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Exploration and mitigation of protrusion behavior in Ga-ion doped h-BN memristors

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纳米技术与精密工程(英文) 2023年第3期6卷 10-17页

作者： Mucun Li Enxiu Wu Linyan Xu Xiaodong Hu Xiaopu Miao State Key Laboratory of Precision Measurement Technology and Instruments School of Precision Instruments and Opto-electronics EngineeringTianjin UniversityNo.92 Weijin RoadTianjin 300072People’s Republic of China State Key Laboratory of Transducer Technology Institute of ElectronicsChinese Academy of SciencesBeijing 100190People’s Republic of China

Using hexagonal boron nitride(h-BN)to prepare resistive switching devices is a promising strategy.Various doping methods have aroused great interest in the semiconductor field in recent years,but many researchers have overlooked the various repetitive anomalies that occur during the testing process.In this study,the basic electrical properties and additive protrusion behavior of Ga-ion-doped h-BN memristors at micro–nanoscale during the voltage scanning process are investigated via atomic force microscopy(AFM)and energy dispersive spectroscopy.The additive protrusion behavior is subjected to exploratory research,and it is concluded that it is caused by anodic oxidation.An approach is proposed that involves filling the AFM chamber with nitrogen gas to improve the stability of memristor testing,and this method provides a solution for enhanced testing stability of memristors.

关键词： Hexagonal boron nitride Memristor AFM Anodic oxidation

Neural network-based fault diagnosis for spacecraft with single-gimbal control moment gyros

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Chinese Journal of Aeronautics 2022年第7期35卷 261-273页

作者： Yuandong LI Qinglei hu xiaodong SHAO School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100083China Beihang Hangzhou Innovation Institute Yuhang Hangzhou 310023China School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China

This paper proposes a neural network-based fault diagnosis scheme to address the problem of fault isolation and estimation for the Single-Gimbal Control Moment Gyroscopes(SGCMGs)of spacecraft in a periodic orbit.To this end,a disturbance observer based on neural network is developed for active anti-disturbance,so as to improve the accuracy of fault diagnosis.The periodic disturbance on orbit can be decoupled with fault by resorting to the fitting and memory ability of neural network.Subsequently,the fault diagnosis scheme is established based on the idea of information fusion.The data of spacecraft attitude and gimbals position are combined to implement fault isolation and estimation based on adaptive estimator and neural network.Then,an adaptive sliding mode controller incorporating the disturbance and fault estimation results is designed to achieve active fault-tolerant control.In addition,the paper gives the proof of the stability of the proposed schemes,and the simulation results show that the proposed scheme achieves better diagnosis and control results than compared algorithm.

关键词： Control moment gyro Fault diagnosis Fault-tolerant control Neural networks Spacecraft attitude control

Spatial and Temporal Variations in the Atmospheric Age Distribution of Primary and Secondary Inorganic Aerosols in China

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Engineering 2023年第9期28卷 117-129页

作者： xiaodong Xie Qi Ying Hongliang Zhang Jianlin hu Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologyNanjing University of Information Science&TechnologyNanjing 210044China Zachry Department of Civil Engineering Texas A&M UniversityCollege StationTX 77843USA Department of Environmental Science and Engineering Fudan UniversityShanghai 200438China

The aging timescale of particles is a key parameter in determining their impacts on air quality,human health,and climate.In this study,a one-year simulation of the age distributions of the primary and secondary inorganic fine particulate matter(PM_(2.5))components was conducted over China using an age-resolved Community Multiscale Air Quality(CMAQ)model.The results indicate that primary PM_(2.5)(PPM)and ammonium mainly originate from fresh local emissions,with approximately 60%-80%concentrated in 0-24 h age bins in most of China throughout the year.The average age is about15-25 h in most regions in summer,but increases to 40-50 h in southern region of China and the Sichuan Basin(SCB)in winter.Sulfate is more aged than PPM,indicating an enhanced contribution from regional transport.Aged sulfate with atmospheric age>48 h account for 30%-50%of total sulfate in most regions and seasons,and the concentrations in the>96 h age bin can reach up to 15μg·m-3 in SCB during winter.Dramatic seasonal variations occur in the Yangtze River Delta,Pearl River Delta,and SCB,with highest average age of 60-70 h in winter and lowest of 40-45 h in summer.The average age of nitrate is 20-30 h in summer and increases to 40-50 h in winter.The enhanced deposition rate of nitric acid vapor combined with the faster chemical reaction rate of nitrogen oxides leads to a lower atmospheric age in summer.Additionally,on pollution days,the contributions of old age bins(>24 h)increase notably for both PPM and secondary inorganic aerosols in most cities and seasons,suggesting that regional transport plays a vital role during haze events.The age information of PM_(2.5),provided by the age-resolved CMAQ model,can help policymakers design effective emergent emission control measures to eliminate severe haze episodes.

关键词： Atmospheric age PM_(2.5) CMAQ model Control strategy

A lateral super-resolution imaging method using structured illumination without phase shift

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Nanotechnology and Precision Engineering 2019年第3期2卷 130-137页

作者： Yuan Jia Junsheng Lu Xinyu Chang Xiaodong Hu School of Precision Instruments&Opto-Electronics Engineering Tianjin UniversityTianjin 300072China State Key Laboratory of Precision Measuring Technology and Instruments Tianjin UniversityTianjin 300072China

Structured illumination microscopy has been a useful method for achieving lateral super-resolution,but it typically requires at least three precise phase shifts per orientation.In this paper,we propose a super-resolution method that utilizes structured illumination without phase shift.The reconstruction process requires only a conventionally illuminated image and an image with structured illumination.This method achieves the same effect as the traditional phase shift method,and more than doubles the resolution by synthesizing a few reconstructions at different illumination frequencies.We verify the resolution improvement process using a combination of theoretical derivations and diagrams,and demonstrate its effectiveness with numerical simulations.

关键词： Super-resolution Structured illumination Reconstruction Non phase shift

Key bottlenecks and distinct contradictions in fast commercialization of perovskite solar cells

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Materials Futures 2023年第1期2卷 61-69页

作者： Wenguang Liu Hasan Raza Xiaodong Hu Sanwan Liu Zonghao Liu Wei Chen Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074People’s Republic of China Optics Valley Laboratory Hubei 430074People’s Republic of China

Despite significant improvements in photo-electricity conversion efficiency of perovskite solar cells(PSCs)over the past several years,this emerging photovoltaic technology is still years away from large-scale commercial application.In this review,important research progresses on PSCs’‘golden triangle’parameters of efficiency,stability,and cost in literatures were objectively analyzed.We focused on their key bottlenecks and distinct contradictions hindering their fast commercialization.We also proposed the most urgent directions requiring intensive research and development input in the coming years to speed up the commercialization process of PSCs.

关键词： perovskite solar cell key bottlenecks contradictions commercial application

Preface: Wind turbines: aeromechanics and farm optimization

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Acta Mechanica Sinica 2020年第2期36卷 257-259页

作者： hui hu xiaodong Wang Department of Aerospace Engineering Iowa State UniversityAmesIA50011-1096USA Department of Energy Power and Mechanical Engineering of North China Electric Power UniversityBeijing102206China

1 Preface With the oil and gas supply security and climate change emerging as high concerns,the need for renewable energy sources to alleviate dependence on hydrocarbons and reduce carbon dioxide(CO2)emissions is becoming increasingly urgent.Wind energy is one of the cleanest renewable power sources in the world today.The U.S.Department of Energy(DOE)initiated the Wind Vision study where the costs and benefits of continued investments on wind energy was quantified.The study evaluated an ambitious,yet credible scenario in which wind energy will serve 20%of the nation’s total electric power demand by 2030,and 35%by 2050.In Europe,the wind power generation accounted for 15%of all European electricity demand in the past year.Wind power installation in China has been growing by an annual rate of^10%in recent years.Currently,wind power has become the second largest renewable energy in China,only after hydro-power.

关键词： Wind becoming continued

Flash memory based on MoTe_(2)/boron nitride/graphene semifloating gate heterostructure with non-volatile and dynamically tunable polarity

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Nano Research 2022年第7期15卷 6507-6514页

作者： Shijie Wang Guangyu Geng Yang Sun Sen Wu Xiaodong Hu Enxiu Wu Jing Liu School of Precision Instruments and Opto-electronics Engineering Tianjin UniversityTianjin 300072China State Key Laboratory of Precision Measurement Technology and Instruments Tianjin 300072China

Atomically thin two-dimensional(2D)materials are promising candidates to develop flash memories with premium performances as compared to conventional bulk materials,because of their ultra-thin thickness and highly tunable electrical properties.So far,most of the reported 2D material based flash memories work in the uni-polar mode,which usually further integrate additional local gate to achieve bi-polar function.However,such approach is volatile,meaning that the gate bias has to be applied persistently to maintain the polarity change and thus increases the power consumption.Here,we report a bi-polar memory based on MoTe_(2)/h-BN/graphene semi-floating gate(SFG)heterostructure,which has non-volatile and dynamically tunable polarity.The SFG configuration has the channel layer of MoTe_(2) and dielectric layer of h-BN half-stacked on the floating gate layer of graphene.The off-graphene half of the MoTe_(2) channel can be tuned between n-type and p-type by simultaneously applying ultraviolet(UV)illumination and electrical field through the back gate,which maintains this polarity after the removal of both stimuli.As a result,the SFG memory can work in the non-volatile bi-polar mode,with a on/off ratio of~100 and switching speed of 1 ms.On the other hand,the on-graphene half of the MoTe_(2) channel remains n-type under UV illumination and electrical bias,so that the MoTe_(2) full floating gate memory maintains n-type,which implements the integration of both n-and p-type memories in a single 2D heterostructure.This capability provides great flexibility for memory devices adapting in various emerging applications.

关键词： polarity modulation ultraviolet light semi-floating gate nonvolatile

Capillary electroosmosis properties of water lubricants with different electroosmotic additives under a steel-on-steel sliding interface

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Friction 2022年第7期10卷 1019-1034页

作者： Bohua FENG Zhiqiang LUAN Tao ZHANG Jiawei LIU Xiaodong Hu Jiju GUAN Xuefeng XU Key Laboratory of Special Purpose Equipment and Advanced Manufacturing Technology Ministry of Education&Zhejiang ProvinceZhejiang University of TechnologyHangzhou 310023China College of Mechanical Engineering Changshu Institute of TechnologyChangshu 215500China

The process of lubricant penetration into frictional interfaces has not been fully established,hence compromising their tribological performance.In this study,the penetration characteristics of deionized water(DI water)containing an electroosmotic suppressant(cetyltrimethylammonium bromide(CTAB))and an electroosmotic promoter(sodium lauriminodipropionate(SLI)),were investigated using steel-onsteel friction pairs.The results indicated that the lubricant with electroosmotic promoter reduced the coefficient of friction and wear scar diameter,whereas that with an electroosmotic suppressant exhibited an opposite behavior compared with DI water.The addition of SLI promoted the penetration of the DI water solution,thus resulting in the formation of a thick lubricating film of iron oxide at the sliding surface.This effectively reduced the abrasion damage,leading to a lower coefficient of friction and wear loss.

关键词： electroosmosis friction interface electroosmotic additives water lubricants tribological performance

Distribution Characteristics and Controlling Factors of Heavy Metals in Surface Sediments from the Bay-Island-Estuary System(BIES):A Case Study in Coastal Waters of Fujian Province,China

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中国海洋大学学报:英文版 2023年第5期22卷 1253-1268页

作者： LIU Bo hu Rijun WANG Yonghong LI Yi Zhu Longhai ZHANG xiaodong YUAN xiaodong College of Marine Geosciences Ocean University of ChinaQingdao 266100China Key Laboratory of Submarine Geosciences and Prospecting Techniques Ministry of EducationOcean University of ChinaQingdao 26610China huaneng Xiapu Nuclear Power Co.Ltd. Ningde 352000China

Based on the contents of six heavy metal elements in surface sediments from coastal areas of Fujian Province,the distribution characteristics and controlling factors of six heavy metals in a bay-island-estuary system(BIES)were studied.This paper focuses on the influence of the hydrodynamic environment,and systematically discusses how grain size compositions,chemical environment,tidal current,ocean circulation and human activities influence the distribution and transportation of the heavy metals.The results indicated that the distribution and migration of Cu,Pb,Zn and Cr elements were mainly controlled by natural factors such as regional geological background,grain size compositions,and tidal residual currents.In contrast,As and Hg was mainly affected by human factors such as agriculture and industrial manufacturing.In the BIES,where the chemical environment exerted limited influence,the accumulation and migration of heavy metals are mainly influenced by human activities and enhanced by estuary processes as well as the complex sedimentary dynamic environment caused by many bays and islands.

关键词： heavy metals sediments source to sink controlling factors hydrodynamic environment