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Drastic change in dynamics as Typhoon Lekima experiences an eyewall replacement cycle

Frontiers of Earth Science 2022年第1期16卷 121-131页

作者： Fen Xu X.San LIANG School of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China. School of Marine Sciences Nanjing University of Information Science and TechnologyNanjing 210044China

Why does the 1909 typhoon,Lekima,become so destructive after making landfall in China?Using a newly developed mathematical apparatus,the multiscale window transform(MWT),and the MWT-based localized mutliscale energetics analysis and theory of canonical transfer,this study is intended to give a partial answer from a dynamical point of view.The ECMWF reanalysis fields are first reconstructed onto the background window,the TC-scale window,and the convection-scale window.A localized energetics analysis is then performed,which reveals to us distinctly different scenarios before and after August 8–9,2019,when an eyewall replacement cycle takes place.Before that,the energy supply in the upper layer is mainly via a strong upper layer-limited baroclinic instability;the available potential energy thus-gained is then converted into the TC-scale kinetic energy,with a portion to fuel Lekima’s upper part,another portion carried downward via pressure work flux to maintain the cyclone’s lower part.After the eyewall replacement cycle,a drastic change in dynamics occurs.First,the pressure work is greatly increased in magnitude.A positive baroclinic transfer almost spreads throughout the troposphere,and so does barotropic transfer;in other words,the whole air column is now both barotropically and baroclinically unstable.These newly occurred instabilities help compensate the increasing consumption of the TC-scale kinetic energy,and hence help counteract the dissipation of Lekima after making landfalls.

关键词： Typhoon Lekima multiscale window transform canonical transfer multiscale energetics barotropic/baroclinic instability

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Synergistic effects of dodecane-castor oil acid mixture on the flotation responses of low-rank coal:A combined simulation and experimental study

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International Journal of Mining Science and Technology 2023年第5期33卷 649-658页

作者： Fen Xu Shiwei Wang Rongjie Kong Chengyong Wang College of Environmental and Chemical Engineering Dalian UniversityDalian 116622China School of Mines and Mechanical Engineering Liupanshui Normal UniversityLiupanshui 553004China

The utilization of an appropriate collector or surfactant is crucial for the beneficiation of low-rank coal.However,in previous studies,the selection of surfactants was primarily based on flotation procedures,which hinders the understanding of the interaction mechanism between surfactant groups and oxygen-containing functional groups at the surface of low-rank coal.In this study,we investigate the flotation of low-rank coal in the presence of a composite collector by using a combined theoretical and experimental approach.The maximum flotation mass recovery achieved was 82.89%using a 3:1 mixture of dodecane and castor oil acid.Fourier-transform infrared and X-ray photoelectron spectroscopic analyses showed that castor oil acid was effectively adsorbed onto the surface of low-rank coal,enhancing the hydrophobicity of the coal.In addition,the diffusion coefficient of water molecules in the water-composite collector-coal system was greater than that in the dodecane system.Moreover,due to the presence of castor oil acid in the flotation process,the adsorption distance of dodecane and low-rank coal became shorter.Molecular dynamics simulations revealed that the diffusion and interaction of surfactant molecules at the interface of low-rank coal particles and water was enhanced because the adsorption of the dodecane-castor oil acid mixture is primarily controlled by hydrogen bonds and electrostatic attraction.Based on these results,a better surfactant for flotation of low-rank coal is also proposed.

关键词： Low-rank coal Flotation Castor oil acid Surface hydrophobicity Molecular dynamics simulation

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MAFLD vs.NAFLD:shared features and potential changes in epidemiology,pathophysiology,diagnosis,and pharmacotherapy

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Chinese Medical Journal 2021年第1期134卷 8-19页

作者： Ying-Xin Xian Jian-Ping Weng Fen Xu Department of Endocrinology and Metabolism The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhouGuangdong 510630China Guangdong Provincial Key Laboratory of Diabetology GuangzhouGuangdong 510630China Department of Endocrinology of the First Affiliated Hospital Division of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefeiAnhui 230001China

Nonalcoholic fatty liver disease(NAFLD)is the most common chronic liver disease worldwide,placing an increasing burden on human health.NAFLD is a complex multifactorial disease involving genetic,metabolic,and environmental factors.It is closely associated with metabolic syndrome,obesity,and type 2 diabetes,of which insulin resistance is the main pathophysiological mechanism.Over the past few decades,investigation of the pathogenesis,diagnosis,and treatments has revealed different aspects of NAFLD,challenging the accuracy of definition and therapeutic strategy for the clinical practice.Recently,experts reach a consensus that NAFLD does not reflect the current knowledge,and metabolic(dysfunction)associated fatty liver disease(MAFLD)is suggested as a more appropriate term.The new definition puts increased emphasis on the important role of metabolic dysfunction in it.Herein,the shared features and potential changes in epidemiology,pathophysiology,diagnosis,and pharmacotherapy of the newly defined MAFLD,as compared with the formerly defined NAFLD,are reviewed for updating our understanding.

关键词： Nonalcoholic fatty liver disease Metabolic(dysfunction)associated fatty liver disease Epidemiology Pathophysiology Diagnosis Pharmacotherapy

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The progress of epigenetics in the development and progression of non-alcoholic fatty liver disease

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Liver Research 2020年第3期4卷 118-123页

作者： Fen Xu Wanrong Guo Department of Endocrinology and Metabolism The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhouChina Guangdong Provincial Key Laboratory of Diabetology GuangzhouChina

Non-alcoholic fatty liver disease(NAFLD)has become a global epidemic nowadays.Although the pathogenesis of NAFLD remains to be uncovered,it is highly correlated with the changing of environment as other metabolic diseases.Epigenetics is the study on the differences of gene expression not caused by the changes in DNA sequencing.The epigenetics is considered to link the environment factors and the onset and development of NAFLD.As an increasing number of researches on epigenetics have emerged in recent years,our understanding of how epigenetic factors take part in the pathogenesis of NAFLD has been improved.This article reviews the recent studies on important epigenetic factors contributing to the progression of NAFLD including the DNA methylation,modification of histones and non-coding RNAs.It may give us a hint to discover novel diagnosis methods and drug targets for NAFLD.

关键词： Non-alcoholic fatty liver disease(NAFLD) Metabolic associated fatty liver disease(MAFLD) Epigenetics DNA methylation Histone modifications Non-coding RNAs

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Three-dimensional Fusion of Spaceborne and Ground Radar Reflectivity Data Using a Neural Network–Based Approach

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Advances in Atmospheric Sciences 2018年第3期35卷 346-359页

作者： Leilei KOU Zhuihui WANG Fen Xu Key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science and Technology Nanjing 210044 China Meteorological Bureau of Jiangsu Province Nanjing 210008 China

The spaceborne precipitation radar onboard the Tropical Rainfall Measuring Mission satellite （TRMM PR） can provide good measurement of the vertical structure of reflectivity, while ground radar （GR） has a relatively high horizontal resolution and greater sensitivity. Fusion of TRMM PR and GR reflectivity data may maximize the advantages from both instruments. In this paper, TRMM PR and GR reflectivity data are fused using a neural network （NN）-based approach. The main steps included are： quality control of TRMM PR and GR reflectivity data; spatiotemporal matchup; GR calibration bias correction; conversion of TRMM PR data from Ku to S band; fusion of TRMM PR and GR reflectivity data with an NN method： interpolation of reflectivity data that are below PR＇s sensitivity; blind areas compensation with a distance weighting-based merging approach; combination of three types of data： data with the NN method, data below PR＇s sensitivity and data within compensated blind areas. During the NN fusion step, the TRMM PR data are taken as targets of the training NNs, and gridded GR data after horizontal downsampling at different heights are used as the input. The trained NNs are then used to obtain 3D high-resolution reflectivity from the original GR gridded data. After 3D fusion of the TRMM PR and GR reflectivity data, a more complete and finer-scale 3D radar reflectivity dataset incorporating characteristics from both the TRMM PR and GR observations can be obtained. The fused reflectivity data are evaluated based on a convective precipitation event through comparison with the high resolution TRMM PR and GR data with an interpolation algorithm.

关键词： TRMM PR ground radar 3D fusion neural network

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Nitrogen-doped hierarchical porous carbon materials derived from diethylenetriaminepentaacetic acid (DTPA) for supercapacitors

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Journal of Materials Science & Technology 2018年第12期34卷 2384-2391页

作者： Tinghuan Wu Lixian Sun Fen Xu Dan Cai School of Materials Science and Engineering Guilin University of Electronic TechnologyGuilin541004China Guangxi Key Laboratory oflnforrnation Materials Guilin 541004China Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials Guilin 541004China

Nitrogen-doped porous carbon materials（NPCs） have been successfully fabricated by a simple one-step pyrolysis of diethylenetriaminepentaacetic acid（DTPA） in the presence of KOH. The as-synthesized NPCs displayed a high specific surface area(3214 m;g;) and a well-defined porous structure when the annealing temperature reached 800 ℃, which showed superior electrochemical performance as supercapacitor electrode materials. Electrochemical tests showed that the NPCs achieved an impressive specific capacitance of 323 F g;at a current density of 0.5 A g;in 6 M KOH aqueous solution and an outstanding cycle stability, negligible specific capacitance decay after 5000 cycles at 10 A g;. This strategy offered a new insight into the preparation of novel carbon materials for the advanced energy storage devices, such as supercapacitors, fuel cells and lithium ion batteries.

关键词： Supercapacitors DTPA Nitrogen-doped porous carbon materials

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Fault Estimation for a Class of Markov Jump Piecewise-Affine Systems: Current Feedback Based Iterative Learning Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 418-429页

作者： Yanzheng Zhu Nuo xu fen Wu Xinkai Chen Donghua Zhou IEEE College of Electrical Engineering and Automation Shandong University of Science and TechnologyQingdao 266590China College of Mechanical Engineering and Automation Huaqiao UniversityXiamen 361021China Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleigh NC 27695 USA Department of Electronic and Information Systems Shibaura Institute of TechnologySaitama 337-8570Japan

In this paper, the issues of stochastic stability analysis and fault estimation are investigated for a class of continuoustime Markov jump piecewise-affine(PWA) systems against actuator and sensor faults. Firstly, a novel mode-dependent PWA iterative learning observer with current feedback is designed to estimate the system states and faults, simultaneously, which contains both the previous iteration information and the current feedback mechanism. The auxiliary feedback channel optimizes the response speed of the observer, therefore the estimation error would converge to zero rapidly. Then, sufficient conditions for stochastic stability with guaranteed performance are demonstrated for the estimation error system, and the equivalence relations between the system information and the estimated information can be established via iterative accumulating representation.Finally, two illustrative examples containing a class of tunnel diode circuit systems are presented to fully demonstrate the effectiveness and superiority of the proposed iterative learning observer with current feedback.

关键词： Current feedback fault estimation iterative learning observer Markov jump piecewise-affine system

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Identification of the flavor profiles of Chinese pancakes from various areas using smart instruments combined with E-noses and E-tongues

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International Journal of Agricultural and Biological Engineering 2023年第1期16卷 283-290页

作者： Wei Liu Yue Fan Qiannan Liu Fen Xu Liang Zhang Honghai Hu Institute of Food Science and Technology Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Products ProcessingMinistry of Agriculture and Rural AffairsBeijing 100193China

In order to reveal the flavor characteristics of Chinese pancakes,the aroma and taste compounds of seven traditional Chinese pancakes were identified.The results showed that electronic nose(E-nose)analysis with PCA could successfully distinguish the aroma profiles of seven Chinese pancakes;the principal components PC1 and PC2 represented 75.74%and 23.2%of the total variance(98.94%)respectively.Meanwhile,the discrimination index of taste profiles of seven Chinese pancakes based on electronic tongue(E-tongue)analysis with LDA was 99.32%;the discriminant factors DF1 and DF2 represented 94.99%and 4.33%of the total variance respectively.Furthermore,GC-MS results demonstrated that thirty-threeﬂavor compounds were identiﬁed in seven Chinese pancakes,including aldehydes,alcohols,alkanes,acids,and aromatics.Among the flavor components,aldehydes with ROAVs higher than 1 contributed most significantly to the overall aroma,such as(E,E)-2,4-nonadienal present the largest contribution in Qingzhou pancake,Jinan and Yishui pancake;hexanal present the largest contribution in Shenxian and Gaomi pancake;nonanal and benzeneacetaldehyde present the largest contribution in Linqu and Tai’an pancake,respectively.The umami and sweet taste amino acids were the most abundant in all the Chinese pancake samples,and Qingzhou pancake had relatively high amino acid content.The content of glucose was higher than maltose in Gaomi,Shenxian,and Tai’an pancakes,whereas the content of maltose was higher than glucose in Linqu,Qingzhou,Jinan,and Yishui pancakes.These results indicated that the aroma and taste proﬁles of Chinese pancakes differed significantly in terms of their flavor compound composition.The presented results could be beneficial for providing a comprehensive method for flavor profile identification of traditional whole-grain-based staples such as Chinese pancakes.

关键词： Chinese pancake flavor profile E-nose E-tongue smart instrument identification

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Interleukin 17A deficiency alleviates neuroinflammation and cognitive impairment in an experimental model of diabetic encephalopathy

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Neural Regeneration Research 2022年第12期17卷 2771-2777页

作者： Xiao-Xia Fang fen-Fen Xu Zhan Liu Bei-Bei Cao Yi-Hua Qiu Yu-Ping Peng Department of Physiology School of Medicineand Co-innovation Center of NeuroregenerationNantong UniversityNantongJiangsu ProvinceChina

Interleukin 17A(IL-17A)was previously shown to be a key pro-inflammatory factor in diabetes mellitus and associated complications.However,the role of IL-17A in diabetic encephalopathy remains poorly understood.In this study,we established a mouse model of diabetic encephalopathy that was deficient in IL-17A by crossing Il17a-/-mice with spontaneously diabetic Ins2^(Akita)(Akita)mice.Blood glucose levels and body weights were monitored from 2-32 weeks of age.When mice were 32 weeks of age,behavioral tests were performed,including a novel object recognition test for assessing short-term memory and learning and a Morris water maze test for evaluating hippocampus-dependent spatial learning and memory.IL-17A levels in the serum,cerebrospinal fluid,and hippocampus were detected with enzyme-linked immunosorbent assays and real-time quantitative polymerase chain reaction.Moreover,proteins related to cognitive dysfunction(amyloid precursor protein,β-amyloid cleavage enzyme 1,p-tau,and tau),apoptosis(caspase-3 and-9),inflammation(inducible nitric oxide synthase and cyclooxygenase 2),and occludin were detected by western blot assays.Pro-inflammatory cytokines including tumor necrosis factor-α,interleukin-1β,and interferon-γin serum and hippocampal tissues were measured by enzyme-linked immunosorbent assays.Microglial activation and hippocampal neuronal apoptosis were detected by immunofluorescent staining.Compared with that in wild-type mice,mice with diabetic encephalopathy had higher IL-17A levels in the serum,cerebrospinal fluid,and hippocampus;downregulation of occludin expression;lower cognitive ability;greater loss of hippocampal neurons;increased microglial activation;and higher expression of inflammatory factors in the serum and hippocampus.IL-17A knockout attenuated the abovementioned changes in mice with diabetic encephalopathy.These findings suggest that IL-17A participates in the pathological process of diabetic encephalopathy.Furthermore,IL-17A deficiency reduces diabetic encephalopathy-mediated neuroinflammati

关键词： Akita mice apoptosis cognitive impairment diabetic encephalopathy hippocampus interleukin 17A mice microglia neuroinflammation neuron targeted treatment

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Stabilized multifunctional phase change materials based on carbonized Cu-coated melamine foam/reduced graphene oxide framework for multiple energy conversion and storage

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Carbon Energy 2022年第6期4卷 1214-1227页

作者： Zhicong Hu Yongjin Zou Cuili Xiang Lixian Sun Fen Xu Menghe Jiang Sensen Yu Guangxi Key Laboratory of Information Materials Guilin University of Electronic TechnologyGuilinGuangxiPR China Guangxi Collaborative Innovation Center of Structure and Property for New Energy Materials GuilinGuangxiPR China

The leakage of organic phase change materials(OPCMs)at temperatures above their melting point severely limits their large-scale application.The introduction of porous supports has been identified as an efficient leakageproofing method.In this study,a novel carbonized Cu-coated melamine foam(MF)/reduced graphene oxide(rGO)framework(MF/rGO/Cu-C)is constructed as a support for fabricating stabilized multifunctional OPCMs.MF serves as the supporting material,while rGO and Cu act as functional reinforcements.As a thermal energy storage material,polyethylene glycol(PEG)is encapsulated into MF/rGO/Cu-C through a vacuum-assisted impregnation method to obtain PEG@MF/rGO/Cu-C composite with excellent comprehensive performance.PEG@MF/rGO/Cu-C exhibits high phase change enthalpies of 148.3 J g^(-1)(melting)and 143.9 J g^(-1)(crystallization),corresponding to a high energy storage capability of 92.7%.Simultaneously,MF/rGO/Cu-C endues the composite with an enhanced thermal conductivity of 0.4621Wm^(-1) K^(-1),which increases by 463%compared to that of PEG@MF.Furthermore,PEG@MF/rGO/Cu-C displays great light-to-thermal and electric-to-thermal conversion capabilities,thermal cycle stability,light-tothermal cycle stability,and shape stability,showing promising application prospects in different aspects.

关键词： Cu-coated network melamine foam PEG reduced graphene oxide stabilized multifunctional phase change materials

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