGF21-targeted treatment of metabolic diseases.

关键词： Adipose FGF21 Insulin homeostasis lipid metabolism liver Metabolicnetwork

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Kinetic and mechanism of the reaction between Cl and several mono-methyl branched alkanes

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Journal of Environmental Sciences 2024年第1期135卷 474-482页

作者： Yan Chen Weigang Wang Junling li li Zhou Bo Shi Cici Fan Ke Wang Hao Zhang Hong li Maofa Ge State Key Laboratory for Structural Chemistry of Unstable and Stable Species Beijing National Laboratory for Molecular Sciences(BNLMS)CAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China National Engineering Research Center for Flue Gas Desulfurization Department of Environmental Science and EngineeringSichuan UniversityChengdu 610065China College of Chemistry and Materials Science Hebei Normal UniversityShijiazhuang 050024China

Branched alkanes are ubiquitous in the troposphere and play an important role in the chemical processes.In this work,the rate constants and products for the reaction of Cl atoms with 3-methylhexane and 2-methylheptane were measured at room temperature(298±0.2K)and atmospheric pressure using a conventional relative rate method.The rate constants of 3-methylhexane and 2-methylheptane in units of cm~3/(mol·sec)are(3.09±0.31)×10^(-10)and(3.67±0.40)×10^(-10),respectively.Furthermore,the corresponding atmospheric lifetime of the studied branched alkanes with Cl was 6.92-89.90 hours and 5.82-75.69 hours,respectively.The estimated atmospheric lifetimes indicated that the reaction with Cl atoms could be the most important atmospheric degradation pathway for 3-methylhexane and2-methylheptane.Primary gas-phase products of the reactions were identified and quantified,and particle-phase products were also obtained.The atmosphere oxidation mechanism of Cl atoms with 3-methylhexane and 2-methylheptane is proposed.The SOA yields of 3-methylhexane and 2-methylheptane from the reaction of Cl atoms were determined to be7.96%±0.89%and 13.35%±1.50%respectively.Overall,the results reveal that the primary loss process of branched alkanes is the reaction with Cl atoms,which impacts its degradation on a regional scale.

关键词： 3-Methylhexane 2-Methylheptane Chlorine atoms Kinetics Mechanism

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OSMR is a potential driver of inflammation in amyotrophic lateral sclerosis

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Neural Regeneration Research 2024年第11期19卷 2513-2521页

作者： Wenzhi Chen Shishi Jiang Shu li Cheng li Renshi Xu Department of Neurology Jiangxi Provincial People’s HospitalXiangya Hospital Jiangxi Hospital of Central South UniversityThe Clinical College of Nanchang Medical CollegeThe First Affiliated Hospital of Nanchang Medical CollegeNanchangJiangxi ProvinceChina

Amyotrophic lateral sclerosis is a neurodegenerative disease,and the molecular mechanism underlying its pathology remains poorly understood.However,inflammation is known to play an important role in the development of this condition.To identify driver genes that affect the inflammatory response in amyotrophic lateral sclerosis,as well as potential treatment targets,it is crucial to analyze brain tissue samples from patients with both sporadic amyotrophic lateral sclerosis and C9orf72-related amyotrophic lateral sclerosis.Therefore,in this study we used a network-driven gene analysis tool,NetBID2.0,which is based on SJARACNe,a scalable algorithm for the reconstruction of accurate cellular networks,to experimentally analyze sequencing data from patients with sporadic amyotrophic lateral sclerosis.The results showed that the OSMR gene is pathogenic in amyotrophic lateral sclerosis and participates in the progression of amyotrophic lateral sclerosis by mediating the neuroinflammatory response.Furthermore,there were differences in OSMR activity and expression between patients with sporadic amyotrophic lateral sclerosis and those with C9orf72-related amyotrophic lateral sclerosis.These findings suggest that OSMR may be a diagnostic and prognostic marker for amyotrophic lateral sclerosis.

关键词： amyotrophic lateral sclerosis driver neuroinflammation OSMR C9ORF72 neurodegenerative disease pathogenesis oxidative stress protein misfolding mitochondrial dysfunction

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How does trip frequency distort time value to impact congestion charging schemes?

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Transportation Safety and Environment 2024年第1期6卷 22-39页

作者： Maosheng li Hangcong li School of Traffic and Transportation Engineering Central South UniversityChangshaHunan 410075China

A notable feature of a city or region with close economic and social connections with its neighbours is its highly mixed local and external traffic,and in some cases the external traffic volume is almost as high as that of local traffic.Whilst local traffic volume may be largely made up of the same regular local commuters making frequent trips,external traffic from outside of the city(region)may not be the same people making regular trips to/from the city.However,from a large pool of people making infrequent trips to/from the city,the existence of external traffic is proven by data from the licence plate recognition system of road vehicles in Changde,China.The function of value of time correlated with the income/wage rate and trip frequency is exploited and verified statistically.The time value distorted by trip frequency is defined as perceived time value(PTV),which also influences the way travellers perceive any travel impedance such as congestion delay and toll charges.This paper analyses the price of anarchy(POA)when explicitly considering the travel frequency of the trip-makers and their PTV,and compares with previous analysis without considering travel frequency.We show that when travel frequency is considered,the optimal toll of congested road pricing schemes which converts road traffic flow from user equilibrium into system optimization is much lower than that without considering travel frequency.The cost of licence plate auction cannot be treated as a congestion toll,which is only a threshold of vehicle ownership.That travellers choose routes by PTV rather than TV(time value)is proven by an example of Heishipu Bridge in Changsha,Hunan Province,China.

关键词： road congestion charging travel frequency perceived time value road traffic impedance price of anarchy

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Nicotinamide adenine dinucleotide treatment confers resistance to neonatal ischemia and hypoxia:effects on neurobehavioral phenotypes

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Neural Regeneration Research 2024年第12期19卷 2760-2772页

作者： Xiaowen Xu Xinxin Wang li Zhang Yiming Jin lili li Meifang Jin lianyong li Hong Ni Division of Brain Science Institute of Pediatric ResearchChildren’s Hospital of Soochow UniversitySuzhouJiangsu ProvinceChina Department of Pediatric Orthopedics Shengjing Hospital of China Medical UniversityShenyangLiaoning ProvinceChina

Neonatal hypoxic-ischemic brain injury is the main cause of hypoxic-ischemic encephalopathy and cerebral palsy.Currently,there are few effective clinical treatments for neonatal hypoxic-ischemic brain injury.Here,we investigated the neuroprotective and molecular mechanisms of exogenous nicotinamide adenine dinucleotide,which can protect against hypoxic injury in adulthood,in a mouse model of neonatal hypoxic-ischemic brain injury.In this study,nicotinamide adenine dinucleotide(5 mg/kg)was intraperitoneally administered 30 minutes befo re surgery and every 24 hours thereafter.The results showed that nicotinamide adenine dinucleotide treatment improved body weight,brain structure,adenosine triphosphate levels,oxidative damage,neurobehavioral test outcomes,and seizure threshold in experimental mice.Tandem mass tag proteomics revealed that numerous proteins were altered after nicotinamide adenine dinucleotide treatment in hypoxic-ischemic brain injury mice.Parallel reaction monitoring and western blotting confirmed changes in the expression levels of proteins including serine(or cysteine)peptidase inhibitor,clade A,member 3N,fibronectin 1,5'-nucleotidase,cytosolic IA,microtubule associated protein 2,and complexin 2.Proteomics analyses showed that nicotinamide adenine dinucleotide ameliorated hypoxic-ischemic injury through inflammation-related signaling pathways(e.g.,nuclear factor-kappa B,mitogen-activated protein kinase,and phosphatidylinositol 3 kinase/protein kinase B).These findings suggest that nicotinamide adenine dinucleotide treatment can improve neurobehavioral phenotypes in hypoxic-ischemic brain injury mice through inflammation-related pathways.

关键词： brain injury cerebral palsy hypoxia hypoxic-ischemic brain injury inflammation neuroprotection nicotinamide adenine dinucleotide neonate nicotinamide adenine dinucleotide proteomics

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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 catalysts.To enhance proton transportation,we designed a catalyst based on nickel/iron-pyromellitic acid(NiFe-PMA)prepared by the electrochemical deposition method.This 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 groups.Additionally,XPS data confirmed that carboxylate ligands could adjust the outer electronic structure of metal ions,resulting in the high valence state of Ni in NiFe-PMA.The result of XAS indicated that the nickel atoms present in the catalyst might be easier to maintain a higher chemical state.Further 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 OER.Our 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

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

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

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Rainbow Pancyclicity in a Collection of Graphs Under the Dirac-type Condition

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 269-274页

作者： Lu-yi li Ping li Xue-liang li Center for Combinatorics and LPMC Nankai UniversityTianjin 300071China School of Mathematics and Statistics Shaanxi Normal UniversityXi’an 710062China

Let G={Gi:i∈[n]} be a collection of not necessarily distinct n-vertex graphs with the same vertex set V,where G can be seen as an edge-colored(multi)graph and each Gi is the set of edges with color i.A graph F on V is called rainbow if any two edges of F come from different Gis’.We say that G is rainbow pancyclic if there is a rainbow cycle Cℓof lengthℓin G for each integerℓ2[3,n].In 2020,Joos and Kim proved a rainbow version of Dirac’s theorem:Ifδ(Gi)≥2/n for each i∈[n],then there is a rainbow Hamiltonian cycle in G.In this paper,under the same condition,we show that G is rainbow pancyclic except that n is even and G consists of n copies of Kn/2,n/2.This result supports the famous meta-conjecture posed by Bondy.

关键词： rainbow Hamiltonian cycle rainbow pancyclic meta-conjecture

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Rab18 maintains homeostasis of subcutaneous adipose tissue to prevent obesity-induced metabolic disorders

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Science China(life Sciences) 2024年第6期67卷 1170-1182页

作者： Jiaming liu liangkui li Dijin Xu Yuqi li Tao Chen Yeyang liu Yuqian Bao Yan Wang Longyan Yang Peng li li Xu State Key Laboratory of Membrane Biology and Tsinghua-Peking Center for life Sciences Beijing Advanced Innovation Center for Structural BiologySchool of Life SciencesTsinghua UniversityBeijing 100084China Shanghai Qi Zhi Institute Shanghai 200232China Shanghai Key Laboratory of Metabolic Remodeling and Health Institute of Metabolism and Integrative BiologyFudan UniversityShanghai 200438China Tianjian Laboratory of Advanced Biomedical Sciences Zhengzhou UniversityZhengzhou 450001China Department of Physiology School of Basic Medical SciencesGannan Medical UniversityGanzhou 341000China Department of Endocrinology and Metabolism Shanghai Jiao Tong University School of Medicine Affiliated Sixth People’s HospitalShanghai 200025China Center for Endocrine Metabolism and Immune Diseases Beijing Luhe HospitalCapital Medical UniversityBeijing 101149China Beijing Key Laboratory of Diabetes Research and Care Beijing 101149China

Metabolically healthy obesity refers to obese individuals who do not develop metabolic disorders.These people store fat in subcutaneous adipose tissue(SAT)rather than in visceral adipose tissue(VAT).However,the molecules participating in this specific scenario remain elusive.Rab18,a lipid droplet(LD)-associated protein,mediates the contact between the endoplasmic reticulum(ER)and LDs to facilitate LD growth and maturation.In the present study,we show that the protein level of Rab18 is specifically upregulated in the SAT of obese people and mice.Rab18 adipocyte-specific knockout(Rab18 AKO)mice had a decreased volume ratio of SAT to VAT compared with wildtype mice.When subjected to high-fat diet(HFD),Rab18 AKO mice had increased ER stress and inflammation,reduced adiponectin,and decreased triacylglycerol(TAG)accumulation in SAT.In contrast,TAG accumulation in VAT,brown adipose tissue(BAT)or liver of Rab18AKO mice had a moderate increase without ER stress stimulation.Rab18 AKO mice developed insulin resistance and systematic inflammation.Rab18 AKO mice maintained body temperature in response to acute and chronic cold induction with a thermogenic SAT,similar to the counterpart mice.Furthermore,Rab18-deficient 3T3-L1 adipocytes were more prone to palmitate-induced ER stress,indicating the involvement of Rab18 in alleviating lipid toxicity.Rab18 AKO mice provide a good animal model to investigate metabolic disorders such as impaired SAT.In conclusion,our studies reveal that Rab18 is a key and specific regulator that maintains the proper functions of SAT by alleviating lipid-induced ER stress.

关键词： Rab18 subcutaneous adipose tissue(SAT) metabolically healthy obesity(MHO) lipotoxicity ER stress ectopic lipid storage LD-ER contact

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