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Flashover Characteristics of Dry Band-water band on Hydrophobic Surfaces

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 392-400页

作者： Xiaohan Wu Fanghui Yin Bin Cao Daiming Yang Shichao Shao liming wang Tsinghua-Berkeley Shenzhen Institute(TBSI) Shenzhen 518055China Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China Shenzhen Polytechnic School Shenzhen 518055China

Due to their outstanding anti-flashover characteristics,composite insulators have been extensively applied in power systems.A lot of research has investigated flashover characteristics of hydrophobic specimens with artificial water droplets.However,the phenomenon is not consistent with that of the contaminated composite insulators.On the test specimens covered with water droplets,there is no obvious leakage current before the flashover and no obvious relationship between flashover voltage and the conductivity of water droplets.On the contaminated composite insulator surface,there are short continuous arcs on the insulators before critical flashover,making insulators look like a luminous lantern.Considering that under these two conditions,the proportion of water along the insulation distance is different,the flashover characteristic of“dry band-water band”on a hydrophobicity surface is analyzed in the present study.The influence of the water band parameter(including length,width,and conductivity)as well as the length of dry band is studied.On this basis,the arc generation and development process of the surface covered with“dry band-water band”is analyzed.The research results improve the understanding of the flashover process on contaminated composite insulators.

关键词： Flashover characteristics hydrophobicity partial arc water band

Preparation and performance improvement of a dual-component microcapsule self-healing system for silicone rubber insulating material

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High Voltage 2024年第2期9卷 453-465页

作者： Mingzhe Li Bin Cao Fanghui Yin Hongwei Mei liming wang Engineering Laboratory of Power Equipment Reliability in Complicated Coastal Environments Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhenChina

A key factor limiting the development of silicone rubber insulating materials is their short service life in harsh operating environments.The establishment of a self-healing system is desired to improve the long-term operational performance of silicone rubber and effectively extend its service life.In this study,poly(urea-formaldehyde)microcapsules containing polydimethylsiloxane healing agents are prepared and a dual-component microcapsule self-healing system for silicone rubber material is established and opti-mised.In addition,the key factors affecting the self-healing performance(such as microcapsule size,rupture rate,and microcapsule doping amount)are investigated.It is found that when SYLGARDTM 184 is used as the healing agent and matrix,with a 4:6(A:B)doping ratio of dual-component microcapsules and 20 phr doping amount,the self-healing efficiency is approximately 51%.Furthermore,increasing the microcapsule rupture rate and the interface strength between the healing agent and the matrix can effectively improve the self-healing performance.The relationships between key factors and self-healing performance are theoretically revealed.Based on the relationships,the microcapsule self-healing system can be appropriately designed.The results of this paper can provide a reference for the development of long-life silicone rubber insulating materials.

关键词： service rubber performance

CsRAXs negatively regulate leaf size and fruiting ability through auxin glycosylation in cucumber

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Journal of Integrative Plant Biology 2024年第5期66卷 1024-1037页

作者： Jiacai Chen Liu Liu Guangxin Chen Shaoyun wang Ye Liu Zeqin Zhang Hongfei Li liming wang Zhaoyang Zhou Jianyu Zhao Xiaolan Zhang Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops Department of Vegetable SciencesBeijing key Laboratoy of Growtn and Developmental Regul China Agricultural UniversityBeijing 100193China

Leaves are the main photosynthesis organ that directly determines crop yield and biomass.Dissecting the regulatory mechanism of leaf development is crucial for food security and ecosystem turn-over.Here,we identified the novel function of R2R3-MYB transcription factors CsRAXs in regulating cucumber leaf size and fruiting ability.Csrax5 single mutant exhibited enlarged leaf size and stem diameter,and Csrax1/2/5 triple mutant displayed further enlargement phenotype.Overexpression of CsRAX1 or CsRAX5 gave rise to smaller leaf and thinner stem.The fruiting ability of Csrax1/2/5 plants was significantly enhanced,while that of CsRAX5 overexpression lines was greatly weakened.Similarly,cell number and free auxin level were elevated in mutant plants while decreased in overexpression lines.Biochemical data indicated that CsRAX1/5 directly promoted the expression of auxin glucosyltransferase gene CsUGT74E2.Therefore,our data suggested that CsRAXs function as repressors for leaf size development by promoting auxin glycosylation to decrease free auxin level and cell division in cucumber.Our findings provide new gene targets for cucumber breeding with increased leaf size and crop yield.

关键词： auxin glycosylation CsRAXs CsUGT74E2 fruiting ability leaf size

Vaccinia virus viability under different environmental conditions and different disinfectants treatment

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Biosafety and Health 2024年第1期6卷 21-27页

作者： Shan Mei Liang Wei Yu Xie Fei Zhao Yu Huang Zhangling Fan Yamei Hu liming wang Lingwa wang Ying wang Fengwen Xu Fei Guo NHC Key Laboratory of Systems Biology of Pathogens National Institute of Pathogen Biology and Center for AIDS ResearchChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100730China Department of Otolaryngology Head and Neck Surgery Beijing Tongren HospitalCapital Medical UniversityBejing 100730China Clinical Laboratory Emergency General HospitalBeijing 100028China

Monkeypox(mpox)outbreak in 2022 has caused more than 91,000 cases,has spread to 115 countries,regions,and territories,and has thus attracted much attention.The stability of poxvirus particles in the environment is recognized as an important factor in determining their transmission.However,few studies have investigated the persistence of poxviruses on material surfaces under various environmental conditions,and their sensitivity to biocides.Here,we systematically measured the stability of vaccinia virus(VACV)under different environmental conditions and sensitivity to inactivation methods via plaque assay,quantitative real‐time polymerase chain reaction(qPCR),and Gaussia luciferase(G‐luciferase)reporter system.The results show that VACV is stable on the surface of stainless steel,glass,clothing,plastic,towel,A4 paper,and tissue and persists much longer at 4℃ and?20℃,but is effectively inactivated by ultraviolet(UV)irradiation,heat treatment,and chemical reagents.Our study raises the awareness of long persistence of poxviruses in the environment and provides a simple solution to inactivate poxviruses using common disinfectants,which is expected to help the control and prevention of mpox virus and future poxvirus outbreaks.

关键词： Poxvirus Mpox virus Vaccinia virus Persistence Disinfectant

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多功能热电织物用于可穿戴无线传感系统

Engineering 2024年第4期35卷 158-167页

作者： Xinyang He Jiaxin Cai Mingyuan Liu Xuepeng Ni Wendi Liu Hanyu Guo Jianyong Yu liming wang Xiaohong Qin Key Laboratory of Textile Science&Technology Ministry of EducationCollege of TextilesDonghua UniversityShanghai 201620China State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and EngineeringDonghua UniversityShanghai 201620China Innovation Center for Textile Science and Technology Donghua UniversityShanghai 201620China

Flexible thermoelectric materials play an important role in smart wearables,such as wearable power generation,self-powered sensing,and personal thermal management.However,with the rapid development of Internet of Things(IoT)and artificial intelligence(AI),higher standards for comfort,multifunctionality,and sustainable operation of wearable electronics have been proposed,and it remains challenging to meet all the requirements of currently reported thermoelectric devices.Herein,we present a multifunctional,wearable,and wireless sensing system based on a thermoelectric knitted fabric with over 600 mm·s^(-1)air permeability and a stretchability of 120%.The device coupled with a wireless transmission system realizes self-powered monitoring of human respiration through an mobile phone application(APP).Furthermore,an integrated thermoelectric system was designed to combine photothermal conversion and passive radiative cooling,enabling the characteristics of being powered by solar-driven in-plane temperature differences and monitoring outdoor sunlight intensity through the APP.Additionally,we decoupled the complex signals of resistance and thermal voltage during deformation under solar irradiation based on the anisotropy of the knitted fabrics to enable the device to monitor and optimize the outdoor physical activity of the athlete via the APP.This novel thermoelectric fabricbased wearable and wireless sensing platform has promising applications in next-generation smart textiles.

关键词： Thermoelectric fabrics Wearable device Wireless Multifunctional sensing system Outdoor wearable signal monitoring

A low-power Bluetooth-based wireless sensor network and its global confliction-solving impact localization method

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Chinese Journal of Aeronautics 2024年第1期37卷 153-161页

作者： Yuanjia wang Lei QIU Qiyun XU liming SHI College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Electrical and Electronic Engineering University of EdinburghEdinburgh EH89YLUK

During the whole service lifetime of aircraft structures with composite materials,impacts are inevitable and can usually cause severe but barely visible damages.Since the occurrences of impact are random and unpredictable,it is a hotspot direction to develop an online impact monitoring system that can meet strict limitations of aerospace applications including small size,light weight,and low power consumption.Piezoelectric(PZT)sensor,being able to generate impact response signals with no external power and cover a large-scale structure with only a small amount of them,is a promising choice.Meanwhile,for real systems,networks with multiple nodes are normally required to monitor large-scale structures in a global way to identify any impact localization confliction,yet the existing studies are mostly evaluated with single nodes instead of networks.Therefore,in this paper,based on a new low-power node designed,a Bluetooth-based digital impact monitoring PZT sensor network is proposed for the first time with its global confliction-solving impact localization method.Evaluations of the system as a network are researched and analyzed on a complex real aircraft wing box for a global confliction-solving impact localization,showing a satisfying high accuracy.

关键词： Bluetooth-based low-power design Confliction-solving evaluation Complex composites Piezoelectric sensors Wireless impact monitoring network

Tribological properties of PTFE-based fabric composites at cryogenic temperature

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Friction 2024年第2期12卷 245-257页

作者： Mingkun XU Zidan wang Lihe GUO liming TAO Tianbao MA Tingmei wang Qihua wang Key Laboratory of Science and Technology on Wear and Protection of Materials Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Fabric composites are widely employed in self-lubricating bearing liners as solid lubrication materials.Although the tribological behaviors of fabric composites have been extensively studied,the cryogenic tribological properties and mechanisms have been scarcely reported and are largely unclear to instruct material design for aerospace and other high-tech applications.Herein,the tribological properties of polytetrafluoroethylene(PTFE)-based hybrid-fabric composites were investigated at cryogenic and ambient temperatures in the form of pin-on-disk friction under heavy loads.The results suggest that the friction coefficients of the hybrid-fabric composites obviously increase with a decrease in wear when the temperature drops from 25 to−150°C.Moreover,thermoplastic polyetherimide(PEI),as an adhesive for fabric composites,has better cryogenic lubrication performance than thermosetting phenol formaldehyde(PF)resin,which can be attributed to the flexible chemical structure of PEI.The excellent lubrication performance of hybrid-fabric composites is attributed to the transfer film formed by PTFE fibers on the surface of fabrics.

关键词： cryogenic temperatures fabric composites friction and wear transfer film

Chemical vapor deposition for perovskite solar cells and modules

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Journal of Semiconductors 2024年第4期45卷 1-4页

作者： Zhihao Tao Yuxuan Song Baochang wang Guoqing Tong liming Ding School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Metal halide perovskites are promising materials for solar cells because of high power conversion efficiency(PCE),tun-able bandgap,high defect tolerance,long carrier diffusion length,and low-cost fabrication[1-7].The PCE for perovskite solar cells(PSCs)reaches 26.14%for single-junction cells,29.1%for perovskite/perovskite tandem cells and 33.9%for perovskite/silicon tandem cells,being comparable to that for silicon and other thin-film solar cells[8-10].Perovskite solar cells have been made by solution methods including spin-coat-ing,blade coating and printing[11,12].

关键词： perovskite blade film

Intelligent fault diagnosis methods toward gas turbine: A review

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Chinese Journal of Aeronautics 2024年第4期37卷 93-120页

作者： Xiaofeng LIU Yingjie CHEN Liuqi XIONG Jianhua wang Chenshuang LUO liming ZHANG Kehuan wang School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Systems Engineering Research Institute China State Shipbuilding CorporationBeijing 100094China

Fault diagnosis plays a significant role in conducting condition-based maintenance and health management for gas turbines(GTs) to improve reliability and reduce costs. Various diagnosis methods developed by modeling engine systems or certain components implement faults detection and diagnosis based on the measurement of systemic parameters deviations. However, these conventional model-based methods are hindered by limitations of inability to handle the nonlinear nature, measurement uncertainty, fault coupling and other implementing problems. Recently, the development of artificial intelligence algorithms has provided an effective solution to the above problems, triggering broad researches for data-driven fault diagnosis methods with better accuracy,dynamic performance, and universality. This paper presents a systematic review of recently proposed intelligent fault diagnosis methods for GT engines, according to the classification of shallow learning methods, deep learning methods and hybrid intelligent methods. Moreover, the principle of typical algorithms, the evolution of enhanced methods, and the assessment of pros and cons are summarized to conclude the present status and look forward to the future in the field of GT fault diagnosis. Possible directions for development in method validation, information fusion, and interpretability of intelligent diagnosis methods are concluded in the end to provide insightful concepts for scholars in related fields.

关键词： Fault diagnosis Health management Gas turbine Artificial intelligence Intelligent diagnosis method