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A 124 dB dynamic range sigma-delta modulator applied to non-invasive EEG acquisition using chopper-modulated input-scaling-down technique

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Science China(Information Sciences) 2022年第4期65卷 23-37页

作者： Kaiquan CHEN Mingyi CHEN Longlong CHENG liang QI Guoxing WANG yong LIAN Department of Micro/Nano Electronics Shanghai Jiao Tong University China Electronic Cloud Brain (Tianjin) Technology Co. Ltd.

With the advancement of brain science in recent years, the non-invasive brain-computer interfaces（BCIs） based on electroencephalogram（EEG） acquisition have been widely adopted in various brain-inspired applications. The acquisition of multi-channel microvolts EEG signals corrupted by the motion artifacts（MAs） of up to several volts poses enormous challenges to the design of analog front-end（AFE）, especially the analog-to-digital converter（ADC）, which is necessary to achieve low noise, wide dynamic range（DR）,high accuracy as well as low power. In this paper, a wide DR Σ△ modulator with chopper-modulated inputscaling-down（CM-ISD） technique has been proposed to deal with large input offset while extending dynamic range. Fabricated in 180 nm CMOS technology, the prototype occupies a core area of 0.32 mm;. With a 40 Hz input signal and 125 Hz Nyquist bandwidth, the measured signal-to-noise ratio（SNR） and signalto-noise and distortion ratio（SNDR） are 117 and 110 dB, respectively. Thanks to the proposed CM-ISD technique, the modulator is capable of withstanding a full-scale(4.5 V;) input whereas the measured DR has been extended from 99 to 124 dB. The power consumption is 2.75 mW under 5 V supply voltage,corresponding to 170.6 dB Schreier figure-of-merit（FoMS）. The multi-channel EEG acquisition has been demonstrated based on the proposed modulator, showing its potential in advanced non-invasive BCI systems.

关键词： Analog-to-digital converter (ADC) ΣΔ modulator brain computer interface electroencephalogram dynamic range motion artifacts

A robust QRS detection and accurate R-peak identification algorithm for wearable ECG sensors

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Science China(Information Sciences) 2021年第8期64卷 213-229页

作者： Kai ZHAO yongfu LI Guoxing WANG Yu PU yong LIAN Department of Micro and Nano Electronics Shanghai Jiao Tong University Alibaba Group

This paper presents a robust QRS detection algorithm that is capable of detecting QRS complexes as well as accurately identifying R-peaks. The proposed bilateral threshold scheme combined with QRS watchdog greatly improves the detection accuracy and robustness, resulting in consistent detection performance on 9 available ECG databases. Simulations show that the proposed algorithm achieves good results on the datasets from both QTDB healthy database and MITDB arrhythmia database, i.e. the sensitivity of99.99% and 99.88%, the precision of 99.98% and 99.88%, and the detection error rate of 0.04% and 0.31%,respectively. Furthermore, it also outperforms many existing algorithms on six other ECG databases, such as NSTDB, TWADB, STDB, SVDB, AFTDB, and FANTASIADB.

关键词： signal processing QRS detection R-peak detection wearable ECG sensors bilateral threshold

An interface shear damage model of chromium coating/steel substrate under thermal erosion load

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Defence Technology（防务技术） 2021年第2期17卷 405-415页

作者： Xiao-long Li yong Zang yong LIAN Min-yu Ma Lei Mu Qin Qin School of Mechanical Engineering University of Science and Technology BeijingBeijing100083China Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing100083China Beijing Key Laboratory for Corrosion Erosion and Surface TechnologyBeijing100083China

The Cr-plated coating inside a gun barrel can effectively improve the barrel’s erosion resistance and thus increase the service life.However,due to the cyclic thermal load caused by high-temperature gunpowder,micro-element damage tends to occur within the Cr coating/steel substrate interface,leading to a gradual deterioration in macro-mechanical properties for the material in the related region.In order to mimic this cyclic thermal load and,thereby,study the thermal erosion behavior of the Cr coating on the barrel’s inner wall,a laser emitter is utilized in the current study.With the help of in-situ tensile test and finite element simulation results,a shear stress distribution law of the Cr coating/steel substrate and a change law of the interface ultimate shear strength are identified.Studies have shown that the Cr coating/steel substrate interface’s ultimate shear strength has a significant weakening effect due to increasing temperature.In this study,the interfacial ultimate shear strength decreases from 2.57 GPa(no erosion)to 1.02 GPa(laser power is 160 W).The data from this experiment is employed to establish a Cr coating/steel substrate interface shear damage model.And this model is used to predict the flaking process of Cr coating by finite element method.The simulation results show that the increase of coating crack spacing and coating thickness will increase the service life of gun barrel.

关键词： Cr coating/steel substrate Thermal erosion Finite element simulation Ultimate shear strength Interface shear damage model

Screening and evaluation for antibiosis resistance of the spring wheat accessions to the grain aphid,Sitobion miscanthi(Takahashi)(Hemiptera:Aphididae)

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Journal of Integrative Agriculture 2022年第8期21卷 2329-2344页

作者： Kifle Gebreegziabiher GEBRETSADIK ZHANG yong CHEN Ju-lian State Key Laboratory for Biology of Plant Diseases and Insect Pests Institute of Plant ProtectionChinese Academy of Agricultural SciencesBeijing 100193P.R.China Tigray Agricultural Research Institute Mekelle 492Ethiopia

Resistant cultivar deployment is an effective method for cereal aphid management.Under greenhouse conditions,preliminary antibiosis resistance screening was conducted on 114 Ethiopian and 22 Chinese spring wheat accessions.After performing a bioassay to determine antibiosis resistance,aphid feeding behaviour and phenolic acid content analyses were performed on the aphid resistant wheat accessions by electrical penetration graph(EPG)and high performance liquid chromatography(HPLC),respectively.Among the wheat accessions,two high resistances,27moderate-resistances,and 35 low-resistances to Sitobion miscanthi were identified.The antibiosis resistance test showed prolonged pre-adult and pre-reproductive periods,shorter reproductive periods,lower fecundity,an intrinsic rate(rm)of increase,and a finite rate(λ)of increase of S.miscanthi on Lunxuan 145,Wane,Lunxuan 6,204511,Lunxuan 103and 5215 than those on the aphid-susceptible accession Beijing 837.The changes for the parameters of aphid feeding behaviour,including spending a longer time in the penetration and phloem salivation phases and less time in the phloem sap-feeding phase on the resistant wheat accessions,indicated that the aphid resistance may occur during the phloem phase and may be due to difficulties in the mechanical probing of the mesophyll cells.Additionally,the HPLC analysis showed higher contents of:1)ferulic acid in Lunxuan 145,Lunxuan 103 and Lunxuan 6;2)p-coumaric acid in Lunxuan145;3)vanillic acid in Lunxuan 145,Wane and Lunxuan 6;4)syringic acid in Lunxuan 103;and 5)caffeic acid in 5215.The contents of some phenolic acids within wheat leaves,such as p-courmaric acid and vanillic acid showed significant positive correlation with the duration of aphid development,but negative correlation with the aphid fecundity.The concentrations of these acids may be the causes of antibiosis resistance to S.miscanthi.The identification of grain aphid-resistant wheat accessions in our study will be helpful in future breeding program for pest control.

关键词： Sitobion miscanthi spring wheat accessions antibiosis resistance electronic penetration graph high-performance liquid chromatography phenolic acid concentrations

Glass Recognition and Map Optimization Method for Mobile Robot Based on Boundary Guidance

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Chinese Journal of Mechanical Engineering 2023年第3期36卷 135-146页

作者： yong Tao He Gao Yufang Wen lian Duan Jiangbo Lan School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Research Institute of Aero-Engine Beihang UniversityBeijing 102206China Large Aircraft Advanced Training Center Beihang UniversityBeijing 100191China

Current research on autonomous mobile robots focuses primarily on perceptual accuracy and autonomous performance.In commercial and domestic constructions,concrete,wood,and glass are typically used.Laser and visual mapping or planning algorithms are highly accurate in mapping wood panels and concrete walls.However,indoor and outdoor glass curtain walls may fail to perceive these transparent materials.In this study,a novel indoor glass recognition and map optimization method based on boundary guidance is proposed.First,the status of glass recognition techniques is analyzed comprehensively.Next,a glass image segmentation network based on boundary data guidance and the optimization of a planning map based on depth repair are proposed.Finally,map optimization and path-planning tests are conducted and compared using different algorithms.The results confirm the favorable adaptability of the proposed method to indoor transparent plates and glass curtain walls.Using the proposed method,the recognition accuracy of a public test set increases to 94.1%.After adding the planning map,incorrect coverage redundancies for two test scenes reduce by 59.84%and 55.7%.Herein,a glass recognition and map optimization method is proposed that offers sufficient capacity in perceiving indoor glass materials and recognizing indoor no-entry regions.

关键词： Autonomous mobile robot Multi-sensor fusion Glass recognition Map optimization

Interdecadal Enhancement in the Relationship between the Western North Pacific Summer Monsoon and Sea Surface Temperature in the Tropical Central-Western Pacific after the Early 1990s

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Advances in Atmospheric Sciences 2023年第10期40卷 1766-1782页

作者： Kui LIU lian-Tong ZHOU Zhibiao WANG yong LIU College of Geography and Tourism Hengyang Normal UniversityHengyang 421008China Center of Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

This study reveals the strengthened interdecadal relationship between the western North Pacific summer monsoon(WNPSM)and tropical central-western Pacific sea surface temperature anomaly(SSTA)in summer after the early 1990s.In the first period(1979–91,P1),the WNPSM-related precipitation anomaly and horizontal wind anomaly present themselves as an analogous Pacific-Japan(PJ)-like pattern,generally considered to be related to the Niño-3 index in the preceding winter.During the subsequent period(1994–2019,P2),the WNPSM-related precipitation anomaly presents a zonal dipole pattern,correlated significantly with the concurrent SSTA in the Niño-4 and tropical western Pacific regions.The negative(positive)SSTA in the tropical western Pacific and positive(negative)SSTA in the Niño-4 region,could work together to influence the WNPSM,noting that the two types of anomalous SSTA configurations enhance(weaken)the WNPSM by the positive(negative)phase PJ-like wave and Gill response,respectively,with an anomalous cyclone(anticyclone)located in the WNPSM,which shows obvious symmetry about the anomalous circulation.Specifically,the SSTA in Niño-4 impacts the WNPSM by an atmospheric Gill response,with a stronger(weaker)WNPSM along with a positive(negative)SSTA in the Niño-4 region.Furthermore,the SSTA in the tropical western Pacific exerts an influence on the WNPSM by a PJ-like wave,with a stronger(weaker)WNPSM along with a negative(positive)SSTA in the tropical western Pacific.In general,SSTAs in the tropical western Pacific and Niño-4 areas could work together to exert influence on the WNPSM,with the effect most likely to occur in the El Niño(La Niña)developing year in P2.However,the SSTAs in the tropical western Pacific worked alone to exert an influence on the WNPSM mainly in 2013,2014,2016,and 2017,and the SSTAs in the Niño-4 region worked alone to exert an influence on the WNPSM mainly in Central Pacific(CP)La Niña developing years.The sensitivity experiments also can reproduce the PJ-like wave/Gill response associated with SST

关键词： western North Pacific summer monsoon tropical central-western Pacific SST interdecadal change

A review on ignition mechanisms and characteristics of magnesium alloys

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Journal of Magnesium and Alloys 2020年第2期8卷 329-344页

作者： Dong Han Jin Zhang Jinfeng Huang yong LIAN Guangyu He University of Science and Technology 30 Xueyuan RoadHaidian DistrictBeijing 100083PR China Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi'anShanxi 710038PR China

Magnesium alloys have become more attractive because of their low density and electromagnetic shielding effectiveness in the aerospace industry.However,some unpredictable situation may lead to the ignition of magnesium alloys.In this review,the thermodynamic conditions and transfer processes of magnesium alloys ignition are analyzed from the point of mechanisms.The criteria of ignition are emphasized.In addition,ignitability and flammability test systems are compared.And a more suitable method to assess the potential ignition and flammability risks of magnesium alloys in extreme environments is recommended.Furthermore,the ignition characteristics of magnesium alloys are discussed in detail.It was found that the ignition of magnesium alloys is a complex process determined by internal properties such as thermo-physical properties,oxide film properties,chemical compositions and geometrical parameters,as well as the external environment such as gas species,oxygen concentration and oxygen pressure.Ignition temperature is not physical constants of materials.It is not simply assumed that ignition may occur when the temperature of Mg alloys reaches a certain ignition point.Finally,the unsolved issues in the ignition of magnesium alloys are pointed out and the future investigation are suggested for improving the safety and reliability of magnesium alloys in the aerospace applications.

关键词： Magnesium alloys Ignition mechanisms Ignition characteristics

Detection of the interictal epileptic discharges based on wavelet bispectrum interaction and recurrent neural network

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Science China(Information Sciences) 2021年第6期64卷 203-221页

作者： Nabil SABOR yongfu LI Zhe ZHANG Yu PU Guoxing WANG yong LIAN Department of Micro-Nano Electronics Shanghai Jiao Tong University Electrical Engineering Department Assiut University MoE Key Lab of Artificial Intelligence Shanghai Jiao Tong University Alibaba DAMO Academy

Detection of interictal epileptic discharges(IED) events in the EEG recordings is a critical indicator for detecting and diagnosing epileptic seizures. We propose a key technology to extract the most important features related to epileptic seizures and identifies the IED events based on the interaction between frequencies of EEG with the help of a two-level recurrent neural network. The proposed classification network is trained and validated using the largest publicly available EEG dataset from Temple University Hospital.Experimental results clarified that the interaction between β and β bands, β and γ bands, γ and γ bands,δ and δ bands, θ and α bands, and θ and β bands have a significant effect on detecting the IED discharges.Moreover, the obtained results showed that the proposed technique detects 95.36% of the IED epileptic events with a false-alarm rate of 4.52% and a precision of 87.33% by using only 25 significant features. Furthermore,the proposed system requires only 164 ms for detecting a 1-s IED event which makes it suitable for real-time applications.

关键词： interictal epileptic discharges epilepsy discrete wavelet transform wavelet bispectrum long short-term memory recurrent neural network

Acid Phosphatase Activity May Affect the Tuber Swelling by Partially Regulating Sucrose-mediated Sugar Resorption in Potato

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Journal of Integrative Plant Biology 2008年第6期50卷 733-741页

作者： Da-yong Wang yong LIAN De-Wei Zhu Department of Genetics and Developmental Biology Southeast University Nanjing 210009 China Key Laboratory of Developmental Genes and Human Disease Ministry of Education Nanjing 210009 China Institute of Vegetative and Flowers Chinese Academy of Agncultural Sciences Beijing 100081 China

APase activity is involved in regulating many physiological and developmental events by affecting the resorption process. In this study, we investigate the role of APase activity in tuber development in potato. APase activities were mainly localized in cytoplasm, gaps among cells and stroma of amyloplasts of parenchyma cells at the stage of tuber swelling. AP1, encoding a putative APase, was also highly expressed in swelling tubers and a low level of expression was observed in elongated stolons and matured tubers. Inhibition of APase activity by applying Brefeldin A, an inhibitor of APase production and secretion, significantly suppressed the tuber swelling and moderately affected the stolon elongation and the tuberization frequency. During tuber development, sucrose serves as the main soluble sugar for long-distance transportation and resorption. Moreover, inhibition of APase activity by Brefeldin A markedly reduced the sucrose content in tubers and further decreased the starch accumulation, suggesting that the function of APase in regulating the tuber swelling might be at least partially mediated by the sugar resorption. Exogenous sucrose treatments further indicate the important role of sucrose-mediated sugar resorption in tuber swelling. These results suggest that the APase activity might affect the tuber swelling by partially regulating the sucrose-mediated sugar resorption.

关键词： APase activity potato sucrose-mediated sugar resorption tuber swelling